2020 ESA Annual Meeting (August 3 - 6)

PS 7 Abstract - The effects of human conflict on the population structure of the Asian elephant (Elephas maximus)

K. Budd and Lori S. Eggert, Division of Biological Sciences, University of Missouri, Columbia, MO
Background/Question/Methods Asian elephants, Elephas maximus, like their African counterparts, are heavily reliant on large home ranges of relatively homogeneous landscapes that if fragmented can place them at an increased risk for genetic isolation, dispersal limitation, and overall population decline. Although their endangered status has been largely attributed to habitat degradation, urbanization, and fragmentation, only 16% of their habitat and geographic range is protected. We examined human-elephant conflict in two independent studies that were opportunistic in their initial design and were uniquely situated to study the before and after effects of human conflict on elephant populations. The first was located in central Laos, specifically in the Nakai plateau within the Nakai-Nam Theun protected area, which once represented the largest population in the country and highest genetic diversity ever recorded in Asian elephants. However, in 2010 the elephants of the Nakai Plateau underwent a massive habitat transformation due to the completion of the NT2 hydroelectric and creation of the country’s largest reservoir; resulting in an estimated 40% loss of suitable elephant habitat. The second study features the elephants of Bago Yoma, Myanmar. This area was identified previously as a human elephant conflict hotspot due to the high rates of poaching with annual deaths of humans and elephants considered high for the area. Over the past decades, shifting villages have encroached on Bago Yoma, increasingly bringing people into contact with wild elephants; resulting in large numbers poached for the skin, ivory, and captive elephant trades. We sampled feces from wild individuals in both locations across years spanning pre- and post- conflict events. Data collected included genetic samples, bolus circumference as a proxy for age class, and landscape variables. Using nuclear microsatellite and mitochondrial genetic markers as well as sexing enzymes, we monitored individual elephants across years of conflict.

Results/Conclusions Overall, we found decreased genetic diversity following conflict in both studies with key population demographics altered including sex ratios skewed toward females, age distribution shifts, and fewer family units within herds. As ecosystem engineers, elephants are necessary to the Southeast Asian landscape and small changes to their populations can have large direct effects on the environment surrounding them. These studies demonstrate a unique opportunity to study the long-term effects of human conflict with a long lived, multigenerational species with which human conflict is the primary driver of population decline, traits that are shared by many endangered species across the globe.