American chestnut (Castanea dentata) habitat modeling: identifying suitable sites for restoration in Shenandoah National Park, Virginia
Abstract
Since 2008, The American Chestnut Foundation’s (TACF) Appalachian Trail MEGA-Transect
Project has engaged citizen scientists to collect American chestnut occurrence data
over the length of the Appalachian Trail. This data helps TACF to locate surviving
trees for use in their breeding program and expand their knowledge of chestnuts across
the East Coast. However, this dataset is limiting in that it considers only the ridge-top
habitat of the trail. To remedy this, we conducted an extensive sampling of side-trails
in Shenandoah National Park in order to study more diverse elevation and habitat gradients.
Expanding the dataset allows us to draw more informed conclusions about habitat for
surviving American chestnuts. To achieve this, I developed a series of species distribution
models, including GLM, CART, and Maxent models, based on field observations and spatial
data of environmental variables. These predictive distribution models were then combined
to generate a comprehensive map of the most likely surviving American chestnut occurrence
locations across Shenandoah National Park. Additionally, projections based on future
climate were made for the Maxent model to 2050 and 2070 in order to see if habitat
for surviving trees might shift in the face of climate warming. Overall, the three
species distribution modeling techniques tended to agree on location, but not quantity,
of suitable habitat for surviving chestnuts. All models found elevation, sand, and
slope to be the most significant habitat predictors in Shenandoah. Climate change
models produced only subtle range shifts; as a generalist species, American chestnuts
may not face adverse effects of future climate warming. Mapping these results provides
valuable information to both Shenandoah National Park and TACF as they continue to
search for, study, and restore American chestnuts in the Appalachian forest.
Type
Master's projectSubject
species distribution modelingAmerican chestnut
restoration
climate modeling
Maxent
habiat suitability
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https://hdl.handle.net/10161/8176Citation
Santoro, Jennifer (2013). American chestnut (Castanea dentata) habitat modeling: identifying suitable sites
for restoration in Shenandoah National Park, Virginia. Master's project, Duke University. Retrieved from https://hdl.handle.net/10161/8176.Collections
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