Resource Availability and Habitat Quality Drive Time-Lag Effects in High-Altitude Ungulate Distribution.

Climate change has affected the geographic distribution of many species and numerous endemic species with narrow distribution ranges on the Qinghai-Tibetan Plateau of China, one of the biodiversity hotspots and critical eco-regions in the world. Altun Mountain National Nature Reserve is one of the most important refuges for the flagship species and threatened endemic ungulates, Tibetan antelope (Pantholops hodgsoni), wild Tibetan donkey (Equus kiang), and wild yak (Bos mutus). We surveyed the distribution of these three species and their forage plants in the nature reserve between 2012 and 2013. Using the Maxent model, we projected the potential distribution of the Tibetan antelope, wild Tibetan donkey, and wild yak and their forage plants based on the four representative concentration pathways set by the IPCC Fifth Assessment Report for 2070. We generated 36 future model scenarios to assess and reduce the model uncertainties. We found that projected food availability associated with climate niche would be more realistic for ungulates distribution projections under climate change. Our results demonstrated that future climate change would greatly change the habitats of three threatened endemic ungulates and their forage plants. The ranges of climate niche projected for the Tibetan antelope, wild Tibetan donkey, and wild yak would be reduced by 44, 7, and 20%, respectively, with future climate change under representative concentration pathways 2.6 scenario. Among them, the ranges of Tibetan antelope and wild Tibetan donkey would reduce even more under warmer scenarios, but wild yak would be opposite. The projected distribution ranges of forage plants reduced with the climate change in the future. The combined effects of shifting climate niche and food resources would lead to the reduction of habitats for Tibetan antelope, wild Tibetan donkey, and wild yak by 82, 34, and 30% under representative concentration pathways 2.6. However, conditions would be worse for Tibetan antelope and wild Tibetan donkey but better for wild yak under other scenarios. We suggested that future conservation efforts should be focused on improving habitat quality (including food availability) and finding alternative habitats for the three ungulates especially Tibetan antelope and wild Tibetan donkey.

阿尔金山自然保护区基于野牦牛、藏野驴、藏羚羊适宜栖息地的生态容量估测

Ungulates are essential for maintaining the health of grassland ecosystems on the Tibetan plateau. Increased livestock grazing has caused competition for food resources, threatening ungulates’ survival. The survival risk of food resources for ungulates can be quantified by the grazing pressure index, which requires accurate grassland carrying capacity. Previous research on the grazing pressure index has rarely taken into account the influence of wild ungulates, mainly due to the lack of precise spatial data on their quantity. In this study, we conducted field investigations to construct high-resolution spatial distributions for the four endemic ungulates on the Tibetan plateau. By factoring in the grazing consumption of these ungulates, we recalculated the grassland carrying capacity to obtain the grazing pressure index, which allowed us to assess the survival risks for each species. The results show: (1) Quantity estimates for Tibetan antelope (Pantholops hodgsonii), Tibetan wild donkey (Equus kiang), Tibetan gazelle (Procapra picticaudata), and wild yak (Bos mutus) of the Tibetan plateau are 24.57 × 104, 17.93 × 104, 7.16 × 104, and 1.88 × 104, respectively; they mainly distributed in the northern and western regions of the Tibetan plateau. (2) The grassland carrying capacity of the Tibetan plateau is 69.98 million sheep units, with ungulate grazing accounting for 5% of forage utilization. Alpine meadow and alpine steppe exhibit the highest grassland carrying capacity. (3) The grazing pressure index on the Tibetan plateau grasslands is 2.23, indicating a heightened grazing pressure in the southern and eastern regions. (4) The habitat survival risk analysis indicates that the high survival risk (the grazing pressure index exceeds 1.2) areas for the four ungulate species account for the following proportions of their total habitat areas: Tibetan wild donkeys (49.76%), Tibetan gazelles (47.00%), Tibetan antelopes (40.76%), and wild yaks (34.83%). These high-risk areas are primarily located within alpine meadow and temperate desert steppe. This study provides a quantitative assessment of survival risks for these four ungulate species on the Tibetan plateau grasslands and serves as a valuable reference for ungulate conservation and grassland ecosystem management.

