WorldWideScience

Sample records for species lacking population

  1. Population genetics and cryptic species

    International Nuclear Information System (INIS)

    McPheron, Bruce A.

    2000-01-01

    Does the definition of a species matter for pest management purposes? Taxonomists provide us with tools - usually morphological characters - to identify a group of organisms that we call a species. The implication of this identification is that all of the individuals that fit the provided description are members of the species in question. The taxonomists have considered the range of variation among individuals in defining the species, but this variation is often forgotten when we take the concept of species to the level of management. Just as there is morphological variation among individuals, there is also variation in practically any character we might imagine, which has implications for the short and long term success of our management tactics. The rich literature on insecticide resistance should be a constant reminder of the fact that the pressure on pest survival and reproduction applied by our management approaches frequently leads to evolutionary changes within the pest species. The degree of variation within a particular species is a defining characteristic of that species. This level of variability may have very important implications for successful management, so it is very important to measure variation and, whenever possible, the genetic basis of that variation, in a target species. Population genetic approaches can provide evidence of genetic structure (or lack thereof) among populations of a species. These types of data can be used to discuss the movement of pest populations on a local or global scale. In other cases, we may have a complex of species that share some, but not all, characteristics. Species complexes that share morphological characters (i.e., cannot be easily distinguished) but not biological characters are referred to as sibling or cryptic species

  2. LACK OF AWARENESS ABOUT SAFE BLOOD IN PAKISTANI POPULATION

    Directory of Open Access Journals (Sweden)

    Muhammad Usman

    2014-12-01

    Full Text Available Blood transfusion is a life saving procedure in various transfusion-dependent life threatening conditions and donation of safe blood is a prerequisite for achieving this goal. This study was designed to evaluate the awareness regarding “safe blood” in Pakistani population. This study was conducted at a large scale through a population survey. The test population was divided into two groups i.e. general population and students. The Performa was designed for a general and student population and included 20 questions related to awareness of safe blood. A total of 4900 individuals belonging to different ethnic groups were included in this population survey. Results of social survey were analyzed by using Usman and Moin awareness chart. Results of this study revealed profound unawareness about safe blood in Pakistani population. This study found lack of awareness about safe blood as a major factor that is playing a vital role in the propagation of blood borne diseases in Pakistan. To secure the recipients from blood borne complications through blood donation, it is necessary to create effective awareness about safe blood in Pakistani population.

  3. Population dynamics model for plasmid bearing and plasmid lacking ...

    African Journals Online (AJOL)

    Streptokinase production in bioreactor is well associated to cell population dynamics. It is an established fact that two types of cell populations are found to emerge from the initial pool of recombinant cell population. This phenomenon leads to an undesired loss in yield of the product. Primary metabolites, like acetic acid etc ...

  4. Population Genomics of Paramecium Species.

    Science.gov (United States)

    Johri, Parul; Krenek, Sascha; Marinov, Georgi K; Doak, Thomas G; Berendonk, Thomas U; Lynch, Michael

    2017-05-01

    Population-genomic analyses are essential to understanding factors shaping genomic variation and lineage-specific sequence constraints. The dearth of such analyses for unicellular eukaryotes prompted us to assess genomic variation in Paramecium, one of the most well-studied ciliate genera. The Paramecium aurelia complex consists of ∼15 morphologically indistinguishable species that diverged subsequent to two rounds of whole-genome duplications (WGDs, as long as 320 MYA) and possess extremely streamlined genomes. We examine patterns of both nuclear and mitochondrial polymorphism, by sequencing whole genomes of 10-13 worldwide isolates of each of three species belonging to the P. aurelia complex: P. tetraurelia, P. biaurelia, P. sexaurelia, as well as two outgroup species that do not share the WGDs: P. caudatum and P. multimicronucleatum. An apparent absence of global geographic population structure suggests continuous or recent dispersal of Paramecium over long distances. Intergenic regions are highly constrained relative to coding sequences, especially in P. caudatum and P. multimicronucleatum that have shorter intergenic distances. Sequence diversity and divergence are reduced up to ∼100-150 bp both upstream and downstream of genes, suggesting strong constraints imposed by the presence of densely packed regulatory modules. In addition, comparison of sequence variation at non-synonymous and synonymous sites suggests similar recent selective pressures on paralogs within and orthologs across the deeply diverging species. This study presents the first genome-wide population-genomic analysis in ciliates and provides a valuable resource for future studies in evolutionary and functional genetics in Paramecium. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Estimating Effects of Species Interactions on Populations of Endangered Species.

    Science.gov (United States)

    Roth, Tobias; Bühler, Christoph; Amrhein, Valentin

    2016-04-01

    Global change causes community composition to change considerably through time, with ever-new combinations of interacting species. To study the consequences of newly established species interactions, one available source of data could be observational surveys from biodiversity monitoring. However, approaches using observational data would need to account for niche differences between species and for imperfect detection of individuals. To estimate population sizes of interacting species, we extended N-mixture models that were developed to estimate true population sizes in single species. Simulations revealed that our model is able to disentangle direct effects of dominant on subordinate species from indirect effects of dominant species on detection probability of subordinate species. For illustration, we applied our model to data from a Swiss amphibian monitoring program and showed that sizes of expanding water frog populations were negatively related to population sizes of endangered yellow-bellied toads and common midwife toads and partly of natterjack toads. Unlike other studies that analyzed presence and absence of species, our model suggests that the spread of water frogs in Central Europe is one of the reasons for the decline of endangered toad species. Thus, studying population impacts of dominant species on population sizes of endangered species using data from biodiversity monitoring programs should help to inform conservation policy and to decide whether competing species should be subject to population management.

  6. A rapid high-resolution melting method for differentiation of Leishmania species targeting lack gene.

    Science.gov (United States)

    Kuang, Ziwei; Zhang, Chunying; Pang, Huasheng; Ma, Ying

    2018-02-01

    The aim of this research is to verify that if lack gene can be used for differentiation of Leishmania under HRM assay. Two specific primers were designed targeting polymorphic sites on the lack gene sequence. DNA from promastigotes of six species of Leishmania based on reference strains were tested following a HRM protocol. We also tested ten Chinese isolates in blind to validate our method. Combined with amplicon of the two primers, the six reference strains can be easily discriminated without the effect of initial concentration of DNA templates. Ten Chinese isolates detected by our HRM method resulted in full accord with the standard identification results in previous study. HRM is a rapid and reproducible method to discriminate different Leishmania species and lack gene is a potential novel biological characteristic for easy differentiation of Leishmania isolates in China. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Escherichia coli lacking RpoS are rare in natural populations of non-pathogens.

    Science.gov (United States)

    Snyder, Emily; Gordon, David M; Stoebel, Daniel M

    2012-11-01

    The alternative sigma factor RpoS controls a large regulon that allows E. coli to respond to a variety of stresses. Mutations in rpoS can increase rates of nutrient acquisition at the cost of a decrease in stress resistance. These kinds of mutations evolve rapidly under certain laboratory conditions where nutrient acquisition is especially challenging. The frequency of strains lacking RpoS in natural populations of E. coli is less clear. Such strains have been found at frequencies over 20% in some collections of wild isolates. However, laboratory handling can select for RpoS-null strains and may have affected some of these strain collections. Other studies have included an unknown diversity of strains or only used a phenotypic proxy as a measure of RpoS levels. We directly measured RpoS levels in a collection of E. coli that includes the full diversity of the species and that was handled in a manner to minimize the potential for laboratory evolution. We found that only 2% of strains produce no functional RpoS. Comparison of these strains in multiple labs shows that these rpoS mutations occurred in the laboratory. Earlier studies reporting much higher levels of RpoS polymorphism may reflect the storage history of the strains in laboratories rather than true frequency of such strains in natural populations.

  8. A Trunk Support System to Identify Posture Control Mechanisms in Populations Lacking Independent Sitting.

    Science.gov (United States)

    Goodworth, Adam D; Wu, Yen-Hsun; Felmlee, Duffy; Dunklebarger, Ellis; Saavedra, Sandra

    2017-01-01

    Populations with moderate-to-severe motor control impairments often exhibit degraded trunk control and/or lack the ability to sit unassisted. These populations need more research, yet their underdeveloped trunk control complicates identification of neural mechanisms behind their movements. The purpose of this study was to overcome this barrier by developing the first multi-articulated trunk support system to identify visual, vestibular, and proprioception contributions to posture in populations lacking independent sitting. The system provided external stability at a user-specific level on the trunk, so that body segments above the level of support required active posture control. The system included a tilting surface (controlled via servomotor) as a stimulus to investigate sensory contributions to postural responses. Frequency response and coherence functions between the surface tilt and trunk support were used to characterize system dynamics and indicated that surface tilts were accurately transmitted up to 5 Hz. Feasibility of collecting kinematic data in participants lacking independent sitting was demonstrated in two populations: two typically developing infants, [Formula: see text] months, in a longitudinal study (eight sessions each) and four children with moderate-to-severe cerebral palsy (GMFCS III-V). Adaptability in the system was assessed by testing 16 adults (ages 18-63). Kinematic responses to continuous pseudorandom surface tilts were evaluated across 0.046-2 Hz and qualitative feedback indicated that the trunk support and stimulus were comfortable for all subjects. Concepts underlying the system enable both research for, and rehabilitation in, populations lacking independent sitting.

  9. POPULATION DYNAMICS OF PSEUDO-NITZSCHIA SPECIES ...

    African Journals Online (AJOL)

    nb

    ABSTRACT. The genus Pseudo-nitzschia is a chain-forming diatom comprising about 30 species some of which are known to produce domoic acid (DA) that causes amnesic shellfish poisoning (ASP). The current study aimed at assessing the population dynamics of Pseudo-nitzschia in the near shore waters of Dar es ...

  10. Population dynamics of Pseudo-nitzschia species ...

    African Journals Online (AJOL)

    The genus Pseudo-nitzschia is a chain-forming diatom comprising about 30 species some of which are known to produce domoic acid (DA) that causes amnesic shellfish poisoning (ASP). The current study aimed at assessing the population dynamics of Pseudo-nitzschia in the near shore waters of Dar es Salaam. Samples ...

  11. Estimation of the Number of Microbial Species Comprising a Population

    National Research Council Canada - National Science Library

    Slattery, Melanie R

    2008-01-01

    ... comprising a population. This research consisted of creating diverse populations, with a known number of species, and applying the aforementioned methods to samples drawn from the constructed populations...

  12. Lack of access and continuity of adult health care: a national population-based survey

    OpenAIRE

    Dilélio,Alitéia Santiago; Tomasi,Elaine; Thumé,Elaine; Silveira,Denise Silva da; Siqueira,Fernando Carlos Vinholes; Piccini,Roberto Xavier; Silva,Suele Manjourany; Nunes,Bruno Pereira; Facchini,Luiz Augusto

    2015-01-01

    OBJECTIVE To describe the lack of access and continuity of health care in adults. METHODS A cross-sectional population-based study was performed on a sample of 12,402 adults aged 20 to 59 years in urban areas of 100 municipalities of 23 states in the five Brazilian geopolitical regions. Barriers to the access and continuity of health care and were investigated based on receiving, needing and seeking health care (hospitalization and accident/emergency care in the last 12 months; care provided ...

  13. Lack of access and continuity of adult health care: a national population-based survey

    OpenAIRE

    Dilélio, Alitéia Santiago; Tomasi, Elaine; Thumé, Elaine; Silveira, Denise Silva da; Siqueira, Fernando Carlos Vinholes; Piccini, Roberto Xavier; Silva, Suele Manjourany; Nunes, Bruno Pereira; Facchini, Luiz Augusto

    2015-01-01

    OBJECTIVE To describe the lack of access and continuity of health care in adults.METHODS A cross-sectional population-based study was performed on a sample of 12,402 adults aged 20 to 59 years in urban areas of 100 municipalities of 23 states in the five Brazilian geopolitical regions. Barriers to the access and continuity of health care and were investigated based on receiving, needing and seeking health care (hospitalization and accident/emergency care in the last 12 months; care provided b...

  14. Lack of Population Genetic Structuring in Ocelots (Leopardus pardalis in a Fragmented Landscape

    Directory of Open Access Journals (Sweden)

    Marina G. Figueiredo

    2015-07-01

    Full Text Available Habitat fragmentation can promote patches of small and isolated populations, gene flow disruption between those populations, and reduction of local and total genetic variation. As a consequence, these small populations may go extinct in the long-term. The ocelot (Leopardus pardalis, originally distributed from Texas to southern Brazil and northern Argentina, has been impacted by habitat fragmentation throughout much of its range. To test whether habitat fragmentation has already induced genetic differentiation in an area where this process has been documented for a larger felid (jaguars, we analyzed molecular variation in ocelots inhabiting two Atlantic Forest fragments, Morro do Diabo (MD and Iguaçu Region (IR. Analyses using nine microsatellites revealed mean observed and expected heterozygosity of 0.68 and 0.70, respectively. The MD sampled population showed evidence of a genetic bottleneck under two mutational models (TPM = 0.03711 and SMM = 0.04883. Estimates of genetic structure (FST = 0.027; best fit of k = 1 with STRUCTURE revealed no meaningful differentiation between these populations. Thus, our results indicate that the ocelot populations sampled in these fragments are still not significantly different genetically, a pattern that strongly contrasts with that previously observed in jaguars for the same comparisons. This observation is likely due to a combination of two factors: (i larger effective population size of ocelots (relative to jaguars in each fragment, implying a slower effect of drift-induced differentiation; and (ii potentially some remaining permeability of the anthropogenic matrix for ocelots, as opposed to the observed lack of permeability for jaguars. The persistence of ocelot gene flow between these areas must be prioritized in long-term conservation planning on behalf of these felids.

  15. ALIEN SPECIES: THEIR ROLE IN AMPHIBIAN POPULATION DECLINES AND RESTORATION

    Science.gov (United States)

    Alien species (also referred to as exotic, invasive, introduced, or normative species) have been implicated as causal agents in population declines of many amphibian species. Herein, we evaluate the relative contributions of alien species and other factors in adversely affecting ...

  16. Lack of access and continuity of adult health care: a national population-based survey.

    Science.gov (United States)

    Dilélio, Alitéia Santiago; Tomasi, Elaine; Thumé, Elaine; Silveira, Denise Silva da; Siqueira, Fernando Carlos Vinholes; Piccini, Roberto Xavier; Silva, Suele Manjourany; Nunes, Bruno Pereira; Facchini, Luiz Augusto

    2015-01-01

    OBJECTIVE To describe the lack of access and continuity of health care in adults. METHODS A cross-sectional population-based study was performed on a sample of 12,402 adults aged 20 to 59 years in urban areas of 100 municipalities of 23 states in the five Brazilian geopolitical regions. Barriers to the access and continuity of health care and were investigated based on receiving, needing and seeking health care (hospitalization and accident/emergency care in the last 12 months; care provided by a doctor, by other health professional or home care in the last three months). Based on the results obtained by the description of the sample, a projection is provided for adults living in Brazilian urban areas. RESULTS The highest prevalence of lack of access to health services and to provision of care by health professionals was for hospitalization (3.0%), whilst the lowest prevalence was for care provided by a doctor (1.1%). The lack of access to care provided by other health professionals was 2.0%; to accident and emergency services, 2.1%; and to home care, 2.9%. As for prevalences, the greatest absolute lack of access occurred in emergency care (more than 360,000 adults). The main reasons were structural and organizational problems, such as unavailability of hospital beds, of health professionals, of appointments for the type of care needed and charges made for care. CONCLUSIONS The universal right to health care in Brazil has not yet been achieved. These projections can help health care management in scaling the efforts needed to overcome this problem, such as expanding the infrastructure of health services and the workforce.

  17. Population dynamics of species-rich ecosystems: the mixture of matrix population models approach

    DEFF Research Database (Denmark)

    Mortier, Frédéric; Rossi, Vivien; Guillot, Gilles

    2013-01-01

    Matrix population models are widely used to predict population dynamics, but when applied to species-rich ecosystems with many rare species, the small population sample sizes hinder a good fit of species-specific models. This issue can be overcome by assigning species to groups to increase the size...... species with similar population dynamics....

  18. Relative lack of regeneration of shade-intolerant canopy species in some South African forests

    CSIR Research Space (South Africa)

    Midgley, JJ

    1995-01-01

    Full Text Available tent to have higher concentrations of leaf nitrogen, suggesting that they are shade-intolerant species. Similarly the canopy species which are recruiting adequately have low level of leaf nitrogen....

  19. Induction of competence for genetic transformation by antibiotics: convergent evolution of stress responses in distant bacterial species lacking SOS?

    Science.gov (United States)

    Charpentier, Xavier; Polard, Patrice; Claverys, Jean-Pierre

    2012-10-01

    Bacterial transformation is a programmed process resulting in genetic transfer and diversity. It relies on the development of competence via regulatory circuits which are diverse and tailored to the particular lifestyle of each species. Despite this diversity, some species have been reported to trigger competence in response to antibiotics. Here, we review these recent findings, which reinforce the view that competence is a stress response and can substitute for SOS in bacteria lacking it. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Evolution of reduced post-copulatory molecular interactions in Drosophila populations lacking sperm competition.

    Science.gov (United States)

    Hollis, B; Houle, D; Kawecki, T J

    2016-01-01

    In many species with internal fertilization, molecules transferred in the male ejaculate trigger and interact with physiological changes in females. It is controversial to what extent these interactions between the sexes act synergistically to mediate the female switch to a reproductive state or instead reflect sexual antagonism evolved as a by product of sexual selection on males. To address this question, we eliminated sexual selection by enforcing monogamy in populations of Drosophila melanogaster for 65 generations and then measured the expression of male seminal fluid protein genes and genes involved in the female response to mating. In the absence of sperm competition, male and female reproductive interests are perfectly aligned and any antagonism should be reduced by natural selection. Consistent with this idea, males from monogamous populations showed reduced expression of seminal fluid protein genes, 16% less on average than in polygamous males. Further, we identified 428 genes that responded to mating in females. After mating, females with an evolutionary history of monogamy exhibited lower relative expression of genes that were up regulated in response to mating and higher expression of genes that were down-regulated--in other words, their post-mating transcriptome appeared more virgin-like. Surprisingly, these genes showed a similar pattern even before mating, suggesting that monogamous females evolved to be less poised for mating and the accompanying receipt of male seminal fluid proteins. This reduced investment by both monogamous males and females in molecules involved in post-copulatory interactions points to a pervasive role of sexual conflict in shaping these interactions. © 2015 The Authors. Journal of Evolutionary Biology published by John Wiley & Sons Ltd on behalf of European Society for Evolutionary Biology.

  1. Respiratory adaptations to oxygen lack in three species of Glossiphoniidae (Hirudinea) in Lake Esrom, Denmark

    DEFF Research Database (Denmark)

    Pohle, B. D.; Hamburger, K.

    2005-01-01

    The weight-specific respiration rate (µl O2 mg-1 AFDW h-1) of three species of leech from Lake Esrom, Denmark, Glossiphonia concolor, G. complanata and Helobdella stagnalis was measured in a closed stirred chamber with a micro electrode. At declining oxygen concentration (mg O2 l-1) all three...

  2. Novel RAD sequence data reveal a lack of genomic divergence between dietary ecotypes in a landlocked salmonid population

    Science.gov (United States)

    Limborg, Morten T.; Larson, Wesley; Shedd, Kyle; Seeb, Lisa W.; Seeb, James E.

    2017-01-01

    Preservation of heritable ecological diversity within species and populations is a key challenge for managing natural resources and wild populations. Salmonid fish are iconic and socio-economically important species for commercial, aquaculture, and recreational fisheries across the globe. Many salmonids are known to exhibit ecological divergence within species, including distinct feeding ecotypes within the same lakes. Here we used 5559 SNPs, derived from RAD sequencing, to perform population genetic comparisons between two dietary ecotypes of sockeye salmon (Oncorhynchus nerka) in Jo-Jo Lake, Alaska (USA). We tested the standing hypothesis that these two ecotypes are currently diverging as a result of adaptation to distinct dietary niches; results support earlier conclusions of a single panmictic population. The RAD sequence data revealed 40 new SNPs not previously detected in the species, and our sequence data can be used in future studies of ecotypic diversity in salmonid species.

  3. Casting light on xylem vulnerability in an herbaceous species reveals a lack of segmentation.

    Science.gov (United States)

    Skelton, Robert P; Brodribb, Timothy J; Choat, Brendan

    2017-04-01

    Finding thresholds at which loss of plant functionality occurs during drought is critical for predicting future crop productivity and survival. Xylem resistance to embolism has been suggested as a key trait associated with water-stress tolerance. Although a substantial literature exists describing the vulnerability of woody stems to embolism, leaves and roots of herbaceous species remain under-represented. Also, little is known about vulnerability to embolism at a whole-plant scale or propagation of embolism within plants. New techniques to view the process of embolism formation provide opportunities to resolve long-standing questions. Here, we used multiple visual techniques, including X-ray micro-computed tomography and the optical vulnerability method, to investigate the spread of embolism within intact stems, leaves and roots of Solanum lycopersicum (common tomato). We found that roots, stems and leaves of tomato plants all exhibited similar vulnerability to embolism, suggesting that embolism rapidly propagates among tissues. Although we found scarce evidence for differentiation of xylem vulnerability among tissues at the scale of the whole plant, within a leaf the midrib embolized at higher water potentials than lower order veins. Substantial overlap between the onset of cavitation and incipient leaf damage suggests that cavitation represents a substantial damage to plants, but the point of lethal cavitation in this herbaceous species remains uncertain. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  4. VBORNET gap analysis: Mosquito vector distribution models utilised to identify areas of potential species distribution in areas lacking records.

    Directory of Open Access Journals (Sweden)

    Francis Schaffner

    2016-12-01

    Full Text Available This is the second of a number of planned data papers presenting modelled vector distributions produced originally during the ECDC funded VBORNET project. This work continues under the VectorNet project now jointly funded by ECDC and EFSA. Further data papers will be published after sampling seasons when more field data will become available allowing further species to be modelled or validation and updates to existing models.  The data package described here includes those mosquito species first modelled in 2013 & 2014 as part of the VBORNET gap analysis work which aimed to identify areas of potential species distribution in areas lacking records. It comprises three species models together with suitability masks based on land class and environmental limits. The species included as part of this phase are the mosquitoes 'Aedes vexans', 'Anopheles plumbeus' and 'Culex modestus'. The known distributions of these species within the area covered by the project (Europe, the ­Mediterranean Basin, North Africa, and Eurasia are currently incomplete to a greater or lesser degree. The models are designed to fill the gaps with predicted distributions, to provide a assistance in ­targeting surveys to collect distribution data for those areas with no field validated information, and b a first indication of the species distributions within the project areas.

  5. Lack of congruence in species diversity indices and community structures of planktonic groups based on local environmental factors.

    Science.gov (United States)

    Doi, Hideyuki; Chang, Kwang-Hyeon; Nishibe, Yuichiro; Imai, Hiroyuki; Nakano, Shin-ichi

    2013-01-01

    The importance of analyzing the determinants of biodiversity and community composition by using multiple trophic levels is well recognized; however, relevant data are lacking. In the present study, we investigated variations in species diversity indices and community structures of the plankton taxonomic groups-zooplankton, rotifers, ciliates, and phytoplankton-under a range of local environmental factors in pond ecosystems. For each planktonic group, we estimated the species diversity index by using linear models and analyzed the community structure by using canonical correspondence analysis. We showed that the species diversity indices and community structures varied among the planktonic groups and according to local environmental factors. The observed lack of congruence among the planktonic groups may have been caused by niche competition between groups with similar trophic guilds or by weak trophic interactions. Our findings highlight the difficulty of predicting total biodiversity within a system, based upon a single taxonomic group. Thus, to conserve the biodiversity of an ecosystem, it is crucial to consider variations in species diversity indices and community structures of different taxonomic groups, under a range of local conditions.

  6. VBORNET Gap Analysis: Sand Fly Vector Distribution Models Utilised to Identify Areas of Potential Species Distribution in Areas Lacking Records

    Directory of Open Access Journals (Sweden)

    Bulent Alten

    2016-12-01

    Full Text Available This is the first of a number of planned data papers presenting modelled vector distributions, the models in this paper were produced during the ECDC funded VBORNET project. This work continues under the VectorNet project now jointly funded by ECDC and EFSA. This data paper contains the sand fly model outputs produced as part of the VBORNET project. Further data papers will be published after sampling seasons when more field data will become available allowing further species to be modelled or validation and updates to existing models. The data package described here includes those sand fly species first modelled in 2013 and 2014 as part of the VBORNET gap analysis work which aimed to identify areas of potential species distribution in areas lacking records. It comprises four species models together with suitability masks based on land class and environmental limits. The species included within this paper are 'Phlebotomus ariasi', 'Phlebotomus papatasi', 'Phlebotomus perniciosus' and 'Phlebotomus tobbi'. The known distributions of these species within the project area (Europe, the Mediterranean Basin, North Africa, and Eurasia are currently incomplete to a greater or lesser degree. The models are designed to fill the gaps with predicted distributions, to provide a assistance in targeting surveys to collect ­distribution data for those areas with no field validated information, and b a first indication of project wide distributions.

  7. Extreme streams: species persistence and genomic change in montane insect populations across a flooding gradient.

    Science.gov (United States)

    Poff, N LeRoy; Larson, Erin I; Salerno, Patricia E; Morton, Scott G; Kondratieff, Boris C; Flecker, Alexander S; Zamudio, Kelly R; Funk, W Chris

    2018-04-01

    The ecological and evolutionary consequences of extreme events are poorly understood. Here, we tested predictions about species persistence and population genomic change in aquatic insects in 14 Colorado mountain streams across a hydrological disturbance gradient caused by a one in 500-year rainfall event. Taxa persistence ranged from 39 to 77% across sites and declined with increasing disturbance in relation to species' resistance and resilience traits. For taxa with mobile larvae and terrestrial adult stages present at the time of the flood, average persistence was 84% compared to 25% for immobile taxa that lacked terrestrial adults. For two of six species analysed, genomic diversity (allelic richness) declined after the event. For one species it greatly expanded, suggesting resilience via re-colonisation from upstream populations. Thus, while resistance and resilience traits can explain species persistence to extreme disturbance, population genomic change varies among species, challenging generalisations about evolutionary responses to extreme events at landscape scales. © 2018 John Wiley & Sons Ltd/CNRS.

  8. Cercospora zeina from Maize in South Africa Exhibits High Genetic Diversity and Lack of Regional Population Differentiation.

    Science.gov (United States)

    Muller, Mischa F; Barnes, Irene; Kunene, Ncobile T; Crampton, Bridget G; Bluhm, Burton H; Phillips, Sonia M; Olivier, Nicholas A; Berger, Dave K

    2016-10-01

    South Africa is one of the leading maize-producing countries in sub-Saharan Africa. Since the 1980s, Cercospora zeina, a causal agent of gray leaf spot of maize, has become endemic in South Africa, and is responsible for substantial yield reductions. To assess genetic diversity and population structure of C. zeina in South Africa, 369 isolates were collected from commercial maize farms in three provinces (KwaZulu-Natal, Mpumalanga, and North West). These isolates were evaluated with 14 microsatellite markers and species-specific mating type markers that were designed from draft genome sequences of C. zeina isolates from Africa (CMW 25467) and the United States (USPA-4). Sixty alleles were identified across 14 loci, and gene diversity values within each province ranged from 0.18 to 0.35. High levels of gene flow were observed (Nm = 5.51), and in a few cases, identical multilocus haplotypes were found in different provinces. Overall, 242 unique multilocus haplotypes were identified with a low clonal fraction of 34%. No distinct population clusters were identified using STRUCTURE, principal coordinate analysis, or Weir's theta θ statistic. The lack of population differentiation was supported by analysis of molecular variance tests, which indicated that only 2% of the variation was attributed to variability between populations from each province. Mating type ratios of MAT1-1 and MAT1-2 idiomorphs from 335 isolates were not significantly different from a 1:1 ratio in all provinces, which provided evidence for sexual reproduction. The draft genome of C. zeina CMW 25467 exhibited a complete genomic copy of the MAT1-1 idiomorph as well as exonic fragments of MAT genes from both idiomorphs. The high level of gene diversity, shared haplotypes at different geographical locations within South Africa, and presence of both MAT idiomorphs at all sites indicates widespread dispersal of C. zeina between maize fields in the country as well as evidence for sexual recombination. The

  9. Lack of satellite DNA species-specific homogenization and relationship to chromosomal rearrangements in monitor lizards (Varanidae, Squamata).

    Science.gov (United States)

    Prakhongcheep, Ornjira; Thapana, Watcharaporn; Suntronpong, Aorarat; Singchat, Worapong; Pattanatanang, Khampee; Phatcharakullawarawat, Rattanin; Muangmai, Narongrit; Peyachoknagul, Surin; Matsubara, Kazumi; Ezaz, Tariq; Srikulnath, Kornsorn

    2017-08-16

    Satellite DNAs (stDNAs) are highly repeated sequences that constitute large portions of any genome. The evolutionary dynamics of stDNA (e.g. copy number, nucleotide sequence, location) can, therefore, provide an insight into genome organization and evolution. We investigated the evolutionary origin of VSAREP stDNA in 17 monitor lizards (seven Asian, five Australian, and five African) at molecular and cytogenetic level. Results revealed that VSAREP is conserved in the genome of Asian and Australian varanids, but not in African varanids, suggesting that these sequences are either differentiated or lost in the African varanids. Phylogenetic and arrangement network analyses revealed the existence of at least four VSAREP subfamilies. The similarity of each sequence unit within the same VSAREP subfamily from different species was higher than those of other VSAREP subfamilies belonging to the same species. Additionally, all VSAREP subfamilies isolated from the three Australian species (Varanus rosenbergi, V. gouldii, and V. acanthurus) were co-localized near the centromeric or pericentromeric regions of the macrochromosomes, except for chromosomes 3 and 4 in each Australian varanid. However, their chromosomal arrangements were different among species. The VSAREP stDNA family lack homogenized species-specific nucleotide positions in varanid lineage. Most VSAREP sequences were shared among varanids within the four VSAREP subfamilies. This suggests that nucleotide substitutions in each varanid species accumulated more slowly than homogenization rates in each VSAREP subfamily, resulting in non-species-specific evolution of stDNA profiles. Moreover, changes in location of VSAREP stDNA in each Australian varanid suggests a correlation with chromosomal rearrangements, leading to karyotypic differences among these species.

  10. Population genetic divergence corresponds with species-level biodiversity patterns in the large genus Begonia.

    Science.gov (United States)

    Hughes, M; Hollingsworth, P M

    2008-06-01

    Begonia is one of the largest angiosperm genera, containing over 1500 species. Some aspects of the distribution of biodiversity in the genus, such as the geographical restrictions of monophyletic groups, the rarity and morphological variability of widespread species, and a preponderance of narrow endemics, suggest that restricted gene flow may have been a factor in the formation of so many species. In order to investigate whether this inference based on large-scale patterns is supported by data at the population level, we examined the distribution of genetic variation within Begonia sutherlandii in the indigenous forests of Kwazulu-Natal, South Africa, using microsatellite markers. Despite the species being predominantly outbreeding, we found high and significant levels of population structure (standardized =F'ST= 0.896). Even within individual populations, there was evidence for clear differentiation of subpopulations. There is thus congruence in evolutionary patterns ranging from interspecific phylogeny, the distribution of individual species, to the levels of population differentiation. Despite this species-rich genus showing a pan-tropical distribution, these combined observations suggest that differentiation occurs over very local scales. Although strongly selected allelic variants can maintain species cohesion with only low levels of gene flow, we hypothesize that in Begonia, gene flow levels are often so low, that divergence in allopatry is likely to be a frequent occurrence, and the lack of widespread species may in part be attributable to a lack of a mechanism for holding them together.

  11. Human population, grasshopper and plant species richness in European countries

    Science.gov (United States)

    Steck, Claude E.; Pautasso, Marco

    2008-11-01

    Surprisingly, several studies over large scales have reported a positive spatial correlation of people and biodiversity. This pattern has important implications for conservation and has been documented for well studied taxa such as plants, amphibians, reptiles, birds and mammals. However, it is unknown whether the pattern applies also to invertebrates other than butterflies and more work is needed to establish whether the species-people relationship is explained by both variables correlating with other environmental factors. We studied whether grasshopper species richness (Orthoptera, suborder Caelifera) is related to human population size in European countries. As expected, the number of Caelifera species increases significantly with increasing human population size. But this is not the case when controlling for country area, latitude and number of plant species. Variations in Caelifera species richness are primarily associated with variations in plant species richness. Caelifera species richness also increases with decreasing mean annual precipitation, Gross Domestic Product per capita (used as an indicator for economic development) and net fertility rate of the human population. Our analysis confirms the hypothesis that the broad-scale human population-biodiversity correlations can be explained by concurrent variations in factors other than human population size such as plant species richness, environmental productivity, or habitat heterogeneity. Nonetheless, more populated countries in Europe still have more Caelifera species than less populated countries and this poses a particular challenge for conservation.

  12. Soil Populations of Fusarium Species at Lobamba Lomdzala ...

    African Journals Online (AJOL)

    Fusarium species whose members have telomorphs in the Gibberella fujikuroi species complex are one of the major groups of pathogens that cause diseases of maize. Mating population A (pink Fusarium m moniliforme) and mating population f (yellow fusarium moniliforme) which had shared the Fusarium Moniliforme and ...

  13. Lack of genetic structure in greylag goose (Anser anser) populations along the European Atlantic flyway

    OpenAIRE

    Pellegrino, Irene; Cucco, Marco; Follestad, Arne; Boos, Mathieu

    2015-01-01

    Greylag goose populations are steadily increasing in north-western Europe. Although individuals breeding in the Netherlands have been considered mainly sedentary birds, those fromScandinavia or northern Germany fly towards their winter quarters, namely over France as far as Spain. This study aimed to determine the genetic structure of these birds, and to evaluate how goose populations mix. We used mitochondrial DNA and microsatellites from individuals distributed throughout ...

  14. Population-specific responses to an invasive species.

    Science.gov (United States)

    Reichard, Martin; Douda, Karel; Przybyłski, Mirosław; Popa, Oana P; Karbanová, Eva; Matasová, Klára; Rylková, Kateřina; Polačik, Matej; Blažek, Radim; Smith, Carl

    2015-08-07

    Predicting the impacts of non-native species remains a challenge. As populations of a species are genetically and phenotypically variable, the impact of non-native species on local taxa could crucially depend on population-specific traits and adaptations of both native and non-native species. Bitterling fishes are brood parasites of unionid mussels and unionid mussels produce larvae that parasitize fishes. We used common garden experiments to measure three key elements in the bitterling-mussel association among two populations of an invasive mussel (Anodonta woodiana) and four populations of European bitterling (Rhodeus amarus). The impact of the invasive mussel varied between geographically distinct R. amarus lineages and between local populations within lineages. The capacity of parasitic larvae of the invasive mussel to exploit R. amarus was higher in a Danubian than in a Baltic R. amarus lineage and in allopatric than in sympatric R. amarus populations. Maladaptive oviposition by R. amarus into A. woodiana varied among populations, with significant population-specific consequences for R. amarus recruitment. We suggest that variation in coevolutionary states may predispose different populations to divergent responses. Given that coevolutionary relationships are ubiquitous, population-specific attributes of invasive and native populations may play a critical role in the outcome of invasion. We argue for a shift from a species-centred to population-centred perspective of the impacts of invasions. © 2015 The Author(s).

  15. Molecular species identification and population genetics of ...

    African Journals Online (AJOL)

    Molecular genetic techniques, such as DNA barcoding and genotyping, are increasingly being used to assist with the conservation and management of chondrichthyans worldwide. Southern Africa is a shark biodiversity hotspot, with a large number of endemic species. According to the IUCN Red List, a quarter of South ...

  16. Origin of Boundary Populations in Medaka (Oryzias latipes Species Complex).

    Science.gov (United States)

    Takehana, Yusuke; Sakai, Masato; Narita, Takanori; Sato, Tadashi; Naruse, Kiyoshi; Sakaizumi, Mitsuru

    2016-04-01

    The Japanese wild population of the medaka fish (Oryzias latipes species complex) comprises two genetically distinct groups, the Northern and the Southern Populations, with boundary populations having a unique genotype. It is thought that the boundary populations have been formed through introgressive hybridization between the two groups, because they are fixed with the Northern alleles at two allozymic loci, with the Southern alleles at two other loci, and have a unique allele at one locus. In this study, we examined the genetic population structure of the boundary populations using genome-wide single nucleotide polymorphism (SNP) data. Most SNPs of the Toyooka population, a typical boundary population, were shared with the Northern Population, some were shared with the Southern Population, and the remaining SNPs were unique to this population, suggesting that the boundary populations originated and diverged from the Northern Population. Further analyses of different populations using SNPs at eight genomic loci indicated that the boundary populations at different locations share similar genomic constitutions, and can be genetically distinguished from typical Northern Populations by unique SNPs. In addition, the boundary populations in the Maruyama River Basin had Northern mitochondrial DNA (mtDNA), while others, from the Fukuda and Kishida River Basins and from the Kumihama Bay area, had Southern mtDNA. These findings suggested that the boundary populations originated from the Northern Population, and then their genomes diverged as a result of geographical isolation, followed by mtDNA introgression from the Southern Population that occurred independently in some populations.

  17. Lack of genetic structure in greylag goose (Anser anser populations along the European Atlantic flyway

    Directory of Open Access Journals (Sweden)

    Irene Pellegrino

    2015-08-01

    Full Text Available Greylag goose populations are steadily increasing in north-western Europe. Although individuals breeding in the Netherlands have been considered mainly sedentary birds, those from Scandinavia or northern Germany fly towards their winter quarters, namely over France as far as Spain. This study aimed to determine the genetic structure of these birds, and to evaluate how goose populations mix. We used mitochondrial DNA and microsatellites from individuals distributed throughout the European Atlantic flyway, from breeding sites in Norway and the Netherlands to stopover and wintering sites in northern and south-western France. The mtDNA marker (CR1 D-Loop, 288 bp sequence, 144 ind. showed 23 different haplotypes. The genetic distances amongst individuals sampled in Norway, northern France and the Netherlands were low (range 0.012–0.013. Individuals in south-western France showed a slightly higher genetic distance compared to all other sampling areas (ranges 0.018–0.022. The NJ tree does not show evidence of any single clades grouping together all individuals from the same geographic area. Besides, individuals from each site are found in different branches. Bayesian clustering procedures on 14 microsatellites (169 individuals did not detect any geographically distinct cluster, and a high genetic admixture was recorded in all studied areas except for the individuals from the breeding sites in Norway, which were genetically very close. Estimation of migration rates through Bayesian inference confirms the scenario for the current mixing of goose populations.

  18. Lack of genetic structure in greylag goose (Anser anser) populations along the European Atlantic flyway.

    Science.gov (United States)

    Pellegrino, Irene; Cucco, Marco; Follestad, Arne; Boos, Mathieu

    2015-01-01

    Greylag goose populations are steadily increasing in north-western Europe. Although individuals breeding in the Netherlands have been considered mainly sedentary birds, those from Scandinavia or northern Germany fly towards their winter quarters, namely over France as far as Spain. This study aimed to determine the genetic structure of these birds, and to evaluate how goose populations mix. We used mitochondrial DNA and microsatellites from individuals distributed throughout the European Atlantic flyway, from breeding sites in Norway and the Netherlands to stopover and wintering sites in northern and south-western France. The mtDNA marker (CR1 D-Loop, 288 bp sequence, 144 ind.) showed 23 different haplotypes. The genetic distances amongst individuals sampled in Norway, northern France and the Netherlands were low (range 0.012-0.013). Individuals in south-western France showed a slightly higher genetic distance compared to all other sampling areas (ranges 0.018-0.022). The NJ tree does not show evidence of any single clades grouping together all individuals from the same geographic area. Besides, individuals from each site are found in different branches. Bayesian clustering procedures on 14 microsatellites (169 individuals) did not detect any geographically distinct cluster, and a high genetic admixture was recorded in all studied areas except for the individuals from the breeding sites in Norway, which were genetically very close. Estimation of migration rates through Bayesian inference confirms the scenario for the current mixing of goose populations.

  19. Lack of Population Structure and Mixed Reproduction Modes in Exserohilum turcicum from South Africa.

    Science.gov (United States)

    Human, Maria Petronella; Barnes, Irene; Craven, Maryke; Crampton, Bridget Genevieve

    2016-11-01

    Exserohilum turcicum is the causal agent of northern corn leaf blight, a destructive foliar disease of maize that results in yield losses worldwide. In South Africa, typical yield losses range from 15 to 30%. Previous studies found high haplotypic diversity with evidence for sexual recombination in E. turcicum populations from tropical climates such as Kenya. However, the population genetic structure and method of reproduction of E. turcicum in South Africa is unknown and, therefore, was investigated. Twelve polymorphic microsatellite markers were screened on 258 E. turcicum isolates from maize collected during 2012 and 2013 from three maize fields in South Africa. A multiplex polymerase chain reaction assay amplifying both mating type idiomorphs was applied to investigate the distribution of mating types. No distinct genetic clusters were observed. Shared haplotypes were identified between isolates separated by distances of up to 762 km, which provided evidence of migration. High haplotypic diversity indicated that sexual reproduction is occurring among E. turcicum isolates, although mating type ratios and linkage disequilibrium analyses did not support the hypothesis of random mating. The population genetic structure of E. turcicum in South Africa is likely due to the direct movement and spread of isolates undergoing a mixed reproductive lifecycle.

  20. Lack of genomic diversity in the SLC47A1 gene within the indigenous Xhosa population.

    Science.gov (United States)

    Jacobs, Clifford; Pearce, Brendon; Hoosain, Nisreen; Benjeddou, Mongi

    2016-06-01

    Multidrug and toxin extrusion 1 (MATE1) is an organic cation/H+ exchanger, localized in the apical membrane of proximal renal tubules, which mediates the cellular elimination of organic cations into the renal lumen. These organic cations include clinically important drugs such as metformin, oxaliplatin and cimetidine. Moreover, genetic polymorphisms of SLC47A1, the pharmacogenetically relevant gene encoding human MATE1, have been implicated in reduced transport or accumulation to cytotoxic levels of these drugs in vitro. However, little or no information is available on the minor allele frequency distribution of known SLC47A1 coding SNPs in the sub-Saharan African populations. Thus, the aim of this study was to determine the baseline minor allele frequency distribution of 20 known coding SNPs in the SLC47A1 gene of 148 Xhosa individuals residing in Cape Town, South Africa. This study did not identify any of these known SLC47A1 coding SNPs in the Xhosa individuals who participated in this study. It is anticipated that whole genome or exome sequencing may reveal novel SNPs in the Xhosa and other sub-Saharan African populations, which may have been missed with the current genotyping strategy.

  1. Central-marginal population dynamics in species invasions

    Directory of Open Access Journals (Sweden)

    Qinfeng eGuo

    2014-06-01

    Full Text Available The species’ range limits and associated central-marginal (C-M; i.e., from species range center to margin population dynamics continue to draw increasing attention because of their importance for current emerging issues such as biotic invasions and epidemic diseases under global change. Previous studies have mainly focused on species borders and C-M process in natural settings for native species. More recently, growing efforts are devoted to examine the C-M patterns and process for invasive species partly due to their relatively short history, highly dynamic populations, and management implications. Here I examine recent findings and information gaps related to (1 the C-M population dynamics linked to species invasions, and (2 the possible effects of climate change and land use on the C-M patterns and processes. Unlike most native species that are relatively stable (some even having contracting populations or ranges, many invasive species are still spreading fast and form new distribution or abundance centers. Because of the strong nonlinearity of population demographic or vital rates (i.e. birth, death, immigration and emigration across the C-M gradients and the increased complexity of species ranges due to habitat fragmentation, multiple introductions, range-wide C-M comparisons and simulation involving multiple vital rates are needed in the future.

  2. Lack of population genetic differentiation of a marine ovoviviparous fish Sebastes schlegelii in Northwestern Pacific.

    Science.gov (United States)

    Zhang, Hui; Yanagimoto, Takashi; Zhang, Xiumei; Song, Na; Gao, Tianxiang

    2016-05-01

    Sebastes schlegelii is one of the fishes that aggregate around drifting seaweed during early development. To examine the population genetic structure of S. schlegelii, a 452-bp fragment of the mtDNA control region was sequenced and used to interpret life history characteristics and larval dispersal strategy. Two-hundred and twenty-one individuals from 13 sites across the entire range of S. schlegelii in China, Japan and Korea were analyzed. A neighbor-joining tree and network showed that there were no significant genealogical structures corresponding to sampling locations. AMOVA, pair-wise FST and exact test revealed no significant genetic differentiation among locations. The migration rate among locations was high based on the result of LAMARC. We conclude that larval dispersal with drifting seaweed and the current environmental factors may play an important role in shaping the contemporary phylogeographic pattern and genetic homogeneity of S. schlegelii.

  3. Population trends influence species ability to track climate change.

    Science.gov (United States)

    Ralston, Joel; DeLuca, William V; Feldman, Richard E; King, David I

    2017-04-01

    Shifts of distributions have been attributed to species tracking their fundamental climate niches through space. However, several studies have now demonstrated that niche tracking is imperfect, that species' climate niches may vary with population trends, and that geographic distributions may lag behind rapid climate change. These reports of imperfect niche tracking imply shifts in species' realized climate niches. We argue that quantifying climate niche shifts and analyzing them for a suite of species reveal general patterns of niche shifts and the factors affecting species' ability to track climate change. We analyzed changes in realized climate niche between 1984 and 2012 for 46 species of North American birds in relation to population trends in an effort to determine whether species differ in the ability to track climate change and whether differences in niche tracking are related to population trends. We found that increasingly abundant species tended to show greater levels of niche expansion (climate space occupied in 2012 but not in 1980) compared to declining species. Declining species had significantly greater niche unfilling (climate space occupied in 1980 but not in 2012) compared to increasing species due to an inability to colonize new sites beyond their range peripheries after climate had changed at sites of occurrence. Increasing species, conversely, were better able to colonize new sites and therefore showed very little niche unfilling. Our results indicate that species with increasing trends are better able to geographically track climate change compared to declining species, which exhibited lags relative to changes in climate. These findings have important implications for understanding past changes in distribution, as well as modeling dynamic species distributions in the face of climate change. © 2016 John Wiley & Sons Ltd.

  4. Population trends influence species ability to track climate change

    Science.gov (United States)

    Joel Ralston; William V. DeLuca; Richard E. Feldman; David I. King

    2016-01-01

    Shifts of distributions have been attributed to species tracking their fundamental climate niches through space. However, several studies have now demonstrated that niche tracking is imperfect, that species' climate niches may vary with population trends, and that geographic distributions may lag behind rapid climate change. These reports of imperfect niche...

  5. Varying herbivore population structure correlates with lack of local adaptation in a geographic variable plant-herbivore interaction.

    Directory of Open Access Journals (Sweden)

    Rodrigo Cogni

    Full Text Available Local adaptation of parasites to their hosts due to coevolution is a central prediction of many theories in evolutionary biology. However, empirical studies looking for parasite local adaptation show great variation in outcomes, and the reasons for such variation are largely unknown. In a previous study, we showed adaptive differentiation in the arctiid moth Utetheisa ornatrix to its host plant, the pyrrolizidine alkaloid-bearing legume Crotalaria pallida, at the continental scale, but found no differentiation at the regional scale. In the present study, we sampled the same sites to investigate factors that may contribute to the lack of differentiation at the regional scale. We performed field observations that show that specialist and non-specialist polyphagous herbivore incidence varies among populations at both scales. With a series of common-garden experiments we show that some plant traits that may affect herbivory (pyrrolizidine alkaloids and extrafloral nectaries vary at the regional scale, while other traits (trichomes and nitrogen content just vary at the continental scale. These results, combined with our previous evidence for plant population differentiation based on larval performance on fresh fruits, suggest that U. ornatrix is subjected to divergent selection even at the regional scale. Finally, with a microsatellite study we investigated population structure of U. ornatrix. We found that population structure is not stable over time: we found population differentiation at the regional scale in the first year of sampling, but not in the second year. Unstable population structure of the herbivore is the most likely cause of the lack of regional adaptation.

  6. Varying Herbivore Population Structure Correlates with Lack of Local Adaptation in a Geographic Variable Plant-Herbivore Interaction

    Science.gov (United States)

    Cogni, Rodrigo; Trigo, José R.; Futuyma, Douglas J.

    2011-01-01

    Local adaptation of parasites to their hosts due to coevolution is a central prediction of many theories in evolutionary biology. However, empirical studies looking for parasite local adaptation show great variation in outcomes, and the reasons for such variation are largely unknown. In a previous study, we showed adaptive differentiation in the arctiid moth Utetheisa ornatrix to its host plant, the pyrrolizidine alkaloid-bearing legume Crotalaria pallida, at the continental scale, but found no differentiation at the regional scale. In the present study, we sampled the same sites to investigate factors that may contribute to the lack of differentiation at the regional scale. We performed field observations that show that specialist and non-specialist polyphagous herbivore incidence varies among populations at both scales. With a series of common-garden experiments we show that some plant traits that may affect herbivory (pyrrolizidine alkaloids and extrafloral nectaries) vary at the regional scale, while other traits (trichomes and nitrogen content) just vary at the continental scale. These results, combined with our previous evidence for plant population differentiation based on larval performance on fresh fruits, suggest that U. ornatrix is subjected to divergent selection even at the regional scale. Finally, with a microsatellite study we investigated population structure of U. ornatrix. We found that population structure is not stable over time: we found population differentiation at the regional scale in the first year of sampling, but not in the second year. Unstable population structure of the herbivore is the most likely cause of the lack of regional adaptation. PMID:22220208

  7. Founding population size of an aquatic invasive species

    Science.gov (United States)

    Kalinowski, Steven T.; Muhlfeld, Clint C.; Guy, Christopher S.; Benjamin Cox,

    2010-01-01

    Non-native species of fish threaten native fishes throughout North America, and in the Rocky Mountains, introduced populations of lake trout threaten native populations of bull trout. Effective management of lake trout and other exotic species require understanding the dynamics of invasion in order to either suppress non-native populations or to prevent their spread. In this study, we used microsatellite genetic data to estimate the number of lake trout that invaded a population of bull trout in Swan Lake, MT. Examination of genetic diversity and allele frequencies within the Swan Lake populations showed that most of the genes in the lake trout population are descended from two founders. This emphasizes the importance of preventing even a few lake trout from colonizing new territory.

  8. Phenotypic plasticity and population differentiation in an ongoing species invasion.

    Directory of Open Access Journals (Sweden)

    Silvia Matesanz

    Full Text Available The ability to succeed in diverse conditions is a key factor allowing introduced species to successfully invade and spread across new areas. Two non-exclusive factors have been suggested to promote this ability: adaptive phenotypic plasticity of individuals, and the evolution of locally adapted populations in the new range. We investigated these individual and population-level factors in Polygonum cespitosum, an Asian annual that has recently become invasive in northeastern North America. We characterized individual fitness, life-history, and functional plasticity in response to two contrasting glasshouse habitat treatments (full sun/dry soil and understory shade/moist soil in 165 genotypes sampled from nine geographically separate populations representing the range of light and soil moisture conditions the species inhabits in this region. Polygonum cespitosum genotypes from these introduced-range populations expressed broadly similar plasticity patterns. In response to full sun, dry conditions, genotypes from all populations increased photosynthetic rate, water use efficiency, and allocation to root tissues, dramatically increasing reproductive fitness compared to phenotypes expressed in simulated understory shade. Although there were subtle among-population differences in mean trait values as well as in the slope of plastic responses, these population differences did not reflect local adaptation to environmental conditions measured at the population sites of origin. Instead, certain populations expressed higher fitness in both glasshouse habitat treatments. We also compared the introduced-range populations to a single population from the native Asian range, and found that the native population had delayed phenology, limited functional plasticity, and lower fitness in both experimental environments compared with the introduced-range populations. Our results indicate that the future spread of P. cespitosum in its introduced range will likely be

  9. Single species victory in a two-site, two-species model of population dispersion

    Science.gov (United States)

    Waddell, Jack; Sander, Len; Kessler, David

    2008-03-01

    We study the behavior of two species, differentiated only by their dispersal rates in an environment providing heterogeneous growth rates. Previous deterministic studies have shown that the slower-dispersal species always drives the faster species to extinction, while stochastic studies show that the opposite case can occur given small enough population and spatial heterogeneity. Other models of similar systems demonstrate the existence of an optimum dispersal rate, suggesting that distinguishing the species as faster or slower is insufficient. We here study the interface of these models for a small spatial system and determine the conditions of stability for a single species outcome.

  10. High quality long-term CD4+ and CD8+ effector memory populations stimulated by DNA-LACK/MVA-LACK regimen in Leishmania major BALB/c model of infection.

    Science.gov (United States)

    Sánchez-Sampedro, Lucas; Gómez, Carmen Elena; Mejías-Pérez, Ernesto; Sorzano, Carlos Oscar S; Esteban, Mariano

    2012-01-01

    Heterologous vaccination based on priming with a plasmid DNA vector and boosting with an attenuated vaccinia virus MVA recombinant, with both vectors expressing the Leishmania infantum LACK antigen (DNA-LACK and MVA-LACK), has shown efficacy conferring protection in murine and canine models against cutaneus and visceral leishmaniasis, but the immune parameters of protection remain ill defined. Here we performed by flow cytometry an in depth analysis of the T cell populations induced in BALB/c mice during the vaccination protocol DNA-LACK/MVA-LACK, as well as after challenge with L. major parasites. In the adaptive response, there is a polyfunctional CD4(+) and CD8(+) T cell activation against LACK antigen. At the memory phase the heterologous vaccination induces high quality LACK-specific long-term CD4(+) and CD8(+) effector memory cells. After parasite challenge, there is a moderate boosting of LACK-specific CD4(+) and CD8(+) T cells. Anti-vector responses were largely CD8(+)-mediated. The immune parameters induced against LACK and triggered by the combined vaccination DNA/MVA protocol, like polyfunctionality of CD4(+) and CD8(+) T cells with an effector phenotype, could be relevant in protection against leishmaniasis.

  11. INDICATOR SPECIES POPULATION MONITORING IN ANTARCTICA WITH UAV

    Directory of Open Access Journals (Sweden)

    A. Zmarz

    2015-08-01

    Full Text Available A program to monitor bird and pinniped species in the vicinity of Arctowski Station, King George Island, South Shetlands, Antarctica, has been conducted over the past 38 years. Annual monitoring of these indicator species includes estimations of breeding population sizes of three Pygoscelis penguin species: Adélie, gentoo and chinstrap. Six penguin colonies situated on the western shores of two bays: Admiralty and King George are investigated. To study changes in penguin populations Unmanned Aerial Vehicles were used for the first time in the 2014/15 austral summer season. During photogrammetric flights the high-resolution images of eight penguin breeding colonies were taken. Obtained high resolution images were used for estimation of breeding population size and compared with the results of measurements taken at the same time from the ground. During this Antarctic expedition eight successful photogrammetry missions (total distance 1500 km were performed. Images were taken with digital SLR Canon 700D, Nikon D5300, Nikon D5100 with a 35mm objective lens. Flights altitude at 350 – 400 AGL, allowed images to be taken with a resolution GSD (ground sample distance less than 5 cm. The Image J software analysis method was tested to provide automatic population estimates from obtained images. The use of UAV for monitoring of indicator species, enabled data acquisition from areas inaccessible by ground methods.

  12. Indicator Species Population Monitoring in Antarctica with Uav

    Science.gov (United States)

    Zmarz, A.; Korczak-Abshire, M.; Storvold, R.; Rodzewicz, M.; Kędzierska, I.

    2015-08-01

    A program to monitor bird and pinniped species in the vicinity of Arctowski Station, King George Island, South Shetlands, Antarctica, has been conducted over the past 38 years. Annual monitoring of these indicator species includes estimations of breeding population sizes of three Pygoscelis penguin species: Adélie, gentoo and chinstrap. Six penguin colonies situated on the western shores of two bays: Admiralty and King George are investigated. To study changes in penguin populations Unmanned Aerial Vehicles were used for the first time in the 2014/15 austral summer season. During photogrammetric flights the high-resolution images of eight penguin breeding colonies were taken. Obtained high resolution images were used for estimation of breeding population size and compared with the results of measurements taken at the same time from the ground. During this Antarctic expedition eight successful photogrammetry missions (total distance 1500 km) were performed. Images were taken with digital SLR Canon 700D, Nikon D5300, Nikon D5100 with a 35mm objective lens. Flights altitude at 350 - 400 AGL, allowed images to be taken with a resolution GSD (ground sample distance) less than 5 cm. The Image J software analysis method was tested to provide automatic population estimates from obtained images. The use of UAV for monitoring of indicator species, enabled data acquisition from areas inaccessible by ground methods.

  13. How to conserve threatened Chinese plant species with extremely small populations?

    Directory of Open Access Journals (Sweden)

    Sergei Volis

    2016-02-01

    Full Text Available The Chinese flora occupies a unique position in global plant diversity, but is severely threatened. Although biodiversity conservation in China has made significant progress over the past decades, many wild plant species have extremely small population sizes and therefore are in extreme danger of extinction. The concept of plant species with extremely small populations (PSESPs, recently adopted and widely accepted in China, lacks a detailed description of the methodology appropriate for conserving PSESPs. Strategies for seed sampling, reintroduction, protecting PSESP locations, managing interactions with the local human population, and other conservation aspects can substantially differ from those commonly applied to non-PSESPs. The present review is an attempt to provide a detailed conservation methodology with realistic and easy-to-follow guidelines for PSESPs in China.

  14. Is colour polymorphism advantageous to populations and species?

    Science.gov (United States)

    Forsman, Anders

    2016-06-01

    I am writing in response to an article by Bolton, Rollins and Griffith (2015) entitled 'The danger within: the role of genetic, behavioural and ecological factors in population persistence of colour polymorphic species' that was recently published as an Opinion under the NEWS AND VIEWS section in Molecular Ecology. Bolton et al. (Molecular Ecology, 2015, 24, 2907) argue that colour polymorphism may reduce population fitness and increase extinction risk and emphasize that this is contrary to predictions put forward by Forsman et al. (Ecology, 89, 2008, 34) and Wennersten & Forsman (Biological Reviews 87, 2012, 756) that the existence of multiple colour morphs with co-adapted gene complexes and associated trait values may increase the ecological and evolutionary success of polymorphic populations and species. Bolton et al. (Molecular Ecology, 2015, 24, 2907) further state that there is no clear evidence from studies of 'true polymorphic species' that polymorphism promotes population persistence. In response, I (i) challenge their classifications of polymorphisms and revisit the traditional definitions recognizing the dynamic nature of polymorphisms, (ii) review empirical studies that have examined whether and how polymorphism is associated with extinction risk, (iii) discuss the roles of trait correlations between colour pattern and other phenotypic dimensions for population fitness and (iv) highlight that the causes and mechanisms that influence the composition and maintenance of polymorphisms are different from the consequences of the polymorphic condition and how it may impact on aspects of ecological success and long-term persistence of populations and species. © 2016 John Wiley & Sons Ltd.

  15. Global Asymptotic Stability for Discrete Single Species Population Models

    Directory of Open Access Journals (Sweden)

    A. Bilgin

    2017-01-01

    Full Text Available We present some basic discrete models in populations dynamics of single species with several age classes. Starting with the basic Beverton-Holt model that describes the change of single species we discuss its basic properties such as a convergence of all solutions to the equilibrium, oscillation of solutions about the equilibrium solutions, Allee’s effect, and Jillson’s effect. We consider the effect of the constant and periodic immigration and emigration on the global properties of Beverton-Holt model. We also consider the effect of the periodic environment on the global properties of Beverton-Holt model.

  16. Lack of divergence in seed ecology of two Amphicarpaea (Fabaceae) species disjunct between eastern Asia and eastern North America.

    Science.gov (United States)

    Zhang, Keliang; Baskin, Jerry M; Baskin, Carol C; Yang, Xuejun; Huang, Zhenying

    2015-06-01

    Many congeneric species are disjunct between eastern Asia and eastern North America. No previous study has compared the seed biology of closely related disjunct taxa of legumes or of a diaspore-heteromorphic species. Our objective was to compare seed dormancy in two such sister species in the genus Amphicarpaea (Fabaceae). We investigated the ecology and ecophysiology of aerial and subterranean seeds of the amphicarpic species Amphicarpaea edgeworthii from China and compared the results to those published for its sister species A. bracteata from eastern North America. The seed coat of aerial seeds of A. edgeworthii is well developed, whereas the seed coat of subterranean seeds is not. Aerial seeds have combinational dormancy (physical dormancy [PY] + physiological dormancy [PD]) broken by scarification followed by cold stratification or by after-ripening and scarification; whereas subterranean seeds have PD broken by cold stratification. Aerial seeds formed a persistent soil seed bank, and subterranean seeds a transient soil seed bank. Aerial seeds of A. bracteata also have PY+PD and subterranean seeds PD. Subterranean seeds of both species are desiccation intolerant. Dormancy in neither aerial nor subterranean seeds of both species has diverged over geological time. Compared to subterranean seeds, aerial seeds of both species dispersed over longer distances. Seed dispersal ability and degree of dormancy of neither species fits the high-risk/low-risk (H-H/L-L) strategy found in many diaspore-dimorphic species. Rather, both species have an H-L/L-H strategy for these two life history traits. © 2015 Botanical Society of America, Inc.

  17. Actual and potential use of population viability analyses in recovery of plant species listed under the US endangered species act.

    Science.gov (United States)

    Zeigler, Sara L; Che-Castaldo, Judy P; Neel, Maile C

    2013-12-01

    Use of population viability analyses (PVAs) in endangered species recovery planning has been met with both support and criticism. Previous reviews promote use of PVA for setting scientifically based, measurable, and objective recovery criteria and recommend improvements to increase the framework's utility. However, others have questioned the value of PVA models for setting recovery criteria and assert that PVAs are more appropriate for understanding relative trade-offs between alternative management actions. We reviewed 258 final recovery plans for 642 plants listed under the U.S. Endangered Species Act to determine the number of plans that used or recommended PVA in recovery planning. We also reviewed 223 publications that describe plant PVAs to assess how these models were designed and whether those designs reflected previous recommendations for improvement of PVAs. Twenty-four percent of listed species had recovery plans that used or recommended PVA. In publications, the typical model was a matrix population model parameterized with ≤5 years of demographic data that did not consider stochasticity, genetics, density dependence, seed banks, vegetative reproduction, dormancy, threats, or management strategies. Population growth rates for different populations of the same species or for the same population at different points in time were often statistically different or varied by >10%. Therefore, PVAs parameterized with underlying vital rates that vary to this degree may not accurately predict recovery objectives across a species' entire distribution or over longer time scales. We assert that PVA, although an important tool as part of an adaptive-management program, can help to determine quantitative recovery criteria only if more long-term data sets that capture spatiotemporal variability in vital rates become available. Lacking this, there is a strong need for viable and comprehensive methods for determining quantitative, science-based recovery criteria for

  18. Chronic lack of breeding by Galápagos Blue-footed Boobies and associated population decline

    Directory of Open Access Journals (Sweden)

    David Anchundia

    2014-06-01

    Full Text Available A survey of Blue-footed Boobies (Sula nebouxii excisa throughout the taxon's range in Galápagos, Ecuador found ~6400 adults, compared to a rough estimate of 20,000 in the 1960s. Few pairs bred in 2011-2013 and almost no birds in juvenile plumage were seen. Long-term data suggest that poor breeding began in 1998. Lack of recruitment over this period would mean that the current population is mostly elderly and experiencing senescent decline in performance. Anthropogenic effects such as introduced predators are unlikely to explain this decline because islands with and without such factors exhibited the same low breeding. The poor reproduction seems to be linked to diet. Previous work indicated that sardine and herring (Clupeidae supported successful breeding, but these fish were mostly absent from the diet during this study, except in the central part of Galápagos, where most breeding attempts during this study occurred. Elsewhere in the eastern Pacific sardine abundance has decreased dramatically by natural processes in the last 15 years, as part of a well-documented and apparently natural cycle. This cyclic change in abundance provides a possible explanation for the recent demographic changes in Blue-footed Boobies in Galápagos. Whether natural or anthropogenic in origin, the implications of senescent decline in breeding ability and survival are dramatic for this genetically distinct icon of biodiversity and ecotourism.

  19. Cryptic fitness advantage: diploids invade haploid populations despite lacking any apparent advantage as measured by standard fitness assays.

    Directory of Open Access Journals (Sweden)

    Aleeza C Gerstein

    Full Text Available Ploidy varies tremendously within and between species, yet the factors that influence when or why ploidy variants are adaptive remains poorly understood. Our previous work found that diploid individuals repeatedly arose within ten replicate haploid populations of Saccharomyces cerevisiae, and in each case we witnessed diploid takeover within ~1800 asexual generations of batch culture evolution in the lab. The character that allowed diploids to rise in frequency within haploid populations remains unknown. Here we present a number of experiments conducted with the goal to determine what this trait (or traits might have been. Experiments were conducted both by sampling a small number of colonies from the stocks frozen every two weeks (~ 93 generations during the original experiment, as well through sampling a larger number of colonies at the two time points where polymorphism for ploidy was most prevalent. Surprisingly, none of our fitness component measures (lag phase, growth rate, biomass production indicated an advantage to diploidy. Similarly, competition assays against a common competitor and direct competition between haploid and diploid colonies isolated from the same time point failed to indicate a diploid advantage. Furthermore, we uncovered a tremendous amount of trait variation among colonies of the same ploidy level. Only late-appearing diploids showed a competitive advantage over haploids, indicating that the fitness advantage that allowed eventual takeover was not diploidy per se but an attribute of a subset of diploid lineages. Nevertheless, the initial rise in diploids to intermediate frequency cannot be explained by any of the fitness measures used; we suggest that the resolution to this mystery is negative frequency-dependent selection, which is ignored in the standard fitness measures used.

  20. Genetic studies of medfly populations and related species

    International Nuclear Information System (INIS)

    Gasperi, G.; Malacrida, A.R.; Baruffi, L.; Torti, C.; Gomulski, L.; Milani, R.; Guglielmino, C.R.

    1997-01-01

    Multilocus enzyme electrophoresis (MLEE) and random amplified polymorphic DNA were used to detect genetic markers in Ceratitis capitata. The authors employed both types of markers (1) to study the genome organization of the medfly, (2) to determine the level of intraspecific genetic diversity, and (3) to understand the evolution of the geographical populations. Sterility and high mutation rates in interstrain crosses were observed in C. capitata, reminiscent of hybrid dysgenesis in Drosophila, and may represent the activation of mobile elements, useful for medfly transformation. The biochemical, genetic and molecular characterization of the enzyme alcohol dehydrogenase clarified the peculiarity of this selectable system, compared with that of Drosophila, and revealed a surprisingly high sequence variability in medfly populations. The phylogenetic relationships between C. capitata and other Tephritidae species of economic importance were analysed by the MLEE approach. (author)

  1. A review of the key genetic tools to assist imperiled species conservation: analyzing West Indian manatee populations

    Science.gov (United States)

    Bonde, Robert K.; McGuire, Peter M.; Hunter, Margaret E.

    2012-01-01

    Managers faced with decisions on threatened and endangered wildlife populations often are lacking detailed information about the species of concern. Integration of genetic applications will provide management teams with a better ability to assess and monitor recovery efforts on imperiled species. The field of molecular biology continues to progress rapidly and many tools are currently available. Presently, little guidance is available to assist researchers and managers with the appropriate selection of genetic tools to study the status of wild manatee populations. We discuss several genetic tools currently employed in the application of conservation genetics, and address the utility of using these tools to determine population status to aid in conservation efforts. As an example, special emphasis is focused on the endangered West Indian manatee (Order Sirenia). All four extant species of sirenians are imperiled throughout their range, predominately due to anthropogenic sources; therefore, the need for genetic information on their population status is direly needed.

  2. Population and species differences in treeline tree species germination in response to climate change

    Science.gov (United States)

    Kueppers, L. M.; Faist, A.; Castanha, C.

    2009-12-01

    The ability of plant species to recruit within and beyond their current geographic ranges in response to climate warming may be constrained by population differences in response. A number of studies have highlighted the degree to which genotype and environment are strongly linked in forest trees (i.e., provenances), but few studies have examined whether these local adaptations are at all predictive of population or species response to change. We report the results of lab germination experiments using high and low elevation populations of both limber pine (Pinus flexilis) and Engelmann spruce (Picea engelmannii), which are important treeline species in the Rocky Mountains. Seeds collected in 2008 were germinated under two different temperature regimes (ambient and +5°C) and two different moisture regimes, and followed for 17 weeks. For both species and source elevations, warmer temperatures advanced the timing of emergence by up to 20 days, whereas the effects of moisture were less consistent. At harvest, high elevation limber pine had less root and shoot biomass, and a slightly lower root:shoot ratio, under the +5°C treatment, whereas low elevation limber pine seedling mass was not sensitive to temperature. Whether these differences persist under field conditions will be tested in a field experiment now established at Niwot Ridge, CO. The ability to accurately predict tree seedling recruitment and ultimately shifts in treeline position with climate change will improve our ability to model changes in surface albedo, water cycling and carbon cycling, all of which can generate feedbacks to regional and global climate.

  3. POPULATION SYNCHRONY WITHIN AND AMONG LEPIDOPTERA SPECIES IN RELATION TO WEATHER, PHYLOGENY, AND LARVEL PHENOLOGY

    Science.gov (United States)

    1. The population dynamics of native herbivore species in central Appalachian deciduous forests were studied by analysing patterns of synchrony among intra- and interspecific populations and weather. 2. Spatial synchrony of 10 Lepidoptera species and three weather variables (min...

  4. Ultrastructural and molecular characterization of diversity among small araphid diatoms all lacking rimoportulae. I. Five new genera, eight new species.

