Responses of Long-Tailed Macaques to Drought and Fire in Eastern Borneo: A Preliminary Report

Abstract

During a 20-month study that spanned a severe drought and forest fire in a Bornean rain forest, a group of long-tailed macaques adapted successfully in the short term to extreme habitat damage by shifting to less preferred food items and exploiting an insect outbreak while fruits and flowers were scarce. Charred and desiccated fruits were major food sources just before the insect outbreak. The group dispersed widely to forage and increased its terrestrial travel. Riverine refuging became more erratic late in the drought and after the fire. The continued presence of sizable populations of this and other diurnal primate species, relative to those of some other frugivores with fixed home ranges and more restricted diets, suggests that dietary breadth is an important factor mediating frugivore responses to habitat degradation. FROM JUNE 1982 THROUGH MAY 1983, the El Ninio Southern Oscillation caused drought and forest fires in East Kalimantan, Indonesia (eastern Borneo), severely damaging approximately 3 million ha of evergreen forest, including large tracts of swamp forest, peat forest, and both selectively logged and undisturbed lowland rain forest (Anonymous 1984, Leighton & Wirawan, in press). My field study of the behavioral ecology of long-tailed macaque monkeys (Macacafascicularis) in the Kutai National Park, conducted from January 1982 through September 1983, spanned the entire drought, fire, and a 5month post-fire period, enabling me to record the responses of one group of macaques to drastic ecological change. In this paper I describe some of the monkeys' feeding and ranging responses. Leighton and Wirawan (in press) provide a general account of the effects of drought and fire on Kutai flora and fauna.