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Sample records for historical population decline

  1. Genetic structure of populations of whale sharks among ocean basins and evidence for their historic rise and recent decline.

    PubMed

    Vignaud, Thomas M; Maynard, Jeffrey A; Leblois, Raphael; Meekan, Mark G; Vázquez-Juárez, Ricardo; Ramírez-Macías, Dení; Pierce, Simon J; Rowat, David; Berumen, Michael L; Beeravolu, Champak; Baksay, Sandra; Planes, Serge

    2014-05-01

    This study presents genetic evidence that whale sharks, Rhincodon typus, are comprised of at least two populations that rarely mix and is the first to document a population expansion. Relatively high genetic structure is found when comparing sharks from the Gulf of Mexico with sharks from the Indo-Pacific. If mixing occurs between the Indian and Atlantic Oceans, it is not sufficient to counter genetic drift. This suggests whale sharks are not all part of a single global metapopulation. The significant population expansion we found was indicated by both microsatellite and mitochondrial DNA. The expansion may have happened during the Holocene, when tropical species could expand their range due to sea-level rise, eliminating dispersal barriers and increasing plankton productivity. However, the historic trend of population increase may have reversed recently. Declines in genetic diversity are found for 6 consecutive years at Ningaloo Reef in Australia. The declines in genetic diversity being seen now in Australia may be due to commercial-scale harvesting of whale sharks and collision with boats in past decades in other countries in the Indo-Pacific. The study findings have implications for models of population connectivity for whale sharks and advocate for continued focus on effective protection of the world's largest fish at multiple spatial scales. © 2014 John Wiley & Sons Ltd.

  2. Population structure and historical demography of South American sea lions provide insights into the catastrophic decline of a marine mammal population

    PubMed Central

    Hoffman, J. I.; Kowalski, G. J.; Klimova, A.; Staniland, I. J.; Baylis, A. M. M.

    2016-01-01

    Understanding the causes of population decline is crucial for conservation management. We therefore used genetic analysis both to provide baseline data on population structure and to evaluate hypotheses for the catastrophic decline of the South American sea lion (Otaria flavescens) at the Falkland Islands (Malvinas) in the South Atlantic. We genotyped 259 animals from 23 colonies across the Falklands at 281 bp of the mitochondrial hypervariable region and 22 microsatellites. A weak signature of population structure was detected, genetic diversity was moderately high in comparison with other pinniped species, and no evidence was found for the decline being associated with a strong demographic bottleneck. By combining our mitochondrial data with published sequences from Argentina, Brazil, Chile and Peru, we also uncovered strong maternally directed population structure across the geographical range of the species. In particular, very few shared haplotypes were found between the Falklands and South America, and this was reflected in correspondingly low migration rate estimates. These findings do not support the prominent hypothesis that the decline was caused by migration to Argentina, where large-scale commercial harvesting operations claimed over half a million animals. Thus, our study not only provides baseline data for conservation management but also reveals the potential for genetic studies to shed light upon long-standing questions pertaining to the history and fate of natural populations. PMID:27493782

  3. Population structure and historical demography of South American sea lions provide insights into the catastrophic decline of a marine mammal population.

    PubMed

    Hoffman, J I; Kowalski, G J; Klimova, A; Eberhart-Phillips, L J; Staniland, I J; Baylis, A M M

    2016-07-01

    Understanding the causes of population decline is crucial for conservation management. We therefore used genetic analysis both to provide baseline data on population structure and to evaluate hypotheses for the catastrophic decline of the South American sea lion (Otaria flavescens) at the Falkland Islands (Malvinas) in the South Atlantic. We genotyped 259 animals from 23 colonies across the Falklands at 281 bp of the mitochondrial hypervariable region and 22 microsatellites. A weak signature of population structure was detected, genetic diversity was moderately high in comparison with other pinniped species, and no evidence was found for the decline being associated with a strong demographic bottleneck. By combining our mitochondrial data with published sequences from Argentina, Brazil, Chile and Peru, we also uncovered strong maternally directed population structure across the geographical range of the species. In particular, very few shared haplotypes were found between the Falklands and South America, and this was reflected in correspondingly low migration rate estimates. These findings do not support the prominent hypothesis that the decline was caused by migration to Argentina, where large-scale commercial harvesting operations claimed over half a million animals. Thus, our study not only provides baseline data for conservation management but also reveals the potential for genetic studies to shed light upon long-standing questions pertaining to the history and fate of natural populations.

  4. Historical amphibian declines and extinctions in Brazil linked to chytridiomycosis.

    PubMed

    Carvalho, Tamilie; Becker, C Guilherme; Toledo, Luís Felipe

    2017-02-08

    The recent increase in emerging fungal diseases is causing unprecedented threats to biodiversity. The origin of spread of the frog-killing fungus Batrachochytrium dendrobatidis (Bd) is a matter of continued debate. To date, the historical amphibian declines in Brazil could not be attributed to chytridiomycosis; the high diversity of hosts coupled with the presence of several Bd lineages predating the reported declines raised the hypothesis that a hypervirulent Bd genotype spread from Brazil to other continents causing the recent global amphibian crisis. We tested for a spatio-temporal overlap between Bd and areas of historical amphibian population declines and extinctions in Brazil. A spatio-temporal convergence between Bd and declines would support the hypothesis that Brazilian amphibians were not adapted to Bd prior to the reported declines, thus weakening the hypothesis that Brazil was the global origin of Bd emergence. Alternatively, a lack of spatio-temporal association between Bd and frog declines would indicate an evolution of host resistance in Brazilian frogs predating Bd's global emergence, further supporting Brazil as the potential origin of the Bd panzootic. Here, we Bd-screened over 30 000 museum-preserved tadpoles collected in Brazil between 1930 and 2015 and overlaid spatio-temporal Bd data with areas of historical amphibian declines. We detected an increase in the proportion of Bd-infected tadpoles during the peak of amphibian declines (1979-1987). We also found that clusters of Bd-positive samples spatio-temporally overlapped with most records of amphibian declines in Brazil's Atlantic Forest. Our findings indicate that Brazil is post epizootic for chytridiomycosis and provide another piece to the puzzle to explain the origin of Bd globally. © 2017 The Author(s).

  5. Predicting how populations decline to extinction

    PubMed Central

    Collen, Ben; McRae, Louise; Deinet, Stefanie; De Palma, Adriana; Carranza, Tharsila; Cooper, Natalie; Loh, Jonathan; Baillie, Jonathan E. M.

    2011-01-01

    Global species extinction typically represents the endpoint in a long sequence of population declines and local extinctions. In comparative studies of extinction risk of contemporary mammalian species, there appear to be some universal traits that may predispose taxa to an elevated risk of extinction. In local population-level studies, there are limited insights into the process of population decline and extinction. Moreover, there is still little appreciation of how local processes scale up to global patterns. Advancing the understanding of factors which predispose populations to rapid declines will benefit proactive conservation and may allow us to target at-risk populations as well as at-risk species. Here, we take mammalian population trend data from the largest repository of population abundance trends, and combine it with the PanTHERIA database on mammal traits to answer the question: what factors can be used to predict decline in mammalian abundance? We find in general that environmental variables are better determinants of cross-species population-level decline than intrinsic biological traits. For effective conservation, we must not only describe which species are at risk and why, but also prescribe ways to counteract this. PMID:21807738

  6. Emerging infectious diseases and amphibian population declines.

    PubMed Central

    Daszak, P.; Berger, L.; Cunningham, A. A.; Hyatt, A. D.; Green, D. E.; Speare, R.

    1999-01-01

    We review recent research on the pathology, ecology, and biogeography of two emerging infectious wildlife diseases, chytridiomycosis and ranaviral disease, in the context of host-parasite population biology. We examine the role of these diseases in the global decline of amphibian populations and propose hypotheses for the origins and impact of these panzootics. Finally, we discuss emerging infectious diseases as a global threat to wildlife populations. PMID:10603206

  7. Coin hoards speak of population declines in Ancient Rome

    PubMed Central

    Turchin, Peter; Scheidel, Walter

    2009-01-01

    In times of violence, people tend to hide their valuables, which are later recovered unless the owners had been killed or driven away. Thus, the temporal distribution of unrecovered coin hoards is an excellent proxy for the intensity of internal warfare. We use this relationship to resolve a long-standing controversy in Roman history. Depending on who was counted in the early Imperial censuses (adult males or the entire citizenry including women and minors), the Roman citizen population of Italy either declined, or more than doubled, during the first century BCE. This period was characterized by a series of civil wars, and historical evidence indicates that high levels of sociopolitical instability are associated with demographic contractions. We fitted a simple model quantifying the effect of instability (proxied by hoard frequency) on population dynamics to the data before 100 BCE. The model predicts declining population after 100 BCE. This suggests that the vigorous growth scenario is highly implausible. PMID:19805043

  8. Coin hoards speak of population declines in Ancient Rome.

    PubMed

    Turchin, Peter; Scheidel, Walter

    2009-10-13

    In times of violence, people tend to hide their valuables, which are later recovered unless the owners had been killed or driven away. Thus, the temporal distribution of unrecovered coin hoards is an excellent proxy for the intensity of internal warfare. We use this relationship to resolve a long-standing controversy in Roman history. Depending on who was counted in the early Imperial censuses (adult males or the entire citizenry including women and minors), the Roman citizen population of Italy either declined, or more than doubled, during the first century BCE. This period was characterized by a series of civil wars, and historical evidence indicates that high levels of sociopolitical instability are associated with demographic contractions. We fitted a simple model quantifying the effect of instability (proxied by hoard frequency) on population dynamics to the data before 100 BCE. The model predicts declining population after 100 BCE. This suggests that the vigorous growth scenario is highly implausible.

  9. Migratory diversity predicts population declines in birds.

    PubMed

    Gilroy, James J; Gill, Jennifer A; Butchart, Stuart H M; Jones, Victoria R; Franco, Aldina M A

    2016-03-01

    Declines in migratory species are a pressing concern worldwide, but the mechanisms underpinning these declines are not fully understood. We hypothesised that species with greater within-population variability in migratory movements and destinations, here termed 'migratory diversity', might be more resilient to environmental change. To test this, we related map-based metrics of migratory diversity to recent population trends for 340 European breeding birds. Species that occupy larger non-breeding ranges relative to breeding, a characteristic we term 'migratory dispersion', were less likely to be declining than those with more restricted non-breeding ranges. Species with partial migration strategies (i.e. overlapping breeding and non-breeding ranges) were also less likely to be declining than full migrants or full residents, an effect that was independent of migration distance. Recent rates of advancement in Europe-wide spring arrival date were greater for partial migrants than full migrants, suggesting that migratory diversity may also help facilitate species responses to climate change. © 2016 John Wiley & Sons Ltd/CNRS.

  10. Fertility decline in Punjab, India: parallels with historical Europe.

    PubMed

    Gupta, M D

    1995-11-01

    Two interesting features emerge from this study of fertility behaviour in Punjab. First, it brings out the common features of peasant life and demographic behaviour found in this developing-country setting and in historical Europe. As in much of Europe, marriage was regulated to adjust to the availability of land and other resources. It is interesting to note that the operation of this 'nuptiality valve' was quite consistent with a system of joint families and partible inheritance. Secondly, the findings suggest that we need to re-define what we understand to be the features of socio-economic development which are crucial for fertility decline. Fertility began to decline steadily in this part of Punjab as early as 1940, at a time when the society was overwhelmingly agrarian, illiterate, and infant mortality was high with no access to modern contraceptive technology, as in historical Europe. The onset of the decline was brought about by development interventions which stabilized fluctuations in crop yields and mortality, thus radically improving stability of people's expectations. This study also points out the inapplicability of Mamdani's theories of fertility behaviour to the people he studies.

  11. The Population Decline and Extinction of Darwin’s Frogs

    PubMed Central

    Soto-Azat, Claudio; Valenzuela-Sánchez, Andrés; Collen, Ben; Rowcliffe, J. Marcus; Veloso, Alberto; Cunningham, Andrew A.

    2013-01-01

    Darwin’s frogs (Rhinoderma darwinii and R. rufum) are two species of mouth-brooding frogs from Chile and Argentina. Here, we present evidence on the extent of declines, current distribution and conservation status of Rhinoderma spp.; including information on abundance, habitat and threats to extant Darwin’s frog populations. All known archived Rhinoderma specimens were examined in museums in North America, Europe and South America. Extensive surveys were carried out throughout the historical ranges of R. rufum and R. darwinii from 2008 to 2012. Literature review and location data of 2,244 archived specimens were used to develop historical distribution maps for Rhinoderma spp. Based on records of sightings, optimal linear estimation was used to estimate whether R. rufum can be considered extinct. No extant R. rufum was found and our modelling inferred that this species became extinct in 1982 (95% CI, 1980–2000). Rhinoderma darwinii was found in 36 sites. All populations were within native forest and abundance was highest in Chiloé Island, when compared with Coast, Andes and South populations. Estimated population size and density (five populations) averaged 33.2 frogs/population (range, 10.2–56.3) and 14.9 frogs/100 m2 (range, 5.3–74.1), respectively. Our results provide further evidence that R. rufum is extinct and indicate that R. darwinii has declined to a much greater degree than previously recognised. Although this species can still be found across a large part of its historical range, remaining populations are small and severely fragmented. Conservation efforts for R. darwinii should be stepped up and the species re-classified as Endangered. PMID:23776705

  12. Historical decline in coral reef growth after the Panama Canal.

    PubMed

    Guzman, Hector M; Cipriani, Roberto; Jackson, Jeremy B C

    2008-07-01

    The Panama Canal is near its vessel size and tonnage handling capacity, and Panamanians have decided to expand it. The expansion of the Canal may consider the historical long-lasting impacts on marine coastal habitats particularly on sensitive coral reefs. These potential impacts were discussed during the national referendum as were other equally important issues, such as its effects on forests, watersheds, and water supply. Coral growth rates provide a direct measure of coral fitness and past environmental conditions comparable to analyses of tree rings. We examined stable isotopes, metal geochemical tracers, and growth rates on a century-long (1880-1989) chronology based on 77 cores of the dominant reef-building coral Siderastrea siderea collected near the Caribbean entrance to the canal. Our results showed a gradual decline in coral growth unrelated to changes in sea surface temperature but linked to runoff and sedimentation to coastal areas resulting from the construction and operation of the Panama Canal.

  13. Dynamic distributions and population declines of Golden-winged Warblers

    USGS Publications Warehouse

    Rosenberg, Kenneth V.; Will, Tom; Buehler, David A.; Barker Swarthout, Sara; Thogmartin, Wayne E.; Chandler, Richard

    2016-01-01

    hybrid zone, but the future of northern populations in the Great Lakes states and Canada (where >80% of the species occurs at present) is highly uncertain because of continued northward expansion of Blue-winged Warblers and hybridization. A second, now-disjunct band of Golden-winged Warbler populations exists in the Appalachian Mountains from southeastern New York to northern Georgia, surrounded at lower elevations by Blue-winged Warblers. Important concentrations of Golden-winged Warblers persist in the Allegheny Mountains region of West Virginia, the Cumberland Mountains in Tennessee, Blue Ridge Mountains of western North Carolina, Allegheny Plateau and Pocono Mountains in Pennsylvania, and in the Hudson Highlands of southern New York. These high-elevation Appalachian populations have escaped contact with Blue-winged Warblers until very recently and represent important refugia for conservation and management; other Appalachian populations are rapidly declining. In addition, based on historical records and standardized surveys across the wintering grounds, we identified three regions of concentration: highlands and Caribbean slopes from Guatemala and Belize to northwestern Nicaragua; middle elevations (both slopes) in Costa Rica and western Panama; and in an arc of the northern Andes from central Colombia to northern Venezuela. It is possible that the winter range has been shifting towards the northwest in recent decades, paralleling shifts in the breeding distribution. Future conservation efforts for Golden-winged Warbler need to include close monitoring of the dynamic phenotypic and genetic distributional shifts, and may need to consider the “winged warbler” complex together as a highly adaptable evolutionary unit.

  14. Microsatellite Analysis of Museum Specimens Reveals Historical Differences in Genetic Diversity between Declining and More Stable Bombus Species

    PubMed Central

    Maebe, Kevin; Meeus, Ivan; Ganne, Maarten; De Meulemeester, Thibaut; Biesmeijer, Koos; Smagghe, Guy

    2015-01-01

    Worldwide most pollinators, e.g. bumblebees, are undergoing global declines. Loss of genetic diversity can play an essential role in these observed declines. In this paper, we investigated the level of genetic diversity of seven declining Bombus species and four more stable species with the use of microsatellite loci. Hereto we genotyped a unique collection of museum specimens. Specimens were collected between 1918 and 1926, in 6 provinces of the Netherlands which allowed us to make interspecific comparisons of genetic diversity. For the stable species B. pascuorum, we also selected populations from two additional time periods: 1949–1955 and 1975–1990. The genetic diversity and population structure in B. pascuorum remained constant over the three time periods. However, populations of declining bumblebee species showed a significantly lower genetic diversity than co-occurring stable species before their major declines. This historical difference indicates that the repeatedly observed reduced genetic diversity in recent populations of declining bumblebee species is not caused solely by the decline itself. The historically low genetic diversity in the declined species may be due to the fact that these species were already rare, making them more vulnerable to the major drivers of bumblebee decline. PMID:26061732

  15. Microsatellite Analysis of Museum Specimens Reveals Historical Differences in Genetic Diversity between Declining and More Stable Bombus Species.

    PubMed

    Maebe, Kevin; Meeus, Ivan; Ganne, Maarten; De Meulemeester, Thibaut; Biesmeijer, Koos; Smagghe, Guy

    2015-01-01

    Worldwide most pollinators, e.g. bumblebees, are undergoing global declines. Loss of genetic diversity can play an essential role in these observed declines. In this paper, we investigated the level of genetic diversity of seven declining Bombus species and four more stable species with the use of microsatellite loci. Hereto we genotyped a unique collection of museum specimens. Specimens were collected between 1918 and 1926, in 6 provinces of the Netherlands which allowed us to make interspecific comparisons of genetic diversity. For the stable species B. pascuorum, we also selected populations from two additional time periods: 1949-1955 and 1975-1990. The genetic diversity and population structure in B. pascuorum remained constant over the three time periods. However, populations of declining bumblebee species showed a significantly lower genetic diversity than co-occurring stable species before their major declines. This historical difference indicates that the repeatedly observed reduced genetic diversity in recent populations of declining bumblebee species is not caused solely by the decline itself. The historically low genetic diversity in the declined species may be due to the fact that these species were already rare, making them more vulnerable to the major drivers of bumblebee decline.

  16. Prehistorical and historical declines in Caribbean coral reef accretion rates driven by loss of parrotfish

    NASA Astrophysics Data System (ADS)

    Cramer, Katie L.; O'Dea, Aaron; Clark, Tara R.; Zhao, Jian-Xin; Norris, Richard D.

    2017-01-01

    Caribbean coral reefs have transformed into algal-dominated habitats over recent decades, but the mechanisms of change are unresolved due to a lack of quantitative ecological data before large-scale human impacts. To understand the role of reduced herbivory in recent coral declines, we produce a high-resolution 3,000 year record of reef accretion rate and herbivore (parrotfish and urchin) abundance from the analysis of sediments and fish, coral and urchin subfossils within cores from Caribbean Panama. At each site, declines in accretion rates and parrotfish abundance were initiated in the prehistorical or historical period. Statistical tests of direct cause and effect relationships using convergent cross mapping reveal that accretion rates are driven by parrotfish abundance (but not vice versa) but are not affected by total urchin abundance. These results confirm the critical role of parrotfish in maintaining coral-dominated reef habitat and the urgent need for restoration of parrotfish populations to enable reef persistence.

  17. Prehistorical and historical declines in Caribbean coral reef accretion rates driven by loss of parrotfish

    PubMed Central

    Cramer, Katie L.; O'Dea, Aaron; Clark, Tara R.; Zhao, Jian-xin; Norris, Richard D.

    2017-01-01

    Caribbean coral reefs have transformed into algal-dominated habitats over recent decades, but the mechanisms of change are unresolved due to a lack of quantitative ecological data before large-scale human impacts. To understand the role of reduced herbivory in recent coral declines, we produce a high-resolution 3,000 year record of reef accretion rate and herbivore (parrotfish and urchin) abundance from the analysis of sediments and fish, coral and urchin subfossils within cores from Caribbean Panama. At each site, declines in accretion rates and parrotfish abundance were initiated in the prehistorical or historical period. Statistical tests of direct cause and effect relationships using convergent cross mapping reveal that accretion rates are driven by parrotfish abundance (but not vice versa) but are not affected by total urchin abundance. These results confirm the critical role of parrotfish in maintaining coral-dominated reef habitat and the urgent need for restoration of parrotfish populations to enable reef persistence. PMID:28112169

  18. Prehistorical and historical declines in Caribbean coral reef accretion rates driven by loss of parrotfish.

    PubMed

    Cramer, Katie L; O'Dea, Aaron; Clark, Tara R; Zhao, Jian-Xin; Norris, Richard D

    2017-01-23

    Caribbean coral reefs have transformed into algal-dominated habitats over recent decades, but the mechanisms of change are unresolved due to a lack of quantitative ecological data before large-scale human impacts. To understand the role of reduced herbivory in recent coral declines, we produce a high-resolution 3,000 year record of reef accretion rate and herbivore (parrotfish and urchin) abundance from the analysis of sediments and fish, coral and urchin subfossils within cores from Caribbean Panama. At each site, declines in accretion rates and parrotfish abundance were initiated in the prehistorical or historical period. Statistical tests of direct cause and effect relationships using convergent cross mapping reveal that accretion rates are driven by parrotfish abundance (but not vice versa) but are not affected by total urchin abundance. These results confirm the critical role of parrotfish in maintaining coral-dominated reef habitat and the urgent need for restoration of parrotfish populations to enable reef persistence.

  19. Hyperstability masks declines in bumphead parrotfish ( Bolbometopon muricatum) populations

    NASA Astrophysics Data System (ADS)

    Hamilton, Richard J.; Almany, Glenn R.; Stevens, Don; Bode, Michael; Pita, John; Peterson, Nate A.; Choat, J. Howard

    2016-09-01

    Bolbometopon muricatum, the largest species of parrotfish, is a functionally important species that is characterised by the formation of aggregations for foraging, reproductive, and sleeping behaviours. Aggregations are restricted to shallow reef habitats, the locations of which are often known to local fishers. Bolbometopon muricatum fisheries are therefore vulnerable to overfishing and are likely to exhibit hyperstability, the maintenance of high catch per unit effort (CPUE) while population abundance declines. In this study, we provide a clear demonstration of hyperstable dynamics in a commercial B. muricatum fishery in Isabel Province, Solomon Islands. Initially, we used participatory mapping to demarcate the Kia fishing grounds into nine zones that had experienced different historic levels of fishing pressure. We then conducted comprehensive underwater visual census (UVC) and CPUE surveys across these zones over a 21-month period in 2012-2013. The individual sites for replicate UVC surveys were selected using a generalised random tessellation stratified variable probability design, while CPUE surveys involved trained provincial fisheries officers and local spearfishers. A comparison of fishery-independent abundance data and fishery-dependent CPUE data indicate extreme hyperstability, with CPUE maintained as B. muricatum abundance declines towards zero. Hyperstability may explain the sudden collapses of many B. muricatum spear fisheries across the Pacific and highlights the limitations of using data-poor fisheries assessment methods to evaluate the status of commercially valuable coral reef fishes that form predicable aggregations.

  20. Estimation of population growth or decline in genetically monitored populations.

    PubMed Central

    Beaumont, Mark A

    2003-01-01

    This article introduces a new general method for genealogical inference that samples independent genealogical histories using importance sampling (IS) and then samples other parameters with Markov chain Monte Carlo (MCMC). It is then possible to more easily utilize the advantages of importance sampling in a fully Bayesian framework. The method is applied to the problem of estimating recent changes in effective population size from temporally spaced gene frequency data. The method gives the posterior distribution of effective population size at the time of the oldest sample and at the time of the most recent sample, assuming a model of exponential growth or decline during the interval. The effect of changes in number of alleles, number of loci, and sample size on the accuracy of the method is described using test simulations, and it is concluded that these have an approximately equivalent effect. The method is used on three example data sets and problems in interpreting the posterior densities are highlighted and discussed. PMID:12871921

  1. When can the cause of a population decline be determined?

    USGS Publications Warehouse

    Hefley, Trevor J.; Hooten, Mevin B.; Drake, John M.; Russell, Robin E.; Walsh, Daniel P.

    2016-01-01

    Inferring the factors responsible for declines in abundance is a prerequisite to preventing the extinction of wild populations. Many of the policies and programmes intended to prevent extinctions operate on the assumption that the factors driving the decline of a population can be determined. Exogenous factors that cause declines in abundance can be statistically confounded with endogenous factors such as density dependence. To demonstrate the potential for confounding, we used an experiment where replicated populations were driven to extinction by gradually manipulating habitat quality. In many of the replicated populations, habitat quality and density dependence were confounded, which obscured causal inference. Our results show that confounding is likely to occur when the exogenous factors that are driving the decline change gradually over time. Our study has direct implications for wild populations, because many factors that could drive a population to extinction change gradually through time.

  2. Survival rates of female white-tailed deer on an industrial forest following a decline in population density

    Treesearch

    Shawn M. Crimmins; John W. Edwards; Patrick D. Keyser; James M. Crum; W. Mark Ford; Brad F. Miller; Tyler A. Campbell; Karl V. Miller

    2013-01-01

    With white-tailed deer (Odocoileus virginianus) populations at historically high levels throughout many North American forests, many current management activities are aimed at reducing deer populations. However, very little information exists on the ecology of low-density white-tailed deer populations or populations that have declined in density. We...

  3. AMPHIBIAN DECLINE, ULTRAVIOLET RADIATION AND LOCAL POPULATION ADAPTATION

    EPA Science Inventory

    Amphibian population declines have been noted on both local and global scales. Causes for these declines are unknown although many hypotheses have been offered. In areas adjacent to human development, loss of habitat is a fairly well accepted cause. However in isolated, seemingl...

  4. AMPHIBIAN DECLINE, ULTRAVIOLET RADIATION AND LOCAL POPULATION ADAPTATION

    EPA Science Inventory

    Amphibian population declines have been noted on both local and global scales. Causes for these declines are unknown although many hypotheses have been offered. In areas adjacent to human development, loss of habitat is a fairly well accepted cause. However in isolated, seemingl...

  5. DECLINE IN LAKE ONTARIO POPULATIONS OF BENTHIC MACROINVERTEBRATES

    EPA Science Inventory

    Surveys of benthic macroinvertebrates conducted in Lake Ontario during 1994 and 1997 revealed declines in populations of three major groups of organisms: oligochaetes, sphariids, and Diporeia spp. (Amphipoda), with the most drastic reductions occurring in the latter. Based on phy...

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

    EPA Science Inventory

    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 ...

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

    EPA Science Inventory

    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 ...

  8. Minimal models of growth and decline of microbial populations.

    PubMed

    Juška, Alfonsas

    2011-01-21

    Dynamics of growth and decline of microbial populations were analysed and respective models were developed in this investigation. Analysis of the dynamics was based on general considerations concerning the main properties of microorganisms and their interactions with the environment which was supposed to be affected by the activity of the population. Those considerations were expressed mathematically by differential equations or systems of the equations containing minimal sets of parameters characterizing those properties. It has been found that: (1) the factors leading to the decline of the population have to be considered separately, namely, accumulation of metabolites (toxins) in the medium and the exhaustion of resources; the latter have to be separated again into renewable ('building materials') and non-renewable (sources of energy); (2) decline of the population is caused by the exhaustion of sources of energy but no decline is predicted by the model because of the exhaustion of renewable resources; (3) the model determined by the accumulation of metabolites (toxins) in the medium does not suggest the existence of a separate 'stationary phase'; (4) in the model determined by the exhaustion of energy resources the 'stationary' and 'decline' phases are quite discernible; and (5) there is no symmetry in microbial population dynamics, the decline being slower than the rise. Mathematical models are expected to be useful in getting insight into the process of control of the dynamics of microbial populations. The models are in agreement with the experimental data.

  9. Decline of disjunct green salamander (Aneides aeneus) populations in the southern appalachians

    USGS Publications Warehouse

    Corser, J.D.

    2001-01-01

    Coincident with other amphibians around the world Aneides aeneus, a terrestrial plethodontid salamander, suffered a population collapse in a disjunct portion of its range in the mid-late 1970s. Long-term monitoring of seven historical green salamander populations throughout the 1990s showed a 98% decline in relative abundance since 1970. Three out of six populations first discovered in 1991 also crashed in 1996-1997. The synchronized suddenness of the declines, their region-wide impact, and effects on both small and larger populations, suggest the role of a novel agent of mortality beginning in the mid-late 1970s. Acting alone, but more likely in concert, habitat loss, overcollecting, epidemic disease and climate change could account for this region-wide decline.

  10. Sea otter population declines in the Aleutian Archipelago

    USGS Publications Warehouse

    Doroff, Angela; Estes, James A.; Tinker, M. Tim; Burn, Douglas M.; Evans, Thomas J.

    2003-01-01

    Sea otter (Enhydra lutris) populations were exploited to near extinction and began to recover after the cessation of commercial hunting in 1911. Remnant colonies of sea otters in the Aleutian archipelago were among the first to recover; they continued to increase through the 1980s but declined abruptly during the 1990s. We conducted an aerial survey of the Aleutian archipelago in 2000 and compared results with similar surveys conducted in 1965 and 1992. The number of sea otters counted decreased by 75% between 1965 and 2000; 88% for islands at equilibrial density in 1965. The population decline likely began in the mid-1980s and declined at a rate of 17.5%/year in the 1990s. The minimal population estimate was 8,742 sea otters in 2000. The population declined to a uniformly low density in the archipelago, suggesting a common and geographically widespread cause. These data are in general agreement with the hypothesis of increased predation on sea otters. These data chronicle one of the most widespread and precipitous population declines for a mammalian carnivore in recorded history.

  11. Biogeography and decline of rare plants in New England: historical evidence and contemporary monitoring.

    PubMed

    Farnsworth, Elizabeth J; Ogurcak, Danielle E

    2006-08-01

    Detecting range shifts and contractions is critical for determining the conservation priority of rare and declining taxa. However, data on rare species occurrences frequently lack precise information on locations and habitats and may present a biased picture of biogeographic distributions and presumed habitat preferences. Herbarium or museum specimen data, which otherwise could be useful proxies for detecting temporal trends and spatial patterns in species distributions, pose particular challenges. Using data from herbaria and Natural Heritage Programs on numbers of occurrences within individual municipalities (towns, cities, or townships), we quantified temporal changes in the estimated distributions of 110 rare plant species in the six New England (USA) states. We used the partial Solow equation and a nonparametric test to estimate the probability of observing multiple absences (gaps in the collection record) if a given population was actually still extant. Bayes' Theorem was used to estimate the probability that occurrences were misclassified as extinct. Using the probabilities obtained from these three methods, we eliminated taxa with high probabilities of pseudo-absence (that would yield an inaccurate profile of species distributions), narrowing the set for final analysis to 71 taxa. We then expressed occurrences as centroids of town polygons and estimated current and historical range areas (extents of occurrence as defined by alpha-hulls inscribing occurrences), mean distances between occurrences, and latitudinal and longitudinal range boundaries. Using a geographic information system, we modeled first, second, and third circular standard deviational polygons around the mean center of the historical range. Examining the distribution of current occurrences within each standard deviational polygon, we asked whether ranges were collapsing to a center, expanding, fragmenting, or contracting to a margin of the former range. Extant ranges of the species were, on

  12. The historical decline of tobacco smoking among United States physicians: 1949–1984

    PubMed Central

    Smith, Derek R

    2008-01-01

    Background Tobacco use became an ingrained habit in the United States (US) following the First World War and a large proportion of physicians, similar to the general population, were smokers. The period from 1949 to 1984 was a pivotal era of change however, as the medical profession, like the society it served, became increasingly aware of the dangers that tobacco incurred for health. Methods An extensive review targeted all manuscripts published in academic journals between 1949 and 1984 that related to tobacco smoking among US physicians. The study was undertaken in 2007–08 with an internet search of relevant medical databases, after which time the reference lists of manuscripts were also examined to find additional articles. Results A total of 57 manuscripts met the inclusion criteria. From a research perspective, the methodology and coverage of smoking surveys ranged from detailed national investigations, to local medical association surveys, and journal readership questionnaires. From a historical perspective, it can be seen that by the 1950s many US physicians had begun questioning the safety of tobacco products, and by the 1960s and 1970s, this had resulted in a continuous decline in tobacco use. By the 1980s, few US physicians were still smoking, and many of their younger demographic had probably never smoked at all. Conclusion Although the quality and coverage of historical surveys varied over time, a review of their main results indicates a clear and consistent decline in tobacco use among US physicians between 1949 and 1984. Much can be learned from this pivotal era of public health, where the importance of scientific knowledge, professional leadership and social responsibility helped set positive examples in the fight against tobacco. PMID:18822167

  13. Population decline and plague in late medieval Norway.

    PubMed

    Brothen, J A

    1996-01-01

    Norwegian scholars have engaged in considerable research over the last half century in an attempt to assess the impact of the Black Plague of 1349 on population and society in Norway. Evidence has been put forward relating the incidence of plague to a continuance of population decline over the two centuries following its initial introduction. Estimates of population decline in Norway between 1350 and 1550 indicate a reduction by as much as 65%. Two directions of study have emerged, one concentrating on land abandonment known as the "Ødegard Project." The other is represented by the recent works of Ole Jørgen Benedictow presenting epidemiological and osteo-archaeological research. An examination of the available literature raises questions concerning the degree to which plague, and its recurrence, directly affected population decline in Norway during the Late Middle Ages. While evidence of the virulence of the plague and the degree of farm abandonment is compelling, a direct relationship to population decline may not be as great as implied by the research. Other explanatory factors, especially social and economic responses to plague, have been given limited attention.

  14. Pesticides and amphibian population declines in California, USA

    USGS Publications Warehouse

    Sparling, Donald W.; Fellers, Gary M.; McConnell, Laura L.

    2001-01-01

    Several species of anuran amphibians have undergone drastic population declines in the western United States over the last 10 to 15 years. In California, the most severe declines are in the Sierra Mountains east of the Central Valley and downwind of the intensely agricultural San Joaquin Valley. In contrast, coastal and more northern populations across from the less agrarian Sacramento Valley are stable or declining less precipitously. In this article, we provide evidence that pesticides are instrumental in declines of these species. Using Hyla regilla as a sentinel species, we found that cholinesterase (ChE) activity in tadpoles was depressed in mountainous areas east of the Central Valley compared with sites along the coast or north of the Valley. Cholinesterase was also lower in areas where ranid population status was poor or moderate compared with areas with good ranid status. Up to 50% of the sampled population in areas with reduced ChE had detectable organophosphorus residues, with concentrations as high as 190 ppb wet weight. In addition, up to 86% of some populations had measurable endosulfan concentrations and 40% had detectable 4,4'- dichlorodiphenyldichloroethylene, 4,4'-DDT, and 2,4'-DDT residues.

  15. Declining populations of the fingernail clam Musculium transversum in the upper Mississippi River

    USGS Publications Warehouse

    Wilson, D.M.; Naimo, T.J.; Weiner, J.G.; Anderson, R.V.; Sandheinrich, M.B.; Sparks, R.E.

    1995-01-01

    We examined recent temporal trends in the abundance of fingernail clams Musculium transversum (formerly Sphaerium transversum) in the upper Mississippi River. Historical data on densities of fingernail clams were obtained from regional scientists and published literature. We also sampled benthos in six navigation pools in summer 1991, finding very few fingernail clams. The combined data set, including historical data and sampling results, extended from 1973 to 1992 and was sufficient to statistically evaluate trends in densities of fingernail clams in eight pools. Populations of fingernail clams declined significantly in five of the eight pools examined (Pools 2, 5, 7, 9, and 19), which spanned a 700-km reach of river from St. Paul, Minnesota, to Keokuk, Iowa. Densities in Pool 19, which had the longest historical record on fingernail clam abundance, averaged 30 000 m super(-2) in 1985 and progressively declined to zero in 1990. Combined data from all eight pools showed a significant decline in abundance of fingernail clams. An evaluation of potential causal factors led us to hypothesize that the population declines in Pools 2 to 9 were linked to point-source pollution rather than to dredging activity or commercial navigation traffic. In Pool 19, the declines of fingernail clams may have resulted from low-flow conditions during drought periods, but the causal mechanisms by which low flow influences fingernail clam abundance are unclear. The decrease in fingernail clam populations may adversely affect certain fish and wildlife, such as migrating lesser scaup Aythya affinis, which feed heavily on the small mollusk. Moreover, the decreases in populations of this pollution-sensitive mollusk may signal a large-scale deterioration in the health of this riverine ecosystem.

  16. Historical and contemporary DNA indicate fisher decline and isolation occurred prior to the European settlement of California.

    PubMed

    Tucker, Jody M; Schwartz, Michael K; Truex, Richard L; Pilgrim, Kristine L; Allendorf, Fred W

    2012-01-01

    Establishing if species contractions were the result of natural phenomena or human induced landscape changes is essential for managing natural populations. Fishers (Martes pennanti) in California occur in two geographically and genetically isolated populations in the northwestern mountains and southern Sierra Nevada. Their isolation is hypothesized to have resulted from a decline in abundance and distribution associated with European settlement in the 1800s. However, there is little evidence to establish that fisher occupied the area between the two extant populations at that time. We analyzed 10 microsatellite loci from 275 contemporary and 21 historical fisher samples (1880-1920) to evaluate the demographic history of fisher in California. We did not find any evidence of a recent (post-European) bottleneck in the northwestern population. In the southern Sierra Nevada, genetic subdivision within the population strongly influenced bottleneck tests. After accounting for genetic subdivision, we found a bottleneck signal only in the northern and central portions of the southern Sierra Nevada, indicating that the southernmost tip of these mountains may have acted as a refugium for fisher during the anthropogenic changes of the late 19(th) and early 20(th) centuries. Using a coalescent-based Bayesian analysis, we detected a 90% decline in effective population size and dated the time of decline to over a thousand years ago. We hypothesize that fisher distribution in California contracted to the two current population areas pre-European settlement, and that portions of the southern Sierra Nevada subsequently experienced another more recent bottleneck post-European settlement.

  17. Pesticides and Population Declines of California Alpine Frogs

    EPA Science Inventory

    Airborne pesticides from the Central Valley of California have been implicated as a cause for population declines of several amphibian species, with the strongest evidence for the mountain yellow-legged frog complex (Rana muscosa and R. sierrae) in the Sierra Nevada. We measured ...

  18. Pesticides and Population Declines of California Alpine Frogs

    EPA Science Inventory

    Airborne pesticides from the Central Valley of California have been implicated as a cause for population declines of several amphibian species, with the strongest evidence for the mountain yellow-legged frog complex (Rana muscosa and R. sierrae) in the Sierra Nevada. We measured ...

  19. Dropping dead: causes and consequences of vulture population declines worldwide.

    PubMed

    Ogada, Darcy L; Keesing, Felicia; Virani, Munir Z

    2012-02-01

    Vultures are nature's most successful scavengers, and they provide an array of ecological, economic, and cultural services. As the only known obligate scavengers, vultures are uniquely adapted to a scavenging lifestyle. Vultures' unique adaptations include soaring flight, keen eyesight, and extremely low pH levels in their stomachs. Presently, 14 of 23 (61%) vulture species worldwide are threatened with extinction, and the most rapid declines have occurred in the vulture-rich regions of Asia and Africa. The reasons for the population declines are varied, but poisoning or human persecution, or both, feature in the list of nearly every declining species. Deliberate poisoning of carnivores is likely the most widespread cause of vulture poisoning. In Asia, Gyps vultures have declined by >95% due to poisoning by the veterinary drug diclofenac, which was banned by regional governments in 2006. Human persecution of vultures has occurred for centuries, and shooting and deliberate poisoning are the most widely practiced activities. Ecological consequences of vulture declines include changes in community composition of scavengers at carcasses and an increased potential for disease transmission between mammalian scavengers at carcasses. There have been cultural and economic costs of vulture declines as well, particularly in Asia. In the wake of catastrophic vulture declines in Asia, regional governments, the international scientific and donor communities, and the media have given the crisis substantial attention. Even though the Asian vulture crisis focused attention on the plight of vultures worldwide, the situation for African vultures has received relatively little attention especially given the similar levels of population decline. While the Asian crisis has been largely linked to poisoning by diclofenac, vulture population declines in Africa have numerous causes, which have made conserving existing populations more difficult. And in Africa there has been little

  20. Critical Decline of the Eastern Caribbean Sperm Whale Population

    PubMed Central

    Whitehead, Hal

    2016-01-01

    Sperm whale (Physeter macrocephalus) populations were expected to rebuild following the end of commercial whaling. We document the decline of the population in the eastern Caribbean by tracing demographic changes of well-studied social units. We address hypotheses that, over a ten-year period of dedicated effort (2005–2015), unit size, numbers of calves and/or calving rates have each declined. Across 16 units, the number of adults decreased in 12 units, increased in two, and showed no change in two. The number of adults per unit decreased at -0.195 individuals/yr (95% CI: -0.080 to -0.310; P = 0.001). The number of calves also declined, but the decline was not significant. This negative trend of -4.5% per year in unit size started in about 2010, with numbers being fairly stable until then. There are several natural and anthropogenic threats, but no well-substantiated cause for the decline. PMID:27706153

  1. Human Population Decline in North America during the Younger Dryas

    NASA Astrophysics Data System (ADS)

    Anderson, D. G.; Goodyear, A. C.; Stafford, T. W., Jr.; Kennett, J.; West, A.

    2009-12-01

    There is ongoing debate about a possible human population decline or contraction at the onset of the Younger Dryas (YD) at 12.9 ka. We used two methods to test whether the YD affected human population levels: (1) frequency analyses of Paleoindian projectile points, and (2) summed probability analyses of radiocarbon (14C) dates. The results suggest that a significant decline or reorganization of human populations occurred at 12.9 ka, continued through the initial centuries of the YD chronozone, then rebounded by the end of the YD. FREQUENCY ANALYSES: This method employed projectile point data from the Paleoindian Database of the Americas (PIDBA, http://pidba.utk.edu). We tallied diagnostic projectile points and obtained larger totals for Clovis points than for immediately post-Clovis points, which share an instrument-assisted fluting technique, typically using pressure or indirect percussion. Gainey, Vail, Debert, Redstone, and Cumberland point-styles utilized this method and are comparable to the Folsom style. For the SE U.S., the ratio of Clovis points (n=1993) to post-Clovis points (n=947) reveals a point decline of 52%. For the Great Plains, a comparison of Clovis and fluted points (n=4020) to Folsom points (n=2527) shows a point decline of 37%, which may translate into a population contraction of similar magnitude. In addition, eight major Clovis lithic quarry sites in the SE U.S. exhibit little to no evidence for immediate post-Clovis occupations, implying a major population decline. SUMMED PROBABILITIES: This method involved calibrating relevant 14C dates and combining the probabilities, after which major peaks and troughs in the trends are assumed to reflect changes in human demographics. Using 14C dates from Buchanan et al. (2008), we analyzed multiple regions, including the Southeast and Great Plains. Contrary to Buchanan et al., we found an abrupt, statistically significant decline at 12.9 ka, followed 200 to 900 years later by a rebound in the number of

  2. Understanding population structure and historical demography in a conservation context: population genetics of the endangered Kirengeshoma palmata (Hydrangeaceae).

    PubMed

    Yuan, Na; Sun, Yi; Comes, Hans-Peter; Fu, Cheng-Xin; Qiu, Ying-Xiong

    2014-03-01

    Both historical and contemporary microevolutionary processes greatly influence the genetic patterns of East Asian plant endemics, but the spatial and temporal contexts of these processes remain poorly understood. Here, we investigate the relative influences of historical and contemporary gene flow and drift on the population genetic structure of Kirengeshoma palmata, a perennial herb from East China and South Japan. We used data from nine polymorphic microsatellite loci to assess the levels of genetic diversity, effective population size, and contemporary and historical gene flow for six of the seven known populations. We found high levels of inbreeding and allelic diversity within populations. Both contemporary and historical migration rates among populations were low, and a test of alternate models of population history strongly favored a model of long-term drift-migration equilibrium. We inferred declines in population size ca. 10,000-100,000 yr ago, but failed to detect recent declines. Bayesian clustering divided K. palmata populations into three genetic clusters, two of which were consistent with a glacial refugium hypothesis for two mountain ranges in East China. These results suggest that anthropogenic fragmentation has had little effect on the genetic characteristics of Chinese K. palmata. Rather, past decline in population size due to Late Pleistocene climate change as well as restricted pollen and seed dispersal may have contributed to low levels of both historical and contemporary gene flow, resulting in high genetic differentiation between adjacent mountain ranges due to genetic drift and inbreeding.

  3. Lion (Panthera leo) populations are declining rapidly across Africa, except in intensively managed areas.

    PubMed

    Bauer, Hans; Chapron, Guillaume; Nowell, Kristin; Henschel, Philipp; Funston, Paul; Hunter, Luke T B; Macdonald, David W; Packer, Craig

    2015-12-01

    We compiled all credible repeated lion surveys and present time series data for 47 lion (Panthera leo) populations. We used a Bayesian state space model to estimate growth rate-λ for each population and summed these into three regional sets to provide conservation-relevant estimates of trends since 1990. We found a striking geographical pattern: African lion populations are declining everywhere, except in four southern countries (Botswana, Namibia, South Africa, and Zimbabwe). Population models indicate a 67% chance that lions in West and Central Africa decline by one-half, while estimating a 37% chance that lions in East Africa also decline by one-half over two decades. We recommend separate regional assessments of the lion in the World Conservation Union (IUCN) Red List of Threatened Species: already recognized as critically endangered in West Africa, our analysis supports listing as regionally endangered in Central and East Africa and least concern in southern Africa. Almost all lion populations that historically exceeded ∼ 500 individuals are declining, but lion conservation is successful in southern Africa, in part because of the proliferation of reintroduced lions in small, fenced, intensively managed, and funded reserves. If management budgets for wild lands cannot keep pace with mounting levels of threat, the species may rely increasingly on these southern African areas and may no longer be a flagship species of the once vast natural ecosystems across the rest of the continent.

  4. Lion (Panthera leo) populations are declining rapidly across Africa, except in intensively managed areas

    PubMed Central

    Bauer, Hans; Chapron, Guillaume; Nowell, Kristin; Henschel, Philipp; Funston, Paul; Macdonald, David W.; Packer, Craig

    2015-01-01

    We compiled all credible repeated lion surveys and present time series data for 47 lion (Panthera leo) populations. We used a Bayesian state space model to estimate growth rate-λ for each population and summed these into three regional sets to provide conservation-relevant estimates of trends since 1990. We found a striking geographical pattern: African lion populations are declining everywhere, except in four southern countries (Botswana, Namibia, South Africa, and Zimbabwe). Population models indicate a 67% chance that lions in West and Central Africa decline by one-half, while estimating a 37% chance that lions in East Africa also decline by one-half over two decades. We recommend separate regional assessments of the lion in the World Conservation Union (IUCN) Red List of Threatened Species: already recognized as critically endangered in West Africa, our analysis supports listing as regionally endangered in Central and East Africa and least concern in southern Africa. Almost all lion populations that historically exceeded ∼500 individuals are declining, but lion conservation is successful in southern Africa, in part because of the proliferation of reintroduced lions in small, fenced, intensively managed, and funded reserves. If management budgets for wild lands cannot keep pace with mounting levels of threat, the species may rely increasingly on these southern African areas and may no longer be a flagship species of the once vast natural ecosystems across the rest of the continent. PMID:26504235

  5. Multiple stressor effects in relation to declining amphibian populations

    USGS Publications Warehouse

    Linder, Greg L.; Krest, Sherry K.; Sparling, Donald; Little, E.

    2003-01-01

    Original research discusses the protocols and approaches to studying the effects of multiple environmental stressors on amphibian populations and gives new perspectives on this complicated subject. This new publication integrates a variety of stressors that can act in concert and may ultimately cause a decline in amphibian populations.Sixteen peer-reviewed papers cover:Toxicity Assessment examines methods, which range from long-established laboratory approaches for evaluating adverse chemical effects to amphibians, to methods that link chemicals in surface waters, sediments, and soils with adverse effects observed among amphibians in the field.Field and Laboratory Studies illustrates studies in the evaluation of multiple stressor effects that may lead to declining amphibian populations. A range of laboratory and field studies of chemicals, such as herbicides, insecticides, chlorinated organic compounds, metals, and complex mixtures are also included.Causal Analysis demonstrates the range of tools currently available for evaluating "cause-effect" relationships between environmental stressors and declining amphibian populations.Audience: This new publication is a must-have for scientists and resource management professionals from diverse fields, including ecotoxicology, chemistry, ecology, field biology, conservation biology, and natural resource management.

  6. The Population Health Approach in Historical Perspective

    PubMed Central

    Szreter, Simon

    2003-01-01

    The origin of the population health approach is an historic debate over the relationship between economic growth and human health. In Britain and France, the Industrial Revolution disrupted population health and stimulated pioneering epidemiological studies, informing the early preventive public health movement. A century-long process of political adjustment between the forces of liberal democracy and propertied interests ensued. The 20th-century welfare states resulted as complex political mechanisms for converting economic growth into enhanced population health. However, the rise of a “neoliberal” agenda, denigrating the role of government, has once again brought to the fore the importance of prevention and a population health approach to map and publicize the health impacts of this new phase of “global” economic growth. PMID:12604486

  7. The population health approach in historical perspective.

    PubMed

    Szreter, Simon

    2003-03-01

    The origin of the population health approach is an historic debate over the relationship between economic growth and human health. In Britain and France, the Industrial Revolution disrupted population health and stimulated pioneering epidemiological studies, informing the early preventive public health movement. A century-long process of political adjustment between the forces of liberal democracy and propertied interests ensued. The 20th-century welfare states resulted as complex political mechanisms for converting economic growth into enhanced population health. However, the rise of a "neoliberal" agenda, denigrating the role of government, has once again brought to the fore the importance of prevention and a population health approach to map and publicize the health impacts of this new phase of "global" economic growth.

  8. Quantifying population declines based on presence-only records for red-list assessments.

    PubMed

    Cruickshank, Sam S; Ozgul, Arpat; Zumbach, Silvia; Schmidt, Benedikt R

    2016-10-01

    Accurate trend estimates are necessary for understanding which species are declining and which are most in need of conservation action. Imperfect species detection may result in unreliable trend estimates because this may lead to the overestimation of declines. Because many management decisions are based on population trend estimates, such biases could have severe consequences for conservation policy. We used an occupancy-modeling framework to estimate detectability and calculate nationwide population trends for 14 Swiss amphibian species both accounting for and ignoring imperfect detection. Through the application of International Union for Conservation of Nature Red List criteria to the different trend estimates, we assessed whether ignoring imperfect detection could affect conservation policy. Imperfect detection occurred for all species and detection varied substantially among species, which led to the overestimation of population declines when detectability was ignored. Consequently, accounting for imperfect detection lowered the red-list risk category for 5 of the 14 species assessed. We demonstrate that failing to consider species detectability can have serious consequences for species management and that occupancy modeling provides a flexible framework to account for observation bias and improve assessments of conservation status. A problem inherent to most historical records is that they contain presence-only data from which only relative declines can be estimated. A move toward the routine recording of nonobservation and absence data is essential if conservation practitioners are to move beyond this toward accurate population trend estimation.

  9. Population genetic analysis reveals a long-term decline of a threatened endemic Australian marsupial.

    PubMed

    Hansen, Birgita D; Harley, Daniel K P; Lindenmayer, David B; Taylor, Andrea C

    2009-08-01

    Since European colonization, Leadbeater's possum (Gymnobelideus leadbeateri) has declined across its range to the point where it is now only patchily distributed within the montane ash forests of the Central Highlands of Victoria. The loss of large hollow-bearing trees coupled with inadequate recruitment of mature ash forest has been predicted to result in a reduction in population size of up to 90% by 2020. Furthermore, bioclimatic analyses have suggested additional reductions in the species' distribution under a variety of climate change scenarios. Using a panel of 15 highly resolving microsatellite markers and mitochondrial control region sequence data, we infer past and present gene flow. Populations in the northern part of the core range were highly admixed, and showed no signs of either current or historical barriers to gene flow. A marginal, isolated and inbred population at Yellingbo was highly genetically differentiated, both in terms of current and historic genetic structure. Sequence data confirmed the conclusions from earlier genetic simulation studies that the Yellingbo population has been isolated from the rest of the species range since before European-induced changes to the montane landscape, and formed part of a larger genetic unit that is now otherwise extinct. Historic loss of maternal lineages in the Central Highlands of Victoria was detected despite signals of immigration, indicating population declines that most probably coincided with changes in climate at the end of the Pleistocene. Given ongoing habitat loss and the recent (February 2009) wildfire in the Central Highlands, we forecast (potentially extensive) demographic declines, in line with predicted range reductions under climate change scenarios.

  10. Population Declines of Mountain Coqui (Eleutherodactylus portoricensis) in the Cordillera Central of Puerto Rico

    PubMed Central

    Barker, Brittany S.; Ríos-Franceschi, Alejandro

    2014-01-01

    The Mountain Coqui (Eleutherodactylus portoricensis) is a frog endemic to montane rainforests in the Cordillera Central and Luquillo Mountains of Puerto Rico. Classified as endangered by the IUCN Red List and as vulnerable by the Department of Natural and Environmental Resources of Puerto Rico, this species has undergone considerable decline in the Luquillo Mountains. To evaluate the population status of E. portoricensis across its entire range, we conducted ~87 hours of surveys at 18 historical localities and 25 additional localities that we considered suitable for this species. We generated occupancy models to estimate the probability of occurrence at surveyed sites and to identify geographic and climatic factors affecting site occupancy. We also constructed a suitability map to visualize population status in relation to the presence of land cover at elevations where the species has been documented, and determined the dates when populations were last detected at historical localities. Eleutherodactylus portoricensis was detected at 14 of 43 localities, including 10 of 18 historical localities, but it was not detected at any localities west of Aibonito (western Cordillera Central). Occupancy models estimated the probability of occurrence for localities in the western Cordillera Central as zero. Site occupancy was positively associated with montane cloud forest, and negatively associated with the western Cordillera Central, maximum temperature, and precipitation seasonality. The suitability map suggests that declines have occurred despite the presence of suitable habitat. We suggest upgrading the extinction risk of E. portoricensis and potentially developing a captive breeding program for this species. PMID:25685250

  11. Declining scaup populations: issues, hypotheses, and research needs

    USGS Publications Warehouse

    Austin, J.E.; Afton, A.D.; Anderson, M.G.; Clark, R.G.; Custer, Christine M.; Lawrence, J.S.; Pollard, J.B.; Ringelman, J.K.

    2000-01-01

    The population estimate for greater (Aythya marila) and lesser (Aythya affinis) scaup (combined) has declined dramatically since the early 1980s to record lows in 1998. The 1998 estimate of 3.47 million scaup is far below the goal of 6.3 million set in the North American Waterfowl Management Plan (NAWMP), causing concern among biologists and hunters. We summarize issuesof concern, hypotheses for factors contributing to the population decline, and research and management needs recommended by participants of the Scaup Workshop, held in September 1999. We believe that contaminants, lower female survival, and reduced recruitment due to changes in food resources or breedingground habitats are primary factors contributing to the decline. These factors are not mutually exclusive but likely interact across seasons. Workshop participants identified seven action items. We need to further delineate where declines in breeding populations have occurred, with a primary focus on the western Canadian boreal forest, where declines appear to be most pronounced. Productivity in various areas and habitats throughout the breeding range needs to be assessed by conducting retrospective analyses of existing data and by intensive field studies at broad and local scales. Annual and seasonal survival rates need to be determined in order to assess the role of harvest or natural mortality. Effects of contaminants on reproduction, female body condition, and behavior must be investigated. Use, distribution, and role of food resources relative to body condition and reproduction need to be examined to better understand seasonal dynamics of nutrient reserves and the role in reproductive success. Affiliations among breeding, migration, and wintering areas must be assessed in order to understand differential exposure to harvest or contaminants, and differential reproductive success and recruitment. Biologists and agencies need to gather and improve information needed to manage greater and lesser

  12. Influence of Nonhost Plants on Population Decline of Rotylenchulus reniformis

    PubMed Central

    Caswell, E. P.; DeFrank, J.; Apt, W. J.; Tang, C. S.

    1991-01-01

    The influence of Chloris gayana, Crotalaria juncea, Digitaria decumbens, Tagetes patula, and a chitin-based soil amendment on Hawaiian populations of Rotylenchulus reniformis was examined. Chloris gayana was a nonhost for R. reniformis. The nematode did not penetrate the roots, and in greenhouse and field experiments, C. gayana reduced reniform nematode numbers at least as well as fallow. Tagetes patula was a poor host for reniform nematode and reduced reniform nematode numbers in soil better than did fallow. Crotalaria juncea was a poor host for R. reniformis, and only a small fraction of the nematode population penetrated the roots. Crotalaria juncea and D. decumbens reduced reniform nematode populations at least as well as fallow. A chitin-based soil amendment, applied at 2.24 t/ha to fallow soil, did not affect the population decline of reniform nematode. PMID:19283098

  13. Climate change and pollution speed declines in zebrafish populations.

    PubMed

    Brown, A Ross; Owen, Stewart F; Peters, James; Zhang, Yong; Soffker, Marta; Paull, Gregory C; Hosken, David J; Wahab, M Abdul; Tyler, Charles R

    2015-03-17

    Endocrine disrupting chemicals (EDCs) are potent environmental contaminants, and their effects on wildlife populations could be exacerbated by climate change, especially in species with environmental sex determination. Endangered species may be particularly at risk because inbreeding depression and stochastic fluctuations in male and female numbers are often observed in the small populations that typify these taxa. Here, we assessed the interactive effects of water temperature and EDC exposure on sexual development and population viability of inbred and outbred zebrafish (Danio rerio). Water temperatures adopted were 28 °C (current ambient mean spawning temperature) and 33 °C (projected for the year 2100). The EDC selected was clotrimazole (at 2 μg/L and 10 μg/L), a widely used antifungal chemical that inhibits a key steroidogenic enzyme [cytochrome P450(CYP19) aromatase] required for estrogen synthesis in vertebrates. Elevated water temperature and clotrimazole exposure independently induced male-skewed sex ratios, and the effects of clotrimazole were greater at the higher temperature. Male sex ratio skews also occurred for the lower clotrimazole exposure concentration at the higher water temperature in inbred fish but not in outbred fish. Population viability analysis showed that population growth rates declined sharply in response to male skews and declines for inbred populations occurred at lower male skews than for outbred populations. These results indicate that elevated temperature associated with climate change can amplify the effects of EDCs and these effects are likely to be most acute in small, inbred populations exhibiting environmental sex determination and/or differentiation.

  14. Climate change and pollution speed declines in zebrafish populations

    PubMed Central

    Owen, Stewart F.; Peters, James; Zhang, Yong; Soffker, Marta; Paull, Gregory C.; Hosken, David J.; Wahab, M. Abdul; Tyler, Charles R.

    2015-01-01

    Endocrine disrupting chemicals (EDCs) are potent environmental contaminants, and their effects on wildlife populations could be exacerbated by climate change, especially in species with environmental sex determination. Endangered species may be particularly at risk because inbreeding depression and stochastic fluctuations in male and female numbers are often observed in the small populations that typify these taxa. Here, we assessed the interactive effects of water temperature and EDC exposure on sexual development and population viability of inbred and outbred zebrafish (Danio rerio). Water temperatures adopted were 28 °C (current ambient mean spawning temperature) and 33 °C (projected for the year 2100). The EDC selected was clotrimazole (at 2 μg/L and 10 μg/L), a widely used antifungal chemical that inhibits a key steroidogenic enzyme [cytochrome P450(CYP19) aromatase] required for estrogen synthesis in vertebrates. Elevated water temperature and clotrimazole exposure independently induced male-skewed sex ratios, and the effects of clotrimazole were greater at the higher temperature. Male sex ratio skews also occurred for the lower clotrimazole exposure concentration at the higher water temperature in inbred fish but not in outbred fish. Population viability analysis showed that population growth rates declined sharply in response to male skews and declines for inbred populations occurred at lower male skews than for outbred populations. These results indicate that elevated temperature associated with climate change can amplify the effects of EDCs and these effects are likely to be most acute in small, inbred populations exhibiting environmental sex determination and/or differentiation. PMID:25733876

  15. Towards renewed fears of population and family decline?

    PubMed

    Gauthier, A H

    1993-01-01

    The emphasis of the analysis of population and family policy in industrialized countries (Western Europe, North America, Australia, and New Zealand) is on ascertaining the extent to which governments have been responsive to recent demographic changes, the point of view expressed, and the differences in response between the present and in the 1930s. Family and population are treated as separate entities regardless of their policy links; the general attitudes inherent in commission reports is the focus rather than government interventions such as family benefits or concrete policy measures. Regional and local government initiatives are considered only in the case of Quebec. Nongovernmental organizations have played a larger role in the present. Over the past 30 years, governments in most counties have responded to demographic changes, but the way issues were treated was divergent. During the 1930s, population decline was seen in the context of a military argument and concern have been population aging. There has been greater acceptance of nontraditional family forms. County differences showed France as the only country with an explicit pronatalist position and intervention by governmental and nongovernmental groups. Germany has been unable to directly attend to pronatalism, because of the Nazi population policy experiments; attention has been directed to public child care, albeit underdeveloped, and other obstacles to female employment. In contrast, Nordic countries have been very supportive of working mothers and fathers, and sex equality. There have been extensive maternity and parental leave support systems in place for some time, and extensive child care networks. In Britain and the US, fears of overpopulation have dominated the agenda, along with nonstate interference with family life and acceptance of market forces as a dominant influence. The focus was on poverty, single parents, and welfare dependency. Southern European countries have shown great concern

  16. Declining scaup populations: A retrospective analysis of long-term population and harvest survey data

    USGS Publications Warehouse

    Afton, A.D.; Anderson, M.G.

    2001-01-01

    We examined long-term databases concerning population status of scaup (lesser [Aythya affinis] and greater scaup [A. marila] combined) and harvest statistics of lesser scaup to identify factors potentially limiting population growth. Specifically, we explored evidence for and against the general hypotheses that scaup populations have declined in association with declining recruitment and/or female survival. We examined geographic heterogeneity in scaup demographic patterns that could yield evidence about potential limiting factors. Several biases exist in survey methodology used to estimate scaup populations and harvest statistics; however, none of these biases likely accounted for our major findings that (1) the continental scaup breeding population has declined over the last 20 years, with widespread and consistent declines within surveyed areas of the Canadian western boreal forest where most lesser scaup breed; (2) sex ratios of lesser scaup in the U.S. harvest have increased (more males now relative to females); and (3) age ratios of lesser scaup in the U.S. harvest have declined (fewer immatures now relative to adults), especially in the midcontinent region. We interpreted these major findings as evidence that (1) recruitment of lesser scaup has declined over the last 20 years, particularly in the Canadian western boreal forest; and (2) survival of female lesser scaup has declined relative to that of males. We found little evidence that harvest was associated with the scaup population decline. Our findings underscore the need for both improvements and changes to population survey procedures and new research to discriminate among various hypotheses explaining the recent scaup population decline.

  17. Early detection of population declines: high power of genetic monitoring using effective population size estimators

    PubMed Central

    Antao, Tiago; Pérez-Figueroa, Andrés; Luikart, Gordon

    2011-01-01

    Early detection of population declines is essential to prevent extinctions and to ensure sustainable harvest. We evaluated the performance of two Ne estimators to detect population declines: the two-sample temporal method and a one-sample method based on linkage disequilibrium (LD). We used simulated data representing a wide range of population sizes, sample sizes and number of loci. Both methods usually detect a population decline only one generation after it occurs if Ne drops to less than approximately 100, and 40 microsatellite loci and 50 individuals are sampled. However, the LD method often out performed the temporal method by allowing earlier detection of less severe population declines (Ne approximately 200). Power for early detection increased more rapidly with the number of individuals sampled than with the number of loci genotyped, primarily for the LD method. The number of samples available is therefore an important criterion when choosing between the LD and temporal methods. We provide guidelines regarding design of studies targeted at monitoring for population declines. We also report that 40 single nucleotide polymorphism (SNP) markers give slightly lower precision than 10 microsatellite markers. Our results suggest that conservation management and monitoring strategies can reliably use genetic based methods for early detection of population declines. PMID:25567959

  18. Historical and Contemporary DNA Indicate Fisher Decline and Isolation Occurred Prior to the European Settlement of California

    PubMed Central

    Tucker, Jody M.; Schwartz, Michael K.; Truex, Richard L.; Pilgrim, Kristine L.; Allendorf, Fred W.

    2012-01-01

    Establishing if species contractions were the result of natural phenomena or human induced landscape changes is essential for managing natural populations. Fishers (Martes pennanti) in California occur in two geographically and genetically isolated populations in the northwestern mountains and southern Sierra Nevada. Their isolation is hypothesized to have resulted from a decline in abundance and distribution associated with European settlement in the 1800s. However, there is little evidence to establish that fisher occupied the area between the two extant populations at that time. We analyzed 10 microsatellite loci from 275 contemporary and 21 historical fisher samples (1880–1920) to evaluate the demographic history of fisher in California. We did not find any evidence of a recent (post-European) bottleneck in the northwestern population. In the southern Sierra Nevada, genetic subdivision within the population strongly influenced bottleneck tests. After accounting for genetic subdivision, we found a bottleneck signal only in the northern and central portions of the southern Sierra Nevada, indicating that the southernmost tip of these mountains may have acted as a refugium for fisher during the anthropogenic changes of the late 19th and early 20th centuries. Using a coalescent-based Bayesian analysis, we detected a 90% decline in effective population size and dated the time of decline to over a thousand years ago. We hypothesize that fisher distribution in California contracted to the two current population areas pre-European settlement, and that portions of the southern Sierra Nevada subsequently experienced another more recent bottleneck post-European settlement. PMID:23300783

  19. Historical citizen science to understand and predict climate-driven trout decline.

    PubMed

    Clavero, Miguel; Ninyerola, Miquel; Hermoso, Virgilio; Filipe, Ana Filipa; Pla, Magda; Villero, Daniel; Brotons, Lluís; Delibes, Miguel

    2017-01-11

    Historical species records offer an excellent opportunity to test the predictive ability of range forecasts under climate change, but researchers often consider that historical records are scarce and unreliable, besides the datasets collected by renowned naturalists. Here, we demonstrate the relevance of biodiversity records developed through citizen-science initiatives generated outside the natural sciences academia. We used a Spanish geographical dictionary from the mid-nineteenth century to compile over 10 000 freshwater fish records, including almost 4 000 brown trout (Salmo trutta) citations, and constructed a historical presence-absence dataset covering over 2 000 10 × 10 km cells, which is comparable to present-day data. There has been a clear reduction in trout range in the past 150 years, coinciding with a generalized warming. We show that current trout distribution can be accurately predicted based on historical records and past and present values of three air temperature variables. The models indicate a consistent decline of average suitability of around 25% between 1850s and 2000s, which is expected to surpass 40% by the 2050s. We stress the largely unexplored potential of historical species records from non-academic sources to open new pathways for long-term global change science.

  20. [The decline in population growth, income distribution, and economic recession].

    PubMed

    Banguero, H

    1983-05-01

    This work uses Keynesian principles and an analysis of the Colombian population in the 1970s to argue that the Colombian policy of slowing population growth, which was adopted with the aim of improving the general welfare of the population, has had shortterm negative effects on effective demand and thus on the level of employment and welfare. These negative effects were caused by the inflexibility of income distribution, which prevented expansion of the internal market, complicated by the stagnant condition of the external sector and the budget deficit. The results of the Colombian case study demonstrate how the deceleration of population growth beginning in the 1960s had a significant impact on the levels of consumption and savings and on the patterns of consumption, leading to low levels of investment and little dynamism. Although the current Colombian economic recession is aggravated by contextual factors such as the world economic recession, the high cost of capital, the industrial recession, and declining food production among others, at the core of the crisis are longer term structural determinants such as the decline in the rate of population growth and the highly unequal distribution of income and wealth, which have contributed to a shrinking of the internal market for some types of goods. Given the unlikelihood of renewed rapid population growth, the Keynesian model suggests that the only alternative for increasing aggregate demand is state intervention through public spending and investment and reorientation of the financial system to achieve a dynamic redistribution of income. Based on these findings and on proposals of other analysts, a stragegy for revitalization is proposed which would imply a gradual income redistribution to allow increased consumption of mass produced goods by the low income groups. Direct consumption subsidies would be avoided because of their inflationary and import-expanding tendencies; rather, incentives and support would be

  1. Addressing wild turkey population declines using structured decision making

    USGS Publications Warehouse

    Robinson, Kelly F.; Fuller, Angela K.; Schiavone, Michael V.; Swift, Bryan; Diefenbach, Duane R.; Siemer, William F.; Decker, Daniel J.