    Science.gov (United States)

    Li, Chun L; Ashworth, Matt P; Witkowski, Andrzej; Lobban, Christopher S; Zgłobicka, Izabela; Kurzydłowski, Krzysztof J; Qin, Song

    2016-12-01

    Pennate diatoms are important contributors to primary production in freshwater and marine habitats. But the extent of their diversity, ecology, and evolution is still largely unknown. This is particularly evident among the clades of pennate diatoms without raphe slits, whose diversity is likely underestimated due to their small size and features that can be difficult to discern under light microscopy. In this study, we described five new araphid genera with eight new species based on morphological observations (light and electron microscopy) and molecular data (nuclear-encoded small subunit ribosomal RNA and chloroplast-encoded rbcL and psbC): Serratifera varisterna, Hendeyella rhombica, H. dimeregrammopsis, H. lineata, Psammotaenia lanceolata, Castoridens striata, C. hyalina, and Cratericulifera shandongensis. We also transferred Dimeregramma dubium to Hendeyella dubia. Phylogenetic analysis of the molecular data revealed that all the newly established taxa fell into a monophyletic group, with Fragilariforma virescens located at the base. The group was composed by two subclades: one comprising Castoridens, Cratericulifera, and Plagiostriata, and the larger including also the rest of the new genera plus some of the smallest known diatoms, such as Nanofrustulum, Opephora, Pseudostaurosira, Staurosirella, and Staurosira with a high level of support. This study enhances the general knowledge on the phylogeny and biodiversity of a group of small araphid diatoms that have been generally poorly described both by electron microscopy and DNA sequence data. © 2016 Phycological Society of America.

  5. A new species of Silvinichthys (Siluriformes, Trichomycteridae) lacking pelvic fins from mid-elevation localities of the southern Andes, with comments on the genus.

    Science.gov (United States)

    Fernández, L; Sanabria, E A; Quiroga, L B; Vari, R P

    2014-02-01

    Silvinichthys huachi new species, is described from a stream along the lower slope of the Andean Cordillera in the Provincia de San Juan, Argentina. It shares the distinctive modifications characteristic of Silvinichthys, but is distinguished from the four previously described congeners by the combination of a lack of the pelvic fin and the pelvic girdle, details of pigmentation and various meristic and morphometric features. Silvinichthys huachi is apparently endemic to the type locality situated within an arid region of western central Argentina in the Andino Cuyana Province. Major gaps in the range of species of Silvinichthys may indicate that the origin of the genus predates the uplift events that subdivided drainages along the eastern slopes of the Andean Cordillera in west central Argentina. Silvinichthys huachi is hypothesized to be the sister species of Silvinichthys bortayro. © 2014 The Fisheries Society of the British Isles.

  6. Bird population trends are linearly affected by climate change along species thermal ranges

    NARCIS (Netherlands)

    Jiguet, F.; Devictor, V.; Ottvall, R.; Van Turnhout, C.; Van der Jeugd, H.P.; Lindström, Å.

    2010-01-01

    Beyond the effects of temperature increase on local population trends and on species distribution shifts, how populations of a given species are affected by climate change along a species range is still unclear. We tested whether and how species responses to climate change are related to the

  7. Levels of glycine betaine in growing cells and spores of Bacillus species and lack of effect of glycine betaine on dormant spore resistance.

    Science.gov (United States)

    Loshon, Charles A; Wahome, Paul G; Maciejewski, Mark W; Setlow, Peter

    2006-04-01

    Bacteria of various Bacillus species are able to grow in media with very high osmotic strength in part due to the accumulation of low-molecular-weight osmolytes such as glycine betaine (GB). Cells of Bacillus species grown in rich and minimal media contained low levels of GB, but GB levels were 4- to 60-fold higher in cells grown in media with high salt. GB levels in Bacillus subtilis cells grown in minimal medium were increased approximately 7-fold by GB in the medium and 60-fold by GB plus high salt. GB was present in spores of Bacillus species prepared in media with or without high salt but at lower levels than in comparable growing cells. With spores prepared in media with high salt, GB levels were highest in B. subtilis spores and > or =20-fold lower in B. cereus and B. megaterium spores. Although GB levels in B. subtilis spores were elevated 15- to 30-fold by GB plus high salt in sporulation media, GB levels did not affect spore resistance. GB levels were similar in wild-type B. subtilis spores and spores that lacked major small, acid-soluble spore proteins but were much lower in spores that lacked dipicolinic acid.

  8. Species diversity, structure and dynamics of two populations of an endangered species, Magnolia dealbata (Magnoliaceae

    Directory of Open Access Journals (Sweden)

    Lázaro R Sánchez-Velásquez

    2006-09-01

    Full Text Available Little is known about the ecology and demography of the genus Magnolia. Magnolia dealbata Zucc. is an endangered species endemic to Mexico. Two contrasting populations of M. dealbata (one from the grasslands and other from a secondary cloud forest were studied. We asked the following questions: (a Are size structure (diameter at breast height, DBH and infrutescence production significantly different between the two populations? (b What are the populations’ growth rates (λ based on an initial 1987 study? (c Are the associated species diversity indices of these M. dealbata populations significantly different? The results show no significant differences between the population size structure (p=.094; the growth rates of the populations were 0.992 in grassland and 1.053 in secondary cloud forest. The number of infrutescences produced in year 2001 and DBH relationship were significantly linear (p.01 between their slopes. The diversity indices were not significantly different (p>.05, and only 54% of the species were common to both sites. Our study suggests that both populations are relatively stable and that the management history could impact more on the species composition than on the diversity indices. Rev. Biol. Trop. 54 (3: 997-1002. Epub 2006 Sept. 29.La ecología y demografía del género Magnolia han sido poco estudiadas. Magnolia dealbata Zucc. es una especie endémica de México y es considerada en peligro de extinción. Se estudiaron dos poblaciones contrastantes de M. dealbata (una dentro de un pastizal y la otra dentro de vegetación secundaria del bosque mesófilo de montaña -bosque de niebla-. Buscamos respuestas a las siguientes preguntas: (a ¿La estructura de tamaños y la producción de frutos de ambas poblaciones son significativamente diferentes? (b ¿Cuáles son las tasas de crecimiento poblacional (λ, tomando como población inicial un estudio de 1987? (c ¿Son significativamente diferentes los valores de diversidad de

  9. Population ecology of turbot and brill: What can we learn from two rare flatfish species?

    Science.gov (United States)

    van der Hammen, Tessa; Poos, Jan Jaap; van Overzee, Harriët M. J.; Heessen, Henk J. L.; Magnusson, Arni; Rijnsdorp, Adriaan D.

    2013-11-01

    Turbot and brill are widely distributed in the Northeast Atlantic but occur at low abundance. They are ecologically very similar and closely related. The low abundance and the similarities make them particularly interesting to study the population dynamics because it raises the questions how the populations can sustain themselves at low abundances and how turbot and brill avoid strong interspecific competition. Knowledge of both species is hampered by lack of analysed data. The main objective of this study is therefore to increase the knowledge of turbot and brill and in particular to compare the two species in order to address the above questions. Based on biological samples collected in the North Sea, we calculated seasonal von Bertalanffy growth parameters, maturity ogives, monthly gonado-somatic indices (GSI) and condition factors (Fulton's K) and indices of inter- and intraspecific mean crowding and compared the results for turbot and brill. The main differences between the two species were found in their spawning period, with brill having a more protracted spawning period. Brill also showed an earlier peak in their GSI values, suggesting an earlier start of their spawning period. The mean crowding showed that interspecific competition was lower than intraspecific competition. The exploitation pattern was also studied. Turbot and brill are exploited as a bycatch species in the mixed demersal fishery. We found that productivity is highest in areas where the maximum temperature is close to the optimal temperature for growth (16-18 °C) and landings decrease where salinity falls below ~ 5 psu (turbot) and ~ 15 psu (brill). Recent fishing mortality rates of North Sea turbot are around 0.5-0.7, but there is no indication that recruitment is impaired at low levels of spawning stock biomass. We conclude that although both species have similar ecological characteristics, differences may reduce inter-specific competition.

  10. Genetic population structure of the alpine species Rhododendron pseudochrysanthum sensu lato (Ericaceae inferred from chloroplast and nuclear DNA

    Directory of Open Access Journals (Sweden)

    Wang Wei-Kuang

    2011-04-01

    Full Text Available Abstract Background A complex of incipient species with different degrees of morphological or ecological differentiation provides an ideal model for studying species divergence. We examined the phylogeography and the evolutionary history of the Rhododendron pseudochrysanthum s. l. Results Systematic inconsistency was detected between gene genealogies of the cpDNA and nrDNA. Rooted at R. hyperythrum and R. formosana, both trees lacked reciprocal monophyly for all members of the complex. For R. pseudochrysanthum s.l., the spatial distribution of the cpDNA had a noteworthy pattern showing high genetic differentiation (FST = 0.56-0.72 between populations in the Yushan Mountain Range and populations of the other mountain ranges. Conclusion Both incomplete lineage sorting and interspecific hybridization/introgression may have contributed to the lack of monophyly among R. hyperythrum, R. formosana and R. pseudochrysanthum s.l. Independent colonizations, plus low capabilities of seed dispersal in current environments, may have resulted in the genetic differentiation between populations of different mountain ranges. At the population level, the populations of Central, and Sheishan Mountains may have undergone postglacial demographic expansion, while populations of the Yushan Mountain Range are likely to have remained stable ever since the colonization. In contrast, the single population of the Alishan Mountain Range with a fixed cpDNA haplotype may have experienced bottleneck/founder's events.

  11. Genetic population structure of the alpine species Rhododendron pseudochrysanthum sensu lato (Ericaceae) inferred from chloroplast and nuclear DNA.

    Science.gov (United States)

    Huang, Chi-Chun; Hung, Kuo-Hsiang; Hwang, Chi-Chuan; Huang, Jao-Ching; Lin, Hung-Du; Wang, Wei-Kuang; Wu, Pei-Yin; Hsu, Tsai-Wen; Chiang, Tzen-Yuh

    2011-04-19

    A complex of incipient species with different degrees of morphological or ecological differentiation provides an ideal model for studying species divergence. We examined the phylogeography and the evolutionary history of the Rhododendron pseudochrysanthum s. l. Systematic inconsistency was detected between gene genealogies of the cpDNA and nrDNA. Rooted at R. hyperythrum and R. formosana, both trees lacked reciprocal monophyly for all members of the complex. For R. pseudochrysanthum s.l., the spatial distribution of the cpDNA had a noteworthy pattern showing high genetic differentiation (FST=0.56-0.72) between populations in the Yushan Mountain Range and populations of the other mountain ranges. Both incomplete lineage sorting and interspecific hybridization/introgression may have contributed to the lack of monophyly among R. hyperythrum, R. formosana and R. pseudochrysanthum s.l. Independent colonizations, plus low capabilities of seed dispersal in current environments, may have resulted in the genetic differentiation between populations of different mountain ranges. At the population level, the populations of Central, and Sheishan Mountains may have undergone postglacial demographic expansion, while populations of the Yushan Mountain Range are likely to have remained stable ever since the colonization. In contrast, the single population of the Alishan Mountain Range with a fixed cpDNA haplotype may have experienced bottleneck/founder's events.

  12. Lack of association between inguinal hernia and abdominal aortic aneurysm in a population-based male cohort

    DEFF Research Database (Denmark)

    Henriksen, N A; Sorensen, L T; Jørgensen, Lars Nannestad

    2013-01-01

    Previous studies have reported a higher prevalence of inguinal hernia in patients with abdominal aortic aneurysm (AAA). The aim of this study was to explore the association between inguinal hernia and AAA in a large population-based cohort of men who had screening for AAA....

  13. Lack of Ecotypic Differentiation: Plant Response to Elevation, Population Origin, and Wind in the Luquillo Mountains, Puerto Rico

    Science.gov (United States)

    Ned Fetcher; Roberto A. Cordero; Janice Voltzow

    2000-01-01

    How important is ecotypic differentiation along elevational gradients in the tropics? Reciprocal transplants of two shrubs, Clibadium erosum (Asteraceae) and Psychotria berteriana (Rubiaceae), and a palm, Prestoea acuminata var. montana (Palmaceae), were used to test for the effect of environment and population origin on growth and physiology in the Luquillo...

  14. Lack of Support for the Association between Facial Shape and Aggression: A Reappraisal Based on a Worldwide Population Genetics Perspective

    Science.gov (United States)

    Gómez-Valdés, Jorge; Hünemeier, Tábita; Quinto-Sánchez, Mirsha; Paschetta, Carolina; de Azevedo, Soledad; González, Marina F.; Martínez-Abadías, Neus; Esparza, Mireia; Pucciarelli, Héctor M.; Salzano, Francisco M.; Bau, Claiton H. D.; Bortolini, Maria Cátira; González-José, Rolando

    2013-01-01

    Antisocial and criminal behaviors are multifactorial traits whose interpretation relies on multiple disciplines. Since these interpretations may have social, moral and legal implications, a constant review of the evidence is necessary before any scientific claim is considered as truth. A recent study proposed that men with wider faces relative to facial height (fWHR) are more likely to develop unethical behaviour mediated by a psychological sense of power. This research was based on reports suggesting that sexual dimorphism and selection would be responsible for a correlation between fWHR and aggression. Here we show that 4,960 individuals from 94 modern human populations belonging to a vast array of genetic and cultural contexts do not display significant amounts of fWHR sexual dimorphism. Further analyses using populations with associated ethnographical records as well as samples of male prisoners of the Mexico City Federal Penitentiary condemned by crimes of variable level of inter-personal aggression (homicide, robbery, and minor faults) did not show significant evidence, suggesting that populations/individuals with higher levels of bellicosity, aggressive behaviour, or power-mediated behaviour display greater fWHR. Finally, a regression analysis of fWHR on individual's fitness showed no significant correlation between this facial trait and reproductive success. Overall, our results suggest that facial attributes are poor predictors of aggressive behaviour, or at least, that sexual selection was weak enough to leave a signal on patterns of between- and within-sex and population facial variation. PMID:23326328

  15. EXTINCTION RISK OR LACK OF SAMPLING IN A THREATENED SPECIES: GENETIC STRUCTURE AND ENVIRONMENTAL SUITABILITY OF THE NEOTROPICAL FROG PRISTIMANTIS PENELOPUS (ANURA: CRAUGASTORIDAE

    Directory of Open Access Journals (Sweden)

    ADRIANA RESTREPO

    Full Text Available ABSTRACT IUCN Red Lists have been a valuable tool to prioritize conservation plans in endemic neotropical frogs. However, many areas in this region are poorly known in terms of their diversity and endemism. Based on examined museum specimens of the threatened species Pristimantis penelopus we revised its geographic distribution and determined the habitat suitability using niche modeling techniques. Using a mitochondrial fragment of COI gene, we determine the phylogenetic position and the extent of the genetic variation across its distribution in Colombia. We present the first records of P. penelopus for the Cordillera Oriental, the western versant of Cordillera Occidental and the northern portion of the Cauca river basin. Based on the molecular phylogenetic analysis, Pristimantis penelopus belongs to the P. ridens series sensu (Padial et al., 2014. The mean of intraspecific genetic variation is 2.1% and the variation among population ranges between 2.3 and 3.5%. The genetic distance between the western populations and the Magdalena Valley populations suggests a potential phylogeographic break in northwestern Antioquia. We expand the realized distribution by 258 kilometers north, 200 km east and 223 km northwest. Based on our results and according to the IUCN criteria we propose a new category for the species and highlight the need to increase the surveys in poorly known regions to better understand the geographic distribution and conservation status of listed species.

  16. City-Dwellers and Country Folks: Lack of Population Differentiation Along an Urban–Rural Gradient in the Mosquito Culex pipiens (Diptera: Culicidae)

    Science.gov (United States)

    Monaghan, Michael T

    2017-01-01

    Abstract Mosquitoes (Diptera, Culicidae) occur in natural, urban, and peri-urban areas throughout the globe. Although the characteristics of urban and peri-urban habitats differ from those of natural habitats in many ways (e.g., fragmentation, pollution, noise, and light), few studies have examined the population connectivity of mosquitoes in urban areas. To obtain an overview of the species composition, we sampled mosquitoes from 23 sites in and around the city of Berlin, Germany. Of 23 species, five occurred in urban, 10 in peri-urban, and 20 in rural areas. Culex pipiens Linnaeus (Diptera: Culicidae) was the most common species collected (75% of all individuals) and occurred in all habitats. Hence this species was selected to be analysed at 10 microsatellite markers. There was no significant differentiation (FST = 0.016, P = 0.9) or isolation by distance (P = 0.06) among Cx. pipiens populations along an urban–rural gradient. The only significant differences detected were between Cx. pipiens and a laboratory population of Cx. pipiens f. molestus (pairwise FST = 0.114–0.148, P ≤ 0.001 in all comparisons), suggesting that the markers chosen were suitable for the identification of population differentiation. Our results indicate that Cx. pipiens gene flow is widespread within and among urban, peri-urban, and rural areas and that urban habitat does not necessarily impede or enhance gene flow among these populations. PMID:29117382

  17. Lack of association between oxidative stress-related gene polymorphisms and chronic migraine in an Italian population.

    Science.gov (United States)

    Gentile, Giovanna; Negro, Andrea; D'Alonzo, Lidia; Aimati, Laura; Simmaco, Maurizio; Martelletti, Paolo; Borro, Marina

    2015-02-01

    Migraine patients present increased risks of vascular diseases such as high blood pressure, insulin resistance, metabolic syndrome, stroke and coronary heart disease. Oxidative stress (OS) is increasingly being studied in relation to the pathophysiology of migraine, stimulated by the described association with the most frequent migraine comorbidities. Because many of the gene-encoded players of the OS balance are characterized by functional polymorphisms, it is supposed that the individual genomic profile could affect susceptibility to OS and to related pathophysiological conditions. This study aimed to characterize a panel of 10 polymorphisms in 8 OS-related genes in a chronic migraine (CM) population and healthy controls, to recognize a genetic risk in the process of migraine chronification. The sample consisted of 45 healthy women and 96 women diagnosed with CM. No deviations from the Hardy-Weinberg equilibrium were detected, or in the overall population, or in the CM group or in the control group.

  18. Lack of global population genetic differentiation in thearbuscular mycorrhizal fungus Glomus mosseae suggestsa recent range expansion which may have coincided withthe spread of agriculture

    DEFF Research Database (Denmark)

    Rosendahl, Søren; McGee, Peter; Morton, Joseph B

    2009-01-01

    no geographical structure, with identical genotypes found on different continents. Coalescence analyses indicated a recent diversification in the species, and the data could be explained by a recent population expansion in G. mosseae. The results of this study suggest that speciation and the range expansion...... and the resulting sequences analysed for geographical subdivision and estimation of migration between continents. Coalescent analyses estimated divergence and age of mutations. Bayesian coalescent modelling was used to reveal important past population changes in the global population. The sequence data showed...

  19. Population dynamics of Aspergillus section Nigri species on vineyard samples of grapes and raisins

    Science.gov (United States)

    Several species of Aspergillus section Nigri, including potential mycotoxin producers, are common residents of grape vineyards, but the relative population size of individual species throughout the growing season is difficult to determine using traditional isolation and identification methods. Using...

  20. A lack of correlation between brain-derived neurotrophic factor serum level and verbal memory performance in healthy Polish population

    Directory of Open Access Journals (Sweden)

    Monika eWilkosc

    2016-05-01

    Full Text Available Brain derived neurotrophic factor is considered to be connected with memory and learning through the processes of long term synaptic potentiation and synaptic plasticity. The aim of the study was to examine the relationship between precursor BDNF (proBNDF and mature BDNF (mBDNF serum levels and performance on Rey Auditory-Verbal Learning Test (RAVLT in 150 healthy volunteers. In addition, we have verified the relationships between serum concentration of both forms of BDNF and RAVLT with sociodemographic and lifestyle factors. We found no strong evidence for the correlation of proBDNF and mBDNF serum levels with performance on RAVLT in healthy Polish population in early and middle adulthood. We observed the mBDNF serum concentration to be higher in women compared with men. Moreover, we revealed higher mBDNF level to be connected with lower Body Mass Index (BMI. In turn, the results of RAVLT correlated with sociodemographic and lifestyle factors, such as: age, education, gender, BMI and smoking.

  1. On the apllication of single specie dynamic population model | Iguda ...

    African Journals Online (AJOL)

    The Method of mathematical models of Malthus and Verhults were applied on ten years data collected from Magaram Poultry Farm to determine the nature of population growth, population decay or constant ... Keywords: Birth rate, sustainable population, overcrowding, harvesting, independent t-test and one way Anova.

  2. Assessing sociodemographic differences (or lack thereof) in prenatal diagnosis of congenital heart defects: a population-based study

    Science.gov (United States)

    Khoshnood, Babak; Lelong, Nathalie; Andrieu, Thibaut; Houyel, Lucile; Bonnet, Damien; Jouannic, Jean-Marie; Goffinet, François

    2016-01-01

    Objectives Our main objective was to assess sociodemographic differences in the probability of prenatal diagnosis of congenital heart defects (CHD); we also looked at differences in termination of pregnancy for fetal anomaly (TOPFA). Design Prospective cohort observational study. Setting Population-based cohort of CHD (live births, TOPFA, fetal deaths) born to women residing in the Greater Paris area (Paris and its surrounding suburbs, N=317 538 total births). Participants 2867 cases of CHD, including 2348 (82%) live births, 466 (16%) TOPFA and 53 (2%) fetal deaths. Primary and secondary outcome measures Differences in the probability of prenatal diagnosis by maternal occupation, geographic origin and place of residence; differences in the probability of TOPFA. Results 29.1% (95% CI 27.5% to 30.8%) of all CHD were prenatally diagnosed. Probability of prenatal diagnosis was similar by maternal occupation, geographic origin and place of residence. In contrast, there were substantial differences in the probability of TOPFA by maternal geographic origin; differences by maternal occupation and place of residence were generally smaller and not statistically significant. Conclusions Our findings suggest that an appropriate health system organisation aimed at providing universal, reimbursed specialised services to all women can provide comparable access to prenatal diagnosis for all sociodemographic groups. In contrast, we found substantial differences in TOPFA for women of different geographic origins, which may reflect women's preferences that should be respected, but that can nonetheless lead to the situation where families with fewer resources will be disproportionately responsible for care of newborns with more severe forms of CHD. PMID:27009144

  3. Reactive oxygen species and transcript analysis upon excess light treatment in wild-type Arabidopsis thaliana vs a photosensitive mutant lacking zeaxanthin and lutein

    Directory of Open Access Journals (Sweden)

    Roncaglia Enrica

    2011-04-01

    Full Text Available Abstract Background Reactive oxygen species (ROS are unavoidable by-products of oxygenic photosynthesis, causing progressive oxidative damage and ultimately cell death. Despite their destructive activity they are also signalling molecules, priming the acclimatory response to stress stimuli. Results To investigate this role further, we exposed wild type Arabidopsis thaliana plants and the double mutant npq1lut2 to excess light. The mutant does not produce the xanthophylls lutein and zeaxanthin, whose key roles include ROS scavenging and prevention of ROS synthesis. Biochemical analysis revealed that singlet oxygen (1O2 accumulated to higher levels in the mutant while other ROS were unaffected, allowing to define the transcriptomic signature of the acclimatory response mediated by 1O2 which is enhanced by the lack of these xanthophylls species. The group of genes differentially regulated in npq1lut2 is enriched in sequences encoding chloroplast proteins involved in cell protection against the damaging effect of ROS. Among the early fine-tuned components, are proteins involved in tetrapyrrole biosynthesis, chlorophyll catabolism, protein import, folding and turnover, synthesis and membrane insertion of photosynthetic subunits. Up to now, the flu mutant was the only biological system adopted to define the regulation of gene expression by 1O2. In this work, we propose the use of mutants accumulating 1O2 by mechanisms different from those activated in flu to better identify ROS signalling. Conclusions We propose that the lack of zeaxanthin and lutein leads to 1O2 accumulation and this represents a signalling pathway in the early stages of stress acclimation, beside the response to ADP/ATP ratio and to the redox state of both plastoquinone pool. Chloroplasts respond to 1O2 accumulation by undergoing a significant change in composition and function towards a fast acclimatory response. The physiological implications of this signalling specificity are

  4. Bird population trends are linearly affected by climate change along species thermal ranges.

    Science.gov (United States)

    Jiguet, Frédéric; Devictor, Vincent; Ottvall, Richard; Van Turnhout, Chris; Van der Jeugd, Henk; Lindström, Ake

    2010-12-07

    Beyond the effects of temperature increase on local population trends and on species distribution shifts, how populations of a given species are affected by climate change along a species range is still unclear. We tested whether and how species responses to climate change are related to the populations locations within the species thermal range. We compared the average 20 year growth rates of 62 terrestrial breeding birds in three European countries along the latitudinal gradient of the species ranges. After controlling for factors already reported to affect bird population trends (habitat specialization, migration distance and body mass), we found that populations breeding close to the species thermal maximum have lower growth rates than those in other parts of the thermal range, while those breeding close to the species thermal minimum have higher growth rates. These results were maintained even after having controlled for the effect of latitude per se. Therefore, the results cannot solely be explained by latitudinal clines linked to the geographical structure in local spring warming. Indeed, we found that populations are not just responding to changes in temperature at the hottest and coolest parts of the species range, but that they show a linear graded response across their European thermal range. We thus provide insights into how populations respond to climate changes. We suggest that projections of future species distributions, and also management options and conservation assessments, cannot be based on the assumption of a uniform response to climate change across a species range or at range edges only.

  5. Incorporating population viability models into species status assessment and listing decisions under the U.S. Endangered Species Act

    Directory of Open Access Journals (Sweden)

    Conor P. McGowan

    2017-10-01

    Full Text Available Assessment of a species' status is a key part of management decision making for endangered and threatened species under the U.S. Endangered Species Act. Predicting the future state of the species is an essential part of species status assessment, and projection models can play an important role in developing predictions. We built a stochastic simulation model that incorporated parametric and environmental uncertainty to predict the probable future status of the Sonoran desert tortoise in the southwestern United States and North Central Mexico. Sonoran desert tortoise was a Candidate species for listing under the Endangered Species Act, and decision makers wanted to use model predictions in their decision making process. The model accounted for future habitat loss and possible effects of climate change induced droughts to predict future population growth rates, abundances, and quasi-extinction probabilities. Our model predicts that the population will likely decline over the next few decades, but there is very low probability of quasi-extinction less than 75 years into the future. Increases in drought frequency and intensity may increase extinction risk for the species. Our model helped decision makers predict and characterize uncertainty about the future status of the species in their listing decision. We incorporated complex ecological processes (e.g., climate change effects on tortoises in transparent and explicit ways tailored to support decision making processes related to endangered species.

  6. Population genetic structure of coral reef species Plectorhinchus ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-06-03

    Jun 3, 2008 ... 510300 P.R. China. Accepted 24 April, 2008. The population genetic structure and the dispersal ability of Plectorhinchus flavomaculatus from South. China Sea were examined with a 464 bp segment of mtDNA control region. A total of 116 .... θ1 (θ before and after the population growth) and τ (time since.

  7. How Spanish Primary School Students Interpret the Concepts of Population and Species

    Science.gov (United States)

    Jiménez-Tejada, María-Pilar; Sánchez-Monsalve, Cristina; González-García, Francisco

    2013-01-01

    This article presents research concerning the way in which primary school pupils in southern Spain interpret the concepts of population and species. The results show that, for the concept of population, there was an intense anthropocentrism in pupils' responses, while for the concept of species, only animals were considered as living creatures.…

  8. Spatial-temporal population dynamics across species range: from centre to margin

    Science.gov (United States)

    Qinfeng Guo; Mark Taper; Michele Schoenberger; J. Brandle

    2005-01-01

    Understanding the boundaries of species'rangs and the variations in population dynamics from the centre to margin of a species' range is critical. This study simulated spatial-tamporal patterns of birth and death rates and migration across a species' range in different seasons. Our results demonstrated the importance of dispersal and migration in...

  9. Population-specific responses to an invasive species

    Czech Academy of Sciences Publication Activity Database

    Reichard, Martin; Douda, K.; Przybylski, M.; Popa, O. P.; Karbanová, E.; Matasová, K.; Rylková, K.; Polačik, Matej; Blažek, Radim; Smith, Carl

    2015-01-01

    Roč. 282, č. 1812 (2015), s. 167-174, č. článku 20151063. ISSN 0962-8452 R&D Projects: GA ČR GA13-05872S Institutional support: RVO:68081766 Keywords : alien species * Anodonta woodiana * intraspecific variation * glochidia * host–parasite dynamics * symbiosis Subject RIV: EG - Zoology Impact factor: 4.823, year: 2015

  10. Population dynamics and potential yield of three species of giant ...

    African Journals Online (AJOL)

    Of the southern African intertidal and shallow subtidal trochid and turbinid gastropods, Turbo sarmaticus, T. cidaris and Oxystele sinensis, are the most abundant large species, and therefore obvious targets for a winkle fishery. T. sarmaticus is harvested by recreational snorkel divers, and an application has been made for a ...

  11. Sharing the Planet. Population - Consumption - Species. Science and Ethics for a Sustainable and Equitable World

    Energy Technology Data Exchange (ETDEWEB)

    Van der Zwaan, B.; Petersen, A. (eds.)

    2003-11-01

    The world is going through the profound changes of a demographic transition. Population growth is best taken care of when women and men are able to choose freely and responsibly their number of children. The most important aspects are the availability of reliable and safe means and the access women have to knowledge, resources and decision power. General education is a prerequisite. (Groningen Manifesto, statement no. 7). The current international, political, economic and financial order still primarily reflects the claims of international trade. There is a lack of public awareness as to the inescapable limits of the planet's resources and we hardly seem to be moving towards a sustainable and equitable world. The contributors to this volume provide an up-to-date and forceful exposition of this problematique. In the aftermath of the World Summit on Sustainable Development held in Johannesburg, they suggest topical ways to alter the world's course. The keys to reaching a sustainable world, in which the planet is equitably shared among humans and other species, are to consider the impact of our collective actions at longer timescales and to deal head-on with the interconnected issues of population pressure, consumption volume and species loss. The volume displays a multidisciplinary and multicultural approach involving both scientific and ethical arguments. It is of interest to a wide audience of scholars and concerned citizens. With contributions by: Ernst Ulrich von Weizsaecker, Friedrich Schmidt-Bleek, Johan van Klinken, Anne Ehrlich, Sergey Kapitza, Roefie Hueting, Jan van Hooff, Lucas Reijnders, Arthur Petersen, Bob van der Zwaan, Vandana Shiva, Radha Holla, Koo van der Wal, Bas de Gaay Fortman, Atiq Rahman and Jane Goodall.

  12. Commonly rare and rarely common: comparing population abundance of invasive and native aquatic species.

    Science.gov (United States)

    Hansen, Gretchen J A; Vander Zanden, M Jake; Blum, Michael J; Clayton, Murray K; Hain, Ernie F; Hauxwell, Jennifer; Izzo, Marit; Kornis, Matthew S; McIntyre, Peter B; Mikulyuk, Alison; Nilsson, Erika; Olden, Julian D; Papeş, Monica; Sharma, Sapna

    2013-01-01

    Invasive species are leading drivers of environmental change. Their impacts are often linked to their population size, but surprisingly little is known about how frequently they achieve high abundances. A nearly universal pattern in ecology is that species are rare in most locations and abundant in a few, generating right-skewed abundance distributions. Here, we use abundance data from over 24,000 populations of 17 invasive and 104 native aquatic species to test whether invasive species differ from native counterparts in statistical patterns of abundance across multiple sites. Invasive species on average reached significantly higher densities than native species and exhibited significantly higher variance. However, invasive and native species did not differ in terms of coefficient of variation, skewness, or kurtosis. Abundance distributions of all species were highly right skewed (skewness>0), meaning both invasive and native species occurred at low densities in most locations where they were present. The average abundance of invasive and native species was 6% and 2%, respectively, of the maximum abundance observed within a taxonomic group. The biological significance of the differences between invasive and native species depends on species-specific relationships between abundance and impact. Recognition of cross-site heterogeneity in population densities brings a new dimension to invasive species management, and may help to refine optimal prevention, containment, control, and eradication strategies.

  13. Excessive Sleep and Lack of Sleep Are Associated With Slips and Falls in the Adult Korean Population: A Population-Based Cross-Sectional Study.

    Science.gov (United States)

    Kim, So Young; Kim, Sung-Gyun; Sim, Songyong; Park, Bumjung; Choi, Hyo Geun

    2016-01-01

    Few studies have evaluated the impacts of excessive sleep duration on falls. This study investigated the associations between sleep duration and falls among Korean adults in a wide range of age groups while adjusting for numerous confounding factors. Data collected from study participants ranging in age from 19 to 109 years old were analyzed from the 2013 Korean Community Health Survey (KCHS). Sleep duration was divided into 5 groups: ≤5, 6, 7, 8, and ≥9  hours per day. The relations between sleep duration and falls (≥1 time or ≥2 times per year) were analyzed using simple and multiple logistic regression analyses with complex sampling. Age, sex, days of vigorous or moderate physical activity, income, education, alcohol use, smoking, stress, obesity, hypertension, diabetes mellitus, hyperlipidemia, stroke, angina or myocardial infarction, arthritis, and asthma were controlled for as confounding factors. Associations between sleep duration and falls were analyzed in 19 to 40, 41 to 60, and 61+ year age groups. Furthermore, the relations between sleep duration and indoor versus outdoor falls were analyzed. Both ≤6 and ≥8  hours of sleep per day were significantly associated with an increased incidence of falls (≥1 time and ≥2 times per year) in the overall adult population (P sleep durations of ≤5 and ≥9  hours were significantly associated with an increased incidence of falls (≥1 time a year) in each age group. Six hours of sleep was not significantly associated with falls (≥2 times per year) in the 61+ year age group, and 8 and 9  hours of sleep were not significantly associated with falls (≥2 times a year) in the 19 to 40 year age group. This study demonstrated that long as well as short sleep durations are associated with an increased incidence of falls. However, these relations were not evident in elderly populations with short sleep durations or in young adults with long sleep durations.

  14. Introduction beyond a species range: a relationship between population origin, adaptive potential and plant performance.

    Science.gov (United States)

    Volis, S; Ormanbekova, D; Yermekbayev, K; Song, M; Shulgina, I

    2014-09-01

    The adaptive potential of a population defines its importance for species survival in changing environmental conditions such as global climate change. Very few empirical studies have examined adaptive potential across species' ranges, namely, of edge vs core populations, and we are unaware of a study that has tested adaptive potential (namely, variation in adaptive traits) and measured performance of such populations in conditions not currently experienced by the species but expected in the future. Here we report the results of a Triticum dicoccoides population study that employed transplant experiments and analysis of quantitative trait variation. Two populations at the opposite edges of the species range (1) were locally adapted; (2) had lower adaptive potential (inferred from the extent of genetic quantitative trait variation) than the two core populations; and (3) were outperformed by the plants from the core population in the novel environment. The fact that plants from the species arid edge performed worse than plants from the more mesic core in extreme drought conditions beyond the present climatic envelope of the species implies that usage of peripheral populations for conservation purposes must be based on intensive sampling of among-population variation.

  15. Variation in Body Shape across Species and Populations in a Radiation of Diaptomid Copepods.

    Directory of Open Access Journals (Sweden)

    Stephen Hausch

    Full Text Available Inter and intra-population variation in morphological traits, such as body size and shape, provides important insights into the ecological importance of individual natural populations. The radiation of Diaptomid species (~400 species has apparently produced little morphological differentiation other than those in secondary sexual characteristics, suggesting sexual, rather than ecological, selection has driven speciation. This evolutionary history suggests that species, and conspecific populations, would be ecologically redundant but recent work found contrasting ecosystem effects among both species and populations. This study provides the first quantification of shape variation among species, populations, and/or sexes (beyond taxonomic illustrations and body size measurements to gain insight into the ecological differentiation of Diaptomids. Here we quantify the shape of five Diaptomid species (family Diaptomidae from four populations each, using morphometric landmarks on the prosome, urosome, and antennae. We partition morphological variation among species, populations, and sexes, and test for phenotype-by-environment correlations to reveal possible functional consequences of shape variation. We found that intraspecific variation was 18-35% as large as interspecific variation across all measured traits. Interspecific variation in body size and relative antennae length, the two traits showing significant sexual dimorphism, were correlated with lake size and geographic location suggesting some niche differentiation between species. Observed relationships between intraspecific morphological variation and the environment suggest that divergent selection in contrasting lakes might contribute to shape differences among local populations, but confirming this requires further analyses. Our results show that although Diaptomid species differ in their reproductive traits, they also differ in other morphological traits that might indicate ecological

  16. Malthusian Catastrophe: Species Extinction Caused By Oversized Population

    OpenAIRE

    Pan, Xubin

    2017-01-01

    There is one pseudo-extinction debt and four occurring conditions for real extinction debt. Since small and oversized populations have a high extinction risk, Pan threshold (upper limit) was calculated for Verhulst-Pear logistic growth model and logistic model with the Allee effect, an important parameter corresponding to Allee threshold (lower limit).

  17. Population genetic structure of coral reef species Plectorhinchus ...

    African Journals Online (AJOL)

    The population genetic structure and the dispersal ability of Plectorhinchus flavomaculatus from South China Sea were examined with a 464 bp segment of mtDNA control region. A total of 116 individuals were collected from 12 coral reefs in Xisha, Zhongsha and Nansha archipelagos and 22 haplotypes were obtained.

  18. Effect of population size on prospect of species survival

    Czech Academy of Sciences Publication Activity Database

    Münzbergová, Zuzana

    2006-01-01

    Roč. 41, - (2006), s. 137-150 ISSN 1211-9520 R&D Projects: GA AV ČR KJB6111303 Institutional research plan: CEZ:AV0Z60050516 Keywords : population * size * survival Subject RIV: EF - Botanics Impact factor: 1.196, year: 2006

  19. on the apllication of single specie dynamic population model 306

    African Journals Online (AJOL)

    pc

    used to compare the predicted values and observed values in order to find out whether there is significant difference between the observed and predicted values using these two models. Keywords: Birth rate, sustainable population, overcrowding, harvesting, independent t-test and ..... 95% confidence interval of the.

  20. 76 FR 28715 - Endangered and Threatened Species: Designation of a Nonessential Experimental Population for...

    Science.gov (United States)

    2011-05-18

    ... Experimental Population for Middle Columbia River Steelhead Above the Pelton Round Butte Hydroelectric Project... central Oregon, as a nonessential experimental population (NEP) under the Endangered Species Act (ESA... as an experimental population the MCR steelhead currently being reintroduced to the upper Deschutes...

  1. 78 FR 2893 - Endangered and Threatened Species: Designation of a Nonessential Experimental Population for...

    Science.gov (United States)

    2013-01-15

    ... Experimental Population for Middle Columbia River Steelhead above the Pelton Round Butte Hydroelectric Project... Counties, Oregon, and designate them as a nonessential experimental population (NEP) under the Endangered... (Secretary) to authorize the release of an experimental population of an endangered or threatened species...

  2. 76 FR 77465 - Endangered and Threatened Species; Proposed Threatened Status for Distinct Population Segments of...

    Science.gov (United States)

    2011-12-13

    ... Population Segments of the Bearded Seal AGENCY: National Marine Fisheries Service (NMFS), National Oceanic... population segments (DPS) of the bearded seal (Erignathus barbatus) as threatened species under the... posed to this population by the projected habitat changes. Extension of Final Listing Determination The...

  3. 76 FR 14883 - Endangered and Threatened Species; Proposed Threatened Status for Distinct Population Segments of...

    Science.gov (United States)

    2011-03-18

    ...-XZ58 Endangered and Threatened Species; Proposed Threatened Status for Distinct Population Segments of..., published a proposed rule to list the Beringia and Okhotsk Distinct Population Segments (DPSs) of the... published a proposed rule to list the Beringia and Okhotsk Distinct Population Segments (DPSs) of the...

  4. A minimum stochastic model evaluating the interplay between population density and drift for species coexistence

    Science.gov (United States)

    Guariento, Rafael Dettogni; Caliman, Adriano

    2017-02-01

    Despite the general acknowledgment of the role of niche and stochastic process in community dynamics, the role of species relative abundances according to both perspectives may have different effects regarding coexistence patterns. In this study, we explore a minimum probabilistic stochastic model to determine the relationship of populations relative and total abundances with species chances to outcompete each other and their persistence in time (i.e., unstable coexistence). Our model is focused on the effects drift (i.e., random sampling of recruitment) under different scenarios of selection (i.e., fitness differences between species). Our results show that taking into account the stochasticity in demographic properties and conservation of individuals in closed communities (zero-sum assumption), initial population abundance can strongly influence species chances to outcompete each other, despite fitness inequalities between populations, and also, influence the period of coexistence of these species in a particular time interval. Systems carrying capacity can have an important role in species coexistence by exacerbating fitness inequalities and affecting the size of the period of coexistence. Overall, the simple stochastic formulation used in this study demonstrated that populations initial abundances could act as an equalizing mechanism, reducing fitness inequalities, which can favor species coexistence and even make less fitted species to be more likely to outcompete better-fitted species, and thus to dominate ecological communities in the absence of niche mechanisms. Although our model is restricted to a pair of interacting species, and overall conclusions are already predicted by the Neutral Theory of Biodiversity, our main objective was to derive a model that can explicitly show the functional relationship between population densities and community mono-dominance odds. Overall, our study provides a straightforward understanding of how a stochastic process (i

  5. The Bifurcation and Control of a Single-Species Fish Population Logistic Model with the Invasion of Alien Species

    Directory of Open Access Journals (Sweden)

    Yi Zhang

    2014-01-01

    Full Text Available The objective of this paper is to study systematically the bifurcation and control of a single-species fish population logistic model with the invasion of alien species based on the theory of singular system and bifurcation. It regards Spartina anglica as an invasive species, which invades the fisheries and aquaculture. Firstly, the stabilities of equilibria in this model are discussed. Moreover, the sufficient conditions for existence of the trans-critical bifurcation and the singularity induced bifurcation are obtained. Secondly, the state feedback controller is designed to eliminate the unexpected singularity induced bifurcation by combining harvested effort with the purification capacity. It obviously inhibits the switch of population and makes the system stable. Finally, the numerical simulation is proposed to show the practical significance of the bifurcation and control from the biological point of view.

  6. Prioritizing Avian Species for Their Risk of Population-Level Consequences from Wind Energy Development.

    Science.gov (United States)

    Beston, Julie A; Diffendorfer, Jay E; Loss, Scott R; Johnson, Douglas H

    2016-01-01

    Recent growth in the wind energy industry has increased concerns about its impacts on wildlife populations. Direct impacts of wind energy include bird and bat collisions with turbines whereas indirect impacts include changes in wildlife habitat and behavior. Although many species may withstand these effects, species that are long-lived with low rates of reproduction, have specialized habitat preferences, or are attracted to turbines may be more prone to declines in population abundance. We developed a prioritization system to identify the avian species most likely to experience population declines from wind facilities based on their current conservation status and their expected risk from turbines. We developed 3 metrics of turbine risk that incorporate data on collision fatalities at wind facilities, population size, life history, species' distributions relative to turbine locations, number of suitable habitat types, and species' conservation status. We calculated at least 1 measure of turbine risk for 428 avian species that breed in the United States. We then simulated 100,000 random sets of cutoff criteria (i.e., the metric values used to assign species to different priority categories) for each turbine risk metric and for conservation status. For each set of criteria, we assigned each species a priority score and calculated the average priority score across all sets of criteria. Our prioritization system highlights both species that could potentially experience population decline caused by wind energy and species at low risk of population decline. For instance, several birds of prey, such as the long-eared owl, ferruginous hawk, Swainson's hawk, and golden eagle, were at relatively high risk of population decline across a wide variety of cutoff values, whereas many passerines were at relatively low risk of decline. This prioritization system is a first step that will help researchers, conservationists, managers, and industry target future study and management

  7. Molecular markers for genetic diversity, gene flow and genetic population structure of freshwater mussel species

    Directory of Open Access Journals (Sweden)

    AB Choupina

    Full Text Available Freshwater mussel species are in global decline. Anthropogenic changes of river channels and the decrease of autochthonous fish population, the natural hosts of mussels larval stages (glochidia, are the main causes. Therefore, the conservation of mussel species depends not only on habitat conservation, but also on the availability of the fish host. In Portugal, information concerning most of the mussel species is remarkably scarce. One of the most known species, Unio pictorum is also in decline however, in the basins of the rivers Tua and Sabor (Northeast of Portugal, there is some indication of relatively large populations. The aforementioned rivers can be extremely important for this species conservation not only in Portugal, but also in the remaining Iberian Peninsula. Thus, it is important to obtain data concerning Unio pictorum bioecology (distribution, habitat requirements, population structure, genetic variability, reproductive cycle and recruitment rates, as well as the genetic variability and structure of the population. Concomitantly, information concerning fish population structure, the importance of the different fish species as “glochidia” hosts and their appropriate density to allow effective mussel recruitment, will also be assessed. The achieved data is crucial to obtain information to develop effective management measures in order to promote the conservation of this bivalve species, the conservation of autochthonous fish populations, and consequently the integrity of the river habitats.

  8. Range Expansion and Population Dynamics of an Invasive Species: The Eurasian Collared-Dove (Streptopelia decaocto)

    OpenAIRE

    Scheidt, Spencer N.; Hurlbert, Allen H.

    2014-01-01

    Invasive species offer ecologists the opportunity to study the factors governing species distributions and population growth. The Eurasian Collared-Dove (Streptopelia decaocto) serves as a model organism for invasive spread because of the wealth of abundance records and the recent development of the invasion. We tested whether a set of environmental variables were related to the carrying capacities and growth rates of individual populations by modeling the growth trajectories of individual po...

  9. Population structure of Annona crassiflora: an endemic plant species of the Brazilian Cerrado.

    Science.gov (United States)

    Gwinner, R; Setotaw, T A; Rodrigues, F A; França, D V C; da Silveira, F A; Pio, L A S; Pasqual, M

    2016-12-23

    Habitat fragmentation has numerous consequences, particularly to endemic species, and has a negative impact on the genetic diversity of neglected species, leading to genetic drift. Annona crassiflora Mart. is a species that is endemic to Brazil, and its incidence in the Cerrado biome has decreased. The identification and characterization of its remaining diversity is necessary for its conservation. Our aim was to study the population structure of A. crassiflora populations from different Cerrado regions in Minas Gerais State, Brazil (Corinto, Curvelo, Carmo da Mata, Boa Esperança, and Paraguaçu) using inter-simple sequence repeat (ISSR) markers and DNA content. Nuclear DNA content was estimated by flow cytometry using 10 individuals from each population. ISSR markers were used for genotyping accessions in order to study their genetic diversity and population structures. We found considerable genetic variation among populations, with the highest variability observed in the Curvelo population. There was a significant positive correlation between DNA content and latitude (r = 0.46, P = 0. 0003). A Bayesian-based cluster analysis grouped the populations into three clusters, which followed their geographical origins. There was some level of genetic diversity and differentiation among the populations, suggesting the need for a conservation plan for this species. The ISSR markers and DNA content analysis were effective in studying the genetic diversity and population structure of A. crassiflora.

  10. Wild Plant Species with Extremely Small Populations Require Conservation and Reintroduction in China

    Science.gov (United States)

    Hai Ren; Qianmei Zhang; Hongfang Lu; Hongxiao Liu; Qinfeng Guo; Jun Wang; Shuguang Jian; Hai’ou Bao

    2012-01-01

    China is exceptionally rich in biodiversity, with more than 30000 vascular plant species that include many endemic genera, species of ancient origin, and cultivated plants (Yang et al. 2005). Because of rapid economic development, population growth, pollution, and continuing resource exploitation, China’s plant diversity faces severe threats. According to the Chinese...

  11. Species Profile: Least Tern (Sterna antillarum), Interior Population, on Military Installations in the Southeastern United States

    National Research Council Canada - National Science Library

    Mitchell, Wilma

    1998-01-01

    .... Although few southeastern U.S. military installations are located on rivers within the range of the interior population, installations with suitable habitat in other sections of the United States should benefit from this profile. This document is one of a series of Species Profiles being developed for threatened, endangered, and sensitive species inhabiting southeastern United States plant communities.

  12. Genetic population structure of Fusarium graminearum species complex in Korean cereals

    Science.gov (United States)

    Small grain cereals are frequently contaminated with toxigenic Fusarium species. Members of the Fusarium graminearum species complex (FGSC) are known as a head blight pathogens and mycotoxin producers. In order to characterize the FGSC populations associated with cereals in Korea, barley, corn, maiz...

  13. Prioritizing avian species for their risk of population-level consequences from wind energy development

    Science.gov (United States)

    Beston, Julie A.; Diffendorfer, James E.; Loss, Scott; Johnson, Douglas H.

    2016-01-01

    Recent growth in the wind energy industry has increased concerns about its impacts on wildlife populations. Direct impacts of wind energy include bird and bat collisions with turbines whereas indirect impacts include changes in wildlife habitat and behavior. Although many species may withstand these effects, species that are long-lived with low rates of reproduction, have specialized habitat preferences, or are attracted to turbines may be more prone to declines in population abundance. We developed a prioritization system to identify the avian species most likely to experience population declines from wind facilities based on their current conservation status and their expected risk from turbines. We developed 3 metrics of turbine risk that incorporate data on collision fatalities at wind facilities, population size, life history, species’ distributions relative to turbine locations, number of suitable habitat types, and species’ conservation status. We calculated at least 1 measure of turbine risk for 428 avian species that breed in the United States. We then simulated 100,000 random sets of cutoff criteria (i.e., the metric values used to assign species to different priority categories) for each turbine risk metric and for conservation status. For each set of criteria, we assigned each species a priority score and calculated the average priority score across all sets of criteria. Our prioritization system highlights both species that could potentially experience population decline caused by wind energy and species at low risk of population decline. For instance, several birds of prey, such as the long-eared owl, ferruginous hawk, Swainson’s hawk, and golden eagle, were at relatively high risk of population decline across a wide variety of cutoff values, whereas many passerines were at relatively low risk of decline. This prioritization system is a first step that will help researchers, conservationists, managers, and industry target future study and

  14. Characterization of Aspergillus section Nigri species populations in vineyard soil using droplet digital PCR.

    Science.gov (United States)

    Palumbo, J D; O'Keeffe, T L; Fidelibus, M W

    2016-12-01

    Identification of populations of Aspergillus section Nigri species in environmental samples using traditional methods is laborious and impractical for large numbers of samples. We developed species-specific primers and probes for quantitative droplet digital PCR (ddPCR) to improve sample throughput and simultaneously detect multiple species in each sample. The ddPCR method was used to distinguish Aspergillus niger, Aspergillus welwitschiae, Aspergillus tubingensis and Aspergillus carbonarius in mixed samples of total DNA. Relative abundance of each species measured by ddPCR agreed with input ratios of template DNAs. Soil samples were collected at six time points over two growing seasons from two raisin vineyards in Fresno County, California. Aspergillus section Nigri strains were detected in these soils in the range of 10 2 -10 5  CFU g -1 . Relative abundance of each species varied widely among samples, but in 52 of 60 samples, A. niger was the most abundant species, ranging from 38 to 88% of the total population. In combination with total plate counts, this ddPCR method provides a high-throughput method for describing population dynamics of important potential mycotoxin-producing species in environmental samples. This is the first study to demonstrate the utility of ddPCR as a means to quantify species of Aspergillus section Nigri in soil. This method eliminates the need for isolation and sequence identification of individual fungal isolates, and allows for greater throughput in measuring relative population sizes of important (i.e. mycotoxigenic) Aspergillus species within a population of morphologically indistinguishable species. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

  15. Evaluating population connectivity for species of conservation concern in the American Great Plains

    Science.gov (United States)

    Samuel A. Cushman; Erin L. Landguth; Curtis H. Flather

    2013-01-01

    Habitat loss and fragmentation are widely recognized as among the most important threats to global biodiversity. New analytical approaches are providing an improved ability to predict the effects of landscape change on population connectivity at vast spatial extents. This paper presents an analysis of population connectivity for three species of conservation concern [...

  16. 75 FR 53272 - Endangered and Threatened Species; Initiation of 5-Year Review of the Eastern Distinct Population...

    Science.gov (United States)

    2010-08-31

    ... and Threatened Species; Initiation of 5-Year Review of the Eastern Distinct Population Segment of the... Distinct Population Segment (DPS) of the Steller Sea Lion (Eumetopias jubatus) under the Endangered Species... Distinct Population Segment (DPS) of the Steller Sea Lion (Eumetopias jubatus) under the Endangered Species...

  17. Conservation state of populations of rare plant species in highly transformed meadow steppes of Southern Opillya

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    I. I. Dmytrash-Vatseba

    2016-09-01

    Full Text Available Degradation of natural habitats causes rapid extinction of rare plant populations. The diversity of rare plant species in the meadow steppes of Southern Opillya (Western Ukraine depends strongly on patch area, pasture digression of vegetation and a variety of eco-coenotical conditions. The main threats for the rare components of the meadow steppe flora are reduction of habitat and overgrazing. Spatial connections between sites are unable to support a constant rare plant population. The analysis of the composition of rare plant meadow-steppe species indicated that habitats with similar rare species composition usually have similar parameters of area, stages of pasture digression and eco-coenotical conditions. Spatial connectivity of patches does not ensure species similarity of rare components of the flora. Rare plant species were grouped according to their preferences for habitat , area and condition. In small patches subject to any stage of pasture digression grow populations of Adonis vernalis L., Pulsatilla patens (L. Mill., P. grandis Wender., Stipa capillata L., S. рennata L., Chamaecytisus blockianus (Pawł. Klásková etc. On the contrary, populations of other species (Carlina onopordifolia Besser. ex Szafer., Kuecz. et Pawł., Adenophora liliifolia (L. Ledeb. ex A. DC., Crambe tataria Sebeók, Euphorbia volhynica Besser ex Racib., Stipa tirsa Stev. etc. prefer large habitats, not changed by pasture digression. Prevention of reduction of rare species diversity requires preservation (also extension of patch area and regulation of grazing intensity.

  18. Monitoring of fish species in the Lamone river: distribution and morphometric measures of the populations

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    Riccardo Bozzi

    2010-01-01

    Full Text Available Fish samplings were carried out monthly from spring to autumn during 2008, on the Lamone river and the Campigno stream by an electrofishing, in order to verify the presence of fish populations and the most common species represented. Barb, Barbus plebejus, Blageon, Leuciscus muticellus, Chub, Leuciscus cephalus, South European Nase, Chondrostoma genei were identified. A small population of Brown trout, Salmo trutta fario was also recognized. Barb is the most represented species in all the sites. The samplings highlight that Lamone river presented conditions suitable to fully guarantee the life of the fish populations.

  19. Very Low Population Structure in a Highly Mobile and Wide-Ranging Endangered Bird Species.

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    Lynna Kvistad

    Full Text Available The loss of biodiversity following fragmentation and degradation of habitat is a major issue in conservation biology. As competition for resources increases following habitat loss and fragmentation, severe population declines may occur even in common, highly mobile species; such demographic decline may cause changes within the population structure of the species. The regent honeyeater, Anthochaera phrygia, is a highly nomadic woodland bird once common in its native southeast Australia. It has experienced a sharp decline in abundance since the late 1970s, following clearing of large areas of its preferred habitat, box-ironbark woodland, within the last 200 years. A captive breeding program has been established as part of efforts to restore this species. This study used genetic data to examine the range-wide population structure of regent honeyeaters, including spatial structure, its change through time, sex differences in philopatry and mobility, and genetic differences between the captive and wild populations. There was low genetic differentiation between birds captured in different geographic areas. Despite the recent demographic decline, low spatial structure appears to have some temporal consistency. Both sexes appear to be highly mobile, and there does not seem to be significant genetic differentiation between the captive and wild populations. We conclude that management efforts for survival of this species, including habitat protection, restoration, and release of captive-bred birds into the wild, can treat the species as effectively a single genetic population.

  20. Local Climate Heterogeneity Shapes Population Genetic Structure of Two Undifferentiated Insular Scutellaria Species.

    Science.gov (United States)

    Hsiung, Huan-Yi; Huang, Bing-Hong; Chang, Jui-Tse; Huang, Yao-Moan; Huang, Chih-Wei; Liao, Pei-Chun

    2017-01-01

    Spatial climate heterogeneity may not only affect adaptive gene frequencies but could also indirectly shape the genetic structure of neutral loci by impacting demographic dynamics. In this study, the effect of local climate on population genetic variation was tested in two phylogenetically close Scutellaria species in Taiwan. Scutellaria taipeiensis , which was originally assumed to be an endemic species of Taiwan Island, is shown to be part of the widespread species S. barbata based on the overlapping ranges of genetic variation and climatic niches as well as their morphological similarity. Rejection of the scenario of "early divergence with secondary contact" and the support for multiple origins of populations of S. taipeiensis from S. barbata provide strong evolutionary evidence for a taxonomic revision of the species combination. Further tests of a climatic effect on genetic variation were conducted. Regression analyses show nonlinear correlations among any pair of geographic, climatic, and genetic distances. However, significantly, the bioclimatic variables that represent the precipitation from late summer to early autumn explain roughly 13% of the genetic variation of our sampled populations. These results indicate that spatial differences of precipitation in the typhoon season may influence the regeneration rate and colonization rate of local populations. The periodic typhoon episodes explain the significant but nonlinear influence of climatic variables on population genetic differentiation. Although, the climatic difference does not lead to species divergence, the local climate variability indeed impacts the spatial genetic distribution at the population level.

  1. Population Genetic Structure and Species Status of Asiatic Toads (Bufo gargarizans) in Western China.

    Science.gov (United States)

    Wen, Guannan; Yang, Weizhao; Fu, Jinzhong

    2015-10-01

    We investigated the population genetic structure of Asiatic toads (Bufo gargarizans) from the mountains of western China to determine their species status, using genotypic data of ten microsatellite DNA loci and DNA sequences from one mitochondrial gene. A total of 197 samples from eight sites were examined, which cover a large range of elevations (559-3457 m), as well as all three traditionally defined species (or subspecies). AMOVA did not reveal any particularly large among-groups structure, whether the sites were grouped by drainage, elevation, region, or species (subspecies). Individual assignment tests placed all samples into two genetic clusters, which largely corresponded to their geographic locations. An isolation-by-distance pattern was also detected when an outlier population (site 3) was excluded. Furthermore, a mitochondrial gene tree revealed deep divergence among haplotypes, sometimes within the same site. The clade patterns were partially associated with geographic distribution but had no resemblance to the traditional 2- or 3-species classification. Overall, these toad populations harbor a large amount of genetic diversity and have very high population differentiation, but taken together the evidence suggests that all populations belong to a single species. Our results are consistent with most previous molecular studies, and we recommend using Bufo gargarizans to represent all Asiatic toad populations from western China without subspecies division.

  2. Murine bone marrow Lin⁻Sca⁻1⁺CD45⁻ very small embryonic-like (VSEL cells are heterogeneous population lacking Oct-4A expression.

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    Krzysztof Szade

    Full Text Available Murine very small embryonic-like (VSEL cells, defined by the Lin(-Sca-1(+CD45(- phenotype and small size, were described as pluripotent cells and proposed to be the most primitive hematopoietic precursors in adult bone marrow. Although their isolation and potential application rely entirely on flow cytometry, the immunophenotype of VSELs has not been extensively characterized. Our aim was to analyze the possible heterogeneity of Lin(-Sca(+CD45(- population and investigate the extent to which VSELs characteristics may overlap with that of hematopoietic stem cells (HSCs or endothelial progenitor cells (EPCs. The study evidenced that murine Lin(-Sca-1(+CD45(- population was heterogeneous in terms of c-Kit and KDR expression. Accordingly, the c-Kit(+KDR(-, c-Kit(-KDR(+, and c-Kit(-KDR(- subpopulations could be distinguished, while c-Kit(+KDR(+ events were very rare. The c-Kit(+KDR(- subset contained almost solely small cells, meeting the size criterion of VSELs, in contrast to relatively bigger c-Kit(-KDR(+ cells. The c-Kit(-KDR(-FSC(low subset was highly enriched in Annexin V-positive, apoptotic cells, hence omitted from further analysis. Importantly, using qRT-PCR, we evidenced lack of Oct-4A and Oct-4B mRNA expression either in whole adult murine bone marrow or in the sorted of Lin(-Sca-1(+CD45(-FSC(low population, even by single-cell qRT-PCR. We also found that the Lin(-Sca-1(+CD45(-c-Kit(+ subset did not exhibit hematopoietic potential in a single cell-derived colony in vitro assay, although it comprised the Sca-1(+c-Kit(+Lin(- (SKL CD34(-CD45(-CD105(+ cells, expressing particular HSC markers. Co-culture of Lin(-Sca-1(+CD45(-FSC(low with OP9 cells did not induce hematopoietic potential. Further investigation revealed that SKL CD45(-CD105(+ subset consisted of early apoptotic cells with fragmented chromatin, and could be contaminated with nuclei expelled from erythroblasts. Concluding, murine bone marrow Lin(-Sca-1(+CD45(-FSC(low cells are

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

    Directory of Open Access Journals (Sweden)

    Forchhammer Mads C

    2009-06-01

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

  4. Genetic structure and phenotypic variation in wild populations of the medicinal tetraploid species Bromelia antiacantha (Bromeliaceae).

    Science.gov (United States)

    Zanella, Camila Martini; Bruxel, Manuela; Paggi, Gecele Matos; Goetze, Márcia; Buttow, Miriam Valli; Cidade, Fernanda Witt; Bered, Fernanda

    2011-09-01

    The patterns of genetic structure in plant populations are mainly related to the species life history and breeding system, and knowledge of these patterns is necessary for the management, use, and conservation of biological diversity. Polyploidy is considered an important mode of evolution in plants, but few studies have evaluated genetic structure of polyploid populations. We studied the patterns of genetic structure and morphological variation of Bromelia antiacantha (Bromeliaceae) populations, a polyploid terrestrial species. • Microsatellite markers and morphological analyses were used to explore patterns of genetic and morphological diversity in wild populations of B. antiacantha. • The results of our simple-sequence repeat analyses supported that B. antiacantha is a polyploid species. The inbreeding coefficients were high and significant in all populations (F(IS) = 0.431), indicating homozygote excess. Bromelia antiacantha showed high levels of genetic differentiation among populations (F(ST) = 0.224) and therefore was highly structured. High morphological variation was observed in fruit phenotypic traits in the populations studied. • The levels of genetic diversity and the pattern of the population's structure may be related to the low recruitment of seeds, clonal reproduction, and the population's colonization history. The genetic and morphological variability displayed in this study are important issues in planning the conservation and exploitation of this resource in a sustainable way.

  5. High prices for rare species can drive large populations extinct: the anthropogenic Allee effect revisited.

    Science.gov (United States)

    Holden, Matthew H; McDonald-Madden, Eve

    2017-09-21

    Consumer demand for plant and animal products threatens many populations with extinction. The anthropogenic Allee effect (AAE) proposes that such extinctions can be caused by prices for wildlife products increasing with species rarity. This price-rarity relationship creates financial incentives to extract the last remaining individuals of a population, despite higher search and harvest costs. The AAE has become a standard approach for conceptualizing the threat of economic markets on endangered species. Despite its potential importance for conservation, AAE theory is based on a simple graphical model with limited analysis of possible population trajectories. By specifying a general class of functions for price-rarity relationships, we show that the classic theory can understate the risk of species extinction. AAE theory proposes that only populations below a critical Allee threshold will go extinct due to increasing price-rarity relationships. Our analysis shows that this threshold can be much higher than the original theory suggests, depending on initial harvest effort. More alarmingly, even species with population sizes above this Allee threshold, for which AAE predicts persistence, can be destined to extinction. Introducing even a minimum price for harvested individuals, close to zero, can cause large populations to cross the classic anthropogenic Allee threshold on a trajectory towards extinction. These results suggest that traditional AAE theory may give a false sense of security when managing large harvested populations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Genetic variation in horizontally transmitted fungal endophytes of pine needles reveals population structure in cryptic species.

    Science.gov (United States)

    Oono, Ryoko; Lutzoni, François; Arnold, A Elizabeth; Kaye, Laurel; U'Ren, Jana M; May, Georgiana; Carbone, Ignazio

    2014-08-01

    • Fungal endophytes comprise one of the most ubiquitous groups of plant symbionts, inhabiting healthy leaves and stems of all major lineages of plants. Together, they comprise immense species richness, but little is known about the fundamental processes that generate their diversity. Exploration of their population structure is needed, especially with regard to geographic distributions and host affiliations.• We take a multilocus approach to examine genetic variation within and among populations of Lophodermium australe, an endophytic fungus commonly associated with healthy foliage of pines in the southeastern United States. Sampling focused on two pine species ranging from montane to coastal regions of North Carolina and Virginia.• Our sampling revealed two genetically distinct groups within Lophodermium australe. Our analysis detected less than one migrant per generation between them, indicating that they are distinct species. The species comprising the majority of isolates (major species) demonstrated a panmictic structure, whereas the species comprising the minority of isolates (cryptic species) demonstrated isolation by distance. Distantly related pine species hosted the same Lophodermium species, and host species did not influence genetic structure.• We present the first evidence for isolation by distance in a foliar fungal endophyte that is horizontally transmitted. Cryptic species may be common among microbial symbionts and are important to delimit when exploring their genetic structure and microevolutionary processes. The hyperdiversity of endophytic fungi may be explained in part by cryptic species without apparent ecological and morphological differences as well as genetic diversification within rare fungal species across large spatial scales. © 2014 Botanical Society of America, Inc.

  7. Clutch size in populations and species of cnemidophorines (Squamata: Teiidae on the eastern coast of Brazil

    Directory of Open Access Journals (Sweden)

    VANDERLAINE A. MENEZES

    2014-06-01

    Full Text Available We analyzed some reproductive aspects of 16 coastal populations, belonging to five lizard species (A. ocellifera, A. abaetensis, A. nativo, A. littoralis and C. lacertoides from different restinga habitats along the eastern coast of Brazil. This study aimed to evaluate to what extent the reproductive aspects vary geographically and among species. For each female, we recorded the number of vitellogenic follicles, size and color of the largest follicle, presence and size of corpora lutea, and number and size of oviductal eggs. Clutch size of almost all coastal populations/species of Ameivula had little variation and most clutches were composed of two eggs. There was a significant relationship between female size and the mean clutch size when females from different species were pooled. Mean egg volume, among species, varied from 420 to 655 mm3. Relative clutch mass varied from 0.129 to 0.159 and did not differ significantly among species. We concluded that the five coastal species studied (four bisexuals and one parthenogenetic had similar reproductive characteristics. Most of them presented multiple clutches, low clutch size and low relative clutch mass, similar to other species in the genus and to unisexual and bisexual species of the Teiidae family.

  8. Population dynamics along a primary succession gradient: do alpine species fit into demographic succession theory?

    Science.gov (United States)

    Marcante, Silvia; Winkler, Eckart; Erschbamer, Brigitta

    2009-05-01

    Understanding processes and mechanisms governing changes in plant species along primary successions has been of major importance in ecology. However, to date hardly any studies have focused on the complete life cycle of species along a successional gradient, comparing pioneer, early and late-successional species. In this study it is hypothesized that pioneer species should initially have a population growth rate, lambda, greater than one with high fecundity rates, and declining growth rates when they are replaced by late-successional species. Populations of late-successional species should also start, at the mid-successional stage (when pioneer species are declining), with growth rates greater than one and arrive at rates equal to one at the late successional stage, mainly due to higher survival rates that allow these species to persist for a long time. The demography of pioneer- (Saxifraga aizoides), early (Artemisia genipi) and late-successional species (Anthyllis vulneraria ssp. alpicola) was investigated together with that of a ubiquitous species (Poa alpina) along the Rotmoos glacier foreland (2300-2400 m a.s.l., Central Alps, Austria) over 3 years. A matrix modelling approach was used to compare the main demographic parameters. Elasticity values were plotted in a demographic triangle using fecundity, individual growth and survival as vital rates contributing to the population growth rates. The results largely confirmed the predictions for population growth rates during succession. However, high survival rates of larger adults characterized all species, regardless of where they were growing along the succession. At the pioneer site, high mortality rates of seedlings, plantlets and young individuals were recorded. Fecundity was found to be of minor relevance everywhere, but it was nevertheless sufficient to increase or maintain the population sizes. Demographically, all the species over all sites behaved like late-successional or climax species in secondary

  9. Persistence of historical population structure in an endangered species despite near-complete biome conversion in California's San Joaquin Desert.

    Science.gov (United States)

    Richmond, Jonathan Q; Wood, Dustin A; Westphal, Michael F; Vandergast, Amy G; Leaché, Adam D; Saslaw, Lawrence R; Butterfield, H Scott; Fisher, Robert N

    2017-07-01

    Genomic responses to habitat conversion can be rapid, providing wildlife managers with time-limited opportunities to enact recovery efforts that use population connectivity information that reflects predisturbance landscapes. Despite near-complete biome conversion, such opportunities may still exist for the endemic fauna and flora of California's San Joaquin Desert, but comprehensive genetic data sets are lacking for nearly all species in the region. To fill this knowledge gap, we studied the rangewide population structure of the endangered blunt-nosed leopard lizard Gambelia sila, a San Joaquin Desert endemic, using restriction site-associated DNA (RAD), microsatellite and mtDNA data to test whether admixture patterns and estimates of effective migration surfaces (EEMS) can identify land areas with high population connectivity prior to the conversion of native xeric habitats. Clustering and phylogenetic analyses indicate a recent shared history between numerous isolated populations and EEMS reveals latent signals of corridors and barriers to gene flow over areas now replaced by agriculture and urbanization. Conflicting histories between the mtDNA and nuclear genomes are consistent with hybridization with the sister species G. wislizenii, raising important questions about where legal protection should end at the southern range limit of G. sila. Comparative analysis of different data sets also adds to a growing list of advantages in using RAD loci for genetic studies of rare species. We demonstrate how the results of this work can serve as an evolutionary guidance tool for managing endemic, arid-adapted taxa in one of the world's most compromised landscapes. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  10. Selection for life-history traits to maximize population growth in an invasive marine species

    DEFF Research Database (Denmark)

    Jaspers, Cornelia; Marty, Lise; Kiørboe, Thomas

    2018-01-01

    Species establishing outside their natural range, negatively impacting local ecosystems, are of increasing global concern. They often display life-history features characteristic for r-selected populations with fast growth and high reproduction rates to achieve positive population growth rates (r......) in invaded habitats. Here, we demonstrate substantially earlier maturation at a 2 orders of magnitude lower body mass at first reproduction in invasive compared to native populations of the comb jelly Mnemiopsis leidyi. Empirical results are corroborated by a theoretical model for competing life...... populations is an underappreciated determinant of invasiveness, acting as substrate upon which selection can act during the invasion process....