There is an urgent need of understanding the distribution and abundance of the key species, Tibetan wild ass ( Equus kiang ), Tibetan gazelle ( Procapra picticaudata ) and Tibetan antelope ( Pantholops hodgsonii ) in the Three-River-Source National Park, especially after the first national park in China established there. We carried out field surveys in summers from 2014 to 2017 following the distance sampling protocol in the park, covering an area of 538000 km2. The total length of the survey routes is 14597.8 km. We recorded 3711 individuals of Tibetan wild ass, 1187 individuals of Tibetan gazelles, and 423 individuals of Tibetan antelopes. In order to accurately estimate the species abundance, we used species distribution models to quantify the relationship between species accurrences and 22 environmental variables, and predicted the population density in the whole study area. We compared the model prediction and field survey results, and made adjustment accordingly. The estimated abundance of Tibetan wild ass, Tibetan gazelle and Tibetan antelope in the study area is 44240, 13162, and 2390, respectively. To evaluate the potential bias of the estimation, we took into account of survey uncertainties, model uncertainties, and adjustment uncertainties using the detaction function based on distance sampling, R 2 of species distribution models, and spatial heterogeneity of model-observation matchness. Our new method for estimating species abundance is suitable for species whose distribution is well correlated with environmental varibles, and the results of distance sampling are available.

Spatial dimensions play a significant role in niche differentiation, facilitating species coexistence. Understanding how sympatric ungulates optimize habitat utilization and how they co-exist in resource-limited environments is essential for effective wildlife conservation and reserve management. Tibetan antelope (chiru, Pantholops hodgsonii), Tibetan wild ass (kiang, Equus kiang), and wild yak (Bos grunniens) are sympatric ungulates co-evolving over generations across the Tibetan Plateau, but limited information is available on their spatial partitioning and the key variables affecting both single-species and multi-species distributions. In this study, using a combination of maximum entropy model, joint species distribution models, and random forest analysis, we examined the spatial partitioning of the three ungulates and identified the critical factors influencing their distributions with their spatial distribution data collected from the Arjin Shan National Nature Reserve in the Tibetan Plateau. Our key findings: (i) Notable differences were observed in the spatial distributions of the three ungulates, with only 16% overlap in their suitable habitats. Temperature had a stronger influence on the habitat selection by chiru and kiang, whereas precipitation played a more significant role in determining the distributions of kiang and wild yak. (ii) During summer, the interspecific relationships between chiru and wild yak, and between chiru and kiang exhibited positive correlations, while the relationship between wild yak and kiang was negatively correlated. In winter, all interspecific relationships were negatively correlated. (iii) Temperature seasonality and mean temperature of the driest quarter emerged as the most critical variables influencing multi-species habitat selection. Human interference had a significantly negative impact on all three ungulate species. Our findings underscore the importance of spatial heterogeneity in facilitating species coexistence under both climatic and anthropogenic pressures, offering valuable insights for multi-species conservation planning in resource-limited ecosystems.

Understanding the change in the habitat distributions and abundance of wildlife in space and time is critical for the conservation of biodiversity and mitigate human–wildlife conflicts (HWCs). Tibetan antelope or chiru (Pantholops hodgsonii), Tibetan gazelle or goa (Procapra picticaudata), Tibetan wild ass or kiang (Equus kiang), and Wild yak (Bos mutus) have been sympatric on the Qinghai–Tibetan plateau (QTP) for numerous generations. However, reviews on the habitat distributions and abundance of these four wild herbivores (WHs), as well as the methods examining the changes in these aspects, are still lacking. Here, we firstly review the distributions and abundance of four major WHs on the QTP across different periods, examining the underlying causes of changes and HWCs. Furthermore, we critically compare three aspects of methods: transect surveys, machine learning (ML), and deep learning (DL) methods of studying WHs. The results show that since the 1990s, the distributions and abundance of WHs have exhibited a trend of initial decline followed by recovery, largely attributed to global climate warming and a decrease in illegal hunting. However, in recent years, the primary challenge has shifted from wildlife protection to balancing the human and wildlife interests within the constraints of limited resources. In the future, we should focus on enhancing the ecological functions of habitats to achieve harmonious coexistence between humans and nature, as well as establishing a scientific compensation mechanism to mitigate human–wildlife conflicts. In order to accurately calculate the changes, we should select appropriate models to analyze the habitats of wildlife based on their specific characteristics and the environmental conditions. Additionally, with the advancement of large models, AI (artificial intelligence) should be utilized for precise and rapid wildlife conservation. The findings of this study also provide guidance and reference for addressing the issues related to wildlife habitats and abundance in other regions globally.