    2017-01-01

    We present a case study from New York, USA, of the use of structured decision making (SDM) to identify fall turkey harvest regulations that best meet stakeholder objectives, in light of recent apparent declines in abundance of wild turkeys in the northeastern United States. We used the SDM framework to incorporate the multiple objectives associated with turkey hunting, stakeholder desires, and region-specific ecological and environmental factors that could influence fall harvest. We identified a set of 4 fall harvest regulations, composed of different season lengths and bag limits, and evaluated their relative achievement of the objectives. We used a stochastic turkey population model, statistical modeling, and expert elicitation to evaluate the consequences of each harvest regulation on each of the objectives. We conducted a statewide mail survey of fall turkey hunters in New York to gather the necessary information to evaluate tradeoffs among multiple objectives associated with hunter satisfaction. The optimal fall harvest regulation was a 2-week season and allowed for the harvest of 1 bird/hunter. This regulation was the most conservative of those evaluated, reflecting the concerns about recent declines in turkey abundance among agency wildlife biologists and the hunting public. Depending on the region of the state, the 2-week, 1-bird regulation was predicted to result in 7–32% more turkeys on the landscape after 5 years. The SDM process provided a transparent framework for setting fall turkey harvest regulations and reduced potential stakeholder conflict by explicitly taking the multiple objectives of different stakeholder groups into account.

  2. Arctic greening from warming promotes declines in caribou populations

    PubMed Central

    Fauchald, Per; Park, Taejin; Tømmervik, Hans; Myneni, Ranga; Hausner, Vera Helene

    2017-01-01

    The migratory tundra caribou herds in North America follow decadal population cycles, and browsing from abundant caribou could be expected to counteract the current climate-driven expansion of shrubs in the circumpolar tundra biome. We demonstrate that the sea ice cover in the Arctic Ocean has provided a strong signal for climate-induced changes on the adjacent caribou summer ranges, outperforming other climate indices in explaining the caribou-plant dynamics. We found no evidence of a negative effect of caribou abundance on vegetation biomass. On the contrary, we found a strong bottom-up effect in which a warmer climate related to diminishing sea ice has increased the plant biomass on the summer pastures, along with a paradoxical decline in caribou populations. This result suggests that this climate-induced greening has been accompanied by a deterioration of pasture quality. The shrub expansion in Arctic North America involves plant species with strong antibrowsing defenses. Our results might therefore be an early signal of a climate-driven shift in the caribou-plant interaction from a system with low plant biomass modulated by cyclic caribou populations to a system dominated by nonedible shrubs and diminishing herds of migratory caribou. PMID:28508037

  3. Tarangire revisited: Consequences of declining connectivity in a tropical ungulate population

    USGS Publications Warehouse

    Morrison, Thomas A.; Link, William; Newmark, William D.; Foley, Charles A.H.; Bolger, Douglas T.

    2016-01-01

    The hyper-abundance of migratory wildlife in many ecosystems depends on maintaining access to seasonally available resources. In Eastern and Southern Africa, land-use change and a loss of connectivity have coincided with widespread declines in the abundance and geographic range of ungulate populations. Using photographic capture-mark-recapture, we examine the historical pattern of loss of connectivity and its impact on population trends in a partially migratory wildebeest population in northern Tanzania. To estimate abundance, we use a novel modeling approach that overcomes bias associated with photo misidentifications. Our data indicate (1) diminished connectivity within and between seasonal areas as a result of human activities, (2) a reduction in the overall population size compared to historical numbers, with high variability over time, (3) the continued use of highly constrained movement corridors between the three main seasonal ranges, (4) higher recruitment in the non-migratory subpopulation (Lake Manyara National Park) than in other areas of the ecosystem, and (5) an increase in the relative abundance of resident to migrant wildebeest. Recent conservation efforts to protect seasonal habitat and to enforce anti-poaching policies outside protected areas have likely helped stabilize the population, at least temporarily, but we caution that several key vulnerabilities remain.

  4. Two centuries of the Scandinavian wolf population: patterns of genetic variability and migration during an era of dramatic decline.

    PubMed

    Flagstad, Ø; Walker, C W; Vilà, C; Sundqvist, A-K; Fernholm, B; Hufthammer, A K; Wiig, Ø; Koyola, I; Ellegren, H

    2003-04-01

    The grey wolf (Canis lupus) was numerous on the Scandinavian peninsula in the early 19th century. However, as a result of intense persecution, the population declined dramatically and was virtually extinct from the peninsula by the 1960s. We examined historical patterns of genetic variability throughout the period of decline, from 1829 to 1979. Contemporary Finnish wolves, considered to be representative of a large eastern wolf population, were used for comparison. Mitochondrial DNA (mtDNA) variability among historical Scandinavian wolves was significantly lower than in Finland while Y chromosome variability was comparable between the two populations. This may suggest that long-distance migration from the east has been male-biased. Importantly though, as the historical population was significantly differentiated from contemporary Finnish wolves, the overall immigration rate to the Scandinavian peninsula appears to have been low. Levels of variability at autosomal microsatellite loci were high by the early 1800s but declined considerably towards the mid-20th century. At this time, approximately 40% of the allelic diversity and 30% of the heterozygosity had been lost. After 1940, however, there is evidence of several immigration events, coinciding with episodes of marked population increase in Russian Karelia and subsequent westwards migration.

  5. UV-B Radiation Contributes to Amphibian Population Declines

    NASA Astrophysics Data System (ADS)

    Blaustein, Andrew

    2007-05-01

    UV-B (280-315 nm) radiation is the most significant biologically damaging radiation at the terrestrial surface. At the organismal level, UV-B radiation can slow growth rates, cause immune dysfunction and result in sublethal damage. UV-B radiation can lead to mutations and cell death. Over evolutionary time, UV radiation has been an important stressor on living organisms. Natural events, including impacts from comets and asteroids, volcanic activity, supernova explosions and solar flares, can cause large-scale ozone depletion with accompanying increases in UV radiation. However, these natural events are transient. Moreover, the amount of ozone damage due to natural events depends upon a number of variables, including the magnitude of the event. This is different from modern-day human-induced production of chlorofluorocarbons (CFCs) and other chemicals that deplete stratospheric ozone continuously, resulting in long-term increases in UV-B radiation at the surface of the earth. We will briefly review the effects of UV-B exposure in one group of aquatic organisms_amphibians. UV-B has been implicated as a possible factor contributing to global declines and range reductions in amphibian populations.

  6. FACTORS IMPLICATED IN AMPHIBIAN POPULATION DECLINES IN THE UNITED STATES

    EPA Science Inventory

    This study identified the factors responsible for the decline of native amphibians in the U.S. The type of land use, the introduction of exotic animal species, and chemical contamination were identified as the most likely causes of decline.

  7. POPULATION DECLINES OF THE PUERTO RICAN VIREO IN GUANICA FOREST.

    Treesearch

    JOHN FAABORG; KATE M. DUGGER; WAYNE J. ARENDT; BETHANY L. WOODWORTH; MICHAEL E. BALTZ

    1997-01-01

    Abundance of the Puerto Rican Vireo (Vireo Zutimeri) in Guanica Forest, Puerto Rico, has declined gradually over the period 1973-1996 as determined by constant effort mist netting. Concurrent studies of breeding vireos show low nesting success, primarily due to parasitism by Shiny Cowbirds (Molothrus bonariensis). This decline may reflect the rather recent entry of the...

  8. Socio-economic status and fertility decline: Insights from historical transitions in Europe and North America.

    PubMed

    Dribe, Martin; Breschi, Marco; Gagnon, Alain; Gauvreau, Danielle; Hanson, Heidi A; Maloney, Thomas N; Mazzoni, Stanislao; Molitoris, Joseph; Pozzi, Lucia; Smith, Ken R; Vézina, Hélène

    2017-03-01

    The timings of historical fertility transitions in different regions are well understood by demographers, but much less is known regarding their specific features and causes. In the study reported in this paper, we used longitudinal micro-level data for five local populations in Europe and North America to analyse the relationship between socio-economic status and fertility during the fertility transition. Using comparable analytical models and class schemes for each population, we examined the changing socio-economic differences in marital fertility and related these to common theories on fertility behaviour. Our results do not provide support for the hypothesis of universally high fertility among the upper classes in pre-transitional society, but do support the idea that the upper classes acted as forerunners by reducing their fertility before other groups. Farmers and unskilled workers were the latest to start limiting their fertility. Apart from these similarities, patterns of class differences in fertility varied significantly between populations.

  9. Linking Lesser Scaup Population Decline To The Environment:Issues Of Time, Space And Scale

    NASA Astrophysics Data System (ADS)

    Kahara, S. N.

    2005-05-01

    Continental breeding populations of Lesser scaup(Aythya affinis)have been declining since the 1980's. The most comprehensive explanation for this is the Spring Condition Hypothesis (SCH),which predicts that female lesser scaup are arriving on breeding/nesting areas in poorer condition than they did historically, possibly due to lack of sufficient forage along spring migration routes. Diet analyses of lesser scaup have shown aquatic macroinvertebrates to be their primary food, inferring that prey availability is a key factor influencing body condition and reproductive success, however, factors affecting macro invertebrate abundance in the prairie pothole region (PPR)and their relationship to lesser scaup are not well known. Although lesser scaup surveys span several years, lack of long-term macroinvertebrate data raises critical questions about linking their population decline to changes in macroinvertebrate abundance. The aim of this study is to test the viability of the SCH by collating literature from previous and current research, combining field data, microcosms and remote sensing to investigate both the causes as well as the mechanisms behind of the problem and to use this as the basis for predicting long term trends and possible remediation.

  10. Using latent selection difference to model persistence in a declining population.

    PubMed

    Erickson, Mara E; Found-Jackson, Christine; Boyce, Mark S

    2014-01-01

    Population persistence is a direct measure of the viability of a population. Monitoring the distribution of declining populations or subpopulations over time can yield estimates of persistence, which we show can be modeled as a latent selection difference (LSD) contrasting attributes of sites where populations have persisted versus those that have not. Predicted persistence can be modeled with predictor covariates to identify factors correlated with species persistence. We demonstrate how to model persistence based on changes in occupancy that can include adjustments for detection probability. Using a known historical distribution of the western grebe (Aechmophorus occidentalis), we adapted methods originally developed for occupancy modeling to evaluate how environmental covariates including emergent vegetation and human developments have affected western grebe persistence in Alberta. The relative probability of persistence was correlated with the extent of shoreline bulrush (Scirpus lacustris), which is important vegetation for nesting cover. We also documented that western grebe populations were less likely to persist on lakes in the boreal forest, primarily located on the northern boundary of the species' range. Factors influencing occupancy were different than those determining persistence by western grebes; persistence and occupancy were not correlated. Persistence was more likely on lakes with recreational development, reflecting reliance by grebes on the larger, fish-bearing waterbodies that also are attractive for lakeshore development. Unfortunately, the correlation with recreational development on Alberta's lakes puts grebes at risk for loss of brood-rearing habitats--primary threats to altricial birds--if steps are not taken to prevent disturbance to bulrush stands. Identifying factors related to the persistence of a species--especially one in decline--is a fundamental step in conservation management.

  11. North American osprey populations and contaminants: Historic and contemporary perspectives

    USGS Publications Warehouse

    Henny, Charles J.; Grove, Robert A.; Kaiser, James L.; Johnson, Branden L.

    2010-01-01

    Osprey (Pandion haliaetus) populations were adversely affected by DDT and perhaps other contaminants in the United States and elsewhere. Reduced productivity, eggshell thinning, and high DDE concentrations in eggs were the signs associated with declining osprey populations in the 1950s, 1960s, and 1970s. The species was one of the first studied on a large scale to bring contaminant issues into focus. Although few quantitative population data were available prior to the 1960s, many osprey populations in North America were studied during the 1960s and 1970s with much learned about basic life history and biology. This article reviews the historical and current effects of contaminants on regional osprey populations. Breeding populations in many regions of North America showed post-DDT-era (1972) population increases of varying magnitudes, with many populations now appearing to stabilize at much higher numbers than initially reported in the 1970s and 1980s. However, the magnitude of regional population increases in the United States between 1981 (first Nationwide Survey, ≈8,000 pairs), when some recovery had already occurred, 1994 (second survey, ≈14,200), and 2001 (third survey, ≈16,000–19,000), or any other years, is likely not a simple response to the release from earlier contaminant effects, but a response to multi-factorial effects. This indirect "contaminant effects" measurement comparing changes (i.e., recovery) in post-DDT-era population numbers over time is probably confounded by changing human attitudes toward birds of prey (shooting, destroying nests, etc.), changing habitats, changing fish populations, and perhaps competition from other species. The species' adaptation to newly created reservoirs and its increasing use of artificial nesting structures (power poles, nesting platforms, cell towers, channel markers, offshore duck blinds, etc.) are two important factors. The timing of the initial use of artificial nesting structures, which replaced

  12. North American osprey populations and contaminants: historic and contemporary perspectives.

    PubMed

    Henny, Charles J; Grove, Robert A; Kaiser, James L; Johnson, Branden L

    2010-10-01

    Osprey (Pandion haliaetus) populations were adversely affected by DDT and perhaps other contaminants in the United States and elsewhere. Reduced productivity, eggshell thinning, and high DDE concentrations in eggs were the signs associated with declining osprey populations in the 1950s, 1960s, and 1970s. The species was one of the first studied on a large scale to bring contaminant issues into focus. Although few quantitative population data were available prior to the 1960s, many osprey populations in North America were studied during the 1960s and 1970s with much learned about basic life history and biology. This article reviews the historical and current effects of contaminants on regional osprey populations. Breeding populations in many regions of North America showed post-DDT-era (1972) population increases of varying magnitudes, with many populations now appearing to stabilize at much higher numbers than initially reported in the 1970s and 1980s. However, the magnitude of regional population increases in the United States between 1981 (first Nationwide Survey, ∼8,000 pairs), when some recovery had already occurred, 1994 (second survey, ∼14,200), and 2001 (third survey, ∼16,000-19,000), or any other years, is likely not a simple response to the release from earlier contaminant effects, but a response to multi-factorial effects. This indirect "contaminant effects" measurement comparing changes (i.e., recovery) in post-DDT-era population numbers over time is probably confounded by changing human attitudes toward birds of prey (shooting, destroying nests, etc.), changing habitats, changing fish populations, and perhaps competition from other species. The species' adaptation to newly created reservoirs and its increasing use of artificial nesting structures (power poles, nesting platforms, cell towers, channel markers, offshore duck blinds, etc.) are two important factors. The timing of the initial use of artificial nesting structures, which replaced

  13. North American osprey populations and contaminants: Historic and contemporary perspectives

    USGS Publications Warehouse

    Henny, Charles J.; Grove, Robert A.; Kaiser, James L.; Johnson, Branden L.

    2010-01-01

    Osprey (Pandion haliaetus) populations were adversely affected by DDT and perhaps other contaminants in the United States and elsewhere. Reduced productivity, eggshell thinning, and high DDE concentrations in eggs were the signs associated with declining osprey populations in the 1950s, 1960s, and 1970s. The species was one of the first studied on a large scale to bring contaminant issues into focus. Although few quantitative population data were available prior to the 1960s, many osprey populations in North America were studied during the 1960s and 1970s with much learned about basic life history and biology. This article reviews the historical and current effects of contaminants on regional osprey populations. Breeding populations in many regions of North America showed post-DDT-era (1972) population increases of varying magnitudes, with many populations now appearing to stabilize at much higher numbers than initially reported in the 1970s and 1980s. However, the magnitude of regional population increases in the United States between 1981 (first Nationwide Survey, ∼8,000 pairs), when some recovery had already occurred, 1994 (second survey, ∼14,200), and 2001 (third survey, ∼16,000–19,000), or any other years, is likely not a simple response to the release from earlier contaminant effects, but a response to multi-factorial effects. This indirect “contaminant effects” measurement comparing changes (i.e., recovery) in post-DDT-era population numbers over time is probably confounded by changing human attitudes toward birds of prey (shooting, destroying nests, etc.), changing habitats, changing fish populations, and perhaps competition from other species. The species' adaptation to newly created reservoirs and its increasing use of artificial nesting structures (power poles, nesting platforms, cell towers, channel markers, offshore duck blinds, etc.) are two important factors. The timing of the initial use of artificial nesting structures, which replaced

  14. Evidence of genetic distinction and long-term population decline in wolves (Canis lupus) in the Italian Apennines.

    PubMed

    Lucchini, V; Galov, A; Randi, E

    2004-03-01

    Historical information suggests the occurrence of an extensive human-caused contraction in the distribution range of wolves (Canis lupus) during the last few centuries in Europe. Wolves disappeared from the Alps in the 1920s, and thereafter continued to decline in peninsular Italy until the 1970s, when approximately 100 individuals survived, isolated in the central Apennines. In this study we performed a coalescent analysis of multilocus DNA markers to infer patterns and timing of historical population changes in wolves surviving in the Apennines. This population showed a unique mitochondrial DNA control-region haplotype, the absence of private alleles and lower heterozygosity at microsatellite loci, as compared to other wolf populations. Multivariate, clustering and Bayesian assignment procedures consistently assigned all the wolf genotypes sampled in Italy to a single group, supporting their genetic distinction. Bottleneck tests showed evidences of population decline in the Italian wolves, but not in other populations. Results of a Bayesian coalescent model indicate that wolves in Italy underwent a 100- to 1000-fold population contraction over the past 2000-10,000 years. The population decline was stronger and longer in peninsular Italy than elsewhere in Europe, suggesting that wolves have apparently been genetically isolated for thousands of generations south of the Alps. Ice caps covering the Alps at the Last Glacial Maximum (c. 18,000 years before present), and the wide expansion of the Po River, which cut the alluvial plains throughout the Holocene, might have provided effective geographical barriers to wolf dispersal. More recently, the admixture of Alpine and Apennine wolf populations could have been prevented by deforestation, which was already widespread in the fifteenth century in northern Italy. This study suggests that, despite the high potential rates of dispersal and gene flow, local wolf populations may not have mixed for long periods of time.

  15. AIRBORNE PESTICIDES AND POPULATION DECLINES OF A CALIFORNIA ALPINE FROG

    EPA Science Inventory

    The mountain yellow-legged frog (Rana muscosa) has disappeared from most of its historic localities in the Sierra Nevada of California, and airborne pesticides from the Central Valley have been implicated as a causal agent. To determine the distribution and temporal variation of ...

  16. AIRBORNE PESTICIDES AND POPULATION DECLINES OF A CALIFORNIA ALPINE FROG

    EPA Science Inventory

    The mountain yellow-legged frog (Rana muscosa) has disappeared from most of its historic localities in the Sierra Nevada of California, and airborne pesticides from the Central Valley have been implicated as a causal agent. To determine the distribution and temporal variation of ...

  17. The role of multiple stressor causes in declining amphibian populations: a wingspread workshop summary

    USGS Publications Warehouse

    Krest, S.K.; Linder, G.; Sparling, D.W.; Linder, Gregory L.; Krest, Sherry K.; Sparling, Donald W.; Little, Edward E.

    2003-01-01

    Numerous studies have documented the decline of amphibian populations over the past decade and no single factor has been the linked to these widespread declines. Determining the causes of declining amphibian populations worldwide has proven difficult because of the variety of anthropogenic and natural suspect agents. A Wingspread workshop, convened by The Society of Environmental Toxicology and Chemistry (SETAC), brought together individuals with expertise in the areas of amphibian biology, ecotoxicology, natural resource management, and environmental policy. This workshop had three objectives: 1) create a network for future discussions on multiple stressor causes of declines; 2) characterize and prioritize technical issues critical to the analysis of the decline problem; and 3) identify and develop resource management approaches to promote sustainable and healthy amphibian populations. The workshop proceedings will be summarized in a book entitled, 'Multiple Stressors and Declining Amphibian Populations: Evaluating Cause and Effect.' This paper summarizes the results of the workshop.

  18. The role of multiple stressor causes in declining amphibian populations: A wingspread workshop summary

    USGS Publications Warehouse

    Krest, S.K.; Linder, G.; Sparling, D.W.; ,

    2003-01-01

    Numerous studies have documented the decline of amphibian populations over the past decade and no single factor has been the linked to these widespread declines. Determining the causes of declining amphibian populations worldwide has proven difficult because of the variety of anthropogenic and natural suspect agents. A Wingspread workshop, convened by The Society of Environmental Toxicology and Chemistry (SETAC), brought together individuals with expertise in the areas of amphibian biology, ecotoxicology, natural resource management, and environmental policy. This workshop had three objectives: 1) create a network for future discussions on multiple Stressor causes of declines; 2) characterize and prioritize technical issues critical to the analysis of the decline problem; and 3) identify and develop resource management approaches to promote sustainable and healthy amphibian populations. The workshop proceedings will be summarized in a book entitled, "Multiple Stressors and Declining Amphibian Populations: Evaluating Cause and Effect." This paper summarizes the results of the workshop.

  19. Population decline induced by gonorrhoea and tuberculosis transmission: Micronesia during the Japanese occupation, 1919-45.

    PubMed

    Cassels, Susan; Singer, Burton H

    2010-12-01

    The islands of Yap in Micronesia survived a period of severe depopulation during the Japanese occupation from 1919 to 1945. Using data from historical documents, supplemented by ethnographic evidence, we calibrate a simulation model that accounts for this phenomenon. Our model tracks the reproduction histories of a synthetic cohort of women in Yap, including effects of infertility due to gonorrhoea as well as tuberculosis mortality, and predicts the net reproduction rate (NRR). In this particular case and throughout history, human migrations and associated social and cultural interactions have frequently been accompanied by dramatic changes in patterns of disease transmission and substantial demographic consequences. Despite the broad emphasis on mortality as a measure of demographic consequences in the historical and contemporary literature, there are important instances where life expectancy at birth, fertility rates, and total population size are important demographic consequences. We find that gonorrhoea may have significantly contributed to depopulation during the Japanese occupation of Micronesia, due to repeated infections and high risk of sterility. Results of our model suggest that gonorrhoea alone could have reduced the net reproduction rate by 82%, whereas deaths from tuberculosis may have contributed to a 17% decline.

  20. The effects of declining population growth on the demand for housing.

    Treesearch

    Thomas C. Marcin

    1974-01-01

    Declining population growth and unprecedented changes in the age structure of the population in the next several decades will profoundly affect housing demand in the next 50 years. A decline in housing demand and substantial change in the type of housing in demand are likely to occur by 1990.

  1. The complexity of amphibian population declines: understanding the role of cofactors in driving amphibian losses.

    PubMed

    Blaustein, Andrew R; Han, Barbara A; Relyea, Rick A; Johnson, Pieter T J; Buck, Julia C; Gervasi, Stephanie S; Kats, Lee B

    2011-03-01

    Population losses and extinctions of species are occurring at unprecedented rates, as exemplified by declines and extinctions of amphibians worldwide. However, studies of amphibian population declines generally do not address the complexity of the phenomenon or its implications for ecological communities, focusing instead on single factors affecting particular amphibian species. We argue that the causes for amphibian population declines are complex; may differ among species, populations, and life stages within a population; and are context dependent with multiple stressors interacting to drive declines. Because amphibians are key components of communities, we emphasize the importance of investigating amphibian declines at the community level. Selection pressures over evolutionary time have molded amphibian life history characteristics, such that they may remain static even in the face of strong, recent human-induced selection pressures.

  2. Is the current decline in malaria burden in sub-Saharan Africa due to a decrease in vector population?

    PubMed Central

    2011-01-01

    Background In sub-Saharan Africa (SSA), malaria caused by Plasmodium falciparum has historically been a major contributor to morbidity and mortality. Recent reports indicate a pronounced decline in infection and disease rates which are commonly ascribed to large-scale bed net programmes and improved case management. However, the decline has also occurred in areas with limited or no intervention. The present study assessed temporal changes in Anopheline populations in two highly malaria-endemic communities of NE Tanzania during the period 1998-2009. Methods Between 1998 and 2001 (1st period) and between 2003 and 2009 (2nd period), mosquitoes were collected weekly in 50 households using CDC light traps. Data on rainfall were obtained from the nearby climate station and were used to analyze the association between monthly rainfall and malaria mosquito populations. Results The average number of Anopheles gambiae and Anopheles funestus per trap decreased by 76.8% and 55.3%, respectively over the 1st period, and by 99.7% and 99.8% over the 2nd period. During the last year of sampling (2009), the use of 2368 traps produced a total of only 14 Anopheline mosquitoes. With the exception of the decline in An. gambiae during the 1st period, the results did not reveal any statistical association between mean trend in monthly rainfall and declining malaria vector populations. Conclusion A longitudinal decline in the density of malaria mosquito vectors was seen during both study periods despite the absence of organized vector control. Part of the decline could be associated with changes in the pattern of monthly rainfall, but other factors may also contribute to the dramatic downward trend. A similar decline in malaria vector densities could contribute to the decrease in levels of malaria infection reported from many parts of SSA. PMID:21752273

  3. Diagnosing Mechanisms of Decline and Planning for Recovery of an Endangered Brown Bear (Ursus arctos) Population

    PubMed Central

    Quenette, Pierre-Yves; Camarra, Jean-Jacques

    2009-01-01

    Background The usual paradigm for translocations is that they should not take place in declining populations until the causes(s) of the decline has been reversed. This approach sounds intuitive, but may not apply in cases where population decline is caused by behavioral or demographic mechanisms that could only be reversed by translocation itself. Methodology/Principal Findings We analyzed a decade of field data for Pyrenean brown bears (Ursus arctos) from two small populations: the growing Central population - created from a previous translocation and the endemic Western population - believed to be declining because of excessive human-caused mortality. We found that adult survival rates for both populations were as high as those observed for most other protected brown bear populations. However, the Western population had much lower reproductive success than the Central population. Adult breeding sex ratio was male-biased in the Western population and female-biased in the Central population. Our results exclude high anthropogenic mortality as a cause for population decline in the West but support low reproductive success, which could result from sexually selected infanticide induced by a male-biased adult sex ratio or inbreeding depression. Using a stochastic demographic model to compute how many bears should be released to ensure viability, we show that the Western population could recover provided adequate numbers of new females are translocated. Conclusions/Significance We suggest that a translocation could take place, even if the decline has not yet been reversed, if the translocation itself removes the biological mechanisms behind the decline. In our case, the ultimate cause of low reproductive success remained unknown (infanticide or inbreeding), but our proposed translocation strategies should eliminate the proximate cause (low reproductive success) of the decline and ensure population recovery and viability. PMID:19862319

  4. Using Latent Selection Difference to Model Persistence in a Declining Population

    PubMed Central

    Erickson, Mara E.; Found-Jackson, Christine; Boyce, Mark S.

    2014-01-01

    Population persistence is a direct measure of the viability of a population. Monitoring the distribution of declining populations or subpopulations over time can yield estimates of persistence, which we show can be modeled as a latent selection difference (LSD) contrasting attributes of sites where populations have persisted versus those that have not. Predicted persistence can be modeled with predictor covariates to identify factors correlated with species persistence. We demonstrate how to model persistence based on changes in occupancy that can include adjustments for detection probability. Using a known historical distribution of the western grebe (Aechmophorus occidentalis), we adapted methods originally developed for occupancy modeling to evaluate how environmental covariates including emergent vegetation and human developments have affected western grebe persistence in Alberta. The relative probability of persistence was correlated with the extent of shoreline bulrush (Scirpus lacustris), which is important vegetation for nesting cover. We also documented that western grebe populations were less likely to persist on lakes in the boreal forest, primarily located on the northern boundary of the species' range. Factors influencing occupancy were different than those determining persistence by western grebes; persistence and occupancy were not correlated. Persistence was more likely on lakes with recreational development, reflecting reliance by grebes on the larger, fish-bearing waterbodies that also are attractive for lakeshore development. Unfortunately, the correlation with recreational development on Alberta's lakes puts grebes at risk for loss of brood-rearing habitats—primary threats to altricial birds—if steps are not taken to prevent disturbance to bulrush stands. Identifying factors related to the persistence of a species—especially one in decline—is a fundamental step in conservation management. PMID:24866172

  5. India's fertility declines, but it still leads world in population growth.

    PubMed

    Visaria, L; Visaria, P

    1995-10-01

    Despite its fertility decline, India still has the world's second largest population size. Over the decades fertility declined to 3.6 in 1992 per woman. However great or rapid the decline, the population growth rate is an estimated 1.9% a year. Only three countries in the world have a higher rate of growth: Nigeria, Pakistan, and Bangladesh. Fertility decline is attributed to increased literacy, urbanization, industrialization, modern communication and transportation, and women's status. The availability of government family planning services has also contributed to the fertility decline. Although female literacy has risen rapidly to 39% in 1991, male literacy is still higher at 64%. Girls lag behind in school attendance in both rural and urban areas. Fertility decline has occurred faster in urban areas, which are concentrated in cities of over 100,000 people. The childbearing period has declined, and childbearing is delayed. Contraceptive usage has grown dramatically since 1970 to around 40%, depending upon the data source. Population growth is attributed to improvements in health and mortality. Life expectancy has increased to 60 years, and infant mortality declined to 74 per 1000 live births. The age structure of the population is young due to demographic changes. Growth will continue for several decades due to population momentum. India is expected to surpass China as the most populous country in the world before 2050.

  6. Population decline is linked to migration route in the Common Cuckoo

    PubMed Central

    Hewson, Chris M.; Thorup, Kasper; Pearce-Higgins, James W.; Atkinson, Philip W.

    2016-01-01

    Migratory species are in rapid decline globally. Although most mortality in long-distance migrant birds is thought to occur during migration, evidence of conditions on migration affecting breeding population sizes has been completely lacking. We addressed this by tracking 42 male Common Cuckoos from the rapidly declining UK population during 56 autumn migrations in 2011–14. Uniquely, the birds use two distinct routes to reach the same wintering grounds, allowing assessment of survival during migration independently of origin and destination. Mortality up to completion of the Sahara crossing (the major ecological barrier encountered in both routes) is higher for birds using the shorter route. The proportion of birds using this route strongly correlates with population decline across nine local breeding populations. Knowledge of variability in migratory behaviour and performance linked to robust population change data may therefore be necessary to understand population declines of migratory species and efficiently target conservation resources. PMID:27433888

  7. Population decline is linked to migration route in the Common Cuckoo.

    PubMed

    Hewson, Chris M; Thorup, Kasper; Pearce-Higgins, James W; Atkinson, Philip W

    2016-07-19

    Migratory species are in rapid decline globally. Although most mortality in long-distance migrant birds is thought to occur during migration, evidence of conditions on migration affecting breeding population sizes has been completely lacking. We addressed this by tracking 42 male Common Cuckoos from the rapidly declining UK population during 56 autumn migrations in 2011-14. Uniquely, the birds use two distinct routes to reach the same wintering grounds, allowing assessment of survival during migration independently of origin and destination. Mortality up to completion of the Sahara crossing (the major ecological barrier encountered in both routes) is higher for birds using the shorter route. The proportion of birds using this route strongly correlates with population decline across nine local breeding populations. Knowledge of variability in migratory behaviour and performance linked to robust population change data may therefore be necessary to understand population declines of migratory species and efficiently target conservation resources.

  8. Access to dental care: a historical review of medicaid eligibility growth and dental productivity decline.

    PubMed

    Kinlaw, D H

    2001-09-01

    The present dilemma in providing dental services to the indigent and Medicaid recipients throughout this nation has generated considerable controversy as to the evolution of the problem. Most states recognize that there are deficiencies in the provision of dental services to these populations and are seeking resolutions. While state licensing board practices and dental professional society politics have been the object of criticism as contributing to if not causing of this problem, other rational and statistically valid explanations for the current difficulty exist. As an explanation for access to care issues, this paper explores the decline in the national numbers of dental practitioners and concomitant dental productivity. Furthermore, it relates those parameters to the dramatic rise in the utilization and demand for dental services resulting from a robust economy, population growth trends, and changes in state and federal Medicaid legislation that increase numbers of Medicaid-eligible recipients. While these general trends are national in scope and application, the state of North Carolina and its experience will be used to fully explore the impact of these trends at the state and local level.

  9. Genomic Consequences of Population Decline in the Endangered Florida Scrub-Jay.

    PubMed

    Chen, Nancy; Cosgrove, Elissa J; Bowman, Reed; Fitzpatrick, John W; Clark, Andrew G

    2016-11-07

    Understanding the population genetic consequences of declining population size is important for conserving the many species worldwide facing severe decline [1]. Thorough empirical studies on the impacts of population reduction at a genome-wide scale in the wild are scarce because they demand huge field and laboratory investments [1, 2]. Previous studies have demonstrated the importance of gene flow in introducing genetic variation to small populations [3], but few have documented both genetic and fitness consequences of decreased immigration through time in a natural population [4-6]. Here we assess temporal variation in gene flow, inbreeding, and fitness using longitudinal genomic, demographic, and phenotypic data from a long-studied population of federally Threatened Florida scrub-jays (Aphelocoma coerulescens). We exhaustively sampled and genotyped the study population over two decades, providing one of the most detailed longitudinal investigations of genetics in a wild animal population to date. Immigrants were less heterozygous than residents but still introduced genetic variation into our study population. Owing to regional population declines, immigration into the study population declined from 1995-2013, resulting in increased levels of inbreeding and reduced fitness via inbreeding depression, even as the population remained demographically stable. Our results show that, contrary to conventional wisdom, small peripheral populations that already have undergone a genetic bottleneck may play a vital role in preserving genetic diversity of larger and seemingly stable populations. These findings underscore the importance of investing in the persistence of small populations and maintaining population connectivity in conservation of fragmented species.

  10. Replacement Migration: Is It a Solution to Declining and Ageing Populations?

    ERIC Educational Resources Information Center

    United Nations, New York, NY. Dept. of Economic and Social Affairs.

    The United Nations (UN) Population Division monitors fertility, mortality, and migration trends for all countries as a basis for producing the official UN population estimates and projections. Among recent demographic trends, two are prominent: (1) population decline and (2) population aging. Focusing on these two critical trends, a study…

  11. Replacement Migration: Is It a Solution to Declining and Ageing Populations?

    ERIC Educational Resources Information Center

    United Nations, New York, NY. Dept. of Economic and Social Affairs.

    The United Nations (UN) Population Division monitors fertility, mortality, and migration trends for all countries as a basis for producing the official UN population estimates and projections. Among recent demographic trends, two are prominent: (1) population decline and (2) population aging. Focusing on these two critical trends, a study…

  12. Do artisanal fishers perceive declining migratory shorebird populations?

    PubMed

    Andrade, Luciano Pires; Silva-Andrade, Horasa Maria Lima; Lyra-Neves, Rachel Maria; Albuquerque, Ulysses Paulino; Telino-Júnior, Wallace Rodrigues

    2016-03-03

    This paper discusses the results of ethno-ornithological research conducted on the local ecological knowledge (LEK) of artisanal fishers in northeast Brazil between August 2013 and October 2014. The present study analyzed the LEK of 240 artisanal fishermen in relation to Nearctic shorebirds and the factors that may be affecting their populations. We examined whether differences occurred according to the gender and age of the local population. The research instruments included semi-structured and check-list interviews. We found that greater knowledge of migratory birds and the areas where they occur was retained by the local men compared with the local women. Half of the male respondents stated that the birds are always in the same locations, and most of the respondents believed that changes in certain populations were caused by factors related to habitat disturbance, particularly to increases in housing construction and visitors to the island. The main practices affecting the presence of migratory birds mentioned by the locals were boat traffic and noise from bars and vessels. According to the artisanal fishermen, the population of migratory birds that use the area for foraging and resting has been reduced over time. Changes in the local landscape related to urbanization and tourism are most likely the primary causes underlying the reduced migratory shorebird populations as reported by local inhabitants. Thus, managing and monitoring urbanization and tourism are fundamental to increasing the success of the migration process and improving the conservation of migratory shorebird species.

  13. Has contemporary climate change played a role in population declines of the lizard Ctenophorus decresii from semi-arid Australia?

    PubMed

    Walker, Samantha; Stuart-Fox, Devi; Kearney, Michael R

    2015-12-01

    Whilst contemporary climatic changes are small in magnitude compared to those predicted for the coming decades, they have already been linked to species range shifts and local extinctions. Elucidating the drivers behind species' responses to contemporary climate change will better inform management strategies for vulnerable and pest species alike. A recent proposal to explain worldwide local extinctions in lizards is that increasing maximum temperatures have constrained lizard activity time in the breeding season beyond extinction thresholds. Here we document a significant population decline and potential local extinction at the warm (northern) range margin of the tawny dragon, Ctenophorus decresii, a rock-dwelling lizard from the Flinders Ranges in semi-arid Australia. We developed and tested a biophysical model of tawny dragon thermoregulatory behaviour and drove the model with daily weather data for the period 1990-2009 across the Flinders Ranges. Our results indicate that potential annual activity time has likely increased over this period throughout the historic range, with within-season declines only in the summer months at the northern range limit. However, populations that have declined since 2000 have also likely experienced higher active body temperatures and more stringent retreat-site requirements (deeper crevices) than have regions where the species remains common, during a period of declining rainfall. Our laboratory estimates of thermal preference in this species were insensitive to altered nutritional and hydric state. Thus it is possible that recent population declines are linked to desiccation stress driven by higher body temperatures and declining rainfall. Our study illustrates that simple indices of the impact of climate warming on animals, such as activity restriction, may in fact reflect a variety of potential mechanisms whose ultimate outcome will be contingent on other factors such as water and shelter availability. Copyright © 2014

  14. FACTORS IMPLICATED IN AMPHIBIAN POPULATION DECLINES IN THE UNITED STATES

    EPA Science Inventory

    Factors adversely affecting amphibian populations in the US were evaluated using information from species accounts written in a standardized format by multiple authors (Volume 2 of this book). For each species, factors implicated by the authors (i.e., known or suspected) as affec...

  15. A new method for identifying rapid decline dynamics in wild vertebrate populations

    PubMed Central

    Fonzo, Martina Di; Collen, Ben; Mace, Georgina M

    2013-01-01

    Tracking trends in the abundance of wildlife populations is a sensitive method for assessing biodiversity change due to the short time-lag between human pressures and corresponding shifts in population trends. This study tests for proposed associations between different types of human pressures and wildlife population abundance decline-curves and introduces a method to distinguish decline trajectories from natural fluctuations in population time-series. First, we simulated typical mammalian population time-series under different human pressure types and intensities and identified significant distinctions in population dynamics. Based on the concavity of the smoothed population trend and the algebraic function which was the closest fit to the data, we determined those differences in decline dynamics that were consistently attributable to each pressure type. We examined the robustness of the attribution of pressure type to population decline dynamics under more realistic conditions by simulating populations under different levels of environmental stochasticity and time-series data quality. Finally, we applied our newly developed method to 124 wildlife population time-series and investigated how those threat types diagnosed by our method compare to the specific threatening processes reported for those populations. We show how wildlife population decline curves can be used to discern between broad categories of pressure or threat types, but do not work for detailed threat attributions. More usefully, we find that differences in population decline curves can reliably identify populations where pressure is increasing over time, even when data quality is poor, and propose this method as a cost-effective technique for prioritizing conservation actions between populations. PMID:23919177

  16. Updated population metadata for United States historical climatology network stations

    USGS Publications Warehouse

    Owen, T.W.; Gallo, K.P.

    2000-01-01

    The United States Historical Climatology Network (HCN) serial temperature dataset is comprised of 1221 high-quality, long-term climate observing stations. The HCN dataset is available in several versions, one of which includes population-based temperature modifications to adjust urban temperatures for the "heat-island" effect. Unfortunately, the decennial population metadata file is not complete as missing values are present for 17.6% of the 12 210 population values associated with the 1221 individual stations during the 1900-90 interval. Retrospective grid-based populations. Within a fixed distance of an HCN station, were estimated through the use of a gridded population density dataset and historically available U.S. Census county data. The grid-based populations for the HCN stations provide values derived from a consistent methodology compared to the current HCN populations that can vary as definitions of the area associated with a city change over time. The use of grid-based populations may minimally be appropriate to augment populations for HCN climate stations that lack any population data, and are recommended when consistent and complete population data are required. The recommended urban temperature adjustments based on the HCN and grid-based methods of estimating station population can be significantly different for individual stations within the HCN dataset.

  17. Declining population immunity to mumps among Israeli military recruits.

    PubMed

    Huerta, Michael; Davidovitch, Nadav; Aboudy, Yair; Ankol, Omer E; Balicer, Ran D; Zarka, Salman; Grotto, Itamar

    2006-09-11

    Population-based seroepidemologic data on mumps have not been available in Israel since 1987, and the effects of mass immigration from the Commonwealth of Independent States during the 1990s have not been investigated. We conducted a seroprevalence study of mumps antibodies among 353 Israeli military recruits aged 18-19, based on a representative sample of sera collected in 1999. The overall seroprevalence rate was 83.3%, which was significantly lower than that measured in 1987 (94.1%, P<0.001). Foreign-born subjects had substantially lower seroporevalence rates than their native Israeli counterparts (68.5% versus 86.1%, P<0.001). Recent seroprevalence levels are below those required for herd immunity, and most likely contributed to an outbreak of mumps observed among young adults in Israel in 2005. Immigration appears to be a contributing factor to the decrease in population seroprevalence over time.

  18. Phage selection for bacterial cheats leads to population decline.

    PubMed

    Vasse, Marie; Torres-Barceló, Clara; Hochberg, Michael E

    2015-11-07

    While predators and parasites are known for their effects on bacterial population biology, their impact on the dynamics of bacterial social evolution remains largely unclear. Siderophores are iron-chelating molecules that are key to the survival of certain bacterial species in iron-limited environments, but their production can be subject to cheating by non-producing genotypes. In a selection experiment conducted over approximately 20 bacterial generations and involving 140 populations of the pathogenic bacterium Pseudomonas aeruginosa PAO1, we assessed the impact of a lytic phage on competition between siderophore producers and non-producers. We show that the presence of lytic phages favours the non-producing genotype in competition, regardless of whether iron use relies on siderophores. Interestingly, phage pressure resulted in higher siderophore production, which constitutes a cost to the producers and may explain why they were outcompeted by non-producers. By the end of the experiment, however, cheating load reduced the fitness of mixed populations relative to producer monocultures, and only monocultures of producers managed to grow in the presence of phage in situations where siderophores were necessary to access iron. These results suggest that public goods production may be modulated in the presence of natural enemies with consequences for the evolution of social strategies. © 2015 The Author(s).

  19. Demographic drivers of decline and recovery in an Afro-Palaearctic migratory bird population.

    PubMed

    Morrison, Catriona A; Robinson, Robert A; Butler, Simon J; Clark, Jacquie A; Gill, Jennifer A

    2016-11-16

    Across Europe, rapid population declines are ongoing in many Afro-Palaearctic migratory bird species, but the development of appropriate conservation actions across such large migratory ranges is severely constrained by lack of understanding of the demographic drivers of these declines. By constructing regional integrated population models (IPMs) for one of the suite of migratory species that is declining in the southeast of Britain but increasing in the northwest, we show that, while annual population growth rates in both regions vary with adult survival, the divergent regional trajectories are primarily a consequence of differences in productivity. Between 1994 and 2012, annual survival and productivity rates ranged over similar levels in both regions, but high productivity rates were rarer in the declining southeast population and never coincided with high survival rates. By contrast, population growth in the northwest was fuelled by several years in which higher productivity coincided with high survival rates. Simulated population trajectories suggest that realistic improvements in productivity could have reversed the decline (i.e. recovery of the population index to more than or equal to 1) in the southeast. Consequently, actions to improve productivity on European breeding grounds are likely to be a more fruitful and achievable means of reversing migrant declines than actions to improve survival on breeding, passage or sub-Saharan wintering grounds. © 2016 The Authors.

  20. Population declines of tuna and relatives depend on their speed of life.

    PubMed

    Juan-Jordá, M J; Mosqueira, I; Freire, J; Dulvy, N K

    2015-07-22

    Larger-bodied species in a wide range of taxonomic groups including mammals, fishes and birds tend to decline more steeply and are at greater risk of extinction. Yet, the diversity in life histories is governed not only by body size, but also by time-related traits. A key question is whether this size-dependency of vulnerability also holds, not just locally, but globally across a wider range of environments. We test the relative importance of size- and time-related life-history traits and fishing mortality in determining population declines and current exploitation status in tunas and their relatives. We use high-quality datasets of half a century of population trajectories combined with population-level fishing mortalities and life-history traits. Time-related traits (e.g. growth rate), rather than size-related traits (e.g. maximum size), better explain the extent and rate of declines and current exploitation status across tuna assemblages, after controlling for fishing mortality. Consequently, there is strong geographical patterning in population declines, such that populations with slower life histories (found at higher cooler latitudes) have declined most and more steeply and have a higher probability of being overfished than populations with faster life histories (found at tropical latitudes). Hence, the strong, temperature-driven, latitudinal gradients in life-history traits may underlie the global patterning of population declines, fisheries collapses and local extinctions. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  1. Demographic drivers of decline and recovery in an Afro-Palaearctic migratory bird population

    PubMed Central

    Robinson, Robert A.; Butler, Simon J.; Clark, Jacquie A.; Gill, Jennifer A.

    2016-01-01

    Across Europe, rapid population declines are ongoing in many Afro-Palaearctic migratory bird species, but the development of appropriate conservation actions across such large migratory ranges is severely constrained by lack of understanding of the demographic drivers of these declines. By constructing regional integrated population models (IPMs) for one of the suite of migratory species that is declining in the southeast of Britain but increasing in the northwest, we show that, while annual population growth rates in both regions vary with adult survival, the divergent regional trajectories are primarily a consequence of differences in productivity. Between 1994 and 2012, annual survival and productivity rates ranged over similar levels in both regions, but high productivity rates were rarer in the declining southeast population and never coincided with high survival rates. By contrast, population growth in the northwest was fuelled by several years in which higher productivity coincided with high survival rates. Simulated population trajectories suggest that realistic improvements in productivity could have reversed the decline (i.e. recovery of the population index to more than or equal to 1) in the southeast. Consequently, actions to improve productivity on European breeding grounds are likely to be a more fruitful and achievable means of reversing migrant declines than actions to improve survival on breeding, passage or sub-Saharan wintering grounds. PMID:27807267

  2. Population declines of tuna and relatives depend on their speed of life

    PubMed Central

    Juan-Jordá, M. J.; Mosqueira, I.; Freire, J.; Dulvy, N. K.

    2015-01-01

    Larger-bodied species in a wide range of taxonomic groups including mammals, fishes and birds tend to decline more steeply and are at greater risk of extinction. Yet, the diversity in life histories is governed not only by body size, but also by time-related traits. A key question is whether this size-dependency of vulnerability also holds, not just locally, but globally across a wider range of environments. We test the relative importance of size- and time-related life-history traits and fishing mortality in determining population declines and current exploitation status in tunas and their relatives. We use high-quality datasets of half a century of population trajectories combined with population-level fishing mortalities and life-history traits. Time-related traits (e.g. growth rate), rather than size-related traits (e.g. maximum size), better explain the extent and rate of declines and current exploitation status across tuna assemblages, after controlling for fishing mortality. Consequently, there is strong geographical patterning in population declines, such that populations with slower life histories (found at higher cooler latitudes) have declined most and more steeply and have a higher probability of being overfished than populations with faster life histories (found at tropical latitudes). Hence, the strong, temperature-driven, latitudinal gradients in life-history traits may underlie the global patterning of population declines, fisheries collapses and local extinctions. PMID:26156763

  3. Causes of mortality in California sea otters during periods of population growth and decline

    USGS Publications Warehouse

    Estes, J.A.; Hatfield, B.B.; Ralls, K.; Ames, J.

    2003-01-01

    Elevated mortality appears to be the main reason for both sluggish growth and periods of decline in the threatened California sea otter population. We assessed causes of mortality from salvage records of 3,105 beach-cast carcasses recovered from 1968 through 1999, contrasting two periods of growth with two periods of decline. Overall, an estimated 40%-60% of the deaths were not recovered and 70% of the recovered carcasses died from unknown causes. Nonetheless, several common patterns were evident in the salvage records during the periods of population decline. These included greater percentages of (1) prime age animals (3-10 yr), (2) carcasses killed by great white shark attacks, (3) carcasses recovered in spring and summer, and (4) carcasses for which the cause of death was unknown. Neither sex composition nor the proportion of carcasses dying of infectious disease varied consistently between periods of population increase and decline. The population decline from 1976 to 1984 was likely due to incidental mortality in a set-net fishery, and the decline from 1995 to 1999 may be related to a developing live-fish fishery. Long-term trends unrelated to periods of growth and decline included a decrease in per capita pup production and mass/length ratios of adult carcasses over the 31-yr study. The generally high proportion of deaths from infectious disease suggests that this factor has contributed to the chronically sluggish growth rate of the California sea otter population.

  4. Changes in land use as a possible factor in Mourning Dove population decline in Central Utah

    USGS Publications Warehouse

    Ostrand, William D.; Meyers, P.M.; Bissonette, J.A.; Conover, M.R.

    1998-01-01

    Mourning Dove (Zenaida macroura) population indices for the western United States have declined significantly since 1966. Based on data collected in 1951-1952, in Fillmore, Utah, we examined whether there had been a local decline in the dove population index since the original data were collected. We then determined whether habitat had been altered, identified which foraging habitats doves preferred, and assessed whether changes in land use could be responsible, in part, for a decline in the local population index. We found that dove population indices declined 72% and 82% from 1952-1992 and 1952-1993, respectively. The most dramatic change in habitat was an 82% decline in land devoted to dry land winter wheat production and a decline in livestock feed pens. Doves foraged primarily in harvested wheat fields, feed pens, and weedy patches. We hypothesize that a decrease in wheat availability during the spring and the consolidation of the livestock industry have contributed to a population decline of Mourning Doves in central Utah.

  5. Rapid population decline in migratory shorebirds relying on Yellow Sea tidal mudflats as stopover sites

    PubMed Central

    Studds, Colin E.; Kendall, Bruce E.; Murray, Nicholas J.; Wilson, Howard B.; Rogers, Danny I.; Clemens, Robert S.; Gosbell, Ken; Hassell, Chris J.; Jessop, Rosalind; Melville, David S.; Milton, David A.; Minton, Clive D. T.; Possingham, Hugh P.; Riegen, Adrian C.; Straw, Phil; Woehler, Eric J.; Fuller, Richard A.

    2017-01-01

    Migratory animals are threatened by human-induced global change. However, little is known about how stopover habitat, essential for refuelling during migration, affects the population dynamics of migratory species. Using 20 years of continent-wide citizen science data, we assess population trends of ten shorebird taxa that refuel on Yellow Sea tidal mudflats, a threatened ecosystem that has shrunk by >65% in recent decades. Seven of the taxa declined at rates of up to 8% per year. Taxa with the greatest reliance on the Yellow Sea as a stopover site showed the greatest declines, whereas those that stop primarily in other regions had slowly declining or stable populations. Decline rate was unaffected by shared evolutionary history among taxa and was not predicted by migration distance, breeding range size, non-breeding location, generation time or body size. These results suggest that changes in stopover habitat can severely limit migratory populations. PMID:28406155

  6. California's Youth and Young Adult Arrest Rates Continue a Historic Decline. Fact Sheet

    ERIC Educational Resources Information Center

    Males, Mike

    2016-01-01

    This Center on Juvenile and Criminal Justice (CJCJ) fact sheet shows that, in 2015, arrests of young people under age 25 dropped below 2014 levels and continue a decades-long trend of decline. While the causes of these declines are unknown, falling youth arrests rates coupled with decreased youth incarceration suggest that high rates of…

  7. Novel survey method finds dramatic decline of wild cotton-top tamarin population

    PubMed Central

    Savage, Anne; Thomas, Len; Leighty, Katherine A.; Soto, Luis H.; Medina, Felix S.

    2010-01-01

    The cotton-top tamarin (Saguinus oedipus) is a critically endangered primate, endemic to the tropical forests of Colombia. Population monitoring is essential to evaluate the success of conservation efforts, yet standard survey methods are ineffective because animals flee silently before they are seen. We developed a novel technique that combines the use of playbacks of territorial vocalizations with traditional transect surveys. We used remote sensing to identify potential habitat within the species' historic range, and visited the 27% that we could survey safely. Of this, only 99 km2 was extant forest, containing an estimated 2,045 animals (95% confidence interval 1,587–2,634). Assuming comparable densities in non-surveyed areas, approximately 7,394 wild cotton-top tamarins remain in Colombia. With 20–30,000 animals exported to the United States in the late 1960s, this must represent a precipitous decline. Habitat destruction and capture for the illegal pet trade are ongoing. Urgent conservation measures are required to prevent extinction in the wild. PMID:20975684

  8. Rapid declines of large mammal populations after the collapse of the Soviet Union.

    PubMed

    Bragina, Eugenia V; Ives, A R; Pidgeon, A M; Kuemmerle, T; Baskin, L M; Gubar, Y P; Piquer-Rodríguez, M; Keuler, N S; Petrosyan, V G; Radeloff, V C

    2015-06-01

    Anecdotal evidence suggests that socioeconomic shocks strongly affect wildlife populations, but quantitative evidence is sparse. The collapse of socialism in Russia in 1991 caused a major socioeconomic shock, including a sharp increase in poverty. We analyzed population trends of 8 large mammals in Russia from 1981 to 2010 (i.e., before and after the collapse). We hypothesized that the collapse would first cause population declines, primarily due to overexploitation, and then population increases due to adaptation of wildlife to new environments following the collapse. The long-term Database of the Russian Federal Agency of Game Mammal Monitoring, consisting of up to 50,000 transects that are monitored annually, provided an exceptional data set for investigating these population trends. Three species showed strong declines in population growth rates in the decade following the collapse, while grey wolf (Canis lupus) increased by more than 150%. After 2000 some trends reversed. For example, roe deer (Capreolus spp.) abundance in 2010 was the highest of any period in our study. Likely reasons for the population declines in the 1990s include poaching and the erosion of wildlife protection enforcement. The rapid increase of the grey wolf populations is likely due to the cessation of governmental population control. In general, the widespread declines in wildlife populations after the collapse of the Soviet Union highlight the magnitude of the effects that socioeconomic shocks can have on wildlife populations and the possible need for special conservation efforts during such times. © 2015 Society for Conservation Biology.

  9. Historical declines and disparities in cigarette coupon saving among adolescents in the United States, 1997-2013.

    PubMed

    Owotomo, Olusegun; Maslowsky, Julie; Pasch, Keryn E

    2017-07-01

    Exposure to cigarette coupons is associated with smoking initiation and likelihood of cigarette purchase among adolescents. Some adolescents who are exposed to cigarette coupons take a step further by choosing to save or collect these coupons, a further risk factor for cigarette smoking. This study examines historical trends and disparities in cigarette coupon saving among adolescents in the United States from 1997 to 2013. National samples of 10th and 12th grade students (n=129,111) were obtained from Monitoring the Future surveys in 1997-2013. Prevalence of lifetime and current cigarette coupon saving was estimated in each year in the overall adolescent population, and in race/ethnicity, parent education level, sex, and urban/rural subgroups. Prevalence of lifetime and current cigarette coupon saving was then estimated in each year based on smoking status. Prevalence of cigarette coupon saving has decreased dramatically among adolescents; only 1.2% reported currently saving coupons in 2013. However, disparities in cigarette coupon saving remain with prevalence higher among rural, White, and low parental education level students. Adolescent smokers continue to save coupons at high rates; 21.2% had ever saved coupons and 6.9% currently saved coupons as of 2013. Despite overall declines in adolescent cigarette coupon saving, existing sociodemographic disparities and the considerably high prevalence of coupon saving among adolescent smokers suggest that cigarette coupons remain a threat to smoking prevention among youth. Additional research is needed to further elucidate longitudinal associations between cigarette coupon saving and smoking initiation and maintenance among adolescents. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Beyond the disease: Is Toxoplasma gondii infection causing population declines in the eastern quoll (Dasyurus viverrinus)?

    PubMed Central

    Fancourt, Bronwyn A.; Nicol, Stewart C.; Hawkins, Clare E.; Jones, Menna E.; Johnson, Chris N.

    2014-01-01

    Disease is often considered a key threat to species of conservation significance. For some, it has resulted in localised extinctions and declines in range and abundance. However, for some species, the assertion that a disease poses a significant threat of extinction is based solely on correlative or anecdotal evidence, often inferred from individual clinical case reports. While a species’ susceptibility to a disease may be demonstrated in a number of individuals, investigations rarely extend to measuring the impact of disease at the population level and its contribution, if any, to population declines. The eastern quoll (Dasyurus viverrinus) is a medium-sized Australian marsupial carnivore that is undergoing severe and rapid decline in Tasmania, its last refuge. Reasons for the decline are currently not understood. Feral cats (Felis catus) may be undergoing competitive release following the ongoing decline of the Tasmanian devil (Sarcophilus harrisii), with cats suppressing eastern quolls through increased predation, competition, exclusion or exposure to diseases such as toxoplasmosis. To investigate the effects of Toxoplasma gondii infection, eastern quoll populations at four sites were regularly screened for the seroprevalence of T. gondii-specific IgG antibodies. Seroprevalence was approximately five times higher at sites with declining quoll populations, and there was a negative association between seroprevalence and quoll abundance. However, T. gondii infection did not reduce quoll survival or reproduction. Despite a high susceptibility to T. gondii infection, eastern quoll populations do not appear to be limited by the parasite or its resultant disease. Significantly higher seroprevalence is a signal of greater exposure to feral cats at sites where eastern quolls are declining, suggesting that increased predation, competition or exclusion by feral cats may be precipitating population declines. PMID:25161908

  11. Beyond the disease: Is Toxoplasma gondii infection causing population declines in the eastern quoll (Dasyurus viverrinus)?

    PubMed

    Fancourt, Bronwyn A; Nicol, Stewart C; Hawkins, Clare E; Jones, Menna E; Johnson, Chris N

    2014-08-01

    Disease is often considered a key threat to species of conservation significance. For some, it has resulted in localised extinctions and declines in range and abundance. However, for some species, the assertion that a disease poses a significant threat of extinction is based solely on correlative or anecdotal evidence, often inferred from individual clinical case reports. While a species' susceptibility to a disease may be demonstrated in a number of individuals, investigations rarely extend to measuring the impact of disease at the population level and its contribution, if any, to population declines. The eastern quoll (Dasyurus viverrinus) is a medium-sized Australian marsupial carnivore that is undergoing severe and rapid decline in Tasmania, its last refuge. Reasons for the decline are currently not understood. Feral cats (Felis catus) may be undergoing competitive release following the ongoing decline of the Tasmanian devil (Sarcophilus harrisii), with cats suppressing eastern quolls through increased predation, competition, exclusion or exposure to diseases such as toxoplasmosis. To investigate the effects of Toxoplasma gondii infection, eastern quoll populations at four sites were regularly screened for the seroprevalence of T. gondii-specific IgG antibodies. Seroprevalence was approximately five times higher at sites with declining quoll populations, and there was a negative association between seroprevalence and quoll abundance. However, T. gondii infection did not reduce quoll survival or reproduction. Despite a high susceptibility to T. gondii infection, eastern quoll populations do not appear to be limited by the parasite or its resultant disease. Significantly higher seroprevalence is a signal of greater exposure to feral cats at sites where eastern quolls are declining, suggesting that increased predation, competition or exclusion by feral cats may be precipitating population declines.

  12. Crab trapping causes population decline and demographic changes in diamondback terrapins over two decades

    SciTech Connect

    Dorcas, M.E., J.D. Willson and J.W. Gibbons

    2007-01-01

    Diamondback terrapins (Malaclemys terrapin) are thought to be declining throughout their range. Although many factors have been proposed to contribute to terrapin declines, including increased predation of nests and adults, habitat loss and degradation, road mortality, commercial harvest for food, and mortality as bycatch in crab traps, few studies have provided evidence linking these agents to population declines. Because male and small female terrapins are most susceptible to mortality in crab traps, population declines should coincide with shifts in the age and size distributions of the population and a shift to a more female-biased sex ratio. We used twenty-one years of mark-recapture data (>2800 captures of 1399 individuals) from a declining diamondback terrapin population in South Carolina to test the prediction that the decline is the result of mortality in crab traps. Since the 1980s, the modal size of both male and female terrapins has increased substantially and the proportion that are females is higher than in earlier samples. Additionally, the population now contains more old and fewer young individuals than before. The changes in demography and sex ratio we observed suggest that this terrapin population has declined as a result of selective mortality of smaller individuals in crab traps. The use of bycatch-reduction devices on crab traps may help prevent terrapins from entering the traps, but current models are too large to prevent mortality of males and many females in this population. Future research should focus on design and testing of effective bycatch-reduction devices for specific regions and other methods to prevent terrapin mortality in crab traps.

  13. Differential patterns of Batrachochytrium dendrobatidis infection in relict amphibian populations following severe disease-associated declines.

    PubMed

    Whitfield, Steven M; Alvarado, Gilbert; Abarca, Juan; Zumbado, Hector; Zuñiga, Ibrahim; Wainwright, Mark; Kerby, Jacob

    2017-09-20

    Global amphibian biodiversity has declined dramatically in the past 4 decades, and many amphibian species have declined to near extinction as a result of emergence of the amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd). However, persistent or recovering populations of several amphibian species have recently been rediscovered, and such populations may illustrate how amphibian species that are highly susceptible to chytridiomycosis may survive in the presence of Bd. We conducted field surveys for Bd infection in 7 species of Costa Rican amphibians (all species that have declined to near extinction but for which isolated populations persist) to characterize infection profiles in highly Bd-susceptible amphibians post-decline. We found highly variable patterns in infection, with some species showing low prevalence (~10%) and low infection intensity and others showing high infection prevalence (>80%) and either low or high infection intensity. Across sites, infection rates were negatively associated with mean annual precipitation, and infection intensity across sites was negatively associated with mean average temperatures. Our results illustrate that even the most Bd-susceptible amphibians can persist in Bd-enzootic ecosystems, and that multiple ecological or evolutionary mechanisms likely exist for host-pathogen co-existence between Bd and the most Bd-susceptible amphibian species. Continued monitoring of these populations is necessary to evaluate population trends (continuing decline, stability, or population growth). These results should inform efforts to mitigate impacts of Bd on amphibians in the field.

  14. Declines in migrant shorebird populations from a winter-quarter perspective.

    PubMed

    Simmons, Robert E; Kolberg, Holger; Braby, Rod; Erni, Birgit

    2015-06-01

    Many long-distance migrating shorebird (i.e., sandpipers, plovers, flamingos, oystercatchers) populations are declining. Although regular shorebird monitoring programs exist worldwide, most estimates of shorebird population trends and sizes are poor or nonexistent. We built a state-space model to estimate shorebird population trends. Compared with more commonly used methods of trend estimation, state-space models are more mechanistic, allow for the separation of observation and state process, and can easily accommodate multivariate time series and nonlinear trends. We fitted the model to count data collected from 1990 to 2013 on 18 common shorebirds at the 2 largest coastal wetlands in southern Africa, Sandwich Harbour (a relatively pristine bay) and Walvis Bay (an international harbor), Namibia. Four of the 12 long-distance migrant species declined since 1990: Ruddy Turnstone (Arenaria interpres), Little Stint (Calidris minuta), Common Ringed Plover (Charadrius hiaticula), and Red Knot (Calidris canutus). Populations of resident species and short-distance migrants increased or were stable. Similar patterns at a key South African wetland suggest that shorebird populations migrating to southern Africa are declining in line with the global decline, but local conditions in southern Africa's largest wetlands are not contributing to these declines. State-space models provide estimates of population levels and trends and could be used widely to improve the current state of water bird estimates. © 2015 Society for Conservation Biology.

  15. Decline of the Black Tern (Chlidonias niger) population in the Klamath Basin, Oregon, 2001-2010

    Treesearch

    Jaime L. Stephens; Sarah M. Rockwell; C. John Ralph; John D Alexander

    2015-01-01

    We monitored the Black Tern (Childonias niger) population at Agency and Upper Klamath Lakes, in the Klamath Basin, Oregon, from 2001–2010. We estimated that the population of adult Black Terns declined at these 2 joined waterbodies by 8.4% annually. In contrast, our analysis of Breeding Bird Survey data for the Bird...

  16. Growing hickories (Carya spp.) for roost trees: A method to support conservation of declining bat populations

    Treesearch

    Tara Luna; Daniel L. Lindner; R. Kasten Dumroese

    2014-01-01

    Bats (Vespertilionidae and Phyllostomidae) are a critically important component of North American ecosystems. These insectivorous mammals provide largely unrecognized ecosystem services to agriculture and forest health and sustain bat-dependent native plant populations. The decline of North American bat populations reflects the recent emergence of the fungal disease...

  17. DNA evidence for historic population size and past ecosystem impacts of gray whales

    PubMed Central

    Alter, S. Elizabeth; Rynes, Eric; Palumbi, Stephen R.

    2007-01-01

    Ecosystem restoration may require returning threatened populations of ecologically pivotal species to near their former abundances, but it is often difficult to estimate historic population size of species that have been heavily exploited. Eastern Pacific gray whales play a key ecological role in their Arctic feeding grounds and are widely thought to have returned to their prewhaling abundance. Recent mortality spikes might signal that the population has reached long-term carrying capacity, but an alternative is that this decline was due to shifting climatic conditions on Arctic feeding grounds. We used a genetic approach to estimate prewhaling abundance of gray whales and report DNA variability at 10 loci that is typical of a population of ≈76,000–118,000 individuals, approximately three to five times more numerous than today's average census size of 22,000. Coalescent simulations indicate these estimates may include the entire Pacific metapopulation, suggesting that our average measurement of ≈96,000 individuals was probably distributed between the eastern and currently endangered western Pacific populations. These levels of genetic variation suggest the eastern population is at most at 28–56% of its historical abundance and should be considered depleted. If used to inform management, this would halve acceptable human-caused mortality for this population from 417 to 208 per year. Potentially profound ecosystem impacts may have resulted from a decline from 96,000 gray whales to the current population. At previous levels, gray whales may have seasonally resuspended 700 million cubic meters of sediment, as much as 12 Yukon Rivers, and provided food to a million sea birds. PMID:17848511

  18. DNA evidence for historic population size and past ecosystem impacts of gray whales.

    PubMed

    Alter, S Elizabeth; Rynes, Eric; Palumbi, Stephen R

    2007-09-18

    Ecosystem restoration may require returning threatened populations of ecologically pivotal species to near their former abundances, but it is often difficult to estimate historic population size of species that have been heavily exploited. Eastern Pacific gray whales play a key ecological role in their Arctic feeding grounds and are widely thought to have returned to their prewhaling abundance. Recent mortality spikes might signal that the population has reached long-term carrying capacity, but an alternative is that this decline was due to shifting climatic conditions on Arctic feeding grounds. We used a genetic approach to estimate prewhaling abundance of gray whales and report DNA variability at 10 loci that is typical of a population of approximately 76,000-118,000 individuals, approximately three to five times more numerous than today's average census size of 22,000. Coalescent simulations indicate these estimates may include the entire Pacific metapopulation, suggesting that our average measurement of approximately 96,000 individuals was probably distributed between the eastern and currently endangered western Pacific populations. These levels of genetic variation suggest the eastern population is at most at 28-56% of its historical abundance and should be considered depleted. If used to inform management, this would halve acceptable human-caused mortality for this population from 417 to 208 per year. Potentially profound ecosystem impacts may have resulted from a decline from 96,000 gray whales to the current population. At previous levels, gray whales may have seasonally resuspended 700 million cubic meters of sediment, as much as 12 Yukon Rivers, and provided food to a million sea birds.

  19. Rise and decline of an urban conscience: urban environments, recreation, and historic preservation

    SciTech Connect

    Strong, A.L.

    1984-01-01

    A review of the major demographic trends that have led to the urban pattern of settlement examines the historic links of the urban aesthetic with the nation's past. It also examines the political constituency of urban areas from the Supreme Court, the changing philosophies of presidents, and the rise of the urban conscience in urban growth policies, new towns, and urban recreation, including the national seashore, wilderness reserves, and aid for open space. Historic preservation programs are the one exception to a poor performance of most federal programs. The administration favors them because a small federal expenditure leverages substantial private-sector spending.

  20. Range-wide distribution of genetic diversity in the North American tree Juglans cinerea: a product of range shifts, not ecological marginality or recent population decline.