  11. Variations in Host Preference among and within Populations of Heterodera trifolii and Related Species.

    Science.gov (United States)

    Wang, S; Riggs, R D

    1999-12-01

    Seven populations of Heterodera trifolii from Arkansas, Kentucky, Pennsylvania, and Australia plus 3 or 4 single-cyst isolates (SCI) from each population were tested for reproduction on seven species of plants to compare the host preferences among and within populations. Common lespedeza, Kummerowia striata cv. Kobe, was a good host for all populations and isolates. Therefore, a plant was considered to be a host if the number of females produced on it was 10% or more of the number on Kobe. All seven populations reproduced on Trifolium repens and T. pratense. None reproduced on Beta vulgaris or Glycine max. One single-cyst isolate from the Australian population produced a few females on T. pratense. The Australian population maintained on carnation, Dianthus caryophyllus, produced females on carnation but not on curly dock, Rumex crispus. However, its subpopulation maintained on T. repens produced females on R. crispus but not on carnation. Four of the other six populations produced females on R. crispus, and four produced females on carnation. Differences in host range were observed among seven of the mother populations and their SCI, and among isolates within each population. Five host range patterns were found in populations and SCI of H. trifolii. Significant quantitative differences occurred among populations in the numbers of females on most hosts, between isolates and their original populations, and among isolates from the same population. SCI selected from white clover produced fewer females on a series of test hosts and had host ranges the same as or narrower than those of the original populations. However, SCI selected from Kobe lespedeza had more females on some hosts and had host ranges the same as or wider than those of the original populations. The host ranges of all populations and SCI of H. trifolii were different from those of populations and SCI of race 3 of H. glycines and H. lespedezae.

  12. Variation in mycorrhizal associations with tulasnelloid fungi among populations of five Dactylorhiza species.

    Science.gov (United States)

    Jacquemyn, Hans; Deja, Agnieszka; De hert, Koen; Cachapa Bailarote, Bruno; Lievens, Bart

    2012-01-01

    Orchid species rely on mycorrhizal symbioses with fungi to complete their life cycle. Although there is mounting evidence that orchids can associate with several fungi from different clades or families, less is known about the actual geographic distribution of these fungi and how they are distributed across different orchid species within a genus. We investigated among-population variation in mycorrhizal associations in five species of the genus Dactylorhiza (D. fuchsii, D. incarnata, D. maculata, D. majalis and D. praetermissa) using culture-independent detection and identification techniques enabling simultaneous detection of multiple fungi in a single individual. Mycorrhizal specificity, determined as the number of fungal operational taxonomic units (OTUs), and phylogenetic diversity of fungi were compared between species, whereas discriminant analysis was used to compare mycorrhizal spectra across populations and species. Based on a 95% cut-off value in internal transcribed spacer (ITS) sequence similarity, a total of ten OTUs was identified belonging to three different clades within the Tulasnellaceae. Most OTUs were found in two or more Dactylorhiza species, and some of them were common and widespread, occurring in more than 50% of all sampled populations. Each orchid species associated with at least five different OTUs, whereas most individuals also associated with two or more fungal OTUs at the same time. Phylogenetic diversity, corrected for species richness, was not significantly different between species, confirming the generality of the observed orchid mycorrhizal associations. We found that the investigated species of the genus Dactylorhiza associated with a wide range of fungal OTUs from the Tulasnellaceae, some of which were widespread and common. These findings challenge the idea that orchid rarity is related to mycorrhizal specificity and fungal distribution.

  13. Reliable DNA barcoding performance proved for species and island populations of comoran squamate reptiles.

    Directory of Open Access Journals (Sweden)

    Oliver Hawlitschek

    Full Text Available In the past decade, DNA barcoding became increasingly common as a method for species identification in biodiversity inventories and related studies. However, mainly due to technical obstacles, squamate reptiles have been the target of few barcoding studies. In this article, we present the results of a DNA barcoding study of squamates of the Comoros archipelago, a poorly studied group of oceanic islands close to and mostly colonized from Madagascar. The barcoding dataset presented here includes 27 of the 29 currently recognized squamate species of the Comoros, including 17 of the 18 endemic species. Some species considered endemic to the Comoros according to current taxonomy were found to cluster with non-Comoran lineages, probably due to poorly resolved taxonomy. All other species for which more than one barcode was obtained corresponded to distinct clusters useful for species identification by barcoding. In most species, even island populations could be distinguished using barcoding. Two cryptic species were identified using the DNA barcoding approach. The obtained barcoding topology, a Bayesian tree based on COI sequences of 5 genera, was compared with available multigene topologies, and in 3 cases, major incongruences between the two topologies became evident. Three of the multigene studies were initiated after initial screening of a preliminary version of the barcoding dataset presented here. We conclude that in the case of the squamates of the Comoros Islands, DNA barcoding has proven a very useful and efficient way of detecting isolated populations and promising starting points for subsequent research.

  14. Discriminating Multi-Species Populations in Biofilms with Peptide Nucleic Acid Fluorescence In Situ Hybridization (PNA FISH)

    Science.gov (United States)

    Almeida, Carina; Azevedo, Nuno F.; Santos, Sílvio; Keevil, Charles W.; Vieira, Maria J.

    2011-01-01

    Background Our current understanding of biofilms indicates that these structures are typically composed of many different microbial species. However, the lack of reliable techniques for the discrimination of each population has meant that studies focusing on multi-species biofilms are scarce and typically generate qualitative rather than quantitative data. Methodology/Principal Findings We employ peptide nucleic acid fluorescence in situ hybridization (PNA FISH) methods to quantify and visualize mixed biofilm populations. As a case study, we present the characterization of Salmonella enterica/Listeria monocytogenes/Escherichia coli single, dual and tri-species biofilms in seven different support materials. Ex-situ, we were able to monitor quantitatively the populations of ∼56 mixed species biofilms up to 48 h, regardless of the support material. In situ, a correct quantification remained more elusive, but a qualitative understanding of biofilm structure and composition is clearly possible by confocal laser scanning microscopy (CLSM) at least up to 192 h. Combining the data obtained from PNA FISH/CLSM with data from other established techniques and from calculated microbial parameters, we were able to develop a model for this tri-species biofilm. The higher growth rate and exopolymer production ability of E. coli probably led this microorganism to outcompete the other two [average cell numbers (cells/cm2) for 48 h biofilm: E. coli 2,1×108 (±2,4×107); L. monocytogenes 6,8×107 (±9,4×106); and S. enterica 1,4×106 (±4,1×105)]. This overgrowth was confirmed by CSLM, with two well-defined layers being easily identified: the top one with E. coli, and the bottom one with mixed regions of L. monocytogenes and S. enterica. Significance While PNA FISH has been described previously for the qualitative study of biofilm populations, the present investigation demonstrates that it can also be used for the accurate quantification and spatial distribution of species in

  15. Plant species with extremely small populations (PSESP in China: A seed and spore biology perspective

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    Ellie Merrett Wade

    2016-10-01

    Full Text Available Approximately one fifth of the world's plants are at risk of extinction. Of these, a significant number exist as populations of few individuals, with limited distribution ranges and under enormous pressure due to habitat destruction. In China, these most-at-risk species are described as ‘plant species with extremely small populations’ (PSESP. Implementing conservation action for such listed species is urgent. Storing seeds is one of the main means of ex situ conservation for flowering plants. Spore storage could provide a simple and economical method for fern ex situ conservation. Seed and spore germination in nature is a critical step in species regeneration and thus in situ conservation. But what is known about the seed and spore biology (storage and germination of at-risk species? We have used China's PSESP (the first group listing as a case study to understand the gaps in knowledge on propagule biology of threatened plant species. We found that whilst germination information is available for 28 species (23% of PSESP, storage characteristics are only known for 8% of PSESP (10 species. Moreover, we estimate that 60% of the listed species may require cryopreservation for long-term storage. We conclude that comparative biology studies are urgently needed on the world's most threatened taxa so that conservation action can progress beyond species listing.

  16. Range expansion and population dynamics of an invasive species: the Eurasian Collared-Dove (Streptopelia decaocto.

    Directory of Open Access Journals (Sweden)

    Spencer N Scheidt

    Full Text Available Invasive species offer ecologists the opportunity to study the factors governing species distributions and population growth. The Eurasian Collared-Dove (Streptopelia decaocto serves as a model organism for invasive spread because of the wealth of abundance records and the recent development of the invasion. We tested whether a set of environmental variables were related to the carrying capacities and growth rates of individual populations by modeling the growth trajectories of individual populations of the Collared-Dove using Breeding Bird Survey (BBS and Christmas Bird Count (CBC data. Depending on the fit of our growth models, carrying capacity and growth rate parameters were extracted and modeled using historical, geographical, land cover and climatic predictors. Model averaging and individual variable importance weights were used to assess the strength of these predictors. The specific variables with the greatest support in our models differed between data sets, which may be the result of temporal and spatial differences between the BBS and CBC. However, our results indicate that both carrying capacity and population growth rates are related to developed land cover and temperature, while growth rates may also be influenced by dispersal patterns along the invasion front. Model averaged multivariate models explained 35-48% and 41-46% of the variation in carrying capacities and population growth rates, respectively. Our results suggest that widespread species invasions can be evaluated within a predictable population ecology framework. Land cover and climate both have important effects on population growth rates and carrying capacities of Collared-Dove populations. Efforts to model aspects of population growth of this invasive species were more successful than attempts to model static abundance patterns, pointing to a potentially fruitful avenue for the development of improved invasive distribution models.

  17. Population genetics data help to guide the conservation of palm species with small population sizes and fragmented habitats in Madagascar

    Directory of Open Access Journals (Sweden)

    Lauren M. Gardiner

    2017-05-01

    Full Text Available Background The need to incorporate genetic data into conservation management decisions is increasingly recognised. However, many published studies represent a ‘gold standard’ of sampling, techniques, and analyses. Such rigour is often not possible with limited funding and resourcing available for developing plans for the increasing number of threatened species requiring conservation management. Two endemic palm species of the Itremo Massif in central Madagascar, Dypsis ambositrae and D. decipiens, are known to be threatened with extinction and conservation management for these species is a priority for the newly created protected area in the region. Methods The genetic diversity of these two species was studied using the relatively low-cost and rapid AFLP technique. DNA fragments generated using three primer combinations were analysed for 20 and 50 individuals of the two species, respectively, from across their ranges. Results Genetic diversity was relatively low for both species. The two sites where the highly restricted D. ambositrae grows were found to be genetically distinct (although overall heterozygosity was low. Despite having a much wider distribution and relatively large population, D. decipiens did not show clear geographical nor genetic groupings and had similarly low genetic heterozygosity to D. ambositrae. Discussion and Recommendations With so few individuals remaining in the wild and two genetically distinct subpopulations, it is recommended that both sites of D. ambositrae are conserved and that seed are collected from both for ex situ conservation and potential future reintroduction. It may be less important to focus resources on conserving or collecting ex situ material from all sites where D. decipiens is found, as the genetic diversity represented by each subpopulation is limited and increasing sampling may not protect significantly higher levels of genetic diversity. This study provides data that inform and support

  18. Sjögren's syndrome: managed care data from a large United States population highlight real-world health care burden and lack of treatment options.

    Science.gov (United States)

    Birt, Julie A; Tan, YingMeei; Mozaffarian, Neelufar

    2017-01-01

    To better understand the real-world characteristics and costs of Sjögren's syndrome (SS). Analysing the MarketScan Commercial Claims database from Jan. 1, 2006 to Dec. 31, 2011, we identified 10,414 patients ≥18 years old newly diagnosed with SS. Patient characteristics, drugs (commonly used for SS), resource utilisation, and medical costs were evaluated for 12 months pre- and post-diagnosis. Mean age was 55 years; 90% were female. At diagnosis, SS patients were most often seen by rheumatologists (39%) or internists (14.2%); the most common concurrent autoimmune conditions were rheumatoid arthritis (17.9%) and systemic lupus erythematosus (14.6%). Other common comorbidities were hypertension (37.6%), osteoarthritis (31.4%), and hyperlipidaemia/dyslipidaemia (30.3%). Post diagnosis of SS, claims for myocardial infarction and coronary artery bypass graft doubled. Medications of interest prescribed post-diagnosis were eye/mouth drugs (32.2%) and synthetic immunosuppressants (32.1%). Biologic drugs were prescribed to a minority (TNF inhibitors, ~5.0%; non-TNF inhibitors, 1%). Of note, prescriptions for all systemic immunotherapies (synthetic and biologic) were significantly lower in the subgroup without concurrent autoimmune disease, and 15.1% of the overall population had no SS-related prescriptions. Post diagnosis, total medical resource utilisation and total medical costs increased (1.2 and 1.4-fold, respectively). In this retrospective, real-world analysis, medical claims in the first year after SS diagnosis revealed that cardiovascular (CV) events increased and all-cause healthcare costs grew by 40%. Pharmacologic management consisted primarily of low potency immunomodulation and symptomatic treatments. Systemic disease-modifying therapies were used mostly in patients who had another concurrent autoimmune disease, suggesting a lack of treatment options for SS.

  19. Genetic Diversity and Population Structure of Two Tomato Species from the Galapagos Islands.

    Science.gov (United States)

    Pailles, Yveline; Ho, Shwen; Pires, Inês S; Tester, Mark; Negrão, Sónia; Schmöckel, Sandra M

    2017-01-01

    Endemic flora of the Galapagos Islands has adapted to thrive in harsh environmental conditions. The wild tomato species from the Galapagos Islands, Solanum cheesmaniae and S. galapagense , are tolerant to various stresses, and can be crossed with cultivated tomato. However, information about genetic diversity and relationships within and between populations is necessary to use these resources efficiently in plant breeding. In this study, we analyzed 3,974 polymorphic SNP markers, obtained through the genotyping-by-sequencing technique, DArTseq, to elucidate the genetic diversity and population structure of 67 accessions of Galapagos tomatoes (compared to two S. lycopersicum varieties and one S. pimpinellifolium accession). Two clustering methods, Principal Component Analysis and STRUCTURE, showed clear distinction between the two species and a subdivision in the S. cheesmaniae group corresponding to geographical origin and age of the islands. High genetic variation among the accessions within each species was suggested by the AMOVA. High diversity in the S. cheesmaniae group and its correlation with the islands of origin were also suggested. This indicates a possible influence of the movement of the islands, from west to east, on the gene flow. Additionally, the absence of S. galapagense populations in the eastern islands points to the species divergence occurring after the eastern islands became isolated. Based on these results, it can be concluded that the population structure of the Galapagos tomatoes collection partially explains the evolutionary history of both species, knowledge that facilitates exploitation of their genetic potential for the identification of novel alleles contributing to stress tolerance.

  20. Genetic Diversity and Population Structure of Two Tomato Species from the Galapagos Islands

    KAUST Repository

    Pailles, Yveline

    2017-02-15

    Endemic flora of the Galapagos Islands has adapted to thrive in harsh environmental conditions. The wild tomato species from the Galapagos Islands, Solanum cheesmaniae and S. galapagense, are tolerant to various stresses, and can be crossed with cultivated tomato. However, information about genetic diversity and relationships within and between populations is necessary to use these resources efficiently in plant breeding. In this study, we analyzed 3,974 polymorphic SNP markers, obtained through the genotyping-by-sequencing technique, DArTseq, to elucidate the genetic diversity and population structure of 67 accessions of Galapagos tomatoes (compared to two S. lycopersicum varieties and one S. pimpinellifolium accession). Two clustering methods, Principal Component Analysis and STRUCTURE, showed clear distinction between the two species and a subdivision in the S. cheesmaniae group corresponding to geographical origin and age of the islands. High genetic variation among the accessions within each species was suggested by the AMOVA. High diversity in the S. cheesmaniae group and its correlation with the islands of origin were also suggested. This indicates a possible influence of the movement of the islands, from west to east, on the gene flow. Additionally, the absence of S. galapagense populations in the eastern islands points to the species divergence occurring after the eastern islands became isolated. Based on these results, it can be concluded that the population structure of the Galapagos tomatoes collection partially explains the evolutionary history of both species, knowledge that facilitates exploitation of their genetic potential for the identification of novel alleles contributing to stress tolerance.

  1. Integrating bioclimate with population models to improve forecasts of species extinctions under climate change

    Science.gov (United States)

    Brook, Barry W.; Akçakaya, H. Resit; Keith, David A.; Mace, Georgina M.; Pearson, Richard G.; Araújo, Miguel B.

    2009-01-01

    Climate change is already affecting species worldwide, yet existing methods of risk assessment have not considered interactions between demography and climate and their simultaneous effect on habitat distribution and population viability. To address this issue, an international workshop was held at the University of Adelaide in Australia, 25–29 May 2009, bringing leading species distribution and population modellers together with plant ecologists. Building on two previous workshops in the UK and Spain, the participants aimed to develop methodological standards and case studies for integrating bioclimatic and metapopulation models, to provide more realistic forecasts of population change, habitat fragmentation and extinction risk under climate change. The discussions and case studies focused on several challenges, including spatial and temporal scale contingencies, choice of predictive climate, land use, soil type and topographic variables, procedures for ensemble forecasting of both global climate and bioclimate models and developing demographic structures that are realistic and species-specific and yet allow generalizations of traits that make species vulnerable to climate change. The goal is to provide general guidelines for assessing the Red-List status of large numbers of species potentially at risk, owing to the interactions of climate change with other threats such as habitat destruction, overexploitation and invasive species. PMID:19625300

  2. Integrating bioclimate with population models to improve forecasts of species extinctions under climate change.

    Science.gov (United States)

    Brook, Barry W; Akçakaya, H Resit; Keith, David A; Mace, Georgina M; Pearson, Richard G; Araújo, Miguel B

    2009-12-23

    Climate change is already affecting species worldwide, yet existing methods of risk assessment have not considered interactions between demography and climate and their simultaneous effect on habitat distribution and population viability. To address this issue, an international workshop was held at the University of Adelaide in Australia, 25-29 May 2009, bringing leading species distribution and population modellers together with plant ecologists. Building on two previous workshops in the UK and Spain, the participants aimed to develop methodological standards and case studies for integrating bioclimatic and metapopulation models, to provide more realistic forecasts of population change, habitat fragmentation and extinction risk under climate change. The discussions and case studies focused on several challenges, including spatial and temporal scale contingencies, choice of predictive climate, land use, soil type and topographic variables, procedures for ensemble forecasting of both global climate and bioclimate models and developing demographic structures that are realistic and species-specific and yet allow generalizations of traits that make species vulnerable to climate change. The goal is to provide general guidelines for assessing the Red-List status of large numbers of species potentially at risk, owing to the interactions of climate change with other threats such as habitat destruction, overexploitation and invasive species.

  3. Effectiveness of protected areas for representing species and populations of terrestrial mammals in Costa Rica.

    Science.gov (United States)

    González-Maya, José F; Víquez-R, Luis R; Belant, Jerrold L; Ceballos, Gerardo

    2015-01-01

    Costa Rica has one of the greatest percentages (26%) of protected land in the world. The National Protected Areas System (NPAS) of Costa Rica was established in 1976 and currently includes >190 protected areas within seven different protection categories. The effectiveness of the NPAS to represent species, populations, and areas with high species richness has not been properly evaluated. Such evaluations are fundamental to understand what is necessary to strengthen the NPAS and better protect biodiversity. We present a novel assessment of NPAS effectiveness in protecting mammal species. We compiled the geographical ranges of all terrestrial Costa Rican mammals then determined species lists for all protected areas and the estimated proportion of each species' geographic range protected. We also classified mammal species according to their conservation status using the IUCN Red List of Threatened Species. We found almost complete representation of mammal species (98.5%) in protected areas, but low relative coverage (28.3% on average) of their geographic ranges in Costa Rica and 25% of the species were classified as underprotected according to a priori representation targets. Interestingly, many species-rich areas are not protected, and at least 43% of cells covering the entire country are not included in protected areas. Though protected areas in Costa Rica represent species richness well, strategic planning for future protected areas to improve species complementarity and range protection is necessary. Our results can help to define sites where new protected areas can have a greater impact on mammal conservation, both in terms of species richness and range protection.

  4. Plant population differentiation and climate change: responses of grassland species along an elevational gradient.

    Science.gov (United States)

    Frei, Esther R; Ghazoul, Jaboury; Matter, Philippe; Heggli, Martin; Pluess, Andrea R

    2014-02-01

    Mountain ecosystems are particularly susceptible to climate change. Characterizing intraspecific variation of alpine plants along elevational gradients is crucial for estimating their vulnerability to predicted changes. Environmental conditions vary with elevation, which might influence plastic responses and affect selection pressures that lead to local adaptation. Thus, local adaptation and phenotypic plasticity among low and high elevation plant populations in response to climate, soil and other factors associated with elevational gradients might underlie different responses of these populations to climate warming. Using a transplant experiment along an elevational gradient, we investigated reproductive phenology, growth and reproduction of the nutrient-poor grassland species Ranunculus bulbosus, Trifolium montanum and Briza media. Seeds were collected from low and high elevation source populations across the Swiss Alps and grown in nine common gardens at three different elevations with two different soil depths. Despite genetic differentiation in some traits, the results revealed no indication of local adaptation to the elevation of population origin. Reproductive phenology was advanced at lower elevation in low and high elevation populations of all three species. Growth and reproduction of T. montanum and B. media were hardly affected by garden elevation and soil depth. In R. bulbosus, however, growth decreased and reproductive investment increased at higher elevation. Furthermore, soil depth influenced growth and reproduction of low elevation R. bulbosus populations. We found no evidence for local adaptation to elevation of origin and hardly any differences in the responses of low and high elevation populations. However, the consistent advanced reproductive phenology observed in all three species shows that they have the potential to plastically respond to environmental variation. We conclude that populations might not be forced to migrate to higher elevations

  5. Evidence of ecotypic differentiation between populations of the tree species Parapiptadenia rigida due to flooding

    OpenAIRE

    Silva, D. C. G.; Carvalho, M. C. C. G. [UNESP; Ruas, P. M.; Ruas, C. F.; Medri, M. E.

    2010-01-01

    The tree species Parapiptadenia rigida, native to southern South America, is frequently used in reforestation of riverbanks in Brazil. This tree is also a source of gums, tannins and essential oils, and it has some medicinal uses. We investigated flooding tolerance and genetic diversity in two populations of P. rigida; one of them was naturally exposed to flooding. Plants derived from seeds collected from each population were submitted to variable periods of experimental waterlogging and subm...

  6. Species discrimination, population structure and linkage disequilibrium in Eucalyptus camaldulensis and Eucalyptus tereticornis using SSR markers.

    Directory of Open Access Journals (Sweden)

    Shanmugapriya Arumugasundaram

    Full Text Available Eucalyptus camaldulensis and E. tereticornis are closely related species commonly cultivated for pulp wood in many tropical countries including India. Understanding the genetic structure and linkage disequilibrium (LD existing in these species is essential for the improvement of industrially important traits. Our goal was to evaluate the use of simple sequence repeat (SSR loci for species discrimination, population structure and LD analysis in these species. Investigations were carried out with the most common alleles in 93 accessions belonging to these two species using 62 SSR markers through cross amplification. The polymorphic information content (PIC ranged from 0.44 to 0.93 and 0.36 to 0.93 in E. camaldulensis and E. tereticornis respectively. A clear delineation between the two species was evident based on the analysis of population structure and species-specific alleles. Significant genotypic LD was found in E. camaldulensis, wherein out of 135 significant pairs, 17 pairs showed r(2≥0.1. Similarly, in E. tereticornis, out of 136 significant pairs, 18 pairs showed r(2≥0.1. The extent of LD decayed rapidly showing the significance of association analyses in eucalypts with higher resolution markers. The availability of whole genome sequence for E. grandis and the synteny and co-linearity in the genome of eucalypts, will allow genome-wide genotyping using microsatellites or single nucleotide polymorphims.

  7. Geographical variation in species' population responses to changes in temperature and precipitation.

    Science.gov (United States)

    Pearce-Higgins, James W; Ockendon, Nancy; Baker, David J; Carr, Jamie; White, Elizabeth C; Almond, Rosamunde E A; Amano, Tatsuya; Bertram, Esther; Bradbury, Richard B; Bradley, Cassie; Butchart, Stuart H M; Doswald, Nathalie; Foden, Wendy; Gill, David J C; Green, Rhys E; Sutherland, William J; Tanner, Edmund V J

    2015-11-07

    Despite increasing concerns about the vulnerability of species' populations to climate change, there has been little overall synthesis of how individual population responses to variation in climate differ between taxa, with trophic level or geographically. To address this, we extracted data from 132 long-term (greater than or equal to 20 years) studies of population responses to temperature and precipitation covering 236 animal and plant species across terrestrial and freshwater habitats. Our results identify likely geographical differences in the effects of climate change on populations and communities in line with macroecological theory. Temperature tended to have a greater overall impact on populations than precipitation, although the effects of increased precipitation varied strongly with latitude, being most positive at low latitudes. Population responses to increased temperature were generally positive, but did not vary significantly with latitude. Studies reporting significant climatic trends through time tended to show more negative effects of temperature and more positive effects of precipitation upon populations than other studies, indicating climate change has already impacted many populations. Most studies of climate change impacts on biodiversity have focused on temperature and are from middle to high northern latitudes. Our results suggest their findings may be less applicable to low latitudes. © 2015 The Author(s).

  8. Effective sociodemographic population assessment of elusive species in ecology and conservation management.

    Science.gov (United States)

    Head, Josephine S; Boesch, Christophe; Robbins, Martha M; Rabanal, Luisa I; Makaga, Loïc; Kühl, Hjalmar S

    2013-09-01

    Wildlife managers are urgently searching for improved sociodemographic population assessment methods to evaluate the effectiveness of implemented conservation activities. These need to be inexpensive, appropriate for a wide spectrum of species and straightforward to apply by local staff members with minimal training. Furthermore, conservation management would benefit from single approaches which cover many aspects of population assessment beyond only density estimates, to include for instance social and demographic structure, movement patterns, or species interactions. Remote camera traps have traditionally been used to measure species richness. Currently, there is a rapid move toward using remote camera trapping in density estimation, community ecology, and conservation management. Here, we demonstrate such comprehensive population assessment by linking remote video trapping, spatially explicit capture-recapture (SECR) techniques, and other methods. We apply it to three species: chimpanzees Pan troglodytes troglodytes, gorillas Gorilla gorilla gorilla, and forest elephants Loxodonta cyclotis in Loango National Park, Gabon. All three species exhibited considerable heterogeneity in capture probability at the sex or group level and density was estimated at 1.72, 1.2, and 1.37 individuals per km(2) and male to female sex ratios were 1:2.1, 1:3.2, and 1:2 for chimpanzees, gorillas, and elephants, respectively. Association patterns revealed four, eight, and 18 independent social groups of chimpanzees, gorillas, and elephants, respectively: key information for both conservation management and studies on the species' ecology. Additionally, there was evidence of resident and nonresident elephants within the study area and intersexual variation in home range size among elephants but not chimpanzees. Our study highlights the potential of combining camera trapping and SECR methods in conducting detailed population assessments that go far beyond documenting species diversity

  9. Clonality as a driver of spatial genetic structure in populations of clonal tree species.

    Science.gov (United States)

    Dering, Monika; Chybicki, Igor Jerzy; Rączka, Grzegorz

    2015-09-01

    Random genetic drift, natural selection and restricted gene dispersal are basic factors of the spatial genetic structure (SGS) in plant populations. Clonal reproduction has a profound effect on population dynamics and genetic structure and thus emerges as a potential factor in contributing to and modelling SGS. In order to assess the impact of clonality on SGS we studied clonal structure and SGS in the population of Populus alba. Six hundred and seventy-two individuals were mapped and genotyped with 16 nuclear microsatellite markers. To answer the more general question regarding the relationship between SGS and clonality we used Sp statistics, which allows for comparisons of the extent of SGS among different studies, and the comparison of published data on SGS in clonal and non-clonal tree species. Sp statistic was extracted for 14 clonal and 27 non-clonal species belonging to 7 and 18 botanical families, respectively. Results of genetic investigations conducted in the population of P. alba showed over-domination of clonal reproduction, which resulted in very low clonal diversity (R = 0.12). Significant SGS was found at both ramet (Sp = 0.095) and genet level (Sp = 0.05) and clonal reproduction was indicated as an important but not sole driving factor of SGS. Within-population structure, probably due to family structure also contributed to high SGS. High mean dominance index (D = 0.82) indicated low intermingling among genets. Literature survey revealed that clonal tree species significantly differ from non-clonal species with respect to SGS, having 2.8-fold higher SGS. This led us to conclude that clonality is a life-history trait that can have deep impact on processes acting in populations of clonal tree species leading to significant SGS.

  10. Effectiveness of Protected Areas for Representing Species and Populations of Terrestrial Mammals in Costa Rica

    Science.gov (United States)

    González-Maya, José F.; Víquez-R, Luis R.; Belant, Jerrold L.; Ceballos, Gerardo

    2015-01-01

    Costa Rica has one of the greatest percentages (26%) of protected land in the world. The National Protected Areas System (NPAS) of Costa Rica was established in 1976 and currently includes >190 protected areas within seven different protection categories. The effectiveness of the NPAS to represent species, populations, and areas with high species richness has not been properly evaluated. Such evaluations are fundamental to understand what is necessary to strengthen the NPAS and better protect biodiversity. We present a novel assessment of NPAS effectiveness in protecting mammal species. We compiled the geographical ranges of all terrestrial Costa Rican mammals then determined species lists for all protected areas and the estimated proportion of each species’ geographic range protected. We also classified mammal species according to their conservation status using the IUCN Red List of Threatened Species. We found almost complete representation of mammal species (98.5%) in protected areas, but low relative coverage (28.3% on average) of their geographic ranges in Costa Rica and 25% of the species were classified as underprotected according to a priori representation targets. Interestingly, many species-rich areas are not protected, and at least 43% of cells covering the entire country are not included in protected areas. Though protected areas in Costa Rica represent species richness well, strategic planning for future protected areas to improve species complementarity and range protection is necessary. Our results can help to define sites where new protected areas can have a greater impact on mammal conservation, both in terms of species richness and range protection. PMID:25970293

  11. Species detection and identification in sexual organisms using population genetic theory and DNA sequences.

    Directory of Open Access Journals (Sweden)

    C William Birky

    Full Text Available Phylogenetic trees of DNA sequences of a group of specimens may include clades of two kinds: those produced by stochastic processes (random genetic drift within a species, and clades that represent different species. The ratio of the mean pairwise sequence difference between a pair of clades (K to the mean pairwise sequence difference within a clade (θ can be used to determine whether the clades are samples from different species (K/θ ≥ 4 or the same species (K/θ<4 with probability ≥ 0.95. Previously I applied this criterion to delimit species of asexual organisms. Here I use data from the literature to show how it can also be applied to delimit sexual species using four groups of sexual organisms as examples: ravens, spotted leopards, sea butterflies, and liverworts. Mitochondrial or chloroplast genes are used because these segregate earlier during speciation than most nuclear genes and hence detect earlier stages of speciation. In several cases the K/θ ratio was greater than 4, confirming the original authors' intuition that the clades were sufficiently different to be assigned to different species. But the K/θ ratio split each of two liverwort species into two evolutionary species, and showed that support for the distinction between the common and Chihuahuan raven species is weak. I also discuss some possible sources of error in using the K/θ ratio; the most significant one would be cases where males migrate between different populations but females do not, making the use of maternally inherited organelle genes problematic. The K/θ ratio must be used with some caution, like all other methods for species delimitation. Nevertheless, it is a simple theory-based quantitative method for using DNA sequences to make rigorous decisions about species delimitation in sexual as well as asexual eukaryotes.

  12. Criterion 1: Conservation of biological diversity - Indicator 9: Population levels of representative species from diverse habitats monitored across their range

    Science.gov (United States)

    Carolyn Hull Sieg; Curtis H. Flather; Noah Barstatis

    2003-01-01

    This indicator estimates population trends of selected species as a surrogate measure of genetic diversity. Decreases in genetic diversity as populations decline, particularly if associated with small populations, contribute to increased risk of extinction. This indicator also provides an important measure of general biodiversity, as changes in species abundances are a...

  13. Indicator 1.08. Population levels of selected representative forest-associated species to describe genetic diversity

    Science.gov (United States)

    C. H. Sieg; S. M. Owen; C. H. Flather

    2011-01-01

    This indicator uses population trends of selected bird and tree species as a surrogate measure of genetic diversity. Population decreases, especially associated with small populations, can lead to decreases in genetic diversity, and contribute to increased risk of extinction. Many forest-associated species rely on some particular forest structure, vegetation...

  14. 77 FR 20774 - Endangered and Threatened Species; Proposed Threatened Status for Distinct Population Segments of...

    Science.gov (United States)

    2012-04-06

    ... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration 50 CFR Part 223 RIN 0648-XZ58 Endangered and Threatened Species; Proposed Threatened Status for Distinct Population Segments of the Bearded Seal AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric...

  15. EXTINCTION RISK OR LACK OF SAMPLING IN A THREATENED SPECIES: GENETIC STRUCTURE AND ENVIRONMENTAL SUITABILITY OF THE NEOTROPICAL FROG PRISTIMANTIS PENELOPUS (ANURA: CRAUGASTORIDAE)

    OpenAIRE

    RESTREPO, ADRIANA; VELASCO, JULIAN A.; DAZA, JUAN M.

    2017-01-01

    ABSTRACT IUCN Red Lists have been a valuable tool to prioritize conservation plans in endemic neotropical frogs. However, many areas in this region are poorly known in terms of their diversity and endemism. Based on examined museum specimens of the threatened species Pristimantis penelopus we revised its geographic distribution and determined the habitat suitability using niche modeling techniques. Using a mitochondrial fragment of COI gene, we determine the phylogenetic position and the exte...

  16. A Population Accounting Approach to Assess Tourism Contributions to Conservation of IUCN-Redlisted Mammal Species

    Science.gov (United States)

    Buckley, Ralf C.; Castley, J. Guy; Pegas, Fernanda de Vasconcellos; Mossaz, Alexa C.; Steven, Rochelle

    2012-01-01

    Over 1,000 mammal species are red-listed by IUCN, as Critically Endangered, Endangered or Vulnerable. Conservation of many threatened mammal species, even inside protected areas, depends on costly active day-to-day defence against poaching, bushmeat hunting, invasive species and habitat encroachment. Many parks agencies worldwide now rely heavily on tourism for routine operational funding: >50% in some cases. This puts rare mammals at a new risk, from downturns in tourism driven by external socioeconomic factors. Using the survival of individual animals as a metric or currency of successful conservation, we calculate here what proportions of remaining populations of IUCN-redlisted mammal species are currently supported by funds from tourism. This proportion is ≥5% for over half of the species where relevant data exist, ≥15% for one fifth, and up to 66% in a few cases. Many of these species, especially the most endangered, survive only in one single remaining subpopulation. These proportions are not correlated either with global population sizes or recognition as wildlife tourism icons. Most of the more heavily tourism-dependent species, however, are medium sized (>7.5 kg) or larger. Historically, biological concern over the growth of tourism in protected areas has centered on direct disturbance to wildlife. These results show that conservation of threatened mammal species has become reliant on revenue from tourism to a previously unsuspected degree. On the one hand, this provides new opportunities for conservation funding; but on the other, dependence on such an uncertain source of funding is a new, large and growing threat to red-listed species. PMID:22984467

  17. A population accounting approach to assess tourism contributions to conservation of IUCN-redlisted mammal species.

    Directory of Open Access Journals (Sweden)

    Ralf C Buckley

    Full Text Available Over 1,000 mammal species are red-listed by IUCN, as Critically Endangered, Endangered or Vulnerable. Conservation of many threatened mammal species, even inside protected areas, depends on costly active day-to-day defence against poaching, bushmeat hunting, invasive species and habitat encroachment. Many parks agencies worldwide now rely heavily on tourism for routine operational funding: >50% in some cases. This puts rare mammals at a new risk, from downturns in tourism driven by external socioeconomic factors. Using the survival of individual animals as a metric or currency of successful conservation, we calculate here what proportions of remaining populations of IUCN-redlisted mammal species are currently supported by funds from tourism. This proportion is ≥ 5% for over half of the species where relevant data exist, ≥ 15% for one fifth, and up to 66% in a few cases. Many of these species, especially the most endangered, survive only in one single remaining subpopulation. These proportions are not correlated either with global population sizes or recognition as wildlife tourism icons. Most of the more heavily tourism-dependent species, however, are medium sized (>7.5 kg or larger. Historically, biological concern over the growth of tourism in protected areas has centered on direct disturbance to wildlife. These results show that conservation of threatened mammal species has become reliant on revenue from tourism to a previously unsuspected degree. On the one hand, this provides new opportunities for conservation funding; but on the other, dependence on such an uncertain source of funding is a new, large and growing threat to red-listed species.

  18. Data on Population Dynamics of Three Syntopic Newt Species from Western Romania

    Directory of Open Access Journals (Sweden)

    Alfred-S. Cicort-Lucaciu

    2011-12-01

    Full Text Available We studied the population dynamics of three syntopic newt species [Mesotriton alpestris (Laurenti, 1768, Lissotriton vulgaris (Linnaeus, 1758 and Triturus cristatus (Laurenti, 1768] in Zarand Mountains (Arad County, Romania. M. alpestris had the shortest aquatic phase, approximately two months, out of which the nuptial display was 2-3 weeks long. L. vulgaris and T. cristatus spent three months in the habitat, having a nuptial display of 2-3 weeks for L. vulgaris, and of 4-5 weeks for T. cristatus. M. alpestris had the highest degree of reproductive synchronization, while this was the lowest at T. cristatus. Males from all three species had a higher affinity for the aquatic habitat than females. The population size was estimated at 769 for L. vulgaris, 588 for T. cristatus, and 294 for M. alpestris. Balanced sex ratio was observed in the peak of breeding activity for all species.

  19. Estimation of avian population sizes and species richness across a boreal landscape in Alaska

    Science.gov (United States)

    Handel, C.M.; Swanson, S.A.; Nigro, Debora A.; Matsuoka, S.M.

    2009-01-01

    We studied the distribution of birds breeding within five ecological landforms in Yukon-Charley Rivers National Preserve, a 10,194-km2 roadless conservation unit on the Alaska-Canada border in the boreal forest zone. Passerines dominated the avifauna numerically, comprising 97% of individuals surveyed but less than half of the 115 species recorded in the Preserve. We used distance-sampling and discrete-removal models to estimate detection probabilities, densities, and population sizes across the Preserve for 23 species of migrant passerines and five species of resident passerines. Yellow-rumped Warblers (Dendroica coronata) and Dark-eyed Juncos (Junco hyemalis) were the most abundant species, together accounting for 41% of the migrant passerine populations estimated. White-winged Crossbills (Loxia leucoptera), Boreal Chickadees (Poecile hudsonica), and Gray Jays (Perisoreus canadensis) were the most abundant residents. Species richness was greatest in the Floodplain/Terrace landform flanking the Yukon River but densities were highest in the Subalpine landform. Species composition was related to past glacial history and current physiography of the region and differed notably from other areas of the northwestern boreal forest. Point-transect surveys, augmented with auxiliary observations, were well suited to sampling the largely passerine avifauna across this rugged landscape and could be used across the boreal forest region to monitor changes in northern bird distribution and abundance. ?? 2009 The Wilson Ornithological Society.

  20. Genetic Differentiations among the Populations of Salvia japonica (Lamiaceae and Its Related Species

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    SUDARMONO

    2008-03-01

    Full Text Available Morphological and genetic variations within Salvia japonica (Lamiaceae and its related species in Japan were analyzed for clarifying their taxonomic significance. The genetic variations were explored through chloroplast and nuclear ribosomal DNA sequences and allozyme polymorphisms. Since chromosome numbers characterized the genus of Salvia, we also examined whether the karyotypes were different. We examined 58 populations of S. japonica and 14 populations of others species of Salvia. Among the populations of S. japonica represented four forms (f. japonica, f. longipes, f. lanuginosa and f. albiflora. The size of chromosomes were various among Salvia spp. Based on the allozyme as well as the DNA sequence, the populations of S. japonica separated from the others Salvia species. The populations of S. japonica exhibited four combinations of the morphological characters. However, these combinations did not correlate to the four forms of S. japonica. In addition, the morphological variations did not correlate to the allozyme and DNA sequences. It is suggested that the four morphological variations as well as the four form of S. japonica should not considered to be a taxonomic unit; accordingly, S. japonica were considered to be still at the early stage of speciation process.

  1. Families of transposable elements, population structure and the origin of species.

    Science.gov (United States)

    Jurka, Jerzy; Bao, Weidong; Kojima, Kenji K

    2011-09-19

    Eukaryotic genomes harbor diverse families of repetitive DNA derived from transposable elements (TEs) that are able to replicate and insert into genomic DNA. The biological role of TEs remains unclear, although they have profound mutagenic impact on eukaryotic genomes and the origin of repetitive families often correlates with speciation events. We present a new hypothesis to explain the observed correlations based on classical concepts of population genetics. The main thesis presented in this paper is that the TE-derived repetitive families originate primarily by genetic drift in small populations derived mostly by subdivisions of large populations into subpopulations. We outline the potential impact of the emerging repetitive families on genetic diversification of different subpopulations, and discuss implications of such diversification for the origin of new species. Several testable predictions of the hypothesis are examined. First, we focus on the prediction that the number of diverse families of TEs fixed in a representative genome of a particular species positively correlates with the cumulative number of subpopulations (demes) in the historical metapopulation from which the species has emerged. Furthermore, we present evidence indicating that human AluYa5 and AluYb8 families might have originated in separate proto-human subpopulations. We also revisit prior evidence linking the origin of repetitive families to mammalian phylogeny and present additional evidence linking repetitive families to speciation based on mammalian taxonomy. Finally, we discuss evidence that mammalian orders represented by the largest numbers of species may be subject to relatively recent population subdivisions and speciation events. The hypothesis implies that subdivision of a population into small subpopulations is the major step in the origin of new families of TEs as well as of new species. The origin of new subpopulations is likely to be driven by the availability of new

  2. Extinction risk assessment for the species survival plan (SSP) population of the Bali mynah (Leucopsar rothschildi).

    Science.gov (United States)

    Earnhardt, Joanne M; Thompson, Steven D; Faust, Lisa J

    2009-05-01

    The Bali mynah Species Survival Plan (SSP), an Association of Zoos and Aquariums program, strives to maintain the genetic and demographic health of its population, avoid unplanned changes in size, and minimize the risk of population extinction. The SSP population meets current demographic and genetic objectives with a population size of 209 birds at 61 institutions and 96% genetic diversity (GD) retained from the source population. However, participating institutions have expressed concerns regarding space allocation, target population size (TPS), breeding restrictions, inbreeding depression, and harvest in relation to future population availability and viability. Based on these factors, we assess five questions with a quantitative risk assessment, specifically a population viability analysis (PVA) using ZooRisk software. Using an individual-based stochastic model, we project potential population changes under different conditions (e.g. changes in TPS and genetic management) to identify the most effective management actions. Our projections indicate that under current management conditions, population decline and extinction are unlikely and that although GD will decline over 100 years the projected loss does not exceed levels acceptable to population managers (less than 90% GD retained). Model simulations indicate that the combination of two genetic management strategies (i.e. priority breeding based on mean kinship and inbreeding avoidance) benefits the retention of GD and reduces the accumulation of inbreeding. The current TPS (250) is greater than necessary to minimize the risk of extinction for the SSP population but any reduction in TPS must be accompanied by continued application of genetic management. If carefully planned, birds can be harvested for transfer to Bali for a reintroduction program without jeopardizing the SSP population.

  3. Climate, invasive species and land use drive population dynamics of a cold-water specialist

    Science.gov (United States)

    Kovach, Ryan P.; Al-Chokhachy, Robert K.; Whited, Diane C.; Schmetterling, David A.; Dux, Andrew M; Muhlfeld, Clint C.

    2017-01-01

    Climate change is an additional stressor in a complex suite of threats facing freshwater biodiversity, particularly for cold-water fishes. Research addressing the consequences of climate change on cold-water fish has generally focused on temperature limits defining spatial distributions, largely ignoring how climatic variation influences population dynamics in the context of other existing stressors.We used long-term data from 92 populations of bull trout Salvelinus confluentus – one of North America's most cold-adapted fishes – to quantify additive and interactive effects of climate, invasive species and land use on population dynamics (abundance, variability and growth rate).Populations were generally depressed, more variable and declining where spawning and rearing stream habitat was limited, invasive species and land use were prevalent and stream temperatures were highest. Increasing stream temperature acted additively and independently, whereas land use and invasive species had additive and interactive effects (i.e. the impact of one stressor depended on exposure to the other stressor).Most (58%–78%) of the explained variation in population dynamics was attributed to the presence of invasive species, differences in life history and management actions in foraging habitats in rivers, lakes and reservoirs. Although invasive fishes had strong negative effects on populations in foraging habitats, proactive control programmes appeared to effectively temper their negative impact.Synthesis and applications. Long-term demographic data emphasize that climate warming will exacerbate imperilment of cold-water specialists like bull trout, yet other stressors – especially invasive fishes – are immediate threats that can be addressed by proactive management actions. Therefore, climate-adaptation strategies for freshwater biodiversity should consider existing abiotic and biotic stressors, some of which provide potential and realized opportunity for conservation

  4. Using temporal sampling to improve attribution of source populations for invasive species.

    Directory of Open Access Journals (Sweden)

    Sharyn J Goldstien

    Full Text Available Numerous studies have applied genetic tools to the identification of source populations and transport pathways for invasive species. However, there are many gaps in the knowledge obtained from such studies because comprehensive and meaningful spatial sampling to meet these goals is difficult to achieve. Sampling populations as they arrive at the border should fill the gaps in source population identification, but such an advance has not yet been achieved with genetic data. Here we use previously acquired genetic data to assign new incursions as they invade populations within New Zealand ports and marinas. We also investigated allelelic frequency change in these recently established populations over a two-year period, and assessed the effect of temporal genetic sampling on our ability to assign new incursions to their population of source. We observed shifts in the allele frequencies among populations, as well as the complete loss of some alleles and the addition of alleles novel to New Zealand, within these recently established populations. There was no significant level of genetic differentiation observed in our samples between years, and the use of these temporal data did alter the assignment probability of new incursions. Our study further suggests that new incursions can add genetic variation to the population in a single introduction event as the founders themselves are often more genetically diverse than theory initially predicted.

  5. Population and hierarchy of active species in gold iron oxide catalysts for carbon monoxide oxidation

    Science.gov (United States)

    He, Qian; Freakley, Simon J.; Edwards, Jennifer K.; Carley, Albert F.; Borisevich, Albina Y.; Mineo, Yuki; Haruta, Masatake; Hutchings, Graham J.; Kiely, Christopher J.

    2016-01-01

    The identity of active species in supported gold catalysts for low temperature carbon monoxide oxidation remains an unsettled debate. With large amounts of experimental evidence supporting theories of either gold nanoparticles or sub-nm gold species being active, it was recently proposed that a size-dependent activity hierarchy should exist. Here we study the diverging catalytic behaviours after heat treatment of Au/FeOx materials prepared via co-precipitation and deposition precipitation methods. After ruling out any support effects, the gold particle size distributions in different catalysts are quantitatively studied using aberration corrected scanning transmission electron microscopy (STEM). A counting protocol is developed to reveal the true particle size distribution from HAADF-STEM images, which reliably includes all the gold species present. Correlation of the populations of the various gold species present with catalysis results demonstrate that a size-dependent activity hierarchy must exist in the Au/FeOx catalyst. PMID:27671143

  6. Life histories predict genetic diversity and population structure within three species of octopus targeted by small-scale fisheries in Northwest Mexico

    Science.gov (United States)

    Ceballos-Vázquez, Bertha P.; Arellano-Martínez, Marcial; García-Rodríguez, Francisco J.; Culver, Melanie; Reyes-Bonilla, Hector

    2018-01-01

    The fishery for octopus in Northwest Mexico has increased to over 2,000 tons annually, but to date the specific composition of the catch has been ignored. With at least three main species targeted by artisanal fisheries in the region with distinct life histories, the lack of basic biological information about the distribution, metapopulation size and structure of each species could impede effective fisheries management to avoid overexploitation. We tested if different life histories of three species of octopus could help predict observed patterns of genetic diversity, population dynamics, structure and connectivity and how this information could be relevant to the sustainable management of the fishery. We sequenced two mitochondrial genes and genotyped seven nuclear microsatellite loci to identify the distribution of each species in 20 locations from the Gulf of California and the west coast of the Baja California peninsula. We tested five hypotheses derived from population genetic theory based on differences in the fecundity and dispersal potential for each species. We discovered that Octopus bimaculoides with low fecundity and direct development (without a planktonic phase) had lower average effective population size and genetic diversity, but higher levels of kinship, population structure, and richness of private alleles, than the other two species. These features indicated limited dispersal and high local recruitment. In contrast, O. bimaculatus and O. hubbsorum with higher fecundity and planktonic phase as paralarvae had higher effective population size and genetic diversity, and overall lower kinship and population structure than O. bimaculoides. These observations supported higher levels of gene flow over a larger geographical scale. O. bimaculatus with the longest planktonic paralarval duration and therefore larger dispersal potential had differences in the calculated parameters possibly associated with increased connectivity. We propose O

  7. Does sex-biased dispersal account for the lack of geographic and host-associated differentiation in introduced populations of an aphid parasitoid?

    Science.gov (United States)

    Zepeda-Paulo, Francisca; Lavandero, Blas; Mahéo, Frédérique; Dion, Emilie; Outreman, Yannick; Simon, Jean-Christophe; Figueroa, Christian C

    2015-06-01

    Host recognition and use in female parasitoids strongly relies on host fidelity, a plastic behavior which can significantly restrict the host preferences of parasitoids, thus reducing the gene flow between parasitoid populations attacking different insect hosts. However, the effect of migrant males on the genetic differentiation of populations has been frequently ignored in parasitoids, despite its known impact on gene flow between populations. Hence, we studied the extent of gene flow mediated by female and male parasitoids by assessing sibship relationships among parasitoids within and between populations, and its impact on geographic and host-associated differentiation in the aphid parasitoid Aphidius ervi. We report evidences of a high gene flow among parasitoid populations on different aphid hosts and geographic locations. The high gene flow among parasitoid populations was found to be largely male mediated, suggested by significant differences in the distribution of full-sib and paternal half-sib dyads of parasitoid populations.

  8. Population genetic structure of Monimopetalum chinense (Celastraceae), an endangered endemic species of eastern China.

    Science.gov (United States)

    Xie, Guo-Wen; Wang, De-Lian; Yuan, Yong-Ming; Ge, Xue-Jun

    2005-04-01

    Monimopetalum chinense (Celastraceae) standing for the monotypic genus is endemic to eastern China. Its conservation status is vulnerable as most populations are small and isolated. Monimopetalum chinense is capable of reproducing both sexually and asexually. The aim of this study was to understand the genetic structure of M. chinense and to suggest conservation strategies. One hundred and ninety individuals from ten populations sampled from the entire distribution area of M. chinense were investigated by using inter-simple sequence repeats (ISSR). A total of 110 different ISSR bands were generated using ten primers. Low levels of genetic variation were revealed both at the species level (Isp=0.183) and at the population level (Ipop=0.083). High clonal diversity (D = 0.997) was found, and strong genetic differentiation among populations was detected (49.06 %). Small population size, possible inbreeding, limited gene flow due to short distances of seed dispersal, fragmentation of the once continuous range and subsequent genetic drift, may have contributed to shaping the population genetic structure of the species.

  9. Population Size and Decadal Trends of Three Penguin Species Nesting at Signy Island, South Orkney Islands.

    Science.gov (United States)

    Dunn, Michael J; Jackson, Jennifer A; Adlard, Stacey; Lynnes, Amanda S; Briggs, Dirk R; Fox, Derren; Waluda, Claire M

    2016-01-01

    We report long-term changes in population size of three species of sympatrically breeding pygoscelid penguins: Adélie (Pygoscelis adeliae), chinstrap (Pygoscelis antarctica) and gentoo (Pygoscelis papua ellsworthii) over a 38 year period at Signy Island, South Orkney Islands, based on annual counts from selected colonies and decadal all-island systematic counts of occupied nests. Comparing total numbers of breeding pairs over the whole island from 1978/79 to 2015/16 revealed varying fortunes: gentoo penguin pairs increased by 255%, (3.5% per annum), chinstrap penguins declined by 68% (-3.6% per annum) and Adélie penguins declined by 42% (-1.5% per annum). The chinstrap population has declined steadily over the last four decades. In contrast, Adélie and gentoo penguins have experienced phases of population increase and decline. Annual surveys of selected chinstrap and Adélie colonies produced similar trends from those revealed by island-wide surveys, allowing total island population trends to be inferred relatively well. However, while the annual colony counts of chinstrap and Adélie penguins showed a trend consistent in direction with the results from all-island surveys, the magnitude of estimated population change was markedly different between colony wide and all island counts. Annual population patterns suggest that pair numbers in the study areas partly reflect immigration and emigration of nesting birds between different parts of the island. Breeding success for all three species remained broadly stable over time in the annually monitored colonies. Breeding success rates in gentoo and chinstrap penguins were strongly correlated, despite the differing trends in population size. This study shows the importance of effective, standardised monitoring to accurately determine long-term population trajectories. Our results indicate significant declines in the Adélie and chinstrap penguin populations at Signy Island over the last five decades, and a gradual

  10. Population Size and Decadal Trends of Three Penguin Species Nesting at Signy Island, South Orkney Islands.

    Directory of Open Access Journals (Sweden)

    Michael J Dunn

    Full Text Available We report long-term changes in population size of three species of sympatrically breeding pygoscelid penguins: Adélie (Pygoscelis adeliae, chinstrap (Pygoscelis antarctica and gentoo (Pygoscelis papua ellsworthii over a 38 year period at Signy Island, South Orkney Islands, based on annual counts from selected colonies and decadal all-island systematic counts of occupied nests. Comparing total numbers of breeding pairs over the whole island from 1978/79 to 2015/16 revealed varying fortunes: gentoo penguin pairs increased by 255%, (3.5% per annum, chinstrap penguins declined by 68% (-3.6% per annum and Adélie penguins declined by 42% (-1.5% per annum. The chinstrap population has declined steadily over the last four decades. In contrast, Adélie and gentoo penguins have experienced phases of population increase and decline. Annual surveys of selected chinstrap and Adélie colonies produced similar trends from those revealed by island-wide surveys, allowing total island population trends to be inferred relatively well. However, while the annual colony counts of chinstrap and Adélie penguins showed a trend consistent in direction with the results from all-island surveys, the magnitude of estimated population change was markedly different between colony wide and all island counts. Annual population patterns suggest that pair numbers in the study areas partly reflect immigration and emigration of nesting birds between different parts of the island. Breeding success for all three species remained broadly stable over time in the annually monitored colonies. Breeding success rates in gentoo and chinstrap penguins were strongly correlated, despite the differing trends in population size. This study shows the importance of effective, standardised monitoring to accurately determine long-term population trajectories. Our results indicate significant declines in the Adélie and chinstrap penguin populations at Signy Island over the last five decades, and a

  11. Habitat shift in invading species: Zebra and quagga mussel population characteristics on shallow soft substrates

    Science.gov (United States)

    Berkman, P.A.; Garton, D.W.; Haltuch, M.A.; Kennedy, G.W.; Febo, L.R.

    2000-01-01

    Unexpected habitat innovations among invading species are illustrated by the expansion of dreissenid mussels across sedimentary environments in shallow water unlike the hard substrates where they are conventionally known. In this note, records of population characteristics of invading zebra (Dreissena polymorpha) and quagga (Dreissena bugensis) mussels from 1994 through 1998 are reported from shallow (less than 20 m) sedimentary habitats in western Lake Erie. Haphazard SCUBA collections of these invading species indicated that combined densities of zebra and quagga mussels ranged from 0 to 32,500 individuals per square meter between 1994 and 1998, with D. polymorpha comprising 75-100% of the assemblages. These mixed mussel populations, which were attached by byssal threads to each other and underlying sand-grain sediments, had size-frequency distributions that were typical of colonizing populations on hard substrates. Moreover, the presence of two mussel cohorts within the 1994 samples indicated that these species began expanding onto soft substrates not later than 1992, within 4 years of their initial invasion in western Lake Erie. Such historical data provide baselines for interpreting adaptive innovations, ecological interactions and habitat shifts among the two invading dreissenid mussel species in North America.

  12. Population assessment and degree of threat of chalybea Macrocarpa (Melastomataceae) endemic species from Colombia

    International Nuclear Information System (INIS)

    Gil Leguizamon, Pablo Andres; Morales Puentes, Maria Eugenia; Diaz Perez, Carlos Nelson

    2014-01-01

    Population assessment results from chalybea macrocarpaare shown, the specie is considerate ENDANGERED (EN) by its restricted area, threatened is generated by crops and extensive cattle farming. the study was conducted in the Boyaca Department (Colombia), Municipality of Arcabuco, in three established localities using herbarium and literature information; field work made possible identified distribution, density and phenology like sub criteria, allowing identify the presence extension and occupancy area. We took structural data (height, coverage and DBH) to determinate the population age's classes. Which the gathered information and the associated vegetation, the specie is re-categorized which the b IUCN criteria. It is distributed to the northwest and southern in Arcabuco, in an area of 59.9 km 2 , 4 km 2 of occupancy and a population density of 50 individual/km 2 . Flowering and fruiting is continuous through the year, however, most of the flowering is from March to August and fruiting from September to February. Age structure allows identified ten species between seedlings, juveniles and adults. Population is represented by few seedling individuals (10.6 %) and juveniles (20.9 %) versus adults (68.5 %). finally, C. macrocarpais upgraded to Critical Risk (CR B1ab (iii)).

  13. Assessing spatial and temporal population dynamics of cryptic species: an example with the European pond turtle.

    Science.gov (United States)

    Olivier, Anthony; Barbraud, Christophe; Rosecchi, Elisabeth; Germain, Christophe; Cheylan, Marc

    2010-06-01

    Within the current context of biodiversity loss a number of biodiversity indicators have been developed to help measure the state of nature and how it is changing. However, most indicators are derived from bird populations. Reptiles and amphibians could be useful ecosystem indicators, but this requires obtaining precise and unbiased population parameters. This is a particularly challenging task for these two groups of species, because individuals are extremely difficult to detect for various reasons. We illustrate the use of a sampling and analytical method that explicitly takes into account imperfect detection to assess the population dynamics of a reptile species and its temporal and spatial variation. European pond turtles (Emys orbicularis) were sampled at two different locations during a 10-year study. The two sites differed by their water management regimes and number of livestock. At each site and for each sex, the data were modeled using a robust design capture-mark-recapture framework to obtain and compare estimates of survival, temporary emigration, time-specific abundance, density, and population growth rate, while taking into account effects of individual heterogeneity, trap-response, and time on capture probabilities. Temporary emigration was higher in males (0.344 +/- 0.046) (mean +/- SE) than in females (0.228 +/- 0.071), did not differ between sites for each sex, and was mainly Markovian. Apparent adult survival was higher in females (0.966 +/- 0.031) than in males (0.864 +/- 0.024), and was negatively related to the proportion of individuals with repaired shell fractures in the population. Average density was 63.7 +/- 6.6 turtles/km2 but was higher for females (39.2 +/- 14.0 females/km2) than for males (23.5 +/- 5.7 males/km2). The population sizes of males and females decreased where long periods of artificial drought and the highest density of livestock occurred. This research highlights differences in demographic parameters according to sex and

  14. Population Development of Several Species of Ants on the Cocoa Trees in South Sulawesi

    Directory of Open Access Journals (Sweden)

    Fatahuddin Fatahuddin

    2010-08-01

    Full Text Available Several species of ants with different behavior have been found in cocoa plantations and their behavior is important to be considered because it might be correlated with the degree of protection of cocoa plant from cocoa pests. The aim of this research is to manipulate and to develop ants population in environment, so they are able to establish permanently in cocoa trees. This research was conducted in Papakaju Regions Luwu Regency in Juli to November 2009. In this study, 10 cocoa trees with ants were sampled (each species of ant in 10 cocoa trees. A control of 10 tree samples without ant was also taken. In order to assess the abundance of ant population, it was grouped based on scoring, which score 1 for less than 20 ants, score 2 for 21–50 ants, score 3 for 51–200 ants, score 4 for 201–1000 ants, and score 5 for more than 1000 per tree. The results indicated that average of population score of the three ants species reached the highest population for the Oecophylla. smaragdina with average score 4.85 (>1000 ants, Dolichoderus thoracicus, with average score 3.90 (> 200 ants and Crematogaster. difformis with average score 3.10 (>200 ants. This research indicated that three species of ants, Oecophylla smaragdina (weaver ant, Dolichoderus thoracicus (cocoa black ant and Crematogaster difformis (cracking ant. in farmer cocoa plantations in South Sulawesi giving better performance against major pests of cocoa in particular cocoa pod borer (CPB. Key words: Ant Population, Oecophylla smaragdina, Dolichoderus thoracicus, Crematogaster difformis, artificial nest, cocoa.

  15. Lack of resources a major obstacle in program implementation. Niigata declaration. Parliamentarians pledge to translate commitment into support for population policies.

    Science.gov (United States)

    1999-01-01

    This article presents the reaffirmation of the 96 parliamentarians from 28 countries during the international conference in Niigata, Japan, concerning their pledge in translating their commitment into supporting the population policies and development. The Programme of Action of the International Conference on Population and Development (ICPD) and the Cairo Declaration on Population and Development were embraced by the parliamentarians. The ICPD+5 process and the International Forum of Parliamentarians on ICPD Review were utilized in the guideline implementation of the ICPD Programme of Action. The governments were solicited to implement and monitor the progress of the ICPD Programme of Action in addressing the need for water, food, natural resources, environment and population, reproductive health and gender equality. Recognizing the inseparable relationship between population and sustainable development, governments were urge to ensure that international understanding and conventions must be consistent with the provision of food security and human survival. The organization implores the UN and the UN Population Fund to pursue its role in the formulation and implementation of population policies in different countries and regional organizations like the Association of South-East Asian Nations and the South Asian Association for Regional Cooperation. The goal of the Asian Forum of Parliamentarians on Population and Development is to address the population and developmental problems in a comprehensive and integral fashion and the development of a worldwide network of concerned parliamentarians for the promotion of peace, prosperity and equality.

  16. Effects of glyphosate formulations on the population dynamics of two freshwater cladoceran species.

    Science.gov (United States)

    Reno, U; Doyle, S R; Momo, F R; Regaldo, L; Gagneten, A M

    2018-02-05

    The general objective of this work is to experimentally assess the effects of acute glyphosate pollution on two freshwater cladoceran species (Daphnia magna and Ceriodaphnia dubia) and to use this information to predict the population dynamics and the potential for recovery of exposed organisms. Five to six concentrations of four formulations of glyphosate (4-Gly) (Eskoba ® , Panzer Gold ® , Roundup Ultramax ® and Sulfosato Touchdown ® ) were evaluated in both cladoceran species through acute tests and 15-day recovery tests in order to estimate the population dynamics of microcrustaceans. The endpoints of the recovery test were: survival, growth (number of molts), fecundity, and the intrinsic population growth rate (r). A matrix population model (MPM) was applied to r of the survivor individuals of the acute tests, followed by a Monte Carlo simulation study. Among the 4-Gly tested, Sulfosato Touchdown ® was the one that showed higher toxicity, and C. dubia was the most sensitive species. The Monte Carlo simulation study showed an average value of λ always <1 for D. magna, indicating that its populations would not be able to survive under natural environmental conditions after an acute Gly exposure between 0.25 and 35 a.e. mg L -1 . The average value of λ for C. dubia was also <1 after exposure to Roundup Ultramax ® : 1.30 and 1.20 for 1.21 and 2.5 mg a.e. L -1 ,respectively. The combined methodology-recovery tests and the later analysis through MPM with a Monte Carlo simulation study-is proposed to integrate key demographic parameters and predict the possible fate of microcrustacean populations after being exposed to acute 4-Gly contamination events.

  17. Repeatability and reproducibility of Population Viability Analysis (PVA and the implications for threatened species management

    Directory of Open Access Journals (Sweden)

    Clare Morrison

    2016-08-01

    Full Text Available Conservation triage focuses on prioritizing species, populations or habitats based on urgency, biodiversity benefits, recovery potential as well as cost. Population Viability Analysis (PVA is frequently used in population focused conservation prioritizations. The critical nature of many of these management decisions requires that PVA models are repeatable and reproducible to reliably rank species and/or populations quantitatively. This paper assessed the repeatability and reproducibility of a subset of previously published PVA models. We attempted to rerun baseline models from 90 publicly available PVA studies published between 2000-2012 using the two most common PVA modelling software programs, VORTEX and RAMAS-GIS. Forty percent (n = 36 failed, 50% (45 were both repeatable and reproducible, and 10% (9 had missing baseline models. Repeatability was not linked to taxa, IUCN category, PVA program version used, year published or the quality of publication outlet, suggesting that the problem is systemic within the discipline. Complete and systematic presentation of PVA parameters and results are needed to ensure that the scientific input into conservation planning is both robust and reliable, thereby increasing the chances of making decisions that are both beneficial and defensible. The implications for conservation triage may be far reaching if population viability models cannot be reproduced with confidence, thus undermining their intended value.

  18. Population genetics of four heavily exploited shark species around the Arabian Peninsula

    KAUST Repository

    Spaet, Julia L.Y.

    2015-05-01

    The northwestern Indian Ocean harbors a number of larger marine vertebrate taxa that warrant the investigation of genetic population structure given remarkable spatial heterogeneity in biological characteristics such as distribution, behavior, and morphology. Here, we investigate the genetic population structure of four commercially exploited shark species with different biological characteristics (Carcharhinus limbatus, Carcharhinus sorrah, Rhizoprionodon acutus, and Sphyrna lewini) between the Red Sea and all other water bodies surrounding the Arabian Peninsula. To assess intraspecific patterns of connectivity, we constructed statistical parsimony networks among haplotypes and estimated (1) population structure; and (2) time of most recent population expansion, based on mitochondrial control region DNA and a total of 20 microsatellites. Our analysis indicates that, even in smaller, less vagile shark species, there are no contemporary barriers to gene flow across the study region, while historical events, for example, Pleistocene glacial cycles, may have affected connectivity in C. sorrah and R. acutus. A parsimony network analysis provided evidence that Arabian S. lewini may represent a population segment that is distinct from other known stocks in the Indian Ocean, raising a new layer of conservation concern. Our results call for urgent regional cooperation to ensure the sustainable exploitation of sharks in the Arabian region.

  19. Differentiation of cGMP-dependent and -independent nitric oxide effects on platelet apoptosis and reactive oxygen species production using platelets lacking soluble guanylyl cyclase.

    Science.gov (United States)

    Rukoyatkina, N; Walter, U; Friebe, A; Gambaryan, S

    2011-11-01

    Platelet activation is an irreversible process resulting in platelet apoptosis and necrosis, and circulating platelets contain many components of the apoptotic machinery. Cyclic guanosine monophosphate (cGMP) generated by nitric oxide (NO) activated soluble guanylyl cyclase (sGC) plays a crucial role in preventing platelet activation. However, in addition to activation of sGC, cGMP-independent NO effects in platelets have been described. To differentiate between cGMP-dependent and -independent NO effects on platelet apoptosis and reactive oxygen species (ROS) production, we generated platelet-specific sGC-deficient mice (PS-GCKO). Platelet apoptosis was induced by a combination of thrombin/convulxin (Thr/Cvx) and assessed by phosphatidylserine (PS) surface exposure, and loss of the mitochondrial membrane potential. NO-induced inhibition of PS externalisation was mediated only by cGMP-dependent mechanisms. Inhibition of the mitochondrial membrane potential decrease at low NO concentration was also cGMP-dependent but became cGMP-independent at high NO concentrations. In contrast, inhibition of ROS formation at any NO concentration was mediated by cGMP-independent mechanisms, very likely due to direct radical scavenging. NO inhibits platelet apoptosis by cGMP-dependent mechanisms and ROS production by cGMP-independent mechanisms. The PS-GCKO mouse model is an important tool for the differentiation of cGMP-dependent and -independent NO effects on platelets.

  20. Emergence of target waves in paced populations of cyclically competing species

    International Nuclear Information System (INIS)

    Jiang Luoluo; Zhou Tao; Wang Binghong; Perc, Matjaz; Huang Xin

    2009-01-01

    We investigate the emergence of target waves in a cyclic predator-prey model incorporating a periodic current of the three competing species in a small area situated at the center of a square lattice. The periodic current acts as a pacemaker, trying to impose its rhythm on the overall spatiotemporal evolution of the three species. We show that the pacemaker is able to nucleate target waves that eventually spread across the whole population, whereby three routes leading to this phenomenon can be distinguished depending on the mobility of the three species and the oscillation period of the localized current. First, target waves can emerge due to the synchronization between the periodic current and oscillations of the density of the three species on the spatial grid. The second route is similar to the first, the difference being that the synchronization sets in only intermittently. Finally, the third route toward target waves is realized when the frequency of the pacemaker is much higher than that characterizing the oscillations of the overall density of the three species. By considering the mobility and frequency of the current as variable parameters, we thus provide insights into the mechanisms of pattern formation resulting from the interplay between local and global dynamics in systems governed by cyclically competing species.

  1. Chromosome polymorphism and complements in populations of Girardia species (Platyhelminthes, Tricladida, Paludicola from southern Brazil

    Directory of Open Access Journals (Sweden)

    E. Benya

    Full Text Available The karyotypes of four species of freshwater triclads of the genus Girardia (Platyhelminthes, i.e. G. schubarti, G. tigrina, G. anderlani, and G. biapertura, from populations of different localities of the Rio Grande do Sul State, in southern Brazil, were analyzed. The karyotype of G. biapertura is presented for the first time. Three basic complements of 4, 8, and 9 chromosomes were found. Diploids, triploids, or mixoploids (2n/3n specimens were frequently detected in these populations. The basic chromosomal complement of n = 9 was verified in two different species (G. biapertura and G. anderlani, presenting a large acrocentric chromosome which is rare in the family Dugesiidae. An intra and interspecific chromosomal variability was also detected and its evolutionary implications are discussed.

  2. Global Existence Analysis of Cross-Diffusion Population Systems for Multiple Species

    Science.gov (United States)

    Chen, Xiuqing; Daus, Esther S.; Jüngel, Ansgar

    2018-02-01

    The existence of global-in-time weak solutions to reaction-cross-diffusion systems for an arbitrary number of competing population species is proved. The equations can be derived from an on-lattice random-walk model with general transition rates. In the case of linear transition rates, it extends the two-species population model of Shigesada, Kawasaki, and Teramoto. The equations are considered in a bounded domain with homogeneous Neumann boundary conditions. The existence proof is based on a refined entropy method and a new approximation scheme. Global existence follows under a detailed balance or weak cross-diffusion condition. The detailed balance condition is related to the symmetry of the mobility matrix, which mirrors Onsager's principle in thermodynamics. Under detailed balance (and without reaction) the entropy is nonincreasing in time, but counter-examples show that the entropy may increase initially if detailed balance does not hold.

