High flexibility in diet and ranging patterns in two golden monkey (Cercopithecus mitis kandti) populations in Rwanda

Many primates exhibit behavioral flexibility which allows them to adapt to environmental change and different habitat types. The golden monkey (Cercopithecus mitis kandti) is a little-studied endangered primate subspecies endemic to the Virunga massif and the Gishwati forest in central Africa. In the Virunga massif, golden monkeys are mainly found in the bamboo forest, while in the Gishwati forest they live in mixed tropical montane forest. Here we describe and compare the diet of golden monkeys in both fragments. Over 24 consecutive months from January 2017 we used scan sampling to record feeding and ranging behavior of two Virunga groups and one Gishwati group totaling ca. 240 individuals. We also examined the phenology of bamboo and fruit trees, key seasonal food plant species for the monkeys. Golden monkeys fed on more than 100 plant species. The Virunga groups were mostly folivorous (between 72.8% and 87.16% of the diet) and fed mostly on young bamboo leaves and bamboo shoots, while 48.69% of the diet of the Gishwati group consisted of fruit from 22 different tree and shrub species. Bamboo shoots and fruit are seasonally available foods and were consumed regularly throughout the period when they were available. Despite being the smallest of the three study groups, the Gishwati group had a larger home range area (150.07 ha) compared to both Virunga groups (25.24 and 91.3 ha), likely driven by the differences in availability and distribution of fruit and bamboo in the habitats. Like other blue monkey subspecies, golden monkeys appear to have a flexible dietary strategy enabling them to adjust diet and ranging behavior to local habitats and available food resources. Additional studies and continuing conservation efforts are needed to better understand how variation in feeding and ranging ecology affects reproduction, population growth, and carrying capacity.     

Diet,Activity Patterns,and Ranging Ecology of the Bale Monkey (<Emphasis Type="BoldItalic">Chlorocebus djamdjamensis</Emphasis>) in Odobullu Forest,Ethiopia

Bale monkeys (Chlorocebus djamdjamensis) are little-known primates endemic to the forests of the Bale Massif and Hagere Selam regions of Ethiopia. From August 2007 to May 2008, we conducted the first ever study of the species’ behavior and ecology, focusing in particular on its diet, activity patterns, and ranging ecology in the Odobullu Forest. We studied 2 neighboring groups (group A: 55–60 members; group B: 46–50 members) and conducted behavioral scan samples on the first 2–5 individuals sighted at 15-min intervals. Feeding accounted for 65.7% of the activity budget, followed by moving (14.4%), resting (10.7%), social (7.1%), and other behaviors (2.4%). Overall diet during the study was dominated by young leaves (80.2%), though subjects also ate fruits (9.6%), flowers (3.1%), animal prey (2.3%), shoots (1.5%), stems (1.4%), mature leaves (1.1%), and roots (0.9%). Bale monkeys consumed only 11 plant species; of these, the top 5 species accounted for 94.3% of their diet. The top food item, bamboo (Arundinaria alpina), was responsible for a remarkable 76.7% of their diet, with most (95.2%) of the bamboo consumption consisting of young leaves. Mean daily path length for the study groups was 928 m and mean (100% minimum convex polygon) home range size was 15.2 ha. Though we are cautious in drawing conclusions from only 2 groups, the larger group traveled further per day and occupied a larger home range, patterns suggesting scramble competition may be occurring in Bale monkey groups at Odobullu. The dietary specialization of Bale monkeys on bamboo makes them unique among Chlorocebus spp. and suggests an intriguing ecological convergence with the golden monkeys (Cercopithecus mitis kandti) of Uganda and bamboo lemurs (Hapalemur spp.) of Madagascar. Their narrow ecological niche, limited geographic distribution, and bamboo harvesting by local people for commercial purposes place Bale monkeys at risk of extinction. To ensure the long-term survival of Bale monkeys, appropriate management action should be taken to conserve the species and the bamboo forests upon which it depends.     

