Rainfall and the population dynamics of elephant dung-piles in the forests of southern Ghana

Decaying dung-piles were observed at three sites in the lowland forests of southern Ghana. Time to disappearance was inversely related to rainfall in the month of deposition. The monthly survival of each age-class decreased with age and was inversely proportional to rainfall in the month of deposition. A simulation revealed that if elephant numbers and defaecation rates are constant, then dung density in a given month will be governed by rainfall in the two preceding months. Changes in annual rainfall and its monthly distribution in southern Ghana mean that dung-pile densities will vary from one month to the next, and between the same months in different years, even if elephant numbers are constant. Thus dung counters must take rainfall into account. A new method of censusing elephants in Ghana is presented, and suggestions are made for improving elephant counts in central African forests.