Data on sleeping sites of a group of black-and-white snub-nosed monkeys Rhinopithecus bieti (Colobinae, Primates) were collected between April-July and September-December 2001 to try to determine the factors affecting site selection at Nanren (99104 0 E, 28134 0 N, Baima Snow Mountain, China). Sleeping trees were tall emergents (27.5 AE 3.2 m) with large diameter at breast height (57.9 AE 16.9 cm) and broad crown diameters (6.3 AE 1.4 m), and significantly larger than other trees. The use of large sleeping trees could provide effective shelters from attacks of terrestrial and aerial predators, heavy snow and rain. Sleeping sites were changed nightly and located at significantly lower altitudes in winter months than in other seasons, which might be a thermoregulatory adaptation or related to snow covering. Such sites tended to be at the middle of sun-oriented slopes, possibly trading off predator avoidance and foraging efficiency.
Aim Forest fragmentation is often accompanied by an increase in hunting intensity. Both factors are known drivers of species extirpations, but understanding of their independent effects is poor. Our goal was to partition the effects of hunting and fragmentation on bird species extirpations and to identify bird traits that make species more vulnerable to these two stressors.
Location Menglun, Yunnan, SW ChinaMethods We studied the landscape within 10 km radius of Menglun town, where forests have become highly fragmented by monoculture rubber plantations. We compiled data on birds recorded between 1954 and 1983 before forest loss and compared it with a checklist prepared between 2011 and 2014. We used countryside and matrix-calibrated species-area models (SAMs) to estimate the observed slope of forest bird extirpations in Menglun and compared it with the slope expected in the absence of hunting. We also investigated six ecological traits to determine those that best explained bird extirpation probability (EP).
ResultsWe found that 34% of the bird fauna had been extirpated from the study landscape, and the estimated slopes of countryside and matrix-calibrated SAMs for forest birds were around 1.4 and 1.7 times higher, respectively, than the 0.35 expected without hunting. Bird EP was strongly associated with size, and understorey insectivores that are known to be susceptible to fragmentation were less susceptible to hunting than frugivores. Given evidence of past and present hunting activity in the area, and the lack of support for alternative explanations, we suggest that hunting increased forest bird extirpations by around 1.3-to 1.6-fold.Conclusions This study highlights the importance of using species-area relationships to separate area effects from the impacts of hunting. Our results suggest that hunting substantially increases species extirpations in tropical fragmented landscapes and conservation interventions that only target deforestation will therefore be inadequate.
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