The value of flagship and umbrella species for restoration and sustainable development: Bale monkeys and bamboo forest in Ethiopia

Forest loss and degradation are the most significant threats to terrestrial biodiversity in the tropics. Promoting flagship or umbrella species is a strategy that can be used to conserve intact forests and restore degraded ecosystems, conserve biodiversity, and achieve sustainable development goals. The Bale monkey (Chlorocebus djamdjamensis) is an arboreal, forest-dwelling, threatened primate restricted to a small range in the southern Ethiopian Highlands, which relies mostly on a single species of bamboo (Arundinaria alpina) and prefers bamboo forest habitat. Most of the Bale monkey’s range lies outside protected areas and most of its historical bamboo forest habitat is degraded or destroyed. The conservation of Bale monkeys and bamboo is highly inter-dependent; however, the value of using the Bale monkey as a flagship or umbrella species for forest restoration has not been evaluated. Here we use geographic range overlap and geospatial modeling to evaluate Bale monkeys as a flagship and/or umbrella species. We also assess if conservation intervention on behalf of Bale monkeys can help restore bamboo forest, while simultaneously providing a wide range of socioeconomic and environmental benefits. We found that Bale monkeys share their range with 52 endemic and/or threatened vertebrate species and at least 9 endemic and/or threatened plant species. Our results show that Bale monkeys meet both the flagship and umbrella species criteria to restore bamboo forest and conserve threatened co-occurring species. Since bamboo is fast-growing and can be harvested every year, we suggest that a science-based sustainable harvest and management regime for bamboo would help to improve the livelihood of both the local community and Ethiopians in general without significantly affecting the long-term survival of Bale monkeys and regional biodiversity. Further, a conservation management strategy protecting and restoring bamboo forest has the potential to achieve at least six of the 17 United Nations Sustainable Development Goals.     

Modelling changes in the distribution of the critical food resources of a specialist folivore in response to climate change

Aim An important consideration when planning to conserve a species under climate change is to understand how the distribution of its food resources may also contract or shift under those same climatic conditions. Here, we use a case study to demonstrate a spatial conservation planning approach to inform decisions about where, under climate change, to protect and restore critical food and habitat resources for highly specialized species. Location Eastern Australia. Methods We developed fitted models for the koala (Phascolarctos cinereus) and five of its key eucalypt food trees using the maximum entropy algorithm available in Maxent. We then projected these models using a range of IPCC A1FI climate change scenarios and identified areas with a higher probability of occurrence. We calculated where the koala and its food trees may co‐occur under future climate change. Results The koala and its food trees experienced significant range contractions as climate change progressed, sometimes to regions outside their current distributions. The inland species Eucalyptus camaldulensis and Eucalyptus coolabah contracted from the more arid interior, which is outside the koala range, but persisted in the eastern regions of the koala’s range, while Eucalyptus viminalis, Eucalyptus populnea and Eucalyptus tereticornis contracted eastwards and southwards, with a fragmented distribution. The highest probabilities of overlap between koalas and their food trees were identified in fragmented coastal and southern regions of the koala’s current range. Main conclusions The application of a robust species distribution modelling decision support tool identified important changes, under climate change, in the distribution of a specialist species and its key food trees. These distributions did not change in complete synergy and therefore areas of overlap varied, depending on the food tree species modelled. This is of particular importance in a conservation planning context, when considering targeted protection and restoration of species‐specific habitat resources.     

Status and ecology of the golden monkey (Cercopithecus mitis kandti) in Mgahinga Gorilla National Park, Uganda

Given the degree to which tropical ecosystems are currently being disturbed by human activities, it is essential to set priorities for conservation and thus it becomes important to consider how best to set these priorities. From this perspective, this study provides the first detailed investigations of Cercopithecus mitis kandti, the golden monkey, focusing on the population in Mgahinga Gorilla National Park (MGNP), Uganda. Specifically, we (1) establish the current status of the golden monkey in terms of population size and distribution within the park in relation to vegetation types and altitude, and (2) investigate the golden monkey's feeding ecology. A total of 67 censuses of 4+ km transects were conducted along a cumulative distance of 299 km and 132 social groups were encountered. Densities were estimated to have increased by 1.6 times since a census 8 years ago, and the total population in the park is estimated to be between 3164 and 5059 individuals. The average size of golden monkey groups in MGNP is 30 individuals (range 3–62). This is similar to that of other subspecies in neighbouring forests. In contrast, the census conducted 8 years before estimated average group size to be eight individuals. Golden monkeys were observed to eat 21 plant species and they were inferred to eat an additional eleven from signs left behind and reports. Both study groups relied upon leaves (primarily young leaves), fruits and invertebrates for food, but the amount of time they fed on these different types of foods varied between the groups. Given the apparent increase in density since the census 8 years ago, the golden monkeys of MGNP appear to be doing well. However, given the number of snares and the extent of illegal extraction of bamboo found during the census, conservation efforts should be increased.     

