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Sample records for amazonian populations spatial

  1. Hair mercury levels in Amazonian populations: spatial distribution and trends

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    Barbieri Flavia L

    2009-12-01

    Full Text Available Abstract Background Mercury is present in the Amazonian aquatic environments from both natural and anthropogenic sources. As a consequence, many riverside populations are exposed to methylmercury, a highly toxic organic form of mercury, because of their intense fish consumption. Many studies have analysed this exposure from different approaches since the early nineties. This review aims to systematize the information in spatial distribution, comparing hair mercury levels by studied population and Amazonian river basin, looking for exposure trends. Methods The reviewed papers were selected from scientific databases and online libraries. We included studies with a direct measure of hair mercury concentrations in a sample size larger than 10 people, without considering the objectives, approach of the study or mercury speciation. The results are presented in tables and maps by river basin, displaying hair mercury levels and specifying the studied population and health impact, if any. Results The majority of the studies have been carried out in communities from the central Amazonian regions, particularly on the Tapajós River basin. The results seem quite variable; hair mercury means range from 1.1 to 34.2 μg/g. Most studies did not show any significant difference in hair mercury levels by gender or age. Overall, authors emphasized fish consumption frequency as the main risk factor of exposure. The most studied adverse health effect is by far the neurological performance, especially motricity. However, it is not possible to conclude on the relation between hair mercury levels and health impact in the Amazonian situation because of the relatively small number of studies. Conclusions Hair mercury levels in the Amazonian regions seem to be very heterogenic, depending on several factors. There is no obvious spatial trend and there are many areas that have never been studied. Taking into account the low mercury levels currently handled as acceptable, the

  2. Spatial patterns of grasses influence soil macrofauna biodiversity in Amazonian pastures

    OpenAIRE

    Mathieu, J.; Grimaldi, Michel; Jouquet, Pascal; Rouland, Corinne; Lavelle, Patrick; Desjardins, Thierry; Rossi, J. P.

    2009-01-01

    Grasslands are often characterized by small-scale spatial heterogeneity due to the juxtaposition of grass tufts and bare ground. Although the mechanisms generating plant spatial patterns have been widely studied, few studies concentrated on the consequences of these patterns on belowground macrofauna. Our objective was to analyze the impact of grass tuft (Brachiaria bryzantha cv. marandu) spatial distribution on soil macrofauna diversity in Amazonian pastures, at a small scale (less than 9 m(...

  3. Mitochondrial DNA mapping of social-biological interactions in Brazilian Amazonian African-descendant populations

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    Bruno Maia Carvalho

    2008-01-01

    Full Text Available The formation of the Brazilian Amazonian population has historically involved three main ethnic groups, Amerindian, African and European. This has resulted in genetic investigations having been carried out using classical polymorphisms and molecular markers. To better understand the genetic variability and the micro-evolutionary processes acting in human groups in the Brazilian Amazon region we used mitochondrial DNA to investigate 159 maternally unrelated individuals from five Amazonian African-descendant communities. The mitochondrial lineage distribution indicated a contribution of 50.2% from Africans (L0, L1, L2, and L3, 46.6% from Amerindians (haplogroups A, B, C and D and a small European contribution of 1.3%. These results indicated high genetic diversity in the Amerindian and African lineage groups, suggesting that the Brazilian Amazonian African-descendant populations reflect a possible population amalgamation of Amerindian women from different Amazonian indigenous tribes and African women from different geographic regions of Africa who had been brought to Brazil as slaves. The present study partially mapped the historical biological and social interactions that had occurred during the formation and expansion of Amazonian African-descendant communities.

  4. Diversity and genetic structure analysis of three Amazonian Amerindian populations from Colombia

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    Yamid Braga

    2012-06-01

    Full Text Available Introduction: In the departments of the Vaupés and Guaviare, in southeastern Colombia, in a transitional area between Amazonia and the eastern plains, inhabit indigenous groups belonging to the Tukanoan (East and Guahiban linguistic families. Although some studies have dealt with the culture and the cosmology description of these groups, little research has been done on the biological diversity and genetic relationships of such groups.Objective: To estimate the diversity, the structure, and the genetic relationships of one Guahiban and two Tukanoan groups of the Colombian Amazonian region.Methods: Samples were collected (n = 106 from unrelated individuals belonging to the Vaupés native indigenous communities. The DNA was extracted and nine autosomal microsatellites were typed. Several measures of diversity, FST, pairwise FST, and population differentiation between groups were calculated. Finally, it was estimated the genetic distances of the groups studied in relation with other Amazonian, Andean and Central American indigenous people.Results: 1. The genetic diversity found stands within the range of other Amazonian populations, whereas compared to the mestizo and afro-descendant Colombian populations, such diversity showed to be lower. 2. The structure and population differentiation tests showed two clusters; one consisting of the Vaupés Tukanoan and Guaviare Tukanoan groups, and a second one formed by the Guayabero. 3. Tukanoan groups are found to be closer related to the Brazilian Amazonian populations than to the Guayabero.Conclusion: The results of this study suggest that the Guayabero group from Guaviare, are genetically differentiated from those Tukanoan groups of the Vaupés and Guaviare.

  5. Diversity and genetic structure analysis of three Amazonian Amerindian populations from Colombia

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    Yamid Braga

    2012-06-01

    Full Text Available 14.00 Normal 0 21 false false false ES-CO X-NONE X-NONE Introduction: In the departments of the Vaupés and Guaviare, in southeastern Colombia, in a transitional area between Amazonia and the eastern plains, inhabit indigenous groups belonging to the Tukanoan (East and Guahiban linguistic families. Although some studies have dealt with the culture and the cosmology description of these groups, little research has been done on the biological diversity and genetic relationships of such groups. Objective: To estimate the diversity, the structure, and the genetic relationships of one Guahiban and two Tukanoan groups of the Colombian Amazonian region. Methods: Samples were collected (n = 106 from unrelated individuals belonging to the Vaupés native indigenous commu­nities. The DNA was extracted and nine autosomal microsatellites were typed. Several measures of diversity, FST, pairwise FST, and population differentiation between groups were calculated. Finally, it was estimated the genetic distances of the groups studied in relation with other Amazonian, Andean and Central American indigenous people. Results: 1. The genetic diversity found stands within the range of other Amazonian populations, whereas compared to the mestizo and afro-descendant Colombian populations, such diversity showed to be lower. 2. The structure and population differentiation tests showed two clusters; one consisting of the Vaupés Tukanoan and Guaviare Tukanoan groups, and a second one formed by the Guayabero. 3. Tukanoan groups are found to be closer related to the Brazilian Amazonian po­pulations than to the Guayabero. Conclusion: The results of this study suggest that the Guayabero group from Guaviare, are genetically differentiated from those Tukanoan groups of the Vaupés and Guaviare

  6. Physical growth of the shuar: Height, Weight, and BMI references for an indigenous amazonian population

    OpenAIRE

    Urlacher, SS; Blackwell, AD; Liebert, MA; Madimenos, FC; Cepon-Robins, TJ; Gildner, TE; Snodgrass, JJ; Sugiyama, LS

    2016-01-01

    © 2015 Wiley Periodicals, Inc. Objectives: Information concerning physical growth among small-scale populations remains limited, yet such data are critical to local health efforts and to foster basic understandings of human life history and variation in childhood development. Using a large dataset and robust modeling methods, this study aims to describe growth from birth to adulthood among the indigenous Shuar of Amazonian Ecuador. Methods: Mixed-longitudinal measures of height, weight, and b...

  7. Modeling disease vector occurrence when detection is imperfect: infestation of Amazonian palm trees by triatomine bugs at three spatial scales.

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    Fernando Abad-Franch

    Full Text Available BACKGROUND: Failure to detect a disease agent or vector where it actually occurs constitutes a serious drawback in epidemiology. In the pervasive situation where no sampling technique is perfect, the explicit analytical treatment of detection failure becomes a key step in the estimation of epidemiological parameters. We illustrate this approach with a study of Attalea palm tree infestation by Rhodnius spp. (Triatominae, the most important vectors of Chagas disease (CD in northern South America. METHODOLOGY/PRINCIPAL FINDINGS: The probability of detecting triatomines in infested palms is estimated by repeatedly sampling each palm. This knowledge is used to derive an unbiased estimate of the biologically relevant probability of palm infestation. We combine maximum-likelihood analysis and information-theoretic model selection to test the relationships between environmental covariates and infestation of 298 Amazonian palm trees over three spatial scales: region within Amazonia, landscape, and individual palm. Palm infestation estimates are high (40-60% across regions, and well above the observed infestation rate (24%. Detection probability is higher ( approximately 0.55 on average in the richest-soil region than elsewhere ( approximately 0.08. Infestation estimates are similar in forest and rural areas, but lower in urban landscapes. Finally, individual palm covariates (accumulated organic matter and stem height explain most of infestation rate variation. CONCLUSIONS/SIGNIFICANCE: Individual palm attributes appear as key drivers of infestation, suggesting that CD surveillance must incorporate local-scale knowledge and that peridomestic palm tree management might help lower transmission risk. Vector populations are probably denser in rich-soil sub-regions, where CD prevalence tends to be higher; this suggests a target for research on broad-scale risk mapping. Landscape-scale effects indicate that palm triatomine populations can endure deforestation

  8. Spatial distribution and functional significance of leaf lamina shape in Amazonian forest trees

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    A. C. M. Malhado

    2009-02-01

    Full Text Available Leaves in tropical forests come in an enormous variety of sizes and shapes, each of which can be ultimately viewed as an adaptation to the complex problem of optimising the capture of light for photosynthesis. However, the fact that many different shape "strategies" coexist within a habitat demonstrate that there are many other intrinsic and extrinsic factors involved, such as the differential investment in support tissues required for different leaf lamina shapes. Here, we take a macrogeographic approach to understanding the function of different lamina shape categories. Specifically, we use 106 permanent plots spread across the Amazon rainforest basin to: (1 describe the geographic distribution of some simple metrics of lamina shape in plots from across Amazonia, and; (2 identify and quantify relationships between key environmental parameters and lamina shape in tropical forests. Because the plots are not randomly distributed across the study area, achieving this latter objective requires the use of statistics that can account for spatial auto-correlation. We found that between 60–70% of the 2791 species and 83 908 individual trees in the dataset could be classified as elliptic (=the widest part of a leaf is on an axis in the middle fifth of the long axis of the leaf. Furthermore, the average Amazonian tree leaf is 2.5 times longer than it is wide and has an entire margin. Contrary to theoretical expectations we found little support for the hypothesis that narrow leaves are an adaptation to dry conditions and low nutrient soils. However, we did find strong regional patterns in leaf lamina length-width ratios and several significant correlations with precipitation variables suggesting that water availability may be exerting an as yet unrecognised selective pressure on leaf shape of rainforest trees. Furthermore, we found a strong correlation between the proportion of trees with non-entire laminas (dissected, toothed, etc. and mean annual

  9. Spatial distribution and functional significance of leaf lamina shape in Amazonian forest trees

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    A. C. M. Malhado

    2009-08-01

    Full Text Available Leaves in tropical forests come in an enormous variety of sizes and shapes, each of which can be ultimately viewed as an adaptation to the complex problem of optimising the capture of light for photosynthesis. However, the fact that many different shape "strategies" coexist within a habitat demonstrate that there are many other intrinsic and extrinsic factors involved, such as the differential investment in support tissues required for different leaf lamina shapes. Here, we take a macrogeographic approach to understanding the function of different lamina shape categories. Specifically, we use 106 permanent plots spread across the Amazon rainforest basin to: 1 describe the geographic distribution of some simple metrics of lamina shape in plots from across Amazonia, and; 2 identify and quantify relationships between key environmental parameters and lamina shape in tropical forests. Because the plots are not randomly distributed across the study area, achieving this latter objective requires the use of statistics that can account for spatial auto-correlation. We found that between 60–70% of the 2791 species and 83 908 individual trees in the dataset could be classified as having elliptic leaves (= the widest part of the leaf is on an axis in the middle fifth of the long axis of the leaf. Furthermore, the average Amazonian tree leaf is 2.5 times longer than it is wide and has an entire margin. Contrary to theoretical expectations we found little support for the hypothesis that narrow leaves are an adaptation to dry conditions. However, we did find strong regional patterns in leaf lamina length-width ratios and several significant correlations with precipitation variables suggesting that water availability may be exerting an as yet unrecognised selective pressure on leaf shape of rainforest trees. Some support was found for the hypothesis that narrow leaves are an adaptation to low nutrient soils. Furthermore, we found a strong correlation between

  10. The Genetic History of Peruvian Quechua-Lamistas and Chankas: Uniparental DNA Patterns among Autochthonous Amazonian and Andean Populations.

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    Sandoval, José R; Lacerda, Daniela R; Acosta, Oscar; Jota, Marilza S; Robles-Ruiz, Paulo; Salazar-Granara, Alberto; Vieira, Pedro Paulo R; Paz-Y-Miño, César; Fujita, Ricardo; Santos, Fabricio R

    2016-03-01

    This study focuses on the genetic history of the Quechua-Lamistas, inhabitants of the Lamas Province in the San Martin Department, Peru, who speak their own distinct variety of the Quechua family of languages. It has been suggested that different pre-Columbian ethnic groups from the Peruvian Amazonia, like the Motilones or "shaven heads", assimilated the Quechua language and then formed the current native population of Lamas. However, many Quechua-Lamistas claim to be direct descendants of the Chankas, a famous pre-Columbian indigenous group that escaped from Inca rule in the Andes. To investigate the Quechua-Lamistas and Chankas' ancestries, we compared uniparental genetic profiles (17 STRs of Q-M3 Y-chromosome and mtDNA complete control region haplotypes) among autochthonous Amazonian and Andean populations from Peru, Bolivia and Ecuador. The phylogeographic and population genetic analyses indicate a fairly heterogeneous ancestry for the Quechua-Lamistas, while they are closely related to their neighbours who speak Amazonian languages, presenting no direct relationships with populations from the region where the ancient Chankas lived. On the other hand, the genetic profiles of self-identified Chanka descendants living in Andahuaylas (located in the Apurimac Department, Peru, in the Central Andes) were closely related to those living in Huancavelica and the assumed Chanka Confederation area before the Inca expansion. PMID:26879156

  11. Afro-derived Amazonian populations: inferring continental ancestry and population substructure.

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    Lopes Maciel, Luana Gomes; Ribeiro Rodrigues, Elzemar Martins; Carneiro Dos Santos, Ney Pereira; Ribeiro Dos Santos, Ândrea; Guerreiro, João Farias; Santos, Sidney

    2011-10-01

    A panel of Ancestry Informative Markers (AIMs) was used to identify population substructure and estimate individual and overall interethnic admixture in 294 individuals from seven African-derived communities of the Brazilian Amazon. A panel of 48 biallelic markers, representing the insertion (IN) or the deletion (DEL) of small DNA fragments, was employed for this purpose. Overall interethnic admixture estimates showed high miscegenation with other ethnic groups in all populations (between 46% and 64%). The proportion of ancestral genes varied significantly among individuals of the sample: the contribution of African genes varied between 12% and 75%; of European genes between 10% and 73%; and of Amerindians genes between 8% and 66%. The obtained data reveal a high contribution of Amerindian genes in these communities, unlike in other African-derived communities of the Northeast and the South of Brazil. In addition, the majority of the Amerindian contribution may result from the preferential inclusion of indigenous women in the African descent groups. High heterogeneity of the proportion of interethnic admixture among analyzed individuals was found when the proportion of ancestral genes of each individual of the sample was estimated. This heterogeneity is reflected in the fact that four populations can be considered as substructured and that the global African descent sample is possibly formed by two subpopulations. PMID:22146065

  12. Spatial and temporal changes in bird assemblages in forest fragments in an eastern Amazonian savannah.

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    Cintra, Renato; Magnusson, William E; Albernaz, Ana

    2013-09-01

    We investigated the effects of forest fragmentation on bird assemblages in an Amazonian savannah landscape with forest fragments that have been isolated for more than 100 years. The study was conducted in areas surrounding the village of Alter do Chão (2°31'S, 55°00'W), Santarém, Brazil. Bird surveys and measurements of tree density were undertaken in 25 areas, with 19 plots in forest fragments of different sizes and six in an area of continuous forest. Data on forest-fragment size, perimeter, and isolation were obtained from a georeferenced satellite image. Variation in number of bird species recorded per plot was not related to vegetation structure (tree density). The number of bird species recorded per plot increased significantly only with fragment area, but was not influenced by fragment shape or degree of isolation, even when considering species from the savannah matrix in the analysis. Fragments had fewer rare species. Multivariate ordination analyses (multiple dimensional scaling, [MDS]) indicated that bird species composition changed along a gradient from small to large forest fragments and continuous-forest areas. In the Amazonian savannah landscapes of Alter do Chão, the organization and composition of bird assemblages in forest fragments are affected by local long-term forest-fragmentation processes. Differences in the number of bird species recorded per plot and assemblage composition between forest fragments and continuous forest were not influenced by forest structure, suggesting that the observed patterns in species composition result from the effects of fragmentation per se rather than from preexisting differences in vegetation structure between sites. Nevertheless, despite their long history of isolation, the forest fragments still preserve a large proportion (on average 80%) of the avifauna found in continuous-forest areas. The fragments at Alter do Chão are surrounded by natural (rather than planted) grassland, with many trees in the

  13. Spatial distributions and productivity in salmonid populations

    OpenAIRE

    Foldvik, Anders

    2013-01-01

    This thesis presents analysis and fieldwork investigating how the effect spatial distributions and spatial relationships have on population growth in two anadromous salmonid species, Atlantic salmon and brown trout. The thesis looks at how the spatial distribution of spawning within a river can shape the distribution of juveniles within a river throughout their freshwater stage, and investigates how habitat characteristics, ranging in spatial scale from micro-habitat to catchment, affect popu...

  14. Amazonian malaria: Asymptomatic human reservoirs, diagnostic challenges, environmentally-driven changes in mosquito vector populations, and the mandate for sustainable control strategies

    OpenAIRE

    da Silva-Nunes, Mônica; Moreno, Marta; Jan E Conn; Gamboa, Dionicia; Abeles, Shira; Vinetz, Joseph M.; Ferreira, Marcelo U.

    2011-01-01

    Across the Americas and the Caribbean, nearly 561,000 slide-confirmed malaria infections were reported officially in 2008. The nine Amazonian countries accounted for 89% of these infections; Brazil and Peru alone contributed 56% and 7% of them, respectively. Local populations of the relatively neglected parasite P. vivax, which currently accounts for 77% of the regional malaria burden, are extremely diverse genetically and geographically structured. At a time when malaria elimination is place...

  15. Molecular heterogeneity of G6PD deficiency in an Amazonian population and description of four new variants.

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    Hamel, Arno Rolf; Cabral, Isabel Rosa; Sales, Tereza Sueko Ide; Costa, Fernando Ferreira; Olalla Saad, Sara Teresinha

    2002-01-01

    To characterize the molecular variation in the glucose-6-phosphate dehydrogenase gene (G6PD), 196 asymptomatic and unrelated male G6PD-deficient blood donors from Belém, an Amazonian metropolis (Brazil), were analyzed. This deficiency was detected by horizontal agarose gel electrophoresis and quantitative spectrophotometric assay for enzyme activity. The mutations were searched by PCR/RFLP, SSCP, and direct DNA sequencing. The most frequent G6PD variant was the widespread and common G6PD A- (202G --> A, 376A --> G) observed in 161 subjects (82.1%). Besides this, we found another form of G6PD A- (968T --> C, 376A --> G) in 14 (7.1%) individuals, G6PD Seattle (844G --> C) in 4.6%, G6PD Santamaria (542A --> T, 376A --> G) in 2.5%, and G6PD Tokyo (1246G --> A) in one blood donor. Four novel variants were also identified: G6PD Belém (409C --> T; Pro137His), G6PD Ananindeua (376A --> G, 871G --> A; Asn126Asp, Val291Met), G6PD Crispim with four point mutations (375G --> T, 379G --> T, 383T --> C, and 384C --> T) leading to three amino acid substitutions (Met125Ile, Ala127Ser, and Leu128Pro), and G6PD Amazonia (185C --> A; Pro62His). The reported frequencies do not reflect the real values for blood donors from Belém, since an excess of individuals with "non A-" phenotype was included in this study to enhance the probability to find rare variants. Haplotype analyses were carried out for the less common G6PD variants identified in our study using PCR/RFLP for five polymorphic sites (FokI, PvuII, PstI, BclI, NlaIII). G6PD Crispim and G6PD Amazonia variants presented the most common haplotype found in G6PD B (- - + - -). G6PD Belém presented two haplotypes (- - + + +, - + + + +) and G6PD Ananindeua was found with the + - + - + haplotype. The reported heterogeneity probably is due to the great miscegenation, characteristic of the population of the Amazonian region, besides the apparently common occurrence of recurrent mutations in the G6PD gene. PMID:12367584

  16. Spatial distributions of niche-constructing populations

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    Xiaozhuo Han

    2015-12-01

    Full Text Available Niche construction theory regards organisms not only as the object of natural selection but also an active subject that can change their own selective pressure through eco-evolutionary feedbacks. Through reviewing the existing works on the theoretical models of niche construction, here we present the progress made on how niche construction influences genetic structure of spatially structured populations and the spatial-temporal dynamics of metapopulations, with special focuses on mathematical models and simulation methods. The majority of results confirmed that niche construction can significantly alter the evolutionary trajectories of structured populations. Organism-environmental interactions induced by niche construction can have profound influence on the dynamics, competition and diversity of metapopulations. It can affect fine-scale spatially distribution of species and spatial heterogeneity of the environment. We further propose a few research directions with potentials, such as applying adaptive dynamics or spatial game theory to explore the effect of niche construction on phenotypic evolution and diversification.

  17. Implications of market integration for cardiovascular and metabolic health among an indigenous Amazonian Ecuadorian population

    OpenAIRE

    Liebert, MA; Snodgrass, JJ; Madimenos, FC; Cepon, TJ; Blackwell, AD; Sugiyama, LS

    2013-01-01

    Background: Market integration (MI), the suite of social and cultural changes that occur with economic development, has been associated with negative health outcomes such as cardiovascular disease; however, key questions remain about how this transition manifests at the local level. Aim: The present paper investigates the effects of MI on health among Shuar, an indigenous lowland Ecuadorian population, with the goal of better understanding the mechanisms responsible for this health transition...

  18. Distinct population structure for co-occurring Anopheles goeldii and Anopheles triannulatus in Amazonian Brazil

    OpenAIRE

    Sascha Naomi McKeon; Marta Moreno; Maria Anise Sallum; Marinete Marins Povoa; Jan Evelyn Conn

    2013-01-01

    To evaluate whether environmental heterogeneity contributes to the genetic heterogeneity in Anopheles triannulatus, larval habitat characteristics across the Brazilian states of Roraima and Pará and genetic sequences were examined. A comparison with Anopheles goeldii was utilised to determine whether high genetic diversity was unique to An. triannulatus. Student t test and analysis of variance found no differences in habitat characteristics between the species. Analysis of population structur...

  19. Distinct population structure for co-occurring Anopheles goeldii and Anopheles triannulatus in Amazonian Brazil

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    Sascha Naomi McKeon

    2013-08-01

    Full Text Available To evaluate whether environmental heterogeneity contributes to the genetic heterogeneity in Anopheles triannulatus, larval habitat characteristics across the Brazilian states of Roraima and Pará and genetic sequences were examined. A comparison with Anopheles goeldii was utilised to determine whether high genetic diversity was unique to An. triannulatus. Student t test and analysis of variance found no differences in habitat characteristics between the species. Analysis of population structure of An. triannulatus and An. goeldii revealed distinct demographic histories in a largely overlapping geographic range. Cytochrome oxidase I sequence parsimony networks found geographic clustering for both species; however nuclear marker networks depicted An. triannulatus with a more complex history of fragmentation, secondary contact and recent divergence. Evidence of Pleistocene expansions suggests both species are more likely to be genetically structured by geographic and ecological barriers than demography. We hypothesise that niche partitioning is a driving force for diversity, particularly in An. triannulatus.

  20. Method for spatially distributing a population

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    Bright, Edward A [Knoxville, TN; Bhaduri, Budhendra L [Knoxville, TN; Coleman, Phillip R [Knoxville, TN; Dobson, Jerome E [Lawrence, KS

    2007-07-24

    A process for spatially distributing a population count within a geographically defined area can include the steps of logically correlating land usages apparent from a geographically defined area to geospatial features in the geographically defined area and allocating portions of the population count to regions of the geographically defined area having the land usages, according to the logical correlation. The process can also include weighing the logical correlation for determining the allocation of portions of the population count and storing the allocated portions within a searchable data store. The logically correlating step can include the step of logically correlating time-based land usages to geospatial features of the geographically defined area. The process can also include obtaining a population count for the geographically defined area, organizing the geographically defined area into a plurality of sectors, and verifying the allocated portions according to direct observation.

  1. Human population and socioeconomic modulators of conservation performance in 788 Amazonian and Atlantic Forest reserves.

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    de Marques, Ana Alice B; Schneider, Mauricio; Peres, Carlos A

    2016-01-01

    Protected areas form a quintessential component of the global strategy to perpetuate tropical biodiversity within relatively undisturbed wildlands, but they are becoming increasingly isolated by rapid agricultural encroachment. Here we consider a network of 788 forest protected areas (PAs) in the world's largest tropical country to examine the degree to which they remain intact, and their responses to multiple biophysical and socioeconomic variables potentially affecting natural habitat loss under varying contexts of rural development. PAs within the complex Brazilian National System of Conservation Units (SNUC) are broken down into two main classes-strictly protected and sustainable use. Collectively, these account for 22.6% of the forest biomes within Brazil's national territory, primarily within the Amazon and the Atlantic Forest, but are widely variable in size, ecoregional representation, management strategy, and the degree to which they are threatened by human activities both within and outside reserve boundaries. In particular, we examine the variation in habitat conversion rates in both strictly protected and sustainable use reserves as a function of the internal and external human population density, and levels of land-use revenue in adjacent human-dominated landscapes. Our results show that PAs surrounded by heavily settled agro-pastoral landscapes face much greater challenges in retaining their natural vegetation, and that strictly protected areas are considerably less degraded than sustainable use reserves, which can rival levels of habitat degradation within adjacent 10-km buffer areas outside. PMID:27478703

  2. Comparative dynamics of small mammal populations in treefall gaps and surrounding understorey within Amazonian rainforest

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    Beck, H.; Gaines, M.S.; Hines, J.E.; Nichols, J.D.

    2004-01-01

    Variation in food resource availability can have profound effects on habitat selection and dynamics of populations. Previous studies reported higher food resource availability and fruit removal in treefall gaps than in the understorey. Therefore, gaps have been considered 'keystone habitat' for Neotropical frugivore birds. Here we test if this prediction would also hold for terrestrial small mammals. In the Amazon, we quantified food resource availability in eleven treefall gaps and paired understorey habitats and used feeding experiments to test if two common terrestrial rodents (Oryzomys megacephalus and Proechimys spp.) would perceive differences between habitats. We live-trapped small mammals in eleven gaps and understorey sites for two years, and compared abundance, fitness components (survival and per capita recruitment) and dispersal of these two rodent species across gaps and understorey and seasons (rainy and dry). Our data indicated no differences in resource availability and consumption rate between habitats. Treefall gaps may represent a sink habitat for Oryzomys where individuals had lower fitness, apparently because of habitat-specific ant predation on early life stages, than in the understorey, the source habitat. Conversely, gaps may be source habitat for Proechimys where individuals had higher fitness, than in the understorey, the sink habitat. Our results suggest the presence of source-sink dynamics in a tropical gap-understorey landscape, where two rodent species perceive habitats differently. This may be a mechanism for their coexistence in a heterogeneous and species-diverse system.

  3. Stochastic population growth in spatially heterogeneous environments

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    Evans, Steven N; Schreiber, Sebastian J; Sen, Arnab

    2011-01-01

    Classical ecological theory predicts that environmental stochasticity increases extinction risk by reducing the average per-capita growth rate of populations. To understand the interactive effects of environmental stochasticity, spatial heterogeneity, and dispersal on population growth, we study the following model for population abundances in $n$ patches: the conditional law of $X_{t+dt}$ given $X_t=x$ is such that when $dt$ is small the conditional mean of $X_{t+dt}^i-X_t^i$ is approximately $[x^i\\mu_i+\\sum_j(x^j D_{ji}-x^i D_{ij})]dt$, where $X_t^i$ and $\\mu_i$ are the abundance and per capita growth rate in the $i$-th patch respectivly, and $D_{ij}$ is the dispersal rate from the $i$-th to the $j$-th patch, and the conditional covariance of $X_{t+dt}^i-X_t^i$ and $X_{t+dt}^j-X_t^j$ is approximately $x^i x^j \\sigma_{ij}dt$. We show for such a spatially extended population that if $S_t=(X_t^1+...+X_t^n)$ is the total population abundance, then $Y_t=X_t/S_t$, the vector of patch proportions, converges in law...

  4. Selection of Cooperation in Spatially Structured Populations

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    Yang, Hyunmo; Ghim, Cheol-Min

    The social dilemma games give rise to an emergence of cooperation in which altruistic individuals survive the natural selection at higher rate than random chance. We try to extend our understanding of this spatial reciprocity by including the impact of degree-degree correlation on the propensity toward prosocial behaviour in an otherwise well-mixed population. In a stochastic death-birth process with weak selection, we find that the disassortative degree mixing, or negative correlation between the degrees of neighbouring nodes significantly promotes the fixation of cooperators whereas the assortative mixing acts to suppress it. This is consistent with the fact that the spatial heterogeneity weakens the average tendency of a population to cooperate, which we describe in a unified scheme of the effective isothermality in coarse-grained networks. We also discuss the individual-level incentives that indirectly foster restructuring the social networks toward the more cooperative topologies.

  5. Externalities, Floating Population and Spatial Agglomeration

    Institute of Scientific and Technical Information of China (English)

    Du Yu; Wang Chuansheng; Fan Jie

    2007-01-01

    With the further development of socialist market economy,the mobility of factor markets in China,especially the labor market.is strengthened.Extemalities interacts with the agglomeration of productive factors.Under the framework of new economic geographg this article presents a theoretical model involving the endogenous population density affected by urban externalities.Results show that the population density is more concentrated around the center because the degree and extent of interaction between individuals intensifies when the distance from the center decreases.When there are several extemalifies resonurces,the aggregation of externalities changes the configuration of spatial factor allocation.These results fit well with the empirical facts about the decreasing density of floating population along the cities of Guangzhou,Dongguan and Shenzhen in Guangdong Province which is situat d in the eastern coast of the Pearl River Delta.We find that under the impacts of externalities released from Hong Kong into the coast,floating population Was more concentrated around Shenzhen and Dongguan,which are more adjacent to Hong Kong compared with Guangzhou City.

  6. Spatially-Explicit Testing of a General Aboveground Carbon Density Estimation Model in a Western Amazonian Forest Using Airborne LiDAR

    Directory of Open Access Journals (Sweden)

    Patricio Xavier Molina

    2015-12-01

    Full Text Available Mapping aboveground carbon density in tropical forests can support CO2 emission monitoring and provide benefits for national resource management. Although LiDAR technology has been shown to be useful for assessing carbon density patterns, the accuracy and generality of calibrations of LiDAR-based aboveground carbon density (ACD predictions with those obtained from field inventory techniques should be intensified in order to advance tropical forest carbon mapping. Here we present results from the application of a general ACD estimation model applied with small-footprint LiDAR data and field-based estimates of a 50-ha forest plot in Ecuador’s Yasuní National Park. Subplots used for calibration and validation of the general LiDAR equation were selected based on analysis of topographic position and spatial distribution of aboveground carbon stocks. The results showed that stratification of plot locations based on topography can improve the calibration and application of ACD estimation using airborne LiDAR (R2 = 0.94, RMSE = 5.81 Mg·C·ha−1, BIAS = 0.59. These results strongly suggest that a general LiDAR-based approach can be used for mapping aboveground carbon stocks in western lowland Amazonian forests.

  7. Spatial Analysis of Heterodera glycines Populations in Field Plots

    OpenAIRE

    Francl, L. J.

    1986-01-01

    Spatial heterogeneity in nematode population densities presents an obstacle to the precise determination of infestation levels. Three field plots were intensively sampled for soybean cyst nematode (Heterodera glycines Ich.) cysts before and after spring cultivation to quantify the spatial attributes of the population. Population density strata were detected running parallel to plant rows. Highest population densities before cultivation were found in the plant row and the middle furrow, Popula...

  8. Local extinction synchronizes population dynamics in spatial networks

    OpenAIRE

    Matter, Stephen F.; Roland, Jens

    2009-01-01

    Spatial population theory predicts that synchrony in the dynamics of local populations should decrease as dispersal among populations decreases. Thus, it would be expected that the extinction of local populations and the attendant loss of immigrants to surrounding populations would reduce synchrony. We tested this hypothesis through a large-scale experiment, simulation of the experimental system and general models. Experimental removal of two adjacent subpopulations of the Rocky Mountain Apol...

  9. Extinction rates of established spatial populations

    Science.gov (United States)

    Meerson, Baruch; Sasorov, Pavel V.

    2011-01-01

    This paper deals with extinction of an isolated population caused by intrinsic noise. We model the population dynamics in a “refuge” as a Markov process which involves births and deaths on discrete lattice sites and random migrations between neighboring sites. In extinction scenario I, the zero population size is a repelling fixed point of the on-site deterministic dynamics. In extinction scenario II, the zero population size is an attracting fixed point, corresponding to what is known in ecology as the Allee effect. Assuming a large population size, we develop a WKB (Wentzel-Kramers-Brillouin) approximation to the master equation. The resulting Hamilton’s equations encode the most probable path of the population toward extinction and the mean time to extinction. In the fast-migration limit these equations coincide, up to a canonical transformation, with those obtained, in a different way, by Elgart and Kamenev [Phys. Rev. EPHYADX1539-375510.1103/PhysRevE.70.041106 70, 041106 (2004)]. We classify possible regimes of population extinction with and without an Allee effect and for different types of refuge, and solve several examples analytically and numerically. For a very strong Allee effect, the extinction problem can be mapped into the overdamped limit of the theory of homogeneous nucleation due to Langer [Ann. Phys. (NY)APNYA60003-491610.1016/0003-4916(69)90153-5 54, 258 (1969)]. In this regime, and for very long systems, we predict an optimal refuge size that maximizes the mean time to extinction.

  10. Emergent spatial correlations in stochastically evolving populations

    CERN Document Server

    Grabowski, M; Grabowski, Marek

    1997-01-01

    We study the spatial pattern formation and emerging long range correlations in a model of three species coevolving in space and time according to stochastic contact rules. Analytical results for the pair correlation functions, based on a truncation approximation and supported by computer simulations, reveal emergent strategies of survival for minority agents based on selection of patterns. Minority agents exhibit defensive clustering and cooperative behavior close to phase transitions.

  11. Local extinction synchronizes population dynamics in spatial networks.

    Science.gov (United States)

    Matter, Stephen F; Roland, Jens

    2010-03-01

    Spatial population theory predicts that synchrony in the dynamics of local populations should decrease as dispersal among populations decreases. Thus, it would be expected that the extinction of local populations and the attendant loss of immigrants to surrounding populations would reduce synchrony. We tested this hypothesis through a large-scale experiment, simulation of the experimental system and general models. Experimental removal of two adjacent subpopulations of the Rocky Mountain Apollo butterfly, Parnassius smintheus within a network consisting of 15 other local populations resulted in a decrease in immigration to surrounding populations that was proportional to their connectivity to the removal populations. These populations also showed a significant increase in synchrony during population removal. The spatial extent of the synchrony showed good agreement with the predicted loss of immigrants owing to the removals. Simulation of the Parnassius system showed a similar short-term result and also indicated that permanent loss of populations produces structural changes increasing synchrony. General models indicate that an increase in synchrony following extinction occurs when populations undergoing extinction have different carrying capacities than surrounding populations. The result is not owing to biased migration per se, but rather is because of the number of immigrants relative to the carrying capacity. Synchrony following extinction should be most common for patchy populations, but can occur in any situation where carrying capacities differ. Overall, our results indicate that local extinction can create a positive feedback for extinction risk, increasing the probability of extinction for population networks by synchronizing their dynamics. PMID:19889700

  12. Historically grounded spatial population projections for the continental United States

    International Nuclear Information System (INIS)

    Large-scale spatial population projections are of growing importance to the global change community. Spatial settlement patterns are a key determinant of vulnerability to climate-related hazards as well as to land-use and its consequences for habitat, energy use, and emissions of greenhouse gases and air pollutants. Few projections exist of spatial distribution at national or larger scales, and while recent efforts improve on earlier approaches that simply scaled or extrapolated existing spatial patterns, important methodological shortcomings remain and models have not been calibrated to nor validated against historical trends. Here we present spatially explicit 100-year projections for the continental United States consistent with two different scenarios of possible socio-economic development. The projections are based on a new model that is calibrated to observed changes in regional population distribution since 1950, corrects for distorting effects at borders, and employs a spatial mask for designating protected or uninhabitable land. Using new metrics for comparing spatial outcomes, we find that our projections anticipate more moderate trends in urban expansion and coastal settlement than widely used existing projections. We also find that differences in outcomes across models are much larger than differences across alternative socio-economic scenarios for a given model, emphasizing the importance of better understanding of methods of spatial population projection for improved integrated assessments of social and environmental change. (letter)

  13. Spread of pedigree versus genetic ancestry in spatially distributed populations

    OpenAIRE

    Kelleher, J; Etheridge, AM; Véber, A.; Barton, NH

    2016-01-01

    Ancestral processes are fundamental to modern population genetics and spatial structure has been the subject of intense interest for many years. Despite this interest, almost nothing is known about the distribution of the locations of pedigree or genetic ancestors. Using both spatially continuous and stepping-stone models, we show that the distribution of pedigree ancestors approaches a travelling wave, for which we develop two alternative approximations. The speed and width of the wave are s...

  14. Large-scale spatial population databases in infectious disease research.

    Science.gov (United States)

    Linard, Catherine; Tatem, Andrew J

    2012-01-01

    Modelling studies on the spatial distribution and spread of infectious diseases are becoming increasingly detailed and sophisticated, with global risk mapping and epidemic modelling studies now popular. Yet, in deriving populations at risk of disease estimates, these spatial models must rely on existing global and regional datasets on population distribution, which are often based on outdated and coarse resolution data. Moreover, a variety of different methods have been used to model population distribution at large spatial scales. In this review we describe the main global gridded population datasets that are freely available for health researchers and compare their construction methods, and highlight the uncertainties inherent in these population datasets. We review their application in past studies on disease risk and dynamics, and discuss how the choice of dataset can affect results. Moreover, we highlight how the lack of contemporary, detailed and reliable data on human population distribution in low income countries is proving a barrier to obtaining accurate large-scale estimates of population at risk and constructing reliable models of disease spread, and suggest research directions required to further reduce these barriers. PMID:22433126

  15. Large-scale spatial population databases in infectious disease research

    Directory of Open Access Journals (Sweden)

    Linard Catherine

    2012-03-01

    Full Text Available Abstract Modelling studies on the spatial distribution and spread of infectious diseases are becoming increasingly detailed and sophisticated, with global risk mapping and epidemic modelling studies now popular. Yet, in deriving populations at risk of disease estimates, these spatial models must rely on existing global and regional datasets on population distribution, which are often based on outdated and coarse resolution data. Moreover, a variety of different methods have been used to model population distribution at large spatial scales. In this review we describe the main global gridded population datasets that are freely available for health researchers and compare their construction methods, and highlight the uncertainties inherent in these population datasets. We review their application in past studies on disease risk and dynamics, and discuss how the choice of dataset can affect results. Moreover, we highlight how the lack of contemporary, detailed and reliable data on human population distribution in low income countries is proving a barrier to obtaining accurate large-scale estimates of population at risk and constructing reliable models of disease spread, and suggest research directions required to further reduce these barriers.

  16. Prevalência de cárie dental em uma população de escolares da região amazônica Prevalence of dental caries in a school population of the amazonian region

    Directory of Open Access Journals (Sweden)

    Antonio David Corrêa Normando

    1990-08-01

    Full Text Available Considerando-se a ausência de dados sobre a prevalência de cárie dental em uma população tipicamente amazônida, foi feito um levantamento epidemiológico em 103 escolares na região da Ilha de Sirituba, no Município de Abaetetuba, Estado do Pará, Brasil. O CPOD médio encontrado foi de 6,5 e o ceo de 5,4. Apesar da primitividade do local, o alto índice de cárie pode estar relacionado a diversos fatores, dentre os quais deve ser incluída a influência urbana na alimentação, principalmente pelo açúcar, criando novos hábitos alimentares que alteraram fundamentalmente a dieta da região.In view of the lack of data as to the prevalence of dental caries among typical amazonian populations, the authors carried out an epidemiological study of 103 schoolchildren from Sirituba Island, Abaetetuba, Pará, Brazil. The mean values found for DMFT and deft were 6.5 and 5.4 respectively. Although the region is very primitive, this high prevalence may be linked to several factors, among which is the urban influence, mainly through the use of sugar, on food habits in such a way as fundamentally to alter the diet of the amazonian population.

  17. The mutation-drift balance in spatially structured populations.

    Science.gov (United States)

    Schneider, David M; Martins, Ayana B; de Aguiar, Marcus A M

    2016-08-01

    In finite populations the action of neutral mutations is balanced by genetic drift, leading to a stationary distribution of alleles that displays a transition between two different behaviors. For small mutation rates most individuals will carry the same allele at equilibrium, whereas for high mutation rates of the alleles will be randomly distributed with frequencies close to one half for a biallelic gene. For well-mixed haploid populations the mutation threshold is μc=1/2N, where N is the population size. In this paper we study how spatial structure affects this mutation threshold. Specifically, we study the stationary allele distribution for populations placed on regular networks where connected nodes represent potential mating partners. We show that the mutation threshold is sensitive to spatial structure only if the number of potential mates is very small. In this limit, the mutation threshold decreases substantially, increasing the diversity of the population at considerably low mutation rates. Defining kc as the degree of the network for which the mutation threshold drops to half of its value in well-mixed populations we show that kc grows slowly as a function of the population size, following a power law. Our calculations and simulations are based on the Moran model and on a mapping between the Moran model with mutations and the voter model with opinion makers. PMID:27132184

  18. Estimating the global conservation status of more than 15,000 Amazonian tree species

    DEFF Research Database (Denmark)

    ter Steege, Hans; Pitman, Nigel C. A.; Killeen, Timothy J.;

    2015-01-01

    Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree...

  19. Spatially resolved fish population analysis for designing MPAs

    DEFF Research Database (Denmark)

    Christensen, Asbjørn; Mosegaard, Henrik; Jensen, Henrik

    2009-01-01

    The sandeel population analysis model (SPAM) is presented as a simulation tool for exploring the efficiency of Marine Protected Areas (MPAs) for sandeel stocks. SPAM simulates spatially resolved sandeel population distributions, based on a high-resolution map of all fishery-established sandbank...... habitats for settled sandeels, combined with a life-cycle model for survival, growth, and reproduction, and a three-dimensional hydrodynamic model for describing larval transport between the network of habitats. SPAM couples stock dynamics to ecosystem and anthropogenic forcing via well-defined drivers....... The SPAM framework was tested using ICES statistical rectangle 37F2 as an MPA, and the impact on sandeel populations within the MPA and neighbouring habitats was investigated. Increased larval spillover compensated for lost catches inside the MPA. The temporal and spatial scales of stock response to...

  20. Critical fitness collapse in three-dimensional spatial population genetics

    Science.gov (United States)

    Lavrentovich, Maxim O.

    2015-05-01

    If deleterious mutations near a fitness maximum in a spatially distributed population are sufficiently frequent or detrimental, the population can undergo a fitness collapse, similarly to the Muller's ratchet effect in well-mixed populations. Recent studies of 1D habitats (e.g. the frontier of a 2D range expansion) have shown that the onset of the fitness collapse is described by a directed percolation phase transition with its associated critical exponents. We consider population fitness collapse in 3D range expansions with both inflating and fixed-size frontiers (applicable to, e.g. expanding and treadmilling spherical tumors, respectively). We find that the onset of fitness collapse in these two cases obeys different scaling laws, and that competition between species at the frontier leads to a deviation from directed percolation scaling. As in 2D range expansions, inflating frontiers modify the critical behavior by causally disconnecting well-separated portions of the population.

  1. Hêliconias como alternativa econômica para comunidades amazônicas Heliconias of the Baixo Juruá Extractive Reserve: economical potential for Amazonian traditional population

    Directory of Open Access Journals (Sweden)

    Rafael Arruda

    2008-12-01

    Heliconia genus is one of the colorful groups of tropical forest non-timber plants. However, as an income source, it is unknown to the RESEX communities. We registered 11 species of Heliconia in the Baixo Juruá Extractive Reserve with potential as ornamental plants: H. acuminata, H. densiflora, H. hirsuta, H. lasiorachis, H. stricta, H. chartacea, H. juruana, H. marginata, H. psittacorum, H. spathocircinata and H. tenebrosa. Currently in Brazil, the commercialization of ornamental plants is expanding, but the Amazonian region seems not to be following this trend, demonstrating perhaps lack of political initiative. Even though it causes some impact on fauna an flora, the practice of extractive economy inside the forest reserves in Amazonia helps keep the ecological functions of the forest intact, preventing future losses of regional biodiversity. Additionally, it guarantees the continuity of traditional populations in the natural areas, with direct effect on the local and regional economy.

  2. Estimating the global conservation status of more than 15,000 Amazonian tree species

    Science.gov (United States)

    ter Steege, Hans; Pitman, Nigel C. A.; Killeen, Timothy J.; Laurance, William F.; Peres, Carlos A.; Guevara, Juan Ernesto; Salomão, Rafael P.; Castilho, Carolina V.; Amaral, Iêda Leão; de Almeida Matos, Francisca Dionízia; de Souza Coelho, Luiz; Magnusson, William E.; Phillips, Oliver L.; de Andrade Lima Filho, Diogenes; de Jesus Veiga Carim, Marcelo; Irume, Mariana Victória; Martins, Maria Pires; Molino, Jean-François; Sabatier, Daniel; Wittmann, Florian; López, Dairon Cárdenas; da Silva Guimarães, José Renan; Mendoza, Abel Monteagudo; Vargas, Percy Núñez; Manzatto, Angelo Gilberto; Reis, Neidiane Farias Costa; Terborgh, John; Casula, Katia Regina; Montero, Juan Carlos; Feldpausch, Ted R.; Honorio Coronado, Euridice N.; Montoya, Alvaro Javier Duque; Zartman, Charles Eugene; Mostacedo, Bonifacio; Vasquez, Rodolfo; Assis, Rafael L.; Medeiros, Marcelo Brilhante; Simon, Marcelo Fragomeni; Andrade, Ana; Camargo, José Luís; Laurance, Susan G. W.; Nascimento, Henrique Eduardo Mendonça; Marimon, Beatriz S.; Marimon, Ben-Hur; Costa, Flávia; Targhetta, Natalia; Vieira, Ima Célia Guimarães; Brienen, Roel; Castellanos, Hernán; Duivenvoorden, Joost F.; Mogollón, Hugo F.; Piedade, Maria Teresa Fernandez; Aymard C., Gerardo A.; Comiskey, James A.; Damasco, Gabriel; Dávila, Nállarett; García-Villacorta, Roosevelt; Diaz, Pablo Roberto Stevenson; Vincentini, Alberto; Emilio, Thaise; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Alonso, Alfonso; Dallmeier, Francisco; Ferreira, Leandro Valle; Neill, David; Araujo-Murakami, Alejandro; Arroyo, Luzmila; Carvalho, Fernanda Antunes; Souza, Fernanda Coelho; do Amaral, Dário Dantas; Gribel, Rogerio; Luize, Bruno Garcia; Pansonato, Marcelo Petrati; Venticinque, Eduardo; Fine, Paul; Toledo, Marisol; Baraloto, Chris; Cerón, Carlos; Engel, Julien; Henkel, Terry W.; Jimenez, Eliana M.; Maas, Paul; Mora, Maria Cristina Peñuela; Petronelli, Pascal; Revilla, Juan David Cardenas; Silveira, Marcos; Stropp, Juliana; Thomas-Caesar, Raquel; Baker, Tim R.; Daly, Doug; Paredes, Marcos Ríos; da Silva, Naara Ferreira; Fuentes, Alfredo; Jørgensen, Peter Møller; Schöngart, Jochen; Silman, Miles R.; Arboleda, Nicolás Castaño; Cintra, Bruno Barçante Ladvocat; Valverde, Fernando Cornejo; Di Fiore, Anthony; Phillips, Juan Fernando; van Andel, Tinde R.; von Hildebrand, Patricio; Barbosa, Edelcilio Marques; de Matos Bonates, Luiz Carlos; de Castro, Deborah; de Sousa Farias, Emanuelle; Gonzales, Therany; Guillaumet, Jean-Louis; Hoffman, Bruce; Malhi, Yadvinder; de Andrade Miranda, Ires Paula; Prieto, Adriana; Rudas, Agustín; Ruschell, Ademir R.; Silva, Natalino; Vela, César I. A.; Vos, Vincent A.; Zent, Eglée L.; Zent, Stanford; Cano, Angela; Nascimento, Marcelo Trindade; Oliveira, Alexandre A.; Ramirez-Angulo, Hirma; Ramos, José Ferreira; Sierra, Rodrigo; Tirado, Milton; Medina, Maria Natalia Umaña; van der Heijden, Geertje; Torre, Emilio Vilanova; Vriesendorp, Corine; Wang, Ophelia; Young, Kenneth R.; Baider, Claudia; Balslev, Henrik; de Castro, Natalia; Farfan-Rios, William; Ferreira, Cid; Mendoza, Casimiro; Mesones, Italo; Torres-Lezama, Armando; Giraldo, Ligia Estela Urrego; Villarroel, Daniel; Zagt, Roderick; Alexiades, Miguel N.; Garcia-Cabrera, Karina; Hernandez, Lionel; Huamantupa-Chuquimaco, Isau; Milliken, William; Cuenca, Walter Palacios; Pansini, Susamar; Pauletto, Daniela; Arevalo, Freddy Ramirez; Sampaio, Adeilza Felipe; Valderrama Sandoval, Elvis H.; Gamarra, Luis Valenzuela

    2015-01-01

    Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened plant species on Earth by 22%. We show that the trends observed in Amazonia apply to trees throughout the tropics, and we predict that most of the world’s >40,000 tropical tree species now qualify as globally threatened. A gap analysis suggests that existing Amazonian protected areas and indigenous territories will protect viable populations of most threatened species if these areas suffer no further degradation, highlighting the key roles that protected areas, indigenous peoples, and improved governance can play in preventing large-scale extinctions in the tropics in this century. PMID:26702442

  3. Estimating the global conservation status of more than 15,000 Amazonian tree species.

    Science.gov (United States)

    Ter Steege, Hans; Pitman, Nigel C A; Killeen, Timothy J; Laurance, William F; Peres, Carlos A; Guevara, Juan Ernesto; Salomão, Rafael P; Castilho, Carolina V; Amaral, Iêda Leão; de Almeida Matos, Francisca Dionízia; de Souza Coelho, Luiz; Magnusson, William E; Phillips, Oliver L; de Andrade Lima Filho, Diogenes; de Jesus Veiga Carim, Marcelo; Irume, Mariana Victória; Martins, Maria Pires; Molino, Jean-François; Sabatier, Daniel; Wittmann, Florian; López, Dairon Cárdenas; da Silva Guimarães, José Renan; Mendoza, Abel Monteagudo; Vargas, Percy Núñez; Manzatto, Angelo Gilberto; Reis, Neidiane Farias Costa; Terborgh, John; Casula, Katia Regina; Montero, Juan Carlos; Feldpausch, Ted R; Honorio Coronado, Euridice N; Montoya, Alvaro Javier Duque; Zartman, Charles Eugene; Mostacedo, Bonifacio; Vasquez, Rodolfo; Assis, Rafael L; Medeiros, Marcelo Brilhante; Simon, Marcelo Fragomeni; Andrade, Ana; Camargo, José Luís; Laurance, Susan G W; Nascimento, Henrique Eduardo Mendonça; Marimon, Beatriz S; Marimon, Ben-Hur; Costa, Flávia; Targhetta, Natalia; Vieira, Ima Célia Guimarães; Brienen, Roel; Castellanos, Hernán; Duivenvoorden, Joost F; Mogollón, Hugo F; Piedade, Maria Teresa Fernandez; Aymard C, Gerardo A; Comiskey, James A; Damasco, Gabriel; Dávila, Nállarett; García-Villacorta, Roosevelt; Diaz, Pablo Roberto Stevenson; Vincentini, Alberto; Emilio, Thaise; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Alonso, Alfonso; Dallmeier, Francisco; Ferreira, Leandro Valle; Neill, David; Araujo-Murakami, Alejandro; Arroyo, Luzmila; Carvalho, Fernanda Antunes; Souza, Fernanda Coelho; do Amaral, Dário Dantas; Gribel, Rogerio; Luize, Bruno Garcia; Pansonato, Marcelo Petrati; Venticinque, Eduardo; Fine, Paul; Toledo, Marisol; Baraloto, Chris; Cerón, Carlos; Engel, Julien; Henkel, Terry W; Jimenez, Eliana M; Maas, Paul; Mora, Maria Cristina Peñuela; Petronelli, Pascal; Revilla, Juan David Cardenas; Silveira, Marcos; Stropp, Juliana; Thomas-Caesar, Raquel; Baker, Tim R; Daly, Doug; Paredes, Marcos Ríos; da Silva, Naara Ferreira; Fuentes, Alfredo; Jørgensen, Peter Møller; Schöngart, Jochen; Silman, Miles R; Arboleda, Nicolás Castaño; Cintra, Bruno Barçante Ladvocat; Valverde, Fernando Cornejo; Di Fiore, Anthony; Phillips, Juan Fernando; van Andel, Tinde R; von Hildebrand, Patricio; Barbosa, Edelcilio Marques; de Matos Bonates, Luiz Carlos; de Castro, Deborah; de Sousa Farias, Emanuelle; Gonzales, Therany; Guillaumet, Jean-Louis; Hoffman, Bruce; Malhi, Yadvinder; de Andrade Miranda, Ires Paula; Prieto, Adriana; Rudas, Agustín; Ruschell, Ademir R; Silva, Natalino; Vela, César I A; Vos, Vincent A; Zent, Eglée L; Zent, Stanford; Cano, Angela; Nascimento, Marcelo Trindade; Oliveira, Alexandre A; Ramirez-Angulo, Hirma; Ramos, José Ferreira; Sierra, Rodrigo; Tirado, Milton; Medina, Maria Natalia Umaña; van der Heijden, Geertje; Torre, Emilio Vilanova; Vriesendorp, Corine; Wang, Ophelia; Young, Kenneth R; Baider, Claudia; Balslev, Henrik; de Castro, Natalia; Farfan-Rios, William; Ferreira, Cid; Mendoza, Casimiro; Mesones, Italo; Torres-Lezama, Armando; Giraldo, Ligia Estela Urrego; Villarroel, Daniel; Zagt, Roderick; Alexiades, Miguel N; Garcia-Cabrera, Karina; Hernandez, Lionel; Huamantupa-Chuquimaco, Isau; Milliken, William; Cuenca, Walter Palacios; Pansini, Susamar; Pauletto, Daniela; Arevalo, Freddy Ramirez; Sampaio, Adeilza Felipe; Valderrama Sandoval, Elvis H; Gamarra, Luis Valenzuela

    2015-11-01

    Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened plant species on Earth by 22%. We show that the trends observed in Amazonia apply to trees throughout the tropics, and we predict that most of the world's >40,000 tropical tree species now qualify as globally threatened. A gap analysis suggests that existing Amazonian protected areas and indigenous territories will protect viable populations of most threatened species if these areas suffer no further degradation, highlighting the key roles that protected areas, indigenous peoples, and improved governance can play in preventing large-scale extinctions in the tropics in this century. PMID:26702442

  4. Spatial and temporal dynamics of infected populations: the Mexican epidemic

    CERN Document Server

    Rodriguez-Meza, Mario A

    2012-01-01

    Recently the A/H1N1-2009 virus pandemic appeared in Mexico and in other nations. We present a study of this pandemic in the Mexican case using the SIR model to describe epidemics. This model is one of the simplest models but it has been a successful description of some epidemics of closed populations. We consider the data for the Mexican case and use the SIR model to make some predictions. Then, we generalize the SIR model in order to describe the spatial dynamics of the disease. We make a study of the spatial and temporal spread of the infected population with model parameters that are consistent with temporal SIR model parameters obtained by fitting to the Mexican case.

  5. Optimal exploitation of spatially distributed trophic resources and population stability

    Science.gov (United States)

    Basset, A.; Fedele, M.; DeAngelis, D.L.

    2002-01-01

    The relationships between optimal foraging of individuals and population stability are addressed by testing, with a spatially explicit model, the effect of patch departure behaviour on individual energetics and population stability. A factorial experimental design was used to analyse the relevance of the behavioural factor in relation to three factors that are known to affect individual energetics; i.e. resource growth rate (RGR), assimilation efficiency (AE), and body size of individuals. The factorial combination of these factors produced 432 cases, and 1000 replicate simulations were run for each case. Net energy intake rates of the modelled consumers increased with increasing RGR, consumer AE, and consumer body size, as expected. Moreover, through their patch departure behaviour, by selecting the resource level at which they departed from the patch, individuals managed to substantially increase their net energy intake rates. Population stability was also affected by the behavioural factors and by the other factors, but with highly non-linear responses. Whenever resources were limiting for the consumers because of low RGR, large individual body size or low AE, population density at the equilibrium was directly related to the patch departure behaviour; on the other hand, optimal patch departure behaviour, which maximised the net energy intake at the individual level, had a negative influence on population stability whenever resource availability was high for the consumers. The consumer growth rate (r) and numerical dynamics, as well as the spatial and temporal fluctuations of resource density, which were the proximate causes of population stability or instability, were affected by the behavioural factor as strongly or even more strongly than by the others factors considered here. Therefore, patch departure behaviour can act as a feedback control of individual energetics, allowing consumers to optimise a potential trade-off between short-term individual fitness

  6. Stochastic population oscillations in spatial predator-prey models

    Energy Technology Data Exchange (ETDEWEB)

    Taeuber, Uwe C, E-mail: tauber@vt.edu [Department of Physics, Virginia Tech, Blacksburg, VA 24061-0435 (United States)

    2011-09-15

    It is well-established that including spatial structure and stochastic noise in models for predator-prey interactions invalidates the classical deterministic Lotka-Volterra picture of neutral population cycles. In contrast, stochastic models yield long-lived, but ultimately decaying erratic population oscillations, which can be understood through a resonant amplification mechanism for density fluctuations. In Monte Carlo simulations of spatial stochastic predator-prey systems, one observes striking complex spatio-temporal structures. These spreading activity fronts induce persistent correlations between predators and prey. In the presence of local particle density restrictions (finite prey carrying capacity), there exists an extinction threshold for the predator population. The accompanying continuous non-equilibrium phase transition is governed by the directed-percolation universality class. We employ field-theoretic methods based on the Doi-Peliti representation of the master equation for stochastic particle interaction models to (i) map the ensuing action in the vicinity of the absorbing state phase transition to Reggeon field theory, and (ii) to quantitatively address fluctuation-induced renormalizations of the population oscillation frequency, damping, and diffusion coefficients in the species coexistence phase.

  7. The effects of spatial population dataset choice on estimates of population at risk of disease

    Directory of Open Access Journals (Sweden)

    Gething Peter W

    2011-02-01

    Full Text Available Abstract Background The spatial modeling of infectious disease distributions and dynamics is increasingly being undertaken for health services planning and disease control monitoring, implementation, and evaluation. Where risks are heterogeneous in space or dependent on person-to-person transmission, spatial data on human population distributions are required to estimate infectious disease risks, burdens, and dynamics. Several different modeled human population distribution datasets are available and widely used, but the disparities among them and the implications for enumerating disease burdens and populations at risk have not been considered systematically. Here, we quantify some of these effects using global estimates of populations at risk (PAR of P. falciparum malaria as an example. Methods The recent construction of a global map of P. falciparum malaria endemicity enabled the testing of different gridded population datasets for providing estimates of PAR by endemicity class. The estimated population numbers within each class were calculated for each country using four different global gridded human population datasets: GRUMP (~1 km spatial resolution, LandScan (~1 km, UNEP Global Population Databases (~5 km, and GPW3 (~5 km. More detailed assessments of PAR variation and accuracy were conducted for three African countries where census data were available at a higher administrative-unit level than used by any of the four gridded population datasets. Results The estimates of PAR based on the datasets varied by more than 10 million people for some countries, even accounting for the fact that estimates of population totals made by different agencies are used to correct national totals in these datasets and can vary by more than 5% for many low-income countries. In many cases, these variations in PAR estimates comprised more than 10% of the total national population. The detailed country-level assessments suggested that none of the datasets was

  8. Visualizing spatial population structure with estimated effective migration surfaces.

    Science.gov (United States)

    Petkova, Desislava; Novembre, John; Stephens, Matthew

    2016-01-01

    Genetic data often exhibit patterns broadly consistent with 'isolation by distance'-a phenomenon where genetic similarity decays with geographic distance. In a heterogeneous habitat, this may occur more quickly in some regions than in others: for example, barriers to gene flow can accelerate differentiation between neighboring groups. We use the concept of 'effective migration' to model the relationship between genetics and geography. In this paradigm, effective migration is low in regions where genetic similarity decays quickly. We present a method to visualize variation in effective migration across a habitat from geographically indexed genetic data. Our approach uses a population genetic model to relate effective migration rates to expected genetic dissimilarities. We illustrate its potential and limitations using simulations and data from elephant, human and Arabidopsis thaliana populations. The resulting visualizations highlight important spatial features of population structure that are difficult to discern using existing methods for summarizing genetic variation. PMID:26642242

  9. Assessment of Spatial Interpolation Methods to Map the Bathymetry of an Amazonian Hydroelectric Reservoir to Aid in Decision Making for Water Management

    Directory of Open Access Journals (Sweden)

    Marcelo Curtarelli

    2015-02-01

    Full Text Available The generation of reliable information for improving the understanding of hydroelectric reservoir dynamics is fundamental for guiding decision-makers to implement best management practices. In this way, we assessed the performance of different interpolation algorithms to map the bathymetry of the Tucuruí hydroelectric reservoir, located in the Brazilian Amazon, as an aid to manage and operate Amazonian reservoirs. We evaluated three different deterministic and one geostatistical algorithms. The performance of the algorithms was assessed through cross-validation and Monte Carlo Simulation. Finally, operational information was derived from the bathymetric grid with the best performance. The results showed that all interpolation methods were able to map important bathymetric features. The best performance was obtained with the geostatistical method (RMSE = 0.92 m. The information derived from the bathymetric map (e.g., the level-area and level-volume diagram and the three-dimensional grid will allow for optimization of operational monitoring of the Tucuruí hydroelectric reservoir as well as the development of three-dimensional modeling studies.

  10. Extinction risks of Amazonian plant species.

    Science.gov (United States)

    Feeley, Kenneth J; Silman, Miles R

    2009-07-28

    Estimates of the number, and preferably the identity, of species that will be threatened by land-use change and habitat loss are an invaluable tool for setting conservation priorities. Here, we use collections data and ecoregion maps to generate spatially explicit distributions for more than 40,000 vascular plant species from the Amazon basin (representing more than 80% of the estimated Amazonian plant diversity). Using the distribution maps, we then estimate the rates of habitat loss and associated extinction probabilities due to land-use changes as modeled under 2 disturbance scenarios. We predict that by 2050, human land-use practices will have reduced the habitat available to Amazonian plant species by approximately 12-24%, resulting in 5-9% of species becoming "committed to extinction," significantly fewer than other recent estimates. Contrary to previous studies, we find that the primary determinant of habitat loss and extinction risk is not the size of a species' range, but rather its location. The resulting extinction risk estimates are a valuable conservation tool because they indicate not only the total percentage of Amazonian plant species threatened with extinction but also the degree to which individual species and habitats will be affected by current and future land-use changes. PMID:19617552

  11. Local-scale spatial variation in diversity of social wasps in an Amazonian rain forest in Caxiuanã, Pará, Brazil (Hymenoptera, Vespidae, Polistinae)

    OpenAIRE

    Orlando Tobias Silveira; Suzanna de Sousa Silva; Jorge Luis Gavina Pereira; Ingrid da Silva Tavares

    2012-01-01

    Polistine wasps are important in Neotropical ecosystems due to their ubiquity and diversity. Inventories have not adequately considered spatial attributes of collected specimens. Spatial data on biodiversity are important for study and mitigation of anthropogenic impacts over natural ecosystems and for protecting species. We described and analyzed local-scale spatial patterns of collecting records of wasp species, as well as spatial variation of diversity descriptors in a 2500-hectare area of...

  12. Spread of pedigree versus genetic ancestry in spatially distributed populations.

    Science.gov (United States)

    Kelleher, J; Etheridge, A M; Véber, A; Barton, N H

    2016-04-01

    Ancestral processes are fundamental to modern population genetics and spatial structure has been the subject of intense interest for many years. Despite this interest, almost nothing is known about the distribution of the locations of pedigree or genetic ancestors. Using both spatially continuous and stepping-stone models, we show that the distribution of pedigree ancestors approaches a travelling wave, for which we develop two alternative approximations. The speed and width of the wave are sensitive to the local details of the model. After a short time, genetic ancestors spread far more slowly than pedigree ancestors, ultimately diffusing out with radius ∼t rather than spreading at constant speed. In contrast to the wave of pedigree ancestors, the spread of genetic ancestry is insensitive to the local details of the models. PMID:26546979

  13. Spatial structure and chaos in insect population dynamics

    Science.gov (United States)

    Hassell, Michael P.; Comins, Hugh N.; Mayt, Robert M.

    1991-09-01

    MOST environments are spatially subdivided, or patchy, and there has been much interest in the relationship between the dynamics of populations at the local and regional (metapopulation) scales1. Here we study mathematical models for host-parasitoid interactions, where in each generation specified fractions (µN and µp, respectively) of the host and parasitoid subpopulations in each patch move to adjacent patches; in most previous work, the movement is not localized but is to any other patch2. These simple and biologically sensible models with limited diffusive dispersal exhibit a remarkable range of dynamic behaviour: the density of the host and parasitoid subpopulations in a two-dimensional array of patches may exhibit complex patterns of spiral waves or spatially chaotic variation, they may show static 'crystal lattice' patterns, or they may become extinct. This range of behaviour is obtained with the local dynamics being deterministically unstable, with a constant host reproductive rate and no density dependence in the movement patterns. The dynamics depend on the host reproductive rate, and on the values of the parameters µN and µp. The results are relatively insensitive to the details of the interactions; we get essentially the same results from the mathematically-explicit Nicholon-Bailey model of host-parasitoid interactions, and from a very general 'cellular automaton' model in which only qualitative rules are specified. We conclude that local movement in a patchy environment can help otherwise unstable host and parasitoid populations to persist together, but that the deterministically generated spatial patterns in population density can be exceedingly complex (and sometimes indistinguishable from random environmental fluctuations).

  14. Spatio-Temporal Population Density and Spatial Dynamic Spectrum Allocation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A realistic population density distribution scenario in conjunction with the spatial dynamic spectrum allocation (DSA) is taken into account to mitigate the spectrum wastage in terms of extra guard bands. For the insertion of the extra guard bands, an efficient strategy based on self-assessment is applied to each victim cell individually and independently. Consequently, it is no more required to spread the extra guard band over the whole DSA region. Simulation results show an improvement of 3% -4% in percentage of satisfied users for Universal Mobile Telecommunications System ( UMTS ) network and 4% -5% for Digital Video Broadcasting Terrestrial (DVB-T) network.

  15. Origin and Domestication of Native Amazonian Crops

    Directory of Open Access Journals (Sweden)

    Doriane Picanço-Rodrigues

    2010-01-01

    Full Text Available Molecular analyses are providing new elements to decipher the origin, domestication and dispersal of native Amazonian crops in an expanding archaeological context. Solid molecular data are available for manioc (Manihot esculenta, cacao (Theobroma cacao, pineapple (Ananas comosus, peach palm (Bactris gasipaes and guaraná (Paullinia cupana, while hot peppers (Capsicum spp., inga (Inga edulis, Brazil nut (Bertholletia excelsa and cupuassu (Theobroma grandiflorum are being studied. Emergent patterns include the relationships among domestication, antiquity (terminal Pleistocene to early Holocene, origin in the periphery, ample pre-Columbian dispersal and clear phylogeographic population structure for manioc, pineapple, peach palm and, perhaps, Capsicum peppers. Cacao represents the special case of an Amazonian species possibly brought into domestication in Mesoamerica, but close scrutiny of molecular data suggests that it may also have some incipiently domesticated populations in Amazonia. Another pattern includes the relationships among species with incipiently domesticated populations or very recently domesticated populations, rapid pre- or post-conquest dispersal and lack of phylogeographic population structure, e.g., Brazil nut, cupuassu and guaraná. These patterns contrast the peripheral origin of most species with domesticated populations with the subsequent concentration of their genetic resources in the center of the basin, along the major white water rivers where high pre-conquest population densities developed. Additional molecular genetic analyses on these and other species will allow better examination of these processes and will enable us to relate them to other historical ecological patterns in Amazonia.

  16. Spatial distribution and ethnic homogenization of population in Serbia

    Directory of Open Access Journals (Sweden)

    Raduški Nada

    2011-01-01

    Full Text Available In the article is going to presented the ethnic picture of the population of the Serbia and the ethnodemographic changes in period 1991-2002, caused by migration, natural movement, changed declaration on national affiliation, as well as some political and socio-economic factors. Ethnocentric migrations (voluntary and forced primarily influenced on the change of ethnic structure of the Serbia, in the sense of creating nationally more homogeneous region, having in mind the national structure of refugee- population. On the other side, the emigration of some other nationalities which migrated to their mother countries due to political and economic reasons influenced on the ethnic structure, too. Spatial distribution of population according to nationality is an important aspect of demographic development conditioned primarily by ethnically differentiated natural growth and migrations, but also with the impact of numerous other factors. In Serbia is present an exceptional concentration and homogenization of population of certain nationalities. Due to specific territorial distribution and ethnic domination of relevant national minorities in border parts of the country, the question of their status and territorial-political organization gives special severity and significance to the minority question in Serbia. Having in mind that Serbia is a multiethnic and multiconfessional state, the protection of minorities rights and good inter-ethnic relations are necessary for peace, stability and democratic development of the Serbia and the Balkans region.

  17. Evolutionary dynamics of collective action in spatially structured populations.

    Science.gov (United States)

    Peña, Jorge; Nöldeke, Georg; Lehmann, Laurent

    2015-10-01

    Many models proposed to study the evolution of collective action rely on a formalism that represents social interactions as n-player games between individuals adopting discrete actions such as cooperate and defect. Despite the importance of spatial structure in biological collective action, the analysis of n-player games games in spatially structured populations has so far proved elusive. We address this problem by considering mixed strategies and by integrating discrete-action n-player games into the direct fitness approach of social evolution theory. This allows to conveniently identify convergence stable strategies and to capture the effect of population structure by a single structure coefficient, namely, the pairwise (scaled) relatedness among interacting individuals. As an application, we use our mathematical framework to investigate collective action problems associated with the provision of three different kinds of collective goods, paradigmatic of a vast array of helping traits in nature: "public goods" (both providers and shirkers can use the good, e.g., alarm calls), "club goods" (only providers can use the good, e.g., participation in collective hunting), and "charity goods" (only shirkers can use the good, e.g., altruistic sacrifice). We show that relatedness promotes the evolution of collective action in different ways depending on the kind of collective good and its economies of scale. Our findings highlight the importance of explicitly accounting for relatedness, the kind of collective good, and the economies of scale in theoretical and empirical studies of the evolution of collective action. PMID:26151588

  18. Large-scale degradation of Amazonian freshwater ecosystems.

    Science.gov (United States)

    Castello, Leandro; Macedo, Marcia N

    2016-03-01

    Hydrological connectivity regulates the structure and function of Amazonian freshwater ecosystems and the provisioning of services that sustain local populations. This connectivity is increasingly being disrupted by the construction of dams, mining, land-cover changes, and global climate change. This review analyzes these drivers of degradation, evaluates their impacts on hydrological connectivity, and identifies policy deficiencies that hinder freshwater ecosystem protection. There are 154 large hydroelectric dams in operation today, and 21 dams under construction. The current trajectory of dam construction will leave only three free-flowing tributaries in the next few decades if all 277 planned dams are completed. Land-cover changes driven by mining, dam and road construction, agriculture and cattle ranching have already affected ~20% of the Basin and up to ~50% of riparian forests in some regions. Global climate change will likely exacerbate these impacts by creating warmer and dryer conditions, with less predictable rainfall and more extreme events (e.g., droughts and floods). The resulting hydrological alterations are rapidly degrading freshwater ecosystems, both independently and via complex feedbacks and synergistic interactions. The ecosystem impacts include biodiversity loss, warmer stream temperatures, stronger and more frequent floodplain fires, and changes to biogeochemical cycles, transport of organic and inorganic materials, and freshwater community structure and function. The impacts also include reductions in water quality, fish yields, and availability of water for navigation, power generation, and human use. This degradation of Amazonian freshwater ecosystems cannot be curbed presently because existing policies are inconsistent across the Basin, ignore cumulative effects, and overlook the hydrological connectivity of freshwater ecosystems. Maintaining the integrity of these freshwater ecosystems requires a basinwide research and policy framework

  19. Toward Synthetic Spatial Patterns in Engineered Cell Populations with Chemotaxis.

    Science.gov (United States)

    Duran-Nebreda, Salva; Solé, Ricard V

    2016-07-15

    A major force shaping form and patterns in biology is based in the presence of amplification mechanisms able to generate ordered, large-scale spatial structures out of local interactions and random initial conditions. Turing patterns are one of the best known candidates for such ordering dynamics, and their existence has been proven in both chemical and physical systems. Their relevance in biology, although strongly supported by indirect evidence, is still under discussion. Extensive modeling approaches have stemmed from Turing's pioneering ideas, but further confirmation from experimental biology is required. An alternative possibility is to engineer cells so that self-organized patterns emerge from local communication. Here we propose a potential synthetic design based on the interaction between population density and a diffusing signal, including also directed motion in the form of chemotaxis. The feasibility of engineering such a system and its implications for developmental biology are also assessed. PMID:27009520

  20. Local-scale spatial variation in diversity of social wasps in an Amazonian rain forest in Caxiuanã, Pará, Brazil (Hymenoptera, Vespidae, Polistinae

    Directory of Open Access Journals (Sweden)

    Orlando Tobias Silveira

    2012-09-01

    Full Text Available Polistine wasps are important in Neotropical ecosystems due to their ubiquity and diversity. Inventories have not adequately considered spatial attributes of collected specimens. Spatial data on biodiversity are important for study and mitigation of anthropogenic impacts over natural ecosystems and for protecting species. We described and analyzed local-scale spatial patterns of collecting records of wasp species, as well as spatial variation of diversity descriptors in a 2500-hectare area of an Amazon forest in Brazil. Rare species comprised the largest fraction of the fauna. Close range spatial effects were detected for most of the more common species, with clustering of presence-data at short distances. Larger spatial lag effects could also be identified in some species, constituting probably cases of exogenous autocorrelation and candidates for explanations based on environmental factors. In a few cases, significant or near significant correlations were found between five species (of Agelaia, Angiopolybia, and Mischocyttarus and three studied environmental variables: distance to nearest stream, terrain altitude, and the type of forest canopy. However, association between these factors and biodiversity variables were generally low. When used as predictors of polistine richness in a linear multiple regression, only the coefficient for the forest canopy variable resulted significant. Some level of prediction of wasp diversity variables can be attained based on environmental variables, especially vegetation structure. Large-scale landscape and regional studies should be scheduled to address this issue.

