Potential population-level effects of land-use change and climate change

EPA Science Inventory

Climate change and land-use change are poised to be two fo the largest drivers of biological changeover the next century. We explored the potential effects of these two forces on a population of Red-cockaded Woodpeckers (Picoides borealis) at Fort Benning in Georgia, USA. We us...

Newly rare or newly common: evolutionary feedbacks through changes in population density and relative species abundance, and their management implications

PubMed Central

Lankau, Richard A; Strauss, Sharon Y

2011-01-01

Environmental management typically seeks to increase or maintain the population sizes of desirable species and to decrease population sizes of undesirable pests, pathogens, or invaders. With changes in population size come long-recognized changes in ecological processes that act in a density-dependent fashion. While the ecological effects of density dependence have been well studied, the evolutionary effects of changes in population size, via changes in ecological interactions with community members, are underappreciated. Here, we provide examples of changing selective pressures on, or evolution in, species as a result of changes in either density of conspecifics or changes in the frequency of heterospecific versus conspecific interactions. We also discuss the management implications of such evolutionary responses in species that have experienced rapid increases or decreases in density caused by human actions. PMID:25567977

Climate Justice in Rural Southeastern United States: A Review of Climate Change Impacts and Effects on Human Health.

PubMed

Gutierrez, Kristie S; LePrevost, Catherine E

2016-02-03

Climate justice is a local, national, and global movement to protect at-risk populations who are disproportionately affected by climate change. The social context for this review is the Southeastern region of the United States, which is particularly susceptible to climate change because of the geography of the area and the vulnerabilities of the inhabiting populations. Negative human health effects on variable and vulnerable populations within the Southeast region due to changing climate are concerning, as health threats are not expected to produce parallel effects among all individuals. Vulnerable communities, such as communities of color, indigenous people, the geographically isolated, and those who are socioeconomically disadvantaged and already experiencing poor environmental quality, are least able to respond and adapt to climate change. Focusing on vulnerable populations in the Southeastern United States, this review is a synthesis of the recent (2010 to 2015) literature-base on the health effects connected to climate change. This review also addresses local and regional mitigation and adaptation strategies for citizens and leaders to combat direct and indirect human health effects related to a changing climate.

Climate Justice in Rural Southeastern United States: A Review of Climate Change Impacts and Effects on Human Health

PubMed Central

Gutierrez, Kristie S.; LePrevost, Catherine E.

2016-01-01

Climate justice is a local, national, and global movement to protect at-risk populations who are disproportionately affected by climate change. The social context for this review is the Southeastern region of the United States, which is particularly susceptible to climate change because of the geography of the area and the vulnerabilities of the inhabiting populations. Negative human health effects on variable and vulnerable populations within the Southeast region due to changing climate are concerning, as health threats are not expected to produce parallel effects among all individuals. Vulnerable communities, such as communities of color, indigenous people, the geographically isolated, and those who are socioeconomically disadvantaged and already experiencing poor environmental quality, are least able to respond and adapt to climate change. Focusing on vulnerable populations in the Southeastern United States, this review is a synthesis of the recent (2010 to 2015) literature-base on the health effects connected to climate change. This review also addresses local and regional mitigation and adaptation strategies for citizens and leaders to combat direct and indirect human health effects related to a changing climate. PMID:26848673

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

USGS Publications Warehouse

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.

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

PubMed Central

Nolet, Bart A; Bauer, Silke; Feige, Nicole; Kokorev, Yakov I; Popov, Igor Yu; Ebbinge, Barwolt S

2013-01-01

1. The huge changes in population sizes of Arctic-nesting geese offer a great opportunity to study population limitation in migratory animals. In geese, population limitation seems to have shifted from wintering to summering grounds. There, in the Arctic, climate is rapidly changing, and this may impact reproductive performance, and perhaps population size of geese, both directly (e.g. by changes in snow melt) or indirectly (e.g. by changes in trophic interactions). 2. Dark-bellied brent geese (Branta bernicla bernicla L.) increased 20-fold since the 1950s. Its reproduction fluctuates strongly in concert with the 3-year lemming cycle. An earlier analysis, covering the growth period until 1988, did not find evidence for density dependence, but thereafter the population levelled off and even decreased. The question is whether this is caused by changes in lemming cycles, population density or other factors like carry-over effects. 3. Breeding success was derived from proportions of juveniles. We used an information-theoretical approach to investigate which environmental factors best explained the variation in breeding success over nearly 50 years (1960–2008). We subsequently combined GLM predictions of breeding success with published survival estimates to project the population trajectory since 1991 (year of maximum population size). In this way, we separated the effects of lemming abundance and population density on population development. 4. Breeding success was mainly dependent on lemming abundance, the onset of spring at the breeding grounds, and the population size of brent goose. No evidence was found for carry-over effects (i.e. effects of conditions at main spring staging site). Negative density dependence was operating at a population size above c. 200 000 individuals, but the levelling off of the population could be explained by faltering lemming cycles alone. 5. Lemmings have long been known to affect population productivity of Arctic-nesting migratory birds and, more recently, possibly population dynamics of resident bird species, but this is the first evidence for effects of lemming abundance on population size of a migratory bird species. Why lemming cycles are faltering in the last two decades is unclear, but this may be associated with changes in winter climate at Taimyr Peninsula (Siberia). PMID:23419215

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

PubMed

Nolet, Bart A; Bauer, Silke; Feige, Nicole; Kokorev, Yakov I; Popov, Igor Yu; Ebbinge, Barwolt S

2013-07-01

The huge changes in population sizes of Arctic-nesting geese offer a great opportunity to study population limitation in migratory animals. In geese, population limitation seems to have shifted from wintering to summering grounds. There, in the Arctic, climate is rapidly changing, and this may impact reproductive performance, and perhaps population size of geese, both directly (e.g. by changes in snow melt) or indirectly (e.g. by changes in trophic interactions). Dark-bellied brent geese (Branta bernicla bernicla L.) increased 20-fold since the 1950s. Its reproduction fluctuates strongly in concert with the 3-year lemming cycle. An earlier analysis, covering the growth period until 1988, did not find evidence for density dependence, but thereafter the population levelled off and even decreased. The question is whether this is caused by changes in lemming cycles, population density or other factors like carry-over effects. Breeding success was derived from proportions of juveniles. We used an information-theoretical approach to investigate which environmental factors best explained the variation in breeding success over nearly 50 years (1960-2008). We subsequently combined GLM predictions of breeding success with published survival estimates to project the population trajectory since 1991 (year of maximum population size). In this way, we separated the effects of lemming abundance and population density on population development. Breeding success was mainly dependent on lemming abundance, the onset of spring at the breeding grounds, and the population size of brent goose. No evidence was found for carry-over effects (i.e. effects of conditions at main spring staging site). Negative density dependence was operating at a population size above c. 200 000 individuals, but the levelling off of the population could be explained by faltering lemming cycles alone. Lemmings have long been known to affect population productivity of Arctic-nesting migratory birds and, more recently, possibly population dynamics of resident bird species, but this is the first evidence for effects of lemming abundance on population size of a migratory bird species. Why lemming cycles are faltering in the last two decades is unclear, but this may be associated with changes in winter climate at Taimyr Peninsula (Siberia). © 2013 The Authors. Journal of Animal Ecology © 2013 British Ecological Society.

Effects of Clonal Reproduction on Evolutionary Lag and Evolutionary Rescue.

PubMed

Orive, Maria E; Barfield, Michael; Fernandez, Carlos; Holt, Robert D

2017-10-01

Evolutionary lag-the difference between mean and optimal phenotype in the current environment-is of keen interest in light of rapid environmental change. Many ecologically important organisms have life histories that include stage structure and both sexual and clonal reproduction, yet how stage structure and clonality interplay to govern a population's rate of evolution and evolutionary lag is unknown. Effects of clonal reproduction on mean phenotype partition into two portions: one that is phenotype dependent, and another that is genotype dependent. This partitioning is governed by the association between the nonadditive genetic plus random environmental component of phenotype of clonal offspring and their parents. While clonality slows phenotypic evolution toward an optimum, it can dramatically increase population survival after a sudden step change in optimal phenotype. Increased adult survival slows phenotypic evolution but facilitates population survival after a step change; this positive effect can, however, be lost given survival-fecundity trade-offs. Simulations indicate that the benefits of increased clonality under environmental change greatly depend on the nature of that change: increasing population persistence under a step change while decreasing population persistence under a continuous linear change requiring de novo variation. The impact of clonality on the probability of persistence for species in a changing world is thus inexorably linked to the temporal texture of the change they experience.

Population dynamics and climate change: what are the links?

PubMed

Stephenson, Judith; Newman, Karen; Mayhew, Susannah

2010-06-01

Climate change has been described as the biggest global health threat of the 21(st) century. World population is projected to reach 9.1 billion by 2050, with most of this growth in developing countries. While the principal cause of climate change is high consumption in the developed countries, its impact will be greatest on people in the developing world. Climate change and population can be linked through adaptation (reducing vulnerability to the adverse effects of climate change) and, more controversially, through mitigation (reducing the greenhouse gases that cause climate change). The contribution of low-income, high-fertility countries to global carbon emissions has been negligible to date, but is increasing with the economic development that they need to reduce poverty. Rapid population growth endangers human development, provision of basic services and poverty eradication and weakens the capacity of poor communities to adapt to climate change. Significant mass migration is likely to occur in response to climate change and should be regarded as a legitimate response to the effects of climate change. Linking population dynamics with climate change is a sensitive issue, but family planning programmes that respect and protect human rights can bring a remarkable range of benefits. Population dynamics have not been integrated systematically into climate change science. The contribution of population growth, migration, urbanization, ageing and household composition to mitigation and adaptation programmes needs urgent investigation.

Patterns and biases in climate change research on amphibians and reptiles: a systematic review.

PubMed

Winter, Maiken; Fiedler, Wolfgang; Hochachka, Wesley M; Koehncke, Arnulf; Meiri, Shai; De la Riva, Ignacio

2016-09-01

Climate change probably has severe impacts on animal populations, but demonstrating a causal link can be difficult because of potential influences by additional factors. Assessing global impacts of climate change effects may also be hampered by narrow taxonomic and geographical research foci. We review studies on the effects of climate change on populations of amphibians and reptiles to assess climate change effects and potential biases associated with the body of work that has been conducted within the last decade. We use data from 104 studies regarding the effect of climate on 313 species, from 464 species-study combinations. Climate change effects were reported in 65% of studies. Climate change was identified as causing population declines or range restrictions in half of the cases. The probability of identifying an effect of climate change varied among regions, taxa and research methods. Climatic effects were equally prevalent in studies exclusively investigating climate factors (more than 50% of studies) and in studies including additional factors, thus bolstering confidence in the results of studies exclusively examining effects of climate change. Our analyses reveal biases with respect to geography, taxonomy and research question, making global conclusions impossible. Additional research should focus on under-represented regions, taxa and questions. Conservation and climate policy should consider the documented harm climate change causes reptiles and amphibians.

The effects of country-level population policy for enhancing adaptation to climate change

NASA Astrophysics Data System (ADS)

Gunasekara, N. K.; Kazama, S.; Yamazaki, D.; Oki, T.

2012-08-01

The effectiveness of population policy scenarios in reducing the combined impacts of population change and climate change on water resources is explored. One no-policy scenario and two scenarios with population policy assumptions are employed in combination with water availability under the SRES scenarios A1b, B1 and A2 for the impact analysis. The population data used are from the World Bank. The river discharges per grid of horizontal resolution 0.5° are obtained from the Total Runoff Integrating Pathways (TRIP) of the University of Tokyo, Japan. Unlike the population scenarios utilized in the SRES emission scenarios and the newest Representative Concentration Pathways, the scenarios employed in this research are based, even after 2050, on country-level rather than regional growth assumptions. Our analysis implies that in combination with a more heterogeneous pattern of population changes across the world, a more convergent, environmentally friendly emissions scenario, such as B1, can result in a high-impact climate scenario, similar to A2, for the already water-stressed low latitudes. However, the effect of population change supersedes the changes in the climate scenarios. In 2100, Africa, Middle-East and parts of Asia are in extreme water-stress under all scenarios. For countries with high population momentum, the population policy scenario with fertility-reduction assumptions gained a maximum of 6.1 times the water availability in Niger and 5.3 times that in Uganda compared with the no-policy scenario. Most of these countries are in Sub-Saharan Africa. These countries represent 24.5% of the global population in the no-policy scenario and the scenario with fertility- reduction assumptions reduces it to 8.7% by 2100. This scenario is also effective at reducing the area under extreme water stress in these countries. However, the policy scenario with assumptions of population stabilization at the replacement fertility rate increases the water stress in high-latitude countries. Nevertheless, the impact is low due to the high per capita water availability in the region. This research is expected to widen the understanding of the combined impacts of climate change in the future and of the strategies needed to enhance the space for adaptation.

Portfolio effects, climate change, and the persistence of small populations: analyses on the rare plant Saussurea weberi.

PubMed

Abbott, Ronald E; Doak, Daniel F; Peterson, Megan L

2017-04-01

The mechanisms that stabilize small populations in the face of environmental variation are crucial to their long-term persistence. Building from diversity-stability concepts in community ecology, within-population diversity is gaining attention as an important component of population stability. Genetic and microhabitat variation within populations can generate diverse responses to common environmental fluctuations, dampening temporal variability across the population as a whole through portfolio effects. Yet, the potential for portfolio effects to operate at small scales within populations or to change with systematic environmental shifts, such as climate change, remain largely unexplored. We tracked the abundance of a rare alpine perennial plant, Saussurea weberi, in 49 1-m 2 plots within a single population over 20 yr. We estimated among-plot correlations in log annual growth rate to test for population-level synchrony and quantify portfolio effects across the 20-yr study period and also in 5-yr subsets based on June temperature quartiles. Asynchrony among plots, due to different plot-level responses to June temperature, reduced overall fluctuations in abundance and the probability of decline in population models, even when accounting for the effects of density dependence on dynamics. However, plots became more synchronous and portfolio effects decreased during the warmest years of the study, suggesting that future climate warming may erode stabilizing mechanisms in populations of this rare plant. © 2017 by the Ecological Society of America.

Projecting the future of an alpine ungulate under climate change scenarios.

PubMed

White, Kevin S; Gregovich, David P; Levi, Taal

2018-03-01

Climate change represents a primary threat to species persistence and biodiversity at a global scale. Cold adapted alpine species are especially sensitive to climate change and can offer key "early warning signs" about deleterious effects of predicted change. Among mountain ungulates, survival, a key determinant of demographic performance, may be influenced by future climate in complex, and possibly opposing ways. Demographic data collected from 447 mountain goats in 10 coastal Alaska, USA, populations over a 37-year time span indicated that survival is highest during low snowfall winters and cool summers. However, general circulation models (GCMs) predict future increase in summer temperature and decline in winter snowfall. To disentangle how these opposing climate-driven effects influence mountain goat populations, we developed an age-structured population model to project mountain goat population trajectories for 10 different GCM/emissions scenarios relevant for coastal Alaska. Projected increases in summer temperature had stronger negative effects on population trajectories than the positive demographic effects of reduced winter snowfall. In 5 of the 10 GCM/representative concentration pathway (RCP) scenarios, the net effect of projected climate change was extinction over a 70-year time window (2015-2085); smaller initial populations were more likely to go extinct faster than larger populations. Using a resource selection modeling approach, we determined that distributional shifts to higher elevation (i.e., "thermoneutral") summer range was unlikely to be a viable behavioral adaptation strategy; due to the conical shape of mountains, summer range was expected to decline by 17%-86% for 7 of the 10 GCM/RCP scenarios. Projected declines of mountain goat populations are driven by climate-linked bottom-up mechanisms and may have wide ranging implications for alpine ecosystems. These analyses elucidate how projected climate change can negatively alter population dynamics of a sentinel alpine species and provide insight into how demographic modeling can be used to assess risk to species persistence. © 2017 John Wiley & Sons Ltd.

Climate change can alter predator-prey dynamics and population viability of prey.

PubMed

Bastille-Rousseau, Guillaume; Schaefer, James A; Peers, Michael J L; Ellington, E Hance; Mumma, Matthew A; Rayl, Nathaniel D; Mahoney, Shane P; Murray, Dennis L

2018-01-01

For many organisms, climate change can directly drive population declines, but it is less clear how such variation may influence populations indirectly through modified biotic interactions. For instance, how will climate change alter complex, multi-species relationships that are modulated by climatic variation and that underlie ecosystem-level processes? Caribou (Rangifer tarandus), a keystone species in Newfoundland, Canada, provides a useful model for unravelling potential and complex long-term implications of climate change on biotic interactions and population change. We measured cause-specific caribou calf predation (1990-2013) in Newfoundland relative to seasonal weather patterns. We show that black bear (Ursus americanus) predation is facilitated by time-lagged higher summer growing degree days, whereas coyote (Canis latrans) predation increases with current precipitation and winter temperature. Based on future climate forecasts for the region, we illustrate that, through time, coyote predation on caribou calves could become increasingly important, whereas the influence of black bear would remain unchanged. From these predictions, demographic projections for caribou suggest long-term population limitation specifically through indirect effects of climate change on calf predation rates by coyotes. While our work assumes limited impact of climate change on other processes, it illustrates the range of impact that climate change can have on predator-prey interactions. We conclude that future efforts to predict potential effects of climate change on populations and ecosystems should include assessment of both direct and indirect effects, including climate-predator interactions.

Potential distribution of dengue fever under scenarios of climate change and economic development.

PubMed

Aström, Christofer; Rocklöv, Joacim; Hales, Simon; Béguin, Andreas; Louis, Valerie; Sauerborn, Rainer

2012-12-01

Dengue fever is the most important viral vector-borne disease with ~50 million cases per year globally. Previous estimates of the potential effect of global climate change on the distribution of vector-borne disease have not incorporated the effect of socioeconomic factors, which may have biased the results. We describe an empirical model of the current geographic distribution of dengue, based on the independent effects of climate and gross domestic product per capita (GDPpc, a proxy for socioeconomic development). We use the model, along with scenario-based projections of future climate, economic development, and population, to estimate populations at risk of dengue in the year 2050. We find that both climate and GDPpc influence the distribution of dengue. If the global climate changes as projected but GDPpc remained constant, the population at risk of dengue is estimated to increase by about 0.28 billion in 2050. However, if both climate and GDPpc change as projected, we estimate a decrease of 0.12 billion in the population at risk of dengue in 2050. Empirically, the geographic distribution of dengue is strongly dependent on both climatic and socioeconomic variables. Under a scenario of constant GDPpc, global climate change results in a modest but important increase in the global population at risk of dengue. Under scenarios of high GDPpc, this adverse effect of climate change is counteracted by the beneficial effect of socioeconomic development.

Local interactions lead to pathogen-driven change to host population dynamics.

PubMed

Boots, Michael; Childs, Dylan; Reuman, Daniel C; Mealor, Michael

2009-10-13

Individuals tend to interact more strongly with nearby individuals or within particular social groups. Recent theoretical advances have demonstrated that these within-population relationships can have fundamental implications for ecological and evolutionary dynamics. In particular, contact networks are crucial to the spread and evolution of disease. However, the theory remains largely untested experimentally. Here, we manipulate habitat viscosity and thereby the frequency of local interactions in an insect-pathogen model system in which the virus had previously been shown to have little effect on host population dynamics. At high viscosity, the pathogen caused the collapse of dominant and otherwise stable host generation cycles. Modeling shows that this collapse can be explained by an increase in the frequency of intracohort interactions relative to intercohort interactions, leading to more disease transmission. Our work emphasizes that spatial structure can subtly mediate intraspecific competition and the effects of natural enemies. A decrease in dispersal in a population may actually (sometimes rather counterintuitively) intensify the effects of parasites. Broadly, because anthropological and environmental change often cause changes in population mixing, our work highlights the potential for dramatic changes in the effects of parasites on host populations.

Reduced Genetic Diversity and Increased Structure in American Mink on the Swedish Coast following Invasive Species Control.

PubMed

Zalewski, Andrzej; Zalewska, Hanna; Lunneryd, Sven-Gunnar; André, Carl; Mikusiński, Grzegorz

2016-01-01

Eradication and population reductions are often used to mitigate the negative impacts of non-native invasive species on native biodiversity. However, monitoring the effectiveness of non-native species control programmes is necessary to evaluate the efficacy of these measures. Genetic monitoring could provide valuable insights into temporal changes in demographic, ecological, and evolutionary processes in invasive populations being subject to control programmes. Such programmes should cause a decrease in effective population size and/or in genetic diversity of the targeted non-native species and an increase in population genetic structuring over time. We used microsatellite DNA data from American mink (Neovison vison) to determine whether the removal of this predator on the Koster Islands archipelago and the nearby Swedish mainland affected genetic variation over six consecutive years of mink culling by trappers as part of a population control programme. We found that on Koster Islands allelic richness decreased (from on average 4.53 to 3.55), genetic structuring increased, and effective population size did not change. In contrast, the mink population from the Swedish coast showed no changes in genetic diversity or structure, suggesting the stability of this population over 6 years of culling. Effective population size did not change over time but was higher on the coast than on the islands across all years. Migration rates from the islands to the coast were almost two times higher than from the coast to the islands. Most migrants leaving the coast were localised on the southern edge of the archipelago, as expected from the direction of the sea current between the two sites. Genetic monitoring provided valuable information on temporal changes in the population of American mink suggesting that this approach can be used to evaluate and improve control programmes of invasive vertebrates.

Why a macroeconomic perspective is critical to the prevention of noncommunicable disease.

PubMed

Smith, Richard

2012-09-21

Effective prevention of noncommunicable diseases will require changes in how we live, and thereby effect important economic changes across populations, sectors, and countries. What we do not know is which populations, sectors, or countries will be positively or negatively affected by such changes, nor by how much. Without this information we cannot know which policies will produce effects that are beneficial both for economies and for health.

What Is a Mild Winter? Regional Differences in Within-Species Responses to Climate Change.

PubMed

Vetter, Sebastian G; Ruf, Thomas; Bieber, Claudia; Arnold, Walter

2015-01-01

Climate change is known to affect ecosystems globally, but our knowledge of its impact on large and widespread mammals, and possibly population-specific responses is still sparse. We investigated large-scale and long-term effects of climate change on local population dynamics using the wild boar (Sus scrofa L.) as a model species. Our results show that population increases across Europe are strongly associated with increasingly mild winters, yet with region-specific threshold temperatures for the onset of exponential growth. Additionally, we found that abundant availability of critical food resources, e.g. beech nuts, can outweigh the negative effects of cold winters on population growth of wild boar. Availability of beech nuts is highly variable and highest in years of beech mast which increased in frequency since 1980, according to our data. We conclude that climate change drives population growth of wild boar directly by relaxing the negative effect of cold winters on survival and reproduction, and indirectly by increasing food availability. However, region-specific responses need to be considered in order to fully understand a species' demographic response to climate change.

Evaluating growth of the Porcupine Caribou Herd using a stochastic model

USGS Publications Warehouse

Walsh, Noreen E.; Griffith, Brad; McCabe, Thomas R.

1995-01-01

Estimates of the relative effects of demographic parameters on population rates of change, and of the level of natural variation in these parameters, are necessary to address potential effects of perturbations on populations. We used a stochastic model, based on survival and reproduction estimates of the Porcupine Caribou (Rangifer tarandus granti) Herd (PCH), during 1983-89 and 1989-92 to obtain distributions of potential population rates of change (r). The distribution of r produced by 1,000 trajectories of our simulation model (1983-89, r̄ = 0.013; 1989-92, r̄ = 0.003) encompassed the rate of increase calculated from an independent series of photo-survey data over the same years (1983-89, r = 0.048; 1989-92, r = -0.035). Changes in adult female survival had the largest effect on r, followed by changes in calf survival. We hypothesized that petroleum development on calving grounds, or changes in calving and post-calving habitats due to global climate change, would affect model input parameters. A decline in annual adult female survival from 0.871 to 0.847, or a decline in annual calf survival from 0.518 to 0.472, would be sufficient to cause a declining population, if all other input estimates remained the same. We then used these lower survival rates, in conjunction with our estimated amount of among-year variation, to determine a range of resulting population trajectories. Stochastic models can be used to better understand dynamics of populations, optimize sampling investment, and evaluate potential effects of various factors on population growth.

Climate warming alters effects of management on population viability of threatened species: results from a 30-year experimental study on a rare orchid.

PubMed

Sletvold, Nina; Dahlgren, Johan P; Oien, Dag-Inge; Moen, Asbjørn; Ehrlén, Johan

2013-09-01

Climate change is expected to influence the viability of populations both directly and indirectly, via species interactions. The effects of large-scale climate change are also likely to interact with local habitat conditions. Management actions designed to preserve threatened species therefore need to adapt both to the prevailing climate and local conditions. Yet, few studies have separated the direct and indirect effects of climatic variables on the viability of local populations and discussed the implications for optimal management. We used 30 years of demographic data to estimate the simultaneous effects of management practice and among-year variation in four climatic variables on individual survival, growth and fecundity in one coastal and one inland population of the perennial orchid Dactylorhiza lapponica in Norway. Current management, mowing, is expected to reduce competitive interactions. Statistical models of how climate and management practice influenced vital rates were incorporated into matrix population models to quantify effects on population growth rate. Effects of climate differed between mown and control plots in both populations. In particular, population growth rate increased more strongly with summer temperature in mown plots than in control plots. Population growth rate declined with spring temperature in the inland population, and with precipitation in the coastal population, and the decline was stronger in control plots in both populations. These results illustrate that both direct and indirect effects of climate change are important for population viability and that net effects depend both on local abiotic conditions and on biotic conditions in terms of management practice and intensity of competition. The results also show that effects of management practices influencing competitive interactions can strongly depend on climatic factors. We conclude that interactions between climate and management should be considered to reliably predict future population viability and optimize conservation actions. © 2013 John Wiley & Sons Ltd.

Effects of economic crises on population health outcomes in Latin America, 1981–2010: an ecological study

PubMed Central

Williams, Callum; Gilbert, Barnabas James; Zeltner, Thomas; Watkins, Johnathan; Atun, Rifat; Maruthappu, Mahiben

2016-01-01

Objectives The relative health effects of changes in unemployment, inflation and gross domestic product (GDP) per capita on population health have not been assessed. We aimed to determine the effect of changes in these economic measures on mortality metrics across Latin America. Design Ecological study. Setting Latin America (21 countries), 1981–2010. Outcome measures Uses multivariate regression analysis to assess the effects of changes in unemployment, inflation and GDP per capita on 5 mortality indicators across 21 countries in Latin America, 1981–2010. Country-specific differences in healthcare infrastructure, population structure and population size were controlled for. Results Between 1981 and 2010, a 1% rise in unemployment was associated with statistically significant deteriorations (p<0.05) in 5 population health outcomes, with largest deteriorations in 1–5 years of age and male adult mortality rates (1.14 and 0.53 rises per 1000 deaths respectively). A 1% rise in inflation rate was associated with significant deteriorations (p<0.05) in 4 population health outcomes, with the largest deterioration in male adult mortality rate (0.0033 rise per 1000 deaths). Lag analysis showed that 5 years after rises in unemployment and inflation, significant deteriorations (p<0.05) occurred in 3 and 5 mortality metrics, respectively. A 1% rise in GDP per capita was associated with no significant deteriorations in population health outcomes either in the short or long term. β coefficient comparisons indicated that the effect of unemployment increases was substantially greater than that of changes in GDP per capita or inflation. Conclusions Rises in unemployment and inflation are associated with long-lasting deteriorations in several population health outcomes. Unemployment exerted much larger effects on health than inflation. In contrast, changes in GDP per capita had almost no association with the explored health outcomes. Contrary to neoclassical development economics, policymakers should prioritise amelioration of unemployment if population health outcomes are to be optimised. PMID:26739715

Effect of population growth on changes in the agrarian structure of rural Bangladesh.

PubMed

Chaudhury, R H

1981-01-01

The author examines available information on the effect of population growth on the agrarian structure of Bangladesh. Trends and patterns of land distribution over time are reviewed. The effects of changes in land distribution on productivity are investigated, and the relationship between family size and land ownership is analyzed.

Predicting population survival under future climate change: density dependence, drought and extraction in an insular bighorn sheep.

PubMed

Colchero, Fernando; Medellin, Rodrigo A; Clark, James S; Lee, Raymond; Katul, Gabriel G

2009-05-01

1. Our understanding of the interplay between density dependence, climatic perturbations, and conservation practices on the dynamics of small populations is still limited. This can result in uninformed strategies that put endangered populations at risk. Moreover, the data available for a large number of populations in such circumstances are sparse and mined with missing data. Under the current climate change scenarios, it is essential to develop appropriate inferential methods that can make use of such data sets. 2. We studied a population of desert bighorn sheep introduced to Tiburon Island, Mexico in 1975 and subjected to irregular extractions for the last 10 years. The unique attributes of this population are absence of predation and disease, thereby permitting us to explore the combined effect of density dependence, environmental variability and extraction in a 'controlled setting.' Using a combination of nonlinear discrete models with long-term field data, we constructed three basic Bayesian state space models with increasing density dependence (DD), and the same three models with the addition of summer drought effects. 3. We subsequently used Monte Carlo simulations to evaluate the combined effect of drought, DD, and increasing extractions on the probability of population survival under two climate change scenarios (based on the Intergovernmental Panel on Climate Change predictions): (i) increase in drought variability; and (ii) increase in mean drought severity. 4. The population grew from 16 individuals introduced in 1975 to close to 700 by 1993. Our results show that the population's growth was dominated by DD, with drought having a secondary but still relevant effect on its dynamics. 5. Our predictions suggest that under climate change scenario (i), extraction dominates the fate of the population, while for scenario (ii), an increase in mean drought affects the population's probability of survival in an equivalent magnitude as extractions. Thus, for the long-term survival of the population, our results stress that a more variable environment is less threatening than one in which the mean conditions become harsher. Current climate change scenarios and their underlying uncertainty make studies such as this one crucial for understanding the dynamics of ungulate populations and their conservation.

CHANGES IN SEX RATIO AT BIRTH IN CHINA: A DECOMPOSITION BY BIRTH ORDER.

PubMed

Jiang, Quanbao; Yu, Qun; Yang, Shucai; Sánchez-Barricarte, Jesús J

2017-11-01

The long-term high sex ratio at birth (SRB) is a serious issue in China. In this study, changes in SRB were decomposed into variations in SRB by birth order and compositional changes in female births by birth order. With SRB data from China's surveys and censuses, and SRB data from South Korea's vital registration and censuses from 1980-2015, the trend and decomposition results in SRB were compared between China and South Korea, and the decomposition results for urban and rural SRBs, and for provinces, are presented. In both China and South Korea the rise in the SRB was driven by a rise in the SRB at all birth orders, which was only partly counteracted by the change in the distribution of births by order. The overall rise in the SRB ended when there was a decline in the SRB at second birth or above in South Korea. In China the total effect of variations in SRB of all birth orders increased more for the rural population than for the urban population before 2000, resulting in a higher total SRB for rural than urban population. After 2000, the total effect of variations in SRB of all birth orders lowered the total SRB for the rural population, whereas the effect of compositional change increased the total SRB, leading to a very slight rise in the total SRB for the rural population. At the province level, there was no spatial autocorrelation for the changes in total SRB by province, the total effect of variations in SRB of all birth orders or the effect of compositional change. The effect of variations in SRB by birth order accounted for the majority of changes in total SRB in most provinces.

The effects of hurricanes on birds, with special reference to Caribbean islands

USGS Publications Warehouse

Wiley, J.W.; Wunderle, J.M.

1993-01-01

Cyclonic storms, variously called typhoons, cyclones, or hurricanes (henceforth, hurricanes), are common in many parts of the world, where their frequent occurrence can have both direct and indirect effects on bird populations. Direct effects of hurricanes include mortality from exposure to hurricane winds, rains, and storm surges, and geographic displacement of individuals by storm winds. Indirect effects become apparent in the storm's aftermath and include loss of food supplies or foraging substrates; loss of nests and nest or roost sites; increased vulnerability to predation; microclimate changes; and increased conflict with humans. The short-term response of bird populations to hurricane damage, before changes in plant succession, includes shifts in diet, foraging sites or habitats, and reproductive changes. Bird populations may show long-term responses to changes in plant succession as second-growth vegetation increases in storm-damaged old-growth forests. The greatest stress of a hurricane to most upland terrestrial bird populations occurs after its passage rather than during its impact. The most important effect of a hurricane is the destruction of vegetation, which secondarily affects wildlife in the storm's aftermath. The most vulnerable terrestrial wildlife populations have a diet of nectar, fruit, or seeds; nest, roost, or forage on large old trees; require a closed forest canopy; have special microclimate requirements and/or live in a habitat in which vegetation has a slow recovery rate. Small populations with these traits are at greatest risk to hurricane-induced extinction, particularly if they exist in small isolated habitat fragments. Recovery of avian populations from hurricane effects is partially dependent on the extent and degree of vegetation damage as well as its rate of recovery. Also, the reproductive rate of the remnant local population and recruitment from undisturbed habitat patches influence the rate at which wildlife populations recover from damage.

Population exposure to heat-related extremes: Demographic change vs climate change

NASA Astrophysics Data System (ADS)

Jones, B.; O'Neill, B. C.; Tebaldi, C.; Oleson, K. W.

2014-12-01

Extreme heat events are projected to increase in frequency and intensity in the coming decades [1]. The physical effects of extreme heat on human populations are well-documented, and anticipating changes in future exposure to extreme heat is a key component of adequate planning/mitigation [2, 3]. Exposure to extreme heat depends not only on changing climate, but also on changes in the size and spatial distribution of the human population. Here we focus on systematically quantifying exposure to extreme heat as a function of both climate and population change. We compare exposure outcomes across multiple global climate and spatial population scenarios, and characterize the relative contributions of each to population exposure to extreme heat. We consider a 2 x 2 matrix of climate and population output, using projections of heat extremes corresponding to RCP 4.5 and RCP 8.5 from the NCAR community land model, and spatial population projections for SSP 3 and SSP 5 from the NCAR spatial population downscaling model. Our primary comparison is across RCPs - exposure outcomes from RCP 4.5 versus RCP 8.5 - paying particular attention to how variation depends on the choice of SSP in terms of aggregate global and regional exposure, as well as the spatial distribution of exposure. We assess how aggregate exposure changes based on the choice of SSP, and which driver is more important, population or climate change (i.e. does that outcome vary more as a result of RCP or SSP). We further decompose the population component to analyze the contributions of total population change, migration, and changes in local spatial structure. Preliminary results from a similar study of the US suggests a four-to-six fold increase in total exposure by the latter half of the 21st century. Changes in population are as important as changes in climate in driving this outcome, and there is regional variation in the relative importance of each. Aggregate population growth, as well as redistribution of the population across larger US regions, strongly affects outcomes while smaller-scale spatial patterns of population change have smaller effects. [1] Collins, M. et al. (2013) Contribution of WG I to the 5th AR of the IPCC[2] Romero-Lankao, P. et al (2014) Contribution of WG II to the 5th AR of the IPCC[3] Walsh, J. et al. (2014) The 3rd National Climate Assessment

Population connectivity and genetic diversity of American marten (Martes americana) in the United States northern Rocky Mountains in a climate change context

Treesearch

Tzeidle N. Wasserman; Samuel A. Cushman; Jeremy S. Littell; Andrew J. Shirk; Erin L. Landguth

2013-01-01

Climate change is likely to alter population connectivity, particularly for species associated with higher elevation environments. The goal of this study is to predict the potential effects of future climate change on population connectivity and genetic diversity of American marten populations across a 30.2 million hectare region of the in the US northern Rocky...

Parsing demographic effects of canine pParvovirus on a Minnesota wolf population

USGS Publications Warehouse

Mech, L. David; Goyal, Sagar M.

2011-01-01

We examined 35 years of relationships among wolf (Canis lupus) pup survival, population change and canine parvovirus (CPV) seroprevalence in Northeastern Minnesota to determine when CPV exerted its strongest effects. Using correlation analysis of data from five periods of 7-years each from 1973 through 2007, we learned that the strongest effect of CPV on pup survival (r = -0.73) and on wolf population change (r = -0.92) was during 1987 to 1993. After that, little effect was documented despite a mean CPV seroprevalence from 1994 of 2007 of 70.8% compared with 52.6% during 1987 to 1993. We conclude that after CPV became endemic and produced its peak effect on the study population, that population developed enough immunity to withstand the disease.

Predicting the effects of climate change on population connectivity and genetic diversity of an imperiled freshwater mussel, Cumberlandia monodonta (Bivalvia: Margaritiferidae), in riverine systems.

PubMed

Inoue, Kentaro; Berg, David J

2017-01-01

In the face of global climate change, organisms may respond to temperature increases by shifting their ranges poleward or to higher altitudes. However, the direction of range shifts in riverine systems is less clear. Because rivers are dendritic networks, there is only one dispersal route from any given location to another. Thus, range shifts are only possible if branches are connected by suitable habitat, and stream-dwelling organisms can disperse through these branches. We used Cumberlandia monodonta (Bivalvia: Unionoida: Margaritiferidae) as a model species to investigate the effects of climate change on population connectivity because a majority of contemporary populations are panmictic. We combined ecological niche models (ENMs) with population genetic simulations to investigate the effects of climate change on population connectivity and genetic diversity of C. monodonta. The ENMs were constructed using bioclimatic and landscape data to project shifts in suitable habitat under future climate scenarios. We then used forward-time simulations to project potential changes in genetic diversity and population connectivity based on these range shifts. ENM results under current conditions indicated long stretches of highly suitable habitat in rivers where C. monodonta persists; populations in the upper Mississippi River remain connected by suitable habitat that does not impede gene flow. Future climate scenarios projected northward and headwater-ward range contraction and drastic declines in habitat suitability for most extant populations throughout the Mississippi River Basin. Simulations indicated that climate change would greatly reduce genetic diversity and connectivity across populations. Results suggest that a single, large population of C. monodonta will become further fragmented into smaller populations, each of which will be isolated and begin to differentiate genetically. Because C. monodonta is a widely distributed species and purely aquatic, our results suggest that persistence and connectivity of stream-dwelling organisms will be significantly altered in response to future climate change. © 2016 John Wiley & Sons Ltd.

Modeling Climate Change and Sturgeon Populations in the Missouri River

USGS Publications Warehouse

Wildhaber, Mark L.

2010-01-01

The U.S. Geological Survey (USGS) Columbia Environmental Research Center (CERC), in collaboration with researchers from the University of Missouri and Iowa State University, is conducting research to address effects of climate change on sturgeon populations (Scaphirhynchus spp.) in the Missouri River. The CERC is conducting laboratory, field, and modeling research to identify causative factors for the responses of fish populations to natural and human-induced environmental changes and using this information to understand sensitivity of sturgeon populations to potential climate change in the Missouri River drainage basin. Sturgeon response information is being used to parameterize models predicting future population trends. These models will provide a set of tools for natural resource managers to assess management strategies in the context of global climate change. This research complements and builds on the ongoing Comprehensive Sturgeon Research Program (CSRP) at the CERC. The CSRP is designed to provide information critical to restoration of the Missouri River ecosystem and the endangered pallid sturgeon (S. albus). Current research is being funded by USGS through the National Climate Change Wildlife Science Center (NCCWSC) and the Science Support Partnership (SSP) Program that is held by the USGS and the U.S. Fish and Wildlife Service. The national mission of the NCCWSC is to improve the capacity of fish and wildlife agencies to respond to climate change and to address high-priority climate change effects on fish and wildlife. Within the national context, the NCCWSC research on the Missouri River focuses on temporal and spatial downscaling and associated uncertainty in modeling climate change effects on sturgeon species in the Missouri River. The SSP research focuses on improving survival and population estimates for pallid sturgeon population models.

Patterns and biases in climate change research on amphibians and reptiles: a systematic review

PubMed Central

2016-01-01

Climate change probably has severe impacts on animal populations, but demonstrating a causal link can be difficult because of potential influences by additional factors. Assessing global impacts of climate change effects may also be hampered by narrow taxonomic and geographical research foci. We review studies on the effects of climate change on populations of amphibians and reptiles to assess climate change effects and potential biases associated with the body of work that has been conducted within the last decade. We use data from 104 studies regarding the effect of climate on 313 species, from 464 species–study combinations. Climate change effects were reported in 65% of studies. Climate change was identified as causing population declines or range restrictions in half of the cases. The probability of identifying an effect of climate change varied among regions, taxa and research methods. Climatic effects were equally prevalent in studies exclusively investigating climate factors (more than 50% of studies) and in studies including additional factors, thus bolstering confidence in the results of studies exclusively examining effects of climate change. Our analyses reveal biases with respect to geography, taxonomy and research question, making global conclusions impossible. Additional research should focus on under-represented regions, taxa and questions. Conservation and climate policy should consider the documented harm climate change causes reptiles and amphibians. PMID:27703684

Assessing multi-taxa sensitivity to the human footprint, habitat fragmentation and loss by exploring alternative scenarios of dispersal ability and population size: A simulation approach

Treesearch

Brian K. Hand; Samuel A. Cushman; Erin L. Landguth; John Lucotch

2014-01-01

Quantifying the effects of landscape change on population connectivity is compounded by uncertainties about population size and distribution and a limited understanding of dispersal ability for most species. In addition, the effects of anthropogenic landscape change and sensitivity to regional climatic conditions interact to strongly affect habitat...

Population-dependent effects of ocean acidification.

PubMed

Wood, Hannah L; Sundell, Kristina; Almroth, Bethanie Carney; Sköld, Helén Nilsson; Eriksson, Susanne P

2016-04-13

Elevated carbon dioxide levels and the resultant ocean acidification (OA) are changing the abiotic conditions of the oceans at a greater rate than ever before and placing pressure on marine species. Understanding the response of marine fauna to this change is critical for understanding the effects of OA. Population-level variation in OA tolerance is highly relevant and important in the determination of ecosystem resilience and persistence, but has received little focus to date. In this study, whether OA has the same biological consequences in high-salinity-acclimated population versus a low-salinity-acclimated population of the same species was investigated in the marine isopod Idotea balthica.The populations were found to have physiologically different responses to OA. While survival rate was similar between the two study populations at a future CO2 level of 1000 ppm, and both populations showed increased oxidative stress, the metabolic rate and osmoregulatory activity differed significantly between the two populations. The results of this study demonstrate that the physiological response to OA of populations from different salinities can vary. Population-level variation and the environment provenance of individuals used in OA experiments should be taken into account for the evaluation and prediction of climate change effects. © 2016 The Author(s).

Population-dependent effects of ocean acidification

PubMed Central

Wood, Hannah L.; Sundell, Kristina; Almroth, Bethanie Carney; Sköld, Helén Nilsson; Eriksson, Susanne P.

2016-01-01

Elevated carbon dioxide levels and the resultant ocean acidification (OA) are changing the abiotic conditions of the oceans at a greater rate than ever before and placing pressure on marine species. Understanding the response of marine fauna to this change is critical for understanding the effects of OA. Population-level variation in OA tolerance is highly relevant and important in the determination of ecosystem resilience and persistence, but has received little focus to date. In this study, whether OA has the same biological consequences in high-salinity-acclimated population versus a low-salinity-acclimated population of the same species was investigated in the marine isopod Idotea balthica. The populations were found to have physiologically different responses to OA. While survival rate was similar between the two study populations at a future CO2 level of 1000 ppm, and both populations showed increased oxidative stress, the metabolic rate and osmoregulatory activity differed significantly between the two populations. The results of this study demonstrate that the physiological response to OA of populations from different salinities can vary. Population-level variation and the environment provenance of individuals used in OA experiments should be taken into account for the evaluation and prediction of climate change effects. PMID:27053741

Cross-realm assessment of climate change impacts on species' abundance trends.

PubMed

Bowler, Diana E; Hof, Christian; Haase, Peter; Kröncke, Ingrid; Schweiger, Oliver; Adrian, Rita; Baert, Léon; Bauer, Hans-Günther; Blick, Theo; Brooker, Rob W; Dekoninck, Wouter; Domisch, Sami; Eckmann, Reiner; Hendrickx, Frederik; Hickler, Thomas; Klotz, Stefan; Kraberg, Alexandra; Kühn, Ingolf; Matesanz, Silvia; Meschede, Angelika; Neumann, Hermann; O'Hara, Robert; Russell, David J; Sell, Anne F; Sonnewald, Moritz; Stoll, Stefan; Sundermann, Andrea; Tackenberg, Oliver; Türkay, Michael; Valladares, Fernando; van Herk, Kok; van Klink, Roel; Vermeulen, Rikjan; Voigtländer, Karin; Wagner, Rüdiger; Welk, Erik; Wiemers, Martin; Wiltshire, Karen H; Böhning-Gaese, Katrin

2017-02-17

Climate change, land-use change, pollution and exploitation are among the main drivers of species' population trends; however, their relative importance is much debated. We used a unique collection of over 1,000 local population time series in 22 communities across terrestrial, freshwater and marine realms within central Europe to compare the impacts of long-term temperature change and other environmental drivers from 1980 onwards. To disentangle different drivers, we related species' population trends to species- and driver-specific attributes, such as temperature and habitat preference or pollution tolerance. We found a consistent impact of temperature change on the local abundances of terrestrial species. Populations of warm-dwelling species increased more than those of cold-dwelling species. In contrast, impacts of temperature change on aquatic species' abundances were variable. Effects of temperature preference were more consistent in terrestrial communities than effects of habitat preference, suggesting that the impacts of temperature change have become widespread for recent changes in abundance within many terrestrial communities of central Europe.

Local Variability Mediates Vulnerability of Trout Populations to Land Use and Climate Change

PubMed Central

Penaluna, Brooke E.; Dunham, Jason B.; Railsback, Steve F.; Arismendi, Ivan; Johnson, Sherri L.; Bilby, Robert E.; Safeeq, Mohammad; Skaugset, Arne E.

2015-01-01

Land use and climate change occur simultaneously around the globe. Fully understanding their separate and combined effects requires a mechanistic understanding at the local scale where their effects are ultimately realized. Here we applied an individual-based model of fish population dynamics to evaluate the role of local stream variability in modifying responses of Coastal Cutthroat Trout (Oncorhynchus clarkii clarkii) to scenarios simulating identical changes in temperature and stream flows linked to forest harvest, climate change, and their combined effects over six decades. We parameterized the model for four neighboring streams located in a forested headwater catchment in northwestern Oregon, USA with multi-year, daily measurements of stream temperature, flow, and turbidity (2007–2011), and field measurements of both instream habitat structure and three years of annual trout population estimates. Model simulations revealed that variability in habitat conditions among streams (depth, available habitat) mediated the effects of forest harvest and climate change. Net effects for most simulated trout responses were different from or less than the sum of their separate scenarios. In some cases, forest harvest countered the effects of climate change through increased summer flow. Climate change most strongly influenced trout (earlier fry emergence, reductions in biomass of older trout, increased biomass of young-of-year), but these changes did not consistently translate into reductions in biomass over time. Forest harvest, in contrast, produced fewer and less consistent responses in trout. Earlier fry emergence driven by climate change was the most consistent simulated response, whereas survival, growth, and biomass were inconsistent. Overall our findings indicate a host of local processes can strongly influence how populations respond to broad scale effects of land use and climate change. PMID:26295478

Local variability mediates vulnerability of trout populations to land use and climate change

USGS Publications Warehouse

Penaluna, Brooke E.; Dunham, Jason B.; Railsback, Steve F.; Arismendi, Ivan; Johnson, Sherri L.; Bilby, Robert E; Safeeq, Mohammad; Skaugset, Arne E.

2015-01-01

Land use and climate change occur simultaneously around the globe. Fully understanding their separate and combined effects requires a mechanistic understanding at the local scale where their effects are ultimately realized. Here we applied an individual-based model of fish population dynamics to evaluate the role of local stream variability in modifying responses of Coastal Cutthroat Trout (Oncorhynchus clarkii clarkii) to scenarios simulating identical changes in temperature and stream flows linked to forest harvest, climate change, and their combined effects over six decades. We parameterized the model for four neighboring streams located in a forested headwater catchment in northwestern Oregon, USA with multi-year, daily measurements of stream temperature, flow, and turbidity (2007–2011), and field measurements of both instream habitat structure and three years of annual trout population estimates. Model simulations revealed that variability in habitat conditions among streams (depth, available habitat) mediated the effects of forest harvest and climate change. Net effects for most simulated trout responses were different from or less than the sum of their separate scenarios. In some cases, forest harvest countered the effects of climate change through increased summer flow. Climate change most strongly influenced trout (earlier fry emergence, reductions in biomass of older trout, increased biomass of young-of-year), but these changes did not consistently translate into reductions in biomass over time. Forest harvest, in contrast, produced fewer and less consistent responses in trout. Earlier fry emergence driven by climate change was the most consistent simulated response, whereas survival, growth, and biomass were inconsistent. Overall our findings indicate a host of local processes can strongly influence how populations respond to broad scale effects of land use and climate change.

Local Variability Mediates Vulnerability of Trout Populations to Land Use and Climate Change.

PubMed

Penaluna, Brooke E; Dunham, Jason B; Railsback, Steve F; Arismendi, Ivan; Johnson, Sherri L; Bilby, Robert E; Safeeq, Mohammad; Skaugset, Arne E

2015-01-01

Land use and climate change occur simultaneously around the globe. Fully understanding their separate and combined effects requires a mechanistic understanding at the local scale where their effects are ultimately realized. Here we applied an individual-based model of fish population dynamics to evaluate the role of local stream variability in modifying responses of Coastal Cutthroat Trout (Oncorhynchus clarkii clarkii) to scenarios simulating identical changes in temperature and stream flows linked to forest harvest, climate change, and their combined effects over six decades. We parameterized the model for four neighboring streams located in a forested headwater catchment in northwestern Oregon, USA with multi-year, daily measurements of stream temperature, flow, and turbidity (2007-2011), and field measurements of both instream habitat structure and three years of annual trout population estimates. Model simulations revealed that variability in habitat conditions among streams (depth, available habitat) mediated the effects of forest harvest and climate change. Net effects for most simulated trout responses were different from or less than the sum of their separate scenarios. In some cases, forest harvest countered the effects of climate change through increased summer flow. Climate change most strongly influenced trout (earlier fry emergence, reductions in biomass of older trout, increased biomass of young-of-year), but these changes did not consistently translate into reductions in biomass over time. Forest harvest, in contrast, produced fewer and less consistent responses in trout. Earlier fry emergence driven by climate change was the most consistent simulated response, whereas survival, growth, and biomass were inconsistent. Overall our findings indicate a host of local processes can strongly influence how populations respond to broad scale effects of land use and climate change.

Decomposing the effect of crime on population changes.

PubMed

Foote, Andrew

2015-04-01

This article estimates the effect of crime on migration rates for counties in U.S. metropolitan areas and makes three contributions to the literature. First, I use administrative data on migration flows between counties, which gives me more precise estimates of population changes than data used in previous studies. Second, I am able to decompose net population changes into gross migration flows in order to identify how individuals respond to crime rate changes. Finally, I include county-level trends so that my identification comes from shocks away from the trend. I find effects that are one-fiftieth the size of the most prominent estimate in the literature; and although the long-run effects are somewhat larger, they are still only approximately one-twentieth as large. I also find that responses to crime rates differ by subgroups, and that increases in crime cause white households to leave the county, with effects almost 10 times as large as for black households.

Future premature mortality due to O3, secondary inorganic aerosols and primary PM in Europe--sensitivity to changes in climate, anthropogenic emissions, population and building stock.

PubMed

Geels, Camilla; Andersson, Camilla; Hänninen, Otto; Lansø, Anne Sofie; Schwarze, Per E; Skjøth, Carsten Ambelas; Brandt, Jørgen

2015-03-04

Air pollution is an important environmental factor associated with health impacts in Europe and considerable resources are used to reduce exposure to air pollution through emission reductions. These reductions will have non-linear effects on exposure due, e.g., to interactions between climate and atmospheric chemistry. By using an integrated assessment model, we quantify the effect of changes in climate, emissions and population demography on exposure and health impacts in Europe. The sensitivity to the changes is assessed by investigating the differences between the decades 2000-2009, 2050-2059 and 2080-2089. We focus on the number of premature deaths related to atmospheric ozone, Secondary Inorganic Aerosols and primary PM. For the Nordic region we furthermore include a projection on how population exposure might develop due to changes in building stock with increased energy efficiency. Reductions in emissions cause a large significant decrease in mortality, while climate effects on chemistry and emissions only affects premature mortality by a few percent. Changes in population demography lead to a larger relative increase in chronic mortality than the relative increase in population. Finally, the projected changes in building stock and infiltration rates in the Nordic indicate that this factor may be very important for assessments of population exposure in the future.

Future Premature Mortality Due to O3, Secondary Inorganic Aerosols and Primary PM in Europe — Sensitivity to Changes in Climate, Anthropogenic Emissions, Population and Building Stock

PubMed Central

Geels, Camilla; Andersson, Camilla; Hänninen, Otto; Lansø, Anne Sofie; Schwarze, Per E.; Ambelas Skjøth, Carsten; Brandt, Jørgen

2015-01-01

Air pollution is an important environmental factor associated with health impacts in Europe and considerable resources are used to reduce exposure to air pollution through emission reductions. These reductions will have non-linear effects on exposure due, e.g., to interactions between climate and atmospheric chemistry. By using an integrated assessment model, we quantify the effect of changes in climate, emissions and population demography on exposure and health impacts in Europe. The sensitivity to the changes is assessed by investigating the differences between the decades 2000–2009, 2050–2059 and 2080–2089. We focus on the number of premature deaths related to atmospheric ozone, Secondary Inorganic Aerosols and primary PM. For the Nordic region we furthermore include a projection on how population exposure might develop due to changes in building stock with increased energy efficiency. Reductions in emissions cause a large significant decrease in mortality, while climate effects on chemistry and emissions only affects premature mortality by a few percent. Changes in population demography lead to a larger relative increase in chronic mortality than the relative increase in population. Finally, the projected changes in building stock and infiltration rates in the Nordic indicate that this factor may be very important for assessments of population exposure in the future. PMID:25749320

Ester Boserup's theory of agrarian change: a critical review.

PubMed

Grigg, D

1979-01-01

As discussions of the positive effect of population growth upon agricutural change have been less common than focus on the negative effects, Ester Boserup's book, "The Conditions of Agricultural Growth," and her subsequent work in which it is argued that population growth is the prime cause of agricultural change is of great importance. The objective of this essay is to review earlier attempts to relate the intensification of agriculture to population growth, to outline Boserup's theory, and to examine the criticisms which have been made of the theory. Boserup maintains that population growth is the cause rather than the result of agricultural change and that the principal change is the intensification of land use. The theory of agricultural development posed by Boserup is more subtle and complex than that of any of her predecessors. She sees population pressure as a major cause of change in land use, agricultural technology, land tenure systems, and settlement form. Boserup argues that population growth is independent of food supply and that population increase is a cause of changes in agriculture. The principal means of increasing agricultural output is intensification. Boserup's work has had a varied response from readers; other economists have been less than enthusiastic. It might seem as if the critics of Boserup's theory have left it in tatters. Her central argument, that intensification reduces labor productivity, remains unproven. There are few who would agree that an increase in the frequency of cropping is the only possible response to population pressure; the extensive margin can be extended, higher yielding crops adopted, and methods that increase yields introduced independently of increases in the frequency of cropping. Emigration or the control of numbers may relieve population pressure. Intensification can also take place without population pressure, under the stimulus of urban growth or the development of trade. It is difficult to accept that population pressure is the only cause or agrarian change or that the increased frequency of cropping is the only response to population pressure, yet the thesis is a fruitful interpretation of agrarian change. Assuming population growth as a change mechanism can lead to important new conclusions regarding the nature of agrarian change in western European history.

The neurobiology of climate change

NASA Astrophysics Data System (ADS)

O'Donnell, Sean

2018-02-01

Directional climate change (global warming) is causing rapid alterations in animals' environments. Because the nervous system is at the forefront of animals' interactions with the environment, the neurobiological implications of climate change are central to understanding how individuals, and ultimately populations, will respond to global warming. Evidence is accumulating for individual level, mechanistic effects of climate change on nervous system development and performance. Climate change can also alter sensory stimuli, changing the effectiveness of sensory and cognitive systems for achieving biological fitness. At the population level, natural selection forces stemming from directional climate change may drive rapid evolutionary change in nervous system structure and function.

The neurobiology of climate change.

PubMed

O'Donnell, Sean

2018-01-06

Directional climate change (global warming) is causing rapid alterations in animals' environments. Because the nervous system is at the forefront of animals' interactions with the environment, the neurobiological implications of climate change are central to understanding how individuals, and ultimately populations, will respond to global warming. Evidence is accumulating for individual level, mechanistic effects of climate change on nervous system development and performance. Climate change can also alter sensory stimuli, changing the effectiveness of sensory and cognitive systems for achieving biological fitness. At the population level, natural selection forces stemming from directional climate change may drive rapid evolutionary change in nervous system structure and function.

Eccentric preformative molt in the spotted Towhee

DOE PAGES

Fettig, Stephen M.; Hathcock, Charles Dean

2016-11-04

Examination of wing-feather molt often provides information essential for aging birds in the hand (Mulvihill 1993, pyle 1997b, 2008). Correctly aging birds is important for understanding the causal relationships between age-class survival rates and population changes (DeSante et al. 2005). For example, correctly aging birds facilitates understanding of climate effects on reproduction better than merely moni- toring population numbers because reproduction varies widely with annual weather patterns (DeSante and O’grady 2000). Age-class information can also provide a clear measure of habitat quality without confounding effects such as population sources and sinks (Van horne 1983) or misleading habitat-quality information based onmore » relative abundance or population size (pulliam 1988). Changes in bird populations often lag changes in the survival rate of an age class, while environmental changes often affect one age class immediately or after a short lag (Temple and Wiens 1989)« less

Applying social marketing in health care: communicating evidence to change consumer behavior.

PubMed

Evans, W Douglas; McCormack, Lauren

2008-01-01

Social marketing uses commercial marketing strategies to change individual and organizational behavior and policies. It has been effective on a population level across a wide range of public health and health care domains. There is limited evidence of the effectiveness of social marketing in changing health care consumer behavior through its impact on patient-provider interaction or provider behavior. Social marketers need to identify translatable strategies (e.g., competition analysis, branding, and tailored messages) that can be applied to health care provider and consumer behavior. Three case studies from social marketing illustrate potential strategies to change provider and consumer behavior. Countermarketing is a rapidly growing social marketing strategy that has been effective in tobacco control and may be effective in countering pharmaceutical marketing using specific message strategies. Informed decision making is a useful strategy when there is medical uncertainty, such as in prostate cancer screening and treatment. Pharmaceutical industry marketing practices offer valuable lessons for developing competing messages to reach providers and consumers. Social marketing is an effective population-based behavior change strategy that can be applied in individual clinical settings and as a complement to reinforce messages communicated on a population level. There is a need for more research on message strategies that work in health care and population-level effectiveness studies.

Physiological basis of climate change impacts on North American inland fishes

USGS Publications Warehouse

Whitney, James E.; Al-Chokhachy, Robert K.; Bunnell, David B.; Caldwell, Colleen A.; Cooke, Steven J.; Eliason, Erika J.; Rogers, Mark W.; Lynch, Abigail J.; Paukert, Craig P.

2016-01-01

Global climate change is altering freshwater ecosystems and affecting fish populations and communities. Underpinning changes in fish distribution and assemblage-level responses to climate change are individual-level physiological constraints. In this review, we synthesize the mechanistic effects of climate change on neuroendocrine, cardiorespiratory, immune, osmoregulatory, and reproductive systems of freshwater and diadromous fishes. Observed climate change effects on physiological systems are varied and numerous, including exceedance of critical thermal tolerances, decreased cardiorespiratory performance, compromised immune function, and altered patterns of individual reproductive investment. However, effects vary widely among and within species because of species, population, and even sex-specific differences in sensitivity and resilience and because of habitat-specific variation in the magnitude of climate-related environmental change. Research on the interactive effects of climate change with other environmental stressors across a broader range of fish diversity is needed to further our understanding of climate change effects on fish physiology.

Integrating population and genetic monitoring to understand changes in the abundance of a threatened seabird

Treesearch

Catalina Vásquez-Carrillo; R. William Henry; Laird Henkel; M. Zachariah Peery

2013-01-01

Population monitoring programs for threatened species are rarely designed to disentangle the effects of movements from changes in birth and death rates on estimated trends in abundance. Here, we illustrate how population and genetic monitoring can be integrated to understand the cause of large changes in the abundance of a threatened species of seabird, the Marbled...

Genecological approaches to predicting the effects of climate change on plant populations

Treesearch

Francis F. Kilkenny

2015-01-01

Climate change threatens native plant populations and plant communities globally. It is critical that land managers have a clear understanding of climate change impacts on plant species and populations so that restoration efforts can be adjusted accordingly. This paper reviews the develop.ment and use of seed transfer guidelines for restoration in the face of global...

Climate change effects on North American inland fish populations and assemblages

USGS Publications Warehouse

Lynch, Abigail J.; Myers, Bonnie; Chu, Cindy; Eby, Lisa A.; Falke, Jeffrey A.; Kovach, Ryan P.; Krabbenhoft, Trevor J.; Kwak, Thomas J.; Lyons, John; Paukert, Craig P.; Whitney, James E.

2016-01-01

Climate is a critical driver of many fish populations, assemblages, and aquatic communities. However, direct observational studies of climate change impacts on North American inland fishes are rare. In this synthesis, we (1) summarize climate trends that may influence North American inland fish populations and assemblages, (2) compile 31 peer-reviewed studies of documented climate change effects on North American inland fish populations and assemblages, and (3) highlight four case studies representing a variety of observed responses ranging from warmwater systems in the southwestern and southeastern United States to coldwater systems along the Pacific Coast and Canadian Shield. We conclude by identifying key data gaps and research needs to inform adaptive, ecosystem-based approaches to managing North American inland fishes and fisheries in a changing climate.

The evolutionary and behavioral modification of consumer responses to environmental change.

PubMed

Abrams, Peter A

2014-02-21

How will evolution or other forms of adaptive change alter the response of a consumer species' population density to environmentally driven changes in population growth parameters? This question is addressed by analyzing some simple consumer-resource models to separate the ecological and evolutionary components of the population's response. Ecological responses are always decreased population size, but evolution of traits that have effects on both resource uptake rate and another fitness-related parameter may magnify, offset, or reverse this population decrease. Evolution can change ecologically driven decreases in population size to increases; this is likely when: (1) resources are initially below the density that maximizes resource growth, and (2) the evolutionary response decreases the consumer's resource uptake rate. Evolutionary magnification of the ecological decreases in population size can occur when the environmental change is higher trait-independent mortality. Such evolution-driven decreases are most likely when uptake-rate traits increase and the resource is initially below its maximum growth density. It is common for the difference between the new eco-evolutionary equilibrium and the new ecological equilibrium to be larger than that between the original and new ecological equilibrium densities. The relative magnitudes of ecological and evolutionary effects often depend sensitively on the magnitude of the environmental change and the nature of resource growth. © 2013 Elsevier Ltd. All rights reserved.

The fingerprints of global climate change on insect populations.

PubMed

Boggs, Carol L

2016-10-01

Synthesizing papers from the last two years, I examined generalizations about the fingerprints of climate change on insects' population dynamics and phenology. Recent work shows that populations can differ in response to changes in climate means and variances. The part of the thermal niche occupied by an insect population, voltinism, plasticity and adaptation to weather perturbations, and interactions with other species can all exacerbate or mitigate responses to climate change. Likewise, land use change or agricultural practices can affect responses to climate change. Nonetheless, our knowledge of effects of climate change is still biased by organism and geographic region, and to some extent by scale of climate parameter. Copyright © 2016 Elsevier Inc. All rights reserved.

Detecting past changes of effective population size

PubMed Central

Nikolic, Natacha; Chevalet, Claude

2014-01-01

Understanding and predicting population abundance is a major challenge confronting scientists. Several genetic models have been developed using microsatellite markers to estimate the present and ancestral effective population sizes. However, to get an overview on the evolution of population requires that past fluctuation of population size be traceable. To address the question, we developed a new model estimating the past changes of effective population size from microsatellite by resolving coalescence theory and using approximate likelihoods in a Monte Carlo Markov Chain approach. The efficiency of the model and its sensitivity to gene flow and to assumptions on the mutational process were checked using simulated data and analysis. The model was found especially useful to provide evidence of transient changes of population size in the past. The times at which some past demographic events cannot be detected because they are too ancient and the risk that gene flow may suggest the false detection of a bottleneck are discussed considering the distribution of coalescence times. The method was applied on real data sets from several Atlantic salmon populations. The method called VarEff (Variation of Effective size) was implemented in the R package VarEff and is made available at https://qgsp.jouy.inra.fr and at http://cran.r-project.org/web/packages/VarEff. PMID:25067949

Limited evolutionary rescue of locally adapted populations facing climate change.

PubMed

Schiffers, Katja; Bourne, Elizabeth C; Lavergne, Sébastien; Thuiller, Wilfried; Travis, Justin M J

2013-01-19

Dispersal is a key determinant of a population's evolutionary potential. It facilitates the propagation of beneficial alleles throughout the distributional range of spatially outspread populations and increases the speed of adaptation. However, when habitat is heterogeneous and individuals are locally adapted, dispersal may, at the same time, reduce fitness through increasing maladaptation. Here, we use a spatially explicit, allelic simulation model to quantify how these equivocal effects of dispersal affect a population's evolutionary response to changing climate. Individuals carry a diploid set of chromosomes, with alleles coding for adaptation to non-climatic environmental conditions and climatic conditions, respectively. Our model results demonstrate that the interplay between gene flow and habitat heterogeneity may decrease effective dispersal and population size to such an extent that substantially reduces the likelihood of evolutionary rescue. Importantly, even when evolutionary rescue saves a population from extinction, its spatial range following climate change may be strongly narrowed, that is, the rescue is only partial. These findings emphasize that neglecting the impact of non-climatic, local adaptation might lead to a considerable overestimation of a population's evolvability under rapid environmental change.

Chapter 3. Effects of climate change and commercial fishing on Atlantic cod Gadus morhua.

PubMed

Mieszkowska, Nova; Genner, Martin J; Hawkins, Stephen J; Sims, David W

2009-01-01

During the course of the last century, populations of Atlantic cod Gadus morhua L. have undergone dramatic declines in abundance across their biogeographic range, leading to debate about the relative roles of climatic warming and overfishing in driving these changes. In this chapter, we describe the geographic distributions of this important predator of North Atlantic ecosystems and document extensive evidence for limitations of spatial movement and local adaptation from population genetic markers and electronic tagging. Taken together, this evidence demonstrates that knowledge of spatial population ecology is critical for evaluating the effects of climate change and commercial harvesting. To explore the possible effects of climate change on cod, we first describe thermal influences on individual physiology, growth, activity and maturation. We then evaluate evidence that temperature has influenced population-level processes including direct effects on recruitment through enhanced growth and activity, and indirect effects through changes to larval food resources. Although thermal regimes clearly define the biogeographic range of the species, and strongly influence many aspects of cod biology, the evidence that population declines across the North Atlantic are strongly linked to fishing activity is now overwhelming. Although there is considerable concern about low spawning stock biomasses, high levels of fishing activity continues in many areas. Even with reduced fishing effort, the potential for recovery from low abundance may be compromised by unfavourable climate and Allee effects. Current stock assessment and management approaches are reviewed, alongside newly advocated methods for monitoring stock status and recovery. However, it remains uncertain whether the rebuilding of cod to historic population sizes and demographic structures will be possible in a warmer North Atlantic.

Applying Organizational Change to Promote Lesbian, Gay, Bisexual, and Transgender Inclusion and Reduce Health Disparities.

PubMed

Eckstrand, Kristen L; Lunn, Mitchell R; Yehia, Baligh R

2017-06-01

Lesbian, gay, bisexual, and transgender (LGBT) populations face numerous barriers when accessing and receiving healthcare, which amplify specific LGBT health disparities. An effective strategic approach is necessary for academic health centers to meet the growing needs of LGBT populations. Although effective organizational change models have been proposed for other minority populations, the authors are not aware of any organizational change models that specifically promote LGBT inclusion and mitigate access barriers to reduce LGBT health disparities. With decades of combined experience, we identify elements and processes necessary to accelerate LGBT organizational change and reduce LGBT health disparities. This framework may assist health organizations in initiating and sustaining meaningful organizational change to improve the health and healthcare of the LGBT communities.

Climate change and pollution speed declines in zebrafish populations.

PubMed

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

2015-03-17

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

Climate change effects on fishes and fisheries: towards a cause-and-effect understanding.

PubMed

Pörtner, H O; Peck, M A

2010-11-01

Ongoing climate change is predicted to affect individual organisms during all life stages, thereby affecting populations of a species, communities and the functioning of ecosystems. These effects of climate change can be direct, through changing water temperatures and associated phenologies, the lengths and frequency of hypoxia events, through ongoing ocean acidification trends or through shifts in hydrodynamics and in sea level. In some cases, climate interactions with a species will also, or mostly, be indirect and mediated through direct effects on key prey species which change the composition and dynamic coupling of food webs. Thus, the implications of climate change for marine fish populations can be seen to result from phenomena at four interlinked levels of biological organization: (1) organismal-level physiological changes will occur in response to changing environmental variables such as temperature, dissolved oxygen and ocean carbon dioxide levels. An integrated view of relevant effects, adaptation processes and tolerance limits is provided by the concept of oxygen and capacity-limited thermal tolerance (OCLT). (2) Individual-level behavioural changes may occur such as the avoidance of unfavourable conditions and, if possible, movement into suitable areas. (3) Population-level changes may be observed via changes in the balance between rates of mortality, growth and reproduction. This includes changes in the retention or dispersion of early life stages by ocean currents, which lead to the establishment of new populations in new areas or abandonment of traditional habitats. (4) Ecosystem-level changes in productivity and food web interactions will result from differing physiological responses by organisms at different levels of the food web. The shifts in biogeography and warming-induced biodiversity will affect species productivity and may, thus, explain changes in fisheries economies. This paper tries to establish links between various levels of biological organization by means of addressing the effective physiological principles at the cellular, tissue and whole organism levels. © 2010 The Authors. Journal of Fish Biology © 2010 The Fisheries Society of the British Isles.

Effects of temporal variation in temperature and density dependence on insect population dynamics

USDA-ARS?s Scientific Manuscript database

Understanding effects of environmental variation on insect populations is important in light of predictions about increasing future climatic variability. In order to understand the effects of changing environmental variation on population dynamics and life history evolution in insects one would need...

Dynamics of change in local physician supply: an ecological perspective.

PubMed

Jiang, H Joanna; Begun, James W

2002-05-01

The purpose of this study is to employ an ecological framework to identify factors that have an impact on change in local physician supply within the USA. A particular specialty type of patient care physicians in a local market is defined as a physician population. Four physician populations are identified: generalists, medical specialists, surgical specialists, and hospital-based specialists. Based on population ecology theory, the proposed framework explains the growth of a particular physician population by four mechanisms: the intrinsic properties of this physician population; the local market's carrying capacity, which is determined by three environmental dimensions (munificence, concentration, diversity); competition within the same physician population; and interdependence between different physician populations. Data at the level of Metropolitan Statistical Areas (MSAs) were compiled from the US Area Resources File, the American Hospital Association Annual Surveys of Hospitals, the American Medical Association Census of Medical Groups, the InterStudy National HMO Census, and the US County Business Patterns. Changes in the number and percentage of physicians in a particular specialty population from 1985 to 1994 were regressed, respectively, on 1985-94 changes in the explanatory variables as well as their levels in 1985. The results indicate that the population ecology framework is useful in explaining dynamics of change in the local physician workforce. Variables measuring the three environmental dimensions were found to have significant, and in some cases, differential effects on change in the size of different specialty populations. For example, both hospital consolidation and managed care penetration showed significant positive eflects on growth of the generalist population but suppressing effects on growth of the specialist population. The percentage of physicians in a particular specialty population in 1985 was negatively related to change in the size of that specialty population between 1985 and 1994, suggesting the existence of competition. Overall, the findings of this study facilitate a better understanding of the complexity of physician workforce supply.

Ecotoxicology of mercury in fish and wildlife: Recent advances

USGS Publications Warehouse

Scheuhammer, Anton M.; Basu, Niladri; Evers, David C.; Heinz, Gary H.; Sandheinrich, Mark B.; Bank, Michael S.; edited by Bank, Michael S.; Bank, Michael S.

2012-01-01

A number of recent studies have documented subtle, yet potentially important effects of mercury on behavior, neurochemistry, and endocrine function in fish and wildlife at currently realistic levels of environmental exposure. Current levels of environmental methylmercury exposure are sufficient to cause significant biological impairment, both in individuals and in whole populations, in some ecosystems. Future toxicological studies on fish and wildlife will focus on linking biomarkers of methylmercury exposure and associated oxidative stress to effects on reproduction and population change; determining the genetic basis for mercury-related neurotoxic and other biological changes; determining the genetic basis for species differences in sensitivity to methylmercury; and linking toxic effects of methylmercury in individual animals to population-level changes.

