Publications [#153455] of Leslie J. Digby

Papers Presented/Symposia/Abstracts

1. L.J. Digby, A new approach to primate home ranges: Using 3D and 4D data to calculate home range volumes and use, International Journal of Primatology - Abstracts (2008)
   (last updated on 2008/12/18)

   Abstract:
   Home ranges are a key element to most field studies of primate behaviour and ecology. Home range can be used to determine the impact of changes in resource availability, group size, and interspecies competition. As such, accurate calculation of use of space is essential. While there have been improvements in how we estimate home range use (e.g., least polygons and kernel estimators) all continue to use only 2D measures. For arboreal species, this leaves out an entire dimension – height. Here, I describe a new method for determining 3D home range volumes using three species of semi-free ranging lemurs housed in a large (11+ ha), forested enclosure at the Duke Lemur Center. Using focal animal sampling, the location of the animal was recorded every five minutes using hand-held GPS units along with the animal’s height in the trees. All three groups had home range “areas” of approximately 2 ha (range: 1.7-1.9 ha), but differed greatly in their use of height (12m – 30m max. height). The resulting home range “volumes” thus differed substantially: Lemur: 202,000 c3; Eulemur: 468,000 c3 ; Varecia: 576,000 c3. These calculations were determined using a “stacked grid” method, but “stacked polygons” could also be used. Ultimately, these more complete descriptions of home range use, in conjunction with new technologies that will allow for 24/7 data collection (e.g., GPS collars), will allow for the calculation of 4D (x,y, z coordinates + time) home range use and interactions and for a more complete understanding of primate home ranges.