  1. Estimating the global conservation status of more than 15,000 Amazonian tree species

    OpenAIRE

    H. ter Steege; Pitman, NC; Killeen, TJ; Laurance, WF; Peres, CA; Guevara, JE; Salomão, RP; Castilho, CV; Amaral, IL; de Almeida Matos, FD; de Souza Coelho, L; Magnusson, WE; Phillips, OL; de Andrade Lima Filho, D; de Jesus Veiga Carim, M

    2015-01-01

    Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened ...

  2. Estimating the global conservation status of more than 15,000 Amazonian tree species.

    OpenAIRE

    H. ter Steege; Pitman, NC; Killeen, TJ; Laurance, WF; Peres, CA; Guevara, JE; Salomão, RP; Castilho, CV; Amaral, IL; de Almeida Matos, FD; de Souza Coelho, L; Magnusson, WE; Phillips, OL; de Andrade Lima Filho, D; de Jesus Veiga Carim, M

    2015-01-01

    Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened ...

  3. Spatial Changes and Population Movements on the Albanian Coastline

    Science.gov (United States)

    Kanjir, U.; Gregorič Bon, N.

    2016-06-01

    The last decade has seen a large increase in construction along the southern Albanian coastline, mainly in the rise of large tourist complexes comprising hotels, apartment houses, touristic villages, and so on. These constructions rarely follow urban planning and not only change its landscape but also often threaten the ecological value of the coastal zone. The uncontrolled and devastating construction along the coast has been accompanied by coastal erosion caused by the sea with the intensity up to 50 cm/year. This paper investigates the environmental change monitoring on the Albanian Riviera by analysing optical remote sensing data (Landsat 5 and 8) in the period between 1984 and 2015. The image analysis results grounded on the change vector analysis indicate coastal morphology changes and land cover changes in the coastal environment, which appear mostly due to erosion in river delta and urban growth. Apart from identifying both phenomena through time, the objective of this study is to show that these landscape changes in fact correlate with the population migration as well as to explain why and the extent to which Albania is one of the most migratory countries in Europe. Based on the multidisciplinary research, which combines anthropological method with spatial analysis, this presentation anticipates future changes in this area. It argues that movements of both people and in landscape formations strongly influence each other, constituting a closely corresponding relationship.

  4. Predicting the spatial distribution of population based on impervious surface maps and modeled land use change

    OpenAIRE

    Cornet, Yves; Binard, Marc; Ledant, Martin; Van der Kwast, Hans; Van de Voorde, Tim; Canters, Frank

    2012-01-01

    Land use and changes in the spatial distribution of population are spatially and temporally linked and have an obvious impact on the urban environment. For instance, they influence the mobility and accessibility and play an important role in waste water management. This forecasting of the spatial distribution of population is thus a critical issue in planning. In order to allow this forecasting we have adjusted a multiple regression model to estimate the population distribution in function of...

  5. Spatial synchrony in population dynamics: The effects of demographic stochasticity and density regulation with a spatial scale.

    Science.gov (United States)

    Engen, Steinar; Sæther, Bernt-Erik

    2016-04-01

    We generalize a previous simple result by Lande et al. (1999) on how spatial autocorrelated noise, dispersal rate and distance as well as strength of density regulation determine the spatial scale of synchrony in population density. It is shown how demographic noise can be incorporated, what effect it has on variance and spatial scale of synchrony, and how it interacts with the point process for locations of individuals under random sampling. Although the effect of demographic noise is a rather complex interaction with environmental noise, migration and density regulation, its effect on population fluctuations and scale of synchrony can be presented in a transparent way. This is achieved by defining a characteristic area dependent on demographic and environmental variances as well as population density, and subsequently using this area to define a spatial demographic coefficient. The demographic noise acts through this coefficient on the spatial synchrony, which may increase or decrease with increasing demographic noise depending on other parameters. A second generalization yields the modeling of density regulation taking into account that regulation at a given location does not only depend on the density at that site but also on densities in the whole territory or home range of individuals. It is shown that such density regulation with a spatial scale reduces the scale of synchrony in population fluctuations relative to the simpler model with density regulation at each location determined only by the local point density, and may even generate negative spatial autocorrelations. PMID:26852669

  6. Biochemical parameters of the amazonian manatee´s blood (Trichechus inunguis, Mammalia: Sirenia)

    OpenAIRE

    Elton Pinto Colares; Ioni Gonçalves Colares; Ary Domingos do Amaral

    2011-01-01

    The blood biochemical and hematological parameters make possible to acquire information about the physiological situation of animals or their population, permitting in this way the diagnosis of possible pathologies. The objective of this work was to check the normal values of some biochemical parameters of the captive Amazonian manatee´s blood and compare them with other animals´. In this study, 10 Amazonian manatees kept in captivity in the Instituto Nacional de Pesquisas da Amazônia, being ...

  7. Extremely long-distance seed dispersal by an overfished Amazonian frugivore

    OpenAIRE

    Anderson, Jill T.; Nuttle, Tim; Saldaña Rojas, Joe S.; Pendergast, Thomas H.; Flecker, Alexander S.

    2011-01-01

    Throughout Amazonia, overfishing has decimated populations of fruit-eating fishes, especially the large-bodied characid, Colossoma macropomum. During lengthy annual floods, frugivorous fishes enter vast Amazonian floodplains, consume massive quantities of fallen fruits and egest viable seeds. Many tree and liana species are clearly specialized for icthyochory, and seed dispersal by fish may be crucial for the maintenance of Amazonian wetland forests. Unlike frugivorous mammals and birds, litt...

  8. Genetic Drift Suppresses Bacterial Conjugation in Spatially Structured Populations

    Science.gov (United States)

    Freese, Peter D.; Korolev, Kirill S.; Jiménez, José I.; Chen, Irene A.

    2014-02-01

    Conjugation is the primary mechanism of horizontal gene transfer that spreads antibiotic resistance among bacteria. Although conjugation normally occurs in surface-associated growth (e.g., biofilms), it has been traditionally studied in well-mixed liquid cultures lacking spatial structure, which is known to affect many evolutionary and ecological processes. Here we visualize spatial patterns of gene transfer mediated by F plasmid conjugation in a colony of Escherichia coli growing on solid agar, and we develop a quantitative understanding by spatial extension of traditional mass-action models. We found that spatial structure suppresses conjugation in surface-associated growth because strong genetic drift leads to spatial isolation of donor and recipient cells, restricting conjugation to rare boundaries between donor and recipient strains. These results suggest that ecological strategies, such as enforcement of spatial structure and enhancement of genetic drift, could complement molecular strategies in slowing the spread of antibiotic resistance genes.

  9. The discovery of the Amazonian tree flora with an updated checklist of all known tree taxa

    Science.gov (United States)

    ter Steege, Hans; Vaessen, Rens W.; Cárdenas-López, Dairon; Sabatier, Daniel; Antonelli, Alexandre; de Oliveira, Sylvia Mota; Pitman, Nigel C. A.; Jørgensen, Peter Møller; Salomão, Rafael P.

    2016-01-01

    Amazonia is the most biodiverse rainforest on Earth, and the debate over how many tree species grow there remains contentious. Here we provide a checklist of all tree species collected to date, and describe spatial and temporal trends in data accumulation. We report 530,025 unique collections of trees in Amazonia, dating between 1707 and 2015, for a total of 11,676 species in 1225 genera and 140 families. These figures support recent estimates of 16,000 total Amazonian tree species based on ecological plot data from the Amazonian Tree Diversity Network. Botanical collection in Amazonia is characterized by three major peaks, centred around 1840, 1920, and 1980, which are associated with flora projects and the establishment of inventory plots. Most collections were made in the 20th century. The number of collections has increased exponentially, but shows a slowdown in the last two decades. We find that a species’ range size is a better predictor of the number of times it has been collected than the species’ estimated basin-wide population size. Finding, describing, and documenting the distribution of the remaining species will require coordinated efforts at under-collected sites. PMID:27406027

  10. The discovery of the Amazonian tree flora with an updated checklist of all known tree taxa.

    Science.gov (United States)

    Ter Steege, Hans; Vaessen, Rens W; Cárdenas-López, Dairon; Sabatier, Daniel; Antonelli, Alexandre; de Oliveira, Sylvia Mota; Pitman, Nigel C A; Jørgensen, Peter Møller; Salomão, Rafael P

    2016-01-01

    Amazonia is the most biodiverse rainforest on Earth, and the debate over how many tree species grow there remains contentious. Here we provide a checklist of all tree species collected to date, and describe spatial and temporal trends in data accumulation. We report 530,025 unique collections of trees in Amazonia, dating between 1707 and 2015, for a total of 11,676 species in 1225 genera and 140 families. These figures support recent estimates of 16,000 total Amazonian tree species based on ecological plot data from the Amazonian Tree Diversity Network. Botanical collection in Amazonia is characterized by three major peaks, centred around 1840, 1920, and 1980, which are associated with flora projects and the establishment of inventory plots. Most collections were made in the 20th century. The number of collections has increased exponentially, but shows a slowdown in the last two decades. We find that a species' range size is a better predictor of the number of times it has been collected than the species' estimated basin-wide population size. Finding, describing, and documenting the distribution of the remaining species will require coordinated efforts at under-collected sites. PMID:27406027

  11. Simulating spatial distribution and varying patterns of population in Urumqi, China

    Science.gov (United States)

    Chen, Xuegang; Yang, Zhaoping; Zhang, Yuhu; Shi, Qingsan

    2007-11-01

    Taking Urumqi as a case, a simulation of urban population spatial distribution is proposed based on urban land use and population statistical data using GIS, and population spatial distribution patterns are analyzed by the raster population surface. As a result, generating raster population spatial distribution surface is more accurate and natural than the traditional choropleth map of population density in Urumqi. Concerning the population spatial distribution of Urumqi, the population density declines from south to north and the population distribution mainly presents "T-type", the population distribution presents polycentric agglomeration and the population distribution of the districts shows different features. The population density varies significantly with the increase of the distance from CBD. Finally, this paper finds that the development history of districts, terrain and traffic road are main factors influencing Urumqi's population distribution. This paper tries to provide more accurate data of population distribution for the plan and management of urban land, traffic and public facilities in order to enrich the researches of urban population distribution.

  12. Geographic coupling of juvenile and adult habitat shapes spatial population dynamics of a coral reef fish

    NARCIS (Netherlands)

    Huijbers, C.M.; Nagelekerken, I.; Debrot, A.O.; Jongejans, E.

    2013-01-01

    Marine spatial population dynamics are often addressed with a focus on larval dispersal, without taking into account movement behavior of individuals in later life stages. Processes occurring during demersal life stages may also drive spatial population dynamics if habitat quality is perceived diffe

  13. A spatial ecosystem and populations dynamics model (SEAPODYM) Modeling of tuna and tuna-like populations

    Science.gov (United States)

    Lehodey, Patrick; Senina, Inna; Murtugudde, Raghu

    2008-09-01

    An enhanced version of the spatial ecosystem and population dynamics model SEAPODYM is presented to describe spatial dynamics of tuna and tuna-like species in the Pacific Ocean at monthly resolution over 1° grid-boxes. The simulations are driven by a bio-physical environment predicted from a coupled ocean physical-biogeochemical model. This new version of SEAPODYM includes expanded definitions of habitat indices, movements, and natural mortality based on empirical evidences. A thermal habitat of tuna species is derived from an individual heat budget model. The feeding habitat is computed according to the accessibility of tuna predator cohorts to different vertically migrating and non-migrating micronekton (mid-trophic) functional groups. The spawning habitat is based on temperature and the coincidence of spawning fish with presence or absence of predators and food for larvae. The successful larval recruitment is linked to spawning stock biomass. Larvae drift with currents, while immature and adult tuna can move of their own volition, in addition to being advected by currents. A food requirement index is computed to adjust locally the natural mortality of cohorts based on food demand and accessibility to available forage components. Together these mechanisms induce bottom-up and top-down effects, and intra- (i.e. between cohorts) and inter-species interactions. The model is now fully operational for running multi-species, multi-fisheries simulations, and the structure of the model allows a validation from multiple data sources. An application with two tuna species showing different biological characteristics, skipjack ( Katsuwonus pelamis) and bigeye ( Thunnus obesus), is presented to illustrate the capacity of the model to capture many important features of spatial dynamics of these two different tuna species in the Pacific Ocean. The actual validation is presented in a companion paper describing the approach to have a rigorous mathematical parameter optimization

  14. Genetic drift suppresses bacterial conjugation in spatially structured populations

    OpenAIRE

    Freese, Peter D.; Korolev, Kirill S.; Jiménez, José I.; Chen, Irene A.

    2014-01-01

    Conjugation is the primary mechanism of horizontal gene transfer that spreads antibiotic resistance among bacteria. Although conjugation normally occurs in surface-associated growth (e.g., biofilms), it has been traditionally studied in well-mixed liquid cultures lacking spatial structure, which is known to affect many evolutionary and ecological processes. Here we visualize spatial patterns of gene transfer mediated by F plasmid conjugation in a colony of Escherichia coli growing on solid ag...

  15. Study on Simulating Spatial Distribution and Varying Patterns of Urumqi's Population

    Institute of Scientific and Technical Information of China (English)

    Chen Xuegang; Yang Zhaoping; Zhang Xiaolei

    2007-01-01

    In this paper,an approach to simulate the spatial distribution of urban population is proposed using urban land use and population statistical data through the geographical information systems(GIS).Then,the spatial population distribution of Urumqi as a case is simulated by the approach mentioned above and its varying patterns are analyzed by the raster population surface.As a result,producing raster population surface is more accurate and natural than the traditional choropleth map of population density.Concerning the spatial population distribution of Urumqi,the population density declines from south to north and the population distribution mainly presents"T-type",the population distribution presents multi-centre agglomeration and the population distribution of the districts shows different features.The population density varies significantly with the incmase in the distance from central business district(CBD).Finally,it is found in this paper that the development history of districts,terrain and traffic road are main factors that have an influence Urumqi's population distribution.This paper tries to provide more accurate population data for the plan and management of urban land,traffic and public facilities in order to enrich the researches on urban population distribution.

  16. Quantifying spatial genetic structuring in mesophotic populations of the precious coral Corallium rubrum.

    Science.gov (United States)

    Costantini, Federica; Carlesi, Lorenzo; Abbiati, Marco

    2013-01-01

    While shallow water red coral populations have been overharvested in the past, nowadays, commercial harvesting shifted its pressure on mesophotic organisms. An understanding of red coral population structure, particularly larval dispersal patterns and connectivity among harvested populations is paramount to the viability of the species. In order to determine patterns of genetic spatial structuring of deep water Corallium rubrum populations, for the first time, colonies found between 58-118 m depth within the Tyrrhenian Sea were collected and analyzed. Ten microsatellite loci and two regions of mitochondrial DNA (mtMSH and mtC) were used to quantify patterns of genetic diversity within populations and to define population structuring at spatial scales from tens of metres to hundreds of kilometres. Microsatellites showed heterozygote deficiencies in all populations. Significant levels of genetic differentiation were observed at all investigated spatial scales, suggesting that populations are likely to be isolated. This differentiation may by the results of biological interactions, occurring within a small spatial scale and/or abiotic factors acting at a larger scale. Mitochondrial markers revealed significant genetic structuring at spatial scales greater then 100 km showing the occurrence of a barrier to gene flow between northern and southern Tyrrhenian populations. These findings provide support for the establishment of marine protected areas in the deep sea and off-shore reefs, in order to effectively maintain genetic diversity of mesophotic red coral populations. PMID:23646109

  17. Quantifying spatial genetic structuring in mesophotic populations of the precious coral Corallium rubrum.

    Directory of Open Access Journals (Sweden)

    Federica Costantini

    Full Text Available While shallow water red coral populations have been overharvested in the past, nowadays, commercial harvesting shifted its pressure on mesophotic organisms. An understanding of red coral population structure, particularly larval dispersal patterns and connectivity among harvested populations is paramount to the viability of the species. In order to determine patterns of genetic spatial structuring of deep water Corallium rubrum populations, for the first time, colonies found between 58-118 m depth within the Tyrrhenian Sea were collected and analyzed. Ten microsatellite loci and two regions of mitochondrial DNA (mtMSH and mtC were used to quantify patterns of genetic diversity within populations and to define population structuring at spatial scales from tens of metres to hundreds of kilometres. Microsatellites showed heterozygote deficiencies in all populations. Significant levels of genetic differentiation were observed at all investigated spatial scales, suggesting that populations are likely to be isolated. This differentiation may by the results of biological interactions, occurring within a small spatial scale and/or abiotic factors acting at a larger scale. Mitochondrial markers revealed significant genetic structuring at spatial scales greater then 100 km showing the occurrence of a barrier to gene flow between northern and southern Tyrrhenian populations. These findings provide support for the establishment of marine protected areas in the deep sea and off-shore reefs, in order to effectively maintain genetic diversity of mesophotic red coral populations.

  18. Spatially explicit global population scenarios consistent with the Shared Socioeconomic Pathways

    Science.gov (United States)

    Jones, B.; O’Neill, B. C.

    2016-08-01

    The projected size and spatial distribution of the future population are important drivers of global change and key determinants of exposure and vulnerability to hazards. Spatial demographic projections are widely used as inputs to spatial projections of land use, energy use, and emissions, as well as to assessments of the impacts of extreme events, sea level rise, and other climate-related outcomes. To date, however, there are very few global-scale, spatially explicit population projections, and those that do exist are often based on simple scaling or trend extrapolation. Here we present a new set of global, spatially explicit population scenarios that are consistent with the new Shared Socioeconomic Pathways (SSPs) developed to facilitate global change research. We use a parameterized gravity-based downscaling model to produce projections of spatial population change that are quantitatively consistent with national population and urbanization projections for the SSPs and qualitatively consistent with assumptions in the SSP narratives regarding spatial development patterns. We show that the five SSPs lead to substantially different spatial population outcomes at the continental, national, and sub-national scale. In general, grid cell-level outcomes are most influenced by national-level population change, second by urbanization rate, and third by assumptions about the spatial style of development. However, the relative importance of these factors is a function of the magnitude of the projected change in total population and urbanization for each country and across SSPs. We also demonstrate variation in outcomes considering the example of population existing in a low-elevation coastal zone under alternative scenarios.

  19. A Spatial Framework for Understanding Population Structure and Admixture

    Science.gov (United States)

    Bradburd, Gideon S.; Ralph, Peter L.; Coop, Graham M.

    2016-01-01

    Geographic patterns of genetic variation within modern populations, produced by complex histories of migration, can be difficult to infer and visually summarize. A general consequence of geographically limited dispersal is that samples from nearby locations tend to be more closely related than samples from distant locations, and so genetic covariance often recapitulates geographic proximity. We use genome-wide polymorphism data to build “geogenetic maps,” which, when applied to stationary populations, produces a map of the geographic positions of the populations, but with distances distorted to reflect historical rates of gene flow. In the underlying model, allele frequency covariance is a decreasing function of geogenetic distance, and nonlocal gene flow such as admixture can be identified as anomalously strong covariance over long distances. This admixture is explicitly co-estimated and depicted as arrows, from the source of admixture to the recipient, on the geogenetic map. We demonstrate the utility of this method on a circum-Tibetan sampling of the greenish warbler (Phylloscopus trochiloides), in which we find evidence for gene flow between the adjacent, terminal populations of the ring species. We also analyze a global sampling of human populations, for which we largely recover the geography of the sampling, with support for significant histories of admixture in many samples. This new tool for understanding and visualizing patterns of population structure is implemented in a Bayesian framework in the program SpaceMix. PMID:26771578

  20. Explaining spatial heterogeneity in population dynamics and genetics from spatial variation in resources for a large herbivore.

    Directory of Open Access Journals (Sweden)

    Adrienne L Contasti

    Full Text Available Fine-scale spatial variation in genetic relatedness and inbreeding occur across continuous distributions of several populations of vertebrates; however, the basis of observed variation is often left untested. Here we test the hypothesis that prior observations of spatial patterns in genetics for an island population of feral horses (Sable Island, Canada were the result of spatial variation in population dynamics, itself based in spatial heterogeneity in underlying habitat quality. In order to assess how genetic and population structuring related to habitat, we used hierarchical cluster analysis of water sources and an indicator analysis of the availability of important forage species to identify a longitudinal gradient in habitat quality along the length of Sable Island. We quantify a west-east gradient in access to fresh water and availability of two important food species to horses: sandwort, Honckenya peploides, and beach pea, Lathyrus japonicas. Accordingly, the population clusters into three groups that occupy different island segments (west, central, and east that vary markedly in their local dynamics. Density, body condition, and survival and reproduction of adult females were highest in the west, followed by central and east areas. These results mirror a previous analysis of genetics, which showed that inbreeding levels are highest in the west (with outbreeding in the east, and that there are significant differences in fixation indices among groups of horses along the length of Sable Island. Our results suggest that inbreeding depression is not an important limiting factor to the horse population. We conclude that where habitat gradients exist, we can anticipate fine-scale heterogeneity in population dynamics and hence genetics.

  1. Understanding Spatial Statistics for Purposes of Identifying Non-Primary and Saturated Impact Crater Populations

    Science.gov (United States)

    Riggs, J. D.; Robbins, S. J.; Kirchoff, M. R.; Bierhaus, E. B.; Weaver, B. P.

    2015-05-01

    We discuss some traditional unidimensional summarization statistics and some newer spatial point statistical methods for understanding and identifying non-primary and saturated impact crater populations observed on a variety of solar system bodies.

  2. Spatial synchrony of local populations has increased in association with the recent Northern Hemisphere climate trend

    OpenAIRE

    Post, Eric; Forchhammer, Mads C.

    2004-01-01

    According to ecological theory, populations whose dynamics are entrained by environmental correlation face increased extinction risk as environmental conditions become more synchronized spatially. This prediction is highly relevant to the study of ecological consequences of climate change. Recent empirical studies have indicated, for example, that large-scale climate synchronizes trophic interactions and population dynamics over broad spatial scales in freshwater and terrestrial systems. Here...

  3. European Union Enlargement, European Spatial Development Perspective and Regional Policy: Lessons from Population Potentials

    OpenAIRE

    Andrés Faíña; Jesús López-Rodríguez

    2006-01-01

    This paper applies the concept of population potential to study the spatialstructure of the European Economic Space-EU15 and its main changes with theenlargement to Central and Eastern European Countries. The analysis shows a reinforcementof the central areas and a widening and displacement to the East of themiddle areas in the European spatial pattern. Moreover population potential allows usto highlight some policy guidelines for the European Spatial Development Perspectiveand for the future...

  4. Carbon storage in Amazonian podzols

    Science.gov (United States)

    Montes, Celia; Lucas, Yves; Pereira, Osvaldo; Merdy, Patricia; Santin, Roberta; Ishida, Débora; du Gardin, Beryl; Melfi, Adolpho

    2014-05-01

    It has recently been discovered that Amazonian podzols may store much larger quantities of carbon than previously thought, particularly in their deep Bh horizons (over 13.6 Pg for Brazilian Amazonia alone [1]). Similarly high carbon stocks are likely to exist in similar climate/soil areas, mainly in Africa and in Borneo. Such carbon stocks raise the problem of their stability in response to changes in land use or climate. Any significant changes in vegetation cover would significantly alter the soil water dynamics, which is likely to affect organic matter turnover in soils. The direction of the change, however, is not clear and is likely to depend on the specific conditions of carbon storage and properties of the soils. It is reasonable to assume that the drying of the Bh horizons of equatorial podzols, which are generally saturated, will lead to an increase in C mineralization, although the extent of this increase has not yet been determined. These unknowns resulted in research programs, granted by the Brazilian FAPESP and the French Région PACA-ARCUS and ANR, dedicated improving estimates of the Amazonian podzol carbon stocks and to an estimate of its mineralisability. Eight test areas were determined from the analysis of remote sensing data in the larger Amazonian podzol region located in the High Rio Negro catchment and studied in detail. Despite the extreme difficulties in carrying out the field work (difficulties in reaching the study sites and extracting the soils), more than a hundred points were sampled. In all podzols the presence of a thick deep Bh was confirmed, sometimes to depths greater than 12 m. The Bh carbon was quantified, indicating that carbon stocks in these podzols are even higher than estimated recently [1]. References 1- Montes, C.R.; Lucas, Y.; Pereira, O.J.R.; Achard, R.; Grimaldi, M.; Mefli, A.J. Deep plant?derived carbon storage in Amazonian podzols. Biogeosciences, 8, 113?120, 2011.

  5. A spatial analysis of patterns of growth and concentration of population based on homogeneous population censuses: Spain (1877-2001

    Directory of Open Access Journals (Sweden)

    Xavier Franch Auladell

    2013-01-01

    Full Text Available This work constitutes a contribution to the analysis of long term patterns of population concentration applied to the case of Spain. The proposed methodology is based on the homogenisation of both data and administrative units which takes the municipal structure of the 2001 census as its base reference. This work seeks to show how applying spatial analysis techniques to this type of homogeneous data series allows us to make more detailed studies of population patterns within a given territory. The most important conclusions that we reached was that, in Spain, sustained population growth has followed a spatial pattern that has become increasingly consolidated over time. The tendencies observed have produced an uneven distribution of population within the national territory marked by the existence of a series of well-defined, and often very localised, areas that spread beyond the limits of the official administrative boundaries.

  6. Modelling the loss of genetic diversity in vole populations in a spatially and temporally varying environment

    DEFF Research Database (Denmark)

    Topping, Christopher John; Østergaard, Siri; Pertoldi, Cino; Bach, Lars Arve

    2003-01-01

    habitat availability and their influence on vole behaviour. Interaction between spatial and temporal dynamics altered the ratio of effective population size to census size. This indicates an altered reproductive potential, crucial in conservation biology applications. However, when the loss of...... genetically explicit individual-based model (IBM) coupled to a dynamic landscape model was used to obtain measures for the genetic status of simulated vole populations. The rate of loss of expected heterozygosity (He) was calculated for simulated populations using two levels of spatial and temporal...... heterogeneity. Results showed that both spatial and temporal heterogeneity exerted an influence on the rate of loss of genetic diversity, but the precise effect was a balance between the effects of population sub-structuring, the frequency of founder effects and population size. These were in turn related to...

  7. Modeling complex spatial dynamics of two-population interaction in urbanization process

    CERN Document Server

    Chen, Yanguang

    2013-01-01

    This paper is mainly devoted to lay an empirical foundation for further research on complex spatial dynamics of two-population interaction. Based on the US population census data, a rural and urban population interaction model is developed. Subsequently a logistic equation on percentage urban is derived from the urbanization model so that spatial interaction can be connected mathematically with logistic growth. The numerical experiment by using the discretized urban-rural population interaction model of urbanization shows a period-doubling bifurcation and chaotic behavior, which is identical in patterns to those from the simple mathematical models of logistic growth in ecology. This suggests that the complicated dynamics of logistic growth may come from some kind of the nonlinear interaction. The results from this study help to understand urbanization, urban-rural population interaction, chaotic dynamics, and spatial complexity of geographical systems.

  8. SPATIALIZATION MODEL OF POPULATION BASED ON DATASET OF LAND USE AND LAND COVER CHANGE IN CHINA

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The spatialization of population of counties in China is significant. Firstly, we can gain the estimated values of population density adaptive to different kinds of regions. Secondly, we can integrate effectively population data with other data including natural resources, environment, society and economy, build 1km GRIDs of natural resources reserves per person, population density and other economic and environmental data, which are necessary to the national management and macro adjustment and control of natural resources and dynamic monitoring of population. In order to establish population information system serving national decision-making, three steps ought to be followed:1) establishing complete geographical spatial data foundation infrastructure including the establishment of electric map of residence with high resolution using topographical map with large scale and high resolution satellite remote sensing data, the determination of attribute information of housing and office buildings, and creating complete set of attribute database and rapid data updating; 2) establishing complete census systems including improving the transformation efficiency from census data to digital database and strengthening the link of census database and geographical spatial database, meanwhile, the government should attach great importance to the establishment and integration of population migration database; 3) considering there is no GIS software specially serving the analysis and management of population data, a practical approach is to add special modules to present software system, which works as a bridge actualizing the digitization and spatialization of population geography research.

  9. The generation of spatial population distributions from census centroid data

    OpenAIRE

    I Bracken; Martin, D.

    1989-01-01

    Census data are commonly used in geographical analysis and to inform planning purposes, though at the disaggregate level the basis of enumeration poses difficulties. In this paper an approach to surface generation is described that offers the prospect of revealing an underlying population distribution from centroid-based data which is independent of zonal geography. It is suggested that this can serve a wide variety of analytical, cartographic, and policy purposes, including the creation of s...

  10. Spatial and temporal dynamics of the genetic organization of small mammal populations

    International Nuclear Information System (INIS)

    A functional population is a group of organisms and their offspring that contributes to a common gene pool within a certain area and time period. It is also the unit of evolution and should be viewed both in quantitative and qualitative terms. Selection, drift, dispersal, and mutation can alter the composition of populations. Spatial heterogeneity in allele frequencies argues for a conceptual model that has a series of relatively small populations semi-isolated from one another. Because of the relatively high levels of genetic variability characteristic of most mammalian species, significant amounts of gene flow between these spatially subdivided populations must occur when longer time periods are considered. Fluctuations in the genetic structure of populations seem to be important in altering the fitness of the individuals within the populations. The interaction of populations through gene flow is important in changing the levels of intrapopulational genetic variability. Populations can be characterized as existing on a continuum from relatively stable to unstable numbers and by other associated changes in their characteristics. Temporal changes in allele frequency occur in a variety of mammals. Conceptually, a species can be viewed as a series of dynamic populations that vary in numbers and quality in both a spatial and temporal context even over short distances and time periods. Short term changes in the quality of individuals in a population can be important in altering the short term dynamics of a population

  11. Modeling population density across major US cities: a polycentric spatial regression approach

    Science.gov (United States)

    Griffith, Daniel A.; Wong, David W.

    2007-04-01

    A common approach to modeling population density gradients across a city is to adjust the specification of a selected set of mathematical functions to achieve the best fit to an urban place’s empirical density values. In this paper, we employ a spatial regression approach that takes into account the spatial autocorrelation latent in urban population density. We also use a Minkowskian distance metric instead of Euclidean or network distance to better describe spatial separation. We apply our formulation to the 20 largest metropolitan areas in the US according to the 2000 census, using block group level data. The general model furnishes good descriptions for both monocentric and polycentric cities.

  12. Density dependence in marine fish populations revealed at small and large spatial scales.

    Science.gov (United States)

    Johnson, Darren W

    2006-02-01

    Experimental manipulation of population density has frequently been used to demonstrate demographic density dependence. However, such studies are usually small scale and typically provide evidence of spatial (within-generation) density dependence. It is often unclear whether small-scale, experimental tests of spatial density dependence will accurately describe temporal (between-generation) density dependence required for population regulation. Understanding the mechanisms generating density dependence may provide a link between spatial experiments and temporal regulation of populations. In this study, I manipulated the density of recently settled kelp rockfish (Sebastes atrovirens) in both the presence and absence of predators to test for density-dependent mortality and whether predation was the mechanism responsible. I also examined mortality of rockfish cohorts within kelp beds throughout central California to evaluate temporal (between-generation) density dependence in mortality. Experiments suggested that short-term behavioral responses of predators and/or a shortage of prey refuges caused spatial density dependence. Temporal density dependence in mortality was also detected at larger spatial scales for several species of rockfish. It is likely that short-term responses of predators generated both spatial and temporal density dependence in mortality. Spatial experiments that describe the causal mechanisms generating density dependence may therefore be valuable in describing temporal density dependence and population regulation. PMID:16637357

  13. Spatial and spatiotemporal variation in metapopulation structure affects population dynamics in a passively dispersing arthropod.

    Science.gov (United States)

    De Roissart, Annelies; Wang, Shaopeng; Bonte, Dries

    2015-11-01

    The spatial and temporal variation in the availability of suitable habitat within metapopulations determines colonization-extinction events, regulates local population sizes and eventually affects local population and metapopulation stability. Insights into the impact of such a spatiotemporal variation on the local population and metapopulation dynamics are principally derived from classical metapopulation theory and have not been experimentally validated. By manipulating spatial structure in artificial metapopulations of the spider mite Tetranychus urticae, we test to which degree spatial (mainland-island metapopulations) and spatiotemporal variation (classical metapopulations) in habitat availability affects the dynamics of the metapopulations relative to systems where habitat is constantly available in time and space (patchy metapopulations). Our experiment demonstrates that (i) spatial variation in habitat availability decreases variance in metapopulation size and decreases density-dependent dispersal at the metapopulation level, while (ii) spatiotemporal variation in habitat availability increases patch extinction rates, decreases local population and metapopulation sizes and decreases density dependence in population growth rates. We found dispersal to be negatively density dependent and overall low in the spatial variable mainland-island metapopulation. This demographic variation subsequently impacts local and regional population dynamics and determines patterns of metapopulation stability. Both local and metapopulation-level variabilities are minimized in mainland-island metapopulations relative to classical and patchy ones. PMID:25988264

  14. An Analysis on the Spatial Distribution of Population Aging Pressure in China

    Institute of Scientific and Technical Information of China (English)

    YangWangzhou; Dong Suocheng; Wu Youde; Luo Renbo

    2012-01-01

    Based on comprehensive analysis of the impact of population aging to social and economic development, a comprehensive evaluation system including 18 indexes was constructed for evaluating regional pressure of population aging on social and economic development. Using statistics data of 31 regions in Chi- na from 2004 to 2008, the pressure of population aging on social and economic development, was comprehensively evaluated by using the factor analysis method. The spatial distribution of popu- lation aging in China was also analyzed. This study is to provide scientific basis for government to make strategies of coping with population aging according to regional pressure of population ag- ing on social and economic development in China.

  15. Restricted dispersal reduces the strength of spatial density dependence in a tropical bird population

    OpenAIRE

    Burgess, Malcolm D; Nicoll, Malcolm A. C.; Jones, Carl G; Norris, Ken

    2008-01-01

    Spatial processes could play an important role in density-dependent population regulation because the disproportionate use of poor quality habitats as population size increases is widespread in animal populations—the so-called buffer effect. While the buffer effect patterns and their demographic consequences have been described in a number of wild populations, much less is known about how dispersal affects distribution patterns and ultimately density dependence. Here, we investigated the role...

  16. Population dynamics and spatial distribution of Griffon Vultures (Gyps fulvus) Portugal

    OpenAIRE

    Beest, van, I.; Bremer, van den, L.; Boer; Heitkonig, I.M.A.; Monteiro, A.E.

    2008-01-01

    The global decrease of vulture populations has been attributed to several factors, such as food availability, poisoning, human disturbance, or habitat suitability. We studied the effect of factors that vary both spatially and temporally on the nest site distribution of the Griffon Vulture Gyps fulvus in northeast Portugal, and influence the population dynamics of these cliff-dwelling birds. Several demographic parameters were studied in the field, and the age structure of the population was d...

  17. Spatial concentration of population in Serbia 1981-2011 measured with the Hoover index

    OpenAIRE

    Šantić Danica

    2014-01-01

    Population distribution reflects the integrity of natural, social, economic and historical factors of the geospace, relevant both for fundamental and applied research. Complex spatial structure of the contemporary distribution of population in the world, and Serbia as well, during history was determined by human migrations of complex scope and determinants. The aim of this paper was to describe and analyze the geographical redistribution of the population b...

  18. Comparison of three plot selection methods for estimating change in temporally variable, spatially clustered populations; TOPICAL

    International Nuclear Information System (INIS)

    Monitoring population numbers is important for assessing trends and meeting various legislative mandates. However, sampling across time introduces a temporal aspect to survey design in addition to the spatial one. For instance, a sample that is initially representative may lose this attribute if there is a shift in numbers and/or spatial distribution in the underlying population that is not reflected in later sampled plots. Plot selection methods that account for this temporal variability will produce the best trend estimates. Consequently, I used simulation to compare bias and relative precision of estimates of population change among stratified and unstratified sampling designs based on permanent, temporary, and partial replacement plots under varying levels of spatial clustering, density, and temporal shifting of populations. Permanent plots produced more precise estimates of change than temporary plots across all factors. Further, permanent plots performed better than partial replacement plots except for high density (5 and 10 individuals per plot) and 25% - 50% shifts in the population. Stratified designs always produced less precise estimates of population change for all three plot selection methods, and often produced biased change estimates and greatly inflated variance estimates under sampling with partial replacement. Hence, stratification that remains fixed across time should be avoided when monitoring populations that are likely to exhibit large changes in numbers and/or spatial distribution during the study period. Key words: bias; change estimation; monitoring; permanent plots; relative precision; sampling with partial replacement; temporary plots

  19. Extended Shared Socioeconomic Pathways for Coastal Impact Assessment: Spatial Coastal Population Scenarios

    Science.gov (United States)

    Merkens, Jan-Ludolf; Reimann, Lena; Hinkel, Jochen; Vafeidis, Athanasios T.

    2016-04-01

    This work extends the Shared Socioeconomic Pathways (SSPs) by developing spatial projections of global coastal population distribution for the five basic SSPs. Based on a series of coastal migration drivers, which were identified from existing literature, we develop coastal narratives for the five basic SSPs (SSP1-5). These narratives account for differences in coastal versus inland population development in urban and rural areas. To spatially distribute population we use the International Institute for Applied Systems Analysis (IIASA) national population and urbanisation projections and employ country-specific growth rates which differ for coastal and inland as well as for urban and rural regions. These rates are derived from spatial analysis of historical population data. We then adjust these rates for each SSP based on the coastal narratives. The resulting global population grids depict the projected distribution of coastal population for each SSP, until the end of the 21st century, at a spatial resolution of 30 arc seconds. These grids exhibit a three- to four-fold increase in coastal population compared to the basic SSPs. Across all SSPs, except for SSP3, coastal population peaks by the middle of the 21st century and declines afterwards. In SSP3 the coastal population grows continuously until 2100. Compared to the base year 2000 the coastal population increases considerably in all SSPs. The extended SSPs are intended to be utilised in Impact, Adaptation and Vulnerability (IAV) assessments as they allow for improved analysis of exposure to sea-level rise and coastal flooding under different physical and socioeconomic scenarios.

  20. Spatial Estimation of Populations at Risk from Radiological Dispersion Device Terrorism Incidents

    International Nuclear Information System (INIS)

    Delineation of the location and size of the population potentially at risk of exposure to ionizing radiation is one of the key analytical challenges in estimating accurately the severity of the potential health effects associated with a radiological terrorism incident. Regardless of spatial scale, the geographical units for which population data commonly are collected rarely coincide with the geographical scale necessary for effective incident management and medical response. This paper identifies major government and commercial open sources of U.S. population data and presents a GIS-based approach for allocating publicly available population data, including age distributions, to geographical units appropriate for planning and implementing incident management and medical response strategies. In summary: The gravity model offers a straight-forward, empirical tool for estimating population flows, especially when geographical areas are relatively well-defined in terms of accessibility and spatial separation. This is particularly important for several reasons. First, the spatial scale for the area impacted by a RDD terrorism event is unlikely to match fully the spatial scale of available population data. That is, the plume spread typically will not uniformly overlay the impacted area. Second, the number of people within the impacted area varies as a function whether an attack occurs during the day or night. For example, the population of a central business district or industrial area typically is larger during the day while predominately residential areas have larger night time populations. As a result, interpolation techniques that link population data to geographical units and allocate those data based on time-frame at a spatial scale that is relevant to enhancing preparedness and response. The gravity model's main advantage is that it efficiently allocates readily available, open source population data to geographical units appropriate for planning and implementing

  1. Spatial and temporal dynamics of fucoid populations (Ascophyllum nodosum and Fucus serratus: a comparison between central and range edge populations.

    Directory of Open Access Journals (Sweden)

    Rita M Araújo

    Full Text Available Persistence of populations at range edges relies on local population dynamics and fitness, in the case of geographically isolated populations of species with low dispersal potential. Focusing on spatial variations in demography helps to predict the long-term capability for persistence of populations across the geographical range of species' distribution. The demography of two ecological and phylogenetically close macroalgal species with different life history characteristics was investigated by using stochastic, stage-based matrix models. Populations of Ascophyllum nodosum and Fucus serratus were sampled for up to 4 years at central locations in France and at their southern range limits in Portugal. The stochastic population growth rate (λ(s of A. nodosum was lower and more variable in central than in southern sites whilst for F. serratus this trend was reversed with λ(s much lower and more variable in southern than in central populations. Individuals were larger in central than in southern populations for both species, which was reflected in the lower transition probabilities of individuals to larger size classes and higher probability of shrinkage in the southern populations. In both central and southern populations elasticity analysis (proportional sensitivity of population growth rate showed that fertility elements had a small contribution to λ(s that was more sensitive to changes in matrix transitions corresponding to survival. The highest elasticities were found for loop transitions in A. nodosum and for growth to larger size classes in F. serratus. Sensitivity analysis showed high selective pressure on individual growth for both species at both locations. The results of this study highlight the deterministic role of species-specific life-history traits in population demography across the geographical range of species. Additionally, this study demonstrates that individuals' life-transitions differ in vulnerability to environmental

  2. A high resolution spatial population database of Somalia for disease risk mapping

    Directory of Open Access Journals (Sweden)

    Linard Catherine

    2010-09-01

    Full Text Available Abstract Background Millions of Somali have been deprived of basic health services due to the unstable political situation of their country. Attempts are being made to reconstruct the health sector, in particular to estimate the extent of infectious disease burden. However, any approach that requires the use of modelled disease rates requires reasonable information on population distribution. In a low-income country such as Somalia, population data are lacking, are of poor quality, or become outdated rapidly. Modelling methods are therefore needed for the production of contemporary and spatially detailed population data. Results Here land cover information derived from satellite imagery and existing settlement point datasets were used for the spatial reallocation of populations within census units. We used simple and semi-automated methods that can be implemented with free image processing software to produce an easily updatable gridded population dataset at 100 × 100 meters spatial resolution. The 2010 population dataset was matched to administrative population totals projected by the UN. Comparison tests between the new dataset and existing population datasets revealed important differences in population size distributions, and in population at risk of malaria estimates. These differences are particularly important in more densely populated areas and strongly depend on the settlement data used in the modelling approach. Conclusions The results show that it is possible to produce detailed, contemporary and easily updatable settlement and population distribution datasets of Somalia using existing data. The 2010 population dataset produced is freely available as a product of the AfriPop Project and can be downloaded from: http://www.afripop.org.

  3. Detection of Amazonian Black Earth Sites using Hyperspectral Satellite Imagery

    Science.gov (United States)

    Braswell, B. H.; Palace, M.; Bush, M. B.; Neves, E.; Mcmichael, C.; Czarnecki, C.; Moraes, B.; Raczka, M.

    2012-12-01

    The pre-Columbian indigenous population estimates of the Amazon Basin lowlands are highly uncertain and the subject of considerable controversy. One of the archaeological sources used in reconstruction of Amazonian societies are Amazonian black earths (ABE) or terra preta soils. The immense size of Amazonia, remoteness of many areas, forest vegetation, and lack of archaeological field surveys, make remote sensing beneficial to archaeological studies in this region. Remote sensing allows for comparison and analysis of vegetation across vast areas. Previous research has shown that hyperspectral image data can detect vegetation canopy chemistry differences, associated with soil nutrients and chemistry anomalies at ABE locations. We conducted a preliminary analysis that indicates nine portions of the spectrum where three ABE sites are completely separable from the three non-ABE sites. A discriminant function analysis using stepwise variable selection indicated that five bands were adequate in distinguishing between ABE and non-ABE sites. These five bands ranged between the 2000-2400 nm, indicating that canopy moisture is useful in remotely sensing terra preta. The wealth of site locations we are compiling from numerous sources provides a unique opportunity to develop algorithms for the classification of ABE and non-ABE sites. Our current data holdings include over 1600 Hyperion images and a database of ABE/ non-ABE field observations at approximately 2900 sites. The distribution and number of ABE sites provides information useful for both archaeological research and has consequences for the interpretation of Amazonian forest ecology. Knowledge of the disturbance history of the Amazonian forest provides a context and framework for the placement of all environmental research in the region. This presentation reports results of statistical modeling using extracted spectra from about 400 sites that are within Hyperion scenes.

  4. Low plant density enhances gene dispersal in the Amazonian understory herb Heliconia acuminata.

    Science.gov (United States)

    Côrtes, Marina C; Uriarte, María; Lemes, Maristerra R; Gribel, Rogério; Kress, W John; Smouse, Peter E; Bruna, Emilio M

    2013-11-01

    In theory, conservation genetics predicts that forest fragmentation will reduce gene dispersal, but in practice, genetic and ecological processes are also dependent on other population characteristics. We used Bayesian genetic analyses to characterize parentage and propagule dispersal in Heliconia acuminata L. C. Richard (Heliconiaceae), a common Amazonian understory plant that is pollinated and dispersed by birds. We studied these processes in two continuous forest sites and three 1-ha fragments in Brazil's Biological Dynamics of Forest Fragments Project. These sites showed variation in the density of H. acuminata. Ten microsatellite markers were used to genotype flowering adults and seedling recruits and to quantify realized pollen and seed dispersal distances, immigration of propagules from outside populations, and reproductive dominance among parents. We tested whether gene dispersal is more dependent on fragmentation or density of reproductive plants. Low plant densities were associated with elevated immigration rates and greater propagule dispersal distances. Reproductive dominance among inside-plot parents was higher for low-density than for high-density populations. Elevated local flower and fruit availability is probably leading to spatially more proximal bird foraging and propagule dispersal in areas with high density of reproductive plants. Nevertheless, genetic diversity, inbreeding coefficients and fine-scale spatial genetic structure were similar across populations, despite differences in gene dispersal. This result may indicate that the opposing processes of longer dispersal events in low-density populations vs. higher diversity of contributing parents in high-density populations balance the resulting genetic outcomes and prevent genetic erosion in small populations and fragments. PMID:24730040

  5. Mapping populations at risk: improving spatial demographic data for infectious disease modeling and metric derivation

    Directory of Open Access Journals (Sweden)

    Tatem Andrew J

    2012-05-01

    Full Text Available Abstract The use of Global Positioning Systems (GPS and Geographical Information Systems (GIS in disease surveys and reporting is becoming increasingly routine, enabling a better understanding of spatial epidemiology and the improvement of surveillance and control strategies. In turn, the greater availability of spatially referenced epidemiological data is driving the rapid expansion of disease mapping and spatial modeling methods, which are becoming increasingly detailed and sophisticated, with rigorous handling of uncertainties. This expansion has, however, not been matched by advancements in the development of spatial datasets of human population distribution that accompany disease maps or spatial models. Where risks are heterogeneous across population groups or space or dependent on transmission between individuals, spatial data on human population distributions and demographic structures are required to estimate infectious disease risks, burdens, and dynamics. The disease impact in terms of morbidity, mortality, and speed of spread varies substantially with demographic profiles, so that identifying the most exposed or affected populations becomes a key aspect of planning and targeting interventions. Subnational breakdowns of population counts by age and sex are routinely collected during national censuses and maintained in finer detail within microcensus data. Moreover, demographic and health surveys continue to collect representative and contemporary samples from clusters of communities in low-income countries where census data may be less detailed and not collected regularly. Together, these freely available datasets form a rich resource for quantifying and understanding the spatial variations in the sizes and distributions of those most at risk of disease in low income regions, yet at present, they remain unconnected data scattered across national statistical offices and websites. In this paper we discuss the deficiencies of existing

  6. Mapping populations at risk: improving spatial demographic data for infectious disease modeling and metric derivation.

    Science.gov (United States)

    Tatem, Andrew J; Adamo, Susana; Bharti, Nita; Burgert, Clara R; Castro, Marcia; Dorelien, Audrey; Fink, Gunter; Linard, Catherine; John, Mendelsohn; Montana, Livia; Montgomery, Mark R; Nelson, Andrew; Noor, Abdisalan M; Pindolia, Deepa; Yetman, Greg; Balk, Deborah

    2012-01-01

    The use of Global Positioning Systems (GPS) and Geographical Information Systems (GIS) in disease surveys and reporting is becoming increasingly routine, enabling a better understanding of spatial epidemiology and the improvement of surveillance and control strategies. In turn, the greater availability of spatially referenced epidemiological data is driving the rapid expansion of disease mapping and spatial modeling methods, which are becoming increasingly detailed and sophisticated, with rigorous handling of uncertainties. This expansion has, however, not been matched by advancements in the development of spatial datasets of human population distribution that accompany disease maps or spatial models.Where risks are heterogeneous across population groups or space or dependent on transmission between individuals, spatial data on human population distributions and demographic structures are required to estimate infectious disease risks, burdens, and dynamics. The disease impact in terms of morbidity, mortality, and speed of spread varies substantially with demographic profiles, so that identifying the most exposed or affected populations becomes a key aspect of planning and targeting interventions. Subnational breakdowns of population counts by age and sex are routinely collected during national censuses and maintained in finer detail within microcensus data. Moreover, demographic and health surveys continue to collect representative and contemporary samples from clusters of communities in low-income countries where census data may be less detailed and not collected regularly. Together, these freely available datasets form a rich resource for quantifying and understanding the spatial variations in the sizes and distributions of those most at risk of disease in low income regions, yet at present, they remain unconnected data scattered across national statistical offices and websites.In this paper we discuss the deficiencies of existing spatial population datasets and

  7. The spatial specificities of SC and ST population in Kolkata city: approaches, techniques and analysis

    Directory of Open Access Journals (Sweden)

    Mishra, Swasti Vardhan

    2012-06-01

    Full Text Available The paper aims at achieving two objectives, firstly, to acquaint the researchers in the field of spatial demography with the techniques of residential segregation; pattern of population distribution based on the concept of spatial statistics and secondly, the practical evaluation of the techniques through real life data. The study queries about any residential segregation and pattern of location of the scheduled caste (SC and the scheduled tribe (ST population in Kolkata city by concentrating on the measures of Entropy Index (EI, Atkinson’s Index, Absolute Centralization Index (ACE and the Global and Local Spatial Autocorrelation (SA measures of Moran’s I and LISA. The outcome of the study clarifies the fact that caste and race based segregation is being diluted in the wake of Indian urbanization and the spatial clustering tendency of the Concerned Social Group (CSG is as mild.

  8. demoniche – an R-package for simulating spatially-explicit population dynamics

    DEFF Research Database (Denmark)

    Nenzén, Hedvig K.; Swab, Rebecca Marie; Keith, David A.;

    2012-01-01

    demoniche is a freely available R-package which simulates stochastic population dynamics in multiple populations of a species. A demographic model projects population sizes utilizing several transition matrices that can represent impacts on species growth. The demoniche model offers options...... for setting demographic stochasticity, carrying capacity, and dispersal. The demographic projection in each population is linked to spatially-explicit niche values, which affect the species growth. With the demoniche package it is possible to compare the influence of scenarios of environmental changes...

  9. Population coding of visual space: comparison of spatial representations in the dorsal and ventral pathways

    Directory of Open Access Journals (Sweden)

    Anne B Sereno

    2011-02-01

    Full Text Available Although the representation of space is as fundamental to visual processing as the representation of shape, it has received relatively little attention from neurophysiological investigations. In this study we characterize representations of space within visual cortex, and examine how they differ in a first direct comparison between dorsal and ventral subdivisions of the visual pathways. Neural activities were recorded in anterior inferotemporal cortex (AIT and lateral intraparietal cortex (LIP of awake behaving monkeys, structures associated with the ventral and dorsal visual pathways respectively, as a stimulus was presented at different locations within the visual field. In spatially selective cells, we find greater modulation of cell responses in LIP with changes in stimulus position. Further, using a novel population-based statistical approach (namely, multidimensional scaling, we recover the spatial map implicit within activities of neural populations, allowing us to quantitatively compare the geometry of neural space with physical space. We show that a population of spatially selective LIP neurons, despite having large receptive fields, is able to almost perfectly reconstruct stimulus locations within a low-dimensional representation. In contrast, a population of AIT neurons, despite each cell being spatially selective, provide less accurate low-dimensional reconstructions of stimulus locations. They produce instead only a topologically (categorically correct rendition of space, which nevertheless might be critical for object and scene recognition. Furthermore, we found that the spatial representation recovered from population activity shows greater translation invariance in LIP than in AIT. We suggest that LIP spatial representations may be dimensionally isomorphic with 3D physical space, while in AIT spatial representations may reflect a more categorical representation of space (e.g., next to or above.

  10. Fire patterns in the Amazonian biome

    Science.gov (United States)

    Aragao, Luiz E. O. C.; Shimabukuro, Yosio E.; Lima, Andre; Anderson, Liana O.; Barbier, Nicolas; Saatchi, Sassan

    2010-05-01

    This paper aims to provide an overview of our recent findings on the interplay between climate and land use dynamics in defining fire patterns in Amazonia. Understanding these relationships is currently a fundamental concern for assessing the vulnerability of Amazonia to climate change and its potential for mitigating current increases in atmospheric greenhouse gases. Reducing carbon emissions from tropical deforestation and forest degradation (REDD), for instance, could contribute to a cumulative emission reduction of 13-50 billion tons of carbon (GtC) by 2100. In Amazonia, though, forest fires can release similar quantities of carbon to the atmosphere (~0.2 GtC yr-1) as deforestation alone. Therefore, to achieve carbon savings through REDD mechanism there is an urgent need of understanding and subsequently restraining related Amazonian fire drivers. In this study, we analyze satellite-derived monthly and annual time-series of fires, rainfall and deforestation in Amazonia to: (1) quantify the seasonal patterns and relationships between these variables; (2) quantify fire and rainfall anomalies to evaluate the impact of recent drought on fire patterns; (3) quantify recent trends in fire and deforestation to understand how land use affects fire patterns in Amazonia. Our results demonstrate a marked seasonality of fires. The majority of fires occurs along the Arc of Deforestation, the expanding agricultural frontier in southern and eastern Amazonia, indicating humans are the major ignition sources determining fire seasonality, spatial distribution and long-term patterns. There is a marked seasonality of fires, which is highly correlated (pslash-and-burn of Amazonian vegetation for implementation of pastures and agricultural fields. The cumulative number of hot pixels is exponentially related to the monthly rainfall, which ultimately defines where and when fire can potentially strike. During the 2005 Amazonian drought, the number of hot pixels increased 33% in relation

  11. SPATIALIZATION MODEL OF POPULATION BASED ON DATASET OF LAND USE AND LAND COVER CHANGE IN CHINA

    Institute of Scientific and Technical Information of China (English)

    ZHUANGDa-fang; LIUMing-liang; 等

    2002-01-01

    The spatialization of population of counties in China is significant.Fistly,we can gain the estimated val-ues of population density adaptive to different kinds of regions.Secondly,we can integrate effectively population data with other data including natural resources,environment,society and economy,build 1km GRIDs of natural resources re-serves per person,population density and other economic and environmental data,which are necessary to the national manage-ment and macro adjustment and control of natural resources and dynamic monitoring of population.In order to establish population information system serving national decision-making,three steps ought to be followed:1)establishing complete geographical spatial data foundation infrastructure including the establishment of electric map of residence with high resolu-tion using topographical map with large scale and high resolution satellite remote sensing data,the determination of at-tribute information of housing and office buildings,and creating complete set of attribute database and rapid data update-ing;2) establishing complete census systems including improving the transformation efficiency from census data to digital database and strengthening the link of census database and geographical spatial database,meanwhile,the government should attach great importance to the establishment and integration o population migration database;3)considering there is no GIS software specially seving the analysis and management of population data,a practical approach is to add spe-cial modules to present software system,which works as a bring actualizing the digitization and spatialization of popula-tion geography research.

  12. The Impact of Population, Contact, and Spatial Heterogeneity on Epidemic Model Predictions.

    Science.gov (United States)

    Zagmutt, Francisco J; Schoenbaum, Mark A; Hill, Ashley E

    2016-05-01

    Our objective was to evaluate the effect that complexity in the form of different levels of spatial, population, and contact heterogeneity has in the predictions of a mechanistic epidemic model. A model that simulates the spatiotemporal spread of infectious diseases between animal populations was developed. Sixteen scenarios of foot-and-mouth disease infection in cattle were analyzed, involving combinations of the following factors: multiple production-types (PT) with heterogeneous contact and population structure versus single PT, random versus actual spatial distribution of population units, high versus low infectivity, and no vaccination versus preemptive vaccination. The epidemic size and duration was larger for scenarios with multiple PT versus single PT. Ignoring the actual unit locations did not affect the epidemic size in scenarios with multiple PT/high infectivity, but resulted in smaller epidemic sizes in scenarios using multiple PT/low infectivity. In conclusion, when modeling fast-spreading epidemics, knowing the actual locations of population units may not be as relevant as collecting information on population and contact heterogeneity. In contrast, both population and spatial heterogeneity might be important to model slower spreading epidemic diseases. Our findings can be used to inform data collection and modeling efforts to inform health policy and planning. PMID:26477887

  13. A Wave-Spectrum Analysis of Urban Population Density: Entropy, Fractal, and Spatial Localization

    OpenAIRE

    Yanguang Chen

    2008-01-01

    The method of spectral analysis is employed to research the spatial dynamics of urban population distribution. First of all, the negative exponential model is derived in a new way by using an entropy-maximizing idea. Then an approximate scaling relation between wave number and spectral density is derived by Fourier transform of the negative exponential model. The theoretical results suggest the locality of urban population activities. So the principle of entropy maximization can be utilized t...

  14. Individual movement behavior, matrix heterogeneity, and the dynamics of spatially structured populations

    OpenAIRE

    Revilla, Eloy; Wiegand, Thorsten

    2008-01-01

    The dynamics of spatially structured populations is characterized by within- and between-patch processes. The available theory describes the latter with simple distance-dependent functions that depend on landscape properties such as interpatch distance or patch size. Despite its potential role, we lack a good mechanistic understanding of how the movement of individuals between patches affects the dynamics of these populations. We used the theoretical framework provided by movement ecology to ...

  15. Spatial distribution of stellar populations in the Magellanic Clouds: Implementation to Gaia

    OpenAIRE

    Belcheva, M. K.; Livanou, E.; Kontizas, M.; Nikolov, G. B.; Kontizas, E.

    2010-01-01

    The main goal of our project is to investigate the spatial distribution of different stellar populations in the Magellanic Clouds. The results from modelling the Magellanic Clouds can be useful, among others, for simulations during the Gaia mission preparation. Isodensity contour maps have been used in order to trace the morphology of the different stellar populations and estimate the size of these structures. Moreover, star density maps are constructed through star counts and projected radia...

  16. Atlantic bluefin tuna: a novel multistock spatial model for assessing population biomass.

    Directory of Open Access Journals (Sweden)

    Nathan G Taylor

    Full Text Available Atlantic bluefin tuna (Thunnus thynnus is considered to be overfished, but the status of its populations has been debated, partly because of uncertainties regarding the effects of mixing on fishing grounds. A better understanding of spatial structure and mixing may help fisheries managers to successfully rebuild populations to sustainable levels while maximizing catches. We formulate a new seasonally and spatially explicit fisheries model that is fitted to conventional and electronic tag data, historic catch-at-age reconstructions, and otolith microchemistry stock-composition data to improve the capacity to assess past, current, and future population sizes of Atlantic bluefin tuna. We apply the model to estimate spatial and temporal mixing of the eastern (Mediterranean and western (Gulf of Mexico populations, and to reconstruct abundances from 1950 to 2008. We show that western and eastern populations have been reduced to 17% and 33%, respectively, of 1950 spawning stock biomass levels. Overfishing to below the biomass that produces maximum sustainable yield occurred in the 1960s and the late 1990s for western and eastern populations, respectively. The model predicts that mixing depends on season, ontogeny, and location, and is highest in the western Atlantic. Assuming that future catches are zero, western and eastern populations are predicted to recover to levels at maximum sustainable yield by 2025 and 2015, respectively. However, the western population will not recover with catches of 1750 and 12,900 tonnes (the "rebuilding quotas" in the western and eastern Atlantic, respectively, with or without closures in the Gulf of Mexico. If future catches are double the rebuilding quotas, then rebuilding of both populations will be compromised. If fishing were to continue in the eastern Atlantic at the unregulated levels of 2007, both stocks would continue to decline. Since populations mix on North Atlantic foraging grounds, successful rebuilding

  17. Spatially heterogeneous populations with mixed negative and positive local density dependence.

    Science.gov (United States)

    Knipl, Diána; Röst, Gergely

    2016-06-01

    Identifying the steady states of a population is a key issue in theoretical ecology, that includes the study of spatially heterogeneous populations. There are several examples of real ecosystems in patchy environments where the habitats are heterogeneous in their local density dependence. We investigate a multi-patch model of a single species with spatial dispersal, where the growth of the local population is logistic in some localities (negative density dependence) while other patches exhibit a strong Allee effect (positive density dependence). When the local dynamics is logistic in each patch and the habitats are interconnected by dispersal then the total population has only the extinction steady state and a componentwise positive equilibrium, corresponding to persistence in each patch. We show that animal populations in patchy environments can have a large number of steady states if local density dependence varies over the locations. It is demonstrated that, depending on the network topology of migration routes between the patches, the interaction of spatial dispersal and local density dependence can create a variety of coexisting stable positive equilibria. We give a detailed description of the multiple ways dispersal can rescue local populations from extinction. PMID:26801607

  18. Historical effects on beta diversity and community assembly in Amazonian trees

    Science.gov (United States)

    Dexter, Kyle G.; Terborgh, John W.; Cunningham, Clifford W.

    2012-01-01

    We present a unique perspective on the role of historical processes in community assembly by synthesizing analyses of species turnover among communities with environmental data and independent, population genetic-derived estimates of among-community dispersal. We sampled floodplain and terra firme communities of the diverse tree genus Inga (Fabaceae) across a 250-km transect in Amazonian Peru and found patterns of distance-decay in compositional similarity in both habitat types. However, conventional analyses of distance-decay masked a zone of increased species turnover present in the middle of the transect. We estimated past seed dispersal among the same communities by examining geographic plastid DNA variation for eight widespread Inga species and uncovered a population genetic break in the majority of species that is geographically coincident with the zone of increased species turnover. Analyses of these and 12 additional Inga species shared between two communities located on opposite sides of the zone showed that the populations experienced divergence 42,000–612,000 y ago. Our results suggest that the observed distance decay is the result not of environmental gradients or dispersal limitation coupled with ecological drift—as conventionally interpreted under neutral ecological theory—but rather of secondary contact between historically separated communities. Thus, even at this small spatial scale, historical processes seem to significantly impact species’ distributions and community assembly. Other documented zones of increased species turnover found in the western Amazon basin or elsewhere may be related to similar historical processes. PMID:22547831

  19. Late Amazonian Glaciations in Utopia Planitia, Mars

    Science.gov (United States)

    Osinski, G. R.; Capitan, R. D.; Kerrigan, M.; Barry, N.; Blain, S.

    2012-03-01

    We present evidence from western Utopia Planitia, including lineated valley fill and lobate debris aprons, for widespread glaciations over a large expanse of the northern plains and dichotomy boundary during Late Amazonian times.

  20. Temporally increasing spatial synchrony of North American temperature and bird populations

    Science.gov (United States)

    Koenig, Walter D.; Liebhold, Andrew M.

    2016-06-01

    The ecological impacts of modern global climate change are detectable in a wide variety of phenomena, ranging from shifts in species ranges to changes in community composition and human disease dynamics. So far, however, little attention has been given to temporal changes in spatial synchrony--the coincident change in abundance or value across the landscape--despite the importance of environmental synchrony as a driver of population trends and the central role of environmental variability in population rescue and extinction. Here we demonstrate that across North America, spatial synchrony of a significant proportion of 49 widespread North American wintering bird species has increased over the past 50 years--the period encompassing particularly intense anthropogenic effects in climate--paralleling significant increases in spatial synchrony of mean maximum air temperature. These results suggest the potential for increased spatial synchrony in environmental factors to be affecting a wide range of ecological phenomena. These effects are likely to vary, but for North American wildlife species, increased spatial synchrony driven by environmental factors may be the basis for a previously unrecognized threat to their long-term persistence in the form of more synchronized population dynamics reducing the potential for demographic rescue among interacting subpopulations.

  1. Amazonian Dark Earth and plant species from the Amazon region contribute to shape rhizosphere bacterial communities

    NARCIS (Netherlands)

    Barbosa Lima, A.; Souza Cannavan, F.S.; Navarrete, A.A.; Kuramae, E.E.; Teixeira, W.G.; Tsai, S.M.

    2015-01-01

    Amazonian Dark Earths (ADE) or Terra Preta de Índio formed in the past by pre-Columbian populations are highly sustained fertile soils supported by microbial communities that differ from those extant in adjacent soils. These soils are found in the Amazon region and are considered as a model soil whe

  2. Evaluating the Spatial Distributions of Ethnic Populations: A Quantitative Exercise for Undergraduates.

    Science.gov (United States)

    Rivizzigno, Victoria L.

    This exercise teaches undergraduate geography students to use the Lorenz Curve and the Index of Dissimilarity to assess the spatial distributions of the White, Black, and American Indian populations of the United States in 1980. Specific procedures for implementing the exercise are provided; solutions to the exercise are also included. Students…

  3. Population dynamics and spatial distribution of Griffon Vultures (Gyps fulvus) Portugal

    NARCIS (Netherlands)

    Beest, van F.M.; Bremer, van den L.; Boer, de W.F.; Heitkonig, I.M.A.; Monteiro, A.E.

    2008-01-01

    The global decrease of vulture populations has been attributed to several factors, such as food availability, poisoning, human disturbance, or habitat suitability. We studied the effect of factors that vary both spatially and temporally on the nest site distribution of the Griffon Vulture Gyps fulvu

  4. DEFINING RECOVERY GOALS AND STRATEGIES FOR ENDANGERED SPECIES USING SPATIALLY-EXPLICIT POPULATION MODELS

    Science.gov (United States)

    We used a spatially explicit population model of wolves (Canis lupus) to propose a framework for defining rangewide recovery priorities and finer-scale strategies for regional reintroductions. The model predicts that Yellowstone and central Idaho, where wolves have recently been ...

  5. A spatial age-structured model for describing sea lamprey (Petromyzon marinus) population dynamics

    Science.gov (United States)

    Robinson, Jason M.; Wilberg, Michael J.; Adams, Jean V.; Jones, Michael L.

    2013-01-01

    The control of invasive sea lampreys (Petromyzon marinus) presents large scale management challenges in the Laurentian Great Lakes. No modeling approach has been developed that describes spatial dynamics of lamprey populations. We developed and validated a spatial and age-structured model and applied it to a sea lamprey population in a large river in the Great Lakes basin. We considered 75 discrete spatial areas, included a stock-recruitment function, spatial recruitment patterns, natural mortality, chemical treatment mortality, and larval metamorphosis. Recruitment was variable, and an upstream shift in recruitment location was observed over time. From 1993–2011 recruitment, larval abundance, and the abundance of metamorphosing individuals decreased by 80, 84, and 86%, respectively. The model successfully identified areas of high larval abundance and showed that areas of low larval density contribute significantly to the population. Estimated treatment mortality was less than expected but had a large population-level impact. The results and general approach of this work have applications for sea lamprey control throughout the Great Lakes and for the restoration and conservation of native lamprey species globally.

  6. Antimicrobial activity of amazonian medicinal plants

    OpenAIRE

    Oliveira, Amanda A; Segovia, Jorge FO; Sousa, Vespasiano YK; Mata, Elida CG; Gonçalves, Magda CA; Bezerra, Roberto M; Junior, Paulo OM; Kanzaki, Luís IB

    2013-01-01

    Objectives The aqueous extracts of currently utilized Amazonian medicinal plants were assayed in vitro searching for antimicrobial activity against human and animal pathogenic microorganisms. Methods Medium resuspended lyophilized aqueous extracts of different organs of Amazonian medicinal plants were assayed by in vitro screening for antimicrobial activity. ATCC and standardized microorganisms obtained from Oswaldo Cruz Foundation/Brazil were individually and homogeneously grown in agar plat...

  7. ANALYSIS ON THE DYNAMICS OF SPATIAL DISTRIBUTION PATTERN OF MIXED SPIDER POPULATION IN RICE FIELD

    Institute of Scientific and Technical Information of China (English)

    ZhiWang; Zhe-mingYuan; Da-xiangSong; Ming-shengZhu

    2004-01-01

    The results make it clear that there are total 11 families, 29 genera and 43 species of spiders in the rice field of Dong Fang Hong Farm. Among them, there are 8 families, 19 genera and 28 species in the early rice field, and 10 families, 27 genera and 36 species in the late rice field. The spatial distribution pattern of mixed spider populations in rice fields was different during different development stages of rice plant. During the prophase, metaphase and anaphase of early rice plant development, the spatial distribution pattern of mixed spider populations was aggregative, random and aggregative respectively. During the prophase, metaphase and anaphase of late rice plant development, the spatial distribution pattern was uniform, aggregative and uniform respectively.

  8. Counting Cats: Spatially Explicit Population Estimates of Cheetah (Acinonyx jubatus) Using Unstructured Sampling Data

    Science.gov (United States)

    Broekhuis, Femke; Gopalaswamy, Arjun M.

    2016-01-01

    Many ecological theories and species conservation programmes rely on accurate estimates of population density. Accurate density estimation, especially for species facing rapid declines, requires the application of rigorous field and analytical methods. However, obtaining accurate density estimates of carnivores can be challenging as carnivores naturally exist at relatively low densities and are often elusive and wide-ranging. In this study, we employ an unstructured spatial sampling field design along with a Bayesian sex-specific spatially explicit capture-recapture (SECR) analysis, to provide the first rigorous population density estimates of cheetahs (Acinonyx jubatus) in the Maasai Mara, Kenya. We estimate adult cheetah density to be between 1.28 ± 0.315 and 1.34 ± 0.337 individuals/100km2 across four candidate models specified in our analysis. Our spatially explicit approach revealed ‘hotspots’ of cheetah density, highlighting that cheetah are distributed heterogeneously across the landscape. The SECR models incorporated a movement range parameter which indicated that male cheetah moved four times as much as females, possibly because female movement was restricted by their reproductive status and/or the spatial distribution of prey. We show that SECR can be used for spatially unstructured data to successfully characterise the spatial distribution of a low density species and also estimate population density when sample size is small. Our sampling and modelling framework will help determine spatial and temporal variation in cheetah densities, providing a foundation for their conservation and management. Based on our results we encourage other researchers to adopt a similar approach in estimating densities of individually recognisable species. PMID:27135614

  9. Counting Cats: Spatially Explicit Population Estimates of Cheetah (Acinonyx jubatus) Using Unstructured Sampling Data.

    Science.gov (United States)

    Broekhuis, Femke; Gopalaswamy, Arjun M

    2016-01-01

    Many ecological theories and species conservation programmes rely on accurate estimates of population density. Accurate density estimation, especially for species facing rapid declines, requires the application of rigorous field and analytical methods. However, obtaining accurate density estimates of carnivores can be challenging as carnivores naturally exist at relatively low densities and are often elusive and wide-ranging. In this study, we employ an unstructured spatial sampling field design along with a Bayesian sex-specific spatially explicit capture-recapture (SECR) analysis, to provide the first rigorous population density estimates of cheetahs (Acinonyx jubatus) in the Maasai Mara, Kenya. We estimate adult cheetah density to be between 1.28 ± 0.315 and 1.34 ± 0.337 individuals/100km2 across four candidate models specified in our analysis. Our spatially explicit approach revealed 'hotspots' of cheetah density, highlighting that cheetah are distributed heterogeneously across the landscape. The SECR models incorporated a movement range parameter which indicated that male cheetah moved four times as much as females, possibly because female movement was restricted by their reproductive status and/or the spatial distribution of prey. We show that SECR can be used for spatially unstructured data to successfully characterise the spatial distribution of a low density species and also estimate population density when sample size is small. Our sampling and modelling framework will help determine spatial and temporal variation in cheetah densities, providing a foundation for their conservation and management. Based on our results we encourage other researchers to adopt a similar approach in estimating densities of individually recognisable species. PMID:27135614

  10. Population structure, spatial distribution and life-history traits of blacktip reef sharks Carcharhinus melanopterus.