Effect of extreme sea surface temperature events on the demography of an age-structured albatross population.

PubMed

Pardo, Deborah; Jenouvrier, Stéphanie; Weimerskirch, Henri; Barbraud, Christophe

2017-06-19

Climate changes include concurrent changes in environmental mean, variance and extremes, and it is challenging to understand their respective impact on wild populations, especially when contrasted age-dependent responses to climate occur. We assessed how changes in mean and standard deviation of sea surface temperature (SST), frequency and magnitude of warm SST extreme climatic events (ECE) influenced the stochastic population growth rate log( λ s ) and age structure of a black-browed albatross population. For changes in SST around historical levels observed since 1982, changes in standard deviation had a larger (threefold) and negative impact on log( λ s ) compared to changes in mean. By contrast, the mean had a positive impact on log( λ s ). The historical SST mean was lower than the optimal SST value for which log( λ s ) was maximized. Thus, a larger environmental mean increased the occurrence of SST close to this optimum that buffered the negative effect of ECE. This 'climate safety margin' (i.e. difference between optimal and historical climatic conditions) and the specific shape of the population growth rate response to climate for a species determine how ECE affect the population. For a wider range in SST, both the mean and standard deviation had negative impact on log( λ s ), with changes in the mean having a greater effect than the standard deviation. Furthermore, around SST historical levels increases in either mean or standard deviation of the SST distribution led to a younger population, with potentially important conservation implications for black-browed albatrosses.This article is part of the themed issue 'Behavioural, ecological and evolutionary responses to extreme climatic events'. © 2017 The Author(s).

The role of population density on the impact of urbaniza-tion on GHG emissions in China

NASA Astrophysics Data System (ADS)

Liu, Yonghong; Gao, Chaochao; Lu, Yingying

2017-04-01

Urbanization directly drives rural to urban population migration and indirectly causes west to east migration in China, two phenomena that may significantly impact China's greenhouse gas emissions given its huge population and vast difference between the western rural and eastern urban areas. These two phenomena were analyzed by using emissions as a per capita term, and extending the impact from the traditional urbanization rate effect to include population density effect. The results show that population density has actually been the dominant demographic player in changing per capita emissions for the past two decades in China, and its elasticity changed from positive in economically less-developed provinces to negative for the developed provinces. This study provides a new perspective in the study of the relationship between urbanization and greenhouse gas emissions, and the results indicate that population density change should be taken into account to accurately assess the impact of urbanization.

Effects of economic crises on population health outcomes in Latin America, 1981-2010: an ecological study.

PubMed

Williams, Callum; Gilbert, Barnabas James; Zeltner, Thomas; Watkins, Johnathan; Atun, Rifat; Maruthappu, Mahiben

2016-01-06

The relative health effects of changes in unemployment, inflation and gross domestic product (GDP) per capita on population health have not been assessed. We aimed to determine the effect of changes in these economic measures on mortality metrics across Latin America. Ecological study. Latin America (21 countries), 1981-2010. Uses multivariate regression analysis to assess the effects of changes in unemployment, inflation and GDP per capita on 5 mortality indicators across 21 countries in Latin America, 1981-2010. Country-specific differences in healthcare infrastructure, population structure and population size were controlled for. Between 1981 and 2010, a 1% rise in unemployment was associated with statistically significant deteriorations (p<0.05) in 5 population health outcomes, with largest deteriorations in 1-5 years of age and male adult mortality rates (1.14 and 0.53 rises per 1000 deaths respectively). A 1% rise in inflation rate was associated with significant deteriorations (p<0.05) in 4 population health outcomes, with the largest deterioration in male adult mortality rate (0.0033 rise per 1000 deaths). Lag analysis showed that 5 years after rises in unemployment and inflation, significant deteriorations (p<0.05) occurred in 3 and 5 mortality metrics, respectively. A 1% rise in GDP per capita was associated with no significant deteriorations in population health outcomes either in the short or long term. β coefficient comparisons indicated that the effect of unemployment increases was substantially greater than that of changes in GDP per capita or inflation. Rises in unemployment and inflation are associated with long-lasting deteriorations in several population health outcomes. Unemployment exerted much larger effects on health than inflation. In contrast, changes in GDP per capita had almost no association with the explored health outcomes. Contrary to neoclassical development economics, policymakers should prioritise amelioration of unemployment if population health outcomes are to be optimised. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Predicting the variation in Echinogammarus marinus at its southernmost limits under global warming scenarios: can the sex-ratio make a difference?

PubMed

Guerra, Alexandra; Leite, Nuno; Marques, João Carlos; Ford, Alex T; Martins, Irene

2014-01-01

Understanding the environmental parameters that constrain the distribution of a species at its latitudinal extremes is critical for predicting how ecosystems react to climate change. Our first aim was to predict the variation in the amphipod populations of Echinogammarus marinus from the southernmost limit of its distribution under global warming scenarios. Our second aim was to test whether sex-ratio fluctuations - a mechanism frequently displayed by amphipods - respond to the variations in populations under altered climate conditions. To achieve these aims, scenarios were run with a validated model of E. marinus populations. Simulations were divided into: phase I - simulation of the effect of climate change on amphipod populations, and phase II - simulation of the effect of climate change on populations with male and female proportions. In both phases, temperature (T), salinity (S) and temperature and salinity (T-S) were tested. Results showed that E. marinus populations are highly sensitive to increases in temperature (>2 °C), which has adverse effects on amphipod recruitment and growth. Results from the climate change scenarios coupled with the sex-ratio fluctuations depended largely on the degree of female bias within population. Temperature increase of 2 °C had less impact on female-biased populations, particularly when conjugated with increases in salinity. Male-biased populations were highly sensitive to any variation in temperature and/or salinity; these populations exhibited a long-term decline in density. Simulations in which temperature increased more than 4 °C led to a continuous decline in the E. marinus population. According to this work, E. marinus populations at their southernmost limit are vulnerable to global warming. We anticipate that in Europe, temperature increases of 2 °C will incite a withdrawal of the population of 5°N from the amphipod species located at southernmost geographical borders. This effect is discussed in relation to the distribution of E. marinus along the Atlantic coast. © 2013 Elsevier B.V. All rights reserved.

Implications Climate Change for Contaminant Management: Effects of Temperature on Individual and population toxicity in Daphnia Magna

EPA Science Inventory

A main goal of ecotoxicology and risk assessment is to assess the impact on aquatic populations. However the most widely used bioassays measure the response of individuals to infer population effects. Bridging the gap between established individual-based methodology and the popul...

The effect of sexual selection on adaptation and extinction under increasing temperatures.

PubMed

Parrett, Jonathan M; Knell, Robert J

2018-04-25

Strong sexual selection has been reported to both enhance and hinder the adaptive capacity and persistence of populations when exposed to novel environments. Consequently, how sexual selection influences population adaption and persistence under stress remains widely debated. Here, we present two empirical investigations of the fitness consequences of sexual selection on populations of the Indian meal moth, Plodia interpunctella, exposed to stable or gradually increasing temperatures. When faced with increasing temperatures, strong sexual selection was associated with both increased fecundity and offspring survival compared with populations experiencing weak sexual selection, suggesting sexual selection acts to drive adaptive evolution by favouring beneficial alleles. Strong sexual selection did not, however, delay extinction when the temperature became excessively high. By manipulating individuals' mating opportunities during fitness assays, we were able to assess the effect of multiple mating independently from the effect of population-level sexual selection, and found that polyandry has a positive effect on both fecundity and offspring survival under increasing temperatures in those populations evolving with weak sexual selection. Within stable temperatures, there were some benefits from strong sexual selection but these were not consistent across the entire experiment, possibly reflecting changing costs and benefits of sexual selection under stabilizing and directional selection. These results indicate that sexual selection can provide a buffer against climate change and increase adaptation rates within a continuously changing environment. These positive effects of sexual selection may, however, be too small to protect populations and delay extinction when environmental changes are relatively rapid. © 2018 The Author(s).

The effect of education on climate change risks

NASA Astrophysics Data System (ADS)

O'Neill, B. C.; KC, S.; Jiang, L.; Fuchs, R.; Pachauri, S.; Ren, X.; Zhang, T.; Laidlaw, E.

2017-12-01

Changes in the demographic and socio-economic compositions of populations are relevant to the climate change issue because these characteristics can be important determinants both of the capacity to adapt to climate change impacts as well as of energy use and greenhouse gas emissions, and therefore climate change. However, the incorporation of major trends such as aging, urbanization, and changes in household size into projections of future energy use and emissions is rare. Here we build on our previous work in this area by exploring the implications of future changes in educational attainment for the climate issue. Changes in the educational composition of the population may reduce the vulnerability of the population to climate change impacts, reducing risks. However they may also have effects on energy use and land use, and the resulting greenhouse gas emissions that drive climate change and increase risks. The direction of the effect of education on emissions is itself ambiguous. On the one hand, improvements in education can be expected to lead to faster fertility decline and slower population growth which, all else equal, would be expected to reduce emissions. On the other hand, education can also be expected to lead to faster economic growth, which would tend to increase emissions, and also to changes in consumption patterns. We employ iPETS, an integrated assessment model that includes a multi-region model of the world economy, driven with a new set of country-specific projections of future educational composition, to test the net effect of education on energy use and emissions on four world regions (China, India, Latin America, and Rest of Asia + Middle East) and therefore on climate. We also calculate the Human Development Index (HDI) for each region resulting from these scenarios, as an indicator of vulnerability to climate impacts. We find that the net effect of improved education is to increase emissions in the medium term driven primarily by increased labor productivity, but decrease emissions in the long term primarily as a result of slower population growth. At the same time, improved education positively affects all aspects of the HDI at all time horizons. Important caveats include the uncertainty in the effect of education on economic growth.

Interacting stressors and the potential for adaptation in a changing world: responses of populations and individuals

PubMed Central

French, Susannah S.; Brodie, Edmund D.

2017-01-01

To accurately predict the impact of environmental change, it is necessary to assay effects of key interacting stressors on vulnerable organisms, and the potential resiliency of their populations. Yet, for the most part, these critical data are missing. We examined the effects of two common abiotic stressors predicted to interact with climate change, salinity and temperature, on the embryonic survival and development of a model freshwater vertebrate, the rough-skinned newt (Taricha granulosa) from different populations. We found that salinity and temperature significantly interacted to affect newt embryonic survival and development, with the negative effects of salinity most pronounced at temperature extremes. We also found significant variation among, and especially within, populations, with different females varying in the performance of their eggs at different salinity–temperature combinations, possibly providing the raw material for future natural selection. Our results highlight the complex nature of predicting responses to climate change in space and time, and provide critical data towards that aim. PMID:28680662

Demographic change and carbon dioxide emissions.

PubMed

O'Neill, Brian C; Liddle, Brant; Jiang, Leiwen; Smith, Kirk R; Pachauri, Shonali; Dalton, Michael; Fuchs, Regina

2012-07-14

Relations between demographic change and emissions of the major greenhouse gas carbon dioxide (CO(2)) have been studied from different perspectives, but most projections of future emissions only partly take demographic influences into account. We review two types of evidence for how CO(2) emissions from the use of fossil fuels are affected by demographic factors such as population growth or decline, ageing, urbanisation, and changes in household size. First, empirical analyses of historical trends tend to show that CO(2) emissions from energy use respond almost proportionately to changes in population size and that ageing and urbanisation have less than proportional but statistically significant effects. Second, scenario analyses show that alternative population growth paths could have substantial effects on global emissions of CO(2) several decades from now, and that ageing and urbanisation can have important effects in particular world regions. These results imply that policies that slow population growth would probably also have climate-related benefits. Copyright © 2012 Elsevier Ltd. All rights reserved.

Climate Change and Human Disturbance Can Lead to Local Extinction of Alpine Rock Ptarmigan: New Insight from the Western Italian Alps

PubMed Central

Imperio, Simona; Bionda, Radames; Viterbi, Ramona; Provenzale, Antonello

2013-01-01

Alpine grouses are particularly vulnerable to climate change due to their adaptation to extreme conditions and to their relict distributions in the Alps where global warming has been particularly marked in the last half century. Grouses are also currently threatened by habitat modification and human disturbance, and an assessment of the impact of multiple stressors is needed to predict the fate of Alpine populations of these birds in the next decades. We estimated the effect of climate change and human disturbance on a rock ptarmigan population living in the western Italian Alps by combining an empirical population modelling approach and stochastic simulations of the population dynamics under the a1B climate scenario and two different disturbance scenarios, represented by the development of a ski resort, through 2050.The early appearance of snow-free ground in the previous spring had a favorable effect on the rock ptarmigan population, probably through a higher reproductive success. On the contrary, delayed snowfall in autumn had a negative effect possibly due to a mismatch in time to molt to white winter plumage which increases predation risk. The regional climate model PROTHEUS does not foresee any significant change in snowmelt date in the study area, while the start date of continuous snow cover is expected to be significantly delayed. The net effect in the stochastic projections is a more or less pronounced (depending on the model used) decline in the studied population. The addition of extra-mortality due to collision with ski-lift wires led the population to fatal consequences in most projections. Should these results be confirmed by larger studies the conservation of Alpine populations would deserve more attention. To counterbalance the effects of climate change, the reduction of all causes of death should be pursued, through a strict preservation of the habitats in the present area of occurrence. PMID:24260581

Climate change and human disturbance can lead to local extinction of Alpine rock ptarmigan: new insight from the western Italian Alps.

PubMed

Imperio, Simona; Bionda, Radames; Viterbi, Ramona; Provenzale, Antonello

2013-01-01

Alpine grouses are particularly vulnerable to climate change due to their adaptation to extreme conditions and to their relict distributions in the Alps where global warming has been particularly marked in the last half century. Grouses are also currently threatened by habitat modification and human disturbance, and an assessment of the impact of multiple stressors is needed to predict the fate of Alpine populations of these birds in the next decades. We estimated the effect of climate change and human disturbance on a rock ptarmigan population living in the western Italian Alps by combining an empirical population modelling approach and stochastic simulations of the population dynamics under the a1B climate scenario and two different disturbance scenarios, represented by the development of a ski resort, through 2050.The early appearance of snow-free ground in the previous spring had a favorable effect on the rock ptarmigan population, probably through a higher reproductive success. On the contrary, delayed snowfall in autumn had a negative effect possibly due to a mismatch in time to molt to white winter plumage which increases predation risk. The regional climate model PROTHEUS does not foresee any significant change in snowmelt date in the study area, while the start date of continuous snow cover is expected to be significantly delayed. The net effect in the stochastic projections is a more or less pronounced (depending on the model used) decline in the studied population. The addition of extra-mortality due to collision with ski-lift wires led the population to fatal consequences in most projections. Should these results be confirmed by larger studies the conservation of Alpine populations would deserve more attention. To counterbalance the effects of climate change, the reduction of all causes of death should be pursued, through a strict preservation of the habitats in the present area of occurrence.

Responses to alternative rainfall regimes and antipoaching in a migratory system.

PubMed

Holdo, Ricardo M; Galvin, Kathleen A; Knapp, Eli; Polasky, Stephen; Hilborn, Ray; Holt, Robert D

2010-03-01

Migratory ungulates may be particularly vulnerable to the challenges imposed by growing human populations and climate change. These species depend on vast areas to sustain their migratory behavior, and in many cases come into frequent contact with human populations outside protected areas. They may also act as spatial coupling agents allowing feedbacks between ecological systems and local economies, particularly in the agropastoral subsistence economies found in the African savanna biome. We used HUMENTS, a spatially realistic socioecological model of the Greater Serengeti Ecosystem in East Africa, to explore the potential impacts of changing climate and poaching on the migratory wildebeest (Connochaetes taurinus) population, the fire regime, and habitat structure in the ecosystem, as well as changes in the size and economic activities of the human population outside the protected area. Unlike earlier models, the HUMENTS model predicted only moderate declines in the wildebeest population associated with an increasing human population over the next century, with a gradual expansion of agriculture, more poaching, and increases in fire frequency and reduced tree density. Changes in rainfall were predicted to have strong asymmetric effects on the size and economic activity of the human population and on livestock, and more moderate effects on wildlife and other ecological indicators. Conversely, antipoaching had a stronger effect on the ecological portion of the system because of its effect on wildebeest (and therefore on fire and habitat structure), and a weaker effect on the socioeconomic component, except in areas directly adjacent to the protected-area boundary, which were affected by crop-raiding and the availability of wildlife as a source of income. The results highlight the strong direct and indirect effects of rainfall on the various components of socioecological systems in semiarid environments, and the key role of mobile wildlife populations as agents of spatial coupling between the human-dominated and natural portions of ecosystems. They also underscore the fundamental importance of considering the spatial configuration of hunting refuges across the landscape in relation to human populations.

Do food availability, parasitism, and stress have synergistic effects on red colobus populations living in forest fragments?

PubMed

Chapman, Colin A; Wasserman, Michael D; Gillespie, Thomas R; Speirs, Michaela L; Lawes, Michael J; Saj, Tania L; Ziegler, Toni E

2006-12-01

Identifying factors that influence animal density is a fundamental goal in ecology that has taken on new importance with the need to develop informed management plans. This is particularly the case for primates as the tropical forest that supports many species is being rapidly converted. We use a system of forest fragments adjacent to Kibale National Park, Uganda, to examine if food availability and parasite infections have synergistic affects on red colobus (Piliocolobus tephrosceles) abundance. Given that the size of primate populations can often respond slowly to environmental changes, we also examined how these factors influenced cortisol levels. To meet these objectives, we monitored gastrointestinal parasites, evaluated fecal cortisol levels, and determined changes in food availability by conducting complete tree inventories in eight fragments in 2000 and 2003. Red colobus populations declined by an average of 21% among the fragments; however, population change ranged from a 25% increase to a 57% decline. The cumulative basal area of food trees declined by an average of 29.5%; however, forest change was highly variable (a 2% gain to a 71% decline). We found that nematode prevalence averaged 58% among fragments (range 29-83%). The change in colobus population size was correlated both with food availability and a number of indices of parasite infections. A path analysis suggests that change in food availability has a strong direct effect on population size, but it also has an indirect effect via parasite infections. 2006 Wiley-Liss, Inc.

Climate change overruns resilience conferred by temperature-dependent sex determination in sea turtles and threatens their survival.

PubMed

Santidrián Tomillo, Pilar; Genovart, Meritxell; Paladino, Frank V; Spotila, James R; Oro, Daniel

2015-08-01

Temperature-dependent sex determination (TSD) is the predominant form of environmental sex determination (ESD) in reptiles, but the adaptive significance of TSD in this group remains unclear. Additionally, the viability of species with TSD may be compromised as climate gets warmer. We simulated population responses in a turtle with TSD to increasing nest temperatures and compared the results to those of a virtual population with genotypic sex determination (GSD) and fixed sex ratios. Then, we assessed the effectiveness of TSD as a mechanism to maintain populations under climate change scenarios. TSD populations were more resilient to increased nest temperatures and mitigated the negative effects of high temperatures by increasing production of female offspring and therefore, future fecundity. That buffered the negative effect of temperature on the population growth. TSD provides an evolutionary advantage to sea turtles. However, this mechanism was only effective over a range of temperatures and will become inefficient as temperatures rise to levels projected by current climate change models. Projected global warming threatens survival of sea turtles, and the IPCC high gas concentration scenario may result in extirpation of the studied population in 50 years. © 2015 John Wiley & Sons Ltd.

MODELING THE DYNAMICS OF WILDLIFE HABITAT AND POPULATIONS AT THE LANDSCAPE SCALE

EPA Science Inventory

A forest dynamics model (FORCLIM) was linked to a spatial wildlife population model (PATCH) to assess the effects of habitat change in a landscape on selected wildlife species. The habitat changes included forest responses to harvesting, development, and climate change on a west...

Land-use change has no detectable effect on reproduction of a disturbance-adapted, hawkmoth-pollinated plant species.

PubMed

Skogen, Krissa A; Jogesh, Tania; Hilpman, Evan T; Todd, Sadie L; Rhodes, Matthew K; Still, Shannon M; Fant, Jeremie B

2016-11-01

Land-use change is cited as a primary driver of global biodiversity loss, with myriad consequences for species, populations, and ecosystems. However, few studies have examined its impact on species interactions, particularly pollination. Furthermore, when the effects of land-use change on pollination have been studied, the focus has largely been on species pollinated by diurnal pollinators, namely, bees and butterflies. Here, we focus on Oenothera harringtonii, a night-flowering, disturbance-adapted species that has experienced a range-wide gradient of land-use change. We tested the hypothesis that the negative impacts of land-use change are mitigated by long-distance pollination. Our study included both temporal (4 yr) and spatial (19 populations range-wide, and 1, 2, and 5 km from the population center) data, providing a comprehensive understanding of the role of land-use change on pollination biology and reproduction. We first confirmed that O. harringtonii is self-incompatible and reliant on pollinators for reproduction. We then showed that hawkmoths (primarily Hyles lineata) are highly reliable and effective pollinators in both space and time. Unlike other studies, we did not detect an effect of population size, increased isolation, or a reduction in suitable habitat in areas with evidence of land-use change on pollination (visitation, pollen removal and deposition). Furthermore, the proportion of suitable habitat and other fragmentation metrics examined were not associated with population size or density in this plant species. We conclude that nocturnal pollination of Oenothera harringtonii via hawkmoths is robust to the negative impacts of land-use change. © 2016 Skogen et al. Published by the Botanical Society of America. This work is licensed under a Creative Commons Attribution License (CC-BY).

Genetic signals of past demographic changes and the history of oak populations in California

NASA Astrophysics Data System (ADS)

Dodd, R. S.

2009-04-01

A retrospective view of species' demographic changes can inform on population stability through times of climatic change and the origins and spatial structure of genetic diversity in contemporary populations. The former provides the means to predict responses to future climatic change, while the latter allows us to infer the ability of populations to buffer the effects of reductions in population size and fragmentation. The approximately 1.8 my of the Pleistocene is believed to have had a significant impact on diversity through high rates of extinction during early glacial cycles and population expansions and contractions during the later cycles. In the Mediterranean basin, early emphasis on taxa with wide latitudinal ranges led to models of refugial sites and subsequent recolonization routes that could explain geographic patterns in genetic diversity, with a trend towards reduced genetic diversity in the north. More recently, the study of strictly Mediterranean taxa has revealed relictual sites that have persisted over very long periods of time, commonly relatively poor in diversity, but populations well differentiated from one site to another. In California, relatively little is known of the population dynamics of plant taxa during the Pleistocene glacial cycles, or to what extent differentiation today is a result of pre-Pleistocene events. For several animal taxa, differentiation between Coastal and Sierran taxa are believed to date to the Pliocene. Major demographic changes resulting in population isolation, bottlenecks, founder events and population expansions leave a genetic signal that can be detected through appropriate genetic markers and analyses. Such signals help to infer whether past climate fluctuations have had important effects on population demographics. Here, I will focus on key oak species of the California mediterranean climate zone. I will explore the likely effects of the last glacial maximum on oak populations using palaeoclimate and niche modeling together with analyses of population genetic structure. One of the major questions that will be addressed is whether populations have persisted over long periods of time and if the contemporary population structure has derived from events earlier than the Pleistocene. Population genetic structure will then be used to propose strategies that will optimize conservation of genetic resources.

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

USGS Publications Warehouse

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

2010-01-01

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

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

PubMed

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

2010-08-01

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

Modeling responses of large-river fish populations to global climate change through downscaling and incorporation of predictive uncertainty

USGS Publications Warehouse

Wildhaber, Mark L.; Wikle, Christopher K.; Anderson, Christopher J.; Franz, Kristie J.; Moran, Edward H.; Dey, Rima; Mader, Helmut; Kraml, Julia

2012-01-01

Climate change operates over a broad range of spatial and temporal scales. Understanding its effects on ecosystems requires multi-scale models. For understanding effects on fish populations of riverine ecosystems, climate predicted by coarse-resolution Global Climate Models must be downscaled to Regional Climate Models to watersheds to river hydrology to population response. An additional challenge is quantifying sources of uncertainty given the highly nonlinear nature of interactions between climate variables and community level processes. We present a modeling approach for understanding and accomodating uncertainty by applying multi-scale climate models and a hierarchical Bayesian modeling framework to Midwest fish population dynamics and by linking models for system components together by formal rules of probability. The proposed hierarchical modeling approach will account for sources of uncertainty in forecasts of community or population response. The goal is to evaluate the potential distributional changes in an ecological system, given distributional changes implied by a series of linked climate and system models under various emissions/use scenarios. This understanding will aid evaluation of management options for coping with global climate change. In our initial analyses, we found that predicted pallid sturgeon population responses were dependent on the climate scenario considered.

Communication and marketing as climate change-intervention assets a public health perspective.

PubMed

Maibach, Edward W; Roser-Renouf, Connie; Leiserowitz, Anthony

2008-11-01

The understanding that global climate change represents a profound threat to the health and well-being of human and nonhuman species worldwide is growing. This article examines the potential of communication and marketing interventions to influence population behavior in ways consistent with climate change prevention and adaptation objectives. Specifically, using a framework based on an ecologic model of public health, the paper examines: (1) the potential of communication and marketing interventions to influence population behaviors of concern, including support for appropriate public policies; (2) potential target audiences for such programs; and (3) the attributes of effective climate change messages. Communication and marketing interventions appear to have considerable potential to promote important population behavior change objectives, but there is an urgent need for additional translational research to effectively harvest this potential to combat climate change.

An evaluation of sex-age-kill (SAK) model performance

USGS Publications Warehouse

Millspaugh, Joshua J.; Skalski, John R.; Townsend, Richard L.; Diefenbach, Duane R.; Boyce, Mark S.; Hansen, Lonnie P.; Kammermeyer, Kent

2009-01-01

The sex-age-kill (SAK) model is widely used to estimate abundance of harvested large mammals, including white-tailed deer (Odocoileus virginianus). Despite a long history of use, few formal evaluations of SAK performance exist. We investigated how violations of the stable age distribution and stationary population assumption, changes to male or female harvest, stochastic effects (i.e., random fluctuations in recruitment and survival), and sampling efforts influenced SAK estimation. When the simulated population had a stable age distribution and λ > 1, the SAK model underestimated abundance. Conversely, when λ < 1, the SAK overestimated abundance. When changes to male harvest were introduced, SAK estimates were opposite the true population trend. In contrast, SAK estimates were robust to changes in female harvest rates. Stochastic effects caused SAK estimates to fluctuate about their equilibrium abundance, but the effect dampened as the size of the surveyed population increased. When we considered both stochastic effects and sampling error at a deer management unit scale the resultant abundance estimates were within ±121.9% of the true population level 95% of the time. These combined results demonstrate extreme sensitivity to model violations and scale of analysis. Without changes to model formulation, the SAK model will be biased when λ ≠ 1. Furthermore, any factor that alters the male harvest rate, such as changes to regulations or changes in hunter attitudes, will bias population estimates. Sex-age-kill estimates may be precise at large spatial scales, such as the state level, but less so at the individual management unit level. Alternative models, such as statistical age-at-harvest models, which require similar data types, might allow for more robust, broad-scale demographic assessments.

Influence of body condition on the population dynamics of Atlantic salmon with consideration of the potential impact of sea lice.

PubMed

Susdorf, R; Salama, N K G; Lusseau, D

2017-11-21

Atlantic salmon Salmo salar is an iconic species of high conservation and economic importance. At sea, individuals typically are subject to sea lice infestation, which can have detrimental effects on their host. Over recent decades, the body condition and marine survival in NE Atlantic stocks have generally decreased, reflected in fewer adults returning to rivers, which is partly attributable to sea lice. We developed a deterministic stage-structured population model to assess condition-mediated population dynamics resulting in changing fecundity, age at sexual maturation and marine survival rate. The model is parameterized using data from the North Esk system, north-east Scotland. Both constant and density-dependent juvenile survival rates are considered. We show that even small sea lice-mediated changes in mean body condition of MSW can cause substantial population declines, whereas 1SW condition is less influential. Density dependence alleviates the condition-mediated population effect. The resilience of the population to demographic perturbations declines as adult condition is reduced. Indirect demographic changes in salmonid life-history traits (e.g., body condition) are often considered unimportant for population trajectory. The model shows that Atlantic salmon population dynamics can be highly responsive to sea lice-mediated effects on adult body condition, thus highlighting the importance of non-lethal parasitic long-term effects. © 2017 The Authors Journal of Fish Diseases Published by John Wiley & Sons Ltd.

Fire management, managed relocation, and land conservation options for long-lived obligate seeding plants under global changes in climate, urbanization, and fire regime.

PubMed

Bonebrake, Timothy C; Syphard, Alexandra D; Franklin, Janet; Anderson, Kurt E; Akçakaya, H Resit; Mizerek, Toni; Winchell, Clark; Regan, Helen M

2014-08-01

Most species face multiple anthropogenic disruptions. Few studies have quantified the cumulative influence of multiple threats on species of conservation concern, and far fewer have quantified the potential relative value of multiple conservation interventions in light of these threats. We linked spatial distribution and population viability models to explore conservation interventions under projected climate change, urbanization, and changes in fire regime on a long-lived obligate seeding plant species sensitive to high fire frequencies, a dominant plant functional type in many fire-prone ecosystems, including the biodiversity hotspots of Mediterranean-type ecosystems. First, we investigated the relative risk of population decline for plant populations in landscapes with and without land protection under an existing habitat conservation plan. Second, we modeled the effectiveness of relocating both seedlings and seeds from a large patch with predicted declines in habitat area to 2 unoccupied recipient patches with increasing habitat area under 2 projected climate change scenarios. Finally, we modeled 8 fire return intervals (FRIs) approximating the outcomes of different management strategies that effectively control fire frequency. Invariably, long-lived obligate seeding populations remained viable only when FRIs were maintained at or above a minimum level. Land conservation and seedling relocation efforts lessened the impact of climate change and land-use change on obligate seeding populations to differing degrees depending on the climate change scenario, but neither of these efforts was as generally effective as frequent translocation of seeds. While none of the modeled strategies fully compensated for the effects of land-use and climate change, an integrative approach managing multiple threats may diminish population declines for species in complex landscapes. Conservation plans designed to mitigate the impacts of a single threat are likely to fail if additional threats are ignored. © 2014 Society for Conservation Biology.

Independent Demographic Responses to Climate Change among Temperate and Tropical Milksnakes (Colubridae: Genus Lampropeltis)

PubMed Central

Ruane, Sara; Torres-Carvajal, Omar; Burbrink, Frank T.

2015-01-01

The effects of Late Quaternary climate change have been examined for many temperate New World taxa, but the impact of Pleistocene glacial cycles on Neotropical taxa is less well understood, specifically with respect to changes in population demography. Here, we examine historical demographic trends for six species of milksnake with representatives in both the temperate and tropical Americas to determine if species share responses to climate change as a taxon or by area (i.e., temperate versus tropical environments). Using a multilocus dataset, we test for the demographic signature of population expansion and decline using non-genealogical summary statistics, as well as coalescent-based methods. In addition, we determine whether range sizes are correlated with effective population sizes for milksnakes. Results indicate that there are no identifiable trends with respect to demographic response based on location, and that species responded to changing climates independently, with tropical taxa showing greater instability. There is also no correlation between range size and effective population size, with the largest population size belonging to the species with the smallest geographic distribution. Our study highlights the importance of not generalizing the demographic histories of taxa by region and further illustrates that the New World tropics may not have been a stable refuge during the Pleistocene. PMID:26083467

Independent Demographic Responses to Climate Change among Temperate and Tropical Milksnakes (Colubridae: Genus Lampropeltis).

PubMed

Ruane, Sara; Torres-Carvajal, Omar; Burbrink, Frank T

2015-01-01

The effects of Late Quaternary climate change have been examined for many temperate New World taxa, but the impact of Pleistocene glacial cycles on Neotropical taxa is less well understood, specifically with respect to changes in population demography. Here, we examine historical demographic trends for six species of milksnake with representatives in both the temperate and tropical Americas to determine if species share responses to climate change as a taxon or by area (i.e., temperate versus tropical environments). Using a multilocus dataset, we test for the demographic signature of population expansion and decline using non-genealogical summary statistics, as well as coalescent-based methods. In addition, we determine whether range sizes are correlated with effective population sizes for milksnakes. Results indicate that there are no identifiable trends with respect to demographic response based on location, and that species responded to changing climates independently, with tropical taxa showing greater instability. There is also no correlation between range size and effective population size, with the largest population size belonging to the species with the smallest geographic distribution. Our study highlights the importance of not generalizing the demographic histories of taxa by region and further illustrates that the New World tropics may not have been a stable refuge during the Pleistocene.

Estimation of population trajectories from count data

USGS Publications Warehouse

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

1997-01-01

Monitoring of changes in animal population size is rarely possible through complete censuses; frequently, the only feasible means of monitoring changes in population size is to use counts of animals obtained by skilled observers as indices to abundance. Analysis of changes in population size can be severely biased if factors related to the acquisition of data are not adequately controlled for. In particular we identify two types of observer effects: these correspond to baseline differences in observer competence, and to changes through time in the ability of individual observers. We present a family of models for count data in which the first of these observer effects is treated as a nuisance parameter. Conditioning on totals of negative binomial counts yields a Dirichlet compound multinomial vector for each observer. Quasi-likelihood is used to estimate parameters related to population trajectory and other parameters of interest; model selection is carried out on the basis of Akaike's information criterion. An example is presented using data on Wood thrush from the North American Breeding Bird Survey.

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

Treesearch

Thomas C. Marcin

1974-01-01

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

Population dynamics of Greater Scaup breeding on the Yukon-Kuskokwim Delta, Alaska

USGS Publications Warehouse

Flint, Paul L.; Grand, J. Barry; Fondell, Thomas F.; Morse, Julie A.

2006-01-01

Using a stochastic model, we estimated that, on average, breeding females produced 0.57 young females/nesting season. We combined this estimate of productivity with our annual estimates of adult survival and an assumed population growth rate of 1.0, then solved for an estimate of first-year survival (0.40). Under these conditions the predicted stable age distribution of breeding females (i.e., the nesting population) was 15.1% 1-year-old, 4.1% 2-year-old first-time breeders, and 80.8% 2-year-old and older, experienced breeders. We subjected this stochastic model to perturbation analyses to examine the relative effects of demographic parameters on k. The relative effects of productivity and adult survival on the population growth rate were 0.26 and 0.72, respectively. Thus, compared to productivity, proportionally equivalent changes in annual survival would have 2.8 times the effect on k. However, when we examined annual variation in predicted population size using standardized regression coefficients, productivity explained twice as much variation as annual survival. Thus, management actions focused on changes in survival or productivity have the ability to influence population size; however, substantially larger changes in productivity are required to influence population trends.

Food provisioning alters infection dynamics in populations of a wild rodent

PubMed Central

Forbes, Kristian M.; Henttonen, Heikki; Hirvelä-Koski, Varpu; Kipar, Anja; Mappes, Tapio; Stuart, Peter; Huitu, Otso

2015-01-01

While pathogens are often assumed to limit the growth of wildlife populations, experimental evidence for their effects is rare. A lack of food resources has been suggested to enhance the negative effects of pathogen infection on host populations, but this theory has received little investigation. We conducted a replicated two-factor enclosure experiment, with introduction of the bacterium Bordetella bronchiseptica and food supplementation, to evaluate the individual and interactive effects of pathogen infection and food availability on vole populations during a boreal winter. We show that prior to bacteria introduction, vole populations were limited by food availability. Bordetella bronchiseptica introduction then reduced population growth and abundance, but contrary to predictions, primarily in food supplemented populations. Infection prevalence and pathological changes in vole lungs were most common in food supplemented populations, and are likely to have resulted from increased congregation and bacteria transmission around feeding stations. Bordetella bronchiseptica-infected lungs often showed protozoan co-infection (consistent with Hepatozoon erhardovae), together with more severe inflammatory changes. Using a multidisciplinary approach, this study demonstrates a complex picture of interactions and underlying mechanisms, leading to population-level effects. Our results highlight the potential for food provisioning to markedly influence disease processes in wildlife mammal populations. PMID:26446813

Local variability mediates vulnerability of trout populations to land use and climate change

Treesearch

Brooke E. Penaluna; Jason B. Dunham; Steve F. Railsback; Ivan Arismendi; Sherri L. Johnson; Robert E. Bilby; Mohammad Safeeq; Arne E. Skaugset; James P. Meador

2015-01-01

Land use and climate change occur simultaneously around the globe. Fully understanding their separate and combined effects requires a mechanistic understanding at the local scale where their effects are ultimately realized. Here we applied an individual-based model of fish population dynamics to evaluate the role of local stream variability in modifying responses of...

Effects of habitat change along Breeding Bird Survey routes in the central Appalachians on Cerulean Warbler population

USGS Publications Warehouse

McElhone, P.; Wood, P.W.; Dawson, D.

2007-01-01

The cerulean warbler (Dendroica cerulea) is one of the highest priority bird species in the eastern United States because populations have declined 4.3% annually during 1966?2005 based on Breeding Bird Survey (BBS) data. Habitat loss and fragmentation due to land use changes is thought to be one of the major factors contributing to the decline. BBS routes, the primary source for monitoring bird population trends, include 50 sampling stops every 0.8 km. Although data from BBS routes are extrapolated to determine regional trends in bird populations, it is important to understand the effects of habitat changes at the stop-level along BBS routes. Route-level analysis of habitat changes may mask important changes that are occurring at a smaller scale particularly for the cerulean warbler which displays several micro-scale habitat preferences. We are examining cerulean warbler habitat and population changes in its core breeding range of the Ohio Hills and Cumberland Plateau physiographic regions. We quantified land cover changes within 300 m of BBS routes in the core cerulean warbler breeding range of Ohio, West Virginia, and Kentucky by digitizing aerial photographs from two time periods: the 1980s and 2004. We also quantified land cover changes within 300 m of BBS routes with the National Land Cover Dataset (NLCD) from 1992 and 2001. The hand-digitized aerial photos will be compared with the NLCD to determine how similar the two methods are in quantifying land cover changes. We then compared stop-level land cover changes with stop level changes in cerulean warbler detections within the same time periods along the BBS routes. This will allow for a more detailed analysis of how well habitat changes along BBS routes reflect the changes in cerulean warbler populations.

Integrating environmental and genetic effects to predict responses of tree populations to climate.

PubMed

Wang, Tongli; O'Neill, Gregory A; Aitken, Sally N

2010-01-01

Climate is a major environmental factor affecting the phenotype of trees and is also a critical agent of natural selection that has molded among-population genetic variation. Population response functions describe the environmental effect of planting site climates on the performance of a single population, whereas transfer functions describe among-population genetic variation molded by natural selection for climate. Although these approaches are widely used to predict the responses of trees to climate change, both have limitations. We present a novel approach that integrates both genetic and environmental effects into a single "universal response function" (URF) to better predict the influence of climate on phenotypes. Using a large lodgepole pine (Pinus contorta Dougl. ex Loud.) field transplant experiment composed of 140 populations planted on 62 sites to demonstrate the methodology, we show that the URF makes full use of data from provenance trials to: (1) improve predictions of climate change impacts on phenotypes; (2) reduce the size and cost of future provenance trials without compromising predictive power; (3) more fully exploit existing, less comprehensive provenance tests; (4) quantify and compare environmental and genetic effects of climate on population performance; and (5) predict the performance of any population growing in any climate. Finally, we discuss how the last attribute allows the URF to be used as a mechanistic model to predict population and species ranges for the future and to guide assisted migration of seed for reforestation, restoration, or afforestation and genetic conservation in a changing climate.

A stochastic population model to evaluate Moapa dace (Moapa coriacea) population growth under alternative management scenarios

USGS Publications Warehouse

Perry, Russell W.; Jones, Edward; Scoppettone, G. Gary

2015-07-14

Increasing or decreasing the total carrying capacity of all stream segments resulted in changes in equilibrium population size that were directly proportional to the change in capacity. However, changes in carrying capacity to some stream segments but not others could result in disproportionate changes in equilibrium population sizes by altering density-dependent movement and survival in the stream network. These simulations show how our IBM can provide a useful management tool for understanding the effect of restoration actions or reintroductions on carrying capacity, and, in turn, how these changes affect Moapa dace abundance. Such tools are critical for devising management strategies to achieve recovery goals.

Climate change and temperature-dependent sex determination: can individual plasticity in nesting phenology prevent extreme sex ratios?

PubMed

Schwanz, Lisa E; Janzen, Fredric J

2008-01-01

Under temperature-dependent sex determination (TSD), temperatures experienced by embryos during development determine the sex of the offspring. Consequently, populations of organisms with TSD have the potential to be strongly impacted by climatic warming that could bias offspring sex ratio, a fundamental demographic parameter involved in population dynamics. Moreover, many taxa with TSD are imperiled, so research on this phenomenon, particularly long-term field study, has assumed great urgency. Recently, turtles with TSD have joined the diverse list of taxa that have demonstrated population-level changes in breeding phenology in response to recent climate change. This raises the possibility that any adverse impacts of climate change on populations may be alleviated by individual plasticity in nesting phenology. Here, we examine data from a long-term study on a population of painted turtles (Chrysemys picta) to determine whether changes in phenology are due to individual plasticity and whether individual plasticity in the timing of nesting has the capacity to offset the sex ratio effects of a rise in climatic temperature. We find that individual females show plasticity in the date of first nesting each year, and that this plasticity depends on the climate from the previous winter. First nesting date is not repeatable within individuals, suggesting that it would not respond to selection. Sex ratios of hatchlings within a nest declined nonsignificantly over the nesting season. However, small increases in summer temperature had a much stronger effect on nest sex ratios than did laying nests earlier in the season. For this and other reasons, it seems unlikely that individual plasticity in the timing of nesting will offset the effects of climate change on sex ratios in this population, and we hypothesize that this conclusion applies to other populations with TSD.

Shaping Policy Change in Population Health: Policy Entrepreneurs, Ideas, and Institutions

PubMed Central

Béland, Daniel; Katapally, Tarun R.

2018-01-01

Political realities and institutional structures are often ignored when gathering evidence to influence population health policies. If these policies are to be successful, social science literature on policy change should be integrated into the population health approach. In this contribution, drawing on the work of John W. Kingdon and related scholarship, we set out to examine how key components of the policy change literature could contribute towards the effective development of population health policies. Shaping policy change would require a realignment of the existing school of thought, where the contribution of population health seems to end at knowledge translation. Through our critical analysis of selected literature, we extend recommendations to advance a burgeoning discussion in adopting new approaches to successfully implement evidence-informed population health policies. PMID:29764101

The uncertainty of future water supply adequacy in megacities: Effects of population growth and climate change

NASA Astrophysics Data System (ADS)

Alarcon, T.; Garcia, M. E.; Small, D. L.; Portney, K.; Islam, S.

2013-12-01

Providing water to the expanding population of megacities, which have over 10 million people, with a stressed and aging water infrastructure creates unprecedented challenges. These challenges are exacerbated by dwindling supply and competing demands, altered precipitation and runoff patterns in a changing climate, fragmented water utility business models, and changing consumer behavior. While there is an extensive literature on the effects of climate change on water resources, the uncertainty of climate change predictions continues to be high. This hinders the value of these predictions for municipal water supply planning. The ability of water utilities to meet future water needs will largely depend on their capacity to make decisions under uncertainty. Water stressors, like changes in demographics, climate, and socioeconomic patterns, have varying degrees of uncertainty. Identifying which stressors will have a greater impact on water resources, may reduce the level of future uncertainty for planning and managing water utilities. Within this context, we analyze historical and projected changes of population and climate to quantify the relative impacts of these two stressors on water resources. We focus on megacities that rely primarily on surface water resources to evaluate (a) population growth pattern from 1950-2010 and projected population for 2010-2060; (b) climate change impact on projected climate change scenarios for 2010-2060; and (c) water access for 1950-2010; projected needs for 2010-2060.

Hierarchical model analysis of the Atlantic Flyway Breeding Waterfowl Survey

USGS Publications Warehouse

Sauer, John R.; Zimmerman, Guthrie S.; Klimstra, Jon D.; Link, William A.

2014-01-01

We used log-linear hierarchical models to analyze data from the Atlantic Flyway Breeding Waterfowl Survey. The survey has been conducted by state biologists each year since 1989 in the northeastern United States from Virginia north to New Hampshire and Vermont. Although yearly population estimates from the survey are used by the United States Fish and Wildlife Service for estimating regional waterfowl population status for mallards (Anas platyrhynchos), black ducks (Anas rubripes), wood ducks (Aix sponsa), and Canada geese (Branta canadensis), they are not routinely adjusted to control for time of day effects and other survey design issues. The hierarchical model analysis permits estimation of year effects and population change while accommodating the repeated sampling of plots and controlling for time of day effects in counting. We compared population estimates from the current stratified random sample analysis to population estimates from hierarchical models with alternative model structures that describe year to year changes as random year effects, a trend with random year effects, or year effects modeled as 1-year differences. Patterns of population change from the hierarchical model results generally were similar to the patterns described by stratified random sample estimates, but significant visibility differences occurred between twilight to midday counts in all species. Controlling for the effects of time of day resulted in larger population estimates for all species in the hierarchical model analysis relative to the stratified random sample analysis. The hierarchical models also provided a convenient means of estimating population trend as derived statistics from the analysis. We detected significant declines in mallard and American black ducks and significant increases in wood ducks and Canada geese, a trend that had not been significant for 3 of these 4 species in the prior analysis. We recommend using hierarchical models for analysis of the Atlantic Flyway Breeding Waterfowl Survey.

Endogenous technological and population change under increasing water scarcity

NASA Astrophysics Data System (ADS)

Pande, S.; Ertsen, M.; Sivapalan, M.

2013-11-01

The ancient civilization in the Indus Valley civilization dispersed under extreme dry conditions; there are indications that the same holds for many other ancient societies. Even contemporary societies, such as the one in Murrumbidgee river basin in Australia, have started to witness a decline in overall population under increasing water scarcity. Hydroclimatic change may not be the sole predictor of the fate of contemporary societies in water scarce regions and many critics of such (perceived) hydroclimatic determinism have suggested that technological change may ameliorate the effects of increasing water scarcity and as such counter the effects of hydroclimatic changes. To study the role of technological change on the dynamics of coupled human-water systems, we develop a simple overlapping-generations model of endogenous technological and demographic change. We model technological change as an endogenous process that depends on factors such as the investments that are (endogenously) made in a society, the (endogenous) diversification of a society into skilled and unskilled workers, a society's patience in terms of its present consumption vs. future consumption, production technology and the (endogenous) interaction of all of these factors. In the model the population growth rate is programmed to decline once consumption per capita crosses a "survival" threshold. This means we do not treat technology as an exogenous random sequence of events, but instead assume that it results (endogenously) from societal actions. The model demonstrates that technological change may indeed ameliorate the effects of increasing water scarcity but typically it does so only to a certain extent. It is possible that technological change may allow a society to escape the effect of increasing water scarcity, leading to a (super)-exponential rise in technology and population. However, such cases require the rate of success of investment in technological advancement to be high. In other more realistic cases of technological success, we find that endogenous technology change only helps to delay the peak of population size before it inevitably starts to decline. While the model is a rather simple model of societal development, it is shown to be capable of replicating patterns of technological and population changes. It is capable of replicating the pattern of declining consumption per capita in presence of growth in aggregate production. It is also capable of replicating an exponential population rise, even under increasing water scarcity. The results of the model suggest that societies that declined or are declining in the face of extreme water scarcity may have done so due to slower rate of success of investment in technological advancement. The model suggests that the population decline occurs after a prolonged decline in consumption per capita, which in turn is due to the joint effect of initially increasing population and increasing water scarcity. This is despite technological advancement and increase in aggregate production. We suggest that declining consumption per capita despite technological advancement and increase in aggregate production may serve as a useful predictor of upcoming decline in contemporary societies in water scarce basins.

Transplant experiments uncover Baltic Sea basin-specific responses in bacterioplankton community composition and metabolic activities.

PubMed

Lindh, Markus V; Figueroa, Daniela; Sjöstedt, Johanna; Baltar, Federico; Lundin, Daniel; Andersson, Agneta; Legrand, Catherine; Pinhassi, Jarone

2015-01-01

Anthropogenically induced changes in precipitation are projected to generate increased river runoff to semi-enclosed seas, increasing loads of terrestrial dissolved organic matter and decreasing salinity. To determine how bacterial community structure and functioning adjust to such changes, we designed microcosm transplant experiments with Baltic Proper (salinity 7.2) and Bothnian Sea (salinity 3.6) water. Baltic Proper bacteria generally reached higher abundances than Bothnian Sea bacteria in both Baltic Proper and Bothnian Sea water, indicating higher adaptability. Moreover, Baltic Proper bacteria growing in Bothnian Sea water consistently showed highest bacterial production and beta-glucosidase activity. These metabolic responses were accompanied by basin-specific changes in bacterial community structure. For example, Baltic Proper Pseudomonas and Limnobacter populations increased markedly in relative abundance in Bothnian Sea water, indicating a replacement effect. In contrast, Roseobacter and Rheinheimera populations were stable or increased in abundance when challenged by either of the waters, indicating an adjustment effect. Transplants to Bothnian Sea water triggered the initial emergence of particular Burkholderiaceae populations, and transplants to Baltic Proper water triggered Alteromonadaceae populations. Notably, in the subsequent re-transplant experiment, a priming effect resulted in further increases to dominance of these populations. Correlated changes in community composition and metabolic activity were observed only in the transplant experiment and only at relatively high phylogenetic resolution. This suggested an importance of successional progression for interpreting relationships between bacterial community composition and functioning. We infer that priming effects on bacterial community structure by natural episodic events or climate change induced forcing could translate into long-term changes in bacterial ecosystem process rates.

Transplant experiments uncover Baltic Sea basin-specific responses in bacterioplankton community composition and metabolic activities

PubMed Central

Lindh, Markus V.; Figueroa, Daniela; Sjöstedt, Johanna; Baltar, Federico; Lundin, Daniel; Andersson, Agneta; Legrand, Catherine; Pinhassi, Jarone

2015-01-01

Anthropogenically induced changes in precipitation are projected to generate increased river runoff to semi-enclosed seas, increasing loads of terrestrial dissolved organic matter and decreasing salinity. To determine how bacterial community structure and functioning adjust to such changes, we designed microcosm transplant experiments with Baltic Proper (salinity 7.2) and Bothnian Sea (salinity 3.6) water. Baltic Proper bacteria generally reached higher abundances than Bothnian Sea bacteria in both Baltic Proper and Bothnian Sea water, indicating higher adaptability. Moreover, Baltic Proper bacteria growing in Bothnian Sea water consistently showed highest bacterial production and beta-glucosidase activity. These metabolic responses were accompanied by basin-specific changes in bacterial community structure. For example, Baltic Proper Pseudomonas and Limnobacter populations increased markedly in relative abundance in Bothnian Sea water, indicating a replacement effect. In contrast, Roseobacter and Rheinheimera populations were stable or increased in abundance when challenged by either of the waters, indicating an adjustment effect. Transplants to Bothnian Sea water triggered the initial emergence of particular Burkholderiaceae populations, and transplants to Baltic Proper water triggered Alteromonadaceae populations. Notably, in the subsequent re-transplant experiment, a priming effect resulted in further increases to dominance of these populations. Correlated changes in community composition and metabolic activity were observed only in the transplant experiment and only at relatively high phylogenetic resolution. This suggested an importance of successional progression for interpreting relationships between bacterial community composition and functioning. We infer that priming effects on bacterial community structure by natural episodic events or climate change induced forcing could translate into long-term changes in bacterial ecosystem process rates. PMID:25883589

Effects of precipitation change and neighboring plants on population dynamics of Bromus tectorum.

PubMed

Prevéy, Janet S; Seastedt, Timothy R

2015-11-01

Shifting precipitation patterns resulting from global climate change will influence the success of invasive plant species. In the Front Range of Colorado, Bromus tectorum (cheatgrass) and other non-native winter annuals have invaded grassland communities and are becoming more abundant. As the global climate warms, more precipitation may fall as rain rather than snow in winter, and an increase in winter rain could benefit early-growing winter annuals, such as B. tectorum, to the detriment of native species. In this study we measured the effects of simulated changes in seasonal precipitation and presence of other plant species on population growth of B. tectorum in a grassland ecosystem near Boulder, Colorado, USA. We also performed elasticity analyses to identify life transitions that were most sensitive to precipitation differences. In both study years, population growth rates were highest for B. tectorum growing in treatments receiving supplemental winter precipitation and lowest for those receiving the summer drought treatment. Survival of seedlings to flowering and seed production contributed most to population growth in all treatments. Biomass of neighboring native plants was positively correlated with reduced population growth rates of B. tectorum. However, exotic plant biomass had no effect on population growth rates. This study demonstrates how interacting effects of climate change and presence of native plants can influence the population growth of an invasive species. Overall, our results suggest that B. tectorum will become more invasive in grasslands if the seasonality of precipitation shifts towards wetter winters and allows B. tectorum to grow when competition from native species is low.

Height-growth response to climatic changes differs among populations of Douglas-fir: A novel analysis of historic data

Treesearch

Laura P. Leites; Andrew P. Robinson; Gerald E. Rehfeldt; John D. Marshall; Nicholas L. Crookston

2012-01-01

Projected climate change will affect existing forests, as substantial changes are predicted to occur during their life spans. Species that have ample intraspecific genetic differentiation, such as Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), are expected to display population-specific growth responses to climate change. Using a mixed-effects modeling approach,...

Outward migration may alter population dynamics and income inequality

NASA Astrophysics Data System (ADS)

Shayegh, Soheil

2017-11-01

Climate change impacts may drive affected populations to migrate. However, migration decisions in response to climate change could have broader effects on population dynamics in affected regions. Here, I model the effect of climate change on fertility rates, income inequality, and human capital accumulation in developing countries, focusing on the instrumental role of migration as a key adaptation mechanism. In particular, I investigate how climate-induced migration in developing countries will affect those who do not migrate. I find that holding all else constant, climate change raises the return on acquiring skills, because skilled individuals have greater migration opportunities than unskilled individuals. In response to this change in incentives, parents may choose to invest more in education and have fewer children. This may ultimately reduce local income inequality, partially offsetting some of the damages of climate change for low-income individuals who do not migrate.

Can legislation provide a better match between demand and supply in psychotherapy?

PubMed

Springer-Kremser, Marianne; Eder, Anselm; Jandl-Jager, Elisabeth; Hager, Isabella

2002-10-01

There is evidence showing that psychotherapy very often does not reach the persons most in need of it. A change in patterns of "consumer behaviour" is difficult to achieve on the basis of individual behavioural change. Can it be achieved by changes in legislation? By comparing socio-demographic criteria of patients seen at the University Clinic of Psychoanalysis and Psychotherapy between 1990 and 1996, we are able to give some evidence that changes in legislation, concerning psychotherapy, which took place in the years 1991, 1994 and 1995, had a significant effect on the socio-demographic composition of our patient population, showing a convergence of patient population towards the socio-demographic criteria of the population of Vienna. We argue that the changes in legislation in Austria, concerning funding of psychotherapy, and introducing a new profession "psychotherapist", have a measurable effect which works in two ways: 1) direct effect: decreased financial charge of patients; 2) indirect effect: increased motivation of patients, resulting from a reduction in stigmas attached to the role of "psychiatric patient".

Demographic aspects of climate change mitigation and adaptation.

PubMed

Lutz, Wolfgang; Striessnig, Erich

2015-01-01

This paper addresses the contribution of changes in population size and structures to greenhouse gas emissions and to the capacity to adapt to climate change. The paper goes beyond the conventional focus on the changing composition by age and sex. It does so by addressing explicitly the changing composition of the population by level of educational attainment, taking into account new evidence about the effect of educational attainment in reducing significantly the vulnerability of populations to climatic challenges. This evidence, which has inspired a new generation of socio-economic climate change scenarios, is summarized. While the earlier IPCC-SRES (Intergovernmental Panel on Climate Change-Special Report on Emissions Scenarios) scenarios only included alternative trajectories for total population size (treating population essentially as a scaling parameter), the Shared Socio-economic Pathways (SSPs) in the new scenarios were designed to capture the socio-economic challenges to climate change mitigation and adaptation, and include full age, sex, and education details for all countries.

Beyond climate envelopes: effects of weather on regional population trends in butterflies.

PubMed

WallisDeVries, Michiel F; Baxter, Wendy; Van Vliet, Arnold J H

2011-10-01

Although the effects of climate change on biodiversity are increasingly evident by the shifts in species ranges across taxonomical groups, the underlying mechanisms affecting individual species are still poorly understood. The power of climate envelopes to predict future ranges has been seriously questioned in recent studies. Amongst others, an improved understanding of the effects of current weather on population trends is required. We analysed the relation between butterfly abundance and the weather experienced during the life cycle for successive years using data collected within the framework of the Dutch Butterfly Monitoring Scheme for 40 species over a 15-year period and corresponding climate data. Both average and extreme temperature and precipitation events were identified, and multiple regression was applied to explain annual changes in population indices. Significant weather effects were obtained for 39 species, with the most frequent effects associated with temperature. However, positive density-dependence suggested climatic independent trends in at least 12 species. Validation of the short-term predictions revealed a good potential for climate-based predictions of population trends in 20 species. Nevertheless, data from the warm and dry year of 2003 indicate that negative effects of climatic extremes are generally underestimated for habitat specialists in drought-susceptible habitats, whereas generalists remain unaffected. Further climatic warming is expected to influence the trends of 13 species, leading to an improvement for nine species, but a continued decline in the majority of species. Expectations from climate envelope models overestimate the positive effects of climate change in northwestern Europe. Our results underline the challenge to include population trends in predicting range shifts in response to climate change.

Using high-resolution satellite imagery to assess populations of animals in the Antarctic

NASA Astrophysics Data System (ADS)

LaRue, Michelle Ann

The Southern Ocean is one of the most rapidly-changing ecosystems on the planet due to the effects of climate change and commercial fishing for ecologically-important krill and fish. It is imperative that populations of indicator species, such as penguins and seals, be monitored at regional- to global scales to decouple the effects of climate and anthropogenic changes for appropriate ecosystem-based management of the Southern Ocean. Remotely monitoring populations through high-resolution satellite imagery is currently the only feasible way to gain information about population trends of penguins and seals in Antarctica. In my first chapter, I review the literature where high-resolution satellite imagery has been used to assess populations of animals in polar regions. Building on this literature, my second chapter focuses on estimating changes in abundance in the Weddell seal population in Erebus Bay. I found a strong correlation between ground and satellite counts, and this finding provides an alternate method for assessing populations of Weddell seals in areas where less is known about population status. My third chapter explores how size of the guano stain of Adelie penguins can be used to predict population size. Using high-resolution imagery and ground counts, I built a model to estimate the breeding population of Adelie penguins using a supervised classification to estimate guano size. These results suggest that the size of guano stain is an accurate predictor of population size, and can be applied to estimate remote Adelie penguin colonies. In my fourth chapter, I use air photos, satellite imagery, climate and mark-resight data to determine that climate change has positively impacted the population of Adelie penguins at Beaufort Island through a habitat release that ultimately affected the dynamics within the southern Ross Sea metapopulation. Finally, for my fifth chapter I combined the literature with observations from aerial surveys and satellite imagery to determine that emperor penguins are not philopatric. These results have implications for interpreting long-term modeling studies and I suggest that future research should account for metapopulation dynamics within emperor penguin populations. Combined, my dissertation provides resources and new insights for effective management of the Southern Ocean ecosystem.

Canine parvovirus effect on wolf population change and pup survival

USGS Publications Warehouse

Mech, L.D.; Goyal, S.M.

1993-01-01

Canine parvovirus infected wild canids more than a decade ago, but no population effect has been documented. In wild Minnesota wolves (Canis lupus) over a 12-yr period, the annual percent population increase and proportion of pups each were inversely related to the percentage of wolves serologically positive to the disease. Although these effects did not seem to retard this large extant population, similar relationships in more isolated wolf populations might hinder recovery of this endangered and threatened species.

Understanding how lake populations of arctic char are structured and function with special consideration of the potential effects of climate change: a multi-faceted approach.

PubMed

Budy, Phaedra; Luecke, Chris

2014-09-01

Size dimorphism in fish populations, both its causes and consequences, has been an area of considerable focus; however, uncertainty remains whether size dimorphism is dynamic or stabilizing and about the role of exogenous factors. Here, we explored patterns among empirical vital rates, population structure, abundance and trend, and predicted the effects of climate change on populations of arctic char (Salvelinus alpinus) in two lakes. Both populations cycle dramatically between dominance by small (≤300 mm) and large (>300 mm) char. Apparent survival (Φ) and specific growth rates (SGR) were relatively high (40-96%; SGR range 0.03-1.5%) and comparable to those of conspecifics at lower latitudes. Climate change scenarios mimicked observed patterns of warming and resulted in temperatures closer to optimal for char growth (15.15 °C) and a longer growing season. An increase in consumption rates (28-34%) under climate change scenarios led to much greater growth rates (23-34%). Higher growth rates predicted under climate change resulted in an even greater predicted amplitude of cycles in population structure as well as an increase in reproductive output (Ro) and decrease in generation time (Go). Collectively, these results indicate arctic char populations (not just individuals) are extremely sensitive to small changes in the number of ice-free days. We hypothesize years with a longer growing season, predicted to occur more often under climate change, produce elevated growth rates of small char and act in a manner similar to a "resource pulse," allowing a sub-set of small char to "break through," thus setting the cycle in population structure.

Understanding how lake populations of arctic char are structured and function with special consideration of the potential effects of climate change: A multi-faceted approach.

USGS Publications Warehouse

Budy, Phaedra; Luecke, Chris

2014-01-01

Size dimorphism in fish populations, both its causes and consequences, has been an area of considerable focus; however, uncertainty remains whether size dimorphism is dynamic or stabilizing and about the role of exogenous factors. Here, we explored patterns among empirical vital rates, population structure, abundance and trend, and predicted the effects of climate change on populations of arctic char (Salvelinus alpinus) in two lakes. Both populations cycle dramatically between dominance by small (≤300 mm) and large (>300 mm) char. Apparent survival (Φ) and specific growth rates (SGR) were relatively high (40–96 %; SGR range 0.03–1.5 %) and comparable to those of conspecifics at lower latitudes. Climate change scenarios mimicked observed patterns of warming and resulted in temperatures closer to optimal for char growth (15.15 °C) and a longer growing season. An increase in consumption rates (28–34 %) under climate change scenarios led to much greater growth rates (23–34 %). Higher growth rates predicted under climate change resulted in an even greater predicted amplitude of cycles in population structure as well as an increase in reproductive output (Ro) and decrease in generation time (Go). Collectively, these results indicate arctic char populations (not just individuals) are extremely sensitive to small changes in the number of ice-free days. We hypothesize years with a longer growing season, predicted to occur more often under climate change, produce elevated growth rates of small char and act in a manner similar to a “resource pulse,” allowing a sub-set of small char to “break through,” thus setting the cycle in population structure.

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

PubMed

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.

Changes in Visual Function in the Elderly Population in the United States: 1995-2010.

PubMed

Chen, Yiqun; Hahn, Paul; Sloan, Frank A

2016-06-01

To document recent trends in visual function among the United States population aged 70+ years and investigate how the trends can be explained by inter-temporal changes in: (1) population sociodemographic characteristics, and chronic disease prevalence, including eye diseases (compositional changes); and (2) effects of the above factors on visual function (structural changes). Data from the 1995 Asset and Health Dynamics among the Oldest Old (AHEAD) and the 2010 Health and Retirement Study (HRS) were merged with Medicare Part B claims in the interview years and the 2 previous years. Decomposition analysis was performed. Respondents from both studies were aged 70+ years. The outcome measure was respondent self-reported visual function on a 6-point scale (from 6 = blind to 1 = excellent). Overall, visual function improved from slightly worse than good (3.14) in 1995 to slightly better than good (2.98) in 2010. A decline in adverse effects of aging on vision was found. Among the compositional changes were higher educational attainment leading to improved vision, and higher prevalence of such diseases as diabetes mellitus, which tended to lower visual function. However, compared to compositional changes, structural changes were far more important, including decreased adverse effects of aging, diabetes mellitus (when not controlling for eye diseases), and diagnosed glaucoma. Although the US population has aged and is expected to age further, visual function improved among elderly persons, especially among persons 80+ years, likely reflecting a favorable role of structural changes identified in this study in mitigating the adverse effect of ongoing aging on vision.

Population and energy elasticity of tornado casualties

NASA Astrophysics Data System (ADS)

Fricker, Tyler; Elsner, James B.; Jagger, Thomas H.

2017-04-01

Tornadoes are capable of catastrophic destruction and mass casualties, but there are yet no estimates of how sensitive the number of casualties are to changes in the number of people in harm's way or to changes in tornado energy. Here the relationship between tornado casualties (deaths and injuries), population, and energy dissipation is quantified using the economic concept of "elasticity." Records of casualties from individual tornadoes over the period 2007-2015 are fit to a regression model. The coefficient on the population term (population elasticity) indicates that a doubling in population increases the casualty rate by 21% [(17, 24)%, 95% credible interval]. The coefficient on the energy term (energy elasticity) indicates that a doubling in energy dissipation leads to a 33% [(30, 35)%, 95% credible interval] increase in the casualty rate. The difference in elasticity values show that on average, changes in energy dissipation have been relatively more important in explaining tornado casualties than changes in population. Assuming no changes in warning effectiveness or mitigation efforts, these elasticity estimates can be used to project changes in casualties given the known population trends and possible trends in tornado activity.

40 CFR 230.75 - Actions affecting plant and animal populations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Actions affecting plant and animal... Actions To Minimize Adverse Effects § 230.75 Actions affecting plant and animal populations. Minimization of adverse effects on populations of plants and animals can be achieved by: (a) Avoiding changes in...

40 CFR 230.75 - Actions affecting plant and animal populations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Actions affecting plant and animal... Actions To Minimize Adverse Effects § 230.75 Actions affecting plant and animal populations. Minimization of adverse effects on populations of plants and animals can be achieved by: (a) Avoiding changes in...

40 CFR 230.75 - Actions affecting plant and animal populations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Actions affecting plant and animal... Actions To Minimize Adverse Effects § 230.75 Actions affecting plant and animal populations. Minimization of adverse effects on populations of plants and animals can be achieved by: (a) Avoiding changes in...

40 CFR 230.75 - Actions affecting plant and animal populations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Actions affecting plant and animal... Actions To Minimize Adverse Effects § 230.75 Actions affecting plant and animal populations. Minimization of adverse effects on populations of plants and animals can be achieved by: (a) Avoiding changes in...

Integrating Science, Mathematics, and Sociology in an Inquiry-Based Study of Changing Population Density.

ERIC Educational Resources Information Center

Schlenker, Richard M.; Schlenker, Karl R.

2000-01-01

Presents a five-activity sequence designed to help students understand the effects of population doubling. Activities consider the effects of population doubling on human interactions, drinking water supplies, and food supply. Students also develop graphs of data and write research papers. (WRM)

Can migration mitigate the effects of ecosystem change? Patterns of dispersal, energy acquisition and allocation in Great Lakes lake whitefish (Coregonus clupeaformis)

USGS Publications Warehouse

Rennie, Michael D.; Ebener, Mark P.; Wagner, Tyler

2012-01-01

Migration can be a behavioural response to poor or declining home range habitat quality and can occur when the costs of migration are overcome by the benefi ts of encountering higher-quality resources elsewhere. Despite dramatic ecosystem-level changes in the benthic food web of the Laurentian Great Lakes since the colonization of dreissenid mussels, coincident changes in condition and growth rates among benthivorous lake whitefi sh populations have been variable. We hypothesized that this variation could be in part mitigated by differences in migratory habits among populations, where increased migration distance can result in an increased probability of encountering high-quality habitat (relative to the home range). Results from four Great Lakes populations support this hypothesis; relative growth rates increased regularly with migration distance. The population with the largest average migration distance also had the least reduction in size-at-age during a period of signifi cant ecosystem change and among the highest estimated consumption and activity rates. In comparison, the population with the greatest declines in size-at-age was among the least mobile, demonstrating only moderate rates of consumption and activity. The least mobile population of lake whitefi sh was supported by a remnant Diporeia population and has experienced only moderate temporal growth declines. Our study provides evidence for the potential role of migration in mitigating the effects of ecosystem change on lake whitefi sh populations.

Food provisioning alters infection dynamics in populations of a wild rodent.

PubMed

Forbes, Kristian M; Henttonen, Heikki; Hirvelä-Koski, Varpu; Kipar, Anja; Mappes, Tapio; Stuart, Peter; Huitu, Otso

2015-10-07

While pathogens are often assumed to limit the growth of wildlife populations, experimental evidence for their effects is rare. A lack of food resources has been suggested to enhance the negative effects of pathogen infection on host populations, but this theory has received little investigation. We conducted a replicated two-factor enclosure experiment, with introduction of the bacterium Bordetella bronchiseptica and food supplementation, to evaluate the individual and interactive effects of pathogen infection and food availability on vole populations during a boreal winter. We show that prior to bacteria introduction, vole populations were limited by food availability. Bordetella bronchiseptica introduction then reduced population growth and abundance, but contrary to predictions, primarily in food supplemented populations. Infection prevalence and pathological changes in vole lungs were most common in food supplemented populations, and are likely to have resulted from increased congregation and bacteria transmission around feeding stations. Bordetella bronchiseptica-infected lungs often showed protozoan co-infection (consistent with Hepatozoon erhardovae), together with more severe inflammatory changes. Using a multidisciplinary approach, this study demonstrates a complex picture of interactions and underlying mechanisms, leading to population-level effects. Our results highlight the potential for food provisioning to markedly influence disease processes in wildlife mammal populations. © 2015 The Author(s).

Current and Future Effects of Climate Change on Montane Amphibians

NASA Astrophysics Data System (ADS)

Corn, S.

2002-05-01

Breeding phenology of amphibians in inextricably linked to weather, and change in the timing of breeding resulting from climate change may have consequences for the fitness of individuals and may affect persistence of amphibian populations. Amphibians in some north temperate locations have been observed to breed earlier in recent years in response to warmer spring temperatures, but this is not a universal phenomenon. In mountain populations, phenology is influenced by snow deposition as much as temperature. A trend towards earlier breeding, associated with increasing El Niño frequency, may be occurring in the Cascade Mountains in Oregon, but only at lower elevations. There is no evidence for changes in the dates of breeding activity by amphibians in the Rocky Mountains. Too few amphibian species have been studied, and those for which data exist have been studied for too brief a span of years to allow general conclusions about the effects of climate change. However, regardless of whether climate change has contributed to current amphibian declines, changes in temperature and the extent and duration of snow cover predicted for the next century will have increasingly severe consequences for the persistence of some species. Additional observations from amphibian populations, and spatial and temporal modeling of climate variables are needed to generate predictions of past and future breeding phenology, and the effects on amphibian population dynamics.

Latitudinal-Related Variation in Wintering Population Trends of Greylag Geese (Anser Anser) along the Atlantic Flyway: A Response to Climate Change?

PubMed

Ramo, Cristina; Amat, Juan A; Nilsson, Leif; Schricke, Vincent; Rodríguez-Alonso, Mariano; Gómez-Crespo, Enrique; Jubete, Fernando; Navedo, Juan G; Masero, José A; Palacios, Jesús; Boos, Mathieu; Green, Andy J

2015-01-01

The unusually high quality of census data for large waterbirds in Europe facilitates the study of how population change varies across a broad geographical range and relates to global change. The wintering population of the greylag goose Anser anser in the Atlantic flyway spanning between Sweden and Spain has increased from 120 000 to 610 000 individuals over the past three decades, and expanded its wintering range northwards. Although population sizes recorded in January have increased in all seven countries in the wintering range, we found a pronounced northwards latitudinal effect in which the rate of increase is higher at greater latitudes, causing a constant shift in the centre of gravity for the spatial distribution of wintering geese. Local winter temperatures have a strong influence on goose numbers but in a manner that is also dependent on latitude, with the partial effect of temperature (while controlling for the increasing population trend between years) being negative at the south end and positive at the north end of the flyway. Contrary to assumptions in the literature, the expansion of crops exploited by greylag geese has made little contribution to the increases in population size. Only in one case (expansion of winter cereals in Denmark) did we find evidence of an effect of changing land use. The expanding and shifting greylag population is likely to have increasing impacts on habitats in northern Europe during the course of this century.

Review of behaviour change interventions to reduce population salt intake.