  3. The roles of competition and habitat in the dynamics of populations and species distributions

    Science.gov (United States)

    Yackulic, Charles Brandon; Reid, Janice; Nichols, James D.; Hines, James E.; Davis, Raymond; Forsman, Eric

    2014-01-01

    The role of competition in structuring biotic communities at fine spatial scales is well known from detailed process-based studies. Our understanding of competition's importance at broader scales is less resolved and mainly based on static species distribution maps. Here, we bridge this gap by examining the joint occupancy dynamics of an invading (barred owl: Strix varia) and a resident species (Northern spotted owl: Strix occidentalis caurina) in a 1000 km2 study area over a 22 - year period. Past studies of these competitors have focused on the dynamics of one species at a time, hindering efforts to parse out the roles of habitat and competition and to forecast the future of the resident species. In addition, while these studies accounted for the imperfect detection of the focal species, no multiseason analysis of these species has accounted for the imperfect detection of the secondary species, potentially biasing inference. We analyze survey data using models that combine the general multistate-multiseason occupancy modeling framework with autologistic modeling - allowing us to account for important aspects of our study system. We find that local extinction probability increases for each species when the other is present; however, the effect of the invader on the resident is greater. Although the species prefer different habitats, these habitats are highly correlated at the patch scale and the impacts of invader on the resident are greatest in patches that would otherwise be optimal. As a consequence, competition leads to a weaker relationship between habitat and Northern spotted owl occupancy. Colonization and extinction rates of the invader are closely related to neighborhood occupancy, and over the first half of the study the availability of colonists limited the rate of population growth. Competition is likely to exclude the resident species both through its immediate effects on local extinction, and by indirectly lowering colonization rates as Northern

  4. Integration of genetic and demographic data to assess population risk in a continuously distributed species

    Science.gov (United States)

    Fedy, Bradley C.; Row, Jeffery R.; Oyler-McCance, Sara J.

    2017-01-01

    The identification and demographic assessment of biologically meaningful populations is fundamental to species’ ecology and management. Although genetic tools are used frequently to identify populations, studies often do not incorporate demographic data to understand their respective population trends. We used genetic data to define subpopulations in a continuously distributed species. We assessed demographic independence and variation in population trends across the distribution. Additionally, we identified potential barriers to gene flow among subpopulations. We sampled greater sage-grouse (Centrocercus urophasianus) leks from across their range (≈175,000 Km2) in Wyoming and amplified DNA at 14 microsatellite loci for 1761 samples. Subsequently, we assessed population structure in unrelated individuals (n = 872) by integrating results from multiple Bayesian clustering approaches and used the boundaries to inform our assessment of long-term population trends and lek activity over the period of 1995–2013. We identified four genetic clusters of which two northern ones showed demographic independence from the others. Trends in population size for the northwest subpopulation were statistically different from the other three genetic clusters and the northeast and southwest subpopulations demonstrated a general trend of increasing proportion of inactive leks over time. Population change from 1996 to 2012 suggested population growth in the southern subpopulations and decline, or neutral, change in the northern subpopulations. We suggest that sage-grouse subpopulations in northern Wyoming are at greater risk of extirpation than the southern subpopulations due to smaller census and effective population sizes and higher variability within subpopulations. Our research is an example of incorporating genetic and demographic data and provides guidance on the identification of subpopulations of conservation concern.

  5. Symbiotic Burkholderia Species Show Diverse Arrangements of nif/fix and nod Genes and Lack Typical High-Affinity Cytochrome cbb3 Oxidase Genes.

    Science.gov (United States)

    De Meyer, Sofie E; Briscoe, Leah; Martínez-Hidalgo, Pilar; Agapakis, Christina M; de-Los Santos, Paulina Estrada; Seshadri, Rekha; Reeve, Wayne; Weinstock, George; O'Hara, Graham; Howieson, John G; Hirsch, Ann M

    2016-08-01

    Genome analysis of fourteen mimosoid and four papilionoid beta-rhizobia together with fourteen reference alpha-rhizobia for both nodulation (nod) and nitrogen-fixing (nif/fix) genes has shown phylogenetic congruence between 16S rRNA/MLSA (combined 16S rRNA gene sequencing and multilocus sequence analysis) and nif/fix genes, indicating a free-living diazotrophic ancestry of the beta-rhizobia. However, deeper genomic analysis revealed a complex symbiosis acquisition history in the beta-rhizobia that clearly separates the mimosoid and papilionoid nodulating groups. Mimosoid-nodulating beta-rhizobia have nod genes tightly clustered in the nodBCIJHASU operon, whereas papilionoid-nodulating Burkholderia have nodUSDABC and nodIJ genes, although their arrangement is not canonical because the nod genes are subdivided by the insertion of nif and other genes. Furthermore, the papilionoid Burkholderia spp. contain duplications of several nod and nif genes. The Burkholderia nifHDKEN and fixABC genes are very closely related to those found in free-living diazotrophs. In contrast, nifA is highly divergent between both groups, but the papilionoid species nifA is more similar to alpha-rhizobia nifA than to other groups. Surprisingly, for all Burkholderia, the fixNOQP and fixGHIS genes required for cbb3 cytochrome oxidase production and assembly are missing. In contrast, symbiotic Cupriavidus strains have fixNOQPGHIS genes, revealing a divergence in the evolution of two distinct electron transport chains required for nitrogen fixation within the beta-rhizobia.

  6. An emperor penguin population estimate: the first global, synoptic survey of a species from space.

    Science.gov (United States)

    Fretwell, Peter T; Larue, Michelle A; Morin, Paul; Kooyman, Gerald L; Wienecke, Barbara; Ratcliffe, Norman; Fox, Adrian J; Fleming, Andrew H; Porter, Claire; Trathan, Phil N

    2012-01-01

    Our aim was to estimate the population of emperor penguins (Aptenodytes fosteri) using a single synoptic survey. We examined the whole continental coastline of Antarctica using a combination of medium resolution and Very High Resolution (VHR) satellite imagery to identify emperor penguin colony locations. Where colonies were identified, VHR imagery was obtained in the 2009 breeding season. The remotely-sensed images were then analysed using a supervised classification method to separate penguins from snow, shadow and guano. Actual counts of penguins from eleven ground truthing sites were used to convert these classified areas into numbers of penguins using a robust regression algorithm.We found four new colonies and confirmed the location of three previously suspected sites giving a total number of emperor penguin breeding colonies of 46. We estimated the breeding population of emperor penguins at each colony during 2009 and provide a population estimate of ~238,000 breeding pairs (compared with the last previously published count of 135,000-175,000 pairs). Based on published values of the relationship between breeders and non-breeders, this translates to a total population of ~595,000 adult birds.There is a growing consensus in the literature that global and regional emperor penguin populations will be affected by changing climate, a driver thought to be critical to their future survival. However, a complete understanding is severely limited by the lack of detailed knowledge about much of their ecology, and importantly a poor understanding of their total breeding population. To address the second of these issues, our work now provides a comprehensive estimate of the total breeding population that can be used in future population models and will provide a baseline for long-term research.

  7. An emperor penguin population estimate: the first global, synoptic survey of a species from space.

    Directory of Open Access Journals (Sweden)

    Peter T Fretwell

    Full Text Available Our aim was to estimate the population of emperor penguins (Aptenodytes fosteri using a single synoptic survey. We examined the whole continental coastline of Antarctica using a combination of medium resolution and Very High Resolution (VHR satellite imagery to identify emperor penguin colony locations. Where colonies were identified, VHR imagery was obtained in the 2009 breeding season. The remotely-sensed images were then analysed using a supervised classification method to separate penguins from snow, shadow and guano. Actual counts of penguins from eleven ground truthing sites were used to convert these classified areas into numbers of penguins using a robust regression algorithm.We found four new colonies and confirmed the location of three previously suspected sites giving a total number of emperor penguin breeding colonies of 46. We estimated the breeding population of emperor penguins at each colony during 2009 and provide a population estimate of ~238,000 breeding pairs (compared with the last previously published count of 135,000-175,000 pairs. Based on published values of the relationship between breeders and non-breeders, this translates to a total population of ~595,000 adult birds.There is a growing consensus in the literature that global and regional emperor penguin populations will be affected by changing climate, a driver thought to be critical to their future survival. However, a complete understanding is severely limited by the lack of detailed knowledge about much of their ecology, and importantly a poor understanding of their total breeding population. To address the second of these issues, our work now provides a comprehensive estimate of the total breeding population that can be used in future population models and will provide a baseline for long-term research.

  8. Evidence of population resistance to extreme low flows in a fluvial-dependent fish species

    Science.gov (United States)

    Katz, Rachel A.; Freeman, Mary C.

    2015-01-01

    Extreme low streamflows are natural disturbances to aquatic populations. Species in naturally intermittent streams display adaptations that enhance persistence during extreme events; however, the fate of populations in perennial streams during unprecedented low-flow periods is not well-understood. Biota requiring swift-flowing habitats may be especially vulnerable to flow reductions. We estimated the abundance and local survival of a native fluvial-dependent fish species (Etheostoma inscriptum) across 5 years encompassing historic low flows in a sixth-order southeastern USA perennial river. Based on capturemark-recapture data, the study shoal may have acted as a refuge during severe drought, with increased young-of-the-year (YOY) recruitment and occasionally high adult immigration. Contrary to expectations, summer and autumn survival rates (30 days) were not strongly depressed during low-flow periods, despite 25%-80% reductions in monthly discharge. Instead, YOY survival increased with lower minimum discharge and in response to small rain events that increased low-flow variability. Age-1+ fish showed the opposite pattern, with survival decreasing in response to increasing low-flow variability. Results from this population dynamics study of a small fish in a perennial river suggest that fluvial-dependent species can be resistant to extreme flow reductions through enhanced YOY recruitment and high survival

  9. Dispersal capacity predicts both population genetic structure and species richness in reef fishes.

    Science.gov (United States)

    Riginos, Cynthia; Buckley, Yvonne M; Blomberg, Simon P; Treml, Eric A

    2014-07-01

    Dispersal is a fundamental species characteristic that should directly affect both rates of gene flow among spatially distributed populations and opportunities for speciation. Yet no single trait associated with dispersal has been demonstrated to affect both micro- and macroevolutionary patterns of diversity across a diverse biological assemblage. Here, we examine patterns of genetic differentiation and species richness in reef fishes, an assemblage of over 7,000 species comprising approximately one-third of the extant bony fishes and over one-tenth of living vertebrates. In reef fishes, dispersal occurs primarily during a planktonic larval stage. There are two major reproductive and parental investment syndromes among reef fishes, and the differences between them have implications for dispersal: (1) benthic guarding fishes lay negatively buoyant eggs, typically guarded by the male parent, and from these eggs hatch large, strongly swimming larvae; in contrast, (2) pelagic spawning fishes release small floating eggs directly into the water column, which drift unprotected before small weakly swimming larvae hatch. Using phylogenetic comparative methods, we show that benthic guarders have significantly greater population structure than pelagic spawners and additionally that taxonomic families of benthic guarders are more species rich than families of pelagic spawners. Our findings provide a compelling case for the continuity between micro- and macroevolutionary processes of biological diversification and underscore the importance of dispersal-related traits in influencing the mode and tempo of evolution.

  10. Fish population studies using parasites from the Southeastern Pacific Ocean: considering host population changes and species body size as sources of variability of parasite communities.

    Science.gov (United States)

    George-Nascimento, Mario; Oliva, Marcelo

    2015-01-01

    Research using parasites in fish population studies in the South Eastern Pacific (SEP) is summarized. There are 27 such studies (snapshots mainly) in single host species sampled at different geographic localities and at somewhat similar times. They have been devoted mainly to economically important species, though others on coastal and intertidal fish or on less- or non-commercial species provide insights on scales of temporal and spatial variation of parasite infracommunities. Later, we assess whether the probability of harbouring parasites depends on the host species body size. Our results indicate that a stronger tool for fish population studies may be developed under regular (long term) scrutiny of parasite communities, especially of small fish host species, due to their larger variability in richness, abundance and total biomass, than in large fish species. Finally, it might also be necessary to consider the effects of fishing on parasite communities as well as the natural oscillations (coupled or not) of host and parasite populations.

  11. Demography of a reintroduced population: moving toward management models for an endangered species, the whooping crane

    Science.gov (United States)

    Servanty, Sabrina; Converse, Sarah J.; Bailey, Larissa L.

    2014-01-01

    The reintroduction of threatened and endangered species is now a common method for reestablishing populations. Typically, a fundamental objective of reintroduction is to establish a self-sustaining population. Estimation of demographic parameters in reintroduced populations is critical, as these estimates serve multiple purposes. First, they support evaluation of progress toward the fundamental objective via construction of population viability analyses (PVAs) to predict metrics such as probability of persistence. Second, PVAs can be expanded to support evaluation of management actions, via management modeling. Third, the estimates themselves can support evaluation of the demographic performance of the reintroduced population, e.g., via comparison with wild populations. For each of these purposes, thorough treatment of uncertainties in the estimates is critical. Recently developed statistical methods - namely, hierarchical Bayesian implementations of state-space models - allow for effective integration of different types of uncertainty in estimation. We undertook a demographic estimation effort for a reintroduced population of endangered whooping cranes with the purpose of ultimately developing a Bayesian PVA for determining progress toward establishing a self-sustaining population, and for evaluating potential management actions via a Bayesian PVA-based management model. We evaluated individual and temporal variation in demographic parameters based upon a multi-state mark-recapture model. We found that survival was relatively high across time and varied little by sex. There was some indication that survival varied by release method. Survival was similar to that observed in the wild population. Although overall reproduction in this reintroduced population is poor, birds formed social pairs when relatively young, and once a bird was in a social pair, it had a nearly 50% chance of nesting the following breeding season. Also, once a bird had nested, it had a high

  12. Comparing climate change and species invasions as drivers of coldwater fish population extirpations.

    Science.gov (United States)

    Sharma, Sapna; Vander Zanden, M Jake; Magnuson, John J; Lyons, John

    2011-01-01

    Species are influenced by multiple environmental stressors acting simultaneously. Our objective was to compare the expected effects of climate change and invasion of non-indigenous rainbow smelt (Osmerus mordax) on cisco (Coregonus artedii) population extirpations at a regional level. We assembled a database of over 13,000 lakes in Wisconsin, USA, summarising fish occurrence, lake morphology, water chemistry, and climate. We used A1, A2, and B1 scenarios from the Intergovernmental Panel on Climate Change (IPCC) of future temperature conditions for 15 general circulation models in 2046-2065 and 2081-2100 totalling 78 projections. Logistic regression indicated that cisco tended to occur in cooler, larger, and deeper lakes. Depending upon the amount of warming, 25-70% of cisco populations are predicted to be extirpated by 2100. In addition, cisco are influenced by the invasion of rainbow smelt, which prey on young cisco. Projecting current estimates of rainbow smelt spread and impact into the future will result in the extirpation of about 1% of cisco populations by 2100 in Wisconsin. Overall, the effect of climate change is expected to overshadow that of species invasion as a driver of coldwater fish population extirpations. Our results highlight the potentially dominant role of climate change as a driver of biotic change.

  13. Comparing climate change and species invasions as drivers of coldwater fish population extirpations.

    Directory of Open Access Journals (Sweden)

    Sapna Sharma

    Full Text Available Species are influenced by multiple environmental stressors acting simultaneously. Our objective was to compare the expected effects of climate change and invasion of non-indigenous rainbow smelt (Osmerus mordax on cisco (Coregonus artedii population extirpations at a regional level. We assembled a database of over 13,000 lakes in Wisconsin, USA, summarising fish occurrence, lake morphology, water chemistry, and climate. We used A1, A2, and B1 scenarios from the Intergovernmental Panel on Climate Change (IPCC of future temperature conditions for 15 general circulation models in 2046-2065 and 2081-2100 totalling 78 projections. Logistic regression indicated that cisco tended to occur in cooler, larger, and deeper lakes. Depending upon the amount of warming, 25-70% of cisco populations are predicted to be extirpated by 2100. In addition, cisco are influenced by the invasion of rainbow smelt, which prey on young cisco. Projecting current estimates of rainbow smelt spread and impact into the future will result in the extirpation of about 1% of cisco populations by 2100 in Wisconsin. Overall, the effect of climate change is expected to overshadow that of species invasion as a driver of coldwater fish population extirpations. Our results highlight the potentially dominant role of climate change as a driver of biotic change.

  14. Geographical parthenogenesis and population genetic structure in the alpine species Ranunculus kuepferi (Ranunculaceae).

    Science.gov (United States)

    Cosendai, A-C; Wagner, J; Ladinig, U; Rosche, C; Hörandl, E

    2013-06-01

    Geographical parthenogenesis describes the enigmatic phenomenon that asexual organisms have larger distribution areas than their sexual relatives, especially in previously glaciated areas. Classical models suggest temporary advantages to asexuality in colonization scenarios because of uniparental reproduction and clonality. We analyzed population genetic structure and self-fertility of the plant species Ranunculus kuepferi on 59 populations from the whole distribution area (European Alps, Apennines and Corsica). Amplified fragment length polymorphisms (AFLPs) and five microsatellite loci revealed individual genotypes for all populations and mostly insignificant differences between diploid sexuals and tetraploid apomicts in all measures of genetic diversity. Low frequencies of private AFLP fragments/simple sequence repeat alleles, and character incompatibility analyses suggest that facultative recombination explains best the unexpectedly high genotypic diversity of apomicts. STRUCTURE analyses using AFLPs revealed a higher number of partitions and a stronger geographical subdivision for diploids than for tetraploids, which contradicts expectations of standard gene flow models, but indicates a reduction of genetic structure in asexuals. Apomictic populations exhibited high admixture near the sexual area, but appeared rather uniform in remote areas. Bagging experiments and analyses of pollen tube growth confirmed self-fertility for pollen-dependent apomicts, but self-sterility for diploid sexuals. Facultative apomixis combines advantages of both modes of reproduction: uniparental reproduction allows for rapid colonization of remote areas, whereas facultative sexuality and polyploidy maintains genetic diversity within apomictic populations. The density dependence of outcrossing limits range expansions of sexual populations.

  15. Geographical parthenogenesis and population genetic structure in the alpine species Ranunculus kuepferi (Ranunculaceae)

    Science.gov (United States)

    Cosendai, A-C; Wagner, J; Ladinig, U; Rosche, C; Hörandl, E

    2013-01-01

    Geographical parthenogenesis describes the enigmatic phenomenon that asexual organisms have larger distribution areas than their sexual relatives, especially in previously glaciated areas. Classical models suggest temporary advantages to asexuality in colonization scenarios because of uniparental reproduction and clonality. We analyzed population genetic structure and self-fertility of the plant species Ranunculus kuepferi on 59 populations from the whole distribution area (European Alps, Apennines and Corsica). Amplified fragment length polymorphisms (AFLPs) and five microsatellite loci revealed individual genotypes for all populations and mostly insignificant differences between diploid sexuals and tetraploid apomicts in all measures of genetic diversity. Low frequencies of private AFLP fragments/simple sequence repeat alleles, and character incompatibility analyses suggest that facultative recombination explains best the unexpectedly high genotypic diversity of apomicts. STRUCTURE analyses using AFLPs revealed a higher number of partitions and a stronger geographical subdivision for diploids than for tetraploids, which contradicts expectations of standard gene flow models, but indicates a reduction of genetic structure in asexuals. Apomictic populations exhibited high admixture near the sexual area, but appeared rather uniform in remote areas. Bagging experiments and analyses of pollen tube growth confirmed self-fertility for pollen-dependent apomicts, but self-sterility for diploid sexuals. Facultative apomixis combines advantages of both modes of reproduction: uniparental reproduction allows for rapid colonization of remote areas, whereas facultative sexuality and polyploidy maintains genetic diversity within apomictic populations. The density dependence of outcrossing limits range expansions of sexual populations. PMID:23403961

  16. Projected risk of population declines for native fish species in the Upper Mississippi River

    Science.gov (United States)

    Crimmins, S.M.; Boma, P.; Thogmartin, W.E.

    2015-01-01

    Conservationists are in need of objective metrics for prioritizing the management of habitats. For individual species, the threat of extinction is often used to prioritize what species are in need of conservation action. Using long-term monitoring data, we applied a Bayesian diffusion approximation to estimate quasi-extinction risk for 54 native fish species within six commercial navigation reaches along a 1350-km gradient of the upper Mississippi River system. We found a strong negative linear relationship between quasi-extinction risk and distance upstream. For some species, quasi-extinction estimates ranged from nearly zero in some reaches to one in others, suggesting substantial variability in threats facing individual river reaches. We found no evidence that species traits affected quasi-extinction risk across the entire system. Our results indicate that fishes within the upper Mississippi River system face localized threats that vary across river impact gradients. This suggests that conservation actions should be focused on local habitat scales but should also consider the additive effects on downstream conditions. We also emphasize the need for identification of proximate mechanisms behind observed and predicted population declines, as conservation actions will require mitigation of such mechanisms. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

  17. Chemical Variation in a Dominant Tree Species: Population Divergence, Selection and Genetic Stability across Environments

    Science.gov (United States)

    O’Reilly-Wapstra, Julianne M.; Miller, Alison M.; Hamilton, Matthew G.; Williams, Dean; Glancy-Dean, Naomi; Potts, Brad M.

    2013-01-01

    Understanding among and within population genetic variation of ecologically important plant traits provides insight into the potential evolutionary processes affecting those traits. The strength and consistency of selection driving variability in traits would be affected by plasticity in differences among genotypes across environments (G×E). We investigated population divergence, selection and environmental plasticity of foliar plant secondary metabolites (PSMs) in a dominant tree species, Eucalyptus globulus. Using two common garden trials we examined variation in PSMs at multiple genetic scales; among 12 populations covering the full geographic range of the species and among up to 60 families within populations. Significant genetic variation in the expression of many PSMs resides both among and within populations of E. globulus with moderate (e.g., sideroxylonal A h2op = 0.24) to high (e.g., macrocarpal G h2op = 0.48) narrow sense heritabilities and high coefficients of additive genetic variation estimated for some compounds. A comparison of Qst and Fst estimates suggest that variability in some of these traits may be due to selection. Importantly, there was no genetic by environment interaction in the expression of any of the quantitative chemical traits despite often significant site effects. These results provide evidence that natural selection has contributed to population divergence in PSMs in E. globulus, and identifies the formylated phloroglucinol compounds (particularly sideroxylonal) and a dominant oil, 1,8-cineole, as candidates for traits whose genetic architecture has been shaped by divergent selection. Additionally, as the genetic differences in these PSMs that influence community phenotypes is stable across environments, the role of plant genotype in structuring communities is strengthened and these genotypic differences may be relatively stable under global environmental changes. PMID:23526981

  18. Chemical variation in a dominant tree species: population divergence, selection and genetic stability across environments.

    Directory of Open Access Journals (Sweden)

    Julianne M O'Reilly-Wapstra

    Full Text Available Understanding among and within population genetic variation of ecologically important plant traits provides insight into the potential evolutionary processes affecting those traits. The strength and consistency of selection driving variability in traits would be affected by plasticity in differences among genotypes across environments (G×E. We investigated population divergence, selection and environmental plasticity of foliar plant secondary metabolites (PSMs in a dominant tree species, Eucalyptus globulus. Using two common garden trials we examined variation in PSMs at multiple genetic scales; among 12 populations covering the full geographic range of the species and among up to 60 families within populations. Significant genetic variation in the expression of many PSMs resides both among and within populations of E. globulus with moderate (e.g., sideroxylonal A h(2op = 0.24 to high (e.g., macrocarpal G h(2op = 0.48 narrow sense heritabilities and high coefficients of additive genetic variation estimated for some compounds. A comparison of Qst and Fst estimates suggest that variability in some of these traits may be due to selection. Importantly, there was no genetic by environment interaction in the expression of any of the quantitative chemical traits despite often significant site effects. These results provide evidence that natural selection has contributed to population divergence in PSMs in E. globulus, and identifies the formylated phloroglucinol compounds (particularly sideroxylonal and a dominant oil, 1,8-cineole, as candidates for traits whose genetic architecture has been shaped by divergent selection. Additionally, as the genetic differences in these PSMs that influence community phenotypes is stable across environments, the role of plant genotype in structuring communities is strengthened and these genotypic differences may be relatively stable under global environmental changes.

  19. Combining demographic and genetic factors to assess population vulnerability in stream species

    Science.gov (United States)

    Erin L, Landguth; Muhlfeld, Clint C.; Jones, Leslie W.; Waples, Robin S.; Whited, Diane; Lowe, Winsor H.; Lucotch, John; Neville, Helen; Luikart, Gordon

    2014-01-01

    Accelerating climate change and other cumulative stressors create an urgent need to understand the influence of environmental variation and landscape features on the connectivity and vulnerability of freshwater species. Here, we introduce a novel modeling framework for aquatic systems that integrates spatially explicit, individual-based, demographic and genetic (demogenetic) assessments with environmental variables. To show its potential utility, we simulated a hypothetical network of 19 migratory riverine populations (e.g., salmonids) using a riverscape connectivity and demogenetic model (CDFISH). We assessed how stream resistance to movement (a function of water temperature, fluvial distance, and physical barriers) might influence demogenetic connectivity, and hence, population vulnerability. We present demographic metrics (abundance, immigration, and change in abundance) and genetic metrics (diversity, differentiation, and change in differentiation), and combine them into a single vulnerability index for identifying populations at risk of extirpation. We considered four realistic scenarios that illustrate the relative sensitivity of these metrics for early detection of reduced connectivity: (1) maximum resistance due to high water temperatures throughout the network, (2) minimum resistance due to low water temperatures throughout the network, (3) increased resistance at a tributary junction caused by a partial barrier, and (4) complete isolation of a tributary, leaving resident individuals only. We then applied this demogenetic framework using empirical data for a bull trout (Salvelinus confluentus) metapopulation in the upper Flathead River system, Canada and USA, to assess how current and predicted future stream warming may influence population vulnerability. Results suggest that warmer water temperatures and associated barriers to movement (e.g., low flows, dewatering) are predicted to fragment suitable habitat for migratory salmonids, resulting in the loss

  20. Post-Glacial Expansion and Population Genetic Divergence of Mangrove Species Avicennia germinans (L.) Stearn and Rhizophora mangle L. along the Mexican Coast

    Science.gov (United States)

    Sandoval-Castro, Eduardo; Dodd, Richard S.; Riosmena-Rodríguez, Rafael; Enríquez-Paredes, Luis Manuel; Tovilla-Hernández, Cristian; López-Vivas, Juan Manuel; Aguilar-May, Bily; Muñiz-Salazar, Raquel

    2014-01-01

    Mangrove forests in the Gulf of California, Mexico represent the northernmost populations along the Pacific coast and thus they are likely to be source populations for colonization at higher latitudes as climate becomes more favorable. Today, these populations are relatively small and fragmented and prior research has indicated that they are poor in genetic diversity. Here we set out to investigate whether the low diversity in this region was a result of recent colonization, or fragmentation and genetic drift of once more extensive mangroves due to climatic changes in the recent past. By sampling the two major mangrove species, Rhizophora mangle and Avicennia germinans, along the Pacific and Atlantic coasts of Mexico, we set out to test whether concordant genetic signals could elucidate recent evolution of the ecosystem. Genetic diversity of both mangrove species showed a decreasing trend toward northern latitudes along the Pacific coast. The lowest levels of genetic diversity were found at the range limits around the Gulf of California and the outer Baja California peninsula. Lack of a strong spatial genetic structure in this area and recent northern gene flow in A. germinans suggest recent colonization by this species. On the other hand, lack of a signal of recent northern dispersal in R. mangle, despite the higher dispersal capability of this species, indicates a longer presence of populations, at least in the southern Gulf of California. We suggest that the longer history, together with higher genetic diversity of R. mangle at the range limits, likely provides a gene pool better able to colonize northwards under climate change than A. germinans. PMID:24699389

  1. Post-glacial expansion and population genetic divergence of mangrove species Avicennia germinans (L.) Stearn and Rhizophora mangle L. along the Mexican coast.

    Science.gov (United States)

    Sandoval-Castro, Eduardo; Dodd, Richard S; Riosmena-Rodríguez, Rafael; Enríquez-Paredes, Luis Manuel; Tovilla-Hernández, Cristian; López-Vivas, Juan Manuel; Aguilar-May, Bily; Muñiz-Salazar, Raquel

    2014-01-01

    Mangrove forests in the Gulf of California, Mexico represent the northernmost populations along the Pacific coast and thus they are likely to be source populations for colonization at higher latitudes as climate becomes more favorable. Today, these populations are relatively small and fragmented and prior research has indicated that they are poor in genetic diversity. Here we set out to investigate whether the low diversity in this region was a result of recent colonization, or fragmentation and genetic drift of once more extensive mangroves due to climatic changes in the recent past. By sampling the two major mangrove species, Rhizophora mangle and Avicennia germinans, along the Pacific and Atlantic coasts of Mexico, we set out to test whether concordant genetic signals could elucidate recent evolution of the ecosystem. Genetic diversity of both mangrove species showed a decreasing trend toward northern latitudes along the Pacific coast. The lowest levels of genetic diversity were found at the range limits around the Gulf of California and the outer Baja California peninsula. Lack of a strong spatial genetic structure in this area and recent northern gene flow in A. germinans suggest recent colonization by this species. On the other hand, lack of a signal of recent northern dispersal in R. mangle, despite the higher dispersal capability of this species, indicates a longer presence of populations, at least in the southern Gulf of California. We suggest that the longer history, together with higher genetic diversity of R. mangle at the range limits, likely provides a gene pool better able to colonize northwards under climate change than A. germinans.

  2. Fasciola hepatica demonstrates high levels of genetic diversity, a lack of population structure and high gene flow: possible implications for drug resistance.

    Science.gov (United States)

    Beesley, Nicola J; Williams, Diana J L; Paterson, Steve; Hodgkinson, Jane

    2017-01-01

    Fasciola hepatica, the liver fluke, is a trematode parasite of considerable economic importance to the livestock industry and is a re-emerging zoonosis that poses a risk to human health in F. hepatica-endemic areas worldwide. Drug resistance is a substantial threat to the current and future control of F. hepatica, yet little is known about how the biology of the parasite influences the development and spread of resistance. Given that F. hepatica can self-fertilise and therefore inbreed, there is the potential for greater population differentiation and an increased likelihood of recessive alleles, such as drug resistance genes, coming together. This could be compounded by clonal expansion within the snail intermediate host and aggregation of parasites of the same genotype on pasture. Alternatively, widespread movement of animals that typically occurs in the UK could promote high levels of gene flow and prevent population differentiation. We identified clonal parasites with identical multilocus genotypes in 61% of hosts. Despite this, 84% of 1579 adult parasites had unique multilocus genotypes, which supports high levels of genotypic diversity within F. hepatica populations. Our analyses indicate a selfing rate no greater than 2%, suggesting that this diversity is in part due to the propensity for F. hepatica to cross-fertilise. Finally, although we identified high genetic diversity within a given host, there was little evidence for differentiation between populations from different hosts, indicating a single panmictic population. This implies that, once those emerge, anthelmintic resistance genes have the potential to spread rapidly through liver fluke populations. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. Genetic population structure of the desert shrub species lycium ruthenicum inferred from chloroplast dna

    International Nuclear Information System (INIS)

    Chen, H.; Yonezawa, T.

    2014-01-01

    Lycium ruthenicum (Solananeae), a spiny shrub mostly distributed in the desert regions of north and northwest China, has been shown to exhibit high tolerance to the extreme environment. In this study, the phylogeography and evolutionary history of L. ruthenicum were examined, on the basis of 80 individuals from eight populations. Using the sequence variations of two spacer regions of chloroplast DNA (trnH-psbA and rps16-trnK) , the absence of a geographic component in the chloroplast DNA genetic structure was identified (GST = 0.351, NST = 0.304, NST< GST), which was consisted with the result of SAMOVA, suggesting weak phylogeographic structure of this species. Phylogenetic and network analyses showed that a total of 10 haplotypes identified in the present study clustered into two clades, in which clade I harbored the ancestral haplotypes that inferred two independent glacial refugia in the middle of Qaidam Basin and the western Inner Mongolia. The existence of regional evolutionary differences was supported by GENETREE, which revealed that one of the population in Qaidam Basin and the two populations in Tarim Basin had experienced rapid expansion, and the other populations retained relatively stable population size during the Pleistocene . Given the results of long-term gene flow and pairwise differences, strong gene flow was insufficient to reduce the genetic differentiation among populations or within populations, probably due to the genetic composition containing a common haplotype and the high number of private haplotypes fixed for most of the population. The divergence times of different lineages were consistent with the rapid uplift phases of the Qinghai-Tibetan Plateau and the initiation and expansion of deserts in northern China, suggesting that the origin and evolution of L. ruthenicum were strongly influenced by Quaternary environment changes. (author)

  4. Baseline Susceptibility of Field Populations of Helicoverpa armigera to Bacillus thuringiensis Vip3Aa Toxin and Lack of Cross-Resistance between Vip3Aa and Cry Toxins

    Directory of Open Access Journals (Sweden)

    Yiyun Wei

    2017-04-01

    Full Text Available The cotton bollworm Helicoverpa armigera (Hübner is one of the most damaging cotton pests worldwide. In China, control of this pest has been dependent on transgenic cotton producing a single Bacillus thuringiensis (Bt protein Cry1Ac since 1997. A small, but significant, increase in H. armigera resistance to Cry1Ac was detected in field populations from Northern China. Since Vip3Aa has a different structure and mode of action than Cry proteins, Bt cotton pyramids containing Vip3Aa are considered as ideal successors of Cry1Ac cotton in China. In this study, baseline susceptibility of H. armigera to Vip3Aa was evaluated in geographic field populations collected in 2014 from major cotton-producing areas of China. The LC50 values of 12 field populations ranged from 0.053 to 1.311 μg/cm2, representing a 25-fold range of natural variation among populations. It is also demonstrated that four laboratory strains of H. armigera with high levels of resistance to Cry1Ac or Cry2Ab have no cross-resistance to Vip3Aa protein. The baseline susceptibility data established here will serve as a comparative reference for detection of field-evolved resistance to Vip3Aa in H. armigera after future deployment of Bt cotton pyramids in China.

  5. Lack of association between rs1800795 (-174 G/C polymorphism in the promoter region of interleukin-6 gene and susceptibility to type 2 diabetes in Isfahan population

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    Reza Ghavimi

    2016-01-01

    Conclusion: These results indicated that the rs1800795 SNP is not a susceptibility gene variant for the development of T2DM in the Isfahan population. Further studies using new data on complex transcriptional interactions between IL-6 polymorphic sites are necessary to determine IL-6 haplotype influence on susceptibility to T2DM.

  6. Population resources of an endangered species Salix lapponum L. in Polesie Lubelskie Region (eastern Poland

    Directory of Open Access Journals (Sweden)

    Magdalena Pogorzelec

    2014-12-01

    Full Text Available This research, carried out in the years 2011–2013, aimed to evaluate Salix lapponum stands in the peat bogs of Polesie Lubelskie Region as well as to determine the condition of the population and the changes that have taken place since the 1950’s. An inventory carried out in 25 stands of S. lapponum known from the literature shows that the number of its stands has decreased by 80% in Polesie Lubelskie Region. In all the confirmed locations, a decrease in population numbers was also found in relation to the data known from the literature since the 1950’s. In the majority of the population locations that were considered to be extinct, there were no significant changes in habitat conditions, and ecological succession and changes in hydrological conditions could have been the cause of habitat changes only at a few sites. In the light of the study, the preservation of the S. lapponum population in Polesie Lubelskie seems to be impossible if appropriate active conservation measures are not taken immediately. Because area-based conservation, which covers most of the habitats of the studied species, does not bring the expected results, the possibility of ex situ conservation and enlargement of the populations existing in the natural environment in peat bog ecosystems in Polesie should be explored.

  7. Character-based, population-level DNA barcoding in Mexican species of Zamia L. (Zamiaceae: Cycadales).

    Science.gov (United States)

    Nicolalde-Morejón, Fernando; Vergara-Silva, Francisco; González-Astorga, Jorge; Stevenson, Dennis W

    2010-12-01

    With the recent proposal of matK and rbcL as core plant DNA barcoding regions by the Consortium for the Barcoding of Life Plant Working Group, the construction of reference libraries in the botanical DNA barcoding initiative has entered a new phase. However, in a recent DNA barcoding study in the three Mexican genera of the gymnosperm order Cycadales, we found that neither matK nor rbcL allow high levels of molecular identification of previously established species. Our data analysis in that study rested on the "Characteristic Attributes Organization System" (CAOS), a character-based algorithm for the definition of "DNA diagnostics." Here, we use CAOS to analyze a population-level molecular data set in Zamia, one of the three cycad genera occurring in Mexico, whose populations display contrasting biogeographic patterns. Our population-level study, which includes all species in the region formally known as Megamexico, is restricted to the genome region, which showed the best single-locus molecular identification performance in our previous study-namely, the noncoding intergenic chloroplast spacer psbK-I. Our comparison of single-individual vs. population-level psbK-I datasets in Zamia indicates that CAOS analyses are sensitive to slight alignment changes, which in turn derive from the different amounts of molecular variation present in each matrix type. We, therefore, suggest that character-based studies that involve population-level data should contemplate this type of comparison between data matrices, before a set of DNA diagnostics in a given DNA barcoding reference library is considered definitive.

  8. Alpine glacial relict species losing out to climate change: The case of the fragmented mountain hare population (Lepus timidus) in the Alps.

    Science.gov (United States)

    Rehnus, Maik; Bollmann, Kurt; Schmatz, Dirk R; Hackländer, Klaus; Braunisch, Veronika

    2018-03-13

    Alpine and Arctic species are considered to be particularly vulnerable to climate change, which is expected to cause habitat loss, fragmentation and-ultimately-extinction of cold-adapted species. However, the impact of climate change on glacial relict populations is not well understood, and specific recommendations for adaptive conservation management are lacking. We focused on the mountain hare (Lepus timidus) as a model species and modelled species distribution in combination with patch and landscape-based connectivity metrics. They were derived from graph-theory models to quantify changes in species distribution and to estimate the current and future importance of habitat patches for overall population connectivity. Models were calibrated based on 1,046 locations of species presence distributed across three biogeographic regions in the Swiss Alps and extrapolated according to two IPCC scenarios of climate change (RCP 4.5 & 8.5), each represented by three downscaled global climate models. The models predicted an average habitat loss of 35% (22%-55%) by 2100, mainly due to an increase in temperature during the reproductive season. An increase in habitat fragmentation was reflected in a 43% decrease in patch size, a 17% increase in the number of habitat patches and a 34% increase in inter-patch distance. However, the predicted changes in habitat availability and connectivity varied considerably between biogeographic regions: Whereas the greatest habitat losses with an increase in inter-patch distance were predicted at the southern and northern edges of the species' Alpine distribution, the greatest increase in patch number and decrease in patch size is expected in the central Swiss Alps. Finally, both the number of isolated habitat patches and the number of patches crucial for maintaining the habitat network increased under the different variants of climate change. Focusing conservation action on the central Swiss Alps may help mitigate the predicted effects of

  9. Combinations of bacterial species associated with symptomatic endodontic infections in a Chinese population.

    Science.gov (United States)

    Qi, Z; Cao, H; Jiang, H; Zhao, J; Tang, Z

    2016-01-01

    To use microarrays to detect 11 selected bacteria in infected root canals, revealing bacterial combinations that are associated with clinical symptoms and signs of primary endodontic infections in a Chinese population. DNA was extracted from 90 samples collected from the root canals of teeth with primary endodontic infections in a Chinese population, and the 16S rRNA gene was amplified by polymerase chain reaction (PCR). The PCR products were hybridized to microarrays containing specific oligonucleotide probes targeting 11 species, and the arrays were screened with a confocal laser scanner. Pearson's chi-squared test and cluster analysis were performed to investigate the associations between the bacterial combinations and clinical symptoms and signs using SAS 8.02. Seventy-seven samples (86%) yielded at least one of the 11 target species. Parvimonas micra (56%), Porphyromonas endodontalis (51%), Tannerella forsythia (48%), Prevotella intermedia (44%) and Porphyromonas gingivalis (37%) were the most prevalent taxa and were often concomitant. The following positive associations were found between the bacterial combinations and clinical features: P. endodontalis and T. forsythia with abscess; P. gingivalis and P. micra with sinus tract; P. gingivalis and P. endodontalis or P. micra and P. endodontalis with abscess and sinus tract; and the combination of P. endodontalis, P. micra, T. forsythia and P. gingivalis with sinus tract (P endodontic origin with bacterial synergism in a Chinese population. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  10. Lack of Association between Missense Variants in GRHL3 (rs2486668 and rs545809 and Susceptibility to Non-Syndromic Orofacial Clefts in a Han Chinese Population.

    Directory of Open Access Journals (Sweden)

    Miao He

    Full Text Available Grainyhead-like-3 (GRHL3 was recently identified as the second gene that, when mutated, can leads to Van der Woude syndrome, which is characterized by orofacial clefts (OFC and lower lip pits. In addition, a missense variant (rs41268753 in GRHL3 confers risk for non-syndromic cleft palate cases of European ancestry. Together with interferon regulatory factor 6 (IRF6, GRHL3 may be associated with the risk of NSOFC which awaits for being verified across different ethnic populations.The aim of this study was to investigate the possible relationship between common functional variants in GRHL3 and susceptibility to NSOFC, especially cleft palate cases, in a Han Chinese population, one of the ethnic groups with the highest birth prevalence of orofacial clefting.Because the allele frequency for rs41268753 minor alleles was zero in our Chinese population, we selected functional single nucleotide polymorphisms (SNPs spanning GRHL3 with minor allele frequencies (MAFs > 5% in the Han Chinese population. Two SNPs which meet the above criteria were then genotyped in a case-control cohort comprising 1145 individuals using the TaqMan 5'-exonuclease allelic discrimination assay.SNPs rs2486668 and rs545809 were used in this study. Overall genotype and allele distributions of both SNPs in general and stratified genotyping analyses revealed no statistically significant differences between cases and controls. Further logistic regression analyses using different genetic models failed to reveal any evidence that these markers influence risk to NSOFC.The variant rs41268753 in GRHL3 increases the risk for cleft palate in European population, but our findings failed to detect the link between two GRHL3 SNPs (rs2486668 and rs545809 and risk to NSOFC in the Han Chinese cohort. Although the present study did not provide any evidence that common functional variants in GRHL3 may contribute to NSOFC etiology in this Chinese population, further studies with a larger sample

  11. Lack of Association between Human µ-Opioid Receptor (OPRM1 Gene Polymorphisms and Heroin Addiction in A Sample of Southeast Iranian Population

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    Mansour Shakiba

    2017-06-01

    Full Text Available It has been proposed that genetic factors account for 30%–50% of the risk for cocaine and heroin addiction. The present study was aimed to find out the impact of µ-opioid receptor gene (OPRM1 rs1799971 A > G and rs9479757 polymorphisms on heroin dependence in a sample of southeast Iranian population. This case-control study was done on 123 heroin addicts and 140 non-addicts Iranian male. Genomic DNA was extracted from peripheral blood cells using salting out method. Genotyping of OPRM1 rs1799971 and rs9479757 polymorphisms were performed using PCR-RFLP method. Overall, our results did not support an association between OPRM1 variants and risk of heroin dependence in a sample of southeast Iranian population. Further studies with larges sample sizes and different ethnicities are required to validate our findings.

  12. Global population structure and taxonomy of the wandering albatross species complex.

    Science.gov (United States)

    Burg, T M; Croxall, J P

    2004-08-01

    A recent taxonomic revision of wandering albatross elevated each of the four subspecies to species. We used mitochondrial DNA and nine microsatellite markers to study the phylogenetic relationships of three species (Diomedea antipodensis, D. exulans and D. gibsoni) in the wandering albatross complex. A small number of samples from a fourth species, D. dabbenena, were analysed using mitochondrial DNA only. Mitochondrial DNA sequence analyses indicated the presence of three distinct groups within the wandering albatross complex: D. exulans, D. dabbenena and D. antipodensis/D. gibsoni. Although no fixed differences were found between D. antipodensis and D. gibsoni, a significant difference in the frequency of a single restriction site was detected using random fragment length polymorphism. Microsatellite analyses using nine variable loci, showed that D. exulans, D. antipodensis and D. gibsoni were genetically differentiated. Despite the widespread distribution of D. exulans, we did not detect any genetic differentiation among populations breeding on different island groups. The lower level of genetic differentiation between D. antipodensis and D. gibsoni should be reclassified as D. antipodensis. Within the context of the current taxonomy, these combined data support three species: D. dabbenena, D. exulans and D. antipodensis. Copyright 2004 Blackwell Publishing Ltd

  13. Lack of association of interferon regulatory factor 1 with severe malaria in affected child-parental trio studies across three African populations.

    Directory of Open Access Journals (Sweden)

    Valentina D Mangano

    Full Text Available Interferon Regulatory Factor 1 (IRF-1 is a member of the IRF family of transcription factors, which have key and diverse roles in the gene-regulatory networks of the immune system. IRF-1 has been described as a critical mediator of IFN-gamma signalling and as the major player in driving TH1 type responses. It is therefore likely to be crucial in both innate and adaptive responses against intracellular pathogens such as Plasmodium falciparum. Polymorphisms at the human IRF1 locus have been previously found to be associated with the ability to control P. falciparum infection in populations naturally exposed to malaria. In order to test whether genetic variation at the IRF1 locus also affects the risk of developing severe malaria, we performed a family-based test of association for 18 Single Nucleotide Polymorphisms (SNPs across the gene in three African populations, using genotype data from 961 trios consisting of one affected child and his/her two parents (555 from The Gambia, 204 from Kenya and 202 from Malawi. No significant association with severe malaria or severe malaria subphenotypes (cerebral malaria and severe malaria anaemia was observed for any of the SNPs/haplotypes tested in any of the study populations. Our results offer no evidence that the molecular pathways regulated by the transcription factor IRF-1 are involved in the immune-based pathogenesis of severe malaria.

  14. Population Genetics of the Endemic Hawaiian Species Chrysodracon hawaiiensis and Chrysodracon auwahiensis (Asparagaceae: Insights from RAPD and ISSR Variation

    Directory of Open Access Journals (Sweden)

    Pei-Luen Lu

    2016-08-01

    Full Text Available The genus Chrysodracon has six endemic species in the Hawaii Islands. Chrysodracon hawaiiensis is endemic to Hawaii Island and was described as a distinct species in 1980. It was listed as an endangered species on the International Union for the Conservation of Nature and Natural Resources (IUCN Red List in 1997. This woody plant species was, at one time, common in exposed dry forests, but it became very rare due to grazing pressure and human development. The tree species Chrysodracon auwahiensis (C. auwahiensis, endemic to Maui and Molokai, still has large adult populations in dry lands of the islands, but unfortunately no regeneration from seed has been reported in those areas for many years. The two endemic species were examined using the molecular technique of random amplified polymorphic DNA (RAPD and inter simple sequence repeats (ISSR to determine the genetic structure of the populations and the amount of variation. Both species possess similar genetic structure. Larger and smaller populations of both species contain similar levels of genetic diversity as determined by the number of polymorphic loci, estimated heterozygosity, and Shannon’s index of genetic diversity. Although population diversity of Chrysodracon hawaiiensis (C. hawaiiensis is thought to have remained near pre-disturbance levels, population size continues to decline as recruitment is either absent or does not keep pace with senescence of mature plants. Conservation recommendations for both species are suggested.

  15. Manipulation with heterogeneity within a species population formulated as an inverse problem

    Science.gov (United States)

    Horváth, D.; Brutovsky, B.; Kočišová, J.; Šprinc, S.

    2010-11-01

    Dependence of the evolutionary dynamics on the population’s heterogeneity has been reliably recognized and studied within the frame of evolutionary optimization theory. As the causal relation between the heterogeneity and dynamics of environment has been revealed, the possibility to influence convergence rate of evolutionary processes by purposeful manipulation with environment emerges. For the above purposes we formulate the task as the inverse problem meaning that desired population heterogeneity, quantified by Tsallis information entropy, represents the model’s input and dynamics of environment leading to desired population heterogeneity is looked for. Here the presented abstract model of evolutionary motion within the inverse model of replicating species is case-independent and it is relevant for the broad range of phenomena observed at cellular, ecological, economic and social scales. We envision relevance of the model for anticancer therapy, in which the effort is to circumvent heterogeneity as it typically correlates with the therapy efficiency.

  16. Lack of association between thyroid autoantibodies and parity in a population study argues against microchimerism as a trigger of thyroid autoimmunity

    DEFF Research Database (Denmark)

    Pedersen, Inge Bülow; Laurberg, Peter; Knudsen, Nils

    2006-01-01

    Background: Thyroid autoimmunity is more common in females than in males. One possible explanation for this female preponderance may be the effect of oestrogens on the immune system. It has also been suggested that foetal microchimerism involving transfer of foetal cells into maternal tissue during...... pregnancy may play an important role. Objective: We investigated the association between the presence of circulating thyroid autoantibodies and previous pregnancy. parity and the use of oral contraceptives (OCs) and hormone replacement therapy (HRT) in a population cohort. Methods: We examined 3 712 women...

  17. Lack of association between the tagging SNP A+930-->G of SOCS3 and type 2 diabetes mellitus: meta-analysis of four independent study populations.

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    Antje Fischer-Rosinsky

    Full Text Available BACKGROUND: The suppressor of cytokine signalling 3 (SOCS3 provides a link between cytokine action and their negative consequences on insulin signalling. Thus SOCS3 is a potential candidate gene for type 2 diabetes (T2DM. METHODOLOGY/PRINCIPAL FINDINGS: Based on HapMap we identified the polymorphism A+930-->G (rs4969168 as a haplotype tagging SNP (htSNP sufficiently covering the genetic variation of the whole gene. We therefore examined the association between rs4969168 within SOCS3 and T2DM in three independent study populations; one prospective case-cohort study and two cross-sectional study populations. Due to the low frequency of individuals being homozygous for the polymorphism a dominant model of inheritance was assumed. The case-cohort study with 2,957 individuals (764 of them with incident T2DM showed no effect of the polymorphism on diabetes risk (hazard ratio (95%CI: 0.86 (0.66-1.13; p = 0.3. Within the MeSyBePo-study population 325 subjects had T2DM from a total of 1,897 individuals, while the second cross-sectional cohort included 851 cases of T2DM within a total of 1653 subjects. According to the results in the prospective study, no association with T2DM was found (odds ratio (95%CI: 0.78 (0.54-1.12 for MesyBepo and 1.13 (0.90-1.42 for the Leipzig study population. There was also no association with metabolic subtraits such as insulin sensitivity (p = 0.7, insulin secretion (p = 0.8 or the hyperbolic relation of both, the disposition index (p = 0.7. In addition, no evidence for interaction with BMI or sex was found. We subsequently performed a meta-analysis, additionally including the publicly available data from the T2DM-subcohort of the WTCCC (n = 4,855. The overall odds ratio within that meta-analysis was 0.96 (0.88-1.06. CONCLUSIONS/SIGNIFICANCE: There is no strong effect of the common genetic variation within the SOCS3 gene on the development of T2DM.

  18. The influence of climatic niche preferences on the population genetic structure of a mistletoe species complex.

    Science.gov (United States)

    Ramírez-Barahona, Santiago; González, Clementina; González-Rodríguez, Antonio; Ornelas, Juan Francisco

    2017-06-01

    The prevalent view on genetic structuring in parasitic plants is that host-race formation is caused by varying degrees of host specificity. However, the relative importance of ecological niche divergence and host specificity to population differentiation remains poorly understood. We evaluated the factors associated with population differentiation in mistletoes of the Psittacanthus schiedeanus complex (Loranthaceae) in Mexico. We used genetic data from chloroplast sequences and nuclear microsatellites to study population genetic structure and tested its association with host preferences and climatic niche variables. Pairwise genetic differentiation was associated with environmental and host preferences, independent of geography. However, environmental predictors appeared to be more important than host preferences to explain genetic structure, supporting the hypothesis that the occurrence of the parasite is largely determined by its own climatic niche and, to a lesser degree, by host specificity. Genetic structure is significant within this mistletoe species complex, but the processes associated with this structure appear to be more complex than previously thought. Although host specificity was not supported as the major determinant of population differentiation, we consider this to be part of a more comprehensive ecological model of mistletoe host-race formation that incorporates the effects of climatic niche evolution. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  19. Evidence of ecotypic differentiation between populations of the tree species Parapiptadenia rigida due to flooding.

    Science.gov (United States)

    Silva, D C G; Carvalho, M C C G; Ruas, P M; Ruas, C F; Medri, M E

    2010-05-04

    The tree species Parapiptadenia rigida, native to southern South America, is frequently used in reforestation of riverbanks in Brazil. This tree is also a source of gums, tannins and essential oils, and it has some medicinal uses. We investigated flooding tolerance and genetic diversity in two populations of P. rigida; one of them was naturally exposed to flooding. Plants derived from seeds collected from each population were submitted to variable periods of experimental waterlogging and submergence. Waterlogging promoted a decrease in biomass and structural adjustments, such as superficial roots with aerenchyma and hypertrophied lenticels, that contribute to increase atmospheric oxygen intake. Plants that were submerged had an even greater reduction in biomass and a high mortality rate (40%). The two populations varied significantly in their RAPD marker profiles, in their ability to produce aerenchyma when waterlogged and to survive when submerged, suggesting ecotypic differentiation between them. Hence, the seasonal flooding that has been challenging the tropical riparian forest appears to be genetically modifying the P. rigida populations exposed to it by selecting individuals with increased ability to live under this condition.

  20. Spontaneous morphogenetic juvenilization observed in laboratory populations of vector species of Chagas disease (Triatominae

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    Alina Perlowagora-Szumlewicz

    1973-08-01

    Full Text Available Reported are observations on spontaneous occurring morphogenetic juvenilization in laboratory populations of vector species of Chagas disease. Two general effects have been observed: arrested development and uncoordinated development. These are manifested by supernumerary nymphs (6th stage, intermediate nymphal-adult stages, badly deformed adults developed from 5th instar nymphs, uncoordinated development manifested by grotesque forms of adults, supernumerary adults unable to complete metamorphosis and complete supernumerary adults produced by 6th stage nymphs. The reoccurrence of insects with identical grades of juvenilization in the population is an indication that this is a genetic trait that might be inherited. The factors responsible for morphogenetic juvenilization cannot be transmitted through the juvenilized insects because they are sterile, than they were transmitted through normal insects probably as a recessive or a group recessive factors. The spontaneous morphogenetic juvenilization observed in laboratory populations has a striking similarity to juvenilizing effects induced by application of juvenile hormone analogues, described in the literature and also obtained in our laboratory in a study to be published. Thus it is suggested that both; the altered phenotypes occurring in wild populations and their "phenocopies" induced by the application of juvenile hormone analogues are products of gene controlled identical reactions.

  1. Population dynamics of three songbird species in a nestbox population in Central Europe show effects of density, climate and competitive interactions

    NARCIS (Netherlands)

    Smallegange, I.M.; van der Meer, J.; Fiedler, W.

    2011-01-01

    Unravelling the contributions of density-dependent and density-independent factors in determining species population dynamics is a challenge, especially if the two factors interact. One approach is to apply stochastic population models to long-term data, yet few studies have included interactions

  2. Species delimitation with gene flow: A methodological comparison and population genomics approach to elucidate cryptic species boundaries in Malaysian Torrent Frogs.

    Science.gov (United States)

    Chan, Kin Onn; Alexander, Alana M; Grismer, L Lee; Su, Yong-Chao; Grismer, Jesse L; Quah, Evan S H; Brown, Rafe M

    2017-10-01

    Accurately delimiting species boundaries is a nontrivial undertaking that can have significant effects on downstream inferences. We compared the efficacy of commonly used species delimitation methods (SDMs) and a population genomics approach based on genomewide single-nucleotide polymorphisms (SNPs) to assess lineage separation in the Malaysian Torrent Frog Complex currently recognized as a single species (Amolops larutensis). First, we used morphological, mitochondrial DNA and genomewide SNPs to identify putative species boundaries by implementing noncoalescent and coalescent-based SDMs (mPTP, iBPP, BFD*). We then tested the validity of putative boundaries by estimating spatiotemporal gene flow (fastsimcoal2, ABBA-BABA) to assess the extent of genetic isolation among putative species. Our results show that the A. larutensis complex runs the gamut of the speciation continuum from highly divergent, genetically isolated lineages (mean F st  = 0.9) to differentiating populations involving recent gene flow (mean F st  = 0.05; N m  > 5). As expected, SDMs were effective at delimiting divergent lineages in the absence of gene flow but overestimated species in the presence of marked population structure and gene flow. However, using a population genomics approach and the concept of species as separately evolving metapopulation lineages as the only necessary property of a species, we were able to objectively elucidate cryptic species boundaries in the presence of past and present gene flow. This study does not discount the utility of SDMs but highlights the danger of violating model assumptions and the importance of carefully considering methods that appropriately fit the diversification history of a particular system. © 2017 John Wiley & Sons Ltd.

  3. Contrasting patterns of population structure and demographic history in cryptic species of Bostrychia intricata (Rhodomelaceae, Rhodophyta) from New Zealand.

    Science.gov (United States)

    Muangmai, Narongrit; Fraser, Ceridwen I; Zuccarello, Giuseppe C

    2015-06-01

    Spatial patterns of genetic diversity provide insight into the demography and history of species. Morphologically similar but genetically distinct "cryptic" species are increasingly being recognized in marine organisms through molecular analyses. Such species are, on closer inspection, often discovered to display contrasting life histories or occasionally minor morphological differences; molecular tools can thus be useful indicators of diversity. Bostrychia intricata, a marine red alga, is widely distributed throughout the Southern Hemisphere and comprises many cryptic species. We used mitochondrial cytochrome c oxidase I gene sequences to assess the genetic variation, population genetic structure, and demographic history of B. intricata in New Zealand. Our results supported the existence of three cryptic species of B. intricata (N2, N4, and N5) in New Zealand. Cryptic species N4, which was found throughout New Zealand, showed a higher genetic diversity and wider distribution than the other two species, which were only found in the North Island and northern South Island. Our analyses showed low to moderate genetic differentiation among eastern North Island populations for cryptic species N2, but high differentiation among North and South Island populations for N4, suggesting different population structure between these cryptic species. Data also indicated that N2 has recently undergone population expansion, probably since the Last Glacial Maximum (LGM), while the higher genetic diversity in N4 populations suggests persistence in situ through the LGM. The contrasting population structures and inferred demographic histories of these species highlight that life history can vary greatly even among morphologically indistinguishable taxa. © 2015 Phycological Society of America.

  4. Considering transient population dynamics in the conservation of slow life-history species: An application to the sandhill crane

    Science.gov (United States)

    Gerber, Brian D.; Kendall, William L.

    2016-01-01

    The importance of transient dynamics of structured populations is increasingly recognized in ecology, yet these implications are not largely considered in conservation practices. We investigate transient and long-term population dynamics to demonstrate the process and utility of incorporating transient dynamics into conservation research and to better understand the population management of slow life-history species; these species can be theoretically highly sensitive to short- and long-term transient effects. We are specifically interested in the effects of anthropogenic removal of individuals from populations, such as caused by harvest, poaching, translocation, or incidental take. We use the sandhill crane (Grus canadensis) as an exemplar species; it is long-lived, has low reproduction, late maturity, and multiple populations are subject to sport harvest. We found sandhill cranes to have extremely high potential, but low likelihood for transient dynamics, even when the population is being harvested. The typically low population growth rate of slow life-history species appears to buffer against many perturbations causing large transient effects. Transient dynamics will dominate population trajectories of these species when stage structures are highly biased towards the younger and non-reproducing individuals, a situation that may be rare in established populations of long-lived animals. However, short-term transient population growth can be highly sensitive to vital rates that are relatively insensitive under equilibrium, suggesting that stage structure should be known if perturbation analysis is used to identify effective conservation strategies. For populations of slow life-history species that are not prone to large perturbations to their most productive individuals, population growth may be approximated by equilibrium dynamics.

  5. Population Trends of Central European Montane Birds Provide Evidence for Adverse Impacts of Climate Change on High-Altitude Species.

    Directory of Open Access Journals (Sweden)

    Jiří Flousek

    Full Text Available Climate change is among the most important global threats to biodiversity and mountain areas are supposed to be under especially high pressure. Although recent modelling studies suggest considerable future range contractions of montane species accompanied with increased extinction risk, data allowing to test actual population consequences of the observed climate changes and identifying traits associated to their adverse impacts are very scarce. To fill this knowledge gap, we estimated long-term population trends of montane birds from 1984 to 2011 in a central European mountain range, the Giant Mountains (Krkonoše, where significant warming occurred over this period. We then related the population trends to several species' traits related to the climate change effects. We found that the species breeding in various habitats at higher altitudes had more negative trends than species breeding at lower altitudes. We also found that the species moved upwards as a response to warming climate, and these altitudinal range shifts were associated with more positive population trends at lower altitudes than at higher altitudes. Moreover, long-distance migrants declined more than residents or species migrating for shorter distances. Taken together, these results indicate that the climate change, besides other possible environmental changes, already influences populations of montane birds with particularly adverse impacts on high-altitude species such as water pipit (Anthus spinoletta. It is evident that the alpine species, predicted to undergo serious climatically induced range contractions due to warming climate in the future, already started moving along this trajectory.

  6. Lack of polymorphism at MC1R wild-type allele and evidence of domestic allele introgression across European wild boar populations

    DEFF Research Database (Denmark)

    Canu, Antonio; Vilaça, Sibelle T.; Iacolina, Laura

    2016-01-01

    Domestication promotes the emergence of novel phenotypic and behavioural traits in domesticated animals compared to their wild ancestors. We analysed variation at the melanocortin receptor I (MC1R) and nuclear receptor subfamily 6, group A, member 1 (NR6A1) genes in European wild boar populations......, two loci which have been under strong artificial selection during domestication. These loci influence coat colour and number of vertebrae, respectively. A total of 145 wild boars were sampled throughout Europe, to evaluate frequency and spatial distribution of domestic alleles and patterns...... of hybridization between wild and domestic forms. Most of the wild boars (94%) were homozygous for the European wild-type (E+) MC1R allele. We did not observe any synonymous substitution in the European E+ allele, confirming its monomorphism even in areas known to be hotspots of wild boar genetic diversity...

  7. Filamentous fungal population and species diversity from the continental slope of Bay of Bengal, India

    Science.gov (United States)

    Das, Surajit; Lyla, Parameswari Somasundharan; Khan, Syed Ajmal

    2009-03-01

    Filamentous fungal diversity from the sediments of the continental slope of Bay of Bengal was studied. Sediment samples were collected during two voyages in 2004 and 2005. Filamentous fungal population from both the cruises showed a range of 5.17-59.51 CFU/g and 3.47-29.68 CFU/g, respectively. Totally 16 fungal genera were recorded from both the cruises. Aspergillus was found to be the dominant genus and the overall percentage occurrence was as follows: Deuteromycotina 74%, Ascomycotina 17%, Basidiomycotina 4% and non-sporulating 5%. Diversity indices were calculated and during both the cruises species richness ( d) varied from 0.912 to 3.622 and 1.443 to 4.588; evenness ( J') varied from 0.9183 to 1.000 and 0.8322 to 1.000 and Shannon-Wiener index ( H' log 2) varied from 0.9183 to 1.000 and 1.000 to 3.690. The higher diversity was found in Divipoint transect (northern Bay of Bengal). 95% confidence interval and ellipse showed that the stations were well lying within the funnel. Cluster analysis and MDS grouped the northern transects which showed higher diversity. BVSTEP resulted in isolation of 23 species which were most influential in the marine filamentous fungal diversity of the continental slope of Bay of Bengal. Thus, a lower population range and higher diversity of marine filamentous marine fungi in the sediments of the continental slope of Bay of Bengal was recorded.

  8. Comparative Analysis of the Pattern of Population Genetic Diversity in Three Indo-West Pacific Rhizophora Mangrove Species

    Directory of Open Access Journals (Sweden)

    Yu-Bin Yan

    2016-09-01

    Full Text Available Rhizophora species are the most widely distributed mangrove trees in the Indo-West Pacific (IWP region. Comparative studies of these species with shared life history traits can help identify evolutionary factors that have played most important roles in determining genetic diversity within and between populations in ocean-current dispersed mangrove tree species. We sampled 935 individuals from 54 natural populations for genotyping with 13 microsatellite markers to investigate the level of genetic variation, population structure, and gene flow on a broad geographic scale in Rhizophora apiculata, R. mucronata, and R. stylosa across the IWP region. In contrast to the pattern expected of long-lived woody plants with predominant wind-pollination, water-dispersed seeds and wide geographic range, genetic variation within populations was generally low in all the three species, especially in those peripheral populations from geographic range limits. Although the large water-buoyant propagules of Rhizophora have capacity for long distance dispersal, such events might be rare in reality, as reflected by the low level of gene flow and high genetic differentiation between most of population pairs within each species. Phylogeographic separation of Australian and Pacific island populations from SE Asian lineages previously revealed with DNA sequence data was still detectable in R. apiculata based on genetic distances, but this pattern of disjunction was not always evident in R. mucronata and R. stylosa, suggesting that fast-evolving molecular markers could be more suitable for detecting contemporary genetic structure but not deep evolutionary divergence caused by historical vicariance. Given that mangrove species generally have small effective population sizes, we conclude that genetic drift coupled with limited gene flow have played a dominant role in producing the current pattern of population genetic diversity in the IWP Rhizophora species, overshadowing the

  9. Avian malaria in Hawaiian forest birds: Infection and population impacts across species and elevations

    Science.gov (United States)

    Samuel, Michael D.; Woodworth, Bethany L.; Atkinson, Carter T.; Hart, P. J.; LaPointe, Dennis

    2015-01-01

    Wildlife diseases can present significant threats to ecological systems and biological diversity, as well as domestic animal and human health. However, determining the dynamics of wildlife diseases and understanding the impact on host populations is a significant challenge. In Hawai‘i, there is ample circumstantial evidence that introduced avian malaria (Plasmodium relictum) has played an important role in the decline and extinction of many native forest birds. However, few studies have attempted to estimate disease transmission and mortality, survival, and individual species impacts in this distinctive ecosystem. We combined multi-state capture-recapture (longitudinal) models with cumulative age-prevalence (cross-sectional) models to evaluate these patterns in Apapane, Hawai‘i Amakihi, and Iiwi in low-, mid-, and high-elevation forests on the island of Hawai‘i based on four longitudinal studies of 3–7 years in length. We found species-specific patterns of malaria prevalence, transmission, and mortality rates that varied among elevations, likely in response to ecological factors that drive mosquito abundance. Malaria infection was highest at low elevations, moderate at mid elevations, and limited in high-elevation forests. Infection rates were highest for Iiwi and Apapane, likely contributing to the absence of these species in low-elevation forests. Adult malaria fatality rates were highest for Iiwi, intermediate for Amakihi at mid and high elevations, and lower for Apapane; low-elevation Amakihi had the lowest malaria fatality, providing strong evidence of malaria tolerance in this low-elevation population. Our study indicates that hatch-year birds may have greater malaria infection and/or fatality rates than adults. Our study also found that mosquitoes prefer feeding on Amakihi rather than Apapane, but Apapane are likely a more important reservoir for malaria transmission to mosquitoes. Our approach, based on host abundance and infection rates, may be an

  10. Species interactions and chemical stress combined effects of intraspecific and interspecific interactions and pyrene n Daphnia magna populations dynamics

    NARCIS (Netherlands)

    Viaene, K.P.J.; Laender, de F.; Rico, A.; Brink, van den P.J.; Guardo, Di A.; Morselli, M.; Janssen, C.R.

    2015-01-01

    Species interactions are often suggested as an important factor when assessing the effects of chemicals on higher levels of biological organization. Nevertheless, the contribution of intraspecific and interspecific interactions to chemical effects on populations is often overlooked. In the present

  11. Phylogeography of two parthenogenetic sawfly species (Hymenoptera: Tenthredinidae): relationship of population genetic differentiation to host plant distribution

    NARCIS (Netherlands)

    Müller, C.; Barker, A.; Boevé, J.L.; Jong, de P.W.; Vos, de H.; Brakefield, P.M.

    2004-01-01

    This study compares the population genetic structure of two obligate parthenogenetic sawfly species, Aneugmenus padi (L.) Zhelochovtsev and Eurhadinoceraea ventralis (Panzer) Enslin (Hymenoptera: Tenthredinidae). Allozymes were used to detect genetic differences in larvae collected at different

  12. Lack of association between the fatty acid binding protein 2 (FABP2) polymorphism with obesity and insulin resistance in two aboriginal populations from Chile.

    Science.gov (United States)

    Pérez-Bravo, F; Fuentes, M; Angel, B; Sanchez, H; Carrasco, E; Santos, J L; Lera, L; Albala, C

    2006-12-01

    The aim of this study was to assess the frequency of fatty acid binding protein 2 (FABP2) Ala54Thr genetic polymorphism and to evaluate its association with obesity and insulin resistance in Chilean aboriginal populations. A sample of 96 urban Aymara and 111 urban Mapuche subjects aged 20-80 years were recruited for this cross-sectional study. Glucose, insulin and lipid profile were measured in fasting plasma samples. Insulin resistance was estimated through the HOMA-IR model. FABP2 Ala54Thr genotypes were determined by PCR followed by RFLP analysis. The allele frequency of Thr54 variant was estimated as 18.2% in Aymara subjects, which is one of the lowest reported to date. The corresponding frequency in Mapuche subjects was 31.9% (pMapuche group: OR=2.37, 95% CI 1.319-4.277, p=0.004) It is unlikely that Ala54Thr polymorphism of the FABP2 gene plays a relevant role in obesity and insulin resistance in Chilean ethnic groups.