    Science.gov (United States)

    Mourier, J; Mills, S C; Planes, S

    2013-03-01

    During a survey of the population of blacktip reef shark Carcharhinus melanopterus in Moorea (French Polynesia) between 2007 and 2011, population structural characteristics were estimated from 268 individuals. Total length (LT ) ranged from 48 to 139 cm and 48 to 157 cm for males and females, respectively, demonstrating that the average LT of females was larger than that of males. The C. melanopterus population at Moorea showed an apparent spatial sexual segregation with females preferentially frequenting lagoons and males the fore-reefs. Mean growth rate was c. 6 cm year(-1) . Males reached sexual maturity at 111 cm LT . This study reports on the population characteristics of this widespread carcharhinid shark species and makes comparisons with other locations, confirming high geographic variability in the population structure of the species. PMID:23464555

  11. Development of population geography from antropogeography to spatial-analitical approach

    Directory of Open Access Journals (Sweden)

    Spasovski Milena

    2013-01-01

    .N. Anučin, J. Beaujeu-Gariner. G. Trewarta argued that the population is the point of reference from which all other elements are observed and from which all derive significance and meaning. This view was adopted and shared by authors dealing with population items, explicitly or implicitly. Second stage lasted from 1960s till 1970s and the most significant authors dealing with population problems were W. Zelinsky, W. Bunge; H.Bobek, W. Hartke, K.Ruppert, F.Schaffer; D.I. Valentej, K.Korčak. This phase was characterized by the application of quantitative methods and efforts for understanding the spatial structure of the population. Many scientists see this development phase as a particularly prosperous period, because it carried more intensive relations of geography and demography through the introduction of statistical, mathematical and demographic methods and techniques in studies of population geography. Third phase lasted from 1970s to 1980s, and was characterized by close relations between population geography and formal demography. Development and application of GIS and computer data, have made population studies more complex and applicable in practice, through population policy and population projections. The most significant authors in this period were L. Kosinski, A. Jagelski, Hägerstrand. And at last, fourth stage started in 1980s and in many countries lastes untill present days. In population geography appeared new tendencies associated with the critique of positivism, the establishment of humanistic approaches and modifications of general geographic concepts. In this period, spatial analysis and quantitative scientific methods were reaffirmed, and because of that some population studies were redefined in spatial demography, a time dimension advocated in historical demography. In this context, we emphasize the work of D. Plane and P. Rogerson. Population geography is viewed differently from one country to another. Its definition differs from too narrow to

  12. Spatially explicit models for inference about density in unmarked or partially marked populations

    Science.gov (United States)

    Chandler, Richard B.; Royle, J. Andrew

    2013-01-01

    Recently developed spatial capture–recapture (SCR) models represent a major advance over traditional capture–recapture (CR) models because they yield explicit estimates of animal density instead of population size within an unknown area. Furthermore, unlike nonspatial CR methods, SCR models account for heterogeneity in capture probability arising from the juxtaposition of animal activity centers and sample locations. Although the utility of SCR methods is gaining recognition, the requirement that all individuals can be uniquely identified excludes their use in many contexts. In this paper, we develop models for situations in which individual recognition is not possible, thereby allowing SCR concepts to be applied in studies of unmarked or partially marked populations. The data required for our model are spatially referenced counts made on one or more sample occasions at a collection of closely spaced sample units such that individuals can be encountered at multiple locations. Our approach includes a spatial point process for the animal activity centers and uses the spatial correlation in counts as information about the number and location of the activity centers. Camera-traps, hair snares, track plates, sound recordings, and even point counts can yield spatially correlated count data, and thus our model is widely applicable. A simulation study demonstrated that while the posterior mean exhibits frequentist bias on the order of 5–10% in small samples, the posterior mode is an accurate point estimator as long as adequate spatial correlation is present. Marking a subset of the population substantially increases posterior precision and is recommended whenever possible. We applied our model to avian point count data collected on an unmarked population of the northern parula (Parula americana) and obtained a density estimate (posterior mode) of 0.38 (95% CI: 0.19–1.64) birds/ha. Our paper challenges sampling and analytical conventions in ecology by demonstrating

  13. Spatial structure of the spider crab, Maja brachydactyla population: Evidence of metapopulation structure

    Science.gov (United States)

    Corgos, Antonio; Bernárdez, Cristina; Sampedro, Paz; Verísimo, Patricia; Freire, Juan

    2011-08-01

    Distribution and spatial population structure of the spider crab, Maja brachydactyla, in the Ría de A Coruña (NW Spain) and adjacent coastal area was analysed. Sampling was done with experimental traps placed in three shallow bottom sampling stations and the central channel of the Ría, from December 1997 to November 1999. Crabs were tagged to study their movements on a small scale (1-10 km). Mean catches were substantially higher in the inner Ría station (Bastiagueiro) and were significantly higher in sandy substrates. Crabs inhabiting rocky bottoms moved to sandy bottoms from summer to autumn. Two local populations comprising mainly juveniles were identified —one located in Bastiagueiro and the other in Canide. There was no evidence of any major exchange between the juveniles of the two populations nor were juveniles observed to move towards deeper zones. Most of these juveniles reached maturity in summer and migrated to deeper waters. Adult catches and the recaptured specimens from both the experimental sampling and the commercial fishery indicate that the local Bastiagueiro population contributes a much greater number of individuals to the adult crab population in deep waters than does the Canide population. The spatial structure of the population of M. brachydactyla in the Ría de A Coruña may be defined as a part of a postlarval metapopulation made up of two shallow water local juvenile crab populations that migrate to deeper waters after attaining maturity. A pool of adults (and indirectly of larvae) from several local populations is formed in deeper waters. There is strong evidence that local populations are linked by larval dispersal.

  14. Some regularity of dynamics in spatial and territorial distribution of insect population density

    International Nuclear Information System (INIS)

    Full text: Complexity and many-sidedness of inter-population and inter-ecosystematic interrelations in biological systems in any territory of natural utilisation must be coordinated with pest control methods. There are no exceptions to the integrating use of sterile insects with other control technologies. Therefore, the determination of self-regulatory characteristics in respect of inter-ecosystematic changes in spatial and territorial distribution of insect populations in large territories acquires special significance. The aim of this work is to review the dynamic processes of spatial and territorial distribution of host-parasitoid complexes in various ecosystems in Lithuania. Investigation into mosaicism of natural communities for any given territory, their development dynamics, and the regularities of formation of host-parasitoid complexities is a very urgent problem not only in all biological respect but also in practical activities. The regularities of functioning of ecosystems are very important for the management of insect pest populations and for the optimisation of the structure of agricultural landscapes. Long-term ecological research has been conducted in different ecosystems of Lithuania, such as the coniferous, deciduous and mixed forests, bushes and riversides, forest parks and orchards. Populations of various ermine moths, pine beauty and their parasitoids have been observed on pine, bird cherry, apple, hawthorn, spindle, sloe and service trees. The results of our study conducted for the last three decades in Lithuania indicated that as a result of the combination of the dynamic differences in the population densities of some species of phytophagous and entomophagous insects, the mosaicism of spatial distribution of their populations, and the character displacement in various ecosystems, the redistribution over the territory may be observed regularly and everywhere. Significant redistribution and movement of the definite level of insect population

  15. Temporal and spatial variations in wildlife population fluctuations in Greenland; The effect of climate, environment and man

    OpenAIRE

    Moshøj, Charlotte Margaret; Forchhammer, Mads C.; Forbes, Valery E.

    2009-01-01

    Temporal and spatial variations in wildlife population fluctuations in Greenland; The effect of climate, environment and man Moshøj, C.M, M.C.Forchhammer and V.E. Forbes Temporal and spatial variations in wildlife population fluctuations in Greenland; The effect of climate, environment and man: The underlying factors of species fluctuating population dynamics has been the dominant focus of attention in population ecology throughout much of this century. In arctic regions where a severe climat...

  16. Estimating the spatial distribution of wintering little brown bat populations in the eastern United States

    Science.gov (United States)

    Russell, Robin E.; Tinsley, Karl; Erickson, Richard A.; Thogmartin, Wayne E.; Jennifer A. Szymanski

    2014-01-01

    Depicting the spatial distribution of wildlife species is an important first step in developing management and conservation programs for particular species. Accurate representation of a species distribution is important for predicting the effects of climate change, land-use change, management activities, disease, and other landscape-level processes on wildlife populations. We developed models to estimate the spatial distribution of little brown bat (Myotis lucifugus) wintering populations in the United States east of the 100th meridian, based on known hibernacula locations. From this data, we developed several scenarios of wintering population counts per county that incorporated uncertainty in the spatial distribution of the hibernacula as well as uncertainty in the size of the current little brown bat population. We assessed the variability in our results resulting from effects of uncertainty. Despite considerable uncertainty in the known locations of overwintering little brown bats in the eastern United States, we believe that models accurately depicting the effects of the uncertainty are useful for making management decisions as these models are a coherent organization of the best available information.

  17. Perceptual load affects spatial tuning of neuronal populations in human early visual cortex.

    OpenAIRE

    Haas, B.; Schwarzkopf, D. S.; Anderson, E. J.; Rees, G

    2014-01-01

    Summary Withdrawal of attention from a visual scene as a result of perceptual load modulates overall levels of activity in human visual cortex [1], but its effects on cortical spatial tuning properties are unknown. Here we show attentional load at fixation affects the spatial tuning of population receptive fields (pRFs) in early visual cortex (V1–3) using functional magnetic resonance imaging (fMRI). We found that, compared to low perceptual load, high perceptual load yielded a ‘blurrier’ rep...

  18. Spatial distribution pattern, scale and gap characteristics of Pinus armandii population in Qinling Mountains, China

    Institute of Scientific and Technical Information of China (English)

    LAN Guoyu; CHEN Wei; LEI Ruide

    2007-01-01

    Based on the data collected from 27 plots of the Pinus armandii community in Qinling Mountains,we studied the spatial distribution pattern,scale,and gap characteristics of the P.armandii population.The results showed that the population had a clumped distribution before age 50.At the age range from 15 to 25,though the population tended to be distributed randomly,the distribution was still clumped.The population distribution at the age range from 40 to 50 was at the transitional stage from clumped to random.After age 50,the population started to be senesced,the distribution pattern turning from clumped to random.The distribution pattern scale of P.armandii always changes with the development stage of the population,being 100 m2 in general.The gap size of P armandii population was similar to its distribution pattem scale,and the gaps of 80-130 m2 occupied 59% of the total.Because of the better light and nutrient condition in the gap,P.armandii seedlings grew well,which helped the population keep its stability through "mobile mosaic circling".

  19. Population responses to environmental change in a tropical ant: the interaction of spatial and temporal dynamics.

    Directory of Open Access Journals (Sweden)

    Doug Jackson

    Full Text Available Spatial structure can have a profound, but often underappreciated, effect on the temporal dynamics of ecosystems. Here we report on a counterintuitive increase in the population of a tree-nesting ant, Azteca sericeasur, in response to a drastic reduction in the number of potential nesting sites. This surprising result is comprehensible when viewed in the context of the self-organized spatial dynamics of the ants and their effect on the ants' dispersal-limited natural enemies. Approximately 30% of the trees in the study site, a coffee agroecosystem in southern Mexico, were pruned or felled over a two-year period, and yet the abundance of the ant nests more than doubled over the seven-year study. Throughout the transition, the spatial distribution of the ants maintained a power-law distribution - a signal of spatial self organization - but the local clustering of the nests was reduced post-pruning. A cellular automata model incorporating the changed spatial structure of the ants and the resulting partial escape from antagonists reproduced the observed increase in abundance, highlighting how self-organized spatial dynamics can profoundly influence the responses of ecosystems to perturbations.

  20. Spatial genetic structure and mitochondrial DNA phylogeography of Argentinean populations of the grasshopper Dichroplus elongatus.

    Directory of Open Access Journals (Sweden)

    Natalia Rosetti

    Full Text Available Many grasshopper species are considered of agronomical importance because they cause damage to pastures and crops. Comprehension of pest population dynamics requires a clear understanding of the genetic diversity and spatial structure of populations. In this study we report on patterns of genetic variation in the South American grasshopper Dichroplus elongatus which is an agricultural pest of crops and forage grasses of great economic significance in Argentina. We use Direct Amplification of Minisatellite Regions (DAMD and partial sequences of the cytochrome oxydase 1 (COI mitochondrial gene to investigate intraspecific structure, demographic history and gene flow patterns in twenty Argentinean populations of this species belonging to different geographic and biogeographic regions. DAMD data suggest that, although genetic drift and migration occur within and between populations, measurable relatedness among neighbouring populations declines with distance and dispersal over distances greater than 200 km is not typical, whereas effective gene flow may occur for populations separated by less than 100 km. Landscape analysis was useful to detect genetic discontinuities associated with environmental heterogeneity reflecting the changing agroecosystem. The COI results indicate the existence of strong genetic differentiation between two groups of populations located at both margins of the Paraná River which became separated during climate oscillations of the Middle Pleistocene, suggesting a significant restriction in effective dispersion mediated by females and large scale geographic differentiation. The number of migrants between populations estimated through mitochondrial and DAMD markers suggest that gene flow is low prompting a non-homogeneous spatial structure and justifying the variation through space. Moreover, the genetic analysis of both markers allows us to conclude that males appear to disperse more than females, reducing the chance of the

  1. Stellar population gradients and spatially resolved kinematics in luminous post-starburst galaxies

    CERN Document Server

    Pracy, M B; Sadler, E; Couch, W J; Kuntschner, H; Bekki, K; Owers, M S; Zwaan, M; Turner, J; Bergmann, M

    2013-01-01

    We have used deep integral field spectroscopy obtained with the GMOS instrument on Gemini-North to determine the spatial distribution of the post-starburst stellar population in four luminous E+A galaxies at z<0.04. We find all four galaxies have centrally-concentrated gradients in the young stellar population contained within the central ~1 kpc. This is in agreement with the Balmer line gradients found in local low luminosity E+A galaxies. The results from higher redshift (z~0.1) samples of luminous E+A galaxies have been varied, but in general have found the post-starburst signature to be extended or a galaxy-wide phenomenon or have otherwise failed to detect gradients in the stellar populations. The ubiquity of the detection of a centrally concentrated young stellar population in local samples, and the presence of significant radial gradients in the stellar populations when the E+A galaxy core is well resolved raises the possibility that spatial resolution issues may be important in interpreting the hig...

  2. Population Density and Spatial Distribution Pattern of Hypera postica (Coleoptera: Curculionidae) in Ardabil, Iran

    OpenAIRE

    Mona MORADI-VAJARGAH; Golizadeh, Ali; Hooshang RAFIEE-DASTJERDI; Zalucki, Myron P; Hassanpour, Mehdi; Naseri, Bahram

    2011-01-01

    The alfalfa weevil, Hypera postica (Gyllenhal), feeds almost exclusively on alfalfa, Medicago sativa L. in most region of the world where forage crop is grown. It has been investigated the population density and spatial distribution of alfalfa weevil on alfalfa in Ardabil during 2010. Using a 0.25 m2 quadrate sample unit a reliable sample size was 65, with maximum relative variation of 15%. The relative variation (RV) of the primary sampling data was 13.6. The highest population density of th...

  3. [Spatial population distribution and development: notes on urban settlements in Latin America].

    Science.gov (United States)

    Jordan, R

    1982-04-01

    The relationship between population distribution and development trends is analyzed, with attention to the planning of spatial redistribution policies. Some shortcomings in the investigation of the causes and consequences of urbanization are discussed. The second part of the article "refers to some spatial demographic and socio-economic expressions of the urbanization process in Latin America, the population concentration trends and their relationships with changes in agrarian structure and industrialization, social stratification patterns and forms of urban space organization.... The paper concludes with some critical notes on the theses related to 'optimum' size of urban centres and to 'balanced development' of urban systems, on which some policy proposals have been based." (summary in ENG) PMID:12264230

  4. Consumo alimentar e ecologia de populações ribeirinhas em dois ecossistemas amazônicos: um estudo comparativo Food intake and ecology of riverine populations in two Amazonian ecosystems: a comparative analysis

    Directory of Open Access Journals (Sweden)

    Rui Sérgio Sereni Murrieta

    2008-08-01

    Full Text Available OBJETIVO: Este artigo analisa e compara os dados de consumo alimentar de duas populações ribeirinhas da Amazônia vivendo em ecossistemas contrastantes de floresta tropical: a várzea estacional e a floresta de terra firme. MÉTODOS: Foi estudado o consumo alimentar de 11 unidades domésticas na várzea (Ilha de Ituqui, Município de Santarém e 17 na terra firme (Floresta Nacional de Caxiuanã, Municípios de Melgaço e Portel. O método utilizado foi o recordatório de 24 horas. As análises estatísticas foram executadas com o auxílio do programa Statistical Package for Social Sciences 12.0. RESULTADOS: Em ambos os ecossistemas, os resultados confirmam a centralidade do pescado e da mandioca na dieta local. Porém, a contribuição de outros itens alimentares secundários, tais como o açaí (em Caxiuanã e o leite in natura (em Ituqui, também foi significante. Além disso, o açúcar revelou ser uma fonte de energia confiável para enfrentar as flutuações sazonais dos recursos naturais. Parece haver ainda uma maior contribuição energética dos peixes para a dieta de Ituqui, provavelmente em função da maior produtividade dos rios e lagos da várzea em relação à terra firme. Por fim, Ituqui revelou uma maior dependência de itens alimentares comprados, enquanto Caxiuanã mostrou estar ainda bastante vinculada à agricultura e às redes locais de troca. CONCLUSÃO: Além dos resultados confirmarem a importância do pescado e da mandioca, também mostraram que produtos industrializados, como o açúcar, têm um papel importante nas dietas, podendo apontar para tendências no consumo alimentar relacionadas com a atual transição nutricional e com a erosão, em diferentes níveis, dos sistemas de subsistência locais.OBJECTIVE: This article analyses and compares data on household food intake of two Amazonian riverine populations settled in different rain forest ecosystems: terra firme (land not subject to annual flooding forest and

  5. Noise and Correlations in a Spatial Population Model with Cyclic Competition

    CERN Document Server

    Reichenbach, Tobias; Frey, Erwin

    2007-01-01

    Noise and spatial degrees of freedom characterize most ecosystems. Some aspects of their influence on the coevolution of populations with cyclic interspecies competition have been demonstrated in recent experiments [e.g. B. Kerr et al., Nature {\\bf 418}, 171 (2002)]. To reach a better theoretical understanding of these phenomena, we consider a paradigmatic spatial model where three species exhibit cyclic dominance. Using an individual-based description, as well as stochastic partial differential and deterministic reaction-diffusion equations, we account for stochastic fluctuations and spatial diffusion at different levels, and show how fascinating patterns of entangled spirals emerge. We rationalize our analysis by computing the spatio-temporal correlation functions and provide analytical expressions for the front velocity and the wavelength of the propagating spiral waves.

  6. Non-additive and non-stationary properties in the spatial distribution of a large marine fish population

    OpenAIRE

    Ciannelli, Lorenzo; Bartolino, Valerio; Chan, Kung-Sik

    2012-01-01

    Density-independent and density-dependent variables both affect the spatial distributions of species. However, their effects are often separately addressed using different analytical techniques. We apply a spatially explicit regression framework that incorporates localized, interactive and threshold effects of both density-independent (water temperature) and density-dependent (population abundance) variables, to study the spatial distribution of a well-monitored flatfish population in the eas...

  7. Counting Cats: Spatially Explicit Population Estimates of Cheetah (Acinonyx jubatus) Using Unstructured Sampling Data

    OpenAIRE

    Broekhuis, Femke; Gopalaswamy, Arjun M.

    2016-01-01

    Many ecological theories and species conservation programmes rely on accurate estimates of population density. Accurate density estimation, especially for species facing rapid declines, requires the application of rigorous field and analytical methods. However, obtaining accurate density estimates of carnivores can be challenging as carnivores naturally exist at relatively low densities and are often elusive and wide-ranging. In this study, we employ an unstructured spatial sampling field des...

  8. Counting cats: spatially explicit population estimates of cheetah (acinonyx jubatus) using unstructured sampling data

    OpenAIRE

    Broekhuis, F.; Gopalaswamy, AM

    2016-01-01

    Many ecological theories and species conservation programmes rely on accurate estimates of population density. Accurate density estimation, especially for species facing rapid declines, requires the application of rigorous field and analytical methods. However, obtaining accurate density estimates of carnivores can be challenging as carnivores naturally exist at relatively low densities and are often elusive and wide-ranging. In this study, we employ an unstructured spatial sampling field des...

  9. Spatial Clustering of HIV Prevalence in Atlanta, Georgia and Population Characteristics Associated with Case Concentrations

    OpenAIRE

    Hixson, Brooke A.; Omer, Saad B; Del Rio, Carlos; Frew, Paula M.

    2011-01-01

    We assessed prevalent HIV cases in Atlanta to examine case distribution trends and population characteristics at the census tract level that may be associated with clustering effects. We calculated cluster characteristics (area and internal HIV prevalence) via Kuldorff's spatial scan method. Subsequent logistic regression analyses were performed to analyze sociodemographics associated with inclusion in a cluster. Organizations offering voluntary HIV testing and counseling services were identi...

  10. Some vector borne diseases with structured host populations: extinction and spatial spread

    OpenAIRE

    Gourley, Stephen A.; Liu, Rongsong; Wu, Jianhong

    2007-01-01

    We derive from a structured population model a system of delay differential equations describing the interaction of five subpopulations, namely susceptible and infected adult and juvenile reservoirs and infected adult vectors, for a vector borne disease with particular reference to West Nile virus, and we also incorporate spatial movements by considering the analogue reaction diffusion systems with nonlocal delayed terms. Specific conditions for the disease eradication and sharp conditions fo...

  11. Connecting multiple spatial scales to decode the population activity of grid cells

    OpenAIRE

    Stemmler, Martin; Mathis, Alexander; Andreas V. M Herz

    2015-01-01

    Mammalian grid cells fire when an animal crosses the points of an imaginary hexagonal grid tessellating the environment. We show how animals can navigate by reading out a simple population vector of grid cell activity across multiple spatial scales, even though neural activity is intrinsically stochastic. This theory of dead reckoning explains why grid cells are organized into discrete modules within which all cells have the same lattice scale and orientation. The lattice scale changes from m...

  12. Spatially structured populations with a low level of cryptic diversity in European marine Gastrotricha

    OpenAIRE

    Kieneke, Alexander; Martinez Arbizu, Pedro; Fontaneto, Diego

    2012-01-01

    Species of the marine meiofauna such as Gastrotricha are known to lack dispersal stages and are thus assumed to have low dispersal ability and low levels of gene flow between populations. Yet, most species are widely distributed, and this creates a paradox. To shed light on this apparent paradox, we test (i) whether such wide distribution may be due to misidentification and lumping of cryptic species with restricted distributions and (ii) whether spatial structures exist for the phylogeograph...

  13. Spatial analysis of corresponding fingerprint features from match and close non-match populations.

    Science.gov (United States)

    Abraham, Joshua; Champod, Christophe; Lennard, Chris; Roux, Claude

    2013-07-10

    The development of statistical models for forensic fingerprint identification purposes has been the subject of increasing research attention in recent years. This can be partly seen as a response to a number of commentators who claim that the scientific basis for fingerprint identification has not been adequately demonstrated. In addition, key forensic identification bodies such as ENFSI [1] and IAI [2] have recently endorsed and acknowledged the potential benefits of using statistical models as an important tool in support of the fingerprint identification process within the ACE-V framework. In this paper, we introduce a new Likelihood Ratio (LR) model based on Support Vector Machines (SVMs) trained with features discovered via morphometric and spatial analyses of corresponding minutiae configurations for both match and close non-match populations often found in AFIS candidate lists. Computed LR values are derived from a probabilistic framework based on SVMs that discover the intrinsic spatial differences of match and close non-match populations. Lastly, experimentation performed on a set of over 120,000 publicly available fingerprint images (mostly sourced from the National Institute of Standards and Technology (NIST) datasets) and a distortion set of approximately 40,000 images, is presented, illustrating that the proposed LR model is reliably guiding towards the right proposition in the identification assessment of match and close non-match populations. Results further indicate that the proposed model is a promising tool for fingerprint practitioners to use for analysing the spatial consistency of corresponding minutiae configurations. PMID:23153799

  14. Population dynamics and spatial distribution of Abaris basistriata Chaudoir, 1873 (Coleoptera: Carabidae

    Directory of Open Access Journals (Sweden)

    Ivan Carlos Fernandes Martins

    2016-02-01

    Full Text Available ABSTRACT Abaris basistriata, a beetle species dominant in agroecosystems and natural habitats, may benefit from the establishment of nearby refuge areas or crop field centers. To confirm this hypothesis, we analyzed the spatial distribution of the species and verified the population dynamics of this predator in a soybean/corn rotation crop and a central refuge area. The 1-ha experimental area was divided in half by a range of herbaceous plants (2 m in width and 80 m in length. Beetle samples were collected using pitfall traps every fortnight during the in-season and every month during the off-season (a total of 27 sampling occurrences. Population fluctuation was analyzed by correlating the total number of specimens with plant phenology. We used multiple regression analysis with variable (stepwise selection to examine the influence of meteorological factors on species occurrence. To determine the spatial distribution, data were analyzed using dispersion indices and probabilistic models based on the Coleoptera frequency distribution. Distribution visualization was assessed using a linear interpolation map. A total of 143 A. basistriata specimens were collected, with 83 from the soybean/corn area and 60 from the refuge area. Periods of large population size occurred during a season with high rainfall and high maximum and minimum temperatures. On the basis of the spatial distribution analysis of A. basistriata, it is likely that the beetles occur in an aggregate form, preferably in the refuge area.

  15. Fire-free land use in pre-1492 Amazonian savannas.

    Science.gov (United States)

    Iriarte, José; Power, Mitchell J; Rostain, Stéphen; Mayle, Francis E; Jones, Huw; Watling, Jennifer; Whitney, Bronwen S; McKey, Doyle B

    2012-04-24

    The nature and scale of pre-Columbian land use and the consequences of the 1492 "Columbian Encounter" (CE) on Amazonia are among the more debated topics in New World archaeology and paleoecology. However, pre-Columbian human impact in Amazonian savannas remains poorly understood. Most paleoecological studies have been conducted in neotropical forest contexts. Of studies done in Amazonian savannas, none has the temporal resolution needed to detect changes induced by either climate or humans before and after A.D. 1492, and only a few closely integrate paleoecological and archaeological data. We report a high-resolution 2,150-y paleoecological record from a French Guianan coastal savanna that forces reconsideration of how pre-Columbian savanna peoples practiced raised-field agriculture and how the CE impacted these societies and environments. Our combined pollen, phytolith, and charcoal analyses reveal unexpectedly low levels of biomass burning associated with pre-A.D. 1492 savanna raised-field agriculture and a sharp increase in fires following the arrival of Europeans. We show that pre-Columbian raised-field farmers limited burning to improve agricultural production, contrasting with extensive use of fire in pre-Columbian tropical forest and Central American savanna environments, as well as in present-day savannas. The charcoal record indicates that extensive fires in the seasonally flooded savannas of French Guiana are a post-Columbian phenomenon, postdating the collapse of indigenous populations. The discovery that pre-Columbian farmers practiced fire-free savanna management calls into question the widely held assumption that pre-Columbian Amazonian farmers pervasively used fire to manage and alter ecosystems and offers fresh perspectives on an emerging alternative approach to savanna land use and conservation that can help reduce carbon emissions. PMID:22493248

  16. Population genetics at three spatial scales of a rare sponge living in fragmented habitats

    Directory of Open Access Journals (Sweden)

    Uriz Maria J

    2010-01-01

    Full Text Available Abstract Background Rare species have seldom been studied in marine habitats, mainly because it is difficult to formally assess the status of rare species, especially in patchy benthic organisms, for which samplings are often assumed to be incomplete and, thus, inappropriate for establishing the real abundance of the species. However, many marine benthic invertebrates can be considered rare, due to the fragmentation and rarity of suitable habitats. Consequently, studies on the genetic connectivity of rare species in fragmented habitats are basic for assessing their risk of extinction, especially in the context of increased habitat fragmentation by human activities. Sponges are suitable models for studying the intra- and inter-population genetic variation of rare invertebrates, as they produce lecitotrophic larvae and are often found in fragmented habitats. Results We investigated the genetic structure of a Mediterranean sponge, Scopalina lophyropoda (Schmidt, using the allelic size variation of seven specific microsatellite loci. The species can be classified as "rare" because of its strict habitat requirements, the low number of individuals per population, and the relatively small size of its distribution range. It also presents a strong patchy distribution, philopatric larval dispersal, and both sexual and asexual reproduction. Classical genetic-variance-based methods (AMOVA and differentiation statistics revealed that the genetic diversity of S. lophyropoda was structured at the three spatial scales studied: within populations, between populations of a geographic region, and between isolated geographic regions, although some stochastic gene flow might occur among populations within a region. The genetic structure followed an isolation-by-distance pattern according to the Mantel test. However, despite philopatric larval dispersal and fission events in the species, no single population showed inbreeding, and the contribution of clonality to the

  17. Ecological complexity in a coffee agroecosystem: spatial heterogeneity, population persistence and biological control.

    Directory of Open Access Journals (Sweden)

    Heidi Liere

    Full Text Available BACKGROUND: Spatial heterogeneity is essential for the persistence of many inherently unstable systems such as predator-prey and parasitoid-host interactions. Since biological interactions themselves can create heterogeneity in space, the heterogeneity necessary for the persistence of an unstable system could be the result of local interactions involving elements of the unstable system itself. METHODOLOGY/PRINCIPAL FINDINGS: Here we report on a predatory ladybird beetle whose natural history suggests that the beetle requires the patchy distribution of the mutualism between its prey, the green coffee scale, and the arboreal ant, Azteca instabilis. Based on known ecological interactions and the natural history of the system, we constructed a spatially-explicit model and showed that the clustered spatial pattern of ant nests facilitates the persistence of the beetle populations. Furthermore, we show that the dynamics of the beetle consuming the scale insects can cause the clustered distribution of the mutualistic ants in the first place. CONCLUSIONS/SIGNIFICANCE: From a theoretical point of view, our model represents a novel situation in which a predator indirectly causes a spatial pattern of an organism other than its prey, and in doing so facilitates its own persistence. From a practical point of view, it is noteworthy that one of the elements in the system is a persistent pest of coffee, an important world commodity. This pest, we argue, is kept within limits of control through a complex web of ecological interactions that involves the emergent spatial pattern.

  18. Amazonian dark earths and Caboclo subsistence on the middle Madeira River, Brazil

    OpenAIRE

    Fraser, James Angus

    2010-01-01

    This thesis examines the relationship between Amazonian Dark Earths (ADE) and Caboclo subsistence on the Middle Madeira River, Brazil. ADE are fertile anthropogenic (man-made) soils formed through practices of burning and waste disposal by pre-Columbian Amerindian populations. “Caboclo” is a social category that refers to the people of diverse origins that form the majority of the contemporary rural population of Brazilian Amazonia. Bitter manioc fields (roças) and homegardens (sítios) are th...

  19. Spatial Interaction Modeling to Identify Potentially Exposed Populations during RDD or IND Terrorism Incidents

    International Nuclear Information System (INIS)

    Homeland Security Presidential Directive no.5 (HSPD-5) Management of Domestic Incidents and Department of Homeland Security (DHS) Planning Guidance for Protection and Recovery Following Radiological Dispersal Device (RDD) and Improvised Nuclear Device (IND) Incidents underscore the need to delineate radiological emergency guidance applicable to remedial action and recovery following an RDD or IND incident. Rapid delineation of the population potentially exposed to ionizing radiation from fallout during terrorist incidents involving RDDs or low-yield nuclear devices (≤ 20 KT) is necessary for effective medical response and incident management as part of the recovery process. This paper illustrates the application of spatial interaction models to allocate population data for a representative U.S. urban area (≅1.3M people; 1,612.27 km2 area) at a geographical scale relevant for accurately estimating risk given dose concentrations. Estimated total dose equivalents (TEDE) are calculated for isopleths moving away from the detonation point for typical release scenarios. Population is estimated within the TEDE zones using Euclidean distances between zip code polygon centroids generated in ArcGIS version 9.1 with distance decay determined by regression analysis to apportion origin-destination pairs to a population count and density matrix on a spatial basis for daytime and night-time release scenarios. (authors)

  20. Do migratory or demographic disruptions rule the population impact of pollution in spatial networks?

    Science.gov (United States)

    Chaumot, A; Charles, S; Flammarion, P; Auger, P

    2003-12-01

    Ecotoxicology supplies environmental quality criteria mainly based on the potential effects of contaminants on demographic rates of natural populations. Possible impacts through pollutant-induced disruptions of spatial behaviors are totally neglected. Should it be significant to take into account this "second way"? We developed the example of a hypothetical brown trout population living in a river network. We analyzed how behaviors of toxic avoidance or attraction during the spawning migration alter the impact of pollution. Attraction behaviors basically enhanced the bad effect of pollution. More interesting, avoidance behaviors can weakly lift the asymptotic population growth rate, while if there is density-dependent effects on recruitment, pollutant avoidance can actually lead to a substantial drop in equilibrium size. Our model allowed comparing the relative significance of migratory and demographic disruptions for explaining the population impacts of pollution; we thus stress on the need of increasing efforts to develop knowledge relative to toxicant-induced spatial behaviors and to integrate such effects in the definition of environmental quality criteria. PMID:14630483

  1. Conservation and the Colombian Amazonian

    International Nuclear Information System (INIS)

    Colombia is a special country in terms of its biological wealth, for it has been classified it as one of the three countries of the world with more biodiversity after Brazil and Indonesia; in the number of species of organisms that they are inside the national limits and it surpasses to gigantic countries as Canada, the United States and Russia. Colombia, for its characteristic biotic, is in the entire world the first one in number of species of birds, of frogs and of orchids and probably second in the world (after Brazil) in the number of species of plants superiors (angiosperms) and species of palms; also, worldwide it is classified to the country among the first ones in the number of species of mammals, reptiles, fish of fresh water and insects. This article, it seeks to discuss the problem of the conservation in the Colombian Amazonian, evaluating the necessities for the future and pointing out some of the current problems that impede a healthy conservation

  2. Spatial heterogeneity of soil chemical properties between Haloxylon persicum and Haloxylon mmodendron populations

    Institute of Scientific and Technical Information of China (English)

    CongJuan LI; Yan LI; Jian MA; LianLian FAN; QinXue WANG

    2010-01-01

    Spatial heterogeneity is a ubiquitous feature in natural ecosystems,especially in arid regions.Different species and their discontinuous distribution,accompanied by varied topographic characteristics,result in soil resources distributed differently in different locations,and present significant spatial heterogeneity in desert ecosystems.In this study,conventional and geostatistical methods were used to identify the heterogeneity of soil chemical properties in two desert populations,Haloxylon persicum Bunge ex Boss.,which dominates on the slopes and tops of sand dunes and Haloxylon ammodendron (C.A.Mey.) Bunge,which inhabits interdunes in the Gurbantunggut Desert of Xinjiang,China.The results showed that soil pH,electrical conductivity (EC),soil organic carbon (SOC),available nitrogen (AN) and available phosphorus (AP) were significantly higher in H.ammodendron populations than that in H.persicum.The coefficient of variation (CV) indicated that (1) most parameters presented a moderate degree of variability (10%<CV<100%) except pH in both plots,(2) the variability of soil pH,EC and AP in H.ammodendron populations was higher than that in H.persicum populations,and (3) SOC and AN in H.ammodendron populations were lower than that in H.persicurn populations.Geostatistical analysis revealed a strong spatial dependence (Co/(Co+C)<25%) within the distance of ranges for all tested parameters in both plots.The Kriging-interpolated figures showed that the soil spatial distribution was correlated with the vegetation distribution,individual size of plants,and the topographic features,especially with the plants nearest to sampling points and the topographic features.In each plot,soil EC,SOC,AN and AP presented similar distributions,and fertile islands and salt islands occurred in both plots but did not affect every individual plant,since the sampling distance was larger than the size of such fertile islands.The results of topographic effects on soil heterogeneity suggested

  3. Spatial heterogeneity of soil chemical properties between Haloxylon persicum and Haloxylon ammodendron populations

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Spatial heterogeneity is a ubiquitous feature in natural ecosystems, especially in arid regions. Different species and their discontinuous distribution, accompanied by varied topographic characteristics, result in soil resources distributed differently in different locations, and present significant spatial heterogeneity in desert ecosystems. In this study, conventional and geostatistical methods were used to identify the heterogeneity of soil chemical properties in two desert populations, Haloxylon persicum Bunge ex Boss., which dominates on the slopes and tops of sand dunes and Haloxylon ammodendron (C. A. Mey.) Bunge, which inhabits interdunes in the Gurbantunggut Desert of Xinjiang, China. The results showed that soil pH, electrical conductivity (EC), soil organic carbon (SOC), available nitrogen (AN) and available phosphorus (AP) were significantly higher in H. ammodendron populations than that in H. persicum. The coefficient of variation (CV) indicated that (1) most parameters presented a moderate degree of variability (10% < CV < 100%) except pH in both plots, (2) the variability of soil pH, EC and AP in H. ammodendron populations was higher than that in H. persicum populations, and (3) SOC and AN in H. ammodendron populations were lower than that in H. persicum populations. Geostatistical analysis revealed a strong spatial dependence (C0/(C0+C) < 25%) within the distance of ranges for all tested parameters in both plots. The Kriging-interpolated figures showed that the soil spatial distribution was correlated with the vegetation distribution, individual size of plants, and the topographic features, especially with the plants nearest to sampling points and the topographic features. In each plot, soil EC, SOC, AN and AP presented similar distributions, and fertile islands and salt islands occurred in both plots but did not affect every individual plant, since the sampling distance was larger than the size of such fertile islands. The results of topographic

  4. Spatial concentration of population in Serbia 1981-2011 measured with the Hoover index

    Directory of Open Access Journals (Sweden)

    Šantić Danica

    2014-01-01

    Full Text Available Population distribution reflects the integrity of natural, social, economic and historical factors of the geospace, relevant both for fundamental and applied research. Complex spatial structure of the contemporary distribution of population in the world, and Serbia as well, during history was determined by human migrations of complex scope and determinants. The aim of this paper was to describe and analyze the geographical redistribution of the population by using the Hoover index as a measure of the redistribution. This measure was introduced by Edgar Hoover in 1936 and it has been widely used in geography. By computing this index, we can allocate the region of population concentration and deconcentration in Serbia. General conceptual framework of concentration and dispersion of population at different geographical levels is presented here. These differences in the achieved level of concentration in Serbia are correlated with the historical development of population, transition from an agrarian into industrial society, and process of urbanization and migration in the last sixty years.

  5. Spatial Pattern and Variation in Literacy among the Scheduled Castes Population in the Brahmaputra Valley, Assam

    Directory of Open Access Journals (Sweden)

    Dr Momita Goswami Barooah

    2014-06-01

    Full Text Available Scheduled Caste (SC population constitutes a sizeable portion of the total population of Assam accounting for 6.32 per cent according to the 2011 Census. They comprise a socially backward class in the Indian society—downtrodden illiterate people of the Indian social fabric. Literacy and educational attainment are considered the hallmark of a modern society. The traits of the modern society, such as, industrialisation, modernisation and urbanisation are closely associated with the level of literacy and education. In the middle part of the 20th century, the literacy rate among them was very low. However, in the later part of the 20th century and in the current millennium due to the developmental measures implemented by both the Central as well as State Governments of India and due to the influence of mass media, there has been a change in the pattern of literacy. The literacy rate of the SC population in the Brahmaputra Valley, Assam was 66.34 per cent in 2011 against 61.15 per cent for general population, which is slightly lower than the SC population in the Valley. The study of the pattern of literacy among various social groups of SCs in the study area provides an insight into the socio-economic situations. An attempt has been made in this paper to analyse the spatial pattern of literacy and its variations among the scheduled caste population in the Brahmaputra Valley, Assam.

  6. Hyperdominance in Amazonian forest carbon cycling

    OpenAIRE

    Fauset, Sophie; Johnson, Michelle O.; Gloor, Manuel; Baker, Timothy R.; Monteagudo M., Abel; Brienen, Roel J.W.; Feldpausch, Ted R.; Lopez-Gonzalez, Gabriela; Malhi, Yadvinder; Ter Steege, Hans; Pitman, Nigel C. A.; Baraloto, Christopher; Engel,Julien; Petronelli, Pascal; Andrade, Ana

    2015-01-01

    While Amazonian forests are extraordinarily diverse, the abundance of trees is skewed strongly towards relatively few â € hyperdominantâ €™ species. In addition to their diversity, Amazonian trees are a key component of the global carbon cycle, assimilating and storing more carbon than any other ecosystem on Earth. Here we ask, using a unique data set of 530 forest plots, if the functions of storing and producing woody carbon are concentrated in a small number of tree species, whether the mos...

  7. Amazonian indigenous settlement and local development in Pastaza, Ecuador

    Directory of Open Access Journals (Sweden)

    Ruth I. Arias-Gutiérrez

    2016-07-01

    Full Text Available In six Amazonian indigenous communities that call to their selves as membership of nación Kichwa, located in Pastaza province, in Ecuador, it is analyzed the process of inhabitation, population characteristics, how much the territory is enough for food requirements for the indigenous families, and their use of land, to determine important factors to improve strategies for local sustainable development. It is considered important because Ecuador has constitutional protection for plural ethnicity and it is looking for improving a new productivity matrix that let down extraction and contamination and raise another matrix based on knowledge and richness from natural renewable resources. Survey used statistics information, qualitative analysis around reality in process, participant research, documentary analysis, oral history and surveys to leadership and family`s chiefs. Results confirm that communities hold standing their identity and knowledge systems of the Amazonian environment, whose conservation they need. Those are factors to be included in local development strategies that let people become safe from effects of extractives activities that are dangerous for culture and environment, in the geographic and biological diversity of the high Ecuadorian Amazonia.

  8. Spatially explicit inference for open populations: estimating demographic parameters from camera-trap studies

    Science.gov (United States)

    Gardner, Beth; Reppucci, Juan; Lucherini, Mauro; Royle, J. Andrew

    2010-01-01

    We develop a hierarchical capture–recapture model for demographically open populations when auxiliary spatial information about location of capture is obtained. Such spatial capture–recapture data arise from studies based on camera trapping, DNA sampling, and other situations in which a spatial array of devices records encounters of unique individuals. We integrate an individual-based formulation of a Jolly-Seber type model with recently developed spatially explicit capture–recapture models to estimate density and demographic parameters for survival and recruitment. We adopt a Bayesian framework for inference under this model using the method of data augmentation which is implemented in the software program WinBUGS. The model was motivated by a camera trapping study of Pampas cats Leopardus colocolo from Argentina, which we present as an illustration of the model in this paper. We provide estimates of density and the first quantitative assessment of vital rates for the Pampas cat in the High Andes. The precision of these estimates is poor due likely to the sparse data set. Unlike conventional inference methods which usually rely on asymptotic arguments, Bayesian inferences are valid in arbitrary sample sizes, and thus the method is ideal for the study of rare or endangered species for which small data sets are typical.

  9. Spatial Modeling of Indian Agriculture, Economic Activity and Population under Climate Change

    Science.gov (United States)

    McCord, G. C.

    2010-12-01

    We present a spatial model of economic activity and human population built on physical geography that takes particular account of its effects through agricultural productivity and transport costs for trade. A major component of this work is an agricultural model, driven in part by high-resolution climate data and model output. We put forward India as the initial region for this modeling work; India is a relatively data-rich country, it exhibits significant within-country spatial and temporal variation in agricultural productivity, urbanization rates, and population growth rates, and the climate dynamics of the monsoon are well-studied and expected to change on decadal time scales. Agricultural productivity is modeled as a function of soil, climate, and technology variables. Farmers locate optimally given varying geography and transport costs; in turn, food availability defines urbanization rates and economic activity in non-agricultural sectors. This “social system” integrated assessment model is a step towards a valuable policy tool, but requires a significant mobilization of data and a grid-cell-level system of equations to describe the underlying dynamics of the model. We test against past trends of social-natural system progression in demography, human location, income, food production, etc., and argue that the model could be used to assess future trends under varying climate change scenarios, and eventually serve to model feedbacks through effects on migration, population growth rates, or economic activity.

  10. Spatial and Temporal Changes of Floating Population in China Between 1990 and 2000

    Institute of Scientific and Technical Information of China (English)

    LIU Chen; Kuninori OTSUBO; WANG Qinxue; Toshiaki ICHINOSE; Sadao ISHIMURA

    2007-01-01

    By studying the county-level census data of 1990 and 2000, we analyzed the spatial and temporal changes in the floating population in China between 1990 and 2000. The results of the analysis revealed the following characteristics. First, the spatial distribution of the migrants (referred to as 'floaters' in this paper) became increasingly concentrated in the cities during the 1990s. Second, the number of floaters increased rapidly during this period, and the area in which the floaters settled expanded quickly into four population explosion belts: the coast, the Changjiang River Delta, the Beijing-Guangzhou Railway and national border belts. Third, the number of inter-province floaters increased rapidly and exceeded that of intra-province floaters in the 1990s. In addition, to obtain a quantitative relationship between the number of floaters and 10 socio-economic variables by using statistical methods and also to find the chiefly important pulling factors of the migration destination, the authors selected approximately 100 cities with the largest population of floaters. Consequently, we found that four factors GDP, passenger trips per 10,000 persons, per capita GDP and foreign direct investment could provide an explanation for 83.7% of the number of floaters in 2000. The GDP showed the highest correlation with the number of floaters, suggesting that a highly developed economy is the most important factor that attracts floaters. Furthermore, a fairly close relationship between the number of floaters and the GDP was also found in 2000 for all the counties.

  11. Graph theory as a proxy for spatially explicit population models in conservation planning.

    Science.gov (United States)

    Minor, Emily S; Urban, Dean L

    2007-09-01

    Spatially explicit population models (SEPMs) are often considered the best way to predict and manage species distributions in spatially heterogeneous landscapes. However, they are computationally intensive and require extensive knowledge of species' biology and behavior, limiting their application in many cases. An alternative to SEPMs is graph theory, which has minimal data requirements and efficient algorithms. Although only recently introduced to landscape ecology, graph theory is well suited to ecological applications concerned with connectivity or movement. This paper compares the performance of graph theory to a SEPM in selecting important habitat patches for Wood Thrush (Hylocichla mustelina) conservation. We use both models to identify habitat patches that act as population sources and persistent patches and also use graph theory to identify patches that act as stepping stones for dispersal. Correlations of patch rankings were very high between the two models. In addition, graph theory offers the ability to identify patches that are very important to habitat connectivity and thus long-term population persistence across the landscape. We show that graph theory makes very similar predictions in most cases and in other cases offers insight not available from the SEPM, and we conclude that graph theory is a suitable and possibly preferable alternative to SEPMs for species conservation in heterogeneous landscapes. PMID:17913139

  12. Spatially resolved stellar population parameters in the BCGs of two fossil groups

    CERN Document Server

    Proctor, Robert N; Eigenthaler, Paul

    2014-01-01

    We report the results of Gemini/GMOS long-slit spectroscopic observations along the major and minor axes of the central galaxies in two fossil groups, SDSS J073422.21+265133.9 and SDSS J075828.11+374711.8 (the NGC 2484 group). Spatially resolved kinematics and stellar population parameters (ages, metallicities and $\\alpha$-element abundance ratios) derived using ~20 Lick indices are presented. Despite remarkable similarities in their morphologies, photometric properties (luminosity and colour) and kinematics, the two galaxies exhibit significantly different stellar population parameters. SDSS J073422.21+265133.9 exhibits a strong metallicity gradient (Delta[Z/H]/Delta R ~ -0.4) all the way into the centre of the galaxy. It also exhibits an age profile that suggest a relatively recent, centrally concentrated burst of star formation superimposed on an older, more spatially extended population. NGC 2484, a well known X-ray AGN, exhibits a flat core-like structure in its metallicity gradient, but no detectable ag...

  13. An Updating System for the Gridded Population Database of China Based on Remote Sensing, GIS and Spatial Database Technologies

    Directory of Open Access Journals (Sweden)

    Xiaohuan Yang

    2009-02-01

    Full Text Available The spatial distribution of population is closely related to land use and land cover (LULC patterns on both regional and global scales. Population can be redistributed onto geo-referenced square grids according to this relation. In the past decades, various approaches to monitoring LULC using remote sensing and Geographic Information Systems (GIS have been developed, which makes it possible for efficient updating of geo-referenced population data. A Spatial Population Updating System (SPUS is developed for updating the gridded population database of China based on remote sensing, GIS and spatial database technologies, with a spatial resolution of 1 km by 1 km. The SPUS can process standard Moderate Resolution Imaging Spectroradiometer (MODIS L1B data integrated with a Pattern Decomposition Method (PDM and an LULC-Conversion Model to obtain patterns of land use and land cover, and provide input parameters for a Population Spatialization Model (PSM. The PSM embedded in SPUS is used for generating 1 km by 1 km gridded population data in each population distribution region based on natural and socio-economic variables. Validation results from finer township-level census data of Yishui County suggest that the gridded population database produced by the SPUS is reliable.

  14. The CALIFA survey across the Hubble sequence: Spatially resolved stellar population properties in galaxies

    CERN Document Server

    Delgado, R M González; Pérez, E; Fernandes, R Cid; de Amorim, A L; Cortijo-Ferrero, C; Lacerda, E A D; Fernández, R López; Vale-Asari, N; Sánchez, S F; Mollá, M; Ruiz-Lara, T; Sánchez-Blázquez, P; Walcher, C J; Alves, J; Aguerri, J A L; Bekeraité, S; Bland-Hawthorn, J; Galbany, L; Gallazzi, A; Husemann, B; Iglesias-Páramo, J; Kalinova, V; López-Sánchez, A R; Marino, R A; Márquez, I; Masegosa, J; Mast, D; Méndez-Abreu, J; Mendoza, A; del Olmo, A; Pérez, I; Quirrenbach, A; Zibetti, S

    2015-01-01

    This paper characterizes the radial structure of stellar population properties of galaxies in the nearby universe, based on 300 galaxies from the CALIFA survey. The sample covers a wide range of Hubble types, and galaxy stellar mass. We apply the spectral synthesis techniques to recover the stellar mass surface density, stellar extinction, light and mass-weighted ages, and mass-weighted metallicity, for each spatial resolution element in our target galaxies. To study mean trends with overall galaxy properties, the individual radial profiles are stacked in seven bins of galaxy morphology. We confirm that more massive galaxies are more compact, older, more metal rich, and less reddened by dust. Additionally, we find that these trends are preserved spatially with the radial distance to the nucleus. Deviations from these relations appear correlated with Hubble type: earlier types are more compact, older, and more metal rich for a given mass, which evidences that quenching is related to morphology, but not driven ...

  15. Spatial and temporal population genetic variation and structure of Nothotsuga longibracteata (Pinaceae, a relic conifer species endemic to subtropical China

    Directory of Open Access Journals (Sweden)

    Yingjun Qiu

    2013-01-01

    Full Text Available Nothotsuga longibracteata, a relic and endangered conifer species endemic to subtropical China, was studied for examining the spatial-temporal population genetic variation and structure to understand the historical biogeographical processes underlying the present geographical distribution. Ten populations were sampled over the entire natural range of the species for spatial analysis, while three key populations with large population sizes and varied age structure were selected for temporal analyses using both nuclear microsatellites (nSSR and chloroplast microsatellites (cpSSR. A recent bottleneck was detected in the natural populations of N. longibracteata. The spatial genetic analysis showed significant population genetic differentiation across its total geographical range. Notwithstanding, the temporal genetic analysis revealed that the level of genetic diversity between different age class subpopulations remained constant over time. Eleven refugia of the Last Glacial Maximum were identified, which deserve particular attention for conservation management.

  16. Effects of Sand Dune Stabilization on the Spatial Pattern of Artemisia ordosica Population in Mu Us Desert, Northwest China

    Science.gov (United States)

    Zhang, Jiachen; Zhang, Yuqing; Fan, Dongqing; Qin, Shugao; Jia, Xin; Wu, Bin; Chen, Dong; Gao, Hao; Zhu, Linfeng

    2015-01-01

    Vegetation patterns are strongly influenced by sand mobility in desert ecosystems. However, little is known about the spatial patterns of Artemisia ordosica, a dominant shrub in the Mu Us desert of Northwest China, in relation to sand fixation. The aim of this study was to investigate and contrast the effects of sand dune stabilization on the population and spatial distribution of this desert shrub. Spatial autocorrelation, semi-variance analysis, and point-pattern analysis were used jointly in this study to investigate the spatial patterns of A. ordosica populations on dunes in Yanchi County of Ningxia, China. The results showed that the spatial autocorrelation and spatial heterogeneity declined gradually, and the distance between the clustered individuals shortened following sand dune fixation. Seedlings were more aggregated than adults in all stage of dune stabilization, and both were more aggregated on shifting sand dunes separately. Spatial associations of the seedlings with the adults were mostly positive at distances of 0–5 m in shifting sand dunes, and the spatial association changed from positive to neutral in semi-fixed sand dunes. The seedlings were spaced in an almost random pattern around the adults, and their distances from the adults did not seem to affect their locations in semi-fixed sand dunes. Furthermore, spatial associations of the seedlings with the adults were negative in the fixed sand dune. These findings demonstrate that sand stabilization is an important factor affecting the spatial patterns of A. ordosica populations in the Mu Us desert. These findings suggest that, strong association between individuals may be the mechanism to explain the spatial pattern formation at preliminary stage of dune fixation. Sand dune stabilization can change the spatial pattern of shrub population by weakening the spatial association between native shrub individuals, which may affect the development direction of desert shrubs. PMID:26102584

  17. Population evolution in mutualistic Lotka-Volterra system with spatial diffusion

    Science.gov (United States)

    Wang, Mao-Xiang; Ma, Yu-Qiang

    2014-02-01

    We consider the population dynamics of two species described by the mutualistic Lotka-Volterra model with a +/+ interaction in the presence of spatial diffusions. The results demonstrate that diffusion does not affect the system’s stability but it brings two situations: one is a win-win situation where both species propagate with the same largest speed; in the other situation the aggressive species has two propagating wave fronts and the other species travels with a single slow wave front. Our model may help to understand the evolution of mutualism.

  18. Spatial population structure of the Neotropical tiger catfish Pseudoplatystoma metaense: skull and otolith shape variation.

    Science.gov (United States)

    Pérez, A; Fabré, N N

    2013-05-01

    Using geometric morphometrics, the skull and otolith of tiger catfish Pseudoplatystoma metaense were analysed to identify population structure in tributaries of the Apure River (i.e. the Sarare, Caparo, Guanare, Portuguesa and San Carlos Rivers) in the Orinoco basin, Venezuela. The analyses show uniformity in skull and otolith shapes of P. metaense within and among four tributaries, with only the Caparo River showing significant differences. Within the Apure basin, the stock of P. metaense was differentiated through spawning, refuge and nursery areas. This study concludes that populations of P. metaense from each major tributary in the Orinoco basin should be considered as part of a metapopulation system for management purposes. Human disturbances in the catchment have directly reduced the spawning areas available to this species, decreased the total biomass and changed the spatial distribution of spawning areas. PMID:23639147

  19. Role of intraspecific competition in the coexistence of mobile populations in spatially extended ecosystems

    Science.gov (United States)

    Yang, Rui; Wang, Wen-Xu; Lai, Ying-Cheng; Grebogi, Celso

    2010-06-01

    Evolutionary-game based models of nonhierarchical, cyclically competing populations have become paradigmatic for addressing the fundamental problem of species coexistence in spatially extended ecosystems. We study the role of intraspecific competition in the coexistence and find that the competition can strongly promote the coexistence for high individual mobility in the sense that stable coexistence can arise in parameter regime where extinction would occur without the competition. The critical value of the competition rate beyond which the coexistence is induced is found to be independent of the mobility. We derive a theoretical model based on nonlinear partial differential equations to predict the critical competition rate and the boundaries between the coexistence and extinction regions in a relevant parameter space. We also investigate pattern formation and well-mixed spatiotemporal population dynamics to gain further insights into our findings.

  20. Characterising the spatial dynamics of sympatric Aedes aegypti and Aedes albopictus populations in the Philippines

    Directory of Open Access Journals (Sweden)

    Jennifer Duncombe

    2013-11-01

    Full Text Available Entomological surveillance and control are essential to the management of dengue fever (DF. Hence, understanding the spatial and temporal patterns of DF vectors, Aedes (Stegomyia aegypti (L. and Ae. (Stegomyia albopictus (Skuse, is paramount. In the Philippines, resources are limited and entomological surveillance and control are generally commenced during epidemics, when transmission is difficult to control. Recent improvements in spatial epidemiological tools and methods offer opportunities to explore more efficient DF surveillance and control solutions: however, there are few examples in the literature from resource-poor settings. The objectives of this study were to: (i explore spatial patterns of Aedes populations and (ii predict areas of high and low vector density to inform DF control in San Jose village, Muntinlupa city, Philippines. Fortnightly, adult female Aedes mosquitoes were collected from 50 double-sticky ovitraps (SOs located in San Jose village for the period June-November 2011. Spatial clustering analysis was performed to identify high and low density clusters of Ae. aegypti and Ae. albopictus mosquitoes. Spatial autocorrelation was assessed by examination of semivariograms, and ordinary kriging was undertaken to create a smoothed surface of predicted vector density in the study area. Our results show that both Ae. aegypti and Ae. albopictus were present in San Jose village during the study period. However, one Aedes species was dominant in a given geographic area at a time, suggesting differing habitat preferences and interspecies competition between vectors. Density maps provide information to direct entomological control activities and advocate the development of geographically enhanced surveillance and control systems to improve DF management in the Philippines.

  1. Individual spatial aggregation correlates with between-population variation in fine-scale genetic structure of Silene ciliata (Caryophyllaceae).

    Science.gov (United States)

    Lara-Romero, C; García-Fernández, A; Robledo-Arnuncio, J J; Roumet, M; Morente-López, J; López-Gil, A; Iriondo, J M

    2016-05-01

    Fine-scale genetic structure (FSGS) can vary among populations within species depending on multiple demographic and environmental factors. Theoretical models predict that FSGS should decrease in high-density populations and increase in populations where individuals are spatially aggregated. However, few empirical studies have compared FSGS between populations with different degrees of individual spatial aggregation and microhabitat heterogeneity. In this work, we studied the relationship between spatial and genetic structure in five populations of alpine specialist Silene ciliata Poiret (Caryophyllaceae). We mapped all individuals in each population and genotyped 96 of them using 10 microsatellite markers. We found significant FSGS consistent with an isolation-by-distance process in three of the five populations. The intensity of FSGS was positively associated with individual spatial aggregation. However, no association was found between FSGS and global population density or microhabitat heterogeneity. Overall, our results support theoretical studies indicating that stronger spatial aggregation tends to increase the magnitude of FSGS. They also highlight the relevance of characterizing local plant distribution and microhabitat to better understand the mechanisms that generate intraspecific variation in FSGS across landscapes. PMID:26604191

  2. Regional variations in spatial structure of nightlights, population density and fossil-fuel CO2 emissions

    International Nuclear Information System (INIS)

    We evaluate the joint use of satellite-observed intensity of urban nightlights and census-based population density data as constraints on the spatial structure of CO2 emissions from fossil fuels. Findings are: (1) the probability that population density exceeds a given value follows a power-law distribution over two orders of magnitude of population density, encompassing the 40% of the global population at the highest densities. (2) The corresponding probability distribution for nightlights intensity also follows a power-law, departing near instrumental saturation. (3) Assuming that the true nightlights intensity distribution follows the power-law above instrumental saturation, we obtain a correction for saturation errors in the nightlights data. The amplification of nightlights intensity required to correct for saturation errors is estimated to be a factor of 1.15-1.23 globally and much greater in regions with high nightlights intensities. (4) Correcting for saturation, we observe clear empirical relationships between nightlights intensity and areal densities of energy consumption, fossil-fuel emissions and economic activity, holding throughout the development spectrum. (5) We indicate how these relationships underpin a fossil-fuel data assimilation system (FFDAS) for estimating fossil-fuel CO2 emissions.

  3. From individual spiking neurons to population behavior: Systematic elimination of short-wavelength spatial modes

    Science.gov (United States)

    Steyn-Ross, Moira L.; Steyn-Ross, D. A.

    2016-02-01

    Mean-field models of the brain approximate spiking dynamics by assuming that each neuron responds to its neighbors via a naive spatial average that neglects local fluctuations and correlations in firing activity. In this paper we address this issue by introducing a rigorous formalism to enable spatial coarse-graining of spiking dynamics, scaling from the microscopic level of a single type 1 (integrator) neuron to a macroscopic assembly of spiking neurons that are interconnected by chemical synapses and nearest-neighbor gap junctions. Spiking behavior at the single-neuron scale ℓ ≈10 μ m is described by Wilson's two-variable conductance-based equations [H. R. Wilson, J. Theor. Biol. 200, 375 (1999), 10.1006/jtbi.1999.1002], driven by fields of incoming neural activity from neighboring neurons. We map these equations to a coarser spatial resolution of grid length B ℓ , with B ≫1 being the blocking ratio linking micro and macro scales. Our method systematically eliminates high-frequency (short-wavelength) spatial modes q ⃗ in favor of low-frequency spatial modes Q ⃗ using an adiabatic elimination procedure that has been shown to be equivalent to the path-integral coarse graining applied to renormalization group theory of critical phenomena. This bottom-up neural regridding allows us to track the percolation of synaptic and ion-channel noise from the single neuron up to the scale of macroscopic population-average variables. Anticipated applications of neural regridding include extraction of the current-to-firing-rate transfer function, investigation of fluctuation criticality near phase-transition tipping points, determination of spatial scaling laws for avalanche events, and prediction of the spatial extent of self-organized macrocolumnar structures. As a first-order exemplar of the method, we recover nonlinear corrections for a coarse-grained Wilson spiking neuron embedded in a network of identical diffusively coupled neurons whose chemical synapses have

  4. From individual spiking neurons to population behavior: Systematic elimination of short-wavelength spatial modes.

    Science.gov (United States)

    Steyn-Ross, Moira L; Steyn-Ross, D A

    2016-02-01

    Mean-field models of the brain approximate spiking dynamics by assuming that each neuron responds to its neighbors via a naive spatial average that neglects local fluctuations and correlations in firing activity. In this paper we address this issue by introducing a rigorous formalism to enable spatial coarse-graining of spiking dynamics, scaling from the microscopic level of a single type 1 (integrator) neuron to a macroscopic assembly of spiking neurons that are interconnected by chemical synapses and nearest-neighbor gap junctions. Spiking behavior at the single-neuron scale ℓ≈10μm is described by Wilson's two-variable conductance-based equations [H. R. Wilson, J. Theor. Biol. 200, 375 (1999)], driven by fields of incoming neural activity from neighboring neurons. We map these equations to a coarser spatial resolution of grid length Bℓ, with B≫1 being the blocking ratio linking micro and macro scales. Our method systematically eliminates high-frequency (short-wavelength) spatial modes q(->) in favor of low-frequency spatial modes Q(->) using an adiabatic elimination procedure that has been shown to be equivalent to the path-integral coarse graining applied to renormalization group theory of critical phenomena. This bottom-up neural regridding allows us to track the percolation of synaptic and ion-channel noise from the single neuron up to the scale of macroscopic population-average variables. Anticipated applications of neural regridding include extraction of the current-to-firing-rate transfer function, investigation of fluctuation criticality near phase-transition tipping points, determination of spatial scaling laws for avalanche events, and prediction of the spatial extent of self-organized macrocolumnar structures. As a first-order exemplar of the method, we recover nonlinear corrections for a coarse-grained Wilson spiking neuron embedded in a network of identical diffusively coupled neurons whose chemical synapses have been disabled. Intriguingly

  5. Estimating Temporal Trend in the Presence of Spatial Complexity: A Bayesian Hierarchical Model for a Wetland Plant Population Undergoing Restoration

    OpenAIRE

    Rodhouse, Thomas J.; Kathryn M Irvine; Vierling, Kerri T.; Lee A Vierling

    2011-01-01

    Monitoring programs that evaluate restoration and inform adaptive management are important for addressing environmental degradation. These efforts may be well served by spatially explicit hierarchical approaches to modeling because of unavoidable spatial structure inherited from past land use patterns and other factors. We developed Bayesian hierarchical models to estimate trends from annual density counts observed in a spatially structured wetland forb (Camassia quamash [camas]) population f...

  6. The Tsimane’ Amazonian Panel Study (TAPS): Nine years (2002-2010) of annual data available to the public

    Science.gov (United States)

    Leonard, William R.; Reyes-García, Victoria; Tanner, Susan; Rosinger, Asher; Schultz, Alan; Vadez, Vincent; Zhang, Rebecca; Godoy, Ricardo

    2016-01-01

    This brief communication contains a description of the 2002-2010 annual panel collected by the Tsimane’ Amazonian Panel Study team. The study took place among the Tsimane’, a native Amazonian society of forager-horticulturalists. The team tracked a wide range of socio-economic and anthropometric variables from all residents (633 adults ≥16 years; 820 children) in 13 villages along the Maniqui River, department of Beni. The panel is ideally suited to examine how market exposure and modernization affect the well-being of a highly autarkic population and to examine human growth in a non-Western rural setting. PMID:26280812

  7. Spatial and temporal country-wide survey of temephos resistance in Brazilian populations of Aedes aegypti.

    Science.gov (United States)

    Chediak, Mateus; G Pimenta, Fabiano; Coelho, Giovanini E; Braga, Ima A; Lima, José Bento P; Cavalcante, Karina Ribeiro Lj; Sousa, Lindemberg C de; Melo-Santos, Maria Alice V de; Macoris, Maria de Lourdes da G; Araújo, Ana Paula de; Ayres, Constância Flávia J; Andrighetti, Maria Teresa M; Gomes, Ricristhi Gonçalves de A; Campos, Kauara B; Guedes, Raul Narciso C

    2016-05-01

    The organophosphate temephos has been the main insecticide used against larvae of the dengue and yellow fever mosquito (Aedes aegypti) in Brazil since the mid-1980s. Reports of resistance date back to 1995; however, no systematic reports of widespread temephos resistance have occurred to date. As resistance investigation is paramount for strategic decision-making by health officials, our objective here was to investigate the spatial and temporal spread of temephos resistance in Ae. aegypti in Brazil for the last 12 years using discriminating temephos concentrations and the bioassay protocols of the World Health Organization. The mortality results obtained were subjected to spatial analysis for distance interpolation using semi-variance models to generate maps that depict the spread of temephos resistance in Brazil since 1999. The problem has been expanding. Since 2002-2003, approximately half the country has exhibited mosquito populations resistant to temephos. The frequency of temephos resistance and, likely, control failures, which start when the insecticide mortality level drops below 80%, has increased even further since 2004. Few parts of Brazil are able to achieve the target 80% efficacy threshold by 2010/2011, resulting in a significant risk of control failure by temephos in most of the country. The widespread resistance to temephos in Brazilian Ae. aegypti populations greatly compromise effective mosquito control efforts using this insecticide and indicates the urgent need to identify alternative insecticides aided by the preventive elimination of potential mosquito breeding sites. PMID:27143489

  8. Estimating population density and connectivity of American mink using spatial capture-recapture.

    Science.gov (United States)

    Fuller, Angela K; Sutherland, Chris S; Royle, J Andrew; Hare, Matthew P

    2016-06-01

    Estimating the abundance or density of populations is fundamental to the conservation and management of species, and as landscapes become more fragmented, maintaining landscape connectivity has become one of the most important challenges for biodiversity conservation. Yet these two issues have never been formally integrated together in a model that simultaneously models abundance while accounting for connectivity of a landscape. We demonstrate an application of using capture-recapture to develop a model of animal density using a least-cost path model for individual encounter probability that accounts for non-Euclidean connectivity in a highly structured network. We utilized scat detection dogs (Canis lupus familiaris) as a means of collecting non-invasive genetic samples of American mink (Neovison vison) individuals and used spatial capture-recapture models (SCR) to gain inferences about mink population density and connectivity. Density of mink was not constant across the landscape, but rather increased with increasing distance from city, town, or village centers, and mink activity was associated with water. The SCR model allowed us to estimate the density and spatial distribution of individuals across a 388 km² area. The model was used to investigate patterns of space usage and to evaluate covariate effects on encounter probabilities, including differences between sexes. This study provides an application of capture-recapture models based on ecological distance, allowing us to directly estimate landscape connectivity. This approach should be widely applicable to provide simultaneous direct estimates of density, space usage, and landscape connectivity for many species. PMID:27509753

  9. Spatial and temporal country-wide survey of temephos resistance in Brazilian populations of Aedes aegypti

    Science.gov (United States)

    Chediak, Mateus; G Pimenta, Fabiano; Coelho, Giovanini E; Braga, Ima A; Lima, José Bento P; Cavalcante, Karina Ribeiro LJ; de Sousa, Lindemberg C; de Melo-Santos, Maria Alice V; Macoris, Maria de Lourdes da G; de Araújo, Ana Paula; Ayres, Constância Flávia J; Andrighetti, Maria Teresa M; Gomes, Ricristhi Gonçalves de A; Campos, Kauara B; Guedes, Raul Narciso C

    2016-01-01

    The organophosphate temephos has been the main insecticide used against larvae of the dengue and yellow fever mosquito (Aedes aegypti) in Brazil since the mid-1980s. Reports of resistance date back to 1995; however, no systematic reports of widespread temephos resistance have occurred to date. As resistance investigation is paramount for strategic decision-making by health officials, our objective here was to investigate the spatial and temporal spread of temephos resistance in Ae. aegypti in Brazil for the last 12 years using discriminating temephos concentrations and the bioassay protocols of the World Health Organization. The mortality results obtained were subjected to spatial analysis for distance interpolation using semi-variance models to generate maps that depict the spread of temephos resistance in Brazil since 1999. The problem has been expanding. Since 2002-2003, approximately half the country has exhibited mosquito populations resistant to temephos. The frequency of temephos resistance and, likely, control failures, which start when the insecticide mortality level drops below 80%, has increased even further since 2004. Few parts of Brazil are able to achieve the target 80% efficacy threshold by 2010/2011, resulting in a significant risk of control failure by temephos in most of the country. The widespread resistance to temephos in Brazilian Ae. aegypti populations greatly compromise effective mosquito control efforts using this insecticide and indicates the urgent need to identify alternative insecticides aided by the preventive elimination of potential mosquito breeding sites. PMID:27143489

  10. Connecting multiple spatial scales to decode the population activity of grid cells.

    Science.gov (United States)

    Stemmler, Martin; Mathis, Alexander; Herz, Andreas V M

    2015-12-01

    Mammalian grid cells fire when an animal crosses the points of an imaginary hexagonal grid tessellating the environment. We show how animals can navigate by reading out a simple population vector of grid cell activity across multiple spatial scales, even though neural activity is intrinsically stochastic. This theory of dead reckoning explains why grid cells are organized into discrete modules within which all cells have the same lattice scale and orientation. The lattice scale changes from module to module and should form a geometric progression with a scale ratio of around 3/2 to minimize the risk of making large-scale errors in spatial localization. Such errors should also occur if intermediate-scale modules are silenced, whereas knocking out the module at the smallest scale will only affect spatial precision. For goal-directed navigation, the allocentric grid cell representation can be readily transformed into the egocentric goal coordinates needed for planning movements. The goal location is set by nonlinear gain fields that act on goal vector cells. This theory predicts neural and behavioral correlates of grid cell readout that transcend the known link between grid cells of the medial entorhinal cortex and place cells of the hippocampus. PMID:26824061

  11. The spatial distribution of threats to plant species with extremely small populations

    Science.gov (United States)

    Wang, Chunjing; Zhang, Jing; Wan, Jizhong; Qu, Hong; Mu, Xianyun; Zhang, Zhixiang

    2016-04-01

    Many biological conservationists take actions to conserve plant species with extremely small populations (PSESP) in China; however, there have been few studies on the spatial distribution of threats to PSESP. Hence, we selected distribution data of PSESP and made a map of the spatial distribution of threats to PSESP in China. First, we used the weight assignment method to evaluate the threat risk to PSESP at both country and county scales. Second, we used a geographic information system to map the spatial distribution of threats to PSESP, and explored the threat factors based on linear regression analysis. Finally, we suggested some effective conservation options. We found that the PSESP with high values of protection, such as the plants with high scientific research values and ornamental plants, were threatened by over-exploitation and utilization, habitat fragmentation, and a small sized wild population in broad-leaved forests and bush fallows. We also identified some risk hotspots for PSESP in China. Regions with low elevation should be given priority for ex- and in-situ conservation. Moreover, climate change should be considered for conservation of PSESP. To avoid intensive over-exploitation or utilization and habitat fragmentation, in-situ conservation should be practiced in regions with high temperatures and low temperature seasonality, particularly in the high risk hotspots for PSESP that we proposed. Ex-situ conservation should be applied in these same regions, and over-exploitation and utilization of natural resources should be prevented. It is our goal to apply the concept of PSESP to the global scale in the future.