PubMed

Trieu, Kathy; McMahon, Emma; Santos, Joseph Alvin; Bauman, Adrian; Jolly, Kellie-Ann; Bolam, Bruce; Webster, Jacqui

2017-02-08

Excess salt intake is a major cause of raised blood pressure-the leading risk factor for death and disability worldwide. Although behaviour change interventions such as awareness campaigns and health education programs are implemented to reduce salt intake, their effectiveness is unclear. This global systematic review investigates the impact of population-level behaviour change interventions that aim to reduce salt intake. A search for published and grey literature was conducted using PubMed, Cochrane Library, Embase, Web of Science, Sage, Scopus, OpenGrey, Google Scholar and other relevant organizations' websites. Studies were included if 1) published between 2005 and 2015; 2) the education or awareness-raising interventions were aimed at the population or sub-population and 3) salt intake and/or salt-related behaviours were outcome measures. Study and intervention characteristics were extracted for the descriptive synthesis and study quality was assessed. Twenty two studies involving 41,448 participants were included. Most were conducted in high income countries (n = 16), targeting adults (n = 21) in the general population (n = 16). Behaviour change interventions were categorised as health education interventions (n = 14), public awareness campaigns (n = 4) and multi-component interventions (including both health education and awareness campaigns, n = 4). 19 of the 22 studies demonstrated significant reductions in estimated salt intake and/or improvement in salt-related behaviours. All studies showed high risk of bias in one or more domains. Of the 10 higher quality studies, 5 found a significant effect on salt intake or salt behaviours based on the more objective outcome assessment method. Based on moderate quality of evidence, population-level behaviour change interventions can improve salt-related behaviours and/or reduce salt intake. However, closer analysis of higher quality studies show inconsistent evidence of the effectiveness and limited effect sizes suggest the implementation of education and awareness-raising interventions alone are unlikely to be adequate in reducing population salt intake to the recommended levels. A framework which guides rigorous research and evaluation of population-level interventions in real-world settings would help understand and support more effective implementation of interventions to reduce salt intake.

Sex change and effective population size: implications for population genetic studies in marine fish.

PubMed

Coscia, I; Chopelet, J; Waples, R S; Mann, B Q; Mariani, S

2016-10-01

Large variance in reproductive success is the primary factor that reduces effective population size (Ne) in natural populations. In sequentially hermaphroditic (sex-changing) fish, the sex ratio is typically skewed and biased towards the 'first' sex, while reproductive success increases considerably after sex change. Therefore, sex-changing fish populations are theoretically expected to have lower Ne than gonochorists (separate sexes), assuming all other parameters are essentially equal. In this study, we estimate Ne from genetic data collected from two ecologically similar species living along the eastern coast of South Africa: one gonochoristic, the 'santer' sea bream Cheimerius nufar, and one protogynous (female-first) sex changer, the 'slinger' sea bream Chrysoblephus puniceus. For both species, no evidence of genetic structuring, nor significant variation in genetic diversity, was found in the study area. Estimates of contemporary Ne were significantly lower in the protogynous species, but the same pattern was not apparent over historical timescales. Overall, our results show that sequential hermaphroditism may affect Ne differently over varying time frames, and that demographic signatures inferred from genetic markers with different inheritance modes also need to be interpreted cautiously, in relation to sex-changing life histories.

Projected effects of climate and development on California wildfire emissions through 2100.

PubMed

Hurteau, Matthew D; Westerling, Anthony L; Wiedinmyer, Christine; Bryant, Benjamin P

2014-02-18

Changing climatic conditions are influencing large wildfire frequency, a globally widespread disturbance that affects both human and natural systems. Understanding how climate change, population growth, and development patterns will affect the area burned by and emissions from wildfires and how populations will in turn be exposed to emissions is critical for climate change adaptation and mitigation planning. We quantified the effects of a range of population growth and development patterns in California on emission projections from large wildfires under six future climate scenarios. Here we show that end-of-century wildfire emissions are projected to increase by 19-101% (median increase 56%) above the baseline period (1961-1990) in California for a medium-high temperature scenario, with the largest emissions increases concentrated in northern California. In contrast to other measures of wildfire impacts previously studied (e.g., structural loss), projected population growth and development patterns are unlikely to substantially influence the amount of projected statewide wildfire emissions. However, increases in wildfire emissions due to climate change may have detrimental impacts on air quality and, combined with a growing population, may result in increased population exposure to unhealthy air pollutants.

Comparing Climate Change and Species Invasions as Drivers of Coldwater Fish Population Extirpations

PubMed Central

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

2011-01-01

Species are influenced by multiple environmental stressors acting simultaneously. Our objective was to compare the expected effects of climate change and invasion of non-indigenous rainbow smelt (Osmerus mordax) on cisco (Coregonus artedii) population extirpations at a regional level. We assembled a database of over 13,000 lakes in Wisconsin, USA, summarising fish occurrence, lake morphology, water chemistry, and climate. We used A1, A2, and B1 scenarios from the Intergovernmental Panel on Climate Change (IPCC) of future temperature conditions for 15 general circulation models in 2046–2065 and 2081–2100 totalling 78 projections. Logistic regression indicated that cisco tended to occur in cooler, larger, and deeper lakes. Depending upon the amount of warming, 25–70% of cisco populations are predicted to be extirpated by 2100. In addition, cisco are influenced by the invasion of rainbow smelt, which prey on young cisco. Projecting current estimates of rainbow smelt spread and impact into the future will result in the extirpation of about 1% of cisco populations by 2100 in Wisconsin. Overall, the effect of climate change is expected to overshadow that of species invasion as a driver of coldwater fish population extirpations. Our results highlight the potentially dominant role of climate change as a driver of biotic change. PMID:21860661

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

PubMed

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

2011-01-01

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

Predicting extinction risks under climate change: coupling stochastic population models with dynamic bioclimatic habitat models.

PubMed

Keith, David A; Akçakaya, H Resit; Thuiller, Wilfried; Midgley, Guy F; Pearson, Richard G; Phillips, Steven J; Regan, Helen M; Araújo, Miguel B; Rebelo, Tony G

2008-10-23

Species responses to climate change may be influenced by changes in available habitat, as well as population processes, species interactions and interactions between demographic and landscape dynamics. Current methods for assessing these responses fail to provide an integrated view of these influences because they deal with habitat change or population dynamics, but rarely both. In this study, we linked a time series of habitat suitability models with spatially explicit stochastic population models to explore factors that influence the viability of plant species populations under stable and changing climate scenarios in South African fynbos, a global biodiversity hot spot. Results indicate that complex interactions between life history, disturbance regime and distribution pattern mediate species extinction risks under climate change. Our novel mechanistic approach allows more complete and direct appraisal of future biotic responses than do static bioclimatic habitat modelling approaches, and will ultimately support development of more effective conservation strategies to mitigate biodiversity losses due to climate change.

Projected response of an endangered marine turtle population to climate change

NASA Astrophysics Data System (ADS)

Saba, Vincent S.; Stock, Charles A.; Spotila, James R.; Paladino, Frank V.; Tomillo, Pilar Santidrián

2012-11-01

Assessing the potential impacts of climate change on individual species and populations is essential for the stewardship of ecosystems and biodiversity. Critically endangered leatherback turtles in the eastern Pacific Ocean are excellent candidates for such an assessment because their sensitivity to contemporary climate variability has been substantially studied. If incidental fisheries mortality is eliminated, this population still faces the challenge of recovery in a rapidly changing climate. Here we combined an Earth system model, climate model projections assessed by the Intergovernmental Panel on Climate Change and a population dynamics model to estimate a 7% per decade decline in the Costa Rica nesting population over the twenty-first century. Whereas changes in ocean conditions had a small effect on the population, the ~2.5°C warming of the nesting beach was the primary driver of the decline through reduced hatching success and hatchling emergence rate. Hatchling sex ratio did not substantially change. Adjusting nesting phenology or changing nesting sites may not entirely prevent the decline, but could offset the decline rate. However, if future observations show a long-term decline in hatching success and emergence rate, anthropogenic climate mitigation of nests (for example, shading, irrigation) may be able to preserve the nesting population.

Gender effect on public stigma changes towards psychosis in the Hong Kong Chinese population: a comparison between population surveys of 2009 and 2014.

PubMed

Chan, S K W; Lee, K W; Hui, C L M; Chang, W C; Lee, E H M; Chen, E Y H

2017-03-01

Public stigma is an important barrier to the recovery of patients with psychosis. The current study aimed to investigate the change in stigma towards psychosis and knowledge about psychosis between 2009 and 2014 among the Chinese population in Hong Kong, with a specific focus on gender role. Random telephone survey of general population in Hong Kong was conducted in 2009 and 2014. Stigma was measured with the revised Link's Perceived Discrimination-Devaluation Scale (LPDDS). Logistic regression was used to explore the effect of time on the change of knowledge of psychosis, and linear regression was used to explore the effect of time on the change of stigma. Change of knowledge and stigma based on gender was specifically explored. In total, 1016 and 1018 subjects completed the survey in 2009 and 2014, respectively. Significantly, more people agreed with medication treatment for psychosis and fewer people had misunderstanding about psychosis. However, there was no significant change in stigma levels. Males were found to have a significant deterioration of stigma (B = 0.099, SE = 0.033, β = 0.100, p = 0.003) but not females. Significantly, more males endorsed medication treatment for psychosis (χ 2  = 5.850, df = 1, p = 0.016) but no change for females (χ 2  = 1.401, df = 1, p = 0.238). Results of this study suggested that there was an improvement in the biological understanding of psychosis but no change of public stigma within the Hong Kong Chinese population. The specific role of gender in relation to stigma and level of knowledge about psychosis indicates that this should be a consideration in designing future anti-stigma campaigns.

Climate Change Effects on Respiratory Health: Implications for Nursing.

PubMed

George, Maureen; Bruzzese, Jean-Marie; Matura, Lea Ann

2017-11-01

Greenhouse gases are driving climate change. This article explores the adverse health effects of climate change on a particularly vulnerable population: children and adults with respiratory conditions. This review provides a general overview of the effects of increasing temperatures, extreme weather, desertification, and flooding on asthma, chronic obstructive lung disease, and respiratory infections. We offer suggestions for future research to better understand climate change hazards, policies to support prevention and mitigation efforts targeting climate change, and clinical actions to reduce individual risk. Climate change produces a number of changes to the natural and built environments that may potentially increase respiratory disease prevalence, morbidity, and mortality. Nurses might consider focusing their research efforts on reducing the effects of greenhouse gases and in directing policy to mitigate the harmful effects of climate change. Nurses can also continue to direct educational and clinical actions to reduce risks for all populations, but most importantly, for our most vulnerable groups. While advancements have been made in understanding the impact of climate change on respiratory health, nurses can play an important role in reducing the deleterious effects of climate change. This will require a multipronged approach of research, policy, and clinical action. © 2017 Sigma Theta Tau International.

Archived DNA reveals fisheries and climate induced collapse of a major fishery.

PubMed

Bonanomi, Sara; Pellissier, Loïc; Therkildsen, Nina Overgaard; Hedeholm, Rasmus Berg; Retzel, Anja; Meldrup, Dorte; Olsen, Steffen Malskær; Nielsen, Anders; Pampoulie, Christophe; Hemmer-Hansen, Jakob; Wisz, Mary Susanne; Grønkjær, Peter; Nielsen, Einar Eg

2015-10-22

Fishing and climate change impact the demography of marine fishes, but it is generally ignored that many species are made up of genetically distinct locally adapted populations that may show idiosyncratic responses to environmental and anthropogenic pressures. Here, we track 80 years of Atlantic cod (Gadus morhua) population dynamics in West Greenland using DNA from archived otoliths in combination with fish population and niche based modeling. We document how the interacting effects of climate change and high fishing pressure lead to dramatic spatiotemporal changes in the proportions and abundance of different genetic populations, and eventually drove the cod fishery to a collapse in the early 1970s. Our results highlight the relevance of fisheries management at the level of genetic populations under future scenarios of climate change.

Archived DNA reveals fisheries and climate induced collapse of a major fishery

PubMed Central

Bonanomi, Sara; Pellissier, Loïc; Therkildsen, Nina Overgaard; Hedeholm, Rasmus Berg; Retzel, Anja; Meldrup, Dorte; Olsen, Steffen Malskær; Nielsen, Anders; Pampoulie, Christophe; Hemmer-Hansen, Jakob; Wisz, Mary Susanne; Grønkjær, Peter; Nielsen, Einar Eg

2015-01-01

Fishing and climate change impact the demography of marine fishes, but it is generally ignored that many species are made up of genetically distinct locally adapted populations that may show idiosyncratic responses to environmental and anthropogenic pressures. Here, we track 80 years of Atlantic cod (Gadus morhua) population dynamics in West Greenland using DNA from archived otoliths in combination with fish population and niche based modeling. We document how the interacting effects of climate change and high fishing pressure lead to dramatic spatiotemporal changes in the proportions and abundance of different genetic populations, and eventually drove the cod fishery to a collapse in the early 1970s. Our results highlight the relevance of fisheries management at the level of genetic populations under future scenarios of climate change. PMID:26489934

Archived DNA reveals fisheries and climate induced collapse of a major fishery

NASA Astrophysics Data System (ADS)

Bonanomi, Sara; Pellissier, Loïc; Therkildsen, Nina Overgaard; Hedeholm, Rasmus Berg; Retzel, Anja; Meldrup, Dorte; Olsen, Steffen Malskær; Nielsen, Anders; Pampoulie, Christophe; Hemmer-Hansen, Jakob; Wisz, Mary Susanne; Grønkjær, Peter; Nielsen, Einar Eg

2015-10-01

Fishing and climate change impact the demography of marine fishes, but it is generally ignored that many species are made up of genetically distinct locally adapted populations that may show idiosyncratic responses to environmental and anthropogenic pressures. Here, we track 80 years of Atlantic cod (Gadus morhua) population dynamics in West Greenland using DNA from archived otoliths in combination with fish population and niche based modeling. We document how the interacting effects of climate change and high fishing pressure lead to dramatic spatiotemporal changes in the proportions and abundance of different genetic populations, and eventually drove the cod fishery to a collapse in the early 1970s. Our results highlight the relevance of fisheries management at the level of genetic populations under future scenarios of climate change.

Climate Change and Its Impact on the Incarcerated Population: A Descriptive Review.

PubMed

Motanya, Njideka C; Valera, Pamela

2016-01-01

This descriptive review article describes climate change and its detrimental effects on incarcerated populations. Case examples are provided of specific natural disasters and deaths due to overheating temperatures. Because public health and social work aims to improve the health and social welfare of vulnerable populations, the authors explain why climate change should be considered a priority area in both fields. Examples are provided on how to improve conditions for the 2.4 million men, women, and youth who are incarcerated.

Endogenous technological and demographic change under increasing water scarcity

NASA Astrophysics Data System (ADS)

Pande, Saket; Ertsen, Maurits; Sivapalan, Murugesu

2014-05-01

The ancient civilization in the Indus Valley civilization dispersed under extreme dry conditions; there are indications that the same holds for many other ancient societies. Even contemporary societies, such as the one in Murrumbidgee river basin in Australia, have started to witness a decline in overall population under increasing water scarcity. Hydroclimatic change may not be the sole predictor of the fate of contemporary societies in water scarce regions and many critics of such (perceived) hydroclimatic determinism have suggested that technological change may ameliorate the effects of increasing water scarcity and as such counter the effects of hydroclimatic changes. To study the role of technological change on the dynamics of coupled human-water systems, we develop a simple overlapping-generations model of endogenous technological and demographic change. We model technological change as an endogenous process that depends on factors such as the investments that are (endogenously) made in a society, the (endogenous) diversification of a society into skilled and unskilled workers, a society's patience in terms of its present consumption vs. future consumption, production technology and the (endogenous) interaction of all of these factors. In the model the population growth rate is programmed to decline once consumption per capita crosses a "survival" threshold. This means we do not treat technology as an exogenous random sequence of events, but instead assume that it results (endogenously) from societal actions. The model demonstrates that technological change may indeed ameliorate the effects of increasing water scarcity but typically it does so only to a certain extent. It is possible that technological change may allow a society to escape the effect of increasing water scarcity, leading to a (super)-exponential rise in technology and population. However, such cases require the rate of success of investment in technological advancement to be high. In other more realistic cases of technological success, we find that endogenous technology change only helps to delay the peak of population size before it inevitably starts to decline. While the model is a rather simple model of societal development, it is shown to be capable of replicating patterns of technological and population changes. It is capable of replicating the pattern of declining consumption per capita in presence of growth in aggregate production. It is also capable of replicating an exponential population rise, even under increasing water scarcity. The results of the model suggest that societies that declined or are declining in the face of extreme water scarcity may have done so due to slower rate of success of investment in technological advancement. The model suggests that the population decline occurs after a prolonged decline in consumption per capita, which in turn is due to the joint effect of initially increasing population and increasing water scarcity. This is despite technological advancement and increase in aggregate production. We suggest that declining consumption per capita despite technological advancement and increase in aggregate production may serve as a useful predictor of upcoming decline in contemporary societies in water scarce basins.

Projection of future temperature-related mortality due to climate and demographic changes.

PubMed

Lee, Jae Young; Kim, Ho

2016-09-01

Understanding the effects of global climate change from both environmental and human health perspectives has gained great importance. Particularly, studies on the direct effect of temperature increase on future mortality have been conducted. However, few of those studies considered population changes, and although the world population is rapidly aging, no previous study considered the effect of society aging. Here we present a projection of future temperature-related mortality due to both climate and demographic changes in seven major cities of South Korea, a fast aging country, until 2100; we used the HadGEM3-RA model under four Representative Concentration Pathway (RCP) scenarios (RCP 2.6, 4.5, 6.0, and 8.5) and the United Nations world population prospects under three fertility scenarios (high, medium, and low). The results showed markedly increased mortality in the elderly group, significantly increasing the overall future mortality. In 2090s, South Korea could experience a four- to six-time increase in temperature-related mortality compared to that during 1992-2010 under four different RCP scenarios and three different fertility variants, while the mortality is estimated to increase only by 0.5 to 1.5 times assuming no population aging. Therefore, not considering population aging may significantly underestimate temperature risks. Copyright © 2016 Elsevier Ltd. All rights reserved.

More rapid climate change promotes evolutionary rescue through selection for increased dispersal distance.

PubMed

Boeye, Jeroen; Travis, Justin M J; Stoks, Robby; Bonte, Dries

2013-02-01

Species can either adapt to new conditions induced by climate change or shift their range in an attempt to track optimal environmental conditions. During current range shifts, species are simultaneously confronted with a second major anthropogenic disturbance, landscape fragmentation. Using individual-based models with a shifting climate window, we examine the effect of different rates of climate change on the evolution of dispersal distances through changes in the genetically determined dispersal kernel. Our results demonstrate that the rate of climate change is positively correlated to the evolved dispersal distances although too fast climate change causes the population to crash. When faced with realistic rates of climate change, greater dispersal distances evolve than those required for the population to keep track of the climate, thereby maximizing population size. Importantly, the greater dispersal distances that evolve when climate change is more rapid, induce evolutionary rescue by facilitating the population in crossing large gaps in the landscape. This could ensure population persistence in case of range shifting in fragmented landscapes. Furthermore, we highlight problems in using invasion speed as a proxy for potential range shifting abilities under climate change.

A hierarchical model for regional analysis of population change using Christmas Bird Count data, with application to the American Black Duck

USGS Publications Warehouse

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.

Contrasting effects of climate change on rabbit populations through reproduction.

PubMed

Tablado, Zulima; Revilla, Eloy

2012-01-01

Climate change is affecting many physical and biological processes worldwide. Anticipating its effects at the level of populations and species is imperative, especially for organisms of conservation or management concern. Previous studies have focused on estimating future species distributions and extinction probabilities directly from current climatic conditions within their geographical ranges. However, relationships between climate and population parameters may be so complex that to make these high-level predictions we need first to understand the underlying biological processes driving population size, as well as their individual response to climatic alterations. Therefore, the objective of this study is to investigate the influence that climate change may have on species population dynamics through altering breeding season. We used a mechanistic model based on drivers of rabbit reproductive physiology together with demographic simulations to show how future climate-driven changes in breeding season result in contrasting rabbit population trends across Europe. In the Iberian Peninsula, where rabbits are a native species of high ecological and economic value, breeding seasons will shorten and become more variable leading to population declines, higher extinction risk, and lower resilience to perturbations. Whereas towards north-eastern countries, rabbit numbers are expected to increase through longer and more stable reproductive periods, which augment the probability of new rabbit invasions in those areas. Our study reveals the type of mechanisms through which climate will cause alterations at the species level and emphasizes the need to focus on them in order to better foresee large-scale complex population trends. This is especially important in species like the European rabbit whose future responses may aggravate even further its dual keystone/pest problematic. Moreover, this approach allows us to predict not only distribution shifts but also future population status and growth, and to identify the demographic parameters on which to focus to mitigate global change effects.

Contrasting Effects of Climate Change on Rabbit Populations through Reproduction

PubMed Central

Tablado, Zulima; Revilla, Eloy

2012-01-01

Background Climate change is affecting many physical and biological processes worldwide. Anticipating its effects at the level of populations and species is imperative, especially for organisms of conservation or management concern. Previous studies have focused on estimating future species distributions and extinction probabilities directly from current climatic conditions within their geographical ranges. However, relationships between climate and population parameters may be so complex that to make these high-level predictions we need first to understand the underlying biological processes driving population size, as well as their individual response to climatic alterations. Therefore, the objective of this study is to investigate the influence that climate change may have on species population dynamics through altering breeding season. Methodology/Principal Findings We used a mechanistic model based on drivers of rabbit reproductive physiology together with demographic simulations to show how future climate-driven changes in breeding season result in contrasting rabbit population trends across Europe. In the Iberian Peninsula, where rabbits are a native species of high ecological and economic value, breeding seasons will shorten and become more variable leading to population declines, higher extinction risk, and lower resilience to perturbations. Whereas towards north-eastern countries, rabbit numbers are expected to increase through longer and more stable reproductive periods, which augment the probability of new rabbit invasions in those areas. Conclusions/Significance Our study reveals the type of mechanisms through which climate will cause alterations at the species level and emphasizes the need to focus on them in order to better foresee large-scale complex population trends. This is especially important in species like the European rabbit whose future responses may aggravate even further its dual keystone/pest problematic. Moreover, this approach allows us to predict not only distribution shifts but also future population status and growth, and to identify the demographic parameters on which to focus to mitigate global change effects. PMID:23152836

The relative importance of intrinsic and extrinsic drivers to population growth vary among local populations of Greater Sage-Grouse: An integrated population modeling approach

USGS Publications Warehouse

Coates, Peter S.; Prochazka, Brian G.; Ricca, Mark A.; Halstead, Brian J.; Casazza, Michael L.; Blomberg, Erik J.; Brussee, Brianne E.; Wiechman, Lief; Tebbenkamp, Joel; Gardner, Scott C.; Reese, Kerry P.

2018-01-01

Consideration of ecological scale is fundamental to understanding and managing avian population growth and decline. Empirically driven models for population dynamics and demographic processes across multiple spatial scales can be powerful tools to help guide conservation actions. Integrated population models (IPMs) provide a framework for better parameter estimation by unifying multiple sources of data (e.g., count and demographic data). Hierarchical structure within such models that include random effects allow for varying degrees of data sharing across different spatiotemporal scales. We developed an IPM to investigate Greater Sage-Grouse (Centrocercus urophasianus) on the border of California and Nevada, known as the Bi-State Distinct Population Segment. Our analysis integrated 13 years of lek count data (n > 2,000) and intensive telemetry (VHF and GPS; n > 350 individuals) data across 6 subpopulations. Specifically, we identified the most parsimonious models among varying random effects and density-dependent terms for each population vital rate (e.g., nest survival). Using a joint likelihood process, we integrated the lek count data with the demographic models to estimate apparent abundance and refine vital rate parameter estimates. To investigate effects of climatic conditions, we extended the model to fit a precipitation covariate for instantaneous rate of change (r). At a metapopulation extent (i.e. Bi-State), annual population rate of change λ (er) did not favor an overall increasing or decreasing trend through the time series. However, annual changes in λ were driven by changes in precipitation (one-year lag effect). At subpopulation extents, we identified substantial variation in λ and demographic rates. One subpopulation clearly decoupled from the trend at the metapopulation extent and exhibited relatively high risk of extinction as a result of low egg fertility. These findings can inform localized, targeted management actions for specific areas, and status of the species for the larger Bi-State.

Promoting walking and cycling as an alternative to using cars: systematic review

PubMed Central

Ogilvie, David; Egan, Matt; Hamilton, Val; Petticrew, Mark

2004-01-01

Objectives To assess what interventions are effective in promoting a population shift from using cars towards walking and cycling and to assess the health effects of such interventions. Data sources Published and unpublished reports in any language identified from electronic databases, bibliographies, websites, and reference lists. Review methods Systematic search and appraisal to identify experimental or observational studies with a prospective or controlled retrospective design that evaluated any intervention applied to an urban population or area by measuring outcomes in members of the local population. Results 22 studies met the inclusion criteria. We found some evidence that targeted behaviour change programmes can change the behaviour of motivated subgroups, resulting (in the largest study) in a shift of around 5% of all trips at a population level. Single studies of commuter subsidies and a new railway station also showed positive effects. The balance of best available evidence about publicity campaigns, engineering measures, and other interventions suggests that they have not been effective. Participants in trials of active commuting experienced short term improvements in certain measures of health and fitness, but we found no good evidence on effects on health of any effective intervention at population level. Conclusions The best available evidence of effectiveness in promoting a modal shift is for targeted behaviour change programmes, but the social distribution of their effects is unclear and some other types of intervention have yet to be rigorously evaluated. PMID:15385407

Environmental change disrupts communication and sexual selection in a stickleback population.

PubMed

Candolin, Ulrika; Tukiainen, Iina; Bertell, Elina

2016-04-01

Environmental change that disrupts communication during mate choice and alters sexual selection could influence population dynamics. Yet little is known about such long-term effects. We investigated experimentally the consequences that disrupted visual communication during mate choice has for the quantity and viability of offspring produced in a threespine stickleback population (Gasterosteus aculeatus). We further related the results to long-term monitoring of population dynamics in the field to determine if changes are apparent under natural conditions. The results show that impaired visual communication because of algal blooms reduces reliability of male visual signals as indicators of offspring survival during their first weeks of life. This relaxes sexual selection but has no effect on the number of offspring hatching, as most males have a high hatching success in turbid water. Despite eutrophication and high turbidity levels that interfere with communication during mate choice, the population has grown during recent decades. Large numbers of offspring hatching, combined with high variation in juvenile fitness, has probably shifted selection to later life history stages and maintained a viable population. Together with reduced cost of sexual selection and ongoing ecosystem changes caused by human activities, this could have promoted population growth. These results point to the complexity of ecosystems and the necessity to consider all influencing factors when attempting to understand impacts of human activities on populations.

Predicting responses to climate change requires all life-history stages.

PubMed

Zeigler, Sara

2013-01-01

In Focus: Radchuk, V., Turlure, C. & Schtickzelle, N. (2013) Each life stage matters: the importance of assessing response to climate change over the complete life cycle in butterflies. Journal of Animal Ecology, 82, 275-285. Population-level responses to climate change depend on many factors, including unexpected interactions among life history attributes; however, few studies examine climate change impacts over complete life cycles of focal species. Radchuk, Turlure & Schtickzelle () used experimental and modelling approaches to predict population dynamics for the bog fritillary butterfly under warming scenarios. Although they found that warming improved fertility and survival of all stages with one exception, populations were predicted to decline because overwintering larvae, whose survival declined with warming, were disproportionately important contributors to population growth. This underscores the importance of considering all life history stages in analyses of climate change's effects on population dynamics. © 2012 The Authors. Journal of Animal Ecology © 2012 British Ecological Society.

Effects of multiple stresses hydropower, acid deposition and climate change on water chemistry and salmon populations in the River Otra, Norway.

PubMed

Wright, Richard F; Couture, Raoul-Marie; Christiansen, Anne B; Guerrero, José-Luis; Kaste, Øyvind; Barlaup, Bjørn T

2017-01-01

Many surface waters in Europe suffer from the adverse effects of multiple stresses. The Otra River, southernmost Norway, is impacted by acid deposition, hydropower development and increasingly by climate change. The river holds a unique population of land-locked salmon and anadromous salmon in the lower reaches. Both populations have been severely affected by acidification. The decrease in acid deposition since the 1980s has led to partial recovery of both populations. Climate change with higher temperatures and altered precipitation can potentially further impact fish populations. We used a linked set of process-oriented models to simulate future climate, discharge, and water chemistry at five sub-catchments in the Otra river basin. Projections to year 2100 indicate that future climate change will give a small but measureable improvement in water quality, but that additional reductions in acid deposition are needed to promote full restoration of the fish communities. These results can help guide management decisions to sustain key salmon habitats and carry out effective long-term mitigation strategies such as liming. The Otra River is typical of many rivers in Europe in that it fails to achieve the good ecological status target of the EU Water Framework Directive. The programme of measures needed in the river basin management plan necessarily must consider the multiple stressors of acid deposition, hydropower, and climate change. This is difficult, however, as the synergistic and antagonistic effects are complex and challenging to address with modelling tools currently available. Copyright © 2016 Elsevier B.V. All rights reserved.

The Roles of Dispersal, Fecundity, and Predation in the Population Persistence of an Oak (Quercus engelmannii) under Global Change

PubMed Central

Conlisk, Erin; Lawson, Dawn; Syphard, Alexandra D.; Franklin, Janet; Flint, Lorraine; Flint, Alan; Regan, Helen M.

2012-01-01

A species’ response to climate change depends on the interaction of biotic and abiotic factors that define future habitat suitability and species’ ability to migrate or adapt. The interactive effects of processes such as fire, dispersal, and predation have not been thoroughly addressed in the climate change literature. Our objective was to examine how life history traits, short-term global change perturbations, and long-term climate change interact to affect the likely persistence of an oak species - Quercus engelmannii (Engelmann oak). Specifically, we combined dynamic species distribution models, which predict suitable habitat, with stochastic, stage-based metapopulation models, which project population trajectories, to evaluate the effects of three global change factors – climate change, land use change, and altered fire frequency – emphasizing the roles of dispersal and seed predation. Our model predicted dramatic reduction in Q. engelmannii abundance, especially under drier climates and increased fire frequency. When masting lowers seed predation rates, decreased masting frequency leads to large abundance decreases. Current rates of dispersal are not likely to prevent these effects, although increased dispersal could mitigate population declines. The results suggest that habitat suitability predictions by themselves may under-estimate the impact of climate change for other species and locations. PMID:22623955

Range position and climate sensitivity: The structure of among-population demographic responses to climatic variation

USGS Publications Warehouse

Amburgey, Staci M.; Miller, David A. W.; Grant, Evan H. Campbell; Rittenhouse, Tracy A. G.; Benard, Michael F.; Richardson, Jonathan L.; Urban, Mark C.; Hughson, Ward; Brand, Adrianne B,; Davis, Christopher J.; Hardin, Carmen R.; Paton, Peter W. C.; Raithel, Christopher J.; Relyea, Rick A.; Scott, A. Floyd; Skelly, David K.; Skidds, Dennis E.; Smith, Charles K.; Werner, Earl E.

2018-01-01

Species’ distributions will respond to climate change based on the relationship between local demographic processes and climate and how this relationship varies based on range position. A rarely tested demographic prediction is that populations at the extremes of a species’ climate envelope (e.g., populations in areas with the highest mean annual temperature) will be most sensitive to local shifts in climate (i.e., warming). We tested this prediction using a dynamic species distribution model linking demographic rates to variation in temperature and precipitation for wood frogs (Lithobates sylvaticus) in North America. Using long-term monitoring data from 746 populations in 27 study areas, we determined how climatic variation affected population growth rates and how these relationships varied with respect to long-term climate. Some models supported the predicted pattern, with negative effects of extreme summer temperatures in hotter areas and positive effects on recruitment for summer water availability in drier areas. We also found evidence of interacting temperature and precipitation influencing population size, such as extreme heat having less of a negative effect in wetter areas. Other results were contrary to predictions, such as positive effects of summer water availability in wetter parts of the range and positive responses to winter warming especially in milder areas. In general, we found wood frogs were more sensitive to changes in temperature or temperature interacting with precipitation than to changes in precipitation alone. Our results suggest that sensitivity to changes in climate cannot be predicted simply by knowing locations within the species’ climate envelope. Many climate processes did not affect population growth rates in the predicted direction based on range position. Processes such as species-interactions, local adaptation, and interactions with the physical landscape likely affect the responses we observed. Our work highlights the need to measure demographic responses to changing climate.

Detecting population recovery using gametic disequilibrium-based effective population size estimates

Treesearch

David A. Tallmon; Robin S. Waples; Dave Gregovich; Michael K. Schwartz

2012-01-01

Recovering populations often must meet specific growth rate or abundance targets before their legal status can be changed from endangered or threatened. While the efficacy, power, and performance of population metrics to infer trends in declining populations has received considerable attention, how these same metrics perform when populations are increasing is less...

Variation in sensitivity of large benthic Foraminifera to the combined effects of ocean warming and local impacts.

PubMed

Prazeres, Martina; Roberts, T Edward; Pandolfi, John M

2017-03-23

Large benthic foraminifera (LBF) are crucial marine calcifiers in coral reefs, and sensitive to environmental changes. Yet, many species successfully colonise a wide range of habitats including highly fluctuating environments. We tested the combined effects of ocean warming, local impacts and different light levels on populations of the common LBF Amphistegina lobifera collected along a cross-shelf gradient of temperature and nutrients fluctuations. We analysed survivorship, bleaching frequency, chlorophyll a content and fecundity. Elevated temperature and nitrate significantly reduced survivorship and fecundity of A. lobifera across populations studied. This pattern was exacerbated when combined with below optimum light levels. Inshore populations showed a consistent resistance to increased temperature and nitrate levels, but all populations studied were significantly affected by light reduction. These findings demonstrated the capacity of some populations of LBF to acclimate to local conditions; nonetheless improvements in local water quality can ultimately ameliorate effects of climate change in local LBF populations.

Effects of urban land-use change on biogeochemical cycles

Treesearch

Richard V. Pouyat; Diane E. Pataki; Kenneth T. Belt; Peter M. Groffman; John Hom; Lawrence E. Band

2007-01-01

Urban land-use change, the conversion of agricultural recand natural ecosystems to human settlements, has become an important component of global change. Virtually all of the projected increase in the world's population is expected to occur in cities so that by the year 2007 more than half of the global population is expected to live in urban areas (United Nations...

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

PubMed

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

2009-02-10

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

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

PubMed Central

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

2009-01-01

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

A multi-model framework for simulating wildlife population response to land-use and climate change

USGS Publications Warehouse

McRae, B.H.; Schumaker, N.H.; McKane, R.B.; Busing, R.T.; Solomon, A.M.; Burdick, C.A.

2008-01-01

Reliable assessments of how human activities will affect wildlife populations are essential for making scientifically defensible resource management decisions. A principle challenge of predicting effects of proposed management, development, or conservation actions is the need to incorporate multiple biotic and abiotic factors, including land-use and climate change, that interact to affect wildlife habitat and populations through time. Here we demonstrate how models of land-use, climate change, and other dynamic factors can be integrated into a coherent framework for predicting wildlife population trends. Our framework starts with land-use and climate change models developed for a region of interest. Vegetation changes through time under alternative future scenarios are predicted using an individual-based plant community model. These predictions are combined with spatially explicit animal habitat models to map changes in the distribution and quality of wildlife habitat expected under the various scenarios. Animal population responses to habitat changes and other factors are then projected using a flexible, individual-based animal population model. As an example application, we simulated animal population trends under three future land-use scenarios and four climate change scenarios in the Cascade Range of western Oregon. We chose two birds with contrasting habitat preferences for our simulations: winter wrens (Troglodytes troglodytes), which are most abundant in mature conifer forests, and song sparrows (Melospiza melodia), which prefer more open, shrubby habitats. We used climate and land-use predictions from previously published studies, as well as previously published predictions of vegetation responses using FORCLIM, an individual-based forest dynamics simulator. Vegetation predictions were integrated with other factors in PATCH, a spatially explicit, individual-based animal population simulator. Through incorporating effects of landscape history and limited dispersal, our framework predicted population changes that typically exceeded those expected based on changes in mean habitat suitability alone. Although land-use had greater impacts on habitat quality than did climate change in our simulations, we found that small changes in vital rates resulting from climate change or other stressors can have large consequences for population trajectories. The ability to integrate bottom-up demographic processes like these with top-down constraints imposed by climate and land-use in a dynamic modeling environment is a key advantage of our approach. The resulting framework should allow researchers to synthesize existing empirical evidence, and to explore complex interactions that are difficult or impossible to capture through piecemeal modeling approaches. ?? 2008 Elsevier B.V.

Endogenous technological and demographic change under increasing water scarcity

NASA Astrophysics Data System (ADS)

Pande, S.; Ertsen, M.; Sivapalan, M.

2013-12-01

Many ancient civilizations such as the Indus Valley civilization dispersed under extreme dry conditions. Even contemporary societies such as the one in Murrumbidgee river basin, Australia, have started to witness a decline in overall population under increasing water scarcity. Skeptics of hydroclimatic determinism have often cautioned against the use of hydroclimatic change as the sole predictor of the fate of contemporary societies in water scarce regions by suggesting that technological change may ameliorate the effects of increasing water scarcity. We here develop a simple overlapping generations model of endogenous technological and demographic change. It models technological change not as an exogenous random sequence of events but as an endogenous process (as is widely accepted in contemporary literature) that depends on factors such as the investments that are (endogenously) made in a society, the endogenous diversification of a society into skilled and unskilled workers, individuals' patience in terms of its present consumption versus future consumption, the production technology and the (endogenous) interaction of these factors. The population growth rate is modeled to decline once consumption per capita crosses a ';survival' threshold. The model demonstrates that technological change may ameliorate the effects of increasing water scarcity but only to a certain extent in many cases. It is possible that technological change may allow a society to escape the effect of increasing water society, leading to an exponential rise in technology and population. However, such cases require that the rate of success of investment in technological advancement is high. In other more realistic cases of technological success, we find that endogenous technology change has an effect delaying the peak of population before it starts to decline. While the model is a rather simple model of societal growth, it is capable of replicating (not to scale) patterns of technological change (proxies of which in ancient technology include irrigation canals, metal tools, and the use of horses for labor while in contemporary societies its proxies may be the advent of drip irrigation, increasing reservoir storage capacity etc) and population change. It is capable of replicating the pattern of declining consumption per capita in presence of growth in aggregate production. It is also capable of modeling the exponential population rise even under increasing water scarcity. The results of the model suggest, as one of the many other possible explanations, that ancient societies that declined in the face of extreme water scarcity may have done so due to slower rate of success of investment in technological advancement. The model suggests that the population decline occurs after a prolonged decline in consumption per capita, which in turn is due to the joint effect of initially increasing population and increasing water scarcity. This is despite technological advancement and increase in aggregate production. Thus declining consumption per capita despite technological advancement and increase in aggregate production may serve as a useful predictor of upcoming decline in contemporary societies in water scarce basins.

Large-scale adaptive differentiation in the alpine perennial herb Arabis alpina.

PubMed

Toräng, Per; Wunder, Jörg; Obeso, José Ramón; Herzog, Michel; Coupland, George; Ågren, Jon

2015-04-01

Information about the incidence and magnitude of local adaptation can help to predict the response of natural populations to a changing environment, and should be of particular interest in arctic and alpine environments where the effects of climate change are expected to be severe. To quantify adaptive differentiation in the arctic-alpine perennial herb Arabis alpina, we conducted reciprocal transplant experiments for 3 yr between Spanish and Scandinavian populations. At the sites of one Spanish and one Scandinavian population, we planted seedlings representing two Spanish and four Scandinavian populations, and recorded survival, flowering propensity and fecundity. The experiment was replicated in two subsequent years. The results demonstrate strong adaptive differentiation between A. alpina populations from the two regions. At the field site in Spain, survival and fruit production of Spanish populations were higher than those of Scandinavian populations, while the opposite was true at the site in Scandinavia, and these differences were consistent across years. By comparison, fitness varied little among populations from the same region. The results suggest that the magnitude and geographical scale of local adaptation need to be considered in predictions of the effects of global change on the dynamics of arctic and alpine plant populations. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Potential effects of anthropogenic greenhouse gases on avian habitats and populations in the northern Great Plains

USGS Publications Warehouse

Larson, Diane L.

1994-01-01

Biotic response to the buildup of greenhouse gases in Earth's atmosphere is considerably more complex than an adjustment to changing temperature and precipitation. The fertilization effect carbon dioxide has on some plants, the impact UVB radiation has on health and productivity of organisms, and the resulting changes in competitive balance and trophic structure must also be considered. The intent of this paper is to review direct and indirect effects of anthropogenic greenhouse gases on wildlife, and to explore possible effects on populations of birds and their habitats in the northern Great Plains.Many of the potential effects of increasing greenhouse gases, such as declining plant nutritional value, changes in timing of insect emergence, and fewer and saltier wetlands, foreshadow a decline in avian populations on the Great Plains. However, other possible effects such as increased drought resistance and water use efficiency of vegetation, longer growing seasons, and greater overall plant biomass promise at least some mitigation. Effects of multiple simultaneous perturbations such as can be expected under doubled carbon dioxide scenarios will require substantial basic research to clarify.

RAPID EVOLUTION CAUSED BY POLLINATOR LOSS IN MIMULUS GUTTATUS

PubMed Central

Bodbyl Roels, Sarah A.; Kelly, John K.

2018-01-01

Anthropogenic perturbations including habitat loss and emerging disease are changing pollinator communities and generating novel selection pressures on plant populations. Disruption of plant–pollinator relationships is predicted to cause plant mating system evolution, although this process has not been directly observed. This study demonstrates the immediate evolutionary effects of pollinator loss within experimental populations of a predominately outcrossing wildflower. Initially equivalent populations evolved for five generations within two pollination treatments: abundant bumblebee pollinators versus no pollinators. The populations without pollinators suffered greatly reduced fitness in early generations but rebounded as they evolved an improved ability to self-fertilize. All populations diverged in floral, developmental, and life-history traits, but only a subset of characters showed clear association with pollination treatment. Pronounced treatment effects were noted for anther–stigma separation and autogamous seed set. Dramatic allele frequency changes at two chromosomal polymorphisms occurred in the no pollinator populations, explaining a large fraction of divergence in pollen viability. The pattern of phenotypic and genetic changes in this experiment favors a sequential model for the evolution of the multitrait “selfing syndrome” observed throughout angiosperms. PMID:21884055

Rapid evolution caused by pollinator loss in Mimulus guttatus.

PubMed

Roels, Sarah A Bodbyl; Kelly, John K

2011-09-01

Anthropogenic perturbations including habitat loss and emerging disease are changing pollinator communities and generating novel selection pressures on plant populations. Disruption of plant-pollinator relationships is predicted to cause plant mating system evolution, although this process has not been directly observed. This study demonstrates the immediate evolutionary effects of pollinator loss within experimental populations of a predominately outcrossing wildflower. Initially equivalent populations evolved for five generations within two pollination treatments: abundant bumblebee pollinators versus no pollinators. The populations without pollinators suffered greatly reduced fitness in early generations but rebounded as they evolved an improved ability to self-fertilize. All populations diverged in floral, developmental, and life-history traits, but only a subset of characters showed clear association with pollination treatment. Pronounced treatment effects were noted for anther-stigma separation and autogamous seed set. Dramatic allele frequency changes at two chromosomal polymorphisms occurred in the no pollinator populations, explaining a large fraction of divergence in pollen viability. The pattern of phenotypic and genetic changes in this experiment favors a sequential model for the evolution of the multitrait "selfing syndrome" observed throughout angiosperms. © 2011 The Author(s).

Effect of Premenstrual Mood Changes on the Couple Relationship.

ERIC Educational Resources Information Center

Atwood, Joan D.

1991-01-01

Investigated premenstrual mood changes in women and whether these mood changes have effects on interpersonal relationships. Analysis of responses from sample of 100 women from nonclinical college undergraduate and graduate psychology population found that 78.4 percent did experience mood changes prior to menstruation and 45 percent of these women…

Changes in seasonal climate outpace compensatory density-dependence in eastern brook trout

USGS Publications Warehouse

Bassar, Ronald D.; Letcher, Benjamin H.; Nislow, Keith H.; Whiteley, Andrew R.

2016-01-01

Understanding how multiple extrinsic (density-independent) factors and intrinsic (density-dependent) mechanisms influence population dynamics has become increasingly urgent in the face of rapidly changing climates. It is particularly unclear how multiple extrinsic factors with contrasting effects among seasons are related to declines in population numbers and changes in mean body size and whether there is a strong role for density-dependence. The primary goal of this study was to identify the roles of seasonal variation in climate driven environmental direct effects (mean stream flow and temperature) versus density-dependence on population size and mean body size in eastern brook trout (Salvelinus fontinalis). We use data from a 10-year capture-mark-recapture study of eastern brook trout in four streams in Western Massachusetts, USA to parameterize a discrete-time population projection model. The model integrates matrix modeling techniques used to characterize discrete population structures (age, habitat type and season) with integral projection models (IPMs) that characterize demographic rates as continuous functions of organismal traits (in this case body size). Using both stochastic and deterministic analyses we show that decreases in population size are due to changes in stream flow and temperature and that these changes are larger than what can be compensated for through density-dependent responses. We also show that the declines are due mostly to increasing mean stream temperatures decreasing the survival of the youngest age class. In contrast, increases in mean body size over the same period are the result of indirect changes in density with a lesser direct role of climate-driven environmental change.

Spatially Extensive Standardized Surveys Reveal Widespread, Multi-Decadal Increase in East Antarctic Adélie Penguin Populations.

PubMed

Southwell, Colin; Emmerson, Louise; McKinlay, John; Newbery, Kym; Takahashi, Akinori; Kato, Akiko; Barbraud, Christophe; DeLord, Karine; Weimerskirch, Henri

2015-01-01

Seabirds are considered to be useful and practical indicators of the state of marine ecosystems because they integrate across changes in the lower trophic levels and the physical environment. Signals from this key group of species can indicate broad scale impacts or response to environmental change. Recent studies of penguin populations, the most commonly abundant Antarctic seabirds in the west Antarctic Peninsula and western Ross Sea, have demonstrated that physical changes in Antarctic marine environments have profound effects on biota at high trophic levels. Large populations of the circumpolar-breeding Adélie penguin occur in East Antarctica, but direct, standardized population data across much of this vast coastline have been more limited than in other Antarctic regions. We combine extensive new population survey data, new population estimation methods, and re-interpreted historical survey data to assess decadal-scale change in East Antarctic Adélie penguin breeding populations. We show that, in contrast to the west Antarctic Peninsula and western Ross Sea where breeding populations have decreased or shown variable trends over the last 30 years, East Antarctic regional populations have almost doubled in abundance since the 1980's and have been increasing since the earliest counts in the 1960's. The population changes are associated with five-year lagged changes in the physical environment, suggesting that the changing environment impacts primarily on the pre-breeding age classes. East Antarctic marine ecosystems have been subject to a number of changes over the last 50 years which may have influenced Adélie penguin population growth, including decadal-scale climate variation, an inferred mid-20th century sea-ice contraction, and early-to-mid 20th century exploitation of fish and whale populations.

Spatially Extensive Standardized Surveys Reveal Widespread, Multi-Decadal Increase in East Antarctic Adélie Penguin Populations

PubMed Central

Southwell, Colin; Emmerson, Louise; McKinlay, John; Newbery, Kym; Takahashi, Akinori; Kato, Akiko; Barbraud, Christophe; DeLord, Karine; Weimerskirch, Henri

2015-01-01

Seabirds are considered to be useful and practical indicators of the state of marine ecosystems because they integrate across changes in the lower trophic levels and the physical environment. Signals from this key group of species can indicate broad scale impacts or response to environmental change. Recent studies of penguin populations, the most commonly abundant Antarctic seabirds in the west Antarctic Peninsula and western Ross Sea, have demonstrated that physical changes in Antarctic marine environments have profound effects on biota at high trophic levels. Large populations of the circumpolar-breeding Adélie penguin occur in East Antarctica, but direct, standardized population data across much of this vast coastline have been more limited than in other Antarctic regions. We combine extensive new population survey data, new population estimation methods, and re-interpreted historical survey data to assess decadal-scale change in East Antarctic Adélie penguin breeding populations. We show that, in contrast to the west Antarctic Peninsula and western Ross Sea where breeding populations have decreased or shown variable trends over the last 30 years, East Antarctic regional populations have almost doubled in abundance since the 1980’s and have been increasing since the earliest counts in the 1960’s. The population changes are associated with five-year lagged changes in the physical environment, suggesting that the changing environment impacts primarily on the pre-breeding age classes. East Antarctic marine ecosystems have been subject to a number of changes over the last 50 years which may have influenced Adélie penguin population growth, including decadal-scale climate variation, an inferred mid-20th century sea-ice contraction, and early-to-mid 20th century exploitation of fish and whale populations. PMID:26488299

Introgression Makes Waves in Inferred Histories of Effective Population Size.

PubMed

Hawks, John

2017-01-01

Human populations have a complex history of introgression and of changing population size. Human genetic variation has been affected by both these processes, so inference of past population size depends upon the pattern of gene flow and introgression among past populations. One remarkable aspect of human population history as inferred from genetics is a consistent "wave" of larger effective population sizes, found in both African and non-African populations, that appears to reflect events prior to the last 100,000 years. I carried out a series of simulations to investigate how introgression and gene flow from genetically divergent ancestral populations affect the inference of ancestral effective population size. Both introgression and gene flow from an extinct, genetically divergent population consistently produce a wave in the history of inferred effective population size. The time and amplitude of the wave reflect the time of origin of the genetically divergent ancestral populations and the strength of introgression or gene flow. These results demonstrate that even small fractions of introgression or gene flow from ancient populations may have visible effects on the inference of effective population size.

Applications of very high-resolution imagery in the study and conservation of large predators in the Southern Ocean.

PubMed

Larue, Michelle A; Knight, Joseph

2014-12-01

The Southern Ocean is one of the most rapidly changing ecosystems on the planet due to the effects of climate change and commercial fishing for ecologically important krill and fish. Because sea ice loss is expected to be accompanied by declines in krill and fish predators, decoupling the effects of climate and anthropogenic changes on these predator populations is crucial for ecosystem-based management of the Southern Ocean. We reviewed research published from 2007 to 2014 that incorporated very high-resolution satellite imagery to assess distribution, abundance, and effects of climate and other anthropogenic changes on populations of predators in polar regions. Very high-resolution imagery has been used to study 7 species of polar animals in 13 papers, many of which provide methods through which further research can be conducted. Use of very high-resolution imagery in the Southern Ocean can provide a broader understanding of climate and anthropogenic forces on populations and inform management and conservation recommendations. We recommend that conservation biologists continue to integrate high-resolution remote sensing into broad-scale biodiversity and population studies in remote areas, where it can provide much needed detail. © 2014 Society for Conservation Biology.

The consequences of poaching and anthropogenic change for forest elephants.

PubMed

Breuer, Thomas; Maisels, Fiona; Fishlock, Vicki

2016-10-01

Poaching has devastated forest elephant populations (Loxodonta cyclotis), and their habitat is dramatically changing. The long-term effects of poaching and other anthropogenic threats have been well studied in savannah elephants (Loxodonta africana), but the impacts of these changes for Central Africa's forest elephants have not been discussed. We examined potential repercussions of these threats and the related consequences for forest elephants in Central Africa by summarizing the lessons learned from savannah elephants and small forest elephant populations in West Africa. Forest elephant social organization is less known than the social organization of savannah elephants, but the close evolutionary history of these species suggests that they will respond to anthropogenic threats in broadly similar ways. The loss of older, experienced individuals in an elephant population disrupts ecological, social, and population parameters. Severe reduction of elephant abundance within Central Africa's forests can alter plant communities and ecosystem functions. Poaching, habitat alterations, and human population increase are probably compressing forest elephants into protected areas and increasing human-elephant conflict, which negatively affects their conservation. We encourage conservationists to look beyond documenting forest elephant population decline and address the causes of these declines when developing conversation strategies. We suggest assessing the effectiveness of the existing protected-area networks for landscape connectivity in light of current industrial and infrastructure development. Longitudinal assessments of the effects of landscape changes on forest elephant sociality and behavior are also needed. Finally, lessons learned from West African elephant population loss and habitat fragmentation should be used to inform strategies for land-use planning and managing human-elephant interactions. © 2016 Society for Conservation Biology.

Possible combined effects of climate change, deforestation, and harvesting on the epiphyte Catopsis compacta: a multidisciplinary approach

PubMed Central

del Castillo, Rafael F; Trujillo-Argueta, Sonia; Rivera-García, Raul; Gómez-Ocampo, Zaneli; Mondragón-Chaparro, Demetria

2013-01-01

Climate change, habitat loss, and harvesting are potential drivers of species extinction. These factors are unlikely to act on isolation, but their combined effects are poorly understood. We explored these effects in Catopsis compacta, an epiphytic bromeliad commercially harvested in Oaxaca, Mexico. We analyzed local climate change projections, the dynamics of the vegetation patches, the distribution of Catopsis in the patches, together with population genetics and demographic information. A drying and warming climate trend projected by most climate change models may contribute to explain the poor forest regeneration. Catopsis shows a positive mean stochastic population growth. A PVA reveals that quasi-extinction probabilities are not significantly affected by the current levels of harvesting or by a high drop in the frequency of wet years (2%) but increase sharply when harvesting intensity duplicates. Genetic analyses show a high population genetic diversity, and no evidences of population subdivision or a past bottleneck. Colonization mostly takes place on hosts at the edges of the fragments. Over the last 27 years, the vegetation cover has being lost at a 0.028 years−1 rate, but fragment perimeter has increased 0.076 years−1. The increases in fragment perimeter and vegetation openness, likely caused by climate change and logging, appear to increase the habitat of Catopsis, enhance gene flow, and maintain a growing and highly genetically diverse population, in spite of harvesting. Our study evidences conflicting requirements between the epiphytes and their hosts and antagonistic effects of climate change and fragmentation with harvesting on a species that can exploit open spaces in the forest. A full understanding of the consequences of potential threatening factors on species persistence or extinction requires the inspection of the interactions of these factors among each other and their effects on both the focus species and the species on which this species depends. PMID:24198951

Possible combined effects of climate change, deforestation, and harvesting on the epiphyte Catopsis compacta: a multidisciplinary approach.

PubMed

Del Castillo, Rafael F; Trujillo-Argueta, Sonia; Rivera-García, Raul; Gómez-Ocampo, Zaneli; Mondragón-Chaparro, Demetria

2013-10-01

Climate change, habitat loss, and harvesting are potential drivers of species extinction. These factors are unlikely to act on isolation, but their combined effects are poorly understood. We explored these effects in Catopsis compacta, an epiphytic bromeliad commercially harvested in Oaxaca, Mexico. We analyzed local climate change projections, the dynamics of the vegetation patches, the distribution of Catopsis in the patches, together with population genetics and demographic information. A drying and warming climate trend projected by most climate change models may contribute to explain the poor forest regeneration. Catopsis shows a positive mean stochastic population growth. A PVA reveals that quasi-extinction probabilities are not significantly affected by the current levels of harvesting or by a high drop in the frequency of wet years (2%) but increase sharply when harvesting intensity duplicates. Genetic analyses show a high population genetic diversity, and no evidences of population subdivision or a past bottleneck. Colonization mostly takes place on hosts at the edges of the fragments. Over the last 27 years, the vegetation cover has being lost at a 0.028 years(-1) rate, but fragment perimeter has increased 0.076 years(-1). The increases in fragment perimeter and vegetation openness, likely caused by climate change and logging, appear to increase the habitat of Catopsis, enhance gene flow, and maintain a growing and highly genetically diverse population, in spite of harvesting. Our study evidences conflicting requirements between the epiphytes and their hosts and antagonistic effects of climate change and fragmentation with harvesting on a species that can exploit open spaces in the forest. A full understanding of the consequences of potential threatening factors on species persistence or extinction requires the inspection of the interactions of these factors among each other and their effects on both the focus species and the species on which this species depends.

Expected social utility of life time in the presence of a chronic disease.

PubMed

Mulder, P G; Hempenius, A L

1993-10-01

Interventive action aimed at reducing the incidence of an irreversible chronic noncommunicable disease in a population has various effects. Hopefully, it increases total longevity in the population and it causes the disease to develop later in time in a smaller portion of the population. In this paper a statistical model is built by which these effects can be estimated. A three dimensional probability density function that underlies this model is changed by the interventive action. It is shown how a three dimensional utility function can be defined to appropriately judge this change.

[High frequency of ancestral allele of the TJP1 polymorphism rs2291166 in Mexican population, conformational effect and applications in surgery and medicine].

PubMed

Ramirez-Garcia, Sergio Alberto; Flores-Alvarado, Luis Javier; Topete-González, Luz Rosalba; Charles-Niño, Claudia; Mazariegos-Rubi, Manuel; Dávalos-Rodríguez, Nory Omayra

2016-01-01

TJP1 gene encodes a ZO-1 protein that is required for the recruitment of occludins and claudins in tight junction, and is involved in cell polarisation. It has different variations, the frequency of which has been studied in different populations. In Mexico there are no studies of this gene. These are required because their polymorphisms can be used in studies associated with medicine and surgery. Therefore, the aim of this study was to estimate the frequency of alleles and genotypes of rs2291166 gene polymorphism TJP1 in Mexico Mestizos population, and to estimate the conformational effect of an amino acid change. A total of 473 individuals were included. The rs2291166 polymorphism was identified PASA PCR-7% PAGE, and stained with silver nitrate. The conformational effect of amino acid change was performed in silico, and was carried out with servers ProtPraram Tool and Search Database with Fasta. The most frequent allele in the two populations is the ancestral allele (T). A genotype distribution similar to other populations was found. The polymorphism is in Hardy-Weinberg, p>0.05. Changing aspartate to alanine produced a conformational change. The study reveals a high frequency of the ancestral allele at rs2291166 polymorphism in the Mexican population. Copyright © 2015 Academia Mexicana de Cirugía A.C. Published by Masson Doyma México S.A. All rights reserved.

Sand lizard (Lacerta agilis) phenology in a warming world.

PubMed

Ljungström, Gabriella; Wapstra, Erik; Olsson, Mats

2015-10-08

Present-day climate change has altered the phenology (the timing of periodic life cycle events) of many plant and animal populations worldwide. Some of these changes have been adaptive, leading to an increase in population fitness, whereas others have been associated with fitness decline. Representing short-term responses to an altered weather regime, hitherto observed changes are largely explained by phenotypic plasticity. However, to track climatically induced shifts in optimal phenotype as climate change proceeds, evolutionary capacity in key limiting climate- and fitness-related traits is likely to be crucial. In order to produce realistic predictions about the effects of climate change on species and populations, a main target for conservation biologists is thus to assess the potential of natural populations to respond by these two mechanisms. In this study we use a large 15-year dataset on an ectotherm model, the Swedish sand lizard (Lacerta agilis), to investigate how higher spring temperature is likely to affect oviposition timing in a high latitude population, a trait strongly linked to offspring fitness and survival. With an interest in both the short- and potential long-term effect of rising temperatures, we applied a random regression model, which yields estimates of population-level plasticity and among-individual variation in the average, as well as the plastic, response to temperature. Population plasticity represents capacity for short-term adjustments whereas variation among individuals in a fitness-related trait indicates an opportunity for natural selection and hence for evolutionary adaptation. The analysis revealed both population-level plasticity and individual-level variation in average laying date. In contrast, we found no evidence for variation among females in their plastic responses to spring temperature, which could demonstrate a similarity in responses amongst females, but may also be due to a lack of statistical power to detect such an effect. Our findings indicate that climate warming may have positive fitness effects in this lizard population through an advancement of oviposition date. This prediction is consistent over shorter and potentially also longer time scales as the analysis revealed both population-level plasticity and individual-level variation in average laying date. However, the genetic basis for this variation would have to be examined in order to predict an evolutionary response.

Ocean Acidification Effects on Atlantic Cod Larval Survival and Recruitment to the Fished Population

PubMed Central

Stiasny, Martina H.; Mittermayer, Felix H.; Sswat, Michael; Voss, Rüdiger; Jutfelt, Fredrik; Chierici, Melissa; Puvanendran, Velmurugu; Mortensen, Atle; Reusch, Thorsten B. H.; Clemmesen, Catriona

2016-01-01

How fisheries will be impacted by climate change is far from understood. While some fish populations may be able to escape global warming via range shifts, they cannot escape ocean acidification (OA), an inevitable consequence of the dissolution of anthropogenic carbon dioxide (CO2) emissions in marine waters. How ocean acidification affects population dynamics of commercially important fish species is critical for adapting management practices of exploited fish populations. Ocean acidification has been shown to impair fish larvae’s sensory abilities, affect the morphology of otoliths, cause tissue damage and cause behavioural changes. Here, we obtain first experimental mortality estimates for Atlantic cod larvae under OA and incorporate these effects into recruitment models. End-of-century levels of ocean acidification (~1100 μatm according to the IPCC RCP 8.5) resulted in a doubling of daily mortality rates compared to present-day CO2 concentrations during the first 25 days post hatching (dph), a critical phase for population recruitment. These results were consistent under different feeding regimes, stocking densities and in two cod populations (Western Baltic and Barents Sea stock). When mortality data were included into Ricker-type stock-recruitment models, recruitment was reduced to an average of 8 and 24% of current recruitment for the two populations, respectively. Our results highlight the importance of including vulnerable early life stages when addressing effects of climate change on fish stocks. PMID:27551924

Ocean Acidification Effects on Atlantic Cod Larval Survival and Recruitment to the Fished Population.

PubMed

Stiasny, Martina H; Mittermayer, Felix H; Sswat, Michael; Voss, Rüdiger; Jutfelt, Fredrik; Chierici, Melissa; Puvanendran, Velmurugu; Mortensen, Atle; Reusch, Thorsten B H; Clemmesen, Catriona

2016-01-01

How fisheries will be impacted by climate change is far from understood. While some fish populations may be able to escape global warming via range shifts, they cannot escape ocean acidification (OA), an inevitable consequence of the dissolution of anthropogenic carbon dioxide (CO2) emissions in marine waters. How ocean acidification affects population dynamics of commercially important fish species is critical for adapting management practices of exploited fish populations. Ocean acidification has been shown to impair fish larvae's sensory abilities, affect the morphology of otoliths, cause tissue damage and cause behavioural changes. Here, we obtain first experimental mortality estimates for Atlantic cod larvae under OA and incorporate these effects into recruitment models. End-of-century levels of ocean acidification (~1100 μatm according to the IPCC RCP 8.5) resulted in a doubling of daily mortality rates compared to present-day CO2 concentrations during the first 25 days post hatching (dph), a critical phase for population recruitment. These results were consistent under different feeding regimes, stocking densities and in two cod populations (Western Baltic and Barents Sea stock). When mortality data were included into Ricker-type stock-recruitment models, recruitment was reduced to an average of 8 and 24% of current recruitment for the two populations, respectively. Our results highlight the importance of including vulnerable early life stages when addressing effects of climate change on fish stocks.

A Demographic Deficit? Local Population Aging and Access to Services in Rural America, 1990–2010

PubMed Central

Thiede, Brian; Brown, David L.; Sanders, Scott R.; Glasgow, Nina; Kulcsar, Laszlo J.

2017-01-01

Population aging is being experienced by many rural communities in the U.S., as evidenced by increases in the median age and the high incidence of natural population decrease. The implications of these changes in population structure for the daily lives of the residents in such communities have received little attention. We address this issue in the current study by examining the relationship between population aging and the availability of service-providing establishments in the rural U.S. between 1990 and 2010. Using data mainly from the U.S. Census Bureau and the Bureau of Labor Statistics, we estimate a series of fixed-effects regression models to identify the relationship between median age and establishment counts net of changes in overall population and other factors. We find a significant, but non-linear relationship between county median age and the total number of service-providing establishments, and counts of most specific types of services. We find a positive effect of total population size across all of our models. This total population effect is consistent with other research, but the independent effects of age structure that we observe represent a novel finding and suggest that age structure is a salient factor in local rural development and community wellbeing. PMID:28757660

How Resource Phenology Affects Consumer Population Dynamics.

PubMed

Bewick, Sharon; Cantrell, R Stephen; Cosner, Chris; Fagan, William F

2016-02-01

Climate change drives uneven phenology shifts across taxa, and this can result in changes to the phenological match between interacting species. Shifts in the relative phenology of partner species are well documented, but few studies have addressed the effects of such changes on population dynamics. To explore this, we develop a phenologically explicit model describing consumer-resource interactions. Focusing on scenarios for univoltine insects, we show how changes in resource phenology can be reinterpreted as transformations in the year-to-year recursion relationships defining consumer population dynamics. This perspective provides a straightforward path for interpreting the long-term population consequences of phenology change. Specifically, by relating the outcome of phenological shifts to species traits governing recursion relationships (e.g., consumer fecundity or competitive scenario), we demonstrate how changes in relative phenology can force systems into different dynamical regimes, with major implications for resource management, conservation, and other areas of applied dynamics.

Social Marketing, Stages of Change, and Public Health Smoking Interventions

ERIC Educational Resources Information Center

Diehr, Paula; Hannon, Peggy; Pizacani, Barbara; Forehand, Mark; Meischke, Hendrika; Curry, Susan; Martin, Diane P.; Weaver, Marcia R.; Harris, Jeffrey

2011-01-01

As a "thought experiment," the authors used a modified stages of change model for smoking to define homogeneous segments within various hypothetical populations. The authors then estimated the population effect of public health interventions that targeted the different segments. Under most assumptions, interventions that emphasized primary and…

Bottom-up regulation of a pole-ward migratory predator population

PubMed Central

van den Hoff, John; McMahon, Clive R.; Simpkins, Graham R.; Hindell, Mark A.; Alderman, Rachael; Burton, Harry R.

2014-01-01

As the effects of regional climate change are most pronounced at polar latitudes, we might expect polar-ward migratory populations to respond as habitat suitability changes. The southern elephant seal (Mirounga leonina L.) is a pole-ward migratory species whose populations have mostly stabilized or increased in the past decade, the one exception being the Macquarie Island population which has decreased continuously over the past 50 years. To explore probable causes of this anomalous trend, we counted breeding female seals annually between 1988 and 2011 in order to relate annual rates of population change (r) to foraging habitat changes that have known connections with atmospheric variability. We found r (i) varied annually from −0.016 to 0.021 over the study period, (ii) was most effected by anomalous atmospheric variability after a 3 year time lag was introduced (R = 0.51) and (iii) was associated with sea-ice duration (SID) within the seals’ foraging range at the same temporal lag. Negative r years may be extrapolated to explain, at least partially, the overall trend in seal abundance at Macquarie Island; specifically, increasing SID within the seals foraging range has a negative influence on their abundance at the island. Evidence is accruing that suggests southern elephant seal populations may respond positively to a reduced sea-ice field. PMID:24619437

Adaptations of an RNA virus to increasing thermal stress

PubMed Central

Singhal, Sonia; Leon Guerrero, Cierra M.; Whang, Stella G.; McClure, Erin M.; Busch, Hannah G.; Kerr, Benjamin

2017-01-01

Environments can change in incremental fashions, where a shift from one state to another occurs over multiple organismal generations. The rate of the environmental change is expected to influence how and how well populations adapt to the final environmental state. We used a model system, the lytic RNA bacteriophage Φ6, to investigate this question empirically. We evolved viruses for thermostability by exposing them to heat shocks that increased to a maximum temperature at different rates. We observed increases in the ability of many heat-shocked populations to survive high temperature heat shocks. On their first exposure to the highest temperature, populations that experienced a gradual increase in temperature had higher average survival than populations that experienced a rapid temperature increase. However, at the end of the experiment, neither the survival of populations at the highest temperature nor the number of mutations per population varied significantly according to the rate of thermal change. We also evaluated mutations from the endpoint populations for their effects on viral thermostability and growth. As expected, some mutations did increase viral thermostability. However, other mutations decreased thermostability but increased growth rate, suggesting that benefits of an increased replication rate may have sometimes outweighed the benefits of enhanced thermostability. Our study highlights the importance of considering the effects of multiple selective pressures, even in environments where a single factor changes. PMID:29267297

Quantifying changes and influences on mottled duck density in Texas

USGS Publications Warehouse

Ross, Beth; Haukos, David A.; Walther, Patrick

2018-01-01

Understanding the relative influence of environmental and intrinsic effects on populations is important for managing and conserving harvested species, especially those species inhabiting changing environments. Additionally, climate change can increase the uncertainty associated with management of species in these changing environments, making understanding factors affecting their populations even more important. Coastal ecosystems are particularly threatened by climate change; the combined effects of increasing severe weather events, sea level rise, and drought will likely have non-linear effects on coastal marsh wildlife species and their associated habitats. A species of conservation concern that persists in these coastal areas is the mottled duck (Anas fulvigula). Mottled ducks in the western Gulf Coast are approximately 50% below target abundance numbers established by the Gulf Coast Joint Venture for Texas and Louisiana, USA. Although evidence for declines in mottled duck abundance is apparent, specific causes of the decrease remain unknown. Our goals were to determine where the largest declines in mottled duck population were occurring along the system of Texas Gulf Coast National Wildlife Refuges and quantify the relative contribution of environmental and intrinsic effects on changes to relative population density. We modeled aerial survey data of mottled duck density along the Texas Gulf Coast from 1986–2015 to quantify effects of extreme weather events on an index to mottled duck density using the United States Climate Extremes Index and Palmer Drought Severity Index. Our results indicate that decreases in abundance are best described by an increase in days with extreme 1-day precipitation from June to November (hurricane season) and an increase in drought severity. Better understanding those portions of the life cycle affected by environmental conditions, and how to manage mottled duck habitat in conjunction with these events will likely be key to persistence of the species under future environmental conditions.

Evolution of plant–pollinator mutualisms in response to climate change

PubMed Central

Gilman, R Tucker; Fabina, Nicholas S; Abbott, Karen C; Rafferty, Nicole E

2012-01-01

Climate change has the potential to desynchronize the phenologies of interdependent species, with potentially catastrophic effects on mutualist populations. Phenologies can evolve, but the role of evolution in the response of mutualisms to climate change is poorly understood. We developed a model that explicitly considers both the evolution and the population dynamics of a plant–pollinator mutualism under climate change. How the populations evolve, and thus whether the populations and the mutualism persist, depends not only on the rate of climate change but also on the densities and phenologies of other species in the community. Abundant alternative mutualist partners with broad temporal distributions can make a mutualism more robust to climate change, while abundant alternative partners with narrow temporal distributions can make a mutualism less robust. How community composition and the rate of climate change affect the persistence of mutualisms is mediated by two-species Allee thresholds. Understanding these thresholds will help researchers to identify those mutualisms at highest risk owing to climate change. PMID:25568025

Climate, Anchovy, and Sardine.

PubMed

Checkley, David M; Asch, Rebecca G; Rykaczewski, Ryan R

2017-01-03

Anchovy and sardine populated productive ocean regions over hundreds of thousands of years under a naturally varying climate, and are now subject to climate change of equal or greater magnitude occurring over decades to centuries. We hypothesize that anchovy and sardine populations are limited in size by the supply of nitrogen from outside their habitats originating from upwelling, mixing, and rivers. Projections of the responses of anchovy and sardine to climate change rely on a range of model types and consideration of the effects of climate on lower trophic levels, the effects of fishing on higher trophic levels, and the traits of these two types of fish. Distribution, phenology, nutrient supply, plankton composition and production, habitat compression, fishing, and acclimation and adaptation may be affected by ocean warming, acidification, deoxygenation, and altered hydrology. Observations of populations and evaluation of model skill are essential to resolve the effects of climate change on these fish.

Climate, Anchovy, and Sardine

NASA Astrophysics Data System (ADS)

Checkley, David M.; Asch, Rebecca G.; Rykaczewski, Ryan R.

2017-01-01

Anchovy and sardine populated productive ocean regions over hundreds of thousands of years under a naturally varying climate, and are now subject to climate change of equal or greater magnitude occurring over decades to centuries. We hypothesize that anchovy and sardine populations are limited in size by the supply of nitrogen from outside their habitats originating from upwelling, mixing, and rivers. Projections of the responses of anchovy and sardine to climate change rely on a range of model types and consideration of the effects of climate on lower trophic levels, the effects of fishing on higher trophic levels, and the traits of these two types of fish. Distribution, phenology, nutrient supply, plankton composition and production, habitat compression, fishing, and acclimation and adaptation may be affected by ocean warming, acidification, deoxygenation, and altered hydrology. Observations of populations and evaluation of model skill are essential to resolve the effects of climate change on these fish.

UNICOR Users Manual

Treesearch

E. L. Landguth; B. K. Hand; J. M. Glassy; S. A. Cushman; R. T. Carlson

2011-01-01

Habitat loss and its effects on populations of vulnerable species is among the most urgent problems in conservation ecology. It is critical that managers and scientists have effective tools to evaluate the effects of landuse and climate change on the extent and connectivity of populations. To address this need, we introduce UNIversal CORridor network simulator (UNICOR...

