|Chapin Iii, F. Stuart|
|Mcguire, A. David|
|Mulholland, P. J.|
|Peters, Debra - Deb|
|Roby, D. D.|
Submitted to: Government Publication/Report
Publication Type: Government Publication
Publication Acceptance Date: 6/15/2008
Publication Date: 1/5/2009
Citation: Fagre, D.B., Charles, C.W., Allen, C.D., Birkeland, C., Chapin III, F., Groffman, P.M., Guntenspergen, G.R., Knapp, A.K., McGuire, A., Mulholland, P., Peters, D.C., Roby, D., Sugihara, G. 2009. Climate change science program. Thresholds of change in ecosystems. U.S. Geological Survey, Reston, VA, Synthesis and Assessment Product 4.2, 156 pp. Interpretive Summary: Thresholds of ecological change (i.e., nonlinear changes in ecosystem response to incremental changes in drivers such as temperature and precipitation) are not well understood, but may be critical to our ability to develop adaptation strategies for managing natural resources in a rapidly changing world. Directional changes in climate, in particular increases in temperature, may provide additional opportunities for the development of threshold dynamics that must be understood before predictions of future ecosystem dynamics can be made. In this synthesis, we first define thresholds based on historical and current perspectives. We then provide a series of case studies to illustrate the importance of thresholds in a variety of systems. Finally, we provide strategies for dealing with systems undergoing threshold changes.
Technical Abstract: In the past three decades, climate change has become a pronounced driver of ecosystem change. Changes in phenology, range shift of species, and increases in disturbances such as wildfires have all reflected ecosystem scales responses to a warming biosphere. There have also been abrupt, nonlinear changes in ecosystems where the level of response to incremental increases in temperature have suddenly changed trajectories. These thresholds of ecosystem change are not well understood but are potentially critical to adaptation strategies for managing natural resources in a rapidly changing world. This synthesis is intended to evaluate the current state of understanding of thresholds and to recommend possible actions to improve knowledge and adjust management priorities even with incomplete understanding of what drives thresholds of change and when they will occur.