  12. Development of a spatial stochastic multimedia exposure model to assess population exposure at a regional scale

    International Nuclear Information System (INIS)

    Analyzing the relationship between the environment and health has become a major focus of public health efforts in France, as evidenced by the national action plans for health and the environment. These plans have identified the following two priorities: -identify and manage geographic areas where hotspot exposures are a potential risk to human health; and -reduce exposure inequalities. The aim of this study is to develop a spatial stochastic multimedia exposure model for detecting vulnerable populations and analyzing exposure determinants at a fine resolution and regional scale. A multimedia exposure model was developed by INERIS to assess the transfer of substances from the environment to humans through inhalation and ingestion pathways. The RESPIR project adds a spatial dimension by linking GIS (Geographic Information System) to the model. Tools are developed using modeling, spatial analysis and geostatistic methods to build and discretize interesting variables and indicators from different supports and resolutions on a 1-km2 regular grid. We applied this model to the risk assessment of exposure to metals (cadmium, lead and nickel) using data from a region in France (Nord-Pas-de-Calais). The considered exposure pathways include the atmospheric contaminant inhalation and ingestion of soil, vegetation, meat, egg, milk, fish and drinking water. Exposure scenarios are defined for different reference groups (age, dietary properties, and the fraction of food produced locally). The two largest risks correspond to an ancient industrial site (Metaleurop) and the Lille agglomeration. In these areas, cadmium, vegetation ingestion and soil contamination are the principal determinants of the computed risk. -- Highlights: ► We present a multimedia exposure model for mapping environmental disparities. ► We perform a risk assessment on a region of France at a fine scale for three metals. ► We examine exposure determinants and detect vulnerable population. ► The largest

  13. Diverse Early Life-History Strategies in Migratory Amazonian Catfish: Implications for Conservation and Management.

    Directory of Open Access Journals (Sweden)

    Jens C Hegg

    Full Text Available Animal migrations provide important ecological functions and can allow for increased biodiversity through habitat and niche diversification. However, aquatic migrations in general, and those of the world's largest fish in particular, are imperiled worldwide and are often poorly understood. Several species of large Amazonian catfish carry out some of the longest freshwater fish migrations in the world, travelling from the Amazon River estuary to the Andes foothills. These species are important apex predators in the main stem rivers of the Amazon Basin and make up the region's largest fishery. They are also the only species to utilize the entire Amazon Basin to complete their life cycle. Studies indicate both that the fisheries may be declining due to overfishing, and that the proposed and completed dams in their upstream range threaten spawning migrations. Despite this, surprisingly little is known about the details of these species' migrations, or their life history. Otolith microchemistry has been an effective method for quantifying and reconstructing fish migrations worldwide across multiple spatial scales and may provide a powerful tool to understand the movements of Amazonian migratory catfish. Our objective was to describe the migratory behaviors of the three most populous and commercially important migratory catfish species, Dourada (Brachyplatystoma rousseauxii, Piramutaba (Brachyplatystoma vaillantii, and Piraíba (Brachyplatystoma filamentosum. We collected fish from the mouth of the Amazon River and the Central Amazon and used strontium isotope signatures ((87Sr/(86Sr recorded in their otoliths to determine the location of early rearing and subsequent. Fish location was determined through discriminant function classification, using water chemistry data from the literature as a training set. Where water chemistry data was unavailable, we successfully in predicted (87Sr/(86Sr isotope values using a regression-based approach that related

  14. Legacies of Amazonian dark earths on forest composition, structure and dynamics

    OpenAIRE

    Quintero Vallejo, E.M.

    2015-01-01

    Summary Amazonian forest is seen as the archetype of pristine forests, untouched by humans, but this romantic view is far from reality. In recent years, there is increasing evidence of long and extensive landscape modification by humans. Processes of permanent inhabitation, expansion and retreat of human populations have not always been obvious in those ecosystems, leaving sometimes weak and overlooked imprints in the landscape. An example of one of these inconspicuous alterations are the mod...

  15. Biogeography and evolution of Amazonian triatomines (Heteroptera: Reduviidae: implications for Chagas disease surveillance in humid forest ecoregions

    Directory of Open Access Journals (Sweden)

    Fernando Abad-Franch

    2007-10-01

    Full Text Available An ecological-evolutionary classification of Amazonian triatomines is proposed based on a revision of their main contemporary biogeographical patterns. Truly Amazonian triatomines include the Rhodniini, the Cavernicolini, and perhaps Eratyrus and some Bolboderini. The tribe Rhodniini comprises two major lineages (pictipes and robustus. The former gave rise to trans-Andean (pallescens and Amazonian (pictipes species groups, while the latter diversified within Amazonia (robustus group and radiated to neighbouring ecoregions (Orinoco, Cerrado-Caatinga-Chaco, and Atlantic Forest. Three widely distributed Panstrongylus species probably occupied Amazonia secondarily, while a few Triatoma species include Amazonian populations that occur only in the fringes of the region. T. maculata probably represents a vicariant subset isolated from its parental lineage in the Caatinga-Cerrado system when moist forests closed a dry trans-Amazonian corridor. These diverse Amazonian triatomines display different degrees of synanthropism, defining a behavioural gradient from household invasion by adult triatomines to the stable colonisation of artificial structures. Anthropogenic ecological disturbance (driven by deforestation is probably crucial in the onset of the process, but the fact that only a small fraction of species effectively colonises artificial environments suggests a role for evolution at the end of the gradient. Domestic infestation foci are restricted to drier subregions within Amazonia; thus, populations adapted to extremely humid rainforest microclimates may have limited chances of successfully colonising the slightly drier artificial microenvironments. These observations suggest several research avenues, from the use of climate data to map risk areas to the assessment of the synanthropic potential of individual vector species.

  16. The massive star population in M101. II. Spatial variations in the recent star formation history

    International Nuclear Information System (INIS)

    We investigate star formation history (SFH) as a function of radius in M101 using archival Hubble Space Telescope Advanced Camera for Surveys photometry. We derive the SFH from the resolved stellar populations in five 2' wide annuli. Binning the SFH into time frames corresponding to stellar populations traced by Hα, far-ultraviolet, and near-ultraviolet emission, we find that the fraction of stellar populations young enough to contribute in Hα is 15%-35% in the inner regions, compared to less than 5% in the outer regions. This provides a sufficient explanation for the lack of Hα emission at large radii. We also model the blue to red supergiant ratio in our five annuli, examine the effects that a metallicity gradient and variable SFH have on the predicted ratios, and compare to the observed values. We find that the radial behavior of our modeled blue to red supergiant ratios is highly sensitive to both spatial variations in the SFH and metallicity. Incorporating the derived SFH into modeled ratios, we find that we are able to reproduce the observed values at large radii (low metallicity), but at small radii (high metallicity) the modeled and observed ratios are discrepant.

  17. GENETIC AND SPATIAL STRUCTURE OF NATURAL POPULATIONS OF Calophyllum brasiliense Camb. IN GALLERY FOREST

    Directory of Open Access Journals (Sweden)

    Anderson Marcos de Souza

    2007-09-01

    Full Text Available Calophyllum brasiliense Camb. (Clusiaceae is a tree of great ecological plasticity and it is present in different forestphysiognomy. Due to its preference to water-saturated soils, it is considered specialist in habitat, due to this, it occurs frequently inthe riparian forest. In order to access and understand the inter and intrapopulation genetic variability patterns, two populations of C.brasiliense in gallery forest were sampled. The results obtained by isoenzyme electrophoresis analysis showed a high heterozygosityfor this species, equal 0.444 and 0.492. The genetic structure analysis indicated the absence of intra and inter populationsinbreeding ( f = -0.078; F = -0.063. Most of the genetic variability was distributed within the populations ( = 0.14 and the geneflow was low ( m N= 0.83. The coancestry coefficient estimated showed positive spatial structure in small distance classes. Thisinformation is important to programs of conservation genetics in situ and ex situ of the species. Moreover, it is necessary to improvethe preservation and the maintenance of natural populations of C. brasiliense, since this species demonstrates fragility to factors thatput at risk its genetic variability. op

  18. Population genetics of the Eastern Hellbender (Cryptobranchus alleganiensis alleganiensis across multiple spatial scales.

    Directory of Open Access Journals (Sweden)

    Shem D Unger

    Full Text Available Conservation genetics is a powerful tool to assess the population structure of species and provides a framework for informing management of freshwater ecosystems. As lotic habitats become fragmented, the need to assess gene flow for species of conservation management becomes a priority. The eastern hellbender (Cryptobranchus alleganiensis alleganiensis is a large, fully aquatic paedamorphic salamander. Many populations are experiencing declines throughout their geographic range, yet the genetic ramifications of these declines are currently unknown. To this end, we examined levels of genetic variation and genetic structure at both range-wide and drainage (hierarchical scales. We collected 1,203 individuals from 77 rivers throughout nine states from June 2007 to August 2011. Levels of genetic diversity were relatively high among all sampling locations. We detected significant genetic structure across populations (Fst values ranged from 0.001 between rivers within a single watershed to 0.218 between states. We identified two genetically differentiated groups at the range-wide scale: 1 the Ohio River drainage and 2 the Tennessee River drainage. An analysis of molecular variance (AMOVA based on landscape-scale sampling of basins within the Tennessee River drainage revealed the majority of genetic variation (∼94-98% occurs within rivers. Eastern hellbenders show a strong pattern of isolation by stream distance (IBSD at the drainage level. Understanding levels of genetic variation and differentiation at multiple spatial and biological scales will enable natural resource managers to make more informed decisions and plan effective conservation strategies for cryptic, lotic species.

  19. The Massive Star Population in M101. II. Spatial Variations in the Recent Star Formation History

    CERN Document Server

    Grammer, Skyler

    2014-01-01

    We investigate the star formation history (SFH) as a function of radius in M101 using archival HST/ACS photometry. We derive the SFH from the resolved stellar populations in five 2' wide annuli. Binning the SFH into time frames corresponding to stellar populations traced by H$\\alpha$, far ultraviolet (FUV), and near ultraviolet (NUV) emission, we find that the fraction of stellar populations young enough to contribute in H$\\alpha$ is 15%-35% in the inner regions, compared to less than 5% in the outer regions. This provides a sufficient explanation for the lack of H$\\alpha$ emission at large radii. We also model the blue to red supergiant ratio in our five annuli, examine the effects that a metallicity gradient and variable SFH have on the predicted ratios, and compare to the observed values. We find that the radial behavior of our modeled blue to red supergiant ratios is highly sensitive to both spatial variations in the SFH and metallicity. Incorporating the derived SFH into modeled ratios, we find that we a...

  20. Lack of Spatial Immunogenetic Structure among Wolverine (Gulo gulo Populations Suggestive of Broad Scale Balancing Selection.

    Directory of Open Access Journals (Sweden)

    Yessica Rico

    Full Text Available Elucidating the adaptive genetic potential of wildlife populations to environmental selective pressures is fundamental for species conservation. Genes of the major histocompatibility complex (MHC are highly polymorphic, and play a key role in the adaptive immune response against pathogens. MHC polymorphism has been linked to balancing selection or heterogeneous selection promoting local adaptation. However, spatial patterns of MHC polymorphism are also influenced by gene flow and drift. Wolverines are highly vagile, inhabiting varied ecoregions that include boreal forest, taiga, tundra, and high alpine ecosystems. Here, we investigated the immunogenetic variation of wolverines in Canada as a surrogate for identifying local adaptation by contrasting the genetic structure at MHC relative to the structure at 11 neutral microsatellites to account for gene flow and drift. Evidence of historical positive selection was detected at MHC using maximum likelihood codon-based methods. Bayesian and multivariate cluster analyses revealed weaker population genetic differentiation at MHC relative to the increasing microsatellite genetic structure towards the eastern wolverine distribution. Mantel correlations of MHC against geographical distances showed no pattern of isolation by distance (IBD: r = -0.03, p = 0.9, whereas for microsatellites we found a relatively strong and significant IBD (r = 0.54, p = 0.01. Moreover, we found a significant correlation between microsatellite allelic richness and the mean number of MHC alleles, but we did not observe low MHC diversity in small populations. Overall these results suggest that MHC polymorphism has been influenced primarily by balancing selection and to a lesser extent by neutral processes such as genetic drift, with no clear evidence for local adaptation. This study contributes to our understanding of how vulnerable populations of wolverines may respond to selective pressures across their range.

  1. Development of a spatial stochastic multimedia exposure model to assess population exposure at a regional scale.

    Science.gov (United States)

    Caudeville, Julien; Bonnard, Roseline; Boudet, Céline; Denys, Sébastien; Govaert, Gérard; Cicolella, André

    2012-08-15

    Analyzing the relationship between the environment and health has become a major focus of public health efforts in France, as evidenced by the national action plans for health and the environment. These plans have identified the following two priorities: - identify and manage geographic areas where hotspot exposures are a potential risk to human health; and - reduce exposure inequalities. The aim of this study is to develop a spatial stochastic multimedia exposure model for detecting vulnerable populations and analyzing exposure determinants at a fine resolution and regional scale. A multimedia exposure model was developed by INERIS to assess the transfer of substances from the environment to humans through inhalation and ingestion pathways. The RESPIR project adds a spatial dimension by linking GIS (Geographic Information System) to the model. Tools are developed using modeling, spatial analysis and geostatistic methods to build and discretize interesting variables and indicators from different supports and resolutions on a 1-km(2) regular grid. We applied this model to the risk assessment of exposure to metals (cadmium, lead and nickel) using data from a region in France (Nord-Pas-de-Calais). The considered exposure pathways include the atmospheric contaminant inhalation and ingestion of soil, vegetation, meat, egg, milk, fish and drinking water. Exposure scenarios are defined for different reference groups (age, dietary properties, and the fraction of food produced locally). The two largest risks correspond to an ancient industrial site (Metaleurop) and the Lille agglomeration. In these areas, cadmium, vegetation ingestion and soil contamination are the principal determinants of the computed risk. PMID:22750175

  2. Spatial and seasonal trends of a natural population of Biomphalaria occidentalis in northeastern Argentina

    Directory of Open Access Journals (Sweden)

    Alejandra Rumi

    1992-06-01

    Full Text Available This study aims to analyze the age of a population of Biomphalaria occidentalis on a pound of Riachuelo river basin, wich is one of the three most important Middle Paraná river affluents in Corrientes province. Samples were drawn from three stations, were spatial and temporal numerical variations of the snail, as well as its relation with different environmental parameters, mainly temperature, rainfall, pH and conductivity, were analyzed. Snail abundance is given in number of individuals/hour. The differences between the three sampling stations, estimated by nonparametric tests, was nonsignificant. A relative scale to the greatest shell diameter was employed to build the age pyramids. Temporal fluctuations of snail abundance correlated negatively with the highest monthly accumulated temperatures (P < 0.05. Although different floristic compositions were observed at the three stations, no significant numerical variations were detected in B. occidentalis spatial distribution. Reproductive activity took place between March-April and November with overlapping cohort system. During summer (December-Febuary mortality increased along with temperature and reproductive activity was not evident.

  3. [Optimization model of spatial population structure: example of poplar moth laying eggs on leaves].

    Science.gov (United States)

    Sekretenko, O P; Sukhovol'skiĭ, V G; Tarasova, O V

    2002-01-01

    The authors analyze spatial distribution and survival of populations of poplar moth Litchcolletis populifoliella Tr. on its feeding plant--balsam poplar Populus balsamifera. Imago of the moth glue its eggs on the leaves thus determining the future location of their offspring on the host plant. Spatial distribution of eggs on leaf surface and distribution of leaves according egg numbers are not random. On the short distance from each egg the average number of eggs is less, than it should be in case of random distribution. While this distance increases up to some particular value the occurrence of eggs is higher than random. Thus, the eggs of moth are located by groups on the leaf surface. Within each group eggs are situated not very close to each other, this allowing larvae to lower competition for common resource. It is suggested that on the same feeding plant individuals have different interactions: competition, caused by limited quantity of resource and cooperation that is necessary to resist leaf defensive (antibiosis) reaction. PMID:12298182

  4. Spatial variation in water loss predicts terrestrial salamander distribution and population dynamics.

    Science.gov (United States)

    Peterman, W E; Semlitsch, R D

    2014-10-01

    Many patterns observed in ecology, such as species richness, life history variation, habitat use, and distribution, have physiological underpinnings. For many ectothermic organisms, temperature relationships shape these patterns, but for terrestrial amphibians, water balance may supersede temperature as the most critical physiologically limiting factor. Many amphibian species have little resistance to water loss, which restricts them to moist microhabitats, and may significantly affect foraging, dispersal, and courtship. Using plaster models as surrogates for terrestrial plethodontid salamanders (Plethodon albagula), we measured water loss under ecologically relevant field conditions to estimate the duration of surface activity time across the landscape. Surface activity time was significantly affected by topography, solar exposure, canopy cover, maximum air temperature, and time since rain. Spatially, surface activity times were highest in ravine habitats and lowest on ridges. Surface activity time was a significant predictor of salamander abundance, as well as a predictor of successful recruitment; the probability of a juvenile salamander occupying an area with high surface activity time was two times greater than an area with limited predicted surface activity. Our results suggest that survival, recruitment, or both are demographic processes that are affected by water loss and the ability of salamanders to be surface-active. Results from our study extend our understanding of plethodontid salamander ecology, emphasize the limitations imposed by their unique physiology, and highlight the importance of water loss to spatial population dynamics. These findings are timely for understanding the effects that fluctuating temperature and moisture conditions predicted for future climates will have on plethodontid salamanders. PMID:25154754

  5. Spatial and temporal evolution of Lassa virus in the natural host population in Upper Guinea.

    Science.gov (United States)

    Fichet-Calvet, Elisabeth; Ölschläger, Stephan; Strecker, Thomas; Koivogui, Lamine; Becker-Ziaja, Beate; Camara, Amara Bongo; Soropogui, Barré; Magassouba, N'Faly; Günther, Stephan

    2016-01-01

    This study aimed at reconstructing the spatial and temporal evolution of Lassa virus (LASV) in the natural host population. To this end, we generated 132 partial nucleoprotein sequences of LASV from M. natalensis trapped in 12 villages around Faranah, Upper Guinea, over a period of 12 years. This study reveals two main features of LASV evolution in M. natalensis. First, the virus evolves in the reservoir with a molecular clock rate of 9 (7-11) × 10(-4) position(-1) year(-1) implying that contemporary LASV lineages circulate in the Faranah area since less than 100 years. Second, viruses circulating in a specific village are diverse and polyphyletic. We observed, however, there are monophyletic clusters at village and sub-village level at specific points in time. In conclusion, our data indicate that the temporal and spatial pattern of LASV evolution in the natural reservoir is characterized by a combination of stationary circulation within a village and virus movement between villages. The latter feature is relevant for rodent control strategies, as it implies that recurrence of the virus from neighbouring villages may occur in villages where the virus has previously been eradicated. PMID:26911443

  6. Sexual selection drives speciation in an Amazonian frog

    Science.gov (United States)

    Boul, K.E.; Funk, W.C.; Darst, C.R.; Cannatella, D.C.; Ryan, M.J.

    2007-01-01

    One proposed mechanism of speciation is divergent sexual selection, whereby divergence in female preferences and male signals results in behavioural isolation. Despite the appeal of this hypothesis, evidence for it remains inconclusive. Here, we present several lines of evidence that sexual selection is driving behavioural isolation and speciation among populations of an Amazonian frog (Physalaemus petersi). First, sexual selection has promoted divergence in male mating calls and female preferences for calls between neighbouring populations, resulting in strong behavioural isolation. Second, phylogenetic analysis indicates that populations have become fixed for alternative call types several times throughout the species' range, and coalescent analysis rejects genetic drift as a cause for this pattern, suggesting that this divergence is due to selection. Finally, gene flow estimated with microsatellite loci is an average of 30 times lower between populations with different call types than between populations separated by a similar geographical distance with the same call type, demonstrating genetic divergence and incipient speciation. Taken together, these data provide strong evidence that sexual selection is driving behavioural isolation and speciation, supporting sexual selection as a cause for speciation in the wild. ?? 2006 The Royal Society.

  7. Sleep in an Amazonian manatee, Trichechus inunguis.

    Science.gov (United States)

    Mukhametov, L M; Lyamin, O I; Chetyrbok, I S; Vassilyev, A A; Diaz, R P

    1992-04-15

    For the first time, sleep was studied in a representative of the order of Sirenia. Slow wave sleep occupied 27%, and paradoxical sleep 1% of the total recording time in the Amazonian manatee. Trichechus inunguis. The circadian rhythmicity of sleep was pronounced. During the sleep period, the manatee woke up for a short time for each respiratory act. Interhemispheric asynchrony of the electrocortical slow wave activity was found. PMID:1582500

  8. Development of a spatial stochastic multimedia exposure model to assess population exposure at a regional scale

    Energy Technology Data Exchange (ETDEWEB)

    Caudeville, Julien, E-mail: Julien.CAUDEVILLE@ineris.fr [INERIS (French National Institute for Industrial Environment and Risks), Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France); Joint research unit UMR 6599, Heudiasyc (Heuristic and Diagnoses of Complex Systems), University of Technology of Compiegne and CNRS, Rue du Dr Schweitzer, 60200 Compiegne (France); Bonnard, Roseline, E-mail: Roseline.BONNARD@ineris.fr [INERIS (French National Institute for Industrial Environment and Risks), Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France); Boudet, Celine, E-mail: Celine.BOUDET@ineris.fr [INERIS (French National Institute for Industrial Environment and Risks), Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France); Denys, Sebastien, E-mail: Sebastien.DENYS@ineris.fr [INERIS (French National Institute for Industrial Environment and Risks), Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France); Govaert, Gerard, E-mail: gerard.govaert@utc.fr [Joint research unit UMR 6599, Heudiasyc (Heuristic and Diagnoses of Complex Systems), University of Technology of Compiegne and CNRS, Rue du Dr Schweitzer, 60200 Compiegne (France); Cicolella, Andre, E-mail: Andre.CICOLELLA@ineris.fr [INERIS (French National Institute for Industrial Environment and Risks), Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France)

    2012-08-15

    Analyzing the relationship between the environment and health has become a major focus of public health efforts in France, as evidenced by the national action plans for health and the environment. These plans have identified the following two priorities: -identify and manage geographic areas where hotspot exposures are a potential risk to human health; and -reduce exposure inequalities. The aim of this study is to develop a spatial stochastic multimedia exposure model for detecting vulnerable populations and analyzing exposure determinants at a fine resolution and regional scale. A multimedia exposure model was developed by INERIS to assess the transfer of substances from the environment to humans through inhalation and ingestion pathways. The RESPIR project adds a spatial dimension by linking GIS (Geographic Information System) to the model. Tools are developed using modeling, spatial analysis and geostatistic methods to build and discretize interesting variables and indicators from different supports and resolutions on a 1-km{sup 2} regular grid. We applied this model to the risk assessment of exposure to metals (cadmium, lead and nickel) using data from a region in France (Nord-Pas-de-Calais). The considered exposure pathways include the atmospheric contaminant inhalation and ingestion of soil, vegetation, meat, egg, milk, fish and drinking water. Exposure scenarios are defined for different reference groups (age, dietary properties, and the fraction of food produced locally). The two largest risks correspond to an ancient industrial site (Metaleurop) and the Lille agglomeration. In these areas, cadmium, vegetation ingestion and soil contamination are the principal determinants of the computed risk. -- Highlights: Black-Right-Pointing-Pointer We present a multimedia exposure model for mapping environmental disparities. Black-Right-Pointing-Pointer We perform a risk assessment on a region of France at a fine scale for three metals. Black-Right-Pointing-Pointer We

  9. Litter mercury deposition in the Amazonian rainforest.

    Science.gov (United States)

    Fostier, Anne Hélène; Melendez-Perez, José Javier; Richter, Larissa

    2015-11-01

    The objective of this work was to assess the flux of atmospheric mercury transferred to the soil of the Amazonian rainforest by litterfall. Calculations were based on a large survey of published and unpublished data on litterfall and Hg concentrations in litterfall samples from the Amazonian region. Litterfall based on 65 sites located in the Amazon rainforest averaged 8.15 ± 2.25 Mg ha(-1) y(-1). Average Hg concentrations were calculated from nine datasets for fresh tree leaves and ten datasets for litter, and a median concentration of 60.5 ng Hg g(-1) was considered for Hg deposition in litterfall, which averaged 49 ± 14 μg m(-2) yr(-1). This value was used to estimate that in the Amazonian rainforest, litterfall would be responsible for the annual removing of 268 ± 77 Mg of Hg, approximately 8% of the total atmospheric Hg deposition to land. The impact of the Amazon deforestation on the Hg biogeochemical cycle is also discussed. PMID:26312742

  10. Merger traces in the spatial distribution of stellar populations in the Fornax dSph galaxy

    CERN Document Server

    del Pino, Andrés; Hidalgo, Sebastial L

    2015-01-01

    We present a comprehensive and detailed study of the stellar populations of the Fornax dwarf spheroidal galaxy. We analyse their spatial distributions along the main body of the galaxy, obtaining their surface density maps, together with their radial density profiles. Results are based on the largest and most complete catalogue of stars in Fornax, with more than $3.5\\times10^{5}$ stars covering the main body of the galaxy up to $\\rm V \\sim 24$. We find a differentiated structure in Fornax depending on the stellar ages. Old stars ($\\gtrsim 10$ Gyr) follow an elliptical distribution well fitted by King profiles with relatively large core radius ($r_c = 760\\pm60$ pc). On another hand, young populations ($\\lesssim 3$ Gyr) concentrate in the central region of the galaxy ($r_c = 210\\pm10$ pc), and are better fitted by Sersic profiles with $0.8 < n < 1.2$, indicating some disky shape. These stars show strong asymmetries and substructures not aligned with the main optical axes of Fornax. This together with the ...

  11. Estimating temporal trend in the presence of spatial complexity: a Bayesian hierarchical model for a wetland plant population undergoing restoration.

    Science.gov (United States)

    Rodhouse, Thomas J; Irvine, Kathryn M; Vierling, Kerri T; Vierling, Lee A

    2011-01-01

    Monitoring programs that evaluate restoration and inform adaptive management are important for addressing environmental degradation. These efforts may be well served by spatially explicit hierarchical approaches to modeling because of unavoidable spatial structure inherited from past land use patterns and other factors. We developed bayesian hierarchical models to estimate trends from annual density counts observed in a spatially structured wetland forb (Camassia quamash [camas]) population following the cessation of grazing and mowing on the study area, and in a separate reference population of camas. The restoration site was bisected by roads and drainage ditches, resulting in distinct subpopulations ("zones") with different land use histories. We modeled this spatial structure by fitting zone-specific intercepts and slopes. We allowed spatial covariance parameters in the model to vary by zone, as in stratified kriging, accommodating anisotropy and improving computation and biological interpretation. Trend estimates provided evidence of a positive effect of passive restoration, and the strength of evidence was influenced by the amount of spatial structure in the model. Allowing trends to vary among zones and accounting for topographic heterogeneity increased precision of trend estimates. Accounting for spatial autocorrelation shifted parameter coefficients in ways that varied among zones depending on strength of statistical shrinkage, autocorrelation and topographic heterogeneity--a phenomenon not widely described. Spatially explicit estimates of trend from hierarchical models will generally be more useful to land managers than pooled regional estimates and provide more realistic assessments of uncertainty. The ability to grapple with historical contingency is an appealing benefit of this approach. PMID:22163047

  12. Estimating temporal trend in the presence of spatial complexity: A Bayesian hierarchical model for a wetland plant population undergoing restoration

    Science.gov (United States)

    Rodhouse, T.J.; Irvine, K.M.; Vierling, K.T.; Vierling, L.A.

    2011-01-01

    Monitoring programs that evaluate restoration and inform adaptive management are important for addressing environmental degradation. These efforts may be well served by spatially explicit hierarchical approaches to modeling because of unavoidable spatial structure inherited from past land use patterns and other factors. We developed Bayesian hierarchical models to estimate trends from annual density counts observed in a spatially structured wetland forb (Camassia quamash [camas]) population following the cessation of grazing and mowing on the study area, and in a separate reference population of camas. The restoration site was bisected by roads and drainage ditches, resulting in distinct subpopulations ("zones") with different land use histories. We modeled this spatial structure by fitting zone-specific intercepts and slopes. We allowed spatial covariance parameters in the model to vary by zone, as in stratified kriging, accommodating anisotropy and improving computation and biological interpretation. Trend estimates provided evidence of a positive effect of passive restoration, and the strength of evidence was influenced by the amount of spatial structure in the model. Allowing trends to vary among zones and accounting for topographic heterogeneity increased precision of trend estimates. Accounting for spatial autocorrelation shifted parameter coefficients in ways that varied among zones depending on strength of statistical shrinkage, autocorrelation and topographic heterogeneity-a phenomenon not widely described. Spatially explicit estimates of trend from hierarchical models will generally be more useful to land managers than pooled regional estimates and provide more realistic assessments of uncertainty. The ability to grapple with historical contingency is an appealing benefit of this approach.

  13. Extremely long-distance seed dispersal by an overfished Amazonian frugivore.

    Science.gov (United States)

    Anderson, Jill T; Nuttle, Tim; Saldaña Rojas, Joe S; Pendergast, Thomas H; Flecker, Alexander S

    2011-11-22

    Throughout Amazonia, overfishing has decimated populations of fruit-eating fishes, especially the large-bodied characid, Colossoma macropomum. During lengthy annual floods, frugivorous fishes enter vast Amazonian floodplains, consume massive quantities of fallen fruits and egest viable seeds. Many tree and liana species are clearly specialized for icthyochory, and seed dispersal by fish may be crucial for the maintenance of Amazonian wetland forests. Unlike frugivorous mammals and birds, little is known about seed dispersal effectiveness of fishes. Extensive mobility of frugivorous fish could result in extremely effective, multi-directional, long-distance seed dispersal. Over three annual flood seasons, we tracked fine-scale movement patterns and habitat use of wild Colossoma, and seed retention in the digestive tracts of captive individuals. Our mechanistic model predicts that Colossoma disperses seeds extremely long distances to favourable habitats. Modelled mean dispersal distances of 337-552 m and maximum of 5495 m are among the longest ever reported. At least 5 per cent of seeds are predicted to disperse 1700-2110 m, farther than dispersal by almost all other frugivores reported in the literature. Additionally, seed dispersal distances increased with fish size, but overfishing has biased Colossoma populations to smaller individuals. Thus, overexploitation probably disrupts an ancient coevolutionary relationship between Colossoma and Amazonian plants. PMID:21429923

  14. Voices of Contact: Politics of Language in Urban Amazonian Ecuador

    Science.gov (United States)

    Wroblewski, Michael

    2010-01-01

    This dissertation is a study of diverse linguistic resources and contentious identity politics among indigenous Amazonian Kichwas in the city of Tena, Ecuador. Tena is a rapidly developing Amazonian provincial capital city with a long history of interethnic and interlinguistic contact. In recent decades, the course of indigenous Kichwa identity…

  15. Spatial distribution pattern and dynamics of the primary population in a natural Populus euphratica forest in Tarim Basin, Xinjiang, China

    Institute of Scientific and Technical Information of China (English)

    Lu HAN; Haizhen WANG; Zhengli ZHOU; Zhijun LI

    2008-01-01

    One 50 m × 50 m standard plot was sampled in a natural forest of Populus euphratica in Awati County, situated at the edge of the Tarim Basin, Xinjiang Uygur Autonomous Region, China. The field investigation was conducted with a contiguous grid quadrate method. By means of a test of variance/mean value ratio, aggregation intensity index and theoretical distribution models, the spatial distribution pattern and the dynamics of primary populations in P. euphratica forest were studied. The results showed that the spatial distribution pattern of two dominant arbor populations conformed to clumped distribution. The aggregation intensity of the P. euphra-tica population was higher than that of P. pruinosa popu- lation. The spatial distribution pattern of two companion plant populations in the shrub layer also conformed to clump type, though the aggregation intensity of Tamarix chinensis was higher. In the herb layer, the distribution patterns of Glycyrrhiza uralensis and Asparagus persicus conformed respectively to a clumped pattern and a ran-dom pattern. The results of a Taylor power method test and Iwao's m2-x regression model also verified that both P. euphratica and P. pruinosa populations belong to a clumped pattern. Although the distribution pattern of P. pruinosa population at different development stages all belonged to a clumped distribution pattern, the aggrega-tion intensity dropped gradually along with age develop-ment. The distribution patterns of the P. euphratica population at different development stages changed from random type to clumped type, and further to random type. The differences in spatial distribution patterns of different populations at different development stages were related not only to ecological and biological characteris-tics of each species in the communities in the light of competitive exclusion principle among the populations, but were also closely related to the habitats in which the species lived in.

  16. An empirical study on the spatial distribution of the population, economy and water resources in Northeast China

    Science.gov (United States)

    Zhang, Conglin; Liu, Yu; Qiao, Haijuan

    The relationship among the population, economy and water resources is complex, and the contradictions and conflicts will appear and aggravate with the rapid development of economy and society in Northeast China. Based on the statistical analysis of the available data, this paper depicted the static distribution characteristics of the population, economy and water resources of Northeast China in 2011. It was found that the spatial distribution of the population, economy and water resources was unbalanced in Northeast China. The water resources mismatched with the population and economy. The population and economy were relatively dense and developed in the southwestern part of Northeast China respectively, while the water resources was relatively scarce. However, the situations in the northern part of Northeast China were opposite to those in the southwestern part. The population-economy inconsistence indexes of the cities in northern part of Northeast China showed a significant trend of spatial aggregation and heterogeneity. The cities with lower (1) inconsistence indexes all faced the problem of water resources shortage. Applying geometric gravity center method and grey correlation model, the result indicated that there was relatively high spatial relevance and the relative deviation among the spatial dynamic distributions of the population, economy and water resources was large. The gravity centers of economy and per capita average annual total water resources moved westward, while the gravity center of population gravity center moved eastward in the period of 1997-2011 in Northeast China. It must be noted that, the migration trend of the economy gravity center was more significant than those of the population and water resources.

  17. Spatial behaviour of little owls (Athene noctua) in a decreasing farmland population in Denmark

    DEFF Research Database (Denmark)

    Sunde, P.; Thorup, K.; Jacobsen, L. B.;

    We describe basic spatial behaviour and social organisation in the small and declining Danish population of little owls. The behaviour was mainly studied using radio tracking during 2005-2007 of 14 pairs of little owls, representing a total of 29 individuals.......We describe basic spatial behaviour and social organisation in the small and declining Danish population of little owls. The behaviour was mainly studied using radio tracking during 2005-2007 of 14 pairs of little owls, representing a total of 29 individuals....

  18. Spatial genetic analyses reveal cryptic population structure and migration patterns in a continuously harvested grey wolf (Canis lupus population in north-eastern Europe.

    Directory of Open Access Journals (Sweden)

    Maris Hindrikson

    Full Text Available Spatial genetics is a relatively new field in wildlife and conservation biology that is becoming an essential tool for unravelling the complexities of animal population processes, and for designing effective strategies for conservation and management. Conceptual and methodological developments in this field are therefore critical. Here we present two novel methodological approaches that further the analytical possibilities of STRUCTURE and DResD. Using these approaches we analyse structure and migrations in a grey wolf (Canislupus population in north-eastern Europe. We genotyped 16 microsatellite loci in 166 individuals sampled from the wolf population in Estonia and Latvia that has been under strong and continuous hunting pressure for decades. Our analysis demonstrated that this relatively small wolf population is represented by four genetic groups. We also used a novel methodological approach that uses linear interpolation to statistically test the spatial separation of genetic groups. The new method, which is capable of using program STRUCTURE output, can be applied widely in population genetics to reveal both core areas and areas of low significance for genetic groups. We also used a recently developed spatially explicit individual-based method DResD, and applied it for the first time to microsatellite data, revealing a migration corridor and barriers, and several contact zones.

  19. The spatial scale of genetic subdivision in populations of Ifremeria nautilei, a hydrothermal-vent gastropod from the southwest Pacific

    Directory of Open Access Journals (Sweden)

    Thaler Andrew D

    2011-12-01

    Full Text Available Abstract Background Deep-sea hydrothermal vents provide patchy, ephemeral habitats for specialized communities of animals that depend on chemoautotrophic primary production. Unlike eastern Pacific hydrothermal vents, where population structure has been studied at large (thousands of kilometres and small (hundreds of meters spatial scales, population structure of western Pacific vents has received limited attention. This study addresses the scale at which genetic differentiation occurs among populations of a western Pacific vent-restricted gastropod, Ifremeria nautilei. Results We used mitochondrial and DNA microsatellite markers to infer patterns of gene flow and population subdivision. A nested sampling strategy was employed to compare genetic diversity in discrete patches of Ifremeria nautilei separated by a few meters within a single vent field to distances as great as several thousand kilometres between back-arc basins that encompass the known range of the species. No genetic subdivisions were detected among patches, mounds, or sites within Manus Basin. Although I. nautilei from Lau and North Fiji Basins (~1000 km apart also exhibited no evidence for genetic subdivision, these populations were genetically distinct from the Manus Basin population. Conclusions An unknown process that restricts contemporary gene flow isolates the Manus Basin population of Ifremeria nautilei from widespread populations that occupy the North Fiji and Lau Basins. A robust understanding of the genetic structure of hydrothermal vent populations at multiple spatial scales defines natural conservation units and can help minimize loss of genetic diversity in situations where human activities are proposed and managed.

  20. Causes and Effects of Small-Scale Spatial Structure in Plant Populations

    OpenAIRE

    Law, R; Purves, D. W.; Murrell, D. J.; Dieckmann, U.

    2002-01-01

    Small-scale spatial structure is important in plant ecology. Plants interact primarily with their immediate neighbors and the view of the community as seen by an individual plant can be quite different from large-scale spatial average. We describe a spatial statistic that captures the plant's-eye view and use it to illustrate the strong spatial structure present in a grassland community. Many processes affect small-scale spatial structure, including intraspecific competition, dispersal of pro...

  1. Competition, mortality, and development of spatial patterns in two Cantabrian populations of Fagus sylvatica L. (Fagaceae

    Directory of Open Access Journals (Sweden)

    Fernández Prieto, José Antonio

    2000-06-01

    Full Text Available In this paper the spatial patterns of size and mortality of European beech (Fagus sylvatica L. were analy sed in two deciduous forest plots of Northern Spain. ¿i general terms, radial growth of F. sylvatica yields a direct relationship with size and an inverse relation with intraspecific competition while tree mortality seems be related to intraspecific competition. In the overall even-aged population, a lack of a recognisable structure in tree-size distribution, a small-scale regularity of survivors, and a regular pattern of dominant trees was noticed. This is a consequence of intense intraspecific competition at local level. In the old-growth plot, the wide repulsión between small and large beeches yields a specific spatial structure in tree-size distribution, showing even-sized groups of trees in different stages. Mortality in this plot occurs mainly within the dense group of small trees, which produces a broad regular pattern among the live beech trees. The random spatial pattern of dominant beeches seems to be characteristic of old-growth forests and could be a consequence of either self-thinning processes or exogenous factors.En el presente trabajo se analizan las distribuciones espaciales de tamaño y mortalidad en poblaciones de haya (Fagus sylvatica L. incluidas en dos parcelas de bosque atlántico. En general, el crecimiento radial de F. sylvatica es directamente proporcional al tamaño e inversamente proporcional a la competencia intraespecífica, mientras que la mortalidad parece estar condicionada por competencia con individuos de la misma especie. La población formada sobre todo por árboles coetáneos presenta características espaciales indicativas de una intensa competencia intraespecífica entre árboles vecinos, como lo son la ausencia de una distribución ordenada de tamaños, regularidad local de los árboles vivos y un patrón regular en los árboles dominantes. La población incluida en bosque maduro presenta una

  2. Landscape variability explains spatial pattern of population structure of northern pike (Esox lucius) in a large fluvial system

    OpenAIRE

    Ouellet-Cauchon, Geneviève; Mingelbier, Marc; Lecomte, Frédéric; Bernatchez, Louis

    2014-01-01

    A growing number of studies have been investigating the influence of contemporary environmental factors on population genetic structure, but few have addressed the issue of spatial patterns in the variable intensity of factors influencing the extent of population structure, and particularly so in aquatic ecosystems. In this study, we document the landscape genetics of northern pike (Esox lucius), based on the analysis of nearly 3000 individuals from 40 sampling sites using 22 microsatellites ...

  3. Love thy neighbour or opposites attract? Patterns of spatial segregation and association among crested penguin populations during winter

    OpenAIRE

    Ratcliffe, Norman; Crofts, Sarah; Brown, Ruth; Baylis, Alastair M M; Adlard, Stacey; Horswill, Catharine; Venables, Hugh; Taylor, Phil; Philip N Trathan; Staniland, Iain J.

    2014-01-01

    Aim Competition for food among populations of closely related species and conspecifics that occur in both sympatry and parapatry can be reduced by interspecific and intraspecific spatial segregation. According to predictions of niche partitioning, segregation is expected to occur at habitat boundaries among congeners and within habitats among conspecifics, while negative relationships in the density of species or populations will occur in areas of overlap. We tested these predictions by model...

  4. Love thy neighbour or opposites attract? Patterns of spatial segregation and association among crested penguin populations during winter

    OpenAIRE

    Ratcliffe, Norman; Crofts, Sarah; Brown, Ruth; Baylis, Alistair M.M.; Adlard, Stacey; Horswill, Catharine; Venables, Hugh; Taylor, Phil; Philip N Trathan; Staniland, Iain J.

    2014-01-01

    Competition for food among populations of closely related species and conspecifics that occur in both sympatry and parapatry can be reduced by interspecific and intraspecific spatial segregation. According to predictions of niche partitioning, segregation is expected to occur at habitat boundaries among congeners and within habitats among conspecifics, while negative relationships in the density of species or populations will occur in areas of overlap. We tested these predictions by modelling...

  5. Health and demography of native Amazonians: historical perspective and current status Saúde e demografia de povos indígenas amazônicos: perspectiva histórica e situação atual

    OpenAIRE

    Warren M. Hern

    1991-01-01

    Native Amazonians have been the victims of two massive historical assaults, one at the time of the Conquest and the other during the Twentieth century. Due to epidemic disease and environmental destruction, many tribes have gone from contact to displacement, decimation, and extinction in a single generation. Deculturation and the construction of large development projects have had catastrophic effects on native populations. In many ways, native Amazonians have experienced a reverse of the "Ep...

  6. Sampling strategy for wild soybean (Glycine soja) populations based on their genetic diversity and fine-scale spatial genetic structure

    Institute of Scientific and Technical Information of China (English)

    ZHU Weiyue; ZHOU Taoying; ZHONG Ming; LU Baorong

    2007-01-01

    A total of 892 individuals sampled from a wild soybean population in a natural reserve near the Yellow River estuary located in Kenli of Shandong Province (China) were investigated.Seventeen SSR (simple sequence repeat) primer pairs from cultivated soybeans were used to estimate the genetic diversity of the population and its variation pattern versus changes of the sample size (sub-samples),in addition to investigating the fine-scale spatial genetic structure within the population.The results showed relatively high genetic diversity of the population with the mean value of allele number (A) being 2.88,expected heterozygosity (He) 0.431,Shannon diversity index (/) 0.699,and percentage of polymorphic loci (P) 100%.Sub-samples of different sizes (ten groups) were randomly drawn from the population and their genetic diversity was calculated by computer simulation.The regression model of the four diversity indexes with the change of sample sizes was computed.As a result,27-52 individuals can reach 95% of total genetic variability of the population.Spatial autocorrelation analysis revealed that the genetic patch size of this wild soybean population is about 18 m.The study provided a scientific basis for the sampling strategy of wild soybean populations.

  7. Spatial evolution of short pulses under conditions of coherent population trapping

    CERN Document Server

    Arkhipkin, V G

    2001-01-01

    We study the features of spatial and temporal evolution of two powerful short different-wavelength laser pulses interacting with optical dense three-level Lambda-type medium under condition of coherent population trapping for the general case of unequal transition oscillator strengths. The pulses are simultaneously sent into an atom. The durations of probe and coupling pulses $T_{1,2}$ ($T_2>T_1$) are supposed to be shorter than all relaxation times in the medium. We present analytical and numerical solutions of the self-consistent set of coupled Schr\\"{o}dinger equations and reduced wave equations in adiabatic limit with taking into account the first non-adiabatic correction. The adiabaticity criterion with account of pulse propagation is studied. We find that propagation dynamics depends on the relationship between the transition oscillator strengths. It is shown that at the initial stage of propagation the envelopes of the pulses slightly change along the length of the medium. This distance can be large co...

  8. Spatial genetic structure of Salvia japonica Thunb. population (Labiatae in Botanical Garden of Osaka City University, Kisaichi, Osaka Prefecture, Japan

    Directory of Open Access Journals (Sweden)

    SUDARMONO

    2005-10-01

    Full Text Available Salvia japonica Thunb. (Japan: Aki-no-Tamurasou was a perennial herb, protandry insect-pollinated, and self-incompatible with water-flow dispersed seed. We used allozyme loci to know genetic structure of a S. japonica population. We examined spatial autocorrelation of individuals within five distance class with Moran`s I statistics. The area of observation was in plot 5x5 m2 in Botanical Garden of Osaka City University, Kisaichi, Katano, Osaka Prefecture. The 8 loci examined were polymorphic, namely Aat-1, Aat-2, Pgi, Mnr, Pgm-1, Pgm-2, Idh, and 6-Pgd. Low levels of genetic diversity were found for 29 individuals. Ninety-two percent cases for all of distance class were similar and only 8% (8 of 105 cases were significant differences. This result indicated that the spatial genetic distributions in all of distance classes were all similar and no spatial autocorrelation of genotypes. Only in distance class 2 had one significantly positive cases (0.15 in Pgm-1c, indicating that spatial genetic structure in the study population was weak at most. In the other word that spatial pattern of the individuals within S. japonica population was random. Overall of the result was indicating that genotype among individuals of S. japonica changed distantly and tended to isolation in distance by seed dispersed.

  9. Complex Spatial Structure in a Population of Didymopanax pittieri, A Tree of Wind-Exposed Lower Montane Rain Forest

    Science.gov (United States)

    Lawton, Robert M.; Lawton, Robert O.

    2010-01-01

    Didymopanax pittieri is a common shade-intolerant tree colonizing treefall gaps in the elfin forests on windswept ridgecrests in the lower montane rain forests of the Cordillera de Tilarain, Costa Rica. All D. pittieri taller than > 0.5 m in a 5.2-ha elfin forested portion of a gridded study watershed in the Monteverde Cloud Forest Preserve were located, mapped, and measured. This local population of D. pittieri is spatially inhomogeneous, in that density increases with increasing wind exposure; D. pittieri are more abundant near ridge crests than lower on windward slopes. The important and ubiquitous phenomenon of spatial inhomogeneity in population density is addressed and corrected for in spatial analyses by the application of the inhomogeneous version of Ripley's K. The spatial patterns of four size classes of D. pittieri (dbh, 5-10 cm dbh, 10-20 cm dbh, and> 20 cm dbh) were investigated. Within the large-scale trend in density driven by wind exposure, D. pittieri saplings are clumped at the scale of treefall gaps and at the scale of patches of aggregated gaps. D. pittieri 5-10 cm dbh are randomly distributed, apparently due to competitive thinning of sapling clumps during the early stages of gap-phase regeneration. D. pittieri larger than 10 cm dbh are overdispersed at a scale larger than that of patches of gaps. Natural disturbance can influence the distribution of shade intolerant tree populations at several different spatial scales, and can have discordant effects at different life history stages.

  10. Complex Spatial Structure in a Population of Didymopanax pittieri, A Tree of Wind-Exposed Lower Montane Rain Forest

    Science.gov (United States)

    Lawton, Robert M.; Lawton, Robert O.

    2010-01-01

    Didymopanax pittieri is a common shade-intolerant tree colonizing treefall gaps in the elfin forests on windswept ridgecrests in the lower montane rain forests of the Cordillera de Tilarain, Costa Rica. All D. pittieri taller than > 0.5 m in a 5.2-ha elfin forested portion of a gridded study watershed in the Monteverde Cloud Forest Preserve were located, mapped, and measured. This local population of D. pittieri is spatially inhomogeneous, in that density increases with increasing wind exposure; D. pittieri are more abundant near ridge crests than lower on windward slopes. The important and ubiquitous phenomenon of spatial inhomogeneity in population density is addressed and corrected for in spatial analyses by the application of the inhomogeneous version of Ripley's K. The spatial patterns of four size classes of D. pittieri ( 20 cm dbh) were investigated. Within the large-scale trend in density driven by wind exposure, D. pittieri saplings are clumped at the scale of treefall gaps and at the scale of patches of aggregated gaps. D. pittieri 5-10 cm dbh are randomly distributed, apparently due to competitive thinning of sapling clumps during the early stages of gap-phase regeneration. D. pittieri larger than 10 cm dbh are overdispersed at a scale larger than that of patches of gaps. Natural disturbance can influence the distribution of shade intolerant tree populations at several different spatial scales, and can have discordant effects at different life history stages.

  11. A size-structured simulation model for evaluating management strategies in gillnet fisheries exploiting spatially differentiated populations.

    NARCIS (Netherlands)

    Pet, J.S.; Machiels, M.A.M.; Densen, van W.L.T.

    1996-01-01

    A length-structured simulation model is presented as a tool in decision making for gillnet fisheries management. The analytical model simulates the fish population dynamics and impact of the fisheries, taking into account size-dependent spatial distribution patterns and migration of the fish. The da

  12. Regimes of spatial ordering in Brazil: neoliberalism, leftist populism and modernist aesthetics in slum upgrading in Recife

    NARCIS (Netherlands)

    Nuijten, M.C.M.; Koster, M.; Vries, de P.A.

    2012-01-01

    This paper shows how regimes of spatial ordering in Brazil are produced by the entangling of neoliberalism, leftist populism and modernist visions. The paper focuses on Prometrópole, a slum upgrading project in Recife funded by the World Bank, which commenced in 2007. In this project, the neoliberal

  13. Les connaissances au quotidien : perceptions et savoirs des populations riveraines de l’Amazonie sur leurs ressources halieutiques Conhecimentos no cotidiano : percepções e saberes de populações ribeirinhas da Amazônia sobre seus recursos haliêuticos  Knowledge in everyday life: perceptions and knowledges of riparian Amazonian populations on their fishery resources

    Directory of Open Access Journals (Sweden)

    S. Paquet

    2011-12-01

    nova luz sobre as questões relacionadas a gestão dos recursos hídricos e levantam lacunas impedindo uma real apropriação dos problemas ambientais e o surgimento de soluções locais. De fato, nós mostramos que o desmatamento e a erosão das margens do rio foram percebidos como as principais mudanças ambientais observadas ao longo do tempo. A diminuição na abundância e/ou a redução do tamanho dos peixes também foi relatada pelos entrevistados. A falta de conexão pelos pescadores entre as mudanças observadas nos ecossistemas naturais e as mudanças ocorridas nas populações de peixes chamou a nossa atenção. Por conseguinte, qualquer intervenção visando o desenvolvimento e/ou a implementação de métodos sustentáveis de exploração dos recursos haliêuticos deve passar por uma atividade preliminar de informação. A intenção sendo gerar a apropriação local das questões ambientais e de favorecer a emergência de soluções ao seio mesmo das comunidades em questão.In this paper we are interested on subsistence fishing practiced by riparian Amazonian populations. The results presented, concerning the traditional knowledge of inhabitants, their perceptions about the environmental changes and the evolution of fishery resources as well as the some solutions regarding these changes, derived from two surveys administated to twelve communities of the Tapajós Basin. These results shed new light on issues related to the management of fisheries resources and highlight the gaps preventing a real appropriation of environmental problems and the emergence of local solutions. Indeed, we show that deforestation and erosion of river banks were perceived as the major environmental changes observed over the time.The decrease in abundance and/or reduction in the sizes of fish was also been reported by respondents. The lack of connection between the observed changes in natural ecosystems and changes in fish stocks caught our attention. Consequently, any

  14. Estimating temporal trend in the presence of spatial complexity: a Bayesian hierarchical model for a wetland plant population undergoing restoration.

    Directory of Open Access Journals (Sweden)

    Thomas J Rodhouse

    Full Text Available Monitoring programs that evaluate restoration and inform adaptive management are important for addressing environmental degradation. These efforts may be well served by spatially explicit hierarchical approaches to modeling because of unavoidable spatial structure inherited from past land use patterns and other factors. We developed bayesian hierarchical models to estimate trends from annual density counts observed in a spatially structured wetland forb (Camassia quamash [camas] population following the cessation of grazing and mowing on the study area, and in a separate reference population of camas. The restoration site was bisected by roads and drainage ditches, resulting in distinct subpopulations ("zones" with different land use histories. We modeled this spatial structure by fitting zone-specific intercepts and slopes. We allowed spatial covariance parameters in the model to vary by zone, as in stratified kriging, accommodating anisotropy and improving computation and biological interpretation. Trend estimates provided evidence of a positive effect of passive restoration, and the strength of evidence was influenced by the amount of spatial structure in the model. Allowing trends to vary among zones and accounting for topographic heterogeneity increased precision of trend estimates. Accounting for spatial autocorrelation shifted parameter coefficients in ways that varied among zones depending on strength of statistical shrinkage, autocorrelation and topographic heterogeneity--a phenomenon not widely described. Spatially explicit estimates of trend from hierarchical models will generally be more useful to land managers than pooled regional estimates and provide more realistic assessments of uncertainty. The ability to grapple with historical contingency is an appealing benefit of this approach.

  15. Entrainment and Control of Bacterial Populations: An in Silico Study over a Spatially Extended Agent Based Model.

    Science.gov (United States)

    Mina, Petros; Tsaneva-Atanasova, Krasimira; Bernardo, Mario di

    2016-07-15

    We extend a spatially explicit agent based model (ABM) developed previously to investigate entrainment and control of the emergent behavior of a population of synchronized oscillating cells in a microfluidic chamber. Unlike most of the work in models of control of cellular systems which focus on temporal changes, we model individual cells with spatial dependencies which may contribute to certain behavioral responses. We use the model to investigate the response of both open loop and closed loop strategies, such as proportional control (P-control), proportional-integral control (PI-control) and proportional-integral-derivative control (PID-control), to heterogeinities and growth in the cell population, variations of the control parameters and spatial effects such as diffusion in the spatially explicit setting of a microfluidic chamber setup. We show that, as expected from the theory of phase locking in dynamical systems, open loop control can only entrain the cell population in a subset of forcing periods, with a wide variety of dynamical behaviors obtained outside these regions of entrainment. Closed-loop control is shown instead to guarantee entrainment in a much wider region of control parameter space although presenting limitations when the population size increases over a certain threshold. In silico tracking experiments are also performed to validate the ability of classical control approaches to achieve other reference behaviors such as a desired constant output or a linearly varying one. All simulations are carried out in BSim, an advanced agent-based simulator of microbial population which is here extended ad hoc to include the effects of control strategies acting onto the population. PMID:27110835

  16. Evaluation of a spatially resolved forest fire smoke model for population-based epidemiologic exposure assessment.

    Science.gov (United States)

    Yao, Jiayun; Eyamie, Jeff; Henderson, Sarah B

    2016-05-01

    Exposure to forest fire smoke (FFS) is associated with multiple adverse health effects, mostly respiratory. Findings for cardiovascular effects have been inconsistent, possibly related to the limitations of conventional methods to assess FFS exposure. In previous work, we developed an empirical model to estimate smoke-related fine particulate matter (PM2.5) for all populated areas in British Columbia (BC), Canada. Here, we evaluate the utility of our model by comparing epidemiologic associations between modeled and measured PM2.5. For each local health area (LHA), we used Poisson regression to estimate the effects of PM2.5 estimates and measurements on counts of medication dispensations and outpatient physician visits. We then used meta-regression to estimate the overall effects. A 10 μg/m(3) increase in modeled PM2.5 was associated with increased sabutamol dispensations (RR=1.04, 95% CI 1.03-1.06), and physician visits for asthma (1.06, 1.04-1.08), COPD (1.02, 1.00-1.03), lower respiratory infections (1.03, 1.00-1.05), and otitis media (1.05, 1.03-1.07), all comparable to measured PM2.5. Effects on cardiovascular outcomes were only significant using model estimates in all LHAs during extreme fire days. This suggests that the exposure model is a promising tool for increasing the power of epidemiologic studies to detect the health effects of FFS via improved spatial coverage and resolution. PMID:25294305

  17. Development of population geography from antropogeography to spatial-analitical approach

    OpenAIRE

    Spasovski Milena; Šantić Danica

    2013-01-01

    Population geography is a subdiscipline of Human geography and studies the distribution, concentration and density of population over the terestrial surface, as well as differences in population size, changes and characteristics, like structures, migrations, activity etc, among some places present compared to others. Population geography has had a perscientific stage as long as human history. First modern scientific treatis of population in geography was th...

  18. Evaluating effects of Everglades restoration on American crocodile populations in south Florida using a spatially-explicit, stage-based population model

    Science.gov (United States)

    Green, Timothy W.; Slone, Daniel H.; Swain, Eric D.; Cherkiss, Michael S.; Lohmann, Melinda; Mazzotti, Frank J.; Rice, Kenneth G.

    2014-01-01

    The distribution and abundance of the American crocodile (Crocodylus acutus) in the Florida Everglades is dependent on the timing, amount, and location of freshwater flow. One of the goals of the Comprehensive Everglades Restoration Plan (CERP) is to restore historic freshwater flows to American crocodile habitat throughout the Everglades. To predict the impacts on the crocodile population from planned restoration activities, we created a stage-based spatially explicit crocodile population model that incorporated regional hydrology models and American crocodile research and monitoring data. Growth and survival were influenced by salinity, water depth, and density-dependent interactions. A stage-structured spatial model was used with discrete spatial convolution to direct crocodiles toward attractive sources where conditions were favorable. The model predicted that CERP would have both positive and negative impacts on American crocodile growth, survival, and distribution. Overall, crocodile populations across south Florida were predicted to decrease approximately 3 % with the implementation of CERP compared to future conditions without restoration, but local increases up to 30 % occurred in the Joe Bay area near Taylor Slough, and local decreases up to 30 % occurred in the vicinity of Buttonwood Canal due to changes in salinity and freshwater flows.

  19. Hyperdominance in Amazonian forest carbon cycling

    Science.gov (United States)

    Fauset, Sophie; Johnson, Michelle O.; Gloor, Manuel; Baker, Timothy R.; Monteagudo M., Abel; Brienen, Roel J.W.; Feldpausch, Ted R.; Lopez-Gonzalez, Gabriela; Malhi, Yadvinder; ter Steege, Hans; Pitman, Nigel C.A.; Baraloto, Christopher; Engel, Julien; Pétronelli, Pascal; Andrade, Ana; Camargo, José Luís C.; Laurance, Susan G.W.; Laurance, William F.; Chave, Jerôme; Allie, Elodie; Vargas, Percy Núñez; Terborgh, John W.; Ruokolainen, Kalle; Silveira, Marcos; Aymard C., Gerardo A.; Arroyo, Luzmila; Bonal, Damien; Ramirez-Angulo, Hirma; Araujo-Murakami, Alejandro; Neill, David; Hérault, Bruno; Dourdain, Aurélie; Torres-Lezama, Armando; Marimon, Beatriz S.; Salomão, Rafael P.; Comiskey, James A.; Réjou-Méchain, Maxime; Toledo, Marisol; Licona, Juan Carlos; Alarcón, Alfredo; Prieto, Adriana; Rudas, Agustín; van der Meer, Peter J.; Killeen, Timothy J.; Marimon Junior, Ben-Hur; Poorter, Lourens; Boot, Rene G.A.; Stergios, Basil; Torre, Emilio Vilanova; Costa, Flávia R.C.; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Groot, Nikée; Arets, Eric; Moscoso, Victor Chama; Castro, Wendeson; Coronado, Euridice N. Honorio; Peña-Claros, Marielos; Stahl, Clement; Barroso, Jorcely; Talbot, Joey; Vieira, Ima Célia Guimarães; van der Heijden, Geertje; Thomas, Raquel; Vos, Vincent A.; Almeida, Everton C.; Davila, Esteban Álvarez; Aragão, Luiz E.O.C.; Erwin, Terry L.; Morandi, Paulo S.; de Oliveira, Edmar Almeida; Valadão, Marco B.X.; Zagt, Roderick J.; van der Hout, Peter; Loayza, Patricia Alvarez; Pipoly, John J.; Wang, Ophelia; Alexiades, Miguel; Cerón, Carlos E.; Huamantupa-Chuquimaco, Isau; Di Fiore, Anthony; Peacock, Julie; Camacho, Nadir C. Pallqui; Umetsu, Ricardo K.; de Camargo, Plínio Barbosa; Burnham, Robyn J.; Herrera, Rafael; Quesada, Carlos A.; Stropp, Juliana; Vieira, Simone A.; Steininger, Marc; Rodríguez, Carlos Reynel; Restrepo, Zorayda; Muelbert, Adriane Esquivel; Lewis, Simon L.; Pickavance, Georgia C.; Phillips, Oliver L.

    2015-01-01

    While Amazonian forests are extraordinarily diverse, the abundance of trees is skewed strongly towards relatively few ‘hyperdominant' species. In addition to their diversity, Amazonian trees are a key component of the global carbon cycle, assimilating and storing more carbon than any other ecosystem on Earth. Here we ask, using a unique data set of 530 forest plots, if the functions of storing and producing woody carbon are concentrated in a small number of tree species, whether the most abundant species also dominate carbon cycling, and whether dominant species are characterized by specific functional traits. We find that dominance of forest function is even more concentrated in a few species than is dominance of tree abundance, with only ≈1% of Amazon tree species responsible for 50% of carbon storage and productivity. Although those species that contribute most to biomass and productivity are often abundant, species maximum size is also influential, while the identity and ranking of dominant species varies by function and by region. PMID:25919449

  20. The Lewis Histo-Blood Group System: Molecular Analysis of the 59T>G, 508G>A, and 1067T>A Polymorphisms in an Amazonian Population

    OpenAIRE

    Corvelo, Tereza Cristina de Oliveira; de Loiola, Rosane do Socorro Pompeu; Aguiar, Délia Cristina Figueira; de Matos, Gyselly de Cássia Bastos; de Brito, Danielle Calado

    2013-01-01

    Background The Lewis (FUT3) gene is responsible for the expression of the Lea and Leb blood group antigens. The individuals, who not synthesize these antigens have the phenotype Lewis negative, due to the presence of some single nucleotide polymorphisms (SNPs), such as 59T>G, 508G>A and 1067T>A, whose distribution is different in various ethnic groups. Our aim was to verify the frequencies of these SNPs in an admixed population of Belém-Pará-Brazil. Materials and Methods Polymerase chain reac...

  1. Agricultura e alimentação em populações ribeirinhas das várzeas do Amazonas: novas perspectivas Agriculture and diet among riverine populations of the Amazonian floodplains: new perspectives

    Directory of Open Access Journals (Sweden)

    Cristina Adams

    2005-01-01

    Full Text Available Este trabalho tem como objetivo a caracterização e comparação dos consumos alimentares domésticos de duas comunidades caboclas localizadas numa região de várzea sazonal (Ilha do Ituqui, Santarém-PA no Baixo Amazonas (1995-97. Especial ênfase é dada ao papel da agricultura no consumo alimentar destas populações. Os resultados obtidos indicam níveis elevados de consumo protéico em relação ao calórico, pela população local, relativa instabilidade sazonal das fontes de energia e crescente dependência de itens alimentares industrializados. Apesar deste perfil, produtos localmente produzidos e obtidos, como a farinha de mandioca e o peixe, ainda representam grande parte da estrutura dietética destas populações. Somado a isto, um amplo leque de atividades de subsistência e de mercado, bem como a exploração de diferentes zonas ecológicas na obtenção de alimento, foram observados, desmistificando algumas das pressuposições dominantes até recentemente sobre a homogeneidade e simplicidade das estratégias produtivas destas populações.The main objective of this research is to characterize and compare household food intake of two riverine populations located in the Floodplains of the Lower Amazon (Ituqui Island, Santarém-PA (1995-97. A special emphasis is given to the role of agriculture in the food consumption patterns of these populations. The obtained results indicate high levels of protein intake in relation to energy intake, relative seasonal instability of energy sources, and increasing dependency on imported industrialized foodstuffs. In spite of such a pattern, food items locally produced such as manioc flour (farinha and fish remain as the main part of local diet. In addition, a broad array of subsistence and commercial activities as well as the intense exploitation of different ecological zones by the local population were observed. The above scenario tends to undermine some of the major assumptions on the

  2. The interaction between the spatial distribution of resource patches and population density: consequences for intraspecific growth and morphology.

    Science.gov (United States)

    Jacobson, Bailey; Grant, James W A; Peres-Neto, Pedro R

    2015-07-01

    How individuals within a population distribute themselves across resource patches of varying quality has been an important focus of ecological theory. The ideal free distribution predicts equal fitness amongst individuals in a 1 : 1 ratio with resources, whereas resource defence theory predicts different degrees of monopolization (fitness variance) as a function of temporal and spatial resource clumping and population density. One overlooked landscape characteristic is the spatial distribution of resource patches, altering the equitability of resource accessibility and thereby the effective number of competitors. While much work has investigated the influence of morphology on competitive ability for different resource types, less is known regarding the phenotypic characteristics conferring relative ability for a single resource type, particularly when exploitative competition predominates. Here we used young-of-the-year rainbow trout (Oncorhynchus mykiss) to test whether and how the spatial distribution of resource patches and population density interact to influence the level and variance of individual growth, as well as if functional morphology relates to competitive ability. Feeding trials were conducted within stream channels under three spatial distributions of nine resource patches (distributed, semi-clumped and clumped) at two density levels (9 and 27 individuals). Average trial growth was greater in high-density treatments with no effect of resource distribution. Within-trial growth variance had opposite patterns across resource distributions. Here, variance decreased at low-population, but increased at high-population densities as patches became increasingly clumped as the result of changes in the levels of interference vs. exploitative competition. Within-trial growth was related to both pre- and post-trial morphology where competitive individuals were those with traits associated with swimming capacity and efficiency: larger heads/bodies/caudal fins

  3. Mapping Amazonian Canopy Foliar Traits with Imaging Spectroscopy

    Science.gov (United States)

    Asner, G. P.; Martin, R.; Anderson, C. B.; Knapp, D. E.

    2014-12-01

    Spatial and temporal information on plant functional traits is lacking in ecology, which limits our understanding of how plant communities and ecosystems are changing. This problem is acute in remote tropical regions such as in Andean and Amazonian forests, where information on plant functional traits is difficult to ascertain. We used Carnegie Airborne Observatory visible-to-shortwave infrared (VSWIR) imaging spectroscopy with light detection and ranging (LiDAR) to assess the chemical composition of tropical forests along a 3000 m elevation gradient from lowland Amazonia to the Andean treeline. We calibrated and validated the retrieval of 15 canopy foliar chemicals and leaf mass per area (LMA) in 81 one-hectare field plots using a new VSWIR-LiDAR fusion approach. Remotely sensed estimates of elevational changes in forest foliar pigments, nitrogen, phosphorus, water, soluble and total carbon, cellulose and LMA were similar to those derived via laborious field survey and laboratory analysis. This new airborne approach addresses the inherent limitations and sampling biases associated with field-based studies of forest functional traits, particularly in structurally and floristically complex tropical canopies.

  4. Carbon Dioxide and Methane Evasion from Amazonian Rivers and Lakes

    Science.gov (United States)

    Melack, J. M.; Barbosa, P.; Schofield, V.; Amaral, J.; Forsberg, B.; Farjalla, V.

    2013-12-01

    Floodplains, with their mosaic of aquatic habitats, constitute the majority of the wetlands of South America. We report 1) estimates of CH4 and CO2 flux from Amazonian floodplain lakes and rivers during low, rising and high water periods, and 2) identify environmental factors regulating these fluxes. We sampled 10 floodplain lakes, 4 tributaries of Solimões River, 6 stations on the Solimões main stem and 1 station on the Madeira, Negro and Amazonas rivers. Diffusive fluxes were measured with static floating chambers. CH4 fluxes were highly variable, with the majority of the values lower than 5 mmol m-2 d-1. For the lakes, no significant differences among the periods were found. CH4 concentration in the water and water temperature were the two main environmental factors regulating the diffusive flux. Our results highlight the importance of considering both the spatial and temporal scales when estimating CH4 fluxes for a region. CO2 fluxes from water to atmosphere ranged between 327 and -21 mmol m-2 d-1, averaging 58 mmol m-2 d-1. We found higher evasion rates in lakes than in rivers. For both systems the lowest rates were found in low water. pH and dissolved oxygen, phosphorous and organic carbon were the main factors correlated to CO2 evasion from the water bodies.

  5. From Locational Fundamentals to Increasing Returns: The Spatial Concentration of Population in Spain, 1787-2000

    OpenAIRE

    María Isabel Ayuda; Fernando Collantes; Vicente Pinilla

    2005-01-01

    Does population follow the same inverted-U pattern of concentration/dispersion that has been found in the case of economic activity in the long run? In this paper we present the evidence for eight European countries during the nineteenth and twentieth centuries and find that, contrary to the inverted-U hypothesis, population has shown a steady, long-run trend towards concentration. After that, we estimate population density and population growth equations for the case of one of these countrie...

  6. Integrating landscape genomics and spatially explicit approaches to detect loci under selection in clinal populations

    OpenAIRE

    Jones, Matthew R.; Forester, Brenna R.; Teufel, Ashley I.; Adams, Rachael V.; Anstett, Daniel N.; Goodrich, Betsy A.; Erin L. Landguth; Joost, Stéphane; Manel, Stéphanie

    2013-01-01

    Uncovering the genetic basis of adaptation hinges on the ability to detect loci under selection. However, population genomics outlier approaches to detect selected loci may be inappropriate for clinal populations or those with unclear population structure because they require that individuals be clustered into populations. An alternate approach, landscape genomics, uses individual-based approaches to detect loci under selection and reveal potential environmental drivers of selection. We teste...

  7. Dynamics of carbon, biomass, and structure in two Amazonian forests

    Science.gov (United States)

    Pyle, Elizabeth Hammond; Santoni, Gregory W.; Nascimento, Henrique E. M.; Hutyra, Lucy R.; Vieira, Simone; Curran, Daniel J.; van Haren, Joost; Saleska, Scott R.; Chow, V. Y.; Carmago, Plinio B.; Laurance, William F.; Wofsy, Steven C.

    2008-11-01

    Amazon forests are potentially globally significant sources or sinks for atmospheric carbon dioxide. In this study, we characterize the spatial trends in carbon storage and fluxes in both live and dead biomass (necromass) in two Amazonian forests, the Biological Dynamic of Forest Fragments Project (BDFFP), near Manaus, Amazonas, and the Tapajós National Forest (TNF) near Santarém, Pará. We assessed coarse woody debris (CWD) stocks, tree growth, mortality, and recruitment in ground-based plots distributed across the terra firme forest at both sites. Carbon dynamics were similar within each site, but differed significantly between the sites. The BDFFP and the TNF held comparable live biomass (167 +/- 7.6 MgC.ha-1 versus 149 +/- 6.0 MgC.ha-1, respectively), but stocks of CWD were 2.5 times larger at TNF (16.2 +/- 1.5 MgC.ha-1 at BDFFP, versus 40.1 +/- 3.9 MgC.ha-1 at TNF). A model of current forest dynamics suggests that the BDFFP was close to carbon balance, and its size class structure approximated a steady state. The TNF, by contrast, showed rapid carbon accrual to live biomass (3.24 +/- 0.22 MgC.ha-1.a-1 in TNF, 2.59 +/- 0.16 MgC.ha-1.a-1 in BDFFP), which was more than offset by losses from large stocks of CWD, as well as ongoing shifts of biomass among size classes. This pattern in the TNF suggests recovery from a significant disturbance. The net loss of carbon from the TNF will likely last 10-15 years after the initial disturbance (controlled by the rate of decay of coarse woody debris), followed by uptake of carbon as the forest size class structure and composition continue to shift. The frequency and longevity of forests showing such disequilibruim dynamics within the larger matrix of the Amazon remains an essential question to understanding Amazonian carbon balance.

