Habitat
alteration increases invasive fire ant abundance to the detriment of
amphibians and reptiles
Brian D. Todd1, Betsie B. Rothermel1, Robert N.
Reed2, Thomas M. Luhring1, Karen Schlatter1,
Lester Trenkamp3, and J. Whitfield Gibbons1
1Savannah River Ecology Laboratory, The University of Georgia,
Drawer E, Aiken, SC 29802, USA
2Invasive Species Science, USGS Fort Collins Science Center,
2150 Centre Ave, Bldg C., Fort Collins,
CO 80526, USA
3Department of Biology, Southern Utah University, 351 W.
University Blvd., Cedar City, UT 84720, USA
Abstract:
Altered habitats have been suggested to facilitate red imported fire ant
(Solenopsis invicta)
colonization and dispersal, possibly compounding effects of habitat alteration
on native wildlife. In this
study, we compared colonization intensity of wood cover boards by S.
invicta among four forest management treatments in South Carolina,
USA: an unharvested control (>30 years old); a partially
thinned stand; a clearcut with coarse woody debris retained; and a clearcut
with coarse woody debris
removed. Additionally, we compared dehydration rates and survival of recently
metamorphosed salamanders
(marbled salamanders, Ambystoma opacum, and mole salamanders, A.
talpoideum) among treatments.
We found that the number of wood cover boards colonized by S. invicta
differed significantly among treatments, being lowest in the unharvested
forest treatments and increasing with the degree of habitat alteration.
Salamanders that were maintained in experimental field enclosures to study
water loss were unexpectedly subjected to high levels of S. invicta
predation that differed among forest treatments. All known predation by
S. invicta was restricted to salamanders in clearcuts. The amount
of vegetative ground cover was inversely related to the likelihood of
S. invicta predation of salamanders. Our results show that S.
invicta abundance increases with habitat disturbance and that this
increased abundance has negative consequences for amphibians that remain
in altered habitats. Our findings also suggest that the presence of invasive
S. invicta may compromise the utility of cover boards and other
techniques commonly used in herpetological studies in the Southeast.
Key
words: Ambystoma, Clearcutting, Cover boards, Forest management,
Mole salamander, Solenopsis invicta
SREL Reprint #3064
Todd, B.
D., B. B. Rothermel, R. N. Reed, T. M. Luhring, K. Schlatter, L. Trenkamp,
and J. W. Gibbons. 2008. Habitat alteration increases invasive fire ant
abundance to the detriment of amphibians and reptiles. Biological Invasions
(2008)10: 539-546.
