Lakes in the Anthropocene: Studying lake ecosystem changes across broad spatial and temporal scales

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One of the greatest challenges faced by ecologists and environmental scientists is the lack of reliable long-term observations. Yet, long-term perspectives (often pre-dating direct observational records) are often required for the study of ecological transitions and thresholds, and particularly during the human-impacted Anthropocene period. Fortunately, strategically selected lake and peat deposits often archive a robust record of past changes that can provide answers to many important questions. This proposal uses established, newly developed, and developing paleoenvironmental approaches to investigate different aspects of global environmental change. Theme 1 melds paleolimnology with the field of conservation biology through projects directed at seabird biovectors, and the use of paleolimnological records to track past changes in avian populations as well as their ecological repercussions (e.g. focussing of nutrients and contaminants into foodwebs). Conservation biologists rarely know the historical population sizes of extinct and threatened species, or how historical population fluctuations correspond to human influence versus climate change, and other environmental stressors. Working in close collaboration with some of Canada's leading ornithologists and focusing on colonies and species of national and international importance, we will study trajectories over time (on decadal to millennial scales) of avian inputs to a strategically selected suite of sites, which will allow us to assess these changes within the broader long-term environmental and climatic context. Questions posed include: How dynamic are bird colonies in space and time on the order of hundreds to thousands of years? Do seabirds move about the landscape as environmental changes occur in their terrestrial or marine habitat? What are the factors influencing these changes on long-time scales? Theme 2 expands our paleolimnological work in the Arctic to studies of the “Northern Great Lakes”. Although considerable progress has been made in understanding ecological transitions and threshold shifts in smaller Arctic lakes and ponds, similar research has lagged in large northern lakes such as Great Slave Lake and Great Bear Lake. We will address fundamental questions for these understudied Northern Great Lakes including: What are the baseline states of these lakes? How has recent warming and other anthropogenic stressors affected these lakes and how do these changes compare to changes reported in smaller lakes? Collectively, these projects will provide outstanding opportunities for the training of our next generation of ecologists and environmental scientists, addressing both fundamental and applied questions linked to conservation biology and aquatic ecology, while providing key information for policymakers and other stakeholders interested in using evidence-based management strategies.