Evolutionary Species Responses to Global Environmental Changes

It is widely acknowledged that Earth's temperature will increase by about 3°C by 2100. Global warming is expected to significantly affect the biology and geographic distribution of species, as well as trigger species extinction and the disassembly of communities. This proposed research will use mathematical models to study the spatiotemporal dynamics of evolving populations when subjected to temporally changing environmental conditions. Models that forecast evolutionary and ecological responses are needed to provide reliable predictions of the effects of global environmental change on species. However, only a few studies have used mathematical models to predict evolutionary responses to temporally varying environments. The Intergovernmental Panel on Climate Change (2002) report identified assessment gaps that include the development of models for quantifying the impact of climate change on biodiversity. This report also indicated that models projecting changes in geographical distribution of species are incomplete. The proposed research will use spatial evolutionary models to determining when a temporally changing environment will cause (a) extinction, (b) adaptation, or (c) spatial redistribution of a species. These models will be able to address questions such as how adaptive evolution can prevent species extinction during rapid environmental change, and how ecological and genetic factors affect the magnitude of an evolutionary response. Within this context the following objectives are addressed. Objective 1: Determine the critical rate of evolution under a constantly moving environmental condition. This critical rate allows a population to persist by evolving to temporally changing local conditions. Objective 2: Determine the critical rate of species spatial shifts in a temporally changing environment gradient. This critical rate permits population persistence by spatial tracking of changing conditions. Objective 3: Determine the evolutionary responses of species in temporally changing environments. This objective examines the effects of a temporally changing environmental gradient on the distribution of a species when their populations can both adapt to new local conditions and move to optimum habitats. Characteristics of the environment and of the species may result in extinction, local adaptations to changing conditions, range shift, and range fragmentation. The theoretical framework used to meet the objectives will involve population dynamics and quantitative genetics theory. The models are described by ordinary and partial differential" equations and analyzed numerically. Results will provide a better understanding of species responses to global environmental changes and will facilitate the interpretation of experimental and field studies gathered on biological aspects of global warming. The proposal integrates several disciplines -ecology and evolution with a mathematical approach- that will enhance scientific understanding about the biological consequences of large-scale environmental changes such as global warming. Broader impacts of the proposed study stem from the direct societal importance of the topic, particularly for the conservation community. Also research training will be provided to undergraduates. Results of this research will be presented at meetings and in peerreviewed publications.