Assessing Threats to Ungulates and Management Responses

1. Adverse human impacts have often been drivers of general biodiversity loss, and specifically decline of large ungulates in tropical forests, even within designated nature reserves. However, effectiveness of conservation efforts in protected areas is constrained in the absence of reliable assessments of prevalent threats to wild ungulate populations. Similar constraints are faced while assessing population responses to specific management or conservation actions. In this study, using five threatened species of ungulates in the Nagarahole-Bandipur landscape as examples, we illustrate how rigorous assessments of both human impacts and management actions can be made at landscape scales. We submit these approaches have broader application to efforts to protect and recover other mammalian taxa and even overall biodiversity. 2. We specifically quantify how different anthropogenic activities are affecting the Nagarahole-Bandipur landscape and elucidate the critical need for establishing rigorous monitoring systems for assessing such threats as an integral part of ungulate management efforts. Our focus here is primarily to (a) predict human impact at a broad scale (landscape level) from local scale (transect level) data on human disturbances, and (b) predict the response of ungulate populations to these impacts, based on ungulate-habitat association hypotheses and factors governing them. 3. We measured human impacts using the system of line transects designed for estimating ungulate abundance. We then predicted human impacts at each 1-km2 grid-cell level by modeling the relationship between a composite human disturbance index and distances to human settlements, and forest protection camps that regulate their impacts. We mapped the distribution of human impacts to identify ‘vulnerable zones’ for ungulates and to improve potential management responses. 4. We reviewed a range of current management practices in the study landscape to identify and categorize these interventions as either habitat enrichment or habitat protection. We assumed that any management response under these two categories would lead to some corresponding change in the values of relevant predictor variables in the ungulate abundance model. Based on our models of ungulate-habitat relationships (Chap. 3), we predicted ungulate population responses to different management interventions. We examine relative contributions of different interventions to influence ungulate abundance to prioritize effective interventions. 5. We discuss the utility of our spatially explicit hierarchical modeling approaches for future evaluation of conservation and management of threatened study species. We also discuss the implications of our work to other similar conservation contexts in the tropics.