Rate of language evolution is affected by population size

PubMed Central

Bromham, Lindell; Hua, Xia; Fitzpatrick, Thomas G.; Greenhill, Simon J.

2015-01-01

The effect of population size on patterns and rates of language evolution is controversial. Do languages with larger speaker populations change faster due to a greater capacity for innovation, or do smaller populations change faster due to more efficient diffusion of innovations? Do smaller populations suffer greater loss of language elements through founder effects or drift, or do languages with more speakers lose features due to a process of simplification? Revealing the influence of population size on the tempo and mode of language evolution not only will clarify underlying mechanisms of language change but also has practical implications for the way that language data are used to reconstruct the history of human cultures. Here, we provide, to our knowledge, the first empirical, statistically robust test of the influence of population size on rates of language evolution, controlling for the evolutionary history of the populations and formally comparing the fit of different models of language evolution. We compare rates of gain and loss of cognate words for basic vocabulary in Polynesian languages, an ideal test case with a well-defined history. We demonstrate that larger populations have higher rates of gain of new words whereas smaller populations have higher rates of word loss. These results show that demographic factors can influence rates of language evolution and that rates of gain and loss are affected differently. These findings are strikingly consistent with general predictions of evolutionary models. PMID:25646448

Adaptation, extinction and global change

PubMed Central

Bell, Graham; Collins, Sinéad

2008-01-01

We discuss three interlinked issues: the natural pace of environmental change and adaptation, the likelihood that a population will adapt to a potentially lethal change, and adaptation to elevated CO2, the prime mover of global change. Environmental variability is governed by power laws showing that ln difference in conditions increases with ln elapsed time at a rate of 0.3–0.4. This leads to strong but fluctuating selection in many natural populations. The effect of repeated adverse change on mean fitness depends on its frequency rather than its severity. If the depression of mean fitness leads to population decline, however, severe stress may cause extinction. Evolutionary rescue from extinction requires abundant genetic variation or a high mutation supply rate, and thus a large population size. Although natural populations can sustain quite intense selection, they often fail to adapt to anthropogenic stresses such as pollution and acidification and instead become extinct. Experimental selection lines of algae show no specific adaptation to elevated CO2, but instead lose their carbon-concentrating mechanism through mutational degradation. This is likely to reduce the effectiveness of the oceanic carbon pump. Elevated CO2 is also likely to lead to changes in phytoplankton community composition, although it is not yet clear what these will be. We emphasize the importance of experimental evolution in understanding and predicting the biological response to global change. This will be one of the main tasks of evolutionary biologists in the coming decade. PMID:25567487

Endogenous technological and population change under increasing water scarcity

NASA Astrophysics Data System (ADS)

Pande, S.; Ertsen, M.; Sivapalan, M.

2014-08-01

Ancient civilizations may have dispersed or collapsed under extreme dry conditions. There are indications that the same may hold for modern societies. However, hydroclimatic change cannot be the sole predictor of the fate of contemporary societies in water-scarce regions. This paper focuses on technological change as a factor that may ameliorate the effects of increasing water scarcity and as such counter the effects of hydroclimatic changes. We study the role of technological change on the dynamics of coupled human-water systems, and model technological change as an endogenous process that depends on many factors intrinsic to coupled human-water dynamics. We do not treat technology as an exogenous random sequence of events, but assume that it results from societal actions. While the proposed model is a rather simple model of a coupled human-water system, it is shown to be capable of replicating patterns of technological, population, production and consumption per capita changes. The model demonstrates that technological change may indeed ameliorate the effects of increasing water scarcity, but typically it does so only to a certain extent. In general we find that endogenous technology change under increasing water scarcity helps to delay the peak of population size before it inevitably starts to decline. We also analyze the case when water remains constant over time and find that co-evolutionary trajectories can never grow at a constant rate; rather the rate itself grows with time. Thus our model does not predict a co-evolutionary trajectory of a socio-hydrological system where technological innovation harmoniously provides for a growing population. It allows either for an explosion or an eventual dispersal of population. The latter occurs only under increasing water scarcity. As a result, we draw the conclusion that declining consumption per capita despite technological advancement and increase in aggregate production may serve as a useful predictor of upcoming decline in contemporary societies in water-scarce basins.

More rapid climate change promotes evolutionary rescue through selection for increased dispersal distance

PubMed Central

Boeye, Jeroen; Travis, Justin M J; Stoks, Robby; Bonte, Dries

2013-01-01

Species can either adapt to new conditions induced by climate change or shift their range in an attempt to track optimal environmental conditions. During current range shifts, species are simultaneously confronted with a second major anthropogenic disturbance, landscape fragmentation. Using individual-based models with a shifting climate window, we examine the effect of different rates of climate change on the evolution of dispersal distances through changes in the genetically determined dispersal kernel. Our results demonstrate that the rate of climate change is positively correlated to the evolved dispersal distances although too fast climate change causes the population to crash. When faced with realistic rates of climate change, greater dispersal distances evolve than those required for the population to keep track of the climate, thereby maximizing population size. Importantly, the greater dispersal distances that evolve when climate change is more rapid, induce evolutionary rescue by facilitating the population in crossing large gaps in the landscape. This could ensure population persistence in case of range shifting in fragmented landscapes. Furthermore, we highlight problems in using invasion speed as a proxy for potential range shifting abilities under climate change. PMID:23467649

Do sudden air temperature and pressure changes affect cardiovascular morbidity and mortality?

NASA Astrophysics Data System (ADS)

Plavcová, E.; Davídkovová, H.; Kyselý, J.

2012-04-01

Previous studies have shown that sudden changes in weather (usually represented by air temperature and/or pressure) are associated with increases in daily mortality. Little is understood about physiological mechanisms responsible for the impacts of weather changes on mortality, and whether similar patterns appear for morbidity as well. Relatively little is known also about differences in the magnitude of the mortality response in provincial regions and in cities, where the impacts may be exacerbated by air pollution effects and/or heat island. The present study examines the effects of sudden air temperature and pressure changes on morbidity (represented by hospital admissions) and mortality due to cardiovascular diseases in the population of the Czech Republic (approx. 10 million inhabitants) and separately in the city of Prague (1.2 million inhabitants). The events are selected from data covering 1994-2009 using the methodology introduced by Plavcová and Kyselý (2010), and they are compared with the datasets on hospital admissions and daily mortality (both standardized to account for long-term changes and the seasonal and weekly cycles). Relative deviations of morbidity/mortality from the baseline were averaged over the selected events for days D-2 (2 days before a change) up to D+7 (7 days after), and their statistical significance was tested by means of the Monte Carlo method. The study aims at (i) identifying those weather changes associated with increased cardiovascular morbidity/mortality, separately in summer and winter, (ii) comparing the effects of weather changes on morbidity and mortality, (iii) identifying whether urban population of Prague is more/less vulnerable in comparison to the population of the whole Czech Republic, (iv) comparing the effects for different cardiovascular diseases (ischaemic heart diseases, ICD-10 codes I20-I25; cerebrovascular diseases, I60-I69; hypertension, I10; atherosclerosis, I70) and individual population groups (by age and gender), and (v) identifying physiological mechanisms which play roles in deteriorating health conditions of vulnerable population groups. Plavcová E., Kyselý J., 2010: Relationships between sudden weather changes in summer and mortality in the Czech Republic, 1986-2005. International Journal of Biometeorology, 54, 539-551 [doi 10.1007/s00484-010-0303-7

Changes of scaling relationships in an evolving population: The example of "sedimentary" stylolites

NASA Astrophysics Data System (ADS)

Peacock, D. C. P.; Korneva, I.; Nixon, C. W.; Rotevatn, A.

2017-03-01

Bed-parallel (;sedimentary;) stylolites are used as an example of a population that evolves by the addition of new components, their growth and their merger. It is shown that this style of growth controls the changes in the scaling relationships of the population. Stylolites tend to evolve in carbonate rocks through time, for example by compaction during progressive burial. The evolution of a population of stylolites, and their likely effects on porosity, are demonstrated using simple numerical models. Starting with a power-law distribution, the adding of new stylolites, the increase in their amplitudes and their merger decrease the slope of magnitude versus cumulative frequency of the population. The population changes to a non-power-law distribution as smaller stylolites merge to form larger stylolites. The results suggest that other populations can be forward- or backward-modelled, such as fault lengths, which also evolve by the addition of components, their growth and merger. Consideration of the ways in which populations change improves understanding of scaling relationships and vice versa, and would assist in the management of geofluid reservoirs.

Modeling the effects of land use and climate change on riverine smallmouth bass

USGS Publications Warehouse

Peterson, J.T.; Kwak, T.J.

1999-01-01

Anthropogenic changes in temperature and stream flow, associated with watershed land use and climate change, are critical influences on the distribution and abundance of riverine fishes. To project the effects of changing land use and climate, we modeled a smallmouth bass (Micropterus dolomieu) population in a midwestern USA, large river- floodplain ecosystem under historical (1915-1925), present (1977-1990), and future (2060, influenced by climate change) temperature and flow regimes. The age-structured model included parameters for temperature and river discharge during critical seasonal periods, fish population dynamics, and fishing harvest. Model relationships were developed from empirical field data collected over a 13-yr period. Sensitivity analyses indicated that discharge during the spawning/rearing period had a greater effect on adult density and fishing yield than did spawning/rearing temperature or winter discharge. Simulations for 100 years projected a 139% greater mean fish density under a historical flow regime (64.9 fish/ha) than that estimated for the present (27.1 fish/ha) with a sustainable fishing harvest under both flow regimes. Simulations under future climate-change-induced temperature and flow regimes with present land use projected a 69% decrease in mean fish density (8.5 fish/ha) from present and an unstable population that went extinct during 56% of the simulations. However, when simulated under a future climate-altered temperature and flow regime with historical land use, the population increased by 66% (45.0 fish/ha) from present and sustained a harvest. Our findings suggest that land-use changes may be a greater detriment to riverine fishes than projected climate change and that the combined effects of both factors may lead to local species extinction. However, the negative effects of increased temperature and precipitation associated with future global warming could be mitigated by river channel, floodplain, and watershed restoration.

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

PubMed

Vedder, Oscar; Bouwhuis, Sandra; Sheldon, Ben C

2013-07-01

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.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu Qin, E-mail: zhuqin@fudan.edu.cn; Peng Xizhe, E-mail: xzpeng@fudan.edu.cn

This study examines the impacts of population size, population structure, and consumption level on carbon emissions in China from 1978 to 2008. To this end, we expanded the stochastic impacts by regression on population, affluence, and technology model and used the ridge regression method, which overcomes the negative influences of multicollinearity among independent variables under acceptable bias. Results reveal that changes in consumption level and population structure were the major impact factors, not changes in population size. Consumption level and carbon emissions were highly correlated. In terms of population structure, urbanization, population age, and household size had distinct effects onmore » carbon emissions. Urbanization increased carbon emissions, while the effect of age acted primarily through the expansion of the labor force and consequent overall economic growth. Shrinking household size increased residential consumption, resulting in higher carbon emissions. Households, rather than individuals, are a more reasonable explanation for the demographic impact on carbon emissions. Potential social policies for low carbon development are also discussed. - Highlights: Black-Right-Pointing-Pointer We examine the impacts of population change on carbon emissions in China. Black-Right-Pointing-Pointer We expand the STIRPAT model by containing population structure factors in the model. Black-Right-Pointing-Pointer The population structure includes age structure, urbanization level, and household size. Black-Right-Pointing-Pointer The ridge regression method is used to estimate the model with multicollinearity. Black-Right-Pointing-Pointer The population structure plays a more important role compared with the population size.« less

Population density of North American elk: effects on plant diversity.

PubMed

Stewart, Kelley M; Bowyer, R Terry; Kie, John G; Dick, Brian L; Ruess, Roger W

2009-08-01

Large, herbivorous mammals have profound effects on ecosystem structure and function and often act as keystone species in ecosystems they inhabit. Density-dependent processes associated with population structure of large mammals may interact with ecosystem functioning to increase or decrease biodiversity, depending on the relationship of herbivore populations relative to the carrying capacity (K) of the ecosystem. We tested for indirect effects of population density of large herbivores on plant species richness and diversity in a montane ecosystem, where increased net aboveground primary productivity (NAPP) in response to low levels of herbivory has been reported. We documented a positive, linear relationship between plant-species diversity and richness with NAPP. Structural equation modeling revealed significant indirect relationships between population density of herbivores, NAPP, and species diversity. We observed an indirect effect of density-dependent processes in large, herbivorous mammals and species diversity of plants through changes in NAPP in this montane ecosystem. Changes in species diversity of plants in response to herbivory may be more indirect in ecosystems with long histories of herbivory. Those subtle or indirect effects of herbivory may have strong effects on ecosystem functioning, but may be overlooked in plant communities that are relatively resilient to herbivory.

Shifts of community composition and population density substantially affect ecosystem function despite invariant richness.

PubMed

Spaak, Jurg W; Baert, Jan M; Baird, Donald J; Eisenhauer, Nico; Maltby, Lorraine; Pomati, Francesco; Radchuk, Viktoriia; Rohr, Jason R; Van den Brink, Paul J; De Laender, Frederik

2017-10-01

There has been considerable focus on the impacts of environmental change on ecosystem function arising from changes in species richness. However, environmental change may affect ecosystem function without affecting richness, most notably by affecting population densities and community composition. Using a theoretical model, we find that, despite invariant richness, (1) small environmental effects may already lead to a collapse of function; (2) competitive strength may be a less important determinant of ecosystem function change than the selectivity of the environmental change driver and (3) effects on ecosystem function increase when effects on composition are larger. We also present a complementary statistical analysis of 13 data sets of phytoplankton and periphyton communities exposed to chemical stressors and show that effects on primary production under invariant richness ranged from -75% to +10%. We conclude that environmental protection goals relying on measures of richness could underestimate ecological impacts of environmental change. © 2017 The Authors Ecology Letters published by CNRS and John Wiley & Sons Ltd.

Body size and allometric shape variation in the molly Poecilia vivipara along a gradient of salinity and predation.

PubMed

Araújo, Márcio S; Perez, S Ivan; Magazoni, Maria Julia C; Petry, Ana C

2014-12-04

Phenotypic diversity among populations may result from divergent natural selection acting directly on traits or via correlated responses to changes in other traits. One of the most frequent patterns of correlated response is the proportional change in the dimensions of anatomical traits associated with changes in growth or absolute size, known as allometry. Livebearing fishes subject to predation gradients have been shown to repeatedly evolve larger caudal peduncles and smaller cranial regions under high predation regimes. Poecilia vivipara is a livebearing fish commonly found in coastal lagoons in the north of the state of Rio de Janeiro, Brazil. Similar to what is observed in other predation gradients, lagoons inhabited by P. vivipara vary in the presence of piscivorous fishes; contrary to other poeciliid systems, populations of P. vivipara vary greatly in body size, which opens the possibility of strong allometric effects on shape variation. Here we investigated body shape diversification among six populations of P. vivipara along a predation gradient and its relationship with allometric trajectories within and among populations. We found substantial body size variation and correlated shape changes among populations. Multivariate regression analysis showed that size variation among populations accounted for 66% of shape variation in females and 38% in males, suggesting that size is the most important dimension underlying shape variation among populations of P. vivipara in this system. Changes in the relative sizes of the caudal peduncle and cranial regions were only partly in line with predictions from divergent natural selection associated with predation regime. Our results suggest the possibility that adaptive shape variation among populations has been partly constrained by allometry in P. vivipara. Processes governing body size changes are therefore important in the diversification of this species. We conclude that in species characterized by substantial among-population differences in body size, ignoring allometric effects when investigating divergent natural selection's role in phenotypic diversification might not be warranted.

Family Planning and Deforestation: Evidence from the Ecuadorian Amazon.

PubMed

Sellers, Samuel

2017-06-01

Despite an abundant body of literature exploring the relationship between population growth and forest cover change, comparatively little research has explored the forest cover impacts of family planning use, which is a key determinant of the rate of population growth in many developing country contexts. Using data from a farm-level panel survey in the Northern Ecuadorian Amazon, this paper addresses whether family planning use impacts forest cover change. Longitudinal model results show that after controlling for household life cycle and land use variables, family planning use did not have an independent effect on deforestation, reforestation, or net forest loss between 1990 and 2008. Forest cover change patterns appear indicative of farm life cycle effects. However, family planning use is associated with reduced subsequent fertility among households, suggesting that the relationship between population growth from births and forest cover change may be limited in this setting.

Family Planning and Deforestation: Evidence from the Ecuadorian Amazon

PubMed Central

Sellers, Samuel

2017-01-01

Despite an abundant body of literature exploring the relationship between population growth and forest cover change, comparatively little research has explored the forest cover impacts of family planning use, which is a key determinant of the rate of population growth in many developing country contexts. Using data from a farm-level panel survey in the Northern Ecuadorian Amazon, this paper addresses whether family planning use impacts forest cover change. Longitudinal model results show that after controlling for household life cycle and land use variables, family planning use did not have an independent effect on deforestation, reforestation, or net forest loss between 1990 and 2008. Forest cover change patterns appear indicative of farm life cycle effects. However, family planning use is associated with reduced subsequent fertility among households, suggesting that the relationship between population growth from births and forest cover change may be limited in this setting. PMID:29056808

Does source population size affect performance in new environments?

PubMed Central

Yates, Matthew C; Fraser, Dylan J

2014-01-01

Small populations are predicted to perform poorly relative to large populations when experiencing environmental change. To explore this prediction in nature, data from reciprocal transplant, common garden, and translocation studies were compared meta-analytically. We contrasted changes in performance resulting from transplantation to new environments among individuals originating from different sized source populations from plants and salmonids. We then evaluated the effect of source population size on performance in natural common garden environments and the relationship between population size and habitat quality. In ‘home-away’ contrasts, large populations exhibited reduced performance in new environments. In common gardens, the effect of source population size on performance was inconsistent across life-history stages (LHS) and environments. When transplanted to the same set of new environments, small populations either performed equally well or better than large populations, depending on life stage. Conversely, large populations outperformed small populations within native environments, but only at later life stages. Population size was not associated with habitat quality. Several factors might explain the negative association between source population size and performance in new environments: (i) stronger local adaptation in large populations and antagonistic pleiotropy, (ii) the maintenance of genetic variation in small populations, and (iii) potential environmental differences between large and small populations. PMID:25469166

Empty Niches after Extinctions Increase Population Sizes of Modern Corals.

PubMed

Prada, Carlos; Hanna, Bishoy; Budd, Ann F; Woodley, Cheryl M; Schmutz, Jeremy; Grimwood, Jane; Iglesias-Prieto, Roberto; Pandolfi, John M; Levitan, Don; Johnson, Kenneth G; Knowlton, Nancy; Kitano, Hiroaki; DeGiorgio, Michael; Medina, Mónica

2016-12-05

Large environmental fluctuations often cause mass extinctions, extirpating species and transforming communities [1, 2]. While the effects on community structure are evident in the fossil record, demographic consequences for populations of individual species are harder to evaluate because fossils reveal relative, but not absolute, abundances. However, genomic analyses of living species that have survived a mass extinction event offer the potential for understanding the demographic effects of such environmental fluctuations on extant species. Here, we show how environmental variation since the Pliocene has shaped demographic changes in extant corals of the genus Orbicella, major extant reef builders in the Caribbean that today are endangered. We use genomic approaches to estimate previously unknown current and past population sizes over the last 3 million years. Populations of all three Orbicella declined around 2-1 million years ago, coincident with the extinction of at least 50% of Caribbean coral species. The estimated changes in population size are consistent across the three species despite their ecological differences. Subsequently, two shallow-water specialists expanded their population sizes at least 2-fold, over a time that overlaps with the disappearance of their sister competitor species O. nancyi (the organ-pipe Orbicella). Our study suggests that populations of Orbicella species are capable of rebounding from reductions in population size under suitable conditions and that the effective population size of modern corals provides rich standing genetic variation for corals to adapt to climate change. For conservation genetics, our study suggests the need to evaluate genetic variation under appropriate demographic models. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

PubMed Central

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

Population Education: Lessons for a Changing World.

ERIC Educational Resources Information Center

Wasserman, Pamela

1996-01-01

Considers the global effects of a rapidly growing population combined with dwindling natural resources and how these issues might be addressed in the classroom. Includes a population education lesson plan, guiding principles, list of resources, and suggested activities. (MJP)

Effect of water hardness on cardiovascular mortality: an ecological time series approach.

PubMed

Lake, I R; Swift, L; Catling, L A; Abubakar, I; Sabel, C E; Hunter, P R

2010-12-01

Numerous studies have suggested an inverse relationship between drinking water hardness and cardiovascular disease. However, the weight of evidence is insufficient for the WHO to implement a health-based guideline for water hardness. This study followed WHO recommendations to assess the feasibility of using ecological time series data from areas exposed to step changes in water hardness to investigate this issue. Monthly time series of cardiovascular mortality data, subdivided by age and sex, were systematically collected from areas reported to have undergone step changes in water hardness, calcium and magnesium in England and Wales between 1981 and 2005. Time series methods were used to investigate the effect of water hardness changes on mortality. No evidence was found of an association between step changes in drinking water hardness or drinking water calcium and cardiovascular mortality. The lack of areas with large populations and a reasonable change in magnesium levels precludes a definitive conclusion about the impact of this cation. We use our results on the variability of the series to consider the data requirements (size of population, time of water hardness change) for such a study to have sufficient power. Only data from areas with large populations (>500,000) are likely to be able to detect a change of the size suggested by previous studies (rate ratio of 1.06). Ecological time series studies of populations exposed to changes in drinking water hardness may not be able to provide conclusive evidence on the links between water hardness and cardiovascular mortality unless very large populations are studied. Investigations of individuals may be more informative.

Weakening density dependence from climate change and agricultural intensification triggers pest outbreaks: a 37-year observation of cotton bollworms

PubMed Central

Ouyang, Fang; Hui, Cang; Ge, Saiying; Men, Xin-Yuan; Zhao, Zi-Hua; Shi, Pei-Jian; Zhang, Yong-Sheng; Li, Bai-Lian

2014-01-01

Understanding drivers of population fluctuation, especially for agricultural pests, is central to the provision of agro-ecosystem services. Here, we examine the role of endogenous density dependence and exogenous factors of climate and human activity in regulating the 37-year population dynamics of an important agricultural insect pest, the cotton bollworm (Helicoverpa armigera), in North China from 1975 to 2011. Quantitative time-series analysis provided strong evidence explaining long-term population dynamics of the cotton bollworm and its driving factors. Rising temperature and declining rainfall exacerbated the effect of agricultural intensification on continuously weakening the negative density dependence in regulating the population dynamics of cotton bollworms. Consequently, ongoing climate change and agricultural intensification unleashed the tightly regulated pest population and triggered the regional outbreak of H. armigera in 1992. Although the negative density dependence can effectively regulate the population change rate to fluctuate around zero at stable equilibrium levels before and after outbreak in the 1992, the population equilibrium jumped to a higher density level with apparently larger amplitudes after the outbreak. The results highlight the possibility for exogenous factors to induce pest outbreaks and alter the population regulating mechanism of negative density dependence and, thus, the stable equilibrium of the pest population, often to a higher level, posing considerable risks to the provision of agro-ecosystem services and regional food security. Efficient and timely measures of pest management in the era of Anthropocene should target the strengthening and revival of weakening density dependence caused by climate change and human activities. PMID:25535553

Weakening density dependence from climate change and agricultural intensification triggers pest outbreaks: a 37-year observation of cotton bollworms.

PubMed

Ouyang, Fang; Hui, Cang; Ge, Saiying; Men, Xin-Yuan; Zhao, Zi-Hua; Shi, Pei-Jian; Zhang, Yong-Sheng; Li, Bai-Lian

2014-09-01

Understanding drivers of population fluctuation, especially for agricultural pests, is central to the provision of agro-ecosystem services. Here, we examine the role of endogenous density dependence and exogenous factors of climate and human activity in regulating the 37-year population dynamics of an important agricultural insect pest, the cotton bollworm (Helicoverpa armigera), in North China from 1975 to 2011. Quantitative time-series analysis provided strong evidence explaining long-term population dynamics of the cotton bollworm and its driving factors. Rising temperature and declining rainfall exacerbated the effect of agricultural intensification on continuously weakening the negative density dependence in regulating the population dynamics of cotton bollworms. Consequently, ongoing climate change and agricultural intensification unleashed the tightly regulated pest population and triggered the regional outbreak of H. armigera in 1992. Although the negative density dependence can effectively regulate the population change rate to fluctuate around zero at stable equilibrium levels before and after outbreak in the 1992, the population equilibrium jumped to a higher density level with apparently larger amplitudes after the outbreak. The results highlight the possibility for exogenous factors to induce pest outbreaks and alter the population regulating mechanism of negative density dependence and, thus, the stable equilibrium of the pest population, often to a higher level, posing considerable risks to the provision of agro-ecosystem services and regional food security. Efficient and timely measures of pest management in the era of Anthropocene should target the strengthening and revival of weakening density dependence caused by climate change and human activities.

Recent range expansion of a terrestrial orchid corresponds with climate-driven variation in its population dynamics.

PubMed

van der Meer, Sascha; Jacquemyn, Hans; Carey, Peter D; Jongejans, Eelke

2016-06-01

The population dynamics and distribution limits of plant species are predicted to change as the climate changes. However, it remains unclear to what extent climate variables affect population dynamics, which vital rates are most sensitive to climate change, and whether the same vital rates drive population dynamics in different populations. In this study, we used long-term demographic data from two populations of the terrestrial orchid Himantoglossum hircinum growing at the northern edge of their geographic range to quantify the influence of climate change on demographic vital rates. Integral projection models were constructed to study how climate conditions between 1991 and 2006 affected population dynamics and to assess how projected future climate change will affect the long-term viability of this species. Based on the parameterised vital rate functions and the observed climatic conditions, one of the studied populations had an average population growth rate above 1 (λ = 1.04), while the other was declining at ca. 3 % year(-1) (λ = 0.97). Variation in temperature and precipitation mainly affected population growth through their effect on survival and fecundity. Based on UK Climate Projection 2009 estimates of future climate conditions for three greenhouse gas emission scenarios, population growth rates are expected to increase in one of the studied populations. Overall, our results indicate that the observed changes in climatic conditions appeared to be beneficial to the long-term survival of the species in the UK and suggest that they may have been the driving force behind the current range expansion of H. hircinum in England.

Mitigation of climate change impacts on raptors by behavioural adaptation: ecological buffering mechanisms

NASA Astrophysics Data System (ADS)

Wichmann, Matthias C.; Groeneveld, Jürgen; Jeltsch, Florian; Grimm, Volker

2005-07-01

The predicted climate change causes deep concerns on the effects of increasing temperatures and changing precipitation patterns on species viability and, in turn, on biodiversity. Models of Population Viability Analysis (PVA) provide a powerful tool to assess the risk of species extinction. However, most PVA models do not take into account the potential effects of behavioural adaptations. Organisms might adapt to new environmental situations and thereby mitigate negative effects of climate change. To demonstrate such mitigation effects, we use an existing PVA model describing a population of the tawny eagle ( Aquila rapax) in the southern Kalahari. This model does not include behavioural adaptations. We develop a new model by assuming that the birds enlarge their average territory size to compensate for lower amounts of precipitation. Here, we found the predicted increase in risk of extinction due to climate change to be much lower than in the original model. However, this "buffering" of climate change by behavioural adaptation is not very effective in coping with increasing interannual variances. We refer to further examples of ecological "buffering mechanisms" from the literature and argue that possible buffering mechanisms should be given due consideration when the effects of climate change on biodiversity are to be predicted.

Psychology and Population: An Overview.

ERIC Educational Resources Information Center

Fawcett, James T.

Psychology and Population is defined as the study of individual dispositions and behavior that affect the size, structure and dispersion of the population, and the way in which acts of individuals enter into the dynamics of population change. Even this definition was viewed as inadequate, ignoring, as it does, the reciprocal effect of population…

The problem of estimating recent genetic connectivity in a changing world.

PubMed

Samarasin, Pasan; Shuter, Brian J; Wright, Stephen I; Rodd, F Helen

2017-02-01

Accurate understanding of population connectivity is important to conservation because dispersal can play an important role in population dynamics, microevolution, and assessments of extirpation risk and population rescue. Genetic methods are increasingly used to infer population connectivity because advances in technology have made them more advantageous (e.g., cost effective) relative to ecological methods. Given the reductions in wildlife population connectivity since the Industrial Revolution and more recent drastic reductions from habitat loss, it is important to know the accuracy of and biases in genetic connectivity estimators when connectivity has declined recently. Using simulated data, we investigated the accuracy and bias of 2 common estimators of migration (movement of individuals among populations) rate. We focused on the timing of the connectivity change and the magnitude of that change on the estimates of migration by using a coalescent-based method (Migrate-n) and a disequilibrium-based method (BayesAss). Contrary to expectations, when historically high connectivity had declined recently: (i) both methods over-estimated recent migration rates; (ii) the coalescent-based method (Migrate-n) provided better estimates of recent migration rate than the disequilibrium-based method (BayesAss); (iii) the coalescent-based method did not accurately reflect long-term genetic connectivity. Overall, our results highlight the problems with comparing coalescent and disequilibrium estimates to make inferences about the effects of recent landscape change on genetic connectivity among populations. We found that contrasting these 2 estimates to make inferences about genetic-connectivity changes over time could lead to inaccurate conclusions. © 2016 Society for Conservation Biology.

Adapting to a Changing Environment: Modeling the Interaction of Directional Selection and Plasticity.

PubMed

Nunney, Leonard

2016-01-01

Human-induced habitat loss and fragmentation constrains the range of many species, making them unable to respond to climate change by moving. For such species to avoid extinction, they must respond with some combination of phenotypic plasticity and genetic adaptation. Haldane's "cost of natural selection" limits the rate of adaptation, but, although modeling has shown that in very large populations long-term adaptation can be maintained at rates substantially faster than Haldane's suggested limit, maintaining large populations is often an impossibility, so phenotypic plasticity may be crucial in enhancing the long-term survival of small populations. The potential importance of plasticity is in "buying time" for populations subject to directional environmental change: if genotypes can encompass a greater environmental range, then populations can maintain high fitness for a longer period of time. Alternatively, plasticity could be detrimental by lessening the effectiveness of natural selection in promoting genetic adaptation. Here, I modeled a directionally changing environment in which a genotype's adaptive phenotypic plasticity is centered around the environment where its fitness is highest. Plasticity broadens environmental tolerance and, provided it is not too costly, is favored by natural selection. However, a paradoxical result of the individually advantageous spread of plasticity is that, unless the adaptive trait is determined by very few loci, the long-term extinction risk of a population increases. This effect reflects a conflict between the short-term individual benefit of plasticity and a long-term detriment to population persistence, adding to the multiple threats facing small populations under conditions of climate change. © The American Genetic Association. 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Preliminary trial of the effect of general practice based nutritional advice.

PubMed Central

Baron, J A; Gleason, R; Crowe, B; Mann, J I

1990-01-01

Despite formal recommendations for dietary change to reduce the incidence of ischaemic heart disease, the acceptability and effectiveness of the proposed diets have not been well investigated in population based studies. In this preliminary investigation of nutritional advice in a well population, subjects in one group practice were randomized to receive either dietary instruction or simple follow up without instruction. The dietary recommendations were well received, and a substantial proportion of subjects reported altering their diets in accordance with them. There were modest beneficial changes in plasma lipid levels among men. Thus, using general practice as an avenue for promoting dietary change is feasible, and may be effective among men. PMID:2115348

Long-Term Trends and Role of Climate in the Population Dynamics of Eurasian Reindeer

PubMed Central

Horstkotte, Tim; Kaarlejärvi, Elina; Sévêque, Anthony; Stammler, Florian; Olofsson, Johan; Forbes, Bruce C.; Moen, Jon

2016-01-01

Temperature is increasing in Arctic and sub-Arctic regions at a higher rate than anywhere else in the world. The frequency and nature of precipitation events are also predicted to change in the future. These changes in climate are expected, together with increasing human pressures, to have significant impacts on Arctic and sub-Arctic species and ecosystems. Due to the key role that reindeer play in those ecosystems, it is essential to understand how climate will affect the region’s most important species. Our study assesses the role of climate on the dynamics of fourteen Eurasian reindeer (Rangifer tarandus) populations, using for the first time data on reindeer abundance collected over a 70-year period, including both wild and semi-domesticated reindeer, and covering more than half of the species’ total range. We analyzed trends in population dynamics, investigated synchrony among population growth rates, and assessed the effects of climate on population growth rates. Trends in the population dynamics were remarkably heterogeneous. Synchrony was apparent only among some populations and was not correlated with distance among population ranges. Proxies of climate variability mostly failed to explain population growth rates and synchrony. For both wild and semi-domesticated populations, local weather, biotic pressures, loss of habitat and human disturbances appear to have been more important drivers of reindeer population dynamics than climate. In semi-domesticated populations, management strategies may have masked the effects of climate. Conservation efforts should aim to mitigate human disturbances, which could exacerbate the potentially negative effects of climate change on reindeer populations in the future. Special protection and support should be granted to those semi-domesticated populations that suffered the most because of the collapse of the Soviet Union, in order to protect the livelihood of indigenous peoples that depend on the species, and the multi-faceted role that reindeer exert in Arctic ecosystems. PMID:27362499

Long-Term Trends and Role of Climate in the Population Dynamics of Eurasian Reindeer.

PubMed

Uboni, Alessia; Horstkotte, Tim; Kaarlejärvi, Elina; Sévêque, Anthony; Stammler, Florian; Olofsson, Johan; Forbes, Bruce C; Moen, Jon

2016-01-01

Temperature is increasing in Arctic and sub-Arctic regions at a higher rate than anywhere else in the world. The frequency and nature of precipitation events are also predicted to change in the future. These changes in climate are expected, together with increasing human pressures, to have significant impacts on Arctic and sub-Arctic species and ecosystems. Due to the key role that reindeer play in those ecosystems, it is essential to understand how climate will affect the region's most important species. Our study assesses the role of climate on the dynamics of fourteen Eurasian reindeer (Rangifer tarandus) populations, using for the first time data on reindeer abundance collected over a 70-year period, including both wild and semi-domesticated reindeer, and covering more than half of the species' total range. We analyzed trends in population dynamics, investigated synchrony among population growth rates, and assessed the effects of climate on population growth rates. Trends in the population dynamics were remarkably heterogeneous. Synchrony was apparent only among some populations and was not correlated with distance among population ranges. Proxies of climate variability mostly failed to explain population growth rates and synchrony. For both wild and semi-domesticated populations, local weather, biotic pressures, loss of habitat and human disturbances appear to have been more important drivers of reindeer population dynamics than climate. In semi-domesticated populations, management strategies may have masked the effects of climate. Conservation efforts should aim to mitigate human disturbances, which could exacerbate the potentially negative effects of climate change on reindeer populations in the future. Special protection and support should be granted to those semi-domesticated populations that suffered the most because of the collapse of the Soviet Union, in order to protect the livelihood of indigenous peoples that depend on the species, and the multi-faceted role that reindeer exert in Arctic ecosystems.

The Impacts of Highway Expansion on Population Change: An Integrated Spatial Approach

ERIC Educational Resources Information Center

Chi, Guangqing

2010-01-01

The effects of highways on transforming human society and promoting population change have been investigated in several disciplines, including geography, sociology, economics, and planning. Currently, the primary highway construction activity in the nation is highway expansion; however, this expansion has not been the focus of much of the existing…

Is brood parasitism related to host nestling diet and nutrition?

Treesearch

Zachary S. Ladin; Vincent D' Amico; Deb P. Jaisi; W. Gregory Shriver

2015-01-01

Food and nutrient limitation can have negative effects on survival, fecundity, and lifetime fitness of individuals, which can ultimately limit populations. Changes in trophic dynamics and diet patterns, affected by anthropogenic environmental and landscape change, are poorly understood yet may play an important role in population regulation. We determined diets of Wood...

Projections of Water Stress Based on an Ensemble of Socioeconomic Growth and Climate Change Scenarios: A Case Study in Asia.

PubMed

Fant, Charles; Schlosser, C Adam; Gao, Xiang; Strzepek, Kenneth; Reilly, John

2016-01-01

The sustainability of future water resources is of paramount importance and is affected by many factors, including population, wealth and climate. Inherent in current methods to estimate these factors in the future is the uncertainty of their prediction. In this study, we integrate a large ensemble of scenarios--internally consistent across economics, emissions, climate, and population--to develop a risk portfolio of water stress over a large portion of Asia that includes China, India, and Mainland Southeast Asia in a future with unconstrained emissions. We isolate the effects of socioeconomic growth from the effects of climate change in order to identify the primary drivers of stress on water resources. We find that water needs related to socioeconomic changes, which are currently small, are likely to increase considerably in the future, often overshadowing the effect of climate change on levels of water stress. As a result, there is a high risk of severe water stress in densely populated watersheds by 2050, compared to recent history. There is strong evidence to suggest that, in the absence of autonomous adaptation or societal response, a much larger portion of the region's population will live in water-stressed regions in the near future. Tools and studies such as these can effectively investigate large-scale system sensitivities and can be useful in engaging and informing decision makers.

Quantifying climate change impacts emphasises the importance of managing regional threats in the endangered Yellow-eyed penguin.

PubMed

Mattern, Thomas; Meyer, Stefan; Ellenberg, Ursula; Houston, David M; Darby, John T; Young, Melanie; van Heezik, Yolanda; Seddon, Philip J

2017-01-01

Climate change is a global issue with effects that are difficult to manage at a regional scale. Yet more often than not climate factors are just some of multiple stressors affecting species on a population level. Non-climatic factors-especially those of anthropogenic origins-may play equally important roles with regard to impacts on species and are often more feasible to address. Here we assess the influence of climate change on population trends of the endangered Yellow-eyed penguin ( Megadyptes antipodes ) over the last 30 years, using a Bayesian model. Sea surface temperature (SST) proved to be the dominating factor influencing survival of both adult birds and fledglings. Increasing SST since the mid-1990s was accompanied by a reduction in survival rates and population decline. The population model showed that 33% of the variation in population numbers could be explained by SST alone, significantly increasing pressure on the penguin population. Consequently, the population becomes less resilient to non-climate related impacts, such as fisheries interactions, habitat degradation and human disturbance. However, the extent of the contribution of these factors to declining population trends is extremely difficult to assess principally due to the absence of quantifiable data, creating a discussion bias towards climate variables, and effectively distracting from non-climate factors that can be managed on a regional scale to ensure the viability of the population.

Interactions between demography and environmental effects are important determinants of population dynamics

PubMed Central

Gamelon, Marlène; Grøtan, Vidar; Nilsson, Anna L. K.; Engen, Steinar; Hurrell, James W.; Jerstad, Kurt; Phillips, Adam S.; Røstad, Ole W.; Slagsvold, Tore; Walseng, Bjørn; Stenseth, Nils C.; Sæther, Bernt-Erik

2017-01-01

Climate change will affect the population dynamics of many species, yet the consequences for the long-term persistence of populations are poorly understood. A major reason for this is that density-dependent feedback effects caused by fluctuations in population size are considered independent of stochastic variation in the environment. We show that an interplay between winter temperature and population density can influence the persistence of a small passerine population under global warming. Although warmer winters favor an increased mean population size, density-dependent feedback can cause the local population to be less buffered against occasional poor environmental conditions (cold winters). This shows that it is essential to go beyond the population size and explore climate effects on the full dynamics to elaborate targeted management actions. PMID:28164157

Shifting species interactions in terrestrial dryland ecosystems under altered water availability and climate change

USGS Publications Warehouse

McCluney, Kevin E.; Belnap, Jayne; Collins, Scott L.; González, Angélica L.; Hagen, Elizabeth M.; Holland, J. Nathaniel; Kotler, Burt P.; Maestre, Fernando T.; Smith, Stanley D.; Wolf, Blair O.

2012-01-01

Species interactions play key roles in linking the responses of populations, communities, and ecosystems to environmental change. For instance, species interactions are an important determinant of the complexity of changes in trophic biomass with variation in resources. Water resources are a major driver of terrestrial ecology and climate change is expected to greatly alter the distribution of this critical resource. While previous studies have documented strong effects of global environmental change on species interactions in general, responses can vary from region to region. Dryland ecosystems occupy more than one-third of the Earth's land mass, are greatly affected by changes in water availability, and are predicted to be hotspots of climate change. Thus, it is imperative to understand the effects of environmental change on these globally significant ecosystems. Here, we review studies of the responses of population-level plant-plant, plant-herbivore, and predator-prey interactions to changes in water availability in dryland environments in order to develop new hypotheses and predictions to guide future research. To help explain patterns of interaction outcomes, we developed a conceptual model that views interaction outcomes as shifting between (1) competition and facilitation (plant-plant), (2) herbivory, neutralism, or mutualism (plant-herbivore), or (3) neutralism and predation (predator-prey), as water availability crosses physiological, behavioural, or population-density thresholds. We link our conceptual model to hypothetical scenarios of current and future water availability to make testable predictions about the influence of changes in water availability on species interactions. We also examine potential implications of our conceptual model for the relative importance of top-down effects and the linearity of patterns of change in trophic biomass with changes in water availability. Finally, we highlight key research needs and some possible broader impacts of our findings. Overall, we hope to stimulate and guide future research that links changes in water availability to patterns of species interactions and the dynamics of populations and communities in dryland ecosystems.

Potential Environmental and Ecological Effects of Global Climate Change on Venomous Terrestrial Species in the Wilderness.

PubMed

Needleman, Robert K; Neylan, Isabelle P; Erickson, Timothy

2018-06-01

Climate change has been scientifically documented, and its effects on wildlife have been prognosticated. We sought to predict the overall impact of climate change on venomous terrestrial species. We hypothesize that given the close relationship between terrestrial venomous species and climate, a changing global environment may result in increased species migration, geographical redistribution, and longer seasons for envenomation, which would have repercussions on human health. A retrospective analysis of environmental, ecological, and medical literature was performed with a focus on climate change, toxinology, and future modeling specific to venomous terrestrial creatures. Species included venomous reptiles, snakes, arthropods, spiders, and Hymenoptera (ants and bees). Animals that are vectors of hemorrhagic infectious disease (eg, mosquitos, ticks) were excluded. Our review of the literature indicates that changes to climatic norms will have a potentially dramatic effect on terrestrial venomous creatures. Empirical evidence demonstrates that geographic distributions of many species have already shifted due to changing climatic conditions. Given that most terrestrial venomous species are ectotherms closely tied to ambient temperature, and that climate change is shifting temperature zones away from the equator, further significant distribution and population changes should be anticipated. For those species able to migrate to match the changing temperatures, new geographical locations may open. For those species with limited distribution capabilities, the rate of climate change may accelerate faster than species can adapt, causing population declines. Specifically, poisonous snakes and spiders will likely maintain their population numbers but will shift their geographic distribution to traditionally temperate zones more often inhabited by humans. Fire ants and Africanized honey bees are expected to have an expanded range distribution due to predicted warming trends. Human encounters with these types of creatures are likely to increase, resulting in potential human morbidity and mortality. Temperature extremes and changes to climatic norms may have a dramatic effect on venomous terrestrial species. As climate change affects the distribution, populations, and life histories of these organisms, the chance of encounters could be altered, thus affecting human health and the survivability of these creatures. Copyright © 2017 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

Climate change alters reproductive isolation and potential gene flow in an annual plant.

PubMed

Franks, Steven J; Weis, Arthur E

2009-11-01

Climate change will likely cause evolution due not only to selection but also to changes in reproductive isolation within and among populations. We examined the effects of a natural drought on the timing of flowering in two populations of Brassica rapa and the consequences for predicted reproductive isolation and potential gene flow. Seeds were collected before and after a 5-year drought in southern California from two populations varying in soil moisture. Lines derived from these seeds were raised in the greenhouse under wet and drought conditions. We found that the natural drought caused changes in reproductive timing and that the changes were greater for plants from the wet than from the dry site. This differential shift caused the populations to become more phenological similar, which should lead to less reproductive isolation and increased gene flow. We estimated a high level of assortative mating by flowering time, which potentially contributed to the rapid evolution of phenological traits following the drought. Estimates of assortative mating were higher for the wet site population, and assortative mating was reduced following the drought. This study shows that climate change can potentially alter gene flow and reproductive isolation within and among populations, strongly influencing evolution.

Microgeographic and temporal genetic variation in populations of the bluetongue virus vector Culicoides variipennis (Diptera: Ceratopogonidae).

PubMed

Tabachnick, W J

1992-05-01

Seven Colorado populations of the bluetongue virus vector Culicoides varipennis (Coquillett) were analyzed for genetic variation at 19-21 isozyme loci. Permanent populations, which overwinter as larvae, showed little temporal genetic change at 19 loci. PGD and MDH showed seasonal changes in gene frequencies, attributable to selection at two permanent populations. Two temporary populations showed low heterozygosity compared with permanent populations. Independent estimates of gene flow, calculated using FST and the private allele method, were Nm* = 2.15 and 6.95, respectively. Colorado C. variipennis permanent populations showed high levels of gene flow which prevented significant genetic differentiation due to genetic drift. Temporary populations showed significant gene frequency differences from nearby permanent populations due to the "founder effect" associated with chance colonization.

Estimating multi-factor cumulative watershed effects on fish populations with an individual-based model

Treesearch

Bret C. Harvey; Steven F. Railsback

2007-01-01

While the concept of cumulative effects is prominent in legislation governing environmental management, the ability to estimate cumulative effects remains limited. One reason for this limitation is that important natural resources such as fish populations may exhibit complex responses to changes in environmental conditions, particularly to alteration of multiple...

Forecasting effects of climate change on Great Lakes fisheries: models that link habitat supply to population dynamics can help

USGS Publications Warehouse

Jones, Michael L.; Shuter, Brian J.; Zhao, Yingming; Stockwell, Jason D.

2006-01-01

Future changes to climate in the Great Lakes may have important consequences for fisheries. Evidence suggests that Great Lakes air and water temperatures have risen and the duration of ice cover has lessened during the past century. Global circulation models (GCMs) suggest future warming and increases in precipitation in the region. We present new evidence that water temperatures have risen in Lake Erie, particularly during summer and winter in the period 1965–2000. GCM forecasts coupled with physical models suggest lower annual runoff, less ice cover, and lower lake levels in the future, but the certainty of these forecasts is low. Assessment of the likely effects of climate change on fish stocks will require an integrative approach that considers several components of habitat rather than water temperature alone. We recommend using mechanistic models that couple habitat conditions to population demographics to explore integrated effects of climate-caused habitat change and illustrate this approach with a model for Lake Erie walleye (Sander vitreum). We show that the combined effect on walleye populations of plausible changes in temperature, river hydrology, lake levels, and light penetration can be quite different from that which would be expected based on consideration of only a single factor.

Study of radiation effects on mammalian cells in vitro

NASA Technical Reports Server (NTRS)

Sinclair, W. K.

1968-01-01

Radiation effect on single cells and cell populations of Chinese hamster lung tissue is studied in vitro. The rate and position as the cell progresses through the generation cycle shows division delay, changes in some biochemical processes in the cell, chromosomal changes, colony size changes, and loss of reproductive capacity.

COMBINED AND INTERACTIVE EFFECTS OF GLOBAL CLIMATE CHANGE AND TOXICANTS ON POPULATIONS AND COMMUNITIES

PubMed Central

Moe, S Jannicke; De Schamphelaere, Karel; Clements, William H; Sorensen, Mary T; Van den Brink, Paul J; Liess, Matthias

2013-01-01

Increased temperature and other environmental effects of global climate change (GCC) have documented impacts on many species (e.g., polar bears, amphibians, coral reefs) as well as on ecosystem processes and species interactions (e.g., the timing of predator–prey interactions). A challenge for ecotoxicologists is to predict how joint effects of climatic stress and toxicants measured at the individual level (e.g., reduced survival and reproduction) will be manifested at the population level (e.g., population growth rate, extinction risk) and community level (e.g., species richness, food-web structure). The authors discuss how population- and community-level responses to toxicants under GCC are likely to be influenced by various ecological mechanisms. Stress due to GCC may reduce the potential for resistance to and recovery from toxicant exposure. Long-term toxicant exposure can result in acquired tolerance to this stressor at the population or community level, but an associated cost of tolerance may be the reduced potential for tolerance to subsequent climatic stress (or vice versa). Moreover, GCC can induce large-scale shifts in community composition, which may affect the vulnerability of communities to other stressors. Ecological modeling based on species traits (representing life-history traits, population vulnerability, sensitivity to toxicants, and sensitivity to climate change) can be a promising approach for predicting combined impacts of GCC and toxicants on populations and communities. Environ. Toxicol. Chem. 2013;32:49–61. © 2012 SETAC PMID:23147390

The population approach to falls injury prevention in older people: findings of a two community trial

PubMed Central

2010-01-01

Background There is a sound rationale for the population-based approach to falls injury prevention but there is currently insufficient evidence to advise governments and communities on how they can use population-based strategies to achieve desired reductions in the burden of falls-related injury. The aim of the study was to quantify the effectiveness of a streamlined (and thus potentially sustainable and cost-effective), population-based, multi-factorial falls injury prevention program for people over 60 years of age. Methods Population-based falls-prevention interventions were conducted at two geographically-defined and separate Australian sites: Wide Bay, Queensland, and Northern Rivers, NSW. Changes in the prevalence of key risk factors and changes in rates of injury outcomes within each community were compared before and after program implementation and changes in rates of injury outcomes in each community were also compared with the rates in their respective States. Results The interventions in neither community substantially decreased the rate of falls-related injury among people aged 60 years or older, although there was some evidence of reductions in occurrence of multiple falls reported by women. In addition, there was some indication of improvements in fall-related risk factors, but the magnitudes were generally modest. Conclusions The evidence suggests that low intensity population-based falls prevention programs may not be as effective as those that are intensively implemented. PMID:20167124

Using HMOs to serve the Medicaid population: what are the effects on utilization and does the type of HMO matter?

PubMed

Herring, Bradley; Adams, E Kathleen

2011-04-01

States have increasingly used Health Maintenance Organizations (HMOs) to provide medical services to the Medicaid population. However, the effects of these initiatives on total health-care expenses, the mix of utilization, and access to care remain unclear. We examine the effect of changes in Medicaid HMO penetration between 1996 and 2002 on these outcomes using data for the nonelderly Medicaid population in the Community Tracking Study's Household Survey. We develop market-level measures of Medicaid HMO penetration from CMS and InterStudy data, distinguish whether the HMOs specialize in serving the Medicaid population, and use a market fixed-effects model to focus on changes in HMO penetration rates over time. Although limited by imprecise estimates, we find some evidence that utilization and access are related to the market penetration rates of commercial and Medicaid-dominant HMOs, but the pattern of results we observe does not appear to be consistent with welfare improvements. Copyright © 2010 John Wiley & Sons, Ltd.

Synergistic effects of climate change and harvest on extinction risk of American ginseng.

PubMed

Souther, Sara; McGraw, James B

Over the next century, the conservation of biodiversity will depend not only on our ability to understand the effect of climate change, but also on our capacity to predict how other factors interact with climate change to influence species viability. We used American ginseng (Panax quinquefolius L.), the United States' premier wild-harvested medicinal, as a model system to ask whether the effect of harvest on extinction risk depends on changing climatic conditions. We performed stochastic projections of viability response to an increase in maximum growing-season temperature of 1°C over the next 70 years by sampling matrices from long-term demographic studies of 12 populations (representing 75 population-years of data). In simulations that included harvest and climate change, extinction risk at the median population size (N = 140) was 65%, far exceeding the additive effects of the two factors (extinction risk = 8% and 6% for harvest and climate change, respectively; quasi-extinction threshold = 20). We performed a life table response experiment (LTRE) to determine underlying causes of the effect of warming and harvest on deterministic λ (λd). Together, these factors decreased λd values primarily by reducing growth of juvenile and small adult plants to the large-adult stage, as well as decreasing stasis of the juveniles and large adults. The interaction observed in stochastic model results followed from a nonlinear increase in extinction risk as the combined impact of harvest and warming consistently reduced λ values below the demographic tipping point of λ = 1. While further research is needed to create specific recommendations, these findings indicate that ginseng harvest regulations should be revised to account for changing climate. Given the possibility of nonlinear response like that reported here, pre-emptive adaptation of management strategies may increase efficacy of biodiversity conservation by allowing behavior modification prior to precipitous population decline.

Effect of Thermospheric Neutral Density upon Inner Trapped-belt Proton Flux

NASA Technical Reports Server (NTRS)

Wilson, Thomas L.; Lodhi, M. A. K.; Diaz, Abel B.

2007-01-01

We wish to point out that a secular change in the Earth's atmospheric neutral density alters charged-particle lifetime in the inner trapped radiation belts, in addition to the changes recently reported as produced by greenhouse gases. Heretofore, changes in neutral density have been of interest primarily because of their effect on the orbital drag of satellites. We extend this to include the orbital lifetime of charged particles in the lower radiation belts. It is known that the charged-belt population is coupled to the neutral density of the atmosphere through changes induced by solar activity, an effect produced by multiple scattering off neutral and ionized atoms along with ionization loss in the thermosphere where charged and neutral populations interact. It will be shown here that trapped-belt flux J is bivariant in energy E and thermospheric neutral density , as J(E,rho). One can conclude that proton lifetimes in these belts are also directly affected by secular changes in the neutral species populating the Earth s thermosphere. This result is a consequence of an intrinsic property of charged-particle flux, that flux is not merely a function of E but is dependent upon density rho when a background of neutrals is present.

Regional climatic warming drives long-term community changes of British marine fish.

PubMed Central

Genner, Martin J.; Sims, David W.; Wearmouth, Victoria J.; Southall, Emily J.; Southward, Alan J.; Henderson, Peter A.; Hawkins, Stephen J.

2004-01-01

Climatic change has been implicated as the cause of abundance fluctuations in marine fish populations worldwide, but the effects on whole communities are poorly understood. We examined the effects of regional climatic change on two fish assemblages using independent datasets from inshore marine (English Channel, 1913-2002) and estuarine environments (Bristol Channel, 1981-2001). Our results show that climatic change has had dramatic effects on community composition. Each assemblage contained a subset of dominant species whose abundances were strongly linked to annual mean sea-surface temperature. Species' latitudinal ranges were not good predictors of species-level responses, however, and the same species did not show congruent trends between sites. This suggests that within a region, populations of the same species may respond differently to climatic change, possibly owing to additional local environmental determinants, interspecific ecological interactions and dispersal capacity. This will make species-level responses difficult to predict within geographically differentiated communities. PMID:15156925

Comparing the effects of food restriction and overeating on brain reward systems

PubMed Central

Avena, Nicole M.; Murray, Susan; Gold, Mark S.

2014-01-01

Both caloric restriction and overeating have been shown to affect neural processes associated with reinforcement. Both preclinical and some clinical studies have provided evidence that food restriction may increase reward sensitivity, and while there are mixed findings regarding the effects of overeating on reward sensitivity, there is strong evidence linking this behavior with changes in reward-related brain regions. Evidence of these changes comes in part from findings that show that such eating patterns are associated with increased drug use. The data discussed here regarding the differential effects of various eating patterns on reward systems may be particularly relevant to the aging population, as this population has been shown to exhibit altered reward sensitivity and decreased caloric consumption. Moreover, members of this population appear to be increasingly affected by the current obesity epidemic. Food, like alcohol or drugs, can stimulate its own consumption and produce similar neurochemical changes in the brain. Age-related loss of appetite, decreased eating, and caloric restriction are hypothesized to be associated with changes in the prevalence of substance misuse, abuse, and dependence seen in this cohort. PMID:23535488

Contrasting effects of climate change in continental vs. oceanic environments on population persistence and microevolution of Atlantic salmon.

PubMed

Piou, Cyril; Prévost, Etienne

2013-03-01

Facing climate change (CC), species are prone to multiple modifications in their environment that can lead to extinction, migration or adaptation. Identifying the role and interplay of different potential stressors becomes a key question. Anadromous fishes will be exposed to both river and oceanic habitat changes. For Atlantic salmon, the river water temperature, river flow and oceanic growth conditions appear as three main stressing factors. They could act on population dynamics or as selective forces on life-history pathways. Using an individual-based demo-genetic model, we assessed the effects of these factors (1) to compare risks of extinction resulting from CC in river and ocean, and (2) to assess CC effects on life-history pathways including the evolution of underlying genetic control of phenotypic plasticity. We focused on Atlantic salmon populations from Southern Europe for a time horizon of three decades. We showed that CC in river alone should not lead to extinction of Southern European salmon populations. In contrast, the reduced oceanic growth appeared as a significant threat for population persistence. An increase in river flow amplitude increased the risk of local extinction in synergy with the oceanic effects, but river temperature rise reduced this risk. In terms of life-history modifications, the reduced oceanic growth increased the age of return of individuals through plastic and genetic responses. The river temperature rise increased the proportion of sexually mature parr, but the genetic evolution of the maturation threshold lowered the maturation rate of male parr. This was identified as a case of environmentally driven plastic response that masked an underlying evolutionary response of plasticity going in the opposite direction. We concluded that to counteract oceanic effects, river flow management represented the sole potential force to reduce the extinction probability of Atlantic salmon populations in Southern Europe, although this might not impede changes in migration life history. © 2012 Blackwell Publishing Ltd.

Climate warming: a loss of variation in populations can accompany reproductive shifts.

PubMed

Massot, Manuel; Legendre, Stéphane; Fédérici, Pierre; Clobert, Jean

2017-09-01

The most documented response of organisms to climate warming is a change in the average timing of seasonal activities (phenology). Although we know that these average changes can differ among species and populations, we do not know whether climate warming impacts within-population variation in phenology. Using data from five study sites collected during a 13-year survey, we found that the increase in spring temperatures is associated with a reproductive advance of 10 days in natural populations of common lizards (Zootoca vivipara). Interestingly, we show a correlated loss of variation in reproductive dates within populations. As illustrated by a model, this shortening of the reproductive period can have significant negative effects on population dynamics. Consequently, we encourage tests in other species to assess the generality of decreased variation in phenological responses to climate change. © 2017 The Authors Ecology Letters published by CNRS and John Wiley & Sons Ltd.

Hormonally mediated maternal effects, individual strategy and global change

PubMed Central

Meylan, Sandrine; Miles, Donald B.; Clobert, Jean

2012-01-01

A challenge to ecologists and evolutionary biologists is predicting organismal responses to the anticipated changes to global ecosystems through climate change. Most evidence suggests that short-term global change may involve increasing occurrences of extreme events, therefore the immediate response of individuals will be determined by physiological capacities and life-history adaptations to cope with extreme environmental conditions. Here, we consider the role of hormones and maternal effects in determining the persistence of species in altered environments. Hormones, specifically steroids, are critical for patterning the behaviour and morphology of parents and their offspring. Hence, steroids have a pervasive influence on multiple aspects of the offspring phenotype over its lifespan. Stress hormones, e.g. glucocorticoids, modulate and perturb phenotypes both early in development and later into adulthood. Females exposed to abiotic stressors during reproduction may alter the phenotypes by manipulation of hormones to the embryos. Thus, hormone-mediated maternal effects, which generate phenotypic plasticity, may be one avenue for coping with global change. Variation in exposure to hormones during development influences both the propensity to disperse, which alters metapopulation dynamics, and population dynamics, by affecting either recruitment to the population or subsequent life-history characteristics of the offspring. We suggest that hormones may be an informative index to the potential for populations to adapt to changing environments. PMID:22566673

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

Treesearch

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...

Predicting Effects of Coastal Acidification on Marine Bivalve ...

EPA Pesticide Factsheets

The partial pressure of carbon dioxide (pCO2) is increasing in the oceans and causing changes in seawater pH commonly described as ocean or coastal acidification. It is now well-established that, when reproduced in laboratory experiments, these increases in pCO2 can reduce survival and growth of early life stage bivalves. However, the effects that these impairments would have on whole populations of bivalves are unknown. In this study, these laboratory responses were incorporated into field-parameterized population models to assess population-level sensitivities to acidification for two northeast bivalve species with different life histories: Mercenaria mercenaria (hard clam) and Argopecten irradians (bay scallop). The resulting models permitted translation of laboratory pCO2 response functions into population-level responses to examine population sensitivity to future pCO2 changes. Preliminary results from our models indicate that if the current M. mercenaria negative population growth rate was attributed to the effects of pCO2 on early life stages, the population would decline at a rate of 50% per ten years at 420 microatmospheres (µatm) pCO2. If the current population growth rate was attributed to other additive factors (e.g., harvest, harmful algal blooms), M. mercenaria populations were predicted to decline at a rate of 50% per ten years at the preliminary estimate of 1010 µatm pCO2. The estimated population growth rate was positive for A. irradians,

Health system productivity change in Zambia: A focus on the child health services.

PubMed

Achoki, Tom; Kinfu, Yohannes; Masiye, Felix; Frederix, Geert W J; Hovels, Anke; Leufkens, Hubert G

2017-02-01

Efficiency and productivity improvement have become central in global health debates. In this study, we explored productivity change, particularly the contribution of technological progress and efficiency gains associated with improvements in child survival in Zambia (population 15 million). Productivity was measured by applying the Malmquist productivity index on district-level panel data. The effect of socioeconomic factors was further analyzed by applying an ordinary least squares regression technique. During 2004-2009, overall productivity in Zambia increased by 5.0 per cent, a change largely attributed to technological progress rather than efficiency gains. Within-country productivity comparisons revealed wide heterogeneity in favor of more urbanized and densely populated districts. Improved cooking methods, improved sanitation, and better educated populations tended to improve productive gains, whereas larger household size had an adverse effect. Addressing such district-level factors and ensuring efficient delivery and optimal application of existing health technologies offer a practical pathway for further improving population health.

The Influence of Individual Variability on Zooplankton Population Dynamics under Different Environmental Conditions

NASA Astrophysics Data System (ADS)

Bi, R.; Liu, H.

2016-02-01

Understanding how biological components respond to environmental changes could be insightful to predict ecosystem trajectories under different climate scenarios. Zooplankton are key components of marine ecosystems and changes in their dynamics could have major impact on ecosystem structure. We developed an individual-based model of a common coastal calanoid copepod Acartia tonsa to examine how environmental factors affect zooplankton population dynamics and explore the role of individual variability in sustaining population under various environmental conditions consisting of temperature, food concentration and salinity. Total abundance, egg production and proportion of survival were used to measure population success. Results suggested population benefits from high level of individual variability under extreme environmental conditions including unfavorable temperature, salinity, as well as low food concentration, and selection on fast-growers becomes stronger with increasing individual variability and increasing environmental stress. Multiple regression analysis showed that temperature, food concentration, salinity and individual variability have significant effects on survival of A. tonsa population. These results suggest that environmental factors have great influence on zooplankton population, and individual variability has important implications for population survivability under unfavorable conditions. Given that marine ecosystems are at risk from drastic environmental changes, understanding how individual variability sustains populations could increase our capability to predict population dynamics in a changing environment.

Visualizing diurnal population change in urban areas for emergency management.

PubMed

Kobayashi, Tetsuo; Medina, Richard M; Cova, Thomas J

2011-01-01

There is an increasing need for a quick, simple method to represent diurnal population change in metropolitan areas for effective emergency management and risk analysis. Many geographic studies rely on decennial U.S. Census data that assume that urban populations are static in space and time. This has obvious limitations in the context of dynamic geographic problems. The U.S. Department of Transportation publishes population data at the transportation analysis zone level in fifteen-minute increments. This level of spatial and temporal detail allows for improved dynamic population modeling. This article presents a methodology for visualizing and analyzing diurnal population change for metropolitan areas based on this readily available data. Areal interpolation within a geographic information system is used to create twenty-four (one per hour) population surfaces for the larger metropolitan area of Salt Lake County, Utah. The resulting surfaces represent diurnal population change for an average workday and are easily combined to produce an animation that illustrates population dynamics throughout the day. A case study of using the method to visualize population distributions in an emergency management context is provided using two scenarios: a chemical release and a dirty bomb in Salt Lake County. This methodology can be used to address a wide variety of problems in emergency management.

Climate change, human communities, and forests in rural, urban, and wildland-urban interface environments

Treesearch

David N. Wear; Linda A. Joyce

2012-01-01

Human concerns about the effects of climate change on forests are related to the values that forests provide to human populations, that is, to the effects on ecosystem services derived from forests. Service values include the consumption of timber products, the regulation of climate and water quality, and aesthetic and spiritual values. Effects of climate change on...

Expansion of corals on temperate reefs: direct and indirect effects of marine heatwaves

NASA Astrophysics Data System (ADS)

Tuckett, C. A.; de Bettignies, T.; Fromont, J.; Wernberg, T.

2017-09-01

Globally, many temperate marine communities have experienced significant temperature increases over recent decades in the form of gradual warming and heatwaves. As a result, these communities are shifting towards increasingly subtropical and tropical species compositions. Expanding coral populations have been reported from several temperate reef ecosystems along warming coastlines; these changes have been attributed to direct effects of gradual warming over decades. In contrast, increases in coral populations following shorter-term extreme warming events have rarely been documented. In this study, we compared coral populations on 17 temperate reefs in Western Australia before (2005/06) and after (2013) multiple marine heatwaves (2010-2012) affected the entire coastline. We hypothesised that coral communities would expand and change as a consequence of increasing local populations and recruitment of warm-affinity species. We found differences in coral community structure over time, driven primarily by a fourfold increase of one local species, Plesiastrea versipora, rather than recruitment of warm-affinity species. Coral populations became strongly dominated by small size classes, indicative of recent increased recruitment or recruit survival. These changes were likely facilitated by competitive release of corals from dominant temperate seaweeds, which perished during the heatwaves, rather than driven by direct temperature effects. Overall, as corals are inherently warm-water taxa not commonly associated with seaweed-dominated temperate reefs, these findings are consistent with a net tropicalisation. Our study draws attention to processes other than gradual warming that also influence the trajectory of temperate reefs in a changing ocean.

Seasonal Population Dynamics of Megacopta cribraria (Hemiptera: Plataspidae) in Kudzu and Soybean, and Implication for Insecticidal Management in Soybean.

PubMed

Blount, J L; Roberts, P M; Toews, M D; Gardner, W A; Buntin, G D; Davis, J W; All, J N

2017-02-01

Megacopta cribraria (F.), an invasive species introduced from Asia in 2009, is now prolific in the southeastern United States. Megacopta cribraria develops primarily on kudzu and soybean completing two generations. It is not well understood how this economic pest is affected by changes in geographic distribution in the United States or how population levels have changed since its establishment. The effect of insecticide application timing on field populations of M. cribraria is not well documented. These studies seek to understand how population dynamics of M. cribraria vary with geographic regions in Georgia. Effect of application timing on populations throughout the growing season was also examined. Weekly from 2012 to 2013, all life stages were enumerated from kudzu and soybean environments at several locations throughout Georgia from sweeps samples and flight intercept captures. Coordinates were recorded for locations, and classified as belonging to the Piedmont or Coastal Plain region of the state. Single spray trials were conducted from 2011-2014, and applications were made to soybean at intervals throughout the season. From 2012 to 2015, two kudzu patches near Griffin, GA, were monitored to detect population changes. Differences in population dynamics from locations around the state were found, but no clear effect of latitude, longitude, or region was observed. Insecticide applications applied in July suppressed nymph populations significantly better than treatments made earlier or later. Megacopta cribraria populations declined in 2014 and 2015 compared with 2012 and 2013. These studies provide the critical information for M. cribraria management in soybean in the southeastern United States. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

EFFECTS OF A HIGHLY-CONTAMINATED URBAN HARBOR ON AN ESTUARINE FISH SPECIES: ADAPTIVE CHANGES AT SPECIFIC LOCI

EPA Science Inventory

Fundulus heteroclitus populations indigenous to certain highly contaminated sites demonstrate an inherited tolerance to the toxic effects of local chemical contaminants. Our initial studies examining populations of F. heterclitus indigenous to a PCB-contaminated Superfund site at...

Worldwide status of burbot and conservation measures

USGS Publications Warehouse

Stapanian, Martin A.; Paragamian, Vaughn L.; Madenjian, Charles P.; Jackson, James R.; Lappalainen, Jyrki; Evenson, Matthew J.; Neufeld, Matthew D.

2010-01-01

Although burbot (Lota lota Gadidae) are widespread and abundant throughout much of their natural range, there are many populations that have been extirpated, endangered or are in serious decline. Due in part to the species’ lack of popularity as a game and commercial fish, few regions consider burbot in management plans. We review the worldwide population status of burbot and synthesize reasons why some burbot populations are endangered or declining, some burbot populations have recovered and some burbot populations do not recover despite management measures. Burbot have been extirpated in much of Western Europe and the United Kingdom and are threatened or endangered in much of North America and Eurasia. Pollution and habitat change, particularly the effects of dams, appear to be the main causes for declines in riverine burbot populations. Pollution and the adverse effects of invasive species appear to be the main reasons for declines in lacustrine populations. Warmer water temperatures, due either to discharge from dams or climate change, have been noted in declining burbot populations at the southern extent of their range. Currently, fishing pressure does not appear to be limiting burbot populations world-wide. We suggest mitigation measures for burbot population recovery, particularly those impacted by dams and invasive species.

Natural amenities and rural population migration: a technical document supporting the Forest Service 2010 RPA Assessment

Treesearch

H. Ken Cordell; Vahé Heboyan; Florence Santos; John C. Bergstrom

2011-01-01

Research has suggested that significant relationships exist between rural population change and natural amenities. Thus, understanding and predicting domestic migration trends as a function of changes in natural amenities is important for effective regional growth and development policies and strategies. In this study, we first estimated an econometric model which...

Whitebark pine, population density, and home-range size of grizzly bears in the greater Yellowstone ecosystem

USGS Publications Warehouse

Bjornlie, Daniel D.; van Manen, Frank T.; Ebinger, Michael R.; Haroldson, Mark A.; Thompson, Daniel J.; Costello, Cecily M.

2014-01-01

Changes in life history traits of species can be an important indicator of potential factors influencing populations. For grizzly bears (Ursus arctos) in the Greater Yellowstone Ecosystem (GYE), recent decline of whitebark pine (WBP; Pinus albicaulis), an important fall food resource, has been paired with a slowing of population growth following two decades of robust population increase. These observations have raised questions whether resource decline or density-dependent processes may be associated with changes in population growth. Distinguishing these effects based on changes in demographic rates can be difficult. However, unlike the parallel demographic responses expected from both decreasing food availability and increasing population density, we hypothesized opposing behavioral responses of grizzly bears with regard to changes in home-range size. We used the dynamic changes in food resources and population density of grizzly bears as a natural experiment to examine hypotheses regarding these potentially competing influences on grizzly bear home-range size. We found that home-range size did not increase during the period of whitebark pine decline and was not related to proportion of whitebark pine in home ranges. However, female home-range size was negatively associated with an index of population density. Our data indicate that home-range size of grizzly bears in the GYE is not associated with availability of WBP, and, for female grizzly bears, increasing population density may constrain home-range size.

Whitebark Pine, Population Density, and Home-Range Size of Grizzly Bears in the Greater Yellowstone Ecosystem

PubMed Central

Bjornlie, Daniel D.; Van Manen, Frank T.; Ebinger, Michael R.; Haroldson, Mark A.; Thompson, Daniel J.; Costello, Cecily M.

2014-01-01

Changes in life history traits of species can be an important indicator of potential factors influencing populations. For grizzly bears (Ursus arctos) in the Greater Yellowstone Ecosystem (GYE), recent decline of whitebark pine (WBP; Pinus albicaulis), an important fall food resource, has been paired with a slowing of population growth following two decades of robust population increase. These observations have raised questions whether resource decline or density-dependent processes may be associated with changes in population growth. Distinguishing these effects based on changes in demographic rates can be difficult. However, unlike the parallel demographic responses expected from both decreasing food availability and increasing population density, we hypothesized opposing behavioral responses of grizzly bears with regard to changes in home-range size. We used the dynamic changes in food resources and population density of grizzly bears as a natural experiment to examine hypotheses regarding these potentially competing influences on grizzly bear home-range size. We found that home-range size did not increase during the period of whitebark pine decline and was not related to proportion of whitebark pine in home ranges. However, female home-range size was negatively associated with an index of population density. Our data indicate that home-range size of grizzly bears in the GYE is not associated with availability of WBP, and, for female grizzly bears, increasing population density may constrain home-range size. PMID:24520354

Fine-scale genetic response to landscape change in a gliding mammal.

