WorldWideScience

Sample records for bird population declines

  1. Emerging infectious disease leads to rapid population declines of common British birds.

    Directory of Open Access Journals (Sweden)

    Robert A Robinson

    Full Text Available 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.

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

    Science.gov (United States)

    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

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

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    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.

  4. EU protected area network did not prevent a country wide population decline in a threatened grassland bird.

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    Silva, João P; Correia, Ricardo; Alonso, Hany; Martins, Ricardo C; D'Amico, Marcello; Delgado, Ana; Sampaio, Hugo; Godinho, Carlos; Moreira, Francisco

    2018-01-01

    Few studies have assessed the effectiveness of the Protected Area networks on the conservation status of target species. Here, we assess the effectiveness of the Portuguese Natura 2000 (the European Union network of protected areas) in maintaining a species included in the Annex I of the Bird Directive, namely the population of a priority farmland bird, the little bustard Tetrax tetrax . We measured the effectiveness of the Natura 2000 by comparing population trends across time (2003-2006 and 2016) in 51 areas, 21 of which within 12 Special Protection Areas (SPA) that were mostly designated for farmland bird conservation and another 30 areas without EU protection. Overall, the national population is estimated to have declined 49% over the last 10-14 years. This loss was found to be proportionally larger outside SPA (64% decline) compared to losses within SPA (25% decline). However, the absolute male density decline was significantly larger within SPA . In spite of holding higher population densities and having prevented habitat loss, we conclude that Natura 2000 was not effective in buffering against the overall bustard population decline. Results show that the mere designation of SPA in farmland is not enough to secure species populations and has to be combined with agricultural policies and investment to maintain not only habitat availability but also habitat quality.

  5. EU protected area network did not prevent a country wide population decline in a threatened grassland bird

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    João P. Silva

    2018-01-01

    Full Text Available Background Few studies have assessed the effectiveness of the Protected Area networks on the conservation status of target species. Here, we assess the effectiveness of the Portuguese Natura 2000 (the European Union network of protected areas in maintaining a species included in the Annex I of the Bird Directive, namely the population of a priority farmland bird, the little bustard Tetrax tetrax. Methods We measured the effectiveness of the Natura 2000 by comparing population trends across time (2003–2006 and 2016 in 51 areas, 21 of which within 12 Special Protection Areas (SPA that were mostly designated for farmland bird conservation and another 30 areas without EU protection. Results Overall, the national population is estimated to have declined 49% over the last 10–14 years. This loss was found to be proportionally larger outside SPA (64% decline compared to losses within SPA (25% decline. However, the absolute male density decline was significantly larger within SPA . Discussion In spite of holding higher population densities and having prevented habitat loss, we conclude that Natura 2000 was not effective in buffering against the overall bustard population decline. Results show that the mere designation of SPA in farmland is not enough to secure species populations and has to be combined with agricultural policies and investment to maintain not only habitat availability but also habitat quality.

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

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    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

  7. A method for investigating population declines of migratory birds using stable isotopes: origins of harvested lesser scaup in North America.

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    Keith A Hobson

    2009-11-01

    Full Text Available 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.Here we used hydrogen isotopes (deltaD 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, deltaD values of feathers from juveniles at natal sites, models of deltaD 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 deltaD 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.Our analysis revealed that the proportion of young scaup produced in the northern (above 60 degrees 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.

  8. A Method for Investigating Population Declines of Migratory Birds Using Stable Isotopes: Origins of Harvested Lesser Scaup in North America

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    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

  9. Are snake populations in widespread decline?

    OpenAIRE

    Reading, C. J.; Luiselli, L. M.; Akani, G. C.; Bonnet, X.; Amori, G.; Ballouard, J. M.; Filippi, E.; Naulleau, G.; Pearson, D.; Rugiero, L.

    2010-01-01

    Long-term studies have revealed population declines in fishes, amphibians, reptiles, birds and mammals. In birds, and particularly amphibians, these declines are a global phenomenon whose causes are often unclear. Among reptiles, snakes are top predators and therefore a decline in their numbers may have serious consequences for the functioning of many ecosystems. Our results show that, of 17 snake populations (eight species) from the UK, France, Italy, Nigeria and Australia, 11 have declined ...

  10. A global threats overview for Numeniini populations: synthesising expert knowledge for a group of declining migratory birds.

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    Pearce-Higgins, James W.; Brown, Daniel J.; Douglas, David T.; Alves, José 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, José 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.

  11. Long-term decline of a winter-resident bird community in Puerto Rico

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    J. Faaborg; W. J. Arendt; J. D. Toms; K. M. Dugger; W. A. Cox; M. Canals Mora

    2013-01-01

    Despite concern expressed two decades ago, there has been little recent discussion about continuing declines of migrant bird populations. Monitoring efforts have been focused almost exclusively on the breeding grounds. We describe the long-term decline of a winter-resident bird population in Guanica Commonwealth Forest, Puerto Rico, one of the last remaining tracts of...

  12. Are snake populations in widespread decline?

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    Reading, C J; Luiselli, L M; Akani, G C; Bonnet, X; Amori, G; Ballouard, J M; Filippi, E; Naulleau, G; Pearson, D; Rugiero, L

    2010-12-23

    Long-term studies have revealed population declines in fishes, amphibians, reptiles, birds and mammals. In birds, and particularly amphibians, these declines are a global phenomenon whose causes are often unclear. Among reptiles, snakes are top predators and therefore a decline in their numbers may have serious consequences for the functioning of many ecosystems. Our results show that, of 17 snake populations (eight species) from the UK, France, Italy, Nigeria and Australia, 11 have declined sharply over the same relatively short period of time with five remaining stable and one showing signs of a marginal increase. Although the causes of these declines are currently unknown, we suspect that they are multi-faceted (such as habitat quality deterioration, prey availability), and with a common cause, e.g. global climate change, at their root.

  13. Anthropogenically-Mediated Density Dependence in a Declining Farmland Bird.

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    Jenny C Dunn

    Full Text Available Land management intrinsically influences the distribution of animals and can consequently alter the potential for density-dependent processes to act within populations. For declining species, high densities of breeding territories are typically considered to represent productive populations. However, as density-dependent effects of food limitation or predator pressure may occur (especially when species are dependent upon separate nesting and foraging habitats, high territory density may limit per-capita productivity. Here, we use a declining but widespread European farmland bird, the yellowhammer Emberiza citrinella L., as a model system to test whether higher territory densities result in lower fledging success, parental provisioning rates or nestling growth rates compared to lower densities. Organic landscapes held higher territory densities, but nests on organic farms fledged fewer nestlings, translating to a 5 times higher rate of population shrinkage on organic farms compared to conventional. In addition, when parental provisioning behaviour was not restricted by predation risk (i.e., at times of low corvid activity, nestling provisioning rates were higher at lower territory densities, resulting in a much greater increase in nestling mass in low density areas, suggesting that food limitation occurred at high densities. These findings in turn suggest an ecological trap, whereby preferred nesting habitat does not provide sufficient food for rearing nestlings at high population density, creating a population sink. Habitat management for farmland birds should focus not simply on creating a high nesting density, but also on ensuring heterogeneous habitats to provide food resources in close proximity to nesting birds, even if this occurs through potentially restricting overall nest density but increasing population-level breeding success.

  14. Advanced long-term bird banding and climate data mining in spring confirm passerine population declines for the Northeast Chinese-Russian flyway

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    Jiao, Shengwu; Huettmann, Falk; Guo, Yumin; Li, Xianda; Ouyang, Yanlan

    2016-09-01

    The migration of birds is fascinating for humans but it's also a serious environmental monitoring and management issue on a global level. Bird banding using mistnets has been the method of choice for decades worldwide; linking these data with climate data allows to infer on global warming and outlier events. However, good methods to achieve this effectively in time and space for many species are still missing; data for Asia are specifically sparse and often 'messy'. Here we present a data mining summary information for data from two bird banding stations (Gaofeng and Qingfeng) along the vast Northeast Chinese-Russian flyway. Bird data were collected during spring 2002-2011 with standardized techniques and then linked with related climate data in the banding as well as the wintering sites. This creates a complex data set which is based on a decade and which includes many predictors. This first-time data mining analysis with 'data cloning' and machine learning methods (boosted regression trees) shows how to extract the major signals in this unique dataset from highly correlated and interacting predictors. Our results indicate a large-scale warming trend for the flyway, with a start in 2003, and a freezing rain outlier event in 2008; the last years remained on a rather warm level. All evidence along this vast flyway supports major changes, warming trends, habitat losses and consequently strong passerine declines. Presumably human pressures are a major factor either way and we propose to address these problems immediately for betterment if meaningful conservation targets are to be met.

  15. Do people fear population decline?

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    van Dalen, H.P.; Henkens, C.J.I.M.

    2011-01-01

    This week the world population is projected to reach seven billion. Yet in some countries the prospect of a decline in population is worrying policymakers far more. This columns asks what the people think, focusing on a survey from the Netherlands. It turns out that most people are in favour of

  16. Singapore’s Declining Population

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    2010-01-01

    ethnic groups work . In addition, they get married later in life and had fewer children. What does a declining population mean for Singapore...other countries. BACKGROUND Since gaining independence, Singapore’s population has grown along with its economy . As Singapore’s gross domestic...in the country mean fewer consumers. Fewer people in the country also means there are less people to support the elderly. As the population ages

  17. Exotic birds increase generalization and compensate for native bird decline in plant-frugivore assemblages.

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    García, Daniel; Martínez, Daniel; Stouffer, Daniel B; Tylianakis, Jason M

    2014-11-01

    Exotic species are thought to alter the structure of natural communities and disrupt ecosystem functioning through invasion. Nevertheless, exotic species may also provide ecological insurance when they contribute to maintain ecosystem functions after the decline of native species following anthropogenic disturbance. Here, this hypothesis is tested with the assemblage of frugivorous birds and fleshy-fruited plants of New Zealand, which has suffered strong historical declines in native birds while simultaneously gaining new frugivores introduced by European settlers. We studied the plant-frugivore assemblage from measures of fruit and bird abundances and fruit consumption in nine forest patches, and tested how this changed across a gradient of relative abundance of exotic birds. We then examined how each bird species' role in the assemblage (the proportion of fruits and the number of plant species consumed) varied with their relative abundance, body size and native/exotic status. The more abundant and, to a lesser extent, larger birds species consumed a higher proportion of fruits from more plant species. Exotic birds consumed fruits less selectively and more proportionate to the local availability than did native species. Interaction networks in which exotic birds had a stronger role as frugivores had higher generalization, higher nestedness and higher redundancy of plants. Exotic birds maintained frugivory when native birds became rarer, and diversified the local spectrum of frugivores for co-occurring native plants. These effects seemed related to the fact that species abundances, rather than trait-matching constraints, ultimately determined the patterns of interactions between birds and plants. By altering the structure of plant-frugivore assemblages, exotic birds likely enhance the stability of the community-wide seed dispersal in the face of continued anthropogenic impact. © 2014 The Authors. Journal of Animal Ecology © 2014 British Ecological Society.

  18. Effects of oil pollution on marine bird populations

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    Piatt, John F.; Carter, Harry R.; Nettleship, David N.; White, Jan

    1991-01-01

    Worldwide oil pollution has killed millions of marine birds in this century but it has been difficult to directly link these losses to population declines. Estimated bird losses from acute spills and chronic pollution are not precise because we usually do not know the proportion of birds killed at sea that are detected on beach surveys or the origin of those birds. Data required to assess effects on populations (abundance, distribution, productivity, recruitment and mortality rates) are inadequate or absent for many species. Local populations may sometimes be devastated by oil pollution, but whether these losses are biologically significant to global populations, especially in light of natural or human-induced sources of mortality, is debatable. In this paper. We review the evidence for effects of oil on marine bird populations, discuss four case histories, and address the debate concerning short- and long-term effects on avian populations.

  19. Who fears and who welcomes population decline?

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    Hendrik P. Van Dalen

    2011-08-01

    Full Text Available European countries are experiencing population decline and the tacit assumption in most analyses is that the decline may have detrimental welfare effects. In this paper we use a survey among the population in the Netherlands to discover whether population decline is always met with fear. A number of results stand out: population size preferences differ by geographic proximity: at a global level the majority of respondents favors a (global population decline, but closer to home one supports a stationary population. Population decline is clearly not always met with fear: 31 percent would like the population to decline at the national level and they generally perceive decline to be accompanied by immaterial welfare gains (improvement environment as well as material welfare losses (tax increases, economic stagnation. In addition to these driving forces it appears that the attitude towards immigrants is a very strong determinant at all geographical levels: immigrants seem to be a stronger fear factor than population decline.

  20. NIDI scenario. Strong population decline in China

    OpenAIRE

    de Beer, J.A.A.

    2016-01-01

    United Nations projections assume that by the end of this century one third of the world population will live in India, China or Nigeria. While population growth in India will slow down and the population size of China will decline, population growth in Nigeria will accelerate. A new NIDI scenario projects less population growth in Nigeria and sharp population decline in China.

  1. Climate change and the decline of a once common bird

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    McClure, Christopher J W; Rolek, Brian W; McDonald, Kenneth; Hill, Geoffrey E

    2012-01-01

    Climate change is predicted to negatively impact wildlife through a variety of mechanisms including retraction of range. We used data from the North American Breeding Bird Survey and regional and global climate indices to examine the effects of climate change on the breeding distribution of the Rusty Blackbird (Euphagus carolinus), a formerly common species that is rapidly declining. We found that the range of the Rusty Blackbird retracted northward by 143 km since the 1960s and that the probability of local extinction was highest at the southern range margin. Furthermore, we found that the mean breeding latitude of the Rusty Blackbird was significant and positively correlated with the Pacific Decadal Oscillation with a lag of six years. Because the annual distribution of the Rusty Blackbird is affected by annual weather patterns produced by the Pacific Decadal Oscillation, our results support the hypothesis that directional climate change over the past 40 years is contributing to the decline of the Rusty Blackbird. Our study is the first to implicate climate change, acting through range retraction, in a major decline of a formerly common bird species. PMID:22423330

  2. Causes and consequences of spatial variation in sex ratios in a declining bird species.

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    Morrison, Catriona A; Robinson, Robert A; Clark, Jacquie A; Gill, Jennifer A

    2016-09-01

    Male-biased sex ratios occur in many bird species, particularly in those with small or declining populations, but the causes of these skews and their consequences for local population demography are rarely known. Within-species variation in sex ratios can help to identify the demographic and behavioural processes associated with such biases. Small populations may be more likely to have skewed sex ratios if sex differences in survival, recruitment or dispersal vary with local abundance. Analyses of species with highly variable local abundances can help to identify these mechanisms and the implications for spatial variation in demography. Many migratory bird species are currently undergoing rapid and severe declines in abundance in parts of their breeding ranges and thus have sufficient spatial variation in abundance to explore the extent of sex ratio biases, their causes and implications. Using national-scale bird ringing data for one such species (willow warbler, Phylloscopus trochilus), we show that sex ratios vary greatly across Britain and that male-biased sites are more frequent in areas of low abundance, which are now widespread across much of south and east England. These sex ratio biases are sufficient to impact local productivity, as the relative number of juveniles caught at survey sites declines significantly with increasing sex ratio skew. Sex differences in survival could influence this sex ratio variation, but we find little evidence for sex differences in survival increasing with sex ratio skew. In addition, sex ratios have become male-biased over the last two decades, but there are no such trends in adult survival rates for males or females. This suggests that lower female recruitment into low abundance sites is contributing to these skews. These findings suggest that male-biased sex ratios in small and declining populations can arise through local-scale sex differences in survival and dispersal, with females recruiting disproportionately into larger

  3. Enigmatic declines in bird numbers in lowland forest of eastern Ecuador may be a consequence of climate change

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    John G. Blake

    2015-08-01

    Full Text Available Bird populations have declined in many parts of the world but most of those declines can be attributed to effects of human activities (e.g., habitat fragmentation; declines in areas unaffected by human activities are not common. We have been sampling bird populations at an undisturbed site in lowland forest of eastern Ecuador annually since 2001 using a combination of mist nets and direct observations on two 100-ha plots. Bird numbers fluctuated on both plots during the first 8 years but did not show a consistent pattern of change. Since about 2008, numbers of birds on both plots have declined; capture rates in 2014 were ∼40% less than at the start of the study and observation rates were ∼50% less. Both understory and canopy species declined in abundance. Overall, insectivores showed the most pronounced declines but declines varied among trophic groups. The period from 2008 onward also was a period of stronger La Niña events which, at this study site, are associated with increased rainfall. The mechanism for the declines is not known but likely reflects a combination of reduced reproductive success coupled with reduced survival associated with changing climate.

  4. Breeding bird populations in Missouri Ozark forests with and without clearcutting

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    Frank R., III Thompson; William D. Dijak; Thomas G. Kulowiec; David A. Hamilton

    1992-01-01

    Concern has arisen that forest management practices that create edge (such as clearcutting) are contributing to regional declines in neotropical migrant birds that inhabit forest interiors. Consequently, we studied breeding bird populations in an extensively forested region of southern Missouri to determine if the numbers of breeding birds differed between areas (n = 9...

  5. Habitat availability is a more plausible explanation than insecticide acute toxicity for U.S. grassland bird species declines

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    Hill, Jason M.; Egan, J. Franklin; Stauffer, Glenn E.; Diefenbach, Duane R.

    2014-01-01

    Grassland bird species have experienced substantial declines in North America. These declines have been largely attributed to habitat loss and degradation, especially from agricultural practices and intensification (the habitat-availability hypothesis). A recent analysis of North American Breeding Bird Survey (BBS) “grassland breeding” bird trends reported the surprising conclusion that insecticide acute toxicity was a better correlate of grassland bird declines in North America from 1980–2003 (the insecticide-acute-toxicity hypothesis) than was habitat loss through agricultural intensification. In this paper we reached the opposite conclusion. We used an alternative statistical approach with additional habitat covariates to analyze the same grassland bird trends over the same time frame. Grassland bird trends were positively associated with increases in area of Conservation Reserve Program (CRP) lands and cropland used as pasture, whereas the effect of insecticide acute toxicity on bird trends was uncertain. Our models suggested that acute insecticide risk potentially has a detrimental effect on grassland bird trends, but models representing the habitat-availability hypothesis were 1.3–21.0 times better supported than models representing the insecticide-acute-toxicity hypothesis. Based on point estimates of effect sizes, CRP area and agricultural intensification had approximately 3.6 and 1.6 times more effect on grassland bird trends than lethal insecticide risk, respectively. Our findings suggest that preserving remaining grasslands is crucial to conserving grassland bird populations. The amount of grassland that has been lost in North America since 1980 is well documented, continuing, and staggering whereas insecticide use greatly declined prior to the 1990s. Grassland birds will likely benefit from the de-intensification of agricultural practices and the interspersion of pastures, Conservation Reserve Program lands, rangelands and other grassland

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

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    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...

  7. The role of thermal physiology in recent declines of birds in a biodiversity hotspot

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    Milne, Robyn; Cunningham, Susan J; Lee, Alan T K

    2015-01-01

    Abstract We investigated whether observed avian range contractions and population declines in the Fynbos biome of South Africa were mechanistically linked to recent climate warming. We aimed to determine whether there were correlations between preferred temperature envelope, or changes in temperature within species' ranges, and recent changes in range and population size, for 12 Fynbos-resident bird species, including six that are endemic to the biome. We then measured the physiological responses of each species at air temperatures ranging from 24 to 42°C to determine whether physiological thermal thresholds could provide a mechanistic explanation for observed population trends. Our data show that Fynbos-endemic species occupying the coolest regions experienced the greatest recent reductions in range and population size (>30% range reduction between 1991 and the present). In addition, species experiencing the largest increases in air temperature within their ranges showed the greatest declines. However, evidence for a physiological mechanistic link between warming and population declines was equivocal, with only the larger species showing low thermal thresholds for their body mass, compared with other birds globally. In addition, some species appear more vulnerable than others to air temperatures in their ranges above physiological thermal thresholds. Of these, the high-altitude specialist Cape rockjumper (Chaetops frenatus) seems most at risk from climate warming. This species showed: (i) the lowest threshold for increasing evaporative water loss at high temperatures; and (ii) population declines specifically in those regions of its range recording significant warming trends. Our findings suggest that caution must be taken when attributing causality explicitly to thermal stress, even when population trends are clearly correlated with rates of warming. Studies explicitly investigating the mechanisms underlying such correlations will be key to appropriate

  8. NIDI scenario. Strong population decline in China

    NARCIS (Netherlands)

    de Beer, J.A.A.

    2016-01-01

    United Nations projections assume that by the end of this century one third of the world population will live in India, China or Nigeria. While population growth in India will slow down and the population size of China will decline, population growth in Nigeria will accelerate. A new NIDI scenario

  9. Feral Pigs, Introduced Mosquitoes, and the Decline of Hawai'i's Native Birds

    Science.gov (United States)

    LaPointe, Dennis A.

    2006-01-01

    The introduction of mosquitoes, avian pox, and avian malaria to the Hawaiian Islands has had a profound effect on the geographical distribution and population number of highly susceptible Hawaiian honeycreepers, and likely contributed to the extinction of several species. While the mosquito vector (disease-carrier) is most closely associated with human activity, in remote Hawaiian rain forests, feral pigs may be pivotally important to the disease system. Since 1991, USGS scientists have taken a leadership position in identifying the role these diseases continue to play in the decline and extinction of native Hawaiian forest birds and in finding ways to mitigate their impacts.

  10. Desertification: measuring population decline in rural Ireland.

    Science.gov (United States)

    Cawley, M E

    1994-10-01

    "This paper addresses the issue of rural population decline in the Republic of Ireland during the past two decades having regard to size of place and estimated net migration for key age groups. The analysis is pursued at the level of some 160 Rural Districts. The results of the analysis confirm expected relationships between peripheral locations, small population size and a depletion of the young working age groups. The method used, however, permits the links between size of place, population change and the composition of that change to be identified with some precision." excerpt

  11. Spatial and temporal variation in population trends in a long-distance migratory bird

    OpenAIRE

    Morrison, CA; Robinson, RA; Clark, JA; Gill, JA

    2010-01-01

    Over the past three decades, evidence has been growing that many Afro-Palaearctic migratory bird populations have suffered sustained and severe declines. As causes of these declines exist across both the breeding and non-breeding season, identifying potential drivers of population change is complex. In order to explore the roles of changes in regional and local environmental conditions on population change, we examine spatial and temporal variation in population trajectories of one of Europe’...

  12. Terrestrial bird population trends on Aguiguan (Goat Island), Mariana Islands

    Science.gov (United States)

    Amidon, Fred; Camp, Richard J.; Marshall, Ann P.; Pratt, Thane K.; Williams, Laura; Radley, Paul; Cruz, Justine B.

    2014-01-01

    The island of Aguiguan is part of the Mariana archipelago and currently supports populations of four endemic species, including one endemic genus, Cleptornis. Bird population trends since 1982 were recently assessed on the neighbouring islands of Saipan, Tinian, and Rota indicating declines in some native species. Point-transect surveys were conducted in 2008 by the U.S. Fish and Wildlife Service to assess population densities and trends on Aguiguan. Densities for six of the nine native birds—White-throated Ground-dove Gallicolumba xanthonura, Collared Kingfisher Todiramphus chloris, Rufous Fantail Rhipidura rufifrons, Golden White-eye Cleptornis marchei, Bridled White-eye Zosterops conspicillatus and Micronesian Starling Aplonis opaca—and the non-native bird—Island Collared-dove Streptopelia bitorquata—were significantly greater in 2008 than in 1982. No differences in densities were detected among the surveys for Mariana Fruit-dove Ptilinopus roseicapilla, and Micronesian MyzomelaMyzomela rubratra. Three federally and locally listed endangered birds—Nightingale Reed-warbler Acrocephalus luscinius, Mariana Swiftlet Collocalia bartschi, and Micronesian Megapode Megapodius laperous)—were either not detected during the point-transect counts, the surveys were not appropriate for the species, or the numbers of birds detected were too small to estimate densities. The factors behind the increasing trends for some species are unknown but may be related to increased forest cover on the island since 1982. With declining trends for some native species on neighbouring islands, the increasing and stable trends on Aguiguan is good news for forest bird populations in the region, as Aguiguan populations can help support conservation efforts on other islands in the archipelago.

  13. Population Genetic Aspects of Pollinator Decline

    Directory of Open Access Journals (Sweden)

    Laurence Packer

    2001-06-01

    Full Text Available We reviewed the theory of conservation genetics, with special emphasis on the influence of haplodiploidy and other aspects of bee biology upon conservation genetic parameters. We then investigated the possibility that pollinator decline can be addressed in this way, using two meta-analytical approaches on genetic data from the Hymenoptera and the Lepidoptera. First, we compared levels of heterozygosity between the orders. As has been found previously, the haplodiploid Hymenoptera had markedly lower levels of genetic variation than the Lepidoptera. Bees had even lower levels, and bumble bees, in particular, often seemed almost monomorphic genetically. However, the statistically confounding effects of phylogeny render detailed interpretation of such data difficult. Second, we investigated patterns of gene flow among populations of these insects. Hymenoptera were far more likely to show genetic effects of population fragmentation than are Lepidoptera, even at similar geographic distances between populations. The reduced effective population sizes resulting from haplodiploidy probably contributed to this result. The proportion of species with low levels of gene flow did not vary among the different taxonomic groups within the Hymenoptera.

  14. Beached bird surveys indicate decline in chronic oil pollution in the North Sea

    International Nuclear Information System (INIS)

    Camphuysen, K.C.J.

    1998-01-01

    Strandings of oiled seabirds have been a signal of the ongoing problem of chronic oil pollution in the North Sea since the beginning of the twentieth century. Overall numbers of beached birds are subject to enormous fluctuations, being the result, for example, of changes in the amount of oil spilled in the marine environment, currents, the frequency of onshore winds and variations in the numbers of seabirds in a given region. In contrast, oil rates, being the fraction of oiled birds of the total stranded, appeared to be relatively constant while specific for different species and regions. A power analysis of the results of beached bird surveys demonstrated the sensitivity of these data as a tool to monitor trends in oil rates of stranded birds. Rather subtle changes in oil rates could be demonstrated, indicating positive results of attempts to protect certain sea areas (e.g. the Wadden Sea) and a decline in oil rates over time. (author)

  15. The future demographic niche of a declining grassland bird fails to shift poleward in response to climate change

    Science.gov (United States)

    McCauley, Lisa A.; Ribic, Christine; Pomara, Lars Y.; Zuckerberg, Benjamin

    2017-01-01

    ContextTemperate grasslands and their dependent species are exposed to high variability in weather and climate due to the lack of natural buffers such as forests. Grassland birds are particularly vulnerable to this variability, yet have failed to shift poleward in response to recent climate change like other bird species in North America. However, there have been few studies examining the effect of weather on grassland bird demography and consequent influence of climate change on population persistence and distributional shifts.ObjectivesThe goal of this study was to estimate the vulnerability of Henslow’s Sparrow (Ammodramus henslowii), an obligate grassland bird that has been declining throughout much of its range, to past and future climatic variability.MethodsWe conducted a demographic meta-analysis from published studies and quantified the relationship between nest success rates and variability in breeding season climate. We projected the climate-demography relationships spatially, throughout the breeding range, and temporally, from 1981 to 2050. These projections were used to evaluate population dynamics by implementing a spatially explicit population model.ResultsWe uncovered a climate-demography linkage for Henslow’s Sparrow with summer precipitation, and to a lesser degree, temperature positively affecting nest success. We found that future climatic conditions—primarily changes in precipitation—will likely contribute to reduced population persistence and a southwestward range contraction.ConclusionsFuture distributional shifts in response to climate change may not always be poleward and assessing projected changes in precipitation is critical for grassland bird conservation and climate change adaptation.

  16. Avian blood parasite infection during the non-breeding season: an overlooked issue in declining populations?

    Science.gov (United States)

    2013-01-01

    Background Pathogens and parasites can have major impacts on host population dynamics, both through direct mortality and via indirect effects. Both types of effect may be stronger in species whose populations are already under pressure. We investigated the potential for blood parasites to impact upon their hosts at the immunological, physiological and population level during the non-breeding season using a declining population of yellowhammers Emberiza citrinella as a model. Results Yellowhammers infected by Haemoproteus spp. showed both a reduced heterophil to lymphocyte (H:L) ratio, and an elevated standardised white blood cell (WBC) count compared to uninfected birds, indicating an immunological response to infection. Infected birds had shorter wings during the first winter of sampling but not during the second, colder, winter; survival analysis of 321 birds sampled across four winters indicated that increased wing length conferred a survival advantage. Conclusions We suggest that the potential impacts of blood parasite infections on over-wintering birds may have been underestimated. Further research should consider the potential impacts of sub-clinical parasite infections on the dynamics of vulnerable populations, and we suggest using declining populations as model systems within which to investigate these relationships as well as examining interactions between sub-clinical disease and other environmental stressors. JEL Code Q5 PMID:24011390

  17. Population Development of Baltic Bird Species: Great Cormorant (Phalacrocorax carbo sinensis) - Update with results from 2011

    DEFF Research Database (Denmark)

    Herrmann, Christof; Bregnballe, Thomas; Larsson, Kjell

    2011-01-01

    During the 19th century, the Great Cormorant was exterminated as a breeding bird in several Baltic countries. The persecution continued until the mid of the 20th century, and in the early 1960s the European breeding population of the continental subspecies sinensis had declined to 4 000 breeding...

  18. Bird population density estimated from acoustic signals

    Science.gov (United States)

    Dawson, D.K.; Efford, M.G.

    2009-01-01

    Many animal species are detected primarily by sound. Although songs, calls and other sounds are often used for population assessment, as in bird point counts and hydrophone surveys of cetaceans, there are few rigorous methods for estimating population density from acoustic data. 2. The problem has several parts - distinguishing individuals, adjusting for individuals that are missed, and adjusting for the area sampled. Spatially explicit capture-recapture (SECR) is a statistical methodology that addresses jointly the second and third parts of the problem. We have extended SECR to use uncalibrated information from acoustic signals on the distance to each source. 3. We applied this extension of SECR to data from an acoustic survey of ovenbird Seiurus aurocapilla density in an eastern US deciduous forest with multiple four-microphone arrays. We modelled average power from spectrograms of ovenbird songs measured within a window of 0??7 s duration and frequencies between 4200 and 5200 Hz. 4. The resulting estimates of the density of singing males (0??19 ha -1 SE 0??03 ha-1) were consistent with estimates of the adult male population density from mist-netting (0??36 ha-1 SE 0??12 ha-1). The fitted model predicts sound attenuation of 0??11 dB m-1 (SE 0??01 dB m-1) in excess of losses from spherical spreading. 5.Synthesis and applications. Our method for estimating animal population density from acoustic signals fills a gap in the census methods available for visually cryptic but vocal taxa, including many species of bird and cetacean. The necessary equipment is simple and readily available; as few as two microphones may provide adequate estimates, given spatial replication. The method requires that individuals detected at the same place are acoustically distinguishable and all individuals vocalize during the recording interval, or that the per capita rate of vocalization is known. We believe these requirements can be met, with suitable field methods, for a significant

  19. Breeding bird populations and habitat associations within the Savannah River Site (SRS).

    Energy Technology Data Exchange (ETDEWEB)

    Gauthreaux, Sidney, A.; Steven J. Wagner.

    2005-06-29

    Gauthreaux, Sidney, A., and Steven J. Wagner. 2005. Breeding bird populations and habitat associations within the Savannah River Site (SRS). Final Report. USDA Forest Service, Savannah River, Aiken, SC. 48 pp. Abstract: During the 1970's and 1980's a dramatic decline occurred in the populations of Neotropical migratory birds, species that breed in North America and winter south of the border in Central and South America and in the Caribbean. In 1991 an international initiative was mounted by U. S. governmental land management agencies, nongovernmental conservation agencies, and the academic and lay ornithological communities to understand the decline of Neotropical migratory birds in the Americas. In cooperation with the USDA Forest Service - Savannah River (FS - SR) we began 1992 a project directed to monitoring population densities of breeding birds using the Breeding Bird Census (BBC) methodology in selected habitats within the Savannah River Site SRS. In addition we related point count data on the occurrence of breeding Neotropical migrants and other bird species to the habitat data gathered by the Forest Inventory and Analysis (FIA) program of the USDA Forest Service and data on habitat treatments within forest stands.

  20. Consequences of habitat change and resource selection specialization for population limitation in cavity-nesting birds

    Science.gov (United States)

    Martin, Thomas E.

    2015-01-01

    Resource selection specialization may increase vulnerability of populations to environmental change. One environmental change that may negatively impact some populations is the broad decline of quaking aspen Populus tremuloides, a preferred nest tree of cavity-nesting organisms who are commonly limited by nest-site availability. However, the long-term consequences of this habitat change for cavity-nesting bird populations are poorly studied.

  1. American exceptionalism: population trends and flight initiation distances in birds from three continents.

    Directory of Open Access Journals (Sweden)

    Anders Pape Møller

    Full Text Available All organisms may be affected by humans' increasing impact on Earth, but there are many potential drivers of population trends and the relative importance of each remains largely unknown. The causes of spatial patterns in population trends and their relationship with animal responses to human proximity are even less known.We investigated the relationship between population trends of 193 species of bird in North America, Australia and Europe and flight initiation distance (FID; the distance at which birds take flight when approached by a human. While there is an expected negative relationship between population trend and FID in Australia and Europe, we found the inverse relationship for North American birds; thus FID cannot be used as a universal predictor of vulnerability of birds. However, the analysis of the joint explanatory ability of multiple drivers (farmland breeding habitat, pole-most breeding latitude, migratory habit, FID effects on population status replicated previously reported strong effects of farmland breeding habitat (an effect apparently driven mostly by European birds, as well as strong effects of FID, body size, migratory habit and continent. Farmland birds are generally declining.Flight initiation distance is related to population trends in a way that differs among continents opening new research possibilities concerning the causes of geographic differences in patterns of anti-predator behavior.

  2. American exceptionalism: population trends and flight initiation distances in birds from three continents.

    Science.gov (United States)

    Møller, Anders Pape; Samia, Diogo S M; Weston, Mike A; Guay, Patrick-Jean; Blumstein, Daniel T

    2014-01-01

    All organisms may be affected by humans' increasing impact on Earth, but there are many potential drivers of population trends and the relative importance of each remains largely unknown. The causes of spatial patterns in population trends and their relationship with animal responses to human proximity are even less known. We investigated the relationship between population trends of 193 species of bird in North America, Australia and Europe and flight initiation distance (FID); the distance at which birds take flight when approached by a human. While there is an expected negative relationship between population trend and FID in Australia and Europe, we found the inverse relationship for North American birds; thus FID cannot be used as a universal predictor of vulnerability of birds. However, the analysis of the joint explanatory ability of multiple drivers (farmland breeding habitat, pole-most breeding latitude, migratory habit, FID) effects on population status replicated previously reported strong effects of farmland breeding habitat (an effect apparently driven mostly by European birds), as well as strong effects of FID, body size, migratory habit and continent. Farmland birds are generally declining. Flight initiation distance is related to population trends in a way that differs among continents opening new research possibilities concerning the causes of geographic differences in patterns of anti-predator behavior.

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

    Directory of Open Access Journals (Sweden)

    Lynna Kvistad

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

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

    Science.gov (United States)

    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.

  5. Quantifying the Detrimental Impacts of Land-Use and Management Change on European Forest Bird Populations

    Science.gov (United States)

    Wade, Amy S. I.; Barov, Boris; Burfield, Ian J.; Gregory, Richard D.; Norris, Ken; Butler, Simon J.

    2013-01-01

    The ecological impacts of changing forest management practices in Europe are poorly understood despite European forests being highly managed. Furthermore, the effects of potential drivers of forest biodiversity decline are rarely considered in concert, thus limiting effective conservation or sustainable forest management. We present a trait-based framework that we use to assess the detrimental impact of multiple land-use and management changes in forests on bird populations across Europe. Major changes to forest habitats occurring in recent decades, and their impact on resource availability for birds were identified. Risk associated with these changes for 52 species of forest birds, defined as the proportion of each species' key resources detrimentally affected through changes in abundance and/or availability, was quantified and compared to their pan-European population growth rates between 1980 and 2009. Relationships between risk and population growth were found to be significantly negative, indicating that resource loss in European forests is an important driver of decline for both resident and migrant birds. Our results demonstrate that coarse quantification of resource use and ecological change can be valuable in understanding causes of biodiversity decline, and thus in informing conservation strategy and policy. Such an approach has good potential to be extended for predictive use in assessing the impact of possible future changes to forest management and to develop more precise indicators of forest health. PMID:23704997

  6. Quantifying the detrimental impacts of land-use and management change on European forest bird populations.

    Directory of Open Access Journals (Sweden)

    Amy S I Wade

    Full Text Available The ecological impacts of changing forest management practices in Europe are poorly understood despite European forests being highly managed. Furthermore, the effects of potential drivers of forest biodiversity decline are rarely considered in concert, thus limiting effective conservation or sustainable forest management. We present a trait-based framework that we use to assess the detrimental impact of multiple land-use and management changes in forests on bird populations across Europe. Major changes to forest habitats occurring in recent decades, and their impact on resource availability for birds were identified. Risk associated with these changes for 52 species of forest birds, defined as the proportion of each species' key resources detrimentally affected through changes in abundance and/or availability, was quantified and compared to their pan-European population growth rates between 1980 and 2009. Relationships between risk and population growth were found to be significantly negative, indicating that resource loss in European forests is an important driver of decline for both resident and migrant birds. Our results demonstrate that coarse quantification of resource use and ecological change can be valuable in understanding causes of biodiversity decline, and thus in informing conservation strategy and policy. Such an approach has good potential to be extended for predictive use in assessing the impact of possible future changes to forest management and to develop more precise indicators of forest health.

  7. Pesticide acute toxicity is a better correlate of U.S. grassland bird declines than agricultural intensification.

    Directory of Open Access Journals (Sweden)

    Pierre Mineau

    Full Text Available Common agricultural birds are in decline, both in Europe and in North America. Evidence from Europe suggests that agricultural intensification and, for some species, the indirect effects of pesticides mediated through a loss of insect food resource is in part responsible. On a state-by-state basis for the conterminous Unites States (U.S., we looked at several agronomic variables to predict the number of grassland species increasing or declining according to breeding bird surveys conducted between 1980 and 2003. Best predictors of species declines were the lethal risk from insecticide use modeled from pesticide impact studies, followed by the loss of cropped pasture. Loss of permanent pasture or simple measures of agricultural intensification such as the proportion of land under crop or the proportion of farmland treated with herbicides did not explain bird declines as well. Because the proportion of farmland treated with insecticides, and more particularly the lethal risk to birds from the use of current insecticides feature so prominently in the best models, this suggests that, in the U.S. at least, pesticide toxicity to birds should be considered as an important factor in grassland bird declines.

  8. Population trends of North American sea ducks based on Christmas Bird Count and Breeding Bird Survey data

    Science.gov (United States)

    Niven, D.K.; Sauer, J.R.; Butcher, G.S.

    2005-01-01

    Due to the difficulty of conducting range-wide surveys of either breeding or wintering populations, few data are available to assess the population trends of sea ducks with confidence. We analyze sea duck data from the Audubon Christmas Bird Count (CBC) using hierarchical modeling methods that control for varying effort among circles and over time. These procedures allow us to assess early-winter relative density patterns among states and Bird Conservation Regions (BCRs) while also assessing trends in these regions and across the species North American range. Over the interval 1966-2003, continent-wide declines were observed in 1 of 11 species. Where sufficient data exist, we compare CBC results to estimates of population change derived from the USGS Breeding Bird Survey. The CBC does not effectively sample offshore populations of sea ducks; however, the CBC data can be used to assist in development of species-specific surveys, and CBC data can be used in combination with additional offshore sampling programs to better sample sea duck species.

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

    Science.gov (United States)

    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.

  10. Quantitative genetic variation in declining plant populations

    OpenAIRE

    Ellmer, Maarten

    2009-01-01

    The ecological and genetic effects of habitat fragmentation are an issue of major concern in current conservation biology. Habitat fragmentation results in smaller habitat areas and as a consequence smaller and more isolated populations. Many habitats have become fragmented through human activities such as forestry and agricultural development. In Sweden, for example, the area of species-rich, semi-natural grasslands has decreased by more than 90% since the 1870s. The aim of this thesis w...

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

    Science.gov (United States)

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

  12. Critical Decline of the Eastern Caribbean Sperm Whale Population.

    Science.gov (United States)

    Gero, Shane; 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.

  13. Population trends of forest birds at Hakalau Forest National Wildlife Refuge, Hawai'i

    Science.gov (United States)

    Camp, Richard J.; Pratt, Thane K.; Gorresen, P. Marcos; Jeffrey, John J.; Woodworth, Bethany L.

    2010-01-01

    The Hakalau Forest National Wildlife Refuge was established to protect native Hawaiian forest birds, particularly endangered species. Management for forest restoration on the refuge has consisted mainly of removing feral ungulates, controlling invasive alien plants, and reforesting former pastures. To assess effects of this habitat improvement for forest birds, we estimated density annually by distance sampling and examined population trends for native and alien passerines over the 21 years since the refuge was established. We examined long-term trends and recent short-term trajectories in three study areas: (1) reforested pastureland, (2) heavily grazed open forest that was recovering, and (3) lightly grazed closed forest that was relatively intact. Three species of native birds and two species of alien birds had colonized the reforested pasture and were increasing. In the open forest, densities of all eight native species were either stable or increasing. Long-term trends for alien birds were also generally stable or increasing. Worryingly, however, during the most recent 9 years, in the open forest trajectories of native species were decreasing or inconclusive, but in the reforested pasture they generally increased. The closed forest was surveyed in only the most recent 9 years, and trajectories of native species there were mixed. Overall, long-term population trends in Hakalau are stable or increasing, contrasting with declines in most other areas of Hawai'i over the same period. However, more recent mixed results may indicate emergent problems for this important bird area.

  14. Bird populations on the Island of Tinian: persistence despite wholesale loss of native forests

    Science.gov (United States)

    Camp, Richard J.; Amidon, Frederick A.; Marshall, Ann P.; Pratt, Thane K.

    2012-01-01

    Bird habitat on the island of Tinian, Mariana Islands, has been substantially altered, and only around 5% of the island has native forest today. The modern bird fauna is likely to be a subset of the original avifauna where only species tolerant to native forest loss and human disturbance have survived. Avian surveys were conducted on the island in 2008 by the U.S. Fish and Wildlife Service to provide current densities and abundances of the remaining species, and assess population trends using data collected from previous surveys. During the three surveys (1982, 1996, and 2008), 18 species were detected, and abundances and trends were assessed for 11 species. Five of the nine native species and one alien bird have increased since 1982. Three native birds—Mariana Fruit-Dove (Ptilinopusroseicapilla), Micronesian Honeyeater (Myzomela rubratra), and Tinian Monarch (Monarcha takatsukasae)—have decreased since 1982. Trends for the remaining two birds (one native and one alien) were considered relatively stable. Only five birds, including the Tinian Monarch, showed significant differences among regions of Tinian by year. Increased development on Tinian may result in increases in habitat clearing and expansion of human-dominated habitats, and declines in some bird populations would likely continue or be exacerbated with these actions. Expanded development activities on Tinian would also mean increased cargo movement between Guam and Tinian, elevating the probability of transporting the Brown Tree Snake (Boiga irregularis) to Tinian, which would lead to precipitous decreases and extinctions.

  15. Age-dependent terminal declines in reproductive output in a wild bird.

    Directory of Open Access Journals (Sweden)

    Martijn Hammers

    Full Text Available In many iteroparous species individual fitness components, such as reproductive output, first increase with age and then decline during late-life. However, individuals differ greatly in reproductive lifespan, but reproductive declines may only occur in the period just before their death as a result of an age-independent decline in physiological condition. To fully understand reproductive senescence it is important to investigate to what extent declines in late-life reproduction can be explained by age, time until death, or both. However, the study of late-life fitness performance in natural populations is challenging as the exact birth and death dates of individuals are often not known, and most individuals succumb to extrinsic mortality before reaching old age. Here, we used an exceptional long-term longitudinal dataset of individuals from a natural, closed, and predator-free population of the Seychelles warbler (Acrocephalus sechellensis to investigate reproductive output, both in relation to age and to the time until the death of an individual (reverse-age approach. We observed an initial age-dependent increase in reproductive output that was followed by a decline in old age. However, we found no significant decline in reproductive output in the years directly preceding death. Although post-peak reproductive output declined with age, this pattern differed between terminal and non-terminal reproductive attempts, and the age-dependence of the terminal breeding attempt explained much of the variation in age-specific reproductive output. In fact, terminal declines in reproductive output were steeper in very old individuals. These results indicate that not only age-dependent, but also age-independent factors, such as physiological condition, need to be considered to understand reproductive senescence in wild-living animals.

  16. Targeted reforestation could reverse declines in connectivity for understory birds in a tropical habitat corridor.

    Science.gov (United States)

    Fagan, Matthew E; DeFries, Ruth S; Sesnie, Steven E; Arroyo-Mora, J Pablo; Chazdon, Robin L

    2016-07-01

    Re-establishing connectivity between protected areas isolated by habitat clearing is a key conservation goal in the humid tropics. In northeastern Costa Rica, payments for environmental services (PES) and a government ban on deforestation have subsidized forest protection and reforestation in the San Juan-La Selva Biological Corridor (SJLSBC), resulting in a decline in mature forest loss and the expansion of tree plantations. We use field studies and graph models to assess how conservation efforts have altered functional connectivity over the last 25 years for four species of insectivorous understory birds. Field playback studies assessed how reforestation habitat quality affected the willingness of Myrmeciza exsul, Henicorhina leucosticta, Thamnophilus atrinucha, and Glyphorynchus spirurus to travel outside forest habitat for territorial defense. Observed travel distances were greatest in nonnative and native tree plantations with high understory stem density, regardless of overstory composition. In contrast, tree plantations with low stem density had travel responses comparable to open pasture for three of the four bird species. We modeled landscape connectivity for each species using graph models based on varying possible travel distances in tree plantations, gallery forests, and pastures. From 1986 to 2011, connectivity for all species declined in the SJLSBC landscape (5825 km 2 ) by 14% to 21% despite only a 4.9% net loss in forest area and the rapid expansion of tree plantations over 2% of the landscape. Plantation placement in the landscape limited their potential facilitation of connectivity because they were located either far from forest cover or within already contiguous forest areas. We mapped current connectivity bottlenecks and identified priority areas for future reforestation. We estimate that reforestation of priority areas could improve connectivity by 2% with only a 1% gain in forest cover, an impressive gain given the small area reforested

  17. Do Major Roads Reduce Gene Flow in Urban Bird Populations?

    Science.gov (United States)

    Zhang, Shuping; Suo, Mingli; Liu, Shenglin; Liang, Wei

    2013-01-01

    Background Although the negative effects of roads on the genetics of animal populations have been extensively reported, the question of whether roads reduce gene flow in volant, urban bird populations has so far not been addressed. In this study, we assess whether highways decreased gene flow and genetic variation in a small passerine bird, the tree sparrow (Passer montanus). Methodology We assessed genetic differences among tree sparrows (Passer montanus) sampled at 19 sites within Beijing Municipality, China, using 7 DNA microsatellites as genetic markers. Results AMOVA showed that genetic variation between sites, between urban and rural populations, and between opposite sides of the same highway, were very weak. Mantel tests on all samples, and on urban samples only, indicated that the age and number of highways, and the number of ordinary roads, were uncorrelated with genetic differences (FST) among tree sparrows from different urban sites. Birds sampled at urban sites had similar levels of genetic diversity to those at rural sites. There was, however, evidence of some weak genetic structure between urban sites. Firstly, there were significant genetic differences (FST) between birds from opposite sides of the same highway, but no significant FST values between those from sites that were not separated by highways. Secondly, birds from eleven urban sites had loci that significantly deviated from the Hardy–Weinberg equilibrium but no such deviation was found in birds from rural sites. Conclusion We cannot, therefore, conclusively reject the hypothesis that highways have no effect on the gene flow of tree sparrow populations. Furthermore, since the significance of these results may increase with time, we suggested that research on the influence of highways on gene flow in urban bird populations needs to be conducted over several decades. PMID:24204724

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  20. Time to extinction of bird populations

    NARCIS (Netherlands)

    Sæther, B-E.; Engen, S.; Møller, A.P.; Visser, M.E.; Matthysen, E.; Fiedler, W.; Lambrechts, M.M.; Becker, P.H.; Brommer, J.E.; Dickinson, J.; du Feu, C.; Gehlbach, F.R.; Merilä, J.; Rendell, W.; Robertson, R.J.; Thomson, D.L.; Török, J.

    2005-01-01

    The risk of extinction of populations has not previously been empirically related to parameters characterizing their population dynamics. To analyze this relationship, we simulated how the distribution of population dynamical characters changed as a function of time, in both the remaining and the

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

    Science.gov (United States)

    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 (DSR19) 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.

  2. Marine mammal population decline linked to obscured by-catch.

    Science.gov (United States)

    Meyer, Stefan; Robertson, Bruce C; Chilvers, B Louise; Krkošek, Martin

    2017-10-31

    Declines of marine megafauna due to fisheries by-catch are thought to be mitigated by exclusion devices that release nontarget species. However, exclusion devices may instead conceal negative effects associated with by-catch caused by fisheries (i.e., unobserved or discarded by-catch with low postrelease survival or reproduction). We show that the decline of the endangered New Zealand (NZ) sea lion ( Phocarctos hookeri ) is linked to latent levels of by-catch occurring in sub-Antarctic trawl fisheries. Exclusion devices have been used since 2001 but have not slowed or reversed population decline. However, 35% of the variability in NZ sea lion pup production is explained by latent by-catch, and the population would increase without this factor. Our results indicate that exclusion devices can obscure rather than alleviate fishery impacts on marine megafauna. Published under the PNAS license.

  3. Rapid population decline in red knots: fitness consequences of decreased refuelling rates and late arrival in Delaware Bay.