Extension of the Geographical Range of White-browed Titi Monkeys (<Emphasis Type="BoldItalic">Callicebus discolor</Emphasis>) and Evidence for Sympatry with San Martin Titi Monkeys (<Emphasis Type="BoldItalic">Callicebus oenanthe</Emphasis>)

White-browed titi monkeys (Callicebus discolor) have one of the largest distribution ranges of all titi monkey species, occurring from central Peru to southern Colombia. During a long-term study on the distribution of titi monkeys and other primates in Peru, we conducted extensive surveys in the San Martin Department of northeastern Peru. We encountered Callicebus discolor at the left bank of the Huallaga River, where the species most probably lives in sympatry with endemic San Martin titi monkeys (Callicebus oenanthe). Our study reveals an important extension of its formerly known distribution range. Massive deforestation activities in the region make studies on the habitat preferences of both species difficult, as most titi monkeys are confined to the remaining small remnants of the original forest. Urgent conservation measures are necessary to preserve the last lowland forests of San Martin.     

Newly discovered Bale monkey populations in forest fragments in southern Ethiopia: evidence of crop raiding, hybridization with grivets, and other conservation threats

Until recently, the Bale monkey (Chlorocebus djamdjamensis), an arboreal primate endemic to the southern Ethiopian highlands, remained virtually unstudied, and its distribution pattern inadequately documented. To broaden our knowledge of the species' distribution and abundance, we carried out interviews with local people and total count surveys for Bale monkeys across 67 fragmented forest sites in human-dominated landscapes in the Oromia and Southern Nations, Nationalities, and People's Regions, Ethiopia. From January 2010 to May 2011, we discovered 26 new Bale monkey populations inhabiting forest fragments at elevations ranging from 2,355 to 3,204 m asl. Across these populations, we recorded 37 groups ranging in size from 9 to 29 individuals (Mean = 19.5, SD = 4.5), for a total of 722 individuals. Black-and-white colobus monkeys (Colobus guereza) were sympatric with Bale monkeys at all sites, while grivet monkeys (Chlorocebus aethiops) were found only at sites where Bale monkeys did not occur. All of the newly discovered Bale monkey sites once contained bamboo forest, though at 35% of the sites bamboo forest had been eliminated during the past two decades. The persistence of Bale monkeys at fragmented sites lacking bamboo suggests greater habitat flexibility for the species than previously thought, though the long-term viability of populations both with and without bamboo remains uncertain. Human hunting in response to crop raiding, a behavior the monkeys engaged in at all sites, represents a major threat facing the newly discovered Bale monkey populations. Furthermore, despite their current lack of sympatry, apparently hybrid individuals between Bale monkeys and grivets were noted at three sites, posing yet another potential obstacle to Bale monkey conservation. Community conservation programs aimed at (1) protecting remaining habitat fragments, (2) planting bamboo and trees within and between fragments, and (3) reducing crop raiding represent the only hope for survival of the newly discovered Bale monkey populations.     

Winter Feeding Tree Choice in Sichuan Snub-Nosed Monkeys (Rhinopithecus roxellanae) in Shennongjia Nature Reserve,China

We investigated patterns of winter feeding tree choice in 4 groups of Sichuan snub-nosed monkeys (Rhinopithecus roxellanae) in Shennongjia Nature Reserve, China. We collected data during 2 winters from 1998 to 2000. The monkeys used mature forest, young forest and shrub forest, but not grassland. Groups used tree species in a significantly nonrandom pattern. There was a similar composition of preferred tree species between different habitats for each group and among the same habitat types for different groups. They preferred Abies fargesii, Pinus armandii and Salix walliciana for foraging. The 3 species occur in varying degrees of abundance in different habitats and were used differently by the 4 groups. The difference is probably due to interhabitat differences in availability of tree species, in addition to microclimate. The mean circumference of a tree had little effect on its preference score, but preferred species tend to be larger. A Wilcoxon signed-rank test indicated that the percentage of trees used and average number of feeding bites per tree is significantly greater for larger trees. For all trees in a given habitat, the percentage of trees used and average number of bites per tree have a significant positive correlation with average tree circumference. Our results indicate that Rhinopithecus roxellanae prefer to feed in large trees more than small trees in a given habitat, thereby preferring mature forest habitat. There is also a group-size effect; larger groups used higher-quality habitats than those of smaller groups. Both tree species and size are the major determinants of feeding choice, but tree species is more important than tree size. Our results have at least three implications for winter habitat conservation of Sichuan snub-nosed monkeys. Conservation efforts should be focused on mature forest because it is better habitat at Rhinopithecus than young forest, as long as the same tree species are present. Secondly, Pinus armandii, Abies fargesii and Salix walliciana should be conserved as top priority in forest communities. Third, the largest trees in each habitat should be given greatest possible protection.     

