Threshold responses in wildlife communities and evidence for biodiversity indicators of sustainable resource management

Abstract

Conservation of communities of wildlife may conflict with forestry due to the impacts of habitat alteration to wildlife and desire by the public for economic development. Identification of thresholds to disturbance and habitat conditions may improve our ability to find compromises between conservation and resource development, while also identifying sensitive indicators. We used the multivariate Threshold Indicator Taxa Analysis (TITAN) to assess the response of a wildlife community to disturbance from forest harvest, roads, and forest habitat affected by forest management. Significant thresholds were evident among birds, amphibians and mammals, and patterns in positive and negative responses appeared to vary in relation to life history adaptations. Birds typically had the strongest relationships to environmental gradients and provided good representation of a range of forest conditions useful in assessing sustainability in forestry. We found that negative indicator responses to forest habitat gradients were often more precise and synchronous among species than positive responses, potentially affected by the diversity of habitat niche space among species. Stronger responses among a greater range of species were evident for resource-providing habitat conditions than direct measures of disturbance (i.e. forest cuts and roads). Our approach demonstrates the value of identifying ecological community thresholds that can serve to set targets for conserving biodiversity and to characterize community dynamics in response to habitat change mediated by natural resource management.