Shrinking forest shrinks skink: morphological change in response to rainforest fragmentation in the prickly forest skink ( Gnypetoscincus queenslandiae)

Abstract

Large-scale fragmentation of rainforest occurred on the Atherton Tableland in the Australian Wet Tropics from 50 to 100 years ago, leaving numerous fragments of varying sizes. Eleven fragments (from <1 to 75 ha in area) and eight continuous-forest sites were studied to assess the effects of fragmentation on the morphology and demography of the rainforest-endemic prickly forest skink ( Gnypetoscincus queenslandiae). Skink abundance (number of individuals captured per hour of search effort) was significantly greater in continuous forest than in forest fragments. Moreover, both skink abundance and the availability of decaying logs, which provide key habitat for this species, increased with fragment area. Fragments contained a smaller proportion of adults, and individuals in fragments were smaller on average for all measured morphological features, than those in continuous forest. Thus, although prickly forest skinks appear to be maintaining populations in rainforest remnants, they are nonetheless being affected by fragmentation. These demographic and morphological changes may be caused by alterations in habitat and prey availability and/or by microclimatic changes associated with edge effects.