Arboreal primates spend about half of their lives at sleeping sites; hence, selection of sleeping sites is crucial for individual survival, and data concerning them is important for conservation efforts. We collected data on sleeping sites for a group of the endangered snub-nosed monkey (Rhinopithecus brelichi) at Yangaoping (27°58′N, 108°45′E) from January 2006 to December 2007. All sleeping sites were located in the mid-slope and in the shadow of ridges facing the northeast and southeast. The monkeys remained quiet while entering and occupying sleeping sites, and slept in evergreen species during the cold season (December-March). Trees in sleeping sites were similar in height and girth at breast height to those elsewhere, but some trees in lower areas were larger. The monkeys usually slept in close proximity to the last feeding spot, and their daily activities usually occurred around the sleeping site. Areas adjacent to sleeping sites were used more intensively than those not adjacent. Monkeys left the sleeping sites later in the morning in the cold season. These behavioral responses suggested that predation risk, thermoregulation, and climate stresses are the main determining factors in the selection of sleeping sites for this temperate monkey.
Effective population management relies on assessments of population size and sex ratio. However, these estimates are difficult to obtain for elusive and rare species. Recently, noninvasive genetic census methods have been developed as an alternative to traditional capture-mark-recapture methods. In this study, we estimated the size of the Sichuan snub-nosed monkey (Rhinopithecus roxellana) population in the Shennongjia Nature Reserve (SNR) using a noninvasive sampling method based on 16 microsatellite loci. We also used a PCR-based genetic method to sex the sampled individuals and infer the population sex ratio. The population size of R. roxellana in the SNR was estimated to be 1044 individuals (95% CI TIRM : 613-1409). The estimated population sex ratio is more female-biased than expected, which we attribute to the sampling biased towards one male units and limited sampling of bachelor male units. Moreover, there is no suggestion that the heavy traffic road through the reserve might block movement of monkeys. The results of this study indicate genetic assessments based on a noninvasive sampling method can provide useful information regarding populations of elusive primates.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.