  8. Relations Between Spatial Distribution, Social Affiliations And Dominance Hierarchy In A Semi-Free Mandrill Population

    Directory of Open Access Journals (Sweden)

    Alexandre eNaud

    2016-05-01

    Full Text Available Although there exist advantages to group-living in comparison to a solitary lifestyle, costs and gains of group-living may be unequally distributed among group members. Predation risk, vigilance levels and food intake may be unevenly distributed across group spatial geometry and certain within-group spatial positions may be more or less advantageous depending on the spatial distribution of these factors. In species characterized with dominance hierarchy, high-ranking individuals are commonly observed in advantageous spatial position. However, in complex social systems, individuals can develop affiliative relationships that may balance the effect of dominance relationships in individual’s spatial distribution. The objective of the present study is to investigate how the group spatial distribution of a semi-free ranging colony of Mandrills relates to its social organization. Using spatial observations in an area surrounding the feeding zone, we tested the three following hypothesis: (1 does dominance hierarchy explain being observed in proximity or far from a food patch? (2 Do affiliative associations also explain being observed in proximity or far from a food patch? (3 Do the differences in rank in the group hierarchy explain being co-observed in proximity of a food patch? Our results showed that high-ranking individuals were more observed in proximity of the feeding zone while low-ranking individuals were more observed at the boundaries of the observation area. Furthermore, we observed that affiliative relationships were also associated with individual spatial distributions and explain more of the total variance of the spatial distribution in comparison with dominance hierarchy. Finally, we found that individuals observed at a same moment in proximity of the feeding zone were more likely to be distant in the hierarchy while controlling for maternal kinship, age and sex similarity. This study brings some elements about how affiliative networks

  9. The effects of spatial and temporal heterogeneity on the population dynamics of four animal species in a Danish landscape

    Directory of Open Access Journals (Sweden)

    Forchhammer Mads C

    2009-06-01

    Full Text Available Abstract Background Variation in carrying capacity and population return rates is generally ignored in traditional studies of population dynamics. Variation is hard to study in the field because of difficulties controlling the environment in order to obtain statistical replicates, and because of the scale and expense of experimenting on populations. There may also be ethical issues. To circumvent these problems we used detailed simulations of the simultaneous behaviours of interacting animals in an accurate facsimile of a real Danish landscape. The models incorporate as much as possible of the behaviour and ecology of skylarks Alauda arvensis, voles Microtus agrestis, a ground beetle Bembidion lampros and a linyphiid spider Erigone atra. This allows us to quantify and evaluate the importance of spatial and temporal heterogeneity on the population dynamics of the four species. Results Both spatial and temporal heterogeneity affected the relationship between population growth rate and population density in all four species. Spatial heterogeneity accounted for 23–30% of the variance in population growth rate after accounting for the effects of density, reflecting big differences in local carrying capacity associated with the landscape features important to individual species. Temporal heterogeneity accounted for 3–13% of the variance in vole, skylark and spider, but 43% in beetles. The associated temporal variation in carrying capacity would be problematic in traditional analyses of density dependence. Return rates were less than one in all species and essentially invariant in skylarks, spiders and beetles. Return rates varied over the landscape in voles, being slower where there were larger fluctuations in local population sizes. Conclusion Our analyses estimated the traditional parameters of carrying capacities and return rates, but these are now seen as varying continuously over the landscape depending on habitat quality and the mechanisms

  10. Population dynamics and spatial distribution of microbial species in multispecies biofilms under the action of direct electric current

    Institute of Scientific and Technical Information of China (English)

    CAO Hongbin; LI Xingang; WU Jinchuan; ZHONG Fangli; ZHANG Yi

    2003-01-01

    The metabolism, population dynamics and spatial distribution of nitrifying bacteria and heterotrophs in biofilms under the action of direct electric current were investigated by using the micro-slicing technique. The nitrification rate of nitrifying bacteria was severely inhibited by a current over 10 Am-2 at lower C/N ratios. Compared to heterotrophs, the nitrifying bacteria in the surface biofilms were severely inhibited, resulting in a significant decrease in bacterial density. An increase in current density narrowed the less current-sensitive inner biofilm region, and in addition the density of NO2-oxidizers decreased more significantly than that of NH4-oxidizers in the surface biofilms probably due to electrochemical reactions at the anode. However, the effect of current on both the population dynamics and the spatial distribution of the microbial species was less significant at larger C/N ratios.

  11. Food Plants Eaten by Amazonian Manatees (Trichechus inunguis, Mammalia : Sirenia)

    OpenAIRE

    Colares Ioni G.; Colares Elton P.

    2002-01-01

    To determine the feeding habits of the Amazonian manatee Trichechus inunguis in some Central Amazonian rivers and lakes, we compared plant epidermis found in the stomach contents and/or faeces of animals with a reference collection of plants present in the studied areas. Twenty five samples from digestive tracts of animals found dead and 25 faeces samples found floating were analyzed. From these samples, 24 aquatic macrophytes were identified. The Gramineae family was identified in 96% of the...

  12. Isozyme characterization of Capsicum accessions from the Amazonian Colombian collection

    OpenAIRE

    Lorena Quintero Barrera; Marisol Cudris García; Martha Cecilia Giraldo; Luz Marina Melgarejo

    2007-01-01

    Two hundred and sixty-one accessions of the genus Capsicum were obtained from the Colombian Amazonian germplasm bank at Amazonian Institute of Scientific Research (Sinchi) and were evaluated with five polymorphic enzymatic systems, including esterase (EST), peroxidase (PRX), 6-phosphogluconate dehydrogenase (6-PGDH), aspartate amino transferase (GOT), and malic enzyme (ME). Using a cluster analysis (UPGMA) the genetic variability of these accessions were characterized. Grouping of the species...

  13. The Population Density Gradient and the Spatial Structure of a Third World City: Nairobi, A Case Study

    OpenAIRE

    J A Kahimbaara

    1986-01-01

    A generalized Newling function to the fourth degree is used as a regionalizing technique to analyze population density data from the 1969 national census of Kenya in order to identify the spatial structure of Nairobi, Kenya's primate city. On the premise that the colonial origins of Nairobi encouraged residential segregation, first, by race during the colonial period and, second, by socio-economic class during the period of political independence, it is hypothesized: (1) that the density grad...

  14. Spatial Ecology and Population Dynamics of Tule Elk (Cervus elaphus nannodes) at Point Reyes National Seashore, California

    OpenAIRE

    Cobb, McCrea Andrew

    2010-01-01

    The tule elk (Cervus elaphus nannodes) was reintroduced to Point Reyes National Seashore, California in 1978. After exhibiting irruptive growth for 20 years, elk abundances have fluctuated. Three subpopulations of elk currently inhabit Pt. Reyes: a fenced subpopulation at high density; a free-ranging subpopulation in designated wilderness at low density; and a free-ranging subpopulation on active ranchland at low density. Little is known about the spatial ecology and population dynamics of...

  15. Microgeographic Spatial Structuring of Triatoma infestans (Hemiptera: Reduviidae) Populations Using Wing Geometric Morphometry in the Argentine Chaco

    OpenAIRE

    GASPE, M. S.; Schachter-Broide, J.; Gurevitz, J. M.; KITRON, U.; Gürtler, R. E.; Dujardin, J.P.

    2012-01-01

    We investigated the occurrence of spatial structuring in Triatoma infestans (Klug) (Hemiptera: Reduviidae) populations 12 yr after the last community-wide insecticide spraying campaign in rural Pampa del Indio, in the Gran Chaco of northeastern Argentina. In total, 172 male and 149 female right wings collected at 16 georeferenced sites with at least 10 individuals of the same sex were analyzed using geometric morphometry. Mean female body length and wing centroid size (CS) were significantly ...

  16. Les stratégies spatiales de la population haïtienne à Miami

    Directory of Open Access Journals (Sweden)

    Cédric Audebert

    2008-02-01

    Full Text Available Le schéma migratoire haïtien s’est traduit par la genèse d’un champ migratoire international entre le pays d’origine et Miami, où la population d’origine haïtienne a enregistré une croissance rapide. Dans une métropole floridienne marquée par une forte ségrégation « ethno-raciale » et socio-économique, les nouveaux venus se sont installés à l’origine dans les quartiers noirs centraux paupérisés. Les incidences de la politique migratoire fédérale sont apparues contrastées, occasionnant le repli sur soi des immigrants à Little Haiti lorsqu’elle était défavorable ou rendant possible la mobilité résidentielle dans une conjoncture d’assouplissement de la législation. Ultérieurement, la complexité croissante de l’espace de l’immigration haïtienne, caractérisé par une évolution rapide de son étendue et de ses formes, s’est manifestée par une dichotomie marquée entre l’« enclave » traditionnelle et les nouveaux espaces d’installation en banlieue. Résultat d’une dynamique d’agrégation autant choisie que contrainte, la concentration spatiale des Haïtiens à Miami s’est traduite par la genèse de secteurs d’implantation privilégiée, terrains favorables à la mise en place de processus de territorialisation complexes. L’apprentissage mental et fonctionnel de l’espace vise à faire sienne la terre d’immigration et à la doter de sens, et apparaît comme le préalable à la mise en place de stratégies collectives de territorialisation. La « prise de possession » d’une portion de l’aire métropolitaine et son affectation à des activités sociales, commerciales et de représentation politique visent à assurer la pérennité du lien communautaire haïtien en créant de la cohésion, de la solidarité et de la socialité.Haitian emigration has evolved within the growing dependency of Haiti from the United States throughout the XXth century. The Haitian migratory pattern

  17. Spatial analysis of environment and population at risk of natural gas fracking in the state of Pennsylvania, USA.

    Science.gov (United States)

    Meng, Qingmin

    2015-05-15

    Hydraulic fracturing, also known as fracking, has been increasing exponentially across the United States, which holds the largest known shale gas reserves in the world. Studies have found that the high-volume horizontal hydraulic fracturing process (HVHFP) threatens water resources, harms air quality, changes landscapes, and damages ecosystems. However, there is minimal research focusing on the spatial study of environmental and human risks of HVHFP, which is necessary for state and federal governments to administer, regulate, and assess fracking. Integrating GIS and spatial kernel functions, we study the presently operating fracking wells across the state of Pennsylvania (PA), which is the main part of the current hottest Marcellus Shale in US. We geographically process the location data of hydraulic fracturing wells, 2010 census block data, urbanized region data, railway data, local road data, open water data, river data, and wetland data for the state of PA. From this we develop a distance based risk assessment in order to understand the environmental and urban risks. We generate the surface data of fracking well intensity and population intensity by integrating spatial dependence, semivariogram modeling, and a quadratic kernel function. The surface data of population risk generated by the division of fracking well intensity and population intensity provide a novel insight into the local and regional regulation of hydraulic fracturing activities in terms of environmental and health related risks due to the proximity of fracking wells. PMID:25727517

  18. The coupling of oligotrich ciliate populations and hydrography in the East China Sea: spatial and temporal variations

    Science.gov (United States)

    Chiang, Kuo-Ping; Lin, Chiu-Yi; Lee, Chung-Hsien; Shiah, Fuh-Kwo; Chang, Jeng

    2003-03-01

    Variations in the spatial and temporal distribution of oligotrich ciliate populations in the East China Sea were investigated during four cruises of the R/V Ocean Researcher I between December 1997 and October 1998. Over the entire continental shelf, a seasonal cycle was found with a distinct 3-5-fold increase in the abundance of oligotrich ciliates in summer. This increase appeared to be induced by the tremendous summertime runoff from the Changjiang. A radial-type spatial distribution pattern also was observed in summer, with population densities higher toward the Changjiang plume but highest of all in the margins of the plume. In spring and fall, the spatial distribution of the oligotrich ciliates was closely correlated to the abundance of cyanobacterium Synechococcus. In summer in the plume region, mixotrophic ciliates accounted for over 50% of the total ciliate population, compared to less than 30% outside the plume or that in other seasons. We propose a model in which these ciliates constitute part of the pathway through which the particulate and dissolved organic carbon in the runoff water is incorporated into the oceanic food web.

  19. Populational fluctuation and spatial distribution of Alphitobius diaperinus (Panzer) (Coleoptera; Tenebrionidae) in a poultry house, Cascavel, Parana state, Brazil.

    Science.gov (United States)

    Chernaki-Leffer, A M; Almeida, L M; Sosa-Gómez, D R; Anjos, A; Vogado, K M

    2007-05-01

    Knowledge of the population fluctuation and spatial distribution of pests is fundamental for establishing an appropriate control method. The population fluctuation and spatial distribution of the Alphitobius diaperinus in a poultry house in Cascavel, in the state of Parana, Brazil, was studied between October, 2001 and October 2002. Larvae and adults of the lesser mealworm were sampled weekly using Arends tube traps (n = 22) for six consecutive flock grow-outs. The temperature of the litter and of the poultry house was measured at the same locations of the tube traps. Beetle numbers increased continuously throughout all the sampling dates (average 5,137 in the first week and 18,494 insects on the sixth week). Significantly greater numbers of larvae were collected than adults (1 to 20 times in 95% of the sampling points). There was no correlation between temperature and the number of larvae and adults collected, therefore no fluctuation was observed during the sampling period. The population growth was correlated to litter re-use. The highest temperatures were observed in deep litter. The spatial distribution of larvae and adults in the poultry house was heterogeneous during the whole period of evaluation. Results suggest that monitoring in poultry houses is necessary prior to adopting and evaluating control measures due to the great variability of the insect distribution in the poultry house. PMID:17876430

  20. From locational fundamentals to increasing returns: the spatial concentration of population in Spain, 1787-2000

    Science.gov (United States)

    Ayuda, María Isabel; Collantes, Fernando; Pinilla, Vicente

    2010-03-01

    Why is population not evenly distributed throughout a country’s territory? This paper focuses on the case of Spain, in order to empirically test two complementary theoretical explanations: (a) first nature advantages or locational fundamentals; and (b) second nature advantages or increasing returns. We estimate population density and population growth equations for the case of Spain between 1787 and 2000. Our results suggest that locational fundamentals explain the distribution of population prior to industrialization and that industrialization reinforced the pre-existing regional population disparities, especially as the share of increasing-returns sectors in the Spanish economy became significant. Finally, we perform an ANOVA analysis which shows that although in the pre-industrial economy first nature advantages were the most important in explaining the growth in provincial population densities, these were progressively superseded by the influence of first via second nature effects.

  1. Spatial and temporal variation of the Synechococcus population in the East China Sea and its contribution to phytoplankton biomass

    Science.gov (United States)

    Chiang, Kuo-Ping; Kuo, Min-Chieh; Chang, Jeng; Wang, Ru-Huey; Gong, Gwo-Ching

    2002-01-01

    Variations in the spatial and temporal distribution of the Synechococcus population in the East China Sea were investigated in five cruises of the R/V Ocean Research I between May 1996 and October 1998. On the continental shelf, a two-phased (warm >20°C; and cold <20°C) seasonal cycle with 10-fold variation was found in the Synechococcus population. In the cold season (winter to late spring), when temperature is probably a limiting factor, a low density Synechococcus population was homogeneously distributed over the entire continental shelf. A dome-type spatial distribution pattern appeared in summer, that is, population densities were high toward the middle of the sea. This area of higher density moved toward the outer shelf in fall. No seasonal variation was found in the Coastal Water, probably because in summer the low transmission means that light is limited below the surface. The average carbon biomass of Synechococcus in the East China Sea ranged from 0.09 (early spring) to 0.90 gC m -2 (fall). Based on carbon biomass, Synechococcus accounted for less than 25% of the total photosynthetic plankton in cold season and about 50% in the warm season. Our results suggest that the cyanobacterium Synechococcus is a major contributor to the seasonal variation of phytoplankton in the East China Sea.

  2. Fish are central in the diet of Amazonian riparians: should we worry about their mercury concentrations?

    International Nuclear Information System (INIS)

    The Amazon rain forest extends over an area of 7.8x106 km2 in nine countries. It harbors a diverse human population distributed in dense cities and isolated communities with extreme levels of infrastructure. Amazonian forest people, either autochthons or frontier riparians (ribeirinhos) living in isolated areas, share the same environment for survival and nutritional status. The peculiarities of the hydrological cycle determine disease patterns, agricultural conditions, and food availability. Feeding strategies depend heavily on cassava products and fish. These two foods carry toxic substances such as linamarin (naturally present in cassava) and monomethyl mercury (MMHg) (bioconcentrated in fish flesh) that cause neurotoxic diseases in other parts of the world but not in Amazonia, where neurotoxic cases of food origin are rare and not related to these staples. While cassava detoxification processes may partly explain its safe consumption, the Hg concentrations in Amazonian fish are within traditionally safe limits for this population and contribute to an important metabolic interaction with cassava. The gold rush of the 1970s and 1980s brought large-scale environmental disruption and physical destruction of ecosystems at impact points, along with a heavy discharge of metallic Hg. The discharged Hg has not yet impacted on MMHg concentrations in fish or in hair of fish consumers. Hair Hg concentration, used as a biomarker of fish consumption, indicates that the Amazonian riparians are acquiring an excellent source of protein carrying important nutrients, the lack of which could aggravate their existing health problems. Therefore, in a scenario of insufficient health services and an unhealthy environment, food habits based on fish consumption are part of a successful survival strategy and recommendations for changes are not yet justifiable

  3. Populações de aranhas errantes do gênero Ctenus em fragmentos florestais na Amazônia Central Populations of Ctenus wandering spiders in Amazonian forest fragments

    Directory of Open Access Journals (Sweden)

    Luiz Augusto Macedo Mestre

    2008-01-01

    ções ambientais.Ctenus is a genus of wandering spiders abundant in Neotropical and African rainforests and is becoming a model organism to understand the biology of predators in the leaf litter fauna. We compared abundance, sex ratio, seasonality and size dimorphism in populations of four species of medium sized wandering spiders, Ctenus amphora, C. crulsi, C. manauara and C. villasboasi in primary forests, fragments with different areas, their borders and secondary forests near them. This study was conducted between February and July 1999, in a terra-firme (non-flooded tropical rain forest, in central Amazonia. The spiders were measured and counted in transects of 250x5 m or 500x5 m in three secondary forest sites, four fragments of primary forest of 1 ha, three of 10 ha, two of 100 ha and four reserves of continuous forest (larger than 10.000 ha. There was a significant predominance of females in two species (C. amphora- 74% and C. crulsi- 65%, sexual dimorphism significant in three species (C. amphora, C. crulsi, and C. manauara, and temporal variation of the abundance for the four species. These results corroborate and complement tendencies from previous studies. There were no statistical differences between spider abundance in interior, borders and between reserves of different areas. Effects of border and size of fragments on the Ctenus spider populations are smaller than the previously observed variations among different habitats in the forest interior. There was no difference in spider size captured in small reserves, large reserves, edges, and continuous forests sites. Comparing these results with other study in the same sites, we conclude that the effects of fragmentation in Ctenus spiders decrease with second grown regeneration, resulting in a rapid reply of these species to habitat modifications.

  4. Lineage divergence detected in the malaria vector Anopheles marajoara (Diptera: Culicidae in Amazonian Brazil

    Directory of Open Access Journals (Sweden)

    Povoa Marinete M

    2010-10-01

    Full Text Available Abstract Background Cryptic species complexes are common among anophelines. Previous phylogenetic analysis based on the complete mtDNA COI gene sequences detected paraphyly in the Neotropical malaria vector Anopheles marajoara. The "Folmer region" detects a single taxon using a 3% divergence threshold. Methods To test the paraphyletic hypothesis and examine the utility of the Folmer region, genealogical trees based on a concatenated (white + 3' COI sequences dataset and pairwise differentiation of COI fragments were examined. The population structure and demographic history were based on partial COI sequences for 294 individuals from 14 localities in Amazonian Brazil. 109 individuals from 12 localities were sequenced for the nDNA white gene, and 57 individuals from 11 localities were sequenced for the ribosomal DNA (rDNA internal transcribed spacer 2 (ITS2. Results Distinct A. marajoara lineages were detected by combined genealogical analysis and were also supported among COI haplotypes using a median joining network and AMOVA, with time since divergence during the Pleistocene (COI sequences at the 3' end were more variable, demonstrating significant pairwise differentiation (3.82% compared to the more moderate 2.92% detected by the Folmer region. Lineage 1 was present in all localities, whereas lineage 2 was restricted mainly to the west. Mismatch distributions for both lineages were bimodal, likely due to multiple colonization events and spatial expansion (~798 - 81,045 ya. There appears to be gene flow within, not between lineages, and a partial barrier was detected near Rio Jari in Amapá state, separating western and eastern populations. In contrast, both nDNA data sets (white gene sequences with or without the retention of the 4th intron, and ITS2 sequences and length detected a single A. marajoara lineage. Conclusions Strong support for combined data with significant differentiation detected in the COI and absent in the nDNA suggest that

  5. Spatial pattern formation and intraspecific competition of anabasis aphylla l. population in the diluvial fan of junggar basin, nw china

    International Nuclear Information System (INIS)

    Using conventional nearest neighbour analysis and Ripley's L-function, the goal of this study was to analyze spatial patterns of Anabasis aphylla plants in order to investigate underlying competitive processes that shape the population spatial structure from diluvial fan in Junggar Basin, NW China. We found that the spatial patterns of all growth stages were aggregated in the three study plots, and seedling and juvenile plants were more aggregated than expected by chance. Positive associations among growth stages of A. aphylla population were found at a small scale while negative associations of seedling and juvenile relative to adult plants were shown at a larger scale. The processes such as dispersal, seedling establishment, environmental heterogeneity, plant interactions and disturbance may have acted individually or in concert with other processes to produce the aggregated patterns and competitive relationship. Moreover, these findings suggested that the aggregated distribution and the competitive interaction between A. aphylla plants in the diluvial fan reflected not only in mortality, but also in decreased performance (smaller canopy) that was an important characteristic of drought-enduring plant, thus preventing a regular distribution pattern. (author)

  6. Bridging the divide: Middle Eastern walls and fences and the spatial governance of problem populations

    NARCIS (Netherlands)

    P. Pallister-Wilkins

    2015-01-01

    Building on a long history of spatial control through walling in the region, walls and fences have been built in the Middle East in recent years to undertake a range of practices. Gated communities, residential and security compounds, anti-migrant walls, separation barriers and counter-insurgency fe

  7. Hierarchical spatial genetic structure in a distinct population segment of greater sage-grouse

    Science.gov (United States)

    Oyler-McCance, Sara J.; Casazza, Michael L.; Fike, Jennifer A.; Coates, Peter S.

    2014-01-01

    Greater sage-grouse (Centrocercus urophasianus) within the Bi-State Management Zone (area along the border between Nevada and California) are geographically isolated on the southwestern edge of the species’ range. Previous research demonstrated that this population is genetically unique, with a high proportion of unique mitochondrial DNA (mtDNA) haplotypes and with significant differences in microsatellite allele frequencies compared to populations across the species’ range. As a result, this population was considered a distinct population segment (DPS) and was recently proposed for listing as threatened under the U.S. Endangered Species Act. A more comprehensive understanding of the boundaries of this genetically unique population (where the Bi-State population begins) and an examination of genetic structure within the Bi-State is needed to help guide effective management decisions. We collected DNA from eight sampling locales within the Bi-State (N = 181) and compared those samples to previously collected DNA from the two most proximal populations outside of the Bi-State DPS, generating mtDNA sequence data and amplifying 15 nuclear microsatellites. Both mtDNA and microsatellite analyses support the idea that the Bi-State DPS represents a genetically unique population, which has likely been separated for thousands of years. Seven mtDNA haplotypes were found exclusively in the Bi-State population and represented 73 % of individuals, while three haplotypes were shared with neighboring populations. In the microsatellite analyses both STRUCTURE and FCA separate the Bi-State from the neighboring populations. We also found genetic structure within the Bi-State as both types of data revealed differences between the northern and southern part of the Bi-State and there was evidence of isolation-by-distance. STRUCTURE revealed three subpopulations within the Bi-State consisting of the northern Pine Nut Mountains (PNa), mid Bi-State, and White Mountains (WM) following a

  8. Dynamics of weed populations: spatial patter formation and implications for control.

    OpenAIRE

    Wallinga, J.

    1998-01-01

    Modelling studies were carried out to analyse spatio-temporal dynamics of annual weed populations and to identify the key factors that determine the long-term herbicide use of weed control programmes. Three different weed control programmes were studied.In the first weed control programme, herbicides are applied to the whole field only if the weed density exceeds a threshold value, otherwise there is no control at all. The dynamics of a weed population subjected to such a 'threshold control p...

  9. The Fleming-Viot limit of an interacting spatial population with fast density regulation

    CERN Document Server

    Gupta, Ankit

    2012-01-01

    We consider population models in which the individuals reproduce, die and also migrate in space. The population size scales according to some parameter $N$, which can have different interpretations depending on the context. Each individual is assigned a mass of 1/N and the total mass in the system is called population density. The dynamics has an intrinsic density regulation mechanism that drives the population density towards an equilibrium. We show that under a timescale separation between the slow migration mechanism and the fast density regulation mechanism, the population dynamics converges to a Fleming-Viot process as the scaling parameter $N \\to \\infty$. We first prove this result for a basic model in which the birth and death rates can only depend on the population density. In this case we obtain a neutral Fleming-Viot process. We then extend this model by including position-dependence in the birth and death rates, as well as, offspring dispersal and immigration mechanisms. We show how these extension...

  10. Mapping the Centimeter-Scale Spatial Variability of PAHs and Microbial Populations in the Rhizosphere of Two Plants.

    Directory of Open Access Journals (Sweden)

    Amélia Bourceret

    Full Text Available Rhizoremediation uses root development and exudation to favor microbial activity. Thus it can enhance polycyclic aromatic hydrocarbon (PAH biodegradation in contaminated soils. Spatial heterogeneity of rhizosphere processes, mainly linked to the root development stage and to the plant species, could explain the contrasted rhizoremediation efficiency levels reported in the literature. Aim of the present study was to test if spatial variability in the whole plant rhizosphere, explored at the centimetre-scale, would influence the abundance of microorganisms (bacteria and fungi, and the abundance and activity of PAH-degrading bacteria, leading to spatial variability in PAH concentrations. Two contrasted rhizospheres were compared after 37 days of alfalfa or ryegrass growth in independent rhizotron devices. Almost all spiked PAHs were degraded, and the density of the PAH-degrading bacterial populations increased in both rhizospheres during the incubation period. Mapping of multiparametric data through geostatistical estimation (kriging revealed that although root biomass was spatially structured, PAH distribution was not. However a greater variability of the PAH content was observed in the rhizosphere of alfalfa. Yet, in the ryegrass-planted rhizotron, the Gram-positive PAH-degraders followed a reverse depth gradient to root biomass, but were positively correlated to the soil pH and carbohydrate concentrations. The two rhizospheres structured the microbial community differently: a fungus-to-bacterium depth gradient similar to the root biomass gradient only formed in the alfalfa rhizotron.

  11. Development of a population of cancer cells: Observation and modeling by a Mixed Spatial Evolutionary Games approach.

    Science.gov (United States)

    Świerniak, Andrzej; Krześlak, Michał; Student, Sebastian; Rzeszowska-Wolny, Joanna

    2016-09-21

    Living cells, like whole living organisms during evolution, communicate with their neighbors, interact with the environment, divide, change their phenotypes, and eventually die. The development of specific ways of communication (through signaling molecules and receptors) allows some cellular subpopulations to survive better, to coordinate their physiological status, and during embryonal development to create tissues and organs or in some conditions to become tumors. Populations of cells cultured in vitro interact similarly, also competing for space and nutrients and stimulating each other to better survive or to die. The results of these intercellular interactions of different types seem to be good examples of biological evolutionary games, and have been the subjects of simulations by the methods of evolutionary game theory where individual cells are treated as players. Here we present examples of intercellular contacts in a population of living human cancer HeLa cells cultured in vitro and propose an evolutionary game theory approach to model the development of such populations. We propose a new technique termed Mixed Spatial Evolutionary Games (MSEG) which are played on multiple lattices corresponding to the possible cellular phenotypes which gives the possibility of simulating and investigating the effects of heterogeneity at the cellular level in addition to the population level. Analyses performed with MSEG suggested different ways in which cellular populations develop in the case of cells communicating directly and through factors released to the environment. PMID:27216640

  12. Spatial and temporal variation in population genetic structure of wild Nile tilapia (Oreochromis niloticus across Africa

    Directory of Open Access Journals (Sweden)

    Bezault Etienne

    2011-12-01

    Full Text Available Abstract Background Reconstructing the evolutionary history of a species is challenging. It often depends not only on the past biogeographic and climatic events but also the contemporary and ecological factors, such as current connectivity and habitat heterogeneity. In fact, these factors might interact with each other and shape the current species distribution. However, to what extent the current population genetic structure reflects the past and the contemporary factors is largely unknown. Here we investigated spatio-temporal genetic structures of Nile tilapia (Oreochromis niloticus populations, across their natural distribution in Africa. While its large biogeographic distribution can cause genetic differentiation at the paleo-biogeographic scales, its restricted dispersal capacity might induce a strong genetic structure at micro-geographic scales. Results Using nine microsatellite loci and 350 samples from ten natural populations, we found the highest genetic differentiation among the three ichthyofaunal provinces and regions (Ethiopian, Nilotic and Sudano-Sahelian (RST = 0.38 - 0.69. This result suggests the predominant effect of paleo-geographic events at macro-geographic scale. In addition, intermediate divergences were found between rivers and lakes within the regions, presumably reflecting relatively recent interruptions of gene flow between hydrographic basins (RST = 0.24 - 0.32. The lowest differentiations were observed among connected populations within a basin (RST = 0.015 in the Volta basin. Comparison of temporal sample series revealed subtle changes in the gene pools in a few generations (F = 0 - 0.053. The estimated effective population sizes were 23 - 143 and the estimated migration rate was moderate (m ~ 0.094 - 0.097 in the Volta populations. Conclusions This study revealed clear hierarchical patterns of the population genetic structuring of O. niloticus in Africa. The effects of paleo-geographic and climatic events were

  13. Spatial variation in population structure and its relation to movement and the potential for dispersal in a model intertidal invertebrate.

    Directory of Open Access Journals (Sweden)

    Trevor T Bringloe

    Full Text Available Dispersal, the movement of an individual away from its natal or breeding ground, has been studied extensively in birds and mammals to understand the costs and benefits of movement behavior. Whether or not invertebrates disperse in response to such attributes as habitat quality or density of conspecifics remains uncertain, due in part to the difficulties in marking and recapturing invertebrates. In the upper Bay of Fundy, Canada, the intertidal amphipod Corophium volutator swims at night around the new or full moon. Furthermore, this species is regionally widespread across a large spatial scale with site-to-site variation in population structure. Such variation provides a backdrop against which biological determinants of dispersal can be investigated. We conducted a large-scale study at nine mudflats, and used swimmer density, sampled using stationary plankton nets, as a proxy for dispersing individuals. We also sampled mud residents using sediment cores over 3 sampling rounds (20-28 June, 10-17 July, 2-11 August 2010. Density of swimmers was most variable at the largest spatial scales, indicating important population-level variation. The smallest juveniles and large juveniles or small adults (particularly females were consistently overrepresented as swimmers. Small juveniles swam at most times and locations, whereas swimming of young females decreased with increasing mud presence of young males, and swimming of large juveniles decreased with increasing mud presence of adults. Swimming in most stages increased with density of mud residents; however, proportionally less swimming occurred as total mud resident density increased. We suggest small juveniles move in search of C. volutator aggregations which possibly act as a proxy for better habitat. We also suggest large juveniles and small adults move if potential mates are limiting. Future studies can use sampling designs over large spatial scales with varying population structure to help

  14. Ecological Complexity in a Coffee Agroecosystem: Spatial Heterogeneity, Population Persistence and Biological Control

    OpenAIRE

    Heidi Liere; Doug Jackson; John Vandermeer

    2012-01-01

    BACKGROUND: Spatial heterogeneity is essential for the persistence of many inherently unstable systems such as predator-prey and parasitoid-host interactions. Since biological interactions themselves can create heterogeneity in space, the heterogeneity necessary for the persistence of an unstable system could be the result of local interactions involving elements of the unstable system itself. METHODOLOGY/PRINCIPAL FINDINGS: Here we report on a predatory ladybird beetle whose natural history ...

  15. Spatial and temporal country-wide survey of temephos resistance in Brazilian populations of Aedes aegypti

    OpenAIRE

    Mateus Chediak; Fabiano G Pimenta Jr; Giovanini E Coelho; Ima A Braga; José Bento P Lima; Karina Ribeiro LJ Cavalcante; Lindemberg C. Sousa; Maria Alice V Melo-Santos; Maria de Lourdes da G Macoris; Ana Paula de Araújo; Ayres, Constância Flávia J; Maria Teresa M Andrighetti; Ricristhi Gonçalves de A Gomes; Campos, Kauara B; Raul Narciso C Guedes

    2016-01-01

    The organophosphate temephos has been the main insecticide used against larvae of the dengue and yellow fever mosquito (Aedes aegypti) in Brazil since the mid-1980s. Reports of resistance date back to 1995; however, no systematic reports of widespread temephos resistance have occurred to date. As resistance investigation is paramount for strategic decision-making by health officials, our objective here was to investigate the spatial and temporal spread of temephos resistance in Ae. aegypti in...

  16. On an age and spatially structured population model for Proteus Mirabilis swarm-colony development

    OpenAIRE

    Laurençot, Philippe; Walker, Christoph

    2007-01-01

    Proteus mirabilis are bacteria that make strikingly regular spatial-temporal patterns on agar surfaces. In this paper we investigate a mathematical model that has been shown to display these structures when solved numerically. The model consists of an ordinary differential equation coupled with a partial differential equation involving a first-order hyperbolic aging term together with nonlinear degenerate diffusion. The system is shown to admit global weak solutions.

  17. Globodera rostochiensis Population Density Decline in Relation to Spatial Distribution around Resistant Potato Plants

    OpenAIRE

    LaMondia, J. A.

    1986-01-01

    Golden nematode, Globodera rostochiensis (GN) population decline under resistant potatoes was related to cyst distance from plants 23 cm apart in rows 92 cm apart. GN decline, determined by sampling an infested field planted to the resistant cultivar 'Yankee Chipper', was 81.8% in cores 11.5 cm from plants within rows. Decline was 27.4% at 23 cm from plants between rows and 36.6% at 46 cm. Population decline of juveniles in cysts added to soil in bags was 90.3% for cysts 11.5 cm from plants w...

  18. Produção e predação de frutos em Aniba rosaeodora Ducke var. amazonica Ducke (Lauraceae em sistema de plantio sob floresta de terra firme na Amazônia Central Harvesting and fruit predation of a Aniba rosaeodora Ducke var. amazonica Ducke (Lauraceae ex situ tree population in a central Amazonian upland forest

    Directory of Open Access Journals (Sweden)

    Wilson Roberto Spironello

    2004-12-01

    Full Text Available O pau-rosa (Aniba rosaeodora vem sendo usado desde o século passado para extração de linalol, produto usado como fixador de perfumes. Por causa do extrativismo houve redução drástica em suas populações naturais. Somando a este fato, esta espécie possui padrão irregular de frutificação e, quando frutifica, os seus frutos são consumidos por animais. Estes aspectos foram estudados utilizando uma população de plantio sob sombra parcial de floresta primária. A produtividade das árvores variou de 40 a 1.600 frutos (n = 21 árvores. No geral, cerca de 42,5% foram removidos por frugívoros (6.770 frutos, n = 10 árvores. Dos frutos não removidos, 0,5% foram predados por vertebrados, 81,5% continham larvas de insetos, variando de 36-96% entre indivíduos. Uma espécie de Coleoptera ataca os frutos em estádio imaturo, enquanto outra (Heilipus sp. e uma espécie de Lepidoptera atacam os frutos em estádio final de desenvolvimento. Os resultados projetam perda de 59,5% dos frutos (54,5% por insetos passíveis de coleta. Considerando a importância econômica do pau-rosa faz-se necessário aumentar a disponibilidade de sementes para planos de manejo da espécie. Para se atingir tais objetivos são necessárias algumas medidas: 1 coleta prematura de frutos para maturação em laboratório; 2 utilização de métodos de controle de insetos adultos (em plantios e larvas (em frutos atacados; e 3 estudos de seleção genética para identificar plantas com maior resistência natural a pragas e doenças.The rosewood tree (Aniba rosaeodora has been exploited for linalol, a product used as a fixative by the perfume industry. As a result, its population has decreased to the point that it is at risk of extinction in some Amazonian areas. In addition, the species has an irregular phenological pattern and its fruits are a food source for animals. This study focused on the use an ex situ population planted under partial forest shade. The fruit set

  19. Geographic and genetic population differentiation of the Amazonian chocolate tree

    Science.gov (United States)

    Numerous collecting expeditions of Theobroma cacao L. germplasm hae been undertaken in Latin-America. However, this germplasm has not contributed to cacao improvement because its relationship to cultivated selections was poorly understood. Germplasm labeling errors have impeded breeding and confound...

  20. Spatial relationship between human population density, land use intensity and biodiversity in the Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Vačkář, David; Chobot, K.; Orlitová, E.

    2012-01-01

    Roč. 27, č. 9 (2012), s. 1279-1290. ISSN 0921-2973 Institutional support: RVO:67179843 Keywords : species richness * landscape diversity * human population density * human appropriation of net primary production * Czech Republic Subject RIV: EH - Ecology, Behaviour Impact factor: 2.897, year: 2012

  1. Effect of culling and vaccination on bovine tuberculosis infection in a European badger (Meles meles) population by spatial simulation modelling.

    Science.gov (United States)

    Abdou, Marwa; Frankena, Klaas; O'Keeffe, James; Byrne, Andrew W

    2016-03-01

    The control of bovine tuberculosis (bTB) in cattle herds in the Republic of Ireland (ROI) is partially hindered by spill-back infection from wild badgers (Meles meles). The aim of this study was to determine the relative effects of interventions (combinations of culling and/or vaccination) on bTB dynamics in an Irish badger population. A spatial agent-based stochastic simulation model was developed to evaluate the effect of various control strategies for bovine tuberculosis in badgers: single control strategies (culling, selective culling, vaccination, and vaccine baits), and combined strategies (Test vaccinate/cull (TVC)), split area approaches using culling and vaccination, or selective culling and vaccination, and mixed scenarios where culling was conducted for five years and followed by vaccination or by a TVC strategy. The effect of each control strategy was evaluated over a 20-year period. Badger control was simulated in 25%, 50%, and 75% area (limited area strategy) or in the entire area (100%, wide area strategy). For endemic bTB, a culling strategy was successful in eradicating bTB from the population only if applied as an area-wide strategy. However, this was achieved only by risking the extinction of the badger population. Selective culling strategies (selective culling or TVC) mitigated this negative impact on the badger population's viability. Furthermore, both strategies (selective culling and TVC) allowed the badger population to recover gradually, in compensation for the population reduction following the initial use of removal strategies. The model predicted that vaccination can be effective in reducing bTB prevalence in badgers, when used in combination with culling strategies (i.e. TVC or other strategies). If fecundity was reduced below its natural levels (e.g. by using wildlife contraceptives), the effectiveness of vaccination strategies improved. Split-area simulations highlighted that interventions can have indirect effects (e.g. on

  2. Population ecology of Paepalanthus polyanthus (Bong.) Kunth: temporal variation in the pattern of spatial distribution

    OpenAIRE

    Tânia Tarabini Castellani; Karla Zanenga Scherer

    2004-01-01

    The temporal variation in density and pattern of spatial distribution of Paepalanthus polyanthus (BONG.) Kunth (Eriocaulaceae) were evaluated at a determinate sand dune. This study was carried out over a period of five years, at three permanent plots of 25m2 in a sand dune slack at Joaquina Beach, Florianópolis, SC, Brazil. There were strong density fluctuations throughout these years. In areas 1, 2 and 3, the densities changed from 10.4, 2.2 and 1.8 plants/m2 in December 1986 to 75.8, 11.4 a...

  3. Antinociceptive activity of Amazonian Copaiba oils.

    Science.gov (United States)

    Gomes, Niele Matos; Rezende, Claudia Moraes; Fontes, Silvia Paredes; Matheus, Maria Eline; Fernandes, Patricia Dias

    2007-02-12

    Copaiba oil resins are extensively commercialized in Brazil as capsules or crude oil and used as anti-inflammatory and anti-septic. Comparative pharmacological studies between different species of Copaiba oils are scarce. In the present work we compared the antinociceptive activity of two Amazonian Copaiba oils (Copaifera multijuga Hayne and Copaifera reticulata Ducke, Fabaceae) administered by oral route using peripheral (acetic acid-induced abdominal writhing and formalin), spinal (tail flick) and supra-spinal (hot plate) models. Results demonstrated that the Copaiba oils did not develop toxic effects. Doses ranging from 30 to 150 mg/kg were enough to significantly develop peripheral antinociceptive effect. All Copaiba oils demonstrate central activity but with less effect on supra-spinal regions of the brain. Administration of the opioid receptor antagonist, naloxone completely inhibited the antinociceptive effect induced by both Copaiba oils. Our results indicate that Copaiba oils demonstrate peripheral and central antinociceptive effect. This new comprobate effect may be useful in the treatment of algesic disorders. PMID:17029841

  4. Methane Dynamics in Large Amazonian Rivers

    Science.gov (United States)

    Sawakuchi, H. O.; Bastviken, D.; Sawakuchi, A. O.; Borges, C. D.; Tsai, S. M.; Ward, N. D.; Richey, J. E.; Ballester, M. V.; Krusche, A. V.

    2014-12-01

    The emission of methane (CH4) from rivers is not always included in the greehouse gas budget for inland waters, mainly due to a lack of information available for these systems. Unraveling the dynamics that control fluvial CH4 sources and sinks is critical for understanding the contribution of CH4 to riverine and global carbon budgets. Here, we present estimates of CH4 sources and sinks in numerous large Amazonian rivers during periods of high and low discharge. Calculations based on CH4 flux measurements and isotopic data (δ13CH4) of dissolved CH4 and bubbles in riverbed sediments were performed to assess the sources and sinks of river water CH4. Molecular analysis (qPCR) in river water samples was used to determine methanotrophic bacterial density. Methane-oxidizing bacterial counts were compared to oxidation estimates in order to assess the relationship between methane sinks and in situ bacterial communities. In general, rivers that had an enriched δ13CH4 in the water also had a higher density of methanotrophic bacteria in the water column, illustrating an important control on CH4 availability and flux related to physicochemical factors that control the abundance and activity of methanotrophic bacteria. Further, we observed a distinct relationship between the type of river (e.g. clear, white, or black water) and the flux of methane from the water column.

  5. Phthalate pollution in an Amazonian rainforest.

    Science.gov (United States)

    Lenoir, Alain; Boulay, Raphaël; Dejean, Alain; Touchard, Axel; Cuvillier-Hot, Virginie

    2016-08-01

    Phthalates are ubiquitous contaminants and endocrine-disrupting chemicals that can become trapped in the cuticles of insects, including ants which were recognized as good bioindicators for such pollution. Because phthalates have been noted in developed countries and because they also have been found in the Arctic, a region isolated from direct anthropogenic influence, we hypothesized that they are widespread. So, we looked for their presence on the cuticle of ants gathered from isolated areas of the Amazonian rainforest and along an anthropogenic gradient of pollution (rainforest vs. road sides vs. cities in French Guiana). Phthalate pollution (mainly di(2-ethylhexyl) phthalate (DEHP)) was higher on ants gathered in cities and along road sides than on those collected in the pristine rainforest, indicating that it follows a human-mediated gradient of disturbance related to the use of plastics and many other products that contain phthalates in urban zones. Their presence varied with the ant species; the cuticle of Solenopsis saevissima traps higher amount of phthalates than that of compared species. However, the presence of phthalates in isolated areas of pristine rainforests suggests that they are associated both with atmospheric particles and in gaseous form and are transported over long distances by wind, resulting in a worldwide diffusion. These findings suggest that there is no such thing as a "pristine" zone. PMID:27372101

  6. Population ecology of Paepalanthus polyanthus (Bong. Kunth: temporal variation in the pattern of spatial distribution

    Directory of Open Access Journals (Sweden)

    Tânia Tarabini Castellani

    2004-11-01

    Full Text Available The temporal variation in density and pattern of spatial distribution of Paepalanthus polyanthus (BONG. Kunth (Eriocaulaceae were evaluated at a determinate sand dune. This study was carried out over a period of five years, at three permanent plots of 25m2 in a sand dune slack at Joaquina Beach, Florianópolis, SC, Brazil. There were strong density fluctuations throughout these years. In areas 1, 2 and 3, the densities changed from 10.4, 2.2 and 1.8 plants/m2 in December 1986 to 75.8, 11.4 and 45.6 plants/m2 in December 1991. Area 3, situated on an elevated site, presented greater variation in density, with no live plants in December 1989 and 102.2 plants/m2 at the recruitment observed in May 1990. Despite these density fluctuations, the pattern of spatial distribution was always aggregated (Id>1, P<0.05. The greatest Id values occurred in periods of low density and not in those of high density, associated with seedling recruitment. Factors such as high seed production with low dispersal, massive germination in moit years and a comparatively high death rate of seedlings at sites more subject to flooding or more distant from the water table proved themselves able to promote this aggregate pattern and increase it during plant development.

  7. Combination of genetics and spatial modelling highlights the sensitivity of cod (Gadus morhua) population diversity in the North Sea to distributions of fishing

    DEFF Research Database (Denmark)

    Heath, Michael R.; Culling, Mark A.; Crozier, Walter W.;

    2014-01-01

    Conserving genetic diversity in animal populations is important for sustaining their ability to respond to environmental change. However, the “between-population” component of genetic diversity (biocomplexity) is threatened in many exploited populations, particularly marine fish, where harvest...... management regions may be larger than the spatial extent of genetically distinct subpopulations. Using single-nucleotide polymorphism data, we delineated the geographic limits of three population units of Atlantic cod (Gadus morhua) in northwest European waters. Two of the populations cohabit the North Sea......, and trawl survey data showed differing trends in their abundances. We developed a spatial model of these units to simulate population dynamics under spatial patterns of harvesting. Competition between units during the pelagic juvenile stages in the model led to suppression of the more localized...

  8. Personality-dependent dispersal: characterization, ontogeny and consequences for spatially structured populations

    OpenAIRE

    Cote, J; Clobert, J; Brodin, T; Fogarty, S.; Sih, A.

    2010-01-01

    Dispersal is one of the most fundamental components of ecology, and affects processes as diverse as population growth, metapopulation dynamics, gene flow and adaptation. Although the act of moving from one habitat to another entails major costs to the disperser, empirical and theoretical studies suggest that these costs can be reduced by having morphological, physiological or behavioural specializations for dispersal. A few recent studies on different systems showed that individuals exhibit p...

  9. Vegetation of Mangroves: Spatial and Temporal Pattern of its Dominant Populations in Futian National Nature Reserve

    Institute of Scientific and Technical Information of China (English)

    Li Zhenji; Zheng Wenjiao; Yang Zhiwei; Lin Yiming; Lin Peng

    2003-01-01

    The community characteristics of mangroves in the Futian Nature Reserve,Shenzhen, China are given based on surveying of 33 quadrats in 4 transects which stretch from the higher tidal zone to the lower tidal zone. The results show that there are 6 community types in this area: Kandelia cardel association, Avicennia marina association, A egiceras corniculatum association, Kardelia cardel + Aegiceras corniculatum association,Aegiceras corniculatum + Kandelia candel association and Acanthus ilicifolius association.Kandelia candel, Aegiceras corniculatum and Avicennia marina dominate the typical quadrats. Kandelia candel can be seen at almost all quadrats, Aegiceras corniculatum distributes mostly toward the estuary and the higher tidal zone, Avicennia marina distributes mostly toward the bay and the lower tidal zone, Bruguiera gymnorrhiza occasionally occurs toward the Estuary with one or several individuals, Acanthus ilicifolius was common toward the higher tidal zone, as an accompanying species, Derris trifoliata was common in many mature quadrats. Totally, 6 species of mangrove plants and 3 species of semi-mangrove plants appear in this research area. From the higher tidal zone to the lower tidal zone, the average diameter and basal area of mangrove trees increase gradually. According to the results, the Avicennia marina dominates in average diameter and basal area, and the Aegiceras corniculatum trees are on the contrary. From the transect 1 to the transect 4, the importance value of Avicennia marina, Bruguiera gymnorrhiza and Kandelia candel decreases, and Ae giceras corniculatum increases. In this area, the Kandelia candel population and Aegiceras corniculatum population are developing populations with many seedlings and saplings, but the Avicennia marina population is in a mature stage with few seedlings and not so many total individuals. According to this research, we suppose that Aegiceras corniculatum should be developed toward the estuary and the Avicennia

  10. The Spatial Structure of Young Stellar Clusters. II. Total Young Stellar Populations

    CERN Document Server

    Kuhn, Michael A; Feigelson, Eric D

    2015-01-01

    We investigate the intrinsic stellar populations (estimated total numbers of OB and pre-main-sequence stars down to 0.1 Mo) that are present in 17 massive star-forming regions (MSFRs) surveyed by the MYStIX project. The study is based on the catalog of >31,000 MYStIX Probable Complex Members with both disk-bearing and disk-free populations, compensating for extinction, nebulosity, and crowding effects. Correction for observational sensitivities is made using the X-ray Luminosity Function (XLF) and the near-infrared Initial Mass Function (IMF)--a correction that is often not made by infrared surveys of young stars. The resulting maps of the projected structure of the young stellar populations, in units of intrinsic stellar surface density, allow direct comparison between different regions. Several regions have multiple dense clumps, similar in size and density to the Orion Nebula Cluster. The highest projected density of ~34,000 stars/pc^2 is found in the core of the RCW38 cluster. Histograms of surface densit...

  11. Virgo cluster and field dwarf ellipticals in 3D: III. Spatially and temporally resolved stellar populations

    CERN Document Server

    Ryś, Agnieszka; Falcón-Barroso, Jesús; Vazdekis, Alexandre; Lisker, Thorsten; Peletier, Reynier; van de Ven, Glenn

    2015-01-01

    We present the stellar population analysis of a sample of 12 dwarf elliptical galaxies, observed with the SAURON integral field unit, using the full-spectrum fitting method. We show that star formation histories (SFHs) resolved into two populations can be recovered even within a limited wavelength range, provided that high S/N data is used. We confirm that dEs have had complex SFHs, with star formation extending to (more) recent epochs: for the majority of our galaxies star formation activity was either still strong a few ($\\lesssim$ 5) Gyr ago or they experienced a secondary burst of star formation roughly at that time. This latter possibility is in agreement with the proposed dE formation scenario where tidal harassment drives the gas remaining in their progenitors inwards and induces a star formation episode. For one of our field galaxies, ID0918, we find a correlation between its stellar population and kinematic properties, pointing to a possible merger origin of its kinematically-decoupled core. One of o...

  12. Spatial clustering of all-cause and HIV-related mortality in a rural South African population (2000-2006.

    Directory of Open Access Journals (Sweden)

    Elias Namosha

    Full Text Available BACKGROUND: Sub-Saharan Africa bears a disproportionate burden of HIV infection. Knowledge of the spatial distribution of HIV outcomes is vital so that appropriate public health interventions can be directed at locations most in need. In this regard, spatial clustering analysis of HIV-related mortality events has not been performed in a rural sub-Saharan African setting. METHODOLOGY AND RESULTS: Kulldorff's spatial scan statistic was used to identify HIV-related and all-cause mortality clusters (p<0.05 in a population-based demographic surveillance survey in rural KwaZulu Natal, South Africa (2000-2006. The analysis was split pre (2000-2003 and post (2004-2006 rollout of antiretroviral therapy, respectively. Between 2000-2006 a total of 86,175 resident individuals ≥15 years of age were under surveillance and 5,875 deaths were recorded (of which 2,938 were HIV-related over 343,060 person-years of observation (crude all-cause mortality rate 17.1/1000. During both time periods a cluster of high HIV-related (RR = 1.46/1.51, p = 0.001 and high all-cause mortality (RR = 1.35/1.38, p = 0.001 was identified in peri-urban communities near the National Road. A consistent low-risk cluster was detected in the urban township in both time periods (RR = 0.60/0.39, p = 0.003/0.005 and in the first time period (2000-2003 a large cluster of low HIV-related and all-cause mortality in a remote rural area was identified. CONCLUSIONS: HIV-related and all-cause mortality exhibit strong spatial clustering tendencies in this population. Highest HIV-related mortality and all-cause mortality occurred in the peri-urban communities along the National Road and was lowest in the urban township and remote rural communities. The geography of HIV-related mortality corresponded closely to the geography of HIV prevalence, with the notable exception of the urban township where high HIV-related mortality would have been expected on the basis of the high HIV

  13. Climate Risk and Vulnerability in the Caribbean and Gulf of Mexico Region: Interactions with Spatial Population and Land Cover Change

    Science.gov (United States)

    Chen, R. S.; Levy, M.; Baptista, S.; Adamo, S.

    2010-12-01

    Vulnerability to climate variability and change will depend on dynamic interactions between different aspects of climate, land-use change, and socioeconomic trends. Measurements and projections of these changes are difficult at the local scale but necessary for effective planning. New data sources and methods make it possible to assess land-use and socioeconomic changes that may affect future patterns of climate vulnerability. In this paper we report on new time series data sets that reveal trends in the spatial patterns of climate vulnerability in the Caribbean/Gulf of Mexico Region. Specifically, we examine spatial time series data for human population over the period 1990-2000, time series data on land use and land cover over 2000-2009, and infant mortality rates as a proxy for poverty for 2000-2008. We compare the spatial trends for these measures to the distribution of climate-related natural disaster risk hotspots (cyclones, floods, landslides, and droughts) in terms of frequency, mortality, and economic losses. We use these data to identify areas where climate vulnerability appears to be increasing and where it may be decreasing. Regions where trends and patterns are especially worrisome include coastal areas of Guatemala and Honduras.

  14. Carbon dynamics and ecosystem diversity of Amazonian peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Laehteenoja, O.

    2011-07-01

    The overall aim was to initiate peatland research in Amazonia, which has been referred to as 'one of the large white spots on the global peatland map'. Specifically, the study was to clarify how common peat accumulation is on Amazonian floodplains, and how extensive and thick peat deposits can be encountered. Secondly, the intention was to study how rapidly Amazonian peatlands sequester carbon, and how much carbon they store and thirdly, to gain some understanding of the diversity of peatland ecosystem types and of the processes forming these ecosystems

  15. Spatial ecology of the critically endangered Fijian crested iguana, Brachylophus vitiensis, in an extremely dense population: implications for conservation.

    Science.gov (United States)

    Morrison, Suzanne F; Biciloa, Pita; Harlow, Peter S; Keogh, J Scott

    2013-01-01

    The Critically Endangered Fijian crested iguana, Brachylophus vitiensis, occurs at extreme density at only one location, with estimates of >10,000 iguanas living on the 70 hectare island of Yadua Taba in Fiji. We conducted a mark and recapture study over two wet seasons, investigating the spatial ecology and intraspecific interactions of the strictly arboreal Fijian crested iguana. This species exhibits moderate male-biased sexual size dimorphism, which has been linked in other lizard species to territoriality, aggression and larger male home ranges. We found that male Fijian crested iguanas exhibit high injury levels, indicative of frequent aggressive interactions. We did not find support for larger home range size in adult males relative to adult females, however male and female residents were larger than roaming individuals. Males with established home ranges also had larger femoral pores relative to body size than roaming males. Home range areas were small in comparison to those of other iguana species, and we speculate that the extreme population density impacts considerably on the spatial ecology of this population. There was extensive home range overlap within and between sexes. Intersexual overlap was greater than intrasexual overlap for both sexes, and continuing male-female pairings were observed among residents. Our results suggest that the extreme population density necessitates extensive home range overlap even though the underlying predictors of territoriality, such as male biased sexual size dimorphism and high aggression levels, remain. Our findings should be factored in to conservation management efforts for this species, particularly in captive breeding and translocation programs. PMID:24019902

  16. Spatial ecology of the critically endangered Fijian crested iguana, Brachylophus vitiensis, in an extremely dense population: implications for conservation.

    Directory of Open Access Journals (Sweden)

    Suzanne F Morrison

    Full Text Available The Critically Endangered Fijian crested iguana, Brachylophus vitiensis, occurs at extreme density at only one location, with estimates of >10,000 iguanas living on the 70 hectare island of Yadua Taba in Fiji. We conducted a mark and recapture study over two wet seasons, investigating the spatial ecology and intraspecific interactions of the strictly arboreal Fijian crested iguana. This species exhibits moderate male-biased sexual size dimorphism, which has been linked in other lizard species to territoriality, aggression and larger male home ranges. We found that male Fijian crested iguanas exhibit high injury levels, indicative of frequent aggressive interactions. We did not find support for larger home range size in adult males relative to adult females, however male and female residents were larger than roaming individuals. Males with established home ranges also had larger femoral pores relative to body size than roaming males. Home range areas were small in comparison to those of other iguana species, and we speculate that the extreme population density impacts considerably on the spatial ecology of this population. There was extensive home range overlap within and between sexes. Intersexual overlap was greater than intrasexual overlap for both sexes, and continuing male-female pairings were observed among residents. Our results suggest that the extreme population density necessitates extensive home range overlap even though the underlying predictors of territoriality, such as male biased sexual size dimorphism and high aggression levels, remain. Our findings should be factored in to conservation management efforts for this species, particularly in captive breeding and translocation programs.

  17. Impacts of Landscape Context on Patterns of Wind Downfall Damage in a Fragmented Amazonian Landscape

    Science.gov (United States)

    Schwartz, N.; Uriarte, M.; DeFries, R. S.; Gutierrez-Velez, V. H.; Fernandes, K.; Pinedo-Vasquez, M.

    2015-12-01

    Wind is a major disturbance in the Amazon and has both short-term impacts and lasting legacies in tropical forests. Observed patterns of damage across landscapes result from differences in wind exposure and stand characteristics, such as tree stature, species traits, successional age, and fragmentation. Wind disturbance has important consequences for biomass dynamics in Amazonian forests, and understanding the spatial distribution and size of impacts is necessary to quantify the effects on carbon dynamics. In November 2013, a mesoscale convective system was observed over the study area in Ucayali, Peru, a highly human modified and fragmented forest landscape. We mapped downfall damage associated with the storm in order to ask: how does the severity of damage vary within forest patches, and across forest patches of different sizes and successional ages? We applied spectral mixture analysis to Landsat images from 2013 and 2014 to calculate the change in non-photosynthetic vegetation fraction after the storm, and combined it with C-band SAR data from the Sentinel-1 satellite to predict downfall damage measured in 30 field plots using random forest regression. We then applied this model to map damage in forests across the study area. Using a land cover classification developed in a previous study, we mapped secondary and mature forest, and compared the severity of damage in the two. We found that damage was on average higher in secondary forests, but patterns varied spatially. This study demonstrates the utility of using multiple sources of satellite data for mapping wind disturbance, and adds to our understanding of the sources of variation in wind-related damage. Ultimately, an improved ability to map wind impacts and a better understanding of their spatial patterns can contribute to better quantification of carbon dynamics in Amazonian landscapes.

  18. PMAS Optical Integral Field Spectroscopy of Luminous Infrared Galaxies. II.-- Spatially resolved stellar populations and excitation conditions

    CERN Document Server

    Alonso-Herrero, Almudena; Zaurin, Javier Rodriguez; Monreal-Ibero, Ana; Colina, Luis; Arribas, Santiago

    2010-01-01

    The general properties of luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) in the local universe are well known since large samples of these objects have been the subject of numerous spectroscopic works. There are, however, relatively few studies of large samples of LIRGs and ULIRGs using integral field spectroscopy (IFS). We analyze optical (3800-7200A) IFS data taken with the Potsdam Multi-Aperture Spectrophotometer (PMAS) of the central few kiloparsecs of 11 LIRGs. To study the stellar populations we fit the optical stellar continuum and the hydrogen recombination lines of selected regions. We analyze the excitation conditions of the gas using the spatially resolved properties of the brightest optical emission lines. The optical continua of the selected regions are well fitted with a combination of evolved (~0.7-10Gyr) and ionizing (1-20Myr) stellar populations. The latter is more obscured than the evolved population, and has visual extinctions in good agreement with those obtained from the ...

  19. Relationship between hierarchic - spatial differentiation of social structure and population size of municipalities in turkey: Evidence from the election case of local administration in 2004

    Directory of Open Access Journals (Sweden)

    Murat Çiftçi

    2011-07-01

    Full Text Available Turkey, whose population is young and dynamic, is a country where social change has a high acceleration. This circumstance has led to a spatial heterogeneity of social structure in the scale of campuses. Almost all the municipalities differ significantly from each other. In results of statistical applications, it was possible to conclude that there is a relationship between spatial differentiation of social structure indicators (PDI, PIDI and population sizes in municipalities. This relationship also supports that there was a differentiation of graded spatial social structure among municipalities in the Turkey of 2004. It is possible to make contact with this to the spatial differentiation that moves in parallel with population size and is in transition degree from a community to a society.

  20. Influence of drainage status on soil and water chemistry, litter decomposition and soil respiration in central Amazonian forests on sandy soils

    OpenAIRE

    Berton Zanchi, F.; M. J. Waterloo; A. J. Dolman; Groenendijk, M; Kruijt, B.

    2011-01-01

    Central Amazonian rainforest landscape supports a mosaic of tall terra firme rainforest and ecotone campinarana, riparian and campina forests, reflecting topography-induced variations in soil, nutrient and drainage conditions. Spatial and temporal variations in litter decomposition, soil and groundwater chemistry and soil CO2 respiration were studied in forests on sandy soils, whereas drought sensitivity of poorly-drained valley soils was investigated in an artificial drainage experiment. Sli...

  1. Spatial-temporal distribution of a Noctiluca scintillans population and its adaption to environmental conditions in northern South China Sea

    Directory of Open Access Journals (Sweden)

    Yu Wang

    2012-11-01

    Full Text Available Based on the data of a Noctiluca scintillans population in northern South China Sea (107°00′–119°00′E, 16°00′–24°00′N obtained in project “Integrated Investigation and Assessment of China Seas”(coded as 908 project in 2006 and 2008, we described the spatial distribution in wide geographical areas and seasonal variations of a Noctiluca scintillans population using GIS spatial analysis modeling and mapping techniques. The adaption of Noctiluca scintillans to temperature, salinity and nutrients were also discussed. The results showed that abundance of Noctiluca scintillans varied from 0.001×104 cells/m3 to 64.5×104 cells/m3, with an average of (0.56±3.29×104 cells/m3(n = 1,424. Average abundance varied by season, spring > autumn > winter > summer, with highest and lowest abundances of (1.28±4.24×104 cells/m3 (n = 356 and (0.19±0.95×104 cells/m3 (n = 356, respectively. The spatial distribution of Noctiluca scintillans generally decreased from alongshore to offshore areas, in a pattern of discontinuous patches. Abundance assemblage zones laid along the shores of eastern Leizhou peninsula, where it was also the peak abundance region in winter. The zones of low annunal abundance were primarily in the northern South China Sea. Dapeng Bay in eastern Guangdong Province and Pearl River Estuary were not abundance assemblage zones during summer and winter months. We found the shore of southeastern Hainan Island became high abundance zones during summer months. Compared with data of national integrated investigations completed in 1958 and 1959, Noctiluca scintillans abundance increased abruptly with an evident change of abundance assemblage zones. The seasonal variation was obvious. Average Noctiluca scintillans abundance was 27 times higher than recorded in 1959. Noctiluca scintillans populations in South China Sea required a much higher temperature than it did in East, Yellow and Bohai Seas in China. Salinity fluctuations were

  2. How the Dimension of Space Affects the Products of Pre-Biotic Evolution: The Spatial Population Dynamics of Structural Complexity and The Emergence of Membranes

    OpenAIRE

    Piantadosi, Steve T.; Crutchfield, James P.

    2010-01-01

    We show that autocatalytic networks of epsilon-machines and their population dynamics differ substantially between spatial (geographically distributed) and nonspatial (panmixia) populations. Generally, regions of spacetime-invariant autocatalytic networks---or domains---emerge in geographically distributed populations. These are separated by functional membranes of complementary epsilon-machines that actively translate between the domains and are responsible for their growth and stability. We...

  3. Amazonian Buriti oil: chemical characterization and antioxidant potential

    Directory of Open Access Journals (Sweden)

    Speranza, P.

    2016-06-01

    Full Text Available Buriti oil is an example of an Amazonian palm oil of economic importance. The local population uses this oil for the prevention and treatment of different diseases; however, there are few studies in the literature that evaluate its properties. In this study, detailed chemical and antioxidant properties of Buriti oil were determined. The predominant fatty acid was oleic acid (65.6% and the main triacylglycerol classes were tri-unsaturated (50.0% and di-unsaturated-mono-saturated (39.3% triacylglycerols. The positional distribution of the classes of fatty acids on the triacylglycerol backbone indicated a saturated and unsaturated fatty acid relationship similar in the three-triacylglycerol positions. All tocopherol isomers were present, with a total content of 2364.1 mg·kg−1. α-tocopherol constitutes 48% of the total tocopherol content, followed by γ- tocopherol (45%. Total phenolic (107.0 mg gallic acid equivalent·g−1 oil and β-carotene (781.6 mg·kg−1 were particularly high in this oil. The highest antioxidant activity against the free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH was obtained at an oil concentration of 50 mg·mL−1 (73.15%. The antioxidant activity evaluated by the Oxygen Radical Absorbance Capacity (ORAC was 95.3 μmol Trolox equivalent·g−1 oil. These results serve to present Buriti oil as an Amazonian resource for cosmetic, food and pharmaceuticals purposes.El aceite de Buriti es un ejemplo de aceite de palma amazónica de gran importancia económica. La población local utiliza este aceite para la prevención y el tratamiento de diferentes enfermedades; sin embargo, hay pocos estudios científicos que evalúen sus propiedades. En este estudio, se determinaron las propiedades antioxidantes del aceite de Buriti. El ácido graso predominante fue el oleico (65,6 % y las principales clases de triglicéridos fueron tri-insaturadas (50,0 % y Di-insaturados-mono-saturada (39,3 %. La distribución posicional de las

  4. Stochastic stability and the evolution of coordination in spatially structured populations.

    Science.gov (United States)

    Van Cleve, Jeremy; Lehmann, Laurent

    2013-11-01

    Animals can often coordinate their actions to achieve mutually beneficial outcomes. However, this can result in a social dilemma when uncertainty about the behavior of partners creates multiple fitness peaks. Strategies that minimize risk ("risk dominant") instead of maximizing reward ("payoff dominant") are favored in economic models when individuals learn behaviors that increase their payoffs. Specifically, such strategies are shown to be "stochastically stable" (a refinement of evolutionary stability). Here, we extend the notion of stochastic stability to biological models of continuous phenotypes at a mutation-selection-drift balance. This allows us to make a unique prediction for long-term evolution in games with multiple equilibria. We show how genetic relatedness due to limited dispersal and scaled to account for local competition can crucially affect the stochastically-stable outcome of coordination games. We find that positive relatedness (weak local competition) increases the chance the payoff dominant strategy is stochastically stable, even when it is not risk dominant. Conversely, negative relatedness (strong local competition) increases the chance that strategies evolve that are neither payoff nor risk dominant. Extending our results to large multiplayer coordination games we find that negative relatedness can create competition so extreme that the game effectively changes to a hawk-dove game and a stochastically stable polymorphism between the alternative strategies evolves. These results demonstrate the usefulness of stochastic stability in characterizing long-term evolution of continuous phenotypes: the outcomes of multiplayer games can be reduced to the generic equilibria of two-player games and the effect of spatial structure can be analyzed readily. PMID:23999503

  5. The spatial genetic differentiation of the legume pod borer, Maruca vitrata F. (Lepidoptera: Crambidae) populations in West Africa

    KAUST Repository

    Agunbiade, Tolulope A.

    2012-04-17

    The legume pod borer, Maruca vitrata, is an endemic insect pest that causes significant yield loss to the cowpea crop in West Africa. The application of population genetic tools is important in the management of insect pests but such data on M. vitrata is lacking. We applied a set of six microsatellite markers to assess the population structure of M. vitrata collected at five sites from Burkina Faso, Niger and Nigeria. Observed polymorphisms ranged from one (marker 3393) to eight (marker 32008) alleles per locus. Observed and expected heterozygosities ranged from 0.0 to 0.8 and 0.0 to 0.6, respectively. Three of the loci in samples from Nigeria and Burkina Faso deviated significantly from Hardy-Weinberg Equilibrium (HWE), whereas no loci deviated significantly in samples from Niger. Analysis of molecular variance (AMOVA) indicated that 67.3% level of the genetic variation was within individuals compared to 17.3% among populations. A global estimate of F ST=0.1 (ENA corrected F ST=0.1) was significant (Pa=0.05) and corroborated by pairwise F ST values that were significant among all possible comparisons. A significant correlation was predicted between genetic divergence and geographic distance between subpopulations (R2=0.6, P=0.04), and cluster analysis by the program STRUCTURE predicted that co-ancestry of genotypes were indicative of three distinct populations. The spatial genetic variance among M. vitrata in West Africa may be due to limited gene flow, south-north seasonal movement pattern or other reproductive barriers. This information is important for the cultural, chemical and biological control strategies for managing M. vitrata. Copyright © 2012 Cambridge University Press.

  6. Monitoring Tree Population Dynamics in Arid Zone Through Multiple Temporal Scales: Integration of Spatial Analysis, Change Detection and Field Long Term Monitoring

    Science.gov (United States)

    Isaacson, S.; Rachmilevitch, S.; Ephrath, J. E.; Maman, S.; Blumberg, D. G.

    2016-06-01

    High mortality rates and lack of recruitment in the acacia populations throughout the Negev Desert and the Arava rift valley of Israel have been reported in previous studies. However, it is difficult to determine whether these reports can be evidence to a significant decline trend of the trees populations. This is because of the slow dynamic processes of acaia tree populations and the lack of long term continuous monitoring data. We suggest a new data analysis technique that expands the time scope of the field long term monitoring of trees in arid environments. This will enables us to improve our understanding of the spatial and temporal changes of these populations. We implemented two different approaches in order to expand the time scope of the acacia population field survey: (1) individual based tree change detection using Corona satellite images and (2) spatial analysis of trees population, converting spatial data into temporal data. The next step was to integrate the results of the two analysis techniques (change detection and spatial analysis) with field monitoring. This technique can be implemented to other tree populations in arid environments to help assess the vegetation conditions and dynamics of those ecosystems.

  7. Fungal community assembly in the Amazonian Dark Earth

    NARCIS (Netherlands)

    Lucheta, A.R.; Souza Cannavan, F.S.; Roesch, L.; Tsai, S.M.; Kuramae, E.E.

    2016-01-01

    Here, we compare the fungal community composition and diversity in Amazonian Dark Earth (ADE) and the respective non-anthropogenic origin adjacent (ADJ) soils from four different sites in Brazilian Central Amazon using pyrosequencing of 18S ribosomal RNA (rRNA) gene. Fungal community composition in

  8. Local late Amazonian boulder breakdown and denudation rate on Mars

    NARCIS (Netherlands)

    de Haas, T.; Hauber, E.; Kleinhans, M.G.

    2013-01-01

    Inactive fan surfaces become smoother and develop desert pavement over time by weathering and erosion. We use this mechanism to estimate late Amazonian boulder breakdown and surface denudation rates on a young (∼1.25 Ma) (Schon et al., 2009) fan on Mars. This is done by comparing boulder size and su

  9. Spatial distribution of Galactic Wolf-Rayet stars and implications for the global population

    CERN Document Server

    Rosslowe, C K

    2014-01-01

    We construct revised near-infrared absolute magnitude calibrations for 126 Galactic Wolf-Rayet (WR) stars at known distances, based in part upon recent large scale spectroscopic surveys. Application to 246 WR stars located in the field, permits us to map their galactic distribution. As anticipated, WR stars generally lie in the thin disk (~40pc half width at half maximum) between galactocentric radii 3.5-10kpc, in accordance with other star formation tracers. We highlight 12 WR stars located at vertical distances of >300pc from the midplane. Analysis of the radial variation in WR subtypes exposes a ubiquitously higher N_{WC}/N_{WN} ratio than predicted by stellar evolutionary models accounting for stellar rotation. Models for non-rotating stars or accounting for close binary evolution are more consistent with observations. We consolidate information acquired about the known WR content of the Milky Way to build a simple model of the complete population. We derive observable quantities over a range of wavelengt...

  10. Defining temporal spatial patterns of mega city Istanbul to see the impacts of increasing population.

    Science.gov (United States)

    Sanli, Fusun Balik; Balcik, Filiz Bektas; Goksel, Cigdem

    2008-11-01

    Rapid land use change has taken place over the last few decades in Istanbul. As most of the metropolitan areas, Istanbul faces increasing problems connected to increasing population and urbanisation. In this study, temporal changes of Istanbul's land use/cover were defined using remotely sensed data and post classification change detection method. For the aim of the study, relevant information was derived from different dated Landsat Thematic Mapper (TM) satellite data by using Unsupervised Iterative Self-Organizing Data Analysis Technique (ISODATA) and results were examined with matrix analysis method. Ground truth data were used for the classification and accuracy assessment of the classification. Temporal changes of land use/cover classes of the mega city Istanbul between the years of 1992, 1997 and 2005 were examined for the management and decision making process. Landsat TM images were classified into six land use/cover types: forest-green area, bare land, water surface, road, urban area, and mining area. The results show that urban areas and road categories are increased greatly by 13,630 and 5,018ha, respectively, but forest-green areas decreased by 77,722ha over 13years between 1992 and 2005. The reason for the decrease in green areas is mainly because of development of unplanned urbanization and unavoidable migration. PMID:18157736

  11. Populism

    OpenAIRE

    Abts, Koenraad; van Kessel, Stijn

    2015-01-01

    Populism is a concept applied to a wide range of political movements and actors across the globe. There is, at the same time, considerable confusion about the attributes and manifestation of populism, as well as its impact on democracy. This contribution identifies the defining elements of the populist ideology and discusses the varieties in which populism manifests itself, for instance as a component of certain party families. We finally discuss various normative interpretations of populism,...

  12. Informing disease models with temporal and spatial contact structure among GPS-collared individuals in wild populations.

    Directory of Open Access Journals (Sweden)

    David M Williams

    Full Text Available Contacts between hosts are essential for transmission of many infectious agents. Understanding how contacts, and thus transmission rates, occur in space and time is critical to effectively responding to disease outbreaks in free-ranging animal populations. Contacts between animals in the wild are often difficult to observe or measure directly. Instead, one must infer contacts from metrics such as proximity in space and time. Our objective was to examine how contacts between white-tailed deer (Odocoileus virginianus vary in space and among seasons. We used GPS movement data from 71 deer in central New York State to quantify potential direct contacts between deer and indirect overlap in space use across time and space. Daily probabilities of direct contact decreased from winter (0.05-0.14, to low levels post-parturition through summer (0.00-0.02, and increased during the rut to winter levels. The cumulative distribution for the spatial structure of direct and indirect contact probabilities around a hypothetical point of occurrence increased rapidly with distance for deer pairs separated by 1,000 m-7,000 m. Ninety-five percent of the probabilities of direct contact occurred among deer pairs within 8,500 m of one another, and 99% within 10,900 m. Probabilities of indirect contact accumulated across greater spatial extents: 95% at 11,900 m and 99% at 49,000 m. Contacts were spatially consistent across seasons, indicating that although contact rates differ seasonally, they occur proportionally across similar landscape extents. Distributions of contact probabilities across space can inform management decisions for assessing risk and allocating resources in response.

