Investment in science can mitigate the negative impacts of land use on declining primate populations.

Changes in land use and the conversion of natural forests to agricultural fields and cattle pastures are threatening the survival of many species of wild animals, including nonhuman primates. Given its almost 1.4 billion people, China faces a difficult challenge in balancing economic development, human well-being, environmental protection, and animal conservation. We examined the effects of poverty, anthropogenic land use (cropland and pasture/grazing), human population growth, government investment in science and public attention to primates during the period from the 1980s to 2015 on primate population persistence in China. We analyzed these data using generalized mixed-effects models, structural equation models (SEM) and random forests (a machine learning technique). We found that 16 of 21 (76%) primate species in China, for which data are available, have experienced a population decline over the past 35 years. Factors contributing most to primate population decline included human poverty and the conversion of natural habitat to cropland. In contrast, the five species of primates that were characterized by recent population increases were the subjects of substantial government research funding and their remaining distribution occurs principally in protected areas (PAs). We argue that increased funding for research, the establishment and expansion of PAs, a national policy focused on reducing poverty, and educational programs designed to inform and encourage local people to participate in scientific investigation and wildlife protection, can mitigate the negative impacts of historical patterns of land conversion on primate population survival in China.

Impact of cost distance and habitat fragmentation on the daily path length of Rhinopithecus bieti.

An understanding of primate movement patterns in response to natural and anthropogenically induced changes in habitat heterogeneity, food availability, and plant species distribution is essential for developing effective management and conservation programs. Therefore, from July 2013 to June 2014, we examined the effects of landscape configuration on the ranging behavior (daily path length, DPL) of the Endangered Yunnan snub-nosed monkey (Rhinopithecus bieti) in the Baimaxueshan National Nature Reserve (27°34'N, 99°17'E) in Gehuaqing, China. Given the extreme difficulties in following the study group across high altitude mountainous terrain across an elevation of 2,500-4,000 m, we were only able to collect DPL using 3-4 GPS points per day on 21 individual days. We found that R. bieti traveled the shortest DPL in winter (1,141.31 m), followed by spring (2,034.06 m) and autumn (2,131.19 m). The cost distance, a statistical tool designed to estimate the difficulty of a species moving across its distributional range, was lowest in autumn (205.47), followed by spring (225.93) and winter (432.59) (one-way ANOVA: F = 3.852, P = 0.026, df = 2). The habitat fragmentation index (HFI), which measures the density of forest patches, indicated areas visited in the winter were more fragmented (HFI = 2.16) compared to spring (HFI = 1.83) or autumn (HFI = 1.3). Although our results should be considered preliminary, they suggest that both the availability of suitable travel routes and habitat fragmentation, driven by high-intensity human disturbance, constrain the movement of R. bieti. We found that undisturbed areas of the bands' range contained a high density of lichens, which represent a nutritious and abundant and year-round food source for Yunnan snub-nosed monkeys. In order to protect this Endangered species, we recommend that researchers construct detailed maps of landscape heterogeneity, particularly habitat connectivity, forest fragmentation, and seasonal variation in the location of major food patches in order to better understand and mitigate the effects of seasonal habitat change on patterns of R. bieti habitat utilization and population viability.

[Ecotourism disturbances to non-human primates].

In tandem with economic growth and rising living conditions, ecotourism has increasingly gained popularity among the Chinese public. Non-human primates, as charismatic animals and the closest relatives of human beings, have shown a strong affinity in attracting the general public and raising money, and for that reason a variety of monkey parks, valleys, and islands are becoming increasingly popular in China. Though successful in raising a substantial sum of money for the managing agency of a nature reserve, there may be negative impacts on monkey groups used in ecotourism. Here, to establish effective guards for non-human primates involved in ecotourism, we present a review on tourism disturbance and summarize the negative impacts on behavioral patterns, reproduction, and health condition of animals.

Social structure and group dynamics of the Cao Vit gibbon (Nomascus nasutus) in Bangliang, Jingxi, China.

The Cao Vit gibbon (Nomascus nasutus) was rediscovered in 2002 in Vietnam and then in 2006 in China. This is the only known population with about 110 individuals located along the China-Vietnam border. Little is known about it other than its population size and distribution. We describe the social structure and group dynamics of the Cao Vit gibbons in China based on 2 years of monitoring from 2007 to 2009. Four established study groups at this site consisted of 1 adult male, 2 adult females and 2-6 offspring. Two juveniles in 2 groups disappeared during the research. Four infants were born in 3 groups from November 2008 to February 2009. In 2 of the groups, both adult females had dependent infants. These observations suggest that Cao Vit gibbons live in polygynous groups, contrary to the usual monogamous group with only 1 adult female, but nevertheless similar to the social organization of both N. concolor and N. hainanus. We observed a coordinated dispersal of 1 adult male and 2 large juveniles, and the male formed a pair with a newly arrived female. Our observations support a growing awareness of variability in gibbon social organization.

Fallback foods of temperate-living primates: a case study on snub-nosed monkeys.

Only a few primate species thrive in temperate regions characterized by relatively low temperature, low rainfall, low species diversity, high elevation, and especially an extended season of food scarcity during which they suffer from dietary stress. We present data of a case study of dietary strategies and fallback foods in snub-nosed monkeys (Rhinopithecus bieti) in the Samage Forest, Northwest Yunnan, PRC. The snub-nosed monkeys adjusted intake of plant food items corresponding with changes in the phenology of deciduous trees in the forest and specifically showed a strong preference for young leaves in spring. A non-plant food, lichens (Parmeliaceae), featured prominently in the diet throughout the year (annual representation in the diet was about 67%) and became the dominant food item in winter when palatable plant resources were scarce. Additional highly sought winter foods were frost-resistant fruits and winter buds of deciduous hardwoods. The snub-nosed monkeys' choice of lichens as a staple fallback food is likely because of their spatiotemporal consistency in occurrence, nutritional and energetic properties, and the ease with which they can be harvested. Using lichens is a way to mediate effects of seasonal dearth in palatable plant foods and ultimately a key survival strategy. The snub-nosed monkeys' fallback strategy affects various aspects of their biology, e.g., two- and three-dimensional range use and social organization. The higher abundance of lichens at higher altitudes explains the monkeys' tendency to occupy relatively high altitudes in winter despite the prevailing cold. As to social organization, the wide temporal and spatial availability of lichens strongly reduces the ecological costs of grouping, thus allowing for the formation of "super-groups." Usnea lichens, the snub-nosed monkeys' primary dietary component, are known to be highly susceptible to human-induced environmental changes such as air pollution, and a decline of this critical resource base could have devastating effects on the last remaining populations. Within the order Primates, lichenivory is a rare strategy and only found in a few species or populations inhabiting montane areas, i.e., Macaca sylvanus, Colobus angolensis, and Rhinopithecus roxellana. Other temperate-dwelling primates rely mainly on buds and bark as winter fallback foods.

Social organization of black-and-white snub-nosed monkeys (Rhinopithecus bieti) at Deqin, China.

Data on social organization of two bands of black-and-white snub-nosed monkeys (Rhinopithecus bieti) were collected when the monkeys were crossing an open spot at Nanren and Bamei (northwest of Yunnan, China) using a sampling rule where individuals within one social unit are spatially closer to each other than individuals between social units. The typical pattern of social organization in this sample was multiple adult females (AFs) and their offspring with one adult male (AM) in a one-male unit (OMU), similar to that of many other colobines. In such units, on average one male is associated with 4.0 AFs and 2.5 of their offspring. Moreover, there are multimale/multifemale units and monogamous units besides OMUs. All bisexual units traveled together with at least one all-male unit as a cohesive band. In two bands of monkeys, 87% of AMs in bisexual units were within OMUs, 7.8% within monogamous units and 5.2% within multimale, multifemale units. In the Bamei band, 6.7% of AMs were in the all-male unit. The size of OMUs in the Nanren band was larger than that of the Bamei band, with more AFs and juveniles, which may be related to better conservation in the Nanren band's habitat. For the Nanren band, the average number of AFs in OMUs varied across time, increasing from 4.3 in 1994 to 5.1 in 2001, and then decreasing to 3.8 in 2005. This article suggests three possible explanations for this variation, but more data are needed for these hypotheses to be tested.