    Science.gov (United States)

    Baker, Allan J; González, Patricia M; Piersma, Theunis; Niles, Lawrence J; do Nascimento, Inês de Lima Serrano; Atkinson, Philip W; Clark, Nigel A; Minton, Clive D T; Peck, Mark K; Aarts, Geert

    2004-04-22

    Most populations of migrant shorebirds around the world are in serious decline, suggesting that vital condition-dependent rates such as fecundity and annual survival are being affected globally. A striking example is the red knot (Calidris canutus rufa) population wintering in Tierra del Fuego, which undertakes marathon 30,000 km hemispheric migrations annually. In spring, migrant birds forage voraciously on horseshoe crab eggs in Delaware Bay in the eastern USA before departing to breed in Arctic polar deserts. From 1997 to 2002 an increasing proportion of knots failed to reach threshold departure masses of 180-200 g, possibly because of later arrival in the Bay and food shortage from concurrent over-harvesting of crabs. Reduced nutrient storage, especially in late-arriving birds, possibly combined with reduced sizes of intestine and liver during refuelling, had severe fitness consequences for adult survival and recruitment of young in 2000-2002. From 1997 to 2002 known survivors in Delaware Bay were heavier at initial capture than birds never seen again, annual survival of adults decreased by 37% between May 2000 and May 2001, and the number of second-year birds in wintering flocks declined by 47%. Population size in Tierra del Fuego declined alarmingly from 51,000 to 27,000 in 2000-2002, seriously threatening the viability of this subspecies. Demographic modelling predicts imminent endangerment and an increased risk of extinction of the subspecies without urgent risk-averse management.

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

    Science.gov (United States)

    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

  5. Pesticides and Population Declines of California Alpine Frogs

    Science.gov (United States)

    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 ...

  6. European regional population decline and policy responses: three case studies

    NARCIS (Netherlands)

    Galjaard, R.; van Wissen, L.J.G.; van Dam, K.

    2012-01-01

    Universal processes related to the demographic transition to structural low fertility on the one hand, and economic geographic processes of concentration and urbanization on the other lead to regional population decline in most European countries. Due to this universal nature of the underlying

  7. The dynamics, transmission, and population impacts of avian malaria in native hawaiian birds: A modeling approach

    Science.gov (United States)

    Samuel, M.D.; Hobbelen, P.H.F.; Decastro, F.; Ahumada, J.A.; Lapointe, D.A.; Atkinson, C.T.; Woodworth, B.L.; Hart, P.J.; Duffy, D.C.

    2011-01-01

    We developed an epidemiological model of avian malaria (Plasmodium relictum) across an altitudinal gradient on the island of Hawaii that includes the dynamics of the host, vector, and parasite. This introduced mosquito-borne disease is hypothesized to have contributed to extinctions and major shifts in the altitudinal distribution of highly susceptible native forest birds. Our goal was to better understand how biotic and abiotic factors influence the intensity of malaria transmission and impact on susceptible populations of native Hawaiian forest birds. Our model illustrates key patterns in the malaria-forest bird system: high malaria transmission in low-elevation forests with minor seasonal or annual variation in infection;episodic transmission in mid-elevation forests with site-to-site, seasonal, and annual variation depending on mosquito dynamics;and disease refugia in high-elevation forests with only slight risk of infection during summer. These infection patterns are driven by temperature and rainfall effects on parasite incubation period and mosquito dynamics across an elevational gradient and the availability of larval habitat, especially in mid-elevation forests. The results from our model suggest that disease is likely a key factor in causing population decline or restricting the distribution of many susceptible Hawaiian species and preventing the recovery of other vulnerable species. The model also provides a framework for the evaluation of factors influencing disease transmission and alternative disease control programs, and to evaluate the impact of climate change on disease cycles and bird populations. ??2011 by the Ecological Society of America.

  8. Changes in bird populations on sample lowland English farms in relation to loss of hedgerows and other non-crop habitats.

    Science.gov (United States)

    Gillings, Simon; Fuller, Robert J

    1998-08-01

    Farmland bird population trends were examined on a sample of lowland English farms to assess the relative importance of habitat loss and habitat degradation. Data were extracted from 11 farms surveyed by territory mapping between 1966 and 1986 as part of the British Trust for Ornithology's Common Birds Census. The population size of 38 bird species was quantified for each farm in each year. The extents of five non-crop habitats were measured at 4-yearly intervals on each farm. The farms were selected because some had undergone extensive removal of non-crop habitats while others had undergone little or none. Although declines were commonest on farms where the severest habitat loss had taken place, we found no evidence that habitat loss was the main factor causing population declines: all 11 farms had significant numbers of declining species, even where habitat loss was minimal. Furthermore, general linear modelling found no significant effects of habitat loss on population trends and principal-components analysis found limited effects of habitat extent on community composition. These results suggest that habitat loss is of secondary importance in causing farmland bird population declines. We suggest that other processes, such as habitat degradation, may have caused a baseline population decline in at least 10 farmland bird species and that declines may have been exacerbated by localised habitat loss.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  11. Bird populations as sentinels of endocrine disrupting chemicals

    Directory of Open Access Journals (Sweden)

    Claudio Carere

    2010-03-01

    Full Text Available Exposure to endocrine disrupting chemicals (EDCs is a widespread phenomenon in nature. Although the mechanisms of action of EDCs are actively studied, the consequences of endocrine disruption (ED at the population level and the adaptations evolved to cope with chronic EDC exposure have been overlooked. Birds probably represent the animal taxon most successfully adapted to synanthropic life. Hence, birds share with humans a similar pattern of exposure to xenobiotics. In this article, we review case studies on patterns of behaviour that deviate from the expectation in bird species exposed to EDCs. We provide behavioural and ecological parameters to be used as endpoints of ED; methodological requirements and caveats based on species-specific life-history traits, behavioural repertoires, developmental styles, and possibility of captive breeding; a list of species that could be used as sentinels to assess the quality of man-made environment.

  12. Using Christmas Bird Count data in analysis of population change

    Science.gov (United States)

    Sauer, J.R.; Link, W.A.

    2002-01-01

    The scientific credibility of Christmas Bird Count (CBC) results depend on the development and implementation of appropriate methods of statistical analysis. The key to any successful analysis of CBC data is to begin with a careful review of how the limitations of the data are likely to influence the results of the analysis, then to choose methods of analysis that accommodate as much as possible the limitations of the survey. For our analyses of CBC data, we develop a flexible model for effort adjustment and use information from the data to guide the selection of the best model. We include geographic structuring to accommodate the regional variation in number of samples, use a model that allows for overdispersed poisson data appropriate for counts, and employ empirical Bayes procedures to accommodate differences in quality of information in regional summaries. This generalized linear model approach is very flexible, and can be applied to a variety of studies focused on factors influencing wintering bird populations. In particular, the model can be easily modified to contain covariates, allowing for assessment of associations between CBC counts and winter weather, disturbance, and a variety of other environmental factors. These new survey analysis methods have added value in that they provide insights into changes in survey design that can enhance the value of the information. The CBC has been extremely successful as a tool for increasing public interest in birding and bird conservation. Use of the information for bird conservation creates new demands on quality of information, and it is important to maintain a dialogue between users of the information, information needs for the analyses, and survey coordinators and participants. Our work as survey analysts emphasizes the value and limitations of existing data, and provides some indications of what features of the survey could be modified to make the survey a more reliable source of bird population data. Surveys

  13. Multiple stressor effects in relation to declining amphibian populations

    Science.gov (United States)

    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.

  14. Population trends of North American sea ducks as revealed by the Christmas Bird Count

    Science.gov (United States)

    Niven, D.K.; Sauer, J.R.; Butcher, G.S.

    2005-01-01

    Relative to other waterfowl, sea ducks are not well understood, yet evidence from a variety of analyses suggests that as many as 10 of the 15 species of North American sea ducks may be declining in population. However, because of the difficulty of conducting surveys of breeding populations and the lack of range-wide winter surveys, few data are available to assess the population trends of sea ducks with confidence. We analyze Audubon Christmas Bird Count data using hierarchical modeling methods that control for varying effort among circles and over time. These procedures allow us to assess early-winter relative density patterns among states and Bird Conservation Regions (BCRs) while also assessing trends in these regions and across the species North American range. Over the interval 1966 - 2003, continent-wide declines were observed in 1 of 11 species (the White-winged Scoter; -3.7%/yr). We compare CBC results to estimates of population change derived from the midwinter waterfowl survey conducted by the US Fish and Wildlife Service. The CBC does not effectively sample offshore populations of sea ducks; however, the CBC data can be used to assist in development of species-specific surveys, and CBC data can be used in combination with additional offshore sampling programs to better sample sea duck species.

  15. Assessing ecological correlates of marine bird declines to inform marine conservation

    Science.gov (United States)

    Vilchis, L Ignacio; Johnson, Christine K; Evenson, Joseph R; Pearson, Scott F; Barry, Karen L; Davidson, Peter; Raphael, Martin G; Gaydos, Joseph K

    2015-01-01

    Identifying drivers of ecosystem change in large marine ecosystems is central for their effective management and conservation. This is a sizable challenge, particularly in ecosystems transcending international borders, where monitoring and conservation of long-range migratory species and their habitats are logistically and financially problematic. Here, using tools borrowed from epidemiology, we elucidated common drivers underlying species declines within a marine ecosystem, much in the way epidemiological analyses evaluate risk factors for negative health outcomes to better inform decisions. Thus, we identified ecological traits and dietary specializations associated with species declines in a community of marine predators that could be reflective of ecosystem change. To do so, we integrated count data from winter surveys collected in long-term marine bird monitoring programs conducted throughout the Salish Sea—a transboundary large marine ecosystem in North America's Pacific Northwest. We found that decadal declines in winter counts were most prevalent among pursuit divers such as alcids (Alcidae) and grebes (Podicipedidae) that have specialized diets based on forage fish, and that wide-ranging species without local breeding colonies were more prone to these declines. Although a combination of factors is most likely driving declines of diving forage fish specialists, we propose that changes in the availability of low-trophic prey may be forcing wintering range shifts of diving birds in the Salish Sea. Such a synthesis of long-term trends in a marine predator community not only provides unique insights into the types of species that are at risk of extirpation and why, but may also inform proactive conservation measures to counteract threats—information that is paramount for species-specific and ecosystem-wide conservation. Evaluación de las Correlaciones Ecológicas de las Declinaciones de Aves Marinas para Informar a la Conservación Marina Resumen La

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

    Science.gov (United States)

    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

  17. Forest bird and fruit bat populations on Sarigan, Mariana Islands

    Science.gov (United States)

    Fancy, Steven G.; Craig, Robert J.; Kessler, Curt T.

    1999-01-01

    We conducted the first quantitative surveys of forest bird and bat populations on the uninhabited island of Sarigan, Commonwealth of the Northern Mariana Islands. Severe habitat degradation has occurred on Sarigan because of overgrazing by introduced goats and pigs. Planting of coconut palms (Cocos nucifera) for copra production has also eliminated much of the island’s native forest. We recorded five species of forest birds on Sarigan: Micronesian Honeyeater (Myzomela rubratra), Micronesian Megapode (Megapodius laperouse laperouse), Micronesian Starling (Aplonis opaca), Collared Kingfisher (Halcyon chloris), and White-throated Ground Dove (Gallicolumba xanthonura). Estimated population sizes (95% confidence interval) in 1997 were 1,821 (1,617–2,026) for Micronesian Honeyeater, 677 (545–810) for Micronesian Megapode, 497 (319–675) for Micronesian Starling, 107 (82–131) for Collared Kingfisher, and 170 (101–238) for Mariana Fruit Bat (Pteropus mariannus).

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

    Science.gov (United States)

    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.

  19. Flight distance and population trends in European breeding birds

    OpenAIRE

    Anders Pape Møller

    2008-01-01

    Flight distance reflects the risk that individual animals are willing to take when approached by a potential predator, as shown by a negative relationship between susceptibility to predation and flight distance. Species with long flight distances should more often suffer from disruption of their activities by potential predators, including humans, than species with short distances, resulting in declining reproductive success and hence declining population size of such species if disturbance h...

  20. Strategic Grassland Bird Conservation throughout the annual cycle: Linking policy alternatives, landowner decisions, and biological population outcomes

    Science.gov (United States)

    Drum, Ryan G.; Ribic, Christine; Koch, Katie; Lonsdorf, Eric V.; Grant, Edward C.; Ahlering, Marissa; Barnhill, Laurel; Dailey, Thomas; Lor, Socheata; Mueller, Connie; Pavlacky, D.C.; Rideout, Catherine; Sample, David W.

    2015-01-01

    Grassland bird habitat has declined substantially in the United States. Remaining grasslands are increasingly fragmented, mostly privately owned, and vary greatly in terms of habitat quality and protection status. A coordinated strategic response for grassland bird conservation is difficult, largely due to the scope and complexity of the problem, further compounded by biological, sociological, and economic uncertainties. We describe the results from a collaborative Structured Decision Making (SDM) workshop focused on linking social and economic drivers of landscape change to grassland bird population outcomes. We identified and evaluated alternative strategies for grassland bird conservation using a series of rapid prototype models. We modeled change in grassland and agriculture cover in hypothetical landscapes resulting from different landowner decisions in response to alternative socio-economic conservation policy decisions. Resulting changes in land cover at all three stages of the annual cycle (breeding, wintering, and migration) were used to estimate changes in grassland bird populations. Our results suggest that successful grassland bird conservation may depend upon linkages with ecosystem services on working agricultural lands and grassland-based marketing campaigns to engage the public. With further development, spatial models that link landowner decisions with biological outcomes can be essential tools for making conservation policy decisions. A coordinated non-traditional partnership will likely be necessary to clearly understand and systematically respond to the many conservation challenges facing grassland birds.

  1. Strategic Grassland Bird Conservation throughout the Annual Cycle: Linking Policy Alternatives, Landowner Decisions, and Biological Population Outcomes

    Science.gov (United States)

    Drum, Ryan G.; Ribic, Christine A.; Koch, Katie; Lonsdorf, Eric; Grant, Evan; Ahlering, Marissa; Barnhill, Laurel; Dailey, Thomas; Lor, Socheata; Mueller, Connie; Pavlacky, David C.; Rideout, Catherine; Sample, David

    2015-01-01

    Grassland bird habitat has declined substantially in the United States. Remaining grasslands are increasingly fragmented, mostly privately owned, and vary greatly in terms of habitat quality and protection status. A coordinated strategic response for grassland bird conservation is difficult, largely due to the scope and complexity of the problem, further compounded by biological, sociological, and economic uncertainties. We describe the results from a collaborative Structured Decision Making (SDM) workshop focused on linking social and economic drivers of landscape change to grassland bird population outcomes. We identified and evaluated alternative strategies for grassland bird conservation using a series of rapid prototype models. We modeled change in grassland and agriculture cover in hypothetical landscapes resulting from different landowner decisions in response to alternative socio-economic conservation policy decisions. Resulting changes in land cover at all three stages of the annual cycle (breeding, wintering, and migration) were used to estimate changes in grassland bird populations. Our results suggest that successful grassland bird conservation may depend upon linkages with ecosystem services on working agricultural lands and grassland-based marketing campaigns to engage the public. With further development, spatial models that link landowner decisions with biological outcomes can be essential tools for making conservation policy decisions. A coordinated non-traditional partnership will likely be necessary to clearly understand and systematically respond to the many conservation challenges facing grassland birds. PMID:26569108

  2. Strategic Grassland Bird Conservation throughout the Annual Cycle: Linking Policy Alternatives, Landowner Decisions, and Biological Population Outcomes.

    Science.gov (United States)

    Drum, Ryan G; Ribic, Christine A; Koch, Katie; Lonsdorf, Eric; Grant, Evan; Ahlering, Marissa; Barnhill, Laurel; Dailey, Thomas; Lor, Socheata; Mueller, Connie; Pavlacky, David C; Rideout, Catherine; Sample, David

    2015-01-01

    Grassland bird habitat has declined substantially in the United States. Remaining grasslands are increasingly fragmented, mostly privately owned, and vary greatly in terms of habitat quality and protection status. A coordinated strategic response for grassland bird conservation is difficult, largely due to the scope and complexity of the problem, further compounded by biological, sociological, and economic uncertainties. We describe the results from a collaborative Structured Decision Making (SDM) workshop focused on linking social and economic drivers of landscape change to grassland bird population outcomes. We identified and evaluated alternative strategies for grassland bird conservation using a series of rapid prototype models. We modeled change in grassland and agriculture cover in hypothetical landscapes resulting from different landowner decisions in response to alternative socio-economic conservation policy decisions. Resulting changes in land cover at all three stages of the annual cycle (breeding, wintering, and migration) were used to estimate changes in grassland bird populations. Our results suggest that successful grassland bird conservation may depend upon linkages with ecosystem services on working agricultural lands and grassland-based marketing campaigns to engage the public. With further development, spatial models that link landowner decisions with biological outcomes can be essential tools for making conservation policy decisions. A coordinated non-traditional partnership will likely be necessary to clearly understand and systematically respond to the many conservation challenges facing grassland birds.

  3. Strategic Grassland Bird Conservation throughout the Annual Cycle: Linking Policy Alternatives, Landowner Decisions, and Biological Population Outcomes.

    Directory of Open Access Journals (Sweden)

    Ryan G Drum

    Full Text Available Grassland bird habitat has declined substantially in the United States. Remaining grasslands are increasingly fragmented, mostly privately owned, and vary greatly in terms of habitat quality and protection status. A coordinated strategic response for grassland bird conservation is difficult, largely due to the scope and complexity of the problem, further compounded by biological, sociological, and economic uncertainties. We describe the results from a collaborative Structured Decision Making (SDM workshop focused on linking social and economic drivers of landscape change to grassland bird population outcomes. We identified and evaluated alternative strategies for grassland bird conservation using a series of rapid prototype models. We modeled change in grassland and agriculture cover in hypothetical landscapes resulting from different landowner decisions in response to alternative socio-economic conservation policy decisions. Resulting changes in land cover at all three stages of the annual cycle (breeding, wintering, and migration were used to estimate changes in grassland bird populations. Our results suggest that successful grassland bird conservation may depend upon linkages with ecosystem services on working agricultural lands and grassland-based marketing campaigns to engage the public. With further development, spatial models that link landowner decisions with biological outcomes can be essential tools for making conservation policy decisions. A coordinated non-traditional partnership will likely be necessary to clearly understand and systematically respond to the many conservation challenges facing grassland birds.

  4. Global population collapse in a superabundant migratory bird and illegal trapping in China.

    Science.gov (United States)

    Kamp, Johannes; Oppel, Steffen; Ananin, Alexandr A; Durnev, Yurii A; Gashev, Sergey N; Hölzel, Norbert; Mishchenko, Alexandr L; Pessa, Jorma; Smirenski, Sergey M; Strelnikov, Evgenii G; Timonen, Sami; Wolanska, Kolja; Chan, Simba

    2015-12-01

    Persecution and overexploitation by humans are major causes of species extinctions. Rare species, often confined to small geographic ranges, are usually at highest risk, whereas extinctions of superabundant species with very large ranges are rare. The Yellow-breasted Bunting (Emberiza aureola) used to be one of the most abundant songbirds of the Palearctic, with a very large breeding range stretching from Scandinavia to the Russian Far East. Anecdotal information about rapid population declines across the range caused concern about unsustainable trapping along the species' migration routes. We conducted a literature review and used long-term monitoring data from across the species' range to model population trend and geographical patterns of extinction. The population declined by 84.3-94.7% between 1980 and 2013, and the species' range contracted by 5000 km. Quantitative evidence from police raids suggested rampant illegal trapping of the species along its East Asian flyway in China. A population model simulating an initial harvest level of 2% of the population, and an annual increase of 0.2% during the monitoring period produced a population trajectory that matched the observed decline. We suggest that trapping strongly contributed to the decline because the consumption of Yellow-breasted Bunting and other songbirds has increased as a result of economic growth and prosperity in East Asia. The magnitude and speed of the decline is unprecedented among birds with a comparable range size, with the exception of the Passenger Pigeon (Ectopistes migratorius), which went extinct in 1914 due to industrial-scale hunting. Our results demonstrate the urgent need for an improved monitoring of common and widespread species' populations, and consumption levels throughout East Asia. © 2015 Society for Conservation Biology.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. The reproduction of sea birds of La Hague and of the Nez-de-Jobourg: The search for reasons of decline (Manche)

    International Nuclear Information System (INIS)

    James, Jean-Baptiste

    2001-11-01

    Since 1965, the site of the Nez-de-Jobourg, in the Manche district and at the vicinity of the La Hague plant, has been a site of ornithological follow-up, notably because it harbours different population of nesting sea birds. Since 1990, it has been noticed that the population of European shags has been keeping on decreasing, with abnormally low birth rate, while the European herring gull has totally disappeared. If the relationship between this decline and the releases of the La Hague nuclear waste processing plant is easily and quickly suspected, other reasons are also plausible. The authors report a study of this decline and an investigation of its possible origins. After a presentation of the site, of its status regarding hunting and specie protection, and a presentation of other close sites (small islands, bay), the report addresses the case of the European shag. It gives information on its biology, characteristics, location and population, reproduction sites and nesting cycle. It presents the method adopted to test the various hypotheses of origin of the noticed decline: contamination by radioactive materials or by chemical substances, problems of disturbance by fishers, tourists or others, problems of predation, parasitism or lack of food resources. Samplings have been performed within the studied site and also within reference sites located some miles away. Based on data and observations, hypotheses are then discussed. An analytical report of measurement of artificial radio-elements performed by gamma spectrometry is provided

  8. Opportunities within the Revised EU Common Agricultural Policy to Address the Decline of Farmland Birds: An Irish Perspective

    Directory of Open Access Journals (Sweden)

    Daire Ó hUallacháin

    2015-08-01

    Full Text Available The loss of global biological diversity continues despite on-going conservation efforts. Agriculture is the major terrestrial land use in Europe and any conservation efforts to protect biological diversity must address sustainable use of these food production systems. Using Ireland, within the European Union policy framework, as an example, the declines in farmland birds are discussed. The opportunities afforded to farmland bird conservation as a result of the recent reform to the Common Agricultural Policy (CAP are outlined. The potential for revised and refined CAP, specifically agri-environment schemes, to deliver benefits for biodiversity and for farmland bird species within Irish agricultural ecosystems is explored. Despite all the efforts to date and the significant resources invested in implementing agri-environment measures and schemes, few attempts have been made to collect monitoring and surveillance data with which to quantitatively assess the effectiveness of schemes, and measures that are designed to assist in the recovery of farmland biodiversity, including bird species, in Ireland.

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

    Directory of Open Access Journals (Sweden)

    Nicola Saino

    Full Text Available 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

  10. Age-dependent terminal declines in reproductive output in a wild bird

    NARCIS (Netherlands)

    Hammers, Martijn; Richardson, David S.; Burke, Terry; Komdeur, Jan

    2012-01-01

    In many iteroparous species individual fitness components, such as reproductive output, first increase with age and then decline during late-life. However, individuals differ greatly in reproductive lifespan, but reproductive declines may only occur in the period just before their death as a result

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

    Directory of Open Access Journals (Sweden)

    Mara E Erickson

    Full Text Available 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.

  12. Is the Bird Population in the Hadejia-Nguru Wetlands under Threat ...

    African Journals Online (AJOL)

    Anthropogenic disturbances have been found to be one of the key drivers of changes in bird populations as observed with dramatic consequences among the bird assemblages of Hadejia-Nguru Ramsar Wetland and elsewhere globally. We assessed the effects of farming, fishing, and grazing on bird species richness and ...

  13. Comparative metatranscriptomics reveals decline of a neustonic planktonic population

    KAUST Repository

    Mojib, Nazia

    2016-10-20

    The neuston layer in tropical seas provides a good model to study the effects of increased levels of different stressors (e.g., temperature, ultraviolet radiation and Trichodesmium blooms). Here, we use a comparative in situ metatranscriptomics approach to reveal the functional genomic composition of metabolically active neustonic mesozooplankton community in response to the summer conditions in the Red Sea. The neustonic population exhibited changes in composition and abundance with a significant decline in copepods and appendicularia in July, when Trichodesmium cells were more abundant along with high temperatures and UV-B radiation. Nearly 23,000 genes were differentially expressed at the community level when the metatranscriptomes of the neustonic zooplankton were compared in April, July, and October. On a wider Phylum level, the genes related to oxidative phosphorylation, carbon, nucleotides, amino acids, and lipids were significantly overrepresented in both arthropods and chordates in April and October. On organism level for copepods, expression of genes responsive to oxidative stress, defense against bacteria, immune response, and virus reproduction were increased along with the observed increased appearance of copepod carcasses in the samples collected during July. The differences in expression correspond either to secondary effects of the Trichodesmium bloom or more likely to the increased UV-B radiation in July. Given the dearth of information on the zooplankton gene expression in response to environmental stimuli, our study provides the first transcriptome landscape of the mesozooplankton community during a period of increased mortality of the copepod and appendicularia population.

  14. Estimation of contemporary effective population size and population declines using RAD sequence data.

    Science.gov (United States)

    Nunziata, Schyler O; Weisrock, David W

    2018-03-01

    Large genomic data sets generated with restriction site-associated DNA sequencing (RADseq), in combination with demographic inference methods, are improving our ability to gain insights into the population history of species. We used a simulation approach to examine the potential for RADseq data sets to accurately estimate effective population size (N e ) over the course of stable and declining population trends, and we compare the ability of two methods of analysis to accurately distinguish stable from steadily declining populations over a contemporary time scale (20 generations). Using a linkage disequilibrium-based analysis, individual sampling (i.e., n ≥ 30) had the greatest effect on N e estimation and the detection of population size declines, with declines reliably detected across scenarios ~10 generations after they began. Coalescent-based inference required fewer sampled individuals (i.e., n = 15), and instead was most influenced by the size of the SNP data set, with 25,000-50,000 SNPs required for accurate detection of population trends and at least 20 generations after decline began. The number of samples available and targeted number of RADseq loci are important criteria when choosing between these methods. Neither method suffered any apparent bias due to the effects of allele dropout typical of RAD data. With an understanding of the limitations and biases of these approaches, researchers can make more informed decisions when designing their sampling and analyses. Overall, our results reveal that demographic inference using RADseq data can be successfully applied to infer recent population size change and may be an important tool for population monitoring and conservation biology.

  15. Bird on the wire: Landscape planning considering costs and benefits for bird populations coexisting with power lines.

    Science.gov (United States)

    D'Amico, Marcello; Catry, Inês; Martins, Ricardo C; Ascensão, Fernando; Barrientos, Rafael; Moreira, Francisco

    2018-02-24

    Power-line grids are increasingly expanding worldwide, as well as their negative impacts on avifauna, namely the direct mortality through collision and electrocution, the reduction of breeding performance, and the barrier effect. On the other hand, some bird species can apparently benefit from the presence of power lines, for example perching for hunting purposes or nesting on electricity towers. In this perspective essay, we reviewed the scientific literature on both costs and benefits for avifauna coexisting with power lines. Overall, we detected a generalized lack of studies focusing on these costs or benefits at a population level. We suggest that a switch in research approach to a larger spatio-temporal scale would greatly improve our knowledge about the actual effects of power lines on bird populations. This research approach would facilitate suitable landscape planning encompassing both mitigation of costs and promotion of benefits for bird populations coexisting with power lines. For example, the strategic route planning of electricity infrastructures would limit collision risk or barrier effects for threatened bird populations. Concurrently, this strategic route planning would promote the range expansion of threatened populations of other bird species, by providing nesting structures in treeless but potentially suitable landscapes. We suggest establishing a collaborative dialogue among the scientific community, governments, and electricity companies, with the aim to produce a win-win scenario in which both biodiversity conservation and infrastructure development are integrated in a common strategy.

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

    Science.gov (United States)

    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...

  17. Declines in oil-rates of stranded birds in the North Sea highlight spatial patterns in reductions of chronic oil pollution.

    Science.gov (United States)

    Camphuysen, Kees C J

    2010-08-01

    Strandings of oiled seabirds are used to signal the problem of chronic oil pollution. Species-specific oil rates reflect the risk for marine birds to become oiled at sea. High oil rates were characteristic for seabirds common in areas with frequent oil spills; low oil rates for birds wintering away from the busiest shipping lanes. Declining trends in oil-rates were found, reflecting a reduction in the amount of oil intentionally discharged over the past 50years. Spatial patterns in the risk to become oiled could be identified, when the winter distribution patterns of the affected birds were incorporated in the analysis. Declines in oil rates were most pronounced in coastal birds. These trends were consistent with tendencies to police nearshore waters more effectively than offshore waters. While levels of chronic oil pollution are much reduced, future emphasis should be to reduce chronic oiling more effectively in offshore waters. Copyright 2010 Elsevier Ltd. All rights reserved.

  18. Reasons for the decline in bird numbers breeding near the Ravenglass Estuary

    International Nuclear Information System (INIS)

    Anderson, N.; Evans, P.R.

    1987-07-01

    Black-headed Gulls breeding at Ravenglass (and at other coastal sites in Cumbria) fed exclusively inland during the breeding season and so could not have acquired any radionuclide contaminants present in the estuarine muds and invertebrates. They, and two other ground-nesting bird species have suffered severe disturbance and predation by foxes at Ravenglass in recent years. In contrast, the Shelduck, which nests in holes (and so does not suffer fox predation) but feeds at Ravenglass on estuarine invertebrates, has bred successfully. Levels of heavy metal contaminants in gull tissues and eggs were too low to have caused the observed breeding failures at Ravenglass. Gulls feeding on the estuary before the breeding season, but which then moved to other (inland) breeding sites, nested successfully. (author)

  19. Oak Ridge Reservation Bird Records and Population Trends

    Energy Technology Data Exchange (ETDEWEB)

    Roy, W. Kelly [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Giffen, Neil R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wade, Murray [CDM Smith, Inc., Knoxville, TN (United States); Haines, Angelina [Xcel Engineering, Inc., Oak Ridge, TN (United States); Evans, James W. [Tennessee Wildlife Resources Agency, Nashville, TN (United States); Jett, Robert Trent [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-11-01

    Bird data have been collected through surveys, environmental assessments, and other observations for decades in the Oak Ridge National Environmental Research Park, located on the US Department of Energy s Oak Ridge Reservation (ORR) in East Tennessee. Birds were recorded in a variety of habitats, including wetlands, interior forests, grasslands, ponds, corridors, forest edges, and more. Most of the information was gathered from waterfowl surveys conducted from 1990 to 2008, from Partners in Flight (PIF) breeding bird surveys conducted from 1995 to 2013, and from past publications and research on Reservation birds. We have also included our own observations and, in a few instances, credible observations of ORR birds of which we have been made aware through eBird or discussions with area ornithologists and bird watchers. For the period 1950 2014, we were able to document 228 species of birds on the ORR. Several of these species are known from historic records only, while others were not known to have ever occurred on the Reservation until recently. This report does not include PIF breeding bird data from the 2014 season or any records after July 2014. Twenty-two species approximately 10% of the total number of species observed have state-listed status in Tennessee as endangered, threatened, or in need of management. Of the 228 species we documented, 120 are believed to be breeding birds on the ORR.

  20. Oak Ridge Reservation Bird Records and Population Trends

    Energy Technology Data Exchange (ETDEWEB)

    Roy, W. K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Giffen, N. R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wade, M. C. [CDM Smith (United States); Haines, A. M. [Xcel Engineering, Inc.(United States); Evans, J. W. [Tennessee WIldlife Resources Agency (WRA), Nashville, TN (United States); Jett, R. T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-09-01

    Bird data have been collected through surveys, environmental assessments, and other observations for decades in the Oak Ridge National Environmental Research Park, located on the US Department of Energy’s Oak Ridge Reservation (ORR) in East Tennessee. Birds were recorded in a variety of habitats, including wetlands, interior forests, grasslands, ponds, corridors, forest edges, and more. Most of the information was gathered from waterfowl surveys conducted from 1990 to 2008, from Partners in Flight (PIF) breeding bird surveys conducted from 1995 to 2013, and from past publications and research on Reservation birds. We have also included our own observations and, in a few instances, credible observations of ORR birds of which we have been made aware through eBird or discussions with area ornithologists and bird watchers. For the period 1950-2014, we were able to document 228 species of birds on the ORR. Several of these species are known from historic records only, while others were not known to have ever occurred on the Reservation until recently. This report does not include PIF breeding bird data from the 2014 season or any records after July 2014. Twenty-two species--approximately 10% of the total number of species observed--have state-listed status in Tennessee as endangered, threatened, or in need of management. Of the 228 species we documented, 120 are believed to be breeding birds on the ORR.

  1. Disentangling the relative importance of changes in climate and land-use intensity in driving recent bird population trends.

    Directory of Open Access Journals (Sweden)

    Sarah M Eglington

    Full Text Available Threats to biodiversity resulting from habitat destruction and deterioration have been documented for many species, whilst climate change is regarded as increasingly impacting upon species' distribution and abundance. However, few studies have disentangled the relative importance of these two drivers in causing recent population declines. We quantify the relative importance of both processes by modelling annual variation in population growth of 18 farmland bird species in the UK as a function of measures of land-use intensity and weather. Modelled together, both had similar explanatory power in accounting for annual fluctuations in population growth. When these models were used to retrodict population trends for each species as a function of annual variation in land-use intensity and weather combined, and separately, retrodictions incorporating land-use intensity were more closely linked to observed population trends than retrodictions based only on weather, and closely matched the UK farmland bird index from 1970 onwards. Despite more stable land-use intensity in recent years, climate change (inferred from weather trends has not overtaken land-use intensity as the dominant driver of bird populations.

  2. On the importance of controlling for effort in analysis of count survey data: Modeling population change from Christmas Bird Count data

    Science.gov (United States)

    Link, W.A.; Sauer, J.R.; Helbig, Andreas J.; Flade, Martin

    1999-01-01

    Count survey data are commonly used for estimating temporal and spatial patterns of population change. Since count surveys are not censuses, counts can be influenced by 'nuisance factors' related to the probability of detecting animals but unrelated to the actual population size. The effects of systematic changes in these factors can be confounded with patterns of population change. Thus, valid analysis of count survey data requires the identification of nuisance factors and flexible models for their effects. We illustrate using data from the Christmas Bird Count (CBC), a midwinter survey of bird populations in North America. CBC survey effort has substantially increased in recent years, suggesting that unadjusted counts may overstate population growth (or understate declines). We describe a flexible family of models for the effect of effort, that includes models in which increasing effort leads to diminishing returns in terms of the number of birds counted.

  3. Current land bird distribution and trends in population abundance between 1982 and 2012 on Rota, Mariana Islands

    Science.gov (United States)

    Camp, Richard J.; Brinck, Kevin W.; Gorresen, P. Marcos; Amidon, Fred A.; Radley, Paul M.; Berkowitz, S. Paul; Banko, Paul C.

    2015-01-01

    The western Pacific island of Rota is the fourth largest human-inhabited island in the Mariana archipelago and designated an Endemic Bird Area. Between 1982 and 2012, 12 point-transect distance-sampling surveys were conducted to assess bird population status. Surveys did not consistently sample the entire island; thus, we used a ratio estimator to estimate bird abundances in strata not sampled during every survey. Trends in population size were reliably estimated for 11 of 13 bird species, and 7 species declined over the 30-y time series, including the island collared-dove Streptopelia bitorquata, white-throated ground-dove Gallicolumba xanthonura, Mariana fruit-dove Ptilinopus roseicapilla, collared kingfisher Todiramphus chloris orii, Micronesian myzomela Myzomela rubratra, black drongo Dicrurus macrocercus, and Mariana crow Corvus kubaryi. The endangered Mariana crow (x̄  =  81 birds, 95% CI 30–202) declined sharply to fewer than 200 individuals in 2012, down from 1,491 birds in 1982 (95% CI  =  815–3,115). Trends increased for white tern Gygis alba, rufous fantail Rhipidura rufifrons mariae, and Micronesian starling Aplonis opaca. Numbers of the endangered Rota white-eye Zosterops rotensis declined from 1982 to the late 1990s but returned to 1980s levels by 2012, resulting in an overall stable trend. Trends for the yellow bittern Ixobrychus sinensis were inconclusive. Eurasian tree sparrow Passer montanus trends were not assessed; however, their numbers in 1982 and 2012 were similar. Occupancy models of the 2012 survey data revealed general patterns of land cover use and detectability among 12 species that could be reliably modeled. Occupancy was not assessed for the Eurasian tree sparrow because of insufficient detections. Based on the 2012 survey, bird distribution and abundance across Rota revealed three general patterns: 1) range restriction, including Mariana crow, Rota white-eye, and Eurasian tree sparrow; 2) widespread distribution, low

  4. Aspects of population dynamics and feeding by piscivorous birds in ...

    African Journals Online (AJOL)

    Breaching events were associated with a change in feeding groups from waders to pursuit feeders, and a decrease in total bird numbers, most likely due to loss of potential littoral zone foraging habitat for waders resulting from reduced water levels. The highest bird numbers were recorded in winter reflecting the migration of ...

  5. Global change and the distributional dynamics of migratory bird populations wintering in Central America.

    Science.gov (United States)

    La Sorte, Frank A; Fink, Daniel; Blancher, Peter J; Rodewald, Amanda D; Ruiz-Gutierrez, Viviana; Rosenberg, Kenneth V; Hochachka, Wesley M; Verburg, Peter H; Kelling, Steve

    2017-12-01

    Understanding the susceptibility of highly mobile taxa such as migratory birds to global change requires information on geographic patterns of occurrence across the annual cycle. Neotropical migrants that breed in North America and winter in Central America occur in high concentrations on their non-breeding grounds where they spend the majority of the year and where habitat loss has been associated with population declines. Here, we use eBird data to model weekly patterns of abundance and occurrence for 21 forest passerine species that winter in Central America. We estimate species' distributional dynamics across the annual cycle, which we use to determine how species are currently associated with public protected areas and projected changes in climate and land-use. The effects of global change on the non-breeding grounds is characterized by decreasing precipitation, especially during the summer, and the conversion of forest to cropland, grassland, or peri-urban. The effects of global change on the breeding grounds are characterized by increasing winter precipitation, higher temperatures, and the conversion of forest to peri-urban. During spring and autumn migration, species are projected to encounter higher temperatures, forests that have been converted to peri-urban, and increased precipitation during spring migration. Based on current distributional dynamics, susceptibility to global change is characterized by the loss of forested habitats on the non-breeding grounds, warming temperatures during migration and on the breeding grounds, and declining summer rainfall on the non-breeding grounds. Public protected areas with low and medium protection status are more prevalent on the non-breeding grounds, suggesting that management opportunities currently exist to mitigate near-term non-breeding habitat losses. These efforts would affect more individuals of more species during a longer period of the annual cycle, which may create additional opportunities for species to

  6. CAUSES AND CONSEQUENCES OF REGIONAL POPULATION DECLINE FOR PRIMARY SCHOOLS

    NARCIS (Netherlands)

    Haartsen, Tialda; Van Wissen, Leo

    During the past few years, the Dutch education system has been confronted with a sharp decline in the number of pupils. Especially in rural villages, inhabitants fear for the closure of their local primary school, which is perceived as a very negative development for local village life. This paper

  7. Reliability of genetic bottleneck tests for detecting recent population declines

    NARCIS (Netherlands)

    Peery, M. Zachariah; Kirby, Rebecca; Reid, Brendan N.; Stoelting, Ricka; Doucet-Beer, Elena; Robinson, Stacie; Vasquez-Carrillo, Catalina; Pauli, Jonathan N.; Palsboll, Per J.

    The identification of population bottlenecks is critical in conservation because populations that have experienced significant reductions in abundance are subject to a variety of genetic and demographic processes that can hasten extinction. Genetic bottleneck tests constitute an appealing and

  8. Riparian bird density decline in response to biocontrol of Tamarix from riparian ecosystems along the Dolores River in SW Colorado, USA

    Science.gov (United States)

    Darrah, Abigail J.; van Riper, Charles

    2018-01-01

    Biocontrol of invasive tamarisk (Tamarix spp.) in the arid Southwest using the introduced tamarisk beetle (Diorhabda elongata) has been hypothesized to negatively affect some breeding bird species, but no studies to date have documented the effects of beetle-induced defoliation on riparian bird abundance. We assessed the effects of tamarisk defoliation by monitoring defoliation rates, changes in vegetation composition, and changes in density of six obligate riparian breeding bird species at two sites along the Dolores River in Colorado following the arrival of tamarisk beetles. We conducted bird point counts from 2010 to 2014 and modeled bird density as a function of native vegetation density and extent of defoliation using hierarchical distance sampling. Maximum annual defoliation decreased throughout the study period, peaking at 32–37% in 2009–2010 and dropping to 0.5–15% from 2011–2014. Stem density of both tamarisk and native plants declined throughout the study period until 2014. Density of all bird species declined throughout most of the study, with Song Sparrow disappearing from the study sites after 2011. Blue Grosbeak, Yellow-breasted Chat, and Yellow Warbler densities were negatively related to defoliation in the previous year, while Lazuli Bunting exhibited a positive relationship with defoliation. These findings corroborate earlier predictions of species expected to be sensitive to defoliation as a result of nest site selection. Tamarisk defoliation thus had short-term negative impacts on riparian bird species; active restoration may be needed to encourage the regrowth of native riparian vegetation, which in the longer-term may result in increased riparian bird density.

  9. Riparian bird density decline in response to biocontrol of Tamarix from riparian ecosystems along the Dolores River in SW Colorado, USA

    Science.gov (United States)

    Darrah, Abigail J.; van Riper, Charles

    2017-01-01

    Biocontrol of invasive tamarisk (Tamarix spp.) in the arid Southwest using the introduced tamarisk beetle (Diorhabda elongata) has been hypothesized to negatively affect some breeding bird species, but no studies to date have documented the effects of beetle-induced defoliation on riparian bird abundance. We assessed the effects of tamarisk defoliation by monitoring defoliation rates, changes in vegetation composition, and changes in density of six obligate riparian breeding bird species at two sites along the Dolores River in Colorado following the arrival of tamarisk beetles. We conducted bird point counts from 2010 to 2014 and modeled bird density as a function of native vegetation density and extent of defoliation using hierarchical distance sampling. Maximum annual defoliation decreased throughout the study period, peaking at 32–37% in 2009–2010 and dropping to 0.5–15% from 2011–2014. Stem density of both tamarisk and native plants declined throughout the study period until 2014. Density of all bird species declined throughout most of the study, with Song Sparrow disappearing from the study sites after 2011. Blue Grosbeak, Yellow-breasted Chat, and Yellow Warbler densities were negatively related to defoliation in the previous year, while Lazuli Bunting exhibited a positive relationship with defoliation. These findings corroborate earlier predictions of species expected to be sensitive to defoliation as a result of nest site selection. Tamarisk defoliation thus had short-term negative impacts on riparian bird species; active restoration may be needed to encourage the regrowth of native riparian vegetation, which in the longer-term may result in increased riparian bird density.

  10. Diagnosing mechanisms of decline and planning for recovery of an endangered brown bear (Ursus arctos population.

    Directory of Open Access Journals (Sweden)

    Guillaume Chapron

    Full Text Available 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.

  11. Increasing population and declining biological resources in the ...

    Indian Academy of Sciences (India)

    Biodiversity; global change; globalization; population and land use; sustainable landscape management; traditional ecological management. Abstract. 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 ...

  12. Monitoring low density populations: a perspective on what level of population decline we can truly detect

    Directory of Open Access Journals (Sweden)

    Lurz, P. W. W.

    2008-06-01

    Full Text Available Monitoring of mammal species is an important part in detecting changes in their status. Efforts are based on a variety of direct and indirect methods and many low density populations are monitored through field signs. We present data on the endangered European red squirrel from Kidland Forest in the UK. We used cone transects to both record changes in seed availability and to monitor population trends. We examined the difficulty of accurately detecting population change when populations are low and field signs are patchily distributed. Current efforts would be sufficient to detect significant population declines of 50-75% in years with a modest squirrel population but not when they fall below one squirrel for every 20 ha of forest. The findings emphasise that monitoring aims have to be clearly defined with an awareness and understanding of what level of change the adopted methodological approach can reliably detect. We propose that mammal monitoring schemes need to be based on a pilot scheme to determine effect size and planned accordingly.

  13. The interacting effects of forestry and climate change on the demography of a group-living bird population.

    Science.gov (United States)

    Layton-Matthews, Kate; Ozgul, Arpat; Griesser, Michael

    2018-03-01

    Anthropogenic degradation of natural habitats is a global driver of wildlife population declines. Local population responses to such environmental perturbations are generally well understood, but in socially structured populations, interactions between environmental and social factors may influence population responses. Thus, understanding how habitat degradation affects the dynamics of these populations requires simultaneous consideration of social and environmental mechanisms underlying demographic responses. Here we investigated the effect of habitat degradation through commercial forestry on spatiotemporal dynamics of a group-living bird, the Siberian jay, Perisoreus infaustus, in boreal forests of northern Sweden. We assessed the interacting effects of forestry, climate and population density on stage-specific, seasonal life-history rates and population dynamics, using long-term, individual-based demographic data from 70 territories in natural and managed forests. Stage-specific survival and reproductive rates, and consequently population growth, were lower in managed forests than in natural forests. Population growth was most sensitive to breeder survival and was more sensitive to early dispersing juveniles than those delaying dispersal. Forestry decreased population growth in managed forests by reducing reproductive success and breeder survival. Increased snow depth improved winter survival, and warmer spring temperatures enhanced reproductive success, particularly in natural forests. Population growth was stable in natural forests but it was declining in managed forests, and this difference accelerated under forecasted climate scenarios. Thus, climatic change could exacerbate the rate of forestry-induced population decline through reduced snow cover in our study species, and in other species with similar life-history characteristics and habitat requirements.

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

    Science.gov (United States)

    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…

  15. Population densities and community structure of birds in riverine ...

    African Journals Online (AJOL)

    In terms of diet, the majority of birds were insectivorous, followed by the mixed diet category. Frugivores, though few in number, contributed significantly to biomass. Granivorous species and raptors contributed insignificantly. The avifauna of riverine forest in Swaziland is compared with similar habitats in southern Africa and ...

  16. Is Declining malaria vector population in Africa a result of intervention Measures or sampling tools inefficiency?

    Directory of Open Access Journals (Sweden)

    Eliningaya Kweka

    2013-01-01

    Full Text Available Recent entomological surveys have shown a declining trend of malaria vector population in sub-Saharan Africa and the observation have beenassociated with the scale-up and intensive use of malaria intervention measures such as insecticides treated nets and insecticide residual sprays.However, little is known on the contribution of the mosquito sampling tools inefficiency on the declining trends of malaria vector population. Inthis commentary paper, we explore the possibility of contribution of mosquito sampling tools’ inefficiency to the observed declining trends ofmalaria vector population in Africa.

  17. Increasing population and declining biological resources in the ...

    Indian Academy of Sciences (India)

    Unknown

    Biodiversity; global change; globalization; population and land use; sustainable landscape management; traditional ecological management ... biodiversity on which they are dependant for their livelihood, there is an urgent need to explore additional pathways for ...... the upland central region of Mexico, as a response to.

  18. Increasing population and declining biological resources in the ...

    Indian Academy of Sciences (India)

    Unknown

    In the context of over-consumption of natural resources in the name of development and rapid industrialization by a small section of the human ... rise in the world population which started off at a modest rate of under 0⋅5% rose to about .... beings since a variety of other factors such as trade, technology and consumption ...

  19. Nigeria's Population Policy and Future Fertility Decline | Mba ...

    African Journals Online (AJOL)

    Paramount among these is the intention to reduce total fertility rate (TFR) to 4, raise the use of family planning methods to 80 per cent, and raise mean age at first marriage to 18 years, by the year 2000. However ... It is, therefore, needful to revisit the demographic targets of the population policy of Nigeria. Key Words: Nigeria ...

  20. Impact of Spring Bird Migration on the Range Expansion of Ixodes scapularis Tick Population.

    Science.gov (United States)

    Wu, Xiaotian; Röst, Gergely; Zou, Xingfu

    2016-01-01

    Many observational studies suggest that seasonal migratory birds play an important role in spreading Ixodes scapularis, a vector of Lyme disease, along their migratory flyways, and they are believed to be responsible for geographic range expansion of I. scapularis in Canada. However, the interplay between the dynamics of I. scapularis on land and migratory birds in the air is not well understood. In this study, we develop a periodic delay meta-population model which takes into consideration the local landscape for tick reproduction within patches and the times needed for ticks to be transported by birds between patches. Assuming that the tick population is endemic in the source region, we find that bird migration may boost an already established tick population at the subsequent region and thus increase the risk to humans, or bird migration may help ticks to establish in a region where the local landscape is not appropriate for ticks to survive in the absence of bird migration, imposing risks to public health. This theoretical study reveals that bird migration plays an important role in the geographic range expansion of I. scapularis, and therefore our findings may suggest some strategies for Lyme disease prevention and control.

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

    Directory of Open Access Journals (Sweden)

    Jiří Flousek

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

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

    Directory of Open Access Journals (Sweden)

    David Anchundia

    2014-06-01

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

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

    Science.gov (United States)

    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. Declines in moth populations stress the need for conserving dark nights

    NARCIS (Netherlands)

    Langevelde, van Frank; Braamburg-Annegarn, Marijke; Huigens, Martinus E.; Groendijk, Rob; Poitevin, Olivier; Deijk, van Jurriën R.; Ellis, Willem N.; Grunsven, van Roy H.A.; Vos, de Rob; Vos, Rutger A.; Franzén, Markus; WallisDeVries, Michiel F.

