Characterizing climate-resilient landscapes

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Prior to the arrival of humans to North America, relatively few species went extinct despite dramatic extremes of climate and environmental changes that occurred during hundreds of thousands of years of glacial and interglacial cycles. An important reason few plants and animals disappeared is that they may have been able to move into climate refugia. Climate refugia are hospitable areas that are resilient to changing environmental conditions over long periods of time. Resilient areas have continued to maintain plant and animal diversity for thousands of years and have the potential to do so into the future. This study uses the fossil pollen record of North America plant species to understand the factors that promoted the existence of climate refugia during glacial periods. This study will also examine how long these refugia lasted and how important they were for the survival of plants. Identifying regions that may be important for preserving species and understanding their importance during changing environmental conditions will inform conservation decisions. This project will train a postdoctoral researcher and provide research experiences for undergraduate students in the areas of paleoecology, landscape ecology, and conservation biology. The researchers will also include the public and conservation practitioners in presentations and activities that stress the role of resilience in the preservation of biodiversity.Resilience, a measure of the amount of disturbance that an ecosystem can undergo without switching states, is a fundamental ecological concept that determines species stability, community composition, and biogeographic changes over time. Several hypotheses exist concerning what climate and landscape determinants make a region more resilient to changing climatic conditions, including relatively low rates of 1) changing conditions and 2) climate velocity, and high 3) climate and 4) landscape diversity. However these hypothesized determinants of resilience lack support because relatively short ecological time periods are insufficient to identify areas that are climate resilient. An important strategy for identifying and understanding currently resilient areas is to test hypothesized determinants of resilience against areas that have been independently identified as resilient in the fossil record. To accomplish this, this project will test the determinants of resilience against two historical datasets: 1) the North American fossil pollen record for the last 10,000 years, which provides long-term record of change in plant community compositions, and 2) identified Pleistocene refugia. The use of the fossil record has the potential to transform our understanding of how landscape, climate, and ecosystem dynamics interact to create resilient areas and will potentially validate the mechanisms behind these causal hypotheses.