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Resource distribution and group size in the common langur Semnopithecus entellus in southern India
Author(s) -
Vasudev Divya,
Kumar Ajith,
Sinha Anindya
Publication year - 2008
Publication title -
american journal of primatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.988
H-Index - 81
eISSN - 1098-2345
pISSN - 0275-2565
DOI - 10.1002/ajp.20549
Subject(s) - abundance (ecology) , predator , wildlife , resource distribution , basal area , predation , national park , geography , ecology , biology , distribution (mathematics) , demography , mathematics , mathematical analysis , management , sociology , economics , task (project management)
We investigated the influence of resource abundance and distribution on the group size and composition of the common langur Semnopithecus entellus in the contiguous forests of Bandipur National Park, Mudumalai Wildlife Sanctuary and Nagarahole National Park in southern India. We also explored any additional effect of predator pressure and the risk of take‐over on the same attributes. Data on group composition and vegetation were collected from January to May 2006. The size and composition of 94 bisexual groups were obtained. The group size varied from 7 to 40 and the groups included unimale and multimale groups. Thirty‐five all‐male groups were encountered. Vegetation was sampled from 17 grids of dimension 1 km × 1 km, each containing twelve 25 m × 25 m plots. The list of food species was compiled from previous studies and observations made during the study period. The mean basal area of all the food trees within each plot and its coefficient of variation at the level of the grid were used to represent resource abundance and distribution, respectively. The number of adult females and males within groups were analyzed separately to test for differential effects on age–sex categories. Group size increased as resources became spatially more heterogeneous. The abundance of resources had a negative effect on group size. This study did not find evidence supporting the direct effect of predator presence or of the risk of take‐over. Contrary to what were expected, adult males reacted more strongly and predictably to resources than did adult females. The group attributes and their relationship with food resource abundance and distribution differed between two sites in the study area possibly owing to langur subspecies differences. Am. J. Primatol. 70:680–689, 2008. © 2008 Wiley‐Liss, Inc.