    2018-01-01

    Given the global continuous rise, artificial light at night is often considered a driving force behind moth population declines. Although negative effects on individuals have been shown, there is no evidence for effects on population sizes to date. Therefore, we compared population trends of Dutch

  5. Agricultural Set-aside Programs and Grassland Birds: Insights from Broad-scale Population Trends

    Directory of Open Access Journals (Sweden)

    S. Riffell

    2008-10-01

    Full Text Available The Conservation Reserve Program (CRP is a voluntary set-aside program in the United States designed to amelioratesoil erosion, control crop overproduction, enhance water quality, and provide wildlife habitat by replacing crops with other forms of land cover. Because CRP includes primarily grass habitats, it has great potential to benefitdeclining North American grassland bird populations. We looked at the change in national and state population trends of grassland birds and related changes to cover-specific CRP variables (previous research grouped all CRP practices. Changes in national trends after the initiation of the CRP were inconclusive, but we observed signficant bird-CRP relations at the state level. Most bird-CRP relations were positive, except for some species associated with habitats that CRP replaced. Practice- and configuration-specific CRP variables were related to grassland bird trends, rather than a generic measure of all CRP types combined. Considering all CRP land as a single, distinct habitat type may obscure actual relations between birds and set-aside characteristics. Understanding and predictingthe effects of set-aside programs (like CRP or agri-environment schemes on grassland birds is complex and difficult. Because available broad-scale datasets are less than adequate, studies should be conducted at a variety of spatial and temporal scales.

  6. Declines in moth populations stress the need for conserving dark nights.

    Science.gov (United States)

    van Langevelde, Frank; Braamburg-Annegarn, Marijke; Huigens, Martinus E; Groendijk, Rob; Poitevin, Olivier; van Deijk, Jurriën R; Ellis, Willem N; van Grunsven, Roy H A; de Vos, Rob; Vos, Rutger A; Franzén, Markus; WallisDeVries, Michiel F

    2018-03-01

    Given the global continuous rise, artificial light at night is often considered a driving force behind moth population declines. Although negative effects on individuals have been shown, there is no evidence for effects on population sizes to date. Therefore, we compared population trends of Dutch macromoth fauna over the period 1985-2015 between moth species that differ in phototaxis and adult circadian rhythm. We found that moth species that show positive phototaxis or are nocturnally active have stronger negative population trends than species that are not attracted to light or are diurnal species. Our results indicate that artificial light at night is an important factor in explaining declines in moth populations in regions with high artificial night sky brightness. Our study supports efforts to reduce the impacts of artificial light at night by promoting lamps that do not attract insects and reduce overall levels of illumination in rural areas to reverse declines of moth populations. © 2017 John Wiley & Sons Ltd.

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

    Science.gov (United States)

    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.

  8. Foraging Habitat Quality Constrains Effectiveness of Artificial Nest-Site Provisioning in Reversing Population Declines in a Colonial Cavity Nester

    Science.gov (United States)

    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.

    Directory of Open Access Journals (Sweden)

    Inês Catry

    Full Text Available 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

  10. Trapped in the extinction vortex? Strong genetic effects in a declining vertebrate population

    Directory of Open Access Journals (Sweden)

    Larsson Mikael

    2010-02-01

    Full Text Available Abstract Background Inbreeding and loss of genetic diversity are expected to increase the extinction risk of small populations, but detailed tests in natural populations are scarce. We combine long-term population and fitness data with those from two types of molecular markers to examine the role of genetic effects in a declining metapopulation of southern dunlins Calidris alpina schinzii, an endangered shorebird. Results The decline is associated with increased pairings between related individuals, including close inbreeding (as revealed by both field observations of parentage and molecular markers. Furthermore, reduced genetic diversity seems to affect individual fitness at several life stages. Higher genetic similarity between mates correlates negatively with the pair's hatching success. Moreover, offspring produced by related parents are more homozygous and suffer from increased mortality during embryonic development and possibly also after hatching. Conclusions Our results demonstrate strong genetic effects in a rapidly declining population, emphasizing the importance of genetic factors for the persistence of small populations.

  11. Ocean-wide Drivers of Migration Strategies and Their Influence on Population Breeding Performance in a Declining Seabird.

    Science.gov (United States)

    Fayet, Annette L; Freeman, Robin; Anker-Nilssen, Tycho; Diamond, Antony; Erikstad, Kjell E; Fifield, Dave; Fitzsimmons, Michelle G; Hansen, Erpur S; Harris, Mike P; Jessopp, Mark; Kouwenberg, Amy-Lee; Kress, Steve; Mowat, Stephen; Perrins, Chris M; Petersen, Aevar; Petersen, Ib K; Reiertsen, Tone K; Robertson, Gregory J; Shannon, Paula; Sigurðsson, Ingvar A; Shoji, Akiko; Wanless, Sarah; Guilford, Tim

    2017-12-18

    Which factors shape animals' migration movements across large geographical scales, how different migratory strategies emerge between populations, and how these may affect population dynamics are central questions in the field of animal migration [1] that only large-scale studies of migration patterns across a species' range can answer [2]. To address these questions, we track the migration of 270 Atlantic puffins Fratercula arctica, a red-listed, declining seabird, across their entire breeding range. We investigate the role of demographic, geographical, and environmental variables in driving spatial and behavioral differences on an ocean-basin scale by measuring puffins' among-colony differences in migratory routes and day-to-day behavior (estimated with individual daily activity budgets and energy expenditure). We show that competition and local winter resource availability are important drivers of migratory movements, with birds from larger colonies or with poorer local winter conditions migrating further and visiting less-productive waters; this in turn led to differences in flight activity and energy expenditure. Other behavioral differences emerge with latitude, with foraging effort and energy expenditure increasing when birds winter further north in colder waters. Importantly, these ocean-wide migration patterns can ultimately be linked with breeding performance: colony productivity is negatively associated with wintering latitude, population size, and migration distance, which demonstrates the cost of competition and migration on future breeding and the link between non-breeding and breeding periods. Our results help us to understand the drivers of animal migration and have important implications for population dynamics and the conservation of migratory species. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    OpenAIRE

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

    2015-01-01

    At a regional scale, lion populations in West, Central, and East Africa are likely to suffer a projected 50% decline over the next two decades, whereas lion populations are only increasing in southern Africa. Many lion populations are either now gone or expected to disappear within the next few decades to the extent that the intensively managed populations in southern Africa may soon supersede the iconic savannah landscapes in East Africa as the most successful sites for lion conservation. Th...

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

    Science.gov (United States)

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

    2015-01-01

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

  14. Development of a practical modeling framework for estimating the impact of wind technology on bird populations

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, M.L. [California State Univ., Sacramento, CA (United States); Pollock, K.H. [North Carolina State Univ., Raleigh, NC (United States)

    1997-11-01

    One of the most pressing environmental concerns related to wind project development is the potential for avian fatalities caused by the turbines. The goal of this project is to develop a useful, practical modeling framework for evaluating potential wind power plant impacts that can be generalized to most bird species. This modeling framework could be used to get a preliminary understanding of the likelihood of significant impacts to birds, in a cost-effective way. The authors accomplish this by (1) reviewing the major factors that can influence the persistence of a wild population; (2) briefly reviewing various models that can aid in estimating population status and trend, including methods of evaluating model structure and performance; (3) reviewing survivorship and population projections; and (4) developing a framework for using models to evaluate the potential impacts of wind development on birds.

  15. Development of a practical modeling framework for estimating the impact of wind technology on bird populations

    International Nuclear Information System (INIS)

    Morrison, M.L.; Pollock, K.H.

    1997-11-01

    One of the most pressing environmental concerns related to wind project development is the potential for avian fatalities caused by the turbines. The goal of this project is to develop a useful, practical modeling framework for evaluating potential wind power plant impacts that can be generalized to most bird species. This modeling framework could be used to get a preliminary understanding of the likelihood of significant impacts to birds, in a cost-effective way. The authors accomplish this by (1) reviewing the major factors that can influence the persistence of a wild population; (2) briefly reviewing various models that can aid in estimating population status and trend, including methods of evaluating model structure and performance; (3) reviewing survivorship and population projections; and (4) developing a framework for using models to evaluate the potential impacts of wind development on birds

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

    Science.gov (United States)

    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. Glutathione S-transferase genotypes modify lung function decline in the general population: SAPALDIA cohort study

    Directory of Open Access Journals (Sweden)

    Ackermann-Liebrich Ursula

    2007-01-01

    Full Text Available Abstract Background Understanding the environmental and genetic risk factors of accelerated lung function decline in the general population is a first step in a prevention strategy against the worldwide increasing respiratory pathology of chronic obstructive pulmonary disease (COPD. Deficiency in antioxidative and detoxifying Glutathione S-transferase (GST gene has been associated with poorer lung function in children, smokers and patients with respiratory diseases. In the present study, we assessed whether low activity variants in GST genes are also associated with accelerated lung function decline in the general adult population. Methods We examined with multiple regression analysis the association of polymorphisms in GSTM1, GSTT1 and GSTP1 genes with annual decline in FEV1, FVC, and FEF25–75 during 11 years of follow-up in 4686 subjects of the prospective SAPALDIA cohort representative of the Swiss general population. Effect modification by smoking, gender, bronchial hyperresponisveness and age was studied. Results The associations of GST genotypes with FEV1, FVC, and FEF25–75 were comparable in direction, but most consistent for FEV1. GSTT1 homozygous gene deletion alone or in combination with GSTM1 homozygous gene deletion was associated with excess decline in FEV1 in men, but not women, irrespective of smoking status. The additional mean annual decline in FEV1 in men with GSTT1 and concurrent GSTM1 gene deletion was -8.3 ml/yr (95% confidence interval: -12.6 to -3.9 relative to men without these gene deletions. The GSTT1 effect on the FEV1 decline comparable to the observed difference in FEV1 decline between never and persistent smoking men. Effect modification by gender was statistically significant. Conclusion Our results suggest that genetic GSTT1 deficiency is a prevalent and strong determinant of accelerated lung function decline in the male general population.

  18. Results of the of wintering bird populations monitoring in the region of Nizhnee Prisurye

    Directory of Open Access Journals (Sweden)

    Ekaterina S. Preobrazhenskaya

    2016-05-01

    Full Text Available The monitoring of wintering bird populations in the region of Nizhnee Prisurie on the territory of Chuvash Republic was carried out in 1989–1990. From 2000 censuses were conducted on the territory of the nature reserve "Prisurskiy" and the National Park "Chavash Varmane". These regular censuses were called project "Parus" by the Menzbir Ornithological Society of the Russian Academy of Sciences. The last ten years they were also included in the overall-Russian campaign "Euro-Asian Christmas Bird Counts" project from the Russian Birds Conservation Union. During these 20 years there were 44 bird species registered in the studied area. Eleven of them are marked by single or rare. Four species - Regulus regulus, Aegithalos caudatus, Spinus spinus and Carduelis carduelis – increased their abundance from 1990 till the middle 2000-s and then – decreased. Dendrocopos minor showed the opposite trend. The abundance of 13 species in the 1990-s was higher, sometimes significantly, than in the 2000s and 2010s. The reason may be searched in the differences between the censuses areas in 1990s and 2000s. However, the decreasing of the population densities is typical for other forest species, not only in Nizhnee Prisurie, but also in other model territories. In general, during the last 25 years we can see negative trends in the population dynamics of wintering bird species within the East European plain.

  19. Identifying causes for population decline of the brown hare in agricultural landscapes in Denmark

    DEFF Research Database (Denmark)

    Jensen, Trine-Lee Wincentz

    In recent decades the brown hare (Lepus europaeus) population in Denmark has undergone a substantial decline, but proximate causes are unknown and little is known about actual densities. In this thesis, hare populations are investigated with respect to age composition and reproductive parameters...... population are caused by reduced juvenile recruitment. Point transect counts are suitable and corrections for detection necessary, when monitoring hare populations, but work is still needed, before the effects of e.g. road avoidance on density estimates are fully clarified....... proportions in game bags have dropped significantly since the 1950ies. Simple matrix population models with variable juvenile recruitment predict the similar population growth rates as actually observed in the annual bag records. The model substantiates the supposition that declines in the Danish hare...

  20. Urban decline within the region: Understanding the intra-regional differentiation in urban population development in the declining regions Saarland and Southern-Limburg

    NARCIS (Netherlands)

    Hoekveld, J.J.

    2014-01-01

    Urban decline, urban shrinkage and population decline are a few terms which describe the transformation processes currently going on in many cities and regions throughout the world. We are beginning to understand the driving forces of these urban transformation processes - such as structural

  1. The protozoan parasite Trichomonas gallinae causes adult and nestling mortality in a declining population of European Turtle Doves, Streptopelia turtur.

    Science.gov (United States)

    Stockdale, Jennifer E; Dunn, Jenny C; Goodman, Simon J; Morris, Antony J; Sheehan, Danaë K; Grice, Philip V; Hamer, Keith C

    2015-03-01

    Studies incorporating the ecology of clinical and sub-clinical disease in wild populations of conservation concern are rare. Here we examine sub-clinical infection by Trichomonas gallinae in a declining population of free-living European Turtle Doves and suggest caseous lesions cause mortality in adults and nestlings through subsequent starvation and/or suffocation. We found a 100% infection rate by T. gallinae in adult and nestling Turtle Doves (n = 25) and observed clinical signs in three adults and four nestlings (28%). Adults with clinical signs displayed no differences in any skeletal measures of size but had a mean 3.7% reduction in wing length, with no overlap compared to those without clinical signs. We also identified T. gallinae as the suggested cause of mortality in one Red-legged Partridge although disease presentation was different. A minimum of four strains of T. gallinae, characterized at the ITS/5.8S/ITS2 ribosomal region, were isolated from Turtle Doves. However, all birds with clinical signs (Turtle Doves and the Red-legged Partridge) carried a single strain of T. gallinae, suggesting that parasite spill over between Columbidae and Galliformes is a possibility that should be further investigated. Overall, we highlight the importance of monitoring populations for sub-clinical infection rather than just clinical disease.

  2. State-space modelling reveals proximate causes of harbour seal population declines.

    Science.gov (United States)

    Matthiopoulos, Jason; Cordes, Line; Mackey, Beth; Thompson, David; Duck, Callan; Smout, Sophie; Caillat, Marjolaine; Thompson, Paul

    2014-01-01

    Declines in large vertebrate populations are widespread but difficult to detect from monitoring data and hard to understand due to a multiplicity of plausible biological explanations. In parts of Scotland, harbour seals (Phoca vitulina) have been in decline for 10 years. To evaluate the contributions of different proximate causes (survival, fecundity, observation artefacts) to this decline, we collated behavioural, demographic and population data from one intensively studied population in part of the Moray Firth (north-east Scotland). To these, we fit a state-space model comprising age-structured dynamics and a detailed account of observation errors. After accounting for culling (estimated by our model as 14% of total mortality), the main driver of the historical population decline was a decreasing trend in survival of young individuals combined with (previously unrecognised) low levels of pupping success. In more recent years, the model provides evidence for considerable increases in breeding success and consistently high levels of adult survival. However, breeding success remains the most volatile demographic component of the population. Forecasts from the model indicate a slow population recovery, providing cautious support for recent management measures. Such investigations of the proximate causes of population change (survival, fecundity and observation errors) provide valuable short-term support for the management of population declines, helping to focus future data collection on those ultimate causal mechanisms that are not excluded by the demographic evidence. The contribution of specific ultimate drivers (e.g. shooting mortality or competitors) can also be quantified by including them as covariates to survival or fecundity.

  3. Diet composition of a declining steppe bird the Little Bustard (Tetrax tetrax in relation to farming practices

    Directory of Open Access Journals (Sweden)

    Carolina Bravo

    2017-06-01

    Full Text Available Foraging strategies and diet selection play an essential role in individual survival and reproductive success. The study of feeding ecology becomes crucial when it concerns endangered species such as the Little Bustard (Tetrax tetrax, whose populations are suffering strong declines as a consequence of agricultural intensification. Despite the fact that several populations are overwintering in areas affected by agricultural transformation, nothing is known about how feeding behavior responds to these changes. We studied for the first time the winter diet composition of the Little Bustard in Spain and compared it between areas with two different farming systems: dry and irrigated farmland. Diet was studied through the micro-histological analysis of 357 droppings collected in 16 locations across the wintering range of the Little Bustard in Spain. Up to 62 plant species were identified. Most consumed species were cultivated legumes (46.7% and dicotyledon weeds (45.6%, while monocotyledons were scarcely consumed (7.7%. Diet composition differed significantly between dry and irrigated farmland areas. In irrigated areas, diet was mainly composed of legumes, in particular alfalfa (Medicago sativa. In contrast, in dry farmland areas diet was more diverse, composed mainly of weeds (Compositae, Papaveraceae, and Cruciferae and also cultivated legumes, particularly vetch (Vicia sativa. These results suggest that legume crops could be an effective measure to improve habitat quality in areas with scarce food resources. However, in the case of irrigated areas, the strong reliance on alfalfa could make the Little Bustard more vulnerable to changes in land use. This study is the first step to understand the winter trophic requirements of the endangered Little Bustard, but further research is necessary to understand the food requirements of this species during the entire annual cycle.

  4. Seasonal associations with urban light pollution for nocturnally migrating bird populations.

    Science.gov (United States)

    La Sorte, Frank A; Fink, Daniel; Buler, Jeffrey J; Farnsworth, Andrew; Cabrera-Cruz, Sergio A

    2017-11-01

    The spatial extent and intensity of artificial light at night (ALAN) has increased worldwide through the growth of urban environments. There is evidence that nocturnally migrating birds are attracted to ALAN, and there is evidence that nocturnally migrating bird populations are more likely to occur in urban areas during migration, especially in the autumn. Here, we test if urban sources of ALAN are responsible, at least in part, for these observed urban associations. We use weekly estimates of diurnal occurrence and relative abundance for 40 nocturnally migrating bird species that breed in forested environments in North America to assess how associations with distance to urban areas and ALAN are defined across the annual cycle. Migratory bird populations presented stronger than expected associations with shorter distances to urban areas during migration, and stronger than expected association with higher levels of ALAN outside and especially within urban areas during migration. These patterns were more pronounced during autumn migration, especially within urban areas. Outside of the two migration periods, migratory bird populations presented stronger than expected associations with longer distances to urban areas, especially during the nonbreeding season, and weaker than expected associations with the highest levels of ALAN outside and especially within urban areas. These findings suggest that ALAN is associated with higher levels of diurnal abundance along the boundaries and within the interior of urban areas during migration, especially in the autumn when juveniles are undertaking their first migration journey. These findings support the conclusion that urban sources of ALAN can broadly effect migratory behavior, emphasizing the need to better understand the implications of ALAN for migratory bird populations. © 2017 John Wiley & Sons Ltd.

  5. Fitness decline under osmotic stress in Caenorhabditis elegans populations subjected to spontaneous mutation accumulation at varying population sizes.

    Science.gov (United States)

    Katju, Vaishali; Packard, Lucille B; Keightley, Peter D

    2018-04-01

    The consequences of mutations for population fitness depends on their individual selection coefficients and the effective population size. An earlier study of Caenorhabditis elegans spontaneous mutation accumulation lines evolved for 409 generations at three population sizes found that N e   = 1 populations declined significantly in fitness whereas the fitness of larger populations (N e   = 5, 50) was indistinguishable from the ancestral control under benign conditions. To test if larger MA populations harbor a load of cryptic deleterious mutations that are obscured under benign laboratory conditions, we measured fitness under osmotic stress via exposure to hypersaline conditions. The fitness of N e   = 1 lines exhibited a further decline under osmotic stress compared to benign conditions. However, the fitness of larger populations remained indistinguishable from that of the ancestral control. The average effects of deleterious mutations in N e   = 1 lines were estimated to be 22% for productivity and 14% for survivorship, exceeding values previously detected under benign conditions. Our results suggest that fitness decline is due to large effect mutations that are rapidly removed via selection even in small populations, with implications for conservation practices. Genetic stochasticity may not be as potent and immediate a threat to the persistence of small populations as other demographic and environmental stochastic factors. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

  6. Population trends for North American winter birds based on hierarchical models

    Science.gov (United States)

    Soykan, Candan U.; Sauer, John; Schuetz, Justin G.; LeBaron, Geoffrey S.; Dale, Kathy; Langham, Gary M.

    2016-01-01

    Managing widespread and persistent threats to birds requires knowledge of population dynamics at large spatial and temporal scales. For over 100 yrs, the Audubon Christmas Bird Count (CBC) has enlisted volunteers in bird monitoring efforts that span the Americas, especially southern Canada and the United States. We employed a Bayesian hierarchical model to control for variation in survey effort among CBC circles and, using CBC data from 1966 to 2013, generated early-winter population trend estimates for 551 species of birds. Selecting a subset of species that do not frequent bird feeders and have ≥25% range overlap with the distribution of CBC circles (228 species) we further estimated aggregate (i.e., across species) trends for the entire study region and at the level of states/provinces, Bird Conservation Regions, and Landscape Conservation Cooperatives. Moreover, we examined the relationship between ten biological traits—range size, population size, migratory strategy, habitat affiliation, body size, diet, number of eggs per clutch, age at sexual maturity, lifespan, and tolerance of urban/suburban settings—and CBC trend estimates. Our results indicate that 68% of the 551 species had increasing trends within the study area over the interval 1966–2013. When trends were examined across the subset of 228 species, the median population trend for the group was 0.9% per year at the continental level. At the regional level, aggregate trends were positive in all but a few areas. Negative population trends were evident in lower latitudes, whereas the largest increases were at higher latitudes, a pattern consistent with range shifts due to climate change. Nine of 10 biological traits were significantly associated with median population trend; however, none of the traits explained >34% of the deviance in the data, reflecting the indirect relationships between population trend estimates and species traits. Trend estimates based on the CBC are broadly congruent with

  7. Effects of uncertainty and variability on population declines and IUCN Red List classifications.

    Science.gov (United States)

    Rueda-Cediel, Pamela; Anderson, Kurt E; Regan, Tracey J; Regan, Helen M

    2018-01-22

    The International Union for Conservation of Nature (IUCN) Red List Categories and Criteria is a quantitative framework for classifying species according to extinction risk. Population models may be used to estimate extinction risk or population declines. Uncertainty and variability arise in threat classifications through measurement and process error in empirical data and uncertainty in the models used to estimate extinction risk and population declines. Furthermore, species traits are known to affect extinction risk. We investigated the effects of measurement and process error, model type, population growth rate, and age at first reproduction on the reliability of risk classifications based on projected population declines on IUCN Red List classifications. We used an age-structured population model to simulate true population trajectories with different growth rates, reproductive ages and levels of variation, and subjected them to measurement error. We evaluated the ability of scalar and matrix models parameterized with these simulated time series to accurately capture the IUCN Red List classification generated with true population declines. Under all levels of measurement error tested and low process error, classifications were reasonably accurate; scalar and matrix models yielded roughly the same rate of misclassifications, but the distribution of errors differed; matrix models led to greater overestimation of extinction risk than underestimations; process error tended to contribute to misclassifications to a greater extent than measurement error; and more misclassifications occurred for fast, rather than slow, life histories. These results indicate that classifications of highly threatened taxa (i.e., taxa with low growth rates) under criterion A are more likely to be reliable than for less threatened taxa when assessed with population models. Greater scrutiny needs to be placed on data used to parameterize population models for species with high growth rates

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

    Science.gov (United States)

    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.

  9. 5 Is the Bird Population in the Hadejia-Nguru.cdr

    African Journals Online (AJOL)

    user

    resources due to increasing human populations, has led to reclamation of vast wetland areas and loss of ..... Little Green Bee-eaterMerops orientalis. –. –. 5.0. 0.08. Motacillidae Yellow WagtailMotacilla flava. 289.0 .... diversion of water and use of nets for fishing, could have severely affected waterbirds and fish-eating birds.

  10. Frequency of migrants and migratory activity are genetically correlated in a bird population: Evolutionary implications

    NARCIS (Netherlands)

    Pulido, F.; Berthold, P.; Van Noordwijk, A.J.

    1996-01-01

    Most migratory bird populations are composed of individuals that migrate and individuals that remain resident, While the role of ecological factors in maintaining this behavioral dimorphism has received much attention, the importance of genetic constraints on the evolution of avian migration has not

  11. Population growth in a wild bird is buffered against phenological mismatch

    NARCIS (Netherlands)

    Reed, T.; Grotan, V.; Jenouvrier, S.; Saether, B.E.; Visser, M.E.

    2013-01-01

    road-scale environmental changes are altering patterns of natural selection in the wild, but few empirical studies have quantified the demographic cost of sustained directional selection in response to these changes. We tested whether population growth in a wild bird is negatively affected by

  12. A multispecies test of source-sink indicators to prioritize habitat for declining populations.

    Science.gov (United States)

    Heinrichs, Julie A; Lawler, Joshua J; Schumaker, Nathan H; Wilsey, Chad B; Monroe, Kira C; Aldridge, Cameron L

    2017-11-29

    For species at risk of decline or extinction in source-sink systems, sources are an obvious target for habitat protection actions. However, the way in which source habitats are identified and prioritized can reduce the effectiveness of conservation actions. Although sources and sinks are conceptually defined using both demographic and movement criteria, simplifications are often required in systems with limited data. To assess the conservation outcomes of alternative source metrics and resulting prioritizations, we simulated population dynamics and extinction risk for 3 endangered species. Using empirically based habitat population models, we linked habitat maps with measured site- or habitat-specific demographic conditions, movement abilities, and behaviors. We calculated source-sink metrics over a range of periods of data collection and prioritized consistently high-output sources for conservation. We then tested whether prioritized patches identified the habitats that most affected persistence by removing them and measuring the population response. Conservation decisions based on different source-sink metrics and durations of data collection affected species persistence. Shorter time series obscured the ability of metrics to identify influential habitats, particularly in temporally variable and slowly declining populations. Data-rich source-sink metrics that included both demography and movement information did not always identify the habitats with the greatest influence on extinction risk. In some declining populations, patch abundance better predicted influential habitats for short-term regional persistence. Because source-sink metrics (i.e., births minus deaths; births and immigrations minus deaths and emigration) describe net population conditions and cancel out gross population counts, they may not adequately identify influential habitats in declining populations. For many nonequilibrium populations, new metrics that maintain the counts of individual births

  13. The effects of organic inputs to estuaries on overwintering bird populations and communities

    International Nuclear Information System (INIS)

    Green, P.T.; Hill, D.A.; Clark, N.A.

    1992-01-01

    This study investigates the relationship between changes in organic inputs to river estuaries and other coastal intertidal areas, and changes in the populations of waterfowl in these habitats. This is done in the context of tidal barrage construction, where barrage construction and operation may coincide with the cleaning of estuarine water. A thorough review of the literature is undertaken to determine the current status of knowledge of bird/organic-enrichment interactions. The use of multivariate statistics for identifying gradients in similarity between bird communities (specifically waders) of different estuaries, irrespective of geographic locations is investigated. (UK)

  14. An Indicator of the Impact of Climatic Change on European Bird Populations

    Science.gov (United States)

    Gregory, Richard D.; Willis, Stephen G.; Jiguet, Frédéric; Voříšek, Petr; Klvaňová, Alena; van Strien, Arco; Huntley, Brian; Collingham, Yvonne C.; Couvet, Denis; Green, Rhys E.

    2009-01-01

    Rapid climatic change poses a threat to global biodiversity. There is extensive evidence that recent climatic change has affected animal and plant populations, but no indicators exist that summarise impacts over many species and large areas. We use data on long-term population trends of European birds to develop such an indicator. We find a significant relationship between interspecific variation in population trend and the change in potential range extent between the late 20th and late 21st centuries, forecasted by climatic envelope models. Our indicator measures divergence in population trend between bird species predicted by climatic envelope models to be favourably affected by climatic change and those adversely affected. The indicator shows a rapid increase in the past twenty years, coinciding with a period of rapid warming. PMID:19259270

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

    Science.gov (United States)

    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.

  16. Poison blamed for decline of Spain's majestic Black Vultures

    African Journals Online (AJOL)

    2007-03-01

    catastrophic” decline in numbers because of illegal poisoning by hunters. The use of poisoned bait to kill foxes, badgers, wild dogs, feral cats and smaller birds of prey has reduced the population by almost a half in the past decade,.

  17. Personality and basal metabolic rate in a wild bird population

    NARCIS (Netherlands)

    Bouwhuis, Sandra; Quinn, John L.; Sheldon, Ben C.; Verhulst, Simon

    Personality and metabolic rate are predicted to show covariance on methodological and functional grounds, but empirical studies at the individual level are rare, especially in natural populations. Here we assess the relationship between exploration behaviour, an important axis of personality, and

  18. Population decline of the little owl (Athene noctua scop.) in the Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Šálek, Martin; Schröpfer, L.

    2008-01-01

    Roč. 56, č. 3 (2008), s. 527-534 ISSN 1505-2249 Institutional research plan: CEZ:AV0Z60870520 Keywords : Little Owl * Athene noctua * population decline Subject RIV: EH - Ecology, Behaviour Impact factor: 0.443, year: 2008

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

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    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...

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

    OpenAIRE

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

    2017-01-01

    The strong focus on species extinctions, a critical aspect of the contemporary pulse of biological extinction, leads to a common misimpression that Earth’s biota is not immediately threatened, just slowly entering an episode of major biodiversity loss. This view overlooks the current trends of population declines and extinctions. Using a sample of 27,600 terrestrial vertebrate species, and a more detailed analysis of 177 mammal species, we show the extremely high degree of population decay in...

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

    Science.gov (United States)

    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.

  3. Endemic chronic wasting disease causes mule deer population decline in Wyoming.

    Directory of Open Access Journals (Sweden)

    Melia T DeVivo

    Full Text Available Chronic wasting disease (CWD is a fatal transmissible spongiform encephalopathy affecting white-tailed deer (Odocoileus virginianus, mule deer (Odocoileus hemionus, Rocky Mountain elk (Cervus elaphus nelsoni, and moose (Alces alces shirasi in North America. In southeastern Wyoming average annual CWD prevalence in mule deer exceeds 20% and appears to contribute to regional population declines. We determined the effect of CWD on mule deer demography using age-specific, female-only, CWD transition matrix models to estimate the population growth rate (λ. Mule deer were captured from 2010-2014 in southern Converse County Wyoming, USA. Captured adult (≥ 1.5 years old deer were tested ante-mortem for CWD using tonsil biopsies and monitored using radio telemetry. Mean annual survival rates of CWD-negative and CWD-positive deer were 0.76 and 0.32, respectively. Pregnancy and fawn recruitment were not observed to be influenced by CWD. We estimated λ = 0.79, indicating an annual population decline of 21% under current CWD prevalence levels. A model derived from the demography of only CWD-negative individuals yielded; λ = 1.00, indicating a stable population if CWD were absent. These findings support CWD as a significant contributor to mule deer population decline. Chronic wasting disease is difficult or impossible to eradicate with current tools, given significant environmental contamination, and at present our best recommendation for control of this disease is to minimize spread to new areas and naïve cervid populations.

  4. Population decline in the Delta caribou herd with reference to other Alaskan herds

    Directory of Open Access Journals (Sweden)

    Patrick Valkenburg et al.

    1996-01-01

    Full Text Available After growing continuously for nearly 15 years, the Delta caribou herd began to decline in 1989. Most other Interior Alaskan herds also began declining. In the Delta herd, and in other herds, the declines were caused primarily by high summer mortality of calves and increased natural mortality of adult females. Other minor causes included increased winter mortality of calves, and reduced parturition rates of 3-year-old and older females. The decline in the Delta herd also coincided with increased wolf (Canis lupus numbers, winters with deeper than normal snow, and warm summers. Mean body weight of annual samples of 10-month-old female calves was consistently low during the decline. Except in some of the smallest Interior Alaskan herds, we conclude that evidence for population regulation in Alaskan caribou is weak, and that herds are likely to fluctuate within a wide range of densities due to complex interactions of predation and weather. Unless wolf numbers are influenced by man, the size of a caribou herd in a given year is likely to be largely a function of its size during the previous population low and the number of years of favorable weather in the interim.

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

    Science.gov (United States)

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

    2017-07-25

    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.

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

    Science.gov (United States)

    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.

  7. Challenge infection as a means of determining the rate of disease resistant Trichomonas gallinae-free birds in a population.

    Science.gov (United States)

    Kocan, R M; Knisley, J O

    1970-01-01

    Trichomonas gallinae-free pigeons and mourning doves were infected with the Jones' Barn strain of T. gallinae to determine the rate of disease resistant T. gallinae-free birds in each population. Although all birds became infected 88% of the pigeons were resistant to trichomoniasis while 82% of the mourning doves were resistant. It was concluded that these birds had been previously infected and spontaneously lost their trichomonad fauna while retaining their resistance to fatal infection.

  8. The early bird gets the shrimp: Confronting assumptions of isotopic equilibrium and homogeneity in a wild bird population

    Science.gov (United States)

    Wunder, Michael B.; Jehl, Joseph R.; Stricker, Craig A.

    2012-01-01

    1. Because stable isotope distributions in organic material vary systematically across energy gradients that exist in ecosystems, community and population structures, and in individual physiological systems, isotope values in animal tissues have helped address a broad range of questions in animal ecology. It follows that every tissue sample provides an isotopic profile that can be used to study dietary or movement histories of individual animals. Interpretations of these profiles depend on the assumption that metabolic pools are isotopically well mixed and in equilibrium with dietary resources prior to tissue synthesis, and they extend to the population level by assuming isotope profiles are identically distributed for animals using the same proximal dietary resource. As these assumptions are never fully met, studying structure in the variance of tissue isotope values from wild populations is informative. 2. We studied variation in δ13C, δ15N, δ2H and δ18O data for feathers from a population of eared grebes (Podiceps nigricollis) that migrate to Great Salt Lake each fall to moult feathers. During this time, they cannot fly and feed almost exclusively on superabundant brine shrimp (Artemia franciscana). The ecological simplicity of this situation minimized the usual spatial and trophic complexities often present in natural studies of feather isotope values. 3. Ranges and variances of isotope values for the feathers were larger than those from previously published studies that report feather isotopic variance, but they were bimodally distributed in all isotope dimensions. Isotope values for proximal dietary resources and local surface water show that some of the feathers we assumed to have been grown locally must have been grown before birds reached isotopic equilibrium with local diet or immediately prior to arrival at Great Salt Lake. 4. Our study provides novel insights about resource use strategies in eared grebes during migration. More generally, it

  9. High urban population density of birds reflects their timing of urbanization.

    Science.gov (United States)

    Møller, Anders Pape; Diaz, Mario; Flensted-Jensen, Einar; Grim, Tomas; Ibáñez-Álamo, Juan Diego; Jokimäki, Jukka; Mänd, Raivo; Markó, Gábor; Tryjanowski, Piotr

    2012-11-01

    Living organisms generally occur at the highest population density in the most suitable habitat. Therefore, invasion of and adaptation to novel habitats imply a gradual increase in population density, from that at or below what was found in the ancestral habitat to a density that may reach higher levels in the novel habitat following adaptation to that habitat. We tested this prediction of invasion biology by analyzing data on population density of breeding birds in their ancestral rural habitats and in matched nearby urban habitats that have been colonized recently across a continental latitudinal gradient. We estimated population density in the two types of habitats using extensive point census bird counts, and we obtained information on the year of urbanization when population density in urban habitats reached levels higher than that of the ancestral rural habitat from published records and estimates by experienced ornithologists. Both the difference in population density between urban and rural habitats and the year of urbanization were significantly repeatable when analyzing multiple populations of the same species across Europe. Population density was on average 30 % higher in urban than in rural habitats, although density reached as much as 100-fold higher in urban habitats in some species. Invasive urban bird species that colonized urban environments over a long period achieved the largest increases in population density compared to their ancestral rural habitats. This was independent of whether species were anciently or recently urbanized, providing a unique cross-validation of timing of urban invasions. These results suggest that successful invasion of urban habitats was associated with gradual adaptation to these habitats as shown by a significant increase in population density in urban habitats over time.

  10. Invasion of Ligustrum lucidum (Oleaceae) in the southern Yungas: Changes in habitat properties and decline in bird diversity

    Science.gov (United States)

    Ayup, M. M.; Montti, L.; Aragón, R.; Grau, H. R.

    2014-01-01

    Ligustrum lucidum is the major exotic tree in NW Argentina montane forests (Yungas). To assess the effects of its expanding invasion on avian communities we (1) measured different habitat properties (vertical forest structure and composition, vegetation cover, light availability, air temperature, air relative humidity and soil litter depth), (2) compared bird species composition and diversity in Ligustrum-dominated and native-dominated secondary forests and (3) analyzed seasonal patterns and changes in these variables between forest types. The study was conducted during 2010-2011 wet and dry seasons, at two altitudinal zones: 500-800 and 1100-1450 masl. Compared with native forests, Ligustrum dominated forests had a more homogeneous vertical forest structure and denser canopy cover (resulting in lower understory solar radiation), significantly lower understory cover and lower litter depth. Air temperature and relative humidity did not differ between forests in either season. Solar radiation was higher in the dry season in both forest types, but litter depth showed opposite patterns between seasons depending on forest type. We recorded 59 bird species in 21 families. Bird species abundance, richness and diversity indexes were significantly lower in Ligustrum-dominated relative to native forests of similar successional age, which had almost twice as many species as the former. Avian communities differed between altitudinal zones, but the difference was stronger between Ligustrum and native-dominated forests. Avian community composition was less variable in time and space in native forests than in Ligustrum-dominated ones. Our results suggest that L. lucidum invasion generates structurally homogeneous and simpler forests that represent a less suitable habitat for a diverse avifauna. This illustrates the wide ecological changes (from habitat properties and ecosystem functioning to vertebrate community composition) that the subtropical mountain forests of Argentina are

  11. Artificial wetlands to augment use by estuarine birds

    Science.gov (United States)

    Zedler, Joy B.; Kus, Barbara E.

    1996-01-01

    The value of natural wetlands to bird populations is well-recognized, and declines in waterfowl numbers are often attributed to losses in wetland area. if the destruction of wetland reduces bird populations, then adding wetland habitats might improve the situation. This idea was tested in Tijuana Estuary in the late 1980s.

  12. Exposure of harbour seals Phoca vitulina to Brucella in declining populations across Scotland.

    Science.gov (United States)

    Kershaw, Joanna L; Stubberfield, Emma J; Foster, Geoffrey; Brownlow, Andrew; Hall, Ailsa J; Perrett, Lorraine L

    2017-09-20

    Since 2000 there has been a major decline in the abundance of Scottish harbour seals Phoca vitulina. The causes of the decline remain uncertain. The aim of this study was to establish the extent to which the seals in the regions of greatest decline have been exposed to Brucella, a bacterial pathogen that causes reproductive failure in terrestrial mammalian hosts. Tissues from dead seals collected between 1992 and 2013 were cultured for Brucella (n = 150). Serum samples collected from live capture-released seals (n = 343) between 1997 and 2012 were tested for Brucella antibodies using the Rose Bengal plate agglutination test (RBT) and a competitive enzyme-linked immunosorbent assay (cELISA). In total, 16% of seals cultured had Brucella isolated from one or more tissues, but there were no pathological signs of infection. The cELISA results were more sensitive than the RBT results, showing that overall 25.4% of seals were seropositive, with the highest seroprevalence in juveniles. As there was no evidence of either a higher seroprevalence or higher circulating antibody levels in seropositive animals in the areas with the greatest declines, it was concluded that Brucella infection is likely not a major contributing factor to recent declines. However, the consistently high proportion of seals exposed to Brucella indicates possible endemicity in these populations, likely due to B. pinnipedialis, which has demonstrated a preference for pinniped hosts. Importantly, given the close proximity between seals, humans and livestock in many areas, there is the potential for cross-species infections.

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

    Science.gov (United States)

    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

  14. The dynamics of fauna and population of birds in agricultural landscapes on the border of Kazan International Airport

    Science.gov (United States)

    Bespalov, A. F.; Belyaev, A. N.

    2018-01-01

    The dynamics of fauna and population of birds from agricultural lands near Kazan International Airport has been studied for one year. A total of 60 bird species have been registered, of which 26 species must be considered as highly dangerous to flying aircraft. With regard to seasonal activity, the nesting period (April - June) is the most hazardous, since it is characterized by maximum species richness and total population density of birds, as well as their high species diversity. Furthermore, a serious danger is posed by the period of postnesting nomadic movements and the onset of migrations (July - September) when the species diversity turns out to be the highest and the total population density begins to decrease. It has been recommended based on the obtained results that the current crops should be replaced by cultivars that will be less attractive to birds. In spring and autumn, certain bird hazing and frightening measures must be taken on a more regular basis.

  15. Influence of hiking trails on montane birds

    Science.gov (United States)

    William V. Deluca; David I. King

    2014-01-01

    Montane forests contribute significantly to regional biodiversity. Long-term monitoring data, often located along hiking trails, suggests that several indicator species of this ecosystem have declined in recent decades. Declining montane bird populations have been attributed to anthropogenic stressors such as climate change and atmospheric deposition. Several studies...

  16. Surveys of forest bird populations found in the vicinity of proposed geothermal project subzones in the district of Puna, Hawaii

    Energy Technology Data Exchange (ETDEWEB)

    Jacobi, J.D.; Reynolds, M.; Ritchotte, G.; Nielsen, B.; Viggiano, A.; Dwyer, J.

    1994-10-01

    This report presents data on the distribution and status of forest bird species found within the vicinity of proposed geothermal resource development on the Island of Hawaii. Potential impacts of the proposed development on the native bird populations found in the project are are addressed.

  17. Surveys of forest bird populations found in the vicinity of proposed geothermal project subzones in the district of Puna, Hawaii

    International Nuclear Information System (INIS)

    Jacobi, J.D.; Reynolds, M.; Ritchotte, G.; Nielsen, B.; Viggiano, A.; Dwyer, J.

    1994-10-01

    This report presents data on the distribution and status of forest bird species found within the vicinity of proposed geothermal resource development on the Island of Hawaii. Potential impacts of the proposed development on the native bird populations found in the project are are addressed

  18. Population Decline in Polish and Czech Cities during Post-socialism? Looking Behind the Official Statistics

    Czech Academy of Sciences Publication Activity Database

    Steinführer, A.; Bierzynski, A.; Grossmann, K.; Haase, A.; Kabisch, S.; Klusáček, Petr

    2010-01-01

    Roč. 47, č. 11 (2010), s. 2325-2346 ISSN 0042-0980 R&D Projects: GA AV ČR IAA300860903 Institutional research plan: CEZ:AV0Z30860518 Keywords : urban shrinkage * population decline * inner city Subject RIV: AO - Sociology, Demography Impact factor: 1.513, year: 2010 http://usj.sagepub.com/content/47/11/2325.full.pdf+html

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

    Science.gov (United States)

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

    2010-12-07

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

  20. Endemic chronic wasting disease causes mule deer population decline in Wyoming

    Science.gov (United States)

    DeVivo, Melia T.; Edmunds, David R.; Kauffman, Matthew J.; Schumaker, Brant A.; Binfet, Justin; Kreeger, Terry J.; Richards, Bryan J.; Schatzl, Hermann M.; Cornish, Todd

    2017-01-01

    Chronic wasting disease (CWD) is a fatal transmissible spongiform encephalopathy affecting white-tailed deer (Odocoileus virginianus), mule deer (Odocoileus hemionus), Rocky Mountain elk (Cervus elaphus nelsoni), and moose (Alces alces shirasi) in North America. In southeastern Wyoming average annual CWD prevalence in mule deer exceeds 20% and appears to contribute to regional population declines. We determined the effect of CWD on mule deer demography using age-specific, female-only, CWD transition matrix models to estimate the population growth rate (λ). Mule deer were captured from 2010–2014 in southern Converse County Wyoming, USA. Captured adult (≥ 1.5 years old) deer were tested ante-mortem for CWD using tonsil biopsies and monitored using radio telemetry. Mean annual survival rates of CWD-negative and CWD-positive deer were 0.76 and 0.32, respectively. Pregnancy and fawn recruitment were not observed to be influenced by CWD. We estimated λ= 0.79, indicating an annual population decline of 21% under current CWD prevalence levels. A model derived from the demography of only CWD-negative individuals yielded; λ = 1.00, indicating a stable population if CWD were absent. These findings support CWD as a significant contributor to mule deer population decline. Chronic wasting disease is difficult or impossible to eradicate with current tools, given significant environmental contamination, and at present our best recommendation for control of this disease is to minimize spread to new areas and naïve cervid populations.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  3. Population trends of central European montane birds provide evidence for adverse impacts of climate change on high-altitude species

    Czech Academy of Sciences Publication Activity Database

    Flousek, J.; Telenský, Tomáš; Hanzelka, J.; Reif, J.

    2015-01-01

    Roč. 10, č. 10 (2015), č. článku e0139465. E-ISSN 1932-6203 Institutional support: RVO:68081766 Keywords : Elevational range shifts * Life-history traits * Arrival date * Boreal birds * Habitat loss * Biodiversity * Declines Subject RIV: EH - Ecology, Behaviour Impact factor: 3.057, year: 2015

  4. Identifying causes for population decline of the brown hare in agricultural landscapes in Denmark

    DEFF Research Database (Denmark)

    Jensen, Trine-Lee Wincentz

    in relation to habitat and phenotype, and point transect counts are evaluated in assessing hare densities. High spatial variation in post-natal survival of offspring is observed. Some variation in the demographic and phenotypic (size, weight) parameters is attributable to habitat composition. The juvenile...... proportions in game bags have dropped significantly since the 1950ies. Simple matrix population models with variable juvenile recruitment predict the similar population growth rates as actually observed in the annual bag records. The model substantiates the supposition that declines in the Danish hare...... population are caused by reduced juvenile recruitment. Point transect counts are suitable and corrections for detection necessary, when monitoring hare populations, but work is still needed, before the effects of e.g. road avoidance on density estimates are fully clarified....

  5. Predicting impacts of future human population growth and development on occupancy rates of forest-dependent birds

    Science.gov (United States)

    Brown, Michelle L.; Donovan, Therese; Schwenk, W. Scott; Theobald, David M.

    2014-01-01

    Forest loss and fragmentation are among the largest threats to forest-dwelling wildlife species today, and projected increases in human population growth are expected to increase these threats in the next century. We combined spatially-explicit growth models with wildlife distribution models to predict the effects of human development on 5 forest-dependent bird species in Vermont, New Hampshire, and Massachusetts, USA. We used single-species occupancy models to derive the probability of occupancy for each species across the study area in the years 2000 and 2050. Over half a million new housing units were predicted to be added to the landscape. The maximum change in housing density was nearly 30 houses per hectare; however, 30% of the towns in the study area were projected to add less than 1 housing unit per hectare. In the face of predicted human growth, the overall occupancy of each species decreased by as much as 38% (ranging from 19% to 38% declines in the worst-case scenario) in the year 2050. These declines were greater outside of protected areas than within protected lands. Ninety-seven percent of towns experienced some decline in species occupancy within their borders, highlighting the value of spatially-explicit models. The mean decrease in occupancy probability within towns ranged from 3% for hairy woodpecker to 8% for ovenbird and hermit thrush. Reductions in occupancy probability occurred on the perimeters of cities and towns where exurban development is predicted to increase in the study area. This spatial approach to wildlife planning provides data to evaluate trade-offs between development scenarios and forest-dependent wildlife species.

  6. New approaches to the analysis of population trends in land birds: Comment

    Science.gov (United States)

    Link, W.A.; Sauer, J.R.

    1997-01-01

    James et al. (1996, Ecology 77:13-27) used data from the North American Breeding Bird Survey (BBS) to examine geographic variability in patterns of population change for 26 species of wood warblers. They emphasized the importance of evaluating nonlinear patterns of change in bird populations, proposed LOESS-based non-parametric and semi-parametric analyses of BBS data, and contrasted their results with other analyses, including those of Robbins et al. (1989, Proceedings of the National Academy of Sciences 86: 7658-7662) and Peterjohn et al. (1995, Pages 3-39 in T. E. Martin and D. M. Finch, eds. Ecology and management of Neotropical migratory birds: a synthesis and review of critical issues. Oxford University Press, New York.). In this note, we briefly comment on some of the issues that arose from their analysis of BBS data, suggest a few aspects of the survey that should inspire caution in analysts, and review the differences between the LOESS-based procedures and other procedures (e.g., Link and Sauer 1994). We strongly discourage the use of James et al.'s completely non-parametric procedure, which fails to account for observer effects. Our comparisons of estimators adds to the evidence already present in the literature of the bias associated with omitting observer information in analyses of BBS data. Bias resulting from change in observer abilities should be a consideration in any analysis of BBS data.

  7. Long-term effects of different forest regeneration methods on mature forest birds

    Science.gov (United States)

    Roger W. Perry; Julianna M.A. Jenkins; Ronald E. Thill; Frank R. Thompson

    2018-01-01

    Changes in forest structure that result from silviculture, including timber harvest, can positively or negatively affect bird species that use forests. Because many bird species associated with mature forests are facing population declines, managers need to know how timber harvesting affects species of birds that rely on mature trees or forests for breeding, foraging,...

  8. The demographic drivers of local population dynamics in two rare migratory birds.

    Science.gov (United States)

    Schaub, Michael; Reichlin, Thomas S; Abadi, Fitsum; Kéry, Marc; Jenni, Lukas; Arlettaz, Raphaël

    2012-01-01

    The exchange of individuals among populations can have strong effects on the dynamics and persistence of a given population. Yet, estimation of immigration rates remains one of the greatest challenges for animal demographers. Little empirical knowledge exists about the effects of immigration on population dynamics. New integrated population models fitted using Bayesian methods enable simultaneous estimation of fecundity, survival and immigration, as well as the growth rate of a population of interest. We applied this novel analytical framework to the demography of two populations of long-distance migratory birds, hoopoe Upupa epops and wryneck Jynx torquilla, in a study area in south-western Switzerland. During 2002-2010, the hoopoe population increased annually by 11%, while the wryneck population remained fairly stable. Apparent juvenile and adult survival probability was nearly identical in both species, but fecundity and immigration were slightly higher in the hoopoe. Hoopoe population growth rate was strongly correlated with juvenile survival, fecundity and immigration, while that of wrynecks strongly correlated only with immigration. This indicates that demographic components impacting the arrival of new individuals into the populations were more important for their dynamics than demographic components affecting the loss of individuals. The finding that immigration plays a crucial role in the population growth rates of these two rare species emphasizes the need for a broad rather than local perspective for population studies, and the development of wide-scale conservation actions.