基于微卫星DNA的神农架川金丝猴遗传结构研究

川金丝猴(Rhinopithecus roxellana)是我国特有珍稀濒危物种,了解其种群遗传结构和关键影响因素,对该物种的保护具有重要意义。以我国分布最东端的湖北神农架川金丝猴种群为研究对象,基于非损伤性DNA技术和微卫星DNA遗传标记等分子生物学方法及景观遗传参数,探讨了神农架川金丝猴的遗传多样性和遗传结构,旨在为川金丝猴的研究及川金丝猴种群的可持续发展提供理论基础。利用12个多态性微卫星位点,在455份川金丝猴粪便样品中,共检测到62个微卫星等位基因;共鉴定出316个不同川金丝猴个体;种群的平均期望杂合度、平均观察杂合度和多态性信息含量分别为0.626、0.559和0.650;群体间的Nei's遗传距离为0.046—0.139,分化系数为0.015—0.046。结果表明与其他地区川金丝猴种群相比,神农架川金丝猴种群具有较低的遗传多样性水平,种群内部存在遗传分化趋势;结合景观参数分析表明地理距离不是影响神农架川金丝猴群体间遗传距离的主要因素,而生境中的灌丛和草地以及人类活动干扰可能是影响川金丝猴遗传交流的主要因素。     

Terrestriality and tree stratum use in a group of Sichuan snub-nosed monkeys

Morphological characters allow the Sichuan snub-nosed monkey (Rhinopithecus roxellana) to use multiple tree levels, but very few studies have quantified the terrestriality and tree stratum use of the species. I investigated the terrestriality and tree stratum use in a group of the monkeys from July 2003 to September 2004 (except February) in the Qianjiaping area of Shennongjia Nature Reserve, China. I collected data on the vertical position of individual monkeys in forest in relation to behavior types, diet, age/sex classes, vegetation types, tree height, and distribution of predators. The monkeys were much more arboreal than they were thought to be. They spent 97.1% of their time in trees (n=21,234 records) and 2.9% on the ground, and mainly used the middle (74.4%) and upper strata (17.4%). The monkeys displayed all behavioral types except searching in the middle and upper strata. The percentage of use of a stratum (except the low stratum) varied among months, and there was a difference in the percentage of use of a stratum among age/sex classes and between vegetation types. Approximately 94.2% of trees used by the monkeys were >6 m tall. They mainly fed on lichens, young leaves, mature leaves, flowers, fruits or seeds, and buds in the middle and upper strata, bark in the low and middle strata and herbs on the ground. Wolf (Canis lupus), leopard (Panthera pardus), and golden eagle (Aquila chrysaetos) are predators threatening the survival of individual monkeys in the study site. The results suggested that the seasonal vertical distribution of food items eaten in forest, predators, and vegetation types had important effects on the terrestriality and tree stratum use of the monkeys.     

A preliminary assessment of large mammal and bird use of different habitats in Bwindi Impenetrable National Park

Understanding species distributions, habitat requirements, and population trends is helpful for implementing effective conservation. But expense often prevents such evaluations. Here, we present a preliminary assessment for a low‐cost method – road‐side observations – to see how effective it can be. The bamboo zone of Bwindi Impenetrable National Park is restricted, covering 0.3% of park area yet is poorly known. Our study evaluates the use of the bamboo zone and surrounding forest by species of large mammals and large ground birds. Data were collected while driving a road section running through this zone. During 416 trips, seven species of mammal and one bird were recorded. Distributions for most species were significantly nonrandom in both space (P < 0.02) and time (Hour of day: P < 0.040; Month: P < 0.0001) for all species but black‐fronted duikers and blue monkeys for which 0.085 > P > 0.050 for month. Of the species observed, francolins were more frequently seen in the zone of visible bamboo than the nonbamboo zone (P = 0.002). Black‐and‐white colobus, L’Hoest’s monkey, and jackals were more common in nonbamboo forest (P ≤ 0.05). Road sightings have potential for low‐cost habitat use assessments and monitoring.     

