WorldWideScience

Sample records for lowland congo tropical

  1. Population dynamics of Rodents and Insectivores in lowland tropical ...

    African Journals Online (AJOL)

    The community structure of rodents and insectivores in the lowland tropical rainforest of Okomu National Park, Edo State, Nigeria was assessed using a combination of live-trapping and sighting techniques during the dry and wet seasons. Seventeen species (14 species of rodent, 3 species of insectivores) were captured, ...

  2. Impacts of warming on tropical lowland rainforests.

    Science.gov (United States)

    Corlett, Richard T

    2011-11-01

    Before the end of this century, tropical rainforests will be subject to climatic conditions that have not existed anywhere on Earth for millions of years. These forests are the most species-rich ecosystems in the world and play a crucial role in regulating carbon and water feedbacks in the global climate system; therefore, it is important that the probable impacts of anthropogenic climate change are understood. However, the recent literature shows a striking range of views on the vulnerability of tropical rainforests, from least to most concern among major ecosystems. This review, which focuses on the impact of rising temperatures, examines the evidence for and against high vulnerability, identifies key research needs for resolving current differences and suggests ways of mitigating or adapting to potential impacts. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Aboveground vs. Belowground Carbon Stocks in African Tropical Lowland Rainforest: Drivers and Implications.

    Directory of Open Access Journals (Sweden)

    Sebastian Doetterl

    Full Text Available African tropical rainforests are one of the most important hotspots to look for changes in the upcoming decades when it comes to C storage and release. The focus of studying C dynamics in these systems lies traditionally on living aboveground biomass. Belowground soil organic carbon stocks have received little attention and estimates of the size, controls and distribution of soil organic carbon stocks are highly uncertain. In our study on lowland rainforest in the central Congo basin, we combine both an assessment of the aboveground C stock with an assessment of the belowground C stock and analyze the latter in terms of functional pools and controlling factors.Our study shows that despite similar vegetation, soil and climatic conditions, soil organic carbon stocks in an area with greater tree height (= larger aboveground carbon stock were only half compared to an area with lower tree height (= smaller aboveground carbon stock. This suggests that substantial variability in the aboveground vs. belowground C allocation strategy and/or C turnover in two similar tropical forest systems can lead to significant differences in total soil organic C content and C fractions with important consequences for the assessment of the total C stock of the system.We suggest nutrient limitation, especially potassium, as the driver for aboveground versus belowground C allocation. However, other drivers such as C turnover, tree functional traits or demographic considerations cannot be excluded. We argue that large and unaccounted variability in C stocks is to be expected in African tropical rain-forests. Currently, these differences in aboveground and belowground C stocks are not adequately verified and implemented mechanistically into Earth System Models. This will, hence, introduce additional uncertainty to models and predictions of the response of C storage of the Congo basin forest to climate change and its contribution to the terrestrial C budget.

  4. Aboveground vs. Belowground Carbon Stocks in African Tropical Lowland Rainforest: Drivers and Implications.

    Science.gov (United States)

    Doetterl, Sebastian; Kearsley, Elizabeth; Bauters, Marijn; Hufkens, Koen; Lisingo, Janvier; Baert, Geert; Verbeeck, Hans; Boeckx, Pascal

    2015-01-01

    African tropical rainforests are one of the most important hotspots to look for changes in the upcoming decades when it comes to C storage and release. The focus of studying C dynamics in these systems lies traditionally on living aboveground biomass. Belowground soil organic carbon stocks have received little attention and estimates of the size, controls and distribution of soil organic carbon stocks are highly uncertain. In our study on lowland rainforest in the central Congo basin, we combine both an assessment of the aboveground C stock with an assessment of the belowground C stock and analyze the latter in terms of functional pools and controlling factors. Our study shows that despite similar vegetation, soil and climatic conditions, soil organic carbon stocks in an area with greater tree height (= larger aboveground carbon stock) were only half compared to an area with lower tree height (= smaller aboveground carbon stock). This suggests that substantial variability in the aboveground vs. belowground C allocation strategy and/or C turnover in two similar tropical forest systems can lead to significant differences in total soil organic C content and C fractions with important consequences for the assessment of the total C stock of the system. We suggest nutrient limitation, especially potassium, as the driver for aboveground versus belowground C allocation. However, other drivers such as C turnover, tree functional traits or demographic considerations cannot be excluded. We argue that large and unaccounted variability in C stocks is to be expected in African tropical rain-forests. Currently, these differences in aboveground and belowground C stocks are not adequately verified and implemented mechanistically into Earth System Models. This will, hence, introduce additional uncertainty to models and predictions of the response of C storage of the Congo basin forest to climate change and its contribution to the terrestrial C budget.

  5. Population structure and group composition of western lowland gorillas in north-western Republic of Congo.

    Science.gov (United States)

    Magliocca, F; Querouil, S; Gautier-Hion, A

    1999-01-01

    Population studies are an essential part of conservation actions. Under exceptional observation conditions we studied a western lowland gorilla population visiting the Maya salt-clearing (north of the Parc national d'Odzala, P.N.O., Congo) over an 8 month period; 36 groups and 18 solitary individuals (a total of 420 individuals) have been identified visiting the clearing, which suggests a high gorilla density in the region. Ninety-six percent of the gorillas entered the clearing in groups. One-male groups had a mean size of 11.2. Ninety percent of solitary individuals were silver-back males. Compared with other populations of both lowland gorillas and mountain gorillas, the Maya population had the highest immature rate and the highest number of infants per female. Ecological correlates that could explain the attractiveness of the Maya clearing are discussed. The present status and the renewal rate of the Maya population indicate the need for further studies and confirm the importance of developing eco-tourism in this region as part of the sustainable park management activities developed by the ECOFAC programme (European Union). The results also provide arguments to support the proposal for extending the P.N.O. to include this region, which is rich in salt-clearings and attracts many other key-species of mammal such as forest elephants.

  6. Rainfall interception from a lowland tropical rainforest in Brunei

    Science.gov (United States)

    Dykes, A. P.

    1997-12-01

    Results from a programme of throughfall measurements in a lowland tropical rainforest in Brunei, northwest Borneo, indicate that interception losses amount to 18% of the gross incident rainfall. The high annual rainfall experienced by the study area results in annual interception losses of around 800 mm, which may result in total annual evapotranspiration losses significantly higher than in other rainforest locations. An improved version of Gash's analytical interception model is tested on the available data using assumed values for the "forest" parameters, and is found to predict interception losses extremely well. The model predictions are based on an estimated evaporation rate during rainfall of 0.71 mm h -1. This is significantly higher than has been reported in other tropical studies. It is concluded that these results are distinctive when compared with previous results from rainforests, and that further, detailed work is required to establish whether the enhanced evaporation rate is due to advective effects associated with the maritime setting of the study area.

  7. Lowland extirpation of anuran populations on a tropical mountain

    Science.gov (United States)

    Aide, T. Mitchell

    2017-01-01

    Background Climate change and infectious diseases threaten animal and plant species, even in natural and protected areas. To cope with these changes, species may acclimate, adapt, move or decline. Here, we test for shifts in anuran distributions in the Luquillo Mountains (LM), a tropical montane forest in Puerto Rico by comparing species distributions from historical (1931–1989)and current data (2015/2016). Methods Historical data, which included different methodologies, were gathered through the Global Biodiversity Information Facility (GBIF) and published literature, and the current data were collected using acoustic recorders along three elevational transects. Results In the recordings, we detected the 12 native frog species known to occur in LM. Over a span of ∼25 years, two species have become extinct and four species suffered extirpation in lowland areas. As a consequence, low elevation areas in the LM (indicate that (1) climate change has increased temperatures in Puerto Rico, and (2) Batrachochytrium dendrobatidis (Bd) was found in 10 native species and early detection of Bd coincides with anurans declines in the LM. Our study confirms the general impressions of amphibian population extirpations at low elevations, and corroborates the levels of threat assigned by IUCN. PMID:29158987

  8. Lowland extirpation of anuran populations on a tropical mountain

    Directory of Open Access Journals (Sweden)

    Marconi Campos-Cerqueira

    2017-11-01

    Full Text Available Background Climate change and infectious diseases threaten animal and plant species, even in natural and protected areas. To cope with these changes, species may acclimate, adapt, move or decline. Here, we test for shifts in anuran distributions in the Luquillo Mountains (LM, a tropical montane forest in Puerto Rico by comparing species distributions from historical (1931–1989and current data (2015/2016. Methods Historical data, which included different methodologies, were gathered through the Global Biodiversity Information Facility (GBIF and published literature, and the current data were collected using acoustic recorders along three elevational transects. Results In the recordings, we detected the 12 native frog species known to occur in LM. Over a span of ∼25 years, two species have become extinct and four species suffered extirpation in lowland areas. As a consequence, low elevation areas in the LM (<300 m have lost at least six anuran species. Discussion We hypothesize that these extirpations are due to the effects of climate change and infectious diseases, which are restricting many species to higher elevations and a much smaller area. Land use change is not responsible for these changes because LM has been a protected reserve for the past 80 years. However, previous studies indicate that (1 climate change has increased temperatures in Puerto Rico, and (2 Batrachochytrium dendrobatidis (Bd was found in 10 native species and early detection of Bd coincides with anurans declines in the LM. Our study confirms the general impressions of amphibian population extirpations at low elevations, and corroborates the levels of threat assigned by IUCN.

  9. Stability and instability on Maya Lowlands tropical hillslope soils

    Science.gov (United States)

    Beach, Timothy; Luzzadder-Beach, Sheryl; Cook, Duncan; Krause, Samantha; Doyle, Colin; Eshleman, Sara; Wells, Greta; Dunning, Nicholas; Brennan, Michael L.; Brokaw, Nicholas; Cortes-Rincon, Marisol; Hammond, Gail; Terry, Richard; Trein, Debora; Ward, Sheila

    2018-03-01

    Substantial lake core and other evidence shows accelerated soil erosion occurred in the Maya Lowlands of Central America over ancient Maya history from 3000 to 1000 years ago. But we have little evidence of the wider network of the sources and sinks of that eroded sediment cascade. This study begins to solve the mystery of missing soil with new research and a synthesis of existing studies of tropical forest soils along slopes in NW Belize. The research aim is to understand soil formation, long-term human impacts on slopes, and slope stability over time, and explore ecological implications. We studied soils on seven slopes in tropical forest areas that have experienced intensive ancient human impacts and those with little ancient impacts. All of our soil catenas, except for one deforested from old growth two years before, contain evidence for about 1000 years of stable, tropical forest cover since Maya abandonment. We characterized the physical, chemical, and taxonomic characteristics of soils at crest-shoulder, backslopes, footslopes, and depression locations, analyzing typical soil parameters, chemical elements, and carbon isotopes (δ13C) in dated and undated sequences. Four footslopes or depressions in areas of high ancient occupation preserved evidence of buried, clay-textured soils covered by coarser sediment dating from the Maya Classic period. Three footslopes from areas with scant evidence of ancient occupation had little discernable deposition. These findings add to a growing corpus of soil toposequences with similar facies changes in footslopes and depressions that date to the Maya period. Using major elemental concentrations across a range of catenas, we derived a measure (Ca + Mg) / (Al + Fe + Mn) of the relative contributions of autochthonous and allochthonous materials and the relative age of soil catenas. We found very low ratios in clearly older, buried soils in footslopes and depressions and on slopes that had not undergone ancient Maya erosion. We

  10. Simple greenhouse climate model as a design tool for greenhouses in tropical lowland

    NARCIS (Netherlands)

    Impron, I.; Hemming-Hoffmann, S.; Bot, G.P.A.

    2007-01-01

    Six prototypes plastic greenhouses were built in the tropical lowlands of Indonesia. The geometrical dimensions were designed using computational fluid dynamics (CFD) by taking local climate parameters as static reference boundary conditions. It is necessary to evaluate the climate dynamics inside

  11. No evidence that boron influences tree species distributions in lowland tropical forests of Panama.

    Science.gov (United States)

    Turner, Benjamin L; Zalamea, Paul-Camilo; Condit, Richard; Winter, Klaus; Wright, S Joseph; Dalling, James W

    2017-04-01

    It was recently proposed that boron might be the most important nutrient structuring tree species distributions in tropical forests. Here we combine observational and experimental studies to test this hypothesis for lowland tropical forests of Panama. Plant-available boron is uniformly low in tropical forest soils of Panama and is not significantly associated with any of the > 500 species in a regional network of forest dynamics plots. Experimental manipulation of boron supply to seedlings of three tropical tree species revealed no evidence of boron deficiency or toxicity at concentrations likely to occur in tropical forest soils. Foliar boron did not correlate with soil boron along a local scale gradient of boron availability. Fifteen years of boron addition to a tropical forest increased plant-available boron by 70% but did not significantly change tree productivity or boron concentrations in live leaves, wood or leaf litter. The annual input of boron in rainfall accounts for a considerable proportion of the boron in annual litterfall and is similar to the pool of plant-available boron in the soil, and is therefore sufficient to preclude boron deficiency. We conclude that boron does not influence tree species distributions in Panama and presumably elsewhere in the lowland tropics. No claim to original US government works New Phytologist © 2016 New Phytologist Trust.

  12. Microorganisms in Soils of Bovine Production Systems in Tropical Lowlands and Tropical Highlands in the Department of Antioquia, Colombia

    OpenAIRE

    Molina-Guzmán, Licet Paola; Henao-Jaramillo, Paula Andrea; Gutiérrez-Builes, Lina Andrea; Ríos-Osorio, Leonardo Alberto

    2018-01-01

    Studies on the physical and chemical effects of extensive grazing on soils have been performed in Colombia, but the effects of dairy cattle rearing on the biological properties of soils are not well known. The objective of this study was to evaluate microorganisms in 48 soils from livestock farms in the highland and lowland tropics in the Northern and Magdalena Medio subregions of the Department of Antioquia (Colombia). Principal component analysis demonstrated differences in the edaphic comp...

  13. Microorganisms in Soils of Bovine Production Systems in Tropical Lowlands and Tropical Highlands in the Department of Antioquia, Colombia

    Directory of Open Access Journals (Sweden)

    Licet Paola Molina-Guzmán

    2018-01-01

    Full Text Available Studies on the physical and chemical effects of extensive grazing on soils have been performed in Colombia, but the effects of dairy cattle rearing on the biological properties of soils are not well known. The objective of this study was to evaluate microorganisms in 48 soils from livestock farms in the highland and lowland tropics in the Northern and Magdalena Medio subregions of the Department of Antioquia (Colombia. Principal component analysis demonstrated differences in the edaphic compositions of the soils, with increased percentages of root colonization by arbuscular mycorrhizal fungi and the density of microorganisms in farms that have soils with moderate phosphorus and nitrogen contents, low potassium content, and a moderately acidic pH. Agglomerative cluster analysis showed two groups for the highland tropic soils and six groups for the lowland tropic soils based on their population densities and interactions with the studied parameters. These results represent a first attempt to describe the density of microorganisms and the effect of soil physicochemical parameters on colonization by arbuscular mycorrhizal fungi in areas with determinant agroecological conditions, microbial functional diversity, and the presence of mycorrhizal fungi in livestock farm soils in Colombia.

  14. Vegetation and floristics of a lowland tropical rainforest in northeast Australia

    Science.gov (United States)

    Apgaua, Deborah M. G.; Campbell, Mason J; Cox, Casey J; Crayn, Darren M; Ishida, Françoise Y; Laidlaw, Melinda J; Liddell, Michael J; Seager, Michael; Laurance, Susan G. W.

    2016-01-01

    Abstract Background Full floristic data, tree demography, and biomass estimates incorporating non-tree lifeforms are seldom collected and reported for forest plots in the tropics. Established research stations serve as important repositories of such biodiversity and ecological data. With a canopy crane setup within a tropical lowland rainforest estate, the 42-ha Daintree Rainforest Observatory (DRO) in Cape Tribulation, northern Australia is a research facility of international significance. We obtained an estimate of the vascular plant species richness for the site, by surveying all vascular plant species from various mature-phase, remnant and open vegetation patches within the site. We also integrate and report the demography and basal areas of trees ≥ 10 cm diameter at breast height (dbh) in a new 1-ha core plot, an extension to the pre-existing forest 1-ha plot under the canopy crane. In addition, we report for the canopy crane plot new demography and basal areas for smaller-size shrubs and treelets subsampled from nine 20 m2 quadrats, and liana basal area and abundance from the whole plot. The DRO site has an estimated total vascular plant species richness of 441 species, of which 172 species (39%) are endemic to Australia, and 4 species are endemics to the Daintree region. The 2 x 1-ha plots contains a total of 262 vascular plant species of which 116 (1531 individuals) are tree species ≥ 10 cm dbh. We estimate a stem basal area of 34.9 m2 ha-1, of which small stems (tree saplings and shrubs rainforests globally, our meta-analysis shows that DRO forests has a comparatively high stem density and moderate species diversity, due to the influence of cyclones. These data will provide an important foundation for ecological and conservation studies in lowland tropical forest. New information We present a floristic checklist, a lifeform breakdown, and demography data from two 1-ha rainforest plots from a lowland tropical rainforest study site. We also present a

  15. Vegetation and floristics of a lowland tropical rainforest in northeast Australia.

    Science.gov (United States)

    Tng, David Y P; Apgaua, Deborah M G; Campbell, Mason J; Cox, Casey J; Crayn, Darren M; Ishida, Françoise Y; Laidlaw, Melinda J; Liddell, Michael J; Seager, Michael; Laurance, Susan G W

    2016-01-01

    Full floristic data, tree demography, and biomass estimates incorporating non-tree lifeforms are seldom collected and reported for forest plots in the tropics. Established research stations serve as important repositories of such biodiversity and ecological data. With a canopy crane setup within a tropical lowland rainforest estate, the 42-ha Daintree Rainforest Observatory (DRO) in Cape Tribulation, northern Australia is a research facility of international significance. We obtained an estimate of the vascular plant species richness for the site, by surveying all vascular plant species from various mature-phase, remnant and open vegetation patches within the site. We also integrate and report the demography and basal areas of trees ≥ 10 cm diameter at breast height (dbh) in a new 1-ha core plot, an extension to the pre-existing forest 1-ha plot under the canopy crane. In addition, we report for the canopy crane plot new demography and basal areas for smaller-size shrubs and treelets subsampled from nine 20 m(2) quadrats, and liana basal area and abundance from the whole plot. The DRO site has an estimated total vascular plant species richness of 441 species, of which 172 species (39%) are endemic to Australia, and 4 species are endemics to the Daintree region. The 2 x 1-ha plots contains a total of 262 vascular plant species of which 116 (1531 individuals) are tree species ≥ 10 cm dbh. We estimate a stem basal area of 34.9 m(2) ha(-1), of which small stems (tree saplings and shrubs analysis shows that DRO forests has a comparatively high stem density and moderate species diversity, due to the influence of cyclones. These data will provide an important foundation for ecological and conservation studies in lowland tropical forest. We present a floristic checklist, a lifeform breakdown, and demography data from two 1-ha rainforest plots from a lowland tropical rainforest study site. We also present a meta-analysis of stem densities and species diversity from

  16. Wild Pigs (Sus scrofa) Mediate Large-Scale Edge Effects in a Lowland Tropical Rainforest in Peninsular Malaysia

    OpenAIRE

    Fujinuma, Junichi; Harrison, Rhett D.

    2012-01-01

    Edge-effects greatly extend the area of tropical forests degraded through human activities. At Pasoh, Peninsular Malaysia, it has been suggested that soil disturbance by highly abundant wild pigs (Sus scrofa), which feed in adjacent Oil Palm plantations, may have mediated the invasion of Clidemia hirta (Melastomataceae) into the diverse tropical lowland rain forest. To investigate this hypothesis, we established three 1 km transects from the forest/Oil Palm plantation boundary into the forest...

  17. A Greenhouse for Tropical Lowlands (Malaysia), Training manual : Guidelines for the Planning and Organisation of Training Activities

    NARCIS (Netherlands)

    Elings, A.; Stijger, I.; Blomne Sopov, M.; Campen, J.B.; Runia, L.

    2012-01-01

    This Training Manual on tropical lowland greenhouse horticulture has been prepared as a manual for training of trainers staff of the Department of Agriculture of Malaysia, agricultural extension workers of the government, trainers of educational institutes engaged in greenhouse training and for

  18. Functional Traits and Water Transport Strategies in Lowland Tropical Rainforest Trees

    Science.gov (United States)

    Apgaua, Deborah M. G.; Ishida, Françoise Y.; Tng, David Y. P.; Laidlaw, Melinda J.; Santos, Rubens M.; Rumman, Rizwana; Eamus, Derek; Holtum, Joseph A. M.; Laurance, Susan G. W.

    2015-01-01

    Understanding how tropical rainforest trees may respond to the precipitation extremes predicted in future climate change scenarios is paramount for their conservation and management. Tree species clearly differ in drought susceptibility, suggesting that variable water transport strategies exist. Using a multi-disciplinary approach, we examined the hydraulic variability in trees in a lowland tropical rainforest in north-eastern Australia. We studied eight tree species representing broad plant functional groups (one palm and seven eudicot mature-phase, and early-successional trees). We characterised the species’ hydraulic system through maximum rates of volumetric sap flow and velocities using the heat ratio method, and measured rates of tree growth and several stem, vessel, and leaf traits. Sap flow measures exhibited limited variability across species, although early-successional species and palms had high mean sap velocities relative to most mature-phase species. Stem, vessel, and leaf traits were poor predictors of sap flow measures. However, these traits exhibited different associations in multivariate analysis, revealing gradients in some traits across species and alternative hydraulic strategies in others. Trait differences across and within tree functional groups reflect variation in water transport and drought resistance strategies. These varying strategies will help in our understanding of changing species distributions under predicted drought scenarios. PMID:26087009

  19. Performance of 'Valencia' sweet orange grafted in different rootstocks, Colombia Tropical Lowland. 2001-2013

    Directory of Open Access Journals (Sweden)

    Hans Nicolas Chaparro-Zambrano

    2015-04-01

    Full Text Available 'Valencia' sweet orange is widely cultivated in Colombian tropical lowlands, with low yields and a lack of technology. As a result, nine rootstocks commonly used in tropical zones: 'C-35', 'Carrizo', 'Swingle' citrumelo or CPB 4475, 'Cleopatra', 'Sunki × English', 'Volkamer', 'Webberi' and 'Yuma' were evaluated. The plants were established in 2001 and were evaluated for vegetative growth, fruit yield and quality for 10 years (2004-2013. The obtained results indicated that 'Sunki × English' and 'Volkamer' were the best rootstocks for fruit yield and the worst was 'Yuma'. Furthermore, all of the rootstocks, except 'Yuma', stabilized their height in the last year. In terms of volume, 'Amblycarpa' and 'Cleopatra' were the bigger plants and 'Yuma' was the smallest. In addition, for yield efficiency, 'Yuma' had the best rootstocks, followed by 'Sunki × English'. All of the rootstocks showed a similar fruit quality, except for 'Sunki × English', which obtained the highest total soluble solids/total titratable acids ratio.

  20. Functional Traits and Water Transport Strategies in Lowland Tropical Rainforest Trees.

    Directory of Open Access Journals (Sweden)

    Deborah M G Apgaua

    Full Text Available Understanding how tropical rainforest trees may respond to the precipitation extremes predicted in future climate change scenarios is paramount for their conservation and management. Tree species clearly differ in drought susceptibility, suggesting that variable water transport strategies exist. Using a multi-disciplinary approach, we examined the hydraulic variability in trees in a lowland tropical rainforest in north-eastern Australia. We studied eight tree species representing broad plant functional groups (one palm and seven eudicot mature-phase, and early-successional trees. We characterised the species' hydraulic system through maximum rates of volumetric sap flow and velocities using the heat ratio method, and measured rates of tree growth and several stem, vessel, and leaf traits. Sap flow measures exhibited limited variability across species, although early-successional species and palms had high mean sap velocities relative to most mature-phase species. Stem, vessel, and leaf traits were poor predictors of sap flow measures. However, these traits exhibited different associations in multivariate analysis, revealing gradients in some traits across species and alternative hydraulic strategies in others. Trait differences across and within tree functional groups reflect variation in water transport and drought resistance strategies. These varying strategies will help in our understanding of changing species distributions under predicted drought scenarios.

  1. Functional Traits and Water Transport Strategies in Lowland Tropical Rainforest Trees.

    Science.gov (United States)

    Apgaua, Deborah M G; Ishida, Françoise Y; Tng, David Y P; Laidlaw, Melinda J; Santos, Rubens M; Rumman, Rizwana; Eamus, Derek; Holtum, Joseph A M; Laurance, Susan G W

    2015-01-01

    Understanding how tropical rainforest trees may respond to the precipitation extremes predicted in future climate change scenarios is paramount for their conservation and management. Tree species clearly differ in drought susceptibility, suggesting that variable water transport strategies exist. Using a multi-disciplinary approach, we examined the hydraulic variability in trees in a lowland tropical rainforest in north-eastern Australia. We studied eight tree species representing broad plant functional groups (one palm and seven eudicot mature-phase, and early-successional trees). We characterised the species' hydraulic system through maximum rates of volumetric sap flow and velocities using the heat ratio method, and measured rates of tree growth and several stem, vessel, and leaf traits. Sap flow measures exhibited limited variability across species, although early-successional species and palms had high mean sap velocities relative to most mature-phase species. Stem, vessel, and leaf traits were poor predictors of sap flow measures. However, these traits exhibited different associations in multivariate analysis, revealing gradients in some traits across species and alternative hydraulic strategies in others. Trait differences across and within tree functional groups reflect variation in water transport and drought resistance strategies. These varying strategies will help in our understanding of changing species distributions under predicted drought scenarios.

  2. Estimates of Crossbreeding Parameters for Defining Optimal Crossbreeding Systems for the Coastal Lowland Tropics

    International Nuclear Information System (INIS)

    Kahi, A.K.; Thorpe, W.

    1999-01-01

    An individual animal model was fitted to data from crossbred herd in the lowland coastal tropics of Kenya to estimate breed cross means for a total of 25 genotypes having different proportions of Ayrshire (A), Brown swiss (B), Friesian (F) and Sahiwal (S) genes. These means were then regressed on gene proportion of breeds and on the coefficients of heterosis and recombination loss. Per lactation, the S contributed 1802 kg and 18.4 kg less milk and milk per unit of metabolic weight (MW), respectively, than the F. The performance of A and B were intermediate. The contribution of the F breed for most traits was superior to that of the other Bos taurus breeds. the heterosis effect between B and S was large for lactation milk yield (MY) (296 kg) and calving interval (CL) (-36 days). The heterosis between A and B for most traits was small, which is consistent with other studies in the literature. The estimates of recombination loss were negative in crosses A * B and B * S for MY,daily milk yield (DMY) and MY expressed per unit MW. Modelling of alternative crossbreeding strategy should be considered in relation to the ecological and socio-economic characteristics of the target production systems, which vary markedly. Therefore, the generalisation that the first cross (F 1 ) is best suited for dairying in the tropics could be misleading, and there is the need to evaluate the potential of synthetic breeds

  3. Rainforests north of the Tropic of Cancer: Physiognomy, floristics and diversity in ‘lowland rainforests’ of Meghalaya, India

    Directory of Open Access Journals (Sweden)

    Uma Shankar

    2017-02-01

    Full Text Available The lowland rainforests of Meghalaya, India represent the westernmost limit of the rainforests north of the Tropic of Cancer. These forests, on the Shillong plateau, are akin to Whitmore's ‘tropical lowland evergreen rainforest’ formation and exhibit striking similarities and conspicuous differences with the equatorial rainforests in Asia-Pacific as well as tropical seasonal rainforests in southwestern China near the Tropic of Cancer. We found these common attributes of the rainforests in Meghalaya: familial composition with predominance of Euphorbiaceae, Lauraceae, Meliaceae, Moraceae, Myrsiticaceae, Myrtaceae and Rubiaceae; deciduousness in evergreen physiognomy; dominance of mega- and mesophanerophytic life-forms; abundance of species with low frequency of occurrence (rare and aggregated species; low proportional abundance of the abundant species; and truncated lognormal abundance distribution. The levels of stand density and stand basal area were comparable with seasonal rainforests in southwestern China, but were lower than equatorial rainforests. Tropical Asian species predominated flora, commanding 95% of the abundance. The differences include overall low stature (height of the forest, inconspicuous stratification in canopy, fewer species and individuals of liana, thicker understory, higher proportion of rare species, absence of locally endemic species and relatively greater dominance of Fagaceae and Theaceae. The richness of species per hectare (S was considerably lower at higher latitudes in Meghalaya than in equatorial rainforests, but was comparable with seasonal rainforests. Shannon's diversity index (H′ = 4.40 nats for ≥10 cm gbh and 4.25 nats for ≥30 cm gbh was lower on higher latitudes in Meghalaya in comparison to species-rich equatorial rainforests, but it was the highest among all lowland rainforests near the Tropic of Cancer.

  4. Development of Tropical Lowland Peat Forest Phasic Community Zonations in the Kota Samarahan-Asajaya area, West Sarawak, Malaysia

    Directory of Open Access Journals (Sweden)

    Mohamad Tarmizi Mohamad

    2016-01-01

    Full Text Available Logging observations of auger profiles (Tarmizi, 2014 indicate a vertical, downwards, general decrease of peat humification levels with depth in a tropical lowland peat forest in the Kota Samarahan-Asajaya area in the region of West Sarawak (Malaysia. Based on pollen analyses and field observations, the studied peat profiles can be interpreted as part of a progradation deltaic succession. Continued regression of sea levels, gave rise to the development of peat in a transitional mangrove to floodplain/floodbasin environment, followed by a shallow, topogenic peat depositional environment with riparian influence at approximately 2420 ± 30 years B.P. (until present time. The inferred peat vegetational succession reached Phasic Community I at approximately 2380 ± 30 years B.P. and followed by Phasic Community II at approximately 1780 ± 30 years B.P., towards the upper part of the present, ombrogenic, peat profile. Observations of the presence of large, hollow, Shorea type trees, supports that successive vegetational zonation of the tropical lowland peat dome may have reached Phasic Community II. Some pollen types were found that are also known to occur in the inferred vegetational zonation of Phasic Community III and IV or higher. Pollen analyses indicate that estuarine and deltaic, brackish to saline water influence may have gradually ceased at approximately 0.5 m below the lithological boundary between peat and underlying soil (floodplain deposit in the tropical lowland peat basin.

  5. Biogenic volatile organic compound emissions from a lowland tropical wet forest in Costa Rica

    Energy Technology Data Exchange (ETDEWEB)

    Geron, C. [United States Environmental Protection Agency, Research Triangle Park, NC (United States). National Risk Management Research Lab.; Guenther, A.; Greenberg, J. [National Center for Atmospheric Research, Boulder, CO (United States); Loescher, H.W. [University of Florida, Gainesville, FL (United States). School of Forest Resources and Conservation; Clark, D. [University of Missouri-St. Louis, MS (United States). Dept. of Biology; Baker, B. [South Dakota School of Mines and Technology, Rapid City, SD (United States)

    2002-08-01

    Twenty common plant species were screened for emissions of biogenic volatile organic compounds (BVOCs) at a lowland tropical wet forest site in Costa Rica. Ten of the species examined emitted substantial quantities of isoprene. These species accounted for 35-50% of the total basal area of old-growth forest on the major edaphic site types, indicating that a high proportion of the canopy leaf area is a source of isoprene. A limited number of canopy-level BVOC flux measurements were also collected by relaxed eddy accumulation (REA). These measurements verify that the forest canopy in this region is indeed a significant source of isoprene. In addition, REA fluxes of methanol and especially acetone were also significant, exceeding model estimates and warranting future investigation at this site. Leaf monoterpene emissions were non-detectable or very low from the species surveyed, and ambient concentrations and REA fluxes likewise were very low. Although the isoprene emission rates reported here are largely consistent with phylogenetic relations found in other studies (at the family, genus, and species levels), two species in the family Mimosaceae, a group previously found to consist largely of non-isoprene emitters, emitted significant quantities of isoprene. One of these, Pentaclethra macroloba (Willd.) Kuntze, is by far the most abundant canopy tree species in the forests of this area, composing 30-40% of the total basal area. The other, Zygia longifolia (Humb. and Bonpl.) Britton and Rose is a common riparian species. Our results suggest that the source strength of BVOCs is important not only to tropical atmospheric chemistry, but also may be important in determining net ecosystem carbon exchange.(author)

  6. Ecosystem consequences of tree monodominance for nitrogen cycling in lowland tropical forest.

    Science.gov (United States)

    Brookshire, E N Jack; Thomas, Steven A

    2013-01-01

    Understanding how plant functional traits shape nutrient limitation and cycling on land is a major challenge in ecology. This is especially true for lowland forest ecosystems of the tropics which can be taxonomically and functionally diverse and rich in bioavailable nitrogen (N). In many tropical regions, however, diverse forests occur side-by-side with monodominant forest (one species >60% of canopy); the long-term biogeochemical consequences of tree monodominance are unclear. Particularly uncertain is whether the monodominant plant-soil system modifies nutrient balance at the ecosystem level. Here, we use chemical and stable isotope techniques to examine N cycling in old-growth Mora excelsa and diverse watershed rainforests on the island of Trinidad. Across 26 small watershed forests and 4 years, we show that Mora monodominance reduces bioavailable nitrate in the plant-soil system to exceedingly low levels which, in turn, results in small hydrologic and gaseous N losses at the watershed-level relative to adjacent N-rich diverse forests. Bioavailable N in soils and streams remained low and remarkably stable through time in Mora forests; N levels in diverse forests, on the other hand, showed high sensitivity to seasonal and inter-annual rainfall variation. Total mineral N losses from diverse forests exceeded inputs from atmospheric deposition, consistent with N saturation, while losses from Mora forests did not, suggesting N limitation. Our measures suggest that this difference cannot be explained by environmental factors but instead by low internal production and efficient retention of bioavailable N in the Mora plant-soil system. These results demonstrate ecosystem-level consequences of a tree species on the N cycle opposite to cases where trees enhance ecosystem N supply via N2 fixation and suggest that, over time, Mora monodominance may generate progressive N draw-down in the plant-soil system.

  7. Ecosystem consequences of tree monodominance for nitrogen cycling in lowland tropical forest.

    Directory of Open Access Journals (Sweden)

    E N Jack Brookshire

    Full Text Available Understanding how plant functional traits shape nutrient limitation and cycling on land is a major challenge in ecology. This is especially true for lowland forest ecosystems of the tropics which can be taxonomically and functionally diverse and rich in bioavailable nitrogen (N. In many tropical regions, however, diverse forests occur side-by-side with monodominant forest (one species >60% of canopy; the long-term biogeochemical consequences of tree monodominance are unclear. Particularly uncertain is whether the monodominant plant-soil system modifies nutrient balance at the ecosystem level. Here, we use chemical and stable isotope techniques to examine N cycling in old-growth Mora excelsa and diverse watershed rainforests on the island of Trinidad. Across 26 small watershed forests and 4 years, we show that Mora monodominance reduces bioavailable nitrate in the plant-soil system to exceedingly low levels which, in turn, results in small hydrologic and gaseous N losses at the watershed-level relative to adjacent N-rich diverse forests. Bioavailable N in soils and streams remained low and remarkably stable through time in Mora forests; N levels in diverse forests, on the other hand, showed high sensitivity to seasonal and inter-annual rainfall variation. Total mineral N losses from diverse forests exceeded inputs from atmospheric deposition, consistent with N saturation, while losses from Mora forests did not, suggesting N limitation. Our measures suggest that this difference cannot be explained by environmental factors but instead by low internal production and efficient retention of bioavailable N in the Mora plant-soil system. These results demonstrate ecosystem-level consequences of a tree species on the N cycle opposite to cases where trees enhance ecosystem N supply via N2 fixation and suggest that, over time, Mora monodominance may generate progressive N draw-down in the plant-soil system.

  8. Carbon Stocks and Fluxes in Tropical Lowland Dipterocarp Rainforests in Sabah, Malaysian Borneo

    Science.gov (United States)

    Saner, Philippe; Loh, Yen Yee; Ong, Robert C.; Hector, Andy

    2012-01-01

    Deforestation in the tropics is an important source of carbon C release to the atmosphere. To provide a sound scientific base for efforts taken to reduce emissions from deforestation and degradation (REDD+) good estimates of C stocks and fluxes are important. We present components of the C balance for selectively logged lowland tropical dipterocarp rainforest in the Malua Forest Reserve of Sabah, Malaysian Borneo. Total organic C in this area was 167.9 Mg C ha−1±3.8 (SD), including: Total aboveground (TAGC: 55%; 91.9 Mg C ha−1±2.9 SEM) and belowground carbon in trees (TBGC: 10%; 16.5 Mg C ha−1±0.5 SEM), deadwood (8%; 13.2 Mg C ha−1±3.5 SEM) and soil organic matter (SOM: 24%; 39.6 Mg C ha−1±0.9 SEM), understory vegetation (3%; 5.1 Mg C ha−1±1.7 SEM), standing litter (logging TAGC stocks were 28% lower compared to unlogged forest (128 Mg C ha−1±13.4 SEM); a combined weighted average mean reduction due to selective logging of −57.8 Mg C ha−1 (with 95% CI −75.5 to −40.2). Based on the findings we conclude that selective logging decreased the dipterocarp stock by 55–66%. Silvicultural treatments may have the potential to accelerate the recovery of dipterocarp C stocks to pre-logging levels. PMID:22235319

  9. Below- and above-ground controls on tree water use in lowland tropical forests

    Science.gov (United States)

    Meinzer, F. C.; Woodruff, D.; McCulloh, K.; Domec, J.

    2012-12-01

    Even in moist tropical forests, fluctuations in soil water availability and atmospheric evaporative demand can constrain tree water use. Our research in three lowland tropical forest sites in Panama over the past two decades has identified a series of tree biophysical and functional traits related to daily and seasonal patterns of uptake, transport and loss of water. Studies combining measurements of sap flow and natural abundance of hydrogen isotopes in soil and xylem water during the dry season show considerable variation in depth of soil water uptake among co-occurring species. Trees able to exploit progressively deeper sources of soil water during the dry season, as indicated by increasingly negative xylem water hydrogen isotope ratios, were also able to maintain constant or even increased rates of water use. Injections of a stable isotope tracer (deuterated water) into tree trunks revealed a considerable range of water transit and residence times among co-occurring, similarly-sized trees. Components of tree hydraulic architecture were also strong determinants of patterns of water use. Sapwood hydraulic capacitance, the amount of water released per unit change in tissue water potential, was a strong predictor of several tree water use and water relations traits, including sap velocity, water residence time, daily maximum branch xylem tension, and the time of day at which stomata began to increasingly restrict transpiration. Among early and late successional species, hydraulic traits such as trunk-to-branch tapering of xylem vessels, branch sap flux, branch sapwood specific conductivity and whole-tree leaf area-specific hydraulic conductance scaled uniformly with branch wood density. Consistent with differences in trunk-to-branch tapering of vessels between early and late successional species, the ratio of branch to trunk sap flux was substantially greater in early successional species. Among species, stomatal conductance and transpiration per unit leaf area

  10. In situ temperature relationships of biochemical and stomatal controls of photosynthesis in four lowland tropical tree species.

    Science.gov (United States)

    Slot, Martijn; Winter, Klaus

    2017-12-01

    Net photosynthetic carbon uptake of Panamanian lowland tropical forest species is typically optimal at 30-32 °C. The processes responsible for the decrease in photosynthesis at higher temperatures are not fully understood for tropical trees. We determined temperature responses of maximum rates of RuBP-carboxylation (V CMax ) and RuBP-regeneration (J Max ), stomatal conductance (G s ), and respiration in the light (R Light ) in situ for 4 lowland tropical tree species in Panama. G s had the lowest temperature optimum (T Opt ), similar to that of net photosynthesis, and photosynthesis became increasingly limited by stomatal conductance as temperature increased. J Max peaked at 34-37 °C and V CMax ~2 °C above that, except in the late-successional species Calophyllum longifolium, in which both peaked at ~33 °C. R Light significantly increased with increasing temperature, but simulations with a photosynthesis model indicated that this had only a small effect on net photosynthesis. We found no evidence for Rubisco-activase limitation of photosynthesis. T Opt of V CMax and J Max fell within the observed in situ leaf temperature range, but our study nonetheless suggests that net photosynthesis of tropical trees is more strongly influenced by the indirect effects of high temperature-for example, through elevated vapour pressure deficit and resulting decreases in stomatal conductance-than by direct temperature effects on photosynthetic biochemistry and respiration. © 2017 John Wiley & Sons Ltd.

  11. Landscape formation and soil genesis in volcanic parent materials in humid tropical lowlands of Costa Rica

    NARCIS (Netherlands)

    Nieuwenhuyse, A.

    1996-01-01


    The influence of volcanism on landscape genesis, and formation of soils on volcanic parent material was studied in the Atlantic lowland of Costs Rica. This lowland is a subduction basin of tectonic origin, in which thick alluvial and marine sediments are accumulated. At its southwestern

  12. Predation by Corallus annulatus (Boidae on Rhynchonycteris naso (Emballonuridae in a lowland tropical wet forest, Costa Rica

    Directory of Open Access Journals (Sweden)

    Lewis, Todd R.

    2009-11-01

    Full Text Available Corallus annulatus (Northern Annulated Tree-boa is a little-studied tropical Boid occurring disjunctively throughout Central America and tropical South America in mostly lowland tropical moist and wet forests (Holdridge, 1967; Stafford & Henderson, 1996; Smith & Acevedo, 1997; Henderson et al., 2001. Prior to this report and to the best of our knowledge, small rodents were the only documented prey for wild specimens of C. annulatus (Henderson et al., 1995. Caño Palma Biological Station is situated on the northeast coast of Costa Rica approximately 8 km north of Tortuguero. C. annulatus has previously been recorded from Manicaria forest at Caño Palma (Myers, 1990; Burger, 2001. On 12th January 2002 and 15th July 2003 we found two separate C. annulatus specimens with Rhynchonycteris naso (Proboscis bat in their stomachs.

  13. Carbon stocks and fluxes in tropical lowland dipterocarp rainforests in Sabah, Malaysian Borneo.

    Directory of Open Access Journals (Sweden)

    Philippe Saner

    Full Text Available Deforestation in the tropics is an important source of carbon C release to the atmosphere. To provide a sound scientific base for efforts taken to reduce emissions from deforestation and degradation (REDD+ good estimates of C stocks and fluxes are important. We present components of the C balance for selectively logged lowland tropical dipterocarp rainforest in the Malua Forest Reserve of Sabah, Malaysian Borneo. Total organic C in this area was 167.9 Mg C ha⁻¹±3.8 (SD, including: Total aboveground (TAGC: 55%; 91.9 Mg C ha⁻¹±2.9 SEM and belowground carbon in trees (TBGC: 10%; 16.5 Mg C ha⁻¹±0.5 SEM, deadwood (8%; 13.2 Mg C ha⁻¹±3.5 SEM and soil organic matter (SOM: 24%; 39.6 Mg C ha⁻¹±0.9 SEM, understory vegetation (3%; 5.1 Mg C ha⁻¹±1.7 SEM, standing litter (<1%; 0.7 Mg C ha⁻¹±0.1 SEM and fine root biomass (<1%; 0.9 Mg C ha⁻¹±0.1 SEM. Fluxes included litterfall, a proxy for leaf net primary productivity (4.9 Mg C ha⁻¹ yr⁻¹±0.1 SEM, and soil respiration, a measure for heterotrophic ecosystem respiration (28.6 Mg C ha⁻¹ yr⁻¹±1.2 SEM. The missing estimates necessary to close the C balance are wood net primary productivity and autotrophic respiration.Twenty-two years after logging TAGC stocks were 28% lower compared to unlogged forest (128 Mg C ha⁻¹±13.4 SEM; a combined weighted average mean reduction due to selective logging of -57.8 Mg C ha⁻¹ (with 95% CI -75.5 to -40.2. Based on the findings we conclude that selective logging decreased the dipterocarp stock by 55-66%. Silvicultural treatments may have the potential to accelerate the recovery of dipterocarp C stocks to pre-logging levels.

  14. Organic forms dominate hydrologic nitrogen export from a lowland tropical watershed.

    Science.gov (United States)

    Taylor, Philip G; Wieder, William R; Weintraub, Samantha; Cohen, Sagy; Cleveland, Cory C; Townsend, Alan R

    2015-05-01

    Observations of high dissolved inorganic nitrogen (DIN) concentrations in stream water have reinforced the notion that primary tropical rain forests cycle nitrogen (N) in relative excess compared to phosphorus. Here we test this notion by evaluating hydrologic N export from a small watershed on the Osa Peninsula, Costa Rica, where prior research has shown multiple indicators of conservative N cycling throughout the ecosystem. We repeatedly measured a host of factors known to influence N export for one year, including stream water chemistry and upslope litterfall, soil N availability and net N processing rates, and soil solution chemistry at the surface, 15- and 50-cm depths. Contrary to prevailing assumptions about the lowland N cycle, we find that dissolved organic nitrogen (DON) averaged 85% of dissolved N export for 48 of 52 consecutive weeks. For most of the year stream water nitrate (NO3-) export was very low, which reflected minimal net N processing and DIN leaching from upslope soils. Yet, for one month in the dry season, NO3- was the major component of N export due to a combination of low flows and upslope nitrification that concentrated NO3- in stream water. Particulate organic N (PON) export was much larger than dissolved forms at 14.6 kg N x ha(-1) x yr(-1), driven by soil erosion during storms. At this rate, PON export was slightly greater than estimated inputs from free-living N fixation and atmospheric N deposition, which suggests that erosion-driven PON export could constrain ecosystem level N stocks over longer timescales. This phenomenon is complimentary to the "DON leak" hypothesis, which postulates that the long-term accumulation of ecosystem N in unpolluted ecosystems is constrained by the export of organic N independently of biological N demand. Using an established global sediment generation model, we illustrate that PON erosion may be an important vector for N loss in tropical landscapes that are geomorphically active. This study supports an

  15. Soil biogeochemical and fungal patterns across a precipitation gradient in the lowland tropical rainforests of French Guiana

    Science.gov (United States)

    Soong, J.; Verbruggen, E.; Janssens, I.

    2016-12-01

    The Guyafor network contains over 12 pristine tropical rainforest long-term research sites throughout French Guiana, with a focus on vegetation and environmental monitoring at regular intervals. However, biogeochemical and belowground insights are needed to complete the picture of ecosystem functioning in these lowland tropical rainforests, which are critical to Earth's water and energy balance. Improving our biogeochemical understanding of these ecosystems is needed to improve Earth System Models, which poorly represent tropical systems. In July 2015 we sampled soils and litter from 12 of the Guyafor permanent plots in French Guiana spanning a mean annual precipitation gradient of over 2000 mm per year. We measured soil texture, pH, C, N and available P stocks in the top 30 cm, and fungal biodiversity using ITS DNA sequencing and characterized soil organic matter (SOM) C, N and P distribution among physically defined SOM fractions. We also measured litter layer standing stocks and CNP stoichiometry. We found significant stocks of SOM in the top 30 cm of the soil varying by a factor of 4 in the top 30 cm of soil with a negative correlation of arbuscular mycorrhizal fungi and soil C and N with available P. Available P was also a strong predictor of fungal community composition. Furthermore there is evidence for precipitation and mineralogical influences on leaf litter and SOM dynamics highlighting the importance of heterogeneity in tropical soil substrates and sub-climates in better understanding the biogeochemistry of tropical ecosystems.

  16. Characterization of land surface energy fluxes in a tropical lowland rice paddy

    Science.gov (United States)

    Chatterjee, Dibyendu; Tripathi, Rahul; Chatterjee, Sumanta; Debnath, Manish; Shahid, Mohammad; Bhattacharyya, Pratap; Swain, Chinmaya Kumar; Tripathy, Rojalin; Bhattacharya, Bimal K.; Nayak, Amaresh Kumar

    2018-04-01

    A field experiment was conducted in 2015 to study the land surface energy fluxes from tropical lowland rice paddy in eastern India with an objective to determine the mass, momentum, and energy exchange rates between rice paddies and the atmosphere. All the land surface energy fluxes were measured by eddy covariance (EC) system (make Campbell Scientific) in dry season (DS, 1-125 Julian days), dry fallow (DF, 126-181 Julian days), wet season (WS, 182-324 Julian days), and wet fallow (WF, 325-365 Julian days). The rice was cultivated in dry season (January-May) and wet season (July-November) in low wet lands and the ground is kept fallow during the remainder of the year. Results showed that albedo varied from 0.09 to 0.24 and showed positive value from morning 6:00 h until evening 18:00 h. Mean soil temperature (T g) was highest in DF, while the skin temperature (T s) was highest in WS. Average Bowen ratio (B) ranged from 0.21 to 0.64 and large variation in B was observed during the fallow periods as compared to the cropping seasons. The magnitude of aerodynamic, canopy, and climatological resistances increased with the progress of cropping season and their magnitudes decreased during the end of both cropping seasons and found minimum during the fallow periods. At a constant vapor pressure deficit (VPD) at 0.16, 0.18, 0.15, and 0.43 kPa, latent heat flux (LE) initially increased, but later it tended to level off with an increase in VPD. The actual evapotranspiration (ETa) during both the cropping seasons was higher than the fallow period. This study can be used as a source of default values for many land surface energy fluxes which are required in various meteorological or air-quality models for rice paddies. A larger imbalance of energy was observed during the wet season as the energy is stored and perhaps advected in the fresh water.

  17. Soilborne fungi have host affinity and host-specific effects on seed germination and survival in a lowland tropical forest.

    Science.gov (United States)

    Sarmiento, Carolina; Zalamea, Paul-Camilo; Dalling, James W; Davis, Adam S; Stump, Simon M; U'Ren, Jana M; Arnold, A Elizabeth

    2017-10-24

    The Janzen-Connell (JC) hypothesis provides a conceptual framework for explaining the maintenance of tree diversity in tropical forests. Its central tenet-that recruits experience high mortality near conspecifics and at high densities-assumes a degree of host specialization in interactions between plants and natural enemies. Studies confirming JC effects have focused primarily on spatial distributions of seedlings and saplings, leaving major knowledge gaps regarding the fate of seeds in soil and the specificity of the soilborne fungi that are their most important antagonists. Here we use a common garden experiment in a lowland tropical forest in Panama to show that communities of seed-infecting fungi are structured predominantly by plant species, with only minor influences of factors such as local soil type, forest characteristics, or time in soil (1-12 months). Inoculation experiments confirmed that fungi affected seed viability and germination in a host-specific manner and that effects on seed viability preceded seedling emergence. Seeds are critical components of reproduction for tropical trees, and the factors influencing their persistence, survival, and germination shape the populations of seedlings and saplings on which current perspectives regarding forest dynamics are based. Together these findings bring seed dynamics to light in the context of the JC hypothesis, implicating them directly in the processes that have emerged as critical for diversity maintenance in species-rich tropical forests.

  18. Cryptic diversity in Afro-tropical lowland forests: The systematics and biogeography of the avian genus Bleda.

    Science.gov (United States)

    Huntley, Jerry W; Voelker, Gary

    2016-06-01

    Recent investigations of distributional patterns of Afro-tropical lowland forest species have demonstrated to some degree our overall lack of understanding involving historical diversification patterns. Traditionally, researchers have relied upon two hypotheses, each of which views the lowland forest of Africa in differing roles. The Pleistocene Forest Refuge Hypothesis (PFRH) posits that biogeographic patterns of avian lowland species are explained via allopatric speciation during forest fragmentation cycles in the Pleistocene epoch (c. 1.8Ma-11,700Ka). The Montane Speciation Hypothesis (MSH) countered by suggesting that lowland forests are "evolutionary museums" where species, which originally evolved in montane forest refuge centers, remained without further diversification. Furthermore, investigations have largely regarded widespread, avian species which lack phenotypic variability as biogeographically "uninformative", with regards to historical biogeographic patterns. To test the tenets of these ideas, we investigated the systematics and biogeography of the genus Bleda, whose constituent species are restricted to lowland forest and are lacking in phenotypic variation. Using extracted DNA from 179 individuals, we amplified two mitochondrial genes and three nuclear loci and utilized Bayesian phylogenetic methods and molecular clock dating to develop a time-calibrated phylogeny of Bleda. We used LaGrange to develop an ancestral area reconstruction for the genus. Haplotype networks for three species were generated using Network. We recovered the four currently recognized species of Bleda, plus a monophyletic B. ugandae, a current sub-species which may warrant full species status. We found that the origins of the genus Bleda are estimated to be in the Upper Guinean forests of West Africa, dating to the Miocene (c. 7.5Ma), while the speciation events for the rest of the genus are dated to the Pliocene (c. 5-1.8Ma). Our analyses recovered discrete and highly

  19. Modelling the Carbon Stocks Estimation of the Tropical Lowland Dipterocarp Forest Using LIDAR and Remotely Sensed Data

    Science.gov (United States)

    Zaki, N. A. M.; Latif, Z. A.; Suratman, M. N.; Zainal, M. Z.

    2016-06-01

    Tropical forest embraces a large stock of carbon in the global carbon cycle and contributes to the enormous amount of above and below ground biomass. The carbon kept in the aboveground living biomass of trees is typically the largest pool and the most directly impacted by the anthropogenic factor such as deforestation and forest degradation. However, fewer studies had been proposed to model the carbon for tropical rain forest and the quantification still remain uncertainties. A multiple linear regression (MLR) is one of the methods to define the relationship between the field inventory measurements and the statistical extracted from the remotely sensed data which is LiDAR and WorldView-3 imagery (WV-3). This paper highlight the model development from fusion of multispectral WV-3 with the LIDAR metrics to model the carbon estimation of the tropical lowland Dipterocarp forest of the study area. The result shown the over segmentation and under segmentation value for this output is 0.19 and 0.11 respectively, thus D-value for the classification is 0.19 which is 81%. Overall, this study produce a significant correlation coefficient (r) between Crown projection area (CPA) and Carbon stocks (CS); height from LiDAR (H_LDR) and Carbon stocks (CS); and Crown projection area (CPA) and height from LiDAR (H_LDR) were shown 0.671, 0.709 and 0.549 respectively. The CPA of the segmentation found to be representative spatially with higher correlation of relationship between diameter at the breast height (DBH) and carbon stocks which is Pearson Correlation p = 0.000 (p using multiple linear regression method. The study concluded that the integration of WV-3 imagery with the CHM raster based LiDAR were useful in order to quantify the AGB and carbon stocks for a larger sample area of the Lowland Dipterocarp forest.

  20. Relationships between Community Level Functional Traits of Trees and Seedlings during Secondary Succession in a Tropical Lowland Rainforest.

    Science.gov (United States)

    Lu, XingHui; Zang, RunGuo; Huang, JiHong

    2015-01-01

    Most of the previous studies on functional traits focus exclusively on either seedlings or trees. Little knowledge exists on the relationships between community level functional traits of trees and seedlings during succession. Here, we examine variations of the community-level functional traits for trees and seedlings and their correlations along a secondary successional and environmental gradient in a tropical lowland rainforest after shifting cultivation. The results showed that the dynamic patterns in community level functional traits of seedlings were generally consistent with those of the trees during secondary succession. Compared with seedlings, community level traits for trees were less affected by abiotic factors during secondary succession. Correlations between community level functional traits of trees and seedlings were significant for: leaf dry matter content and leaf nitrogen concentration in the 18-year-old fallow; leaf chlorophyll content in the 30-year-old fallow; specific leaf area, leaf dry matter content and leaf nitrogen concentration in the 60-year-old fallow; and leaf nitrogen concentration in old growth. However, these traits except specific leaf area for the tree and seedling communities were all significantly correlated if all the successional stages were combined. Our results suggest that the correlations between community level functional traits of trees and those of seedlings depend on the actual traits and the successional stages examined. However, if all the four successional stages are combined, then four out of five of the community level functional traits for trees could be well predicted by those of the seedlings in the tropical lowland rain forest.

  1. Degradation of Root Community Traits as Indicator for Transformation of Tropical Lowland Rain Forests into Oil Palm and Rubber Plantations.

    Science.gov (United States)

    Sahner, Josephine; Budi, Sri Wilarso; Barus, Henry; Edy, Nur; Meyer, Marike; Corre, Marife D; Polle, Andrea

    2015-01-01

    Conversion of tropical forests into intensely managed plantations is a threat to ecosystem functions. On Sumatra, Indonesia, oil palm (Elaeis guineensis) plantations are rapidly expanding, displacing rain forests and extensively used rubber (Hevea brasiliensis) agro-forests. Here, we tested the influence of land use systems on root traits including chemical traits (carbon, nitrogen, mineral nutrients, potentially toxic elements [aluminium, iron] and performance traits (root mass, vitality, mycorrhizal colonization). Traits were measured as root community-weighed traits (RCWTs) in lowland rain forests, in rubber agro-forests mixed with rain forest trees, in rubber and oil palm plantations in two landscapes (Bukit Duabelas and Harapan, Sumatra). We hypothesized that RCWTs vary with land use system indicating increasing transformation intensity and loss of ecosystem functions. The main factors found to be related to increasing transformation intensity were declining root vitality and root sulfur, nitrogen, carbon, manganese concentrations and increasing root aluminium and iron concentrations as well as increasing spore densities of arbuscular mycorrhizas. Mycorrhizal abundance was high for arbuscular and low for ectomycorrhizas and unrelated to changes in RCWTs. The decline in RCWTs showed significant correlations with soil nitrogen, soil pH and litter carbon. Thus, our study uncovered a relationship between deteriorating root community traits and loss of ecosystem functionality and showed that increasing transformation intensity resulted in decreasing root nutrition and health. Based on these results we suggest that land management that improves root vitality may enhance the ecological functions of intense tropical production systems.

  2. Wild pigs (Sus scrofa) mediate large-scale edge effects in a lowland tropical rainforest in Peninsular Malaysia.

    Science.gov (United States)

    Fujinuma, Junichi; Harrison, Rhett D

    2012-01-01

    Edge-effects greatly extend the area of tropical forests degraded through human activities. At Pasoh, Peninsular Malaysia, it has been suggested that soil disturbance by highly abundant wild pigs (Sus scrofa), which feed in adjacent Oil Palm plantations, may have mediated the invasion of Clidemia hirta (Melastomataceae) into the diverse tropical lowland rain forest. To investigate this hypothesis, we established three 1 km transects from the forest/Oil Palm plantation boundary into the forest interior. We recorded the distribution of soil disturbance by wild pigs, C. hirta abundance, and environmental variables. These data were analyzed using a hierarchical Bayesian model that incorporated spatial auto-correlation in the environmental variables. As predicted, soil disturbance by wild pigs declined with distance from forest edge and C. hirta abundance was correlated with the level of soil disturbance. Importantly there was no effect of distance on C. hirta abundance, after controlling for the effect of soil disturbance. Clidemia hirta abundance was also correlated with the presence of canopy openings, but there was no significant association between the occurrence of canopy openings and distance from the edge. Increased levels of soil disturbance and C. hirta abundance were still detectable approximately 1 km from the edge, demonstrating the potential for exceptionally large-scale animal mediated edge effects.

  3. Soil trace gas fluxes along orthogonal precipitation and soil fertility gradients in tropical lowland forests of Panama

    Directory of Open Access Journals (Sweden)

    A. L. Matson

    2017-07-01

    Full Text Available Tropical lowland forest soils are significant sources and sinks of trace gases. In order to model soil trace gas flux for future climate scenarios, it is necessary to be able to predict changes in soil trace gas fluxes along natural gradients of soil fertility and climatic characteristics. We quantified trace gas fluxes in lowland forest soils at five locations in Panama, which encompassed orthogonal precipitation and soil fertility gradients. Soil trace gas fluxes were measured monthly for 1 (NO or 2 (CO2, CH4, N2O years (2010–2012 using vented dynamic (for NO only or static chambers with permanent bases. Across the five sites, annual fluxes ranged from 8.0 to 10.2 Mg CO2-C, −2.0 to −0.3 kg CH4-C, 0.4 to 1.3 kg N2O-N and −0.82 to −0.03 kg NO-N ha−1 yr−1. Soil CO2 emissions did not differ across sites, but they did exhibit clear seasonal differences and a parabolic pattern with soil moisture across sites. All sites were CH4 sinks; within-site fluxes were largely controlled by soil moisture, whereas fluxes across sites were positively correlated with an integrated index of soil fertility. Soil N2O fluxes were low throughout the measurement years, but the highest emissions occurred at a mid-precipitation site with high soil N availability. Net negative NO fluxes at the soil surface occurred at all sites, with the most negative fluxes at the low-precipitation site closest to Panama City; this was likely due to high ambient NO concentrations from anthropogenic sources. Our study highlights the importance of both short-term (climatic and long-term (soil and site characteristics factors in predicting soil trace gas fluxes.

  4. MODELLING THE CARBON STOCKS ESTIMATION OF THE TROPICAL LOWLAND DIPTEROCARP FOREST USING LIDAR AND REMOTELY SENSED DATA

    Directory of Open Access Journals (Sweden)

    N. A. M. Zaki

    2016-06-01

    Full Text Available Tropical forest embraces a large stock of carbon in the global carbon cycle and contributes to the enormous amount of above and below ground biomass. The carbon kept in the aboveground living biomass of trees is typically the largest pool and the most directly impacted by the anthropogenic factor such as deforestation and forest degradation. However, fewer studies had been proposed to model the carbon for tropical rain forest and the quantification still remain uncertainties. A multiple linear regression (MLR is one of the methods to define the relationship between the field inventory measurements and the statistical extracted from the remotely sensed data which is LiDAR and WorldView-3 imagery (WV-3. This paper highlight the model development from fusion of multispectral WV-3 with the LIDAR metrics to model the carbon estimation of the tropical lowland Dipterocarp forest of the study area. The result shown the over segmentation and under segmentation value for this output is 0.19 and 0.11 respectively, thus D-value for the classification is 0.19 which is 81%. Overall, this study produce a significant correlation coefficient (r between Crown projection area (CPA and Carbon stocks (CS; height from LiDAR (H_LDR and Carbon stocks (CS; and Crown projection area (CPA and height from LiDAR (H_LDR were shown 0.671, 0.709 and 0.549 respectively. The CPA of the segmentation found to be representative spatially with higher correlation of relationship between diameter at the breast height (DBH and carbon stocks which is Pearson Correlation p = 0.000 (p Dipterocarp forest.

  5. Shaping forest safety nets with markets: Adaptation to climate change under changing roles of tropical forests in Congo Basin

    International Nuclear Information System (INIS)

    Nkem, Johnson; Kalame, Fobissie B.; Idinoba, Monica; Somorin, Olufunso A.; Ndoye, Ousseynou; Awono, Abdon

    2010-01-01

    Tropical forests hold several goods and services used by forest-dependent people as safety nets to traverse difficult periods of resource supply. These same goods and services are constantly surrounded by emerging markets linking remote communities with major urban centers nationally and internationally. How these markets affect adaptation remains unclear. This paper examines the roles of markets in non-timber forest products that normally serve as safety nets for forest communities, and the implications for climate change adaptation in the Congo Basin. Following the identification and prioritization of forest-based development sectors for adaptation by stakeholders, the types of markets and trades surrounding the identified sectors were examined in two provinces in the Democratic Republic of Congo as a case study in order to evaluate revenue flows and their potential contribution to adaptation by local communities. The distribution of the market revenue leaves local people with returns much lower than the worth of the commodity, while wholesalers and retailers reap most of the benefits and profit from the high variability in volume and market earnings for the same commodity across provinces. Markets may increase the value of a commodity as observed in this study, but their contributions to adaptation appear highly limited for local communities following their distribution among the stakeholders in the market chain. This is likely to be worse in free market settings, especially when it diminishes the safety net roles of forest goods and services. Markets should therefore complement rather than substitute forests roles for adaptation to climate change in tropical forest countries. Capturing the benefits of trade for adaptation is crucial but will require policy reforms and further research that addresses the complexity in benefit sharing.

  6. Genetic structure of the threatened Dipterocarpus costatus populations in lowland tropical rainforests of southern Vietnam.

    Science.gov (United States)

    Duc, N M; Duy, V D; Xuan, B T T; Thang, B V; Ha, N T H; Tam, N M

    2016-10-24

    Dipterocarpus costatus is an endangered species restricted to the lowland forests of southern Vietnam. Habitat loss and over-exploitation of D. costatus wood are the major threats to this species. We investigated the level of genetic variability within and among populations of D. costatus in order to provide guidelines for the conservation, management, and restoration of this species to the Forest Protection Department, Vietnam. Nine microsatellite markers were used to analyze 114 samples from four populations representing the natural range of D. costatus in southeast Vietnam. We indicated the low allelic diversity (N A = 2.3) and low genetic diversities with an average observed and expected heterozygosity of 0.130 and 0.151, respectively, in the lowland forests of southeast Vietnam. The low genetic diversity might be a consequence of inbreeding within the small and isolated populations of D. costatus owing to its habitat loss and over-exploitation. All populations deviated from Hardy-Weinberg equilibrium showing reduced heterozygosity. Alleles were lost from the populations by genetic drift. Genetic differentiation among populations was high (average pairwise F ST = 0.405), indicating low gene flow (<1) and isolated populations due to its destructed habitat and large geographical distances (P < 0.05) among populations. Heterozygosity excess tests (except of Bu Gia Map only under infinite allele model) were negative. The high genetic variation (62.7%) was found within populations. The STRUCTURE and neighbor joining tree results suggest strong differentiation among D. costatus populations, with the three genetic clusters, Phu Quoc, Tan Phu and Bu Gia Map, and Lo Go-Xa Mat due to habitat fragmentation and isolation. The threatened status of D. costatus was related to a lack of genetic diversity, with all its populations isolated in small forest patches. We recommend the establishment of an ex situ conservation site for D. costatus with a new big population comprising

  7. Impacts of logging and hunting on western lowland gorilla (Gorilla gorilla gorilla) populations and consequences for forest regeneration. A review

    OpenAIRE

    Haurez, B.; Petre, CA.; Doucet, JL.

    2013-01-01

    Timber exploitation is rapidly expanding throughout the Congo Basin. Forest areas assigned to timber harvesting have sharply expanded over the decades and logging concessions now largely overlap with the range of western lowland gorilla (Gorilla gorilla gorilla Savage & Wyman, 1847). However this species, which is considered as critically endangered by IUCN, could play an essential role in maintaining the structure and composition of tropical rainforest notably through seed dispersal services...

  8. Modelling rainfall interception by a lowland tropical rain forest in northeastern Puerto Rico.

    NARCIS (Netherlands)

    Schellekens, J.; Scatena, F.N.; Bruijnzeel, L.A.; Wickel, A.J.

    1999-01-01

    Recent surveys of tropical forest water use suggest that rainfall interception by the canopy is largest in wet maritime locations. To investigate the underlying processes at one such location-the Luquillo Experimental Forest in eastern Puerto Rico-66 days of detailed throughfall and above-canopy

  9. Large trees drive forest aboveground biomass variation in moist lowland forests across the tropics

    NARCIS (Netherlands)

    Slik, J.W.F.; Paoli, G.; McGuire, K.; Amaral, I.; Barroso, J.; Bongers, F.; Poorter, L.

    2013-01-01

    Aim - Large trees (d.b.h.¿=¿70¿cm) store large amounts of biomass. Several studies suggest that large trees may be vulnerable to changing climate, potentially leading to declining forest biomass storage. Here we determine the importance of large trees for tropical forest biomass storage and explore

  10. Fine root dynamics and trace gas fluxes in two lowland tropical forest soils.

    Science.gov (United States)

    WHENDEE L. SILVER; ANDREW W. THOMPSON; MEGAN E . MCGRODDY; RUTH K. VARNER; JADSON D. DIAS; HUDSON SILVA; CRILL PATRICK M.; MICHAEL KELLER

    2005-01-01

    Fine root dynamics have the potential to contribute significantly to ecosystem-scale biogeochemical cycling, including the production and emission of greenhouse gases. This is particularly true in tropical forests which are often characterized as having large fine root biomass and rapid rates of root production and decomposition. We examined patterns in fine root...

  11. Large trees drive forest aboveground biomass variation in moist lowland forests across the tropics

    DEFF Research Database (Denmark)

    Slik, J.W.Ferry; Paoli, Gary; McGuire, Krista

    2013-01-01

    .3 ± 109.3 Mg ha−1). Pan-tropical variation in density of large trees and AGB was associated with soil coarseness (negative), soil fertility (positive), community wood density (positive) and dominance of wind dispersed species (positive), temperature in the coldest month (negative), temperature...

  12. Restoration Ecology of Lowland tropical Peatlands in Southeast Asia: Current Knowledge and Future Research Directions

    NARCIS (Netherlands)

    Page, S.; Hoscilo, A.; Wösten, J.H.M.; Jauhiainen, J.; Silvius, M.J.; Rieley, J.; Ritzema, H.P.; Tansey, K.; Graham, L.; Vasander, H.; Limin, S.

    2009-01-01

    Studies of restoration ecology are well established for northern peatlands, but at an early stage for tropical peatlands. Extensive peatland areas in Southeast Asia have been degraded through deforestation, drainage and fire, leading to on- and off-site environmental and socio-economic impacts of

  13. Quantifying above- and belowground biomass carbon loss with forest conversion in tropical lowlands of Sumatra (Indonesia).

    Science.gov (United States)

    Kotowska, Martyna M; Leuschner, Christoph; Triadiati, Triadiati; Meriem, Selis; Hertel, Dietrich

    2015-10-01

    Natural forests in South-East Asia have been extensively converted into other land-use systems in the past decades and still show high deforestation rates. Historically, lowland forests have been converted into rubber forests, but more recently, the dominant conversion is into oil palm plantations. While it is expected that the large-scale conversion has strong effects on the carbon cycle, detailed studies quantifying carbon pools and total net primary production (NPPtotal ) in above- and belowground tree biomass in land-use systems replacing rainforest (incl. oil palm plantations) are rare so far. We measured above- and belowground carbon pools in tree biomass together with NPPtotal in natural old-growth forests, 'jungle rubber' agroforests under natural tree cover, and rubber and oil palm monocultures in Sumatra. In total, 32 stands (eight plot replicates per land-use system) were studied in two different regions. Total tree biomass in the natural forest (mean: 384 Mg ha(-1) ) was more than two times higher than in jungle rubber stands (147 Mg ha(-1) ) and >four times higher than in monoculture rubber and oil palm plantations (78 and 50 Mg ha(-1) ). NPPtotal was higher in the natural forest (24 Mg ha(-1)  yr(-1) ) than in the rubber systems (20 and 15 Mg ha(-1)  yr(-1) ), but was highest in the oil palm system (33 Mg ha(-1)  yr(-1) ) due to very high fruit production (15-20 Mg ha(-1)  yr(-1) ). NPPtotal was dominated in all systems by aboveground production, but belowground productivity was significantly higher in the natural forest and jungle rubber than in plantations. We conclude that conversion of natural lowland forest into different agricultural systems leads to a strong reduction not only in the biomass carbon pool (up to 166 Mg C ha(-1) ) but also in carbon sequestration as carbon residence time (i.e. biomass-C:NPP-C) was 3-10 times higher in the natural forest than in rubber and oil palm plantations. © 2015 John Wiley & Sons Ltd.

