Abstract # 938 Poster # 86:

Scheduled for Thursday, August 18, 2005 07:00 PM-09:00 PM: (Cambridge/Oxford Room) Poster Presentation

Day Range and Home Range Assessments: A Comparison of GPS and Grid-Based Methods

P. Terranova1, B. C. Wheeler2, C. C. Gilbert2 and S. A. Suarez1
1Stony Brook University, Department of Anthropology, Stony Brook University, Stony Brook, NY 11749-4364, USA, 2Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, Stony Brook, NY 11749-4364, USA
      Comparisons between species and across sites are important when assessing the impact of ecology on habitat use, ranging behavior, and group size effects. However, different methods for measuring ranging behavior may confound such comparisons. Here we analyzed one year's ranging data for a group of wild Phayre's leaf monkeys (Trachypithecus phayrei) in Phu Khieo Wildlife Sanctuary, Thailand, to assess the impact of different methods on day range and home range estimates. At 30-minute intervals from dawn to dusk we used a GPS to obtain UTM (Universal Transvers Mercator) coordinates at the group center, and simultaneously recorded all occupied cells within a grid of 50x50m squares. Grid-based day ranges, calculated using the midpoint of all occupied cells per scan, were compared to GPS day ranges. Mean day ranges for both methods did not differ significantly. Home range size and usage were analyzed using ArcView GIS 3.2. A kernel and MCP (Minimum Convex Polygon) were generated with the GPS data and compared to a grid home range composed of all cells entered. The grid-based home range was comparable to the kernel and the locations of intensely used areas matched; the MCP was absolutely larger than both other estimates. The results indicated that GPS and grid-based ranging data from different sites or species are comparable, and that kernels from GPS data are more suitable than MCPs for comparisons with grid-based methods. Supported by NSF (BCS-0215542).