PubMed

Goldingay, Ross L; Harrisson, Katherine A; Taylor, Andrea C; Ball, Tina M; Sharpe, David J; Taylor, Brendan D

2013-01-01

Understanding how populations respond to habitat loss is central to conserving biodiversity. Population genetic approaches enable the identification of the symptoms of population disruption in advance of population collapse. However, the spatio-temporal scales at which population disruption occurs are still too poorly known to effectively conserve biodiversity in the face of human-induced landscape change. We employed microsatellite analysis to examine genetic structure and diversity over small spatial (mostly 1-50 km) and temporal scales (20-50 years) in the squirrel glider (Petaurus norfolcensis), a gliding mammal that is commonly subjected to a loss of habitat connectivity. We identified genetically differentiated local populations over distances as little as 3 km and within 30 years of landscape change. Genetically isolated local populations experienced the loss of genetic diversity, and significantly increased mean relatedness, which suggests increased inbreeding. Where tree cover remained, genetic differentiation was less evident. This pattern was repeated in two landscapes located 750 km apart. These results lend support to other recent studies that suggest the loss of habitat connectivity can produce fine-scale population genetic change in a range of taxa. This gives rise to the prediction that many other vertebrates will experience similar genetic changes. Our results suggest the future collapse of local populations of this gliding mammal is likely unless habitat connectivity is maintained or restored. Landscape management must occur on a fine-scale to avert the erosion of biodiversity.

Whitebark pine, population density, and home-range size of grizzly bears in the greater yellowstone ecosystem.

PubMed

Bjornlie, Daniel D; Van Manen, Frank T; Ebinger, Michael R; Haroldson, Mark A; Thompson, Daniel J; Costello, Cecily M

2014-01-01

Changes in life history traits of species can be an important indicator of potential factors influencing populations. For grizzly bears (Ursus arctos) in the Greater Yellowstone Ecosystem (GYE), recent decline of whitebark pine (WBP; Pinus albicaulis), an important fall food resource, has been paired with a slowing of population growth following two decades of robust population increase. These observations have raised questions whether resource decline or density-dependent processes may be associated with changes in population growth. Distinguishing these effects based on changes in demographic rates can be difficult. However, unlike the parallel demographic responses expected from both decreasing food availability and increasing population density, we hypothesized opposing behavioral responses of grizzly bears with regard to changes in home-range size. We used the dynamic changes in food resources and population density of grizzly bears as a natural experiment to examine hypotheses regarding these potentially competing influences on grizzly bear home-range size. We found that home-range size did not increase during the period of whitebark pine decline and was not related to proportion of whitebark pine in home ranges. However, female home-range size was negatively associated with an index of population density. Our data indicate that home-range size of grizzly bears in the GYE is not associated with availability of WBP, and, for female grizzly bears, increasing population density may constrain home-range size.

Release of genetically engineered insects: a framework to identify potential ecological effects

PubMed Central

David, Aaron S; Kaser, Joe M; Morey, Amy C; Roth, Alexander M; Andow, David A

2013-01-01

Genetically engineered (GE) insects have the potential to radically change pest management worldwide. With recent approvals of GE insect releases, there is a need for a synthesized framework to evaluate their potential ecological and evolutionary effects. The effects may occur in two phases: a transitory phase when the focal population changes in density, and a steady state phase when it reaches a new, constant density. We review potential effects of a rapid change in insect density related to population outbreaks, biological control, invasive species, and other GE organisms to identify a comprehensive list of potential ecological and evolutionary effects of GE insect releases. We apply this framework to the Anopheles gambiae mosquito – a malaria vector being engineered to suppress the wild mosquito population – to identify effects that may occur during the transitory and steady state phases after release. Our methodology reveals many potential effects in each phase, perhaps most notably those dealing with immunity in the transitory phase, and with pathogen and vector evolution in the steady state phase. Importantly, this framework identifies knowledge gaps in mosquito ecology. Identifying effects in the transitory and steady state phases allows more rigorous identification of the potential ecological effects of GE insect release. PMID:24198955

Effects of government spending on research workforce development: evidence from biomedical postdoctoral researchers.

PubMed

Hur, Hyungjo; Ghaffarzadegan, Navid; Hawley, Joshua

2015-01-01

We examine effects of government spending on postdoctoral researchers' (postdocs) productivity in biomedical sciences, the largest population of postdocs in the US. We analyze changes in the productivity of postdocs before and after the US government's 1997 decision to increase NIH funding. In the first round of analysis, we find that more government spending has resulted in longer postdoc careers. We see no significant changes in researchers' productivity in terms of publication and conference presentations. However, when the population is segmented by citizenship, we find that the effects are heterogeneous; US citizens stay longer in postdoc positions with no change in publications and, in contrast, international permanent residents (green card holders) produce more conference papers and publications without significant changes in postdoc duration. Possible explanations and policy implications of the analysis are discussed.

Effects of Government Spending on Research Workforce Development: Evidence from Biomedical Postdoctoral Researchers

PubMed Central

Hur, Hyungjo; Ghaffarzadegan, Navid; Hawley, Joshua

2015-01-01

We examine effects of government spending on postdoctoral researchers’ (postdocs) productivity in biomedical sciences, the largest population of postdocs in the US. We analyze changes in the productivity of postdocs before and after the US government’s 1997 decision to increase NIH funding. In the first round of analysis, we find that more government spending has resulted in longer postdoc careers. We see no significant changes in researchers’ productivity in terms of publication and conference presentations. However, when the population is segmented by citizenship, we find that the effects are heterogeneous; US citizens stay longer in postdoc positions with no change in publications and, in contrast, international permanent residents (green card holders) produce more conference papers and publications without significant changes in postdoc duration. Possible explanations and policy implications of the analysis are discussed. PMID:25932942

Using the satellite-derived NDVI to assess ecological responses to environmental change.

PubMed

Pettorelli, Nathalie; Vik, Jon Olav; Mysterud, Atle; Gaillard, Jean-Michel; Tucker, Compton J; Stenseth, Nils Chr

2005-09-01

Assessing how environmental changes affect the distribution and dynamics of vegetation and animal populations is becoming increasingly important for terrestrial ecologists to enable better predictions of the effects of global warming, biodiversity reduction or habitat degradation. The ability to predict ecological responses has often been hampered by our rather limited understanding of trophic interactions. Indeed, it has proven difficult to discern direct and indirect effects of environmental change on animal populations owing to limited information about vegetation at large temporal and spatial scales. The rapidly increasing use of the Normalized Difference Vegetation Index (NDVI) in ecological studies has recently changed this situation. Here, we review the use of the NDVI in recent ecological studies and outline its possible key role in future research of environmental change in an ecosystem context.

Water, climate change and society in Bangladesh

NASA Astrophysics Data System (ADS)

Thiele-Eich, I.; Simmer, C.

2017-12-01

Dhaka, the capital of Bangladesh with a population of over 17 million people, is among the top five coastal cities most vulnerable to climate change, with over 30 % of the population living in slums. Effective disaster mitigation and adaptation requires an understanding how hazards such as flooding impact the population. The impacts of climate change on flooding and thus livelihoods in the complex delta of the Ganges-Brahmaputra-Meghna rivers can not be treated isolated from other anthropogenic impacts due to e.g. the construction of dams as well as a growing population. We illustrate this by setting up a conceptual socio-hydrological causal network using the enhanced Driving force - Pressure - State - Impact - Response framework. The constructed socio-hydrological framework includes both natural and anthropogenic processes and their two-way feedbacks, allowing policy makers to know where available resources can be used effectively to increase resilience and reduce vulnerability. We conclude that climate change takes place over long stretches of time and thus enable the population of Bangladesh to adapt slowly. Resources such as social capital, which is one of the main tools for slum dwellers to be able to cope with flooding can be altered over time, and as such the system can be considered overall stable and resilient. However, transboundary water sharing issues during the dry season and other implications resulting from dam structures such as Farakka Barrage complicate a prognosis on how the rapidly growing population will be affected in the 21st century. This is particularly important in connection with previous findings, which suggest that the Greater Dhaka population already experience a significant increase in mortality during droughts. Climate change can thus be seen as an anthropogenic amplification of the socio-hydrological challenges already faced by Bangladesh today.

Improving Aquatic Warbler Population Assessments by Accounting for Imperfect Detection

PubMed Central

Oppel, Steffen; Marczakiewicz, Piotr; Lachmann, Lars; Grzywaczewski, Grzegorz

2014-01-01

Monitoring programs designed to assess changes in population size over time need to account for imperfect detection and provide estimates of precision around annual abundance estimates. Especially for species dependent on conservation management, robust monitoring is essential to evaluate the effectiveness of management. Many bird species of temperate grasslands depend on specific conservation management to maintain suitable breeding habitat. One such species is the Aquatic Warbler (Acrocephalus paludicola), which breeds in open fen mires in Central Europe. Aquatic Warbler populations have so far been assessed using a complete survey that aims to enumerate all singing males over a large area. Because this approach provides no estimate of precision and does not account for observation error, detecting moderate population changes is challenging. From 2011 to 2013 we trialled a new line transect sampling monitoring design in the Biebrza valley, Poland, to estimate abundance of singing male Aquatic Warblers. We surveyed Aquatic Warblers repeatedly along 50 randomly placed 1-km transects, and used binomial mixture models to estimate abundances per transect. The repeated line transect sampling required 150 observer days, and thus less effort than the traditional ‘full count’ approach (175 observer days). Aquatic Warbler abundance was highest at intermediate water levels, and detection probability varied between years and was influenced by vegetation height. A power analysis indicated that our line transect sampling design had a power of 68% to detect a 20% population change over 10 years, whereas raw count data had a 9% power to detect the same trend. Thus, by accounting for imperfect detection we increased the power to detect population changes. We recommend to adopt the repeated line transect sampling approach for monitoring Aquatic Warblers in Poland and in other important breeding areas to monitor changes in population size and the effects of habitat management. PMID:24713994

Quaternary climate change and social behavior shaped the genetic differentiation of an endangered montane primate from the southern edge of the Tibetan Plateau.

PubMed

Chakraborty, Debapriyo; Ramakrishnan, Uma; Sinha, Anindya

2015-03-01

Multiple factors, including climate change, dispersal barriers, and social behavior influence the genetic structure of natural populations. While the effects of extrinsic factors such as historical climatic change and habitat topography have been well studied, mostly in temperate habitats, the simultaneous effects of intrinsic factors such as social behavior on genetic structure have rarely been explored. Such simultaneous effect, however, may particularly be common in social mammals such as many primates. Consequently, we studied the population structure of a rare and endangered social primate, the Arunachal macaque Macaca munzala, endemic to the northeastern Indian state of Arunachal Pradesh, located on the subtropical southern edge of the Tibetan Plateau and forming part of the Eastern Himalayan biodiversity hotspot. We studied a 534 bp-long mitochondrial DNA sequence and 22 autosomal microsatellite loci in individuals from three populations, Tawang, Upper Subansiri, and West Siang. The mtDNA data revealed three major divergence events: that between the Arunachal and bonnet macaques (ca. 1.61 mya), the founding of the West Siang population and the ancestral population of the present-day bonnet macaques (ca. 1.32 mya), and the divergence between the Tawang and Upper Subansiri populations (ca. 0.80 mya) that coincided with the major glacial events in the region. Comparing mitochondrial DNA with autosomal microsatellites, we also found evidence for female philopatry and male-driven long-distance gene flow. Arunachal macaques thus appear to be characterized by groups of philopatric females separated by geographical barriers and harsh climate but with dispersing males exerting a homogenizing effect on the nuclear gene pool. Given that severe population differentiation is of major concern in species conservation, we suggest that our study populations represent significant conservation units of this rare, endangered primate but, more importantly, emphasize the complex interplay of extrinsic and intrinsic factors in shaping the population structure of a social mammalian species. © 2014 Wiley Periodicals, Inc.

Linking population, fertility, and family planning with adaptation to climate change: perspectives from Ethiopia.

PubMed

Rovin, Kimberly; Hardee, Karen; Kidanu, Aklilu

2013-09-01

Global climate change is felt disproportionately in the world's most economically disadvantaged countries. As adaption to an evolving climate becomes increasingly salient on national and global scales, it is important to assess how people at the local-level are already coping with changes. Understanding local responses to climate change is essential for helping countries to construct strategies to bolster resilience to current and future effects. This qualitative research investigated responses to climate change in Ethiopia; specifically, how communities react to and cope with climate variation, which groups are most vulnerable, and the role of family planning in increasing resilience. Participants were highly aware of changing climate effects, impacts of rapid population growth, and the need for increased access to voluntary family planning. Identification of family planning as an important adaptation strategy supports the inclusion of rights-based voluntary family planning and reproductive health into local and national climate change adaptation plans.

Population Density Modulates Drug Inhibition and Gives Rise to Potential Bistability of Treatment Outcomes for Bacterial Infections.

PubMed

Karslake, Jason; Maltas, Jeff; Brumm, Peter; Wood, Kevin B

2016-10-01

The inoculum effect (IE) is an increase in the minimum inhibitory concentration (MIC) of an antibiotic as a function of the initial size of a microbial population. The IE has been observed in a wide range of bacteria, implying that antibiotic efficacy may depend on population density. Such density dependence could have dramatic effects on bacterial population dynamics and potential treatment strategies, but explicit measures of per capita growth as a function of density are generally not available. Instead, the IE measures MIC as a function of initial population size, and population density changes by many orders of magnitude on the timescale of the experiment. Therefore, the functional relationship between population density and antibiotic inhibition is generally not known, leaving many questions about the impact of the IE on different treatment strategies unanswered. To address these questions, here we directly measured real-time per capita growth of Enterococcus faecalis populations exposed to antibiotic at fixed population densities using multiplexed computer-automated culture devices. We show that density-dependent growth inhibition is pervasive for commonly used antibiotics, with some drugs showing increased inhibition and others decreased inhibition at high densities. For several drugs, the density dependence is mediated by changes in extracellular pH, a community-level phenomenon not previously linked with the IE. Using a simple mathematical model, we demonstrate how this density dependence can modulate population dynamics in constant drug environments. Then, we illustrate how time-dependent dosing strategies can mitigate the negative effects of density-dependence. Finally, we show that these density effects lead to bistable treatment outcomes for a wide range of antibiotic concentrations in a pharmacological model of antibiotic treatment. As a result, infections exceeding a critical density often survive otherwise effective treatments.

Population Density Modulates Drug Inhibition and Gives Rise to Potential Bistability of Treatment Outcomes for Bacterial Infections

PubMed Central

Maltas, Jeff; Brumm, Peter; Wood, Kevin B.

2016-01-01

The inoculum effect (IE) is an increase in the minimum inhibitory concentration (MIC) of an antibiotic as a function of the initial size of a microbial population. The IE has been observed in a wide range of bacteria, implying that antibiotic efficacy may depend on population density. Such density dependence could have dramatic effects on bacterial population dynamics and potential treatment strategies, but explicit measures of per capita growth as a function of density are generally not available. Instead, the IE measures MIC as a function of initial population size, and population density changes by many orders of magnitude on the timescale of the experiment. Therefore, the functional relationship between population density and antibiotic inhibition is generally not known, leaving many questions about the impact of the IE on different treatment strategies unanswered. To address these questions, here we directly measured real-time per capita growth of Enterococcus faecalis populations exposed to antibiotic at fixed population densities using multiplexed computer-automated culture devices. We show that density-dependent growth inhibition is pervasive for commonly used antibiotics, with some drugs showing increased inhibition and others decreased inhibition at high densities. For several drugs, the density dependence is mediated by changes in extracellular pH, a community-level phenomenon not previously linked with the IE. Using a simple mathematical model, we demonstrate how this density dependence can modulate population dynamics in constant drug environments. Then, we illustrate how time-dependent dosing strategies can mitigate the negative effects of density-dependence. Finally, we show that these density effects lead to bistable treatment outcomes for a wide range of antibiotic concentrations in a pharmacological model of antibiotic treatment. As a result, infections exceeding a critical density often survive otherwise effective treatments. PMID:27764095

Interannual bumble bee abundance is driven by indirect climate effects on floral resource phenology.

PubMed

Ogilvie, Jane E; Griffin, Sean R; Gezon, Zachariah J; Inouye, Brian D; Underwood, Nora; Inouye, David W; Irwin, Rebecca E

2017-12-01

Climate change can influence consumer populations both directly, by affecting survival and reproduction, and indirectly, by altering resources. However, little is known about the relative importance of direct and indirect effects, particularly for species important to ecosystem functioning, like pollinators. We used structural equation modelling to test the importance of direct and indirect (via floral resources) climate effects on the interannual abundance of three subalpine bumble bee species. In addition, we used long-term data to examine how climate and floral resources have changed over time. Over 8 years, bee abundances were driven primarily by the indirect effects of climate on the temporal distribution of floral resources. Over 43 years, aspects of floral phenology changed in ways that indicate species-specific effects on bees. Our study suggests that climate-driven alterations in floral resource phenology can play a critical role in governing bee population responses to global change. © 2017 John Wiley & Sons Ltd/CNRS.

[Regional differences in the development of hospitalizations : An effect of different demographic trends?

PubMed

Nowossadeck, Enno; Prütz, Franziska

2018-03-01

Population aging and population decline in many regions of the Federal Republic of Germany are key elements of demographic change. In the regions concerned there is a rising number of older people and, simultaneously, a declining population. So far, the consequences of regional shrinkage and growth for inpatient care don't seem to have been analysed very well. This paper analyses the influence of population aging and declining/increasing population (demographic factors) as well as other, non-demographic factors on the number of hospitalizations in Germany and the Federal States since 2000.One result of the analysis is that there are major differences between the Federal States. The analysis shows, for example, an increase of hospitalizations in Berlin while in Saxony-Anhalt the number of hospitalizations declines. The increase in Berlin was the result of population aging and, to a lower extent, an increase in population. In Saxony-Anhalt the declining population resulted in a decreasing number of hospitalizations. Population aging and non-demographic factors were not able to compensate this trend.Overall, the effect of demographic factors on the number of hospitalizations remains constant over time. Short-term changes of hospitalizations are due to non-demographic factors, such as epidemiological trends, (for example trends of incidence or prevalence), or structural changes of health care service (for example patients shifting between different sectors of health care or the introduction of new reimbursement systems).

Calcification, Storm Damage and Population Resilience of Tabular Corals under Climate Change

PubMed Central

Madin, Joshua S.; Hughes, Terry P.; Connolly, Sean R.

2012-01-01

Two facets of climate change–increased tropical storm intensity and ocean acidification–are expected to detrimentally affect reef-building organisms by increasing their mortality rates and decreasing their calcification rates. Our current understanding of these effects is largely based on individual organisms’ short-term responses to experimental manipulations. However, predicting the ecologically-relevant effects of climate change requires understanding the long-term demographic implications of these organism-level responses. In this study, we investigate how storm intensity and calcification rate interact to affect population dynamics of the table coral Acropora hyacinthus, a dominant and geographically widespread ecosystem engineer on wave-exposed Indo-Pacific reefs. We develop a mechanistic framework based on the responses of individual-level demographic rates to changes in the physical and chemical environment, using a size-structured population model that enables us to rigorously incorporate uncertainty. We find that table coral populations are vulnerable to future collapse, placing in jeopardy many other reef organisms that are dependent upon them for shelter and food. Resistance to collapse is largely insensitive to predicted changes in storm intensity, but is highly dependent on the extent to which calcification influences both the mechanical properties of reef substrate and the colony-level trade-off between growth rate and skeletal strength. This study provides the first rigorous quantitative accounting of the demographic implications of the effects of ocean acidification and changes in storm intensity, and provides a template for further studies of climate-induced shifts in ecosystems, including coral reefs. PMID:23056379

Modeling tradeoffs in avian life history traits and consequences for population growth

USGS Publications Warehouse

Clark, M.E.; Martin, T.E.

2007-01-01

Variation in population dynamics is inherently related to life history characteristics of species, which vary markedly even within phylogenetic groups such as passerine birds. We computed the finite rate of population change (??) from a matrix projection model and from mark-recapture observations for 23 bird species breeding in northern Arizona. We used sensitivity analyses and a simulation model to separate contributions of different life history traits to population growth rate. In particular we focused on contrasting effects of components of reproduction (nest success, clutch size, number of clutches, and juvenile survival) versus adult survival on ??. We explored how changes in nest success or adult survival coupled to costs in other life history parameters affected ?? over a life history gradient provided by our 23 Arizona species, as well as a broader sample of 121 North American passerine species. We further examined these effects for more than 200 passeriform and piciform populations breeding across North America. Model simulations indicate nest success and juvenile survival exert the largest effects on population growth in species with moderate to high reproductive output, whereas adult survival contributed more to population growth in long-lived species. Our simulations suggest that monitoring breeding success in populations across a broad geographic area provides an important index for identifying neotropical migratory populations at risk of serious population declines and a potential method for identifying large-scale mechanisms regulating population dynamics. ?? 2007 Elsevier B.V. All rights reserved.

Trapped in Place? Segmented Resilience to Hurricanes in the Gulf Coast, 1970-2005.

PubMed

Logan, John R; Issar, Sukriti; Xu, Zengwang

2016-10-01

Hurricanes pose a continuing hazard to populations in coastal regions. This study estimates the impact of hurricanes on population change in the years 1970-2005 in the U.S. Gulf Coast region. Geophysical models are used to construct a unique data set that simulates the spatial extent and intensity of wind damage and storm surge from the 32 hurricanes that struck the region in this period. Multivariate spatial time-series models are used to estimate the impacts of hurricanes on population change. Population growth is found to be reduced significantly for up to three successive years after counties experience wind damage, particularly at higher levels of damage. Storm surge is associated with reduced population growth in the year after the hurricane. Model extensions show that change in the white and young adult population is more immediately and strongly affected than is change for blacks and elderly residents. Negative effects on population are stronger in counties with lower poverty rates. The differentiated impact of hurricanes on different population groups is interpreted as segmented withdrawal-a form of segmented resilience in which advantaged population groups are more likely to move out of or avoid moving into harm's way while socially vulnerable groups have fewer choices.

Trapped in Place? Segmented Resilience to Hurricanes in the Gulf Coast, 1970–2005

PubMed Central

Logan, John R.; Issar, Sukriti; Xu, Zengwang

2016-01-01

Hurricanes pose a continuing hazard to populations in coastal regions. This study estimates the impact of hurricanes on population change in the years 1970–2005 in the U.S. Gulf Coast region. Geophysical models are used to construct a unique data set that simulates the spatial extent and intensity of wind damage and storm surge from the 32 hurricanes that struck the region in this period. Multivariate spatial time-series models are used to estimate the impacts of hurricanes on population change. Population growth is found to be reduced significantly for up to three successive years after counties experience wind damage, particularly at higher levels of damage. Storm surge is associated with reduced population growth in the year after the hurricane. Model extensions show that change in the white and young adult population is more immediately and strongly affected than is change for blacks and elderly residents. Negative effects on population are stronger in counties with lower poverty rates. The differentiated impact of hurricanes on different population groups is interpreted as segmented withdrawal—a form of segmented resilience in which advantaged population groups are more likely to move out of or avoid moving into harm’s way while socially vulnerable groups have fewer choices. PMID:27531504

Multidisciplinary population monitoring when demographic data are sparse: a case study of remote trout populations

PubMed Central

Fraser, Dylan J; Calvert, Anna M; Bernatchez, Louis; Coon, Andrew

2013-01-01

The potential of genetic, genomic, and phenotypic metrics for monitoring population trends may be especially high in isolated regions, where traditional demographic monitoring is logistically difficult and only sporadic sampling is possible. This potential, however, is relatively underexplored empirically. Over eleven years, we assessed several such metrics along with traditional ecological knowledge and catch data in a socioeconomically important trout species occupying a large, remote lake. The data revealed largely stable characteristics in two populations over 2–3 generations, but possible contemporary changes in a third population. These potential shifts were suggested by reduced catch rates, reduced body size, and changes in selection implied at one gene-associated single nucleotide polymorphism. A demographic decline in this population, however, was ambiguously supported, based on the apparent lack of temporal change in effective population size, and corresponding traditional knowledge suggesting little change in catch. We illustrate how the pluralistic approach employed has practicality for setting future monitoring efforts of these populations, by guiding monitoring priorities according to the relative merits of different metrics and availability of resources. Our study also considers some advantages and disadvantages to adopting a pluralistic approach to population monitoring where demographic data are not easily obtained. PMID:24455128

Climate and demography in early prehistory: using calibrated (14)C dates as population proxies.

PubMed

Riede, Felix

2009-04-01

Although difficult to estimate for prehistoric hunter-gatherer populations, demographic variables-population size, density, and the connectedness of demes-are critical for a better understanding of the processes of material culture change, especially in deep prehistory. Demography is the middle-range link between climatic changes and both biological and cultural evolutionary trajectories of human populations. Much of human material culture functions as a buffer against climatic changes, and the study of prehistoric population dynamics, estimated through changing frequencies of calibrated radiocarbon dates, therefore affords insights into how effectively such buffers operated and when they failed. In reviewing a number of case studies (Mesolithic Ireland, the origin of the Bromme culture, and the earliest late glacial human recolonization of southern Scandinavia), I suggest that a greater awareness of demographic processes, and in particular of demographic declines, provides many fresh insights into what structured the archaeological record. I argue that we cannot sideline climatic and environmental factors or extreme geophysical events in our reconstructions of prehistoric culture change. The implications of accepting demographic variability as a departure point for evaluating the archaeological record are discussed.

Contaminant effects on Great Lakes' fish-eating birds: a population perspective

USGS Publications Warehouse

Heinz, G.H.; Kendall, Ronald J.; Dickerson, Richard L.; Giesy, John P.; Suk, William P.

1998-01-01

Preventing environmental contaminants from reducing wildlife populations is the greatest concern in wildlife toxicology. In the Great Lakes, environmental contaminants have a history of reducing populations of many species of fish-eating birds. Endocrine effects may have contributed to declines in fish-eating bird populations, but the overriding harm was caused by DDE-induced eggshell thinning. Toxic effects may still be occurring today, but apparently they are not of a sufficient magnitude to depress populations of most fish-eating birds. Once DDE levels in the Great Lakes declined, eggshells of birds began to get thicker and reproductive success improved. Populations of double-crested cormorants (Phalacrocorax auritus) and ring-billed gulls (Larus delawarensis) have increased dramatically since the bans on DDT and other organochlorine pesticides. Bald eagles (Haliaeetus leucocephalus) are still not reproducing at a normal rate along the shores of the Great Lakes, but success is much improved compared to earlier records when eggshell thinning was worse. Other species, such as herring gulls (Larus argentatus) and black-crowned night-herons (Nycticorax nycticorax), seem to be having improved reproductive success, but data on Great Lakes'-wide population changes are incomplete. Reproductive success of common terns (Sterna hirundo), Caspian terns (Sterna caspia), and Forster's terns (Sterna forsteri) seems to have improved in recent years, but, again, data on population changes are not very complete, and these birds face many habitat related problems as well as contaminant problems. Although contaminants are still producing toxic effects, and these effects may include endocrine disfunction, fish-eating birds in the Great Lakes seem to be largely weathering these effects, at least as far as populations are concerned. A lack of obvious contaminant effects on populations of fish-eating birds in the Great Lakes, however, should not be equated with a lack of any harm to these birds or with a conclusion that certain contaminants do not need additional control.

The Population Activist's Handbook.

ERIC Educational Resources Information Center

Population Inst., Washington, DC.

This handbook is a guide to effective action strategies on dealing with overpopulation. Divided into five sections, the book outlines programs, suggests references, and lists resources that are helpful for thinking and for planning action on population issues. Section one focuses on strategies to change the current population policy choices made…

Analysis of population genetic structure and gene flow in an annual plant before and after a rapid evolutionary response to drought.

PubMed

Welt, Rachel S; Litt, Amy; Franks, Steven J

2015-03-27

The impact of environmental change on population structure is not well understood. This study aimed to examine the effect of a climate change event on gene flow over space and time in two populations of Brassica rapa that evolved more synchronous flowering times over 5 years of drought in southern California. Using plants grown from seeds collected before and after the drought, we estimated genetic parameters within and between populations and across generations. We expected that with greater temporal opportunity to cross-pollinate, due to reduced phenological isolation, these populations would exhibit an increase in gene flow following the drought. We found low but significant FST, but no change in FST or Nm across the drought, in contrast to predictions. Bayesian analysis of these data indicates minor differentiation between the two populations but no noticeable change in structure before and after the shift in flowering times. However, we found high and significant levels of FIS, indicating that inbreeding likely occurred in these populations despite self-incompatibility in B. rapa. In this system, we did not find an impact of climate change on gene flow or population structuring. The contribution of gene flow to adaptive evolution may vary by system, however, and is thus an important parameter to consider in further studies of natural responses to environmental change. Published by Oxford University Press on behalf of the Annals of Botany Company.

Shaping Policy Change in Population Health: Policy Entrepreneurs, Ideas, and Institutions.

PubMed

Béland, Daniel; Katapally, Tarun R

2018-01-14

Political realities and institutional structures are often ignored when gathering evidence to influence population health policies. If these policies are to be successful, social science literature on policy change should be integrated into the population health approach. In this contribution, drawing on the work of John W. Kingdon and related scholarship, we set out to examine how key components of the policy change literature could contribute towards the effective development of population health policies. Shaping policy change would require a realignment of the existing school of thought, where the contribution of population health seems to end at knowledge translation. Through our critical analysis of selected literature, we extend recommendations to advance a burgeoning discussion in adopting new approaches to successfully implement evidence-informed population health policies. © 2018 The Author(s); Published by Kerman University of Medical Sciences. This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Genetic effects of chronic habitat fragmentation in a wind-pollinated tree

PubMed Central

Jump, Alistair S.; Peñuelas, Josep

2006-01-01

Habitat fragmentation poses a serious threat to plants through genetic changes associated with increased isolation and reduced population size. However, the longevity of trees, combined with effective seed or pollen dispersal, can enhance their resistance to these effects. The European beech (Fagus sylvatica) dominates forest over large regions of Europe. We demonstrate that habitat fragmentation in this species has led to genetic bottlenecks and the disruption of the species' breeding system, leading to significantly elevated levels of inbreeding, population divergence, and reduced genetic diversity within populations. These results show that, in contrast with the findings of previous studies, forest fragmentation has a negative genetic impact, even in this widespread, wind-pollinated tree. The identification of significant effects of forest fragmentation in beech demonstrates that trees are not at reduced risk from environmental change. This should be accounted for in the management of remaining natural and seminatural forest throughout the world. PMID:16698935

Climate and sex ratio variation in a viviparous lizard.

PubMed

Cunningham, George D; While, Geoffrey M; Wapstra, Erik

2017-05-01

The extent to which key biological processes, such as sex determination, respond to environmental fluctuations is fundamental for assessing species' susceptibility to ongoing climate change. Few studies, however, address how climate affects offspring sex in the wild. We monitored two climatically distinct populations of the viviparous skink Niveoscincus ocellatus for 16 years, recording environmental temperatures, offspring sex and date of birth. We found strong population-specific effects of temperature on offspring sex, with female offspring more common in warm years at the lowland site but no effect at the highland site. In contrast, date of birth advanced similarly in response to temperature at both sites. These results suggest strong population-specific effects of temperature on offspring sex that are independent of climatic effects on other physiological processes. These results have significant implications for our understanding of the ecological and evolutionary consequences of variation in sex ratios under climate change. © 2017 The Author(s).

Quantifying the health impacts of air pollution under a changing climate-a review of approaches and methodology.

PubMed

Sujaritpong, Sarunya; Dear, Keith; Cope, Martin; Walsh, Sean; Kjellstrom, Tord

2014-03-01

Climate change has been predicted to affect future air quality, with inevitable consequences for health. Quantifying the health effects of air pollution under a changing climate is crucial to provide evidence for actions to safeguard future populations. In this paper, we review published methods for quantifying health impacts to identify optimal approaches and ways in which existing challenges facing this line of research can be addressed. Most studies have employed a simplified methodology, while only a few have reported sensitivity analyses to assess sources of uncertainty. The limited investigations that do exist suggest that examining the health risk estimates should particularly take into account the uncertainty associated with future air pollution emissions scenarios, concentration-response functions, and future population growth and age structures. Knowledge gaps identified for future research include future health impacts from extreme air pollution events, interactions between temperature and air pollution effects on public health under a changing climate, and how population adaptation and behavioural changes in a warmer climate may modify exposure to air pollution and health consequences.

Mate choice theory and the mode of selection in sexual populations.

PubMed

Carson, Hampton L

2003-05-27

Indirect new data imply that mate and/or gamete choice are major selective forces driving genetic change in sexual populations. The system dictates nonrandom mating, an evolutionary process requiring both revised genetic theory and new data on heritability of characters underlying Darwinian fitness. Successfully reproducing individuals represent rare selections from among vigorous, competing survivors of preadult natural selection. Nonrandom mating has correlated demographic effects: reduced effective population size, inbreeding, low gene flow, and emphasis on deme structure. Characters involved in choice behavior at reproduction appear based on quantitative trait loci. This variability serves selection for fitness within the population, having only an incidental relationship to the origin of genetically based reproductive isolation between populations. The claim that extensive hybridization experiments with Drosophila indicate that selection favors a gradual progression of "isolating mechanisms" is flawed, because intra-group random mating is assumed. Over deep time, local sexual populations are strong, independent genetic systems that use rich fields of variable polygenic components of fitness. The sexual reproduction system thus particularizes, in small subspecific populations, the genetic basis of the grand adaptive sweep of selective evolutionary change, much as Darwin proposed.

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

USGS Publications Warehouse

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

2014-01-01

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

An ecological model of the habitat mosaic in estuarine nursery areas: Part II – Projecting effects of sea level rise on fish production

EPA Science Inventory

Understanding the response of fish populations to habitat change mediated by sea level rise (SLR) is a key component of ecosystem-based management. Yet, no direct link has been established between habitat change due to SLR and fish population production. Here we take a coupled ...

Temporally increasing spatial synchrony of North American temperature and bird populations

NASA Astrophysics Data System (ADS)

Koenig, Walter D.; Liebhold, Andrew M.

2016-06-01

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

Effective population size dynamics reveal impacts of historic climatic events and recent anthropogenic pressure in African elephants.

PubMed

Okello, J B A; Wittemyer, G; Rasmussen, H B; Arctander, P; Nyakaana, S; Douglas-Hamilton, I; Siegismund, H R

2008-09-01

Two hundred years of elephant hunting for ivory, peaking in 1970-1980s, caused local extirpations and massive population declines across Africa. The resulting genetic impacts on surviving populations have not been studied, despite the importance of understanding the evolutionary repercussions of such human-mediated events on this keystone species. Using Bayesian coalescent-based genetic methods to evaluate time-specific changes in effective population size, we analysed genetic variation in 20 highly polymorphic microsatellite loci from 400 elephants inhabiting the greater Samburu-Laikipia region of northern Kenya. This area experienced a decline of between 80% and 90% in the last few decades when ivory harvesting was rampant. The most significant change in effective population size, however, occurred approximately 2500 years ago during a mid-Holocene period of climatic drying in tropical Africa. Contrary to expectations, detailed analyses of four contemporary age-based cohorts showed that the peak poaching epidemic in the 1970s caused detectable temporary genetic impacts, with genetic diversity rebounding as juveniles surviving the poaching era became reproductively mature. This study demonstrates the importance of climatic history in shaping the distribution and genetic history of a keystone species and highlights the utility of coalescent-based demographic approaches in unravelling ancestral demographic events despite a lack of ancient samples. Unique insights into the genetic signature of mid-Holocene climatic change in Africa and effects of recent poaching pressure on elephants are discussed.

Disentangling density-dependent dynamics using full annual cycle models and Bayesian model weight updating

USGS Publications Warehouse

Robinson, Orin J.; McGowan, Conor P.; Devers, Patrick K.

2017-01-01

Density dependence regulates populations of many species across all taxonomic groups. Understanding density dependence is vital for predicting the effects of climate, habitat loss and/or management actions on wild populations. Migratory species likely experience seasonal changes in the relative influence of density dependence on population processes such as survival and recruitment throughout the annual cycle. These effects must be accounted for when characterizing migratory populations via population models.To evaluate effects of density on seasonal survival and recruitment of a migratory species, we used an existing full annual cycle model framework for American black ducks Anas rubripes, and tested different density effects (including no effects) on survival and recruitment. We then used a Bayesian model weight updating routine to determine which population model best fit observed breeding population survey data between 1990 and 2014.The models that best fit the survey data suggested that survival and recruitment were affected by density dependence and that density effects were stronger on adult survival during the breeding season than during the non-breeding season.Analysis also suggests that regulation of survival and recruitment by density varied over time. Our results showed that different characterizations of density regulations changed every 8–12 years (three times in the 25-year period) for our population.Synthesis and applications. Using a full annual cycle, modelling framework and model weighting routine will be helpful in evaluating density dependence for migratory species in both the short and long term. We used this method to disentangle the seasonal effects of density on the continental American black duck population which will allow managers to better evaluate the effects of habitat loss and potential habitat management actions throughout the annual cycle. The method here may allow researchers to hone in on the proper form and/or strength of density dependence for use in models for conservation recommendations.

Contrasting physiological responses to future ocean acidification among Arctic copepod populations.

PubMed

Thor, Peter; Bailey, Allison; Dupont, Sam; Calosi, Piero; Søreide, Janne E; De Wit, Pierre; Guscelli, Ella; Loubet-Sartrou, Lea; Deichmann, Ida M; Candee, Martin M; Svensen, Camilla; King, Andrew L; Bellerby, Richard G J

2018-01-01

Widespread ocean acidification (OA) is modifying the chemistry of the global ocean, and the Arctic is recognized as the region where the changes will progress at the fastest rate. Moreover, Arctic species show lower capacity for cellular homeostasis and acid-base regulation rendering them particularly vulnerable to OA. In the present study, we found physiological differences in OA response across geographically separated populations of the keystone Arctic copepod Calanus glacialis. In copepodites stage CIV, measured reaction norms of ingestion rate and metabolic rate showed severe reductions in ingestion and increased metabolic expenses in two populations from Svalbard (Kongsfjord and Billefjord) whereas no effects were observed in a population from the Disko Bay, West Greenland. At pH T 7.87, which has been predicted for the Svalbard west coast by year 2100, these changes resulted in reductions in scope for growth of 19% in the Kongsfjord and a staggering 50% in the Billefjord. Interestingly, these effects were not observed in stage CV copepodites from any of the three locations. It seems that CVs may be more tolerant to OA perhaps due to a general physiological reorganization to meet low intracellular pH during hibernation. Needless to say, the observed changes in the CIV stage will have serious implications for the C. glacialis population health status and growth around Svalbard. However, OA tolerant populations such as the one in the Disko Bay could help to alleviate severe effects in C. glacialis as a species. © 2017 John Wiley & Sons Ltd.

Disentangling the effects of climate, density dependence, and harvest on an iconic large herbivore's population dynamics.

PubMed

Koons, David N; Colchero, Fernando; Hersey, Kent; Gimenez, Olivier

2015-06-01

Understanding the relative effects of climate, harvest, and density dependence on population dynamics is critical for guiding sound population management, especially for ungulates in arid and semiarid environments experiencing climate change. To address these issues for bison in southern Utah, USA, we applied a Bayesian state-space model to a 72-yr time series of abundance counts. While accounting for known harvest (as well as live removal) from the population, we found that the bison population in southern Utah exhibited a strong potential to grow from low density (β0 = 0.26; Bayesian credible interval based on 95% of the highest posterior density [BCI] = 0.19-0.33), and weak but statistically significant density dependence (β1 = -0.02, BCI = -0.04 to -0.004). Early spring temperatures also had strong positive effects on population growth (Pfat1 = 0.09, BCI = 0.04-0.14), much more so than precipitation and other temperature-related variables (model weight > three times more than that for other climate variables). Although we hypothesized that harvest is the primary driving force of bison population dynamics in southern Utah, our elasticity analysis indicated that changes in early spring temperature could have a greater relative effect on equilibrium abundance than either harvest or. the strength of density dependence. Our findings highlight the utility of incorporating elasticity analyses into state-space population models, and the need to include climatic processes in wildlife management policies and planning.

Contemporary and historic factors influence differently genetic differentiation and diversity in a tropical palm

PubMed Central

da Silva Carvalho, C; Ribeiro, M C; Côrtes, M C; Galetti, M; Collevatti, R G

2015-01-01

Population genetics theory predicts loss in genetic variability because of drift and inbreeding in isolated plant populations; however, it has been argued that long-distance pollination and seed dispersal may be able to maintain gene flow, even in highly fragmented landscapes. We tested how historical effective population size, historical migration and contemporary landscape structure, such as forest cover, patch isolation and matrix resistance, affect genetic variability and differentiation of seedlings in a tropical palm (Euterpe edulis) in a human-modified rainforest. We sampled 16 sites within five landscapes in the Brazilian Atlantic forest and assessed genetic variability and differentiation using eight microsatellite loci. Using a model selection approach, none of the covariates explained the variation observed in inbreeding coefficients among populations. The variation in genetic diversity among sites was best explained by historical effective population size. Allelic richness was best explained by historical effective population size and matrix resistance, whereas genetic differentiation was explained by matrix resistance. Coalescence analysis revealed high historical migration between sites within landscapes and constant historical population sizes, showing that the genetic differentiation is most likely due to recent changes caused by habitat loss and fragmentation. Overall, recent landscape changes have a greater influence on among-population genetic variation than historical gene flow process. As immediate restoration actions in landscapes with low forest amount, the development of more permeable matrices to allow the movement of pollinators and seed dispersers may be an effective strategy to maintain microevolutionary processes. PMID:25873150

Climate change, food, water and population health in China.

PubMed

Tong, Shilu; Berry, Helen L; Ebi, Kristie; Bambrick, Hilary; Hu, Wenbiao; Green, Donna; Hanna, Elizabeth; Wang, Zhiqiang; Butler, Colin D

2016-10-01

Anthropogenic climate change appears to be increasing the frequency, duration and intensity of extreme weather events. Such events have already had substantial impacts on socioeconomic development and population health. Climate change's most profound impacts are likely to be on food, health systems and water. This paper explores how climate change will affect food, human health and water in China. Projections indicate that the overall effects of climate change, land conversion and reduced water availability could reduce Chinese food production substantially - although uncertainty is inevitable in such projections. Climate change will probably have substantial impacts on water resources - e.g. changes in rainfall patterns and increases in the frequencies of droughts and floods in some areas of China. Such impacts would undoubtedly threaten population health and well-being in many communities. In the short-term, population health in China is likely to be adversely affected by increases in air temperatures and pollution. In the medium to long term, however, the indirect impacts of climate change - e.g. changes in the availability of food, shelter and water, decreased mental health and well-being and changes in the distribution and seasonality of infectious diseases - are likely to grow in importance. The potentially catastrophic consequences of climate change can only be avoided if all countries work together towards a substantial reduction in the emission of so-called greenhouse gases and a substantial increase in the global population's resilience to the risks of climate variability and change.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morrison, P.

Shifts in American population dynamics during the last two decades, a period of lower birthrates and changes in age and place distribution, reflect new attitudes toward childbearing and family orientation that will have a profound effect in the next century. Demographers project a range in population growth between 1.7 and 2.7%, with more attention being given to who has children, whether or when they have them, and the changing economic role of women. Changes in age distribution lead to shifts in demand for related public services, especially affecting the financing of schools and Social Security. Population migration from metropolitan areasmore » and from the Snow to the Sun Belt has caused urban and regional problems. Demographic changes affect redistribution programs and undermine the traditional economic and political framework for carrying out redistribution. They affect census accuracy, labor-pool quality, public dependency, problems of illegal aliens, and require local fiscal adjustments to either a shrinking or a growing population.« less

Theoretical electron scattering amplitudes and spin polarizations. Electron energies 100 to 1500 eV Part II. Be, N, O, Al, Cl, V, Co, Cu, As, Nb, Ag, Sn, Sb, I, and Ta targets

NASA Astrophysics Data System (ADS)

Wildhaber, M. L.; Wikle, C. K.; Anderson, C. J.; Franz, K. J.; Moran, E. H.; Dey, R.

2012-12-01

Recent decades have brought substantive changes in land use and climate across the earth, prompting a need to think of population and community ecology not as a static entity, but as a dynamic process. Increasingly there is evidence of ecological changes due to climate change. Although much of this evidence comes from ground-truth observations of biogeographic data, there is increasing reliance on models that relate climate variables to biological systems. Such models can then be used to explore potential changes to population and community level ecological systems in response to climate scenarios as obtained from global climate models (GCMs). A key issue associated with modeling ecosystem response to climate is GCM downscaling to regional and local ecological/biological response models that can be used in vulnerability and risk assessments of the potential effects of climate change. The need is for an explicit means for scaling results up or down multiple hierarchical levels and an effective assessment of the level of uncertainty surrounding current knowledge, data, and data collection methods with these goals identified as in need of acceleration in the U.S. Climate Change Science Program FY2009 Implementation Priorities. In the end, such work should provide the information needed to develop adaptation and mitigation methodologies to minimize the effects of directional and nonlinear climate change on the Nation's land, water, ecosystems, and biological populations. We are working to develop an approach that includes multi-scale and hierarchical Bayesian modeling of Missouri River sturgeon population dynamics. Statistical linkages are defined to quantify implications of climate on fish populations of the Missouri River ecosystem. This approach is a hybrid between physical (deterministic) downscaling and statistical downscaling, recognizing that there is uncertainty in both. The model must include linkages between climate and habitat, and between habitat and population. A key advantage of the hierarchical approach used in this study is that it incorporates various sources of observations and includes established scientific knowledge, and associated uncertainties. The goal is to evaluate the potential distributional changes in an ecological system, given distributional changes implied by a series of linked climate and system models under various emissions/use scenarios. The predictive modeling system being developed will be a powerful tool for evaluating management options for coping with global change consequences and assessing uncertainty of those evaluations. Specifically for the endangered pallid sturgeon (Scaphirhynchus albus), we are already able to assess potential effects of any climate scenario on growth and population size distribution. Future models will incorporate survival and reproduction. Ultimately, these models provide guidance for successful recovery and conservation of the pallid sturgeon. Here we present a basic outline of the approach we are developing and a simple pallid sturgeon example to demonstrate how multiple scales and parameter uncertainty are incorporated.

Projection of temperature-related mortality due to cardiovascular disease in beijing under different climate change, population, and adaptation scenarios.

PubMed

Zhang, Boya; Li, Guoxing; Ma, Yue; Pan, Xiaochuan

2018-04-01

Human health faces unprecedented challenges caused by climate change. Thus, studies of the effect of temperature change on total mortality have been conducted in numerous countries. However, few of those studies focused on temperature-related mortality due to cardiovascular disease (CVD) or considered future population changes and adaptation to climate change. We present herein a projection of temperature-related mortality due to CVD under different climate change, population, and adaptation scenarios in Beijing, a megacity in China. To this end, 19 global circulation models (GCMs), 3 representative concentration pathways (RCPs), 3 socioeconomic pathways, together with generalized linear models and distributed lag non-linear models, were used to project future temperature-related CVD mortality during periods centered around the years 2050 and 2070. The number of temperature-related CVD deaths in Beijing is projected to increase by 3.5-10.2% under different RCP scenarios compared with that during the baseline period. Using the same GCM, the future daily maximum temperatures projected using the RCP2.6, RCP4.5, and RCP8.5 scenarios showed a gradually increasing trend. When population change is considered, the annual rate of increase in temperature-related CVD deaths was up to fivefold greater than that under no-population-change scenarios. The decrease in the number of cold-related deaths did not compensate for the increase in that of heat-related deaths, leading to a general increase in the number of temperature-related deaths due to CVD in Beijing. In addition, adaptation to climate change may enhance rather than ameliorate the effect of climate change, as the increase in cold-related CVD mortality greater than the decrease in heat-related CVD mortality in the adaptation scenarios will result in an increase in the total number of temperature-related CVD mortalities. Copyright © 2018 Elsevier Inc. All rights reserved.

Effect of water and nitrogen additions on free-living nitrogen fixer populations in desert grass root zones.

PubMed Central

Herman, R P; Provencio, K R; Torrez, R J; Seager, G M

1993-01-01

In this study we measured changes in population levels of free-living N2-fixing bacteria in the root zones of potted Bouteloua eriopoda and Sporobolus flexuosus plants as well as the photosynthetic indices of the plants in response to added nitrogen, added water, and added water plus nitrogen treatments. In addition, N2 fixer population changes in response to added carbon source and nitrogen were measured in plant-free soil columns. There were significant increases in the numbers of N2 fixers associated with both plant species in the water and the water plus nitrogen treatments. Both treatments increased the photosynthetic index, suggesting that plant exudates were driving N2 fixer population changes. Population increases were greatest in the water plus nitrogen treatments, indicating that added nitrogen was synergistic with added water and suggesting that nitrogen addition spared bacteria the metabolic cost of N2 fixation, allowing greater reproduction. Plant-free column studies demonstrated a synergistic carbon-nitrogen effect when carbon levels were limiting (low malate addition) but not when carbon was abundant (high malate), further supporting this hypothesis. The results of this study indicate the presence of N2 fixer populations which interact with plants and which may play a role in the nitrogen balance of desert grasslands. PMID:8215373

Demographic Responses To Climate Manipulations Across a Species Range

NASA Astrophysics Data System (ADS)

Oldfather, M. F.

2016-12-01

Species biogeographic responses to climate change will occur through the local extinction and establishment of populations. The overall performance of populations across a species range is shaped by the idiosyncratic sensitivities of demographic rates to the changing climate conditions. Heterogeneous topography partially decouples temperature and soil moisture presenting an opportunity to disentangle demographic sensitivity to multiple local climate variables and refine range shift predictions in response to complex climate change. Since 2013, I have monitored 16 populations of a long-lived alpine plant, Ivesia lycopodioides var. scandularis (Rosaceae) across the entirety of its altitudinal range in the arid White Mountains, CA (3350 - 4420m). I quantified microclimatic soil moisture and temperature, and the demographic rates of over 4,000 individuals. Demographic rates exhibited sensitivity to accumulated degree-days (ex. reproduction), soil volumetric water content (ex. germination), or the interaction between these climate variables (ex. survival). These observations motivated an experimental test of the relationship between demography and local climate with manipulations of increased summertime temperature and precipitation in nine populations. All demographic rates were sensitive to the climate manipulations and the magnitude of the demographic response depended on the population's location within the range. However, the modeled population growth rate was only minimally affected by the manipulations in most populations. The inverse responses of many of the demographic rates may allow populations to demographically buffer against the climate manipulations. However, in one low elevation edge population the negative effect of heating on survival overwhelmed the positive effect on germination, indicating that the capacity of populations to demographically buffer may have a limit.

Lifestyle and Ice: The Relationship between Ecological Specialization and Response to Pleistocene Climate Change.

PubMed

Kašparová, Eva; Van de Putte, Anton P; Marshall, Craig; Janko, Karel

2015-01-01

Major climatic changes in the Pleistocene had significant effects on marine organisms and the environments in which they lived. The presence of divergent patterns of demographic history even among phylogenetically closely-related species sharing climatic changes raises questions as to the respective influence of species-specific traits on population structure. In this work we tested whether the lifestyle of Antarctic notothenioid benthic and pelagic fish species from the Southern Ocean influenced the concerted population response to Pleistocene climatic fluctuations. This was done by a comparative analysis of sequence variation at the cyt b and S7 loci in nine newly sequenced and four re-analysed species. We found that all species underwent more or less intensive changes in population size but we also found consistent differences between demographic histories of pelagic and benthic species. Contemporary pelagic populations are significantly more genetically diverse and bear traces of older demographic expansions than less diverse benthic species that show evidence of more recent population expansions. Our findings suggest that the lifestyles of different species have strong influences on their responses to the same environmental events. Our data, in conjunction with previous studies showing a constant diversification tempo of these species during the Pleistocene, support the hypothesis that Pleistocene glaciations had a smaller effect on pelagic species than on benthic species whose survival may have relied upon ephemeral refugia in shallow shelf waters. These findings suggest that the interaction between lifestyle and environmental changes should be considered in genetic analyses.

Behavioural responses to human-induced environmental change.

PubMed

Tuomainen, Ulla; Candolin, Ulrika

2011-08-01

The initial response of individuals to human-induced environmental change is often behavioural. This can improve the performance of individuals under sudden, large-scale perturbations and maintain viable populations. The response can also give additional time for genetic changes to arise and, hence, facilitate adaptation to new conditions. On the other hand, maladaptive responses, which reduce individual fitness, may occur when individuals encounter conditions that the population has not experienced during its evolutionary history, which can decrease population viability. A growing number of studies find human disturbances to induce behavioural responses, both directly and by altering factors that influence fitness. Common causes of behavioural responses are changes in the transmission of information, the concentration of endocrine disrupters, the availability of resources, the possibility of dispersal, and the abundance of interacting species. Frequent responses are alterations in habitat choice, movements, foraging, social behaviour and reproductive behaviour. Behavioural responses depend on the genetically determined reaction norm of the individuals, which evolves over generations. Populations first respond with individual behavioural plasticity, whereafter changes may arise through innovations and the social transmission of behavioural patterns within and across generations, and, finally, by evolution of the behavioural response over generations. Only a restricted number of species show behavioural adaptations that make them thrive in severely disturbed environments. Hence, rapid human-induced disturbances often decrease the diversity of native species, while facilitating the spread of invasive species with highly plastic behaviours. Consequently, behavioural responses to human-induced environmental change can have profound effects on the distribution, adaptation, speciation and extinction of populations and, hence, on biodiversity. A better understanding of the mechanisms of behavioural responses and their causes and consequences could improve our ability to predict the effects of human-induced environmental change on individual species and on biodiversity. © 2010 The Authors. Biological Reviews © 2010 Cambridge Philosophical Society.

Water availability in +2°C and +4°C worlds.

PubMed

Fung, Fai; Lopez, Ana; New, Mark

2011-01-13

While the parties to the UNFCCC agreed in the December 2009 Copenhagen Accord that a 2°C global warming over pre-industrial levels should be avoided, current commitments on greenhouse gas emissions reductions from these same parties will lead to a 50 : 50 chance of warming greater than 3.5°C. Here, we evaluate the differences in impacts and adaptation issues for water resources in worlds corresponding to the policy objective (+2°C) and possible reality (+4°C). We simulate the differences in impacts on surface run-off and water resource availability using a global hydrological model driven by ensembles of climate models with global temperature increases of 2°C and 4°C. We combine these with UN-based population growth scenarios to explore the relative importance of population change and climate change for water availability. We find that the projected changes in global surface run-off from the ensemble show an increase in spatial coherence and magnitude for a +4°C world compared with a +2°C one. In a +2°C world, population growth in most large river basins tends to override climate change as a driver of water stress, while in a +4°C world, climate change becomes more dominant, even compensating for population effects where climate change increases run-off. However, in some basins where climate change has positive effects, the seasonality of surface run-off becomes increasingly amplified in a +4°C climate.

Contrasting effects of temperature and precipitation change on amphibian phenology, abundance and performance.

PubMed

Ficetola, Gentile Francesco; Maiorano, Luigi

2016-07-01

Climate change is determining a generalized phenological advancement, and amphibians are among the taxa showing the strongest phenological responsiveness to warming temperatures. Amphibians are strongly influenced by climate change, but we do not have a clear picture of how climate influences important parameters of amphibian populations, such as abundance, survival, breeding success and morphology. Furthermore, the relative impact of temperature and precipitation change remains underappreciated. We used Bayesian meta-analysis and meta-regression to quantify the impact of temperature and precipitation change on amphibian phenology, abundance, individual features and performance. We obtained effect sizes from studies performed in five continents. Temperature increase was the major driver of phenological advancement, while the impact of precipitation on phenology was weak. Conversely, population dynamics was mostly determined by precipitation: negative trends were associated with drying regimes. The impact of precipitation on abundance was particularly strong in tropical areas, while the importance of temperature was feeble. Both temperature and precipitation influenced parameters representing breeding performance, morphology, developmental rate and survival, but the response was highly heterogeneous among species. For instance, warming temperature increased body size in some species, and decreased size in others. Similarly, rainy periods increased survival of some species and reduced the survival of others. Our study showed contrasting impacts of temperature and precipitation changes on amphibian populations. Both climatic parameters strongly influenced amphibian performance, but temperature was the major determinant of the phenological changes, while precipitation had the major role on population dynamics, with alarming declines associated with drying trends.

Range-wide effects of breeding- and nonbreeding-season climate on the abundance of a Neotropical migrant songbird.

PubMed

Wilson, Scott; LaDeau, Shannon L; Tøttrup, Anders P; Marra, Peter P

2011-09-01

Geographic variation in the population dynamics of a species can result from regional variability in climate and how it affects reproduction and survival. Identifying such effects for migratory birds requires the integration of population models with knowledge of migratory connectivity between breeding and nonbreeding areas. We used Bayesian hierarchical models with 26 years of Breeding Bird Survey data (1982-2007) to investigate the impacts of breeding- and nonbreeding-season climate on abundance of American Redstarts (Setophaga ruticilla) across the species range. We focused on 15 populations defined by Bird Conservation Regions, and we included variation across routes and observers as well as temporal trends and climate effects. American Redstart populations that breed in eastern North America showed increased abundance following winters with higher plant productivity in the Caribbean where they are expected to overwinter. In contrast, western breeding populations showed little response to conditions in their expected wintering areas in west Mexico, perhaps reflecting lower migratory connectivity or differential effects of winter rainfall on individuals across the species range. Unlike the case with winter climate, we found few effects of temperature prior to arrival in spring (March-April) or during the nesting period (May-June) on abundance the following year. Eight populations showed significant changes in abundance, with the steepest declines in the Atlantic Northern Forest (-3.4%/yr) and the greatest increases in the Prairie Hardwood Transition (4%/yr). This study emphasizes how the effects of climate on populations of migratory birds are context dependent and can vary depending on geographic location and the period of the annual cycle. Such knowledge is essential for predicting regional variation in how populations of a species might vary in their response to climate change.

The Long-Term Relationship between Population Growth and Vegetation Cover: An Empirical Analysis Based on the Panel Data of 21 Cities in Guangdong Province, China

PubMed Central

Li, Chao; Kuang, Yaoqiu; Huang, Ningsheng; Zhang, Chao

2013-01-01

It is generally believed that there is an inverse relationship between population growth and vegetation cover. However, reports about vegetation protection and reforestation around the World have been continuously increasing in recent decades, which seems to indicate that this relationship may not be true. In this paper, we have taken 21 cities in Guangdong Province, China as the study area to test the long-term relationship between population growth and vegetation cover, using an AVHRR NDVI data set and the panel cointegrated regression method. The results show that there is a long-term inverted N-shaped curve relationship between population growth and vegetation cover in the region where there are frequent human activities and the influence of climate change on vegetation cover changes is relatively small. The two turning points of the inverted N-shaped curve for the case of Guangdong Province correspond to 2,200 persons·km−2 and 3,820 persons·km−2, and they can provide a reference range for similar regions of the World. It also states that the population urbanization may have a negative impact on the vegetation cover at the early stage, but have a positive impact at the later stage. In addition, the Panel Error Correction Model (PECM) is used to investigate the causality direction between population growth and vegetation cover. The results show that not only will the consuming destruction effect and planting construction effect induced by the population growth have a great impact on vegetation cover changes, but vegetation cover changes in turn will also affect the population growth in the long term. PMID:23435589

Change-in-ratio methods for estimating population size

USGS Publications Warehouse

Udevitz, Mark S.; Pollock, Kenneth H.; McCullough, Dale R.; Barrett, Reginald H.

2002-01-01

Change-in-ratio (CIR) methods can provide an effective, low cost approach for estimating the size of wildlife populations. They rely on being able to observe changes in proportions of population subclasses that result from the removal of a known number of individuals from the population. These methods were first introduced in the 1940’s to estimate the size of populations with 2 subclasses under the assumption of equal subclass encounter probabilities. Over the next 40 years, closed population CIR models were developed to consider additional subclasses and use additional sampling periods. Models with assumptions about how encounter probabilities vary over time, rather than between subclasses, also received some attention. Recently, all of these CIR models have been shown to be special cases of a more general model. Under the general model, information from additional samples can be used to test assumptions about the encounter probabilities and to provide estimates of subclass sizes under relaxations of these assumptions. These developments have greatly extended the applicability of the methods. CIR methods are attractive because they do not require the marking of individuals, and subclass proportions often can be estimated with relatively simple sampling procedures. However, CIR methods require a carefully monitored removal of individuals from the population, and the estimates will be of poor quality unless the removals induce substantial changes in subclass proportions. In this paper, we review the state of the art for closed population estimation with CIR methods. Our emphasis is on the assumptions of CIR methods and on identifying situations where these methods are likely to be effective. We also identify some important areas for future CIR research.

Direct and indirect effects of climate change on a prairie plant community.

PubMed

Adler, Peter B; Leiker, James; Levine, Jonathan M

2009-09-03

Climate change directly affects species by altering their physical environment and indirectly affects species by altering interspecific interactions such as predation and competition. Recent studies have shown that the indirect effects of climate change may amplify or counteract the direct effects. However, little is known about the the relative strength of direct and indirect effects or their potential to impact population persistence. We studied the effects of altered precipitation and interspecific interactions on the low-density tiller growth rates and biomass production of three perennial grass species in a Kansas, USA mixed prairie. We transplanted plugs of each species into local neighborhoods of heterospecific competitors and then exposed the plugs to a factorial manipulation of growing season precipitation and neighbor removal. Precipitation treatments had significant direct effects on two of the three species. Interspecific competition also had strong effects, reducing low-density tiller growth rates and aboveground biomass production for all three species. In fact, in the presence of competitors, (log) tiller growth rates were close to or below zero for all three species. However, we found no convincing evidence that per capita competitive effects changed with precipitation, as shown by a lack of significant precipitation x competition interactions. We found little evidence that altered precipitation will influence per capita competitive effects. However, based on species' very low growth rates in the presence of competitors in some precipitation treatments, interspecific interactions appear strong enough to affect the balance between population persistence and local extinction. Therefore, ecological forecasting models should include the effect of interspecific interactions on population growth, even if such interaction coefficients are treated as constants.

Global health and climate change: moving from denial and catastrophic fatalism to positive action.

PubMed

Costello, Anthony; Maslin, Mark; Montgomery, Hugh; Johnson, Anne M; Ekins, Paul

2011-05-13

The health effects of climate change have had relatively little attention from climate scientists and governments. Climate change will be a major threat to population health in the current century through its potential effects on communicable disease, heat stress, food and water security, extreme weather events, vulnerable shelter and population migration. This paper addresses three health-sector strategies to manage the health effects of climate change-promotion of mitigation, tackling the pathways that lead to ill-health and strengthening health systems. Mitigation of greenhouse gas (GHG) emissions is affordable, and low-carbon technologies are available now or will be in the near future. Pathways to ill-health can be managed through better information, poverty reduction, technological innovation, social and cultural change and greater coordination of national and international institutions. Strengthening health systems requires increased investment in order to provide effective public health responses to climate-induced threats to health, equitable treatment of illness, promotion of low-carbon lifestyles and renewable energy solutions within health facilities. Mitigation and adaptation strategies will produce substantial benefits for health, such as reductions in obesity and heart disease, diabetes, stress and depression, pneumonia and asthma, as well as potential cost savings within the health sector. The case for mitigating climate change by reducing GHGs is overwhelming. The need to build population resilience to the global health threat from already unavoidable climate change is real and urgent. Action must not be delayed by contrarians, nor by catastrophic fatalists who say it is all too late. © 2011 Royal Society

Density-Dependent Effects on Group Size Are Sex-Specific in a Gregarious Ungulate

PubMed Central

Vander Wal, Eric; van Beest, Floris M.; Brook, Ryan K.

2013-01-01

Density dependence can have marked effects on social behaviors such as group size. We tested whether changes in population density of a large herbivore (elk, Cervus canadensis) affected sex-specific group size and whether the response was density- or frequency-dependent. We quantified the probability and strength of changes in group sizes and dispersion as population density changed for each sex. We used group size data from a population of elk in Manitoba, Canada, that was experimentally reduced from 1.20 to 0.67 elk/km2 between 2002 and 2009. Our results indicated that functional responses of group size to population density are sex-specific. Females showed a positive density-dependent response in group size at population densities ≥0.70 elk/km2 and we found evidence for a minimum group size at population density ≤0.70 elk/km2. Changes in male group size were also density-dependent; however, the strength of the relationship was lower than for females. Density dependence in male group size was predominantly a result of fusion of solitary males into larger groups, rather than fusion among existing groups. Our study revealed that density affects group size of a large herbivore differently between males and females, which has important implications for the benefits e.g., alleviating predation risk, and costs of social behaviors e.g., competition for resources and mates, and intra-specific pathogen transmission. PMID:23326502

Effect of baseline plasma fatty acids on eicosapentaenoic acid levels in individuals supplemented with alpha-linolenic acid.

PubMed

DeFilippis, Andrew P; Harper, Charles R; Cotsonis, George A; Jacobson, Terry A

2009-01-01

We previously reported a >50% increase in mean plasma eicosapentaenoic acid levels in a general medicine clinic population after supplementation with alpha-linolenic acid. In the current analysis, we evaluate the variability of changes in eicosapentaenoic acid levels among individuals supplemented with alpha-linolenic acid and evaluated the impact of baseline plasma fatty acids levels on changes in eicosapentaenoic acid levels in these individuals. Changes in eicosapentaenoic acid levels among individuals supplemented with alpha-linolenic acid ranged from a 55% decrease to a 967% increase. Baseline plasma fatty acids had no statistically significant effect on changes in eicosapentaenoic levels acid after alpha-linolenic acid supplementation. Changes in eicosapentaenoic acid levels varied considerably in a general internal medicine clinic population supplemented with alpha-linolenic acid. Factors that may impact changes in plasma eicosapentaenoic acid levels after alpha-linolenic acid supplementation warrant further study.

Fish population modeling approaches for assessing direct effects and recovery following mitigation of a pulp mill effluent in Jackfish Bay

EPA Science Inventory

We present an approach to link chemically-induced alterations in molecular and biochemical endpoints to adverse outcomes in whole organisms and populations. A predictive population model was developed to translate changes in fecundity measures of white sucker (Catostomus commers...

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

USDA-ARS?s Scientific Manuscript database

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

Measuring the burden of disease due to climate change and developing a forecast model in South Korea.

PubMed

Yoon, S-J; Oh, I-H; Seo, H-Y; Kim, E-J

2014-08-01

Climate change influences human health in various ways, and quantitative assessments of the effect of climate change on health at national level are becoming essential for environmental health management. This study quantified the burden of disease attributable to climate change in Korea using disability-adjusted life years (DALY), and projected how this would change over time. Diseases related to climate change in Korea were selected, and meteorological data for each risk factor of climate change were collected. Mortality was calculated, and a database of incidence and prevalence was established. After measuring the burden of each disease, the total burden of disease related to climate change was assessed by multiplying population-attributable fractions. Finally, an estimation model for the burden of disease was built based on Korean climate data. The total burden of disease related to climate change in Korea was 6.85 DALY/1000 population in 2008. Cerebrovascular diseases induced by heat waves accounted for 72.1% of the total burden of disease (hypertensive disease 1.82 DALY/1000 population, ischaemic heart disease 1.56 DALY/1000 population, cerebrovascular disease 1.56 DALY/1000 population). According to the estimation model, the total burden of disease will be 11.48 DALY/1000 population in 2100, which is twice the total burden of disease in 2008. This study quantified the burden of disease caused by climate change in Korea, and provides valuable information for determining the priorities of environmental health policy in East Asian countries with similar climates. Copyright © 2014 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

What does testosterone do for red deer males?

PubMed Central

Malo, A.F.; Roldan, E.R.S.; Garde, J.J.; Soler, A.J.; Vicente, J.; Gortazar, C.; Gomendio, M.

2008-01-01

Testosterone has been proposed to have a dual effect, enhancing sexual traits while depressing parasite resistance in males. Here, we test this hypothesis in red deer, examining males from captive populations during the whole annual cycle and males from natural populations during the breeding season. We first explored the effects of body size, age and sampling date on testosterone to avoid confounding effects. Our results show that in captive populations seasonal changes in testosterone levels were mirrored by changes in testes size, and that during the rut there was a strong correlation between both. In natural populations, males with higher testosterone levels had larger testes, improved sperm quality, smaller burr diameter, stronger antlers, higher haematocrit levels, and increased nematode parasite load. By contrast, no significant relationship was found between testosterone and spleen size or tick parasite load. We conclude that testosterone (i) improves males' reproductive investment and physical stamina, (ii) improves antler strength but reduces burr diameter, and (iii) imposes a cost in terms of depressed parasite resistance. PMID:19129132

Mathematics and mallard management

USGS Publications Warehouse

Cowardin, L.M.; Johnson, D.H.

1979-01-01

Waterfowl managers can effectively use simple population models to aid in making management decisions. We present a basic model of the change in population size as related to survival and recruitment. A management technique designed to increase survival of mallards (Anas platyrhynchos) by limiting harvest on the Chippewa National Forest, Minnesota, is used to illustrate the application of models in decision making. The analysis suggests that the management technique would be of limited effectiveness. In a 2nd example, the change in mallard population in central North Dakota is related to implementing programs to create dense nesting cover with or without supplementary predator control. The analysis suggests that large tracts of land would be required to achieve a hypothetical management objective of increasing harvest by 50% while maintaining a stable population. Less land would be required if predator reduction were used in combination with cover management, but questions about effectiveness and ecological implications of large scale predator reduction remain unresolved. The use of models as a guide to planning research responsive to the needs of management is illustrated.

Fine-Scale Genetic Response to Landscape Change in a Gliding Mammal

PubMed Central

Goldingay, Ross L.; Harrisson, Katherine A.; Taylor, Andrea C.; Ball, Tina M.; Sharpe, David J.; Taylor, Brendan D.

2013-01-01

Understanding how populations respond to habitat loss is central to conserving biodiversity. Population genetic approaches enable the identification of the symptoms of population disruption in advance of population collapse. However, the spatio-temporal scales at which population disruption occurs are still too poorly known to effectively conserve biodiversity in the face of human-induced landscape change. We employed microsatellite analysis to examine genetic structure and diversity over small spatial (mostly 1-50 km) and temporal scales (20-50 years) in the squirrel glider (Petaurus norfolcensis), a gliding mammal that is commonly subjected to a loss of habitat connectivity. We identified genetically differentiated local populations over distances as little as 3 km and within 30 years of landscape change. Genetically isolated local populations experienced the loss of genetic diversity, and significantly increased mean relatedness, which suggests increased inbreeding. Where tree cover remained, genetic differentiation was less evident. This pattern was repeated in two landscapes located 750 km apart. These results lend support to other recent studies that suggest the loss of habitat connectivity can produce fine-scale population genetic change in a range of taxa. This gives rise to the prediction that many other vertebrates will experience similar genetic changes. Our results suggest the future collapse of local populations of this gliding mammal is likely unless habitat connectivity is maintained or restored. Landscape management must occur on a fine-scale to avert the erosion of biodiversity. PMID:24386079

The effects of country-level population policy for enhancing adaptation to climate change

NASA Astrophysics Data System (ADS)

Gunasekara, N. K.; Kazama, S.; Yamazaki, D.; Oki, T.

2013-11-01

The effectiveness of population policy in reducing the combined impacts of population change and climate change on water resources is explored. One no-policy scenario and two scenarios with population policy assumptions are employed in combination with water availability under the SRES scenarios A1b, B1 and A2 for the impact analysis. The population data used are from the World Bank. The river discharges per grid of horizontal resolution 0.5° are obtained from the Total Runoff Integrating Pathways (TRIP) of the University of Tokyo, Japan. Unlike the population scenarios utilized in the SRES emission scenarios and the newest representative concentration pathways, the scenarios employed in this research are based, even after 2050, on country-level rather than regional-level growth assumptions. Our analysis implies that the heterogeneous pattern of population changes across the world is the dominant driver of water stress, irrespective of future greenhouse gas emissions, with highest impacts occurring in the already water-stressed low latitudes. In 2100, Africa, Middle East and parts of Asia are under extreme water stress under all scenarios. The sensitivity analysis reveals that a small reduction in populations over the region could relieve a large number of people from high water stress, while a further increase in population from the assumed levels (SC1) might not increase the number of people under high water stress considerably. Most of the population increase towards 2100 occurs in the already water-stressed lower latitudes. Therefore, population reduction policies are recommended for this region as a method of adaptation to the future water stress conditions. Population reduction policies will facilitate more control over their future development pathways, even if these countries were not able to contribute significantly to greenhouse gas (GHG) emission cuts due to economic constraints. However, for the European region, the population living in water-stressed regions is almost 20 times lower than that in the lower latitudes. For countries with high population momentum, the population policy scenario with fertility-reduction assumptions gained a maximum of 6.1 times the water availability in Niger and 5.3 times that in Uganda compared with the no-policy scenario. Most of these countries are in sub-Saharan Africa. These countries represent 24.5% of the global population in the no-policy scenario, and the scenario with fertility-reduction assumptions reduces it to 8.7% by 2100. This scenario is also effective in reducing the area under extreme water stress in these countries. However, the policy scenario with assumptions of population stabilization at the replacement fertility rate increases the water stress in high-latitude countries. Nevertheless, the impact is low due to the high per capita water availability in the region. This research is expected to widen the understanding of the combined impacts of climate change in the future and of the strategies needed to enhance the space for adaptation.

