Ranging of Rhinopithecus bieti in the Samage Forest, China. I. Characteristics of Range Use

Abstract

We quantified the home range and explored the style of ranging of blackand-white snub-nosed monkeys (Rhinopithecus bieti) in the subtropical-temperate montane Samage Forest (part of Baimaxueshan Nature Reserve) in the vicinity of Gehuaqing. Over 14.5 mo, we took positional records of the study band via a GPS receiver at 30-min intervals, and found that they covered an area of 32 km 2 . Over a 10-yr period, the group even ranged in an area of 56 km 2 , which is among the largest home range estimates for any primate. The large home range was probably due to the combined effects of large group size (N>400) and forest heterogeneity, with seasonally food-rich areas interspersed with less valuable areas. The subjects did not use their home range uniformly: 29% of the grid cells had more location records than expected based on a uniform distribution, thus representing a core area, albeit a disjunct one. A continuous 1-mo group follow in the fall revealed that the band traveled on average 1.62 km/d and that days of concentrated use of a particular forest block were followed by more extensive marches. Neither climate nor human disturbance parameters correlate significantly with monthly estimates of the group's home range size. Even though there is no significant correlation between temporal availability of plant phenophases and range size, our observations implicate temporal and spatial availability of food as a determinant of home range use of the focal group. Winter, Int J Primatol (spring, and summer home ranges are equally large: 18.2, 17.8, and 18.6 km 2 , respectively. Home range decreased markedly in fall (9.3 km 2 ), probably because the band obtained sufficient food resources (fruit) in a smaller area. The large winter range is best attributed to the exploitation of dispersed clumped patches of mature fruits.

Ranging pattern and population composition of Rhinopithecus bieti at Xiaochangdu, Tibet: Implications for conservation

“…We found a significant positive correlation (Spearman's rank correlation, r s =0.852, P<0.001, n=11) between group size and home range among these snub-nosed monkey species (Table 3). The home range of the Xiaochangdu group is approximately 21.25 km 2 ; the larger home range is consistent with other studies of R. bieti [43,44,49,57,58] as well as R. roxellana and R. brelichi (Table 3).…”

“…For instance, R. bieti at Samage ranged over a more limited area in autumn, when fruit available is highest because the monkeys' preferred fruit occurred at high densities in small clumps which ripened synchronously. This caused the monkeys to repeatedly forage in the same patches, increasing daily travel distance without increasing range size [49].…”

“…A group of R. bieti at Wuyapiya, about 100 km south of Xiaochangdu, had a home range of 25 km 2 [43]. Another group of R. bieti with >410 individuals living to the south in the Samage Forest,Yunnan, had a home range of 25 km 2 [49], while a group of approximately 180 individuals occupied 23.3 km 2 at Jinsichang, Yunnan [58]. Generally speaking, complex vegetation profiles mean high food availability and high population density for leaf-eating monkeys.…”

Home range and seasonality of Yunnan snub‐nosed monkeys

“…The estimate method used by Bai and coauthors (1988) is questionable: no group had been systematically located over a relatively long period (a season or a year) and the estimations of home ranges were very rough. Given a 410 natural group of R. bieti never occupied a larger home range (only 32 km 2 , Grueter et al 2008) more than 40 km 2 , we suggest that home range sizes over 40 km 2 should be cautiously used for comparison (e. g. not a natural group or calculating the home range by a wrong method). Then group size does not correlate with home range size in R. bieti, which is similar to the result in folivorous primates, such as Colobus guereza Rueppell, Table 4 Comparisons among home range sizes (km 2 ) in different sized squares by the grid-cell method 1835 (Krueger et al 1998) and Lemur catta L., 1758 and Eulemur fulvus rufus Geoffroy, 1812 (Overdorff 1996).…”

Range Expansion as a Response to Increasing Group Size in the Yunnan Snub-Nosed Monkey

“…Currently, only 17 groups of R. bieti remain in the wild [Long and Wu, 2008]. Previous studies have estimated home range size of R. bieti based on 1-or 2-year-long investigations [Kirkpatrick, 1996;Yang, 2000;Cui, 2003;Grueter et al, 2008;Ren et al, 2009], which confirmed a large home range ( 1 20 km 2 ) and group size ( 1 100 individuals). To date, however, no study has focused on the relationship between home range and group size in R. bieti .…”