    PubMed

    Hoban, Sean M; Borkowski, Daniel S; Brosi, Sunshine L; McCleary, Tim S; Thompson, Laura M; McLachlan, Jason S; Pereira, Marie A; Schlarbaum, Scott E; Romero-Severson, Jeanne

    2010-11-01

    The spatial distribution of genetic diversity is a product of recent and historical ecological processes, as well as anthropogenic activities. A current challenge in population and conservation genetics is to disentangle the relative effects of these processes, as a first step in predicting population response to future environmental change. In this investigation, we compare the influence of contemporary population decline, contemporary ecological marginality and postglacial range shifts. Using classical model comparison procedures and Bayesian methods, we have identified postglacial range shift as the clear determinant of genetic diversity, differentiation and bottlenecks in 29 populations of butternut, Juglans cinerea L., a North American outcrossing forest tree. Although butternut has experienced dramatic 20th century decline because of an introduced fungal pathogen, our analysis indicates that recent population decline has had less genetic impact than postglacial recolonization history. Location within the range edge vs. the range core also failed to account for the observed patterns of diversity and differentiation. Our results suggest that the genetic impact of large-scale recent population losses in forest trees should be considered in the light of Pleistocene-era large-scale range shifts that may have had long-term genetic consequences. The data also suggest that the population dynamics and life history of wind-pollinated forest trees may provide a buffer against steep population declines of short duration, a result having important implications for habitat management efforts, ex situ conservation sampling and population viability analysis. © 2010 Blackwell Publishing Ltd.

  1. Climate and ecosystem linkages explain widespread declines in North American Atlantic salmon populations.

    PubMed

    Mills, Katherine E; Pershing, Andrew J; Sheehan, Timothy F; Mountain, David

    2013-10-01

    North American Atlantic salmon (Salmo salar) populations experienced substantial declines in the early 1990s, and many populations have persisted at low abundances in recent years. Abundance and productivity declined in a coherent manner across major regions of North America, and this coherence points toward a potential shift in marine survivorship, rather than local, river-specific factors. The major declines in Atlantic salmon populations occurred against a backdrop of physical and biological shifts in Northwest Atlantic ecosystems. Analyses of changes in climate, physical, and lower trophic level biological factors provide substantial evidence that climate conditions directly and indirectly influence the abundance and productivity of North American Atlantic salmon populations. A major decline in salmon abundance after 1990 was preceded by a series of changes across multiple levels of the ecosystem, and a subsequent population change in 1997, primarily related to salmon productivity, followed an unusually low NAO event. Pairwise correlations further demonstrate that climate and physical conditions are associated with changes in plankton communities and prey availability, which are ultimately linked to Atlantic salmon populations. Results suggest that poor trophic conditions, likely due to climate-driven environmental factors, and warmer ocean temperatures throughout their marine habitat area are constraining the productivity and recovery of North American Atlantic salmon populations. © 2013 John Wiley & Sons Ltd.

  2. Distribution-wide effects of climate on population densities of a declining migratory landbird.

    PubMed

    Anders, Angela D; Post, Eric

    2006-01-01

    1. Increases in global temperatures have created concern about effects of climatic variability on populations, and climate has been shown to affect population dynamics in an increasing number of species. Testing for effects of climate on population densities across a species' distribution allows for elucidation of effects of climate that would not be apparent at smaller spatial scales. 2. Using autoregressive population models, we tested for effects of the North Atlantic Oscillation (NAO) and the El Niño Southern Oscillation (ENSO) on annual population densities of a North American migratory landbird, the yellow-billed cuckoo Coccyzus americanus, across the species' breeding distribution over a 37-year period (1966-2002). 3. Our results indicate that both the NAO and ENSO have affected population densities of C. americanus across much of the species' breeding range, with the strongest effects of climate in regions in which these climate systems have the strongest effects on local temperatures. Analyses also indicate that the strength of the effect of local temperatures on C. americanus populations was predictive of long-term population decline, with populations that were more negatively affected by warm temperatures experiencing steeper declines. 4. Results of this study highlight the importance of distribution-wide analyses of climatic effects and demonstrate that increases in global temperatures have the potential to lead to additional population declines.

  3. Extinction rate, historical population structure and ecological role of the Caribbean monk seal

    PubMed Central

    McClenachan, Loren; Cooper, Andrew B

    2008-01-01

    The productivity and biomass of pristine coral reef ecosystems is poorly understood, particularly in the Caribbean where communities have been impacted by overfishing and multiple other stressors over centuries. Using historical data on the spatial distribution and abundance of the extinct Caribbean monk seal (Monachus tropicalis), this study reconstructs the population size, structure and ecological role of this once common predator within coral reef communities, and provides evidence that historical reefs supported biomasses of fishes and invertebrates up to six times greater than those found on typical modern Caribbean reefs. An estimated 233 000–338 000 monk seals were distributed among 13 colonies across the Caribbean. The biomass of reef fishes and invertebrates required to support historical seal populations was 732–1018 g m−2 of reefs, which exceeds that found on any Caribbean reef today and is comparable with those measured in remote Pacific reefs. Quantitative estimates of historically dense monk seal colonies and their consumption rates on pristine reefs provide concrete data on the magnitude of decline in animal biomass on Caribbean coral reefs. Realistic reconstruction of these past ecosystems is critical to understanding the profound and long-lasting effect of human hunting on the functioning of coral reef ecosystems. PMID:18348965

  4. The Declining Significance of Historically Black Colleges and Universities: Relevance, Reputation, and Reality in Obamamerica

    ERIC Educational Resources Information Center

    Brown, M. Christopher, II

    2013-01-01

    Historically Black colleges and universities are a unique institutional cohort in American higher education. These colleges have been celebrated for their achievements and critiqued for their composition at differing points during their collective history. This article addresses contemporary ebbs and flows of their relevance and reputation in the…

  5. Emerging infectious diseases of wildlife: role in amphibian population declines and global implications

    USGS Publications Warehouse

    Daszak, P.; Berger, Lee; Cunningham, A.A.; Hyatt, A.D.; Green, D.E.; Speare, R.

    1999-01-01

    We review recent research on the pathology, ecology, and biogeography of two emerging infectious wildlife diseases, chytridiomycosis and ranaviral disease, in the context of host-parasite population biology. We examine the role of these diseases in the global decline of amphibian populations and propose hypotheses for the origins and impact of these panzootics. Finally, we discuss emerging infectious diseases as a global threat to wildlife populations.

  6. Mountain gorilla genomes reveal the impact of long-term population decline and inbreeding.

    PubMed

    Xue, Yali; Prado-Martinez, Javier; Sudmant, Peter H; Narasimhan, Vagheesh; Ayub, Qasim; Szpak, Michal; Frandsen, Peter; Chen, Yuan; Yngvadottir, Bryndis; Cooper, David N; de Manuel, Marc; Hernandez-Rodriguez, Jessica; Lobon, Irene; Siegismund, Hans R; Pagani, Luca; Quail, Michael A; Hvilsom, Christina; Mudakikwa, Antoine; Eichler, Evan E; Cranfield, Michael R; Marques-Bonet, Tomas; Tyler-Smith, Chris; Scally, Aylwyn

    2015-04-10

    Mountain gorillas are an endangered great ape subspecies and a prominent focus for conservation, yet we know little about their genomic diversity and evolutionary past. We sequenced whole genomes from multiple wild individuals and compared the genomes of all four Gorilla subspecies. We found that the two eastern subspecies have experienced a prolonged population decline over the past 100,000 years, resulting in very low genetic diversity and an increased overall burden of deleterious variation. A further recent decline in the mountain gorilla population has led to extensive inbreeding, such that individuals are typically homozygous at 34% of their sequence, leading to the purging of severely deleterious recessive mutations from the population. We discuss the causes of their decline and the consequences for their future survival. Copyright © 2015, American Association for the Advancement of Science.

  7. Mountain gorilla genomes reveal the impact of long-term population decline and inbreeding

    PubMed Central

    Ayub, Qasim; Szpak, Michal; Frandsen, Peter; Chen, Yuan; Yngvadottir, Bryndis; Cooper, David N.; de Manuel, Marc; Hernandez-Rodriguez, Jessica; Lobon, Irene; Siegismund, Hans R.; Pagani, Luca; Quail, Michael A.; Hvilsom, Christina; Mudakikwa, Antoine; Eichler, Evan E.; Cranfield, Michael R.; Marques-Bonet, Tomas; Tyler-Smith, Chris; Scally, Aylwyn

    2015-01-01

    Mountain gorillas are an endangered great ape subspecies and a prominent focus for conservation, yet we know little about their genomic diversity and evolutionary past. We sequenced whole genomes from multiple wild individuals and compared the genomes of all four Gorilla subspecies. We found that the two eastern subspecies have experienced a prolonged population decline over the past 100,000 years, resulting in very low genetic diversity and an increased overall burden of deleterious variation. A further recent decline in the mountain gorilla population has led to extensive inbreeding, such that individuals are typically homozygous at 34% of their sequence, leading to the purging of severely deleterious recessive mutations from the population. We discuss the causes of their decline and the consequences for their future survival. PMID:25859046

  8. Population declines in North American birds that migrate to the neotropics

    USGS Publications Warehouse

    Robbins, C.S.; Sauer, J.R.; Greenberg, R.S.; Droege, S.

    1989-01-01

    Using data from the North American Breeding Bird Survey, we determined that most neotropical migrant bird species that breed in forests of the eastern United States and Canada have recently (1978-1987) declined in abundance after a period of stable or increasing populations. Most permanent residents and temperate-zone migrants did not show a general pattern of decrease during this period. Field data from Mexico were used to classify a subset of the neotropical migrants as using forest or scrub habitats during winter. Population declines during 1978-1987 were significantly greater among the forest-wintering species, while populations of scrub-wintering species increased. The same subset of neotropical migrants also showed overall declines in forest-breeding species, but no significant differences existed between species breeding in forest and scrub habitats. Neotropical migrant species that primarily use forested habitats in either wintering or breeding areas are declining, but a statistically significant association between habitat and population declines was detected only in the tropics.

  9. Genomic signatures of population decline in the malaria mosquito Anopheles gambiae.

    PubMed

    O'Loughlin, Samantha M; Magesa, Stephen M; Mbogo, Charles; Mosha, Franklin; Midega, Janet; Burt, Austin

    2016-03-24

    Population genomic features such as nucleotide diversity and linkage disequilibrium are expected to be strongly shaped by changes in population size, and might therefore be useful for monitoring the success of a control campaign. In the Kilifi district of Kenya, there has been a marked decline in the abundance of the malaria vector Anopheles gambiae subsequent to the rollout of insecticide-treated bed nets. To investigate whether this decline left a detectable population genomic signature, simulations were performed to compare the effect of population crashes on nucleotide diversity, Tajima's D, and linkage disequilibrium (as measured by the population recombination parameter ρ). Linkage disequilibrium and ρ were estimated for An. gambiae from Kilifi, and compared them to values for Anopheles arabiensis and Anopheles merus at the same location, and for An. gambiae in a location 200 km from Kilifi. In the first simulations ρ changed more rapidly after a population crash than the other statistics, and therefore is a more sensitive indicator of recent population decline. In the empirical data, linkage disequilibrium extends 100-1000 times further, and ρ is 100-1000 times smaller, for the Kilifi population of An. gambiae than for any of the other populations. There were also significant runs of homozygosity in many of the individual An. gambiae mosquitoes from Kilifi. These results support the hypothesis that the recent decline in An. gambiae was driven by the rollout of bed nets. Measuring population genomic parameters in a small sample of individuals before, during and after vector or pest control may be a valuable method of tracking the effectiveness of interventions.

  10. Terminal decline of episodic memory and perceptual speed in a biracial population.

    PubMed

    Wilson, Robert S; Rajan, Kumar B; Barnes, Lisa L; Jansen, Willemijn; Amofa, Priscilla; Weuve, Jennifer; Evans, Denis A

    2017-03-23

    We compared trajectories of terminal cognitive decline in older Black (n = 3372) and White (n = 1756) persons from a defined population who completed tests of episodic memory and perceptual speed at 3-year intervals for up to 18 years. During a mean of 9.9 years of observation, 1608 Black persons and 902 White persons died. Preterminal decline of episodic memory did not differ by race. Terminal episodic memory decline began earlier in Black persons (mean of 4.3 years before death) than in White persons (mean = 3.9 years) and progressed more slowly. By contrast, terminal decline of perceptual speed began earlier in White persons (mean = 5.0 years) than in Black persons (mean = 4.5 years). Rate of perceptual speed decline was more rapid in White persons than in Black persons in both the preterminal and terminal periods. The results indicate that terminal cognitive decline occurs in Black persons but suggest that the rate of cognitive decline during the terminal period is less rapid in Black persons than in White persons.

  11. Population dynamics of American horseshoe crabs--historic climatic events and recent anthropogenic pressures.

    PubMed

    Faurby, Søren; King, Tim L; Obst, Matthias; Hallerman, Eric M; Pertoldi, Cino; Funch, Peter

    2010-08-01

    Populations of the American horseshoe crab, Limulus polyphemus, have declined, but neither the causes nor the magnitude are fully understood. In order to evaluate historic demography, variation at 12 microsatellite DNA loci surveyed in 1218 L. polyphemus sampled from 28 localities was analysed with Bayesian coalescent-based methods. The analysis showed strong declines in population sizes throughout the species' distribution except in the geographically isolated southern-most population in Mexico, where a strong increase in population size was inferred. Analyses suggested that demographic changes in the core of the distribution occurred in association with the recolonization after the Ice Age and also by anthropogenic effects, such as the past overharvest of the species for fertilizer or the current use of the animals as bait for American eel (Anguilla rostrata) and whelk (Busycon spp.) fisheries. This study highlights the importance of considering both climatic changes and anthropogenic effects in efforts to understand population dynamics--a topic which is highly relevant in the ongoing assessments of the effects of climate change and overharvest.

  12. Population dynamics of American horseshoe crabs-historic climatic events and recent anthropogenic pressures

    USGS Publications Warehouse

    Faurby, S.; King, T.L.; Obst, M.; Hallerman, E.M.; Pertoldi, C.; Funch, P.

    2010-01-01

    Populations of the American horseshoe crab, Limulus polyphemus, have declined, but neither the causes nor the magnitude are fully understood. In order to evaluate historic demography, variation at 12 microsatellite DNA loci surveyed in 1218 L. polyphemus sampled from 28 localities was analysed with Bayesian coalescent-based methods. The analysis showed strong declines in population sizes throughout the species' distribution except in the geographically isolated southern-most population in Mexico, where a strong increase in population size was inferred. Analyses suggested that demographic changes in the core of the distribution occurred in association with the recolonization after the Ice Age and also by anthropogenic effects, such as the past overharvest of the species for fertilizer or the current use of the animals as bait for American eel (Anguilla rostrata) and whelk (Busycon spp.) fisheries. This study highlights the importance of considering both climatic changes and anthropogenic effects in efforts to understand population dynamics-a topic which is highly relevant in the ongoing assessments of the effects of climate change and overharvest. ?? 2010 Blackwell Publishing Ltd.

  13. Direct evidence for the role of pesticides in amphibian population declines in the Sierra Nevada Mountains, California, USA

    USDA-ARS?s Scientific Manuscript database

    For 20 years, conservationists have agreed that amphibian populations around the world are declining. Proposed causes of these declines include habitat loss, environmental contaminants, disease, introduced predators, global climate change, and others. Substantial but indirect evidence through labo...

  14. Risk factors for FEV1 decline in mild COPD and high-risk populations

    PubMed Central

    Chen, Shujing; Wang, Changhui; Li, Bing; Shi, Guochao; Li, Huiping; Zhang, Jing; Gu, Yutong; Zhou, Jian; Song, Yuanlin; Bai, Chunxue

    2017-01-01

    Background Early diagnosis of COPD is often not achieved due to limited recognition and limited access to the pulmonary function test. Our hypothesis was that lung function decline may be different between populations with mild COPD and those who are at high risk and do not receive treatment. Patients and methods Subjects with mild COPD and those from a high-risk COPD population were recruited from a community-based COPD epidemiological study after obtaining consent. Baseline clinical characteristics, symptom questionnaire, spirometry, low-dose computed tomography (LDCT) chest scan, and blood plasma biomarker data were collected initially and then 1 year later. Results A total of 617 participants were recruited, and 438 eventually completed the first-year follow-up visit; 72 participants (46 males) were in the mild COPD group, and 225 participants (165 males) were in the high-risk group. The mean forced expiratory volume in the first second of expiration (FEV1) decline in the mild COPD group was 129 mL, which was significantly higher than the 30 mL decline in the high-risk population group (P=0.005). Group category (odds ratio [OR] =0.230) and COPD Assessment Test (CAT) score (OR =9.912) were independent risk factors for an FEV1% predicted decline of >15% for all participants. In the mild COPD group, patients with a higher CAT (OR =5.310) and Emphysema Index (OR =5.681) were associated with a FEV1% predicted decline of >15% at the first-year follow-up. No factor showed a significantly predictive effect on FEV1 decline in the high-risk COPD group. Conclusion Group category was an independent influential factor associated with FEV1 decline. PMID:28184155

  15. Diclofenac poisoning is widespread in declining vulture populations across the Indian subcontinent.

    PubMed Central

    Shultz, Susanne; Baral, Hem Sagar; Charman, Sheonaidh; Cunningham, Andrew A; Das, Devojit; Ghalsasi, G R; Goudar, Mallikarjun S; Green, Rhys E; Jones, Ainsley; Nighot, Prashant; Pain, Deborah J; Prakash, Vibhu

    2004-01-01

    Recent declines in the populations of three species of vultures in the Indian subcontinent are among the most rapid ever recorded in any bird species. Evidence from a previous study of one of these species, Gyps bengalensis, in the Punjab province of Pakistan, strongly implicates mortality caused by ingestion of residues of the veterinary non-steroidal anti-inflammatory drug diclofenac as the major cause of the decline. We show that a high proportion of Gyps bengalensis and G. indicus found dead or dying in a much larger area of India and Nepal also have residues of diclofenac and visceral gout, a post-mortem finding that is strongly associated with diclofenac contamination in both species. Hence, veterinary use of diclofenac is likely to have been the major cause of the rapid vulture population declines across the subcontinent. PMID:15801603

  16. Investigating Rates of Hunting and Survival in Declining European Lapwing Populations

    PubMed Central

    2016-01-01

    Understanding effects of harvest on population dynamics is of major interest, especially for declining species. European lapwing Vanellus vanellus populations increased from the 1960s until the 1980s and declined strongly thereafter. About 400,000 lapwings are harvested annually and it is thus of high conservation relevance to assess whether hunting was a main cause for the observed changes in lapwing population trends. We developed a multi-event cause-specific mortality model which we applied to a long-term ring-recovery data set (1960–2010) of > 360,000 records to estimate survival and cause-specific mortalities. We found no temporal change in survival over the last 50 years for first-year (FY) and older birds (after first-year; AFY) originating from different ringing areas. Mean survival was high, around 0.60 and 0.80 for FY and AFY individuals, respectively. The proportion of total mortality due to hunting was <0.10 over the study period and the estimated proportion of harvested individuals (kill rate) was <0.05 in each year. Our result of constant survival indicates that demographic processes other than survival were responsible for the pronounced change in lapwing population trends in the 1980s. Our findings lend support to the hypothesis that hunting was not a significant contributor to the large-scale decline of lapwing populations. To halt the ongoing decline of European lapwing populations management should focus on life history stages other than survival (e.g. productivity). Further analyses are required to investigate the contribution of other demographic rates to the decline of lapwings and to identify the most efficient conservation actions. PMID:27685660

  17. Decline of recent seabirds inferred from a composite 1000-year record of population dynamics

    PubMed Central

    Xu, Liqiang; Liu, Xiaodong; Wu, Libin; Sun, Liguang; Zhao, Jinjun; Chen, Lin

    2016-01-01

    Based on three ornithogenic sediment profiles and seabird subfossils therein from the Xisha Islands, South China Sea, the relative population size of seabirds over the past 1000 years was reconstructed using reflectance spectrum. Here we present an apparent increase and subsequent decline of seabirds on these islands in the South China Sea. Seabird populations peaked during the Little Ice Age (LIA, 1400–1850 AD), implying that the cool climate during the LIA appears to have been more favorable to seabirds on the Xisha Islands in the South China Sea. Climate change partly explains the recent decrease in seabird populations over the past 150 years, but the significant decline and almost complete disappearance thereof on most of the Xisha Islands is probably attributable to human disturbance. Our study reveals the increasing impact of anthropogenic activities on seabird population in recent times. PMID:27748366

  18. Decline of recent seabirds inferred from a composite 1000-year record of population dynamics

    NASA Astrophysics Data System (ADS)

    Xu, Liqiang; Liu, Xiaodong; Wu, Libin; Sun, Liguang; Zhao, Jinjun; Chen, Lin

    2016-10-01

    Based on three ornithogenic sediment profiles and seabird subfossils therein from the Xisha Islands, South China Sea, the relative population size of seabirds over the past 1000 years was reconstructed using reflectance spectrum. Here we present an apparent increase and subsequent decline of seabirds on these islands in the South China Sea. Seabird populations peaked during the Little Ice Age (LIA, 1400–1850 AD), implying that the cool climate during the LIA appears to have been more favorable to seabirds on the Xisha Islands in the South China Sea. Climate change partly explains the recent decrease in seabird populations over the past 150 years, but the significant decline and almost complete disappearance thereof on most of the Xisha Islands is probably attributable to human disturbance. Our study reveals the increasing impact of anthropogenic activities on seabird population in recent times.

  19. Declines in low-elevation subalpine tree populations outpace growth in high-elevation populations with warming

    USGS Publications Warehouse

    Conlisk, Erin; Castanha, Cristina; Germino, Matthew J.; Veblen, Thomas T; Smith, Jeremy M.; Kueppers, Lara M.

    2017-01-01

    Species distribution shifts in response to climate change require that recruitment increase beyond current range boundaries. For trees with long life spans, the importance of climate-sensitive seedling establishment to the pace of range shifts has not been demonstrated quantitatively.Using spatially explicit, stochastic population models combined with data from long-term forest surveys, we explored whether the climate-sensitivity of recruitment observed in climate manipulation experiments was sufficient to alter populations and elevation ranges of two widely distributed, high-elevation North American conifers.Empirically observed, warming-driven declines in recruitment led to rapid modelled population declines at the low-elevation, ‘warm edge’ of subalpine forest and slow emergence of populations beyond the high-elevation, ‘cool edge’. Because population declines in the forest occurred much faster than population emergence in the alpine, we observed range contraction for both species. For Engelmann spruce, this contraction was permanent over the modelled time horizon, even in the presence of increased moisture. For limber pine, lower sensitivity to warming may facilitate persistence at low elevations – especially in the presence of increased moisture – and rapid establishment above tree line, and, ultimately, expansion into the alpine.Synthesis. Assuming 21st century warming and no additional moisture, population dynamics in high-elevation forests led to transient range contractions for limber pine and potentially permanent range contractions for Engelmann spruce. Thus, limitations to seedling recruitment with warming can constrain the pace of subalpine tree range shifts.

  20. An historical sketch of the American population control movement.

    PubMed

    Mass, B

    1974-01-01

    The fundamental premises and historical development of the American population control movement are critically examined from the Marxist viewpoint. It is initially shown how the Malthusian theories of population growth became interwoven with those of the eugenics movement during the first 4 decades of the 20th century. After World War II, the concern of eugenicists with race betterment and with halting the growth in numbers of the "unfit" was superseded by claims that the world was gravely menaced by a "population explosion." Subsequently, it is shown how American financiers and industrialists became leading figures of the "Population Establishment" and promoted private and public funding for support of population control activities. The uneven growth in the 1950's and the rapid growth in the 1960's of United States' efforts to promote domestic and international family planning activities are described at length. Activities of UN agencies and of United States Government agencies, particularly the activities of the Agency for International Development, are emphasized. A description of events connected with World Population Year notes the opposition of many developing countries to what they regard as an overemphasis upon birth control divorced from broad programs of social and economic development. The alleged economic exploitation of capitalism is regarded as a fundamental roadblock to intelligent family planning. Thus, talk of the population bomb merely masks the need to eliminate capitalism and proceed with an equitable distribution of the world's resources.

  1. Living on the edge: disease, population decline and conservation efforts of the Florida torreya (Torreya taxifolia)"

    USDA-ARS?s Scientific Manuscript database

    Florida torreya, Torreya taxifolia, has experienced a dramatic and precipitous population decline in its native habitat in ravines along the Apalachicola River over the past century. Recent studies have demonstrated that a novel fungal pathogen,Fusarium torreyae, is causing a severe canker and dieba...

  2. Pesticide Distributions and Population Declines of California Alpine Frogs, Rana Muscosa and Rana Sierrae

    EPA Science Inventory

    Atmospherically deposited pesticides from the intensively cultivated Central Valley of California have been implicated as a cause for population declines of several amphibian species, with the strongest evidence for the frogs Rana muscosa and Rana sierrae at high elevation in th...

  3. Recent population decline of the Marbled Murrelet in the Pacific Northwest

    Treesearch

    Sherri L. Miller; Martin G. Raphael; Gary A. Falxa; Craig Strong; Jim Baldwin; Thomas Bloxton; Beth M. Galleher; Monique Lance; Deanna Lynch; Scott F. Pearson; C. John Ralph; Richard D. Young

    2012-01-01

    We document here a decline of nearly 30% in the Marbled Murrelet (Brachyramphus marmoratus) population of Washington, Oregon, and northern California between 2000 and 2010. The Northwest Forest Plan is an ecosystem-management plan for federal forest lands in the Pacific Northwest of the United States that incorporates monitoring to determine if...

  4. Pesticide distributions and population declines of California alpine frogs, Rana muscosa and Rana sierrae

    USDA-ARS?s Scientific Manuscript database

    Atmospherically deposited pesticides from the intensively cultivated Central Valley of California have been implicated as a cause for population declines of several amphibian species, with the strongest evidence for the frogs, Rana muscosa and Rana sierrae at high elevation in the Sierra Nevada moun...

  5. Pesticide Distributions and Population Declines of California Alpine Frogs, Rana Muscosa and Rana Sierrae

    EPA Science Inventory

    Atmospherically deposited pesticides from the intensively cultivated Central Valley of California have been implicated as a cause for population declines of several amphibian species, with the strongest evidence for the frogs Rana muscosa and Rana sierrae at high elevation in th...

  6. Rapid Global Expansion of the Fungal Disease Chytridiomycosis into Declining and Healthy Amphibian Populations

    PubMed Central

    James, Timothy Y.; Litvintseva, Anastasia P.; Vilgalys, Rytas; Morgan, Jess A. T.; Taylor, John W.; Fisher, Matthew C.; Berger, Lee; Weldon, Ché; du Preez, Louis; Longcore, Joyce E.

    2009-01-01

    The fungal disease chytridiomycosis, caused by Batrachochytrium dendrobatidis, is enigmatic because it occurs globally in both declining and apparently healthy (non-declining) amphibian populations. This distribution has fueled debate concerning whether, in sites where it has recently been found, the pathogen was introduced or is endemic. In this study, we addressed the molecular population genetics of a global collection of fungal strains from both declining and healthy amphibian populations using DNA sequence variation from 17 nuclear loci and a large fragment from the mitochondrial genome. We found a low rate of DNA polymorphism, with only two sequence alleles detected at each locus, but a high diversity of diploid genotypes. Half of the loci displayed an excess of heterozygous genotypes, consistent with a primarily clonal mode of reproduction. Despite the absence of obvious sex, genotypic diversity was high (44 unique genotypes out of 59 strains). We provide evidence that the observed genotypic variation can be generated by loss of heterozygosity through mitotic recombination. One strain isolated from a bullfrog possessed as much allelic diversity as the entire global sample, suggesting the current epidemic can be traced back to the outbreak of a single clonal lineage. These data are consistent with the current chytridiomycosis epidemic resulting from a novel pathogen undergoing a rapid and recent range expansion. The widespread occurrence of the same lineage in both healthy and declining populations suggests that the outcome of the disease is contingent on environmental factors and host resistance. PMID:19478871

  7. Population growth and the decline of natural Southern yellow pine forests

    Treesearch

    David B. South; Edward R. Buckner

    2004-01-01

    Population growth has created social and economic pressures that affect the sustainability of naturally regenerated southern yellow pine forests. Major causes of this decline include (1) a shift in public attitudes regarding woods burning (from one favoring it to one that favors fire suppression) and (2) an increase in land values (especially near urban centers). The...

  8. Monarch butterfly population decline in North America: identifying the threatening processes.

    PubMed

    Thogmartin, Wayne E; Wiederholt, Ruscena; Oberhauser, Karen; Drum, Ryan G; Diffendorfer, Jay E; Altizer, Sonia; Taylor, Orley R; Pleasants, John; Semmens, Darius; Semmens, Brice; Erickson, Richard; Libby, Kaitlin; Lopez-Hoffman, Laura

    2017-09-01

    The monarch butterfly (Danaus plexippus) population in North America has sharply declined over the last two decades. Despite rising concern over the monarch butterfly's status, no comprehensive study of the factors driving this decline has been conducted. Using partial least-squares regressions and time-series analysis, we investigated climatic and habitat-related factors influencing monarch population size from 1993 to 2014. Potential threats included climatic factors, habitat loss (milkweed and overwinter forest), disease and agricultural insecticide use (neonicotinoids). While climatic factors, principally breeding season temperature, were important determinants of annual variation in abundance, our results indicated strong negative relationships between population size and habitat loss variables, principally glyphosate use, but also weaker negative effects from the loss of overwinter forest and breeding season use of neonicotinoids. Further declines in population size because of glyphosate application are not expected. Thus, if remaining threats to habitat are mitigated we expect climate-induced stochastic variation of the eastern migratory population of monarch butterfly around a relatively stationary population size.

  9. Monarch butterfly population decline in North America: identifying the threatening processes

    USGS Publications Warehouse

    Thogmartin, Wayne E.; Wiederholt, Ruscena; Oberhauser, Karen; Drum, Ryan G.; Diffendorfer, Jay E.; Altizer, Sonia; Taylor, Orley R.; Pleasants, John M.; Semmens, Darius J.; Semmens, Brice X.; Erickson, Richard A.; Libby, Kaitlin; Lopez-Hoffman, Laura

    2017-01-01

    The monarch butterfly (Danaus plexippus) population in North America has sharply declined over the last two decades. Despite rising concern over the monarch butterfly's status, no comprehensive study of the factors driving this decline has been conducted. Using partial least-squares regressions and time-series analysis, we investigated climatic and habitat-related factors influencing monarch population size from 1993 to 2014. Potential threats included climatic factors, habitat loss (milkweed and overwinter forest), disease and agricultural insecticide use (neonicotinoids). While climatic factors, principally breeding season temperature, were important determinants of annual variation in abundance, our results indicated strong negative relationships between population size and habitat loss variables, principally glyphosate use, but also weaker negative effects from the loss of overwinter forest and breeding season use of neonicotinoids. Further declines in population size because of glyphosate application are not expected. Thus, if remaining threats to habitat are mitigated we expect climate-induced stochastic variation of the eastern migratory population of monarch butterfly around a relatively stationary population size.

  10. Pesticides are involved with population declines of amphibians in the California Sierra Nevadas

    USGS Publications Warehouse

    Sparling, D.W.; Fellers, G.; McConnell, L.

    2001-01-01

    Several species of frogs and toads are in serious decline in the Sierra Nevada Mountains of California. These species include the threatened red-legged frog ( Rana aurora ), foothill yellow-legged frog ( R. boylii ), mountain yellow-legged frog ( R. muscosa ), Cascades frog ( Rana cascadae ), western toad ( Bufo boreas ) and Yosemite toad ( B. canorus ). For many of these species current distributions are down to 10% of historical ranges. Several factors including introduced predators, habitat loss, and ultraviolet radiation have been suggested as causes of these declines. Another probable cause is air-borne pesticides from the Central Valley of California. The Central Valley, especially the San Joaquin Valley, is a major agricultural region where millions of pounds of active ingredient pesticides are applied each year (http://www.cdpr.ca.gov/dprdatabase.htm). Prevailing westerly winds from the Pacific Coast transport these pesticides into the into the Sierras.

  11. Pesticides are involved with population declines of amphibians in the California Sierra Nevadas.

    PubMed

    Sparling, D W; Fellers, G; McConnell, L

    2001-05-01

    Several species of frogs and toads are in serious decline in the Sierra Nevada Mountains of California. These species include the threatened red-legged frog ( Rana aurora ), foothill yellow-legged frog ( R. boylii ), mountain yellow-legged frog ( R. muscosa ), Cascades frog ( Rana cascadae ), western toad ( Bufo boreas ) and Yosemite toad ( B. canorus ). For many of these species current distributions are down to 10% of historical ranges. Several factors including introduced predators, habitat loss, and ultraviolet radiation have been suggested as causes of these declines. Another probable cause is air-borne pesticides from the Central Valley of California. The Central Valley, especially the San Joaquin Valley, is a major agricultural region where millions of pounds of active ingredient pesticides are applied each year (http://www.cdpr.ca.gov/dprdatabase.htm). Prevailing westerly winds from the Pacific Coast transport these pesticides into the into the Sierras.

  12. Decline in an Atlantic Puffin Population: Evaluation of Magnitude and Mechanisms

    PubMed Central

    Miles, Will T. S.; Mavor, Roddy; Riddiford, Nick J.; Harvey, Paul V.; Riddington, Roger; Shaw, Deryk N.; Parnaby, David; Reid, Jane M.

    2015-01-01

    Determining which demographic and ecological parameters contribute to variation in population growth rate is crucial to understanding the dynamics of declining populations. This study aimed to evaluate the magnitude and mechanisms of an apparent major decline in an Atlantic Puffin Fratercula arctica population. This was achieved using a 27-year dataset to estimate changes in population size and in two key demographic rates: adult survival and breeding success. Estimated demographic variation was then related to two ecological factors hypothesised to be key drivers of demographic change, namely the abundance of the main predator at the study site, the Great Skua Stercorarius skua, and Atlantic Puffin chick food supply, over the same 27-year period. Using a population model, we assessed whether estimated variation in adult survival and reproductive success was sufficient to explain the population change observed. Estimates of Atlantic Puffin population size decreased considerably during the study period, approximately halving, whereas Great Skua population estimates increased, approximately trebling. Estimated adult Atlantic Puffin survival remained high across all years and did not vary with Great Skua abundance; however, Atlantic Puffin breeding success and quantities of fish prey brought ashore by adults both decreased substantially through the period. A population model combining best possible demographic parameter estimates predicted rapid population growth, at odds with the long-term decrease observed. To simulate the observed decrease, population models had to incorporate low immature survival, high immature emigration, or increasingly high adult non-breeding rates. We concluded that reduced recruitment of immatures into the breeding population was the most likely cause of population decrease. This study showed that increase in the size of a predator population does not always impact on the survival of adult prey and that reduced recruitment can be a crucial

  13. An evaluation of weather and disease as causes of decline in two populations of boreal toads

    USGS Publications Warehouse

    Scherer, R. D.; Muths, E.; Noon, B.R.; Corn, P.S.

    2005-01-01

    Two populations of boreal toads (Bufo boreas) experienced drastic declines in abundance in the late 1990s. Evidence supported the hypothesis of disease (the chytrid fungus, Batrachochytrium dendrobatidis) as the cause of these declines, but other hypotheses had not been evaluated. We used an 11-year capture-recapture data set to evaluate weather and disease as causes of these declines. We developed sets of mathematical models that reflected hypothesized relationships between several weather variables and annual survival rates of adult males in these populations. In addition, models that reflected the possibility that the declines were caused by an introduced fungus were developed. All models were fit to the data and were evaluated using a model selection criterion (QAICc). Our analysis provided strong support for the hypothesis of an introduced fungus and little support for the hypothesis that weather conditions caused the declines. Our results also suggest a strong, negative 'marking effect' on survival rates of boreal toads. Model-averaged estimates of survival rate are presented.

  14. [Factors Associated with Cognitive Decline in a Population Less than 65 Years Old. A Systematic Review].

    PubMed

    Aguirre-Acevedo, Daniel Camilo; Henao, Eliana; Tirado, Victoria; Muñoz, Claudia; Giraldo Arango, Diana; Lopera Restrepo, Francisco; Jaimes Barragán, Fabián

    2014-01-01

    Cognitive decline could begin 20 years before the diagnosis of dementia. Besides age, several factors related to medical, socioeconomic, and behavioral and genetic condition may be associated with cognitive decline. The aim of this systematic review was to summarize evidence on the risk and protective factors for cognitive decline in people under 65 years old. A systematic review was conducted using a search strategy in MEDLINE and Embase, including longitudinal studies to analyze the effect of protective or risk factors on cognitive decline in a population under 65 years old. A total of 22 studies were included in this review. Factors such as diabetes, hyperinsulinemia, overweight or obesity, metabolic syndrome, education, physical activity, cognitive stimulation, marital status and diet, could be related to cognitive decline before 65 years of age. Cardiovascular risk factors and lifestyle conditions may be associated with cognitive decline before 65 years of age. However, the quality of the evidence was low. Copyright © 2013 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

  15. Biological annihilation via the ongoing sixth mass extinction signaled by vertebrate population losses and declines

    PubMed Central

    Ceballos, Gerardo; Ehrlich, Paul R.; Dirzo, Rodolfo

    2017-01-01

    The population extinction pulse we describe here shows, from a quantitative viewpoint, that Earth’s sixth mass extinction is more severe than perceived when looking exclusively at species extinctions. Therefore, humanity needs to address anthropogenic population extirpation and decimation immediately. That conclusion is based on analyses of the numbers and degrees of range contraction (indicative of population shrinkage and/or population extinctions according to the International Union for Conservation of Nature) using a sample of 27,600 vertebrate species, and on a more detailed analysis documenting the population extinctions between 1900 and 2015 in 177 mammal species. We find that the rate of population loss in terrestrial vertebrates is extremely high—even in “species of low concern.” In our sample, comprising nearly half of known vertebrate species, 32% (8,851/27,600) are decreasing; that is, they have decreased in population size and range. In the 177 mammals for which we have detailed data, all have lost 30% or more of their geographic ranges and more than 40% of the species have experienced severe population declines (>80% range shrinkage). Our data indicate that beyond global species extinctions Earth is experiencing a huge episode of population declines and extirpations, which will have negative cascading consequences on ecosystem functioning and services vital to sustaining civilization. We describe this as a “biological annihilation” to highlight the current magnitude of Earth’s ongoing sixth major extinction event. PMID:28696295

  16. Hypercholesterolemia in elders is associated with slower cognitive decline: a prospective, population-based study (NEDICES).

    PubMed

    Benito-León, Julián; Vega-Quiroga, Saturio; Villarejo-Galende, Alberto; Bermejo-Pareja, Félix

    2015-03-15

    Studies investigating the association between hypercholesterolemia in the elderly and cognitive decline report discrepant outcomes. We determined in a prospective population-based cohort (NEDICES) in elders whether hypercholesterolemia was associated with slower cognitive decline. Participants were evaluated at baseline and 3 years later. Baseline demographic variables were recorded. Hypercholesterolemia was defined by total cholesterol of >200mg/dl or current use of lipid-lowering drugs. At baseline and at follow-up, a 37-item version of the Mini-Mental State Examination (37-MMSE) was administered. The final sample, 2015 participants (72.9 ± 6.1 years), comprised 1166 (57.9%) hypercholesterolemic and 849 (42.1%) non-hypercholesterolemic participants (reference category). The mean follow-up was 3.4 ± 0.5 years. During the three year follow-up period, the 37-MMSE declined by 0.7 ± 4.3 points (median=0 point) in non-hypercholesterolemic participants vs. 0.3 ± 3.9 points in hypercholesterolemic participants (median=0 points) (Mann-Whitney test, p=0.007). In analyses adjusted for baseline age and other potential confounders, this difference remained robust. We also assessed the cognitive decline per unit time (i.e., the rate of cognitive decline). The rate of cognitive decline was 0.2 ± 1.3 (median=0.0) points/year for non-hypercholesterolemic participants and 0.1 ± 1.2 (median=0.0) points/year for hypercholesterolemic participants (Mann-Whitney test, p=0.028). In this prospective population-based cohort study, cognitive test scores among hypercholesterolemic elders declined more slowly than observed in their non-hypercholesterolemic counterparts. Additional studies are needed to confirm these results. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Achieving population-level violence declines: implications of the international crime drop for prevention programming.

    PubMed

    Eisner, Manuel; Nivette, Amy; Murray, Aja Louise; Krisch, Maria

    2016-09-01

    The Sustainable Development Goals (SDGs) adopted by the United Nations for the period 2016-2030 aim to achieve a substantial reduction of interpersonal violence. An increasing body of evidence of what works, emerging from randomized controlled trials, can inform public health policy decisions. However, there is very limited evidence on the kinds of mechanisms that lead to sustained declines in interpersonal violence at the population level. We discuss the implications of what is known about recent major declines in violence to guide violence-reduction policies.

  18. Further evidence for historical decline of Antarctic sea ice prior to satellite survey era?

    NASA Astrophysics Data System (ADS)

    Gersonde, Rainer; Esper, Oliver; Lohmann, Gerrit; Knorr, Gregor

    2013-04-01

    The decline in Arctic summer sea ice which accelerated during the present century to reach a yet unequaled minimum extent in 2012 as monitored by the satellite-based sea ice survey since the late 1970s is thought to represent one of the most striking examples of current climate change related to the anthropogenic global warming. In contrast, Antarctic sea ice extent has remained nearly unchanged during the past 40 years, according to the satellite survey. The statistical analysis of microfossil (diatom) signals indicative of sea ice occurrence retrieved from a large set of surface samples covering the Pacific, Atlantic and the eastern Indian sectors of the Southern Ocean suggests that Antarctic winter sea ice extent was more extended than the sea ice field documented by satellite surveys. The surface samples generally integrate signals deposited over 100-200 years. Most substantial offsets between the sedimentary proxy and satellite derived data on sea ice extent were encountered on latitudinal transects across the Pacific sector. Independent support for a 20th century decline of Antarctic sea ice fields by up to 25% prior to satellite survey comes from the analysis of whaling positions [1, 2], ice core proxies [3] and combinations of observations with numerical modeling [4]. Proxy records from Holocene sediment cores allow for further extension of sea ice records beyond the short instrumental record. These records indicate that the more extended Antarctic winter sea ice derived from the surface sediment record is a common feature in the present interglacial (Holocene) period, except for the earliest Holocene when the sea ice field was even smaller than present. The proxy results are suitable for validation of reanalysis and numerical model data and will allow for a better understanding of Antarctic sea ice sensitivity in response to natural and anthropogenic processes. [1] de la Mare, W. K. 2009. Clim. Change 92,461-493; [2] Cotté, C., Guinet, C. 2007. Deep

  19. Polar bear population dynamics in the southern Beaufort Sea during a period of sea ice decline

    USGS Publications Warehouse

    Bromaghin, Jeffrey F.; McDonald, Trent L.; Stirling, Ian; Derocher, Andrew E.; Richardson, Evan S.; Regehr, Eric V.; Douglas, David C.; Durner, George M.; Atwood, Todd C.; Amstrup, Steven C.

    2015-01-01

    In the southern Beaufort Sea of the United States and Canada, prior investigations have linked declines in summer sea ice to reduced physical condition, growth, and survival of polar bears (Ursus maritimus). Combined with projections of population decline due to continued climate warming and the ensuing loss of sea ice habitat, those findings contributed to the 2008 decision to list the species as threatened under the U.S. Endangered Species Act. Here, we used mark–recapture models to investigate the population dynamics of polar bears in the southern Beaufort Sea from 2001 to 2010, years during which the spatial and temporal extent of summer sea ice generally declined. Low survival from 2004 through 2006 led to a 25–50% decline in abundance. We hypothesize that low survival during this period resulted from (1) unfavorable ice conditions that limited access to prey during multiple seasons; and possibly, (2) low prey abundance. For reasons that are not clear, survival of adults and cubs began to improve in 2007 and abundance was comparatively stable from 2008 to 2010, with ~900 bears in 2010 (90% CI 606–1212). However, survival of subadult bears declined throughout the entire period. Reduced spatial and temporal availability of sea ice is expected to increasingly force population dynamics of polar bears as the climate continues to warm. However, in the short term, our findings suggest that factors other than sea ice can influence survival. A refined understanding of the ecological mechanisms underlying polar bear population dynamics is necessary to improve projections of their future status and facilitate development of management strategies.

  20. Polar bear population dynamics in the southern Beaufort Sea during a period of sea ice decline.

    PubMed

    Bromaghin, Jeffrey F; Mcdonald, Trent L; Stirling, Ian; Derocher, Andrew E; Richardson, Evan S; Regehr, Eric V; Douglas, David C; Durner, George M; Atwood, Todd; Amstrup, Steven C

    2015-04-01

    In the southern Beaufort Sea of the United States and Canada, prior investigations have linked declines in summer sea ice to reduced physical condition, growth, and survival of polar bears (Ursus maritimus). Combined with projections of population decline due to continued climate warming and the ensuing loss of sea ice habitat, those findings contributed to the 2008 decision to list the species as threatened under the U.S. Endangered Species Act. Here, we used mark-recapture models to investigate the population dynamics of polar bears in the southern Beaufort Sea from 2001 to 2010, years during which the spatial and temporal extent of summer sea ice generally declined. Low survival from 2004 through 2006 led to a 25-50% decline in abundance. We hypothesize that low survival during this period resulted from (1) unfavorable ice conditions that limited access to prey during multiple seasons; and possibly, (2) low prey abundance. For reasons that are not clear, survival of adults and cubs began to improve in 2007 and abundance was comparatively stable from 2008 to 2010, with ~900 bears in 2010 (90% CI 606-1212). However, survival of subadult bears declined throughout the entire period. Reduced spatial and temporal availability of sea ice is expected to increasingly force population dynamics of polar bears as the climate continues to warm. However, in the short term, our findings suggest that factors other than sea ice can influence survival. A refined understanding of the ecological mechanisms underlying polar bear population dynamics is necessary to improve projections of their future status and facilitate development of management strategies.

  1. Chronic Lung Function Decline in Cotton Textile Workers: Roles of Historical and Recent Exposures to Endotoxin

    PubMed Central

    Shi, Jing; Mehta, Amar J.; Hang, Jing-qing; Zhang, Hongxi; Dai, Helian; Su, Li; Eisen, Ellen A.; Christiani, David C.

    2010-01-01

    Background Long-term occupational exposure to cotton dust that contains endotoxin is associated with chronic respiratory symptoms and excessive decline in forced expiratory volume in 1 sec (FEV1), but the mechanisms of endotoxin-related chronic airflow obstruction remain unclear. Objective In the current study, we examined temporal aspects of the exposure–response relationship between airborne endotoxin exposure, longitudinal change in FEV1, and respiratory symptoms in a cohort of Chinese cotton textile workers. Methods This prospective cohort study followed 447 cotton textile workers from 1981 to 2006.at approximately 5-year intervals. We used a generalized estimating equations approach to model FEV1 level and respiratory symptoms as a function of past exposure (cumulative exposure up to the start of the most recent 5-year survey interval) and cumulative exposure (within the most recent interval) to endotoxins, after adjusting for other covariates. Models were stratified by active versus retired work status and by years employed before the baseline survey (< 5 and ≥ 5 years). Results and conclusions Past exposure to endotoxin was associated with reduced FEV1 level among retired cotton workers. Among all cotton workers, past exposure was more strongly associated with reduced FEV1 for those hired < 5 years before baseline than for those who were hired ≥ 5 years after baseline. Recent endotoxin exposure was significantly associated with byssinosis, chronic bronchitis, and chronic cough. PMID:20797932

  2. Demographic stochasticity in small remnant populations of the declining distylous plant Primula veris

    USGS Publications Warehouse

    Kery, M.; Matthies, D.; Schmid, B.

    2003-01-01

    We studied ecological consequences of distyly for the declining perennial plant Primula veris in the Swiss Jura. Distyly favours cross-fertilization and avoids inbreeding, but may lead to pollen limitation and reduced reproduction if morph frequencies deviate from 50 %. Disassortative mating is promoted by the reciprocal position of stigmas and anthers in the two morphs (pin and thrum) and by intramorph incompatibility and should result in equal frequencies of morphs at equilibrium. However, deviations could arise because of demographic stochasticity, the lower intra-morph incompatibility of the pin morph, and niche differentiation between morphs. Demographic stochasticity should result in symmetric deviations from an even morph frequency among populations and in increased deviations with decreasing population size. If crosses between pins occurred, these would only generate pins, and this could result in a pin-bias of morph frequencies in general and in small populations in particular. If the morphs have different niches, morph frequencies should be related to environmental factors, morphs might be spatially segregated, and morphological differences between morphs would be expected. We tested these hypotheses in the declining distylous P. veris. We studied morph frequencies in relation to environmental conditions and population size, spatial segregation in field populations, morphological differences between morphs, and growth responses to nutrient addition. Morph frequencies in 76 populations with 1 - 80000 flowering plants fluctuated symmetrically about 50 %. Deviations from 50 % were much larger in small populations, and sixof the smallest populations had lost one morph altogether. In contrast, morph frequencies were neither related to population size nor to 17 measures of environmental conditions. We found no spatial segregation or morphological differences in the field or in the common garden. The results suggest that demographic stochasticity caused

  3. Emerging Infectious Disease Leads to Rapid Population Declines of Common British Birds

    PubMed Central

    Toms, Mike P.; Peck, Kirsi M.; Kirkwood, James K.; Chantrey, Julian; Clatworthy, Innes R.; Evans, Andy D.; Hughes, Laura A.; Hutchinson, Oliver C.; John, Shinto K.; Pennycott, Tom W.; Perkins, Matthew W.; Rowley, Peter S.; Simpson, Vic R.; Tyler, Kevin M.; Cunningham, Andrew A.

    2010-01-01

    Emerging infectious diseases are increasingly cited as threats to wildlife, livestock and humans alike. They can threaten geographically isolated or critically endangered wildlife populations; however, relatively few studies have clearly demonstrated the extent to which emerging diseases can impact populations of common wildlife species. Here, we report the impact of an emerging protozoal disease on British populations of greenfinch Carduelis chloris and chaffinch Fringilla coelebs, two of the most common birds in Britain. Morphological and molecular analyses showed this to be due to Trichomonas gallinae. Trichomonosis emerged as a novel fatal disease of finches in Britain in 2005 and rapidly became epidemic within greenfinch, and to a lesser extent chaffinch, populations in 2006. By 2007, breeding populations of greenfinches and chaffinches in the geographic region of highest disease incidence had decreased by 35% and 21% respectively, representing mortality in excess of half a million birds. In contrast, declines were less pronounced or absent in these species in regions where the disease was found in intermediate or low incidence. Also, populations of dunnock Prunella modularis, which similarly feeds in gardens, but in which T. gallinae was rarely recorded, did not decline. This is the first trichomonosis epidemic reported in the scientific literature to negatively impact populations of free-ranging non-columbiform species, and such levels of mortality and decline due to an emerging infectious disease are unprecedented in British wild bird populations. This disease emergence event demonstrates the potential for a protozoan parasite to jump avian host taxonomic groups with dramatic effect over a short time period. PMID:20805869

  4. Survival and population size of a resident bird species are declining as temperature increases.

    PubMed

    Santisteban, Leonard; Benkman, Craig W; Fetz, Trevor; Smith, Julie W

    2012-03-01

    1. A large number of migratory bird species appear to be declining as the result of climate change, but whether resident bird species have or will be adversely affected by climate change is less clear. We focus on the South Hills crossbill (Loxia curvirostra complex), which is endemic to about 70 km(2) of Rocky Mountain lodgepole pine (Pinus contorta latifolia) forest in southern Idaho, USA. 2. Our results indicate that the South Hills crossbill has declined by over 60% between 2003 and 2008, and that decreasing adult survival drives this population decline. 3. We evaluated the relative support for multiple hypotheses linking crossbill survival to climate, an ectoparasitic mite (scaly-leg mites Knemidokoptes jamaicensis), and the recent emergence of West Nile virus. Changes in adult apparent survival rate were closely associated with average spring and annual temperatures, and with high temperatures (≥32 °C) during summer, which have increased during the last decade. In contrast, there was little evidence that scaly-leg mites or West Nile virus contributed to recent declines in adult survival. 4. The most probable mechanism causing the decline in adult survival and population size is a decrease in the availability of their primary food resource, seeds in serotinous pine cones. Cone production has declined with increasing annual temperatures, and these cones appear to be prematurely opening owing to increasingly hot summer conditions releasing their seeds and reducing the carrying capacity for crossbills later in the year. 5. In light of regional climate change forecasts, which include an increase in both annual temperature and hot days (>32 °C), and the likely disappearance of lodgepole pine from southern Idaho by the end of this century, additional research is needed to determine how to maintain lodgepole pine forests and their supply of seeds to conserve one of the few bird species endemic to the continental United States.

  5. Large numbers of vertebrates began rapid population decline in the late 19th century

    PubMed Central

    Li, Haipeng; Xiang-Yu, Jinggong; Dai, Guangyi; Gu, Zhili; Ming, Chen; Yang, Zongfeng; Ryder, Oliver A.; Li, Wen-Hsiung; Fu, Yun-Xin; Zhang, Ya-Ping

    2016-01-01

    Accelerated losses of biodiversity are a hallmark of the current era. Large declines of population size have been widely observed and currently 22,176 species are threatened by extinction. The time at which a threatened species began rapid population decline (RPD) and the rate of RPD provide important clues about the driving forces of population decline and anticipated extinction time. However, these parameters remain unknown for the vast majority of threatened species. Here we analyzed the genetic diversity data of nuclear and mitochondrial loci of 2,764 vertebrate species and found that the mean genetic diversity is lower in threatened species than in related nonthreatened species. Our coalescence-based modeling suggests that in many threatened species the RPD began ∼123 y ago (a 95% confidence interval of 20–260 y). This estimated date coincides with widespread industrialization and a profound change in global living ecosystems over the past two centuries. On average the population size declined by ∼25% every 10 y in a threatened species, and the population size was reduced to ∼5% of its ancestral size. Moreover, the ancestral size of threatened species was, on average, ∼22% smaller than that of nonthreatened species. Because the time period of RPD is short, the cumulative effect of RPD on genetic diversity is still not strong, so that the smaller ancestral size of threatened species may be the major cause of their reduced genetic diversity; RPD explains 24.1–37.5% of the difference in genetic diversity between threatened and nonthreatened species. PMID:27872315

  6. Ancient and Contemporary DNA Reveal a Pre-Human Decline but No Population Bottleneck Associated with Recent Human Persecution in the Kea (Nestor notabilis)

    PubMed Central

    Dussex, Nicolas; Rawlence, Nicolas J.; Robertson, Bruce C.

    2015-01-01

    The impact of population bottlenecks is an important factor to consider when assessing species survival. Population declines can considerably limit the evolutionary potential of species and make them more susceptible to stochastic events. New Zealand has a well documented history of decline of endemic avifauna related to human colonization. Here, we investigate the genetic effects of a recent population decline in the endangered kea (Nestor notabilis). Kea have undergone a long-lasting persecution between the late 1800s to 1970s where an estimated 150,000 kea were culled under a governmental bounty scheme. Kea now number 1,000–5,000 individuals in the wild and it is likely that the recent population decline may have reduced the genetic diversity of the species. Comparison of contemporary (n = 410), historical (n = 15) and fossil samples (n = 4) showed a loss of mitochondrial diversity since the end of the last glaciation (Otiran Glacial) but no loss of overall genetic diversity associated with the cull. Microsatellite data indicated a recent bottleneck for only one population and a range-wide decline in Ne dating back some 300 – 6,000 years ago, a period predating European arrival in NZ. These results suggest that despite a recent human persecution, kea might have experienced a large population decline before stabilizing in numbers prior to human settlement of New Zealand in response to Holocene changes in habitat distribution. Our study therefore highlights the need to understand the respective effects of climate change and human activities on endangered species dynamics when proposing conservation guidelines. PMID:25719752

  7. Occupancy patterns of regionally declining grassland sparrow populations in a forested Pennsylvania landscape.

    PubMed

    Hill, Jason M; Diefenbach, Duane R

    2014-06-01

    Organisms can be affected by processes in the surrounding landscape outside the boundary of habitat areas and by local vegetation characteristics. There is substantial interest in understanding how these processes affect populations of grassland birds, which have experienced substantial population declines. Much of our knowledge regarding patterns of occupancy and density stem from prairie systems, whereas relatively little is known regarding how occurrence and abundance of grassland birds vary in reclaimed surface mine grasslands. Using distance sampling and single-season occupancy models, we investigated how the occupancy probability of Grasshopper (Ammodramus savannarum) and Henslow's Sparrows (A. henslowii) on 61 surface mine grasslands (1591 ha) in Pennsylvania changed from 2002 through 2011 in response to landscape, grassland, and local vegetation characteristics . A subset (n = 23; 784 ha) of those grasslands were surveyed in 2002, and we estimated changes in sparrow density and vegetation across 10 years. Grasshopper and Henslow's Sparrow populations declined 72% and 49%, respectively from 2002 to 2011, whereas overall woody vegetation density increased 2.6 fold. Henslow's Sparrows avoided grasslands with perimeter-area ratios ≥0.141 km/ha and woody shrub densities ≥0.04 shrubs/m(2). Both species occupied grasslands ≤13 ha, but occupancy probability declined with increasing grassland perimeter-area ratio and woody shrub density. Grassland size, proximity to nearest neighboring grassland (x = 0.2 km), and surrounding landscape composition at 0.5, 1.5, and 3.0 km were not parsimonious predictors of occupancy probability for either species. Our results suggest that reclaimed surface mine grasslands, without management intervention, are ephemeral habitats for Grasshopper and Henslow's Sparrows. Given the forecasted decline in surface coal production for Pennsylvania, it is likely that both species will continue to decline in our study region for the

  8. Occupancy patterns of regionally declining grassland sparrow populations in a forested Pennsylvania landscape

    USGS Publications Warehouse

    Hill, Jason M.; Diefenbach, Duane R.

    2014-01-01

    Organisms can be affected by processes in the surrounding landscape outside the boundary of habitat areas and by local vegetation characteristics. There is substantial interest in understanding how these processes affect populations of grassland birds, which have experienced substantial population declines. Much of our knowledge regarding patterns of occupancy and density stem from prairie systems, whereas relatively little is known regarding how occurrence and abundance of grassland birds vary in reclaimed surface mine grasslands. Using distance sampling and single-season occupancy models, we investigated how the occupancy probability of Grasshopper (Ammodramus savannarum) and Henslow's Sparrows (A. henslowii) on 61 surface mine grasslands (1591 ha) in Pennsylvania changed from 2002 through 2011 in response to landscape, grassland, and local vegetation characteristics . A subset (n = 23; 784 ha) of those grasslands were surveyed in 2002, and we estimated changes in sparrow density and vegetation across 10 years. Grasshopper and Henslow's Sparrow populations declined 72% and 49%, respectively from 2002 to 2011, whereas overall woody vegetation density increased 2.6 fold. Henslow's Sparrows avoided grasslands with perimeter–area ratios ≥0.141 km/ha and woody shrub densities ≥0.04 shrubs/m2. Both species occupied grasslands ≤13 ha, but occupancy probability declined with increasing grassland perimeter–area ratio and woody shrub density. Grassland size, proximity to nearest neighboring grassland ( = 0.2 km), and surrounding landscape composition at 0.5, 1.5, and 3.0 km were not parsimonious predictors of occupancy probability for either species. Our results suggest that reclaimed surface mine grasslands, without management intervention, are ephemeral habitats for Grasshopper and Henslow's Sparrows. Given the forecasted decline in surface coal production for Pennsylvania, it is likely that both species will continue to decline in our study region for the

  9. Attributing mortality among drivers of population decline in Acropora palmata in the Florida Keys (USA)

    NASA Astrophysics Data System (ADS)

    Williams, D. E.; Miller, M. W.

    2012-06-01

    Acropora palmata populations have experienced steep declines over the past 30 years. Although numerous culprits are recognized, their relative contributions to the decline are poorly quantified, making it difficult to prioritize effective conservation measures. In 2004, a demographic monitoring program was implemented in the Florida Keys (USA), aimed at determining the relative importance of various stressors affecting A. palmata. A subset of randomly selected A. palmata colonies within 15 fore-reef plots was tagged and surveyed three to four times per year over 7 years. Colony size, live tissue, prevalence of disease, snail ( Coralliophila abbreviata) predation, physical damage and other conditions were assessed at each survey. The estimated effect of each condition causing recent mortality was ranked, and together, these parameters were used to attribute the population-level tissue loss associated with each condition. In addition, all new colonies in the study plots were counted and assessed annually in order to track trends in total colony count and live tissue abundance. Between 2004 and 2010, the study population has shown more than 50% decline in live area from three main conditions: fragmentation, disease and snail predation. Approximately half of this decline occurred during the catastrophic 2005 hurricane season from which recovery has been minimal. Meanwhile, colony abundance has shown gradual decline throughout the study. Snail predation was the most prevalent condition. However, it ranked third in attributed tissue loss, behind breakage that occurred during the 2005 hurricane season, and disease. Thermal bleaching of A. palmata was not observed during this study. Because mortality continues to outpace recruitment and growth, intervention to ameliorate losses to the more manageable threats including predation and breakage could result in substantial conservation of live tissue, buying time for the abatement of less tractable threats to A. palmata

  10. Diclofenac residues as the cause of vulture population decline in Pakistan.

    PubMed

    Oaks, J Lindsay; Gilbert, Martin; Virani, Munir Z; Watson, Richard T; Meteyer, Carol U; Rideout, Bruce A; Shivaprasad, H L; Ahmed, Shakeel; Chaudhry, Muhammad Jamshed Iqbal; Arshad, Muhammad; Mahmood, Shahid; Ali, Ahmad; Khan, Aleem Ahmed

    2004-02-12

    The Oriental white-backed vulture (OWBV; Gyps bengalensis) was once one of the most common raptors in the Indian subcontinent. A population decline of >95%, starting in the 1990s, was first noted at Keoladeo National Park, India. Since then, catastrophic declines, also involving Gyps indicus and Gyps tenuirostris, have continued to be reported across the subcontinent. Consequently these vultures are now listed as critically endangered by BirdLife International. In 2000, the Peregrine Fund initiated its Asian Vulture Crisis Project with the Ornithological Society of Pakistan, establishing study sites at 16 OWBV colonies in the Kasur, Khanewal and Muzaffargarh-Layyah Districts of Pakistan to measure mortality at over 2,400 active nest sites. Between 2000 and 2003, high annual adult and subadult mortality (5-86%) and resulting population declines (34-95%) (ref. 5 and M.G., manuscript in preparation) were associated with renal failure and visceral gout. Here, we provide results that directly correlate residues of the anti-inflammatory drug diclofenac with renal failure. Diclofenac residues and renal disease were reproduced experimentally in OWBVs by direct oral exposure and through feeding vultures diclofenac-treated livestock. We propose that residues of veterinary diclofenac are responsible for the OWBV decline.

  11. Diclofenac residues as the cause of vulture population decline in Pakistan

    USGS Publications Warehouse

    Oaks, J.L.; Gilbert, M.; Virani, M.Z.; Watson, R.T.; Meteyer, C.U.; Rideout, B.A.; Shivaprasad, H.L.; Ahmed, S.; Chaudhry, M.J.I.; Arshad, M.; Mahmood, S.; Ali, A.; Khan, A.A.

    2004-01-01

    The Oriental white-backed vulture (OWBV; Gyps bengalensis) was once one of the most common raptors in the Indian subcontinent. A population decline of >95%, starting in the 1990s, was first noted at Keoladeo National Park, India. Since then, catastrophic declines, also involving Gyps indicus and Gyps tenuirostris, have continued to be reported across the subcontinent. Consequently these vultures are now listed as critically endangered by BirdLife International. In 2000, the Peregrine Fund initiated its Asian Vulture Crisis Project with the Ornithological Society of Pakistan, establishing study sites at 16 OWBV colonies in the Kasur, Khanewal and Muzaffargarha??Layyah Districts of Pakistan to measure mortality at over 2,400 active nest sites5. Between 2000 and 2003, high annual adult and subadult mortality (5a??86%) and resulting population declines (34a??95%) (ref. 5 and M.G., manuscript in preparation) were associated with renal failure and visceral gout. Here, we provide results that directly correlate residues of the anti-inflammatory drug diclofenac with renal failure. Diclofenac residues and renal disease were reproduced experimentally in OWBVs by direct oral exposure and through feeding vultures diclofenac-treated livestock. We propose that residues of veterinary diclofenac are responsible for the OWBV decline.

  12. Is it possible to receive information about the historical geomagnetic declination from church orientations?

    NASA Astrophysics Data System (ADS)

    Draxler, Andrea; Rauch, Roman; Gruber, Karin; Leohardt, Roman

    2013-04-01

    It is widely known that the main structure of many churches was planned and built in an east-ward direction. This procedure, called "easting", was used for centuries especially in catholic structures. "Easting" usually refers to the direction of sunrise at the church patron's day. Assuming however that this direction is estimated by compasses there could be a significant correlation between the geographic orientation of the churches and the value of magnetic declination at the date of building. In Europe compasses are known since the 11th century. For this study altogether 124 churches located in lower Austria and built between 1100 to 1900 were analysed. Of primary interest is the geographic orientation of the churches, which was extracted out of georeferenced satellite images in Google Earth and the NO Atlas. The measured orientation of the church's nave is then compared to the geographic east direction as well as to the magnetic east direction, according to the magnetic field in the church's construction year which is determined by published geomagnetic field models. The resulting deviations for the geographic east direction split our data into two groups: churches that were built before 1500 and churches that were constructed after 1500. The boundary between these two data sets is marked by the Ottoman wars in the 16th century, where a lot of churches were destroyed. After 1500 the differences between the church's orientation and the geographic east direction are significantly bigger than before the Ottoman wars, so we shifted our focus for the following calculations on the time span from 1100 to 1500, where we found quite small deviations for both the geographic and the magnetic east direction. The principle idea of church orientation, usually referred to as "Easting" is to direct the church to the point of sunrise on the patron saint's day. Therefore we also calculated the solar azimuth on the patron saint's day and compared it to the orientation of the

  13. Population-specific demographic estimates provide insights into declines of Lark Buntings (Calamospiza melanocorys)

    USGS Publications Warehouse

    Yackel Adams, A.A.; Skagen, S.K.; Savidge, J.A.

    2007-01-01

    Many North American prairie bird populations have recently declined, and the causes of these declines remain largely unknown. To determine whether population limitation occurs during breeding, we evaluated the stability of a population of prairie birds using population-specific values for fecundity and postfledging survival. During 2001-2003, we radiomarked 67 female Lark Buntings (Calamospiza melanocorys) to determine annual fecundity and evaluate contributing factors such as nest survival and breeding response (number of breeding attempts and dispersal). Collectively, 67 females built 112 nests (1.67 ?? 0.07 nests female-1 season-1; range: 1-3); 34 were second nests and 11 were third nests. Daily nest survival estimates were similar for initial and later nests with overall nest survival (DSR 19) of 30.7% and 31.7%, respectively. Nest predation was the most common cause of failure (92%). Capture and radiomarking of females did not affect nest survival. Lark Bunting dispersal probabilities increased among females that fledged young from initial nests and females that lost their original nests late in the season. Conservative and liberal estimates of mean annual fecundity were 0.96 ?? 0.11 and 1.24 ?? 0.09 female offspring per female, respectively. Given the fecundity and juvenile-survival estimates for this population, annual adult survival values of 71-77% are necessary to achieve a stable population. Because adult survival of prairie passerines ranges between 55% and 65%, this study area may not be capable of sustaining a stable population in the absence of immigration. We contrast our population assessment with one that assumes indirect values of fecundity and juvenile survival. To elucidate limiting factors, estimation of population-specific demographic parameters is desirable. We present an approach for selecting species and areas for evaluation of population stability. ?? The American Ornithologists' Union, 2007.

  14. Declines in low-elevation subalpine tree populations outpace growth in high-elevation populations with warming

    DOE PAGES

    Conlisk, Erin; Castanha, Cristina; Germino, Matthew J.; ...

    2017-02-08

    Species distribution shifts in response to climate change require that recruitment increase beyond current range boundaries. For trees with long life spans, the importance of climate-sensitive seedling establishment to the pace of range shifts has not been demonstrated quantitatively. Using spatially explicit, stochastic population models combined with data from long-term forest surveys, we explored whether the climate-sensitivity of recruitment observed in climate manipulation experiments was sufficient to alter populations and elevation ranges of two widely distributed, high-elevation North American conifers. Empirically observed, warming-driven declines in recruitment led to rapid modelled population declines at the low-elevation, ‘warm edge’ of subalpine forestmore » and slow emergence of populations beyond the high-elevation, ‘cool edge’. Because population declines in the forest occurred much faster than population emergence in the alpine, we observed range contraction for both species. For Engelmann spruce, this contraction was permanent over the modelled time horizon, even in the presence of increased moisture. For limber pine, lower sensitivity to warming may facilitate persistence at low elevations – especially in the presence of increased moisture – and rapid establishment above tree line, and, ultimately, expansion into the alpine. Synthesis. Assuming 21st century warming and no additional moisture, population dynamics in high-elevation forests led to transient range contractions for limber pine and potentially permanent range contractions for Engelmann spruce. Thus, limitations to seedling recruitment with warming can constrain the pace of subalpine tree range shifts.« less

  15. Role of egg predation by haddock in the decline of an Atlantic herring population.

    PubMed

    Richardson, David E; Hare, Jonathan A; Fogarty, Michael J; Link, Jason S

    2011-08-16

    Theoretical studies suggest that the abrupt and substantial changes in the productivity of some fisheries species may be explained by predation-driven alternate stable states in their population levels. With this hypothesis, an increase in fishing or a natural perturbation can drive a population from an upper to a lower stable-equilibrium population level. After fishing is reduced or the perturbation ended, this low population level can persist due to the regulatory effect of the predator. Although established in theoretical studies, there is limited empirical support for predation-driven alternate stable states in exploited marine fish populations. We present evidence that egg predation by haddock (Melanogrammus aeglefinus) can cause alternate stable population levels in Georges Bank Atlantic herring (Clupea harengus). Egg predation by haddock explains a substantial decoupling of herring spawning stock biomass (an index of egg production) from observed larval herring abundance (an index of egg hatching). Estimated egg survival rates ranged from <2-70% from 1971 to 2005. A population model incorporating egg predation and herring fishing explains the major population trends of Georges Bank herring over four decades and predicts that, when the haddock population is high, seemingly conservative levels of fishing can still precipitate a severe decline in the herring population. These findings illustrate how efforts to rebuild fisheries can be undermined by not incorporating ecological interactions into fisheries models and management plans.