Effects of environmental covariates and density on the catchability of fish populations and interpretation of catch per unit effort trends

USGS Publications Warehouse

Korman, Josh; Yard, Mike

2017-01-01

Article for outlet: Fisheries Research. Abstract: Quantifying temporal and spatial trends in abundance or relative abundance is required to evaluate effects of harvest and changes in habitat for exploited and endangered fish populations. In many cases, the proportion of the population or stock that is captured (catchability or capture probability) is unknown but is often assumed to be constant over space and time. We used data from a large-scale mark-recapture study to evaluate the extent of spatial and temporal variation, and the effects of fish density, fish size, and environmental covariates, on the capture probability of rainbow trout (Oncorhynchus mykiss) in the Colorado River, AZ. Estimates of capture probability for boat electrofishing varied 5-fold across five reaches, 2.8-fold across the range of fish densities that were encountered, 2.1-fold over 19 trips, and 1.6-fold over five fish size classes. Shoreline angle and turbidity were the best covariates explaining variation in capture probability across reaches and trips. Patterns in capture probability were driven by changes in gear efficiency and spatial aggregation, but the latter was more important. Failure to account for effects of fish density on capture probability when translating a historical catch per unit effort time series into a time series of abundance, led to 2.5-fold underestimation of the maximum extent of variation in abundance over the period of record, and resulted in unreliable estimates of relative change in critical years. Catch per unit effort surveys have utility for monitoring long-term trends in relative abundance, but are too imprecise and potentially biased to evaluate population response to habitat changes or to modest changes in fishing effort.

Small-scale fisheries, population dynamics, and resource use in Africa: the case of Moree, Ghana.

PubMed

Marquette, Catherine M; Koranteng, Kwame A; Overå, Ragnhild; Aryeetey, Ellen Bortei-Doku

2002-06-01

We consider population dynamics and sustainable use and development of fishery resources in Moree, a small-scale fishing and coastal community of 20,000 people in the Central Region of Ghana near Cape Coast. Moree suggests that relationships between population dynamics and fishery resources are more complex than the concept of Malthusian overfishing implies. Reasons include changing biophysical characteristics of the upwelling system along the coast of West Africa; qualitative as well as quantitative changes in fishing activity throughout the year; the market nature of fishing activity and nonlocal demands for fish; regular fishery migration; and institutions regulating fishery resource access at home and at migration destinations. Population and resource relationships in Moree may be the effects of fishery resource and economic changes on migration rather than population pressure on fishery resources. Fisheries management policies must take into account processes that lie beyond the influence of local fishermen.

Shifting species interactions in terrestrial dryland ecosystems under altered water availability and climate change.

PubMed

McCluney, Kevin E; Belnap, Jayne; Collins, Scott L; González, Angélica L; Hagen, Elizabeth M; Nathaniel Holland, J; Kotler, Burt P; Maestre, Fernando T; Smith, Stanley D; Wolf, Blair O

2012-08-01

Species interactions play key roles in linking the responses of populations, communities, and ecosystems to environmental change. For instance, species interactions are an important determinant of the complexity of changes in trophic biomass with variation in resources. Water resources are a major driver of terrestrial ecology and climate change is expected to greatly alter the distribution of this critical resource. While previous studies have documented strong effects of global environmental change on species interactions in general, responses can vary from region to region. Dryland ecosystems occupy more than one-third of the Earth's land mass, are greatly affected by changes in water availability, and are predicted to be hotspots of climate change. Thus, it is imperative to understand the effects of environmental change on these globally significant ecosystems. Here, we review studies of the responses of population-level plant-plant, plant-herbivore, and predator-prey interactions to changes in water availability in dryland environments in order to develop new hypotheses and predictions to guide future research. To help explain patterns of interaction outcomes, we developed a conceptual model that views interaction outcomes as shifting between (1) competition and facilitation (plant-plant), (2) herbivory, neutralism, or mutualism (plant-herbivore), or (3) neutralism and predation (predator-prey), as water availability crosses physiological, behavioural, or population-density thresholds. We link our conceptual model to hypothetical scenarios of current and future water availability to make testable predictions about the influence of changes in water availability on species interactions. We also examine potential implications of our conceptual model for the relative importance of top-down effects and the linearity of patterns of change in trophic biomass with changes in water availability. Finally, we highlight key research needs and some possible broader impacts of our findings. Overall, we hope to stimulate and guide future research that links changes in water availability to patterns of species interactions and the dynamics of populations and communities in dryland ecosystems. © 2011 The Authors. Biological Reviews © 2011 Cambridge Philosophical Society.

The threat of climate change to freshwater pearl mussel populations.

PubMed

Hastie, Lee C; Cosgrove, Peter J; Ellis, Noranne; Gaywood, Martin J

2003-02-01

Changes in climate are occurring around the world and the effects on ecosystems will vary, depending on the extent and nature of these changes. In northern Europe, experts predict that annual rainfall will increase significantly, along with dramatic storm events and flooding in the next 50-100 years. Scotland is a stronghold of the endangered freshwater pearl mussel, Margaritifera margaritifera (L.), and a number of populations may be threatened. For example, large floods have been shown to adversely affect mussels, and although these stochastic events were historically rare, they may now be occurring more often as a result of climate change. Populations may also be affected by a number of other factors, including predicted changes in temperature, sea level, habitat availability, host fish stocks and human activity. In this paper, we explain how climate change may impact M. margaritifera and discuss the general implications for the conservation management of this species.

Targeted mass media interventions promoting healthy behaviours to reduce risk of non-communicable diseases in adult, ethnic minorities.

PubMed

Mosdøl, Annhild; Lidal, Ingeborg B; Straumann, Gyri H; Vist, Gunn E

2017-02-17

Physical activity, a balanced diet, avoidance of tobacco exposure, and limited alcohol consumption may reduce morbidity and mortality from non-communicable diseases (NCDs). Mass media interventions are commonly used to encourage healthier behaviours in population groups. It is unclear whether targeted mass media interventions for ethnic minority groups are more or less effective in changing behaviours than those developed for the general population. To determine the effects of mass media interventions targeting adult ethnic minorities with messages about physical activity, dietary patterns, tobacco use or alcohol consumption to reduce the risk of NCDs. We searched CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, ERIC, SweMed+, and ISI Web of Science until August 2016. We also searched for grey literature in OpenGrey, Grey Literature Report, Eldis, and two relevant websites until October 2016. The searches were not restricted by language. We searched for individual and cluster-randomised controlled trials, controlled before-and-after studies (CBA) and interrupted time series studies (ITS). Relevant interventions promoted healthier behaviours related to physical activity, dietary patterns, tobacco use or alcohol consumption; were disseminated via mass media channels; and targeted ethnic minority groups. The population of interest comprised adults (≥ 18 years) from ethnic minority groups in the focal countries. Primary outcomes included indicators of behavioural change, self-reported behavioural change and knowledge and attitudes towards change. Secondary outcomes were the use of health promotion services and costs related to the project. Two authors independently reviewed the references to identify studies for inclusion. We extracted data and assessed the risk of bias in all included studies. We did not pool the results due to heterogeneity in comparisons made, outcomes, and study designs. We describe the results narratively and present them in 'Summary of findings' tables. We judged the quality of the evidence using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) methodology. Six studies met the inclusion criteria, including three RCTs, two cluster-RCTs and one ITS. All were conducted in the USA and comprised targeted mass media interventions for people of African descent (four studies), Spanish-language dominant Latino immigrants (one study), and Chinese immigrants (one study). The two latter studies offered the intervention in the participants' first language (Spanish, Cantonese, or Mandarin). Three interventions targeted towards women only, one pregnant women specifically. We judged all studies as being at unclear risk of bias in at least one domain and three studies as being at high risk of bias in at least one domain.We categorised the findings into three comparisons. The first comparison examined mass media interventions targeted at ethnic minorities versus an equivalent mass media intervention intended for the general population. The one study in this category (255 participants of African decent) found little or no difference in effect on self-reported behavioural change for smoking and only small differences in attitudes to change between participants who were given a culturally specific smoking cessation booklet versus a booklet intended for the general population. We are uncertain about the effect estimates, as assessed by the GRADE methodology (very low quality evidence of effect). No study provided data for indicators of behavioural change or adverse effects.The second comparison assessed targeted mass media interventions versus no intervention. One study (154 participants of African decent) reported effects for our primary outcomes. Participants in the intervention group had access to 12 one-hour live programmes on cable TV and received print material over three months regarding nutrition and physical activity to improve health and weight control. Change in body mass index (BMI) was comparable between groups 12 months after the baseline (low quality evidence). Scores on a food habits (fat behaviours) and total leisure activity scores changed favourably for the intervention group (very low quality evidence). Two other studies exposed entire populations in geographical areas to radio advertisements targeted towards African American communities. Authors presented effects on two of our secondary outcomes, use of health promotion services and project costs. The campaign message was to call smoking quit lines. The outcome was the number of calls received. After one year, one study reported 18 calls per estimated 10,000 targeted smokers from the intervention communities (estimated target population 310,500 persons), compared to 0.2 calls per estimated 10,000 targeted smokers from the control communities (estimated target population 331,400 persons) (moderate quality evidence). The ITS study also reported an increase in the number of calls from the target population during campaigns (low quality evidence). The proportion of African American callers increased in both studies (low to very low quality evidence). No study provided data on knowledge and attitudes for change and adverse effects. Information on costs were sparse.The third comparison assessed targeted mass media interventions versus a mass media intervention plus personalised content. Findings are based on three studies (1361 participants). Participants in these comparison groups received personal feedback. Two of the studies recorded weight changes over time. Neither found significant differences between the groups (low quality evidence). Evidence on behavioural changes, and knowledge and attitudes typically found some effects in favour of receiving personalised content or no significant differences between groups (very low quality evidence). No study provided data on adverse effects. Information on costs were sparse. The available evidence is inadequate for understanding whether mass media interventions targeted toward ethnic minority populations are more effective in changing health behaviours than mass media interventions intended for the population at large. When compared to no intervention, a targeted mass media intervention may increase the number of calls to smoking quit line, but the effect on health behaviours is unclear. These studies could not distinguish the impact of different components, for instance the effect of hearing a message regarding behavioural change, the cultural adaptation to the ethnic minority group, or increase reach to the target group through more appropriate mass media channels. New studies should explore targeted interventions for ethnic minorities with a first language other than the dominant language in their resident country, as well as directly compare targeted versus general population mass media interventions.

Effectiveness of the mHealth technology in improvement of healthy behaviors in an elderly population-a systematic review.

PubMed

Changizi, Maryam; Kaveh, Mohammad H

2017-01-01

Demographic changes in the 21st century, increased population of the elderly and high prevalence of related diseases call for new healthcare strategies that can change the behavior and lifestyle of elderly individuals. Innovative information and communication technology, such as mobile health (mHealth), can play a significant role. The present study was conducted aiming to assess the effectiveness of mHealth in improving health behaviors among an elderly population. This paper presents a systematic review involving a search of PubMed, Web of Science (ISI), Scopus, Science Direct and Embase databases from [2012-2016]. Our search resulted after initial evaluations 12 articles. Inclusion criteria mostly revolved around interventional studies, other studies were excluded because of their methodology, non-elderly target groups and irrelevant to the subject. Findings showed that mHealth can improve care, self-management, self-efficacy, behavior promotion (quality of sleep, diet, physical activity mental health) and medication adherence. The mHealth technology has proven effective for disease prevention, lifestyle changes, management of cardiovascular disease and diabetes, and is a suitable tool for elderly people. In conclusion, it seems that mHealth can facilitate behavioral changes; although, further research is necessary in this regard.

Comparing the effects of food restriction and overeating on brain reward systems.

PubMed

Avena, Nicole M; Murray, Susan; Gold, Mark S

2013-10-01

Both caloric restriction and overeating have been shown to affect neural processes associated with reinforcement. Both preclinical and some clinical studies have provided evidence that food restriction may increase reward sensitivity, and while there are mixed findings regarding the effects of overeating on reward sensitivity, there is strong evidence linking this behavior with changes in reward-related brain regions. Evidence of these changes comes in part from findings that show that such eating patterns are associated with increased drug use. The data discussed here regarding the differential effects of various eating patterns on reward systems may be particularly relevant to the aging population, as this population has been shown to exhibit altered reward sensitivity and decreased caloric consumption. Moreover, members of this population appear to be increasingly affected by the current obesity epidemic. Food, like alcohol or drugs, can stimulate its own consumption and produce similar neurochemical changes in the brain. Age-related loss of appetite, decreased eating, and caloric restriction are hypothesized to be associated with changes in the prevalence of substance misuse, abuse, and dependence seen in this cohort. Copyright © 2013 Elsevier Inc. All rights reserved.

A comprehensive monitoring program for North American shorebirds

USGS Publications Warehouse

Howe, Marshall; Bart, Jon; Brown, Stephen; Elphick, Chris; Gill, Robert E.; Harrington, Brian A.; Hickey, Catherine; Morrison, Guy; Skagen, Susan K.; Warnock, Nils

2000-01-01

Anthropogenic changes to the biosphere, including widespread degradation and losses of habitats and ecosystems, are causing rapid and profound changes to bird and other wildlife populations throughout the world. Such changes have led to increasing risks and rates of extinction. As a consequence, information on how bird populations are changing is becoming increasingly important to wildlife conservationists and managers. Early detection of population change is crucial for setting wildlife planning and management priorities. For example, information on population size, population vulnerability, and population change has been central to international conservation strategies such as the Ramsar Convention, the Western Hemisphere (Bonn) Convention, and the Western Hemisphere Shorebird Reserve Network. Measuring population size or change is also crucial for evaluating the effectiveness of population management programs implemented by wildlife agencies both locally and regionally.Although the concept of determining population size is simple, practical difficulties can be enormous and costly to overcome. In the United States, $4 billion will be spent in year 2000 to census the human population, possibly one of the most easily counted of all vertebrates. By contrast, the portion of the FY 2000 budget of the U.S. Department of the Interior allotted for tracking populations of all migratory birds (> 600 species) is less than $5 million (.0125% of the human census figure). This falls far short of the amount required to provide adequate, science-based information about bird populations and population change to wildlife managers.The gap between current ability and need is especially noteworthy for shorebirds. There are 72 species, subspecies, or distinct populations of shorebirds in North America. Even though most of these have received less conservation attention than such groups as waterfowl, colonial waterbirds, or songbirds, recent independent evaluation of data collected for other purposes in the eastern United States and Canada during the 1970s and early 1980s showed that 16 of 26 species surveyed are apparently declining, some at rates exceeding 5% per year (Howe et al., 1989). Except for one increasing species, populations of the other 9 species were statistically unchanged over the time period analyzed. In most cases causes of shorebird population declines are poorly known. For some species, the declines may be part of natural population cycles. For others the changes may reflect deterioration of conditions on the nesting grounds, at migration stopover locations, in wintering zones, or combinations of these. Determining which of these scenarios is correct and what management actions, if any, are warranted will be possible only after implementing a comprehensive monitoring plan such as that described here

Education in a Changing Rural Environment: The Impact of Population and Economic Change on the Demand for and Costs of Public Education in Rural America. A Synthesis of Research Findings and an Identification of Important Policy Issues. SRDC Synthesis-Bibliography Series 18.

ERIC Educational Resources Information Center

Deaton, Brady J.; McNamara, Kevin T.

A synthesis of research findings addressing effects of population and economic changes on education supply and demand in rural communities also presents policy implications, to help with local decision making. Principal research findings listed include: lack of a statistical relationship between per pupil expenditures and achievement on…

Modeling effects of environmental change on wolf population dynamics, trait evolution, and life history.

PubMed

Coulson, Tim; MacNulty, Daniel R; Stahler, Daniel R; vonHoldt, Bridgett; Wayne, Robert K; Smith, Douglas W

2011-12-02

Environmental change has been observed to generate simultaneous responses in population dynamics, life history, gene frequencies, and morphology in a number of species. But how common are such eco-evolutionary responses to environmental change likely to be? Are they inevitable, or do they require a specific type of change? Can we accurately predict eco-evolutionary responses? We address these questions using theory and data from the study of Yellowstone wolves. We show that environmental change is expected to generate eco-evolutionary change, that changes in the average environment will affect wolves to a greater extent than changes in how variable it is, and that accurate prediction of the consequences of environmental change will probably prove elusive.

Outcrossed sex allows a selfish gene to invade yeast populations.

PubMed

Goddard, M R; Greig, D; Burt, A

2001-12-22

Homing endonuclease genes (HEGs) in eukaryotes are optional genes that have no obvious effect on host phenotype except for causing chromosomes not containing a copy of the gene to be cut, thus causing them to be inherited at a greater than Mendelian rate via gene conversion. These genes are therefore expected to increase in frequency in outcrossed populations, but not in obligately selfed populations. In order to test this idea, we compared the dynamics of the VDE HEG in six replicate outcrossed and inbred populations of yeast (Saccharomyces cerevisiae). VDE increased in frequency from 0.21 to 0.55 in four outcrossed generations, but showed no change in frequency in the inbred populations. The absence of change in the inbred populations indicates that any effect of VDE on mitotic replication rates is less than 1%. The data from the outcrossed populations best fit a model in which 82% of individuals are derived from outcrossing and VDE is inherited by 74% of the meiotic products from heterozygotes (as compared with 50% for Mendelian genes). These results empirically demonstrate how a host mating system plays a key role in determining the population dynamics of a selfish gene.

Outcrossed sex allows a selfish gene to invade yeast populations.

PubMed Central

Goddard, M. R.; Greig, D.; Burt, A.

2001-01-01

Homing endonuclease genes (HEGs) in eukaryotes are optional genes that have no obvious effect on host phenotype except for causing chromosomes not containing a copy of the gene to be cut, thus causing them to be inherited at a greater than Mendelian rate via gene conversion. These genes are therefore expected to increase in frequency in outcrossed populations, but not in obligately selfed populations. In order to test this idea, we compared the dynamics of the VDE HEG in six replicate outcrossed and inbred populations of yeast (Saccharomyces cerevisiae). VDE increased in frequency from 0.21 to 0.55 in four outcrossed generations, but showed no change in frequency in the inbred populations. The absence of change in the inbred populations indicates that any effect of VDE on mitotic replication rates is less than 1%. The data from the outcrossed populations best fit a model in which 82% of individuals are derived from outcrossing and VDE is inherited by 74% of the meiotic products from heterozygotes (as compared with 50% for Mendelian genes). These results empirically demonstrate how a host mating system plays a key role in determining the population dynamics of a selfish gene. PMID:11749707

Spatio-temporal population structuring and genetic diversity retention in depleted Atlantic Bluefin tuna of the Mediterranean Sea

PubMed Central

Riccioni, Giulia; Landi, Monica; Ferrara, Giorgia; Milano, Ilaria; Cariani, Alessia; Zane, Lorenzo; Sella, Massimo; Barbujani, Guido; Tinti, Fausto

2010-01-01

Fishery genetics have greatly changed our understanding of population dynamics and structuring in marine fish. In this study, we show that the Atlantic Bluefin tuna (ABFT, Thunnus thynnus), an oceanic predatory species exhibiting highly migratory behavior, large population size, and high potential for dispersal during early life stages, displays significant genetic differences over space and time, both at the fine and large scales of variation. We compared microsatellite variation of contemporary (n = 256) and historical (n = 99) biological samples of ABFTs of the central-western Mediterranean Sea, the latter dating back to the early 20th century. Measures of genetic differentiation and a general heterozygote deficit suggest that differences exist among population samples, both now and 96–80 years ago. Thus, ABFTs do not represent a single panmictic population in the Mediterranean Sea. Statistics designed to infer changes in population size, both from current and past genetic variation, suggest that some Mediterranean ABFT populations, although still not severely reduced in their genetic potential, might have suffered from demographic declines. The short-term estimates of effective population size are straddled on the minimum threshold (effective population size = 500) indicated to maintain genetic diversity and evolutionary potential across several generations in natural populations. PMID:20080643

Estimating Effects of Species Interactions on Populations of Endangered Species.

PubMed

Roth, Tobias; Bühler, Christoph; Amrhein, Valentin

2016-04-01

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

Climate change impact on microclimate of work environment related to occupational health and productivity.

PubMed

Marchetti, Enrico; Capone, Pasquale; Freda, Daniela

2016-01-01

Climate change is a global emergency that influences human health and occupational safety. Global warming characterized by an increase in temperature of the ambience and humidity affects human health directly impairing body thermoregulation with serious consequences: dehydration, fatigue, heat stroke and even death. Several studies have demonstrated negative effects of climate change on working populations in a wide variety of workplaces with particular regard to outdoor and uncooled indoor workplaces. Most vulnerable workers are outdoor workers in tropical and subtropical countries usually involved in heavy labor during hot seasons. Many of the consequences therefore, regarding working people are possible, even without health symptoms by reducing work productivity. The scope of this review is to investigate effects of climate change on workers both in relation to health and work productivity. This study has been realized by analyzing recent international literature. In order to reduce negative effects of climate change on working populations it is essential to implement preventive measures with a multidisciplinary strategy limiting health risks and improving work productivity.

Contrasted demographic responses facing future climate change in Southern Ocean seabirds.

PubMed

Barbraud, Christophe; Rivalan, Philippe; Inchausti, Pablo; Nevoux, Marie; Rolland, Virginie; Weimerskirch, Henri

2011-01-01

1. Recent climate change has affected a wide range of species, but predicting population responses to projected climate change using population dynamics theory and models remains challenging, and very few attempts have been made. The Southern Ocean sea surface temperature and sea ice extent are projected to warm and shrink as concentrations of atmospheric greenhouse gases increase, and several top predator species are affected by fluctuations in these oceanographic variables. 2. We compared and projected the population responses of three seabird species living in sub-tropical, sub-Antarctic and Antarctic biomes to predicted climate change over the next 50 years. Using stochastic population models we combined long-term demographic datasets and projections of sea surface temperature and sea ice extent for three different IPCC emission scenarios (from most to least severe: A1B, A2, B1) from general circulation models of Earth's climate. 3. We found that climate mostly affected the probability to breed successfully, and in one case adult survival. Interestingly, frequent nonlinear relationships in demographic responses to climate were detected. Models forced by future predicted climatic change provided contrasted population responses depending on the species considered. The northernmost distributed species was predicted to be little affected by a future warming of the Southern Ocean, whereas steep declines were projected for the more southerly distributed species due to sea surface temperature warming and decrease in sea ice extent. For the most southerly distributed species, the A1B and B1 emission scenarios were respectively the most and less damaging. For the two other species, population responses were similar for all emission scenarios. 4. This is among the first attempts to study the demographic responses for several populations with contrasted environmental conditions, which illustrates that investigating the effects of climate change on core population dynamics is feasible for different populations using a common methodological framework. Our approach was limited to single populations and have neglected population settlement in new favourable habitats or changes in inter-specific relations as a potential response to future climate change. Predictions may be enhanced by merging demographic population models and climatic envelope models. © 2010 The Authors. Journal compilation © 2010 British Ecological Society.

Projecting pest population dynamics under global warming: the combined effect of inter- and intra-annual variations.

PubMed

Zidon, Royi; Tsueda, Hirotsugu; Morin, Efrat; Morin, Shai

2016-06-01

The typical short generation length of insects makes their population dynamics highly sensitive not only to mean annual temperatures but also to their intra-annual variations. To consider the combined effect of both thermal factors under global warming, we propose a modeling framework that links general circulation models (GCMs) with a stochastic weather generator and population dynamics models to predict species population responses to inter- and intra-annual temperature changes. This framework was utilized to explore future changes in populations of Bemisia tabaci, an invasive insect pest-species that affects multiple agricultural systems in the Mediterranean region. We considered three locations representing different pest status and climatic conditions: Montpellier (France), Seville (Spain), and Beit-Jamal (Israel). We produced ensembles of local daily temperature realizations representing current and future (mid-21st century) climatic conditions under two emission scenarios for the three locations. Our simulations predicted a significant increase in the average number of annual generations and in population size, and a significant lengthening of the growing season in all three locations. A negative effect was found only in Seville for the summer season, where future temperatures lead to a reduction in population size. High variability in population size was observed between years with similar annual mean temperatures, suggesting a strong effect of intra-annual temperature variation. Critical periods were from late spring to late summer in Montpellier and from late winter to early summer in Seville and Beit-Jamal. Although our analysis suggested that earlier seasonal activity does not necessarily lead to increased populations load unless an additional generation is produced, it is highly likely that the insect will become a significant pest of open-fields at Mediterranean latitudes above 40° during the next 50 years. Our simulations also implied that current predictions based on mean temperature anomalies are relatively conservative and it is better to apply stochastic tools to resolve complex responses to climate change while taking natural variability into account. In summary, we propose a modeling framework capable of determining distinct intra-annual temperature patterns leading to large or small population sizes, for pest risk assessment and management planning of both natural and agricultural ecosystems.

Frequency-dependent population dynamics: effect of sex ratio and mating system on the elasticity of population growth rate.

PubMed

Haridas, C V; Eager, Eric Alan; Rebarber, Richard; Tenhumberg, Brigitte

2014-11-01

When vital rates depend on population structure (e.g., relative frequencies of males or females), an important question is how the long-term population growth rate λ responds to changes in rates. For instance, availability of mates may depend on the sex ratio of the population and hence reproductive rates could be frequency-dependent. In such cases change in any vital rate alters the structure, which in turn, affect frequency-dependent rates. We show that the elasticity of λ to a rate is the sum of (i) the effect of the linear change in the rate and (ii) the effect of nonlinear changes in frequency-dependent rates. The first component is always positive and is the classical elasticity in density-independent models obtained directly from the population projection matrix. The second component can be positive or negative and is absent in density-independent models. We explicitly express each component of the elasticity as a function of vital rates, eigenvalues and eigenvectors of the population projection matrix. We apply this result to a two-sex model, where male and female fertilities depend on adult sex ratio α (ratio of females to males) and the mating system (e.g., polygyny) through a harmonic mating function. We show that the nonlinear component of elasticity to a survival rate is negligible only when the average number of mates (per male) is close to α. In a strictly monogamous species, elasticity to female survival is larger than elasticity to male survival when α<1 (less females). In a polygynous species, elasticity to female survival can be larger than that of male survival even when sex ratio is female biased. Our results show how demography and mating system together determine the response to selection on sex-specific vital rates. Copyright © 2014 Elsevier Inc. All rights reserved.

Genomic population structure of freshwater-resident and anadromous ide (Leuciscus idus) in north-western Europe.

PubMed

Skovrind, Mikkel; Olsen, Morten Tange; Vieira, Filipe Garrett; Pacheco, George; Carl, Henrik; Gilbert, M Thomas P; Møller, Peter Rask

2016-02-01

Climate change experts largely agree that future climate change and associated rises in oceanic water levels over the upcoming decades, will affect marine salinity levels. The subsequent effects on fish communities in estuarine ecosystems however, are less clear. One species that is likely to become increasingly affected by changes in salinity is the ide (Leuciscus idus). The ide is a stenohaline freshwater fish that primarily inhabits rivers, with frequent anadromous behavior when sea salinity does not exceed 15%. Unlike most other anadromous Baltic Sea fish species, the ide has yet to be subjected to large-scale stocking programs, and thus provides an excellent opportunity for studying the natural population structure across the current salinity gradient in the Danish Belts. To explore this, we used Genotyping-by-Sequencing to determine genomic population structure of both freshwater resident and anadromous ide populations in the western Baltic Sea region, and relate the results to the current salinity gradient and the demographic history of ide in the region. The sample sites separate into four clusters, with all anadromous populations in one cluster and the freshwater resident populations in the remaining three. Results demonstrate high level of differentiation between sites hosting freshwater resident populations, but little differentiation among anadromous populations. Thus ide exhibit the genomic population structure of both a typical freshwater species, and a typical anadromous species. In addition to providing a first insight into the population structure of north-western European ide, our data also (1) provide indications of a single illegal introduction by man; (2) suggest limited genetic effects of heavy pollution in the past; and (3) indicate possible historical anadromous behavior in a now isolated freshwater population.

Microsatellite DNA Analysis Revealed a Drastic Genetic Change of Plasmodium vivax Population in the Republic of Korea During 2002 and 2003

PubMed Central

Iwagami, Moritoshi; Hwang, Seung-Young; Kim, So-Hee; Park, So-Jung; Lee, Ga-Young; Matsumoto-Takahashi, Emilie Louise Akiko; Kho, Weon-Gyu; Kano, Shigeyuki

2013-01-01

Background Vivax malaria was successfully eliminated in the Republic of Korea (South Korea) in the late 1970s, but it was found to have re-emerged from 1993. In order to control malaria and evaluate the effectiveness of malaria controls, it is important to develop a spatiotemporal understanding of the genetic structure of the parasite population. Here, we estimated the population structure and temporal dynamics of the transmission of Plasmodium vivax in South Korea by analyzing microsatellite DNA markers of the parasite. Methodology/Principal Findings We analyzed 14 microsatellite DNA loci of the P. vivax genome from 163 South Korean isolates collected from 1994 to 2008. Allelic data were used to analyze linkage disequilibrium (LD), genetic differentiation and population structure, in order to make a detailed estimate of temporal change in the parasite population. The LD analysis showed a gradual decrease in LD levels, while the levels of genetic differentiation between successive years and analysis of the population structure based on the Bayesian approach suggested that a drastic genetic change occurred in the South Korean population during 2002 and 2003. Conclusions/Significance Although relapse and asymptomatic parasite carriage might influence the population structure to some extent, our results suggested the continual introduction of P. vivax into South Korea through other parasite population sources. One possible source, particularly during 2002 and 2003, is North Korea. Molecular epidemiology using microsatellite DNA of the P. vivax population is effective for assessing the population structure and temporal dynamics of parasite transmission; information that can assist in the elimination of vivax malaria in endemic areas. PMID:24205429

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

PubMed Central

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

2014-01-01

Habitat conversion for agriculture is a major driver of biodiversity loss, but our understanding of the demographic processes involved remains poor. We typically investigate the impacts of agriculture in isolation even though populations are likely to experience multiple, concurrent changes in the environment (e.g. land and climate change). Drivers of environmental change may interact to affect demography, but the mechanisms have yet to be explored fully in wild populations. Here, we investigate the mechanisms linking agricultural land use with breeding success using long-term data for the formerly Critically Endangered Mauritius kestrel Falco punctatus, a tropical forest specialist that also occupies agricultural habitats. We specifically focused on the relationship between breeding success, agriculture and the timing of breeding because the latter is sensitive to changes in climatic conditions (spring rainfall) and enables us to explore the interactive effects of different (land and climate) drivers of environmental change. Breeding success, measured as egg survival to fledging, declines seasonally in this population, but we found that the rate of this decline became increasingly rapid as the area of agriculture around a nest site increased. If the relationship between breeding success and agriculture was used in isolation to estimate the demographic impact of agriculture, it would significantly under-estimate breeding success in dry (early) springs and over-estimate breeding success in wet (late) springs. Analysis of prey delivered to nests suggests that the relationship between breeding success and agriculture might be due, in part, to spatial variation in the availability of native, arboreal geckos. Synthesis and applications. Agriculture modifies the seasonal decline in breeding success in this population. As springs are becoming wetter in our study area and since the kestrels breed later in wetter springs, the impact of agriculture on breeding success will become worse over time. Our results suggest that forest restoration designed to reduce the detrimental impacts of agriculture on breeding may also help reduce the detrimental effects of breeding late due to wetter springs. Our results therefore highlight the importance of considering the interactive effects of environmental change when managing wild populations. PMID:25558086

Predicting climate effects on Pacific sardine

PubMed Central

Deyle, Ethan R.; Fogarty, Michael; Hsieh, Chih-hao; Kaufman, Les; MacCall, Alec D.; Munch, Stephan B.; Perretti, Charles T.; Ye, Hao; Sugihara, George

2013-01-01

For many marine species and habitats, climate change and overfishing present a double threat. To manage marine resources effectively, it is necessary to adapt management to changes in the physical environment. Simple relationships between environmental conditions and fish abundance have long been used in both fisheries and fishery management. In many cases, however, physical, biological, and human variables feed back on each other. For these systems, associations between variables can change as the system evolves in time. This can obscure relationships between population dynamics and environmental variability, undermining our ability to forecast changes in populations tied to physical processes. Here we present a methodology for identifying physical forcing variables based on nonlinear forecasting and show how the method provides a predictive understanding of the influence of physical forcing on Pacific sardine. PMID:23536299

Conceptualizing the Influence of Social Agents of Behavior Change: A Meta-Analysis of the Effectiveness of HIV-Prevention Interventionists for Different Groups

PubMed Central

Durantini, Marta R.; Albarracín, Dolores; Mitchell, Amy L.; Earl, Allison N.; Gillette, Jeffrey C.

2016-01-01

A meta-analysis of 166 HIV-prevention interventions tested theoretical predictions about the effects of experts, lay community members, and similar and dissimilar others, as agents of change. In general, expert interventionists produced greater behavior change than lay community members, and the demographic and behavioral similarity between the interventionist and the recipients facilitated behavioral change. Equally importantly, there were differences across groups in the efficacy of various sources, especially among populations of low status and/or power. These findings support the hypothesis that unempowered populations are more sensitive to characteristics of the interventionists who can facilitate access to various resources. In addition, they suggest the need to ensure the availability of health professionals from diverse demographic and behavioral backgrounds. PMID:16536642

Climate change impacts on the conservation outlook of populations on the poleward periphery of species ranges: A case study of Canadian black-tailed prairie dogs (Cynomys ludovicianus).

PubMed

Stephens, Tara; Wilson, Sian C; Cassidy, Ffion; Bender, Darren; Gummer, David; Smith, Des H V; Lloyd, Natasha; McPherson, Jana M; Moehrenschlager, Axel

2018-02-01

Given climate change, species' climatically suitable habitats are increasingly expected to shift poleward. Some imperilled populations towards the poleward edge of their species' range might therefore conceivably benefit from climate change. Interactions between climate and population dynamics may be complex, however, with climate exerting effects both indirectly via influence over food availability and more directly, via effects on physiology and its implications for survival and reproduction. A thorough understanding of these interactions is critical for effective conservation management. We therefore examine the relationship between climate, survival and reproduction in Canadian black-tailed prairie dogs, a threatened keystone species in an imperilled ecosystem at the northern edge of the species' range. Our analyses considered 8 years of annual mark-recapture data (2007-2014) in relation to growing degree days, precipitation, drought status and winter severity, as well as year, sex, age and body mass. Survival was strongly influenced by the interaction of drought and body mass class, and winter temperature severity. Female reproductive status was associated with the interaction of growing degree days and growing season precipitation, with spring precipitation and with winter temperature severity. Results related to body mass suggested that climatic variables exerted their effects via regulation of food availability with potential linked effects of food quality, immunological and behavioural implications, and predation risk. Predictions of future increases in drought conditions in North America's grassland ecosystems have raised concerns for the outlook of Canadian black-tailed prairie dogs. Insights gained from the analyses, however, point to mitigating species management options targeted at decoupling the mechanisms by which climate exerts its negative influence. Our approach highlights the importance of understanding the interaction between climate and population dynamics in peripheral populations whose viability might ultimately determine their species' ability to track climatically suitable space. © 2017 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

Primary, secondary and tertiary effects of eco-climatic change: the medical response.

PubMed

Butler, Colin D; Harley, David

2010-04-01

Climatic and ecological change threaten human health globally. Manifestations include lost species, vanishing glaciers and more frequent heavy rain. In the second half of this century, accelerating sea level rise is likely to cause crop loss, and population dislocation. These problems may be magnified by dysfunctional human responses, including conflict. The population health consequences of these events can be classified as primary, secondary and tertiary. Primary signs include the acute and chronic stress of heat waves, and trauma from increased bush fires and flooding. Secondary signs are indirect, such as an altered distribution of arthropod vectors, intermediate hosts and pathogens that will produce changes in the epidemiology of many infectious diseases. More severe future health consequences of climate change are classified here as tertiary effects. If moderate or severe climate change scenarios prove accurate then these manifestations will occur over large areas, and could include famine, war and significant population displacement. Such effects would threaten governance and health. The health professions must respond to these challenges, especially the task of recognising and seeking to minimise tertiary health consequences. The gap between what we know and what we need to know concerning these issues can be narrowed by a new field of medical practice. The framework for this emerging discipline includes climate change, ecology and global health. Combined, these dimensions may be called ecomedicine. Actions to reduce individual emissions, to promote active transport (with its 'co-benefit' of preventing chronic disease), and involvement in group action to protect the environment and to prevent war, informed by understanding of the health of individual patients and populations, will be central to the practice of ecomedicine.

Climate Change, Wildland Fires and Public Health

NASA Astrophysics Data System (ADS)

Cascio, W. E.

2016-12-01

Climate change is contributing to an increase in the severity of wildland fires. The annual acreage burned in the U.S. has risen steadily since 1985, and the fire season has lengthened. Wildland fires impair air quality by producing massive quantities of particulate air pollutants and ozone precursors. Together particles and ozone exposures increase the risk of premature death and acute and chronic cardiovascular and respiratory morbidity among vulnerable individuals. Future wildfires are predicted to be larger, more severe and more frequent in some regions of the U.S and will contribute to an even greater proportion of the ambient air pollution, the disease burden and healthcare costs.While the projected magnitude of the public health impact of climate change-related wildfire events is uncertain, it is clear that the proportion of the U.S. population vulnerable to the adverse health effects of wildland fire and its smoke is increasing. An aging population with chronic respiratory diseases and increasing obesity and diabetes that heralds more cardiovascular disease will increase the vulnerability of the population to the adverse effects of wildfire smoke and associated stressors. Additionally, physiological changes attendant to aging decrease the capacity of aged-adults to tolerate wildfire smoke, heat, humidity, evacuation and recovery. Expansion of our cities into the wildland-urban interface is also placing a greater proportion of the population in closer proximity to wildland fire emissions with its associated health risks. The public health community has an opportunity to contribute to the broader national effort to mitigate climate change and wildland fire risk by working closely with the healthcare community to facilitate adaptive responses to climate change. Adaptation will increase the resilience of individuals and their communities and is anticipated to help mitigate the adverse health effects of wildland fire. This abstract does not reflect USEPA policy.

Harvesting wildlife affected by climate change: a modelling and management approach for polar bears.

PubMed

Regehr, Eric V; Wilson, Ryan R; Rode, Karyn D; Runge, Michael C; Stern, Harry L

2017-10-01

The conservation of many wildlife species requires understanding the demographic effects of climate change, including interactions between climate change and harvest, which can provide cultural, nutritional or economic value to humans.We present a demographic model that is based on the polar bear Ursus maritimus life cycle and includes density-dependent relationships linking vital rates to environmental carrying capacity ( K ). Using this model, we develop a state-dependent management framework to calculate a harvest level that (i) maintains a population above its maximum net productivity level (MNPL; the population size that produces the greatest net increment in abundance) relative to a changing K , and (ii) has a limited negative effect on population persistence.Our density-dependent relationships suggest that MNPL for polar bears occurs at approximately 0·69 (95% CI = 0·63-0·74) of K . Population growth rate at MNPL was approximately 0·82 (95% CI = 0·79-0·84) of the maximum intrinsic growth rate, suggesting relatively strong compensation for human-caused mortality.Our findings indicate that it is possible to minimize the demographic risks of harvest under climate change, including the risk that harvest will accelerate population declines driven by loss of the polar bear's sea-ice habitat. This requires that (i) the harvest rate - which could be 0 in some situations - accounts for a population's intrinsic growth rate, (ii) the harvest rate accounts for the quality of population data (e.g. lower harvest when uncertainty is large), and (iii) the harvest level is obtained by multiplying the harvest rate by an updated estimate of population size. Environmental variability, the sex and age of removed animals and risk tolerance can also affect the harvest rate. Synthesis and applications . We present a coupled modelling and management approach for wildlife that accounts for climate change and can be used to balance trade-offs among multiple conservation goals. In our example application to polar bears experiencing sea-ice loss, the goals are to maintain population viability while providing continued opportunities for subsistence harvest. Our approach may be relevant to other species for which near-term management is focused on human factors that directly influence population dynamics within the broader context of climate-induced habitat degradation.

Harvesting wildlife affected by climate change: a modelling and management approach for polar bears

USGS Publications Warehouse

Regehr, Eric V.; Wilson, Ryan R.; Rode, Karyn D.; Runge, Michael C.; Stern, Harry

2017-01-01

The conservation of many wildlife species requires understanding the demographic effects of climate change, including interactions between climate change and harvest, which can provide cultural, nutritional or economic value to humans.We present a demographic model that is based on the polar bear Ursus maritimus life cycle and includes density-dependent relationships linking vital rates to environmental carrying capacity (K). Using this model, we develop a state-dependent management framework to calculate a harvest level that (i) maintains a population above its maximum net productivity level (MNPL; the population size that produces the greatest net increment in abundance) relative to a changing K, and (ii) has a limited negative effect on population persistence.Our density-dependent relationships suggest that MNPL for polar bears occurs at approximately 0·69 (95% CI = 0·63–0·74) of K. Population growth rate at MNPL was approximately 0·82 (95% CI = 0·79–0·84) of the maximum intrinsic growth rate, suggesting relatively strong compensation for human-caused mortality.Our findings indicate that it is possible to minimize the demographic risks of harvest under climate change, including the risk that harvest will accelerate population declines driven by loss of the polar bear's sea-ice habitat. This requires that (i) the harvest rate – which could be 0 in some situations – accounts for a population's intrinsic growth rate, (ii) the harvest rate accounts for the quality of population data (e.g. lower harvest when uncertainty is large), and (iii) the harvest level is obtained by multiplying the harvest rate by an updated estimate of population size. Environmental variability, the sex and age of removed animals and risk tolerance can also affect the harvest rate.Synthesis and applications. We present a coupled modelling and management approach for wildlife that accounts for climate change and can be used to balance trade-offs among multiple conservation goals. In our example application to polar bears experiencing sea-ice loss, the goals are to maintain population viability while providing continued opportunities for subsistence harvest. Our approach may be relevant to other species for which near-term management is focused on human factors that directly influence population dynamics within the broader context of climate-induced habitat degradation.

[The effective growth of the population as a factor of regional social and economic activity and living conditions].

PubMed

Rakowski, W

1993-01-01

"The author analyses changes in location of the Polish population in the years 1989-1991. From the analysis it appears...that the role of the Warszawa, Lodz, Wroclaw, Krakow and Legnica voivodeships in the process of population concentration is decreasing, and...the role of Western, Northern and South-Eastern regions [is increasing].... It is difficult to say how much [current changes are] due to economic transformations and how much to the crisis in local economies." (SUMMARY IN ENG AND RUS) excerpt

Biodiversity Areas under Threat: Overlap of Climate Change and Population Pressures on the World's Biodiversity Priorities.

PubMed

Aukema, Juliann E; Pricope, Narcisa G; Husak, Gregory J; Lopez-Carr, David

2017-01-01

Humans and the ecosystem services they depend on are threatened by climate change. Places with high or growing human population as well as increasing climate variability, have a reduced ability to provide ecosystem services just as the need for these services is most critical. A spiral of vulnerability and ecosystem degradation often ensues in such places. We apply different global conservation schemes as proxies to examine the spatial relation between wet season precipitation, population change over three decades, and natural resource conservation. We pose two research questions: 1) Where are biodiversity and ecosystem services vulnerable to the combined effects of climate change and population growth? 2) Where are human populations vulnerable to degraded ecosystem services? Results suggest that globally only about 20% of the area between 50 degrees latitude North and South has experienced significant change-largely wetting-in wet season precipitation. Approximately 40% of rangelands and 30% of rainfed agriculture lands have experienced significant precipitation changes, with important implications for food security. Over recent decades a number of critical conservation areas experienced high population growth concurrent with significant wetting or drying (e.g. the Horn of Africa, Himalaya, Western Ghats, and Sri Lanka), posing challenges not only for human adaptation but also to the protection and sustenance of biodiversity and ecosystem services. Identifying areas of climate and population risk and their overlap with conservation priorities can help to target activities and resources that promote biodiversity and ecosystem services while improving human well-being.

Glucocorticoid stress hormones and the effect of predation risk on elk reproduction.

PubMed

Creel, Scott; Winnie, John A; Christianson, David

2009-07-28

Predators affect prey demography through direct predation and through the costs of antipredator behavioral responses, or risk effects. Experiments have shown that risk effects can comprise a substantial proportion of a predator's total effect on prey dynamics, but we know little about their strength in wild populations, or the physiological mechanisms that mediate them. When wolves are present, elk alter their grouping patterns, vigilance, foraging behavior, habitat selection, and diet. These responses are associated with decreased progesterone levels, decreased calf production, and reduced population size [Creel S, Christianson D, Liley S, Winnie JA (2007) Science 315:960]. Two general mechanisms for the effect of predation risk on reproduction have been proposed: the predation stress hypothesis and the predator-sensitive-food hypothesis. Here, we used enzyme immunoassay to measure fecal glucocorticoid metabolite concentrations for 1,205 samples collected from 4 elk populations over 4 winters to test the hypothesis that the effect of predation risk on elk reproduction is mediated by chronic stress. Across populations and years, fecal glucocorticoid concentrations were not related to predator-prey ratios, progesterone concentrations or calf-cow ratios. Overall, the effect of wolf presence on elk reproduction is better explained by changes in foraging patterns that carry nutritional costs than by changes in glucocorticoid concentrations.

Glucocorticoid stress hormones and the effect of predation risk on elk reproduction

PubMed Central

Creel, Scott; Winnie, John A.; Christianson, David

2009-01-01

Predators affect prey demography through direct predation and through the costs of antipredator behavioral responses, or risk effects. Experiments have shown that risk effects can comprise a substantial proportion of a predator's total effect on prey dynamics, but we know little about their strength in wild populations, or the physiological mechanisms that mediate them. When wolves are present, elk alter their grouping patterns, vigilance, foraging behavior, habitat selection, and diet. These responses are associated with decreased progesterone levels, decreased calf production, and reduced population size [Creel S, Christianson D, Liley S, Winnie JA (2007) Science 315:960]. Two general mechanisms for the effect of predation risk on reproduction have been proposed: the predation stress hypothesis and the predator-sensitive-food hypothesis. Here, we used enzyme immunoassay to measure fecal glucocorticoid metabolite concentrations for 1,205 samples collected from 4 elk populations over 4 winters to test the hypothesis that the effect of predation risk on elk reproduction is mediated by chronic stress. Across populations and years, fecal glucocorticoid concentrations were not related to predator-prey ratios, progesterone concentrations or calf-cow ratios. Overall, the effect of wolf presence on elk reproduction is better explained by changes in foraging patterns that carry nutritional costs than by changes in glucocorticoid concentrations. PMID:19617549

Skeletal and dental effects of rapid maxillary expansion assessed through three-dimensional imaging: A multicenter study.

PubMed

Luebbert, Joshua; Ghoneima, Ahmed; Lagravère, Manuel O

2016-03-01

The aim of this study was to determine the skeletal and dental changes in rapid maxillary expansion treatments in two different populations assessed through cone-beam computer tomography (CBCT). Twenty-one patients from Edmonton, Canada and 16 patients from Cairo, Egypt with maxillary transverse deficiency (11-17 years old) were treated with a tooth-borne maxillary expander (Hyrax). CBCTs were obtained from each patient at two time points (initial T1 and at removal of appliance at 3-6 months T2). CBCTs were analyzed using AVIZO software and landmarks were placed on skeletal and dental anatomical structures on the cranial base, maxilla and mandible. Descriptive statistics, intraclass correlation coefficients and one-way ANOVA analysis were used to determine if there were skeletal and dental changes and if these changes were statistically different between both populations. Descriptive statistics show that dental changes were larger than skeletal changes for both populations. Skeletal and dental changes between populations were not statistically different (P<0.05) from each other with the exception of the upper incisor proclination being larger in the Indiana group (P>0.05). Rapid maxillary expansion treatments in different populations demonstrate similar skeletal and dental changes. These changes are greater on the dental structures compared to the skeletal ones in a 4:1 ratio. Copyright © 2015 CEO. Published by Elsevier Masson SAS. All rights reserved.

Are whooping cranes destined for extinction? Climate change imperils recruitment and population growth.

PubMed

Butler, Matthew J; Metzger, Kristine L; Harris, Grant M

2017-04-01

Identifying climatic drivers of an animal population's vital rates and locating where they operate steers conservation efforts to optimize species recovery. The population growth of endangered whooping cranes ( Grus americana ) hinges on juvenile recruitment. Therefore, we identify climatic drivers (solar activity [sunspots] and weather) of whooping crane recruitment throughout the species' life cycle (breeding, migration, wintering). Our method uses a repeated cross-validated absolute shrinkage and selection operator approach to identify drivers of recruitment. We model effects of climate change on those drivers to predict whooping crane population growth given alternative scenarios of climate change and solar activity. Years with fewer sunspots indicated greater recruitment. Increased precipitation during autumn migration signified less recruitment. On the breeding grounds, fewer days below freezing during winter and more precipitation during breeding suggested less recruitment. We predicted whooping crane recruitment and population growth may fall below long-term averages during all solar cycles when atmospheric CO 2 concentration increases, as expected, to 500 ppm by 2050. Species recovery during a typical solar cycle with 500 ppm may require eight times longer than conditions without climate change and the chance of population decline increases to 31%. Although this whooping crane population is growing and may appear secure, long-term threats imposed by climate change and increased solar activity may jeopardize its persistence. Weather on the breeding grounds likely affects recruitment through hydrological processes and predation risk, whereas precipitation during autumn migration may influence juvenile mortality. Mitigating threats or abating climate change should occur within ≈30 years or this wild population of whooping cranes may begin declining.

Comparative Assessment of the Effects of Climate Change on Heat- and Cold-Related Mortality in the United Kingdom and Australia

PubMed Central

Dear, Keith; Hajat, Shakoor; Heaviside, Clare; Eggen, Bernd; McMichael, Anthony J.

2014-01-01

Background: High and low ambient temperatures are associated with increased mortality in temperate and subtropical climates. Temperature-related mortality patterns are expected to change throughout this century because of climate change. Objectives: We compared mortality associated with heat and cold in UK regions and Australian cities for current and projected climates and populations. Methods: Time-series regression analyses were carried out on daily mortality in relation to ambient temperatures for UK regions and Australian cities to estimate relative risk functions for heat and cold and variations in risk parameters by age. Excess deaths due to heat and cold were estimated for future climates. Results: In UK regions, cold-related mortality currently accounts for more than one order of magnitude more deaths than heat-related mortality (around 61 and 3 deaths per 100,000 population per year, respectively). In Australian cities, approximately 33 and 2 deaths per 100,000 population are associated every year with cold and heat, respectively. Although cold-related mortality is projected to decrease due to climate change to approximately 42 and 19 deaths per 100,000 population per year in UK regions and Australian cities, heat-related mortality is projected to increase to around 9 and 8 deaths per 100,000 population per year, respectively, by the 2080s, assuming no changes in susceptibility and structure of the population. Conclusions: Projected changes in climate are likely to lead to an increase in heat-related mortality in the United Kingdom and Australia over this century, but also to a decrease in cold-related deaths. Future temperature-related mortality will be amplified by aging populations. Health protection from hot weather will become increasingly necessary in both countries, while protection from cold weather will be still needed. Citation: Vardoulakis S, Dear K, Hajat S, Heaviside C, Eggen B, McMichael AJ. 2014. Comparative assessment of the effects of climate change on heat- and cold-related mortality in the United Kingdom and Australia. Environ Health Perspect 122:1285–1292; http://dx.doi.org/10.1289/ehp.1307524 PMID:25222967

Bird response to future climate and forest management focused on mitigating climate change

Treesearch

Jaymi J. LeBrun; Jeffrey E. Schneiderman; Frank R. Thompson; William D. Dijak; Jacob S. Fraser; Hong S. He; Joshua J. Millspaugh

2016-01-01

Context. Global temperatures are projected to increase and affect forests and wildlife populations. Forest management can potentially mitigate climateinduced changes through promoting carbon sequestration, forest resilience, and facilitated change. Objectives. We modeled direct and indirect effects of climate change on avian...

Nurse Scheduling by Cooperative GA with Effective Mutation Operator

NASA Astrophysics Data System (ADS)

Ohki, Makoto

In this paper, we propose an effective mutation operators for Cooperative Genetic Algorithm (CGA) to be applied to a practical Nurse Scheduling Problem (NSP). The nurse scheduling is a very difficult task, because NSP is a complex combinatorial optimizing problem for which many requirements must be considered. In real hospitals, the schedule changes frequently. The changes of the shift schedule yields various problems, for example, a fall in the nursing level. We describe a technique of the reoptimization of the nurse schedule in response to a change. The conventional CGA is superior in ability for local search by means of its crossover operator, but often stagnates at the unfavorable situation because it is inferior to ability for global search. When the optimization stagnates for long generation cycle, a searching point, population in this case, would be caught in a wide local minimum area. To escape such local minimum area, small change in a population should be required. Based on such consideration, we propose a mutation operator activated depending on the optimization speed. When the optimization stagnates, in other words, when the optimization speed decreases, the mutation yields small changes in the population. Then the population is able to escape from a local minimum area by means of the mutation. However, this mutation operator requires two well-defined parameters. This means that user have to consider the value of these parameters carefully. To solve this problem, we propose a periodic mutation operator which has only one parameter to define itself. This simplified mutation operator is effective over a wide range of the parameter value.

A hierarchical model for estimating change in American Woodcock populations

USGS Publications Warehouse

Sauer, J.R.; Link, W.A.; Kendall, W.L.; Kelley, J.R.; Niven, D.K.

2008-01-01

The Singing-Ground Survey (SGS) is a primary source of information on population change for American woodcock (Scolopax minor). We analyzed the SGS using a hierarchical log-linear model and compared the estimates of change and annual indices of abundance to a route regression analysis of SGS data. We also grouped SGS routes into Bird Conservation Regions (BCRs) and estimated population change and annual indices using BCRs within states and provinces as strata. Based on the hierarchical model?based estimates, we concluded that woodcock populations were declining in North America between 1968 and 2006 (trend = -0.9%/yr, 95% credible interval: -1.2, -0.5). Singing-Ground Survey results are generally similar between analytical approaches, but the hierarchical model has several important advantages over the route regression. Hierarchical models better accommodate changes in survey efficiency over time and space by treating strata, years, and observers as random effects in the context of a log-linear model, providing trend estimates that are derived directly from the annual indices. We also conducted a hierarchical model analysis of woodcock data from the Christmas Bird Count and the North American Breeding Bird Survey. All surveys showed general consistency in patterns of population change, but the SGS had the shortest credible intervals. We suggest that population management and conservation planning for woodcock involving interpretation of the SGS use estimates provided by the hierarchical model.

POPULATION DYNAMICS OF SMALL MAMMALS ACROSS A NITROGEN AMENDED LANDSCAPE

EPA Science Inventory

Biogeochemical alterations of the nitrogen cycle from anthropogenic activities could have significant effects on ecological processes at the population, community and ecosystem levels. Nitrogen additions in grasslands have produced qualitative and quantitative changes in vegetat...

Population trends from the North American Breeding Bird Survey

USGS Publications Warehouse

Peterjohn, B.G.; Sauer, J.R.; Robbins, C.S.; Martin, Thomas E.; Finch, Deborah M.

1995-01-01

INTRODUCTION: Most Neotropical migrant birds are difficult to count accurately and are moderately common over large breeding distributions. Consequently, little historical information exists on their large-scale population changes, and most of this information is anecdotal. Surveys begun in this century such as Breeding Bird Censuses and Christmas Bird Counts have the potential to provide this information, but only the North American Breeding Bird Survey (BBS) achieves the extensive continental coverage necessary to document population changes for most Neotropical migrant birds. Conservationists and ecologists have begun to use BBS data to estimate population trends, but there is still widespread confusion over exactly what these data show regarding population changes. In this chapter, we review the current state of knowledge regarding population changes in Neotropical migrant birds and the methods used to analyze these changes. The primary emphasis is on the BBS (Robbins et al. 1986) because this survey provides the best available data for estimating trends of Neotropical migrants on a continental scale. To address questions about methods of analyzing survey data, we review and compare some alternative methods of analyzing BBS data. We also discuss the effectiveness of the BBS in sampling Neotropical migrant species, and review possibilities for use of alternative data sets to verify trends from the BBS.

Climate variability, rice production and groundwater depletion in India

NASA Astrophysics Data System (ADS)

Bhargava, Alok

2018-03-01

This paper modeled the proximate determinants of rice outputs and groundwater depths in 27 Indian states during 1980-2010. Dynamic random effects models were estimated by maximum likelihood at state and well levels. The main findings from models for rice outputs were that temperatures and rainfall levels were significant predictors, and the relationships were quadratic with respect to rainfall. Moreover, nonlinearities with respect to population changes indicated greater rice production with population increases. Second, groundwater depths were positively associated with temperatures and negatively with rainfall levels and there were nonlinear effects of population changes. Third, dynamic models for in situ groundwater depths in 11 795 wells in mainly unconfined aquifers, accounting for latitudes, longitudes and altitudes, showed steady depletion. Overall, the results indicated that population pressures on food production and environment need to be tackled via long-term healthcare, agricultural, and groundwater recharge policies in India.

Global change and terrestrial plant community dynamics

DOE PAGES

Franklin, Janet; Serra-Diaz, Josep M.; Syphard, Alexandra D.; ...

2016-02-29

Anthropogenic drivers of global change include rising atmospheric concentrations of carbon dioxide and other greenhouse gasses and resulting changes in the climate, as well as nitrogen deposition, biotic invasions, altered disturbance regimes, and land-use change. Predicting the effects of global change on terrestrial plant communities is crucial because of the ecosystem services vegetation provides, from climate regulation to forest products. In this article, we present a framework for detecting vegetation changes and attributing them to global change drivers that incorporates multiple lines of evidence from spatially extensive monitoring networks, distributed experiments, remotely sensed data, and historical records. Based on amore » literature review, we summarize observed changes and then describe modeling tools that can forecast the impacts of multiple drivers on plant communities in an era of rapid change. Observed responses to changes in temperature, water, nutrients, land use, and disturbance show strong sensitivity of ecosystem productivity and plant population dynamics to water balance and long-lasting effects of disturbance on plant community dynamics. Persistent effects of land-use change and human-altered fire regimes on vegetation can overshadow or interact with climate change impacts. Models forecasting plant community responses to global change incorporate shifting ecological niches, population dynamics, species interactions, spatially explicit disturbance, ecosystem processes, and plant functional responses. Lastly, monitoring, experiments, and models evaluating multiple change drivers are needed to detect and predict vegetation changes in response to 21st century global change.« less

Global change and terrestrial plant community dynamics

PubMed Central

Franklin, Janet; Serra-Diaz, Josep M.; Syphard, Alexandra D.; Regan, Helen M.

2016-01-01

Anthropogenic drivers of global change include rising atmospheric concentrations of carbon dioxide and other greenhouse gasses and resulting changes in the climate, as well as nitrogen deposition, biotic invasions, altered disturbance regimes, and land-use change. Predicting the effects of global change on terrestrial plant communities is crucial because of the ecosystem services vegetation provides, from climate regulation to forest products. In this paper, we present a framework for detecting vegetation changes and attributing them to global change drivers that incorporates multiple lines of evidence from spatially extensive monitoring networks, distributed experiments, remotely sensed data, and historical records. Based on a literature review, we summarize observed changes and then describe modeling tools that can forecast the impacts of multiple drivers on plant communities in an era of rapid change. Observed responses to changes in temperature, water, nutrients, land use, and disturbance show strong sensitivity of ecosystem productivity and plant population dynamics to water balance and long-lasting effects of disturbance on plant community dynamics. Persistent effects of land-use change and human-altered fire regimes on vegetation can overshadow or interact with climate change impacts. Models forecasting plant community responses to global change incorporate shifting ecological niches, population dynamics, species interactions, spatially explicit disturbance, ecosystem processes, and plant functional responses. Monitoring, experiments, and models evaluating multiple change drivers are needed to detect and predict vegetation changes in response to 21st century global change. PMID:26929338

Selective toxin effects on faster and slower growing individuals in the formation of hormesis at the population level - A case study with Lactuca sativa and PCIB.

PubMed

Belz, Regina G; Sinkkonen, Aki

2016-10-01

Natural plant populations have large phenotypic plasticity that enhances acclimation to local stress factors such as toxin exposures. While consequences of high toxin exposures are well addressed, effects of low-dose toxin exposures on plant populations are seldom investigated. In particular, the importance of 'selective low-dose toxicity' and hormesis, i.e. stimulatory effects, has not been studied simultaneously. Since selective toxicity can change the size distribution of populations, we assumed that hormesis alters the size distribution at the population level, and investigated whether and how these two low-dose phenomena coexist. The study was conducted with Lactuca sativa L. exposed to the auxin-inhibitor 2-(p-chlorophenoxy)-2-methylpropionic acid (PCIB) in vitro. In two separate experiments, L. sativa was exposed to 12 PCIB doses in 24 replicates (50 plants/replicate). Shoot/root growth responses at the population level were compared to the fast-growing (≥90% percentile) and the slow-growing subpopulations (≤10% percentile) by Mann-Whitney U testing and dose-response modelling. In the formation of pronounced PCIB hormesis at the population level, low-dose effects proved selective, but widely stimulatory which seems to counteract low-dose selective toxicity. The selectivity of hormesis was dose- and growth rate-dependent. Stimulation occurred at lower concentrations and stimulation percentage was higher among slow-growing individuals, but partly or entirely masked at the population level by moderate or negligible stimulation among the faster growing individuals. We conclude that the hormetic effect up to the maximum stimulation may be primarily facilitated by an increase in size of the most slow-growing individuals, while thereafter it seems that mainly the fast-growing individuals contributed to the observed hormesis at the population level. As size distribution within a population is related to survival, our study hints that selective effects on slow- and fast-growing individuals may change population dynamics, providing that similar effects can be repeated under field conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

Ecological feedbacks can reduce population-level efficacy of wildlife fertility control

USGS Publications Warehouse

Ransom, Jason I.; Powers, Jenny G.; Hobbs, N. Thompson; Baker, Dan L.

2014-01-01

1. Anthropogenic stress on natural systems, particularly the fragmentation of landscapes and the extirpation of predators from food webs, has intensified the need to regulate abundance of wildlife populations with management. Controlling population growth using fertility control has been considered for almost four decades, but nearly all research has focused on understanding effects of fertility control agents on individual animals. Questions about the efficacy of fertility control as a way to control populations remain largely unanswered. 2. Collateral consequences of contraception can produce unexpected changes in birth rates, survival, immigration and emigration that may reduce the effectiveness of regulating animal abundance. The magnitude and frequency of such effects vary with species-specific social and reproductive systems, as well as connectivity of populations. Developing models that incorporate static demographic parameters from populations not controlled by contraception may bias predictions of fertility control efficacy. 3. Many population-level studies demonstrate that changes in survival and immigration induced by fertility control can compensate for the reduction in births caused by contraception. The most successful cases of regulating populations using fertility control come from applications of contraceptives to small, closed populations of gregarious and easily accessed species. 4. Fertility control can result in artificial selection pressures on the population and may lead to long-term unintentional genetic consequences. The magnitude of such selection is dependent on individual heritability and behavioural traits, as well as environmental variation. 5. Synthesis and applications. Understanding species' life-history strategies, biology, behavioural ecology and ecological context is critical to developing realistic expectations of regulating populations using fertility control. Before time, effort and funding are invested in wildlife contraception, managers may need to consider the possibility that many species and populations can compensate for reduction in fecundity, and this could minimize any reduction in population growth rate.

Ecological feedbacks can reduce population-level efficacy of wildlife fertility control

PubMed Central

Ransom, Jason I; Powers, Jenny G; Thompson Hobbs, N; Baker, Dan L

2014-01-01

Anthropogenic stress on natural systems, particularly the fragmentation of landscapes and the extirpation of predators from food webs, has intensified the need to regulate abundance of wildlife populations with management. Controlling population growth using fertility control has been considered for almost four decades, but nearly all research has focused on understanding effects of fertility control agents on individual animals. Questions about the efficacy of fertility control as a way to control populations remain largely unanswered. Collateral consequences of contraception can produce unexpected changes in birth rates, survival, immigration and emigration that may reduce the effectiveness of regulating animal abundance. The magnitude and frequency of such effects vary with species-specific social and reproductive systems, as well as connectivity of populations. Developing models that incorporate static demographic parameters from populations not controlled by contraception may bias predictions of fertility control efficacy. Many population-level studies demonstrate that changes in survival and immigration induced by fertility control can compensate for the reduction in births caused by contraception. The most successful cases of regulating populations using fertility control come from applications of contraceptives to small, closed populations of gregarious and easily accessed species. Fertility control can result in artificial selection pressures on the population and may lead to long-term unintentional genetic consequences. The magnitude of such selection is dependent on individual heritability and behavioural traits, as well as environmental variation. Synthesis and applications. Understanding species' life-history strategies, biology, behavioural ecology and ecological context is critical to developing realistic expectations of regulating populations using fertility control. Before time, effort and funding are invested in wildlife contraception, managers may need to consider the possibility that many species and populations can compensate for reduction in fecundity, and this could minimize any reduction in population growth rate. PMID:25558083

Why sampling scheme matters: the effect of sampling scheme on landscape genetic results

Treesearch

Michael K. Schwartz; Kevin S. McKelvey

2008-01-01

There has been a recent trend in genetic studies of wild populations where researchers have changed their sampling schemes from sampling pre-defined populations to sampling individuals uniformly across landscapes. This reflects the fact that many species under study are continuously distributed rather than clumped into obvious "populations". Once individual...

sGD software for estimating spatially explicit indices of genetic diversity

Treesearch

A. J. Shirk; Samuel Cushman

2011-01-01

Anthropogenic landscape changes have greatly reduced the population size, range and migration rates of many terrestrial species. The small local effective population size of remnant populations favours loss of genetic diversity leading to reduced fitness and adaptive potential, and thus ultimately greater extinction risk. Accurately quantifying genetic diversity is...

rSPACE: Spatially based power analysis for conservation and ecology

Treesearch

Martha M. Ellis; Jacob S. Ivan; Jody M. Tucker; Michael K. Schwartz

2015-01-01

1.) Power analysis is an important step in designing effective monitoring programs to detect trends in plant or animal populations. Although project goals often focus on detecting changes in population abundance, logistical constraints may require data collection on population indices, such as detection/non-detection data for occupancy estimation. 2.) We describe the...

Weighing the relative potential impacts of climate change and land-use change on an endangered bird.

PubMed

Bancroft, Betsy A; Lawler, Joshua J; Schumaker, Nathan H

2016-07-01

Climate change and land-use change are projected to be the two greatest drivers of biodiversity loss over the coming century. Land-use change has resulted in extensive habitat loss for many species. Likewise, climate change has affected many species resulting in range shifts, changes in phenology, and altered interactions. We used a spatially explicit, individual-based model to explore the effects of land-use change and climate change on a population of the endangered Red-cockaded Woodpecker (RCW; Picoides borealis). We modeled the effects of land-use change using multiple scenarios representing different spatial arrangements of new training areas for troops across Fort Benning. We used projected climate-driven changes in habitat and changes in reproductive output to explore the potential effects of climate change. We summarized potential changes in habitat based on the output of the dynamic vegetation model LPJ-GUESS, run for multiple climate change scenarios through the year 2100. We projected potential changes in reproduction based on an empirical relationship between spring precipitation and the mean number of successful fledglings produced per nest attempt. As modeled in our study, climate change had virtually no effect on the RCW population. Conversely, simulated effects of land-use change resulted in the loss of up to 28 breeding pairs by 2100. However, the simulated impacts of development depended on where the development occurred and could be completely avoided if the new training areas were placed in poor-quality habitat. Our results demonstrate the flexibility inherent in many systems that allows seemingly incompatible human land uses, such as development, and conservation actions to exist side by side.

Graptolite community responses to global climate change and the Late Ordovician mass extinction.

PubMed

Sheets, H David; Mitchell, Charles E; Melchin, Michael J; Loxton, Jason; Štorch, Petr; Carlucci, Kristi L; Hawkins, Andrew D

2016-07-26

Mass extinctions disrupt ecological communities. Although climate changes produce stress in ecological communities, few paleobiological studies have systematically addressed the impact of global climate changes on the fine details of community structure with a view to understanding how changes in community structure presage, or even cause, biodiversity decline during mass extinctions. Based on a novel Bayesian approach to biotope assessment, we present a study of changes in species abundance distribution patterns of macroplanktonic graptolite faunas (∼447-444 Ma) leading into the Late Ordovician mass extinction. Communities at two contrasting sites exhibit significant decreases in complexity and evenness as a consequence of the preferential decline in abundance of dysaerobic zone specialist species. The observed changes in community complexity and evenness commenced well before the dramatic population depletions that mark the tipping point of the extinction event. Initially, community changes tracked changes in the oceanic water masses, but these relations broke down during the onset of mass extinction. Environmental isotope and biomarker data suggest that sea surface temperature and nutrient cycling in the paleotropical oceans changed sharply during the latest Katian time, with consequent changes in the extent of the oxygen minimum zone and phytoplankton community composition. Although many impacted species persisted in ephemeral populations, increased extinction risk selectively depleted the diversity of paleotropical graptolite species during the latest Katian and early Hirnantian. The effects of long-term climate change on habitats can thus degrade populations in ways that cascade through communities, with effects that culminate in mass extinction.

Graptolite community responses to global climate change and the Late Ordovician mass extinction

NASA Astrophysics Data System (ADS)

Sheets, H. David; Mitchell, Charles E.; Melchin, Michael J.; Loxton, Jason; Štorch, Petr; Carlucci, Kristi L.; Hawkins, Andrew D.

2016-07-01

Mass extinctions disrupt ecological communities. Although climate changes produce stress in ecological communities, few paleobiological studies have systematically addressed the impact of global climate changes on the fine details of community structure with a view to understanding how changes in community structure presage, or even cause, biodiversity decline during mass extinctions. Based on a novel Bayesian approach to biotope assessment, we present a study of changes in species abundance distribution patterns of macroplanktonic graptolite faunas (˜447-444 Ma) leading into the Late Ordovician mass extinction. Communities at two contrasting sites exhibit significant decreases in complexity and evenness as a consequence of the preferential decline in abundance of dysaerobic zone specialist species. The observed changes in community complexity and evenness commenced well before the dramatic population depletions that mark the tipping point of the extinction event. Initially, community changes tracked changes in the oceanic water masses, but these relations broke down during the onset of mass extinction. Environmental isotope and biomarker data suggest that sea surface temperature and nutrient cycling in the paleotropical oceans changed sharply during the latest Katian time, with consequent changes in the extent of the oxygen minimum zone and phytoplankton community composition. Although many impacted species persisted in ephemeral populations, increased extinction risk selectively depleted the diversity of paleotropical graptolite species during the latest Katian and early Hirnantian. The effects of long-term climate change on habitats can thus degrade populations in ways that cascade through communities, with effects that culminate in mass extinction.

A theoretical quantitative genetic study of negative ecological interactions and extinction times in changing environments.

PubMed

Jones, Adam G

2008-04-25

Rapid human-induced changes in the environment at local, regional and global scales appear to be contributing to population declines and extinctions, resulting in an unprecedented biodiversity crisis. Although in the short term populations can respond ecologically to environmental alterations, in the face of persistent change populations must evolve or become extinct. Existing models of evolution and extinction in changing environments focus only on single species, even though the dynamics of extinction almost certainly depend upon the nature of species interactions. Here, I use a model of quantitative trait evolution in a two-species community to show that negative ecological interactions, such as predation and competition, can produce unexpected results regarding time to extinction. Under some circumstances, negative interactions can be expected to hasten the extinction of species declining in numbers. However, under other circumstances, negative interactions can actually increase times to extinction. This effect occurs across a wide range of parameter values and can be substantial, in some cases allowing a population to persist for 40 percent longer than it would in the absence of the species interaction. This theoretical study indicates that negative species interactions can have unexpected positive effects on times to extinction. Consequently, detailed studies of selection and demographics will be necessary to predict the consequences of species interactions in changing environments for any particular ecological community.

Climate change and health: Why should India be concerned?

