Amphibian responses to conventional and reduced impact logging

Abstract

Unsustainable timber management, primarily via Conventional selective Logging (CL), has resulted in severe habitat degradation and biodiversity loss. Sustainable techniques, principally Reduced Impact Logging (RIL), are therefore essential for conserving highly threatened, physiologically sensitive taxa such as amphibians. In this study we compare the effects of CL and RIL on stream amphibians across a regeneration gradient in two forest reserves in Sabah, Malaysian Borneo. We analysed data from a community of stream amphibians across 29 transects subject to either CL (18 – 21 years since logging) or RIL (4 – 21). Multi-species occupancy modelling determined community and species responses to logging types, regeneration times and logging associated environmental factors. Diversity profiles, which capture representative diversity indices whilst accounting for community evenness, were calculated using occupancy model results. Our results indicated that several species and community occupancy generally responded negatively to logging associated covariates (lower aboveground carbon density and higher siltation). Stream breeding species occupancy was generally lower in CL compared to RIL sites, with higher generalist breeding species occupancy in CL sites. Diversity profiles identified higher anuran diversity and evenness in RIL compared to CL sites of the same age (18 – 21 years). Furthermore, anuran diversity and evenness exhibited a distinct recovery from 4 to 21 years following RIL. Our results provide strong evidence that RIL reduces the negative impacts on stream habitats, amphibian occupancy and diversity compared to CL, and suggest a far quicker recovery after RIL. We believe RIL presents a promising alternative for sustainable tropical timber management and stream amphibian conservation.