  14. Organismic-Scale Remote Sensing of Canopy Foliar Traits in Lowland Tropical Forests

    Directory of Open Access Journals (Sweden)

    K. Dana Chadwick

    2016-01-01

    Full Text Available Airborne high fidelity imaging spectroscopy (HiFIS holds great promise for bridging the gap between field studies of functional diversity, which are spatially limited, and satellite detection of ecosystem properties, which lacks resolution to understand within landscape dynamics. We use Carnegie Airborne Observatory HiFIS data combined with field collected foliar trait data to develop quantitative prediction models of foliar traits at the tree-crown level across over 1000 ha of humid tropical forest. We predicted foliar leaf mass per area (LMA as well as foliar concentrations of nitrogen, phosphorus, calcium, magnesium and potassium for canopy emergent trees (R2: 0.45–0.67, relative RMSE: 11%–14%. Correlations between remotely sensed model coefficients for these foliar traits are similar to those found in laboratory studies, suggesting that the detection of these mineral nutrients is possible through their biochemical stoichiometry. Maps derived from HiFIS provide quantitative foliar trait information across a tropical forest landscape at fine spatial resolution, and along environmental gradients. Multi-nutrient maps implemented at the fine organismic scale will subsequently provide new insight to the functional biogeography and biological diversity of tropical forest ecosystems.

  15. Heart rate reveals torpor at high body temperatures in lowland tropical free-tailed bats.

    Science.gov (United States)

    O'Mara, M Teague; Rikker, Sebastian; Wikelski, Martin; Ter Maat, Andries; Pollock, Henry S; Dechmann, Dina K N

    2017-12-01

    Reduction in metabolic rate and body temperature is a common strategy for small endotherms to save energy. The daily reduction in metabolic rate and heterothermy, or torpor, is particularly pronounced in regions with a large variation in daily ambient temperature. This applies most strongly in temperate bat species (order Chiroptera), but it is less clear how tropical bats save energy if ambient temperatures remain high. However, many subtropical and tropical species use some daily heterothermy on cool days. We recorded the heart rate and the body temperature of free-ranging Pallas' mastiff bats ( Molossus molossus ) in Gamboa, Panamá, and showed that these individuals have low field metabolic rates across a wide range of body temperatures that conform to high ambient temperature. Importantly, low metabolic rates in controlled respirometry trials were best predicted by heart rate, and not body temperature . Molossus molossus enter torpor-like states characterized by low metabolic rate and heart rates at body temperatures of 32°C, and thermoconform across a range of temperatures. Flexible metabolic strategies may be far more common in tropical endotherms than currently known.

  16. Assessing tropical rainforest growth traits: Data - Model fusion in the Congo basin and beyond

    Science.gov (United States)

    Pietsch, Stephan

    2017-04-01

    Virgin forest ecosystems resemble the key reference level for natural tree growth dynamics. The mosaic cycle concept describes such dynamics as local disequilibria driven by patch level succession cycles of breakdown, regeneration, juvenescence and old growth. These cycles, however, may involve different traits of light demanding and shade tolerant species assemblies. In this work a data model fusion concept will be introduced to assess the differences in growth dynamics of the mosaic cycle of the Western Congolian Lowland Rainforest ecosystem. Field data from 34 forest patches located in an ice age forest refuge, recently pinpointed to the ground and still devoid of direct human impact up to today - resemble the data base. A 3D error assessment procedure versus BGC model simulations for the 34 patches revealed two different growth dynamics, consistent with observed growth traits of pioneer and late succession species assemblies of the Western Congolian Lowland rainforest. An application of the same procedure to Central American Pacific rainforests confirms the strength of the 3D error field data model fusion concept to Central American Pacific rainforests confirms the strength of the 3D error field data model fusion concept to assess different growth traits of the mosaic cycle of natural forest dynamics.

  17. Taxonomic identity determines N2 fixation by canopy trees across lowland tropical forests.

    Science.gov (United States)

    Wurzburger, Nina; Hedin, Lars O

    2016-01-01

    Legumes capable of fixing atmospheric N2 are abundant and diverse in many tropical forests, but the factors determining ecological patterns in fixation are unresolved. A long-standing idea is that fixation depends on soil nutrients (N, P or Mo), but recent evidence shows that fixation may also differ among N2-fixing species. We sampled canopy-height trees across five species and one species group of N2-fixers along a landscape P gradient, and manipulated P and Mo to seedlings in a shadehouse. Our results identify taxonomy as the major determinant of fixation, with P (and possibly Mo) only influencing fixation following tree-fall disturbances. While 44% of trees did not fix N2, other trees fixed at high rates, with two species functioning as superfixers across the landscape. Our results raise the possibility that fixation is determined by biodiversity, evolutionary history and species-specific traits (tree growth rate, canopy stature and response to disturbance) in the tropical biome. © 2015 John Wiley & Sons Ltd/CNRS.

  18. Deep divergences and extensive phylogeographic structure in a clade of lowland tropical salamanders

    Directory of Open Access Journals (Sweden)

    Rovito Sean M

    2012-12-01

    Full Text Available Abstract Background The complex geological history of Mesoamerica provides the opportunity to study the impact of multiple biogeographic barriers on population differentiation. We examine phylogeographic patterns in a clade of lowland salamanders (Bolitoglossa subgenus Nanotriton using two mitochondrial genes and one nuclear gene. We use several phylogeographic analyses to infer the history of this clade and test hypotheses regarding the geographic origin of species and location of genetic breaks within species. We compare our results to those for other taxa to determine if historical events impacted different species in a similar manner. Results Deep genetic divergence between species indicates that they are relatively old, and two of the three widespread species show strong phylogeographic structure. Comparison of mtDNA and nuclear gene trees shows no evidence of hybridization or introgression between species. Isolated populations of Bolitoglossa rufescens from Los Tuxtlas region constitute a separate lineage based on molecular data and morphology, and divergence between Los Tuxtlas and other areas appears to predate the arrival of B. rufescens in other areas west of the Isthmus of Tehuantepec. The Isthmus appears responsible for Pliocene vicariance within B. rufescens, as has been shown for other taxa. The Motagua-Polochic fault system does not appear to have caused population vicariance, unlike in other systems. Conclusions Species of Nanotriton have responded to some major geological events in the same manner as other taxa, particularly in the case of the Isthmus of Tehuantepec. The deep divergence of the Los Tuxtlas populations of B. rufescens from other populations highlights the contribution of this volcanic system to patterns of regional endemism, and morphological differences observed in the Los Tuxtlas populations suggests that they may represent an undescribed species of Bolitoglossa. The absence of phylogeographic structure in B

  19. Root Hydraulics and Root Sap Flow in a Panamanian Low-Land Tropical Forest

    Science.gov (United States)

    Bretfeld, M.; Ewers, B. E.; Hall, J. S.; Ogden, F. L.; Beverly, D.; Speckman, H. N.

    2017-12-01

    In the tropics, trees are subjected to increasingly frequent and severe droughts driven by climate change. Given the hydrological benefits associated with tropical forests, such as reduced peak runoff during high precipitation events and increased base flow during drought periods ("sponge-effect"), the underlying plant-hydrological processes at the soil-plant interface have become the focus of recent research efforts. In Panama, the 2015/16 El Niño-Southern Oscillation (ENSO) event ranks amongst the driest and hottest periods on record, thus providing an excellent opportunity to study the effects of drought on tropical forests. Starting in 2015, we instrumented 76 trees with heat-ratio sap flow sensors in regrowing secondary forest (8-, 25-, and 80-year old stands) in the 15 km2 Agua Salud study area, located in central Panama. Of those trees, 16 individuals were instrumented with additional sap flow sensors on three roots each. Data were logged every 30 minutes and soil moisture was measured at 10, 30, 50, and 100 cm depth. Meteorological data were taken from a nearby met-station. Rooting depth and root density were assessed in eight 2×2×2 m soil pits. In April 2017, we measured hydraulic conductance and vulnerability to cavitation of eight species using the centrifuge technique. Trees in 8-year old forest limited transpiration during the drought whereas no such limitation was evident in trees of the 80-year old forest. Root sap flow data show seasonal shifts in water uptake between individual roots of a given tree, with sap flow decreasing in some roots while simultaneously increasing in other roots during the wet-dry season transition. Roots followed a typical log distribution along the profile, with overall root densities of 46, 43, and 52 roots m-2 in the 8-, 25-, and 80-yo stand, respectively. Roots were found up to 200 cm depth in all forests, with roots >5 cm occurring at lower depths (>125 cm) only in 25- and 80-year old forests. Maximum hydraulic

  20. In tropical lowland rain forests monocots have tougher leaves than dicots, and include a new kind of tough leaf.

    Science.gov (United States)

    Dominy, Nathaniel J; Grubb, Peter J; Jackson, Robyn V; Lucas, Peter W; Metcalfe, Daniel J; Svenning, Jens-Christian; Turner, Ian M

    2008-06-01

    There has been little previous work on the toughness of the laminae of monocots in tropical lowland rain forest (TLRF) despite the potential importance of greater toughness in inhibiting herbivory by invertebrates. Of 15 monocot families with >100 species in TLRF, eight have notably high densities of fibres in the lamina so that high values for toughness are expected. In north-eastern Australia punch strength was determined with a penetrometer for both immature leaves (approx. 30 % final area on average) and fully expanded, fully toughened leaves. In Singapore and Panama, fracture toughness was determined with an automated scissors apparatus using fully toughened leaves only. In Australia punch strength was, on average, 7x greater in shade-tolerant monocots than in neighbouring dicots at the immature stage, and 3x greater at the mature stage. In Singapore, shade-tolerant monocots had, on average, 1.3x higher values for fracture toughness than neighbouring dicots. In Panama, both shade-tolerant and gap-demanding monocots were tested; they did not differ in fracture toughness. The monocots had markedly higher values than the dicots whether shade-tolerant or gap-demanding species were considered. It is predicted that monocots will be found to experience lower rates of herbivory by invertebrates than dicots. The tough monocot leaves include both stiff leaves containing relatively little water at saturation (e.g. palms), and leaves which lack stiffness, are rich in water at saturation and roll readily during dry weather or even in bright sun around midday (e.g. gingers, heliconias and marants). Monocot leaves also show that it is possible for leaves to be notably tough throughout the expansion phase of development, something never recorded for dicots. The need to broaden the botanist's mental picture of a 'tough leaf' is emphasized.

  1. Modelling rainfall interception by a lowland tropical rain forest in northeastern Puerto Rico

    Science.gov (United States)

    Schellekens, J.; Scatena, F. N.; Bruijnzeel, L. A.; Wickel, A. J.

    1999-12-01

    Recent surveys of tropical forest water use suggest that rainfall interception by the canopy is largest in wet maritime locations. To investigate the underlying processes at one such location—the Luquillo Experimental Forest in eastern Puerto Rico—66 days of detailed throughfall and above-canopy climatic data were collected in 1996 and analysed using the Rutter and Gash models of rainfall interception. Throughfall occurred on 80% of the days distributed over 80 rainfall events. Measured interception loss was 50% of gross precipitation. When Penman-Monteith based estimates for the wet canopy evaporation rate (0.11 mm h -1 on average) and a canopy storage of 1.15 mm were used, both models severely underestimated measured interception loss. A detailed analysis of four storms using the Rutter model showed that optimizing the model for the wet canopy evaporation component yielded much better results than increasing the canopy storage capacity. However, the Rutter model failed to properly estimate throughfall amounts during an exceptionally large event. The analytical model, on the other hand, was capable of representing interception during the extreme event, but once again optimizing wet canopy evaporation rates produced a much better fit than optimizing the canopy storage capacity. As such, the present results support the idea that it is primarily a high rate of evaporation from a wet canopy that is responsible for the observed high interception losses.

  2. Multi-Temporal Interferometry to Investigate Landslide Dynamics in a Tropical Urban Environment: Focus on Bukavu (DR Congo)

    Science.gov (United States)

    Monsieurs, E.; Dille, A.; Nobile, A.; d'Oreye, N.; Kervyn, F.; Dewitte, O.

    2017-12-01

    Landslides can lead to high impacts in less developed countries, particularly in some urban tropical environments where a combination of intense rainfall, active tectonics, steep topography and high population density can be found. However, the processes controlling landslides initiation and their evolution through time remains poorly understood. Here we show the relevance of the use of multi-temporal differential SAR interferometry (DInSAR) to characterize ground deformations associated to landslides in the rapidly expanding city of Bukavu (DR Congo). A series of 70 COSMO-SkyMed SAR images acquired between March 2015 and April 2016 with a mean revisiting time of 8 days were used to produce displacement rate maps and ground deformation time series using the Small Baseline Subset approach. Results show that various landslide processes of different ages, mechanisms and state of activity can be identified across Bukavu city. InSAR ground deformation maps reveal for instance the complexity of a large (1.5 km²) active slide affecting a densely inhabited slum neighbourhood and characterized by the presence of sectors moving at different rates (ranging from 10 mm/yr up to 75 mm/yr in LOS direction). The evaluation of the ground deformations captured by DInSAR through a two-step validation procedure combining Differential GPS measurements and field observations attested the reliability of the measurements as well as the capability of the technique to grasp the deformation pattern affecting this complex tropical-urban environment. However, longer time series will be needed to infer landside response to climate, seismic and anthropogenic activities.

  3. Multi-temporal InSAR monitoring of landslides in a tropical urban environment: focus on Bukavu (DR Congo)

    Science.gov (United States)

    Nobile, Adriano; Monsieurs, Elise; Dewitte, Olivier; d'Oreyes, Nicolas; Kervyn, Francois

    2016-04-01

    The western branch of the East African Rift System, in Central Africa, is characterized by the presence of several geohazards: earthquakes, volcanoes, and landslides. Every year, landslides cause fatalities, structural and functional damage to infrastructure and private properties with serious disruptions of the organization of societies and severe impact on the populations. These impacts are particularly important in the city of Bukavu (DR Congo) located within the Rift, on the southern shore of Lake Kivu. Large slow-moving landslides continuously affect highly populated slopes in the city. However little is known about their actual kinematics and the processes at play. Here we use multi-temporal InSAR technique to monitor these ground deformations. Using 50 Cosmo-SkyMed SAR images, acquired between March - October 2015 with a revisiting time of 8 days (ascending and descending orbits), we produce displacement-rate maps and ground deformation time series using the PS technique. Movements with a velocity >5cm/yr are detected, which is consistent with field observations. DGPS measurements, taken at 21 benchmarks in the area during the same period, allow validating the results. Similar ground deformation rates are found for the period 2002-2008 using Envisat ASAR images. Furthermore, comparison with rainfall monitoring data acquire on site should help us to understand the influence of water and the tropical seasonality in the slide mechanisms.

  4. Water use in four model tropical plant associations established in the lowlands of Costa Rica

    Directory of Open Access Journals (Sweden)

    Marco V Gutiérrez-Soto

    2008-12-01

    Full Text Available We examined soil water use patterns of four model plant associations established in the North Caribbean lowlands of Costa Rica by comparing the stable hydrogen isotope composition, δD, in xylem sap and in soil water at different depths, under rainy and dry conditions. Four 5-year-old model plant associations composed of 2 tree species (Hyeronima alchorneoides and Cedrela odorata having different architecture and phenology were studied. Average tree height was 8.9 and 7.6 m, respectively. Each tree species was grown in monoculture and in polyculture with 2 perennial monocotyledons (Euterpe oleracea and Heliconia imbricata. Maximum rooting depth at the time of δD determination was ~ 2 m for almost all species. Most roots of all species were concentrated in the upper soil layers. Stomatal conductance to water vapor (gS was higher in the deciduous C. odorata than in the evergreen H. alchorneoides; within each species, gS did not differ when the trees were grown in mono or in polyculture. During the rainy season, gradients in soil water δD were not observed. Average rainy season xylem sap δD did not differ among members of the plant combinations tested (-30 ‰, and was more similar to δD values of shallow soil water. Under dry conditions, volumetric soil water content declined from 50 to ~ 35%, and modest gradients in soil water δD were observed. xylem sap δD obtained during dry conditions was significantly lower than rainy season values. xylem sap δD of plants growing in the four associations varied between -9 and -22‰, indicating that shallow water was predominantly absorbed during the dry period too. Differences in xylem sap δD of trees and monocots were also detected, but no significant patterns emerged. The results suggest that: a the plant associations examined extracted water predominantly from shallow soil layers (Examinamos los patrones de uso de agua del suelo de cuatro asociaciones vegetales establecidas en el Caribe norte de

  5. Earthworms and tree roots: A model study of the effect of preferential flow paths on runoff generation and groundwater recharge in steep, saprolitic, tropical lowland catchments

    Science.gov (United States)

    Cheng, Yanyan; Ogden, Fred L.; Zhu, Jianting

    2017-07-01

    Preferential flow paths (PFPs) affect the hydrological response of humid tropical catchments but have not received sufficient attention. We consider PFPs created by tree roots and earthworms in a near-surface soil layer in steep, humid, tropical lowland catchments and hypothesize that observed hydrological behaviors can be better captured by reasonably considering PFPs in this layer. We test this hypothesis by evaluating the performance of four different physically based distributed model structures without and with PFPs in different configurations. Model structures are tested both quantitatively and qualitatively using hydrological, geophysical, and geochemical data both from the Smithsonian Tropical Research Institute Agua Salud Project experimental catchment(s) in Central Panama and other sources in the literature. The performance of different model structures is evaluated using runoff Volume Error and three Nash-Sutcliffe efficiency measures against observed total runoff, stormflows, and base flows along with visual comparison of simulated and observed hydrographs. Two of the four proposed model structures which include both lateral and vertical PFPs are plausible, but the one with explicit simulation of PFPs performs the best. A small number of vertical PFPs that fully extend below the root zone allow the model to reasonably simulate deep groundwater recharge, which plays a crucial role in base flow generation. Results also show that the shallow lateral PFPs are the main contributor to the observed high flow characteristics. Their number and size distribution are found to be more important than the depth distribution. Our model results are corroborated by geochemical and geophysical observations.

  6. Rapid assessment of Wreathed Hornbill Aceros undulates (Aves: Bucerotidae populations and conservation issues in fragmented lowland tropical forests of Arunachal Pradesh, India

    Directory of Open Access Journals (Sweden)

    C.M. Krishna

    2012-11-01

    Full Text Available A rapid assessment of Wreathed Hornbills, their distribution and abundance was carried out in fragmented lowland tropical forests of Lower Dibang Valley District, Arunachal Pradesh, northeastern India from October 2010 to April 2011 using the total count method. A total of 62km distance was covered on foot to survey four study sites: Horupahar, Delo, Koronu and Injunu. Nine flocks of 172 hornbills were sighted. Aceros undulatus flock size ranged from 8-38 individuals with a mean of about 19.1 plus or minus 2.6. Illegal logging, hunting for bushmeat and other body parts (feathers, beak etc. for decorating the head gear and house interiors by the local tribals were observed as the major threats to the species in the study areas.

  7. A Late Holocene Record of Human Impact in the Tropical Lowlands of the Mexican Gulf Coast: Lago Verde.

    Science.gov (United States)

    Socorro, L.; Sosa, S.; Caballero, M.; Rodriguez, A.; Ortega, B.

    2005-05-01

    Lago Verde is a maar lake (18 36 43 N; 95 20 52 W) located on the Gulf Coast of Mexico in "Los Tuxtlas" region. The area was cover by tropical rain forest and is part of the core area of the earliest Mesoamerican cultures. A 6 m sediment core was obtained in order to document vegetation and lake level history of this area. Lago Verde is a shallow, eutrophic lake (max. 4 m), the natural vegetation has been removed and grasslands with some tropical trees such Bursera grows around the lake. According with the radiocarbon chronology the sequence covers the last 2500 yr BP. At the base of the sequence low abundance of tropical trees is record, with intermediate lake levels. A sudden change in the pollen stratigraphy occurs at ca. 2000 yr BP, with important presence of Poaceae, Ambrosia and Cheno.-Am. along with Zea mays indicating human activity in the area. This is associated with a change in limnological conditions, recording turbid, shallow environments. This pollen signals correlates with dry phases in Yucatan, suggesting that this dry climatic signal probably had effect on an ample area of Mexico. However, at 1200 yr BP, no more Zea mays pollen is recovered suggesting the abandonment of the area. Lake levels recover as well as the tropical forest. The last 150 yr BP is characterized by the reduction in the pollen of tropical forest trees, presence of Zea mays, increased erosion rates, turbidity and eutrophication in the lake, all related to deforestation.

  8. Tree Species Diversity, Richness, and Similarity in Intact and Degraded Forest in the Tropical Rainforest of the Congo Basin: Case of the Forest of Likouala in the Republic of Congo

    Directory of Open Access Journals (Sweden)

    Suspense Averti Ifo

    2016-01-01

    Full Text Available Trees species diversity, richness, and similarity were studied in fifteen plots of the tropical rainforests in the northeast of the Republic of Congo, based on trees inventories conducted on fifteen 0.25 ha plots installed along different types of forests developed on terra firma, seasonally flooded, and on flooded terra. In all of the plots installed, all trees with diameter at breast height, DBH ≥ 5 cm, were measured. The Shannon diversity index, species richness, equitability, and species dominance were computed to see the variation in tree community among plots but also between primary forest and secondary forest. A total of 1611 trees representing 114 species and 35 families were recorded from a total area of 3.75 ha. Euphorbiaceae was the dominant family in the forest with 12 species, followed by Fabaceae-Mimosoideae (10 species and Phyllanthaceae (6 species and Guttiferae (6 species. The biodiversity did not vary greatly from plot to plot on the whole of the study area (3.75 ha. The low value of Shannon index was obtained in plot 11 (H′=0.75 whereas the highest value was obtained in plot 12 (H′=4.46. The values of this index vary from 0.23 to 0.95 in plots P11 and P15, respectively. Results obtained revealed high biodiversity of trees of the forest of Impfondo-Dongou. The information on tree species structure and function can provide baseline information for conservation of the biodiversity of the tropical forest in this area.

  9. Soilborne fungi have host affinity and host-specific effects on seed germination and survival in a lowland tropical forest

    Science.gov (United States)

    The Janzen-Connell (JC) hypothesis provides a powerful framework for explaining the maintenance of tree diversity in tropical forests. Its central tenet -- that recruits experience high mortality near conspecifics and at high densities -- assumes a degree of host specialization in interactions betwe...

  10. Bird community changes in response to single and repeated fires in a lowland tropical rainforest of eastern Borneo

    NARCIS (Netherlands)

    Slik, J.W.F.; Balen, van S.

    2006-01-01

    Our current understanding of bird community responses to tropical forest fires is limited and strongly geographically biased towards South America. Here we used the circular plot method to carry out complete bird inventories in undisturbed, once burned (1998) and twice burned forests (1983 and 1998)

  11. Soil Type Has a Stronger Role than Dipterocarp Host Species in Shaping the Ectomycorrhizal Fungal Community in a Bornean Lowland Tropical Rain Forest

    Directory of Open Access Journals (Sweden)

    Adam L. Essene

    2017-10-01

    Full Text Available The role that mycorrhizal fungal associations play in the assembly of long-lived tree communities is poorly understood, especially in tropical forests, which have the highest tree diversity of any ecosystem. The lowland tropical rain forests of Southeast Asia are characterized by high levels of species richness within the family Dipterocarpaceae, the entirety of which has been shown to form obligate ectomycorrhizal (ECM fungal associations. Differences in ECM assembly between co-occurring species of dipterocarp have been suggested, but never tested in adult trees, as a mechanism for maintaining the coexistence of closely related tree species in this family. Testing this hypothesis has proven difficult because the assembly of both dipterocarps and their ECM associates co-varies with the same edaphic variables. In this study, we used high-throughput DNA sequencing of soils and Sanger sequencing of root tips to evaluate how ECM fungi were structured within and across a clay–sand soil nutrient ecotone in a mixed-dipterocarp rain forest in Malaysian Borneo. We compared assembly patterns of ECM fungi in bulk soil to ECM root tips collected from three ecologically distinct species of dipterocarp. This design allowed us to test whether ECM fungi are more strongly structured by soil type or host specificity. As with previous studies of ECM fungi on this plot, we observed that clay vs. sand soil type strongly structured both the bulk soil and root tip ECM fungal communities. However, we also observed significantly different ECM communities associated with two of the three dipterocarp species evaluated on this plot. These results suggest that ECM fungal assembly on these species is shaped by a combination of biotic and abiotic factors, and that the soil edaphic niche occupied by different dipterocarp species may be mediated by distinct ECM fungal assemblages.

  12. Conversion of tropical lowland forest reduces nutrient return through litterfall, and alters nutrient use efficiency and seasonality of net primary production.

    Science.gov (United States)

    Kotowska, Martyna M; Leuschner, Christoph; Triadiati, Triadiati; Hertel, Dietrich

    2016-02-01

    Tropical landscapes are not only rapidly transformed by ongoing land-use change, but are additionally confronted by increasing seasonal climate variation. There is an increasing demand for studies analyzing the effects and feedbacks on ecosystem functioning of large-scale conversions of tropical natural forest into intensively managed cash crop agriculture. We analyzed the seasonality of aboveground litterfall, fine root litter production, and aboveground woody biomass production (ANPP(woody)) in natural lowland forests, rubber agroforests under natural tree cover ("jungle rubber"), rubber and oil palm monocultures along a forest-to-agriculture transformation gradient in Sumatra. We hypothesized that the temporal fluctuation of litter production increases with increasing land-use intensity, while the associated nutrient fluxes and nutrient use efficiency (NUE) decrease. Indeed, the seasonal variation of aboveground litter production and ANPP(woody) increased from the natural forest to the plantations, while aboveground litterfall generally decreased. Nutrient return through aboveground litter was mostly highest in the natural forest; however, it was significantly lower only in rubber plantations. NUE of N, P and K was lowest in the oil palm plantations, with natural forest and the rubber systems showing comparably high values. Root litter production was generally lower than leaf litter production in all systems, while the root-to-leaf ratio of litter C flux increased along the land-use intensity gradient. Our results suggest that nutrient and C cycles are more directly affected by climate seasonality in species-poor agricultural systems than in species-rich forests, and therefore might be more susceptible to inter-annual climate fluctuation and climate change.

  13. Gibbons (Nomascus gabriellae) provide key seed dispersal for the Pacific walnut (Dracontomelon dao), in Asia's lowland tropical forest

    Science.gov (United States)

    Hai, Bach Thanh; Chen, Jin; McConkey, Kim R.; Dayananda, Salindra K.

    2018-04-01

    Understanding the mutualisms between frugivores and plants is essential for developing successful forest management and conservation strategies, especially in tropical rainforests where the majority of plants are dispersed by animals. Gibbons are among the most effective seed dispersers in South East Asia's tropical forests, but are also one of the highly threatened arboreal mammals in the region. Here we studied the seed dispersal of the Pacific walnut (Dracontomelon dao), a canopy tree which produces fruit that are common in the diet of the endangered southern yellow-cheeked crested gibbon (Nomascus gabriellae). We found that gibbons were the most effective disperser for this species; they consumed approximately 45% of the fruit crop, which was four times more than that consumed by macaques - the only other legitimate disperser. Gibbons tracked the temporal (but not spatial) abundance of ripe fruits, indicating this fruit was a preferred species for the gibbon. Both gibbons and macaques dispersed the majority (>90%) of the seeds at least 20 m away from parent crowns, with mean dispersal distances by gibbons measuring 179.3 ± 98.0 m (range: 4-425 m). Seeds defecated by gibbons germinated quicker and at greater rates than seeds spat by macaques, or in undispersed fruits. Gibbon-dispersed seeds were also more likely to be removed by unknown seed predators or unknown secondary dispersers. Overall, gibbons play a key role in the regeneration of the Pacific walnut. Our findings have significant implications both for the management of the Pacific walnut tree dominating tropical rainforest as well as the reintroduction program of the Southern yellow-cheeked crested gibbon.

  14. In tropical lowland rain forests monocots have tougher leaves than dicots, and include a new kind of tough leaf

    DEFF Research Database (Denmark)

    Dominy, N.J.; Grubb, P.J.; Jackson, R.V.

    2008-01-01

    -tolerant or gap-demanding species were considered. Conclusions: It is predicted that monocots will be found to experience lower rates of herbivory by invertebrates than dicots. The tough monocot leaves include both stiff leaves containing relatively little water at saturation (e.g. palms), and leaves which lack...... stiffness, are rich in water at saturation and roll readily during dry weather or even in bright sun around midday (e.g. gingers, heliconias and marants). Monocot leaves also show that it is possible for leaves to be notably tough throughout the expansion phase of development, something never recorded...... for dicots. The need to broaden the botanist's mental picture of a ‘tough leaf' is emphasized.   Key words: Dicots, fracture toughness, herbivory, leaves, monocots, punch strength, tropical rain forest  ...

  15. Shaping forest safety nets with markets: Adaptation to climate change under changing roles of tropical forests in Congo Basin

    NARCIS (Netherlands)

    Nkem, J.; Kalame, F.B.; Idinoba, M.; Somorin, O.A.; Ndoye, O.; Awono, A.

    2010-01-01

    Tropical forests hold several goods and services used by forest-dependent people as safety nets to traverse difficult periods of resource supply. These same goods and services are constantly surrounded by emerging markets linking remote communities with major urban centers nationally and

  16. Seed dispersal and movement patterns in two species of Ceratogymna hornbills in a West African tropical lowland forest.

    Science.gov (United States)

    Holbrook, Kimberly M; Smith, Thomas B

    2000-10-01

    We studied two species of Ceratogymna hornbills, the black-casqued hornbill, C. atrata, and the white-thighed hornbill, C. cylindricus, in the tropical forests of Cameroon, to understand their movement patterns and evaluate their effectiveness as seed dispersers. To estimate hornbill contribution to a particular tree species' seed shadow we combined data from movements, determined by radio-tracking, with data from seed passage trials. For 13 individuals tracked over 12 months, home range varied between 925 and 4,472 ha, a much larger area than reported for other African avian frugivores. Seed passage times ranged from 51 to 765 min, with C. atrata showing longer passage times than C. cylindricus, and larger seeds having longer gut retention times than smaller seeds. Combining these data, we estimated that seed shadows were extensive for the eight tree species examined, with approximately 80% of seeds moved more than 500 m from the parent plant. Maximum estimated dispersal distances for larger seeds were 6,919 and 3,558 m for C. atrata and C. cylindricus, respectively. The extent of hornbill seed shadows suggests that their influence in determining forest structure will likely increase as other larger mammalian dispersers are exterminated.

  17. Feeding behavior and activity budget of the southern yellow-cheeked crested gibbons (Nomascus gabriellae) in a lowland tropical forest.

    Science.gov (United States)

    Bach, Thanh H; Chen, Jin; Hoang, Minh D; Beng, Kingsly C; Nguyen, Van T

    2017-08-01

    The southern yellow-cheeked crested gibbon (Nomascus gabriellae), an endangered species native to Vietnam and Cambodia, lives exclusively in undisturbed tropical forests and depends primarily on ripe fruit for food. Although this species is highly threatened, its ecology and conservation status remain relatively unknown. In order to understand how this heavily frugivorous primate adapts to the seasonal fluctuation of fruit resources in the forest, we collected feeding behavior and ranging activity data on one group of southern yellow-cheeked crested gibbons in Cat Tien National Park, Vietnam, over 1-year period. We compared these data to information on phenological patterns at the site gleaned during a prior study. We found that the gibbons gathered most of their food from 69 different plant species and also consumed insects and bird eggs. Fruits were the main dietary item (43.3%), followed by leaves (38.4%), flowers (11.6%), and other plant parts (6.0%). A significant seasonal shift in diet was observed; fruit generally dominated the diet in the rainy season and leaves in the dry season. The gibbons often started daily activities very early (05:10 am) in the morning and also ended quite early (16:45 pm) in the afternoon. Socializing was concentrated in the early morning, feeding had a bimodal pattern of high activity levels in mid-morning and mid-afternoon, and resting was most intense at the earliest and latest hours of the day and at midday, with proportionally less time used for traveling at these times. Averaged over the annual cycle, the gibbons spent 45% of their time feeding, 31.9% resting, 14.1% traveling, and 9.0% socializing. The percentage of time allocated to different activities varied significantly across months and between the dry and rainy seasons. Monthly variation in the activity budget was strongly related to changes in diet. In the rainy season, when the gibbons ate a higher percentage of fruit, they decreased their feeding time, while

  18. Accumulation of toxic metals and organic micro-pollutants in sediments from tropical urban rivers, Kinshasa, Democratic Republic of the Congo.

    Science.gov (United States)

    Kilunga, Pitchouna I; Sivalingam, Periyasamy; Laffite, Amandine; Grandjean, Dominique; Mulaji, Crispin K; de Alencastro, Luiz Felippe; Mpiana, Pius T; Poté, John

    2017-07-01

    The increasing contamination of fresh water resource by toxic metals and Persistence Organic Pollutants (POPs) is a major environmental concern globally. In the present investigation, surface sediments collected from three main rivers named, Makelele, Kalamu and Nsanga, draining through the city of Kinshasa, Democratic Republic of the Congo, were characterized for grain size, organic matter, toxic metals, POPs (including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs)), and polycyclic aromatic hydrocarbons (PAHs). Furthermore, enrichment factor (EF) and geoaccumulation index (Igeo) were performed to determine metal source and pollution status. The results highlighted high concentration of toxic metals in all sediment samples, reaching the values (mg kg -1 ) of 325 (Cu), 549 (Zn), 165 (Pb) and 1.5 (Cd). High values of PCBs and OCPs were detected in sediment samples, e.g. in Makelele river, PCB values ranged from 0.9 to 10.9 with total PCBs (∑7 PCBs × 4.3): 169.3 μg kg -1 ; OCPs from 21.6 to 146.8 with ∑OCPs: 270.6 μg kg -1 . The PBDEs concentrations were higher in investigated rivers comparatively with values detected in many rivers from Sub-Saharan Africa. The ΣPAHs value ranged from 22.6 to 1011.9 μg kg -1 . River contamination may be explained by local intense domestic activities, urban and agricultural runoff, industrial and hospital wastewaters discharge into the rivers without prior treatment. This research provides not only a first baseline information on the extent of contamination in this tropical ecosystem but also represents useful tools incorporated to evaluate sediment quality in the river receiving systems which can be applied to similar aquatic environments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Assessment of pathogenic bacteria in water and sediment from a water reservoir under tropical conditions (Lake Ma Vallée), Kinshasa Democratic Republic of Congo.

    Science.gov (United States)

    Mwanamoki, Paola M; Devarajan, Naresh; Thevenon, Florian; Atibu, Emmanuel K; Tshibanda, Joseph B; Ngelinkoto, Patience; Mpiana, Pius T; Prabakar, Kandasamy; Mubedi, Josué I; Kabele, Christophe G; Wildi, Walter; Poté, John

    2014-10-01

    This study was conducted to assess potential human health risks presented by pathogenic bacteria in a protected multi-use lake-reservoir (Lake Ma Vallée) located in west of Kinshasa, Democratic Republic of Congo (DRC). Water and surface sediments from several points of the Lake were collected during summer. Microbial analysis was performed for Escherichia coli, Enterococcus (ENT), Pseudomonas species and heterotrophic plate counts. PCR amplification was performed for the confirmation of E. coli, ENT, Pseudomonas spp. and Pseudomonas aeruginosa isolated from samples. The results reveal low concentration of bacteria in water column of the lake, the bacterial quantification results observed in this study for the water column were below the recommended limits, according to WHO and the European Directive 2006/7/CE, for bathing water. However, high concentration of bacteria was observed in the sediment samples; the values of 2.65 × 10(3), 6.35 × 10(3), 3.27 × 10(3) and 3.60 × 10(8) CFU g(-1) of dry sediment for E. coli, ENT, Pseudomonas spp. and heterotrophic plate counts, respectively. The results of this study indicate that sediments of the Lake Ma Vallée can constitute a reservoir of pathogenic microorganisms which can persist in the lake. Possible resuspension of faecal indicator bacteria and pathogens would affect water quality and may increase health risks to the population during recreational activities. Our results indicate that the microbial sediment analysis provides complementary and important information for assessing sanitary quality of surface water under tropical conditions.

  20. The nitrogen budget for different forest types in the central Congo Basin

    Science.gov (United States)

    Bauters, Marijn; Verbeeck, Hans; Cizungu, Landry; Boeckx, Pascal

    2016-04-01

    Characterization of fundamental processes in different forest types is vital to understand the interaction of forests with their changing environment. Recent data analyses, as well as modeling activities have shown that the CO2 uptake by terrestrial ecosystems strongly depends on site fertility, i.e. nutrient availability. Accurate projections of future net forest growth and terrestrial CO2 uptake thus necessitate an improved understanding on nutrient cycles and how these are coupled to the carbon (C) cycle in forests. This holds especially for tropical forests, since they represent about 40-50% of the total carbon that is stored in terrestrial vegetation, with the Amazon basin and the Congo basin being the largest two contiguous blocks. However, due to political instability and reduced accessibility in the central Africa region, there is a strong bias in scientific research towards the Amazon basin. Consequently, central African forests are poorly characterized and their role in global change interactions shows distinct knowledge gaps, which is important bottleneck for all efforts to further optimize Earth system models explicitly including this region. Research in the Congo Basin region should combine assessments of both carbon stocks and the underlying nutrient cycles which directly impact the forest productivity. We set up a monitoring network for carbon stocks and nitrogen fluxes in four different forest types in the Congo Basin, which is now operative. With the preliminary data, we can get a glimpse of the differences in nitrogen budget and biogeochemistry of African mixed lowland rainforest, monodominant lowland forest, mixed montane forest and eucalypt plantations.

  1. Monitoring Forest Carbon Stocks and Fluxes in the Congo Basin

    OpenAIRE

    2010-01-01

    The Central African Forests Commission (COMIFAC) and its partners (OFAC, USAID, EC-JRC, OSFAC, WWF, WRI, WCS, GOFC-GOLD, START, UN-FAO) organized an international conference on "Monitoring of Carbon stocks and fluxes in the Congo Basin" in Brazzaville, Republic of Congo, 2-4 February 2010. The conference brought together leading international specialists to discuss approaches for quantifying stocks and flows of carbon in tropical forests of the Congo Basin. The conference provided a unique op...

  2. Drivers of aboveground wood production in a lowland tropical forest of West Africa: teasing apart the roles of tree density, tree diversity, soil phosphorus, and historical logging.

    Science.gov (United States)

    Jucker, Tommaso; Sanchez, Aida Cuni; Lindsell, Jeremy A; Allen, Harriet D; Amable, Gabriel S; Coomes, David A

    2016-06-01

    Tropical forests currently play a key role in regulating the terrestrial carbon cycle and abating climate change by storing carbon in wood. However, there remains considerable uncertainty as to whether tropical forests will continue to act as carbon sinks in the face of increased pressure from expanding human activities. Consequently, understanding what drives productivity in tropical forests is critical. We used permanent forest plot data from the Gola Rainforest National Park (Sierra Leone) - one of the largest tracts of intact tropical moist forest in West Africa - to explore how (1) stand basal area and tree diversity, (2) past disturbance associated with past logging, and (3) underlying soil nutrient gradients interact to determine rates of aboveground wood production (AWP). We started by statistically modeling the diameter growth of individual trees and used these models to estimate AWP for 142 permanent forest plots. We then used structural equation modeling to explore the direct and indirect pathways which shape rates of AWP. Across the plot network, stand basal area emerged as the strongest determinant of AWP, with densely packed stands exhibiting the fastest rates of AWP. In addition to stand packing density, both tree diversity and soil phosphorus content were also positively related to productivity. By contrast, historical logging activities negatively impacted AWP through the removal of large trees, which contributed disproportionately to productivity. Understanding what determines variation in wood production across tropical forest landscapes requires accounting for multiple interacting drivers - with stand structure, tree diversity, and soil nutrients all playing a key role. Importantly, our results also indicate that logging activities can have a long-lasting impact on a forest's ability to sequester and store carbon, emphasizing the importance of safeguarding old-growth tropical forests.

  3. Effects of untreated hospital effluents on the accumulation of toxic metals in sediments of receiving system under tropical conditions: case of South India and Democratic Republic of Congo.

    Science.gov (United States)

    Mubedi, Josué Ilunga; Devarajan, Naresh; Le Faucheur, Séverine; Mputu, John Kayembe; Atibu, Emmanuel K; Sivalingam, Periyasamy; Prabakar, Kandasamy; Mpiana, Pius T; Wildi, Walter; Poté, John

    2013-10-01

    Physicochemical and ecotoxicological analyses have been performed to assess the quality of sediments receiving untreated hospital effluents from Indian and Democratic Republic of Congo (DRC) hospitals. The sediments were collected monthly and characterized for grain size, organic matter, total organic carbon, total carbon, nitrogen, phosphorus, toxic metals and ecotoxicity. The results highlight the high concentration of toxic metals from the Indian hospital effluent receiving systems, especially for Cr, Cu, As, Zn and Hg. On the other hand, the metal concentrations in the sediment receiving system from DRC are low (e.g. maximum Hg and Zn concentration were 0.46 and 48.84 mg kg(-1) respectively). Ostracods exposed to sediment samples H2 (September month sample) and H3 (June and September month samples) were found dead after 6d of exposure whereas the higher mortality rate for Congo sediments was 23% but was accompanied with 33 ± 7% of growth inhibition. The results of this study show the variation of sediment composition on toxic metal levels as well as toxicity related to both, the type of hospitals and the sampling period. Additionally, hospital effluent disposal practices at the study sites can lead to the pollution of water resources and may generate risks for aquatic organisms and human health. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Impacts of logging and hunting on western lowland gorilla (Gorilla gorilla gorilla populations and consequences for forest regeneration. A review

    Directory of Open Access Journals (Sweden)

    Haurez, B.

    2013-01-01

    Full Text Available Timber exploitation is rapidly expanding throughout the Congo Basin. Forest areas assigned to timber harvesting have sharply expanded over the decades and logging concessions now largely overlap with the range of western lowland gorilla (Gorilla gorilla gorilla Savage & Wyman, 1847. However this species, which is considered as critically endangered by IUCN, could play an essential role in maintaining the structure and composition of tropical rainforest notably through seed dispersal services. This is likely due to its frugivorous diet, high stomach capacity and ability to swallow seeds of variable sizes. Moreover gorillas have a long gut retention time of ingested food, travel long daily distances and deposit most ingested seeds in suitable habitats for plant development (such as logging gaps. Consequently, the preservation of the role of gorilla in forest regeneration is essential in the context of logged forest ecosystems. Timber harvesting has two major opposing impacts on gorilla populations: on the one hand, gorillas benefit from growth of herbaceous vegetation (e.g. Marantaceae and Zingiberaceae following forest canopy opening, as such herbs provide both staple food and nest-building materials; on the other hand, gorilla populations suffer with the rise in hunting associated with logging activity, especially with road network installation. Considering the potential negative knock-on effects of logging concessions on the ecological function of western lowland gorilla, the implementation of timber harvesting methods that preserve gorilla populations is a considerable challenge for forest sustainability, as well as for gorilla's conservation.

  5. Sorbitol-fermenting Bifidobacteria are indicators of very recent human faecal pollution in streams and groundwater habitats in urban tropical lowlands

    Science.gov (United States)

    2010-01-01

    Sorbitol-fermenting Bifidobacteria (SFB) proved to be an excellent indicator of very recent human faecal pollution (hours to days) in the investigated tropical stream and groundwater habitats. SFB were recovered from human faeces and sources potentially contaminated with human excreta. SFB were undetectable in animal faeces and environmental samples not contaminated with human faeces. Microcosm studies demonstrated a rapid die-off rate in groundwater (T90 value 0.6 days) and stream water (T90 value 0.9–1.7 days). Discrimination sensitivity analysis, including E. coli, faecal coliforms, total coliforms and Clostridium perfringens spores, revealed high ability of SFB to distinguish differing levels of faecal pollution especially for streams although high background levels of interfering bacteria can complicate its recovery on the used medium. Due to its faster die-off, as compared to many waterborne pathogens, SFB cannot replace microbiological standard parameters for routine water quality monitoring but it is highly recommendable as a specific and complementary tool when human faecal pollution has to be localized or verified. Because of its exclusive faecal origin and human specificity it seems also worthwhile to include SFB in future risk evaluation studies at tropical water resources in order to evaluate under which situations risks of infection may be indicated. PMID:20375476

  6. Effects of the genotype and environment interaction on sugar accumulation in sweet sorghum varieties (Sorghum bicolor -{L.}- Moench grown in the lowland tropics of Colombia

    Directory of Open Access Journals (Sweden)

    Jaime Humberto Bernal

    2014-12-01

    Full Text Available Sugar production in sweet sorghums is affected by the environment. Therefore, in this study on the effects of the genotype x environment interaction on sugar accumulation, plant traits associated with the sugar content in the stem were evaluated in ten sorghum genotypes grown in six contrasting environments. The results indicated that the stem dry weight, juice sugar concentration (°Brix, stem sugar content and juice volume were controlled by the genetic constitution of the genotype, with a large environmental contribution to their expression. The results allowed for the identification of the sweet sorghum genotypes that have a high potential for the biofuel agroindustry due to their high sugar contents in the environmental conditions of Palmira, Espinal, Cerete and Codazzi. Humid tropical environments such as Gaitan and Villavicencio were less favorable for the competitive production of sweet sorghums for bioethanol due to their low levels of solar radiation and soil fertility.

  7. Conversion of lowland tropical forests to tree cash crop plantations loses up to one-half of stored soil organic carbon.

    Science.gov (United States)

    van Straaten, Oliver; Corre, Marife D; Wolf, Katrin; Tchienkoua, Martin; Cuellar, Eloy; Matthews, Robin B; Veldkamp, Edzo

    2015-08-11

    Tropical deforestation for the establishment of tree cash crop plantations causes significant alterations to soil organic carbon (SOC) dynamics. Despite this recognition, the current Intergovernmental Panel on Climate Change (IPCC) tier 1 method has a SOC change factor of 1 (no SOC loss) for conversion of forests to perennial tree crops, because of scarcity of SOC data. In this pantropic study, conducted in active deforestation regions of Indonesia, Cameroon, and Peru, we quantified the impact of forest conversion to oil palm (Elaeis guineensis), rubber (Hevea brasiliensis), and cacao (Theobroma cacao) agroforestry plantations on SOC stocks within 3-m depth in deeply weathered mineral soils. We also investigated the underlying biophysical controls regulating SOC stock changes. Using a space-for-time substitution approach, we compared SOC stocks from paired forests (n = 32) and adjacent plantations (n = 54). Our study showed that deforestation for tree plantations decreased SOC stocks by up to 50%. The key variable that predicted SOC changes across plantations was the amount of SOC present in the forest before conversion--the higher the initial SOC, the higher the loss. Decreases in SOC stocks were most pronounced in the topsoil, although older plantations showed considerable SOC losses below 1-m depth. Our results suggest that (i) the IPCC tier 1 method should be revised from its current SOC change factor of 1 to 0.6 ± 0.1 for oil palm and cacao agroforestry plantations and 0.8 ± 0.3 for rubber plantations in the humid tropics; and (ii) land use management policies should protect natural forests on carbon-rich mineral soils to minimize SOC losses.

  8. Conversion of lowland tropical forests to tree cash crop plantations loses up to one-half of stored soil organic carbon

    Science.gov (United States)

    van Straaten, Oliver; Corre, Marife D.; Wolf, Katrin; Tchienkoua, Martin; Cuellar, Eloy; Matthews, Robin B.; Veldkamp, Edzo

    2015-01-01

    Tropical deforestation for the establishment of tree cash crop plantations causes significant alterations to soil organic carbon (SOC) dynamics. Despite this recognition, the current Intergovernmental Panel on Climate Change (IPCC) tier 1 method has a SOC change factor of 1 (no SOC loss) for conversion of forests to perennial tree crops, because of scarcity of SOC data. In this pantropic study, conducted in active deforestation regions of Indonesia, Cameroon, and Peru, we quantified the impact of forest conversion to oil palm (Elaeis guineensis), rubber (Hevea brasiliensis), and cacao (Theobroma cacao) agroforestry plantations on SOC stocks within 3-m depth in deeply weathered mineral soils. We also investigated the underlying biophysical controls regulating SOC stock changes. Using a space-for-time substitution approach, we compared SOC stocks from paired forests (n = 32) and adjacent plantations (n = 54). Our study showed that deforestation for tree plantations decreased SOC stocks by up to 50%. The key variable that predicted SOC changes across plantations was the amount of SOC present in the forest before conversion—the higher the initial SOC, the higher the loss. Decreases in SOC stocks were most pronounced in the topsoil, although older plantations showed considerable SOC losses below 1-m depth. Our results suggest that (i) the IPCC tier 1 method should be revised from its current SOC change factor of 1 to 0.6 ± 0.1 for oil palm and cacao agroforestry plantations and 0.8 ± 0.3 for rubber plantations in the humid tropics; and (ii) land use management policies should protect natural forests on carbon-rich mineral soils to minimize SOC losses. PMID:26217000

  9. Apport des arbres fruitiers à la sécurité alimentaire en milieu urbain tropical: cas de la commune de Limete- Kinshasa, République Démocratique du Congo

    Directory of Open Access Journals (Sweden)

    Luyindula, N.

    2005-01-01

    Full Text Available Fruit Trees Contribution to Food Security in Tropical Urban Environment: Instance of Commune of Limete in Kinshasa- Democratic Republic of Congo. Problems of hunger and malnutrition in urban environnements force the populations to exploit all the food resources available. This work investigates the contribution to the diet of the population of the edible fruits produced by the 19 species of trees found in a district of Kinshasa. An investigation carried out in 1.09% of the 18,475 household plots of the commune of Limete permitted to estimate at approximately 47,000 feet the number of trees planted there and their annual production at approximately 4.087 tons. The six main species (Mangifera indica, Persea americana, Elaeis guineensis, Carica papaya, Dacryodes edulis and Musa paradisiaca account on their own for an approximate total of 36,400 feet. The contribution of these species to the population alimentation was estimated respectively at 10.9 g, 6.1 g, 4.5 g, 4.4 g, 1.8 g and 0.6 g of fruits per person and per day. The control of certain environmental- friendly techniques and environmental education relating to the trees in urban environment should increase the importance of this contribution.

  10. Changes in Arbuscular Mycorrhizal Fungal Abundance and Community Structure in Response to the Long-Term Manipulation of Inorganic Nutrients in a Lowland Tropical Forest

    Science.gov (United States)

    Sheldrake, Merlin; Rosenstock, Nicholas; Tanner, Ed

    2014-05-01

    The arbuscular mycorrhizal (AM) symbiosis is considered primarily mutualistic. In exchange for up to 30% of plants' total photosynthate, AM provide improved access to mineral nutrients. While there is evidence that AM fungi provide nitrogen, potassium and other nutrients to their host plants, most research has focused on their effect on plant phosphorus uptake. Pot experiments have shown, and field experiments have provided further support, that nutrient availability (primarily P, but also N) is inversely correlated with mycorrhizal colonization, indicating plant control over carbon losses to AM fungi. Yet pot experiments have also shown that some fungal species are more mutualistic than others and that AM colonization may cause decreased plant growth, suggesting that plant control is not absolute. AMF communities are diverse, and it is poorly understood how factors such as adaptation to local soil environment, fungal-plant compatibility, and plant nutrient status combine to shape AMF community structure. We conducted a study to examine the relative effects of N, P, and K addition on the AMF community in a plant species rich tropical forest, given the long-held belief that AMF are primarily involved in plant P uptake, particularly on weathered tropical soils. Our study site is the Barro Colorado Nature Monument in Panama. It is a 13 year-old factorial N, P, and K addition experiment (40 m x 40m plots; n=4) in an AMF dominated, old (>200 yr), secondary, tropical forest. Previous research has shown co-limitation by N, P, and K, but the strongest plant growth responses were obtained with K additions. We analyzed the AMF community using 454 pyrosequencing of the ribosomal small subunit (SSU) on both soils and the roots of the 6 dominant AMF tree species. Additionally, we used the AMF-specific neutral lipid fatty acid (NLFA) biomarker as a measure of AMF biomass. Both AMF biomass and community structure were altered by nutrient additions. AMF biomass in soil was reduced

  11. Functional diversity of photosynthetic light use of sixteen vascular epiphyte species under fluctuating irradiance in the canopy of a giant Virola michelii (Myristicaceae tree in the tropical lowland forest of French Guyana

    Directory of Open Access Journals (Sweden)

    Uwe eRascher

    2012-01-01

    Full Text Available Here we present the first study, in which a large number of different vascular epiphyte species were measured for their photosynthetic performance in the natural environment of their phorophyte in the lowland rainforest of French Guyana. More than 70 epiphyte species covered the host tree in a dense cover. Of these, the photosynthesis of 16 abundant species was analyzed intensely over several months. Moreover, the light environment was characterized with newly developed light sensors that recorded continuously and with high temporal resolution light intensity next to the epiphytes. Light intensity was highly fluctuating and showed great site specific spatio-temporal variations of photosynthetic photon flux. Using a novel computer routine we quantified the integrated light intensity the epiphytes were exposed to in a 3-hour window and we related this light intensity to measurements of the actual photosynthetic status. It could be shown that the photosynthetic apparatus of the epiphytes was well adapted to the quickly changing light conditions. Some of the epiphytes were chronically photoinhibited at pre-dawn and significant acute photoinhibition, expressed by a reduction of potential quantum efficiency (Fv/Fm30’, was observed during the day. By correlating (Fv/Fm30’ to the integrated and weighted light intensity perceived during the previous 3 hours, it became clear that acute photoinhibition was related to light environment prior to the measurements. Additionally photosynthetic performance was not determined by rain events, with the exception of an Aechmea species. This holds true for all the other 15 species of this study and we thus conclude that actual photosynthesis of these tropical epiphytes was determined by the specific and fluctuating light conditions of their microhabitat and cannot be simply attributed to light adapted ancestors.

  12. Spatial scale and sampling resolution affect measures of gap disturbance in a lowland tropical forest: implications for understanding forest regeneration and carbon storage

    Science.gov (United States)

    Lobo, Elena; Dalling, James W.

    2014-01-01

    Treefall gaps play an important role in tropical forest dynamics and in determining above-ground biomass (AGB). However, our understanding of gap disturbance regimes is largely based either on surveys of forest plots that are small relative to spatial variation in gap disturbance, or on satellite imagery, which cannot accurately detect small gaps. We used high-resolution light detection and ranging data from a 1500 ha forest in Panama to: (i) determine how gap disturbance parameters are influenced by study area size, and the criteria used to define gaps; and (ii) to evaluate how accurately previous ground-based canopy height sampling can determine the size and location of gaps. We found that plot-scale disturbance parameters frequently differed significantly from those measured at the landscape-level, and that canopy height thresholds used to define gaps strongly influenced the gap-size distribution, an important metric influencing AGB. Furthermore, simulated ground surveys of canopy height frequently misrepresented the true location of gaps, which may affect conclusions about how relatively small canopy gaps affect successional processes and contribute to the maintenance of diversity. Across site comparisons need to consider how gap definition, scale and spatial resolution affect characterizations of gap disturbance, and its inferred importance for carbon storage and community composition. PMID:24452032

  13. How can we conserve intact tropical peatlands?

    Science.gov (United States)

    Lawson, Ian; Roucoux, Katherine

    2017-04-01

    The scientific community has, for more than three decades, been expressing increasing alarm about the fate of peatlands in parts of Indonesia and Malaysia, where extensive land-use conversion and drainage for rice and oil palm have greatly compromised peatland hydrology, ecology, biological richness, and carbon storage. The discourse in the literature on these peatlands is now moving on from attempts to preserve the last remaining fragments of peat-swamp forest, towards discussion of how best to restore damaged ecosystems, and whether it is possible to manage plantations more 'sustainably'. It is becoming increasingly clear, however, that peatlands occur quite widely in other parts of the lowland tropics, including parts of Amazonia and the Congo Basin, and many of these peatlands can reasonably be described as 'intact': although few if any parts of the tropics are totally unaffected by human actions, the hydrology and functional ecology of these systems appear to be close to a 'natural' state. The question then arises as to what should be done with the knowledge of their existence. Here we analyse the arguments in favour of protecting intact peatlands, and the potential conflicts with other priorities such as economic development and social justice. We evaluate alternative mechanisms for protecting intact peatlands, focusing on the particular issues raised by peatlands as opposed to other kinds of tropical ecosystem. We identify ways in which natural science agendas can help to inform these arguments, using our own contributions in palaeoecology and carbon mapping as examples. Finally, we argue for a radical reconsideration of research agendas in tropical peatlands, highlighting the potential contribution of methodologies borrowed from the social sciences and humanities.

  14. Hyperspectral remote sensing of canopy biodiversity in Hawaiian lowland rainforests

    Science.gov (United States)

    Kimberly M. Carlson; Gregory P. Asner; R. Flint Hughes; Rebecca Ostertag; Roberta E. Martin

    2007-01-01

    Mapping biological diversity is a high priority for conservation research, management and policy development, but few studies have provided diversity data at high spatial resolution from remote sensing. We used airborne imaging spectroscopy to map woody vascular plant species richness in lowland tropical forest ecosystems in Hawaii. Hyperspectral signatures spanning...

  15. Eficiência no uso de nitrogênio em genótipos de arroz em solos de várzea tropical do Estado do Tocantins = Nitrogen use efficiency in rice genotypes in tropical lowland soils of the State of Tocantins, Brazil

    Directory of Open Access Journals (Sweden)

    Nathan Gonçalves dos Passos

    2015-03-01

    Full Text Available O uso racional de adubação nitrogenada é fundamental para aumentar a produtividade da cultura, assim como reduzir o custo de produção e os riscos de poluição ambiental. Cultivares mais eficientes na absorção e na translocação de nutrientes estão sendo prioridade nos programas de melhoramento, além de que cada vez mais solos pobres são incorporados ao processo de produção agrícola. Assim, objetivou-se, com este trabalho, identificar cultivares melhoradas de arroz, eficientes quanto ao uso de nitrogênio em solos de várzea tropical. As cultivares avaliadas foram BRS-Formoso, Epagri-109, BRSGO-Guará, Metica-1, BRSFronteira, BEST-2000, BRS-Jaburu, BRS-Alvorada, Epagri-116, BRS-Jaçanã, SCSBRS-Piracema, BRSMGOuro Minas, Engopa, IRGA-417 e IRGA-424. Ao simular os ambientes com baixa e alta disponibilidades de nitrogênio, foram aplicadas doses de 20 e 120 kg ha-1 de N, respectivamente. As características analisadas foram altura de plantas, número de panículas por m2, número de dias para maturação, índice de clorofilas a e b e total, massa de 100 grãos e produtividade de grãos. Existe variabilidade genética entre as cultivares avaliadas quanto à eficiência ao uso de nitrogênio em solos de várzea. As cultivares BRSMG-Ouro Minas, SCSBRS-Piracema e IRGA-424 são mais eficientes e responsivas à adubação de nitrogênio = The rational use of nitrogen fertilization is essential to not only increase crop productivity, but also to reduce production costs and risks of environmental pollution. Cultivars more efficient at absorption and translocation of nutrients are taking priority in breeding programs, as well as the poor soils are being increasingly incorporated into the agricultural production process. Thus, the objective of this study was to identify improved cultivars of rice on the efficient use of nitrogen in tropical lowland soils. The evaluated cultivars were BRS-Formoso, Epagri-109, BRSGO-Guará, Metica-1, BRS

  16. "Congo" red: out of Africa?

    Science.gov (United States)

    Steensma, D P

    2001-02-01

    Congo red is the essential histologic stain for demonstrating the presence of amyloidosis in fixed tissues. To the best of my knowledge, nothing has been written about why the stain is named "Congo." To understand the etymology and history of the Congo red histologic stain. Primary sources were consulted extensively, including 19th-century corporate documents, newspapers, legal briefs, patents, memoirs, and scientific papers. Sources were obtained from multiple university libraries and German corporate archives. To Europeans in 1885, the word Congo evoked exotic images of far-off central Africa known as The Dark Continent. The African Congo was also a political flashpoint during the Age of Colonialism. "Congo" red was introduced in Berlin in 1885 as the first of the economically lucrative direct textile dyes. A patent on Congo red was filed by the AGFA Corporation of Berlin 3 weeks after the conclusion of the well-publicized Berlin West Africa Conference. During these important diplomatic talks, German Chancellor Otto von Bismarck presided over a discussion of free trade issues in the Congo River basin. A challenge to AGFA's Congo red patent led to a precedent-setting decision in intellectual property law. The Congo red stain was named "Congo" for marketing purposes by a German textile dyestuff company in 1885, reflecting geopolitical current events of that time.

  17. Microbiological quality of water in a city with persistent and recurrent waterborne diseases under tropical sub-rural conditions: The case of Kikwit City, Democratic Republic of the Congo.

    Science.gov (United States)

    Nienie, Alexis B; Sivalingam, Periyasamy; Laffite, Amandine; Ngelinkoto, Patience; Otamonga, Jean-Paul; Matand, Alphonse; Mulaji, Crispin K; Biey, Emmanuel M; Mpiana, Pius T; Poté, John

    2017-07-01

    The availability of safe drinking water in sub-Saharan countries remains a major challenge because poor sanitation has been the cause of various outbreaks of waterborne disease due to the poor microbiological quality of water used for domestic purposes. The faecal indicator bacteria (FIB) used in the present study included Escherichia coli (E. coli) and Enterococcus (ENT). FIB and aerobic mesophilic bacteria (AMB) were quantified during July 2015 (dry season) and November 2015 (rainy season) in order to assess the quality of drinking water from wells (n=3; P1-P3), and two rivers, the River Lukemi (RLK, n=3) and River Luini (RLN, n=2) in the city of Kikwit, which is located in the province of Kwilu in the Democratic Republic of the Congo. Kikwit is well known for its outbreaks of persistent and recurrent waterborne diseases including Entamoeba, Shigella, typhoid fever, cholera, and Ebola Viral Hemorrhagic Fever. Consequently, E. coli, ENT, and AMB were quantified in water samples according to the standard international methods for water quality determination using the membrane filtration method. The FIB characterization was performed for human-specific Bacteroides by PCR using specific primers. The results obtained revealed high FIB concentrations in river samples collected during both seasons. For example, E. coli respectively reached 4.3×10 4 and 9.2×10 4 CFU 100mL -1 in the dry season and the wet season. ENT reached 5.3×10 3 CFU 100mL -1 during the dry season and 9.8×10 3 CFU 100mL -1 in the wet season. The pollution was significantly worse in the wet season compared to the dry season. Surprisingly, no faecal contamination was observed in well water samples collected in the dry season while E. coli and ENT were detected in all wells in the wet season with values of 6, 7, and 11CFUmL -1 for E. coli in wells P1-P3, respectively and 3, 5, 9 CFU mL -1 for ENT in the same wells. Interestingly, the PCR assays for human-specific Bacteroides HF183/HF134 indicated

  18. How Ebola impacts genetics of Western lowland gorilla populations.

    Science.gov (United States)

    Le Gouar, Pascaline J; Vallet, Dominique; David, Laetitia; Bermejo, Magdalena; Gatti, Sylvain; Levréro, Florence; Petit, Eric J; Ménard, Nelly

    2009-12-18

    Emerging infectious diseases in wildlife are major threats for both human health and biodiversity conservation. Infectious diseases can have serious consequences for the genetic diversity of populations, which could enhance the species' extinction probability. The Ebola epizootic in western and central Africa induced more than 90% mortality in Western lowland gorilla population. Although mortality rates are very high, the impacts of Ebola on genetic diversity of Western lowland gorilla have never been assessed. We carried out long term studies of three populations of Western lowland gorilla in the Republic of the Congo (Odzala-Kokoua National Park, Lossi gorilla sanctuary both affected by Ebola and Lossi's periphery not affected). Using 17 microsatellite loci, we compared genetic diversity and structure of the populations and estimate their effective size before and after Ebola outbreaks. Despite the effective size decline in both populations, we did not detect loss in genetic diversity after the epizootic. We revealed temporal changes in allele frequencies in the smallest population. Immigration and short time elapsed since outbreaks could explain the conservation of genetic diversity after the demographic crash. Temporal changes in allele frequencies could not be explained by genetic drift or random sampling. Immigration from genetically differentiated populations and a non random mortality induced by Ebola, i.e., selective pressure and cost of sociality, are alternative hypotheses. Understanding the influence of Ebola on gorilla genetic dynamics is of paramount importance for human health, primate evolution and conservation biology.

  19. How Ebola impacts genetics of Western lowland gorilla populations.

    Directory of Open Access Journals (Sweden)

    Pascaline J Le Gouar

    2009-12-01

    Full Text Available Emerging infectious diseases in wildlife are major threats for both human health and biodiversity conservation. Infectious diseases can have serious consequences for the genetic diversity of populations, which could enhance the species' extinction probability. The Ebola epizootic in western and central Africa induced more than 90% mortality in Western lowland gorilla population. Although mortality rates are very high, the impacts of Ebola on genetic diversity of Western lowland gorilla have never been assessed.We carried out long term studies of three populations of Western lowland gorilla in the Republic of the Congo (Odzala-Kokoua National Park, Lossi gorilla sanctuary both affected by Ebola and Lossi's periphery not affected. Using 17 microsatellite loci, we compared genetic diversity and structure of the populations and estimate their effective size before and after Ebola outbreaks. Despite the effective size decline in both populations, we did not detect loss in genetic diversity after the epizootic. We revealed temporal changes in allele frequencies in the smallest population.Immigration and short time elapsed since outbreaks could explain the conservation of genetic diversity after the demographic crash. Temporal changes in allele frequencies could not be explained by genetic drift or random sampling. Immigration from genetically differentiated populations and a non random mortality induced by Ebola, i.e., selective pressure and cost of sociality, are alternative hypotheses. Understanding the influence of Ebola on gorilla genetic dynamics is of paramount importance for human health, primate evolution and conservation biology.

  20. The consequences of pleistocene climate change on lowland neotropical vegetation

    Energy Technology Data Exchange (ETDEWEB)

    De Oliveira, P.E.; Colinvaux, P.A. (Smithsonian Tropical Research Institute, Panama City (Panama))

    1994-06-01

    Palynological reconstructions indicate that lowland tropical America was subject to intense cooling during the last ice-age. The descent of presently montane taxa into the lowlands of Amazonia and Minas Gerais indicate temperature depressions ranging from 5[degrees]C to 9[degrees]C cooler-than-present. The strengthened incursion of southerly airmasses caused a reassortment of vegetation throughout Amazonia. Presently allopatric species are found to have been sympatric as novel forest assemblages and formed and dissolved. Modest drying, perhaps a 20% reduction in precipitation, accounts for all the records that show a Pleistocene expansion of savanna. No evidence is found to support the fragmentation of Amazonian forests during glacial times, and the hypothesis of forest refuges as an explanation of tropical speciation is rejected on empirical grounds.

  1. Ecological and distributional notes on hummingbirds from Bolivian lowland forests

    OpenAIRE

    Abrahamczyk, S; Kessler, M

    2010-01-01

    Little is known about the distribution, ecology and behaviour of hummingbirds in the Andean foothills of Bolivia, where many lowland hummingbird species reach their south-western distributional limits. In November 2007 – October 2008, we surveyed hummingbirds at six sites along a 660-km transect, from tropical Amazonian humid forest to subtropical spiny forest of the Gran Chaco. In total, we found 21 hummingbird species. For ten of these, we provide new information on latitudinal and eleva...

  2. Country Presentation Congo

    International Nuclear Information System (INIS)

    Mwata, P.K.; SAKI, A.; KAZADI, J.

    2010-01-01

    Illicit trafficking of radioactive minerals, precious metals and nuclear materials is generally expanded practice in some parts of the Democratic Republic of Congo. The phenomenon took place early in 1990 and amplified from 1998. The main causes of this practice are political instability that led to general poverty among population and the lack of legal framework governing the exploitation of minerals. Nuclear Illicit trafficking in Congo concerns radioactive mineral sand precious metals in eastern and southern parts of the country. The unfavorable political environment that took place in Congo in the 1990s resulted in local manpower and mine workers immigrating to neighboring countries. A great fraction of these new jobless started exploiting abandoned mines residues searching for Cu, Co and Au for survival. First cases of illicit exploitation of uranium minerals were reported very soon after rock sliding that occurred in 2004 on Shinkolobwe site in Katanga region. This uncontrolled mineral exploitation got worse when several mining companies were licensed by GECAMINES company to explore, exploit, purchase minerals from individuals and export raw materials and concentrates.

  3. A-B-O and Rh affinities between highland and lowland Quechua-speaking Peruvian populations.

    Science.gov (United States)

    Frisancho, A R; Klayman, J E

    1975-09-01

    According to the accounts of the Spanish chronicles and various historical analyses the Quechua-speaking population inhabiting the Province of Lamas in the Eastern Tropical Lowlands of Peru are descendants of the Chanca Tribes that migrated from the highlands about 500 years ago. The results of the present study indicate that in terms of the A-B-O and Rh systems the lowland Quechua-speaking population from the Province of Lamas and the highland Quechua population from the Province of Junin are more similar to each other than to other tropical tribes. Therefore, it is quite possible that the present lowland Quechua-speaking population from the Province of Lamas may be descendants of Andean populations.

  4. Will Passive Protection Save Congo Forests?

    Science.gov (United States)

    Galford, Gillian L.; Soares-Filho, Britaldo S.; Sonter, Laura J.; Laporte, Nadine

    2015-01-01

    Central Africa’s tropical forests are among the world’s largest carbon reserves. Historically, they have experienced low rates of deforestation. Pressures to clear land are increasing due to development of infrastructure and livelihoods, foreign investment in agriculture, and shifting land use management, particularly in the Democratic Republic of Congo (DRC). The DRC contains the greatest area of intact African forests. These store approximately 22 billion tons of carbon in aboveground live biomass, yet only 10% are protected. Can the status quo of passive protection — forest management that is low or nonexistent — ensure the preservation of this forest and its carbon? We have developed the SimCongo model to simulate changes in land cover and land use based on theorized policy scenarios from 2010 to 2050. Three scenarios were examined: the first (Historical Trends) assumes passive forest protection; the next (Conservation) posits active protection of forests and activation of the national REDD+ action plan, and the last (Agricultural Development) assumes increased agricultural activities in forested land with concomitant increased deforestation. SimCongo is a cellular automata model based on Bayesian statistical methods tailored for the DRC, built with the Dinamica-EGO platform. The model is parameterized and validated with deforestation observations from the past and runs the scenarios from 2010 through 2050 with a yearly time step. We estimate the Historical Trends trajectory will result in average emissions of 139 million t CO2 year-1 by the 2040s, a 15% increase over current emissions. The Conservation scenario would result in 58% less clearing than Historical Trends and would conserve carbon-dense forest and woodland savanna areas. The Agricultural Development scenario leads to emissions of 212 million t CO2 year-1 by the 2040s. These scenarios are heuristic examples of policy’s influence on forest conservation and carbon storage. Our results

  5. Diversification of tanagers, a species rich bird group, from lowlands to montane regions of South America

    DEFF Research Database (Denmark)

    Fjeldså, Jon; Rahbek, Carsten

    2006-01-01

    in the Atlantic forests of south-eastern Brazil, and moderate densities of widespread species in the tropical lowlands. Contemporary climate explains well the variation in species richness for the 25% most widespread species; for the remaining 75% of species with more restricted distributions, variation can only...