  16. Role of egg predation by haddock in the decline of an Atlantic herring population

    PubMed Central

    Richardson, David E.; Hare, Jonathan A.; Fogarty, Michael J.; Link, Jason S.

    2011-01-01

    Theoretical studies suggest that the abrupt and substantial changes in the productivity of some fisheries species may be explained by predation-driven alternate stable states in their population levels. With this hypothesis, an increase in fishing or a natural perturbation can drive a population from an upper to a lower stable-equilibrium population level. After fishing is reduced or the perturbation ended, this low population level can persist due to the regulatory effect of the predator. Although established in theoretical studies, there is limited empirical support for predation-driven alternate stable states in exploited marine fish populations. We present evidence that egg predation by haddock (Melanogrammus aeglefinus) can cause alternate stable population levels in Georges Bank Atlantic herring (Clupea harengus). Egg predation by haddock explains a substantial decoupling of herring spawning stock biomass (an index of egg production) from observed larval herring abundance (an index of egg hatching). Estimated egg survival rates ranged from <2–70% from 1971 to 2005. A population model incorporating egg predation and herring fishing explains the major population trends of Georges Bank herring over four decades and predicts that, when the haddock population is high, seemingly conservative levels of fishing can still precipitate a severe decline in the herring population. These findings illustrate how efforts to rebuild fisheries can be undermined by not incorporating ecological interactions into fisheries models and management plans. PMID:21825166

  17. Association of coloration mode with population declines and endangerment in Australian frogs.

    PubMed

    Forsman, Anders; Hagman, Mattias

    2009-12-01

    Successful protection of biodiversity requires increased understanding of the ecological characteristics that predispose some species to endangerment. Theory posits that species with polymorphic or variable coloration should have larger distributions, use more diverse resources, and be less vulnerable to population declines and extinctions, compared with taxa that do not vary in color. We used information from literature on 194 species of Australian frogs to search for associations of coloration mode with ecological variables. In general, species with variable or polymorphic color patterns had larger ranges, used more habitats, were less prone to have a negative population trend, and were estimated as less vulnerable to extinction compared with nonvariable species. An association of variable coloration with lower endangerment was also evident when we controlled statistically for the effects of range size. Nonvariable coloration was not a strong predictor of endangerment, and information on several characteristics is needed to reliably identify and protect species that are prone to decline and may become threatened by extinction in the near future. Analyses based on phylogenetic-independent contrasts did not support the hypothesis that evolutionary transitions between nonvariable and variable or polymorphic coloration have been accompanied by changes in the ecological variables we examined. Irrefutable demonstration of a role of color pattern variation in amphibian decline and in the dynamics and persistence of populations in general will require a manipulative experimental approach.

  18. Changes in landscape composition influence the decline of a threatened woodland caribou population.

    PubMed

    Wittmer, Heiko U; McLellan, Bruce N; Serrouya, Robert; Apps, Clayton D

    2007-05-01

    1. Large-scale habitat loss is frequently identified with loss of biodiversity, but examples of the direct effect of habitat alterations on changes in vital rates remain rare. Quantifying and understanding the relationship between habitat composition and changes in vital rates, however, is essential for the development of effective conservation strategies. 2. It has been suggested that the decline of woodland caribou Rangifer tarandus caribou populations in North America is precipitated by timber harvesting that creates landscapes of early seral forests. Such habitat changes have altered the predator-prey system resulting in asymmetric predation, where predators are maintained by alternative prey (i.e. apparent competition). However, a direct link between habitat condition and caribou population declines has not been documented. 3. We estimated survival probabilities for the threatened arboreal lichen-feeding ecotype of woodland caribou in British Columbia, Canada, at two different spatial scales. At the broader scale, observed variation in adult female survival rates among 10 distinct populations (range = 0.67-0.93) was best explained by variation in the amount of early seral stands within population ranges and population density. At the finer scale, home ranges of caribou killed by predators had lower proportions of old forest and more mid-aged forest as compared with multi-annual home ranges where caribou were alive. 4. These results are consistent with predictions from the apparent competition hypothesis and quantify direct fitness consequences for caribou following habitat alterations. We conclude that apparent competition can cause rapid population declines and even extinction where changes in species composition occur following large scale habitat change.

  19. Blood Pressure, Proteinuria, and Renal Function Decline: Associations in a Large Community-Based Population.

    PubMed

    Hirayama, Atsushi; Konta, Tsuneo; Kamei, Keita; Suzuki, Kazuko; Ichikawa, Kazunobu; Fujimoto, Shouichi; Iseki, Kunitoshi; Moriyama, Toshiki; Yamagata, Kunihiro; Tsuruya, Kazuhiko; Kimura, Kenjiro; Narita, Ichiei; Kondo, Masahide; Asahi, Koichi; Kurahashi, Issei; Ohashi, Yasuo; Watanabe, Tsuyoshi

    2015-09-01

    Hypertension and proteinuria are risk factors for adverse renal outcomes in patients with chronic kidney disease. This study investigated the associations of blood pressure and proteinuria on renal function in a community-based population. We analyzed data from a nationwide database of 141,514 subjects who participated in the annual "Specific Health Check and Guidance in Japan" checkup in 2008 and 2010. The study subjects were aged between 29 and 74 years, and the cohort comprised 40% men. We examined relationships between blood pressure levels, proteinuria at baseline, and the 2-year change in the estimated glomerular filtration rate (eGFR), which was determined using the Japanese equation. After adjusting for possible confounders, the change in the eGFR was inversely correlated with systolic blood pressure (SBP), but not diastolic blood pressure (DBP), at baseline, irrespective of the presence of proteinuria. Compared with the lowest SBP sixtile (≤118mm Hg), eGFRs declined significantly at SBPs ≥ 134mm Hg in subjects with proteinuria, while eGFRs declined significantly at SBPs ≥ 141mm Hg in those without proteinuria. At the same SBPs, renal function decline was faster and the risk for incident renal insufficiency was higher in subjects with proteinuria compared with those without proteinuria. This study showed that a difference in SBP, but not DBP, is independently associated with a rapid eGFR decline in the general Japanese population, and that the association of SBP on the decline of renal function was greater in subjects with proteinuria compared with those without proteinuria. © American Journal of Hypertension, Ltd 2015. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Mixed Fortunes: Ancient Expansion and Recent Decline in Population Size of a Subtropical Montane Primate, the Arunachal Macaque Macaca munzala

    PubMed Central

    Chakraborty, Debapriyo; Sinha, Anindya; Ramakrishnan, Uma

    2014-01-01

    Quaternary glacial oscillations are known to have caused population size fluctuations in many temperate species. Species from subtropical and tropical regions are, however, considerably less studied, despite representing most of the biodiversity hotspots in the world including many highly threatened by anthropogenic activities such as hunting. These regions, consequently, pose a significant knowledge gap in terms of how their fauna have typically responded to past climatic changes. We studied an endangered primate, the Arunachal macaque Macaca munzala, from the subtropical southern edge of the Tibetan plateau, a part of the Eastern Himalaya biodiversity hotspot, also known to be highly threatened due to rampant hunting. We employed a 534 bp-long mitochondrial DNA sequence and 22 autosomal microsatellite loci to investigate the factors that have potentially shaped the demographic history of the species. Analysing the genetic data with traditional statistical methods and advance Bayesian inferential approaches, we demonstrate a limited effect of past glacial fluctuations on the demographic history of the species before the last glacial maximum, approximately 20,000 years ago. This was, however, immediately followed by a significant population expansion possibly due to warmer climatic conditions, approximately 15,000 years ago. These changes may thus represent an apparent balance between that displayed by the relatively climatically stable tropics and those of the more severe, temperate environments of the past. This study also draws attention to the possibility that a cold-tolerant species like the Arunachal macaque, which could withstand historical climate fluctuations and grow once the climate became conducive, may actually be extremely vulnerable to anthropogenic exploitation, as is perhaps indicated by its Holocene ca. 30-fold population decline, approximately 3,500 years ago. Our study thus provides a quantitative appraisal of these demographically important

  1. Mixed fortunes: ancient expansion and recent decline in population size of a subtropical montane primate, the Arunachal macaque Macaca munzala.

    PubMed

    Chakraborty, Debapriyo; Sinha, Anindya; Ramakrishnan, Uma

    2014-01-01

    Quaternary glacial oscillations are known to have caused population size fluctuations in many temperate species. Species from subtropical and tropical regions are, however, considerably less studied, despite representing most of the biodiversity hotspots in the world including many highly threatened by anthropogenic activities such as hunting. These regions, consequently, pose a significant knowledge gap in terms of how their fauna have typically responded to past climatic changes. We studied an endangered primate, the Arunachal macaque Macaca munzala, from the subtropical southern edge of the Tibetan plateau, a part of the Eastern Himalaya biodiversity hotspot, also known to be highly threatened due to rampant hunting. We employed a 534 bp-long mitochondrial DNA sequence and 22 autosomal microsatellite loci to investigate the factors that have potentially shaped the demographic history of the species. Analysing the genetic data with traditional statistical methods and advance Bayesian inferential approaches, we demonstrate a limited effect of past glacial fluctuations on the demographic history of the species before the last glacial maximum, approximately 20,000 years ago. This was, however, immediately followed by a significant population expansion possibly due to warmer climatic conditions, approximately 15,000 years ago. These changes may thus represent an apparent balance between that displayed by the relatively climatically stable tropics and those of the more severe, temperate environments of the past. This study also draws attention to the possibility that a cold-tolerant species like the Arunachal macaque, which could withstand historical climate fluctuations and grow once the climate became conducive, may actually be extremely vulnerable to anthropogenic exploitation, as is perhaps indicated by its Holocene ca. 30-fold population decline, approximately 3,500 years ago. Our study thus provides a quantitative appraisal of these demographically important

  2. Demographic models and IPCC climate projections predict the decline of an emperor penguin population

    PubMed Central

    Jenouvrier, Stéphanie; Caswell, Hal; Barbraud, Christophe; Holland, Marika; Strœve, Julienne; Weimerskirch, Henri

    2009-01-01

    Studies have reported important effects of recent climate change on Antarctic species, but there has been to our knowledge no attempt to explicitly link those results to forecasted population responses to climate change. Antarctic sea ice extent (SIE) is projected to shrink as concentrations of atmospheric greenhouse gases (GHGs) increase, and emperor penguins (Aptenodytes forsteri) are extremely sensitive to these changes because they use sea ice as a breeding, foraging and molting habitat. We project emperor penguin population responses to future sea ice changes, using a stochastic population model that combines a unique long-term demographic dataset (1962–2005) from a colony in Terre Adélie, Antarctica and projections of SIE from General Circulation Models (GCM) of Earth's climate included in the most recent Intergovernmental Panel on Climate Change (IPCC) assessment report. We show that the increased frequency of warm events associated with projected decreases in SIE will reduce the population viability. The probability of quasi-extinction (a decline of 95% or more) is at least 36% by 2100. The median population size is projected to decline from ≈6,000 to ≈400 breeding pairs over this period. To avoid extinction, emperor penguins will have to adapt, migrate or change the timing of their growth stages. However, given the future projected increases in GHGs and its effect on Antarctic climate, evolution or migration seem unlikely for such long lived species at the remote southern end of the Earth. PMID:19171908

  3. Estimating freshwater turtle mortality rates and population declines following hook ingestion.

    PubMed

    Steen, David A; Robinson, Orin J

    2017-03-15

    Freshwater turtle populations are susceptible to declines following small increases in the mortality of adults, making it essential to identify and understand potential threats. Freshwater turtles ingest fish hooks associated with recreational angling, and this is likely a problem because hook ingestion is a source of additive mortality for sea turtles. We used a Bayesian-modeling framework, observed rates of hook ingestion by freshwater turtles, and mortality of sea turtles from hook ingestion to examine the probability that a freshwater turtle in a given population ingests a hook and subsequently dies from it. We used the results of these analyses and previously published life-history data to simulate the effects of hook ingestion on population growth for 3 species of freshwater turtle. In our simulation, the probability that an individual turtle ingests a hook and dies as a result was 1.2-11%. Our simulation results suggest that this rate of mortality from hook ingestion is sufficient to cause population declines. We believe we have identified fish-hook ingestion as a serious yet generally overlooked threat to the viability of freshwater turtle populations. © 2017 Society for Conservation Biology.

  4. Global climate change, war, and population decline in recent human history.

    PubMed

    Zhang, David D; Brecke, Peter; Lee, Harry F; He, Yuan-Qing; Zhang, Jane

    2007-12-04

    Although scientists have warned of possible social perils resulting from climate change, the impacts of long-term climate change on social unrest and population collapse have not been quantitatively investigated. In this study, high-resolution paleo-climatic data have been used to explore at a macroscale the effects of climate change on the outbreak of war and population decline in the preindustrial era. We show that long-term fluctuations of war frequency and population changes followed the cycles of temperature change. Further analyses show that cooling impeded agricultural production, which brought about a series of serious social problems, including price inflation, then successively war outbreak, famine, and population decline successively. The findings suggest that worldwide and synchronistic war-peace, population, and price cycles in recent centuries have been driven mainly by long-term climate change. The findings also imply that social mechanisms that might mitigate the impact of climate change were not significantly effective during the study period. Climate change may thus have played a more important role and imposed a wider ranging effect on human civilization than has so far been suggested. Findings of this research may lend an additional dimension to the classic concepts of Malthusianism and Darwinism.

  5. Global climate change, war, and population decline in recent human history

    PubMed Central

    Zhang, David D.; Brecke, Peter; Lee, Harry F.; He, Yuan-Qing; Zhang, Jane

    2007-01-01

    Although scientists have warned of possible social perils resulting from climate change, the impacts of long-term climate change on social unrest and population collapse have not been quantitatively investigated. In this study, high-resolution paleo-climatic data have been used to explore at a macroscale the effects of climate change on the outbreak of war and population decline in the preindustrial era. We show that long-term fluctuations of war frequency and population changes followed the cycles of temperature change. Further analyses show that cooling impeded agricultural production, which brought about a series of serious social problems, including price inflation, then successively war outbreak, famine, and population decline successively. The findings suggest that worldwide and synchronistic war–peace, population, and price cycles in recent centuries have been driven mainly by long-term climate change. The findings also imply that social mechanisms that might mitigate the impact of climate change were not significantly effective during the study period. Climate change may thus have played a more important role and imposed a wider ranging effect on human civilization than has so far been suggested. Findings of this research may lend an additional dimension to the classic concepts of Malthusianism and Darwinism. PMID:18048343

  6. Demographic models and IPCC climate projections predict the decline of an emperor penguin population.

    PubMed

    Jenouvrier, Stéphanie; Caswell, Hal; Barbraud, Christophe; Holland, Marika; Stroeve, Julienne; Weimerskirch, Henri

    2009-02-10

    Studies have reported important effects of recent climate change on Antarctic species, but there has been to our knowledge no attempt to explicitly link those results to forecasted population responses to climate change. Antarctic sea ice extent (SIE) is projected to shrink as concentrations of atmospheric greenhouse gases (GHGs) increase, and emperor penguins (Aptenodytes forsteri) are extremely sensitive to these changes because they use sea ice as a breeding, foraging and molting habitat. We project emperor penguin population responses to future sea ice changes, using a stochastic population model that combines a unique long-term demographic dataset (1962-2005) from a colony in Terre Adélie, Antarctica and projections of SIE from General Circulation Models (GCM) of Earth's climate included in the most recent Intergovernmental Panel on Climate Change (IPCC) assessment report. We show that the increased frequency of warm events associated with projected decreases in SIE will reduce the population viability. The probability of quasi-extinction (a decline of 95% or more) is at least 36% by 2100. The median population size is projected to decline from approximately 6,000 to approximately 400 breeding pairs over this period. To avoid extinction, emperor penguins will have to adapt, migrate or change the timing of their growth stages. However, given the future projected increases in GHGs and its effect on Antarctic climate, evolution or migration seem unlikely for such long lived species at the remote southern end of the Earth.

  7. Trematode infection causes malformations and population effects in a declining New Zealand fish.

    PubMed

    Kelly, David W; Thomas, Harriet; Thieltges, David W; Poulin, Robert; Tompkins, Daniel M

    2010-03-01

    1. Animal malformations engender wide public and scientific concern because of associated environmental health risks. This is highlighted by increased incidence of limb malformations in amphibians associated with trematode infections and disturbance. Malformations may signal new emerging disease threats, but whether the phenomenon is broadly applicable across taxa, or has population-scale impacts, is unknown. 2. Malformations are widely reported in fish and, until now, have been attributed mainly to contaminants. We tested whether the trematode Telogaster opisthorchis caused severe malformations, leading to population effects, in Galaxias anomalus, a threatened New Zealand freshwater fish. 3. Experimental infection of larval fish caused increasing spinal malformation and mortality with infection intensity that closely matched field patterns. Field malformation frequency peaked in January (65%), before declining sharply in February (25%) and remaining low thereafter. 4. The peak occurred during a 'critical window' of larval development, with the decline coincident with a population crash, indicating that malformation was causing mortality in the field. 5. The occurrence of such critical developmental windows may explain why this mechanism of population impact has been overlooked. With global environmental stressors predicted to enhance trematode infections, our results show that parasite-induced malformation, and its population-scale impacts, could be more widespread than previously considered.

  8. Genetic evidence for long-term population decline in a savannah-dwelling primate: inferences from a hierarchical bayesian model.

    PubMed

    Storz, Jay F; Beaumont, Mark A; Alberts, Susan C

    2002-11-01

    The purpose of this study was to test for evidence that savannah baboons (Papio cynocephalus) underwent a population expansion in concert with a hypothesized expansion of African human and chimpanzee populations during the late Pleistocene. The rationale is that any type of environmental event sufficient to cause simultaneous population expansions in African humans and chimpanzees would also be expected to affect other codistributed mammals. To test for genetic evidence of population expansion or contraction, we performed a coalescent analysis of multilocus microsatellite data using a hierarchical Bayesian model. Markov chain Monte Carlo (MCMC) simulations were used to estimate the posterior probability density of demographic and genealogical parameters. The model was designed to allow interlocus variation in mutational and demographic parameters, which made it possible to detect aberrant patterns of variation at individual loci that could result from heterogeneity in mutational dynamics or from the effects of selection at linked sites. Results of the MCMC simulations were consistent with zero variance in demographic parameters among loci, but there was evidence for a 10- to 20-fold difference in mutation rate between the most slowly and most rapidly evolving loci. Results of the model provided strong evidence that savannah baboons have undergone a long-term historical decline in population size. The mode of the highest posterior density for the joint distribution of current and ancestral population size indicated a roughly eightfold contraction over the past 1,000 to 250,000 years. These results indicate that savannah baboons apparently did not share a common demographic history with other codistributed primate species.

  9. Declines of greater and lesser scaup populations: issues, hypotheses, and research needs

    USGS Publications Warehouse

    Austin, J.E.; Afton, A.D.; Anderson, M.G.; Clark, R.G.; Custer, Christine M.; Lawrence, J.; Pollard, J.B.; Ringelman, J.K.

    2000-01-01

    The population estimate for greater (Aythya marila) and lesser (Aythya affinis) scaup (combined) has declined dramatically since the early 1980s to record lows in 1998. The 1998 estimate of 3.47 million scaup is far below the goal of 6.3 million set in the North American Waterfowl Management Plan (NAWMP), causing concern among biologists and hunters. We summarize issues of concern, hypotheses for factors contributing to the population decline, and research and management needs recommended by participants of the Scaup Workshop, held in September 1999. We believe that contaminants, lower female survival, and reduced recruitment due to changes in food resources or breeding-ground habitats are primary factors contributing to the decline. These factors are not mutually exclusive but likely interact across seasons. Workshop participants identified seven action items. We need to further delineate where declines in breeding populations have occurred, with a primary focus on the western Canadian boreal forest, where declines appear to be most pronounced. Productivity in various areas and habitats throughout the breeding range needs to be assessed by conducting retrospective analyses of existing data and by intensive field studies at broad and local scales. Annual and seasonal survival rates need to be determined in order to assess the role of harvest or natural mortality. Effects of contaminants on reproduction, female body condition, and behavior must be investigated. Use, distribution, and role of food resources relative to body condition and reproduction need to be examined to better understand seasonal dynamics of nutrient reserves and the role in reproductive success. Affiliations among breeding, migration, and wintering areas must be assessed in order to understand differential exposure to harvest or contaminants, and differential reproductive success and recruitment. Biologists and agencies need to gather and improve information needed to manage greater and lesser

  10. Toxicity of two insecticides to California, USA, anurans and its relevance to declining amphibian populations

    USGS Publications Warehouse

    Sparling, D.W.; Fellers, G.M.

    2009-01-01

    Contaminants have been associated with population declines of several amphibian species in California (USA). Pesticides from the Central Valley of California are transported by winds into the Sierra Nevada Mountains and precipitate into wet meadows where amphibians breed. The present study examined the chronic toxicity of two of the insecticides most commonly used in the Central Valley and found in the mountains, chlorpyrifos and endosulfan, to larval Pacific treefrogs (Pseudacris regilla) and foothill yellow-legged frogs (Rana boylii) and discusses the implications of this toxicity to declining amphibian populations. Larvae were exposed to the pesticides from Gosner stages 25 to 26 through metamorphosis. The estimated median lethal concentration (LC50) for chlorpyrifos was 365 ??g/L in P. regilla and 66.5 ??g/L for R. boylii. Time to metamorphosis increased with concentration of chlorpyrifos in both species, and cholinesterase activity declined with exposure concentration in metamorphs of both species at Gosner stages 42 to 46. For endosulfan, the estimated LC50 was 15.6 ??g/L for P. regilla and 0.55 ??g/L for R. boylii. All R. boylii exposed to concentrations of greater than 0.8 ??g/L died before they entered metamorphosis. Pseudacris regilla remains relatively abundant and is broadly distributed throughout California. In contrast, R. boylii is among the species experiencing severe population declines. The present study adds to the increasing evidence that pesticides are very harmful to amphibians living in areas that are miles from sources of pesticide application. ?? 2009 SETAC.

  11. Causes and consequences of marine mammal population declines in southwest Alaska: a food-web perspective.

    PubMed

    Estes, J A; Doak, D F; Springer, A M; Williams, T M

    2009-06-27

    Populations of sea otters, seals and sea lions have collapsed across much of southwest Alaska over the past several decades. The sea otter decline set off a trophic cascade in which the coastal marine ecosystem underwent a phase shift from kelp forests to deforested sea urchin barrens. This interaction in turn affected the distribution, abundance and productivity of numerous other species. Ecological consequences of the pinniped declines are largely unknown. Increased predation by transient (marine mammal-eating) killer whales probably caused the sea otter declines and may have caused the pinniped declines as well. Springer et al. proposed that killer whales, which purportedly fed extensively on great whales, expanded their diets to include a higher percentage of sea otters and pinnipeds following a sharp reduction in great whale numbers from post World War II industrial whaling. Critics of this hypothesis claim that great whales are not now and probably never were an important nutritional resource for killer whales. We used demographic/energetic analyses to evaluate whether or not a predator-prey system involving killer whales and the smaller marine mammals would be sustainable without some nutritional contribution from the great whales. Our results indicate that while such a system is possible, it could only exist under a narrow range of extreme conditions and is therefore highly unlikely.

  12. Causes and consequences of marine mammal population declines in southwest Alaska: a food-web perspective

    PubMed Central

    Estes, J.A.; Doak, D.F.; Springer, A.M.; Williams, T.M.

    2009-01-01

    Populations of sea otters, seals and sea lions have collapsed across much of southwest Alaska over the past several decades. The sea otter decline set off a trophic cascade in which the coastal marine ecosystem underwent a phase shift from kelp forests to deforested sea urchin barrens. This interaction in turn affected the distribution, abundance and productivity of numerous other species. Ecological consequences of the pinniped declines are largely unknown. Increased predation by transient (marine mammal-eating) killer whales probably caused the sea otter declines and may have caused the pinniped declines as well. Springer et al. proposed that killer whales, which purportedly fed extensively on great whales, expanded their diets to include a higher percentage of sea otters and pinnipeds following a sharp reduction in great whale numbers from post World War II industrial whaling. Critics of this hypothesis claim that great whales are not now and probably never were an important nutritional resource for killer whales. We used demographic/energetic analyses to evaluate whether or not a predator–prey system involving killer whales and the smaller marine mammals would be sustainable without some nutritional contribution from the great whales. Our results indicate that while such a system is possible, it could only exist under a narrow range of extreme conditions and is therefore highly unlikely. PMID:19451116

  13. Are declining populations of wild geese in China 'prisoners' of their natural habitats?

    PubMed

    Yu, Hui; Wang, Xin; Cao, Lei; Zhang, Lu; Jia, Qiang; Lee, Hansoo; Xu, Zhenggang; Liu, Guanhua; Xu, Wenbin; Hu, Binhua; Fox, Anthony D

    2017-05-22

    While wild goose populations wintering in North America and Europe are mostly flourishing by exploiting farmland, those in China (which seem confined to natural wetlands) are generally declining. Telemetry devices were attached to 67 wintering wild geese of five different species at three important wetlands in the Yangtze River Floodplain (YRF), China to determine habitat use. 50 individuals of three declining species were almost entirely diurnally confined to natural wetlands; 17 individuals from two species showing stable trends used wetlands 83% and 90% of the time, otherwise resorting to farmland. These results confirm earlier studies linking declines among Chinese wintering geese to natural habitat loss and degradation affecting food supply. These results also contribute to explaining the poor conservation status of Chinese wintering geese compared to the same and other goose species wintering in adjacent Korea and Japan, western Europe and North America, which feed almost entirely on agricultural land, liberating them from winter population limitation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. A plant toxin mediated mechanism for the lag in snowshoe hare population recovery following cyclic declines

    USGS Publications Warehouse

    DeAngelis, Donald L.; Bryant, John P.; Liu, Rongsong; Gourley, Stephen A.; Krebs, Charles J; Reichardt, Paul B

    2015-01-01

    A necessary condition for a snowshoe hare population to cycle is reduced reproduction after the population declines. But the cause of a cyclic snowshoe hare population's reduced reproduction during the low phase of the cycle, when predator density collapses, is not completely understood. We propose that moderate-severe browsing by snowshoe hares upon preferred winter-foods could increase the toxicity of some of the hare's best winter-foods during the following hare low, with the result being a decline in hare nutrition that could reduce hare reproduction. We used a combination of modeling and experiments to explore this hypothesis. Using the shrub birch Betula glandulosa as the plant of interest, the model predicted that browsing by hares during a hare cycle peak, by increasing the toxicity B. glandulosa twigs during the following hare low, could cause a hare population to cycle. The model's assumptions were verified with assays of dammarane triterpenes in segments of B. glandulosa twigs and captive hare feeding experiments conducted in Alaska during February and March 1986. The model's predictions were tested with estimates of hare density and measurements of B. glandulosa twig growth made at Kluane, Yukon from 1988–2008. The empirical tests supported the model's predictions. Thus, we have concluded that a browsing-caused increase in twig toxicity that occurs during the hare cycle's low phase could reduce hare reproduction during the low phase of the hare cycle.

  15. Infection dynamics in frog populations with different histories of decline caused by a deadly disease.

    PubMed

    Sapsford, Sarah J; Voordouw, Maarten J; Alford, Ross A; Schwarzkopf, Lin

    2015-12-01

    Pathogens can drive host population dynamics. Chytridiomycosis is a fungal disease of amphibians that is caused by the fungus Batrachochytrium dendrobatidis (Bd). This pathogen has caused declines and extinctions in some host species whereas other host species coexist with Bd without suffering declines. In the early 1990s, Bd extirpated populations of the endangered common mistfrog, Litoria rheocola, at high-elevation sites, while populations of the species persisted at low-elevation sites. Today, populations have reappeared at many high-elevation sites where they presently co-exist with the fungus. We conducted a capture-mark-recapture (CMR) study of six populations of L. rheocola over 1 year, at high and low elevations. We used multistate CMR models to determine which factors (Bd infection status, site type, and season) influenced rates of frog survival, recapture, infection, and recovery from infection. We observed Bd-induced mortality of individual frogs, but did not find any significant effect of Bd infection on the survival rate of L. rheocola at the population level. Survival and recapture rates depended on site type and season. Infection rate was highest in winter when temperatures were favourable for pathogen growth, and differed among site types. The recovery rate was high (75.7-85.8%) across seasons, and did not differ among site types. The coexistence of L. rheocola with Bd suggests that (1) frog populations are becoming resistant to the fungus, (2) Bd may have evolved lower virulence, or (3) current environmental conditions may be inhibiting outbreaks of the fatal disease.

  16. Life-history traits and population decline of the Atlantic mackerel Scomber scombrusin the Adriatic Sea.

    PubMed

    Meneghesso, C; Riginella, E; La Mesa, M; Donato, F; Mazzoldi, C

    2013-11-01

    This study investigated demographic structure and reproductive characteristics of the Atlantic mackerel Scomber scombrus, in relation to landing trends in the northern-central Adriatic Sea. Results highlighted the occurrence of only small-sized and young-age individuals, and a marked decline from the 1990s to the present in maximum age (from 8 to 3 years) and total length (L(T); from 420 to 360 mm). Fecundity ranged between 40,000 and 190,000 eggs, and was related to female L(T). High levels of atresia implied lower values of actual fecundity. Sexual maturity was attained by 72·8% of individuals in their first year of life at 200 mm. The reduction in maximum L(T) resulted in a marked decline in the population egg production, while the reduction in maximum age implied that females participated in fewer spawning events.

  17. Population declines lead to replicate patterns of internal range structure at the tips of the distribution of the California red-legged frog (Rana draytonii)

    USGS Publications Warehouse

    Richmond, Jonathan Q.; Backlin, Adam R.; Tatarian, Patricia J.; Solvesky, Ben G.; Fisher, Robert N.

    2014-01-01

    Demographic declines and increased isolation of peripheral populations of the threatened California red-legged frog (Rana draytonii) have led to the formation of internal range boundaries at opposite ends of the species’ distribution. While the population genetics of the southern internal boundary has been studied in some detail, similar information is lacking for the northern part of the range. In this study, we used microsatellite and mtDNA data to examine the genetic structuring and diversity of some of the last remaining R. draytonii populations in the northern Sierra Nevada, which collectively form the northern external range boundary. We compared these data to coastal populations in the San Francisco Bay Area, where the species is notably more abundant and still exists throughout much of its historic range. We show that ‘external’ Sierra Nevada populations have lower genetic diversity and are more differentiated from one another than their ‘internal’ Bay Area counterparts. This same pattern was mirrored across the distribution in California, where Sierra Nevada and Bay Area populations had lower allelic variability compared to those previously studied in coastal southern California. This genetic signature of northward range expansion was mirrored in the phylogeography of mtDNA haplotypes; northern Sierra Nevada haplotypes showed greater similarity to haplotypes from the south Coast Ranges than to the more geographically proximate populations in the Bay Area. These data cast new light on the geographic origins of Sierra Nevada R. draytonii populations and highlight the importance of distinguishing the genetic effects of contemporary demographic declines from underlying signatures of historic range expansion when addressing the most immediate threats to population persistence. Because there is no evidence of contemporary gene flow between any of the Sierra Nevada R. draytonii populations, we suggest that management activities should focus on

  18. Mammoth tracks indicate a declining Late Pleistocene population in southwestern Alberta, Canada

    NASA Astrophysics Data System (ADS)

    McNeil, Paul; Hills, L. V.; Kooyman, B.; Tolman, Shayne M.

    2005-05-01

    Much debate has raged over the role that early humans played in this most recent large extinction. Fossil mammoth ( Mammuthus primigenius) footprints were discovered at the St. Mary Reservoir in southwestern Canada (Wally's Beach DhPg-8). They are located in aeolian sediment dated at 11,300-11,000 years BP. By comparing the size distribution of these tracks with those of modern African elephants ( Loxodonta africana), the age distribution of this mammoth population was determined. Containing far fewer juveniles than would be expected for an expanding or stable population, these tracks provide the first evidence that a living mammoth population, coexisting with human inhabitants, was in decline. Additionally, the same site provides corroborating evidence of humans hunting megafauna (horse and bovids). This suggests that humans, in addition to climate change, played a role in the end Pleistocene extinctions in North America.

  19. Winter availability of cereal stubbles attracts declining farmland birds and positively influences breeding population trends

    PubMed Central

    Gillings, Simon; Newson, Stuart E; Noble, David G; Vickery, Juliet A

    2005-01-01

    Many studies have demonstrated the selection of stubble fields by farmland birds in winter, but none have shown whether provisioning of this key habitat positively influences national population trends for widespread farmland birds. We use two complementary extensive bird surveys undertaken at the same localities in summer and winter and show that the area of stubble in winter attracts increased numbers of several bird species of conservation concern. Moreover, for several farmland specialists, the availability of stubble fields in winter positively influenced the 10 year breeding population trend (1994–2003) whereas hedgerow bird species were less affected. For skylarks and yellowhammers, initially negative trends showed recovery with 10–20 ha of stubble per 1 km square. Thus, agri-environment schemes that promote retention of over-winter stubbles will attract birds locally and are capable of reversing current population declines if stubbles are available in sufficient quantity. PMID:15870035

  20. Population and colony-level determinants of tertiary sex ratio in the declining barn swallow.

    PubMed

    Saino, Nicola; Romano, Maria; Rubolini, Diego; Caprioli, Manuela; Ambrosini, Roberto; Boncoraglio, Giuseppe; Canova, Luca

    2013-01-01

    Sex ratio of adults (tertiary sex ratio, TSR) is a major feature of animal populations with consequences for their behaviour, genetic structure and viability. Spatial and temporal variation in TSR occurs within species but the mechanisms behind it are poorly understood. In this long-term study of a declining population of a socially monogamous, colonial, migratory bird, the barn swallow (Hirundo rustica), we first analyzed population-level variation in TSR ( =  proportion of males) of yearlings at sexual maturation in relation to ecological conditions as gauged by annual survival rate of adults. TSR was male-biased both among yearlings and older individuals, but male bias of yearlings was more pronounced after years with larger decline in adult survival. Thus, male offspring were less susceptible to the adverse ecological conditions that cause increased mortality. Dispersal and settling site decisions can have major consequences on fitness via the effects of local TSR on mating and sperm competition. Breeding barn swallows are highly philopatric while natal dispersal is high and, together with mortality, is the main determinant of colony TSR. We thus also investigated the mechanisms of breeding colony choice by yearlings and found that TSR of new-settlers in a given colony and year was negatively predicted by TSR of returning, early arriving older individuals in that year, but not by overall TSR at the colony in the previous year. This suggests that in our male-biased population new-settler males respond to local TSR upon arrival to choose the sites with larger breeding opportunities. Hence, variation in ecological conditions as reflected by adult survival can shift the TSR of individuals recruiting into a local population, with potentially various demographic consequences. However, breeding site choice based on TSR tends to homogenize TSR at a population level likely by facilitating settling of dispersing males in colonies with less male-biased TSR.

  1. Current and Historical Drivers of Landscape Genetic Structure Differ in Core and Peripheral Salamander Populations

    PubMed Central

    Dudaniec, Rachael Y.; Spear, Stephen F.; Richardson, John S.; Storfer, Andrew

    2012-01-01

    With predicted decreases in genetic diversity and greater genetic differentiation at range peripheries relative to their cores, it can be difficult to distinguish between the roles of current disturbance versus historic processes in shaping contemporary genetic patterns. To address this problem, we test for differences in historic demography and landscape genetic structure of coastal giant salamanders (Dicamptodon tenebrosus) in two core regions (Washington State, United States) versus the species' northern peripheral region (British Columbia, Canada) where the species is listed as threatened. Coalescent-based demographic simulations were consistent with a pattern of post-glacial range expansion, with both ancestral and current estimates of effective population size being much larger within the core region relative to the periphery. However, contrary to predictions of recent human-induced population decline in the less genetically diverse peripheral region, there was no genetic signature of population size change. Effects of current demographic processes on genetic structure were evident using a resistance-based landscape genetics approach. Among core populations, genetic structure was best explained by length of the growing season and isolation by resistance (i.e. a ‘flat’ landscape), but at the periphery, topography (slope and elevation) had the greatest influence on genetic structure. Although reduced genetic variation at the range periphery of D. tenebrosus appears to be largely the result of biogeographical history rather than recent impacts, our analyses suggest that inherent landscape features act to alter dispersal pathways uniquely in different parts of the species' geographic range, with implications for habitat management. PMID:22590604

  2. Chytridiomycosis and amphibian population declines continue to spread eastward in Panama.

    PubMed

    Woodhams, Douglas C; Kilburn, Vanessa L; Reinert, Laura K; Voyles, Jamie; Medina, Daniel; Ibáñez, Roberto; Hyatt, Alex D; Boyle, Donna G; Pask, James D; Green, David M; Rollins-Smith, Louise A

    2008-09-01

    Chytridiomycosis is a globally emerging disease of amphibians and the leading cause of population declines and extirpations at species-diverse montane sites in Central America. We continued long-term monitoring efforts for the presence of the fungal pathogen Batrachochytrium dendrobatidis (Bd) and for amphibian populations at two sites in western Panama, and we began monitoring at three new sites to the east. Population declines associated with chytridiomycosis emergence were detected at Altos de Campana National Park. We also detected Bd in three species east of the Panama Canal at Soberanía National Park, and prevalence data suggests that Bd may be enzootic in the lowlands of the park. However, no infected frogs were found further east at Tortí (prevalence <7.5% with 95% confidence). Our results suggest that Panama's diverse and not fully described amphibian communities east of the canal are at risk. Precise predictions of future disease emergence events are not possible until factors underlying disease emergence, such as dispersal, are understood. However, if the fungal pathogen spreads in a pattern consistent with previous disease events in Panama, then detection of Bd at Tortí and other areas east of the Panama Canal is imminent. Therefore, development of new management strategies and increased precautions for tourism, recreation, and biology are urgently needed.

  3. What caused the population decline of the Bridled White-eye on Rota, Mariana Islands?

    USGS Publications Warehouse

    Fancy, Steven G.; Snetsinger, Thomas J.

    2001-01-01

    The Bridled White-eye (Zosterops conspicillatus rotensis) was Once thought to be common and widespread on Rota, Commonwealth of the Northern Mariana Islands, but is now restricted to several patches of native limestone forest in and adjacent to the Sabana region. Surveys conducted in 1990 indicated that the population had declined by 87% between 1982 and 1990 for unknown reasons. The low density and restricted habitat association of the Bridled White-eye on Rota contrasts with the situation on Saipan, Tinian, Agiguan, and formerly on Guam, where the Bridled White-eye is the most common forest bird and occurs at all elevations and in all habitat types. We surveyed the entire range of the Rota Bridled White-eye in 1996 to estimate its current numbers and distribution. We also reviewed existing information on the white-eye and evaluated potential causes of its decline, including predation by Black Drongos (Dicrurus macrocercus), rats (Rattus spp.), and the brown tree snake Boiga irregularis); pesticides; avian disease; and habitat loss and alteration. We found that 94% of the extant population of 1,165 white-eyes on Rota was restricted to four patches of old-growth, native limestone forest covering only 259 ha. We believe that the population decline and current localized distribution is primarily a result of habitat changes due to agricultural development and typhoons, but the absence of white-eyes from several stands of native forest above 200 m remains unexplained. The Rota white-eye may be a different species from white-eyes found on Saipan, Tinian, Agiguan, and Guam, with different habitat preferences.

  4. Assessment of blood lead level declines in an area of historical mining with a holistic remediation and abatement program.

    PubMed

    Schoof, Rosalind A; Johnson, Dina L; Handziuk, Emma R; Landingham, Cynthia Van; Feldpausch, Alma M; Gallagher, Alexa E; Dell, Linda D; Kephart, Amy

    2016-10-01

    Lead exposure and blood lead levels (BLLs) in the United States have declined dramatically since the 1970s as many widespread lead uses have been discontinued. Large scale mining and mineral processing represents an additional localized source of potential lead exposure in many historical mining communities, such as Butte, Montana. After 25 years of ongoing remediation efforts and a residential metals abatement program that includes blood lead monitoring of Butte children, examination of blood lead trends offers a unique opportunity to assess the effectiveness of Butte's lead source and exposure reduction measures. This study examined BLL trends in Butte children ages 1-5 (n= 2796) from 2003-2010 as compared to a reference dataset matched for similar demographic characteristics over the same period. Blood lead differences across Butte during the same period are also examined. Findings are interpreted with respect to effectiveness of remediation and other factors potentially contributing to ongoing exposure concerns. BLLs from Butte were compared with a reference dataset (n=2937) derived from the National Health and Nutrition Examination Survey. The reference dataset was initially matched for child age and sample dates. Additional demographic factors associated with higher BLLs were then evaluated. Weights were applied to make the reference dataset more consistent with the Butte dataset for the three factors that were most disparate (poverty-to-income ratio, house age, and race/ethnicity). A weighted linear mixed regression model showed Butte geometric mean BLLs were higher than reference BLLs for 2003-2004 (3.48vs. 2.05µg/dL), 2005-2006 (2.65vs. 1.80µg/dL), and 2007-2008 (2.2vs. 1.72µg/dL), but comparable for 2009-2010 (1.53vs. 1.51µg/dL). This trend suggests that, over time, the impact of other factors that may be associated with Butte BLLs has been reduced. Neighborhood differences were examined by dividing the Butte dataset into the older area called "Uptown

  5. Employment problems under declining population growth rates and structural change: the case of Yugoslavia.

    PubMed

    Macura, M

    1974-01-01

    The case of Yugoslavia since World War 2 generally confirms the find ings of Coale and Hoover some 15 years ago that a declining population gives a developing society a chance to grow at a more rapid rate because less of the gross national product is devoted to merely maintaining the status quo. However, until recently insufficient attention was paid to the long-term effects of rapid population growth plus underdevelopment, namely, surplus labor and unemployment. Yugoslavia is currently suffereing the aftereffects of a history of labor surplus caused by high birthrates, especially in the southern Moslem regions. The birthrate was as high as 35/1000 until 1927, took a downward turn during the depression, falling to 26/1000 in 1939, became even more depressed during World War 2, then reached 26-30/1000 in the postwar years. After 1957 a steady decline set in. The rate was around 18/1000 in the early 1970s. Because of the underdeveloped, highly agrarian economy, Yugoslavia has traditionally been a source of abundant labor and emigration. Statistical data has been either nonexistent or unreliable, but there have been self-evident differences in the size of individual cohorts which have had definite bearing on the working-age population. Following World War 2 the country changed from a predominantly peasant, subsistence economy to an industrial socialist society. There has been a steady decline in the participation rate in the work force, from an estimated 46.5% in 1948 to 43.3% in 1971, primarily due to increased education, declining child labor, and greater retirement among older workers. However, the growth of the working-age group was faster than that of the total population because of the high postwar birthrates. Th ere was significant increase in employment from 1,517,000 in 1948 to 4,034,000 in 1971. At the same time the agricultural labor force decrea sed from 70% of total employment to 48%. Despite the industrial growth, in 1971 there were over 290

  6. Extensive population decline in the Tasmanian devil predates European settlement and devil facial tumour disease

    PubMed Central

    Brüniche-Olsen, Anna; Jones, Menna E.; Austin, Jeremy J.; Burridge, Christopher P.; Holland, Barbara R.

    2014-01-01

    The Tasmanian devil (Sarcophilus harrisii) was widespread in Australia during the Late Pleistocene but is now endemic to the island of Tasmania. Low genetic diversity combined with the spread of devil facial tumour disease have raised concerns for the species’ long-term survival. Here, we investigate the origin of low genetic diversity by inferring the species' demographic history using temporal sampling with summary statistics, full-likelihood and approximate Bayesian computation methods. Our results show extensive population declines across Tasmania correlating with environmental changes around the last glacial maximum and following unstable climate related to increased ‘El Niño–Southern Oscillation’ activity. PMID:25376800

  7. Temporal cognitive decline associated with exposure to infectious agents in a population-based, aging cohort

    PubMed Central

    Nimgaonkar, Vishwajit L; Yolken, Robert H; Wang, Tianxiu; Chang, Chung-Chou H.; McClain, Lora; McDade, Eric; Snitz, Beth E.; Ganguli, Mary

    2015-01-01

    Background Numerous cross-sectional studies have related exposure to neurotropic infectious agents with cognitive dysfunction in older adults, but the temporal sequence is uncertain. Methods In a representative, well-characterized, population-based aging cohort, we determined whether the temporal trajectories of multiple cognitive domains are associated with exposure to cytomegalovirus (CMV), Herpes Simplex virus, type 1 (HSV-1), Herpes Simplex virus, type 2 (HSV-2) or Toxoplasma gondii (TOX). Complex attention, executive functions, memory, language, and visuospatial function were assessed annually for five years among consenting individuals. Study entry IgG antibody titers indexing exposure to each infectious agent were examined in relation to slopes of subsequent temporal cognitive decline using multiple linear regressions adjusted for potential confounders. Results The IgG levels for HSV-2 were significantly associated with baseline cognitive domain scores (N=1022 participants). Further, the IgG levels for HSV-2, TOX and CMV, but not HSV-1 were significantly associated with greater temporal cognitive decline that varied by type of infection. Conclusions Exposure to CMV, HSV-2, or TOX is associated with cognitive deterioration in older individuals, independent of general age related variables. An increased understanding of the role of infectious agents in cognitive decline may lead to new methods for its prevention and treatment. PMID:26710257

  8. Chronic Wasting Disease Drives Population Decline of White-Tailed Deer.

    PubMed

    Edmunds, David R; Kauffman, Matthew J; Schumaker, Brant A; Lindzey, Frederick G; Cook, Walter E; Kreeger, Terry J; Grogan, Ronald G; Cornish, Todd E

    2016-01-01

    Chronic wasting disease (CWD) is an invariably fatal transmissible spongiform encephalopathy of white-tailed deer, mule deer, elk, and moose. Despite a 100% fatality rate, areas of high prevalence, and increasingly expanding geographic endemic areas, little is known about the population-level effects of CWD in deer. To investigate these effects, we tested the null hypothesis that high prevalence CWD did not negatively impact white-tailed deer population sustainability. The specific objectives of the study were to monitor CWD-positive and CWD-negative white-tailed deer in a high-prevalence CWD area longitudinally via radio-telemetry and global positioning system (GPS) collars. For the two populations, we determined the following: a) demographic and disease indices, b) annual survival, and c) finite rate of population growth (λ). The CWD prevalence was higher in females (42%) than males (28.8%) and hunter harvest and clinical CWD were the most frequent causes of mortality, with CWD-positive deer over-represented in harvest and total mortalities. Survival was significantly lower for CWD-positive deer and separately by sex; CWD-positive deer were 4.5 times more likely to die annually than CWD-negative deer while bucks were 1.7 times more likely to die than does. Population λ was 0.896 (0.859-0.980), which indicated a 10.4% annual decline. We show that a chronic disease that becomes endemic in wildlife populations has the potential to be population-limiting and the strong population-level effects of CWD suggest affected populations are not sustainable at high disease prevalence under current harvest levels.

  9. Chronic wasting disease drives population decline of white-tailed deer

    USGS Publications Warehouse

    Edmunds, David; Kauffman, Matthew J.; Schumaker, Brant; Lindzey, Frederick G.; Cook, Walter; Kreeger, Terry J.; Grogan, Ronald; Cornish, Todd

    2016-01-01

    Chronic wasting disease (CWD) is an invariably fatal transmissible spongiform encephalopathy of white-tailed deer, mule deer, elk, and moose. Despite a 100% fatality rate, areas of high prevalence, and increasingly expanding geographic endemic areas, little is known about the population-level effects of CWD in deer. To investigate these effects, we tested the null hypothesis that high prevalence CWD did not negatively impact white-tailed deer population sustainability. The specific objectives of the study were to monitor CWD-positive and CWD-negative white-tailed deer in a high-prevalence CWD area longitudinally via radio-telemetry and global positioning system (GPS) collars. For the two populations, we determined the following: a) demographic and disease indices, b) annual survival, and c) finite rate of population growth (λ). The CWD prevalence was higher in females (42%) than males (28.8%) and hunter harvest and clinical CWD were the most frequent causes of mortality, with CWD-positive deer over-represented in harvest and total mortalities. Survival was significantly lower for CWD-positive deer and separately by sex; CWD-positive deer were 4.5 times more likely to die annually than CWD-negative deer while bucks were 1.7 times more likely to die than does. Population λ was 0.896 (0.859–0.980), which indicated a 10.4% annual decline. We show that a chronic disease that becomes endemic in wildlife populations has the potential to be population-limiting and the strong population-level effects of CWD suggest affected populations are not sustainable at high disease prevalence under current harvest levels.

  10. Chronic Wasting Disease Drives Population Decline of White-Tailed Deer

    PubMed Central

    Kauffman, Matthew J.; Schumaker, Brant A.; Lindzey, Frederick G.; Cook, Walter E.; Kreeger, Terry J.; Grogan, Ronald G.; Cornish, Todd E.

    2016-01-01

    Chronic wasting disease (CWD) is an invariably fatal transmissible spongiform encephalopathy of white-tailed deer, mule deer, elk, and moose. Despite a 100% fatality rate, areas of high prevalence, and increasingly expanding geographic endemic areas, little is known about the population-level effects of CWD in deer. To investigate these effects, we tested the null hypothesis that high prevalence CWD did not negatively impact white-tailed deer population sustainability. The specific objectives of the study were to monitor CWD-positive and CWD-negative white-tailed deer in a high-prevalence CWD area longitudinally via radio-telemetry and global positioning system (GPS) collars. For the two populations, we determined the following: a) demographic and disease indices, b) annual survival, and c) finite rate of population growth (λ). The CWD prevalence was higher in females (42%) than males (28.8%) and hunter harvest and clinical CWD were the most frequent causes of mortality, with CWD-positive deer over-represented in harvest and total mortalities. Survival was significantly lower for CWD-positive deer and separately by sex; CWD-positive deer were 4.5 times more likely to die annually than CWD-negative deer while bucks were 1.7 times more likely to die than does. Population λ was 0.896 (0.859–0.980), which indicated a 10.4% annual decline. We show that a chronic disease that becomes endemic in wildlife populations has the potential to be population-limiting and the strong population-level effects of CWD suggest affected populations are not sustainable at high disease prevalence under current harvest levels. PMID:27575545

  11. Experts correctly describe demography associated with historical decline of the endangered Indiana bat, but not recent period of stationarity

    USGS Publications Warehouse

    Thogmartin, Wayne E.; Sanders-Reed, Carol A.; Szymanski, Jennifer; Pruitt, Lori; Runge, Michael C.

    2017-01-01

    Demographic characteristics of bats are often insufficiently described for modeling populations. In data poor situations, experts are often relied upon for characterizing ecological systems. In concert with the development of a matrix model describing Indiana bat (Myotis sodalis) demography, we elicited estimates for parameterizing this model from 12 experts. We conducted this elicitation in two stages, requesting expert values for 12 demographic rates. These rates were adult and juvenile seasonal (winter, summer, fall) survival rates, pup survival in fall, and propensity and success at breeding. Experts were most in agreement about adult fall survival (3% Coefficient of Variation) and least in agreement about propensity of juveniles to breed (37% CV). The experts showed greater concordance for adult ( mean CV, adult = 6.2%) than for juvenile parameters ( mean CV, juvenile = 16.4%), and slightly more agreement for survival (mean CV, survival = 9.8%) compared to reproductive rates ( mean CV, reproduction = 15.1%). However, survival and reproduction were negatively and positively biased, respectively, relative to a stationary dynamic. Despite the species exhibiting near stationary dynamics for two decades prior to the onset of a potential extinction-causing agent, white-nose syndrome, expert estimates indicated a population decline of -11% per year (95% CI = -2%, -20%); quasi-extinction was predicted within a century ( mean = 61 years to QE, range = 32, 97) by 10 of the 12 experts. Were we to use these expert estimates in our modeling efforts, we would have errantly trained our models to a rapidly declining demography asymptomatic of recent demographic behavior. While experts are sometimes the only source of information, a clear understanding of the temporal and spatial context of the information being elicited is necessary to guard against wayward predictions.

  12. Cognitive decline in short and long sleepers: A prospective population-based study (NEDICES)

    PubMed Central

    Benito-León, Julián; Louis, Elan D.; Bermejo-Pareja, Félix

    2013-01-01

    Background It is not clear whether cognitive decline progresses more quickly in long sleepers than in short sleepers or than in participants with usual sleep duration. We assessed cognitive decline as a function of self-reported sleep duration in a prospective population-based cohort (NEDICES). Methods Participants were evaluated at baseline and 3 years later. Baseline demographic variables were recorded and participants indicated their daily sleep usual duration as the sum of nighttime sleep and daytime napping. The average daily total usual sleep duration was grouped into three categories: ≤5 hours (short sleepers), 6 to 8 hours (reference category), and ≥9 hours (long sleepers). At baseline and at follow-up, a 37-item version of the Mini-Mental State Examination (37-MMSE) was administered. Results The final sample, 2,715 participants (72.9±6.1 years), comprised 298 (11%) short sleepers, 1,086 (40%) long sleepers, and 1,331 (49%) in the reference group (6 to 8 hours). During the three year follow-up period, the 37-MMSE declined by 0.5±4.0 points in short sleepers, 0.6±4.3 points in long sleepers, and 0.2±3.8 points in the reference group (p=0.08). The difference between short sleepers and the reference group was not significant (p=0.142); however, the difference between long sleepers and the reference group was significant (p=0.040). In analyses adjusted for baseline age and other potential confounders, this difference remained robust. Conclusions In this study, cognitive test scores among long sleepers declined more rapidly than observed in a reference group. Additional studies are needed to confirm these results. PMID:24094933

  13. Agriculture modifies the seasonal decline of breeding success in a tropical wild bird population

    PubMed Central

    Cartwright, Samantha J; Nicoll, Malcolm A C; Jones, Carl G; Tatayah, Vikash; Norris, Ken

    2014-01-01

    Habitat conversion for agriculture is a major driver of biodiversity loss, but our understanding of the demographic processes involved remains poor. We typically investigate the impacts of agriculture in isolation even though populations are likely to experience multiple, concurrent changes in the environment (e.g. land and climate change). Drivers of environmental change may interact to affect demography, but the mechanisms have yet to be explored fully in wild populations. Here, we investigate the mechanisms linking agricultural land use with breeding success using long-term data for the formerly Critically Endangered Mauritius kestrel Falco punctatus, a tropical forest specialist that also occupies agricultural habitats. We specifically focused on the relationship between breeding success, agriculture and the timing of breeding because the latter is sensitive to changes in climatic conditions (spring rainfall) and enables us to explore the interactive effects of different (land and climate) drivers of environmental change. Breeding success, measured as egg survival to fledging, declines seasonally in this population, but we found that the rate of this decline became increasingly rapid as the area of agriculture around a nest site increased. If the relationship between breeding success and agriculture was used in isolation to estimate the demographic impact of agriculture, it would significantly under-estimate breeding success in dry (early) springs and over-estimate breeding success in wet (late) springs. Analysis of prey delivered to nests suggests that the relationship between breeding success and agriculture might be due, in part, to spatial variation in the availability of native, arboreal geckos. Synthesis and applications. Agriculture modifies the seasonal decline in breeding success in this population. As springs are becoming wetter in our study area and since the kestrels breed later in wetter springs, the impact of agriculture on breeding success will

  14. Assay dependence of Brucella antibody prevalence in a declining Alaskan harbor seal (Phoca vitulina) population

    PubMed Central

    2013-01-01

    Background Brucella is a group of bacteria that causes brucellosis, which can affect population health and reproductive success in many marine mammals. We investigated the serological prevalence of antibodies against Brucella bacteria in a declining harbor seal population in Glacier Bay National Park, Alaska. Results Prevalence ranged from 16 to 74 percent for those tests detecting antibodies, indicating that harbor seals in Glacier Bay have been exposed to Brucella bacteria. However, the actual level of serological prevalence could not be determined because results were strongly assay-dependent. Conclusions This study reinforces the need to carefully consider assay choice when comparing different studies on the prevalence of anti–Brucella antibodies in pinnipeds and further highlights the need for species- or taxon-specific assay validation for both pathogen and host species. PMID:23324565

  15. Garter snakes distributions in high elevation aquatic ecosystems: Is there a link with declining amphibian populations and nonnative trout introductions?

    Treesearch

    K.R. Matthews; R.A. Knapp; K.L. Pope

    2002-01-01

    ABSTRACT.—The dramatic amphibian population declines reported worldwide likely have important effects on their predators. In the Sierra Nevada, where amphibian declines are well documented and some are closely tied to the introduction of nonnative trout, the mountain garter snake, Thamnophis elegans elegans, preys predominately on amphibians. We surveyed 2103 high-...

  16. Evidence for declines in human population densities during the early Upper Paleolithic in western Europe

    PubMed Central

    Morin, Eugène

    2008-01-01

    In western Europe, the Middle to Upper Paleolithic (M/UP) transition, dated between ≈35,000 and ≈40,000 radiocarbon years, corresponded to a period of major human biological and cultural changes. However, information on human population densities is scarce for that period. New faunal data from the high-resolution record of Saint-Césaire, France, indicate an episode of significant climatic deterioration during the early Upper Paleolithic (EUP), which also was associated with a reduction in mammalian species diversity. High correlations between ethnographic data and mammalian species diversity suggest that this shift decreased human population densities. Reliance on reindeer (Rangifer tarandus), a highly fluctuating resource, would also have promoted declines in human population densities. These data suggest that the EUP represented for humans a period of significant niche contraction in western Europe. In this context, the possibility that a modern human expansion occurred in this region seems low. Instead, it is suggested that population bottlenecks, genetic drift, and gene flow prevailed over human population replacement as mechanisms of evolution in humans during the EUP. PMID:18172204

  17. Vitamin D as a marker of cognitive decline in elderly Indian population

    PubMed Central

    Vedak, Tejal Kanhaiya; Ganwir, Vaishali; Shah, Arun B.; Pinto, Charles; Lele, Vikram R.; Subramanyam, Alka; Shah, Hina; Deo, Sudha Shrikant

    2015-01-01

    Objectives: Very few studies in India have addressed the role of vitamin D in cognitive function. The present study was conducted to assess the serum levels of 25-hydroxyvitamin D (25(OH)D) and its association with markers of cognitive impairment and homocysteine levels in the elderly Indian population. Materials and Methods: The study population consisted of patients with dementia (Group A, n = 32), mild cognitive impairment (MCI; Group B, n = 24), and elderly age-matched controls (Group C, n = 30). Measurement of serum levels of 25(OH)D and total homocysteine were done. Results: Significant decreased concentration of 25(OH)D and increased concentration of homocysteine was observed. Association of serum levels of vitamin D with markers of cognitive decline as well as serum homocysteine levels was observed in patients with dementia and MCI when compared to controls. Conclusion: Correlation of vitamin D with markers of cognitive decline and homocysteine opens a new door for early diagnosis of cognitive impairment. PMID:26425010

  18. Modeling routes of chronic wasting disease transmission: Environmental prion persistence promotes deer population decline and extinction

    USGS Publications Warehouse

    Almberg, Emily S.; Cross, Paul C.; Johnson, Christopher J.; Heisey, Dennis M.; Richards, Bryan J.

    2011-01-01

    Chronic wasting disease (CWD) is a fatal disease of deer, elk, and moose transmitted through direct, animal-to-animal contact, and indirectly, via environmental contamination. Considerable attention has been paid to modeling direct transmission, but despite the fact that CWD prions can remain infectious in the environment for years, relatively little information exists about the potential effects of indirect transmission on CWD dynamics. In the present study, we use simulation models to demonstrate how indirect transmission and the duration of environmental prion persistence may affect epidemics of CWD and populations of North American deer. Existing data from Colorado, Wyoming, and Wisconsin's CWD epidemics were used to define plausible short-term outcomes and associated parameter spaces. Resulting long-term outcomes range from relatively low disease prevalence and limited host-population decline to host-population collapse and extinction. Our models suggest that disease prevalence and the severity of population decline is driven by the duration that prions remain infectious in the environment. Despite relatively low epidemic growth rates, the basic reproductive number, R0, may be much larger than expected under the direct-transmission paradigm because the infectious period can vastly exceed the host's life span. High prion persistence is expected to lead to an increasing environmental pool of prions during the early phases (i.e. approximately during the first 50 years) of the epidemic. As a consequence, over this period of time, disease dynamics will become more heavily influenced by indirect transmission, which may explain some of the observed regional differences in age and sex-specific disease patterns. This suggests management interventions, such as culling or vaccination, will become increasingly less effective as CWD epidemics progress.

  19. Climate warming, ecological mismatch at arrival and population decline in migratory birds.

    PubMed

    Saino, Nicola; Ambrosini, Roberto; Rubolini, Diego; von Hardenberg, Jost; Provenzale, Antonello; Hüppop, Kathrin; Hüppop, Ommo; Lehikoinen, Aleksi; Lehikoinen, Esa; Rainio, Kalle; Romano, Maria; Sokolov, Leonid

    2011-03-22

    Climate is changing at a fast pace, causing widespread, profound consequences for living organisms. Failure to adjust the timing of life-cycle events to climate may jeopardize populations by causing ecological mismatches to the life cycle of other species and abiotic factors. Population declines of some migratory birds breeding in Europe have been suggested to depend on their inability to adjust migration phenology so as to keep track of advancement of spring events at their breeding grounds. In fact, several migrants have advanced their spring arrival date, but whether such advancement has been sufficient to compensate for temporal shift in spring phenophases or, conversely, birds have become ecologically mismatched, is still an unanswered question, with very few exceptions. We used a novel approach based on accumulated winter and spring temperatures (degree-days) as a proxy for timing of spring biological events to test if the progress of spring at arrival to the breeding areas by 117 European migratory bird species has changed over the past five decades. Migrants, and particularly those wintering in sub-Saharan Africa, now arrive at higher degree-days and may have therefore accumulated a 'thermal delay', thus possibly becoming increasingly mismatched to spring phenology. Species with greater 'thermal delay' have shown larger population decline, and this evidence was not confounded by concomitant ecological factors or by phylogenetic effects. These findings provide general support to the largely untested hypotheses that migratory birds are becoming ecologically mismatched and that failure to respond to climate change can have severe negative impacts on their populations. The novel approach we adopted can be extended to the analysis of ecological consequences of phenological response to climate change by other taxa.

  20. Activity patterns and time budgets of the declining sea otter population at Amchitka Island, Alaska

    USGS Publications Warehouse

    Gelatt, Thomas S.; Siniff, Donald B.; Estes, James A.

    2002-01-01

    Time budgets of predators may reflect population status if time spent foraging varies with local prey abun- dance. We assumed that the sea otter (Enhydra lutris) population at Amchitka Island, Alaska, USA, had been at equilibrium since the early 1960s and collected time budgets of otters to be used to represent future conditions of currently expanding sea otter populations. We used radiotelemetry to monitor activity-time budgets of otters from August 1992 to March 1994. Sea otter activity was directly linked to sex, age, weather condition, season, and time of day. Sea otters differed in percent time foraging among cohorts but not within cohorts. Percent time foraging ranged from 21% for females with very young (≤ 3weeks of age) dependent pups to 52% for females with old (≥10 weeks of age) pups. Otters foraged more and hauled out more as local sea conditions worsened. Adult males spent less time foraging during winter and spring, consistent with seasonal changes in prey selection. Time spent for- aging was similar to that reported for otters in California and an established population in Prince William Sound, Alaska, but greater than that of otters in recently established populations in Oregon and Alaska. Despite current evidence indicating that the population was in decline during our study, we were unable to recognize this change using time budgets. Our results illustrate the importance of stratifying analyses of activity patterns by age and sex cohorts and the complexity inherent in comparisons of behavioral data between different populations relying on distinct prey bases.

  1. Population persistence in Florida torreya: Comparing modeled projections of a declining coniferous tree

    USGS Publications Warehouse

    Schwartz, Mark W.; Hermann, Sharon M.; van Mantgem, Phillip J.

    2000-01-01

    The Florida torreya (  Torreya taxifolia) is a coniferous tree endemic to a 35-km stretch of bluffs and ravines along the east side of the Apalachicola River in northern Florida and southern Georgia. This formerly locally abundant tree has declined as a result of disease during the 1950s and is on the U.S. endangered species list. With no seed production in the wild, this species is headed toward extinction. We conducted a survey on roughly 200 trees from 1988 to 1996 and used these data to estimate the likelihood of population persistence during the next several decades. We compared a stage-class transition matrix model ( RAMAS) and an individual-based stochastic model ( TORSIM) of growth and mortality to project future populations. Given the current lack of seed production in the wild, all models predict extinction. The question of concern is the imminence of this predicted extinction. Differing predicted times to extinction would suggest different immediate management recommendations. Both models predicted an over 90% likelihood of persistence during the next 50 years. Predictions differed in that the transition matrix model was less optimistic than the individual-based model regarding persistence. Model sensitivity analysis showed that the results were robust to significant decreases in growth and sprouting probabilities. Submodels identified different persistence likelihoods in different populations. Nonetheless, unless management of the population can facilitate maturation and seed production, extinction of this species in the wild is inevitable.

  2. Decline in admissions for childhood asthma, a 26-year period population-based study.

    PubMed

    Mikalsen, Ingvild Bruun; Skeiseid, Liliane; Tveit, Line Merete; Engelsvold, David Hugo; Øymar, Knut

    2015-12-01

    The prevalence of childhood asthma has increased, although the rate of hospitalization for asthma seems to decrease. In Norway, the rate of hospital admission for childhood asthma from 1984 to 2000 increased. The aim of this study was to assess further trends in hospital admissions for childhood asthma up to 2010. A population-based study including children 1-13 yrs of age hospitalized for asthma during six periods from 1984/1985 to 2009/2010 in Rogaland, Norway, was performed. Medical records from 1536 admissions (1050 children) were studied; and gender, age, number of admissions, length of hospital stay, medications and symptoms were recorded. For all age groups, the rate of admissions per 10.000 increased from 20.1 in 1984/85 to 33.7 in 1989/90, but declined to 14.4 in 2009/2010. Rates were highest in boys (OR 1.87; 95% CI: 1.69, 2.09), younger age groups (OR 2.51; 2.38, 2.64) and decreased from 1984 to 2010 (OR 0.92; 0.88, 0.94). The rates of readmissions were higher than for primary admissions (OR 1.33; 1.19, 1.47). From 1984 to 2010, there was an increased use of inhaled corticosteroids prior to admission (6 to 51%) and started at discharge (7 to 37%), and systemic steroids given during admission (19 to 83%). There has been a substantial decline in the rate of hospital admissions for childhood asthma after 1989/1990, with major differences between age groups and genders. The decline could be due to improved care of children with asthma or a real reduction in asthma exacerbations. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. When Is a Species Declining? Optimizing Survey Effort to Detect Population Changes in Reptiles

    PubMed Central

    Sewell, David; Guillera-Arroita, Gurutzeta; Griffiths, Richard A.; Beebee, Trevor J. C.

    2012-01-01

    Biodiversity monitoring programs need to be designed so that population changes can be detected reliably. This can be problematical for species that are cryptic and have imperfect detection. We used occupancy modeling and power analysis to optimize the survey design for reptile monitoring programs in the UK. Surveys were carried out six times a year in 2009–2010 at multiple sites. Four out of the six species – grass snake, adder, common lizard, slow-worm –were encountered during every survey from March-September. The exceptions were the two rarest species ­– sand lizard and smooth snake – which were not encountered in July 2009 and March 2010 respectively. The most frequently encountered and most easily detected species was the slow-worm. For the four widespread reptile species in the UK, three to four survey visits that used a combination of directed transect walks and artificial cover objects resulted in 95% certainty that a species would be detected if present. Using artificial cover objects was an effective detection method for most species, considerably increased the detection rate of some, and reduced misidentifications. To achieve an 85% power to detect a decline in any of the four widespread species when the true decline is 15%, three surveys at a total of 886 sampling sites, or four surveys at a total of 688 sites would be required. The sampling effort needed reduces to 212 sites surveyed three times, or 167 sites surveyed four times, if the target is to detect a true decline of 30% with the same power. The results obtained can be used to refine reptile survey protocols in the UK and elsewhere. On a wider scale, the occupancy study design approach can be used to optimize survey effort and help set targets for conservation outcomes for regional or national biodiversity assessments. PMID:22937044

  4. Can Individual and Social Patterns of Resource Use Buffer Animal Populations against Resource Decline?

    PubMed Central

    Banks, Sam C.; Lindenmayer, David B.; Wood, Jeff T.; McBurney, Lachlan; Blair, David; Blyton, Michaela D. J.

