2000. Response of subarctic vegetation to transient climatic change on the Seward Peninsula in north-west Alaska

• Main Authors: T. Scott Rupp, F. Stuart Chapin Iii, Anthony M. Starfield
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: boreal forest; climatic change; landscape dynamics; spatially explicit; transient dynamics; treeline; Seward Peninsula; Subarctic; Tundra; Alaska
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.420.4363; http://www.lter.uaf.edu/pdf/669_rupp_chapin_2000.pdf

Understanding the response of terrestrial ecosystems to climatic warming is a challenge because of the complex interactions of climate, disturbance, and recruitment across the landscape. We use a spatially explicit model (ALFRESCO) to simulate the transient response of subarctic vegetation to climatic warming on the Seward Peninsula (80 000 km 2) in north-west Alaska. Model calibration efforts showed that ®re ignition was less sensitive than ®re spread to regional climate (temperature and precipitation). In the model simulations a warming climate led to slightly more ®res and much larger ®res and expansion of forest into previously treeless tundra. Vegetation and ®re regime continued to change for centuries after cessation of the simulated climate warming. Flammability increased rapidly in direct response to climate warming and more gradually in response to climate-induced vegetation change. In the simulations warming caused as much as a 228 % increase in the total area burned per decade, leading to an increasingly early successional and more homogenous deciduous forestdominated landscape. A single transient 40-y drought led to the development of a novel grassland±steppe ecosystem that persisted inde®nitely and caused permanent increases in ®res in both the grassland and adjacent vegetation. These simulated changes in vegetation and disturbance dynamics under a warming climate have important implications for regional carbon budgets and biotic feedbacks to regional climate.