Study On Food And Spatial Niche Similarity Of White-headed Langur(Trachypithecus Leucocephalus) And Francois’langur (T.Francoisi), In Chongzuo, Guangxi

White-headed langur (Trachypithecus leucocephalus) and Francois’Langur (T.francoisi) are unique primates inhabiting in the limestone habitat. White-headed langur only distribute in Guangxi, they are limited in a triangle area ca200km2between Zuojiang River and Mingjiang River. Francois’ Langurs’ distribute is opposite to Zuojiang River and Mingjiang River. Their habiatats are adjancet but allopathic. They are physically and physiologically similar, combined with the similar habitat, and distribution pattern, we predict that they might behaviorally similar. From January to December2013, we studied the niche similarity of the two langurs in Fusui by Instantaneous Scan Sampling. The results were as following:1. White-headed langur and Francois’ Langur both are typical folivorous primates. Leaves were their main food source, accounting for67.4%and67.7%of the diet respectively. Fruit accounted for13.0%and17.9%of the diet respectively. Flower, seed and the other plant parts constituted for less than10%of their diet. There was marked inter-specific similarity in annual food category composition in terms of monthly percentages of feeding records for different food categories. It was similar in food category utilization by the two langur species in rainy season and dry season.2. White-headed langur consumed104species and Francois’ Langur ate98species. Among the food species,69species were shared by both (50.0%of total food species). There was a more marked similar between major foods species (accounting for1%of all feeding records). Among the32major food species,17species were shared by both (53.1%of major food species).It means that there is intense competition in food species between two langur species assuming that their distribution areas is overlap each other.3. Food niche breadth of White-headed langur and Francois’ Langur was4.02and3.71, respectively, indicating a wide niche compared to other unhuman primates. The integrative food niche breadth of white-headed langur was more wider than Francois’ Langur’s except for April. Mean similarity index (PS) of food niche was0.59, ranging between0.27and0.61in different months. Similarity index was0.66when major foods were compared. It means that there was a high degree of similarity in food niche between two langur species and the major food of them was very similar.4. There was similar variation in the use of different zones of the limestone hill. White-headed langur and Francois’Langur were often observed to use cliff, and the former used more hillside and valley. Similar patterns of habitat utilization by the two langur species were found in both rainy season and dry season. White-headed langurs spent nearly equal time in canopy, middle level and ground (ca.30.0%each). Francois’ Langur spent more active time on the lower canopy height (up to50.0%). The spatial niche similarity of two langur species varied between0.76and0.94, indicating an intense competition between two species, and they are hard to coexist once the two species are distributed sympatrically.