Human-elephant interactions at the ecosystem level

Abstract

Elephant populations in the Sebungwe region were studied over a 15,000 sq kms range of mixed natural habitat and human land use. Abundance, spatial organization, and social ecology were compared between a) populations resident in protected wildlife areas, and b) communal lands with human populations. Trends in numbers and densities compiled for the past 16 years, 1980-1996, were stable or declining, contrasting with steadily rising trends of the previous 25 years, 1955-1980. Crude densities outside protected areas rose significantly when converted to ecological densities by excluding human settlement areas, population decline was proportional to agricultural expansion. In communal lands, female elephant home range was estimated to have been compressed by 58% in response to human settlement over the last decade. Widespread displacement of unprotected populations into available refuges was not demonstrated. The prevailing 'linear model' of human-elephant interaction is inapplicable here. An alternative 'flip model' is proposed: elephant and humans coexist at variable levels or abundance until a threshold of land cover transformation is reached in the natural matrix, whereafter elephants disappear.