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

    Science.gov (United States)

    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.

  10. First evidence and predictions of Plasmodium transmission in Alaskan bird populations.

    Directory of Open Access Journals (Sweden)

    Claire Loiseau

    Full Text Available The unprecedented rate of change in the Arctic climate is expected to have major impacts on the emergence of infectious diseases and host susceptibility to these diseases. It is predicted that malaria parasites will spread to both higher altitudes and latitudes with global warming. Here we show for the first time that avian Plasmodium transmission occurs in the North American Arctic. Over a latitudinal gradient in Alaska, from 61°N to 67°N, we collected blood samples of resident and migratory bird species. We found both residents and hatch year birds infected with Plasmodium as far north as 64°N, providing clear evidence that malaria transmission occurs in these climates. Based on our empirical data, we make the first projections of the habitat suitability for Plasmodium under a future-warming scenario in Alaska. These findings raise new concerns about the spread of malaria to naïve host populations.

  11. Fat mass gain predicts estimated GFR decline in a relatively healthy Korean population.

    Science.gov (United States)

    Hyun, Young Youl; Kim, Hyang; Lee, Kyu Beck

    2014-01-01

    Previous studies have shown that obesity is a risk factor for estimated glomerular filtration rate (eGFR) decline and chronic kidney disease (CKD). However, the relationship between fat mass directly measured by bioimpedance analysis and eGFR is not well known. We analyzed 21,859 participants without CKD at baseline who underwent two health checkups at a 5-year interval during 2002-2009. Fat mass was measured by Inbody 3.0 (Biospace, Seoul, Korea). eGFR decline was defined as eGFR 1.2 kg). After 5 years, 246 cases of eGFR decline were observed. Multivariate logistic analysis revealed that age (OR 1.03, 95% CI 1.02-1.05, p < 0.001), diabetes mellitus (OR 2.04, 95% CI 1.22-3.40, p = 0.007), baseline eGFR (OR 0.80, 95% CI 0.78-0.83, p < 0.001) and higher tertile of fat mass change (OR 1.58, 95% CI 1.16-2.13, p = 0.003) were associated with eGFR decline after adjustment for sex, hypertension, dyslipidemia, cardiovascular disease, smoking status, body mass index, and high-density lipoprotein cholesterol level. Fat mass gain over 5 years was independently associated with eGFR decline to <60 ml/min/1.73 m(2) in a relatively healthy Korean population. This finding suggests that lifestyle changes to prevent fat mass gain could be protective against the development of CKD. © 2014 S. Karger AG, Basel.

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

    Science.gov (United States)

    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.

  13. No Association between Personality and Candidate Gene Polymorphisms in a Wild Bird Population.

    Directory of Open Access Journals (Sweden)

    Hannah A Edwards

    Full Text Available Consistency of between-individual differences in behaviour or personality is a phenomenon in populations that can have ecological consequences and evolutionary potential. One way that behaviour can evolve is to have a genetic basis. Identifying the molecular genetic basis of personality could therefore provide insight into how and why such variation is maintained, particularly in natural populations. Previously identified candidate genes for personality in birds include the dopamine receptor D4 (DRD4, and serotonin transporter (SERT. Studies of wild bird populations have shown that exploratory and bold behaviours are associated with polymorphisms in both DRD4 and SERT. Here we tested for polymorphisms in DRD4 and SERT in the Seychelles warbler (Acrocephalus sechellensis population on Cousin Island, Seychelles, and then investigated correlations between personality and polymorphisms in these genes. We found no genetic variation in DRD4, but identified four polymorphisms in SERT that clustered into five haplotypes. There was no correlation between bold or exploratory behaviours and SERT polymorphisms/haplotypes. The null result was not due to lack of power, and indicates that there was no association between these behaviours and variation in the candidate genes tested in this population. These null findings provide important data to facilitate representative future meta-analyses on candidate personality genes.

  14. Migratory bird hunter opinions regarding potential management strategies for controlling light goose populations

    Science.gov (United States)

    Dinges, Andrew J.; Webb, Elisabeth B.; Vrtiska, Mark P.; Nilon, Charles H.; Wilhelm Stanis, Sonja A.

    2014-01-01

    We expanded the Nebraska Light Goose Conservation Order (LGCO) harvest survey (NE, USA) in spring 2012 to assess migratory bird hunter opinions regarding future management strategies for controlling light goose populations. Although hunters strongly agreed that population control of light geese was an important wildlife management issue, they were generally unsupportive of wildlife officials using forms of direct control methods to control light goose populations. Respondents who indicated participation in the 2012 LGCO were also less supportive of any form of direct control compared with migratory bird hunters who did not participate in the LGCO. When presented with alternative methods by wildlife officials for future light goose population control, respondents were most supportive of wildlife agencies selectively shooting light geese on migration and wintering areas and least supportive of wildlife officials using bait with approved chemicals to euthanize light geese. A clear understanding of public perception of various potential direct-control options will likely assist wildlife biologists in making informed decisions on how to proceed with population control of light geese.

  15. Analysis of fertility decline in Vietnam in the context of population policy and in comparison with China

    OpenAIRE

    Papřoková, Petra

    2014-01-01

    Analysis of fertility decline in Vietnam in the context of population policy and in comparison with China Abstract Vietnam was unified in 1976 after a 20-year war which left the country devastated. Since that time, Vietnam has experienced dynamic population changes. The Government has introduced an interesting population policy with successful programs. From the end of the 80s until the beginning of the 21st century, Vietnam experienced a huge decline in fertility, one of the most significant...

  16. Forms of density regulation and (quasi-) stationary distributions of population sizes in birds

    DEFF Research Database (Denmark)

    Sæther, Bernt-Erik; Engen, Steinar; Grøtan, Vidar

    2008-01-01

    The theta-logistic model of density regulation is an especially flexible class of density regulation models where different forms of non-linear density regulation can be expressed by only one parameter, u. Estimating the parameters of the thetalogistic model is, however, challenging. This is mainly...... due to the need for information concerning population growth at low densities as well as data on fluctuations around the carrying capacity K in order to estimate the strength of density regulation. Here we estimate parameters of the theta-logistic model for 28 populations of three species of birds...... that have grown from very small population sizes followed by a period of fluctuations around K. We then use these parameters to estimate the quasi-stationary distribution of population size. There were often large uncertainties in these parameters specifying the form of density regulation that were...

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

    Science.gov (United States)

    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

  18. Declines in fertility levels evident in Africa, notes UN Population Fund.

    Science.gov (United States)

    Ofosu-amaah, V

    1998-01-01

    This article reports on the UN Population Fund's (UNFPA) African regional meeting that was held in November 1997. The meeting was attended by an assortment of UNFPA representatives and program staff. This meeting followed up the 1994 Cairo International Conference on Population and Development (ICPD) and 1995 regional meetings on the 1994 Plan of Action. These prior meetings emphasized the link between population and development and the urgency of meeting the needs of individual women and men in a people-centered approach to development, rather than a target oriented one. The 1997 meeting reviewed the progress made toward achieving the goals of the 1994 plan of action by the UNFPA. UNFPA aims to decentralize operations, to play a role in emergency situations, to encourage South-to-South cooperation, to advocate for reproductive rights, and to promote gender equity and women's empowerment. The meeting discussed UNFPA's role in reproductive health, population and development strategies, and advocacy in detail. Participants agreed that there were signs of fertility decline in Africa. Countries are beginning to adopt a reproductive health and rights approach and to address female genital mutilation as a human and reproductive right's issue. Population policies are being changed to include ICPD goals. 32 countries adopted new programs in 1996 and 1997, that integrated the 1994 strategies and selectively focused on issues of concern. Partnerships confirm that population issues are becoming an agenda for all. The major challenge ahead is the mobilization of resources, while dealing with civil strife and political instability.

  19. Dietary Habits and Risk of Kidney Function Decline in an Urban Population.

    Science.gov (United States)

    Liu, Yang; Kuczmarski, Marie Fanelli; Miller, Edgar R; Nava, M Berenice; Zonderman, Alan B; Evans, Michele K; Powe, Neil R; Crews, Deidra C

    2017-01-01

    Explore the association between following a Dietary Approaches to Stop Hypertension (DASH)-accordant diet and kidney end points among urban adults. Prospective cohort study. Healthy Aging in Neighborhoods of Diversity across the Life Span study. A total of 1,534 urban dwelling participants of the Healthy Aging in Neighborhoods of Diversity across the Life Span study with a baseline estimated glomerular filtration rate (eGFR) ≥60 mL/minute/1.73 m 2 . DASH diet accordance determined via a score based on nine target nutrients. Rapid kidney function decline (eGFR decline >3 mL/minute/1.73 m 2 per year), incident chronic kidney disease (CKD) (follow-up eGFR 25%. Participants' mean age was 48 years, and 59% were African-American. Median DASH score was 1.5 (range, 0-8). Over a median of 5 years, 13.4% experienced rapid eGFR decline, including 15.2% among participants not following a DASH-accordant diet (score ≤1) and 12.0% with higher accordance (score >1) (P = .08). Outcomes varied by hypertension status. In multinomial logistic regression models, following adjustment for sociodemographic and clinical factors, including total energy intake, low DASH diet accordance was associated with rapid eGFR decline among participants with hypertension (risk ratio, 1.68; 95% confidence interval: 1.17-2.42) but not among those without hypertension (risk ratio, 0.83; 95% confidence interval: 0.56-1.24; P interaction .001). There was no statistically significant association between DASH diet accordance and incident CKD or eGFR decline >25%. Results were similar when DASH diet accordance was analyzed in tertiles. Among urban adults, low accordance to a DASH-type diet was not associated with incident CKD, but was associated with higher risk of rapid eGFR decline among those with hypertension, yet not among those without hypertension. Further study of dietary patterns as a potential target for improving kidney outcomes among high-risk populations is warranted. Copyright © 2016

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

    Science.gov (United States)

    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.

  1. Z chromosome divergence, polymorphism and relative effective population size in a genus of lekking birds.

    Science.gov (United States)

    Oyler-McCance, S J; Cornman, R S; Jones, K L; Fike, J A

    2015-11-01

    Sex chromosomes contribute disproportionately to species boundaries as they diverge faster than autosomes and often have reduced diversity. Their hemizygous nature contributes to faster divergence and reduced diversity, as do some types of selection. In birds, other factors (mating system and bottlenecks) can further decrease the effective population size of Z-linked loci and accelerate divergence (Fast-Z). We assessed Z-linked divergence and effective population sizes for two polygynous sage-grouse species and compared them to estimates from birds with various mating systems. We found lower diversity and higher FST for Z-linked loci than for autosomes, as expected. The π(Z)/π(A) ratio was 0.38 in Centrocercus minimus, 0.48 in Centrocercus urophasianus and 0.59 in a diverged, parapatric population of C. urophasianus, a broad range given the mating system among these groups is presumably equivalent. The full data set had unequal males and females across groups, so we compared an equally balanced reduced set of C. minimus and individuals pooled from both C. urophasianus subgroups recovering similar estimates: 0.54 for C. urophasianus and 0.38 for C. minimus. We provide further evidence that N(eZ)/N(eA) in birds is often lower than expected under random mating or monogamy. The lower ratio in C. minimus could be a consequence of stronger selection or drift acting on Z loci during speciation, as this species differs strongly from C. urophasianus in sexually selected characters with minimal mitochondrial divergence. As C. minimus also exhibited lower genomic diversity, it is possible that a more severe demographic history may contribute to its lower ratio.

  2. A draft de novo genome assembly for the northern bobwhite (Colinus virginianus reveals evidence for a rapid decline in effective population size beginning in the Late Pleistocene.

    Directory of Open Access Journals (Sweden)

    Yvette A Halley

    Full Text Available Wild populations of northern bobwhites (Colinus virginianus; hereafter bobwhite have declined across nearly all of their U.S. range, and despite their importance as an experimental wildlife model for ecotoxicology studies, no bobwhite draft genome assembly currently exists. Herein, we present a bobwhite draft de novo genome assembly with annotation, comparative analyses including genome-wide analyses of divergence with the chicken (Gallus gallus and zebra finch (Taeniopygia guttata genomes, and coalescent modeling to reconstruct the demographic history of the bobwhite for comparison to other birds currently in decline (i.e., scarlet macaw; Ara macao. More than 90% of the assembled bobwhite genome was captured within 14,000 unique genes and proteins. Bobwhite analyses of divergence with the chicken and zebra finch genomes revealed many extremely conserved gene sequences, and evidence for lineage-specific divergence of noncoding regions. Coalescent models for reconstructing the demographic history of the bobwhite and the scarlet macaw provided evidence for population bottlenecks which were temporally coincident with human colonization of the New World, the late Pleistocene collapse of the megafauna, and the last glacial maximum. Demographic trends predicted for the bobwhite and the scarlet macaw also were concordant with how opposing natural selection strategies (i.e., skewness in the r-/K-selection continuum would be expected to shape genome diversity and the effective population sizes in these species, which is directly relevant to future conservation efforts.

  3. Climate, social factors and research disturbance influence population dynamics in a declining sociable weaver metapopulation.

    Science.gov (United States)

    Altwegg, Res; Doutrelant, Claire; Anderson, Mark D; Spottiswoode, Claire N; Covas, Rita

    2014-02-01

    Population trends are determined by gains through reproduction and immigration, and losses through mortality and emigration. These demographic quantities and resulting population dynamics are affected by different external and internal drivers. We examined how these demographic quantities were affected by weather, research-induced disturbance, local density, colony site and year in a metapopulation of 17 sociable weaver (Philetairus socius) colonies over 17 years of study (4 years for reproduction). Most colonies declined, but at different rates. The four demographic quantities were related to different drivers. Survival strongly varied among years and colonies and was positively related to rainfall and negatively related to extreme temperature (together explaining 30% of variation) and disturbance (measured as number of captures conducted at a colony; 7%). There was a trend for a positive relationship between reproduction and rainfall (50%). Movement was mainly related to local density: individuals were more likely to emigrate from small to large colonies and from colonies that were either well below or above their long-term mean. They were more likely to immigrate into colonies that were nearby, and below their mean size. We then quantified the effects of these relationships on metapopulation dynamics using a multi-site matrix projection model. Rainfall was potentially a strong driver of metapopulation dynamics. In addition, field-work disturbance might have contributed to the decline of this metapopulation but could not explain its full magnitude. Hence, through a combination of analytical methods we were able to obtain information on the main drivers affecting dynamics in a declining metapopulation.

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

    Science.gov (United States)

    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-...

  5. What Happened to Nezara viridula (L.) in the Americas? Possible Reasons to Explain Populations Decline.

    Science.gov (United States)

    Panizzi, A R; Lucini, T

    2016-12-01

    Once abundant in the Americas, the southern green stink bug Nezara viridula (L.) has gradually declined in numbers. Until the 1990s, it was considered the main pest of major crops such as soybean, Glycine max (L.) Merrill, particularly in southern Brazil and southern USA, as well as Argentina, Uruguay, and other countries. In the past 15+ years, a dramatic population decrease was observed to the point of now being considered a secondary pest in these referred countries. In this article, we list and discuss possible reasons which explain the decline in N. viridula population in the Americas. These factors include the following: (1) the steady increase of herbicides used in no-tillage/multiple cropping systems affecting potential hosts such as weeds in crop fields and nearby natural vegetation; (2) the change in cultivation systems, mostly in the Neotropics, favoring other species more adapted to exploit crops in modern day agriculture; (3) competition among several species of stink bugs that colonize major crops; (4) the growing impact of several species of egg parasitoids, some of them laboratory reared and released in crop fields, and other natural enemies (parasitoids and predators); and (5) the impact of global climate change affecting its distribution and biology.

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

    Science.gov (United States)

    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.

  7. Declines revisited: Long-term recovery and spatial population dynamics oftailed frog larvae after wildfire

    Science.gov (United States)

    Hossack, Blake R.; Honeycutt, Richard

    2017-01-01

    Drought has fueled an increased frequency and severity of large wildfires in many ecosystems. Despite an increase in research on wildfire effects on vertebrates, the vast majority of it has focused on short-term (frogs (Ascaphus montanus) in 2001. Surveys during 2004–2005 revealed reduced abundance of larvae in burned streams relative to unburned streams, with greater declines associated with increased fire extent. Rocky Mountain tailed frogs have low vagility and have several unusual life-history traits that could slow population recovery, including an extended larval period (4 years), delayed sexual maturity (6–8 years), and low fecundity ( 58% within 12 years after the fire. We also found moderate synchrony among populations in unburned streams and negative spatial autocorrelation among populations in burned streams. We suspect negative spatial autocorrelation among spatially-clustered burned streams reflected increased post-fire patchiness in resources and different rates of local recovery. Our results add to a growing body of work that suggests populations in intact ecosystems tend to be resilient to habitat changes caused by wildfire. Our results also provide important insights into recovery times of populations that have been negatively affected by severe wildfire.

  8. Further evidence of large-scale population decline and range contraction of the little owl Athene noctua in Central Europe

    Czech Academy of Sciences Publication Activity Database

    Chrenková, M.; Dobrý, M.; Šálek, Martin

    2017-01-01

    Roč. 66, č. 2 (2017), s. 106-116 ISSN 0139-7893 Institutional support: RVO:68081766 Keywords : farmland birds * population trend * distribution * breeding places * agricultural buildings * conservation measures Subject RIV: EG - Zoology OBOR OECD: Zoology Impact factor: 0.739, year: 2016

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

    Science.gov (United States)

    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.

  10. Alarming decline and range reduction of the highly threatened Great ...

    African Journals Online (AJOL)

    A Great Bustard Otis tarda survey carried out in spring 2015 in Morocco confirmed the decline of this highly endangered population. Bustards were only seen at two of the seven leks occupied ten years ago. The total number of birds counted was 40-44, which represents a 40% decline over the last decade. The sex-ratio ...

  11. Prey composition and habitat use of the small and declining Danish population of Little Owl (Athene noctua)

    DEFF Research Database (Denmark)

    Ottesen, N.; Svenne, S.; Sunde, P.

    The population of little owl in Denmark has declined severely during the last 30 years. Many possible causes have been proposed, but the exact cause of this trend is still unknown. Therefore acquirering knowledge about the owls is important....

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

    Science.gov (United States)

    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.

  13. Declining Brown-headed Cowbird (Molothrus ater) populations are associated with landscape-specific reductions in brood parasitism and increases in songbird productivity.

    Science.gov (United States)

    Cox, W Andrew; Thompson, Frank R; Root, Brian; Faaborg, John

    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 parasitism pressure and thus increase productivity of host species. We used 20 years of nest monitoring data from five sites in Missouri across a gradient of landscape forest cover to assess temporal trends in the rate and intensity of brood parasitism for Acadian Flycatchers (Empidonax virescens), Indigo Buntings (Passerina cyanea), and Northern Cardinals (Cardinalis cardinalis). We evaluated whether there were concomitant changes in fledging brood size, nest survival, a combination of the two metrics (i.e., host young produced per nest attempt), and whether such changes were more substantial with decreasing landscape forest cover. Parasitism rates and intensities declined substantially during 1991-2010. Fledging brood size and nest survival rates were positively associated with landscape forest cover, confirming the fragmentation hypothesis for Midwest forest birds. Declining parasitism rates were associated with increased fledging brood sizes, with more pronounced increases as landscape forest cover decreased. Nest survival increased insubstantially across time during laying and incubation, but not during the nestling stage. The best predictor of nest survival was parasitism status, with parasitized nests surviving at lower rates than unparasitized nests. Overall, productivity increased during 1991-2010, with more pronounced increases associated with lower levels of landscape forest cover. The negative effects of cowbirds on nest survival in addition to fledging brood size in less forested landscapes suggest that cowbirds may be a primary cause of forest fragmentation effects on songbird productivity in the Midwest. Our

  14. Declining Brown-headed Cowbird (Molothrus ater populations are associated with landscape-specific reductions in brood parasitism and increases in songbird productivity.

    Directory of Open Access Journals (Sweden)

    W Andrew Cox

    Full Text Available 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 parasitism pressure and thus increase productivity of host species. We used 20 years of nest monitoring data from five sites in Missouri across a gradient of landscape forest cover to assess temporal trends in the rate and intensity of brood parasitism for Acadian Flycatchers (Empidonax virescens, Indigo Buntings (Passerina cyanea, and Northern Cardinals (Cardinalis cardinalis. We evaluated whether there were concomitant changes in fledging brood size, nest survival, a combination of the two metrics (i.e., host young produced per nest attempt, and whether such changes were more substantial with decreasing landscape forest cover. Parasitism rates and intensities declined substantially during 1991-2010. Fledging brood size and nest survival rates were positively associated with landscape forest cover, confirming the fragmentation hypothesis for Midwest forest birds. Declining parasitism rates were associated with increased fledging brood sizes, with more pronounced increases as landscape forest cover decreased. Nest survival increased insubstantially across time during laying and incubation, but not during the nestling stage. The best predictor of nest survival was parasitism status, with parasitized nests surviving at lower rates than unparasitized nests. Overall, productivity increased during 1991-2010, with more pronounced increases associated with lower levels of landscape forest cover. The negative effects of cowbirds on nest survival in addition to fledging brood size in less forested landscapes suggest that cowbirds may be a primary cause of forest fragmentation effects on songbird productivity in the

  15. Recent Honey Bee Colony Declines

    Science.gov (United States)

    2007-06-20

    the scientists who are researching this phenomenon, include but may not be limited to ! parasites , mites, and disease loads in the bees and brood ...thrips; ants; butterflies; moths; bats; and hummingbirds and other birds . 2 Berenbaum, M.R., University of Illinois, Statement before the...bee population losses due to bee pests, parasites , pathogens, and disease. Most notable are declines due to two parasitic mites, the so-called

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

    Directory of Open Access Journals (Sweden)

    Sam C Banks

    Full Text Available 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.

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

    Science.gov (United States)

    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. © 2013 The Fisheries Society of the British Isles.

  18. Use of the superpopulation approach to estimate breeding population size: An example in asynchronously breeding birds

    Science.gov (United States)

    Williams, K.A.; Frederick, P.C.; Nichols, J.D.

    2011-01-01

    Many populations of animals are fluid in both space and time, making estimation of numbers difficult. Much attention has been devoted to estimation of bias in detection of animals that are present at the time of survey. However, an equally important problem is estimation of population size when all animals are not present on all survey occasions. Here, we showcase use of the superpopulation approach to capture-recapture modeling for estimating populations where group membership is asynchronous, and where considerable overlap in group membership among sampling occasions may occur. We estimate total population size of long-legged wading bird (Great Egret and White Ibis) breeding colonies from aerial observations of individually identifiable nests at various times in the nesting season. Initiation and termination of nests were analogous to entry and departure from a population. Estimates using the superpopulation approach were 47-382% larger than peak aerial counts of the same colonies. Our results indicate that the use of the superpopulation approach to model nesting asynchrony provides a considerably less biased and more efficient estimate of nesting activity than traditional methods. We suggest that this approach may also be used to derive population estimates in a variety of situations where group membership is fluid. ?? 2011 by the Ecological Society of America.

  19. West Nile virus and greater sage-grouse: estimating infection rate in a wild bird population.

    Science.gov (United States)

    Walker, Brett L; Naugle, David E; Doherty, Kevin E; Cornish, Todd E

    2007-09-01

    Understanding impacts of disease on wild bird populations requires knowing not only mortality rate following infection, but also the proportion of the population that is infected. Greater sage-grouse (Centrocercus urophasianus) in western North America are known to have a high mortality rate following infection with West Nile virus (WNv), but actual infection rates in wild populations remain unknown. We used rates of WNv-related mortality and seroprevalence from radiomarked females to estimate infection rates in a wild greater sage-grouse population in the Powder River basin (PRB) of Montana and Wyoming from 2003 to 2005. Minimum WNv-related mortality rates ranged from 2.4% to 13.3% among years and maximum possible rates ranged from 8.2% to 28.9%. All live-captured birds in 2003 and 2004 tested seronegative. In spring 2005 and spring 2006, 10.3% and 1.8% respectively, of newly captured females tested seropositive for neutralizing antibodies to WNv. These are the first documented cases of sage-grouse surviving infection with WNv. Low to moderate WNv-related mortality in summer followed by low seroprevalence the following spring in all years indicates that annual infection rates were between 4% and 29%. This suggests that most sage-grouse in the PRB have not yet been exposed and remain susceptible. Impacts of WNv in the PRB in the near future will likely depend more on annual variation in temperature and changes in vector distribution than on the spread of resistance. Until the epizootiology of WNv in sagebrush-steppe ecosystems is better understood, we suggest that management to reduce impacts of WNv focus on eliminating man-made water sources that support breeding mosquitoes known to vector the virus. Our findings also underscore problems with using seroprevalence as a surrogate for infection rate and for identifying competent hosts in highly susceptible species.

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

    Science.gov (United States)

    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".

  1. Doomsday for insects? The alarming decline of insect populations around the world

    Directory of Open Access Journals (Sweden)

    Claudio J. Bidau

    2018-03-01

    Full Text Available Current rates of extinction exceed largely the standard background rate and all living species can be affected. Insects, the most successful group of eukaryotic organisms from their ancient origin almost 480 my ago are no exception. Despite their fundamental roles in all terrestrial and freshwater ecosystems, insects are victims of the anthropogenic intereference (habitat destruction, overharvesting, pathogens, pesticides, pollution, urbanization, transport of invasive species, and greenhouse gases emissions that is causing the declination of their populations around the world. Although most insects are not charismatic as many vertebrates or plants, they deserve the same level of protection as other species with which humans are more concerned. It is a duty for all entomologists to study an implement conservation measures of insect species, and educate the general public about their inmense relevance for the Biosphere.

  2. Hungarian Population Discourses in the Twentieth Century: The Problem of Declining Birth Rates

    Directory of Open Access Journals (Sweden)

    Ildikó Szántó

    2016-01-01

    Full Text Available Falling birth rates had already been recorded as early as the late-eighteenth century in south-western Hungary in the Ormánság. Population loss from low birth rate remained one of the main topics writers and sociologists focused on in the twentieth century. The issue of Hungarian population decline was highlighted among the social ills in the interwar period, which was one of several subjects that divided intellectuals into ‘populists’ and ‘urbanites’. Following the impact of the low birth rate figures in the 1960s, the populists’ views of the 1930s resurfaced in public discourse in the 1960s and 1970s and up to the present day. The concern about the increasing trend of single-child families in rural settlements as well as in urban areas appeared in the various works of Hungarian writers and journalists throughout the previous century. The present paper intends to focus on the intellectual background to the public debates on the population issue, outlining the accounts of the interwar ‘village explorers’ briefly, and the way they are related to the pre-Second World War populist movement. Finally the reappearance of the debates between populists and non-populists of the 1970s is discussed, a debate that is still continuing.

  3. Could Immigration Prevent Population Decline? The Demographic Prospects of Germany Revisited

    Directory of Open Access Journals (Sweden)

    Hannes Weber

    2015-04-01

    Full Text Available Germany has a record of more than 40 years of below-replacement fertility and annual death surplus. Hence, it is commonly accepted that Germany’s population will decline considerably in the coming decades. Recent increases in immigration may, however, challenge the official long-term demographic projections for Germany. This paper assesses the impact of a permanent higher-than-expected level of net immigration to Germany as in the past three years on the projections for population, age structure and ethnic makeup by mid-century.The paper adds a higher immigration variant to the Federal Statistical Office’s latest Coordinated Population Projection and two variants of a (a constant or (b decreasing fertility rate among migrant women. It can be shown that with permanent net migration as high as in recent years (around 300,000 per annum, Germany’s population would not significantly decrease in the coming decades but would rather remain at 80 million until 2050. On the other hand, the sharp rise in the old-age dependency ratio is only mildly weakened by increased immigration rates. This issue is therefore probably best addressed by other (or additional means. The increase in retirees will level off after 2035 in any case. The ethnic makeup of society would be affected to a greater degree than its age composition: The share of first- and second-generation immigrants among the total population is projected to rise to about 35 percent in this scenario (and to above 40 percent if the third generation is also counted.

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

    Science.gov (United States)

    Murray, D.L.; Cox, E.W.; Ballard, W.B.; Whitlaw, Heather 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

  5. Some economic consequences of an ageing and declining population in Denmark.

    Science.gov (United States)

    Leeson, G W

    1983-01-01

    Figures for 1981 indicate that Denmark has a fertility level of 1.45 which has been below replacement level since 1968. In that same time period, natural increase has decreased from over 27,000 in 1968 to only 1354 in 1980 and a negative natural increase in 1981 with deaths outnumbering births by 3001. Even during the depression in the 1930's, net population increase was between 6-9/1000 with a fertility level which hovered around replacement level. At that time, the number of females in the childbearing ages was enough to provide population growth, whereas the number is much less today. Population increase is only 0.3/1000. The national population projections for Denmark for 1981-2010 assume an increase in the fertility level from 1.45-1.70 by 1991 after which it remains constant. The number of 20-39 year olds increased steadily until 1945 after which there was a decline as the cohorts from periods with low fertility levels entered this age group, but this was again followed by a steady increase to the present day. The number of females aged 0-39 years is expected to decrease in all age groups to the year 2000. Those aged 40-59 increased in numbers from 1920 to the mid 1960s, since then they have decreased in number, but an increase is forcast for the remainder of the century. The number of elderly females also increased steadily from 1930-80, from about 200,000 to over 550,000; this is expected to continue until 1990 when a short-term decline will set in. Regarding the economic and social consequences of these trends, it is shown that the present decline in fertility has its origins in a period of low unemployment and its negative growth while there was still relatively low unemployment and economic growth. In 1973 the unemployed rate was 0.9% of the work force and this rose to 9.2% in 1981. The Danish population has aged from one with 1/4 million people aged 60 and over at the turn of the century to about 1 million of that age today. Also, the aged themselves

  6. Breeding season food limitation drives population decline of the Little Owl Athene noctua in Denmark

    DEFF Research Database (Denmark)

    Thorup, Kasper; Sunde, Peter; Jacobsen, Lars B.

    2010-01-01

    Many farmland bird species have declined markedly in Europe in recent decades because of changes in agricultural practice. The specific causes vary and are poorly known for many species. The Little Owl, which feeds extensively on large invertebrates and is strongly associated with the agricultural...... number of fledglings declined from around 3 to size was considerably less. Reproductive parameters were higher closer to habitat types known to be important foraging habitats for Little Owls, and were also positively correlated with the amount...... of seasonally changing land cover (mostly farmland) within a 1-km radius around nests as well as temperatures before and during the breeding season. Experimental food supplementation to breeding pairs increased the proportion of eggs that resulted in fledged young from 27 to 79%, supporting the hypothesis...

  7. Wired: impacts of increasing power line use by a growing bird population

    Science.gov (United States)

    Moreira, Francisco; Encarnação, Vitor; Rosa, Gonçalo; Gilbert, Nathalie; Infante, Samuel; Costa, Julieta; D'Amico, Marcello; Martins, Ricardo C.; Catry, Inês

    2017-02-01

    Power lines are increasingly widespread across many regions of the planet. Although these linear infrastructures are known for their negative impacts on bird populations, through collision and electrocution, some species take advantage of electricity pylons for nesting. In this case, estimation of the net impact of these infrastructures at the population level requires an assessment of trade-offs between positive and negative impacts. We compiled historical information (1958-2014) of the Portuguese white stork Ciconia ciconia population to analyze long-term changes in numbers, distribution range and use of nesting structures. White stork population size increased 660% up to 12000 breeding pairs between 1984 and 2014. In the same period, the proportion of nests on electricity pylons increased from 1% to 25%, likely facilitated by the 60% increase in the length of the very high tension power line grid (holding the majority of the nests) in the stork’s distribution range. No differences in breeding success were registered for storks nesting on electricity pylons versus other structures, but a high risk of mortality by collision and electrocution with power lines was estimated. We discuss the implications of this behavioral change, and of the management responses by power line companies, both for stork populations and for managers.

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

    Science.gov (United States)

    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.

  9. Birds of prey as limiting factors of gamebird populations in Europe: a review.

    Science.gov (United States)

    Valkama, Jari; Korpimäki, Erkki; Arroyo, Beatriz; Beja, Pedro; Bretagnolle, Vincent; Bro, Elisabeth; Kenward, Robert; Mañosa, Santi; Redpath, Stephen M; Thirgood, Simon; Viñuela, Javier

    2005-05-01

    Whether predators can limit their prey has been a topic of scientific debate for decades. Traditionally it was believed that predators take only wounded, sick, old or otherwise low-quality individuals, and thus have little impact on prey populations. However, there is increasing evidence that, at least under certain circumstances, vertebrate predators may indeed limit prey numbers. This potential role of predators as limiting factors of prey populations has created conflicts between predators and human hunters, because the hunters may see predators as competitors for the same resources. A particularly acute conflict has emerged over the past few decades between gamebird hunters and birds of prey in Europe. As a part of a European-wide research project, we reviewed literature on the relationships between birds of prey and gamebirds. We start by analysing available data on the diets of 52 European raptor and owl species. There are some 32 species, mostly specialist predators feeding on small mammals, small passerine birds or insects, which never or very rarely include game animals (e.g. hares, rabbits, gamebirds) in their diet. A second group (20 species) consists of medium-sized and large raptors which prey on game, but for which the proportion in the diet varies temporally and spatially. Only three raptor species can have rather large proportions of gamebirds in their diet, and another seven species may utilise gamebirds locally to a great extent. We point out that the percentage of a given prey species in the diet of an avian predator does not necessarily reflect the impact of that predator on densities of prey populations. Next, we summarise available data on the numerical responses of avian predators to changing gamebird numbers. In half of these studies, no numerical response was found, while in the remainder a response was detected such that either raptor density or breeding success increased with density of gamebirds. Data on the functional responses of

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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...

  12. Rapid population decline in red knots : fitness consequences of decreased refuelling rates and late arrival in Delaware Bay

    NARCIS (Netherlands)

    Baker, AJ; Gonzalez, PM; Piersma, T; Niles, LJ; do Nascimento, IDS; Atkinson, PW; Clark, NA; Minton, CDT; Peck, MK; Aarts, G

    2004-01-01

    Most populations of migrant shorebirds around the world are in serious decline, suggesting that vital condition-dependent rates such as fecundity and annual survival are being affected globally. A striking example is the red knot (Calidris canutus rufa) population wintering in Tierra del Fuego,

  13. A Demographic Model to Evaluate Population Declines in the Endangered Streaked Horned Lark

    Directory of Open Access Journals (Sweden)

    Alaine F. Camfield

    2011-12-01

    Full Text Available The Streaked Horned Lark (Eremophila alpestris strigata is listed as endangered by the State of Washington, USA and by Canada under the Species at Risk Act and is also classified as a federal candidate for listing under the Endangered Species Act in the USA. A substantial portion of Streaked Horned Lark habitat has been lost or degraded, and range contraction has occurred in Oregon, Washington, and British Columbia. We estimate the vital rates (fecundity, adult and juvenile survival and population growth rate (λ for Streaked Horned Larks breeding in Washington, USA and conduct a Life-Stage Simulation Analysis (LSA to evaluate which vital rate has the greatest influence on λ. We simulated changes in the three vital rates to examine how much they would need to be adjusted either independently or in concert to achieve a stable Streaked Horned Lark population (λ = 1. We also evaluated which fecundity component (the number of fledglings per egg laid or renesting interval had the greatest impact on λ. The estimate of population growth suggests that Streaked Horned Larks in Washington are declining rapidly (λ = 0.62 ± 0.10 and that local breeding sites are not sustainable without immigration. The LSA results indicate that adult survival had the greatest influence on λ, followed by juvenile survival and fecundity. However, increases in vital rates led to λ = 1 only when adult survival was raised from 0.47 to 0.85, juvenile survival from 0.17 to 0.58, and fecundity from 0.91 to 3.09. Increases in breeding success and decreases in the renesting interval influenced λ similarly; however, λ did not reach 1 even when breeding success was raised to 100% or renesting intervals were reduced to 1 day. Only when all three vital rates were increased simultaneously did λ approach 1 without requiring highly unrealistic increases in each vital rate. We conclude that conservation activities need to target all or multiple vital rates to be successful. The

  14. Epidemiology of the emergent disease Paridae pox in an intensively studied wild bird population.

    Directory of Open Access Journals (Sweden)

    Shelly Lachish

    Full Text Available Paridae pox, a novel avipoxvirus infection, has recently been identified as an emerging infectious disease affecting wild tit species in Great Britain. The incursion of Paridae pox to a long-term study site where populations of wild tits have been monitored in detail for several decades provided a unique opportunity to obtain information on the local-scale epidemiological characteristics of this novel infection during a disease outbreak. Using captures of >8000 individual birds, we show that, within two years of initial emergence, Paridae pox had become established within the population of great tits (Parus major reaching relatively high peak prevalence (10%, but was far less prevalent (<1% in sympatric populations of several other closely related, abundant Paridae species. Nonlinear smoothing models revealed that the temporal pattern of prevalence among great tits was characterised by within-year fluctuations indicative of seasonal forcing of infection rates, which was likely driven by multiple environmental and demographic factors. There was individual heterogeneity in the course of infection and, although recovery was possible, diseased individuals were far less likely to be recaptured than healthy individuals, suggesting a survival cost of infection. This study demonstrates the value of long-term monitoring for obtaining key epidemiological data necessary to understand disease dynamics, spread and persistence in natural populations.

  15. Migratory connectivity and population-specific migration routes in a long-distance migratory bird.

    Science.gov (United States)

    Trierweiler, Christiane; Klaassen, Raymond H G; Drent, Rudi H; Exo, Klaus-Michael; Komdeur, Jan; Bairlein, Franz; Koks, Ben J

    2014-03-07

    Knowledge about migratory connectivity, the degree to which individuals from the same breeding site migrate to the same wintering site, is essential to understand processes affecting populations of migrants throughout the annual cycle. Here, we study the migration system of a long-distance migratory bird, the Montagu's harrier Circus pygargus, by tracking individuals from different breeding populations throughout northern Europe. We identified three main migration routes towards wintering areas in sub-Saharan Africa. Wintering areas and migration routes of different breeding populations overlapped, a pattern best described by 'weak (diffuse) connectivity'. Migratory performance, i.e. timing, duration, distance and speed of migration, was surprisingly similar for the three routes despite differences in habitat characteristics. This study provides, to our knowledge, a first comprehensive overview of the migration system of a Palaearctic-African long-distance migrant. We emphasize the importance of spatial scale (e.g. distances between breeding populations) in defining patterns of connectivity and suggest that knowledge about fundamental aspects determining distribution patterns, such as the among-individual variation in mean migration directions, is required to ultimately understand migratory connectivity. Furthermore, we stress that for conservation purposes it is pivotal to consider wintering areas as well as migration routes and in particular stopover sites.

  16. Selenium teratogenesis in natural populations of aquatic birds in central California

    Science.gov (United States)

    Hoffman, D.J.; Ohlendorf, H.M.; Aldrich, T.W.

    1988-01-01

    The frequency and types of malformations are described that were encountered during the spring of 1983 in a natural population of aquatic birds exposed to agricultural drainwater ponds and food items containing high concentrations of selenium in central California. A total of 347 nests of aquatic birds containing 1,681 eggs was selected for study at Kesterson Reservoir located in the Kesterson National Wildlife Refuge (NWR), Merced County, California. Embryos collected during incubation or from eggs that failed to hatch were examined to determine the age at death and presence of malformations. Embryonic death was generally high; approximately 17?60% of the nests of different species contained at least one dead embryo. The incidence of malformed embryos was also high; approximately 22?65% of the nests where at least two embryos were examined contained abnormal embryos. American coots (Fulica americana) and black-necked stilts (Himantopus mexicanus) experienced the highest incidence of malformed embryos. For all species, the average percentage of eggs containing dead or live abnormal embryos was 16.1 whereas the average percentage containing live abnormal embryos was 10.7. Multiple gross malformations of the eyes, brain, and feet were often present. Brain defects included hydrocephaly and exencephaly. Eye defects included both unilateral and bilateral anophthalmia and microphthalmia. Eye and foot defects with ectrodactyly and swollen joints were the most common in coots. Beak defects also occurred frequently and most often included incomplete development of the lower beak of ducks (Anas spp.) and stilts. Wing and leg defects were most prevalent in stilts and ducks, with ectromelia and amelia most prevalent in stilts. Other malformations occurring at lower frequencies included enlarged hearts with thin ventricular walls, liver hypopiasia, and gastroschisis. Based upon simultaneous examination of a control population of aquatic birds of the same species and published

  17. Population trends of grassland birds in North America are linked to the prevalence of an agricultural epizootic in Europe.

    Science.gov (United States)

    Nocera, Joseph J; Koslowsky, Hannah M

    2011-03-22

    Globalization of trade has dramatic socioeconomic effects, and, intuitively, significant ecological effects should follow. However, few quantitative examples exist of the interrelationship of globalization, socioeconomics, and ecological patterns. We present a striking illustration of a cascade in which bovine spongiform encephalopathy (BSE; "mad cow disease") outbreaks in Europe exerted pressure on global beef markets, subsequently affecting North American hayfields and grassland bird populations. We examined competing models, which linked the prevalence of BSE in five focal countries, volume of beef exports to those countries from North America, and the amount of hayfield harvested and the abundance of grassland birds in North America. We found that (i) imports from North America increased 1 y after BSE outbreaks; (ii) probably because fewer cattle remained, the hay harvest in North America was reduced 2 y after the outbreak; (iii) the reduced hay harvest yielded a positive response in grassland bird populations 3 y after the outbreak.

  18. The erratic mitochondrial clock: variations of mutation rate, not population size, affect mtDNA diversity across birds and mammals

    Directory of Open Access Journals (Sweden)

    Galtier Nicolas

    2009-03-01

    Full Text Available Abstract Background During the last ten years, major advances have been made in characterizing and understanding the evolution of mitochondrial DNA, the most popular marker of molecular biodiversity. Several important results were recently reported using mammals as model organisms, including (i the absence of relationship between mitochondrial DNA diversity and life-history or ecological variables, (ii the absence of prominent adaptive selection, contrary to what was found in invertebrates, and (iii the unexpectedly large variation in neutral substitution rate among lineages, revealing a possible link with species maximal longevity. We propose to challenge these results thanks to the bird/mammal comparison. Direct estimates of population size are available in birds, and this group presents striking life-history trait differences with mammals (higher mass-specific metabolic rate and longevity. These properties make birds the ideal model to directly test for population size effects, and to discriminate between competing hypotheses about the causes of substitution rate variation. Results A phylogenetic analysis of cytochrome b third-codon position confirms that the mitochondrial DNA mutation rate is quite variable in birds, passerines being the fastest evolving order. On average, mitochondrial DNA evolves slower in birds than in mammals of similar body size. This result is in agreement with the longevity hypothesis, and contradicts the hypothesis of a metabolic rate-dependent mutation rate. Birds show no footprint of adaptive selection on cytochrome b evolutionary patterns, but no link between direct estimates of population size and cytochrome b diversity. The mutation rate is the best predictor we have of within-species mitochondrial diversity in birds. It partly explains the differences in mitochondrial DNA diversity patterns observed between mammals and birds, previously interpreted as reflecting Hill-Robertson interferences with the W

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

    Science.gov (United States)

    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 (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 lower extinction

  20. The use of population viability analysis to identify possible factors contributing to the decline of a rare ungulate population in south-eastern Zimbabwe

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    Simon D. Capon

    2013-02-01

    Full Text Available Populations that are vulnerable to decline are of particular concern to wildlife managers and uncovering the mechanisms responsible for downward trends is a crucial step towards developing future viable populations. The aims of this study were to better understand the mechanisms behind the historic decline of the sable antelope, Hippotragus niger, population at the Malilangwe Wildlife Reserve (MWR, to assess its future viability and to use this analysis to determine key areas of breakdown in population growth and link these to potential limiting factors. VORTEX, a population viability model was used to assess the future viability of the sable antelope population and a sensitivity analysis was applied to identify the key areas of breakdown in growth. The sable population is currently viable, but remains highly vulnerable to changes in adult female survival, a factor which had the greatest influence on overall population fitness. Lion predation, impacting on the adult segment of the population, appeared to be the main factor responsible for the historic decline at the MWR.Conservation implications: Sable generally occur at low densities in the lowveld region of Zimbabwe and, as such, populations are vulnerable to increases in mortality rates. The role of lions in driving the decline at the MWR suggests a need to control their numbers and develop prey refuges through improved management of artificial water.

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

    Science.gov (United States)

    Murray, D.L.; Cox, E.W.; Ballard, W.B.; Whitlaw, Heather 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

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

    Science.gov (United States)

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

    2015-01-01

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

  3. Bridging the gap between habitat-modeling research and bird conservation with dynamic landscape and population models

    Science.gov (United States)

    Frank R., III Thompson

    2009-01-01

    Habitat models are widely used in bird conservation planning to assess current habitat or populations and to evaluate management alternatives. These models include species-habitat matrix or database models, habitat suitability models, and statistical models that predict abundance. While extremely useful, these approaches have some limitations.

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

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    Mohd Ridzuan Mohd Abd Razak

    .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.

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

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    Rwegoshora Rwehumbiza T

    2011-07-01

    Full Text Available Abstract 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.

  6. Waist Circumference, Not Body Mass Index, Is Associated with Renal Function Decline in Korean Population: Hallym Aging Study

    Science.gov (United States)

    Oh, Hyunju; Quan, Shan Ai; Jeong, Jin-Young; Jang, Soong-Nang; Lee, Jung Eun; Kim, Dong-Hyun

    2013-01-01

    Background Prospective investigation of obesity and renal function decline in Asia is sparse. We examined the associations of body mass index (BMI) and waist circumference (WC) with renal function decline in a prospective study of Korean population. Methods A total of 454 participants who had baseline estimated glomerular filtration rate (eGFR) levels of more than 60 mL/min/1.73 m2 in Hallym Aging Study (HAS) were included and followed for 6 years. Renal function decline was defined as follows: (1) an eGFR decline ≥3 mL/min/1.73 m2/year (n = 82 cases); (2) an eGFR decrease of 20% or greater (n = 87 cases) at follow-up; (3) an eGFR decrease of 20% greater at follow-up or eGFR decline ≥3 mL/min/1.73 m2/year (n = 91 cases); and (4) an eGFR 95 cm in men or >90 cm in women with ≤90 cm in men or ≤85 cm in women, ORs (95% CIs) ranged from 2.31 (1.14–4.69) to 2.78 (1.19–6.50) for the 4 definitions of renal function decline (all p-values for trend Korean population. Our results provide important evidence that simple measurement of central fat deposition rather than BMI could predict decline in renal function in Korean population. PMID:23536858

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

    Science.gov (United States)

    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

  8. Dynamics of a recovering Arctic bird population: the importance of climate, density dependence, and site quality

    Science.gov (United States)

    Bruggeman, Jason E.; Swem, Ted; Andersen, David E.; Kennedy, Patricia L.; Nigro, Debora A.

    2015-01-01

    Intrinsic and extrinsic factors affect vital rates and population-level processes, and understanding these factors is paramount to devising successful management plans for wildlife species. For example, birds time migration in response, in part, to local and broadscale climate fluctuations to initiate breeding upon arrival to nesting territories, and prolonged inclement weather early in the breeding season can inhibit egg-laying and reduce productivity. Also, density-dependent regulation occurs in raptor populations, as territory size is related to resource availability. Arctic Peregrine Falcons (Falco peregrinus tundrius; hereafter Arctic peregrine) have a limited and northern breeding distribution, including the Colville River Special Area (CRSA) in the National Petroleum Reserve–Alaska, USA. We quantified influences of climate, topography, nest productivity, prey habitat, density dependence, and interspecific competition affecting Arctic peregrines in the CRSA by applying the Dail-Madsen model to estimate abundance and vital rates of adults on nesting cliffs from 1981 through 2002. Arctic peregrine abundance increased throughout the 1980s, which spanned the population's recovery from DDT-induced reproductive failure, until exhibiting a stationary trend in the 1990s. Apparent survival rate (i.e., emigration; death) was negatively correlated with the number of adult Arctic peregrines on the cliff the previous year, suggesting effects of density-dependent population regulation. Apparent survival and arrival rates (i.e., immigration; recruitment) were higher during years with earlier snowmelt and milder winters, and apparent survival was positively correlated with nesting season maximum daily temperature. Arrival rate was positively correlated with average Arctic peregrine productivity along a cliff segment from the previous year and initial abundance was positively correlated with cliff height. Higher cliffs with documented higher productivity (presumably

  9. Population Densities of Birds Breeding in Urbanized Habitats in the Grabiszyn District in the City of Wrocław

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    Kopij Grzegorz

    2014-11-01

    Full Text Available Studies were carried out in 2010 by mean of simplified version of the mapping method. The study area (395 ha was located close to the city centre. It comprised a mosaic of urbanized habitats, with a clear dominance of green areas, such as parks (41.1 ha, gardens, cemeteries and tree clumps. A total of 48 breeding bird species were recorded in the whole study area. The most common (<25 pairs/100 ha were Passer domesticus, Passer montanus, Sturnus vulgaris, Parus caeruleus, Parus major, Apus apus and Columba livia. Numerous (7-15 pairs/100 ha were also the following species: Columba palumbus, Turdus pilaris, Sylvia atricapilla, Serinus serinus, Turdus merula and Pica pica. Insectivorous birds were the most common birds constituting 63.3%, and granivorous -32.6% of all pairs recorded. Most birds nested in tree holes (39.3%, in/on buildings (30.2% and in trees/shrubs (25.6%. Distribution of breeding pairs of 23 bird species was presented on maps. Population trends for 17 species were documented. Rapid increase in numbers of Turdus pilaris, Corvus cornix and Phoenicurus phoenicurus and decrease of Pica pica were recorded.