  6. Patterns and determinants of floristic variation across lowland forests of Bolivia. Biotropica

    NARCIS (Netherlands)

    Toledo, M.; Poorter, L.; Peña-Claros, M.; Alarcón, A.; Balcázar, J.; Chuviña, J.; Leaño, C.; Licona, J.C.; Steege, ter H.; Bongers, F.

    2011-01-01

    Floristic variation is high in the Neotropics, but little is known about the factors shaping this variation at the mesoscale. We examined floristic composition and its relationship with environmental factors across 220 1-ha permanent plots in tropical lowland Bolivia. For each plot, abundance of 100

  7. Palm harvest impact in the western Amazon, Andes and Pacific lowlands

    DEFF Research Database (Denmark)

    Balslev, Henrik

    2011-01-01

    Palms are the most useful group of plants in tropical American forests and in this project we study the effect of extraction and trade of palms on forests in the western Amazon, Andes, and Pacific lowlands. We determine the size of the resource by making palm community studies in the different...

  8. Evaluating barriers to native seedling establishment in an invaded Hawaiian lowland wet forest

    Science.gov (United States)

    S. Cordell; R. Ostertag; B. Rowe; L. Sweinhart; L. Vasquez-Radonic; J. Michaud; T.C. Cole; J.R. Schulten

    2009-01-01

    Many tropical island forest ecosystems are dominated by non-native plant species and lack native species regeneration in the understorey. Comparison of replicated control and removal plots offers an opportunity to examine not only invasive species impacts but also the restoration potential of native species. In lowland Hawaiian wet forests little is known about native...

  9. Lesula: a new species of Cercopithecus monkey endemic to the Democratic Republic of Congo and implications for conservation of Congo's central basin.

    Directory of Open Access Journals (Sweden)

    John A Hart

    Full Text Available In June 2007, a previously undescribed monkey known locally as "lesula" was found in the forests of the middle Lomami Basin in central Democratic Republic of Congo (DRC. We describe this new species as Cercopithecus lomamiensis sp. nov., and provide data on its distribution, morphology, genetics, ecology and behavior. C. lomamiensis is restricted to the lowland rain forests of central DRC between the middle Lomami and the upper Tshuapa Rivers. Morphological and molecular data confirm that C. lomamiensis is distinct from its nearest congener, C. hamlyni, from which it is separated geographically by both the Congo (Lualaba and the Lomami Rivers. C. lomamiensis, like C. hamlyni, is semi-terrestrial with a diet containing terrestrial herbaceous vegetation. The discovery of C. lomamiensis highlights the biogeographic significance and importance for conservation of central Congo's interfluvial TL2 region, defined from the upper Tshuapa River through the Lomami Basin to the Congo (Lualaba River. The TL2 region has been found to contain a high diversity of anthropoid primates including three forms, in addition to C. lomamiensis, that are endemic to the area. We recommend the common name, lesula, for this new species, as it is the vernacular name used over most of its known range.

  10. Production of animal protein in the Congo Basin, a challenge for the future of people and wildlife

    OpenAIRE

    Moula, Nassim; Hornick, Jean-Luc; Ruppol, Patrick; Antoine-Moussiaux, Nicolas; Leroy, Pascal

    2014-01-01

    Protein needs are considerable in the Congo Basin, a vast territory dominated by forest and inhabited by tens of millions of people. Whereas over 85% of the DRC’s population of the Basin live in the forest, the situation is different in other countries where the majority is urban (Cameroon, Central African Republic, Congo and Gabon). This paper presents several achievements of the Centre for Tropical Agriculture and Veterinary Medicine in Kinshasa (CAVTK), which aims since 2001 to conduct pil...

  11. Looking closer at the Congo

    DEFF Research Database (Denmark)

    Jansson, Johanna; Jiang, Wenran

    2011-01-01

    An NGO report on Chinese investment in the Democratic Republic of Congo opens a vital debate, but its methodology leaves the reader wanting a fuller version of the facts, write Johanna Jansson and Jiang Wenran.......An NGO report on Chinese investment in the Democratic Republic of Congo opens a vital debate, but its methodology leaves the reader wanting a fuller version of the facts, write Johanna Jansson and Jiang Wenran....

  12. Modelling the Congo basin ecosystems with a dynamic vegetation model

    Science.gov (United States)

    Dury, Marie; Hambuckers, Alain; Trolliet, Franck; Huynen, Marie-Claude; Haineaux, Damien; Fontaine, Corentin M.; Fayolle, Adeline; François, Louis

    2014-05-01

    The scarcity of field observations in some parts of the world makes difficult a deep understanding of some ecosystems such as humid tropical forests in Central Africa. Therefore, modelling tools are interesting alternatives to study those regions even if the lack of data often prevents sharp calibration and validation of the model projections. Dynamic vegetation models (DVMs) are process-based models that simulate shifts in potential vegetation and its associated biogeochemical and hydrological cycles in response to climate. Initially run at the global scale, DVMs can be run at any spatial scale provided that climate and soil data are available. In the framework of the BIOSERF project ("Sustainability of tropical forest biodiversity and services under climate and human pressure"), we use and adapt the CARAIB dynamic vegetation model (Dury et al., iForest - Biogeosciences and Forestry, 4:82-99, 2011) to study the Congo basin vegetation dynamics. The field campaigns have notably allowed the refinement of the vegetation representation from plant functional types (PFTs) to individual species through the collection of parameters such as the specific leaf area or the leaf C:N ratio of common tropical tree species and the location of their present-day occurrences from literature and available database. Here, we test the model ability to reproduce the present spatial and temporal variations of carbon stocks (e.g. biomass, soil carbon) and fluxes (e.g. gross and net primary productivities (GPP and NPP), net ecosystem production (NEP)) as well as the observed distribution of the studied species over the Congo basin. In the lack of abundant and long-term measurements, we compare model results with time series of remote sensing products (e.g. vegetation leaf area index (LAI), GPP and NPP). Several sensitivity tests are presented: we assess consecutively the impacts of the level at which the vegetation is simulated (PFTs or species), the spatial resolution and the initial land

  13. Congo grass grown in rotation with soybean affects phosphorus bound to soil carbon

    Directory of Open Access Journals (Sweden)

    Alexandre Merlin

    2014-06-01

    Full Text Available The phosphorus supply to crops in tropical soils is deficient due to its somewhat insoluble nature in soil, and addition of P fertilizers has been necessary to achieve high yields. The objective of this study was to examine the mechanisms through which a cover crop (Congo grass - Brachiaria ruziziensis in rotation with soybean can enhance soil and fertilizer P availability using long-term field trials and laboratory chemical fractionation approaches. The experimental field had been cropped to soybean in rotation with several species under no-till for six years. An application rate of no P or 240 kg ha-1 of P2O5 had been applied as triple superphosphate or as Arad rock phosphate. In April 2009, once more 0.0 or 80.0 kg ha-1 of P2O5 was applied to the same plots when Congo grass was planted. In November 2009, after Congo grass desiccation, soil samples were taken from the 0-5 and 5-10 cm depth layer and soil P was fractionated. Soil-available P increased to the depth of 10 cm through growing Congo grass when P fertilizers were applied. The C:P ratio was also increased by the cover crop. Congo grass cultivation increased P content in the soil humic fraction to the depth of 10 cm. Congo grass increases soil P availability by preventing fertilizer from being adsorbed and by increasing soil organic P.

  14. Ectomycorrhizal fungi in Amazonian tropical forests in Colombia

    NARCIS (Netherlands)

    Vasco Palacios, A.M.

    2016-01-01

    The ectomycorrhizal (EcM) symbiosis was assumed to be restricted to the temperate regions where forests are dominated by EcM host plants, and the tropics were supposed to be dominated by endomycorrhizal fungi. However, evidence of the presence of EcM symbiosis in tropical lowland ecosystems has been

  15. Neotropical lowland forests along environmental gradients

    NARCIS (Netherlands)

    Toledo, M.

    2010-01-01

    Neotropical lowlands feature an extraordinary display of vegetation types. This is especially the case for Bolivia where three biogeographical regions, Amazonian, Brazilian-Paranaense and Gran Chaco meet in the lowland areas, providing thus an ideal setting to study vegetation-environment

  16. Complementarity and efficiency of bat capture methods in a lowland tropical dry forest of Yucatán, Mexico Complementariedad y eficiencia de métodos de captura de murciélagos en una selva baja caducifolia de Yucatán, México

    Directory of Open Access Journals (Sweden)

    Juan M. Pech-Canche

    2011-09-01

    Full Text Available The combined use of different methods for surveying bat assemblages has increased over the last few decades. The objective of this study was to assess the efficiency of bat inventories by comparing assemblages parameters (species richness, abundance and composition using the 3 most conventional capture methods (ground-level and sub-canopy mist nets and harp traps, in a lowland tropical dry forest in Yucatán, Mexico. In ground mist nets, only phyllostomid species were recorded, principally frugivorous and nectarivorous species, while in harp traps the majority were insectivorous species from other families. Our results indicate that for the order Chiroptera the most efficient combination of capture methods is the simultaneous use of ground mist nets and harp traps. However, an inventory of Phyllostomidae is reliably achieved with only ground mist nets. Also, a combination of ground and sub-canopy mist nets does not provide an efficient sampling strategy.El uso combinado de diferentes métodos de muestreo de ensambles de murciélagos se ha incrementado en las últimas décadas. El objetivo de este estudio fue evaluar la eficiencia de los inventarios de murciélagos comparando los parámetros del ensamble (riqueza de especies, abundancia y composición usando los 3 métodos de captura convencionales (redes de niebla a nivel de sotobosque y sub-dosel, y trampas arpa, en una selva baja caducifolia de Yucatán, México. En las redes de sotobosque se registraron solamente especies de filostómidos, principalmente especies frugívoras y nectarívoras; mientras que en las trampas arpa, la mayoría fueron especies insectívoras de otras familias. Nuestros resultados indican que para el orden Chiroptera la combinación más eficiente de métodos de captura es el uso simultáneo de redes de sotobosque y trampas arpa. Sin embargo, se alcanza un inventario confiable de filostómidos sólo con las redes de sotobosque. Además, una combinación de redes de

  17. The petroleum economy of the Congo

    International Nuclear Information System (INIS)

    Gualbert-Brice Massengo, Ph.D.

    2005-01-01

    The author aims to explain the petroleum phenomena in Congo as a contribution to the truth. The Congo petroleum experience can be seen as a lesson for the next generations and for the other african countries. The Congo Brazzaville, a little country by its population and well equipped in natural and human resources, is become meanwhile a non security area for its inhabitants because of a decreasing economy and a continuous political crisis. (A.L.B.)

  18. Deforestation scenarios for the Bolivian lowlands.

    Science.gov (United States)

    Tejada, Graciela; Dalla-Nora, Eloi; Cordoba, Diana; Lafortezza, Raffaele; Ovando, Alex; Assis, Talita; Aguiar, Ana Paula

    2016-01-01

    Tropical forests in South America play a key role in the provision of ecosystem services such as carbon sinks, biodiversity conservation, and global climate regulation. In previous decades, Bolivian forests have mainly been deforested by the expansion of agricultural frontier development, driven by the growing demands for beef and other productions. In the mid-2000s the Movimiento al Socialismo (MAS) party rose to power in Bolivia with the promise of promoting an alternative development model that would respect the environment. The party passed the world's first laws granting rights to the environment, which they termed Mother Earth (Law No. 300 of 2012), and proposed an innovative framework that was expected to develop radical new conservation policies. The MAS conservationist discourse, policies, and productive practices, however, have since been in permanent tension. The government continues to guarantee food production through neo-extractivist methods by promoting the notion to expand agriculture from 3 to 13 million ha, risking the tropical forests and their ecosystem services. These actions raise major environmental and social concerns, as the potential impacts of such interventions are still unknown. The objective of this study is to explore an innovative land use modeling approach to simulate how the growing demand for land could affect future deforestation trends in Bolivia. We use the LuccME framework to create a spatially-explicit land cover change model and run it under three different deforestation scenarios, spanning from the present-2050. In the Sustainability scenario, deforestation reaches 17,703,786 ha, notably in previously deforested or degraded areas, while leaving forest extensions intact. In the Middle of the road scenario, deforestation and degradation move toward new or paved roads spreading across 25,698,327 ha in 2050, while intact forests are located in Protected Areas (PAs). In the Fragmentation scenario, deforestation expands to almost

  19. Cardiovascular evaluation of lowland gorillas

    International Nuclear Information System (INIS)

    Junge, R.E.; Mezei, L.E.; Muhlbauer, M.C.; Weber, M.

    1998-01-01

    To design a diagnostic protocol that uses appropriate techniques, including ultrasonography, to assess cardiovascular health and detect primary cardiac diseases in gorillas and to establish a database of reference values for cardiac measurements in clinically normal gorillas. Prospective study. 5 adult male lowland gorillas from 11 to 18 years old. A complete cardiac evaluation was performed on anesthetized gorillas, including physical examination, thoracic radiography, electrocardiography, echocardiography, blood pressure determination, CBC, serum biochemical analyses, and serologic assay for viral diseases. Standard cardiac measurements were made from images collected during ultrasonography. Cardiac measurements derived from ultrasonographic images were consistent with those considered normal in human beings. Results of other diagnostic tests were also considered normal. Cardiac disease is the primary cause of mortality in old captive gorillas. The technique used here provided excellent evaluation of cardiac function. Use of these techniques will allow early detection of cardiac disease, making treatment or medical management possible

  20. Population dynamics of Rodents and Insectivores in lowland tropical ...

    African Journals Online (AJOL)

    ADOWIE PERE

    2018-03-19

    Mar 19, 2018 ... ecosystem of Okomu National Park, Edo State, Nigeria. OMOGBEME, MI; OKE, CO. Department of Animal and Environmental Biology, University of Benin, P.M.B 1154, Benin City, Nigeria. ..... University Press ... IUCN (2017).

  1. Population dynamics of Rodents and Insectivores in lowland tropical ...

    African Journals Online (AJOL)

    ADOWIE PERE

    2018-03-19

    Mar 19, 2018 ... (abdominal or scrotal testes in males and enlarged nipples in females), and ... abundance is dominated by family Muridae with 544. (74%) individuals .... captured during the dry season accounting for 5.41% of the total capture ...

  2. Internasional Symposium On Lowland Technology (ISLT 2012) SUbstainability of Lowlands to Climated Change and Natural Disasters

    OpenAIRE

    Lawalenna

    2011-01-01

    ???Lowland??? denotes regions of low elevation, which are particularly vulnerable to climatic and environmental changes. For example, global warming, which appears to be causing a rise in sea level, must ultimately affect the safety of coastal dikes and other coastal infrastructures, as well as threaten the water and ecological systems in lowland areas. Lowland regions are also particularly susceptible to natural disasters. Action is now required for the development of new tech...

  3. Re-Meandering of Lowland Streams

    DEFF Research Database (Denmark)

    Pedersen, Morten Lauge; Kristensen, Klaus Kevin; Friberg, Nikolai

    2014-01-01

    We evaluated the restoration of physical habitats and its influence on macroinvertebrate community structure in 18 Danish lowland streams comprising six restored streams, six streams with little physical alteration and six channelized streams. We hypothesized that physical habitats and macroinver...

  4. Foreign capital, forest change and regulatory compliance in Congo Basin forests

    International Nuclear Information System (INIS)

    Brandt, Jodi S; Nolte, Christoph; Agrawal, Arun; Steinberg, Jessica

    2014-01-01

    Tropical forest change is driven by demand in distant markets. Equally, investments in tropical forest landscapes by capital originating from distant emerging economies are on the rise. Understanding how forest outcomes vary by investment source is therefore becoming increasingly important. We empirically evaluate the relationship between investment source and deforestation from 2000 to 2010 in the Republic of Congo. A Congolese forestry code was implemented in 2000 to mitigate degradation of production forests by standardizing all logging in the country according to sustainable forest management (SFM) guidelines. Following the implementation of this law, the majority (73%) of Congo’s production forests were managed by European (40%) and Asian (33%) companies. European concessions had the highest rates of total and core deforestation, followed by Asian concessions, indicating that the fragmentation of intact forests in Congo is strongly associated with industrial logging fueled by foreign capital. European concession holders were also far more likely to comply with SFM policies, followed by Asian concessions, suggesting that compliance with Sustainable Forest Management policies may not mitigate degradation in tropical production forests. Further evaluation of the relationship between investment source, regulatory compliance, and outcomes in tropical countries is essential for effective conservation of tropical forest ecosystems. (paper)

  5. Foreign capital, forest change and regulatory compliance in Congo Basin forests

    Science.gov (United States)

    Brandt, Jodi S.; Nolte, Christoph; Steinberg, Jessica; Agrawal, Arun

    2014-04-01

    Tropical forest change is driven by demand in distant markets. Equally, investments in tropical forest landscapes by capital originating from distant emerging economies are on the rise. Understanding how forest outcomes vary by investment source is therefore becoming increasingly important. We empirically evaluate the relationship between investment source and deforestation from 2000 to 2010 in the Republic of Congo. A Congolese forestry code was implemented in 2000 to mitigate degradation of production forests by standardizing all logging in the country according to sustainable forest management (SFM) guidelines. Following the implementation of this law, the majority (73%) of Congo’s production forests were managed by European (40%) and Asian (33%) companies. European concessions had the highest rates of total and core deforestation, followed by Asian concessions, indicating that the fragmentation of intact forests in Congo is strongly associated with industrial logging fueled by foreign capital. European concession holders were also far more likely to comply with SFM policies, followed by Asian concessions, suggesting that compliance with Sustainable Forest Management policies may not mitigate degradation in tropical production forests. Further evaluation of the relationship between investment source, regulatory compliance, and outcomes in tropical countries is essential for effective conservation of tropical forest ecosystems.

  6. Land, Water and Society in the Maya Lowlands

    Science.gov (United States)

    Murtha, T.; French, K.; Duffy, C.; Webster, D.

    2013-12-01

    This paper reports the results of our project investigating the long-term spatial and temporal dynamics of land use management, agricultural decision-making and patterns of resource availability in the tropical lowlands of Central America. Overall, our project combines diachronic environmental simulation with historic settlement pattern survey to address a series of long-standing questions about the coupled natural and human (CNH) landscape history in the Central Maya lowlands (at the UNESCO world heritage site of Tikal in the Maya Biosphere Reserve). The paper describes the preliminary results of our project, including changing patterns of land, water, settlement and political history using climate, soil and hydrologic modeling and time series spatial analysis of population and settlement patterns. The critical period of the study, 1000 BC until the present, begins with dispersed settlements accompanied by widespread deforestation and soil erosion. Population size and density grows rapidly for 800 years, while deforestation and erosion rates decline; however, there is striking evidence of political evolution during this period, including the construction of monumental architecture, hieroglyphic monuments detailing wars and alliances, and the construction of a defensive earthwork feature, signaling political territories and possibly delineating natural resource boundaries. Population decline and steady reforestation followed until more recent migration into the region, which has impacted the biosphere ecology. Building on our previous research regionally and comparative research completed in Belize and Mexico, we are modeling sample periods the 3,000-year landscape history of the region, comparing land and water availability to population distributions and what we know about political history. Simulations are generated using historic climate and land use data, primarily relying on the Erosion Productivity Impact Calculator (EPIC) and the Penn State Integrated

  7. Postcolonial Hybrids in The Lowland

    Directory of Open Access Journals (Sweden)

    Seyedeh Zahra Ghoreishi

    2016-04-01

    Full Text Available This paper delves into Jhumpa Lahiri’s 2013 novel, The Lowland, to analyze the diasporic experience of the Indian-born characters. Homi Bhabha’s postcolonial approach is utilized to demonstrate the ways in which the characters perceive the immigration experience, and to unravel the causes of their despair, the disintegration of their family, and the underlying reasons behind the decisions that they make to compensate for their marginal status in the adopted land. It is attempted to shed light on the characters’ insecurities and mental challenges brought forth by their ‘liminal’ condition, in which they find themselves caught in a dilemma between the Indian lifestyle on the one hand, and the American dominant culture, on the other. Furthermore, ‘hybridity’ is discussed, which entails the characters’ partial adoption of the foreign culture that gives birth to mixed identities in the ‘third space.’ This research concludes that in spite of the disturbing aspects of diasporic life including uncertainty, marginality, and unbelonging over which the characters possess no control, they are capable of surviving and even flourishing in the foreign social milieu. Keywords: Adopted Land; Diaspora; Liminality; Hybridity; Third Space

  8. To Tip or Not to Tip: The Case of the Congo Basin Rainforest Realm

    Science.gov (United States)

    Pietsch, S.; Bednar, J. E.; Fath, B. D.; Winter, P. A.

    2017-12-01

    The future response of the Congo basin rainforest, the second largest tropical carbon reservoir, to climate change is still under debate. Different Climate projections exist stating increase and decrease in rainfall and different changes in rainfall patterns. Within this study we assess all options of climate change possibilities to define the climatic thresholds of Congo basin rainforest stability and assess the limiting conditions for rainforest persistence. We use field data from 199 research plots from the Western Congo basin to calibrate and validate a complex BioGeoChemistry model (BGC-MAN) and assess model performance against an array of possible future climates. Next, we analyze the reasons for the occurrence of tipping points, their spatial and temporal probability of occurrence, will present effects of hysteresis and derive probabilistic spatial-temporal resilience landscapes for the region. Additionally, we will analyze attractors of forest growth dynamics and assess common linear measures for early warning signals of sudden shifts in system dynamics for their robustness in the context of the Congo Basin case, and introduce the correlation integral as a nonlinear measure of risk assessment.

  9. Statistics of Deep Convection in the Congo Basin Derived From High-Resolution Simulations.

    Science.gov (United States)

    White, B.; Stier, P.; Kipling, Z.; Gryspeerdt, E.; Taylor, S.

    2016-12-01

    Convection transports moisture, momentum, heat and aerosols through the troposphere, and so the temporal variability of convection is a major driver of global weather and climate. The Congo basin is home to some of the most intense convective activity on the planet and is under strong seasonal influence of biomass burning aerosol. However, deep convection in the Congo basin remains under studied compared to other regions of tropical storm systems, especially when compared to the neighbouring, relatively well-understood West African climate system. We use the WRF model to perform a high-resolution, cloud-system resolving simulation to investigate convective storm systems in the Congo. Our setup pushes the boundaries of current computational resources, using a 1 km grid length over a domain covering millions of square kilometres and for a time period of one month. This allows us to draw statistical conclusions on the nature of the simulated storm systems. Comparing data from satellite observations and the model enables us to quantify the diurnal variability of deep convection in the Congo basin. This approach allows us to evaluate our simulations despite the lack of in-situ observational data. This provides a more comprehensive analysis of the diurnal cycle than has previously been shown. Further, we show that high-resolution convection-permitting simulations performed over near-seasonal timescales can be used in conjunction with satellite observations as an effective tool to evaluate new convection parameterisations.

  10. Congo Basin rainfall climatology: can we believe the climate models?

    Science.gov (United States)

    Washington, Richard; James, Rachel; Pearce, Helen; Pokam, Wilfried M; Moufouma-Okia, Wilfran

    2013-01-01

    The Congo Basin is one of three key convective regions on the planet which, during the transition seasons, dominates global tropical rainfall. There is little agreement as to the distribution and quantity of rainfall across the basin with datasets differing by an order of magnitude in some seasons. The location of maximum rainfall is in the far eastern sector of the basin in some datasets but the far western edge of the basin in others during March to May. There is no consistent pattern to this rainfall distribution in satellite or model datasets. Resolving these differences is difficult without ground-based data. Moisture flux nevertheless emerges as a useful variable with which to study these differences. Climate models with weak (strong) or even divergent moisture flux over the basin are dry (wet). The paper suggests an approach, via a targeted field campaign, for generating useful climate information with which to confront rainfall products and climate models.

  11. Linking plant functional traits and forest carbon stocks in the Congo Basin

    Science.gov (United States)

    Kearsley, Elizabeth; Verbeeck, Hans; Hufkens, Koen; Lewis, Simon; Huygens, Dries; Beeckman, Hans; Steppe, Kathy; Boeckx, Pascal

    2013-04-01

    Accurate estimates of the amount of carbon stored in tropical forests represent crucial baseline data for recent climate change mitigation policies. Such data are needed to quantify possible emissions due to deforestation and forest degradation, and to evaluate the potential of these forests to act as carbon sinks. Currently, only rough estimates of the carbon stocks for Central African tropical forests are available due to a lack of field data, and little is known about the response of these stocks to climate change. We present the first ground-based carbon stock data for the central Congo Basin in Yangambi, D. R. Congo, based on data of 20 inventory plots of 1 ha covering different forest types. We found an average aboveground carbon stock of 163 ± 19 Mg C ha-1 for intact old-growth forest, which is significantly lower than the stocks recorded in the outer regions of the Congo Basin. Commonly studied drivers for variations of carbon stocks include climatic and edaphic factors, but detailed trait-based studies are lacking. We identified a significant difference in height-diameter relations across the Congo Basin as a driver for spatial differences in carbon stocks. The study of a more detailed interaction of the environment and the available tree species pool as drivers for differences in carbon storage could have large implications. The effect of the species pool on carbon storage can be large since species differ in their ability to sequester carbon, and the collective functional characteristics of plant communities could be a major driver of carbon accumulation. The use of a trait-based approach shows high potential for identifying and quantifying carbon stocks as an ecosystem service. We test for associations between functional trait values and carbon storage across multiple regrowth and old-growth forests types in the Yangambi study area, with soil properties and climate similar for all plots. A selection of traits associated with carbon dynamics is made

  12. Food transfers in immature wild western lowland gorillas (Gorilla gorilla gorilla).

    Science.gov (United States)

    Nowell, Angela A; Fletcher, Alison W

    2006-10-01

    The transfer of food items between individuals has been described in primates as serving an informative purpose in addition to supplementing the diet of immature individuals. This behaviour has yet to be described in western lowland gorillas (Gorilla gorilla gorilla), and results are presented here of observations of food transfers in immature gorillas at Mbeli Bai, Republic of Congo. The frequency of food transfers decreased with increasing immature age, while the frequency of independent feeding and processing of food increased. Transfers between mothers and infants were the most frequent, with infants attempting to take items from the mother. These attempts were not always successful and the item was relinquished on less than 50% of attempts. Mothers also took items from their offspring. The results point to the functional significance of food transfers in western lowland gorillas being informational. In a bai environment, where one species forms the majority of a visiting gorilla's diet despite other species being available, the initiation of food transfers by immatures is proposed to serve the purpose of familiarising them with which species, and which parts of those species, may be eaten.

  13. Forest structure in low diversity tropical forests: a study of Hawaiian wet and dry forests

    Science.gov (United States)

    R. Ostertag; F. Inman-Narahari; S. Cordell; C.P. Giardina; L. Sack

    2014-01-01

    The potential influence of diversity on ecosystem structure and function remains a topic of significant debate, especially for tropical forests where diversity can range widely. We used Center for Tropical Forest Science (CTFS) methodology to establish forest dynamics plots in montane wet forest and lowland dry forest on Hawai‘i Island. We compared the species...

  14. Crimean-Congo Hemorrhagic Fever

    Directory of Open Access Journals (Sweden)

    Emadi Koochak H

    2003-10-01

    Full Text Available Crimean-Congo hemorrhagic fever (CCHF was first described in the Crimea in 1944 and then in 1956 in congo. CCHF is a viral hemorrhagic fever of the Nairovirus group that belongs to Bunyaviridae family virus. It is transmitted to human by tick bite. The most efficient and common tick that is the vectors of CCHF is a member of the Hyalomma genus which infected many mammals such as livestock, this tick is the main reservoire of virus in nature. Humans also become infected with CCHF virus by direct contact with blood or other infected tissues from livestock or human patients (nosocomial infection. Disease has been found in saharic Africa, Eastern Europe, Pakistan, India and Middle East (specially Iran and Iraq. This disease recently spread in Iran so in 1999 to 2001 at least 222 suspected case(81 definite case reported that led to the death of 15 of 81 cases. It is estimated that 30 percent of the country's cattle are contaminated with this virus."nIn humans, after a short incubation period it appears suddenly with fever, chills, myalgia and GI symptoms followed by severe bleeding and DIC that led to death .If the patient improved, has a long {2-4 weeks convalescence period. Disease diagnosed by clinical manifestations, serologic tests, viral culture and PCR and its specific treatment is oral ribavirin for 10 days, for prevention of disease personal protective measures from tick bite, spraying poison of mews to reduce of ticks crowd, isolation of patients and dis-infection of contaminated personal equipments that who suffering from CCHF is recommended.

  15. Lowland forest butterflies of the Sankosh River catchment, Bhutan

    Directory of Open Access Journals (Sweden)

    A.P. Singh

    2012-10-01

    a good potential for ecotourism. Establishment of a butterfly conservatory and park as a ‘biodiversity offset’ for conservation of ‘rare’ species along with more field surveys in the study area will be a way forward along with the present work to bridge the exisiting gaps in knowledge on butterflies of the sub-tropical lowland forests of the Himalayas.

  16. Organism-substrate relationships in lowland streams

    NARCIS (Netherlands)

    Tolkamp, H.H.

    1980-01-01

    A field and laboratory study on the microdistribution of bottom dwelling macroinvertebrates to investigate the role of the stream substrate In the development and preservation of the macroinvertebrate communities in natural, undisturbed lowland streams is described. Field data on bottom substrates

  17. Directional layouts in central lowland Maya settlement

    DEFF Research Database (Denmark)

    Bevan, Andrew; Jobbová, Eva; Helmke, Christophe

    2013-01-01

    This paper suggests the existence of non-random, directional patterns in the location of housemounds across the Late Classic Maya settlement landscape at Baking Pot, Belize, and then explores the wider implications of this patterning in the central Maya lowlands. It introduces an anisotropic method...

  18. Widespread Forest Vertebrate Extinctions Induced by a Mega Hydroelectric Dam in Lowland Amazonia.

    Science.gov (United States)

    Benchimol, Maíra; Peres, Carlos A

    2015-01-01

    Mega hydropower projects in tropical forests pose a major emergent threat to terrestrial and freshwater biodiversity worldwide. Despite the unprecedented number of existing, under-construction and planned hydroelectric dams in lowland tropical forests, long-term effects on biodiversity have yet to be evaluated. We examine how medium and large-bodied assemblages of terrestrial and arboreal vertebrates (including 35 mammal, bird and tortoise species) responded to the drastic 26-year post-isolation history of archipelagic alteration in landscape structure and habitat quality in a major hydroelectric reservoir of Central Amazonia. The Balbina Hydroelectric Dam inundated 3,129 km2 of primary forests, simultaneously isolating 3,546 land-bridge islands. We conducted intensive biodiversity surveys at 37 of those islands and three adjacent continuous forests using a combination of four survey techniques, and detected strong forest habitat area effects in explaining patterns of vertebrate extinction. Beyond clear area effects, edge-mediated surface fire disturbance was the most important additional driver of species loss, particularly in islands smaller than 10 ha. Based on species-area models, we predict that only 0.7% of all islands now harbor a species-rich vertebrate assemblage consisting of ≥80% of all species. We highlight the colossal erosion in vertebrate diversity driven by a man-made dam and show that the biodiversity impacts of mega dams in lowland tropical forest regions have been severely overlooked. The geopolitical strategy to deploy many more large hydropower infrastructure projects in regions like lowland Amazonia should be urgently reassessed, and we strongly advise that long-term biodiversity impacts should be explicitly included in pre-approval environmental impact assessments.

  19. Widespread Forest Vertebrate Extinctions Induced by a Mega Hydroelectric Dam in Lowland Amazonia.

    Directory of Open Access Journals (Sweden)

    Maíra Benchimol

    Full Text Available Mega hydropower projects in tropical forests pose a major emergent threat to terrestrial and freshwater biodiversity worldwide. Despite the unprecedented number of existing, under-construction and planned hydroelectric dams in lowland tropical forests, long-term effects on biodiversity have yet to be evaluated. We examine how medium and large-bodied assemblages of terrestrial and arboreal vertebrates (including 35 mammal, bird and tortoise species responded to the drastic 26-year post-isolation history of archipelagic alteration in landscape structure and habitat quality in a major hydroelectric reservoir of Central Amazonia. The Balbina Hydroelectric Dam inundated 3,129 km2 of primary forests, simultaneously isolating 3,546 land-bridge islands. We conducted intensive biodiversity surveys at 37 of those islands and three adjacent continuous forests using a combination of four survey techniques, and detected strong forest habitat area effects in explaining patterns of vertebrate extinction. Beyond clear area effects, edge-mediated surface fire disturbance was the most important additional driver of species loss, particularly in islands smaller than 10 ha. Based on species-area models, we predict that only 0.7% of all islands now harbor a species-rich vertebrate assemblage consisting of ≥80% of all species. We highlight the colossal erosion in vertebrate diversity driven by a man-made dam and show that the biodiversity impacts of mega dams in lowland tropical forest regions have been severely overlooked. The geopolitical strategy to deploy many more large hydropower infrastructure projects in regions like lowland Amazonia should be urgently reassessed, and we strongly advise that long-term biodiversity impacts should be explicitly included in pre-approval environmental impact assessments.

  20. Effects of phosphorus and nitrogen additions on tropical soil microbial activity in the context of experimental warming

    Science.gov (United States)

    Foley, M.; Nottingham, A.; Turner, B. L.

    2017-12-01

    Soil warming is generally predicted to increase microbial mineralization rates and accelerate soil C losses which could establish a positive feedback to climatic warming. Tropical rain forests account for a third of global soil C, yet the responseto of tropical soil C a warming climate remains poorly understood. Despite predictions of soil C losses, decomposition of soil organic matter (SOM) in tropical soils may be constrained by several factors including microbial nutrient deficiencies. We performed an incubation experiment in conjunction with an in-situ soil warming experiment in a lowland tropical forest on Barro Colorado Island, Panama, to measure microbial response to two key nutrient additions in shallow (0-10cm) and deep (50-100 cm) soils. We compared the response of lowland tropical soils to montane tropical soils, predicting that lowland soils would display the strongest response to phosphorus additions. Soils were treated with either carbon alone (C), nitrogen (CN), phosphorus (CP) or nitrogen and phosphorus combined (CNP). Carbon dioxide (CO2) production was measured by NaOH capture and titrimetric analysis for 10 days. Cumulative CO2 production in montane soils increased significantly with all additions, suggesting these soils are characterized by a general microbial nutrient deficiency. The cumulative amount of C respired in deep soils from the lowland site increased significantly with CP and CNP additions, suggesting that microbial processes in deep lowland tropical soils are phosphorus-limited. These results support the current understanding that lowland tropical forests are growing on highly weathered, phosphorus-deplete soils, and provide novel insight that deep tropical SOM may be stabilized by a lack of biologically-available phosphorus. Further, this data suggests tropical soil C losses under elevated temperature may be limited by a strong microbial phosphorus deficiency.

  1. [Crimean-Congo hemorrhagic fever].

    Science.gov (United States)

    Saijo, Masayuki; Moriikawa, Shigeru; Kurane, Ichiro

    2004-12-01

    Crimean-Congo hemorrhagic fever (CCHF) is an acute infectious disease caused by CCHF virus (CCHFV), a member of the family Bunyaviridae, genus Nairovirus. The case fatality rate of CCHF ranges from 10-40%. Because CCHF is not present in Japan, many Japanese virologists and clinicians are not very familiar with this disease. However, there remains the possibility of an introduction of CCHFV or other hemorrhagic fever viruses into Japan from surrounding endemic areas. Development of diagnostic laboratory capacity for viral hemorrhagic fevers is necessary even in countries without these diseases. At the National Institute of Infectious Diseases, Tokyo, Japan, laboratory-based systems such as recombinant protein-based antibody detection, antigen-capture and pathological examination have been developed. In this review article, epidemiologic and clinical data on CCHF in the Xinjiang Uygur Autonomous Region, compiled through field investigations and diagnostic testing utilizing the aforementioned laboratory systems, are presented. CCHFV infections are closely associated with the environmental conditions, life styles, religion, occupation, and human economic activities. Based on these data, preventive measures for CCHFV infections are also discussed.

  2. Nutrient additions to a tropical rain forest drive substantial soil carbon dioxide losses to the atmosphere

    OpenAIRE

    Cleveland, Cory C.; Townsend, Alan R.

    2006-01-01

    Terrestrial biosphere–atmosphere carbon dioxide (CO2) exchange is dominated by tropical forests, where photosynthetic carbon (C) uptake is thought to be phosphorus (P)-limited. In P-poor tropical forests, P may also limit organic matter decomposition and soil C losses. We conducted a field-fertilization experiment to show that P fertilization stimulates soil respiration in a lowland tropical rain forest in Costa Rica. In the early wet season, when soluble organic matter inputs to soil are hig...

  3. Basal metabolism in tropical birds: Latitude, altitude, and the 'pace of life'

    OpenAIRE

    Londoño, GA; Chappell, MA; Castañeda, MDR; Jankowski, JE; Robinson, SK

    2015-01-01

    © 2014 The Authors. Life history varies across latitudes, with the 'pace of life' being 'slower' in tropical regions. Because life history is coupled to energy metabolism via allocation tradeoffs and links between performance capacity and energy use, low metabolic intensity is expected in tropical animals. Low metabolism has been reported for lowland tropical birds, but it is unclear if this is due to 'slow' life history or to a warm, stable environment. We measured basal metabolic rates (BMR...

  4. Weed communities of rain-fed lowland rice vary with infestation by Rhamphicarpa fistulosa

    Science.gov (United States)

    Houngbédji, Tossimidé; Dessaint, Fabrice; Nicolardot, Bernard; Shykoff, Jacqui A.; Gibot-Leclerc, Stéphanie

    2016-11-01

    The facultative hemiparasitic plant Rhamphicarpa fistulosa (Orobanchaceae) thrives in seasonally wet soils in sub-Saharan Africa, mainly in marginal lowland rice growing environments where weeds are already a major constraint for rice production. Because lowland rice production is increasing in tropical Africa, it is important to ascertain the influence of R. fistulosa on weed plant communities in these rice-growing habitats. We investigated weed plant community richness and composition at four different levels of R. fistulosa infestation across two years of surveys from lowland rice fields in northern Togo (West Africa). Despite a lack of significant differences in community richness among sites with different R. fistulosa infestation levels, there were significant differences in community composition, both when estimated from presence-absence data and from relative abundance data, after controlling statistically for geographic proximity among sites. Rhamphicarpa fistulosa infestation, therefore, may influence the competitive balance between rice and its weeds and shape weed community structure. However, experimental studies are required to elucidate the weed host range of R. fistulosa and the direct and indirect effects of this hemiparasite in rice fields in order to predict its net impact on rice and its weed species.

  5. Widespread decline of Congo rainforest greenness in the past decade.

    Science.gov (United States)

    Zhou, Liming; Tian, Yuhong; Myneni, Ranga B; Ciais, Philippe; Saatchi, Sassan; Liu, Yi Y; Piao, Shilong; Chen, Haishan; Vermote, Eric F; Song, Conghe; Hwang, Taehee

    2014-05-01

    Tropical forests are global epicentres of biodiversity and important modulators of climate change, and are mainly constrained by rainfall patterns. The severe short-term droughts that occurred recently in Amazonia have drawn attention to the vulnerability of tropical forests to climatic disturbances. The central African rainforests, the second-largest on Earth, have experienced a long-term drying trend whose impacts on vegetation dynamics remain mostly unknown because in situ observations are very limited. The Congolese forest, with its drier conditions and higher percentage of semi-evergreen trees, may be more tolerant to short-term rainfall reduction than are wetter tropical forests, but for a long-term drought there may be critical thresholds of water availability below which higher-biomass, closed-canopy forests transition to more open, lower-biomass forests. Here we present observational evidence for a widespread decline in forest greenness over the past decade based on analyses of satellite data (optical, thermal, microwave and gravity) from several independent sensors over the Congo basin. This decline in vegetation greenness, particularly in the northern Congolese forest, is generally consistent with decreases in rainfall, terrestrial water storage, water content in aboveground woody and leaf biomass, and the canopy backscatter anomaly caused by changes in structure and moisture in upper forest layers. It is also consistent with increases in photosynthetically active radiation and land surface temperature. These multiple lines of evidence indicate that this large-scale vegetation browning, or loss of photosynthetic capacity, may be partially attributable to the long-term drying trend. Our results suggest that a continued gradual decline of photosynthetic capacity and moisture content driven by the persistent drying trend could alter the composition and structure of the Congolese forest to favour the spread of drought-tolerant species.

  6. Importance of terrestrial arthropods as subsidies in lowland Neotropical rain forest stream ecosystems

    Science.gov (United States)

    Small, Gaston E.; Torres, Pedro J.; Schwizer, Lauren M.; Duff, John H.; Pringle, Catherine M.

    2013-01-01

    The importance of terrestrial arthropods has been documented in temperate stream ecosystems, but little is known about the magnitude of these inputs in tropical streams. Terrestrial arthropods falling from the canopy of tropical forests may be an important subsidy to tropical stream food webs and could also represent an important flux of nitrogen (N) and phosphorus (P) in nutrient-poor headwater streams. We quantified input rates of terrestrial insects in eight streams draining lowland tropical wet forest in Costa Rica. In two focal headwater streams, we also measured capture efficiency by the fish assemblage and quantified terrestrially derived N- and P-excretion relative to stream nutrient uptake rates. Average input rates of terrestrial insects ranged from 5 to 41 mg dry mass/m2/d, exceeding previous measurements of aquatic invertebrate secondary production in these study streams, and were relatively consistent year-round, in contrast to values reported in temperate streams. Terrestrial insects accounted for half of the diet of the dominant fish species, Priapicthys annectens. Although terrestrially derived fish excretion was found to be a small flux relative to measured nutrient uptake rates in the focal streams, the efficient capture and processing of terrestrial arthropods by fish made these nutrients available to the local stream ecosystem. This aquatic-terrestrial linkage is likely being decoupled by deforestation in many tropical regions, with largely unknown but potentially important ecological consequences.

  7. Synthesis of the Paleoenvironmental changes in the Colombian lowlands

    International Nuclear Information System (INIS)

    Berrio, Juan Carlos

    2002-01-01

    This chapter includes a summary of all cores studied for this thesis, and one important factor to mention about the origin of the lakes at the Colombian lowlands, out of the climatic change, is the riverine influence that have been driven their evolution, some times with stronger dynamic than others, but enough as to be repercussive over the vegetation communities. This sort of dynamics made possible to accumulate different kind of sediments, which can be correlated with the pollen assemblages found in the pollen records. Moreover, multivariate analysis of raw pollen data standardizes the zonation of pollen records (Grimm, 1987), which contribute to get better interpretation from the pollen spectra. The sites of this thesis mainly belongs to the 5 major ecosystems of Colombia as follow: Boquillas in the lower Magdalena valley in the north, savannahs pollen records from the Llanos Orientales in the east, Amazonian pollen records in south and the tropical rain forest in the west and the interandean dry forest in the southwest

  8. Tropical Rainforests.

    Science.gov (United States)

    Nigh, Ronald B.; Nations, James D.

    1980-01-01

    Presented is a summary of scientific knowledge about the rainforest environment, a tropical ecosystem in danger of extermination. Topics include the current state of tropical rainforests, the causes of rainforest destruction, and alternatives of rainforest destruction. (BT)

  9. Bd on the beach: high prevalence of Batrachochytrium dendrobatidis in the lowland forests of Gorgona Island (Colombia, South America).

    Science.gov (United States)

    Flechas, Sandra Victoria; Sarmiento, Carolina; Amézquita, Adolfo

    2012-09-01

    The amphibian chytrid fungus, Batrachochytrium dendrobatidis, Bd, has been implicated in the decimation and extinction of many amphibian populations worldwide, especially at mid and high elevations. Recent studies have demonstrated the presence of the pathogen in the lowlands from Australia and Central America. We extend here its elevational range by demonstrating its presence at the sea level, in the lowland forests of Gorgona Island, off the Pacific coast of Colombia. We conducted two field surveys, separated by four years, and diagnosed Bd by performing polymerase chain reactions on swab samples from the skin of five amphibian species. All species, including the Critically Endangered Atelopus elegans, tested positive for the pathogen, with prevalences between 3.9 % in A. elegans (in 2010) and 52 % in Pristimantis achatinus. Clinical signs of chytridiomycosis were not detected in any species. To our knowledge, this is the first report of B. dendrobatidis in tropical lowlands at sea level, where temperatures may exceed optimal growth temperatures of this pathogen. This finding highlights the need to understand the mechanisms allowing the interaction between frogs and pathogen in lowland ecosystems.

  10. Petroleum possibilities of the James Bay Lowland area: Drilling in the James Bay Lowland

    Energy Technology Data Exchange (ETDEWEB)

    Martison, N W

    1954-12-31

    Interest in the possible occurrence of petroleum and natural gas in the James Bay lowland arises from the presence there of Palaeozoic sedimentary formations resembling those in south-western Ontario. The first part of this report reviews earlier geologic surveys conducted in the lowland and reports results of field work and drill core studies 1946-51. It describes the area`s topography, climate, stratigraphy and palaeontology (Ordovician to Lower Cretaceous, plus Pleistocene and recent glacial deposits), structural geology, and evidence of petroleum. Lists of fossils and correlations are included. The appendices include a list of fossil locations and drill logs. The second part details the drilling programs carried out in the lowland by the Ontario Dept. of Mines, including detailed logs, as well as drilling carried out by some other organisations.

  11. An insight into pre-Columbian raised fields: the case of San Borja, Bolivian lowlands

    Science.gov (United States)

    Rodrigues, Leonor; Lombardo, Umberto; Trauerstein, Mareike; Huber, Perrine; Mohr, Sandra; Veit, Heinz

    2016-07-01

    Pre-Columbian raised field agriculture in the tropical lowlands of South America has received increasing attention and been the focus of heated debates regarding its function, productivity, and role in the development of pre-Columbian societies. Even though raised fields are all associated to permanent or semi-permanent high water levels, they occur in different environmental contexts. Very few field-based studies on raised fields have been carried out in the tropical lowlands and little is known about their use and past management. Based on topographic surveying and mapping, soil physical and chemical analysis and OSL and radiocarbon dating, this paper provides insight into the morphology, functioning and time frame of the use of raised fields in the south-western Llanos de Moxos, Bolivian Amazon. We have studied raised fields of different sizes that were built in an area near the town of San Borja, with a complex fluvial history. The results show that differences in field size and height are the result of an adaptation to a site where soil properties vary significantly on a scale of tens to hundreds of metres. The analysis and dating of the raised fields sediments point towards an extensive and rather brief use of the raised fields, for about 100-200 years at the beginning of the 2nd millennium.

  12. Necromass in forests of Madre de Dios, Peru: a comparison between terra firme and lowland forests

    Directory of Open Access Journals (Sweden)

    Alejandro Araujo-Murakami

    2011-06-01

    Full Text Available Stocks of dead wood or necromass represent an important portion of biomass and nutrients in tropical forests. The objectives of this study were: 1 to evaluate and compare the necromass of “terra firme” and lowlands forests, (2 to study the relationship between necromass, above-ground biomass and wood density, and (3 to estimate the necromass of the department of Madre de Dios, Peru. Stocks of necromass and above-ground biomass were estimated at three different locations using permanent plots and line intercept transects. The average volume of necromass for the three sites was 72.9 m3 ha-1 with an average weight varying between 24.8 and 30.7 Mg ha-1, depending on the estimations of dead wood density used for the calculations. Terra firme forests had significantly higher stocks of necromass than lowland forests. The amount of necromass was 11% of the total above-ground biomass in Madre de Dios forests. The total stock of carbon stored in dead wood for the entire department of Madre de Dios was estimated to be approximately 100 mega tonnes of carbon. This is ten times more than the annual fossil fuel emissions of Peru between 2000 and 2008. The substantial stocks of necromass emphasize the importance of these types of field studies, considering that this component of tropical forest carbon cannot be detected using other methods such as satellite remote sensing.

  13. Erosion rates and landscape evolution of the lowlands of the Upper Paraguay river basin (Brazil) from cosmogenic 10Be

    Science.gov (United States)

    Pupim, Fabiano do Nascimento; Bierman, Paul R.; Assine, Mario Luis; Rood, Dylan H.; Silva, Aguinaldo; Merino, Eder Renato

    2015-04-01

    The importance of Earth's low sloping areas in regard to global erosion and sediment fluxes has been widely and vigorously debated. It is a crucial area of research to elucidate geologically meaningful rates of land-surface change and thus the speed of element cycling on Earth. However, there are large portions of Earth where erosion rates have not been well or extensively measured, for example, the tropical lowlands. The Cuiabana lowlands are an extensive low-altitude and low-relief dissected metamorphic terrain situated in the Upper Paraguay river basin, central-west Brazil. Besides exposures of highly variable dissected metamorphic rocks, flat residual lateritic caps related to a Late Cenozoic planation surface dominate interfluves of the Cuiabana lowlands. The timescale over which the lowlands evolved and the planation surface developed, and the rate at which they have been modified by erosion, are poorly known. Here, we present measurements of in situ produced cosmogenic 10Be in outcropping metamorphic bedrock and clastic-lateritic caps to quantify rates of erosion of the surface and associated landforms in order to better understand the Quaternary landscape evolution of these lowlands. Overall, slow erosion rates (mean 10 m/Ma) suggest a stable tectonic environment in these lowlands. Erosion rates vary widely between different lithologies (range 0.57 to 28.3 m/Ma) consistent with differential erosion driving regional landform evolution. The lowest erosion rates are associated with the low-relief area (irregular plains), where clastic-laterite (mean 0.67 m/Ma) and quartzite (mean 2.6 m/Ma) crop out, whereas the highest erosion rates are associated with dissection of residual hills, dominated by metasandstone (mean 11.6 m/Ma) and phyllite (mean 27.6 m/Ma). These data imply that the Cuiabana lowland is comprised of two dominant landform sets with distinct and different dynamics. Because the planation surface (mostly lowlands) is lowering and losing mass more

  14. Democratic Republic of Congo Jobs Diagnostic

    OpenAIRE

    Aterido, Reyes; Gonzalez, Alvaro; Merotto, Dino; Petracco, Carly; Sanchez-Reaza, Javier

    2018-01-01

    The economy of the Democratic Republic of Congo is not creating sufficient jobs for its young and rapidly growing workforce. Although the Congolese economy has experienced fast growth and poverty has declined, further reducing poverty will require more dynamic job creation and continued reductions in fertility rates. The current youth bulge and potential demographic dividend will open a un...

  15. Crimean-Congo Hemorrhagic Fever, Sudan, 2008

    Centers for Disease Control (CDC) Podcasts

    This podcast describes the emergence of the first human cases of Crimean-Congo Hemorrhagic Fever in Sudan in 2008. CDC epidemiologist Dr. Stuart Nichol discusses how the disease was found in Sudan and how it spread in a hospital there.

  16. Molecular profiling of interspecific lowland rice populations derived ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-03

    Dec 3, 2008 ... Molecular profiling of interspecific lowland rice populations ... Both cluster and principal component analyses revealed two major groups ...... simulations. Theor ... inheritance, chromosomal location, and population dynamics.

  17. Tropical Glaciers

    Science.gov (United States)

    Fountain, Andrew

    The term "tropical glacier" calls to mind balmy nights and palm trees on one hand and cold, blue ice on the other. Certainly author Gabriel Garcia Marqez exploited this contrast in One Hundred Years of Solitude. We know that tropical fish live in warm, Sun-kissed waters and tropical plants provide lush, dense foliage populated by colorful tropical birds. So how do tropical glaciers fit into this scene? Like glaciers everywhere, tropical glaciers form where mass accumulation—usually winter snow—exceeds mass loss, which is generally summer melt. Thus, tropical glaciers exist at high elevations where precipitation can occur as snowfall exceeds melt and sublimation losses, such as the Rwenzori Mountains in east Africa and the Maoke Range of Irian Jaya.

  18. Tropical radioecology

    CERN Document Server

    Baxter, M

    2012-01-01

    Tropical Radioecology is a guide to the wide range of scientific practices and principles of this multidisciplinary field. It brings together past and present studies in the tropical and sub-tropical areas of the planet, highlighting the unique aspects of tropical systems. Until recently, radioecological models for tropical environments have depended upon data derived from temperate environments, despite the differences of these regions in terms of biota and abiotic conditions. Since radioactivity can be used to trace environmental processes in humans and other biota, this book offers examples of studies in which radiotracers have been used to assess biokinetics in tropical biota. Features chapters, co-authored by world experts, that explain the origins, inputs, distribution, behaviour, and consequences of radioactivity in tropical and subtropical systems. Provides comprehensive lists of relevant data and identifies current knowledge gaps to allow for targeted radioecological research in the future. Integrate...

  19. Ecologic Features of Plague Outbreak Areas, Democratic Republic of the Congo, 2004–2014

    Science.gov (United States)

    Shako, Jean-Christophe; Gaudart, Jean; Sudre, Bertrand; Ilunga, Benoit Kebela; Shamamba, Stomy Karhemere Bi; Diatta, Georges; Davoust, Bernard; Tamfum, Jean-Jacques Muyembe; Piarroux, Renaud; Piarroux, Martine

    2018-01-01

    During 2004–2014, the Democratic Republic of the Congo (DRC) declared 54% of plague cases worldwide. Using national data, we characterized the epidemiology of human plague in DRC for this period. All 4,630 suspected human plague cases and 349 deaths recorded in DRC came from Orientale Province. Pneumonic plague cases (8.8% of total) occurred during 2 major outbreaks in mining camps in the equatorial forest, and some limited outbreaks occurred in the Ituri highlands. Epidemics originated in 5 health zones clustered in Ituri, where sporadic bubonic cases were recorded throughout every year. Classification and regression tree characterized this cluster by the dominance of ecosystem 40 (mountain tropical climate). In conclusion, a small, stable, endemic focus of plague in the highlands of the Ituri tropical region persisted, acting as a source of outbreaks in DRC. PMID:29350136

  20. Western lowland gorilla diet and resource availability: new evidence, cross-site comparisons, and reflections on indirect sampling methods.

    Science.gov (United States)

    Doran, Diane M; McNeilage, Alastair; Greer, David; Bocian, Carolyn; Mehlman, Patrick; Shah, Natasha

    2002-11-01

    We describe the resource availability and diet of western lowland gorillas (Gorilla gorilla gorilla) from a new study site in the Central African Republic and Republic of Congo based on 3 years of study. The results, based on 715 fecal samples and 617 days of feeding trails, were similar to those reported from three other sites, in spite of differences in herb and fruit availability. Staple foods (consumed year-round) included high-quality herbs (Haumania), swamp herbs (when present), and a minimal diversity of fruit. A variety of fruits (average of 3.5 species per day and 10 per month) were selectively consumed; gorillas ignored some common fruits and incorporated rare fruits to a degree higher than predicted based on availability. During periods of fruit abundance, fruit constituted most of the diet. When succulent fruits were unavailable, gorillas used low-quality herbs (i.e., low-protein), bark, and more fibrous fruits as fallback foods. Fibrous fruit species, such as Duboscia macrocarpa and Klainedoxa gabonensis, were particularly important to gorillas at Mondika and other sites as fallbacks. The densities of these two species are similar across sites for which data are available, in spite of major differences in forest structure, suggesting they may be key species in determining gorilla density. No sex difference in diet was detected. Such little variation in western lowland gorilla diet across sites and between sexes was unexpected and may partly reflect limitations of indirect sampling. Copyright 2002 Wiley-Liss, Inc.

  1. Quelles sont les causes de la déforestation dans le bassin du Congo ? Synthèse bibliographique et études de cas

    Directory of Open Access Journals (Sweden)

    Gillet, P.

    2016-01-01

    Full Text Available Drivers of deforestation in the Congo basin tropical forest. A review. Description of the subject. The forests of the Congo Basin are among the best preserved areas on Earth. Nevertheless, the factors causing deforestation around the world are also present in this subregion. This document presents a literature review of the direct causes and underlying factors of deforestation in the tropical areas and highlights the drivers of deforestation in the Congo Basin and particularly in Cameroon and Gabon. Literature. Direct causes of deforestation, defined as having a direct cause-and-consequence connection with the destruction of forest cover, are underpinned by economic factors, technological developments, pro-deforestation policy measures and demographic pressures. These factors interact in different ways in the various tropical regions worldwide, which explains the differences and similarities of regional deforestation dynamics. Beside the expansion of infrastructure, the development of mining and timber extraction, agriculture is the main direct cause of deforestation in the Congo Basin. In Cameroon, the current deforestation is primarily driven by agriculture. The State emergency plan includes the development of infrastructure, the modernization of production, equipment and mining. The lack of strategy for rapidly changing demographics might be the most important underlying cause of deforestation. In Gabon, although the deforestation rate is low, agriculture and the opening of roads are main drivers. The emergency plan includes modernization of infrastructure and the development of agro-industrial agriculture. Conclusions. A mutation of socio-ecosystems is expected in different parts of the Congo Basin. Future research should now turn to the analysis of socio-ecosystems representative of the various stages of the forest transition and identify drivers of change at different scales.

  2. Ocular pentastomiasis in the Democratic Republic of the Congo.

    Directory of Open Access Journals (Sweden)

    Mihály Sulyok

    2014-07-01

    Full Text Available Ocular pentastomiasis is a rare infection caused by the larval stage of pentastomids, an unusual group of crustacean-related parasites. Zoonotic pentastomids have a distinct geographical distribution and utilize reptiles or canids as final hosts. Recently, an increasing number of human abdominal infections have been reported in Africa, where pentastomiasis is an emerging, though severely neglected, tropical disease. Here we describe four ocular infections caused by pentastomids from the Democratic Republic of the Congo. Two cases underwent surgery and an Armillifer grandis infection was detected by morphological and molecular approaches. Thus far, 15 other cases of ocular pentastomiasis have been reported worldwide. Twelve cases were caused by Armillifer sp., recorded almost exclusively in Africa, where such infections occur as a consequence of hunting and consuming snakes, their final hosts. Seven further cases were caused by Linguatula serrata, a cosmopolitan pentastomid whose final hosts are usually canids. Intraocular infections caused permanent visual damage in 69% and a total loss of vision in 31% of reported cases. In contrast, ocular adnexal cases had a benign clinical course. Further research is required to estimate the burden, therapeutic options and pathogenesis of this neglected disease.

  3. Population history, phylogeography, and conservation genetics of the last Neotropical mega-herbivore, the lowland tapir (Tapirus terrestris

    Directory of Open Access Journals (Sweden)

    de Thoisy Benoit

    2010-09-01

    Full Text Available Abstract Background Understanding the forces that shaped Neotropical diversity is central issue to explain tropical biodiversity and inform conservation action; yet few studies have examined large, widespread species. Lowland tapir (Tapirus terrrestris, Perissodactyla, Tapiridae is the largest Neotropical herbivore whose ancestors arrived in South America during the Great American Biotic Interchange. A Pleistocene diversification is inferred for the genus Tapirus from the fossil record, but only two species survived the Pleistocene megafauna extinction. Here, we investigate the history of lowland tapir as revealed by variation at the mitochondrial gene Cytochrome b, compare it to the fossil data, and explore mechanisms that could have shaped the observed structure of current populations. Results Separate methodological approaches found mutually exclusive divergence times for lowland tapir, either in the late or in the early Pleistocene, although a late Pleistocene divergence is more in tune with the fossil record. Bayesian analysis favored mountain tapir (T. pinchaque paraphyly in relation to lowland tapir over reciprocal monophyly, corroborating the inferences from the fossil data these species are sister taxa. A coalescent-based analysis rejected a null hypothesis of allopatric divergence, suggesting a complex history. Based on the geographic distribution of haplotypes we propose (i a central role for western Amazonia in tapir diversification, with a key role of the ecological gradient along the transition between Andean subcloud forests and Amazon lowland forest, and (ii that the Amazon river acted as an barrier to gene flow. Finally, the branching patterns and estimates based on nucleotide diversity indicate a population expansion after the Last Glacial Maximum. Conclusions This study is the first examining lowland tapir phylogeography. Climatic events at the end of the Pleistocene, parapatric speciation, divergence along the Andean foothill

  4. Population history, phylogeography, and conservation genetics of the last Neotropical mega-herbivore, the lowland tapir (Tapirus terrestris).

    Science.gov (United States)

    de Thoisy, Benoit; da Silva, Anders Gonçalves; Ruiz-García, Manuel; Tapia, Andrés; Ramirez, Oswaldo; Arana, Margarita; Quse, Viviana; Paz-y-Miño, César; Tobler, Mathias; Pedraza, Carlos; Lavergne, Anne

    2010-09-14

    Understanding the forces that shaped Neotropical diversity is central issue to explain tropical biodiversity and inform conservation action; yet few studies have examined large, widespread species. Lowland tapir (Tapirus terrrestris, Perissodactyla, Tapiridae) is the largest Neotropical herbivore whose ancestors arrived in South America during the Great American Biotic Interchange. A Pleistocene diversification is inferred for the genus Tapirus from the fossil record, but only two species survived the Pleistocene megafauna extinction. Here, we investigate the history of lowland tapir as revealed by variation at the mitochondrial gene Cytochrome b, compare it to the fossil data, and explore mechanisms that could have shaped the observed structure of current populations. Separate methodological approaches found mutually exclusive divergence times for lowland tapir, either in the late or in the early Pleistocene, although a late Pleistocene divergence is more in tune with the fossil record. Bayesian analysis favored mountain tapir (T. pinchaque) paraphyly in relation to lowland tapir over reciprocal monophyly, corroborating the inferences from the fossil data these species are sister taxa. A coalescent-based analysis rejected a null hypothesis of allopatric divergence, suggesting a complex history. Based on the geographic distribution of haplotypes we propose (i) a central role for western Amazonia in tapir diversification, with a key role of the ecological gradient along the transition between Andean subcloud forests and Amazon lowland forest, and (ii) that the Amazon river acted as an barrier to gene flow. Finally, the branching patterns and estimates based on nucleotide diversity indicate a population expansion after the Last Glacial Maximum. This study is the first examining lowland tapir phylogeography. Climatic events at the end of the Pleistocene, parapatric speciation, divergence along the Andean foothill, and role of the Amazon river, have similarly shaped

  5. La violencia sexual en Kivu Sur, Congo

    OpenAIRE

    Rodríguez, Claudia

    2007-01-01

    Abordar la violencia sexual y por motivos de género en la República Democrática del Congo (RDC) requerirá más recursos y coordinación. Un sistema judicial débil o inexistente disuade a las sobrevivientes de denunciar a sus agresores. El número de agresiones sigue aumentando y los perpetradores quedan impunes.

  6. Crimean-Congo Hemorrhagic Fever, Sudan, 2008

    Centers for Disease Control (CDC) Podcasts

    2010-04-15

    This podcast describes the emergence of the first human cases of Crimean-Congo Hemorrhagic Fever in Sudan in 2008. CDC epidemiologist Dr. Stuart Nichol discusses how the disease was found in Sudan and how it spread in a hospital there.  Created: 4/15/2010 by National Center for Emerging and Zoonotic Infections (proposed).   Date Released: 4/15/2010.

  7. Age, extent and carbon storage of the central Congo Basin peatland complex.

    Science.gov (United States)

    Dargie, Greta C; Lewis, Simon L; Lawson, Ian T; Mitchard, Edward T A; Page, Susan E; Bocko, Yannick E; Ifo, Suspense A

    2017-02-02

    Peatlands are carbon-rich ecosystems that cover just three per cent of Earth's land surface, but store one-third of soil carbon. Peat soils are formed by the build-up of partially decomposed organic matter under waterlogged anoxic conditions. Most peat is found in cool climatic regions where unimpeded decomposition is slower, but deposits are also found under some tropical swamp forests. Here we present field measurements from one of the world's most extensive regions of swamp forest, the Cuvette Centrale depression in the central Congo Basin. We find extensive peat deposits beneath the swamp forest vegetation (peat defined as material with an organic matter content of at least 65 per cent to a depth of at least 0.3 metres). Radiocarbon dates indicate that peat began accumulating from about 10,600 years ago, coincident with the onset of more humid conditions in central Africa at the beginning of the Holocene. The peatlands occupy large interfluvial basins, and seem to be largely rain-fed and ombrotrophic-like (of low nutrient status) systems. Although the peat layer is relatively shallow (with a maximum depth of 5.9 metres and a median depth of 2.0 metres), by combining in situ and remotely sensed data, we estimate the area of peat to be approximately 145,500 square kilometres (95 per cent confidence interval of 131,900-156,400 square kilometres), making the Cuvette Centrale the most extensive peatland complex in the tropics. This area is more than five times the maximum possible area reported for the Congo Basin in a recent synthesis of pantropical peat extent. We estimate that the peatlands store approximately 30.6 petagrams (30.6 × 10 15  grams) of carbon belowground (95 per cent confidence interval of 6.3-46.8 petagrams of carbon)-a quantity that is similar to the above-ground carbon stocks of the tropical forests of the entire Congo Basin. Our result for the Cuvette Centrale increases the best estimate of global tropical peatland carbon stocks by

  8. Mineral content as a basis for food selection by western lowland gorillas in a forest clearing.

    Science.gov (United States)

    Magliocca, Florence; Gautier-Hion, Annie

    2002-06-01

    The forests in northwest Republic of Congo contain a number of herbaceous swamp clearings that provide foraging sites for lowland gorillas (G.g. gorilla). A 10-month study at the Maya Nord clearing (Parc National d'Odzala) showed that feeding activities occupied 72% of the time visiting gorillas spent on the clearing. They fed on four plant species: Enydra fluctuans (Asteraceae), Cyperus sp., Pycreus mundtii, and Rhynchospora corymbosa (Cyperaceae) among the 45 species recorded on the clearing. These clearing food species have higher mineral contents (especially Na and Ca) than the dominant Marantaceae species (Haumania liebrechtsiana) that constituted a staple food plant for gorillas in this forest. They also have higher potassium contents and contain less lignin than non-eaten clearing items/species. Finally, the most actively searched for clearing food (Enydra fluctuans) was characterized by the highest amount of Na and Ca. These results suggest that the mineral content (especially in Na, Ca, and/or K) could determine the feeding selectivity of gorillas at the clearing. They also tend to confirm that the amount of fiber plays a deterrent role in food selectivity, as has been found by many authors. The high density of gorillas in that region could result from the combination of the large areas of Marantaceae forests that provide abundant though monotonous food, and the number of clearings that provide sufficient mineral supplies. Clearings should thus be considered as key habitats for the conservation of gorillas. Copyright 2002 Wiley-Liss, Inc.

  9. A Stochastic Water Balance Framework for Lowland Watersheds

    Science.gov (United States)

    Thompson, Sally; MacVean, Lissa; Sivapalan, Murugesu

    2017-11-01

    The water balance dynamics in lowland watersheds are influenced not only by local hydroclimatic controls on energy and water availability, but also by imports of water from the upstream watershed. These imports result in a stochastic extent of inundation in lowland watersheds that is determined by the local flood regime, watershed topography, and the rate of loss processes such as drainage and evaporation. Thus, lowland watershed water balances depend on two stochastic processes—rainfall and local inundation dynamics. Lowlands are high productivity environments that are disproportionately associated with urbanization, high productivity agriculture, biodiversity, and flood risk. Consequently, they are being rapidly altered by human development—generally with clear economic and social motivation—but also with significant trade-offs in ecosystem services provision, directly related to changes in the components and variability of the lowland water balance. We present a stochastic framework to assess the lowland water balance and its sensitivity to two common human interventions—replacement of native vegetation with alternative land uses, and construction of local flood protection levees. By providing analytical solutions for the mean and PDF of the water balance components, the proposed framework provides a mechanism to connect human interventions to hydrologic outcomes, and, in conjunction with ecosystem service production estimates, to evaluate trade-offs associated with lowland watershed development.

  10. Re-Meandering of Lowland Streams

    DEFF Research Database (Denmark)

    Pedersen, Morten Lauge; Kristensen, Klaus Kevin; Friberg, Nikolai

    2014-01-01

    We evaluated the restoration of physical habitats and its influence on macroinvertebrate community structure in 18 Danish lowland streams comprising six restored streams, six streams with little physical alteration and six channelized streams. We hypothesized that physical habitats...... and macroinvertebrate communities of restored streams would resemble those of natural streams, while those of the channelized streams would differ from both restored and near-natural streams. Physical habitats were surveyed for substrate composition, depth, width and current velocity. Macroinvertebrates were sampled...... along 100 m reaches in each stream, in edge habitats and in riffle/run habitats located in the center of the stream. Restoration significantly altered the physical conditions and affected the interactions between stream habitat heterogeneity and macroinvertebrate diversity. The substrate in the restored...

  11. Internet Backbone in the Democratic Republic of Congo : Feasibility ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Internet Backbone in the Democratic Republic of Congo : Feasibility Study and Advocacy. During 7-10 February 2005, representatives of five francophone African countries (Cameroon, Morocco, Niger, Sénégal, and the Democratic Republic of Congo - DRC) met to consider ways and means of galvanizing the appropriation ...

  12. Flood occurrence mapping of the middle Mahakam lowland area using satellite radar

    Directory of Open Access Journals (Sweden)

    H. Hidayat

    2012-07-01

    Full Text Available Floodplain lakes and peatlands in the middle Mahakam lowland area are considered as ecologically important wetland in East Kalimantan, Indonesia. However, due to a lack of data, the hydrological functioning of the region is still poorly understood. Among remote sensing techniques that can increase data availability, radar is well-suitable for the identification, mapping, and measurement of tropical wetlands, for its cloud unimpeded sensing and night and day operation. Here we aim to extract flood extent and flood occurrence information from a series of radar images of the middle Mahakam lowland area. We explore the use of Phased Array L-band Synthetic Aperture Radar (PALSAR imagery for observing flood inundation dynamics by incorporating field water level measurements. Water level measurements were carried out along the river, in lakes and in peatlands, using pressure transducers. For validation of the open water flood occurrence map, bathymetry measurements were carried out in the main lakes. A series of PALSAR images covering the middle and lower Mahakam area in the years 2007 through 2010 were collected. A fully inundated region can be easily recognized on radar images from a dark signature. Open water flood occurrence was mapped using a threshold value taken from radar backscatter of the permanently inundated river and lakes areas. Radar backscatter intensity analysis of the vegetated floodplain area revealed consistently high backscatter values, indicating flood inundation under forest canopy. We used those values as the threshold for flood occurrence mapping in the vegetated area.

  13. Aboveground tree growth varies with belowground carbon allocation in a tropical rainforest environment

    Science.gov (United States)

    J.W. Raich; D.A. Clark; L. Schwendenmann; Tana Wood

    2014-01-01

    Young secondary forests and plantations in the moist tropics often have rapid rates of biomass accumulation and thus sequester large amounts of carbon. Here, we compare results from mature forest and nearby 15–20 year old tree plantations in lowland Costa Rica to evaluate differences in allocation of carbon to aboveground production and root systems. We found that the...

