نتایج جستجو برای: population change
تعداد نتایج: 1241284 فیلتر نتایج به سال:
BACKGROUND The increasing global prevalence of overweight and obesity has serious implications for the environment, as well as for health. We estimate the impact on greenhouse gas emissions of increases in the population distribution of body mass index (BMI). METHODS We estimated the food energy required to maintain basal metabolic rate in two hypothetical adult populations using the Schofiel...
Climate change is expected to alter the distribution and abundance of many species. Predictions of climate-induced population extinctions are supported by geographic range shifts that correspond to climatic warming, but few extinctions have been linked mechanistically to climate change. Here we show that extinctions of two populations of a checkerspot butterfly were hastened by increasing varia...
ing from heterogeneity in number of children: The average number of children by income quintile are reported in Table 6. However, the facts described in Section 2 also hold when conditioning on number of children (1, 2 or 3+).12 There are economies of scale in child care, i.e., a level effect, but the cross-sectional patterns hold for each type of family.13 Thus, this variation is not the main ...
Introduction Conclusions References
The environment is currently undergoing changes at both global (e.g., climate change) and local (e.g., tourism, pollution, habitat modification) scales that have the capacity to affect the viability of animal and plant populations. Many of these changes, such as human disturbance, have an anthropogenic origin and therefore may be mitigated by management action. To do so requires an understandin...
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 dynamics1–3. So far, however, little attention has been given to temporal changes in spatial synchrony—the coincident change in abundance or value across the landscape4—despite the importance of environm...
A computer simulation of North American end-Pleistocene human and large herbivore population dynamics correctly predicts the extinction or survival of 32 out of 41 prey species. Slow human population growth rates, random hunting, and low maximum hunting effort are assumed; additional parameters are based on published values. Predictions are close to observed values for overall extinction rates,...
Seabirds are facing a growing number of threats in both terrestrial and marine habitats, and many populations have experienced dramatic changes over past decades. Years of seabird research have improved our understanding of seabird populations and provided a broader understanding of marine ecological processes. In an effort to encourage future research and guide seabird conservation science, se...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید