DOI: 10.5443/11401
title: Climate change Impacts on Canadian Arctic Tundra ecosystems (CICAT): Interdisciplinary and multi-scale assessments

description: At some CICAT research sites, we established experiments that simulate warming and changes in snow depth and measured the responses. Warming causes earlier flowering, greater growth and an increase in the cover of shrubs and grasses. We also examined the changes in vegetation across large areas using satellite data, and our results have shown a decrease in important winter range of the Bathurst caribou herd during the past twenty years due mainly to increases in fires. We have also made the first coordinated measurements of the amounts of carbon dioxide absorbed by tundra plants and given off by plants and soils over a variety of tundra ecosystems. We have found they all absorb more carbon dioxide than they emit during the growing season. We also found that polar desert soils are surprisingly important sources of methane, a potent greenhouse gas. How tundra vegetation and processes such as carbon dioxide fluxes respond to warming will depend on the responses of soil microorganisms, such as bacteria and fungi. These organisms control the release and availability of nutrients in the soil and hence affect the ability of plants to respond to warming. We are studying these organisms and how they are likely to respond to climate change. We are using much of our information in ecosystem models linked to CiCAT, which provide predictions of how these tundra systems are likely to change over the coming decades. The preliminary modelling indicates that tundra ecosystems will continue to absorb more carbon than they release, although there will be variation between years and between tundra types. Interviews with elders in communities have provided invaluable information on how tundra ecosystems have changed over the past decades and help direct the scientific research. School classes are also involved in monitoring vegetation change near communities, and students are learning how traditional ecological knowledge and science can be used together. Bringing together scientific knowledge with traditional/local knowledge, allows a better understanding of changes that have occurred across the landscape and prepare the Métis of the North Slave and other Aboriginal organizations for expected changes due to climate change.
description: Purpose: Canada has the greatest variety of tundra ecosystems of all polar nations. Tundra ecosystems are very important in the global carbon balance as they cover nearly 30% of the country and contain 10-20% of the soil carbon on the planet. They provide essential services to northern communities, especially northern aboriginal communities which depend on wildlife resources. The climate of the North has warmed faster than at any time in the past with rates of 1°C/decade in the past 30 years. Changes in Arctic tundra ecosystems are occurring and they match responses in warming experiments. However, our knowledge of the current state of tundra ecosystems in Canada is remarkably poor, which makes it difficult to predict how these systems will behave as the climate changes. Our International Polar Year (IPY) research program, Climate Impacts on Canadian Arctic Tundra Ecosystems: Interdisciplinary and Multi-scale Assessments (CiCAT), provides the unique opportunity for Canadian and international researchers to conduct the first comprehensive assessment of tundra ecosystems across the Canadian Arctic and their potential for change in response to climate variability and change. Our research involves studies from molecules to satellites, including plot-level studies of vegetation and soils from the tree line to the high Arctic. The following themes have been addressed through this project: 1. Tundra Vegetation - This theme has several sub-projects: a. Response to Experimental and Observed Changes b. Vegetation Mapping and Change Detection c. Classification of Arctic Vegetation d. Shorebird Habitat Survey e. Historical Vegetation Change in Tundra and Peatlands f. Common Plant Fungi and Plant-Herbivore Dynamics g. Community-based Assessment of Vegetation Change 2. Carbon and nitrogen cycling in tundra soils 3. Carbon flux between the land and atmosphere 4. Métis knowledge of climate change and vegetation impacts 5. Ecological integrity monitoring in Arctic National Parks 6. Ecosystem modelling to predict exchanges of greenhouse gases The major focus within CiCAT involves both scientific and local traditional knowledge approaches. Projects deal with various spatial and temporal scales and with the combination of experiments and long-term observations.
description: Summary: Canada has the greatest variety of tundra ecosystems of all polar nations, yet little is known about these ecosystems. Ranging from the tree line to the High Arctic, this project is undertaking the first comprehensive assessment of the Canadian tundra. Results from this work will feed into the development of models to predict future change of the tundra. To maximize the effectiveness of these models, data have been collected at various scales, from plot-level to remote sensing, and on various tundra features such as vegetation, soils, microorganisms, carbon dioxide exchange, wildlife and northern communities. Experimental work has been undertaken simulating warming to determine how tundra ecosystems will react to changes in climate.