  14. Geographic, environmental and biotic sources of variation in the nutrient relations of tropical montane forests

    Science.gov (United States)

    James W. Dalling; Katherine Heineman; Grizelle Gonzalez; Rebecca Ostertag

    2016-01-01

    Tropicalmontane forests (TMF) are associated with a widely observed suite of characteristics encompassing forest structure, plant traits and biogeochemistry.With respect to nutrient relations, montane forests are characterized by slow decomposition of organic matter, high investment in below-ground biomass and poor litter quality, relative to tropical lowland forests....

  15. The linkages between photosynthesis, productivity, growth and biomass in lowland Amazonian forests.

    Science.gov (United States)

    Malhi, Yadvinder; Doughty, Christopher E; Goldsmith, Gregory R; Metcalfe, Daniel B; Girardin, Cécile A J; Marthews, Toby R; Del Aguila-Pasquel, Jhon; Aragão, Luiz E O C; Araujo-Murakami, Alejandro; Brando, Paulo; da Costa, Antonio C L; Silva-Espejo, Javier E; Farfán Amézquita, Filio; Galbraith, David R; Quesada, Carlos A; Rocha, Wanderley; Salinas-Revilla, Norma; Silvério, Divino; Meir, Patrick; Phillips, Oliver L

    2015-06-01

    Understanding the relationship between photosynthesis, net primary productivity and growth in forest ecosystems is key to understanding how these ecosystems will respond to global anthropogenic change, yet the linkages among these components are rarely explored in detail. We provide the first comprehensive description of the productivity, respiration and carbon allocation of contrasting lowland Amazonian forests spanning gradients in seasonal water deficit and soil fertility. Using the largest data set assembled to date, ten sites in three countries all studied with a standardized methodology, we find that (i) gross primary productivity (GPP) has a simple relationship with seasonal water deficit, but that (ii) site-to-site variations in GPP have little power in explaining site-to-site spatial variations in net primary productivity (NPP) or growth because of concomitant changes in carbon use efficiency (CUE), and conversely, the woody growth rate of a tropical forest is a very poor proxy for its productivity. Moreover, (iii) spatial patterns of biomass are much more driven by patterns of residence times (i.e. tree mortality rates) than by spatial variation in productivity or tree growth. Current theory and models of tropical forest carbon cycling under projected scenarios of global atmospheric change can benefit from advancing beyond a focus on GPP. By improving our understanding of poorly understood processes such as CUE, NPP allocation and biomass turnover times, we can provide more complete and mechanistic approaches to linking climate and tropical forest carbon cycling. © 2015 John Wiley & Sons Ltd.

  16. Habitats of 0+ fry in an English lowland river

    Czech Academy of Sciences Publication Activity Database

    Duncan, A.; Kubečka, Jan; Kett, S.; Hanna, N.; Skeldon, J.

    2001-01-01

    Roč. 12, 2-4 (2001), s. 153-171 ISSN 0945-3784 Institutional research plan: CEZ:AV0Z6017912 Keywords : 0+ fish communities * lowland river * connected backwater Subject RIV: DA - Hydrology ; Limnology

  17. Yield constraint analysis of rainfed lowland rice in Souteast Asia

    NARCIS (Netherlands)

    Boling, A.A.

    2007-01-01

    Keywords: Fertilizer application, field hydrology, plant nutrient uptake, toposequence, weed control, yield loss. Rainfed lowland rice yields are low and unstable due to uncertain water supply, low soil fertility, and pest infestation. To design management interventions aimed at increasing

  18. Drought, agricultural adaptation, and sociopolitical collapse in the Maya Lowlands

    Science.gov (United States)

    Douglas, Peter M. J.; Pagani, Mark; Canuto, Marcello A.; Brenner, Mark; Hodell, David A.; Eglinton, Timothy I.; Curtis, Jason H.

    2015-01-01

    Paleoclimate records indicate a series of severe droughts was associated with societal collapse of the Classic Maya during the Terminal Classic period (∼800–950 C.E.). Evidence for drought largely derives from the drier, less populated northern Maya Lowlands but does not explain more pronounced and earlier societal disruption in the relatively humid southern Maya Lowlands. Here we apply hydrogen and carbon isotope compositions of plant wax lipids in two lake sediment cores to assess changes in water availability and land use in both the northern and southern Maya lowlands. We show that relatively more intense drying occurred in the southern lowlands than in the northern lowlands during the Terminal Classic period, consistent with earlier and more persistent societal decline in the south. Our results also indicate a period of substantial drying in the southern Maya Lowlands from ∼200 C.E. to 500 C.E., during the Terminal Preclassic and Early Classic periods. Plant wax carbon isotope records indicate a decline in C4 plants in both lake catchments during the Early Classic period, interpreted to reflect a shift from extensive agriculture to intensive, water-conservative maize cultivation that was motivated by a drying climate. Our results imply that agricultural adaptations developed in response to earlier droughts were initially successful, but failed under the more severe droughts of the Terminal Classic period. PMID:25902508

  19. Drought, agricultural adaptation, and sociopolitical collapse in the Maya Lowlands.

    Science.gov (United States)

    Douglas, Peter M J; Pagani, Mark; Canuto, Marcello A; Brenner, Mark; Hodell, David A; Eglinton, Timothy I; Curtis, Jason H

    2015-05-05

    Paleoclimate records indicate a series of severe droughts was associated with societal collapse of the Classic Maya during the Terminal Classic period (∼800-950 C.E.). Evidence for drought largely derives from the drier, less populated northern Maya Lowlands but does not explain more pronounced and earlier societal disruption in the relatively humid southern Maya Lowlands. Here we apply hydrogen and carbon isotope compositions of plant wax lipids in two lake sediment cores to assess changes in water availability and land use in both the northern and southern Maya lowlands. We show that relatively more intense drying occurred in the southern lowlands than in the northern lowlands during the Terminal Classic period, consistent with earlier and more persistent societal decline in the south. Our results also indicate a period of substantial drying in the southern Maya Lowlands from ∼200 C.E. to 500 C.E., during the Terminal Preclassic and Early Classic periods. Plant wax carbon isotope records indicate a decline in C4 plants in both lake catchments during the Early Classic period, interpreted to reflect a shift from extensive agriculture to intensive, water-conservative maize cultivation that was motivated by a drying climate. Our results imply that agricultural adaptations developed in response to earlier droughts were initially successful, but failed under the more severe droughts of the Terminal Classic period.

  20. Forest Elephant Crisis in the Congo Basin

    Science.gov (United States)

    Blake, Stephen; Strindberg, Samantha; Boudjan, Patrick; Makombo, Calixte; Bila-Isia, Inogwabini; Ilambu, Omari; Grossmann, Falk; Bene-Bene, Lambert; de Semboli, Bruno; Mbenzo, Valentin; S'hwa, Dino; Bayogo, Rosine; Williamson, Liz; Fay, Mike; Hart, John; Maisels, Fiona

    2007-01-01

    Debate over repealing the ivory trade ban dominates conferences of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Resolving this controversy requires accurate estimates of elephant population trends and rates of illegal killing. Most African savannah elephant populations are well known; however, the status of forest elephants, perhaps a distinct species, in the vast Congo Basin is unclear. We assessed population status and incidence of poaching from line-transect and reconnaissance surveys conducted on foot in sites throughout the Congo Basin. Results indicate that the abundance and range of forest elephants are threatened from poaching that is most intense close to roads. The probability of elephant presence increased with distance to roads, whereas that of human signs declined. At all distances from roads, the probability of elephant occurrence was always higher inside, compared to outside, protected areas, whereas that of humans was always lower. Inside protected areas, forest elephant density was correlated with the size of remote forest core, but not with size of protected area. Forest elephants must be prioritised in elephant management planning at the continental scale. PMID:17407383

  1. Response Of Lowland Rice To Soil Compaction

    International Nuclear Information System (INIS)

    Idawati; Haryanto

    2000-01-01

    Soil compaction, as a new tillage practice for paddy soil, is to substitute pudding in order to reduce land preparation cost. To study response of lowland rice to soil compaction, a pot experiment has been conducted which took place in the greenhouse of P3TIR-BATAN. Soil for experiment was taken from pusakanegara. Two factors (degree of soil compaction and rice variety) were combined. Degree of compaction was split into 3 levels (DI = normal; D215% more compact than normal; 30 % more compact than normal), and rice variety into 2 levels (IR64 and Atomita IV). KH 2 32 PO 4 solution was injected into the soil surrounding rice clump to test the root activity at blooming stage of rice plant. Data resulted from this experiment is presented together with additional data from some other experiments of fertilization in the research s erie to study soil compaction. Some information's from experiment results are as following. Both rice varieties tested gave the same response to soil compaction. Root activity, according to data of 32 P absorbed by plant, was not harmed by soil compaction at the degree tested in the experiment. This prediction is supported by the growth by rice observed at generative growth stage, in pot experiment as well as in field experiment, which showed that soil compaction tested did not decrease rice yield but in opposite in tended to increase the yield. In practising soil compaction in land preparation, fertilizers should be applied by deep placement to have higher increasing is rice yield

  2. The conditions for uranium concentration in the phosphates of Tchivoula, Congo

    International Nuclear Information System (INIS)

    Giresse, P.; N'Landou, J. de Dieu; Wiber, M.

    1986-01-01

    The processes of deposition of marine phosphates in the Maastrichtian seas of the Congo do not appear capable alone of having produced the significant concentrations of uranium found. Diagenetic phenomena resulted in a mobilisation and a secondary concentration of uranium in the interior of recrystallized apatites. This secondary uranium may have been derived from the residual organic matrix in the deposit. Towards the top of the beds, hydrolysis of the apatites and authigenesis of crandallite, barrandite and ferruginous variscite led to uranium concentrations which are characteristic of alteration in a tropical climate. In contrast, wavellite, the final product of supergene alteration does not retain uranium. In the case of the Tchivoula deposits, the overlying Paleocene beds may have been the source of the uraniferous solutions' downslope movement which favored concentration in the underlying sediments. (orig.)

  3. The biogeochemistry of carbon across a gradient of streams and rivers within the Congo Basin

    Science.gov (United States)

    Mann, P. J.; Spencer, R. G. M.; Dinga, B. J.; Poulsen, J. R.; Hernes, P. J.; Fiske, G.; Salter, M. E.; Wang, Z. A.; Hoering, K. A.; Six, J.; Holmes, R. M.

    2014-04-01

    Dissolved organic carbon (DOC) and inorganic carbon (DIC, pCO2), lignin biomarkers, and theoptical properties of dissolved organic matter (DOM) were measured in a gradient of streams and rivers within the Congo Basin, with the aim of examining how vegetation cover and hydrology influences the composition and concentration of fluvial carbon (C). Three sampling campaigns (February 2010, November 2010, and August 2011) spanning 56 sites are compared by subbasin watershed land cover type (savannah, tropical forest, and swamp) and hydrologic regime (high, intermediate, and low). Land cover properties predominately controlled the amount and quality of DOC, chromophoric DOM (CDOM) and lignin phenol concentrations (∑8) exported in streams and rivers throughout the Congo Basin. Higher DIC concentrations and changing DOM composition (lower molecular weight, less aromatic C) during periods of low hydrologic flow indicated shifting rapid overland supply pathways in wet conditions to deeper groundwater inputs during drier periods. Lower DOC concentrations in forest and swamp subbasins were apparent with increasing catchment area, indicating enhanced DOC loss with extended water residence time. Surface water pCO2 in savannah and tropical forest catchments ranged between 2,600 and 11,922 µatm, with swamp regions exhibiting extremely high pCO2 (10,598-15,802 µatm), highlighting their potential as significant pathways for water-air efflux. Our data suggest that the quantity and quality of DOM exported to streams and rivers are largely driven by terrestrial ecosystem structure and that anthropogenic land use or climate change may impact fluvial C composition and reactivity, with ramifications for regional C budgets and future climate scenarios.

  4. Basal metabolism in tropical birds: latitude, altitude, and the ‘pace of life’

    OpenAIRE

    Londoño, Gustavo Adolfo

    2015-01-01

    Life history varies across latitudes, with the ‘pace of life’ being ‘slower’ in tropical regions. Because life history is coupled to energy metabolism via allocation tradeoffs and links between performance capacity and energy use, low metabolic intensity is expected in tropical animals. Low metabolism has been reported for lowland tropical birds, but it is unclear if this is due to ‘slow’ life history or to a warm, stable environment. We measured basal metabolic rates (BMR) of 253 bird spe...

  5. Accounting for violence in Eastern Congo: Young people's ...

    African Journals Online (AJOL)

    In these accounts, the voices of young people have been largely absent. Although ... in eastern Congo from September to December 2009 as part of the author's doctoral ..... More rarely, young Congolese recognised the contribution made by ...

  6. Decolorisation of Congo Red by Aeromonas hydrophila Under Microaerophilic Conditions

    International Nuclear Information System (INIS)

    El Gizawy, S.; Refae, R.A.; Abd El Kareem, H.; Gomaa, O.M.; Hamed, H.

    2009-01-01

    Among 22 local bacterial isolates, Aeromonas hydrophila isolated from Bolti fish showed a remarkable ability to decolorize congo red under microaerophilic conditions (98.8% in 48 hrs) without prior adaptation. The bacterium had the ability to grow and decolorized high concentrations of congo red which varied from 50 to 1000 mg/l , the decolorisation was irrelevant to bacterial growth. The strain was capable of decolorizing congo red under a wide range of temperatures (20-40 degree C), ph (3-8), NaCl (0-200 mg/l) and also had the ability to decolorized mono, di and poly azo dyes. This bacterium is notable in its ability to decolorized the diazo congo red under extreme conditions of temperature, ph, salinity and high dye concentrations which makes it suitable for decolorisation under extreme industrial conditions

  7. The Congo crisis, the United Nations, and Zimbabwean nationalism ...

    African Journals Online (AJOL)

    United Nations moved swiftly in response to Lumumba's immediate request for assistance .... of apathy towards the white man in Africa and a strong desire to rid .... such actions would legitimatise the intervention of the Congo government in.

  8. Complex conflict in the Democratic Republic of the Congo: Good ...

    African Journals Online (AJOL)

    ... identifi ed business ethics as a way to mitigate the destructive commercial practices that ... Ethical business initiatives have peacebuilding potential; however, the ... of the Congo (DRC) and its surrounding areas by purchasing minerals that fi ...

  9. DENTAL LESIONS IN THE LOWLAND TAPIR (TAPIRUS TERRESTRIS).

    Science.gov (United States)

    Tjørnelund, Karen B; Jonsson, Lena M; Kortegaard, Hanne; Arnbjerg, Jens; Nielsen, Søren S; Bertelsen, Mads F

    2015-06-01

    Dental ailments, mandibular swelling, and dentoalveolar abscesses are common in tapirs, but knowledge about prevalence or etiology of these lesions in the Tapiridae family in general, and in lowland tapirs (Tapirus terrestris) in particular, is scarce. A recent study identified resorptive lesions of unknown etiology as a common problem in the Malayan tapir (Tapirus indicus). In order to investigate the type and prevalence of dental lesions occurring in lowland tapirs, and to compare these with findings with the Malayan tapir, skulls and teeth from 46 deceased lowland tapirs were visually and radiographically examined. The specimens were divided into subpopulations according to age (juveniles, young adults, adults) and origin (free-range or captive). Dental lesions were identified in 24% (11/46) of the study population. The most common pathologic findings were complicated dental fractures with associated periapical reaction (15%) and periapical reactions of various degrees without associated detectable dental pathology (13%). All these lesions likely originated from dental trauma. As in Malayan tapirs, juveniles had significantly fewer lesions than adults. This study shows that dental lesions present frequent problems for lowland tapirs, occurring both in captive and in free-ranging individuals, and indicates that increasing age should be considered a risk factor for the development of these lesions. Notably, the predominant dental problems in lowland tapirs and Malayan tapirs are not the same.

  10. Tropical Deforestation.

    Science.gov (United States)

    Raven, Peter H.

    1988-01-01

    Outlines the deforestation problem and some efforts for solving the problem. Considers the impact of population growth, poverty, and ignorance. Includes a discussion of the current rapid decline in tropical forests, the consequences of destruction, and an outlook for the future. (YP)

  11. Effects of Increased Nitrogen Availability on C and N Cycles in Tropical Forests: A Meta-Analysis

    Science.gov (United States)

    2015-01-01

    Atmospheric N deposition is predicted to increase four times over its current status in tropical forests by 2030. Our ability to understand the effects of N enrichment on C and N cycles is being challenged by the large heterogeneity of the tropical forest biome. The specific response will depend on the forest’s nutrient status; however, few studies of N addition appear to incorporate the nutrient status in tropical forests, possibly due to difficulties in explaining how this status is maintained. We used a meta-analysis to explore the consequences of the N enrichment on C and N cycles in tropical montane and lowland forests. We tracked changes in aboveground and belowground plant C and N and in mineral soil in response to N addition. We found an increasing trend of plant biomass in montane forests, but not in lowland forests, as well as a greater increase in NO emission in montane forest compared with lowland forest. The N2O and NO emission increase in both forest; however, the N2O increase in lowland forest was significantly even at first time N addition. The NO emission increase showed be greater at first term compared with long term N addition. Moreover, the increase in total soil N, ammonium, microbial N, and dissolved N concentration under N enrichment indicates a rich N status of lowland forests. The available evidence of N addition experiments shows that the lowland forest is richer in N than montane forests. Finally, the greater increase in N leaching and N gas emission highlights the importance of study the N deposition effect on the global climate change. PMID:26633681

  12. Mycoremediation of congo red dye by filamentous fungi.

    Science.gov (United States)

    Bhattacharya, Sourav; Das, Arijit; G, Mangai; K, Vignesh; J, Sangeetha

    2011-10-01

    Azo, anthroquinone and triphenylmethane dyes are the major classes of synthetic colourants, which are difficult to degrade and have received considerable attention. Congo red, a diazo dye, is considered as a xenobiotic compound, and is recalcitrant to biodegradative processes. Nevertheless, during the last few years it has been demonstrated that several fungi, under certain environmental conditions, are able to transfer azo dyes to non toxic products using laccases. The aim of this work was to study the factors influencing mycoremediation of Congo red. Several basidiomycetes and deuteromycetes species were tested for the decolourisation of Congo red (0.05 g/l) in a semi synthetic broth at static and shaking conditions. Poor decolourisation was observed when the dye acted as the sole source of nitrogen, whereas semi synthetic broth supplemented with fertilizer resulted in better decolourisation. Decolourisation of Congo red was checked in the presence of salts of heavy metals such as mercuric chloride, lead acetate and zinc sulphate. Decolourisation parameters such as temperature, pH, and rpm were optimized and the decolourisation obtained at optimized conditions varied between 29.25- 97.28% at static condition and 82.1- 100% at shaking condition. Sodium dodecyl sulphate polyacrylamide gel electrophoretic analysis revealed bands with molecular weights ranging between 66.5 to 71 kDa, a characteristic of the fungal laccases. High efficiency decolourisation of Congo red makes these fungal forms a promising choice in biological treatment of waste water containing Congo red.

  13. Mycoremediation of Congo red dye by filamentous fungi

    Directory of Open Access Journals (Sweden)

    Sourav Bhattacharya

    2011-12-01

    Full Text Available Azo, anthroquinone and triphenylmethane dyes are the major classes of synthetic colourants, which are difficult to degrade and have received considerable attention. Congo red, a diazo dye, is considered as a xenobiotic compound, and is recalcitrant to biodegradative processes. Nevertheless, during the last few years it has been demonstrated that several fungi, under certain environmental conditions, are able to transfer azo dyes to non toxic products using laccases. The aim of this work was to study the factors influencing mycoremediation of Congo red. Several basidiomycetes and deuteromycetes species were tested for the decolourisation of Congo red (0.05 g/l in a semi synthetic broth at static and shaking conditions. Poor decolourisation was observed when the dye acted as the sole source of nitrogen, whereas semi synthetic broth supplemented with fertilizer resulted in better decolourisation. Decolourisation of Congo red was checked in the presence of salts of heavy metals such as mercuric chloride, lead acetate and zinc sulphate. Decolourisation parameters such as temperature, pH, and rpm were optimized and the decolourisation obtained at optimized conditions varied between 29.25- 97.28% at static condition and 82.1- 100% at shaking condition. Sodium dodecyl sulphate polyacrylamide gel electrophoretic analysis revealed bands with molecular weights ranging between 66.5 to 71 kDa, a characteristic of the fungal laccases. High efficiency decolourisation of Congo red makes these fungal forms a promising choice in biological treatment of waste water containing Congo red.

  14. Congo red and protein aggregation in neurodegenerative diseases.

    Science.gov (United States)

    Frid, Petrea; Anisimov, Sergey V; Popovic, Natalija

    2007-01-01

    Congo red is a commonly used histological dye for amyloid detection. The specificity of this staining results from Congo red's affinity for binding to fibril proteins enriched in beta-sheet conformation. Unexpectedly, recent investigations indicate that the dye also possesses the capacity to interfere with processes of protein misfolding and aggregation, stabilizing native protein monomers or partially folded intermediates, while reducing concentration of more toxic protein oligomers. Inhibitory effects of Congo red upon amyloid toxicity may also range from blockade of channel formation and interference with glycosaminoglycans binding or immune functions, to the modulation of gene expression. Particularly, Congo red exhibits ameliorative effect in models of neurodegenerative disorders, such as Alzheimer's, Parkinson's, Huntington's and prion diseases. Another interesting application of Congo red analogues is the development of imaging probes. Based on their small molecular size and penetrability through blood-brain barrier, Congo red congeners can be used for both antemortem and in vivo visualization and quantification of brain amyloids. Therefore, understanding mechanisms involved in dye-amyloidal fibril binding and inhibition of aggregation will provide instructive guides for the design of future compounds, potentially useful for monitoring and treating neurodegenerative diseases.

  15. Gestion participative du sanctuaire de gorilles de plaine de l'ouest (Gorilla gorilla gorilla de Lossi en République du Congo- Brazzaville: première analyse de résultats et des contraintes

    Directory of Open Access Journals (Sweden)

    Mbété, RA.

    2007-01-01

    Full Text Available Participative Management of the Sanctuary of Western Lowland Gorillas (Gorilla gorilla gorilla of Lossi in Republic of Congo-Brazzaville: Preliminary Results and Constraints Analysis. The gorilla sanctuary of Lossi experiments the synergy between scientific research and nature conservation. Three partners are involved in a management participative process. These partners include the Republic of Congo, the local community of Lossi and the European programme on the forest ecosystems in Central Africa. An investigation was carried out on the sanctuary of Lossi in 2003, in order to study in situ the effects generated by the participative management and to identify the constraints linked to the participative approach. The work of primatologists allowed the habituation of the gorillas to the human presence and opened eyesight tourism of western lowland gorillas. A camp for tourists and the access road to the sanctuary have been constructed. The tourism generated jobs in favour of the local population which is also a take-partner of contracts on road repairing. The income from the tourism allowed the construction of a health centre. However, the works of researchers and tourism activities failed during the outbreaks of the Ebola hemorrhagic fever and during the three civil war episodes. The consolidation and the long term of this process of co-management of natural resources of Lossi remains the establishment of a management that should include conservation, rural development and scientific research, with equitably in the distribution of gain between the partnerses.

  16. Dental lesions in the lowland tapir (Tapirus terrestris)

    DEFF Research Database (Denmark)

    Tjørnelund, Karen B.; Jonsson, Lena M.; Kortegaard, Hanne Ellen

    2015-01-01

    Dental ailments, mandibular swelling, and dentoalveolar abscesses are common in tapirs, but knowledge about prevalence or etiology of these lesions in the Tapiridae family in general, and in lowland tapirs ( Tapirus terrestris ) in particular, is scarce. A recent study identified resorptive lesions...... of unknown etiology as a common problem in the Malayan tapir ( Tapirus indicus ). In order to investigate the type and prevalence of dental lesions occurring in lowland tapirs, and to compare these with findings with the Malayan tapir, skulls and teeth from 46 deceased lowland tapirs were visually...... with associated periapical reaction (15%) and periapical reactions of various degrees without associated detectable dental pathology (13%). All these lesions likely originated from dental trauma. As in Malayan tapirs, juveniles had significantly fewer lesions than adults. This study shows that dental lesions...

  17. Tropical forest soil microbes and climate warming: An Andean-Amazon gradient and `SWELTR'

    Science.gov (United States)

    Nottingham, A.; Turner, B. L.; Fierer, N.; Whitaker, J.; Ostle, N. J.; McNamara, N. P.; Bardgett, R.; Silman, M.; Bååth, E.; Salinas, N.; Meir, P.

    2017-12-01

    Climate warming predicted for the tropics in the coming century will result in average temperatures under which no closed canopy forest exists today. There is, therefore, great uncertainty associated with the direction and magnitude of feedbacks between tropical forests and our future climate - especially relating to the response of soil microbes and the third of global soil carbon contained in tropical forests. While warming experiments are yet to be performed in tropical forests, natural temperature gradients are powerful tools to investigate temperature effects on soil microbes. Here we draw on studies from a 3.5 km elevation gradient - and 20oC mean annual temperature gradient - in Peruvian tropical forest, to investigate how temperature affects the structure of microbial communities, microbial metabolism, enzymatic activity and soil organic matter cycling. With decreased elevation, soil microbial diversity increased and community composition shifted, from taxa associated with oligotrophic towards copiotrophic traits. A key role for temperature in shaping these patterns was demonstrated by a soil translocation experiment, where temperature-manipulation altered the relative abundance of specific taxa. Functional implications of these community composition shifts were indicated by changes in enzyme activities, the temperature sensitivity of bacterial and fungal growth rates, and the presence of temperature-adapted iso-enzymes at different elevations. Studies from a Peruvian elevation transect indicated that soil microbial communities are adapted to long-term (differences with elevation) and short-term (translocation responses) temperature changes. These findings indicate the potential for adaptation of soil microbes in tropical soils to future climate warming. However, in order to evaluate the sensitivity of these processes to climate warming in lowland forests, in situ experimentation is required. Finally, we describe SWELTR (Soil Warming Experiment in Lowland

  18. Classic Maya civilization collapse associated with reduction in tropical cyclone activity

    Science.gov (United States)

    Medina, M. A.; Polanco-Martinez, J. M.; Lases-Hernández, F.; Bradley, R. S.; Burns, S. J.

    2013-12-01

    In light of the increased destructiveness of tropical cyclones observed over recent decades one might assume that an increase and not a decrease in tropical cyclone activity would lead to societal stress and perhaps collapse of ancient cultures. In this study we present evidence that a reduction in the frequency and intensity of tropical Atlantic cyclones could have contributed to the collapse of the Maya civilization during the Terminal Classic Period (TCP, AD. 800-950). Statistical comparisons of a quantitative precipitation record from the Yucatan Peninsula (YP) Maya lowlands, based on the stalagmite known as Chaac (after the Mayan God of rain and agriculture), relative to environmental proxy records of El Niño/Southern Oscillation (ENSO), tropical Atlantic sea surface temperatures (SSTs), and tropical Atlantic cyclone counts, suggest that these records share significant coherent variability during the TCP and that summer rainfall reductions between 30 and 50% in the Maya lowlands occurred in association with decreased Atlantic tropical cyclones. Analysis of modern instrumental hydrological data suggests cyclone rainfall contributions to the YP equivalent to the range of rainfall deficits associated with decreased tropical cyclone activity during the collapse of the Maya civilization. Cyclone driven precipitation variability during the TCP, implies that climate change may have triggered Maya civilization collapse via freshwater scarcity for domestic use without significant detriment to agriculture. Pyramid in Tikal, the most prominent Maya Kingdom that collapsed during the Terminal Classic Period (circa C.E. 800-950) Rainfall feeding stalagmites inside Rio Secreto cave system, Yucatan, Mexico.

  19. Mars: destruction of the tropical belt and building up extra tropics is a physical requirement of angular momentum equilibration between zones with different distances to the rotation axis

    Science.gov (United States)

    Kochemasov, G. G.

    2012-09-01

    Often observed a sensible difference in appearance and structure between tropical and extra-t ropical zones of various heavenly bodies including rocky and gas planets, satellites and Sun (Fig. 6) compels to look for a common reason of such phenomenon [1-3]. All bodies rotate and their spherical shape makes zones at different lat itudes to have differing angular momenta as a distance to the rotation axis diminishes gradually from the equator to the poles (Fig. 1) (this is felt particularly when one launches rockets into space -preferable cheaper launches are from the equatorial regions - Kourou in the French Guyana is better than Baikonur in Kazakhstan). One of remarkable changes occurs at tropics. As a total rotating planetary body tends to have angular momenta of its tectonic blocks equilibrated it starts mechanisms leveling this basic physical property. At tropical zones (bulged also due to the rotation ellipsoid) the outer shell - crust as a consequence tends to be destroyed, sunk, subsided and shrunk; a density of crust material changes; the atmosphere reacts changing chemistry and structure; in terrestrial anthroposphere man looses its mass and stature (well known pygmioidness process). Ext ratropical belts, on the contrary, tend to add material and increase radius. Thus, a body tends to be like a cucumber but mighty gravity always makes it globular. According to the Le Chatelier rule mechanisms with opposing tendencies also begin to act. However, traces of this cosmic "struggle" very often are seen on surfaces of heavenly bodies as structurally distinguished tropical and extra-t ropical zones (Fig. 1, 6) [1-3]. At Mars the widespread "enigmatic" chaotic and fretted terrains at the highland-lowland boundary could be considered as traces of the crust destruction along the wide tropical belt (Fig. 2-4). A system of hillocks and their relics, mesas, ridges, cliffs and separating them depressions or plains (deep up to 1-2 km) is controlled by a crosscutting

  20. Bird Responses to Lowland Rainforest Conversion in Sumatran Smallholder Landscapes, Indonesia.

    Science.gov (United States)

    Prabowo, Walesa Edho; Darras, Kevin; Clough, Yann; Toledo-Hernandez, Manuel; Arlettaz, Raphael; Mulyani, Yeni A; Tscharntke, Teja

    2016-01-01

    Rapid land-use change in the tropics causes dramatic losses in biodiversity and associated functions. In Sumatra, Indonesia, lowland rainforest has mainly been transformed by smallholders into oil palm (Elaeis guineensis) and rubber (Hevea brasiliensis) monocultures, interspersed with jungle rubber (rubber agroforests) and a few forest remnants. In two regions of the Jambi province, we conducted point counts in 32 plots of four different land-use types (lowland rainforest, jungle rubber, rubber plantation and oil palm plantation) as well as in 16 nearby homegardens, representing a small-scale, traditional agricultural system. We analysed total bird abundance and bird abundance in feeding guilds, as well as species richness per point count visit, per plot, and per land-use system, to unveil the conservation importance and functional responses of birds in the different land-use types. In total, we identified 71 species from 24 families. Across the different land-use types, abundance did not significantly differ, but both species richness per visit and per plot were reduced in plantations. Feeding guild abundances between land-use types were variable, but homegardens were dominated by omnivores and granivores, and frugivorous birds were absent from monoculture rubber and oil palm. Jungle rubber played an important role in harbouring forest bird species and frugivores. Homegardens turned out to be of minor importance for conserving birds due to their low sizes, although collectively, they are used by many bird species. Changes in functional composition with land-use conversion may affect important ecosystem functions such as biological pest control, pollination, and seed dispersal. In conclusion, maintaining forest cover, including degraded forest and jungle rubber, is of utmost importance to the conservation of functional and taxonomic bird diversity.

  1. Bird Responses to Lowland Rainforest Conversion in Sumatran Smallholder Landscapes, Indonesia

    Science.gov (United States)

    Clough, Yann; Toledo-Hernandez, Manuel; Arlettaz, Raphael; Mulyani, Yeni A.; Tscharntke, Teja

    2016-01-01

    Rapid land-use change in the tropics causes dramatic losses in biodiversity and associated functions. In Sumatra, Indonesia, lowland rainforest has mainly been transformed by smallholders into oil palm (Elaeis guineensis) and rubber (Hevea brasiliensis) monocultures, interspersed with jungle rubber (rubber agroforests) and a few forest remnants. In two regions of the Jambi province, we conducted point counts in 32 plots of four different land-use types (lowland rainforest, jungle rubber, rubber plantation and oil palm plantation) as well as in 16 nearby homegardens, representing a small-scale, traditional agricultural system. We analysed total bird abundance and bird abundance in feeding guilds, as well as species richness per point count visit, per plot, and per land-use system, to unveil the conservation importance and functional responses of birds in the different land-use types. In total, we identified 71 species from 24 families. Across the different land-use types, abundance did not significantly differ, but both species richness per visit and per plot were reduced in plantations. Feeding guild abundances between land-use types were variable, but homegardens were dominated by omnivores and granivores, and frugivorous birds were absent from monoculture rubber and oil palm. Jungle rubber played an important role in harbouring forest bird species and frugivores. Homegardens turned out to be of minor importance for conserving birds due to their low sizes, although collectively, they are used by many bird species. Changes in functional composition with land-use conversion may affect important ecosystem functions such as biological pest control, pollination, and seed dispersal. In conclusion, maintaining forest cover, including degraded forest and jungle rubber, is of utmost importance to the conservation of functional and taxonomic bird diversity. PMID:27224063

  2. Bird Responses to Lowland Rainforest Conversion in Sumatran Smallholder Landscapes, Indonesia.

    Directory of Open Access Journals (Sweden)

    Walesa Edho Prabowo

    Full Text Available Rapid land-use change in the tropics causes dramatic losses in biodiversity and associated functions. In Sumatra, Indonesia, lowland rainforest has mainly been transformed by smallholders into oil palm (Elaeis guineensis and rubber (Hevea brasiliensis monocultures, interspersed with jungle rubber (rubber agroforests and a few forest remnants. In two regions of the Jambi province, we conducted point counts in 32 plots of four different land-use types (lowland rainforest, jungle rubber, rubber plantation and oil palm plantation as well as in 16 nearby homegardens, representing a small-scale, traditional agricultural system. We analysed total bird abundance and bird abundance in feeding guilds, as well as species richness per point count visit, per plot, and per land-use system, to unveil the conservation importance and functional responses of birds in the different land-use types. In total, we identified 71 species from 24 families. Across the different land-use types, abundance did not significantly differ, but both species richness per visit and per plot were reduced in plantations. Feeding guild abundances between land-use types were variable, but homegardens were dominated by omnivores and granivores, and frugivorous birds were absent from monoculture rubber and oil palm. Jungle rubber played an important role in harbouring forest bird species and frugivores. Homegardens turned out to be of minor importance for conserving birds due to their low sizes, although collectively, they are used by many bird species. Changes in functional composition with land-use conversion may affect important ecosystem functions such as biological pest control, pollination, and seed dispersal. In conclusion, maintaining forest cover, including degraded forest and jungle rubber, is of utmost importance to the conservation of functional and taxonomic bird diversity.

  3. Clutch size declines with elevation in tropical birds

    Science.gov (United States)

    Boyce, A.J.; Freeman, Benjamin G.; Mitchell, Adam E.; Martin, Thomas E.

    2015-01-01

    Clutch size commonly decreases with increasing elevation among temperate-zone and subtropical songbird species. Tropical songbirds typically lay small clutches, thus the ability to evolve even smaller clutch sizes at higher elevations is unclear and untested. We conducted a comparative phylogenetic analysis using data gathered from the literature to test whether clutch size varied with elevation among forest passerines from three tropical biogeographic regions—the Venezuelan Andes and adjacent lowlands, Malaysian Borneo, and New Guinea. We found a significant negative effect of elevation on variation in clutch size among species. We found the same pattern using field data sampled across elevational gradients in Venezuela and Malaysian Borneo. Field data were not available for New Guinea. Both sets of results demonstrate that tropical montane species across disparate biogeographic realms lay smaller clutches than closely related low-elevation species. The environmental sources of selection underlying this pattern remain uncertain and merit further investigation.

  4. Sediment composition mediated land use effects on lowland streams ecosystems

    NARCIS (Netherlands)

    Dos Reis Oliveira, P.C.; Kraak, M.H.S.; van der Geest, H.G.; Naranjo, S.; Verdonschot, P.F.M

    2018-01-01

    Despite the widely acknowledged connection between terrestrial and aquatic ecosystems, the contribution of runoff to the sediment composition in lowland stream deposition zones and the subsequent effects on benthic invertebrates remain poorly understood. The aim of this study was therefore to

  5. Geochemical and hydrodynamic phosphorus retention mechanisms in lowland catchments

    NARCIS (Netherlands)

    van der Grift, B.

    2017-01-01

    The release of phosphorus (P) to surface water from heavily fertilised agricultural fields is of major importance for surface water quality. The research reported in this thesis examined the role of geochemical and hydrodynamic processes controlling P speciation and transport in lowland catchments

  6. Effects of riparian vegetation development in a restored lowland stream

    NARCIS (Netherlands)

    Vargas-Luna, A.; Crosato, A.; Hoitink, A.J.F.; Groot, J.; Uijttewaal, W.S.J.

    2016-01-01

    This paper presents the morphodynamic effects of riparian vegetation growth in a lowland restored stream. Hydrological series, high-resolution bathymetric data and aerial photographs are combined in the study. The vegetation root system was found to assert a strong control on soil stabilization,

  7. Lowland riparian herpetofaunas: the San Pedro River in southeastern Arizona

    Science.gov (United States)

    Philip C. Rosen

    2005-01-01

    Previous work has shown that southeastern Arizona has a characteristic, high diversity lowland riparian herpetofauna with 62-68 or more species along major stream corridors, and 46-54 species in shorter reaches within single biomes, based on intensive fieldwork and museum record surveys. The San Pedro River supports this characteristic herpetofauna, at least some of...

  8. Soil microbial diversity patterns of a lowland spring environment

    NARCIS (Netherlands)

    Vasileiadis, S.; Puglisi, E.; Arena, M.; Cappa, F.; Van Veen, J.A.; Cocconcelli, P.S.; Trevisan, M.

    2013-01-01

    The Po river plain lowland springs represent unique paradigms of managed environments. Their current locations used to be swamps that were drained 6–7 centuries ago, and they have been in constant use ever since. Our aims were to identify the effects of land use on the microbial communities of these

  9. agronomic performance of introduced banana varieties in lowlands

    African Journals Online (AJOL)

    jen

    this study was to evaluate the agronomic performance of FHIA hybrids in lowlands of Rwanda. Completely ... L'objectif de cette étude était d'évaluer la performance agronomique de FHIA hybride ..... major Musa types present in Asia and the.

  10. Surgical extractions for periodontal disease in a Western Lowland gorilla.

    Science.gov (United States)

    Huff, John F

    2010-01-01

    This case report describes surgical exraction of multiple premolar and molar teeth in a Western Lowland gorilla. Postoperative photographs and radiographs indicated complete healing of the extraction sites. This case report includes a review of gorilla dental anatomy, oral disease in primates, pathogenesis of periodontal disease, predisposing factors to periodontal disease, and principles of surgical tooth extraction.

  11. An Indian Federation in Lowland Ecuador. IWGIA Document 28.

    Science.gov (United States)

    Salazar, Ernesto

    Official involvement of the Ecuadorian government with colonization of the southern lowlands, lands traditionally belonging to the Shuar Indians, began in the early 60's when the CREA (Centro de Reconversion Economica del Azuay) was created to provide assistance to white settlers. Until that time, the Shuar lands had been dominated by the Salesian…

  12. Radiation degradation of Congo Red in aqueous solution

    International Nuclear Information System (INIS)

    Ma Hongjuan; Wang Min; Yang Ruiyuan; Wang Wenfeng; Shen Zhongqun; Yao Side

    2006-01-01

    About one-half of the dyes used in textile industry are azo dyes, and as a consequence a lot of azo dyes are released into the environment with industrial wastewater. Because of complex structures of the dyes, biological, physical and chemical treatments of dye effluents are inefficient. In this study, radiation degradation of Congo Red in aqueous solutions was investigated in different reaction systems. Both pulsed radiolysis and laser flash photolysis experiments were carried out for better understandings of degradation mechanisms involved in the treatments. Congo Red solutions saturated by air, N 2 O, O 2 , N 2 O or N 2 and added with tert-butanol were irradiated to 0-14.8 kGy. The absorption spectra, degradation efficiency, TOC (total organic carbon) removal and pH changes of the solutions were investigated. The main radiolytic products from Congo Red samples irradiated in steady-state were determined by HPLC-MS. And probable reaction mechanisms were proposed. Effects of primary species from water radiolysis, such as e aq - , . OH and . O 2 . /HO 2 . on the degradation behavior of the dye were discussed. Below 5 kGy in γ-rays irradiation, the bleaching efficiency of Congo Red was (N 2 +tert-butanol) >O 2 >air>N 2 O>N 2 . Complete degradation of Congo Red was observed at 4.0, 5.5 and 10.2 kGy irradiation of the aqueous solutions saturated by N 2 with tert-butanol added, O 2 and N 2 O, respectively. With just oxidative or reductive species, highly conjugated part of Congo Red molecules could be destroyed. While oxidative species produced from water radiolysis could oxidize the Congo Red more effectively, making the dye to break into fatty acids and CO 2 finally. In the solution saturated with N 2 and air, the primary active species were both of oxidative and reductive and the highly conjugated part of Congo Red molecules could not be destroyed completely up to 14.8 kGy of γ-ray irradiation. It was more difficult to achieve high TOC removal in comparison with

  13. Groundwater Quality of Southeastern Brazzaville, Congo

    Directory of Open Access Journals (Sweden)

    Matini Laurent

    2010-01-01

    Full Text Available The groundwater in southeastern Brazzaville (Congo was analyzed for their fluoride contents and others related parameters in rainy season. The fluoride contents in water samples (wells and spring can be gather in three classes in the study area: low, optimal, high. Fluoride concentration in water samples presents a low significant correlation with Ca2+. This suggests that fluoride in the groundwater come from fluoride-bearing minerals such as CaF2 (fluorite. Maps were drawn to show the geographical distribution of EC, Ca2+, Mg2+and F-. Factor analysis and cluster analysis were applied to the dataset. Factor analysis resulted in four factors explained 76.90% of the total groundwater quality variance. Factor 1 (hardness of the groundwater includes total hardness, the concentration of K+, Ca2+ and pH. Factor 2 (low mineralization of the groundwater includes concentrations of TDS, Cl--, SO42+ and EC. Factor 3 (anthropogenic activities with the impact of agricultural fertilizers, farming activities, domestic wastewater, septic tanks includes concentrations of Na+ and NO3-. Factor 4 (weathering of calcium minerals includes concentrations of F-. For cluster analysis, Ward’s method and the Euclidean distance were used. The findings of the cluster analysis are presented in the form of dendrogram of the well water sites (cases. The discriminating parameters between clusters have been highlighted from the Student test. In majority, they are in accordance with those highlighted by factor analysis.

  14. Congo crimean hemorrhagic fever in balochistan

    International Nuclear Information System (INIS)

    Durrani, A.B.; Shaikh, M.; Khan, Z.

    2007-01-01

    To observe the pattern and mortality of Congo-Crimean Hemorrhagic Fever (CCHF) in Balochistan. Two hundred and twenty-six febrile patients with bleeding of sudden onset, with initial signs and symptoms including headache, high fever, back pain, joint pain, stomach pain, vomiting, red eyes, flushed face, red throat and petechiae on the palate of both sexes were screened for CCHF over a period of 10 years. Clinical criteria for initial diagnosis directed the subsequent diagnostic work-up. The ages of these patients ranged from 7 years to 74 years. Sixty-three percent of these patients were positive for CCHF. Males were 68% of the total patients. Over the years, CCHF showed a gradual increase ranging from 43% to 80%. Total mortality was 15%, all being secondary cases. Death was not observed in primary CCHF cases. In this study, suspicion of viral hemorrhagic fever was raised in 62% cases at the time of admission and the patients were immediately isolated, noninvasive procedures were instigated and barrier nursing was implemented. None of the family and hospital staff members who had close contact with the patient became ill, while those who were not suspected initially (38%) infected the health care workers and the family members. Although CCHF is rare, this study stresses the need for proper health facilities in Pakistan and to include VHF (viral hemorrhagic fevers) in the differential diagnosis of unexplained fever with hemorrhagic tendencies of sudden onset. (author)

  15. Evaluating private land conservation in the Cape Lowlands, South Africa.

    Science.gov (United States)

    Von Hase, Amrei; Rouget, Mathieu; Cowling, Richard M

    2010-10-01

    Evaluation is important for judiciously allocating limited conservation resources and for improving conservation success through learning and strategy adjustment. We evaluated the application of systematic conservation planning goals and conservation gains from incentive-based stewardship interventions on private land in the Cape Lowlands and Cape Floristic Region, South Africa. We collected spatial and nonspatial data (2003-2007) to determine the number of hectares of vegetation protected through voluntary contractual and legally nonbinding (informal) agreements with landowners; resources spent on these interventions; contribution of the agreements to 5- and 20-year conservation goals for representation and persistence in the Cape Lowlands of species and ecosystems; and time and staff required to meet these goals. Conservation gains on private lands across the Cape Floristic Region were relatively high. In 5 years, 22,078 ha (27,800 ha of land) and 46,526 ha (90,000 ha of land) of native vegetation were protected through contracts and informal agreements, respectively. Informal agreements often were opportunity driven and cheaper and faster to execute than contracts. All contractual agreements in the Cape Lowlands were within areas of high conservation priority (identified through systematic conservation planning), which demonstrated the conservation plan's practical application and a high level of overlap between resource investment (approximately R1.14 million/year in the lowlands) and priority conservation areas. Nevertheless, conservation agreements met only 11% of 5-year and 9% of 20-year conservation goals for Cape Lowlands and have made only a moderate contribution to regional persistence of flora to date. Meeting the plan's conservation goals will take three to five times longer and many more staff members to maintain agreements than initially envisaged. © 2010 Society for Conservation Biology.

  16. Biogenic VOC Emissions from Tropical Landscapes

    Science.gov (United States)

    Guenther, A.; Greenberg, J.; Harley, P.; Otter, L.; Vanni Gatti, L.; Baker, B.

    2003-04-01

    Biogenic VOC have an important role in determining the chemical composition of atmosphere. As a result, these compounds are important for visibility, biogeochemical cycling, climate and radiative forcing, and the health of the biosphere. Tropical landscapes are estimated to release about 80% of total global biogenic VOC emissions but have been investigated to lesser extent than temperate regions. Tropical VOC emissions are particularly important due to the strong vertical transport and the rapid landuse change that is occurring there. This presentation will provide an overview of field measurements of biogenic VOC emissions from tropical landscapes in Amazonia (Large-scale Biosphere-atmosphere experiment in Amazonia, LBA) Central (EXPRESSO) and Southern (SAFARI 2000) Africa, Asia and Central America. Flux measurement methods include leaf-scale (enclosure measurements), canopy-scale (above canopy tower measurements), landscape-scale (tethered balloon), and regional-scale (aircraft measurements) observations. Typical midday isoprene emission rates for different landscapes vary by more than a factor of 20 with the lowest emissions observed from degraded forests. Emissions of alpha-pinene vary by a similar amount with the highest emissions associated with landscapes dominated by light dependent monoterpene emitting plants. Isoprene emissions tend to be higher for neotropical forests (Amazon and Costa Rica) in comparison to Africa and Asian tropical forests but considerable differences are observed within regions. Strong seasonal variations were observed in both the Congo and the Amazon rainforests with peak emissions during the dry seasons. Substantial emissions of light dependent monoterpenes, methanol and acetone are characteristic of at least some tropical landscapes.

  17. Man and climate in the Maya lowlands

    Science.gov (United States)

    Leyden, Barbara W.

    1987-11-01

    A 15-m sedimentary core from Lake Salpeten provides the first complete Holocene sequence for the lowlying Peten District, Guatemala. Today, Lake Salpeten is a brackish, calcium sulfate lake near saturation surrounded by tropical semievergreen forest. The basal pollen record depicts sparse juniper scrub surrounding a lake basin that held ephermal pools and halophytic marshes. The lake rapidly deepened to > 27 m in the early Holocene and may have been meromictic, because nearly 2 m of gypsum "mush" was deposited. Mesic forests were quickly established and persisted until the Maya entered the district 3000 yr ago and caused extensive deforestation. Any climatic information contained in the pollen record of the Maya period is thus masked, but a regional pollen sequence linked to the archaeological record is substantiated because environmental disturbance was pervasive. Local intensification of occupation and population growth are seen as an increased deposition of pollen of agricultural weeds and colluviation into the lake, while the Classic Maya collapse is marked by a temporary decline in Compositae pollen. Effects of perturbations induced by the Maya persist in the pollen and limnetic record 400 yr after the Spanish conquest.

  18. The effect of Congo River freshwater discharge on Eastern Equatorial Atlantic climate variability

    Energy Technology Data Exchange (ETDEWEB)

    Materia, Stefano [Centro Euro-Mediterraneo per i Cambiamenti Climatici, Bologna (Italy); Gualdi, Silvio; Navarra, Antonio [Centro Euro-Mediterraneo per i Cambiamenti Climatici, Bologna (Italy); Istituto Nazionale di Geofisica e Vulcanologia, Bologna (Italy); Terray, Laurent [Sciences de l' Univers au CERFACS, URA1875 CERFACS/CNRS, Toulouse (France)

    2012-11-15

    The surface ocean explains a considerable part of the inter-annual Tropical Atlantic variability. The present work makes use of observational datasets to investigate the effect of freshwater flow on sea surface salinity (SSS) and temperature (SST) in the Gulf of Guinea. In particular, the Congo River discharges a huge amount of freshwater into the ocean, affecting SSS in the Eastern Equatorial Atlantic (EEA) and stratifying the surface layers. The hypothesis is that an excess of river runoff emphasize stratification, influencing the ocean temperature. In fact, our findings show that SSTs in the Gulf of Guinea are warmer in summers following an anomalously high Congo spring discharge. Vice versa, when the river discharges low freshwater, a cold anomaly appears in the Gulf. The response of SST is not linear: temperature anomalies are considerable and long-lasting in the event of large freshwater flow, while in dry years they are less remarkable, although still significant. An excess of freshwater seems able to form a barrier layer, which inhibits vertical mixing and the entrainment of the cold thermocline water into the surface. Other processes may contribute to SST variability, among which the net input of atmospheric freshwater falling over EEA. Likewise the case of continental runoff from Congo River, warm anomalies occur after anomalously rainy seasons and low temperatures follow dry seasons, confirming the effect of freshwater on SST. However, the two sources of freshwater anomaly are not in phase, so that it is possible to split between atypical SST following continental freshwater anomalies and rainfall anomalies. Also, variations in air-sea fluxes can produce heating and cooling of the Gulf of Guinea. Nevertheless, atypical SSTs cannot be ascribed to fluxes, since the temperature variation induced by them is not sufficient to explain the SST anomalies appearing in the Gulf after anomalous peak discharges. The interaction processes between river runoff, sea

  19. Chemical composition of the mineral waters of the Congo River

    International Nuclear Information System (INIS)

    Tshiashala, M.D.; Lumu, B.M.; Lobo, K.K.; Tshisumpa, M.; Wembo, L.S.

    2003-01-01

    Atomic absorption spectrophotometry has been applied to river Congo waters for a global monitoring of trace element contents. 15 elements Ag, Au, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb and Zn have been determined in samples collected at 2 sites along the river Congo. Results are compared with those observed in other river waters collected in Kinshasa and elsewhere and for compliance with the international quality standards elaborated by the Who, USA and SSRU. The waters of river Congo have been found less mineralized than those of river Niger. They are of the same order of magnitude than those observed in some local rivers such as Ndjili, Lubudi, Funa, Tshangu and Tshenke.

  20. Variations des apports de litière et d'éléments minéraux dans les plantations de limba (Terminalia superba au Congo

    Directory of Open Access Journals (Sweden)

    Kokolo, A.

    2005-01-01

    Full Text Available Variations in Litter Production and Nutrient Supply in Plantations of Limba (Terminalia superba in Congo. A study was carried out in a chronosequence of Terminalia superba (7, 12 and 48 years and a nearby natural forest. The results show that the peaks of litterfall take place in rainy season contrary to the majority of the forest formations of the humid tropical zone. The return of nutrients to the soil via the leaf litter is higher in plantations than in forest. The calcium released from the leaf litter was up to 175 kg.ha-1.year1. The values obtained indicate a moderate nutrient use efficiency by Terminalia superba.

  1. Palm Harvest Impact on Tropical Forests

    DEFF Research Database (Denmark)

    Balslev, Henrik; Eiserhardt, Wolf L.

    Palms are the most useful group of plants in tropical American forests and in this project we study the effect of extraction and trade of palms on forest in the western Amazon, Andes and Pacific lowlands. We determine the size of the resource by making palm community studies in the different forest...... formations and determine the number of species and individuals of all palm species. The genetic structure of useful palm species is studied to determine how much harvesting of the species contributes to genetic erosion of its populations, and whether extraction can be made without harm. We determine how much...... palms are used for subsistence purposes by carrying out quantitative, ethnobotanical research in different forest types and we also study trade patterns for palm products from local markets to markets that involve export to other countries and continents. We study different ways in which palms...

  2. [Emerging diseases. Crimean-Congo hemorrhagic fever].

    Science.gov (United States)

    Kuljić-Kapulica, Nada

    2004-01-01

    Recognized for many years in central Asia and Eastern Europe, Crimean-Congo hemorrhagic fever (CCHF) is a severe zoonotic disease which affects people coming into contact with livestock or ticks. The range of the CCHF virus is now known to extend form central Asia to India, Pakistan, Afghanistan, Iran, Iraq, the Middle East, Eastern Europe, and to most of Saharan and sub-Saharan Africa. CCHF virus is a member of the Bunyavirus family, and is classified as a Nairovirus. After an incubation period of approximately 3 to 6 days the abrupt onset of acute febrile illness occurs. The first symptoms are similar to severe influenza and include fever, headache, severe back and abdominal pain. The hemorrhagic fever manifestations occur after several days of illnesses and include petechial rash, ecchymoses, hematemmesis, and melenna. Cases typically present with some form of hepatitis. The mortality rate is 10-50% in different outbreaks with deaths typically occurring during the second week of illness. The genus Hyalomma of ixodid ticks is the most important vector of the CCHF virus. Vertebrates including birds and small animals provide excellent amplifier hosts of both the virus and the tick. The virus can be transmitted to humans by direct contact with infected animals and from person to person. Early diagnosis is possible in special laboratories using antigen detection by imunofluorescence or ELISA tests or molecular methods as PCR and antibody detection. Tick control measures need to be emphasized and utilized to prevent CCHF. This includes spraying camp sites, clothing and danger areas with acaricides or repellent. Strict isolation of patients with CCHF and a focus on barrier nursing would help to prevent nosocomial spread. Presently the vaccine is a dangerous mouse brain-derived version. Future development of a vaccine would help to prevent human infection.

  3. Large lianas as hyperdynamic elements of the tropical forest canopy

    OpenAIRE

    Phillips, O.L.; Vásquez Martínez, R.; Monteagudo Mendoza, A.; Baker, T.R.; Núñez Vargas, P.

    2005-01-01

    Lianas (woody vines) are an important component of lowland tropical forests.\\ud We report large liana and tree inventory and dynamics data from Amazonia over periods\\ud of up to 24 years, making this the longest geographically extensive study of liana ecology\\ud to date. We use these results to address basic questions about the ecology of large lianas\\ud in mature forests and their interactions with trees. In one intensively studied site we find\\ud that large lianas (≥10 cm diameter) represen...

  4. Geophagy in brown spider monkeys (Ateles hybridus) in a lowland tropical rainforest in Colombia.

    Science.gov (United States)

    Link, Andres; de Luna, Ana Gabriela; Arango, Ricardo; Diaz, Maria Clara

    2011-01-01

    Spider monkeys and howler monkeys are the only Neotropical primates that eat soil from mineral licks. Not all species within these genera visit mineral licks, and geophagy has been restricted to populations of Ateles belzebuth belzebuth,Ateles belzebuth chamek and Alouatta seniculus in western Amazonian rainforests. With the aid of a camera trap we studied the visitation patterns of a group of brown spider monkeys (Ateles hybridus) to a mineral lick at Serrania de Las Quinchas, in Colombia. Spider monkeys visited the lick frequently throughout the year, with a monthly average of 21.7 ± 7.2 visits per 100 days of camera trapping (n = 14 months). Spider monkeys visited the mineral lick almost always on days with no rain, or very little (<3 mm) rain, suggesting that proximate environmental variables might determine spider monkeys' decisions to come to the ground at the licks. This study expands the geographical occurrence of mineral lick use by spider monkeys providing additional data for future assessments on the biogeographical correlates of mineral lick use by platyrrhines. Copyright © 2011 S. Karger AG, Basel.

  5. Phylogenetic analysis of local-scale tree soil associations in a lowland moist tropical forest.

    Directory of Open Access Journals (Sweden)

    Laura A Schreeg

    Full Text Available BACKGROUND: Local plant-soil associations are commonly studied at the species-level, while associations at the level of nodes within a phylogeny have been less well explored. Understanding associations within a phylogenetic context, however, can improve our ability to make predictions across systems and can advance our understanding of the role of evolutionary history in structuring communities. METHODOLOGY/PRINCIPAL FINDINGS: Here we quantified evolutionary signal in plant-soil associations using a DNA sequence-based community phylogeny and several soil variables (e.g., extractable phosphorus, aluminum and manganese, pH, and slope as a proxy for soil water. We used published plant distributional data from the 50-ha plot on Barro Colorado Island (BCI, Republic of Panamá. Our results suggest some groups of closely related species do share similar soil associations. Most notably, the node shared by Myrtaceae and Vochysiaceae was associated with high levels of aluminum, a potentially toxic element. The node shared by Apocynaceae was associated with high extractable phosphorus, a nutrient that could be limiting on a taxon specific level. The node shared by the large group of Laurales and Magnoliales was associated with both low extractable phosphorus and with steeper slope. Despite significant node-specific associations, this study detected little to no phylogeny-wide signal. We consider the majority of the 'traits' (i.e., soil variables evaluated to fall within the category of ecological traits. We suggest that, given this category of traits, phylogeny-wide signal might not be expected while node-specific signals can still indicate phylogenetic structure with respect to the variable of interest. CONCLUSIONS: Within the BCI forest dynamics plot, distributions of some plant taxa are associated with local-scale differences in soil variables when evaluated at individual nodes within the phylogenetic tree, but they are not detectable by phylogeny-wide signal. Trends highlighted in this analysis suggest how plant-soil associations may drive plant distributions and diversity at the local-scale.

  6. Wildfire Dynamics and Occasional Precipitation during Active Fire Season in Tropical Lowland of Nepal

    Directory of Open Access Journals (Sweden)

    Krishna Bahadur Bhujel

    2017-10-01

    Full Text Available Occasional precipitation plays a vital role in reducing the effect of wildfire. This precipitation is especially important for countries like Nepal, where wildfires are a common seasonal event. Approximately 0.1 million hectare of forest area is affected annually due to wildfires in active fire season. The study on the relation of these forms of occasional precipitation with wildfire incidence is still lacking. This research was objectively carried out to examine the correlation of occasional precipitation with wildfire incidence and burnt area. The Moderate Resolution Imaging Spector-Radiometer (MODIS satellite images and precipitation records for 15 years gathered from Department of Hydrology and Metrology were used as input data for this study. The images were analyzed by using ArcGIS function while the precipitation records were analyzed by using Statistical Package for the Social Science (SPSS program. The linear regression model was applied to find correlation of occasional precipitation with wildfire incidence and burnt area. Analysis revealed decreasing trend of precipitation in study area. We found significant correlation (p<0.05 of precipitation with wildfire incidence and burnt area. Findings will be useful for policy makers, implementers and researchers to manage wildfire in sustainable basis.

  7. Performance of Minneola tangelo trees grafted over six rootstocks in Colombia Tropical Lowland (1997-2010

    Directory of Open Access Journals (Sweden)

    Hans Chaparro

    2017-07-01

    Full Text Available ‘Cleopatra’ tangerine (Citrus reshni hort. ex Tanaka is a commonly used rootstock in the piedmont of Meta department, Colombia for establishing of commercial citrus orchards. Have allowed a late production entrance rootstock and produced big plants when grafted with tangelo ‘Minneola’ (C. reticulata Blanco x C. paradise Macf, decreasing the productive efficiency in plants and hard crop practices. The evaluated performance were as follows:  tree size, productive efficiency and fruit quality of tangelo ‘Minneola’ grafted in six rootstocks. It found that the cumulated production of 11 years was better with Citrumelo ‘Swingle’ (Citrus paradisi Macf. × Poncirus trifoliata (L. Raf with 1388.3 kg tree-1, followed by ‘Cleopatra’ (Citrus reshni hort. ex Tanaka with 893.2 kg.tree-1, in last place was ‘Carrizo’ (Citrus sinensis Osb. × Poncirustrifoliata (L. Raf with 182.9 kg tree-1. The other rootstocks, had a medium production. The greatest height and canopy value, was found with ‘Cleopatra’ without significant differences with Citrumelo ‘Swingle’. In fruit quality no significant differences occurred.

  8. Integrated crop management of hot pepper (Capsicum spp.) in tropical lowlands

    NARCIS (Netherlands)

    Vos, J.G.M.

    1994-01-01

    Hot pepper ( Capsicum spp.) is the most important low elevation vegetable commodity in Indonesia. Yields are low, in part due to crop health problems. Farmers' practices were surveyed by means of exploratory surveys. Hot pepper pests and diseases were identified and

  9. The influence of sea-level changes on tropical coastal lowlands; the Pleistocene Coropina Formation, Suriname

    Science.gov (United States)

    Wong, Th. E.; de Kramer, R.; de Boer, P. L.; Langereis, C.; Sew-A-Tjon, J.

    2009-04-01

    The Pleistocene Coropina Formation largely constitutes the Old Coastal Plain of Suriname. It is exposed fully only in open-pit bauxite mines in the central coastal plain as part of the unconsolidated overburden of Paleocene-Eocene bauxites. This study deals with the stratigraphy, sedimentology and chronology of this formation, and is based on a study in the recently closed Lelydorp-III bauxite mine operated by N.V. BHP Billiton Maatschappij Suriname. The Coropina Formation consists of the Para and Lelydorp Members. We present a detailed lithological subdivision of these members. In the Para Member, four units are discerned which are grouped in two transgressive cycles, both ranging upward from terrestrial towards chenier and coastal mudflat deposits reflecting glacio-eustatic sea-level changes. The sandy sediments represent fluviatile and beach-bar (chenier) deposits, and were supplied by rivers from the Precambrian basement and to a lesser extent by westward longshore coastal drift. Clays, largely derived from the Amazon River and transported alongshore over the shelf, were deposited in extensive coastal mudflats. The Lelydorp Member, also comprising four units, represents a depositional system that is closely comparable to the recent Suriname coastal setting, i.e., a lateral and vertical alternation of mudflat and chenier deposits formed over a period characterised by more or less constant sea level. Palaeomagnetic data indicate a dominantly reversed magnetic polarity in the Para Member, whereas the Lelydorp Member shows a normal magnetic polarity with a minor reversed polarity overprint. The reversed polarities of the Para Member exclude a Brunhes Chron (0.78-0.0 Ma) age, and thus assign it to the Matuyama Chron (2.58-0.78 Ma). This implies that the Coropina Formation is much older than hitherto assumed, and that one or more (long-term) hiatuses are not recognizable in the lithological succession.

  10. Stemflow Variability in Tropical Lowland Forest Landscape Transformation System: Case Study at Jambi Province, Indonesia

    Directory of Open Access Journals (Sweden)

    Bejo Slamet

    2015-06-01

    Full Text Available Land cover change may cause change on the hydrological function of an area, particularly on the distribution of rainfall that reach land surface. This study describes the characteristic of stemflow occurred within 4 ecosystems in Jambi, namely logged forest, jungle rubber, rubber plantation, and oil palm plantation. The main objective of the study was to measure the variability of stemflow in those 4 ecosystems. The main data used were rainfall and stemflow data that were directly measured for 5 months. The derived regression equation model showed that stemflow increase with rainfall depth. It was shown that values of stemflow amongs plantation types was varied indicated by the difference of its regression coefficients, as well as variations of the rainfall at the same transformation type. The percentage of stemflow to rainfall was ranging from 0.04–0.21% for rubber, 0.10–0.38% for jungle rubber, 0.28–0.54% for forest, and 0.84–3.07% for oil palm. The oil palm provided the highest stemflow volume compared to other land cover type. The uniqueness of oil palm canopy may cause the drainage of water from the canopy to the main stem that indicated by highest stemflow funneling ratio value. Rainfall significantly affected the amount of stemflow compared with the characteristics of the plant. Keywords: forest transformation, land cover change, stemflow variability, stemflow funnelling ratio

  11. Dry gas vents (“mazuku”) in Goma region (North-Kivu, Democratic Republic of Congo): Formation and risk assessment

    Science.gov (United States)

    Smets, Benoît; Tedesco, Dario; Kervyn, François; Kies, Antoine; Vaselli, Orlando; Yalire, Mathieu Mapendano

    2010-12-01

    The word " mazuku" in Swahili means "evil wind". It corresponds to lowland (depressions) where carbon dioxide is released and, being heavier than air, accumulates at high - often lethal - concentrations (10 vol.% of CO 2 in atmosphere can be considered as the deadly threshold, even for a short time exposure). Mazuku are abundant in Goma and surrounding areas and particularly in the area south of the large volcanic edifices of Nyiragongo and Nyamulagira volcanoes located in the most eastern part of DR Congo, W branch of the East African Rift System (EARS). Our extensive field surveys have indicated that mazuku are concentrated within to and around the densely populated city of Goma close to the N shores of Lake Kivu, mainly near fault or fissure networks. At a more local scale, depressions allowing CO 2-rich gas accumulation are created by lava flow superposition, lava tunnels or cavity collapses, or directly associated with open fractures. People are killed by mazuku every year. Given political and social unrest coupled with the current important demographic and urban growths around Goma, the risks associated to mazuku are increasing accordingly. Mazuku are currently the most important natural risk in terms of human loss for the area and there is an urgent need for further research, more systematic mapping and monitoring of mazuku and for appropriate risk management to be implemented. This paper summarizes the current scientific knowledge on mazuku as well as new advances and a preliminary risk assessment performed recently in the frame of the GORISK project.

  12. National forest cover change in Congo Basin: deforestation, reforestation, degradation and regeneration for the years 1990, 2000 and 2005.

    Science.gov (United States)

    Céline, Ernst; Philippe, Mayaux; Astrid, Verhegghen; Catherine, Bodart; Musampa, Christophe; Pierre, Defourny

    2013-04-01

    This research refers to an object-based automatic method combined with a national expert validation to produce regional and national forest cover change statistics over Congo Basin. A total of 547 sampling sites systematically distributed over the whole humid forest domain are required to cover the six Central African countries containing tropical moist forest. High resolution imagery is used to accurately estimate not only deforestation and reforestation but also degradation and regeneration. The overall method consists of four steps: (i) image automatic preprocessing and preinterpretation, (ii) interpretation by national expert, (iii) statistic computation and (iv) accuracy assessment. The annual rate of net deforestation in Congo Basin is estimated to 0.09% between 1990 and 2000 and of net degradation to 0.05%. Between 2000 and 2005, this unique exercise estimates annual net deforestation to 0.17% and annual net degradation to 0.09%. An accuracy assessment reveals that 92.7% of tree cover (TC) classes agree with independent expert interpretation. In the discussion, we underline the direct causes and the drivers of deforestation. Population density, small-scale agriculture, fuelwood collection and forest's accessibility are closely linked to deforestation, whereas timber extraction has no major impact on the reduction in the canopy cover. The analysis also shows the efficiency of protected areas to reduce deforestation. These results are expected to contribute to the discussion on the reduction in CO2 emissions from deforestation and forest degradation (REDD+) and serve as reference for the period. © 2012 Blackwell Publishing Ltd.

  13. On interception modelling of a lowland coastal rainforest in northern Queensland, Australia

    Science.gov (United States)

    Wallace, Jim; McJannet, Dave

    2006-10-01

    SummaryRecent studies of the water balance of tropical rainforests in northern Queensland have revealed that large fractions of rainfall, up to 30%, are intercepted by the canopy and lost as evaporation. These loss rates are much higher than those reported for continental rainforests, for example, in the Amazon basin, where interception is around 9% of rainfall. Higher interception losses have been found in coastal and mountain rainforests and substantial advection of energy during rainfall is proposed to account for these results. This paper uses a process based model of interception to analyse the interception losses at Oliver Creek, a lowland coastal rainforest site in northern Queensland with a mean annual rainfall of 3952 mm. The observed interception loss of 25% of rainfall for the period August 2001 to January 2004 can be reproduced by the model with a suitable choice of the three key controlling variables, the canopy storage capacity, mean rainfall rate and mean wet canopy evaporation rate. Our analyses suggest that the canopy storage capacity of the Oliver Creek rainforest is between 3.0 and 3.5 mm, higher than reported for most other rainforests. Despite the high canopy capacity at our site, the interception losses can only be accounted for with energy advection during rainfall in the range 40-70% of the incident energy.

  14. Coupled Socio-Ecological Drivers of Carbon Storage in South African Coastal Lowland Landscapes

    Science.gov (United States)

    Smithwick, E. A.

    2011-12-01

    The amount of carbon stored in African terrestrial ecosystems is unknown, varying from 30 to >250 Mg C ha-1 in tropical forests. Several prominent efforts are improving this estimate through forest inventories and modeling, but carbon storage varies across ecosystems and some ecosystems remain vastly understudied. This is critical given that Africa's net carbon flux ranges from a source to a substantial carbon sink, making it one of the weakest links in the global carbon cycle. One such understudied ecosystem is the coastal lowland forest along the Eastern Cape of South Africa, which lies between two internationally recognized biodiversity hotspots and is a current focus of conservation efforts in the region. Six permanent forest plots were established within two nature reserves during February 2011. Using empirical wood density estimates, aboveground tree carbon was estimated using established allometric equations. Results indicated that forests store between 50 and 100 Mg C ha-1, with significant variability among sites. However, the landscapes of the nature reserves differ significantly in the amount of forest cover due to differences in fire frequencies (ranging from 100 years), which are largely determined by rates of wildlife poaching within nature reserves. Thus, although estimates of forest carbon storage are heterogeneous within Eastern Cape forests, landscape-scale carbon storage is governed largely by human activities and reflects strongly coupled socio-ecological drivers. Estimates of landscape-scale carbon storage can help guide conservation management strategies and form the basis of future modeling efforts exploring interactions of climate, disturbance, and human livelihoods.