Competition and habitat selection in Namib desert tenebrionid beetles

Summary We tested whether intra- and interspecific competition could affect habitat selection in the two most abundant tenebrionid beetles,Physadesmia globosa andOnymacris rugatipennis, in a dry riverbed in the Namib desert. The spatial distributions of these beetles at the microhabitat scale were negatively correlated. We performed a removal experiment, progressively removing first 25% and then a further 25% of the population of the most abundant species,P. globosa, under the trees where most of the preferred food of both species is concentrated. There was no response ofO. rugatipennis to this removal in the tree habitat. In the open, barely-vegetated habitat where mostO. rugatipennis are found, the number of this species caught in pitfall traps increased following both removals and decreased followingP. globosa replacement under the trees. It appears that intraspecific competition forces someP. globosa to occupy the open habitat. Interspecific competition betweenP. globosa andO. rugatipennis in the open habitat reduces the number ofO. rugatipennis that can co-exist withP. globosa there. Removal ofP. globosa under the trees allows conspecifics in the open habitat to move under the trees, releasingO. rugatipennis in the open habitat from competition. This then results in an increase in the numbers ofO. rugatipennis in the open habitat as a result of immigration from neighbouring areas. We found that differences in foraging efficiency, measured as giving-up times in artificial food patches, create a likely mechanism of co-existence that explains the distinct preferences of these two species for tree and open habitats.     

Feeding ecology of the proboscis monkey (Nasalis larvatus)

Proboscis monkey (Nasalis larvatus) feeding behavior and ecology were studied at the Natai Lengkuas Station, Tanjung Puting National Park, Kalimantan Tengah, Indonesia. Data on feeding behavior were collected using scan sampling during group follows. Three vegetational plots containing 1,732 trees were established and monitored monthly for changes in fruit, flower, and young leaf production. Basal area and canopy cover were calculated and used in estimating food abundance. Proboscis monkeys were found to be folivore/frugivores, specializing in seed consumption. At least 55 different plant species were used as food sources, with a marked preference for Eugenia sp. 3/4,Ganua motleyana and Lophopetalum javanicum. These tree species were among the most frequent and most dominant. However, proboscis monkeys were selective feeders; use of tree species as food sources was not based simply on relative density. During times of low food abundance and/or availability proboscis monkeys switched dietary strategies and increased dietary diversity. The average total home range was estimated to be 130.3 ha, with an average group density of 5.2 groups per km². The average biomass per km² was estimated to be 499.5 kg. Given their high biomass and predilection for consuming seeds of dominant species, proboscis monkeys may help to maintain and increase vegetational diversity.     

Effects of habitat disturbance and food supply on population densities of three primate species in the Kakamega Forest, Kenya

While habitat disturbance and food availability are major factors thought to determine the abundance of primates, evidence for their importance is uneven. We assessed the effects of these factors on three monkey species, guerezas ( Colobus guereza ) , blue monkeys ( Cercopithecus mitis ) and redtails ( Cercopithecus ascanius ), in four areas of the Kakamega Forest, Kenya. Group densities of guerezas and blue monkeys were higher in areas where disturbance levels were also higher. Food availability measured as basal area density of food trees did not correlate significantly with the group densities of any of the three monkeys. The diversity of food trees, another potential measure of food abundance did, however, correlate with group densities of guerezas and blue monkeys suggesting that food availability may positively influence monkey density, and may sometimes increase with disturbance. Group densities of redtails did not correlate with any habitat variable examined, suggesting that factors other than those we considered may have influenced the abundance of this species particularly.     