  13. Variation in Population Synchrony in a Multi-Species Seabird Community: Response to Changes in Predator Abundance.

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    Gail S Robertson

    Full Text Available Ecologically similar sympatric species, subject to typical environmental conditions, may be expected to exhibit synchronous temporal fluctuations in demographic parameters, while populations of dissimilar species might be expected to show less synchrony. Previous studies have tested for synchrony in different populations of single species, and those including data from more than one species have compared fluctuations in only one demographic parameter. We tested for synchrony in inter-annual changes in breeding population abundance and productivity among four tern species on Coquet Island, northeast England. We also examined how manipulation of one independent environmental variable (predator abundance influenced temporal changes in ecologically similar and dissimilar tern species. Changes in breeding abundance and productivity of ecologically similar species (Arctic Sterna paradisaea, Common S. hirundo and Roseate Terns S. dougallii were synchronous with one another over time, but not with a species with different foraging and breeding behaviour (Sandwich Terns Thalasseus sandvicensis. With respect to changes in predator abundance, there was no clear pattern. Roseate Tern abundance was negatively correlated with that of large gulls breeding on the island from 1975 to 2013, while Common Tern abundance was positively correlated with number of large gulls, and no significant correlations were found between large gull and Arctic and Sandwich Tern populations. Large gull abundance was negatively correlated with productivity of Arctic and Common Terns two years later, possibly due to predation risk after fledging, while no correlation with Roseate Tern productivity was found. The varying effect of predator abundance is most likely due to specific differences in the behaviour and ecology of even these closely-related species. Examining synchrony in multi-species assemblages improves our understanding of how whole communities react to long-term changes

  14. Population-based genetic epidemiologic analysis of Chlamydia trachomatis serotypes and lack of association between ompA polymorphisms and clinical phenotypes.

    Science.gov (United States)

    Millman, Kim; Black, Carolyn M; Stamm, Walter E; Jones, Robert B; Hook, Edward W; Martin, David H; Bolan, Gail; Tavaré, Simon; Dean, Deborah

    2006-03-01

    Chlamydia trachomatis is the leading cause of bacterial sexually transmitted diseases worldwide. Urogenital strains are classified into serotypes and genotypes based on the major outer membrane protein and its gene, ompA, respectively. Studies of the association of serotypes with clinical signs and symptoms have produced conflicting results while no studies have evaluated associations with ompA polymorphisms. We designed a population-based cross-sectional study of 344 men and women with urogenital chlamydial infections (excluding co-pathogen infections) presenting to clinics serving five U.S. cities from 1995 to 1997. Signs, symptoms and sequelae of chlamydial infection (mucopurulent cervicitis, vaginal or urethral discharge; dysuria; lower abdominal pain; abnormal vaginal bleeding; and pelvic inflammatory disease) were analyzed for associations with serotype and ompA polymorphisms. One hundred and fifty-three (44.5%) of 344 patients had symptoms consistent with urogenital chlamydial infection. Gender, reason for visit and city were significant independent predictors of symptom status. Men were 2.2 times more likely than women to report any symptoms (P=0.03) and 2.8 times more likely to report a urethral discharge than women were to report a vaginal discharge in adjusted analyses (P=0.007). Differences in serotype or ompA were not predictive except for an association between serotype F and pelvic inflammatory disease (P=0.046); however, the number of these cases was small. While there was no clinically prognostic value associated with serotype or ompA polymorphism for urogenital chlamydial infections except for serotype F, future studies might utilize multilocus genomic typing to identify chlamydial strains associated with clinical phenotypes.

  15. Lack of association between NLGN3, NLGN4, SHANK2 and SHANK3 gene variants and autism spectrum disorder in a Chinese population.

    Directory of Open Access Journals (Sweden)

    Yanyan Liu

    Full Text Available Autism spectrum disorder (ASD is a neurodevelopmental disorder characterized by deficits in social communication, absence or delay in language development, and stereotyped or repetitive behaviors. Genetic studies show that neurexin-neuroligin (NRXN-NLGN pathway genes contribute susceptibility to ASD, which include cell adhesion molecules NLGN3, NLGN4 and scaffolding proteins SHANK2 and SHANK3. Neuroligin proteins play an important role in synaptic function and trans-synaptic signaling by interacting with presynaptic neurexins. Shank proteins are scaffolding molecules of excitatory synapses, which function as central organizers of the postsynaptic density. Sequence level mutations and structural variations in these genes have been identified in ASD cases, while few studies were performed in Chinese population. In this study, we examined the copy numbers of four genes NLGN4, NLGN3, SHANK2, and SHANK3 in 285 ASD cases using multiplex fluorescence competitive polymerase chain reaction (PCR. We also screened the regulatory region including the promoter region and 5'/3' untranslated regions (UTR and the entire coding region of NLGN4 in a cohort of 285 ASD patients and 384 controls by direct sequencing of genomic DNA using the Sanger method. DNA copy number calculation in four genes showed no deletion or duplication in our cases. No missense mutations in NLGN4 were identified in our cohort. Association analysis of 6 common SNPs in NLGN4 did not find significant difference between ASD cases and controls. These findings showed that these genes may not be major disease genes in Chinese ASD cases.

  16. Temperature alters the relative abundance and population growth rates of species within the Dendroctonus frontalis (Coleoptera: Curculionidae) community.

    Science.gov (United States)

    L. Evans; Richard Hoffstetter; Matthew Ayres; Kier Klepzig

    2011-01-01

    Temperature has strong effects on metabolic processes ofindividuals and demographics of populations, but effects on ecological communities are not well known. Many economically and ecologically important pest species have obligate associations with other organisms; therefore, effects of temperature on these species might be mediated by strong interactions. The southern...

  17. Lack of association of MRI determined subclinical cardiovascular disease with dizziness and vertigo in a cross-sectional population-based study.

    Science.gov (United States)

    Lorbeer, Roberto; Hetterich, Holger; Strobl, Ralf; Schafnitzel, Anina; Patscheider, Hannah; Schindler, Andreas; Müller-Peltzer, Katharina; Sommer, Wieland; Peters, Annette; Meisinger, Christa; Heier, Margit; Rathmann, Wolfgang; Bamberg, Fabian; Grill, Eva

    2017-01-01

    We investigated the association between subclinical cardiovascular diseases assessed by MRI examination and symptoms of dizziness and vertigo in participants of a population-based sample. Data from 400 participants (169 women) aged from 39 to 73 of a cross-sectional MRI sub-study of the "Kooperative Gesundheitsforschung in der Region Augsburg" (KORA) FF4 study from the south of Germany was used. MRI determined subclinical cardiovascular diseases include left and right ventricular structure and function as well as the presence of carotid plaque and carotid wall thickness. Cerebrum diseases include white matter lesions (WML) and cerebral microbleeds (CMB). The main outcomes of dizziness and vertigo were assessed by standardized interview. Logistic regression models were applied and adjusted odds ratios (OR) with 95% confidence intervals (CI) were provided. Lifetime and 12-month prevalence of dizziness and vertigo were 30% (95%CI 26% to 35%) and 21% (95%CI 17% to 26%) respectively in this sample. On multivariable analysis, cardiac and carotid measurements were not associated with dizziness and vertigo excluding orthostatic vertigo (20%, 95CI 16% to 24%). Only in male participants, there was a significant association between WML and the presence of dizziness and vertigo (OR = 2.95, 95%CI 1.08 to 8.07). There was no significant association of CMB with dizziness and vertigo. However, CMB and WML were tending to associate with a higher risk of dizziness and vertigo in the whole sample (CMB: OR = 1.48, 95%CI 0.70; 3.15; WML: OR = 1.71, 95%CI 0.80 to 3.67;), in persons with prediabetes and diabetes (WML: OR = 2.71, 95%CI 0.89 to 8.23) and in men with normal glucose metabolism (CMB: OR = 2.60, 95%CI 0.56 to 12.0; WML: OR = 3.08, 95%CI 0.58 to 16.5). In this sample of participants without manifest cardiovascular diseases, subclinical left and right ventricular function and carotid structure were consistently not associated with dizziness and vertigo. Subclinical cerebrum

  18. Lack of association of MRI determined subclinical cardiovascular disease with dizziness and vertigo in a cross-sectional population-based study.

    Directory of Open Access Journals (Sweden)

    Roberto Lorbeer

    Full Text Available We investigated the association between subclinical cardiovascular diseases assessed by MRI examination and symptoms of dizziness and vertigo in participants of a population-based sample.Data from 400 participants (169 women aged from 39 to 73 of a cross-sectional MRI sub-study of the "Kooperative Gesundheitsforschung in der Region Augsburg" (KORA FF4 study from the south of Germany was used. MRI determined subclinical cardiovascular diseases include left and right ventricular structure and function as well as the presence of carotid plaque and carotid wall thickness. Cerebrum diseases include white matter lesions (WML and cerebral microbleeds (CMB. The main outcomes of dizziness and vertigo were assessed by standardized interview. Logistic regression models were applied and adjusted odds ratios (OR with 95% confidence intervals (CI were provided.Lifetime and 12-month prevalence of dizziness and vertigo were 30% (95%CI 26% to 35% and 21% (95%CI 17% to 26% respectively in this sample. On multivariable analysis, cardiac and carotid measurements were not associated with dizziness and vertigo excluding orthostatic vertigo (20%, 95CI 16% to 24%. Only in male participants, there was a significant association between WML and the presence of dizziness and vertigo (OR = 2.95, 95%CI 1.08 to 8.07. There was no significant association of CMB with dizziness and vertigo. However, CMB and WML were tending to associate with a higher risk of dizziness and vertigo in the whole sample (CMB: OR = 1.48, 95%CI 0.70; 3.15; WML: OR = 1.71, 95%CI 0.80 to 3.67;, in persons with prediabetes and diabetes (WML: OR = 2.71, 95%CI 0.89 to 8.23 and in men with normal glucose metabolism (CMB: OR = 2.60, 95%CI 0.56 to 12.0; WML: OR = 3.08, 95%CI 0.58 to 16.5.In this sample of participants without manifest cardiovascular diseases, subclinical left and right ventricular function and carotid structure were consistently not associated with dizziness and vertigo. Subclinical cerebrum

  19. Lack of association of MRI determined subclinical cardiovascular disease with dizziness and vertigo in a cross-sectional population-based study

    Science.gov (United States)

    Hetterich, Holger; Strobl, Ralf; Schafnitzel, Anina; Patscheider, Hannah; Schindler, Andreas; Müller-Peltzer, Katharina; Sommer, Wieland; Peters, Annette; Meisinger, Christa; Heier, Margit; Rathmann, Wolfgang; Bamberg, Fabian; Grill, Eva

    2017-01-01

    Objective We investigated the association between subclinical cardiovascular diseases assessed by MRI examination and symptoms of dizziness and vertigo in participants of a population-based sample. Methods Data from 400 participants (169 women) aged from 39 to 73 of a cross-sectional MRI sub-study of the “Kooperative Gesundheitsforschung in der Region Augsburg” (KORA) FF4 study from the south of Germany was used. MRI determined subclinical cardiovascular diseases include left and right ventricular structure and function as well as the presence of carotid plaque and carotid wall thickness. Cerebrum diseases include white matter lesions (WML) and cerebral microbleeds (CMB). The main outcomes of dizziness and vertigo were assessed by standardized interview. Logistic regression models were applied and adjusted odds ratios (OR) with 95% confidence intervals (CI) were provided. Results Lifetime and 12-month prevalence of dizziness and vertigo were 30% (95%CI 26% to 35%) and 21% (95%CI 17% to 26%) respectively in this sample. On multivariable analysis, cardiac and carotid measurements were not associated with dizziness and vertigo excluding orthostatic vertigo (20%, 95CI 16% to 24%). Only in male participants, there was a significant association between WML and the presence of dizziness and vertigo (OR = 2.95, 95%CI 1.08 to 8.07). There was no significant association of CMB with dizziness and vertigo. However, CMB and WML were tending to associate with a higher risk of dizziness and vertigo in the whole sample (CMB: OR = 1.48, 95%CI 0.70; 3.15; WML: OR = 1.71, 95%CI 0.80 to 3.67;), in persons with prediabetes and diabetes (WML: OR = 2.71, 95%CI 0.89 to 8.23) and in men with normal glucose metabolism (CMB: OR = 2.60, 95%CI 0.56 to 12.0; WML: OR = 3.08, 95%CI 0.58 to 16.5). Conclusions In this sample of participants without manifest cardiovascular diseases, subclinical left and right ventricular function and carotid structure were consistently not associated with

  20. Misunderstood or lacking legitimacy?

    OpenAIRE

    Cohen, G; Sims, D

    2007-01-01

    In spite of the rising interest in marketing within professional service firms in the last twenty years, past research has identified a reluctant acceptance and application of marketing within these organisations. The present paper will debate whether this is due to lack of understanding of the role of marketing, lack of acceptance as a valid management discipline suitable for professional services or lack of legitimacy as a profession in its own right. A brief overview of the role of marketi...

  1. Species distribution and population connectivity of deep-sea mussels at hydrocarbon seeps in the Gulf of Mexico.

    Directory of Open Access Journals (Sweden)

    Baptiste Faure

    Full Text Available Hydrocarbon seepage is widespread and patchy in the Gulf of Mexico, and six species of symbiont containing bathymodiolin mussels are found on active seeps over wide and overlapping depth and geographic ranges. We use mitochondrial genes to discriminate among the previously known and a newly discovered species and to assess the connectivity among populations of the same species in the northern Gulf of Mexico (GoM. Our results generally validate the morphologically based distribution of the three previously known GoM species of Bathymodiolus, although we found that approximately 10% of the morphologically based identifications were incorrect and this resulted in some inaccuracies with respect to their previously assigned depth and geographical distribution patterns. These data allowed us to confirm that sympatry of two species of Bathymodiolus within a single patch of mussels is common. A new species of bathymodiolin, Bathymodiolus sp. nov., closely related to B. heckerae was also discovered. The two species live at the same depths but have not been found in sympatry and both have small effective population sizes. We found evidence for genetic structure within populations of the three species of Bathymodiolinae for which we had samples from multiple sites and suggest limited connectivity for populations at some sites. Despite relatively small sample sizes, genetic diversity indices suggest the largest population sizes for B. childressi and Tamu fisheri and the smallest for B. heckerae and B. sp. nov. among the GoM bathymodiolins. Moreover, we detected an excess of rare variants indicating recent demographic changes and population expansions for the four species of bathymodiolins from the Gulf of Mexico.

  2. Discrete time population dynamics of a two-stage species with recruitment and capture

    International Nuclear Information System (INIS)

    Ladino, Lilia M.; Mammana, Cristiana; Michetti, Elisabetta; Valverde, Jose C.

    2016-01-01

    This work models and analyzes the dynamics of a two-stage species with recruitment and capture factors. It arises from the discretization of a previous model developed by Ladino and Valverde (2013), which represents a progress in the knowledge of the dynamics of exploited populations. Although the methods used here are related to the study of discrete-time systems and are different from those related to continuous version, the results are similar in both the discrete and the continuous case what confirm the skill in the selection of the factors to design the model. Unlike for the continuous-time case, for the discrete-time one some (non-negative) parametric constraints are derived from the biological significance of the model and become fundamental for the proofs of such results. Finally, numerical simulations show different scenarios of dynamics related to the analytical results which confirm the validity of the model.

  3. Series solution for continuous population models for single and interacting species by the homotopy analysis method

    Directory of Open Access Journals (Sweden)

    Magdy A. El-Tawil

    2012-07-01

    Full Text Available The homotopy analysis method (HAM is used to find approximate analytical solutions of continuous population models for single and interacting species. The homotopy analysis method contains the auxiliary parameter $hbar,$ which provides us with a simple way to adjust and control the convergence region of series solution. the solutions are compared with the numerical results obtained using NDSolve, an ordinary differential equation solver found in the Mathematica package and a good agreement is found. Also the solutions are compared with the available analytic results obtained by other methods and more accurate and convergent series solution found. The convergence region is also computed which shows the validity of the HAM solution. This method is reliable and manageable.

  4. River Networks As Ecological Corridors for Species, Populations and Pathogens of Water-Borne Disease

    Science.gov (United States)

    Rinaldo, A.

    2014-12-01

    River basins are a natural laboratory for the study of the integration of hydrological, ecological and geomorphological processes. Moving from morphological and functional analyses of dendritic geometries observed in Nature over a wide range of scales, this Lecture addresses essential ecological processes that take place along dendritic structures, hydrology-driven and controlled, like e.g.: population migrations and human settlements, that historically proceeded along river networks to follow water supply routes; riparian ecosystems composition that owing to their positioning along streams play crucial roles in their watersheds and in the loss of biodiversity proceeding at unprecedented rates; waterborne disease spreading, like epidemic cholera that exhibits epidemic patterns that mirror those of watercourses and of human mobility and resurgences upon heavy rainfall. Moreover, the regional incidence of Schistosomiasis, a parasitic waterborne disease, and water resources developments prove tightly related, and proliferative kidney disease in fish thrives differently in pristine and engineered watercourses: can we establish quantitatively the critical linkages with hydrologic drivers and controls? How does connectivity within a river network affect community composition or the spreading mechanisms? Does the river basin act as a template for biodiversity or for species' persistence? Are there hydrologic controls on epidemics of water-borne disease? Here, I shall focus on the noteworthy scientific perspectives provided by spatially explicit eco-hydrological studies centered on river networks viewed as ecological corridors for species, populations and pathogens of waterborne disease. A notable methodological coherence is granted by the mathematical description of river networks as the support for reactive transport. The Lecture overviews a number of topics idiosyncratically related to my own research work but ideally aimed at a coherent body of materials and methods. A

  5. The danger within: the role of genetic, behavioural and ecological factors in population persistence of colour polymorphic species.

    Science.gov (United States)

    Bolton, Peri E; Rollins, Lee A; Griffith, Simon C

    2015-06-01

    Polymorphic species have been the focus of important work in evolutionary biology. It has been suggested that colour polymorphic species have specific evolutionary and population dynamics that enable them to persist through environmental changes better than less variable species. We suggest that recent empirical and theoretical work indicates that polymorphic species may be more vulnerable to extinction than previously thought. This vulnerability arises because these species often have a number of correlated sexual, behavioural, life history and ecological traits, which can have a simple genetic underpinning. When exacerbated by environmental change, these alternate strategies can lead to conflict between morphs at the genomic and population levels, which can directly or indirectly affect population and evolutionary dynamics. In this perspective, we identify a number of ways in which the nature of the correlated traits, their underpinning genetic architecture, and the inevitable interactions between colour morphs can result in a reduction in population fitness. The principles illustrated here apply to all kinds of discrete polymorphism (e.g. behavioural syndromes), but we focus primarily on colour polymorphism because they are well studied. We urge further empirical investigation of the genetic architecture and interactions in polymorphic species to elucidate the impact on population fitness. © 2015 John Wiley & Sons Ltd.

  6. A method to assess the population-level consequences of wind energy facilities on bird and bat species: Chapter

    Science.gov (United States)

    Diffendorfer, James E.; Beston, Julie A.; Merrill, Matthew; Stanton, Jessica C.; Corum, Margo D.; Loss, Scott R.; Thogmartin, Wayne E.; Johnson, Douglas H.; Erickson, Richard A.; Heist, Kevin W.

    2016-01-01

    For this study, a methodology was developed for assessing impacts of wind energy generation on populations of birds and bats at regional to national scales. The approach combines existing methods in applied ecology for prioritizing species in terms of their potential risk from wind energy facilities and estimating impacts of fatalities on population status and trend caused by collisions with wind energy infrastructure. Methods include a qualitative prioritization approach, demographic models, and potential biological removal. The approach can be used to prioritize species in need of more thorough study as well as to identify species with minimal risk. However, the components of this methodology require simplifying assumptions and the data required may be unavailable or of poor quality for some species. These issues should be carefully considered before using the methodology. The approach will increase in value as more data become available and will broaden the understanding of anthropogenic sources of mortality on bird and bat populations.

  7. Population Genomics Reveals Speciation and Introgression between Brown Norway Rats and Their Sibling Species.

    Science.gov (United States)

    Teng, Huajing; Zhang, Yaohua; Shi, Chengmin; Mao, Fengbiao; Cai, Wanshi; Lu, Liang; Zhao, Fangqing; Sun, Zhongsheng; Zhang, Jianxu

    2017-09-01

    Murine rodents are excellent models for study of adaptive radiations and speciation. Brown Norway rats (Rattus norvegicus) are successful global colonizers and the contributions of their domesticated laboratory strains to biomedical research are well established. To identify nucleotide-based speciation timing of the rat and genomic information contributing to its colonization capabilities, we analyzed 51 whole-genome sequences of wild-derived Brown Norway rats and their sibling species, R. nitidus, and identified over 20 million genetic variants in the wild Brown Norway rats that were absent in the laboratory strains, which substantially expand the reservoir of rat genetic diversity. We showed that divergence of the rat and its siblings coincided with drastic climatic changes that occurred during the Middle Pleistocene. Further, we revealed that there was a geographically widespread influx of genes between Brown Norway rats and the sibling species following the divergence, resulting in numerous introgressed regions in the genomes of admixed Brown Norway rats. Intriguing, genes related to chemical communications among these introgressed regions appeared to contribute to the population-specific adaptations of the admixed Brown Norway rats. Our data reveals evolutionary history of the Brown Norway rat, and offers new insights into the role of climatic changes in speciation of animals and the effect of interspecies introgression on animal adaptation. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  8. Differential impacts of wildfire on the population dynamics of an old-forest species.

    Science.gov (United States)

    Rockweit, Jeremy T; Franklin, Alan B; Carlson, Peter C

    2017-06-01

    Ecological disturbances shape and maintain natural communities, but climate change and human land use can alter disturbance regimes and affect population persistence and vital rates in unpredictable ways. Species inhabiting landscapes shaped by wildfire have evolved mechanisms allowing them to persist under this dynamic disturbance type, which creates habitats of varying quality for these species. We utilized data from a 26-yr demographic study of northern spotted owls to analyze the influence of wildfire on apparent survival and recruitment rates. Wildfires occurred across different years and affected different spotted owl territories, which allowed us to implement a retrospective Before-After-Control-Impact (BACI) analysis and model the potential effect of wildfire extent and severity. Our results indicated that mixed-severity fires that burned at predominantly low-severity had little effect on survival and recruitment while fires characterized by more medium to high burn severities negatively affected spotted owl survival, with varying effects on recruitment. Reduced survival and increased recruitment rates on some territories affected by medium to high severity fires suggested that post-fire habitat quality was reduced resulting in territories that were marginally capable of supporting owls. We hypothesize these territories may have represented "sinks" that were supported by nearby "source" territories in a spatially heterogeneous landscape created by the mixed-severity fire regime of the region. © 2017 by the Ecological Society of America.

  9. Climate change and the distribution of neotropical red-bellied toads (Melanophryniscus, Anura, Amphibia): how to prioritize species and populations?

    Science.gov (United States)

    Zank, Caroline; Becker, Fernando Gertum; Abadie, Michelle; Baldo, Diego; Maneyro, Raúl; Borges-Martins, Márcio

    2014-01-01

    We used species distribution modeling to investigate the potential effects of climate change on 24 species of Neotropical anurans of the genus Melanophryniscus. These toads are small, have limited mobility, and a high percentage are endangered or present restricted geographical distributions. We looked at the changes in the size of suitable climatic regions and in the numbers of known occurrence sites within the distribution limits of all species. We used the MaxEnt algorithm to project current and future suitable climatic areas (a consensus of IPCC scenarios A2a and B2a for 2020 and 2080) for each species. 40% of the species may lose over 50% of their potential distribution area by 2080, whereas 28% of species may lose less than 10%. Four species had over 40% of the currently known occurrence sites outside the predicted 2080 areas. The effect of climate change (decrease in climatic suitable areas) did not differ according to the present distribution area, major habitat type or phylogenetic group of the studied species. We used the estimated decrease in specific suitable climatic range to set a conservation priority rank for Melanophryniscus species. Four species were set to high conservation priority: M. montevidensis, (100% of its original suitable range and all known occurrence points potentially lost by 2080), M. sp.2, M. cambaraensis, and M. tumifrons. Three species (M. spectabilis, M. stelzneri, and M. sp.3) were set between high to intermediate priority (more than 60% decrease in area predicted by 2080); nine species were ranked as intermediate priority, while eight species were ranked as low conservation priority. We suggest that monitoring and conservation actions should be focused primarily on those species and populations that are likely to lose the largest area of suitable climate and the largest number of known populations in the short-term.

  10. Climate change and the distribution of neotropical red-bellied toads (Melanophryniscus, Anura, Amphibia: how to prioritize species and populations?

    Directory of Open Access Journals (Sweden)

    Caroline Zank

    Full Text Available We used species distribution modeling to investigate the potential effects of climate change on 24 species of Neotropical anurans of the genus Melanophryniscus. These toads are small, have limited mobility, and a high percentage are endangered or present restricted geographical distributions. We looked at the changes in the size of suitable climatic regions and in the numbers of known occurrence sites within the distribution limits of all species. We used the MaxEnt algorithm to project current and future suitable climatic areas (a consensus of IPCC scenarios A2a and B2a for 2020 and 2080 for each species. 40% of the species may lose over 50% of their potential distribution area by 2080, whereas 28% of species may lose less than 10%. Four species had over 40% of the currently known occurrence sites outside the predicted 2080 areas. The effect of climate change (decrease in climatic suitable areas did not differ according to the present distribution area, major habitat type or phylogenetic group of the studied species. We used the estimated decrease in specific suitable climatic range to set a conservation priority rank for Melanophryniscus species. Four species were set to high conservation priority: M. montevidensis, (100% of its original suitable range and all known occurrence points potentially lost by 2080, M. sp.2, M. cambaraensis, and M. tumifrons. Three species (M. spectabilis, M. stelzneri, and M. sp.3 were set between high to intermediate priority (more than 60% decrease in area predicted by 2080; nine species were ranked as intermediate priority, while eight species were ranked as low conservation priority. We suggest that monitoring and conservation actions should be focused primarily on those species and populations that are likely to lose the largest area of suitable climate and the largest number of known populations in the short-term.

  11. The extent of population genetic subdivision differs among four co-distributed shark species in the Indo-Australian archipelago

    Directory of Open Access Journals (Sweden)

    Giles Jenny

    2009-02-01

    Full Text Available Abstract Background The territorial fishing zones of Australia and Indonesia are contiguous to the north of Australia in the Timor and Arafura Seas and in the Indian Ocean to the north of Christmas Island. The area surrounding the shared boundary consists of a variety of bio-diverse marine habitats including shallow continental shelf waters, oceanic trenches and numerous offshore islands. Both countries exploit a variety of fisheries species, including whaler (Carcharhinus spp. and hammerhead sharks (Sphyrna spp.. Despite their differences in social and financial arrangements, the two countries are motivated to develop complementary co-management practices to achieve resource sustainability. An essential starting point is knowledge of the degree of population subdivision, and hence fisheries stock status, in exploited species. Results Populations of four commercially harvested shark species (Carcharhinus obscurus, Carcharhinus sorrah, Prionace glauca, Sphyrna lewini were sampled from northern Australia and central Indonesia. Neutral genetic markers (mitochondrial DNA control region sequence and allelic variation at co-dominant microsatellite loci revealed genetic subdivision between Australian and Indonesian populations of C. sorrah. Further research is needed to address the possibility of genetic subdivision among C. obscurus populations. There was no evidence of genetic subdivision for P. glauca and S. lewini populations, but the sampling represented a relatively small part of their distributional range. For these species, more detailed analyses of population genetic structure is recommended in the future. Conclusion Cooperative management between Australia and Indonesia is the best option at present for P. glauca and S. lewini, while C. sorrah and C. obscurus should be managed independently. On-going research on these and other exploited shark and ray species is strongly recommended. Biological and ecological similarity between species may

  12. River networks as ecological corridors for species, populations and pathogens of water-borne disease (Invited)

    Science.gov (United States)

    Rinaldo, A.; Bertuzzo, E.; Mari, L.; Suweis, S.; Ceola, S.; Carrara, F.; Rodriguez-Iturbe, I.

    2010-12-01

    Recent works at the interface of hydrology, geomorphology and ecology under an integrated framework of analysis will be reviewed with a view to a general theory for reactive transport on networks. A number of related topics will be reviewed, linked by the characters of stochastic transport, and the networked environmental matrix (including biodiversity of freshwater fish in river networks and vegetation along riparian systems, how river networks affected historic spreading of human populations, and how they influence the spreading of water-borne disease). The unique, coherent ecohydrological thread and similar mathematical methods will be exposed. Metacommunity and individual-based models will be described in the contexts of hydrochory, population and species migrations, and the spreading of infections of water-borne disease along the ecological corridors generated by the river basin. A general effect is shown to emerge on the effects of dendritic geometries on the ecological processes and dynamics operating on river basins. Insights provided by such a theory will lend themselves to issues of practical importance such as integration of riparian systems into large-scale resource management, spatial strategies to minimize loss of freshwater biodiversity, and effective prevention/vaccination campaigns against water-borne diseases.

  13. Ultra-deep sequencing of intra-host rabies virus populations during cross-species transmission.

    Science.gov (United States)

    Borucki, Monica K; Chen-Harris, Haiyin; Lao, Victoria; Vanier, Gilda; Wadford, Debra A; Messenger, Sharon; Allen, Jonathan E

    2013-11-01

    One of the hurdles to understanding the role of viral quasispecies in RNA virus cross-species transmission (CST) events is the need to analyze a densely sampled outbreak using deep sequencing in order to measure the amount of mutation occurring on a small time scale. In 2009, the California Department of Public Health reported a dramatic increase (350) in the number of gray foxes infected with a rabies virus variant for which striped skunks serve as a reservoir host in Humboldt County. To better understand the evolution of rabies, deep-sequencing was applied to 40 unpassaged rabies virus samples from the Humboldt outbreak. For each sample, approximately 11 kb of the 12 kb genome was amplified and sequenced using the Illumina platform. Average coverage was 17,448 and this allowed characterization of the rabies virus population present in each sample at unprecedented depths. Phylogenetic analysis of the consensus sequence data demonstrated that samples clustered according to date (1995 vs. 2009) and geographic location (northern vs. southern). A single amino acid change in the G protein distinguished a subset of northern foxes from a haplotype present in both foxes and skunks, suggesting this mutation may have played a role in the observed increased transmission among foxes in this region. Deep-sequencing data indicated that many genetic changes associated with the CST event occurred prior to 2009 since several nonsynonymous mutations that were present in the consensus sequences of skunk and fox rabies samples obtained from 20032010 were present at the sub-consensus level (as rare variants in the viral population) in skunk and fox samples from 1995. These results suggest that analysis of rare variants within a viral population may yield clues to ancestral genomes and identify rare variants that have the potential to be selected for if environment conditions change.

  14. Ultra-deep sequencing of intra-host rabies virus populations during cross-species transmission.

    Directory of Open Access Journals (Sweden)

    Monica K Borucki

    2013-11-01

    Full Text Available One of the hurdles to understanding the role of viral quasispecies in RNA virus cross-species transmission (CST events is the need to analyze a densely sampled outbreak using deep sequencing in order to measure the amount of mutation occurring on a small time scale. In 2009, the California Department of Public Health reported a dramatic increase (350 in the number of gray foxes infected with a rabies virus variant for which striped skunks serve as a reservoir host in Humboldt County. To better understand the evolution of rabies, deep-sequencing was applied to 40 unpassaged rabies virus samples from the Humboldt outbreak. For each sample, approximately 11 kb of the 12 kb genome was amplified and sequenced using the Illumina platform. Average coverage was 17,448 and this allowed characterization of the rabies virus population present in each sample at unprecedented depths. Phylogenetic analysis of the consensus sequence data demonstrated that samples clustered according to date (1995 vs. 2009 and geographic location (northern vs. southern. A single amino acid change in the G protein distinguished a subset of northern foxes from a haplotype present in both foxes and skunks, suggesting this mutation may have played a role in the observed increased transmission among foxes in this region. Deep-sequencing data indicated that many genetic changes associated with the CST event occurred prior to 2009 since several nonsynonymous mutations that were present in the consensus sequences of skunk and fox rabies samples obtained from 20032010 were present at the sub-consensus level (as rare variants in the viral population in skunk and fox samples from 1995. These results suggest that analysis of rare variants within a viral population may yield clues to ancestral genomes and identify rare variants that have the potential to be selected for if environment conditions change.

  15. Allozyme variation in Pinus cembra and P. sibirica: differentiation between populations and species

    Directory of Open Access Journals (Sweden)

    D.V. Politov

    2013-12-01

    Full Text Available Two closely related Eurasian species of 5-needle pines, Swiss stone pine(Pinus cembra L. and Siberian stone pine (P. sibirica Du Tour occupy two disjunctive parts of the formerly common range in Europe andSiberia, respectively. These forms show so close morphological and genetic similarity that in some classifications they are treated as subspecies. Using a set of 29 allozyme loci (Adh-1,-2, Fdh, Fest-2, Gdh, Got-1,-2,-3, Idh, Lap- 2,-3, Mdh-1,-2,-3,-4, Mnr-1, Pepca, 6-Pgd-1,-2,-3, Pgi-1,-2, Pgm-1,-2, Skdh-1,-2, Sod-2,-3,- 4 we analyzed genetic differentiation within the Alpine-Carpathian part of the range (P.cembra and found relatively low genetic diversity for conifers (HE=0,08 and moderate level of differentiation (FST=7,4%. For thesame loci set within Siberian populations (P. sibirica genic diversity was higher (0,14, while differentiation was lower (3%. The factthat differentiation within the highly fragmented range of Swiss stone pine is just 2.5 times higher than in widespread closely related P.sibirica makes us consider factors other than unlimited gene flow responsible for uniformity of allelic frequencies. Among these factors the leading role belongs to balancing selection.Heterozygote superiority leads to both (i increasing of heterozygosity in course of stand development and (ii through balancing selectionto stable equilibrium state. Under this equilibrium, virtually the same genetic structure is maintained, even when remote and isolatedparts of the species' ranges are compared. For many studied loci, Swiss and Siberian stone pines have the same allelic profiles despite the fact that gene flow among them ceased a long time ago. According to one point of view fragmentation of the formerly united range might take place in the Atlantic time of the Holocene (about 5000 years BC, however, an alternative hypothesis refers to a much earlierPleistocene glacial time. Analysis of a combined data set (P. cembra

  16. Population differentiation in mediterranean plants: insights into colonization history and the evolution and conservation of endemic species

    Science.gov (United States)

    Thompson

    1999-04-01

    Colonization and isolation are critical events in the evolutionary dynamics of plant populations. In this paper I review how spatial population structure of genetic markers provides insights into the evolutionary significance of episodes of colonization and isolation in the Mediterranean flora. I use as themes to structure my review the following topics: spatial structure induced by historical associations among populations of widespread species; population differentiation in relation to the evolution of closely related species with disjunct distributions; the potential effect of founder events during colonization on character evolution; and the conservation implications of spatial population structure. My review illustrates that the Mediterranean flora is full of examples that provide key insights into such evolutionary and conservation issues.

  17. The effect of wildfire on population dynamics for two native small mammal species in a coastal heathland in Queensland, Australia

    Science.gov (United States)

    Liedloff, Adam C.; Wilson, John C.; Engeman, Richard M.

    2018-04-01

    The influences of wildfire through population dynamics and life history for two species of small mammals in a south-east Queensland heathland on Bribie Island are presented. Trapping results provided information on breeding, immigration and movement of Melomys burtoni (Grassland melomys) and Rattus lutreolus (Swamp rat). We first investigated and optimized the design of trapping methodology for producing mark-recapture population estimates to compare two adjacent populations, one of which was subjected to an extensive wildfire during the two year study. We consider how well rodents survive wildfire and whether the immediate impacts of fire or altered habitat have the greatest impact on each species. We found the R. lutreolus population was far more influenced by the fire than the M. burtoni population both immediately after the fire and over 18 months of vegetation recovery.

  18. Species interactions and chemical stress: combined effects of intraspecific and interspecific interactions and pyrene on Daphnia magna population dynamics.

    Science.gov (United States)

    Viaene, Karel P J; De Laender, Frederik; Rico, Andreu; Van den Brink, Paul J; Di Guardo, Antonio; Morselli, Melissa; Janssen, Colin R

    2015-08-01

    Species interactions are often suggested as an important factor when assessing the effects of chemicals on higher levels of biological organization. Nevertheless, the contribution of intraspecific and interspecific interactions to chemical effects on populations is often overlooked. In the present study, Daphnia magna populations were initiated with different levels of intraspecific competition, interspecific competition, and predation and exposed to pyrene pulses. Generalized linear models were used to test which of these factors significantly explained population size and structure at different time points. Pyrene had a negative effect on total population densities, with effects being more pronounced on smaller D. magna individuals. Among all species interactions tested, predation had the largest negative effect on population densities. Predation and high initial intraspecific competition were shown to interact antagonistically with pyrene exposure. This was attributed to differences in population structure before pyrene exposure and pyrene-induced reductions in predation pressure by Chaoborus sp. larvae. The present study provides empirical evidence that species interactions within and between populations can alter the response of aquatic populations to chemical exposure. Therefore, such interactions are important factors to be considered in ecological risk assessments. © 2015 SETAC.

  19. Geometric and morphometric analysis of fish scales to identity genera, species and populations case study: the Cyprinid family

    Directory of Open Access Journals (Sweden)

    Seyedeh Narjes Tabatabei

    2014-01-01

    Full Text Available Using fish scale to identity species and population is a rapid, safe and low cost method. Hence, this study was carried out to investigate the possibility of using geometric and morphometric methods in fish scales for rapid identification of species and populations and compare the efficiency of applying few and/or high number of landmark points. For this purpose, scales of one population of Luciobarbus capito, four populations of Alburnoides eichwaldii and two populations of Rutilus frisii kutum, all belonging to cyprinid family, were examined. On two-dimensional images of the scales 7 and 23 landmark points were digitized in two separate times using TpsDig2, respectively. Landmark data after generalized procrustes analysis were analyzed using Principal Component Analysis (PCA, Canonical Variate Analysis (CVA and Cluster Analysis. The results of both methods (using 7 and 23 landmark points showed significant differences of the shape of scales among the three species studied (P0.05. The results also showed that few number of landmarks could display the differences between scale shapes. According to the results of this study, it could be stated that the scale of each species had unique shape patterns which could be utilized as a species identification key.

  20. Genetic Diversity and Population Structure of a Threatened African Tree Species, Milicia excelsa, Using Nuclear Micro satellites DNA Markers

    International Nuclear Information System (INIS)

    Ouinsavi, Ch.; Sokpon, N.; Ouinsavi, Ch.; Khasa, D.P.

    2009-01-01

    To accurately estimate the genetic diversity and population structure for improved conservation planning of Milicia excelsa tree, 212 individuals from twelve population samples covering the species' range in Benin were surveyed at seven specific micro satellite DNA loci. All loci were variable, with the mean number of alleles per locus ranging from 5.86 to 7.69. Considerable genetic variability was detected for all populations at the seven loci (AR=4.60; HE=0.811). Moderate but statistically significant genetic differentiation was found among populations considering both FST (0.112) and RST (0.342). All of the populations showed heterozygosity deficits in test of Hardy-Weinberg Equilibrium and significantly positive FIS values due to inbreeding occurring in the species. Pairwise FST values were positively and significantly correlated with geographical distances (r=0.432; P=.007, Mantel's test) indicating that populations are differentiated by isolation by distance. Bayesian analysis of population structure showed division of the genetic variation into four clusters revealing the existence of heterogeneity in population genetic structure. Altogether, these results indicate that genetic variation in Milicia excelsa is geographically structured. Information gained from this study also emphasized the need for in situ conservation of the relict populations and establishment of gene flow corridors through agroforestry systems for interconnecting these remnant populations.

  1. Operculina from the northwestern Pacific (Sesoko Island, Japan) Species Differentiation, Population Dynamics, Growth and Development

    Science.gov (United States)

    Woeger, Julia; Eder, Wolfgang; Kinoshita, Shunichi; Briguglio, Antonino; Hohenegger, Johann

    2017-04-01

    During the last decades larger benthic foraminifera have gained importance as indicator species and are used in a variety of applications, from ecological monitoring, studying the effects of ocean acidification, or reconstructing paleoenvironments. They significantly contribute to the carbonate budget of costal areas and are invaluable tools in biostratigraphy. Even before their advancement as bioindicators, laboratory experiments have been conducted to investigate the effects of various ecological parameters on community composition, biology of single species, or investigating the effects of salinity and temperature on stable isotope composition of the foraminiferal test, to name only a few. The natural laboratory approach (continuous sampling over a period of more than one year) was conducted at the island of Sesoko (Okinawa, Japan). in combination with µ-CT scanning was used to reveal population dynamics of 3 different morphotypes of Operculina. The clarification of reproductive cycles as well as generation and size abundances were used to calculate natural growth models. Best fit was achieved using Bertalanffy and Michaelis-Menten functions. Exponential-, logistic-, generalized logistic-, Gompertz-function yielded weaker fits, when compared by coefficient of determination as well as Akaike Information criterion. The resulting growth curves and inferred growth rates were in turn used to evaluate the quality of a laboratory cultivation experiment carried out simultaneously over a period of 15 months. Culturing parameters such as temperature, light intensities, salinity and pH and light-dark duration were continuously adapted to measurements in the field. The average investigation time in culture was 77days. 13 Individuals lived more than 200 days, 3 reproduced asexually and one sexually. 14% of 186 Individuals were lost, while 22% could not be kept alive for more than one month. Growth curves also represent an instrumental source of information for the various

  2. Applying surrogate species presences to correct sample bias in species distribution models: a case study using the Pilbara population of the Northern Quoll

    Directory of Open Access Journals (Sweden)

    Shaun W. Molloy

    2017-05-01

    Full Text Available The management of populations of threatened species requires the capacity to identify areas of high habitat value. We developed a high resolution species distribution model (SDM for the endangered Pilbara northern quoll Dasyurus hallucatus, population using MaxEnt software and a combined suite of bioclimatic and landscape variables. Once common throughout much of northern Australia, this marsupial carnivore has recently declined throughout much of its former range and is listed as endangered by the IUCN. Other than the potential threats presented by climate change, and the invasive cane toad Rhinella marina (which has not yet arrived in the Pilbara. The Pilbara population is also impacted by introduced predators, pastoral and mining activities. To account for sample bias resulting from targeted surveys unevenly spread through the region, a pseudo-absence bias layer was developed from presence records of other critical weight-range non-volant mammals. The resulting model was then tested using the biomod2 package which produces ensemble models from individual models created with different algorithms. This ensemble model supported the distribution determined by the bias compensated MaxEnt model with a covariance of of 86% between models with both models largely identifying the same areas as high priority habitat. The primary product of this exercise is a high resolution SDM which corroborates and elaborates on our understanding of the ecology and habitat preferences of the Pilbara Northern Quoll population thereby improving our capacity to manage this population in the face of future threats.

  3. Rapid assessment of populations trends of invasive species: Singular Spectrum Analysis (SSA

    Directory of Open Access Journals (Sweden)

    DANA, ED

    2010-01-01

    Full Text Available Singular Spectrum Analysis (SSA is a powerful analytical approach for biodi-versity management. Its main advan-tages are due to its intuitive processing and visualization, since mathematical workflow is conceptually similar to the widely accepted Principal Components Analysis. Detailed analyses of popula-tion trends with mathematical tools are often difficult to achieve for managers by a number of reasons (large numbers or areas monitored, large number of species, insufficient statistics skills, strong knowledge level in demographic analyses, etc.. SSA has been used since the 1970’s in signal processing to clarify signal vs. noisy information, but it has also been used in climate change analy-sis and other developmental areas. Be-sides, SSA is a rapid-learning method for technicians and managers with medium level of mathematical knowledge. Free software in Unix environment is avail-able. Unfortunately, no free and friendly software is available for Win-dows SO. Although R package may offer solutions for really advanced users, it does not fit real work situations for managers of biological invasions. Cater-pillar (Gistat Group, Ltd is by now, the best option found by the author in terms of price, facility for results inter-pretation and time consumed in learn-ing. The main disadvantage is the poor content of tutorial files

  4. Population dynamics, antibiotics resistance and biofilm formation of Aeromonas and Vibrio species isolated from aquatic sources in Northern Malaysia.

    Science.gov (United States)

    Odeyemi, Olumide A; Ahmad, Asmat

    2017-02-01

    This study aimed to compare population dynamics, antibiotic resistance and biofilm formation of Aeromonas and Vibrio species from seawater and sediment collected from Northern Malaysia. Isolates with different colony morphology were characterized using both biochemical and molecular methods before testing for antibiotic resistance and biofilm formation. Results obtained from this study showed that in Kedah, the population of Aeromonas isolated from sediment was highest in Pantai Merdeka (8.22 log CFU/ml), Pulau Bunting recorded the highest population of Aeromonas from sediment (8.43 log CFU/g). It was observed that Vibrio species isolated from seawater and sediment were highest in Kuala Sanglang (9.21 log CFU/ml). In Kuala Perlis, the population of Aeromonas isolated from seawater was highest in Jeti (7.94 log CFU/ml). Highest population of Aeromonas from sediment was recorded in Kampong Tanah Baru (7.99 log CFU/g). It was observed that Vibrio species isolated from seawater was highest in Padang Benta (8.42 log CFU/g) while Jeti Kuala Perlis had highest population of Vibrio isolated from sediment. It was observed that location does not influence population of Aeromonas. The results of the independent t - test revealed that there was no significant relationship between location and population of Vibrio (df = 10, t = 1.144, p > 0.05). The occurrence of biofilm formation and prevalence of antibiotic resistant Aeromonas and Vibrio species in seawater and sediment pose danger to human and aquatic animals' health. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Consistency and inconsistency of consensus methods for inferring species trees from gene trees in the presence of ancestral population structure

    Science.gov (United States)

    DeGiorgio, Michael; Rosenberg, Noah A.

    2016-01-01

    In the last few years, several statistically consistent consensus methods for species tree inference have been devised that are robust to the gene tree discordance caused by incomplete lineage sorting in unstructured ancestral populations. One source of gene tree discordance that has only recently been identified as a potential obstacle for phylogenetic inference is ancestral population structure. In this article, we describe a general model of ancestral population structure, and by relying on a single carefully constructed example scenario, we show that the consensus methods Democratic Vote, STEAC, STAR, R* Consensus, Rooted Triple Consensus, Minimize Deep Coalescences, and Majority-Rule Consensus are statistically inconsistent under the model. We find that among the consensus methods evaluated, the only method that is statistically consistent in the presence of ancestral population structure is GLASS/Maximum Tree. We use simulations to evaluate the behavior of the various consensus methods in a model with ancestral population structure, showing that as the number of gene trees increases, estimates on the basis of GLASS/Maximum Tree approach the true species tree topology irrespective of the level of population structure, whereas estimates based on the remaining methods only approach the true species tree topology if the level of structure is low. However, through simulations using species trees both with and without ancestral population structure, we show that GLASS/Maximum Tree performs unusually poorly on gene trees inferred from alignments with little information. This practical limitation of GLASS/Maximum Tree together with the inconsistency of other methods prompts the need for both further testing of additional existing methods and development of novel methods under conditions that incorporate ancestral population structure. PMID:27086043

  6. Impact of forest fragment size on the population structure of three palm species (Arecaceae) in the Brazilian Atlantic rainforest.

    Science.gov (United States)

    Portela, Rita de Cássia Quitete; dos Santos, Flavio Antonio Maes

    2014-06-01

    The main threats to natural populations in terrestrial ecosystems have been widly recognized to be the habitat fragmentation and the exploitation of forest products. In this study, we compared the density of the populations and the structure of three tropical palm species, Astrocaryum aculeatissimum, Euterpe edulis and Geonoma schottiana. For this, we selected five forest fragments of different sizes (3 500ha, 2 400ha, 57ha, 21ha and 19ha) where palms were censused in nine 30 x 30m plots. We tracked the palms survival from 2005 to 2007, and recorded all new individuals encountered. Each individual was assigned in one of the five ontogenetic stages: seedling, infant, juvenile, immature and reproductive. The demographic structure of each palm species was analyzed and compared by a generalized linear model (GLM). The analysis was performed per palm species. The forest fragment area and the year of observation were explanatory variables, and the proportion of individuals in each ontogenetic class and palm density were response variables. The total number of individuals (from seedlings to reproductives, of all species) monitored was 6 450 in 2005, 7 268 in 2006, and 8 664 in 2007. The densities of two palm species were not influenced by the size of the fragment, but the population density of A. aculeatissimum was dependent on the size of the fragment: there were more individuals in the bigger than in the smaller forest fragments. The population structure of A. aculeatissimum, E. edulis, and G. schottiana was not altered in the smaller fragments, except the infants of G. schottiana. The main point to be drawn from the results found in this study is that the responses of density and population structure seem not to be dependent on fragment size, except for one species that resulted more abundant in bigger fragments.

  7. Spontaneous morphogenetic juvenilization observed in laboratory populations of vector species of Chagas disease (Triatominae

    Directory of Open Access Journals (Sweden)

    Alina Perlowagora-Szumlewicz

    1973-08-01

    Full Text Available Reported are observations on spontaneous occurring morphogenetic juvenilization in laboratory populations of vector species of Chagas disease. Two general effects have been observed: arrested development and uncoordinated development. These are manifested by supernumerary nymphs (6th stage, intermediate nymphal-adult stages, badly deformed adults developed from 5th instar nymphs, uncoordinated development manifested by grotesque forms of adults, supernumerary adults unable to complete metamorphosis and complete supernumerary adults produced by 6th stage nymphs. The reoccurrence of insects with identical grades of juvenilization in the population is an indication that this is a genetic trait that might be inherited. The factors responsible for morphogenetic juvenilization cannot be transmitted through the juvenilized insects because they are sterile, than they were transmitted through normal insects probably as a recessive or a group recessive factors. The spontaneous morphogenetic juvenilization observed in laboratory populations has a striking similarity to juvenilizing effects induced by application of juvenile hormone analogues, described in the literature and also obtained in our laboratory in a study to be published. Thus it is suggested that both; the altered phenotypes occurring in wild populations and their "phenocopies" induced by the application of juvenile hormone analogues are products of gene controlled identical reactions.São relatadas observações sobre a ocorrência espontâea de juvenilização morfogenética em populações de espécies transmissoras da doença de Chagas, mantidas no laboratório. Dois efeitos gerais foram observados: a interrupção e a descoordenação do desenvolvimento. Tais efeitos são manifestados: 1 por ninfas supernumerárias (6º estádio, 2 por estágios intermediários (ninfa-adulto, 3 por adultos sensivelmente deformados, provenientes de ninfas do 5º estágio, 4 pelo desenvolvimento d

  8. Reproductive characteristics and population decline of four species of skate (Rajidae) off the eastern coast of Canada.

    Science.gov (United States)

    Mcphie, R P; Campana, S E

    2009-07-01

    Four of the most common species of skate (Rajidae) were studied off eastern Canada to determine if their reproductive characteristics were linked to their population trajectories. The fecundity of the winter skate Leucoraja ocellata, the little skate Leucoraja erinacea, the thorny skate Amblyraja radiata and the smooth skate Malacoraja senta averaged between 41 and 56 egg cases per year for each species. For all species but L. ocellata, males matured at larger sizes and at later ages than females. Theoretical rates of population increase for non-equilibrium populations of L. ocellata (c. 0.07), M. senta (c. 0.14) and L. erinacea and A. radiata (c. 0.20) were low compared to most fishes, indicating that north-west Atlantic skates are intrinsically unproductive, yet are theoretically capable of supporting low-level fisheries. Nevertheless, the results of 36 years of research surveys indicate that the abundance of mature L. ocellata, A. radiata and M. senta all decreased by >90% since 1970, indicating that past fishing mortality (both directed and undirected) has outstripped the net productivity of the skate populations on the eastern Scotian Shelf. The relationship between maximum age (t(max)) and age of maturity (t(mat)) was a better predictor of population growth rate than was body size, with the species exhibiting the highest ratios of t(mat) :t(max) (L. ocellata = 0.68, M. senta = 0.66) having the lowest predicted population growth rates. L. ocellata appears to have the lowest productivity and has experienced the greatest population decline, thus raising concerns over its future status.

  9. Two Positive Periodic Solutions for a Neutral Delay Model of Single-Species Population Growth with Harvesting

    OpenAIRE

    Fang, Hui

    2012-01-01

    By coincidence degree theory for k-set-contractive mapping, this paper establishes a new criterion for the existence of at least two positive periodic solutions for a neutral delay model of single-species population growth with harvesting. An example is given to illustrate the effectiveness of the result.

  10. Two Positive Periodic Solutions for a Neutral Delay Model of Single-Species Population Growth with Harvesting

    Directory of Open Access Journals (Sweden)

    Hui Fang

    2012-01-01

    Full Text Available By coincidence degree theory for k-set-contractive mapping, this paper establishes a new criterion for the existence of at least two positive periodic solutions for a neutral delay model of single-species population growth with harvesting. An example is given to illustrate the effectiveness of the result.

  11. The Multiple Species Inventory and Monitoring Protocol: A Population, Community, and Biodiversity Monitoring Solution for National Forest System Lands

    Science.gov (United States)

    P. N. Manley; B. Van Horne

    2006-01-01

    The U.S. Forest Service manages approximately 76 million ha (191 million acres) of National Forest System (NFS) lands. The National Forest Management Act (1976) recognizes the importance of maintaining species and ecosystem diversity on NFS lands as a critical component of our ecological and cultural heritage. Information on the condition of populations and habitats of...

  12. Temporal Trends in Enterobacter Species Bloodstream Infection: A Population-Based Study, 1998-2007

    Science.gov (United States)

    Al-Hasan, Majdi N.; Lahr, Brian D.; Eckel-Passow, Jeanette E.; Baddour, Larry M.

    2010-01-01

    Enterobacter species are the fourth most common cause of gram-negative bloodstream infection (BSI). We examined temporal changes and seasonal variation in the incidence rate of Enterobacter spp. BSI, estimated 28-day and 1-year mortality, and determined in vitro antimicrobial resistance rates of Enterobacter spp. bloodstream isolates in Olmsted County, Minnesota, from 1/1/1998 to 12/31/2007. Multivariable Poisson regression was used to examine temporal changes and seasonal variation in incidence rate and Kaplan-Meier method to estimate 28-day and 1-year mortality. The median age of patients with Enterobacter spp. BSI was 58 years and 53% were female. The overall age- and gender-adjusted incidence rate of Enterobacter spp. BSI was 3.3/100,000 person-years (95% confidence interval [CI]: 2.3-4.4). There was a linear trend of increasing incidence rate from 0.8 (95% CI: 0-1.9) to 6.2 (95% CI: 3.0-9.3) per 100,000 person-years between 1998 and 2007 (p=0.002). There was no significant difference in the incidence rate of Enterobacter spp. BSI during the warmest four months compared to the remainder of the year (incidence rate ratio 1.06 [95% CI: 0.47-2.01]). The overall 28-day and 1-year mortality rates of Enterobacter spp. BSI were 21% (95% CI: 8-34%) and 38% (95% CI: 22-53%), respectively. Up to 13% of Enterobacter spp. bloodstream isolates were resistant to third-generation cephalosporins. To our knowledge, this is the first population-based study to describe the epidemiology and outcome of Enterobacter spp. BSI. The increase in incidence rate of Enterobacter spp. BSI over the past decade, coupled with its associated antimicrobial resistance, dictate more investigation of this syndrome. PMID:20518795

  13. Population genetic structure of Brazilian shrimp species (Farfantepenaeus sp., F. brasiliensis, F. paulensis and Litopenaeus schmitti: Decapoda: Penaeidae

    Directory of Open Access Journals (Sweden)

    Jaqueline Gusmão

    2005-03-01

    Full Text Available Penaeid shrimps are important resources for worldwide fisheries and aquaculture. In the Southwest Atlantic, Farfantepenaeus brasiliensis, F. paulensis, F. subtilis, Farfantepenaeus sp. and Litopenaeus schmitti are among the most important commercially exploited species. Despite their high commercial value, there is little information available on the different aspects of their biology or genetics and almost no data on their stock structure. We used allozymes to estimate variability levels and population genetic structure of F. brasiliensis, F. paulensis, L. schmitti and the recently detected species Farfantepenaeus sp. along as much as 4,000 km of Brazilian coastline. No population heterogeneity was detected in F. brasiliensis or L. schmitti along the studied area. In contrast, F ST values found for Farfantepenaeus sp. and F. paulensis indicate that the populations of those two species are genetically structured, comprising different fishery stocks. The largest genetic differences in F. paulensis were found between Lagoa dos Patos (South and the two populations from Southeast Brazil. In Farfantepenaeus sp., significant differences were detected between the population from Recife and those from Fortaleza and Ilhéus.

  14. Codivergence and multiple host species use by fig wasp populations of the Ficus pollination mutualism

    Directory of Open Access Journals (Sweden)

    McLeish Michael J

    2012-01-01

    Full Text Available Abstract Background The interaction between insects and plants takes myriad forms in the generation of spectacular diversity. In this association a species host range is fundamental and often measured using an estimate of phylogenetic concordance between species. Pollinating fig wasps display extreme host species specificity, but the intraspecific variation in empirical accounts of host affiliation has previously been underestimated. In this investigation, lineage delimitation and codiversification tests are used to generate and discuss hypotheses elucidating on pollinating fig wasp associations with Ficus. Results Statistical parsimony and AMOVA revealed deep divergences at the COI locus within several pollinating fig wasp species that persist on the same host Ficus species. Changes in branching patterns estimated using the generalized mixed Yule coalescent test indicated lineage duplication on the same Ficus species. Conversely, Elisabethiella and Alfonsiella fig wasp species are able to reproduce on multiple, but closely related host fig species. Tree reconciliation tests indicate significant codiversification as well as significant incongruence between fig wasp and Ficus phylogenies. Conclusions The findings demonstrate more relaxed pollinating fig wasp host specificity than previously appreciated. Evolutionarily conservative host associations have been tempered by horizontal transfer and lineage duplication among closely related Ficus species. Independent and asynchronistic diversification of pollinating fig wasps is best explained by a combination of both sympatric and allopatric models of speciation. Pollinator host preference constraints permit reproduction on closely related Ficus species, but uncertainty of the frequency and duration of these associations requires better resolution.

  15. Phylogeography, colonization and population history of the Midas cichlid species complex (Amphilophus spp. in the Nicaraguan crater lakes

    Directory of Open Access Journals (Sweden)

    Meyer Axel

    2010-10-01

    Full Text Available Abstract Background Elucidation of the mechanisms driving speciation requires detailed knowledge about the phylogenetic relationships and phylogeography of the incipient species within their entire ranges as well as their colonization history. The Midas cichlid species complex Amphilophus spp. has been proven to be a powerful model system for the study of ecological specialization, sexual selection and the mechanisms of sympatric speciation. Here we present a comprehensive and integrative phylogeographic analysis of the complete Midas Cichlid species complex in Nicaragua (> 2000 individuals covering the entire distributional range, using two types of molecular markers (the mitochondrial DNA control region and 15 microsatellites. We investigated the majority of known lake populations of this species complex and reconstructed their colonization history in order to distinguish between alternative speciation scenarios. Results We found that the large lakes contain older and more diverse Midas Cichlid populations, while all crater lakes hold younger and genetically less variable species assemblages. The large lakes appear to have repeatedly acted as source populations for all crater lakes, and our data indicate that faunal exchange among crater lakes is extremely unlikely. Despite their very recent (often only a few thousand years old and common origin from the two large Nicaraguan lakes, all crater lake Midas Cichlid radiations underwent independent, but parallel, evolution, and comprise distinct genetic units. Indeed several of these crater lakes contain multiple genetically distinct incipient species that most likely arose through sympatric speciation. Several crater lake radiations can be traced back to a single ancestral line, but some appear to have more than one founding lineage. The timing of the colonization(s of each crater lake differs, although most of them occurred more (probably much more recently than 20,000 years ago. Conclusion The

  16. Using mitochondrial and nuclear sequence data for disentangling population structure in complex pest species: a case study with Dermanyssus gallinae.

    Directory of Open Access Journals (Sweden)

    Lise Roy

    Full Text Available Among global changes induced by human activities, association of breakdown of geographical barriers and impoverishered biodiversity of agroecosystems may have a strong evolutionary impact on pest species. As a consequence of trade networks' expansion, secondary contacts between incipient species, if hybrid incompatibility is not yet reached, may result in hybrid swarms, even more when empty niches are available as usual in crop fields and farms. By providing important sources of genetic novelty for organisms to adapt in changing environments, hybridization may be strongly involved in the emergence of invasive populations. Because national and international trade networks offered multiple hybridization opportunities during the previous and current centuries, population structure of many pest species is expected to be the most intricate and its inference often blurred when using fast-evolving markers. Here we show that mito-nuclear sequence datasets may be the most helpful in disentangling successive layers of admixture in the composition of pest populations. As a model we used D. gallinae s. l., a mesostigmatid mite complex of two species primarily parasitizing birds, namely D. gallinae L1 and D. gallinae s. str. The latter is a pest species, considered invading layer farms in Brazil. The structure of the pest as represented by isolates from both wild and domestic birds, from European (with a focus on France, Australian and Brazilian farms, revealed past hybridization events and very recent contact between deeply divergent lineages. The role of wild birds in the dissemination of mites appears to be null in European and Australian farms, but not in Brazilian ones. In French farms, some recent secondary contact is obviously consecutive to trade flows. Scenarios of populations' history were established, showing five different combinations of more or less dramatic bottlenecks and founder events, nearly interspecific hybridizations and recent

  17. Connectivity between Migrating and Landlocked Populations of a Diadromous fish Species Investigated Using Otolith Microchemistry

    NARCIS (Netherlands)

    Tulp, I.Y.M.; Keller, A.M.; Navez, J.; Winter, H.V.; Graaf, de M.; Baeyens, W.

    2013-01-01

    Smelt Osmerus eperlanus has two different life history strategies in the Netherlands. The migrating population inhabits the Wadden Sea and spawns in freshwater areas. After the closure of the Afsluitdijk in 1932, part of the smelt population became landlocked. The fresh water smelt population has

  18. 76 FR 9734 - Endangered and Threatened Species; Proposed Threatened Status for Distinct Population Segments of...

    Science.gov (United States)

    2011-02-22

    ... Population Segments of the Bearded Seal AGENCY: National Marine Fisheries Service (NMFS), National Oceanic... December 10, 2010, we, NMFS, published a proposed rule to list the Beringia and Okhotsk Distinct Population..., 2010 (75 FR 77476), we published a proposed rule to list the Beringia and Okhotsk Distinct Population...

  19. Faltering lemming cycles reduce productivity and population size of a migratory Arctic goose species

    NARCIS (Netherlands)

    Nolet, B.A.; Bauer, S.; Feige, N.; Kokorev, Y.; Popov, I.Y.; Ebbinge, B.S.

    2013-01-01

    1. The huge changes in population sizes of Arctic-nesting geese offer a great opportunity to study population limitation in migratory animals. In geese, population limitation seems to have shifted from wintering to summering grounds. There, in the Arctic, climate is rapidly changing, and this may

  20. Population ecology of the sea lamprey (Petromyzon marinus) as an invasive species in the Laurentian Great Lakes and an imperiled species in Europe

    Science.gov (United States)

    Hansen, Michael J.; Madenjian, Charles P.; Slade, Jeffrey W.; Steeves, Todd B.; Almeida, Pedro R.; Quintella, Bernardo R.

    2016-01-01

    The sea lamprey Petromyzon marinus (Linnaeus) is both an invasive non-native species in the Laurentian Great Lakes of North America and an imperiled species in much of its native range in North America and Europe. To compare and contrast how understanding of population ecology is useful for control programs in the Great Lakes and restoration programs in Europe, we review current understanding of the population ecology of the sea lamprey in its native and introduced range. Some attributes of sea lamprey population ecology are particularly useful for both control programs in the Great Lakes and restoration programs in the native range. First, traps within fish ladders are beneficial for removing sea lampreys in Great Lakes streams and passing sea lampreys in the native range. Second, attractants and repellants are suitable for luring sea lampreys into traps for control in the Great Lakes and guiding sea lamprey passage for conservation in the native range. Third, assessment methods used for targeting sea lamprey control in the Great Lakes are useful for targeting habitat protection in the native range. Last, assessment methods used to quantify numbers of all life stages of sea lampreys would be appropriate for measuring success of control in the Great Lakes and success of conservation in the native range.

  1. Developing a protocol for long-term population monitoring and habitat projections for a climate-sensitive sentinel species to track ecosystem change and species range shifts

    Science.gov (United States)

    Beers, A.

    2016-12-01

    As a response to ongoing climate change, many species have started to shift their ranges poleward and toward higher elevations and mountain environments are predicted to experience especially rapid climatic changes. Because of this, there is likely a greater risk of habitat loss and local extinctions for species at high elevations compared to species at lower elevations. Among those potentially threatened habitat specialists is the American pika (Ochotona princeps), a climate sensitive indicator of climate change effects which may already be experiencing climate driven extirpations. Pikas are considered sentinels, indicators of greater ecosystem change. Changes in their distribution speaks to changes in availability of resources they require and shifts in the environment. Pika presence is closely tied to sub-surface ice features that act as a temperature buffer and water source. Those sub-surface ice features are critical in water cycling and long-term water storage and drive downstream hydrological and ecological processes. Understanding how this species responds to climate change therefore provides a model to inform landscape level conservation and management decisions. Pikas may be particularly vulnerable in parts of Colorado, including Rocky Mountain National Park (ROMO) and the Niwot Ridge LTER (NWT), where they may face population collapse as habitat suitability and connectivity both decline in response to various possible climate change scenarios, in large part because of cold stress and declining functional connectivity. Because of their potential role as an ecosystem indicator, their risk for decline, and how limitations to their survival likely vary across their range, management groups can use place based models of habitat suitability for pikas or other sentinel species in designing long term monitoring protocols to detect ecosystem responses to climate change. In this project we used remotely sensed data, occupancy surveys, and a random tessellation

  2. Energy brands lack vitality

    International Nuclear Information System (INIS)

    Godri, S.; Wilders, E.

    2004-01-01

    The three Dutch energy companies (Nuon, Essent and Eneco Energie) have relatively little brand strength. The brands are not perceived to be sufficiently different from one another and are not valued by consumers. With liberalisation imminent, this is hardly a strong starting point. How can you win over consumers if it is not clear what is on offer? In the business market, decision-makers are better placed to distinguish between brands. However, the brands lack vitality in this sector of the market too. The only consolation is that the situation is by no means exclusive to the Netherlands [nl

  3. The population genomic signature of environmental association and gene flow in an ecologically divergent tree species Metrosideros polymorpha (Myrtaceae).

    Science.gov (United States)

    Izuno, Ayako; Kitayama, Kanehiro; Onoda, Yusuke; Tsujii, Yuki; Hatakeyama, Masaomi; Nagano, Atsushi J; Honjo, Mie N; Shimizu-Inatsugi, Rie; Kudoh, Hiroshi; Shimizu, Kentaro K; Isagi, Yuji

    2017-03-01

    Genomewide markers enable us to study genetic differentiation within a species and the factors underlying it at a much higher resolution than before, which advances our understanding of adaptation in organisms. We investigated genomic divergence in Metrosideros polymorpha, a woody species that occupies a wide range of ecological habitats across the Hawaiian Islands and shows remarkable phenotypic variation. Using 1659 single nucleotide polymorphism (SNP) markers annotated with the genome assembly, we examined the population genetic structure and demographic history of nine populations across five elevations and two ages of substrates on Mauna Loa, the island of Hawaii. The nine populations were differentiated into two genetic clusters distributed on the lower and higher elevations and were largely admixed on the middle elevation. Demographic modelling revealed that the two genetic clusters have been maintained in the face of gene flow, and the effective population size of the high-altitude cluster was much smaller. A F ST -based outlier search among the 1659 SNPs revealed that 34 SNPs (2.05%) were likely to be under divergent selection and the allele frequencies of 21 of them were associated with environmental changes along elevations, such as temperature and precipitation. This study shows a genomic mosaic of M. polymorpha, in which contrasting divergence patterns were found. While most genomic polymorphisms were shared among populations, a small fraction of the genome was significantly differentiated between populations in diverse environments and could be responsible for the dramatic adaptation to a wide range of environments. © 2017 John Wiley & Sons Ltd.

  4. The Use of Carcasses for the Analysis of Cetacean Population Genetic Structure: A Comparative Study in Two Dolphin Species

    Science.gov (United States)

    Bilgmann, Kerstin; Möller, Luciana M.; Harcourt, Robert G.; Kemper, Catherine M.; Beheregaray, Luciano B.

    2011-01-01

    Advances in molecular techniques have enabled the study of genetic diversity and population structure in many different contexts. Studies that assess the genetic structure of cetacean populations often use biopsy samples from free-ranging individuals and tissue samples from stranded animals or individuals that became entangled in fishery or aquaculture equipment. This leads to the question of how representative the location of a stranded or entangled animal is with respect to its natural range, and whether similar results would be obtained when comparing carcass samples with samples from free-ranging individuals in studies of population structure. Here we use tissue samples from carcasses of dolphins that stranded or died as a result of bycatch in South Australia to investigate spatial population structure in two species: coastal bottlenose (Tursiops sp.) and short-beaked common dolphins (Delphinus delphis). We compare these results with those previously obtained from biopsy sampled free-ranging dolphins in the same area to test whether carcass samples yield similar patterns of genetic variability and population structure. Data from dolphin carcasses were gathered using seven microsatellite markers and a fragment of the mitochondrial DNA control region. Analyses based on carcass samples alone failed to detect genetic structure in Tursiops sp., a species previously shown to exhibit restricted dispersal and moderate genetic differentiation across a small spatial scale in this region. However, genetic structure was correctly inferred in D. delphis, a species previously shown to have reduced genetic structure over a similar geographic area. We propose that in the absence of corroborating data, and when population structure is assessed over relatively small spatial scales, the sole use of carcasses may lead to an underestimate of genetic differentiation. This can lead to a failure in identifying management units for conservation. Therefore, this risk should be carefully

  5. Population dynamics of the species Plantago major L. and Poa annua L. in a replacement series experiment

    Directory of Open Access Journals (Sweden)

    Mijović A.

    2009-01-01

    Full Text Available Population dynamics of the species Plantago major L. and Poa annua L., typical representatives of ruderal vegetation, was analyzed in a replacement series experiment. The analyzed species were sown in an area with meadow vegetation, where the vegetation present had been previously removed by a total herbicide and additionally by hoeing. The objective of the experiment was to monitor growth dynamics and the effect of intra- and inter-specific interaction of the species Plantago major and Poa annua in conditions of different sowing densities and proportions. The effects of intra- and inter-specific interference and the density-dependent responses were assessed on the basis of several parameters (natality, mortality, age structure, and measures of ontogenetic changes. Based on the study results, it can be concluded that the responses of the species in the experiment were different, which is explained by different adaptive mechanisms, i.e., strategies, in the specific environmental conditions. An effect of the density dependent response was present in both species in the replacement series experiment. The response was amplified by water deficit caused by intensive evapora­tion of the bare soil. No effect of inter-specific interference was observed at the given densities of the study species on the sample plots. An effect of intra-specific interference of the species Plantago major and Poa annua was observed in the guise of a density-negative response of the rate of ontogenetic changes and fecundity.

  6. Assessing three fish species ecological status in Colorado River, Grand Canyon based on physical habitat and population models.

