Arctic LTER: Climate Change and Changing Disturbance Regimes in Arctic Landscapes

Printer-friendly version

The arctic region has warmed significantly over the past 30 years and arctic lands and freshwaters are already changing in response.  The changes include a general “greening” of the arctic landscape, changes in species distributions and abundance, and changes in geophysical and biogeochemical processes and cycles at local and regional scales.   Since 1975, the ARC LTER project and its predecessors have studied these changes by long-term monitoring of tundra and freshwater ecosystems in relation to climate changes, by experimental manipulations of whole tundra, lake, and stream ecosystems, and by comparisons among climatically different sites in northern Alaska and throughout the Arctic.  Increasingly, however, it is apparent that climatic warming in the Arctic is accompanied by dramatic changes in disturbance regime, including disturbances related to thawing of permafrost, a surprising increase in wildfire, and changes in the seasonality and synchrony of ecosystem processes.  These disturbances, in addition to having major impacts on biogeochemistry, populations, and communities, also lead to major changes in surface energy balance, surface temperatures, water balance, and heat transfer into the permafrost that lies beneath the tundra, lakes, and streams.  The result is much more dramatic and rapid change in communities and element cycles than is predicted in response to warming alone.  In the long term, warming-related changes in disturbance regime may be more important than the direct effects of warming on arctic tundra and freshwater ecosystems, and on the entire Arctic.  The ARC LTER project addresses these issues in an integrated landscape framework, viewing the Arctic landscape as a spatially linked system including tundra, streams, and lakes and leading to long-term predictions of change at hillslope, watershed, and regional scales.  Our long-term goal, to develop a predictive understanding of the landscape of Northern Alaska including tundra, streams, lakes, and their interactions, remains the same but during the current funding period (2011-2017) we maintain a particular emphasis on changing disturbance regimes and their interactions with climate change.