Why do Tibetan pastoralists hunt?

Understanding the use of small bridges and culverts by wildlife to cross the Qinghai–Tibet railway will aid in the design of wildlife crossing structures for similar transportation infrastructure. From 2014 to 2016, 36 infrared cameras were placed inside 14 small bridges and 11 culverts along the Qinghai–Tibet railway to determine the structures’ effectiveness as wildlife passages. Thirteen species of mammals were found to use the small bridges and culverts to cross the railway. The crossing rates for all mammals were significantly higher for small bridges than for culverts. Tibetan antelope (Pantholops hodgsonii), Tibetan gazelle (Procapra picticaudata), kiang (Equus kiang), and wild yak (Bos mutus) preferred small bridges over culverts to cross the railway. In contrast, mountain weasel (Mustela altaica) and Asian badger (Meles leucurus) preferred culverts to cross the railway. The crossing rates of all mammals, particularly Tibetan gazelle and woolly hare, were positively influenced by structure width. Structure height had a positive influence on wild yak, but structure length had a negative influence on kiang. The distance to the highway had a positive influence on the crossing rates of all mammals, particularly wild yak and woolly hare. Human use of the structures had no influence on the crossings of most mammals except for common wolf. We suggest that road design schemes include large and open crossing structures to benefit most species with limitations on human activities near wildlife passages.

Context Wild yak (Bos grunniens), Tibetan wild ass (Equus kiang, also known as kiang) and Tibetan antelope (Pantholops hodgsoni, also known as chiru) have been sympatric on the Tibetan Plateau for numerous generations. There is concern over potential dietary competition among them, particularly in winter when their forage resources are scarcer, but little is known about their dietary interactions. Aim We aimed to determine diet composition and dietary overlap of the three ungulate species, and to assess the extent of potential dietary competition among them in order to enhance our understanding of mechanisms underlying their co-existence. We predicted that the three species would widen their choice of forages in winter (December) compared with summer (June–July), and that there would be diet segregation among them, particularly in winter when food resources were scarcer. Methods We collected fresh faecal samples of the three species and reference forage samples from the field during our transect line surveys in the summers of 2012 and 2013, and winter of 2012 in Arjin Shan National Nature Reserve (ANNR) of Xinjiang Province, China. Slides of faecal samples were prepared for microhistological analysis, and plant fragments in faecal samples were identified under microscope. Relative percentage frequency of diet plant species, diet breadth and dietary overlap were calculated. Key results The three species consumed similar forage plants, but varied greatly in their percentage use of the available forages. Wild yak mainly fed on sedges in summer and graminoids in winter, supplemented with forbs. Kiang consumed mainly forbs in summer and browse in winter, and chiru mainly fed on graminoids and forbs in summer. Wild yak had the widest choice of forages, and kiang had the narrowest one in summer, but both wild yak and kiang became less selective in their food choice in winter, resulting in higher diet breadth. The dietary overlaps among them, as represented by Pianka’s index, were generally low, ranging from 0.26 between chiru and kiang to 0.51 between wild yak and kiang. The dietary overlap between wild yak and kiang decreased from summer (0.51) to winter (0.35), suggesting an increased dietary divergence. Key conclusion Our study reveals that the three species are ‘opportunistic feeders’, able to cope with coarse forage resources. There is dietary segregation among them as indicated by low dietary overlap, suggesting risk of potential competition for diets. We suggest that competition may have shaped their dietary divergence, contributing to their co-existence in ANNR. Implication Although there is dietary segregation among the three species in ANNR, it is not possible to make definitive conclusions about interspecific competition from these results. Further studies are needed to investigate if there is spatial and habitat segregation among them, which may facilitate their dietary divergence and thus contribute further to their co-existence in ANNR. Continued efforts are also needed to monitor their population dynamics and status of forage resources in order to prevent overgrazing.

