Genetic Analyses of Non-invasively Collected Samples Aids in the Conservation of Elephants

Abstract

Elephants, which are among the most high-profile of the charismatic megafauna, are increasingly found in the human-dominated landscapes outside protected areas, creating the potential for serious economic impacts and tragic consequences for both humans and elephants. Managing elephants and other wide-ranging species requires information about population and group sizes, demography, distribution and habitat connectivity. Although we can view African savannah elephants (Loxodonta africana) from the air and estimate population sizes and movements through direct observations, these data are especially difficult to obtain for African forest elephants (Loxodonta cyclotis) and Asian elephants (Elephas maximus), as aerial surveys cannot detect animals under the closed canopy and ground surveys cannot be performed due to the dense vegetation. The case studies presented here illustrate the power of genetic studies using DNA obtained from non-invasively collected samples to provide biologists with important insights at the individual and population levels. In the Rift Valley of southern Kenya, the use of these methods allowed researchers to infer the movement patterns, demography and stress levels of a recently reestablished population of African savannah elephants on Maasai community land. Although behavioral studies of African forest elephants have suggested that social groups are predominately made up of a single female and her offspring, genetic analyses revealed evidence of weak, but significant, kin-based social structure comparable to the family groups observed in African savannah elephants. For the Asian elephant population of the Nakai Plateau, Lao PDR, genetic analyses allowed researchers to infer population size and demographic structure, and to estimate the level of genetic diversity. Despite having a considerably smaller population size than those found in India and Sri Lanka, the genetic diversity of the Nakai elephants continues to be among the highest reported in Asian elephants, highlighting the conservation value of this and other small, isolated populations in southeast Asia. These studies illustrate the breadth of information that can be obtained and highlight the use of genetic data in the conservation of these keystone species.