Late quaternary paleoecology and paleoclimatology of the Pacific Coast of Canada

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To better understand future climate change and its potential impacts on British Columbia's forests, our research examines evidence deposited in lake sediments over thousands of years to study how natural variability in climate affected plant communities in the past. The main objectives of our research are: 1) to understand the development of vegetation communities on the Pacific coast of Canada since the last ice age; 2) to determine how climate has changed during that time; and, 3) to understand the role of factors other than climate (e.g., ecological differences in tree species such as shade tolerance) in how and why vegetation communities change on long-time scales. We collect cores of sediment from lakes along the coast of British Columbia and identify plant remains such as pollen and seeds that were deposited in those lakes in the past and are preserved in their sediments today. This allows us to determine how the composition of surrounding plant communities has changed since deposition of the lake sediments. We also analyze other fossils such as insect remains as well as the physical properties of the lake sediments to identify past environmental changes, including changes in climate, hydrological regimes and erosion rates. By combining data from several lakes, we can identify regional patterns in past climate change, including the rates and magnitudes of those changes, and use these to understand how forests have responded to past changes in climate. For example, previous research found that warmer and drier summers between about 7000 and 10,000 years ago changed the geographic distribution of many plant species, and that forest fires were more common than today. By understanding past environmental changes like these, we can predict and thus better prepare for the impacts of future climate change. This research has many important social and economic implications for Canadian society, ranging from providing relevant knowledge for management and conservation of our forests and other ecosystems today, to providing archaeologists and First Nations peoples with reconstructions of the ecological and environmental context that human populations experienced in the past.