PubMed

Majra, J P; Gur, A

2009-04-01

Overwhelming evidence shows that climate change presents growing threats to public health security - from extreme weather-related disasters to wider spread of such vector-borne diseases as malaria and dengue. The impacts of climate on human health will not be evenly distributed around the world. The Third Assessment Report (Intergovernmental Panel on Climate Change-2001) concluded that vulnerability to climate change is a function of exposure, sensitivity, and adaptive capacity. Developing country populations, particularly in small island states, arid and high mountain zones, and in densely populated coastal areas are considered to be particularly vulnerable. India is a large developing country, with the Great Himalayas, the world's third largest ice mass in the north, 7500 km long, and densely populated coast line in the south. Nearly 700 million of her over one billion population living in rural areas directly depends on climate-sensitive sectors (agriculture, forests, and fisheries) and natural resources (such as water, biodiversity, mangroves, coastal zones, grasslands) for their subsistence and livelihoods. Heat wave, floods (land and coastal), and draughts occur commonly. Malaria, malnutrition, and diarrhea are major public health problems. Any further increase, as projected in weather-related disasters and related health effects, may cripple the already inadequate public health infrastructure in the country. Hence, there is an urgent need to respond to the situation. Response options to protect health from effects of climate change include mitigation as well as adaptation. Both can complement each other and together can significantly reduce the risks of climate change.

Regional Distribution Shifts Help Explain Local Changes in Wintering Raptor Abundance: Implications for Interpreting Population Trends

PubMed Central

Paprocki, Neil; Heath, Julie A.; Novak, Stephen J.

2014-01-01

Studies of multiple taxa across broad-scales suggest that species distributions are shifting poleward in response to global climate change. Recognizing the influence of distribution shifts on population indices will be an important part of interpreting trends within management units because current practice often assumes that changes in local populations reflect local habitat conditions. However, the individual- and population-level processes that drive distribution shifts may occur across a large, regional scale and have little to do with the habitats within the management unit. We examined the latitudinal center of abundance for the winter distributions of six western North America raptor species using Christmas Bird Counts from 1975–2011. Also, we considered whether population indices within western North America Bird Conservation Regions (BCRs) were explained by distribution shifts. All six raptors had significant poleward shifts in their wintering distributions over time. Rough-legged Hawks (Buteo lagopus) and Golden Eagles (Aquila chrysaetos) showed the fastest rate of change, with 8.41 km yr−1 and 7.74 km yr−1 shifts, respectively. Raptors may be particularly responsive to warming winters because of variable migration tendencies, intraspecific competition for nesting sites that drives males to winter farther north, or both. Overall, 40% of BCR population trend models were improved by incorporating information about wintering distributions; however, support for the effect of distribution on BCR indices varied by species with Rough-legged Hawks showing the most evidence. These results emphasize the importance of understanding how regional distribution shifts influence local-scale population indices. If global climate change is altering distribution patterns, then trends within some management units may not reflect changes in local habitat conditions. The methods used to monitor and manage bird populations within local BCRs will fundamentally change as species experience changes in distribution in response to climate change. PMID:24466253

DOE Office of Scientific and Technical Information (OSTI.GOV)

Franklin, Janet; Serra-Diaz, Josep M.; Syphard, Alexandra D.

Anthropogenic drivers of global change include rising atmospheric concentrations of carbon dioxide and other greenhouse gasses and resulting changes in the climate, as well as nitrogen deposition, biotic invasions, altered disturbance regimes, and land-use change. Predicting the effects of global change on terrestrial plant communities is crucial because of the ecosystem services vegetation provides, from climate regulation to forest products. In this article, we present a framework for detecting vegetation changes and attributing them to global change drivers that incorporates multiple lines of evidence from spatially extensive monitoring networks, distributed experiments, remotely sensed data, and historical records. Based on amore » literature review, we summarize observed changes and then describe modeling tools that can forecast the impacts of multiple drivers on plant communities in an era of rapid change. Observed responses to changes in temperature, water, nutrients, land use, and disturbance show strong sensitivity of ecosystem productivity and plant population dynamics to water balance and long-lasting effects of disturbance on plant community dynamics. Persistent effects of land-use change and human-altered fire regimes on vegetation can overshadow or interact with climate change impacts. Models forecasting plant community responses to global change incorporate shifting ecological niches, population dynamics, species interactions, spatially explicit disturbance, ecosystem processes, and plant functional responses. Lastly, monitoring, experiments, and models evaluating multiple change drivers are needed to detect and predict vegetation changes in response to 21st century global change.« less

Natural disasters and population mobility in Bangladesh.

PubMed

Gray, Clark L; Mueller, Valerie

2012-04-17

The consequences of environmental change for human migration have gained increasing attention in the context of climate change and recent large-scale natural disasters, but as yet relatively few large-scale and quantitative studies have addressed this issue. We investigate the consequences of climate-related natural disasters for long-term population mobility in rural Bangladesh, a region particularly vulnerable to environmental change, using longitudinal survey data from 1,700 households spanning a 15-y period. Multivariate event history models are used to estimate the effects of flooding and crop failures on local population mobility and long-distance migration while controlling for a large set of potential confounders at various scales. The results indicate that flooding has modest effects on mobility that are most visible at moderate intensities and for women and the poor. However, crop failures unrelated to flooding have strong effects on mobility in which households that are not directly affected but live in severely affected areas are the most likely to move. These results point toward an alternate paradigm of disaster-induced mobility that recognizes the significant barriers to migration for vulnerable households as well their substantial local adaptive capacity.

Virus infection mediates the effects of elevated CO2 on plants and vectors.

PubMed

Trębicki, Piotr; Vandegeer, Rebecca K; Bosque-Pérez, Nilsa A; Powell, Kevin S; Dader, Beatriz; Freeman, Angela J; Yen, Alan L; Fitzgerald, Glenn J; Luck, Jo E

2016-03-04

Atmospheric carbon dioxide (CO2) concentration has increased significantly and is projected to double by 2100. To increase current food production levels, understanding how pests and diseases respond to future climate driven by increasing CO2 is imperative. We investigated the effects of elevated CO2 (eCO2) on the interactions among wheat (cv. Yitpi), Barley yellow dwarf virus and an important pest and virus vector, the bird cherry-oat aphid (Rhopalosiphum padi), by examining aphid life history, feeding behavior and plant physiology and biochemistry. Our results showed for the first time that virus infection can mediate effects of eCO2 on plants and pathogen vectors. Changes in plant N concentration influenced aphid life history and behavior, and N concentration was affected by virus infection under eCO2. We observed a reduction in aphid population size and increased feeding damage on noninfected plants under eCO2 but no changes to population and feeding on virus-infected plants irrespective of CO2 treatment. We expect potentially lower future aphid populations on noninfected plants but no change or increased aphid populations on virus-infected plants therefore subsequent virus spread. Our findings underscore the complexity of interactions between plants, insects and viruses under future climate with implications for plant disease epidemiology and crop production.

Environmental fluctuations restrict eco-evolutionary dynamics in predator-prey system.

PubMed

Hiltunen, Teppo; Ayan, Gökçe B; Becks, Lutz

2015-06-07

Environmental fluctuations, species interactions and rapid evolution are all predicted to affect community structure and their temporal dynamics. Although the effects of the abiotic environment and prey evolution on ecological community dynamics have been studied separately, these factors can also have interactive effects. Here we used bacteria-ciliate microcosm experiments to test for eco-evolutionary dynamics in fluctuating environments. Specifically, we followed population dynamics and a prey defence trait over time when populations were exposed to regular changes of bottom-up or top-down stressors, or combinations of these. We found that the rate of evolution of a defence trait was significantly lower in fluctuating compared with stable environments, and that the defence trait evolved to lower levels when two environmental stressors changed recurrently. The latter suggests that top-down and bottom-up changes can have additive effects constraining evolutionary response within populations. The differences in evolutionary trajectories are explained by fluctuations in population sizes of the prey and the predator, which continuously alter the supply of mutations in the prey and strength of selection through predation. Thus, it may be necessary to adopt an eco-evolutionary perspective on studies concerning the evolution of traits mediating species interactions. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Virus infection mediates the effects of elevated CO2 on plants and vectors

PubMed Central

Trębicki, Piotr; Vandegeer, Rebecca K.; Bosque-Pérez, Nilsa A.; Powell, Kevin S.; Dader, Beatriz; Freeman, Angela J.; Yen, Alan L.; Fitzgerald, Glenn J.; Luck, Jo E.

2016-01-01

Atmospheric carbon dioxide (CO2) concentration has increased significantly and is projected to double by 2100. To increase current food production levels, understanding how pests and diseases respond to future climate driven by increasing CO2 is imperative. We investigated the effects of elevated CO2 (eCO2) on the interactions among wheat (cv. Yitpi), Barley yellow dwarf virus and an important pest and virus vector, the bird cherry-oat aphid (Rhopalosiphum padi), by examining aphid life history, feeding behavior and plant physiology and biochemistry. Our results showed for the first time that virus infection can mediate effects of eCO2 on plants and pathogen vectors. Changes in plant N concentration influenced aphid life history and behavior, and N concentration was affected by virus infection under eCO2. We observed a reduction in aphid population size and increased feeding damage on noninfected plants under eCO2 but no changes to population and feeding on virus-infected plants irrespective of CO2 treatment. We expect potentially lower future aphid populations on noninfected plants but no change or increased aphid populations on virus-infected plants therefore subsequent virus spread. Our findings underscore the complexity of interactions between plants, insects and viruses under future climate with implications for plant disease epidemiology and crop production. PMID:26941044

HOW THE U.S. PRISON BOOM HAS CHANGED THE AGE DISTRIBUTION OF THE PRISON POPULATION*

PubMed Central

PORTER, LAUREN C.; BUSHWAY, SHAWN D.; TSAO, HUI-SHIEN; SMITH, HERBERT L.

2017-01-01

This article provides a demographic exposition of the changes in the U.S prison population during the period of mass incarceration that began in the late twentieth century. By drawing on data from the Survey of Inmates in State Correctional Facilities (1974–2004) for inmates 17–72 years of age (N = 336), we show that the age distribution shifted upward dramatically: Only 16 percent of the state prison population was 40 years old or older in 1974; by 2004, this percentage had doubled to 33 percent with the median age of prisoners rising from 27 to 34 years old. By using an estimable function approach, we find that the change in the age distribution of the prison population is primarily a cohort effect that is driven by the “enhanced” penal careers of the cohorts who hit young adulthood—the prime age of both crime and incarceration—when substance use was at its peak. Period-specific factors (e.g., proclivity for punishment and incidence of offense) do matter, but they seem to play out more across the life cycles of persons most affected in young adulthood (cohort effects) than across all age groups at one point in time (period effects). PMID:28936228

Environmental effects on the structure of the G-matrix.

PubMed

Wood, Corlett W; Brodie, Edmund D

2015-11-01

Genetic correlations between traits determine the multivariate response to selection in the short term, and thereby play a causal role in evolutionary change. Although individual studies have documented environmentally induced changes in genetic correlations, the nature and extent of environmental effects on multivariate genetic architecture across species and environments remain largely uncharacterized. We reviewed the literature for estimates of the genetic variance-covariance (G) matrix in multiple environments, and compared differences in G between environments to the divergence in G between conspecific populations (measured in a common garden). We found that the predicted evolutionary trajectory differed as strongly between environments as it did between populations. Between-environment differences in the underlying structure of G (total genetic variance and the relative magnitude and orientation of genetic correlations) were equal to or greater than between-population differences. Neither environmental novelty, nor the difference in mean phenotype predicted these differences in G. Our results suggest that environmental effects on multivariate genetic architecture may be comparable to the divergence that accumulates over dozens or hundreds of generations between populations. We outline avenues of future research to address the limitations of existing data and characterize the extent to which lability in genetic correlations shapes evolution in changing environments. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

Virus infection mediates the effects of elevated CO2 on plants and vectors

NASA Astrophysics Data System (ADS)

Trębicki, Piotr; Vandegeer, Rebecca K.; Bosque-Pérez, Nilsa A.; Powell, Kevin S.; Dader, Beatriz; Freeman, Angela J.; Yen, Alan L.; Fitzgerald, Glenn J.; Luck, Jo E.

2016-03-01

Atmospheric carbon dioxide (CO2) concentration has increased significantly and is projected to double by 2100. To increase current food production levels, understanding how pests and diseases respond to future climate driven by increasing CO2 is imperative. We investigated the effects of elevated CO2 (eCO2) on the interactions among wheat (cv. Yitpi), Barley yellow dwarf virus and an important pest and virus vector, the bird cherry-oat aphid (Rhopalosiphum padi), by examining aphid life history, feeding behavior and plant physiology and biochemistry. Our results showed for the first time that virus infection can mediate effects of eCO2 on plants and pathogen vectors. Changes in plant N concentration influenced aphid life history and behavior, and N concentration was affected by virus infection under eCO2. We observed a reduction in aphid population size and increased feeding damage on noninfected plants under eCO2 but no changes to population and feeding on virus-infected plants irrespective of CO2 treatment. We expect potentially lower future aphid populations on noninfected plants but no change or increased aphid populations on virus-infected plants therefore subsequent virus spread. Our findings underscore the complexity of interactions between plants, insects and viruses under future climate with implications for plant disease epidemiology and crop production.

Acid rain recovery may help to mitigate the impacts of climate change on thermally sensitive fish in lakes across eastern North America.

PubMed

Warren, Dana R; Kraft, Clifford E; Josephson, Daniel C; Driscoll, Charles T

2017-06-01

From the 1970s to 1990s, more stringent air quality regulations were implemented across North America and Europe to reduce chemical emissions that contribute to acid rain. Surface water pH slowly increased during the following decades, but biological recovery lagged behind chemical recovery. Fortunately, this situation is changing. In the past few years, northeastern US fish populations have begun to recover in lakes that were historically incapable of sustaining wild fish due to acidic conditions. As lake ecosystems across the eastern United States recover from acid deposition, the stress to the most susceptible populations of native coldwater fish appears to be shifting from acidification effects to thermal impacts associated with changing climate. Extreme summer temperature events - which are expected to occur with increasing frequency in the coming century - can stress and ultimately kill native coldwater fish in lakes where thermal stratification is absent or highly limited. Based on data from northeastern North America, we argue that recovery from acid deposition has the potential to improve the resilience of coldwater fish populations in some lakes to impacts of climate change. This will occur as the amount of dissolved organic carbon (DOC) in the water increases with increasing lake pH. Increased DOC will reduce water clarity and lead to shallower and more persistent lake thermoclines that can provide larger areas of coldwater thermal refuge habitat. Recovery from acidification will not eliminate the threat of climate change to coldwater fish, but secondary effects of acid recovery may improve the resistance of coldwater fish populations in lakes to the effects of elevated summer temperatures in historically acidified ecosystems. This analysis highlights the importance of considering the legacy of past ecosystem impacts and how recovery or persistence of those effects may interact with climate change impacts on biota in the coming decades. © 2016 John Wiley & Sons Ltd.

Density effect on great tit (Parus major) clutch size intensifies in a polluted environment.

PubMed

Eeva, Tapio; Lehikoinen, Esa

2013-12-01

Long-term data on a great tit (Parus major) population breeding in a metal-polluted zone around a copper-nickel smelter indicate that, against expectations, the clutch size of this species is decreasing even though metal emissions in the area have decreased considerably over the past two decades. Here, we document long-term population-level changes in the clutch size of P. major and explore if changes in population density, population numbers of competing species, timing of breeding, breeding habitat, or female age distribution can explain decreasing clutch sizes. Clutch size of P. major decreased by one egg in the polluted zone during the past 21 years, while there was no significant change in clutch size in the unpolluted reference zone over this time period. Density of P. major nests was similar in both environments but increased threefold during the study period in both areas (from 0.8 to 2.4 nest/ha). In the polluted zone, clutch size has decreased as a response to a considerable increase in population density, while a corresponding density change in the unpolluted zone did not have such an effect. The other factors studied did not explain the clutch size trend. Fledgling numbers in the polluted environment have been relatively low since the beginning of the study period, and they do not show a corresponding decrease to that noted for the clutch size over the same time period. Our study shows that responses of commonly measured life-history parameters to anthropogenic pollution depend on the structure of the breeding population. Interactions between pollution and intrinsic population characters should therefore be taken into account in environmental studies.

Do we need demographic data to forecast plant population dynamics?

USGS Publications Warehouse

Tredennick, Andrew T.; Hooten, Mevin B.; Adler, Peter B.

2017-01-01

Rapid environmental change has generated growing interest in forecasts of future population trajectories. Traditional population models built with detailed demographic observations from one study site can address the impacts of environmental change at particular locations, but are difficult to scale up to the landscape and regional scales relevant to management decisions. An alternative is to build models using population-level data that are much easier to collect over broad spatial scales than individual-level data. However, it is unknown whether models built using population-level data adequately capture the effects of density-dependence and environmental forcing that are necessary to generate skillful forecasts.Here, we test the consequences of aggregating individual responses when forecasting the population states (percent cover) and trajectories of four perennial grass species in a semi-arid grassland in Montana, USA. We parameterized two population models for each species, one based on individual-level data (survival, growth and recruitment) and one on population-level data (percent cover), and compared their forecasting accuracy and forecast horizons with and without the inclusion of climate covariates. For both models, we used Bayesian ridge regression to weight the influence of climate covariates for optimal prediction.In the absence of climate effects, we found no significant difference between the forecast accuracy of models based on individual-level data and models based on population-level data. Climate effects were weak, but increased forecast accuracy for two species. Increases in accuracy with climate covariates were similar between model types.In our case study, percent cover models generated forecasts as accurate as those from a demographic model. For the goal of forecasting, models based on aggregated individual-level data may offer a practical alternative to data-intensive demographic models. Long time series of percent cover data already exist for many plant species. Modelers should exploit these data to predict the impacts of environmental change.

78 FR 65248 - Endangered and Threatened Wildlife and Plants; Threatened Status for the Distinct Population...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-31

... effects of climate change on wolverines in the future. Our assessment of climate change impacts on wolverines used wolverines' snow dependence and suitable wolverine habitat and climate change models to predict future impacts of climate change on wolverine habitat suitability. Some of the commenters...

Preparing for climate change: Forestry and assisted migration

Treesearch

Mary I. Williams; R. Kasten Dumroese

2013-01-01

Although plants have moved across the landscape in response to changing climate for millennia, projections of contemporary climate change suggest that forest tree species and populations will need to migrate faster than their natural ability. Therefore, climate change adaptation strategies, such as assisted migration, have gained attention since 2007. Effective...

Improving Undergraduate Climate Change Literacy through Writing: A Pilot Study

ERIC Educational Resources Information Center

Small Griswold, Jennifer D.

2017-01-01

A climate-literate population, capable of making informed decisions related to climate change, is of critical importance as society faces ever-increasing global temperatures and changes in the climate system. This project evaluates the effectiveness of a novel instructional approach that incorporates climate change science into a first-year…

Global change effects on plant-insect interactions: The role of phytochemistry

Treesearch

Mary A. Jamieson; Laura A. Burkle; Jessamyn S. Manson; Justin B. Runyon; Amy M. Trowbridge; Joseph Zientek

2017-01-01

Natural and managed ecosystems are undergoing rapid environmental change due to a growing human population and associated increases in industrial and agricultural activity. Global environmental change directly and indirectly impacts insect herbivores and pollinators. In this review, we highlight recent research examining how environmental change factors affect plant...

Effects of enhanced UV-B radiation on secondary metabolites in forage plants and potential consequences for multiple trophic responses involving mammalian herbivores

NASA Astrophysics Data System (ADS)

Thines, Nicole J.; Bassman, John H.; Shipley, Lisa A.; Slusser, James R.

2004-10-01

Herbivores represent the interface between primary production and higher trophic levels. The effects of enhanced UV-B radiation on microbes, invertebrate herbivores, and detritivores has received limited study in both terrestrial and aquatic ecosystems. However, although direct effects (e.g. melanoma, cataracts) on mammals have been documented, indirect effects (e.g., resulting from changes in plant chemistry) of enhanced UV-B on mammalian herbivores have not been evaluated. Although the diet of mammalian herbivores has little effect on nutritional quality for their associated predators, to the extent changes in plant chemistry affect aspects of population dynamics (e.g., growth, fecundity, densities), higher trophic levels can be affected. In this study, different forage species of varying inherent levels of key secondary metabolites are being grown in the field under either ambient or ambient plus supplemental UV-B radiation simulating a 15% stratospheric ozone depletion for Pullman, Washington. At various time intervals, foliage is being sampled and analyzed for changes in secondary metabolites and other attributes. Using controlled feeding trials, changes in plant secondary metabolites are being related to preference and digestibility in specialist and generalist mammalian hindgut herbivores, digestion in ruminants and non-ruminants, and to selected aspects of population dynamics in mammalian herbivores. Results suggest how UV-B-induced changes in plant secondary chemistry affect animal nutrition, and thus animal productivity in a range of mammalian herbivores. Reductions in palatability and digestibility of plant material along with reductions in fecundity and other aspects of population dynamics could have significant economic ramifications for farmers, ranchers and wildlife biologists.

Synchrony of Piping Plover breeding populations in the U.S. Northern Great Plains

USGS Publications Warehouse

Roche, Erin A.; Shaffer, Terry L.; Dovichin, Colin M.; Sherfy, Mark H.; Anteau, Michael J.; Wiltermuth, Mark T.

2016-01-01

Local populations that fluctuate synchronously are at a greater risk of extinction than those that do not. The closer the geographic proximity of populations, the more prone they are to synchronizing. Shorebird species select habitat broadly, and many breed across regions with diverse nesting habitat types. Under these conditions, nearby populations may experience conditions sufficiently different to prevent population synchrony, despite dispersal. In the U.S. Northern Great Plains, the Piping Plover (Charadrius melodus), federally listed as Threatened, is a migratory shorebird species that nests on the shorelines of rivers, reservoirs, and alkaline lakes. We assessed the degree to which local plover breeding population abundances were correlated (population synchrony), changed over time (population stability), and were influenced by environmental factors such as available habitat, precipitation, and within-season reservoir level rise. We found that the abundances of breeding populations nesting in riverine and reservoir habitats were the most synchronous, while populations nesting in alkaline lake habitats exhibited the greatest stability. Changes in local breeding population abundances were not explained by a single factor across habitat types. However, the abundances of local populations nesting in alkaline lake and river shoreline habitats were positively correlated with changes in nesting habitat availability. Our results suggest that dispersal among populations nesting in either river or reservoir and alkaline lake shoreline habitat may have an overall stabilizing effect on the persistence of the Great Plains Piping Plover metapopulation.

Ecomorphology of the external flight apparatus of blackcaps (Sylvia atricapilla) with different migration behavior.

PubMed

Fiedler, Wolfgang

2005-06-01

An analysis of the external flight apparatus of 700 blackcaps from eight different populations (sedentary to long-distance migrators) is presented. With increasing migration distances of populations, (1) wing length, aspect ratio, and wing pointedness increase; (2) wing load decreases; (3) slots on the wing tips become relatively shorter; (4) the alula tends to be shorter in relation to wing length; and (5) the tail is shorter in relation to wing length. Although body mass increases from southern to northern populations, changes in wing length and wing area are two to three times larger than expected for simple isometric relationships. Regarding the aerodynamic background of these changes, it can be stated that traits for energy-effective flight are more strongly developed and traits for maneuverability are less developed in birds traveling longer distances, presumably as a consequence of trade-offs. Nonmigratory blackcaps from Madeira and the Cape Verde islands do not always show the traits we would expect in view of their sedentary behavior. This can be seen as a result of recent colonization of these islands by migrants or of selection by factors other than migration behavior. In migratory populations, changes between the first and the second set of primaries during first complete molt show almost the same pattern as the changes from nonmigratory to migratory populations. During molt of the primaries, blackcaps of nonmigratory populations do not show these changes. Hybrids between migrating and nonmigrating blackcap populations (Moscow and Madeira) showed intermediate values between parent populations in wing length, wing shape, and wing area; in the other variables they resembled either parent population.

Productivity responses of a widespread marine piscivore, Gadus morhua, to oceanic thermal extremes and trends.

PubMed

Mantzouni, Irene; MacKenzie, Brian R

2010-06-22

Climate change will have major consequences for population dynamics and life histories of marine biota as it progresses in the twenty-first century. These impacts will differ in magnitude and direction for populations within individual marine species whose geographical ranges span large gradients in latitude and temperature. Here we use meta-analytical methods to investigate how recruitment (i.e. the number of new fish produced by spawners in a given year which subsequently grow and survive to become vulnerable to fishing gear) has reacted to temperature fluctuations, and in particular to extremes of temperature, in cod populations throughout the north Atlantic. Temperature has geographically explicit effects on cod recruitment. Impacts differ depending on whether populations are located in the upper (negative effects) or in the lower (positive effects) thermal range. The probabilities of successful year-classes in populations living in warm areas is on average 34 per cent higher in cold compared with warm seasons, whereas opposite patterns exist for populations living in cold areas. These results have implications for cod dynamics, distributions and phenologies under the influence of ocean warming, particularly related to not only changes in the mean temperature, but also its variability (e.g. frequency of exceptionally cold or warm seasons).

Cumulative effects of climate and landscape change drive spatial distribution of Rocky Mountain wolverine (Gulo gulo L.).

PubMed

Heim, Nicole; Fisher, Jason T; Clevenger, Anthony; Paczkowski, John; Volpe, John

2017-11-01

Contemporary landscapes are subject to a multitude of human-derived stressors. Effects of such stressors are increasingly realized by population declines and large-scale extirpation of taxa worldwide. Most notably, cumulative effects of climate and landscape change can limit species' local adaptation and dispersal capabilities, thereby reducing realized niche space and range extent. Resolving the cumulative effects of multiple stressors on species persistence is a pressing challenge in ecology, especially for declining species. For example, wolverines ( Gulo gulo L.) persist on only 40% of their historic North American range. While climate change has been shown to be a mechanism of range retractions, anthropogenic landscape disturbance has been recently implicated. We hypothesized these two interact to effect declines. We surveyed wolverine occurrence using camera trapping and genetic tagging at 104 sites at the wolverine range edge, spanning a 15,000 km 2 gradient of climate, topographic, anthropogenic, and biotic variables. We used occupancy and generalized linear models to disentangle the factors explaining wolverine distribution. Persistent spring snow pack-expected to decrease with climate change-was a significant predictor, but so was anthropogenic landscape change. Canid mesocarnivores, which we hypothesize are competitors supported by anthropogenic landscape change, had comparatively weaker effect. Wolverine population declines and range shifts likely result from climate change and landscape change operating in tandem. We contend that similar results are likely for many species and that research that simultaneously examines climate change, landscape change, and the biotic landscape is warranted. Ecology research and species conservation plans that address these interactions are more likely to meet their objectives.

Lake Michigan: Man's effects on native fish stocks and other biota

USGS Publications Warehouse

Wells, LaRue; McLain, Alberton L.

1973-01-01

Exploitation was largely responsible for the changes in Lake Michigan fish stocks before the invasion of the smelt, and probably before the invasion of the sea lamprey. The lamprey and alewife, however, have exerted a greater impact than the fishery on native fish populations in recent decades. Accelerated eutrophication and other pollution, although important, have not equalled the other factors in causing changes in native fish populations.

The sociology of landowner interest in restoring fire-adapted, biodiverse habitats in the wildland-urban interface of Oregon's Willamette Valley ecoregion

Treesearch

Max Nielsen-Pincus; Robert G. Ribe; Bart R. Johnson

2011-01-01

In many parts of the world, the combined effects of wildfire, climate change, and population growth in the wildland-urban interface pose increasing risks to both people and biodiversity. These risks are exemplified in western Oregon's Willamette Valley Ecoregion, where population is projected to double by 2050 and climate change is expected to increase wildfire...

Reconstructing shifts in vital rates driven by long-term environmental change: a new demographic method based on readily available data.

PubMed

González, Edgar J; Martorell, Carlos

2013-07-01

Frequently, vital rates are driven by directional, long-term environmental changes. Many of these are of great importance, such as land degradation, climate change, and succession. Traditional demographic methods assume a constant or stationary environment, and thus are inappropriate to analyze populations subject to these changes. They also require repeat surveys of the individuals as change unfolds. Methods for reconstructing such lengthy processes are needed. We present a model that, based on a time series of population size structures and densities, reconstructs the impact of directional environmental changes on vital rates. The model uses integral projection models and maximum likelihood to identify the rates that best reconstructs the time series. The procedure was validated with artificial and real data. The former involved simulated species with widely different demographic behaviors. The latter used a chronosequence of populations of an endangered cactus subject to increasing anthropogenic disturbance. In our simulations, the vital rates and their change were always reconstructed accurately. Nevertheless, the model frequently produced alternative results. The use of coarse knowledge of the species' biology (whether vital rates increase or decrease with size or their plausible values) allowed the correct rates to be identified with a 90% success rate. With real data, the model correctly reconstructed the effects of disturbance on vital rates. These effects were previously known from two populations for which demographic data were available. Our procedure seems robust, as the data violated several of the model's assumptions. Thus, time series of size structures and densities contain the necessary information to reconstruct changing vital rates. However, additional biological knowledge may be required to provide reliable results. Because time series of size structures and densities are available for many species or can be rapidly generated, our model can contribute to understand populations that face highly pressing environmental problems.

Reconstructing shifts in vital rates driven by long-term environmental change: a new demographic method based on readily available data

PubMed Central

González, Edgar J; Martorell, Carlos

2013-01-01

Frequently, vital rates are driven by directional, long-term environmental changes. Many of these are of great importance, such as land degradation, climate change, and succession. Traditional demographic methods assume a constant or stationary environment, and thus are inappropriate to analyze populations subject to these changes. They also require repeat surveys of the individuals as change unfolds. Methods for reconstructing such lengthy processes are needed. We present a model that, based on a time series of population size structures and densities, reconstructs the impact of directional environmental changes on vital rates. The model uses integral projection models and maximum likelihood to identify the rates that best reconstructs the time series. The procedure was validated with artificial and real data. The former involved simulated species with widely different demographic behaviors. The latter used a chronosequence of populations of an endangered cactus subject to increasing anthropogenic disturbance. In our simulations, the vital rates and their change were always reconstructed accurately. Nevertheless, the model frequently produced alternative results. The use of coarse knowledge of the species' biology (whether vital rates increase or decrease with size or their plausible values) allowed the correct rates to be identified with a 90% success rate. With real data, the model correctly reconstructed the effects of disturbance on vital rates. These effects were previously known from two populations for which demographic data were available. Our procedure seems robust, as the data violated several of the model's assumptions. Thus, time series of size structures and densities contain the necessary information to reconstruct changing vital rates. However, additional biological knowledge may be required to provide reliable results. Because time series of size structures and densities are available for many species or can be rapidly generated, our model can contribute to understand populations that face highly pressing environmental problems. PMID:23919169

Natural selection on thermal performance in a novel thermal environment

PubMed Central

Logan, Michael L.; Cox, Robert M.; Calsbeek, Ryan

2014-01-01

Tropical ectotherms are thought to be especially vulnerable to climate change because they are adapted to relatively stable temperature regimes, such that even small increases in environmental temperature may lead to large decreases in physiological performance. One way in which tropical organisms may mitigate the detrimental effects of warming is through evolutionary change in thermal physiology. The speed and magnitude of this response depend, in part, on the strength of climate-driven selection. However, many ectotherms use behavioral adjustments to maintain preferred body temperatures in the face of environmental variation. These behaviors may shelter individuals from natural selection, preventing evolutionary adaptation to changing conditions. Here, we mimic the effects of climate change by experimentally transplanting a population of Anolis sagrei lizards to a novel thermal environment. Transplanted lizards experienced warmer and more thermally variable conditions, which resulted in strong directional selection on thermal performance traits. These same traits were not under selection in a reference population studied in a less thermally stressful environment. Our results indicate that climate change can exert strong natural selection on tropical ectotherms, despite their ability to thermoregulate behaviorally. To the extent that thermal performance traits are heritable, populations may be capable of rapid adaptation to anthropogenic warming. PMID:25225361

Natural selection on thermal performance in a novel thermal environment.

PubMed

Logan, Michael L; Cox, Robert M; Calsbeek, Ryan

2014-09-30

Tropical ectotherms are thought to be especially vulnerable to climate change because they are adapted to relatively stable temperature regimes, such that even small increases in environmental temperature may lead to large decreases in physiological performance. One way in which tropical organisms may mitigate the detrimental effects of warming is through evolutionary change in thermal physiology. The speed and magnitude of this response depend, in part, on the strength of climate-driven selection. However, many ectotherms use behavioral adjustments to maintain preferred body temperatures in the face of environmental variation. These behaviors may shelter individuals from natural selection, preventing evolutionary adaptation to changing conditions. Here, we mimic the effects of climate change by experimentally transplanting a population of Anolis sagrei lizards to a novel thermal environment. Transplanted lizards experienced warmer and more thermally variable conditions, which resulted in strong directional selection on thermal performance traits. These same traits were not under selection in a reference population studied in a less thermally stressful environment. Our results indicate that climate change can exert strong natural selection on tropical ectotherms, despite their ability to thermoregulate behaviorally. To the extent that thermal performance traits are heritable, populations may be capable of rapid adaptation to anthropogenic warming.

Degrees of Isolation: The Impact of Climate Change on the Dispersal and Population Genetic Structure of Two Antarctic Fish Species

NASA Astrophysics Data System (ADS)

Young, E. F.; Belchier, M.; Meredith, M. P.; Tysklind, N.; Carvalho, G. R.

2016-02-01

Understanding the key drivers of larval dispersal and population connectivity in the marine environment is essential for estimating the potential impacts of climate change on the genetic structure and resilience of populations. Small, isolated and fragmented communities will differ fundamentally in their response and resilience to environmental stress, compared with species that are broadly distributed, abundant, and with a frequent exchange of members. Using a `seascape genetics' approach, combining oceanographic modelling and genetic analyses, we have elucidated the fundamental roles of oceanographic transport and planktonic duration on the connectivity and population genetic structure of two Antarctic fish species with contrasting early life histories, Champsocephalus gunnari and Notothenia rossii. Here, we extend these analyses to consider the impact of rising sea temperatures due to climate change on planktonic dispersal and population connectivity. Using a theoretical approach, the effect of increased water temperatures on mortality rates and species-specific egg and larval phase durations has been incorporated into the models, and the relative impact of these climate-related influences on connectivity and population genetic structure has been investigated. Here we present the key findings of our research and consider the roles of early life history and oceanography in the response of fragmented fish populations to climate change.

Slowly switching between environments facilitates reverse evolution in small populations.

PubMed

Tan, Longzhi; Gore, Jeff

2012-10-01

Natural populations must constantly adapt to ever-changing environmental conditions. A particularly interesting question is whether such adaptations can be reversed by returning the population to an ancestral environment. Such evolutionary reversals have been observed in both natural and laboratory populations. However, the factors that determine the reversibility of evolution are still under debate. The time scales of environmental change vary over a wide range, but little is known about how the rate of environmental change influences the reversibility of evolution. Here, we demonstrate computationally that slowly switching between environments increases the reversibility of evolution for small populations that are subject to only modest clonal interference. For small populations, slow switching reduces the mean number of mutations acquired in a new environment and also increases the probability of reverse evolution at each of these "genetic distances." As the population size increases, slow switching no longer reduces the genetic distance, thus decreasing the evolutionary reversibility. We confirm this effect using both a phenomenological model of clonal interference and also a Wright-Fisher stochastic simulation that incorporates genetic diversity. Our results suggest that the rate of environmental change is a key determinant of the reversibility of evolution, and provides testable hypotheses for experimental evolution. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

A Theoretical Lower Bound for Selection on the Expression Levels of Proteins

DOE PAGES

Price, Morgan N.; Arkin, Adam P.

2016-06-11

We use simple models of the costs and benefits of microbial gene expression to show that changing a protein's expression away from its optimum by 2-fold should reduce fitness by at least [Formula: see text], where P is the fraction the cell's protein that the gene accounts for. As microbial genes are usually expressed at above 5 parts per million, and effective population sizes are likely to be above 10(6), this implies that 2-fold changes to gene expression levels are under strong selection, as [Formula: see text], where Ne is the effective population size and s is the selection coefficient.more » Thus, most gene duplications should be selected against. On the other hand, we predict that for most genes, small changes in the expression will be effectively neutral.« less

Tax reform, population ageing and the changing labour supply behaviour of married women.

PubMed

Apps, P

1991-01-01

"The burden of financing retirement incomes in an ageing population is predicted to rise sharply in future decades. This paper investigates the effects of reforms to the Australian tax-benefit system involving a greater reliance on proportional taxation for raising revenue and a more targeted welfare system for cutting government expenditure, in order to reduce expected budget deficits. Estimates of changes in net incomes and hours of work suggest that reforms of this kind shift the tax burden to lower and middle income households with a second earner and that they can have counter-productive labour supply effects. The study explores the impact of projected increases in female work force participation and illustrates the importance of shifts in the labour supply of married women in predicting the fiscal effects of demographic change." excerpt

A Theoretical Lower Bound for Selection on the Expression Levels of Proteins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Price, Morgan N.; Arkin, Adam P.

We use simple models of the costs and benefits of microbial gene expression to show that changing a protein's expression away from its optimum by 2-fold should reduce fitness by at least [Formula: see text], where P is the fraction the cell's protein that the gene accounts for. As microbial genes are usually expressed at above 5 parts per million, and effective population sizes are likely to be above 10(6), this implies that 2-fold changes to gene expression levels are under strong selection, as [Formula: see text], where Ne is the effective population size and s is the selection coefficient.more » Thus, most gene duplications should be selected against. On the other hand, we predict that for most genes, small changes in the expression will be effectively neutral.« less

Impacts of invasive fish removal through angling on population characteristics and juvenile growth rate.

PubMed

Evangelista, Charlotte; Britton, Robert J; Cucherousset, Julien

2015-06-01

Exploitation can modify the characteristics of fish populations through the selective harvesting of individuals, with this potentially leading to rapid ecological and evolutionary changes. Despite the well-known effects of invasive fishes on aquatic ecosystems generally, the potential effects of their selective removal through angling, a strategy commonly used to manage invasive fish, are poorly understood. The aim of this field-based study was to use the North American pumpkinseed Lepomis gibbosus as the model species to investigate the consequences of selective removal on their population characteristics and juvenile growth rates across 10 populations in artificial lakes in southern France. We found that the maximal individual mass in populations decreased as removal pressure through angling increased, whereas we did not observed any changes in the maximal individual length in populations as removal pressure increased. Total population abundance did not decrease as removal pressure increased; instead, here was a U-shaped relationship between removal pressure and the abundance of medium-bodied individuals. In addition, population biomass had a U-shaped curve response to removal pressure, implying that invasive fish populations can modulate their characteristics to compensate for the negative effects of selective removals. In addition, individual lengths at age 2 and juvenile growth rates decreased as removal pressure through angling increased, suggesting a shift toward an earlier size at maturity and an overall slower growing phenotype. Therefore, these outputs challenge the efficiency of selective management methods, suggesting the use of more proactive strategies to control invasive populations, and the need to investigate the potential ecological and evolutionary repercussions of nonrandom removal.

Impacts of invasive fish removal through angling on population characteristics and juvenile growth rate

PubMed Central

Evangelista, Charlotte; Britton, Robert J; Cucherousset, Julien

2015-01-01

Exploitation can modify the characteristics of fish populations through the selective harvesting of individuals, with this potentially leading to rapid ecological and evolutionary changes. Despite the well-known effects of invasive fishes on aquatic ecosystems generally, the potential effects of their selective removal through angling, a strategy commonly used to manage invasive fish, are poorly understood. The aim of this field-based study was to use the North American pumpkinseed Lepomis gibbosus as the model species to investigate the consequences of selective removal on their population characteristics and juvenile growth rates across 10 populations in artificial lakes in southern France. We found that the maximal individual mass in populations decreased as removal pressure through angling increased, whereas we did not observed any changes in the maximal individual length in populations as removal pressure increased. Total population abundance did not decrease as removal pressure increased; instead, here was a U-shaped relationship between removal pressure and the abundance of medium-bodied individuals. In addition, population biomass had a U-shaped curve response to removal pressure, implying that invasive fish populations can modulate their characteristics to compensate for the negative effects of selective removals. In addition, individual lengths at age 2 and juvenile growth rates decreased as removal pressure through angling increased, suggesting a shift toward an earlier size at maturity and an overall slower growing phenotype. Therefore, these outputs challenge the efficiency of selective management methods, suggesting the use of more proactive strategies to control invasive populations, and the need to investigate the potential ecological and evolutionary repercussions of nonrandom removal. PMID:26078856

Effects of levomilnacipran extended-release on motivation/energy and functioning in adults with major depressive disorder.

PubMed

Thase, Michael E; Gommoll, Carl; Chen, Changzheng; Kramer, Kenneth; Sambunaris, Angelo

2016-11-01

The objective of this post-hoc analysis was to investigate the relationship between motivation/energy and functional impairment in patients with major depressive disorder (MDD). Data were taken from a phase 3 trial of levomilnacipran extended-release (ER) in adults with MDD (NCT01034462; N=429) that used the 18-item Motivation and Energy Inventory (MEI) to assess motivation/energy. Two subgroups with lower and higher motivation/energy were defined using baseline MEI total scores (≤28 and >28, respectively). Change from baseline in the Sheehan Disability Scale (SDS) total score was analyzed in the intent-to-treat (ITT) population and both subgroups. Path analyses were carried out in the ITT population and a lower MEI subgroup to assess the direct and indirect effects of levomilnacipran ER on SDS total score change. In the ITT population and the lower MEI subgroup, significant differences were found between levomilnacipran ER and placebo for changes in the SDS total score (-2.6 and -3.9, both P<0.01), but not in the higher MEI subgroup. The indirect effect of levomilnacipran ER on SDS total score improvement, as mediated by MEI total score change, was 79.9% in the lower MEI subgroup and 67.2% in the ITT population. Levomilnacipran ER was previously shown to improve motivation/energy in adults with MDD. The current analysis indicates that improvements in functional impairment were considerably mediated by improvements in motivation/energy, particularly in patients with lower motivation/energy at baseline.

Increased natural mortality at low abundance can generate an Allee effect in a marine fish.

PubMed

Kuparinen, Anna; Hutchings, Jeffrey A

2014-10-01

Negative density-dependent regulation of population dynamics promotes population growth at low abundance and is therefore vital for recovery following depletion. Inversely, any process that reduces the compensatory density-dependence of population growth can negatively affect recovery. Here, we show that increased adult mortality at low abundance can reverse compensatory population dynamics into its opposite-a demographic Allee effect. Northwest Atlantic cod (Gadus morhua) stocks collapsed dramatically in the early 1990s and have since shown little sign of recovery. Many experienced dramatic increases in natural mortality, ostensibly attributable in some populations to increased predation by seals. Our findings show that increased natural mortality of a magnitude observed for overfished cod stocks has been more than sufficient to fundamentally alter the dynamics of density-dependent population regulation. The demographic Allee effect generated by these changes can slow down or even impede the recovery of depleted populations even in the absence of fishing.

Life cycle ecophysiology of small pelagic fish and climate-driven changes in populations

NASA Astrophysics Data System (ADS)

Peck, Myron A.; Reglero, Patricia; Takahashi, Motomitsu; Catalán, Ignacio A.

2013-09-01

Due to their population characteristics and trophodynamic role, small pelagic fishes are excellent bio-indicators of climate-driven changes in marine systems world-wide. We argue that making robust projections of future changes in the productivity and distribution of small pelagics will require a cause-and-effect understanding of historical changes based upon physiological principles. Here, we reviewed the ecophysiology of small pelagic (clupeiform) fishes including a matrix of abiotic and biotic extrinsic factors (e.g., temperature, salinity, light, and prey characteristics) and stage-specific vital rates: (1) adult spawning, (2) survival and development of eggs and yolk sac larvae, and (3) feeding and growth of larvae, post-larvae and juveniles. Emphasis was placed on species inhabiting Northwest Pacific and Northeast Atlantic (European) waters for which summary papers are particularly scarce compared to anchovy and sardine in upwelling systems. Our review revealed that thermal niches (optimal and sub-optimal ranges in temperatures) were species- and stage-specific but that temperature effects only partly explained observed changes in the distribution and/or productivity of populations in the Northwest Pacific and Northeast Atlantic; changes in temperature may be necessary but not sufficient to induce population-level shifts. Prey availability during the late larval and early juvenile period was a common, density-dependent mechanism linked to fluctuations in populations but recruitment mechanisms were system-specific suggesting that generalizations of climate drivers across systems should be avoided. We identified gaps in knowledge regarding basic elements of the growth physiology of each life stage that will require additional field and laboratory study. Avenues of research are recommended that will aid the development of models that provide more robust, physiological-based projections of the population dynamics of these and other small pelagic fish. In our opinion, the continued development of biophysical models that close the life cycle (depict all life stages) offers the best chance of revealing processes causing historical fluctuations on the productivity and distribution of small pelagic fishes and to project future climate-driven impacts. Correctly representing physiological-based mechanisms will increase confidence in the outcomes of models simulating the potential impacts of bottom-up processes, a first step towards evaluating the mixture of factors and processes (e.g. intra-guild dynamics, predation, fisheries exploitation) which interact with climate to affect populations of small pelagic fishes. Understand the impacts of reduced growth rates during the juvenile stage on the process of maturation and spawning condition of small pelagic fishes. Examine the effects of changes in prey quality on the duration and magnitude of spawning by small pelagic fishes to capture how climate-driven changes in zooplankton species composition might act as a “bottom-up” regulator of fish productivity. Identify the drivers for spawning location and timing to better understand how spawning dynamics may be influenced by climate change (e.g. changes in water salinity or turbidity resulting from changes in river discharges or wind-driven turbulence, respectively).

The non-linear, interactive effects of population density and climate drive the geographical patterns of waterfowl survival

USGS Publications Warehouse

Zhao, Qing; Boomer, G. Scott; Kendall, William L.

2018-01-01

On-going climate change has major impacts on ecological processes and patterns. Understanding the impacts of climate on the geographical patterns of survival can provide insights to how population dynamics respond to climate change and provide important information for the development of appropriate conservation strategies at regional scales. It is challenging to understand the impacts of climate on survival, however, due to the fact that the non-linear relationship between survival and climate can be modified by density-dependent processes. In this study we extended the Brownie model to partition hunting and non-hunting mortalities and linked non-hunting survival to covariates. We applied this model to four decades (1972–2014) of waterfowl band-recovery, breeding population survey, and precipitation and temperature data covering multiple ecological regions to examine the non-linear, interactive effects of population density and climate on waterfowl non-hunting survival at a regional scale. Our results showed that the non-linear effect of temperature on waterfowl non-hunting survival was modified by breeding population density. The concave relationship between non-hunting survival and temperature suggested that the effects of warming on waterfowl survival might be multifaceted. Furthermore, the relationship between non-hunting survival and temperature was stronger when population density was higher, suggesting that high-density populations may be less buffered against warming than low-density populations. Our study revealed distinct relationships between waterfowl non-hunting survival and climate across and within ecological regions, highlighting the importance of considering different conservation strategies according to region-specific population and climate conditions. Our findings and associated novel modelling approach have wide implications in conservation practice.

Climate and population density drive changes in cod body size throughout a century on the Norwegian coast

PubMed Central

Rogers, Lauren A.; Stige, Leif C.; Olsen, Esben M.; Knutsen, Halvor; Chan, Kung-Sik; Stenseth, Nils Chr.

2011-01-01

Understanding how populations respond to changes in climate requires long-term, high-quality datasets, which are rare for marine systems. We estimated the effects of climate warming on cod lengths and length variability using a unique 91-y time series of more than 100,000 individual juvenile cod lengths from surveys that began in 1919 along the Norwegian Skagerrak coast. Using linear mixed-effects models, we accounted for spatial population structure and the nested structure of the survey data to reveal opposite effects of spring and summer warming on juvenile cod lengths. Warm summer temperatures in the coastal Skagerrak have limited juvenile growth. In contrast, warmer springs have resulted in larger juvenile cod, with less variation in lengths within a cohort, possibly because of a temperature-driven contraction in the spring spawning period. A density-dependent reduction in length was evident only at the highest population densities in the time series, which have rarely been observed in the last decade. If temperatures rise because of global warming, nonlinearities in the opposing temperature effects suggest that negative effects of warmer summers will increasingly outweigh positive effects of warmer springs, and the coastal Skagerrak will become ill-suited for Atlantic cod. PMID:21245301

Healthcare organizational change: implications for access to care and its measurement.

PubMed Central

Miller, R. H.

1998-01-01

OBJECTIVES: To summarize evidence from peer-reviewed literature on access to care for vulnerable HMO enrollee populations; to discuss the potential effect of recent HMO and physician organization changes on access to care and its measurement. STUDY DESIGN: Review and summary of peer-reviewed literature for two HMO populations: those with chronic conditions and diseases, and those subject to discrimination due to income, color, or ethnic background. I also reviewed and summarized literature on three major changes in capitated organizations (HMOs and capitated physician organizations) that could affect access to care for vulnerable populations, and summarized findings from healthcare manager interviews conducted for several recent research projects on health system change. PRINCIPAL FINDINGS: Although mixed, there are enough negative results to raise some concerns about access to care for HMO enrollees with chronic conditions and diseases. Several emerging organizational changes have the potential to change access to care for the vulnerable HMO enrollees. The shift in cost-cutting from fragmented clinical management of specific services at a point in time toward more integrated clinical management of all services for specific types of patients across time may improve access to care, as may increased efforts to attract and retain HMO enrollees. The increased importance of capitated provider organizations within the health system may restrict access in some ways, and expand access in others. CONCLUSIONS: Organizational changes can affect both access to care and its measurement. More research is needed on the effects of these changes on access to care and quality of care. For researchers examining access to care for vulnerable HMO enrollee populations, these changes create challenges to determine the most appropriate measures of access to care, and the most appropriate organizations and organizational characteristics to measure. RELEVANCE TO CLINICAL PRACTICE, MANAGEMENT, AND/OR POLICY: Changes in market competition are leading to organizational changes that affect access to care for vulnerable HMO enrollee populations. Public and/or private policies that improve measurement and reporting can affect market competition and improve access to care. PMID:9685111

Quantifying the effectiveness of conservation measures to control the spread of anthropogenic hybridization in stream salmonids: a climate adaptation case study

USGS Publications Warehouse

Al-Chokhachy, Robert K.; Muhlfeld, Clint C.; Boyer, Matthew; Jones, Leslie A.; Steed, Amber; Kershner, Jeffrey L.

2014-01-01

Quantifying the effectiveness of management actions to mitigate the effects of changing climatic conditions (i.e., climate adaptation) can be difficult, yet critical for conservation. We used population genetic data from 1984 to 2011 to assess the degree to which ambient climatic conditions and targeted suppression of sources of nonnative Rainbow Trout Oncorhynchus mykiss have influenced the spread of introgressive hybridization in native populations of Westslope Cutthroat Trout O. clarkii lewisi. We found rapid expansion in the spatial distribution and proportion of nonnative genetic admixture in hybridized populations from 1984 to 2004, but minimal change since 2004. The spread of hybridization was negatively correlated with the number of streamflow events in May that exceeded the 75th percentile of historic flows (r = −0.98) and positively correlated with August stream temperatures (r = 0.89). Concomitantly, suppression data showed a 60% decline in catch per unit effort for fish with a high proportion of Rainbow Trout admixture, rendering some uncertainty as to the relative strength of factors controlling the spread of hybridization. Our results illustrate the importance of initiating management actions to mitigate the potential effects of climate change, even where data describing the effectiveness of such actions are initially limited but the risks are severe.

When it rains, it pours: future climate extremes and health.

PubMed

Patz, Jonathan A; Grabow, Maggie L; Limaye, Vijay S

2014-01-01

The accelerating accumulation of greenhouse gases in the Earth's atmosphere is changing global environmental conditions in unprecedented and potentially irreversible ways. Climate change poses a host of challenges to the health of populations through complex direct and indirect mechanisms. The direct effects include an increased frequency of heat waves, rising sea levels that threaten low-lying communities, anticipated extremes in the global hydrologic cycle (droughts, floods, and intense storms), and adverse effects on agricultural production and fisheries due to environmental stressors and changes in land use. Indirectly, climate change is anticipated to threaten health by worsening urban air pollution and increasing rates of infectious (particularly waterborne and vector-borne) disease transmission. To provide a state-of-the-science review on the health consequences of a changing climate. Environmental public health researchers have concluded that, on balance, adverse health outcomes will dominate under these changed climatic conditions. The number of pathways through which climate change can affect the health of populations makes this environmental health threat one of the largest and most formidable of the new century. Geographic location plays an influential role the potential for adverse health effects caused by climate change, and certain regions and populations are more vulnerable than others to expected health effects. Two kinds of strategies are available for responding to climate change: mitigation policies (which aim to reduce greenhouse gas emissions) and adaptation measures (relating to preparedness for anticipated impacts). To better understand and address the complex nature of health risks posed by climate change, interdisciplinary collaboration is critical. Efforts to move beyond our current reliance on fossil fuels to cleaner, more sustainable energy sources may offer some of the greatest health opportunities in more than a century and cobenefits beyond the health sector. Because the nations least responsible for climate change are most vulnerable to its effects, the challenge to reduce greenhouse gas emissions is not merely technical, but also moral. Copyright © 2014 Icahn School of Medicine at Mount Sinai. Published by Elsevier Inc. All rights reserved.

Implications of climate change for northern Canada: freshwater, marine, and terrestrial ecosystems.

PubMed

Prowse, Terry D; Furgal, Chris; Wrona, Fred J; Reist, James D

2009-07-01

Climate variability and change is projected to have significant effects on the physical, chemical, and biological components of northern Canadian marine, terrestrial, and freshwater systems. As the climate continues to change, there will be consequences for biodiversity shifts and for the ranges and distribution of many species with resulting effects on availability, accessibility, and quality of resources upon which human populations rely. This will have implications for the protection and management of wildlife, fish, and fisheries resources; protected areas; and forests. The northward migration of species and the disruption and competition from invading species are already occurring and will continue to affect marine, terrestrial, and freshwater communities. Shifting environmental conditions will likely introduce new animal-transmitted diseases and redistribute some existing diseases, affecting key economic resources and some human populations. Stress on populations of iconic wildlife species, such as the polar bear, ringed seals, and whales, will continue as a result of changes in critical sea-ice habitat interactions. Where these stresses affect economically and culturally important species, they will have significant effects on people and regional economies. Further integrated, field-based monitoring and research programs, and the development of predictive models are required to allow for more detailed and comprehensive projections of change to be made, and to inform the development and implementation of appropriate adaptation, wildlife, and habitat conservation and protection strategies.

Conceptualising the interactive effects of climate change and biological invasions on subarctic freshwater fish.

PubMed

Rolls, Robert J; Hayden, Brian; Kahilainen, Kimmo K

2017-06-01

Climate change and species invasions represent key threats to global biodiversity. Subarctic freshwaters are sentinels for understanding both stressors because the effects of climate change are disproportionately strong at high latitudes and invasion of temperate species is prevalent. Here, we summarize the environmental effects of climate change and illustrate the ecological responses of freshwater fishes to these effects, spanning individual, population, community and ecosystem levels. Climate change is modifying hydrological cycles across atmospheric, terrestrial and aquatic components of subarctic ecosystems, causing increases in ambient water temperature and nutrient availability. These changes affect the individual behavior, habitat use, growth and metabolism, alter population spawning and recruitment dynamics, leading to changes in species abundance and distribution, modify food web structure, trophic interactions and energy flow within communities and change the sources, quantity and quality of energy and nutrients in ecosystems. Increases in temperature and its variability in aquatic environments underpin many ecological responses; however, altered hydrological regimes, increasing nutrient inputs and shortened ice cover are also important drivers of climate change effects and likely contribute to context-dependent responses. Species invasions are a complex aspect of the ecology of climate change because the phenomena of invasion are both an effect and a driver of the ecological consequences of climate change. Using subarctic freshwaters as an example, we illustrate how climate change can alter three distinct aspects of species invasions: (1) the vulnerability of ecosystems to be invaded, (2) the potential for species to spread and invade new habitats, and (3) the subsequent ecological effects of invaders. We identify three fundamental knowledge gaps focused on the need to determine (1) how environmental and landscape characteristics influence the ecological impact of climate change, (2) the separate and combined effects of climate and non-native invading species and (3) the underlying ecological processes or mechanisms responsible for changes in patterns of biodiversity.

Can Ingestion of Lead Shot and Poisons Change Population Trends of Three European Birds: Grey Partridge, Common Buzzard, and Red Kite?

PubMed Central

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 carrion. PMID:26799815

Can Ingestion of Lead Shot and Poisons Change Population Trends of Three European Birds: Grey Partridge, Common Buzzard, and Red Kite?

PubMed

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 carrion.

Projections of Water Stress Based on an Ensemble of Socioeconomic Growth and Climate Change Scenarios: A Case Study in Asia

PubMed Central

Fant, Charles; Schlosser, C. Adam; Gao, Xiang; Strzepek, Kenneth; Reilly, John

2016-01-01

The sustainability of future water resources is of paramount importance and is affected by many factors, including population, wealth and climate. Inherent in current methods to estimate these factors in the future is the uncertainty of their prediction. In this study, we integrate a large ensemble of scenarios—internally consistent across economics, emissions, climate, and population—to develop a risk portfolio of water stress over a large portion of Asia that includes China, India, and Mainland Southeast Asia in a future with unconstrained emissions. We isolate the effects of socioeconomic growth from the effects of climate change in order to identify the primary drivers of stress on water resources. We find that water needs related to socioeconomic changes, which are currently small, are likely to increase considerably in the future, often overshadowing the effect of climate change on levels of water stress. As a result, there is a high risk of severe water stress in densely populated watersheds by 2050, compared to recent history. There is strong evidence to suggest that, in the absence of autonomous adaptation or societal response, a much larger portion of the region’s population will live in water-stressed regions in the near future. Tools and studies such as these can effectively investigate large-scale system sensitivities and can be useful in engaging and informing decision makers. PMID:27028871

Response of an arctic predator guild to collapsing lemming cycles

PubMed Central

Schmidt, Niels M.; Ims, Rolf A.; Høye, Toke T.; Gilg, Olivier; Hansen, Lars H.; Hansen, Jannik; Lund, Magnus; Fuglei, Eva; Forchhammer, Mads C.; Sittler, Benoit

2012-01-01

Alpine and arctic lemming populations appear to be highly sensitive to climate change, and when faced with warmer and shorter winters, their well-known high-amplitude population cycles may collapse. Being keystone species in tundra ecosystems, changed lemming dynamics may convey significant knock-on effects on trophically linked species. Here, we analyse long-term (1988–2010), community-wide monitoring data from two sites in high-arctic Greenland and document how a collapse in collared lemming cyclicity affects the population dynamics of the predator guild. Dramatic changes were observed in two highly specialized lemming predators: snowy owl and stoat. Following the lemming cycle collapse, snowy owl fledgling production declined by 98 per cent, and there was indication of a severe population decline of stoats at one site. The less specialized long-tailed skua and the generalist arctic fox were more loosely coupled to the lemming dynamics. Still, the lemming collapse had noticeable effects on their reproductive performance. Predator responses differed somewhat between sites in all species and could arise from site-specific differences in lemming dynamics, intra-guild interactions or subsidies from other resources. Nevertheless, population extinctions and community restructuring of this arctic endemic predator guild are likely if the lemming dynamics are maintained at the current non-cyclic, low-density state. PMID:22977153

Response of an arctic predator guild to collapsing lemming cycles.

PubMed

Schmidt, Niels M; Ims, Rolf A; Høye, Toke T; Gilg, Olivier; Hansen, Lars H; Hansen, Jannik; Lund, Magnus; Fuglei, Eva; Forchhammer, Mads C; Sittler, Benoit

2012-11-07

Alpine and arctic lemming populations appear to be highly sensitive to climate change, and when faced with warmer and shorter winters, their well-known high-amplitude population cycles may collapse. Being keystone species in tundra ecosystems, changed lemming dynamics may convey significant knock-on effects on trophically linked species. Here, we analyse long-term (1988-2010), community-wide monitoring data from two sites in high-arctic Greenland and document how a collapse in collared lemming cyclicity affects the population dynamics of the predator guild. Dramatic changes were observed in two highly specialized lemming predators: snowy owl and stoat. Following the lemming cycle collapse, snowy owl fledgling production declined by 98 per cent, and there was indication of a severe population decline of stoats at one site. The less specialized long-tailed skua and the generalist arctic fox were more loosely coupled to the lemming dynamics. Still, the lemming collapse had noticeable effects on their reproductive performance. Predator responses differed somewhat between sites in all species and could arise from site-specific differences in lemming dynamics, intra-guild interactions or subsidies from other resources. Nevertheless, population extinctions and community restructuring of this arctic endemic predator guild are likely if the lemming dynamics are maintained at the current non-cyclic, low-density state.

[Land use pattern and its dynamic changes in Amur tiger distribution region].

PubMed

Li, Zhong-wen; Wu, Jian-guo; Kou, Xiao-jun; Tian, Yu; Wang, Tian-ming; Mu, Pu; Ge, Jian-ping

2009-03-01

Land use and land cover change has been the primary cause for the habitat loss and fragmentation in the distribution region of Amur tiger (Panthera tigris altaica). Based on the spatiotemporal changes of land use and land cover in the distribution region, as well as their effects on the population dynamics of Amur tiger, this paper analyzed the development process and its characteristics of the main land use types (agricultural land, forest land, and construction land) in this region, with the land use change history being divided chronically into three distinctive periods, i.e., ancient times (prior to 1860), modern times (1860-1949), and contemporary times (after 1949). The results showed that the sporadic land use in ancient times had no significant effects on the survival of Amur tiger, while the extensive and intensive land use after the 1860s was mainly responsible for the decrease of Amur tiger population and its living space. Since 1949, the Amur tiger distribution region has been divided into two parts, i.e., Northeast China and Russia Far East. The differences in land use pattern, policy, and intensity between these two parts led to different survival status of Amur tiger. The key driving forces for the land use change in Amur tiger distribution region were human population increase, policy change, and increased productivity.

How will predicted land-use change affect waterfowl spring stopover ecology? Inferences from an individual-based model

USGS Publications Warehouse

Beatty, William; Kesler, Dylan C.; Webb, Elisabeth B.; Naylor, Luke W.; Raedeke, Andrew H.; Humburg, Dale D.; Coluccy, John M.; Soulliere, Gregory J.

2017-01-01

Habitat loss, habitat fragmentation, overexploitation and climate change pose familiar and new challenges to conserving natural populations throughout the world. One approach conservation planners may use to evaluate the effects of these challenges on wildlife populations is scenario planning.We developed an individual-based model to evaluate the effects of future land use and land cover changes on spring-migrating dabbling ducks in North America. We assessed the effects of three Intergovernmental Panel on Climate Change emission scenarios (A1B, A2 and B1) on dabbling duck stopover duration, movement distances and mortality. We specifically focused on migration stopover duration because previous research has demonstrated that individuals arriving earlier on the nesting grounds exhibit increased reproductive fitness.Compared to present conditions, all three scenarios increased stopover duration and movement distances of agent ducks.Although all three scenarios presented migrating ducks with increased amounts of wetland habitat, scenarios also contained substantially less cropland, which decreased overall carrying capacity of the study area.Synthesis and applications. Land-use change may increase waterfowl spring migration stopover duration in the midcontinent region of North America due to reduced landscape energetic carrying capacity. Climate change will alter spatial patterns of crop distributions with corn and rice production areas shifting to different regions. Thus, conservation planners will have to address population-level energetic implications of shifting agricultural food resources and increased uncertainty in yearly precipitation patterns within the next 50 years.

Effects of climate change on polar bears.

PubMed

Wiig, Øystein; Aars, Jon; Born, Erik W

2008-01-01

In this article, we review the effects on polar bears of global warming that have already been observed, and try to evaluate what may happen to the polar bears in the future. Many researchers have predicted a wide range of impacts of climate change on polar bear demography and conditions. A predicted major reduction in sea ice habitat will reduce the availability of ice associated seals, the main prey of polar bears, and a loss and fragmentation of polar bear habitat will ultimately lead to large future reductions in most subpopulations. It is likely that polar bears will be lost from many areas where they are common today and also that the total population will change into a few more distinctly isolated populations.

The impact of aging physiology in critical care.

PubMed

Walker, Mandi; Spivak, Mark; Sebastian, Mary

2014-03-01

Aging physiology greatly impacts care delivery in the geriatric patient population. Consideration should be given to addressing the patient-specific needs regarding the systemic changes seen in the aging patient. Each major body system presents its own unique challenges to the critical care practitioner, and a comprehensive understanding of these changes is necessary to effectively care for this patient population. This article summarizes these changes and provides key points for the practitioner to consider when caring for the aging patient in the critical care arena. Copyright © 2014 Elsevier Inc. All rights reserved.

Cascading effects of thermally-induced anemone bleaching on associated anemonefish hormonal stress response and reproduction.

PubMed

Beldade, Ricardo; Blandin, Agathe; O'Donnell, Rory; Mills, Suzanne C

2017-10-10

Organisms can behaviorally, physiologically, and morphologically adjust to environmental variation via integrative hormonal mechanisms, ultimately allowing animals to cope with environmental change. The stress response to environmental and social changes commonly promotes survival at the expense of reproduction. However, despite climate change impacts on population declines and diversity loss, few studies have attributed hormonal stress responses, or their regulatory effects, to climate change in the wild. Here, we report hormonal and fitness responses of individual wild fish to a recent large-scale sea warming event that caused widespread bleaching on coral reefs. This 14-month monitoring study shows a strong correlation between anemone bleaching (zooxanthellae loss), anemonefish stress response, and reproductive hormones that decreased fecundity by 73%. These findings suggest that hormone stress responses play a crucial role in changes to population demography following climate change and plasticity in hormonal responsiveness may be a key mechanism enabling individual acclimation to climate change.Elevated temperatures can cause anemones to bleach, with unknown effects on their associated symbiotic fish. Here, Beldade and colleagues show that climate-induced bleaching alters anemonefish hormonal stress response, resulting in decreased reproductive hormones and severely impacted reproduction.

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

Treesearch

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

2013-01-01

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

Weather-Related Hazards and Population Change: A Study of Hurricanes and Tropical Storms in the United States, 1980–2012

PubMed Central

FUSSELL, ELIZABETH; CURRAN, SARA R.; DUNBAR, MATTHEW D.; BABB, MICHAEL A.; THOMPSON, LUANNE; MEIJER-IRONS, JACQUELINE

2017-01-01

Environmental determinists predict that people move away from places experiencing frequent weather hazards, yet some of these areas have rapidly growing populations. This analysis examines the relationship between weather events and population change in all U.S. counties that experienced hurricanes and tropical storms between 1980 and 2012. Our database allows for more generalizable conclusions by accounting for heterogeneity in current and past hurricane events and losses and past population trends. We find that hurricanes and tropical storms affect future population growth only in counties with growing, high-density populations, which are only 2 percent of all counties. In those counties, current year hurricane events and related losses suppress future population growth, although cumulative hurricane-related losses actually elevate population growth. Low-density counties and counties with stable or declining populations experience no effect of these weather events. Our analysis provides a methodologically informed explanation for contradictory findings in prior studies. PMID:29326480

Weather-Related Hazards and Population Change: A Study of Hurricanes and Tropical Storms in the United States, 1980-2012.

PubMed

Fussell, Elizabeth; Curran, Sara R; Dunbar, Matthew D; Babb, Michael A; Thompson, Luanne; Meijer-Irons, Jacqueline

2017-01-01

Environmental determinists predict that people move away from places experiencing frequent weather hazards, yet some of these areas have rapidly growing populations. This analysis examines the relationship between weather events and population change in all U.S. counties that experienced hurricanes and tropical storms between 1980 and 2012. Our database allows for more generalizable conclusions by accounting for heterogeneity in current and past hurricane events and losses and past population trends. We find that hurricanes and tropical storms affect future population growth only in counties with growing, high-density populations, which are only 2 percent of all counties. In those counties, current year hurricane events and related losses suppress future population growth, although cumulative hurricane-related losses actually elevate population growth. Low-density counties and counties with stable or declining populations experience no effect of these weather events. Our analysis provides a methodologically informed explanation for contradictory findings in prior studies.

A system dynamics feedback control model study of population of "India 2001" and policies for stabilizing growth.

PubMed

Patil, M K; Janahanlal, P S

1978-06-01

A mathematical population model is presented and diagrammed. The model is a nonlinear, higher order, self-regulating, goal-seeking system. In other words, the model treats the population system like a biological system which has positive and negative feedbacks. The model incorporates the effects of important economic factors that influence human birth and death rates. It calculates the total population size, which is a determinant of resource usage. It also indicates the demographic response, through a changing birth and death rate, to a changing resource supply. The model is illustrated with Indian population data, disaggregated by age into 15 levels each of which is, in turn, divided into 4 income levels. The effect on population growth of various alternative population policies is analyzed with the goal of stabilizing the population growth quickly without causing undue hardship. Different computer runs of the model are conducted, using different levels of family planning practice, different ages at marriage, and different distributions of income throughout the country. The policy which would result in the lowest population for the year 2001 is 1 in which family planning acceptance levels would increase from 15% in 1975 to 60% in 1980 and 100% from 1990 on. However, there is widespread opposition to this policy. It is felt that a much slower rise in family planning acceptance would be a more acceptable policy for stabilizing population in India.

Computer simulation models as tools for identifying research needs: A black duck population model

USGS Publications Warehouse

Ringelman, J.K.; Longcore, J.R.

1980-01-01

Existing data on the mortality and production rates of the black duck (Anas rubripes) were used to construct a WATFIV computer simulation model. The yearly cycle was divided into 8 phases: hunting, wintering, reproductive, molt, post-molt, and juvenile dispersal mortality, and production from original and renesting attempts. The program computes population changes for sex and age classes during each phase. After completion of a standard simulation run with all variable default values in effect, a sensitivity analysis was conducted by changing each of 50 input variables, 1 at a time, to assess the responsiveness of the model to changes in each variable. Thirteen variables resulted in a substantial change in population level. Adult mortality factors were important during hunting and wintering phases. All production and mortality associated with original nesting attempts were sensitive, as was juvenile dispersal mortality. By identifying those factors which invoke the greatest population change, and providing an indication of the accuracy required in estimating these factors, the model helps to identify those variables which would be most profitable topics for future research.

Effects of an invasive plant on population dynamics in toads.

PubMed

Greenberg, Daniel A; Green, David M

2013-10-01

When populations decline in response to unfavorable environmental change, the dynamics of their population growth shift. In populations that normally exhibit high levels of variation in recruitment and abundance, as do many amphibians, declines may be difficult to identify from natural fluctuations in abundance. However, the onset of declines may be evident from changes in population growth rate in sufficiently long time series of population data. With data from 23 years of study of a population of Fowler's toad (Anaxyrus [ = Bufo] fowleri) at Long Point, Ontario (1989-2011), we sought to identify such a shift in dynamics. We tested for trends in abundance to detect a change point in population dynamics and then tested among competing population models to identify associated intrinsic and extrinsic factors. The most informative models of population growth included terms for toad abundance and the extent of an invasive marsh plant, the common reed (Phragmites australis), throughout the toads' marshland breeding areas. Our results showed density-dependent growth in the toad population from 1989 through 2002. After 2002, however, we found progressive population decline in the toads associated with the spread of common reeds and consequent loss of toad breeding habitat. This resulted in reduced recruitment and population growth despite the lack of significant loss of adult habitat. Our results underscore the value of using long-term time series to identify shifts in population dynamics coincident with the advent of population decline. © 2013 Society for Conservation Biology.

Group selections among laboratory populations of Tribolium.

PubMed

Wade, M J

1976-12-01

Selection at the population level or group selection is defined as genetic change that is brought about or maintained by the differential extinction and/or proliferation of populations. Group selection for both increased and decreased adult population size was carried out among laboratory populations of Tribolium castaneum at 37-day intervals. The effect of individual selection within populations on adult population size was evaluated in an additional control series of populations. The response in the group selection treatments occurred rapidly, within three or four generations, and was large in magnitude, at times differing from the controls by over 200%. This response to selection at the populational level occurred despite strong individual selection which caused a decline in the mean size of the control populations from over 200 adults to near 50 adults in nine 37-day intervals. "Assay" experiments indicated that selective changes in fecundity, developmental time, body weight, and cannibalism rates were responsible in part for the observed treatment differences in adult population size. These findings have implications in terms of speciation in organisms whose range is composed of many partially isolated local populations.

Identifying and separating the effects of practice and of cognitive ageing during a large longitudinal study of elderly community residents.

PubMed

Rabbitt, P; Diggle, P; Smith, D; Holland, F; Mc Innes, L

2001-01-01

In protracted longitudinal studies of cognitive changes in old age volunteers must be repeatedly tested. Even with intervals of several years between assessment, this raises the possibility that improvements due to practice mask other changes. This problem is much more acute in brief studies of cognitive changes associated with progressive pathologies such as Alzheimer's disease or the effects of clinical interventions. Both types of study also encounter problems of selective dropout of frail and less able individuals leaving relatively 'elite' survivors. An analysis of data from repeated testing at 2-3 years intervals on the AH4 (1) intelligence test is presented to illustrate how a random effects model can be used to identify and disassociate age-related changes and practice effects at the population level, after effects of selective dropout and of background demographical variables have been taken into consideration. This analysis also provides some new, substantive empirical findings. Age-related changes are relatively slight between 49 and 70 years but much more marked between 70 and 80 years. Even with assessment points, several years apart the population average effect of practice is large relative to that of age-related change. Variation between individuals increases as samples age, providing the first clear evidence from a longitudinal study for marked individual differences in trajectories of cognitive ageing.