  15. Hydroclimate changes across the Amazon lowlands over the past 45,000 years

    Science.gov (United States)

    Wang, Xianfeng; Edwards, R. Lawrence; Auler, Augusto S.; Cheng, Hai; Kong, Xinggong; Wang, Yongjin; Cruz, Francisco W.; Dorale, Jeffrey A.; Chiang, Hong-Wei

    2017-01-01

    Reconstructing the history of tropical hydroclimates has been difficult, particularly for the Amazon basin—one of Earth’s major centres of deep atmospheric convection. For example, whether the Amazon basin was substantially drier or remained wet during glacial times has been controversial, largely because most study sites have been located on the periphery of the basin, and because interpretations can be complicated by sediment preservation, uncertainties in chronology, and topographical setting. Here we show that rainfall in the basin responds closely to changes in glacial boundary conditions in terms of temperature and atmospheric concentrations of carbon dioxide. Our results are based on a decadally resolved, uranium/thorium-dated, oxygen isotopic record for much of the past 45,000 years, obtained using speleothems from Paraíso Cave in eastern Amazonia; we interpret the record as being broadly related to precipitation. Relative to modern levels, precipitation in the region was about 58% during the Last Glacial Maximum (around 21,000 years ago) and 142% during the mid-Holocene epoch (about 6,000 years ago). We find that, as compared with cave records from the western edge of the lowlands, the Amazon was widely drier during the last glacial period, with much less recycling of water and probably reduced plant transpiration, although the rainforest persisted throughout this time.

  16. Flow controls on lowland river macrophytes: a review.

    Science.gov (United States)

    Franklin, Paul; Dunbar, Michael; Whitehead, Paul

    2008-08-01

    We review the current status of knowledge regarding the role that flow parameters play in controlling the macrophyte communities of temperate lowland rivers. We consider both direct and indirect effects and the interaction with other factors known to control macrophyte communities. Knowledge gaps are identified and implications for the management of river systems considered. The main factors and processes controlling the status of macrophytes in lowland rivers are velocity (hence also discharge), light, substrate, competition, nutrient status and river management practices. We suggest that whilst the characteristics of any particular macrophyte community reflect the integral effects of a combination of the factors, fundamental importance can be attributed to the role of discharge and velocity in controlling instream macrophyte colonisation, establishment and persistence. Velocity and discharge also appear to control the relative influence of some of the other controlling factors. Despite the apparent importance of velocity in determining the status of macrophyte communities in lowland rivers, relatively little is understood about the nature of the processes controlling this relationship. Quantitative knowledge is particularly lacking. Consequently, the ability to predict macrophyte abundance and distribution in rivers is still limited. This is further complicated by the likely existence of feedback effects between the growth of macrophytes and velocity. Demand for water resources increases the pressure on lowland aquatic ecosystems. Despite growing recognition of the need to allocate water for the needs of instream biota, the inability to assess the flow requirements of macrophyte communities limits the scope to achieve this. This increases the likelihood of overexploitation of the water resource as other users, whose demands are quantifiable, are prioritised.

  17. A water storage adaptation in the maya lowlands.

    Science.gov (United States)

    Scarborough, V L; Gallopin, G G

    1991-02-08

    Prehispanic water management in the Maya Lowlands emphasized collection and storage rather than the canalization and diversion accentuated in highland Mexico. Reexamination of site maps of the ancient Maya city of Tikal, Guatemala, has revealed an important, overlooked factor in Maya centralization and urban settlement organization. In a geographical zone affected by an extended dry season and away from permanent water sources, large, well-planned reservoirs provided resource control as well as political leverage.

  18. Land Resources in Lowland of Kosova and Their Utilization

    OpenAIRE

    , S. Bulliqi; , F. Isufi; , F. Humolli; , A. Stublla; , E. Stublla

    2012-01-01

    The land presents a specific natural-historical body, respectively the rake surface of the earth as a result of effects from joint pathogenesis factors (climate, water, vegetation, relief and time). The spreading and use of land in the territory of the Republic of Kosova is not equal, therefore a research for the use of land in the Lowland of Kosova is very important, especially urbanism because of the concentration of population and uncontrolled development of. The general surface of the lan...

  19. Adaptations of lowland jungle mosses to anthropogenic environments in Guyana

    OpenAIRE

    Kuc, Marian

    2000-01-01

    Sixteen lowland jungle mosses growing in anthropogenic habitats at Santa and The Bell - Ituni localities on the Demerara River in Guyana were examined in detail with the aim of detecting any features which would indicate their adaptations to new habitats. Amounts of chlorophyll in leaf cells, protective coloration, alterations in leaf morphology, characteristics of old stems, rhizoid tomentum and fertility are considered as the most pronounced adaptive features of these species to new localit...

  20. Lowland tapir distribution and habitat loss in South America

    Directory of Open Access Journals (Sweden)

    Jose Luis Passos Cordeiro

    2016-09-01

    Full Text Available The development of species distribution models (SDMs can help conservation efforts by generating potential distributions and identifying areas of high environmental suitability for protection. Our study presents a distribution and habitat map for lowland tapir in South America. We also describe the potential habitat suitability of various geographical regions and habitat loss, inside and outside of protected areas network. Two different SDM approaches, MAXENT and ENFA, produced relative different Habitat Suitability Maps for the lowland tapir. While MAXENT was efficient at identifying areas as suitable or unsuitable, it was less efficient (when compared to the results by ENFA at identifying the gradient of habitat suitability. MAXENT is a more multifaceted technique that establishes more complex relationships between dependent and independent variables. Our results demonstrate that for at least one species, the lowland tapir, the use of a simple consensual approach (average of ENFA and MAXENT models outputs better reflected its current distribution patterns. The Brazilian ecoregions have the highest habitat loss for the tapir. Cerrado and Atlantic Forest account for nearly half (48.19% of the total area lost. The Amazon region contains the largest area under protection, and the most extensive remaining habitat for the tapir, but also showed high levels of habitat loss outside protected areas, which increases the importance of support for proper management.

  1. Lowland tapir distribution and habitat loss in South America.

    Science.gov (United States)

    Cordeiro, Jose Luis Passos; Fragoso, José M V; Crawshaw, Danielle; Oliveira, Luiz Flamarion B

    2016-01-01

    The development of species distribution models (SDMs) can help conservation efforts by generating potential distributions and identifying areas of high environmental suitability for protection. Our study presents a distribution and habitat map for lowland tapir in South America. We also describe the potential habitat suitability of various geographical regions and habitat loss, inside and outside of protected areas network. Two different SDM approaches, MAXENT and ENFA, produced relative different Habitat Suitability Maps for the lowland tapir. While MAXENT was efficient at identifying areas as suitable or unsuitable, it was less efficient (when compared to the results by ENFA) at identifying the gradient of habitat suitability. MAXENT is a more multifaceted technique that establishes more complex relationships between dependent and independent variables. Our results demonstrate that for at least one species, the lowland tapir, the use of a simple consensual approach (average of ENFA and MAXENT models outputs) better reflected its current distribution patterns. The Brazilian ecoregions have the highest habitat loss for the tapir. Cerrado and Atlantic Forest account for nearly half (48.19%) of the total area lost. The Amazon region contains the largest area under protection, and the most extensive remaining habitat for the tapir, but also showed high levels of habitat loss outside protected areas, which increases the importance of support for proper management.

  2. D3.2 The DR. Congo review

    DEFF Research Database (Denmark)

    Mandrup, Thomas

    2017-01-01

    , representatives of the Congolese authorities, NGOs and other IOs. EU involvement started with the deployment of Artemis in 2003, and the study ends with the closure of EUSEC in July 2016. All EU missions in the Democratic Republic of Congo (DRC) have been part of EU support for the transition and implementation...

  3. Climate Change Impacts on the Congo Basin Region

    NARCIS (Netherlands)

    Ludwig, F.; Franssen, W.; Jans, W.W.P.; Kruijt, B.; Supit, I.

    2012-01-01

    This report presents analyses of climate change impacts in the Congo Basin on water for agriculture and hydropower, forest ecosystem functioning and carbon storage and impacts of climate variability and change on future economic development. To quantify the impacts of future climate we developed a

  4. Crimean-Congo Hemorrhagic Fever Virus in Bulgaria and Turkey

    Czech Academy of Sciences Publication Activity Database

    Mertens, M.; Schuster, I.; Sas, M. A.; Vatansever, Z.; Hubálek, Zdeněk; Güven, E.; Deniz, A.; Georgiev, G.; Peshev, R.; Groschup, M. H.

    2016-01-01

    Roč. 16, č. 9 (2016), s. 619-623 ISSN 1530-3667 EU Projects: European Commission(XE) 261504 - EDENEXT Institutional support: RVO:68081766 Keywords : Crimean-Congo hemorrhagic fever virus: CCHFV * domestic animals * ELISA * epidemiology Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 2.045, year: 2016

  5. The deforestation of rural areas in the Lower Congo Province.

    Science.gov (United States)

    Iloweka, Ernest Manganda

    2004-12-01

    The Lower Congo is one of eleven provinces in the Democratic Republic of Congo, and is located southwest of Kinshasa Town Province. It has an area of approximately 53.947 km2 with a population of 1,504,361 at an estimated 237 persons per km2. The Province comprises five districts, including Lukaya and Cataracts where rural poverty is severe and the population struggle to make a living through agriculture and woodcutting. These activities result in excessive resource exploitation. The high demand for foodstuffs and the high consumption of wood (for energy, construction and export) in Kinshasa, the capital city of the Democratic Republic of Congo and the expanding towns of Matadi and Boma in the Lower Congo Province, are speeding the deforestation rate and unbalancing forest ecosystems. In addition there is the stress resulting from reduced josher (the rest period for agriculture ground), plus climate change and erosion. The phenomena that that we need to address in these two districts include deforestation, reduced josher, excessive agriculture, erosion, burning and climate change which taken together largely explain the current soil degradation. These areas are marked by excessive post deforestation savannah formation and extended areas of sandy soil, distributed throughout grass and shrub savannahs. This desertification, which is rampant in Lukaya and Cataracts, risks imprisoning the rural population in a vicious cycle of poverty if adequate solutions are not found.

  6. Physiological and biochemical responses of Chlorella vulgaris to Congo red.

    Science.gov (United States)

    Hernández-Zamora, Miriam; Perales-Vela, Hugo Virgilio; Flores-Ortíz, César Mateo; Cañizares-Villanueva, Rosa Olivia

    2014-10-01

    Extensive use of synthetic dyes in many industrial applications releases large volumes of wastewater. Wastewaters from dying industries are considered hazardous and require careful treatment prior to discharge into receiving water bodies. Dyes can affect photosynthetic activities of aquatic flora and decrease dissolved oxygen in water. The aim of this study was to evaluate the effect of Congo red on growth and metabolic activity of Chlorella vulgaris after 96h exposure. Exposure of the microalga to Congo red reduced growth rate, photosynthesis and respiration. Analysis of chlorophyll a fluorescence emission showed that the donor side of photosystem II was affected at high concentrations of Congo red. The quantum yield for electron transport (φEo), the electron transport rate (ETR) and the performance index (PI) also decreased. The reduction in the ability to absorb and use the quantum energy increased non-photochemical (NPQ) mechanisms for thermal dissipation. Overall, Congo red affects growth and metabolic activity in photosynthetic organisms in aquatic environments. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Evaluation of patients with Crimean-Congo hemorrhagic fever in ...

    African Journals Online (AJOL)

    Background: Crimean-Congo hemorrhagic fever (CCHF), which is associated with a high mortality rate in the Black Sea region of Turkey, has received increasing attention. Objective: In this study, the epidemiological features, clinical and laboratory findings, treatments, and outcomes of patients diagnosed with CCHF ...

  8. Crimean-Congo Hemorrhagic Fever, Kazakhstan, 2009–2010

    Science.gov (United States)

    Knust, Barbara; Medetov, Zhumagul B.; Kyraubayev, Kakimzhan B.; Bumburidi, Yekaterina; Erickson, Bobbie Rae; MacNeil, Adam; Bayserkin, Baurzhan S.; Ospanov, Kenes S.

    2012-01-01

    We evaluated Crimean-Congo hemorrhagic fever (CCHF) surveillance data from southern Kazakhstan during 2009–2010 and found both spatial and temporal association between reported tick bites and CCHF cases. Public health measures should center on preventing tick bites, increasing awareness of CCHF signs and symptoms, and adopting hospital infection control practices. PMID:22469505

  9. Changing governance arrangements: NTFP value chains in the Congo Basin

    NARCIS (Netherlands)

    Ingram, V.J.

    2017-01-01

    As forest products from Cameroon and DR Congo are commercialised, a value chain is created from harvesters, processors, and retailers to
    consumers worldwide. In contrast to dominant narratives focusing on regulations and customs, these chains are actually governed by dynamic,
    multiple

  10. Risk Assessment: Democratic Republic of Congo Post-Laurent ...

    African Journals Online (AJOL)

    political system as opposed to the view that it was merely a power struggle between Kabila on the .... Local actors and international mining companies built alliances exploiting Congo's minerals to gain a ... They are preparing a contingency plan for their activities in the post-Laurent Kabila era, for ... small arms in the DRC.33.

  11. Phonology and Morphology of Mambay (Niger-Congo, Adamawa)

    NARCIS (Netherlands)

    Anonby, Erik John

    2008-01-01

    Mambay is an Adamawa (Niger-Congo) language spoken by 15,000 people in Chad and Cameroon. The study opens with historical and linguistic background. A phonological inventory of the language is then presented and distribution patterns are examined. Some striking phenomena include a profoundly

  12. Sorption behavior of congo red on different plant leaves (abstract)

    International Nuclear Information System (INIS)

    Khan, M.I.; Mirza, M.L.; Zafar, S.; Khalid, N.

    2011-01-01

    Batch adsorption studies were carried out to evaluate the potential of different plant leaves (Bougainvillaea Glabra and Citrus Sinensis) for the removal of Congo red dye from aqueous solution by optimizing different parameters such as effect of shaking time, adsorbent dose, initial adsorbate concentration, temperature etc. The experimental data was subjected to different types of isotherm models such as Freundlich, Langmuir and Dubinin-Radushkevich. The maximum adsorption capacity was calculated and was comparable for both the leaves through Freundlich isotherm by using the optimized parameters of weight and time at room temperature. The sorption mean free energy from Dubinin-Radushkevich isotherm was also determined and compared. Pseudo-first and Pseudo-second order kinetics models were tested for the adsorption of Congo red on plant leaves powder. The experimental data fitted well for Pseudo-second order model. The uptake of Congo red was also studied with the variation of temperature. Thermodynamic parameters have been calculated. The results indicate that the plant leaves of Bougainvilia Glabra and Citrus Sinensis are efficient adsorbents for Congo red dye from aqueous solutions and can be used for wastewater management. (author)

  13. Opportunities for Hydrologic Research in the Congo Basin

    Science.gov (United States)

    Alsdorf, D. E.; Beighley, E., II; Lee, H.; Tshimanga, R.; Spencer, R. G.; O'Loughlin, F.

    2014-12-01

    We review the published results on the Congo Basin hydrology and find that there are historic data, ongoing measurement recording efforts, and important model results. Annual rainfall is ~2000 mm/yr along an east-west trend, decreasing northward and southward to ~1100 mm/yr. While some studies show rain gauges at specific locations with declines in P greater than 10% from 1960 to 1990, other studies suggest that basin wide decreases from 1951 to 1993 are modest at 4.5% or that the trend is minimal. Studies during the 1950s using lysimeters, pans, and models suggest that the annual potential ET varies little across the basin at a 1100 mm/yr to 1200 mm/yr. Over the past century, river discharge data has been collected at 100s of stream gauges with historic and recent data at 96 locations now publicly available. Discharge of the Congo River at Kinshasa-Brazzaville experienced an increase of 21% during 1960-1970 in comparison to background values of the previous decades and of today. There does not appear to be a long-term discharge trend over the century of record. Satellite altimetry measurements collected during high and low flows show that the Cuvette Centrale wetland water levels are consistently 0.5m to 3m higher in elevation than the immediately adjacent Congo River levels. Wetland water depths are shallow at about 1m whereas the Congo is typically less than 15m deep everywhere upstream of Kinshasa. The wetlands do not appear to be marked by sizable channels such that the flows are diffusive. CO2 and CH4 evasion from the Congo waters directly to the atmosphere are estimated at 1.6 to 3.2 Tg/yr for CH4 from the Cuvette wetland waters and 105 to 204 g C/m2/yr for CO2 from waters of the Oubangui River. Using these published results, we suggest seven hypotheses that may lead to important water and carbon cycle discoveries. These hypotheses focus on the source of the Cuvette waters and how those waters leave the wetland; on river discharge generated by historic

  14. Vegetation dynamics of the Guatemalan lowlands from MIS7 to MIS5: Evidence from Lake Petén-Itzá

    Science.gov (United States)

    Cruz-Silva, E.; Correa-Metrio, A.; Bush, M. B.

    2013-05-01

    Reconstructing vegetation patterns of past warm climatic stages is critical for understanding modern processes that affect diversity and climate. Tropical lowlands are of special interest because of the high biodiversity they foster and the risks they face under a scenario of rapid climate change. With a basal age of more that 191,000 years, core PI-1 from Lake Petén-Itzá, Guatemalan lowlands, offer an exceptional opportunity to investigate the dynamics of the vegetation of the area during climatic stages that might be analogous to today. Pollen analysis of the lower part of this sedimentary record shows a sequence of five different climatic stages of alternating warm and cold conditions. According to our interpretation, tropical forests extended in the area during MIS7 and MIS5, with the former characterized by drier conditions than the latter. Apparently forest dynamics closely followed global climatic changes that were recorded in the Antarctic and the Marine Stack records. Our results confirm that vegetation of the Peninsula, although highly resilient, has been very sensitive to global climatic changes.

  15. Characterising groundwater-dominated lowland catchments: the UK Lowland Catchment Research Programme (LOCAR

    Directory of Open Access Journals (Sweden)

    2007-01-01

    Full Text Available This paper reports on a major UK initiative to address deficiencies in understanding the hydro-ecological response of groundwater-dominated lowland catchments. The scope and objectives of this national programme are introduced and focus on one of three sets of research basins – the Pang/Lambourn Chalk catchments, tributaries of the river Thames in southern England. The motivation for the research is the need to support integrated management of river systems that have high ecological value and are subject to pressures that include groundwater abstraction for water supply, diffuse pollution, and land use and climate change. An overview of the research programme is provided together with highlights of some current research findings concerning the hydrological functioning of these catchments. Despite the importance of the Chalk as a major UK aquifer, knowledge of the subsurface movement of water and solutes is poor. Solute transport in the dual porosity unsaturated zone depends on fracture/matrix interactions that are difficult to observe; current experimental and modelling research supports the predominance of matrix flow and suggests that slow migration of a time-history of decades of nutrient loading is occurring. Groundwater flows are complex; catchments vary seasonally and are ill-defined and karst features are locally important. Groundwater flow pathways are being investigated using natural and artificial geochemical tracers based on experimental borehole arrays; stream-aquifer interaction research is using a combination of geophysics, borehole array geochemistry and longitudinal profiles of stream flow and solutes. A complex picture of localised subsurface inflows, linked to geological controls and karst features, and significant longitudinal groundwater flow below the river channel is emerging. Management implications are discussed. Strategies to control surface application of nutrients are expected to have little effect on groundwater

  16. Pervasive phosphorus limitation of tree species but not communities in tropical forests

    Science.gov (United States)

    Turner, Benjamin L.; Brenes-Arguedas, Tania; Condit, Richard

    2018-03-01

    Phosphorus availability is widely assumed to limit primary productivity in tropical forests, but support for this paradigm is equivocal. Although biogeochemical theory predicts that phosphorus limitation should be prevalent on old, strongly weathered soils, experimental manipulations have failed to detect a consistent response to phosphorus addition in species-rich lowland tropical forests. Here we show, by quantifying the growth of 541 tropical tree species across a steep natural phosphorus gradient in Panama, that phosphorus limitation is widespread at the level of individual species and strengthens markedly below a threshold of two parts per million exchangeable soil phosphate. However, this pervasive species-specific phosphorus limitation does not translate into a community-wide response, because some species grow rapidly on infertile soils despite extremely low phosphorus availability. These results redefine our understanding of nutrient limitation in diverse plant communities and have important implications for attempts to predict the response of tropical forests to environmental change.

  17. Why tropical forest lizards are vulnerable to climate warming

    Science.gov (United States)

    Huey, Raymond B.; Deutsch, Curtis A.; Tewksbury, Joshua J.; Vitt, Laurie J.; Hertz, Paul E.; Álvarez Pérez, Héctor J.; Garland, Theodore

    2009-01-01

    Biological impacts of climate warming are predicted to increase with latitude, paralleling increases in warming. However, the magnitude of impacts depends not only on the degree of warming but also on the number of species at risk, their physiological sensitivity to warming and their options for behavioural and physiological compensation. Lizards are useful for evaluating risks of warming because their thermal biology is well studied. We conducted macrophysiological analyses of diurnal lizards from diverse latitudes plus focal species analyses of Puerto Rican Anolis and Sphaerodactyus. Although tropical lowland lizards live in environments that are warm all year, macrophysiological analyses indicate that some tropical lineages (thermoconformers that live in forests) are active at low body temperature and are intolerant of warm temperatures. Focal species analyses show that some tropical forest lizards were already experiencing stressful body temperatures in summer when studied several decades ago. Simulations suggest that warming will not only further depress their physiological performance in summer, but will also enable warm-adapted, open-habitat competitors and predators to invade forests. Forest lizards are key components of tropical ecosystems, but appear vulnerable to the cascading physiological and ecological effects of climate warming, even though rates of tropical warming may be relatively low. PMID:19324762

  18. Unsustainable development pathways caused by tropical deforestation.

    Science.gov (United States)

    Carrasco, Luis Roman; Nghiem, Thi Phuong Le; Chen, Zhirong; Barbier, Edward B

    2017-07-01

    Global sustainability strategies require assessing whether countries' development trajectories are sustainable over time. However, sustainability assessments are limited because losses of natural capital and its ecosystem services through deforestation have not been comprehensively incorporated into national accounts. We update the national accounts of 80 nations that underwent tropical deforestation from 2000 to 2012 and evaluate their development trajectories using weak and strong sustainability criteria. Weak sustainability requires that countries do not decrease their aggregate capital over time. We adopt a strong sustainability criterion that countries do not decrease the value of their forest ecosystem services with respect to the year 2000. We identify several groups of countries: countries, such as Sri Lanka, Bangladesh, and India, that present sustainable development trajectories under both weak and strong sustainability criteria; countries, such as Brazil, Peru, and Indonesia, that present weak sustainable development but fail the strong sustainability criterion as a result of rapid losses of ecosystem services; countries, such as Madagascar, Laos, and Papua New Guinea, that present unsustainable development pathways as a result of deforestation; and countries, such as Democratic Republic of Congo and Sierra Leone, in which deforestation aggravates already unsustainable pathways. Our results reveal a large number of countries where tropical deforestation is both damaging to nature and not compensated by development in other sectors, thus compromising the well-being of their future generations.

  19. Combining satellite, aerial and ground measurements to assess forest carbon stocks in Democratic Republic of Congo

    Science.gov (United States)

    Beaumont, Benjamin; Bouvy, Alban; Stephenne, Nathalie; Mathoux, Pierre; Bastin, Jean-François; Baudot, Yves; Akkermans, Tom

    2015-04-01

    Monitoring tropical forest carbon stocks changes has been a rising topic in the recent years as a result of REDD+ mechanisms negotiations. Such monitoring will be mandatory for each project/country willing to benefit from these financial incentives in the future. Aerial and satellite remote sensing technologies offer cost advantages in implementing large scale forest inventories. Despite the recent progress made in the use of airborne LiDAR for carbon stocks estimation, no widely operational and cost effective method has yet been delivered for central Africa forest monitoring. Within the Maï Ndombe region of Democratic Republic of Congo, the EO4REDD project develops a method combining satellite, aerial and ground measurements. This combination is done in three steps: [1] mapping and quantifying forest cover changes using an object-based semi-automatic change detection (deforestation and forest degradation) methodology based on very high resolution satellite imagery (RapidEye), [2] developing an allometric linear model for above ground biomass measurements based on dendrometric parameters (tree crown areas and heights) extracted from airborne stereoscopic image pairs and calibrated using ground measurements of individual trees on a data set of 18 one hectare plots and [3] relating these two products to assess carbon stocks changes at a regional scale. Given the high accuracies obtained in [1] (> 80% for deforestation and 77% for forest degradation) and the suitable, but still to be improved with a larger calibrating sample, model (R² of 0.7) obtained in [2], EO4REDD products can be seen as a valid and replicable option for carbon stocks monitoring in tropical forests. Further improvements are planned to strengthen the cost effectiveness value and the REDD+ suitability in the second phase of EO4REDD. This second phase will include [A] specific model developments per forest type; [B] measurements of afforestation, reforestation and natural regeneration processes and

  20. Evolution of endemism on a young tropical mountain.

    Science.gov (United States)

    Merckx, Vincent S F T; Hendriks, Kasper P; Beentjes, Kevin K; Mennes, Constantijn B; Becking, Leontine E; Peijnenburg, Katja T C A; Afendy, Aqilah; Arumugam, Nivaarani; de Boer, Hugo; Biun, Alim; Buang, Matsain M; Chen, Ping-Ping; Chung, Arthur Y C; Dow, Rory; Feijen, Frida A A; Feijen, Hans; Feijen-van Soest, Cobi; Geml, József; Geurts, René; Gravendeel, Barbara; Hovenkamp, Peter; Imbun, Paul; Ipor, Isa; Janssens, Steven B; Jocqué, Merlijn; Kappes, Heike; Khoo, Eyen; Koomen, Peter; Lens, Frederic; Majapun, Richard J; Morgado, Luis N; Neupane, Suman; Nieser, Nico; Pereira, Joan T; Rahman, Homathevi; Sabran, Suzana; Sawang, Anati; Schwallier, Rachel M; Shim, Phyau-Soon; Smit, Harry; Sol, Nicolien; Spait, Maipul; Stech, Michael; Stokvis, Frank; Sugau, John B; Suleiman, Monica; Sumail, Sukaibin; Thomas, Daniel C; van Tol, Jan; Tuh, Fred Y Y; Yahya, Bakhtiar E; Nais, Jamili; Repin, Rimi; Lakim, Maklarin; Schilthuizen, Menno

    2015-08-20

    Tropical mountains are hot spots of biodiversity and endemism, but the evolutionary origins of their unique biotas are poorly understood. In varying degrees, local and regional extinction, long-distance colonization, and local recruitment may all contribute to the exceptional character of these communities. Also, it is debated whether mountain endemics mostly originate from local lowland taxa, or from lineages that reach the mountain by long-range dispersal from cool localities elsewhere. Here we investigate the evolutionary routes to endemism by sampling an entire tropical mountain biota on the 4,095-metre-high Mount Kinabalu in Sabah, East Malaysia. We discover that most of its unique biodiversity is younger than the mountain itself (6 million years), and comprises a mix of immigrant pre-adapted lineages and descendants from local lowland ancestors, although substantial shifts from lower to higher vegetation zones in this latter group were rare. These insights could improve forecasts of the likelihood of extinction and 'evolutionary rescue' in montane biodiversity hot spots under climate change scenarios.

  1. Recovery potential of a western lowland gorilla population following a major Ebola outbreak: results from a ten year study.

    Science.gov (United States)

    Genton, Céline; Cristescu, Romane; Gatti, Sylvain; Levréro, Florence; Bigot, Elodie; Caillaud, Damien; Pierre, Jean-Sébastien; Ménard, Nelly

    2012-01-01

    Investigating the recovery capacity of wildlife populations following demographic crashes is of great interest to ecologists and conservationists. Opportunities to study these aspects are rare due to the difficulty of monitoring populations both before and after a demographic crash. Ebola outbreaks in central Africa have killed up to 95% of the individuals in affected western lowland gorilla (Gorilla gorilla gorilla) populations. Assessing whether and how fast affected populations recover is essential for the conservation of this critically endangered taxon. The gorilla population visiting Lokoué forest clearing, Odzala-Kokoua National Park, Republic of the Congo, has been monitored before, two years after and six years after Ebola affected it in 2004. This allowed us to describe Ebola's short-term and long-term impacts on the structure of the population. The size of the population, which included around 380 gorillas before the Ebola outbreak, dropped to less than 40 individuals after the outbreak. It then remained stable for six years after the outbreak. However, the demographic structure of this small population has significantly changed. Although several solitary males have disappeared, the immigration of adult females, the formation of new breeding groups, and several birth events suggest that the population is showing potential to recover. During the outbreak, surviving adult and subadult females joined old solitary silverbacks. Those females were subsequently observed joining young silverbacks, forming new breeding groups where they later gave birth. Interestingly, some females were observed joining silverbacks that were unlikely to have sired their infant, but no infanticide was observed. The consequences of the Ebola outbreak on the population structure were different two years and six years after the outbreak. Therefore, our results could be used as demographic indicators to detect and date outbreaks that have happened in other, non-monitored gorilla

  2. Recovery potential of a western lowland gorilla population following a major Ebola outbreak: results from a ten year study.

    Directory of Open Access Journals (Sweden)

    Céline Genton

    Full Text Available Investigating the recovery capacity of wildlife populations following demographic crashes is of great interest to ecologists and conservationists. Opportunities to study these aspects are rare due to the difficulty of monitoring populations both before and after a demographic crash. Ebola outbreaks in central Africa have killed up to 95% of the individuals in affected western lowland gorilla (Gorilla gorilla gorilla populations. Assessing whether and how fast affected populations recover is essential for the conservation of this critically endangered taxon. The gorilla population visiting Lokoué forest clearing, Odzala-Kokoua National Park, Republic of the Congo, has been monitored before, two years after and six years after Ebola affected it in 2004. This allowed us to describe Ebola's short-term and long-term impacts on the structure of the population. The size of the population, which included around 380 gorillas before the Ebola outbreak, dropped to less than 40 individuals after the outbreak. It then remained stable for six years after the outbreak. However, the demographic structure of this small population has significantly changed. Although several solitary males have disappeared, the immigration of adult females, the formation of new breeding groups, and several birth events suggest that the population is showing potential to recover. During the outbreak, surviving adult and subadult females joined old solitary silverbacks. Those females were subsequently observed joining young silverbacks, forming new breeding groups where they later gave birth. Interestingly, some females were observed joining silverbacks that were unlikely to have sired their infant, but no infanticide was observed. The consequences of the Ebola outbreak on the population structure were different two years and six years after the outbreak. Therefore, our results could be used as demographic indicators to detect and date outbreaks that have happened in other, non

  3. Interannual hydroclimatic variability and the 2009-2011 extreme ENSO phases in Colombia: from Andean glaciers to Caribbean lowlands

    Science.gov (United States)

    Bedoya-Soto, Juan Mauricio; Poveda, Germán; Trenberth, Kevin E.; Vélez-Upegui, Jorge Julián

    2018-03-01

    During 2009-2011, Colombia experienced extreme hydroclimatic events associated with the extreme phases of El Niño-Southern Oscillation (ENSO). Here, we study the dynamics of diverse land-atmosphere phenomena involved in such anomalous events at continental, regional, and local scales. Standardized anomalies of precipitation, 2-m temperature, total column water (TCW), volumetric soil water (VSW), temperature at 925 hPa, surface sensible heat (SSH), latent heat (SLH), evaporation (EVP), and liquid water equivalent thickness (LWET) are analyzed to assess atmosphere-land controls and relationships over tropical South America (TropSA) during 1986-2013 (long term) and 2009-2011 (ENSO extreme phases). An assessment of the interannual covariability between precipitation and 2-m temperature is performed using singular value decomposition (SVD) to identify the dominant spatiotemporal modes of hydroclimatic variability over the region's largest river basins (Amazon, Orinoco, Tocantins, Magdalena-Cauca, and Essequibo). ENSO, its evolution in time, and strong and consistent spatial structures emerge as the dominant mode of variability. In situ anomalies during both extreme phases of ENSO 2009-2011 over the Magdalena-Cauca River basins are linked at the continental scale. The ENSO-driven hydroclimatic effects extend from the diurnal cycle to interannual timescales, as reflected in temperature data from tropical glaciers and the rain-snow boundary in the highest peaks of the Central Andes of Colombia to river levels along the Caribbean lowlands of the Magdalena-Cauca River basin.

  4. Comparative ocular anatomy of the western lowland gorilla.

    Science.gov (United States)

    Knapp, Stefanie; McCulley, James P; Alvarado, Thomas P; Hogan, R Nick

    2007-01-01

    To examine the lowland gorilla (Gorilla gorilla gorilla) eye and determine similarities to and differences between the mountain gorilla (Gorilla gorilla beringei) and the human eye. In addition, we compare our findings of G. g. gorilla to previous reports on the eye of this subspecies. A 13-year-old deceased male lowland gorilla and a 34-year-old deceased female lowland gorilla were included in the study. Gross and microscopic examinations of the formalin-fixed right eyeball of each gorilla were carried out. Globe dimensions of G. g. gorilla were similar to G. g. beringei and to humans. The limbal conjunctival epithelium and the choroid were densely pigmented. However, the distribution of the conjunctival pigment ring was different to that of G. g. beringei and the melanocytes of the choroid were unusually round. There were deep crypts in the anterior border layer of the iris, and the epithelium of the pars plana was uniquely irregular. Vertical corneal diameter was observed to be equal or greater than horizontal diameter in G. g. gorilla, which is in contrast to humans and to previous findings for G. g. beringei. Corneal thickness was closer to that of humans than to G. g. beringei. Posterior lens capsule thickness was noticeably greater than that of humans. Although some variation between the ocular anatomy of G. g. gorilla and G. g. beringei does exist, the gross and microscopic findings closely resemble each other in these two subspecies. In addition, the eye of Gorilla appears remarkably similar to the human eye. However, comparison of measurements with those in humans is somewhat limited because formalin-fixation can introduce tissue shrinkage and artifact.

  5. Water level fluctuations in the Congo basin derived from ENVISAT satellite altimetry

    OpenAIRE

    Becker, M.; da Silva, J. S.; Calmant, Stéphane; Robinet, V.; Linguet, L.; Seyler, Frédérique

    2014-01-01

    In the Congo Basin, the elevated vulnerability of food security and the water supply implies that sustainable development strategies must incorporate the effects of climate change on hydrological regimes. However, the lack of observational hydro-climatic data over the past decades strongly limits the number of studies investigating the effects of climate change in the Congo Basin. We present the largest altimetry-based dataset of water levels ever constituted over the entire Congo Basin. This...

  6. Tropical Soil Chemistry

    DEFF Research Database (Denmark)

    Borggaard, Ole K.

    and environmental protection. Tropical Soil Chemistry by Ole K. Borggaard provides an overview of the composition, occurrence, properties, processes, formation, and environmental vulnerability of various tropical soil types (using American Soil Taxonomy for classification). The processes and the external factors...... soil chemical issues are also presented to assess when, why, and how tropical soils differ from soils in other regions. This knowledge can help agricultural specialists in the tropics establish sustainable crop production. Readers are assumed to be familiar with basic chemistry, physics...

  7. Congo Basin precipitation: Assessing seasonality, regional interactions, and sources of moisture

    Science.gov (United States)

    Dyer, Ellen L. E.; Jones, Dylan B. A.; Nusbaumer, Jesse; Li, Harry; Collins, Owen; Vettoretti, Guido; Noone, David

    2017-07-01

    Precipitation in the Congo Basin was examined using a version of the National Center for Atmospheric Research Community Earth System Model (CESM) with water tagging capability. Using regionally defined water tracers, or tags, the moisture contribution from different source regions to Congo Basin precipitation was investigated. We found that the Indian Ocean and evaporation from the Congo Basin were the dominant moisture sources and that the Atlantic Ocean was a comparatively small source of moisture. In both rainy seasons the southwestern Indian Ocean contributed about 21% of the moisture, while the recycling ratio for moisture from the Congo Basin was about 25%. Near the surface, a great deal of moisture is transported from the Atlantic into the Congo Basin, but much of this moisture is recirculated back over the Atlantic in the lower troposphere. Although the southwestern Indian Ocean is a major source of Indian Ocean moisture, it is not associated with the bulk of the variability in precipitation over the Congo Basin. In wet years, more of the precipitation in the Congo Basin is derived from Indian Ocean moisture, but the spatial distribution of the dominant sources is shifted, reflecting changes in the midtropospheric circulation over the Indian Ocean. During wet years there is increased transport of moisture from the equatorial and eastern Indian Ocean. Our results suggest that reliably capturing the linkages between the large-scale circulation patterns over the Indian Ocean and the local circulation over the Congo Basin is critical for future projections of Congo Basin precipitation.

  8. Therapeutic management of Crimean-Congo haemorrhagic fever.

    Science.gov (United States)

    de la Calle-Prieto, Fernando; Martín-Quirós, Alejandro; Trigo, Elena; Mora-Rillo, Marta; Arsuaga, Marta; Díaz-Menéndez, Marta; Arribas, José Ramón

    2017-06-29

    Crimean-Congo haemorrhagic fever has been reported in more than 30 countries in Africa, Asia, the Middle East and Eastern Europe, with an increasing incidence in recent years, especially in Europe. Because no specific treatments have demonstrated efficacy, supportive treatment is essential, as well as the provision of a centre with the appropriate means to guarantee the safety of its healthcare professionals. Laboratory monitoring of thrombocytopenia, severe coagulopathy or liver failure is of critical importance. Patients with Crimean-Congo haemorrhagic fever should be admitted to High Level Isolation Units where appropriate biocontainment procedures can prevent nosocomial transmission through infected fluids or accidents with contaminated material. In case of high-risk exposures, early administration of ribavirin should be considered. Copyright © 2017. Publicado por Elsevier España, S.L.U.

  9. Photoluminescence study of Congo red molecules under high pressure

    International Nuclear Information System (INIS)

    Wang, Z.P.; Zhang, Z.M.; Ding, Z.J.

    2007-01-01

    Pressure-induced changes on fluorescence spectra of Congo red molecules were examined up to 8.7 GPa using a diamond anvil cell at room temperature. The spectra changes are demonstrated to be sensitive to the pressure and solvent conditions. At hydrostatic pressure and with a solvent used as a pressure transmitting medium the fluorescence spectra show increase of intensity with elevated pressure up to about 2.3 GPa and then drop at higher pressures. For Congo red crystal under quasi-hydrostatic condition without solvent the fluorescence intensity decreases monotonically and the lower energy band becomes dominant with the pressure increasing. The three vibronic bands show red shifts with increase of pressure

  10. Preliminary studies in rice-fish culture in a rainfed lowland ecology ...

    African Journals Online (AJOL)

    Preliminary studies in rice-fish culture in a rainfed lowland ecology in Ghana. PKA Dartey, RK Bam, J Ofori. Abstract. Mixed farms of rice and fish are yet to receive attention in Ghana, despite lowland rice being grown under inundation in most areas nationwide. In a preliminary study, Nile tilapia (Oreochromis niloticus) was ...

  11. Preliminary studies in rice-fish culture in a rainfed lowland ecology ...

    African Journals Online (AJOL)

    Mixed farms of rice and fish are yet to receive attention in Ghana, despite lowland rice being grown under inundation in most areas nationwide. In a preliminary study, Nile tilapia (Oreochromis niloticus) was successfully cultured in a rainfed lowland rice farm, although no additional care was provided for fishes. The highest ...

  12. Neglected tropical diseases

    Directory of Open Access Journals (Sweden)

    David Molyneux

    2013-08-01

    Full Text Available Seventeen neglected tropical diseases (NTDs have been identified by the World Health Organization (WHO. It is estimated that over 1 billion people are infected with NTDs, with a further 1 billion at risk. The majority of NTDs occur in the tropics and sub-tropics and have particular characteristics in common.

  13. Tropical Freshwater Biology

    African Journals Online (AJOL)

    Tropical Freshwater Biology promotes the publication of scientific contributions in the field of freshwater biology in the tropical and subtropical regions of the world. One issue is published annually but this number may be increased. Original research papers and short communications on any aspect of tropical freshwater ...

  14. Quality maintenance Tropical Plants

    Directory of Open Access Journals (Sweden)

    Gláucia Moraes Dias

    2016-11-01

    Full Text Available The climatic characteristics of the country favor the cultivation of tropical flowers. The continued expansion of this market is due the beauty, exoticit nature and postharvest longevity of flower. However, little is known about the postharvest of tropical plants. Therefore, this paper provides information on harvest, handling and storage of cut tropical plantspostharvest, storage temperature, conditioning solution.

  15. A Q fever case mimicking crimean-congo haemorrhagic fever

    Directory of Open Access Journals (Sweden)

    O Karabay

    2011-01-01

    Full Text Available Coxiella burnetii is the bacterium that causes Q fever. Human infection is mainly transmitted from cattle, goats and sheep. The disease is usually self-limited. Pneumonia and hepatitis are the most common clinical manifestations. In this study, we present a case of Q fever from the western part of Turkey mimicking Crimean-Congo haemorrhagic fever (CCHF in terms of clinical and laboratory findings.

  16. Democratic Republic of Congo: Background and U.S. Policy

    Science.gov (United States)

    2013-06-29

    ethnic Hutu extremists who fled to Congo from Rwanda after helping to carry out the 1994 genocide there; “Mai Mai,” a term that broadly refers to a... Rwanda , Uganda, Angola, and South Africa. U.S. policymakers, including in Congress, continue to debate the relative effectiveness of various policy tools...institutions and the military progressively deteriorated, while regional civil conflicts and the genocide in neighboring Rwanda spilled over the border

  17. Crimean-Congo hemorrhagic fever in Iran and neighboring countries

    DEFF Research Database (Denmark)

    Chinikar, S; Ghiasi, Seyed Mojtaba; Hewson, R

    2010-01-01

    Crimean-Congo hemorrhagic fever (CCHF) is a zoonotic viral disease that is asymptomatic in infected livestock, but a serious threat to humans. Human infections begin with nonspecific febrile symptoms, but progress to a serious hemorrhagic syndrome with a case fatality rate of 2-50%. Although the ...... in Iran and neighboring countries and provide evidence of over 5000 confirmed cases of CCHF in a single period/season....

  18. Mycoremediation of congo red dye by filamentous fungi

    OpenAIRE

    Bhattacharya, Sourav; Das, Arijit; G, Mangai.; K, Vignesh.; J, Sangeetha.

    2011-01-01

    Azo, anthroquinone and triphenylmethane dyes are the major classes of synthetic colourants, which are difficult to degrade and have received considerable attention. Congo red, a diazo dye, is considered as a xenobiotic compound, and is recalcitrant to biodegradative processes. Nevertheless, during the last few years it has been demonstrated that several fungi, under certain environmental conditions, are able to transfer azo dyes to non toxic products using laccases. The aim of this work was t...

  19. Possible sexual transmission of Crimean-Congo hemorrhagic fever

    Directory of Open Access Journals (Sweden)

    Natalia Yurievna Pshenichnaya

    2016-04-01

    Full Text Available Three cases of family transmission of laboratory-confirmed Crimean-Congo hemorrhagic fever (CCHF among spouses are reported. These spouses had sexual contact at the end of the incubation period or during the early stage of the mild form of CCHF, without any hemorrhagic symptoms in the first infected spouse. This report demonstrates that sexual contact may represent a real risk of CCHF transmission, even if the patient only experiences mild symptoms.

  20. Going for the play: Structural interpretation in offshore Congo

    Energy Technology Data Exchange (ETDEWEB)

    Platt, N.; Philip, P. (GECO-PRAKLA Exploration Services, Woking (United Kingdom)); Walter, S. (ARK Geophysics Ltd., Milton Keynes, (United Kingdom))

    1993-01-01

    Looking for new hydrocarbons in frontier areas, geologists and geophysicists use very trick in the book: plate tectonics, magnetic and gravity data, plain old geological horse sense and lots of seismic data. An interpretation team is followed, as they pick their way through a seismic survey shot in offshore Congo, Africa, searching for those areas (the plays) that show the greatest promise. 17 figs., 9 refs.

  1. Technical Analysis and Characterization of Southern Cayo, Belize for Tropical Testing and Evaluation of Foliage Penetration Remote Sensing Systems

    Science.gov (United States)

    2011-05-01

    Office, Chile and the U.S. Air Force Office of Scientific Research, Brazil . These organizations seek first rate scientific collaboration in science and...coastal areas, the terrain changes from mangrove swamp to tropical pine savannah and hardwood forest. The interlocking networks of rivers, creeks, and...broad-leaved forest; (2) lowland pine forest; (3) submontane pine forest; (4) submontane broadleaved forest; (5) mangrove and littoral forest; (6

  2. An initial investigation into the organic matter biogeochemistry of the Congo River

    Science.gov (United States)

    Spencer, Robert G.M.; Hernes, Peter J.; Aufdenkampe, Anthony K.; Baker, Andy; Gulliver, Pauline; Stubbins, Aron; Aiken, George R.; Dyda, Rachael Y.; Butler, Kenna D.; Mwamba, Vincent L.; Mangangu, Arthur M.; Wabakanghanzi, Jose N.; Six, Johan

    2012-01-01

    The Congo River, which drains pristine tropical forest and savannah and is the second largest exporter of terrestrial carbon to the ocean, was sampled in early 2008 to investigate organic matter (OM) dynamics in this historically understudied river basin. We examined the elemental (%OC, %N, C:N), isotopic (δ13C, Δ14C, δ15N) and biochemical composition (lignin phenols) of coarse particulate (>63 μm; CPOM) and fine particulate (0.7–63 μm; FPOM) OM and DOC, δ13C, Δ14C and lignin phenol composition with respect to dissolved OM (14C = -62.2 ± -13.2‰, n = 5) compared to CPOM and DOM (mean Δ14C = 55.7 ± 30.6‰, n = 4 and 73.4 ± 16.1‰, n = 5 respectively). The modern radiocarbon ages for DOM belie a degraded lignin compositional signature (i.e. elevated acid:aldehyde ratios (Ad:Al) relative to CPOM and FPOM), and indicate that the application of OM degradation patterns derived from particulate phase studies to dissolved samples needs to be reassessed: these elevated ratios are likely attributable to fractionation processes during solubilization of plant material. The relatively low DOM carbon-normalized lignin yields (Λ8; 0.67–1.12 (mg(100 mg OC)-1)) could also reflect fractionation processes, however, they have also been interpreted as an indication of significant microbial or algal sources of DOM. CPOM appears to be well preserved higher vascular plant material as evidenced by its modern radiocarbon age, elevated C:N (17.2–27.1) and Λ8 values (4.56–7.59 (mg(100 mg OC)-1)). In relation to CPOM, the aged FPOM fraction (320–580 ybp 14C ages) was comparatively degraded, as demonstrated by its nitrogen enrichment (C:N 11.4–14.3), lower Λ8 (2.80–4.31 (mg(100 mg OC)-1)) and elevated lignin Ad:Al values similar to soil derived OM. In this study we observed little modification of the OM signature from sample sites near the cities of Brazzaville and Kinshasa to the head of the estuary (~350 km) highlighting the potential for future studies to

  3. Water availability not fruitfall modulates the dry season distribution of frugivorous terrestrial vertebrates in a lowland Amazon forest.

    Directory of Open Access Journals (Sweden)

    Omar Stalin Landázuri Paredes

    Full Text Available Terrestrial vertebrate frugivores constitute one of the major guilds in tropical forests. Previous studies show that the meso-scale distribution of this group is only weakly explained by variables such as altitude and tree basal area in lowland Amazon forests. For the first time we test whether seasonally limiting resources (water and fallen fruit affect the dry season distribution in 25 species of terrestrial vertebrates. To examine the effects of the spatial availability of fruit and water on terrestrial vertebrates we used a standardized, regularly spaced arrangement of camera-traps within 25km2 of lowland Amazon forest. Generalized linear models (GLMs were then used to examine the influence of four variables (altitude, distance to large rivers, distance to nearest water, and presence vs absence of fruits on the number of photos on five functional groups (all frugivores, small, medium, large and very large frugivores and on seven of the most abundant frugivore species (Cuniculus paca, Dasyprocta leporina, Mazama americana, Mazama nemorivaga, Myoprocta acouchy, Pecari tajacu and Psophia crepitans. A total of 279 independent photos of 25 species were obtained from 900 camera-trap days. For most species and three functional groups, the variation in the number of photos per camera was significantly but weakly explained by the GLMs (deviance explained ranging from 6.2 to 48.8%. Generally, we found that the presence of water availability was more important than the presence of fallen fruit for the groups and species studied. Medium frugivores, large-bodied frugivores, and two of the more abundant species (C. paca and P. crepitans were recorded more frequently closer to water bodies; while none of the functional groups nor the most abundant species showed any significant relationship with the presence of fallen fruit. Two functional groups and two of the seven most common frugivore species assessed in the GLMs showed significant results with species

  4. Water availability not fruitfall modulates the dry season distribution of frugivorous terrestrial vertebrates in a lowland Amazon forest.

    Science.gov (United States)

    Paredes, Omar Stalin Landázuri; Norris, Darren; Oliveira, Tadeu Gomes de; Michalski, Fernanda

    2017-01-01

    Terrestrial vertebrate frugivores constitute one of the major guilds in tropical forests. Previous studies show that the meso-scale distribution of this group is only weakly explained by variables such as altitude and tree basal area in lowland Amazon forests. For the first time we test whether seasonally limiting resources (water and fallen fruit) affect the dry season distribution in 25 species of terrestrial vertebrates. To examine the effects of the spatial availability of fruit and water on terrestrial vertebrates we used a standardized, regularly spaced arrangement of camera-traps within 25km2 of lowland Amazon forest. Generalized linear models (GLMs) were then used to examine the influence of four variables (altitude, distance to large rivers, distance to nearest water, and presence vs absence of fruits) on the number of photos on five functional groups (all frugivores, small, medium, large and very large frugivores) and on seven of the most abundant frugivore species (Cuniculus paca, Dasyprocta leporina, Mazama americana, Mazama nemorivaga, Myoprocta acouchy, Pecari tajacu and Psophia crepitans). A total of 279 independent photos of 25 species were obtained from 900 camera-trap days. For most species and three functional groups, the variation in the number of photos per camera was significantly but weakly explained by the GLMs (deviance explained ranging from 6.2 to 48.8%). Generally, we found that the presence of water availability was more important than the presence of fallen fruit for the groups and species studied. Medium frugivores, large-bodied frugivores, and two of the more abundant species (C. paca and P. crepitans) were recorded more frequently closer to water bodies; while none of the functional groups nor the most abundant species showed any significant relationship with the presence of fallen fruit. Two functional groups and two of the seven most common frugivore species assessed in the GLMs showed significant results with species

  5. Water-carbon Links in a Tropical Forest: How Interbasin Groundwater Flow Affects Carbon Fluxes and Ecosystem Carbon Budgets

    Energy Technology Data Exchange (ETDEWEB)

    Genereux, David [North Carolina State Univ., Raleigh, NC (United States); Osburn, Christopher [North Carolina State Univ., Raleigh, NC (United States); Oberbauer, Steven [Florida Intl Univ., Miami, FL (United States); Oviedo Vargas, Diana [North Carolina State Univ., Raleigh, NC (United States); Dierick, Diego [Florida Intl Univ., Miami, FL (United States)

    2017-03-27

    This report covers the outcomes from a quantitative, interdisciplinary field investigation of how carbon fluxes and budgets in a lowland tropical rainforest are affected by the discharge of old regional groundwater into streams, springs, and wetlands in the forest. The work was carried out in a lowland rainforest of Costa Rica, at La Selva Biological Station. The research shows that discharge of regional groundwater high in dissolved carbon dioxide represents a significant input of carbon to the rainforest "from below", an input that is on average larger than the carbon input "from above" from the atmosphere. A stream receiving discharge of regional groundwater had greatly elevated emissions of carbon dioxide (but not methane) to the overlying air, and elevated downstream export of carbon from its watershed with stream flow. The emission of deep geological carbon dioxide from stream water elevates the carbon dioxide concentrations in air above the streams. Carbon-14 tracing revealed the presence of geological carbon in the leaves and stems of some riparian plants near streams that receive inputs of regional groundwater. Also, discharge of regional groundwater is responsible for input of dissolved organic matter with distinctive chemistry to rainforest streams and wetlands. The discharge of regional groundwater in lowland surface waters has a major impact on the carbon cycle in this and likely other tropical and non-tropical forests.

  6. Diversity and host range of foliar fungal endophytes: are tropical leaves biodiversity hotspots?

    Science.gov (United States)

    Arnold, A Elizabeth; Lutzoni, F

    2007-03-01

    Fungal endophytes are found in asymptomatic photosynthetic tissues of all major lineages of land plants. The ubiquity of these cryptic symbionts is clear, but the scale of their diversity, host range, and geographic distributions are unknown. To explore the putative hyperdiversity of tropical leaf endophytes, we compared endophyte communities along a broad latitudinal gradient from the Canadian arctic to the lowland tropical forest of central Panama. Here, we use molecular sequence data from 1403 endophyte strains to show that endophytes increase in incidence, diversity, and host breadth from arctic to tropical sites. Endophyte communities from higher latitudes are characterized by relatively few species from many different classes of Ascomycota, whereas tropical endophyte assemblages are dominated by a small number of classes with a very large number of endophytic species. The most easily cultivated endophytes from tropical plants have wide host ranges, but communities are dominated by a large number of rare species whose host range is unclear. Even when only the most easily cultured species are considered, leaves of tropical trees represent hotspots of fungal species diversity, containing numerous species not yet recovered from other biomes. The challenge remains to recover and identify those elusive and rarely cultured taxa with narrower host ranges, and to elucidate the ecological roles of these little-known symbionts in tropical forests.

  7. Reviews and syntheses: Field data to benchmark the carbon cycle models for tropical forests

    Science.gov (United States)

    Clark, Deborah A.; Asao, Shinichi; Fisher, Rosie; Reed, Sasha; Reich, Peter B.; Ryan, Michael G.; Wood, Tana E.; Yang, Xiaojuan

    2017-10-01

    For more accurate projections of both the global carbon (C) cycle and the changing climate, a critical current need is to improve the representation of tropical forests in Earth system models. Tropical forests exchange more C, energy, and water with the atmosphere than any other class of land ecosystems. Further, tropical-forest C cycling is likely responding to the rapid global warming, intensifying water stress, and increasing atmospheric CO2 levels. Projections of the future C balance of the tropics vary widely among global models. A current effort of the modeling community, the ILAMB (International Land Model Benchmarking) project, is to compile robust observations that can be used to improve the accuracy and realism of the land models for all major biomes. Our goal with this paper is to identify field observations of tropical-forest ecosystem C stocks and fluxes, and of their long-term trends and climatic and CO2 sensitivities, that can serve this effort. We propose criteria for reference-level field data from this biome and present a set of documented examples from old-growth lowland tropical forests. We offer these as a starting point towards the goal of a regularly updated consensus set of benchmark field observations of C cycling in tropical forests.

  8. Crash and rebound of indigenous populations in lowland South America

    Science.gov (United States)

    Hamilton, Marcus J.; Walker, Robert S.; Kesler, Dylan C.

    2014-04-01

    Lowland South America has long been a battle-ground between European colonization and indigenous survival. Initial waves of European colonization brought disease epidemics, slavery, and violence that had catastrophic impacts on indigenous cultures. In this paper we focus on the demography of 238 surviving populations in Brazil. We use longitudinal censuses from all known indigenous Brazilian societies to quantify three demographic metrics: 1) effects of European contact on indigenous populations; 2) empirical estimates of minimum viable population sizes; and 3) estimates of post-contact population growth rates. We use this information to conduct population viability analysis (PVA). Our results show that all surviving populations suffered extensive mortality during, and shortly after, contact. However, most surviving populations exhibit positive growth rates within the first decade post-contact. Our findings paint a positive demographic outlook for these indigenous populations, though long-term survival remains subject to powerful externalities, including politics, economics, and the pervasive illegal exploitation of indigenous lands.

  9. Acidizing of Zechstein Main Dolomite in the Polish lowlands

    Energy Technology Data Exchange (ETDEWEB)

    Bierdzychi, W

    1966-07-01

    The first acidizing of Zechstein Dolomite in the Polish Lowlands was carried out in 1961. In the initial stage, a tendency existed toward multistage acidizing, and preheated acidizing fluid was used. In a preliminary operation, an acid having the concentration 12-36% was used for washing out the borehole. No additives were utilized except formalin for corrosion inhibition. In order to increase the absorption capacity, hydraulic perforations were used. The composition of acidizing fluid was determined in a preliminary study for any individual reservoir. From laboratory study, it was concluded also that the required time of 3-4 hr was sufficient for the exhaustion of acid. The pre-heating of the acid at the bottom of the hole by exothermic reaction with metallic magnesium was abandoned in the later stage of operations.

  10. Kax and kol: Collapse and resilience in lowland Maya civilization

    Science.gov (United States)

    Dunning, Nicholas P.; Beach, Timothy P.; Luzzadder-Beach, Sheryl

    2012-01-01

    Episodes of population loss and cultural change, including the famous Classic Collapse, punctuated the long course of Maya civilization. In many cases, these downturns in the fortunes of individual sites and entire regions included significant environmental components such as droughts or anthropogenic environmental degradation. Some afflicted areas remained depopulated for long periods, whereas others recovered more quickly. We examine the dynamics of growth and decline in several areas in the Maya Lowlands in terms of both environmental and cultural resilience and with a focus on downturns that occurred in the Terminal Preclassic (second century Common Era) and Terminal Classic (9th and 10th centuries CE) periods. This examination of available data indicates that the elevated interior areas of the Yucatán Peninsula were more susceptible to system collapse and less suitable for resilient recovery than adjacent lower-lying areas. PMID:22371571

  11. Integrated analysis of water quality in a mesoscale lowland basin

    Directory of Open Access Journals (Sweden)

    A. Habeck

    2005-01-01

    Full Text Available This article describes a modelling study on nitrogen transport from diffuse sources in the Nuthe catchment, representing a typical lowland region in the north-eastern Germany. Building on a hydrological validation performed in advance using the ecohydrological model SWIM, the nitrogen flows were simulated over a 20-year period (1981-2000. The relatively good quality of the input data, particularly for the years from 1993 to 2000, enabled the nitrogen flows to be reproduced sufficiently well, although modelling nutrient flows is always associated with a great deal of uncertainty. Subsequently, scenario calculations were carried out in order to investigate how nitrogen transport from the catchment could be further reduced. The selected scenario results with the greatest reduction of nitrogen washoff will briefly be presented in the paper.

  12. Leaching and residual activity of imidazolinone herbicides in lowland soils

    Directory of Open Access Journals (Sweden)

    João Paulo Refatti

    Full Text Available ABSTRACT: Herbicides used in the Clearfield® rice (Oryza sativa L. production system have a potential for leaching. This can result in contamination of underground water resources and cause injury to not tolerant crops that are sown in a succession and/or crop rotation. The objective of this study was to determine the leaching potential and the residual activity of the herbicides used in the Clearfield® rice system. The experiment was conducted over a period of two years and consisted of conducting a field test to be followed by two bioassays with a year of difference between their implementation. Initially an experiment was conducted in lowland area where it was planted the cultivar of rice ‘PUITA INTA CL’. Approximately one and two years thereafter, soil samples from each plot were collected at intervals of 5cm to a depth of 30cm (B factor for the bioassay to evaluate persistence of herbicides. Factor A was composed of mixtures formulated of imazethapyr + imazapic (75 + 25g a.i. L-1, imazapyr + imazapic (525 + 175g a.i. kg-1 in two doses, imazethapyr (100g a.i. L-1 and treatment control without application. Basing on results, it was concluded that the mixtures imazethapyr + imazapic, imazapyr + imazapic and imazethapyr leached into the soil, reaching depths of up to 25cm in lowland soil. Imidazolinone herbicides used today in the irrigated rice Clearfield® system are persistent in soil, and their phytotoxic activity can be observed up to two years after application.

  13. A late Holocene tephrochronology for the Maya Lowlands, Central America

    Science.gov (United States)

    Nooren, K.; Huizinga, A.; Hoek, W.; Bergen, M. V.; Middelkoop, H.

    2012-12-01

    The Maya Lowlands in southern Mexico, Guatemala and Belize were densely populated for thousands of years, and have been the subject of intensive studies on the interaction between humans and their environment. Accurate radiocarbon dating of proxy records and disrupting events has proved to be difficult due to the lack of organic material in many deposits and the 'old carbon effect' related to the calcareous geology of the Yucatan Peninsula. So far, tephrostratigraphy has hardly been used to define time markers for palynological, limnological and archaeological studies in this region, despite the frequent occurrence of tephra fall. With the objective to fill this gap, we developed a tephrochronology for the Maya Lowlands using sediment cores from a flood basin of the Usumacinta-Grijalva delta in southern Mexico. Tephrostratigraphy and radiocarbon dating were used to estimate the timing of past volcanic eruptions, and chemical compositions of glass shards were used to identify potential sources. At least six tephralayers were deposited since 2000 BC, the most notable representing eruptions of El Chichón volcano in the 5th and 15th century AD. The high sulphur emissions accompanying El Chichón's eruptions allowed testing of our age-depth model through a correlation with volcanic sulphate peaks in ice cores from Greenland and Antarctica. We demonstrate the applicability of the established tephrochronological framework in a detailed chronological reconstruction of the formation of the world's largest late Holocene beach ridge plain in southern Mexico. This plain with over 500 beach ridges is a highly sensitive recorder of combined sea level rise, subsidence, storm activity and changes in climate and upstream land use since the dawn of Olmec and Maya cultures circa 5000 years ago.

  14. Seasat synthetic aperture radar ( SAR) response to lowland vegetation types in eastern Maryland and Virginia.

    Science.gov (United States)

    Krohn, M.D.; Milton, N.M.; Segal, D.B.

    1983-01-01

    Examination of Seasat SAR images of eastern Maryland and Virginia reveals botanical distinctions between vegetated lowland areas and adjacent upland areas. Radar returns from the lowland areas can be either brighter or darker than returns from the upland forests. Scattering models and scatterometer measurements predict an increase of 6 dB in backscatter from vegetation over standing water. This agrees with the 30-digital number (DN) increase observed in the digital Seasat data. The density, morphology, and relative geometry of the lowland vegetation with respect to standing water can all affect the strength of the return L band signal.-from Authors

  15. Forest structure in low-diversity tropical forests: a study of Hawaiian wet and dry forests.

    Science.gov (United States)

    Ostertag, Rebecca; Inman-Narahari, Faith; Cordell, Susan; Giardina, Christian P; Sack, Lawren

    2014-01-01

    The potential influence of diversity on ecosystem structure and function remains a topic of significant debate, especially for tropical forests where diversity can range widely. We used Center for Tropical Forest Science (CTFS) methodology to establish forest dynamics plots in montane wet forest and lowland dry forest on Hawai'i Island. We compared the species diversity, tree density, basal area, biomass, and size class distributions between the two forest types. We then examined these variables across tropical forests within the CTFS network. Consistent with other island forests, the Hawai'i forests were characterized by low species richness and very high relative dominance. The two Hawai'i forests were floristically distinct, yet similar in species richness (15 vs. 21 species) and stem density (3078 vs. 3486/ha). While these forests were selected for their low invasive species cover relative to surrounding forests, both forests averaged 5->50% invasive species cover; ongoing removal will be necessary to reduce or prevent competitive impacts, especially from woody species. The montane wet forest had much larger trees, resulting in eightfold higher basal area and above-ground biomass. Across the CTFS network, the Hawaiian montane wet forest was similar to other tropical forests with respect to diameter distributions, density, and aboveground biomass, while the Hawai'i lowland dry forest was similar in density to tropical forests with much higher diversity. These findings suggest that forest structural variables can be similar across tropical forests independently of species richness. The inclusion of low-diversity Pacific Island forests in the CTFS network provides an ∼80-fold range in species richness (15-1182 species), six-fold variation in mean annual rainfall (835-5272 mm yr(-1)) and 1.8-fold variation in mean annual temperature (16.0-28.4°C). Thus, the Hawaiian forest plots expand the global forest plot network to enable testing of ecological theory for

  16. Background Report on Eastern Democratic Republic of the Congo

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Tracy A [ORNL

    2011-05-01

    Each month, approximately 45,000 people die from violence, hunger, disease, and other effects of displacement as a result of war in the Democratic Republic of the Congo (DRC). The country is often said to be plagued by a 'resource curse.' During each period in history since its discovery by the West, the DRC has possessed the resources the world craves and the world has sought these without regard for the consequences to the Congolese people. The catastrophic consequences of Congo's history of natural resource exploitation are the direct and indirect death of millions of Congolese people. The current war in Congo is multi-causal in nature but explanations are often reduced to describing it as an ethic conflict based on objective grievance. Objective grievance such as inequality, ethnic tensions, land disputes, and lack of democracy do exist, but they are neither necessary nor sufficient to explain the cause of the violent conflict, and more importantly, they fall short in explaining why this conflict has continued for years. The reality is the conflict is an economic war in which the trade of conflict minerals, gold and the 3Ts (tin, tantalum, tungsten), is directly linked to the financial sustainability of the groups fighting each other in eastern DRC. Objective grievance is a by-product of the conflict, used to create a false but plausible moral justification to continue violence. This paper examines the history of conflict in the DRC and the socio-economic variables contributing to the current war fought over conflict minerals.

  17. Investigating the remuneration of health workers in the DR Congo: implications for the health workforce and the health system in a fragile setting.

    Science.gov (United States)

    Bertone, Maria Paola; Lurton, Grégoire; Mutombo, Paulin Beya

    2016-11-01

    The financial remuneration of health workers (HWs) is a key concern to address human resources for health challenges. In low-income settings, the exploration of the sources of income available to HWs, their determinants and the livelihoods strategies that those remunerations entail are essential to gain a better understanding of the motivation of the workers and the effects on their performance and on service provision. This is even more relevant in a setting such as the DR Congo, characterized by the inability of the state to provide public services via a well-supported and financed public workforce. Based on a quantitative survey of 1771 HWs in four provinces of the DR Congo, this article looks at the level and the relative importance of each revenue. It finds that Congolese HWs earn their living from a variety of sources and enact different strategies for their financial survival. The main income is represented by the share of user fees for those employed in facilities, and per diems and top-ups from external agencies for those in Health Zone Management Teams (in both cases, with the exception of doctors), while governmental allowances are less relevant. The determinants at individual and facility level of the total income are also modelled, revealing that the distribution of most revenues systematically favours those working in already favourable conditions (urban facilities, administrative positions and positions of authority within facilities). This may impact negatively on the motivation and performance of HWs and on their distribution patters. Finally, our analysis highlights that, as health financing and health workforce reforms modify the livelihood opportunities of HWs, their design and implementation go beyond technical aspects and are unavoidably political. A better consideration of these issues is necessary to propose contextually grounded and politically savvy approaches to reform in the DR Congo. © The Author 2016. Published by Oxford University

  18. Molecular Insights into Crimean-Congo Hemorrhagic Fever Virus

    Directory of Open Access Journals (Sweden)

    Marko Zivcec

    2016-04-01

    Full Text Available Crimean-Congo hemorrhagic fever virus (CCHFV is a tick-borne pathogen that causes high morbidity and mortality. Efficacy of vaccines and antivirals to treat human CCHFV infections remains limited and controversial. Research into pathology and underlying molecular mechanisms of CCHFV and other nairoviruses is limited. Significant progress has been made in our understanding of CCHFV replication and pathogenesis in the past decade. Here we review the most recent molecular advances in CCHFV-related research, and provide perspectives on future research.

  19. Road Expansion and the Fate of Africa's Tropical Forests

    Directory of Open Access Journals (Sweden)

    William F. Laurance

    2017-07-01

    Full Text Available The tropical forests of Africa are experiencing unprecedented changes as a result of a rapid proliferation of roads and other infrastructure. These projects are dramatically increasing access to relatively unexploited regions, particularly in the greater Congo Basin. We highlight some of the most important new projects and describe in detail an ongoing debate about a particular proposed development, the Cross River Superhighway in Nigeria. The scale and pace of new transportation projects, and the profound environmental changes they could bring, underscore a dire need for proactive land-use planning, capacity building, and environmental assessment in the nations of Equatorial Africa. It is no exaggeration to suggest that, unless carefully managed to ensure sustainability, the spate of planned and ongoing projects could irreparably diminish the forests and wildlife populations of Africa's most biologically diverse regions.

  20. The Environmental Legacy of Modern Tropical Deforestation.

    Science.gov (United States)

    Rosa, Isabel M D; Smith, Matthew J; Wearn, Oliver R; Purves, Drew; Ewers, Robert M

    2016-08-22

    Tropical deforestation has caused a significant share of carbon emissions and species losses, but historical patterns have rarely been explicitly considered when estimating these impacts [1]. A deforestation event today leads to a time-delayed future release of carbon, from the eventual decay either of forest products or of slash left at the site [2]. Similarly, deforestation often does not result in the immediate loss of species, and communities may exhibit a process of "relaxation" to their new equilibrium over time [3]. We used a spatially explicit land cover change model [4] to reconstruct the annual rates and spatial patterns of tropical deforestation that occurred between 1950 and 2009 in the Amazon, in the Congo Basin, and across Southeast Asia. Using these patterns, we estimated the resulting gross vegetation carbon emissions [2, 5] and species losses over time [6]. Importantly, we accounted for the time lags inherent in both the release of carbon and the extinction of species. We show that even if deforestation had completely halted in 2010, time lags ensured there would still be a carbon emissions debt of at least 8.6 petagrams, equivalent to 5-10 years of global deforestation, and an extinction debt of more than 140 bird, mammal, and amphibian forest-specific species, which if paid, would increase the number of 20(th)-century extinctions in these groups by 120%. Given the magnitude of these debts, commitments to reduce emissions and biodiversity loss are unlikely to be realized without specific actions that directly address this damaging environmental legacy. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  1. Toxoplasmosis among pregnant women: high seroprevalence and risk factors in Kinshasa, Democratic Republic of Congo.

    Science.gov (United States)

    Doudou, Yobi; Renaud, Piarroux; Coralie, L'Ollivier; Jacqueline, Franck; Hypolite, Situakibanza; Hypolite, Muhindo; Patrick, Mitashi; Andreia, Inocêncio da Luz Raquel; Van Sprundel, Marc; Marleen, Boelaert; Van Geertruyden, Jean-Pierre; Pascal, Lutumba

    2014-01-01

    To determine the seroprevalence of toxoplasmosis in pregnant women, as well as the proportion of acutely infected and risk factors in the Democratic Republic of Congo. Thirty maternities in Kinshasa were randomly selected and women attending antenatal consultation were invited to participate. They were interviewed with a structured questionnaire about known risk factors (age, meat consumption, contact with soil, and presence of cat) and a venous blood sample was taken. Sera were analysed for total immunoglobulins (Ig) by VIDAS Toxo Competition using Enzyme Linked Fluorescent Assay. IgM was determined by VIDIA Toxo IgM and IgG avidity by VIDAS Toxo IgG avidity. A total of 781 women were included. Median age was 28 years old (IQR: 8.5). And 627 women (80.3%; 95% CI: 77.5-83.1) were found to be positive to total Ig and 17 out of 387 (4.4%; 95% CI: 2.3-6.4) were positive to IgM. IgG avidity was low for 2 (11.8%) women, intermediate for 2 (11.8%) and high for 13 women (76.4%). There was no statistically significant association between Toxoplasma gondii infection and any risk factors assessed. In Kinshasa, toxoplasmosis endemicity is highly prevalent. One woman out of twenty five had a recent toxoplasmosis infection and 20% were not protected against primo-infection, indicating a need for measures to prevent and control toxoplasmosis during pregnancy. Copyright © 2014 Asian Pacific Tropical Biomedical Magazine. Published by Elsevier B.V. All rights reserved.