  13. Spatial variation in osteon population density at the human femoral midshaft: histomorphometric adaptations to habitual load environment.

    Science.gov (United States)

    Gocha, Timothy P; Agnew, Amanda M

    2016-05-01

    Intracortical remodeling, and the osteons it produces, is one aspect of the bone microstructure that is influenced by and, in turn, can influence its mechanical properties. Previous research examining the spatial distribution of intracortical remodeling density across the femoral midshaft has been limited to either considering only small regions of the cortex or, when looking at the entirety of the cortex, considering only a single individual. This study examined the spatial distribution of all remodeling events (intact osteons, fragmentary osteons, and resorptive bays) across the entirety of the femoral midshaft in a sample of 30 modern cadaveric donors. The sample consisted of 15 males and 15 females, aged 21-97 years at time of death. Using geographic information systems software, the femoral cortex was subdivided radially into thirds and circumferentially into octants, and the spatial location of all remodeling events was marked. Density maps and calculation of osteon population density in cortical regions of interest revealed that remodeling density is typically highest in the periosteal third of the bone, particularly in the lateral and anterolateral regions of the cortex. Due to modeling drift, this area of the midshaft femur has some of the youngest primary tissue, which consequently reveals that the lateral and anterolateral regions of the femoral midshaft have higher remodeling rates than elsewhere in the cortex. This is likely the result of tension/shear forces and/or greater strain magnitudes acting upon the anterolateral femur, which results in a greater amount of microdamage in need of repair than is seen in the medial and posterior regions of the femoral midshaft, which are more subject to compressive forces and/or lesser strain magnitudes. PMID:26708961

  14. Seasonal variation in attention and spatial performance in a wild population of the African striped mouse (Rhabdomys pumilio).

    Science.gov (United States)

    Maille, Audrey; Pillay, Neville; Schradin, Carsten

    2015-11-01

    Cognitive flexibility describes the reversible changes of cognition in response to environmental changes. Although various environmental factors such as temperature, photoperiod and rainfall change seasonally, seasonal variation in cognitive performance has been reported in merely a few birds and mammals. We assessed whether cognitive performance in a wild population of African striped mice Rhabdomys pumilio, from the Succulent Karoo semidesert of South Africa, differed between summer and winter. In order to measure cognitive performance, striped mice were trapped in the field, tested under laboratory conditions at our research station and returned to the field within 5 h. We measured attention and spatial memory using the standardized orientation response test and the Barnes maze test. Males tested during summer oriented faster toward a predator-stimulus but made more errors and took longer to locate a shelter than males tested during winter. In contrast, females' performance did not differ between the two seasons. We discuss how the faster orientation in males during winter might be the consequence of lower temperatures and/or prolonged food restriction. We suggest that the enhancement of spatial performance during winter might be due to a greater motivation for future dispersal in male striped mice, as spring represents the breeding season. PMID:26139344

  15. Spatial correlations of population and ecological factors with distribution of visceral leishmaniasis cases in southwestern Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Amin Ghatee

    2013-08-01

    Full Text Available Background & objectives: Leishmaniasis as a dynamic disease may be markedly influenced by demographic and ecological factors. A geospatial information system study was developed to determine the distribution of visceral leishmaniasis (VL cases in relation to population, climatic and environmental factors in Fars province, southwest of Iran. Methods: The dwelling addresses of 217 VL patients were obtained from hospital files. A hazard map produced by unifying buffers (5 km around nomads travel routes (NTR was developed to survey the effect of close proximity to NTR on the distribution of VL. Mean annual rainfall (MAR, mean annual temperature (MAT, four months temperature mean (T4, elevation, slope and landcover were climatic and environmental factors that have been analysed. Finally, data of dwelling foci were extracted from maps and analysed using logistic regression models. Results: Close proximity to NTR was the most important factor influenced on the disease distribution. Climatic factors were in second rank. Among them, temperature especially T4 is the most effective variable and rainfall was also shown to be another effective climatic agent. Most cases of VL were reported from temperate and semiarid areas in western and central regions while arid condition was a confined factor. The environmental factor of landcovers including urban, dry farm and thin forest regions was revealed as the third rank effective factor. Altitude importance was only shown when its effect was studied independently from other factors. Interpretation & conclusion: These findings present the distribution of VL in Fars province is influenced by combination of ecological and nomads demographical variables although closeness to NTR and nomads role in distribution and continuance of kala-azar are the most important factors.

  16. Accounting for regional background and population size in the detection of spatial clusters and outliers using geostatistical filtering and spatial neutral models: the case of lung cancer in Long Island, New York

    Directory of Open Access Journals (Sweden)

    Goovaerts Pierre

    2004-07-01

    Full Text Available Abstract Background Complete Spatial Randomness (CSR is the null hypothesis employed by many statistical tests for spatial pattern, such as local cluster or boundary analysis. CSR is however not a relevant null hypothesis for highly complex and organized systems such as those encountered in the environmental and health sciences in which underlying spatial pattern is present. This paper presents a geostatistical approach to filter the noise caused by spatially varying population size and to generate spatially correlated neutral models that account for regional background obtained by geostatistical smoothing of observed mortality rates. These neutral models were used in conjunction with the local Moran statistics to identify spatial clusters and outliers in the geographical distribution of male and female lung cancer in Nassau, Queens, and Suffolk counties, New York, USA. Results We developed a typology of neutral models that progressively relaxes the assumptions of null hypotheses, allowing for the presence of spatial autocorrelation, non-uniform risk, and incorporation of spatially heterogeneous population sizes. Incorporation of spatial autocorrelation led to fewer significant ZIP codes than found in previous studies, confirming earlier claims that CSR can lead to over-identification of the number of significant spatial clusters or outliers. Accounting for population size through geostatistical filtering increased the size of clusters while removing most of the spatial outliers. Integration of regional background into the neutral models yielded substantially different spatial clusters and outliers, leading to the identification of ZIP codes where SMR values significantly depart from their regional background. Conclusion The approach presented in this paper enables researchers to assess geographic relationships using appropriate null hypotheses that account for the background variation extant in real-world systems. In particular, this new

  17. Spatial and stage-structured population model of the American crocodile for comparison of comprehensive Everglades Restoration Plan (CERP) alternatives

    Science.gov (United States)

    Green, Timothy W.; Slone, Daniel H.; Swain, Eric D.; Cherkiss, Michael S.; Lohmann, Melinda; Mazzotti, Frank J.; Rice, Kenneth G.

    2010-01-01

    As part of the U.S. Geological Survey Priority Ecosystems Science (PES) initiative to provide the ecological science required during Everglades restoration, we have integrated current regional hydrologic models with American crocodile (Crocodylus acutus) research and monitoring data to create a model that assesses the potential impact of Comprehensive Everglades Restoration Plan (CERP) efforts on the American crocodile. A list of indicators was created by the Restoration Coordination and Verification (RECOVER) component of CERP to help determine the success of interim restoration goals. The American crocodile was established as an indicator of the ecological condition of mangrove estuaries due to its reliance upon estuarine environments characterized by low salinity and adequate freshwater inflow. To gain a better understanding of the potential impact of CERP restoration efforts on the American crocodile, a spatially explicit crocodile population model has been created that has the ability to simulate the response of crocodiles to various management strategies for the South Florida ecosystem. The crocodile model uses output from the Tides and Inflows in the Mangroves of the Everglades (TIME) model, an application of the Flow and Transport in a Linked Overland/Aquifer Density Dependent System (FTLOADDS) simulator. TIME has the capability to link to the South Florida Water Management Model (SFWMM), which is the primary regional tool used to assess CERP restoration scenarios. A crocodile habitat suitability index and spatial parameter maps that reflect salinity, water depth, habitat, and nesting locations are used as driving functions to construct crocodile finite rate of increase maps under different management scenarios. Local stage-structured models are integrated with a spatial landscape grid to display crocodile movement behavior in response to changing environmental conditions. Restoration efforts are expected to affect salinity levels throughout the habitat of

  18. Regional Hydro-Climatic Changes due to Three Decades of Amazonian Deforestation

    Science.gov (United States)

    Khanna, J.; Medvigy, D.; Fueglistaler, S.; Walko, R. L.

    2015-12-01

    A gamut of studies exist which posit that small scale conversion of forests to urban, pasture or cropland can trigger an increase in regional cloudiness and rain. Several of these studies, pertaining to early stages of Amazonian deforestation, attribute this phenomenon to heightened thermal triggering resulting from small-scale (a few kilometers) patchy deforestation. But it is not clear if this phenomenon can be extrapolated to contemporary (tens of kilometers) or future scales of deforestation. Here, we have carried out the first long-time period study of the effects of changing scales of Amazonian deforestation on regional cloudiness and precipitation using satellite observations made by GOES and TRMM. We have analyzed observations made over the deforested areas in the Brazilian state of Rondonia. We find a shift in the regional hydroclimatic regime over the three decades of deforestation - from spatially uniform cloudiness to dominant cloudiness in the downwind half of the deforested domain. This result is not consistent with a thermal triggering mechanism because thermal triggering would only explain the uniform cloud cover observed during the early stages of deforestation. To further investigate the mechanism, we have also carried out numerical simulations. We found that surface roughness gradients caused by contemporary large scales of deforestation can explain this observed transition. This transition is climatologically important for this region because it affects the observed spatial distribution of precipitation, which has become dominant in the downwind half of the deforested domain in contemporary times. The new mechanism identified here should be accounted for in planning for future land-use change in the Amazon.

  19. Step selection techniques uncover the environmental predictors of space use patterns in flocks of Amazonian birds.

    Science.gov (United States)

    Potts, Jonathan R; Mokross, Karl; Stouffer, Philip C; Lewis, Mark A

    2014-12-01

    Understanding the behavioral decisions behind animal movement and space use patterns is a key challenge for behavioral ecology. Tools to quantify these patterns from movement and animal-habitat interactions are vital for transforming ecology into a predictive science. This is particularly important in environments undergoing rapid anthropogenic changes, such as the Amazon rainforest, where animals face novel landscapes. Insectivorous bird flocks are key elements of avian biodiversity in the Amazonian ecosystem. Therefore, disentangling and quantifying the drivers behind their movement and space use patterns is of great importance for Amazonian conservation. We use a step selection function (SSF) approach to uncover environmental drivers behind movement choices. This is used to construct a mechanistic model, from which we derive predicted utilization distributions (home ranges) of flocks. We show that movement decisions are significantly influenced by canopy height and topography, but depletion and renewal of resources do not appear to affect movement significantly. We quantify the magnitude of these effects and demonstrate that they are helpful for understanding various heterogeneous aspects of space use. We compare our results to recent analytic derivations of space use, demonstrating that the analytic approximation is only accurate when assuming that there is no persistence in the animals' movement. Our model can be translated into other environments or hypothetical scenarios, such as those given by proposed future anthropogenic actions, to make predictions of spatial patterns in bird flocks. Furthermore, our approach is quite general, so could potentially be used to understand the drivers of movement and spatial patterns for a wide variety of animal communities. PMID:25558353

  20. Large-scale heterogeneity of Amazonian phenology revealed from 26-year long AVHRR/NDVI time-series

    International Nuclear Information System (INIS)

    Depiction of phenological cycles in tropical forests is critical for an understanding of seasonal patterns in carbon and water fluxes as well as the responses of vegetation to climate variations. However, the detection of clear spatially explicit phenological patterns across Amazonia has proven difficult using data from the Moderate Resolution Imaging Spectroradiometer (MODIS). In this work, we propose an alternative approach based on a 26-year time-series of the normalized difference vegetation index (NDVI) from the Advanced Very High Resolution Radiometer (AVHRR) to identify regions with homogeneous phenological cycles in Amazonia. Specifically, we aim to use a pattern recognition technique, based on temporal signal processing concepts, to map Amazonian phenoregions and to compare the identified patterns with field-derived information. Our automated method recognized 26 phenoregions with unique intra-annual seasonality. This result highlights the fact that known vegetation types in Amazonia are not only structurally different but also phenologically distinct. Flushing of new leaves observed in the field is, in most cases, associated to a continuous increase in NDVI. The peak in leaf production is normally observed from the beginning to the middle of the wet season in 66% of the field sites analyzed. The phenoregion map presented in this work gives a new perspective on the dynamics of Amazonian canopies. It is clear that the phenology across Amazonia is more variable than previously detected using remote sensing data. An understanding of the implications of this spatial heterogeneity on the seasonality of Amazonian forest processes is a crucial step towards accurately quantifying the role of tropical forests within global biogeochemical cycles. (letter)

  1. Human health risk assessment with spatial analysis: Study of a population chronically exposed to arsenic through drinking water from Argentina

    International Nuclear Information System (INIS)

    Arsenic (As) is a ubiquitous element widely distributed in the environment. This metalloid has proven carcinogenic action in man. The aim of this work was to assess the health risk related to As exposure through drinking water in an Argentinean population, applying spatial analytical techniques in addition to conventional approaches. The study involved 650 inhabitants from Chaco and Santiago del Estero provinces. Arsenic in drinking water (Asw) and urine (UAs) was measured by hydride generation atomic absorption spectrophotometry. Average daily dose (ADD), hazard quotient (HQ), and carcinogenic risk (CR) were estimated, geo-referenced and integrated with demographical data by a health composite index (HI) applying geographic information system (GIS) analysis. Asw covered a wide range of concentration: from non-detectable (ND) to 2000 μg/L. More than 90% of the population was exposed to As, with UAs levels above the intervention level of 100 μg/g creatinine. GIS analysis described an expected level of exposure lower than the observed, indicating possible additional source/s of exposure to inorganic arsenic. In 68% of the locations, the population had a HQ greater than 1, and the CR ranged between 5·10−5 and 2,1·10−2. An environmental exposure area through ADD geo-referencing defined a baseline scenario for space-time risk assessment. The time of residence, the demographic density and the potential health considered outcomes helped characterize the health risk in the region. The geospatial analysis contributed to delimitate and analyze the change tendencies of risk in the region, broadening the scopes of the results for a decision-making process. - Highlights: • Risk assessment (RA) to As using deterministic procedures • Integration of RA through deterministic procedures with GIS tools • Analysis of the time-space behavior of the risk area • Analysis of As effect outcomes through HI • Broaden the scopes of deterministic approaches

  2. Human health risk assessment with spatial analysis: Study of a population chronically exposed to arsenic through drinking water from Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Navoni, J.A., E-mail: jnavoni@ffyb.uba.ar [Cátedra de Toxicología y Química Legal, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, C1113AAD Ciudad Autónoma de Buenos Aires (Argentina); De Pietri, D., E-mail: depietrid@hotmail.com [Dirección Nacional de Determinantes de la Salud e Investigación, Ministerio de Salud de la Nación, Av. 9 de Julio 1925, C1073ABA Ciudad Autónoma de Buenos Aires (Argentina); Olmos, V. [Cátedra de Toxicología y Química Legal, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, C1113AAD Ciudad Autónoma de Buenos Aires (Argentina); Gimenez, C. [Cátedra Química Analítica I, Universidad Nacional del Chaco Austral. Cmte., Fernández 755 (3700), Pres. Roque Sáenz Peña, Chaco (Argentina); Bovi Mitre, G. [Grupo INQA (Investigación Química Aplicada) Facultad de Ciencias Agrarias, Universidad Nacional de Jujuy, Alberdi 47, piso 1, San Salvador de Jujuy, Jujuy CP 4600 (Argentina); and others

    2014-11-15

    Arsenic (As) is a ubiquitous element widely distributed in the environment. This metalloid has proven carcinogenic action in man. The aim of this work was to assess the health risk related to As exposure through drinking water in an Argentinean population, applying spatial analytical techniques in addition to conventional approaches. The study involved 650 inhabitants from Chaco and Santiago del Estero provinces. Arsenic in drinking water (Asw) and urine (UAs) was measured by hydride generation atomic absorption spectrophotometry. Average daily dose (ADD), hazard quotient (HQ), and carcinogenic risk (CR) were estimated, geo-referenced and integrated with demographical data by a health composite index (HI) applying geographic information system (GIS) analysis. Asw covered a wide range of concentration: from non-detectable (ND) to 2000 μg/L. More than 90% of the population was exposed to As, with UAs levels above the intervention level of 100 μg/g creatinine. GIS analysis described an expected level of exposure lower than the observed, indicating possible additional source/s of exposure to inorganic arsenic. In 68% of the locations, the population had a HQ greater than 1, and the CR ranged between 5·10{sup −5} and 2,1·10{sup −2}. An environmental exposure area through ADD geo-referencing defined a baseline scenario for space-time risk assessment. The time of residence, the demographic density and the potential health considered outcomes helped characterize the health risk in the region. The geospatial analysis contributed to delimitate and analyze the change tendencies of risk in the region, broadening the scopes of the results for a decision-making process. - Highlights: • Risk assessment (RA) to As using deterministic procedures • Integration of RA through deterministic procedures with GIS tools • Analysis of the time-space behavior of the risk area • Analysis of As effect outcomes through HI • Broaden the scopes of deterministic approaches.

  3. Spatial Variation in the Population Structure and Reproductive Biology of Rimicaris hybisae (Caridea: Alvinocarididae) at Hydrothermal Vents on the Mid-Cayman Spreading Centre

    OpenAIRE

    Verity Nye; Copley, Jonathan T.; Tyler, Paul A.

    2013-01-01

    The dynamics and microdistribution of faunal assemblages at hydrothermal vents often reflect the fine-scale spatial and temporal heterogeneity of the vent environment. This study examined the reproductive development and population structure of the caridean shrimp Rimicaris hybisae at the Beebe and Von Damm Vent Fields (Mid-Cayman Spreading Centre, Caribbean) using spatially discrete samples collected in January 2012. Rimicaris hybisae is gonochoric and exhibits iteroparous reproduction. Oocy...

  4. The association of genetic markers and malaria infection in the Brazilian Western Amazonian region

    Directory of Open Access Journals (Sweden)

    B Beiguelman

    2003-06-01

    Full Text Available Almost all individuals (182 belonging to an Amazonian riverine population (Portuchuelo, RO, Brazil were investigated for ascertaining data on epidemiological aspects of malaria. Thirteen genetic blood polymorphisms were investigated (ABO, MNSs, Rh, Kell, and Duffy systems, haptoglobins, hemoglobins, and the enzymes glucose-6-phosphate dehydrogenase, glyoxalase, phosphoglucomutase, carbonic anhydrase, red cell acid phosphatase, and esterase D. The results indicated that the Duffy system is associated with susceptibility to malaria, as observed in other endemic areas. Moreover, suggestions also arose indicating that the EsD and Rh loci may be significantly associated with resistance to malaria. If statistical type II errors and sample stratification could be ruled out, hypotheses on the existence of a causal mechanism or an unknown closely linked locus involved in susceptibility to malaria infection may explain the present findings.

  5. Spatial analysis of Lobesia botrana (Lepidoptera: Tortricidae) male population in a mediterranean agricultural landscape in central Italy.

    Science.gov (United States)

    Sciarretta, A; Zinni, A; Mazzocchetti, A; Trematerra, P

    2008-04-01

    The results obtained from the spatial analysis of pheromone-baited trap catch data of Lobesia botrana (Denis and Schiffermüller) males are reported. The research was undertaken in the Abruzzo region of central Italy. In the study area, vineyards (of Vitis vinifera L.) are the predominant cultivation, surrounded by hedgerows and small woodlots, and interspersed with cereal crops and olive groves. The main purpose of the study was to investigate the spatio-temporal dynamics of L. botrana, inside and outside vineyards, and to evaluate the effect of the landscape elements on pest distribution. A trend orientation over the experimental area was observed along the direction from northwest to southeast. Correlograms fitted using a spherical model showed in all cases an aggregated distribution and an estimated range having a mean of 174 m in 2005 and 116 m in 2006. Contour maps highlighted that spatial distribution of L. botrana was not limited to vineyards, but its presence is high particularly inside olive groves. The adult distribution on the experimental area changed during the season: hot spots of flight I were positioned inside olive groves; during flights II and III, they were concentrated in vineyards. L. botrana males were also captured in uncultivated fields, but never in high densities. Our results showed that a large proportion of the adult population of L. botrana inhabits areas outside those usually targeted by pest management programs. Thus, in Mediterranean agro-ecosystems, it is highly recommended to consider the whole landscape, with particular attention to olive crops. PMID:18419910

  6. Modelling herbivore population dynamics in the Amboseli National Park, Kenya : application of spatial aggregation of variables to derive a master model

    OpenAIRE

    Mose, V. N.; Tri, Nguyen-Huu; Auger, Pierre; Western, D.

    2012-01-01

    The recent expansion of human activities such as agriculture has continuously threatened to block wildlife migration corridors that connect Amboseli National Park (Kenya) to surrounding ecosystems. We study the impact of blocked corridors on herbivore populations using a spatial mathematical model that describes the movements and population dynamics of selected species (zebra, wildebeest and Grant's gazelle) based on resource availability. Aggregation methods are used to reduce the complexity...

  7. Spatial distribution of Brucella antibodies with reference to indigenous cattle populations among contrasting agro-ecological zones of Uganda.

    Science.gov (United States)

    Kabi, Fredrick; Muwanika, Vincent; Masembe, Charles

    2015-09-01

    Indigenous cattle populations exhibit various degrees of agro-ecological fitness and provide desirable opportunities for investments to improve sustainable production for better rural small-scale farmers' incomes globally. However, they could be a source of infection to their attendants and other susceptible livestock if their brucellosis status remains unknown. This study investigated the spatial distribution of Brucella antibodies among indigenous cattle populations in Uganda. Sera from a total of 925 indigenous cattle (410 Ankole Bos taurus indicus, 50 Nganda and 465 East African Shorthorn Zebu (EASZ) - B. indicus) obtained randomly from 209 herds spread throughout Uganda were sequentially analysed for Brucella antibodies using the indirect (I) and competitive (C) enzyme linked Immuno-sorbent assays (ELISA). Recent incidences of abortion within the previous 12 months and routine hygienic practices during parturition were explored for public health risks. Brucella antibodies occurred in approximately 8.64% (80/925) and 28.70% (95% CI: 22.52, 34.89) of the sampled individual cattle and herds, respectively. Findings have shown that Ankole and EASZ cattle had similar seroprevalences. Indigenous cattle from the different study agro-ecological zones (AEZs) exhibited varying seroprevalences ranging from approximately 1.78% (95% CI: 0, 5.29) to 19.67% (95% CI: 8.99, 30.35) in the Lake Victoria Crescent (LVC) and North Eastern Drylands (NED) respectively. Significantly higher odds for Brucella antibodies occurred in the NED (OR: 3.40, 95% CI: 1.34, 8.57, p=0.01) inhabited by EASZ cattle compared to the KP (reference category) AEZ. Recent incidences of abortions within the previous 12 months were significantly (ppractices and mass vaccination. PMID:26100405

  8. Local-scale spatial variation in diversity of social wasps in an Amazonian rain forest in Caxiuanã, Pará, Brazil (Hymenoptera, Vespidae, Polistinae) Variação na diversidade de vespas sociais em escala local numa floresta pluvial amazônica em Caxiuanã, Pará, Brasil (Hymenoptera, Vespidae, Polistinae)

    OpenAIRE

    Orlando Tobias Silveira; Suzanna de Sousa Silva; Jorge Luis Gavina Pereira; Ingrid da Silva Tavares

    2012-01-01

    Polistine wasps are important in Neotropical ecosystems due to their ubiquity and diversity. Inventories have not adequately considered spatial attributes of collected specimens. Spatial data on biodiversity are important for study and mitigation of anthropogenic impacts over natural ecosystems and for protecting species. We described and analyzed local-scale spatial patterns of collecting records of wasp species, as well as spatial variation of diversity descriptors in a 2500-hectare area of...

  9. Spatial Distribution of the Population in Shandong Province at Multi-Scales%山东省人口空间分布格局的多尺度分析

    Institute of Scientific and Technical Information of China (English)

    王静; 杨小唤; 石瑞香

    2012-01-01

    人口空间分布具有一定的尺度依赖性,从不同尺度上对人口空间分布格局进行分析,可以更确切、真实地揭示人口的空间分布规律,为制定区域发展规划、灾害评价、环境保护等提供科学依据。本文以山东省为研究区,运用空间自相关方法和统计相关分析方法,比较市级、县级、1 km三个尺度上人口分布的空间自相关性及其与环境—经济因子的统计相关性,试图探讨不同尺度下人口的空间分布模式及影响(指示)因素,从不同尺度揭示人口的空间分布格局特征。结果表明:①从不同尺度对人口的空间分布格局进行分析,可以得到从宏观到微观不同详细程度的信息。从市级尺度分析,可以得到山东省整体的人口空间分布特征;从县级尺度分析,可以得到山东省各市内部的人口空间分布特征;从1 km尺度分析,可以得到山东省各县内部的人口空间分布特征。②不同尺度上,人口的空间分布格局特征不同。市级和县级尺度上,人口分布受环境—经济因子的影响表现出与一些因子显著相关,而受空间集聚的作用较小;1 km尺度上,人口分布与环境—经济因子的相关性较小,而主要受空间集聚的作用,在县内部,人口往往集中分布于某一区域,呈现出典型的集聚分布模式。%The spatial distribution of population is essential for both environmental and socio-economic researches.Traditional studies on the spatial distribution of population are mostly based on single scale analysis and ignores scale dependence of population distribution.Analysing the spatial distribution of population at different scales is beneficial to more exactly reveal the spatial distribution law of population.This paper analyzed and compared the spatial autocorrelation of population density using spatial autocorrelation method and statistical correlations between population density and environment-economic factors

  10. Gale Crater: An Amazonian Impact Crater Lake at the Plateau/Plain Boundary

    Science.gov (United States)

    Cabrol, N. A.; Grin, E. A.

    1998-01-01

    sedimentary material that can originate both from drainage of the regional subsurface aquifer, and/or from surface flood. The central deposit shows three main levels: (a) the current crater floor (north of Gale), (b) an ancient level about 200 rn higher (south of Gale), and (c) the massive terraced deposits. A crater statistics on the 15,400 kM2 area of the crater floor and deposit [3,41 gave: 259+/-112.4 craters, most of them partly embayed in the sedimentary deposit, and all inferior to 5-km diameter. For superimposed crater population only, the result is 194+/-112. The deduced relative ages ranges from Early to Middle Amazonian. The population of craters are comparable for the three levels, implying that the last sedimentation/erosion episode on Gale was recent and affected the whole crater. The streamlined morphology of the border of the deposit, the layering, the channels, and the terraces are compatible with a significant fluvio-lacustrine history of the site. Multiple levels may suggest different episodes, but the common statistical age of the three levels shows that the last episode involved the whole crater. The origin of the lake water in Gale may have varied in time. Three major contributions have been proposed: (a) the drainage of the regional underground aquifer by Gale crater over an area of 110-km radius around the crater which would have provided approximately 1,600 cubic km of water, (b), surface drainage entering Gale by the south and north rims. In the south, a 250-km long system originates in the cratered uplands in a Noachian crater material plain (Nc), and crosses Hesperian and Amazonian crater material plains (AHc) northward [1]. Several fluvial systems originate in the Aeolis Mensae, east of Gale. They may had two functions in time: to recharge, the underground aquifer in the region of Gale, and to supply surface water in the crater by overspilling the northern rim, and (c) surface floods that originated from the rising of the water level in the

  11. Isozyme characterization of Capsicum accessions from the Amazonian Colombian collection

    Directory of Open Access Journals (Sweden)

    Lorena Quintero Barrera

    2007-02-01

    Full Text Available Two hundred and sixty-one accessions of the genus Capsicum were obtained from the Colombian Amazonian germplasm bank at Amazonian Institute of Scientific Research (Sinchi and were evaluated with five polymorphic enzymatic systems, including esterase (EST, peroxidase (PRX, 6-phosphogluconate dehydrogenase (6-PGDH, aspartate amino transferase (GOT, and malic enzyme (ME. Using a cluster analysis (UPGMA the genetic variability of these accessions were characterized. Grouping of the species C. baccatum and C. pubescens were observed, while the species C. annuum, C. chinense and C. frutescens did not group independently, a result that has been previously reported in isoenzyme analyses of this genus. Several accessions were deemed of particular interest for future ecological and evolutive studies. Key words: Colombia, Capsicum, germplasm bank, isoenzymes, peppers.

  12. Local late Amazonian boulder breakdown and denudation rate on Mars

    Science.gov (United States)

    Haas, Tjalling; Hauber, Ernst; Kleinhans, Maarten G.

    2013-07-01

    Inactive fan surfaces become smoother and develop desert pavement over time by weathering and erosion. We use this mechanism to estimate late Amazonian boulder breakdown and surface denudation rates on a young (˜1.25 Ma) (Schon et al., 2009) fan on Mars. This is done by comparing boulder size and surface relief between lobes of different ages. The boulder breakdown rate is 3.5 m/Myr, surface smoothing (denudation) rate is approximated as 0.89 m/Myr. These rates exceed previous estimates for the Amazonian by orders of magnitude. We attribute this to locality, high initial smoothing rates after morphological activity and obliquity and eccentricity-driven variation in the availability of (metastable) liquid water, which acts as a catalyst for weathering during these periods. The results have major implications for process interpretation of Martian landforms, as they imply that typical small-scale morphology may be subdued within <1 Myr.

  13. Fish complementarity is associated to forests in Amazonian streams

    Directory of Open Access Journals (Sweden)

    Carolina Rodrigues Bordignon

    2015-09-01

    Full Text Available The functional structure of communities is commonly measured by the variability in functional traits, which may demonstrate complementarity or redundancy patterns. In this study, we tested the influence of environmental variables on the functional structure of fish assemblages in Amazonian streams within a deforestation gradient. We calculated six ecomorphological traits related to habitat use from each fish species, and used them to calculate the net relatedness index (NRI and the nearest taxon index (NTI. The set of species that used the habitat differently (complementary or overdispersed assemblages occurred in sites with a greater proportion of forests. The set of species that used the habitat in a similar way (redundant or clustered assemblages occurred in sites with a greater proportion of grasses in the stream banks. Therefore, the deforestation of entire watersheds, which has occurred in many Amazonian regions, may be a central factor for the functional homogenization of fish fauna.

  14. Spatially Resolved Stellar Populations Of Nearby Post-Starburst Galaxies In SDSS-IV MaNGA

    Science.gov (United States)

    Liu, Charles; Betances, Ashley; Bonilla, Alaina Marie; Gonzalez, Andrea; Migliore, Christina; Goddard, Daniel; Masters, Karen; SDSS-IV MaNGA Team

    2016-01-01

    We have selected five galaxies in the Mapping Nearby Galaxies at APO (MaNGA) project of the latest generation of the Sloan Digital Sky Survey (SDSS-IV) identified as post-starburst (E+A) systems, in the transition between "blue cloud" and "red sequence" galaxies. We measure the equivalent widths of the Balmer series, D4000 break, and metal lines across each galaxy, and produce maps of the stellar age, stellar mass, and metallicities of each galaxy using FIREFLY, a full spectral analysis code. We have found that the measured properties of the galaxies overall generally matches well with single-aperture SDSS spectra from which the original post-starburst identifications were made. The variation in the spatial distributions of the stellar populations, in particular the A-stars, give us insight into the details of the transitional E+A quenching phase. This work was supported by the Alfred P. Sloan Foundation via the SDSS-IV Faculty and Student Team (FAST) initiative, ARC Agreement No. SSP483 to the CUNY College of Staten Island.

  15. Alluvial plain dynamics in the southern Amazonian foreland basin

    OpenAIRE

    Lombardo, U

    2015-01-01

    Alluvial plains are formed with sediments that rivers deposit on the adjacent flood-basin, mainly through crevasse splays and avulsions. These result from a combination of processes, some of which push the river towards the crevasse threshold, while others act as triggers. Based on the floodplain sedimentation patterns of large rivers in the southern Amazonian foreland basin, it has been suggested that alluvial plain sediment accumulation ...

  16. Fungal Community Assembly in the Amazonian Dark Earth

    OpenAIRE

    Lucheta, A.R.; Souza Cannavan, F.S.; Roesch, L.; Tsai, S.M.; Kuramae, E.E.

    2015-01-01

    Here, we compare the fungal community composition and diversity in Amazonian Dark Earth (ADE) and the respective non-anthropogenic origin adjacent (ADJ) soils from four different sites in Brazilian Central Amazon using pyrosequencing of 18S ribosomal RNA (rRNA) gene. Fungal community composition in ADE soils were more similar to each other than their ADJ soils, except for only one site. Phosphorus and aluminum saturation were the main soil chemical factors contributing to ADE and ADJ fungal c...

  17. The impact of Amazonian deforestation on Amazon basin rainfall

    OpenAIRE

    Spracklen, DV; Garcia-Carreras, L.

    2015-01-01

    We completed a meta-analysis of regional and global climate model simulations (n=96) of the impact of Amazonian deforestation on Amazon basin rainfall. Across all simulations, mean (±1σ) change in annual mean Amazon basin rainfall was -12±11%. Variability in simulated rainfall was not explained by differences in model resolution or surface parameters. Across all simulations we find a negative linear relationship between rainfall and deforestation extent, although individual studies often simu...

  18. Poor Prospects for Avian Biodiversity in Amazonian Oil Palm

    OpenAIRE

    Lees, Alexander C.; Moura, Nárgila G.; Arlete Silva de Almeida; Ima C G Vieira

    2015-01-01

    Expansion of oil palm plantations across the humid tropics has precipitated massive loss of tropical forest habitats and their associated speciose biotas. Oil palm plantation monocultures have been identified as an emerging threat to Amazonian biodiversity, but there are no quantitative studies exploring the impact of these plantations on the biome's biota. Understanding these impacts is extremely important given the rapid projected expansion of oil palm cultivation in the basin. Here we inve...

  19. Joy within tranquility: Amazonian Urarina styles of happiness

    OpenAIRE

    Walker, Harry

    2015-01-01

    Enjoyment in life among Amazonian Urarina is examined through the lens of two contrastive concepts of happiness. The first, “tranquility,” is a relatively long-term, relational condition implying emotional spontaneity and a flexible, freely chosen work routine that allows for a merging of action and awareness. It epitomizes a broader concern with the development of an individual “style of life,” where attitudes, manners, and actions come into alignment. The second concept, “joy...

  20. Planning a red squirrel conservation area: using a spatially explicit population dynamics model to predict the impact of felling and forest design plans

    NARCIS (Netherlands)

    Lurz, P.W.W.; Geddes, N.; Lloyd, A.J.; Shirley, M.D.E.; Rushton, B.; Burlton, B.

    2003-01-01

    This paper describes the use of a spatially explicit population model (SEPM) to investigate the effects of different forest management strategies on a red squirrel conservation area. The study was based in woodland managed by Forest Enterprise, which manages 75 000 ha of woodlands in Northumberland,

  1. Food Plants Eaten by Amazonian Manatees (Trichechus inunguis, Mammalia : Sirenia

    Directory of Open Access Journals (Sweden)

    Colares Ioni G.

    2002-01-01

    Full Text Available To determine the feeding habits of the Amazonian manatee Trichechus inunguis in some Central Amazonian rivers and lakes, we compared plant epidermis found in the stomach contents and/or faeces of animals with a reference collection of plants present in the studied areas. Twenty five samples from digestive tracts of animals found dead and 25 faeces samples found floating were analyzed. From these samples, 24 aquatic macrophytes were identified. The Gramineae family was identified in 96% of the samples, Paspalum repens and Echinochloa polystachya being the most abundant in the samples. The second most frequent family was the Pontederiaceae primarily Eichhornia crassipes. During the high water period, the animals showed a more selective diet (eight identified species. In the low water period, when food was more scarce, the animals showed a larger diversity of species in their diet (21 species of plants. Differences in the diet among the two studied areas reflected the physiographics characteristics of the region. Amazonian manatees fed mostly on emergent plants.

  2. How domain growth is implemented determines the long-term behavior of a cell population through its effect on spatial correlations

    Science.gov (United States)

    Ross, Robert J. H.; Baker, R. E.; Yates, C. A.

    2016-07-01

    Domain growth plays an important role in many biological systems, and so the inclusion of domain growth in models of these biological systems is important to understanding how these systems function. In this work we present methods to include the effects of domain growth on the evolution of spatial correlations in a continuum approximation of a lattice-based model of cell motility and proliferation. We show that, depending on the way in which domain growth is implemented, different steady-state densities are predicted for an agent population. Furthermore, we demonstrate that the way in which domain growth is implemented can result in the evolution of the agent density depending on the size of the domain. Continuum approximations that ignore spatial correlations cannot capture these behaviors, while those that account for spatial correlations do. These results will be of interest to researchers in developmental biology, as they suggest that the nature of domain growth can determine the characteristics of cell populations.

  3. A moving target—incorporating knowledge of the spatial ecology of fish into the assessment and management of freshwater fish populations

    Science.gov (United States)

    Cooke, Steven J.; Martins, Eduardo G; Struthers, Daniel P; Gutowsky, Lee F G; Powers, Michael H.; Doka, Susan E; Dettmers, John M.; Crook, David A; Lucas, Martyn C.; Holbrook, Christopher; Krueger, Charles C.

    2016-01-01

    Freshwater fish move vertically and horizontally through the aquatic landscape for a variety of reasons, such as to find and exploit patchy resources or to locate essential habitats (e.g., for spawning). Inherent challenges exist with the assessment of fish populations because they are moving targets. We submit that quantifying and describing the spatial ecology of fish and their habitat is an important component of freshwater fishery assessment and management. With a growing number of tools available for studying the spatial ecology of fishes (e.g., telemetry, population genetics, hydroacoustics, otolith microchemistry, stable isotope analysis), new knowledge can now be generated and incorporated into biological assessment and fishery management. For example, knowing when, where, and how to deploy assessment gears is essential to inform, refine, or calibrate assessment protocols. Such information is also useful for quantifying or avoiding bycatch of imperiled species. Knowledge of habitat connectivity and usage can identify critically important migration corridors and habitats and can be used to improve our understanding of variables that influence spatial structuring of fish populations. Similarly, demographic processes are partly driven by the behavior of fish and mediated by environmental drivers. Information on these processes is critical to the development and application of realistic population dynamics models. Collectively, biological assessment, when informed by knowledge of spatial ecology, can provide managers with the ability to understand how and when fish and their habitats may be exposed to different threats. Naturally, this knowledge helps to better evaluate or develop strategies to protect the long-term viability of fishery production. Failure to understand the spatial ecology of fishes and to incorporate spatiotemporal data can bias population assessments and forecasts and potentially lead to ineffective or counterproductive management actions.

  4. A moving target--incorporating knowledge of the spatial ecology of fish into the assessment and management of freshwater fish populations.

    Science.gov (United States)

    Cooke, Steven J; Martins, Eduardo G; Struthers, Daniel P; Gutowsky, Lee F G; Power, Michael; Doka, Susan E; Dettmers, John M; Crook, David A; Lucas, Martyn C; Holbrook, Christopher M; Krueger, Charles C

    2016-04-01

    Freshwater fish move vertically and horizontally through the aquatic landscape for a variety of reasons, such as to find and exploit patchy resources or to locate essential habitats (e.g., for spawning). Inherent challenges exist with the assessment of fish populations because they are moving targets. We submit that quantifying and describing the spatial ecology of fish and their habitat is an important component of freshwater fishery assessment and management. With a growing number of tools available for studying the spatial ecology of fishes (e.g., telemetry, population genetics, hydroacoustics, otolith microchemistry, stable isotope analysis), new knowledge can now be generated and incorporated into biological assessment and fishery management. For example, knowing when, where, and how to deploy assessment gears is essential to inform, refine, or calibrate assessment protocols. Such information is also useful for quantifying or avoiding bycatch of imperiled species. Knowledge of habitat connectivity and usage can identify critically important migration corridors and habitats and can be used to improve our understanding of variables that influence spatial structuring of fish populations. Similarly, demographic processes are partly driven by the behavior of fish and mediated by environmental drivers. Information on these processes is critical to the development and application of realistic population dynamics models. Collectively, biological assessment, when informed by knowledge of spatial ecology, can provide managers with the ability to understand how and when fish and their habitats may be exposed to different threats. Naturally, this knowledge helps to better evaluate or develop strategies to protect the long-term viability of fishery production. Failure to understand the spatial ecology of fishes and to incorporate spatiotemporal data can bias population assessments and forecasts and potentially lead to ineffective or counterproductive management actions

  5. A Molecular Survey of the Diversity of Microbial Communities in Different Amazonian Agricultural Model Systems

    Directory of Open Access Journals (Sweden)

    Acácio A. Navarrete

    2010-05-01

    Full Text Available The processes of land conversion and agricultural intensification are a significant cause of biodiversity loss, with consequent negative effects both on the environment and the sustainability of food production.The anthrosols associated with pre-Colombian settlements in the Amazonian region are examples of how anthropogenic activities may sustain the native populations against harsh tropical environments for human establishment, even without a previous intentionality of anthropic soil formation. In a case study (Model I—“Slash-and-Burn” the community structures detected by automated ribosomal intergenic spacer analysis (ARISA revealed that soil archaeal, bacterial and fungal communities are heterogeneous and each capable of responding differently to environmental characteristics. ARISA data evidenced considerable difference in structure existing between microbial communities in forest and agricultural soils. In a second study (Model II—“Anthropogenic Soil”, the bacterial community structures revealed by terminal restriction fragment length polymorphism (T-RFLP differed among an Amazonian Dark Earth (ADE, black carbon (BC and its adjacent non-anthropogenic oxisoil. The bacterial 16S rRNA gene (OTU richness estimated by pyrosequencing was higher in ADE than BC. The most abundant bacterial phyla in ADE soils and BC were Proteobacteria—24% ADE, 15% BC; Acidobacteria—10% ADE, 21% BC; Actinobacteria—7% ADE, 12% BC; Verrucomicrobia, 8% ADE; 9% BC; Firmicutes—3% ADE, 8% BC. Overall, unclassified bacteria corresponded to 36% ADE, and 26% BC. Regardless of current land uses, our data suggest that soil microbial community structures may be strongly influenced by the historical soil management and that anthrosols in Amazonia, of anthropogenic origins, in addition to their capacity of enhancing crop yields, may also improve microbial diversity, with the support of the black carbon, which may sustain a particular and unique habitat for the

  6. Spatial variation in the population structure and reproductive biology of Rimicaris hybisae (Caridea: Alvinocarididae at hydrothermal vents on the Mid-Cayman Spreading Centre.

    Directory of Open Access Journals (Sweden)

    Verity Nye

    Full Text Available The dynamics and microdistribution of faunal assemblages at hydrothermal vents often reflect the fine-scale spatial and temporal heterogeneity of the vent environment. This study examined the reproductive development and population structure of the caridean shrimp Rimicaris hybisae at the Beebe and Von Damm Vent Fields (Mid-Cayman Spreading Centre, Caribbean using spatially discrete samples collected in January 2012. Rimicaris hybisae is gonochoric and exhibits iteroparous reproduction. Oocyte size-frequency distributions (21-823 µm feret diameters varied significantly among samples. Embryo development was asynchronous among females, which may result in asynchronous larval release for the populations. Specimens of R. hybisae from the Von Damm Vent Field (2294 m were significantly larger than specimens from the Beebe Vent Field. Brooding females at Von Damm exhibited greater size-specific fecundity, possibly as a consequence of a non-linear relationship between fecundity and body size that was consistent across both vent fields. Samples collected from several locations at the Beebe Vent Field (4944-4972 m revealed spatial variability in the sex ratios, population structure, size, and development of oocytes and embryos of this mobile species. Samples from the Von Damm Vent Field and sample J2-613-24 from Beebe Woods exhibited the highest frequencies of ovigerous females and significantly female-biased sex ratios. Environmental variables within shrimp aggregations may influence the distribution of ovigerous females, resulting in a spatially heterogeneous pattern of reproductive development in R. hybisae, as found in other vent taxa.

  7. Spatial-temporal trends and risk of suicide in Central Brazil: an ecological study contrasting indigenous and non-indigenous populations

    Directory of Open Access Journals (Sweden)

    Jesem D. Orellana

    2016-01-01

    Full Text Available Objective: To examine spatial-temporal distribution and risk of suicide, as well as trends in suicide mortality rates, in the indigenous and non-indigenous population of the state of Mato Grosso do Sul, Brazil. Methods: Data were obtained from the Information Department of the Brazilian Unified Health System. Deaths recorded as voluntary self-inflicted injuries (ICD-10 codes X60.0 to X84.9 were considered suicide. Suicide rates were estimated and adjusted by age in the population > 9 years of age. Kernel analysis was used to assess the spatial distribution of suicide cases, while trend analysis was carried out using a non-parametric test (Mann-Kendall. Results: The suicide risk among the indigenous population was 8.1 (95%CI 7.2-9.0 times higher than in the non-indigenous population. For indigenous residents in the 15-24 age group, the risk was 18.5 (95%CI 17.5-19.6 times higher than in the non-indigenous population. The majority of indigenous cases were concentrated in a few villages in reservation areas, mainly occupied by Guarani-Kaiowá and Guarani-Ñandeva groups. Rate patterns remained stable over time in both groups. Conclusion: Suicide is a serious public health problem in Mato Grosso do Sul, and has had an alarming and disproportionate impact on the indigenous population for more than a decade.

  8. A new multidimensional population health indicator for policy makers: absolute level, inequality and spatial clustering - an empirical application using global sub-national infant mortality data

    Directory of Open Access Journals (Sweden)

    Benn K.D. Sartorius

    2014-11-01

    Full Text Available The need for a multidimensional measure of population health that accounts for its distribution remains a central problem to guide the allocation of limited resources. Absolute proxy measures, like the infant mortality rate (IMR, are limi- ted because they ignore inequality and spatial clustering. We propose a novel, three-part, multidimensional mortality indi- cator that can be used as the first step to differentiate interventions in a region or country. The three-part indicator (MortalityABC index combines absolute mortality rate, the Theil Index to calculate mortality inequality and the Getis-Ord G statistic to determine the degree of spatial clustering. The analysis utilises global sub-national IMR data to empirically illu- strate the proposed indicator. The three-part indicator is mapped globally to display regional/country variation and further highlight its potential application. Developing countries (e.g. in sub-Saharan Africa display high levels of absolute mortality as well as variable mortality inequality with evidence of spatial clustering within certain sub-national units (“hotspots”. Although greater inequality is observed outside developed regions, high mortality inequality and spatial clustering are com- mon in both developed and developing countries. Significant positive correlation was observed between the degree of spatial clustering and absolute mortality. The proposed multidimensional indicator should prove useful for spatial allocation of healthcare resources within a country, because it can prompt a wide range of policy options and prioritise high-risk areas. The new indicator demonstrates the inadequacy of IMR as a single measure of population health, and it can also be adapted to lower administrative levels within a country and other population health measures.

  9. Long and short-term spatial processes analysis of an acacia tree population using a single aerial photograph with near infra-red band

    Science.gov (United States)

    Isaacson, Sivan; Blumberg, Dan G.; Rachmilevitch, Shimon; Ephrath, Jhonathan E.

    2014-05-01

    Hyper-arid zones are characterized by highly sparse vegetation cover. Monitoring vegetation dynamics in hyper-arid zones is important because any reduction in the vegetation cover in these areas can lead to a considerable reduction in the carrying capacity of the ecological system. Remote sensing expands the spatial and temporal database and is thus a powerful tool for long-term monitoring in arid zones, where access is limited and long-term ground data are rarely available. The main goal of this research was to study both the long-term and short-term spatial processes affecting the acacia population, by using information from a single, three bands color infrared (CIR) aerial photograph (green, red and near infrared). CIR images enable us to obtain information about photosynthetically active biomass by using vegetation indices such as NDVI. A map of individual acacia trees that was extracted from a CIR aerial photograph of Wadi Ktora allowed us to examine the distribution pattern of the trees size and foliage health status (NDVI). Tree size distribution was used as an indicator of long-term (decades) geo-hydrologic spatial processes effecting the acacia population. The tree health status distribution was used as an indicator for short-term (months to a few years) geo-hydrologic spatial processes, such as the paths of recent flashfloods events. Comparison of the tree size distribution and NDVI values distribution enabled us to differentiate between long-term and short-term processes that brought the population to its present state. The spatial analysis revealed that both the tree size and NDVI distribution patterns were significantly clustered, suggesting that the processes responsible for tree size and tree health status do have a spatial expression. Furthermore, each of the attributes has a different distribution and unique clustering location. We suggest that the lack of spatial correlation between tree size and health status is a result of spatial

  10. Fire effects on the composition of a bird community in an Amazonian savanna (Brazil).

    Science.gov (United States)

    Cintra, R; Sanaiotti, T M

    2005-11-01

    The effects of fire on the composition of a bird community were investigated in an Amazonian savanna near Alter-do-Chão, Pará (Brazil). Mist-net captures and visual counts were used to assess species richness and bird abundance pre- and post-fire in an approximately 20 ha area. Visual counts along transects were used to survey birds in an approximately 2000 ha area in a nearby area. Results using the same method of ordination analysis (multidimensional scaling) showed significant effects of fire in the 20 ha and 2000 ha areas and strongly suggest direct effects on bird community composition. However, the effects were different at different spatial scales and/or in different years, indicating that the effects of fire vary spatially and/or temporally. Bird community composition pre-fire was significantly different from that found post-fire. Using multiple regression analysis it was found that the numbers of burned and unburned trees were not significantly related to either bird species richness or bird abundance. Two months after the fire, neither bird species richness nor bird abundance was significantly related to the number of flowering trees (Lafoensia pacari) or fruiting trees (Byrsonima crassifolia). Since fire is an annual event in Alter-do-Chão and is becoming frequent in the entire Amazon, bird community composition in affected areas could be constantly changing in time and space. PMID:16532193

  11. A spatial analysis of population dynamics and climate change in Africa: potential vulnerability hot spots emerge where precipitation declines and demographic pressures coincide

    Science.gov (United States)

    López-Carr, David; Pricope, Narcisa G.; Aukema, Juliann E.; Jankowska, Marta M.; Funk, Christopher C.; Husak, Gregory J.; Michaelsen, Joel C.

    2014-01-01

    We present an integrative measure of exposure and sensitivity components of vulnerability to climatic and demographic change for the African continent in order to identify “hot spots” of high potential population vulnerability. Getis-Ord Gi* spatial clustering analyses reveal statistically significant locations of spatio-temporal precipitation decline coinciding with high population density and increase. Statistically significant areas are evident, particularly across central, southern, and eastern Africa. The highly populated Lake Victoria basin emerges as a particularly salient hot spot. People located in the regions highlighted in this analysis suffer exceptionally high exposure to negative climate change impacts (as populations increase on lands with decreasing rainfall). Results may help inform further hot spot mapping and related research on demographic vulnerabilities to climate change. Results may also inform more suitable geographical targeting of policy interventions across the continent.

  12. Spatial organisation of badgers (Meles meles in a medium-density population in Luxembourg

    Directory of Open Access Journals (Sweden)

    Alain C Frantz

    2010-08-01

    Full Text Available

    Abstract
    Any hypothesis aiming to explain the social organisation of Eurasian badgers Meles meles has to consider its wide inter-population variability. We used radiotracking techniques to investigate the spatial organisation and the pattern of space-use by badger in Luxembourg, where badger density can be considered moderate compared to most of Europe.
    Eight badgers belonging to five social groups were caught and radio-collared. The size of individual home ranges, as assesses by 100% minimum convex polygons in spring-summer 2002 and 2003, varied from 42.5 ha to 171.8 ha. Core areas corresponded to the 50-70% kernel isopleths and covered an average of 10.1% of individual home ranges. The home ranges of badgers caught at the same sett overlapped largely (average 83.3%, whilst the overlap between neighbouring ranges did not exceed 13.8%. Altogether six boundary latrines were found at the intersection of group ranges. Overall, the spatial system of the Luxembourg badgers is quite flexible, with the boundaries of some group ranges remaining constant over the years, while others may expand or contract.
    Riassunto
    Organizzazione spaziale del tasso (Meles meles in una popolazione a media densità del Lussemburgo.
    Qualsiasi ipotesi che voglia spiegare l’organizzazione sociale del tasso Meles meles, deve tener conto della sua ampia variabilità tra le popolazioni.
    Tramite la radiotelemetria e il monitoraggio delle latrine, la struttura territoriale e l’uso dello spazio da parte del tasso sono stati analizzati in una popolazione del Lussemburgo, dove la densità della specie può essere considerata intermedia rispetto ai valori noti per il resto dell’Europa.
    Sono stati marcati con radio-collari otto tassi, appartenenti a cinque diversi gruppi sociali. Le dimensioni delle aree vitali, stimate con il minimo poligono convesso al 100

  13. A trans-Amazonian screening of mtDNA reveals deep intraspecific divergence in forest birds and suggests a vast underestimation of species diversity.

    Directory of Open Access Journals (Sweden)

    Borja Milá

    Full Text Available The Amazonian avifauna remains severely understudied relative to that of the temperate zone, and its species richness is thought to be underestimated by current taxonomy. Recent molecular systematic studies using mtDNA sequence reveal that traditionally accepted species-level taxa often conceal genetically divergent subspecific lineages found to represent new species upon close taxonomic scrutiny, suggesting that intraspecific mtDNA variation could be useful in species discovery. Surveys of mtDNA variation in Holarctic species have revealed patterns of variation that are largely congruent with species boundaries. However, little information exists on intraspecific divergence in most Amazonian species. Here we screen intraspecific mtDNA genetic variation in 41 Amazonian forest understory species belonging to 36 genera and 17 families in 6 orders, using 758 individual samples from Ecuador and French Guiana. For 13 of these species, we also analyzed trans-Andean populations from the Ecuadorian Chocó. A consistent pattern of deep intraspecific divergence among trans-Amazonian haplogroups was found for 33 of the 41 taxa, and genetic differentiation and genetic diversity among them was highly variable, suggesting a complex range of evolutionary histories. Mean sequence divergence within families was the same as that found in North American birds (13%, yet mean intraspecific divergence in Neotropical species was an order of magnitude larger (2.13% vs. 0.23%, with mean distance between intraspecific lineages reaching 3.56%. We found no clear relationship between genetic distances and differentiation in plumage color. Our results identify numerous genetically and phenotypically divergent lineages which may result in new species-level designations upon closer taxonomic scrutiny and thorough sampling, although lineages in the tropical region could be older than those in the temperate zone without necessarily representing separate species. In

  14. A trans-Amazonian screening of mtDNA reveals deep intraspecific divergence in forest birds and suggests a vast underestimation of species diversity.

    Science.gov (United States)

    Milá, Borja; Tavares, Erika S; Muñoz Saldaña, Alberto; Karubian, Jordan; Smith, Thomas B; Baker, Allan J

    2012-01-01

    The Amazonian avifauna remains severely understudied relative to that of the temperate zone, and its species richness is thought to be underestimated by current taxonomy. Recent molecular systematic studies using mtDNA sequence reveal that traditionally accepted species-level taxa often conceal genetically divergent subspecific lineages found to represent new species upon close taxonomic scrutiny, suggesting that intraspecific mtDNA variation could be useful in species discovery. Surveys of mtDNA variation in Holarctic species have revealed patterns of variation that are largely congruent with species boundaries. However, little information exists on intraspecific divergence in most Amazonian species. Here we screen intraspecific mtDNA genetic variation in 41 Amazonian forest understory species belonging to 36 genera and 17 families in 6 orders, using 758 individual samples from Ecuador and French Guiana. For 13 of these species, we also analyzed trans-Andean populations from the Ecuadorian Chocó. A consistent pattern of deep intraspecific divergence among trans-Amazonian haplogroups was found for 33 of the 41 taxa, and genetic differentiation and genetic diversity among them was highly variable, suggesting a complex range of evolutionary histories. Mean sequence divergence within families was the same as that found in North American birds (13%), yet mean intraspecific divergence in Neotropical species was an order of magnitude larger (2.13% vs. 0.23%), with mean distance between intraspecific lineages reaching 3.56%. We found no clear relationship between genetic distances and differentiation in plumage color. Our results identify numerous genetically and phenotypically divergent lineages which may result in new species-level designations upon closer taxonomic scrutiny and thorough sampling, although lineages in the tropical region could be older than those in the temperate zone without necessarily representing separate species. In-depth phylogeographic surveys

  15. Mosquito-Producing Containers, Spatial Distribution, and Relationship between Aedes aegypti Population Indices on the Southern Boundary of its Distribution in South America (Salto, Uruguay)

    Science.gov (United States)

    Basso, César; Caffera, Ruben M.; García da Rosa, Elsa; Lairihoy, Rosario; González, Cristina; Norbis, Walter; Roche, Ingrid

    2012-01-01

    A study was conducted in the city of Salto, Uruguay, to identify mosquito-producing containers, the spatial distribution of mosquitoes and the relationship between the different population indices of Aedes aegypti. On each of 312 premises visited, water-filled containers and immature Ae. aegypti mosquitoes were identified. The containers were counted and classified into six categories. Pupae per person and Stegomyia indices were calculated. Pupae per person were represented spatially. The number of each type of container and number of mosquitoes in each were analyzed and compared, and their spatial distribution was analyzed. No significant differences in the number of the different types of containers with mosquitoes or in the number of mosquitoes in each were found. The distribution of the containers with mosquito was random and the distribution of mosquitoes by type of container was aggregated or highly aggregated. PMID:23128295

  16. Alluvial plain dynamics in the southern Amazonian foreland basin

    Directory of Open Access Journals (Sweden)

    U. Lombardo

    2015-10-01

    Full Text Available Alluvial plains are formed with sediments that rivers deposit on the adjacent flood-basin, mainly through crevasse splays and avulsions. These result from a combination of processes, some of which push the river towards the crevasse threshold, while others act as triggers. Based on the floodplain sedimentation patterns of large rivers in the southern Amazonian foreland basin, it has been suggested that alluvial plain sediment accumulation is primarily the result of river crevasse splays triggered by above normal precipitation events due to La Niña. However, more than 90 % of the Amazonian river network is made of small rivers and it is unknown whether small river floodplain sedimentation is influenced by the ENSO cycle as well. Using Landsat images from 1984 to 2014, here I analyse the behaviour of all the twelve tributaries of the Río Mamoré with a catchment in the Andes. I show that these are very active rivers and that the frequency of crevasses is not linked to ENSO activity. I found that most of the sediments eroded from the Andes by the tributaries of the Mamoré are deposited in the alluvial plains, before reaching the parent river. The mid- to late Holocene paleo-channels of these rivers are located tens of kilometres further away from the Andes than the modern crevasses. I conclude that the frequency of crevasses is controlled by intrabasinal processes that act on a year to decade time scale, while the average location of the crevasses is controlled by climatic or neo-tectonic events that act on a millennial scale. Finally, I discuss the implications of river dynamics on rural livelihoods and biodiversity in the Llanos de Moxos, a seasonally flooded savannah covering most of the southern Amazonian foreland basin and the world's largest RAMSAR site.

  17. Alluvial plain dynamics in the southern Amazonian foreland basin

    Science.gov (United States)

    Lombardo, Umberto

    2016-05-01

    Alluvial plains are formed with sediments that rivers deposit on the adjacent flood-basin, mainly through crevasse splays and avulsions. These result from a combination of processes, some of which push the river towards the crevasse threshold, while others act as triggers. Based on the floodplain sedimentation patterns of large rivers in the southern Amazonian foreland basin, it has been suggested that alluvial plain sediment accumulation is primarily the result of river crevasse splays and sheet sands triggered by above-normal precipitation events due to La Niña. However, more than 90 % of the Amazonian river network is made of small rivers and it is unknown whether small river floodplain sedimentation is influenced by the ENSO cycle as well. Using Landsat images from 1984 to 2014, here I analyse the behaviour of all 12 tributaries of the Río Mamoré with a catchment in the Andes. I show that these are very active rivers and that the frequency of crevasses is not linked to ENSO activity. The data suggest that most of the sediments eroded from the Andes by the tributaries of the Mamoré are deposited in the alluvial plains, before reaching the parent river. The mid-to-late Holocene paleo-channels of these rivers are located tens of kilometres further away from the Andes than the modern crevasses. I conclude that the frequency of crevasses is controlled by intrabasinal processes that act on a yearly to decadal timescale, while the average location of the crevasses is controlled by climatic or neo-tectonic events that act on a millennial scale. Finally, I discuss the implications of river dynamics on rural livelihoods and biodiversity in the Llanos de Moxos, a seasonally flooded savannah covering most of the southern Amazonian foreland basin and the world's largest RAMSAR site.

  18. Environmental change and the carbon balance of Amazonian forests.

    Science.gov (United States)

    Aragão, Luiz E O C; Poulter, Benjamin; Barlow, Jos B; Anderson, Liana O; Malhi, Yadvinder; Saatchi, Sassan; Phillips, Oliver L; Gloor, Emanuel

    2014-11-01

    Extreme climatic events and land-use change are known to influence strongly the current carbon cycle of Amazonia, and have the potential to cause significant global climate impacts. This review intends to evaluate the effects of both climate and anthropogenic perturbations on the carbon balance of the Brazilian Amazon and to understand how they interact with each other. By analysing the outputs of the Intergovernmental Panel for Climate Change (IPCC) Assessment Report 4 (AR4) model ensemble, we demonstrate that Amazonian temperatures and water stress are both likely to increase over the 21st Century. Curbing deforestation in the Brazilian Amazon by 62% in 2010 relative to the 1990s mean decreased the Brazilian Amazon's deforestation contribution to global land use carbon emissions from 17% in the 1990s and early 2000s to 9% by 2010. Carbon sources in Amazonia are likely to be dominated by climatic impacts allied with forest fires (48.3% relative contribution) during extreme droughts. The current net carbon sink (net biome productivity, NBP) of +0.16 (ranging from +0.11 to +0.21) Pg C year(-1) in the Brazilian Amazon, equivalent to 13.3% of global carbon emissions from land-use change for 2008, can be negated or reversed during drought years [NBP = -0.06 (-0.31 to +0.01) Pg C year(-1) ]. Therefore, reducing forest fires, in addition to reducing deforestation, would be an important measure for minimizing future emissions. Conversely, doubling the current area of secondary forests and avoiding additional removal of primary forests would help the Amazonian gross forest sink to offset approximately 42% of global land-use change emissions. We conclude that a few strategic environmental policy measures are likely to strengthen the Amazonian net carbon sink with global implications. Moreover, these actions could increase the resilience of the net carbon sink to future increases in drought frequency. PMID:25324039

  19. Spatial structure of food contamination with 137Cs and estimation of long-term internal dose loads on population of Belarus

    International Nuclear Information System (INIS)

    An analysis of 53,207 records of 137Cs contents in 83 types of food products obtained in 1993 in Belarus was carried out. Internal exposure by eight selected food components has been estimated. To map the non-uniformly distributed data, different types of geostatical approaches are used. The results of spatial analysis of long term internal dose loads on populations under high radiation risk could be used in decision making. (author)

  20. Food preference of the amazonian manatee in captivity

    OpenAIRE

    Elton Pinto Colares; Ioni Gonçalves Colares

    2011-01-01

    Studies on one endangered species´ feeding contribute to the more complex knowledge about its ecology, as also its preservation and/or management. By this means, aiming to obtain one better development and food supply for the animals kept in captivity in the Instituto Nacional de Pesquisa da Amazônia, one experiment was conducted to verify their food preferences. Aiming to observe the Amazonian manatee´s feeding behavior, eight animals were used kept inside one pool with 28,26 m2 and 1,0 m de...

  1. A management-oriented framework for selecting metrics used to assess habitat- and path-specific quality in spatially structured populations

    Science.gov (United States)

    Sam Nicol; Ruscena Wiederholt; Diffendorfer, James E.; Brady Mattsson; Thogmartin, Wayne E.; Semmens, Darius J.; Laura Lopez-Hoffman; Ryan Norris

    2016-01-01

    Mobile species with complex spatial dynamics can be difficult to manage because their population distributions vary across space and time, and because the consequences of managing particular habitats are uncertain when evaluated at the level of the entire population. Metrics to assess the importance of habitats and pathways connecting habitats in a network are necessary to guide a variety of management decisions. Given the many metrics developed for spatially structured models, it can be challenging to select the most appropriate one for a particular decision. To guide the management of spatially structured populations, we define three classes of metrics describing habitat and pathway quality based on their data requirements (graph-based, occupancy-based, and demographic-based metrics) and synopsize the ecological literature relating to these classes. Applying the first steps of a formal decision-making approach (problem framing, objectives, and management actions), we assess the utility of metrics for particular types of management decisions. Our framework can help managers with problem framing, choosing metrics of habitat and pathway quality, and to elucidate the data needs for a particular metric. Our goal is to help managers to narrow the range of suitable metrics for a management project, and aid in decision-making to make the best use of limited resources.

  2. Inbreeding in stochastic subdivided mating systems: the genetic consequences of host spatial structure, aggregated transmission dynamics and life history characteristics in parasite populations

    Indian Academy of Sciences (India)

    Guha Dharmarajan

    2015-03-01

    Inbreeding in parasite populations can have important epidemiological and evolutionary implications. However, theoretical models have predominantly focussed on the evolution of parasite populations under strong selection or in epidemic situations, and our understanding of neutral gene dynamics in parasite populations at equilibrium has been limited to verbal arguments or conceptual models. This study focusses on how host–parasite population dynamics affects observed levels of inbreeding in a random sample of parasites from an infinite population of hosts by bridging traditional genetic and parasitological processes utilizing a backward–forward branching Markov process embedded within a flexible statistical framework, the logarithmic-poisson mixture model. My results indicate that levels of inbreeding in parasites are impacted by demographic and/or transmission dynamics (subdivided mating, aggregated transmission dynamics and host spatial structure), and that this inbreeding is poorly estimated by ‘equilibrium’ levels of inbreeding calculated assuming regular systems of mating. Specifically, the model reveals that at low levels of inbreeding ( ≤ 0.1), equilibrium levels of inbreeding are lower than those observed, while at high levels of inbreeding the opposite pattern occurs. The model also indicates that inbreeding could have important epidemiological implications (e.g., the spread of recessive drug resistance genes) by directly impacting the observed frequency of rare homozygotes in parasite populations. My results indicate that frequencies of rare homozygotes are affected by aggregated transmission dynamics and host spatial structure, and also that an increase in the frequency of rare homozygotes can be caused by a decrease in effective population size solely due to the presence of a subdivided breeding system.

  3. Spatial patterns of neutral and functional genetic variations reveal patterns of local adaptation in raccoon (Procyon lotor) populations exposed to raccoon rabies.

    Science.gov (United States)

    Kyle, Christopher J; Rico, Yessica; Castillo, Sarrah; Srithayakumar, Vythegi; Cullingham, Catherine I; White, Bradley N; Pond, Bruce A

    2014-05-01

    Local adaptation is necessary for population survival and depends on the interplay between responses to selective forces and demographic processes that introduce or retain adaptive and maladaptive attributes. Host-parasite systems are dynamic, varying in space and time, where both host and parasites must adapt to their ever-changing environment in order to survive. We investigated patterns of local adaptation in raccoon populations with varying temporal exposure to the raccoon rabies virus (RRV). RRV infects approximately 85% of the population when epizootic and has been presumed to be completely lethal once contracted; however, disease challenge experiments and varying spatial patterns of RRV spread suggest some level of immunity may exist. We first assessed patterns of local adaptation in raccoon populations along the eastern seaboard of North America by contrasting spatial patterns of neutral (microsatellite loci) and functional, major histocompatibility complex (MHC) genetic diversity and structure. We explored variation of MHC allele frequencies in the light of temporal population exposure to RRV (0-60 years) and specific RRV strains in infected raccoons. Our results revealed high levels of MHC variation (66 DRB exon 2 alleles) and pronounced genetic structure relative to neutral microsatellite loci, indicative of local adaptation. We found a positive association linking MHC genetic diversity and temporal RRV exposure, but no association with susceptibility and resistance to RRV strains. These results have implications for landscape epidemiology studies seeking to predict the spread of RRV and present an example of how population demographics influence the degree to which populations adapt to local selective pressures. PMID:24655158

  4. The effects of spatial and temporal heterogeneity on the population dynamics of four animal species in a Danish landscape

    OpenAIRE

    Forchhammer Mads C; Nabe-Nielsen Jacob; Sibly Richard M; Forbes Valery E; Topping Christopher J

    2009-01-01

    Abstract Background Variation in carrying capacity and population return rates is generally ignored in traditional studies of population dynamics. Variation is hard to study in the field because of difficulties controlling the environment in order to obtain statistical replicates, and because of the scale and expense of experimenting on populations. There may also be ethical issues. To circumvent these problems we used detailed simulations of the simultaneous behaviours of interacting animals...

  5. 北京城市人口空间分布特征的GIS分析%Analyzing Urban Population Spatial Distribution in Beijing Proper

    Institute of Scientific and Technical Information of China (English)

    匡文慧; 杜国明

    2011-01-01

    Analysis of urban population distribution due to urbanization at local scale is important contents in studying human-environment interaction. Based on the urban geographical information framework, in this research we used the fifth population census data of 2000 and urban building spatial data extracted from aerial photos, to simulate population spatial distribution with 300m-gird using GIS grid technology. Then we analyzed population spatial distribution and variability at different scales. The results indicated that, from the macro-view analysis, the ring-roads system had a significant influence on population distribution, that is, considerably different densities among the ring roads with integral decreasing gradients from inner- to out-ring roads. From the micro-view analysis, population distribution had spatial agglomeration and autocorrelation. The micro-scale variation accounted for less proportion in the whole variation. From the middle-view analysis, population distribution appeared strong step-down fluctuations from the city center to the periphery. Within the ranges of 0 - 8. 5, 8. 5 -13. 5 and 13. 5 - 33. 0 km, population density showed parabolas with downhill hatch. Meanwhile, population density showed a reduction trend for a long distance but an increase for a short distance. So we concluded that population spatial distribution in Beijing had "single-center and Scattering wave" characteristics, a distinct difference comparing to other urban population distribution.%城市人口空间分布特征分析是城市化影响下的局地尺度人类-环境(Human-Environment)相互作用研究的一个重要内容.本研究以第五次人口普查数据,采用GIS网格计算方法,模拟北京市2000年人口空间分布,并从宏观、微观、中观3个不同层次分析其空间分布与变异特征.研究表明,从宏观角度分析,各环路间人口密度具有较大的差异,自内向外整体上呈现先增加后减少的

  6. Temporal and spatial variations in wildlife population fluctuations in Greenland; The effect of climate, environment and man

    DEFF Research Database (Denmark)

    Moshøj, Charlotte Margaret; Forchhammer, Mads C.; Forbes, Valery E.

    2009-01-01

    underlying factors of species fluctuating population dynamics has been the dominant focus of attention in population ecology throughout much of this century. In arctic regions where a severe climate with high seasonal and annual variability and simplistic ecosystems prevail, species of fish, birds and...... factors driving species population dynamics, the relative contributions and potential interactions among these factors remains unsolved. In Greenland, these fluctuations in the harvests of individual species are believed to be related to changes in climate, as well as variations in hunting pressure...... results of this study will model future predictions of wildlife populations under changing climate variables and human hunting pressure....

  7. Spatially Extensive Standardized Surveys Reveal Widespread, Multi-Decadal Increase in East Antarctic Adélie Penguin Populations

    Science.gov (United States)

    Southwell, Colin; Emmerson, Louise; McKinlay, John; Newbery, Kym; Takahashi, Akinori; Kato, Akiko; Barbraud, Christophe; DeLord, Karine; Weimerskirch, Henri

    2015-01-01

    Seabirds are considered to be useful and practical indicators of the state of marine ecosystems because they integrate across changes in the lower trophic levels and the physical environment. Signals from this key group of species can indicate broad scale impacts or response to environmental change. Recent studies of penguin populations, the most commonly abundant Antarctic seabirds in the west Antarctic Peninsula and western Ross Sea, have demonstrated that physical changes in Antarctic marine environments have profound effects on biota at high trophic levels. Large populations of the circumpolar-breeding Adélie penguin occur in East Antarctica, but direct, standardized population data across much of this vast coastline have been more limited than in other Antarctic regions. We combine extensive new population survey data, new population estimation methods, and re-interpreted historical survey data to assess decadal-scale change in East Antarctic Adélie penguin breeding populations. We show that, in contrast to the west Antarctic Peninsula and western Ross Sea where breeding populations have decreased or shown variable trends over the last 30 years, East Antarctic regional populations have almost doubled in abundance since the 1980’s and have been increasing since the earliest counts in the 1960’s. The population changes are associated with five-year lagged changes in the physical environment, suggesting that the changing environment impacts primarily on the pre-breeding age classes. East Antarctic marine ecosystems have been subject to a number of changes over the last 50 years which may have influenced Adélie penguin population growth, including decadal-scale climate variation, an inferred mid-20th century sea-ice contraction, and early-to-mid 20th century exploitation of fish and whale populations. PMID:26488299

  8. 听障和听力正常人群空间主导性和空间参照框架的交互作用%Interaction between spatial domain and spatial reference frame in deaf and hearing populations

    Institute of Scientific and Technical Information of China (English)

    王爱君; 沈路; 迟莹莹; 刘晓乐; 陈骐; 张明

    2016-01-01

    Spatial location of an object can be represented in the human brain based on allocentric and egocentric reference frames. The perception/action hypothesis of the ventral and dorsal visual streams proposed that egocentric representations are readily encoded in the dorsal stream as sensorimotor representations, and allocentric representations are encoded in the ventral stream as perceptual representations. In addition, the dorsal visual stream, which transforms visual information into sensorimotor representations is implicated in near-space processing, and the ventral stream, which transforms visual information into perceptual representations is involved in the conscious perception of objects in far space. It has been well documented that how the spatial domain and spatial reference frame works, separately. However, it remains poorly understood how the spatial domain interacts with spatial reference frame, especially for the deaf populations. In present study, we synchronously operated different spatial domains (near vs. far) and different spatial reference frames (egocentric vs. allocentric) to investigate the potential interactions in deaf and hearing populations. By asking 17 congenitally deaf participants and 17 hearing participants to perform allocentric and egocentric judgment tasks on the same stimulus set in near and far spaces, respectively, forming a 2 by 2 factorial design in Experiment 1. The stimuli in each trial contained two 3-D objects: a fork on the top of a round orange plate. In near space, stimuli were presented on a screen with the eye-to-screen distance as 50 cm, and in far space, stimuli were presented via a projector on a screen with the eye-to-screen distance as 226 cm. Retinotopic sizes of the objects and visual angles of the egocentric and allocentric distances were both matched for near and far spaces. To test the sense of balance was impaired in the deaf group of the present experiment, we asked both groups to perform a open loop pointing

  9. Population-based surveillance of pediatric pneumonia: use of spatial analysis in an urban area of Central Brazil

    Directory of Open Access Journals (Sweden)

    Andrade Ana Lúcia Sampaio Sgambatti de

    2004-01-01

    Full Text Available This study examined the spatial distribution of childhood community-acquired pneumonia detected through prospective surveillance in Goiânia, Brazil. Three spatial analysis techniques were applied to detect intra-urban geographic aggregation of pneumonia cases: Kernel method, nearest neighbor hierarchical technique, and spatial scan statistic. A total of 724 pneumonia cases confirmed by chest radiography were identified from May 2000 to August 2001. All cases were geocoded on a digital map. The annual pneumonia risk rate was estimated at 566 cases/100,000 children. Analysis using traditional descriptive epidemiology showed a mosaic distribution of pneumonia rates, while GIS methodologies showed a non-random pattern with hot spots of pneumonia. Cluster analysis by spatial scan statistic identified two high-risk areas for pneumonia occurrence, including one most likely cluster (RR = 2.1; p < 0.01 and one secondary cluster (RR = 1.3; p = 0.01. The data used for the study are in line with recent WHO-led efforts to improve and standardize pediatric pneumonia surveillance in developing countries and show how GIS and spatial analysis can be applied to discriminate target areas of pneumonia for public heath intervention.