Use of leaf resources by howling monkeys (Alouatta palliata) and leaf-cutting ants (Atta cephalotes) in the tropical rain forest of Los Tuxtlas,Mexico

Use of leaf resources by a troop of howling monkeys and two colonies of leaf cutting ants was studied for an annual cycle in the rain forest of Los Tuxtlas, Mexico. Howling monkeys spent half their annual foraging time feeding on leaves; leaf-cutting ants spent at least 80% of their recorded foraging time harvesting leaves. Both herbivores preferred young leaves over nature ones, and chemical analysis showed that the protein: fibre ratio of the leaves used was correlated with these preferences. Howling monkeys used 34 tree species as leaf sources. Leaf-cutting ants used 40 plant species of which 38 were trees. Eighteen species used by Alouatta were also used by Atta; species of Moraceae and Lauraceae were among the most important in their foraging preferences. The plant species used by monkeys and ants occurred at low densities (? 4.0 ind/ha). The seasonal production of leaves, the high density of leaf-cutting ant colonies at the study site, and the high amounts of young foliage harvested by the ants from tree species, and individual trees used by howling monkeys as sources of young leaves suggest that the foraging activities of Atta may represent a significant pressure upon leaf resources available to Alouatta.     

Red panda fine‐scale habitat selection along a Central Himalayan longitudinal gradient

Red panda Ailurus fulgens, an endangered habitat specialist, inhabits a narrow distribution range in bamboo abundance forests along mountain slopes in the Himalaya and Hengduan Mountains. However, their habitat use may be different in places with different longitudinal environmental gradients, climatic regimes, and microclimate. This study aimed to determine the habitat variables affecting red panda distribution across different longitudinal gradients through a multivariate analysis. We studied habitat selection patterns along the longitudinal gradient in Nepal's Himalaya which is grouped into the eastern, central, and western complexes. We collected data on red panda presence and habitat variables (e.g., tree richness, canopy cover, bamboo abundance, water availability, tree diameter, tree height) by surveys along transects throughout the species’ potential range. We used a multimodal inference approach with a generalized linear model to test the relative importance of environmental variables. Although the study showed that bamboo abundance had a major influence, habitat selection was different across longitudinal zones. Both canopy cover and species richness were unimportant in eastern Nepal, but their influence increased progressively toward the west. Conversely, tree height showed a decreasing influence on habitat selection from Eastern to Western Nepal. Red panda's habitat selection revealed in this study corresponds to the uneven distribution of vegetation assemblages and the dry climatic gradient along the eastern‐western Himalayas which could be related to a need to conserve energy and thermoregulate. This study has further highlighted the need of importance of bamboo conservation and site‐specific conservation planning to ensure long‐term red panda conservation.     

Habitat use by a primate community in a lowland dipterocarp forest in Danum Valley,Borneo

Knowledge of niche partitioning with respect to habitat is indispensable to understand the mechanism of coexistence of multiple species. Among primates, however, data are still deficient because repeated survey for a sufficiently long time, covering seasonal changes over a large area, is the only way to clarify habitat segregation within a seasonally fluctuating environment. Southeast Asia is particularly interesting because of the supra-annual, highly unpredictable seasonality in fruiting known as mast fruiting. We conducted repeated route census, habitat monitoring, and group tracking for 25 months in two study sites (ca. 10 km apart) in the largely primary lowland dipterocarp forest of the Danum Valley Conservation Area, eastern Sabah, northern Borneo, Malaysia. The five species of diurnal primates (Bornean orangutan Pongo pygmaeus, Müeller's gibbon Hylobates muelleri, red leaf monkey Presbytis rubicunda, long-tailed macaque Macaca fascicularis, and southern pig-tailed macaque M. nemestrina) did not show horizontal spatial segregation. Red leaf monkeys showed preferences for places with short tree height, but their distribution was not confined to such places. In response to the fruiting peak observed once during the study period, orangutans increased their numbers simultaneously in the two study sites. The average tree height used by the five species was different, but their range overlapped substantially. Compared with other primate communities, the lack of horizontal spatial segregation and the suggested long-distance movement of orangutans seem to be unique characteristics in Borneo, although the use of different forest strata is a widespread phenomenon among primate communities throughout the world.     