    Science.gov (United States)

    Yao, Weiwei; Chen, Yuansheng

    2018-04-01

    Colorado River is a unique ecosystem and provides important ecological services such as habitat for fish species as well as water power energy supplies. River management for this ecosystem requires assessment and decision support tools for fish which involves protecting, restoring as well as forecasting of future conditions. In this paper, a habitat and population model was developed and used to determine the levels of fish habitat suitability and population density in Colorado River between Lees Ferry and Lake Mead. The short term target fish populations are also predicted based on native fish recovery strategy. This model has been developed by combining hydrodynamics, heat transfer and sediment transport models with a habitat suitability index model and then coupling with habitat model into life stage population model. The fish were divided into four life stages according to the fish length. Three most abundant and typical native and non-native fish were selected as target species, which are rainbow trout (Oncorhynchus mykiss), brown trout (Salmo trutta) and flannelmouth sucker (Catostomus latipinnis). Flow velocity, water depth, water temperature and substrates were used as the suitability indicators in habitat model and overall suitability index (OSI) as well as weight usable area (WUA) was used as an indicator in population model. A comparison was made between simulated fish population alteration and surveyed fish number fluctuation during 2000 to 2009. The application of this habitat and population model indicates that this model can be accurate present habitat situation and targets fish population dynamics of in the study areas. The analysis also indicates the flannelmouth sucker population will steadily increase while the rainbow trout will decrease based on the native fish recovery scheme. Copyright © 2018. Published by Elsevier Inc.

  7. Permanent colonization of creek sediments, creek water and limnic water plants by four Listeria species in low population densities.

    Science.gov (United States)

    Lang-Halter, Evi; Schober, Steffen; Scherer, Siegfried

    2016-09-01

    During a 1-year longitudinal study, water, sediment and water plants from two creeks and one pond were sampled monthly and analyzed for the presence of Listeria species. A total of 90 % of 30 sediment samples, 84 % of 31 water plant samples and 67 % of 36 water samples were tested positive. Generally, most probable number counts ranged between 1 and 40 g-1, only occasionally >110 cfu g-1 were detected. Species differentiation based on FT-IR spectroscopy and multiplex PCR of a total of 1220 isolates revealed L. innocua (46 %), L. seeligeri (27 %), L. monocytogenes (25 %) and L. ivanovii (2 %). Titers and species compositions were similar during all seasons. While the species distributions in sediments and associated Ranunculus fluitans plants appeared to be similar in both creeks, RAPD typing did not provide conclusive evidence that the populations of these environments were connected. It is concluded that (i) the fresh-water sediments and water plants are year-round populated by Listeria, (ii) no clear preference for growth in habitats as different as sediments and water plants was found and (iii) the RAPD-based intraspecific biodiversity is high compared to the low population density.

  8. Gene Flow among Populations of Two Rare Co-Occurring Fern Species Differing in Ploidy Level

    Czech Academy of Sciences Publication Activity Database

    Bucharová, Anna; Münzbergová, Zuzana

    2012-01-01

    Roč. 7, č. 9 (2012), e45855 E-ISSN 1932-6203 R&D Projects: GA MŠk 2B06178; GA ČR GA526/09/0549 Institutional support: RVO:67985939 Keywords : genetic variation * tetraploid species * diploid species Subject RIV: EF - Botanics Impact factor: 3.730, year: 2012

  9. The roles of competition and habitat in the dynamics of populations and species distributions Ecology

    Science.gov (United States)

    Charles B. Yackulic; Janice Reid; James D. Nichols; James E. Hines; Raymond Davis; Eric Forsman

    2014-01-01

    The role of competition in structuring biotic communities at fine spatial scales is well known from detailed process-based studies. Our understanding of competition’s importance at broader scales is less resolved and mainly based on static species distribution maps. Here, we bridge this gap by examining the joint occupancy dynamics of an invading species (Barred Owl,...

  10. Population genetics of Phaedranassa cuencana Minga, C. Ulloa & Oleas (Amaryllidaceae), an endemic species of Southern Ecuador

    Science.gov (United States)

    Phaedranassa is a genus of Amaryllidaceae mostly endemic to the Northern Andes. Six out of the eight species described in Ecuador are endangered or vulnerable to extinction. Phaedranassa cuencana was first described in 2015. This species is restricted to the southern part of Ecuador, around the city...

  11. The seabird paradox: dispersal, genetic structure and population dynamics in a highly mobile, but philopatric albatross species.

    Science.gov (United States)

    Milot, Emmanuel; Weimerskirch, Henri; Bernatchez, Louis

    2008-04-01

    The philopatric behaviour of albatrosses has intrigued biologists due to the high mobility of these seabirds. It is unknown how albatrosses maintain a system of fragmented populations without frequent dispersal movements, in spite of the long-term temporal heterogeneity in resource distribution at sea. We used both genetic (amplified fragment length polymorphism) and capture-mark-recapture (CMR) data to identify explicitly which among several models of population dynamics best applies to the wandering albatross (Diomedea exulans) and to test for migration-drift equilibrium. We previously documented an extremely low genetic diversity in this species. Here, we show that populations exhibit little genetic differentiation across the species' range (Theta(B) albatross. Yet, our data suggest that several other factors including ongoing gene flow, recurrent long-distance dispersal and source-sink dynamics have contributed to different extent in shaping the genetic signature observed in this species. Our results show that an absence of genetic structuring may in itself reveal little about the true population dynamics in seabirds, but can provide insights into important processes when a comparison with other information, such as demographic data, is possible.

  12. Comparison of phylogeographic structure and population history of two Phrynocephalus species in the Tarim Basin and adjacent areas.

    Science.gov (United States)

    Zhang, Qian; Xia, Lin; He, Jingbo; Wu, Yonghua; Fu, Jinzhong; Yang, Qisen

    2010-12-01

    An aridification of the Tarim Basin and adjacent areas since middle Pleistocene has produced significant genetic structuring of the local fauna. We examined the phylogeographic patterns, population structure and history of Phrynocephalus axillaris and Phrynocephalus forsythii using a mitochondrial fragment ND4-tRNA(LEU). Phylogenetic hypotheses were constructed using maximum parsimony and Bayesian inference, and the divergence times of major lineages were estimated by BEAST. Population structure and history were inferred by nested clade analysis, neutrality tests, mismatch distribution, and isolation by distance analysis. The two species might have experienced different evolutionary history throughout their current distribution. For P. forsythii, a vicariant event, as a consequence of geological isolation and desert expansion, might have produced the significant divergence between the Tarim and the Yanqi populations. For P. axillaris, populations of the Yanqi, Turpan and Hami Basins might have been established through dispersal during demographic expansion. Climatic fluctuations caused alternate expansion and shrinkage of rivers and oases several times, which likely led to habitat fragmentation for both species. Interaction between vicariance, dispersal and habitat fragmentation produced the current distribution and genetic diversity. The observed difference between the two species may be due partially to their different reproductive modes (ovoviviparous vs. oviparous). Copyright © 2010 Elsevier Inc. All rights reserved.

  13. Genetic structure and effective population size through time: a tale on two coastal marine species with contrasting life-history patterns

    Directory of Open Access Journals (Sweden)

    Sara Martins Francisco

    2015-12-01

    Full Text Available Species with dispersal mediated by planktonic larvae are expected to be more likely to show temporal genetic variation, due to differences in larval mortality and dispersal ability. The shanny Lipophrys pholis is a typical benthic rocky intertidal fish and its dispersion is limited to its long larval stage. In contrast, the sand-smelt Atherina presbyter has a very short planktonic life, small size and weak swimming capabilities, which translates into reduced dispersion potential. A total of 226 specimens of L. pholis (collected in 2003, 2013 and 2014 and 281 of A. presbyter (collected in 2005, 2012, 2013 and 2014 were screened for genetic variation using the mitochondrial control region. Only 12 (out of 171 and 25 (out of 155 haplotypes found were shared between sampling periods for the shanny and the sand smelt, respectively. For both species, haplotype networks showed a deep genealogy with multiple levels of diversification and no temporal structure. Interestingly, some of the previously inferred missing haplotypes were sampled in more recent years. The genetic diversity indices showed little variation among sampling periods and were generally high. For L. pholis significant genetic differentiation was detected between 2013 and 2014, while no significant differences were detected between sampling periods in A. presbyter. The shanny showed lower effective population size per generation when compared to the sand-smelt (which yielded lack of evidence for genetic drift for the first and second period of the study. These results highlight the fact that temporal changes in the gene pool composition need to be considered when evaluating population structure, especially for species with long pelagic larval dispersion, more vulnerable to fluctuations in the recruitment.

  14. High-utility conserved avian microsatellite markers enable parentage and population studies across a wide range of species

    Science.gov (United States)

    2013-01-01

    reduce the necessity and expense of microsatellite isolation for a wide range of genetic studies, including avian parentage and population analyses, but will also now enable comparisons of genetic diversity among different species (and populations) at the same set of loci, with no or reduced bias. Finally, the approach used here can be applied to other taxa in which appropriate genome sequences are available. PMID:23497230

  15. Field studies on populations of Aedes albopictus and Toxorhynchites species in bamboo pots in Malaysia.

    Science.gov (United States)

    Sulaiman, S; Jeffery, J

    1994-09-01

    Between April 1987 and March 1988, populations of immature Aedes albopictus and Toxorhynchites spp. in bamboo pots were sampled weekly. Populations of Ae. albopictus and rainfall varied from month to month. During the heavy rainfall months of September and October 1987, larval counts of Ae. albopictus were high, between 30.8 and 49.2 larvae per week compared to 16 larvae per week during the low rainfall month of January 1988. A higher population of Toxorhynchites spp. was associated with a low population of the vector.

  16. Connectivity between migrating and landlocked populations of a diadromous fish species investigated using otolith microchemistry.

    Directory of Open Access Journals (Sweden)

    Ingrid Tulp

    Full Text Available Smelt Osmerus eperlanus has two different life history strategies in The Netherlands. The migrating population inhabits the Wadden Sea and spawns in freshwater areas. After the closure of the Afsluitdijk in 1932, part of the smelt population became landlocked. The fresh water smelt population has been in severe decline since 1990, and has strongly negatively impacted the numbers of piscivorous water birds relying on smelt as their main prey. The lakes that were formed after the dike closure, IJsselmeer and Markermeer have been assigned as Natura 2000 sites, based on their importance for (among others piscivorous water birds. Because of the declining fresh water smelt population, the question arose whether this population is still supported by the diadromous population. Opportunities for exchange between fresh water and the sea are however limited to discharge sluices. The relationship between the diadromous and landlocked smelt population was analysed by means of otolith microchemistry. Our interpretation of otolith strontium ((88Sr patterns from smelt specimens collected in the fresh water area of Lake IJsselmeer and Markermeer, compared to those collected in the nearby marine environment, is that there is currently no evidence for a substantial contribution from the diadromous population to the spawning stock of the landlocked population.

  17. 78 FR 3381 - Endangered and Threatened Species: Designation of a Nonessential Experimental Population of...

    Science.gov (United States)

    2013-01-16

    ... comments will be accepted in Microsoft Word, Excel, or Adobe PDF file formats only. You may access a copy... Endangered and threatened species, Exports, Imports. For the reasons set out in the preamble, we propose to...

  18. Population Connectivity Measures of Fishery-Targeted Coral Reef Species to Inform Marine Reserve Network Design in Fiji.

    Science.gov (United States)

    Eastwood, Erin K; López, Elora H; Drew, Joshua A

    2016-01-25

    Coral reef fish serve as food sources to coastal communities worldwide, yet are vulnerable to mounting anthropogenic pressures like overfishing and climate change. Marine reserve networks have become important tools for mitigating these pressures, and one of the most critical factors in determining their spatial design is the degree of connectivity among different populations of species prioritized for protection. To help inform the spatial design of an expanded reserve network in Fiji, we used rapidly evolving mitochondrial genes to investigate connectivity patterns of three coral reef species targeted by fisheries in Fiji: Epinephelus merra (Serranidae), Halichoeres trimaculatus (Labridae), and Holothuria atra (Holothuriidae). The two fish species, E. merra and Ha. trimaculatus, exhibited low genetic structuring and high amounts of gene flow, whereas the sea cucumber Ho. atra displayed high genetic partitioning and predominantly westward gene flow. The idiosyncratic patterns observed among these species indicate that patterns of connectivity in Fiji are likely determined by a combination of oceanographic and ecological characteristics. Our data indicate that in the cases of species with high connectivity, other factors such as representation or political availability may dictate where reserves are placed. In low connectivity species, ensuring upstream and downstream connections is critical.

  19. Inbreeding and gene flow : the population genetics of plant species in fragmented landscapes

    NARCIS (Netherlands)

    Mix, Carolin

    2006-01-01

    Habitat fragmentation has been recognized as one of the major threats to plant population persistence. Fragmented small and isolated populations are expected to be seriously affected by inbreeding and genetic drift. Gene flow through seed and pollen dispersal may counterbalance the negative

  20. Population Structure of the Greenhouse Whitefly, Trialeurodes vaporariorum (Westwood, an Invasive Species from the Americas, 60 Years after Invading China

    Directory of Open Access Journals (Sweden)

    Rui-Rui Gao

    2014-08-01

    Full Text Available Though the greenhouse whitefly, Trialeurodes vaporariorum (Westwood (Hemiptera: Aleyrodidae was introduced into China more than 60 years ago, the genetic diversity and structure of this exotic insect pest and virus vector have not been studied. To investigate the population genetic characteristics of this invasive species and to identify potential invasion routes, the genetic diversity and population structure of 17 collections of T. vaporariorum from nine provinces in China were analyzed using seven microsatellite loci. The results of the analyses indicated that the genetic diversity for the populations examined from the four provinces: Jilin, Ningxia, Guizhou and Qinghai, was lower than the genetic diversity of populations from the five provinces: Yunnan, Shandong, Shanxi, Liaoning, and Gansu. The T. vaporariorum populations analyzed in this study grouped as two distinct genetic clusters based on the analysis using STRUCTURE, whereas, 8 clusters were identified based on the BAPS analysis. Of the 136 genetic distance (Fst values, 128 (94% were associated with a significant exact test. However, there was no significant relationship between Fst and geographical distance. These results demonstrate that populations of T. vaporariorum in China exhibit significant genetic differentiation, indicating the likelihood that multiple introductions of T. vaporariorum into China have occurred. Also, the populations collected from the provinces of Jilin, Ningxia, Guizhou and Qinghai appear to represent secondary introductions originating from other Chinese provinces.

  1. Winter Activity of Coastal Plain Populations of Bat Species Affected by White-Nose Syndrome and Wind Energy Facilities.

    Science.gov (United States)

    Grider, John F; Larsen, Angela L; Homyack, Jessica A; Kalcounis-Rueppell, Matina C

    2016-01-01

    Across the entire distribution of a species, populations may have variable responses to environmental perturbations. Many bat species experience mortality in large portions of their range during hibernation and along migratory paths to and from wintering grounds, from White-nose syndrome (WNS) and wind energy development, respectively. In some areas, warm temperatures may allow bats to remain active through winter, thus decreasing their susceptibility to WNS and/or mortality associated with migration to wintering grounds. These areas could act as a refugia and be important for the persistence of local populations. To determine if warmer temperatures affect bat activity, we compared year-round activity of bat populations in the Coastal Plain and Piedmont of North Carolina, USA, two regions that differ in winter temperature. We established six recording stations, four along a 295-kilometer north-south transect in the Coastal Plain, and two in the Piedmont of North Carolina. We recorded bat activity over two years. We supplemented our recordings with mist-net data. Although bat activity was lower during winter at all sites, the odds of recording a bat during winter were higher at Coastal Plain sites when compared with Piedmont sites. Further, bats in the Piedmont had a lower level of winter activity compared to summer activity than bats in the Coastal Plain that had more similar levels of activity in the winter and summer. We found high bat species richness on the Coastal Plain in winter, with winter-active species including those known to hibernate throughout most of their range and others known to be long distance migrants. In particular, two species impacted by WNS, the northern long-eared bat (Myotis septentrionalis) and tricolored bat (Perimyotis subflavus), were present year round in the Coastal Plain. The tricolored bat was also present year-round in the Piedmont. In the Coastal Plain, the long distance migratory hoary bat (Lasiurus cinereus) was active in the

  2. Winter Activity of Coastal Plain Populations of Bat Species Affected by White-Nose Syndrome and Wind Energy Facilities.

    Directory of Open Access Journals (Sweden)

    John F Grider

    Full Text Available Across the entire distribution of a species, populations may have variable responses to environmental perturbations. Many bat species experience mortality in large portions of their range during hibernation and along migratory paths to and from wintering grounds, from White-nose syndrome (WNS and wind energy development, respectively. In some areas, warm temperatures may allow bats to remain active through winter, thus decreasing their susceptibility to WNS and/or mortality associated with migration to wintering grounds. These areas could act as a refugia and be important for the persistence of local populations. To determine if warmer temperatures affect bat activity, we compared year-round activity of bat populations in the Coastal Plain and Piedmont of North Carolina, USA, two regions that differ in winter temperature. We established six recording stations, four along a 295-kilometer north-south transect in the Coastal Plain, and two in the Piedmont of North Carolina. We recorded bat activity over two years. We supplemented our recordings with mist-net data. Although bat activity was lower during winter at all sites, the odds of recording a bat during winter were higher at Coastal Plain sites when compared with Piedmont sites. Further, bats in the Piedmont had a lower level of winter activity compared to summer activity than bats in the Coastal Plain that had more similar levels of activity in the winter and summer. We found high bat species richness on the Coastal Plain in winter, with winter-active species including those known to hibernate throughout most of their range and others known to be long distance migrants. In particular, two species impacted by WNS, the northern long-eared bat (Myotis septentrionalis and tricolored bat (Perimyotis subflavus, were present year round in the Coastal Plain. The tricolored bat was also present year-round in the Piedmont. In the Coastal Plain, the long distance migratory hoary bat (Lasiurus cinereus

  3. Phylogenetic patterns in populations of Chilean species of the genus Orestias (Teleostei: Cyprinodontidae): results of mitochondrial DNA analysis.

    Science.gov (United States)

    Lüssen, Arne; Falk, Thomas M; Villwock, Wolfgang

    2003-10-01

    Patterns of molecular genetic differentiation among taxa of the "agassii species complex" (Parenti, 1984) were analysed based on partial mtDNA control region sequences. Special attention has been paid to Chilean populations of Orestias agassii and species from isolated lakes of northern Chile, e.g., O. agassii, Orestias chungarensis, Orestias parinacotensis, Orestias laucaensis, and Orestias ascotanensis. Orestias tschudii, Orestias luteus, and Orestias ispi were analysed comparatively. Our findings support the utility of mtDNA control region sequences for phylogenetic studies within the "agassii species complex" and confirmed the monophyly of this particular lineage, excluding O. luteus. However, the monophyly of further morphologically defined lineages within the "agassii complex" appears doubtful. No support was found for the utility of these data sets for inferring phylogenetic relationships between more distantly related taxa originating from Lake Titicaca.

  4. Philodendron williamsii Hook. f. (Araceae, an endemic and vulnerable species of southern Bahia, Brazil used for local population

    Directory of Open Access Journals (Sweden)

    L.S.B. Calazans

    2012-12-01

    Full Text Available An updated description and information on ecology, geographical distribution, ethnobiology, uses and conservation of Philodendron williamsii are presented here. The species has a restricted geographical distribution and the roots of its natural populations are widely extracted to be used for local handicraft. During the fertile period of the plant, areas where the species grow were prospected in order to collect, observe, photograph and consult people who directly use parts of the plants. Additional specimens from five herbaria were analyzed. We propose the inclusion of the species as Vulnerable based on the categories and the criteria proposed by the IUCN. Environmental education for the local extractors and the regularization of its extractive activity are suggested here.

  5. In-vitro activity of taurolidine on single species and a multispecies population associated with periodontitis.

    Science.gov (United States)

    Zollinger, Lilly; Schnyder, Simone; Nietzsche, Sandor; Sculean, Anton; Eick, Sigrun

    2015-04-01

    The antimicrobial activity of taurolidine was compared with minocycline against microbial species associated with periodontitis (four single strains and a 12-species mixture). Minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs), killing as well as activities on established and forming single-species biofilms and a 12-species biofilm were determined. The MICs of taurolidine against single species were always 0.31 mg/ml, the MBCs were 0.64 mg/ml. The used mixed microbiota was less sensitive to taurolidine, MIC and the MBC was 2.5 mg/ml. The strains and the mixture were completely killed by 2.5 mg/ml taurolidine, whereas 256 μg/ml minocycline reduced the bacterial counts of the mixture by 5 log10 colony forming units (cfu). Coating the surface with 10 mg/ml taurolidine or 256 μg/ml minocycline prevented completely biofilm formation of Porphyromonas gingivalis ATCC 33277 but not of Aggregatibacter actinomycetemcomitans Y4 and the mixture. On 4.5 d old biofilms, taurolidine acted concentration dependent with a reduction by 5 log10 cfu (P. gingivalis ATCC 33277) and 7 log10 cfu (A. actinomycetemcomitans Y4) when applying 10 mg/ml. Minocycline decreased the cfu counts by 1-2 log10 cfu independent of the used concentration. The reduction of the cfu counts in the 4.5 d old multi-species biofilms was about 3 log10 cfu after application of any minocycline concentration and after using 10 mg/ml taurolidine. Taurolidine is active against species associated with periodontitis, even within biofilms. Nevertheless a complete elimination of complex biofilms by taurolidine seems to be impossible and underlines the importance of a mechanical removal of biofilms prior to application of taurolidine. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Molecular Diversity of Anthracnose Pathogen Populations Associated with UK Strawberry Production Suggests Multiple Introductions of Three Different Colletotrichum Species.

    Science.gov (United States)

    Baroncelli, Riccardo; Zapparata, Antonio; Sarrocco, Sabrina; Sukno, Serenella A; Lane, Charles R; Thon, Michael R; Vannacci, Giovanni; Holub, Eric; Sreenivasaprasad, Surapareddy

    2015-01-01

    Fragaria × ananassa (common name: strawberry) is a globally cultivated hybrid species belonging to Rosaceae family. Colletotrichum acutatum sensu lato (s.l.) is considered to be the second most economically important pathogen worldwide affecting strawberries. A collection of 148 Colletotrichum spp. isolates including 67 C. acutatum s.l. isolates associated with the phytosanitary history of UK strawberry production were used to characterize multi-locus genetic variation of this pathogen in the UK, relative to additional reference isolates that represent a worldwide sampling of the diversity of the fungus. The evidence indicates that three different species C. nymphaeae, C. godetiae and C. fioriniae are associated with strawberry production in the UK, which correspond to previously designated genetic groups A2, A4 and A3, respectively. Among these species, 12 distinct haplotypes were identified suggesting multiple introductions into the country. A subset of isolates was also used to compare aggressiveness in causing disease on strawberry plants and fruits. Isolates belonging to C. nymphaeae, C. godetiae and C. fioriniae representative of the UK anthracnose pathogen populations showed variation in their aggressiveness. Among the three species, C. nymphaeae and C. fioriniae appeared to be more aggressive compared to C. godetiae. This study highlights the genetic and pathogenic heterogeneity of the C. acutatum s.l. populations introduced into the UK linked to strawberry production.

  7. Molecular Diversity of Anthracnose Pathogen Populations Associated with UK Strawberry Production Suggests Multiple Introductions of Three Different Colletotrichum Species.

    Directory of Open Access Journals (Sweden)

    Riccardo Baroncelli

    Full Text Available Fragaria × ananassa (common name: strawberry is a globally cultivated hybrid species belonging to Rosaceae family. Colletotrichum acutatum sensu lato (s.l. is considered to be the second most economically important pathogen worldwide affecting strawberries. A collection of 148 Colletotrichum spp. isolates including 67 C. acutatum s.l. isolates associated with the phytosanitary history of UK strawberry production were used to characterize multi-locus genetic variation of this pathogen in the UK, relative to additional reference isolates that represent a worldwide sampling of the diversity of the fungus. The evidence indicates that three different species C. nymphaeae, C. godetiae and C. fioriniae are associated with strawberry production in the UK, which correspond to previously designated genetic groups A2, A4 and A3, respectively. Among these species, 12 distinct haplotypes were identified suggesting multiple introductions into the country. A subset of isolates was also used to compare aggressiveness in causing disease on strawberry plants and fruits. Isolates belonging to C. nymphaeae, C. godetiae and C. fioriniae representative of the UK anthracnose pathogen populations showed variation in their aggressiveness. Among the three species, C. nymphaeae and C. fioriniae appeared to be more aggressive compared to C. godetiae. This study highlights the genetic and pathogenic heterogeneity of the C. acutatum s.l. populations introduced into the UK linked to strawberry production.

  8. Dispersal, dormancy and life-history tradeoffs at the individual, population and species levels in southern African Asteraceae.

    Science.gov (United States)

    de Waal, Caroli; Anderson, Bruce; Ellis, Allan G

    2016-04-01

    Dispersal and dormancy are important risk-reducing strategies in unpredictable environments. Negative covariation between these strategies is theoretically expected, but empirical evidence is limited and inconsistent. Moreover, covariation may be affected by other life-history traits and may vary across levels of biological organization. We assessed dispersal (vertical fall time of fruits, a proxy for wind dispersal ability) and dormancy (germination fractions measured during germination trials) in populations of 15 annual and 12 perennial wind-dispersed species in six Asteraceae genera from South Africa. Dormancy was higher in annuals than in perennials, whereas fall time was largely determined by evolutionary history. Controlling for phylogeny, dispersal and dormancy was negatively associated across species and life-history categories. Negative covariation between dispersal and dormancy was not evident at either the individual level (except for seed heteromorphic species) or the population level. Our study provides rare empirical support for the theoretical expectation of tradeoffs between dormancy and the alternative risk-reducing strategies, perenniality and dispersal, but refutes the expectation of increased dispersability in perennials. Although negative covariation between dispersal and dormancy at the species level appears not to be a simple consequence of upscaling individual-level mechanistic tradeoffs, our findings suggest that selection for one strategy may constrain evolution of the other. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  9. Genetic population structure of three Armillaria species at the landscape scale: a case study from Swiss Pinus mugo forests.

    Science.gov (United States)

    Bendel, Muriel; Kienast, Felix; Rigling, Daniel

    2006-06-01

    Armillaria species are plant pathogens that cause Armillaria root rot and are known to cause mortality of mountain pines (Pinus mugo) in the Swiss National Park in the Central Alps. The identity of isolates and the spatially explicit population structure of the Armillaria species were investigated in a 3.3km(2) study area in the Swiss National Park. In total, 242 Armillaria isolates, 205 from wood samples and 37 from epiphytic rhizomorphs, were collected. Species were identified using haploid-diploid pairings and genets were determined using intraspecific somatic incompatibility tests. The population structure differed markedly among the Armillaria species. A. cepistipes and A. borealis mainly occurred as genets of small spatial extent (mean 0.2ha, and 0.6ha), whereas A. ostoyae formed significantly larger genets (mean 6.8ha). The largest A. ostoyae genet extended over approx. 37ha. Several disease centres associated with Heterobasidion annosum were found to be embedded within large Armillaria genets. The extension of large A. ostoyae genets suggests that forests that occupy the study area have developed in the presence of these Armillaria genets. The finding of large Armillaria genets supports the assumption that large genets occur in areas with cold climate and little precipitation.

  10. Molecular Diversity of Anthracnose Pathogen Populations Associated with UK Strawberry Production Suggests Multiple Introductions of Three Different Colletotrichum Species

    Science.gov (United States)

    Baroncelli, Riccardo; Zapparata, Antonio; Sarrocco, Sabrina; Sukno, Serenella A.; Lane, Charles R.; Thon, Michael R.; Vannacci, Giovanni; Holub, Eric; Sreenivasaprasad, Surapareddy

    2015-01-01

    Fragaria × ananassa (common name: strawberry) is a globally cultivated hybrid species belonging to Rosaceae family. Colletotrichum acutatum sensu lato (s.l.) is considered to be the second most economically important pathogen worldwide affecting strawberries. A collection of 148 Colletotrichum spp. isolates including 67 C. acutatum s.l. isolates associated with the phytosanitary history of UK strawberry production were used to characterize multi-locus genetic variation of this pathogen in the UK, relative to additional reference isolates that represent a worldwide sampling of the diversity of the fungus. The evidence indicates that three different species C. nymphaeae, C. godetiae and C. fioriniae are associated with strawberry production in the UK, which correspond to previously designated genetic groups A2, A4 and A3, respectively. Among these species, 12 distinct haplotypes were identified suggesting multiple introductions into the country. A subset of isolates was also used to compare aggressiveness in causing disease on strawberry plants and fruits. Isolates belonging to C. nymphaeae, C. godetiae and C. fioriniae representative of the UK anthracnose pathogen populations showed variation in their aggressiveness. Among the three species, C. nymphaeae and C. fioriniae appeared to be more aggressive compared to C. godetiae. This study highlights the genetic and pathogenic heterogeneity of the C. acutatum s.l. populations introduced into the UK linked to strawberry production. PMID:26086351

  11. Effects of climate change on a mutualistic coastal species: Recovery from typhoon damages and risks of population erosion.

    Directory of Open Access Journals (Sweden)

    Yu-Ting Chiu

    Full Text Available Presently, climate change has increased the frequency of extreme meteorological events such as tropical cyclones. In the western Pacific basin, these cyclones are called typhoons, and in this area, around Taiwan Island, their frequency has almost doubled since 2000. When approaching landmasses, typhoons have devastating effects on coastal vegetation. The increased frequency of these events has challenged the survival of coastal plant species and their posttyphoon recovery. In this study, a population of coastal gynodioecious Ficus pedunculosa var. mearnsii (Mearns fig was surveyed for two years to investigate its recovery after Typhoon Morakot, which occurred in August 2009. Similar to all the Ficus species, the Mearns fig has an obligate mutualistic association with pollinating fig wasp species, which requires syconia (the closed Ficus inflorescence to complete its life cycle. Moreover, male gynodioecious fig species produces both pollen and pollen vectors, whereas the female counterpart produces only seeds. The recovery of the Mearns fig was observed to be rapid, with the production of both leaves and syconia. The syconium:leaf ratio was greater for male trees than for female trees, indicating the importance of syconium production for the wasp survival. Pollinating wasps live for approximately 1 day; therefore, receptive syconia are crucial. Every typhoon season, few typhoons pass by the coasts where the Mearns fig grows, destroying all the leaves and syconia. In this paper, we highlight the potential diminution of the fig population that can lead to the extinction of the mutualistic pair of species. The effects of climate change on coastal species warrant wider surveys.

  12. Effects of climate change on a mutualistic coastal species: Recovery from typhoon damages and risks of population erosion.

    Science.gov (United States)

    Chiu, Yu-Ting; Bain, Anthony; Deng, Shu-Lin; Ho, Yi-Chiao; Chen, Wen-Hsuan; Tzeng, Hsy-Yu

    2017-01-01

    Presently, climate change has increased the frequency of extreme meteorological events such as tropical cyclones. In the western Pacific basin, these cyclones are called typhoons, and in this area, around Taiwan Island, their frequency has almost doubled since 2000. When approaching landmasses, typhoons have devastating effects on coastal vegetation. The increased frequency of these events has challenged the survival of coastal plant species and their posttyphoon recovery. In this study, a population of coastal gynodioecious Ficus pedunculosa var. mearnsii (Mearns fig) was surveyed for two years to investigate its recovery after Typhoon Morakot, which occurred in August 2009. Similar to all the Ficus species, the Mearns fig has an obligate mutualistic association with pollinating fig wasp species, which requires syconia (the closed Ficus inflorescence) to complete its life cycle. Moreover, male gynodioecious fig species produces both pollen and pollen vectors, whereas the female counterpart produces only seeds. The recovery of the Mearns fig was observed to be rapid, with the production of both leaves and syconia. The syconium:leaf ratio was greater for male trees than for female trees, indicating the importance of syconium production for the wasp survival. Pollinating wasps live for approximately 1 day; therefore, receptive syconia are crucial. Every typhoon season, few typhoons pass by the coasts where the Mearns fig grows, destroying all the leaves and syconia. In this paper, we highlight the potential diminution of the fig population that can lead to the extinction of the mutualistic pair of species. The effects of climate change on coastal species warrant wider surveys.

  13. Population and biological parameters of selected fish species from the middle Xingu River, Amazon Basin.

    Science.gov (United States)

    Camargo, M; Giarrizzo, T; Isaac, V J

    2015-08-01

    This study estimates the main biological parameters, including growth rates, asymptotic length, mortality, consumption by biomass, biological yield, and biomass, for the most abundant fish species found on the middle Xingu River, prior to the construction of the Belo Monte Dam. The specimens collected in experimental catches were analysed with empirical equations and length-based FISAT methods. For the 63 fish species studied, high growth rates (K) and high natural mortality (M) were related to early sexual maturation and low longevity. The predominance of species with short life cycles and a reduced number of age classes, determines high rates of stock turnover, which indicates high productivity for fisheries, and a low risk of overfishing.

  14. Predator-induced synchrony in population oscillations of coexisting small mammal species

    OpenAIRE

    Korpimäki, Erkki; Norrdahl, Kai; Huitu, Otso; Klemola, Tero

    2005-01-01

    Comprehensive analyses of long-term (1977–2003) small-mammal abundance data from western Finland showed that populations of Microtus voles (field voles M. agrestis and sibling voles M. rossiaemeridionalis) voles, bank (Clethrionomys glareolus) and common shrews (Sorex araneus) fluctuated synchronously in 3 year population cycles. Time-series analyses indicated that interspecific synchrony is influenced strongly by density-dependent processes. Synchrony among Microtus and bank voles appeared a...

  15. Species distribution and physiological characterization of Acinetobacter genospecies from healthy human skin of tribal population in India

    Directory of Open Access Journals (Sweden)

    Yavankar S

    2007-01-01

    Full Text Available Background: Various reports on distribution of Acinetobacter spp. from healthy human skin restricted to urban population. However, no such data is available from healthy human skin of tribal population not exposed to modern antibiotics during their life time. Purpose: Isolation, biotyping, distribution and physiological characterisation of Acinetobacter spp. from healthy human skin of tribal population. Methods: Tribal population of Toranmal area of Satpuda Ranges, Maharashtra, India were sampled for ten body sites. Tentative Acinetobacter isolates were confirmed to the genus level by chromosomal DNA transformation assay and to species level using Bouvet and Grimont system. Novel physiological characteristics like pH, temperature and salt tolerance were studied. All strains were screened for production of various enzymes. Results: One hundred and eighteen strains were isolated, which belonged to nine Acinetobacter genospecies. A. haemolyticus was most abundant followed by A. calcoaceticus and A. genospecies 1-3. Higher percentage of Acinetobacter was recovered from skin of nose, Pawara tribe and female volunteers. They showed wide variation in temperature, salt and pH tolerance. Most of the strains could produce enzymes viz, lipase, esterase, urease and amylase. Conclusions: Acinetobacter spp. belonging to nine genospecies were obtained in the present study. Physiological characteristics including high salt, temperature and acidic pH tolerance were helpful to differentiate between the commensal and pathogenic species of Acinetobacter genus.

  16. Analysis of multiple tsetse fly populations in Uganda reveals limited diversity and species-specific gut microbiota.

    Science.gov (United States)

    Aksoy, Emre; Telleria, Erich L; Echodu, Richard; Wu, Yineng; Okedi, Loyce M; Weiss, Brian L; Aksoy, Serap; Caccone, Adalgisa

    2014-07-01

    The invertebrate microbiome contributes to multiple aspects of host physiology, including nutrient supplementation and immune maturation processes. We identified and compared gut microbial abundance and diversity in natural tsetse flies from Uganda using five genetically distinct populations of Glossina fuscipes fuscipes and multiple tsetse species (Glossina morsitans morsitans, G. f. fuscipes, and Glossina pallidipes) that occur in sympatry in one location. We used multiple approaches, including deep sequencing of the V4 hypervariable region of the 16S rRNA gene, 16S rRNA gene clone libraries, and bacterium-specific quantitative PCR (qPCR), to investigate the levels and patterns of gut microbial diversity from a total of 151 individuals. Our results show extremely limited diversity in field flies of different tsetse species. The obligate endosymbiont Wigglesworthia dominated all samples (>99%), but we also observed wide prevalence of low-density Sodalis (tsetse's commensal endosymbiont) infections (microbiota composition among the genetically distinct G. f. fuscipes flies and between different sympatric species. Interestingly, Wigglesworthia density varied in different species (10(4) to 10(6) normalized genomes), with G. f. fuscipes having the highest levels. We describe the factors that may be responsible for the reduced diversity of tsetse's gut microbiota compared to those of other insects. Additionally, we discuss the implications of Wigglesworthia and Sodalis density variations as they relate to trypanosome transmission dynamics and vector competence variations associated with different tsetse species. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  17. How will species respond to climate change? Examining the effects of temperature and population density on an herbivorous insect.

    Science.gov (United States)

    Laws, Angela Nardoni; Belovsky, Gary E

    2010-04-01

    An important challenge facing ecologists is to understand how climate change may affect species performance and species interactions. However, predicting how changes in abiotic variables associated with climate change may affect species performance also depends on the biotic context, which can mediate species responses to climatic change. We conducted a 3-yr field experiment to determine how the herbivorous grasshopper Camnula pellucida (Scudder) responds to manipulations of temperature and population density. Grasshopper survival and fecundity decreased with density, indicating the importance of intraspecific competition. Female fecundity tended to increase with temperature, whereas grasshopper survival exhibited a unimodal response to temperature, with highest survival at intermediate temperatures. Grasshopper performance responses to temperature also depended on density. Peak survival in the low-density treatment occurred in warmer conditions than for the high-density treatment, indicating that the intensity of intraspecific competition varies with temperature. Our data show that changes to the temperature regimen can alter grasshopper performance and determine the intensity of intraspecific competition. However, the effects of temperature on grasshopper performance varied with density. Our data indicate the importance of the biotic context in mediating species responses to climatic factors associated with global change.

  18. Zinc and cadmium accumulation among and within populations of the pseudometalophytic species Arrhenatherum elatius: Implications for phytoextraction

    Energy Technology Data Exchange (ETDEWEB)

    Deram, A. [Universite Droit et Sante de Lille - EA 2690, Institut Lillois d' Ingenierie de la Sante, 42, rue Ambroise Pare 59 120 Loos (France)]. E-mail: annabelle.deram@univ-lille2.fr; Denayer, F.-O. [Universite Droit et Sante de Lille - EA 2690, Institut Lillois d' Ingenierie de la Sante, 42, rue Ambroise Pare 59 120 Loos (France); Dubourgier, H.-C. [Eesti Maauelikool, Pollumajandus-ja keskkonnainstituut, Kreutzwaldi 64, Tartu 51 014 (Estonia); Douay, F. [Institut Superieur d' Agriculture, Laboratoire Sols et Environnement, 48, Boulevard Vauban 59 046 Lille (France); Petit, D. [Laboratoire de Genetique et Evolutions des Populations Vegetales, UPRESA-CNRS 8016, Bat SN2, Universite des Sciences et Technologies de Lille, Villeneuve d' Ascq, 59 655 France (France); Van Haluwyn, C. [Universite Droit et Sante de Lille - EA 2690, Departement de Botanique, Faculte des Sciences Pharmaceutiques et Biologiques, 3, rue du Professeur Laguesse, B.P. 83, F-59 006 Lille cedex (France)

    2007-01-01

    The purpose of this study was to investigate, under standard conditions, the bioaccumulation of zinc and cadmium in Arrhenatherum elatius, a perennial grass with a high biomass production. Nine populations of three different origins were tested: three metallicolous populations (mpop); three non-metallicolous populations (nmpop) and three populations developing on soils moderately metal polluted (medpop). We have found that bioaccumulation differs among these populations, with nmpop accumulating significantly more zinc (p < 0.0001) and cadmium (p < 0.0001) than mpop. Indeed, we have observed a concentration of 325 mg kg{sup -1} of zinc and 52 mg kg{sup -1} of cadmium in A. elatius shoots from mpop, whereas in nmpop, the concentration reached on average 524 mg kg{sup -1} zinc and 83 mg kg{sup -1} cadmium. In the same way, medpop accumulated as much zinc but more cadmium than nmpop. Moreover, the standard deviation of medpop was larger than the one for mpop and nmpop. Indeed, some A. elatius samples from medpop presented a high metal content whereas, others presented low concentrations in their shoots (ranging from 60 to 210 mg kg{sup -1} cadmium). Hence, these medpop exhibited a large variability among and within populations in accumulating zinc and cadmium in their shoots. Based on these results, the possibility of selecting A. elatius plants with the best accumulating capacity from medpop was proposed. We concluded that if the accumulation capacity is genetically controlled in A. elatius, this species fulfils this necessary condition for efficiently increasing species bioaccumulation by crossbreeding A. elatius plants with the higher accumulation capacity.

  19. Phenotypic variation of F1 and F2 populations from three species of ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-07-18

    Jul 18, 2008 ... tures which confer a competitive advantage over other common angiosperm species (Cipollini et al., 2002), generally regarded as weeds (Gbile, 1979). The genus provides enormous food resources as vege- tables and tubers (Omidiji, 1982) and medicinal source of unique alkaloids and other biochemical ...

  20. Parasite diversity and microsatellite variability in native and introduced populations of four Neogobius species (Gobiidae)

    Czech Academy of Sciences Publication Activity Database

    Ondračková, Markéta; Šimková, A.; Civáňová, K.; Vyskočilová, M.; Jurajda, Pavel

    2012-01-01

    Roč. 139, č. 11 (2012), s. 1493-1505 ISSN 0031-1820 R&D Projects: GA ČR(CZ) GAP505/11/1768 Institutional support: RVO:68081766 Keywords : goby * metazoan parasites * microsatellites * similarity * species introductions Subject RIV: EG - Zoology Impact factor: 2.355, year: 2012

  1. Population biology of two rare fern species: long-life and long-lasting stability

    Czech Academy of Sciences Publication Activity Database

    Bucharová, Anna; Münzbergová, Z.; Tájek, P.

    2010-01-01

    Roč. 97, č. 8 (2010), s. 1260-1271 ISSN 0002-9122 R&D Projects: GA MŽP SP/2D4/112/08 Institutional research plan: CEZ:AV0Z60050516 Keywords : ferns * life cycle * naturally rare species Subject RIV: EF - Botanics Impact factor: 3.052, year: 2010

  2. Co-Flocculation of Yeast Species, a New Mechanism to Govern Population Dynamics in Microbial Ecosystems

    Science.gov (United States)

    Rossouw, Debra; Bagheri, Bahareh; Setati, Mathabatha Evodia; Bauer, Florian Franz

    2015-01-01

    Flocculation has primarily been studied as an important technological property of Saccharomyces cerevisiae yeast strains in fermentation processes such as brewing and winemaking. These studies have led to the identification of a group of closely related genes, referred to as the FLO gene family, which controls the flocculation phenotype. All naturally occurring S. cerevisiae strains assessed thus far possess at least four independent copies of structurally similar FLO genes, namely FLO1, FLO5, FLO9 and FLO10. The genes appear to differ primarily by the degree of flocculation induced by their expression. However, the reason for the existence of a large family of very similar genes, all involved in the same phenotype, has remained unclear. In natural ecosystems, and in wine production, S. cerevisiae growth together and competes with a large number of other Saccharomyces and many more non-Saccharomyces yeast species. Our data show that many strains of such wine-related non-Saccharomyces species, some of which have recently attracted significant biotechnological interest as they contribute positively to fermentation and wine character, were able to flocculate efficiently. The data also show that both flocculent and non-flocculent S. cerevisiae strains formed mixed species flocs (a process hereafter referred to as co-flocculation) with some of these non-Saccharomyces yeasts. This ability of yeast strains to impact flocculation behaviour of other species in mixed inocula has not been described previously. Further investigation into the genetic regulation of co-flocculation revealed that different FLO genes impact differently on such adhesion phenotypes, favouring adhesion with some species while excluding other species from such mixed flocs. The data therefore strongly suggest that FLO genes govern the selective association of S. cerevisiae with specific species of non-Saccharomyces yeasts, and may therefore be drivers of ecosystem organisational patterns. Our data

  3. Flow cytometric characterization of peripheral blood leukocyte populations of 3 neotropical snake species: Boa constrictor, Bothrops jararaca, and Crotalus durissus.

    Science.gov (United States)

    Carvalho, Marcelo P N; Queiroz-Hazarbassanov, Nicolle G T; Massoco, Cristina O; Rossi, Silmara; Sant'Anna, Sávio S; Catão-Dias, José L; Grego, Kathleen F

    2016-06-01

    The reptilian immune system is represented by innate, humoral, and cell-mediated mechanisms, involving different types of blood leukocytes. The development of optimized methods for the advanced study of origin and function of reptilian blood leukocytes is needed. The purpose of the study was to optimize leukocyte density gradient isolation protocols from snake peripheral blood samples, and characterize recovered cells by flow cytometry based on size and internal complexity for a qualitative and semi-quantitative assessment of leukocyte populations in one boa (Boa constrictor), and 2 viper species (Bothrops jararaca, Crotalus durissus). Blood samples from 30 snakes (10 from each species, 5 males and 5 females) were collected in tubes with sodium heparin. Fresh blood was centrifuged with either ficoll-paque PLUS or percoll density gradients for leukocyte isolation. Flow cytometric leukocyte gates were defined based on size (forward scatter [FSC]) and internal complexity (side scatter [SSC]). Relative leukocyte differential counts after sorting the cells in these gates in one snake for each species were compared to conventional light microscopic differential counts on unsorted isolated leukocytes. There was no statistical difference in the relative leukocyte populations, including heterophils, azurophils, and small and large lymphocytes between samples isolated by ficoll or percoll. Four leukocyte gates were identified based on their location in FSC/SSC cytograms. The relative leukocyte differential counts after sorting in single animals showed some agreement with the light microscopy differential count on unsorted cells. Based on FSC and SSC, 4 distinct leukocyte populations were found in ficoll or percoll density gradient isolated leukocytes from peripheral blood from boa and viper species. Further optimization of the technique should allow the performance of functional assays. © 2016 American Society for Veterinary Clinical Pathology.

  4. Spatial structuring of the population genetics of a European subterranean termite species

    Science.gov (United States)

    Bankhead-Dronnet, Stéphanie; Perdereau, Elfie; Kutnik, Magdalena; Dupont, Simon; Bagnères, Anne-Geneviève

    2015-01-01

    In population genetics studies, detecting and quantifying the distribution of genetic variation can help elucidate ecological and evolutionary processes. In social insects, the distribution of population-level genetic variability is generally linked to colony-level genetic structure. It is thus especially crucial to conduct complementary analyses on such organisms to examine how spatial and social constraints interact to shape patterns of intraspecific diversity. In this study, we sequenced the mitochondrial COII gene for 52 colonies of the subterranean termite Reticulitermes grassei (Isoptera: Rhinotermitidae), sampled from a population in southwestern France. Three haplotypes were detected, one of which was found exclusively in the southern part of the study area (near the Pyrenees). After genotyping 6 microsatellite loci for 512 individual termites, we detected a significant degree of isolation by distance among individuals over the entire range; however, the cline of genetic differentiation was not continuous, suggesting the existence of differentiated populations. A spatial principal component analysis based on allele frequency data revealed significant spatial autocorrelation among genotypes: the northern and southern groups were strongly differentiated. This finding was corroborated by clustering analyses; depending on the randomized data set, two or three clusters, exhibiting significant degrees of differentiation, were identified. An examination of colony breeding systems showed that colonies containing related neotenic reproductives were prevalent, suggesting that inbreeding may contribute to the high level of homozygosity observed and thus enhance genetic contrasts among colonies. We discuss the effect of evolutionary and environmental factors as well as reproductive and dispersal modes on population genetic structure. PMID:26357538

  5. Population Dynamics Among six Major Groups of the Oryza rufipogon Species Complex, Wild Relative of Cultivated Asian Rice.

    Science.gov (United States)

    Kim, HyunJung; Jung, Janelle; Singh, Namrata; Greenberg, Anthony; Doyle, Jeff J; Tyagi, Wricha; Chung, Jong-Wook; Kimball, Jennifer; Hamilton, Ruaraidh Sackville; McCouch, Susan R

    2016-12-01

    Understanding population structure of the wild progenitor of Asian cultivated rice (O. sativa), the Oryza rufipogon species complex (ORSC), is of interest to plant breeders and contributes to our understanding of rice domestication. A collection of 286 diverse ORSC accessions was evaluated for nuclear variation using genotyping-by-sequencing (113,739 SNPs) and for chloroplast variation using Sanger sequencing (25 polymorphic sites). Six wild subpopulations were identified, with 25 % of accessions classified as admixed. Three of the wild groups were genetically and geographically closely related to the O. sativa subpopulations, indica, aus and japonica, and carried O. sativa introgressions; the other three wild groups were genetically divergent, had unique chloroplast haplotypes, and were located at the geographical extremes of the species range. The genetic subpopulations were significantly correlated (r 2  = 0.562) with traditional species designations, O. rufipogon (perennial) and O. nivara (annual), differentiated based on morphology and life history. A wild diversity panel of 95 purified (inbred) accessions was developed for future genetic studies. Our results suggest that the cultivated aus subpopulation is most closely related to an annual wild relative, japonica to a perennial wild relative, and indica to an admixed population of diverse annual and perennial wild ancestors. Gene flow between ORSC and O. sativa is common in regions where rice is cultivated, threatening the identity and diversity of wild ORSC populations. The three geographically isolated ORSC populations harbor variation rarely seen in cultivated rice and provide a unique window into the genetic composition of ancient rice subpopulations.

  6. Detection and characterization of Wolbachia infections in laboratory and natural populations of different species of tsetse flies (genus Glossina

    Directory of Open Access Journals (Sweden)

    Doudoumis Vangelis

    2012-01-01

    Full Text Available Abstract Background Wolbachia is a genus of endosymbiotic α-Proteobacteria infecting a wide range of arthropods and filarial nematodes. Wolbachia is able to induce reproductive abnormalities such as cytoplasmic incompatibility (CI, thelytokous parthenogenesis, feminization and male killing, thus affecting biology, ecology and evolution of its hosts. The bacterial group has prompted research regarding its potential for the control of agricultural and medical disease vectors, including Glossina spp., which transmits African trypanosomes, the causative agents of sleeping sickness in humans and nagana in animals. Results In the present study, we employed a Wolbachia specific 16S rRNA PCR assay to investigate the presence of Wolbachia in six different laboratory stocks as well as in natural populations of nine different Glossina species originating from 10 African countries. Wolbachia was prevalent in Glossina morsitans morsitans, G. morsitans centralis and G. austeni populations. It was also detected in G. brevipalpis, and, for the first time, in G. pallidipes and G. palpalis gambiensis. On the other hand, Wolbachia was not found in G. p. palpalis, G. fuscipes fuscipes and G. tachinoides. Wolbachia infections of different laboratory and natural populations of Glossina species were characterized using 16S rRNA, the wsp (Wolbachia Surface Protein gene and MLST (Multi Locus Sequence Typing gene markers. This analysis led to the detection of horizontal gene transfer events, in which Wobachia genes were inserted into the tsetse flies fly nuclear genome. Conclusions Wolbachia infections were detected in both laboratory and natural populations of several different Glossina species. The characterization of these Wolbachia strains promises to lead to a deeper insight in tsetse flies-Wolbachia interactions, which is essential for the development and use of Wolbachia-based biological control methods.

  7. Identification of the population density of a species model with nonlocal diffusion and nonlinear reaction

    Science.gov (United States)

    Tuan, Nguyen Huy; Van Au, Vo; Khoa, Vo Anh; Lesnic, Daniel

    2017-05-01

    The identification of the population density of a logistic equation backwards in time associated with nonlocal diffusion and nonlinear reaction, motivated by biology and ecology fields, is investigated. The diffusion depends on an integral average of the population density whilst the reaction term is a global or local Lipschitz function of the population density. After discussing the ill-posedness of the problem, we apply the quasi-reversibility method to construct stable approximation problems. It is shown that the regularized solutions stemming from such method not only depend continuously on the final data, but also strongly converge to the exact solution in L 2-norm. New error estimates together with stability results are obtained. Furthermore, numerical examples are provided to illustrate the theoretical results.

  8. Reproductive biology of Magnolia sinica (Magnoliaecea, a threatened species with extremely small populations in Yunnan, China

    Directory of Open Access Journals (Sweden)

    Ye Chen

    2016-10-01

    M. sinica is a self-compatible, pollinator-dependent species, and its fruit/seed set can be significantly increased by hand-pollination. No functional seed dispersers have been found in its extant natural habitats. These findings suggest that it may face both pollination and seed disperser insufficiencies in its current fragmented habitats, which may account for its low regeneration. Here we propose conservation strategies based on our findings.

  9. Unravelling population genetic structure with mitochondrial DNA in a notional panmictic coastal crab species: sample size makes the difference.

    Science.gov (United States)

    Fratini, Sara; Ragionieri, Lapo; Deli, Temim; Harrer, Alexandra; Marino, Ilaria A M; Cannicci, Stefano; Zane, Lorenzo; Schubart, Christoph D

    2016-07-26

    The extent of genetic structure of a species is determined by the amount of current gene flow and the impact of historical and demographic factors. Most marine invertebrates have planktonic larvae and consequently wide potential dispersal, so that genetic uniformity should be common. However, phylogeographic investigations reveal that panmixia is rare in the marine realm. Phylogeographic patterns commonly coincide with geographic transitions acting as barriers to gene flow. In the Mediterranean Sea and adjoining areas, the best known barriers are the Atlantic-Mediterranean transition, the Siculo-Tunisian Strait and the boundary between Aegean and Black seas. Here, we perform the so far broadest phylogeographic analysis of the crab Pachygrapsus marmoratus, common across the north-eastern Atlantic Ocean, Mediterranean and Black seas. Previous studies revealed no or weak genetic structuring at meso-geographic scale based on mtDNA, while genetic heterogeneity at local scale was recorded with microsatellites, even if without clear geographic patterns. Continuing the search for phylogeographic signal, we here enlarge the mtDNA dataset including 51 populations and covering most of the species' distribution range. This enlarged dataset provides new evidence of three genetically separable groups, corresponding to the Portuguese Atlantic Ocean, Mediterranean Sea plus Canary Islands, and Black Sea. Surprisingly, hierarchical AMOVA and Principal Coordinates Analysis agree that our Canary Islands population is closer to western Mediterranean populations than to mainland Portugal and Azores populations. Within the Mediterranean Sea, we record genetic homogeneity, suggesting that population connectivity is unaffected by the transition between the western and eastern Mediterranean. The Mediterranean metapopulation seems to have experienced a relatively recent expansion around 100,000 years ago. Our results suggest that the phylogeographic pattern of P. marmoratus is shaped by the

  10. Alterations in Fecal Lactobacillus and Bifidobacterium Species in Type 2 Diabetic Patients in Southern China Population

    Directory of Open Access Journals (Sweden)

    Kim-Anne eLê

    2013-01-01

    Full Text Available Background: The connection between gut microbiota and metabolism and its role in the pathogenesis of diabetes are increasingly recognized. The objective of this study was to quantitatively measure Bifidobacterium and Lactobacillus species, members of commensal bacteria found in human gut, in type 2 diabetic patients (T2D patients from Southern China. Methods: Fifty patients with T2D and thirty control individuals of similar BMI were recruited from Southern China. T2D and control subjects were confirmed with both oral glucose tolerance test (OGTT and HbA1c measurements. Bifidobacterium and Lactobacillus species in feces were measured by real-time quantitative PCR. Data were analyzed with STATA 11.0 statistical software.Results: In comparison to control subjects T2D patients had significantly more total Lactobacillus (+18%, L. bugaricus (+13%, L. rhamnosum (+37% and L. acidophilus (+48% (P <0.05. In contrast, T2D patients had less amounts of total Bifidobacteria (-7% and B. adolescentis (-12% (P <0.05. Cluster analysis showed that gut microbiota pattern of T2D patients is characterized by greater numbers of L. rhamnosus and L. acidophillus, together with lesser numbers of B. adolescentis (P <0.05. Conclusion: The gut microflora in T2D patients is characterized by greater numbers of Lactobacillus and lesser numbers of Bifidobacterium species.

  11. Population assessment of Acropora palmata (Scleractinia: Acroporidae: relationship between habitat and reef associated species

    Directory of Open Access Journals (Sweden)

    K. Martínez

    2014-09-01

    Full Text Available Three decades ago, Acropora palmata was one of the main reef-building coral species throughout the Caribbean, forming an essential component of the structural complexity of shallow coral reef habitats. These colonies still provide microhabitats for settlement, food and shelter to many vertebrates and invertebrates. The recent decline of A. palmata has been followed by a significant loss in spatial heterogeneity and possibly in species diversity. Studies addressing whether dead and living stands of Acropora hold different fish and benthic assemblages are scarce. The status of Acropora colonies and their associated species were assessed in October 2012, at two reef zones of Cayo Sombrero, Venezuela. Visual censuses of fish abundance and the number of macrofaunal individuals were recorded for both live and dead zones. Living Acropora colonies had the lowest abundance (˂31%. In both zoned the fish community was dominated by damselfishes (˂53% and wrasses (˂36%, the benthic macrofauna by peracarid crustaceans (˂40% and polychaetes (˂38%. Fish and benthic communities were not correlated with the condition (live or dead of the Acropora habitats; possibly branching structures provide the necessary shelter and protection no matter if they are dead or alive. More replication is necessary to test this unexpected result.

  12. Impact of environmental colored noise in single-species population dynamics

    Science.gov (United States)

    Spanio, Tommaso; Hidalgo, Jorge; Muñoz, Miguel A.

    2017-10-01

    Variability on external conditions has important consequences for the dynamics and the organization of biological systems. In many cases, the characteristic timescale of environmental changes as well as their correlations play a fundamental role in the way living systems adapt and respond to it. A proper mathematical approach to understand population dynamics, thus, requires approaches more refined than, e.g., simple white-noise approximations. To shed further light onto this problem, in this paper we propose a unifying framework based on different analytical and numerical tools available to deal with "colored" environmental noise. In particular, we employ a "unified colored noise approximation" to map the original problem into an effective one with white noise, and then we apply a standard path integral approach to gain analytical understanding. For the sake of specificity, we present our approach using as a guideline a variation of the contact process—which can also be seen as a birth-death process of the Malthus-Verhulst class—where the propagation or birth rate varies stochastically in time. Our approach allows us to tackle in a systematic manner some of the relevant questions concerning population dynamics under environmental variability, such as determining the stationary population density, establishing the conditions under which a population may become extinct, and estimating extinction times. We focus on the emerging phase diagram and its possible phase transitions, underlying how these are affected by the presence of environmental noise time-correlations.

  13. Population Development of Baltic Bird Species: Great Cormorant (Phalacrocorax carbo sinensis) - Update with results from 2011

    DEFF Research Database (Denmark)

    Herrmann, Christof; Bregnballe, Thomas; Larsson, Kjell

    2011-01-01

    During the 19th century, the Great Cormorant was exterminated as a breeding bird in several Baltic countries. The persecution continued until the mid of the 20th century, and in the early 1960s the European breeding population of the continental subspecies sinensis had declined to 4 000 breeding...

  14. Population divergence in the ontogenetic trajectories of foliar terpenes of a Eucalyptus species

    Science.gov (United States)

    Borzak, Christina L.; Potts, Brad M.; Davies, Noel W.; O’Reilly-Wapstra, Julianne M.

    2015-01-01

    Background and Aims The development of plant secondary metabolites during early life stages can have significant ecological and evolutionary implications for plant–herbivore interactions. Foliar terpenes influence a broad range of ecological interactions, including plant defence, and their expression may be influenced by ontogenetic and genetic factors. This study investigates the role of these factors in the expression of foliar terpene compounds in Eucalyptus globulus seedlings. Methods Seedlings were sourced from ten families each from three genetically distinct populations, representing relatively high and low chemical resistance to mammalian herbivory. Cotyledon-stage seedlings and consecutive leaf pairs of true leaves were harvested separately across an 8-month period, and analysed for eight monoterpene compounds and six sesquiterpene compounds. Key Results Foliar terpenes showed a series of dynamic changes with ontogenetic trajectories differing between populations and families, as well as between and within the two major terpene classes. Sesquiterpenes changed rapidly through ontogeny and expressed opposing trajectories between compounds, but showed consistency in pattern between populations. Conversely, changed expression in monoterpene trajectories was population- and compound-specific. Conclusions The results suggest that adaptive opportunities exist for changing levels of terpene content through ontogeny, and evolution may exploit the ontogenetic patterns of change in these compounds to create a diverse ontogenetic chemical mosaic with which to defend the plant. It is hypothesized that the observed genetically based patterns in terpene ontogenetic trajectories reflect multiple changes in the regulation of genes throughout different terpene biosynthetic pathways. PMID:25434028

  15. How do population genetic parameters affect germination of the heterocarpic species Atriplex tatarica (Amaranthaceae)?

    Czech Academy of Sciences Publication Activity Database

    Kochánková, J.; Mandák, Bohumil

    2009-01-01

    Roč. 103, č. 8 (2009), s. 1303-1313 ISSN 0305-7364 R&D Projects: GA AV ČR IAA600050707 Institutional research plan: CEZ:AV0Z60050516 Keywords : imbreeding depression * population genetics * seed dimorphism Subject RIV: EF - Botanics Impact factor: 3.501, year: 2009

  16. Influence of weather factors on population dynamics of two lagomorph species based on hunting bag records

    NARCIS (Netherlands)

    Rödel, H.; Dekker, J.J.A.

    2012-01-01

    Weather conditions can have a significant influence on short-term fluctuations of animal populations. In our study, which is based on time series of hunting bag records of up to 28 years from 26 counties of The Netherlands and Germany, we investigated the impact of different weather variables on

  17. 78 FR 79622 - Endangered and Threatened Species: Designation of a Nonessential Experimental Population of...

    Science.gov (United States)

    2013-12-31

    ... identifying fish that are reintroduced, such as marking fish with specific fin clips (e.g., coded-wire tags... population area that have intact adipose fins as well as those that are adipose fin-clipped. In addition, the... thereby impact water supply. NMFS will develop a technical memorandum (tech memo) annually containing a...

  18. Disease associated population effects of commercial fish and shellfish species (ToR g)

    DEFF Research Database (Denmark)

    Lang, T.; Alfjorden, A.; Feist, S.W.

    2015-01-01

    Pathogens are increasingly reported from populations of aquatic animals. Variations in the frequency and abundance of pathogens depend on spatial or temporal factors as well as those related to host effects such as age or condition. Similarly, the devel-opment of a disease is a function of the co...

  19. Differences in Fusarium Species in brown midrib Sorghum and in Air Populations in Production Fields.

    Science.gov (United States)

    Funnell-Harris, Deanna L; Scully, Erin D; Sattler, Scott E; French, Roy C; O'Neill, Patrick M; Pedersen, Jeffrey F

    2017-11-01

    Several Fusarium spp. cause sorghum (Sorghum bicolor) grain mold, resulting in deterioration and mycotoxin production in the field and during storage. Fungal isolates from the air (2005 to 2006) and from leaves and grain from wild-type and brown midrib (bmr)-6 and bmr12 plants (2002 to 2003) were collected from two locations. Compared with the wild type, bmr plants have reduced lignin content, altered cell wall composition, and different levels of phenolic intermediates. Multilocus maximum-likelihood analysis identified two Fusarium thapsinum operational taxonomic units (OTU). One was identified at greater frequency in grain and leaves of bmr and wild-type plants but was infrequently detected in air. Nine F. graminearum OTU were identified: one was detected at low levels in grain and leaves while the rest were only detected in air. Wright's F statistic (F ST ) indicated that Fusarium air populations differentiated between locations during crop anthesis but did not differ during vegetative growth, grain development, and maturity. F ST also indicated that Fusarium populations from wild-type grain were differentiated from those in bmr6 or bmr12 grain at one location but, at the second location, populations from wild-type and bmr6 grain were more similar. Thus, impairing monolignol biosynthesis substantially effected Fusarium populations but environment had a strong influence.

  20. 78 FR 66139 - Endangered and Threatened Species; Delisting of the Eastern Distinct Population Segment of...

    Science.gov (United States)

    2013-11-04

    ... the listing status of the western DPS to endangered, and keep the eastern DPS listed as threatened. In... the basic trend of this DPS, we briefly explain below the way in which population abundance is...; identify data available on which to evaluate trends in abundance; and summarize the information available...

  1. 75 FR 12597 - Endangered and Threatened Species; Proposed Listing of Nine Distinct Population Segments of...

    Science.gov (United States)

    2010-03-16

    ... numbers only in Brazil. In the eastern Atlantic, the largest nesting population of loggerheads is in the... beaches in Brazil. Recaptures of tagged juvenile turtles and nesting females have shown movement of... in Cyprus migrate to Egypt and Libya, exhibiting fidelity in following the same migration route...

  2. The population structure of wild sorghum species in agro-ecological ...

    African Journals Online (AJOL)

    There is need to understand the genetic structure of wild sorghums that grow alongside cultivated traditional sorghum varieties in order to assess the potential effect of crop genes in wild populations. In this study, 175 wild sorghum samples were collected from 13 agroecological zones (AEZs) from three counties in Western ...

  3. Population structure and demographic history of a tropical lowland rainforest tree species Shorea parvifolia (Dipterocarpaceae) from Southeastern Asia

    Science.gov (United States)

    Iwanaga, Hiroko; Teshima, Kosuke M; Khatab, Ismael A; Inomata, Nobuyuki; Finkeldey, Reiner; Siregar, Iskandar Z; Siregar, Ulfah J; Szmidt, Alfred E

    2012-01-01

    Distribution of tropical rainforests in Southeastern Asia has changed over geo-logical time scale, due to movement of tectonic plates and/or global climatic changes. Shorea parvifolia is one of the most common tropical lowland rainforest tree species in Southeastern Asia. To infer population structure and demographic history of S. parvifolia, as indicators of temporal changes in the distribution and extent of tropical rainforest in this region, we studied levels and patterns of nucleotide polymorphism in the following five nuclear gene regions: GapC, GBSSI, PgiC, SBE2, and SODH. Seven populations from peninsular Malaysia, Sumatra, and eastern Borneo were included in the analyses. STRUCTURE analysis revealed that the investigated populations are divided into two groups: Sumatra-Malay and Borneo. Furthermore, each group contained one admixed population. Under isolation with migration model, divergence of the two groups was estimated to occur between late Pliocene (2.6 MYA) and middle Pleistocene (0.7 MYA). The log-likelihood ratio tests of several demographic models strongly supported model with population expansion and low level of migration after divergence of the Sumatra-Malay and Borneo groups. The inferred demographic history of S. parvifolia suggested the presence of a scarcely forested land bridge on the Sunda Shelf during glacial periods in the Pleistocene and predominance of tropical lowland rainforest at least in Sumatra and eastern Borneo. PMID:22957170

  4. Differentiation of epipactis palustris (l.) crantz (orchidaceae) in habitats altered by man based on species populations within poznan city (poland)

    International Nuclear Information System (INIS)

    Wieloch, M.K.; Raszewska, M.W.; Drapikowska, M.

    2017-01-01

    The aim of the study was to compare two populations of Epipactis palustris (Orchidaceae) growing in the valley of Junikowski Stream, in the south-western part of the Poznan city (square of ATPOL BD08) and to compare current results to data on the species described in the literature. Group characteristics of both populations, such as population size, average density and congestion factor, as well as the average coefficient of dispersion, were defined. Specimen variability was determined by measuring 250 generative ramets in each population. The following plant traits were included: stem length, inflorescence length, number of flowers per inflorescence, number of leaves per stem and length and width of the largest leaf. Obtained data were subjected to statistical analyses. Descriptive statistics were calculated (arithmetic average, standard deviation, minimum and maximum). The variation coefficient (V) was established to determine the variation degree of each trait. In order to determine statistical significance of average values of traits of the samples in question, the factor variance ANOVA F-statistics was used. The significance degree was examined with Scheffe's test. Principal component analysis (PCA) enabled the examination of mutual relations between the samples in the system of two first principal components. This work confirmed previous information about low variability of marsh helleborine. Individual traits in both populations were very similar. The differences concerned the group characteristics. The plants were in good condition irrespective of occupied habitat. (author)

  5. A Distinctive and Host-Restricted Gut Microbiota in Populations of a Cactophilic Drosophila Species.

    Science.gov (United States)

    Martinson, Vincent G; Carpinteyro-Ponce, Javier; Moran, Nancy A; Markow, Therese A

    2017-12-01

    Almost all animals possess gut microbial communities, but the nature of these communities varies immensely. For example, in social bees and mammals, the composition is relatively constant within species and is dominated by specialist bacteria that do not live elsewhere; in laboratory studies and field surveys of Drosophila melanogaster , however, gut communities consist of bacteria that are ingested with food and that vary widely among individuals and localities. We addressed whether an ecological specialist in its natural habitat has a microbiota dominated by gut specialists or by environmental bacteria. Drosophila nigrospiracula is a species that is endemic to the Sonoran Desert and is restricted to decaying tissues of two giant columnar cacti, Pachycereus pringlei (cardón cactus) and Carnegiea gigantea (saguaro cactus). We found that the D. nigrospiracula microbiota differs strikingly from that of the cactus tissue on which the flies feed. The most abundant bacteria in the flies are rare or completely absent in the cactus tissue and are consistently abundant in flies from different cacti and localities. Several of these fly-associated bacterial groups, such as the bacterial order Orbales and the genera Serpens and Dysgonomonas , have been identified in prior surveys of insects from the orders Hymenoptera, Coleoptera, Lepidoptera, and Diptera, including several Drosophila species. Although the functions of these bacterial groups are mostly unexplored, Orbales species studied in bees are known to break down plant polysaccharides and use the resulting sugars. Thus, these bacterial groups appear to be specialized to the insect gut environment, where they may colonize through direct host-to-host transmission in natural settings. IMPORTANCE Flies in the genus Drosophila have become laboratory models for microbiota research, yet the bacteria commonly used in these experiments are rarely found in wild-caught flies and instead represent bacteria also present in the food

  6. Using species distribution model to estimate the wintering population size of the endangered scaly-sided merganser in China.