  10. Spatial and temporal variation in the abundance, distribution and population structure of epibenthic megafauna in Port Foster, Deception Island

    Science.gov (United States)

    Cranmer, T. L.; Ruhl, H. A.; Baldwin, R. J.; Kaufmann, R. S.

    2003-06-01

    Abundance and spatial distribution of epibenthic megafauna were examined at Port Foster, Deception Island, five times between March 1999 and November 2000. Camera sled surveys and bottom trawls were used to identify and collect specimens, and camera sled photographs also were used to determine abundances and spatial distributions for each species. The ophiuroid Ophionotus victoriae, the regular echinoid Sterechinus neumayeri, and one or more species of Porifera were the most abundant taxa during this sampling period. Abundances of O. victoriae varied throughout the annual cycle, peaking in June 2000, and were correlated positively with sedimentation rates. In contrast, abundances of S. neumayeri were consistent throughout the sampling period, except for a peak in June 2000, during austral winter. Peak abundances for both species coincided with a large number of small individuals, indicating apparent recruitment events for O. victoriae and S. neumayeri during this time period. Poriferans, as a group, had statistically similar abundances during each sampling period. Low-abundance species tended to be aggregated on both small and large spatial scales, their distributions probably influenced by reproductive method, gregarious settlement, and food availability. The spatial distribution of S. neumayeri in June 2000 and O. victoriae was random across multiple spatial scales, perhaps in response to food availability and broad environmental tolerances, respectively.

  11. Holocene paleoenvironmental reconstruction in the Eastern Amazonian Basin: Comprido Lake

    Science.gov (United States)

    Moreira, L. S.; Moreira-Turcq, P.; Cordeiro, R. C.; Turcq, B.; Caquineau, S.; Viana, J. C. C.; Brandini, N.

    2013-07-01

    Two sediment cores were studied from Comprido Lake, a black water floodplain lake located near Monte Alegre City, Eastern Amazonian Basin. The total organic carbon (TOC), nitrogen content (TN), δ13CTOC, sedimentary chlorophyll, diatom record and mineralogical composition revealed different hydrological and climatic regimes during the Holocene. Between 10,300 and 7800 cal yr BP, a dry climate was suggested by low values of TOC and chlorophyll derivatives concentrations that are related to the development of a C4 grasses on unflooded mud banks. A gap in sedimentation due to a complete dryness of the lake occurred between 7800 and 3000 cal years BP corresponding to the Middle Holocene dry phase. From 3000 cal years BP onwards a gradual increase of the TOC, chlorophyll derivatives and Aulacoseira sp. suggest an increase in the productivity and in water lake level due to the high water flow of the Amazon River and the catchment area as well. The Comprido Lake record indicates that the Late Holocene in this region was characterized by a wetter climate, as also observed in other records of the Amazonian Basin.

  12. Sustainable development, social organization and environment in the Amazonian Area

    International Nuclear Information System (INIS)

    The effects of the development on the environment and the culture in regions like the Amazonian are one of the most dramatic examples that can be in what refers to the physical disappearance of numerous cultures, as well as of their integration to the national society and their rising loss of cultural identity and the devastating consequences that have had the development politicians on the different Amazon ecosystems. The construction of a sustainable development for the region has to evaluate the different societies that have existed and they exist as for the use, handling and exploitation of the natural resources. This paper will be approached this problem in three Amazon societies: the cacique territory, the tribal societies and the societies in formation in the colonization regions. It will be done an analysis and a critic of the development concept and of the consequences that it has had their application so much in the indigenous towns as in the Amazon ecosystems, as well as their relationship with the current characterization of the Amazonian area

  13. Prospects for malaria elimination in non-Amazonian regions of Latin America.

    Science.gov (United States)

    Herrera, Sócrates; Quiñones, Martha Lucia; Quintero, Juan Pablo; Corredor, Vladimir; Fuller, Douglas O; Mateus, Julio Cesar; Calzada, Jose E; Gutierrez, Juan B; Llanos, Alejandro; Soto, Edison; Menendez, Clara; Wu, Yimin; Alonso, Pedro; Carrasquilla, Gabriel; Galinski, Mary; Beier, John C; Arévalo-Herrera, Myriam

    2012-03-01

    Latin America contributes 1-1.2 million clinical malaria cases to the global malaria burden of about 300 million per year. In 21 malaria endemic countries, the population at risk in this region represents less than 10% of the total population exposed worldwide. Factors such as rapid deforestation, inadequate agricultural practices, climate change, political instability, and both increasing parasite drug resistance and vector resistance to insecticides contribute to malaria transmission. Recently, several malaria endemic countries have experienced a significant reduction in numbers of malaria cases. This is most likely due to actions taken by National Malaria Control Programs (NMCP) with the support from international funding agencies. We describe here the research strategies and activities to be undertaken by the Centro Latino Americano de Investigación en Malaria (CLAIM), a new research center established for the non-Amazonian region of Latin America by the National Institute of Allergy and Infectious Diseases (NIAID). Throughout a network of countries in the region, initially including Colombia, Guatemala, Panama, and Peru, CLAIM will address major gaps in our understanding of changing malaria epidemiology, vector biology and control, and clinical malaria mainly due to Plasmodium vivax. In close partnership with NMCPs, CLAIM seeks to conduct research on how and why malaria is decreasing in many countries of the region as a basis for developing and implementing new strategies that will accelerate malaria elimination. PMID:21781953

  14. Population substructure in Finland and Sweden revealed by the use of spatial coordinates and a small number of unlinked autosomal SNPs

    Directory of Open Access Journals (Sweden)

    Lindgren Cecilia M

    2008-08-01

    Full Text Available Abstract Background Despite several thousands of years of close contacts, there are genetic differences between the neighbouring countries of Finland and Sweden. Within Finland, signs of an east-west duality have been observed, whereas the population structure within Sweden has been suggested to be more subtle. With a fine-scale substructure like this, inferring the cluster membership of individuals requires a large number of markers. However, some studies have suggested that this number could be reduced if the individual spatial coordinates are taken into account in the analysis. Results We genotyped 34 unlinked autosomal single nucleotide polymorphisms (SNPs, originally designed for zygosity testing, from 2044 samples from Sweden and 657 samples from Finland, and 30 short tandem repeats (STRs from 465 Finnish samples. We saw significant population structure within Finland but not between the countries or within Sweden, and isolation by distance within Finland and between the countries. In Sweden, we found a deficit of heterozygotes that we could explain by simulation studies to be due to both a small non-random genotyping error and hidden substructure caused by immigration. Geneland, a model-based Bayesian clustering algorithm, clustered the individuals into groups that corresponded to Sweden and Eastern and Western Finland when spatial coordinates were used, whereas in the absence of spatial information, only one cluster was inferred. Conclusion We show that the power to cluster individuals based on their genetic similarity is increased when including information about the spatial coordinates. We also demonstrate the importance of estimating the size and effect of genotyping error in population genetics in order to strengthen the validity of the results.

  15. Spatial Amphibian Impact Assessment – a management tool for assessment of road effects on regional populations of Moor frogs (Rana arvalis

    Directory of Open Access Journals (Sweden)

    Maj-Britt Pontoppidan

    2013-11-01

    Full Text Available An expanding network of roads and railways fragments natural habitat affecting the amount and quality of habitat and reducing connectivity between habitat patches with severe consequences for biodiversity and population persistence. To ensure an ecologically sustainable transportation system it is essential to find agreement between nature conservation and land use. However, sustainable road planning requires adequate tools for assessment, prevention and mitigation of the impacts of infrastructure. In this study, we present a spatially explicit model, SAIA (Spatial Amphibian Impact Assessment, to be used as a standardized and quantitative tool for assessing the impact of roads on pond-breeding amphibians. The model considers a landscape mosaic of breeding habitat, summer habitat and uninhabitable land. As input, we use a GIS-map of the landscape with information on land cover as well as data on observed frog populations in the survey area. The dispersal of juvenile frogs is simulated by means of individual-based modelling, while a population-based model is used for simulating population dynamics. In combination the two types of models generate output on landscape connectivity and population viability. Analyses of maps without the planned road constructions will constitute a “null-model” against which other scenarios can be compared, making it possible to assess the effect of road projects on landscape connectivity and population dynamics. Analyses and comparisons of several alternative road projects can identify the least harmful solution. The effect of mitigation measures, such as new breeding ponds and underpasses, can be evaluated by incorporating them in the maps, thereby enhancing the utility of the model as a management tool in Environmental Impact Assessments. We demonstrate how SAIA can be used to assess which management measures would be best to mitigate the effect of landscape fragmentation caused by road constructions by means of

  16. Amazonian volcanic activity at the Syrtis volcanic province, Mars

    Science.gov (United States)

    Platz, Thomas; Jodlowski, Piotr; Fawdon, Peter; Michael, Greg; Tanaka, Kenneth

    2014-05-01

    The Syrtis Major volcanic province, including the entire Syrtis Major Planum, is located near the Martian highland/lowland transitional zone west of Isidis Planitia. It covers ≡7.4×105 km2 and contains two low-shield volcanic edifices with N-S elongated calderas named Nili and Meroe Paterae. The estimated thickness of erupted material in the province ranges from approximately 0.5 km to 1.0 km with a total volume of about 1.6-3.2×105 km3 [1]. The timing of volcanic activity in the Syrtis Major volcanic province has been suggested to be restricted to the Hesperian Period [1-4]. In the geological map of Greeley and Guest [2], volcanic material of Syrtis Major was assigned an Hesperian age based on the density of observed craters larger than 5 km in diameter. Using the same crater density range, recent studies of Hiesinger et al. [1] and Tanaka et al. [3] and Tanaka et al. [4] assigned an Early Hesperian and Early to Late Hesperian age, respectively, for the entire province. In this study we mapped lava flows, lava channels, and major lava-flow margins and report model ages for lava-flow formation and caldera segments of Nili and Meroe Paterae. The objective of this ongoing survey is to better understand the eruption frequency of this volcanic province. In total, we mapped 67 lava flows, caldera segments, and intra-crater fillings of which 55 were dated. Crater size-frequency distributions (CSFD) were mapped on HRSC and CTX imagery using CraterTools [5]. CSFDs were analyzed and model ages determined in Craterstats [6] using the production and chronology functions of Ivanov [7] and Hartmann and Neukum [8], respectively. A detailed description of the utilization of the crater-counting technique and its limitations with respect to small-scale mapping is given in Platz et al. [9]. Model ages range between 838 Ma (Middle Amazonian) to 3.6 Ga (Late Hesperian). In our survey, a broad age peak occurs between 2 to 2.6 Ga, continuously declining thereafter. We note that

  17. The influences of CO2 fertilization and land use change on the total aboveground biomass in Amazonian tropical forest

    Science.gov (United States)

    Castanho, A. D.; Zhang, K.; Coe, M. T.; Costa, M. H.; Moorcroft, P. R.

    2012-12-01

    Field observations from undisturbed old-growth Amazonian forest plots have recently reported on the temporal variation of many of the physical and chemical characteristics such as: physiological properties of leaves, above ground live biomass, above ground productivity, mortality and turnover rates. However, although this variation has been measured, it is still not well understood what mechanisms control the observed temporal variability. The observed changes in time are believed to be a result of a combination of increasing atmospheric CO2 concentration, climate variability, recovery from natural disturbance (drought, wind blow, flood), and increase of nutrient availability. The time and spatial variability of the fertilization effect of CO2 on above ground biomass will be explored in more detail in this work. A precise understanding of the CO2 effect on the vegetation is essential for an accurate prediction of the future response of the forest to climate change. To address this issue we simultaneously explore the effects of climate variability, historical CO2 and land-use change on total biomass and productivity using two different Dynamic Global Vegetation Models (DGVM). We use the Integrated Biosphere Simulator (IBIS) and the Ecosystem Demography Model 2.1 (ED2.1). Using land use changes database from 1700 - 2008 we reconstruct the total carbon balance in the Amazonian forest in space and time and present how the models predict the forest as carbon sink or source and explore why the model and field data diverge from each other. From 1970 to 2005 the Amazonian forest has been exposed to an increase of approximately 50 ppm in the atmospheric CO2 concentration. Preliminary analyses with the IBIS and ED2.1 dynamic vegetation model shows the CO2 fertilization effect could account for an increase in above ground biomass of 0.03 and 0.04 kg-C/m2/yr on average for the Amazon basin, respectively. The annual biomass change varies temporally and spatially from about 0

  18. Spatial distribution and esterase activity in populations of Aedes (Stegomyia aegypti (Linnaeus (Diptera: Culicidae resistant to temephos

    Directory of Open Access Journals (Sweden)

    Wanessa Porto Tito Gambarra

    2013-04-01

    Full Text Available INTRODUCTION: The need for studies that describe the resistance patterns in populations of Aedes aegypti (Linnaeus in function of their region of origin justified this research, which aimed to characterize the resistance to temephos and to obtain information on esterase activity in populations of Aedes aegypti collected in municipalities of the State of Paraíba. METHODS: Resistance to temephos was evaluated and characterized from the diagnostic dose of 0.352mg i.a./L and multiple concentrations that caused mortalities between 5% and 99%. Electrophoresis of isoenzymes was used to verify the patterns of esterase activity among populations of the vector. RESULTS: All populations of Aedes aegypti were resistant to temephos, presenting a resistance rate (RR greater than 20. The greatest lethal dose 50% of the sample (CL50 was found for the municipality of Lagoa Seca, approximately forty-one times the value of CL50 for the Rockefeller population. The populations characterized as resistant showed two to six regions of α and β-esterase, called EST-1 to EST-6, while the susceptible population was only seen in one region of activity. CONCLUSIONS: Aedes aegypti is widely distributed and shows a high degree of resistance to temephos in all municipalities studied. In all cases, esterases are involved in the metabolism and, consequently, in the resistance to temephos.

  19. Spatial distribution and esterase activity in populations of Aedes (Stegomyia aegypti (Linnaeus (Diptera: Culicidae resistant to temephos

    Directory of Open Access Journals (Sweden)

    Wanessa Porto Tito Gambarra

    2013-09-01

    Full Text Available INTRODUCTION: The need for studies that describe the resistance patterns in populations of Aedes aegypti (Linnaeus in function of their region of origin justified this research, which aimed to characterize the resistance to temephos and to obtain information on esterase activity in populations of Aedes aegypti collected in municipalities of the State of Paraíba. METHODS: Resistance to temephos was evaluated and characterized from the diagnostic dose of 0.352mg i.a./L and multiple concentrations that caused mortalities between 5% and 99%. Electrophoresis of isoenzymes was used to verify the patterns of esterase activity among populations of the vector. RESULTS: All populations of Aedes aegypti were resistant to temephos, presenting a resistance rate (RR greater than 20. The greatest lethal dose 50% of the sample (CL50 was found for the municipality of Lagoa Seca, approximately forty-one times the value of CL50 for the Rockefeller population. The populations characterized as resistant showed two to six regions of α and β-esterase, called EST-1 to EST-6, while the susceptible population was only seen in one region of activity. CONCLUSIONS: Aedes aegypti is widely distributed and shows a high degree of resistance to temephos in all municipalities studied. In all cases, esterases are involved in the metabolism and, consequently, in the resistance to temephos.

  20. Spatial behaviour of little owls (Athene noctua) in a declining low-density population in Denmark

    DEFF Research Database (Denmark)

    Sunde, Peter; Thorup, Kasper; Jacobsen, Lars Bo;

    2009-01-01

    Knowledge of a species' spatial behaviour is essential for understanding its behavioural ecology and a prerequisite to planning of conservation strategies. The little owl has shown a substantial decline in North-western Europe and is on the road of extinction in Denmark. To quantify relevant aspe...

  1. Proof of the Post-drought Effect of Amazonian Forests from Space

    Science.gov (United States)

    Yang, Y.; Saatchi, S. S.; Xu, L.; Yu, Y.; Myneni, R. B.; Knyazikhin, Y.; CHOI, S.

    2015-12-01

    In 2005, the tropical forests in Amazonia went through a severe drought event across the entire basin. There have been conflict reports on the drought impact on vegetation and the issue was never settled due to limited ground truth. Remote sensing data have been used but often questioned for signal saturation, data quality, or atmosphere contamination. The quantification of carbon changes in this vast terrestrial carbon pool, especially the post-drought effect, is difficult but essential. Lidar measurements, which are regarded as the accurate retrieval of canopy vertical structure, give us the opportunity to quantify the carbon changes for this severe event. Here, we use the lidar waveforms measured from the GLAS sensor from 2004 to 2007 to calculate the vertical profiles of Amazonian forests and their associated carbon stock. After careful quality-filtering, removal of seasonal effect, as well as uncertainty reduction through spatial averaging and random sampling, we find that the mean canopy height in Amazon has much higher reduction from 2006 to 2007 compared to either the drought year from 2004 to 2005, or the immediate post-drought change from 2005 to 2006, demonstrating a lagged effect of drought. Our estimation of carbon loss from model calculation also show that 2005 drought had an significant impact on the carbon exchange, and emissions from post drought disturbance may match the emissions of annual deforestation from Amazonia.

  2. Responses of squirrel monkeys to seasonal changes in food availability in an eastern Amazonian forest.

    Science.gov (United States)

    Stone, Anita I

    2007-02-01

    Tropical forests are characterized by marked temporal and spatial variation in productivity, and many primates face foraging problems associated with seasonal shifts in fruit availability. In this study, I examined seasonal changes in diet and foraging behaviors of two groups of squirrel monkeys (Saimiri sciureus), studied for 12 months in Eastern Brazilian Amazonia, an area characterized by seasonal rainfall. Squirrel monkeys were primarily insectivorous (79% of feeding and foraging time), with fruit consumption highest during the rainy season. Although monkeys fed from 68 plant species, fruit of Attalea maripa palms accounted for 28% of annual fruit-feeding records. Dietary shifts in the dry season were correlated with a decline in ripe A. maripa fruits. Despite pronounced seasonal variation in rainfall and fruit abundance, foraging efficiency, travel time, and distance traveled remained stable between seasons. Instead, squirrel monkeys at this Eastern Amazonian site primarily dealt with the seasonal decline in fruit by showing dietary flexibility. Consumption of insects, flowers, and exudates increased during the dry season. In particular, their foraging behavior at this time strongly resembled that of tamarins (Saguinus sp.) and consisted of heavy use of seed-pod exudates and specialized foraging on large-bodied orthopterans near the forest floor. Comparisons with squirrel monkeys at other locations indicate that, across their geographic range, Saimiri use a variety of behavioral tactics during reduced periods of fruit availability. PMID:17154390

  3. Spatial analysis of wing geometry in dengue vector mosquito, Aedes aegypti (L. (Diptera: Culicidae, populations in Metropolitan Manila, Philippines

    Directory of Open Access Journals (Sweden)

    Thaddeus M Carvajal

    2016-01-01

    Interpretation & conclusion: The newly modified wing preparation procedure was able to capture a complete coverage of the wings of Ae. aegypti, thus providing a stronger separation power for very close populations in an urban area. It is also noteworthy that the results of IBD and SA supported the findings of GM in the population structuring of male and female Ae. aegypti. The outcome of the study increases our understanding of the vector, which would be useful in developing effective control strategies.

  4. Spatial distribution and esterase activity in populations of Aedes (Stegomyia) aegypti (Linnaeus) (Diptera: Culicidae) resistant to temephos

    OpenAIRE

    Wanessa Porto Tito Gambarra; Walter Fabrício Silva Martins; Maurício Lilioso de Lucena Filho; Ingredy Meneses Cavalcanti de Albuquerque; Otávia Karla dos Santos Apolinário; Eduardo Barbosa Beserra

    2013-01-01

    INTRODUCTION: The need for studies that describe the resistance patterns in populations of Aedes aegypti (Linnaeus) in function of their region of origin justified this research, which aimed to characterize the resistance to temephos and to obtain information on esterase activity in populations of Aedes aegypti collected in municipalities of the State of Paraíba. METHODS: Resistance to temephos was evaluated and characterized from the diagnostic dose of 0.352mg i.a...

  5. Mating system, pollen and propagule dispersal, and spatial genetic structure in a high-density population of the mangrove tree Kandelia candel.

    Science.gov (United States)

    Geng, Qifang; Lian, Chunlan; Goto, Susumu; Tao, Jianmin; Kimura, Megumi; Islam, Md Sajedul; Hogetsu, Taizo

    2008-11-01

    Mangrove tree species form ecologically and economically important forests along the tropical and subtropical coastlines of the world. Although low intrapopulation genetic diversity and high interpopulation genetic differentiation have been detected in most mangrove tree species, no direct investigation of pollen and propagule dispersal through paternity and/or parentage analysis and spatial genetic structure within populations has been conducted. We surveyed the mating system, pollen and propagule dispersal, and spatial genetic structure in a natural population of Kandelia candel, one of the typical viviparous mangrove tree species, using nuclear and chloroplast microsatellite markers. High diversity and outcrossing rates were observed. Paternity and parentage analysis and modelling estimations revealed the presence of an extremely short-distance component of pollen and propagule dispersal (pollen: 15.2+/-14.9 m (SD) by paternity analysis and 34.4 m by modelling; propagule: 9.4+/-13.8 m (SD) by parentage analysis, and 18.6 m by modelling). Genetic structure was significant at short distances, and a clumped distribution of chloroplast microsatellite genotypes was seen in K. candel adults. We conclude that the K. candel population was initiated by limited propagule founders from outside by long-distance dispersal followed by limited propagule dispersal from the founders, resulting in a half-sib family structure. PMID:19140988

  6. Spatial and temporal variation in population dynamics of Andean frogs: Effects of forest disturbance and evidence for declines

    Directory of Open Access Journals (Sweden)

    Esther M. Cole

    2014-08-01

    Full Text Available Biodiversity loss is a global phenomenon that can result in the collapse of food webs and critical ecosystem services. Amphibian population decline over the last century is a notable case of species loss because amphibians survived the last four major extinction events in global history, their current rate of extinction is unprecedented, and their rate of extinction is greater than that for most other taxonomic groups. Despite the severity of this conservation problem and its relevance to the study of global biodiversity loss, major knowledge gaps remain for many of the most threatened species and regions in the world. Rigorous estimates of population parameters are lacking for many amphibian species in the Neotropics. The goal of our study was to determine how the demography of seven species of the genus Pristimantis varied over time and space in two cloud forests in the Ecuadorian Andes. We completed a long term capture–mark–recapture study to estimate abundance, survival, and population growth rates in two cloud forests in the Ecuadorian Andes; from 2002 to 2009 at Yanayacu in the Eastern Cordillera and from 2002 to 2003 at Cashca Totoras in the Western Cordillera. Our results showed seasonal and annual variation in population parameters by species and sex. P. bicantus experienced significant reductions in abundance over the course of our study. Abundance, apparent survival, and population growth rates were lower in disturbed than in primary or mature secondary forest. The results of our study raise concerns for the population status of understudied amphibian groups and provide insights into the population dynamics of Neotropical amphibians.

  7. Spatial Amphibian Impact Assessment – a management tool for assessment of road effects on regional populations of Moor frogs (Rana arvalis)

    DEFF Research Database (Denmark)

    Pontoppidan, Maj-Britt; Nachman, Gøsta Støger

    2013-01-01

    An expanding network of roads and railways fragments natural habitat affecting the amount and quality of habitat and reducing connectivity between habitat patches with severe consequences for biodiversity and population persistence. To ensure an ecologically sustainable transportation system it is...... essential to find agreement between nature conservation and land use. However, sustainable road planning requires adequate tools for assessment, prevention and mitigation of the impacts of infrastructure. In this study, we present a spatially explicit model, SAIA (Spatial Amphibian Impact Assessment), to be...... used as a standardized and quantitative tool for assessing the impact of roads on pond-breeding amphibians. The model considers a landscape mosaic of breeding habitat, summer habitat and uninhabitable land. As input, we use a GIS-map of the landscape with information on land cover as well as data on...

  8. Geostatistical analysis of disease data: accounting for spatial support and population density in the isopleth mapping of cancer mortality risk using area-to-point Poisson kriging

    Directory of Open Access Journals (Sweden)

    Goovaerts Pierre

    2006-11-01

    Full Text Available Abstract Background Geostatistical techniques that account for spatially varying population sizes and spatial patterns in the filtering of choropleth maps of cancer mortality were recently developed. Their implementation was facilitated by the initial assumption that all geographical units are the same size and shape, which allowed the use of geographic centroids in semivariogram estimation and kriging. Another implicit assumption was that the population at risk is uniformly distributed within each unit. This paper presents a generalization of Poisson kriging whereby the size and shape of administrative units, as well as the population density, is incorporated into the filtering of noisy mortality rates and the creation of isopleth risk maps. An innovative procedure to infer the point-support semivariogram of the risk from aggregated rates (i.e. areal data is also proposed. Results The novel methodology is applied to age-adjusted lung and cervix cancer mortality rates recorded for white females in two contrasted county geographies: 1 state of Indiana that consists of 92 counties of fairly similar size and shape, and 2 four states in the Western US (Arizona, California, Nevada and Utah forming a set of 118 counties that are vastly different geographical units. Area-to-point (ATP Poisson kriging produces risk surfaces that are less smooth than the maps created by a naïve point kriging of empirical Bayesian smoothed rates. The coherence constraint of ATP kriging also ensures that the population-weighted average of risk estimates within each geographical unit equals the areal data for this unit. Simulation studies showed that the new approach yields more accurate predictions and confidence intervals than point kriging of areal data where all counties are simply collapsed into their respective polygon centroids. Its benefit over point kriging increases as the county geography becomes more heterogeneous. Conclusion A major limitation of choropleth

  9. Morphology, morphometry and ultrastructure of the Amazonian manatee (Sirenia: Trichechidae) spermatozoa

    OpenAIRE

    Rodrigo S. Amaral; Lucci, Carolina M; Fernando C. W. Rosas; Vera M. F. da Silva; Báo, Sônia N.

    2010-01-01

    This study describes the morphological, morphometric and ultrastructural characteristics of the Amazonian manatee Trichechus inunguis (Natterer, 1883) spermatozoon. The spermatozoa were obtained from a urine sample of an adult T. inunguis kept in captivity. The spermatozoa were analyzed by light and transmission electron microscopy. The head of Amazonian manatee spermatozoa had a flat oval shape and a well distinguishable midpiece. The mean dimensions of the spermatozoa were: head length, 7.4...

  10. Impacts of different management systems on the physical quality of an Amazonian Oxisol

    OpenAIRE

    Elaine Maria Silva Guedes; Antonio Rodrigues Fernandes; Herdjania Veras de Lima; Ademar Pereira Serra; José Ribamar Costa; Rafael da Silva Guedes

    2012-01-01

    The physical quality of Amazonian soils is relatively unexplored, due to the unique characteristics of these soils. The index of soil physical quality is a widely accepted measure of the structural quality of soils and has been used to specify the structural quality of some tropical soils, as for example of the Cerrado ecoregion of Brazil. The research objective was to evaluate the physical quality index of an Amazonian dystrophic Oxisol under different management systems. Soils under five ma...

  11. Ingestion of charcoal by the Amazonian earthworm Pontoscolex corethrurus: a potential for tropical soil fertility

    OpenAIRE

    Ponge, Jean-François; Topoliantz, Stéphanie; Ballof, Sylvain; Rossi, Jean-Pierre; Lavelle, Patrick; Betsch, Jean-Marie; Gaucher, Philippe

    2006-01-01

    International audience It is now attested that a large part of the Amazonian rain forest has been cultivated during Pre-Colombian times, using charcoal as an amendment. The incorporation of charcoal to the soil is a starting point for the formation of fertile Amazonian Dark Earths, still selected by Indian people for shifting cultivation. We showed that finely separated charcoal was commonly incorporated in the topsoil by Pontoscolex corethrurus, a tropical earthworm which thrives after bu...

  12. Fire-mediated dieback and compositional cascade in an Amazonian forest

    OpenAIRE

    Barlow, Jos; Peres, Carlos A.

    2008-01-01

    The only fully coupled land–atmosphere global climate model predicts a widespread dieback of Amazonian forest cover through reduced precipitation. Although these predictions are controversial, the structural and compositional resilience of Amazonian forests may also have been overestimated, as current vegetation models fail to consider the potential role of fire in the degradation of forest ecosystems. We examine forest structure and composition in the Arapiuns River basin in the central Braz...

  13. C dynamics in Amazonian podzols under climate change

    Science.gov (United States)

    Nunan, Naoise; Soro, Andre; Potard, Kevin; Pouteau, Valerie; Montes, Celia; Melphi, Adolpho; Lucas, Yves; Chenu, Claire

    2016-04-01

    It has recently been shown that the C stocks in Amazonian podzols are very large. They are much larger than was previously thought, particularly in the Bh horizon, which has been estimated to contain in excess of 13Pg C for Amazonia alone. It is predicted that the changes in regional climate will result in a drier soil water regime which may affect the C dynamics in these soils that are usually saturated. In order to determine the vulnerability to change of the organic C contained in the Amazonian podzols, a series of incubation experiments were established in which the effects of a number of different factors on microbial decomposition were measured. The direct effect of drier soil water regimes was tested by incubating undisturbed cores from the Bh horizon at a range of matric potentials (saturation to wilting point). Contrary to what is usually found in soils, no significant difference in mineralisation was found among matric potentials, suggesting that other factors control microbial mineralisation of this organic C. The effect of nitrogen additions, of anaerobic conditions and of the addition labile C substrate were also tested on undisturbed cores of the Bh horizon of the podzols. Samples incubated under aerobic conditions produced 3 times more CO2 than samples incubated under anaerobic conditions, whilst samples incubated under aerobic conditions with the addition of N mineralised 6.7 times more CO2 than the anaerobic samples. The addition of labile C did not have a significant effect on C mineralisation, i.e. there was no priming effect. The combined addition of labile C and mineral N did not stimulate C mineralisation more than N additions alone. By extrapolating the differences obtained here to the whole of the Amazonian podzols, it is estimated that changes in conditions which result in an increase in O2 and in N (i.e. changes in vegetation due to increases in dry periods with the establishment of a savanna for example) in the soil will cause the release

  14. Geological control of floristic composition in Amazonian forests

    Science.gov (United States)

    Higgins, Mark A; Ruokolainen, Kalle; Tuomisto, Hanna; Llerena, Nelly; Cardenas, Glenda; Phillips, Oliver L; Vásquez, Rodolfo; Räsänen, Matti

    2011-01-01

    Aim Conservation and land-use planning require accurate maps of patterns in species composition and an understanding of the factors that control them. Substantial doubt exists, however, about the existence and determinants of large-area floristic divisions in Amazonia. Here we ask whether Amazonian forests are partitioned into broad-scale floristic units on the basis of geological formations and their edaphic properties. Location Western and central Amazonia. Methods We used Landsat imagery and Shuttle Radar Topography Mission (SRTM) digital elevation data to identify a possible floristic and geological discontinuity of over 300 km in northern Peru. We then used plant inventories and soil sampling to document changes in species composition and soil properties across this boundary. Data were obtained from 138 sites distributed along more than 450 km of road and river. On the basis of our findings, we used broad-scale Landsat and SRTM mosaics to identify similar patterns across western and central Amazonia. Results The discontinuity identified in Landsat and SRTM data corresponded to a 15-fold change in soil cation concentrations and an almost total change in plant species composition. This discontinuity appears to be caused by the widespread removal of cation-poor surface sediments by river incision to expose cation-rich sediments beneath. Examination of broad-scale Landsat and SRTM mosaics indicated that equivalent processes have generated a north–south discontinuity of over 1500 km in western Brazil. Due to similarities with our study area, we suggest that this discontinuity represents a chemical and ecological limit between western and central Amazonia. Main conclusions Our findings suggest that Amazonian forests are partitioned into large-area units on the basis of geological formations and their edaphic properties. The evolution of these units through geological time may provide a general mechanism for biotic diversification in Amazonia. These compositional

  15. 基于多源空间数据的山区人口分布模拟%Simulation of Mountain Population Distribution Based on Multi -source Spatial Data

    Institute of Scientific and Technical Information of China (English)

    曹伟超; 陶和平; 谭理; 张云; 董学智

    2012-01-01

    Population resources are key factors for the development of mountain areas. The distribution conditions of population resources reflect and determine to some extent socio - economic development and sustainable development of mountainous areas. In this paper, a newer population data spatialized model for mountain areas is developed based on existing methods and factors influencing population distribution of mountain areas. Based on population census data in 2007, this paper analyzed the relationships between the distribution of residential areas and terrain, land use, roads, and rivers by using the GIS software and taking the residential area as an important indicator to population distribution. Based on multiple spatial sources data fusion technology, the authors dealt with the concept of settlements buffer, assigned the weight values of affecting factors objectively, and realized the spatialization of population census data for mountain areas completely. The result shows that there are correlations of ratio ( >0. 80) between the population density generated by data fusion and the actual population census data at the township level, and the result is reliable. The finally generated grid population density lays an important basic data foundation for the further analysis of the pattern of population distribution in mountain areas.%人口资源是制约山区发展的关键因素,其分布状况在一定程度上反映和决定了山区的资源环境安全状况和社会经济发展水平.在分析川滇黔接壤地区山区人口分布影响因素的基础上结合已有方法,构建了适合山区人口数据空间化的模型.以2007年人口统计数据为基础,以居民点作为人口分布指示因子,利用GIS软件工具,分析了居民点分布与地貌形态、土地利用、道路以及水系间的关系.基于多源空间数据融合的思想,引进了居民点缓冲区的概念,以较客观的赋权方式确定影响因子权重,实现山区人口统

  16. Spatial Ecology of the Critically Endangered Fijian Crested Iguana, Brachylophus vitiensis, in an Extremely Dense Population: Implications for Conservation

    OpenAIRE

    Morrison, Suzanne F.; Biciloa, Pita; Harlow, Peter S.; Keogh, J. Scott

    2013-01-01

    The Critically Endangered Fijian crested iguana, Brachylophus vitiensis, occurs at extreme density at only one location, with estimates of >10,000 iguanas living on the 70 hectare island of Yadua Taba in Fiji. We conducted a mark and recapture study over two wet seasons, investigating the spatial ecology and intraspecific interactions of the strictly arboreal Fijian crested iguana. This species exhibits moderate male-biased sexual size dimorphism, which has been linked in other lizard species...

  17. Exploring Spatial Associations between On-Sale Alcohol Availability, Neighborhood Population Characteristics, and Violent Crime in a Geographically Isolated City

    OpenAIRE

    Daikwon Han; Gorman, Dennis M.

    2013-01-01

    Objectives. Despite the increasing evidence of the associations between alcohol availability and violence, there are still inconsistent findings on the effects of on- and off-sale alcohol outlets on violent crime. The aim of this study was to examine spatial associations between on-sale alcohol availability, neighborhood characteristics, and violent crime in a geographically isolated city in Texas. Methods. Geographically weighted regression (GWR) and global regression models were employed to...

  18. Spatially varying selection shapes life history clines among populations of Drosophila melanogaster from sub-Saharan Africa

    OpenAIRE

    Fabian, Daniel K; Lack, Justin B.; Mathur, Vinayak; Schlötterer, Christian; Schmidt, Paul S; Pool, John E.; Flatt, Thomas

    2015-01-01

    Clines in life history traits, presumably driven by spatially varying selection, are widespread. Major latitudinal clines have been observed, for example, in Drosophila melanogaster, an ancestrally tropical insect from Africa that has colonized temperate habitats on multiple continents. Yet, how geographic factors other than latitude, such as altitude or longitude, affect life history in this species remains poorly understood. Moreover, most previous work has been performed on derived Europea...

  19. Genetic Geostatistical Framework for Spatial Analysis of Fine-Scale Genetic Heterogeneity in Modern Populations: Results from the KORA Study.

    Science.gov (United States)

    Diaz-Lacava, A N; Walier, M; Holler, D; Steffens, M; Gieger, C; Furlanello, C; Lamina, C; Wichmann, H E; Becker, T

    2015-01-01

    Aiming to investigate fine-scale patterns of genetic heterogeneity in modern humans from a geographic perspective, a genetic geostatistical approach framed within a geographic information system is presented. A sample collected for prospective studies in a small area of southern Germany was analyzed. None indication of genetic heterogeneity was detected in previous analysis. Socio-demographic and genotypic data of German citizens were analyzed (212 SNPs; n = 728). Genetic heterogeneity was evaluated with observed heterozygosity (H O ). Best-fitting spatial autoregressive models were identified, using socio-demographic variables as covariates. Spatial analysis included surface interpolation and geostatistics of observed and predicted patterns. Prediction accuracy was quantified. Spatial autocorrelation was detected for both socio-demographic and genetic variables. Augsburg City and eastern suburban areas showed higher H O values. The selected model gave best predictions in suburban areas. Fine-scale patterns of genetic heterogeneity were observed. In accordance to literature, more urbanized areas showed higher levels of admixture. This approach showed efficacy for detecting and analyzing subtle patterns of genetic heterogeneity within small areas. It is scalable in number of loci, even up to whole-genome analysis. It may be suggested that this approach may be applicable to investigate the underlying genetic history that is, at least partially, embedded in geographic data. PMID:26258132

  20. A timescale for evolution, population expansion, and spatial spread of an emerging clone of methicillin-resistant Staphylococcus aureus

    DEFF Research Database (Denmark)

    Nübel, Ulrich; Dordel, Janina; Kurt, Kevin;

    2010-01-01

    or antibiotic resistance, together with the forces driving pathogen spread. Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of hospital-acquired infections. We have investigated an MRSA strain (ST225) that is highly prevalent in hospitals in Central Europe. By using mutation discovery...... at 269 genetic loci (118,804 basepairs) within an international isolate collection, we ascertained extremely low diversity among European ST225 isolates, indicating that a recent population bottleneck had preceded the expansion of this clone. In contrast, US isolates were more divergent, suggesting...... they represent the ancestral population. While diversity was low, however, our results demonstrate that the short-term evolutionary rate in this natural population of MRSA resulted in the accumulation of measurable DNA sequence variation within two decades, which we could exploit to reconstruct its recent...

  1. Biogeography and evolution of Amazonian triatomines (Heteroptera: Reduviidae): implications for Chagas disease surveillance in humid forest ecoregions

    OpenAIRE

    Fernando Abad-Franch; Fernando A Monteiro

    2007-01-01

    An ecological-evolutionary classification of Amazonian triatomines is proposed based on a revision of their main contemporary biogeographical patterns. Truly Amazonian triatomines include the Rhodniini, the Cavernicolini, and perhaps Eratyrus and some Bolboderini. The tribe Rhodniini comprises two major lineages (pictipes and robustus). The former gave rise to trans-Andean (pallescens) and Amazonian (pictipes) species groups, while the latter diversified within Amazonia (robustus group) and r...

  2. DISPLACE: a dynamic, individual-based model for spatial fishing planning and effort displacement: Integrating underlying fish population models

    DEFF Research Database (Denmark)

    Bastardie, Francois; Nielsen, J. Rasmus; Miethe, Tanja

    advanced version couples the vessel model to selected size-based population models and considers the underlying resource dynamics in the distribution and density patterns of the targeted stocks for the cases of Danish and German vessels harvesting the North Sea and Baltic fish stocks. The stochastic...... fishing process includes direct and local depletion by stock that is specific to the vessel catching power, which is proportional to the encountered size-based population on the visited ground and is based on stock assessment and research survey data. The impact of the potential fishing effort...

  3. Local-scale spatial variation in diversity of social wasps in an Amazonian rain forest in Caxiuanã, Pará, Brazil (Hymenoptera, Vespidae, Polistinae Variação na diversidade de vespas sociais em escala local numa floresta pluvial amazônica em Caxiuanã, Pará, Brasil (Hymenoptera, Vespidae, Polistinae

    Directory of Open Access Journals (Sweden)

    Orlando Tobias Silveira

    2012-09-01

    Full Text Available Polistine wasps are important in Neotropical ecosystems due to their ubiquity and diversity. Inventories have not adequately considered spatial attributes of collected specimens. Spatial data on biodiversity are important for study and mitigation of anthropogenic impacts over natural ecosystems and for protecting species. We described and analyzed local-scale spatial patterns of collecting records of wasp species, as well as spatial variation of diversity descriptors in a 2500-hectare area of an Amazon forest in Brazil. Rare species comprised the largest fraction of the fauna. Close range spatial effects were detected for most of the more common species, with clustering of presence-data at short distances. Larger spatial lag effects could also be identified in some species, constituting probably cases of exogenous autocorrelation and candidates for explanations based on environmental factors. In a few cases, significant or near significant correlations were found between five species (of Agelaia, Angiopolybia, and Mischocyttarus and three studied environmental variables: distance to nearest stream, terrain altitude, and the type of forest canopy. However, association between these factors and biodiversity variables were generally low. When used as predictors of polistine richness in a linear multiple regression, only the coefficient for the forest canopy variable resulted significant. Some level of prediction of wasp diversity variables can be attained based on environmental variables, especially vegetation structure. Large-scale landscape and regional studies should be scheduled to address this issue.Vespas sociais são importantes nos ecossistemas neotropicais pela abundância e diversidade. A maioria dos inventários recentes não têm dedicado atenção aos atributos espaciais dos espécimes coletados. Dados espaciais são importantes para estudar e mitigar impactos sobre ecossistemas naturais e proteger espécies. Este artigo descreve e

  4. Temporal Decay in Timber Species Composition and Value in Amazonian Logging Concessions

    Science.gov (United States)

    Peres, Carlos A.

    2016-01-01

    Throughout human history, slow-renewal biological resource populations have been predictably overexploited, often to the point of economic extinction. We assess whether and how this has occurred with timber resources in the Brazilian Amazon. The asynchronous advance of industrial-scale logging frontiers has left regional-scale forest landscapes with varying histories of logging. Initial harvests in unlogged forests can be highly selective, targeting slow-growing, high-grade, shade-tolerant hardwood species, while later harvests tend to focus on fast-growing, light-wooded, long-lived pioneer trees. Brazil accounts for 85% of all native neotropical forest roundlog production, and the State of Pará for almost half of all timber production in Brazilian Amazonia, the largest old-growth tropical timber reserve controlled by any country. Yet the degree to which timber harvests beyond the first-cut can be financially profitable or demographically sustainable remains poorly understood. Here, we use data on legally planned logging of ~17.3 million cubic meters of timber across 314 species extracted from 824 authorized harvest areas in private and community-owned forests, 446 of which reported volumetric composition data by timber species. We document patterns of timber extraction by volume, species composition, and monetary value along aging eastern Amazonian logging frontiers, which are then explained on the basis of historical and environmental variables. Generalized linear models indicate that relatively recent logging operations farthest from heavy-traffic roads are the most selective, concentrating gross revenues on few high-value species. We find no evidence that the post-logging timber species composition and total value of forest stands recovers beyond the first-cut, suggesting that the commercially most valuable timber species become predictably rare or economically extinct in old logging frontiers. In avoiding even more destructive land-use patterns, managing

  5. Model gives a 3-month warning of Amazonian forest fires

    Science.gov (United States)

    Schultz, Colin

    2011-08-01

    The widespread drought suffered by the Amazon rain forest in the summer of 2005 was heralded at the time as the drought of the century. Because of the dehydrated conditions, supplemented by slash and burn agricultural practices, the drought led to widespread forest fires throughout the western Amazon, a portion of the rain forest usually too lush to support spreading wildfires. Only 5 years later, the 2005 season was outdone by even more widespread drought, with fires decimating more than 3000 square kilometers of western Amazonian rain forest. Blame for the wildfires has been consistently laid on deforestation and agricultural practices, but a convincing climatological explanation exists as well. (Geophysical Research Letters, doi:10.1029/2011GL047392, 2011)

  6. Lipase Activity among Bacteria Isolated from Amazonian Soils.

    Science.gov (United States)

    Willerding, André Luis; de Oliveira, Luiz Antonio; Moreira, Francisco Wesen; Germano, Mariana Gomes; Chagas, Aloísio Freitas

    2011-01-01

    The objective of this study was to select lipase-producing bacteria collected from different counties of the Amazon region. Of the 440 bacteria strains, 181 were selected for the lipase assay in qualitative tests at Petri dishes, being 75 (41%) lipase positive. The enzymatic index was determined during fifteen days at different temperatures (30°, 35°, 40°, and 45°C). The highest lipase activity was observed within 72 hours at 30°C. Twelve bacteria strains presented an index equal to or greater than the standard used like reference, demonstrating the potential of microbial resource. After the bioassay in Petri dishes, the selected bacteria strains were analyzed in quantitative tests on p-nitrophenyl palmitate (p-NPP). A group of the strains was selected for other phases of study with the use in oleaginous substrates of the Amazonian flora, aiming for the application in processes like oil biotransformation. PMID:22007294

  7. Lipase Activity among Bacteria Isolated from Amazonian Soils

    Directory of Open Access Journals (Sweden)

    André Luis Willerding

    2011-01-01

    Full Text Available The objective of this study was to select lipase-producing bacteria collected from different counties of the Amazon region. Of the 440 bacteria strains, 181 were selected for the lipase assay in qualitative tests at Petri dishes, being 75 (41% lipase positive. The enzymatic index was determined during fifteen days at different temperatures (30°, 35°, 40°, and 45°C. The highest lipase activity was observed within 72 hours at 30°C. Twelve bacteria strains presented an index equal to or greater than the standard used like reference, demonstrating the potential of microbial resource. After the bioassay in Petri dishes, the selected bacteria strains were analyzed in quantitative tests on p-nitrophenyl palmitate (p-NPP. A group of the strains was selected for other phases of study with the use in oleaginous substrates of the Amazonian flora, aiming for the application in processes like oil biotransformation.

  8. Cadmium in the Amazonian Guajara Estuary: Distribution and remobilization

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, S.F. [Instituto de Quimica, Departamento de Geoquimica, Universidade Federal Fluminense (Brazil)]. E-mail: nascimento@lisa.univ-paris12.fr; Kurzweil, H. [Institut fuer Petrologie, Universitaet Wien (Austria); Wruss, W. [Institut fuer Chemische Technologie anorganischer Stoffe, Technische Univesitaet Wien (Austria); Fenzl, N. [Nucleo de Altos Estudos Amazonicos, Universidade Federal do Para (Brazil)

    2006-03-15

    Extremely high total cadmium concentrations (average about 500 mg/kg) together with very small (average of 1.1 {mu}g/l) dissolved available cadmium have been found in the more acidic deeper layers of the bottom sediments of the Brazilian Amazonian Guajara Estuary. The paper shows that climatic changes and the periodic input of the Atlantic waters into the Estuary appear to have no direct influence on annual average total cadmium concentration, but they affect accumulation, distribution and remobilization of cadmium in different ways during the rainy season (February/March) and the dry season (November/December). Even if only a very small part of the total Cd is available, the concentrations of dissolved Cd in the Estuary are still high enough to cause environmental concern, if compared with concentrations in natural freshwater ecosystems. - Distribution and remobilization of cadmium is affected differently by season.

  9. Southern (DisComfort?: Latino Population Growth, Economic Integration and Spatial Assimilation in North Carolina Micropolitan Areas

    Directory of Open Access Journals (Sweden)

    Ana-María González Wahl

    2007-10-01

    Full Text Available This paper examines more closely the growth and assimilation of the Latino population in non-metropolitan areas across North Carolina. More specifically, the analysis focuses on micropolitan areas. Based on the last decennial census, micropolitan areas were newly defined by the Census Bureau to reflect the growing importance of "urban clusters" located in non-metropolitan counties.

  10. Amazonian dark Earth and plant species from the Amazon region contribute to shape rhizosphere bacterial communities.

    Science.gov (United States)

    Barbosa Lima, Amanda; Cannavan, Fabiana Souza; Navarrete, Acacio Aparecido; Teixeira, Wenceslau Geraldes; Kuramae, Eiko Eurya; Tsai, Siu Mui

    2015-05-01

    Amazonian Dark Earths (ADE) or Terra Preta de Índio formed in the past by pre-Columbian populations are highly sustained fertile soils supported by microbial communities that differ from those extant in adjacent soils. These soils are found in the Amazon region and are considered as a model soil when compared to the surrounding and background soils. The aim of this study was to assess the effects of ADE and its surrounding soil on the rhizosphere bacterial communities of two leguminous plant species that frequently occur in the Amazon region in forest sites (Mimosa debilis) and open areas (Senna alata). Bacterial community structure was evaluated using terminal restriction fragment length polymorphism (T-RFLP) and bacterial community composition by V4 16S rRNA gene region pyrosequencing. T-RFLP analysis showed effect of soil types and plant species on rhizosphere bacterial community structure. Differential abundance of bacterial phyla, such as Acidobacteria, Actinobacteria, Verrucomicrobia, and Firmicutes, revealed that soil type contributes to shape the bacterial communities. Furthermore, bacterial phyla such as Firmicutes and Nitrospira were mostly influenced by plant species. Plant roots influenced several soil chemical properties, especially when plants were grown in ADE. These results showed that differences observed in rhizosphere bacterial community structure and composition can be influenced by plant species and soil fertility due to variation in soil attributes. PMID:25103911

  11. Anthropometric measurements of adolescents from two Amazonian ecosystems: variations according to seasonality.

    Science.gov (United States)

    Silva, Hilton P; Veiga, Gloria V; Kac, Gilberto; Pereira, Rosangela A

    2010-03-01

    This paper aims to describe the nutritional status of Caboclo adolescents living in two areas of the Amazon Basin. Two cross-sectional studies, the first in the dry and the second in the wet season, were carried out in two Amazonian ecosystems: the forest and black water ecosystem, and the floodplain and white water ecosystem. Measurements of weight, stature, arm circumference and triceps, subscapular and suprailiac skinfolds were performed on 247 adolescents (10-19 years of age). Nutritional status was classified using body mass index according to international criteria and the prevalence of underweight and overweight was estimated. Linear mixed effects models were used with the anthropometric measurements as dependent variables and time interval, place of residence, sex, age and stature variation as independent variables. During the wet season, the prevalence of overweight among girls was higher in the forest (42%) than in the floodplain (9%). Longitudinal linear regression models showed that the arm circumference measurement was influenced both by seasonality and location, revealing that the increment between dry and wet seasons was less pronounced in the floodplain. At the time of the study, overweight already constituted a major public health concern among girls living in the forest area. In order to develop adequate public health policies for this important segment of the Amazon population further studies are necessary to investigate the role of environment and seasonality on the growth and nutritional status of adolescents. PMID:19906320

  12. PLOT SIZE AND APPROPRIATE SAMPLE SIZE TO STUDY NATURAL REGENERATION IN AMAZONIAN FLOODPLAIN FOREST

    Directory of Open Access Journals (Sweden)

    João Ricardo Vasconcellos Gama

    2001-01-01

    Full Text Available ABSTRACT: The aim of this study was to determine the optimum plot size as well as the appropriate sample size in order to provide an accurate sampling of natural regeneration surveys in high floodplain forests, low floodplain forests and in floodplain forests without stratification in the Amazonian estuary. Data were obtained at Exportadora de Madeira do Pará Ltda. – EMAPA forestlands, located in Afuá County, State of Pará. Based on the results, the following plot sizes were recommended: 70m2 - SC1 (0,3m ≤ h < 1,5m, 80m2 - SC2 (h ≥ 1,50m to DAP < 5,0cm, 90m2 - SC3 (5,0cm ≤ DAP < 15,0 cm and 70m2 – ASP (h ≥ 0,3m to DAP < 15,0cm. Considering these optimumplot sizes, it is possible to obtain a representative sampling of the floristic composition when using 19sub-plots in high floodplain, 14 sub-plots in low floodplain, and 19 sub-plots in the forest without stratification to survey the species of SC1 and the species of all sampled population (ASP, while 39 sub-plots are needed for sampling the natural regeneration species in SC2 and SC3.

  13. Drought sensitivity of Amazonian carbon balance revealed by atmospheric measurements.

    Science.gov (United States)

    Gatti, L V; Gloor, M; Miller, J B; Doughty, C E; Malhi, Y; Domingues, L G; Basso, L S; Martinewski, A; Correia, C S C; Borges, V F; Freitas, S; Braz, R; Anderson, L O; Rocha, H; Grace, J; Phillips, O L; Lloyd, J

    2014-02-01

    Feedbacks between land carbon pools and climate provide one of the largest sources of uncertainty in our predictions of global climate. Estimates of the sensitivity of the terrestrial carbon budget to climate anomalies in the tropics and the identification of the mechanisms responsible for feedback effects remain uncertain. The Amazon basin stores a vast amount of carbon, and has experienced increasingly higher temperatures and more frequent floods and droughts over the past two decades. Here we report seasonal and annual carbon balances across the Amazon basin, based on carbon dioxide and carbon monoxide measurements for the anomalously dry and wet years 2010 and 2011, respectively. We find that the Amazon basin lost 0.48 ± 0.18 petagrams of carbon per year (Pg C yr(-1)) during the dry year but was carbon neutral (0.06 ± 0.1 Pg C yr(-1)) during the wet year. Taking into account carbon losses from fire by using carbon monoxide measurements, we derived the basin net biome exchange (that is, the carbon flux between the non-burned forest and the atmosphere) revealing that during the dry year, vegetation was carbon neutral. During the wet year, vegetation was a net carbon sink of 0.25 ± 0.14 Pg C yr(-1), which is roughly consistent with the mean long-term intact-forest biomass sink of 0.39 ± 0.10 Pg C yr(-1) previously estimated from forest censuses. Observations from Amazonian forest plots suggest the suppression of photosynthesis during drought as the primary cause for the 2010 sink neutralization. Overall, our results suggest that moisture has an important role in determining the Amazonian carbon balance. If the recent trend of increasing precipitation extremes persists, the Amazon may become an increasing carbon source as a result of both emissions from fires and the suppression of net biome exchange by drought. PMID:24499918

  14. Spatial variations in estimated chronic exposure to traffic-related air pollution in working populations: A simulation

    Directory of Open Access Journals (Sweden)

    Cloutier-Fisher Denise

    2008-07-01

    Full Text Available Abstract Background Chronic exposure to traffic-related air pollution is associated with a variety of health impacts in adults and recent studies show that exposure varies spatially, with some residents in a community more exposed than others. A spatial exposure simulation model (SESM which incorporates six microenvironments (home indoor, work indoor, other indoor, outdoor, in-vehicle to work and in-vehicle other is described and used to explore spatial variability in estimates of exposure to traffic-related nitrogen dioxide (not including indoor sources for working people. The study models spatial variability in estimated exposure aggregated at the census tracts level for 382 census tracts in the Greater Vancouver Regional District of British Columbia, Canada. Summary statistics relating to the distributions of the estimated exposures are compared visually through mapping. Observed variations are explored through analyses of model inputs. Results Two sources of spatial variability in exposure to traffic-related nitrogen dioxide were identified. Median estimates of total exposure ranged from 8 μg/m3 to 35 μg/m3 of annual average hourly NO2 for workers in different census tracts in the study area. Exposure estimates are highest where ambient pollution levels are highest. This reflects the regional gradient of pollution in the study area and the relatively high percentage of time spent at home locations. However, for workers within the same census tract, variations were observed in the partial exposure estimates associated with time spent outside the residential census tract. Simulation modeling shows that some workers may have exposures 1.3 times higher than other workers residing in the same census tract because of time spent away from the residential census tract, and that time spent in work census tracts contributes most to the differences in exposure. Exposure estimates associated with the activity of commuting by vehicle to work were

  15. Spatial and temporal variation in population structure of Hemigrammus marginatus (Characiformes: Characidae) in streams of the Ivinhema River Basin, Brazil

    OpenAIRE

    Luzia da Silva Lourenço; Izaias Médice Fernandes; Yzel Rondon Súarez

    2012-01-01

    The present study has assessed spatial and temporal variations in the length structure of Hemigrammus marginatus Ellis, 1911 and estimated growth parameters for the species. Sampling was carried out in five streams in the Vitória and Piravevê sub-basins of the Ivinhema River from January to December 2002. A total of 933 specimens of H. marginatus were caught (97 in the Vitória sub-basin and 836 in the Piravevê sub-basin). Mean length of the individuals caught in the Piravevê sub-basin was sho...

  16. Estimating Population Size for Capercaillie (Tetrao urogallus L. with Spatial Capture-Recapture Models Based on Genotypes from One Field Sample.

    Directory of Open Access Journals (Sweden)

    Pierre Mollet

    Full Text Available We conducted a survey of an endangered and cryptic forest grouse, the capercaillie Tetrao urogallus, based on droppings collected on two sampling occasions in eight forest fragments in central Switzerland in early spring 2009. We used genetic analyses to sex and individually identify birds. We estimated sex-dependent detection probabilities and population size using a modern spatial capture-recapture (SCR model for the data from pooled surveys. A total of 127 capercaillie genotypes were identified (77 males, 46 females, and 4 of unknown sex. The SCR model yielded a total population size estimate (posterior mean of 137.3 capercaillies (posterior sd 4.2, 95% CRI 130-147. The observed sex ratio was skewed towards males (0.63. The posterior mean of the sex ratio under the SCR model was 0.58 (posterior sd 0.02, 95% CRI 0.54-0.61, suggesting a male-biased sex ratio in our study area. A subsampling simulation study indicated that a reduced sampling effort representing 75% of the actual detections would still yield practically acceptable estimates of total size and sex ratio in our population. Hence, field work and financial effort could be reduced without compromising accuracy when the SCR model is used to estimate key population parameters of cryptic species.

  17. Estimating population size for Capercaillie (Tetrao urogallus L.) with spatial capture-recapture models based on genotypes from one field sample

    Science.gov (United States)

    Mollet, Pierre; Kery, Marc; Gardner, Beth; Pasinelli, Gilberto; Royle, Andy

    2015-01-01

    We conducted a survey of an endangered and cryptic forest grouse, the capercaillie Tetrao urogallus, based on droppings collected on two sampling occasions in eight forest fragments in central Switzerland in early spring 2009. We used genetic analyses to sex and individually identify birds. We estimated sex-dependent detection probabilities and population size using a modern spatial capture-recapture (SCR) model for the data from pooled surveys. A total of 127 capercaillie genotypes were identified (77 males, 46 females, and 4 of unknown sex). The SCR model yielded atotal population size estimate (posterior mean) of 137.3 capercaillies (posterior sd 4.2, 95% CRI 130–147). The observed sex ratio was skewed towards males (0.63). The posterior mean of the sex ratio under the SCR model was 0.58 (posterior sd 0.02, 95% CRI 0.54–0.61), suggesting a male-biased sex ratio in our study area. A subsampling simulation study indicated that a reduced sampling effort representing 75% of the actual detections would still yield practically acceptable estimates of total size and sex ratio in our population. Hence, field work and financial effort could be reduced without compromising accuracy when the SCR model is used to estimate key population parameters of cryptic species.

  18. Analysing Amazonian forest productivity using a new individual and trait-based model (TFS v.1

    Directory of Open Access Journals (Sweden)

    N. M. Fyllas

    2014-02-01

    Full Text Available Repeated long-term censuses have revealed large-scale spatial patterns in Amazon Basin forest structure and dynamism, with some forests in the west of the Basin having up to a twice as high rate of aboveground biomass production and tree recruitment as forests in the east. Possible causes for this variation could be the climatic and edaphic gradients across the Basin and/or the spatial distribution of tree species composition. To help understand causes of this variation a new individual-based model of tropical forest growth designed to take full advantage of the forest census data available from the Amazonian Forest Inventory Network (RAINFOR has been developed. The model incorporates variations in tree size distribution, functional traits and soil physical properties and runs at the stand level with four functional traits, leaf dry mass per area (Ma, leaf nitrogen (NL and phosphorus (PL content and wood density (DW used to represent a continuum of plant strategies found in tropical forests. We first applied the model to validate canopy-level water fluxes at three Amazon eddy flux sites. For all three sites the canopy-level water fluxes were adequately simulated. We then applied the model at seven plots, where intensive measurements of carbon allocation are available. Tree-by-tree multi-annual growth rates generally agreed well with observations for small trees, but with deviations identified for large trees. At the stand-level, simulations at 40 plots were used to explore the influence of climate and soil fertility on the gross (ΠG and net (ΠN primary production rates as well as the carbon use efficiency (CU. Simulated ΠG, ΠN and CU were not associated with temperature. However all three measures of stand level productivity were positively related to annual precipitation and soil fertility.

  19. Implementing a generic method for bias correction in statistical models using random effects, with spatial and population dynamics examples

    DEFF Research Database (Denmark)

    Thorson, James T.; Kristensen, Kasper

    2016-01-01

    Statistical models play an important role in fisheries science when reconciling ecological theory with available data for wild populations or experimental studies. Ecological models increasingly include both fixed and random effects, and are often estimated using maximum likelihood techniques...... is calculated as a nonlinear function of random effects. We therefore describe and evaluate a new "epsilon" estimator as a generic bias-correction estimator for derived quantities. We use simulated data to compare the epsilon-method with an existing bias-correction algorithm for estimating...... recruitment in four configurations of an age-structured population dynamics model. This simulation experiment shows that the epsilon-method and the existing bias-correction method perform equally well in data-rich contexts, but the epsilon-method is slightly less biased in data-poor contexts. We then apply...

  20. Residential segregation and spatial distribution of a non-labor force population: the needy elderly and disabled.

    Science.gov (United States)

    Massey, D S

    1980-01-01

    "Processes of urban change [in the United States] were hypothesized to have created a segregated residential distribution typified by a concentration of disadvantaged and chronically unemployed individuals in decaying inner cities and the employed middle class in suburbs. This hypothesis was tested in one heavily urbanized area for a non-labor force population of needy elderly and disabled persons." Data were obtained from the Fourth Count Summary Tapes of the 1970 census PMID:12263197

  1. Mortality due to diseases of the circulatory system among the elderly population in Brazilian Amazon: temporal and spatial analysis

    OpenAIRE

    Karine Vila Real Nunes; Sandra Mara Alves da Silva Neves; Eliane Ignotti

    2013-01-01

    INTRODUCTION: Circulatory Diseases (CD) are the major cause of death among the elderly population in Brazilian Amazon. OBJECTIVE: to analyze standardized mortality rates of diseases of the circulatory system (DCS), according to the main causes of death among the elderly, in microregions of the Brazilian Amazon, in the period of 1998 - 2007. METHODS: ecological study of mortality rates distribution standardized by CD and corrected by deaths from poorly defined causes among the elderly (> 65 ye...

  2. Modeling the spatial and temporal population dynamics of the copepod Centropages typicus in the northwestern Mediterranean Sea during the year 2001 using a 3D ecosystem model

    Science.gov (United States)

    Carlotti, F.; Eisenhauer, L.; Campbell, R.; Diaz, F.

    2014-07-01

    The spatio-temporal dynamics of a simulated Centropages typicus (Kröyer) population during the year 2001 at the regional scale of the northwestern Mediterranean Sea are addressed using a 3D coupled physical-biogeochemical model. The setup of the coupled biological model comprises a pelagic plankton ecosystem model and a stage-structured population model forced by the 3D velocity and temperature fields provided by an eddy-resolving regional circulation model. The population model for C. typicus (C. t. below) represents demographic processes through five groups of developmental stages, which depend on underlying individual growth and development processes and are forced by both biotic (prey and predator fields) and abiotic (temperature, advection) factors from the coupled physical-biogeochemical model. The objective is to characterize C. t. ontogenic habitats driven by physical and trophic processes. The annual dynamics are presented for two of the main oceanographic stations in the Gulf of Lions, which are representative of shelf and open sea conditions, while the spatial distributions over the whole area are presented for three dates during the year, in early and late spring and in winter. The simulated spatial patterns of C. t. developmental stages are closely related to mesoscale hydrodynamic features and circulation patterns. The seasonal and spatial distributions on the Gulf of Lions shelf depend on the seasonal interplay between the Rhône river plume, the mesoscale eddies on the shelf and the Northern Current acting as either as a dynamic barrier between the shelf and the open sea or allowing cross-shelf exchanges. In the central gyre of the northwestern Mediterranean Sea, the patchiness of plankton is tightly linked to mesoscale frontal systems, surface eddies and filaments and deep gradients. Due to its flexibility in terms of its diet, C. t. succeeds in maintaining its population in both coastal and offshore areas year round. The simulations suggest that

  3. Guangzhou Population Spatial Distribution and Polycentricity Spatial Structure Evolution%2000-2010年广州人口空间分布变动与多中心城市空间结构演化测度

    Institute of Scientific and Technical Information of China (English)

    蒋丽; 吴缚龙

    2013-01-01

      基于广州市第五次和第六次人口普查中的常住人口数据,运用空间分析法、单中心密度模型和多中心密度模型分析法对广州市人口空间分布和多中心城市空间结构进行研究。结果表明,研究时段内广州人口空间动态变化表现为“内圈层(近郊区)快速增长、外圈层慢速增长、核心圈层(核心区)和外圈低速增长”,核心圈层的人口继续增长并向四周扩散,表明广州人口变动的郊区化现象明显,已呈现多中心特征,由2000年的“1个中心(人民公园)2个次中心(白云区的新景街和海珠区的凤阳街)”演变至2010年的“1个中心(人民公园)4个次中心(白云区的同德街、海珠区的凤阳街、天河区的棠下街和沙河街)”,次中心的人口集聚功能逐渐增强,对城市人口分布影响逐渐增大。%This paper uses the tabulations from 2000 and 2010 Population Censuses of Guangzhou to investigate the city’s demographic distribution and spatial structure. Spatial analysis, monocentric and polycentric population density models are implemented as analytical tools. The results are as follows:(1) The population spatial dynamic distribution of Guangzhou is that“population of the inner suburb grows fast, while that of the outer suburb slower, and that of the core circle the slowest”. (2) The population of Guangzhou’s inner city keeps growing and it also spreads to the suburban areas. Guangzhou’s polycentric structure has been consolidated by the increment of its subcentres. In 2000 there were two subcentres (Xinjing Street in Baiyun District and Fengyang Street in Haizhu District) and in 2010 there were six (Tongde Street in Baiyun District, Fengyang Street in Haizhu District, Tangxia Street and Shahe Street in Tianhe District). The subcentres are able to attract more people and also affect population distribution more significantly.

  4. Study of relationship between soybean (Glycine max (L. Merr. planting spatial arrangements and velvetleaf (Abutilon theophrasti L. population dynamic

    Directory of Open Access Journals (Sweden)

    Hamid SALEHIAN

    2015-11-01

    Full Text Available The velvetleaf is an important annual weed in the Mazandaran  province, Iran. Seeds are the only way of propagation and  renewal of this weed. More  knowledge was gained regarding  soil seed bank and its seed production to improve the  management of the velvetleaf weed in the future. There is a  minimal information concerning the impact of the soybean  planting pattern on the dynamics of the velvetleaf population.  For this reason two different fiel ds have been studied with the  cooperation of the Agriculture Discipline of the Islamic Azad  University, in Qaemshahr, Iran, during 2009 and 2012. In this  study the effect of two types of soybean row spacing were  used, 50 cm-wide and 36 cm - narrow, and three emergences  of the velvetleaf weed populatio n (periods 0-10, 10-20 and 20- 30 days after soybean sowing were implemented were  studied. Seed production, leaf area and dry matter increased in  each plant population of the velvetleaf weed in the 50-cm  soybean rows. Mortality rates we re decreased in velvetleaf’s  seedling population in the wider spaced rows. By observation  it was seen an increased producti on of seeds in the first batch  of seedlings. It appears that we must remove the first weed  emergence flushes within three to four weeks after the  soybean emergence to prevent reduced yields in the soybean  crop and further increase of the velvetleaf seed bank.   

  5. Spatial heterogeneity of cyanobacterial communities and genetic variation of Microcystis populations within large, shallow eutrophic lakes (Lake Taihu and Lake Chaohu, China)

    Institute of Scientific and Technical Information of China (English)

    Yuanfeng Cai; Fanxiang Kong; Limei Shi; Yang Yu

    2012-01-01

    Cyanobacteria,specifically Microcystis,usually form massive blooms in eutrophic freshwater lakes.Cyanobacterial samples were collected from eight sites of both Lake Taihu and Lake Chaohu in late summer to determine the diversity and distribution pattern of cyanobacteria and Microcystis in large,shallow,entropic lakes with significant spatial heterogeneity and long-term Microcystis bloom.Molecular methods based on denaturing gradient gel electrophoresis and clone library analysis were used.A similar heterogeneous distribution pattern of cyanobacteria in both lakes was observed.Most parts of these two lakes with high trophic level were dominated by Microcystis.However,in the regions with low trophic levels as well as low concentrations of chlorophyll a,Synechococcus occupied a considerable percentage.Different morphospecies and genotypes dominated the bloom-forming Microcystis populations in these two lakes.Microcystis viridis and Microcystis novacekii were dominant in Lake Chaohu,whereas Microcystis flos-aquae was dominant in Lake Taihu.Only 2 of thel3 Microcystis operational taxonomic units were shared between these two lakes.Analysis of molecular variance based on 16S to 23S internal transcribed spacer sequences indicated the significant genetic differentiation of Microcystis between these two lakes (Fst =0.19,p < 0.001).However,only 19.46% of the genetic variability was explained by the population variation between lakes,whereas most (80.54%) of the genetic variability occurred within the lakes.Phylogenetic analysis revealed no phylogeographic structure of Microcystis population in these two lakes,as illustrated by their cosmopolitan nature.Our results revealed that spatial heterogeneity within lakes has more impact on the cyanobacterial diversity than geographical isolation in a local scale.

  6. Population-level consequences of spatially heterogeneous exposure to heavy metals in soil: An individual-based model of springtails

    DEFF Research Database (Denmark)

    Meli, Mattia; Auclerc, Apolline; Palmqvist, Annemette;

    2013-01-01

    species for ecotoxicological risk assessment. In the model, individuals were assumed to sense and avoid contaminated habitat with a certain probability that depends on contamination level. Avoidance of contaminated areas thus influenced the individuals’ movement and feeding, their exposure, and in turn...... all other biological processes underlying population dynamics. Model rules and parameters were based on data from the literature, or were determined via pattern-oriented modelling. The model correctly predicted several patterns that were not used for model design and calibration. Simulation results...

  7. Understanding the recent colonization history of a plant pathogenic fungus using population genetic tools and Approximate Bayesian Computation.

    Science.gov (United States)

    Barrès, B; Carlier, J; Seguin, M; Fenouillet, C; Cilas, C; Ravigné, V

    2012-11-01

    Understanding the processes by which new diseases are introduced in previously healthy areas is of major interest in elaborating prevention and management policies, as well as in understanding the dynamics of pathogen diversity at large spatial scale. In this study, we aimed to decipher the dispersal processes that have led to the emergence of the plant pathogenic fungus Microcyclus ulei, which is responsible for the South American Leaf Blight (SALB). This fungus has devastated rubber tree plantations across Latin America since the beginning of the twentieth century. As only imprecise historical information is available, the study of population evolutionary history based on population genetics appeared most appropriate. The distribution of genetic diversity in a continental sampling of four countries (Brazil, Ecuador, Guatemala and French Guiana) was studied using a set of 16 microsatellite markers developed specifically for this purpose. A very strong genetic structure was found (F(st)=0.70), demonstrating that there has been no regular gene flow between Latin American M. ulei populations. Strong bottlenecks probably occurred at the foundation of each population. The most likely scenario of colonization identified by the Approximate Bayesian Computation (ABC) method implemented in DIYABC suggested two independent sources from the Amazonian endemic area. The Brazilian, Ecuadorian and Guatemalan populations might stem from serial introductions through human-mediated movement of infected plant material from an unsampled source population, whereas the French Guiana population seems to have arisen from an independent colonization event through spore dispersal. PMID:22828899

  8. Analysing the effect of movement on local survival: a new method with an application to a spatially structured population of the arboreal gecko Gehyra variegata.

