Our lab works at the interface between plant ecology and global change research.  Much of our research focuses on understanding the biological and climatic drivers that promote shrub expansion into alpine tundra and the ecosystem consequences of the invasion of shrub populations upslope or northward beyond their current range limit.

Research Questions

One of our primary research areas explores how shrubs are changing in tundra ecosystems.

1. Are shrubs increasing in tundra ecosystems?

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There is growing evidence for increasing shrubs in many tundra ecosystems. Increased shrubs could be due to a warming climate and improved growing conditions or a variety of other factors.

2. Are shrubs advancing up slopes in alpine areas and moving northward into the Arctic?

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We use historical data sets such as repeat photography to explore vegetation change in tundra ecosystems. We are interested in research questions such as whether shrub species have the potential to form dominant canopies at the northern range edge or whether growth forms are locally adapted.

3. Is increased shrub growth related to climate warming in tundra ecosystems?

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We work with collaborators working at sites around the Arctic.  This is a map of some of the field sites from members of the Shrub Hub. Patterns of shrub increase could vary across gradients in tundra ecosystems.

4. How will increased shrubs modify the tundra plant community, carbon stores and nutrient cycling?

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Shrubs can influence the reflectivity (albedo) of tundra ecosystems which could feedback to influence climate warming. We investigate the feedbacks among shrub increases, ecosystem functions and climate. In winter, shrubs can trap snow.  In summer, shrubs can shade soils. These processes could feedback to influence nutrient cycling, carbon stores and biodiversity.

Research Sites

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In the Kluane Region of the Southwest Yukon, we are exploring changes in the shrubline ecotone. Much of our field research takes place in the Yukon Territory of Northern Canada. At the Herschel Island site on the Arctic Coast of the Yukon Territory, we are exploring vegetation-permafrost interactions.


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Much of our research is field-based experimental or observational ecology. This is a common garden experiment established in 2013 to test for local adaptation in growth form in tundra willows across climate and latitudinal gradients. We use dendroecology to work back in time and understand how shrub growth has changed over the previous decades and to estimate the climate sensitivity of shrub growth. We also conduct collaborative research, use large scale data sets and statistical modelling to explore patterns of change at the tundra biome scale.