    2013-01-01

    Species in many ecosystems are facing declines of key resources. If we are to understand and predict the effects of resource loss on natural populations, we need to understand whether and how the way animals use resources changes under resource decline. We investigated how the abundance of arboreal marsupials varies in response to a critical resource, hollow-bearing trees. Principally, we asked what mechanisms mediate the relationship between resources and abundance? Do animals use a greater or smaller proportion of the remaining resource, and is there a change in cooperative resource use (den sharing), as the availability of hollow trees declines? Analyses of data from 160 sites surveyed from 1997 to 2007 showed that hollow tree availability was positively associated with abundance of the mountain brushtail possum, the agile antechinus and the greater glider. The abundance of Leadbeater’s possum was primarily influenced by forest age. Notably, the relationship between abundance and hollow tree availability was significantly less than 1∶1 for all species. This was due primarily to a significant increase by all species in the proportional use of hollow-bearing trees where the abundance of this resource was low. The resource-sharing response was weaker and inconsistent among species. Two species, the mountain brushtail possum and the agile antechinus, showed significant but contrasting relationships between the number of animals per occupied tree and hollow tree abundance. The discrepancies between the species can be explained partly by differences in several aspects of the species’ biology, including body size, types of hollows used and social behaviour as it relates to hollow use. Our results show that individual and social aspects of resource use are not always static in response to resource availability and support the need to account for dynamic resource use patterns in predictive models of animal distribution and abundance. PMID:23320100

  5. Can individual and social patterns of resource use buffer animal populations against resource decline?

    PubMed

    Banks, Sam C; Lindenmayer, David B; Wood, Jeff T; McBurney, Lachlan; Blair, David; Blyton, Michaela D J

    2013-01-01

    Species in many ecosystems are facing declines of key resources. If we are to understand and predict the effects of resource loss on natural populations, we need to understand whether and how the way animals use resources changes under resource decline. We investigated how the abundance of arboreal marsupials varies in response to a critical resource, hollow-bearing trees. Principally, we asked what mechanisms mediate the relationship between resources and abundance? Do animals use a greater or smaller proportion of the remaining resource, and is there a change in cooperative resource use (den sharing), as the availability of hollow trees declines? Analyses of data from 160 sites surveyed from 1997 to 2007 showed that hollow tree availability was positively associated with abundance of the mountain brushtail possum, the agile antechinus and the greater glider. The abundance of Leadbeater's possum was primarily influenced by forest age. Notably, the relationship between abundance and hollow tree availability was significantly less than 1:1 for all species. This was due primarily to a significant increase by all species in the proportional use of hollow-bearing trees where the abundance of this resource was low. The resource-sharing response was weaker and inconsistent among species. Two species, the mountain brushtail possum and the agile antechinus, showed significant but contrasting relationships between the number of animals per occupied tree and hollow tree abundance. The discrepancies between the species can be explained partly by differences in several aspects of the species' biology, including body size, types of hollows used and social behaviour as it relates to hollow use. Our results show that individual and social aspects of resource use are not always static in response to resource availability and support the need to account for dynamic resource use patterns in predictive models of animal distribution and abundance.

  6. Habitat split as a cause of local population declines of amphibians with aquatic larvae.

    PubMed

    Becker, C Guilherme; Fonseca, Carlos R; Haddad, Célio F B; Prado, Paulo I

    2010-02-01

    Most amphibian species have biphasic life histories and undergo an ontogenetic shift from aquatic to terrestrial habitats. In deforested landscapes, streams and forest fragments are frequently disjunct, jeopardizing the life cycle of forest-associated amphibians with aquatic larvae. We tested the impact of habitat split--defined as human-induced disconnection between habitats used by different life-history stages of a species--on four forest-associated amphibian species in a severely fragmented landscape of the Brazilian Atlantic Forest. We surveyed amphibians in forest fragments with and without streams (referred to as wet and dry fragments, respectively), including the adjacent grass-field matrix. Our comparison of capture rates in dry fragments and nearby streams in the matrix allowed us to evaluate the number of individuals that engaged in high-risk migrations through nonforested habitats. Adult amphibians moved from dry fragments to matrix streams at the beginning of the rainy season, reproduced, and returned at the end of the breeding period. Juveniles of the year moved to dry fragments along with adults. These risky reproductive migrations through nonforested habitats that expose individuals to dehydration, predation, and other hazards may cause population declines in dry fragments. Indeed, capture rates were significantly lower in dry fragments compared with wet fragments. Declining amphibians would strongly benefit from investments in the conservation and restoration of riparian vegetation and corridors linking breeding and nonbreeding areas.

  7. Microbial infections in a declining wild turkey population in Texas (USA)

    USGS Publications Warehouse

    Rocke, T.E.; Yuill, Thomas M.

    1987-01-01

    A survey was conducted at 5 locations in Texas for avian pathogens that might adversely affect wild turkey (Meleagris gallopavo) productivity and survival. At 1 site, the Rob and Bessie Welder Wildlife Refuge (WWR), turkeys have declined precipitously in recent years. During the winters of 1983-85, 442 wild turkeys were caught with cannon and drop nets, 161 of these on WWR. Blood samples were drawn for serologic evaluation, and cloacal and tracheal swabs were collected for isolation attempts. Salmonella spp. bacteria, Newcastle disease virus (NDV), and avian influenza virus (AIV) were not detected in any samples tested. Serologic tests for antibodies to NDV and AIV also were negative. Many mycoplasma isolates were recovered from turkeys from every location. Characterization of these isolates indicated that several species were present. None were species typically associated with mycoplasmosis in domestic turkeys, such as Mycoplasma gallisepticum (MG), M. meleagridis (MM), or M. synoviae (MS), although antibodies to these pathogens were detected in turkeys at every location sampled. There was no evidence to link any of these disease causing agents to the decline observed in the population of wild turkeys on the WWR.

  8. Ecophysiology meets conservation: understanding the role of disease in amphibian population declines

    PubMed Central

    Blaustein, Andrew R.; Gervasi, Stephanie S.; Johnson, Pieter T. J.; Hoverman, Jason T.; Belden, Lisa K.; Bradley, Paul W.; Xie, Gisselle Y.

    2012-01-01

    Infectious diseases are intimately associated with the dynamics of biodiversity. However, the role that infectious disease plays within ecological communities is complex. The complex effects of infectious disease at the scale of communities and ecosystems are driven by the interaction between host and pathogen. Whether or not a given host–pathogen interaction results in progression from infection to disease is largely dependent on the physiological characteristics of the host within the context of the external environment. Here, we highlight the importance of understanding the outcome of infection and disease in the context of host ecophysiology using amphibians as a model system. Amphibians are ideal for such a discussion because many of their populations are experiencing declines and extinctions, with disease as an important factor implicated in many declines and extinctions. Exposure to pathogens and the host's responses to infection can be influenced by many factors related to physiology such as host life history, immunology, endocrinology, resource acquisition, behaviour and changing climates. In our review, we discuss the relationship between disease and biodiversity. We highlight the dynamics of three amphibian host–pathogen systems that induce different effects on hosts and life stages and illustrate the complexity of amphibian–host–parasite systems. We then review links between environmental stress, endocrine–immune interactions, disease and climate change. PMID:22566676

  9. Playing board games, cognitive decline and dementia: a French population-based cohort study.

    PubMed

    Dartigues, Jean François; Foubert-Samier, Alexandra; Le Goff, Mélanie; Viltard, Mélanie; Amieva, Hélène; Orgogozo, Jean Marc; Barberger-Gateau, Pascale; Helmer, Catherine

    2013-08-29

    To study the relationship between board game playing and risk of subsequent dementia in the Paquid cohort. A prospective population-based study. In the Bordeaux area in South Western France. 3675 non-demented participants at baseline. The risk of dementia during the 20 years of follow-up. Among 3675 non-demented participants at baseline, 32.2% reported regular board game playing. Eight-hundred and forty participants developed dementia during the 20 years of follow-up. The risk of dementia was 15% lower in board game players than in non-players (HR=0.85, 95% CI 0.74 to 0.99; p=0.04) after adjustment on age, gender, education and other confounders. The statistical significance disappeared after supplementary adjustment on baseline mini-mental state examination (MMSE) and depression (HR=0.96, 95% CI 0.82 to 1.12; p=0.61). However, board game players had less decline in their MMSE score during the follow-up of the cohort (β=0.011, p=0.03) and less incident depression than non-players (HR=0.84; 95% CI 0.72 to 0.98; p<0.03). A possible beneficial effect of board game playing on the risk of dementia could be mediated by less cognitive decline and less depression in elderly board game players.

  10. Ecophysiology meets conservation: understanding the role of disease in amphibian population declines.

    PubMed

    Blaustein, Andrew R; Gervasi, Stephanie S; Johnson, Pieter T J; Hoverman, Jason T; Belden, Lisa K; Bradley, Paul W; Xie, Gisselle Y

    2012-06-19

    Infectious diseases are intimately associated with the dynamics of biodiversity. However, the role that infectious disease plays within ecological communities is complex. The complex effects of infectious disease at the scale of communities and ecosystems are driven by the interaction between host and pathogen. Whether or not a given host-pathogen interaction results in progression from infection to disease is largely dependent on the physiological characteristics of the host within the context of the external environment. Here, we highlight the importance of understanding the outcome of infection and disease in the context of host ecophysiology using amphibians as a model system. Amphibians are ideal for such a discussion because many of their populations are experiencing declines and extinctions, with disease as an important factor implicated in many declines and extinctions. Exposure to pathogens and the host's responses to infection can be influenced by many factors related to physiology such as host life history, immunology, endocrinology, resource acquisition, behaviour and changing climates. In our review, we discuss the relationship between disease and biodiversity. We highlight the dynamics of three amphibian host-pathogen systems that induce different effects on hosts and life stages and illustrate the complexity of amphibian-host-parasite systems. We then review links between environmental stress, endocrine-immune interactions, disease and climate change.

  11. Reproduction and microhabitat selection in a sharply declining Northern Bobwhite population

    USGS Publications Warehouse

    Collins, B.M.; Williams, C.K.; Castelli, Paul M.

    2009-01-01

    Northern Bobwhite (Colinus virginianus) populations have been declining throughout their range, but some of the sharpest declines have been documented in the Mid-Atlantic states. We conducted a 2 year (2006-2007) breeding season (1 May-30 Sep) telemetry study in southern New Jersey to collect baseline data on Northern Bobwhite reproductive rates, and nest and brood microhabitat selection. We located 23 Northern Bobwhite nests, of which 21 were usable for survival analyses. Incubation-period nest survival rate was 0.454 ?? 0.010 (95 CI =0.2800.727). Mean clutch size was 14.2 ?? 0.58 (range 10-19, n = 20) and hatching success was 96.1 ?? 2.0 (range 86-100%, n = 10). The estimated probability that an individual that entered the breeding season would initiate incubation of ???1 nest was 0.687 for females and 0.202 for males. Nest microhabitat selection was positively related to visual obstruction and percentage of litter. Brood microhabitat selection was positively related to visual obstruction, vegetation height, and percentage of forbs but negatively related to percentage of cool season grass and litter. Fecundity metrics for Northern Bobwhites in southern New Jersey appear similar to those reported elsewhere in the species' range. Conservation efforts to increase Northern Bobwhite reproductive success in southern New Jersey should focus on increasing the quantity of available breeding habitat. ?? 2009 by the Wilson Ornithological Society.

  12. [A determinant study on population increasing and declining in Chinese feudal society].

    PubMed

    Zhai, Z

    1991-02-01

    The population change in China in feudal times did not follow a continuous curve of growth, instead, it featured steady increases and sharp declines in the population size. The following mechanism caused the growth in population. 1st, the traditional farming system stimulated the reproduction of children to meet the needs for labor power, especially male. 2nd, in the feudal society, land and people were important resources for tax collection and for expansion of territory. And the government often followed a pronatal population policy. 3rd, the cultural tradition and social values of the country have been in favor of large families. Carrying on family lineage and improving family status through many children were important social values. Households with 3 or 4 generations living together were a major form of family structure. These were the factors that contributed to high fertility and population growth. In terms of causes of reduction of population size, it was principally wars and famine. In the feudal history of China, land ownership was always the key issue in the government policy and regulations and in the change of dynasty. Land was the most important and reliable means of production and form of wealth. Polarization of wealth from ownership of land intensified the conflicts between social classes, which caused instability in economics and in the society. War was a manifestation of social instability. In all the dynasties, incessant wars because of struggles within power structures and rebellion from peasants to fight against oppression resulted in massive killings, devastated the economy, and caused drastic reductions in the population numbers. Similar to wars, famine and natural calamities in the imperial dynasties often reversed the population growth trend. In a peasant economy, production was individualized, and the social structure was loose. The minimal means of rural farming families were unable to resist natural disasters. Under severe exploitation

  13. Long-term decline in a red-winged blackbird population: ecological causes and sexual selection consequences

    PubMed Central

    Weatherhead, Patrick J

    2005-01-01

    Habitat loss and large-scale climate phenomena are widely implicated as causing decline in animal populations. I examined how both factors contributed to a precipitous decline in an Ontario red-winged blackbird (Agelaius phoeniceus) population using 16 years of data collected between 1974 and 1995. The decline was manifested as an almost 50% reduction in mean harem size, which reduced the opportunity for sexual selection threefold. Regional hay production, which should affect recruitment into the study population, also declined substantially. Correlation between blackbirds and hay may be coincidental, however, because annual changes in harem size were not associated with annual changes in hay production. This study coincided with an unprecedented positive phase of the North Atlantic Oscillation (NAO). Changes in harem size were correlated with winter NAO index values, suggesting that winter mortality contributed to the population decline. Positive correlation between harem size change and male return rates also supported the winter mortality hypothesis. Continued declines will cause this blackbird population to change from socially polygynous to socially monogamous. Study of red-winged blackbird winter ecology is needed to identify the proximate causes of mortality, whereas breeding studies can explore the consequences of relaxed sexual selection. PMID:16191645

  14. Are orchid bees at risk? First comparative survey suggests declining populations of forest-dependent species.

    PubMed

    Nemésio, A

    2013-05-01

    The two largest Atlantic Forest remnants in the state of Espírito Santo, eastern Brazil, namely 'Reserva Biológica de Sooretama' (REBIO Sooretama) and 'Reserva Natural Vale' (RNV), were surveyed for their orchid-bee faunas. Seventeen scent baits were used to attract orchid-bee males. Three-thousand, two hundred and twenty-five males belonging to 24 species were actively collected with insect nets during 100 hours in March, April and December, 2009. In comparison with a previous study in the same area twelve years before, it is evident that the abundance of all forest-dependent orchid bees analysed declined around 50%, and it was statistically significant (P = 0.022) for Euglossa marianae Nemésio, 2011, the most sensitive to anthropogenic disturbances of all Atlantic Forest orchid bees. On the other hand, the abundance of populations of species tolerant to open or disturbed areas rose. Possible explanations are discussed.

  15. COST ESTIMATION FOR WASTEWATER TREATMENT SYSTEMS FOCUSING ON POPULATION DECLINING IN SANITATION COVE RAGE AREA

    NASA Astrophysics Data System (ADS)

    Kidoura, Shigezane; Takahashi, Masahiro

    In Japan, sanitation coverage is exceeded 70% and sanitary conditions have improved. However in the future, these facilities need to be rebuilt. For that, much money will be needed. On the other hand, prolonged population decrease is predicted in Japan, so it is feared that unsound management caused by the declining of sewerage charge. In this study, costs required for the future were calculated by targeting Asahikawa, Hokkaido Prefecture which is already served by sewerage treatment system. As a result, it was found that maintaining of current sewage treatment system would be cheaper than introduction of novel individual treatment system in Asahikawa. In addition, it was turned out that cost reduction is possible in the case of rebuilding sewage pipe efficiently than maintaining the status quo.

  16. Extensive population decline in the Tasmanian devil predates European settlement and devil facial tumour disease.

    PubMed

    Brüniche-Olsen, Anna; Jones, Menna E; Austin, Jeremy J; Burridge, Christopher P; Holland, Barbara R

    2014-11-01

    The Tasmanian devil (Sarcophilus harrisii) was widespread in Australia during the Late Pleistocene but is now endemic to the island of Tasmania. Low genetic diversity combined with the spread of devil facial tumour disease have raised concerns for the species' long-term survival. Here, we investigate the origin of low genetic diversity by inferring the species' demographic history using temporal sampling with summary statistics, full-likelihood and approximate Bayesian computation methods. Our results show extensive population declines across Tasmania correlating with environmental changes around the last glacial maximum and following unstable climate related to increased 'El Niño-Southern Oscillation' activity. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  17. Population decline in Polish and Czech cities during post-socialism? Looking behind the official statistics.

    PubMed

    Steinführer, Annett; Bierzynski, Adam; Grossmann, Katrin; Haase, Annegret; Kabisch, Sigrun; Klusácek, Petr

    2010-01-01

    The evolving debate on "urban shrinkage" mirrors an increasing interest in demographic phenomena on the part of urban scholars. This paper discusses ambiguous evidence about recent population decline in the large cities of Poland and the Czech Republic, with a particular focus on Łódz and Brno in general and their inner cities more specifically. By applying a mixed-method approach, the paper identifies indications of inner-city repopulation and socio-demographic diversification which are not yet apparent in register or census data. It is argued that there are indications of a silent transformation of traditional residential patterns and neighbourhoods in east central Europe. In the inner cities, this is reflected, amongst other things, by the presence of new households that may be called "transitory urbanites".

  18. Physiological condition of bank voles (Myodes glareolus) during the increase and decline phases of the population cycle.

    PubMed

    Nieminen, Petteri; Huitu, Otso; Henttonen, Heikki; Finnilä, Mikko A J; Voutilainen, Liina; Itämies, Juhani; Kärjä, Vesa; Saarela, Seppo; Halonen, Toivo; Aho, Jari; Mustonen, Anne-Mari

    2015-09-01

    The dynamics of animal populations are greatly influenced by interactions with their natural enemies and food resources. However, quantifying the relative effects of these factors on demographic rates remains a perpetual challenge for animal population ecology. Food scarcity is assumed to limit the growth and to initiate the decline of cyclic herbivore populations, but this has not been verified with physiological health indices. We hypothesized that individuals in declining populations would exhibit signs of malnutrition-induced deterioration of physiological condition. We evaluated the association of body condition with population cycle phase in bank voles (Myodes glareolus) during the increase and decline phases of a population cycle. The bank voles had lower body masses, condition indices and absolute masses of particular organs during the decline. Simultaneously, they had lower femoral masses, mineral contents and densities. Hemoglobin and hematocrit values and several parameters known to respond to food deprivation were unaffected by the population phase. There were no signs of lymphopenia, eosinophilia, granulocytosis or monocytosis. Erythrocyte counts were higher and plasma total protein levels and tissue proportions of essential polyunsaturated fatty acids lower in the population decline. Ectoparasite load was lower and adrenal gland masses or catecholamine concentrations did not suggest higher stress levels. Food availability seems to limit the size of voles during the decline but they can adapt to the prevailing conditions without clear deleterious health effects. This highlights the importance of quantifying individual health state when evaluating the effects of complex trophic interactions on the dynamics of wild animal populations. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. [The decline in the population growth rate--a priority issue in international politics].

    PubMed

    Rhein, E

    1994-08-25

    The Third International UN Conference on Population and Development took place in Cairo in early September 1994 with the participation of 200 governments and 1000 nongovernmental organizations to discuss ways of stabilizing world population at the possible lowest level and how industrialized countries could contribute to this effort. As a consequence of the advances in reproductive medicine the use of contraceptives skyrocketed: in 1994 more than half of men and women were using contraception compared to only 5% in 1950. However, the demographic momentum would still increase world population for another 100 years, even if fertility would drop to 2.2 children per couple (compared to 4 children in 1990). Nevertheless, the present generation could be instrumental in deciding whether the world's population will remain around 8 billion or reach 12 billion between 2050 and 2150. Poor countries can no longer afford an annual growth rate of 2-4% while also trying to improve living standards; this would require an economic growth rate of 6-8%. For the control of population growth both a sustainable environmental policy in the North, with rapid transition to renewable energy and recycling, and a more effective population policy in the South are needed. Family planning (FP) is the precondition of stabilization. The global FP outlays are envisioned to double from the 1994 figure of $5 billion to over $10 billion in the year 2000, with donor contributions to increase from 20% to 40% of the total. The US contribution is to double from $500 million by 2000, while the European Commission decided to boost expenditures for FP from DM 30 million in 1994 to DM 600 million by 2000. Japan is also expending $3 billion during this period. Recent promising developments have emerged: national pronatalist policies have diminished sharply and the pronatalist influence of religions has also declined. Political commitment at the highest level is central to a successful population policy as

  20. Population structure, historical biogeography and demographic history of the alpine toad Scutiger ningshanensis in the Tsinling Mountains of Central China.

    PubMed

    Meng, Hongzhe; Li, Xiaochen; Qiao, Penghai

    2014-01-01

    Population genetic structure, historical biogeography and historical demography of the alpine toad Scutiger ningshanensis were studied using the combined data mtDNA cytochrome b (cyt b) and the mtDNA cytochrome c oxidase subunit I (COI) as the molecular markers. This species has high genetic variation. There was a significant genetic differentiation among most populations. Three lineages were detected. The phylogenetic relationship analyses and the SAMOVA (spatial analysis of molecular variance) results showed significant phylogeographic structure. 82.15% genetic variation occurred among populations whereas differentiation within populations only contributed 17.85% to the total. Mantel test results showed a significant correlation between the pairwise calculated genetic distance and pairwise calculated geographical distance of the populations (regression coefficient  = 0.001286, correlation coefficient  = 0.77051, p (rrand≥robs)  = 0.0185<0.05), indicating the existence of isolation-by-distance pattern of genetic divergence for cyt b + COI sequence, which suggests that the distribution of genetic variation is due to geographical separation rather than natural selection. The population expansion or contraction and genetic differentiation between populations or lineages could be explained by topography and the repetitive uplifts of the Tsinling Mountains and the climatic cycles during the late Pliocene and Pleistocene. S. ningshanensis experienced a rapid population expansion about 40,000 years before present. The current decline in population size was probably caused by anthropogenic disturbance. Current populations of S. ningshanensis are from different refugia though the location of these refugia could not be determined in our study. Topography, climatic changes and repetitive population expansion/contraction together led to the high level of genetic variation in S. ningshanensis. A total of three management units (MUs) was determined, which must be

  1. Population Structure, Historical Biogeography and Demographic History of the Alpine Toad Scutiger ningshanensis in the Tsinling Mountains of Central China

    PubMed Central

    Meng, Hongzhe; Li, Xiaochen; Qiao, Penghai

    2014-01-01

    Population genetic structure, historical biogeography and historical demography of the alpine toad Scutiger ningshanensis were studied using the combined data mtDNA cytochrome b (cyt b) and the mtDNA cytochrome c oxidase subunit I (COI) as the molecular markers. This species has high genetic variation. There was a significant genetic differentiation among most populations. Three lineages were detected. The phylogenetic relationship analyses and the SAMOVA (spatial analysis of molecular variance) results showed significant phylogeographic structure. 82.15% genetic variation occurred among populations whereas differentiation within populations only contributed 17.85% to the total. Mantel test results showed a significant correlation between the pairwise calculated genetic distance and pairwise calculated geographical distance of the populations (regression coefficient  = 0.001286, correlation coefficient  = 0.77051, p (rrand≥robs)  = 0.0185<0.05), indicating the existence of isolation-by-distance pattern of genetic divergence for cyt b + COI sequence, which suggests that the distribution of genetic variation is due to geographical separation rather than natural selection. The population expansion or contraction and genetic differentiation between populations or lineages could be explained by topography and the repetitive uplifts of the Tsinling Mountains and the climatic cycles during the late Pliocene and Pleistocene. S. ningshanensis experienced a rapid population expansion about 40,000 years before present. The current decline in population size was probably caused by anthropogenic disturbance. Current populations of S. ningshanensis are from different refugia though the location of these refugia could not be determined in our study. Topography, climatic changes and repetitive population expansion/contraction together led to the high level of genetic variation in S. ningshanensis. A total of three management units (MUs) was determined, which must be

  2. Comments on Brodie and Post: Climate-driven declines in wolverine populations: Causal connection or spurious correlation?

    Treesearch

    Kevin S. McKelvey; Eric C. Lofroth; Jeffrey P. Copeland; Keith B. Aubry; Audrey J. Magoun

    2010-01-01

    The recent paper by Brodie and Post ("Nonlinear responses of wolverine populations to declining winter snowpack", Popul Ecol 52:279-287, 2010) reports conclusions that are unsupportable, in our opinion, due to both mis-interpretations of current knowledge regarding the wolverine's (Gulo gulo) association with snow, and the uncritical use of harvest data...

  3. Population dynamics of the critically endangered golden lancehead pitviper, Bothrops insularis: stability or decline?

    PubMed

    Guimarães, Murilo; Munguía-Steyer, Roberto; Doherty, Paul F; Martins, Marcio; Sawaya, Ricardo J

    2014-01-01

    Little is known about vital rates of snakes generally because of the difficulty in collecting data. Here we used a robust design mark-recapture model to estimate survival, behavioral effects on capture probability, temporary emigration, abundance and test the hypothesis of population decline in the golden lancehead pitviper, Bothrops insularis, an endemic and critically endangered species from southeastern Brazil. We collected data at irregular intervals over ten occasions from 2002 to 2010. Survival was slightly higher in the wet season than in the dry season. Temporal emigration was high, indicating the importance of accounting for this parameter both in the sampling design and modeling. No behavioral effects were detected on capture probability. We detected an average annual population decrease (λ = 0.93, CI = 0.47-1.38) during the study period, but estimates included high uncertainty, and caution in interpretation is needed. We discuss the potential effects of the illegal removal of individuals and the implications of the vital rates obtained for the future persistence and conservation of this endemic, endangered species.

  4. Evaluating the performance of methods for estimating the abundance of rapidly declining coastal shark populations.

    PubMed

    McCauley, Douglas J; McLean, Kevin A; Bauer, John; Young, Hillary S; Micheli, Fiorenza

    2012-03-01

    Accurately surveying shark populations is critical to monitoring precipitous ongoing declines in shark abundance and interpreting the effects that these reductions are having on ecosystems. To evaluate the effectiveness of existing survey tools, we used field trials and computer simulations to critically examine the operation of four common methods for counting coastal sharks: stationary point counts, belt transects, video surveys, and mark and recapture abundance estimators. Empirical and theoretical results suggest that (1) survey method selection has a strong impact on the estimates of shark density that are produced, (2) standardizations by survey duration are needed to properly interpret and compare survey outputs, (3) increasing survey size does not necessarily increase survey precision, and (4) methods that yield the highest density estimates are not always the most accurate. These findings challenge some of the assumptions traditionally associated with surveying mobile marine animals. Of the methods we trialed, 8 x 50 m belt transects and a 20 m radius point count produced the most accurate estimates of shark density. These findings can help to improve the ways we monitor, manage, and understand the ecology of globally imperiled coastal shark populations.

  5. Unravelling the annual cycle in a migratory animal: breeding-season habitat loss drives population declines of monarch butterflies.

    PubMed

    Flockhart, D T Tyler; Pichancourt, Jean-Baptiste; Norris, D Ryan; Martin, Tara G

    2015-01-01

    Threats to migratory animals can occur at multiple periods of the annual cycle that are separated by thousands of kilometres and span international borders. Populations of the iconic monarch butterfly (Danaus plexippus) of eastern North America have declined over the last 21 years. Three hypotheses have been posed to explain the decline: habitat loss on the overwintering grounds in Mexico, habitat loss on the breeding grounds in the United States and Canada, and extreme weather events. Our objectives were to assess population viability, determine which life stage, season and geographical region are contributing the most to population dynamics and test the three hypotheses that explain the observed population decline. We developed a spatially structured, stochastic and density-dependent periodic projection matrix model that integrates patterns of migratory connectivity and demographic vital rates across the annual cycle. We used perturbation analysis to determine the sensitivity of population abundance to changes in vital rate among life stages, seasons and geographical regions. Next, we compared the singular effects of each threat to the full model where all factors operate concurrently. Finally, we generated predictions to assess the risk of host plant loss as a result of genetically modified crops on current and future monarch butterfly population size and extinction probability. Our year-round population model predicted population declines of 14% and a quasi-extinction probability (<1000 individuals) >5% within a century. Monarch abundance was more than four times more sensitive to perturbations of vital rates on the breeding grounds than on the wintering grounds. Simulations that considered only forest loss or climate change in Mexico predicted higher population sizes compared to milkweed declines on the breeding grounds. Our model predictions also suggest that mitigating the negative effects of genetically modified crops results in higher population size and

  6. Association of Lifetime Intellectual Enrichment with Cognitive Decline in the Older Population

    PubMed Central

    Vemuri, Prashanthi; Lesnick, Timothy G.; Przybelski, Scott A.; Machulda, Mary; Knopman, David S.; Mielke, Michelle M.; Roberts, Rosebud O.; Geda, Yonas E.; Rocca, Walter A.; Petersen, Ronald C.; Jack, Clifford R.

    2014-01-01

    IMPORTANCE Intellectual lifestyle enrichment throughout life is increasingly viewed as a protective strategy against commonly observed cognitive decline in the elderly. OBJECTIVE To investigate the association of lifetime intellectual enrichment with baseline cognitive performance and rate of cognitive decline in a non-demented elderly population and to estimate difference (in years) associated with lifetime intellectual enrichment to the onset of cognitive impairment. DESIGN, SETTING, PARTICIPANTS Prospective analysis of subjects enrolled in the Mayo Clinic Study of Aging (MCSA), a longitudinal population-based study of cognitive aging in Olmsted County, Minnesota. We studied 1995 non-demented (1718 cognitively normal, 277 MCI) participants in MCSA who completed intellectual lifestyle measures at baseline and underwent at least one follow-up visit. MAIN OUTCOMES AND MEASURES We studied the effect of lifetime intellectual enrichment by separating the variables into two non-overlapping principal components: education/occupation-score and mid/late-life cognitive activity measure based on self-report questionnaires. A global cognitive Z-score served as our summary cognition measure. We used linear mixed-effects models to investigate the associations of demographic and intellectual enrichment measures with global cognitive Z-score trajectories. RESULTS Baseline cognitive performance was lower in older subjects and in those with lower education/occupation, lower mid/late-life cognitive activity, apolipoprotein E4 (APOE) genotype, and in men. The interaction between the two intellectual enrichment measures was significant such that the beneficial effect of mid/late-life cognitive activity on baseline cognitive performance was reduced with increasing education/occupation. Only baseline age, mid/late-life cognitive activity, and APOE4 genotype were significantly associated with longitudinal change in cognitive performance from baseline. For APOE4 carriers with high

  7. Mitochondrial DNA Regionalism and Historical Demography in the Extant Populations of Chirocephalus kerkyrensis (Branchiopoda: Anostraca)

    PubMed Central

    Ketmaier, Valerio; Marrone, Federico; Alfonso, Giuseppe; Paulus, Kirsten; Wiemann, Annika; Tiedemann, Ralph; Mura, Graziella

    2012-01-01

    Background Mediterranean temporary water bodies are important reservoirs of biodiversity and host a unique assemblage of diapausing aquatic invertebrates. These environments are currently vanishing because of increasing human pressure. Chirocephalus kerkyrensis is a fairy shrimp typical of temporary water bodies in Mediterranean plain forests and has undergone a substantial decline in number of populations in recent years due to habitat loss. We assessed patterns of genetic connectivity and phylogeographic history in the seven extant populations of the species from Albania, Corfu Is. (Greece), Southern and Central Italy. Methodology/Principal Findings We analyzed sequence variation at two mitochondrial DNA genes (Cytochrome Oxidase I and 16s rRNA) in all the known populations of C. kerkyrensis. We used multiple phylogenetic, phylogeographic and coalescence-based approaches to assess connectivity and historical demography across the whole distribution range of the species. C. kerkyrensis is genetically subdivided into three main mitochondrial lineages; two of them are geographically localized (Corfu Is. and Central Italy) and one encompasses a wide geographic area (Albania and Southern Italy). Most of the detected genetic variation (≈81%) is apportioned among the aforementioned lineages. Conclusions/Significance Multiple analyses of mismatch distributions consistently supported both past demographic and spatial expansions with the former predating the latter; demographic expansions were consistently placed during interglacial warm phases of the Pleistocene while spatial expansions were restricted to cold periods. Coalescence methods revealed a scenario of past isolation with low levels of gene flow in line with what is already known for other co-distributed fairy shrimps and suggest drift as the prevailing force in promoting local divergence. We recommend that these evolutionary trajectories should be taken in proper consideration in any effort aimed at protecting

  8. Mitochondrial DNA regionalism and historical demography in the extant populations of Chirocephalus kerkyrensis (Branchiopoda: Anostraca).

    PubMed

    Ketmaier, Valerio; Marrone, Federico; Alfonso, Giuseppe; Paulus, Kirsten; Wiemann, Annika; Tiedemann, Ralph; Mura, Graziella

    2012-01-01

    Mediterranean temporary water bodies are important reservoirs of biodiversity and host a unique assemblage of diapausing aquatic invertebrates. These environments are currently vanishing because of increasing human pressure. Chirocephalus kerkyrensis is a fairy shrimp typical of temporary water bodies in Mediterranean plain forests and has undergone a substantial decline in number of populations in recent years due to habitat loss. We assessed patterns of genetic connectivity and phylogeographic history in the seven extant populations of the species from Albania, Corfu Is. (Greece), Southern and Central Italy. We analyzed sequence variation at two mitochondrial DNA genes (Cytochrome Oxidase I and 16s rRNA) in all the known populations of C. kerkyrensis. We used multiple phylogenetic, phylogeographic and coalescence-based approaches to assess connectivity and historical demography across the whole distribution range of the species. C. kerkyrensis is genetically subdivided into three main mitochondrial lineages; two of them are geographically localized (Corfu Is. and Central Italy) and one encompasses a wide geographic area (Albania and Southern Italy). Most of the detected genetic variation (≈81%) is apportioned among the aforementioned lineages. Multiple analyses of mismatch distributions consistently supported both past demographic and spatial expansions with the former predating the latter; demographic expansions were consistently placed during interglacial warm phases of the Pleistocene while spatial expansions were restricted to cold periods. Coalescence methods revealed a scenario of past isolation with low levels of gene flow in line with what is already known for other co-distributed fairy shrimps and suggest drift as the prevailing force in promoting local divergence. We recommend that these evolutionary trajectories should be taken in proper consideration in any effort aimed at protecting Mediterranean temporary water bodies.

  9. Anthropometric Studies on the Turkish Population - A Historical Review

    PubMed Central

    Neyzi, Olcay; Saka, Hatice Nurçin; Kurtoğlu, Selim

    2013-01-01

    A historical review of anthropometric studies conducted on Turkish children and adults is presented. In view of observed differences in growth status between children of different societies, the need for local reference standards and the methodology to be used for such studies have been stressed. The importance of local studies in reflecting the state of health and nutrition both in children and adults has also been mentioned. While a number of studies in children cited in this paper are designed to compare the growth of children from different socioeconomic levels, other studies aim to establish local reference data for Turkish children. While the historical studies in adults aim to define racial characteristics, the more recent studies aim to bring out nutritional characteristics with emphasis on increasing frequency of obesity. Conflict of interest:None declared. PMID:23419421

  10. Local and global influences on population declines of coastal waders: Purple Sandpiper Calidris maritima numbers in the Moray Firth, Scotland

    NASA Astrophysics Data System (ADS)

    Summers, Ron W.; Foster, Simon; Swann, Bob; Etheridge, Brian

    2012-05-01

    Declines in numbers by several wader species in Britain have been linked to climate change, but the mechanism for the declines has rarely been explored. Britain lies at the northern end of the East Atlantic Flyway, and supports 1.3 million out of the Flyway's 8.5 million coastal waders (Charadrii) in winter and the Purple Sandpiper is one of the species whose numbers have declined. Here, we examine the dynamics of the decline as observed in the Moray Firth, northeast Scotland, investigating whether the decline was due to poorer apparent survival (return rate) or poorer recruitment of young birds. The maximum number in the Moray Firth declined from 860 in 1987/88 to 236 in 2006/07, with some increase during winters 2007/08 and 2008/09. At the three main high-tide roosts (Balintore, Lossiemouth and Buckie) the maximum combined number declined from 574 to 90. Changes in survival and recruitment (percentage of first-year birds) were examined at these roosts from captured samples, which were ringed and recaptured. There were no significant changes between winters in survival rates, nor were there differences between the survival rates of age groups (first-year and adult) or bill size groups, which represented birds of different sex and breeding origin. Annual survival estimates for the three roosts ranged from 72 to 77%. The percentage of first-year birds varied among roosts and years; the lowest values were during the late 1980s/early 1990s and early 2000s. A free-running population model incorporating varying percentages of first-year birds and constant mortality for each roost provided a plausible explanation for the decline. Although modelled numbers followed the observed pattern, a discrepancy in one year was carried forward in subsequent years, so that the fit with the observed numbers was parallel rather than similar. However, it seems that the decline in numbers was largely due to poorer recruitment. We discuss whether breeding success had declined, whether the

  11. Pathogens, nutritional deficiency, and climate influences on a declining moose population

    USGS Publications Warehouse

    Murray, D.L.; Cox, E.W.; Ballard, W.B.; Whitlaw, H.A.; Lenarz, M.S.; Custer, T.W.; Barnett, T.; Fuller, T.K.

    2006-01-01

    Several potential proximate causes may be implicated in a recent (post-1984) decline in moose (Alces alces andersoni) numbers at their southern range periphery in northwest Minnesota, USA. These causes include deleterious effects of infectious pathogens, some of which are associated with white-tailed deer (Odocoileus virginianus), negative effects of climate change, increased food competition with deer or moose, legal or illegal hunting, and increased predation by gray wolves (Canis lupus) and black bears (Ursus americanus). Long-standing factors that may have contributed to the moose decline include those typically associated with marginal habitat such as nutritional deficiencies. We examined survival and productivity among radiocollared (n = 152) adult female and juvenile moose in northwest Minnesota during 1995–2000, and assessed cause of death and pathology through carcass necropsy of radiocollared and non-radiocollared animals.Aerial moose surveys suggested that hunting was an unlikely source of the numerical decline because the level of harvest was relatively low (i.e., approx. 15% / 2 yr) and the population usually grew in years following a hunt. The majority of moose mortalities (up to 87% of radiocollared moose [n = 76] and up to 65% of non-radiocollared moose [n = 84]) were proximally related to pathology associated with parasites and infectious disease. Liver fluke (Fascioloides magna) infections apparently constituted the greatest single source of mortality and caused significant pathology in the liver, thoracic and peritoneal cavities, pericardial sac, and lungs. Mortality due to meningeal worm (Parelaphostrongylus tenuis) was less prevalent and was manifested through characteristic neurological disease. Several mortalities apparently were associated with unidentified infectious disease, probably acting in close association with malnutrition. Bone-marrow fat was lower for moose dying of natural causes than those dying of anthropogenic factors or

  12. Allegheny woodrat (Neotoma magister) captive propagation to promote recovery of declining populations.

    PubMed

    Smyser, Timothy J; Swihart, Robert K

    2014-01-01

    The Allegheny woodrat (Neotoma magister) is endemic to the eastern United States with local distributions restricted to rocky habitats within deciduous forests. Over the last 40 years, woodrats have declined precipitously due to an array of human-mediated pressures. There is growing interest in the captive propagation of woodrats as a tool to promote in situ conservation, but their solitary social structure, territorial behavior, and low fecundity present challenges for the attainment of levels of ex situ reproduction sufficient to support reintroduction programs. In 2009 we established a captive breeding program with 12 wild-caught individuals (4.8) collected from Indiana and Pennsylvania. Restricting breeding to wild-caught individuals, over 26 months we produced 19 litters comprised of 43 pups (26.17), of which 40 (24.16) survived to weaning. In sum, wild-caught individuals readily habituated to the captive environment and the low fecundity of woodrats was offset by high survival rates for both adults and juveniles. Therefore, when managed appropriately, captive Allegheny woodrat populations should be capable of supporting the release of surplus individuals to augment in situ conservation measures. © 2014 Wiley Periodicals Inc.

  13. Dual-pathogen etiology of avian trichomonosis in a declining band-tailed pigeon population.

    PubMed

    Girard, Yvette A; Rogers, Krysta H; Woods, Leslie W; Chouicha, Nadira; Miller, Woutrina A; Johnson, Christine K

    2014-06-01

    The Pacific Coast band-tailed pigeon (Patagioenas fasciata monilis) is a migratory game bird of North America that is at risk for population decline. Epidemics of avian trichomonosis caused by upper digestive tract infection with Trichomonas spp. protozoa in these and other doves and pigeons of the United States are sporadic, but can involve tens of thousands of birds in a single event. Herein, we analyze the role of trichomonosis in band-tailed pigeon mortality and relate spatial, temporal and demographic patterns of parasite transmission to the genetic background of the infecting organism. Infections were most common in adult birds and prevalence was high in band-tailed pigeons sampled at mortality events (96%) and rehabilitation centers (36%) compared to those that were hunter-killed (11%) or live-caught (4%). During non-epidemic periods, animals were primarily infected with T. gallinae Fe-hydrogenase subtype A2, and were less often infected with either T. gallinae subtype A1 (the British finch epidemic strain), T. stableri n. sp. (a T. vaginalis-like species), or Tritrichomonas blagburni n. sp.-like organisms. Birds sampled during multiple epidemics in California were only infected with T. gallinae subtype A2 and T. stableri. The non-clonal etiology of avian trichomonosis outbreaks in band-tailed pigeons and the risk of spill-over to raptor and passerine species highlights the need for additional studies that clarify the host range and evolutionary relationships between strains of Trichomonas spp. in regions of trichomonosis endemicity.

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

    USGS Publications Warehouse

    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.

  15. A review of possible causes of nutrient enrichment and decline of endangered sucker populations in Upper Klamath Lake, Oregon

    USGS Publications Warehouse

    Bortleson, Gilbert C.; Fretwell, Marvin O.

    1993-01-01

    Ten possible causes for this excessive enrichment in nutrients are described. Three of these hypotheses are suggested for immediate testing because of large-scale changes in nutrient loading that may have occurred as a result of man’s activities. These three hypotheses relate nutrient enrichment to (1) conversion of marshland to agricultural land, (2) agricultural drainage from the basin, and (3) reservoir regulation. Eleven possible hypothetical causes for the decline in sucker populations also are described. The decline in sucker population may be related to excessive nutrient enrichment (eutrophication) of the lake.

  16. Evidence that disease-induced population decline changes genetic structure and alters dispersal patterns in the Tasmanian devil

    PubMed Central

    Lachish, S; Miller, K J; Storfer, A; Goldizen, A W; Jones, M E

    2011-01-01

    Infectious disease has been shown to be a major cause of population declines in wild animals. However, there remains little empirical evidence on the genetic consequences of disease-mediated population declines, or how such perturbations might affect demographic processes such as dispersal. Devil facial tumour disease (DFTD) has resulted in the rapid decline of the Tasmanian devil, Sarcophilus harrisii, and threatens to cause extinction. Using 10 microsatellite DNA markers, we compared genetic diversity and structure before and after DFTD outbreaks in three Tasmanian devil populations to assess the genetic consequences of disease-induced population decline. We also used both genetic and demographic data to investigate dispersal patterns in Tasmanian devils along the east coast of Tasmania. We observed a significant increase in inbreeding (FIS pre/post-disease −0.030/0.012, P<0.05; relatedness pre/post-disease 0.011/0.038, P=0.06) in devil populations after just 2–3 generations of disease arrival, but no detectable change in genetic diversity. Furthermore, although there was no subdivision apparent among pre-disease populations (θ=0.005, 95% confidence interval (CI) −0.003 to 0.017), we found significant genetic differentiation among populations post-disease (θ=0.020, 0.010–0.027), apparently driven by a combination of selection and altered dispersal patterns of females in disease-affected populations. We also show that dispersal is male-biased in devils and that dispersal distances follow a typical leptokurtic distribution. Our results show that disease can result in genetic and demographic changes in host populations over few generations and short time scales. Ongoing management of Tasmanian devils must now attempt to maintain genetic variability in this species through actions designed to reverse the detrimental effects of inbreeding and subdivision in disease-affected populations. PMID:20216571

  17. Evidence that disease-induced population decline changes genetic structure and alters dispersal patterns in the Tasmanian devil.

    PubMed

    Lachish, S; Miller, K J; Storfer, A; Goldizen, A W; Jones, M E

    2011-01-01

    Infectious disease has been shown to be a major cause of population declines in wild animals. However, there remains little empirical evidence on the genetic consequences of disease-mediated population declines, or how such perturbations might affect demographic processes such as dispersal. Devil facial tumour disease (DFTD) has resulted in the rapid decline of the Tasmanian devil, Sarcophilus harrisii, and threatens to cause extinction. Using 10 microsatellite DNA markers, we compared genetic diversity and structure before and after DFTD outbreaks in three Tasmanian devil populations to assess the genetic consequences of disease-induced population decline. We also used both genetic and demographic data to investigate dispersal patterns in Tasmanian devils along the east coast of Tasmania. We observed a significant increase in inbreeding (F(IS) pre/post-disease -0.030/0.012, P<0.05; relatedness pre/post-disease 0.011/0.038, P=0.06) in devil populations after just 2-3 generations of disease arrival, but no detectable change in genetic diversity. Furthermore, although there was no subdivision apparent among pre-disease populations (θ=0.005, 95% confidence interval (CI) -0.003 to 0.017), we found significant genetic differentiation among populations post-disease (θ=0.020, 0.010-0.027), apparently driven by a combination of selection and altered dispersal patterns of females in disease-affected populations. We also show that dispersal is male-biased in devils and that dispersal distances follow a typical leptokurtic distribution. Our results show that disease can result in genetic and demographic changes in host populations over few generations and short time scales. Ongoing management of Tasmanian devils must now attempt to maintain genetic variability in this species through actions designed to reverse the detrimental effects of inbreeding and subdivision in disease-affected populations.

  18. Historical sampling reveals dramatic demographic changes in western gorilla populations

    PubMed Central

    2011-01-01

    Background Today many large mammals live in small, fragmented populations, but it is often unclear whether this subdivision is the result of long-term or recent events. Demographic modeling using genetic data can estimate changes in long-term population sizes while temporal sampling provides a way to compare genetic variation present today with that sampled in the past. In order to better understand the dynamics associated with the divergences of great ape populations, these analytical approaches were applied to western gorillas (Gorilla gorilla) and in particular to the isolated and Critically Endangered Cross River gorilla subspecies (G. g. diehli). Results We used microsatellite genotypes from museum specimens and contemporary samples of Cross River gorillas to infer both the long-term and recent population history. We find that Cross River gorillas diverged from the ancestral western gorilla population ~17,800 years ago (95% HDI: 760, 63,245 years). However, gene flow ceased only ~420 years ago (95% HDI: 200, 16,256 years), followed by a bottleneck beginning ~320 years ago (95% HDI: 200, 2,825 years) that caused a 60-fold decrease in the effective population size of Cross River gorillas. Direct comparison of heterozygosity estimates from museum and contemporary samples suggests a loss of genetic variation over the last 100 years. Conclusions The composite history of western gorillas could plausibly be explained by climatic oscillations inducing environmental changes in western equatorial Africa that would have allowed gorilla populations to expand over time but ultimately isolate the Cross River gorillas, which thereafter exhibited a dramatic population size reduction. The recent decrease in the Cross River population is accordingly most likely attributable to increasing anthropogenic pressure over the last several hundred years. Isolation of diverging populations with prolonged concomitant gene flow, but not secondary admixture, appears to be a typical

  19. Declining Snow Cover Reduces Radiative Cooling from Historic Land Use Change in the Western Great Lakes Region

    NASA Astrophysics Data System (ADS)

    Blakely, B.; Rocha, A. V.; McLachlan, J. S.

    2015-12-01

    The Anthropocene is characterized by rapid changes in both land use and snow cover. The relative importance of these two forces remains unknown but may have important and long-term biophysical effects that are not adequately incorporated into current modeling efforts. Humans have altered the landscape of the Eastern U.S. both historically through deforestation during European settlement and more recently through climatic reductions in snow cover. Here we empirically reconstruct historic albedo in the Eastern U.S. using both modern and historic data. We focus on the Western Great Lakes region (MI, WI, MN, IL, IN), a global hotspot of historic deforestation that spans latitudes where anthropogenic climate modifications have produced important changes in snow cover. We find that vegetation changes have caused an overall increase in regional albedo that is strongest where intensive land use persists (i.e. agriculture) and weakest where forest regrowth has occurred. Changes in snow cover have caused an overall decrease in regional albedo that is about half as strong as increase in albedo due to vegetation change. Although the negative forcings of historic land use change may currently provide a radiative 'discount' on regional warming, these benefits are likely to disappear with time as snow cover decreases and forest regrowth continues.

  20. [Fertility decline in Spain].

    PubMed

    Arango, J

    1987-01-01

    The historical processes of secular fertility decline in Spain and Portugal are not well understood. Very few microdemographic studies of small geographic regions or particular social strata have been done. A contribution by David Reher to the First Spanish-Portuguese-Italian Historical Demography Conference on the fertility decline in the interior province of Cuenca, Spain, uses the own-children method to analyze changes in marital fertility in the 19th and 20th centuries. Reher discovered a slight fertility decline of perhaps 15% which occurred between the end of the 18th century and 1860-75. The fertility decline did not resume until after the Spanish Civil War, and then it was a very gradual and continuous process. When instead of the total female population, women aged 35-39 were studied, unequivocal signs of fertility control appeared. Conscious fertility control thus appears to have begun among older women limiting rather than spacing births. Reher's analysis by social groups demonstrates that fertility declined first and more rapidly in the nonagricultural and urban populations and among the higher income groups. The fertility decline in Cuenca was certainly not identical to that in most of Spain, but may have been fairly typical of a large part of the interior. Another contribution to the Historical Demography Conference, by Anna Cabre and Isabel Pujadas, analyzes fertility trends and cyclical fluctuations in 20th century Cataluna, arguing that they must be placed in historical perspective if recent changes are to be understood and plausible projections made. Their work demonstrates the value of selecting a relatively homogeneous geographic unit for analysis. The contribution of Margarita Delgado to the conference analyzed interregional fertility differences in contemporary Spain. The high legitimate fertility of the south of Spain is accentuated by high nuptiality rates. In central Spain, the combination of high legitimate fertility rates and low

  1. Genetic Diversity of Plasmodium falciparum Populations in Malaria Declining Areas of Sabah, East Malaysia

    PubMed Central

    Mohd Abd Razak, Mohd Ridzuan; Sastu, Umi Rubiah; Norahmad, Nor Azrina; Abdul-Karim, Abass; Muhammad, Amirrudin; Muniandy, Prem Kumar; Jelip, Jenarun; Rundi, Christina; Imwong, Mallika; Mudin, Rose Nani; Abdullah, Noor Rain

    2016-01-01

    .532). The genetic data from the present study highlighted the limited diversity and contrasting genetic pattern of P. falciparum populations in the malaria declining areas of Sabah. PMID:27023787

  2. Genetic Diversity of Plasmodium falciparum Populations in Malaria Declining Areas of Sabah, East Malaysia.

    PubMed

    Mohd Abd Razak, Mohd Ridzuan; Sastu, Umi Rubiah; Norahmad, Nor Azrina; Abdul-Karim, Abass; Muhammad, Amirrudin; Muniandy, Prem Kumar; Jelip, Jenarun; Rundi, Christina; Imwong, Mallika; Mudin, Rose Nani; Abdullah, Noor Rain

    2016-01-01

    .532). The genetic data from the present study highlighted the limited diversity and contrasting genetic pattern of P. falciparum populations in the malaria declining areas of Sabah.

  3. Physical Function Decline and the Risk of Elder Self-neglect in a Community-Dwelling Population

    PubMed Central

    Dong, XinQi; Simon, Melissa; Fulmer, Terry; Mendes de Leon, Carlos F.; Rajan, Bharat; Evans, Denis A.

    2010-01-01

    Purpose: This longitudinal study examines the association between physical function decline and the risk of elder self-neglect in a community-dwelling population. Design and Methods: Of the 5,570 participants in the Chicago Health Aging Project, 1,068 were reported to social services agency for suspected elder self-neglect from 1993 to 2005. The primary predictor was objectively assessed physical function using decline in physical performance testing. Secondary predictors were assessed using the decline in self-reported Katz, Nagi, and Rosow–Breslau scales. Outcome of interest was elder self-neglect. Logistic and linear regression models were used to assess these associations. Results: After adjusting for confounding factors, every 1-point decline in physical performance testing was associated with increased risk of reported elder self-neglect (odds ratio [OR], 1.05, confidence interval [CI], 1.03–1.07, p < .001). Decline in Katz (OR, 1.05, CI, 1.00–1.10, p < .05) and decline in Rosow–Breslau (OR, 1.19, CI, 1.11–1.27, p < .001) were associated with increased risk of reported elder self-neglect. Decline in physical performance testing (standardized parameter estimate [PE]: 0.19, SE: 0.06, p = .002), Katz (PE: 0.65, SE: 0.14, p < .001), Nagi (PE: 0.48, SE: 0.14, p < .001), and Rosow–Breslau (PE: 0.57, SE: 0.21, p = .006) scales were associated with increased risk of greater self-neglect severity. Implications: Decline in physical function was associated with increased risk of reported elder self-neglect and greater self-neglect severity in this community-dwelling population. PMID:20019180

  4. Managing habitat to slow or reverse population declines of the Columbia spotted frog in the Northern Great Basin

    USGS Publications Warehouse

    Pilliod, David S.; Richard D. Scherer,

    2015-01-01

    Evaluating the effectiveness of habitat management actions is critical to adaptive management strategies for conservation of imperiled species. We quantified the response of a Great Basin population of the Columbia spotted frog (Rana luteiventris) to multiple habitat improvement actions aimed to reduce threats and reverse population declines. We used mark-recapture data for 1,394 adult frogs that had been marked by state, federal, and university biologists in 9 ponds representing a single population over a 16-year period from 1997 to 2012. With the use of demographic models, we assessed population-level effects of 1) a grazing exclosure constructed around 6 stock ponds that had been used to water livestock for decades before being fully fenced in 2003, and 2) the construction of 3 new stock ponds in 2003 to provide alternative water sources for livestock and, secondarily, to provide additional frog habitat. These management actions were implemented in response to a decline of more than 80% in population size from 1997 to 2002. We found evidence that excluding cattle from ponds and surrounding riparian habitats resulted in higher levels of frog production (more egg masses), higher adult frog recruitment and survival, and higher population growth rate. We also found that frogs colonized the newly constructed stock ponds within 3 years and frogs began breeding in 2 of them after 5 years. The positive effects of the cattle exclosure and additional production from the new ponds, although notable, did not result in full recovery of the population even 9 years later. This slow recovery may be partly explained by the effects of weather on recruitment rates, particularly the negative effects of harsher winters with late springs and higher fall temperatures. Although our findings point to potential successes of habitat management aimed at slowing or reversing rapidly declining frog populations, our study also suggests that recovering from severe population declines can take

  5. Mortality risk factors show similar trends in modern and historic populations exposed to plague.

    PubMed

    Rubini, Mauro; Gualdi-Russo, Emanuela; Manzon, Vanessa S; Rinaldo, Natascia; Bianucci, Raffaella

    2016-05-31

    Plague has been responsible for two major historic pandemics (6th-8th century CE; 14th-19th century CE) and a modern one. The recent Malagasy plague outbreaks raised new concerns on the deadly potential of the plague-causing bacteria Yersinia pestis. Between September 2014 and April 2015, outbreaks of bubonic and pneumonic plague hit the Malagasy population. Two hundred and sixty-three cases, including 71 deaths, have been reported in 16 different districts with a case fatality rate of 27%. The scope of our study was to ascertain whether the risk factors for health in modern-day populations exposed to plague and in ancient populations that faced the two historic pandemics varied or remained substantially unaltered. The risk of mortality of the Malagasy population with those obtained from the reconstruction of three samples of European populations exposed to the historic pandemics was contrasted. The evidence shows that the risks of death are not uniform across age neither in modern nor in historic populations exposed to plague and shows precise concentrations in specific age groups (children between five and nine years of age and young adults). Although in the post-antibiotic era, the fatality rates have drastically reduced, both modern and historic populations were exposed to the same risk factors that are essentially represented by a low standard of environmental hygiene, poor nutrition, and weak health systems.

  6. Co-infection of Mycobacterium tuberculosis and Mycobacterium leprae in human archaeological samples: a possible explanation for the historical decline of leprosy

    PubMed Central

    Donoghue, Helen D.; Marcsik, Antónia; Matheson, Carney; Vernon, Kim; Nuorala, Emilia; Molto, Joseph E.; Greenblatt, Charles L.; Spigelman, Mark

    2005-01-01

    Both leprosy and tuberculosis were prevalent in Europe during the first millennium but thereafter leprosy declined. It is not known why this occurred, but one suggestion is that cross-immunity protected tuberculosis patients from leprosy. To investigate any relationship between the two diseases, selected archaeological samples, dating from the Roman period to the thirteenth century, were examined for both Mycobacterium leprae and Mycobacterium tuberculosis DNA, using PCR. The work was carried out and verified in geographically separate and independent laboratories. Several specimens with palaeopathological signs of leprosy were found to contain DNA from both pathogens, indicating that these diseases coexisted in the past. We suggest that the immunological changes found in multi-bacillary leprosy, in association with the socio-economic impact on those suffering from the disease, led to increased mortality from tuberculosis and therefore to the historical decline in leprosy. PMID:15734693

  7. Airborne Pesticides as an Unlikely Cause for Population Declines of Alpine Frogs in the Sierra Nevada, California

    EPA Science Inventory

    Airborne pesticides from the Central Valley of California have been implicated as a cause for population declines of several amphibian species, with the strongest evidence for the mountain yellow-legged frog complex (Rana muscosa and R. sierrae) in the Sierra Nevada. We measured...

  8. Physical Function Decline and the Risk of Elder Self-Neglect in a Community-Dwelling Population

    ERIC Educational Resources Information Center

    Dong, XinQi; Simon, Melissa; Fulmer, Terry; de Leon, Carlos F. Mendes; Rajan, Bharat; Evans, Denis A.

    2010-01-01

    Purpose: This longitudinal study examines the association between physical function decline and the risk of elder self-neglect in a community-dwelling population. Design and Methods: Of the 5,570 participants in the Chicago Health Aging Project, 1,068 were reported to social services agency for suspected elder self-neglect from 1993 to 2005. The…

  9. Physical Function Decline and the Risk of Elder Self-Neglect in a Community-Dwelling Population

    ERIC Educational Resources Information Center

    Dong, XinQi; Simon, Melissa; Fulmer, Terry; de Leon, Carlos F. Mendes; Rajan, Bharat; Evans, Denis A.

    2010-01-01

    Purpose: This longitudinal study examines the association between physical function decline and the risk of elder self-neglect in a community-dwelling population. Design and Methods: Of the 5,570 participants in the Chicago Health Aging Project, 1,068 were reported to social services agency for suspected elder self-neglect from 1993 to 2005. The…

  10. Airborne Pesticides as an Unlikely Cause for Population Declines of Alpine Frogs in the Sierra Nevada, California

    EPA Science Inventory

    Airborne pesticides from the Central Valley of California have been implicated as a cause for population declines of several amphibian species, with the strongest evidence for the mountain yellow-legged frog complex (Rana muscosa and R. sierrae) in the Sierra Nevada. We measured...

  11. Falling Back: The Declining Socioeconomic Status of the Mexican Immigrant Population in the U.S., 1980-1990.

    ERIC Educational Resources Information Center

    Rivera-Batiz, Francisco L.

    This report presents data showing that the socioeconomic status of Mexican immigrants in the United States fell sharply behind that of the total native-born population during the 1980s and also declined relative to that of Mexican Americans. Data from the 1980 and 1990 censuses demonstrate that during the 1980s, the earnings and per capita income…

  12. Loss of sagebrush ecosystems and declining bird populations in the Intermountain West: Priority research issues and information needs

    USGS Publications Warehouse

    ,

    2002-01-01

    Sagebrush lands in the Intermountain West are declining rapidly in quality and extent. Consequently, populations of many bird species dependent on these ecosystems also are declining. The greater sage-grouse has been petitioned for listing as a threatened and endangered species, and other species of sagebrush-obligate birds have special conservation status in most states. We identified the primary issues and information needs during a multi-agency workshop, conducted in response to concerns by management agencies related to declining bird population trends in sagebrush habitats. Priority needs were to (1) obtain a better understanding of bird response to habitat and landscape features, (2) develop monitoring designs to sample habitats and bird populations, (3) determine the effects of land use on sagebrush habitats and dependent bird species, and (4) identify linkages between breeding and wintering ranges. This agenda will identify causes and mechanisms of population declines in birds dependent on sagebrush ecosystems and will lead to better management of the ecosystems upon which they depend.

  13. Sudden deaths and colony population decline in Greek honey bee colonies.

    PubMed

    Bacandritsos, N; Granato, A; Budge, G; Papanastasiou, I; Roinioti, E; Caldon, M; Falcaro, C; Gallina, A; Mutinelli, F

    2010-11-01

    During June and July of 2009, sudden deaths, tremulous movements and population declines of adult honey bees were reported by the beekeepers in the region of Peloponnesus (Mt. Mainalo), Greece. A preliminary study was carried out to investigate these unexplained phenomena in this region. In total, 37 bee samples, two brood frames containing honey bee brood of various ages, eight sugar samples and four sugar patties were collected from the affected colonies. The samples were tested for a range of pests, pathogens and pesticides. Symptomatic adult honey bees tested positive for Varroa destructor, Nosema ceranae, Chronic bee paralysis virus (CBPV), Acute paralysis virus (ABPV), Deformed wing virus (DWV), Sacbrood virus (SBV) and Black queen cell virus (BQCV), but negative for Acarapis woodi. American Foulbrood was absent from the brood samples. Chemical analysis revealed that amitraz, thiametoxan, clothianidin and acetamiprid were all absent from symptomatic adult bees, sugar and sugar patty samples. However, some bee samples, were contaminated with imidacloprid in concentrations between 14 ng/g and 39 ng/g tissue. We present: the infection of Greek honey bees by multiple viruses; the presence of N. ceranae in Greek honey bees and the first record of imidacloprid (neonicotonoid) residues in Greek honey bee tissues. The presence of multiple pathogens and pesticides made it difficult to associate a single specific cause to the depopulation phenomena observed in Greece, although we believe that viruses and N. ceranae synergistically played the most important role. A follow-up in-depth survey across all Greek regions is required to provide context to these preliminary findings. Copyright © 2010 Elsevier Inc. All rights reserved.

  14. Dramatic declines in neotropical salamander populations are an important part of the global amphibian crisis

    PubMed Central

    Rovito, Sean M.; Parra-Olea, Gabriela; Vásquez-Almazán, Carlos R.; Papenfuss, Theodore J.; Wake, David B.

    2009-01-01

    We document major declines of many species of salamanders at several sites in Central America and Mexico, with emphasis on the San Marcos region of Guatemala, one of the best studied and most diverse salamander communities in the Neotropics. Profound declines of several formerly abundant species, including 2 apparent extinctions, are revealed. Terrestrial microhabitat specialists at mid- to high elevations have declined more than microhabitat generalists. These terrestrial microhabitat specialists have largely disappeared from multiple sites in western Guatemala, including in well-protected areas, suggesting that the phenomenon cannot be explained solely by localized habitat destruction. Major declines in southern Mexican plethodontid salamanders occurred in the late 1970s to early 1980s, concurrent with or preceding many reported frog declines. The species in decline comprise several major evolutionary lineages of tropical salamanders, underscoring that significant portions of the phylogenetic diversity of Neotropical salamanders are at risk. Our results highlight the urgent need to document and understand Neotropical salamander declines as part of the larger effort to conserve global amphibian diversity. PMID:19204286

  15. Lead ingestion as a potential contributing factor to the decline in vulture populations in southern Africa.

    PubMed

    Naidoo, V; Wolter, K; Botha, C J

    2017-01-01

    Vulture populations in southern Africa have been on the decline for years, which unlike the Asian vulture crisis, has no one specific cause. Reasons attributable are deliberate and secondary poisonings, drowning, power line injuries, electrocutions, traditional medicine ("muti" trade) and calcium deficiencies. However, lead toxicity as a potential causal factor is hardly mentioned. The potential for lead toxicity needs to be considered as substantial game hunting occurs in the region with little regulatory control on bullet types. In this study, we determined the whole blood lead concentrations of captive and wild vulture populations in South Africa and Namibia (n=185). Results were compared to previous published ranges indicative of background exposure (<10μg/dL), non-toxic point exposure based upon the range established from captive birds and subclinical exposure. In general, whole blood lead concentrations were higher for wild African White-backed vultures (Gyps africanus)(AWBV) than Cape vultures (G. coprotheres)(CGV) at 15.54±12.63μg/dL vs 12.53±8.88μg/dL (non-significantly different), while in the Bearded vultures (Gypaetus barbatus) no indication of exposure was evident. Very similar exposures resulted irrespective of the birds being in captivity or under wild, free-roaming conditions. A proportion of wild birds did, however, appear to be exposed to another source of lead than purely environmental (±12% and 30.6% for AWBV and CGV respectively). One bird, which had a whole blood concentration of 100μg/dL, died soon after capture. To find the relationship between whole blood lead concentration and likely exposure factors, birds were compared by their rural/urban location, vicinity to mines and surrounding soil lead concentrations. With no relationship being present for the latter factors, we believe that this is evidence that the portion of southern African vultures being exposed to unknown source of lead, which we suggest arises from leaded ammunition

  16. Winter body condition of moose (Alces alces) in a declining population in northeastern Minnesota.

    PubMed

    DelGiudice, Glenn D; Sampson, Barry A; Lenarz, Mark S; Schrage, Michael W; Edwards, Andrew J

    2011-01-01

    Assessments of the condition of moose (Alces alces) may be particularly informative to understanding the dynamics of populations and other influential factors. During February-March 2003 to 2005, we assessed the nutritional condition of 79 moose (39 females, 40 males) in northeastern Minnesota by body condition scoring (BCS(F), scale of 0-10); 67 of these by were assessed by ultrasonographic measurements of rump fat (Maxfat), which was used to estimate ingesta-free body fat (IFBF) in all but two of the females. Scores of the BCS(F) were related (r(2)=0.34, P<0.0001) to Maxfat. Body condition scores were not affected by sex × capture-year, capture-year, or age-at-capture, but the mean body condition score of males (6.5 ± 0.2 [SE], n=40) was less (P ≤ 0.009) than that of females (7.4 ± 0.2, n=39). Overall, Maxfat ranged from 0.0 to 4.6 and 0.3 to 2.8 cm in females and males, respectively, and was unaffected by age-at-capture. There was a sex×capture-year effect (P=0.021) on Maxfat; mean values were stable for males during the winters of 2003 to 2005 but in females were lowest during 2003, consistent with the lowest pregnancy rates and lowest winter and spring survival compared to 2004 and 2005. Based on estimates of percent IFBF, late winter-early spring survival in 2003 of at least 11% of the collared animals assessed by Maxfat, 21% of the adult females, specifically, may have been seriously challenged directly by poor condition. Data from this study provide reference values and assessments of body condition of moose that will be an essential component of the additional, comprehensive research needed to better understand the influence of extrinsic and intrinsic factors on the performance of this viable, but declining, population. For future research, we will concentrate on developing a more-reliable BCS which would allow IFBF estimation once rump fat is depleted.

  17. Declines in moose population density at Isle Royle National Park, MI, USA and accompanied changes in landscape patterns

    USGS Publications Warehouse

    De Jager, N. R.; Pastor, J.

    2009-01-01

    Ungulate herbivores create patterns of forage availability, plant species composition, and soil fertility as they range across large landscapes and consume large quantities of plant material. Over time, herbivore populations fluctuate, producing great potential for spatio-temporal landscape dynamics. In this study, we extend the spatial and temporal extent of a long-term investigation of the relationship of landscape patterns to moose foraging behavior at Isle Royale National Park, MI. We examined how patterns of browse availability and consumption, plant basal area, and soil fertility changed during a recent decline in the moose population. We used geostatistics to examine changes in the nature of spatial patterns in two valleys over 18 years and across short-range and long-range distance scales. Landscape patterns of available and consumed browse changed from either repeated patches or randomly distributed patches in 1988-1992 to random point distributions by 2007 after a recent record high peak followed by a rapid decline in the moose population. Patterns of available and consumed browse became decoupled during the moose population low, which is in contrast to coupled patterns during the earlier high moose population. Distributions of plant basal area and soil nitrogen availability also switched from repeated patches to randomly distributed patches in one valley and to random point distributions in the other valley. Rapid declines in moose population density may release vegetation and soil fertility from browsing pressure and in turn create random landscape patterns. ?? Springer Science+Business Media B.V. 2009.