  2. Effects of logging on roadless space in intact forest landscapes of the Congo Basin.

    Science.gov (United States)

    Kleinschroth, Fritz; Healey, John R; Gourlet-Fleury, Sylvie; Mortier, Frédéric; Stoica, Radu S

    2017-04-01

    Forest degradation in the tropics is often associated with roads built for selective logging. The protection of intact forest landscapes (IFL) that are not accessible by roads is high on the biodiversity conservation agenda and a challenge for logging concessions certified by the Forest Stewardship Council (FSC). A frequently advocated conservation objective is to maximize the retention of roadless space, a concept that is based on distance to the nearest road from any point. We developed a novel use of the empty-space function - a general statistical tool based on stochastic geometry and random sets theory - to calculate roadless space in a part of the Congo Basin where road networks have been expanding rapidly. We compared the temporal development of roadless space in certified and uncertified logging concessions inside and outside areas declared IFL in 2000. Inside IFLs, road-network expansion led to a decrease in roadless space by more than half from 1999 to 2007. After 2007, loss leveled out in most areas to close to 0 due to an equilibrium between newly built roads and abandoned roads that became revegetated. However, concessions in IFL certified by FSC since around 2007 continuously lost roadless space and reached a level comparable to all other concessions. Only national parks remained mostly roadless. We recommend that forest-management policies make the preservation of large connected forest areas a top priority by effectively monitoring - and limiting - the occupation of space by roads that are permanently accessible. © 2016 The Authors. Conservation Biology published by Wiley Periodicals, Inc. on behalf of Society for Conservation Biology.

  3. LBA-ECO LC-07 Wetland Extent, Vegetation, and Inundation: Lowland Amazon Basin

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides a map of wetland extent, vegetation type, and dual-season flooding state of the entire lowland Amazon basin. The map was derived from mosaics...

  4. 2005 Puget Sound LiDAR Consortium (PSLC) Topographic LiDAR: North Puget Sound Lowlands

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Terrapoint collected Light Detection and Ranging (LiDAR) data contributing to the Puget Sound Lowlands project of 2005. Arlington, City of Snohomish, Snohomish...

  5. Agro-morphological variation in lowland humid forest accessions of ...

    African Journals Online (AJOL)

    The collection, characterization and conservation of variability within a species remain the key for variety improvement. In Cameroon, maize production is limited by stress conditions common to tropical countries, including drought, pests, diseases, acid soils, etc. One of the impediments to the progress in selection targeted ...

  6. Ocean-atmosphere forcing of South American tropical paleoclimate, LGM to present

    Science.gov (United States)

    Baker, P. A.; Fritz, S. C.; Dwyer, G. S.; Rigsby, C. A.; Silva, C. G.; Burns, S. J.

    2012-12-01

    Because of many recent terrestrial paleoclimatic and marine paleoceanographic records, late Quaternary South American tropical paleoclimate is as well understood as that anywhere in the world. While lessons learned from the recent instrumental record of climate are informative, this record is too short to capture much of the lower frequency variability encountered in the paleoclimate records and much of the observed paleoclimate is without modern analogue. This paleoclimate is known to be regionally variable with significant differences both north and south of the equator and between the western high Andes and eastern lowlands of the Amazon and Nordeste Brazil. Various extrinsic forcing mechanisms affected climate throughout the period, including global concentrations of GHGs, Northern Hemisphere ice sheet forcing, seasonal insolation forcing of the South American summer monsoon (SASM), millennial-scale Atlantic forcing, and Pacific forcing of the large-scale Walker circulation. The magnitude of the climate response to these forcings varied temporally, largely because of the varying amplitude of the forcing itself. For example, during the last glacial, large-amplitude north Atlantic forcing during Heinrich 1 and the LGM itself, led to wet (dry) conditions south (north) of the equator. During the Holocene, Atlantic forcing was lower amplitude, thus seasonal insolation forcing generally predominated with a weaker-than-normal SASM during the early Holocene resulting in dry conditions in the south-western tropics and wet conditions in the eastern lowlands and Nordeste; in the late Holocene seasonal insolation reached a maximum in the southern tropics and climate conditions reversed.

  7. Adaptive Epigenetic Differentiation between Upland and Lowland Rice Ecotypes Revealed by Methylation-Sensitive Amplified Polymorphism

    OpenAIRE

    Xia, Hui; Huang, Weixia; Xiong, Jie; Tao, Tao; Zheng, Xiaoguo; Wei, Haibin; Yue, Yunxia; Chen, Liang; Luo, Lijun

    2016-01-01

    The stress-induced epimutations could be inherited over generations and play important roles in plant adaption to stressful environments. Upland rice has been domesticated in water-limited environments for thousands of years and accumulated drought-induced epimutations of DNA methylation, making it epigenetically differentiated from lowland rice. To study the epigenetic differentiation between upland and lowland rice ecotypes on their drought-resistances, the epigenetic variation was investig...

  8. Old tropical botanical collections

    DEFF Research Database (Denmark)

    Friis, Ib

    2017-01-01

    The early history of botanical collections is reviewed, with particular emphasis on old collections from the tropics. The information available about older and newer botanical collections from the tropics was much improved after World War Two, including better lists of validly published names, more...

  9. Tropical Veterinarian: Submissions

    African Journals Online (AJOL)

    Author Guidelines. 2012 Author Guidelines: Instructions to Authors: TROPICAL VETERINARIAN welcomes original work on all aspects of veterinary science as practiced in the Tropics, including livestock production and management, animal disease (domestic and wild), various aspects of preventive medicine and public ...

  10. Tropical Cyclone Propagation

    National Research Council Canada - National Science Library

    Gray, William

    1994-01-01

    This paper discusses the question of tropical cyclone propagation or why the average tropical cyclone moves 1-2 m/s faster and usually 10-20 deg to the left of its surrounding (or 5-7 deg radius) deep layer (850-300 mb) steering current...

  11. Computing Tropical Varieties

    DEFF Research Database (Denmark)

    Speyer, D.; Jensen, Anders Nedergaard; Bogart, T.

    2005-01-01

    The tropical variety of a d-dimensional prime ideal in a polynomial ring with complex coefficients is a pure d-dimensional polyhedral fan. This fan is shown to be connected in codimension one. We present algorithmic tools for computing the tropical variety, and we discuss our implementation...

  12. Terrestrial Water Flux Responses to Global Warming in Tropical Rainforest Area

    Science.gov (United States)

    Lan, C. W.; Lo, M. H.; Kumar, S.

    2016-12-01

    Precipitation extremes are expected to become more frequent in the changing global climate, which may considerably affect the terrestrial hydrological cycle. In this study, Coupled Model Intercomparison Project Phase 5 (CMIP5) archives have been examined to explore the changes in normalized terrestrial water fluxes (TWFn) (precipitation minus evapotranspiration minus total runoff, divided by the precipitation climatology) in three tropical rainforest areas: Maritime Continent, Congo, and Amazon. Results reveal that a higher frequency of intense precipitation events is predicted for the Maritime Continent in the future climate than in the present climate, but not for the Amazon or Congo rainforests. Nonlinear responses to extreme precipitation lead to a reduced groundwater recharge and a proportionately greater amount of direct runoff, particularly for the Maritime Continent, where both the amount and intensity of precipitation increase under global warming. We suggest that the nonlinear response is related to the existence of a higher near-surface soil moisture over the Maritime Continent than that over the Amazon and Congo rainforests. The wetter soil over the Maritime Continent also leads to an increased subsurface runoff. Thus, increased precipitation extremes and concomitantly reduced terrestrial water fluxes (TWF) lead to an intensified hydrological cycle for the Maritime Continent. This has the potential to result in a strong temporal heterogeneity in soil water distribution affecting the ecosystem of the rainforest region and increasing the risk of flooding and/or landslides.

  13. Terrestrial water flux responses to global warming in tropical rainforest areas

    Science.gov (United States)

    Lan, Chia-Wei; Lo, Min-Hui; Chou, Chia; Kumar, Sanjiv

    2016-05-01

    Precipitation extremes are expected to become more frequent in the changing global climate, which may considerably affect the terrestrial hydrological cycle. In this study, Coupled Model Intercomparison Project Phase 5 archives have been examined to explore the changes in normalized terrestrial water fluxes (precipitation minus evapotranspiration minus total runoff, divided by the precipitation climatology) in three tropical rainforest areas: Maritime Continent, Congo, and Amazon. Results show that a higher frequency of intense precipitation events is predicted for the Maritime Continent in the future climate than in the present climate, but not for the Amazon or Congo rainforests. Nonlinear responses to extreme precipitation lead to a reduced groundwater recharge and a proportionately greater amount of direct runoff, particularly for the Maritime Continent, where both the amount and intensity of precipitation increase under global warming. We suggest that the nonlinear response is related to the existence of a higher near-surface soil moisture over the Maritime Continent than that over the Amazon and Congo rainforests. The wetter soil over the Maritime Continent also leads to an increased subsurface runoff. Thus, increased precipitation extremes and concomitantly reduced terrestrial water fluxes lead to an intensified hydrological cycle for the Maritime Continent. This has the potential to result in a strong temporal heterogeneity in soil water distribution affecting the ecosystem of the rainforest region and increasing the risk of flooding and/or landslides.

  14. Detection of large above-ground biomass variability in lowland forest ecosystems by airborne LiDAR

    Directory of Open Access Journals (Sweden)

    J. Jubanski

    2013-06-01

    Full Text Available Quantification of tropical forest above-ground biomass (AGB over large areas as input for Reduced Emissions from Deforestation and forest Degradation (REDD+ projects and climate change models is challenging. This is the first study which attempts to estimate AGB and its variability across large areas of tropical lowland forests in Central Kalimantan (Indonesia through correlating airborne light detection and ranging (LiDAR to forest inventory data. Two LiDAR height metrics were analysed, and regression models could be improved through the use of LiDAR point densities as input (R2 = 0.88; n = 52. Surveying with a LiDAR point density per square metre of about 4 resulted in the best cost / benefit ratio. We estimated AGB for 600 km of LiDAR tracks and showed that there exists a considerable variability of up to 140% within the same forest type due to varying environmental conditions. Impact from logging operations and the associated AGB losses dating back more than 10 yr could be assessed by LiDAR but not by multispectral satellite imagery. Comparison with a Landsat classification for a 1 million ha study area where AGB values were based on site-specific field inventory data, regional literature estimates, and default values by the Intergovernmental Panel on Climate Change (IPCC showed an overestimation of 43%, 102%, and 137%, respectively. The results show that AGB overestimation may lead to wrong greenhouse gas (GHG emission estimates due to deforestation in climate models. For REDD+ projects this leads to inaccurate carbon stock estimates and consequently to significantly wrong REDD+ based compensation payments.

  15. Western lowland gorillas (Gorilla gorilla gorilla) change their activity patterns in response to frugivory.

    Science.gov (United States)

    Masi, Shelly; Cipolletta, Chloé; Robbins, Martha M

    2009-02-01

    The most important environmental factor explaining interspecies variation in ecology and sociality of the great apes is likely to be variation in resource availability. Relatively little is known about the activity patterns of western lowland gorillas (Gorilla gorilla gorilla), which inhabit a dramatically different environment from the well-studied mountain gorillas (G. beringei beringei). This study aims to provide a detailed quantification of western lowland gorillas' activity budgets using direct observations on one habituated group in Bai Hokou, Central African Republic. We examined how activity patterns of both sexes are shaped by seasonal frugivory. Activity was recorded with 5-min instantaneous sampling between December 2004 and December 2005. During the high-frugivory period the gorillas spent less time feeding and more time traveling than during the low-frugivory period. The silverback spent less time feeding but more time resting than both females and immatures, which likely results from a combination of social and physiological factors. When compared with mountain gorillas, western lowland gorillas spend more time feeding (67 vs. 55%) and traveling (12 vs. 6.5%), but less time resting (21 vs. 34%) and engaging in social/other activities (0.5 vs. 3.6%). This disparity in activity budgets of western lowland gorillas and mountain gorillas may be explained by the more frugivorous diet and the greater dispersion of food resources experienced by western lowland gorillas. Like other apes, western lowland gorillas change their activity patterns in response to changes in the diet. (c) 2008 Wiley-Liss, Inc.

  16. Introduction to tropical geometry

    CERN Document Server

    Maclagan, Diane

    2015-01-01

    Tropical geometry is a combinatorial shadow of algebraic geometry, offering new polyhedral tools to compute invariants of algebraic varieties. It is based on tropical algebra, where the sum of two numbers is their minimum and the product is their sum. This turns polynomials into piecewise-linear functions, and their zero sets into polyhedral complexes. These tropical varieties retain a surprising amount of information about their classical counterparts. Tropical geometry is a young subject that has undergone a rapid development since the beginning of the 21st century. While establishing itself as an area in its own right, deep connections have been made to many branches of pure and applied mathematics. This book offers a self-contained introduction to tropical geometry, suitable as a course text for beginning graduate students. Proofs are provided for the main results, such as the Fundamental Theorem and the Structure Theorem. Numerous examples and explicit computations illustrate the main concepts. Each of t...

  17. The diversity and abundance of ground herbs in lowland mixed dipterocarp forest and heath forest in Brunei Darussalam

    Directory of Open Access Journals (Sweden)

    Nurul Hazlina Zaini

    2014-12-01

    Full Text Available Herbaceous plants are important components of total plant species richness in tropical forests. Ground herb diversity and abundance were studied in a lowland Mixed Dipterocarp forest (Andulau and a heath forest (Bukit Sawat in Brunei Darussalam, Borneo. At each site, all ground herbs in twenty randomly selected 10 × 10 m subplots within a one hectare permanent plot were censused and identified. The study recorded a total of 20 families and 32 genera of ground herbs, with the family Zingiberaceae as the most abundant at both sites. Thirteen genera were recorded only at Andulau and 7 genera were exclusive to Bukit Sawat, with twelve genera common to both sites. Ground herb species richness appear higher at Andulau than Bukit Sawat (37 vs. 29, but this difference was not statistically significant at the subplot level. However, ground herb abundance and density were significantly higher at Bukit Sawat than Andulau (n =  846 vs. 385; 4230 vs. 1925 individuals ha-1. The more open canopy at Bukit Sawat may provide higher light availability here than at Andulau, which is characterised by a closed canopy. We suggest that light availability is the most important environmental factor influencing ground herb density and abundance at these sites. 

  18. a Review of Late Holocene Fluvial Systems in the Karst Maya Lowlands with Focus on the Rio Bravo, Belize

    Science.gov (United States)

    Beach, T.; Luzzadder-Beach, S.; Krause, S.; Doyle, C.

    2015-12-01

    The Maya Lowlands is mostly an internally draining karst region with about 400 m of regional relief. Fluvial and fluviokarst systems drain the edges of this landscape either from low limestone uplands or igneous and metamorphic complexes. Thus far most fluvial research has focused around archaeology projects, and here we review the extant research conducted across the region and new research on the transboundary Rio Bravo watershed of Belize and Guatemala. The Rio Bravo drains a largely old growth tropical forest today, but was partly deforested around ancient Maya cities and farms from 3,000 to 1000 BP. Several studies estimate that 30 to 40 percent of forest survived through the Maya period. Work here has focused on soils and sediment movement along slope catenas, in floodplain sites, and on contributions from groundwater with high dissolved loads of sulfate and calcium. We review radiocarbon dates and present new dates and soil stratigraphy from these sequences to date slope and floodplain movement, and we estimate ancient land use from carbon isotopic and pollen evidence. Aggradation in this watershed occurred by flooding, gypsum precipitation, upland erosion, and ancient Maya canal building and filling for wetland farming. Soil erosion and aggradation started at least by 3,000 BP and continued through the ancient Maya period, though reduced locally by soil conservation, post urban construction, and source reduction, especially in Maya Classic period from 1700 to 1000 BP.

  19. Reaction of congo red in water after irradiation by pulsed intense relativistic electron beam

    International Nuclear Information System (INIS)

    Kikuchi, Takashi; Kondo, Hironobu; Sasaki, Toru; Harada, Nob.; Moriwaki, Hiroshi; Nakanishi, Hiromitsu; Imada, Go

    2011-01-01

    The reaction of congo red, a well-known toxic azo dye, occurred after irradiation by a pulsed intense relativistic electron beam (PIREB). An aquation of congo red was irradiated by PIREB (2 MeV, 0.36 kA, 140 ns). After PIREB irradiation, the solution was measured by electrospray ionization-mass spectrometry and liquid chromatography/mass spectrometry. It was found that congo red underwent a reaction (77% conversion after five shots of PIREB irradiation) and the hydroxylated compounds of the dye were observed as reaction products. (author)

  20. Adsorption of procion red and congo red dyes using microalgae Spirulina sp

    Directory of Open Access Journals (Sweden)

    Risfidian Mohadi

    2017-10-01

    Full Text Available Adsorption of procion red and congo red dyes using microalgae Spirulina sp was conducted. Spirulina sp was obtained by cultivation and production in laboratory scale. Spirulina sp was used as adsorbent for adsorption of dyes. Adsorption process was studied by kinetic and thermodynamic in order to know the adsorption phenomena. The results showed that kinetically congo red is reactive than procion red on Spirulina sp. On the other hand, thermodynamically procion red was stable than congo red on Spirulina sp which was indicated by adsorption capacity, enthalpy, and entropy.

  1. N-Urea Efficiency In Lowland Rice Applied With Azolla

    International Nuclear Information System (INIS)

    Rasjid, Havid; Sisworo, E.L.; Wemay, Y.; Sisworo, W.H.

    2000-01-01

    Two N-fertilizer experiments have been conducted using urea tablet and prill urea combined with Azolla application. Twelve treatments have been tested using 2 rice varieties namely Atomita-4 and IR-64. To enable the determination of N-urea efficiency 15 N labelled urea was used. The experiments were conducted in the dry and wet season (DS and WS) 1994/1995 at the experimental station, pusaka negara, Subang West Java. Data obtained from the two experiments showed that the highest N-urea efficiency was found in Atomita-4 applied with urea-tablet (DS=46,1%, WS= 35,8%). Letting the Azolla grow during one lowland rice growth period could increase the N-urea prill efficiency (±5%) compared when no azolla was applied. Apparently Atomita-4 could use N-urea more efficiently compared to IR-64, showing higher grain yield (atomita-4 DS=6.2 ton ha -1 WS=5.9 ton ha -1 ) vs IR-64 (DS=5.8 ton ha -1 , WS=5.3 ton ha -1 ). Decreasing the levels of TSP not influence to the urea efficiency at the DS and WS

  2. An 8700 year paleoclimate reconstruction from the southern Maya lowlands

    Science.gov (United States)

    Wahl, David B.; Byrne, Roger; Anderson, Lysanna

    2014-01-01

    Analysis of a sediment core from Lago Puerto Arturo, a closed basin lake in northern Peten, Guatemala, has provided an ∼8700 cal year record of climate change and human activity in the southern Maya lowlands. Stable isotope, magnetic susceptibility, and pollen analyses were used to reconstruct environmental change in the region. Results indicate a relatively wet early to middle Holocene followed by a drier late Holocene, which we interpret as reflecting long-term changes in insolation (precession). Higher frequency variability is more likely attributable to changes in ocean/atmosphere circulation in both the North Atlantic and the Pacific Oceans. Pollen and isotope data show that most of the period of prehispanic agricultural settlement, i.e. ∼5000–1000 cal yr BP, was characterized by drier conditions than previous or subsequent periods. The presence ofZea (corn) pollen through peak aridity during the Terminal Classic period (∼1250–1130 cal yr BP) suggests that drought may not have had as negative an impact as previously proposed. A dramatic negative shift in isotope values indicates an increase in precipitation after ∼950 cal yr BP (hereafter BP).

  3. Use of azolla as a nitrogen source of lowland rice

    International Nuclear Information System (INIS)

    Sisworo, E.L.; Widjang, H.S.; Havid, S.; Hendratno; Soleh, S.; Goesworo, S.

    1991-01-01

    A four years experiment has been carried out to study possibility of using azolla as a nitrogen source for lowland rice. The work done in the first year, experiments were conducted in the wet season (WS) and the dry season (DS) of 1984/1985, was evaluate weather azolla could really increase rice yield. In the second year, experiments done in the WS and DS of 1985/1986, N-derived from azolla (N-dfA) and N-derived from urea (N-dfU) in rice plan were determined. The third year work done in the WS and DS of 1986/1987 was conducted to see what extend azolla could be applied in the terms of kg N/ha as a N-source for rice. While the last year was devoted to study the N-balance of azolla and urea, which was done in the DS of 1988/1989. Results of the experiments show that azolla has the same ability as urea to increase rice azolla interacted with urea. By increasing the azolla level N recovery in rice will decrease. The same phenomena was also found with urea. Another interesting fact is that an azolla cover in the rice field could promote N-uptake from urea. (author). 8 refs, 15 tabs

  4. Genetic approaches refine ex situ lowland tapir (Tapirus terrestris) conservation.

    Science.gov (United States)

    Gonçalves da Silva, Anders; Lalonde, Danielle R; Quse, Viviana; Shoemaker, Alan; Russello, Michael A

    2010-01-01

    Ex situ conservation management remains an important tool in the face of continued habitat loss and global environmental change. Here, we use microsatellite marker variation to evaluate conventional assumptions of pedigree-based ex situ population management and directly inform a captive lowland tapir breeding program within a range country. We found relatively high levels of genetic variation (N(total) = 41; mean H(E) = 0.67 across 10 variable loci) and little evidence for relatedness among founder individuals (N(founders) = 10; mean relatedness = -0.05). Seven of 29 putative parent-offspring relationships were excluded by parentage analysis based on allele sharing, and we identified 2 individuals of high genetic value to the population (mk

  5. [Population planning unit is developed in the Congo].

    Science.gov (United States)

    Amouali, C; Poukouta, P

    1989-01-01

    This article is an update on the demographic situation in the Congo and the institutionalization of a population unit in The Ministry of Plan. From 1974-84 the population increased 44.9% going from 1,319,790 to 1,912,429 at a growth rate of 3.48% and possibly doubling in 20 years (2005). However, the major transformation has been the growth of the urban areas over the rural. From 1974-84 the rural population went from 819,430 to 934,849 while the urban population went from 500,360 in 1974 to 977,580 in 1984. The growth rate of the rural areas was 1.22% while that for the urban was 6.38% Infant mortality rate stands at 73/1000; life expectancy is 46.9 for men and 50.0 for women. The average fertility rate is 6. This demographic situation with the inherent problems of the rapidly growing urbanization of the 2 principal cities, Brazzaville and Pointe-Noire, has led to problems in health services and high morbidity and mortality rates. The Government has created 3 national organizations to coordinate population activities in the country: 1) The National Council on Population, (1988) an interministerial council, presided over by the Prime Minister, that defines and formulates national population policies as integral components to the country's socioeconomic development plans; 2) The National Commission on Population (CONAPO), headed by the Minister of Plan, Finance and Economics as the administrative organ of The National Council on Population, and responsible for the technical and evaluation activities of The National Council on Population; and 3) The Population Planning Unit headed by the Director of Human Resources in the Ministry of Plan responsible for identifying, formulating and evaluating population policies in the Congo. These institutions were created as a result of the 1974 Bucharest Conference and the 1984 Arusha Conference were population and development were considered integral components, and of results of 2 censuses and population surveys highlighting

  6. Isotopes in tropical agriculture

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1962-04-15

    Ways in which the use of radioisotopes and radiation can help to improve the agriculture of tropical Africa were discussed by a panel of experts. The panel included scientists from Africa, Europe, and the United States, most of whom had had actual experience dealing with agricultural problems in various parts of tropical Africa. The experts agreed that radioisotopes and radiation might now be employed to particular advantage in tropical Africa to improve crop nutrition and combat insect pests. Other applications discussed were in the fields of hydrology, plant breeding and food preservation

  7. Isotopes in tropical agriculture

    International Nuclear Information System (INIS)

    1962-01-01

    Ways in which the use of radioisotopes and radiation can help to improve the agriculture of tropical Africa were discussed by a panel of experts. The panel included scientists from Africa, Europe, and the United States, most of whom had had actual experience dealing with agricultural problems in various parts of tropical Africa. The experts agreed that radioisotopes and radiation might now be employed to particular advantage in tropical Africa to improve crop nutrition and combat insect pests. Other applications discussed were in the fields of hydrology, plant breeding and food preservation

  8. Discharge and other hydraulic measurements for characterizing the hydraulics of Lower Congo River

    Science.gov (United States)

    Oberg, Kevin; Shelton, John M.; Gardiner, Ned; Jackson, P. Ryan

    2009-01-01

    The first direct measurements of discharge of the Lower Congo River below Malebo Pool and upstream from Kinganga, Democratic Republic of Congo (DRC) were made in July 2008 using acoustic Doppler current profilers, differential GPS, and echo sounders. These measurements were made in support of research that is attempting to understand the distribution of fish species in the Lower Congo River and reasons for separation of species within this large river. Analyses of these measurements show that the maximum depth in the Lower Congo River was in excess of 200 m and maximum water velocities were greater than 4 m/s. The discharge measured near Luozi, DRC was 35,800 m3/s, and decreased slightly beginning midway through the study. Local bedrock controls seem to have a large effect on the flow in the river, even in reaches without waterfalls and rapids. Dramatic changes in bed topography are evident in transects across the river.

  9. Ebola Virus Disease, Democratic Republic of the Congo, 2014.

    Science.gov (United States)

    Nanclares, Carolina; Kapetshi, Jimmy; Lionetto, Fanshen; de la Rosa, Olimpia; Tamfun, Jean-Jacques Muyembe; Alia, Miriam; Kobinger, Gary; Bernasconi, Andrea

    2016-09-01

    During July-November 2014, the Democratic Republic of the Congo underwent its seventh Ebola virus disease (EVD) outbreak. The etiologic agent was Zaire Ebola virus; 66 cases were reported (overall case-fatality rate 74.2%). Through a retrospective observational study of confirmed EVD in 25 patients admitted to either of 2 Ebola treatment centers, we described clinical features and investigated correlates associated with death. Clinical features were mainly generic. At admission, 76% of patients had >1 gastrointestinal symptom and 28% >1 hemorrhagic symptom. The case-fatality rate in this group was 48% and was higher for female patients (67%). Cox regression analysis correlated death with initial low cycle threshold, indicating high viral load. Cycle threshold was a robust predictor of death, as were fever, hiccups, diarrhea, dyspnea, dehydration, disorientation, hematemesis, bloody feces during hospitalization, and anorexia in recent medical history. Differences from other outbreaks could suggest guidance for optimizing clinical management and disease control.

  10. Second International Conference on Crimean-Congo Hemorrhagic Fever.

    Science.gov (United States)

    Spengler, Jessica R; Bente, Dennis A; Bray, Mike; Burt, Felicity; Hewson, Roger; Korukluoglu, Gülay; Mirazimi, Ali; Weber, Friedemann; Papa, Anna

    2018-02-01

    The Second International Conference on Crimean-Congo Hemorrhagic Fever (CCHF) was held in Thessaloniki, Greece, from September 10-13, 2017, and brought together international public health professionals, clinicians, ecologists, and basic laboratory researchers. Nearly 100 participants, representing 24 countries and the World Health Organization (WHO), were in attendance. Meeting sessions covered the epidemiology of CCHF in humans; ticks and virus-tick interactions; wild and domestic animal hosts; molecular virology; taxonomic classification; pathogenesis and animal models; clinical aspects and diagnosis; clinical management and clinical trials; and disease prevention in humans. The concluding session focused on recent WHO recommendations for public health measures and future research. This report summarizes lectures by the invited speakers and highlights advances in the field. Copyright © 2017. Published by Elsevier B.V.

  11. Crimean-Congo Haemorrhagic Fever in Kosova : a fatal case report

    Directory of Open Access Journals (Sweden)

    Raka Lul

    2006-10-01

    Full Text Available Abstract Crimean-Congo haemorrhagic fever (CCHF is an often fatal viral infection described in about 30 countries around the world. The authors report a fatal case of Crimean-Congo hemorrhagic fever (CCHF observed in a patient from Kosova. The diagnosis of CCHF was confirmed by reverse transcription-PCR. Late diagnosis decreased the efficacy of treatment and patient died due to severe complications of infection.

  12. Democratic Republic of Congo A Fertile Ground for Instability in the Great Lakes Region States

    Science.gov (United States)

    2017-06-09

    ravaged by a brutal armed conflict. In comparison to the three past presidents, Joseph Kabila has managed to restore political stability and calm to much...DEMOCRATIC REPUBLIC OF CONGO-A FERTILE GROUND FOR INSTABILITY IN THE GREAT LAKES REGION STATES A thesis presented to the Faculty of...From - To) AUG 2016 – JUNE 2017 4. TITLE AND SUBTITLE Democratic Republic of Congo-A Fertile Ground for Instability in the Great Lakes Region

  13. Tropical Diabetic Hand Syndrome

    African Journals Online (AJOL)

    2015 Annals of Medical and Health Sciences Research | Published by Wolters Kluwer - Medknow. 473. Introduction ... diabetes.[2,3] Tropical diabetic hand syndrome is a terminology .... the importance of seeking medical attention immediately.

  14. Malaria and Tropical Travel

    Centers for Disease Control (CDC) Podcasts

    Malaria is a serious mosquito-borne disease that can lead to death. This podcast discusses malaria risk when traveling to tropical areas, as well as how to protect yourself and your family from malaria infection.

  15. GARP Atlantic Tropical Experiment

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The GARP Atlantic Tropical Experiment (GATE) was the first major international experiment of the Global Atmospheric Research Program (GARP). It was conducted over...

  16. Lightning climatology in the Congo Basin: detailed analysis

    Science.gov (United States)

    Soula, Serge; Kigotsi, Jean; Georgis, Jean-François; Barthe, Christelle

    2016-04-01

    The lightning climatology of the Congo Basin including several countries of Central Africa is analyzed in detail for the first time. It is based on World Wide Lightning Location Network (WWLLN) data for the period from 2005 to 2013. A comparison of these data with the Lightning Imaging Sensor (LIS) data for the same period shows the WWLLN detection efficiency (DE) in the region increases from about 1.70 % in the beginning of the period to 5.90 % in 2013, relative to LIS data, but not uniformly over the whole 2750 km × 2750 km area. Both the annual flash density and the number of stormy days show sharp maximum values localized in eastern of Democratic Republic of Congo (DRC) and west of Kivu Lake, regardless of the reference year and the period of the year. These maxima reach 12.86 fl km-2 and 189 days, respectively, in 2013, and correspond with a very active region located at the rear of the Virunga mountain range characterised with summits that can reach 3000 m. The presence of this range plays a role in the thunderstorm development along the year. The estimation of this local maximum of the lightning density by taking into account the DE, leads to a value consistent with that of the global climatology by Christian et al. (2003) and other authors. Thus, a mean maximum value of about 157 fl km-2 y-1 is found for the annual lightning density. The zonal distribution of the lightning flashes exhibits a maximum between 1°S and 2°S and about 56 % of the flashes located below the equator in the 10°S - 10°N interval. The diurnal evolution of the flash rate has a maximum between 1400 and 1700 UTC, according to the reference year, in agreement with previous works in other regions of the world.

  17. Phyllosilicate weathering pathways in chlorite-talc bearing soil parent materials, D.R. Congo: early findings.

    Science.gov (United States)

    Dumon, Mathijs; Oostermeyer, Fran; Timmermans, Els; De Meulemeester, Aschwin; Mees, Florias; Van Driessche, Isabel; Erens, Hans; Bazirake Mujinya, Basile; Van Ranst, Eric

    2015-04-01

    The study of the formation and transformation of clay minerals is of the upmost importance to understand soil formation and to adjust land-use management to the land surface conditions. These clay minerals determine to a large extent the soil physical and chemical properties. It is commonly observed that over time the mineralogy of any parent material is transformed to a simple assemblage composed mostly of Al and Fe oxides and low-activity clays, e.g. kaolinite. This is especially obvious in the humid tropics, which have been protected from glacial erosion, allowing deep, highly weathered soils to form. Despite the abundant presence of kaolinite in these soils, its formation pathways are still under debate: either neoformation by dissolution-crystallisation reactions or solid-state transformation of 2:1 phyllosilicates. To elucidate this, weathering sequences in a unique 40 m core taken below a termite mound, reaching a talc-chlorite bearing substrate in the Lubumbashi area, Katanga, DR Congo are being investigated in detail using a.o. quantitative X-ray diffraction analysis, chemical characterization, micromorphology and µXRF-scanning with the main objective to improve the understanding of the formation pathways of kaolinite subgroup minerals in humid tropical environments. Based on an initial characterization of the core, two zones of interest were selected for more detailed analysis, for which the early findings will be presented. The first zone extends from ca. 9 m to 11 m below the surface is dominated by kaolinite but shows early traces of primary talc and micas. The second zone extends from 34 to 36 m below the surface and contains large amounts of chlorite, with smaller amounts of talc, micas and kaolinite.

  18. [Approach to sexuality in an AIDS context in Congo].

    Science.gov (United States)

    Courtois, R; Mullet, E; Malvy, D

    2001-01-01

    The pandemic due to the human immunodeficiency virus (HIV) is extensive in Sub-Saharan Africa and especially in Congo. Congo is a small country on the Atlantic coast and characterized by plentiful equatorial forests and low population density (essentially urban). In Congo, there is a high prevalence of HIV. The social and economic consequences of AIDS add to those of a recent civil war in 1997. There were fratricidal confrontations before and after this period. These confrontations have led to a massive exodus of the inhabitants of the capital, Brazzaville, to the forests and neighbouring cities, essentially towards Pointe-Noire. Pointe-Noire, chief place of the region of Kouilou, in the South of the country, is the second city of Congo and the economic Capital. It is undoubtedly for this reason that it has been globally saved. In this context, a sanitary policy of prevention of sexual risky behavior can appear as a challenge. While it supposes a better knowledge of the sexual activity of the young people, it cannot be dissociated from the analysis of the other factors. These factors can be of socio-economic political or cultural order. Thus the influence of cultural variables in the field of sexuality is certainly preponderant in African countries, where sexuality is taboo. Sexuality is a private matter (personal intimacy and the couple), but concerns also the family (in the sense of membership in an extended domestic group or in a system of relationship) in its aspects related to procreation and to the social field (power, alliances). Such individual behaviour can be lived as a questioning of the social order. In this article, the authors question the place of sexuality in Congo, particularly based on the work of anthropologists [2, 6, 7, 9]. Research in the field of sexuality at adolescence is rather recent in France and investigations that have been done in Congo these last ten years do not exist. Meetings and exchanges in 1998 with high-school pupils and

  19. Use and limitations of malaria rapid diagnostic testing by community health workers in war-torn Democratic Republic of Congo.

    Science.gov (United States)

    Hawkes, Michael; Katsuva, Jean Paul; Masumbuko, Claude K

    2009-12-23

    Accurate and practical malaria diagnostics, such as immunochromatographic rapid diagnostic tests (RDTs), have the potential to avert unnecessary treatments and save lives. Volunteer community health workers (CHWs) represent a potentially valuable human resource for expanding this technology to where it is most needed, remote rural communities in sub-Saharan Africa with limited health facilities and personnel. This study reports on a training programme for CHWs to incorporate RDTs into their management strategy for febrile children in the Democratic Republic of Congo, a tropical African setting ravaged by human conflict. Prospective cohort study, satisfaction questionnaire and decision analysis. Twelve CHWs were trained to safely and accurately perform and interpret RDTs, then successfully implemented rapid diagnostic testing in their remote community in a cohort of 357 febrile children. CHWs were uniformly positive in evaluating RDTs for their utility and ease of use. However, high malaria prevalence in this cohort (93% by RDTs, 88% by light microscopy) limited the cost-effectiveness of RDTs compared to presumptive treatment of all febrile children, as evidenced by findings from a simplified decision analysis. CHWs can safely and effectively use RDTs in their management of febrile children; however, cost-effectiveness of RDTs is limited in zones of high malaria prevalence.

  20. Use and limitations of malaria rapid diagnostic testing by community health workers in war-torn Democratic Republic of Congo

    Directory of Open Access Journals (Sweden)

    Katsuva Jean

    2009-12-01

    Full Text Available Abstract Background Accurate and practical malaria diagnostics, such as immunochromatographic rapid diagnostic tests (RDTs, have the potential to avert unnecessary treatments and save lives. Volunteer community health workers (CHWs represent a potentially valuable human resource for expanding this technology to where it is most needed, remote rural communities in sub-Saharan Africa with limited health facilities and personnel. This study reports on a training programme for CHWs to incorporate RDTs into their management strategy for febrile children in the Democratic Republic of Congo, a tropical African setting ravaged by human conflict. Methods Prospective cohort study, satisfaction questionnaire and decision analysis. Results Twelve CHWs were trained to safely and accurately perform and interpret RDTs, then successfully implemented rapid diagnostic testing in their remote community in a cohort of 357 febrile children. CHWs were uniformly positive in evaluating RDTs for their utility and ease of use. However, high malaria prevalence in this cohort (93% by RDTs, 88% by light microscopy limited the cost-effectiveness of RDTs compared to presumptive treatment of all febrile children, as evidenced by findings from a simplified decision analysis. Conclusions CHWs can safely and effectively use RDTs in their management of febrile children; however, cost-effectiveness of RDTs is limited in zones of high malaria prevalence.

  1. A serological survey of Crimean-Congo haemorrhagic fever in animals in the Sharkia Governorate of Egypt

    Directory of Open Access Journals (Sweden)

    Amr Murad

    2008-09-01

    Full Text Available A surveillance survey was conducted over a period of 12 months between September 2004 and August 2005 by the Tropical Medicine Department of Zagazig University in collaboration with Naval Medical Research Unit No. 3 (NAMRU-3, Egypt, to evaluate the role of ruminants as a reservoir host for Crimean-Congo haemorrhagic fever virus (CCHFV. A total of 1 022 serum samples from 313 cattle, 264 water buffalo (Bubalus bubalis, 270 sheep and 175 goats were included in the survey. All samples were collected from the Sharkia Governorate of Egypt and were examined for anti-CCHFV IgG. Of the total of 1 022 samples examined, 32 (3.13% were positive to IgG ELISA. Out of 270 sheep examined, 17 (6.30% were confirmed to have anti-CCHFV IgG with the highest titre recorded at 1:800. However, CCHFV-specific IgG-positive cases among the cattle, buffalo and goats were 3.83%, 0.38% and 1.14%, respectively. Positive cases in age group B (=2 years old were significantly higher (p<0.001 than those in age group A (<2 years old (5.7% versus 1.6%. Belbis City was found to have the highest number of positive cases compared to all other localities (p<0.001.

  2. Characterization of Terrestrial Water Dynamics in the Congo Basin Using GRACE and Satellite Radar Altimetry

    Science.gov (United States)

    Lee, Lyongki; Beighley, R. Edward; Alsdorf, Douglas; Jung, Hahn Chul; Shum, C. K.; Duan, Jianbin; Guo, Junyi; Yamazaki, Dai; Andreadis, Konstantinos

    2011-01-01

    The Congo Basin is the world's third largest in size (approximately 3.7 million km^2), and second only to the Amazon River in discharge (approximately 40,200 cms annual average). However, the hydrological dynamics of seasonally flooded wetlands and floodplains remains poorly quantified. Here, we separate the Congo wetland into four 3 degree x 3 degree regions, and use remote sensing measurements (i.e., GRACE, satellite radar altimeter, GPCP, JERS-1, SRTM, and MODIS) to estimate the amounts of water filling and draining from the Congo wetland, and to determine the source of the water. We find that the amount of water annually filling and draining the Congo wetlands is 111 km^3, which is about one-third the size of the water volumes found on the mainstem Amazon floodplain. Based on amplitude comparisons among the water volume changes and timing comparisons among their fluxes, we conclude that the local upland runoff is the main source of the Congo wetland water, not the fluvial process of river-floodplain water exchange as in the Amazon. Our hydraulic analysis using altimeter measurements also supports our conclusion by demonstrating that water surface elevations in the wetlands are consistently higher than the adjacent river water levels. Our research also highlights differences in the hydrology and hydrodynamics between the Congo wetland and the mainstem Amazon floodplain.

  3. ADSORPSI CONGO RED PADA HUMIN HASIL ISOLASI DARI TANAH HUTAN DAMAR BATURRADEN PURWOKERTO

    Directory of Open Access Journals (Sweden)

    Roy Andreas

    2008-05-01

    Full Text Available Congo red is one of dyes-stuff in textile industry wastwater. If it is thrown directly without waste management process, the dyes could pollute environtment, especially soil. Humin has OH phenolic and carboxylic functional group which can interacted with congo red. The aim of this study is recognize humin characteristic from the soil of Baturraden resin forest, determine the adsorption capacity and isotherm adsorption pattern of congo red by humin from the soil of Baturraden resin forest. Humin in this study is isolated from the soil of Baturraden resin forest. soil cleared of gravel and dirt, then it extracted by using NaOH of nitrogen atmosphere and purified to applies mixture HCl:HF. Humin that is obtained is used to be interacted with dyes with various contact time, various of pH and concentration of congo red so that the adsorption capacities and isotherm adsorption pattern can be obtained. Result of the study showed that the humin has water content 34.92 %, dust content 8.64 %, total acidity 475 cmol/Kg, carboxylic rate 272.5 cmol/Kg, and OH Phenolic rate 202.5 cmol/Kg. The optimum contact time of congo red adsorption by humin is 40 minutes, with optimum pH is 7, adsorption capacities 57.14 mg/g and isotherm adsorption pattern of congo red by humin is follow the pattern of Langmuir isotherm adsorption.

  4. Implications of changes in tropical shifting cultivation intensification on land productivity and GHG-related biogeochemistry

    Science.gov (United States)

    Bustier, Bernard; Ngoy, Alfred; Pietsch, Stephan; Mosnier, Aline

    2017-04-01

    Traditional shifting cultivation used to be a sustainable type of land use for the subsistence of populations in tropical rainforests. The vast resource of moist tropical forests together with low population densities allowed for long fallow periods on sparsely distributed slash and burn parcels with large areas of untouched forest in between. Population growth and concomitant increase in land demand for subsistence as well as increasing infrastructure development for commercial forestry, cash crops and mining, however, altered the picture over recent decades. As a result, fallow periods were reduced due to lack of pristine land. In this study we use field data and modeling results from the Congo Basin to assess the impacts of reduced fallow periods on Carbon sequestration dynamics using a BGC model calibrated and validated with > 150 research plots distributed over the western Congo Basin and representing different management and land use histories. We find that the average carbon sequestration rate reduces over the number of cultivation cycles and that a reduction of the fallow from 10 years to 7 years reduce the average carbon sequestration between 13 and 21% and from 7 years to 4 years between 23 and 29% depending on soil fertility. Results will be discussed in the context of population growth and changes in environmetal conditions.

  5. Pneumonia in the tropics.

    Science.gov (United States)

    Lim, Tow Keang; Siow, Wen Ting

    2018-01-01

    Pneumonia in the tropics poses a heavy disease burden. The complex interplay of climate change, human migration influences and socio-economic factors lead to changing patterns of respiratory infections in tropical climate but also increasingly in temperate countries. Tropical and poorer countries, especially South East Asia, also bear the brunt of the global tuberculosis (TB) pandemic, accounting for almost one-third of the burden. But, as human migration patterns evolve, we expect to see more TB cases in higher income as well as temperate countries, and rise in infections like scrub typhus from ecotourism activities. Fuelled by the ease of air travel, novel zoonotic infections originating from the tropics have led to global respiratory pandemics. As such, clinicians worldwide should be aware of these new conditions as well as classical tropical bacterial pneumonias such as melioidosis. Rarer entities such as co-infections of leptospirosis and chikungunya or dengue will need careful consideration as well. In this review, we highlight aetiologies of pneumonia seen more commonly in the tropics compared with temperate regions, their disease burden, variable clinical presentations as well as impact on healthcare delivery. © 2017 Asian Pacific Society of Respirology.

  6. Neglected tropical diseases outside the tropics.

    Directory of Open Access Journals (Sweden)

    Francesca F Norman

    Full Text Available BACKGROUND: The neglected tropical diseases (NTDs cause significant morbidity and mortality worldwide. Due to the growth in international travel and immigration, NTDs may be diagnosed in countries of the western world, but there has been no specific focus in the literature on imported NTDs. METHODS: Retrospective study of a cohort of immigrants and travelers diagnosed with one of the 13 core NTDs at a Tropical Medicine Referral Unit in Spain during the period April 1989-December 2007. Area of origin or travel was recorded and analyzed. RESULTS: There were 6168 patients (2634 immigrants, 3277 travelers and 257 VFR travelers in the cohort. NTDs occurred more frequently in immigrants, followed by VFR travelers and then by other travelers (p<0.001 for trend. The main NTDs diagnosed in immigrants were onchocerciasis (n = 240, 9.1% acquired mainly in sub-Saharan Africa, Chagas disease (n = 95, 3.6% in immigrants from South America, and ascariasis (n = 86, 3.3% found mainly in immigrants from sub-Saharan Africa. Most frequent NTDs in travelers were: schistosomiasis (n = 43, 1.3%, onchocerciasis (n = 17, 0.5% and ascariasis (n = 16, 0.5%, and all were mainly acquired in sub-Saharan Africa. The main NTDs diagnosed in VFR travelers were onchocerciasis (n = 14, 5.4%, and schistosomiasis (n = 2, 0.8%. CONCLUSIONS: The concept of imported NTDs is emerging as these infections acquire a more public profile. Specific issues such as the possibility of non-vectorial transmission outside endemic areas and how some eradication programmes in endemic countries may have an impact even in non-tropical western countries are addressed. Recognising NTDs even outside tropical settings would allow specific prevention and control measures to be implemented and may create unique opportunities for research in future.

  7. Wild western lowland gorillas signal selectively using odor.

    Directory of Open Access Journals (Sweden)

    Michelle Klailova

    Full Text Available Mammals communicate socially through visual, auditory and chemical signals. The chemical sense is the oldest sense and is shared by all organisms including bacteria. Despite mounting evidence for social chemo-signaling in humans, the extent to which it modulates behavior is debated and can benefit from comparative models of closely related hominoids. The use of odor cues in wild ape social communication has been only rarely explored. Apart from one study on wild chimpanzee sniffing, our understanding is limited to anecdotes. We present the first study of wild gorilla chemo-communication and the first analysis of olfactory signaling in relation to arousal levels and odor strength in wild apes. If gorilla scent is used as a signaling mechanism instead of only a sign of arousal or stress, odor emission should be context specific and capable of variation as a function of the relationships between the emitter and perceiver(s. Measured through a human pungency scale, we determined the factors that predicted extreme levels of silverback odor for one wild western lowland gorilla (Gorilla gorilla gorilla group silverback. Extreme silverback odor was predicted by the presence and intensity of inter-unit interactions, silverback anger, distress and long-calling auditory rates, and the absence of close proximity between the silverback and mother of the youngest infant. Odor strength also varied according to the focal silverback's strategic responses during high intensity inter-unit interactions. Silverbacks appear to use odor as a modifiable form of communication; where odor acts as a highly flexible, context dependent signaling mechanism to group members and extra-group units. The importance of olfaction to ape social communication may be especially pertinent in Central African forests where limited visibility may necessitate increased reliance on other senses.

  8. Geological setting control of flood dynamics in lowland rivers (Poland).

    Science.gov (United States)

    Wierzbicki, Grzegorz; Ostrowski, Piotr; Falkowski, Tomasz; Mazgajski, Michał

    2018-04-27

    We aim to answer a question: how does the geological setting affect flood dynamics in lowland alluvial rivers? The study area covers three river reaches: not trained, relatively large on the European scale, flowing in broad valleys cut in the landscape of old glacial plains. We focus on the locations where levees [both: a) natural or b) artificial] were breached during flood. In these locations we identify (1) the erosional traces of flood (crevasse channels) on the floodplain displayed on DEM derived from ALS LIDAR. In the main river channel, we perform drillings in order to measure the depth of the suballuvial surface and to locate (2) the protrusions of bedrock resistant to erosion. We juxtapose on one map: (1) the floodplain geomorphology with (2) the geological data from the river channel. The results from each of the three study reaches are presented on maps prepared in the same manner in order to enable a comparison of the regularities of fluvial processes written in (1) the landscape and driven by (2) the geological setting. These processes act in different river reaches: (a) not embanked and dominated by ice jam floods, (b) embanked and dominated by rainfall and ice jam floods. We also analyse hydrological data to present hydrodynamic descriptions of the flood. Our principal results indicate similarity of (1) distinctive erosional patterns and (2) specific geological features in all three study reaches. We draw the conclusion: protrusions of suballuvial bedrock control the flood dynamics in alluvial rivers. It happens in both types of rivers. In areas where the floodplain remains natural, the river inundates freely during every flood. In other areas the floodplain has been reclaimed by humans who constructed an artificial levee system, which protects the flood-prone area from inundation, until levee breach occurs. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Specific Vicariance of Two Primeval Lowland Forest Lichen Indicators

    Science.gov (United States)

    Kubiak, Dariusz; Osyczka, Piotr

    2017-06-01

    To date, the lichens Chrysothrix candelaris and Varicellaria hemisphaerica have been classified as accurate primeval lowland forest indicators. Both inhabit particularly valuable remnants of oak-hornbeam forests in Europe, but tend toward a specific kind of vicariance on a local scale. The present study was undertaken to determine habitat factors responsible for this phenomenon and verify the indicative and conservation value of these lichens. The main spatial and climatic parameters that, along with forest structure, potentially affect their distribution patterns and abundance were analysed in four complexes with typical oak-hornbeam stands in NE Poland. Fifty plots of 400 m2 each were chosen for detailed examination of stand structure and epiphytic lichens directly associated with the indicators. The study showed that the localities of the two species barely overlap within the same forest community in a relatively small geographical area. The occurrence of Chrysothrix candelaris depends basically only on microhabitat space provided by old oaks and its role as an indicator of the ecological continuity of habitat is limited. Varicellaria hemisphaerica is not tree specific but a sufficiently high moisture of habitat is essential for the species and it requires forests with high proportion of deciduous trees in a wide landscape scale. Local landscape-level habitat continuity is more important for this species than the current age of forest stand. Regardless of the indicative value, localities of both lichens within oak-hornbeam forests deserve the special protection status since they form unique assemblages of exclusive epiphytes, including those with high conservation value.

  10. Seasonal dynamics in photosynthesis of woody plants at the northern limit of Asian tropics: potential role of fog in maintaining tropical rainforests and agriculture in Southwest China.

    Science.gov (United States)

    Zhang, Yong-Jiang; Holbrook, N Michele; Cao, Kun-Fang

    2014-10-01

    The lowland tropical rainforests in Xishuangbanna, Southwest (SW) China, mark the northern limit of Asian tropics. Fog has been hypothesized to play a role in maintaining rainforests and tropical crop production in this region, but the physiological mechanism has not been studied. The goals of this study were to characterize the seasonal dynamics in photosynthesis and to assess the potential for fog to mitigate chilling-induced photodamage for tropical trees and crops in Xishuangbanna. We measured seasonal dynamics in light-saturated net photosynthetic rate (Aa), stomatal conductance (gs), intercellular CO2 concentration, quantum yield of Photosystem II (Fv/Fm) and maximum P700 changes (Pm; indicates the amount of active PSI complex), as well as chilling resistance and fog (light/shading) effects on low temperature-induced decline in Fv/Fm and Pm for native tree and introduced lower latitude tree or woody shrub species grown in a tropical botanical garden. Despite significant decreases in Aa, gs, Pm and Fv/Fm, most species maintained considerably high Aa during the cool season (2.51-14.6 μmol m(-2) s(-1)). Shaded leaves exposed to seasonal low temperatures had higher Fv/Fm than sun-exposed leaves in the cool season. All species could tolerate 1.4 °C in the dark, whereas a combined treatment of low temperature and high light caused a distinctly faster decline in Pm and Fv/Fm compared with low temperature treatment alone. Because fog persistence avoids or shortens the duration of high light condition in the morning when the temperatures are still low, our results provide support for the hypothesis that fog reduces chilling damage to tropical plants in this region and thus plays a role in maintaining tropical rainforests and agriculture in SW China. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Nitrogen utilisation of lowland cauliflower grown on coconut coir dust

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Asiah

    2004-07-01

    Strong wind, high rainfall, the spread of diseases during rainy season and pests problems in open field agriculture have led to the current trend in growing vegetables under protected environment. The occurrence of soil borne disease, and limited suitable land for agriculture are some of the reasons to look for alternative media such as coconut coir dust. The basic properties of coconut coir dust as a soil less growing medium and the utilisation of nitrogen (n) fertiliser for the lowland cauliflower grown in them have not been thoroughly investigated and are therefore not well understood. This study has been conducted by the need to provide a basis for determining optimal levels/ concentration and forms of nitrogen supply, and by the need to minimize environmental consequences of lowland cauliflower production. It focuses on the effects of N supply in terms of different levels of N and ionic N forms in the nutrient solution, on the growth, development and N utilisation of cauliflower grown in coconut coir dust under greenhouse condition in the lowlands. Based on the plant growth parameters studied coconut coir dust was found to be more suitable than oil palm empty fruit bunch as a growing medium. From the growth and development study using coconut coir dust, it can be deduced that the N requirement by the plant is less at later growth stage regardless of low or high level of N in the nutrient solution. However, low level of N of 50 mg l{sup -1} was found to be inadequate for plant growth and curd yield. The N concentration levels of 200 mg l{sup -1} in the nutrient solution optimised both the vegetative and curd production. A somewhat lower level of N (170 mg l{sup -1}) produced curd weight not significantly different from N level of 200 mg l{sup -1}. The plant growth and curd yield was reduced by about 29.0 % at 400 mg N l{sup -1}. The N level of 400 mg l{sup -1} in the nutrient solution may be in excess to that actually required by the plant, resulting in a high

  12. Nitrogen utilisation of lowland cauliflower grown on coconut coir dust

    International Nuclear Information System (INIS)

    Asiah Ahmad

    2004-01-01

    Strong wind, high rainfall, the spread of diseases during rainy season and pests problems in open field agriculture have led to the current trend in growing vegetables under protected environment. The occurrence of soil borne disease, and limited suitable land for agriculture are some of the reasons to look for alternative media such as coconut coir dust. The basic properties of coconut coir dust as a soil less growing medium and the utilisation of nitrogen (n) fertiliser for the lowland cauliflower grown in them have not been thoroughly investigated and are therefore not well understood. This study has been conducted by the need to provide a basis for determining optimal levels/ concentration and forms of nitrogen supply, and by the need to minimize environmental consequences of lowland cauliflower production. It focuses on the effects of N supply in terms of different levels of N and ionic N forms in the nutrient solution, on the growth, development and N utilisation of cauliflower grown in coconut coir dust under greenhouse condition in the lowlands. Based on the plant growth parameters studied coconut coir dust was found to be more suitable than oil palm empty fruit bunch as a growing medium. From the growth and development study using coconut coir dust, it can be deduced that the N requirement by the plant is less at later growth stage regardless of low or high level of N in the nutrient solution. However, low level of N of 50 mg l -1 was found to be inadequate for plant growth and curd yield. The N concentration levels of 200 mg l -1 in the nutrient solution optimised both the vegetative and curd production. A somewhat lower level of N (170 mg l -1 ) produced curd weight not significantly different from N level of 200 mg l -1 . The plant growth and curd yield was reduced by about 29.0 % at 400 mg N l -1 . The N level of 400 mg l -1 in the nutrient solution may be in excess to that actually required by the plant, resulting in a high unused N nutrient

  13. Nutrient additions to a tropical rain forest drive substantial soil carbon dioxide losses to the atmosphere.

    Science.gov (United States)

    Cleveland, Cory C; Townsend, Alan R

    2006-07-05

    Terrestrial biosphere-atmosphere carbon dioxide (CO(2)) exchange is dominated by tropical forests, where photosynthetic carbon (C) uptake is thought to be phosphorus (P)-limited. In P-poor tropical forests, P may also limit organic matter decomposition and soil C losses. We conducted a field-fertilization experiment to show that P fertilization stimulates soil respiration in a lowland tropical rain forest in Costa Rica. In the early wet season, when soluble organic matter inputs to soil are high, P fertilization drove large increases in soil respiration. Although the P-stimulated increase in soil respiration was largely confined to the dry-to-wet season transition, the seasonal increase was sufficient to drive an 18% annual increase in CO(2) efflux from the P-fertilized plots. Nitrogen (N) fertilization caused similar responses, and the net increases in soil respiration in response to the additions of N and P approached annual soil C fluxes in mid-latitude forests. Human activities are altering natural patterns of tropical soil N and P availability by land conversion and enhanced atmospheric deposition. Although our data suggest that the mechanisms driving the observed respiratory responses to increased N and P may be different, the large CO(2) losses stimulated by N and P fertilization suggest that knowledge of such patterns and their effects on soil CO(2) efflux is critical for understanding the role of tropical forests in a rapidly changing global C cycle.

  14. Growth response and acclimation of CO2 exchange characteristics to elevated temperatures in tropical tree seedlings.

    Science.gov (United States)

    Cheesman, Alexander W; Winter, Klaus

    2013-09-01

    Predictions of how tropical forests will respond to future climate change are constrained by the paucity of data on the performance of tropical species under elevated growth temperatures. In particular, little is known about the potential of tropical species to acclimate physiologically to future increases in temperature. Seedlings of 10 neo-tropical tree species from different functional groups were cultivated in controlled-environment chambers under four day/night temperature regimes between 30/22 °C and 39/31 °C. Under well-watered conditions, all species showed optimal growth at temperatures above those currently found in their native range. While non-pioneer species experienced catastrophic failure or a substantially reduced growth rate under the highest temperature regime employed (i.e. daily average of 35 °C), growth in three lowland pioneers showed only a marginal reduction. In a subsequent experiment, three species (Ficus insipida, Ormosia macrocalyx, and Ochroma pyramidale) were cultivated at two temperatures determined as sub- and superoptimal for growth, but which resulted in similar biomass accumulation despite a 6°C difference in growth temperature. Through reciprocal transfer and temperature adjustment, the role of thermal acclimation in photosynthesis and respiration was investigated. Acclimation potential varied among species, with two distinct patterns of respiration acclimation identified. The study highlights the role of both inherent temperature tolerance and thermal acclimation in determining the ability of tropical tree species to cope with enhanced temperatures.

  15. The influence of Congo River discharges in the surface and deep layers of the Gulf of Guinea

    OpenAIRE

    Vangriesheim, A.; Pierre, C.; Aminot, A.; Metzl, N.; Baurand, François; Caprais, J. C.

    2009-01-01

    The main feature of the Congo-Angola margin in the Gulf of Guinea is the Congo (ex-Zaire) deep-sea fan composed of a submarine canyon directly connected to the Congo River, a channel and a [sediment] lobe area. During the multi-disciplinary programme called BIOZAIRE conducted by Ifremer from 2000 to 2005, two CTD-O2 sections with discrete water column samples were performed (BIOZAIRE3 cruise: 2003-2004) to study the influence of the Congo River discharges, both in the surface layer and in the...

  16. Tropical Agroecosystems: These habitats are misunderstood by the temperate zones, mismanaged by the tropics.

    Science.gov (United States)

    Janzen, D H

    1973-12-21

    I have listed some of the ways in which the lowland tropics are not such a warm and wonderful place for the farmer, some of the reasons why it may be unreasonable to expect him to cope with the problems, and some of the ways in which the temperate zones make his task more difficult. The tropics are very close to being a tragedy of the commons on a global scale (69, 103), and it is the temperate zone's shepherds and sheep who are among the greatest offenders (31). Given that the temperate zones have some limited amount of resources with which they are willing to repay the tropics, how can these resources best be spent? The first answer, without doubt, is education, and the incorporation of what is already known about the tropics into that education. Second should be the generation of secure psychological and physical resources for governments that show they are enthusiastic about the development of an SYTA. Third should be support of intensive research needed to generate the set of site-specific rules for specific, clearly identified SYTA's. The subject matter of youths' cultural programming is presumably determined by what they will need during the rest of their lives. A major component of this programming should be the teaching of the socioeconomic rules of a sustained-yield, nonexpanding economy, tuned to the concept of living within the carrying capacity of the country's or region's resources. Incorporating such a process into tropical school systems will cause a major upheaval, if for no other reason than that it will involve an evaluation of the country's resources, what standard of living is to be accepted by those living on them, and who is presently harvesting them. Of even greater impact, it will have to evaluate resources in terms of their ability to raise the standard of living by Y amount for X proportion of the people in the region, rather than in terms of their cash value on the world market. For such a change to be technologically successful, it will

  17. An ongoing hydro-biogeochemical characterization of a partly drained lowland in a clay till subcatchment

    DEFF Research Database (Denmark)

    Prinds, Christian; Petersen, Rasmus Jes; Iversen, Bo Vangsø

    2016-01-01

    as well as novel approaches e.g. remote sensing using UAV’s (Unmanned Aerial Vehicles commonly known as drones), a newly developed redox probe, and novel uses of geophysical methods. More information about TReNDS can be found at www.nitrat.dk. The project is funded by Innovation Fund Denmark......Riparian lowlands may have significant impact on the catchment nitrate balance. As a part of the strategic research project TReNDS (“Transport and reduction of nitrate in Danish landscapes at various scales”) extensive field investigations have commenced in the Fensholt subcatchment situated within...... Norsminde Fjord catchment, Odder, Denmark. The riparian lowlands are surrounded by a hilly landscape composed of mainly clayey till, and hence the landscape is heavily drained. Drainpipes are either disconnected at the hillslope bordering the riparian lowland or discharging partly through the riparian zone...

  18. Dispersal and colonisation of plants in lowland streams: success rates and bottlenecks

    DEFF Research Database (Denmark)

    Riis, Tenna

    2008-01-01

    -rich lowland streams. Rather, I conclude that primary colonisation is the main constraint to regaining vegetation in lowland streams in general and in vegetation-free rehabilitated streams in particular. Therefore, if plant colonisation is a target for stream rehabilitation, it is important to enhance......Plant dispersal and colonisation, including rates of dispersal, retention, colonisation and survival of dispersed propagules (shoots and seeds), were studied in a 300-m stream reach in a macrophyte-rich lowland stream during one growing season. Relationships between colonisation processes...... and simple flow parameters were tested. Each fortnight during a growing season, the number of dispersed plant propagules and the number of new and lost plant colonisations since the last sampling day were recorded. The retention of dispersing shoots was tested on two occasions during the growing season...

  19. A comprehensive assessment of agriculture in lowlands of south Brazil: characterization and comparison of current and alternative concepts

    NARCIS (Netherlands)

    Theisen, Giovani

    2017-01-01

    Agriculture in the lowlands of south Brazil is of strategic importance at the national level, since it supplies around 80% of the rice consumed by the Brazilian population. In Rio Grande do Sul, the southernmost state in Brazil, three million hectares of lowlands are ready for grain-based

  20. Impacts of land leveling on lowland soil physical properties

    Directory of Open Access Journals (Sweden)

    José Maria Barbat Parfitt

    2014-02-01

    Full Text Available The practice of land leveling alters the soil surface to create a uniform slope to improve land conditions for the application of all agricultural practices. The aims of this study were to evaluate the impacts of land leveling through the magnitudes, variances and spatial distributions of selected soil physical properties of a lowland area in the State of Rio Grande do Sul, Brazil; the relationships between the magnitude of cuts and/or fills and soil physical properties after the leveling process; and evaluation of the effect of leveling on the spatial distribution of the top of the B horizon in relation to the soil surface. In the 0-0.20 m layer, a 100-point geo-referenced grid covering two taxonomic soil classes was used in assessment of the following soil properties: soil particle density (Pd and bulk density (Bd; total porosity (Tp, macroporosity (Macro and microporosity (Micro; available water capacity (AWC; sand, silt, clay, and dispersed clay in water (Disp clay contents; electrical conductivity (EC; and weighted average diameter of aggregates (WAD. Soil depth to the top of the B horizon was also measured before leveling. The overall effect of leveling on selected soil physical properties was evaluated by paired "t" tests. The effect on the variability of each property was evaluated through the homogeneity of variance test. The thematic maps constructed by kriging or by the inverse of the square of the distances were visually analyzed to evaluate the effect of leveling on the spatial distribution of the properties and of the top of the B horizon in relation to the soil surface. Linear regression models were fitted with the aim of evaluating the relationship between soil properties and the magnitude of cuts and fills. Leveling altered the mean value of several soil properties and the agronomic effect was negative. The mean values of Bd and Disp clay increased and Tp, Macro and Micro, WAD, AWC and EC decreased. Spatial distributions of all

  1. Isotopically exchangeable Al in coastal lowland acid sulfate soils

    Energy Technology Data Exchange (ETDEWEB)

    Yvanes-Giuliani, Yliane A.M. [UNSW Water Research Centre, School of Civil and Environmental Engineering, UNSW Australia, Sydney, NSW 2052 (Australia); Centre Européen de Recherche et d' Enseignement des Géosciences de l' Environnement, Aix-Marseille Université, Aix en Provence (France); Fink, D. [Centre Européen de Recherche et d' Enseignement des Géosciences de l' Environnement, Aix-Marseille Université, Aix en Provence (France); Rose, J. [Institute for Environmental Research, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Waite, T. David [UNSW Water Research Centre, School of Civil and Environmental Engineering, UNSW Australia, Sydney, NSW 2052 (Australia); Collins, Richard N., E-mail: richard.collins@unsw.edu.au [UNSW Water Research Centre, School of Civil and Environmental Engineering, UNSW Australia, Sydney, NSW 2052 (Australia)

    2016-01-15

    Periodic discharges of high concentrations of aluminium (Al) causing fish kills and other adverse effects occur worldwide in waterways affected by coastal lowland acid sulfate soils (CLASS). The exchangeability — a metal's ability to readily transfer between the soil solid- and solution-phases — of Al in these soils is therefore of particular importance as it has implications for metal transport, plant availability and toxicity to living organisms. In the present study, the concentrations of isotopically exchangeable Al (E values) were measured in 27 CLASS and compared with common salt extractions (i.e. KCl and CuCl{sub 2}) used to estimate exchangeable soil pools of Al. E values of Al were high in the soils, ranging from 357 to 3040 mg·kg{sup −1}. Exchangeable concentrations estimated using 1 M KCl were consistently lower than measured E values, although a reasonable correlation was obtained between the two values (E = 1.68 × Al{sub KCl}, r{sup 2} = 0.66, n = 25). The addition of a 0.2 M CuCl{sub 2} extraction step improved the 1:1 agreement between extractable and isotopically exchangeable Al concentrations, but lead to significant mobilisation of non-isotopically exchangeable Al in surficial ‘organic-rich’ CLASS having E values < 1000 mg·kg{sup −1}. It was concluded that currently used (i.e. 1 M KCl) methodology severely underestimates exchangeable Al and total actual acidity values in CLASS and should be corrected by a factor similar to the one determined here. - Highlights: • Isotopically exchangeable Al was compared to 1 M KCl or 0.2 M CuCl{sub 2} extractable Al. • 1 M KCl always underestimated isotopically exchangeable Al concentrations. • 0.2 M CuCl{sub 2} mobilised non-isotopically exchangeable Al • 1 M KCl values require correction of ~ 1.7 to reflect exchangeable Al concentrations.

  2. Hydroclimatic Change in the Congo River Basin: Past, Present and Future169

    Science.gov (United States)

    Aloysius, N. R.

    2016-12-01

    Tropical regions provide habitat for the world's most diverse fauna and flora, sequester more atmospheric carbon and provide livelihood for millions of people. The hydrological cycle provides vital linkages for maintaining these ecosystem functions, yet, the understanding of its spatiotemporal variability is limited. Research on the hydrological cycle of the Congo River Basin (CRB), which encompasses the second largest rainforests, has been largely ignored. Global Climate Models (GCM) show limited skills in simulating CRB's climate and their future projections vary widely. Yet, GCMs provide the most plausible scenarios of future climate, based upon which changes in hydrologic fluxes can be predicted with the aid hydrological models. In order to address the gaps in knowledge and to highlight the research needs, we i) developed a spatially explicit hydrological model suitable for describing key hydrological processes, ii) evaluated the performance of GCMs in simulating precipitation and temperature in the region, iii) developed a set of climate change scenarios for the CRB and iv) developed a simplified modeling framework to quantify water management options for rain-fed agriculture with the objective of achieving the triple goals of sustainable development: food security, poverty alleviation and ecosystem conservation. The hydrology model, which was validated with observed stream flows at 50 locations, satisfactorily characterizes spatiotemporal variability of key fluxes. Our evaluation of 25 GCM outputs reveal that many GCMs poorly simulate regional precipitation. We implemented a statistical bias-correction method to develop precipitation and temperature projections for two future greenhouse gas emission scenarios. These climate forcings were, then, used to drive the hydrology model. Our results show that the near-term projections are not affected by emission scenarios. However, towards the mid-21st century, projections are emission scenario dependent. Available

  3. Heath Sector Network Governance and State-building in South Kivu, Democratic Republic of Congo.

    Science.gov (United States)

    Bwimana, Aembe

    2017-12-01

    Longstanding patterns of interaction exist between state and non-state actors seeking to improve public health in Democratic Republic of Congo (DRC). DRC is a weak state, and, in many cases, private actors have stepped in to fill the void created by the lack of state health care provision. However, the role of these interactions in creating a governance network in the health sector has been underexplored. Using data from 18 months of qualitative field research, this study aimed to explore governance networks in DRC's health sector, examining how multiple stakeholders work to manage the health system and how the resulting governance network has been relevant for the state-building process. The findings demonstrate that the health sector in South Kivu is emerging as an arena of networked governance based on active partnerships between state institutions and non-state actors. Interactions between state and non-state actors account for the persistence of the health sector in a setting characterized by state weakness. However, networked governance does not function optimally, because, although non-state interventions fill the void where the state falls short, the DRC state has faced the challenge of interacting with partners with fragmented and horizontally competing agendas. Although weak, the shadow of state authority is present in the arena of stakeholders' interactions, as the state plays a determining role by providing a regulatory framework. Overall, the findings show that the interactive engagement of non-state actors contributes to improving institutional capacity through these actors' engagement with state institutions for health system management and institutional development. However, although networked health sector governance does contribute to state capacity, it is difficult to assess the real influence of these interactions on the state-building process in a context of critical fragility, where coordination and alignment have been problematic. © The

  4. Generating daily weather data for ecosystem modelling in the Congo River Basin

    Science.gov (United States)

    Petritsch, Richard; Pietsch, Stephan A.

