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Demographic consequences of upland habitat loss on two Ambystoma species in Eastern Massachusetts.
NEWCOMB HOMAN, REBECCA1, WINDMILLER, BRYAN1, REED, J. MICHAEL1, 1
ABSTRACT- The consequences of removing upland habitat surrounding wetlands may negatively or catastrophically impact amphibians that use the wetland for breeding but also require the upland for foraging and over-wintering. The blue-spotted salamander (Ambystoma laterale) is a Species of Special Concern in Massachusetts and the spotted salamander (A. maculatum) is an upland habitat specialist. We examined the demographic impacts of suburban development on these pond-breeding salamanders by studying two semi-permanent ponds. In 1997, the upland forest surrounding one pond was developed, while the upland surrounding the other pond was largely undisturbed. Between 1996 and 2000, the blue-spotted salamander breeding population increased by 40% at the disturbed site, and by 76% at the undisturbed site. During this same period, the spotted salamanders at the disturbed site decreased by 53%, while increasing by 33% at the undisturbed pond. Blue-spotted salamander age structure did not differ significantly between sites (p=0.39). Spotted salamanders, however, appeared to be younger at the disturbed site (p=0.06). Blue-spotted salamanders have a female-biased sex ratio because of mixed ploidy, and the bias was greater at the disturbed site. Spotted salamander sex ratios are slightly male biased and were similar between sites. These results suggest that both spotted and blue-spotted salamanders are negatively impacted by upland habitat loss. Older spotted salamanders and male blue-spotted salamanders seem to be disproportionately affected.
KEY WORDS: Ambystoma, upland, demographic