    Science.gov (United States)

    Zeng, Qing; Zhang, Yamian; Sun, Gongqi; Duo, Hairui; Wen, Li; Lei, Guangchun

    2015-01-01

    Scaly-sided Merganser is a globally endangered species restricted to eastern Asia. Estimating its population is difficult and considerable gap exists between populations at its breeding grounds and wintering sites. In this study, we built a species distribution model (SDM) using Maxent with presence-only data to predict the potential wintering habitat for Scaly-sided Merganser in China. Area under the receiver operating characteristic curve (AUC) method suggests high predictive power of the model (training and testing AUC were 0.97 and 0.96 respectively). The most significant environmental variables included annual mean temperature, mean temperature of coldest quarter, minimum temperature of coldest month and precipitation of driest quarter. Suitable conditions for Scaly-sided Merganser are predicted in the middle and lower reaches of the Yangtze River, especially in Jiangxi, Hunan and Hubei Provinces. The predicted suitable habitat embraces 6,984 km of river. Based on survey results from three consecutive winters (2010-2012) and previous studies, we estimated that the entire wintering population of Scaly-sided Merganser in China to be 3,561 ± 478 individuals, which is consistent with estimate in its breeding ground.

  7. Using species distribution model to estimate the wintering population size of the endangered scaly-sided merganser in China.

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    Qing Zeng

    Full Text Available Scaly-sided Merganser is a globally endangered species restricted to eastern Asia. Estimating its population is difficult and considerable gap exists between populations at its breeding grounds and wintering sites. In this study, we built a species distribution model (SDM using Maxent with presence-only data to predict the potential wintering habitat for Scaly-sided Merganser in China. Area under the receiver operating characteristic curve (AUC method suggests high predictive power of the model (training and testing AUC were 0.97 and 0.96 respectively. The most significant environmental variables included annual mean temperature, mean temperature of coldest quarter, minimum temperature of coldest month and precipitation of driest quarter. Suitable conditions for Scaly-sided Merganser are predicted in the middle and lower reaches of the Yangtze River, especially in Jiangxi, Hunan and Hubei Provinces. The predicted suitable habitat embraces 6,984 km of river. Based on survey results from three consecutive winters (2010-2012 and previous studies, we estimated that the entire wintering population of Scaly-sided Merganser in China to be 3,561 ± 478 individuals, which is consistent with estimate in its breeding ground.

  8. Application of molecular methods to demonstrate species and strain evolution of acetic acid bacteria population during wine production.

    Science.gov (United States)

    González, Angel; Hierro, Núria; Poblet, Montse; Mas, Albert; Guillamón, José Manuel

    2005-07-25

    The growth of acetic acid bacteria on grapes or throughout the winemaking process influences the quality of wine, mainly because it increases the volatile acidity. The objective of this study was to analyse how the acetic acid bacteria population evolves in the changing environment of the grape surface and during wine fermentation. We have analysed the influence of yeast inoculation and SO2 addition on acetic acid bacteria populations. These bacteria were analysed at both the species and the strain level by molecular methods such as Restriction Fragment Length Polimorfism (RFLP) of amplified 16S rDNA, and amplification by polymerase chain reaction of Enterobacterial Repetitive Intergenic Consensus (ERIC-PCR) and Repetitive Extragenic Palindromic (REP-PCR). Our results show that the increases in population size are normally accompanied by a proliferation of Acetobacter aceti, which is the main species during fermentation. The diversity of strains is considerable in natural environments such as the grape surface. Changes in the environment during alcoholic fermentation substantially reduce the survival and the diversity of acetic acid bacteria. Few strains are able to survive these conditions and they seem to originate from both the grapes and the winery. To the best of our knowledge this is the first time that acetic acid bacteria are analysed at the strain level in grape surfaces and during winemaking.

  9. The microgeographical patterns of morphological and molecular variation of a mixed ploidy population in the species complex Actinidia chinensis.

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    Yifei Liu

    Full Text Available Polyploidy and hybridization are thought to have significant impacts on both the evolution and diversification of the genus Actinidia, but the structure and patterns of morphology and molecular diversity relating to ploidy variation of wild Actinidia plants remain much less understood. Here, we examine the distribution of morphological variation and ploidy levels along geographic and environmental variables of a large mixed-ploidy population of the A. chinensis species complex. We then characterize the extent of both genetic and epigenetic diversity and differentiation exhibited between individuals of different ploidy levels. Our results showed that while there are three ploidy levels in this population, hexaploids were constituted the majority (70.3%. Individuals with different ploidy levels were microgeographically structured in relation to elevation and extent of niche disturbance. The morphological characters examined revealed clear difference between diploids and hexaploids, however tetraploids exhibited intermediate forms. Both genetic and epigenetic diversity were high but the differentiation among cytotypes was weak, suggesting extensive gene flow and/or shared ancestral variation occurred in this population even across ploidy levels. Epigenetic variation was clearly correlated with changes in altitudes, a trend of continuous genetic variation and gradual increase of epigenomic heterogeneities of individuals was also observed. Our results show that complex interactions between the locally microgeographical environment, ploidy and gene flow impact A. chinensis genetic and epigenetic variation. We posit that an increase in ploidy does not broaden the species habitat range, but rather permits A. chinensis adaptation to specific niches.

  10. Estimating trends of population decline in long-lived marine species in the Mediterranean Sea based on fishers' perceptions.

    Science.gov (United States)

    Maynou, Francesc; Sbrana, Mario; Sartor, Paolo; Maravelias, Christos; Kavadas, Stefanos; Damalas, Dimitros; Cartes, Joan E; Osio, Giacomo

    2011-01-01

    We conducted interviews of a representative sample of 106 retired fishers in Italy, Spain and Greece, asking specific questions about the trends they perceived in dolphin and shark abundances between 1940 and 1999 (in three 20 year periods) compared to the present abundance. The large marine fauna studied were not target species of the commercial fleet segment interviewed (trawl fishery). The fishers were asked to rank the perceived abundance in each period into qualitative ordinal classes based on two indicators: frequency of sightings and frequency of catches (incidental or intentional) of each taxonomic group. The statistical analysis of the survey results showed that both incidental catches and the sighting frequency of dolphins have decreased significantly over the 60+ years of the study period (except for in Greece due to the recent population increase). This shows that fishers' perceptions are in agreement with the declining population trends detected by scientists. Shark catches were also perceived to have diminished since the early 1940s for all species. Other long-lived Mediterranean marine fauna (monk seals, whales) were at very low levels in the second half of the 20(th) century and no quantitative data could be obtained. Our study supports the results obtained in the Mediterranean and other seas that show the rapid disappearance (over a few decades) of marine fauna. We show that appropriately designed questionnaires help provide a picture of animal abundance in the past through the valuable perceptions of fishers. This information can be used to complement scientific sources or in some cases be taken as the only information source for establishing population trends in the abundance of sensitive species.

  11. Relevance of risk predictions derived from a chronic species sensitivity distribution with cadmium to aquatic populations and ecosystems

    Science.gov (United States)

    Mebane, C.A.

    2010-01-01

    Criteria to protect aquatic life are intended to protect diverse ecosystems, but in practice are usually developed from compilations of single-species toxicity tests using standard test organisms that were tested in laboratory environments. Species sensitivity distributions (SSDs) developed from these compilations are extrapolated to set aquatic ecosystem criteria. The protectiveness of the approach was critically reviewed with a chronic SSD for cadmium comprising 27 species within 21 genera. Within the data set, one genus had lower cadmium effects concentrations than the SSD fifth percentile-based criterion, so in theory this genus, the amphipod Hyalella, could be lost or at least allowed some level of harm by this criteria approach. However, population matrix modeling projected only slightly increased extinction risks for a temperate Hyalella population under scenarios similar to the SSD fifth percentile criterion. The criterion value was further compared to cadmium effects concentrations in ecosystem experiments and field studies. Generally, few adverse effects were inferred from ecosystem experiments at concentrations less than the SSD fifth percentile criterion. Exceptions were behavioral impairments in simplified food web studies. No adverse effects were apparent in field studies under conditions that seldom exceeded the criterion. At concentrations greater than the SSD fifth percentile, the magnitudes of adverse effects in the field studies were roughly proportional to the laboratory-based fraction of species with adverse effects in the SSD. Overall, the modeling and field validation comparisons of the chronic criterion values generally supported the relevance and protectiveness of the SSD fifth percentile approach with cadmium. ?? 2009 Society for Risk Analysis.

  12. Evaluation of multi-species weed competition and weeds population dynamic in corn Zea mays L. field

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    S Mijani

    2016-05-01

    Full Text Available In order to examine the multi-species weed competition in corn field an experiment as an interval mapping was carried out at the Agricultural Research field of Ferdowsi University of Mashhad during growing season 2009-2010. At 3-4 leafy stages of corn, 20 non-destructive quadrates determine and the density of weeds was counted separately. At the same time, 20 destructive quadrates determine and in addition of counting number of plants, leaf area index and dry weight of each species were recorded separately. By using data from previous section, hyperbolic functions were fitted. In these functions number of species serve as the independent variable, weight or leaf area was considered as the dependent variable. With the help of these functions and leaf dry weight of each species was determined for non-destructive quadrates at this stage. Relative leaf area at early season as independent variables and natural logarithm of individual plant weight at later season as dependent variable in a multiple linear regression was fitted to obtain the interspecies competition coefficients. Based on ln of weight of single plant equation the weed interference effects on the corn yield can be divided into two groups: inhibition (negative sign and stimulation (positive sign. Among all weeds, night shade (Solanum nigrum L., redroot pigweed (Amaranthus retroflexus L. and lambsquarter (Chenopodium album L. had positive effects on corn yield, respectively. In fact, these weeds had competition and negative impacts on other weeds and reduced their competition power with corn and caused facilitation role on corn yield. At the end of growing season of corn, population of lambsquarter and Common purslane (Portulaca oleracea L. decreased while population of barnyard grass(Echinochloa crus-galli L., redroot pigweed and night shade increased.

  13. Population genetic structure of the major malaria vector Anopheles funestus s.s. and allied species in southern Africa

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    Choi Kwang Shik

    2012-12-01

    Full Text Available Abstract Background Anopheles funestus s.s., one of the major malaria vectors in sub-Saharan Africa, belongs to a group of eleven African species that are morphologically similar at the adult stage, most of which do not transmit malaria. The population structure of An. funestus based on mitochondrial DNA data led to the description of two cryptic subdivisions, clade I widespread throughout Africa and clade II known only from Mozambique and Madagascar. In this study, we investigated five common members of the Anopheles funestus group in southern Africa in order to determine relationships within and between species. Methods A total of 155 specimens of An. funestus, An. parensis, An. vaneedeni, An. funestus-like and An. rivulorum from South Africa, Mozambique and Malawi were used for the study. The population genetic structure was assessed within and between populations using mitochondrial DNA. Results The phylogenetic trees revealed three main lineages: 1 An. rivulorum; 2 An. funestus-like clade I and An. parensis clade II; and 3 An. funestus clades I and II, An. funestus-like clade II, An. parensis clade I and An. vaneedeni clades I and II. Within An. funestus, 32 specimens from Mozambique consisted of 40.6% clade I and 59.4% clade II while all 21 individuals from Malawi were clade I. In the analysis of mitochondrial DNA sequences, there were 37 polymorphic sites and 9 fixed different nucleotides for ND5 and 21 polymorphic sites and 6 fixed different nucleotides for COI between the two An. funestus clades. The results for COI supported the ND5 analysis. Conclusion This is the first report comparing An. funestus group species including An. funestus clades I and II and the new species An. funestus-like. Anopheles funestus clade I is separated from the rest of the members of the An. funestus subgroup and An. funestus-like is distinctly distributed from the other species in this study. However, there were two clades for An. funestus-like, An

  14. Population expansion of some bird species in the city of Wrocław

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    Kopij Grzegorz

    2016-12-01

    Full Text Available During the years 2002-2010, distribution and numbers of eight bird species were studied in the whole city of Wrocław, SW Poland (293 km2. The estimation for these species are as follow: Streptopelia turtur: 3 breeding pairs, Upupa epops: 1, Cuculus canorus: 49, Emberiza hortulana: 7, Luscinia megarhynchos: 214-286, Phoenicurus phoenicurus: 87-118, Turdus pilaris: 105-150, Hippolais icterina: 136-181. In comparison with 1980‘s and 1990’s, a rapid increase in the numbers P. phoenicurus, and T. pilaris, and a slight increase of L. megarhynchos and Cuculus canorus were documented. T. pilaris began to breed in the city in the end of 1990‘s. The increase may indicate that the habitats in Wrocław improved both in regard to food availability, nesting sites and other environmental requisitions. The increase in the numbers recorded for C. canorus, P. phoe-nicurus, and L. megarhynchos may also be a result of good conditions prevailing in their wintering grounds in sub-Saharan Africa.

  15. The role of natural radioresistance and ecological specialization of a specie in radio adaptation (as exemplified by natural rodent populations)

    Energy Technology Data Exchange (ETDEWEB)

    Grigorkina, E.; Olenev, G. [Institute of Plant and Animal Ecology, Ural Branch RAS, Ekaterinburg, (Russian Federation)

    2004-07-01

    The problem of mammal radio-adaptation is closely connected with problems of micro-evolution and prediction of the fate of irradiated populations. This report gives new materials on radio-adaptation of small mammals inhabiting the East Ural Radioactive Trace (EURT) which has been formed after the Kyshtym accident in 1957 year. The EURT zone is a unique area for studying long-term consequences of chronic low-dose irradiation of small mammal populations many generations being born after the accident. The role of natural radioresistance, ecological specialization and biological characteristics of a specie in the development of radio-adaptation are discussed. The objects of investigation were rodents: 1) Ellobius talpinus is a peculiar specialized specie with low ability to migrate, burrowing underground way of life and lifespan up to 6 years; 2) Sylvaemus uralensis, Apodemus agrarius, Clethrionomys rutilus widespread aboveground species, very active migrators with a 1.5 year lifespan. Significant differences were found among species in natural radioresistance to acute gamma-irradiation. LD{sub 50/30} is 5.0{+-}0.7 Gy for the Ellobius talpinus, 7.0{+-}0.4 Gy for the Sylvaemus uralensis, 10.0{+-}0.2 Gy for the Apodemus agrarius, 12.8{+-}0.2 Gy for the Clethrionomys rutilus. Despite the high radiosensitivity the Ellobius talpinus was more tolerant to chronic irradiation (over 45 years inhabiting the EURT, soil pollution by {sup 90}Sr was 950-1050 Ci/km{sup 2} - 35-39 MBq/m{sup 2}) in a complex of morpho-physiological, haematological and immunological parameters, than other species with active migration activity (the initial pollution of soil by {sup 90}Sr was 400-540 Ci/km{sup 2} - 15-20 MBq/m{sup 2}). This phenomenon is explained by radio-adaptation which developed in the Ellobius talpinus due to isolation of their settlement in the periphery of the area in conditions of radio-contamination. Various radioresistance to acute and chronic irradiation, disproportion of

  16. Global Population Structure of a Worldwide Pest and Virus Vector: Genetic Diversity and Population History of the Bemisia tabaci Sibling Species Group.

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    Margarita Hadjistylli

    Full Text Available The whitefly Bemisia tabaci sibling species (sibsp. group comprises morphologically indiscernible lineages of well-known exemplars referred to as biotypes. It is distributed throughout tropical and subtropical latitudes and includes the contemporary invasive haplotypes, termed B and Q. Several well-studied B. tabaci biotypes exhibit ecological and biological diversity, however, most members are poorly studied or completely uncharacterized. Genetic studies have revealed substantial diversity within the group based on a fragment of the mitochondrial cytochrome oxidase I (mtCOI sequence (haplotypes, with other tested markers being less useful for deep phylogenetic comparisons. The view of global relationships within the B. tabaci sibsp. group is largely derived from this single marker, making assessment of gene flow and genetic structure difficult at the population level. Here, the population structure was explored for B. tabaci in a global context using nuclear data from variable microsatellite markers. Worldwide collections were examined representing most of the available diversity, including known monophagous, polyphagous, invasive, and indigenous haplotypes. Well-characterized biotypes and other related geographic lineages discovered represented highly differentiated genetic clusters with little or no evidence of gene flow. The invasive B and Q biotypes exhibited moderate to high levels of genetic diversity, suggesting that they stemmed from large founding populations that have maintained ancestral variation, despite homogenizing effects, possibly due to human-mediated among-population gene flow. Results of the microsatellite analyses are in general agreement with published mtCOI phylogenies; however, notable conflicts exist between the nuclear and mitochondrial relationships, highlighting the need for a multifaceted approach to delineate the evolutionary history of the group. This study supports the hypothesis that the extant B. tabaci sibsp

  17. Prioritizing management actions for invasive populations using cost, efficacy, demography and expert opinion for 14 plant species world-wide.

    Science.gov (United States)

    Kerr, Natalie Z; Baxter, Peter W J; Salguero-Gómez, Roberto; Wardle, Glenda M; Buckley, Yvonne M

    2016-04-01

    Management of invasive populations is typically investigated case-by-case. Comparative approaches have been applied to single aspects of management, such as demography, with cost or efficacy rarely incorporated.We present an analysis of the ranks of management actions for 14 species in five countries that extends beyond the use of demography alone to include multiple metrics for ranking management actions, which integrate cost, efficacy and demography (cost-effectiveness) and managers' expert opinion of ranks. We use content analysis of manager surveys to assess the multiple criteria managers use to rank management strategies.Analysis of the matrix models for managed populations showed that all management actions led to reductions in population growth rate (λ), with a median 48% reduction in λ across all management units; however, only 66% of the actions led to declining populations (λ metrics. Synthesis and applications . A multidimensional view of the benefits and costs of management options provides a range of single and integrated metrics. These rankings, and the relationships between them, can be used to assess management actions for invasive plants. The integrated cost-effectiveness approach goes well 'beyond demography' and provides additional information for managers; however, cost-effectiveness needs to be augmented with information on off-target effects and social impacts of management in order to provide greater benefits for on-the-ground management.

  18. Polymorphic microsatellite markers for population analysis of a tephritid pest species, Bactrocera tryoni.

    Science.gov (United States)

    Kinnear, M W; Bariana, H S; Sved, J A; Frommer, M

    1998-11-01

    To obtain a set of microsatellite markers for the Queensland fruit fly Bactrocera tryoni, a genomic library was screened with a number of simple repeat oligonucleotide probes. Sequencing recovered 22 repeat loci. The microsatellite sequences were short, with repeat numbers ranging from five to 11. Of these, 16 polymerase chain reaction (PCR) primer sets yielded amplifiable products, which were tested on 53 flies from five widely separated sites. All loci showed polymorphism in the population sample, with the number of alleles ranging from two to 16. Several dinucleotide repeats showed alleles separated by single-base differences and multiple steps, suggesting a mutation process more complex than the stepwise mutation model.

  19. Population structure and ecology of a tropical rare rhizomatous species of teosinte Zea diploperennis (Gramineae

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    Lázaro R. Sánchez-Velásquez

    2001-03-01

    Full Text Available One of the objectives of the Sierra de Manantlán Biosphere Reserve (Jalisco, México is the conservation in situ of the teosinte Zea diploperennis Iltis, Doebley, Guzman & Pazzi. Zea diploperennis is perennial, shade intolerant and its 1-3 m shoots are architecturally similar to maize. Clonal growth is of the phalanx type. Genets are iteroparous (modules semelparous. The demography of seven module and genet populations was studied in seven sites representing three stages of old-field succession. Seven permanent one-meter-square plots were randomly established in each site. All genets initially present and those that became established during our study were mapped and labeled according to year of establishment The magnitude of demographic fluctuations was greater in module populations. Genet population dynamics followed a seasonal rhythm with a maximum population size obtained at the onset of the rainy season. A relation was documented between percent annual mortality of a cohort and its age: the younger the cohort, the greater the mortality. This was a statistically significant relationship, Y=[sin(-0.288x + 1.657] ² (r = 0.92, p Se estudió la demografía de Zea diploperennis en siete sitios de cultivo abandonados. La magnitud de las fluctuaciones demográficas fue más grande en las poblaciones de módulos. La dinámica de las poblaciones de genets siguió un ritmo estacional con un tamaño máximo de la población al inicio de la temporada de lluvias; las cohortes más jóvenes presentan la más alta mortalidad, i. e., Y=[ sin(-0.288x + 1.657] ² , (r = 0.92, p < 0.01, donde es la proporción de la mortalidad anual y es la edad de la cohorte. La máxima tasa de mortalidad de genets ocurrió durante la temporada de lluvias cuando la densidad de la población fue más alta, cuando la competencia parece mayor. Hubo relaciones lineales entre la tasa de incremento de genets y el estado sucesional y el tipo de suelo. Aquellas áreas con suelos

  20. Thermal resilience may shape population abundance of two sympatric congeneric Cotesia species (Hymenoptera: Braconidae.

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    Reyard Mutamiswa

    Full Text Available Basal and plasticity of thermal tolerance determine abundance, biogeographical patterns and activity of insects over spatial and temporal scales. For coexisting stemborer parasitoids, offering synergistic impact for biological control, mismatches in thermal tolerance may influence their ultimate impact in biocontrol programs under climate variability. Using laboratory-reared congeneric parasitoid species Cotesia sesamiae Cameron and Cotesia flavipes Cameron (Hymenoptera: Braconidae, we examined basal thermal tolerance to understand potential impact of climate variability on their survival and limits to activity. We measured upper- and lower -lethal temperatures (ULTs and LLTs, critical thermal limits [CTLs] (CTmin and CTmax, supercooling points (SCPs, chill-coma recovery time (CCRT and heat knock-down time (HKDT of adults. Results showed LLTs ranging -5 to 5°C and -15 to -1°C whilst ULTs ranged 35 to 42°C and 37 to 44°C for C. sesamiae and C. flavipes respectively. Cotesia flavipes had significantly higher heat tolerance (measured as CTmax, as well as cold tolerance (measured as CTmin relative to C. sesamiae (P0.05, C. flavipes recovered significantly faster following chill-coma and had higher HKDT compared to C. sesamiae. The results suggest marked differential basal thermal tolerance responses between the two congeners, with C. flavipes having an advantage at both temperature extremes. Thus, under predicted climate change, the two species may differ in phenologies and biogeography with consequences on their efficacy as biological control agents. These results may assist in predicting spatio-temporal activity patterns which can be used in integrated pest management programs under climate variability.

  1. Decline in Endangered Species as an Indication of Anthropic Pressures: The Case of European Mink Mustela lutreola Western Population

    Science.gov (United States)

    Lodé, Thierry; Cormier, Jean-Paul; Le Jacques, Dominique

    2001-12-01

    Populations of threatened species, especially predators at the top of the food chain, may be affected by anthropic pressures. The endangered western population of European mink Mustela lutreola has shown a large decline over 50% of its natural range. M. lutreola disappeared from northwestern France between 1984 and 1997, and the decline was associated with an increase in mustelid trapping, changes in watercourse quality, and habitat modifications due to agricultural practices. The pattern of decline showed a fragmentation restricting the minks into very small areas. Trapping was the first known cause of mortality. Although feral American mink Mustela vison may compete with autochthonous carnivores, M. lutreola had disappeared from streams before the introduction of the American species, suggesting that competitive interactions were not responsible. Furthermore, American mink has never been found or has remained rare in 62.4% of the area from which M. lutreola has disappeared. During the past 25 years, permanent grassland surfaces were reduced by 40%, whereas fodder culture increased by 470%, causing considerable habitat changes. Furthermore, 55.7% of water courses were classified as being of bad quality or polluted. Therefore, our data suggests that a conjunction of intensive trapping, alterations in water quality and habitat modification was critical for the European mink's decline. Although there are difficulties in ascribing specific cause to distribution changes in a top predator, this decline can be regarded as an indication for anthropic pressures on natural habitats.

  2. Tracing early stages of species differentiation: Ecological, morphological and genetic divergence of Galápagos sea lion populations

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    Brunner Sylvia

    2008-05-01

    Full Text Available Abstract Background Oceans are high gene flow environments that are traditionally believed to hamper the build-up of genetic divergence. Despite this, divergence appears to occur occasionally at surprisingly small scales. The Galápagos archipelago provides an ideal opportunity to examine the evolutionary processes of local divergence in an isolated marine environment. Galápagos sea lions (Zalophus wollebaeki are top predators in this unique setting and have an essentially unlimited dispersal capacity across the entire species range. In theory, this should oppose any genetic differentiation. Results We find significant ecological, morphological and genetic divergence between the western colonies and colonies from the central region of the archipelago that are exposed to different ecological conditions. Stable isotope analyses indicate that western animals use different food sources than those from the central area. This is likely due to niche partitioning with the second Galápagos eared seal species, the Galápagos fur seal (Arctocephalus galapagoensis that exclusively dwells in the west. Stable isotope patterns correlate with significant differences in foraging-related skull morphology. Analyses of mitochondrial sequences as well as microsatellites reveal signs of initial genetic differentiation. Conclusion Our results suggest a key role of intra- as well as inter-specific niche segregation in the evolution of genetic structure among populations of a highly mobile species under conditions of free movement. Given the monophyletic arrival of the sea lions on the archipelago, our study challenges the view that geographical barriers are strictly needed for the build-up of genetic divergence. The study further raises the interesting prospect that in social, colonially breeding mammals additional forces, such as social structure or feeding traditions, might bear on the genetic partitioning of populations.

  3. Environmental influences on the species diversity, biomass and population density of soft bottom macrofauna in the estuarine system of Goa, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Harkantra, S.N.; Rodrigues, N.R.

    difference among the sites. The best multiple linear regression model revealed that all the 13 parameters studied were significant influencing parameters on species diversity, biomass and population density with exception of temperature. Among these salinity...

  4. Microstomum (Platyhelminthes, Macrostomorpha, Microstomidae from the Swedish west coast: two new species and a population description

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    Sarah Atherton

    2018-01-01

    Full Text Available Two new species of marine Platyhelminthes, Microstomum laurae sp. nov. and Microstomum edmondi sp. nov. (Macrostomida: Microstomidae are described from the west coast of Sweden. Microstomum laurae sp. nov. is distinguished by the following combination of characters: rounded anterior and posterior ends; presence of approximately 20 adhesive papillae on the posterior rim; paired lateral red eyespots located level with the brain; preoral gut extending anterior to brain and very small sensory pits. Microstomum edmondi sp. nov. is a protandrous hermaphrodite with a single ovary, single testis and male copulatory organ with stylet. It is characterized by a conical pointed anterior end, a blunt posterior end with numerous adhesive papillae along the rim, and large ciliary pits. The stylet is shaped as a narrow funnel with a short, arched tip. In addition, the first records of fully mature specimens of Microstomum rubromaculatum von Graff, 1882 from Fiskebäckskil and a phylogenetic analysis of Microstomum Schmidt, 1848 based on the mitochondrial cytochrome oxidase I (COI gene are presented.

  5. Potential for adaptive evolution at species range margins: contrasting interactions between red coral populations and their environment in a changing ocean.

    Science.gov (United States)

    Ledoux, Jean-Baptiste; Aurelle, Didier; Bensoussan, Nathaniel; Marschal, Christian; Féral, Jean-Pierre; Garrabou, Joaquim

    2015-03-01

    Studying population-by-environment interactions (PEIs) at species range margins offers the opportunity to characterize the responses of populations facing an extreme regime of selection, as expected due to global change. Nevertheless, the importance of these marginal populations as putative reservoirs of adaptive genetic variation has scarcely been considered in conservation biology. This is particularly true in marine ecosystems for which the deep refugia hypothesis proposes that disturbed shallow and marginal populations of a given species can be replenished by mesophotic ones. This hypothesis therefore assumes that identical PEIs exist between populations, neglecting the potential for adaptation at species range margins. Here, we combine reciprocal transplant and common garden experiments with population genetics analyses to decipher the PEIs in the red coral, Corallium rubrum. Our analyses reveal partially contrasting PEIs between shallow and mesophotic populations separated by approximately one hundred meters, suggesting that red coral populations may potentially be locally adapted to their environment. Based on the effective population size and connectivity analyses, we posit that genetic drift may be more important than gene flow in the adaptation of the red coral. We further investigate how adaptive divergence could impact population viability in the context of warming and demonstrate differential phenotypic buffering capacities against thermal stress. Our study questions the relevance of the deep refugia hypothesis and highlights the conservation value of marginal populations as a putative reservoir of adaptive genetic polymorphism.

  6. Strategic rat control for restoring populations of native species in forest fragments.

    Science.gov (United States)

    Armstrong, Doug P; Gorman, Nic; Pike, Rhonda; Kreigenhofer, Brigitte; McArthur, Nikki; Govella, Susanne; Barrett, Paul; Richard, Yvan

    2014-06-01

    Forest fragments have biodiversity value that may be enhanced through management such as control of non-native predators. However, such efforts may be ineffective, and research is needed to ensure that predator control is done strategically. We used Bayesian hierarchical modeling to estimate fragment-specific effects of experimental rat control on a native species targeted for recovery in a New Zealand pastoral landscape. The experiment was a modified BACI (before-after-control-impact) design conducted over 6 years in 19 forest fragments with low-density subpopulations of North Island Robins (Petroica longipes). The aim was to identify individual fragments that not only showed clear benefits of rat control, but also would have a high probability of subpopulation growth even if they were the only fragment managed. We collected data on fecundity, adult and juvenile survival, and juvenile emigration, and modeled the data in an integrated framework to estimate the expected annual growth rate (λ) of each subpopulation with and without rat control. Without emigration, subpopulation growth was estimated as marginal (λ = 0.95-1.05) or negative (λ = 0.74-0.90) without rat control, but it was estimated as positive in all fragments (λ = 1.4-2.1) if rats were controlled. This reflected a 150% average increase in fecundity and 45% average increase in adult female survival. The probability of a juvenile remaining in its natal fragment was 0.37 on average, but varied with fragment connectivity. With juvenile emigration added, 6 fragments were estimated to have a high (>0.8) probability of being self-sustaining (λ > 1) with rat control. The key factors affecting subpopulation growth rates under rat control were low connectivity and stock fencing because these factors were associated with lower juvenile emigration and higher fecundity, respectively. However, there was also substantial random variation in adult survival among fragments, illustrating the importance of

  7. New Species of Fire Discovered: Fingering Flamelets Form a Dynamic Population

    Science.gov (United States)

    Olson, Sandra L.; Miller, Fletcher J.; Wichman, Indrek S.

    2005-01-01

    Poets and artists have long used fire as a metaphor for life. At the NASA Glenn Research Center, recent experiments in a subcritical Rayleigh number flow channel demonstrated that this analogy holds up surprisingly well when tools developed to characterize a biological population are applied to a class of fire that occurs in near-extinction, weakly convective environments (such as microgravity) or in vertically confined spaces (such as our apparatus). Under these conditions, the flame breaks into numerous 'flamelets" that form a Turing-type reaction-diffusion fingering pattern as they spread across the fuel. It is standard practice on U.S. spacecraft for the astronaut crew to turn off the ventilation to help extinguish a fire, both to eliminate the fresh oxygen supply and to reduce the distribution of the smoke. When crew members think that the fire is fully extinguished, they reactivate the ventilation system to clear the smoke. However, some flamelets can survive, and our experiments have demonstrated that flamelets quickly grow into a large fire when ventilation increases.

  8. Dynamic of population-dynamics in a medically important snail species Lymnaea (Radix Luteola (Lamarck

    Directory of Open Access Journals (Sweden)

    T. K. Misra

    1993-09-01

    Full Text Available The life-cycle parameters of the snail Lymnaea (Radix luteola and the factors influencing the same have been studied under laboratory conditions. Ins each month, from July 1990 to June 1991, a batch of 100 zero-day old individual were considered for studies. The snails of April batch survived for 19.42 days while those in December batch survived for 87.45 days. The May batch individual though survived for 65.67 days gained maximum shell size (15.84 mm in length and body weight (419.87 mg. All individuals of April batch died prior to attainment of sexual maturity. In the remaining 11 batches the snails became sexually mature between 32 and 53 days. At this stage, they were with varying shell lengths, 9.3 mm to 13,11 mm in respect to batches. The reproduction period varied from 1-67 days. An individual laid, on an average, 0,25 (March batch to 443.67 (May batch eggs in its life-span. A batch of such snails would leave 24312, 22520, 720268, 80408, 76067, 418165, 214, 9202, 0, 0, 2459386 and 127894 individuals at the end of 352nd day. Since the environmental conditions were almost similar the 'dynamic' of population dynamics seems to be involved with the 'strain' of the snail individuals of the batches concerned.

  9. Insect species interactions and resource effects in treeholes: are helodid beetles bottom-up facilitators of midge populations?

    Science.gov (United States)

    Paradise, C J; Dunson, William A

    1997-01-01

    The insect community living in central Pennsylvania treeholes in autumn consists primarily of larvae of two species of helodid beetles, Prionocyphon discoideus and Helodes pulchella, and larvae of one species of ceratopogonid midge,Culicoides guttipennis. We manipulated treehole volume and the densities of these insects in laboratory microcosms. We hypothesized that: (1) helodid beetle larvae, which are shredders, would enhance growth and survival of ceratopogonid midge larvae (deposit feeders) in a processing chain commensalism, and (2) the quantity of resources expressed as water volume plus leaf litter would affect helodids and protozoans directly. Intraspecific competition was not found in midges, nor was interspecific competition between the two helodid species. Protozoan population densities decreased or grew slower in the presence of insects and in smaller microcosms. Development time and adult wing length of the midge (C. guttipennis) were affected by both total microcosm volume and insect species combination. Under resource limitation, midges grew larger in the presence of helodids, and in general, midges were larger in treatments with higher ratios of helodids to midges. Water chemistry in the microcosms was affected both temporally and by insect presence. Hydrogen ion levels decreased over time, and microcosms with no insects had lower hydrogen ion levels. Specific conductance increased in all treatments over time, and microcosms with no insects had lower conductivity than most treatments. Helodid larvae have a positive effect on midges, possibly due to a processing chain facilitation. If helodids are keystone decomposers in this system, their presence could affect resource availability and affect other organisms in the community. Similar processing chain commensalisms occur in other phytotelmata. These types of interactions may therefore be important in the structure and function of detritus-based communities.

  10. Dietary sources of methylated arsenic species in urine of the United States population, NHANES 2003-2010.

    Directory of Open Access Journals (Sweden)

    B Rey deCastro

    Full Text Available BACKGROUND: Arsenic is an ubiquitous element linked to carcinogenicity, neurotoxicity, as well as adverse respiratory, gastrointestinal, hepatic, and dermal health effects. OBJECTIVE: Identify dietary sources of speciated arsenic: monomethylarsonic acid (MMA, and dimethylarsinic acid (DMA. METHODS: Age-stratified, sample-weighted regression of NHANES (National Health and Nutrition Examination Survey 2003-2010 data (∼8,300 participants ≥6 years old characterized the association between urinary arsenic species and the additional mass consumed of USDA-standardized food groups (24-hour dietary recall data, controlling for potential confounders. RESULTS: For all arsenic species, the rank-order of age strata for median urinary molar concentration was children 6-11 years > adults 20-84 years > adolescents 12-19 years, and for all age strata, the rank-order was DMA > MMA. Median urinary molar concentrations of methylated arsenic species ranged from 0.56 to 3.52 µmol/mol creatinine. Statistically significant increases in urinary arsenic species were associated with increased consumption of: fish (DMA; fruits (DMA, MMA; grain products (DMA, MMA; legumes, nuts, seeds (DMA; meat, poultry (DMA; rice (DMA, MMA; rice cakes/crackers (DMA, MMA; and sugars, sweets, beverages (MMA. And, for adults, rice beverage/milk (DMA, MMA. In addition, based on US (United States median and 90th percentile consumption rates of each food group, exposure from the following food groups was highlighted: fish; fruits; grain products; legumes, nuts, seeds; meat, poultry; and sugars, sweets, beverages. CONCLUSIONS: In a nationally representative sample of the US civilian, noninstitutionalized population, fish (adults, rice (children, and rice cakes/crackers (adolescents had the largest associations with urinary DMA. For MMA, rice beverage/milk (adults and rice cakes/crackers (children, adolescents had the largest associations.

  11. Effects of Cover Crop Species and Season on Population Dynamics of Escherichia coli and Listeria innocua in Soil

    Science.gov (United States)

    Reed-Jones, Neiunna L.; Marine, Sasha Cahn; Everts, Kathryne L.

    2016-01-01

    Cover crops provide several ecosystem services, but their impact on enteric bacterial survival remains unexplored. The influence of cover cropping on foodborne pathogen indicator bacteria was assessed in five cover crop/green manure systems: cereal rye, hairy vetch, crimson clover, hairy vetch-rye and crimson clover-rye mixtures, and bare ground. Cover crop plots were inoculated with Escherichia coli and Listeria innocua in the fall of 2013 and 2014 and tilled into the soil in the spring to form green manure. Soil samples were collected and the bacteria enumerated. Time was a factor for all bacterial populations studied in all fields (P innocua diminished somewhat but persisted, independently of season. In an organic field, the cover crop was a factor for E. coli in year 1 (P = 0.004) and for L. innocua in year 2 (P = 0.011). In year 1, E. coli levels were highest in the rye and hairy vetch-rye plots. In year 2, L. innocua levels were higher in hairy vetch-rye (P = 0.01) and hairy vetch (P = 0.03) plots than in the rye plot. Bacterial populations grew (P innocua numbers were observed after tilling (P innocua abundance in a transitional field (P < 0.05). Overall, the impacts of cover crops/green manures on bacterial population dynamics in soil varied, being influenced by bacterial species, time from inoculation, soil temperature, rainfall, and tillage; this reveals the need for long-term studies. PMID:26729724

  12. A mechanistic approach to link biological effects of radioactive substances from molecules to populations in wildlife species - A mechanistic approach to link biological effects of radionuclides from molecules to populations in wildlife species

    Energy Technology Data Exchange (ETDEWEB)

    Alonzo, Frederic; Parisot, Florian; Plaire, Delphine; Adam-Guillermin, Christelle; Garnier- Laplace, Jacqueline [Institut de Radioprotection et de Surete Nucleaire (IRSN), PRP-ENV, SERIS, LECO, Cadarache, Saint-Paul- Lez-Durance, 13115 (France)

    2014-07-01

    Understanding how toxic contaminants affect wildlife species at various levels of biological organisation (sub-cellular, histological, physiological, organism, population levels) is a major research goal in both ecotoxicology and radioecology. A mechanistic understanding of the links between the different observed perturbations is necessary to predict consequences for survival, growth and reproduction which are critical for population dynamics. However, time scales at which such links are established in the laboratory are rarely relevant for natural populations. With a small size and short life cycle, the cladoceran micro-crustacean Daphnia magna is a particularly suitable biological model for studying effects of radioactive contaminants over several generations. Multi-generational exposures are much more representative of the environmental context of field populations for which contaminations can last for durations which largely exceed individual longevity and involve exposure of many successive generations. Over the last decade, multi-generational investigations of toxic effects were conducted under controlled conditions in D. magna exposed to various radionuclides including depleted uranium, americium-241 and cesium-137, representing respectively a dominantly chemo-toxic metal, an alpha internal contamination and a gamma external radiation. Results showed in all cases that toxic effects on physiology and life history (survival, body size, fecundity) increased in severity across generations. These observations demonstrated that measured effects in one generation might not be representative of toxicity in the following offspring generations, and ultimately of the population response. Reduction in somatic growth and reproduction induced by uranium were analysed using the mechanistic modelling approach known as DEBtox (model of dynamic energy budget applied to toxicology). Modelling results suggested that uranium primarily affects assimilation. This metabolic mode

  13. Changes in agricultural land use can explain population decline in a ladybeetle species in the Czech Republic : evidence from a process-based spatially explicit model

    NARCIS (Netherlands)

    Bianchi, F.J.J.A.; Hon¿k, A.; Werf, van der W.

    2007-01-01

    Changes in land use affect species interactions and population dynamics by modifying the spatial template of trophic interaction and the availability of resources in time and space. We developed a process-based spatially explicit model for evaluating the effects of land use on species viability by

  14. Coarse-scale population structure of pathogenic Armillaria species in a mixed-conifer forest in the Blue Mountains of northeast Oregon.

    Science.gov (United States)

    B.A. Ferguson; T.A. Dreisbach; C.G. Parks; G.M. Filip; C.L. Schmitt

    2003-01-01

    The coarse-scale population structure of pathogenic Armillaria (Fr.) Staude species was determined on approximately 16 100 ha Of relatively dry, mixed-conifer forest in the Blue Mountains of northeast Oregon. Sampling of recently dead or live, symptomatic conifers produced 112 isolates of Armillaria from six tree species.

  15. Mitochondrial DNA polymorphism and heteroplasmy in populations of the three species of Tropidurus of the nanuzae group (Squamata, Tropiduridae

    Directory of Open Access Journals (Sweden)

    José Carlos Passoni

    2000-06-01

    Full Text Available The nanuzae group of lizards includes three species, Tropidurus nanuzae, T. divaricatus and T. amathites. The first species is found along Serra do Espinhaço, in eastern Brazil, and the other two in the northern region of the Brazilian State of Bahia, in continental dunes on both margins of the São Francisco River. Restriction fragment length polymorphisms (RFLP of the mtDNA in these species were detected in 53 restriction sites. Site and fragment length polymorphisms were characterized, and cases of heteroplasmy involving length variation were observed. In T. divaricatus, these variations involved changes of 50-200 bp, probably in the control region of the molecule. In T. amathites, variation was apparently due to duplication/deletion of a 400-bp segment. Fragment length mutation rate varied among the species, being smaller in T. amathites than in T. divaricatus. Relatively low nucleotide diversity values were detected in these populations, the smallest being found in T. nanuzae. The most polymorphic population was T. divaricatus from Alagoado, followed by that of the same species from Ibiraba, suggesting both probable recovery of mtDNA genetic diversity after putative reductions in population size, and recent population expansion.O grupo nanuzae de lagartos compreende três espécies, Tropidurus nanuzae, T. divaricatus e T. amathites. A primeira é encontrada ao longo da Serra do Espinhaço, na região leste do Brasil, e as outras duas na região norte do Estado da Bahia, nas dunas continentais do Rio São Francisco, em margens opostas. Essas três espécies foram analisadas quanto a polimorfismos de tamanho de fragmentos de restrição (RFLP do DNAmit, tendo sido caracterizados 53 sítios de restrição. Polimorfismos de sítio e de tamanho de alguns fragmentos específicos foram caracterizados, bem como casos de heteroplasmia envolvendo variações de tamanho. Em T. divaricatus, estas variações correspondem a 50-200 pb, provavelmente

  16. Morphological and Molecular Data Reveal Three Distinct Populations of Indian Wild Rice Oryza rufipogon Griff. Species Complex

    Science.gov (United States)

    Singh, Balwant; Singh, Nisha; Mishra, Shefali; Tripathi, Kabita; Singh, Bikram P.; Rai, Vandna; Singh, Ashok K.; Singh, Nagendra K.

    2018-01-01

    Wild relatives of crops possess adaptive mutations for agronomically important traits, which could play significant role in crop improvement for sustainable agriculture. However, global climate change and human activities pose serious threats to the natural habitats leading to erosion of genetic diversity of wild rice populations. The purpose of this study was to explore and characterize India’s huge untapped wild rice diversity in Oryza rufipogon Griff. species complex from a wide range of ecological niches. We made strategic expeditions around diversity hot spots in 64 districts of nine different agro-climatic zones of the country and collected 418 wild rice accessions. Significant variation was observed among the accessions for 46 morphological descriptors, allowing classification into O. nivara, O. rufipogon, and O. sativa f. spontanea morpho-taxonomic groups. Genome-specific pSINE1 markers confirmed all the accessions having AA genome, which were further classified using ecotype-specific pSINE1 markers into annual, perennial, intermediate, and an unknown type. Principal component analysis revealed continuous variation for the morphological traits in each ecotype group. Genetic diversity analysis based on multi-allelic SSR markers clustered these accessions into three major groups and analysis of molecular variance for nine agro-climatic zones showed that 68% of the genetic variation was inherent amongst individuals while only 11% of the variation separated the zones, though there was significant correlation between genetic and spatial distances of the accessions. Model based population structure analysis using genome wide bi-allelic SNP markers revealed three sub-populations designated ‘Pro-Indica,’ ‘Pro-Aus,’ and ‘Mid-Gangetic,’ which showed poor correspondence with the morpho-taxonomic classification or pSINE1 ecotypes. There was Pan-India distribution of the ‘Pro-Indica’ and ‘Pro-Aus’ sub-populations across agro-climatic zones

  17. Morphological and Molecular Data Reveal Three Distinct Populations of Indian Wild Rice Oryza rufipogon Griff. Species Complex

    Directory of Open Access Journals (Sweden)

    Balwant Singh

    2018-02-01

    Full Text Available Wild relatives of crops possess adaptive mutations for agronomically important traits, which could play significant role in crop improvement for sustainable agriculture. However, global climate change and human activities pose serious threats to the natural habitats leading to erosion of genetic diversity of wild rice populations. The purpose of this study was to explore and characterize India’s huge untapped wild rice diversity in Oryza rufipogon Griff. species complex from a wide range of ecological niches. We made strategic expeditions around diversity hot spots in 64 districts of nine different agro-climatic zones of the country and collected 418 wild rice accessions. Significant variation was observed among the accessions for 46 morphological descriptors, allowing classification into O. nivara, O. rufipogon, and O. sativa f. spontanea morpho-taxonomic groups. Genome-specific pSINE1 markers confirmed all the accessions having AA genome, which were further classified using ecotype-specific pSINE1 markers into annual, perennial, intermediate, and an unknown type. Principal component analysis revealed continuous variation for the morphological traits in each ecotype group. Genetic diversity analysis based on multi-allelic SSR markers clustered these accessions into three major groups and analysis of molecular variance for nine agro-climatic zones showed that 68% of the genetic variation was inherent amongst individuals while only 11% of the variation separated the zones, though there was significant correlation between genetic and spatial distances of the accessions. Model based population structure analysis using genome wide bi-allelic SNP markers revealed three sub-populations designated ‘Pro-Indica,’ ‘Pro-Aus,’ and ‘Mid-Gangetic,’ which showed poor correspondence with the morpho-taxonomic classification or pSINE1 ecotypes. There was Pan-India distribution of the ‘Pro-Indica’ and ‘Pro-Aus’ sub-populations across agro

  18. Isolation of Campylobacter Species from Stool Samples by Use of a Filtration Method: Assessment from a United States-Based Population.

    Science.gov (United States)

    Nachamkin, Irving; Nguyen, Phi

    2017-07-01

    Fecal samples submitted to our clinical microbiology laboratory from patients in the Philadelphia region were prospectively analyzed for Campylobacter species other than C. jejuni and C. coli using a filtration method and microaerobic conditions with increased H 2 concentrations. Of 225 samples tested, 13 (5.8%) yielded Campylobacter species, with frequent isolation of C. concisus The majority of Campylobacter species were not clinically significant. Additional studies in U.S. populations are warranted. Copyright © 2017 American Society for Microbiology.

  19. Kinetic theory of twisted waves: Application to space plasmas having superthermal population of species

    Science.gov (United States)

    Arshad, Kashif; Poedts, Stefaan; Lazar, Marian

    2017-04-01

    ring shape morphology of a beam with orbital angular momentum (OAM) is ideal for the observation of solar corona around the sun where the intensity of the beam is minimum at the center, in solar experiments, and Earth's ionosphere. The twisted plasma modes carrying OAM are mostly studied either by the fluid theory or Maxwellian distributed Kinetic Theory. But most of the space plasmas and some laboratory plasmas have non-thermal distributions due to super-thermal population of the plasma particles. Therefore the Kinetic Theory of twisted plasma modes carrying OAM are recently studied using non-thermal (kappa) distribution of the super-thermal particles in the presence of the helical electric field and significant change in the damping rates are observed by tuning appropriate parameters.

  20. When Lack of Evidence Is Evidence of Lack.

    Science.gov (United States)

    Pickering, Neil

    2015-12-01

    In their recent article "A Gentle Ethical Defence of Homeopathy," Levy, Gadd, Kerridge, and Komesaroff use the claim that "lack of evidence is not equivalent to evidence of lack" as a component of their ethical defence of homeopathy. In response, this article argues that they cannot use this claim to shore up their ethical arguments. This is because it is false.

  1. Population Structure and Distribution Patterns of the Sibling Mosquito Species Culex pipiens and Culex torrentium (Diptera: Culicidae) Reveal Different Evolutionary Paths

    Science.gov (United States)

    Werblow, Antje; Klimpel, Sven; Bolius, Sarah; Dorresteijn, Adriaan W. C.; Sauer, Jan; Melaun, Christian

    2014-01-01

    Nowadays a number of endemic mosquito species are known to possess vector abilities for various diseases, as e.g. the sibling species Culex pipiens and Culex torrentium. Due to their morphological similarity, ecology, distribution and vector abilities, knowledge about these species' population structure is essential. Culicidae from 25 different sampling sites were collected from March till October 2012. All analyses were performed with aligned cox1 sequences with a total length of 658 bp. Population structure as well as distribution patterns of both species were analysed using molecular methods and different statistical tests like distance based redundancy analysis (dbDRA), analysis of molecular variances (AMOVA) or McDonald & Kreitman test and Tajima's D. Within both species, we could show a genetic variability among the cox1 fragment. The construction of haplotype networks revealed one dominating haplotype for Cx. pipiens, widely distributed within Germany and a more homogeneous pattern for Cx. torrentium. The low genetic differences within Cx. pipiens could be a result of an infection with Wolbachia which can induce a sweep through populations by passively taking the also maternally inherited mtDNA through the population, thereby reducing the mitochondrial diversity as an outcome of reproductive incompatibility. Pairwise population genetic differentiation (FST) ranged significantly from moderate to very great between populations of Cx. pipiens and Cx. torrentium. Analyses of molecular variances revealed for both species that the main genetic variability exists within the populations (Cx. pipiens [88.38%]; Cx. torrentium [66.54%]). Based on a distance based redundancy analysis geographical origin explained a small but significant part of the species' genetic variation. Overall, the results confirm that Cx. pipiens and Cx. torrentium underlie different factors regarding their mitochondrial differentiation, which could be a result of endosymbiosis, dispersal

  2. Defining population structure and genetic signatures of decline in the giant garter snake (Thamnophis gigas): implications for conserving threatened species within highly altered landscapes

    Science.gov (United States)

    Wood, Dustin A.; Halstead, Brian J.; Casazza, Michael L.; Hansen, Eric C.; Wylie, Glenn D.; Vandergast, Amy

    2015-01-01

    Anthropogenic habitat fragmentation can disrupt the ability of species to disperse across landscapes, which can alter the levels and distribution of genetic diversity within populations and negatively impact long-term viability. The giant gartersnake (Thamnophis gigas) is a state and federally threatened species that historically occurred in the wetland habitats of California’s Great Central Valley. Despite the loss of 93 % of historic wetlands throughout the Central Valley, giant gartersnakes continue to persist in relatively small, isolated patches of highly modified agricultural wetlands. Gathering information regarding genetic diversity and effective population size represents an essential component for conservation management programs aimed at this species. Previous mitochondrial sequence studies have revealed historical patterns of differentiation, yet little is known about contemporary population structure and diversity. On the basis of 15 microsatellite loci, we estimate population structure and compare indices of genetic diversity among populations spanning seven drainage basins within the Central Valley. We sought to understand how habitat loss may have affected genetic differentiation, genetic diversity and effective population size, and what these patterns suggest in terms of management and restoration actions. We recovered five genetic clusters that were consistent with regional drainage basins, although three northern basins within the Sacramento Valley formed a single genetic cluster. Our results show that northern drainage basin populations have higher connectivity than among central and southern basins populations, and that greater differentiation exists among the more geographically isolated populations in the central and southern portion of the species’ range. Genetic diversity measures among basins were significantly different, and were generally lower in southern basin populations. Levels of inbreeding and evidence of population

  3. Detecting population structure in a high gene-flow species, Atlantic herring (Clupea harengus): direct, simultaneous evaluation of neutral vs putatively selected loci

    NARCIS (Netherlands)

    Andre, C.; Larsson, L.C.; Laikre, L.; Bekkevold, D.; Brigham, J.; Carvalho, G.R.; Dahlgren, T.G.; Hutchinson, W.F.; Mariani, S.; Mudde, C.M.; Ruzzante, D.E.; Ryman, N.

    2011-01-01

    In many marine fish species, genetic population structure is typically weak because populations are large, evolutionarily young and have a high potential for gene flow. We tested whether genetic markers influenced by natural selection are more efficient than the presumed neutral genetic markers to

  4. Microsatellite DNA analysis of northern pike ( Esox lucius L.) populations: insights into the genetic structure and demographic history of a genetically depauperate species

    DEFF Research Database (Denmark)

    Jacobsen, B. H.; Hansen, Michael Møller; Loeschcke, V.

    2005-01-01

    and southern European populations were highly distinct. A population from Ireland was monomorphic at all loci, presumably reflecting founder events associated with introduction of the species to the island in the sixteenth century. Bayesian analysis of demographic parameters showed differences in theta (a...

  5. Detecting population structure in a high gene-flow species, Atlantic herring (Clupea harengus): direct, simultaneous evaluation of neutral vs putatively selected loci

    DEFF Research Database (Denmark)

    André, C.; Larsson, L. C.; Laikre, L.

    2010-01-01

    In many marine fish species, genetic population structure is typically weak because populations are large, evolutionarily young and have a high potential for gene flow. We tested whether genetic markers influenced by natural selection are more efficient than the presumed neutral genetic markers t...

  6. Population.

    Science.gov (United States)

    International Planned Parenthood Federation, London (England).

    In an effort to help meet the growing interest and concern about the problems created by the rapid growth of population, The International Planned Parenthood Federation has prepared this booklet with the aim of assisting the study of the history and future trends of population growth and its impact on individual and family welfare, national,…

  7. Species delimitation, genetic diversity and population historical dynamics of Cycas diannanensis (Cycadaceae) occurring sympatrically in the Red River region of China.

    Science.gov (United States)

    Liu, Jian; Zhou, Wei; Gong, Xun

    2015-01-01

    Delimitating species boundaries could be of critical importance when evaluating the species' evolving process and providing guidelines for conservation genetics. Here, species delimitation was carried out on three endemic and endangered Cycas species with resembling morphology and overlapped distribution range along the Red River (Yuanjiang) in China: Cycas diananensis Z. T. Guan et G. D. Tao, Cycas parvula S. L. Yang and Cycas multiovula D. Y. Wang. A total of 137 individuals from 15 populations were genotyped by using three chloroplastic (psbA-trnH, atpI-atpH, and trnL-rps4) and two single copy nuclear (RPB1 and SmHP) DNA sequences. Basing on the carefully morphological comparison and cladistic haplotype aggregation (CHA) analysis, we propose all the populations as one species, with the rest two incorporated into C. diannanensis. Genetic diversity and structure analysis of the conflated C. diannanensis revealed this species possessed a relative lower genetic diversity than estimates of other Cycas species. The higher genetic diversity among populations and relative lower genetic diversity within populations, as well as obvious genetic differentiation among populations inferred from chloroplastic DNA (cpDNA) suggested a recent genetic loss within this protected species. Additionally, a clear genetic structure of C. diannanensis corresponding with geography was detected based on cpDNA, dividing its population ranges into "Yuanjiang-Nanhun" basin and "Ejia-Jiepai" basin groups. Demographical history analyses based on combined cpDNA and one nuclear DNA (nDNA) SmHP both showed the population size of C. diannanensis began to decrease in Quaternary glaciation with no subsequent expansion, while another nDNA RPB1 revealed a more recent sudden expansion after long-term population size contraction, suggesting its probable bottleneck events in history. Our findings offer grounded views for clarifying species boundaries of C. diannanensis when determining the conservation

  8. Assessing the risks of pesticides to threatened and endangered species using population modeling: A critical review and recommendations for future work.

    Science.gov (United States)

    Forbes, Valery E; Galic, Nika; Schmolke, Amelie; Vavra, Janna; Pastorok, Rob; Thorbek, Pernille

    2016-08-01

    United States legislation requires the US Environmental Protection Agency to ensure that pesticide use does not cause unreasonable adverse effects on the environment, including species listed under the Endangered Species Act (ESA; hereafter referred to as listed species). Despite a long history of population models used in conservation biology and resource management and a 2013 report from the US National Research Council recommending their use, application of population models for pesticide risk assessments under the ESA has been minimal. The pertinent literature published from 2004 to 2014 was reviewed to explore the availability of population models and their frequency of use in listed species risk assessments. The models were categorized in terms of structure, taxonomic coverage, purpose, inputs and outputs, and whether the models included density dependence, stochasticity, or risk estimates, or were spatially explicit. Despite the widespread availability of models and an extensive literature documenting their use in other management contexts, only 2 of the approximately 400 studies reviewed used population models to assess the risks of pesticides to listed species. This result suggests that there is an untapped potential to adapt existing models for pesticide risk assessments under the ESA, but also that there are some challenges to do so for listed species. Key conclusions from the analysis are summarized, and priorities are recommended for future work to increase the usefulness of population models as tools for pesticide risk assessments. Environ Toxicol Chem 2016;35:1904-1913. © 2016 SETAC. © 2016 SETAC.

  9. Molecular identification and relative abundance of cryptic Lophodermium species in natural populations of Scots pine, Pinus sylvestris L.

    Science.gov (United States)

    Reignoux, Sabrina N A; Green, Sarah; Ennos, Richard A

    2014-01-01

    The multi-locus phylogenetic species recognition approach and population genetic analysis of Amplified Fragment Length Polymorphism (AFLP) markers were used to delineate Lophodermium taxa inhabiting needles of Scots pine (Pinus sylvestris) in native pinewoods within Scotland. These analyses revealed three major lineages corresponding to the morphological species Lophodermium seditiosum and Lophodermium conigenum, fruiting on broken branches, and Lophodermium pinastri, fruiting on naturally fallen needles. Within L. pinastri three well supported sister clades were found representing cryptic taxa designated L. pinastri I, L. pinastri II, and L. pinastri III. Significant differences in mean growth rate in culture were found among the cryptic taxa. Taxon-specific primers based on ITS sequences were designed and used to classify over 500 Lophodermium isolates, derived from fallen needles of P. sylvestris in three Scottish and one French pinewood site, into the three L. pinastri cryptic taxa. Highly significant differences in the relative abundance of the three taxa were found among the Scottish pinewood sites, and between the French and all of the Scottish sites. Copyright © 2014 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  10. [Occurrence and molecular characterization of Babesia species in a canine hospital population in the Londrina Region, Parana State, Brazil].

    Science.gov (United States)

    Shigueru, Flavio Jojima; Garcia, João Luís; Vidotto, Marilda Carlos; Balarin, Mara Regina S; Fabretti, Andrei Kleiton; Gasparini, Marcela R; Coelho, Adriana Letícia M; Vidotto, Odilon

    2008-09-01

    Canine babesiosis is a worldwide disease caused by the protozoan of Babesia genus. Babesia canis and B. gibsoni are both species that naturally infect dogs. The objective of this study was to evaluate the infection of Babesia species in dogs attended at the Londrina State University Veterinary Teaching Hospital (HV-UEL). It was selected 282 dogs seen at the Londrina State University Veterinary Teaching Hospital (HV-UEL) between April of 2005 and May of 2006. They presented anemia (Packed Cell Volume<25%), thrombocytopenia (Platelet count <150000/mm3), leukopenia (White blood cell count<5000/mm3) or a combination of two or three of these alterations at the moment of the consultation. The presence of Babesia sp was determined by the amplification of a specific fragment of DNA of the Babesia genus by PCR. Microscopic examination of Giemsa-stained blood smears detected 38 (13.5%) positive samples against 105 identified by PCR from 282 dogs. The positive samples were submitted to PCR-RFLP by Hinf I that allows distinguishing the species of B. canis vogeli and B. gibsoni. From 282 dogs, Babesia sp infection was identified in 105 (37.2%). From these 105 positive samples, the PCR-RFLP identified 66 (23.4%) samples with a profile compatible to B. canis vogeli and 39 (13, 8%) to B. gibsoni. As conclusions, the results obtained allow to affirm that the babesiose is an important differential for dogs that present anemia, leukopenia and thrombocytopenia and, B. canis vogeli is the subspecies that is present in the most of the cases of babesiose in the population of dogs studied and, that B. gibsoni is also present causing babesiosis in dogs of the Londrina region, Parana State, Brazil.

  11. Relations between species rarity, vulnerability, and range contraction for a beetle group in a densely populated region in the Mediterranean biodiversity hotspot.

    Science.gov (United States)

    Fattorini, Simone

    2014-02-01

    Rarity is often considered an indication of species extinction risk, and it is frequently used to obtain measures of species vulnerability. However, there is no strong evidence of a correlation between species vulnerability and threat. Moreover, there is no consensus about how rarity should be measured. I used a multidimensional characterization of species rarity to calculate a vulnerability index for tenebrionid beetles inhabiting an Italian region in the Mediterranean biodiversity hotspot. I used different metrics to examine 3 dimensions of rarity: species range, ecology, and population. Species with rarity values below the median were scored as rare for each dimension. I combined rarity scores into a vulnerability index. I then correlated species vulnerability with range trends (expanded vs. contracted). Different measures of the same rarity dimension were strongly correlated and produced similar vulnerability scores. This result indicates rarity-based vulnerability estimates are slightly affected by the way a certain rarity dimension is measured. Vulnerability was correlated with range trends; species with the highest vulnerability had the strongest range contraction. However, a large number of common species also underwent range contraction in the last 50 years, and there was no clear relation between range contraction and their ecology. This indicates that in general human-induced environmental changes affected species irrespective of their assumed vulnerability and that focusing only on rare species may severely bias perceptions of the extent of species decline. © 2013 Society for Conservation Biology.

  12. Concept analysis: lack of anonymity.

    Science.gov (United States)

    Swan, Marilyn A; Hobbs, Barbara B

    2017-05-01

    To re-examine and expand understanding of the concept 'lack of anonymity' as a component of rural nursing theory. Early healthcare literature reports lack of anonymity as part of social and working environments, particularly rural nursing. Rural nursing theory included the first published concept analysis on lack of anonymity but lacked empirical referents. Workforce, societal and rural healthcare changes support an updated analysis. To further understand lack of anonymity, its present day use and applicability to diverse environments, research from multiple disciplines was reviewed. Concept analysis. A literature search using eight terms in eleven databases was conducted of literature published between 2008-2013. Walker and Avant's concept analysis methodology guided the analysis. The previous concept analysis is supported in part by current literature. The defining attributes, 'identifiable', 'establishing boundaries for public and private self and interconnectedness' in a community were updated. Updated antecedents include: (i) environmental context; (ii) opportunities to become visible; (iii) developing relationships and (iv) unconscious or limited awareness of public or personal privacy. Consequences are: (i) familiarity; (ii) visibility; (iii) awareness of privacy and (iv) manage or balance of lack of anonymity. Cases were constructed and empirical referents identified. The concept of lack of anonymity was updated; portions of the original definition remain unchanged. Empirical referents reveal the defining attributes in daily life and may guide future research on the effect of lack of anonymity on nursing practice. This analysis advances the conceptual understanding of rural nursing theory. © 2016 John Wiley & Sons Ltd.

  13. Bamboo thickets alter the demographic structure of Euterpe edulis population: A keystone, threatened palm species of the Atlantic forest

    Science.gov (United States)

    Rother, Débora Cristina; Rodrigues, Ricardo Ribeiro; Pizo, Marco Aurélio

    2016-01-01

    The rapid spread of bamboos can strongly affect forest structure by interfering plant regeneration and reducing local biodiversity. Considering that bamboos exert a negative influence on the plant community, our main goal was to investigate how this influence manifests at the population level. We compared the demographic structure of the threatened palm Euterpe edulis between bamboo and non-bamboo dominated patches within the Atlantic forest. In the study site, the native bamboo Guadua tagoara has created a marked patchiness and heterogeneity in the vegetation. Plots were set up randomly in bamboo and non-bamboo patches and the heights of all E. edulis individuals were measured. Data from canopy openness and litter depth were collected for both patches. Greater number of E. edulis was recorded in bamboo patches. However, frequency distribution of the height classes differed between patches revealing a predominance of seedling and sapling I classes in bamboo patches, in comparison to a more evenly distribution of height classes in non-bamboo patches. The canopy in bamboo patches was more open and the litter depth was thicker. Our analyses evidenced G. tagoara is functioning as a demographic bottleneck of natural population of E. edulis by arresting its later stages of regeneration and in high densities that bamboos may limit recruitment of this palm species.

  14. Species delimitation, genetic diversity and population historical dynamics of Cycas diannanensis (Cycadaceae occurring sympatrically in the Red River region of China

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    Liu eJian

    2015-09-01

    Full Text Available Delimitating species boundaries could be of critical importance when evaluating the species’ evolving process and providing guidelines for conservation genetics. Here, species delimitation was carried out on three endemic and endangered Cycas species with resembling morphology and overlapped distribution range along the Red River (Yuanjiang in China: Cycas diananensis Z. T. Guan et G. D. Tao, Cycas parvula S. L. Yang and Cycas multiovula D. Y. Wang. A total of 137 individuals from 15 populations were genotyped by using three chloroplastic (psbA-trnH, atpI-atpH and trnL-rps4 and two single copy nuclear (RPB1 and SmHP DNA sequences. Basing on the carefully morphological comparison and cladistic haplotype aggregation (CHA analysis, we propose all the populations as one species, with the rest two incorporated into C. diannanensis. Genetic diversity and structure analysis of the conflated C. diannanensis revealed this species possessed a relative lower genetic diversity than estimates of other Cycas species. The higher genetic diversity among populations and relative lower genetic diversity within populations, as well as obvious genetic differentiation among populations inferred from chloroplastic DNA (cpDNA suggested a recent genetic loss within this protected species. Additionally, a clear genetic structure of C. diannanensis corresponding with geography was detected based on cpDNA, dividing its population ranges into Yuanjiang-Nanhun basin and Ejia-Jiepai basin groups. Demographical history analyses based on combined cpDNA and one nuclear DNA (nDNA SmHP both showed the population size of C. diannanensis began to decrease in Quaternary glaciation with no subsequent expansion, while another nDNA RPB1 revealed a more recent sudden expansion after long-term population size contraction, suggesting its probable bottleneck events in history. Our findings offer grounded views for clarifying species boundaries of C. diannanensis when determining the

  15. Comparison of Population Genetic Structure of Two Seashore-Dwelling Animal Species, Periwinkle Littorina brevicula and Acorn Barnacle Fistulobalanus albicostatus from Korea

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    Kim, Yuhyun

    2016-04-01

    Full Text Available The genetic structure of marine animals that inhabit the seashore is affected by numerous factors. Of these, gene flow and natural selection during recruitment have strong influences on the genetic structure of seashore-dwelling species that have larval periods. Relative contributions of these two factors to the genetic structure of marine species would be determined mainly by the duration of larval stage. The relationship between larval period and genetic structure of population has been rarely studied in Korea. In this study, genetic variations of cytochrome oxidase subunit I (COI were analyzed in two dominant species on rocky shore habitats in the Korean peninsula: periwinkle Littorina brevicula and acorn barnacle Fistulobalanus albicostatus. Both species are not strongly structured and may have experienced recent population expansion. Unlike periwinkle, however, barnacle populations have considerable genetic variation, and show a bimodal pattern of mismatch distribution. These results suggest that barnacle populations are more affected by local adaptation rather than gene flow via larval migration. The bimodal patterns of barnacle populations observed in mismatch distribution plots imply that they may have experienced secondary contact. Further studies on seashore-dwelling species are expected to be useful in understanding the evolution of the coastal ecosystem around Korean waters.

  16. Adaptive consequences of human-mediated introgression for indigenous tree species: the case of a relict Pinus pinaster population.

    Science.gov (United States)

    Ramírez-Valiente, José Alberto; Robledo-Arnuncio, Juan José

    2014-12-01

    Human-induced gene movement via afforestation and restoration programs is a widespread phenomenon throughout the world. However, its effects on the genetic composition of native populations have received relatively little attention, particularly in forest trees. Here, we examine to what extent gene flow from allochthonous plantations of Pinus pinaster Aiton impacts offspring performance in a neighboring relict natural population and discuss the potential consequences for the long-term genetic composition of the latter. Specifically, we conducted a greenhouse experiment involving two contrasting watering treatments to test for differences in a set of functional traits and mortality rates between P. pinaster progenies from three different parental origins: (i) local native parents, (ii) exotic parents and (iii) intercrosses between local mothers and exotic fathers (intraspecific hybrids). Our results showed differences among crosses in cumulative mortality over time: seedlings of exotic parents exhibited the lowest mortality rates and seedlings of local origin the highest, while intraspecific hybrids exhibited an intermediate response. Linear regressions showed that seedlings with higher water-use efficiency (WUE, δ(13)C) were more likely to survive under drought stress, consistent with previous findings suggesting that WUE has an important role under dry conditions in this species. However, differences in mortality among crosses were only partially explained by WUE. Other non-measured traits and factors such as inbreeding depression in the relict population are more likely to explain the lower performance of native progenies. Overall, our results indicated that intraspecific hybrids and exotic individuals are more likely to survive under stressful conditions than local native individuals, at least during the first year of development. Since summer drought is the most important demographic and selective filter affecting tree establishment in Mediterranean ecosystems

  17. The Henrietta Lacks legacy grows

    OpenAIRE

    Greely, Henry T; Cho, Mildred K

    2013-01-01

    Now that the NIH has reached an agreement with Henrietta Lacks's family concerning the use of the HeLa cell line, what lessons can we learn about informed consent and the unforeseen use of biological samples?

  18. Variation in species diversity and functional traits of sponge communities near human populations in Bocas del Toro, Panama.