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

    Science.gov (United States)

    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. Adaptive landscapes and density-dependent selection in declining salmonid populations: going beyond numerical responses to human disturbance

    OpenAIRE

    Einum, Sigurd; Robertsen, Grethe; Fleming, Ian A

    2008-01-01

    Theory suggests an important role for population density in shaping adaptive landscapes through density-dependent selection. Here, we identify five methodological approaches for studying such selection, review the existing empirical evidence for it, and ask whether current declines in abundance can be expected to trigger evolutionary responses in salmonid fishes. Across taxa we find substantial amounts of evidence for population density influencing the location of adaptive peaks for a range o...

  12. A 20-year recount of bird populations along a Great Basin elevational gradient

    Science.gov (United States)

    John Woodyard; Melissa Renfro; Bruce L. Welch; Kristina Heister

    2003-01-01

    During 1981 and 1982, Dean E. Medin conducted bird censuses along an elevational gradient (5,250 to 11, 400 feet) near and on Wheeler Peak of east-central Nevada. Twenty years later we conducted bird census on seven of his 12 plots. Data from the bristlecone pine - Pinus longaeva - plot were collected in 1981 but not published (data on file with the...

  13. Epidemiological study of Newcastle disease in backyard poultry and wild bird populations in Switzerland.

    Science.gov (United States)

    Schelling, E; Thur, B; Griot, C; Audige, L

    1999-06-01

    Blood samples and cloacal swabs from poultry were collected in 107 small chicken flocks and 62 pure-bred poultry flocks to determine their status regarding Newcastle disease virus (NDV) infection. A questionnaire emphasizing potential contacts of poultry with wild birds and management practices associated with NDV infection was completed for each flock. Additionally, 1576 wild bird carcasses of 115 different bird species were collected from hunters and taxidermists. Poultry sera and tissue fluids of wild birds were tested for NDV antibodies using a blocking ELISA. Cloacal swabs were subjected to reverse transcription polymerase chain reaction (RT-PCR) for NDV genome detection. In-herd NDV seroprevalences between 5 and 29% were found in one small chicken flock, as well as in four pure-bred poultry flocks. NDV antibody positive wild birds were found in 10.2% of all wild birds examined. Highest proportions (i.e. 15%) of positive birds per species were found among sparrowhawks, kites, tawny owls, eagle owls, barn owls, cuckoos, swifts, cormorants and grebes. No NDV genome was detected in cloacal swabs. This study suggests that buying eggs or poultry abroad and exchanging poultry within the country were factors, more important than wild birds, to explain the higher NDV seropositivity in pure-bred poultry flocks.

  14. A spatially explicit model for estimating risks of pesticide exposure to bird populations

    Science.gov (United States)

    Pesticides are used widely in US agriculture and may affect non-target organisms, including birds. Some pesticide classes (e.g., acetylcholinesterase inhibitors) are known or suspected to cause direct mortality to birds, while others (e.g., synthetic pyrethroids, neonicotinoids) ...

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    Lodé, Thierry; Cormier, Jean-Paul; Le Jacques, Dominique

    2001-12-01

    Populations of threatened species, especially predators at the top of the food chain, may be affected by anthropic pressures. The endangered western population of European mink Mustela lutreola has shown a large decline over 50% of its natural range. M. lutreola disappeared from northwestern France between 1984 and 1997, and the decline was associated with an increase in mustelid trapping, changes in watercourse quality, and habitat modifications due to agricultural practices. The pattern of decline showed a fragmentation restricting the minks into very small areas. Trapping was the first known cause of mortality. Although feral American mink Mustela vison may compete with autochthonous carnivores, M. lutreola had disappeared from streams before the introduction of the American species, suggesting that competitive interactions were not responsible. Furthermore, American mink has never been found or has remained rare in 62.4% of the area from which M. lutreola has disappeared. During the past 25 years, permanent grassland surfaces were reduced by 40%, whereas fodder culture increased by 470%, causing considerable habitat changes. Furthermore, 55.7% of water courses were classified as being of bad quality or polluted. Therefore, our data suggests that a conjunction of intensive trapping, alterations in water quality and habitat modification was critical for the European mink's decline. Although there are difficulties in ascribing specific cause to distribution changes in a top predator, this decline can be regarded as an indication for anthropic pressures on natural habitats.

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

    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

  19. PANTAI PASIR PADI (PADDY SAND BEACH OF BANGKA ISLAND; CRABS (Scopimera sp POPULATION, FEEDING BEHAVIOUR AND THEIR BIRD PREDATOR

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    Hanifa Marisa

    2016-11-01

    Full Text Available An observation about beach crab (Scopimera sp population, their feeding behaviour and predator bird had been done at October 9 th, 2014 in Pantai Pasir Padi, Eastern Bangka Island beach, near Pangkal Pinang town. Ten 1 meter square plots were put at sandy beach and number of Scopimera sp be counted by the number of their hole nest home. Their feeding behaviour observed directly by eye-watching and video making. The threatening of bird predator was noted too.  The investigation find out that the mean of crabs population is 17 individu/m2 .  They come out from home hole for feeding around by sieving wet sand that be taken by front legs, obsorb organic nutrious material by mouth and kick residual sand to behind legs, move it as a small sand ball to right of left back side.  Production of small ball sand were about 15 - 30 balls /per minute. For making the nest hole, bigger sand ball were produced about 7 – 9 ball/minute; ball colour is same with under layer beach sand; quite grey. The crabs run instinctivey fast, when the threat come from their natural enemy, predator bird, Actitis hypoleucos.  Bird searching behaviour look adapted to the fast run of crab. Keywords: Scopimera sp, Actitis hypoleucos, small sand ball, predator, behaviour

  20. Supplementary feeding of wild birds indirectly affects ground beetle populations in suburban gardens.

    Science.gov (United States)

    Orros, Melanie E; Thomas, Rebecca L; Holloway, Graham J; Fellowes, Mark D E

    Supplementary feeding of wild birds by domestic garden-holders is a globally widespread and popular form of human-wildlife interaction, particularly in urban areas. Vast amounts of energy are thus being added to garden ecosystems. However, the potential indirect effects of this activity on non-avian species have been little studied to date, with the only two previous studies taking place under experimentally manipulated conditions. Here we present the first evidence of a localised depletive effect of wild bird feeding on ground beetles (Coleoptera: Carabidae) in suburban gardens under the usual feeding patterns of the garden-holders. We trapped significantly fewer ground beetles directly under bird-feeding stations than in matched areas of habitat away from feeders. Video analysis also revealed significantly higher activity by ground-foraging birds under the feeding stations than in the control areas. Small mammal trapping revealed no evidence that these species differ in abundance between gardens with and without bird feeders. We therefore suggest that local increases in ground-foraging activity by bird species whose diets encompass arthropods as well as seed material are responsible for the reduction in ground beetle numbers. Our work therefore illustrates that providing food for wild birds can have indirect negative effects on palatable prey species under typical conditions.

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

    Directory of Open Access Journals (Sweden)

    Thomas E Ingersoll

    Full Text Available 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

  2. Integrating Breeding Bird Survey and demographic data to estimate Wood Duck population size in the Atlantic Flyway

    Science.gov (United States)

    Zimmerman, Guthrie S.; Sauer, John; Boomer, G. Scott; Devers, Patrick K.; Garrettson, Pamela R.

    2017-01-01

    The U.S. Fish and Wildlife Service (USFWS) uses data from the North American Breeding Bird Survey (BBS) to assist in monitoring and management of some migratory birds. However, BBS analyses provide indices of population change rather than estimates of population size, precluding their use in developing abundance-based objectives and limiting applicability to harvest management. Wood Ducks (Aix sponsa) are important harvested birds in the Atlantic Flyway (AF) that are difficult to detect during aerial surveys because they prefer forested habitat. We integrated Wood Duck count data from a ground-plot survey in the northeastern U.S. with AF-wide BBS, banding, parts collection, and harvest data to derive estimates of population size for the AF. Overlapping results between the smaller-scale intensive ground-plot survey and the BBS in the northeastern U.S. provided a means for scaling BBS indices to the breeding population size estimates. We applied these scaling factors to BBS results for portions of the AF lacking intensive surveys. Banding data provided estimates of annual survival and harvest rates; the latter, when combined with parts-collection data, provided estimates of recruitment. We used the harvest data to estimate fall population size. Our estimates of breeding population size and variability from the integrated population model (N̄ = 0.99 million, SD = 0.04) were similar to estimates of breeding population size based solely on data from the AF ground-plot surveys and the BBS (N̄ = 1.01 million, SD = 0.04) from 1998 to 2015. Integrating BBS data with other data provided reliable population size estimates for Wood Ducks at a scale useful for harvest and habitat management in the AF, and allowed us to derive estimates of important demographic parameters (e.g., seasonal survival rates, sex ratio) that were not directly informed by data.

  3. The use of data and knowledge about bird numbers and population demography for the conservation and management of migratory birds

    DEFF Research Database (Denmark)

    Fox, Anthony David

    2011-01-01

    Flyway level assessment of changes in abundance is essential to assess the effectiveness of conservation and management. Additional data on demographic rates (reproduction and survival) is needed to underpin the causes of changes. Data on immigration or emigration are helpful but more difficult t...... to obtain. There should be more attention to the effects of hunting on population sizes. Much can be achieved if citizen science (counters are almost all volunteers!) is well organised but on the basis of good professional leadership to get the maximum out of it....

  4. Bird communities and biomass yields in potential bioenergy grasslands.

    Science.gov (United States)

    Blank, Peter J; Sample, David W; Williams, Carol L; Turner, Monica G

    2014-01-01

    Demand for bioenergy is increasing, but the ecological consequences of bioenergy crop production on working lands remain unresolved. Corn is currently a dominant bioenergy crop, but perennial grasslands could produce renewable bioenergy resources and enhance biodiversity. Grassland bird populations have declined in recent decades and may particularly benefit from perennial grasslands grown for bioenergy. We asked how breeding bird community assemblages, vegetation characteristics, and biomass yields varied among three types of potential bioenergy grassland fields (grass monocultures, grass-dominated fields, and forb-dominated fields), and assessed tradeoffs between grassland biomass production and bird habitat. We also compared the bird communities in grassland fields to nearby cornfields. Cornfields had few birds compared to perennial grassland fields. Ten bird Species of Greatest Conservation Need (SGCN) were observed in perennial grassland fields. Bird species richness and total bird density increased with forb cover and were greater in forb-dominated fields than grass monocultures. SGCN density declined with increasing vertical vegetation density, indicating that tall, dense grassland fields managed for maximum biomass yield would be of lesser value to imperiled grassland bird species. The proportion of grassland habitat within 1 km of study sites was positively associated with bird species richness and the density of total birds and SGCNs, suggesting that grassland bioenergy fields may be more beneficial for grassland birds if they are established near other grassland parcels. Predicted total bird density peaked below maximum biomass yields and predicted SGCN density was negatively related to biomass yields. Our results indicate that perennial grassland fields could produce bioenergy feedstocks while providing bird habitat. Bioenergy grasslands promote agricultural multifunctionality and conservation of biodiversity in working landscapes.

  5. Bird communities and biomass yields in potential bioenergy grasslands.

    Directory of Open Access Journals (Sweden)

    Peter J Blank

    Full Text Available Demand for bioenergy is increasing, but the ecological consequences of bioenergy crop production on working lands remain unresolved. Corn is currently a dominant bioenergy crop, but perennial grasslands could produce renewable bioenergy resources and enhance biodiversity. Grassland bird populations have declined in recent decades and may particularly benefit from perennial grasslands grown for bioenergy. We asked how breeding bird community assemblages, vegetation characteristics, and biomass yields varied among three types of potential bioenergy grassland fields (grass monocultures, grass-dominated fields, and forb-dominated fields, and assessed tradeoffs between grassland biomass production and bird habitat. We also compared the bird communities in grassland fields to nearby cornfields. Cornfields had few birds compared to perennial grassland fields. Ten bird Species of Greatest Conservation Need (SGCN were observed in perennial grassland fields. Bird species richness and total bird density increased with forb cover and were greater in forb-dominated fields than grass monocultures. SGCN density declined with increasing vertical vegetation density, indicating that tall, dense grassland fields managed for maximum biomass yield would be of lesser value to imperiled grassland bird species. The proportion of grassland habitat within 1 km of study sites was positively associated with bird species richness and the density of total birds and SGCNs, suggesting that grassland bioenergy fields may be more beneficial for grassland birds if they are established near other grassland parcels. Predicted total bird density peaked below maximum biomass yields and predicted SGCN density was negatively related to biomass yields. Our results indicate that perennial grassland fields could produce bioenergy feedstocks while providing bird habitat. Bioenergy grasslands promote agricultural multifunctionality and conservation of biodiversity in working landscapes.

  6. Effects of low-density housing development on shrubland birds in western Massachusetts

    Science.gov (United States)

    Scott Schlossberg; David I. King; Richard B. Chandler

    2011-01-01

    Housing development in rural areas is the fastest-growing type of land use in the U.S. For birds, development near natural habitats is a problem because it can reduce abundances and nesting success and increase brood parasitism by brown-headed cowbirds (Molothrus ater). In southern New England, populations of shrubland birds are declining rapidly...

  7. Genetic structure and evidence for recent population decline in Eurasian otter populations in the Czech and Slovak Republics: implications for conservation

    DEFF Research Database (Denmark)

    Hájková, P.; Pertoldi, C.; Ukendt, Zemanová

    2007-01-01

    Over the latter part of the 20th century, Eurasian otter Lutra lutra populations suffered dramatic declines, resulting in extinction or fragmentation of populations in many western and central European countries. Part of the Czech otter population became totally isolated while the Slovak populati...... that they remain a strongly protected species in both countries. The spreading and re-connection of otter populations observed recently is essential for the future health of the populations, and should be supported through habitat conservation.......Over the latter part of the 20th century, Eurasian otter Lutra lutra populations suffered dramatic declines, resulting in extinction or fragmentation of populations in many western and central European countries. Part of the Czech otter population became totally isolated while the Slovak population...... and faecal samples. A relatively high level of genetic differentiation was found between the Czech and Slovak populations (FST=0.154, P=0.0002), supported by a perfect assignment in Bayesian cluster analysis. Both the Czech and Slovak populations showed significant heterozygosity excess (assuming an infinite...

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    Vibhu Prakash

    Full Text Available 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.

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

    Directory of Open Access Journals (Sweden)

    Abinash Padhi

    2010-12-01

    Full Text Available 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 (k increased from early to late phases in dual infected cats due primarily to a decrease in transversions whereas in single infected cats, k 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.

  11. THE WINTER POPULATION OF BIRDS OF ROADSIDE SPACES OF CENTRAL CISCAUCASIA

    Directory of Open Access Journals (Sweden)

    I. V. MAKIYAN

    2010-01-01

    Full Text Available The article provides an analysis of winter roadside avifauna of the Central Сiscaucasia. Observations of birds on the highways are currently one of the most effective, advanced and accessible methods of accounting.

  12. Effect of Early Referral to Specialist in Dementia on Institutionalization and Functional Decline: Findings from a Population-Based Study.

    Science.gov (United States)

    Pimouguet, Clément; Le-Goff, Mélanie; Rizzuto, Debora; Berr, Claudine; Leffondré, Karen; Pérès, Karine; Dartigues, Jean FranÇois; Helmer, Catherine

    2016-01-01

    Although early diagnosis has been hypothesized to benefit both patients and caregivers, until now studies evaluating the effect of early dementia diagnosis are lacking. To investigate the influence of early specialist referral for dementia on the risk of institutionalization and functional decline in Activity of Daily Living (ADL). Incident dementia cases were screened in a prospective population-based cohort, the Three-City Study, and initial specialist consultation for cognitive complaint was assessed at dementia diagnosis. Proportional hazard regression and illness-death models were used to test the association between specialist referral and, respectively, institutionalization and functional decline. Only one third of the incident individuals with dementia had consulted a specialist for cognitive problems early (36%). After adjustment on potential confounders (including cognitive and functional decline) and competing risk of death, participants who had consulted a specialist early in the disease course presented a higher rate of being institutionalized than those who did not (Hazard Ratio = 2.00, 95% Confidence Interval (CI): 1.09- 3.64). But early specialist referral was not associated with further functional decline (HR = 1.09, 95% CI: 0.71- 1.67). Early specialist referral in dementia is associated with increased risk of institutionalization but not with functional decline in ADL. These findings suggest that early care referral in dementia may be a marker of concern for patients and/or caregivers; subsequent medical and social care could be suboptimal or inappropriate to allow patients to stay longer at home.

  13. The decline of the Nile crocodile population in Loskop Dam, Olifants ...

    African Journals Online (AJOL)

    The apparent decline in the number of Nile crocodiles present in the Loskop Dam prompted a study to determine the number, size and distribution of Nile crocodiles now present in the reservoir. The number of crocodiles in the Loskop Dam was surveyed using aerial counts and spotlight counts. Surveys revealed the ...

  14. The use of population viability analysis to identify possible factors contributing to the decline of a rare ungulate population in south-eastern Zimbabwe

    Directory of Open Access Journals (Sweden)

    Simon D. Capon

    2013-04-01

    Conservation implications: Sable generally occur at low densities in the lowveld region of Zimbabwe and, as such, populations are vulnerable to increases in mortality rates. The role of lions in driving the decline at the MWR suggests a need to control their numbers and develop prey refuges through improved management of artificial water.

  15. Late Holocene Decline of Beech Populations in the Central Great Lakes Region: Drought- Induced Vegetation Change in a Humid Region.

    Science.gov (United States)

    Booth, R. K.; Jackson, S. T.; Taylor, M.; Pendall, E.; Sousa, V. A.

    2007-12-01

    A large decline in beech populations ( Fagus grandifolia) has been well-documented from pollen records in southeastern Michigan and Southern Ontario between 1000 and 600 BP. These records reveal that declines in beech pollen were generally associated with increases in oak ( Quercus) and pine ( Pinus). The beech decline probably extended eastward into western Pennsylvania and New York, although beech populations in Upper Michigan remained unaffected or even expanded during this time period. The causes of these forest changes and their spatial patterning is not completely understood, although they have been variously attributed to anthropogenic disturbance, climatic cooling, or drought. Recent paleoclimate evidence from the region indicates that the most severe droughts of the last 2000 years occurred between 1000 and 700 BP. However, direct attribution of drought as a cause of the decline has been problematic because of uncertainties associated with comparison of radiocarbon-dated chronologies. We have conducted tandem investigations of pollen, charcoal, hydroclimate proxies (testate amoebae, humification), and a temperature proxy (d18O of Sphagnum cellulose) from the archives contained in three Sphagnum-dominated peatlands of the region. Two of these peatlands were located within the region of the beech decline (eastern, lower Michigan) and the other was outside the decline region (Upper Michigan). Our results reveal that a series of large droughts, likely the combined result of decreased summer precipitation and warm temperatures, were associated with the beech decline. Large wildfires were also associated with the droughts. Neither droughts nor beech declines were recorded in Upper Michigan. High-resolution analysis of beech pollen and hydroclimate proxies at sites that experienced the droughts reveals complex dynamics at multidecadal timescales between 1000-700 BP, with large fluctuations in beech pollen, available moisture, and charcoal concentrations. Our

  16. Climate change and the increasing impact of polar bears on bird populations

    Directory of Open Access Journals (Sweden)

    Jouke eProp

    2015-03-01

    Full Text Available The Arctic is becoming warmer at a high rate, and contractions in the extent of sea ice are currently changing the habitats of marine top-predators dependent on ice. Polar bears (Ursus maritimus depend on sea ice for hunting seals. For these top-predators, longer ice-free seasons are hypothesized to force the bears to hunt for alternative terrestrial food, such as eggs from colonial breeding birds. We analyzed time-series of polar bear observations at four locations on Spitsbergen (Svalbard and one in east Greenland. Summer occurrence of polar bears, measured as the probability of encountering bears and the number of days with bear presence, has increased significantly from the 1970/80s to the present. The shifts in polar bear occurrence coincided with trends for shorter sea ice seasons and less sea ice during the spring in the study area. This resulted in a strong inverse relationship between the probability of bear encounters on land and the length of the sea ice season. Within ten years after their first appearance on land, polar bears had advanced their arrival dates by almost 30 days. Direct observations of nest predation showed that polar bears may severely affect reproductive success of the barnacle goose (Branta leucopsis, common eider (Somateria mollissima and glaucous gull (Larus hyperboreus. Nest predation was strongest in years when the polar bears arrived well before hatch, with more than 90% of all nests being predated. The results are similar to findings from Canada, and large-scale processes, such as climate and subsequent habitat changes, are pinpointed as the most likely drivers in various parts of the Arctic. We suggest that the increasing, earlier appearance of bears on land in summer reflects behavioral adaptations by a small segment of the population to cope with a reduced hunting range on sea ice. This exemplifies how behavioral adaptations may contribute to the cascading effects of climate change.

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

    DEFF Research Database (Denmark)

    Meyrowitsch, Dan Wolf; Pedersen, Erling Møller; Alifrangis, Michael

    2011-01-01

    ABSTRACT: 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 was used to analyze the association between monthly rainfall and malaria mosquito populations. RESULTS: The average number...

  18. Factors affecting population dynamics of leaf beetles in a subarctic region: The interplay between climate warming and pollution decline.

    Science.gov (United States)

    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.

  19. Effects of land use on bird populations and pest control services on coffee farms.

    Science.gov (United States)

    Railsback, Steven F; Johnson, Matthew D

    2014-04-22

    Global increases in both agriculture and biodiversity awareness raise a key question: Should cropland and biodiversity habitat be separated, or integrated in mixed land uses? Ecosystem services by wildlife make this question more complex. For example, birds benefit agriculture by preying on pest insects, but other habitat is needed to maintain the birds. Resulting land use questions include what areas and arrangements of habitat support sufficient birds to control pests, whether this pest control offsets the reduced cropland, and the comparative benefits of "land sharing" (i.e., mixed cropland and habitat) vs. "land sparing" (i.e., separate areas of intensive agriculture and habitat). Such questions are difficult to answer using field studies alone, so we use a simulation model of Jamaican coffee farms, where songbirds suppress the coffee berry borer (CBB). Simulated birds select habitat and prey in five habitat types: intact forest, trees (including forest fragments), shade coffee, sun coffee, and unsuitable habitat. The trees habitat type appears to be especially important, providing efficient foraging and roosting sites near coffee plots. Small areas of trees (but not forest alone) could support a sufficient number of birds to suppress CBB in sun coffee; the degree to which trees are dispersed within coffee had little effect. In simulations without trees, shade coffee supported sufficient birds to offset its lower yield. High areas of both trees and shade coffee reduced pest control because CBB was less often profitable prey. Because of the pest control service provided by birds, land sharing was predicted to be more beneficial than land sparing in this system.

  20. Effects of land use on bird populations and pest control services on coffee farms

    Science.gov (United States)

    Railsback, Steven F.; Johnson, Matthew D.

    2014-01-01

    Global increases in both agriculture and biodiversity awareness raise a key question: Should cropland and biodiversity habitat be separated, or integrated in mixed land uses? Ecosystem services by wildlife make this question more complex. For example, birds benefit agriculture by preying on pest insects, but other habitat is needed to maintain the birds. Resulting land use questions include what areas and arrangements of habitat support sufficient birds to control pests, whether this pest control offsets the reduced cropland, and the comparative benefits of “land sharing” (i.e., mixed cropland and habitat) vs. “land sparing” (i.e., separate areas of intensive agriculture and habitat). Such questions are difficult to answer using field studies alone, so we use a simulation model of Jamaican coffee farms, where songbirds suppress the coffee berry borer (CBB). Simulated birds select habitat and prey in five habitat types: intact forest, trees (including forest fragments), shade coffee, sun coffee, and unsuitable habitat. The trees habitat type appears to be especially important, providing efficient foraging and roosting sites near coffee plots. Small areas of trees (but not forest alone) could support a sufficient number of birds to suppress CBB in sun coffee; the degree to which trees are dispersed within coffee had little effect. In simulations without trees, shade coffee supported sufficient birds to offset its lower yield. High areas of both trees and shade coffee reduced pest control because CBB was less often profitable prey. Because of the pest control service provided by birds, land sharing was predicted to be more beneficial than land sparing in this system. PMID:24711377

  1. Winter density and habitat preferences of three declining granivorous farmland birds: The importance of the keeping of poultry and dairy farms

    Czech Academy of Sciences Publication Activity Database

    Šálek, Martin; Havlíček, J.; Riegert, J.; Nešpor, M.; Fuchs, R.; Kipson, M.

    2015-01-01

    Roč. 24, č. 1 (2015), s. 10-16 ISSN 1617-1381 Institutional support: RVO:68081766 Keywords : Central Europe * Dairy farms * Granivorous birds * Habitat preferences * Poultry keeping * Winter period Subject RIV: EH - Ecology, Behaviour Impact factor: 2.220, year: 2015

  2. Can we successfully monitor a population density decline of elusive invertebrates? A statistical power analysis on Lucanus cervus

    Directory of Open Access Journals (Sweden)

    Arno Thomaes

    2017-07-01

    Full Text Available Monitoring global biodiversity is essential for understanding and countering its current loss. However, monitoring of many species is hindered by their difficult detection due to crepuscular activity, hidden phases of the life cycle, short activity period and low population density. Few statistical power analyses of declining trends have been published for terrestrial invertebrates. Consequently, no knowledge exists of the success rate of monitoring elusive invertebrates. Here data from monitoring transects of the European stag beetle, Lucanus cervus, is used to investigate whether the population trend of this elusive species can be adequately monitored. Data from studies in UK, Switzerland and Germany were compiled to parameterize a simulation model explaining the stag beetle abundance as a function of temperature and seasonality. A Monte-Carlo simulation was used to evaluate the effort needed to detect a population abundance decline of 1%/year over a period of 12 years. To reveal such a decline, at least 240 1-hour transect walks on 40 to 100 transects need to be implemented in weekly intervals during warm evenings. It is concluded that monitoring of stag beetles is feasible and the effort is not greater than that which has been found for other invertebrates. Based on this example, it is assumed that many other elusive species with similar life history traits can be monitored with moderate efforts. As saproxylic invertebrates account for a large share of the forest biodiversity, although many are elusive, it is proposed that at least some flagship species are included in monitoring programmes.

  3. Quantitative assessment of the importance of phenotypic plasticity in adaptation to climate change in wild bird populations.

    Directory of Open Access Journals (Sweden)

    Oscar Vedder

    2013-07-01

    Full Text Available Predictions about the fate of species or populations under climate change scenarios typically neglect adaptive evolution and phenotypic plasticity, the two major mechanisms by which organisms can adapt to changing local conditions. As a consequence, we have little understanding of the scope for organisms to track changing environments by in situ adaptation. Here, we use a detailed individual-specific long-term population study of great tits (Parus major breeding in Wytham Woods, Oxford, UK to parameterise a mechanistic model and thus directly estimate the rate of environmental change to which in situ adaptation is possible. Using the effect of changes in early spring temperature on temporal synchrony between birds and a critical food resource, we focus in particular on the contribution of phenotypic plasticity to population persistence. Despite using conservative estimates for evolutionary and reproductive potential, our results suggest little risk of population extinction under projected local temperature change; however, this conclusion relies heavily on the extent to which phenotypic plasticity tracks the changing environment. Extrapolating the model to a broad range of life histories in birds suggests that the importance of phenotypic plasticity for adjustment to projected rates of temperature change increases with slower life histories, owing to lower evolutionary potential. Understanding the determinants and constraints on phenotypic plasticity in natural populations is thus crucial for characterising the risks that rapidly changing environments pose for the persistence of such populations.

  4. Pesticides Are Involved With Population Declines of Amphibians in the California Sierra Nevadas

    Directory of Open Access Journals (Sweden)

    Donald W. Sparling

    2001-01-01

    Full Text Available 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 [1,2]. Several factors including introduced predators [3,4,5], habitat loss [2], and ultraviolet radiation [6] 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 Sierras [7,8].

  5. Amphibian populations in the terrestrial environment: Is there evidence of declines of terrestrial forest amphibians in northwestern California?

    Science.gov (United States)

    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.

  6. Declining brown-headed cowbird (Molothrus ater) populations are associated with landscape-specific reductions in brood parasitism and increases in songbird productivity

    Science.gov (United States)

    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...

  7. Two-year decline in vision but not hearing is associated with memory decline in very old adults in a population-based sample.

    Science.gov (United States)

    Anstey, K J; Luszcz, M A; Sanchez, L

    2001-01-01

    Recent cross-sectional research in cognitive aging has demonstrated a robust association between visual acuity, auditory thresholds and cognitive performance in old age. However, the nature of the association is still unclear, particularly with respect to whether sensory and cognitive function are causally related. This study aimed to determine whether marked declines in performance on screening measures of either visual acuity or auditory thresholds have an effect on cognitive decline over 2 years. The sample from the Australian Longitudinal Study of Ageing (n = 2,087) were assessed in 1992 and 1994 on measures of sensory and cognitive function as part of a larger clinical assessment. A quasi-experimental design involving comparison of extreme groups using repeated measures MANCOVA with age as a covariate was used. Group performance on measures of hearing, memory, verbal ability and processing speed declined significantly. Decline in visual acuity had a significant effect on memory decline, but not on decline in verbal ability or processing speed. Decline in hearing was not associated with decline in any cognitive domain. The common association between visual acuity, auditory thresholds and cognitive function observed in cross-sectional studies appears to be disassociated in longitudinal studies. Copyright 2001 S. Karger AG, Basel

  8. HUMIDIFICATION AS A FACTOR OF STRUCTURIAL ORGANIZATION OF BIRD POPULATIONS IN THE WOOD STANDS OF THE BIOSPHERE RESERVE ASKANIA NOVA

    Directory of Open Access Journals (Sweden)

    Listopadsky M. A.

    2014-04-01

    Full Text Available The influence of different humidification types towards appearance of forest vegetation conditions on spatial organization of birds in the wood stands is analyzed. Population density, coefficient of occurrence, and informative connection with six types of soil humidification are given for 53 bird species. The informative estimation of every humidification type is determined for every bird species. Thereby it is definitely a contribution of every gradation of edaphic factor to the structural genesis of dendrophilous bird communities. The strongest informative connection between humidity gradients and the avifauna structure of the wood stands is available in dry edaphotopes for margin representatives and fresh one for typical forest species. These two humidification types play a start function in the structural genesis of some blocks of dendrophilous bird communities per se. It is determined that change of bird species of forest-steppe faunogenetic complex by species from Nemoral complex undergoes in most cases on the border of the gradient between fresh and humid edaphotopes. For 53 species of birds from dendrophilous complex is was revealed that the importance of different levels of soil moisture has a different impact in shaping of the modern structure dendrophilous avifauna. Dry and especially drily edaphotopes determine the spatial structure of the species that are of forest-steppe origin and belong to the representatives of the optional component of dendrophilous bird communities. Wet edafotopes are involved in the formation of the spatial structure of species of predominantly immoral origin and relate to the obligate component of representatives of dendrophilous bitd comminities. Gradient wetting of edaphotopes on the verge of ‘linked’/’fresh’ is restructuring for the bird communities. It takes an optional replacement red communists feature to obligate. Stands rather dry and fresh items currently being the most active formation of

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

    Science.gov (United States)

    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.

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

    KAUST Repository

    Vignaud, Thomas M.

    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.

  11. A global threats overview for Numeniini populations: synthesising expert knowledge for a group of declining migratory birds

    NARCIS (Netherlands)

    Pearce-Higgins, J.W.; Brown, D.J.; Douglas, D.J.T.; Alves, J.A.; Bellio, M.; Bocher, P.; Buchanan, G.M.; Clay, R.P.; Conklin, J.; Crockford, N.; Dann, P.; Elts, J.; Friis, C.; Fuller, R.A.; Gill, J.A.; Gosbell, K.; Johnson, J.A.; Marquez-Ferrando, R.; Masero, J.A.; Merlville, D.S.; Millington, S.; Minton, C.; Mundkur, T.; Nol, E.; Pehlak, H.; Piersma, T.; Robin, F.; Rogers, D.I.; Ruthrauff, D.R.; Senner, N.R.; Shah, J.N.; Sheldon, R.D.; Soloviev, S.A.; Tomkovich, P.S.; Verkuil, Y.I.

    2017-01-01

    The Numeniini is a tribe of 13 wader species (Scolopacidae, Charadriiformes) of which seven are Near Threatened or globally threatened, including two Critically Endangered. To help inform conservation management and policy responses, we present the results of an expert assessment of the threats that

  12. A global threats overview for Numeniini populations : Synthesising expert knowledge for a group of declining migratory birds

    NARCIS (Netherlands)

    Pearce-Higgins, James W.; Brown, Daniel J.; Douglas, David J. T.; Alves, Jose A.; Bellio, Mariagrazia; Bocher, Pierrick; Buchanan, Graeme M.; Clay, Rob P.; Conklin, Jesse; Crockford, Nicola J.; Dann, Peter; Elts, Jaanus; Friis, Christian; Fuller, Richard A.; Gill, Jennifer A.; Gosbell, Ken; Johnson, James A.; Márquez-Ferrando, Rocío; Masero, Jose A.; Melville, David S.; Millington, Spike; Minton, Clive D. T.; Mundkur, Taej; Nol, Erica; Pehlak, Hannes; Piersma, Theunis; Robin, Frederic; Rogers, Danny I.; Ruthrauff, Daniel R.; Senner, Nathan R.; Shah, Junid N.; Sheldon, Rob D.; Soloviev, Sergej A.; Tomkovich, Pavel S.; Verkuil, Yvonne I.

    2017-01-01

    The Numeniini is a tribe of 13 wader species (Scolopacidae, Charadriiformes) of which seven are Near Threatened or globally threatened, including two Critically Endangered. To help inform conservation management and policy responses, we present the results of an expert assessment of the threats that

  13. STRUCTURE AND SPATIOTEMPORAL HETEROGENEITY OF BIRD SUMMER POPULATION IN DAGESTAN HIGH MOUNTAINS (BY EXAMPLE OF CHARODINSKY DISTRICT

    Directory of Open Access Journals (Sweden)

    Ye. V. Vilkov

    2013-01-01

    Full Text Available The paper deals with the study of a structure and formation peculiarities of spatial connections of birds in two different biotopic natural complexes in one of Dagestan high mountain districts – Charodinsky (at the altitude interval of 2000-2300 m. Biotopic heterogeneity of the ornithological population has made it possible to single out and give an elaborate description of 10 differentiated ornithological complexes which represent the actual correlation between background landscape types. It has been established that the avifauna structure in Dagestan high-mountain areas includes 8 fauna-genetic groups of birds making local ecological micro-pulations as members of widely spread species typical of lowlands, mountain fauna and Caucasian endemics. We suggest that local population of migrating birds in high mountains is formed of local (high-mountain ecologically adapted micropopulations and as well replenished by their own offspring. At present the structure of the high-mountain avifauna may undergo certain changes owing to global warming and ever rising anthropogenic load accompanied by destruction of natural landscapes.

  14. Ginkgo Biloba Extract and Long-Term Cognitive Decline: A 20-Year Follow-Up Population-Based Study

    Science.gov (United States)

    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

  15. Ginkgo biloba extract and long-term cognitive decline: a 20-year follow-up population-based study.

    Directory of Open Access Journals (Sweden)

    Hélène Amieva

    Full Text Available 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.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.Cognitive decline in a non-demented elderly population was lower in subjects who reported using EGb761® than in those who did not. This effect may be a specific medication

  16. Ecosystem scale declines in elk recruitment and population growth with wolf colonization: a before-after-control-impact approach.

    Directory of Open Access Journals (Sweden)

    David Christianson

    Full Text Available 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.

  17. Adherence to a Mediterranean-type dietary pattern and cognitive decline in a community population123

    Science.gov (United States)

    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

  18. Catastrophic Decline of World's Largest Primate: 80% Loss of Grauer's Gorilla (Gorilla beringei graueri) Population Justifies Critically Endangered Status

    Science.gov (United States)

    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

  19. Climate Warming as a Possible Trigger of Keystone Mussel Population Decline in Oligotrophic Rivers at the Continental Scale.

    Science.gov (United States)

    Bolotov, Ivan N; Makhrov, Alexander A; Gofarov, Mikhail Yu; Aksenova, Olga V; Aspholm, Paul E; Bespalaya, Yulia V; Kabakov, Mikhail B; Kolosova, Yulia S; Kondakov, Alexander V; Ofenböck, Thomas; Ostrovsky, Andrew N; Popov, Igor Yu; von Proschwitz, Ted; Rudzīte, Mudīte; Rudzītis, Māris; Sokolova, Svetlana E; Valovirta, Ilmari; Vikhrev, Ilya V; Vinarski, Maxim V; Zotin, Alexey A

    2018-01-08

    The effects of climate change on oligotrophic rivers and their communities are almost unknown, albeit these ecosystems are the primary habitat of the critically endangered freshwater pearl mussel and its host fishes, salmonids. The distribution and abundance of pearl mussels have drastically decreased throughout Europe over the last century, particularly within the southern part of the range, but causes of this wide-scale extinction process are unclear. Here we estimate the effects of climate change on pearl mussels based on historical and recent samples from 50 rivers and 6 countries across Europe. We found that the shell convexity may be considered an indicator of the thermal effects on pearl mussel populations under warming climate because it reflects shifts in summer temperatures and is significantly different in viable and declining populations. Spatial and temporal modeling of the relationship between shell convexity and population status show that global climate change could have accelerated the population decline of pearl mussels over the last 100 years through rapidly decreasing suitable distribution areas. Simulation predicts future warming-induced range reduction, particularly in southern regions. These results highlight the importance of large-scale studies of keystone species, which can underscore the hidden effects of climate warming on freshwater ecosystems.

  20. Adaptive landscapes and density-dependent selection in declining salmonid populations: going beyond numerical responses to human disturbance.

    Science.gov (United States)

    Einum, Sigurd; Robertsen, Grethe; Fleming, Ian A

    2008-05-01

    Theory suggests an important role for population density in shaping adaptive landscapes through density-dependent selection. Here, we identify five methodological approaches for studying such selection, review the existing empirical evidence for it, and ask whether current declines in abundance can be expected to trigger evolutionary responses in salmonid fishes. Across taxa we find substantial amounts of evidence for population density influencing the location of adaptive peaks for a range of traits, and, in the presence of frequency dependence, changing the shape of selection (stabilizing versus disruptive). For salmonids, biological and theoretical considerations suggest that the optimal value of a number of traits associated with juvenile competitive ability (e.g. egg size, timing of emergence from nests, dominance ability), may depend on population density. For adults, more direct experimental and comparative evidence suggest that secondary sexual traits can be subject to density-dependent selection. There is also evidence that density affects the frequency-dependent selection likely responsible for the expression of alternative male reproductive phenotypes in salmon. Less is known however about the role of density in maintaining genetic variation among juveniles. Further efforts are required to elucidate the indirect evolutionary effects of declining population abundances, both in salmonids and in other anthropogenically challenged organisms.

  1. Declining human population but increasing residential development around protected areas in Puerto Rico

    Science.gov (United States)

    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...

  2. The long-term effect of the timing of fertility decline on population size

    NARCIS (Netherlands)

    O'Neill, BC; Scherbov, S; Lutz, W

    1999-01-01

    Existing long-range population projections imply that the timing of the fertility transition has a relatively unimportant effect on long-term population size when compared with the impact of the level at which fertility is assumed eventually to stabilize. However, this note shows that the effect of

  3. Prevalence of Taxa of Pasteurellaceae Among Populations of Healthy Captive Psittacine Birds

    DEFF Research Database (Denmark)

    Bisgaard, M.; Xin, Di; Bertelsen, M. F.

    2017-01-01

    Sixty-two strains of Pasteurellaceae-like bacteria were isolated from the tracheas of 87 clinically healthy psittacine birds in two Danish zoos. The isolates were identified by a combination of rpoB and 16S rRNA gene sequencing and by matrix-assisted laser desorption–ionization time of flight. Tw...

  4. MULTIDRUG RESISTANCE IN WILD BIRD POPULATIONS: IMPORTANCE OF THE FOOD CHAIN.

    Science.gov (United States)

    Pinto, Andreia; Simões, Romeo; Oliveira, Manuela; Vaz-Pires, Paulo; Brandão, Ricardo; da Costa, Paulo Martins

    2015-12-01

    The presence of multidrug-resistant (MDR) Escherichia coli has recently been reported in wild birds (gulls and birds of prey) that had no apparent exposure to antimicrobials. Little work has been done to assess the role of the food chain in the emergence and spread of MDR E. coli . In this study, we evaluated the presence of MDR E. coli in 29 fecal samples collected from wild birds living in a rehabilitation center (the center receives injured animals found in their natural habitat) and in eight feed samples. In total, 166 E. coli isolates were obtained: 129 from cloacal swabs and 37 from raw feed samples. The antimicrobial resistance profile of these isolates was determined, and we found that 75 isolates showed resistance to five or more drugs, resulting in a total of 38 different antimicrobial resistance patterns. Subsequently, the molecular characterization of 36 isolates, performed by pulsed-field gel electrophoresis, revealed a great similarity between isolates collected from various species of birds and also between these last ones and the ones found in their feed samples.

  5. Individual variation in rates of senescence : natal origin effects and disposable soma in a wild bird population

    NARCIS (Netherlands)

    Bouwhuis, Sandra; Charmantier, Anne; Verhulst, Simon; Sheldon, Ben C.; Sandercock, Brett

    2010-01-01

    P>1. Longitudinal studies of various vertebrate populations have recently demonstrated senescent declines in reproductive performance and/or survival probability with age to be almost ubiquitous in nature. Little is known, however, about the extent to which rates of senescence vary between

  6. Monitoring the impact of the Gordon C. Leitch oil spill on the breeding bird populations of the Mingan Archipelago National Park Reserve, (QC) Canada

    International Nuclear Information System (INIS)

    Roberge, B.; Chapdelaine, G.

    2000-01-01

    Results of a monitoring study of the impact of a 1999 oil spill on the breeding bird population in the Mingan Archipelago National Park Reserve in the Gulf of St. Lawrence, Quebec, are discussed. The common eider, the black guillemot and the bald eagle were the three species studied by observing and comparing the status of these bird populations on islands located inside and outside of the contaminated area. Data from before and after the oil spill were compared. Results show that an estimated 211 to 777 breeding birds have died as a result of the oil spill, however, the overall impact on the reproductive potential of the breeding bird population was insignificant. Various protective measures to mitigate the effects of future oil spills are proposed. 38 refs., 7 tabs., 1 fig

  7. Browsing Patterns of White-Tailed Deer Following Increased Timber Harvest and a Decline in Population Density

    Directory of Open Access Journals (Sweden)

    Shawn M. Crimmins

    2010-01-01

    Full Text Available We examined browsing patterns of white-tailed deer (Odocoileus virginianus on a site in the central Appalachians that experienced a substantial (>50% reduction in deer population density and an increase in the amount of timber harvest since 2001. We sampled woody browse in and immediately adjacent to 12 clearcuts ranging in age from 0–5 years postharvest in summer 2007. Clearcut-interior areas had higher woody browse abundance and browsing rates than clearcut-edge or mature forest areas. Woody browse abundance was slightly higher within individual clearcuts than in 2001 at higher population densities and lower timber harvest rates. Overall browsing rates declined from approximately 17% in 2001 to less than 5% during our study, suggesting that the combination of deer population control, and increasing the amount of timber harvest across the landscape can reduce herbivory to levels that may not impede growth and survival of forest vegetation.

  8. Effect of air and noise pollution on species diversity and population density of forest birds at Lalpahari, West Bengal, India.

    Science.gov (United States)

    Saha, Dulal C; Padhy, Pratap K

    2011-11-15

    The Rajmahal-type quality stones for building purposes are found abundantly in Birbhum district, West Bengal, India, where stone mining and crushing have become the main industrial activity. Although crusher dust is injurious to health, demand for crushed stone is ever-increasing as a result of rapid infrastructural growth in the country. Most of the crusher units at Rampurhat are situated along the roadways adjacent to forest under Tumboni Beat of Rampurhat Range of Birbhum Forest Division. Excessive load of air pollution in this area has led to degradation of this forest. The status of the ambient air and noise level was evaluated. The effect of air and noise pollution on abundance and variability of birds in this forest have been compared to an almost non-polluted forest of the same bio-geographic zone. Both species diversity and population density of birds were found to decrease in the polluted forest, especially in the areas adjacent to crushers. For comparing the pollution status of two different forest sites and for establishing whether the density of birds have any correlation between the sites, the Student's t-test and the chi-square test were applied respectively. Most of the results proved to be significant. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Modeling the growth and decline of pathogen effective population size provides insight into epidemic dynamics and drivers of antimicrobial resistance.

    Science.gov (United States)

    Volz, Erik M; Didelot, Xavier

    2018-02-07

    Non-parametric population genetic modeling provides a simple and flexible approach for studying demographic history and epidemic dynamics using pathogen sequence data. Existing Bayesian approaches are premised on stochastic processes with stationary increments which may provide an unrealistic prior for epidemic histories which feature extended period of exponential growth or decline. We show that non-parametric models defined in terms of the growth rate of the effective population size can provide a more realistic prior for epidemic history. We propose a non-parametric autoregressive model on the growth rate as a prior for effective population size, which corresponds to the dynamics expected under many epidemic situations. We demonstrate the use of this model within a Bayesian phylodynamic inference framework. Our method correctly reconstructs trends of epidemic growth and decline from pathogen genealogies even when genealogical data is sparse and conventional skyline estimators erroneously predict stable population size. We also propose a regression approach for relating growth rates of pathogen effective population size and time-varying variables that may impact the replicative fitness of a pathogen. The model is applied to real data from rabies virus and Staphylococcus aureus epidemics. We find a close correspondence between the estimated growth rates of a lineage of methicillin-resistant S. aureus and population-level prescription rates of β-lactam antibiotics. The new models are implemented in an open source R package called skygrowth which is available at https://github.com/mrc-ide/skygrowth. © The Author(s) 2018. Published by Oxford University Press, on behalf of the Society of Systematic Biologists.

  10. Abundance of invertebrate prey for birds on organic and conventional arable farms in the Netherlands

    NARCIS (Netherlands)

    Kragten, S.; Tamis, W.L.M.; Gentenaar, E.; Midcap Ramiro, S.M.; Poll, van der R.J.; Wang, J.; Snoo, de G.R.

    2011-01-01

    As a result of agricultural intensification, populations of farmland birds have been in steep decline for several decades. Reduction in food abundance has been mentioned as one factor behind these declines. Extensive farm management, such as use of organic methods, is expected to provide more food

  11. An evaluation of marine bird population trends following the Exxon Valdez oil spill, Prince William Sound, Alaska

    International Nuclear Information System (INIS)

    Lance, Brian K.; Irons, David B.; Kendall, Steven J.; McDonald, Lyman L.

    2001-01-01

    We examined post-spill trends (1989-1998) of marine bird populations in Prince William Sound (PWS) following the Exxon Valdez oil spill (EVOS) to evaluate recovery of injured taxa. Two criteria were employed. First, we examined population trends of injured taxa only in the oiled area of PWS using regression models. Second, we examined population trends of injured taxa in the oiled area relative to the unoiled area using homogeneity of the slopes tests. We considered a population recovering if there was a positive trend using either criteria. We considered a population not recovering if there was no trend using either criteria or a negative trend in the oiled area. A significant negative trend in the oiled area relative to the unoiled area was considered a continuing and increasing effect. Most taxa for which injury was previously demonstrated were not recovering and some taxa showed evidence of increasing effects nine years after the oil spill. Four taxa (loons Gavia spp, Harlequin Duck Histrionicus histrionicus, Bufflehead Bucephala spp, and North-western Crow Corvus caurinus) showed weak to very weak evidence of recovery. None of these taxa showed positive trends in both winter and summer. Nine taxa (grebes Podiceps spp, cormorants Phalacrocorax spp, Black Oystercatcher Haematopus bachmani, Mew Gull Larus canus, Glaucous-winged Gull Larus glaucescens, terns Sterna spp, murres Uria spp, Pigeon Guillemot Cepphus columba, and murrelets Brachyramphus spp) showed no evidence of recovery during summer or winter. Four taxa (scoters Melanitta spp, mergansers Mergus spp, goldeneyes Bucephala spp, and Black-legged Kittiwake Rissa tridactyla) showed evidence of continuing, increasing effects. We showed evidence of slow recovery, lack of recovery, and divergent population trends in many taxa which utilise shoreline and nearshore habitats where oil is likely to persist. Potential lingering spill effects and natural variability appear to be acting in concert in delaying

  12. Interpreting population estimates of birds following pesticide applications--behavior of male starlings exposed to an organophosphate pesticide

    Science.gov (United States)

    Grue, C.E.; Shipley, B.J.; Ralph, C. John; Scott, J. Michael

    1981-01-01

    We determined activity budgets for 10 pairs of captive male Starlings between 7 May and 18 July 1980. Our objective was to quantify changes in behavior after exposure to an organophosphate (OP) pesticide and to assess the impact of changes in behavior on the interpretation of population estimates of birds following pesticide applications. We observed each pair of males for an hour at 07:30 and 09:30 for four days and classified their behavior into one of four categories: flying, perching, foraging, or singing and displaying. At 06:30 on day 2, one male received a single oral dose of 2.5 mg dicrotophos (3-hydroxy-N, N-dimethyl-cis-crotonamide dimethyl phosphate) per kg of body weight; the other male received an equivalent exposure of corn oil. Changes in the activity budgets of OP-dosed and control males were compared using t-tests. Activity of OP-dosed males was significantly (P _ 0.05) reduced within the 2-4 h following exposure. OP-dosed males spent more time perching (46.1%) than controls and less time flying (-96.6%), foraging (-28.5%), and singing and displaying (-49.5%). The frequency of perching (-75.3%), flying (-83.8%), foraging (-54.1%), and singing and displaying (- 59.2%) was significantly reduced. Activity in OP-dosed males returned to normal by 26-28 h posttreatment. Results suggest that movement and vocalization may be significantly reduced in birds exposed to organophosphate and carbamate pesticides. Conventional censusing techniques and population estimating procedures may, therefore, be inadequate to assess changes in bird populations after pesticide applications because of the difficulty in separating decreases in density due to mortality or emigration from reductions in activity.

