DOI: 10.5443/11396
title: PPS Arctic Canada (Present processes, Past changes, Spatio-temporal variability in the Arctic delimitation zone, Canada)

description: PPS Arctic Canada is a team of more than 170 researchers including 23 co-investigators, 3 post-doctoral fellows, 80 students from high school to graduate level and more than 70 northern residents and elders. Training and northern community involvement have been key components of our research project. Together with international researchers we developed common protocols and collected data during IPY to examine change at the tree line. Our multidisciplinary research team is developing methods for integrating data from a wide range of quantitative, qualitative and anecdotal data on change across tree line, or the Arctic delimitation zone. By actively interweaving research themes from ecological, environmental, and social sciences with northern cultural perspectives and community priorities, we are framing environmental change research in new ways, adopting new approaches to doing science in partnership with northerners, and developing new methods of cross-scale enquiry. We also integrate this research with northern priorities at specific sites to create opportunities for hands-on involvement by scientists from diverse disciplines, Elders, local knowledge holders, community people, youth and agents from multiple sectors. In the summers of 2007-09, we collected data at over a dozen locations in the Yukon, Northwest Territories, Nunavut, northern Manitoba, northern Québec and Labrador. Data were collected regarding the impacts of changes in climatic conditions on tree line and their consequences on ecosystems and communities. Other data were collected on trees of all ages, seeds, vegetation, snow and ice, microclimate, spatial pattern, soil and socioeconomic indicators across the forest tundra ecotone at sites across northern Canada. Our key finding continues to be the large amount of variability in tree growth, regeneration and spatial pattern among tree species, regions across Canada and even sites within the same region. Evidence of change in and movement of the forest-tundra ecotone is evident in some sites but not in others despite increasing temperatures. Seed viability or seedling recruitment may be hindering tree line movement at these sites. This variation in tree line response may be extremely challenging to outline general strategies for climate change adaptation in Arctic environments.
description: Purpose: PPS Arctic Canada (Present processes, Past changes, Spatio-temporal variability in the Arctic delimitation zone, Canada) is PPS Arctic's Canadian component, an International Polar Year-endorsed research program on the causes and consequences of change of the tree line. Recent research has noted latitudinal and altitudinal shifts in tree line that might be attributed to northern hemisphere warming. Predictions are that these changes will continue and that they can amplify warming at high latitudes. However, sparse empirical data on recent tree line dynamics has left considerable uncertainty as to the rate, magnitude and mechanisms of tree line responses to shifts in climate. Our research is ground-breaking because it begins with an expectation that there are important new relationships involving climate, environmental change, human health and well-being that we need to understand. The results from these studies contribute to our short-term objectives: 1) an analysis of recent change in tree and shrub distributions; 2) the collection of environmental and microclimate data to accompany tree line change; 3) an investigation of the mechanisms of vegetation change at tree line; 4) the mapping of the spatial pattern of tree and non-tree species at tree line and in tundra islands within the boreal forest to predict future changes as tree line migrates; 5) an assessment of the role of disturbance; and 6) the development of models of the long-term relationship between environmental change, resource availability and human health and well-being in the forest-tundra ecotone. We use methods familiar to natural and social science in order to understand change in the northern landscape as well as its meaning from ecological, social and cultural perspectives. This provides policy-relevant knowledge about environmental change and its human dimension in the tundra-taiga transition zone. Our long-term objectives are: 1) to model temporal and spatial tree line dynamics and to situate these processes within a comprehensive conceptual framework of environmental change that addresses ecological, social and cultural factors; 2) to assess the impact of climate change on processes within the tree line ecotone; 3) to determine ecosystem services of the tree line ecotone and their vulnerability with climate change and land use impacts; and 4) to develop conceptual models of the long term relationship of environmental change and human health and well-being in the Arctic and Sub-Arctic.
description: Summary: One of the most visible features in the Canadian Arctic is the delimitation zone or treeline. Although its position is related primarily to latitude and altitude, other factors like climate can play a role in its definition. By mapping the distribution of tree and non-tree species at the treeline, collecting climate and related environmental data, assessing the role of landscape disturbance and developing predictive models, this project is investigating how the Canadian treeline is changing and what mechanisms are creating this change. The relationship between the treeline and northern communities is also being investigated, as Northerners not only notice changes in the treeline over time, but are affected by these changes in terms of harvesting, traditional activities and eco-tourism.