The potential for geographic range shifts of species is a pressing issue in ecology given the rapid rate of anthropogenic climate change. The shifts will change total species richness and biodiversity patterns because species likely differ in their capacity to shift under climate change. This concern has sparked efforts to project changes in species' geographic distributions. Several of the underlying assumptions of the ecological theories driving these projections, however, have not been rigorously tested. Current models of species' ranges assume uniformity with respect to climatic impacts on fitness for all individuals of a species, which ignores local selection and historical genetic differences. Following this, these models assume that warmer temperature at the poleward edge of a species' range will increase fitness ('peripheral enhancement'), causing population increases and greater poleward colonization. My dissertation examines this assumption by using two butterfly species, Erynnis propertius and Papillo zelicaon, that co-occur and have contrasting levels of host specialization and dispersal ability. The aim of my research is to determine if populations are uniform or differentiated with respect to their responses to both temperature and host plant. I used a series of common garden experiments in the field and lab where I variede climate and host plant to see if locally adapted forms within species are present. I did not find evidence of local adaption in P. zelicaon, but populations across the species' range performed poorly temperature altered growth and survivorship in this species. Growth and survivorship of E. propertius larvae increased in warmer conditions. However, local adaptation during the overwintering period counteracted the increases found during the growing period. Further, southern population of E. propertius are locally adapted to their natal host plants, so colonization poleward may be further limited. This more nuanced consideration of species could lead to different expectations for the biological consequences of climate change if species can not shift their ranges as previously projected. We can not properly mitigate the effects of climate change on biodiversity until our projection methods capture realistic dynamics of species' ranges.

There is currently widespread concern about the impact of continuing climate change on the distribution, and ultimately persistence of species across all the major taxa. While much previous work has focussed on using climate envelope models to make projections of the location of potential future suitable climate space for a variety of species, these can at best give an indication of the likely direction and potential magnitude of distributional change. They lack information on spatial population dynamics, dispersal, habitat suitability, local adaptation and inter-specific interactions. The aim of this thesis was to explore how some of these other factors might alter projections regarding species' distributional change in response to climate change, using both theoretical models, and garden warbler (Sylvia borin) as a model system. A key aspect which has been largely over-looked until very recently is the complex range dynamics which can result from spatial variation in population dynamics, and the impacts of inter-annual variability rather than simply mean climate, both of which can impact extinction risk. Much insight into future impacts of climate change can also be gained through studies of past distributional changes, such as that observed in the British breeding population of garden warbler in the last three decades. In many cases, studies at smaller-scales are necessary to elucidate the mechanisms of climate change impacts and further explore potential synergies with other drivers of ecosystem change such as habitat loss and species invasions. The particular combination of factors which should be included to make projections of distributional change will be species-specific and scale-dependent, therefore modelling exercises should be carefully designed depending on the intended outcome for conservation.

Wildlife Responses to Climate Change is the culmination of a three-year project to research and study the impacts of global climate change on ecosystems and individual wildlife species in North America. In 1997, the National Wildlife Federation provided fellowships to eight outstanding graduate students to conduct research on global climate change, and engaged leading climate change experts Stephen H. Schneider and Terry L. Root to advise and guide the project. This book presents the results, with chapters describing groundbreaking original research by some of the brightest young scientists in America. The book presents case studies that examine: ways in which local and regional climate variables affect butterfly populations and habitat ranges how variations in ocean temperatures have affected intertidal marine species the potential effect of reduced snow cover on plants in the Rocky Mountains the potential effects of climate change on the distribution of vegetation in the United States how climate change may increase the susceptibility of ecosystems to invasions of non-native species the potential for environmental change to alter interactions between a variety of organisms in whitebark pine communities of the Greater Yellowstone Ecosystem Also included are two introductory chapters by Schneider and Root that discuss the rationale behind the project and offer an overview of climate change and its implications for wildlife. Each of the eight case studies provides important information about how biotic systems respond to climatic variables, and how a changing climate may affect biotic systems in the future. They also acknowledge the inherent complexities of problems likely to arise from changes in climate, and demonstrate the types of scientific questions that need to be explored in order to improve our understanding of how climate change and other human disturbances affect wildlife and ecosystems. Wildlife Responses to Climate Change is an important addition to the body of knowledge critical to scientists, resource managers, and policymakers in understanding and shaping solutions to problems caused by climate change. It provides a useful resource for students and scientists studying the effects of climate change on wildlife and will assist resource managers and other wildlife professionals to better understand factors affecting the species they are striving to conserve.

Propagule, evolution.

This open access book describes the serious threat of invasive species to native ecosystems. Invasive species have caused and will continue to cause enormous ecological and economic damage with ever increasing world trade. This multi-disciplinary book, written by over 100 national experts, presents the latest research on a wide range of natural science and social science fields that explore the ecology, impacts, and practical tools for management of invasive species. It covers species of all taxonomic groups from insects and pathogens, to plants, vertebrates, and aquatic organisms that impact a diversity of habitats in forests, rangelands and grasslands of the United States. It is well-illustrated, provides summaries of the most important invasive species and issues impacting all regions of the country, and includes a comprehensive primary reference list for each topic. This scientific synthesis provides the cultural, economic, scientific and social context for addressing environmental challenges posed by invasive species and will be a valuable resource for scholars, policy makers, natural resource managers and practitioners.

This book focuses on how climate affects or affected the biosphere and vice versa both in the present and in the past. The chapters describe how ecosystems from the Antarctic and Arctic, and from other latitudes, respond to global climate change. The papers highlight plant responses to atmospheric CO2 increase, to global warming and to increased ultraviolet-B radiation as a result of stratospheric ozone depletion.