NSERC Postdoctoral Research Fellow

Research Interests:

My primary research interests focus on late Quaternary vegetation and climate change, with a focus on western North America. I am interested in the development and dynamics of plant communities and how climate, environment, and life history affect colonization, succession and species abundance through time. Since paleoecological methods provide a long-term perspective not afforded by most neoecological studies, I am interested in testing classic ecological questions using paleoecological tools such as pollen and plant macrofossil analysis. I am interested in integrating ecological studies across timescales and exploring ecological questions in the geological record. Can conclusions drawn from modern plant studies be applied to deep time plant communities?

As a Master’s student at the University of Ottawa, I conducted paleoecological research in the Kluane Lake region of the southwest Yukon, reconstructing late Quaternary vegetation dynamics and the associated paleoenvironmental history using pollen analysis, various lake sediment analysis techniques (e.g., magnetic susceptibility, loss-on-ignition), and radiocarbon dating of plant macrofossils.

As a Doctoral student at Simon Fraser University, I focussed on the late Quaternary paleoecology of the Pacific coast of Canada with field sites on Haida Gwaii (Queen Charlotte Islands), northern Vancouver Island, and the adjacent continental shelf. Pollen analysis, stomata analysis, fossil wood identification, and radiocarbon dating are the principle methods that I used. Emphasis was placed on the late Pleistocene and early Holocene periods, paying special attention to documenting evidence of the viability of the continental shelf as a human migration corridor, and the development of BC’s coastal temperate rainforest. Of particular significance were pollen and plant macrofossil analyses of terrestrial deposits from the continental shelf that were deposited at the end of the last glaciation. This research enhanced our understanding of forests and tundra that grew on the formerly-exposed continental shelf during the latest period of subaerial exposure.

My current research at the University of British Columbia continues to focus on the paleoecology of the Pacific coast of Canada. Postglacial changes in vegetation communities are most often attributed to past changes in climate. Differences in the life history of the plant species that compose vegetation communities are typically not considered when interpreting paleoecological records of plant communities. In this context, past fluctuations in climate are viewed as the cause of changes in vegetation communities. My current research in Dr. Mark Vellend’s lab seeks to evaluate these ideas by using paleoecological records of vegetation dynamics from coastal BC in concert with life history data and independent paleoclimate records. Are variations in paleoclimate sufficient to explain changes in the composition of these forests or do differences in life history offer alternative or complementary explanations? Regional scale climate change is likely the ultimate cause of vegetation change and the driving mechanism for species migration. However, given that climate change over the last 10,000 years has been minor compared to changes that occurred at the end of the last glaciation, other factors such as competition and differences in life history may have been more important in determining species abundances and vegetation dynamics in Holocene forests.

Selected Publications:

Wohlfarth, B., Tarasov, P., Bennike, O., Lacourse, T., Subetto, D., Torssander, P., and Romanenko, F. 2006. Lateglacial and Holocene palaeoenvironmental changes in the Rostov-Yaroslavl’ area, west central Russia. Journal of Paleolimnology 35: 543-569. (PDF)

Lacourse, T., and Mathewes, R.W. 2005. Terrestrial paleoecology of Haida Gwaii and continental shelf: vegetation, climate, and plant resources of the coastal migration route. In: D.W. Fedje and R.W. Mathewes (eds.), Haida Gwaii: Human History and Environment from the Time of Loon to the Time of the Iron People. University of British Columbia Press, Pacific Rim Series, Vancouver, pp. 38-58.

Lacourse, T., Mathewes, R.W., and Fedje, D.W. 2005. Late-glacial vegetation dynamics of the Queen Charlotte Islands and adjacent continental shelf, British Columbia, Canada. Palaeogeography, Palaeoclimatology, Palaeoecology 226: 36-57. (PDF)

Lacourse, T. 2005. Late Quaternary dynamics of forest vegetation on northern Vancouver Island, British Columbia, Canada. Quaternary Science Reviews 24: 105-121. (PDF)

Lacourse, T., Mathewes, R.W., and Fedje, D.W. 2003. Paleoecology of late-glacial terrestrial deposits with in situ conifers from the submerged continental shelf of western Canada. Quaternary Research 60: 180-188. (PDF)

Lacourse, T., and Gajewski, K. 2000. Late Quaternary vegetation history of Sulphur Lake, southwest Yukon Territory, Canada. Arctic 53: 27-35. (PDF)