Effects Of Group Size In Habitat Use And Home Range Of White-headed Langur (Trachypithecus Leucocephalus)

White-headed langurs(Trachypithecus leucocephalus)are unique primate inhabiting in the limestone habitat.White-headed langur only distribute in Guangxi,they are limited in a triangle area of 200 km~2 between Zuojiang River and Mingjiang.The white-headed langurs has been influenced by the high-intensitive human activities and habitat fragmentation.As a result,their habitat was limited of food resources.We predict that the increasing of individuals number will intensify the group composition,and group size will influenced the langur’s foraging behavior.From September 2017 to August 2018,we collected data on the diet,activity time budget and ranging behavior of four group of White-headed langurs(two large group:G-DS and G-ZWY;two small group:G-LZ and G-NN)in Chongzuo White-headed Langur National Nature Reserve,Guangxi Province,China.We compared of habitat use,home range and ranging behavior for white-headed langur different group size.To make clear how the effects of group size on behavior,and found the evidence of foraging competition and the ecological constraints of this folivorous primate in the karst habitat.The results were as following:1.The langurs Selection of Mountain site.G-DS group:The use of mountain2.8±3.49%,cliff 50.17±7.72%,hillsides 24.43±11.18%,foot 22.6±12.17%and Farming land0%.G-ZWYgroup:The use of mountain 0.91±0.79%,cliff 44.73±7.39%,hillsides24.11±4.2%,foot 29.42±6.19%and Farming land 0.84±1.15%.G-LZ group:The use of mountain 2.72±2.34%,cliff 66.67±8.03%,hillsides 27.77±8.52%,foot 2.85±2.91%and Farming land 0%.G-NNoup:The use of mountain 5.7±2.62%,cliff 64.62±13.41%,hillsides23.24±10.39%,foot 6.57±5.83%and Farming land0%.There were significant differences in the utilization of mountain sites among monkeys of different sizes.2.The annual utilization ratio to slope direction of G-DS group:Non-sloping occupation23.37±11.73%;Eastward occupation4.65±2.7%;Southward occupation 26.67±15.23%;Westward occupation20.79±7.98%;Northward occupation21.52±9.2%。The annual utilization ratio to slope direction of G-ZWY group:Non-sloping occupation 26.39±12.03%;Eastward occupation 14.96±6.24%;Southward occupation 12.04±4.24%;Westward occupation 11.72±4.28%;Northward occupation 7.29±3.7%。The annual utilization ratio to slope direction of G-LZ group:Non-sloping occupation 4±3.37%;Eastward occupation 12.96±6.88%;Southward occupation 57.2±5.11%;Westward occupation22.14±7.13%;Northward occupation 3.7±3.31%。The annual utilization ratio to slope direction of G-NN group:Non-sloping occupation 4.16±3.22%;Eastward occupation 14.1±7.39%;Southward occupation 1.47±1.99%;Westward occupation 8.23±7.34%;Northward occupation 62.04±9.5%。Compared with small groups,large groups make use of more slope-free foothills,while there is no significant difference in other slope utilization.3.The daily path length were different between different group size.The G-DS has an average daily path length of 455.6±43.8 m m,the G-ZWY with 499.1±108.0 m,the G-LZ with 430.4±78.0 m and the G-NN with 63.1±61.4 m.The large group has a longer average daily path length than the small group.4.Group size influenced the behavior of white-headed langur.With the increasing of group size,langurs will increase the use of food-rich foothills at the foothills and reduce utilization of cliffs.langurs will increaselonger average daily path length.Our results support the prediction of ecological constraints model on group size.