Genetics, ecology, and conservation of the Asian elephant.

摘要

I have investigated the genetics and ecology of the Asian elephant, Elephas maximus, and the implications for its conservation and management. Logistic constraints and the conservation status of Asian elephants makes procurement of samples for genetic analysis from free ranging individuals difficult. The use of dung as a source of DNA was a possible solution but posed some technical difficulties. I developed a technique which overcame these problems and demonstrated that dung was a reliable source of DNA for the study of elephants. The technique is applicable to a wide range of taxa including birds, reptiles and insects. Using this technique and PCR amplification and sequencing of mitochondrial DNA, I analyzed population structure and phylogeography of Asian elephants. Populations were significantly subdivided at continental and regional levels. Individuals of two clades with a Pliocene divergence coexisted at some locations. Shared genotypes between the mainland and Sri Lanka refuted the putative subspecies status of Sri Lankan elephants.; Radio telemetry and observational methods were used to study association and ranging behavior of elephants in southern Sri Lanka. Association data, in combination with genetic sampling of individuals confirmed a matriarchal social system. Contrary to previous reports, there was no support for a level of organization more complex than the family. Results of this study demonstrated that non-conservation areas were important feeding grounds for elephants in the dry season. Observations of patterns of habitat use by elephants indicated the possibility of using habitat modification as a management tool. Since monitoring diet composition is important for assessing results of habitat management and no reliable method was available for elephants, I investigated the utility of microhistological fecal analysis for this purpose. It was found to be an accurate estimator of diet composition in elephants.; Human-elephant conflict is the main impediment to the conservation of the Asian elephant. Investigation of its causation and attempted solutions in north-west Sri Lanka indicated that the continued presence of elephants was incompatible with existing landuse patterns. Finally, I evaluated current efforts and reviewed future options for the conservation and management of the Asian elephant.