GENETIC-STRUCTURE OF REDBACK SALAMANDER PLETHODON-CINEREUS POPULATIONS IN CONTINUOUS AND FRAGMENTED FORESTS

Fragmentation of natural habitats is increasing dramatically, yet its effects on the distribution of genetic variation in wild populations r emain largely unknown. In this study, two woodland populations of the redback salamander Plethodon cinereus in Connecticut, USA, were contra sted using molecular and morphological markers. One population was fro m a landscape fragmented for 300 yr by human activities and another fr om a nearby, undisturbed landscape. Genetic differentiation, based on molecular markers, was marginally greater in the fragmented population than in the contiguous population, and, within the fragmented populat ion, was greater among subpopulations lacking historical forest connec tions. Genetic divergence between subpopulations was also weakly relat ed to geographic distance in the population occupying continuous fores t, but not in the population occupying fragmented forest. Fragmentatio n enhanced morphotype diversity within populations of P. cinereus, whe reas levels of molecular genetic diversity within subpopulations were apparently unaffected. (C) 1998 Elsevier Science Ltd. All rights reser ved.