    2010-05-01

    Daily weather data are an important constraint for diverse applications in ecosystem research. In particular, temperature and precipitation are the main drivers for forest ecosystem productivity. Mechanistic modelling theory heavily relies on daily values for minimum and maximum temperatures, precipitation, incident solar radiation and vapour pressure deficit. Although the number of climate measurement stations increased during the last centuries, there are still regions with limited climate data. For example, in the WMO database there are only 16 stations located in Gabon with daily weather measurements. Additionally, the available time series are heavily affected by measurement errors or missing values. In the WMO record for Gabon, on average every second day is missing. Monthly means are more robust and may be estimated over larger areas. Therefore, a good alternative is to interpolate monthly mean values using a sparse network of measurement stations, and based on these monthly data generate daily weather data with defined characteristics. The weather generator MarkSim was developed to produce climatological time series for crop modelling in the tropics. It provides daily values for maximum and minimum temperature, precipitation and solar radiation. The monthly means can either be derived from the internal climate surfaces or prescribed as additional inputs. We compared the generated outputs observations from three climate stations in Gabon (Lastourville, Moanda and Mouilla) and found that maximum temperature and solar radiation were heavily overestimated during the long dry season. This is due to the internal dependency of the solar radiation estimates to precipitation. With no precipitation a cloudless sky is assumed and thus high incident solar radiation and a large diurnal temperature range. However, in reality it is cloudy in the Congo River Basin during the long dry season. Therefore, we applied a correction factor to solar radiation and temperature range

  5. Tropical Agro-Sciences

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    The Tropical Agro-Sciences Division has two functions: conduct research on the impact of air pollution on tropical agricultural and to provide training to UPR graduate students and visiting scientists. Since the reorientation of the Center's interests under ERDA, the Division has directed its research activities, with particular emphasis on the effects of atmospheric pollution on tropical agriculture in the Guayanilla-Penuelas region, which has a fossil-fuel power plant, petroleum refineries, and associated industries. This new area of research is important to ERDA because the knowledge gained regarding the effects of air pollution related to energy technology on the agricultural environment and productivity will be useful in planning future energy developments. Information about the potential harm of air pollutants to man through the food chain and about ways of alleviating their impact on agriculture are of practical importance. Studies of the mechanisms involved in pollution injury, protection, and tolerance are of basic significance

  6. Gall-forming insects in a lowland tropical rainforest: low species diversity in an extremely specialised quild

    Czech Academy of Sciences Publication Activity Database

    Butterill, Philip T.; Novotný, Vojtěch

    2015-01-01

    Roč. 40, č. 4 (2015), s. 409-419 ISSN 0307-6946 R&D Projects: GA ČR GA13-10486S Grant - others:European Social Fund(CZ) CZ.1.07/2.3.00/20.0064; National Science Foundation(US) DEB 0515678; UK Darwin Initiative for the Survival Species(GB) 14/054 Institutional support: RVO:60077344 Keywords : gall-forming insects * host specificity * Papua New Guinea Subject RIV: EH - Ecology, Behaviour Impact factor: 1.687, year: 2015 http://onlinelibrary.wiley.com/doi/10.1111/een.12198/abstract

  7. Monocot leaves are eaten less than dicot leaves in tropical lowland rain forests: correlations with toughness and leaf presentation

    DEFF Research Database (Denmark)

    Grubb, P.J.; Jackson, R.V.; Barberis, I.M.

    2008-01-01

    . It was hypothesized that (a) losses of leaf area to herbivorous invertebrates are generally greatest during leaf expansion and smaller for monocots than for dicots, and (b) where losses after expansion are appreciable any difference between monocots and dicots then is smaller than that found during expansion. Methods......: At six sites on four continents, estimates were made of lamina area loss from the four most recently mature leaves of focal monocots and of the nearest dicot shoot. Measurements of leaf mass per unit area, and the concentrations of water and nitrogen were made for many of the species. In Panama...... of leaf mass per unit area, or concentrations of water or nitrogen. At only one site was the increase in loss from first to fourth mature leaf significant (also large and the same in monocots and dicots), but the losses sustained during expansion were much smaller in the monocots. In the leaf-cutter ant...

  8. Restoring degraded tropical forests for carbon and biodiversity

    International Nuclear Information System (INIS)

    Budiharta, Sugeng; Meijaard, Erik; Wilson, Kerrie A; Erskine, Peter D; Rondinini, Carlo; Pacifici, Michela

    2014-01-01

    The extensive deforestation and degradation of tropical forests is a significant contributor to the loss of biodiversity and to global warming. Restoration could potentially mitigate the impacts of deforestation, yet knowledge on how to efficiently allocate funding for restoration is still in its infancy. We systematically prioritize investments in restoration in the tropical landscape of East Kalimantan, Indonesia, and through this application demonstrate the capacity to account for a diverse suite of restoration techniques and forests of varying condition. To achieve this we develop a map of forest degradation for the region, characterized on the basis of aboveground biomass and differentiated by broad forest types. We estimate the costs of restoration as well as the benefits in terms of carbon sequestration and improving the suitability of habitat for threatened mammals through time. When the objective is solely to enhance carbon stocks, then restoration of highly degraded lowland forest is the most cost-effective activity. However, if the objective is to improve the habitat of threatened species, multiple forest types should be restored and this reduces the accumulated carbon by up to 24%. Our analysis framework provides a transparent method for prioritizing where and how restoration should occur in heterogeneous landscapes in order to maximize the benefits for carbon and biodiversity. (letter)

  9. Restoring degraded tropical forests for carbon and biodiversity

    Science.gov (United States)

    Budiharta, Sugeng; Meijaard, Erik; Erskine, Peter D.; Rondinini, Carlo; Pacifici, Michela; Wilson, Kerrie A.

    2014-11-01

    The extensive deforestation and degradation of tropical forests is a significant contributor to the loss of biodiversity and to global warming. Restoration could potentially mitigate the impacts of deforestation, yet knowledge on how to efficiently allocate funding for restoration is still in its infancy. We systematically prioritize investments in restoration in the tropical landscape of East Kalimantan, Indonesia, and through this application demonstrate the capacity to account for a diverse suite of restoration techniques and forests of varying condition. To achieve this we develop a map of forest degradation for the region, characterized on the basis of aboveground biomass and differentiated by broad forest types. We estimate the costs of restoration as well as the benefits in terms of carbon sequestration and improving the suitability of habitat for threatened mammals through time. When the objective is solely to enhance carbon stocks, then restoration of highly degraded lowland forest is the most cost-effective activity. However, if the objective is to improve the habitat of threatened species, multiple forest types should be restored and this reduces the accumulated carbon by up to 24%. Our analysis framework provides a transparent method for prioritizing where and how restoration should occur in heterogeneous landscapes in order to maximize the benefits for carbon and biodiversity.

  10. Consistent patterns of high alpha and low beta diversity in tropical parasitic and free-living protists.

    Science.gov (United States)

    Lentendu, Guillaume; Mahé, Frédéric; Bass, David; Rueckert, Sonja; Stoeck, Thorsten; Dunthorn, Micah

    2018-05-30

    Tropical animals and plants are known to have high alpha diversity within forests, but low beta diversity between forests. By contrast, it is unknown whether microbes inhabiting the same ecosystems exhibit similar biogeographic patterns. To evaluate the biogeographies of tropical protists, we used metabarcoding data of species sampled in the soils of three lowland Neotropical rainforests. Taxa-area and distance-decay relationships for three of the dominant protist taxa and their subtaxa were estimated at both the OTU and phylogenetic levels, with presence-absence and abundance-based measures. These estimates were compared to null models. High local alpha and low regional beta diversity patterns were consistently found for both the parasitic Apicomplexa and the largely free-living Cercozoa and Ciliophora. Similar to animals and plants, the protists showed spatial structures between forests at the OTU and phylogenetic levels, and only at the phylogenetic level within forests. These results suggest that the biogeographies of macro- and micro-organismal eukaryotes in lowland Neotropical rainforests are partially structured by the same general processes. However, and unlike the animals and plants, the protist OTUs did not exhibit spatial structures within forests, which hinders our ability to estimate the local and regional diversity of protists in tropical forests. © 2018 John Wiley & Sons Ltd.

  11. 1997 Annual Tropical Cyclone Report

    National Research Council Canada - National Science Library

    Dillon, C

    1997-01-01

    .... Separate bulletins are issued for the Western Pacific and the Indian Ocean. TROPICAL CYCLONE FORMATION ALERT - Defines a specific area when synoptic, satellite, or other germane data indicate development of a significant tropical cyclone (TC...

  12. Trace metal distributions in the sediments from river-reservoir systems: case of the Congo River and Lake Ma Vallée, Kinshasa (Democratic Republic of Congo).

    Science.gov (United States)

    Mwanamoki, Paola M; Devarajan, Naresh; Niane, Birane; Ngelinkoto, Patience; Thevenon, Florian; Nlandu, José W; Mpiana, Pius T; Prabakar, Kandasamy; Mubedi, Josué I; Kabele, Christophe G; Wildi, Walter; Poté, John

    2015-01-01

    The contamination of drinking water resources by toxic metals is a major problem in many parts of the world, particularly in dense populated areas of developing countries that lack wastewater treatment facilities. The present study characterizes the recent evolution with time of some contaminants deposited in the Congo River and Lake Ma Vallée, both located in the vicinity of the large city of Kinshasa, capital of Democratic Republic of Congo (DRC). Physicochemical parameters including grain size distribution, organic matter and trace element concentrations were measured in sediment cores sampled from Congo River (n = 3) and Lake Ma Vallée (n = 2). The maximum concentration of trace elements in sediment profiles was found in the samples from the sites of Pool Malebo, with the values of 107.2, 111.7, 88.6, 39.3, 15.4, 6.1 and 4.7 mg kg(-1) for Cr, Ni, Zn, Cu, Pb, As and Hg, respectively. This site, which is characterized by intense human activities, is especially well known for the construction of numerous boats that are used for regular navigation on Congo River. Concerning Lake Ma Vallée, the concentration of all metals are generally low, with maximum values of 26.3, 53.6, 16.1, 15.3, 6.5 and 1.8 mg kg(-1) for Cr, Ni, Zn, Cu, Pb and As, respectively. However, the comparison of the metal profiles retrieved from the different sampled cores also reveals specific variations. The results of this study point out the sediment pollution by toxic metals in the Congo River Basin. This research presents useful tools for the evaluation of sediment contamination of river-reservoir systems.

  13. [Contribution of tropical upland forests to carbon storage in Colombia].

    Science.gov (United States)

    Yepes, Adriana; Herrera, Johana; Phillips, Juan; Galindo, Gustavo; Granados, Edwin; Duque, Alvaro; Barbosa, Adriana; Olarte, Claudia; Cardona, María

    2015-03-01

    The tropical montane forests in the Colombian Andean region are located above 1500 m, and have been heavily deforested. Despite the general presumption that productivity and hence carbon stocks in these ecosystems are low, studies in this regard are scarce. This study aimed to (i) to estimate Above Ground Biomass (AGB) in forests located in the South of the Colombian Andean region, (ii) to identify the carbon storage potential of tropical montane forests dominated by the black oak Colombobalanus excelsa and to identify the relationship between AGB and altitude, and (iii) to analyze the role of tropical mountain forests in conservation mechanisms such as Payment for Environmental Services (PES) and Reducing Emissions from Deforestation and Degradation (REDD+). Twenty six 0.25 ha plots were randomly distributed in the forests and all trees with D > or =10 cm were measured. The results provided important elements for understanding the role of tropical montane forests as carbon sinks. The information produced can be used in subnational initiatives, which seek to mitigate or reduce the effects of deforestation through management or conservation of these ecosystems, like REDD+ or PES. The AGB and carbon stocks results obtained were similar to those reported for lowland tropical forests. These could be explained by the dominance and abundance of C. excelsa, which accounted for over 81% of AGB/carbon. The error associated with the estimates of AGB/carbon was 10.58%. We found a negative and significant relationship between AGB and altitude, but the higher AGB values were in middle altitudes (approximatly = 700-1800 m), where the environmental conditions could be favorable to their growth. The carbon storage potential of these forests was higher. However, if the historical rate of the deforestation in the study area continues, the gross emissions of CO2e to the atmosphere could turn these forests in to an important emissions source. Nowadays, it is clear that tropical

  14. Temperature and rainfall strongly drive temporal growth variation in Asian tropical forest trees.

    Science.gov (United States)

    Vlam, Mart; Baker, Patrick J; Bunyavejchewin, Sarayudh; Zuidema, Pieter A

    2014-04-01

    Climate change effects on growth rates of tropical trees may lead to alterations in carbon cycling of carbon-rich tropical forests. However, climate sensitivity of broad-leaved lowland tropical trees is poorly understood. Dendrochronology (tree-ring analysis) provides a powerful tool to study the relationship between tropical tree growth and annual climate variability. We aimed to establish climate-growth relationships for five annual-ring forming tree species, using ring-width data from 459 canopy and understory trees from a seasonal tropical forest in western Thailand. Based on 183/459 trees, chronologies with total lengths between 29 and 62 years were produced for four out of five species. Bootstrapped correlation analysis revealed that climate-growth responses were similar among these four species. Growth was significantly negatively correlated with current-year maximum and minimum temperatures, and positively correlated with dry-season precipitation levels. Negative correlations between growth and temperature may be attributed to a positive relationship between temperature and autotrophic respiration rates. The positive relationship between growth and dry-season precipitation levels likely reflects the strong water demand during leaf flush. Mixed-effect models yielded results that were consistent across species: a negative effect of current wet-season maximum temperatures on growth, but also additive positive effects of, for example, prior dry-season maximum temperatures. Our analyses showed that annual growth variability in tropical trees is determined by a combination of both temperature and precipitation variability. With rising temperature, the predominantly negative relationship between temperature and growth may imply decreasing growth rates of tropical trees as a result of global warming.

  15. Nupela species (Naviculales: Bacillariophyceae from Colombian lowland waters including N. acaciensis nov. sp. and N. catatumbensis nov. sp.

    Directory of Open Access Journals (Sweden)

    Silvia Sala

    2014-03-01

    Full Text Available The genus Nupela comprises ca. 50 species that generally have a distribution restricted by bioclimatic frontiers. As part of an integrated analysis of the diatom flora of Colombia, in this study we focused our interest on the genus Nupela from lowland waters. Periphyton samples were collected from 150 sites of lotic water bodies in Colombia, taking into account hidrogeomorfological variability. In each sampling station, periphyton samples were obtained by scraping, and temperature, pH, dissolved oxygen and conductivity variables were measured. Samples were processed by both light microscopy (LM; Carl Zeiss Axio Scope.A1 and scanning electron microscopy (SEM; FEI-Quanta 450 and a Jeol JSM-6360 LV. The genus Nupela was found in 28 sites. Five taxa were identified, described and illustrated from tropical or subtropical environments: N. lesothensis, N. praecipua y N. subpallavicinii; these were new records for Colombia, and N. acaciensis and N. catatumbensis two new species for science. N. acaciensis is characterized by raphe branches of both valves equally long combined with cymbelloid symmetry, striae built by 2 transapically elongated areolae that delimit a longitudinal line at each hemivalve. N. catatumbensis is characterized by the presence of a well developed raphe in both valves; valves lanceolate with subcapitated to capitated ends and cymbelloid symmetry, striae built by 3-4 transapically elongated areolae, interestriae elevated as transapical ribs and internal proximal raphe ends hook-shaped. The genus Nupela was widely distributed in the studied basins but showed different distribution patterns: N. acaciensis and N. subpallavicini had a restricted distribution, while N. catatumbensis, N. lesothensis and N. praecipua had a wider distribution, and were collected in sites with significant variations in their ecomorphology, altitude, temperature, pH and electrolyte content.

  16. Water Level Fluctuations in the Congo Basin Derived from ENVISAT Satellite Altimetry

    Directory of Open Access Journals (Sweden)

    Mélanie Becker

    2014-09-01

    Full Text Available In the Congo Basin, the elevated vulnerability of food security and the water supply implies that sustainable development strategies must incorporate the effects of climate change on hydrological regimes. However, the lack of observational hydro-climatic data over the past decades strongly limits the number of studies investigating the effects of climate change in the Congo Basin. We present the largest altimetry-based dataset of water levels ever constituted over the entire Congo Basin. This dataset of water levels illuminates the hydrological regimes of various tributaries of the Congo River. A total of 140 water level time series are extracted using ENVISAT altimetry over the period of 2003 to 2009. To improve the understanding of the physical phenomena dominating the region, we perform a K-means cluster analysis of the altimeter-derived river level height variations to identify groups of hydrologically similar catchments. This analysis reveals nine distinct hydrological regions. The proposed regionalization scheme is validated and therefore considered reliable for estimating monthly water level variations in the Congo Basin. This result confirms the potential of satellite altimetry in monitoring spatio-temporal water level variations as a promising and unprecedented means for improved representation of the hydrologic characteristics in large ungauged river basins.

  17. Investigation on the rapid degradation of congo red catalyzed by activated carbon powder under microwave irradiation

    International Nuclear Information System (INIS)

    Zhang Zhaohong; Shan Yabo; Wang Jun; Ling Hongjie; Zang Shuliang; Gao Wei; Zhao Zhe; Zhang Huachun

    2007-01-01

    Azo dyestuff-congo red in aqueous solution can be degraded rapidly under microwave irradiation in the presence of activated carbon powder. The results showed that the degradation ratio could reach 87.79% for 25 mL total volume with 50 mg/L congo red and 2.0 g/L activated carbon powder under 1.5 min microwave irradiation. Furthermore, within the same irradiation time, congo red could be degraded fully by increasing addition amount (e.g. 3.6 g/L) of activated carbon powder and the degradation ratio was up to 96.49%. Otherwise, with the same addition amount, congo red also could be degraded completely by prolonging irradiation time (e.g. 2.5 min) and the degradation ratio was up to 97.88%. In addition, the influences of microwave irradiation time, initial concentration of congo red, addition amount and used times of activated carbon powder as well as solution acidity on the degradation were discussed in details adopting UV-vis spectra, FT-IR spectra, ion chromatography, high phase liquid chromatography (HPLC) and TOC analysis technologies. Here, the method using activated carbon powder as catalyst under microwave irradiation shows many advantages including high degradation ratios, short reaction time, low costs, no intermediates and no secondary pollution. Therefore, it may be fit for dealing with various azo dyestuff wastewaters on a large scale

  18. The state of emergency care in Democratic Republic of Congo

    Directory of Open Access Journals (Sweden)

    Luc Malemo Kalisya

    2015-12-01

    Full Text Available The Democratic Republic of Congo (DRC is the second largest country on the African continent with a population of over 70 million. It is also a major crossroad through Africa as it borders nine countries. Unfortunately, the DRC has experienced recurrent political and social instability throughout its history and active fighting is still prevalent today. At least two decades of conflict have devastated the civilian population and collapsed healthcare infrastructure. Life expectancy is low and government expenditure on health per capita remains one of the lowest in the world. Emergency Medicine has not been established as a specialty in the DRC. While the vast majority of hospitals have emergency rooms or salle des urgences, this designation has no agreed upon format and is rarely staffed by doctors or nurses trained in emergency care. Presenting complaints include general and obstetric surgical emergencies as well as respiratory and diarrhoeal illnesses. Most patients present late, in advanced stages of disease or with extreme morbidity, so mortality is high. Epidemics include HIV, cholera, measles, meningitis and other diarrhoeal and respiratory illnesses. Lack of training, lack of equipment and fee-for-service are cited as barriers to care. Pre-hospital care is also not an established specialty. New initiatives to improve emergency care include training Congolese physicians in emergency medicine residencies and medic ranger training within national parks.

  19. Crimean-Congo Hemorrhagic Fever: Tick-Host-Virus Interactions

    Directory of Open Access Journals (Sweden)

    Anna Papa

    2017-05-01

    Full Text Available Crimean-Congo hemorrhagic fever virus (CCHFV is transmitted to humans by bite of infected ticks or by direct contact with blood or tissues of viremic patients or animals. It causes to humans a severe disease with fatality up to 30%. The current knowledge about the vector-host-CCHFV interactions is very limited due to the high-level containment required for CCHFV studies. Among ticks, Hyalomma spp. are considered the most competent virus vectors. CCHFV evades the tick immune response, and following its replication in the lining of the tick's midgut, it is disseminated by the hemolymph in the salivary glands and reproductive organs. The introduction of salivary gland secretions into the host cells is the major route via which CCHFV enters the host. Following an initial amplification at the site of inoculation, the virus is spread to the target organs. Apoptosis is induced via both intrinsic and extrinsic pathways. Genetic factors and immune status of the host may affect the release of cytokines which play a major role in disease progression and outcome. It is expected that the use of new technology of metabolomics, transcriptomics and proteomics will lead to improved understanding of CCHFV-host interactions and identify potential targets for blocking the CCHFV transmission.

  20. Brucellosis in Patients with Crimean-Congo Hemorrhagic Fever

    Directory of Open Access Journals (Sweden)

    Fazilet Duygu

    2017-12-01

    Full Text Available Background: Crimean-Congo hemorrhagic fever (CCHF is a fatal zoonotic viral disease caused by infection with a tick-borne virus of the genus Nairovirus. In this study, we investigated the incidence of brucellosis in patients diag­nosed with CCHF.Methods: Overall, 169 patients hospitalized with an initial diagnosis of CCHF were included in 2011 in To­kat/ Turkey. Immunoglobulin M (IgM antibodies and/or PCR results were used in the laboratory diagnosis of CCHF, while plate and standard tube agglutination (STA tests were used to diagnose brucellosis.Results: Overall, 120 patients (79% with positive PCR tests were diagnosed with CCHF. Five (4.16% were also diag­nosed with brucellosis based on the positive plate and STA test results. Four patients (2.36% had negative CCHF PCR and positive STA test results.Conclusion: Brucellosis and CCHF can mimic each other and that all patients with CCHF or brucellosis should be screened for both conditions.

  1. [Hypertensive emergencies at the University Hospital Center in Brazzaville, Congo].

    Science.gov (United States)

    Ellenga, Mbolla B F; Gombet, T R; Mahoungou, Guimbi K C; Otiobanda, G F; Ossou, Nguiet P M; Ikama, M S; Kimbally-Kaky, G; Etitiele, F

    2011-02-01

    The purpose of this retrospective study conducted in the emergency department of the University Hospital Center in Brazzaville, Congo was to determine the prevalence and clinical characteristics of hypertensive emergencies. With a total of 76 patients admitted during the study period, the prevalence of hypertensive emergency was 4%. The sex ratio was 1 and mean patient age was 57.3 years (range, 30 to 80 years). Risk factors included obesity in 62 cases (81.6%), history of hypertension in 65 (85.5%) and low socioeconomic level in 58 (76.3%). Mean delay for consultation was 50 hours (range, 1 to 240 hours). The disease underlying the hypertensive emergency was stroke with 38 cases (50%), heart failure in 20 (26.3%), hypertensive encephalopathy in 11 (14.4%), malignant hypertension in 9 (11.8%), and renal failure in 10 (13.1%). The mean length of emergency treatment was 14.7 hours (range, 5 to 48 hours). Eight deaths (10.5%) occurred during hospitalization in the emergency department.

  2. Hepatitis in Patients with Crimean –Congo Hemorrhagic Fever

    Directory of Open Access Journals (Sweden)

    Batool Sharifi-Mood

    2014-04-01

    Full Text Available Background: Crimean–Congo hemorrhagic fever (CCHF is a viral disease and causing approximately 30% fatality rate. Recent studies have been reported that hepatitis in CCHF patients is with high mortality. The aim of this study was to determine the prevalence of hepatitis in the CCHF cases and also detect the mortality rate among patients with hepatitis. Materials and Methods: The present study was conducted in patients with CCHF who were hospitalized in Boo-Ali hospital in Zahedan between Oct 2009 to Feb 2012. Liver function tests including aminotransferase enzymes and prothrombin time and mortality rate were evaluated. Results: Among 53 patients with CCHF, hepatitis was seen in 19 patients (45%. Nine patients died (21%. All dead patients had a serum aminotransaminase level ≥10 times the upper normal limit. Conclusion: Our study showed that hepatitis is prevalent in CCHF patients and a serum aminotransaminase level ≥5 times the upper normal limit (UNL is a risk factor for severe disease and high mortality.

  3. Diet and kwashiorkor: a prospective study from rural DR Congo

    Directory of Open Access Journals (Sweden)

    Hallgeir Kismul

    2014-04-01

    Full Text Available The etiology of kwashiorkor remains enigmatic and longitudinal studies examining potential causes of kwashiorkor are scarce. Using historical, longitudinal study data from the rural area of Bwamanda, Democratic Republic of Congo, we investigated the potential causal association between diet and the development of kwashiorkor in 5 657 preschool children followed 3-monthly during 15 months. We compared dietary risk factors for kwashiorkor with those of marasmus. Kwashiorkor was diagnosed as pitting oedema of the ankles; marasmus as abnormal visibility of skeletal structures and palpable wasting of the gluteus muscle. A 24-h recall was administered 3-monthly to record the consumption of the 41 locally most frequent food items. We specified Hanley–Miettinen smooth-in-time risk models containing potential causal factors, including food items, special meals prepared for the child, breastfeeding, disease status, nutritional status, birth rank, age, season and number of meals. Bayesian Information Criteria identified the most plausible causal model of why some children developed kwashiorkor. In a descriptive analysis of the diet at the last dietary assessment prior to development of kwashiorkor, the diet of children who developed kwashiorkor was characterized by low consumption of sweet potatoes, papaya and “other vegetables” [0.0% , 2.3% (95% CI [0.4, 12.1] and 2.3% (95% CI [0.4, 12.1

  4. Tropical varieties, maps and gossip

    NARCIS (Netherlands)

    Frenk, B.J.

    2013-01-01

    Tropical geometry is a relatively new field of mathematics that studies the tropicalization map: a map that assigns a certain type of polyhedral complex, called a tropical variety, to an embedded algebraic variety. In a sense, it translates algebraic geometric statements into combinatorial ones. An

  5. The Ritual "Play of the Congos" of North-Central Panama: Its Sociolinguistic Implications. Sociolinguistic Working Paper Number 85.

    Science.gov (United States)

    Joly, Luz Graciela

    An excerpt from the "Play of the Congos," given in Congo, Spanish, and English, exemplifies the sociolinguistic features of the combined play and ritual language used by the Afro-Hispanic population in the Caribbean region of the Costa Abajo in north-central Panama. The sociolinguistic norms are an important part of the "regulation…

  6. Four new species of deep water agglutinated foraminifera from the Oligocene-Miocene of the Congo Fan (offshore Angola)

    OpenAIRE

    Kender, S.; Kaminski, M. A.; Jones, R. W.

    2006-01-01

    Four new species of deep-water agglutinated benthic foraminifera are described from the Oligocene and Miocene of the Congo Fan, offshore Angola. Scherochorella congoensis n.sp., Paratrochamminoides goroyskiformis n.sp., Haplophragmoides nauticus n.sp. and Portatrochammina profunda n.sp. all occur in deep-sea turbiditic shales and sands from the distal section of the Congo Fan.

  7. Tropical Cyclone Report, 1988

    Science.gov (United States)

    1988-01-01

    Cmdr. David Gray; National Weather Service 5. Cooperation with the Naval Environmental Pacific Region for the startup of 24-hour operatiois at Ponape...0.1 27.7 TOTAL CASES 3 1 1 4 12 27 54 56 30 25 7 1 221 * (GRAY, 1979) TABLE 4-3 ANNUAL VARIATION C SOTR MUSHER TROPICAL CYCLOUZ BY O(EN BASIN SOUTH

  8. Utilization of tropical rabbits

    African Journals Online (AJOL)

    5,0' a,b"differ (P<0,05) for reproducing rabbits, and may aid the prevention of enteric diseases. In Trial 3, ADG of several tropical legumes was the same as that obtained with alfalfa (Table 3). Gains with guinea grass, cassava, stylosanthes and the winged bean were lower than with alfalfa. Digestibilityof the protein and fibre ...

  9. [Tropical sprue (author's transl)].

    Science.gov (United States)

    Gras, C; Chapoy, P; Aubry, P

    1981-01-01

    Tropical sprue is a disease of the small intestine characterized by a malabsorption syndrome with a subtotal or partial mucosal atrophy. It is observed in Asia and Central America. It appears to be rare in Africa but its real frequency is unknown as small bowel biopsys are not routinely done. Bacterial overgrowth as well as giardiasis may be trigger factors of the disease the pathogenesis of which is still incompletely understood. The disease beginning as chronic diarrhea is later on characterized by an aphtoïd stomatitis and a macrocytic anemia. Treatment with antibiotics and folic acid is efficient and has a diagnostic value. If treatment is started lately, vitamin B 12 is then also necessary. In any intestinal syndrome observed in tropical areas without an ascertained etiologic diagnosis, peroral biopsie of the small intestine is requested. However, with the use of pediatric endoscope it will be possible to appreciate the respective incidence of tropical sprue and asymptomatic tropical sprue in Africa South of the Sahara.

  10. Securing tropical forest carbon

    DEFF Research Database (Denmark)

    Scharlemann, Jörn P. W.; Kapos, Valerie; Campbell, Alison

    2010-01-01

    Forest loss and degradation in the tropics contribute 6-17% of all greenhouse gas emissions. Protected areas cover 217.2 million ha (19.6%) of the world's humid tropical forests and contain c. 70.3 petagrams of carbon (Pg C) in biomass and soil to 1 m depth. Between 2000 and 2005, we estimate...... that 1.75 million ha of forest were lost from protected areas in humid tropical forests, causing the emission of 0.25-0.33 Pg C. Protected areas lost about half as much carbon as the same area of unprotected forest. We estimate that the reduction of these carbon emissions from ongoing deforestation...... in protected sites in humid tropical forests could be valued at USD 6,200-7,400 million depending on the land use after clearance. This is >1.5 times the estimated spending on protected area management in these regions. Improving management of protected areas to retain forest cover better may be an important...

  11. Tropic Testing of Vehicles

    Science.gov (United States)

    2014-08-27

    kilometer track running through tropical forest. The track is a combination of a bauxite /dirt base with grades on the road up to 20 percent and log...bridges crossing 11 creeks. The track site is located in a private concession used mainly for gold mining ; however, logging operations are active in the

  12. Diversity of lowland hay meadows and pastures in Western and Central Europe

    NARCIS (Netherlands)

    Rodríguez-Rojo, Maria Pilar; Jiménez-Alfaro, Borja; Jandt, Ute; Bruelheide, Helge; Rodwell, John S.; Schaminée, Joop H.J.; Perrin, Philip M.; Kacki, Zygmunt; Willner, Wolfgang; Fernández-González, Federico; Chytrý, Milan

    2017-01-01

    Questions: Which are the main vegetation types of lowland hay meadows and pastures in Western and Central Europe? What are the main environmental gradients that drive patterns of species composition? Is it possible to classify these grasslands to phytosociological alliances that reflect management

  13. Sweet potato weevil (Cylas formicarius) incidence in the humid lowlands of Papua New Guinea

    NARCIS (Netherlands)

    Powell, K.S.; Hartemink, A.E.; Eganae, J.F.; Walo, C.; Poloma, S.

    2001-01-01

    Sweet potato is the main staple crop in PNG and this paper presents a study from the humid lowlands of the Morobe Province. Three experiments were carried out at two locations (Hobu and Unitech) to evaluate the effect of inorganic fertiliser inputs and fallow vegetation on the incidence of sweet

  14. Alien roadside species more easily invade alpine than lowland plant communities in a subarctic mountain ecosystem.

    Directory of Open Access Journals (Sweden)

    Jonas J Lembrechts

    Full Text Available Effects of roads on plant communities are not well known in cold-climate mountain ecosystems, where road building and development are expected to increase in future decades. Knowledge of the sensitivity of mountain plant communities to disturbance by roads is however important for future conservation purposes. We investigate the effects of roads on species richness and composition, including the plant strategies that are most affected, along three elevational gradients in a subarctic mountain ecosystem. We also examine whether mountain roads promote the introduction and invasion of alien plant species from the lowlands to the alpine zone. Observations of plant community composition were made together with abiotic, biotic and anthropogenic factors in 60 T-shaped transects. Alpine plant communities reacted differently to road disturbances than their lowland counterparts. On high elevations, the roadside species composition was more similar to that of the local natural communities. Less competitive and ruderal species were present at high compared with lower elevation roadsides. While the effects of roads thus seem to be mitigated in the alpine environment for plant species in general, mountain plant communities are more invasible than lowland communities. More precisely, relatively more alien species present in the roadside were found to invade into the surrounding natural community at high compared to low elevations. We conclude that effects of roads and introduction of alien species in lowlands cannot simply be extrapolated to the alpine and subarctic environment.

  15. Alien roadside species more easily invade alpine than lowland plant communities in a subarctic mountain ecosystem.

    Science.gov (United States)

    Lembrechts, Jonas J; Milbau, Ann; Nijs, Ivan

    2014-01-01

    Effects of roads on plant communities are not well known in cold-climate mountain ecosystems, where road building and development are expected to increase in future decades. Knowledge of the sensitivity of mountain plant communities to disturbance by roads is however important for future conservation purposes. We investigate the effects of roads on species richness and composition, including the plant strategies that are most affected, along three elevational gradients in a subarctic mountain ecosystem. We also examine whether mountain roads promote the introduction and invasion of alien plant species from the lowlands to the alpine zone. Observations of plant community composition were made together with abiotic, biotic and anthropogenic factors in 60 T-shaped transects. Alpine plant communities reacted differently to road disturbances than their lowland counterparts. On high elevations, the roadside species composition was more similar to that of the local natural communities. Less competitive and ruderal species were present at high compared with lower elevation roadsides. While the effects of roads thus seem to be mitigated in the alpine environment for plant species in general, mountain plant communities are more invasible than lowland communities. More precisely, relatively more alien species present in the roadside were found to invade into the surrounding natural community at high compared to low elevations. We conclude that effects of roads and introduction of alien species in lowlands cannot simply be extrapolated to the alpine and subarctic environment.

  16. Choosing soil management systems for rice production on lowland soils in South Brazil

    NARCIS (Netherlands)

    Lima, A.C.R.; Hoogmoed, W.B.

    2009-01-01

    Lowland soils are commonly found in the state of Rio Grande do Sul, Southern of Brazil, where they represent around 20% of the total area of the state. Deficient drainage is the most important natural characteristic of these soils which therefore are mainly in use for flood-irrigated rice (Oriza

  17. Description of the phosphorus sorption and desorption processes in lowland peaty clay soils

    NARCIS (Netherlands)

    Schoumans, O.F.

    2013-01-01

    To determine phosphorus (P) losses from agricultural land to surface water, information is needed about the behavior of P in soils. In this study, the sorption and desorption characteristics of lowland peaty clay soils are described based on experimental laboratory studies. The maximum P sorption

  18. Human-driven topographic effects on the distribution of forest in a flat, lowland agricultural region

    DEFF Research Database (Denmark)

    Odgaard, Mette Vestergaard; Moeslund, Jesper Erenskjold; Dalgaard, Tommy

    2014-01-01

    Complex topography buffers forests against deforestation in mountainous regions. However, it is unknown if terrain also shapes forest distribution in lowlands where human impacts are likely to be less constrained by terrain. In such regions, if important at all, topographic effects will depend...

  19. Streamflow, a GIS-based Environmental Assessment Tool for Lowland Streams

    NARCIS (Netherlands)

    Pieterse, N.M.; Olde Venterink, H.; Schot, P.P.; Verkroost, A.W.M.

    1998-01-01

    Human activities, such as stream management, drainage, urbanization and agriculture, heavily influence the aquatic ecosystems in small lowland streams. For the assessment of the impact of human activities of aquatic ecosystems, a modeling tool is created. This modeling tool is part of the EU-life

  20. Substrate homogenization affects survival and fitness in the lowland stream caddisflies Micropterna sequax and Potamophylax rotundipennis

    NARCIS (Netherlands)

    Westveer, Judith J.; Verdonschot, Piet F.M.; Verdonschot, Ralf C.M.

    2017-01-01

    Loss of substrate heterogeneity or patchiness is common in lowland streams with disturbed hydrological regimes. At the reach scale, peak discharges tend to homogenize the stream bed and decrease the availability of specific microhabitat types. This spatial shift in habitats toward a more

  1. Dry season diets of sympatric ungulates in lowland Nepal: competition and facilitation in alluvial tall grasslands

    NARCIS (Netherlands)

    Wegge, P.; Shrestha, A.K.; Moe, S.R.

    2006-01-01

    Based on microhistological analyses of faecal material, we compared the early dry season diets of greater one-horned rhinoceros Rhinoceros unicornis, swamp deer Cervus duvauceli and hog deer Axis porcinus, which inhabit the same alluvial grassland habitat complex in lowland Nepal. Their diets were

  2. Seasonal rainfall-runoff relationships in a lowland forested watershed in the southeastern USA

    Science.gov (United States)

    Ileana La Torre Torres; Devendra Amatya; Ge Sun; Timothy Callahan

    2011-01-01

    Hydrological processes of lowland watersheds of the southern USA are not well understood compared to a hilly landscape due to their unique topography, soil compositions, and climate. This study describes the seasonal relationships between rainfall patterns and runoff (sum of storm flow and base flow) using 13 years (1964–1976) of rainfall and stream flow data for a low...

  3. Morphodynamic regime change induced by riparian vegetation in a restored lowland stream

    NARCIS (Netherlands)

    Eekhout, J.P.C.; Hoitink, A.J.F.

    2013-01-01

    With the aim to establish and understand morphological changes in response to stream restoration measures, a detailed monitoring plan was implemented in a lowland stream called Lunterse Beek, located in the Netherlands. Over a period of 1.5 yr, the monitoring 5 included serial morphological surveys,

  4. Hydrology and substrates: determinants of oligochaete distribution in lowland streams (the Netherlands)

    NARCIS (Netherlands)

    Verdonschot, P.F.M.

    2001-01-01

    In most soft-bottomed, lowland streams in the Netherlands discharge regimes largely follow the precipitation pattern. Winter discharges are higher and much more dynamic then summer discharges, although rain storms throughout the year cause unexpected peak flows. Minimal precipitation, reduced stream

  5. Characterization of the gastrointestinal bacterial communities of western lowland gorillas (Gorilla gorilla gorilla)

    Czech Academy of Sciences Publication Activity Database

    Gomez, A.; Yeoman, C. J.; White, B. A.; Petrželková, Klára Judita; Todd, A.; Stumpf, R. M.; Nelson, K. E.; Torralba, M.; Gillis, M.; Wilson, B. A.; Leigh, S. R.

    2013-01-01

    Roč. 150, S56 (2013), s. 132-133 ISSN 0002-9483. [Annual Meeting of the American-Association of Physical Anthropologists /82./. 09.04.2013-13.04.2013, Knoxville] Institutional support: RVO:68081766 Keywords : bacteria * western lowland gorillas Subject RIV: EG - Zoology http://onlinelibrary.wiley.com/doi/10.1002/ajpa.22247/pdf

  6. Seasonality in the coastal lowlands of Kenya; Pt. 4/5 : Food consumption and anthropometry

    NARCIS (Netherlands)

    Foeken, D.W.J.; Klaver, W.; Niemeijer, R.

    1991-01-01

    This is Part 4/5 of a series concerned with seasonality in the coastal lowlands of Kenya. Household surveys were carried out in six locations in Kwale and Kilifi Districts in 1985-1987. The present report deals with food consumption and the nutritional condition of the study population. Results show

  7. Multiple stress response of lowland stream benthic macroinvertebrates is dependent on habitat type

    DEFF Research Database (Denmark)

    Graeber, Daniel; Jensen, Tinna M.; Rasmussen, Jes

    2017-01-01

    Worldwide, lowland stream ecosystems are exposed to multiple anthropogenic stress due to the combination of water scarcity, eutrophication and fine sedimentation. The understanding of the effects of such multiple stress on stream benthic macroinvertebrates has been growing in the recent years...

  8. Influence of Disturbance on Habitats and Biological Communities in Lowland Streams

    DEFF Research Database (Denmark)

    Pedersen, Morten Lauge; Friberg, N.

    2009-01-01

    ). The results indicate that disturbance cascades through the stream ecosystem, primarily meditated by changes in macrophyte communities that are essential providers of habitat in unshaded lowland streams in which other structural elements, as coarse inorganic substrates and woody debris, are scarce...

  9. Impact of stress on the gut microbiome of free-ranging western lowland gorillas

    Czech Academy of Sciences Publication Activity Database

    Vlčková, Klára; Shutt-Phillips, K. A.; Heistermann, M.; Pafčo, B.; Petrželková, Klára Judita; Todd, A.; Modrý, D.; Nelson, K. E.; Wilson, B. A.; Stumpf, R. M.; White, B. A.; Leigh, S. R.; Gomez, A.

    2018-01-01

    Roč. 164, č. 1 (2018), s. 40-44 ISSN 1350-0872 Institutional support: RVO:68081766 Keywords : gastrointestinal-tract * disease * habituation * clostridium * disrupts * health * organ * flora * gastrointestinal microbiome * bacteria * stress * western lowland gorilla * faecal glucocorticoid metabolites Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 2.151, year: 2016

  10. The Impact of Climate Change on Metal Transport in a Lowland Catchment

    NARCIS (Netherlands)

    Wijngaard, René R.; van der Perk, Marcel|info:eu-repo/dai/nl/074715437; van der Grift, Bas|info:eu-repo/dai/nl/373433484; de Nijs, Ton C M; Bierkens, Marc F P|info:eu-repo/dai/nl/125022794

    2017-01-01

    This study investigates the impact of future climate change on heavy metal (i.e., Cd and Zn) transport from soils to surface waters in a contaminated lowland catchment. The WALRUS hydrological model is employed in a semi-distributed manner to simulate current and future hydrological fluxes in the

  11. Approaches to restoration of oak forests on farmed lowlands of the Mississippi River and its tributaries

    Science.gov (United States)

    Emile S. Gardiner; Daniel C. Dey; John A. Stanturf; Brian Roy. Lockhart

    2010-01-01

    The lowlands associated with the Mississippi River and its tributaries historically supported extensive broadleaf forests that were particularly rich in oak (Quercus spp.) species. Beginning in the 1700s, deforestation for agriculture substantially reduced the extent of the original forest, and fragmented the remainder into small parcels. More...

  12. Ecology of malaria infections in western lowland gorillas inhabiting Dzanga Sangha Protected Areas, Central African Republic

    Czech Academy of Sciences Publication Activity Database

    Mapua, M. I.; Qablan, M. A.; Pomajbíková, K.; Petrželková, Klára Judita; Hůzová, Z.; Rádrová, J.; Votýpka, J.; Todd, A.; Jirků, M.; Leendertz, F. H.; Lukeš, J.; Neel, C.; Modrý, D.

    2015-01-01

    Roč. 142, č. 7 (2015), s. 890-900 ISSN 0031-1820 Institutional support: RVO:68081766 Keywords : Plasmodium spp. * African great apes * malaria * lowland gorilla Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 3.031, year: 2015

  13. Ecosystem and restoration consequences of invasive woody species removal in Hawaiian lowland wet forest

    Science.gov (United States)

    R. Ostertag; S. Cordell; J. Michaud; T.C. Cole; J.R. Schulten; K.M. Publico; J.H. Enoka

    2009-01-01

    A removal experiment was used to examine the restoration potential of a lowland wet forest in Hawaii, a remnant forest type that has been heavily invaded by non-native species and in which there is very little native species regeneration. All non-native woody and herbaceous biomass (approximately 45% of basal area) was removed in four 100-m² removal plots;...

  14. Organic matter sources, fluxes and greenhouse gas exchange in the Oubangui River (Congo River basin

    Directory of Open Access Journals (Sweden)

    S. Bouillon

    2012-06-01

    Full Text Available The Oubangui is a major tributary of the Congo River, draining an area of ~500 000 km2 mainly consisting of wooded savannahs. Here, we report results of a one year long, 2-weekly sampling campaign in Bangui (Central African Republic since March 2010 for a suite of physico-chemical and biogeochemical characteristics, including total suspended matter (TSM, bulk concentration and stable isotope composition of particulate organic carbon (POC and δ13CPOC, particulate nitrogen (PN and δ15NPN, dissolved organic carbon (DOC and δ13CDOC, dissolved inorganic carbon (DIC and δ13CDIC, dissolved greenhouse gases (CO2, CH4 and N2O, and dissolved lignin composition. δ13C signatures of both POC and DOC showed strong seasonal variations (−30.6 to −25.8‰, and −31.8 to −27.1‰, respectively, but their different timing indicates that the origins of POC and DOC may vary strongly over the hydrograph and are largely uncoupled, differing up to 6‰ in δ13C signatures. Dissolved lignin characteristics (carbon-normalised yields, cinnamyl:vanillyl phenol ratios, and vanillic acid to vanillin ratios showed marked differences between high and low discharge conditions, consistent with major seasonal variations in the sources of dissolved organic matter. We observed a strong seasonality in pCO2, ranging between 470 ± 203 ppm for Q < 1000 m3 s−1 (n=10 to a maximum of 3750 ppm during the first stage of the rising discharge. The low POC/PN ratios, high %POC and low and variable δ13CPOC signatures during low flow conditions suggest that the majority of the POC pool during this period consists of in situ produced phytoplankton, consistent with concurrent pCO2 (partial pressure of CO2 values only slightly

  15. Tropical myeloneuropathies: the hidden endemias.

    Science.gov (United States)

    Román, G C; Spencer, P S; Schoenberg, B S

    1985-08-01

    Tropical myeloneuropathies include tropical ataxic neuropathy and tropical spastic paraparesis. These disorders occur in geographic isolates in several developing countries and are associated with malnutrition, cyanide intoxication from cassava consumption, tropical malabsorption (TM), vegetarian diets, and lathyrism. TM-malnutrition was a probable cause of myeloneuropathies among Far East prisoners of war in World War II. Clusters of unknown etiology occur in India, Africa, the Seychelles, several Caribbean islands, Jamaica, and Colombia. Treponemal infection (yaws) could be an etiologic factor in the last two. Tropical myeloneuropathies, a serious health problem, are multifactorial conditions that provide unsurpassed opportunities for international cooperation and neurologic research.

  16. Optical properties of amyloid stained by Congo red: history and mechanisms.

    Science.gov (United States)

    Howie, Alexander J; Brewer, Douglas B

    2009-04-01

    Amyloid stained by Congo red has striking optical properties that generally have been poorly described and inadequately explained, although they can be understood from principles of physical optics. Molecules of Congo red are orientated on amyloid fibrils, and so the dye becomes dichroic and birefringent. The birefringence varies with wavelength in accordance with a fundamental property of all light-transmitting materials called anomalous dispersion of the refractive index around an absorption peak. The combination of this and absorption of light, with modification by any additional birefringence in the optical system, explains the various colours that can be seen in Congo red-stained amyloid between crossed polariser and analyser, and also when the polariser and analyser are progressively uncrossed. These are called anomalous colours.

  17. Can lowland dry forests represent a refuge from avian malaria for native Hawaiian birds?

    Science.gov (United States)

    Tucker-Mohl, Katherine; Hart, Patrick; Atkinson, Carter T.

    2010-01-01

    Hawaii's native birds have become increasingly threatened over the past century. Introduced mosquito borne diseases such as avian malaria may be responsible for the near absence of endemic Hawaiian forest birds in low-elevation habitats. The recent recognition that some native Hawaiian forest birds may be repopulating moist lowland habitats as a result of evolved resistance to this disease has increased the conservation value of these areas. Here, we investigate whether remnant low elevation dry forests on Hawaii Island provide natural 'refuges' from mosquito-transmitted malaria by nature of their low rainfall and absence of suitable natural sources of water for mosquito breeding. Unlike lowland wet forests where high rates of disease transmission may be selecting for disease resistance, lowland dry forests may provide some refuge for native forest birds without natural resistance to malaria. We mistnetted forest birds in two lowland dry forests and tested all native birds by microscopy and serology for avian malaria caused by the Plasmodium relictum parasite. We also conducted surveys for standing water and mosquito larvae. Overall prevalence of infections with Plasmodium relictum in the Hawaii Amakihi Hemignathus virens virens was 15%. Most infected birds had lowlevel parasitemias, suggesting chronic infections. Although avian malaria is present in these lowland dry forest Amakihi populations, infection rates are significantly lower than in wet forest populations at similar elevations. Sources of breeding mosquitoes in these forests appeared to be largely anthropogenic; thus, there is potential to manage dry forests as mosquito-free habitat for Hawaii Amakihi and other Hawaiian forest birds.

  18. Controls on anastomosis in lowland river systems: Towards process-based solutions to habitat conservation.

    Science.gov (United States)

    Marcinkowski, Paweł; Grabowski, Robert C; Okruszko, Tomasz

    2017-12-31

    Anastomosing rivers were historically common around the world before extensive agricultural and industrial development in river valleys. Few lowland anastomosing rivers remain in temperate zones, and the protection of these river-floodplain systems is an international conservation priority. However, the mechanisms that drive the creation and maintenance of multiple channels, i.e. anabranches, are not well understood, particularly for lowland rivers, making it challenging to identify effective management strategies. This study uses a novel multi-scale, process-based hydro-geomorphological approach to investigate the natural and anthropogenic controls on anastomosis in lowland river reaches. Using a wide range of data (hydrologic, cartographic, remote-sensing, historical), the study (i) quantifies changes in the planform of the River Narew, Poland over the last 100years, (ii) documents changes in the natural and anthropogenic factors that could be driving the geomorphic change, and (iii) develops a conceptual model of the controls of anastomosis. The results show that 110km of anabranches have been lost from the Narew National Park (6810ha), a 42% reduction in total anabranch length since 1900. The rates of anabranch loss have increased as the number of pressures inhibiting anabranch creation and maintenance has multiplied. The cessation of localized water level and channel management (fishing dams, water mills and timber rafting), the loss of traditional floodplain activities (seasonal mowing) and infrastructure construction (embanked roads and an upstream dam) are contributing to low water levels and flows, the deposition of sediment at anabranch inlets, the encroachment of common reed (Phragmites australis), and the eventual loss of anabranches. By identifying the processes driving the loss of anabranches, this study provides transferable insights into the controls of anastomosis in lowland rivers and the management solutions needed to preserve the unique

  19. A comparison of two common flight interception traps to survey tropical arthropods

    Directory of Open Access Journals (Sweden)

    Greg Lamarre

    2012-08-01

    Full Text Available Tropical forests are predicted to harbor most of the insect diversity on earth, but few studies have been conducted to characterize insect communities in tropical forests. One major limitation is the lack of consensus on methods for insect collection. Deciding which insect trap to use is an important consideration for ecologists and entomologists, yet to date few study has presented a quantitative comparison of the results generated by standardized methods in tropical insect communities. Here, we investigate the relative performance of two flight interception traps, the windowpane trap, and the more widely used malaise trap, across a broad gradient of lowland forest types in French Guiana. The windowpane trap consistently collected significantly more Coleoptera and Blattaria than the malaise trap, which proved most effective for Diptera, Hymenoptera, and Hemiptera. Orthoptera and Lepidoptera were not well represented using either trap, suggesting the need for additional methods such as bait traps and light traps. Our results of contrasting trap performance among insect orders underscore the need for complementary trapping strategies using multiple methods for community surveys in tropical forests.

  20. Yeasts dominate soil fungal communities in three lowland Neotropical rainforests.

    Science.gov (United States)

    Dunthorn, Micah; Kauserud, Håvard; Bass, David; Mayor, Jordan; Mahé, Frédéric

    2017-10-01

    Forest soils typically harbour a vast diversity of fungi, but are usually dominated by filamentous (hyphae-forming) taxa. Compared to temperate and boreal forests, though, we have limited knowledge about the fungal diversity in tropical rainforest soils. Here we show, by environmental metabarcoding of soil samples collected in three Neotropical rainforests, that Yeasts dominate the fungal communities in terms of the number of sequencing reads and OTUs. These unicellular forms are commonly found in aquatic environments, and their hyperdiversity may be the result of frequent inundation combined with numerous aquatic microenvironments in these rainforests. Other fungi that are frequent in aquatic environments, such as the abundant Chytridiomycotina, were also detected. While there was low similarity in OTU composition within and between the three rainforests, the fungal communities in Central America were more similar to each other than the communities in South America, reflecting a general biogeographic pattern also seen in animals, plants and protists. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  1. Anatomie de la Corruption en République Démocratique du Congo

    OpenAIRE

    Kodila Tedika, Oasis

    2013-01-01

    This article analysis a nature of corruption in Democratic Republic of Congo. It shows, with arguments, on the one hand the deserved reputation for a highly corrupt country, that one reads regularly in different collations on corruption and says to the complexity and depth of the corruption. The basis of the systemic side of corruption in this country. Cet article a pour objectif de décortiquer la nature de la corruption en République démocratique du Congo. Il démontre, avec arguments, d’une ...

  2. Effective Removal of Congo Red by Triarrhena Biochar Loading with TiO2 Nanoparticles

    Directory of Open Access Journals (Sweden)

    Peng Yu

    2018-01-01

    Full Text Available A composite of pyrolytic Triarrhena biochar loading with TiO2 nanoparticles has been synthesized by the sol-gel method. The composite shows a well-developed hollow mesoporous and macropore structure as characterized by XRD, BET, and SEM. When used as an absorbent to remove Congo red from aqueous solution, it was found that as-prepared composite performed better absorption capacity than single biochar or TiO2. The results suggest that biochar loading with TiO2 could be promisingly implemented as an environmentally friendly and inexpensive adsorbent for Congo red removal from wastewater.

  3. The transparency, reliability and utility of tropical rainforest land-use and land-cover change models.

    Science.gov (United States)

    Rosa, Isabel M D; Ahmed, Sadia E; Ewers, Robert M

    2014-06-01

    Land-use and land-cover (LULC) change is one of the largest drivers of biodiversity loss and carbon emissions globally. We use the tropical rainforests of the Amazon, the Congo basin and South-East Asia as a case study to investigate spatial predictive models of LULC change. Current predictions differ in their modelling approaches, are highly variable and often poorly validated. We carried out a quantitative review of 48 modelling methodologies, considering model spatio-temporal scales, inputs, calibration and validation methods. In addition, we requested model outputs from each of the models reviewed and carried out a quantitative assessment of model performance for tropical LULC predictions in the Brazilian Amazon. We highlight existing shortfalls in the discipline and uncover three key points that need addressing to improve the transparency, reliability and utility of tropical LULC change models: (1) a lack of openness with regard to describing and making available the model inputs and model code; (2) the difficulties of conducting appropriate model validations; and (3) the difficulty that users of tropical LULC models face in obtaining the model predictions to help inform their own analyses and policy decisions. We further draw comparisons between tropical LULC change models in the tropics and the modelling approaches and paradigms in other disciplines, and suggest that recent changes in the climate change and species distribution modelling communities may provide a pathway that tropical LULC change modellers may emulate to further improve the discipline. Climate change models have exerted considerable influence over public perceptions of climate change and now impact policy decisions at all political levels. We suggest that tropical LULC change models have an equally high potential to influence public opinion and impact the development of land-use policies based on plausible future scenarios, but, to do that reliably may require further improvements in the

  4. A crimean - congo hemorrhagic fever outbreak in northern balochistan

    International Nuclear Information System (INIS)

    Nadeem, M.; Ali, N.

    2007-01-01

    To describe the clinical characteristics, epidemiology, predictors of fatal outcome (PFO), and management effects of Crimean-Congo haemorrhagic fever (CCHF) patients during an outbreak in Northern Balochistan. Patients presenting with a fever of less than 2 weeks duration and bleeding manifestations were included. Clinical history was recorded and patients were placed on oral ribavirin, and hematological support. Diagnosis was established by PCR for CCHF or detection of CCHF specific IgM and IgG. Eighty-four patients were received, 34 (40.5%) were suspected of suffering from classical CCHF. All 34 (100%) patients presented with a history of fever and bleeding (epistaxis, gum bleeding, melena or haematuria). Mean platelet count was 30 x 109/L and mean ALT (alanine transferase) was 288 U/L. Among fatal cases, the mean platelet count was 18.4 x 10 9/L and ALT was 781 units/L. PCR for CCHF viral RNA performed on 10 patients was positive in 3 (30%) patients. CCHF specific IgM and IgG was positive in 17.6% (6/34). Four patients were brought in moribund condition and expired before treatment could be started, 4 patients expired during treatment and 76.5% (26/34) were cured. The overall mortality was 23.5% (8/34). Main predictors of fatal outcome were ALT z 150 units/L, activated partial thromboplastin time(aPT) z 60 seconds, prothrombin time (PT) z 34 seconds, aspartate transferase (AST) z 200 units/L, platelets o 20 x 109/L, and fibrinogen o 110 mg/dL. In this series of CCHF occurring in Northern parts of Balochistan, gastrointestinal tract bleeding was the worst prognostic factor associated with fatal outcome. Providing education to healthcare workers and at risk populations, hematological support, antiviral drugs, and barrier nursing may help reduce mortality. (author)

  5. Vectors of Crimean Congo Hemorrhagic Fever Virus in Iran

    Directory of Open Access Journals (Sweden)

    Zakkyeh Telmadarraiy

    2015-10-01

    Full Text Available Background: Ticks are important vectors and reservoirs of Crimean Congo Hemorrhagic Fever (CCHF virus. Human beings may be infected whenever the normal life cycle of the infected ticks on non- human vertebrate hosts is interrupted by the undesirable presence of humans in the cycle. A total of 26 species of Argasid and Ixodid ticks have been recorded in Iran; including nine Hyalomma, two Rhipicephalus, two Dermacentor, five Haemaphysalis, two Boophilus, one Ixodes and two Argas as well as three Ornithodoros species as blood sucking ectoparasites of livestock and poultries. The present paper reviews tick vectors of CCHF virus in Iran, focusing on the role of ticks in different provinces of Iran using reverse transcription polymerase chain reaction (RT-PCR assay.Methods: During ten years study, 1054 tick specimens; including two species of Argasidae and 17 species of Ixodidae were examined for their infection to CCHF virus genome. The output of all studies as well as related publications were discussed in the current paper.Results: The results show that Rhipicephalus sanguineus, Hyalomma marginatum, H. anatolicum, H. asiaticum and H. dromedarii were known as the most frequent species which were positive for CCHF virus.Conclusion: The status of ticks which were positive for CCHF virus revealed that unlike the most common idea that Hyalomma species are the most important vectors of CCHF virus, other ticks including Rhipicephalus,Haemaphysalis and Dermacentor can be reservoir of this virus; thus, considering geographical distribution, type of host and environmental conditions, different tick control measurements should be carried out in areas with high incidence of CCHF disease.

  6. Vectors of Crimean Congo Hemorrhagic Fever Virus in Iran

    Science.gov (United States)

    Telmadarraiy, Zakkyeh; Chinikar, Sadegh; Vatandoost, Hassan; Faghihi, Faezeh; Hosseini-Chegeni, Asadollah

    2015-01-01

    Background: Ticks are important vectors and reservoirs of Crimean Congo Hemorrhagic Fever (CCHF) virus. Human beings may be infected whenever the normal life cycle of the infected ticks on non-human vertebrate hosts is interrupted by the undesirable presence of humans in the cycle. A total of 26 species of Argasid and Ixodid ticks have been recorded in Iran; including nine Hyalomma, two Rhipicephalus, two Dermacentor, five Haemaphysalis, two Boophilus, one Ixodes and two Argas as well as three Ornithodoros species as blood sucking ectoparasites of livestock and poultries. The present paper reviews tick vectors of CCHF virus in Iran, focusing on the role of ticks in different provinces of Iran using reverse transcription polymerase chain reaction (RT-PCR) assay. Methods: During ten years study, 1054 tick specimens; including two species of Argasidae and 17 species of Ixodidae were examined for their infection to CCHF virus genome. The output of all studies as well as related publications were discussed in the current paper. Results: The results show that Rhipicephalus sanguineus, Hyalomma marginatum, H. anatolicum, H. asiaticum and H. dromedarii were known as the most frequent species which were positive for CCHF virus. Conclusion: The status of ticks which were positive for CCHF virus revealed that unlike the most common idea that Hyalomma species are the most important vectors of CCHF virus, other ticks including Rhipicephalus, Haemaphysalis and Dermacentor can be reservoir of this virus; thus, considering geographical distribution, type of host and environmental conditions, different tick control measurements should be carried out in areas with high incidence of CCHF disease. PMID:26623426

  7. Forest structure in low-diversity tropical forests: a study of Hawaiian wet and dry forests.

    Directory of Open Access Journals (Sweden)

    Rebecca Ostertag

    Full Text Available The potential influence of diversity on ecosystem structure and function remains a topic of significant debate, especially for tropical forests where diversity can range widely. We used Center for Tropical Forest Science (CTFS methodology to establish forest dynamics plots in montane wet forest and lowland dry forest on Hawai'i Island. We compared the species diversity, tree density, basal area, biomass, and size class distributions between the two forest types. We then examined these variables across tropical forests within the CTFS network. Consistent with other island forests, the Hawai'i forests were characterized by low species richness and very high relative dominance. The two Hawai'i forests were floristically distinct, yet similar in species richness (15 vs. 21 species and stem density (3078 vs. 3486/ha. While these forests were selected for their low invasive species cover relative to surrounding forests, both forests averaged 5->50% invasive species cover; ongoing removal will be necessary to reduce or prevent competitive impacts, especially from woody species. The montane wet forest had much larger trees, resulting in eightfold higher basal area and above-ground biomass. Across the CTFS network, the Hawaiian montane wet forest was similar to other tropical forests with respect to diameter distributions, density, and aboveground biomass, while the Hawai'i lowland dry forest was similar in density to tropical forests with much higher diversity. These findings suggest that forest structural variables can be similar across tropical forests independently of species richness. The inclusion of low-diversity Pacific Island forests in the CTFS network provides an ∼80-fold range in species richness (15-1182 species, six-fold variation in mean annual rainfall (835-5272 mm yr(-1 and 1.8-fold variation in mean annual temperature (16.0-28.4°C. Thus, the Hawaiian forest plots expand the global forest plot network to enable testing of ecological

  8. Surgical care for the direct and indirect victims of violence in the eastern Democratic Republic of Congo

    Directory of Open Access Journals (Sweden)

    Ford Nathan

    2010-04-01

    Full Text Available Abstract Background The provision of surgical assistance in conflict is often associated with care for victims of violence. However, there is an increasing appreciation that surgical care is needed for non-traumatic morbidities. In this paper we report on surgical interventions carried out by Médecins sans Frontières in Masisi, North Kivu, Democratic Republic of Congo to contribute to the scarce evidence base on surgical needs in conflict. Methods We analysed data on all surgical interventions done at Masisi district hospital between September 2007 and December 2009. Types of interventions are described, and logistic regression used to model associations with violence-related injury. Results 2869 operations were performed on 2441 patients. Obstetric emergencies accounted for over half (675, 57% of all surgical pathology and infections for another quarter (160, 14%. Trauma-related injuries accounted for only one quarter (681, 24% of all interventions; among these, 363 (13% were violence-related. Male gender (adjusted odds ratio (AOR = 20.0, p Conclusions In this study, most surgical interventions were unrelated to violent trauma and rather reflected the general surgical needs of a low-income tropical country. Programs in conflict zones in low-income countries need to be prepared to treat both the war-wounded and non-trauma related life-threatening surgical needs of the general population. Given the limited surgical workforce in these areas, training of local staff and task shifting is recommended to support broad availability of essential surgical care. Further studies into the surgical needs of the population are warranted, including population-based surveys, to improve program planning and resource allocation and the effectiveness of the humanitarian response.

  9. Surgical care for the direct and indirect victims of violence in the eastern Democratic Republic of Congo.

    Science.gov (United States)

    Chu, Kathryn; Havet, Philippe; Ford, Nathan; Trelles, Miguel

    2010-04-14

    The provision of surgical assistance in conflict is often associated with care for victims of violence. However, there is an increasing appreciation that surgical care is needed for non-traumatic morbidities. In this paper we report on surgical interventions carried out by Médecins sans Frontières in Masisi, North Kivu, Democratic Republic of Congo to contribute to the scarce evidence base on surgical needs in conflict. We analysed data on all surgical interventions done at Masisi district hospital between September 2007 and December 2009. Types of interventions are described, and logistic regression used to model associations with violence-related injury. 2869 operations were performed on 2441 patients. Obstetric emergencies accounted for over half (675, 57%) of all surgical pathology and infections for another quarter (160, 14%). Trauma-related injuries accounted for only one quarter (681, 24%) of all interventions; among these, 363 (13%) were violence-related. Male gender (adjusted odds ratio (AOR) = 20.0, p violence-related injury. Immediate peri-operative mortality was 0.2%. In this study, most surgical interventions were unrelated to violent trauma and rather reflected the general surgical needs of a low-income tropical country. Programs in conflict zones in low-income countries need to be prepared to treat both the war-wounded and non-trauma related life-threatening surgical needs of the general population. Given the limited surgical workforce in these areas, training of local staff and task shifting is recommended to support broad availability of essential surgical care. Further studies into the surgical needs of the population are warranted, including population-based surveys, to improve program planning and resource allocation and the effectiveness of the humanitarian response.

  10. Absolute water storages in the Congo River floodplains from integration of InSAR and satellite radar altimetry

    Science.gov (United States)

    Lee, H.; Yuan, T.; Jung, H. C.; Aierken, A.; Beighley, E.; Alsdorf, D. E.; Tshimanga, R.; Kim, D.

    2017-12-01

    Floodplains delay the transport of water, dissolved matter and sediments by storing water during flood peak seasons. Estimation of water storage over the floodplains is essential to understand the water balances in the fluvial systems and the role of floodplains in nutrient and sediment transport. However, spatio-temporal variations of water storages over floodplains are not well known due to their remoteness, vastness, and high temporal variability. In this study, we propose a new method to estimate absolute water storages over the floodplains by establishing relations between water depths (d) and water volumes (V) using 2-D water depth maps from the integration of Interferometric Synthetic Aperture Radar (InSAR) and altimetry measurements. We applied this method over the Congo River floodplains and modeled the d-V relation using a power function (note that d-V indicates relation between d and V, not d minus V), which revealed the cross-section geometry of the floodplains as a convex curve. Then, we combined this relation and Envisat altimetry measurements to construct time series of floodplain's absolute water storages from 2002 to 2011. Its mean annual amplitude over the floodplains ( 7,777 km2) is 3.860.59 km3 with peaks in December, which lags behind total water storage (TWS) changes from the Gravity Recovery and Climate Experiment (GRACE) and precipitation changes from Tropical Rainfall Measuring Mission (TRMM) by about one month. The results also exhibit inter-annual variability, with maximum water volume to be 5.9 +- 0.72 km3 in the wet year of 2002 and minimum volume to be 2.01 +- 0.63 km3 in the dry year of 2005. The inter-annual variation of water storages can be explained by the changes of precipitation from TRMM.

  11. Mapping and characterizing the vegetation types of the Democratic Republic of Congo using SPOT VEGETATION time series

    Science.gov (United States)

    Vancutsem, C.; Pekel, J.-F.; Evrard, C.; Malaisse, F.; Defourny, P.

    2009-02-01

    The need for quantitative and accurate information to characterize the state and evolution of vegetation types at a national scale is widely recognized. This type of information is crucial for the Democratic Republic of Congo, which contains the majority of the tropical forest cover of Central Africa and a large diversity of habitats. In spite of recent progress in earth observation capabilities, vegetation mapping and seasonality analysis in equatorial areas still represent an outstanding challenge owing to high cloud coverage and the extent and limited accessibility of the territory. On one hand, the use of coarse-resolution optical data is constrained by performance in the presence of cloud screening and by noise arising from the compositing process, which limits the spatial consistency of the composite and the temporal resolution. On the other hand, the use of high-resolution data suffers from heterogeneity of acquisition dates, images and interpretation from one scene to another. The objective of the present study was to propose and demonstrate a semi-automatic processing method for vegetation mapping and seasonality characterization based on temporal and spectral information from SPOT VEGETATION time series. A land cover map with 18 vegetation classes was produced using the proposed method that was fed by ecological knowledge gathered from botanists and reference documents. The floristic composition and physiognomy of each vegetation type are described using the Land Cover Classification System developed by the FAO. Moreover, the seasonality of each class is characterized on a monthly basis and the variation in different vegetation indicators is discussed from a phenological point of view. This mapping exercise delivers the first area estimates of seven different forest types, five different savannas characterized by specific seasonality behavior and two aquatic vegetation types. Finally, the result is compared to two recent land cover maps derived from

  12. Charcoal records reveal past occurrences of disturbances in the forests of the Kisangani region, Democratic Republic of the Congo

    Science.gov (United States)

    Tshibamba Mukendi, John; Hubau, Wannes; Ntahobavuka, Honorine; Boyemba Bosela, Faustin; De Cannière, Charles; Beeckman, Hans

    2014-05-01

    Past disturbances have modified local density, structure and floristic composition of Central African rainforests. As such, these perturbations represent a driving force for forest dynamics and they were presumably at the origin of present-day forest mosaics. One of the most prominent disturbances within the forest is fire, leaving behind charcoal as a witness of past forest dynamics. Quantification and identification of ancient charcoal fragments found in soil layers (= pedoanthracology) allows a detailed reconstruction of forest history, including the possible occurrence of past perturbations. The primary objective of this study is to present palaeoenvironmental evidence for the existence of past disturbances in the forests of the Kisangani region (Democratic Republic of the Congo) using a pedoanthracological approach. We quantified and identified charcoal fragments from pedoanthracological excavations in the Yangambi, Yoko, Masako and Kole forest regions. Charcoal sampling was conducted in pit intervals of 10 cm, whereby pottery fragments were also registered and quantified. Floristic identifications were conducted using former protocols based on wood anatomy, which is largely preserved after charcoalification. 14 excavations were conducted and charcoal was found in most pit intervals. Specifically, 52 out of 56 sampled intervals from the Yangambi forest contained charcoal, along with 47 pit intervals from the Yoko forest reserve, 34 pit intervals from the Masako forest and 16 from the Kole forest. Highest specific anthracomasses were recorded in Yoko (167 mg charcoal per kg soil), followed by Yangambi (133 mg/kg), Masako (71,89 mg/kg) and finally Kole (42,4 mg/kg). Charcoal identifications point at a manifest presence of the family of Fabaceae (Caesalpinioideae). This family is characteristic for the tropical humid rainforest. The presence of charcoal fragments from these taxa, associated with pottery sherds on different depths within the profiles, suggests

  13. Malaria and Tropical Travel

    Centers for Disease Control (CDC) Podcasts

    2008-05-15

    Malaria is a serious mosquito-borne disease that can lead to death. This podcast discusses malaria risk when traveling to tropical areas, as well as how to protect yourself and your family from malaria infection.  Created: 5/15/2008 by National Center for Zoonotic, Vector-Borne, and Enteric Diseases (NCZVED).   Date Released: 5/29/2008.

