Estimating elephant densities from wells and droppings in dried out riverbeds.

In this paper, we present a new method for estimating elephant densities by counting elephant wells and dung boli within dry seasonal flooding rivers. A combination of aerial and ground counts of elephant wells and dung boli in the Ewaso Ngiro River were related to elephant numbers, obtained from an on-going monitoring program of individually identified elephants in Samburu and Buffalo Spring National Reserves, Kenya. The total number of elephant observations was highly correlated with both densities of wells and dung boli at a spatial resolution of 4-km river-section. This indicates that both wells and droppings can be used for estimating relative densities at such spatial resolution. The method can be used as a quick and reliable way of estimating relative elephant densities in semiarid regions but is sensitive to differences in the time when different parts of the river dry out and will be unreliable in areas with secondary un-censused water sources. A short 4-week period between the river dry out and the count is recommended, because of an error induced by a level of well reuse and the difficulties in counting areas of high well densities from the air. [ABSTRACT FROM AUTHOR]