Monitoring populations of Asian elephants has long been recognized by biologists and government agencies as critically important to conservation and management, but continues to suffer from a number of shortcomings related to poor survey design and field practices, inappropriate application of analytical approaches and a critical mismatch between the focus of monitoring programs and the spatial scale at which these have been attempted. Consequently, frequently cited state-, region- and country-specific ‘numbers’ poorly reflect reality. As pointed out over a decade ago, reliable knowledge of the status of this iconic species barely extends beyond the locations of most populations and estimates of density from a handful of individual protected areas.
Biologists from the Centre for Wildlife Studies and Wildlife Conservation Society-India have published a paper in the recent issue of the international peer-reviewed journal Biological Conservation where they assess different approaches to monitor elephant populations in the light of modern population estimation theory: block and waterhole counts, indirect dun-based estimation, direct line transect surveys of elephants and capture recapture sampling. They discuss potential sources of bias and uncertainty associated with estimates derived using each of these approaches. The authors make specific recommendation on what population parameter(s) to focus on at particular spatial scales, which approaches to use in specific field situations, and provide guidelines for designing, implementing and analyzing population surveys for Asian elephants.
“Sound understanding of the distribution and abundance of a species is a prerequisite for devising appropriate policies at national scale or implementing relevant conservation actions at the grassroots,” said Dr. K. Ullas Karanth, Director of Science, WCS, and a co-author on the study.
“For the very reasons that estimation and monitoring is recognized as being critical for the conservation of elephants and their habitats, unreliable and misleading estimates are a cause for serious concern” said lead author Devcharan Jathanna. “They are, at best, wasteful of time and resources, and at worst, serious obstacles to targeted conservation”.
Based on their experience in monitoring elephants, other large herbivores and large carnivores over the last three decades, the authors of the paper demonstrate that direct line transect sampling of elephants can be used to derive reliable estimates of elephant density, provided a number of design, field and analytical requirements are met. Learning from their own mistakes, the authors also outline a number of common pitfalls to avoid in carrying out line transect surveys for elephants in forests.