Choice of analytical method can have dramatic effects on primate home range estimates
- 465 Downloads
Primate home range sizes can vary tremendously as a consequence of the analytical technique chosen to estimate home range. This is exemplified by a recent dataset on free ranging snub-nosed monkeys (Rhinopithecus bieti) in Northwest Yunnan, China. Our findings show that the grid cell method cannot substitute for the minimum convex polygon (MCP) method and vice versa. MCP-based estimates are far too large, especially when the form of the home range is irregular due to forays into peripheral areas. Here, we propose an adjusted polygon method, whereby unsuitable and never visited areas are clipped out from the polygon, thus producing more accurate results. Compared to the grid cell method, the adjusted MCP is much more robust when the number of group relocations is limited; MCP turned out to be the method of choice for calculation of monthly and seasonal home ranges. The grid cell method on the other hand yielded the most precise estimates for total or annual home ranges. The style of ranging exhibited by a given primate taxon or population determines which analytical procedures should be applied to estimate home range size, and we would stress the need for thorough evaluation of the pros and cons of home range estimators before conducting field work and analysing data.
KeywordsGrid cell method Home range estimates Minimum convex polygon Primate
Jiaoyan Zhuang is acknowledged for helping with GIS analyses, and Lao Feng, Xuesheng Feng and Xuewen Feng for helping with GPS data collection. The following granting agencies supported the research: Janggen-Pöhn-Stiftung, A. H. Schultz Stiftung, Zürcher Tierschutz, Zoological Society of San Diego, Offield Family Foundation, Primate Conservation, Inc., G. & A. Claraz-Schenkung, Goethe-Stiftung, Schweizerische Akademie der Naturwissenschaften SANW, and Primate Action Fund of Conservation International.
- Fashing PJ, Mulindahabi F, Gakima J-B, Masozera M, Mununura I, Plumptre A, Nguyen N (2007) Activity and ranging patterns of Angolan black-and-white colobus (Colobus angolensis ruwenzorii) in Nyungwe Forest, Rwanda: possible costs of large group size. Int J Primatol 28:529–550Google Scholar
- Macdonald D, Ball F, Hough N (1980) The evaluation of home range size and configuration using radio tracking data. In: Amlaner C, Macdonald D (eds) A handbook on biotelemetry and radio tracking. Pergamon, Oxford, pp 402–424Google Scholar
- Olson DK (1986) Determining range size for arboreal monkeys: methods, assumptions, and accuracy. In: Taub DM, Kay FA (eds) Current perspective in primate social dynamics. Van Nostrand Reinhold, New York, pp 212–227Google Scholar
- Powell R (2000) Animal home ranges and territories and home range estimators. In: Boitani L, Fuller T (eds) Research techniques in animal ecology. Controversies and consequences. Columbia University Press, New York, pp 65–110Google Scholar
- White G, Garrott R (1990) Analysis of wildlife radio tracking data. Academic, San DiegoGoogle Scholar