Evolved changes in the intracellular distribution and physiology of muscle mitochondria in high-altitude native deer mice.

PubMed

Mahalingam, Sajeni; McClelland, Grant B; Scott, Graham R

2017-07-15

Mitochondrial function changes over time at high altitudes, but the potential benefits of these changes for hypoxia resistance remains unclear. We used high-altitude-adapted populations of deer mice, which exhibit enhanced aerobic performance in hypoxia, to examine whether changes in mitochondrial physiology or intracellular distribution in the muscle contribute to hypoxia resistance. Permeabilized muscle fibres from the gastrocnemius muscle had higher respiratory capacities in high-altitude mice than in low-altitude mice. Highlanders also had higher mitochondrial volume densities, due entirely to an enriched abundance of subsarcolemmal mitochondria, such that more mitochondria were situated near the cell membrane and adjacent to capillaries. There were several effects of hypoxia acclimation on mitochondrial function, some of which were population specific, but they differed from the evolved changes in high-altitude natives, which probably provide a better indication of adaptive traits that improve performance and hypoxia resistance at high altitudes. High-altitude natives that have evolved to live in hypoxic environments provide a compelling system to understand how animals can overcome impairments in oxygen availability. We examined whether these include changes in mitochondrial physiology or intracellular distribution that contribute to hypoxia resistance in high-altitude deer mice (Peromyscus maniculatus). Mice from populations native to high and low altitudes were born and raised in captivity, and as adults were acclimated to normoxia or hypobaric hypoxia (equivalent to 4300 m elevation). We found that highlanders had higher respiratory capacities in the gastrocnemius (but not soleus) muscle than lowlanders (assessed using permeabilized fibres with single or multiple inputs to the electron transport system), due in large part to higher mitochondrial volume densities in the gastrocnemius. The latter was attributed to an increased abundance of subsarcolemmal (but not intermyofibrillar) mitochondria, such that more mitochondria were situated near the cell membrane and adjacent to capillaries. Hypoxia acclimation had no significant effect on these population differences, but it did increase mitochondrial cristae surface densities of mitochondria in both populations. Hypoxia acclimation also altered the physiology of isolated mitochondria by affecting respiratory capacities and cytochrome c oxidase activities in population-specific manners. Chronic hypoxia decreased the release of reactive oxygen species by isolated mitochondria in both populations. There were subtle differences in O 2 kinetics between populations, with highlanders exhibiting increased mitochondrial O 2 affinity or catalytic efficiency in some conditions. Our results suggest that evolved changes in mitochondrial physiology in high-altitude natives are distinct from the effects of hypoxia acclimation, and probably provide a better indication of adaptive traits that improve performance and hypoxia resistance at high altitudes. © 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.

Rainfall effects on rare annual plants

USGS Publications Warehouse

Levine, J.M.; McEachern, A.K.; Cowan, C.

2008-01-01

Variation in climate is predicted to increase over much of the planet this century. Forecasting species persistence with climate change thus requires understanding of how populations respond to climate variability, and the mechanisms underlying this response. Variable rainfall is well known to drive fluctuations in annual plant populations, yet the degree to which population response is driven by between-year variation in germination cueing, water limitation or competitive suppression is poorly understood.We used demographic monitoring and population models to examine how three seed banking, rare annual plants of the California Channel Islands respond to natural variation in precipitation and their competitive environments. Island plants are particularly threatened by climate change because their current ranges are unlikely to overlap regions that are climatically favourable in the future.Species showed 9 to 100-fold between-year variation in plant density over the 5–12 years of censusing, including a severe drought and a wet El Niño year. During the drought, population sizes were low for all species. However, even in non-drought years, population sizes and per capita growth rates showed considerable temporal variation, variation that was uncorrelated with total rainfall. These population fluctuations were instead correlated with the temperature after the first major storm event of the season, a germination cue for annual plants.Temporal variation in the density of the focal species was uncorrelated with the total vegetative cover in the surrounding community, suggesting that variation in competitive environments does not strongly determine population fluctuations. At the same time, the uncorrelated responses of the focal species and their competitors to environmental variation may favour persistence via the storage effect.Population growth rate analyses suggested differential endangerment of the focal annuals. Elasticity analyses and life table response experiments indicated that variation in germination has the same potential as the seeds produced per germinant to drive variation in population growth rates, but only the former was clearly related to rainfall.Synthesis. Our work suggests that future changes in the timing and temperatures associated with the first major rains, acting through germination, may more strongly affect population persistence than changes in season-long rainfall.

The Population Consequences of Disturbance Model Application to North Atlantic Right Whales (Eubalaena glacialis)

DTIC Science & Technology

2014-09-30

from individuals to the population by way of changes in either behavior or physiology, and the revised approach is called PCOD (Population...include modeling fecundity, and exploring the feasibility of incorporating acoustic disturbance and prey variability into the PCOD model...the applicability of the model to assessing the effects of acoustics on the population. We have refined and applied the PCOD model developed for

The effectiveness of mobile-health behaviour change interventions for cardiovascular disease self-management: A systematic review.

PubMed

Pfaeffli Dale, Leila; Dobson, Rosie; Whittaker, Robyn; Maddison, Ralph

2016-05-01

Mobile wireless devices (mHealth) have been used to deliver cardiovascular disease self-management interventions to educate and support patients in making healthy lifestyle changes. This systematic review aimed to determine the effectiveness of mHealth interventions on behavioural lifestyle changes and medication adherence for cardiovascular disease self-management. A comprehensive literature search was conducted from inception through to 3 March 2015 using MEDLINE, PubMed, PsycINFO, EMBASE and The Cochrane Library. Eligible studies used an experimental trial design to determine the effectiveness of an mHealth intervention to change lifestyle behaviours in any cardiovascular disease population. Data extracted included intervention and comparison group characteristics with a specific focus on the use of behaviour change techniques. Seven studies met our inclusion criteria and were included in the qualitative synthesis. All interventions were delivered in part by mobile phone text messaging. Three studies were effective at improving adherence to medication and two studies increased physical activity behaviour. No effects were observed on dietary behaviour or smoking cessation, measured in one study each. Simple text messaging interventions appeared to be most effective; however, no clear relationships were found between study findings and intervention dose, duration or behaviour change techniques targeted. Our review found mHealth has the potential to change lifestyle behaviour. Results are still limited to a small number of trials, inconsistent outcome measures and ineffective reporting of intervention characteristics. Large scale, longitudinal studies are now warranted to gain a clear understanding of the effects of mHealth on behaviour change in the cardiovascular disease population. © The European Society of Cardiology 2015.

Developing a model for effects of climate change on human health and health-environment interactions: Heat stress in Austin, Texas - Urban Climate

EPA Science Inventory

Human health and well-being are and will be affected by climate change, both directly through changes in extreme weather events and indirectly through weather-induced changes in human and natural systems. Populations are vulnerable to these changes in varying degrees, depending ...

Does rapid evolution matter? Measuring the rate of contemporary evolution and its impacts on ecological dynamics.

PubMed

Ellner, Stephen P; Geber, Monica A; Hairston, Nelson G

2011-06-01

Rapid contemporary evolution due to natural selection is common in the wild, but it remains uncertain whether its effects are an essential component of community and ecosystem structure and function. Previously we showed how to partition change in a population, community or ecosystem property into contributions from environmental and trait change, when trait change is entirely caused by evolution (Hairston et al. 2005). However, when substantial non-heritable trait change occurs (e.g. due to phenotypic plasticity or change in population structure) that approach can mis-estimate both contributions. Here, we demonstrate how to disentangle ecological impacts of evolution vs. non-heritable trait change by combining our previous approach with the Price Equation. This yields a three-way partitioning into effects of evolution, non-heritable phenotypic change and environment. We extend the approach to cases where ecological consequences of trait change are mediated through interspecific interactions. We analyse empirical examples involving fish, birds and zooplankton, finding that the proportional contribution of rapid evolution varies widely (even among different ecological properties affected by the same trait), and that rapid evolution can be important when it acts to oppose and mitigate phenotypic effects of environmental change. Paradoxically, rapid evolution may be most important when it is least evident. © 2011 Blackwell Publishing Ltd/CNRS.

Decline and recovery of a large carnivore: environmental change and long-term trends in an endangered brown bear population

PubMed Central

Naves, Javier; Fernández-Gil, Alberto

2016-01-01

Understanding what factors drive fluctuations in the abundance of endangered species is a difficult ecological problem but a major requirement to attain effective management and conservation success. The ecological traits of large mammals make this task even more complicated, calling for integrative approaches. We develop a framework combining individual-based modelling and statistical inference to assess alternative hypotheses on brown bear dynamics in the Cantabrian range (Iberian Peninsula). Models including the effect of environmental factors on mortality rates were able to reproduce three decades of variation in the number of females with cubs of the year (Fcoy), including the decline that put the population close to extinction in the mid-nineties, and the following increase in brown bear numbers. This external effect prevailed over density-dependent mechanisms (sexually selected infanticide and female reproductive suppression), with a major impact of climate driven changes in resource availability and a secondary role of changes in human pressure. Predicted changes in population structure revealed a nonlinear relationship between total abundance and the number of Fcoy, highlighting the risk of simple projections based on indirect abundance indices. This study demonstrates the advantages of integrative, mechanistic approaches and provides a widely applicable framework to improve our understanding of wildlife dynamics. PMID:27903871

Decline and recovery of a large carnivore: environmental change and long-term trends in an endangered brown bear population.

PubMed

Martínez Cano, Isabel; Taboada, Fernando González; Naves, Javier; Fernández-Gil, Alberto; Wiegand, Thorsten

2016-11-30

Understanding what factors drive fluctuations in the abundance of endangered species is a difficult ecological problem but a major requirement to attain effective management and conservation success. The ecological traits of large mammals make this task even more complicated, calling for integrative approaches. We develop a framework combining individual-based modelling and statistical inference to assess alternative hypotheses on brown bear dynamics in the Cantabrian range (Iberian Peninsula). Models including the effect of environmental factors on mortality rates were able to reproduce three decades of variation in the number of females with cubs of the year (Fcoy), including the decline that put the population close to extinction in the mid-nineties, and the following increase in brown bear numbers. This external effect prevailed over density-dependent mechanisms (sexually selected infanticide and female reproductive suppression), with a major impact of climate driven changes in resource availability and a secondary role of changes in human pressure. Predicted changes in population structure revealed a nonlinear relationship between total abundance and the number of Fcoy, highlighting the risk of simple projections based on indirect abundance indices. This study demonstrates the advantages of integrative, mechanistic approaches and provides a widely applicable framework to improve our understanding of wildlife dynamics. © 2016 The Author(s).

Forecasting the viability of sea turtle eggs in a warming world.

PubMed

Pike, David A

2014-01-01

Animals living in tropical regions may be at increased risk from climate change because current temperatures at these locations already approach critical physiological thresholds. Relatively small temperature increases could cause animals to exceed these thresholds more often, resulting in substantial fitness costs or even death. Oviparous species could be especially vulnerable because the maximum thermal tolerances of incubating embryos is often lower than adult counterparts, and in many species mothers abandon the eggs after oviposition, rendering them immobile and thus unable to avoid extreme temperatures. As a consequence, the effects of climate change might become evident earlier and be more devastating for hatchling production in the tropics. Loggerhead sea turtles (Caretta caretta) have the widest nesting range of any living reptile, spanning temperate to tropical latitudes in both hemispheres. Currently, loggerhead sea turtle populations in the tropics produce nearly 30% fewer hatchlings per nest than temperate populations. Strong correlations between empirical hatching success and habitat quality allowed global predictions of the spatiotemporal impacts of climate change on this fitness trait. Under climate change, many sea turtle populations nesting in tropical environments are predicted to experience severe reductions in hatchling production, whereas hatching success in many temperate populations could remain unchanged or even increase with rising temperatures. Some populations could show very complex responses to climate change, with higher relative hatchling production as temperatures begin to increase, followed by declines as critical physiological thresholds are exceeded more frequently. Predicting when, where, and how climate change could impact the reproductive output of local populations is crucial for anticipating how a warming world will influence population size, growth, and stability.

Alternative control of Aedes aegypti resistant to pyrethroids: lethal and sublethal effects of monoterpene bioinsecticides.

PubMed

Silva, Indira Ma; Martins, Gustavo F; Melo, Carlisson R; Santana, Alisson S; Faro, Ruan Rn; Blank, Arie F; Alves, Péricles B; Picanço, Marcelo C; Cristaldo, Paulo F; Araújo, Ana Paula A; Bacci, Leandro

2018-04-01

The mosquito Aedes aegypti is intensively controlled because it is a vector of viruses that cause numerous diseases, especially in tropical regions. As a consequence of the indiscriminate use of insecticides, populations from different regions have become resistant to pyrethroids. Here, we analyzed the lethal and sublethal effects of essential oil of Aristolochia trilobata and its major compounds on A. aegypti from susceptible and pyrethroid-resistant populations. Our results showed that the toxicity of the different compounds and behavioral changes in response to them are dependent on the stage of the insect life cycle. The monoterpene ρ-cymene caused high mortality in both larvae and adult females of A. aegypti, including those from the pyrethroid-resistant population. The monoterpenes limonene and linalool caused a sublethal effect in the larvae, triggering changes in the swimming pattern. This study highlights the potential of the essential oil of A. trilobata and its major compounds ρ-cymene and limonene for the control of A. aegypti and reveals the importance of analyzing sublethal effects on the population dynamics of the A. aegypti mosquito. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Fishing Quotas, Induced Allee Effect, and Fluctuation-Driven Extinction.

PubMed

Hastings, Harold M; Radin, Michael; Wiandt, Tamas

2017-01-01

We explore the potential of modifications to standard fishery models (for example Gordon-Schafer-Munro) to help understand events such as the collapse of the North Atlantic cod fishery. In particular we find that quota-driven and similar harvesting strategies induce an effective strong Allee effect (collapse if the population falls below a critical level). In the presence of environmental noise, fish population dynamics is similar to a random walk with (non-linear) drift. The expected survival time (first passage time to collapse) is shown to depend sensitively upon the amount of environmental noise and size of the 'safe zone' between the deterministic steady state population and the critical population level at which the system collapses; more precisely it is exponential in the cube of the size of the safe zone divided by the variance of the noise process. Similar scaling can be expected for more survival in more general systems with multiple steady states. Our calculations imply an amplification effect under which small increases in harvest yield large decreases in expected survival time, and one should be cautious in changes in harvesting, especially in fisheries with poor or limited data and fisheries affected by climate change.

Are the Liberal Arts an Endangered Species?

ERIC Educational Resources Information Center

Zammuto, Raymond F.

1984-01-01

Changes in the composition of colleges and universities during the 1970s and the changes in the subpopulation of institutions with a high commitment to liberal arts education were studied. The effect these changes had on the diversity of the population and subpopulation is described. (MLW)

Ice age fish in a warming world: minimal variation in thermal acclimation capacity among lake trout (Salvelinus namaycush) populations

PubMed Central

Kelly, Nicholas I.; Burness, Gary; McDermid, Jenni L.; Wilson, Chris C.

2014-01-01

In the face of climate change, the persistence of cold-adapted species will depend on their adaptive capacity for physiological traits within and among populations. The lake trout (Salvelinus namaycush) is a cold-adapted salmonid and a relict from the last ice age that is well suited as a model species for studying the predicted effects of climate change on coldwater fishes. We investigated the thermal acclimation capacity of upper temperature resistance and metabolism of lake trout from four populations across four acclimation temperatures. Individuals were reared from egg fertilization onward in a common environment and, at 2 years of age, were acclimated to 8, 11, 15 or 19°C. Although one population had a slightly higher maximal metabolic rate (MMR), higher metabolic scope for activity and faster metabolic recovery across all temperatures, there was no interpopulation variation for critical thermal maximum (CTM) or routine metabolic rate (RMR) or for the thermal acclimation capacity of CTM, RMR, MMR or metabolic scope. Across the four acclimation temperatures, there was a 3°C maximal increase in CTM and 3-fold increase in RMR for all populations. Above 15°C, a decline in MMR and increase in RMR resulted in sharply reduced metabolic scope for all populations acclimated at 19°C. Together, these data suggest there is limited variation among lake trout populations in thermal physiology or capacity for thermal acclimatization, and that climate change may impact lake trout populations in a similar manner across a wide geographical range. Understanding the effect of elevated temperatures on the thermal physiology of this economically and ecologically important cold-adapted species will help inform management and conservation strategies for the long-term sustainability of lake trout populations. PMID:27293646

Genetic Structure of Wild Bonobo Populations: Diversity of Mitochondrial DNA and Geographical Distribution

PubMed Central

Higuchi, Shoko; Sakamaki, Tetsuya; Hart, John A.; Hart, Terese B.; Tokuyama, Nahoko; Reinartz, Gay E.; Guislain, Patrick; Dupain, Jef; Cobden, Amy K.; Mulavwa, Mbangi N.; Yangozene, Kumugo; Darroze, Serge; Devos, Céline; Furuichi, Takeshi

2013-01-01

Bonobos (Pan paniscus) inhabit regions south of the Congo River including all areas between its southerly tributaries. To investigate the genetic diversity and evolutionary relationship among bonobo populations, we sequenced mitochondrial DNA from 376 fecal samples collected in seven study populations located within the eastern and western limits of the species’ range. In 136 effective samples from different individuals (range: 7–37 per population), we distinguished 54 haplotypes in six clades (A1, A2, B1, B2, C, D), which included a newly identified clade (D). MtDNA haplotypes were regionally clustered; 83 percent of haplotypes were locality-specific. The distribution of haplotypes across populations and the genetic diversity within populations thus showed highly geographical patterns. Using population distance measures, seven populations were categorized in three clusters: the east, central, and west cohorts. Although further elucidation of historical changes in the geological setting is required, the geographical patterns of genetic diversity seem to be shaped by paleoenvironmental changes during the Pleistocene. The present day riverine barriers appeared to have a weak effect on gene flow among populations, except for the Lomami River, which separates the TL2 population from the others. The central cohort preserves a high genetic diversity, and two unique clades of haplotypes were found in the Wamba/Iyondji populations in the central cohort and in the TL2 population in the eastern cohort respectively. This knowledge may contribute to the planning of bonobo conservation. PMID:23544084

Online Health Behavior and Disease Management Programs: Are We Ready for Them? Are They Ready for Us?

PubMed Central

Cummins, Carol O; Prochaska, James O; Prochaska, Janice M

2005-01-01

Advancing the science and practice of health promotion and disease management on the Internet requires a systematic program of research examining the population impact of such programs. With impact described as the combination of effectiveness and participation, such research needs to include the examination of the quality and effectiveness of programs that are available to the general public, as well as descriptive and predictive knowledge about population readiness to participate in such programs. There have been few studies examining the quality of interactive health behavior change (HBC) programs on the Internet, and even fewer investigations of the effectiveness of such programs. Based on the review of over 300 HBC programs on the Internet using the “5 A's” of Health Behavior Change on the Internet (HBC-I Screener), which represent standard minimum guidelines for evaluation, it appears HBC on the Internet is in the early stages of development. As health behavior change on the Internet matures from the provision of health information to meeting the requirements necessary to produce health behavior change, and as program developers take advantage of the interactive nature of the Internet, the basic screening and expanded evaluation criteria developed in this project will provide templates for both consumers and developers of programs. The second component necessary for evaluating the impact of HBC on the Internet is the extent to which the population is ready to participate in such programs. We need to move beyond a narrow focus on early adopters and produce a population perspective that includes those not ready, those getting ready, and those ready to use such programs, as well as those already participating. By understanding participation levels of such programs, and what drives this participation, the development and dissemination of practical tailored and targeted interventions can help maximize population participation in Internet programs for health behavior change. PMID:15998618

Hypotheses to explain the origin of species in Amazonia.

PubMed

Haffer, J

2008-11-01

The main hypotheses proposed to explain barrier formation separating populations and causing the differentiation of species in Amazonia during the course of geological history are based on different factors, as follow: (1) Changes in the distribution of land and sea or in the landscape due to tectonic movements or sea level fluctuations (Paleogeography hypothesis), (2) the barrier effect of Amazonian rivers (River hypothesis), (3) a combination of the barrier effect of broad rivers and vegetational changes in northern and southern Amazonia (River-refuge hypothesis), (4) the isolation of humid rainforest blocks near areas of surface relief in the periphery of Amazonia separated by dry forests, savannas and other intermediate vegetation types during dry climatic periods of the Tertiary and Quaternary (Refuge hypothesis), (5) changes in canopy-density due to climatic reversals (Canopy-density hypothesis) (6) the isolation and speciation of animal populations in small montane habitat pockets around Amazonia due to climatic fluctuations without major vegetational changes (Museum hypothesis), (7) competitive species interactions and local species isolations in peripheral regions of Amazonia due to invasion and counterinvasion during cold/warm periods of the Pleistocene (Disturbance-vicariance hypothesis) and (8) parapatric speciation across steep environmental gradients without separation of the respective populations (Gradient hypothesis). Several of these hypotheses probably are relevant to a different degree for the speciation processes in different faunal groups or during different geological periods. The basic paleogeography model refers mainly to faunal differentiation during the Tertiary and in combination with the Refuge hypothesis. Milankovitch cycles leading to global main hypotheses proposed to explain barrier formation separating populations and causing the differentiation of species in Amazonia during the course of geological history are based on different factors, as follow: (1) Changes in the distribution of land and sea or in the landscape due to tectonic movements or sea level fluctuations (Paleogeography hypothesis), (2) the barrier effect of Amazonian rivers (River hypothesis), (3) a combination of the barrier effect of broad rivers and vegetational changes in northern and southern Amazonia (River-refuge hypothesis), (4) the isolation of humid rainforest blocks near areas of surface relief in the periphery of Amazonia separated by dry forests, savannas and other intermediate vegetation types during dry climatic periods of the Tertiary and Quaternary (Refuge hypothesis), (5) changes in canopy-density due to climatic reversals (Canopy-density hypothesis) (6) the isolation and speciation of animal populations in small montane habitat pockets around Amazonia due to climatic fluctuations without major vegetational changes (Museum hypothesis), (7) competitive species interactions and local species isolations in peripheral regions of Amazonia due to invasion and counterinvasion during cold/warm periods of the Pleistocene (Disturbance-vicariance hypothesis) and (8) parapatric speciation across steep environmental gradients without separation of the respective populations (Gradient hypothesis). Several of these hypotheses probably are relevant to a different degree for the speciation processes in different faunal groups or during different geological periods. The basic paleogeography model refers mainly to faunal differentiation during the Tertiary and in combination with the Refuge hypothesis. Milankovitch cycles leading to global climatic-vegetational changes affected the biomes of the world not only during the Pleistocene but also during the Tertiary and earlier geological periods. New geoscientific evidence for the effect of dry climatic periods in Amazonia supports the predictions of the Refuge hypothesis. The disturbance-vicariance hypothesis refers to the presumed effect of cold/warm climatic phases of the Pleistocene only and is of limited general relevance because most extant species originated earlier and probably through paleogeographic changes and the formation of ecological refuges during the Tertiary.

The establishment and spread of myxomatosis and its effect on rabbit populations.

PubMed

Ross, J; Tittensor, A M

1986-12-15

The establishment of myxomatosis, the spread of the disease and its effects on rabbit populations in Australia and in Britain are briefly reviewed. Though the disease is endemic, with regular outbreaks in most rabbit populations, its effect is now much less dramatic than previously. Recent epidemiological studies have shown that the rate of spread of infection, the proportion of rabbits infected and the proportion dying from the disease are very much smaller than recorded in earlier outbreaks. The reasons for these changes are discussed, and the epidemiology of the disease in Britain is compared with that in Australia.

Directional selection effects on patterns of phenotypic (co)variation in wild populations

PubMed Central

Patton, J. L.; Hubbe, A.; Marroig, G.

2016-01-01

Phenotypic (co)variation is a prerequisite for evolutionary change, and understanding how (co)variation evolves is of crucial importance to the biological sciences. Theoretical models predict that under directional selection, phenotypic (co)variation should evolve in step with the underlying adaptive landscape, increasing the degree of correlation among co-selected traits as well as the amount of genetic variance in the direction of selection. Whether either of these outcomes occurs in natural populations is an open question and thus an important gap in evolutionary theory. Here, we documented changes in the phenotypic (co)variation structure in two separate natural populations in each of two chipmunk species (Tamias alpinus and T. speciosus) undergoing directional selection. In populations where selection was strongest (those of T. alpinus), we observed changes, at least for one population, in phenotypic (co)variation that matched theoretical expectations, namely an increase of both phenotypic integration and (co)variance in the direction of selection and a re-alignment of the major axis of variation with the selection gradient. PMID:27881744

Evolution in plant populations as a driver of ecological changes in arthropod communities

PubMed Central

Johnson, Marc T.J.; Vellend, Mark; Stinchcombe, John R.

2009-01-01

Heritable variation in traits can have wide-ranging impacts on species interactions, but the effects that ongoing evolution has on the temporal ecological dynamics of communities are not well understood. Here, we identify three conditions that, if experimentally satisfied, support the hypothesis that evolution by natural selection can drive ecological changes in communities. These conditions are: (i) a focal population exhibits genetic variation in a trait(s), (ii) there is measurable directional selection on the trait(s), and (iii) the trait(s) under selection affects variation in a community variable(s). When these conditions are met, we expect evolution by natural selection to cause ecological changes in the community. We tested these conditions in a field experiment examining the interactions between a native plant (Oenothera biennis) and its associated arthropod community (more than 90 spp.). Oenothera biennis exhibited genetic variation in several plant traits and there was directional selection on plant biomass, life-history strategy (annual versus biennial reproduction) and herbivore resistance. Genetically based variation in biomass and life-history strategy consistently affected the abundance of common arthropod species, total arthropod abundance and arthropod species richness. Using two modelling approaches, we show that evolution by natural selection in large O. biennis populations is predicted to cause changes in the abundance of individual arthropod species, increases in the total abundance of arthropods and a decline in the number of arthropod species. In small O. biennis populations, genetic drift is predicted to swamp out the effects of selection, making the evolution of plant populations unpredictable. In short, evolution by natural selection can play an important role in affecting the dynamics of communities, but these effects depend on several ecological factors. The framework presented here is general and can be applied to other systems to examine the community-level effects of ongoing evolution. PMID:19414473

Genomic signals of selection predict climate-driven population declines in a migratory bird.

PubMed

Bay, Rachael A; Harrigan, Ryan J; Underwood, Vinh Le; Gibbs, H Lisle; Smith, Thomas B; Ruegg, Kristen

2018-01-05

The ongoing loss of biodiversity caused by rapid climatic shifts requires accurate models for predicting species' responses. Despite evidence that evolutionary adaptation could mitigate climate change impacts, evolution is rarely integrated into predictive models. Integrating population genomics and environmental data, we identified genomic variation associated with climate across the breeding range of the migratory songbird, yellow warbler ( Setophaga petechia ). Populations requiring the greatest shifts in allele frequencies to keep pace with future climate change have experienced the largest population declines, suggesting that failure to adapt may have already negatively affected populations. Broadly, our study suggests that the integration of genomic adaptation can increase the accuracy of future species distribution models and ultimately guide more effective mitigation efforts. Copyright © 2018, American Association for the Advancement of Science.

Identification of a unique hepatocellular carcinoma line, Li-7, with CD13(+) cancer stem cells hierarchy and population change upon its differentiation during culture and effects of sorafenib.

PubMed

Yamada, Takeshi; Abei, Masato; Danjoh, Inaho; Shirota, Ryoko; Yamashita, Taro; Hyodo, Ichinosuke; Nakamura, Yukio

2015-04-11

Cancer stem cell (CSC) research has highlighted the necessity of developing drugs targeting CSCs. We investigated a hepatocellular carcinoma (HCC) cell line that not only has CSC hierarchy but also shows phenotypic changes (population changes) upon differentiation of CSC during culture and can be used for screening drugs targeting CSC. Based on a hypothesis that the CSC proportion should decrease upon its differentiation into progenitors (population change), we tested HCC cell lines (HuH-7, Li-7, PLC/PRF/5, HLF, HLE) before and after 2 months culture for several markers (CD13, EpCAM, CD133, CD44, CD90, CD24, CD166). Tumorigenicity was tested using nude mice. To evaluate the CSC hierarchy, we investigated reconstructivity, proliferation, ALDH activity, spheroid formation, chemosensitivity and microarray analysis of the cell populations sorted by FACS. Only Li-7 cells showed a population change during culture: the proportion of CD13 positive cells decreased, while that of CD166 positive cells increased. The high tumorigenicity of the Li-7 was lost after the population change. CD13(+)/CD166(-) cells showed slow growth and reconstructed the bulk Li-7 populations composed of CD13(+)/CD166(-), CD13(-)/CD166(-) and CD13(-)/CD166(+) fractions, whereas CD13(-)/CD166(+) cells showed rapid growth but could not reproduce any other population. CD13(+)/CD166(-) cells showed high ALDH activity, spheroid forming ability and resistance to 5-fluorouracil. Microarray analysis demonstrated higher expression of stemness-related genes in CD166(-) than CD166(+) fraction. These results indicated a hierarchy in Li-7 cells, in which CD13(+)/CD166(-) and CD13(-)/CD166(+) cells serve as slow growing CSCs and rapid growing progenitors, respectively. Sorafenib selectively targeted the CD166(-) fraction, including CD13(+) CSCs, which exhibited higher mRNA expression for FGF3 and FGF4, candidate biomarkers for sorafenib. 5-fluorouracil followed by sorafenib inhibited the growth of bulk Li-7 cells more effectively than the reverse sequence or either alone. We identified a unique HCC line, Li-7, which not only shows heterogeneity for a CD13(+) CSC hierarchy, but also undergoes a "population change" upon CSC differentiation. Sorafenib targeted the CSC in vitro, supporting the use of this model for screening drugs targeting the CSC. This type of "heterogeneous, unstable" cell line may prove more useful in the CSC era than conventional "homogeneous, stable" cell lines.

Mitigating Anthropocene influences in forests in the United States

Treesearch

Chadwick Dearing Oliver

2014-01-01

Anthropogenic and other climate changes, land use changes, forest structure changes, and introduced organisms are difficult to isolate with respect to their cumulative consequences. Similar changes have occurred before with undesirable effects and the currently high human population could suffer greatly if they happen again. Active forest management can help avoid...

Biodiversity Areas under Threat: Overlap of Climate Change and Population Pressures on the World’s Biodiversity Priorities

PubMed Central

Pricope, Narcisa G.; Husak, Gregory J.; Lopez-Carr, David

2017-01-01

Humans and the ecosystem services they depend on are threatened by climate change. Places with high or growing human population as well as increasing climate variability, have a reduced ability to provide ecosystem services just as the need for these services is most critical. A spiral of vulnerability and ecosystem degradation often ensues in such places. We apply different global conservation schemes as proxies to examine the spatial relation between wet season precipitation, population change over three decades, and natural resource conservation. We pose two research questions: 1) Where are biodiversity and ecosystem services vulnerable to the combined effects of climate change and population growth? 2) Where are human populations vulnerable to degraded ecosystem services? Results suggest that globally only about 20% of the area between 50 degrees latitude North and South has experienced significant change–largely wetting–in wet season precipitation. Approximately 40% of rangelands and 30% of rainfed agriculture lands have experienced significant precipitation changes, with important implications for food security. Over recent decades a number of critical conservation areas experienced high population growth concurrent with significant wetting or drying (e.g. the Horn of Africa, Himalaya, Western Ghats, and Sri Lanka), posing challenges not only for human adaptation but also to the protection and sustenance of biodiversity and ecosystem services. Identifying areas of climate and population risk and their overlap with conservation priorities can help to target activities and resources that promote biodiversity and ecosystem services while improving human well-being. PMID:28125659

Population demographic history of a temperate shrub, Rhododendron weyrichii (Ericaceae), on continental islands of Japan and South Korea.

PubMed

Yoichi, Watanabe; Tamaki, Ichiro; Sakaguchi, Shota; Song, Jong-Suk; Yamamoto, Shin-Ichi; Tomaru, Nobuhiro

2016-12-01

Continental islands provide opportunities for testing the effects of isolation and migration on genetic variation in plant populations. In characteristic of continental islands is that the geographic connections between these islands, which are currently distinguished by seaways, have experienced fluctuations caused by sea-level changes due to climate oscillations during the Quaternary. Plant populations on the islands have migrated between these islands via the exposed seafloors or been isolated. Here, we examined the demographic history of a temperate shrub, Rhododendron weyrichii , which is distributed in the southwestern parts of the Japanese archipelago and on an island of South Korea, using statistical phylogeographic approaches based on the DNA sequences of two chloroplast and eight nuclear loci in samples analyzed from 18 populations on eight continental islands, and palaeodistribution modeling. Time estimates for four island populations indicate that the durations of vicariance history are different between these populations, and these events have continued since the last glacial or may have predated the last glacial. The constancy or expansion of population sizes on the Japanese islands, and in contrast a bottleneck in population size on the Korean island Jeju, suggests that these islands may have provided different conditions for sustaining populations. The result of palaeodistribution modeling indicates that the longitudinal range of the species as a whole has not changed greatly since the last glacial maximum. These results indicate that exposed seafloors during the glacial period formed both effective and ineffective migration corridors. These findings may shed light on the effects of seafloor exposure on the migration of plants distributed across continental islands.

Assessing the impacts of climate change and socio-economic changes on flow and phosphorus flux in the Ganga river system.

PubMed

Jin, L; Whitehead, P G; Sarkar, S; Sinha, R; Futter, M N; Butterfield, D; Caesar, J; Crossman, J

2015-06-01

Anthropogenic climate change has impacted and will continue to impact the natural environment and people around the world. Increasing temperatures and altered rainfall patterns combined with socio-economic factors such as population changes, land use changes and water transfers will affect flows and nutrient fluxes in river systems. The Ganga river, one of the largest river systems in the world, supports approximately 10% global population and more than 700 cities. Changes in the Ganga river system are likely to have a significant impact on water availability, water quality, aquatic habitats and people. In order to investigate these potential changes on the flow and water quality of the Ganga river, a multi-branch version of INCA Phosphorus (INCA-P) model has been applied to the entire river system. The model is used to quantify the impacts from a changing climate, population growth, additional agricultural land, pollution control and water transfers for 2041-2060 and 2080-2099. The results provide valuable information about potential effects of different management strategies on catchment water quality.

Lake Diatoms as Indicators of Land Use Effects, Changing Environmental Conditions, and the Effectiveness of Management Practices

EPA Science Inventory

Lakes continue to face escalating pressures associated with land cover change and growing human populations. The U.S. EPA National Lakes Assessment, which sampled more than 1000 lakes in a probabilistic survey, was the first large scale effort to characterize the condition of lak...

Ecological dynamics across the Arctic associated with recent climate change

Treesearch

Eric Post; Mads C. Forchhammer; M. Syndonia Bret-Harte; Terry V. Callaghan; Torben R. Christensen; Bo Elberling; Anthony D. Fox; Olivier Gilg; David S. Hik; Toke T. Høye; Rolf A. Ims; Erik Jeppesen; David R. Klein; Jesper Madsen; A. David McGuire; Søren Rysgaard; Daniel E. Schindler; Ian Stirling; Mikkel P. Tamstorf; Nicholas J.C. Tyler; Rene van der Wal; Jeffrey Welker; Philip A. Wookey; Niels Martin Schmidt; Peter Aastrup

2009-01-01

At the close of the Fourth International Polar Year, we take stock of the ecological consequences of recent climate change in the Arctic, focusing on effects at population, community, and ecosystem scales. Despite the buffering effect of landscape heterogeneity, Arctic ecosystems and the trophic relationships that structure them have been severely perturbed. These...

Conversions of forest land: trends, determinants, projections, and policy considerations

Treesearch

Ralph Alig; Susan Stewart; David Wear; David Nowak

2010-01-01

Forest land conversion leads to ecological effects (e.g., changes in water quality and wildlife habitat) and socioeconomic effects (e.g., expanding urban-forest interface, reduced long-term timber production possibilities and loss of open space). Socioeconomic drivers of land use change such as population totals and personal income levels have increased substantially...

Effects of heat stress on working populations when facing climate change.

PubMed

Lundgren, Karin; Kuklane, Kalev; Gao, Chuansi; Holmér, Ingvar

2013-01-01

It is accepted that the earth's climate is changing in an accelerating pace, with already documented implications for human health and the environment. This literature review provides an overview of existing research findings about the effects of heat stress on the working population in relation to climate change. In the light of climate change adaptation, the purpose of the literature review was to explore recent and previous research into the impacts of heat stress on humans in an occupational setting. Heat stress in the workplace has been researched extensively in the past however, in the contemporary context of climate change, information is lacking on its extent and implications. The main factors found to exacerbate heat stress in the current and future workplace are the urban 'heat island effect', physical work, individual differences, and the developing country context where technological fixes are often not applicable. There is also a lack of information on the effects on vulnerable groups such as elderly people and pregnant women. As increasing temperatures reduce work productivity, world economic productivity could be condensed, affecting developing countries in the tropical climate zone disproportionately. Future research is needed taking an interdisciplinary approach, including social, economic, environmental and technical aspects.

Fishing-induced changes in adult length are mediated by skipped-spawning.

PubMed

Wang, Hui-Yu; Chen, Ying-Shiuan; Hsu, Chien-Chung; Shen, Sheng-Feng

2017-01-01

Elucidating fishing effects on fish population dynamics is a critical step toward sustainable fisheries management. Despite previous studies that have suggested age or size truncation in exploited fish populations, other aspects of fishing effects on population demography, e.g., via altering life histories and density, have received less attention. Here, we investigated the fishing effects altering adult demography via shifting reproductive trade-offs in the iconic, overexploited, Pacific bluefin tuna Thunnus orientalis. We found that, contrary to our expectation, mean lengths of catch increased over time in longline fisheries. On the other hand, mean catch lengths for purse seine fisheries did not show such increasing trends. We hypothesized that the size-dependent energetic cost of the spawning migration and elevated fishing mortality on the spawning grounds potentially drive size-dependent skipped spawning for adult tuna, mediating the observed changes in the catch lengths. Using eco-genetic individual-based modeling, we demonstrated that fishing-induced evolution of skipped spawning and size truncation interacted to shape the observed temporal changes in mean catch lengths for tuna. Skipped spawning of the small adults led to increased mean catch lengths for the longline fisheries, while truncation of small adults by the purse seines could offset such a pattern. Our results highlight the eco-evolutionary dynamics of fishing effects on population demography and caution against using demographic traits as a basis for fisheries management of the Pacific bluefin tuna as well as other migratory species. © 2016 by the Ecological Society of America.

Agricultural Management and Climatic Change Are the Major Drivers of Biodiversity Change in the UK

PubMed Central

Burns, Fiona; Eaton, Mark A.; Beckmann, Björn C.; Brereton, Tom; Brooks, David R.; Brown, Peter M. J.; Al Fulaij, Nida; Gent, Tony; Henderson, Ian; Noble, David G.; Parsons, Mark; Powney, Gary D.; Roy, Helen E.; Stroh, Peter; Walker, Kevin; Wilkinson, John W.; Wotton, Simon R.; Gregory, Richard D.

2016-01-01

Action to reduce anthropogenic impact on the environment and species within it will be most effective when targeted towards activities that have the greatest impact on biodiversity. To do this effectively we need to better understand the relative importance of different activities and how they drive changes in species’ populations. Here, we present a novel, flexible framework that reviews evidence for the relative importance of these drivers of change and uses it to explain recent alterations in species’ populations. We review drivers of change across four hundred species sampled from a broad range of taxonomic groups in the UK. We found that species’ population change (~1970–2012) has been most strongly impacted by intensive management of agricultural land and by climatic change. The impact of the former was primarily deleterious, whereas the impact of climatic change to date has been more mixed. Findings were similar across the three major taxonomic groups assessed (insects, vascular plants and vertebrates). In general, the way a habitat was managed had a greater impact than changes in its extent, which accords with the relatively small changes in the areas occupied by different habitats during our study period, compared to substantial changes in habitat management. Of the drivers classified as conservation measures, low-intensity management of agricultural land and habitat creation had the greatest impact. Our framework could be used to assess the relative importance of drivers at a range of scales to better inform our policy and management decisions. Furthermore, by scoring the quality of evidence, this framework helps us identify research gaps and needs. PMID:27007973

Acclimatization and Adaptive Capacity of Marine Species in a Changing Ocean.

PubMed

Foo, S A; Byrne, M

To persist in an ocean changing in temperature, pH and other stressors related to climate change, many marine species will likely need to acclimatize or adapt to avoid extinction. If marine populations possess adequate genetic variation in tolerance to climate change stressors, species might be able to adapt to environmental change. Marine climate change research is moving away from single life stage studies where individuals are directly placed into projected scenarios ('future shock' approach), to focus on the adaptive potential of populations in an ocean that will gradually change over coming decades. This review summarizes studies that consider the adaptive potential of marine invertebrates to climate change stressors and the methods that have been applied to this research, including quantitative genetics, laboratory selection studies and trans- and multigenerational experiments. Phenotypic plasticity is likely to contribute to population persistence providing time for genetic adaptation to occur. Transgenerational and epigenetic effects indicate that the environmental and physiological history of the parents can affect offspring performance. There is a need for long-term, multigenerational experiments to determine the influence of phenotypic plasticity, genetic variation and transgenerational effects on species' capacity to persist in a changing ocean. However, multigenerational studies are only practicable for short generation species. Consideration of multiple morphological and physiological traits, including changes in molecular processes (eg, DNA methylation) and long-term studies that facilitate acclimatization will be essential in making informed predictions of how the seascape and marine communities will be altered by climate change. © 2016 Elsevier Ltd. All rights reserved.

Long-term persistence, density dependence and effects of climate change on rosyside dace (Cyprinidae)

Treesearch

Gary D. Grossman; Gary Sundin; Robert E. Ratajczak

2016-01-01

SummaryWe used long-term population data for rosyside dace (Clinostomus funduloides), a numerically dominant member of a stochastically organised fish assemblage, to evaluate the relative importance of density-dependent and density-independent processes to population...

Environmental and Ecological Effects of Climate Change on Venomous Marine and Amphibious Species in the Wilderness.

PubMed

Needleman, Robert K; Neylan, Isabelle P; Erickson, Timothy B

2018-06-25

Recent analyses of data show a warming trend in global average air and sea surface ocean temperatures. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, the sea level has risen, and the concentrations of greenhouse gases have increased. This article will focus on climate change and projected effects on venomous marine and amphibious creatures with the potential impact on human health. Retrospective analysis of environmental, ecological, and medical literature with a focus on climate change, toxinology, and future modeling specific to venomous aquatic and amphibious creatures. Species included venomous jellyfish, poisonous fish, crown-of-thorns starfish, sea snakes, and toxic frogs. In several projected scenarios, rising temperatures, weather extremes, and shifts in seasons will increase poisonous population numbers, particularly with certain marine creatures like jellyfish and crown-of-thorns starfish. Habitat expansions by lionfish and sea snakes are projected to occur. These phenomena, along with increases in human populations and coastal development will likely increase human-animal encounters. Other species, particularly amphibious toxic frogs, are declining rapidly due to their sensitivity to any temperature change or subtle alterations in the stability of their environment. If temperatures continue to rise to record levels over the next decades, it is predicted that the populations of these once plentiful and critically important animals to the aquatic ecosystem will decline and their geographic distributions will shrink. Review of the literature investigating the effect and forecasts of climate change on venomous marine and amphibious creatures has demonstrated that temperature extremes and changes to climatic norms will likely have a dramatic effect on these toxicological organisms. The effects of climate change on these species through temperature alteration and rising coastal waters will influence each species differently and in turn potentially affect commercial industries, travel, tourism, and human health. Published by Elsevier Inc.

Forecasting consequences of changing sea ice availability for Pacific walruses

USGS Publications Warehouse

Udevitz, Mark S.; Jay, Chadwick V.; Taylor, Rebecca; Fischbach, Anthony S.; Beatty, William S.; Noren, Shawn R.

2017-01-01

The accelerating rate of anthropogenic alteration and disturbance of environments has increased the need for forecasting effects of environmental change on fish and wildlife populations. Models linking projections of environmental change with behavioral responses and bioenergetic effects can provide a basis for these forecasts. There is particular interest in forecasting effects of projected reductions in sea ice availability on Pacific walruses (Odobenus rosmarus divergens). Declining extent of summer sea ice in the Chukchi Sea has caused Pacific walruses to increase use of coastal haulouts and decrease use of more productive offshore feeding areas. Such climate-induced changes in distribution and behavior could ultimately affect the status of the population. We developed behavioral models to relate changes in sea ice availability to adult female walrus movements and activity levels, and adapted previously developed bioenergetics models to relate those activity levels to energy requirements and the ability to meet those requirements. We then linked these models to general circulation model projections of future ice availability to forecast autumn body condition for female walruses during mid- and late-century time periods. Our results suggest that as sea ice becomes less available in the Chukchi Sea, female walruses will spend more time in the southwestern region of that sea, less time resting, and less time foraging. Median forecasted autumn body masses were 7–12% lower in future scenarios than during recent times, but posterior distributions broadly overlapped and median forecasted seasonal mass losses (15–34%) were comparable to seasonal mass losses routinely experienced by other pinnipeds. These seasonal reductions in body condition would be unlikely to result in demographic effects, but if walruses were unable to rebuild endogenous reserves while wintering in the Bering Sea, cumulative effects could have implications for reproduction and survival, ultimately affecting the status of the Pacific walrus population. Our approach provides a general framework for forecasting consequences of the broad range of environmental changes and anthropogenic disturbances that may affect bioenergetics through behavioral responses or changes in prey availability.

Effects of temperature on transcriptome and cuticular hydrocarbon expression in ecologically differentiated populations of desert Drosophila.

PubMed

Etges, William J; de Oliveira, Cássia C; Rajpurohit, Subhash; Gibbs, Allen G

2017-01-01

We assessed the effects of temperature differences on gene expression using whole-transcriptome microarrays and cuticular hydrocarbon variation in populations of cactophilic Drosophila mojavensis . Four populations from Baja California and mainland Mexico and Arizona were each reared on two different host cacti, reared to sexual maturity on laboratory media, and adults were exposed for 12 hr to 15, 25, or 35°C. Temperature differences influenced the expression of 3,294 genes, while population differences and host plants affected >2,400 each in adult flies. Enriched, functionally related groups of genes whose expression changed at high temperatures included heat response genes, as well as genes affecting chromatin structure. Gene expression differences between mainland and peninsular populations included genes involved in metabolism of secondary compounds, mitochondrial activity, and tRNA synthases. Flies reared on the ancestral host plant, pitaya agria cactus, showed upregulation of genes involved in metabolism, while flies reared on organ pipe cactus had higher expression of DNA repair and chromatin remodeling genes. Population × environment (G × E) interactions had widespread effects on the transcriptome where population × temperature interactions affected the expression of >5,000 orthologs, and there were >4,000 orthologs that showed temperature × host plant interactions. Adults exposed to 35°C had lower amounts of most cuticular hydrocarbons than those exposed to 15 or 25°C, including abundant unsaturated alkadienes. For insects adapted to different host plants and climatic regimes, our results suggest that temperature shifts associated with climate change have large and significant effects on transcriptomes of genetically differentiated natural populations.

Predicting body temperature and activity of adult Polyommatus icarus using neural network models under current and projected climate scenarios.

PubMed

Howe, P D; Bryant, S R; Shreeve, T G

2007-10-01

We use field observations in two geographic regions within the British Isles and regression and neural network models to examine the relationship between microhabitat use, thoracic temperatures and activity in a widespread lycaenid butterfly, Polyommatus icarus. We also make predictions for future activity under climate change scenarios. Individuals from a univoltine northern population initiated flight with significantly lower thoracic temperatures than individuals from a bivoltine southern population. Activity is dependent on body temperature and neural network models of body temperature are better at predicting body temperature than generalized linear models. Neural network models of activity with a sole input of predicted body temperature (using weather and microclimate variables) are good predictors of observed activity and were better predictors than generalized linear models. By modelling activity under climate change scenarios for 2080 we predict differences in activity in relation to both regional differences of climate change and differing body temperature requirements for activity in different populations. Under average conditions for low-emission scenarios there will be little change in the activity of individuals from central-southern Britain and a reduction in northwest Scotland from 2003 activity levels. Under high-emission scenarios, flight-dependent activity in northwest Scotland will increase the greatest, despite smaller predicted increases in temperature and decreases in cloud cover. We suggest that neural network models are an effective way of predicting future activity in changing climates for microhabitat-specialist butterflies and that regional differences in the thermoregulatory response of populations will have profound effects on how they respond to climate change.

Nonlinear mixed effects modeling of the diurnal blood pressure profile in a multiracial population.

PubMed

van Rijn-Bikker, Petra C; Snelder, Nelleke; Ackaert, Oliver; van Hest, Reinier M; Ploeger, Bart A; van Montfrans, Gert A; Koopmans, Richard P; Mathôt, Ron A

2013-09-01

Cardiac and cerebrovascular events in hypertensive patients are related to specific features of the 24-hour diurnal blood pressure (BP) profile (i.e., daytime and nighttime BP, nocturnal dip (ND), and morning surge (MS)). This investigation aimed to characterize 24-hour diurnal systolic BP (SBP) with parameters that correlate directly with daytime and nighttime SBP, ND, and MS using nonlinear mixed effects modeling. Ambulatory 24-hour SBP measurements (ABPM) of 196 nontreated subjects from three ethnic groups were available. A population model was parameterized in NONMEM to estimate and evaluate the parameters baseline SBP (BSL), nadir (minimum SBP during the night), and change (SBP difference between day and night). Associations were tested between these parameters and patient-related factors to explain interindividual variability. The diurnal SBP profile was adequately described as the sum of 2 cosine functions. The following typical values (interindividual variability) were found: BSL = 139 mm Hg (11%); nadir = 122 mm Hg (14%); change = 25 mm Hg (52%), and residual error = 12 mm Hg. The model parameters correlate well with daytime and nighttime SBP, ND, and MS (R (2) = 0.50-0.92). During covariate analysis, ethnicity was found to be associated with change; change was 40% higher in white Dutch subjects and 26.8% higher in South Asians than in blacks. The developed population model allows simultaneous estimation of BSL, nadir, and change for all individuals in the investigated population, regardless of individual number of SBP measurements. Ethnicity was associated with change. The model provides a tool to evaluate and optimize the sampling frequency for 24-hour ABPM.

Heterosynaptic changes accompany long-term but not short-term potentiation of the perforant path in the anaesthetized rat.

PubMed

Abraham, W C; Bliss, T V; Goddard, G V

1985-06-01

Brief high-frequency trains of electrical stimulation delivered to the perforant path result in long-term potentiation (l.t.p.) of field potentials recorded extracellularly from granule cells of the dentate gyrus. L.t.p. of the population spike is often disproportionately greater than l.t.p. of the population excitatory post-synaptic potential (e.p.s.p.). We have investigated the basis of this effect in rats anaesthetized with sodium pentobarbitone. A series of graded stimuli were given before and after tetanization of the perforant path. From data obtained in this way, we plotted stimulus-response curves, and the relation (E-S curve) between the slope of the population e.p.s.p. (E) and the amplitude of the population spike (S). Curves relating spike onset latency to the slope of the e.p.s.p. were also constructed. Tetanization of the combined medial and lateral components of the perforant path led to long-term changes in the relation between the e.p.s.p. and the population spike. For a given e.p.s.p., the corresponding population spike was of greater amplitude and earlier onset. This E-S potentiation was marked by a shift to the left of the E-S amplitude curve and a downward displacement of the E-S latency curve. Tetanization of the lateral component of the perforant path had two long-term effects on responses evoked by test stimuli to the untetanized medial component: (1) long-term depression of the medial e.p.s.p. and (2) long-term E-S potentiation. The net result of these two heterosynaptically induced effects was to leave unaltered information transfer across medial perforant path-granule cell synapses; for a given test volley the e.p.s.p. was smaller, but because of E-S potentiation the population spike remained relatively unaffected. Short-term potentiation, which has a time course of only a few minutes and is presumed to be mediated by presynaptic mechanisms, was not accompanied by E-S potentiation or by corresponding changes in spike latency. Possible mechanisms of long-term heterosynaptic depression of the e.p.s.p. and of homo- and heterosynaptic E-S potentiation, are discussed. We conclude that although these effects probably reflect a generalized post-synaptic change, this change is unlikely to be a prolonged reduction in the membrane potential of granule cells.

The impacts of climate change on the abundance and distribution of the Spotted Wing Drosophila (Drosophila suzukii) in the United States and Canada

PubMed Central

Arteca, Ellen M.; Newman, Jonathan A.

2017-01-01

D. suzukii is a relatively recent and destructive pest species to the North American soft-skinned fruit industry. Understanding this species’ potential to shift in abundance and range due to changing climate is an important part of an effective mitigation and management strategy. We parameterized a temperature-driven D. suzukii population dynamics model using temperature data derived from several Global Circulation Models (CMIP5) with a range of relative concentration pathway (RCP) predictions. Mean consensus between the models suggest that without adaptation to both higher prolonged temperatures and higher short-term temperature events D. suzukii population levels are likely to drop in currently higher-risk regions. The potential drop in population is evident both as time progresses and as the severity of the RCP scenario increases. Some regions, particularly in northern latitudes, may experience increased populations due to milder winter and more developmentally-ideal summer conditions, but many of these regions are not currently known for soft-skinned fruit production and so the effects of this population increase may not have a significant impact. PMID:28396828

Surveillance and response for high-risk populations: what can malaria elimination programmes learn from the experience of HIV?

PubMed

Jacobson, Jerry O; Cueto, Carmen; Smith, Jennifer L; Hwang, Jimee; Gosling, Roly; Bennett, Adam

2017-01-18

To eliminate malaria, malaria programmes need to develop new strategies for surveillance and response appropriate for the changing epidemiology that accompanies transmission decline, in which transmission is increasingly driven by population subgroups whose behaviours place them at increased exposure. Conventional tools of malaria surveillance and response are likely not sufficient in many elimination settings for accessing high-risk population subgroups, such as mobile and migrant populations (MMPs), given their greater likelihood of asymptomatic infections, illegal risk behaviours, limited access to public health facilities, and high mobility including extended periods travelling away from home. More adaptive, targeted strategies are needed to monitor transmission and intervention coverage effectively in these groups. Much can be learned from HIV programmes' experience with "second generation surveillance", including how to rapidly adapt surveillance and response strategies to changing transmission patterns, biological and behavioural surveys that utilize targeted sampling methods for specific behavioural subgroups, and methods for population size estimation. This paper reviews the strategies employed effectively for HIV programmes and offers considerations and recommendations for adapting them to the malaria elimination context.

Convergence of body mass index of immigrants to the Canadian-born population: evidence from the National Population Health Survey (1994-2006).

PubMed

Setia, Maninder Singh; Quesnel-Vallee, Amelie; Abrahamowicz, Michal; Tousignant, Pierre; Lynch, John

2009-01-01

Recent immigrants typically have better physical health than the native born population. However, this 'healthy immigrant effect' tends to gradually wane over time, with increasing length of residence in the host country. To assess whether the body mass index (BMI) of different immigrant groups converged to the Canadian population's levels, we estimated 12-year trajectories of changes in BMI (accounting for socio-demographic changes). Using data from seven longitudinal waves of the National Population Health Survey (1994 through 2006), we compared the changes in BMI (kg/m(2)) among three groups: white immigrants, non-white immigrants and Canadian born, aged 18-54 at baseline. We applied linear random effects models to evaluate these BMI separately in 2,504 males and 2,960 females. BMI increased in Canadian born, white immigrants, and non-white immigrants over the 12-year period. However, non-white immigrants (males and females) had a lower mean BMI than Canadian born individuals during this period [Males: -2.27, 95% Confidence interval (CI) -3.02 to -1.53; Females: -1.84, 95% CI -2.79 to -0.90]. In contrast, the mean BMI in white male immigrants and Canadian born individuals were similar (-0.32, 95% CI -0.91 to 0.27). Even after adjusting for time since immigration, non-white immigrants had lower BMI than white immigrants. White male immigrants were the only sub-group to converge to the BMI of the Canadian born population. These results indicate that the loss of 'healthy immigrant effect' with regard to convergence of BMI to Canadian levels may not be experienced equally by all immigrants in Canada.

Livestock and elk grazing effects on stream morphology, brown trout population dynamics, movement, and growth rate, Valles Caldera National Preserve, New Mexico

Treesearch

Michael C. Anderson

2009-01-01

Ungulate grazing in riparian areas has been shown to detrimentally impact stream morphology and fish populations. Goals of this research were to assess changes in stream morphology and responses of a brown trout (Salmo trutta) population to exclusion of cattle (Bos taurus) and elk (Cervus elaphus) from riparian...

The effects of predator exclusion and food supplementation on Burrowing Owl (Speotyto cunicularia) population change in Saskatchewan

Treesearch

Troy I. Wellicome; Geoffrey L. Holroyd; Karyn Scalise; Earl R. Wiltse

1997-01-01

If low reproductive output plays an important role in the population decline of the Burrowing Owl (Speotyto cunicularia,) in Canada, we predicted the decline would slow or stop in our study population after consecutive years of productivity enhancement via food supplementation and predator exclusion. In the portion of our study site for which...

Effects of changing climate on aquatic habitat and connectivity for remnant populations of a wide-ranging frog species in an arid landscape.

PubMed

Pilliod, David S; Arkle, Robert S; Robertson, Jeanne M; Murphy, Melanie A; Funk, W Chris

2015-09-01

Amphibian species persisting in isolated streams and wetlands in desert environments can be susceptible to low connectivity, genetic isolation, and climate changes. We evaluated the past (1900-1930), recent (1981-2010), and future (2071-2100) climate suitability of the arid Great Basin (USA) for the Columbia spotted frog (Rana luteiventris) and assessed whether changes in surface water may affect connectivity for remaining populations. We developed a predictive model of current climate suitability and used it to predict the historic and future distribution of suitable climates. We then modeled changes in surface water availability at each time period. Finally, we quantified connectivity among existing populations on the basis of hydrology and correlated it with interpopulation genetic distance. We found that the area of the Great Basin with suitable climate conditions has declined by approximately 49% over the last century and will likely continue to decline under future climate scenarios. Climate conditions at currently occupied locations have been relatively stable over the last century, which may explain persistence at these sites. However, future climates at these currently occupied locations are predicted to become warmer throughout the year and drier during the frog's activity period (May - September). Fall and winter precipitation may increase, but as rain instead of snow. Earlier runoff and lower summer base flows may reduce connectivity between neighboring populations, which is already limited. Many of these changes could have negative effects on remaining populations over the next 50-80 years, but milder winters, longer growing seasons, and wetter falls might positively affect survival and dispersal. Collectively, however, seasonal shifts in temperature, precipitation, and stream flow patterns could reduce habitat suitability and connectivity for frogs and possibly other aquatic species inhabiting streams in this arid region.

Thermal acclimation modulates the impacts of temperature and enrichment on trophic interaction strengths and population dynamics.

PubMed

Sentis, Arnaud; Morisson, Julie; Boukal, David S

2015-09-01

Global change affects individual phenotypes and biotic interactions, which can have cascading effects up to the ecosystem level. However, the role of environmentally induced phenotypic plasticity in species interactions is poorly understood, leaving a substantial gap in our knowledge of the impacts of global change on ecosystems. Using a cladoceran-dragonfly system, we experimentally investigated the effects of thermal acclimation, acute temperature change and enrichment on predator functional response and metabolic rate. Using our experimental data, we next parameterized a population dynamics model to determine the consequences of these effects on trophic interaction strength and food-chain stability. We found that (1) predation and metabolic rates of the dragonfly larvae increase with acute warming, (2) warm-acclimated larvae have a higher maximum predation rate than cold-acclimated ones, and (3) long-term interaction strength increases with enrichment but decreases with both acclimation and acute temperatures. Overall, our experimental results show that thermal acclimation can buffer negative impacts of environmental change on predators and increase food-web stability and persistence. We conclude that the effect of acclimation and, more generally, phenotypic plasticity on trophic interactions should not be overlooked if we aim to understand the effects of climate change and enrichment on species interaction strength and food-web stability. © 2015 John Wiley & Sons Ltd.

Understanding Past Population Dynamics: Bayesian Coalescent-Based Modeling with Covariates

PubMed Central

Gill, Mandev S.; Lemey, Philippe; Bennett, Shannon N.; Biek, Roman; Suchard, Marc A.

2016-01-01

Effective population size characterizes the genetic variability in a population and is a parameter of paramount importance in population genetics and evolutionary biology. Kingman’s coalescent process enables inference of past population dynamics directly from molecular sequence data, and researchers have developed a number of flexible coalescent-based models for Bayesian nonparametric estimation of the effective population size as a function of time. Major goals of demographic reconstruction include identifying driving factors of effective population size, and understanding the association between the effective population size and such factors. Building upon Bayesian nonparametric coalescent-based approaches, we introduce a flexible framework that incorporates time-varying covariates that exploit Gaussian Markov random fields to achieve temporal smoothing of effective population size trajectories. To approximate the posterior distribution, we adapt efficient Markov chain Monte Carlo algorithms designed for highly structured Gaussian models. Incorporating covariates into the demographic inference framework enables the modeling of associations between the effective population size and covariates while accounting for uncertainty in population histories. Furthermore, it can lead to more precise estimates of population dynamics. We apply our model to four examples. We reconstruct the demographic history of raccoon rabies in North America and find a significant association with the spatiotemporal spread of the outbreak. Next, we examine the effective population size trajectory of the DENV-4 virus in Puerto Rico along with viral isolate count data and find similar cyclic patterns. We compare the population history of the HIV-1 CRF02_AG clade in Cameroon with HIV incidence and prevalence data and find that the effective population size is more reflective of incidence rate. Finally, we explore the hypothesis that the population dynamics of musk ox during the Late Quaternary period were related to climate change. [Coalescent; effective population size; Gaussian Markov random fields; phylodynamics; phylogenetics; population genetics. PMID:27368344

Wildlife population trends in protected areas predicted by national socio-economic metrics and body size

PubMed Central

Barnes, Megan D.; Craigie, Ian D.; Harrison, Luke B.; Geldmann, Jonas; Collen, Ben; Whitmee, Sarah; Balmford, Andrew; Burgess, Neil D.; Brooks, Thomas; Hockings, Marc; Woodley, Stephen

2016-01-01

Ensuring that protected areas (PAs) maintain the biodiversity within their boundaries is fundamental in achieving global conservation goals. Despite this objective, wildlife abundance changes in PAs are patchily documented and poorly understood. Here, we use linear mixed effect models to explore correlates of population change in 1,902 populations of birds and mammals from 447 PAs globally. On an average, we find PAs are maintaining populations of monitored birds and mammals within their boundaries. Wildlife population trends are more positive in PAs located in countries with higher development scores, and for larger-bodied species. These results suggest that active management can consistently overcome disadvantages of lower reproductive rates and more severe threats experienced by larger species of birds and mammals. The link between wildlife trends and national development shows that the social and economic conditions supporting PAs are critical for the successful maintenance of their wildlife populations. PMID:27582180

Wildlife population trends in protected areas predicted by national socio-economic metrics and body size

NASA Astrophysics Data System (ADS)

Barnes, Megan D.; Craigie, Ian D.; Harrison, Luke B.; Geldmann, Jonas; Collen, Ben; Whitmee, Sarah; Balmford, Andrew; Burgess, Neil D.; Brooks, Thomas; Hockings, Marc; Woodley, Stephen

2016-09-01

Ensuring that protected areas (PAs) maintain the biodiversity within their boundaries is fundamental in achieving global conservation goals. Despite this objective, wildlife abundance changes in PAs are patchily documented and poorly understood. Here, we use linear mixed effect models to explore correlates of population change in 1,902 populations of birds and mammals from 447 PAs globally. On an average, we find PAs are maintaining populations of monitored birds and mammals within their boundaries. Wildlife population trends are more positive in PAs located in countries with higher development scores, and for larger-bodied species. These results suggest that active management can consistently overcome disadvantages of lower reproductive rates and more severe threats experienced by larger species of birds and mammals. The link between wildlife trends and national development shows that the social and economic conditions supporting PAs are critical for the successful maintenance of their wildlife populations.

Editorial: 3rd Special Issue on behavior change, health, and health disparities.

PubMed

Higgins, Stephen T

2016-11-01

This Special Issue of Preventive Medicine (PM) is the 3rd that we have organized on behavior change, health, and health disparities. This is a topic of critical importance to improving U.S. population health. There is broad scientific consensus that personal behaviors such as cigarette smoking, other substance abuse, and physical inactivity/obesity are among the most important modifiable causes of chronic disease and its adverse impacts on population health. Hence, effectively promoting health-related behavior change needs to be a key component of health care research and policy. There is also broad recognition that while these problems extend throughout the population, they disproportionately impact economically disadvantaged populations and other vulnerable populations and represent a major contributor to health disparities. Thus, behavior change represents an essential step in curtailing health disparities, which receives special attention in this 3rd Special Issue. We also devote considerable space to the longstanding challenges of reducing cigarette smoking and use of other tobacco and nicotine delivery products in vulnerable populations, obesity, and for the first time food insecurity. Across each of these topics we include contributions from highly accomplished policymakers and scientists to acquaint readers with recent accomplishments as well as remaining knowledge gaps and challenges. Copyright © 2016 Elsevier Inc. All rights reserved.

Properties of the tick-borne encephalitis virus population during persistent infection of ixodid ticks and tick cell lines.

PubMed

Belova, Oxana A; Litov, Alexander G; Kholodilov, Ivan S; Kozlovskaya, Liubov I; Bell-Sakyi, Lesley; Romanova, Lidiya Iu; Karganova, Galina G

2017-10-01

Tick-borne encephalitis virus (TBEV) is the causative agent of tick-borne encephalitis (TBE), a vector-borne zoonotic neuroinfection. For successful circulation in natural foci the virus has to survive in the vector for a long period of time. Information about the effect of long-term infection of ticks on properties of the viral population is of great importance. In recent years, changes in the eco-epidemiology of TBEV due to changes in distribution of ixodid ticks have been observed. These changes in TBEV-endemic areas could result in a shift of the main tick vector species, which in turn may lead to changes in properties of the virus. In the present study we evaluated the selective pressure on the TBEV population during persistent infection of various species of ticks and tick cell lines. TBEV effectively replicated and formed persistent infection in ticks and tick cell lines of the vector species (Ixodes spp.), potential vectors (Dermacentor spp.) and non-vector ticks (Hyalomma spp.). During TBEV persistence in Ixodes and Dermacentor ticks, properties of the viral population remained virtually unchanged. In contrast, persistent TBEV infection of tick cell lines from both vector and non-vector ticks favoured selection of viral variants with low neuroinvasiveness for laboratory mice and substitutions in the E protein that increased local positive charge of the virion. Thus, selective pressure on viral population may differ in ticks and tick cell lines during persistent infection. Nevertheless, virus variants with properties of the original strain adapted to mouse CNS were not eliminated from the viral population during long-term persistence of TBEV in ticks and tick cell lines. Copyright © 2017 Elsevier GmbH. All rights reserved.

North American Brant: Effects of changes in habitat and climate on population dynamics

USGS Publications Warehouse

Ward, David H.; Reed, Austin; Sedinger, James S.; Black, Jeffrey M.; Derksen, Dirk V.; Castelli, Paul M.

2005-01-01

We describe the importance of key habitats used by four nesting populations of nearctic brant (Branta bernicla) and discuss the potential relationship between changes in these habitats and population dynamics of brant. Nearctic brant, in contrast to most geese, rely on marine habitats and native intertidal plants during the non-breeding season, particularly the seagrass, Zostera, and the macroalgae, Ulva. Atlantic and Eastern High Arctic brant have experienced the greatest degradation of their winter habitats (northeastern United States and Ireland, respectively) and have also shown the most plasticity in feeding behavior. Black and Western High Arctic brant of the Pacific Flyway are the most dependent on Zostera, and are undergoing a shift in winter distribution that is likely related to climate change and its associated effects on Zostera dynamics. Variation in breeding propensity of Black Brant associated with winter location and climate strongly suggests that food abundance on the wintering grounds directly affects reproductive performance in these geese. In summer, salt marshes, especially those containing Carex and Puccinellia, are key habitats for raising young, while lake shorelines with fine freshwater grasses and sedges are important for molting birds. Availability and abundance of salt marshes has a direct effect on growth and recruitment of goslings and ultimately, plays an important role in regulating size of local brant populations. ?? 2005 Blackwell Publishing Ltd.

Demographic consequences of age-structure in extreme environments: population models for arctic and alpine ptarmigan.

PubMed

Sandercock, Brett K; Martin, Kathy; Hannon, Susan J

2005-11-01

Organisms living in arctic and alpine environments are increasingly impacted by human activities. To evaluate the potential impacts of global change, a better understanding of the demography of organisms in extreme environments is needed. In this study, we compare the age-specific demography of willow ptarmigan (Lagopus lagopus) breeding at arctic and subalpine sites, and white-tailed ptarmigan (L. leucurus) breeding at an alpine site. Rates of egg production improved with age at the alpine and subalpine sites, but the stochastic effects of nest and brood predation led to similar rates of annual fecundity among 1-, 2-, and 3+-year-old females. All populations had short generation times (T<2.7 years) and low net reproductive rates (R0<1.2). Stable age distributions were weighted towards 1-year-old females in willow ptarmigan (>59%), and to 3+-year-old females in white-tailed ptarmigan (>47%). High damping ratios (rho>3.2) indicated that asymptotic estimates were likely to match natural age distributions. Sensitivity and elasticity values indicated that changes in juvenile survival would have the greatest impact on the finite rate of population change (lambda) in willow ptarmigan, whereas changes to the survival of 3+-year-old females would have a greater effect in white-tailed ptarmigan. High survivorship buffers white-tailed ptarmigan in alpine environments against the potential effects of climate change on annual fecundity, but may make the species more sensitive to the effects of pollutants or harvesting on adult survival. Conversely, processes that reduce annual fecundity would have a greater impact on the population viability of willow ptarmigan in arctic and subalpine environments. If these same demographic patterns prove to be widespread among organisms in extreme environments, it may be possible to develop general recommendations for conservation of the biological resources of arctic and alpine ecosystems.

Elk-effects vegetation monitoring program for Tomales Point Elk Range, Point Reyes National Seashore, California

USGS Publications Warehouse

McEachern, Kathryn; Semenoff-Irving, Marcia; van der Leeden, Pamela

2000-01-01

The monitoring program for elk effects on Tomales Point vegetation is designed to provide information on how tule elk grazing affects plant communities and rare species. The basic objective of the program is to show whether the elk are driving the vegetation into an unacceptable state by their grazing. The expectation is that as elk numbers increase, grazing pressure will increase too, resulting in unacceptable levels of any or all of the following: low vegetation ground cover, poor nutritional quality for the elk, undesirable increases in weedy species, unacceptable loss of native plant biodiversity, population declines in rare plants, population declines in plants used for food and nectar by the endangered silverspot butterfly, and increased erosion.The monitoring program has 3 basic components designed to provide complementary information on different aspects of the elk-vegetation system. Long-term plant community monitoring along permanent transects will show how plant species composition and cover are changing since cattle removal in 1979, and it will show whether any of he undesirable traits listed above are developing in the vegetation. However, monitoring these transects alone will not tell us what the effects of continued grazing by elk are apart from changes the vegetation would be undergoing anyway. In order to tease apart the elk effects from change that is happening because of cattle removal, elk exclosures are needed. By sampling inside and outside exclosures, we will be able to see how elk are modifying the rates and directions of change in the vegetation that would be happening in their absence. In a sense, the exclosures serve as a “check” on elk effects. They will allow us to interpret how much of the change is due to elk and how much can be attributed to other processes such as natural succession or weather patterns. This information will allow us to analyze whether changing elk management will have a desirable effect on the vegetation. Finally, periodic mapping and counting of plants in rare plant populations will show whether plant population ranges are expanding and populations are stable or growing. If not, then management actions can be taken to improve habitat conditions for the plants.A general summary of the rationale and sample design for each of the 3 components of the elk-effects monitoring program follows. Field sampling for the entire program should require about 15 weeks for a 2 to 3- person team, and data processing, analysis, and report writing should require about 9 weeks. Time and labor estimates for this program are given in Table A-1. In addition to elk-effects monitoring, Point Reyes staff periodically monitor fire transects and residual dry matter plots on Tomales Point. They are not included as part of the elk-effects monitoring program and they are described elsewhere. Protocols for fire and residual dry matter sampling are not included in the time estimate for the elk- effects monitoring program.