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Consequences of Novel Disturbance Regimes on Climate-Induced Biogeographic Shifts along the Appalachian Trail

Funded By: Department of Energy, National Institute of Climatic Change Research, $ 125,000

Northward biogeographical shifts are expected in the Eastern US with more southerly species (e.g., oak, hickory, pine) replacing northern hardwoods (e.g., maple, beech, birch).  The Appalachian Trail (AT) MEGA-Transect, an ecological monitoring program along this vector, provides an exceptional opportunity to test scientific hypotheses of disturbance-vegetation-climate interactions between southeast and northeast regions.  Fire is an extensive disturbance agent in the southeastern US but has a disputed historical role in the northeast.

In this project, we hypothesize that under future climate, fire risk may be enhanced, resulting in positive feedbacks and sustaining northward migration of fire-prone vegetation.  Alternatively, in the absence of these fire-climate conditions, niche-based projections of northerly migration of fire-prone habitat may be overestimated.  This research will clarify how climate-induced shifts in species may interact with or produce novel disturbance regimes. 

To explore this, we are developing a multi-scaled modeling approach that links a biogeographical model (MC1) with a species-specific model of potential suitable habitat called DISTRIB (Iverson et al., 2008). Model simulations will test fire-climate-vegetation feedbacks, allowing the dynamically generated fires of MC1 to influence the species composition predictions of DISTRIB and the species composition predictions of DISTRIB to influence the fuel load in MC1.  Models will be driven with new downscaled 4 km2 resolution climate datasets (historical PRISM baseline, 3 GCMs, 3 emission scenarios) to test fine-scale fire-climate-vegetation interactions along the AT.


Dominique Bachelet - Oregon State University
Louis Iverson - USDA Forest Service Northern Research Station
Anantha Prasad - USDA Forest Service Northern Research Station