    Science.gov (United States)

    Gruber, Bernd; Henle, Klaus

    2008-01-01

    Mortality during movement between habitat patches is the most obvious cost of dispersal, but rarely it has been demonstrated empirically. An approach is presented, which uses capture-mark-recapture data of an arboreal gecko species to determine the effect of individual movement on local survival in a spatially structured population. Because capture-mark-recapture data are widely available for a range of animal species, it should be possible to extend their application to other species. The method is based on the assumption that the tendency to be a territorial animal or to be a floating animal is fixed during the study period. The advantage of our approach is that only one additional parameter has to be estimated for describing movement risks. We further tested the power of our approach to detect an association of movement and mortality with simulated capture histories. The study revealed a strong negative effect of movement on local survival. Hence, animals that moved more often between trees had a lower survival rate. Interestingly, the mean movement rate for males was significantly higher than for females, which should lead to a biased sex ratio towards females in the population. As there was an even sex ratio in the population, we discuss not mutually exclusive explanations for this finding like differences in emigration rates between sexes, differences in survival rates between sexes, or a skewed sex ratio in offspring. PMID:17938971

  9. Spatial and temporal assessment of the initial pattern of phytoplankton population in a newly built coastal reservoir

    Science.gov (United States)

    Ren, Xiangyu; Yang, Kai; Che, Yue; Wang, Mingwei; Zhou, Lili; Chen, Liqiao

    2016-01-01

    For decades, the main threat to the water security of a metropolis, such as the city of Shanghai, has been the rapidly growing demand for water and at the same time, the decrease in water quality, including eutrophication. Therefore Shanghai shifted the preferred freshwater source to the Yangtze Estuary and constructed the Qingcaosha Reservoir, which is subject to less eutrophic water from the Yangtze River. To assess the population of phytoplankton for the first time in the newly built reservoir, this study improved an integrated method to assess the phytoplankton pattern in large-water-area reservoirs and lakes, using partial triadic analysis and Geographic Information Systems. Monthly sampling and monitoring from 10 stations in the reservoir from July 2010 to December 2011 were conducted. The study examined the common pattern of the phytoplankton population structure and determined the differences in the specific composition of the phytoplankton community during the transition period of the reservoir. The results suggest that in all but three sampling stations in the upper parts of Qingcaosha Reservoir, there was a strong common compromise in 2011. The two most important periods occurred from late summer to autumn and from winter to early spring. The former was characterized by the dominance of cyanobacteria, whereas the latter was characterized by the dominance of both chlorophyta and diatoms. Cyanobacteria (Microcystis spp. as the main genus) were the monopolistic dominant species in the summer after reservoir operation. The statistical analysis also indicated the necessity for regular monitoring to focus on the stations in the lower parts of the reservoir and on several limited species.

  10. Asymmetric dispersal and colonization success of Amazonian plant-ants queens.

    Directory of Open Access Journals (Sweden)

    Emilio M Bruna

    Full Text Available BACKGROUND: The dispersal ability of queens is central to understanding ant life-history evolution, and plays a fundamental role in ant population and community dynamics, the maintenance of genetic diversity, and the spread of invasive ants. In tropical ecosystems, species from over 40 genera of ants establish colonies in the stems, hollow thorns, or leaf pouches of specialized plants. However, little is known about the relative dispersal ability of queens competing for access to the same host plants. METHODOLOGY/PRINCIPAL FINDINGS: We used empirical data and inverse modeling--a technique developed by plant ecologists to model seed dispersal--to quantify and compare the dispersal kernels of queens from three Amazonian ant species that compete for access to host-plants. We found that the modal colonization distance of queens varied 8-fold, with the generalist ant species (Crematogaster laevis having a greater modal distance than two specialists (Pheidole minutula, Azteca sp. that use the same host-plants. However, our results also suggest that queens of Azteca sp. have maximal distances that are four-sixteen times greater than those of its competitors. CONCLUSIONS/SIGNIFICANCE: We found large differences between ant species in both the modal and maximal distance ant queens disperse to find vacant seedlings used to found new colonies. These differences could result from interspecific differences in queen body size, and hence wing musculature, or because queens differ in their ability to identify potential host plants while in flight. Our results provide support for one of the necessary conditions underlying several of the hypothesized mechanisms promoting coexistence in tropical plant-ants. They also suggest that for some ant species limited dispersal capability could pose a significant barrier to the rescue of populations in isolated forest fragments. Finally, we demonstrate that inverse models parameterized with field data are an excellent means

  11. Summarizing Spatial Distribution Density, Movement Patterns and Food Resources to Study the Impacts of Logging and Forest Conversion on Orang-utan Population

    Directory of Open Access Journals (Sweden)

    Raymond Alfred

    2010-01-01

    Full Text Available Problem statement: Orang-utan is classified as a totally protected species and is listed as an endangered species in Borneo. The survival of this species is highly dependent on the existence and quality of the lowland forest of Sabah. However, most of the pristine habitats in the lowland area have been converted into other land use activities such as a large scale plantation. This is due to the fact that most of the lowland forests are facing a continuous degradation process that will decrease its commercial value when it comes to generating revenue to the state government. Thus, the efforts to restore the forest are very vital. The main objectives of this study include establishing the relative spatial distribution of orang-utan in order to assess and determine the effects of the forest conversions in four main wild orang-utan population landscape, demonstrating the orang-utan population movement pattern as a response to the heavy logging activities and also quantifying the effect of logging activities on the status of food trees or plant species for orang-utan in their current forest habitat. Approach: In this research, relevant features are constructed in order to study the impacts of logging and forest conversion on Orang-utan population in Borneo. These features include aerial surveys and feeding behaviors. An aerial survey on orang-utan’s nest in four out of six main forest habitats for orang-utan in Sabah has been conducted between May 2005 and June 2009 in order to map the relative distribution and spatial density of the orang-utans. This is conducted in order to determine the impacts of the forest conversion for the last 20 years upon the orang-utan spatial distribution. In this project, three series of aerial surveys, covering Malua Forest Reserve, have been conducted to demonstrate the dynamic movement and habitat utilization by the orang-utan population, due to the logging activities within the forest habitat. A long term

  12. A Miocene hyperdiverse crocodylian community reveals peculiar trophic dynamics in proto-Amazonian mega-wetlands.

    Science.gov (United States)

    Salas-Gismondi, Rodolfo; Flynn, John J; Baby, Patrice; Tejada-Lara, Julia V; Wesselingh, Frank P; Antoine, Pierre-Olivier

    2015-04-01

    Amazonia contains one of the world's richest biotas, but origins of this diversity remain obscure. Onset of the Amazon River drainage at approximately 10.5 Ma represented a major shift in Neotropical ecosystems, and proto-Amazonian biotas just prior to this pivotal episode are integral to understanding origins of Amazonian biodiversity, yet vertebrate fossil evidence is extraordinarily rare. Two new species-rich bonebeds from late Middle Miocene proto-Amazonian deposits of northeastern Peru document the same hyperdiverse assemblage of seven co-occurring crocodylian species. Besides the large-bodied Purussaurus and Mourasuchus, all other crocodylians are new taxa, including a stem caiman-Gnatusuchus pebasensis-bearing a massive shovel-shaped mandible, procumbent anterior and globular posterior teeth, and a mammal-like diastema. This unusual species is an extreme exemplar of a radiation of small caimans with crushing dentitions recording peculiar feeding strategies correlated with a peak in proto-Amazonian molluscan diversity and abundance. These faunas evolved within dysoxic marshes and swamps of the long-lived Pebas Mega-Wetland System and declined with inception of the transcontinental Amazon drainage, favouring diversification of longirostrine crocodylians and more modern generalist-feeding caimans. The rise and demise of distinctive, highly productive aquatic ecosystems substantially influenced evolution of Amazonian biodiversity hotspots of crocodylians and other organisms throughout the Neogene. PMID:25716785

  13. Atlantic forcing of Amazonian climates in the last ice age

    Science.gov (United States)

    Bush, M. B.; Mosblech, N.; Valencia, B. G.; Hodell, D. A.; Gosling, W. D.; Van Calsteren, P. W.; Thomas, L. E.; Curtis, J. H.

    2011-12-01

    An absence of study sites means that the relative influence of orbitally driven presession cycles and millenial scale variability upon ice-age Amazonian precipitation is unknown. Here we present a continuous isotopic (δO18 and C13) record spanning the period from ~93-8 ka, from the aseasonal forests of Amazonian Ecuador. The variability in δO18 depletion is probably related to the relative strength of evapotranspired moisture (less depleted) and tropical Atlantic moisture carried across the basin by the South American Low Level Jet (more depleted). Times of strengthened South American Low Level Jet probably correspond to increased overall moisture availability and hence elevated precipitation. The occurrence of markedly depleted δO18 signatures during Heinrich events suggests a strong influence of the Atlantic Ocean on this system, and that these northern hemispheric stadials induced wet episodes in western Amazonia. Weakening of the Atlantic Meridional Overturning Circulation (AMOC) has been suggested to strengthen the South American Low Level Jet. The isotopic records reveal strong cohesion with previously published records from southern Brazil. A precessional influence amplifies the north Atlantic signal between c. 93 ka and 50 ka. However, after c. 50 ka the precessional signal weakens, perhaps sugesting that at a critical size the Laurentide ice mass exerted a strong influence on Neotropical climates suppressing the weaker forcing associated with precession. Contrary to long-standing expectation, the Last Glacial Maximum (21 ± 2 ka) does not stand out as time of aridity in this record. However, between c. 35 ka and 18 ka there is a drift toward less depleted rainfall. One hypothesis to account for this observation is that the climate was becoming more seasonal as the Intertropical Convergence Zone (ITCZ) formed further south than its modern location. The resulting weakened influence of the South American Summer Monsoon (SASM) would probably reduce wet

  14. Automated crown detection algorithm: an analysis of two tropical Amazonian forests

    Science.gov (United States)

    Palace, M.; Keller, M.; Asner, G.; Hagen, S.; Braswell, B.

    2002-12-01

    Spatial analysis of crowns in high-resolution images can improve the estimate of carbon stocks on regional and local scales, aid in demographic studies on the stand level, begin to analyze tree structural properties at the landscape level, and aid in forestry efforts. Radiative inverse transfer models, gap models, and cohort models may be parameterized with the spatial analysis of crowns and subsequently derived forest structural characteristics. We developed an algorithm to automatically detect tree crowns in two tropical Amazonian forests. IKONOS panchromatic images were used from two Amazonian forests in Para, Brazil: the Tapajos National Forest, (3.08° S, 54.94° W) and the Fazenda Cauaxi, (3.75° S, 48.37° W). Analysis was conducted on undisturbed forests from both sites. Our method combines local maximum filtering and local minima value finding methods with analysis of extracted transect data from the local maxima. We use a derivative threshold that ends the transect. Once all pixels of a given brightness value are analyzed, an iterative step examines the next lower brightness value. Pixels where crowns have been delineated are taken out of further analysis. Our method allows for overlap of crowns, gaps between crowns, and complex and noisy canopies to be analyzed. A sensitivity analysis was run on the derivative threshold and the minimum local maximum value to seed the transect analysis. Least-squares goodness of fit is conducted to examine parameterization from the sensitivity analysis. The best fit for the derivative threshold is found set at -8. The sensitivity analysis finds that the minimum local maxima is related to the difference between the maximum brightness value and brightness value with the highest frequency. Mean, minimum and maximum crown widths for field data are (mean 9.0 m +/- 1.6 S.D., min 1.0 m, max 40.7 m) and automated estimation are (mean 11.9 m +/- 5.0 S.D., min 2.0 m, max 34.0 m). The Kolmogorov-Smirov test for difference between

  15. Genetic divergence is more tightly related to call variation than landscape features in the Amazonian frogs Physalaemus petersi and P. freibergi.

    Science.gov (United States)

    Funk, W C; Cannatella, D C; Ryan, M J

    2009-09-01

    Behavioural isolation from divergence in male advertisement calls and female preferences is hypothesized to cause genetic divergence and speciation in the Amazonian frogs Physalaemus petersi and P. freibergi, yet the importance of call variation and landscape features in genetic divergence is unresolved. We tested for correlations between genetic divergence at microsatellite loci and (1) call variables; and (2) landscape variables among 10 populations of these frogs. Genetic divergence was not correlated with geographical distance, rivers or elevation. There was a strong positive relationship, however, between genetic divergence and inter-population differences in one call variable, whine dominant frequency. Effective population sizes varied among sites (range = 15-846) and were often small, suggesting that genetic drift could influence call evolution. Evidence for fine-scale genetic structure within sites was also found. Our results support the hypothesis that behavioural isolation from divergence in male calls and female preferences causes genetic divergence and speciation. PMID:19583696

  16. Ground-Vegetation Clutter Affects Phyllostomid Bat Assemblage Structure in Lowland Amazonian Forest.

    Science.gov (United States)

    Marciente, Rodrigo; Bobrowiec, Paulo Estefano D; Magnusson, William E

    2015-01-01

    Vegetation clutter is a limiting factor for bats that forage near ground level, and may determine the distribution of species and guilds. However, many studies that evaluated the effects of vegetation clutter on bats have used qualitative descriptions rather than direct measurements of vegetation density. Moreover, few studies have evaluated the effect of vegetation clutter on a regional scale. Here, we evaluate the influence of the physical obstruction of vegetation on phyllostomid-bat assemblages along a 520 km transect in continuous Amazonian forest. We sampled bats using mist nets in eight localities during 80 nights (3840 net-hours) and estimated the ground-vegetation density with digital photographs. The total number of species, number of animalivorous species, total number of frugivorous species, number of understory frugivorous species, and abundance of canopy frugivorous bats were negatively associated with vegetation clutter. The bat assemblages showed a nested structure in relation to degree of clutter, with animalivorous and understory frugivorous bats distributed throughout the vegetation-clutter gradient, while canopy frugivores were restricted to sites with more open vegetation. The species distribution along the gradient of vegetation clutter was not closely associated with wing morphology, but aspect ratio and wing load differed between frugivores and animalivores. Vegetation structure plays an important role in structuring assemblages of the bats at the regional scale by increasing beta diversity between sites. Differences in foraging strategy and diet of the guilds seem to have contributed more to the spatial distribution of bats than the wing characteristics of the species alone. PMID:26066654

  17. Ground-Vegetation Clutter Affects Phyllostomid Bat Assemblage Structure in Lowland Amazonian Forest.

    Directory of Open Access Journals (Sweden)

    Rodrigo Marciente

    Full Text Available Vegetation clutter is a limiting factor for bats that forage near ground level, and may determine the distribution of species and guilds. However, many studies that evaluated the effects of vegetation clutter on bats have used qualitative descriptions rather than direct measurements of vegetation density. Moreover, few studies have evaluated the effect of vegetation clutter on a regional scale. Here, we evaluate the influence of the physical obstruction of vegetation on phyllostomid-bat assemblages along a 520 km transect in continuous Amazonian forest. We sampled bats using mist nets in eight localities during 80 nights (3840 net-hours and estimated the ground-vegetation density with digital photographs. The total number of species, number of animalivorous species, total number of frugivorous species, number of understory frugivorous species, and abundance of canopy frugivorous bats were negatively associated with vegetation clutter. The bat assemblages showed a nested structure in relation to degree of clutter, with animalivorous and understory frugivorous bats distributed throughout the vegetation-clutter gradient, while canopy frugivores were restricted to sites with more open vegetation. The species distribution along the gradient of vegetation clutter was not closely associated with wing morphology, but aspect ratio and wing load differed between frugivores and animalivores. Vegetation structure plays an important role in structuring assemblages of the bats at the regional scale by increasing beta diversity between sites. Differences in foraging strategy and diet of the guilds seem to have contributed more to the spatial distribution of bats than the wing characteristics of the species alone.

  18. Amazonian Triatomine Biodiversity and the Transmission of Chagas Disease in French Guiana: In Medio Stat Sanitas.

    Science.gov (United States)

    Péneau, Julie; Nguyen, Anne; Flores-Ferrer, Alheli; Blanchet, Denis; Gourbière, Sébastien

    2016-02-01

    The effects of biodiversity on the transmission of infectious diseases now stand as a cornerstone of many public health policies. The upper Amazonia and Guyana shield are hot-spots of biodiversity that offer genuine opportunities to explore the relationship between the risk of transmission of Chagas disease and the diversity of its triatomine vectors. Over 730 triatomines were light-trapped in four geomorphological landscapes shaping French-Guiana, and we determined their taxonomic status and infection by Trypanosoma cruzi. We used a model selection approach to unravel the spatial and temporal variations in species abundance, diversity and infection. The vector community in French-Guiana is typically made of one key species (Panstrongylus geniculatus) that is more abundant than three secondary species combined (Rhodnius pictipes, Panstrongylus lignarius and Eratyrus mucronatus), and four other species that complete the assemblage. Although the overall abundance of adult triatomines does not vary across French-Guiana, their diversity increases along a coastal-inland gradient. These variations unravelled a non-monotonic relationship between vector biodiversity and the risk of transmission of Chagas disease, so that intermediate biodiversity levels are associated with the lowest risks. We also observed biannual variations in triatomine abundance, representing the first report of a biannual pattern in the risk of Chagas disease transmission. Those variations were highly and negatively correlated with the average monthly rainfall. We discuss the implications of these patterns for the transmission of T. cruzi by assemblages of triatomine species, and for the dual challenge of controlling Amazonian vector communities that are made of both highly diverse and mostly intrusive species. PMID:26867025

  19. Amazonian Triatomine Biodiversity and the Transmission of Chagas Disease in French Guiana: In Medio Stat Sanitas.

    Directory of Open Access Journals (Sweden)

    Julie Péneau

    2016-02-01

    Full Text Available The effects of biodiversity on the transmission of infectious diseases now stand as a cornerstone of many public health policies. The upper Amazonia and Guyana shield are hot-spots of biodiversity that offer genuine opportunities to explore the relationship between the risk of transmission of Chagas disease and the diversity of its triatomine vectors. Over 730 triatomines were light-trapped in four geomorphological landscapes shaping French-Guiana, and we determined their taxonomic status and infection by Trypanosoma cruzi. We used a model selection approach to unravel the spatial and temporal variations in species abundance, diversity and infection. The vector community in French-Guiana is typically made of one key species (Panstrongylus geniculatus that is more abundant than three secondary species combined (Rhodnius pictipes, Panstrongylus lignarius and Eratyrus mucronatus, and four other species that complete the assemblage. Although the overall abundance of adult triatomines does not vary across French-Guiana, their diversity increases along a coastal-inland gradient. These variations unravelled a non-monotonic relationship between vector biodiversity and the risk of transmission of Chagas disease, so that intermediate biodiversity levels are associated with the lowest risks. We also observed biannual variations in triatomine abundance, representing the first report of a biannual pattern in the risk of Chagas disease transmission. Those variations were highly and negatively correlated with the average monthly rainfall. We discuss the implications of these patterns for the transmission of T. cruzi by assemblages of triatomine species, and for the dual challenge of controlling Amazonian vector communities that are made of both highly diverse and mostly intrusive species.

  20. Investigating Late Amazonian Volcanotectonic Activity on Olympus Mons, Mars using Flank Vents and Arcuate Graben

    Science.gov (United States)

    Peters, S.; Christensen, P. R.

    2015-12-01

    Volcanism, a fundamental process in shaping the Martian surface, is crucial to understanding its evolution. Olympus Mons, the largest volcano on Mars, is one of several large shield volcanoes. Previous studies were technologically limited to large features associated with these constructs. With the advent of high resolution datasets, we are now able to investigate smaller features, such as flank vents and arcuate graben. Flank vents, common on polygenetic volcanoes, indicate that magma has propagated away from the main conduit and/or magma chamber. Vent morphology allows for the characterization of magma properties and eruption rates. Graben indicate extensional deformation. The distribution of graben provides information on stresses that acted on the volcano. In lieu of geophysical, spectral and in-situ data, morphology, morphometry and spatial relationships are powerful tools. We utilized high resolution image data (CTX, HiRISE and THEMIS IR) and topographic data (HRSC DTM, MOLA) to identify and characterize flank vents and graben. We observed 60 flank vents and 84 arcuate graben on Olympus Mons. Flank vents display varying morphologies and morphometries, suggesting different eruption styles and variable magma volatility. Vents occur primarily on the lower flank. This suggests magma has propagated substantial distances from the magma chamber. Observed clustering of vents may also indicate shallow magma sources. Similarly, graben are observed on the lower flank crosscutting young lava flows that have mantled portions of the escarpment. This indicates either gravitational spreading of Olympus Mons or flexure of the lithosphere in response to the load of the edifice. Collectively, the distribution of flank vents and arcuate graben suggests a similar development to that proposed for Ascraeus Mons. Based on superposition relationships and dates from previous studies, the flank vents and graben formed in the Late Amazonian (≤500 Ma).

  1. Disease and disaster: Optimal deployment of epidemic control facilities in a spatially heterogeneous population with changing behaviour.

    Science.gov (United States)

    Gaythorpe, Katy; Adams, Ben

    2016-05-21

    Epidemics of water-borne infections often follow natural disasters and extreme weather events that disrupt water management processes. The impact of such epidemics may be reduced by deployment of transmission control facilities such as clinics or decontamination plants. Here we use a relatively simple mathematical model to examine how demographic and environmental heterogeneities, population behaviour, and behavioural change in response to the provision of facilities, combine to determine the optimal configurations of limited numbers of facilities to reduce epidemic size, and endemic prevalence. We show that, if the presence of control facilities does not affect behaviour, a good general rule for responsive deployment to minimise epidemic size is to place them in exactly the locations where they will directly benefit the most people. However, if infected people change their behaviour to seek out treatment then the deployment of facilities offering treatment can lead to complex effects that are difficult to foresee. So careful mathematical analysis is the only way to get a handle on the optimal deployment. Behavioural changes in response to control facilities can also lead to critical facility numbers at which there is a radical change in the optimal configuration. So sequential improvement of a control strategy by adding facilities to an existing optimal configuration does not always produce another optimal configuration. We also show that the pre-emptive deployment of control facilities has conflicting effects. The configurations that minimise endemic prevalence are very different to those that minimise epidemic size. So cost-benefit analysis of strategies to manage endemic prevalence must factor in the frequency of extreme weather events and natural disasters. PMID:26992574

  2. Pesticide use and biodiversity conservation in the Amazonian agricultural frontier.

    Science.gov (United States)

    Schiesari, Luis; Waichman, Andrea; Brock, Theo; Adams, Cristina; Grillitsch, Britta

    2013-06-01

    Agricultural frontiers are dynamic environments characterized by the conversion of native habitats to agriculture. Because they are currently concentrated in diverse tropical habitats, agricultural frontiers are areas where the largest number of species is exposed to hazardous land management practices, including pesticide use. Focusing on the Amazonian frontier, we show that producers have varying access to resources, knowledge, control and reward mechanisms to improve land management practices. With poor education and no technical support, pesticide use by smallholders sharply deviated from agronomical recommendations, tending to overutilization of hazardous compounds. By contrast, with higher levels of technical expertise and resources, and aiming at more restrictive markets, large-scale producers adhered more closely to technical recommendations and even voluntarily replaced more hazardous compounds. However, the ecological footprint increased significantly over time because of increased dosage or because formulations that are less toxic to humans may be more toxic to other biodiversity. Frontier regions appear to be unique in terms of the conflicts between production and conservation, and the necessary pesticide risk management and risk reduction can only be achieved through responsibility-sharing by diverse stakeholders, including governmental and intergovernmental organizations, NGOs, financial institutions, pesticide and agricultural industries, producers, academia and consumers. PMID:23610177

  3. Fungal Community Assembly in the Amazonian Dark Earth.

    Science.gov (United States)

    Lucheta, Adriano Reis; Cannavan, Fabiana de Souza; Roesch, Luiz Fernando Wurdig; Tsai, Siu Mui; Kuramae, Eiko Eurya

    2016-05-01

    Here, we compare the fungal community composition and diversity in Amazonian Dark Earth (ADE) and the respective non-anthropogenic origin adjacent (ADJ) soils from four different sites in Brazilian Central Amazon using pyrosequencing of 18S ribosomal RNA (rRNA) gene. Fungal community composition in ADE soils were more similar to each other than their ADJ soils, except for only one site. Phosphorus and aluminum saturation were the main soil chemical factors contributing to ADE and ADJ fungal community dissimilarities. Differences in fungal richness were not observed between ADE and ADJ soil pairs regarding to the most sites. In general, the most dominant subphyla present in the soils were Pezizomycotina, Agaricomycotina, and Mortierellomycotina. The most abundant operational taxonomic units (OTUs) in ADE showed similarities with the entomopathogenic fungus Cordyceps confragosa and the saprobes Fomitopsis pinicola, Acremonium vitellinum, and Mortierellaceae sp., whereas OTUs similar to Aspergillus niger, Lithothelium septemseptatum, Heliocephala gracillis, and Pestalosphaeria sp. were more abundant in ADJ soils. Differences in fungal community composition were associated to soil chemical factors in ADE (P, Ca, Zn, Mg, organic matter, sum of bases, and base saturation) and ADJ (Al, potential acidity, Al saturation, B, and Fe) soils. These results contribute to a deeper view of the fungi communities in ADE and open new perspectives for entomopathogenic fungi studies. PMID:26585119

  4. Poor prospects for avian biodiversity in Amazonian oil palm.

    Directory of Open Access Journals (Sweden)

    Alexander C Lees

    Full Text Available Expansion of oil palm plantations across the humid tropics has precipitated massive loss of tropical forest habitats and their associated speciose biotas. Oil palm plantation monocultures have been identified as an emerging threat to Amazonian biodiversity, but there are no quantitative studies exploring the impact of these plantations on the biome's biota. Understanding these impacts is extremely important given the rapid projected expansion of oil palm cultivation in the basin. Here we investigate the biodiversity value of oil palm plantations in comparison with other dominant regional land-uses in Eastern Amazonia. We carried out bird surveys in oil palm plantations of varying ages, primary and secondary forests, and cattle pastures. We found that oil palm plantations retained impoverished avian communities with a similar species composition to pastures and agrarian land-uses and did not offer habitat for most forest-associated species, including restricted range species and species of conservation concern. On the other hand, the forests that the oil palm companies are legally obliged to protect hosted a relatively species-rich community including several globally-threatened bird species. We consider oil palm to be no less detrimental to regional biodiversity than other agricultural land-uses and that political pressure exerted by large landowners to allow oil palm to count as a substitute for native forest vegetation in private landholdings with forest restoration deficits would have dire consequences for regional biodiversity.

  5. Biotransformations of terpenes by fungi from Amazonian citrus plants.

    Science.gov (United States)

    Moreno Rueda, Maria Gabriela; Guerrini, Alessandra; Giovannini, Pier Paolo; Medici, Alessandro; Grandini, Alessandro; Sacchetti, Gianni; Pedrini, Paola

    2013-10-01

    The biotransformations of (RS)-linalool (1), (S)-citronellal (2), and sabinene (3) with fungi isolated from the epicarp of fruits of Citrus genus of the Amazonian forest (i.e., C. limon, C. aurantifolia, C. aurantium, and C. paradisiaca) are reported. The more active strains have been characterized, and they belong to the genus Penicillium and Fusarium. Different biotransformation products have been obtained depending on fungi and substrates. (RS)-Linalool (1) afforded the (E)- and (Z)-furanlinalool oxides (7 and 8, resp.; 39 and 37% yield, resp.) with Fusarium sp. (1D2), 6-methylhept-5-en-2-one (4; 49%) with F. fujikuroi, and 1-methyl-1-(4-methypentyl)oxiranemethanol (6; 42%) with F. concentricum. (S)-Citronellal (2) gave (S)-citronellol (12; 36-76%) and (S)-citronellic acid (11; 5-43%) with Fusarium species, while diastereoisomeric p-menthane-3,8-diols 13 and 14 (20 and 50% yield, resp.) were obtained as main products with Penicillium paxilli. Finally, both Fusarium species and P. paxilli biotransformed sabinene (3) to give mainly 4-terpineol (19; 23-56%), and (Z)- and (E)-sabinene hydrates (17 (3-21%) and 18 (11-17%), resp.). PMID:24130034

  6. Mosquitoes of eastern Amazonian Ecuador: biodiversity, bionomics and barcodes

    Directory of Open Access Journals (Sweden)

    Yvonne-Marie Linton

    2013-01-01

    Full Text Available Two snapshot surveys to establish the diversity and ecological preferences of mosquitoes (Diptera: Culicidae in the terra firme primary rain forest surrounding the Tiputini Biodiversity Station in the UNESCO Yasuní Biosphere Reserve of eastern Amazonian Ecuador were carried out in November 1998 and May 1999. The mosquito fauna of this region is poorly known; the focus of this study was to obtain high quality link-reared specimens that could be used to unequivocally confirm species level diversity through integrated systematic study of all life stages and DNA sequences. A total of 2,284 specimens were preserved; 1,671 specimens were link-reared with associated immature exuviae, all but 108 of which are slide mounted. This study identified 68 unique taxa belonging to 17 genera and 27 subgenera. Of these, 12 are new to science and 37 comprise new country records. DNA barcodes [658-bp of the mtDNA cytochrome c oxidase ( COI I gene] are presented for 58 individuals representing 20 species and nine genera. DNA barcoding proved useful in uncovering and confirming new species and we advocate an integrated systematics approach to biodiversity studies in future. Associated bionomics of all species collected are discussed. An updated systematic checklist of the mosquitoes of Ecuador (n = 179 is presented for the first time in 60 years.

  7. Physicochemical characteristics of pollen collected by Amazonian stingless bees

    Directory of Open Access Journals (Sweden)

    Kemilla Sarmento Rebelo

    2016-05-01

    Full Text Available ABSTRACT: The purpose of this study was to determine the physicochemical characteristics of pollen collected by the Amazonian stingless bees Melipona seminigra and Melipona interrupta , in order to verify whether their characteristics meet the physicochemical requirements established by the Brazilian Technical Regulation for Identity and Quality of Bee Pollen. Physicochemical analyses were performed through official analytical methods. Results of pollen analyses collected by M. seminigra and M. interrupta were respectively as follows: moisture: 53.39 and 37.12%; protein: 37.63 and 24.00%; lipids: 10.81 and 6.47%; ash: 4.03 and 2.74%; crude fiber: 9.30 and 13.65%; carbohydrates: 25.66 and 44.27%; energy: 350.47 and 331.33kcal%; pH: 3.70 and 3.34; total solids: 46.60 and 62.87%, and water activity: 0.91 and 0.85. The percentages of moisture and pH in pollen collected by both studied bees are not in agreement with the Technical Regulation for bee pollen. Since some characteristics, which are inherent to the Melipona pollen, were not in conform to the current Regulation, we recommend that further studies should be conducted to better characterize it, and correct the Regulation, if necessary.

  8. Estimating greenhouse gas emissions from future Amazonian hydroelectric reservoirs

    Science.gov (United States)

    de Faria, Felipe A. M.; Jaramillo, Paulina; Sawakuchi, Henrique O.; Richey, Jeffrey E.; Barros, Nathan

    2015-12-01

    Brazil plans to meet the majority of its growing electricity demand with new hydropower plants located in the Amazon basin. However, large hydropower plants located in tropical forested regions may lead to significant carbon dioxide and methane emission. Currently, no predictive models exist to estimate the greenhouse gas emissions before the reservoir is built. This paper presents two different approaches to investigate the future carbon balance of eighteen new reservoirs in the Amazon. The first approach is based on a degradation model of flooded carbon stock, while the second approach is based on flux data measured in Amazonian rivers and reservoirs. The models rely on a Monte Carlo simulation framework to represent the balance of the greenhouse gases into the atmosphere that results when land and river are converted into a reservoir. Further, we investigate the role of the residence time/stratification in the carbon emissions estimate. Our results imply that two factors contribute to reducing overall emissions from these reservoirs: high energy densities reservoirs, i.e., the ratio between the installed capacity and flooded area, and vegetation clearing. While the models’ uncertainties are high, we show that a robust treatment of uncertainty can effectively indicate whether a reservoir in the Amazon will result in larger greenhouse gas emissions when compared to other electricity sources.

  9. Estimating greenhouse gas emissions from future Amazonian hydroelectric reservoirs

    International Nuclear Information System (INIS)

    Brazil plans to meet the majority of its growing electricity demand with new hydropower plants located in the Amazon basin. However, large hydropower plants located in tropical forested regions may lead to significant carbon dioxide and methane emission. Currently, no predictive models exist to estimate the greenhouse gas emissions before the reservoir is built. This paper presents two different approaches to investigate the future carbon balance of eighteen new reservoirs in the Amazon. The first approach is based on a degradation model of flooded carbon stock, while the second approach is based on flux data measured in Amazonian rivers and reservoirs. The models rely on a Monte Carlo simulation framework to represent the balance of the greenhouse gases into the atmosphere that results when land and river are converted into a reservoir. Further, we investigate the role of the residence time/stratification in the carbon emissions estimate. Our results imply that two factors contribute to reducing overall emissions from these reservoirs: high energy densities reservoirs, i.e., the ratio between the installed capacity and flooded area, and vegetation clearing. While the models’ uncertainties are high, we show that a robust treatment of uncertainty can effectively indicate whether a reservoir in the Amazon will result in larger greenhouse gas emissions when compared to other electricity sources. (letter)

  10. Oxidative mitigation of aquatic methane emissions in large Amazonian rivers.

    Science.gov (United States)

    Sawakuchi, Henrique O; Bastviken, David; Sawakuchi, André O; Ward, Nicholas D; Borges, Clovis D; Tsai, Siu M; Richey, Jeffrey E; Ballester, Maria Victoria R; Krusche, Alex V

    2016-03-01

    The flux of methane (CH4 ) from inland waters to the atmosphere has a profound impact on global atmospheric greenhouse gas (GHG) levels, and yet, strikingly little is known about the dynamics controlling sources and sinks of CH4 in the aquatic setting. Here, we examine the cycling and flux of CH4 in six large rivers in the Amazon basin, including the Amazon River. Based on stable isotopic mass balances of CH4 , inputs and outputs to the water column were estimated. We determined that ecosystem methane oxidation (MOX) reduced the diffusive flux of CH4 by approximately 28-96% and varied depending on hydrologic regime and general geochemical characteristics of tributaries of the Amazon River. For example, the relative amount of MOX was maximal during high water in black and white water rivers and minimal in clear water rivers during low water. The abundance of genetic markers for methane-oxidizing bacteria (pmoA) was positively correlated with enhanced signals of oxidation, providing independent support for the detected MOX patterns. The results indicate that MOX in large Amazonian rivers can consume from 0.45 to 2.07 Tg CH4 yr(-1) , representing up to 7% of the estimated global soil sink. Nevertheless, climate change and changes in hydrology, for example, due to construction of dams, can alter this balance, influencing CH4 emissions to atmosphere. PMID:26872424

  11. The impact of Amazonian deforestation on Amazon basin rainfall

    Science.gov (United States)

    Spracklen, D. V.; Garcia-Carreras, L.

    2015-11-01

    We completed a meta-analysis of regional and global climate model simulations (n = 96) of the impact of Amazonian deforestation on Amazon basin rainfall. Across all simulations, mean (±1σ) change in annual mean Amazon basin rainfall was -12 ± 11%. Variability in simulated rainfall was not explained by differences in model resolution or surface parameters. Across all simulations we find a negative linear relationship between rainfall and deforestation extent, although individual studies often simulate a nonlinear response. Using the linear relationship, we estimate that deforestation in 2010 has reduced annual mean rainfall across the Amazon basin by 1.8 ± 0.3%, less than the interannual variability in observed rainfall. This may explain why a reduction in Amazon rainfall has not consistently been observed. We estimate that business-as-usual deforestation (based on deforestation rates prior to 2004) would lead to an 8.1 ± 1.4% reduction in annual mean Amazon basin rainfall by 2050, greater than natural variability.

  12. Use of amazonian anthropogenic soils: Comparison between Caboclos communities and Tikunas indigenous group

    International Nuclear Information System (INIS)

    In general terms, Amazonian soils are infertile and have several constraints for agricultural production. However, use by ancient human societies since pre-columbian times has driven landscape transformation of massive areas and development of anthropogenic soils called Terra Preta do Indio (TP) or Amazonian Dark Earths (ADE). ADE characterization, in terms of fertility and composition, has allowed the development of intensive agricultural activities over time. The current use of ADE for the Brazilian amazon peasants (Caboclos) is different from the indigenous communities in Colombia. The indigenous people in Colombia (Tikunas) no use this type of soils on behalf of cultural restrictions that avoid the use of ancient places. We are comparing the institutional conditions, migrations, social characterization and cultural factors that determine the use/no-use of these soils by the Amazonian societies.

  13. Ocurrence of Cryptosporidium spp. in Amazonian manatees (Trichechus inunguis, Natterer, 1883

    Directory of Open Access Journals (Sweden)

    Maria Aparecida da Glória Faustino

    2007-09-01

    Full Text Available The apicomplexa protozoa Cryptosporidium infects several mammals, including terrestrial and aquatic species. In the epidemiology of this infection, the ingestion of water and/or food contamined with oocysts comprises the main mechanism of transmission to susceptible animals. Among the Sirenians, the occurrence of this coccidium has been reported in dugongs (Dugong dugon and Antillean manatee (Trichechus manatus manatus. The present study was conducted with the aim of verifying the occurrence of Cryptosporidium spp. in Amazonian manatee. For this purpose, fecal samples were collected from ten free-ranging Amazonian manatees, two specimens in captivity, and 103 supernatants fecal samples. The samples were processed by the sedimentation method in formol-ether and Kinyoun stain technique for the presence of Cryptosporidium spp.. The positive samples were then submitted to Direct Immunoflorescence Test. The results showed 4.34% (05/115 of positive samples. This is the first report of Cryptosporidium spp. in the Amazonian manatee.

  14. Amazonian and neotropical plant communities on glacial time-scales: The failure of the aridity and refuge hypotheses

    Science.gov (United States)

    Colinvaux, P. A.; De Oliveira, P. E.; Bush, M. B.

    2000-01-01

    Plants respond to Pleistocene climatic change as species, not as associations or biomes. This has been demonstrated unequivocally by paleobotanical data for temperate latitudes. In the far richer vegetations of the tropics species populations also fluctuated independently in response to climatic forcing, from their longlasting glacial states to the patterns of brief interglacials like the present and back again. We use pollen data to reconstruct the vegetation of the Amazon basin in oxygen isotope stages 3 and 2 of the last glaciation in order to measure how the plant populations of the Amazon responded to the global warming at the onset of the Holocene. We find that plant communities of the neotropics vent copious pollen to lake sediments and that this pollen yields powerful signals for community composition. Three continuous sedimentary records reaching through oxygen isotope stage 2 are available from the Amazon lowlands, those from Carajas, Lake Pata and marine deposits off the mouth of the Amazon River. All three records yield pollen histories of remarkable constancy and stability. By comparing them with deposits of equal antiquity from the cerrado (savanna) of central Brazil, we show that most of the Amazon lowlands remained under forest throughout a glacial cycle. This forest was never fragmented by open vegetation as postulated by the refugia hypothesis. Instead the intact forest of glacial times included significant populations of plants that are now montane, suggesting that the global warming of the early Holocene resulted in the expulsion of heat intolerant plants from the lowland forest. Pollen data from the Amazonian flank of the Andes and from Pacific Panama provide evidence that populations of these heat intolerant plants survive the heat of interglacials in part by maintaining large populations at cooler montane altitudes. Our conclusion that the Amazon lowlands were forested in glacial times specifically refutes the hypothesis of Amazonian glacial

  15. 苹果园镰螯螨种群的时空动态分析%Time-series and spatial dynamics of Tydeus population in apple tree gardens

    Institute of Scientific and Technical Information of China (English)

    崔晓宁; 沈慧敏; 郑开福; 张新虎

    2012-01-01

    The time-series dynamics and spatial pattern of Tydeus population in apple tree gardens with lower artificial interference were analyzed by calculating five indices of aggregation, and parameters of Iwao model according to practical surveys. The results showed that the number of population increased before August 1st and then gradually decreased from August to October. The peak occurred on August 1st. The spatial pattern of Tydeus in apple tree garden belonged to an aggregated distribution pattern, but the lower crown belonged to uniform distribution pattern. The population was distributed in individual colonies. Its aggregation intensity was kept in a certain level from July 1st to October 1st, and then increased in lower, east, north crowns from October 1st to the middle of October. Euseius flnlcmdicus, spider mites and Tydeus were inter-restricted and interdependent in the ecosystem of apple tree garden. Tydeus was main prey of E. Finlandicus when spider mite population decreased to a lower level. Tydeus played an important role in maintaining the number of E. Finlandicus population and biological diversity and dynamic balance of population number in apple tree garden.%根据田间实际调查结果,应用5种聚集度指标和Iwao法分析了镰螯螨在人为干扰因素较小的苹果园内种群的发生动态和空间格局.结果表明:7-10月,镰螯螨种群数量随着时间变化表现为先升高后降低的趋势,8月初达到发生高峰期.除树冠下层呈现均匀分布外,其他部位均呈现聚集分布,分布的基本成分是个体群.8月1日到10月1日,各部位间种群聚集度变化平稳;10月1日到10月16日,树冠下层、西面和北面的聚集度略有增高.在苹果园生态系统中,芬兰真绥螨、叶螨、镰螯螨三者不仅相互制约而且相互依存.当果园内叶螨种群数量随捕食螨的作用而降低到较低水平后,镰螯螨作为主要捕食螨—芬兰真绥螨的重要补充猎物,对于维持芬

  16. Enhanced vector borne disease surveillance of California Culex mosquito populations reveals spatial and species-specific barriers of infection.

    Energy Technology Data Exchange (ETDEWEB)

    VanderNoot, Victoria A.; Curtis, Deanna Joy; Koh, Chung-Yan; Brodsky, Benjamin H; Lane, Todd

    2014-08-01

    terium and c am p y l o bacter bac t er i al spec i e s . W e utilized the s e mic r obial transcri p tomes pre s e nt in g e ogra p hical l y defined Cul e x po p ul a tions to defi n e spatial and m osqui t o specie s -spec i fic ba r r iers of i n fecti o n. T he v i r ome and microbi o me c o mpos i tion id e ntified in e ach mosqui t o p o ol pr o v i ded suf f icient resolut i on to dete r m i ne both the mosq u ito species and the g e o graphic regi o n in Californ i a w h e re t h e mosqui t o po o l orig i n ated. T his d a ta pr o v i des ins i ght in t o the compl e x i t y of microb i al spec i es cir c ulati n g in med i cal l y i mport a nt Culex mosqui t oes a nd t h eir potent i al im p act o n t he tran s missi o n of v ector-b o rne human / veter i na r y p a t hogens in C a liforn i a.

  17. Paleodistributions and comparative molecular phylogeography of leafcutter ants (Atta spp. provide new insight into the origins of Amazonian diversity.

    Directory of Open Access Journals (Sweden)

    Scott E Solomon

    Full Text Available The evolutionary basis for high species diversity in tropical regions of the world remains unresolved. Much research has focused on the biogeography of speciation in the Amazon Basin, which harbors the greatest diversity of terrestrial life. The leading hypotheses on allopatric diversification of Amazonian taxa are the Pleistocene refugia, marine incursion, and riverine barrier hypotheses. Recent advances in the fields of phylogeography and species-distribution modeling permit a modern re-evaluation of these hypotheses. Our approach combines comparative, molecular phylogeographic analyses using mitochondrial DNA sequence data with paleodistribution modeling of species ranges at the last glacial maximum (LGM to test these hypotheses for three co-distributed species of leafcutter ants (Atta spp.. The cumulative results of all tests reject every prediction of the riverine barrier hypothesis, but are unable to reject several predictions of the Pleistocene refugia and marine incursion hypotheses. Coalescent dating analyses suggest that population structure formed recently (Pleistocene-Pliocene, but are unable to reject the possibility that Miocene events may be responsible for structuring populations in two of the three species examined. The available data therefore suggest that either marine incursions in the Miocene or climate changes during the Pleistocene--or both--have shaped the population structure of the three species examined. Our results also reconceptualize the traditional Pleistocene refugia hypothesis, and offer a novel framework for future research into the area.

  18. Eco-SpaCE: An object-oriented, spatially explicit model to assess the risk of multiple environmental stressors on terrestrial vertebrate populations

    International Nuclear Information System (INIS)

    Wildlife organisms are exposed to a combination of chemical, biological and physical stressors. Information about the relative impact of each stressor can support management decisions, e.g., by the allocation of resources to counteract those stressors that cause most harm. The present paper introduces Eco-SpaCE; a novel receptor-oriented cumulative exposure model for wildlife species that includes relevant ecological processes such as spatial habitat variation, food web relations, predation, and life history. A case study is presented in which the predicted mortality due to cadmium contamination is compared with the predicted mortality due to flooding, starvation, and predation for three small mammal species (Wood mouse, Common vole, and European mole) and a predator (Little owl) living in a lowland floodplain along the river Rhine in The Netherlands. Results indicated that cadmium is the principal stressor for European mole and Little owl populations. Wood mouse and Common vole population densities were mainly influenced by flooding and food availability. Their estimated population sizes were consistent with numbers reported in literature. Predictions for cadmium accumulation and flooding stress were in agreement with field data. The large uncertainty around cadmium toxicity for wildlife leads to the conclusion that more species-specific ecotoxicological data is required for more realistic risk assessments. The predictions for starvation were subject to the limited quantitative information on biomass obtainable as food for vertebrates. It is concluded that the modelling approach employed in Eco-SpaCE, combining ecology with ecotoxicology, provides a viable option to explore the relative contribution of contamination to the overall stress in an ecosystem. This can help environmental managers to prioritize management options, and to reduce local risks.

  19. Seasonal variation of serum biochemical values of Amazonian snakes (Boa constrictor constrictor) kept in captivity

    OpenAIRE

    Dennis José da Silva Lima; Renata Kelly Gonzaga Bastos; Larissa dos Santos Seixas; Monique Araújo Luz; Erika Renata Branco; Nazaré Fonseca de Souza; Carla Cristina Guimarães de Moraes; Andre Marcelo Conceição Meneses

    2012-01-01

    In northern Brazil, the seasons are not well defined compared to the South and Southeast regions, due to a hot and humid equatorial climate with a rainy season, known as the Amazonian winter, and a period with less rain, known as the Amazonian summer. The goal of this study was to evaluate the biochemical variation of serum from the Amazon Boa constrictor by correlating the values with the seasons of the region. A biochemical analysis of the serum was performed (AST, ALT, LDH, ALP, calcium, u...

  20. Indifference to dissonance in native Amazonians reveals cultural variation in music perception.

    Science.gov (United States)

    McDermott, Josh H; Schultz, Alan F; Undurraga, Eduardo A; Godoy, Ricardo A

    2016-07-28

    by biology remains debated. One widely discussed phenomenon is that some combinations of notes are perceived by Westerners as pleasant, or consonant, whereas others are perceived as unpleasant,or dissonant. The contrast between consonance and dissonance is central to Western music and its origins have fascinated scholars since the ancient Greeks. Aesthetic responses to consonance are commonly assumed by scientists to have biological roots, and thus to be universally present in humans. Ethnomusicologists and composers, in contrast, have argued that consonance is a creation of Western musical culture. The issue has remained unresolved, partly because little is known about the extent of cross-cultural variation in consonance preferences. Here we report experiments with the Tsimane'--a native Amazonian society with minimal exposure to Western culture--and comparison populations in Bolivia and the United States that varied in exposure to Western music. Participants rated the pleasantness of sounds. Despite exhibiting Western-like discrimination abilities and Western-like aesthetic responses to familiar sounds and acoustic roughness, the Tsimane' rated consonant and dissonant chords and vocal harmonies as equally pleasant. By contrast, Bolivian city- and town-dwellers exhibited significant preferences for consonance,albeit to a lesser degree than US residents. The results indicate that consonance preferences can be absent in cultures sufficiently isolated from Western music, and are thus unlikely to reflect innate biases or exposure to harmonic natural sounds. The observed variation in preferences is presumably determined by exposure to musical harmony, suggesting that culture has a dominant role in shaping aesthetic responses to music. PMID:27409816

  1. The impact of deforestation in the Amazonian atmospheric radiative balance: a remote sensing assessment

    Directory of Open Access Journals (Sweden)

    E. T. Sena

    2012-06-01

    Full Text Available This paper addresses the Amazonian radiative budget after considering three aspects of deforestation: (i the emission of aerosols from biomass burning due to forest fires; (ii changes in surface albedo after deforestation and (iii modifications in the column water vapour amount over deforested areas. Simultaneous Clouds and the Earth's Radiant Energy System (CERES shortwave fluxes and aerosol optical depth (AOD retrievals from the Moderate Resolution Imaging SpectroRadiometer (MODIS were analysed during the peak of the biomass burning seasons (August and September from 2000 to 2009. A discrete-ordinate radiative transfer (DISORT code was used to extend instantaneous remote sensing radiative forcing assessments into 24-h averages. The mean direct radiative forcing of aerosols at the top of the atmosphere (TOA during the biomass burning season for the 10-yr studied period was −5.6 ± 1.7 W m−2. Furthermore, the spatial distribution of the direct radiative forcing of aerosols over Amazon was obtained for the biomass burning season of each year. It was observed that for high AOD (larger than 1 at 550 nm the imbalance in the radiative forcing at the TOA may be as high as −20 W m−2 locally. The surface reflectance plays a major role in the aerosol direct radiative effect. The study of the effects of biomass burning aerosols over different surface types shows that the direct radiative forcing is systematically more negative over forest than over savannah-like covered areas. Values of −15.7 ± 2.4 W m−2550 nm and −9.3 ± 1.7 W m−2550 nm were calculated for the mean daily aerosol forcing efficiencies over forest and savannah-like vegetation respectively. The overall mean annual albedo-change radiative forcing due to deforestation over the state of Rondônia, Brazil, was determined as −7.3 ± 0.9 W m−2. Biomass burning aerosols impact the radiative

  2. Alluvial deposits and plant distribution in an Amazonian lowland megafan

    Science.gov (United States)

    Zani, H.; Rossetti, D.; Cremon; Cohen, M.; Pessenda, L. C.

    2012-12-01

    A large volume of sandy alluvial deposits (> 1000 km2) characterizes a flat wetland in northern Amazonia. These have been recently described as the sedimentary record of a megafan system, which have a distinct triangular shape produced by highly migratory distributary rivers. The vegetation map suggests that this megafan is dominated by open vegetation in sharp contact with the surround rainforest. Understanding the relationship between geomorphological processes and vegetation distribution is crucial to decipher and conserve the biodiversity in this Amazonian ecosystem. In this study we interpret plant dynamics over time, and investigate its potential control by sedimentary processes during landscape evolution. The study area is located in the Viruá National Park. Two field campaigns were undertaken in the dry seasons of 2010 and 2011 and the sampling sites were selected by combining accessibility and representativeness. Vegetation contrasts were recorded along a transect in the medial section of the Viruá megafan. Due to the absence of outcrops, samples were extracted using a core device, which allowed sampling up to a depth of 7.5 m. All cores were opened and described in the field, with 5 cm3 samples collected at 20 cm intervals. The δ13C of organic matter was used as a proxy to distinguish between C3 and C4 plant communities. The chronology was established based on radiocarbon dating. The results suggest that the cores from forested areas show the most depleted values of δ13C, ranging from -32.16 to -27.28‰. The δ13C curve in these areas displays typical C3 land plant values for the entire record, which covers most of the Holocene. This finding indicates that either the vegetation remained stable over time or the sites were dominated by aquatic environments with freshwater plants before forest establishment. The cores from the open vegetation areas show a progressive upward enrichment in δ13C values, which range from -28.50 to -19.59‰. This trend is

  3. Analysing Amazonian forest productivity using a new individual and trait-based model (TFS v.1)

    Science.gov (United States)

    Fyllas, N. M.; Gloor, E.; Mercado, L. M.; Sitch, S.; Quesada, C. A.; Domingues, T. F.; Galbraith, D. R.; Torre-Lezama, A.; Vilanova, E.; Ramírez-Angulo, H.; Higuchi, N.; Neill, D. A.; Silveira, M.; Ferreira, L.; Aymard C., G. A.; Malhi, Y.; Phillips, O. L.; Lloyd, J.

    2014-07-01

    Repeated long-term censuses have revealed large-scale spatial patterns in Amazon basin forest structure and dynamism, with some forests in the west of the basin having up to a twice as high rate of aboveground biomass production and tree recruitment as forests in the east. Possible causes for this variation could be the climatic and edaphic gradients across the basin and/or the spatial distribution of tree species composition. To help understand causes of this variation a new individual-based model of tropical forest growth, designed to take full advantage of the forest census data available from the Amazonian Forest Inventory Network (RAINFOR), has been developed. The model allows for within-stand variations in tree size distribution and key functional traits and between-stand differences in climate and soil physical and chemical properties. It runs at the stand level with four functional traits - leaf dry mass per area (Ma), leaf nitrogen (NL) and phosphorus (PL) content and wood density (DW) varying from tree to tree - in a way that replicates the observed continua found within each stand. We first applied the model to validate canopy-level water fluxes at three eddy covariance flux measurement sites. For all three sites the canopy-level water fluxes were adequately simulated. We then applied the model at seven plots, where intensive measurements of carbon allocation are available. Tree-by-tree multi-annual growth rates generally agreed well with observations for small trees, but with deviations identified for larger trees. At the stand level, simulations at 40 plots were used to explore the influence of climate and soil nutrient availability on the gross (ΠG) and net (ΠN) primary production rates as well as the carbon use efficiency (CU). Simulated ΠG, ΠN and CU were not associated with temperature. On the other hand, all three measures of stand level productivity were positively related to both mean annual precipitation and soil nutrient status

  4. Thresholds of species loss in Amazonian deforestation frontier landscapes.

    Science.gov (United States)

    Ochoa-Quintero, Jose Manuel; Gardner, Toby A; Rosa, Isabel; Ferraz, Silvio Frosini de Barros; Sutherland, William J

    2015-04-01

    In the Brazilian Amazon, private land accounts for the majority of remaining native vegetation. Understanding how land-use change affects the composition and distribution of biodiversity in farmlands is critical for improving conservation strategies in the face of rapid agricultural expansion. Working across an area exceeding 3 million ha in the southwestern state of Rondônia, we assessed how the extent and configuration of remnant forest in replicate 10,000-ha landscapes has affected the occurrence of a suite of Amazonian mammals and birds. In each of 31 landscapes, we used field sampling and semistructured interviews with landowners to determine the presence of 28 large and medium sized mammals and birds, as well as a further 7 understory birds. We then combined results of field surveys and interviews with a probabilistic model of deforestation. We found strong evidence for a threshold response of sampled biodiversity to landscape level forest cover; landscapes with deforested landscapes many species are susceptible to extirpation following relatively small additional reductions in forest area. In the model of deforestation by 2030 the number of 10,000-ha landscapes under a conservative threshold of 43% forest cover almost doubled, such that only 22% of landscapes would likely to be able to sustain at least 75% of the 35 focal species we sampled. Brazilian law requires rural property owners in the Amazon to retain 80% forest cover, although this is rarely achieved. Prioritizing efforts to ensure that entire landscapes, rather than individual farms, retain at least 50% forest cover may help safeguard native biodiversity in private forest reserves in the Amazon. PMID:25580947

  5. The Influence of Amazonian Deforestation under Varied Rainfall Regimes

    Science.gov (United States)

    Bagley, J. E.; Desai, A. R.; Harding, K. J.; Snyder, P. K.; Foley, J. A.

    2011-12-01

    In the past six years the Amazon basin has experienced two "once in a century" level droughts. The impacts of the 2005 and 2010 droughts ranged from large increases in fire frequency to a reversal of the Amazon region from a net carbon sink of ~.4 Pg C year-1 in normal years to a source of 1.8 Pg C year-1 for 2010. Coupled with impacts from deforestation in the region, these droughts strongly altered the services provided by local ecosystems including the biogeophysical regulation of energy and water flow between the land and the atmosphere. We investigated how the biogeophysical impacts of land cover change (LCC) in the Amazon Basin differ under drought versus pluvial conditions, and how the differences may enhance or diminish those conditions by altering precipitation patterns and intensity. In particular, we focus on how changes in evapotranspiration due to LCC influence both surface energy balance and local/downstream precipitation differently under varying rainfall regimes. We utilized a series of twelve simulations of the Weather Research and Forecasting (WRF) mesoscale atmospheric model coupled to the Noah land surface model to model the influence of deforestation on regional precipitation. These simulations represent three drought years (including 2005 and 2010) and three pluvial years, with land cover set as both potential and actual for each year. Using the precipitation backtrajectory approach of Dirmeyer and Brubaker (2007) we identify where evapotranspired moisture from the Amazon falls as precipitation during the region's dry season. This allows us to calculate how the dual influences of deforestation and natural variability alter the location, magnitude, and recycling ratio of rainfall originating from Amazonian evapotranspiration, all of which are key metrics for both ecological services and productivity in the region.

  6. Health and demography of native Amazonians: historical perspective and current status Saúde e demografia de povos indígenas amazônicos: perspectiva histórica e situação atual

    Directory of Open Access Journals (Sweden)

    Warren M. Hern

    1991-12-01

    Full Text Available Native Amazonians have been the victims of two massive historical assaults, one at the time of the Conquest and the other during the Twentieth century. Due to epidemic disease and environmental destruction, many tribes have gone from contact to displacement, decimation, and extinction in a single generation. Deculturation and the construction of large development projects have had catastrophic effects on native populations. In many ways, native Amazonians have experienced a reverse of the "Epidemiologic Transition". Paradoxically, one of the effects of cultural disruption for some native Amazonians has been the loss of cultural controls on fertility with the result that high fertility has become a major health problem. Combined with rapid growth of non-indigenous Amazonian populations, deforestation, and urbanization, native Amazonians face grave obstacles to long-term survival.Os nativos da Amazônia foram vítimas de dois grandes ataques históricos: um na época da Conquista e outro durante o século XX. Devido a doenças epidêmicas e à destruição ambiental, inúmeras tribos passaram a vivenciar problemas de deslocamentos, dizimação e extinção em uma única geração. A aculturação e a construção de grandes projetos desenvolvimentistas tiveram efeitos catastróficos sobre as populações indígenas. Em diversos aspectos, os nativos da Amazônia sofreram uma "Transição Epidemiológica". Paradoxalmente, um dos efeitos da dilaceração cultural para alguns dos nativos da Amazônia foi a perda de controles culturais sobre a fecundidade, fazendo com que a elevada fecundidade se tornasse um importante problema de saúde. Com o rápido crescimento de populações amazônicas não indígenas, o desmatamento e a urbanização, os nativos da Amazônia enfrentam sérios obstáculos para a sua sobrevivência a longo prazo.

  7. Development of population structure and spatial distribution patterns of a restored forest during 17-year succession (1993-2010) in Pingshuo opencast mine spoil, China.

    Science.gov (United States)

    Zhao, Zhongqiu; Wang, Lianhua; Bai, Zhongke; Pan, Ziguan; Wang, Yun

    2015-07-01

    Afforestation of native tree species is often recommended for ecological restoration in mining areas, but the understanding of the ecological processes of restored vegetation is quite limited. In order to provide insight of the ecological processes of restored vegetation, in this study, we investigate the development of the population structure and spatial distribution patterns of restored Robinia pseudoacacia (ROPS) and Pinus tabuliformis (PITA) mixed forests during the 17 years of the mine spoil period of the Pingshuo opencast mine, Shanxi Province, China. After a 17-year succession, apart from the two planted species, Ulmus pumila (ULPU), as an invasive species, settled in the plot along with a large number of small diameter at breast height (DBH) size. In total, there are 10,062 living individual plants, much more than that at the plantation (5105), and ROPS had become the dominant species with a section area with a breast height of 9.40 m(2) hm(-2) and a mean DBH of 6.72 cm, much higher than both PITA and ULPU. The DBH size classes of all the total species showed inverted J-shaped distributions, which may have been a result of the large number of small regenerated ULPU trees. The DBH size classes of both ROPS and PITA showed peak-type structures with individuals mainly gathering in the moderate DBH size class, indicating a relatively healthy DBH size class structure. Meanwhile, invasive ULPU were distributed in a clear L shape, concentrating on the small DBH size class, indicating a relatively low survival rate for adult trees. Both ROPS and PITA species survival in the plantation showed uniform and aggregated distribution at small scales and random with scales increasing. ULPU showed a strong aggregation at small scales as well as random with scales increasing. Both the population structure and spatial distribution indicated that ROPS dominates and will continue to dominate the community in the future succession, which should be continuously monitored

  8. 中国流动人口地域类型——划分方法及空间分布%The regional types of China's floating population: Identification methods and spatial patterns

    Institute of Scientific and Technical Information of China (English)

    刘盛和; 胡章; 邓羽; 王英杰

    2011-01-01

    With the rapid increase of the number and influence of floating population in China,it is urgently needed to understand the regional types of China's floating population and their spatial characteristics. After reviewing the current methods for identifying regional types of floating population, this paper puts forward a new composite-index identification method and its modification version which is consisted of two indexes of the net migration rate and gross migration rate. Then, the traditional single-index and the new composite-index identification methods are empirically tested to explore their spatial patterns and characteristics by using China's 2000 census data at county level. The results show: (1) The composite-index identification method is much better than traditional single-index method because it can measure the migration direction and scale of floating simultaneously, and in particular it can identify the unique regional types of floating population with large scale of immigration and emigration. (2)The modified composite-index identification method, by using the share of a region's certain type of floating population to the total in China as weights, can effectively correct the over- or under-estimated errors due to the rather large or small total population of a region. (3) The spatial patterns of different regional types of China's floating population are closely related to the regional differentiation of their natural environment, population density and socio-economic development level. The three active regional types of floating population are mainly located in the eastern part of China with lower elevation, more than 800 mm precipitation, rather higher population densities and economic development levels.

  9. Application of Spatial and Closed Capture-Recapture Models on Known Population of the Western Derby Eland (Taurotragus derbianus derbianus) in Senegal.

    Science.gov (United States)

    Jůnek, Tomáš; Jůnková Vymyslická, Pavla; Hozdecká, Kateřina; Hejcmanová, Pavla

    2015-01-01

    Camera trapping with capture-recapture analyses has provided estimates of the abundances of elusive species over the last two decades. Closed capture-recapture models (CR) based on the recognition of individuals and incorporating natural heterogeneity in capture probabilities are considered robust tools; however, closure assumption is often questionable and the use of an Mh jackknife estimator may fail in estimations of real abundance when the heterogeneity is high and data is sparse. A novel, spatially explicit capture-recapture (SECR) approach based on the location-specific capture histories of individuals overcomes the limitations of closed models. We applied both methods on a closed population of 16 critically endangered Western Derby elands in the fenced 1,060-ha Fathala reserve, Senegal. We analyzed the data from 30 cameras operating during a 66-day sampling period deployed in two densities in grid and line arrays. We captured and identified all 16 individuals in 962 trap-days. Abundances were estimated in the programs CAPTURE (models M0, Mh and Mh Chao) and R, package secr (basic Null and Finite mixture models), and compared with the true population size. We specified 66 days as a threshold in which SECR provides an accurate estimate in all trapping designs within the 7-times divergent density from 0.004 to 0.028 camera trap/ha. Both SECR models showed uniform tendency to overestimate abundance when sampling lasted shorter with no major differences between their outputs. Unlike the closed models, SECR performed well in the line patterns, which indicates promising potential for linear sampling of properly defined habitats of non-territorial and identifiable herbivores in dense wooded savanna conditions. The CR models provided reliable estimates in the grid and we confirmed the advantage of Mh Chao estimator over Mh jackknife when data appeared sparse. We also demonstrated the pooling of trapping occasions with an increase in the capture probabilities

  10. Application of Spatial and Closed Capture-Recapture Models on Known Population of the Western Derby Eland (Taurotragus derbianus derbianus in Senegal.

    Directory of Open Access Journals (Sweden)

    Tomáš Jůnek

    Full Text Available Camera trapping with capture-recapture analyses has provided estimates of the abundances of elusive species over the last two decades. Closed capture-recapture models (CR based on the recognition of individuals and incorporating natural heterogeneity in capture probabilities are considered robust tools; however, closure assumption is often questionable and the use of an Mh jackknife estimator may fail in estimations of real abundance when the heterogeneity is high and data is sparse. A novel, spatially explicit capture-recapture (SECR approach based on the location-specific capture histories of individuals overcomes the limitations of closed models. We applied both methods on a closed population of 16 critically endangered Western Derby elands in the fenced 1,060-ha Fathala reserve, Senegal. We analyzed the data from 30 cameras operating during a 66-day sampling period deployed in two densities in grid and line arrays. We captured and identified all 16 individuals in 962 trap-days. Abundances were estimated in the programs CAPTURE (models M0, Mh and Mh Chao and R, package secr (basic Null and Finite mixture models, and compared with the true population size. We specified 66 days as a threshold in which SECR provides an accurate estimate in all trapping designs within the 7-times divergent density from 0.004 to 0.028 camera trap/ha. Both SECR models showed uniform tendency to overestimate abundance when sampling lasted shorter with no major differences between their outputs. Unlike the closed models, SECR performed well in the line patterns, which indicates promising potential for linear sampling of properly defined habitats of non-territorial and identifiable herbivores in dense wooded savanna conditions. The CR models provided reliable estimates in the grid and we confirmed the advantage of Mh Chao estimator over Mh jackknife when data appeared sparse. We also demonstrated the pooling of trapping occasions with an increase in the capture

  11. Morphology, morphometry and ultrastructure of the Amazonian manatee (Sirenia: Trichechidae spermatozoa

    Directory of Open Access Journals (Sweden)

    Rodrigo S. Amaral

    2010-01-01

    Full Text Available This study describes the morphological, morphometric and ultrastructural characteristics of the Amazonian manatee Trichechus inunguis (Natterer, 1883 spermatozoon. The spermatozoa were obtained from a urine sample of an adult T. inunguis kept in captivity. The spermatozoa were analyzed by light and transmission electron microscopy. The head of Amazonian manatee spermatozoa had a flat oval shape and a well distinguishable midpiece. The mean dimensions of the spermatozoa were: head length, 7.49 ± 0.24 µm; head width, 3.53 ± 0.19 µm; head thickness, 1.61 ± 0.13 µm; midpiece length, 11.36 ± 0.34 µm; flagellum length, 40.91 ± 1.94 µm; total tail length, 52.16 ± 1.06 µm; total spermatozoon length, 60.08 ± 1.40 µm. The Amazonian manatee spermatozoa were similar in shape to other sirenian spermatozoa; however, presenting a different size. This study describes, for the first time, the morphometric and ultrastructural characteristics of the Amazonian manatee spermatozoa, and also demonstrates the possible use of spermatozoa retrieved from urine samples for biological studies.

  12. Governance of global climate change in the Brazilian Amazon: the case of Amazonian municipalities of Brazil

    Directory of Open Access Journals (Sweden)

    Cristina Inoue

    2012-01-01

    Full Text Available With regards to the debate about governance of climate change, it should be assumed that the Amazon region plays an important role, as this large area is highly vulnerable to its effects. In this sense, this article aims to discuss how some Amazonian municipalities of Brazil have been taking part in the complexes and multilayered processes of climate governance.

  13. Qualitative assessment of visuospatial errors in mercury-exposed Amazonian children

    DEFF Research Database (Denmark)

    Chevrier, Cécile; Sullivan, Kimberly; White, Roberta F.;

    2009-01-01

    In order to better define the effects of methylmercury (MeHg) exposure on neurodevelopment, qualitative error types observed in the responses of exposed children to the Stanford-Binet Copying Test were categorized and quantified using raw data from two studies of 395 Amazonian children aged 7-12 ...

  14. Mammalian Diversity and Matses Ethnomammalogy in Amazonian Peru. Part 1: Primates

    OpenAIRE

    Farid Pazhoohi

    2011-01-01

    Review of Mammalian Diversity and Matses Ethnomammalogy in Amazonian Peru. Part 1: Primates. Robert S. Voss and David W. Fleck. 2011. Bulletin of the American Museum of Natural History, Number 351. Pp.81, 3 figures, 25 tables. Free at AMNH Digital Library ISSN 0003‐0090.

  15. Notes on Amazonian Bittacidae (Mecoptera with the descriptions of two new species

    Directory of Open Access Journals (Sweden)

    Norman D. Penny

    1982-09-01

    Full Text Available New species of Issikiella and Nannobittacus are described and notes are presented on other Amazonian species of Mecoptera.Nova espécie de Issikiella e Nannobittacus são descritas e notas são apresentadas para outras espécies de Mecopteros da Amazônia.

  16. The Amazonian Craton and its influence on past fluvial systems (Mesozoic-Cenozoic, Amazonia)

    NARCIS (Netherlands)

    C. Hoorn; M. Roddaz; R. Dino; E. Soares; C. Uba; D. Ochoa-Lozano; R. Mapes

    2010-01-01

    The Amazonian Craton is an old geological feature of Archaean/Proterozoic age that has determined the character of fluvial systems in Amazonia throughout most of its past. This situation radically changed during the Cenozoic, when uplift of the Andes reshaped the relief and drainage patterns of nort

  17. The development of the Amazonian mega-wetland (Miocene; Brazil, Colombia, Peru, Bolivia)

    NARCIS (Netherlands)

    C. Hoorn; F.P. Wesselingh; J. Hovikoski; J. Guerrero

    2010-01-01

    The scenery of Western Amazonia once consisted of fluvial systems that originated on the Amazonian Craton and were directed towards the sub-Andean zone and the Caribbean. In the course of the Early Miocene these fluvial systems were largely replaced by lakes, swamps, tidal channels and marginal mari

  18. Recent (Late Amazonian) enhanced backweathering rates on Mars : Paracratering evidence from gully alcoves

    NARCIS (Netherlands)

    De Haas, Tjalling; Conway, Susan J.; Krautblatter, Michael

    2015-01-01

    Mars is believed to have been exposed to low planet-wide weathering and denudation since the Noachian. However, the widespread occurrence of alcoves at the rim of pristine impact craters suggests locally enhanced recent backweathering rates. Here we derive Late Amazonian backweathering rates from th

  19. Richness and composition of macrophyte assemblages in four Amazonian lakes - doi: 10.4025/actascibiolsci.v35i3.11602

    Directory of Open Access Journals (Sweden)

    Sidinei Magela Thomaz

    2013-08-01

    Full Text Available Aquatic macrophytes are an important component in the structure of lakes in Neotropical floodplains, for example, because they support a high diversity of invertebrates and vertebrates. In this paper, we tested whether or not the variability of macrophyte assemblages is lower in spatially close quadrats than among quadrats of different lakes. The study was carried in four lakes in a large Amazonian floodplain (Purus river, where floating meadows were investigated. A total of 49 taxa of macrophytes were found. Five species dominated and three species were rare. Taxa richness, composition and beta diversity differed more between than within lakes. Because high beta diversity was found among the lakes, they should be considered individually important for maintaining the gamma diversity of macrophytes within the Purus River floodplain, and this should be considered in plans of lake management.  

  20. Road Development and the Geography of Hunting by an Amazonian Indigenous Group: Consequences for Wildlife Conservation

    OpenAIRE

    Espinosa, Santiago; Branch, Lyn C.; Cueva, Rubén

    2014-01-01

    Protected areas are essential for conservation of wildlife populations. However, in the tropics there are two important factors that may interact to threaten this objective: 1) road development associated with large-scale resource extraction near or within protected areas; and 2) historical occupancy by traditional or indigenous groups that depend on wildlife for their survival. To manage wildlife populations in the tropics, it is critical to understand the effects of roads on the spatial ext...

  1. Estimating Amazonian methane emissions through 4D-Var inverse modelling with satellite observations from GOSAT and IASI

    Science.gov (United States)

    Wilson, C. J.; Chipperfield, M.; Gloor, M.; McNorton, J.; Miller, J. B.; Gatti, L. V.; Siddans, R.; Bloom, A. A.; Basso, L. S.; Boesch, H.; Parker, R.; Monks, S. A.

    2015-12-01

    Methane (CH4) is emitted from a range of anthropogenic and natural sources, and since the industrial revolution its mean atmospheric concentration has climbed dramatically. CH4 produces a relatively high radiative forcing effect upon the Earth's climate, and its atmospheric lifetime of approximately 10 years makes it an appealing target for the mitigation of climate change. However, the spatial and temporal variation of CH4 emissions are not well understood, though in recent years a number of top-down and bottom-up studies have attempted to construct improved emission budgets. However, some top-down studies suffer from poor observational coverage near the Amazon basin, particularly in the planetary boundary layer. Since emissions from this region, coming mainly from wetland and burning sources, are thought to be relatively high, additional observations in this region would greatly help to constrain the geographical distribution of the global CH4 emission budget. To this end, regular flask measurements of CH4 and other trace gases have been taken during flights over four Amazonian sites since 2010, as part of the AMAZONICA project. The GOSAT has been used to retrieve global column-average CH4 concentrations since mid-2009, whilst IASI, on-board Metop-A, has also been measuring atmospheric CH4 concentrations since its launch in 2006. We present an assessment of Amazonian methane emissions for 2010 and 2011 using the TOMCAT Chemical Transport Model and the new variational inverse model, INVICAT. These models are used to attribute methane variations at each Amazon site to a source type and region, to assess the ability of our current CH4 flux estimates to reproduce these observations and to produce improved posterior emission estimates through assimilation of atmospheric observations. This study represents the first use of the INVICAT scheme to constrain emissions of any atmospheric trace gas. Whilst there is generally good agreement between the model and the

  2. Spatial Genetic Structure of Two HIV-I-resistant Polymorphisms (CCR2-64Ⅰand SDF1-3'A) Alleles in Population of Shandong Province, China

    Institute of Scientific and Technical