Lake sediment records of artic ecosystem responses to holocene climatic changes

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Canada's natural environment is presently undergoing rapid change. Global warming and losses of biodiversity threaten the ecosystems that Canadians depend upon for economic prosperity, health and agriculture. Therefore, there is a need for a better understanding of the mechanisms through which ecosystems respond to climatic change. In order to gain this understanding, it is necessary to study ecosystems on long temporal and large spatial scales. Paleoclimatic records indicate that since the last ice age, significant climatic changes have occurred. The goal of the research program is to use the long-term perspective given by paleoecological science to quantify the responses of biological systems to climatic changes on long time scales; the findings supply case studies of these responses, and will aid in predicting the impacts of global warming and losses of biological diversity. Paleoecological science involves the study of lake or wetland sediment cores that contain detailed records of environmental change over thousands of years. The major technique used here is the analysis of the microscopic biological remains preserved in the sediments, including pollen grains and aquatic organisms such as diatoms. These indicators show how terrestrial vegetation and aquatic communities have changed over time and these records can be superimposed on paleoclimatic data to quantify the correlations between climatic and ecological changes. The research program will be focussed on Arctic Canada as this region is highly sensitive to climatic change. Field work will concentrate on sampling across gradients of biodiversity and biological productivity to determine how the properties of ecosystems modulate responses to climatic change. This strategy will enable the identification of the most sensitive types of Arctic ecosystems, and will also show how losses of biodiversity might exacerbate the impacts of climatic change.