Population structure, composition and abundance of elephants Elephas maximus in Minneriya National Park, Sri Lanka

Abstract

The Minneriya National Park was established mainly to enhance the long-term survival of the Asian elephant (Elephas maximus) in a predominantly agricultural area in Sri Lanka. The ancient reservoir, after which the Park is named, is seasonally home to large numbers of elephants because of the availability of water and the extensive areas of grassland created by fluctuations in the water level. In a preliminary study carried out from September 2000 to August 2001, a total of 974 elephants were recorded, of which 797 were classified according to age and sex. A quarter of the observations referred to solitary males. The most frequently observed grouping comprised 5-10 individuals that represent the family unit. The population structure appears to be equally divided between the adults and the other categories. The observed mean adult male: female sex ratio was 1 :2.9, close to the national average of 1 :3. Large groupings of elephant were observed when the drop in water level in the reservoir resulted in increase in the area of the grazing grounds. The largest group observed comprised 70 animals. There were also all-male groups, whose composition varied from 2-6. Most of the animals were observed emerging from the forest to feed on the grasslands between 1600-1700 hrs in the evening. During the rainy season, as the water level in the reservoir increased, flooding the grazing grounds, elephants moved to areas outside the Park, causing conflict with the farming community. The gradual build up of elephants in the Park leading to the observed maximum of3 19 animals, translates into a crude density of 3.6 animals per sq. km, which is among the highest densities recorded in Asia. Therefore Minneriya National Park represents one of the important areas for elephant conservation in Sri Lanka. But the survival of the elephant outside the protected area can only be assured if appropriate measures are adopted to reduce the human elephant conflict.