Measuring Chimpanzee food Abundance.

Abstract

The assessment of food abundance is critical to address many theoretical questions concerning chimpanzee ecology and social organization. A variety of methods have been used to estimate habitat-wide food abundance. Since methods vary between sites, it is difficult to make meaningful intersite comparisons, without calibration of the different methods. We compare three methods used to estimate fruit abundance simultaneously in the Kibale Forest Reserve, Uganda. Estimates of fruit abundance derived from fruit traps were not related to estimates derived from either systematic transect sampling or estimates obtained from observing fruiting phenology of key species on a fruit trail. However, estimates based on fruit trail data and transect data were correlated. We also report the results of surveys for herbaceous food availability using data from three different sites, employing similar, but not identical methods. The results of these analyses illustrate the difficulties encountered when data generated by divergent methods are compared, and we present specific recommendations as to how future studies might be structured to facilitate comparability between sites. Key Words: food abundance / fruit / terrestrial herbaceous vegetation / methods / Kibale Forest / Uganda / Lomako Forest / Zaire / Ndoki Forest / Congo Factors which have shaped the evolution of differences in grouping behavior and social interactions between Pan paniscus (bonobos) and Pan troglodytes (chimpanzees) remain unclear. Both species have fission-fusion societies, but bonobo parties are sometimes larger than those reported for chimpanzees and are more often mixed in composition (composed of animals of both sexes and all ages) (Badrian