Description

Tundra fires were once very rare on Alaska's North Slope, but are now becoming more frequent, probably as a result of climate change. Fire-management need to be highly adaptable during this time of rapid change; however, information concerning the patterns and processes of tundra fires on the North Slope is quite limited. Recent studies stress the drastic impacts tundra fires can have on carbon release, permafrost thaw, and plant succession. The current consensus is that the 'natural' fire regime, in which fires were rare, is now changing rapidly to a new regime characterized by hotter, larger, and more frequent fires. Understanding the fire ecology of Alaskan tundra is important for several reasons including: 1) the region contains petroleum infrastructure of national importance, 2) Native residents rely on subsistence resources like caribou and waterfowl whose populations are affected by the fire regime, and 3) permafrost (perennially frozen ground) stores enormous amounts of organic carbon (C) that can be released to the atmosphere when fires combust the vegetation and peat now protecting it from thaw. Complex fire-management challenges are posed by these divergent concerns. Here we propose an interdisciplinary study by scientists and land managers aimed at providing fire managers in Alaska with a comprehensive overview of tundra fire ecology in the Arctic and specifically on Alaska's North Slope based on a synthesis of previous research as well as new data. This project directly addresses JFSP Task C1. Implications of Changing Ecosystems. We assess the details of future fire regimes by reconstructing the sensitivity of fire regimes to past warming events and testing how they impacted permafrost thaw and carbon. This project is also highly relevant to Task C5. Post-Fire Landscape Management; in particular, how vegetation, fuels, and post-fire successional pathways may change as tundra ecosystems adjust to new fire regimes. This study addresses four key, knowledge gaps that now exist in our understanding of fire ecology on the North Slope. These gaps include climatic effects on fire frequency; impacts of burning on the release of organic C stored in permafrost; spatial patterning of burning in terms of fire size, frequency, and severity; and impacts of fire size and severity on post-fire successional pathways. Our methods include reconstructions of how fire frequency and the release of permafrost C responded to climate changes in the past. We will also use remote sensing and ground truthing to map the contemporary mosaic of burning and quantify fire effects on vegetation cover and on permafrost thaw. This research builds directly on ongoing studies by our team of investigators, and proposed field costs are extensively shared between their organizations. This project will culminate in a joint land-manager/scientist workshop co-organized with the Alaskan Fire Science Consortium. The goal of this workshop is to spur and assist development of fire-management plans that are effective and adaptable to shifting tundra fire regimes during a time of rapid climate change.