  13. Effects of Width, Edge and Habitat on the Abundance and Nesting Success of Scrub-shrub Birds in Powerline Corridors

    Science.gov (United States)

    David I. King; Richard B. Chandler; Jeffrey M. Collins; Wayne R. Petersen; Thomas E. Lautzenheiser

    2009-01-01

    Concern about declines in scrub–shrub bird populations has resulted in efforts to create and maintain habitat for these species. Vegetation within powerline corridors is managed to prevent contact of vegetation with transmission lines, and comprises approximately 2% of all of habitat for scrub–shrub birds in southern New England. Although previous studies have...

  14. Joint review of related contracts on bird populations in the Ravenglass Estuary

    International Nuclear Information System (INIS)

    Anderson, N.; Evans, P.R.; Lowe, V.P.W.

    1987-10-01

    Black-headed Gulls breeding at Ravenglass (and at other coastal sites in Cumbria) fed exclusively inland during the breeding season and so they and their young could not have acquired any radionuclides present in the estuarine muds and invertebrates. Levels in the invertebrates and in gull tissues were low; they were slightly higher in Shelducks, which feed on estuarine invertebrates but have nested successfully at Ravenglass in recent years. Gulls and two other ground-nesting bird species have suffered severe disturbance and predation by foxes in recent springs at Ravenglass; Shelducks nest in burrows and have escaped such effects. Levels of radionuclides in birds, particularly gulls, are too low to have caused breeding failures at Ravenglass. (author)

  15. Diclofenac disposition in Indian cow and goat with reference to Gyps vulture population declines

    International Nuclear Information System (INIS)

    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.

    2007-01-01

    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 μg 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. - Residual diclofenac in livestock carcasses in India poses a continuing risk to Gyps vultures

  16. Diclofenac disposition in Indian cow and goat with reference to Gyps vulture population declines

    Energy Technology Data Exchange (ETDEWEB)

    Taggart, M.A. [Royal Society for the Protection of Birds, The Lodge, Sandy, Bedfordshire, SG19 2DL (United Kingdom); School of Biological Sciences, Department of Plant and Soil Science, University of Aberdeen, AB24 3UU (United Kingdom); Cuthbert, R. [Royal Society for the Protection of Birds, The Lodge, Sandy, Bedfordshire, SG19 2DL (United Kingdom)]. E-mail: richard.cuthbert@rspb.org.uk; Das, D. [Bombay Natural History Society, Hornbill House, Mumbai, 400023 (India); Sashikumar, C. [Bombay Natural History Society, Hornbill House, Mumbai, 400023 (India); Pain, D.J. [Royal Society for the Protection of Birds, The Lodge, Sandy, Bedfordshire, SG19 2DL (United Kingdom); Green, R.E. [Royal Society for the Protection of Birds, The Lodge, Sandy, Bedfordshire, SG19 2DL (United Kingdom); Conservation Biology Group, Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ (United Kingdom); Feltrer, Y. [Institute of Zoology, Zoological Society of London, Regent' s Park, London, NW1 4RY (United Kingdom); Shultz, S. [Royal Society for the Protection of Birds, The Lodge, Sandy, Bedfordshire, SG19 2DL (United Kingdom); Institute of Zoology, Zoological Society of London, Regent' s Park, London, NW1 4RY (United Kingdom); Cunningham, A.A. [Institute of Zoology, Zoological Society of London, Regent' s Park, London, NW1 4RY (United Kingdom); Meharg, A.A. [School of Biological Sciences, Department of Plant and Soil Science, University of Aberdeen, AB24 3UU (United Kingdom)

    2007-05-15

    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 {mu}g kg{sup -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. - Residual diclofenac in livestock carcasses in India poses a continuing risk to Gyps vultures.

  17. The decline of the Nile crocodile population in Loskop Dam, Olifants ...

    African Journals Online (AJOL)

    2010-05-18

    May 18, 2010 ... 2 Mpumalanga Tourism and Parks Agency, Scientific Services, PO Box 1250, Groblersdal, 0470, South Africa. 3 Department of Biology, ..... Gland, Switzerland. GRAHAM A (1968) The Lake Rudolf crocodile (Crocodylus niloti cus Laurenti) population. Unpublished Report, Kenya Game. Department, Nairobi.

  18. Declines in populations of Salix caprea L.during forest regeneration after strong herbivore pressure

    Directory of Open Access Journals (Sweden)

    Janusz B. Faliński

    2014-01-01

    Full Text Available Communities of broadleaved forest subject to strong pressure from large herbivores underwent degeneration. The relief of this pressure led to regeneration of the community, in which an important role was played by the sallow Salix caprea and other light-seeded pioneer species of tree (Populus tremula, Betula pendula and B. pubescens. Regeneration involving Salix caprea proceeded following the conservatorial protection of the degenerate stands in a reserve and later in Białowieża National Park. The emergence and development of the population of Salix caprea proceeded following the invasion of spruce, which coincided with the period of enhanced animal pressure on broadleaved forest. Salix caprea filled all the gaps in the tree stand arising as a result of the destruction of trees and undergrowth by herbivores (in the years 1892-1915. It also appeared en masse on old, at that time unforested, clearings and felled areas. In these places, Salix caprea created very abundant populations, with particular trees being in good condition, with a habit typical of forest trees and attaining considerable heights. The majority of trees were 50-60 years old at the time of death, although individuals reached 74 years of age. The process of extinction of the sallow population - observed over 19 years on permanent plots and fixed trees - proceeded very quickly, especially in the first decade of observation. It led to the almost complete disappearance of sallow for the forest communities of Białowieża National Park. The death of individual trees is preceded by impairment of their health and reduced annual increments in the 4-9 last years of life. The extinction of the population is associated with the loss of its primary phenological differentiation and with a change in the sex structure of the population from a prevalence of female trees to a near even distribution of the two sexes. The development of the populations of permanent constituents of the forest

  19. Mathematical model for bird flu disease transmission with no bird ...

    African Journals Online (AJOL)

    In this paper a mathematical model for the transmission dynamics of bird flu among birds and humans is presented. The model assumes that there is no migration of birds in the susceptible bird population immediately the disease starts. The model formulated is analyzed using dynamical systems theory . The analysis of the ...

  20. mathematical model for bird flu disease transmission with no bird ...

    African Journals Online (AJOL)

    Admin

    In this paper a mathematical model for the transmission dynamics of bird flu among birds and humans is presented. The model assumes that there is no migration of birds in the susceptible bird population immediately the disease starts. The model formulated is analyzed using dynamical systems theory. The analysis of the ...

  1. The ongoing decline of the breeding population of Black-tailed Godwits Limosa l. limosa in The Netherlands is not explained by changes in adult survival

    NARCIS (Netherlands)

    Roodbergen, Maja; Klok, Chris; Schekkerman, Hans

    2008-01-01

    The Black-tailed Godwit Limosa limosa is a characteristic breeding wader of wet grasslands in The Netherlands which has suffered a strong population decline since the 1960s. Low breeding success has been implicated as the main driver of this decline and here we examine whether changes in adult

  2. The ongoing decline of the breeding population of Black-tailed Godwits Limosa l. limosa in The Netherlands is not explained by changes in adult survival

    NARCIS (Netherlands)

    Roodbergen, M.; Klok, C.; Schekkerman, H.

    2008-01-01

    The Black-tailed Godwit Limosa limosa is a characteristic breeding wader of wet grasslands in the Netherlands which has suffered a strong population decline since the 1960s. Low breeding success has been implicated as the main driver of this decline and here we examine whether changes in adult

  3. Analysis of the Causes of a Decline in the San Joaquin Kit Fox Population on the Elk Hills, Naval Petroleum Reserve #1, California

    Science.gov (United States)

    EPA is announcing the availability of the final report, Analysis of the Causes of a Decline in the San Joaquin Kit Fox Population on the Elk Hills, Naval Petroleum Reserve #1, California. This report describes a causal assessment of the decline in the abundance of San Joaq...

  4. Recent population decline and selection shape diversity of taxol-related genes.

    Science.gov (United States)

    Burgarella, C; Navascués, M; Zabal-Aguirre, M; Berganzo, E; Riba, M; Mayol, M; Vendramin, G G; González-Martínez, S C

    2012-06-01

    Taxanes are defensive metabolites produced by Taxus species (yews) and used in anticancer therapies. Despite their medical interest, patterns of natural diversity in taxane-related genes are unknown. We examined variation at five main genes of Taxus baccata in the Iberian Peninsula, a region where unique yew genetic resources are endangered. We looked at several gene features and applied complementary neutrality tests, including diversity/divergence tests, tests solely based on site frequency spectrum (SFS) and Zeng's compound tests. To account for specific demography, microsatellite data were used to infer historical changes in population size based on an Approximate Bayesian Computation (ABC) approach. Polymorphism-divergence tests pointed to positive selection for genes TBT and TAT and balancing selection for DBAT. In addition, neutrality tests based on SFS found that while a recent reduction in population size may explain most statistics' values, selection may still be in action in genes TBT and DBAT, at least in some populations. Molecular signatures on taxol genes suggest the action of frequent selective waves with different direction or intensity, possibly related to varying adaptive pressures produced by the host-enemy co-evolution on defence-related genes. Such natural selection processes may have produced taxane variants still undiscovered. © 2012 Blackwell Publishing Ltd.

  5. Genetic consequences of population decline in Eurasian otter (Lutra lutra) populations in the Czech and Slovak Republics

    Czech Academy of Sciences Publication Activity Database

    Gettová, Lenka; Hájková, Petra

    Supp., - (2011), s. 102 ISSN 0394-1914. [International Otter Colloquium /11./. 30.08.2011-04.09.2011, Pavia] R&D Projects: GA AV ČR KJB600930804 Institutional research plan: CEZ:AV0Z60930519 Keywords : Eurasian otter * population size Subject RIV: EG - Zoology http://www.internationalottercolloquium2010.eu/files/proceedings_iucn_xi_ioc_2011.pdf

  6. A Study of the Effects of Gas Well Compressor Noise on Breeding Bird Populations of the Rattlesnake Canyon Habitat Management Area, San Juan County, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    LaGory, K.E.; Chang, Young-Soo; Chun, K.C.; Reeves, T.; Liebich, R.; Smith, K.

    2001-06-04

    This report, conducted from May through July 2000, addressed the potential effect of compressor noise on breeding birds in gas-production areas administered by the FFO, specifically in the Rattlesnake Canyon Habitat Management Area northeast of Farmington, New Mexico. The study was designed to quantify and characterize noise output from these compressors and to determine if compressor noise affected bird populations in adjacent habitat during the breeding season.

  7. Mixing plants from different origins to restore a declining population: ecological outcomes and local perceptions 10 years later.

    Directory of Open Access Journals (Sweden)

    Anne-Claire Maurice

    Full Text Available 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.

  8. Mixing Plants from Different Origins to Restore a Declining Population: Ecological Outcomes and Local Perceptions 10 Years Later

    Science.gov (United States)

    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

  9. The Bird.

    Science.gov (United States)

    Hannon, Jean

    2001-01-01

    Students use a dead bird to learn about bird life, anatomy, and death. Students examine a bird body and discuss what happened to the bird. Uses outdoor education as a resource for learning about animals. (SAH)

  10. The role of selection and historical factors in driving population differentiation along an elevational gradient in an island bird.

    Science.gov (United States)

    Bertrand, J A M; Delahaie, B; Bourgeois, Y X C; Duval, T; García-Jiménez, R; Cornuault, J; Pujol, B; Thébaud, C; Milá, B

    2016-04-01

    Adaptation to local environmental conditions and the range dynamics of populations can influence evolutionary divergence along environmental gradients. Thus, it is important to investigate patterns of both phenotypic and genetic variations among populations to reveal the respective roles of these two types of factors in driving population differentiation. Here, we test for evidence of phenotypic and genetic structure across populations of a passerine bird (Zosterops borbonicus) distributed along a steep elevational gradient on the island of Réunion. Using 11 microsatellite loci screened in 401 individuals from 18 localities distributed along the gradient, we found that genetic differentiation occurred at two spatial levels: (i) between two main population groups corresponding to highland and lowland areas, respectively, and (ii) within each of these two groups. In contrast, several morphological traits varied gradually along the gradient. Comparison of neutral genetic differentiation (FST ) and phenotypic differentiation (PST ) showed that PST largely exceeds FST at several morphological traits, which is consistent with a role for local adaptation in driving morphological divergence along the gradient. Overall, our results revealed an area of secondary contact midway up the gradient between two major, cryptic, population groups likely diverged in allopatry. Remarkably, local adaptation has shaped phenotypic differentiation irrespective of population history, resulting in different patterns of variation along the elevational gradient. Our findings underscore the importance of understanding both historical and selective factors when trying to explain variation along environmental gradients. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

  11. Bird Use of Grassland Habitat Patches at a Military Airfield

    Science.gov (United States)

    In light of reported declines in grassland bird populations in North America, information about their use of airfield habitats can help inform management decisions in the context of conflicting objectives of minimizing wildlife-aircraft collisions and helping to conserve grasslan...

  12. Bird banding and climate change: can we make a difference?

    Science.gov (United States)

    C. John Ralph; Jared D. Wolfe

    2014-01-01

    So how does your banding effort fit into the new paradigm of climate science? A little background: many bird populations underwent mass declines during the 19th century from a variety of causes including hunting and habitat change. Current human-induced climate change represents a new and fast-acting pressure that is inherently more difficult to curtail and may drive...

  13. Condition varies with habitat choice in postbreeding forest birds

    Science.gov (United States)

    Scott H. Stoleson

    2013-01-01

    Many birds that are experiencing population declines require extensive tracts of mature forest habitat for breeding. Recent work suggests that at least some may shift their habitat use to early-successional areas after nesting but before migration. I used constant-effort mist netting in regenerating clearcuts (4-8 years postcut) and dense mature-forest understories to...

  14. Regional Forest Fragmentation and the Nesting Success of Migratory Birds

    Science.gov (United States)

    Scott K. Robinson; Frank R. Thompson III; Therese M. Donovan; Donald R. Whitehead; John Faaborg

    1995-01-01

    Forest fragmentation, the disruption in the continuity of forest habitat, is hypothesized to be a major cause of population decline for, some species of forest birds because fragmentation reduces nesting (reproductive) success. Nest predation and parasitism by cowbirds increased with forest fragmentation in nine midwestern (United States)landscapes that varied from 6...

  15. Population Studies of Tidal Marsh Breeding Birds at Rush Ranch: A Synthesis

    OpenAIRE

    Spautz, Hildie; Liu, Leonard; Estrella, Sarah; Nur, Nadav

    2012-01-01

    Rush Ranch, with the largest contiguous area of fully-tidal marsh remaining in northern Suisun Bay, is critical habitat for a number of endemic bird species that breed in brackish tidal marsh. Despite the abundance of non-native invasive plants (particularly perennial pepperweed, Lepidium latifolium) and altered hydrology, it is the best remaining representative in Solano County of the tidal marsh that once covered more than 27,000 ha (67,000 acres) in Suisun Bay. This paper presents a synthe...

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

    Science.gov (United States)

    Mcphie, R P; Campana, S E

    2009-07-01

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

  17. Genetic consequences of population decline in the European otter (Lutra lutra): an assessment of microsatellite DNA variation in Danish otters from 1883 to 1993.

    OpenAIRE

    Pertoldi, C.; Hansen, M. M.; Loeschcke, V.; Madsen, A. B.; Jacobsen, L.; Baagoe, H.

    2001-01-01

    The European otter (Lutra lutra) was common in Denmark until the 1960s, but its present distribution encompasses only a minor part of the country. The aim of this study was to assess whether the recent population decline has resulted in loss of genetic variability and to gain further insight into the dynamics of the population decline. This was done by analysing microsatellite DNA variation in contemporary and historical samples, the latter encompassing DNA samples extracted from museum speci...

  18. Can Citizen Science Assist in Determining Koala (Phascolarctos cinereus Presence in a Declining Population?

    Directory of Open Access Journals (Sweden)

    Emily Flower

    2016-07-01

    Full Text Available 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.

  19. Effects of population based screening for Chlamydia infections in the Netherlands limited by declining participation rates.

    Directory of Open Access Journals (Sweden)

    Boris V Schmid

    Full Text Available BACKGROUND: A large trial to investigate the effectiveness of population based screening for chlamydia infections was conducted in the Netherlands in 2008-2012. The trial was register based and consisted of four rounds of screening of women and men in the age groups 16-29 years in three regions in the Netherlands. Data were collected on participation rates and positivity rates per round. A modeling study was conducted to project screening effects for various screening strategies into the future. METHODS AND FINDINGS: We used a stochastic network simulation model incorporating partnership formation and dissolution, aging and a sexual life course perspective. Trends in baseline rates of chlamydia testing and treatment were used to describe the epidemiological situation before the start of the screening program. Data on participation rates was used to describe screening uptake in rural and urban areas. Simulations were used to project the effectiveness of screening on chlamydia prevalence for a time period of 10 years. In addition, we tested alternative screening strategies, such as including only women, targeting different age groups, and biennial screening. Screening reduced prevalence by about 1% in the first two screening rounds and leveled off after that. Extrapolating observed participation rates into the future indicated very low participation in the long run. Alternative strategies only marginally changed the effectiveness of screening. Higher participation rates as originally foreseen in the program would have succeeded in reducing chlamydia prevalence to very low levels in the long run. CONCLUSIONS: Decreasing participation rates over time profoundly impact the effectiveness of population based screening for chlamydia infections. Using data from several consecutive rounds of screening in a simulation model enabled us to assess the future effectiveness of screening on prevalence. If participation rates cannot be kept at a sufficient level

  20. Sugar Deprivation Reduces Insemination of Anopheles gambiae (Diptera: Culicidae), Despite Daily Recruitment of Adults, and Predicts Decline in Model Populations

    Science.gov (United States)

    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

  1. 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.

    Science.gov (United States)

    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.

  2. 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.

    Directory of Open Access Journals (Sweden)

    Jessica Stapley

    Full Text Available 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.

  3. Molecular analysis of stomach contents reveals important grass seeds in the winter diet of Baird's and Grasshopper sparrows, two declining grassland bird species.

    Science.gov (United States)

    Titulaer, Mieke; Melgoza-Castillo, Alicia; Panjabi, Arvind O; Sanchez-Flores, Alejandro; Martínez-Guerrero, José Hugo; Macías-Duarte, Alberto; Fernandez, Jesús A

    2017-01-01

    We analyzed the diet of Baird's Sparrow (Ammodramus bairdii) and Grasshopper Sparrow (A. savannarum) in three different sites and sampling periods across the Chihuahuan Desert in northern Mexico. DNA from seeds in regurgitated stomach contents was sequenced using NGS technology and identified with a barcoding approach using the P6 loop of the trnL intron as genetic marker. During each sampling period, we collected random soil samples to estimate seed availability in the soil seed bank. Due to the variability and size of the genetic marker, the resolution was limited to a family level resolution for taxonomic classification of seeds, but in several cases a genus level was achieved. Diets contained a high diversity of seeds but were dominated by a limited number of genera/families. Seeds from Panicoideae (from the genera Panicum, Setaria, Eriochloa, Botriochloa, and Hackelochloa) contributed for the largest part to the diets (53 ± 19%), followed by Bouteloua (10 ± 12%). Depending on the site and sampling period, other important seeds in the diets were Eragrostideae, Pleuraphis, Asteraceae, Verbena, and Amaranthus. The most abundant seeds were not always preferred. Aristida and Chloris were common in the soil seed bank but these seeds were avoided by both bird species. Baird's and Grasshopper sparrows did not differ in seed preferences. This work highlights the importance of range management practices that favor seed production of Panicoideae and Bouteloua grasses to enhance winter habitat use and survival of Baird's and Grasshopper sparrows in the Chihuahuan Desert.

  4. [Spatial distribution characteristics of urban potential population in Shenyang City based on QuickBird image and GIS].

    Science.gov (United States)

    Li, Jun-Ying; Hu, Yuan-Man; Chen, Wei; Liu, Miao; Hu, Jian-Bo; Zhong, Qiao-Lin; Lu, Ning

    2012-06-01

    Population is the most active factor affecting city development. To understand the distribution characteristics of urban population is of significance for making city policy decisions and for optimizing the layout of various urban infrastructures. In this paper, the information of the residential buildings in Shenyang urban area was extracted from the QuickBird remote sensing images, and the spatial distribution characteristics of the population within the Third-Ring Road of the City were analyzed, according to the social and economic statistics data. In 2010, the population density in different types of residential buildings within the Third-Ring Road of the City decreased in the order of high-storey block, mixed block, mixed garden, old multi-storey building, high-storey garden, multi-storey block, multi-storey garden, villa block, shanty, and villa garden. The vacancy rate of the buildings within the Third-Ring Road was more than 30%, meaning that the real estate market was seriously overstocked. Among the five Districts of Shenyang City, Shenhe District had the highest potential population density, while Tiexi District and Dadong District had a lower one. The gravity center of the City and its five Districts was also analyzed, which could provide basic information for locating commercial facilities and planning city infrastructure.

  5. 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

    Science.gov (United States)

    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.

  6. Radionuclides and the birds at Ravenglass

    International Nuclear Information System (INIS)

    Lowe, V.P.W.

    1991-01-01

    Since 1983 concern has been expressed about the apparent decline in numbers of birds in the Ravenglass estuary in west Cumbria, particularly of the black-headed gull colony on the Drigg dunes, and suggestions have been made that this decline might be due to excessive radiation in the birds' food and their general environment. Twelve species of marine invertebrates from Ravenglass, known to be important foods for birds, were analysed, and further samples were taken from sites along the west Cumbrian coast. None of these samples showed excessive contamination with any of the radionuclides analysed. Analysis of a sample of bird carcasses from the area showed oystercatchers (Haematopus ostralegus) and shelduck (Tadorna tadorna) to have some of the highest concentrations of 137 Cs in their tissues; yet their breeding success and populations were not affected. Black-headed gulls were found to be feeding mainly inland, and were the least contaminated with radionuclides of all the birds at Ravenglass, yet this species and its breeding success were in decline. Calculations of the total dose equivalent rate to the whole body of the most contaminated black-headed gull amounted to 9.8 x 10 -4 mSv h -1 (∼ 8.4 x 10 -4 mGy h -1 , whole-body absorbed dose rate), and the background exposure dose was of the order of 8.3 x 10 -4 mGy h -1 . As a minimum chronic dose of 1000 mGy day -1 has been found necessary to retard growth of nestling birds, and 9600 mGy over 20 days of incubation to cause the death of 50% of embryos in black-headed gulls' eggs, the concentrations of radionuclides in the foods, body tissues and general environment were at least three orders of magnitude too low to have had any effects. (author)

  7. Disruption of Rhino Demography by Poachers May Lead to Population Declines in Kruger National Park, South Africa.

    Directory of Open Access Journals (Sweden)

    Sam M Ferreira

    Full Text Available 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.

  8. Disruption of Rhino Demography by Poachers May Lead to Population Declines in Kruger National Park, South Africa.

    Science.gov (United States)

    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.

  9. Landscape-based population viability models demonstrate importance of strategic conservation planning for birds

    Science.gov (United States)

    Thomas W. Bonnot; Frank R. Thompson; Joshua J. Millspaugh; D. Todd. Jones-Farland

    2013-01-01

    Efforts to conserve regional biodiversity in the face of global climate change, habitat loss and fragmentation will depend on approaches that consider population processes at multiple scales. By combining habitat and demographic modeling, landscape-based population viability models effectively relate small-scale habitat and landscape patterns to regional population...

  10. Trans-generational effects on ageing in a wild bird population

    NARCIS (Netherlands)

    Bouwhuis, S.; Charmantier, A.; Verhulst, S.; Sheldon, B. C.

    Ageing, long thought to be too infrequent to study effectively in natural populations, has recently been shown to be ubiquitous, even in the wild. A major challenge now is to explain variation in the rates of ageing within populations. Here, using 49 years of data from a population of great tits

  11. Effects of illegal harvest of eggs on the population decline of leatherback turtles in Las Baulas Marine National Park, Costa Rica.

    Science.gov (United States)

    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.

  12. The Significance of Mating System and Nonbreeding Behavior to Population and Forest Patch Use by Migrant Birds

    Science.gov (United States)

    Eugene S. Morton; Bridget J. M. Stutchbury

    2005-01-01

    Migratory birds are birds of two worlds, breeding in the temperate zone then living as tropical birds for most of the year. We show two aspects of this unique biology that are important considerations for their conservation. First, habitat selection for breeding must include their need for extra-pair mating opportunities. Second, non-breeding distributions in tropical...

  13. Filling the gaps: Using count survey data to predict bird density distribution patterns and estimate population sizes

    NARCIS (Netherlands)

    Sierdsema, H.; van Loon, E.E.

    2008-01-01

    Birds play an increasingly prominent role in politics, nature conservation and nature management. As a consequence, up-to-date and reliable spatial estimates of bird distributions over large areas are in high demand. The requested bird distribution maps are however not easily obtained. Intensive

  14. A 5-year Chlamydia vaccination programme could reverse disease-related koala population decline: predictions from a mathematical model using field data.

    Science.gov (United States)

    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

  15. Climate-associated population declines reverse recovery and threaten future of an iconic high-elevation plant

    Science.gov (United States)

    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.

  16. The European and Japanese outbreaks of H5N8 derive from a single source population providing evidence for the dispersal along the long distance bird migratory flyways.

    Science.gov (United States)

    Dalby, Andrew R; Iqbal, Munir

    2015-01-01

    The origin of recent parallel outbreaks of the high pathogenicity H5N8 avian flu virus in Europe and in Japan can be traced to a single source population, which has most likely been spread by migratory birds. By using Bayesian coalescent methods to analyze the DNA sequences of the virus to find the times for divergence and combining this sequence data with bird migration data we can show the most likely locations and migratory pathways involved in the origin of the current outbreak. This population was most likely located in the Siberian summer breeding grounds of long-range migratory birds. These breeding grounds provide a connection between different migratory flyways and explain the current outbreaks in remote locations. By combining genetic methods and epidemiological data we can rapidly identify the sources and the dispersion pathways for novel avian influenza outbreaks.

  17. The European and Japanese outbreaks of H5N8 derive from a single source population providing evidence for the dispersal along the long distance bird migratory flyways

    Directory of Open Access Journals (Sweden)

    Andrew R. Dalby

    2015-04-01

    Full Text Available The origin of recent parallel outbreaks of the high pathogenicity H5N8 avian flu virus in Europe and in Japan can be traced to a single source population, which has most likely been spread by migratory birds. By using Bayesian coalescent methods to analyze the DNA sequences of the virus to find the times for divergence and combining this sequence data with bird migration data we can show the most likely locations and migratory pathways involved in the origin of the current outbreak. This population was most likely located in the Siberian summer breeding grounds of long-range migratory birds. These breeding grounds provide a connection between different migratory flyways and explain the current outbreaks in remote locations. By combining genetic methods and epidemiological data we can rapidly identify the sources and the dispersion pathways for novel avian influenza outbreaks.

  18. Predictive abilities of cardiovascular biomarkers to rapid decline of renal function in Chinese community-dwelling population: a 5-year prospective analysis.

    Science.gov (United States)

    Fu, Shihui; Liu, Chunling; Luo, Leiming; Ye, Ping

    2017-11-09

    Predictive abilities of cardiovascular biomarkers to renal function decline are more significant in Chinese community-dwelling population without glomerular filtration rate (GFR) below 60 ml/min/1.73m 2 , and long-term prospective study is an optimal choice to explore this problem. Aim of this analysis was to observe this problem during the follow-up of 5 years. In a large medical check-up program in Beijing, there were 948 participants with renal function evaluated at baseline and follow-up of 5 years. Physical examinations were performed by well-trained physicians. Blood samples were analyzed by qualified technicians in central laboratory. Median rate of renal function decline was 1.46 (0.42-2.91) mL/min/1.73m 2 /year. Rapid decline of renal function had a prevalence of 23.5% (223 participants). Multivariate linear and Logistic regression analyses confirmed that age, sex, baseline GFR, homocysteine and N-terminal pro B-type natriuretic peptide (NT-proBNP) had independently predictive abilities to renal function decline rate and rapid decline of renal function (p rapid decline of renal function (p > 0.05 for all). Homocysteine and NT-proBNP rather than hs-cTnT had independently predictive abilities to rapid decline of renal function in Chinese community-dwelling population without GFR below 60 ml/min/1.73m 2 . Baseline GFR was an independent factor predicting the rapid decline of renal function. Arterial stiffness and compliance had no independent effect on rapid decline of renal function. This analysis has a significant implication for public health, and changing the homocysteine and NT-proBNP levels might slow the rapid decline of renal function.

  19. Population expansion of some bird species in the city of Wrocław

    Directory of Open Access Journals (Sweden)

    Kopij Grzegorz

    2016-12-01

    Full Text Available During the years 2002-2010, distribution and numbers of eight bird species were studied in the whole city of Wrocław, SW Poland (293 km2. The estimation for these species are as follow: Streptopelia turtur: 3 breeding pairs, Upupa epops: 1, Cuculus canorus: 49, Emberiza hortulana: 7, Luscinia megarhynchos: 214-286, Phoenicurus phoenicurus: 87-118, Turdus pilaris: 105-150, Hippolais icterina: 136-181. In comparison with 1980‘s and 1990’s, a rapid increase in the numbers P. phoenicurus, and T. pilaris, and a slight increase of L. megarhynchos and Cuculus canorus were documented. T. pilaris began to breed in the city in the end of 1990‘s. The increase may indicate that the habitats in Wrocław improved both in regard to food availability, nesting sites and other environmental requisitions. The increase in the numbers recorded for C. canorus, P. phoe-nicurus, and L. megarhynchos may also be a result of good conditions prevailing in their wintering grounds in sub-Saharan Africa.

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

    NARCIS (Netherlands)

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

    2010-01-01

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

  1. Pesticides, Persecution and Legal Protection Population effects on birds of prey.

    NARCIS (Netherlands)

    Arkes, Margit; Butter, Maureen (ed.).

    1997-01-01

    This report reviews the effects of pesticides, persecution and legal protection from a population perspective. In the past, legal hunting and organochlorine pesticides severely affected raptor populations. What lessons can be learned for the future? Is a second mass extinction, by other

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

    Science.gov (United States)

    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

  3. Estimating trends of population decline in long-lived marine species in the Mediterranean Sea based on fishers' perceptions.

    Science.gov (United States)

    Maynou, Francesc; Sbrana, Mario; Sartor, Paolo; Maravelias, Christos; Kavadas, Stefanos; Damalas, Dimitros; Cartes, Joan E; Osio, Giacomo

    2011-01-01

    We conducted interviews of a representative sample of 106 retired fishers in Italy, Spain and Greece, asking specific questions about the trends they perceived in dolphin and shark abundances between 1940 and 1999 (in three 20 year periods) compared to the present abundance. The large marine fauna studied were not target species of the commercial fleet segment interviewed (trawl fishery). The fishers were asked to rank the perceived abundance in each period into qualitative ordinal classes based on two indicators: frequency of sightings and frequency of catches (incidental or intentional) of each taxonomic group. The statistical analysis of the survey results showed that both incidental catches and the sighting frequency of dolphins have decreased significantly over the 60+ years of the study period (except for in Greece due to the recent population increase). This shows that fishers' perceptions are in agreement with the declining population trends detected by scientists. Shark catches were also perceived to have diminished since the early 1940s for all species. Other long-lived Mediterranean marine fauna (monk seals, whales) were at very low levels in the second half of the 20(th) century and no quantitative data could be obtained. Our study supports the results obtained in the Mediterranean and other seas that show the rapid disappearance (over a few decades) of marine fauna. We show that appropriately designed questionnaires help provide a picture of animal abundance in the past through the valuable perceptions of fishers. This information can be used to complement scientific sources or in some cases be taken as the only information source for establishing population trends in the abundance of sensitive species.

  4. Maryland ESI: BIRDS (Bird Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for wading birds, shorebirds, waterfowl, raptors, diving birds, seabirds, passerine birds, and gulls and...

  5. Alabama ESI: BIRDS (Bird Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for wading birds, shorebirds, waterfowl, raptors, diving birds, seabirds, passerine birds, gulls, and terns...

  6. The forms and fitness cost of senescence : Age-specific recapture, survival, reproduction, and reproductive value in a wild bird population

    NARCIS (Netherlands)

    Bouwhuis, Sandra; Choquet, Remi; Sheldon, Ben C.; Verhulst, Simon

    Longitudinal studies of senescence accumulate rapidly from natural populations. However, it is largely unknown whether different fitness components senesce in parallel, how reproductive and survival senescence contribute to declines in reproductive value, and how large the fitness cost of senescence

  7. Ancient and contemporary DNA reveal a pre-human decline but no population bottleneck associated with recent human persecution in the kea (Nestor notabilis).

    Science.gov (United States)

    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.

  8. Ancient and contemporary DNA reveal a pre-human decline but no population bottleneck associated with recent human persecution in the kea (Nestor notabilis.

    Directory of Open Access Journals (Sweden)

    Nicolas Dussex

    Full Text Available 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.

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

    Science.gov (United States)

    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

  10. East Africa's diminishing bird habitats and bird species

    African Journals Online (AJOL)

    ... resultant intensive agricultural projects that follow. Such impacts have resulted in a decline in both bird habitats and biodiversity. Of particular concern are the areas important to all our endemic bird species, and already we are witnessing a series of very worrying developments. Taking each. Scopus 32: 27–34, June 2013 ...

  11. The European and Japanese outbreaks of H5N8 derive from a single source population providing evidence for the dispersal along the long distance bird migratory flyways

    OpenAIRE

    Andrew R. Dalby; Munir Iqbal

    2015-01-01

    The origin of recent parallel outbreaks of the high pathogenicity H5N8 avian flu virus in Europe and in Japan can be traced to a single source population, which has most likely been spread by migratory birds. By using Bayesian coalescent methods to analyze the DNA sequences of the virus to find the times for divergence and combining this sequence data with bird migration data we can show the most likely locations and migratory pathways involved in the origin of the current outbreak. This popu...

  12. Raptors in the State Nature Reserve “Kerzhensky” After Forest Fires of 2010: Materials of Five-Year Monitoring of a Summer Bird Population

    Directory of Open Access Journals (Sweden)

    Olga S. Noskova

    2016-04-01

    Full Text Available On the basis of five-year monitoring data on summer bird population in the Nature Reserve “Kerzhensky” after the catastrophic fires of 2010, a spatial distribution of raptors was analyzed (mainly birds of prey – Falconiformes. Main types of habitats were surveyed using line transect counts. In total 17 species of raptors were observed. Abundance of each species is presented here. Northern Goshawk (Accipiter gentilis, Eurasian Sparrowhawk (Accipiter nisus, Common Buzzard (Buteo buteo and Eurasian Hobby (Falco subbuteo were the most common species of raptors in the Nature Reserve.

  13. Decline in Mycobacterium bovis and Brucella abortus populations during the maturation of experimentally contaminated parmesan-type cheese

    Directory of Open Access Journals (Sweden)

    Karina Ramirez Starikoff

    2016-11-01

    Full Text Available Brazilian legislation allows the manufacture of raw milk cheese with a maturation exceeding 60 days at room temperature above 5°C, but there is a lack of solid scientific evidence on the efficacy of this maturation process in inactivating important pathogens that may be present in milk, such as Mycobacterium bovis and Brucella abortus. Thus, the objectives of this study were to produce parmesan-type cheese experimentally contaminated with M. bovis and B. abortus and evaluate the survival of these pathogens along 2-month maturation. Parmesan-type cheese was manufactured in the laboratory using whole pasteurized milk with or without inoculation with M. bovis (SB1033 or B. abortus (1119-3 and matured at 18°C for up to 63 days. M. bovis was inoculated in Stonebrink-Leslie medium supplemented with antibiotics and incubated at 37°C for 45 days, and B. abortus was incubated in Farrel medium at 36°C for 3 days. The average D18°C value, weighted by variance, was 37.5 ± 5.3 days for M. bovis and 5.9 ± 0.7 days for B. abortus. The average physicochemical parameters in the cheese at the end of the study were as follows: pH = 4.89, water activity = 0.976, and moisture percentage = 43.1%. The pH might have contributed to the reduction in the population of B. abortus but seems not to have influenced the population of M. bovis. We conclude that the duration of the maturation process influences the size of the surviving populations of M. bovis and B. abortus, and that the shortening of the maturation duration might not ensure a decline in pathogen levels to safe levels. Thus, complementary studies considering the effect of several other technological aspects on the survival of these pathogens are required, including the effect of the lactic acid bacterial population, salt content, and temperature of maturation.

  14. Self-reported health status as a predictor of functional decline in a community-dwelling elderly population: Nationwide longitudinal survey in Korea.

    Science.gov (United States)

    Kim, Sang Hyuck; Cho, Belong; Won, Chang Won; Hong, Young Ho; Son, Ki Young

    2017-06-01

    As the elderly population is increasing, the prediction and prevention of functional decline in older adults are of great concern. The present study aimed to evaluate whether poor self-reported health status (SRHS) could predict functional decline after 2 years in the elderly population. Data from the Korean Longitudinal Study of Aging panel, a national representative sample of aging Koreans, were used. Participants of the investigation were the elderly population aged 65 years or more without disability in carrying out activities of daily living (ADL) at baseline. The survey asked respondents about their subjective health status. Setting the respondents who stated their health status as "very good" or "good" as the reference group, multivariable logistic regression analysis was carried out to compare functional decline according to the baseline SRHS. A total of 2824 participants were included in the analysis. Among them, 138 (4.9 %) reported functional decline of at least one of the seven ADL components after 2 years. In multivariable logistic regression analysis, SRHS was significantly associated with subsequent functional decline in respondents who chose "Bad" (odds ratio 3.32, 95% confidence interval 1.71-6.44) or "Very bad" (OR 4.75, 95% CI 2.12-10.66). Furthermore, poorer SRHS was significantly associated with subsequent impairment in each ADL component. Also, SRHS predicted overall subsequent impairment in the instrumental ADL. SRHS predicted functional decline after 2 years in older adults without baseline disabilities. SRHS can be a good predictor of future functional decline in the elderly population. Geriatr Gerontol Int 2017; 17: 885-892. © 2016 Japan Geriatrics Society.

  15. No association between personality and candidate gene polymorphisms in a wild bird population

    NARCIS (Netherlands)

    Edwards, Hannah A.; Hajduck, GK; Durieux, G; Burke, T; Dugdale, Hannah

    2015-01-01

    Consistency of between-individual differences in behaviour or personality is a phenomenon in populations that can have ecological consequences and evolutionary potential. One way that behaviour can evolve is to have a genetic basis. Identifying the molecular genetic basis of personality could

  16. Migratory connectivity and population-specific migration routes in a long-distance migratory bird

    NARCIS (Netherlands)

    Trierweiler, Christiane; Klaassen, Raymond H.G.; Drent, Rudi H.; Exo, Klaus-Michael; Komdeur, Jan; Bairlein, Franz; Koks, Ben J.

    2014-01-01

    Knowledge about migratory connectivity, the degree to which individuals from the same breeding site migrate to the same wintering site, is essential to understand processes affecting populations of migrants throughout the annual cycle. Here, we study the migration system of a long-distance migratory

  17. Birds protected by national legislation show improved population trends in Eastern Europe

    Czech Academy of Sciences Publication Activity Database

    Koleček, Jaroslav; Schleuning, M.; Burfield, I. J.; Báldi, A.; Böhning-Gaese, K.; Devictor, V.; Fernández-García, J. M.; Hořák, D.; Van Turnhout, C. A. M.; Hnatyna, O.; Reif, J.

    2014-01-01

    Roč. 172, April (2014), s. 109-116 ISSN 0006-3207 Institutional support: RVO:68081766 Keywords : Conservation effectiveness * Ecological trait * Environmental legislation * Global change * Life history strategy * Population growth rate Subject RIV: EG - Zoology Impact factor: 3.762, year: 2014

  18. Interactions between Behaviour and Genetics in Wild and Domestic Bird Populations

    NARCIS (Netherlands)

    Rodenburg, T.B.; Oers, van K.

    2010-01-01

    Personality traits can be favoured by both natural and artificial selection, if they result in increased fitness or productivity, and therefore play an important role in both wild and domestic populations. Here, we review how personality traits affect and are affected by natural and artificial

  19. Seroprevalence of avian paramyxovirus 1, 2, and 3 in captive and free-living birds of prey in Spain (preliminary results): implications for management of wild and captive populations.

    Science.gov (United States)

    Höfle, Ursula; Blanco, J M; Kaleta, E F

    2002-10-01

    Since December 1997, 700 blood plasma samples from 31 different species of captive and free-living birds of prey from Spain were analyzed by hemagglutination inhibition (HI) test for the presence of antibodies to avian paramyxovirus (aPMV) 1,2, and 3. Out of 700 birds, 120 tested positive for aPMV-1, 10 birds had antibodies to aPMV-2, and 4 birds tested positive against aPMV-3. Prevalence of antibodies against aPMV-1 was significantly higher in captive than in free-living birds of prey and in Falconiformes than in Strigidae and Accipitridae. Infection or exposure in captive birds may be due to the use of avian-derived food in rehabilitation and captive-breeding centers. This may be of concern at the time of reintroduction of these birds into free-living populations.

  20. The environmental dependence of inbreeding depression in a wild bird population.

    Directory of Open Access Journals (Sweden)

    Marta Szulkin

    2007-10-01

    Full Text Available Inbreeding depression occurs when the offspring produced as a result of matings between relatives show reduced fitness, and is generally understood as a consequence of the elevated expression of deleterious recessive alleles. How inbreeding depression varies across environments is of importance for the evolution of inbreeding avoidance behaviour, and for understanding extinction risks in small populations. However, inbreeding-by-environment (IxE interactions have rarely been investigated in wild populations.We analysed 41 years of breeding events from a wild great tit (Parus major population and used 11 measures of the environment to categorise environments as relatively good or poor, testing whether these measures influenced inbreeding depression. Although inbreeding always, and environmental quality often, significantly affected reproductive success, there was little evidence for statistically significant I x E interactions at the level of individual analyses. However, point estimates of the effect of the environment on inbreeding depression were sometimes considerable, and we show that variation in the magnitude of the I x E interaction across environments is consistent with the expectation that this interaction is more marked across environmental axes with a closer link to overall fitness, with the environmental dependence of inbreeding depression being elevated under such conditions. Hence, our analyses provide evidence for an environmental dependence of the inbreeding x environment interaction: effectively an I x E x E.Overall, our analyses suggest that I x E interactions may be substantial in wild populations, when measured across relevant environmental contrasts, although their detection for single traits may require very large samples, or high rates of inbreeding.

  1. Breeding ecology of the southern shrike, Lanius meridionalis, in an agrosystem of south–eastern Spain: the surprisingly excellent breeding success in a declining population

    Energy Technology Data Exchange (ETDEWEB)

    Moreno-Rueda, G.; Abril-Colon, I.; Lopez-Orta, A.; Alvarez-Benito, I.; Castillo-Gomez, C.; Comas, M.; Rivas, J.M.

    2016-07-01

    The southern shrike, Lanius meridionalis, is declining at the Spanish and European level. One cause of this decline could be low reproductive success due to low availability of prey in agricultural environments. To investigate this possibility we analysed the breeding ecology of a population of southern shrike in an agrosystem in Lomas de Padul (SE Spain). Our results suggest the population is declining in this area. However, contrary to expectations, the population showed the highest reproductive success (% nests in which at least one egg produces a fledgling) reported for this species to date (83.3%), with a productivity of 4.04 fledglings per nest. Reproductive success varied throughout the years, ranging from 75% in the worst year to 92.9% in the best year. Similarly, productivity ranged from 3.25 to 5.0 fledglings per nest depending on the year. Other aspects of reproductive biology, such as clutch size, brood size, and nestling diet, were similar to those reported in other studies. Based on these results, we hypothesise that the determinant of population decline acts on the juvenile fraction, drastically reducing the recruitment rate, or affecting the dispersion of adults and recruits. Nevertheless, the exact factor or factors are unknown. This study shows that a high reproductive success does not guarantee good health status of the population. (Author)

  2. Metabolic syndrome but not obesity measures are risk factors for accelerated age-related glomerular filtration rate decline in the general population.

    Science.gov (United States)

    Stefansson, Vidar T N; Schei, Jørgen; Solbu, Marit D; Jenssen, Trond G; Melsom, Toralf; Eriksen, Bjørn O

    2018-01-22

    Rapid age-related glomerular filtration rate (GFR) decline increases the risk of end-stage renal disease, and a low GFR increases the risk of mortality and cardiovascular disease. High body mass index and the metabolic syndrome are well-known risk factors for patients with advanced chronic kidney disease, but their role in accelerating age-related GFR decline independent of cardiovascular disease, hypertension and diabetes is not adequately understood. We studied body mass index, waist circumference, waist-hip ratio and metabolic syndrome as risk factors for accelerated GFR decline in 1261 middle-aged people representative of the general population without diabetes, cardiovascular disease or kidney disease. GFR was measured as iohexol clearance at baseline and repeated after a median of 5.6 years. Metabolic syndrome was defined as fulfilling three out of five criteria, based on waist circumference, blood pressure, glucose, high-density lipoprotein cholesterol and triglycerides. The mean GFR decline rate was 0.95 ml/min/year. Neither the body mass index, waist circumference nor waist-hip ratio predicted statistically significant changes in age-related GFR decline, but individuals with baseline metabolic syndrome had a significant mean of 0.30 ml/min/year faster decline than individuals without metabolic syndrome in a multivariable adjusted linear regression model. This association was mainly driven by the triglyceride criterion of metabolic syndrome, which was associated with a significant 0.36 ml/min/year faster decline when analyzed separately. Results differed significantly when GFR was estimated using creatinine and/or cystatin C. Thus, metabolic syndrome, but not the body mass index, waist circumference or waist-hip ratio, is an independent risk factor for accelerated age-related GFR decline in the general population. Copyright © 2017 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

  3. Strong genetic structure among coral populations within a conservation priority region, the Bird's Head Seascape (Papua, Indonesia

    Directory of Open Access Journals (Sweden)

    Craig John Starger

    2015-11-01

    Full Text Available Marine Protected Areas (MPAs are widely considered to be one of the best strategies available for protecting species diversity and ecosystem processes in marine environments. While data on connectivity and genetic structure of marine populations are critical to designing appropriately sized and spaced networks of MPAs, such data are rarely available. This study examines genetic structure in reef-building corals from Papua and West Papua, Indonesia, one of the most biodiverse and least disturbed coral reef regions in the world. We focused on two common reef-building corals, Pocillopora damicornis (Linnaeus 1758 and Seriatopora hystrix (family: Pocilloporidae, from three regions under different management regimes: Teluk Cenderawasih, Raja Ampat, and southwest Papua. Analyses of molecular variance, assignment tests, and genetical bandwidth mapping based on microsatellite variation revealed significant genetic structure in both species, although there were no clear regional filters to gene flow among regions. Overall, P. damicornis populations were less structured (FST = 0.139, p < 0.00001 than S. hystrix (FST = 0.357, p < 0.00001. Despite occurring in one of the most pristine marine habitats in Indonesia, populations of both species showed evidence of recent declines. Furthermore, exclusion of individual populations from connectivity analyses resulted in marked increases in self-recruitment. Maintaining connectivity within and among regions of Eastern Indonesia will require coral conservation on the local scales and regional networks of MPAs. 

  4. Genetic consequences of population decline in the European otter ( Lutra lutra ) : an assessment of microsatellite DNA variation in Danish otters from 1883 to 1993

    DEFF Research Database (Denmark)

    Pertoldi, C.; Hansen, Michael Møller; Loeschcke, V.

    2001-01-01

    The European otter (Lutra lutra) was common in Denmark until the 1960s, but its present distribution encompasses only a minor part of the country. The aim of this study was to assess whether the recent population decline has resulted in loss of genetic variability and to gain further insight...... alleles, suggested that a drastic long-term population decline has taken place, which could have started more than 2000 years ago, possibly due to ancient anthropogenic pressure. Finally, assignment tests and pairwise F-ST values suggested weak but statistically significant genetic differentiation between...... the extant population and historical samples of otters from other regions in Denmark, more likely reflecting differentiation among original populations rather than recent drift....

  5. Hydroperiod and cattle use associated with lower recruitment in an r-selected amphibian with a declining population trend in the Klamath Mountains, California

    Science.gov (United States)

    Esther M. Cole; Rosemary Hartman; Malcolm P. North

    2016-01-01

    Recent population declines in amphibians associated with mortality in early life stages highlight the need for a better understanding of the environmental factors related to successful survival to metamorphosis. In our study, we closely examine the relative importance of environmental factors to three stages of recruitment for Cascade frogs (Rana cascadae...

  6. Combining the Rowland Universal Dementia Assessment Scale and the Informant Questionnaire on Cognitive Decline in the Elderly to Improve Detection of Dementia in an Arabic-Speaking Population

    DEFF Research Database (Denmark)

    Nielsen, T. Rune; Phung, Thien Kieu Thi; Chaaya, Monique

    2016-01-01

    BACKGROUND/AIMS: The aim of this study was to assess whether combining the Rowland Universal Dementia Assessment Scale (RUDAS) and Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) could improve diagnostic accuracy when screening for dementia in an Arabic-speaking population wi...

  7. The declining Spadefoot toad, Pelobates fuscus (Pelobatidae): Paleo and recent environmental changes as a major influence on current population structure and status

    NARCIS (Netherlands)

    Eggert, C.; Cogalniceanu, D.; Veith, M.K.H.; Dzukic, G.; Taberlet, P.

    2006-01-01

    Populations of the European Spadefoot toad (Pelobates fuscus) have experienced recent declines all over Europe, but these appear to be more intense in north and western Europe. Due to the toad's fossorial nature and specific habitat requirements, environmental conditions have played a major role in

  8. Breeding bird survey data

    Data.gov (United States)

    U.S. Environmental Protection Agency — The data are maintained by the USGS (https://www.pwrc.usgs.gov/bbs/RawData/) and provides information on the trends and status of North American bird populations...