    Science.gov (United States)

    Easson, Cole G; Matterson, Kenan O; Freeman, Christopher J; Archer, Stephanie K; Thacker, Robert W

    2015-01-01

    Recent studies have renewed interest in sponge ecology by emphasizing the functional importance of sponges in a broad array of ecosystem services. Many critically important habitats occupied by sponges face chronic stressors that might lead to alterations in their diversity, relatedness, and functional attributes. We addressed whether proximity to human activity might be a significant factor in structuring sponge community composition, as well as potential functional roles, by monitoring sponge diversity and abundance at two structurally similar sites that vary in distance to areas of high coastal development in Bocas Del Toro, Panama. We surveyed sponge communities at each site using belt transects and differences between two sites were compared using the following variables: (1) sponge species richness, Shannon diversity, and inverse Simpson's diversity; (2) phylogenetic diversity; (3) taxonomic and phylogenetic beta diversity; (4) trait diversity and dissimilarity; and (5) phylogenetic and trait patterns in community structure. We observed significantly higher sponge diversity at Punta Caracol, the site most distant from human development (∼5 km). Although phylogenetic diversity was lower at Saigon Bay, the site adjacent to a large village including many houses, businesses, and an airport, the sites did not exhibit significantly different patterns of phylogenetic relatedness in species composition. However, each site had a distinct taxonomic and phylogenetic composition (beta diversity). In addition, the sponge community at Saigon included a higher relative abundance of sponges with high microbial abundance and high chlorophyll a concentration, whereas the community at Punta Caracol had a more even distribution of these traits, yielding a significant difference in functional trait diversity between sites. These results suggest that lower diversity and potentially altered community function might be associated with proximity to human populations. This study

  19. A report of hailstorm damage to two species of freshwater sponge (Demospongiae: Haplosclerida: Spongillidae populations of West Bengal, India

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    Soumalya Mukherjee

    2016-04-01

    Full Text Available Selected freshwater bodies in Jagaddal of North 24 Parganas in West Bengal, India are inhabited by two species of sponge, Eunapius carteri (Bowerbank, 1863 and Spongilla alba (Carter, 1849 (Porifera: Demospongiae: Spongillidae. Most of these wetlands are perennial ponds without a history of aquaculture and toxin contamination. On 22 March 2014, the entire area of Jagaddal experienced an unprecedented hailstorm associated with a sharp decline of environmental temperature from 35 0C to 21 0C within 10–15 minutes. The hailstorm associated with torrential rain lasted for about 30 minutes. The natural habitat of the sponge was visited after six hours of the hailstorm in open day light conditions. During the field investigation, we recorded large-scale damage to the populations of E. carteri and S. alba. Macroscopic observation revealed that the fragmentation of body masses were also associated with cellular disintegration of the external surface. Sponge cells were experimentally dissociated from the sponge fragments and subjected to dye exclusion assay. A vital dye (trypan blue exclusion assay of sponge fragments confirmed a high degree of mortality of the cells of E. carteri and S. alba. Hailstorm associated with the decline of environmental temperature down to 21 0C resulted in the mass destruction of these two species of sponges in their natural habitat. Any unprecedented and acute change in the climatic and hydrological parameter may lead to physiological adversity in the freshwater sponge. Subsequently, recovery from cold shock and mechanical stresses was overcome and a regeneration of sponge specimens was recorded within a period of around six months from the date of the hailstorm. 

  20. The Vietnamese population of Megophrys kuatunensis (Amphibia: Megophryidae) represents a new species of Asian horned frog from Vietnam and southern China.

    Science.gov (United States)

    Tapley, Benjamin; Cutajar, Timothy; Mahony, Stephen; Nguyen, Chung Thanh; Dau, Vinh Quang; Nguyen, Tao Thien; Luong, Hao VAN; Rowley, Jodi J L

    2017-11-08

    The Asian frog genus Megophrys is a diverse group of morphologically conserved, forest-dwelling frogs. The genus harbours highly localised species diversification and new species continue to be described on a regular basis. We examined the taxonomic status of a population of Megophrys frogs from the Hoang Lien Range in northern Vietnam and southern China previously identified as M. kuatunensis (subgenus Panophrys). Preliminary phylogenetic analyses using a fragment of 16S rDNA places the species in question within the Megophrys (subgenus Panophrys) species group, a primarily Chinese radiation within the genus. On the basis of morphological, molecular and bioacoustic data, we conclude that this population does not represent M. kuatunensis, or any known species in the genus. We herein describe this species of Megophrys as new. Known only from Sa Pa District, Lao Cai Province in Vietnam and Jinping County, Yunnan Province in China, the new species is likely to be threatened by ongoing deforestation in the region. We provide an updated species description of M. kuatunensis based on type specimens, and suggest that M. kuatunensis is likely to be restricted to eastern China.

  1. A study of biodiversity using DSS method and seed storage protein comparison of populations in two species of Achillea L. in the west of Iran

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    Hajar Salehi

    2013-11-01

    Full Text Available Intarspecific and interspecific variations are the main reserves of biodiversity and both are important sources of speciation. On this basis, identifing and recognizing the intra and interspecific variations is important in order to recognition of biodiversity. This research was done to study biodiversity and electrophoresis comparison of seed storage proteins in the populations of the two species of the genus Achillea in Hamadan and Kurdistan provinces using of the method of determination of special station (DSS. For this purpose, 12 and 9 special stations were selected for the species A. tenuifolia and A. biebresteinii using the data published in the related flora. Seed storage proteins were extracted and then studied using electrophoresis techniques (SDS-PAGE. In survey of all special stations, 120 plant species were distinguished as associated species. The results of the floristic data for the both species determined six distinctive groups that indicated the existence of intraspecific diversity in this species. The result of analysis of ecological data and seed storage proteins for the two species was in accordance with the floristic data and showed six distinctive groups. The existence of the bands of no. 4, 5, 8, 12 and 13 in the special stations of A. tenuifolia and the bands of 14, 15 and 16 in the special stations of A. biebresteinii o separated the populations of the species in two quite different and distinctive groups.

  2. Morphological, molecular and cross-breeding analysis of geographic populations of coconut-mite associated predatory mites identified as Neoseiulus baraki: evidence for cryptic species?

    Science.gov (United States)

    Famah Sourassou, Nazer; Hanna, Rachid; Zannou, Ignace; Breeuwer, Johannes A J; de Moraes, Gilberto; Sabelis, Maurice W

    2012-05-01

    Surveys were conducted in Brazil, Benin and Tanzania to collect predatory mites as candidates for control of the coconut mite Aceria guerreronis Keifer, a serious pest of coconut fruits. At all locations surveyed, one of the most dominant predators on infested coconut fruits was identified as Neoseiulus baraki Athias-Henriot, based on morphological similarity with regard to taxonomically relevant characters. However, scrutiny of our own and published descriptions suggests that consistent morphological differences may exist between the Benin population and those from the other geographic origins. In this study, we combined three methods to assess whether these populations belong to one species or a few distinct, yet closely related species. First, multivariate analysis of 32 morphological characters showed that the Benin population differed from the other three populations. Second, DNA sequence analysis based on the mitochondrial cytochrome oxidase subunit I (COI) showed the same difference between these populations. Third, cross-breeding between populations was unsuccessful in all combinations. These data provide evidence for the existence of cryptic species. Subsequent morphological research showed that the Benin population can be distinguished from the others by a new character (not included in the multivariate analysis), viz. the number of teeth on the fixed digit of the female chelicera.

  3. Genetic diversity and population structure of the narrow endemic and endangered species Heteroplexis microcephala Y. L. Chen. in China revealed by random amplified polymorphic DNA markers

    Directory of Open Access Journals (Sweden)

    Shi Yancai

    2016-01-01

    Full Text Available Heteroplexis microcephala Y. L. Chen. is an endemic and endangered species found only in karst limestone regions in the Yangshuo County of the Guangxi Zhuang Autonomous Region in China: it is a habitat representative of species in the Heteroplexis genus. To provide basic genetic information for its conservation, in this study we evaluated the genetic variation and differentiation among six wild populations of H. microcephala by random amplified polymorphic DNA markers (RAPD. The leaves of 141 individuals were sampled. Based on 12 primers, 113 DNA fragments were generated. Genetic diversity was low at the population level (Nei’s gene diversity (h=0.0579; Shannon information index (I=0.0924; percentage of polymorphic bands (PPB=23.30%, but relatively high at the species level (h=0.1701; I=0.2551; PPB=46.34%. The coefficient of genetic differentiation based on Nei’s genetic diversity analysis (0.6661 was high, indicating that there was significant genetic differentiation among populations, which was confirmed by AMOVA analysis exhibiting population differentiation among populations of 68.77%. Low gene flow among populations (0.2507 may result from several factors, such as a harsh pollination environment, population isolation and low seed dispersal distance. Limited gene flow and self-compatibility are the primary reasons for the high genetic differentiation observed for this species. We propose the collection of seeds from more populations with fewer individuals and core populations for ex situ conservation and suggest methods to increase seed germination rates.

  4. Population Genetic Structure, Abundance, and Health Status of Two Dominant Benthic Species in the Saba Bank National Park, Caribbean Netherlands: Montastraea cavernosa and Xestospongia muta

    OpenAIRE

    de Bakker, Didier M.; Meesters, Erik H. W. G.; van Bleijswijk, Judith D. L.; Luttikhuizen, Pieternella C.; Breeuwer, Hans J. A. J.; Becking, Leontine E.

    2016-01-01

    Saba Bank, a submerged atoll in the Caribbean Sea with an area of 2,200 km2, has attained international conservation status due to the rich diversity of species that reside on the bank. In order to assess the role of Saba Bank as a potential reservoir of diversity for the surrounding reefs, we examined the population genetic structure, abundance and health status of two prominent benthic species, the coral Montastraea cavernosa and the sponge Xestospongia muta. Sequence data were collected fr...

  5. Climate warming alters effects of management on population viability of threatened species: results from a 30-year experimental study on a rare orchid.

    Science.gov (United States)

    Sletvold, Nina; Dahlgren, Johan P; Oien, Dag-Inge; Moen, Asbjørn; Ehrlén, Johan

    2013-09-01

    Climate change is expected to influence the viability of populations both directly and indirectly, via species interactions. The effects of large-scale climate change are also likely to interact with local habitat conditions. Management actions designed to preserve threatened species therefore need to adapt both to the prevailing climate and local conditions. Yet, few studies have separated the direct and indirect effects of climatic variables on the viability of local populations and discussed the implications for optimal management. We used 30 years of demographic data to estimate the simultaneous effects of management practice and among-year variation in four climatic variables on individual survival, growth and fecundity in one coastal and one inland population of the perennial orchid Dactylorhiza lapponica in Norway. Current management, mowing, is expected to reduce competitive interactions. Statistical models of how climate and management practice influenced vital rates were incorporated into matrix population models to quantify effects on population growth rate. Effects of climate differed between mown and control plots in both populations. In particular, population growth rate increased more strongly with summer temperature in mown plots than in control plots. Population growth rate declined with spring temperature in the inland population, and with precipitation in the coastal population, and the decline was stronger in control plots in both populations. These results illustrate that both direct and indirect effects of climate change are important for population viability and that net effects depend both on local abiotic conditions and on biotic conditions in terms of management practice and intensity of competition. The results also show that effects of management practices influencing competitive interactions can strongly depend on climatic factors. We conclude that interactions between climate and management should be considered to reliably predict

  6. Population differentiation and species cohesion in two closely related plants adapted to neotropical high-altitude 'inselbergs', Alcantarea imperialis and Alcantarea geniculata (Bromeliaceae).

    Science.gov (United States)

    Barbará, T; Martinelli, G; Fay, M F; Mayo, S J; Lexer, C

    2007-05-01

    Isolated granitic rock outcrops or 'inselbergs' may provide a window into the molecular ecology and genetics of continental radiations under simplified conditions, in analogy to the use of oceanic islands in studies of species radiations. Patterns of variability and gene flow in inselberg species have never been thoroughly evaluated in comparison to related taxa with more continuous distribution ranges, or to other species in the same kingdom in general. We use nuclear microsatellites to study population differentiation and gene flow in two diploid, perennial plants adapted to high-altitude neotropical inselbergs, Alcantarea imperialis and Alcantarea geniculata (Bromeliaceae). Population differentiation is pronounced in both taxa, especially in A. imperialis. Gene flow in this species is considerably lower than expected from the literature on plants in general and Bromeliaceae in particular, and too low to prevent differentiation due to drift (N(e)m < 1), unless selection coefficients/effect sizes of favourable alleles are great enough to maintain species cohesion. Low gene flow in A. imperialis indicates that the ability of pollinating bats to promote gene exchange between inselbergs is smaller than previously assumed. Population subdivision in one inselberg population of A. imperialis appears to be associated with the presence of two colour morphs that differ in the coloration of rosettes and bracts. Our results indicate a high potential for inselbergs as venues for studies of the molecular ecology and genetics of continental radiations, such as the one that gave rise to the extraordinary diversity of adaptive strategies and phenotypes seen in Bromeliaceae.

  7. Host heterogeneity influences the impact of a non-native disease invasion on populations of a foundation tree species

    Science.gov (United States)

    Jules, Erik S.; Carroll, Allyson L.; Garcia, Andrea M.; Steenbock, Christopher M.; Kauffman, Matthew J.

    2014-01-01

    Invasive pathogens are becoming increasingly important in forested ecosystems, yet they are often difficult to study because of their rapid transmission. The rate and extent of pathogen spread are thought to be partially controlled by variation in host characteristics, such as when host size and location influence susceptibility. Few host-pathogen systems, however, have been used to test this prediction. We used Port Orford cedar (Chamaecyparis lawsoniana), a foundation tree species in riparian areas of California and Oregon (USA), and the invasive oomycete Phytophthora lateralis to assess pathogen impacts and the role of host characteristics on invasion. Across three streams that had been infected for 13–18 years by P. lateralis, we mapped 2241 trees and determined whether they had been infected using dendrochronology. The infection probability of trees was governed by host size (diameter at breast height [DBH]) and geomorphic position (e.g., active channel, stream bank, floodplain, etc.) similarly across streams. For instance, only 23% of trees trees ≥20 cm DBH were infected. Presumably, because spores of P. lateralis are transported downstream in water, they are more likely to encounter well-developed root systems of larger trees. Also because of this water-transport of spores, differences in infection probability were found across the geomorphic positions: 59% of cedar in the active channel and the stream bank (combined) were infected, while 23% of trees found on higher geomorphic types were infected. Overall, 32% of cedar had been infected across the three streams. However, 63% of the total cedar basal area had been killed, because the greatest number of trees, and the largest trees, were found in the most susceptible positions. In the active channel and stream bank, 91% of the basal area was infected, while 46% was infected across higher geomorphic positions. The invasion of Port Orford cedar populations by P. lateralis causes profound impacts to

  8. Effect of air and noise pollution on species diversity and population density of forest birds at Lalpahari, West Bengal, India.

    Science.gov (United States)

    Saha, Dulal C; Padhy, Pratap K

    2011-11-15

    The Rajmahal-type quality stones for building purposes are found abundantly in Birbhum district, West Bengal, India, where stone mining and crushing have become the main industrial activity. Although crusher dust is injurious to health, demand for crushed stone is ever-increasing as a result of rapid infrastructural growth in the country. Most of the crusher units at Rampurhat are situated along the roadways adjacent to forest under Tumboni Beat of Rampurhat Range of Birbhum Forest Division. Excessive load of air pollution in this area has led to degradation of this forest. The status of the ambient air and noise level was evaluated. The effect of air and noise pollution on abundance and variability of birds in this forest have been compared to an almost non-polluted forest of the same bio-geographic zone. Both species diversity and population density of birds were found to decrease in the polluted forest, especially in the areas adjacent to crushers. For comparing the pollution status of two different forest sites and for establishing whether the density of birds have any correlation between the sites, the Student's t-test and the chi-square test were applied respectively. Most of the results proved to be significant. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Population genetics of indigenous quercus robur L. populations and of derived half-sib families has implications for the reproductive management of the species

    NARCIS (Netherlands)

    Bakker, E.G.; Dam, van B.C.; Eeuwijk, van F.A.; Jacobsen, E.

    2003-01-01

    In the Netherlands indigenous Quercus robur L. populations are rare and have been maintained as patches in ancient woodland. For adequate conservation of these populations, information about genetic variation and population structure is necessary. in order to assess the genetic variation and

  10. Genetic diversity of central and peripheral populations of Toona ciliata var. pubescens, an endangered tree species endemic to China.

    Science.gov (United States)

    Liu, J; Jiang, J M; Chen, Y T

    2014-06-17

    Our objective was to examine the genetic diversity of central and peripheral populations of Toona ciliata var. pubescens, to elucidate whether the central-peripheral hypothesis applies to these populations. We analyzed 392 individuals from nine natural populations using eight pairs of polymorphic SSR primers. The results showed that the mean numbers of observed and expected alleles in peripheral populations were higher than in central populations. Common widespread and rare local (RL) alleles were observed in all populations. However, common local alleles were found in five populations and rare widespread alleles were only found in three. The total numbers of the four types of alleles were higher in peripheral than in central populations, and the quantity of the RL allele was obviously higher in the peripheral populations than in the central populations. Both the observed and expected heterozygosities were higher in peripheral populations compared with the central populations. The coefficient of gene differentiation of the peripheral populations was 0.3045, which was significantly higher than that of the central populations. The gene flow between central populations was greater than one, but less than one between peripheral populations. This indicates that frequent gene flow exists between central populations, while terrain and habitat fragmentation prevent gene flow between peripheral populations. A Mantel test indicated that there was no relationship between genetic and geographical distance of T. ciliata var. pubescens.

  11. Population dynamics of sporogony for Plasmodium vivax parasites from western Thailand developing within three species of colonized Anopheles mosquitoes

    Directory of Open Access Journals (Sweden)

    Sattabongkot Jetsumon

    2006-08-01

    Full Text Available Abstract Background The population dynamics of Plasmodium sporogony within mosquitoes consists of an early phase where parasite abundance decreases during the transition from gametocyte to oocyst, an intermediate phase where parasite abundance remains static as oocysts, and a later phase where parasite abundance increases during the release of progeny sporozoites from oocysts. Sporogonic development is complete when sporozoites invade the mosquito salivary glands. The dynamics and efficiency of this developmental sequence were determined in laboratory strains of Anopheles dirus, Anopheles minimus and Anopheles sawadwongporni mosquitoes for Plasmodium vivax parasites circulating naturally in western Thailand. Methods Mosquitoes were fed blood from 20 symptomatic Thai adults via membrane feeders. Absolute densities were estimated for macrogametocytes, round stages (= female gametes/zygotes, ookinetes, oocysts, haemolymph sporozoites and salivary gland sporozoites. From these census data, five aspects of population dynamics were analysed; 1 changes in life-stage prevalence during early sporogony, 2 kinetics of life-stage formation, 3 efficiency of life-stage transitions, 4 density relationships between successive life-stages, and 5 parasite aggregation patterns. Results There was no difference among the three mosquito species tested in total losses incurred by P. vivax populations during early sporogony. Averaged across all infections, parasite populations incurred a 68-fold loss in abundance, with losses of ca. 19-fold, 2-fold and 2-fold at the first (= gametogenesis/fertilization, second (= round stage transformation, and third (= ookinete migration life-stage transitions, respectively. However, total losses varied widely among infections, ranging from 6-fold to over 2,000-fold loss. Losses during gametogenesis/fertilization accounted for most of this variability, indicating that gametocytes originating from some volunteers were more fertile than

  12. No Genetic Diversity at Molecular Markers and Strong Phenotypic Plasticity in Populations of Ranunculus nodiflorus, an Endangered Plant Species in France

    Science.gov (United States)

    Noel, Florence; Machon, Nathalie; Porcher, Emmanuelle

    2007-01-01

    Background and Aims Although conservation biology has long focused on population dynamics and genetics, phenotypic plasticity is likely to play a significant role in population viability. Here, an investigation is made into the relative contribution of genetic diversity and phenotypic plasticity to the phenotypic variation in natural populations of Ranunculus nodiflorus, a rare annual plant inhabiting temporary puddles in the Fontainebleau forest (Paris region, France) and exhibiting metapopulation dynamics. Methods The genetic diversity and phenotypic plasticity of quantitative traits (morphological and fitness components) were measured in five populations, using a combination of field measurements, common garden experiments and genotyping at microsatellite loci. Key Results It is shown that populations exhibit almost undetectable genetic diversity at molecular markers, and that the variation in quantitative traits observed among populations is due to a high level of phenotypic plasticity. Despite the lack of genetic diversity, the natural population of R. nodiflorus exhibits large population sizes and does not appear threatened by extinction; this may be attributable to large phenotypic plasticity, enabling the production of numerous seeds under a wide range of environmental conditions. Conclusions Efficient conservation of the populations can only be based on habitat management, to favour the maintenance of microenvironmental variation and the resulting strong phenotypic plasticity. In contrast, classical actions aiming to improve genetic diversity are useless in the present case. PMID:17468109

  13. Population genetic structure of the rock outcrop speciesEncholirium spectabile(Bromeliaceae): The role of pollination vs. seed dispersal and evolutionary implications.

    Science.gov (United States)

    Gonçalves-Oliveira, Rodrigo C; Wöhrmann, Tina; Benko-Iseppon, Ana M; Krapp, Florian; Alves, Marccus; Wanderley, Maria das Graças L; Weising, Kurt

    2017-06-01

    Inselbergs are terrestrial, island-like rock outcrop environments that present a highly adapted flora. The epilithic bromeliad Encholirium spectabile is a dominant species on inselbergs in the Caatinga of northeastern Brazil. We conducted a population genetic analysis to test whether the substantial phenotypic diversity of E. spectabile could be explained by limited gene flow among populations and to assess the relative impact of pollen vs. seed dispersal on the genetic structure of the species. Nuclear and chloroplast microsatellite markers were used to genotype E. spectabile individuals from 20 rock outcrop locations, representing four geographic regions: northern Espinhaço Range, Borborema Plateau, southwestern Caatinga and southeastern Caatinga. F -statistics, structure, and other tools were applied to evaluate the genetic makeup of populations. Considerable levels of genetic diversity were revealed. Genetic structuring among populations was stronger on the plastid as compared with the nuclear level, indicating higher gene flow via bat pollination as compared with seed dispersal by wind. structure and AMOVA analyses of the nuclear data suggested a high genetic differentiation between two groups, one containing all populations from the southeastern Caatinga and the other one comprising all remaining samples. The strong genetic differentiation between southeastern Caatinga and the remaining regions may indicate the occurrence of a cryptic species in E. spectabile . The unique genetic composition of each inselberg population suggests in situ conservation as the most appropriate protection measure for this plant lineage. © 2017 Botanical Society of America.

  14. Assessing pesticide risks to threatened and endangered species using population models: Findings and recommendations from a CropLife America Science Forum.

    Science.gov (United States)

    Forbes, V E; Brain, R; Edwards, D; Galic, N; Hall, T; Honegger, J; Meyer, C; Moore, D R J; Nacci, D; Pastorok, R; Preuss, T G; Railsback, S F; Salice, C; Sibly, R M; Tenhumberg, B; Thorbek, P; Wang, M

    2015-07-01

    This brief communication reports on the main findings and recommendations from the 2014 Science Forum organized by CropLife America. The aim of the Forum was to gain a better understanding of the current status of population models and how they could be used in ecological risk assessments for threatened and endangered species potentially exposed to pesticides in the United States. The Forum panelists' recommendations are intended to assist the relevant government agencies with implementation of population modeling in future endangered species risk assessments for pesticides. The Forum included keynote presentations that provided an overview of current practices, highlighted the findings of a recent National Academy of Sciences report and its implications, reviewed the main categories of existing population models and the types of risk expressions that can be produced as model outputs, and provided examples of how population models are currently being used in different legislative contexts. The panel concluded that models developed for listed species assessments should provide quantitative risk estimates, incorporate realistic variability in environmental and demographic factors, integrate complex patterns of exposure and effects, and use baseline conditions that include present factors that have caused the species to be listed (e.g., habitat loss, invasive species) or have resulted in positive management action. Furthermore, the panel advocates for the formation of a multipartite advisory committee to provide best available knowledge and guidance related to model implementation and use, to address such needs as more systematic collection, digitization, and dissemination of data for listed species; consideration of the newest developments in good modeling practice; comprehensive review of existing population models and their applicability for listed species assessments; and development of case studies using a few well-tested models for particular species to

  15. Comparative population genomics of the Borrelia burgdorferi species complex reveals high degree of genetic isolation among species and underscores benefits and constraints to studying intra-specific epidemiological processes.

    Directory of Open Access Journals (Sweden)

    Maude Jacquot

    Full Text Available Lyme borreliosis, one of the most frequently contracted zoonotic diseases in the Northern Hemisphere, is caused by bacteria belonging to different genetic groups within the Borrelia burgdorferi species complex, which are transmitted by ticks among various wildlife reservoirs, such as small mammals and birds. These features make the Borrelia burgdorferi species complex an attractive biological model that can be used to study the diversification and the epidemiology of endemic bacterial pathogens. We investigated the potential of population genomic approaches to study these processes. Sixty-three strains belonging to three species within the Borrelia burgdorferi complex were isolated from questing ticks in Alsace (France, a region where Lyme disease is highly endemic. We first aimed to characterize the degree of genetic isolation among the species sampled. Phylogenetic and coalescent-based analyses revealed clear delineations: there was a ∼50 fold difference between intra-specific and inter-specific recombination rates. We then investigated whether the population genomic data contained information of epidemiological relevance. In phylogenies inferred using most of the genome, conspecific strains did not cluster in clades. These results raise questions about the relevance of different strategies when investigating pathogen epidemiology. For instance, here, both classical analytic approaches and phylodynamic simulations suggested that population sizes and migration rates were higher in B. garinii populations, which are normally associated with birds, than in B. burgdorferi s.s. populations. The phylogenetic analyses of the infection-related ospC gene and its flanking region provided additional support for this finding. Traces of recombination among the B. burgdorferi s.s. lineages and lineages associated with small mammals were found, suggesting that they shared the same hosts. Altogether, these results provide baseline evidence that can be used

  16. Comparative Population Genomics of the Borrelia burgdorferi Species Complex Reveals High Degree of Genetic Isolation among Species and Underscores Benefits and Constraints to Studying Intra-Specific Epidemiological Processes

    Science.gov (United States)

    Jacquot, Maude; Gonnet, Mathieu; Ferquel, Elisabeth; Abrial, David; Claude, Alexandre; Gasqui, Patrick; Choumet, Valérie; Charras-Garrido, Myriam; Garnier, Martine; Faure, Benjamin; Sertour, Natacha; Dorr, Nelly; De Goër, Jocelyn; Vourc'h, Gwenaël; Bailly, Xavier

    2014-01-01

    Lyme borreliosis, one of the most frequently contracted zoonotic diseases in the Northern Hemisphere, is caused by bacteria belonging to different genetic groups within the Borrelia burgdorferi species complex, which are transmitted by ticks among various wildlife reservoirs, such as small mammals and birds. These features make the Borrelia burgdorferi species complex an attractive biological model that can be used to study the diversification and the epidemiology of endemic bacterial pathogens. We investigated the potential of population genomic approaches to study these processes. Sixty-three strains belonging to three species within the Borrelia burgdorferi complex were isolated from questing ticks in Alsace (France), a region where Lyme disease is highly endemic. We first aimed to characterize the degree of genetic isolation among the species sampled. Phylogenetic and coalescent-based analyses revealed clear delineations: there was a ∼50 fold difference between intra-specific and inter-specific recombination rates. We then investigated whether the population genomic data contained information of epidemiological relevance. In phylogenies inferred using most of the genome, conspecific strains did not cluster in clades. These results raise questions about the relevance of different strategies when investigating pathogen epidemiology. For instance, here, both classical analytic approaches and phylodynamic simulations suggested that population sizes and migration rates were higher in B. garinii populations, which are normally associated with birds, than in B. burgdorferi s.s. populations. The phylogenetic analyses of the infection-related ospC gene and its flanking region provided additional support for this finding. Traces of recombination among the B. burgdorferi s.s. lineages and lineages associated with small mammals were found, suggesting that they shared the same hosts. Altogether, these results provide baseline evidence that can be used to formulate

  17. FRESHWATER FISH AND DECAPOD CRUSTACEAN POPULATIONS ON RÉUNION ISLAND, WITH AN ASSESSMENT OF SPECIES INTRODUCTIONS.

    Directory of Open Access Journals (Sweden)

    KEITH P.

    2002-01-01

    Full Text Available Streams of Réunion Island shelter with 26 fish species and 11 decapod crustacean species. Some species have been introduced (18%, some other are endemic to the island or to the Madagascar-Mascarenes region (16.2%, are originated from Indo-Pacific area (35.2% or from Indo-African area (27%. Gobiidae and Palaemonidae are the prevailing family in freshwaters, with the highest number of species. 16 species were introduced, mainly fishes, beginning at the turn of the 19th century, but only 4 of those have become acclimatised, while 7 have disappeared and the status of the other is uncertain.

  18. Species composition, activity patterns and blood meal analysis of sand fly populations (Diptera: Psychodidae) in the metropolitan region of Thessaloniki, an endemic focus of canine leishmaniasis

    Science.gov (United States)

    Species composition, activity patterns and blood meal analysis of sand fly populations were investigated in the metropolitan region of Thessaloniki, North Greece from May to October 2011. Sampling was conducted weekly in 3 different environments (animal facilities, open fields, residential areas) al...

  19. Population and harvest trends of big game and small game species: a technical document supporting the USDA Forest Service Interim Update of the 2000 RPA Assessment

    Science.gov (United States)

    Curtis H. Flather; Michael S. Knowles; Stephen J. Brady

    2009-01-01

    This technical document supports the Forest Service's requirement to assess the status of renewable natural resources as mandated by the Forest and Rangeland Renewable Resources Planning Act of 1974 (RPA). It updates past reports on national and regional trends in population and harvest estimates for species classified as big game and small game. The trends...

  20. Ménage à trois on Macquarie Island: hybridization among three species of fur seal (Arctocephalus spp.) following historical population extinction.

    Science.gov (United States)

    Lancaster, M L; Gemmell, N J; Negro, S; Goldsworthy, S; Sunnucks, P

    2006-10-01

    Human-induced changes to natural systems can cause major disturbances to fundamental ecological and population processes and result in local extinctions and secondary contacts between formerly isolated species. Extensive fur seal harvesting during the nineteenth century on Macquarie Island (subantarctic) resulted in extinction of the original population. Recolonization by three species has been slow and complex, characterized by the establishment of breeding groups of Antarctic and subantarctic fur seals (Arctocephalus gazella and Arctocephalus tropicalis) and presumed nonbreeding (itinerant) male New Zealand fur seals (Arctocephalus forsteri). One thousand and seven pups from eight annual cohorts (1992-2003) were analysed using mitochondrial control region data (RFLP) and 10 microsatellite loci to estimate species composition and hybridization. Antarctic fur seals predominated, but hybridization occurred between all three species (17-30% of all pups). Involvement of New Zealand fur seals was unexpected as females are absent and males are not observed to hold territories during the breeding season. The proportion of hybrids in the population has fallen over time, apparently owing to substantial influxes of pure Antarctic and subantarctic individuals and non-random mating. Over 50% of New Zealand hybrids and 43% of Antarctic-subantarctic hybrids were not F(1), which indicates some degree of hybrid reproductive success, and this may be underestimated: simulations showed that hybrids become virtually undetectable by the third generation of backcrossing. While human impacts seem to have driven novel hybridization in this population, the present 'time slices' analysis suggests some biological resistance to complete homogenization.

  1. Carriage of Staphylococcus species in the veterinary visiting dog population in mainland UK: molecular characterisation of resistance and virulence.

    Science.gov (United States)

    Wedley, Amy L; Dawson, Susan; Maddox, Thomas W; Coyne, Karen P; Pinchbeck, Gina L; Clegg, Peter; Jamrozy, Dorota; Fielder, Mark D; Donovan, David; Nuttall, Tim; Williams, Nicola J

    2014-05-14

    This study investigated the prevalence of nasal carriage of staphylococci in dogs and determined the characteristics of the isolates. A total of 724 dogs from 87 veterinary practices across the mainland UK were screened for carriage of Staphylococcus spp. All isolates were examined for meticillin resistance (MR) and the presence of the mecA gene investigated in those isolates showing resistance. All coagulase-positive staphylococci and MR coagulase-negative staphylococci (MRCoNS) were subjected to antimicrobial susceptibility testing. Spa typing and DNA microarray analysis of resistance and virulence genes was carried out on all MR S. aureus (MRSA) and a subset of meticillin susceptible S. aureus (MSSA). Staphylococci were isolated from 399 (55.1%) of the dogs; only seven (1%) carried MRSA, all of which were identified as the dominant UK healthcare-associated strain (EMRSA-15, ST22). MSSA was identified in 47 (6.5%) dogs, the sequence types of which have been suggested as precursors to successful MRSA clones. Forty (5.5%) dogs carried MRCoNS, while no dogs carried MR S. pseudintermedius, although this is increasingly reported in mainland Europe. Resistance to antimicrobials among the isolates varied between species, with multidrug resistance (MDR) in 87.5% of MRCoNS and 21.8% of coagulase positive staphylococci. Microarray analysis of MRSA and a subset of MSSA isolates identified numerous virulence genes associated with pathogenesis, which are commonly identified in isolates of human origin. However, no isolates carried Panton-Valentine leukocidin (PVL) genes. This study suggests that MRSA carriage is low in the vet visiting dog population, but there is a diverse range of virulence and resistance determinants in canine S. aureus and MRCoNS isolates. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Population Dynamics and Conservation Implications of Decalepis arayalpathra (J. Joseph and V. Chandras.) Venter., a Steno Endemic Species of Western Ghats, India.

    Science.gov (United States)

    Mishra, Priyanka; Kumar, L Dinesh; Kumar, Amit; Gokul, Sivaraman; Ravikumar, Kaliamoorthy; Shukla, Ashutosh K; Sundaresan, Velusamy

    2015-07-01

    Decalepis arayalpathra, a critically endangered plant species, has a restricted and fragmented population in Southern Western Ghats, India. This study is a first attempt to evaluate genetic diversity and population structure in the nine wild populations of D. arayalpathra based on molecular pattern realized through the marker assays. Principal coordinate analysis (PCoA) and Nei's unweighted pair-group method with arithmetic average (UPGMA)-based hierarchical clustering of both the marker assays suggest strong genetic clustering between the individuals corresponding to their geographical ranges. Mantel test also corroborates a close genetic proximity between genetic and geographic data (r = 0.389). Population genetic analysis revealed low levels of gene flow [inter-simple sequence repeat (ISSR) = 0.289 and random amplified polymorphic DNA (RAPD) = 0.847] between the populations, in line with high genetic differentiation (Gst = 0.531 with ISSR and 0.440 with RAPD), which was also supported by analysis of molecular variance (AMOVA), that 54 % (ISSR) and 64 % (RAPD) total variation resided within populations. Bayesian model-based STRUCTURE analysis detected three genetic clusters showing the high degree of admixture within population. Based on the findings, such as inbreeding depression and the loss of genetic diversity, suggestions for conservation strategies are provided to preserve the genetic resources of this endangered species.

  3. Effects of introgression on the genetic population structure of two ecologically and economically important conifer species: lodgepole pine (Pinus contorta var. latifolia) and jack pine (Pinus banksiana).

    Science.gov (United States)

    Cullingham, Catherine I; Cooke, Janice E K; Coltman, David W

    2013-10-01

    Forest trees exhibit a remarkable range of adaptations to their environment, but as a result of frequent and long-distance gene flow, populations are often only weakly differentiated. Lodgepole and jack pine hybridize in western Canada, which adds the opportunity for introgression through hybridization to contribute to population structure and (or) adaptive variation. Access to large sample size, high density SNP datasets for these species would improve our ability to resolve population structure, parameterize introgression, and separate the influence of demography from adaptation. To accomplish this, 454 transcriptome reads for lodgepole and jack pine were assembled using Newbler and MIRA, the assemblies mined for SNPs, and 1536 SNPs were selected for typing on lodgepole pine, jack pine, and their hybrids (N = 536). We identified population structure using both Bayesian clustering and discriminate analysis of principle components. Introgressed SNP loci were identified and their influence on observed population structure was assessed. We found that introgressed loci resulted in increased differentiation both within lodgepole and jack pine populations. These findings are timely given the recent mountain pine beetle population expansion in the hybrid zone, and will facilitate future studies of adaptive traits in these ecologically important species.

  4. An Analysis of the Population Dynamics of Selected Avian Species--With Special References to Changes During the Modern Pesticide Era

    Science.gov (United States)

    Henny, C.J.

    1972-01-01

    The impact of pesticides on the mortality rates and recruitment rates of nongame birds during the last 25 years was evaluated by studying the population dynamics of 16 species. A mathematical model showing the relations between population parameters that yielded stable populations was developed. The information needed for the model included (1) mortality rate schedule (obtained from recoveries of banded birds), (2) recruitment rates, and (3) the age of sexual maturity. The rate of recruitment necessary for a stable population and/or the annual rate of change (increase or decrease) in population levels were estimated. Population parameters were compared to determine whether changes had occurred between time periods (i.e., 1925-45 vs. 1946-65). The great horned owl, red-shouldered hawk, sparrow hawk, osprey, barn owl, Cooper's hawk, red-tailed hawk, great blue heron, blackcrowned night heron, brown pelican, barn swallow, chimney swift, blue jay, blackcapped chickadee, cardinal, and robin were subjected to this analysis. No increase in postfledging mortality rates in any of the species was detected during the last 25 years (since 1945). Since there was no evidence of increased mortality rates it was concluded that accelerated declines in several of the species studied resulted from lowered reproductive success. Mortality rates were found to have decreased in the Cooper's hawk, sparrow hawk, great blue heron, and brown pelican and this was associated with a decrease in shooting pressure. Evidence of lower recruitment rates was found in the brown pelican, osprey, Cooper's hawk, red-shouldered hawk, and sparrow hawk. No changes in recruitment rates were noted in the red-tailed hawk, great horned owl, great blue heron, or barn owl. Information on recruitment rates was not available for comparison with the other species although rates of recruitment essential for a stable population were estimated. This work will provide the basis for making comparisons in future studies

  5. Integrative taxonomy of the ornamental ‘peppermint’ shrimp public market and population genetics of Lysmata boggessi, the most heavily traded species worldwide

    Directory of Open Access Journals (Sweden)

    J. Antonio Baeza

    2017-09-01

    Full Text Available The ornamental trade is a worldwide industry worth >15 billion USD with a problem of rampant product misidentification. Minimizing misidentification is critical in the face of overexploitation of species in the trade. We surveyed the peppermint shrimp ornamental marketplace in the southeastern USA, the most intense market for peppermint shrimps worldwide, to characterize the composition of species in the trade, reveal the extent of misidentification, and describe the population genetics of the true target species. Shrimps were bought from aquarium shops in FL, GA, SC, and NC. We demonstrated, contrary to popular belief (information from dealers, that the most heavily traded species in the market was Lysmata boggessi, an endemic species to the eastern Gulf of Mexico, and not Lysmata wurdemanni. Importantly, only when color pattern or genetic markers in conjunction with morphological traits were employed, was it was possible to unequivocally identify L. boggessi as the only species in the trade. The intensity of the market for peppermint shrimps in the USA has led to L. boggessi being the most traded species worldwide. Misidentification in the shrimp aquarium trade is accidental and involuntary, and is explained by remarkable similarity among congeneric species. Using sequences of the 16S-mt-DNA marker, we found no indication of population genetic structure in the endemic L. boggessi across  550 km of linear coast. Therefore, this species can be considered genetically homogeneous and a single fished stock. Still, we argue in favor of additional studies using more powerful markers (e.g., SNPs capable of revealing genetic structure at a finer spatial-scale. Our results will help advance management and conservation policies in this lucrative yet understudied fishery. Future studies of other ornamental fisheries will benefit from using an integrative taxonomic approach, as we demonstrate here.

  6. Integrative taxonomy of the ornamental ‘peppermint’ shrimp public market and population genetics of Lysmata boggessi, the most heavily traded species worldwide

    Science.gov (United States)

    Behringer, Donald C.

    2017-01-01

    The ornamental trade is a worldwide industry worth >15 billion USD with a problem of rampant product misidentification. Minimizing misidentification is critical in the face of overexploitation of species in the trade. We surveyed the peppermint shrimp ornamental marketplace in the southeastern USA, the most intense market for peppermint shrimps worldwide, to characterize the composition of species in the trade, reveal the extent of misidentification, and describe the population genetics of the true target species. Shrimps were bought from aquarium shops in FL, GA, SC, and NC. We demonstrated, contrary to popular belief (information from dealers), that the most heavily traded species in the market was Lysmata boggessi, an endemic species to the eastern Gulf of Mexico, and not Lysmata wurdemanni. Importantly, only when color pattern or genetic markers in conjunction with morphological traits were employed, was it was possible to unequivocally identify L. boggessi as the only species in the trade. The intensity of the market for peppermint shrimps in the USA has led to L. boggessi being the most traded species worldwide. Misidentification in the shrimp aquarium trade is accidental and involuntary, and is explained by remarkable similarity among congeneric species. Using sequences of the 16S-mt-DNA marker, we found no indication of population genetic structure in the endemic L. boggessi across  550 km of linear coast. Therefore, this species can be considered genetically homogeneous and a single fished stock. Still, we argue in favor of additional studies using more powerful markers (e.g., SNPs) capable of revealing genetic structure at a finer spatial-scale. Our results will help advance management and conservation policies in this lucrative yet understudied fishery. Future studies of other ornamental fisheries will benefit from using an integrative taxonomic approach, as we demonstrate here. PMID:28948100

  7. Integrative taxonomy of the ornamental 'peppermint' shrimp public market and population genetics of Lysmata boggessi, the most heavily traded species worldwide.

    Science.gov (United States)

    Baeza, J Antonio; Behringer, Donald C

    2017-01-01

    The ornamental trade is a worldwide industry worth >15 billion USD with a problem of rampant product misidentification. Minimizing misidentification is critical in the face of overexploitation of species in the trade. We surveyed the peppermint shrimp ornamental marketplace in the southeastern USA, the most intense market for peppermint shrimps worldwide, to characterize the composition of species in the trade, reveal the extent of misidentification, and describe the population genetics of the true target species. Shrimps were bought from aquarium shops in FL, GA, SC, and NC. We demonstrated, contrary to popular belief (information from dealers), that the most heavily traded species in the market was Lysmata boggessi , an endemic species to the eastern Gulf of Mexico, and not Lysmata wurdemanni . Importantly, only when color pattern or genetic markers in conjunction with morphological traits were employed, was it was possible to unequivocally identify L. boggessi as the only species in the trade. The intensity of the market for peppermint shrimps in the USA has led to L. boggessi being the most traded species worldwide. Misidentification in the shrimp aquarium trade is accidental and involuntary, and is explained by remarkable similarity among congeneric species. Using sequences of the 16S-mt-DNA marker, we found no indication of population genetic structure in the endemic L. boggessi across  550 km of linear coast. Therefore, this species can be considered genetically homogeneous and a single fished stock. Still, we argue in favor of additional studies using more powerful markers (e.g., SNPs) capable of revealing genetic structure at a finer spatial-scale. Our results will help advance management and conservation policies in this lucrative yet understudied fishery. Future studies of other ornamental fisheries will benefit from using an integrative taxonomic approach, as we demonstrate here.

  8. Host differentiation and variability of Orobanche crenata populations from legume species in Morocco as revealed by cross-infestation and molecular analysis.

    Science.gov (United States)

    Ennami, Mounia; Briache, Fatima Zahra; Gaboun, Fatima; Abdelwahd, Rabha; Ghaouti, Lamiae; Belqadi, Loubna; Westwood, James; Mentag, Rachid

    2017-08-01

    Orobanche crenata represents a major biotic constraint to production of faba bean and lentil in Morocco. While this parasitic plant attacks both of these crops, the extent to which Orobanche biotypes specialise in parasitising specific crops is unknown. To address this question, we studied O. crenata that grew on different hosts and quantified their host specificity to faba bean and lentil. The virulence of O. crenata populations on each host was investigated through field trials, pot and Petri dishes assays. Genetic diversity of the parasite populations was also assessed through molecular analyses. The two legume species showed distinct patterns of specificity. Faba bean was more susceptible to both O. crenata populations, while the specificity for lentil by lentil-grown O. crenata was evident at the final stage of the parasite life cycle as shown by correspondence factorial analyses. Considerable internal variation (81%) within O. crenata populations parasitising both legume species was observed by molecular analyses, but significant divergence (19%; Ø = 0.189; P = 0.010) among the populations was detected. These results indicate that O. crenata can adapt to specific host species, which is important knowledge when developing integrated pest management practices for parasitic weed control. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  9. Molecular phylogeny and genetic identification of populations of two species of Feirana frogs (Amphibia: Anura, Ranidae, Dicroglossinae, Paini) endemic to China.

    Science.gov (United States)

    Wang, Bin; Jiang, Jianping; Xie, Feng; Chen, Xiaohong; Dubois, Alain; Liang, Gang; Wagner, Steven

    2009-07-01

    Using mitochondrial 12S rRNA, 16S rRNA, and ND2 sequences, we investigated phylogenetic relationships among populations of two frog species endemic to China, both referred to the genus Feirana. A sister-group relationship between the two species was supported moderately in a maximum likelihood analysis and significantly in a Bayesian analysis, but not in a maximum parsimony analysis, of combined data for the three genes. Pending resolution of this incongruence, we provisionally maintain these species in the genus Feirana. Two major clades with a deep divergence are concordant with the species F. quadranus and "F." taihangnica. In the present work, some populations from the Qinling Mountains and all those from the Funiu and the Zhongtiao-southern Taihang Mountains are referred to "F." taihangnica rather than F. quadranus, whereas others are referred to F. quadranus. Consequently, the main body of the Qinling Mountains was identified as a large contact zone between these two species. On the basis of phylogenetic relationships and the distribution pattern of populations, we propose a hypothesis for the divergence of "F." taihangnica: the ancestral species might have inhabited the westernmost Qinling Mountains and dispersed to the main Qinling Mountains, and then to the Zhongtiao-southern Taihang and Funiu Mountains. In contrast, two alternative hypotheses are suggested for F. quadranus: if the two species are confirmed as sister groups, F. quadranus might have dispersed from the westernmost Qinling to the Longmen, Qinling, Daba, and northern Wuling Mountains; alternatively, F. quadranus might have come from the northern Wuling Mountains and then dispersed to the Daba, Qinling, and Longmen mountains.

  10. Lack of evidence for co-speciation in a parasitic nematode of grey kangaroos.

    Science.gov (United States)

    Chilton, N B; Morris, G M; Beveridge, I; Coulson, G

    2004-09-01

    Multilocus enzyme electrophoresis was used to compare specimens of the parasitic nematode Cloacina obtusa from the stomach of the eastern grey kangaroo, Macropus giganteus and the western grey kangaroo, M. fuliginosus. Allelic variation among nematodes was detected at 17 (85%) of 20 loci, but there was only a single fixed genetic difference (at the locus for isocitrate dehydrogenase, IDH) between C. obtusa from M. fuliginosus and those from M. giganteus in areas where each host occurred in allopatry. However, this fixed difference was not apparent within the zone of host sympatry. Although electrophoretic data indicate genetic divergence among allopatric populations of C. obtusa in the two host species, the magnitude of the electrophoretic difference (5%) between these populations does not refute the hypothesis that C. obtusa represents a single species. The 'usual' situation for parasitic helminths of grey kangaroos is that pairs of parasite species occur in the two host species. This situation differs for C. obtusa, where there has been a lack of speciation following a speciation event in its macropodid marsupial hosts. This finding suggests that a speciation event in the host does not necessarily lead to a speciation event for all its parasites and further highlights our lack of understanding of which processes drive speciation in parasites.

  11. Babesia behnkei sp. nov., a novel Babesia species infecting isolated populations of Wagner's gerbil, Dipodillus dasyurus, from the Sinai Mountains, Egypt.

    Science.gov (United States)

    Bajer, Anna; Alsarraf, Mohammed; Bednarska, Małgorzata; Mohallal, Eman M E; Mierzejewska, Ewa J; Behnke-Borowczyk, Jolanta; Zalat, Sammy; Gilbert, Francis; Welc-Falęciak, Renata

    2014-12-09

    Although a number of new species of Babesia/Theileria have been described recently, there are still relatively few reports of species from Africa. In this study based on the evaluation of morphology and phylogenetic relationships, we describe a novel species from Wagner's gerbil, Babesia behnkei n. sp. Rodents (n = 1021) were sampled in four montane valleys (wadies) in 2000, 2004, 2008 and 2012 in the Sinai Mountains, Egypt. The overall prevalence of Babesia spp. was highest in the Wagner's gerbil (Dipodillus dasyurus; 38.7%) in comparison to the prevalence in the spiny mice species, Acomys dimidiatus and A. russatus. Morphological investigations were conducted for the comparison of trophozoites of the novel species of Babesia with the B. microti King's 67 reference strain. Thirty-two isolates derived from D. dasyurus over a 9 year period (2004-2012) from two wadies (29 isolates from Wadi Gebel and 3 from Wadi El-Arbaein) were investigated by microscopic, molecular and phylogenetic analysis. A near-full-length sequence of the 18S rRNA gene and the second internal transcribed spacer (ITS2) region were amplified, sequenced and used for the construction of phylogenetic trees. A novel species of Babesia was identified in two isolated populations of D. dasyurus. Phylogenetic analysis of 18S rDNA and ITS2 sequences revealed that B. behnkei n. sp. is most closely related to B. lengau from cheetahs from South Africa and to Nearctic species found only in North America (the pathogenic B. duncani and B. conradae) and that it is more distant to the cosmopolitan rodent parasite B. microti. Trophozoites of B. behnkei were smaller and less polymorphic than trophozoites of B. microti. Babesia behnkei n. sp. is a novel species of the 'Duncani group' maintained in isolated populations of Dipodillus dasyurus occurring in the Sinai Mountains of Egypt.

  12. Screening mitochondrial DNA sequence variation as an alternative method for tracking established and outbreak populations of Queensland fruit fly at the species southern range limit.

    Science.gov (United States)

    Blacket, Mark J; Malipatil, Mali B; Semeraro, Linda; Gillespie, Peter S; Dominiak, Bernie C

    2017-04-01

    Understanding the relationship between incursions of insect pests and established populations is critical to implementing effective control. Studies of genetic variation can provide powerful tools to examine potential invasion pathways and longevity of individual pest outbreaks. The major fruit fly pest in eastern Australia, Queensland fruit fly Bactrocera tryoni (Froggatt), has been subject to significant long-term quarantine and population reduction control measures in the major horticulture production areas of southeastern Australia, at the species southern range limit. Previous studies have employed microsatellite markers to estimate gene flow between populations across this region. In this study, we used an independent genetic marker, mitochondrial DNA (mtDNA) sequences, to screen genetic variation in established and adjacent outbreak populations in southeastern Australia. During the study period, favorable environmental conditions resulted in multiple outbreaks, which appeared genetically distinctive and relatively geographically localized, implying minimal dispersal between simultaneous outbreaks. Populations in established regions were found to occur over much larger areas. Screening mtDNA (female) lineages proved to be an effective alternative genetic tool to assist in understanding fruit fly population dynamics and provide another possible molecular method that could now be employed for better understanding of the ecology and evolution of this and other pest species.

  13. Phylogenetic and population genetic analyses of Phaeosphaeria nodorum and its close relatives indicate cryptic species and an origin in the Fertile Crescent.

    Science.gov (United States)

    McDonald, Megan C; Razavi, Mohammad; Friesen, Timothy L; Brunner, Patrick C; McDonald, Bruce A

    2012-11-01

    The origin of the fungal wheat pathogen Phaeosphaeria nodorum remains unclear despite earlier intensive global population genetic and phylogeographical studies. We sequenced 1683 bp distributed across three loci in 355 globally distributed Phaeosphaeria isolates, including 74 collected in Iran near the center of origin of wheat. We identified nine phylogenetically distinct clades, including two previously unknown species tentatively named P1 and P2 collected in Iran. Coalescent analysis indicates that P1 and P2 are sister species of P. nodorum and the other Phaeosphaeria species identified in our analysis. Two species, P. nodorum and P. avenaria f. sp. tritici 1 (Pat1), comprised ~85% of the sampled isolates, making them the dominant wheat-infecting pathogens within the species complex. We designed a PCR-RFLP assay to distinguish P. nodorum from Pat1. Approximately 4% of P. nodorum and Pat1 isolates showed evidence of hybridization. Measures of private allelic richness at SSR and sequence loci suggest that the center of origin of P. nodorum coincides with its host in the Fertile Crescent. We hypothesize that the origin of this species complex is also in the Fertile Crescent, with four species out of nine found exclusively in the Iranian collections. Copyright © 2012 Elsevier Inc. All rights reserved.

  14. Conservation Action Based on Threatened Species Capture Taxonomic and Phylogenetic Richness in Breeding and Wintering Populations of Central Asian Birds

    Science.gov (United States)

    Schweizer, Manuel; Ayé, Raffael; Kashkarov, Roman; Roth, Tobias

    2014-01-01

    Although phylogenetic diversity has been suggested to be relevant from a conservation point of view, its role is still limited in applied nature conservation. Recently, the practice of investing conservation resources based on threatened species was identified as a reason for the slow integration of phylogenetic diversity in nature conservation planning. One of the main arguments is based on the observation that threatened species are not evenly distributed over the phylogenetic tree. However this argument seems to dismiss the fact that conservation action is a spatially explicit process, and even if threatened species are not evenly distributed over the phylogenetic tree, the occurrence of threatened species could still indicate areas with above average phylogenetic diversity and consequently could protect phylogenetic diversity. Here we aim to study the selection of important bird areas in Central Asia, which were nominated largely based on the presence of threatened bird species. We show that although threatened species occurring in Central Asia do not capture phylogenetically more distinct species than expected by chance, the current spatially explicit conservation approach of selecting important bird areas covers above average taxonomic and phylogenetic diversity of breeding and wintering birds. We conclude that the spatially explicit processes of conservation actions need to be considered in the current discussion of whether new prioritization methods are needed to complement conservation action based on threatened species. PMID:25337861

  15. Conservation action based on threatened species capture taxonomic and phylogenetic richness in breeding and wintering populations of Central Asian birds.

    Directory of Open Access Journals (Sweden)

    Manuel Schweizer

    Full Text Available Although phylogenetic diversity has been suggested to be relevant from a conservation point of view, its role is still limited in applied nature conservation. Recently, the practice of investing conservation resources based on threatened species was identified as a reason for the slow integration of phylogenetic diversity in nature conservation planning. One of the main arguments is based on the observation that threatened species are not evenly distributed over the phylogenetic tree. However this argument seems to dismiss the fact that conservation action is a spatially explicit process, and even if threatened species are not evenly distributed over the phylogenetic tree, the occurrence of threatened species could still indicate areas with above average phylogenetic diversity and consequently could protect phylogenetic diversity. Here we aim to study the selection of important bird areas in Central Asia, which were nominated largely based on the presence of threatened bird species. We show that although threatened species occurring in Central Asia do not capture phylogenetically more distinct species than expected by chance, the current spatially explicit conservation approach of selecting important bird areas covers above average taxonomic and phylogenetic diversity of breeding and wintering birds. We conclude that the spatially explicit processes of conservation actions need to be considered in the current discussion of whether new prioritization methods are needed to complement conservation action based on threatened species.

  16. Scale-dependence of the correlation between human population and the species richness of stream macro-invertebrates

    DEFF Research Database (Denmark)

    Pecher, C.; Fritz, Susanne; Marini, L.

    2010-01-01

    . This is surprising as EPT are bio-indicators of stream pollution and most local studies report higher species richness of these macro-invertebrates where human influences on water quality are lower. Using a newly collated taxonomic dataset, we studied whether the species richness of EPT is related to human...

  17. Phylogeny of Fomitopsis pinicola: A species complex

    Science.gov (United States)

    John Haight; Gary A. Laursen; Jessie A. Glaeser; D. Lee. Taylor

    2016-01-01

    Fungal species with a broad distribution may exhibit considerable genetic variation over their geographic ranges. Variation may develop among populations based on geographic isolation, lack of migration, and genetic drift, though this genetic variation may not always be evident when examining phenotypic characters. Fomitopsis pinicola is an...

  18. From species divergence to population structure: a multimarker approach on the most basal lineage of Salamandridae, the spectacled salamanders (genus Salamandrina) from Italy.

    Science.gov (United States)

    Hauswaldt, J Susanne; Angelini, Claudio; Gehara, Marcelo; Benavides, Edgar; Polok, Andy; Steinfartz, Sebastian

    2014-01-01

    The Apennine Peninsula is one of Europe's main glacial refugial areas and harbors a large number of lineages and species. Here, a pattern of higher genetic diversity in the south compared to that of the north is characteristic of most vertebrates; however, most studies that have produced these results have relied only on inferences based on mitochondrial DNA. The spectacled salamanders (genus Salamandrina) are endemic to the Apennine Peninsula and have diverged into two sibling species: S. terdigitata (in the south) and S. perspicillata (in the north), presumably in the late Miocene or early Pliocene. By sequencing one mitochondrial (cytb) and two nuclear genes (RAG1 and POMC) and genotyping 10 microsatellite loci, we traced the evolution of these sibling species from their divergence to their contemporary population structure at a fine scale. Using a multilocus coalescent-based approach, we estimated the temporal divergence of both species at approximately 2.25 mya (million years ago), which, hence, is much younger than previous estimates. The classical pattern of high genetic diversity in the south and lower diversity in the north was confirmed only for some markers, and the demographic histories of the two species differed substantially. Whereas S. perspicillata (north) expanded from a single major refugium in the center of the Apennine Peninsula, populations of S. terdigitata (south) persisted through cooler periods in multiple refugia. Further, the fine-scale population genetic structure of 16 S. perspicillata populations revealed significant genetic differentiation, even across short geographic distances. The results of our study stress that for a better understanding of phylogeographic patterns and past demographic processes, both mitochondrial and multiple nuclear loci should be analyzed to avoid gene-specific, and possibly biased results. Copyright © 2013 Elsevier Inc. All rights reserved.

  19. Species traits and catchment-scale habitat factors influence the occurrence of freshwater mussel populations and assemblages

    Science.gov (United States)

    Pandolfo, Tamara J.; Kwak, Thomas J.; Cope, W. Gregory; Heise, Ryan J.; Nichols, Robert B.; Pacifici, Krishna

    2016-01-01

    Conservation of freshwater unionid mussels presents unique challenges due to their distinctive life cycle, cryptic occurrence and imperilled status. Relevant ecological information is urgently needed to guide their management and conservation.We adopted a modelling approach, which is a novel application to freshwater mussels to enhance inference on rare species, by borrowing data among species in a hierarchical framework to conduct the most comprehensive occurrence analysis for freshwater mussels to date. We incorporated imperfect detection to more accurately examine effects of biotic and abiotic factors at multiple scales on the occurrence of 14 mussel species and the entire assemblage of the Tar River Basin of North Carolina, U.S.A.The single assemblage estimate of detection probability for all species was 0.42 (95% CI, 0.36–0.47) with no species- or site-specific detection effects identified. We empirically observed 15 mussel species in the basin but estimated total species richness at 21 (95% CI, 16–24) when accounting for imperfect detection.Mean occurrence probability among species ranged from 0.04 (95% CI, 0.01–0.16) for Alasmidonta undulata, an undescribed Lampsilis sp., and Strophitus undulatus to 0.67 (95% CI, 0.42–0.86) for Elliptio icterina. Median occurrence probability among sites was management can benefit an entire assemblage, but species-specific strategies may be necessary for successful conservation. The hierarchical multispecies modelling approach revealed findings that could not be elucidated by other means, and the approach may be applied more broadly to other river basins and regions. Accurate measures of assemblage dynamics, such as occurrence and species richness, are required to create management plans for effective conservation.

  20. Specific IgE to fish extracts does not predict allergy to specific species within an adult fish allergic population.

    Science.gov (United States)

    Schulkes, Karlijn Jg; Klemans, Rob Jb; Knigge, Lidy; de Bruin-Weller, Marjolein; Bruijnzeel-Koomen, Carla Afm; Marknell deWitt, Asa; Lidholm, Jonas; Knulst, André C

    2014-01-01

    Fish is an important cause of food allergy. Studies on fish allergy are scarce and in most cases limited to serological evaluation. Our objective was to study patterns of self-reported allergy and tolerance to different commonly consumed fish species and its correlation to IgE sensitization to the same species. Thirty-eight adult fish allergic patients completed a questionnaire regarding atopy, age of onset and symptoms to 13 commonly consumed fish species in the Netherlands (pangasius, cod, herring, eel, hake, pollock, mackerel, tilapia, salmon, sardine, tuna, plaice and swordfish). Specific IgE to these fish extracts were analyzed by ImmunoCAP. Median age of onset of fish allergy was 8.5 years. Severe reactions were reported by the majority of patients (n = 20 (53%) respiratory and of these 20 patients, 6 also had cardiovascular symptoms). After diagnosis, 66% of the patients had eliminated all fish from their diet. Allergy to all species ever tried was reported by 59%. In relation to species ever tried, cod (84%) and herring (79%) were the most frequently reported culprit species while hake (57%) and swordfish (55%) were the least frequent. A positive sIgE (value ≥ 0.35 kUA/L) to the culprit species ranged between 50% (swordfish) and 100% (hake). In tolerant patients, a negative sIgE (value allergy or tolerance was 82% and 25%, respectively. Sensitization to cod parvalbumin (Gad c 1) was present in 77% of all patients. Serological cross-reactivity between fish species is frequent, but in a significant proportion of patients, clinical relevance appears to be limited to only certain species. A well-taken history or food challenge is required for discrimination between allergy to the different fish species.

  1. The genetic structure of populations of an invading pest fruit fly, Bactrocera tryoni, at the species climatic range limit.

    Science.gov (United States)

    Gilchrist, A S; Meats, A W

    2010-08-01

    Previous population genetic studies of the Queensland fruit fly, Bactrocera tryoni Froggatt (Diptera: Tephritidae), in its central range have shown barely detectable genetic differentiation across distances of almost 3000 km (F(st)=0.003). In this study, we investigated the genetic structuring of southern border populations of B. tryoni, in the region extending from the central population to the recently colonized southern range limit. The expectation was that marginal populations would be small, fragmented population sinks, with local adaptation limited by gene flow or drift. Unexpectedly, we found that the population at the southern extreme of the range was a source population, rather than a sink, for the surrounding region. This was shown by assignment testing of recent outbreaks in an adjoining quarantine area and by indirect migration estimates. Furthermore, populations in the region had formed a latitudinal cline in microsatellite allele frequencies, spanning the region between the central population and the southern range limit. The cline has formed within 250 generations of the initial invasion and appears stable between years. We show that there is restricted gene flow in the region and that effective population sizes are of the order of 10(2)-10(3). Although the cline may result from natural selection, neutral evolutionary processes may also explain our findings.

  2. Fine-scale population dynamics in a marine fish species inferred from dynamic state-space models.

    Science.gov (United States)

    Rogers, Lauren A; Storvik, Geir O; Knutsen, Halvor; Olsen, Esben M; Stenseth, Nils C

    2017-07-01

    Identifying the spatial scale of population structuring is critical for the conservation of natural populations and for drawing accurate ecological inferences. However, population studies often use spatially aggregated data to draw inferences about population trends and drivers, potentially masking ecologically relevant population sub-structure and dynamics. The goals of this study were to investigate how population dynamics models with and without spatial structure affect inferences on population trends and the identification of intrinsic drivers of population dynamics (e.g. density dependence). Specifically, we developed dynamic, age-structured, state-space models to test different hypotheses regarding the spatial structure of a population complex of coastal Atlantic cod (Gadus morhua). Data were from a 93-year survey of juvenile (age 0 and 1) cod sampled along >200 km of the Norwegian Skagerrak coast. We compared two models: one which assumes all sampled cod belong to one larger population, and a second which assumes that each fjord contains a unique population with locally determined dynamics. Using the best supported model, we then reconstructed the historical spatial and temporal dynamics of Skagerrak coastal cod. Cross-validation showed that the spatially structured model with local dynamics had better predictive ability. Furthermore, posterior predictive checks showed that a model which assumes one homogeneous population failed to capture the spatial correlation pattern present in the survey data. The spatially structured model indicated that population trends differed markedly among fjords, as did estimates of population parameters including density-dependent survival. Recent biomass was estimated to be at a near-record low all along the coast, but the finer scale model indicated that the decline occurred at different times in different regions. Warm temperatures were associated with poor recruitment, but local changes in habitat and fishing pressure may

  3. Competition among native and invasive Impatiens species: the roles of environmental factors, population density and life stage.

    Science.gov (United States)

    Čuda, Jan; Skálová, Hana; Janovský, Zdeněk; Pyšek, Petr

    2015-04-01

    Many invasive species are considered competitively superior to native species, with the strongest competition expected in species with similar niches and/or in closely related species. However, competition outcome is strongly context-dependent as competitive strength varies along environmental gradients, and life stages, and also depends on abundances. To explore the importance of these factors, we examined competition effects in an experiment with three Impatiens species (Balsaminaceae) widespread in central Europe and sharing similar life-history characteristics and habitats: the native I. noli-tangere, and two invasive species, I. parviflora and I. glandulifera. We compared their competitive strength and reciprocal impacts under two levels of water and light availability, two overall planting densities and three competitor densities. We assessed species performance (ability to complete the life-cycle, biomass and fecundity) and temporal competition dynamics in a garden pot experiment. Environmental variables had lower explanatory power than overall planting and competitor density, which indicates the importance of competitive interactions when evaluating plant performance and potential invasion success. Despite poor and delayed germination, the invasive I. glandulifera attained dominance even at a high competitor density and was competitively superior across all treatments, exceeding the height of both congeners. Impatiens parviflora was competitively weakest, having a negligible impact on both native I. noli-tangere and invasive I. glandulifera. The intermediate competitive strength of the native I. noli-tangere probably results from its intermediate height, and good germination rate and timing. The difference in height among species increased during the experiment when I. glandulifera was involved; this species continues growing until autumn, enhancing its competitive superiority. The results provide a mechanistic understanding for the competitive exclusion of

  4. Optimizing conservation of migratory species over their full annual cycle in the Western Hemisphere

    OpenAIRE

    Bennett, Joseph; Auer, Tom; Fink, Daniel; Arcese, Peter; Rodewald, Amanda; Wilson, Scott; Schuster, Richard

    2018-01-01

    Strategic plans to conserve migratory species require detailed knowledge on species distribution, abundance, and habitat use over the annual cycle, but such data are lacking for most species. We developed a hemispheric approach to planning using spatiotemporally explicit species abundance models to prioritize land needed to conserve ≥17% of the global populations of 109 species of Neotropical migratory birds. The efficiency of annual cycle plans was evaluated in comparisons to single-season p...

  5. Molecular assessment of Podarcis sicula populations in Britain, Greece and Turkey reinforces a multiple-origin invasion pattern in this species

    Directory of Open Access Journals (Sweden)

    Iolanda Silva-Rocha

    2014-12-01

    Full Text Available Biological invasions are a challenge to conservation and constitute a threat to biodiversity worldwide. The Italian wall lizard Podarcis sicula has been widely introduced, and seems capable of adapting to most of the regions where it is established and to impact on native biota. Here we construct a phylogenetic framework to assess the origin of the introduced populations in the United Kingdom, Greece and Turkey comparing cytochrome-b gene sequences of lizards from five locations to published sequences from the native range and other non-native locations. The results support an origin from central Italy for the United Kingdom population, from the Adriatic region for the Greek population and from Calabria for the population from Turkey. These results emphasise the multiple-source pattern of introduction of this species identified in previous studies. The improvement in the knowledge of the origin and pathways by which invaders arrive in new areas, as well as the monitoring of their populations, are crucial for successful strategies to deal with exotic species.

  6. 76 FR 76386 - Endangered and Threatened Species; 5-Year Reviews for 4 Distinct Population Segments of Steelhead...

    Science.gov (United States)

    2011-12-07

    ... reviews for listed Pacific salmon ESUs and steelhead DPSs in California, Oregon, Washington, and Idaho (75... status of each species. They also considered new genetic and biogeographic information related to each...

  7. Population dynamics of the felted beech scale and associated Neonectria species, causal agents of beech bark disease

    Science.gov (United States)

    Jeffrey Garnas; David Houston; Matthew Ayres; Celia Evans

    2009-01-01

    Biotic threats to tree growth, survival, or reproduction often arise from interactions among a suite of species, primarily insects and fungi, that function together to varying degrees to defeat host defenses, secure resources, and infect...

  8. Parasite prevalence and community diversity in sympatric and allopatric populations of two woodrat species (Sigmodontinae: Neotoma) in central California.

    Science.gov (United States)

    Bechtel, Molly J; Teglas, Michael B; Murphy, Peter J; Matocq, Marjorie D

    2015-04-01

    Patterns of host-parasite association may vary across the landscape in part because of host and parasite diversity, divergence, local ecology, or interactions among these factors. In central coastal California, we quantified parasite prevalence, infection intensity, and diversity in two sister species of woodrats (Neotoma fuscipes and Neotoma macrotis) where the species co-occur (sympatry) and where each species exists alone (allopatry). In feces from 50 adults we identified seven taxa: the protozoans Eimeria, Giardia, and Cryptosporidium, the nematodes Trichuris, Aspicularis, and Eucoleus, and a cestode in the family Anoplocephalidae. Gastrointestinal parasite infection intensity and diversity were higher in males than in females, a difference that was most pronounced in the more aggressive N. fuscipes. Both species had lower infection intensity in sympatry than in allopatry and in sympatry the two species did not differ in infection intensity in total but did maintain distinct parasite communities. Taken together, our findings suggest that host evolutionary differences, including perhaps species-specific patterns of aggressive behavior, as well as local ecology, influence the likelihood of infection by these endoparasite taxa.

  9. On the origin of a domesticated species: Identifying the parent population of Russian silver foxes (Vulpes vulpes).

    Science.gov (United States)

    Statham, Mark J; Trut, Lyudmila N; Sacks, Ben N; Kharlamova, Anastasiya V; Oskina, Irina N; Gulevich, Rimma G; Johnson, Jennifer L; Temnykh, Svetlana V; Acland, Gregory M; Kukekova, Anna V

    2011-05-01

    The foxes at Novosibirsk, Russia, are the only population of domesticated foxes in the world. These domesticated foxes originated from farm-bred silver foxes (Vulpes vulpes), whose genetic source is unknown. In this study we examined the origin of the domesticated strain of foxes and two other farm-bred fox populations (aggressive and unselected) maintained in Novosibirsk. To identify the phylogenetic origin of these populations we sequenced two regions of mtDNA, cytochrome b and D-loop, from 24 Novosibirsk foxes (8 foxes from each population) and compared them with corresponding sequences of native red foxes from Europe, Asia, Alaska and Western Canada, Eastern Canada, and the Western Mountains of the USA. We identified seven cytochrome b - D-loop haplotypes in Novosibirsk populations, four of which were previously observed in Eastern North America. The three remaining haplotypes differed by one or two base change from the most common haplotype in Eastern Canada. Φ(ST) analysis showed significant differentiation between Novosibirsk populations and red fox populations from all geographic regions except Eastern Canada. No haplotypes of Eurasian origin were identified in the Novosibirsk populations. These results are consistent with historical records indicating that the original breeding stock of farm-bred foxes originated from Prince Edward Island, Canada. Mitochondrial DNA data together with historical records indicate two stages in the selection of domesticated foxes: the first includes captive breeding for ~50 years with unconscious selection for behaviour; the second corresponds to over 50 further years of intensive selection for tame behaviour.

  10. Integrating vital rate variability into perturbation analysis: an evaluation for matrix population