Effects of forest removal on amphibian migrations: implications for habitat and landscape connectivity
Brian D. Todd1, Thomas M. Luhring1, Betsie B. Rothermel1,2, and J. Whitfield Gibbons1
1Savannah
River Ecology Laboratory, Drawer E, University of Georgia, Aiken, SC
29802, USA
2Archbold Biological Station, PO Box 2057, Lake Placid, FL
33862, USA
Abstract
:
1. Habitat loss is a leading cause of global amphibian declines. Forest
removal is a particularly significant threat because an estimated 82%
of amphibians rely on forests for part of their lives.
2. Biphasic amphibians rely on suitable terrestrial habitat to support
their post-metamorphic growth and survival and also to maintain appropriate
habitat and landscape connectivity.
3. We created 4 replicate, 16-ha experimental arrays in the southeastern
USA to examine the effects of forest removal on migratory movements of
adult biphasic amphibians. Each array contained four forest-harvesting
treatments that included an unharvested control, a partially harvested
stand, a clearcut with coarse woody debris retained, and a clearcut with
coarse woody debris removed.
4. Some amphibian species emigrated from wetlands in significantly greater
numbers through forest controls compared with harvested treatments. Also,
salamanders were generally more sensitive to forest removal than were
frogs, with a significantly greater proportion of salamanders migrating
through forested habitat compared to frogs.
5. For several species, individuals were significantly more likely to
avoid clearcuts when emigrating compared to immigrating. Individuals that
emigrated into clearcut treatments were more likely to reverse direction
and return to wetlands in some species.
6. Synthesis and applications. Our study identifies one mechanism
by which forest removal shapes the abundance and distribution of amphibians
in terrestrial habitat. To promote the persistence of amphibian populations,
conservation efforts should focus on preserving forest habitat adjacent
to reproduction sites. Such measures are especially important where forest
habitat connects local populations or where it links reproduction sites
to other habitat features necessary for amphibian growth, survival, or
overwintering.
Keywords: Ambystoma, Bufo, clearcutting, forestry, habitat
loss, metapopulation, Rana, timber harvesting
SREL Reprint #3100
Todd, B.
D., T. M. Luhring, B. B. Rothermel, and J. W. Gibbons. 2009. Effects of
forest removal on amphibian migrations: implications for habitat and landscape
connectivity. Journal of Applied Ecology 46(2009): 554-561.
