White-handed gibbon (hylobates lar) core area use over a short-time scale

Abstract

Core areas represent small regions within animal home-ranges intensively used during a given period of time. We assessed the quality of core areas relative to the rest of the home-ranges (i.e., non-core areas) of 11 groups of the territorial and highly frugivorous white-handed gibbon (Hylobates lar) over a short-time scale to reflect temporarily available resources. Weekly core areas included consistently higher densities of the gibbons' important foods compared to non-core areas. Gibbon core areas partially overlapped at 46 percent with a model comprising the best hypothetical core areas based on a concentration map of available food sources. In addition, a maximization ratio estimated by dividing the cumulative dbh covered by gibbon core areas and the model reached an intermediate value. Gibbon core areas only partially mirrored food distribution probably because they represent a trade-off between covering regions with important food locations and areas needed for other biologically relevant activities such as territory defense. Results do not support the concept that core areas can represent the minimum area requirement that would allow a gibbon group to survive and reproduce successfully irrespective of the time period considered, which indicates that core areas alone should not be treated as a conservation target. © 2014 The Association for Tropical Biology and Conservation.