Some like it hot: Drought-induced forest die-off influences reptile assemblages

Abstract

Vegetation changes as a direct result of climatic shifts changes are likely to influence reptile communities reliant on forest habitat structure and health. Extreme heat and drought over the summer of 2010/11 caused canopy collapse and decline in a Mediterranean-type forest, southwest Western Australia. The loss of canopy and altered abiotic and biotic conditions changed habitat availability for fauna. A survey of reptile assemblages and vegetation was carried out over the summer of 2013/14, three years after the drought event. Reptiles were captured using camera traps and pitfall traps. Surveys were carried out at four independent locations, where trap stations were set up across drought-affected and adjacent healthy (not visibly affected) sites (total 32 trap stations). Habitat variables likely to influence reptile assemblages (leaf litter, coarse woody debris) were measured, and iButtons were used to capture temperatures within microhabitats likely to be used by reptiles. Reptile assemblages observed at drought-affected sites differed to assemblages observed at healthy sites. These differences could be related to warmer and colder temperature extremes in drought-affected sites compared with healthy sites. Coarse woody debris was readily available in drought-affected sites but leaf litter accumulation was significantly less in drought-affected sites compared to healthy sites. Drought events are becoming more commonplace and it is important to understand the repercussions of forest decline on reptile assemblages. More proactive approaches for maintaining native habitat, such as shelter structures, may be required to protect species in affected sites to ensure that ecosystem processes are not lost.