  18. Decline in Endangered Species as an Indication of Anthropic Pressures: The Case of European Mink Mustela lutreola Western Population

    NASA Astrophysics Data System (ADS)

    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.

  19. The influence of historical climate on the population dynamics of three dominant sagebrush steppe plants.

    USDA-ARS?s Scientific Manuscript database

    Climate change could alter the population growth of dominant species, leading to profound effects on community structure and ecosystem dynamics. Understanding the links between historical variation in climate and population vital rates (survival, growth, recruitment) is one way to predict the impact...

  20. Natural and sexual selection in a monogamous historical human population.

    PubMed

    Courtiol, Alexandre; Pettay, Jenni E; Jokela, Markus; Rotkirch, Anna; Lummaa, Virpi

    2012-05-22

    Whether and how human populations exposed to the agricultural revolution are still affected by Darwinian selection remains controversial among social scientists, biologists, and the general public. Although methods of studying selection in natural populations are well established, our understanding of selection in humans has been limited by the availability of suitable datasets. Here, we present a study comparing the maximum strengths of natural and sexual selection in humans that includes the effects of sex and wealth on different episodes of selection. Our dataset was compiled from church records of preindustrial Finnish populations characterized by socially imposed monogamy, and it contains a complete distribution of survival, mating, and reproductive success for 5,923 individuals born 1760-1849. Individual differences in early survival and fertility (natural selection) were responsible for most variation in fitness, even among wealthier individuals. Variance in mating success explained most of the higher variance in reproductive success in males compared with females, but mating success also influenced reproductive success in females, allowing for sexual selection to operate in both sexes. The detected opportunity for selection is in line with measurements for other species but higher than most previous reports for human samples. This disparity results from biological, demographic, economic, and social differences across populations as well as from failures by most previous studies to account for variation in fitness introduced by nonreproductive individuals. Our results emphasize that the demographic, cultural, and technological changes of the last 10,000 y did not preclude the potential for natural and sexual selection in our species.

  1. Natural and sexual selection in a monogamous historical human population

    PubMed Central

    Courtiol, Alexandre; Pettay, Jenni E.; Jokela, Markus; Rotkirch, Anna; Lummaa, Virpi

    2012-01-01

    Whether and how human populations exposed to the agricultural revolution are still affected by Darwinian selection remains controversial among social scientists, biologists, and the general public. Although methods of studying selection in natural populations are well established, our understanding of selection in humans has been limited by the availability of suitable datasets. Here, we present a study comparing the maximum strengths of natural and sexual selection in humans that includes the effects of sex and wealth on different episodes of selection. Our dataset was compiled from church records of preindustrial Finnish populations characterized by socially imposed monogamy, and it contains a complete distribution of survival, mating, and reproductive success for 5,923 individuals born 1760–1849. Individual differences in early survival and fertility (natural selection) were responsible for most variation in fitness, even among wealthier individuals. Variance in mating success explained most of the higher variance in reproductive success in males compared with females, but mating success also influenced reproductive success in females, allowing for sexual selection to operate in both sexes. The detected opportunity for selection is in line with measurements for other species but higher than most previous reports for human samples. This disparity results from biological, demographic, economic, and social differences across populations as well as from failures by most previous studies to account for variation in fitness introduced by nonreproductive individuals. Our results emphasize that the demographic, cultural, and technological changes of the last 10,000 y did not preclude the potential for natural and sexual selection in our species. PMID:22547810

  2. Ancient DNA reveals genetic stability despite demographic decline: 3,000 years of population history in the endemic Hawaiian petrel.

    PubMed

    Welch, Andreanna J; Wiley, Anne E; James, Helen F; Ostrom, Peggy H; Stafford, Thomas W; Fleischer, Robert C

    2012-12-01

    In the Hawaiian Islands, human colonization, which began approximately 1,200 to 800 years ago, marks the beginning of a period in which nearly 75% of the endemic avifauna became extinct and the population size and range of many additional species declined. It remains unclear why some species persisted whereas others did not. The endemic Hawaiian petrel (Pterodroma sandwichensis) has escaped extinction, but colonies on two islands have been extirpated and populations on remaining islands have contracted. We obtained mitochondrial DNA sequences from 100 subfossil bones, 28 museum specimens, and 289 modern samples to investigate patterns of gene flow and temporal changes in the genetic diversity of this endangered species over the last 3,000 years, as Polynesians and then Europeans colonized the Hawaiian Islands. Genetic differentiation was found to be high between both modern and ancient petrel populations. However, gene flow was substantial between the extirpated colonies on Oahu and Molokai and modern birds from the island of Lanai. No significant reductions in genetic diversity occurred over this period, despite fears in the mid-1900s that this species may have been extinct. Simulations show that even a decline to a stable effective population size of 100 individuals would result in the loss of only 5% of the expected heterozygosity. Simulations also show that high levels of genetic diversity may be retained due to the long generation time of this species. Such decoupling between population size and genetic diversity in long-lived species can have important conservation implications. It appears that a pattern of dispersal from declining colonies, in addition to long generation time, may have allowed the Hawaiian petrel to escape a severe genetic bottleneck, and the associated extinction vortex, and persist despite a large population decline after human colonization.

  3. Improved Analysis of Long-Term Monitoring Data Demonstrates Marked Regional Declines of Bat Populations in the Eastern United States.

    PubMed

    Ingersoll, Thomas E; Sewall, Brent J; Amelon, Sybill K

    2013-01-01

    Bats are diverse and ecologically important, but are also subject to a suite of severe threats. Evidence for localized bat mortality from these threats is well-documented in some cases, but long-term changes in regional populations of bats remain poorly understood. Bat hibernation surveys provide an opportunity to improve understanding, but analysis is complicated by bats' cryptic nature, non-conformity of count data to assumptions of traditional statistical methods, and observation heterogeneities such as variation in survey timing. We used generalized additive mixed models (GAMMs) to account for these complicating factors and to evaluate long-term, regional population trajectories of bats. We focused on four hibernating bat species - little brown myotis (Myotis lucifugus), tri-colored bat (Perimyotis subflavus), Indiana myotis (M. sodalis), and northern myotis (M. septentrionalis) - in a four-state region of the eastern United States during 1999-2011. Our results, from counts of nearly 1.2 million bats, suggest that cumulative declines in regional relative abundance by 2011 from peak levels were 71% (with 95% confidence interval of ±11%) in M. lucifugus, 34% (±38%) in P. subflavus, 30% (±26%) in M. sodalis, and 31% (±18%) in M. septentrionalis. The M. lucifugus population fluctuated until 2004 before persistently declining, and the populations of the other three species declined persistently throughout the study period. Population trajectories suggest declines likely resulted from the combined effect of multiple threats, and indicate a need for enhanced conservation efforts. They provide strong support for a change in the IUCN Red List conservation status in M. lucifugus from Least Concern to Endangered within the study area, and are suggestive of a need to change the conservation status of the other species. Our modeling approach provided estimates of uncertainty, accommodated non-linearities, and controlled for observation heterogeneities, and thus has wide

  4. Improved Analysis of Long-Term Monitoring Data Demonstrates Marked Regional Declines of Bat Populations in the Eastern United States

    PubMed Central

    Amelon, Sybill K.

    2013-01-01

    Bats are diverse and ecologically important, but are also subject to a suite of severe threats. Evidence for localized bat mortality from these threats is well-documented in some cases, but long-term changes in regional populations of bats remain poorly understood. Bat hibernation surveys provide an opportunity to improve understanding, but analysis is complicated by bats' cryptic nature, non-conformity of count data to assumptions of traditional statistical methods, and observation heterogeneities such as variation in survey timing. We used generalized additive mixed models (GAMMs) to account for these complicating factors and to evaluate long-term, regional population trajectories of bats. We focused on four hibernating bat species – little brown myotis (Myotis lucifugus), tri-colored bat (Perimyotis subflavus), Indiana myotis (M. sodalis), and northern myotis (M. septentrionalis) – in a four-state region of the eastern United States during 1999–2011. Our results, from counts of nearly 1.2 million bats, suggest that cumulative declines in regional relative abundance by 2011 from peak levels were 71% (with 95% confidence interval of ±11%) in M. lucifugus, 34% (±38%) in P. subflavus, 30% (±26%) in M. sodalis, and 31% (±18%) in M. septentrionalis. The M. lucifugus population fluctuated until 2004 before persistently declining, and the populations of the other three species declined persistently throughout the study period. Population trajectories suggest declines likely resulted from the combined effect of multiple threats, and indicate a need for enhanced conservation efforts. They provide strong support for a change in the IUCN Red List conservation status in M. lucifugus from Least Concern to Endangered within the study area, and are suggestive of a need to change the conservation status of the other species. Our modeling approach provided estimates of uncertainty, accommodated non-linearities, and controlled for observation heterogeneities, and thus

  5. Who and what is a "population"? Historical debates, current controversies, and implications for understanding "population health" and rectifying health inequities.

    PubMed

    Krieger, Nancy

    2012-12-01

    The idea of "population" is core to the population sciences but is rarely defined except in statistical terms. Yet who and what defines and makes a population has everything to do with whether population means are meaningful or meaningless, with profound implications for work on population health and health inequities. In this article, I review the current conventional definitions of, and historical debates over, the meaning(s) of "population," trace back the contemporary emphasis on populations as statistical rather than substantive entities to Adolphe Quetelet's powerful astronomical metaphor, conceived in the 1830s, of l'homme moyen (the average man), and argue for an alternative definition of populations as relational beings. As informed by the ecosocial theory of disease distribution, I then analyze several case examples to explore the utility of critical population-informed thinking for research, knowledge, and policy involving population health and health inequities. Four propositions emerge: (1) the meaningfulness of means depends on how meaningfully the populations are defined in relation to the inherent intrinsic and extrinsic dynamic generative relationships by which they are constituted; (2) structured chance drives population distributions of health and entails conceptualizing health and disease, including biomarkers, as embodied phenotype and health inequities as historically contingent; (3) persons included in population health research are study participants, and the casual equation of this term with "study population" should be avoided; and (4) the conventional cleavage of "internal validity" and "generalizability" is misleading, since a meaningful choice of study participants must be in relation to the range of exposures experienced (or not) in the real-world societies, that is, meaningful populations, of which they are a part. To improve conceptual clarity, causal inference, and action to promote health equity, population sciences need to expand

  6. Decline in a population of spectacled eiders nesting on the Yukon-Kuskokwim Delta, Alaska

    USGS Publications Warehouse

    Ely, Craig; Dau, Christian; Babcock, Christopher

    1994-01-01

    The number of spectacled eiders nesting on two study areas near the Kashunuk River, on the central Yukon-Kuskokwim (Y-K) Delta, Alaska, declined by over 75% in the last 20 years. Nesting densities have remained low, but have not significantly declined since 1985. There has been no decrease in the reproductive effort of individual females as indicated by average clutch sizes. There has been a significant decline in the proportion of nests located on islands on one of the two study areas. Nesting success declined significantly during the 1970's. Success was not monitored in recent years, but has likely been low, based on the poor nesting success and declining numbers of cackling Canada geese and black brant nesting on the area. Nest predation by arctic foxes severely limited the productivity of cackling Canada geese, and foxes were likely the major predators of eider nests. Persistent high predation rates may lead to local extirpation in highly philopatric species such as eiders.

  7. Declining Fertility and the Use of Cesarean Delivery: Evidence from a Population-Based Study in Taiwan

    PubMed Central

    Ma, Ke-Zong M; Norton, Edward C; Lee, Shoou-Yih D

    2010-01-01

    Objective To test the hypothesis that declining fertility would affect the number of cesarean sections (c-sections) on maternal demand, but not medically indicated c-sections. Data Sources The 1996–2004 National Health Insurance Research Database in Taiwan for all singleton deliveries. Study Design Retrospective population-based, longitudinal study. Estimation was performed using multinomial probit models. Principal Findings Results revealed that declining fertility had a significant positive effect on the probability of having a c-section on maternal request but not medically indicated c-section. Conclusions Our findings offer a precautionary note to countries experiencing a fertility decline. Policies to contain the rise of c-sections should understand the role of women's preferences, especially regarding cesarean deliveries on maternal request. PMID:20545781

  8. Infectious disease and worldwide declines of amphibian populations, with comments on emerging diseases in coral reef organisms and in humans.

    PubMed Central

    Carey, C

    2000-01-01

    Many populations of amphibians are declining on all six continents on which they occur. Some causes of amphibian declines, such as habitat destruction, direct application of xenobiotics, and introduction of predators or competitors, are clearly attributable to human activities. Infectious disease appears to be the direct cause of mass amphibian die-offs in relatively undisturbed areas of the world where anthropomorphic environmental disruption is minimal. In these cases, it is not yet clear whether these epizootics result from the natural evolution of new pathogens or from environmental changes that promote the emergence of pathogenic forms and/or that weaken the immune defenses of amphibians. Because some aspects of pathogen-related amphibian mass mortalities are similar to outbreaks of new diseases in humans and coral reef organisms, amphibian declines may be part of a much larger pattern than previously appreciated. PMID:10698730

  9. Infectious disease and worldwide declines of amphibian populations, with comments on emerging diseases in coral reef organisms and in humans.

    PubMed

    Carey, C

    2000-03-01

    Many populations of amphibians are declining on all six continents on which they occur. Some causes of amphibian declines, such as habitat destruction, direct application of xenobiotics, and introduction of predators or competitors, are clearly attributable to human activities. Infectious disease appears to be the direct cause of mass amphibian die-offs in relatively undisturbed areas of the world where anthropomorphic environmental disruption is minimal. In these cases, it is not yet clear whether these epizootics result from the natural evolution of new pathogens or from environmental changes that promote the emergence of pathogenic forms and/or that weaken the immune defenses of amphibians. Because some aspects of pathogen-related amphibian mass mortalities are similar to outbreaks of new diseases in humans and coral reef organisms, amphibian declines may be part of a much larger pattern than previously appreciated.

  10. Long-Term Declining Trends in Historical Wind Measurements at the Blue Hill Meteorological Observatory, 1885-2013

    NASA Astrophysics Data System (ADS)

    Azorin-Molina, C.; Iacono, M. J.

    2014-12-01

    The Blue Hill Meteorological Observatory, located on the 635-foot summit of Great Blue Hill ten miles south of Boston, Massachusetts, has been the site of continuous monitoring of the local weather and climate since its founding in 1885. The meticulous, extensive and high-quality climate record maintained at this location has included the measurement of wind among many other parameters since its earliest days, and this provides a unique opportunity to examine wind speed trends at this site over nearly 130 years. Although multiple wind sensors have been in use during this time and the height of the anemometers was raised in 1908, the wind records have been made as consistent as possible through careful analysis of these changes and the application of adjustments to ensure consistency. The 30-year mean wind speed at this location has decreased from 6.8 m s-1 in the middle 20th century to its present value of 6.0 m s-1 with an increase in the rate of the decline beginning around 1980. The wind speed time series shows a significant (p < 0.05) downward trend over the entire period from 1885-2013 (-0.085 m s-1 decade-1) that is stronger and also significant for the sub-periods from 1961-2013 (-0.266 m s-1 decade-1) and 1979-2008 (-0.342 m s-1 decade-1). This declining trend persists in all seasons and has significant implications for the efficiency of wind power generation in the area, if it reflects a regional change in the near-surface wind regime. The wind instruments in use since the 19th century will be described, and the official long-term record will be compared with measurements from other wind sensors at the Observatory and surrounding locations. In addition, initial investigations of the possible causes of the wind speed decline will be presented in the context of global stilling (i.e. the theory of a widespread decline in measured near-surface wind speed), including an analysis of the wind speed change as a function of wind direction.

  11. Coherent population trapping: its physics and historical roots

    NASA Astrophysics Data System (ADS)

    Shalagin, A. M.

    2017-01-01

    There presented basic information on coherent population trapping (CPT) and related phenomenon of electromagnetically induced transparence, `dark' and `bright' (anomalous absorption) states is presented. Spectrum transformation is considered in probe field spectroscopy for Λ-scheme in various settings. The close relation is revealed between the effect of CPT in the manifold of magnetic sublevels and the phenomenon of optical pumping (optical orientation and optical alignment). CPT is shown to be generalized to the case of several transitions with a common upper level and with the corresponding number of light fields each being in quasiresonance with its `own' transition.

  12. Profound Differences in Virus Population Genetics Correspond to Protection from CD4 Decline Resulting from Feline Lentivirus Coinfection

    PubMed Central

    Padhi, Abinash; Ross, Howard; Terwee, Julie; VandeWoude, Sue; Poss, Mary

    2010-01-01

    CD4 decline is a hallmark of disease onset in individuals infected with Feline Immunodeficiency Virus (FIV) or Human Immunodeficiency Virus type 1 (HIV-1). Cats that are infected with a poorly replicating, apathogenic FIV (PLV) prior to exposure to a virulent FIV strain (FIVC) maintain CD4 numbers by mechanisms that are not correlated with a measurable adaptive immune response or reduction in circulating viral load. We employed population genetic approaches based on the 3′ portion of the viral genome to estimate the population structure of FIVC from single and dual infected cats. In dual infected cats, FIVC effective population size was decreased during the initial viral expansion phase, and after three weeks of infection, the population declined sharply. The FIVC population recovered to pre-bottleneck levels approximately seven weeks post-FIVC infection. However, the population emerging from the bottleneck in dual infected cats was distinct based on estimates of temporal population structure and substitution profiles. The transition to transversion rate ratio (κ) increased from early to late phases in dual infected cats due primarily to a decrease in transversions whereas in single infected cats, κ declined over time. Although one clone with extensive G to A substitutions, indicative of host cytidine deaminase editing, was recovered from a dual infected cat during the bottleneck, the post bottleneck population had an overall reduction in G to A substitutions. These data are consistent with a model of PLV-induced host restriction, putatively involving host DNA editing, that alters the dynamics of FIVC throughout the course of infection leading to disease attenuation. PMID:21994636

  13. The population decline of Gyps vultures in India and Nepal has slowed since veterinary use of diclofenac was banned.

    PubMed

    Prakash, Vibhu; Bishwakarma, Mohan Chandra; Chaudhary, Anand; Cuthbert, Richard; Dave, Ruchi; Kulkarni, Mandar; Kumar, Sashi; Paudel, Khadananda; Ranade, Sachin; Shringarpure, Rohan; Green, Rhys E

    2012-01-01

    Populations of oriental white-backed vulture (Gyps bengalensis), long-billed vulture (Gyps indicus) and slender-billed vulture (Gyps tenuirostris) crashed during the mid-1990s throughout the Indian subcontinent. Surveys in India, initially conducted in 1991-1993 and repeated in 2000, 2002, 2003 and 2007, revealed that the population of Gyps bengalensis had fallen by 2007 to 0.1% of its numbers in the early 1990s, with the population of Gyps indicus and G. tenuirostris combined having fallen to 3.2% of its earlier level. A survey of G. bengalensis in western Nepal indicated that the size of the population in 2009 was 25% of that in 2002. In this paper, repeat surveys conducted in 2011 were analysed to estimate recent population trends. Populations of all three species of vulture remained at a low level, but the decline had slowed and may even have reversed for G. bengalensis, both in India and Nepal. However, estimates of the most recent population trends are imprecise, so it is possible that declines may be continuing, though at a significantly slower rate. The degree to which the decline of G. bengalensis in India has slowed is consistent with the expected effects on population trend of a measured change in the level of contamination of ungulate carcasses with the drug diclofenac, which is toxic to vultures, following a ban on its veterinary use in 2006. The most recent available information indicates that the elimination of diclofenac from the vultures' food supply is incomplete, so further efforts are required to fully implement the ban.

  14. The Population Decline of Gyps Vultures in India and Nepal Has Slowed since Veterinary Use of Diclofenac was Banned

    PubMed Central

    Prakash, Vibhu; Bishwakarma, Mohan Chandra; Chaudhary, Anand; Cuthbert, Richard; Dave, Ruchi; Kulkarni, Mandar; Kumar, Sashi; Paudel, Khadananda; Ranade, Sachin; Shringarpure, Rohan; Green, Rhys E.

    2012-01-01

    Populations of oriental white-backed vulture (Gyps bengalensis), long-billed vulture (Gyps indicus) and slender-billed vulture (Gyps tenuirostris) crashed during the mid-1990s throughout the Indian subcontinent. Surveys in India, initially conducted in 1991–1993 and repeated in 2000, 2002, 2003 and 2007, revealed that the population of Gyps bengalensis had fallen by 2007 to 0.1% of its numbers in the early 1990s, with the population of Gyps indicus and G. tenuirostris combined having fallen to 3.2% of its earlier level. A survey of G. bengalensis in western Nepal indicated that the size of the population in 2009 was 25% of that in 2002. In this paper, repeat surveys conducted in 2011 were analysed to estimate recent population trends. Populations of all three species of vulture remained at a low level, but the decline had slowed and may even have reversed for G. bengalensis, both in India and Nepal. However, estimates of the most recent population trends are imprecise, so it is possible that declines may be continuing, though at a significantly slower rate. The degree to which the decline of G. bengalensis in India has slowed is consistent with the expected effects on population trend of a measured change in the level of contamination of ungulate carcasses with the drug diclofenac, which is toxic to vultures, following a ban on its veterinary use in 2006. The most recent available information indicates that the elimination of diclofenac from the vultures’ food supply is incomplete, so further efforts are required to fully implement the ban. PMID:23145090

  15. Linking temporal changes in the demographic structure and individual growth to the decline in the population of a tropical fish

    NASA Astrophysics Data System (ADS)

    Sirot, Charlotte; Darnaude, Audrey M.; Guilhaumon, François; Ramos-Miranda, Julia; Flores-Hernandez, Domingo; Panfili, Jacques

    2015-11-01

    The exceptional biodiversity and productivity of tropical coastal lagoons can only be preserved by identifying the causes for the decline in the populations living in these vulnerable ecosystems. The Terminos lagoon in Mexico provided an opportunity for studying this issue as some of its fish populations, in particular the Silver Perch (Bairdiella chrysoura), have declined significantly since the 1980s. Fish sampling campaigns carried out over the whole lagoon area in 1979-81 and again in 2006-2011 revealed the mechanisms which may have been responsible for this decline. Based on biometrical data for 295 juveniles and adults from the two periods and on somatic growth derived from 173 otoliths, a study of the temporal changes in the demographic structure and life history traits (individual growth and body condition) made it possible to distinguish the causes of the decline in the B. chrysoura population. Growth models for the lagoon in 1980-1981 and 2006-2011 showed no significant change in the growth parameters of the population over the last 30 years with a logistic model giving an accurate estimate (R2 = 0.66) of the size-at-age for both periods. The decline in the B. chrysoura population could not be explained by an overall decrease in individual size and condition in the lagoon, the average standard length (SL) and Fulton index (FI) having increased slightly since 1980-1981 (4.6 mm and 0.02 for juveniles and 5.42 mm and 0.07 for adults). However, the size structure of the population in the lagoon has changed, with a significant shift in the size distribution of juveniles with a marked reduction in the proportion of juveniles ≤ 60 mm in the captures (90.9% fewer than in 1980-1981). As the otolith growth rate of fish during the first 4 months also decreased significantly between the two sampling periods (-15%), it is suggested that the main reason for the decline in the abundance and biomass of B. chrysoura within this system may be that its habitats are less

  16. Historical and contemporary DNA indicate fisher decline and isolation occurred prior to the European settlement of California

    Treesearch

    Jody M. Tucker; Michael K. Schwartz; Richard L. Truex; Kristine L. Pilgrim; Fred W. Allendorf

    2012-01-01

    Establishing if species contractions were the result of natural phenomena or human induced landscape changes is essential for managing natural populations. Fishers (Martes pennanti) in California occur in two geographically and genetically isolated populations in the northwestern mountains and southern Sierra Nevada. Their isolation is hypothesized to have resulted...

  17. Populations of migratory bird species that did not show a phenological response to climate change are declining.

    PubMed

    Møller, Anders Pape; Rubolini, Diego; Lehikoinen, Esa

    2008-10-21

    Recent rapid climatic changes are associated with dramatic changes in phenology of plants and animals, with optimal timing of reproduction advancing considerably in the northern hemisphere. However, some species may not have advanced their timing of breeding sufficiently to continue reproducing optimally relative to the occurrence of peak food availability, thus becoming mismatched compared with their food sources. The degree of mismatch may differ among species, and species with greater mismatch may be characterized by declining populations. Here we relate changes in spring migration timing by 100 European bird species since 1960, considered as an index of the phenological response of bird species to recent climate change, to their population trends. Species that declined in the period 1990-2000 did not advance their spring migration, whereas those with stable or increasing populations advanced their migration considerably. On the other hand, population trends during 1970-1990 were predicted by breeding habitat type, northernmost breeding latitude, and winter range (with species of agricultural habitat, breeding at northern latitudes, and wintering in Africa showing an unfavorable conservation status), but not by change in migration timing. The association between population trend in 1990-2000 and change in migration phenology was not confounded by any of the previously identified predictors of population trends in birds, or by similarity in phenotype among taxa due to common descent. Our findings imply that ecological factors affecting population trends can change over time and suggest that ongoing climatic changes will increasingly threaten vulnerable migratory bird species, augmenting their extinction risk.

  18. Patterns of growth and body condition in sea otters from the Aleutian archipelago before and after the recent population decline

    USGS Publications Warehouse

    Laidre, K.L.; Estes, J.A.; Tinker, M.T.; Bodkin, J.; Monson, D.; Schneider, K.

    2006-01-01

    3In addition to larger asymptotic values for mass and length, the rate of growth towards asymptotic values was more rapid in the 1990s than in the 1960s/70s: sea otters reached 95% of asymptotic body mass and body length 1–2 years earlier in the 1990s.4Body condition (as measured by the log mass/log length ratio) was significantly greater in males than in females. There was also an increasing trend from the 1960s/70s through 2004 despite much year-to-year variation.5Population age structures differed significantly between the 1960s/70s and the 1990s with the latter distribution skewed toward younger age classes (indicating an altered lxfunction) suggesting almost complete relaxation of age-dependent mortality patterns (i.e. those typical of food-limited populations).6This study spanned a period of time over which the population status of sea otters in the Aleutian archipelago declined precipitously from levels at or near equilibrium densities at some islands in the 1960s/70s to < 5% of estimated carrying capacity by the late 1990s. The results of this study indicate an improved overall health of sea otters over the period of decline and suggest that limited nutritional resources were not the cause of the observed reduced population abundance. Our findings are consistent with the hypothesis that the decline was caused by increased killer whale predation.

  19. Genetic signals of ancient decline in Aleppo pine populations at the species' southwestern margins in the Mediterranean Basin.

    PubMed

    Salim, Kamari; Naydenov, Krassimir D; Benyounes, Haloui; Tremblay, Francine; Latifa, El Hafid; Wahid, Nadya; Valeria, Osvaldo

    2010-10-01

    Microsatellite markers were used to characterize the structure of genetic diversity in natural Moroccan Aleppo pine (Pinus halepensis Mill.) populations, the most southwesterly marginal populations of the species in the Mediterranean Basin. Twenty-two natural populations and one artificial population, located in four regions covering most of the natural range of P. halepensis in the country, were sampled. Across this range, towards the south and west (and towards high altitudes) the populations become increasingly discrete and discontinuous. The nuclear microsatellite marker analysis suggests that a large proportion of the Aleppo pines in Morocco have derived from a single genetic lineage, represented by a central group of 11 of the examined populations located in the High and Middle Atlas Mountains. In addition, two smaller groups, represented by the marginal southwestern High Atlas populations, and three still smaller north / northeastern groups of populations located in the Rif and northeast Middle Atlas Mountains, could be genetically distinguished. Further, coalescence analysis of historical demographic population patterns suggests that ancient bottlenecks occurred in all of the natural populations. However, the population differentiation and genetic diversity levels we found were good (F(st) =15.47), presumably because of the species' good potential for long-distance dispersal of seeds and high invasive capacity, which appear to have maintained a state of stable near-equilibrium, meta-population dynamics since ancient times.

  20. Canary in the coal mine: Historical oxygen decline in the Gulf of St. Lawrence due to large scale climate changes

    NASA Astrophysics Data System (ADS)

    Claret, M.; Galbraith, E. D.; Palter, J. B.; Gilbert, D.; Bianchi, D.; Dunne, J. P.

    2016-02-01

    The regional signature of anthropogenic climate change on the atmosphere and upper ocean is often difficult to discern from observational timeseries, dominated as they are by decadal climate variability. Here we argue that a long-term decline of dissolved oxygen concentrations observed in the Gulf of S. Lawrence (GoSL) is consistent with anthropogenic climate change. Oxygen concentrations in the GoSL have declined markedly since 1930 due primarily to an increase of oxygen-poor North Atlantic Central Waters relative to Labrador Current Waters (Gilbert et al. 2005). We compare these observations to a climate warming simulation using a very high-resolution global coupled ocean-atmospheric climate model. The numerical model (CM2.6), developed by the Geophysical Fluid Dynamics Laboratory, is strongly eddying and includes a biogeochemical module with dissolved oxygen. The warming scenario shows that oxygen in the GoSL decreases and it is associated to changes in western boundary currents and wind patterns in the North Atlantic. We speculate that the large-scale changes behind the simulated decrease in GoSL oxygen have also been at play in the real world over the past century, although they are difficult to resolve in noisy atmospheric data.

  1. On the decline of the Rusty Blackbird and the use of ornithological literature to document long-term population trends

    USGS Publications Warehouse

    Greenberg, R.; Droege, S.

    1999-01-01

    Unlike most North American blackbirds, Rusty Blackbirds (Euphagus carolensis) have shown steep population declines. Declines of approximately 90% are indicated for three recent decades from the Breeding Bird Survey, Christmas Bird Counts, and Quebec Checklist Program. Analyses of abundance classifications in bird distribution books and annotated checklists reveal an overlooked but long-term decline dating back to at least the early part of this century. Rusty Blackbirds were described as very common to abundant in 5656 of the pre-192O published accounts, 19% of the 1921-1950 accounts, and only 7% of the post-1950 accounts. Rusty Blackbirds were described as uncommon in none of the pre-1950 accounts, 18% of the 1951-1980 accounts, and 43% of the post-1980 accounts. A similar pattern was found for analyses based on local checklists. Destruction of wooded wetlands on wintering grounds, acid precipitation, and the conversion of boreal forest wetlands could have contributed to these declines. Systematic analysis of regional guides and checklists provides a valuable tool for examining large-scale and long-term population changes in birds.

  2. Detection and effects of harmful algal toxins in Scottish harbour seals and potential links to population decline.

    PubMed

    Jensen, Silje-Kristin; Lacaze, Jean-Pierre; Hermann, Guillaume; Kershaw, Joanna; Brownlow, Andrew; Turner, Andrew; Hall, Ailsa

    2015-04-01

    Over the past 15 years or so, several Scottish harbour seal (Phoca vitulina) populations have declined in abundance and several factors have been considered as possible causes, including toxins from harmful algae. Here we explore whether a link could be established between two groups of toxins, domoic acid (DA) and saxitoxins (STXs), and the decline in the harbour seal populations in Scotland. We document the first evidence that harbour seals are exposed to both DA and STXs from consuming contaminated fish. Both groups of toxins were found in urine and faeces sampled from live captured (n = 162) and stranded animals (n = 23) and in faecal samples collected from seal haul-out sites (n = 214) between 2008 and 2013. The proportion of positive samples and the toxins levels measured in the excreta were significantly higher in areas where harbour seal abundance is in decline. There is also evidence that DA has immunomodulatory effects in harbour seals, including lymphocytopenia and monocytosis. Scottish harbour seals are exposed to DA and STXs through contaminated prey at potentially lethal levels and with this evidence we suggest that exposure to these toxins are likely to be important factors driving the harbour seal decline in some regions of Scotland.

  3. Dietary traces of neonicotinoid pesticides as a cause of population declines in honey bees: an evaluation by Hill's epidemiological criteria.

    PubMed

    Cresswell, James E; Desneux, Nicolas; vanEngelsdorp, Dennis

    2012-06-01

    Honey bees are important pollinators of both crops and wild plants. Pesticide regimes that threaten their sustainability should therefore be assessed. As an example, evidence that the agricultural use of neonicotinoid pesticides is a cause of the recently observed declines in honey bees is examined. The aim is to define exacting demographic conditions for a detrimental factor to precipitate a population decline, and Hill's epidemiological 'causality criteria' are employed as a structured process for making an expert judgement about the proposition that trace dietary neonicotinoids in nectar and pollen cause population declines in honey bees. In spite of the absence of decisive experimental results, the analysis shows that, while the proposition is a substantially justified conjecture in the context of current knowledge, it is also substantially contraindicated by a wide variety of circumstantial epidemiological evidence. It is concluded that dietary neonicotinoids cannot be implicated in honey bee declines, but this position is provisional because important gaps remain in current knowledge. Avenues for further investigations to resolve this longstanding uncertainty are therefore identified. Copyright © 2012 Society of Chemical Industry.

  4. Removal of nonnative fish results in population expansion of a declining amphibian (mountain yellow-legged frog, Rana muscosa)

    PubMed Central

    KNAPP, Roland A.; BOIANO, Daniel M.; VREDENBURG, Vance T.

    2007-01-01

    The mountain yellow-legged frog (Rana muscosa) was once a common inhabitant of the Sierra Nevada (California, USA), but has declined precipitously during the past century due in part to the introduction of nonnative fish into naturally fishless habitats. The objectives of the current study were to describe (1) the effect of fish removal from three lakes (located in two watersheds) on the small, remnant R. muscosa populations inhabiting those lakes, and (2) the initial development of metapopulation structure in each watershed as R. muscosa from expanding populations in fish-removal lakes dispersed to adjacent habitats. At all three fish-removal lakes, R. muscosa population densities increased significantly following the removal of predatory fish. The magnitude of these increases was significantly greater than that observed over the same time period in R. muscosa populations inhabiting control lakes that remained in their natural fishless condition. Following these population increases, R. muscosa dispersed to adjacent suitable (but unoccupied) sites, moving between 200 and 900 m along streams or across dry land. Together, these results suggest that large-scale removal of introduced fish could result in at least partial reversal of the decline of R. muscosa. Continued monitoring of R. muscosa at the fish-removal sites will be necessary to determine whether the positive effects of fish eradication are sustained over the long-term, especially in light of the increasingly important role played by an emerging infectious disease (chytridiomycosis, caused by Batrachochytrium dendrobatidis) in influencing R. muscosa populations. PMID:17396156

  5. Rise and fall of a wolf population: genetic diversity and structure during recovery, rapid expansion and drastic decline.

    PubMed

    Jansson, E; Ruokonen, M; Kojola, I; Aspi, J

    2012-11-01

    The grey wolves (Canis lupus) of Finland have had a varied history, with a period of rapid population expansion after the mid-1990s followed by a decline with a current census size of about 140 wolves. Here, we investigate the impact of unstable population size and connectivity on genetic diversity and structure in a long-term genetic study of 298 Finnish wolves born in 1995-2009 and genotyped for 17 microsatellite loci. During the initial recovery and prior to population expansion, genetic diversity was high (1995-1997: LD-N(e)  = 67.2; H(o)  = 0.749; H(e)  = 0.709) despite a small census size and low number of breeders (N(c)  < 100; N(b)  < 10) likely reflecting the status of the Russian source population. Surprisingly, observed heterozygosity decreased significantly during the study period (t = -2.643, P = 0.021) despite population expansion, likely a result of an increase in inbreeding (F(IS)  = 0.108 in 2007-2009) owing to a low degree of connectivity with adjacent Russian wolf population (m = 0.016-0.090; F(ST)  = 0.086, P < 0.001) and population crash after 2006. However, population growth had a temporary positive impact on N(e) and number of family lines. This study shows that even strong population growth alone might not be adequate to retain genetic diversity, especially when accompanied with low amount of subsequent gene flow and population decline.

  6. Factors affecting population dynamics of leaf beetles in a subarctic region: The interplay between climate warming and pollution decline.

    PubMed

    Zvereva, Elena L; Hunter, Mark D; Zverev, Vitali; Kozlov, Mikhail V

    2016-10-01

    Understanding the mechanisms by which abiotic drivers, such as climate and pollution, influence population dynamics of animals is important for our ability to predict the population trajectories of individual species under different global change scenarios. We monitored four leaf beetle species (Coleoptera: Chrysomelidae) feeding on willows (Salix spp.) in 13 sites along a pollution gradient in subarctic forests of north-western Russia from 1993 to 2014. During a subset of years, we also measured the impacts of natural enemies and host plant quality on the performance of one of these species, Chrysomela lapponica. Spring and fall temperatures increased by 2.5-3°C during the 21-year observation period, while emissions of sulfur dioxide and heavy metals from the nickel-copper smelter at Monchegorsk decreased fivefold. However, contrary to predictions of increasing herbivory with climate warming, and in spite of discovered increase in host plant quality with increase in temperatures, none of the beetle species became more abundant during the past 20years. No directional trends were observed in densities of either Phratora vitellinae or Plagiodera versicolora, whereas densities of both C. lapponica and Gonioctena pallida showed a simultaneous rapid 20-fold decline in the early 2000s, remaining at very low levels thereafter. Time series analysis and model selection indicated that these abrupt population declines were associated with decreases in aerial emissions from the smelter. Observed declines in the population densities of C. lapponica can be explained by increases in mortality from natural enemies due to the combined action of climate warming and declining pollution. This pattern suggests that at least in some tri-trophic systems, top-down factors override bottom-up effects and govern the impacts of environmental changes on insect herbivores. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Decline in perfluorooctane sulfonate and perfluorooctanoate serum concentrations in an Australian population from 2002 to 2011.

    PubMed

    Toms, L-M L; Thompson, J; Rotander, A; Hobson, P; Calafat, A M; Kato, K; Ye, X; Broomhall, S; Harden, F; Mueller, J F

    2014-10-01

    Some perfluoroalkyl and polyfluoroalkyl substances (PFASs) have become widespread pollutants detected in human and wildlife samples worldwide. The main objective of this study was to assess temporal trends of PFAS concentrations in human blood in Australia over the last decade (2002-2011), taking into consideration age and sex trends. Pooled human sera from 2002/03 (n=26); 2008/09 (n=24) and 2010/11 (n=24) from South East Queensland, Australia were obtained from de-identified surplus pathology samples and compared with samples collected previously from 2006/07 (n=84). A total of 9775 samples in 158 pools were available for an assessment of PFASs. Stratification criteria included sex and age: <16 years (2002/03 only); 0-4 (2006/07, 2008/09, 2010/11); 5-15 (2006/07, 2008/09, 2010/11); 16-30; 31-45; 46-60; and >60 years (all collection periods). Sera were analyzed using on-line solid-phase extraction coupled to high-performance liquid chromatography-isotope dilution-tandem mass spectrometry. Perfluorooctane sulfonate (PFOS) was detected in the highest concentrations ranging from 5.3-19.2 ng/ml (2008/09) to 4.4-17.4 ng/ml (2010/11). Perfluorooctanoate (PFOA) was detected in the next highest concentration ranging from 2.8-7.3 ng/ml (2008/09) to 3.1-6.5 ng/ml (2010/11). All other measured PFASs were detected at concentrations <1 ng/ml with the exception of perfluorohexane sulfonate which ranged from 1.2-5.7 ng/ml (08/09) and 1.4-5.4 ng/ml (10/11). The mean concentrations of both PFOS and PFOA in the 2010/11 period compared to 2002/03 were lower for all adult age groups by 56%. For 5-15 year olds, the decrease was 66% (PFOS) and 63% (PFOA) from 2002/03 to 2010/11. For 0-4 year olds the decrease from 2006/07 (when data were first available for this age group) was 50% (PFOS) and 22% (PFOA). This study provides strong evidence for decreasing serum PFOS and PFOA concentrations in an Australian population from 2002 through 2011. Age trends were variable and concentrations were

  8. Decline in perfluorooctane sulfonate and perfluorooctanoate serum concentrations in an Australian population from 2002 to 2011

    PubMed Central

    Toms, L.-M.L.; Thompson, J.; Rotander, A.; Hobson, P.; Calafat, A.M.; Kato, K.; Ye, X.; Broomhall, S.; Harden, F.; Mueller, J.F.

    2016-01-01

    Some perfluoroalkyl and polyfluoroalkyl substances (PFASs) have become widespread pollutants detected in human and wildlife samples worldwide. The main objective of this study was to assess temporal trends of PFAS concentrations in human blood in Australia over the last decade (2002–2011), taking into consideration age and sex trends. Pooled human sera from 2002/03 (n = 26); 2008/09 (n = 24) and 2010/11 (n = 24) from South East Queensland, Australia were obtained from de-identified surplus pathology samples and compared with samples collected previously from 2006/07 (n = 84). A total of 9775 samples in 158 pools were available for an assessment of PFASs. Stratification criteria included sex and age: <16 years (2002/03 only); 0–4 (2006/07, 2008/09, 2010/11); 5–15 (2006/07, 2008/09, 2010/11); 16–30; 31–45; 46–60; and >60 years (all collection periods). Sera were analyzed using on-line solid-phase extraction coupled to high-performance liquid chromatography–isotope dilution-tandem mass spectrometry. Perfluorooctane sulfonate (PFOS) was detected in the highest concentrations ranging from 5.3–19.2 ng/ml (2008/09) to 4.4–17.4 ng/ml (2010/11). Perfluorooctanoate (PFOA) was detected in the next highest concentration ranging from 2.8–7.3 ng/ml (2008/09) to 3.1–6.5 ng/ml (2010/11). All other measured PFASs were detected at concentrations <1 ng/ml with the exception of perfluorohexane sulfonate which ranged from 1.2–5.7 ng/ml (08/09) and 1.4–5.4 ng/ml (10/11). The mean concentrations of both PFOS and PFOA in the 2010/11 period compared to 2002/03 were lower for all adult age groups by 56%. For 5–15 year olds, the decrease was 66% (PFOS) and 63% (PFOA) from 2002/03 to 2010/11. For 0–4 year olds the decrease from 2006/07 (when data were first available for this age group) was 50% (PFOS) and 22% (PFOA). This study provides strong evidence for decreasing serum PFOS and PFOA concentrations in an Australian population from 2002 through 2011. Age trends

  9. [A historical survey of international migration of China population].

    PubMed

    Zhu, G

    1987-07-01

    Chinese migration trends in various periods of China's history are discussed. From the earliest times to the present, migration patterns seem unique to each period: 1) Early period of emigration (Qin-Tang Dynasties): The earliest recorded instance of emigration occurred during the Qin dynasty when a traveler went to what is now the Philippines. In the following dynasties, even though migration was limited to religious men and merchants who went abroad and returned to China, the process of migrating was established. 2) Tang to Ming Dynasties (Self-initiated migration): Tang Dynasty records show the beginnings of Chinese residence abroad in Arabia. Land and sea travel developed further, and majority of emigres left China for political, religious or economic reasons. 3) Post-Ming Dynasty (Forced migration): This is a period beginning with the Opium War, where 2 groups, indentured servants and those who were able to purchase their own fare, emigrated as laborers because of necessity. The population on the coast, which had risen dramatically by the 1900's, was subject to war, official corruption, poverty and disease. Migration reached a peak between 1851-1875 when 1,280,000 Chinese left the country, settling mostly in Southeast Asia. Between 1847-1873, it is estimated that between 22%-64% perished along the way. 4) WWI-1949 (Motivated migration): The consequences of 2 world wars and the Great Depression were cause for another mass migration from China for political and economic reasons. This time, however, emigres were not limited to the very poor; also, a large number of overseas Chinese eventually returned to the mainland. Between 1930-34, 350,000 more Chinese returned than left. 5) Post-1949 (A new era): In the 1950s large numbers of overseas Chinese returned to the mainland. In 1978-82, over 4000 Chinese returned to Guangdong alone. A new phenomenon has appeared: migration tends to be limited to visits to relatives or to travel for pleasure or education.

  10. Autosomal genetic diversity in non-breed horses from eastern Eurasia provides insights into historical population movements.

    PubMed

    Warmuth, Vera; Manica, Andrea; Eriksson, Anders; Barker, Graeme; Bower, Mim

    2013-02-01

    Many events in the history of eastern Eurasia, including the process of domestication itself, the initial spread of domestic horses and subsequent movements, are believed to have affected the genetic structure of domestic horse populations in this area. We investigated levels of within- and between-population genetic diversity in 'non-breed horses' (working horses sampled in remote areas) from 17 locations in Asia and parts of Eastern Europe, using 26 autosomal microsatellite loci. Non-breed horses have not been subject to the same intensity of artificial selection and closed breeding as have most breed animals and are thus expected to better reflect the population history of domestic horses. Despite geographic distances of between 300 and 7000 km between sampling locations, pairwise F (ST) was very low (range: <0.001 to -0.033), suggesting historically high levels of gene flow. Our analyses of non-breed horses revealed a pattern of isolation by distance and a significant decline in genetic diversity (expected heterozygosity and allelic richness) from east to west, consistent with a westward expansion of horses out of East Asia. Although the timing of this putative expansion is unclear, our results highlight the benefit of studying animals that do not belong to particular breeds when investigating aspects of a population's history. © 2012 The Authors, Animal Genetics © 2012 Stichting International Foundation for Animal Genetics.

  11. Amphibian populations in the terrestrial environment: Is there evidence of declines of terrestrial forest amphibians in northwestern California?

    USGS Publications Warehouse

    Welsh, H.H.; Fellers, G.M.; Lind, A.J.

    2007-01-01

    Amphibian declines have been documented worldwide; however the vast majority are species associated with aquatic habitats. Information on the status and trends of terrestrial amphibians is almost entirely lacking. Here we use data collected across a 12-yr period (sampling from 1984-86 and from 1993-95) to address the question of whether evidence exists for declines among terrestrial amphibians in northwestern California forests. The majority of amphibians, both species and relative numbers, in these forests are direct-developing salamanders of the family Plethodontidae. We examined amphibian richness and evenness, and the relative abundances of the four most common species of plethodontid salamanders. We examined evidence of differences between years in two ecological provinces (coastal and interior) and across young, mature, and late seral forests and with reference to a moisture gradient from xeric to hydric within late seral forests. We found evidence of declines in species richness across years on late seral mesic stands and in the coastal ecological province, but these differences appeared to be caused by differences in the detection of rarer species, rather than evidence of an overall pattern. We also found differences among specific years in numbers of individuals of the most abundant species, Ensatina eschscholtzii, but these differences also failed to reflect a consistent pattern of declines between the two decadal sample periods. Results showing differences in richness, evenness, and relative abundances along both the seral and moisture continua were consistent with previous research. Overall, we found no compelling evidence of a downward trend in terrestrial plethodontid salamanders. We believe that continued monitoring of terrestrial salamander populations is important to understanding mechanisms of population declines in amphibian species. Copyright 2007 Society for the Study of Amphibians and Reptiles.

  12. Declining brown-headed cowbird (Molothrus ater) populations are associated with landscape-specific reductions in brood parasitism and increases in songbird productivity

    Treesearch

    W. Andrew Cox; Frank R., III Thompson; Brian Root; John Faaborg; Csaba. Moskat

    2012-01-01

    Many songbird species have experienced significant population declines, partly because of brood parasitism by the Brown-headed Cowbird (Molothrus ater), which is positively associated with increasing landscape forest cover in the midwestern United States. However, cowbirds are also experiencing long-term population declines, which should reduce...

  13. Vitamin D and Memory Decline: Two Population-Based Prospective Studies.

    PubMed

    Kuźma, Elżbieta; Soni, Maya; Littlejohns, Thomas J; Ranson, Janice M; van Schoor, Natasja M; Deeg, Dorly J H; Comijs, Hannie; Chaves, Paulo H M; Kestenbaum, Bryan R; Kuller, Lewis H; Lopez, Oscar L; Becker, James T; Langa, Kenneth M; Henley, William E; Lang, Iain A; Ukoumunne, Obioha C; Llewellyn, David J

    2016-01-01

    Vitamin D deficiency has been linked with dementia risk, cognitive decline, and executive dysfunction. However, the association with memory remains largely unknown. To investigate whether low serum 25-hydroxyvitamin D (25(OH)D) concentrations are associated with memory decline. We used data on 1,291 participants from the US Cardiovascular Health Study (CHS) and 915 participants from the Dutch Longitudinal Aging Study Amsterdam (LASA) who were dementia-free at baseline, had valid vitamin D measurements, and follow-up memory assessments. The Benton Visual Retention Test (in the CHS) and Rey's Auditory Verbal Learning Test (in the LASA) were used to assess visual and verbal memory, respectively. In the CHS, those moderately and severely deficient in serum 25(OH)D changed -0.03 SD (95% CI: -0.06 to 0.01) and -0.10 SD (95% CI: -0.19 to -0.02) per year respectively in visual memory compared to those sufficient (p = 0.02). In the LASA, moderate and severe deficiency in serum 25(OH)D was associated with a mean change of 0.01 SD (95% CI: -0.01 to 0.02) and -0.01 SD (95% CI: -0.04 to 0.02) per year respectively in verbal memory compared to sufficiency (p = 0.34). Our findings suggest an association between severe vitamin D deficiency and visual memory decline but no association with verbal memory decline. They warrant further investigation in prospective studies assessing different memory subtypes.

  14. Spatio-temporal variation in age structure and abundance of the endangered snail kite: Pooling across regions masks a declining and aging population

    USGS Publications Warehouse

    Reichert, Brian E.; Kendall, William; Fletcher, Robert J.; Kitchens, Wiley M.

    2016-01-01

    While variation in age structure over time and space has long been considered important for population dynamics and conservation, reliable estimates of such spatio-temporal variation in age structure have been elusive for wild vertebrate populations. This limitation has arisen because of problems of imperfect detection, the potential for temporary emigration impacting assessments of age structure, and limited information on age. However, identifying patterns in age structure is important for making reliable predictions of both short- and long-term dynamics of populations of conservation concern. Using a multistate superpopulation estimator, we estimated region-specific abundance and age structure (the proportion of individuals within each age class) of a highly endangered population of snail kites for two separate regions in Florida over 17 years (1997–2013). We find that in the southern region of the snail kite—a region known to be critical for the long-term persistence of the species—the population has declined significantly since 1997, and during this time, it has increasingly become dominated by older snail kites (> 12 years old). In contrast, in the northern region—a region historically thought to serve primarily as drought refugia—the population has increased significantly since 2007 and age structure is more evenly distributed among age classes. Given that snail kites show senescence at approximately 13 years of age, where individuals suffer higher mortality rates and lower breeding rates, these results reveal an alarming trend for the southern region. Our work illustrates the importance of accounting for spatial structure when assessing changes in abundance and age distribution and the need for monitoring of age structure in imperiled species.

  15. Spatio-Temporal Variation in Age Structure and Abundance of the Endangered Snail Kite: Pooling across Regions Masks a Declining and Aging Population

    PubMed Central

    Kendall, William L.; Fletcher, Robert J.; Kitchens, Wiley M.

    2016-01-01

    While variation in age structure over time and space has long been considered important for population dynamics and conservation, reliable estimates of such spatio-temporal variation in age structure have been elusive for wild vertebrate populations. This limitation has arisen because of problems of imperfect detection, the potential for temporary emigration impacting assessments of age structure, and limited information on age. However, identifying patterns in age structure is important for making reliable predictions of both short- and long-term dynamics of populations of conservation concern. Using a multistate superpopulation estimator, we estimated region-specific abundance and age structure (the proportion of individuals within each age class) of a highly endangered population of snail kites for two separate regions in Florida over 17 years (1997–2013). We find that in the southern region of the snail kite—a region known to be critical for the long-term persistence of the species—the population has declined significantly since 1997, and during this time, it has increasingly become dominated by older snail kites (> 12 years old). In contrast, in the northern region—a region historically thought to serve primarily as drought refugia—the population has increased significantly since 2007 and age structure is more evenly distributed among age classes. Given that snail kites show senescence at approximately 13 years of age, where individuals suffer higher mortality rates and lower breeding rates, these results reveal an alarming trend for the southern region. Our work illustrates the importance of accounting for spatial structure when assessing changes in abundance and age distribution and the need for monitoring of age structure in imperiled species. PMID:27681854

  16. A historical review of managed honey bee populations in Europe and the United States and the factors that may affect them.

    PubMed

    Vanengelsdorp, Dennis; Meixner, Marina Doris

    2010-01-01

    Honey bees are a highly valued resource around the world. They are prized for their honey and wax production and depended upon for pollination of many important crops. While globally honey bee populations have been increasing, the rate of increase is not keeping pace with demand. Further, honey bee populations have not been increasing in all parts of the world, and have declined in many nations in Europe and in North America. Managed honey bee populations are influenced by many factors including diseases, parasites, pesticides, the environment, and socio-economic factors. These factors can act alone or in combination with each other. This review highlights the present day value of honey bees, followed by a detailed description of some of the historical and present day factors that influence honey bee populations, with particular emphasis on colony populations in Europe and the United States.

  17. Modern analyses on an historical data set: skull morphology of Italian red squirrel populations

    PubMed Central

    Amori, Giovanni; Aloise, Gaetano; Luiselli, Luca

    2014-01-01

    Abstract Recent molecular evidence suggests that Sciurus vulgaris populations from Calabria (southern Italy) are distinct from those occurring in northern and central Italy. Here, we re-analyzed using multivariate and univariate techniques an historical dataset provided by Cavazza (1913), who documented measurements for the now extinct squirrel population from Campania. Both univariate and multivariate analyses confirmed that the sample from Calabria was homogenous and relatively distinct compared to the rest of the squirrel samples. PMID:24478584

  18. Ecosystem scale declines in elk recruitment and population growth with wolf colonization: a before-after-control-impact approach.

    PubMed

    Christianson, David; Creel, Scott

    2014-01-01

    The reintroduction of wolves (Canis lupus) to Yellowstone provided the unusual opportunity for a quasi-experimental test of the effects of wolf predation on their primary prey (elk--Cervus elaphus) in a system where top-down, bottom-up, and abiotic forces on prey population dynamics were closely and consistently monitored before and after reintroduction. Here, we examined data from 33 years for 12 elk population segments spread across southwestern Montana and northwestern Wyoming in a large scale before-after-control-impact analysis of the effects of wolves on elk recruitment and population dynamics. Recruitment, as measured by the midwinter juvenile∶female ratio, was a strong determinant of elk dynamics, and declined by 35% in elk herds colonized by wolves as annual population growth shifted from increasing to decreasing. Negative effects of population density and winter severity on recruitment, long recognized as important for elk dynamics, were detected in uncolonized elk herds and in wolf-colonized elk herds prior to wolf colonization, but not after wolf colonization. Growing season precipitation and harvest had no detectable effect on recruitment in either wolf treatment or colonization period, although harvest rates of juveniles∶females declined by 37% in wolf-colonized herds. Even if it is assumed that mortality due to predation is completely additive, liberal estimates of wolf predation rates on juvenile elk could explain no more than 52% of the total decline in juvenile∶female ratios in wolf-colonized herds, after accounting for the effects of other limiting factors. Collectively, these long-term, large-scale patterns align well with prior studies that have reported substantial decrease in elk numbers immediately after wolf recolonization, relatively weak additive effects of direct wolf predation on elk survival, and decreased reproduction and recruitment with exposure to predation risk from wolves.

  19. Ecosystem Scale Declines in Elk Recruitment and Population Growth with Wolf Colonization: A Before-After-Control-Impact Approach

    PubMed Central

    Christianson, David; Creel, Scott

    2014-01-01

    The reintroduction of wolves (Canis lupus) to Yellowstone provided the unusual opportunity for a quasi-experimental test of the effects of wolf predation on their primary prey (elk – Cervus elaphus) in a system where top-down, bottom-up, and abiotic forces on prey population dynamics were closely and consistently monitored before and after reintroduction. Here, we examined data from 33 years for 12 elk population segments spread across southwestern Montana and northwestern Wyoming in a large scale before-after-control-impact analysis of the effects of wolves on elk recruitment and population dynamics. Recruitment, as measured by the midwinter juvenile∶female ratio, was a strong determinant of elk dynamics, and declined by 35% in elk herds colonized by wolves as annual population growth shifted from increasing to decreasing. Negative effects of population density and winter severity on recruitment, long recognized as important for elk dynamics, were detected in uncolonized elk herds and in wolf-colonized elk herds prior to wolf colonization, but not after wolf colonization. Growing season precipitation and harvest had no detectable effect on recruitment in either wolf treatment or colonization period, although harvest rates of juveniles∶females declined by 37% in wolf-colonized herds. Even if it is assumed that mortality due to predation is completely additive, liberal estimates of wolf predation rates on juvenile elk could explain no more than 52% of the total decline in juvenile∶female ratios in wolf-colonized herds, after accounting for the effects of other limiting factors. Collectively, these long-term, large-scale patterns align well with prior studies that have reported substantial decrease in elk numbers immediately after wolf recolonization, relatively weak additive effects of direct wolf predation on elk survival, and decreased reproduction and recruitment with exposure to predation risk from wolves. PMID:25028933

  20. Population structure and genotype-phenotype associations in a collection of oat landraces and historic cultivars.

    USDA-ARS?s Scientific Manuscript database

    Population structure and genetic architecture of phenotypic traits in oat (Avena sativa L.) remain relatively under-researched compared to other small grain species. This study explores the historic context of current elite germplasm, including phenotypic and genetic characterization, with a partic...

  1. [Cities and oil. Historical and prospective aspects of the urban population of Venezuela].

    PubMed

    Papail, J; Picquet, M

    1989-01-01

    The authors present a historical overview of urbanization in Venezuela. The impact of the oil economy on population change and spatial distribution is emphasized. A typology of cities based on socioeconomic function and on a demographic classification of urban centers is devised. Future trends in urbanization are also considered. (SUMMARY IN ENG)

  2. Patterns of growth and body condition in sea otters from the Aleutian archipelago before and after the recent population decline.

    PubMed

    Laidre, K L; Estes, J A; Tinker, M T; Bodkin, J; Monson, D; Schneider, K

    2006-07-01

    1. Growth models for body mass and length were fitted to data collected from 1842 sea otters Enhydra lutris shot or live-captured throughout south-west Alaska between 1967 and 2004. Growth curves were constructed for each of two main year groups: 1967-71 when the population was at or near carrying capacity and 1992-97 when the population was in steep decline. Analyses of data collected from animals caught during 2004, when the population density was very low, were precluded by a small sample size and consequently only examined incidentally to the main growth curves. 2. Growth curves demonstrated a significant increase in body mass and body length at age in the 1990s. Asymptotic values of body mass were 12-18% higher in the 1990s than in the 1960s/70s, and asymptotic values for body length were 10-11% higher between the same periods. Data collected in 2004 suggest a continued increase in body size, with nearly all data points for mass and length falling significantly above the 1990s growth curves. 3. In addition to larger asymptotic values for mass and length, the rate of growth towards asymptotic values was more rapid in the 1990s than in the 1960s/70s: sea otters reached 95% of asymptotic body mass and body length 1-2 years earlier in the 1990s. 4. Body condition (as measured by the log mass/log length ratio) was significantly greater in males than in females. There was also an increasing trend from the 1960s/70s through 2004 despite much year-to-year variation. 5. Population age structures differed significantly between the 1960s/70s and the 1990s with the latter distribution skewed toward younger age classes (indicating an altered lx function) suggesting almost complete relaxation of age-dependent mortality patterns (i.e. those typical of food-limited populations). 6. This study spanned a period of time over which the population status of sea otters in the Aleutian archipelago declined precipitously from levels at or near equilibrium densities at some islands in

  3. Summary of the evidence on modifiable risk factors for cognitive decline and dementia: A population-based perspective.

    PubMed

    Baumgart, Matthew; Snyder, Heather M; Carrillo, Maria C; Fazio, Sam; Kim, Hye; Johns, Harry

    2015-06-01

    An estimated 47 million people worldwide are living with dementia in 2015, and this number is projected to triple by 2050. In the absence of a disease-modifying treatment or cure, reducing the risk of developing dementia takes on added importance. In 2014, the World Dementia Council (WDC) requested the Alzheimer's Association evaluate and report on the state of the evidence on modifiable risk factors for cognitive decline and dementia. This report is a summary of the Association's evaluation, which was presented at the October 2014 WDC meeting. The Association believes there is sufficient evidence to support the link between several modifiable risk factors and a reduced risk for cognitive decline, and sufficient evidence to suggest that some modifiable risk factors may be associated with reduced risk of dementia. Specifically, the Association believes there is sufficiently strong evidence, from a population-based perspective, to conclude that regular physical activity and management of cardiovascular risk factors (diabetes, obesity, smoking, and hypertension) reduce the risk of cognitive decline and may reduce the risk of dementia. The Association also believes there is sufficiently strong evidence to conclude that a healthy diet and lifelong learning/cognitive training may also reduce the risk of cognitive decline.

  4. Ginkgo Biloba Extract and Long-Term Cognitive Decline: A 20-Year Follow-Up Population-Based Study

    PubMed Central

    Amieva, Hélène; Meillon, Céline; Helmer, Catherine; Barberger-Gateau, Pascale; Dartigues, Jean François

    2013-01-01

    Background Numerous studies have looked at the potential benefits of various nootropic drugs such as Ginkgo biloba extract (EGb761®; Tanakan®) and piracetam (Nootropyl®) on age-related cognitive decline often leading to inconclusive results due to small sample sizes or insufficient follow-up duration. The present study assesses the association between intake of EGb761® and cognitive function of elderly adults over a 20-year period. Methods and Findings The data were gathered from the prospective community-based cohort study ‘Paquid’. Within the study sample of 3612 non-demented participants aged 65 and over at baseline, three groups were compared: 589 subjects reporting use of EGb761® at at least one of the ten assessment visits, 149 subjects reporting use of piracetam at one of the assessment visits and 2874 subjects not reporting use of either EGb761® or piracetam. Decline on MMSE, verbal fluency and visual memory over the 20-year follow-up was analysed with a multivariate mixed linear effects model. A significant difference in MMSE decline over the 20-year follow-up was observed in the EGb761® and piracetam treatment groups compared to the ‘neither treatment’ group. These effects were in opposite directions: the EGb761® group declined less rapidly than the ‘neither treatment’ group, whereas the piracetam group declined more rapidly (β = −0.6). Regarding verbal fluency and visual memory, no difference was observed between the EGb761® group and the ‘neither treatment’ group (respectively, β = 0.21 and β = −0.03), whereas the piracetam group declined more rapidly (respectively, β = −1.40 and β = −0.44). When comparing the EGb761® and piracetam groups directly, a different decline was observed for the three tests (respectively β = −1.07, β = −1.61 and β = −0.41). Conclusion Cognitive decline in a non-demented elderly population was lower in subjects who reported using EGb761® than in

  5. Historical and anthropogenic factors affecting the population genetic structure of Ontario's inland lake populations of Walleye (Sander vitreus).

    PubMed

    Walter, Ryan P; Cena, Christopher J; Morgan, George E; Heath, Daniel D

    2012-01-01

    Populations existing in formerly glaciated areas often display composite historical and contemporary patterns of genetic structure. For Canadian freshwater fishes, population genetic structure is largely reflective of dispersal from glacial refugia and isolation within drainage basins across a range of scales. Enhancement of sport fisheries via hatchery stocking programs and other means has the potential to alter signatures of natural evolutionary processes. Using 11 microsatellite loci genotyped from 2182 individuals, we analyzed the genetic structure of 46 inland lake walleye (Sander vitreus) populations spanning five major drainage basins within the province of Ontario, Canada. Population genetic analyses coupled with genotype assignment allowed us to: 1) characterize broad- and fine-scale genetic structure among Ontario walleye populations; and 2) determine if the observed population divergence is primarily due to natural or historical processes, or recent anthropogenic events. The partitioning of genetic variation revealed higher genetic divergence among lakes than among drainage basins or proposed ancestries-indicative of relatively high isolation among lakes, study-wide. Walleye genotypes were clustered into three major groups, likely reflective of Missourian, Mississippian, and Atlantic glacial refugial ancestry. Despite detectable genetic signatures indicative of anthropogenic influences, province-wide spatial genetic structure remains consistent with the hypothesis of dispersal from distinct glacial refugia and subsequent isolation of lakes within primary drainage basins. Our results provide a novel example of minimal impacts from fishery enhancement to the broad-scale genetic structure of inland fish populations.

  6. Adherence to a Mediterranean-type dietary pattern and cognitive decline in a community population.

    PubMed

    Tangney, Christine C; Kwasny, Mary J; Li, Hong; Wilson, Robert S; Evans, Denis A; Morris, Martha Clare

    2011-03-01

    Many of the foods abundant in the traditional Mediterranean diet, such as vegetables and fish, have been associated with slower cognitive decline. We investigated whether adherence to a Mediterranean dietary pattern or to the Healthy Eating Index-2005 (HEI-2005) is associated with cognitive change in older adults. This article is based on analyses of data from an ongoing longitudinal study in adults aged ≥65 y known as the Chicago Health and Aging Project (CHAP). CHAP participants (2280 blacks and 1510 whites) with ≥2 cognitive assessments were evaluated for adherence to 1) the Mediterranean dietary pattern (MedDiet; maximum score: 55) and 2) the HEI-2005 (maximum score: 100). For both scoring systems, higher scores connote greater adherence. Cognitive function was assessed at 3-y intervals on the basis of a composite measure of global cognition. Linear mixed models were used to examine the association of dietary scores to change in cognitive function. Mean follow-up time was 7.6 y. Mean (±SD) scores for participants were 28.2 ± 0.1 for the MedDiet and 61.2 ± 9.6 for the HEI-2005. White participants had higher energy-adjusted MedDiet scores but lower HEI-2005 scores than did black participants. Higher MedDiet scores were associated with slower rates of cognitive decline (β = +0.0014 per 1-point increase, SEE = 0.0004, P = 0.0004) after adjustment for age, sex, race, education, participation in cognitive activities, and energy. No such associations were observed for HEI-2005 scores. The Mediterranean dietary pattern as captured by the MedDiet scoring system may reduce the rate of cognitive decline with older age.

  7. Adherence to a Mediterranean-type dietary pattern and cognitive decline in a community population123

    PubMed Central

    Tangney, Christine C; Kwasny, Mary J; Li, Hong; Wilson, Robert S; Evans, Denis A; Morris, Martha Clare

    2011-01-01

    Background: Many of the foods abundant in the traditional Mediterranean diet, such as vegetables and fish, have been associated with slower cognitive decline. Objective: We investigated whether adherence to a Mediterranean dietary pattern or to the Healthy Eating Index–2005 (HEI-2005) is associated with cognitive change in older adults. Design: This article is based on analyses of data from an ongoing longitudinal study in adults aged ≥65 y known as the Chicago Health and Aging Project (CHAP). CHAP participants (2280 blacks and 1510 whites) with ≥2 cognitive assessments were evaluated for adherence to 1) the Mediterranean dietary pattern (MedDiet; maximum score: 55) and 2) the HEI-2005 (maximum score: 100). For both scoring systems, higher scores connote greater adherence. Cognitive function was assessed at 3-y intervals on the basis of a composite measure of global cognition. Linear mixed models were used to examine the association of dietary scores to change in cognitive function. Mean follow-up time was 7.6 y. Results: Mean (±SD) scores for participants were 28.2 ± 0.1 for the MedDiet and 61.2 ± 9.6 for the HEI-2005. White participants had higher energy-adjusted MedDiet scores but lower HEI-2005 scores than did black participants. Higher MedDiet scores were associated with slower rates of cognitive decline (β = +0.0014 per 1-point increase, SEE = 0.0004, P = 0.0004) after adjustment for age, sex, race, education, participation in cognitive activities, and energy. No such associations were observed for HEI-2005 scores. Conclusion: The Mediterranean dietary pattern as captured by the MedDiet scoring system may reduce the rate of cognitive decline with older age. PMID:21177796

  8. Declining trends in prevalence of Helicobacter pylori infection by birth-year in a Japanese population.

    PubMed

    Watanabe, Miki; Ito, Hidemi; Hosono, Satoyo; Oze, Isao; Ashida, Chieko; Tajima, Kazuo; Katoh, Hisato; Matsuo, Keitaro; Tanaka, Hideo

    2015-12-01

    Gastric cancer incidence and mortality have been decreasing in Japan. These decreases are likely due to a decrease in prevalence of Helicobacter pylori infection. Our aim was to characterize the trends in prevalence of H. pylori infection focused on birth-year. We carried out a cross-sectional study that included 4285 subjects who were born from 1926 to 1989. We defined H. pylori infection by the serum H. pylori antibody titer. Individuals having H. pylori infection and those with negative H. pylori antibody titer and positive pepsinogen test were defined as high-risk individuals for gastric cancer. We estimated the birth-year percent change (BPC) of the prevalence by Joinpoint regression analysis. The prevalence of H. pylori infection among the subjects born from 1927 to 1949 decreased from 54.0% to 42.0% with a BPC of -1.2%. It was followed by a rapid decline in those born between 1949 (42.0%) and 1961 (24.0%) with a BPC of -4.5%, which was followed by those born between 1961 (24.0%) and 1988 (14.0%) with a BPC of -2.1%. The proportion of high-risk individuals for gastric cancer among the subjects born from 1927 to 1942 decreased from 62.0% to 55.0% with a BPC of -0.8%. A subsequent rapid declining trend was observed in those born between 1942 (55.0%) and 1972 (18.0%) with a BPC of -3.6%, and then it became stable. These remarkable declining trends in the prevalence of H. pylori infection by birth-year would be useful to predict the future trend in gastric cancer incidence in Japan. © 2015 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer Association.