川金丝猴食谱的地域性差异比较

对不同地区川金丝猴食物组成的比较有助于了解其对不同生境食物供应的适应性。本研究通过对陕西川金丝猴猴群食谱的长期记录,并汇集了国内对四川-甘肃和湖北的川金丝猴食性研究结果,集成了这三个地理种群川金丝猴各自的地域性食谱,共计有136 种植物(隶属35 科)被该物种作为采食对象。对来自这三个不同区域(陕西、四川-甘肃、湖北)的川金丝猴食谱组成的比较,发现有近半数的植物是三个地理种群共同的采食对象,但其食谱组成差异明显。这可能源于各地植物本身的多样性差异,及不同地理种群对各种食物采食偏好的不同所致。对其相关聚类分析结果显示,陕西和湖北的猴群在食谱组成上相近,但四川-甘肃的猴群与前两个地区猴群的食谱组成差异极大。然而湖北和四川-甘肃种群在食物的选择上采用了近乎相同的偏好倾向,而陕西的猴群与它们明显不同。我们初步分析认为造成食谱组成和采食偏好差异的原因可能是各地理种群活动地海拔带重叠度不同、森林类型不同、它们在不同林型中活动的时间分配不一。很明显,就我们目前所掌握的有关川金丝猴食谱组成来看,该物种不应该仅仅被认为是一个叶食性灵长类动物,而应该是一个泛化采食者。     

Dietary Profile of <Emphasis Type="Italic">Rhinopithecus bieti</Emphasis> and Its Socioecological Implications

To enhance our understanding of dietary adaptations and socioecological correlates in colobines, we conducted a 20-mo study of a wild group of Rhinopithecus bieti (Yunnan snub-nosed monkeys) in the montane Samage Forest. This forest supports a patchwork of evergreen broadleaved, evergreen coniferous, and mixed deciduous broadleaved/coniferous forest assemblages with a total of 80 tree species in 23 families. The most common plant families by basal area are the predominantly evergreen Pinaceae and Fagaceae, comprising 69% of the total tree biomass. Previous work has shown that lichens formed a consistent component in the monkeys’ diet year-round (67%), seasonally complemented with fruits and young leaves. Our study showed that although the majority of the diet was provided by 6 plant genera (Acanthopanax, Sorbus, Acer, Fargesia, Pterocarya, and Cornus), the monkeys fed on 94 plant species and on 150 specific food items. The subjects expressed high selectivity for uncommon angiosperm tree species. The average number of plant species used per month was 16. Dietary diversity varied seasonally, being lowest during the winter and rising dramatically in the spring. The monkeys consumed bamboo shoots in the summer and bamboo leaves throughout the year. The monkeys also foraged on terrestrial herbs and mushrooms, dug up tubers, and consumed the flesh of a mammal (flying squirrel). We also provide a preliminary evaluation of feeding competition in Rhinopithecus bieti and find that the high selectivity for uncommon seasonal plant food items distributed in clumped patches might create the potential for food competition. The finding is corroborated by observations that the subjects occasionally depleted leafy food patches and stayed at a greater distance from neighboring conspecifics while feeding than while resting. Key findings of this work are that Yunnan snub-nosed monkeys have a much more species-rich plant diet than was previously believed and are probably subject to moderate feeding competition.     

Resorption Efficiency of Four Cations in Different Tree Species in a Subtropical Common Garden

High rainfall in subtropical regions can leach cation elements from ecosystems, which may limit plant growth. Plants often develop efficient resorption patterns to recycle elements, but there is relatively little available information on this topic. In February 2012, a common garden was established in a subtropical forest by planting dominant trees from the area. Green and senescent leaves were sampled from 11 tree species. The concentrations of potassium (K), calcium (Ca), sodium (Na) and magnesium (Mg) were determined, and the resorption efficiencies were calculated. The results showed significant K, Na and Mg resorption in most of the investigated tree species, while Ca mainly displayed accumulation. Evergreen coniferous and evergreen broad-leaved trees (such as Cunninghamia lanceolata, Pinus massoniana, Cinnamomum camphora, and Michelia macclurei) exhibited relatively higher resorption efficiencies of K (39.0%–87.5%) and Na (18.3%–50.2%) than deciduous broad-leaved trees. Higher Mg resorption efficiencies (>50%) were detected in Liriodendron chinense, C. lanceolata and P. massoniana than in other trees. Overall, evergreen coniferous and evergreen broad-leaved trees could show higher cation resorption than deciduous broad-leaved trees. K and Mg resorption efficiencies and Ca accumulation decrease with increasing nutrient concentrations in green leaves. Our results emphasize that nutrient resorption patterns largely depend on elements and plant functions, which provides new insights into the nutrient use strategies of subtropical plants and a reference for the selection of suitable tree species in this region.