Arjinshan National Nature Reserve (ANNR) is one of 3 refuges of the endemic ungulatesTibetan wild ass (Equus kiang), Chiru (Pantholops hodgsonii) and wild yak (Bos mutus) that are endangered by natural and anthropogenic factors in the Qinghai-Tibetan Plateau (QTP). Identifying habitat suitability is critical for species protection management. We used a GIS-based niche model to delimit and classify habitat suitability using an integrated assessment system, which included 9 biotic and abiotic factors. We divided the research area into 4 habitat types for these ungulates: (1) high suitability habitat; (2) moderate suitability habitat; (3) low suitability habitat; and (4) unsuitable area. Results suggested that chiru have the most areas of high and moderate suitability habitats while Tibetan wild ass had the largest areas of low suitability habitat and unsuitable area. Wild yak had the largest area of moderate and low suitability habitat, but high suitability habitats for wild yak were smaller than those of other 2 ungulates. There was overlap of high-quality habitat for the three kinds of ungulates in the vicinity of Kardun inspection station, which could be regarded as the core area for the coexistence and conservation of these endangered ungulate populations.

The Ladakh region of the Indian Trans-Himalaya supports twelve large herbivores, including eight mountain ungulates. Many of the species like the Tibetan antelope are highly endangered with rapidly declining populations. Yet there is little information on their status and distributions, especially in remote, inaccessible areas. We report on the status and distribution of five large herbivores in the Chang Chenmo and the Daulat Beg Oldi (DBO) areas of Ladakh, which remain the least known areas in Ladakh in terms of wildlife populations because they are very remote and politically highly sensitive. During the surveys, we observed 246 Tibetan antelopes and 40 blue sheep in DBO. In Chang Chenmo we observed 40 Tibetan antelopes, 2 wild yaks, 42 Tibetan argalis, 67 Tibetan wild asses and 30 blue sheep. In DBO, the encounter rate was higher for the Tibetan antelope (mean = 2.54, SE = 0.63) than the blue sheep (mean = 0.29, SE = 0.19). In Chang Chenmo the highest encounter rate was for the Tibetan wild ass (mean = 0.48, SE = 0.26), whereas the wild yak had the lowest (mean = 0.02, SE = 0.01). Since Chang Cehnmo and DBO are important areas for rare species in India, and are located right at the border with China, there is an urgent need for international collaboration to protect these threatened animals.DOI: http://dx.doi.org/10.3126/on.v9i1.5734

Variation in group sizes of sympatric Wild yak, Tibetan wild ass and Tibetan antelope in Arjin Shan National Nature Reserve of Xinjiang Province, China

Tibetan brown bear (Ursus arctos pruinosus) is an endemic subspecies of brown bear on the Qinghai-Tibetan plateau. We once reported a preliminary study on the summer food habit of Tibetan brown bear from July to August, 2005 in the Kekexili (Hoh Xil).. However, the hunting modes of the Tibetan brawn bear have not been reported. From July to August, 2009, we collected additional data on food habits and hunting patterns of Tibetan brown bear in the Kekexili region. We found Tibetan brown bears are more raptatorial than vegetarian, and their basal food was plateau pika (Ochotona curzoniae), relative frequency occurrence of pika in the fecal residual of brawn bear was 37.3%, dry weight of pika residuals was 44.7%, respectively, followed by wild yak (Bos grunniens) , 18.7% and 30.2%, and Tibetan antelope (Pantholops hodgsoni) 15.0% and 16.2%. Both prey actively mode and scavenge mode were used by Tibetan brown bears in Kekexili. Tibetan brawn bears actively dug and hunted for pika and scavenged bodies of wild yak, Tibetan antelope and Tibetan gazelle. We observed that Tibetan brawn bears spent about 10% of their time to dig and to hunt for pika but we had never seen Tibetan brawn bears actively hunted large mammals such as wild yak, Tibetan antelope and Tibetan gazelle. The total amount of Tibetan antelope, Tibetan gazelle and wild yak ingested by Tibetan brown bear through scavenge was about the same amount of Plateau pika and Himalayan marmot (Marmota himalayana) eaten by the bear.

The targets of China’s national park construction are to protect the authenticity and integrity of the ecosystems, and to achieve the harmonious development between humans and nature. Because of the high intensity of human activities, the authenticity of ecosystems has deviated over the past few decades. It is time to rewild the wildlife and restore the authenticity of these ecosystems. The status of rewilding wildlife in Sanjiangyuan National Park, indicating that the wildlife population, diversity and wildness have increased within the National Park. The wildlife population in the national park has been restored, with about 60,000 Tibetan antelope, 60,000 Tibetan gazelle, 36,000 Tibetan wild ass, 10,000 wild yak, and 10,000 white-lipped deer up to 2017. However, overgrazing existed on the alpine grassland with population increasing both of ungulates and livestock.

Modelling species distributions with remote sensing data: bridging disciplinary perspectives