  9. Catastrophic Decline of World's Largest Primate: 80% Loss of Grauer's Gorilla (Gorilla beringei graueri) Population Justifies Critically Endangered Status.

    PubMed

    Plumptre, Andrew J; Nixon, Stuart; Kujirakwinja, Deo K; Vieilledent, Ghislain; Critchlow, Rob; Williamson, Elizabeth A; Nishuli, Radar; Kirkby, Andrew E; Hall, Jefferson S

    2016-01-01

    Grauer's gorilla (Gorilla beringei graueri), the World's largest primate, is confined to eastern Democratic Republic of Congo (DRC) and is threatened by civil war and insecurity. During the war, armed groups in mining camps relied on hunting bushmeat, including gorillas. Insecurity and the presence of several militia groups across Grauer's gorilla's range made it very difficult to assess their population size. Here we use a novel method that enables rigorous assessment of local community and ranger-collected data on gorilla occupancy to evaluate the impacts of civil war on Grauer's gorilla, which prior to the war was estimated to number 16,900 individuals. We show that gorilla numbers in their stronghold of Kahuzi-Biega National Park have declined by 87%. Encounter rate data of gorilla nests at 10 sites across its range indicate declines of 82-100% at six of these sites. Spatial occupancy analysis identifies three key areas as the most critical sites for the remaining populations of this ape and that the range of this taxon is around 19,700 km2. We estimate that only 3,800 Grauer's gorillas remain in the wild, a 77% decline in one generation, justifying its elevation to Critically Endangered status on the IUCN Red List of Threatened Species.

  10. Catastrophic Decline of World's Largest Primate: 80% Loss of Grauer's Gorilla (Gorilla beringei graueri) Population Justifies Critically Endangered Status

    PubMed Central

    Nixon, Stuart; Kujirakwinja, Deo K.; Vieilledent, Ghislain; Critchlow, Rob; Williamson, Elizabeth A.; Nishuli, Radar; Kirkby, Andrew E.; Hall, Jefferson S.

    2016-01-01

    Grauer’s gorilla (Gorilla beringei graueri), the World’s largest primate, is confined to eastern Democratic Republic of Congo (DRC) and is threatened by civil war and insecurity. During the war, armed groups in mining camps relied on hunting bushmeat, including gorillas. Insecurity and the presence of several militia groups across Grauer’s gorilla’s range made it very difficult to assess their population size. Here we use a novel method that enables rigorous assessment of local community and ranger-collected data on gorilla occupancy to evaluate the impacts of civil war on Grauer’s gorilla, which prior to the war was estimated to number 16,900 individuals. We show that gorilla numbers in their stronghold of Kahuzi-Biega National Park have declined by 87%. Encounter rate data of gorilla nests at 10 sites across its range indicate declines of 82–100% at six of these sites. Spatial occupancy analysis identifies three key areas as the most critical sites for the remaining populations of this ape and that the range of this taxon is around 19,700 km2. We estimate that only 3,800 Grauer’s gorillas remain in the wild, a 77% decline in one generation, justifying its elevation to Critically Endangered status on the IUCN Red List of Threatened Species. PMID:27760201

  11. Inferring Population Decline and Expansion From Microsatellite Data: A Simulation-Based Evaluation of the Msvar Method

    PubMed Central

    Girod, Christophe; Vitalis, Renaud; Leblois, Raphaël; Fréville, Hélène

    2011-01-01

    Reconstructing the demographic history of populations is a central issue in evolutionary biology. Using likelihood-based methods coupled with Monte Carlo simulations, it is now possible to reconstruct past changes in population size from genetic data. Using simulated data sets under various demographic scenarios, we evaluate the statistical performance of Msvar, a full-likelihood Bayesian method that infers past demographic change from microsatellite data. Our simulation tests show that Msvar is very efficient at detecting population declines and expansions, provided the event is neither too weak nor too recent. We further show that Msvar outperforms two moment-based methods (the M-ratio test and Bottleneck) for detecting population size changes, whatever the time and the severity of the event. The same trend emerges from a compilation of empirical studies. The latest version of Msvar provides estimates of the current and the ancestral population size and the time since the population started changing in size. We show that, in the absence of prior knowledge, Msvar provides little information on the mutation rate, which results in biased estimates and/or wide credibility intervals for each of the demographic parameters. However, scaling the population size parameters with the mutation rate and scaling the time with current population size, as coalescent theory requires, significantly improves the quality of the estimates for contraction but not for expansion scenarios. Finally, our results suggest that Msvar is robust to moderate departures from a strict stepwise mutation model. PMID:21385729

  12. Declining Enrollments.

    ERIC Educational Resources Information Center

    Wakefield, Howard E.; Donnelly, Richard A.

    The five sections in this loose-leaf binder are intended to provide Wisconsin school board members with information necessary for decision-making on the problem of declining enrollment. Section 1 contains information about the extent of the problem and summarizes recent trends in population and school enrollments in the nation and the state.…

  13. Trap-induced mass declines in small mammals: Mass as a population index

    Treesearch

    Dean E. Pearson; Yvette K. Ortega; Leonard F. Ruggiero

    2003-01-01

    Body mass is routinely used as an index of physical condition for comparing small-mammal populations. However, trapping effects on animals may undermine the effectiveness of body mass as an index of population health. We examined the effects of live-trapping on body mass of 3 small-mammal species: deer mice (Peromyscus maniculatus), southern red-...

  14. Declining human population but increasing residential development around protected areas in Puerto Rico

    Treesearch

    J. Castro-Prieto; S. Martinuzzi; V.C. Radeloff; D.P. Helmers; M. Quiñones; W.A. Gould

    2017-01-01

    Increasing residential development around protected areas is a major threat for protected areas worldwide, and human population growth is often the most important cause. However, population is decreasing in many regions as a result of socio-economic changes, and it is unclear how residential development around protected areas is affected in these situations. We...

  15. Drugs with anticholinergic properties, cognitive decline, and dementia in an elderly general population: the 3-city study

    PubMed Central

    Carrière, Isabelle; Fourrier-Reglat, Annie; Dartigues, Jean-François; Rouaud, Olivier; Pasquier, Florence; Ritchie, Karen; Ancelin, Marie-Laure

    2009-01-01

    Objective To examine the association between use of medications with anticholinergic properties, cognitive decline and incident dementia in a large community-based sample of subjects aged 65 years and over. Methods Participants were 4128 women and 2784 men from a population-based cohort recruited from three French cities. Cognitive performance, clinical diagnosis of dementia and anticholinergic use were evaluated at base-line, 2 and 4 year later. Results 7.5% of subjects reported anticholinergic drug use at base-line. Multivariate adjusted logistic regression indicated that women reporting anticholinergic drugs at base-line showed greater decline over four years in verbal fluency scores (OR=1.41, CI=1.11–1.79) and in global cognitive functioning (OR=1.22, CI=0.96–1.55) than women not using anticholinergic drugs. In men, an association was found with decline in visual memory (OR=1.63, CI=1.08–2.47) and to a lesser extent in executive function (OR=1.47, CI=0.89–2.44). Significant interactions were observed in women between anticholinergic use and age, apolipoprotein E, or hormone replacement therapy. A significantly 1.4–2 fold higher risk of cognitive decline was observed for continuous anticholinergic users but not for those having discontinued. The risk of incident dementia over the four-year followup was also increased in continuous users (HR=1.65, CI=1.00–2.73) but not in those having discontinued anticholinergic drugs (HR=1.28, CI=0.59–2.76). Conclusions Elderly people taking anticholinergic drugs were at increased risk for cognitive decline and dementia. Discontinuing anticholinergic treatment was associated with a decreased risk. Physicians should carefully consider prescription of anticholinergic drugs in elderly people especially in the oldest old and persons at high genetic risk of cognitive disorder. PMID:19636034

  16. Agricultural change and population growth: a brief survey on the case of China in historical perspective.

    PubMed

    Liu, T

    1986-03-01

    A historical review of the relationship between agricultural change and population growth in China is presented. "This paper will try to discuss four aspects of agricultural change that are related to population growth. They are: (1) expansion of agricultural frontier, (2) changes in cultivation methods and land use, (3) improvements in agricultural technology, and (4) irrigation and water-control. Each of these aspects [is] treated briefly with temporal and spatial perspectives...." The relevance of the Boserup theory that population pressure leads to agricultural development is considered in the Chinese context. It is found that some evidence supports the theory. (summary in CHI)

  17. Population decline of the Elfin-woods Warbler Setophaga angelae in eastern Puerto Rico

    Treesearch

    W.J. Arendt; S.S. Qian; K. Mineard

    2013-01-01

    We estimated the population density of the globally threatened Elfin-woods Warbler Setophaga angelae within two forest types at different elevations in the Luquillo Experimental Forest in north-eastern Puerto Rico. Population densities ranged from 0.01 to 0.02 individuals/ha in elfin woodland and 0.06–0.26 individuals/ha in palo colorado forest in 2006, with average...

  18. King penguin population on Macquarie Island recovers ancient DNA diversity after heavy exploitation in historic times.

    PubMed

    Heupink, Tim H; van den Hoff, John; Lambert, David M

    2012-08-23

    Historically, king penguin populations on Macquarie Island have suffered greatly from human exploitation. Two large colonies on the island were drastically reduced to a single small colony as a result of harvesting for the blubber oil industry. However, recent conservation efforts have resulted in the king penguin population expanding in numbers and range to recolonize previous as well as new sites. Ancient DNA methods were used to estimate past genetic diversity and combined with studies of modern populations, we are now able to compare past levels of variation with extant populations on northern Macquarie Island. The ancient and modern populations are closely related and show a similar level of genetic diversity. These results suggest that the king penguin population has recovered past genetic diversity in just 80 years owing to conservation efforts, despite having seen the brink of extinction.

  19. King penguin population on Macquarie Island recovers ancient DNA diversity after heavy exploitation in historic times

    PubMed Central

    Heupink, Tim H.; van den Hoff, John; Lambert, David M.

    2012-01-01

    Historically, king penguin populations on Macquarie Island have suffered greatly from human exploitation. Two large colonies on the island were drastically reduced to a single small colony as a result of harvesting for the blubber oil industry. However, recent conservation efforts have resulted in the king penguin population expanding in numbers and range to recolonize previous as well as new sites. Ancient DNA methods were used to estimate past genetic diversity and combined with studies of modern populations, we are now able to compare past levels of variation with extant populations on northern Macquarie Island. The ancient and modern populations are closely related and show a similar level of genetic diversity. These results suggest that the king penguin population has recovered past genetic diversity in just 80 years owing to conservation efforts, despite having seen the brink of extinction. PMID:22357937

  20. Diclofenac disposition in Indian cow and goat with reference to Gyps vulture population declines.

    PubMed

    Taggart, M A; Cuthbert, R; Das, D; Sashikumar, C; Pain, D J; Green, R E; Feltrer, Y; Shultz, S; Cunningham, A A; Meharg, A A

    2007-05-01

    Gyps vultures across India are declining rapidly and the NSAID diclofenac has been shown to be the major cause. Vultures scavenge livestock carcasses that have been treated with diclofenac within the days preceding death. We present data on diclofenac disposition in Indian cow and goat, and field data on the prevalence of diclofenac in carcases in the environment. In the disposition experiment, animals were treated with a single intramuscular injection of diclofenac at 1000 microg kg-1 bw. In cow, diclofenac was detectable in liver, kidney and intestine up to 71 h post-treatment; in plasma, half-life was 12.2 h. In goat, tissue residues were undetectable after 26 h. Prevalence of diclofenac in liver from 36 dead livestock collected in the field was 13.9%. Data suggest that diclofenac residues in Indian cow and goat are short-lived, but diclofenac prevalence in carcasses available to vultures may still be very high.

  1. De novo lipogenesis is suppressed during fasting but upregulated at population decline in cyclic voles.

    PubMed

    Nieminen, Petteri; Rouvinen-Watt, Kirsti; Harris, Lora; Huitu, Otso; Henttonen, Heikki; Mustonen, Anne-Mari

    2016-04-01

    Arvicolines are susceptible to the development of fatty liver during short-term fasting. We examined the potential role of de novo lipogenesis (DNL) (i) in the development of fasting-induced fatty liver and (ii) during a population cycle by measuring the mRNA expression of acetyl-CoA carboxylase-1 (ACC1) and fatty acid synthase (FAS). Laboratory voles (Microtus oeconomus and Microtus arvalis) were fed or fasted for 12 or 18 h and their liver mRNA levels were determined. Both species showed decreased mRNA expression of ACC1 and FAS during fasting. This suggests that DNL does not participate in the development of fatty liver in voles, different from human non-alcoholic fatty liver disease. In wild bank voles (Myodes glareolus), the mRNA levels of the genes of interest were higher during the population decline compared to the increase phase. In conclusion, DNL was suppressed during acute fasting but upregulated during a long-term population decline-a period of purported scarcity of high-quality food. © 2016 by the Society for Experimental Biology and Medicine.

  2. Testing mechanisms of Bergmann's rule: phenotypic decline but no genetic change in body size in three passerine bird populations.

    PubMed

    Husby, Arild; Hille, Sabine M; Visser, Marcel E

    2011-08-01

    Bergmann's rule predicts a decrease in body size with increasing temperature and has much empirical support. Surprisingly, we know very little about whether "Bergmann size clines" are due to a genetic response or are a consequence of phenotypic plasticity. Here, we use data on body size (mass and tarsus length) from three long-term (1979-2008) study populations of great tits (Parus major) that experienced a temperature increase to examine mechanisms behind Bergmann's rule. We show that adult body mass decreased over the study period in all populations and that tarsus length increased in one population. Both body mass and tarsus length were heritable and under weak positive directional selection, predicting an increase, rather than a decrease, in body mass. There was no support for microevolutionary change, and thus the observed declines in body mass were likely a result of phenotypic plasticity. Interestingly, this plasticity was not in direct response to temperature changes but seemed to be due to changes in prey dynamics. Our results caution against interpreting recent phenotypic body size declines as adaptive evolutionary responses to temperature changes and highlight the importance of considering alternative environmental factors when testing size clines.

  3. Historical analysis of genetic variation reveals low effective population size in a northern pike (Esox lucius) population.

    PubMed

    Miller, L M; Kapuscinski, A R

    1997-11-01

    Effective population size (Ne) of a natural fish population was estimated from temporal changes in allele frequencies at seven microsatellite loci. Use of a historical collection of fish scales made it possible to increase the precision of estimates by increasing the time interval between samples and to use an equation developed for discrete generations without correcting for demographic parameters. Estimates of Ne for the time intervals 1961-1977 and 1977-1993 were 35 and 72, respectively. For the entire interval, 1961-1993, the estimate of Ne was 48 when based on a weighted mean derived from the above two estimates or 125 when calculated from 1961 and 1993 samples only. Corresponding ratios of effective size to adult census size ranged from 0.03 to 0.14. An Ne of 48 over a 32-year period would imply that this population lost as much as 8% of its heterozygosity in that time. Results suggest the potential for using genetic methods based on microsatellite loci data to compare historical trends in Ne with population dynamic parameters. Such comparisons will help to evaluate the relationship between genetic diversity and long-term persistence of natural populations.

  4. Historical Analysis of Genetic Variation Reveals Low Effective Population Size in a Northern Pike (Esox Lucius) Population

    PubMed Central

    Miller, L. M.; Kapuscinski, A. R.

    1997-01-01

    Effective population size (N(e)) of a natural fish population was estimated from temporal changes in allele frequencies at seven microsatellite loci. Use of a historical collection of fish scales made it possible to increase the precision of estimates by increasing the time interval between samples and to use an equation developed for discrete generations without correcting for demographic parameters. Estimates of N(e) for the time intervals 1961-1977 and 1977-1993 were 35 and 72, respectively. For the entire interval, 1961-1993, the estimate of N(e) was 48 when based on a weighted mean derived from the above two estimates or 125 when calculated from 1961 and 1993 samples only. Corresponding ratios of effective size to adult census size ranged from 0.03 to 0.14. An N(e) of 48 over a 32-year period would imply that this population lost as much as 8% of its heterozygosity in that time. Results suggest the potential for using genetic methods based on microsatellite loci data to compare historical trends in N(e) with population dynamic parameters. Such comparisons will help to evaluate the relationship between genetic diversity and long-term persistence of natural populations. PMID:9383067

  5. Historical and Contemporary Patterns of Mercury in a Hydroelectric Reservoir and Downstream Fishery: Concentration Decline in Water and Fishes.

    PubMed

    Green, Derek J; Duffy, Mark; Janz, David M; McCullum, Kevin; Carrière, Gary; Jardine, Timothy D

    2016-08-01

    Mercury (Hg) contamination can pose risks to human and animal health as well as commercial fisheries. Reservoir construction in riverine systems produces flooded conditions amenable to Hg(II)-methylating bacteria, which can transform this relatively benign environmental contaminant into the bioaccumulative, environmentally relevant, and neurotoxic methyl-Hg (MeHg). Hg concentrations ([Hg]) in fishes from reservoirs can take decades to decrease to pre-dam levels, but less is known about Hg exported downstream and its dynamics within downstream fish populations. We examined and compared the multidecadal rates of biotic [Hg] decrease and contemporary factors affecting [Hg] in fish collected from a hydroelectric reservoir (Tobin Lake) and a related downstream fishery (Cumberland Lake) along the Saskatchewan River, Canada. Rates of [Hg] decrease were considered in four species-northern pike (Esox lucius), sauger (Sander canadensis), goldeye (Hiodon alosoides), and walleye (S. vitreus)-all of which showed a significant decrease over time (p < 0.001) and are now lower than Health Canada consumption guidelines (0.5 μg/g). Rates of decrease ranged from 0.5 to 3.9 %/year and were similar between sites in the cases of northern pike and sauger. Contemporary factors affecting [Hg] in walleye collected downstream include fish length (p < 0.001), fish age (p < 0.001), and trophic magnification through the food web (p < 0.001), and relationships between [Hg] and trophic level in predatory and prey fish are now similar to those found in non-Hg-inundated systems at a similar latitude. Together, these results suggest connected contamination between the two sites and delineate the timeline during which [Hg] in a variety of fish species decreased to nontoxic levels in both locations.

  6. Modeling predicts that redd trampling by cattle may contribute to population declines of native trout.

    PubMed

    Peterson, Douglas P; Rieman, Bruce E; Young, Michael K; Brammer, James A

    2010-06-01

    Unrestricted livestock grazing can degrade aquatic ecosystems, and its effects on native vertebrate species are generally mediated by changes to physical habitat. Recently, high estimated rates of cattle trampling on artificial redds within federal grazing allotments in southwestern Montana, USA, has raised concern that direct mortality from trampling may contribute to imperilment of native westslope cutthroat trout (Oncorhynchus clarkii lewisi). To explore the implications of cattle trampling, we built two mathematical models. First we used a temperature-driven model of egg-to-fry mortality representative of the developmental stages during which embryos would be vulnerable to trampling. Cattle trampling was an additional source of mortality (beyond natural mortality), and we modeled egg-to-fry mortality across a range of trampling rates (25-125% per month) for scenarios assuming low (0.60), moderate (0.81), and high (0.95) natural mortality. We then used a matrix model to determine how trampling affected population growth (lambda), assuming initially stable (lambda = 1.008) or slow-growing populations (lambda = 1.025 and 1.05). Cattle trampling concentrated over a few days when the embryos were most sensitive caused greater egg-to-fry mortality than when the same amount of trampling occurred over one month. Trampling caused a large increase in egg-to-fry mortality when that natural mortality was low, but the overall population-level effect was far less than might have been anticipated from the rate of trampling itself. Nonetheless, small reductions in population growth rate could be biologically significant for populations with little or no demographic resilience, and trampling rates as low as 25% could lead to negative population growth. The rapid reduction in resilience with increased trampling rates (>50%) means that even growing populations are less likely to recover from periodic fluctuations. The overall risk posed by trampling will depend on whether

  7. Association of Delirium With Cognitive Decline in Late Life: A Neuropathologic Study of 3 Population-Based Cohort Studies.

    PubMed

    Davis, Daniel H J; Muniz-Terrera, Graciela; Keage, Hannah A D; Stephan, Blossom C M; Fleming, Jane; Ince, Paul G; Matthews, Fiona E; Cunningham, Colm; Ely, E Wesley; MacLullich, Alasdair M J; Brayne, Carol

    2017-03-01

    Delirium is associated with accelerated cognitive decline. The pathologic substrates of this association are not yet known, that is, whether they are the same as those associated with dementia, are independent, or are interrelated. To examine whether the accelerated cognitive decline observed after delirium is independent of the pathologic processes of classic dementia. Harmonized data from 987 individual brain donors from 3 observational cohort studies with population-based sampling (Vantaa 85+, Cambridge City Over-75s Cohort, Cognitive Function and Ageing Study) performed from January 1, 1985, through December 31, 2011, with a median follow-up of 5.2 years until death, were used in this study. Neuropathologic assessments were performed with investigators masked to clinical data. Data analysis was performed from January 1, 2012, through December 31, 2013. Clinical characteristics of brain donors were not different from the rest of the cohort. Outcome ascertainment was complete given that the participants were brain donors. Delirium (never vs ever) and pathologic burden of neurofibrillary tangles, amyloid plaques, vascular lesions, and Lewy bodies. Effects modeled using random-effects linear regression and interactions between delirium and pathologic burden were assessed. Change in Mini-Mental State Examination (MMSE) scores during the 6 years before death. There were 987 participants (290 from Vantaa 85+, 241 from the Cambridge City Over-75s Cohort, and 456 from the Cognitive Function and Ageing Study) with neuropathologic data; mean (SD) age at death was 90 (6.4) years, including 682 women (69%). The mean MMSE score 6 years before death was 24.7 points. The 279 individuals with delirium (75% women) had worse initial scores (-2.8 points; 95% CI, -4.5 to -1.0; P < .001). Cognitive decline attributable to delirium was -0.37 MMSE points per year (95% CI, -0.60 to -0.13; P < .001). Decline attributable to the pathologic processes of dementia was -0.39 MMSE

  8. Decline in a Tilletia indica teliospore population in a naturally infested Arizona (USA) wheat field

    USDA-ARS?s Scientific Manuscript database

    Following a 2004-outbreak of Karnal bunt in an Arizona wheat field where infection had not been detected in recent years, the population and viability of Tilletia indica teliospores in surface and subsurface layers of soil were monitored over a four-year period. The field was seeded with two paralle...

  9. CATASTROPHIC DECLINE OF A HIGH-DENSITY POPULATION OF COTTON RATS (SIGMODIN HISPIDUS) IN CENTRAL OKLAHOMA

    EPA Science Inventory

    Along the northern periphery of their range, populations of the hispid cotton rat, Sigmodon hispidus, are vulnerable to major reductions in density and occasional local extinctions as a result of severe winter weather. Between our sampling periods on 3 December 2000 and 14 Januar...

  10. Recent Evolution in Rattus norvegicus Is Shaped by Declining Effective Population Size.

    PubMed

    Deinum, Eva E; Halligan, Daniel L; Ness, Rob W; Zhang, Yao-Hua; Cong, Lin; Zhang, Jian-Xu; Keightley, Peter D

    2015-10-01

    The brown rat, Rattus norvegicus, is both a notorious pest and a frequently used model in biomedical research. By analyzing genome sequences of 12 wild-caught brown rats from their presumed ancestral range in NE China, along with the sequence of a black rat, Rattus rattus, we investigate the selective and demographic forces shaping variation in the genome. We estimate that the recent effective population size (Ne) of this species = [Formula: see text], based on silent site diversity. We compare patterns of diversity in these genomes with patterns in multiple genome sequences of the house mouse (Mus musculus castaneus), which has a much larger Ne. This reveals an important role for variation in the strength of genetic drift in mammalian genome evolution. By a Pairwise Sequentially Markovian Coalescent analysis of demographic history, we infer that there has been a recent population size bottleneck in wild rats, which we date to approximately 20,000 years ago. Consistent with this, wild rat populations have experienced an increased flux of mildly deleterious mutations, which segregate at higher frequencies in protein-coding genes and conserved noncoding elements. This leads to negative estimates of the rate of adaptive evolution (α) in proteins and conserved noncoding elements, a result which we discuss in relation to the strongly positive estimates observed in wild house mice. As a consequence of the population bottleneck, wild rats also show a markedly slower decay of linkage disequilibrium with physical distance than wild house mice.

  11. CATASTROPHIC DECLINE OF A HIGH-DENSITY POPULATION OF COTTON RATS (SIGMODIN HISPIDUS) IN CENTRAL OKLAHOMA

    EPA Science Inventory

    Along the northern periphery of their range, populations of the hispid cotton rat, Sigmodon hispidus, are vulnerable to major reductions in density and occasional local extinctions as a result of severe winter weather. Between our sampling periods on 3 December 2000 and 14 Januar...

  12. Declines in the breeding population of Vaux's Swifts in northeastern Oregon.

    Treesearch

    Evelyn L. Bull

    2003-01-01

    I investigated trends in the breeding population of Vaux's Swift (Chaetura vauxi) in northeastern Oregon by revisiting in 2003 39 stands of trees that contained swifts in 1991. In 2003 the number of swifts in these stands was significantly fewer, with only 46% of the stands still containing swifts. Only 29% of the 58 nest and roost trees the...

  13. RENO, NV, JANUARY 15, 2004: FACTORS IMPLICATED IN AMPHIBIAN POPULATION DECLINES IN THE UNITED STATES

    EPA Science Inventory

    Factors known or suspected to be adversely affecting native amphibian populations in the US were identified using information from 267 species accounts written in a standardized format by multiple authors in the forthcoming book, 'Status and Conservation of U.S. Amphibians'. Spec...

  14. Historical intake and elimination of polychlorinated biphenyls and organochlorine pesticides by the Australian population reconstructed from biomonitoring data.

    PubMed

    Bu, Qingwei; MacLeod, Matthew; Wong, Fiona; Toms, Leisa-Maree L; Mueller, Jochen F; Yu, Gang

    2015-01-01

    Quantifying the competing rates of intake and elimination of persistent organic pollutants (POPs) in the human body is necessary to understand the levels and trends of POPs at a population level. In this paper we reconstruct the historical intake and elimination of ten polychlorinated biphenyls (PCBs) and five organochlorine pesticides (OCPs) from Australian biomonitoring data by fitting a population-level pharmacokinetic (PK) model. Our analysis exploits two sets of cross-sectional biomonitoring data for PCBs and OCPs in pooled blood serum samples from the Australian population that were collected in 2003 and 2009. The modeled adult reference intakes in 1975 for PCB congeners ranged from 0.89 to 24.5ng/kgbw/day, lower than the daily intakes of OCPs ranging from 73 to 970ng/kgbw/day. Modeled intake rates are declining with half-times from 1.1 to 1.3years for PCB congeners and 0.83 to 0.97years for OCPs. The shortest modeled intrinsic human elimination half-life among the compounds studied here is 6.4years for hexachlorobenzene, and the longest is 30years for PCB-74. Our results indicate that it is feasible to reconstruct intakes and to estimate intrinsic human elimination half-lives using the population-level PK model and biomonitoring data only. Our modeled intrinsic human elimination half-lives are in good agreement with values from a similar study carried out for the population of the United Kingdom, and are generally longer than reported values from other industrialized countries in the Northern Hemisphere.

  15. Decline of tuberculosis mortality in an urban Mexican-origin population, 1935-1984.

    PubMed

    Bradshaw, B S; Smith, D P

    1997-01-01

    Through a series of life table analyses, this paper describes the natural history of tuberculosis mortality in a Mexican-origin community over five decades (1935-84) during which the disease underwent a transition from a major underlying cause of death to a disease conditioned mentioned more often on death certificates as contributing to death than causing death. The decline in death rates from 1940 to 1950 was especially remarkable. Successive birth cohorts of Mexican Americans, separated by as little as five years of age, experienced distinctly lower risk of death from tuberculosis as they entered young adulthood. There was a rapid convergence in age-specific patterns of tuberculosis death rates in Mexican Americans toward those of non-Hispanic whites, so that by 1960 tuberculosis was primarily a cause of death in old age rather than young adulthood. The impact of changing environment, both through improvements of conditions within neighborhoods and through residential mobility, on birth cohorts at risk of tuberculosis needs to be examined in further research.

  16. Stocking impact and temporal stability of genetic composition in a brackish northern pike population (Esox lucius L.), assessed using microsatellite DNA analysis of historical and contemporary samples.

    PubMed

    Larsen, P F; Hansen, M M; Nielsen, E E; Jensen, L F; Loeschcke, V

    2005-08-01

    During the last decade, brackish northern pike populations in Denmark have been subject to stocking programmes, using nonindigenous pike from freshwater lakes, in order to compensate for drastic population declines. The present study was designed to investigate the genetic impact of stocking freshwater pike into a brackish pike population in Stege Nor, Denmark. We analysed polymorphism at eight microsatellite loci in samples representing the indigenous Stege Nor population prior to stocking (ie from 1956 to 1957), along with a sample of the contemporary Stege Nor population and samples from the three populations used for stocking. Despite large numbers of stocked fry, the results from both individual and population level admixture analyses demonstrated extremely poor performance and <1% introgression of stocked freshwater pike into the brackish pike population. Furthermore, pairwise F(ST) estimates between samples demonstrated close genetic relationship among temporal samples from Stege Nor, indicating temporal stability over the last 45 years. We also estimated the effective population size (N(e)) of pike in Stege Nor and applied a test for recent population bottlenecks. The harmonic mean of N(e) was relatively high (>250), but there were indications of bottlenecks in all samples and populations. We ascribe this finding to historical rather than recent bottlenecks, possibly dating back to founder events associated with postglacial recolonisation.

  17. Historical contingency affects signaling strategies and competitive abilities in evolving populations of simulated robots.

    PubMed

    Wischmann, Steffen; Floreano, Dario; Keller, Laurent

    2012-01-17

    One of the key innovations during the evolution of life on earth has been the emergence of efficient communication systems, yet little is known about the causes and consequences of the great diversity within and between species. By conducting experimental evolution in 20 independently evolving populations of cooperatively foraging simulated robots, we found that historical contingency in the occurrence order of novel phenotypic traits resulted in the emergence of two distinct communication strategies. The more complex foraging strategy was less efficient than the simpler strategy. However, when the 20 populations were placed in competition with each other, the populations with the more complex strategy outperformed the populations with the less complex strategy. These results demonstrate a tradeoff between communication efficiency and robustness and suggest that stochastic events have important effects on signal evolution and the outcome of competition between distinct populations.

  18. Validity of the IQCODE-CA: An informant questionnaire on cognitive decline modified for a cardiac arrest population.

    PubMed

    Blennow Nordström, Erik; Lilja, Gisela; Årestedt, Kristofer; Friberg, Hans; Nielsen, Niklas; Vestberg, Susanna; Cronberg, Tobias

    2017-09-01

    To examine the psychometric properties of a modified version of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE), for a cardiac arrest population (IQCODE-CA). The IQCODE-CA, a 26-item observer-reported questionnaire, was completed by informants, defined as relatives or close friends, of 268 out-of-hospital cardiac arrest (OHCA) survivors who participated in the Target Temperature Management trial in a scheduled follow-up 180±14days after OHCA. Survivors completed the Mini Mental State Examination (MMSE), the Rivermead Behavioural Memory Test (RBMT) and the Hospital Anxiety and Depression Scale (HADS). An exploratory factor analysis was performed. Associations between IQCODE-CA results and demographic variables along with other instruments were calculated. Area under the curve (AUC) ratios were evaluated to examine discrimination. The IQCODE-CA measured one factor, global cognitive decline, with high internal consistency (ordinal α=0.95). Age, gender or education did not influence the IQCODE-CA score. Associations with performance-based measures of global cognitive function as well as anxiety and depression ranged from small to moderate (rs=-0.29 to 0.38). AUC ratios ranged from fair to good (0.72-0.81). According to the MMSE and RBMT, the optimal cut-off score to identify cognitive decline on the IQCODE-CA was 3.04. Using this value, 53% of the survivors were under the cut-off. The IQCODE-CA identified a large amount of survivors with possible cognitive problems, making it useful when screening for cognitive decline post-CA. Due to lower AUC ratios than desired, additional performance-based measures should be used to improve the overall screening methodology. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Evolutionary consequences of historical metal contamination for natural populations of Chironomus riparius (Diptera: Chironomidae).

    PubMed

    Pedrosa, João; Campos, Diana; Cocchiararo, Berardino; Nowak, Carsten; Soares, Amadeu M V M; Barata, Carlos; L T Pestana, João

    2017-05-01

    Populations inhabiting metal-impacted freshwater systems located nearby industrial and urban areas may be under intense selection. The present study aims to address two fundamental microevolutionary aspects of metal contamination in the midge Chironomus riparius (Meigen): Are populations inhabiting historically metal contaminated sites genetically adapted to metals? And, are populations from these sites genetically eroded? To answer these questions, C. riparius populations were sampled from three sites with well-known histories of metal contamination and three nearby-located references. Genetic adaptation to metals was investigated through acute and chronic exposures to cadmium (Cd), after rearing all populations for at least six generations under laboratory clean conditions. Genetic diversity was estimated based on the allelic variation of seven microsatellite markers. Results showed higher acute tolerance to Cd in populations originating from metal contaminated sites compared to their respective references and significant differences in two out of three pairwise comparisons. However, there was a mismatch between acute and chronic tolerance to Cd with results of the partial life-cycle tests suggesting fitness costs under control clean conditions in two metal-adapted populations. Despite no evidences of genetic erosion in populations sampled from metal contaminated sites, our results suggest genetically inherited tolerance to Cd in populations inhabiting historically contaminated sites. These findings lend support to the use of C. riparius as a model organism in evolutionary toxicology and highlight the importance of coupling measures of neutral genetic diversity with assessments of chemical tolerance of populations for a better understanding of contaminant-induced adaptation and evolutionary processes.

  20. Genetic structure of introduced populations: 120-year-old DNA footprint of historic introduction in an insular small mammal population

    PubMed Central

    Simpson, Siobhan; Blampied, Nick; Peniche, Gabriela; Dozières, Anne; Blackett, Tiffany; Coleman, Stephen; Cornish, Nina; Groombridge, Jim J

    2013-01-01

    Wildlife populations have been introduced to new areas by people for centuries, but this human-mediated movement can disrupt natural patterns of genetic structure by altering patterns of gene flow. Insular populations are particularly prone to these influences due to limited opportunities for natural dispersal onto islands. Consequently, understanding how genetic patterns develop in island populations is important, particularly given that islands are frequently havens for protected wildlife. We examined the evolutionary origins and extent of genetic structure within the introduced island population of red squirrels (Sciurus vulgaris) on the Channel Island of Jersey using mitochondrial DNA (mtDNA) control region sequence and nuclear microsatellite genotypes. Our findings reveal two different genetic origins and a genetic architecture reflective of the introductions 120 years ago. Genetic structure is marked within the maternally inherited mtDNA, indicating slow dispersal of female squirrels. However, nuclear markers detected only weak genetic structure, indicating substantially greater male dispersal. Data from both mitochondrial and nuclear markers support historic records that squirrels from England were introduced to the west of the island and those from mainland Europe to the east. Although some level of dispersal and introgression across the island between the two introductions is evident, there has not yet been sufficient gene flow to erase this historic genetic “footprint.” We also investigated if inbreeding has contributed to high observed levels of disease, but found no association. Genetic footprints of introductions can persist for considerable periods of time and beyond traditional timeframes of wildlife management. PMID:23532702

  1. Multilocus sequence typing provides insights into the population structure and evolutionary potential of Brenneria goodwinii, associated with acute oak decline.

    PubMed

    Kaczmarek, Maciej; Mullett, Martin S; McDonald, James E; Denman, Sandra

    2017-01-01

    Brenneria goodwinii is one of the most frequently isolated Gram-negative bacteria from native oak species, Quercus robur and Q. petraea, affected by acute oak decline (AOD) in the UK. We investigated the population biology of this bacterial species using a multilocus sequence analysis to determine the population structure and evolutionary potential. Seven partial housekeeping genes were used in the analyses. Amongst 44 bacterial strains from seven different locations, we identified 22 unique sequence types [STs]; only one ST was found at two separate locations. Phylogenetic and cluster-based analyses suggested that B. goodwinii STs form two main distinct groups; however, no geographical pattern of their distribution could be observed. Clonality and recombination tests demonstrated that the studied population is primarily clonal, however both mutation and recombination processes play a role in shaping the genetic structure and evolution of the population. Our study suggests that the B. goodwinii population on oak in the UK has an endemic form, with background recombination appearing to generate new alleles more frequently than mutation, despite the introduction of nucleotide substitutions being approximately twice less likely than mutation. The newly emerged STs subsequently undergo clonal expansion to become dominant genotypes within their specific geographical locations and even within the individual host oak trees.

  2. Mixing plants from different origins to restore a declining population: ecological outcomes and local perceptions 10 years later.

    PubMed

    Maurice, Anne-Claire; Abdelkrim, Jawad; Cisel, Matthieu; Zavodna, Monika; Bardin, Philippe; Matamoro, Alexis; Dumez, Richard; Machon, Nathalie

    2013-01-01

    Populations of the Large-flowered Sandwort (Arenaria grandiflora L.) in the Fontainebleau forest (France) have declined rapidly during the last century. Despite the initiation of a protection program in 1991, less than twenty individuals remained by the late 1990s. The low fitness of these last plants, which is likely associated with genetic disorders and inbreeding depression, highlighted the need for the introduction of non-local genetic material to increase genetic diversity and thus restore Fontainebleau populations. Consequently, A. grandiflora was introduced at three distant sites in the Fontainebleau forest in 1999. Each of these populations was composed of an identical mix of individuals of both local and non-local origin that were obtained through in vitro multiplication. After establishment, the population status (number of individuals, diameter of the plants, and number of flowers) of the introduced populations was monitored. At present, two populations (one of which is much larger than the other) persist, while the third one became extinct in 2004. Analyses of the ecological parameters of the introduction sites indicated that differences in soil pH and moisture might have contributed to the differences in population dynamics. This introduction plan and its outcome attracted interest of local community, with those who supported the plan and regarded its 10-year result as a biological success (i.e., persistent populations were created), but also those who expressed reservations or disapproval of the plan and its outcome. To understand this controversy, a sociological study involving 27 semi-structured interviews was carried out. From these interviews emerged three areas of controversy: alteration of the identity of the plant, alteration of the identity of its territory, and the biological and ethical consequences of the techniques used for the experimental conservation.

  3. Mixing Plants from Different Origins to Restore a Declining Population: Ecological Outcomes and Local Perceptions 10 Years Later

    PubMed Central

    Maurice, Anne-Claire; Abdelkrim, Jawad; Cisel, Matthieu; Zavodna, Monika; Bardin, Philippe; Matamoro, Alexis; Dumez, Richard; Machon, Nathalie

    2013-01-01

    Populations of the Large-flowered Sandwort (Arenaria grandiflora L.) in the Fontainebleau forest (France) have declined rapidly during the last century. Despite the initiation of a protection program in 1991, less than twenty individuals remained by the late 1990s. The low fitness of these last plants, which is likely associated with genetic disorders and inbreeding depression, highlighted the need for the introduction of non-local genetic material to increase genetic diversity and thus restore Fontainebleau populations. Consequently, A. grandiflora was introduced at three distant sites in the Fontainebleau forest in 1999. Each of these populations was composed of an identical mix of individuals of both local and non-local origin that were obtained through in vitro multiplication. After establishment, the population status (number of individuals, diameter of the plants, and number of flowers) of the introduced populations was monitored. At present, two populations (one of which is much larger than the other) persist, while the third one became extinct in 2004. Analyses of the ecological parameters of the introduction sites indicated that differences in soil pH and moisture might have contributed to the differences in population dynamics. This introduction plan and its outcome attracted interest of local community, with those who supported the plan and regarded its 10-year result as a biological success (i.e., persistent populations were created), but also those who expressed reservations or disapproval of the plan and its outcome. To understand this controversy, a sociological study involving 27 semi-structured interviews was carried out. From these interviews emerged three areas of controversy: alteration of the identity of the plant, alteration of the identity of its territory, and the biological and ethical consequences of the techniques used for the experimental conservation. PMID:23349668

  4. Contaminants in eggs of western snowy plovers and California least terns: is there a link to population decline?

    USGS Publications Warehouse

    Hothern, R.L.; Powell, A.N.

    2000-01-01

    Environmental contaminants may have adverse effects on avian reproduction and may be contributing to declines of avian species nesting along the southern California Coast. Examples of impaired reproduction caused by organochlorine pesticides, PCBs, and elements such as mercury (Hg) and selenium (Se) include delayed ovulation, reduced egg production, defective eggshells, decreased hatchability, embryotoxicosis, aberrant incubation behavior, and mortality of chicks and adults (Heinz 1976; Blus 1982; Ohlendorf et al. 1986).The federal government listed the California least tern (Sterna antillarum browni) as endangered in 1970 (U.S. Fish and Wildlife Service 1985). The Pacific Coast population of western snowy plover (Charadrius alexandrinus nivosus) was listed as threatened by the federal government in 1993 (Federal Register 1993). Habitat loss and human-related disturbance have been identified as primary causes of the decline of both the primarily insectivorous plover (Powell 1998) and the primarily piscivorous tern, but local food shortages have also limited the terns.Both species breed along the highly urbanized coastline of southern California. A portion of the snowy plover population is present on the breeding grounds yearround, while the remainder winters along the Pacific Coast south into Baja California, Mexico (Stenzel et al. 1994). Least terns winter primarily along the Pacific Coast of Central America (Massey et al. 1992). This study was designed to evaluate the effects that contaminants acquired on the breeding or wintering grounds might be having on reproduction by snowy plovers and least terns.

  5. Historical sketch of Slovak Haban (Hutterite) population based on autosomal STR analysis.

    PubMed

    Soták, M; Petrejčíková, E; Siváková, D; Rębała, K; Bôžiková, A; Bernasovský, I; Carnogurská, J; Boronová, I; Mačeková, S; Homol'ová, L; Sovičová, A; Gabriková, D; Rusínová, L; Bernasovská, J

    2011-10-01

    According to the Hutterite chronicles, the Habans arrived from Austrian Tyrol, Switzerland, and northernmost Italy and stayed in four regions of Slovakia (Sobotište, Vel'ké Leváre, Moravský Svätý Ján, Trenčín). There are some communities in western Slovakia that retained their Haban cultural identity and still identify themselves as descendents of the Hutterite population with their own specific customs. Slovak Habans are typical founder population with significant social isolation for which high degree of inbreeding is typical. Present study investigated STR polymorphisms as a powerful genetic tool for population genetic studies. The aim was to perform a comparative, population genetic study based on 15 STR loci widely used in forensic genetics, of the Haban population, the Slovak majority population and the population of Tyrol. We analyzed allele frequencies and other statistical parameters in three selected populations in order to identify groups of specific ethnic origin and establish their genetic relationship. The data set included 110 unrelated Habans and 201 unrelated individuals from the Slovak majority population, as well as allelic frequencies for the population of Austrian Tyrol available in the literature. Population pairwise FST values used as a short term genetic distance between populations showed significant differentiation between the Habans and both reference populations (FST=0.0025 and 0.0042 for comparison with the Slovaks and Austrians, respectively; p<10(-3)). The Slovak Hutterites were demonstrated to be genetically distinct and more closely related to their geographic neighbors than to their historical ancestral population, which may be at least partially explained by gene flow between neighboring Haban and Slovak populations.

  6. Declining hepatitis A seroprevalence in adults in Catalonia (Spain): a population-based study

    PubMed Central

    Domínguez, Àngela; Bruguera, Miquel; Plans, Pere; Espuñes, Jordi; Costa, Josep; Plasencia, Antoni; Salleras, Lluis

    2007-01-01

    Background One of the main uses of seroprevalence studies it to evaluate vaccination programmes. In 1998, a programme of universal vaccination of preadolescents in schools with the hepatitis A vaccine was begun in Catalonia. The objective of this study was to investigate the prevalence and risk factors of hepatitis A virus infection (HAV) in a sample of the adult population of Catalonia in 2002 and to evaluate the changes with respect to a survey carried out in 1996. Methods The prevalence of HAV antibodies was determined by a third generation competitive immunometric assay in a representative sample of 1292 people aged >15 years. The association between the prevalence and different sociodemographic variables was determined by multiple logistic regression analysis. Results The standardized global prevalence of HAV antibodies in 2002 was 68.2%, increased with age (p < 0.0001) and was associated with being born outside Catalonia (OR: 1.75; 95% CI 1.11–2.76) and lower social class (OR: 1.14; 95% CI 1.05–1.25). Compared with the last survey carried out in 1996 the standardized global prevalence was lower (68.2% vs 77.8%; p < 0.0001) as was the prevalence in people under 45 years. Conclusion The prevalence of the hepatitis A virus is decreasing in the adult population of Catalonia, especially in the younger age groups. The programme of vaccination of adolescents begun in 1998 to control the disease can provide indirect protection to the unvaccinated population. PMID:17610736

  7. Understanding and Predicting the Fitness Decline of Shrunk Populations: Inbreeding, Purging, Mutation, and Standard Selection

    PubMed Central

    García-Dorado, Aurora

    2012-01-01

    The joint consequences of inbreeding, natural selection, and deleterious mutation on mean fitness after population shrinkage are of great importance in evolution and can be critical to the conservation of endangered populations. I present simple analytical equations that predict these consequences, improving and extending a previous heuristic treatment. Purge is defined as the “extra” selection induced by inbreeding, due to the “extra” fitness disadvantage (2d) of homozygotes for (partially) recessive deleterious alleles. Its effect is accounted for by using, instead of the classical inbreeding coefficient f, a purged inbreeding coefficient g that is weighed by the reduction of the frequency of deleterious alleles caused by purging. When the effective size of a large population is reduced to a smaller stable value N (with Nd ≥ 1), the purged inbreeding coefficient after t generations can be predicted as gt ≈ [(1 – 1/2N) gt-1 + 1/2N](1 – 2d ft-1), showing how purging acts upon previously accumulated inbreeding and how its efficiency increases with N. This implies an early fitness decay, followed by some recovery. During this process, the inbreeding depression rate shifts from its ancestral value (δ) to that of the mutation–selection–drift balance corresponding to N (δ*), and standard selection cancels out the inbreeding depression ascribed to δ*. Therefore, purge and inbreeding operate only upon the remaining δ − δ*. The method is applied to the conservation strategy in which family contributions to the breeding pool are equal and is extended to make use of genealogical information. All these predictions are checked using computer simulation. PMID:22298709

  8. Understanding and predicting the fitness decline of shrunk populations: inbreeding, purging, mutation, and standard selection.

    PubMed

    García-Dorado, Aurora

    2012-04-01

    The joint consequences of inbreeding, natural selection, and deleterious mutation on mean fitness after population shrinkage are of great importance in evolution and can be critical to the conservation of endangered populations. I present simple analytical equations that predict these consequences, improving and extending a previous heuristic treatment. Purge is defined as the "extra" selection induced by inbreeding, due to the "extra" fitness disadvantage (2d) of homozygotes for (partially) recessive deleterious alleles. Its effect is accounted for by using, instead of the classical inbreeding coefficient f, a purged inbreeding coefficient g that is weighed by the reduction of the frequency of deleterious alleles caused by purging. When the effective size of a large population is reduced to a smaller stable value N (with Nd ≥ 1), the purged inbreeding coefficient after t generations can be predicted as g(t) ≈ [(1 - 1/2N) g(t)(-1) + 1/2N](1 - 2d f(t)(-1)), showing how purging acts upon previously accumulated inbreeding and how its efficiency increases with N. This implies an early fitness decay, followed by some recovery. During this process, the inbreeding depression rate shifts from its ancestral value (δ) to that of the mutation-selection-drift balance corresponding to N (δ*), and standard selection cancels out the inbreeding depression ascribed to δ*. Therefore, purge and inbreeding operate only upon the remaining δ - δ*. The method is applied to the conservation strategy in which family contributions to the breeding pool are equal and is extended to make use of genealogical information. All these predictions are checked using computer simulation.

  9. Can Citizen Science Assist in Determining Koala (Phascolarctos cinereus) Presence in a Declining Population?

    PubMed Central

    Flower, Emily; Jones, Darryl; Bernede, Lilia

    2016-01-01

    Simple Summary Current scientific methods used to determine national population estimates for species like the koala, where individuals are scattered over a vast area, have failed to deliver an accurate and widely accepted result. Current citizen science projects aimed at mapping koala sightings reported by the public all use different methods and store their data in their own databases, each collecting scattered pieces of a much larger puzzle. To bring these pieces together, this study developed guidelines for a national citizen science project highlighting the importance of using one single method for data collection, and in turn assisting in the development of a national koala population database. Abstract The acceptance and application of citizen science has risen over the last 10 years, with this rise likely attributed to an increase in public awareness surrounding anthropogenic impacts affecting urban ecosystems. Citizen science projects have the potential to expand upon data collected by specialist researchers as they are able to gain access to previously unattainable information, consequently increasing the likelihood of an effective management program. The primary objective of this research was to develop guidelines for a successful regional-scale citizen science project following a critical analysis of 12 existing citizen science case studies. Secondly, the effectiveness of these guidelines was measured through the implementation of a citizen science project, Koala Quest, for the purpose of estimating the presence of koalas in a fragmented landscape. Consequently, this research aimed to determine whether citizen-collected data can augment traditional science research methods, by comparing and contrasting the abundance of koala sightings gathered by citizen scientists and professional researchers. Based upon the guidelines developed, Koala Quest methodologies were designed, the study conducted, and the efficacy of the project assessed. To combat the high

  10. Parapoxvirus causes a deleterious disease in red squirrels associated with UK population declines.

    PubMed Central

    Tompkins, Daniel M; Sainsbury, A W; Nettleton, P; Buxton, D; Gurnell, J

    2002-01-01

    The disease implications of novel pathogens need to be considered when investigating the ecological impact of species translocations on native fauna. Traditional explanations based on competition or predation may often not be the whole story. Evidence suggests that an emerging infectious disease, caused by a parapoxvirus, may be a significant component of the impact that the introduced grey squirrel has had on UK red squirrel populations. Here we validate the potential role of parapoxvirus by proving that the virus is highly pathogenic in the red squirrel while having no detectable effect on grey squirrel health. PMID:11886647

  11. New method of estimating inbreeding in large semi-isolated populations with application to historic Britain.

    PubMed

    Pattison, J E

    2001-01-01

    The purpose of this paper is to introduce a new method of estimating inbreeding in large, relatively isolated, populations over historic times, to demonstrate its application, and indicate some of its limitations and future developments. The method is based on the "paradox" of genealogy, and requires only that the variation of the population size be known, at least reasonably well, over an extended historic period. In this study a method has been developed to model this "paradox" which allows an estimation of the minimum level of inbreeding necessary for a given population curve in terms of values of Pearl's coefficients for each generation. As an example, the method is applied to the population of Britain. It is found that the frequency of siblings occurring in the same generation of a pedigree varies with the population size according to the Fermi-Dirac equation of statistical physics. The effect of introducing a single known estimate of inbreeding into the model is to make the otherwise diverse results for both the actual numbers of ancestors in a generation and the corresponding coefficients of inbreeding to converge.

  12. Can Citizen Science Assist in Determining Koala (Phascolarctos cinereus) Presence in a Declining Population?

    PubMed

    Flower, Emily; Jones, Darryl; Bernede, Lilia

    2016-07-14

    The acceptance and application of citizen science has risen over the last 10 years, with this rise likely attributed to an increase in public awareness surrounding anthropogenic impacts affecting urban ecosystems. Citizen science projects have the potential to expand upon data collected by specialist researchers as they are able to gain access to previously unattainable information, consequently increasing the likelihood of an effective management program. The primary objective of this research was to develop guidelines for a successful regional-scale citizen science project following a critical analysis of 12 existing citizen science case studies. Secondly, the effectiveness of these guidelines was measured through the implementation of a citizen science project, Koala Quest, for the purpose of estimating the presence of koalas in a fragmented landscape. Consequently, this research aimed to determine whether citizen-collected data can augment traditional science research methods, by comparing and contrasting the abundance of koala sightings gathered by citizen scientists and professional researchers. Based upon the guidelines developed, Koala Quest methodologies were designed, the study conducted, and the efficacy of the project assessed. To combat the high variability of estimated koala populations due to differences in counting techniques, a national monitoring and evaluation program is required, in addition to a standardised method for conducting koala population estimates. Citizen science is a useful method for monitoring animals such as the koala, which are sparsely distributed throughout a vast geographical area, as the large numbers of volunteers recruited by a citizen science project are capable of monitoring a similarly broad spatial range.

  13. Signature of a Pre-Human Population Decline in the Critically Endangered Reunion Island Endemic Forest Bird Coracina newtoni

    PubMed Central

    Salmona, Jordi; Salamolard, Marc; Fouillot, Damien; Ghestemme, Thomas; Larose, Jerry; Centon, Jean-François; Sousa, Vitor; Dawson, Deborah A.; Thebaud, Christophe; Chikhi, Lounès

    2012-01-01

    The exceptional biodiversity of Reunion Island is threatened by anthropogenic landscape changes that took place during the 350 years of human colonization. During this period the human population size increased dramatically from 250 to 800,000. The arrival of humans together with the development of agriculture, invasive species such as rats and cats, and deforestation has lead to the extinction of more than half of the original vertebrate species of the island. For the remaining species, significant work is being carried out to identify threats and conservation status, but little genetic work has been carried on some of the most endangered species. In the last decade theoretical studies have shown the ability of neutral genetic markers to infer the demographic history of endangered species and identify and date past population size changes (expansions or bottlenecks). In this study we provide the first genetic data on the critically endangered species the Reunion cuckoo-shrike Coracina newtoni. The Reunion cuckoo-shrike is a rare endemic forest bird surviving in a restricted 12-km2 area of forested uplands and mountains. The total known population consists of less than one hundred individuals out of which 45 were genotyped using seventeen polymorphic microsatellite loci. We found a limited level of genetic variability and weak population structure, probably due to the limited geographic distribution. Using Bayesian methods, we identified a strong decline in population size during the Holocene, most likely caused by an ancient climatic or volcanic event around 5000 years ago. This result was surprising as it appeared in apparent contradiction with the accepted theory of recent population collapse due to deforestation and predator introduction. These results suggest that new methods allowing for more complex demographic models are necessary to reconstruct the demographic history of populations. PMID:22916272

  14. Signature of a pre-human population decline in the critically endangered Reunion Island endemic forest bird Coracina newtoni.

    PubMed

    Salmona, Jordi; Salamolard, Marc; Fouillot, Damien; Ghestemme, Thomas; Larose, Jerry; Centon, Jean-François; Sousa, Vitor; Dawson, Deborah A; Thebaud, Christophe; Chikhi, Lounès

    2012-01-01

    The exceptional biodiversity of Reunion Island is threatened by anthropogenic landscape changes that took place during the 350 years of human colonization. During this period the human population size increased dramatically from 250 to 800,000. The arrival of humans together with the development of agriculture, invasive species such as rats and cats, and deforestation has lead to the extinction of more than half of the original vertebrate species of the island. For the remaining species, significant work is being carried out to identify threats and conservation status, but little genetic work has been carried on some of the most endangered species. In the last decade theoretical studies have shown the ability of neutral genetic markers to infer the demographic history of endangered species and identify and date past population size changes (expansions or bottlenecks). In this study we provide the first genetic data on the critically endangered species the Reunion cuckoo-shrike Coracina newtoni. The Reunion cuckoo-shrike is a rare endemic forest bird surviving in a restricted 12-km(2) area of forested uplands and mountains. The total known population consists of less than one hundred individuals out of which 45 were genotyped using seventeen polymorphic microsatellite loci. We found a limited level of genetic variability and weak population structure, probably due to the limited geographic distribution. Using Bayesian methods, we identified a strong decline in population size during the Holocene, most likely caused by an ancient climatic or volcanic event around 5000 years ago. This result was surprising as it appeared in apparent contradiction with the accepted theory of recent population collapse due to deforestation and predator introduction. These results suggest that new methods allowing for more complex demographic models are necessary to reconstruct the demographic history of populations.

  15. A retrospective perspective: evaluating population changes by repeating historic bird surveys

    USGS Publications Warehouse

    Igl, Lawrence D.; Johnson, Douglas H.

    2005-01-01

    Acquiring an accurate picture of the changes in bird populations often involves a tradeoff between the time and effort required to complete the surveys and the number of years spent surveying the bird populations. An alternative approach to long-term monitoring efforts is to collect current data and contrast those with data collected earlier in a similar fashion on the same study site(s). To evaluate changes in bird populations, we repeated two extensive surveys, one in North Dakota (1967 vs. 1992-1993) and the other in the Platte River Valley of Nebraska (1979-1980 vs. 2001), where large areas of native vegetation had been converted to agriculture. We use these examples and others from the literature to illustrate the advantages and disadvantages of using historical data as a frame of reference for population changes.

  16. The implications of the historical decline in US energy intensity for long-run CO2 emission projections

    SciTech Connect

    Sue Wing, Ian; Eckaus, Richard S.

    2007-07-17

    This paper analyzes the influence of the long-run decline in US energy intensity on projections of energy use and carbon emissions to the year 2050. We build on our own recent work which decomposes changes in the aggregate US energy–GDP ratio into shifts in sectoral composition (structural change) and adjustments in the energy demand of individual industries (intensity change), and identifies the impact on the latter of price-induced substitution of variable inputs, shifts in the composition of capital and embodied and disembodied technical progress. We employ a recursive-dynamic computable general equilibrium (CGE) model of the US economy to analyze the implications of these findings for future energy use and carbon emissions. Comparison of the simulation results against projections of historical trends in GDP, energy use and emissions reveals that the range of values for the rate of autonomous energy efficiency improvement (AEEI) conventionally used in CGE models is consistent with the effects of structural changes at the sub-sector level, rather than disembodied technological change. Even so, our results suggest that US emissions may well grow faster in the future than in the recent past.

  17. Malignant tumors in two ancient populations: An approach to historical tumor epidemiology.

    PubMed

    Nerlich, Andreas G; Rohrbach, Helmut; Bachmeier, Beatrice; Zink, Albert

    2006-07-01

    The actual increase in the rate of malignant tumors has been ascribed to a higher life expectancy and the influence of various environmental factors. Herein, we present data on the frequency of malignant tumors in paleopathologically well-defined historic populations. Thereby, we looked for malignant growth affecting the skeleton in three study populations of 905 individuals that have been excavated from the necropoles of Thebes-West and Abydos, Upper Egypt covering the time period between 3200 and 500 BC and 2547 individuals that have been buried in a Southern German ossuary dating from between AD 1400 and 1800. The tissue preservation of both the Egyptian and Southern German material was excellent. All available specimens were subjected to a very careful macroscopic examination; isolated findings were also radiologically investigated. In parallel, anthropological data, such as gender and age at death, were recorded. We identified 5 cases of malignant tumors affecting the skeleton in the Egyptian material and 13 cases affecting the skeletal material from Southern Germany. In most instances, multiple osteolytic lesions with slight osteoblastic reaction are strongly suggestive for metastatic carcinoma. Few cases with poorly reactive osteolyses were most compatible with plasmacytoma. Relative tumor frequencies on an age- and sex-adjusted population basis (using a mathematic model of skeletal involvement of malignant tumors in a well-defined English study population from AD 1901 to 1905) indicated that the tumor rates were not statistically different between ancient Egyptian, the historical Southern German and the recent English reference population. These observations indicate that malignant tumors were present in spatially and temporarily different populations over the last 4000 years with an age- and gender-adjusted frequency not different from Western industrial populations of c. 100 years ago. Therefore, we conclude that the current rise in tumor frequencies in

  18. Historical contingency and the evolution of a key innovation in an experimental population of Escherichia coli.

    PubMed

    Blount, Zachary D; Borland, Christina Z; Lenski, Richard E

    2008-06-10

    The role of historical contingency in evolution has been much debated, but rarely tested. Twelve initially identical populations of Escherichia coli were founded in 1988 to investigate this issue. They have since evolved in a glucose-limited medium that also contains citrate, which E. coli cannot use as a carbon source under oxic conditions. No population evolved the capacity to exploit citrate for >30,000 generations, although each population tested billions of mutations. A citrate-using (Cit+) variant finally evolved in one population by 31,500 generations, causing an increase in population size and diversity. The long-delayed and unique evolution of this function might indicate the involvement of some extremely rare mutation. Alternately, it may involve an ordinary mutation, but one whose physical occurrence or phenotypic expression is contingent on prior mutations in that population. We tested these hypotheses in experiments that "replayed" evolution from different points in that population's history. We observed no Cit+ mutants among 8.4 x 10(12) ancestral cells, nor among 9 x 10(12) cells from 60 clones sampled in the first 15,000 generations. However, we observed a significantly greater tendency for later clones to evolve Cit+, indicating that some potentiating mutation arose by 20,000 generations. This potentiating change increased the mutation rate to Cit+ but did not cause generalized hypermutability. Thus, the evolution of this phenotype was contingent on the particular history of that population. More generally, we suggest that historical contingency is especially important when it facilitates the evolution of key innovations that are not easily evolved by gradual, cumulative selection.

  19. Declining incidence of intracerebral hemorrhage over two decades in a population-based study.

    PubMed

    Sacco, S; Ornello, R; Degan, D; Tiseo, C; Pistoia, F; Carolei, A

    2016-11-01

    The incidence and case-fatality rate (CFR) of primary intracerebral hemorrhage (PICH) over two decades were assessed in a prospective population-based study. Cases of incident first-ever PICH were recorded over a 2-year period (2011-2012) from multiple sources in the district of L'Aquila, central Italy. Included patients were followed up to 1 year after the event to ascertain CFRs. Current data were compared with those previously collected from 1994 through 1998. In all, 115 patients (52 men; 45.2%) with a first-ever PICH were included. Mean age ± SD was 77.4 ± 11.8 years. The hemorrhage was lobar in 43 (37.4%) patients, deep in 56 (48.7%), in the posterior fossa in 11 (9.6%) and intraventricular or multiple localized in five (4.3%). Crude annual incidence rate was 19.3 per 100 000 and 14.8 per 100 000 when standardized to the 2011 European population, indicating a 48% reduction comparing data of 2011-2012 to those of 1994-1998 (incidence rate ratio 0.52; 95% confidence interval 0.43-0.64; P < 0.001). In 2011-2012, the 7-day CFR was 27.8%, the 30-day CFR was 42.6% and the 1-year CFR was 52.2%; the 1-year standardized mortality ratio was 0.81 (95% confidence interval 0.63-1.04) compared with 1994-1998. The annual incidence rate of PICH was lower than that found two decades before and close to the rates recently found in other western countries. Data also indicated a non-significant trend towards a decrease in mortality, which nonetheless remained high, pointing to the need for more appropriate treatments in order to reduce PICH severity and mortality. © 2016 EAN.

  20. Future Declines of Coronary Heart Disease Mortality in England and Wales Could Counter the Burden of Population Ageing

    PubMed Central

    Guzman Castillo, Maria; Gillespie, Duncan O. S.; Allen, Kirk; Bandosz, Piotr; Schmid, Volker; Capewell, Simon; O’Flaherty, Martin

    2014-01-01

    Background Coronary Heart Disease (CHD) remains a major cause of mortality in the United Kingdom. Yet predictions of future CHD mortality are potentially problematic due to population ageing and increase in obesity and diabetes. Here we explore future projections of CHD mortality in England & Wales under two contrasting future trend assumptions. Methods In scenario A, we used the conventional counterfactual scenario that the last-observed CHD mortality rates from 2011 would persist unchanged to 2030. The future number of deaths was calculated by applying those rates to the 2012–2030 population estimates. In scenario B, we assumed that the recent falling trend in CHD mortality rates would continue. Using Lee-Carter and Bayesian Age Period Cohort (BAPC) models, we projected the linear trends up to 2030. We validate our methods using past data to predict mortality from 2002–2011. Then, we computed the error between observed and projected values. Results In scenario A, assuming that 2011 mortality rates stayed constant by 2030, the number of CHD deaths would increase 62% or approximately 39,600 additional deaths. In scenario B, assuming recent declines continued, the BAPC model (the model with lowest error) suggests the number of deaths will decrease by 56%, representing approximately 36,200 fewer deaths by 2030. Conclusions The decline in CHD mortality has been reasonably continuous since 1979, and there is little reason to believe it will soon halt. The commonly used assumption that mortality will remain constant from 2011 therefore appears slightly dubious. By contrast, using the BAPC model and assuming continuing mortality falls offers a more plausible prediction of future trends. Thus, despite population ageing, the number of CHD deaths might halve again between 2011 and 2030. This has implications for how the potential benefits of future cardiovascular strategies might best be calculated and presented. PMID:24918442

  1. Sugar Deprivation Reduces Insemination of Anopheles gambiae (Diptera: Culicidae), Despite Daily Recruitment of Adults, and Predicts Decline in Model Populations

    PubMed Central

    STONE, C. M.; TAYLOR, R. M.; ROITBERG, B. D.; FOSTER, W. A.

    2009-01-01

    Our research tests the hypothesis that the inability to sugar-feed reduces the insemination rate in mosquito populations. To test this, we measured the effects of sugar availability on cumulative insemination performance of male Anopheles gambiae Giles s.s. (Diptera: Culicidae) during 10-d periods of continual emergence of equal numbers of both sexes, and we evaluated the implications at the population level with a matrix population model. On each day of each of four replicates, 20 newly emerged mosquitoes of each sex were recruited into the populations within two mesocosms, large walk-in enclosures with simulated natural conditions. Each mesocosm contained a cage to replicate the experiment on a small scale. Scented sucrose was absent or present (control). A human host was available nightly as a bloodmeal source in both mesocosms. Sugar availability and enclosure size significantly influenced female insemination. In the mesocosms, with sugar 49.7% of the females were inseminated, compared with 10.9% of the females without sugar. In the small cages, the insemination rates were 76.0 and 23.5%, respectively. In the mesocosms, cumulative survival of females after 10 d was 51.6% with sugar and 25.6% without sugar. In the cages, female survival was 95 and 73%, respectively. Sensitivity analysis of the population projection matrix shows that both reduced male survival and reduced mating capability due to a lack of sugar contributed to lower insemination rates in females, and in the absence of sugar the insemination rate was lowered to an extent that led to population decline. PMID:19960677

  2. Increasing population and declining biological resources in the context of global change and globalization.

    PubMed

    Ramakrishnan, P S

    2001-11-01

    In the context of over-consumption of natural resources in the name of development and rapid industrialization by a small section of the human population that is rapidly growing, the world is currently faced with a variety of environmental uncertainties. 'Global change' covering a whole variety of ecological issues, and 'globalization' in an economic sense, are two major phenomena that are responsible for these uncertainties. There is increasing evidence to suggest that the developing countries more than the developed, particularly the marginalized traditional (those living close to nature and natural resources) societies would be the worst sufferers. In order to cope with this problem in a situation where the traditional societies have to cope with rapidly depleting biodiversity on which they are dependant for their livelihood, there is an urgent need to explore additional pathways for sustainable management of natural resources and societal development. Such pathways should be based on a landscape management strategy, that takes into consideration the rich traditional ecological knowledge (TEK) that these societies have. This is critical because TEK is the connecting link between conservation and sustainable development. This paper explores the possibilities in this direction through a balanced approach to development, that links the 'traditional' with the 'modern', in a location-specific way.

  3. Overcoming challenges to the recovery of declining amphibian populations in the United States

    USGS Publications Warehouse

    Walls, Susan; Ball, Lianne C.; Barichivich, William J.; Dodd, Kenneth; Enge, Kevin M; Gorman, Thomas A.; O'Donnell, Katherine; Palis, John G; Semlitsch, Raymond D.

    2016-01-01

    The US Endangered Species Act of 1973 (ESA) affords many potential benefits to species threatened with extinction. However, most at-risk amphibians—one of the most imperiled vertebrate groups—remain unlisted under the provisions of the ESA, and many impediments to recovery exist for those species that have been listed. Of the 35 US amphibian species and distinct population segments (“taxa”) listed under the ESA, 40% currently lack a final (completed) recovery plan, 28.6% lack designated critical habitat, and 8.6% lack both. For taxa that have recovery plans, the time between their listing and the development of those plans was from 2 to 29 years, and the time between their listing and the designation of critical habitat ranged from 0 to 14 years. The underlying causes of such delays in protection are complex and constitute obstacles to recovery of imperiled species. We outline a series of strategic actions by which these challenges may be overcome.