  9. Declination Calculator

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Declination is calculated using the current International Geomagnetic Reference Field (IGRF) model. Declination is calculated using the current World Magnetic Model...

  10. Oak Decline

    Science.gov (United States)

    Philip M. Wargo; David R. Houston; Leon A. LaMadeleine

    1983-01-01

    Periodic occurrences of decline and death of oaks over widespread areas have been recorded since 1900. These outbreaks, variously named oak decline, oak dieback, or oak mortality, are caused by a complex interaction of environmental stresses and pests and given the name oak decline.

  11. Oak Decline

    Science.gov (United States)

    Vernon Ammon; T. Evan Nebeker; Ted H. Filer; Francis I. McCracken; J. D. Solomon; H. E. Kennedy

    1989-01-01

    Occurrence of decline and mortality in this nation's hardwood forests has been documented in reports for the past 130 years. From 1856 through 1981, more than 26 decline events were reported from eight eastern states affecting almost all species of oaks. Fourteen factors have been implicated as either primary or secondary agents responsible for decline and...

  12. Experimental evolution of an RNA virus in wild birds: evidence for host-dependent impacts on population structure and competitive fitness.

    Science.gov (United States)

    Grubaugh, Nathan D; Smith, Darci R; Brackney, Doug E; Bosco-Lauth, Angela M; Fauver, Joseph R; Campbell, Corey L; Felix, Todd A; Romo, Hannah; Duggal, Nisha K; Dietrich, Elizabeth A; Eike, Tyler; Beane, Jennifer E; Bowen, Richard A; Black, William C; Brault, Aaron C; Ebel, Gregory D

    2015-05-01

    Within hosts, RNA viruses form populations that are genetically and phenotypically complex. Heterogeneity in RNA virus genomes arises due to error-prone replication and is reduced by stochastic and selective mechanisms that are incompletely understood. Defining how natural selection shapes RNA virus populations is critical because it can inform treatment paradigms and enhance control efforts. We allowed West Nile virus (WNV) to replicate in wild-caught American crows, house sparrows and American robins to assess how natural selection shapes RNA virus populations in ecologically relevant hosts that differ in susceptibility to virus-induced mortality. After five sequential passages in each bird species, we examined the phenotype and population diversity of WNV through fitness competition assays and next generation sequencing. We demonstrate that fitness gains occur in a species-specific manner, with the greatest replicative fitness gains in robin-passaged WNV and the least in WNV passaged in crows. Sequencing data revealed that intrahost WNV populations were strongly influenced by purifying selection and the overall complexity of the viral populations was similar among passaged hosts. However, the selective pressures that control WNV populations seem to be bird species-dependent. Specifically, crow-passaged WNV populations contained the most unique mutations (~1.7× more than sparrows, ~3.4× more than robins) and defective genomes (~1.4× greater than sparrows, ~2.7× greater than robins), but the lowest average mutation frequency (about equal to sparrows, ~2.6× lower than robins). Therefore, our data suggest that WNV replication in the most disease-susceptible bird species is positively associated with virus mutational tolerance, likely via complementation, and negatively associated with the strength of selection. These differences in genetic composition most likely have distinct phenotypic consequences for the virus populations. Taken together, these results

  13. Experimental evolution of an RNA virus in wild birds: evidence for host-dependent impacts on population structure and competitive fitness.

    Directory of Open Access Journals (Sweden)

    Nathan D Grubaugh

    2015-05-01

    Full Text Available Within hosts, RNA viruses form populations that are genetically and phenotypically complex. Heterogeneity in RNA virus genomes arises due to error-prone replication and is reduced by stochastic and selective mechanisms that are incompletely understood. Defining how natural selection shapes RNA virus populations is critical because it can inform treatment paradigms and enhance control efforts. We allowed West Nile virus (WNV to replicate in wild-caught American crows, house sparrows and American robins to assess how natural selection shapes RNA virus populations in ecologically relevant hosts that differ in susceptibility to virus-induced mortality. After five sequential passages in each bird species, we examined the phenotype and population diversity of WNV through fitness competition assays and next generation sequencing. We demonstrate that fitness gains occur in a species-specific manner, with the greatest replicative fitness gains in robin-passaged WNV and the least in WNV passaged in crows. Sequencing data revealed that intrahost WNV populations were strongly influenced by purifying selection and the overall complexity of the viral populations was similar among passaged hosts. However, the selective pressures that control WNV populations seem to be bird species-dependent. Specifically, crow-passaged WNV populations contained the most unique mutations (~1.7× more than sparrows, ~3.4× more than robins and defective genomes (~1.4× greater than sparrows, ~2.7× greater than robins, but the lowest average mutation frequency (about equal to sparrows, ~2.6× lower than robins. Therefore, our data suggest that WNV replication in the most disease-susceptible bird species is positively associated with virus mutational tolerance, likely via complementation, and negatively associated with the strength of selection. These differences in genetic composition most likely have distinct phenotypic consequences for the virus populations. Taken together

  14. Climate impacts on bird and plant communities from altered animal-plant interactions

    Science.gov (United States)

    Martin, Thomas E.; Maron, John L.

    2012-01-01

    The contribution of climate change to declining populations of organisms remains a question of outstanding concern. Much attention to declining populations has focused on how changing climate drives phenological mismatches between animals and their food. Effects of climate on plant communities may provide an alternative, but particularly powerful, influence on animal populations because plants provide their habitats. Here, we show that abundances of deciduous trees and associated songbirds have declined with decreasing snowfall over 22 years of study in montane Arizona, USA. We experimentally tested the hypothesis that declining snowfall indirectly influences plants and associated birds by allowing greater over-winter herbivory by elk (Cervus canadensis). We excluded elk from one of two paired snowmelt drainages (10 ha per drainage), and replicated this paired experiment across three distant canyons. Over six years, we reversed multi-decade declines in plant and bird populations by experimentally inhibiting heavy winter herbivory associated with declining snowfall. Moreover, predation rates on songbird nests decreased in exclosures, despite higher abundances of nest predators, demonstrating the over-riding importance of habitat quality to avian recruitment. Thus, our results suggest that climate impacts on plant–animal interactions can have forceful ramifying effects on plants, birds, and ecological interactions.

  15. Rate of Decline of the Oriental White-Backed Vulture Population in India Estimated from a Survey of Diclofenac Residues in Carcasses of Ungulates

    Science.gov (United States)

    Green, Rhys E.; Taggart, Mark A.; Senacha, Kalu Ram; Raghavan, Bindu; Pain, Deborah J.; Jhala, Yadvendradev; Cuthbert, Richard

    2007-01-01

    The non-steroidal anti-inflammatory drug diclofenac is a major cause of the rapid declines in the Indian subcontinent of three species of vultures endemic to South Asia. The drug causes kidney failure and death in vultures. Exposure probably arises through vultures feeding on carcasses of domesticated ungulates treated with the drug. However, before the study reported here, it had not been established from field surveys of ungulate carcasses that a sufficient proportion was contaminated to cause the observed declines. We surveyed diclofenac concentrations in samples of liver from carcasses of domesticated ungulates in India in 2004–2005. We estimated the concentration of diclofenac in tissues available to vultures, relative to that in liver, and the proportion of vultures killed after feeding on a carcass with a known level of contamination. We assessed the impact of this mortality on vulture population trend with a population model. We expected levels of diclofenac found in ungulate carcasses in 2004–2005 to cause oriental white-backed vulture population declines of 80–99% per year, depending upon the assumptions used in the model. This compares with an observed rate of decline, from road transect counts, of 48% per year in 2000–2003. The precision of the estimate based upon carcass surveys is low and the two types of estimate were not significantly different. Our analyses indicate that the level of diclofenac contamination found in carcasses of domesticated ungulates in 2004–2005 was sufficient to account for the observed rapid decline of the oriental white-backed vulture in India. The methods we describe could be used again to assess changes in the effect on vulture population trend of diclofenac and similar drugs. In this way, the effectiveness of the recent ban in India on the manufacture and importation of diclofenac for veterinary use could be monitored. PMID:17668064

  16. Pesticide residues in birds and mammals

    Science.gov (United States)

    Stickel, L.F.; Edwards, C.A.

    1973-01-01

    exposure to an organochlorine pesticide, the concentrations of residues in the different tissues are ordinarily directly correlated with each other. When the dosage is at lethal levels, or when stored residues are mobilised to lethal levels, the balanced relationship is disrupted. The concentrations of residues in the brain provide the most rigorous criteria for diagnosis of death due to these chemicals, and levels are generally similar across a wide range of species of birds and mammals. Residues in liver are closely correlated with recent dose, either from direct intake or from mobilisation from storage, and so reflect hazardous exposure. Residues in the whole carcass show the storage reserve, and so indicate the potential for adverse effects from lethal mobilisation or from the continuous slow mobilisation that occurs during the normal processes of metabolism and excretion. A synchronous, rapid, and widespread decline in weight and thickness of shells of eggs laid by many species of wild birds occurred in the late 1940's and has persisted. Birds of prey were primarily affected; exceptions apparently are the result of lesser exposure because of different food habits. Many species of fish-eating birds are also affected. Others, however, appear to be more resistant and to accumulate much higher residues before shell-thinning occurs. Seed-eating birds do not appear to have been generally affected; their exposure is ordinarily lower, but physiological factors also seem to be involved. A relationship between shell-thinning and population decline has been established for many species. In exceptional cases, such as the herring gull, persistent re-nesting and other population reactions have overcome adverse effects at the population level. The discovery of shell-thinning among natural populations, and the hypothesis that this thinning was related to the occurrence of organochlorine pesticides, stimulated experimental studies to determine wheth

  17. Impact of tooth loss on walking speed decline over time in older adults: a population-based cohort study.

    Science.gov (United States)

    Welmer, Anna-Karin; Rizzuto, Debora; Parker, Marti G; Xu, Weili

    2017-08-01

    Tooth loss has been linked to poor health such as chronic diseases and mobility limitations. Prospective evidence on the association between tooth loss and walking speed decline is however lacking. To examine the impact of tooth loss on walking speed over time and explore whether inflammation may account for this association. This study included 2695 persons aged 60 years and older, who were free from severe mobility limitation at baseline. Information on dental status was assessed through self-report during the nurse interview at baseline. Walking speed baseline and at 3- and 6-year follow-ups was assessed when participants walked at their usual pace. Covariates included age, sex, education, lifestyle-related factors, and chronic diseases. Blood samples were taken, and C-reactive protein (CRP) was tested. At baseline, 389 (13.1 %) participants had partial tooth loss and 204 (6.9 %) had complete tooth loss. Mixed-effects models showed that tooth loss was associated with a greater decline in walking speed over time after adjustment for lifestyle-related factors and chronic diseases (p = 0.001 for interaction between time and tooth loss on walking speed decline); however, when further adjusting for inflammation (CRP), the association was attenuated and no longer significant. Tooth loss was associated with an accelerated decline in walking speed in older adults. Inflammation may play a role in the association between tooth loss and walking speed decline.

  18. Multilocus sequence typing of Ornithobacterium rhinotracheale isolated from pigeons and birds of prey revealed new insights into its population structure

    Directory of Open Access Journals (Sweden)

    Susann Thieme

    2016-12-01

    The MLST results of ORT isolated from pigeons and birds of prey likely reflect evolutionary bacterial host adaptations but might also indicate a potential for interspecies transmission. Definite conclusions should be drawn carefully as so far a few strains from non-galliform birds were analyzed by MLST. By extending the number of ORT isolates and the range of potential avian hosts, the MLST database can provide a valuable resource in understanding transmission dynamics.

  19. Regular physical activity modifies smoking-related lung function decline and reduces risk of chronic obstructive pulmonary disease: a population-based cohort study

    DEFF Research Database (Denmark)

    Garcia-Aymerich, J; Lange, Peter; Benet, M

    2007-01-01

    RATIONALE: We have previously reported that regular physical activity reduces risk of chronic obstructive pulmonary disease (COPD) exacerbation. We hypothesized that higher levels of regular physical activity could reduce the risk of COPD by modifying smoking-related lung function decline....... OBJECTIVE: To estimate the longitudinal association between regular physical activity and FEV(1) and FVC decline and COPD risk. METHODS: A population-based sample (n = 6,790) was recruited and assessed with respect to physical activity, smoking, lung function, and other covariates, in Copenhagen in 1981......-1983, and followed until 1991-1994. Mean level of physical activity between baseline and follow-up was classified into "low," "moderate," and "high." FEV(1) and FVC decline rates were expressed as milliliters per year. COPD was defined as FEV(1)/FVC physical activity and FEV...

  20. Scrub-shrub bird habitat associations at multiple spatial scales in beaver meadows in Massachusetts

    Science.gov (United States)

    Chandler, R.B.; King, D.I.; DeStefano, S.

    2009-01-01

    Most scrub-shrub bird species are declining in the northeastern United States, and these declines are largely attributed to regional declines in habitat availability. American Beaver (Castor canadensis; hereafter “beaver”) populations have been increasing in the Northeast in recent decades, and beavers create scrub-shrub habitat through their dam-building and foraging activities. Few systematic studies have been conducted on the value of beaver-modified habitats for scrub-shrub birds, and these data are important for understanding habitat selection of scrub-shrub birds as well as for assessing regional habitat availability for these species. We conducted surveys in 37 beaver meadows in a 2,800-km2 study area in western Massachusetts during 2005 and 2006 to determine the extent to which these beaver-modified habitats are used by scrub-shrub birds, as well as the characteristics of beaver meadows most closely related to bird use. We modeled bird abundance in relation to microhabitat-, patch-, and landscape-context variables while adjusting for survey-specific covariates affecting detectability using N-mixture models. We found that scrub-shrub birds of regional conservation concern occupied these sites and that birds responded differently to microhabitat, patch, and landscape characteristics of beaver meadows. Generally, scrub-shrub birds increased in abundance along a gradient of increasing vegetation complexity, and three species were positively related to patch size. We conclude that these habitats can potentially play an important role in regional conservation of scrub-shrub birds and recommend that conservation priority be given to larger beaver meadows with diverse vegetation structure and composition.

  1. Screamy Bird

    DEFF Research Database (Denmark)

    Tarby, Sara; Cermak, Daniel

    2016-01-01

    Sara Tarby, Daniel Cermak-Sassenrath. Screamy Bird. Digital game. Kulturnatten 2016, Danish Science Ministry, Copenhagen, DK, Oct 14, 2016.......Sara Tarby, Daniel Cermak-Sassenrath. Screamy Bird. Digital game. Kulturnatten 2016, Danish Science Ministry, Copenhagen, DK, Oct 14, 2016....

  2. The recent decline of Montastraea annularis (complex coral populations in western Curaçao: a cause for concern?

    Directory of Open Access Journals (Sweden)

    A. W Bruckner

    2006-12-01

    Full Text Available Shallow leeward reefs off the western end of Curaçao are dominated by extensive populations of M. annularis (complex. These species are larger in size (mean= 66 cm diameter than all other species, with few small colonies (10 cm observed within transects, and most exhibited low levels of partial mortality (mean= 22.5%. These species were less abundant (38% of all colonies in 2005. Partial mortality among live colonies of M. annularis and M. faveolata increased by 85% (mean = 42% partial mortality and numerous dead colonies of M. faveolata and M. annularis were observed; M. franksi colonies were generally in excellent condition (14% partial tissue mortality. A high prevalence of coral diseases (3-30% was documented among M. annularis and M. faveolata, while all other species were less frequently affected. Yellow band disease (YBD emerged shortly after the 1995 bleaching event, and rapidly spread throughout all depths, with the highest prevalence between 1997-1999. YBD caused slow rates of mortality (=1 cm/month, but multiple focal lesions appeared on individual colonies, and these progressively radiated outward as they killed the colonies. By 2005, 44% of the tagged corals were dead; the remainder exhibited active YBD infections (21% or were in remission (31.6% but were missing on average >90% of their tissue. Although the incidence of YBD has declined since 2000, white plague (WP prevalence was unusually high (4-12% in 2001 and 2005, with affected colonies exhibiting recent mortality of up to 70%. Dead Montastraea spp. surfaces are being colonized by other corals, including poritids, agaricids, and other faviids, while recruits of M. annularis (complex are absent. If diseases and other biotic stressors persist on these reefs, M. annularis and M. faveolata populations may undergo a decline similar to that observed in the 1980s among Caribbean acroporids. Rev. Biol. Trop. 54 (Suppl. 3: 45- 58. Epub 2007 Jan. 15.Los arrecifes someros a sotavento

  3. Neighborhood context and cognitive decline in older Mexican Americans: results from the Hispanic Established Populations for Epidemiologic Studies of the Elderly.

    Science.gov (United States)

    Sheffield, Kristin M; Peek, M Kristen

    2009-05-01

    In previous research on cognitive decline among older adults, investigators have not considered the potential impact of contextual variables, such as neighborhood-level conditions. In the present investigation, the authors examined the association between 2 neighborhood-context variables-socioeconomic status and percentage of Mexican-American residents-and individual-level cognitive function over a 5-year follow-up period (1993-1998). Data were obtained from the Hispanic Established Populations for Epidemiologic Studies of the Elderly, a longitudinal study of community-dwelling older Mexican Americans (n = 3,050) residing in the southwestern United States. Individual records were linked with 1990 US Census tract data, which provided information on neighborhood characteristics. Hierarchical linear growth-curve models and hierarchical logistic models were used to examine relations between individual- and neighborhood-level variables and the rate and incidence of cognitive decline. Results showed that baseline cognitive function and rates of cognitive decline varied significantly across US Census tracts. Respondents living in economically disadvantaged neighborhoods experienced significantly faster rates of cognitive decline than those in more advantaged neighborhoods. Odds of incident cognitive decline decreased as a function of neighborhood percentage of Mexican-American residents and increased with neighborhood economic disadvantage. The authors conclude that neighborhood context is associated with late-life cognitive function and that the effects are independent of individual-level risk factors.

  4. Destructive attraction : factors that influence hunting pressure on the Blue Bird-of-paradise Paradisaea rudolphi

    NARCIS (Netherlands)

    Bergh, van den M.; Kusters, K.; Dietz, J A.

    2013-01-01

    The Blue Bird-of-paradise Paradisaea rudolphi (BBOP) is a globally threatened species restricted to the montane rainforest of Papua New Guinea (PNG). Local inhabitants hunt the BBOP for its feathers, which is one of the main reasons for its population decline. The feathers are used for both

  5. Bird list of San Bernardino Ranch in Agua Prieta, Sonora, Mexico

    Science.gov (United States)

    Melinda Cardenas-Garcia; Monica C. Olguin-Villa

    2013-01-01

    Interest and investigation of birds has been increasing over the last decades due to the loss of their habitats, and declination and fragmentation of their populations. San Bernardino Ranch is located in the desert grassland region of northeastern Sonora, México. Over the last decade, restoration efforts have tried to address the effects of long deteriorating economic...

  6. Culturable bacterial populations associated with ectomycorrhizae of Norway spruce stands with different degrees of decline in the Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Avidano, L.; Rinaldi, M.; Gindro, R.; Cudlín, Pavel; Martinotti, M G.; Fracchia, L.

    2010-01-01

    Roč. 56, č. 1 (2010), s. 52-64 ISSN 0008-4166 Institutional research plan: CEZ:AV0Z60870520 Keywords : Ectomycorrhizae * Norway spruce * forest decline Subject RIV: EE - Microbiology, Virology Impact factor: 1.235, year: 2010

  7. The Nordic Prudent Diet Reduces Risk of Cognitive Decline in the Swedish Older Adults: A Population-Based Cohort Study

    Directory of Open Access Journals (Sweden)

    Behnaz Shakersain

    2018-02-01

    Full Text Available Appropriate dietary pattern for preserving cognitive function in northern Europe remains unknown. We aimed to identify a Nordic dietary pattern index associated with slower cognitive decline compared to the Mediterranean-DASH Intervention for Neurodegenerative Delay, Mediterranean Diet, Dietary Approaches to Stop Hypertension, and Baltic Sea Diet indices. A total of 2223 dementia-free adults aged ≥60 were followed for 6 years. Mini-Mental State Examination was administrated at baseline and follow-ups. Dietary intake was assessed by 98-item food frequency questionnaire, and the Nordic Prudent Dietary Pattern (NPDP was identified. Data were analysed using mixed-effects and parametric survival models and receiver operating characteristic curves with adjustment for potential confounders. Moderate (β = 0.139, 95% CI 0.077−0.201 and high adherence (β = 0.238, 95% CI 0.175−0.300 to NPDP were associated with less cognitive decline compared to other four indices. High adherence to NPDP was also associated with the lowest risk of MMSE decline to ≤24 (HR = 0.176, 95% CI 0.080−0.386 and had the greatest ability to predict such decline (area under the curve = 0.70. Moderate-to-high adherence to the NPDP may predict a better-preserved cognitive function among older adults in Nordic countries. Regional dietary habits should be considered in developing dietary guidelines for the prevention of cognitive impairment and dementia.

  8. The catastrophic decline of the Sumatran rhino (Dicerorhinus sumatrensis harrissoni in Sabah: Historic exploitation, reduced female reproductive performance and population viability

    Directory of Open Access Journals (Sweden)

    P. Kretzschmar

    2016-04-01

    Full Text Available The reasons for catastrophic declines of Sumatran rhinos are far from clear and data necessary to improve decisions for conservation management are often lacking. We reviewed literature and assembled a comprehensive data set on surveys of the Sumatran rhino subspecies (Dicerorhinus sumatrensis harrissoni in the Malaysian state of Sabah on Borneo to chart the historical development of the population in Sabah and its exploitation until the present day. We fitted resource selection functions to identify habitat features preferred by a remnant population of rhinos living in the Tabin Wildlife Reserve in Sabah, and ran a series of population viability analyses (PVAs to extract the key demographic parameters most likely to affect population dynamics. We show that as preferred habitat, the individuals in the reserve were most likely encountered in elevated areas away from roads, in close distance to mud-volcanoes, with a low presence of human trespassers and a wallow on site, and within a neighbourhood of dense forest and grassland patches preferably on Fluvisols and Acrisols. Our population viability analyses identified the percentage of breeding females and female lifetime reproductive period as the crucial parameters driving population dynamics, in combination with total protection even moderate improvements could elevate population viability substantially. The analysis also indicates that unrestrained hunting between 1930 and 1950 drastically reduced the historical rhino population in Sabah and that the remnant population could be rescued by combining the effort of total protection and stimulation of breeding activity. Based on our results, we recommend to translocate isolated reproductively healthy individuals to protected locations and to undertake measures to maximise conceptions, or running state-of-the-art reproductive management with assisted reproduction techniques. Our study demonstrates that a judicious combination of techniques can do

  9. Forest fragmentation and its effects on birds

    Science.gov (United States)

    Robbins, C.S.; Johnson, James E.

    1988-01-01

    Fragmentation of forest land, whether by suburban development, highways, transmission lines, or poorly planned cutting regimes, seriously affects reproduction by the large numbers of obligate forest interior birds. Many of our warblers, vireos, thrushes, tanagers, and flycatchers are highly migratory insectivorous birds that spend more than half the year in the neotropics, but migrate north to the United States and Canada to rear their young. These tropical visitors are especially vulnerable to predation and cowbird parasitism and are unable to maintain their populations within 100-200 m of forest edge. Habitats for these declining species can be provided by managing forest lands in large blocks so as to maintain at all times extensive contiguous areas of successional stages as well as of mature forest. Avoiding scattered small cuts will also help by reducing edge, road construction, and other disturbance.

  10. Brain Amyloid Deposition and Longitudinal Cognitive Decline in Nondemented Older Subjects: Results from a Multi-Ethnic Population.

    Directory of Open Access Journals (Sweden)

    Yian Gu

    Full Text Available We aimed to whether the abnormally high amyloid-β (Aβ level in the brain among apparently healthy elders is related with subtle cognitive deficits and/or accelerated cognitive decline.A total of 116 dementia-free participants (mean age 84.5 years of the Washington Heights Inwood Columbia Aging Project completed 18F-Florbetaben PET imaging. Positive or negative cerebral Aβ deposition was assessed visually. Quantitative cerebral Aβ burden was calculated as the standardized uptake value ratio in pre-established regions of interest using cerebellar cortex as the reference region. Cognition was determined using a neuropsychological battery and selected tests scores were combined into four composite scores (memory, language, executive/speed, and visuospatial using exploratory factor analysis. We examined the relationship between cerebral Aβ level and longitudinal cognition change up to 20 years before the PET scan using latent growth curve models, controlling for age, education, ethnicity, and Apolipoprotein E (APOE genotype.Positive reading of Aβ was found in 41 of 116 (35% individuals. Cognitive scores at scan time was not related with Aβ. All cognitive scores declined over time. Aβ positive reading (B = -0.034, p = 0.02 and higher Aβ burden in temporal region (B = -0.080, p = 0.02 were associated with faster decline in executive/speed. Stratified analyses showed that higher Aβ deposition was associated with faster longitudinal declines in mean cognition, language, and executive/speed in African-Americans or in APOE ε4 carriers, and with faster memory decline in APOE ε4 carriers. The associations remained significant after excluding mild cognitive impairment participants.High Aβ deposition in healthy elders was associated with decline in executive/speed in the decade before neuroimaging, and the association was observed primarily in African-Americans and APOE ε4 carriers. Our results suggest that measuring cerebral Aβ may give us

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

    Science.gov (United States)

    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

  12. Health status of seabirds and coastal birds found at the German North Sea coast

    Directory of Open Access Journals (Sweden)

    Siebert Ursula

    2012-07-01

    Full Text Available Abstract Background Systematic pathological investigations to assess the health status of seabirds and coastal birds in Germany were performed. The investigation was conducted to obtain data on possible causes of decline in seabird and coastal bird populations. Methods 48 individuals of 11 different species of seabirds and coastal birds were collected by the stranding network along the entire German North Sea coast from 1997 to 2008, including mainly waders such as Eurasian oystercatchers (Haematopus ostralegus and red knots (Calidris canutus as well as seabirds such as northern fulmars (Fulmaris glacialis and common scoters (Melanitta nigra. For most birds (n = 31 found dead along the shore no obvious cause of death was evident, while 17 individuals were killed by collisions with lighthouses. Results Overall, the nutritional status of the investigated birds was very poor, and the body mass in most cases was significantly lower compared to masses of living birds caught during the same periods of the year. This is partly linked to chronic parasitic or bacterial infections in different organs or to septicaemia. In some cases infections with zoonotic tuberculosis caused by Mycobacterium spp. were found. Avian influenza was not found in any of the collected birds. Conclusion The presented data contribute to the evaluation of the health status of birds in the German North Sea. Moreover, they present an important tool for the assessment of potential pathogens with an impact on the health status of seabirds and coastal birds.

  13. Health status of seabirds and coastal birds found at the German North Sea coast.

    Science.gov (United States)

    Siebert, Ursula; Schwemmer, Philipp; Guse, Nils; Harder, Timm; Garthe, Stefan; Prenger-Berninghoff, Ellen; Wohlsein, Peter

    2012-07-19

    Systematic pathological investigations to assess the health status of seabirds and coastal birds in Germany were performed. The investigation was conducted to obtain data on possible causes of decline in seabird and coastal bird populations. 48 individuals of 11 different species of seabirds and coastal birds were collected by the stranding network along the entire German North Sea coast from 1997 to 2008, including mainly waders such as Eurasian oystercatchers (Haematopus ostralegus) and red knots (Calidris canutus) as well as seabirds such as northern fulmars (Fulmaris glacialis) and common scoters (Melanitta nigra).For most birds (n = 31) found dead along the shore no obvious cause of death was evident, while 17 individuals were killed by collisions with lighthouses. Overall, the nutritional status of the investigated birds was very poor, and the body mass in most cases was significantly lower compared to masses of living birds caught during the same periods of the year. This is partly linked to chronic parasitic or bacterial infections in different organs or to septicaemia. In some cases infections with zoonotic tuberculosis caused by Mycobacterium spp. were found. Avian influenza was not found in any of the collected birds. The presented data contribute to the evaluation of the health status of birds in the German North Sea. Moreover, they present an important tool for the assessment of potential pathogens with an impact on the health status of seabirds and coastal birds.

  14. Social Participation and the Prevention of Decline in Effectance among Community-Dwelling Elderly: A Population-Based Cohort Study.

    Directory of Open Access Journals (Sweden)

    Kimiko Tomioka

    Full Text Available We examined the association between a decline in effectance and social participation (SP from the perspective of the number and the type of SP in a prospective cohort study.Included in this analysis were community-dwelling elderly aged ≥ 65 without dependency on the basic activities of daily living and reporting a perfect baseline effectance score (n = 4,588; mean age 72.8 ± 5.7. SP was categorized into 5 types: neighborhood associations, hobby groups, local event groups, senior citizen clubs, and volunteer groups. Effectance was evaluated using the Tokyo Metropolitan Institute of Gerontology Index of Competence. Using logistic regression analysis, odds ratio (OR and a 95% confidence interval (CI for a decline in effectance were calculated. Age, family, BMI, pensions, medical history, medications, alcohol, smoking, cognitive function, depression, social support, ADL, and IADL were used as covariates.During the 3-year follow-up, 17.8% of eligible participants reported a decline in effectance. After adjustment for covariates, participation in various groups was associated with the preservation of effectance for both genders. Regarding the type of SP, among females, participation in neighborhood associations (OR: 0.62, 95%CI: 0.48-0.81, hobby groups (0.58, 0.43-0.77, local event groups (0.63, 0.47-0.86, and volunteer groups (0.53, 0.35-0.82 was inversely associated with a decline in effectance. Among males, the beneficial effect was more likely limited to hobby groups (0.59, 0.43-0.81 and volunteer groups (0.57, 0.39-0.83.Our results suggest that participation in a variety of social groups is effective for maintenance of older people's effectance, while the beneficial effect of each type of SP on effectance is stronger for females than for males. Recommending community-dwelling elderly to participate in social groups appropriate for their gender may be effective for successful aging.

  15. Declining prevalence of pulmonary paragonimiasis following treatment & community education in a remote tribal population of Arunachal Pradesh, India.

    Science.gov (United States)

    Narain, Kanwar; Devi, K Rekha; Bhattacharya, S; Negmu, K; Rajguru, S K; Mahanta, Jagadish

    2015-05-01

    In India, human pulmonary paragonimiasis is an important public health problem in the northeastern (NE) region. In 2005 we reported a hyperendemic focus of paragonimiasis in a remote tribal village in the hills of Changlang district in Arunachal Pradesh. The community was made aware of the disease and all active cases were treated. This study was aimed to assess the decline in the prevelance of paragonimiasis in the same area after a re-survey done in 2011 after a gap of six years. Re-surveys were carried to determine the reduction in the prevalence of paragonimiasis. Community education was given to the villagers to raise their awareness about paragonimiasis. A total of 624 individuals including 301 children (age 15 yr) were included in the study. Sputum and stool samples were examined for eggs of lung flukes. Serum samples were screened for IgG antibodies against lung fluke antigen by ELISA. A significant (P 31 yr, the decline in prevalence was from 15.3 to 3.7 per cent. Gender-wise analysis revealed that the decline in ELISA positivity was similar in both genders and fell down from 33.9 to 11.5 per cent in males and from 29.8 to 10.7 per cent in females. Similarly, there was a significant decline rate in egg positivity also. The strategy of hotspot targeted active paragonimiasis case detection and treatment of infected cases together with community education appears to be feasible methods to achieve control of paragonimiasis in this region.

  16. Two Different Populations within the Healthy Elderly: Lack of Conflict Detection in Those at Risk of Cognitive Decline

    Directory of Open Access Journals (Sweden)

    Sergio M. Sánchez-Moguel

    2018-01-01

    Full Text Available During healthy aging, inhibitory processing is affected at the sensorial, perceptual, and cognitive levels. The assessment of event-related potentials (ERPs during the Stroop task has been used to study age-related decline in the efficiency of inhibitory processes. Studies using ERPs have found that the P300 amplitude increases and the N500 amplitude is attenuated in healthy elderly adults compared to those in young adults. On the other hand, it has been reported that theta excess in resting EEG with eyes closed is a good predictor of cognitive decline during aging 7 years later, while a normal EEG increases the probability of not developing cognitive decline. The behavioral and ERP responses during a Counting-Stroop task were compared between 22 healthy elderly subjects with normal EEG (Normal-EEG group and 22 healthy elderly subjects with an excess of EEG theta activity (Theta-EEG group. Behaviorally, the Normal-EEG group showed a higher behavioral interference effect than the Theta-EEG group. ERP patterns were different between the groups, and two facts are highlighted: (a the P300 amplitude was higher in the Theta-EEG group, with both groups showing a P300 effect in almost all electrodes, and (b the Theta-EEG group did not show an N500 effect. These results suggest that the diminishment in inhibitory control observed in the Theta-EEG group may be compensated by different processes in earlier stages, which would allow them to perform the task with similar efficiency to that of participants with a normal EEG. This study is the first to show that healthy elderly subjects with an excess of theta EEG activity not only are at risk of developing cognitive decline but already have a cognitive impairment.

  17. A spatial analysis of population dynamics and climate change in Africa: potential vulnerability hot spots emerge where precipitation declines and demographic pressures coincide

    Science.gov (United States)

    López-Carr, David; Pricope, Narcisa G.; Aukema, Juliann E.; Jankowska, Marta M.; Funk, Christopher C.; Husak, Gregory J.; Michaelsen, Joel C.

    2014-01-01

    We present an integrative measure of exposure and sensitivity components of vulnerability to climatic and demographic change for the African continent in order to identify “hot spots” of high potential population vulnerability. Getis-Ord Gi* spatial clustering analyses reveal statistically significant locations of spatio-temporal precipitation decline coinciding with high population density and increase. Statistically significant areas are evident, particularly across central, southern, and eastern Africa. The highly populated Lake Victoria basin emerges as a particularly salient hot spot. People located in the regions highlighted in this analysis suffer exceptionally high exposure to negative climate change impacts (as populations increase on lands with decreasing rainfall). Results may help inform further hot spot mapping and related research on demographic vulnerabilities to climate change. Results may also inform more suitable geographical targeting of policy interventions across the continent.

  18. Conservation Action Based on Threatened Species Capture Taxonomic and Phylogenetic Richness in Breeding and Wintering Populations of Central Asian Birds

    Science.gov (United States)

    Schweizer, Manuel; Ayé, Raffael; Kashkarov, Roman; Roth, Tobias

    2014-01-01

    Although phylogenetic diversity has been suggested to be relevant from a conservation point of view, its role is still limited in applied nature conservation. Recently, the practice of investing conservation resources based on threatened species was identified as a reason for the slow integration of phylogenetic diversity in nature conservation planning. One of the main arguments is based on the observation that threatened species are not evenly distributed over the phylogenetic tree. However this argument seems to dismiss the fact that conservation action is a spatially explicit process, and even if threatened species are not evenly distributed over the phylogenetic tree, the occurrence of threatened species could still indicate areas with above average phylogenetic diversity and consequently could protect phylogenetic diversity. Here we aim to study the selection of important bird areas in Central Asia, which were nominated largely based on the presence of threatened bird species. We show that although threatened species occurring in Central Asia do not capture phylogenetically more distinct species than expected by chance, the current spatially explicit conservation approach of selecting important bird areas covers above average taxonomic and phylogenetic diversity of breeding and wintering birds. We conclude that the spatially explicit processes of conservation actions need to be considered in the current discussion of whether new prioritization methods are needed to complement conservation action based on threatened species. PMID:25337861

  19. Conservation action based on threatened species capture taxonomic and phylogenetic richness in breeding and wintering populations of Central Asian birds.

    Directory of Open Access Journals (Sweden)

    Manuel Schweizer

    Full Text Available Although phylogenetic diversity has been suggested to be relevant from a conservation point of view, its role is still limited in applied nature conservation. Recently, the practice of investing conservation resources based on threatened species was identified as a reason for the slow integration of phylogenetic diversity in nature conservation planning. One of the main arguments is based on the observation that threatened species are not evenly distributed over the phylogenetic tree. However this argument seems to dismiss the fact that conservation action is a spatially explicit process, and even if threatened species are not evenly distributed over the phylogenetic tree, the occurrence of threatened species could still indicate areas with above average phylogenetic diversity and consequently could protect phylogenetic diversity. Here we aim to study the selection of important bird areas in Central Asia, which were nominated largely based on the presence of threatened bird species. We show that although threatened species occurring in Central Asia do not capture phylogenetically more distinct species than expected by chance, the current spatially explicit conservation approach of selecting important bird areas covers above average taxonomic and phylogenetic diversity of breeding and wintering birds. We conclude that the spatially explicit processes of conservation actions need to be considered in the current discussion of whether new prioritization methods are needed to complement conservation action based on threatened species.

  20. Covariance of paternity and sex with laying order explains male bias in extra-pair offspring in a wild bird population

    NARCIS (Netherlands)

    Vedder, O.; Magrath, M.J.L.; van der Velde, Marco; Komdeur, J.

    2013-01-01

    It has been hypothesized that parents increase their fitness by biasing the sex ratio of extra-pair offspring (EPO) towards males. Here, we report a male bias among EPO in a wild population of blue tits (Cyanistes caeruleus). This resulted from a decline in both the proportion of males and EPO over

  1. Failure to Respond to Food Resource Decline Has Catastrophic Consequences for Koalas in a High-Density Population in Southern Australia.

    Directory of Open Access Journals (Sweden)

    Desley A Whisson

    Full Text Available Understanding the ability of koalas to respond to changes in their environment is critical for conservation of the species and their habitat. We monitored the behavioural response of koalas to declining food resources in manna gum (Eucalyptus viminalis woodland at Cape Otway, Victoria, Australia, from September 2011 to November 2013. Over this period, koala population density increased from 10.1 to 18.4 koalas.ha-1. As a result of the high browsing pressure of this population, manna gum canopy condition declined with 71.4% manna gum being completely or highly defoliated in September 2013. Despite declining food resources, radio collared koalas (N = 30 exhibited high fidelity to small ranges (0.4-1.2 ha. When trees became severely defoliated in September 2013, koalas moved relatively short distances from their former ranges (mean predicted change in range centroid = 144 m and remained in areas of 0.9 to 1.0 ha. This was despite the high connectivity of most manna gum woodland, and close proximity of the study site (< 3 km to the contiguous mixed forest of the Great Otway National Park. Limited movement had catastrophic consequences for koalas with 71% (15/21 of radio collared koalas dying from starvation or being euthanased due to their poor condition between September and November 2013.

  2. Effects of Cougar Predation and Nutrition on Mule Deer Population Declines in the IM Province of the Columbia Basin, Annual Report 2002-2003.

    Energy Technology Data Exchange (ETDEWEB)

    Wielgus, Robert; Shipley, Lisa; Myers, Woodrow

    2003-09-01

    Construction of the Grand Coulee and Chief Joseph dams has resulted in inundation and loss of 29,125 total habitat units for mule deer and irrigation agriculture in many parts the Intermountain Province (IM) of the Columbia Basin. Mule deer in the Shrub-Steppe are ranked high priority target species for mitigation and management and are declining in most portions of the sub basins of the IM. Reasons for the decline are unknown but believed to be related to habitat changes resulting from dams and irrigation agriculture. White-tailed deer are believed to be increasing throughout the basin because of habitat changes brought about by the dams and irrigation agriculture. Recent research (1997-2000) in the NE IM and adjacent Canadian portions of the Columbia Basin (conducted by this author and funded by the Columbia Basin Fish & Wildlife Compensation Program B.C.), suggest that the increasing white-tailed deer populations (because of dams and irrigation agriculture) are resulting in increased predation by cougars on mule deer (apparent competition or alternate prey hypothesis). The apparent competition hypothesis predicts that as alternate prey (white-tailed deer) densities increase, so do densities of predators, resulting in increased incidental predation on sympatric native prey (mule deer). Apparent competition can result in population declines and even extirpation of native prey in some cases. Such a phenomenon may account for declines of mule deer in the IM and throughout arid and semi-arid West where irrigation agriculture is practiced. We will test the apparent competition hypothesis by conducting a controlled, replicated 'press' experiment in at least 2 treatment and 2 control areas of the IM sub basins by reducing densities of white-tailed deer and observing any changes in cougar predation on mule deer. Deer densities will be monitored by WADFW personnel using annual aerial surveys and/or other trend indices. Predation rates and population growth rates

  3. Effects of Cougar Predation and Nutrition on Mule Deer Population Declines in the Intermountain Province of the Columbia Basin, 2001-2002 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Wielgus, Robert B.; Shipley, Lisa

    2002-07-01

    Construction of the Grand Coulee and Chief Joseph dams has resulted in inundation and loss of 29,125 total habitat units for mule deer and irrigation agriculture in many parts the Intermountain Province (IM) of the Columbia Basin. Mule deer in the Shrub-Steppe are ranked high priority target species for mitigation and management and are declining in most portions of the subbasins of the IM. Reasons for the decline are unknown but believed to be related to habitat changes resulting from dams and irrigation agriculture. White-tailed deer are not ranked as target species and are believed to be increasing throughout the basin because of habitat changes brought about by the dams and irrigation agriculture. Recent research (1997-2000) in the NE IM and adjacent Canadian portions of the Columbia Basin (conducted by this author and funded by the Columbia Basin Fish & Wildlife Compensation Program B.C.), suggest that the increasing white-tailed deer populations (because of dams and irrigation agriculture) are resulting in increased predation by cougars on mule deer (apparent competition or alternate prey hypothesis). The apparent competition hypothesis predicts that as alternate prey (white-tailed deer) densities increase, so do densities of predators, resulting in increased incidental predation on sympatric native prey (mule deer). Apparent competition can result in population declines and even extirpation of native prey in some cases. Such a phenomenon may account for declines of mule deer in the IM and throughout arid and semi-arid West where irrigation agriculture is practiced. We will test the apparent competition hypothesis by conducting a controlled, replicated ''press'' experiment in at least 2 treatment and 2 control areas of the IM subbasins by reducing densities of white-tailed deer and observing any changes in cougar predation on mule deer. Deer densities will be monitored by WADFW personnel using annual aerial surveys and/or other trend

  4. Re-examining mortality sources and population trends in a declining seabird: using Bayesian methods to incorporate existing information and new data.

    Directory of Open Access Journals (Sweden)

    Tim Reid

    Full Text Available The population of flesh-footed shearwaters (Puffinus carneipes breeding on Lord Howe Island was shown to be declining from the 1970's to the early 2000's. This was attributed to destruction of breeding habitat and fisheries mortality in the Australian Eastern Tuna and Billfish Fishery. Recent evidence suggests these impacts have ceased; presumably leading to population recovery. We used Bayesian statistical methods to combine data from the literature with more recent, but incomplete, field data to estimate population parameters and trends. This approach easily accounts for sources of variation and uncertainty while formally incorporating data and variation from different sources into the estimate. There is a 70% probability that the flesh-footed shearwater population on Lord Howe continued to decline during 2003-2009, and a number of possible reasons for this are suggested. During the breeding season, road-based mortality of adults on Lord Howe Island is likely to result in reduced adult survival and there is evidence that breeding success is negatively impacted by marine debris. Interactions with fisheries on flesh-footed shearwater winter grounds should be further investigated.

  5. Looking beyond rare species as umbrella species: Northern Bobwhites (Colinus virginianus) and conservation of grassland and shrubland birds

    Science.gov (United States)

    Crosby, Andrew D.; Elmore, R.D.; Leslie,, David M.; Will, Rodney E.

    2015-01-01

    Changes in land use and land cover throughout the eastern half of North America have caused substantial declines in populations of birds that rely on grassland and shrubland vegetation types, including socially and economically important game birds such as the Northern Bobwhite (Colinus virginianus; hereafter bobwhites). As much attention is focused on habitat management and restoration for bobwhites, they may act as an umbrella species for other bird species with similar habitat requirements. We quantified the relationship of bobwhites to the overall bird community and evaluated the potential for bobwhites to act as an umbrella species for grassland and shrubland birds. We monitored bobwhite presence and bird community composition within 31 sample units on selected private lands in the south-central United States from 2009 to 2011. Bobwhites were strongly associated with other grassland and shrubland birds and were a significant positive predictor for 9 species. Seven of these, including Bell's Vireo (Vireo bell), Dicksissel (Spiza americana), and Grasshopper Sparrow (Ammodramus savannarum), are listed as species of conservation concern. Species richness and occupancy probability of grassland and shrubland birds were higher relative to the overall bird community in sample units occupied by bobwhites. Our results show that bobwhites can act as an umbrella species for grassland and shrubland birds, although the specific species in any given situation will depend on region and management objectives. These results suggest that efficiency in conservation funding can be increased by using public interest in popular game species to leverage resources to meet multiple conservation objectives.

  6. Declining incidence of candidemia and the shifting epidemiology of Candida resistance in two US metropolitan areas, 2008-2013: results from population-based surveillance.

    Science.gov (United States)

    Cleveland, Angela Ahlquist; Harrison, Lee H; Farley, Monica M; Hollick, Rosemary; Stein, Betsy; Chiller, Tom M; Lockhart, Shawn R; Park, Benjamin J

    2015-01-01

    Recent reports have demonstrated a decline in bacterial bloodstream infections (BSIs) following adherence to central line insertion practices; however, declines have been less evident for BSIs due to Candida species. We conducted active, population-based laboratory surveillance for candidemia in metropolitan Atlanta, GA and Baltimore, MD over a 5-year period. We calculated annual candidemia incidence and antifungal drug resistance rates. We identified 3,848 candidemia cases from 2008-2013. Compared with 2008, candidemia incidence per 100,000 person-years decreased significantly by 2013 in both locations (GA: 14.1 to 9.5, pcandidemia over a five-year period, and increases in echinocandin-resistant and MDR Candida. Efforts to strengthen infection control practices may be preventing candidemia among high-risk patients. Further surveillance for resistant Candida is warranted.

  7. Declining Incidence of Candidemia and the Shifting Epidemiology of Candida Resistance in Two US Metropolitan Areas, 2008–2013: Results from Population-Based Surveillance

    Science.gov (United States)

    Cleveland, Angela Ahlquist; Harrison, Lee H.; Farley, Monica M.; Hollick, Rosemary; Stein, Betsy; Chiller, Tom M.; Lockhart, Shawn R.; Park, Benjamin J.

    2015-01-01

    Background Recent reports have demonstrated a decline in bacterial bloodstream infections (BSIs) following adherence to central line insertion practices; however, declines have been less evident for BSIs due to Candida species. Methods We conducted active, population-based laboratory surveillance for candidemia in metropolitan Atlanta, GA and Baltimore, MD over a 5-year period. We calculated annual candidemia incidence and antifungal drug resistance rates. Results We identified 3,848 candidemia cases from 2008–2013. Compared with 2008, candidemia incidence per 100,000 person-years decreased significantly by 2013 in both locations (GA: 14.1 to 9.5, pcandidemia over a five-year period, and increases in echinocandin-resistant and MDR Candida. Efforts to strengthen infection control practices may be preventing candidemia among high-risk patients. Further surveillance for resistant Candida is warranted. PMID:25822249

  8. Data Preparation for West Nile Virus Agent-Based Modelling: Protocol for Processing Bird Population Estimates and Incorporating ArcMap in AnyLogic.

    Science.gov (United States)

    Nasrinpour, Hamid Reza; Reimer, Alexander A; Friesen, Marcia R; McLeod, Robert D

    2017-07-17

    West Nile Virus (WNV) was first isolated in 1937. Since the 1950s, many outbreaks have occurred in various countries. The first appearance of infected birds in Manitoba, Canada was in 2002. This paper describes the data preparation phase of setting up a geographic information system (GIS) simulation environment for WNV Agent-Based Modelling in Manitoba. The main technology used in this protocol is based on AnyLogic and ArcGIS software. A diverse variety of topics and techniques regarding the data collection phase are presented, as modelling WNV has many disparate attributes, including landscape and weather impacts on mosquito population dynamics and birds' roosting locations, population count, and movement patterns. Different maps were combined to create a grid land cover map of Manitoba, Canada in a shapefile format compatible with AnyLogic, in order to modulate mosquito parameters. A significant amount of data regarding 152 bird species, along with their population estimates and locations in Manitoba, were gathered and assembled. Municipality shapefile maps were converted to built-in AnyLogic GIS regions for better compatibility with census data and initial placement of human agents. Accessing shapefiles and their databases in AnyLogic are also discussed. AnyLogic simulation software in combination with Esri ArcGIS provides a powerful toolbox for developers and modellers to simulate almost any GIS-based environment or process. This research should be useful to others working on a variety of mosquito-borne diseases (eg, Zika, dengue, and chikungunya) by demonstrating the importance of data relating to Manitoba and/or introducing procedures to compile such data. ©Hamid Reza Nasrinpour, Alexander A Reimer, Marcia R Friesen, Robert D McLeod. Originally published in JMIR Research Protocols (http://www.researchprotocols.org), 17.07.2017.

  9. Ecosystem Scale Declines in Elk Recruitment and Population Growth with Wolf Colonization: A Before-After-Control-Impact Approach

    OpenAIRE

    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 ...

  10. Host-seeking efficiency can explain population dynamics of the tsetse fly Glossina morsitans morsitans in response to host density decline.

    Science.gov (United States)

    Lord, Jennifer S; Mthombothi, Zinhle; Lagat, Vitalis K; Atuhaire, Fatumah; Hargrove, John W

    2017-07-01

    Females of all blood-feeding arthropod vectors must find and feed on a host in order to produce offspring. For tsetse-vectors of the trypanosomes that cause human and animal African trypanosomiasis-the problem is more extreme, since both sexes feed solely on blood. Host location is thus essential both for survival and reproduction. Host population density should therefore be an important driver of population dynamics for haematophagous insects, and particularly for tsetse, but the role of host density is poorly understood. We investigate the issue using data on changes in numbers of tsetse (Glossina morsitans morsitans Westwood) caught during a host elimination experiment in Zimbabwe in the 1960s. During the experiment, numbers of flies caught declined by 95%. We aimed to assess whether models including starvation-dependent mortality could explain observed changes in tsetse numbers as host density declined. An ordinary differential equation model, including starvation-dependent mortality, captured the initial dynamics of the observed tsetse population. However, whereas small numbers of tsetse were caught throughout the host elimination exercise, the modelled population went extinct. Results of a spatially explicit agent-based model suggest that this discrepancy could be explained by immigration of tsetse into the experimental plot. Variation in host density, as a result of natural and anthropogenic factors, may influence tsetse population dynamics in space and time. This has implications for Trypanosoma brucei rhodesiense transmission. Increased tsetse mortality as a consequence of low host density may decrease trypanosome transmission, but hungrier flies may be more inclined to bite humans, thereby increasing the risk of transmission to humans. Our model provides a way of exploring the role of host density on tsetse population dynamics and could be incorporated into models of trypanosome transmission dynamics to better understand how spatio-temporal variation in

  11. Host-seeking efficiency can explain population dynamics of the tsetse fly Glossina morsitans morsitans in response to host density decline.