  14. Leaf litter decomposition rates increase with rising mean annual temperature in Hawaiian tropical montane wet forests

    Directory of Open Access Journals (Sweden)

    Lori D. Bothwell

    2014-12-01

    Full Text Available Decomposing litter in forest ecosystems supplies nutrients to plants, carbon to heterotrophic soil microorganisms and is a large source of CO2 to the atmosphere. Despite its essential role in carbon and nutrient cycling, the temperature sensitivity of leaf litter decay in tropical forest ecosystems remains poorly resolved, especially in tropical montane wet forests where the warming trend may be amplified compared to tropical wet forests at lower elevations. We quantified leaf litter decomposition rates along a highly constrained 5.2 °C mean annual temperature (MAT gradient in tropical montane wet forests on the Island of Hawaii. Dominant vegetation, substrate type and age, soil moisture, and disturbance history are all nearly constant across this gradient, allowing us to isolate the effect of rising MAT on leaf litter decomposition and nutrient release. Leaf litter decomposition rates were a positive linear function of MAT, causing the residence time of leaf litter on the forest floor to decline by ∼31 days for each 1 °C increase in MAT. Our estimate of the Q10 temperature coefficient for leaf litter decomposition was 2.17, within the commonly reported range for heterotrophic organic matter decomposition (1.5–2.5 across a broad range of ecosystems. The percentage of leaf litter nitrogen (N remaining after six months declined linearly with increasing MAT from ∼88% of initial N at the coolest site to ∼74% at the warmest site. The lack of net N immobilization during all three litter collection periods at all MAT plots indicates that N was not limiting to leaf litter decomposition, regardless of temperature. These results suggest that leaf litter decay in tropical montane wet forests may be more sensitive to rising MAT than in tropical lowland wet forests, and that increased rates of N release from decomposing litter could delay or prevent progressive N limitation to net primary productivity with climate warming.

  15. A legacy of low-impact logging does not elevate prevalence of potentially pathogenic protozoa in free-ranging gorillas and chimpanzees in the Republic of Congo: logging and parasitism in African apes.

    Science.gov (United States)

    Gillespie, Thomas R; Morgan, David; Deutsch, J Charlie; Kuhlenschmidt, Mark S; Salzer, Johanna S; Cameron, Kenneth; Reed, Trish; Sanz, Crickette

    2009-12-01

    Many studies have examined the long-term effects of selective logging on the abundance and diversity of free-ranging primates. Logging is known to reduce the abundance of some primate species through associated hunting and the loss of food trees for frugivores; however, the potential role of pathogens in such primate population declines is largely unexplored. Selective logging results in a suite of alterations in host ecology and forest structure that may alter pathogen dynamics in resident wildlife populations. In addition, environmental pollution with human fecal material may present a risk for wildlife infections with zoonotic protozoa, such as Cryptosporidium and Giardia. To better understand this interplay, we compared patterns of infection with these potentially pathogenic protozoa in sympatric western lowland gorillas (Gorilla gorilla gorilla) and chimpanzees (Pan troglodytes troglodytes) in the undisturbed Goualougo Triangle of Nouabalé-Ndoki National Park and the adjacent previously logged Kabo Concession in northern Republic of Congo. No Cryptosporidium infections were detected in any of the apes examined and prevalence of infection with Giardia was low (3.73% overall) and did not differ between logged and undisturbed forest for chimpanzees or gorillas. These results provide a baseline for prevalence of these protozoa in forest-dwelling African apes and suggest that low-intensity logging may not result in long-term elevated prevalence of potentially pathogenic protozoa.

  16. [Tropical causes of epilepsy].

    Science.gov (United States)

    Carod-Artal, F J

    Eighty-five percent of all epileptics live in tropical regions. Prenatal risk factors, traumatic brain injuries and different parasitic infestations of the central nervous system (CNS) are the reasons behind the high prevalence of epilepsy. This work reviews the main parasitic infestations causing epilepsy in the tropics. Neurocysticercosis is the main cause of focal epilepsy in early adulthood in endemic areas (30-50%). All the phases of cysticerci (viable, transitional and calcified) are associated with epileptic seizures. Anti-cysticercus treatment helps get rid of cysticerci faster and reduces the risk of recurrence of seizures in patients with viable cysts. Symptomatic epilepsy can be the first manifestation of neuroschistosomiasis in patients without any systemic symptoms. The pseudotumoral form can trigger seizures secondary to the presence of granulomas and oedemas in the cerebral cortex. The eggs of Schistosoma japonicum are smaller, reach the CNS more easily and trigger epileptic seizures more frequently. Toxocariasis and sparganosis are other parasitic infestations that can give rise to symptomatic seizures. The risk factors for suffering chronic epilepsy after cerebral malaria are a positive familial history of epilepsy and a history of episodes of fever and cerebral malaria that began with coma or which progressed with multiple, prolonged epileptic seizures. About 20% of patients with cerebral infarction secondary to Chagas disease present late vascular epilepsy as a complication. Very few studies have been conducted to examine the prognosis, risk of recurrence and modification of the natural course of seizures associated with tropical parasitic infestations, except for the case of neurocysticercosis.

  17. Mineralogic maturity of modern sand along a high-energy tropical coast: Baixada de Jacarepaguá, Rio de Janeiro, Brazil

    Science.gov (United States)

    Savage, K. M.; de Cesero, P.; Potter, P. E.

    Quarts arenites overlying crystalline basement are fairly common in the geologic record. A modern analog is provided in coastal Brazil where a small tropical lowland is bordered by abrupt, Precambrian granitic and gneissic mountains of the Serra do Mar. Nine different sedimentary environments were sampled, 57 sands were studied petrographically, and 8 complete chemical analyses were made. Here, arkosic river sands pass seaward into well defined, quartz-rich, stranded beach ridges and pure quartz arenites of the modern beach and shelf. Strong inshore wave power combined with tropical weathering seem to be the principal factors for this change. Tropical weathering also converted surface samples of arkosic Pliocene fan deposits into residual quartz arenites. Implications for the paleotectonic and paleoclimatic interpretation of ancient sandstones are also discussed.

  18. Functional trait composition of aquatic plants can serve to disentangle multiple interacting stressors in lowland streams

    Energy Technology Data Exchange (ETDEWEB)

    Baattrup-Pedersen, Annette, E-mail: abp@bios.au.dk [Department of Bioscience, Aarhus University, Vejlsøvej 25, P.O. Box 314, DK-8600 Silkeborg (Denmark); Göthe, Emma [Department of Bioscience, Aarhus University, Vejlsøvej 25, P.O. Box 314, DK-8600 Silkeborg (Denmark); Riis, Tenna [Department of Bioscience, Aarhus University, Ole Worms Allé 1, Building 1135, Room 217, DK-8000 Aarhus C (Denmark); O' Hare, Matthew T. [Centre for Ecology and Hydrology, Bush Estate, Penicuik EH26 0QB (United Kingdom)

    2016-02-01

    Historically, close attention has been paid to negative impacts associated with nutrient loads to streams and rivers, but today hydromorphological alterations are considered increasingly implicated when lowland streams do not achieve good ecological status. Here, we explore if trait-abundance patterns of aquatic plants change along gradients in hydromorphological degradation and eutrophication in lowland stream sites located in Denmark. Specifically, we hypothesised that: i) changes in trait-abundance patterns occur along gradients in hydromorphological degradation and ii) trait-abundance patterns can serve to disentangle effects of eutrophication and hydromorphological degradation in lowland streams reflecting that the mechanisms behind changes differ. We used monitoring data from a total of 147 stream reaches with combined data on aquatic plant species abundance, catchment land use, hydromorphological alterations (i.e. planform, cross section, weed cutting) and water chemistry parameters. Traits related to life form, dispersal, reproduction and survival together with ecological preference values for nutrients and light (Ellenberg N and L) were allocated to 41 species representing 79% of the total species pool. We found clear evidence that habitat degradation (hydromorphological alterations and eutrophication) mediated selective changes in the trait-abundance patterns of the plant community. Specific traits could distinguish hydromorphological degradation (free-floating, surface; anchored floating leaves; anchored heterophylly) from eutrophication (free-floating, submerged; leaf area). We provide a conceptual framework for interpretation of how eutrophication and hydromorphological degradation interact and how this is reflected in trait-abundance patterns in aquatic plant communities in lowland streams. Our findings support the merit of trait-based approaches in biomonitoring as they shed light on mechanisms controlling structural changes under environmental

  19. Functional trait composition of aquatic plants can serve to disentangle multiple interacting stressors in lowland streams

    International Nuclear Information System (INIS)

    Baattrup-Pedersen, Annette; Göthe, Emma; Riis, Tenna; O'Hare, Matthew T.

    2016-01-01

    Historically, close attention has been paid to negative impacts associated with nutrient loads to streams and rivers, but today hydromorphological alterations are considered increasingly implicated when lowland streams do not achieve good ecological status. Here, we explore if trait-abundance patterns of aquatic plants change along gradients in hydromorphological degradation and eutrophication in lowland stream sites located in Denmark. Specifically, we hypothesised that: i) changes in trait-abundance patterns occur along gradients in hydromorphological degradation and ii) trait-abundance patterns can serve to disentangle effects of eutrophication and hydromorphological degradation in lowland streams reflecting that the mechanisms behind changes differ. We used monitoring data from a total of 147 stream reaches with combined data on aquatic plant species abundance, catchment land use, hydromorphological alterations (i.e. planform, cross section, weed cutting) and water chemistry parameters. Traits related to life form, dispersal, reproduction and survival together with ecological preference values for nutrients and light (Ellenberg N and L) were allocated to 41 species representing 79% of the total species pool. We found clear evidence that habitat degradation (hydromorphological alterations and eutrophication) mediated selective changes in the trait-abundance patterns of the plant community. Specific traits could distinguish hydromorphological degradation (free-floating, surface; anchored floating leaves; anchored heterophylly) from eutrophication (free-floating, submerged; leaf area). We provide a conceptual framework for interpretation of how eutrophication and hydromorphological degradation interact and how this is reflected in trait-abundance patterns in aquatic plant communities in lowland streams. Our findings support the merit of trait-based approaches in biomonitoring as they shed light on mechanisms controlling structural changes under environmental

  20. Evaluation of sugar-cane bagasse as bioadsorbent in the textile wastewater treatment contaminated with carcinogenic congo red dye

    Directory of Open Access Journals (Sweden)

    Aline Sartório Raymundo

    2010-08-01

    Full Text Available A methodology involving sugar cane bagasse bioadsorbent was developed in order to remove the carcinogenic congo red dye from aqueous medium. The results showed high efficiency with retention of 64 ± 6% in synthetic congo red solution and 94 ± 5% in effluent enriched with congo red, at 10.0 g of the bioadsorbent. The adsorption system provided a maximum adsorption capacity of 4.43 mg/g. Tests showed independence adsorption properties, when compared with the column flow rates. The treatment units could be operated with flexibility. From the results, it was possible to conclude that sugar cane bagasse could be an adequate bioadsorbent.Neste trabalho foi desenvolvida uma metodologia de remoção do corante carcinogênico congo red de sistemas aquosos. Os resultados mostraram uma elevada eficiência de remoção sendo de 64 ± 6% para soluções sintéticas de vermelho congo, e 94 ± 5% para efluente industrial enriquecido com vermelho congo utilizando 10 g de bioadsorvente. A capacidade máxima adsotiva encontrada foi de 4,43 mg/g. Os testes de percolação revelaram independência das porcentagens adsortivas em relação às vazões das colunas. Estes resultados indicam viabilidade de uso do bagaço de cana-de-açucar no tratamento de efluentes contendo o congo red.

  1. Tropical Peatland Geomorphology and Hydrology

    Science.gov (United States)

    Cobb, A.; Harvey, C. F.

    2017-12-01

    Tropical peatlands cover many low-lying areas in the tropics. In tropical peatlands, a feedback between hydrology, landscape morphology, and carbon storage causes waterlogged organic matter to accumulate into gently mounded land forms called peat domes over thousands of years. Peat domes have a stable morphology in which peat production is balanced by loss and net precipitation is balanced by lateral flow, creating a link between peatland morphology, rainfall patterns and drainage networks. We show how landscape morphology can be used to make inferences about hydrologic processes in tropical peatlands. In particular, we show that approaches using simple storage-discharge relationships for catchments are especially well suited to tropical peatlands, allowing river forecasting based on peatland morphology in catchments with tropical peatland subcatchments.

  2. Commitment to a Lady’s First WIN : Banking Innovation in the Democratic Republic of Congo

    OpenAIRE

    Vivian Awiti Owuor

    2011-01-01

    Doing business is challenging in the Democratic Republic of Congo and presents opportunities for innovative approaches to banking, especially for micro, small, and medium enterprises (MSMEs) - and particularly for women entrepreneurs. But it is getting easier, thanks to innovating banking. This SmartLesson reviews some of the early lessons learned from the ongoing implementation of a Women...

  3. Congo, de missie en de literatuur: Over David van Reybrouck, J. G. ...

    African Journals Online (AJOL)

    However, the travel books written by Lieve Joris and Bart Castelein and the play Missie (Mission) written by David van Reybrouck (2007) sketched a positive and nostalgic image of the missionary. Keywords: Dutch (post)colonial literature, Congo, missionaries, colonialism. Tydskrif vir Letterkunde Vol. 46 (1) 2009: pp. 123- ...

  4. Les effets du changement climatique dans le bassin du Congo : la ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    22 avr. 2016 ... Dans le bassin du fleuve Congo, plus de 80 % des habitants vivent exclusivement de l'agriculture, de la pêche, de l'élevage et de la cueillette, qui sont des activités largement tributaires du climat.

  5. Heath sector network governance and State-building in South Kivu, Democratic Republic of Congo

    NARCIS (Netherlands)

    Bwimana, Aembe

    2017-01-01

    Longstanding patterns of interaction exist between state and non-state actors seeking to improve public health in Democratic Republic of Congo (DRC). DRC is a weak state, and, in many cases, private actors have stepped in to fill the void created by the lack of state health care provision. However,

  6. Mapping monkeypox transmission risk through time and space in the Congo Basin

    Science.gov (United States)

    Nakazawa, Yoshinori J.; Lash, R. Ryan; Carroll, Darin S.; Damon, Inger K.; Karem, Kevin L.; Reynolds, Mary G.; Osorio, Jorge E.; Rocke, Tonie E.; Malekani, Jean; Muyembe, Jean-Jacques; Formenty, Pierre; Peterson, A. Townsend

    2013-01-01

    Monkeypox is a major public health concern in the Congo Basin area, with changing patterns of human case occurrences reported in recent years. Whether this trend results from better surveillance and detection methods, reduced proportions of vaccinated vs. non-vaccinated human populations, or changing environmental conditions remains unclear. Our objective is to examine potential correlations between environment and transmission of monkeypox events in the Congo Basin. We created ecological niche models based on human cases reported in the Congo Basin by the World Health Organization at the end of the smallpox eradication campaign, in relation to remotely-sensed Normalized Difference Vegetation Index datasets from the same time period. These models predicted independent spatial subsets of monkeypox occurrences with high confidence; models were then projected onto parallel environmental datasets for the 2000s to create present-day monkeypox suitability maps. Recent trends in human monkeypox infection are associated with broad environmental changes across the Congo Basin. Our results demonstrate that ecological niche models provide useful tools for identification of areas suitable for transmission, even for poorly-known diseases like monkeypox.

  7. A model to predict when a cholera outbreak might hit the Congo

    Science.gov (United States)

    Schultz, Colin

    2014-09-01

    In 2011, as many as 600,000 people in 58 countries contracted cholera, with thousands succumbing to the disease. In most countries, cholera is rare. In others, like the Democratic Republic of the Congo, cholera is an endemic threat, always lurking in the background waiting for the right set of conditions to spark an outbreak.

  8. A case report of crimean congo hemorrhagic Fever in ostriches in iran

    DEFF Research Database (Denmark)

    Mostafavi, Ehsan; Chinikar, Sadegh; Moradi, Maryam

    2013-01-01

    Crimean Congo hemorrhagic fever (CCHF) is a viral zoonosis, which is usually transmitted via tick bites or close contact with infected blood or tissue. This disease can cause a case fatality rate of up to 25%-30% in humans. CCHF Infection in birds is less documented. An ostrich can reproduce...

  9. Governing Congo Basin forests in a changing climate: actors, discourses and institutions for adaptation and mitigation

    NARCIS (Netherlands)

    Somorin, O.A.

    2014-01-01

    Governing Congo Basin Forests in a Changing Climate: Actors, Discourses and Institutions for Adaptation and Mitigation

    OA Somorin

    Abstract

    The thesis deals with the central question of the governance processes of making

  10. Les écoles au Congo belge en 1924. Le rapport De Jonghe ...

    African Journals Online (AJOL)

    enseignement au Congo, exprimé dans le projet de 1922, De Jonghe a entrepris un voyage de reconnaissance en 1924. Une nouvelle version du Projet paraissait en 1925 et la version définitive est approuvée en 1928 et publiée en 1929.

  11. Scorpion envenomation in pygmies from Democratic Republic of Congo, the example of Pelenge Center, Lomela, DRC

    Directory of Open Access Journals (Sweden)

    E Biezakala Mudiandambu

    2012-01-01

    Full Text Available In a survey among the pygmies of central Democratic Republic of Congo, the incidence of scorpion stings seemed very high with a severity greater than expected. Species responsible were not identified. Specific studies are needed to clarify the risk emerging in the equatorial African forest.

  12. Enhanced adsorptive degradation of Congo red in aqueous solutions using polyaniline/Fe0 composite nanofibers

    CSIR Research Space (South Africa)

    Bhaumik, M

    2015-01-01

    Full Text Available In this study, a simple approach was described for the fabrication of composite nanofibers (CNFs) of polyaniline/Fe0 (PANI/Fe0) using a template-free method for the reductive degradation and removal of Congo red (CR) from aqueous solutions. The PANI...

  13. Phytochemical analysis and biological evaluation of selected African propolis samples from Cameroon and Congo

    NARCIS (Netherlands)

    Papachroni, D.; Graikou, K.; Kosalec, I.; Damianakos, H.; Ingram, V.J.; Chinou, I.

    2015-01-01

    The objective of this study was the chemical analysis of four selected samples of African propolis (Congo and Cameroon) and their biological evaluation. Twenty-one secondary metabolites belonging to four different chemical groups were isolated from the 70% ethanolic extracts of propolis and their

  14. An outbreak of West Nile fever among migrants in Kisangani, Democratic Republic of Congo.

    NARCIS (Netherlands)

    Y.A. Nur; J. Groen (Jan); H. Heuvelmans; W. Tuynman; C. Copra (Cederick); A.D.M.E. Osterhaus (Albert)

    1999-01-01

    textabstractIn February 1998, an outbreak of acute febrile illness was reported from the Kapalata military camp in Kisangani, the Democratic Republic of Congo. The illness was characterized by an acute onset of fever associated with severe headache, arthralgia, backache, neurologic signs, abdominal

  15. An outbreak of West Nile fever among migrants in Kisangani, Democratic Republic of Congo

    NARCIS (Netherlands)

    Y.A. Nur; J. Groen (Jan); H. Heuvelmans; W. Tuynman; C. Copra (Cederick); A.D.M.E. Osterhaus (Albert)

    1999-01-01

    textabstractIn February 1998, an outbreak of acute febrile illness was reported from the Kapalata military camp in Kisangani, the Democratic Republic of Congo. The illness was characterized by an acute onset of fever associated with severe headache, arthralgia, backache, neurologic

  16. Profiling climate change vulnerability of forest indigenous communities in the Congo Basin

    NARCIS (Netherlands)

    Nkem, J.N.; Somorin, O.A.; Jum, C.; Idinoba, M.E.; Bele, Y.M.; Sonwa, D.J.

    2013-01-01

    The livelihood strategies of indigenous communities in the Congo Basin are inseparable from the forests, following their use of forest ecosystem goods and services (FEGS). Climate change is expected to exert impacts on the forest and its ability to provide FEGS. Thus, human livelihoods that depend

  17. Leopard-men of the Congo in literature and popular imagination ...

    African Journals Online (AJOL)

    The Anyoto leopard-men, a society from eastern Congo, operated between approximately 1890 and 1935. Until now the history of the leopard-men has inspired representations of Central Africa as a barbaric and disorderly place, and the idea that a secret association of men attacked innocent people and ate their limbs ...

  18. Gestion des espaces publics au Congo-Brazzaville: le cas des ...

    African Journals Online (AJOL)

    The issue of public spaces in Congo-Brazzaville is at the heart of municipal political debates. At the level of public transport, the management of public spaces remains above all in the hands of the mayor's office and municipal councillors. The agreements between these authorities and the contractors running public ...

  19. Managing (Fiscally) Resource Windfalls : Exploring Policy Options for the Democratic Republic of Congo

    OpenAIRE

    Pinto-Moreira, Emmanuel

    2016-01-01

    How should resource-dependent countries respond (fiscally) to resource price volatility? This note studies what determines revenue allocation between a "spend today" strategy and a "save now-spend tomorrow" approach in the context of the Democratic Republic of Congo. It uses a three-sector model in which public infrastructure investment has tangible benefits for private production and inve...

  20. Gender implications of forest product value chains in the Congo basin

    NARCIS (Netherlands)

    Ingram, V.; Schure, J.M.; Tieguhong, J.C.; Ndoye, O.; Awono, A.; Iponga, D.M.

    2014-01-01

    Activities and roles in value chains of forest products in the Congo Basin are highly gendered, varying with the product's characteristics, the segment of the chain and customary regulations and norms. High-value products are primarily male-harvested when customary rules govern tenure and access,

  1. "New Education" for the Congo? The Indigenist Approach, New Education and Prescriptive Pedagogy

    Science.gov (United States)

    Depaepe, Marc; Simon, Frank; Vinck, Honoré

    2015-01-01

    This article responds to a question put forward approximately a decade ago by the history of education research group at the Katholieke Universiteit Leuven: Did the child-centred ideas of New Education, as promoted by Ovide Decroly, influence the education policy in the former Belgian colony of Congo? Naturally, ideas were circulating that could…

  2. On the occurrence of bryophytes and macrolichens in different lowland rain forest types at Mabura Hill, Guyana

    OpenAIRE

    Cornelissen, J. Hans C.; Gradstein, Stephan Robbert

    1990-01-01

    A floristic and ecological study of bryophytes and macrolichens in different lowland rain forest types around Mabura Hill, Guyana, South America, yielded 170 species: 52 mosses, 82 liverworts and 36 macrolichens. Lejeuneaceae account for about 30% of the species and are the dominant cryptogamic family of the lowland rain forest. Special attention was paid to the flora of the forest canopy, by using mountaineering techniques. It appeared that 50% of the bryophyte species and 86% of the macroli...

  3. Medical Orders: Catholic and Protestant Missionary Medicine in the Belgian Congo 1880-1940

    Directory of Open Access Journals (Sweden)

    Sokhieng Au

    2017-03-01

    Full Text Available The history of religious missions and the provisioning of western medical care in the region that was known as the Congo Free State and later the Belgian Congo reveals the complicated dynamics between competing religious missions vis à vis the Belgian colonial state. This essay highlights divisions between identities and purposes of different religious groups in medical care provisioning, focusing on the divide between the Catholic and Protestant churches. Because most Protestant missions in the Congo were American or British, the medical care provided by the Protestant church was outside of, and sometimes at odds with, the Belgian colonial state until the 1920s. In contrast, the Catholic Church served in an auxiliary role in the colonial state’s medical infrastructure. This was not an ideal situation, leading Catholic leaders to attempt to rework the church’s role in medical provisioning. Ultimately, mission, medicine, and empire were not always comfortable bedfellows. Medische Orders: katholieke en protestantse missiegeneeskunde in de Belgische Congo 1880-1940De geschiedenis van de religieuze missies en het voorzien in westerse medische gezondheidszorg in de Congo Vrijstaat – later de Belgische Congo – onthult de ingewikkelde dynamiek tussen de concurrerende religieuze missies vis à vis de Belgische koloniale staat. Dit artikel belicht verschillende religieuze groepen die medische zorg verleenden in deze regio en hun verdeeldheid inzake identiteiten en doelen. Hierbij wordt vooral gefocust op de tweedracht tussen de katholieke en protestantse kerk. Omdat de meeste protestantse missies die in de Congo gevestigd waren uit Amerika of Engeland kwamen, werd de medische zorg die zij verstrekten vaak buiten de Belgische koloniale staat om geleverd en leefden staat en protestantse kerk tot in de jaren 1920 soms op gespannen voet met elkaar. Dit staat in sterk contrast tot de katholieke kerk die wat betreft medische infrastructuur juist een

  4. Ranging and grouping patterns of a western lowland gorilla group at Bai Hokou, Central African Republic.

    Science.gov (United States)

    Remis, M J

    1997-01-01

    The ranging and grouping patterns of a gorilla group were studied during 27 months from 1990-1992 at the Bai Hokou study site, Central African Republic. The study group ranged far daily (average = 2.3 km/day) and had a large home range (22.9 km2), relative to mountain gorillas, and ranging patterns differed between years. During 1990-1992, the bimale study group foraged less cohesively and had more flexible grouping patterns than mountain gorillas. The study group sometimes split into two distinct foraging subgroups, each led by a silverback, and these subgroups occasionally slept apart (mean = 950 m apart). Lowland gorillas rely on many of the same fruit resources as sympatric chimpanzees, and under certain demographic situations gorillas, like sympatric chimpanzees, may adapt their foraging group size to reduce intragroup feeding competition. However, the fiber content of the lowland gorilla diet likely relaxes constraints on foraging party size and facilitates group cohesion relative to chimpanzees.

  5. Early Middle Formative Occupation in the Central Maya Lowlands: Recent Evidence from Cahal Pech, Belize

    Directory of Open Access Journals (Sweden)

    Jaime Awe

    1990-11-01

    Full Text Available After more than half a century of intensive archaeological research the early Middle Formative (or Middle Preclassic period (1000-600 B.C. continues to be one of the most enigmatic eras in the study of Lowland Maya prehistory. While several factors contribte to this situation, the primary cause for this obscurity lies in the fact that few sites have produced either contextual or stratigraphic evidence of occupation during this phase (Rice 1976; Andrews 1988. Concsequently, any new site with evidence of Middle Formative occupation can contribute substantially to our limited knowledge of this pioneering stage of the lowland Maya. This paper introduces one such site, Cahal Pech, where recent investigations have uncovered a stratigraphic sequence that tentatively spans the early Middle Formative to the Late Classic period. It provides a preliminary description, of the site's early Middle Formative configuration and briefly discusses its possible regional affiliation.

  6. Lowland rice yield estimates based on air temperature and solar radiation

    International Nuclear Information System (INIS)

    Pedro Júnior, M.J.; Sentelhas, P.C.; Moraes, A.V.C.; Villela, O.V.

    1995-01-01

    Two regression equations were developed to estimate lowland rice yield as a function of air temperature and incoming solar radiation, during the crop yield production period in Pindamonhangaba, SP, Brazil. The following rice cultivars were used: IAC-242, IAC-100, IAC-101 and IAC-102. The value of optimum air temperature obtained was 25.0°C and of optimum global solar radiation was 475 cal.cm -2 , day -1 . The best agrometeorological model was the one that related least deviation of air temperature and solar radiation in relation to the optimum value obtained through a multiple linear regression. The yield values estimated by the model showed good fit to actual yields of lowland rice (less than 10%). (author) [pt

  7. Estimation of arboreal lichen biomass available to woodland caribou in Hudson Bay lowland black spruce sites

    Directory of Open Access Journals (Sweden)

    Sarah K. Proceviat

    2003-04-01

    Full Text Available An arboreal lichen index to be utilized in assessing woodland caribou habitat throughout northeastern Ontario was developed. The "index" was comprised of 5 classes, which differentiated arboreal lichen biomass on black spruce trees, ranging from maximal quantities of arboreal lichen (class 5 to minimal amounts of arboreal lichen (class 1. This arboreal lichen index was subsequently used to estimate the biomass of arboreal lichen available to woodland caribou on lowland black spruce sites ranging in age from 1 year to 150 years post-harvest. A total of 39 sites were assessed and significant differences in arboreal lichen biomass were found, with a positive linear relationship between arboreal lichen biomass and forest age. It is proposed that the index be utilized by government and industry as a means of assessing the suitability of lowland black spruce habitat for woodland caribou in this region.

  8. Tropical Peat and Peatland Development in the Floodplains of the Greater Pamba Basin, South-Western India during the Holocene.

    Science.gov (United States)

    Kumaran, Navnith K P; Padmalal, Damodaran; Limaye, Ruta B; S, Vishnu Mohan; Jennerjahn, Tim; Gamre, Pradeep G

    2016-01-01

    Holocene sequences in the humid tropical region of Kerala, South-western (SW) India have preserved abundance of organic-rich sediments in the form of peat and its rapid development in a narrow time frame towards Middle Holocene has been found to be significant. The sub-coastal areas and flood plains of the Greater Pamba Basin have provided palaeorecords of peat indicating that the deposits are essentially formed within freshwater. The combination of factors like stabilized sea level and its subsequent fall since the Middle Holocene, topographic relief and climatic conditions led to rapid peat accumulation across the coastal lowlands. The high rainfall and massive floods coupled with a rising sea level must have inundated > 75% of the coastal plain land converting it into a veritable lagoon-lake system that eventually led to abrupt termination of the forest ecosystem and also converted the floodplains into peatland where accumulation of peat almost to 2.0-3.0 m thickness in coastal lowlands and river basins during the shorter interval in the Middle Holocene. Vast areas of the coastal plains of Kerala have been converted into carbon rich peatland during the Middle Holocene and transforming the entire coastal stretch and associated landforms as one of the relatively youngest peatlands in the extreme southern tip of India. Unlike the uninterrupted formation of peatlands of considerable extent during the Holocene in Southeast Asia, the south Peninsular Indian region has restricted and short intervals of peatlands in the floodplains and coastal lowlands. Such a scenario is attributed to the topographic relief of the terrain and the prevailing hydrological regimes and environmental conditions as a consequence of monsoon variability since Middle Holocene in SW India. Considering the tropical coastal lowlands and associated peatlands are excellent repositories of carbon, they are very important for regional carbon cycling and habitat diversity. The alarming rate of land

  9. Tropical Peat and Peatland Development in the Floodplains of the Greater Pamba Basin, South-Western India during the Holocene.

    Directory of Open Access Journals (Sweden)

    Navnith K P Kumaran

    Full Text Available Holocene sequences in the humid tropical region of Kerala, South-western (SW India have preserved abundance of organic-rich sediments in the form of peat and its rapid development in a narrow time frame towards Middle Holocene has been found to be significant. The sub-coastal areas and flood plains of the Greater Pamba Basin have provided palaeorecords of peat indicating that the deposits are essentially formed within freshwater. The combination of factors like stabilized sea level and its subsequent fall since the Middle Holocene, topographic relief and climatic conditions led to rapid peat accumulation across the coastal lowlands. The high rainfall and massive floods coupled with a rising sea level must have inundated > 75% of the coastal plain land converting it into a veritable lagoon-lake system that eventually led to abrupt termination of the forest ecosystem and also converted the floodplains into peatland where accumulation of peat almost to 2.0-3.0 m thickness in coastal lowlands and river basins during the shorter interval in the Middle Holocene. Vast areas of the coastal plains of Kerala have been converted into carbon rich peatland during the Middle Holocene and transforming the entire coastal stretch and associated landforms as one of the relatively youngest peatlands in the extreme southern tip of India. Unlike the uninterrupted formation of peatlands of considerable extent during the Holocene in Southeast Asia, the south Peninsular Indian region has restricted and short intervals of peatlands in the floodplains and coastal lowlands. Such a scenario is attributed to the topographic relief of the terrain and the prevailing hydrological regimes and environmental conditions as a consequence of monsoon variability since Middle Holocene in SW India. Considering the tropical coastal lowlands and associated peatlands are excellent repositories of carbon, they are very important for regional carbon cycling and habitat diversity. The

  10. What´s in the tank? Nematodes and other major components of the meiofauna of bromeliad phytotelms in lowland Panama.

    Science.gov (United States)

    Zotz, Gerhard; Traunspurger, Walter

    2016-03-15

    Nematodes are a very diverse and extremely abundant group of animals, but their occurrence in the tropics is surprisingly little understood. We investigated the meiofauna of epiphytic tank bromeliads in the lowlands of Panama with particular emphasis on nematodes. We encountered 89 morphospecies of nematodes in 54 bromeliad tanks, which were sampled in the wet and the dry season. Rotifers were by far the most abundant group in both the dry and the wet season (with up to 960 individual ml(-1)), followed by nematodes, annelids and harpacticoid copepods. Individual plants hosted up to 25 nematode species. These nematodes represented a diversity of feeding guilds, suction-feeders and deposit-feeders being most abundant. The relative abundances of feeding-types of nematodes differed considerably in the wet and dry season. Both species richness and abundance were strongly correlated with the size of the phytotelms and the season, while species diversity assessed with the Shannon-index was affected by neither of the two. This is the first study with a particular focus on the diversity of nematodes in tank bromeliads. We document a meiofauna of considerable abundance and diversity, which suggests important functional roles in ecological processes such as decomposition, which in turn warrants further study.

  11. Turbidity and plant growth in large slow-flowing lowland rivers: progress report March 1989

    OpenAIRE

    Marker, A.F.H.

    1989-01-01

    The River Great Ouse is a highly managed large lowland river in eastern England. It drains rich arable land in the Midlands and Eastern England and over the years nutrient concentrations have increased and there is a general perception that the clarity of the water has decreased. The main river channels have been dredged a number of times partly for flood control reasons but also for recreational boating and navigation activities. The period covered by this first report has been used to devel...

  12. Geomorphology Drives Amphibian Beta Diversity in Atlantic Forest Lowlands of Southeastern Brazil

    OpenAIRE

    Luiz, Amom Mendes; Le?o-Pires, Thiago Augusto; Sawaya, Ricardo J.

    2016-01-01

    Beta diversity patterns are the outcome of multiple processes operating at different scales. Amphibian assemblages seem to be affected by contemporary climate and dispersal-based processes. However, historical processes involved in present patterns of beta diversity remain poorly understood. We assess and disentangle geomorphological, climatic and spatial drivers of amphibian beta diversity in coastal lowlands of the Atlantic Forest, southeastern Brazil. We tested the hypothesis that geomorph...

  13. TO THE KNOWLEDGE OF POORLY KNOWN CARABIDS (COLEOPTERA, CARABIDAE OF THE CASPIAN LOWLAND

    Directory of Open Access Journals (Sweden)

    I. A. Belousov

    2013-01-01

    Full Text Available New data are given on the distribution of the carabids Clivinopsis conicicollis Reitter and Anaulacus (Aephnidius ruficornis Chaudoir in the Caspain Lowland . Photographs of both species are provided and their distribution is mapped. C. conicicollis is for the first time recorded for Daghestan while members of the genus Anaulacus were not previously known for Russia, Azerbaidjan, Iran, and Turkmenistan. A determination key is given to distinguish between species of the genus Anaulacus and members of the related genus Masoreus Dejean.

  14. Hydrology and phosphorus transport simulation in a lowland polder by a coupled modeling system.

    Science.gov (United States)

    Yan, Renhua; Huang, Jiacong; Li, Lingling; Gao, Junfeng

    2017-08-01

    Modeling the rain-runoff processes and phosphorus transport processes in lowland polders is critical in finding reasonable measures to alleviate the eutrophication problem of downstream rivers and lakes. This study develops a lowland Polder Hydrology and Phosphorus modeling System (PHPS) by coupling the WALRUS-paddy model and an improved phosphorus module of a Phosphorus Dynamic model for lowland Polder systems (PDP). It considers some important hydrological characteristics, such as groundwater-unsaturated zone coupling, groundwater-surface water feedback, human-controlled irrigation and discharge, and detailed physical and biochemical cycles of phosphorus in surface water. The application of the model in the Jianwei polder shows that the simulated phosphorus matches well with the measured values. The high precision of this model combined with its low input data requirement and efficient computation make it practical and easy to the water resources management of Chinese polders. Parameter sensitivity analysis demonstrates that K uptake , c Q2 , c W1 , and c Q1 exert a significant effect on the modeled results, whereas K resuspensionMax , K settling , and K mineralization have little effect on the modeled total phosphorus. Among the three types of uncertainties (i.e., parameter, initial condition, and forcing uncertainties), forcing uncertainty produces the strongest effect on the simulated phosphorus. Based on the analysis result of annual phosphorus balance when considering the high import from irrigation and fertilization, lowland polder is capable of retaining phosphorus and reducing phosphorus export to surrounding aquatic ecosystems because of their special hydrological regulation regime. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. An interactive modelling tool for understanding hydrological processes in lowland catchments

    Science.gov (United States)

    Brauer, Claudia; Torfs, Paul; Uijlenhoet, Remko

    2016-04-01

    Recently, we developed the Wageningen Lowland Runoff Simulator (WALRUS), a rainfall-runoff model for catchments with shallow groundwater (Brauer et al., 2014ab). WALRUS explicitly simulates processes which are important in lowland catchments, such as feedbacks between saturated and unsaturated zone and between groundwater and surface water. WALRUS has a simple model structure and few parameters with physical connotations. Some default functions (which can be changed easily for research purposes) are implemented to facilitate application by practitioners and students. The effect of water management on hydrological variables can be simulated explicitly. The model description and applications are published in open access journals (Brauer et al, 2014). The open source code (provided as R package) and manual can be downloaded freely (www.github.com/ClaudiaBrauer/WALRUS). We organised a short course for Dutch water managers and consultants to become acquainted with WALRUS. We are now adapting this course as a stand-alone tutorial suitable for a varied, international audience. In addition, simple models can aid teachers to explain hydrological principles effectively. We used WALRUS to generate examples for simple interactive tools, which we will present at the EGU General Assembly. C.C. Brauer, A.J. Teuling, P.J.J.F. Torfs, R. Uijlenhoet (2014a): The Wageningen Lowland Runoff Simulator (WALRUS): a lumped rainfall-runoff model for catchments with shallow groundwater, Geosci. Model Dev., 7, 2313-2332. C.C. Brauer, P.J.J.F. Torfs, A.J. Teuling, R. Uijlenhoet (2014b): The Wageningen Lowland Runoff Simulator (WALRUS): application to the Hupsel Brook catchment and Cabauw polder, Hydrol. Earth Syst. Sci., 18, 4007-4028.

  16. Removal of congo red and methylene blue from waste water using coagulation

    International Nuclear Information System (INIS)

    Ghaffar, S.; Nosheen, S.; Ahmad, N.

    2011-01-01

    The textile industry has been condemned as being one of the world's worst offenders in terms of pollution Because of increasing population and industrial developments, a huge amount of wastewater is discharged to the environment above the level that the nature can eliminate. Many techniques like oxidation, reduction, physical treatment and biological method are available for removal of colored dyes from wastewater. The work presented here involved the decolorisation of wastewater containing congo red and methylene blue using various coagulants such as alum, bentonite and lime. The effect of various experimental factors such as dosage of coagulants, contact time between coagulant and dye and concentration of dyes and working environment like shaking and static was studied. Under static condition alum give almost 43% removal of congo red while with 10 minutes shaking 74 % removal of 80 dye was achieved with same coagulant. The highest removal of congo red was found to be 99.5 % by using alum after 30 minutes of shaking but in case of methylene blue it intensified the color and gave negative results. Lime gave only 33 % color removal of congo red under static conditions while 57% color was removed under shaking conditions. Maximum color removal achieved by lime was 89% at 40 minutes with shaking condition. Lime gave 60% removal of methylene blue in static condition and 90% removal in shaking condition and maximum absorbance at 80 ppm was 90%. Bentonite also used for the removal of methylene blue and gave 89% removal in shaking condition. By increasing shaking time %age removal increased to 100% at 40 min. And amount of coagulant increased the removal efficiency it attained 100% in both lime and bentonite coagulant for methylene blue Overall alum was found to be better coagulant for the removal of congo red from its aqueous solution. Lime and bentonite both proved better and economical for removal of methylene blue from aqueous solution at lab scale. (author)

  17. The Congo Trap: MONUSCO Islands of Stability in the Sea of Instability

    Directory of Open Access Journals (Sweden)

    Alberto Barrera

    2015-11-01

    Full Text Available 2014 was a hopeful year for the Democratic Republic of Congo (DRC. The M23 movement had been defeated in military operations in which one of the last peacekeeping experiments, the UN Force Intervention Brigade, had played a decisive role. A third UN stabilization plan, the ‘islands of stability’ was proposed to continue the stabilization of a country considered in a post-conflict phase. However, the number of internally displaced persons (IDPs has almost tripled in the country since 2007. This article will argue that DRC is still immersed into an old social conflict that existed before the Congo Wars and the roots of which are not being addressed. It will argue that the United Nations Organization Stabilization Mission in the Democratic Republic of the Congo (MONUSCO and the ‘islands of stability’ strategy can address some of the secondary causes of the Congo conflict, such as its internationalization, the presence in DRC of foreign armed groups or the ‘blood minerals’, but cannot address its primary causes: land struggles, an old cycle of violence and the fragmentation of the Congolese society and political elite that is jeopardizing the restoration of the state authority. The huge dimensions of each of these factors make the Congo conflict ‘one of the most complex and intricate environments ever faced by a peacekeeping mission’, for which MONUSCO’s mandate, resources and stabilization strategy do not seem powerful enough. When the UN organized the 2006 elections legitimized a ‘spoiler state’, the bottleneck of all the reforms needed to stabilize the country. The UN fell thus into a trap and became part of the conflict. Lessons learned should be taken for future UN operations.

  18. [The Prince Léopold Institute for Tropical Medicine in Antwerp: an overview].

    Science.gov (United States)

    Baetens, Roland

    2009-01-01

    The struggle against the sleeping sickness in Congo was the major reason for the opening of a School of Tropical Medicine (1906). The edition of new statutes in 1931 at the moment of the transfer to Antwerp conformed the autonomous and neutral character of the Institute. On the other hand, as the person responsible to the community represented by the Ministery of Colonies and--later--the Ministery of Education, she had to publish an annual report on their activities and finances.After the independence of the colony (1960) the teaching and research policy accentuated development aid, and in particular the fight against tropical disease (malaria, sleeping sickness, leishmaniasis...) and HIV (AIDS and Tuberculosis). The Institute delivers postgraduate and master's degrees. Each year, two hundred doctors and nurses attend its classes, and around a hundred students from over the world prepare for their medical degree. The Institute of Tropical Medicine in Antwerp is a'center of excellence' and an important component in an international network that aims for 'Health for all'.

  19. Evaluating the effect of nutrient redistribution by animals on the phosphorus cycle of lowland Amazonia

    Directory of Open Access Journals (Sweden)

    C. Buendía

    2018-01-01

    Full Text Available Phosphorus (P availability decreases with soil age and potentially limits the productivity of ecosystems growing on old and weathered soils. Despite growing on ancient soils, ecosystems of lowland Amazonia are highly productive and are among the most biodiverse on Earth. P eroded and weathered in the Andes is transported by the rivers and deposited in floodplains of the lowland Amazon basin creating hotspots of P fertility. We hypothesize that animals feeding on vegetation and detritus in these hotspots may redistribute P to P-depleted areas, thus contributing to dissipate the P gradient across the landscape. Using a mathematical model, we show that animal-driven spatial redistribution of P from rivers to land and from seasonally flooded to terra firme (upland ecosystems may sustain the P cycle of Amazonian lowlands. Our results show how P imported to land by terrestrial piscivores in combination with spatial redistribution of herbivores and detritivores can significantly enhance the P content in terra firme ecosystems, thereby highlighting the importance of food webs for the biogeochemical cycling of Amazonia.

  20. The Hindlimb Arterial Vessels in Lowland paca (Cuniculus paca, Linnaeus 1766).

    Science.gov (United States)

    Leal, L M; de Freitas, H M G; Sasahara, T H C; Machado, M R F

    2016-04-01

    This study aims to describe the origin and distribution of the hindlimb arterial vessels. Five adult lowland pacas (Cuniculus paca) were used. Stained and diluted latex was injected, caudally to the aorta. After fixation in 10% paraformaldehyde for 72 h, we dissected to visualize and identify the vessels. It was found out that the vascularization of the hindlimb in lowland paca derives from the terminal branch of the abdominal aorta. The common iliac artery divides into external iliac and internal iliac. The external iliac artery emits the deep iliac circumflex artery, the pudendal epigastric trunk, the deep femoral artery; the femoral artery originates the saphenous artery, it bifurcates into cranial and caudal saphenous arteries. Immediately after the knee joint, the femoral artery is called popliteal artery, which divides into tibial cranial and tibial caudal arteries at the level of the crural inter-osseous space. The origin and distribution of arteries in the hindlimb of lowland paca resembles that in other wild rodents, as well as in the domestic mammals. © 2014 Blackwell Verlag GmbH.

  1. Daytime habitat selection for juvenile parr brown trout (Salmo trutta in small lowland streams

    Directory of Open Access Journals (Sweden)

    Conallin J.

    2014-03-01

    Full Text Available Physical habitat is important in determining the carrying capacity of juvenile brown trout, and within freshwater management. Summer daytime physical habitat selection for the parr lifestage (7–20 cm juvenile brown trout (Salmo trutta was assessed in 6 small lowland streams. Habitat preference was determined for the four variables; water velocity, water depth, substrate and cover, and the preferences for physical habitat selection were expressed in terms of habitat suitability indices (HSI’s. The statistical confidence of HSI’s was evaluated using power analysis. It was found that a minimum of 22 fish observations was needed to have statistical confidence in the HSIs for water depth, and a minimum of 92 fish observations for water velocity during daytime summer conditions. Generally parr were utilising the deeper habitats, indicating preference for deeper water. Cover was also being selected for at all sites, but selection was inconsistent among sites for the variables substrate and velocity. The results indicate that during daytime summer conditions water depth is a significant variable for parr habitat selection in these small lowland streams, with cover also being important. Therefore, daytime refugia may be a critical limiting factor for parr in small lowland streams, and important for stream management actions under the Water Framework Directive.

  2. Survival and growth rates of juvenile salmonids reared in lowland streams

    Directory of Open Access Journals (Sweden)

    Golski Janusz

    2016-12-01

    Full Text Available The aim of this study was to assess the efficiency of propagating juvenile trout, Salmo trutta L. in small lowland streams and to evaluate the impact of the environmental conditions in the streams on the juvenile fish. Brown trout (Salmo trutta fario and sea trout (Salmo trutta trutta early fry fed under controlled conditions were used to stock third-order lowland streams. During summer, fall, and spring catches, fry were counted, measured, and weighed. The following parameters were calculated using the data collected: fry stocking density (ind. m-2; survival; specific mortality rate (SMR; length range; mean specimen length; body weight; mean body weight; specific growth rate (SGR; body condition (Fulton’s index. The ichthyological studies were accompanied by simultaneous analyses of environmental conditions that were performed monthly, and benthic macroinvertebrates were sampled in spring and fall. No differences were observed in the biological parameters analyzed between sea trout and brown trout. Variability in environmental parameters such as temperature, oxygenation, conductivity, and stream width and depth were associated with differentiation in the biological parameters of the fry. The results clearly indicate that the considerable potential of small lowland streams for the propagation of salmonid juvenile stages is currently underexploited.

  3. Maximal exercise and muscle oxygen extraction in acclimatizing lowlanders and high altitude natives

    DEFF Research Database (Denmark)

    Lundby, Carsten; Sander, Mikael; van Hall, Gerrit

    2006-01-01

    , and is the focus of the present study. We have studied six lowlanders during maximal exercise at sea level (SL) and with acute (AH) exposure to 4,100 m altitude, and again after 2 (W2) and 8 weeks (W8) of altitude sojourn, where also eight high altitude native (Nat) Aymaras were studied. Fractional arterial muscle...... O(2) extraction at maximal exercise was 90.0+/-1.0% in the Danish lowlanders at sea level, and remained close to this value in all situations. In contrast to this, fractional arterial O(2) extraction was 83.2+/-2.8% in the high altitude natives, and did not change with the induction of normoxia....... The capillary oxygen conductance of the lower extremity, a measure of oxygen diffusing capacity, was decreased in the Danish lowlanders after 8 weeks of acclimatization, but was still higher than the value obtained from the high altitude natives. The values were (in ml min(-1) mmHg(-1)) 55.2+/-3.7 (SL), 48...

  4. Stimulate The Growth of Rice Using Endophytic Bacteria from Lowland Rice Plant Tissue

    Directory of Open Access Journals (Sweden)

    Nuni Gofar

    2015-07-01

    Full Text Available Exploration and selection of endophytic bacteria from healthy food crops grown in lowland ecosystem is important to be conducted in order to get growth-stimulating endophytic bacteria at soil with low fertility level so that capable to optimize initial growth of food crops and subsequently can increase productivity level of lowland soil.The research objective was to isolate and to test the IAA-producing endophytic bacteria isolate in stimulating the rice crop growth at lowland area. Endophytic bacteria are isolated from tissues of rice, corn and peanut crops which grown at shallow swamp land in Ogan Ilir and Ogan Komering Ilir Districts, South Sumatra, Indonesia. There was nine isolates of nitrogen-fixer endophytic bacteria that capable to contribute IAA phytohormone into their growth media. The P31 isolate from rice crop tisssue of 2 months old produce the best rice sprouts than other isolates. This isolate can contribute of about 10 mg kg-1 IAA to its growth medium and increase the crowns dry weight and the roots dry weight respectively with magnitudes of 133% and 225% compared to control treatment. Concentration and absorbtion of N for rice crops innoculated with P31 isolates had increased by 169% and 400%, recpectively. The P31 isolates had been identified as Burkholderia pseudomallei (also known as Pseudomonas pseudomallei.

  5. Impacts of Climate Change on the Collapse of Lowland Maya Civilization

    Science.gov (United States)

    Douglas, Peter M. J.; Demarest, Arthur A.; Brenner, Mark; Canuto, Marcello A.

    2016-06-01

    Paleoclimatologists have discovered abundant evidence that droughts coincided with collapse of the Lowland Classic Maya civilization, and some argue that climate change contributed to societal disintegration. Many archaeologists, however, maintain that drought cannot explain the timing or complex nature of societal changes at the end of the Classic Period, between the eighth and eleventh centuries ce. This review presents a compilation of climate proxy data indicating that droughts in the ninth to eleventh century were the most severe and frequent in Maya prehistory. Comparison with recent archaeological evidence, however, indicates an earlier beginning for complex economic and political processes that led to the disintegration of states in the southern region of the Maya lowlands that precedes major droughts. Nonetheless, drought clearly contributed to the unusual severity of the Classic Maya collapse, and helped to inhibit the type of recovery seen in earlier periods of Maya prehistory. In the drier northern Maya Lowlands, a later political collapse at ca. 1000 ce appears to be related to ongoing extreme drought. Future interdisciplinary research should use more refined climatological and archaeological data to examine the relationship between climate and social processes throughout the entirety of Maya prehistory.

  6. Cerebral pressure-flow relationship in lowlanders and natives at high altitude.

    Science.gov (United States)

    Smirl, Jonathan D; Lucas, Samuel J E; Lewis, Nia C S; duManoir, Gregory R; Dumanior, Gregory R; Smith, Kurt J; Bakker, Akke; Basnyat, Aperna S; Ainslie, Philip N

    2014-02-01

    We investigated if dynamic cerebral pressure-flow relationships in lowlanders are altered at high altitude (HA), differ in HA natives and after return to sea level (SL). Lowlanders were tested at SL (n=16), arrival to 5,050 m, after 2-week acclimatization (with and without end-tidal PO2 normalization), and upon SL return. High-altitude natives (n=16) were tested at 5,050 m. Testing sessions involved resting spontaneous and driven (squat-stand maneuvers at very low (VLF, 0.05 Hz) and low (LF, 0.10 Hz) frequencies) measures to maximize blood pressure (BP) variability and improve assessment of the pressure-flow relationship using transfer function analysis (TFA). Blood flow velocity was assessed in the middle (MCAv) and posterior (PCAv) cerebral arteries. Spontaneous VLF and LF phases were reduced and coherence was elevated with acclimatization to HA (Pflow coupling. However, when BP was driven, both the frequency- and time-domain metrics were unaltered and comparable with HA natives. Acute mountain sickness was unrelated to TFA metrics. In conclusion, the driven cerebral pressure-flow relationship (in both frequency and time domains) is unaltered at 5,050 m in lowlanders and HA natives. Our findings indicate that spontaneous changes in TFA metrics do not necessarily reflect physiologically important alterations in the capacity of the brain to regulate BP.

  7. Evaluating the effect of nutrient redistribution by animals on the phosphorus cycle of lowland Amazonia

    Science.gov (United States)

    Buendía, Corina; Kleidon, Axel; Manzoni, Stefano; Reu, Björn; Porporato, Amilcare

    2018-01-01

    Phosphorus (P) availability decreases with soil age and potentially limits the productivity of ecosystems growing on old and weathered soils. Despite growing on ancient soils, ecosystems of lowland Amazonia are highly productive and are among the most biodiverse on Earth. P eroded and weathered in the Andes is transported by the rivers and deposited in floodplains of the lowland Amazon basin creating hotspots of P fertility. We hypothesize that animals feeding on vegetation and detritus in these hotspots may redistribute P to P-depleted areas, thus contributing to dissipate the P gradient across the landscape. Using a mathematical model, we show that animal-driven spatial redistribution of P from rivers to land and from seasonally flooded to terra firme (upland) ecosystems may sustain the P cycle of Amazonian lowlands. Our results show how P imported to land by terrestrial piscivores in combination with spatial redistribution of herbivores and detritivores can significantly enhance the P content in terra firme ecosystems, thereby highlighting the importance of food webs for the biogeochemical cycling of Amazonia.

  8. Lowland-upland migration of sauropod dinosaurs during the Late Jurassic epoch.

    Science.gov (United States)

    Fricke, Henry C; Hencecroth, Justin; Hoerner, Marie E

    2011-10-26

    Sauropod dinosaurs were the largest vertebrates ever to walk the Earth, and as mega-herbivores they were important parts of terrestrial ecosystems. In the Late Jurassic-aged Morrison depositional basin of western North America, these animals occupied lowland river-floodplain settings characterized by a seasonally dry climate. Massive herbivores with high nutritional and water needs could periodically experience nutritional and water stress under these conditions, and thus the common occurrence of sauropods in this basin has remained a paradox. Energetic arguments and mammalian analogues have been used to suggest that migration allowed sauropods access to food and water resources over a wide region or during times of drought or both, but there has been no direct support for these hypotheses. Here we compare oxygen isotope ratios (δ(18)O) of tooth-enamel carbonate from the sauropod Camarasaurus with those of ancient soil, lake and wetland (that is, 'authigenic') carbonates that formed in lowland settings. We demonstrate that certain populations of these animals did in fact undertake seasonal migrations of several hundred kilometres from lowland to upland environments. This ability to describe patterns of sauropod movement will help to elucidate the role that migration played in the ecology and evolution of gigantism of these and associated dinosaurs.

  9. An investigation of tropical Atlantic bias in a high-resolution coupled regional climate model

    Energy Technology Data Exchange (ETDEWEB)

    Patricola, Christina M.; Saravanan, R.; Hsieh, Jen-Shan [Texas A and M University, Department of Atmospheric Sciences, College Station, TX (United States); Li, Mingkui; Xu, Zhao [Texas A and M University, Department of Oceanography, College Station, TX (United States); Ocean University of China, Key Laboratory of Physical Oceanography of Ministry of Education, Qingdao (China); Chang, Ping [Texas A and M University, Department of Oceanography, College Station, TX (United States); Ocean University of China, Key Laboratory of Physical Oceanography of Ministry of Education, Qingdao (China); Second Institute of Oceanography, State Key Laboratory of Satellite Ocean Environment Dynamics, Hangzhou, Zhejiang (China)

    2012-11-15

    Coupled atmosphere-ocean general circulation models (AOGCMs) commonly fail to simulate the eastern equatorial Atlantic boreal summer cold tongue and produce a westerly equatorial trade wind bias. This tropical Atlantic bias problem is investigated with a high-resolution (27-km atmosphere represented by the Weather Research and Forecasting Model, 9-km ocean represented by the Regional Ocean Modeling System) coupled regional climate model. Uncoupled atmospheric simulations test climate sensitivity to cumulus, land-surface, planetary boundary layer, microphysics, and radiation parameterizations and reveal that the radiation scheme has a pronounced impact in the tropical Atlantic. The CAM radiation simulates a dry precipitation (up to -90%) and cold land-surface temperature (up to -8 K) bias over the Amazon related to an over-representation of low-level clouds and almost basin-wide westerly trade wind bias. The Rapid Radiative Transfer Model and Goddard radiation simulates doubled Amazon and Congo Basin precipitation rates and a weak eastern Atlantic trade wind bias. Season-long high-resolution coupled regional model experiments indicate that the initiation of the warm eastern equatorial Atlantic sea surface temperature (SST) bias is more sensitive to the local rather than basin-wide trade wind bias and to a wet Congo Basin instead of dry Amazon - which differs from AOGCM simulations. Comparisons between coupled and uncoupled simulations suggest a regional Bjerknes feedback confined to the eastern equatorial Atlantic amplifies the initial SST, wind, and deepened thermocline bias, while barrier layer feedbacks are relatively unimportant. The SST bias in some CRCM simulations resembles the typical AOGCM bias indicating that increasing resolution is unlikely a simple solution to this problem. (orig.)

  10. Habitats and landscapes associated with bird species in a lowland conifer-dominated ecosystem

    Directory of Open Access Journals (Sweden)

    Edmund J. Zlonis

    2017-06-01

    Full Text Available Human-induced effects on lowland conifer forests in hemiboreal regions are increasing because of expanded use of these northern ecosystems for raw materials, energy, and minerals as well as the potential effects of climatic changes. These forests support many breeding bird species across the Holarctic and allow the persistence of several boreal bird species in hemiboreal and even temperate regions. These bird species are of particular conservation concern as shifting patterns northward in forest composition caused by climate change will likely affect their populations. However, effective management and conservation options are limited because the specifics of these species' breeding habitats are not well understood. We modeled and mapped habitat suitability for 11 species of boreal birds that breed in the lowland conifer forests of the Agassiz Lowlands Ecological Subsection in northern Minnesota and are likely to have reduced breeding habitat in the future: Spruce Grouse (Falcipennis canadensis, Black-backed Woodpecker (Picoides arcticus, Olive-sided Flycatcher (Contopus cooperi, Yellow-bellied Flycatcher (Empidonax flaviventris, Boreal Chickadee (Poecile hudsonicus, Golden-crowned Kinglet (Regulus satrapa, Ruby-crowned Kinglet (Regulus calendula, Swainson's Thrush (Catharus ustulatus, Connecticut Warbler (Oporornis agilis, Palm Warbler (Setophaga palmarum, and Dark-eyed Junco (Junco hyemalis. Sets of 7 to 16 potential environmental covariates, including both stand-level and landscape attributes, were used to develop individual species models. Within this lowland conifer-dominated ecosystem, we found significant selection for specific forest and landscape characteristics by all but one of these species, with the best models including between one and nine variables. Habitat suitability maps were developed from these models and predictions tested with an independent dataset. Model performance depended on species, correctly predicting 56-96% of

  11. Tannins in tropical woods

    Energy Technology Data Exchange (ETDEWEB)

    Doat, J

    1978-01-01

    A preliminary study was made of the chemistry of pyrogallol- and catecholtannins, their general properties and methods of extraction and determination. Three methods of estimation - Lowenthal, powdered hide and spectrophotometry - were compared using two control solutions, four samples of wood and one of bark. Using the empirical powdered hide method, tannins of both types were estimated in wood and bark of various tropical species (some separately and some as a mixture), Moroccan oaks (Quercus suber and Q. ilex), and European oak 9Q. petraea). Further tests were made on the wood and bark of the two mangrove species, Rhizophora mangle and R. racemosa, by subjecting them to successive extraction with a range of solvents. None of the woods tested had as much as the 10% of tannins considered necessary in economic sources. The bark of the two mangroves, of Eucalyptus urophylla and of Prosopis africana had tannin contents over 10% and the latter two species had very favorable tannin/non-tannin ratios. All the tropical species, with the probable exception of E. urophylla, had only catecholtannins. Only the oaks and E. urophylla bark gave positive results when tested for gallotannins.

  12. Tropical Cyclone Information System

    Science.gov (United States)

    Li, P. Peggy; Knosp, Brian W.; Vu, Quoc A.; Yi, Chao; Hristova-Veleva, Svetla M.

    2009-01-01

    The JPL Tropical Cyclone Infor ma tion System (TCIS) is a Web portal (http://tropicalcyclone.jpl.nasa.gov) that provides researchers with an extensive set of observed hurricane parameters together with large-scale and convection resolving model outputs. It provides a comprehensive set of high-resolution satellite (see figure), airborne, and in-situ observations in both image and data formats. Large-scale datasets depict the surrounding environmental parameters such as SST (Sea Surface Temperature) and aerosol loading. Model outputs and analysis tools are provided to evaluate model performance and compare observations from different platforms. The system pertains to the thermodynamic and microphysical structure of the storm, the air-sea interaction processes, and the larger-scale environment as depicted by ocean heat content and the aerosol loading of the environment. Currently, the TCIS is populated with satellite observations of all tropical cyclones observed globally during 2005. There is a plan to extend the database both forward in time till present as well as backward to 1998. The portal is powered by a MySQL database and an Apache/Tomcat Web server on a Linux system. The interactive graphic user interface is provided by Google Map.

  13. Tropical Rainforest Education. ERIC Digest.

    Science.gov (United States)

    Rillero, Peter

    This digest provides four guideposts for tropical rainforest education: (1) structure; (2) location and climate; (3) importance; and (4) conservation of resources. Research is cited and background information provided about the layers of life and the adaptations of life within the tropical rain forest. Aspects of life within and near rain forests…

  14. Mycorrhizas and tropical soil fertility

    NARCIS (Netherlands)

    Cardoso, I.M.; Kuyper, T.W.

    2006-01-01

    Major factors that constrain tropical soil fertility and sustainable agriculture are low nutrient capital, moisture stress, erosion, high P fixation, high acidity with aluminium toxicity, and low soil biodiversity. The fragility of many tropical soils limits food production in annual cropping

  15. The impact of rise of the Andes and Amazon landscape evolution on diversification of lowland terra-firme forest birds

    Science.gov (United States)

    Aleixo, A.; Wilkinson, M. J.

    2011-12-01

    Since the 19th Century, the unmatched biological diversity of Amazonia has stimulated a diverse set of hypotheses accounting for patterns of species diversity and distribution in mega-diverse tropical environments. Unfortunately, the evidence supporting particular hypotheses to date is at best described as ambiguous, and no generalizations have emerged yet, mostly due to the lack of comprehensive comparative phylogeographic studies with thorough trans-Amazonian sampling of lineages. Here we report on spatial and temporal patterns of diversification estimated from mitochondrial gene trees for 31 lineages of birds associated with upland terra-firme forest, the dominant habitat in modern lowland Amazonia. The results confirm the pervasive role of Amazonian rivers as primary barriers separating sister lineages of birds, and a protracted spatio-temporal pattern of diversification, with a gradual reduction of earlier (1st and 2nd) and older (> 2 mya) splits associated with each lineage in an eastward direction (the easternmost tributaries of the Amazon, the Xingu and Tocantins Rivers, are not associated with any splits older than > 2 mya). This "younging-eastward" pattern may have an abiotic explanation related to landscape evolution. Triggered by a new pulse of Andean uplift, it has been proposed that modern Amazon basin landscapes may have evolved successively eastward, away from the mountain chain, starting ~10 mya. This process was likely based on the deposition of vast fluvial sediment masses, known as megafans, which apparently extended in series progressively eastward from Andean sources. The effects on drainage patterns are apparent from the location of axial rivers such as the Negro / Orinoco and Madeira which lie at the distal ends of major megafan ramparts at cratonic margins furthest from the Andes. Megafan extension plausibly explains the progressive extinction of the original Pebas wetland of west-central Amazonia by the present fluvial landsurfaces where

  16. Temperate radiations and dying embers of a tropical past: the diversification of Viburnum.

    Science.gov (United States)

    Spriggs, Elizabeth L; Clement, Wendy L; Sweeney, Patrick W; Madriñán, Santiago; Edwards, Erika J; Donoghue, Michael J

    2015-07-01

    We used a near-complete phylogeny for the angiosperm clade Viburnum to assess lineage diversification rates, and to examine possible morphological and ecological factors driving radiations. Maximum-likelihood and Bayesian approaches identified shifts in diversification rate and possible links to character evolution. We inferred the ancestral environment for Viburnum and changes in diversification dynamics associated with subsequent biome shifts. Viburnum probably diversified in tropical forests of Southeast Asia in the Eocene, with three subsequent radiations in temperate clades during the Miocene. Four traits (purple fruits, extrafloral nectaries, bud scales and toothed leaves) were statistically associated with higher rates of diversification. However, we argue that these traits are unlikely to be driving diversification directly. Instead, two radiations were associated with the occupation of mountainous regions and a third with repeated shifts between colder and warmer temperate forests. Early-branching depauperate lineages imply that the rare lowland tropical species are 'dying embers' of once more diverse lineages; net diversification rates in Viburnum likely decreased in these tropical environments after the Oligocene. We suggest that 'taxon pulse' dynamics might characterize other temperate plant lineages. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  17. Five thousand years of tropical lake sediment DNA records from Benin

    Science.gov (United States)

    Bremond, L.; Favier, C.; Ficetola, G. F.; Tossou, M. G.; Akouégninou, A.; Gielly, L.; Giguet-Covex, C.; Oslisly, R.; Salzmann, U.

    2017-08-01

    Until now, sedimentary DNA (sedDNA) studies have only focused on cold and temperate regions were DNA is relatively well preserved. Consequently, the tropics, where vegetation is hyperdiverse and natural archives are rare, have been neglected and deserve attention. In this study, we used next-generation sequencing to barcode sedDNA from Lake Sele, localized in the tropical lowlands of Benin (Africa), and compared the taxonomic diversity detected by DNA analyses with pollen assemblages. Plant sedDNA was successfully amplified from 33 of the 34 successfully extracted samples. In total, 43 taxa were identified along the 5000 years spanned by the sediment: 22 taxa were identified at the family level and 21 at the genus level. The plant diversity recovered through sedDNA from Lake Sele showed a specific local signal and limited overlapping with pollen. Introduced plants, grown and cultivated close to the water, such as sweet potato, were also well recorded by sedDNA. It appears, therefore, to be a promising approach to studying past diversity in tropical regions, and could help in tracking the introduction and history of agriculture. This is the first time this method has been used in the field of domestication and dissemination of several specific crops, and the results are very encouraging.

  18. Amplification of wildfire area burnt by hydrological drought in the humid tropics

    Science.gov (United States)

    Taufik, Muh; Torfs, Paul J. J. F.; Uijlenhoet, Remko; Jones, Philip D.; Murdiyarso, Daniel; van Lanen, Henny A. J.

    2017-06-01

    Borneo's diverse ecosystems, which are typical humid tropical conditions, are deteriorating rapidly, as the area is experiencing recurrent large-scale wildfires, affecting atmospheric composition and influencing regional climate processes. Studies suggest that climate-driven drought regulates wildfires, but these overlook subsurface processes leading to hydrological drought, an important driver. Here, we show that models which include hydrological processes better predict area burnt than those solely based on climate data. We report that the Borneo landscape has experienced a substantial hydrological drying trend since the early twentieth century, leading to progressive tree mortality, more severe than in other tropical regions. This has caused massive wildfires in lowland Borneo during the past two decades, which we show are clustered in years with large areas of hydrological drought coinciding with strong El Niño events. Statistical modelling evidence shows amplifying wildfires and greater area burnt in response to El Niño/Southern Oscillation (ENSO) strength, when hydrology is considered. These results highlight the importance of considering hydrological drought for wildfire prediction, and we recommend that hydrology should be considered in future studies of the impact of projected ENSO strength, including effects on tropical ecosystems, and biodiversity conservation.

  19. Lowland tapir (Tapirus terrestris) distribution, activity patterns and relative abundance in the Greater Madidi-Tambopata Landscape.

    Science.gov (United States)

    Wallace, Robert; Ayala, Guido; Viscarra, Maria

    2012-12-01

    Lowland tapir distribution is described in northwestern Bolivia and southeastern Peru within the Greater Madidi-Tambopata Landscape, a priority Tapir Conservation Unit, using 1255 distribution points derived from camera trapping efforts, field research and interviews with park guards from 5 national protected areas and hunters from 19 local communities. A total of 392 independent camera trapping events from 14 camera trap surveys at 11 sites demonstrated the nocturnal and crepuscular activity patterns (86%) of the lowland tapir and provide 3 indices of relative abundance for spatial and temporal comparison. Capture rates for lowland tapirs were not significantly different between camera trapping stations placed on river beaches versus those placed in the forest. Lowland tapir capture rates were significantly higher in the national protected areas of the region versus indigenous territories and unprotected portions of the landscape. Capture rates through time suggested that lowland tapir populations are recovering within the Tuichi Valley, an area currently dedicated towards ecotourism activities, following the creation (1995) and subsequent implementation (1997) of the Madidi National Park in Bolivia. Based on our distributional data and published conservative estimates of population density, we calculated that this transboundary landscape holds an overall lowland tapir population of between 14 540 and 36 351 individuals, of which at least 24.3% are under protection from national and municipal parks. As such, the Greater Madidi-Tambopata Landscape should be considered a lowland tapir population stronghold and priority conservation efforts are discussed in order to maintain this population. © 2012 Wiley Publishing Asia Pty Ltd, ISZS and IOZ/CAS.

  20. Three-dimensional geometric morphometric analysis of talar morphology in extant gorilla taxa from highland and lowland habitats.

    Science.gov (United States)

    Knigge, Ryan P; Tocheri, Matthew W; Orr, Caley M; Mcnulty, Kieran P

    2015-01-01

    Western gorillas (Gorilla gorilla) are known to climb significantly more often than eastern gorillas (Gorilla beringei), a behavioral distinction attributable to major differences in their respective habitats (i.e., highland vs. lowland). Genetic evidence suggests that the lineages leading to these taxa began diverging from one another between approximately 1 and 3 million years ago. Thus, gorillas offer a special opportunity to examine the degree to which morphology of recently diverged taxa may be "fine-tuned" to differing ecological requirements. Using three-dimensional (3D) geometric morphometrics, we compared talar morphology in a sample of 87 specimens including western (lowland), mountain (highland), and grauer gorillas (lowland and highland populations). Talar shape was captured with a series of landmarks and semilandmarks superimposed by generalized Procrustes analysis. A between-group principal components analysis of overall talar shape separates gorillas by ecological habitat and by taxon. An analysis of only the trochlea and lateral malleolar facet identifies subtle variations in trochlear shape between western lowland and lowland grauer gorillas, potentially indicative of convergent evolution of arboreal adaptations in the talus. Lastly, talar shape scales differently with centroid size for highland and lowland gorillas, suggesting that ankle morphology may track body-size mediated variation in arboreal behaviors differently depending on ecological setting. Several of the observed shape differences are linked biomechanically to the facilitation of climbing in lowland gorillas and to stability and load-bearing on terrestrial substrates in the highland taxa, providing an important comparative model for studying morphological variation in groups known only from fossils (e.g., early hominins). © 2014 Wiley Periodicals, Inc.