  4. New Sources for Comparative Social Science: Historical Population Panel Data From East Asia

    PubMed Central

    Dong, Hao; Campbell, Cameron; Kurosu, Satomi; Yang, Wenshan; Lee, James Z.

    2016-01-01

    Comparison and comparability lie at the heart of any comparative social science. Still, precise comparison is virtually impossible without using similar methods and similar data. In recent decades, social demographers, historians, and economic historians have compiled and made available a large number of micro-level data sets of historical populations for North America and Europe. Studies using these data have already made important contributions to many academic disciplines. In a similar spirit, we introduce five new microlevel historical panel data sets from East Asia, including the China Multi-Generational Panel Dataset–Liaoning (CMGPD-LN) 1749–1909, the China Multi-Generational Panel Dataset– Shuangcheng (CMGPD-SC) 1866–1913, the Japanese Ninbetsu-Aratame-Cho Population Register Database–Shimomoriya and Niita (NAC-SN) 1716–1870, the Korea Multi-Generational Panel Dataset–Tansung (KMGPD-TS) 1678–1888, and the Colonial Taiwan Household Registration Database (CTHRD) 1906–1945. These data sets in total contain more than 3.7 million linked observations of 610,000 individuals and are the first such Asian data to be made available online or by application. We discuss the key features and historical institutions that originally collected these data; the subsequent processes by which the data were reconstructed into individual-level panels; their particular data limitations and strengths; and their potential for comparative social scientific research. PMID:26001625

  5. New Sources for Comparative Social Science: Historical Population Panel Data From East Asia.

    PubMed

    Dong, Hao; Campbell, Cameron; Kurosu, Satomi; Yang, Wenshan; Lee, James Z

    2015-06-01

    Comparison and comparability lie at the heart of any comparative social science. Still, precise comparison is virtually impossible without using similar methods and similar data. In recent decades, social demographers, historians, and economic historians have compiled and made available a large number of micro-level data sets of historical populations for North America and Europe. Studies using these data have already made important contributions to many academic disciplines. In a similar spirit, we introduce five new micro-level historical panel data sets from East Asia, including the China Multi-Generational Panel Dataset-Liaoning (CMGPD-LN) 1749-1909, the China Multi-Generational Panel Dataset-Shuangcheng (CMGPD-SC) 1866-1913, the Japanese Ninbetsu-Aratame-Cho Population Register Database-Shimomoriya and Niita (NAC-SN) 1716-1870, the Korea Multi-Generational Panel Dataset-Tansung (KMGPD-TS) 1678-1888, and the Colonial Taiwan Household Registration Database (CTHRD) 1906-1945. These data sets in total contain more than 3.7 million linked observations of 610,000 individuals and are the first such Asian data to be made available online or by application. We discuss the key features and historical institutions that originally collected these data; the subsequent processes by which the data were reconstructed into individual-level panels; their particular data limitations and strengths; and their potential for comparative social scientific research.

  6. Future Estimation of Convenience Living Facilities Withdrawal due to Population Decline all Over Japan from 2010 TO 2040 - Focus on Supermarkets, Convenience Stores and Drugstores

    NASA Astrophysics Data System (ADS)

    Nishimoto, Yuka; Akiyama, Yuki; Shibasaki, Ryosuke

    2016-06-01

    Population explosion is considered to be one of the most crucial problems in the world. However, in Japan, the opposite problem: population decline has become serious now. Japanese population is estimated to decrease by twenty millions in 2040. This negative situation will cause to increase areas where many residents cannot make a daily living all over Japan because many convenience living facilities such as supermarkets, convenience stores and drugstores will be difficult to maintain their market area population due to future population decline. In our research, we used point data of convenience living facilities developed by address geocoding of digital telephone directory and point data of future population projection developed by distribution of Japanese official population projection data proportionally among the building volume of digital residential map, which can monitor building volumes all over Japan. In conclusion, we estimated that various convenience living facilities in Japan will shrink and close by population decline in near future. In particular, it is cleared that approximately 14.7% of supermarkets will be possible to withdraw all over Japan by 2040. In addition, it is cleared that over 40% of supermarkets in some countryside prefectures will be possible to withdraw by 2040. Thus, we estimated future distributions of convenience living facilities that cannot maintain their market area population due to future population decline. Moreover, we estimated the number of people that they will become inconvenience in buying fresh foods.

  7. Comparative phylogeny and historical perspectives on population genetics of the Pacific hawksbill (Eretmochelys imbricata) and green turtles (Chelonia mydas), inferred from feeding populations in the Yaeyama Islands, Japan.

    PubMed

    Nishizawa, Hideaki; Okuyama, Junichi; Kobayashi, Masato; Abe, Osamu; Arai, Nobuaki

    2010-01-01

    Mitochondrial DNA sequence polymorphisms and patterns of genetic diversity represent the genealogy and relative impacts of historical, geographic, and demographic events on populations. In this study, historical patterns of population dynamics and differentiation in hawksbill (Eretmochelys imbricata) and green turtles (Chelonia mydas) in the Pacific were estimated from feeding populations in the Yaeyama Islands, Japan. Phylogenetic relationships of the haplotypes indicated that hawksbill and green turtles in the Pacific probably underwent very similar patterns and processes of population dynamics over the last million years, with population subdivision during the early Pleistocene and population expansion after the last glacial maximum. These significant contemporary historical events were suggested to have been caused by climatic and sea-level fluctuations. On the other hand, comparing our results to long-term population dynamics in the Atlantic, population subdivisions during the early Pleistocene were specific to Pacific hawksbill and green turtles. Therefore, regional differences in historical population dynamics are suggested. Despite limited sampling locations, these results are the first step in estimating the historical trends in Pacific sea turtles by using phylogenetics and population genetics.

  8. De novo lipogenesis is suppressed during fasting but upregulated at population decline in cyclic voles

    PubMed Central

    Rouvinen-Watt, Kirsti; Harris, Lora; Huitu, Otso; Henttonen, Heikki; Mustonen, Anne-Mari

    2016-01-01

    Arvicolines are susceptible to the development of fatty liver during short-term fasting. We examined the potential role of de novo lipogenesis (DNL) (i) in the development of fasting-induced fatty liver and (ii) during a population cycle by measuring the mRNA expression of acetyl-CoA carboxylase-1 (ACC1) and fatty acid synthase (FAS). Laboratory voles (Microtus oeconomus and Microtus arvalis) were fed or fasted for 12 or 18 h and their liver mRNA levels were determined. Both species showed decreased mRNA expression of ACC1 and FAS during fasting. This suggests that DNL does not participate in the development of fatty liver in voles, different from human non-alcoholic fatty liver disease. In wild bank voles (Myodes glareolus), the mRNA levels of the genes of interest were higher during the population decline compared to the increase phase. In conclusion, DNL was suppressed during acute fasting but upregulated during a long-term population decline—a period of purported scarcity of high-quality food. PMID:26892709

  9. Effects of illegal harvest of eggs on the population decline of leatherback turtles in Las Baulas Marine National Park, Costa Rica.

    PubMed

    Tomillo, Pilar Santidrián; Saba, Vincent S; Piedra, Rotney; Paladino, Frank V; Spotila, James R

    2008-10-01

    Within 19 years the nesting population of leatherback turtles (Dermochelys coriacea) at Parque Nacional Marino Las Baulas declined from 1500 turtles nesting per year to about 100. We analyzed the effects of fishery bycatch and illegal harvesting (poaching) of eggs on this population. We modeled the population response to different levels of egg harvest (90, 75, 50, and 25%) and the effect of eradicating poaching at different times during the population decline. We compared effects of 90% poaching with those of 20% adult mortality because both of these processes were present in the population at Las Baulas. There was a stepwise decline in number of nesting turtles at all levels of egg harvest. Extirpation times for different levels of poaching ranged from 45 to 282 years. The nesting population declined more slowly and survived longer with 20% adult mortality (146 years) than it did with 90% poaching (45 years). Time that elapsed until poaching stopped determined the average population size at which the population stabilized, ranging from 90 to 420 nesting turtles. Our model predicted that saving clutches lost naturally would restore the population when adult mortality rates were low and would contribute more to population recovery when there were short remigration intervals between nesting seasons and a large proportion of natural loss of clutches. Because the model indicated that poaching was the most important cause of the leatherback decline at Las Baulas, protecting nests on the beach and protecting the beach from development are critical for survival of this population. Nevertheless, the model predicted that current high mortality rates of adults will prevent population recovery. Therefore, protection of the beach habitat and nests must be continued and fishery bycatch must be reduced to save this population.

  10. Disruption of Rhino Demography by Poachers May Lead to Population Declines in Kruger National Park, South Africa.

    PubMed

    Ferreira, Sam M; Greaver, Cathy; Knight, Grant A; Knight, Mike H; Smit, Izak P J; Pienaar, Danie

    2015-01-01

    The onslaught on the World's rhinoceroses continues despite numerous initiatives aimed at curbing it. When losses due to poaching exceed birth rates, declining rhino populations result. We used previously published estimates and growth rates for black rhinos (2008) and white rhinos (2010) together with known poaching trends at the time to predict population sizes and poaching rates in Kruger National Park, South Africa for 2013. Kruger is a stronghold for the south-eastern black rhino and southern white rhino. Counting rhinos on 878 blocks 3x3 km in size using helicopters, estimating availability bias and collating observer and detectability biases allowed estimates using the Jolly's estimator. The exponential escalation in number of rhinos poached per day appears to have slowed. The black rhino estimate of 414 individuals (95% confidence interval: 343-487) was lower than the predicted 835 individuals (95% CI: 754-956). The white rhino estimate of 8,968 individuals (95% CI: 8,394-9,564) overlapped with the predicted 9,417 individuals (95% CI: 7,698-11,183). Density- and rainfall-dependent responses in birth- and death rates of white rhinos provide opportunities to offset anticipated poaching effects through removals of rhinos from high density areas to increase birth and survival rates. Biological management of rhinos, however, need complimentary management of the poaching threat as present poaching trends predict detectable declines in white rhino abundances by 2018. Strategic responses such as anti-poaching that protect supply from illegal harvesting, reducing demand, and increasing supply commonly require crime network disruption as a first step complimented by providing options for alternative economies in areas abutting protected areas.

  11. Bird population declines due to radiation exposure at Chernobyl are stronger in species with pheomelanin-based coloration.

    PubMed

    Galván, Ismael; Mousseau, Timothy A; Møller, Anders P

    2011-04-01

    Eumelanin and pheomelanin are the most common pigments providing color to the integument of vertebrates. While pheomelanogenesis requires high levels of a key intracellular antioxidant (glutathione, GSH), eumelanogenesis is inhibited by GSH. This implies that species that possess the molecular basis to produce large amounts of pheomelanin might be more limited in coping with environmental conditions that generate oxidative stress than species that produce eumelanin. Exposure to ionizing radiation produces free radicals and depletes antioxidant resources. GSH is particularly susceptible to radiation, so that species with large proportions of pheomelanic integument may be limited by the availability of GSH to combat oxidative stress and may thus suffer more from radiation effects. We tested this hypothesis in 97 species of birds censused in areas with varying levels of radioactive contamination around Chernobyl. After controlling for the effects of carotenoid-based color, body mass and similarity among taxa due to common phylogenetic descent, the proportion of pheomelanic plumage was strongly negatively related to the slope estimates of the relationship between abundance and radiation levels, while no effect of eumelanic color proportion was found. This represents the first report of an effect of the expression of melanin-based coloration on the capacity to resist the effects of ionizing radiation. Population declines were also stronger in species that exhibit carotenoid-based coloration and have large body mass. The magnitude of population declines had a relatively high phylogenetic signal, indicating that certain groups of birds, especially non-corvid passeriforms, are particularly susceptible to suffer from the effects of radioactive contamination due to phylogenetic inertia.

  12. Are some populations resilient to recessions? Economic fluctuations and mortality during a period of economic decline and recovery in Finland.

    PubMed

    Avendano, Mauricio; Moustgaard, Heta; Martikainen, Pekka

    2017-01-01

    This paper uses individual-level longitudinal data on working-age Finns to examine the health effects of economic fluctuations during a period of economic decline (1989-1996) and recovery (1997-2007) in Finland. We used a nationally representative, longitudinal sample formed by linking population, employment and mortality registers (n = 698,484; 7,719,870 person-years). We implemented a region fixed-effect model that exploits within-regional variations over time in the unemployment rate to identify the effect of economic fluctuations on mortality, controlling for individual employment transitions. Unemployment rates increased from 5.2 % in 1989 to 19.8 % in 1996, declining gradually thereafter and reaching 9.7 % in 2007. Results indicate that these large fluctuations in the economy had no impact on the overall mortality of most working age Finns. The exception was highly educated men, who experienced an increase of 7 % (Rate ratio = 1.07, 95 % confidence interval 1.04, 1.10) for every one-point increase in the regional unemployment rate during the period 1989-1996 due to increased mortality from cardiovascular disease and suicide. This increase, however, was not robust in models that used the employment to population ratio as measure of the economy. Unemployment rates were unrelated to mortality among females, lower educated men, and among any group during economic recovery (1997-2007). For most Finns, we found no consistent evidence of changes in mortality in response to contractions or expansions in the economy. Possible explanations include the weak impact of the recession on wages, as well as the generous unemployment insurance and social benefit system in Finland.

  13. Disruption of Rhino Demography by Poachers May Lead to Population Declines in Kruger National Park, South Africa

    PubMed Central

    Ferreira, Sam M.; Greaver, Cathy; Knight, Grant A.; Knight, Mike H.; Smit, Izak P. J.; Pienaar, Danie

    2015-01-01

    The onslaught on the World’s rhinoceroses continues despite numerous initiatives aimed at curbing it. When losses due to poaching exceed birth rates, declining rhino populations result. We used previously published estimates and growth rates for black rhinos (2008) and white rhinos (2010) together with known poaching trends at the time to predict population sizes and poaching rates in Kruger National Park, South Africa for 2013. Kruger is a stronghold for the south-eastern black rhino and southern white rhino. Counting rhinos on 878 blocks 3x3 km in size using helicopters, estimating availability bias and collating observer and detectability biases allowed estimates using the Jolly’s estimator. The exponential escalation in number of rhinos poached per day appears to have slowed. The black rhino estimate of 414 individuals (95% confidence interval: 343-487) was lower than the predicted 835 individuals (95% CI: 754-956). The white rhino estimate of 8,968 individuals (95% CI: 8,394-9,564) overlapped with the predicted 9,417 individuals (95% CI: 7,698-11,183). Density- and rainfall-dependent responses in birth- and death rates of white rhinos provide opportunities to offset anticipated poaching effects through removals of rhinos from high density areas to increase birth and survival rates. Biological management of rhinos, however, need complimentary management of the poaching threat as present poaching trends predict detectable declines in white rhino abundances by 2018. Strategic responses such as anti-poaching that protect supply from illegal harvesting, reducing demand, and increasing supply commonly require crime network disruption as a first step complimented by providing options for alternative economies in areas abutting protected areas. PMID:26121681

  14. Decline in HIV prevalence among young men in the general population of Cotonou, Benin, 1998-2008.

    PubMed

    Béhanzin, Luc; Diabaté, Souleymane; Minani, Isaac; Lowndes, Catherine M; Boily, Marie-Claude; Labbé, Annie-Claude; Anagonou, Séverin; Zannou, Djimon Marcel; Buvé, Anne; Alary, Michel

    2012-01-01

    To assess changes in the prevalence of HIV and other sexually transmitted infections, as well as in different proximal and distal factors related to HIV infection, in the general population of Cotonou between 1998 and 2008, while an intensive preventive intervention targeting the sex work milieu was ongoing. A two-stage cluster sampling procedure was used to select the participants in each study. Subjects aged 15-49 who agreed to participate were interviewed and tested for HIV, syphilis, HSV-2, gonorrhoea and chlamydia. We used the Roa-Scott Chi-square test (proportions) and the Student's t test (means) for bivariate comparisons, and adjusted logistic regression models taking into account the cluster effect for multivariate analyses. HIV prevalence decreased significantly in men (3.4% in 1998 versus 2.0% in 2008, p = 0.048), especially in those aged 15-29 (3.0% to 0.5%, p = 0.002). Among men, the prevalence of gonorrhoea decreased significantly (1.1% to 0.3%, p = 0.046) while HSV-2 prevalence increased from 12.0% to 18.1% (p = 0.0003). The proportion of men who reported condom use at least once (29.3% to 61.0%, p<0.0001) and of those having attained a secondary educational level or more (17.1% to 61.3%, p<0.0001) also increased significantly. There was an overall decrease in the prevalence of syphilis (1.5% to 0.6%, p = 0.0003). This is the first population-based study reporting a significant decline in HIV prevalence among young men in an African setting where overall prevalence has never reached 5%. The decline occurred while preventive interventions targeting the sex work milieu were ongoing and the educational level was increasing.

  15. Population genetic structure and historical population dynamics of the South American sea lion, Otaria flavescens, in north-central Patagonia.

    PubMed

    Túnez, Juan I; Cappozzo, Humberto L; Nardelli, Maximiliano; Cassini, Marcelo H

    2010-08-01

    The north-central Patagonian coast is the sea lions most abundant area in Argentina. As occurs along the entire Atlantic coast, the distribution of breeding colonies at this smaller geographical scale is also patchy, showing at least three areas with breeding activity. We study the genetic structure and historical population dynamics of the species in five colonies in this area, analysing a 508 base-pair segment of the D-loop control region. Otaria flavescens showed 10 haplotypes with 12 polymorphic sites. The genealogical relationship between haplotypes revealed a shallow pattern of phylogeographic structure. The analysis of molecular variance showed significant differences between colonies, however, pairwise comparisons only indicate significant differences between a pair of colonies belonging to different breeding areas. The pattern of haplotype differentiation and the mismatch distribution analysis suggest a possible bottleneck that would have occurred 64,000 years ago, followed by a demographic expansion of the three southernmost colonies. Thus, the historical population dynamics of O. flavescens in north-central Patagonia appears to be closely related with the dynamics of the Late Pleistocene glaciations.

  16. Long-Term Data Reveal a Population Decline of the Tropical Lizard Anolis apletophallus, and a Negative Affect of El Nino Years on Population Growth Rate

    PubMed Central

    Stapley, Jessica; Garcia, Milton; Andrews, Robin M.

    2015-01-01

    Climate change threatens biodiversity worldwide, however predicting how particular species will respond is difficult because climate varies spatially, complex factors regulate population abundance, and species vary in their susceptibility to climate change. Studies need to incorporate these factors with long-term data in order to link climate change to population abundance. We used 40 years of lizard abundance data and local climate data from Barro Colorado Island to ask how climate, total lizard abundance and cohort-specific abundance have changed over time, and how total and cohort-specific abundance relate to climate variables including those predicted to make the species vulnerable to climate change (i.e. temperatures exceeding preferred body temperature). We documented a decrease in lizard abundance over the last 40 years, and changes in the local climate. Population growth rate was related to the previous years’ southern oscillation index; increasing following cooler-wetter, la niña years, decreasing following warmer-drier, el nino years. Within-year recruitment was negatively related to rainfall and minimum temperature. This study simultaneously identified climatic factors driving long-term population fluctuations and climate variables influencing short-term annual recruitment, both of which may be contributing to the population decline and influence the population’s future persistence. PMID:25671423

  17. Declining HIV Prevalence in Parallel With Safer Sex Behaviors in Burkina Faso: Evidence From Surveillance and Population-Based Surveys

    PubMed Central

    Kirakoya-Samadoulougou, Fati; Nagot, Nicolas; Samadoulougou, Sekou; Sokey, Mamadou; Guiré, Abdoulaye; Sombié, Issiaka; Meda, Nicolas

    2016-01-01

    ABSTRACT Objective: To investigate trends in HIV prevalence and changes in reported sexual behaviors between 1998 and 2014 in Burkina Faso. Methods: We obtained data on HIV prevalence from antenatal care (ANC) surveillance sites (N = 9) that were consistently included in surveillance between 1998 and 2014. We also analyzed data on HIV prevalence and reported sex behaviors from 3 population-based surveys from the Demographic and Health Surveys (DHS), conducted in 1998–99, 2003, and 2010. Sex behavior indicators comprised never-married youth who have never had sex; sex with more than 1 partner; sex with a nonmarital, non-cohabiting partner; condom use at last sex with a nonmarital, non-cohabiting partner; and sex before age 15. We calculated survey-specific HIV prevalence with 95% confidence intervals (CIs) and used the chi-square test or chi-square test for trend to compare HIV prevalence across survey years and to analyze trends in reported sex behaviors. Results: HIV prevalence among pregnant women ages 15–49 decreased by 72% in urban areas, from 7.1% in 1998 to 2.0% in 2014, and by 75% in rural areas, from 2.0% in 2003 to 0.5% in 2014. HIV declined most in younger age groups, which is a good reflection of recent incidence, with declines of 55% among 15–19-year-olds, 72% among 20–24-year-olds, 40% among 25–29-year-olds, and 7% among those ≥30 years old (considering urban and rural data combined). Data reported in the DHS corroborated these declines in HIV prevalence: between 2003 and 2010, HIV prevalence dropped significantly—by 89% among girls ages 15–19, from 0.9% (95% CI, 0.2 to 1.6) to 0.1% (95% CI, 0.0 to 0.4), and by 78% among young women ages 20–24, from 1.8% (95% CI, 1.6 to 3.0) to 0.4% (95% CI, 0.0 to 0.7). During the same time period, people reported safer sex behaviors. For example, significantly higher percentages of never-married youth reported they had never had sex, lower percentages of sexually active youth reported multiple

  18. Reduction in Cadmium Exposure in the United States Population, 1988–2008: The Contribution of Declining Smoking Rates

    PubMed Central

    Navas-Acien, Ana; Caldwell, Kathleen L.; Menke, Andy; Muntner, Paul; Guallar, Eliseo

    2011-01-01

    Background: Public health policies such as tobacco control, air pollution reduction, and hazardous waste remediation may have reduced cadmium exposure among U.S. adults. However, trends in urine cadmium, a marker of cumulative cadmium exposure, have not been evaluated. Objectives: We estimated the trends in urine cadmium concentrations in U.S. adults using data from the National Health and Nutrition Examination Surveys (NHANES) from 1988 to 2008. We also evaluated the impact of changes in the distribution of available cadmium determinants (age, sex, race, education, body mass index, smoking, and occupation) at the population level to explain cadmium trends. Methods: The study population included 19,759 adults ≥ 20 years of age with measures of urine cadmium and cadmium determinants. Results: Age-adjusted geometric means of urine cadmium concentrations were 0.36, 0.35, 0.27, 0.27, 0.28, 0.25, and 0.26 µg/g creatinine in 1988–1991, 1991–1994, 1999–2000, 2001–2002, 2003–2004, 2005–2006, and 2007–2008, respectively. The age, sex, and race/ethnicity-adjusted percent reduction in urine cadmium geometric means comparing 1999–2002 and 2003–2008 with 1988–1994 were 27.8% (95% confidence interval: 22.3%, 32.9%) and 34.3% (29.9%, 38.4%), respectively (p-trend < 0.001), with reductions in all participant subgroups investigated. In never smokers, reductions in serum cotinine accounted for 15.6% of the observed reduction. In ever smokers, changes in smoking cessation, and cumulative and recent dose accounted for 17.1% of the observed reduction. Conclusions: Urine cadmium concentrations decreased markedly between 1988 and 2008. Declining smoking rates and changes in exposure to tobacco smoke may have played an important role in the decline of urine cadmium concentrations, benefiting both smokers and nonsmokers. Cadmium has been associated to several health outcomes in NHANES 1999–2008. Consequently, despite the observed decline, further reduction in

  19. Streamflow Flashiness in the Mid-Atlantic Region: A Historical Analysis of Flashiness and Population Density, Imperviousness and Urban Development

    EPA Science Inventory

    The relationship between stream flashiness and watershed-scale estimates of percent imperviousness, urban development, and population density were used in an historic landscape analysis at the individual watershed spatial scale. GIS technology was employed to spatially associate...

  20. Streamflow Flashiness in the Mid-Atlantic Region: A Historical Analysis of Flashiness and Population Density, Imperviousness and Urban Development

    EPA Science Inventory

    The relationship between stream flashiness and watershed-scale estimates of percent imperviousness, urban development, and population density were used in an historic landscape analysis at the individual watershed spatial scale. GIS technology was employed to spatially associate...

  1. A 5-year Chlamydia vaccination programme could reverse disease-related koala population decline: predictions from a mathematical model using field data.

    PubMed

    Craig, Andrew P; Hanger, Jon; Loader, Jo; Ellis, William A H; Callaghan, John; Dexter, Cathryn; Jones, Darryl; Beagley, Kenneth W; Timms, Peter; Wilson, David P

    2014-07-16

    Many koala populations around Australia are in serious decline, with a substantial component of this decline in some Southeast Queensland populations attributed to the impact of Chlamydia. A Chlamydia vaccine for koalas is in development and has shown promise in early trials. This study contributes to implementation preparedness by simulating vaccination strategies designed to reverse population decline and by identifying which age and sex category it would be most effective to target. We used field data to inform the development and parameterisation of an individual-based stochastic simulation model of a koala population endemic with Chlamydia. The model took into account transmission, morbidity and mortality caused by Chlamydia infections. We calibrated the model to characteristics of typical Southeast Queensland koala populations. As there is uncertainty about the effectiveness of the vaccine in real-world settings, a variety of potential vaccine efficacies, half-lives and dosing schedules were simulated. Assuming other threats remain constant, it is expected that current population declines could be reversed in around 5-6 years if female koalas aged 1-2 years are targeted, average vaccine protective efficacy is 75%, and vaccine coverage is around 10% per year. At lower vaccine efficacies the immunological effects of boosting become important: at 45% vaccine efficacy population decline is predicted to reverse in 6 years under optimistic boosting assumptions but in 9 years under pessimistic boosting assumptions. Terminating a successful vaccination programme at 5 years would lead to a rise in Chlamydia prevalence towards pre-vaccination levels. For a range of vaccine efficacy levels it is projected that population decline due to endemic Chlamydia can be reversed under realistic dosing schedules, potentially in just 5 years. However, a vaccination programme might need to continue indefinitely in order to maintain Chlamydia prevalence at a sufficiently low level

  2. San Francisco 's Golden Gate: A bridge between historically distinct coyote (Canis latrans) populations?

    USGS Publications Warehouse

    Sacks, Benjamin N.; Ernest, Holly B.; Boydston, Erin E.

    2006-01-01

    Although coyotes (Canis latrans) are wellknown for their adaptability to human-modified landscapes (Riley et al. 2003), as with any medium to large-sized carnivore, they typically avoid highly urbanized areas (Crooks 2002), preferring instead to use habitat fragments linked by vegetated corridors (Tigas et al. 2002). However, recent observations of coyotes in San Francisco indicate their willingness to traverse even the most densely urbanized terrain (Rubenstein 2003). Herein we use DNA to show, in an extreme example, that an adult male coyote caught in the northern tip of the San Francisco peninsula traversed the 2-km Golden Gate Bridge, potentially linking historically distinct coyote populations.

  3. Historical and contemporary gene dispersal in wild carrot (Daucus carota ssp. carota) populations

    PubMed Central

    Rong, Jun; Janson, Stef; Umehara, Mikihisa; Ono, Michiyuki; Vrieling, Klaas

    2010-01-01

    Background and Aims Wild carrot is the ancestor of cultivated carrot and is the most important gene pool for carrot breeding. Transgenic carrot may be released into the environment in the future. The aim of the present study was to determine how far a gene can disperse in wild carrot populations, facilitating risk assessment and management of transgene introgression from cultivated to wild carrots and helping to design sampling strategies for germplasm collections. Methods Wild carrots were sampled from Meijendel and Alkmaar in The Netherlands and genotyped with 12 microsatellite markers. Spatial autocorrelation analyses were used to detect spatial genetic structures (SGSs). Historical gene dispersal estimates were based on an isolation by distance model. Mating system and contemporary pollen dispersal were estimated using 437 offspring of 20 mothers with different spatial distances and a correlated paternity analysis in the Meijendel population. Key Results Significant SGSs are found in both populations and they are not significantly different from each other. Combined SGS analysis indicated significant positive genetic correlations up to 27 m. Historical gene dispersal σg and neighbourhood size Nb were estimated to be 4–12 m [95 % confidence interval (CI): 3–25] and 42–73 plants (95 % CI: 28–322) in Meijendel and 10–31 m (95 % CI: 7–∞) and 57–198 plants (95 % CI: 28–∞) in Alkmaar with longer gene dispersal in lower density populations. Contemporary pollen dispersal follows a fat-tailed exponential-power distribution, implying pollen of wild carrots could be dispersed by insects over long distance. The estimated outcrossing rate was 96 %. Conclusions SGSs in wild carrots may be the result of high outcrossing, restricted seed dispersal and long-distance pollen dispersal. High outcrossing and long-distance pollen dispersal suggest high frequency of transgene flow might occur from cultivated to wild carrots and that they could easily spread

  4. Historical and contemporary gene dispersal in wild carrot (Daucus carota ssp. carota) populations.

    PubMed

    Rong, Jun; Janson, Stef; Umehara, Mikihisa; Ono, Michiyuki; Vrieling, Klaas

    2010-08-01

    Wild carrot is the ancestor of cultivated carrot and is the most important gene pool for carrot breeding. Transgenic carrot may be released into the environment in the future. The aim of the present study was to determine how far a gene can disperse in wild carrot populations, facilitating risk assessment and management of transgene introgression from cultivated to wild carrots and helping to design sampling strategies for germplasm collections. Wild carrots were sampled from Meijendel and Alkmaar in The Netherlands and genotyped with 12 microsatellite markers. Spatial autocorrelation analyses were used to detect spatial genetic structures (SGSs). Historical gene dispersal estimates were based on an isolation by distance model. Mating system and contemporary pollen dispersal were estimated using 437 offspring of 20 mothers with different spatial distances and a correlated paternity analysis in the Meijendel population. Significant SGSs are found in both populations and they are not significantly different from each other. Combined SGS analysis indicated significant positive genetic correlations up to 27 m. Historical gene dispersal sigma(g) and neighbourhood size N(b) were estimated to be 4-12 m [95 % confidence interval (CI): 3-25] and 42-73 plants (95 % CI: 28-322) in Meijendel and 10-31 m (95 % CI: 7-infinity) and 57-198 plants (95 % CI: 28-infinity) in Alkmaar with longer gene dispersal in lower density populations. Contemporary pollen dispersal follows a fat-tailed exponential-power distribution, implying pollen of wild carrots could be dispersed by insects over long distance. The estimated outcrossing rate was 96 %. SGSs in wild carrots may be the result of high outcrossing, restricted seed dispersal and long-distance pollen dispersal. High outcrossing and long-distance pollen dispersal suggest high frequency of transgene flow might occur from cultivated to wild carrots and that they could easily spread within and between populations.

  5. Decline and recovery of a large carnivore: environmental change and long-term trends in an endangered brown bear population.

    PubMed

    Martínez Cano, Isabel; Taboada, Fernando González; Naves, Javier; Fernández-Gil, Alberto; Wiegand, Thorsten

    2016-11-30

    Understanding what factors drive fluctuations in the abundance of endangered species is a difficult ecological problem but a major requirement to attain effective management and conservation success. The ecological traits of large mammals make this task even more complicated, calling for integrative approaches. We develop a framework combining individual-based modelling and statistical inference to assess alternative hypotheses on brown bear dynamics in the Cantabrian range (Iberian Peninsula). Models including the effect of environmental factors on mortality rates were able to reproduce three decades of variation in the number of females with cubs of the year (Fcoy), including the decline that put the population close to extinction in the mid-nineties, and the following increase in brown bear numbers. This external effect prevailed over density-dependent mechanisms (sexually selected infanticide and female reproductive suppression), with a major impact of climate driven changes in resource availability and a secondary role of changes in human pressure. Predicted changes in population structure revealed a nonlinear relationship between total abundance and the number of Fcoy, highlighting the risk of simple projections based on indirect abundance indices. This study demonstrates the advantages of integrative, mechanistic approaches and provides a widely applicable framework to improve our understanding of wildlife dynamics.

  6. Climate-associated population declines reverse recovery and threaten future of an iconic high-elevation plant

    USGS Publications Warehouse

    Krushelnycky, Paul D.; Loope, Lloyd L.; Giambelluca, Thomas W.; Starr, Forest; Starr, Kim; Drake, Donald R.; Taylor, Andrew D.; Robichaux, Robert H.

    2013-01-01

    Although climate change is predicted to place mountain-top and other narrowly endemic species at severe risk of extinction, the ecological processes involved in such extinctions are still poorly resolved. In addition, much of this biodiversity loss will likely go unobserved, and therefore largely unappreciated. The Haleakalā silversword is restricted to a single volcano summit in Hawai‘i, but is a highly charismatic giant rosette plant that is viewed by 1–2 million visitors annually. We link detailed local climate data to a lengthy demographic record, and combine both with a population-wide assessment of recent plant mortality and recruitment, to show that after decades of strong recovery following successful management, this iconic species has entered a period of substantial climate-associated decline. Mortality has been highest at the lower end of the distributional range, where most silverswords occur, and the strong association of annual population growth rates with patterns of precipitation suggests an increasing frequency of lethal water stress. Local climate data confirm trends toward warmer and drier conditions on the mountain, and signify a bleak outlook for silverswords if these trends continue. The silversword example foreshadows trouble for diversity in other biological hotspots, and illustrates how even well-protected and relatively abundant species may succumb to climate-induced stresses.

  7. Climate-associated population declines reverse recovery and threaten future of an iconic high-elevation plant.

    PubMed

    Krushelnycky, Paul D; Loope, Lloyd L; Giambelluca, Thomas W; Starr, Forest; Starr, Kim; Drake, Donald R; Taylor, Andrew D; Robichaux, Robert H

    2013-03-01

    Although climate change is predicted to place mountain-top and other narrowly endemic species at severe risk of extinction, the ecological processes involved in such extinctions are still poorly resolved. In addition, much of this biodiversity loss will likely go unobserved, and therefore largely unappreciated. The Haleakalā silversword is restricted to a single volcano summit in Hawai'i, but is a highly charismatic giant rosette plant that is viewed by 1-2 million visitors annually. We link detailed local climate data to a lengthy demographic record, and combine both with a population-wide assessment of recent plant mortality and recruitment, to show that after decades of strong recovery following successful management, this iconic species has entered a period of substantial climate-associated decline. Mortality has been highest at the lower end of the distributional range, where most silverswords occur, and the strong association of annual population growth rates with patterns of precipitation suggests an increasing frequency of lethal water stress. Local climate data confirm trends toward warmer and drier conditions on the mountain, and signify a bleak outlook for silverswords if these trends continue. The silversword example foreshadows trouble for diversity in other biological hotspots, and illustrates how even well-protected and relatively abundant species may succumb to climate-induced stresses.

  8. Canopy Defoliation has More Impact on Carbohydrate Availability than on Hydraulic Function in Declining Scots Pine Populations

    NASA Astrophysics Data System (ADS)

    Poyatos, R.; Aguadé, D.; Gómez, M.; Mencuccini, M.; Martínez-Vilalta, J.

    2013-12-01

    Drought-induced defoliation has recently been associated with depletion of carbohydrate reserves and increased mortality risk in Scots pine (Pinus sylvestris L.) at its dry limit. Are defoliated pines hydraulically impaired compared to non-defoliated pines? Moreover, how do defoliated pines cope with potentially lethal droughts, as compared to non-defoliated pines in the same population? In order to address these questions, we measured the seasonal dynamics of sap flow and needle water potentials (2010-2012), hydraulic function and non-structural carbohydrates (NSC) (2012) in healthy and defoliated pines in the Prades mountains (NE Spain). The summer drought was mild in 2010, intense in 2012 and extremely long in 2011. Defoliated Scots pines showed higher sap flow per unit leaf area during spring, but they were more sensitive to summer drought (Figure 1). This pattern was associated with a steeper decline in soil-to-leaf hydraulic conductance, which could not be explained by differences in branch vulnerability to embolism across defoliation classes. Accordingly, the native loss of xylem conductivity in branches, measured in 2012, remained similar across defoliation classes and reached >65% at the peak of the drought. However, a steeper vulnerability curve was observed for root xylem of defoliated pines. Xylem diameter variations (2011-2012) will be used to further investigate possible differences in the aboveground/belowground partitioning of hydraulic resistance across defoliation classes. NSC levels varied across tree organs (leaves>branches>roots>trunk) and strongly declined with drought. Defoliated pines displayed reduced NSC levels throughout the study period, despite enhanced water transport capacity and increased gas exchange rates during spring. Overall, the defoliated vs. healthy status seems to be more associated to differences in carbohydrate storage and dynamics than to hydraulic differences per se. However, starch conversion to soluble sugars during

  9. State and historically black colleges and universities' collaboration to improve cancer care to underserved populations.

    PubMed

    Harris, Lorna H; Parrish, Theodore; Obano, Nosa; Downing, Beverly; Mcallister, Nancy

    2007-07-01

    One in every two men and one in every three women in North Carolina will be diagnosed with cancer during their lifetime. Cancer is a leading cause of death for ethnic minority populations in North Carolina. The impact on cancer patients, on their families, and on their communities is immeasurable. The burden of cancer in ethnic minority communities can be better addressed if proven advances in prevention, early detection, and care are made available. Historically black colleges and universities (HBCLUs) can play a major role in assisting state governments understand the health needs and health-care delivery preferences of underserved populations. This paper describes these major roles as collaborations between four HBCUs and the state of North Carolina. Recommendations that address improving access to cancer services in the African-American, Hispanic, and American Indian communities are presented.

  10. Historic hybridization and introgression between two iconic Australian anemonefish and contemporary patterns of population connectivity.

    PubMed

    van der Meer, M H; Jones, G P; Hobbs, J-P A; van Herwerden, L

    2012-07-01

    Endemic species on islands are considered at risk of extinction for several reasons, including limited dispersal abilities, small population sizes, and low genetic diversity. We used mitochondrial DNA (D-Loop) and 17 microsatellite loci to explore the evolutionary relationship between an endemic anemonefish, Amphiprion mccullochi (restricted to isolated locations in subtropical eastern Australia) and its more widespread sister species, A. akindynos. A mitochondrial DNA (mtDNA) phylogram showed reciprocal monophyly was lacking for the two species, with two supported groups, each containing representatives of both species, but no shared haplotypes and up to 12 species, but not location-specific management units (MUs). Population genetic analyses suggested evolutionary connectivity among samples of each species (mtDNA), while ecological connectivity was only evident among populations of the endemic, A. mccullochi. This suggests higher dispersal between endemic anemonefish populations at both evolutionary and ecological timeframes, despite separation by hundreds of kilometers. The complex mtDNA structure results from historical hybridization and introgression in the evolutionary past of these species, validated by msat analyses (NEWHYBRIDS, STRUCTURE, and DAPC). Both species had high genetic diversities (mtDNA h > 0.90, π = 4.0%; msat genetic diversity, gd > 0.670). While high gd and connectivity reduce extinction risk, identifying and protecting populations implicated in generating reticulate structure among these species should be a conservation priority.

  11. A global threats overview for Numeniini populations: synthesising expert knowledge for a group of declining migratory birds.

    USGS Publications Warehouse

    Pearce-Higgins, James W.; Brown, Daniel J.; Douglas, David T.; Alves, Jose A.; Bellio, Mariagrazia; Bocher, Pierrick; Buchannan, Graeme M.; Clay, Robert P.; Conklin, Jesse R.; Crockford, Nicola; Dann, Peter; Elts, Jaanus; Friis, Christian; Fuller, Richard A.; Gill, Jennifer A.; Gosbell, Ken; Johnson, James A.; Marquez-Ferrando, Rocio; Masero, Jose´ A.; Melville, David S.; Millington, Spike; Minton, Clive; Mundkur, Taej; Nol, Erika; Pehlak, Hannes; Piersma, Theunis; Rogers, Danny I.; Ruthrauff, Daniel R.; Senner, Nathan R.; Nazeer Shah, Junid; Sheldon, Rob D.; Soloviev, Sergej A.; Tomkovich, Pavel S.; Verkuil, Yvonne I.

    2017-01-01

    current population declines of many Numeniini species and provide a template for the conservation of other groups of threatened species.

  12. Estimating trends of population decline in long-lived marine species in the Mediterranean Sea based on fishers' perceptions.

    PubMed

    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.

  13. Estimating Trends of Population Decline in Long-Lived Marine Species in the Mediterranean Sea Based on Fishers' Perceptions

    PubMed Central

    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 20th 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. PMID:21818268

  14. A Method for Investigating Population Declines of Migratory Birds Using Stable Isotopes: Origins of Harvested Lesser Scaup in North America

    PubMed Central

    Hobson, Keith A.; Wunder, Michael B.; Van Wilgenburg, Steven L.; Clark, Robert G.; Wassenaar, Leonard I.

    2009-01-01

    Background Elucidating geographic locations from where migratory birds are recruited into adult breeding populations is a fundamental but largely elusive goal in conservation biology. This is especially true for species that breed in remote northern areas where field-based demographic assessments are logistically challenging. Methodology/Findings Here we used hydrogen isotopes (δD) to determine natal origins of migrating hatch-year lesser scaup (Aythya affinis) harvested by hunters in the United States from all North American flyways during the hunting seasons of 1999–2000 (n = 412) and 2000–2001 (n = 455). We combined geospatial, observational, and analytical data sources, including known scaup breeding range, δD values of feathers from juveniles at natal sites, models of δD for growing-season precipitation, and scaup band-recovery data to generate probabilistic natal origin landscapes for individual scaup. We then used Monte Carlo integration to model assignment uncertainty from among individual δD variance estimates from birds of known molt origin and also from band-return data summarized at the flyway level. We compared the distribution of scaup natal origin with the distribution of breeding population counts obtained from systematic long-term surveys. Conclusions/Significance Our analysis revealed that the proportion of young scaup produced in the northern (above 60°N) versus the southern boreal and Prairie-Parkland region was inversely related to the proportions of breeding adults using these regions, suggesting that despite having a higher relative abundance of breeding adults, the northern boreal region was less productive for scaup recruitment into the harvest than more southern biomes. Our approach for evaluating population declines of migratory birds (particularly game birds) synthesizes all available distributional data and exploits the advantages of intrinsic isotopic markers that link individuals to geography. PMID:19946360

  15. Investigating the historic long-term population health impact of the US National School Lunch Program.

    PubMed

    Peterson, Cora

    2014-12-01

    The present research aimed to compare historic participation in the US National School Lunch Program (NSLP) during childhood and subsequent prevalence of overweight and obesity among adults at the population level. Regression models examined cross-sectional, state- and age-based panel data constructed from multiple sources, including the Behavioural Risk Factor Surveillance System, US Congressional Record, US Census and the US Department of Agriculture. Models controlled for cohorts' racial/ethnic composition and state poverty rates. Adult-age cohorts (18-34, 35-49, 50-64 and 18-64 years) by US state over a 25-year period (1984-2008). The cohorts' prevalence of overweight and obesity was compared with the cohorts' estimated NSLP participation during schooling (1925-2007; the NSLP began in 1946). Among adults aged 18-64 years, a one percentage-point increase in estimated NSLP participation during schooling between 1925 and 2007 was significantly associated with a 0·29 percentage-point increase in the cohort's later prevalence of overweight and obesity. Analysis of narrower age cohorts and different schooling periods produced mixed results. The NSLP might have influenced population health historically. Longitudinal analysis of individuals from studies now underway will likely facilitate more robust conclusions about the NSLP's long-term health impact based on more recent experiences.

  16. The Dilemma of Decline.

    ERIC Educational Resources Information Center

    Abramowitz, Susan

    This paper, one of two related documents, examines the impact of declining enrollments on educational expenditures. It highlights population and social changes that have contributed to the decline and discusses the general financing of schools. Finally, the paper discusses strategies state policymakers can use to manage decline, including…

  17. Mechanisms of population differentiation in marbled murrelets: historical versus contemporary processes

    USGS Publications Warehouse

    Congdon, B.C.; Piatt, J.F.; Martin, K.; Friesen, V.L.

    2000-01-01

    Mechanisms of population differentiation in highly vagile species such as seabirds are poorly understood. Previous studies of marbled murrelets (Brachyramphus marmoratus; Charadriiformes: Alcidae) found significant population genetic structure, but could not determine whether this structure is due to historical vicariance (e.g., due to Pleistocene glaciers), isolation by distance, drift or selection in peripheral populations, or nesting habitat selection. To discriminate among these possibilities, we analyzed sequence variation in nine nuclear introns from 120 marbled murrelets sampled from British Columbia to the western Aleutian Islands. Mismatch distributions indicated that murrelets underwent at least one population expansion during the Pleistocene and probably are not in genetic equilibrium. Maximum-likelihood analysis of allele frequencies suggested that murrelets from 'mainland' sites (from the Alaskan Peninsula east) are genetically different from those in the Aleutians and that these two lineages diverged prior to the last glaciation. Analyses of molecular variance, as well as estimates of gene flow derived using coalescent theory, indicate that population genetic structure is best explained by peripheral isolation of murrelets in the Aleutian Islands, rather than by selection associated with different nesting habitats. No isolation-by-distance effects could be detected. Our results are consistent with a rapid expansion of murrelets from a single refugium during the early-mid Pleistocene, subsequent isolation and divergence in two or more refugia during the final Pleistocene glacial advance, and secondary contact following retreat of the ice sheets. Population genetic structure now appears to be maintained by distance effects combined with small populations and a highly fragmented habitat in the Aleutian Islands.

  18. Chapter 2: A historical perspective on the population decline of the cactus ferruginous pygmy-owl in Arizona

    Treesearch

    R. Roy Johnson; Jean-Luc E. Cartron; Lois T. Haight; Russell B. Duncan; Kenneth J. Kingsley

    2000-01-01

    The cactus ferruginous pygmy-owl (Glaucidium brasilianum cactorum) was discovered in the U.S. by Bendire in 1872 in the Tucson area (Coues 1872). During the next five decades, naturalists collected many specimens of this owl and typically described the subspecies as common or fairly common along some streams and rivers of central and southern Arizona...

  19. Defining population structure and genetic signatures of decline in the giant garter snake (Thamnophis gigas): implications for conserving threatened species within highly altered landscapes

    USGS Publications Warehouse

    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

  20. Spawning of Bluefin Tuna in the Black Sea: Historical Evidence, Environmental Constraints and Population Plasticity

    PubMed Central

    MacKenzie, Brian R.; Mariani, Patrizio

    2012-01-01

    The lucrative and highly migratory Atlantic bluefin tuna, Thunnus thynnus (Linnaeus 1758; Scombridae), used to be distributed widely throughout the north Atlantic Ocean, Mediterranean Sea and Black Sea. Its migrations have supported sustainable fisheries and impacted local cultures since antiquity, but its biogeographic range has contracted since the 1950s. Most recently, the species disappeared from the Black Sea in the late 1980s and has not yet recovered. Reasons for the Black Sea disappearance, and the species-wide range contraction, are unclear. However bluefin tuna formerly foraged and possibly spawned in the Black Sea. Loss of a locally-reproducing population would represent a decline in population richness, and an increase in species vulnerability to perturbations such as exploitation and environmental change. Here we identify the main genetic and phenotypic adaptations that the population must have (had) in order to reproduce successfully in the specific hydrographic (estuarine) conditions of the Black Sea. By comparing hydrographic conditions in spawning areas of the three species of bluefin tunas, and applying a mechanistic model of egg buoyancy and sinking rate, we show that reproduction in the Black Sea must have required specific adaptations of egg buoyancy, fertilisation and development for reproductive success. Such adaptations by local populations of marine fish species spawning in estuarine areas are common as is evident from a meta-analysis of egg buoyancy data from 16 species of fish. We conclude that these adaptations would have been necessary for successful local reproduction by bluefin tuna in the Black Sea, and that a locally-adapted reproducing population may have disappeared. Recovery of bluefin tuna in the Black Sea, either for spawning or foraging, will occur fastest if any remaining locally adapted individuals are allowed to survive, and by conservation and recovery of depleted Mediterranean populations which could through time re

  1. Historical dimensions of population structure in a continuously distributed marine species: The case of the endemic Chilean dolphin.

    PubMed

    Pérez-Alvarez, M J; Olavarría, C; Moraga, R; Baker, C S; Hamner, R M; Poulin, E

    2016-10-19

    The complementarity of historical and contemporary processes contributes to understanding the genetic structure of continuously distributed marine species with high dispersal capabilities. Cephalorhynchus eutropia, has a continuous coastal distribution with strong genetic differentiation identified by nuclear DNA markers. We explored the historical dimension of this genetic differentiation between northern and southern populations to evaluate phylogeographic structure. Additionally, we conducted mtDNA and microsatellite analyses to detect past and recent demographic changes. The southern population was characterized by lower genetic diversity with a signal of population expansion, likely associated with ice retreat and habitat extension after the Last Glacial Maximum (LGM). In contrast, structure within the northern population was more consistent with stable historical population size. Approximate Bayesian Computation analyses suggested that during the LGM, C. eutropia persisted in the northern area; while the south was colonized by dispersal ~11,000 years ago followed by population expansion. This study shows that Chilean dolphin population structure is consistent with predictions from the Expansion-Contraction biogeographic model, with a poleward post-glacial shift revealed in current genetic structure. The results also confirm the validity of the population units previously identified, demonstrating their historical origin and highlighting the utility of integrating genetic markers with different temporal scale resolutions.

  2. Historical dimensions of population structure in a continuously distributed marine species: The case of the endemic Chilean dolphin

    PubMed Central

    Pérez-Alvarez, M. J.; Olavarría, C.; Moraga, R.; Baker, C. S.; Hamner, R. M.; Poulin, E.

    2016-01-01

    The complementarity of historical and contemporary processes contributes to understanding the genetic structure of continuously distributed marine species with high dispersal capabilities. Cephalorhynchus eutropia, has a continuous coastal distribution with strong genetic differentiation identified by nuclear DNA markers. We explored the historical dimension of this genetic differentiation between northern and southern populations to evaluate phylogeographic structure. Additionally, we conducted mtDNA and microsatellite analyses to detect past and recent demographic changes. The southern population was characterized by lower genetic diversity with a signal of population expansion, likely associated with ice retreat and habitat extension after the Last Glacial Maximum (LGM). In contrast, structure within the northern population was more consistent with stable historical population size. Approximate Bayesian Computation analyses suggested that during the LGM, C. eutropia persisted in the northern area; while the south was colonized by dispersal ~11,000 years ago followed by population expansion. This study shows that Chilean dolphin population structure is consistent with predictions from the Expansion-Contraction biogeographic model, with a poleward post-glacial shift revealed in current genetic structure. The results also confirm the validity of the population units previously identified, demonstrating their historical origin and highlighting the utility of integrating genetic markers with different temporal scale resolutions. PMID:27759113

  3. Mini-Nutritional Assessment predicts functional decline of elderly Taiwanese: result of a population-representative sample.

    PubMed

    Lee, Li-Chin; Tsai, Alan C

    2012-06-01

    Nutrition is a key element in geriatric health and is important for functional ability. The present study examined the functional status-predictive ability of the Mini-Nutritional Assessment (MNA). We analysed the dataset of the 'Survey of Health and Living Status of the Elderly in Taiwan', a population-based study conducted by the Bureau of Health Promotion of Taiwan. Study subjects (≥65 years old) who completed both the 1999 and 2003 surveys were rated with the long form and short form of the MNA at baseline and with the Activities of Daily Living (ADL) and the Instrument Activities of Daily Living (IADL) scales 4 years later (end-point). The ability of the MNA to predict ADL or IADL dependency was evaluated with logistic regression models. The results showed that the elderly who were rated malnourished or at risk of malnutrition at baseline generally had significantly higher ADL or IADL scores 4 years later. Lower baseline MNA scores also predicted a greater risk of ADL or IADL dependency. These associations exist even among the elderly who were free of ADL or IADL dependency at baseline. The results clearly indicate that the MNA is able to predict ADL and IADL dependency (in addition to rating current nutritional status) of the elderly. The MNA, especially the short form, should be a valuable tool for identifying elderly at risk of functional decline and/or malnutrition in clinical practice or community programmes.

  4. Population Structure and Historical Demography of the Oriental River Prawn (Macrobrachium nipponense) in Taiwan.

    PubMed

    Chen, Po-Cheng; Shih, Chun-Han; Chu, Ta-Jen; Wang, Daryi; Lee, Ying-Chou; Tzeng, Tzong-Der

    2015-01-01

    The oriental river prawn (Macrobrachium nipponense) is a non-obligatory amphidromous prawn, and it has a wide distribution covering almost the entire Taiwan. Mitochondrial DNA fragment sequences of the cytochrome oxidase subunit I (COI) and 16S rRNA were combined and used to elucidate the population structure and historical demography of oriental river prawn in Taiwan. A total of 202 individuals from six reservoirs and three estuaries were separately collected. Nucleotide diversity (π) of all populations was 0.01217, with values ranging from 0.00188 (Shihmen Reservoir, SMR, northern Taiwan) to 0.01425 (Mingte Reservoir, MTR, west-central Taiwan). All 76 haplotypes were divided into 2 lineages: lineage A included individuals from all sampling areas except SMR, and lineage B included specimens from all sampling locations except Chengching Lake Reservoir (CLR) and Liyu Lake Reservoir (LLR). All FST values among nine populations were significantly different except the one between Jhonggang River Estuary (JGE, west-central Taiwan) and Kaoping River Estuary (KPE, southern Taiwan). UPGMA tree of nine populations showed two main groups: the first group included the SMR and Tamsui River Estuary (TSE) (both located northern Taiwan), and the second one included the other seven populations (west-central, southern and eastern Taiwan). Demographic analyses implied a population expansion occurred during the recent history of the species. The dispersal route of this species might be from China to west-central and west-southern Taiwan, and then the part individuals belonging to lineage A and B dispersed southerly and northerly, respectively. And then part individuals in west-central Taiwan fell back to and stay at estuaries as the sea level rose about 18,000 years ago.

  5. Population Structure and Historical Demography of the Oriental River Prawn (Macrobrachium nipponense) in Taiwan

    PubMed Central

    Chu, Ta-Jen; Wang, Daryi; Lee, Ying-Chou; Tzeng, Tzong-Der

    2015-01-01

    The oriental river prawn (Macrobrachium nipponense) is a non-obligatory amphidromous prawn, and it has a wide distribution covering almost the entire Taiwan. Mitochondrial DNA fragment sequences of the cytochrome oxidase subunit I (COI) and 16S rRNA were combined and used to elucidate the population structure and historical demography of oriental river prawn in Taiwan. A total of 202 individuals from six reservoirs and three estuaries were separately collected. Nucleotide diversity (π) of all populations was 0.01217, with values ranging from 0.00188 (Shihmen Reservoir, SMR, northern Taiwan) to 0.01425 (Mingte Reservoir, MTR, west-central Taiwan). All 76 haplotypes were divided into 2 lineages: lineage A included individuals from all sampling areas except SMR, and lineage B included specimens from all sampling locations except Chengching Lake Reservoir (CLR) and Liyu Lake Reservoir (LLR). All FST values among nine populations were significantly different except the one between Jhonggang River Estuary (JGE, west-central Taiwan) and Kaoping River Estuary (KPE, southern Taiwan). UPGMA tree of nine populations showed two main groups: the first group included the SMR and Tamsui River Estuary (TSE) (both located northern Taiwan), and the second one included the other seven populations (west-central, southern and eastern Taiwan). Demographic analyses implied a population expansion occurred during the recent history of the species. The dispersal route of this species might be from China to west-central and west-southern Taiwan, and then the part individuals belonging to lineage A and B dispersed southerly and northerly, respectively. And then part individuals in west-central Taiwan fell back to and stay at estuaries as the sea level rose about 18,000 years ago. PMID:26716687

  6. [Birth planning being a historical trend of population evolution in China].

    PubMed

    Yang, Z T

    1980-07-01

    China has historically valued and promoted population growth. Throughout the centuries, China's population development was characterized by 4 trends: 1) High birth rate caused by: a patriarchical system and ethical philosophy of ancestor worship which required a continuous family line, plus a system of private ownership where land was the primary means of production; a political philosophy that encouraged births and punished the lack of offspring; and a social attitude that promoted early marriages. 2) High death rate caused by: civil wars and violent struggles for power; natural disasters; plague; and infanticide of female babies. 3) A relatively slow rate of population growth resulting from high birth and death rates. 4) A relatively sparse population and abundant land prior to the Qing Dynasty (1644-1911). With the establishment of a new China, basic changes occurred in the social system and the means of production. For 30 years (1949-1979), China enjoyed peace, higher educational and public health standards, and was free from disastrous natural calamities, a consequence of which was a higher birth rate and lower death rate. Concurrently the thinking was that "the more people the better," so that population grew at an alarming rate. From 1949 to 1979, China's population increased by 422,150,000, compared with its previous 2000 years in which the population had increased nearly 400,000,000. In 1965, the national birth rate was 38.06/1000 compared with 19.95/1000 in 1944 for the 6 largest cities. The death rate in 1938 was 28.2/1000, but by 1965 it had dropped to 9.55/1000. The rate of natural population growth in 1965 was 28.51/1000 compared with the highest rate in China's history of 1957/1000 durint the Eastern Huan Dynasty (25-189 A.D.). Unfortunately there has been no conscious policy to plan population growth along with economic growth, so that population grew uncontrolled and people had less land per person than at any other time in China's history. Thus

  7. Detecting warning signs of trouble within population fluctuations: using capture-recapture modeling to uncover changes in population dynamics leading to declines

    USGS Publications Warehouse

    Spendelow, J.A.; Nichols, J.D.; Kendall, W.L.; Hines, J.E.; Hatfield, J.S.; Nisbet, I.C.T.

    2004-01-01

    An intensive mark-recapture/resighting program has been carried out on the Roseate Terns nesting at Falkner Island, Connecticut, since the late 1980s as part of a regional study of the metapopulation dynamics and ecology of the endangered Northwest Atlantic breeding population of this species. Substantial losses of tern eggs and chicks to predation at this colony site began in 1996 when at least five Black-crowned Night-Herons started nocturnal raids. This depredation has been a major factor in the reduction of productivity from an average of about 1.0 chicks/pair for the 10 years before night-heron predation began to as low as about 0.2 chicks/pair in 2002. Recent capture-recapture modelling analyses have detected other important impacts on the population dynamics of the Roseate Terns at this site including a reduction by about half in the 'development-of-residency' rates of first-time breeders, and a substantial decline in the local 'survival-and-fidelity' rates of experienced breeders believed due mostly to increased immigration rates to other colony sites.

  8. Foraging Habitat Quality Constrains Effectiveness of Artificial Nest-Site Provisioning in Reversing Population Declines in a Colonial Cavity Nester

    PubMed Central

    Catry, Inês; Franco, Aldina M. A.; Rocha, Pedro; Alcazar, Rita; Reis, Susana; Cordeiro, Ana; Ventim, Rita; Teodósio, Joaquim; Moreira, Francisco

    2013-01-01

    Among birds, breeding numbers are mainly limited by two resources of major importance: food supply and nest-site availability. Here, we investigated how differences in land-use and nest-site availability affected the foraging behaviour, breeding success and population trends of the colonial cavity-dependent lesser kestrel Falco naumanni inhabiting two protected areas. Both areas were provided with artificial nests to increase nest-site availability. The first area is a pseudo-steppe characterized by traditional extensive cereal cultivation, whereas the second area is a previous agricultural zone now abandoned or replaced by forested areas. In both areas, lesser kestrels selected extensive agricultural habitats, such as fallows and cereal fields, and avoided scrubland and forests. In the second area, tracked birds from one colony travelled significantly farther distances (6.2 km ±1.7 vs. 1.8 km ±0.4 and 1.9 km ±0.6) and had significant larger foraging-ranges (144 km2 vs. 18.8 and 14.8 km2) when compared to the birds of two colonies in the extensive agricultural area. Longer foraging trips were reflected in lower chick feeding rates, lower fledging success and reduced chick fitness. Availability and occupation of artificial nests was high in both areas but population followed opposite trends, with a positive increment recorded exclusively in the first area with a large proportion of agricultural areas. Progressive habitat loss around the studied colony in the second area (suitable habitat decreased from 32% in 1990 to only 7% in 2002) is likely the main driver of the recorded population decline and suggests that the effectiveness of bird species conservation based on nest-site provisioning is highly constrained by habitat quality in the surrounding areas. Therefore, the conservation of cavity-dependent species may be enhanced firstly by finding the best areas of remaining habitat and secondly by increasing the carrying capacity of high-quality habitat areas

  9. Foraging habitat quality constrains effectiveness of artificial nest-site provisioning in reversing population declines in a colonial cavity nester.

    PubMed

    Catry, Inês; Franco, Aldina M A; Rocha, Pedro; Alcazar, Rita; Reis, Susana; Cordeiro, Ana; Ventim, Rita; Teodósio, Joaquim; Moreira, Francisco

    2013-01-01

    Among birds, breeding numbers are mainly limited by two resources of major importance: food supply and nest-site availability. Here, we investigated how differences in land-use and nest-site availability affected the foraging behaviour, breeding success and population trends of the colonial cavity-dependent lesser kestrel Falco naumanni inhabiting two protected areas. Both areas were provided with artificial nests to increase nest-site availability. The first area is a pseudo-steppe characterized by traditional extensive cereal cultivation, whereas the second area is a previous agricultural zone now abandoned or replaced by forested areas. In both areas, lesser kestrels selected extensive agricultural habitats, such as fallows and cereal fields, and avoided scrubland and forests. In the second area, tracked birds from one colony travelled significantly farther distances (6.2 km ± 1.7 vs. 1.8 km ± 0.4 and 1.9 km ± 0.6) and had significant larger foraging-ranges (144 km(2) vs. 18.8 and 14.8 km(2)) when compared to the birds of two colonies in the extensive agricultural area. Longer foraging trips were reflected in lower chick feeding rates, lower fledging success and reduced chick fitness. Availability and occupation of artificial nests was high in both areas but population followed opposite trends, with a positive increment recorded exclusively in the first area with a large proportion of agricultural areas. Progressive habitat loss around the studied colony in the second area (suitable habitat decreased from 32% in 1990 to only 7% in 2002) is likely the main driver of the recorded population decline and suggests that the effectiveness of bird species conservation based on nest-site provisioning is highly constrained by habitat quality in the surrounding areas. Therefore, the conservation of cavity-dependent species may be enhanced firstly by finding the best areas of remaining habitat and secondly by increasing the carrying capacity of high-quality habitat areas

  10. Historical Pedigree Reconstruction from Extant Populations Using PArtitioning of RElatives (PREPARE)

    PubMed Central

    Shem-Tov, Doron; Halperin, Eran

    2014-01-01

    Recent technological improvements in the field of genetic data extraction give rise to the possibility of reconstructing the historical pedigrees of entire populations from the genotypes of individuals living today. Current methods are still not practical for real data scenarios as they have limited accuracy and assume unrealistic assumptions of monogamy and synchronized generations. In order to address these issues, we develop a new method for pedigree reconstruction, , which is based on formulations of the pedigree reconstruction problem as variants of graph coloring. The new formulation allows us to consider features that were overlooked by previous methods, resulting in a reconstruction of up to 5 generations back in time, with an order of magnitude improvement of false-negatives rates over the state of the art, while keeping a lower level of false positive rates. We demonstrate the accuracy of compared to previous approaches using simulation studies over a range of population sizes, including inbred and outbred populations, monogamous and polygamous mating patterns, as well as synchronous and asynchronous mating. PMID:24945698

  11. Atrophy of the residual alveolar ridge following tooth loss in an historical population.

    PubMed

    Reich, K M; Huber, C D; Lippnig, W R; Ulm, C; Watzek, G; Tangl, S

    2011-01-01

    To study the natural aetiopathology of jaw atrophy after tooth loss, unaltered by prosthetic procedures, an historical population without modern dental treatment was examined. Based on the hypothesis that there are predictable changes in shape during jaw-atrophy, frequency and degree of atrophy as well as clinical aspects of bone quality and resorption were determined in the skeletal remains of 263 individuals. The potential association between age and frequency/severity of atrophy was analysed. Atrophy in at least one jaw segment was present in 45.2% of the analysed jaw specimens. The residual ridge underwent a series of changes in shape and height following the pattern of resorption described for modern populations. The severity of these alterations was associated with the age of the individual and the region within the jaw. Atrophy was frequently related to structural degradation of the covering cortical layer. These findings prove that atrophy of the jaw evidently does occur, displaying similar patterns of resorption in a population without modern prosthetics, where the negative effect of ill-fitting dentures is excluded. The basic information about alterations of shape and the cortical layer covering the residual crest might help to provide a deeper insight into aetiopathological mechanisms of this common oral disease. © 2010 John Wiley & Sons A/S.

  12. Historical pedigree reconstruction from extant populations using PArtitioning of RElatives (PREPARE).

    PubMed

    Shem-Tov, Doron; Halperin, Eran

    2014-06-01

    Recent technological improvements in the field of genetic data extraction give rise to the possibility of reconstructing the historical pedigrees of entire populations from the genotypes of individuals living today. Current methods are still not practical for real data scenarios as they have limited accuracy and assume unrealistic assumptions of monogamy and synchronized generations. In order to address these issues, we develop a new method for pedigree reconstruction, [Formula: see text], which is based on formulations of the pedigree reconstruction problem as variants of graph coloring. The new formulation allows us to consider features that were overlooked by previous methods, resulting in a reconstruction of up to 5 generations back in time, with an order of magnitude improvement of false-negatives rates over the state of the art, while keeping a lower level of false positive rates. We demonstrate the accuracy of [Formula: see text] compared to previous approaches using simulation studies over a range of population sizes, including inbred and outbred populations, monogamous and polygamous mating patterns, as well as synchronous and asynchronous mating.

  13. Historical and contemporary mating patterns in remnant populations of the forest tree Fraxinus excelsior L.

    PubMed

    Bacles, Cecile F E; Burczyk, Jaroslaw; Lowe, Andrew J; Ennos, Richard A

    2005-05-01

    Genetic variation at microsatellite markers was used to quantify genetic structure and mating behavior in a severely fragmented population of the wind-pollinated, wind-dispersed temperate tree Fraxinus excelsior in a deforested catchment in Scotland. Remnants maintain high levels of genetic diversity, comparable with those reported for continuous populations in southeastern Europe, and show low interpopulation differentiation (E = 0.080), indicating that historical gene exchange has not been limited (Nm = 3.48). We estimated from seeds collected from all trees producing fruits in three of five remnants that F. excelsior is predominantly outcrossing (t(m) = 0.971 +/- 0.028). Use of a neighborhood model approach to describe the relative contribution of local and long-distance pollen dispersal indicates that pollen gene flow into each of the three remnants is extensive (46-95%) and pollen dispersal has two components. The first is very localized and restricted to tens of meters around the mother trees. The second is a long-distance component with dispersal occurring over several kilometers. Effective dispersal distances, accounting for the distance and directionality to mother trees of sampled pollen donors, average 328 m and are greater than values reported for a continuous population. These results suggest that the opening of the landscape facilitates airborne pollen movement and may alleviate the expected detrimental genetic effects of fragmentation.

  14. Ethnically distinct populations of historical Tibet exhibit distinct autosomal STR compositions.

    PubMed

    Tsering, Thupten; Gayden, Tenzin; Chennakrishnaiah, Shilpa; Bukhari, Areej; Garcia-Bertrand, Ralph; Herrera, Rene J

    2016-03-01

    At an average altitude of 4000m above sea level, the Tibetan plateau is one of the highest plains on the planet. It is surrounded on three sides by massive mountain ranges: the Kunlun, the Karakoram and the Himalayas. These natural barriers have kept Tibet relatively isolated. In the present study, 15 autosomal STR loci were genotyped in 338 unrelated individuals from three traditional provinces of historical Tibet: Amdo (86), Kham (101) and U-Tsang (151). All the studied loci were in Hardy-Weinberg equilibrium except for the D19S433 locus in the Kham province. FGA, D21S11 and D2S1338 show the highest observed heterozygosity values in Amdo (0.8954), Kham (0.9208) and U-Tsang (0.8940), respectively, whereas TPOX is the least variable marker displaying the lowest value for the same parameter. U-Tsang exhibits the highest total numbers of alleles (139) followed by Kham (130) and Amdo (128) groups. The allele frequency data from this study were compared to relevant global reference populations. Our results indicate that although these three Tibetan populations group together in both the Correspondence Analysis (CA) plot and the Neighbor Joining (NJ) tree, they exhibit some degree of genetic differentiation among themselves congruent with their unique dialects, cultures and traditions. The 15 autosomal STR loci studied were found to be informative and discriminating, thereby providing a useful set of markers for population genetic studies. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Investigations of fine-scale phylogeography in Tigriopus californicus reveal historical patterns of population divergence.