    Directory of Open Access Journals (Sweden)

    Jennifer S Lord

    2017-07-01

    Full Text Available Females of all blood-feeding arthropod vectors must find and feed on a host in order to produce offspring. For tsetse-vectors of the trypanosomes that cause human and animal African trypanosomiasis-the problem is more extreme, since both sexes feed solely on blood. Host location is thus essential both for survival and reproduction. Host population density should therefore be an important driver of population dynamics for haematophagous insects, and particularly for tsetse, but the role of host density is poorly understood. We investigate the issue using data on changes in numbers of tsetse (Glossina morsitans morsitans Westwood caught during a host elimination experiment in Zimbabwe in the 1960s. During the experiment, numbers of flies caught declined by 95%. We aimed to assess whether models including starvation-dependent mortality could explain observed changes in tsetse numbers as host density declined. An ordinary differential equation model, including starvation-dependent mortality, captured the initial dynamics of the observed tsetse population. However, whereas small numbers of tsetse were caught throughout the host elimination exercise, the modelled population went extinct. Results of a spatially explicit agent-based model suggest that this discrepancy could be explained by immigration of tsetse into the experimental plot. Variation in host density, as a result of natural and anthropogenic factors, may influence tsetse population dynamics in space and time. This has implications for Trypanosoma brucei rhodesiense transmission. Increased tsetse mortality as a consequence of low host density may decrease trypanosome transmission, but hungrier flies may be more inclined to bite humans, thereby increasing the risk of transmission to humans. Our model provides a way of exploring the role of host density on tsetse population dynamics and could be incorporated into models of trypanosome transmission dynamics to better understand how spatio

  12. A hierarchical model for regional analysis of population change using Christmas Bird Count data, with application to the American Black Duck

    Science.gov (United States)

    Link, W.A.; Sauer, J.R.; Niven, D.K.

    2006-01-01

    Analysis of Christmas Bird Count (CBC) data is complicated by the need to account for variation in effort on counts and to provide summaries over large geographic regions. We describe a hierarchical model for analysis of population change using CBC data that addresses these needs. The effect of effort is modeled parametrically, with parameter values varying among strata as identically distributed random effects. Year and site effects are modeled hierarchically, accommodating large regional variation in number of samples and precision of estimates. The resulting model is complex, but a Bayesian analysis can be conducted using Markov chain Monte Carlo techniques. We analyze CBC data for American Black Ducks (Anas rubripes), a species of considerable management interest that has historically been monitored using winter surveys. Over the interval 1966-2003, Black Duck populations showed distinct regional patterns of population change. The patterns shown by CBC data are similar to those shown by the Midwinter Waterfowl Inventory for the United States.

  13. Bird guard

    Science.gov (United States)

    Fairchild, Dana M [Armour, SD

    2010-03-02

    The bird guard provides a device to protect electrical insulators comprising a central shaft; a clamp attached to an end of the shaft to secure the device to a transmission tower; a top and bottom cover to shield transmission tower insulators; and bearings to allow the guard to rotate in order to frighten birds away from the insulators.

  14. Do bird assemblages predict susceptibility by e-waste pollution? A comparative study based on species- and guild-dependent responses in China agroecosystems.

    Science.gov (United States)

    Zhang, Qiang; Wu, Jiangping; Sun, Yuxin; Zhang, Min; Mai, Bixian; Mo, Ling; Lee, Tien Ming; Zou, Fasheng

    2015-01-01

    Indirect effects of electronic waste (e-waste) have been proposed as a causal factor in the decline of bird populations, but analyses of the severity impacts on community assembly are currently lacking. To explore how population abundance/species diversity are influenced, and which functional traits are important in determining e-waste susceptibility, here we surveyed breeding and overwintering birds with a hierarchically nested sampling design, and used linear mixed models to analyze changes in bird assemblages along an exposure gradient in South China. Total bird abundance and species diversity decreased with e-waste severity (exposed polluted sites. A high pairwise similarity between exposed and surrounding sites indicates a diffuse effect of pollutants on the species assembly at local scale. We show that sensitivity to e-waste severity varies substantially across functional guild, with the prevalence of woodland insectivorous and grassland specialists declining, while some open farmland generalists such as arboreal frugivores, and terrestrial granivores were also rare. By contrast, the response of waterbirds, omnivorous and non-breeding visitors seem to be tolerable to a wide range of pollution so far. These findings underscore that improper e-waste dismantling results in a severe decline of bird diversity, and the different bird assemblages on polluted and natural farmlands imply species- and guild-dependent susceptibility with functional traits. Moreover, a better understanding of the impact of e-waste with different pollution levels, combined multiple pollutants, and in a food-web context on bird is required in future.

  15. The need for future wetland bird studies: scales of habitat use as input for ecological restoration and spatial water management

    NARCIS (Netherlands)

    Platteeuw, M.; Foppen, R.P.B.; Eerden, van M.R.

    2010-01-01

    All over Europe, wetlands have decreased in size, lost their original dynamics and became fragmented as the consequence of an ever increasing human land use. These processes have resulted in losses of nature values, among which declines in marshland bird populations. Ecological restoration of

  16. Browsing patterns of white-tailed deer following increased timber harvest and a decline in population density

    Science.gov (United States)

    Shawn M. Crimmins; John W. Edwards; W. Mark Ford; Patrick D. Keyser; James M. Crum

    2010-01-01

    We examined browsing patterns of white-tailed deer (Odocoileus virginianus) on a site in the central Appalachians that experienced a substantial (>50%) reduction in deer population density and an increase in the amount of timber harvest since 2001. We sampled woody browse in and immediately adjacent to 12 clearcuts ranging in age from 0-5 years...

  17. Improved analysis of long-term monitoring data demonstrates marked regional declines of bat populations in the eastern United States

    Science.gov (United States)

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

    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...

  18. Gender Patterns in Bird-related Recreation in the USA and UK

    Directory of Open Access Journals (Sweden)

    Caren B. Cooper

    2010-12-01

    Full Text Available Recent studies show inter-related trends in both adult and youth populations in developed nations: a shift away from nature-based recreation, an overall decline in physical activity, and increasing obesity. For this study we examined gender patterns in a nature-based activity, observing wild birds, popular in two developed nations, the USA and UK. We collated data from several organizations and categorized data sources as representing activities that involve varying degrees of competitiveness and acting authoritatively. Patterns were consistent with the hypotheses that gender differences in preferred types of bird-related recreation reflected well documented gender-specific differences in preferences for competition and propensity to act authoritatively. Observing birds encompassed both a recreational hobby, "bird watching," that was female biased in the USA, and a competitive sport, "birding," that was heavily male biased among adults, but not youth, in both the USA and UK. Because of differences in gender participation in bird-related activities, fostering both competitive and noncompetitive bird-related activities is necessary to increase the likelihood of bringing larger segments of the population into nature-based recreation.

  19. Long-term decline of the populations of Fucales (Cystoseira spp. and Sargassum spp.) in the Albères coast (France, North-western Mediterranean).

    Science.gov (United States)

    Thibaut, Thierry; Pinedo, Susana; Torras, Xavier; Ballesteros, Enric

    2005-12-01

    Only five of fourteen species of Fucales reported at the end of the XIXth century are currently present in the Albères Coast (France, NW Mediterranean). According to historical data there has been a steady decrease of all the populations since the 1940s. Seven taxa now extinct (Cystoseira crinita, Cystoseira barbata, Cystoseira foeniculacea f. tenuiramosa, Cystoseira spinosa, Cystoseira spinosa var. compressa, Sargassum hornschuchii and Sargassum vulgare) were considered frequent and some of them were the dominant and engineering species in several phytobenthic assemblages. Moreover, only one of the five species left, shows no signs of regression (Cystoseira compressa), two are considered as rare (Cystoseira caespitosa, Cystoseira zosteroides), and one is very rare (Cystoseira elegans). Cystoseira mediterranea, a species that was reported to make a continuous belt along the shores of the Albères coast, has almost disappeared from some areas. Overgrazing by sea urchins, outcompetition by mussels, habitat destruction, scientific research sampling and, probably, human trampling and chemical pollution are to be blamed for the decline of populations thriving in shallow waters. Deep-water species have been affected by an increase in water turbidity and, probably, chemical pollution and direct plant destruction attributed to net fishing. If degradation of the environmental conditions continues, the remaining Cystoseira species will face a most unwelcome prospect. Even after the removal of the causes that led to its die-off, natural restoration of extinct species seems not to be possible because the decline has also affected populations from nearby areas and zygotes are unable to disperse over long distances. Urgent management actions have to be designed in order to improve the current situation of the populations of Fucales in the Albères coast.

  20. Threatened bird valuation in Australia.

    Directory of Open Access Journals (Sweden)

    Kerstin K Zander

    Full Text Available Threatened species programs need a social license to justify public funding. A contingent valuation survey of a broadly representative sample of the Australian public found that almost two thirds (63% supported funding of threatened bird conservation. These included 45% of a sample of 645 respondents willing to pay into a fund for threatened bird conservation, 3% who already supported bird conservation in another form, and 15% who could not afford to pay into a conservation fund but who nevertheless thought that humans have a moral obligation to protect threatened birds. Only 6% explicitly opposed such payments. Respondents were willing to pay about AUD 11 annually into a conservation fund (median value, including those who would pay nothing. Highest values were offered by young or middle aged men, and those with knowledge of birds and those with an emotional response to encountering an endangered bird. However, the prospect of a bird going extinct alarmed almost everybody, even most of those inclined to put the interests of people ahead of birds and those who resent the way threatened species sometimes hold up development. The results suggest that funding for threatened birds has widespread popular support among the Australian population. Conservatively they would be willing to pay about AUD 14 million per year, and realistically about AUD 70 million, which is substantially more than the AUD 10 million currently thought to be required to prevent Australian bird extinctions.

  1. Non-breeding range size predicts the magnitude of population trends in trans-Saharan migratory passerine birds

    Czech Academy of Sciences Publication Activity Database

    Koleček, Jaroslav; Procházka, Petr; Ieronymidou, C.; Burfield, I. J.; Reif, J.

    2018-01-01

    Roč. 127, č. 4 (2018), s. 599-606 ISSN 0030-1299 R&D Projects: GA ČR GA13-06451S Institutional support: RVO:68081766 Keywords : stork Ciconia ciconia * life history * survival rates * connectivity * traits * Europe * diversity * evolution * patterns * declines Subject RIV: EG - Zoology OBOR OECD: Ecology Impact factor: 4.030, year: 2016

  2. Five decades on: Use of historical weaning size data reveals that a decrease in maternal foraging success underpins the long-term decline in population of southern elephant seals (Mirounga leonina).

    Science.gov (United States)

    Clausius, Ella; McMahon, Clive R; Hindell, Mark A

    2017-01-01

    The population of Southern elephant seals (Mirounga leonina) at Macquarie Island has declined since the 1960s, and is thought to be due to changing oceanic conditions leading to reductions in the foraging success of Macquarie Island breeding females. To test this hypothesis, we used a 55-year-old data set on weaning size of southern elephant seals to quantify a decrease in weaning size from a period of population stability in 1950s to its present state of on-going decline. Being capital breeders, the size of elephant seal pups at weaning is a direct consequence of maternal foraging success in the preceding year. During the 1940-1950s, the mean of female pups at weaning was similar between the Heard and Macquarie Island populations, while the snout-tail-length length of male weaners from Heard Island were longer than their conspecifics at Macquarie Island. Additionally, the snout-tail-length of pups at weaning decreased by 3cm between the 1950s and 1990s in the Macquarie Island population, concurrent with the observed population decline. Given the importance of weaning size in determining first-year survival and recruitment rates, the decline in the size at weaning suggests that the decline in the Macquarie Island population has, to some extent, been driven by reduced maternal foraging success, consequent declines in the size of pups at weaning, leading to reduced first-year survival rates and recruitment of breeding females into the population 3 to 4 years later.

  3. Local Recurrence in Women With Stage I Breast Cancer: Declining Rates Over Time in a Large, Population-Based Cohort

    Energy Technology Data Exchange (ETDEWEB)

    Canavan, Joycelin, E-mail: canavanjoycelin@gmail.com [Radiation Therapy Program and Breast Cancer Outcomes Unit, British Columbia Cancer Agency, Vancouver Island Centre, University of British Columbia, Victoria, British Columbia (Canada); Truong, Pauline T.; Smith, Sally L. [Radiation Therapy Program and Breast Cancer Outcomes Unit, British Columbia Cancer Agency, Vancouver Island Centre, University of British Columbia, Victoria, British Columbia (Canada); Lu, Linghong; Lesperance, Mary [Department of Mathematics and Statistics, University of Victoria, British Columbia (Canada); Olivotto, Ivo A. [Department of Radiation Oncology, Tom Baker Cancer Centre, University of Calgary (Canada)

    2014-01-01

    increased. These changes contributed to the observed declining LR rates among patients treated with breast-conserving therapy.

  4. Effects of prairie fragmentation on the nest success of breeding birds in the midcontinental United States

    Science.gov (United States)

    Herkert, J.R.; Reinking, D.L.; Wiedenfeld, D.A.; Winter, M.; Zimmerman, J.L.; Jensen, W.E.; Finck, E.J.; Koford, Rolf R.; Wolfe, D.H.; Sherrod, S.K.; Jenkins, M.A.; Faaborg, John; Robinson, S.K.

    2003-01-01

    Grassland fragmentation and habitat loss are hypothesized to be contributing to widespread grassland bird declines in North America due to the adverse effects of fragmentation on breeding bird abundance and reproductive success. To assess the effects of fragmentation on the reproductive success of grassland birds, we measured rates of nest predation and brood parasitism for four species of birds ( Grasshopper Sparrow [Ammodramus savannaru], Henslow's Sparrow[Ammodramus henslowii], Eastern Meadowlark [ Sturnella magna], and Dickcissel [ Spiza Americana] ) in 39 prairie fragments ranging from 24 to>40,000 ha in size in five states in the mid-continental United States. Throughout the region, nest-predation rates were significantly influenced by habitat fragmentation. Nest predation was highest in small (1000 ha ) prairie fragments. Rates of brood parasitism by Brown-headed Cowbirds (   Molothrus ater ), however, were not consistently related to fragment size and instead were more strongly related to regional cowbird abundance, being significantly higher in regions with high cowbird abundance. Differences in nest-predation rates between large fragments ( 54–68% of all nests lost to predators ) and small fragments ( 78–84% lost to predators ) suggest that fragmentation of prairie habitats may be contributing to regional declines of grassland birds. Maintaining grassland bird populations, therefore, may require protection and restoration of large prairie areas.

  5. 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

    OpenAIRE

    Stapley, J.; Garcia, M.; Andrews, R.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 li...

  6. Climate change impacts: birds

    NARCIS (Netherlands)

    Tomotani, B.M.; Ramakers, J.J.C.; Gienapp, P.

    2016-01-01

    Climate change can affect populations and species in various ways. Rising temperatures can shift geographical distributions and lead to (phenotypic or genetic) changes in traits, mostly phenology, which may affect demography. Most of these effects are well documented in birds. For example, the

  7. Effects of vegetation, corridor width and regional land use on early successional birds on powerline corridors.

    Science.gov (United States)

    Askins, Robert A; Folsom-O'Keefe, Corrine M; Hardy, Margaret C

    2012-01-01

    Powerline rights-of-way (ROWs) often provide habitat for early successional bird species that have suffered long-term population declines in eastern North America. To determine how the abundance of shrubland birds varies with habitat within ROW corridors and with land use patterns surrounding corridors, we ran Poisson regression models on data from 93 plots on ROWs and compared regression coefficients. We also determined nest success rates on a 1-km stretch of ROW. Seven species of shrubland birds were common in powerline corridors. However, the nest success rates for prairie warbler (Dendroica discolor) and field sparrow (Spizella pusilla) were bird species were more abundant on narrower ROWs or at sites with lower vegetation or particular types of vegetation, indicating that vegetation management could be refined to favor species of high conservation priority. Also, several species were more abundant in ROWs traversing unfragmented forest than those near residential areas or farmland, indicating that corridors in heavily forested regions may provide better habitat for these species. In the area where we monitored nests, brood parasitism by brown-headed cowbirds (Molothrus ater) occurred more frequently close to a residential area. Although ROWs support dense populations of shrubland birds, those in more heavily developed landscapes may constitute sink habitat. ROWs in extensive forests may contribute more to sustaining populations of early successional birds, and thus may be the best targets for habitat management.

  8. Effects of vegetation, corridor width and regional land use on early successional birds on powerline corridors.

    Directory of Open Access Journals (Sweden)

    Robert A Askins

    Full Text Available Powerline rights-of-way (ROWs often provide habitat for early successional bird species that have suffered long-term population declines in eastern North America. To determine how the abundance of shrubland birds varies with habitat within ROW corridors and with land use patterns surrounding corridors, we ran Poisson regression models on data from 93 plots on ROWs and compared regression coefficients. We also determined nest success rates on a 1-km stretch of ROW. Seven species of shrubland birds were common in powerline corridors. However, the nest success rates for prairie warbler (Dendroica discolor and field sparrow (Spizella pusilla were <21%, which is too low to compensate for estimated annual mortality. Some shrubland bird species were more abundant on narrower ROWs or at sites with lower vegetation or particular types of vegetation, indicating that vegetation management could be refined to favor species of high conservation priority. Also, several species were more abundant in ROWs traversing unfragmented forest than those near residential areas or farmland, indicating that corridors in heavily forested regions may provide better habitat for these species. In the area where we monitored nests, brood parasitism by brown-headed cowbirds (Molothrus ater occurred more frequently close to a residential area. Although ROWs support dense populations of shrubland birds, those in more heavily developed landscapes may constitute sink habitat. ROWs in extensive forests may contribute more to sustaining populations of early successional birds, and thus may be the best targets for habitat management.

  9. Declining trend in the incidence of biopsy-verified coeliac disease in the adult population of Finland, 2005-2014.

    Science.gov (United States)

    Virta, L J; Saarinen, M M; Kolho, K-L

    2017-12-01

    The frequency of coeliac disease (CD) has been on the rise over the past decades, especially in Western Europe, but current trends are unclear. To research the recent temporal changes in the incidence of adult, biopsy-verified coeliac disease and dermatitis herpetiformis (DH) in Finland, a country with a high frequency of coeliac disease. All coeliac disease and DH cases diagnosed at age 20-79 years during 2005-2014 were retrieved from a nationwide database documenting all applicants for monthly compensation to cover the extra cost of maintaining a gluten-free diet. This benefit is granted on the basis of histology, not socioeconomic status. Temporal trends in the annual incidences were estimated using Poisson regression analyses. The total incidence of coeliac disease decreased from 33/100 000 during the years 2005-2006 to 29/100 000 during 2013-2014. The mean annual incidence of coeliac disease was nearly twice as high among women as among men, 42 vs 22 per 100 000, respectively. For middle- and old-aged women, the average rate of decrease in incidence was 4.8% (95% CI 3.9-5.7) per year and for men 3.0% (1.8-4.1) (P for linear trend coeliac disease has increased during the past decades, the incidence of biopsy-verified diagnoses is not increasing, which suggests that exposure to yet unidentified triggering factors for coeliac disease has plateaued among the Finnish adult population. © 2017 John Wiley & Sons Ltd.

  10. Spatio-temporal variation in age structure and abundance of the endangered snail kite: Pooling across regions masks a declining and aging population

    Science.gov (United States)

    Reichert, Brian E.; 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.

  11. Spatio-Temporal Variation in Age Structure and Abundance of the Endangered Snail Kite: Pooling across Regions Masks a Declining and Aging Population.

    Science.gov (United States)

    Reichert, Brian E; Kendall, William L; Fletcher, Robert J; Kitchens, Wiley M

    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.

  12. Hawaii ESI: BIRDS (Bird Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for endangered waterbirds and passerine birds, migratory shorebirds and waterfowl, gulls and terns,...

  13. SUHARTO’S POPULATION POLICY IN CONTEMPORARY INDONESIA : FAMILY PLANNING PROGRAM, MARRIAGE ACT OR COMPULSORY EDUCATION HAS THE GREATEST IMPACT TO FERTILITY DECLINE?

    Directory of Open Access Journals (Sweden)

    Dyah Anantalia Widyastari

    2016-05-01

    Full Text Available Fertility in Indonesia has been falling significantly, from an average total fertility rate of 5.6 children per women in 1970s to 4.1 in 1980, and 2.6 in 2010. This paper attempts to explore which and how Suharto’s population policies have played role in Indonesia’s fertility decline. Whilst the adoption of modern contraceptive was perceived as the major determinant of fertility decline in Indonesia, changes in Indonesia’s political order and socio-economic development also contribute a considerable effect to Indonesians’ familial norms. The implementation of 9-year compulsory education had placed a strong foundation for the future Indonesian human capital and enabled women to obtain higher opportunities for schooling. Beside facilitates the diffusion of ideas among young people and opened up their perspective toward reproductive rights and self actualization, education also increases women’s opportunities to participate in laborforce. With the increasing roles outside the domestic sector, delaying age of marriage and limiting family size becomes a choice for women in contemporary Indonesia. The marriage act, however, was perceived as an accelerator rather than a predictor in increasing age of first marriage. Regardless the existence of the Marriage Law 1974, age of first marriage is likely to increase with increasing of education, although maybe in a slower rate.

  14. Blood mercury concentrations are associated with decline in liver function in an elderly population: a panel study.

    Science.gov (United States)

    Lee, Mee-Ri; Lim, Youn-Hee; Lee, Bo-Eun; Hong, Yun-Chul

    2017-03-04

    Mercury is a toxic heavy metal and is known to affect many diseases. However, few studies have examined the effects of mercury exposure on liver function in the general population. We examined the association between blood mercury concentrations and liver enzyme levels in the elderly. We included 560 elderly participants (60 years or older) who were recruited from 2008 to 2010 and followed up to 2014. Subjects visited a community welfare center and underwent a medical examination and measurement of mercury levels up to five times. Analyses using generalized estimating equations model were performed after adjusting for age, sex, education, overweight, alcohol consumption, smoking, regular exercise, high-density lipoproteins cholesterol, and total calorie intake. Additionally, we estimated interaction effects of alcohol consumption with mercury and mediation effect of oxidative stress in the relationship between mercury levels and liver function. The geometric mean (95% confidence interval (CI)) of blood mercury concentrations was 2.81 μg/L (2.73, 2.89). Significant relationships were observed between blood mercury concentrations and the level of liver enzymes, including aspartate aminotransferase (AST), alanine aminotransferase (ALT), and gamma glutamyl transferase (GGT), after adjusting for potential confounders (P mercury quartile compared to those with the lowest quartile. Particularly, regular alcohol drinkers showed greater effect estimates of mercury on the liver function than non-drinkers groups. There was no mediation effect of oxidative stress in the relationship between blood mercury concentrations and liver function. Our results suggest that blood mercury levels are associated with elevated liver enzymes and interact with alcohol consumption for the association in the elderly.

  15. Quantifying the contribution of statins to the decline in population mean cholesterol by socioeconomic group in England 1991 - 2012: a modelling study.

    Directory of Open Access Journals (Sweden)

    Chris Kypridemos

    Full Text Available Serum total cholesterol is one of the major targets for cardiovascular disease prevention. Statins are effective for cholesterol control in individual patients. At the population level, however, their contribution to total cholesterol decline remains unclear. The aim of this study was to quantify the contribution of statins to the observed fall in population mean cholesterol levels in England over the past two decades, and explore any differences between socioeconomic groups.This is a modelling study based on data from the Health Survey for England. We analysed changes in observed mean total cholesterol levels in the adult England population between 1991-92 (baseline and 2011-12. We then compared the observed changes with a counterfactual 'no statins' scenario, where the impact of statins on population total cholesterol was estimated and removed. We estimated uncertainty intervals (UI using Monte Carlo simulation, where confidence intervals (CI were impractical. In 2011-12, 13.2% (95% CI: 12.5-14.0% of the English adult population used statins at least once per week, compared with 1991-92 when the proportion was just 0.5% (95% CI: 0.3-1.0%. Between 1991-92 and 2011-12, mean total cholesterol declined from 5.86 mmol/L (95% CI: 5.82-5.90 to 5.17 mmol/L (95% CI: 5.14-5.20. For 2011-12, mean total cholesterol was lower in more deprived groups. In our 'no statins' scenario we predicted a mean total cholesterol of 5.36 mmol/L (95% CI: 5.33-5.40 for 2011-12. Statins were responsible for approximately 33.7% (95% UI: 28.9-38.8% of the total cholesterol reduction since 1991-92. The statin contribution to cholesterol reduction was greater among the more deprived groups of women, while showing little socio-economic gradient among men.Our model suggests that statins explained around a third of the substantial falls in total cholesterol observed in England since 1991. Approximately two thirds of the cholesterol decrease can reasonably be attributed non

  16. Conservation status and recovery strategies for endemic Hawaiian birds

    Science.gov (United States)

    Banko, Paul C.; David, Reginald E.; Jacobi, James D.; Banko, Winston E.

    2001-01-01

    Populations of endemic Hawaiian birds declined catastrophically following the colonization of the islands by Polynesians and later cultures. Extinction is still occurring, and recovery programs are urgently needed to prevent the disappearance of many other species. Programs to recover the endemic avifauna incorporate a variety of conceptual and practical approaches that are constrained by biological, financial, social, and legal factors. Avian recovery is difficult to implement in Hawai‘i because a variety of challenging biological factors limit bird populations. Hawaiian birds are threatened by alien predatory mammals, introduced mosquitoes that transmit diseases, alien invertebrate parasites and predators that reduce invertebrate food resources, and alien animals and plants that destroy and alter habitats. Life in the remote Hawaiian Archipelago has imposed other biological constraints to avian recovery, including limited geographical distributions and small population sizes. Recovery of the endemic avifauna is also challenging because resources are insufficient to mitigate the many complex, interacting factors that limit populations. Decisions must be made for allocating limited resources to species teetering on the brink of extinction and those in decline. If funds are spent primarily on saving the rarest species, more abundant species will decline and become more difficult to recover. However, critically rare species will disappear if efforts are directed mainly towards restoring species that are declining but not in immediate danger of becoming extinct. Determining priorities is difficult also because management is needed both to supplement bird populations and to restore habitats of many species. Rare species cannot respond quickly to management efforts intended only to improve habitat and reduce limiting factors. Recovery is slow, if it occurs at all, because years or decades are generally required for habitat rehabilitation and because small populations

  17. Managing mainland salt marshes for breeding birds

    OpenAIRE

    Maier, Martin

    2014-01-01

    The Wadden Sea region is one of the most important breeding areas in Western Europe for coastal breeding bird species. It is expected that management of salt marshes is important for successful conservation of breeding bird populations but the impact of management on the habitat quality for breeding birds is still not fully understood. In this study the effects of management on the three crucial habitat characteristics for breeding birds were studied on mainland salt marshes: effects of manag...

  18. Predisposition to bark beetle attack by root herbivores and associated pathogens: Roles in forest decline, gap formation, and persistence of endemic bark beetle populations

    DEFF Research Database (Denmark)

    Aukema, Brian H.; Zhu, Jun; Møller, Jesper

    2010-01-01

    . This interaction results in an expanding forest gap, with subsequent colonization by early-successional vegetation. Spatial position strongly affects the likelihood of tree mortality. A red pine is initially very likely to avoid attack by tree-killing Ips beetles, but attack becomes increasingly likely......, in that the proportion of killed trees that were not first colonized by root organisms increases. This positive feedback is very weak, however, and we propose the slope between beetle population density and reliance on host stress as a quantitative distinction along a gradient from noneruptive through eruptive species....... Almost all trees colonized by Ips were subsequently colonized by wood borers, likely a source of negative feedback. We discuss implications to our overall understanding of cross-scale interactions, between-guild interactions, forest declines, and eruptive thresholds....

  19. Can Ingestion of Lead Shot and Poisons Change Population Trends of Three European Birds: Grey Partridge, Common Buzzard, and Red Kite?

    Directory of Open Access Journals (Sweden)

    Carolyn B Meyer

    Full Text Available Little is known about the magnitude of the effects of lead shot ingestion alone or combined with poisons (e.g., in bait or seeds/granules containing pesticides on population size, growth, and extinction of non-waterbird avian species that ingest these substances. We used population models to create example scenarios demonstrating how changes in these parameters might affect three susceptible species: grey partridge (Perdix perdix, common buzzard (Buteo buteo, and red kite (Milvus milvus. We added or subtracted estimates of mortality due to lead shot ingestion (4-16% of mortality, depending on species and poisons (4-46% of mortality reported in the UK or France to observed mortality of studied populations after models were calibrated to observed population trends. Observed trends were decreasing for partridge (in continental Europe, stable for buzzard (in Germany, and increasing for red kite (in Wales. Although lead shot ingestion and poison at modeled levels did not change the trend direction for the three species, they reduced population size and slowed population growth. Lead shot ingestion at modeled rates reduced population size of partridges by 10%, and when combined with bait and pesticide poisons, by 18%. For buzzards, decrease in mean population size by lead shot and poisons combined was much smaller (≤ 1%. The red kite population has been recovering; however, modeled lead shot ingestion reduced its annual growth rate from 6.5% to 4%, slowing recovery. If mortality from poisoned baits could be removed, the kite population could potentially increase at a rapid annual rate of 12%. The effects are somewhat higher if ingestion of these substances additionally causes sublethal reproductive impairment. These results have uncertainty but suggest that declining or recovering populations are most sensitive to lead shot or poison ingestion, and removal of poisoned baits can have a positive impact on recovering raptor populations that frequently

  20. Can Ingestion of Lead Shot and Poisons Change Population Trends of Three European Birds: Grey Partridge, Common Buzzard, and Red Kite?

    Science.gov (United States)

    Meyer, Carolyn B; Meyer, Joseph S; Francisco, Alex B; Holder, Jennifer; Verdonck, Frederik

    2016-01-01

    Little is known about the magnitude of the effects of lead shot ingestion alone or combined with poisons (e.g., in bait or seeds/granules containing pesticides) on population size, growth, and extinction of non-waterbird avian species that ingest these substances. We used population models to create example scenarios demonstrating how changes in these parameters might affect three susceptible species: grey partridge (Perdix perdix), common buzzard (Buteo buteo), and red kite (Milvus milvus). We added or subtracted estimates of mortality due to lead shot ingestion (4-16% of mortality, depending on species) and poisons (4-46% of mortality) reported in the UK or France to observed mortality of studied populations after models were calibrated to observed population trends. Observed trends were decreasing for partridge (in continental Europe), stable for buzzard (in Germany), and increasing for red kite (in Wales). Although lead shot ingestion and poison at modeled levels did not change the trend direction for the three species, they reduced population size and slowed population growth. Lead shot ingestion at modeled rates reduced population size of partridges by 10%, and when combined with bait and pesticide poisons, by 18%. For buzzards, decrease in mean population size by lead shot and poisons combined was much smaller (≤ 1%). The red kite population has been recovering; however, modeled lead shot ingestion reduced its annual growth rate from 6.5% to 4%, slowing recovery. If mortality from poisoned baits could be removed, the kite population could potentially increase at a rapid annual rate of 12%. The effects are somewhat higher if ingestion of these substances additionally causes sublethal reproductive impairment. These results have uncertainty but suggest that declining or recovering populations are most sensitive to lead shot or poison ingestion, and removal of poisoned baits can have a positive impact on recovering raptor populations that frequently feed on

  1. Massive nest-box supplementation boosts fecundity, survival and even immigration without altering mating and reproductive behaviour in a rapidly recovered bird population.

    Directory of Open Access Journals (Sweden)

    Karine Berthier

    Full Text Available Habitat restoration measures may result in artificially high breeding density, for instance when nest-boxes saturate the environment, which can negatively impact species' demography. Potential risks include changes in mating and reproductive behaviour such as increased extra-pair paternity, conspecific brood parasitism, and polygyny. Under particular cicumstances, these mechanisms may disrupt reproduction, with populations dragged into an extinction vortex. With the use of nuclear microsatellite markers, we investigated the occurrence of these potentially negative effects in a recovered population of a rare secondary cavity-nesting farmland bird of Central Europe, the hoopoe (Upupa epops. High intensity farming in the study area has resulted in a total eradication of cavity trees, depriving hoopoes from breeding sites. An intensive nest-box campaign rectified this problem, resulting in a spectacular population recovery within a few years only. There was some concern, however, that the new, high artificially-induced breeding density might alter hoopoe mating and reproductive behaviour. As the species underwent a serious demographic bottleneck in the 1970-1990s, we also used the microsatellite markers to reconstitute the demo-genetic history of the population, looking in particular for signs of genetic erosion. We found i a low occurrence of extra-pair paternity, polygyny and conspecific brood parasitism, ii a high level of neutral genetic diversity (mean number of alleles and expected heterozygosity per locus: 13.8 and 83%, respectively and, iii evidence for genetic connectivity through recent immigration of individuals from well differentiated populations. The recent increase in breeding density did thus not induce so far any noticeable detrimental changes in mating and reproductive behaviour. The demographic bottleneck undergone by the population in the 1970s-1990s was furthermore not accompanied by any significant drop in neutral genetic

  2. Using Autumn Hawk Watch to track raptor migration and to monitor populations of North American birds of prey

    Science.gov (United States)

    Kyle McCarty; Keith L. Bildstein

    2005-01-01

    Raptors are secretive, area-sensitive predators whose populations can be logistically difficult and financially prohibitive to monitor. Many North American populations of raptors are migratory however, and on migration raptors are frequently counted at traditional migration watchsites. Experiences at Hawk Mountain Sanctuary (HMS) and elsewhere suggest that long-term...

  3. Artificial light at night confounds broad-scale habitat use by migrating birds

    Science.gov (United States)

    McLaren, James D.; Buler, Jeffrey J.; Schreckengost, Tim; Smolinsky, Jaclyn A.; Boone, Matthew; van Loon, E. Emiel; Dawson, Deanna K.; Walters, Eric L.

    2018-01-01

    With many of the world's migratory bird populations in alarming decline, broad-scale assessments of responses to migratory hazards may prove crucial to successful conservation efforts. Most birds migrate at night through increasingly light-polluted skies. Bright light sources can attract airborne migrants and lead to collisions with structures, but might also influence selection of migratory stopover habitat and thereby acquisition of food resources. We demonstrate, using multi-year weather radar measurements of nocturnal migrants across the northeastern U.S., that autumnal migrant stopover density increased at regional scales with proximity to the brightest areas, but decreased within a few kilometers of brightly-lit sources. This finding implies broad-scale attraction to artificial light while airborne, impeding selection for extensive forest habitat. Given that high-quality stopover habitat is critical to successful migration, and hindrances during migration can decrease fitness, artificial lights present a potentially heightened conservation concern for migratory bird populations.

  4. Columbia River ESI: BIRDS (Bird Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for wading birds, shorebirds, waterfowl, diving birds, seabirds, passerine birds, gulls, and terns in...

  5. Birds Kept as Pets

    Science.gov (United States)

    ... of pet birds. Because of the risk of avian influenza (bird flu), USDA restricts the importation of pet birds from ... or look dirty may be ill. Learn the signs of illness in a bird, which include appearing ...

  6. Effects of wildlife forestry on abundance of breeding birds in bottomland hardwood forests of Louisiana

    Science.gov (United States)

    Norris, Jennifer L.; Chamberlain, Michael J.; Twedt, Daniel J.

    2009-01-01

    Effects of silvicultural activities on birds are of increasing interest because of documented national declines in breeding bird populations for some species and the potential that these declines are in part due to changes in forest habitat. Silviculturally induced disturbances have been advocated as a means to achieve suitable forest conditions for priority wildlife species in bottomland hardwood forests. We evaluated how silvicultural activities on conservation lands in bottomland hardwood forests of Louisiana, USA, influenced species-specific densities of breeding birds. Our data were from independent studies, which used standardized point-count surveys for breeding birds in 124 bottomland hardwood forest stands on 12 management areas. We used Program DISTANCE 5.0, Release 2.0 (Thomas et al. 2006) to estimate density for 43 species with > 50 detections. For 36 of those species we compared density estimates among harvest regimes (individual selection, group selection, extensive harvest, and no harvest). We observed 10 species with similar densities in those harvest regimes compared with densities in stands not harvested. However, we observed 10 species that were negatively impacted by harvest with greater densities in stands not harvested, 9 species with greater densities in individual selection stands, 4 species with greater densities in group selection stands, and 4 species with greater densities in stands receiving an extensive harvest (e.g., > 40% canopy removal). Differences in intensity of harvest influenced densities of breeding birds. Moreover, community-wide avian conservation values of stands subjected to individual and group selection, and stands not harvested, were similar to each other and greater than that of stands subjected to extensive harvest that removed > 40% canopy cover. These results have implications for managers estimating breeding bird populations, in addition to predicting changes in bird communities as a result of prescribed and future

  7. Are neonicotinoid insecticides driving declines of widespread butterflies?

    Directory of Open Access Journals (Sweden)

    Andre S. Gilburn

    2015-11-01

    Full Text Available There has been widespread concern that neonicotinoid pesticides may be adversely impacting wild and managed bees for some years, but recently attention has shifted to examining broader effects they may be having on biodiversity. For example in the Netherlands, declines in insectivorous birds are positively associated with levels of neonicotinoid pollution in surface water. In England, the total abundance of widespread butterfly species declined by 58% on farmed land between 2000 and 2009 despite both a doubling in conservation spending in the UK, and predictions that climate change should benefit most species. Here we build models of the UK population indices from 1985 to 2012 for 17 widespread butterfly species that commonly occur at farmland sites. Of the factors we tested, three correlated significantly with butterfly populations. Summer temperature and the index for a species the previous year are both positively associated with butterfly indices. By contrast, the number of hectares of farmland where neonicotinoid pesticides are used is negatively associated with butterfly indices. Indices for 15 of the 17 species show negative associations with neonicotinoid usage. The declines in butterflies have largely occurred in England, where neonicotinoid usage is at its highest. In Scotland, where neonicotinoid usage is comparatively low, butterfly numbers are stable. Further research is needed urgently to show whether there is a causal link between neonicotinoid usage and the decline of widespread butterflies or whether it simply represents a proxy for other environmental factors associated with intensive agriculture.

  8. Ecological Sustainability of Birds in Boreal Forests

    Directory of Open Access Journals (Sweden)

    Gerald Niemi

    1998-12-01

    Full Text Available We review characteristics of birds in boreal forests in the context of their ecological sustainability under both natural and anthropogenic disturbances. We identify the underlying ecological factors associated with boreal bird populations and their variability, review the interactions between boreal bird populations and disturbance, and describe some tools on how boreal bird populations may be conserved in the future. The boreal system has historically been an area with extensive disturbance such as fire, insect outbreaks, and wind. In addition, the boreal system is vulnerable to global climate change as well as increasing pressure on forest and water resources. Current knowledge indicates that birds play an important role in boreal forests, and sustaining these populations affords many benefits to the health of boreal forests. Many issues must be approached with caution, including the lack of knowledge on our ability to mimic natural disturbance regimes with management, our lack of understanding on fragmentation due to logging activity, which is different from permanent conversion to other land uses such as agriculture or residential area, and our lack of knowledge on what controls variability in boreal bird populations or the linkage between bird population fluctuations and productivity. The essential role that birds can provide is to clarify important ecological concerns and variables that not only will help to sustain bird populations, but also will contribute to the long-term health of the boreal forest for all species, including humans.

  9. Predictors of short-term mortality, cognitive and physical decline in older adults in northwest Russia: a population-based prospective cohort study.

    Science.gov (United States)

    Turusheva, Anna; Frolova, Elena; Hegendoerfer, Eralda; Degryse, Jean-Marie

    2017-08-01

    The classical phenotype, accumulated deficit model and self-report approach of frailty were found not useful in older adults in northwest Russia. More research is needed to identify predictors of adverse outcomes in this population. The aim of this study is to identify predictors of mortality, autonomy and cognitive decline in a population that is characterized by a high cardiovascular morbidity and mortality rate. A population-based prospective cohort study of 611 community-dwelling individuals 65+. Anthropometry, medical history nutritional status were recorded. An evaluation of cognitive, physical and autonomy function, spirometry, and laboratory tests were performed. The total follow-up was 5 years. Multiple imputation, backward stepwise Cox regression analysis, C-statistic, risk reclassification analysis and the bootstrapping techniques were used to analyze the data. We found that the combination of increasing age, male sex, low physical function, low mid-arm muscle area, low forced expiratory volume in 1 s and anemia was associated with mortality for people 65+. The substitution of anemia with anemia + high level of C-reactive protein (hCRP) and the addition of high brain natriuretic peptide (hBNP) levels improved the classification of older persons at risk for mortality. The combination of low physical function, low mid-arm muscle area, low forced expiratory volume in 1 s, anemia with hCRP levels and hBNP identified older persons at a higher risk for mortality. These predictors may be used for the development of a prediction model to detect older people who are at risk for adverse health outcomes in northwest Russia.

  10. Impacts of the Brown Tree Snake: Patterns of Decline and Species Persistence in Guam's Avifauna

    Science.gov (United States)

    Wiles, G.J.; Bart, J.; Beck, R.E.; Aguon, C.F.

    2003-01-01

    Predation by brown tree snakes (Boiga irregularis ) devastated the avifauna of Guam in the Mariana Islands during the last half of the twentieth century, causing the extirpation or serious reduction of most of the island's 25 resident bird species. Past studies have provided qualitative descriptions of the decline of native forest birds but have not considered all species or presented quantitative analyses. We analyzed two sets of survey data gathered in northern Guam between 1976 and 1998 and reviewed unpublished sources to provide a comprehensive account of the impact of brown tree snakes on the island's birds. Our results indicate that 22 species, including 17 of 18 native species, were severely affected by snakes. Twelve species were likely extirpated as breeding residents on the main island, 8 others experienced declines of ≥90% throughout the island or at least in the north, and 2 were kept at reduced population levels during all or much of the study. Declines of ≥90% occurred rapidly, averaging just 8.9 years along three roadside survey routes combined and 1.6 years at a 100-ha forested study site. Declines in northern Guam were also relatively synchronous and occurred from about 1976 to 1986 for most species. The most important factor predisposing a species to coexistence with brown tree snakes was its ability to nest and roost at locations where snakes were uncommon. Large clutch size and large body size were also related to longer persistence times, although large body size appeared to delay, but not prevent, extirpation. Our results draw attention to the enormous detrimental impact that brown tree snakes are likely to have upon invading new areas. Increased containment efforts on Guam are needed to prevent further colonizations, but a variety of additional management efforts would also benefit the island's remaining bird populations.

  11. Five decades on: Use of historical weaning size data reveals that a decrease in maternal foraging success underpins the long-term decline in population of southern elephant seals (Mirounga leonina.

    Directory of Open Access Journals (Sweden)

    Ella Clausius

    Full Text Available The population of Southern elephant seals (Mirounga leonina at Macquarie Island has declined since the 1960s, and is thought to be due to changing oceanic conditions leading to reductions in the foraging success of Macquarie Island breeding females. To test this hypothesis, we used a 55-year-old data set on weaning size of southern elephant seals to quantify a decrease in weaning size from a period of population stability in 1950s to its present state of on-going decline. Being capital breeders, the size of elephant seal pups at weaning is a direct consequence of maternal foraging success in the preceding year. During the 1940-1950s, the mean of female pups at weaning was similar between the Heard and Macquarie Island populations, while the snout-tail-length length of male weaners from Heard Island were longer than their conspecifics at Macquarie Island. Additionally, the snout-tail-length of pups at weaning decreased by 3cm between the 1950s and 1990s in the Macquarie Island population, concurrent with the observed population decline. Given the importance of weaning size in determining first-year survival and recruitment rates, the decline in the size at weaning suggests that the decline in the Macquarie Island population has, to some extent, been driven by reduced maternal foraging success, consequent declines in the size of pups at weaning, leading to reduced first-year survival rates and recruitment of breeding females into the population 3 to 4 years later.

  12. Will a warmer and wetter future cause extinction of native Hawaiian forest birds?

    Science.gov (United States)

    Liao, Wei; Elison Timm, Oliver; Zhang, Chunxi; Atkinson, Carter T; LaPointe, Dennis A; Samuel, Michael D

    2015-12-01

    Isolation of the Hawaiian archipelago produced a highly endemic and unique avifauna. Avian malaria (Plasmodium relictum), an introduced mosquito-borne pathogen, is a primary cause of extinctions and declines of these endemic honeycreepers. Our research assesses how global climate change will affect future malaria risk and native bird populations. We used an epidemiological model to evaluate future bird-mosquito-malaria dynamics in response to alternative climate projections from the Coupled Model Intercomparison Project. Climate changes during the second half of the century accelerate malaria transmission and cause a dramatic decline in bird abundance. Different temperature and precipitation patterns produce divergent trajectories where native birds persist with low malaria infection under a warmer and dryer projection (RCP4.5), but suffer high malaria infection and severe reductions under hot and dry (RCP8.5) or warm and wet (A1B) futures. We conclude that future global climate change will cause significant decreases in the abundance and diversity of remaining Hawaiian bird communities. Because these effects appear unlikely before mid-century, natural resource managers have time to implement conservation strategies to protect this unique avifauna from further decimation. Similar climatic drivers for avian and human malaria suggest that mitigation strategies for Hawai'i have broad application to human health. © 2015 John Wiley & Sons Ltd.

  13. Will a warmer and wetter future cause extinction of native Hawaiian forest birds?

    Science.gov (United States)

    Liao, Wei; Timm, Oliver Elison; Zhang, Chunxi; Atkinson, Carter T.; LaPointe, Dennis; Samuel, Michael D.

    2015-01-01

    Isolation of the Hawaiian archipelago produced a highly endemic and unique avifauna. Avian malaria (Plasmodium relictum), an introduced mosquito-borne pathogen, is a primary cause of extinctions and declines of these endemic honeycreepers. Our research assesses how global climate change will affect future malaria risk and native bird populations. We used an epidemiological model to evaluate future bird-mosquito-malaria dynamics in response to alternative climate projections from the Coupled Model Intercomparison Project (CMIP). Climate changes during the second half of the century accelerate malaria transmission and cause a dramatic decline in bird abundance. Different temperature and precipitation patterns produce divergent trajectories where native birds persist with low malaria infection under a warmer and dryer projection (RCP4.5), but suffer high malaria infection and severe reductions under hot and dry (RCP8.5) or warm and wet (A1B) futures. We conclude that future global climate change will cause significant decreases in the abundance and diversity of remaining Hawaiian bird communities. Because these effects appear unlikely before mid-century, natural resource managers have time to implement conservation strategies to protect this unique avifauna from further decimation. Similar climatic drivers for avian and human malaria suggest that mitigation strategies for Hawai'i have broad application to human health.

  14. Do changes in the frequency, magnitude and timing of extreme climatic events threaten the population viability of coastal birds?

    NARCIS (Netherlands)

    van de Pol, Martijn; Ens, Bruno J.; Heg, Dik; Brouwer, Lyanne; Krol, Johan; Maier, Martin; Exo, Klaus-Michael; Oosterbeek, Kees; Lok, Tamar; Eising, Corine M.; Koffijberg, Kees

    P>1. Climate change encompasses changes in both the means and the extremes of climatic variables, but the population consequences of the latter are intrinsically difficult to study. 2. We investigated whether the frequency, magnitude and timing of rare but catastrophic flooding events have changed

  15. Viability of meta-populations of wetland birds in a fragmented landscape: Testing the key-patch approach

    NARCIS (Netherlands)

    Vermaat, J.E.; Vigneau, N.; Omtzigt, N.

    2008-01-01

    The key patch approach assumes that metapopulations in fragmented landscapes are likely to be viable with at least one "key" sub-population that is sufficiently large to ensure re-colonization of surrounding minor habitat patches. It is based on a minimum viable number of breeding pairs and

  16. Ecological causes of multilevel covariance between size and first-year survival in a wild bird population

    NARCIS (Netherlands)

    Bouwhuis, Sandra; Vedder, Oscar; Garroway, Colin J.; Sheldon, Ben C.

    Estimates of selection in natural populations are frequent but our understanding of ecological causes of selection, and causes of variation in the direction, strength and form of selection is limited. Here, we apply a multilevel framework to partition effects of great tit fledging mass on first-year

  17. Evidence for r- and K-selection in a wild bird population: a reciprocal link between ecology and evolution.

    NARCIS (Netherlands)

    Sæther, S.A.; Visser, M.E.; Grotan, V.; Engen, S.

    2016-01-01

    Understanding the variation in selection pressure on key life-history traits is crucial in our rapidly changing world. Density is rarely considered as a selective agent. To study its importance, we partition phenotypic selection in fluctuating environments into components representing the population

  18. Absolute consistency: individual versus population variation in annual-cycle schedules of a long-distance migrant bird.

    Directory of Open Access Journals (Sweden)

    Jesse R Conklin

    Full Text Available Flexibility in scheduling varies throughout an organism's annual cycle, reflecting relative temporal constraints and fitness consequences among life-history stages. Time-selection can act at different scales, either by limiting the range of alternative strategies in the population, or by increasing the precision of individual performance. We tracked individual bar-tailed godwits Limosa lapponica baueri for two full years (including direct observation during non-breeding seasons in New Zealand and geolocator tracking of round-trip mi