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Vegetation patch patterns, which are used as indicators of state, functionality, and catastrophic changes in the arid ecosystem, have received much attention. However, little is known about the controlling factors and indicators that underlie vegetation patch patterns in the alpine grassland ecosystem. Here, we firstly studied characteristics of vegetation patch patterns with aerial photography by using an unmanned aerial vehicle and evaluated the vegetation patch-size distribution with power law (PL) and truncated power law (TPL) models on the central part of the Qinghai-Tibetan Plateau (QTP). We then investigated the effects of environmental factors and biotic disturbances on vegetation patch patterns. The results showed that (1) there were four typical vegetation patch patterns, i.e. spot, stripe, sheet, and uniform patterns; (2) soil water content and air temperature were major environmental factors affecting vegetation patch patterns; (3) biotic disturbance of plateau pika (Ochotona curzoniae) affected vegetation patch patterns by changing the number, area, and connectivity of vegetation patches; and (4) vegetation patch-size distribution parameters were significantly related to soil hydrothermal variables (P

Detailed characterization of alpine meadow ecosystems using spatial metrics is important to understand the underlying processes of meadow degradation and to inform its proper management. The change in the fragmentation of the alpine meadow on the Qinghai-Tibet Plateau during 2018–2019 was studied in relation to plateau pika (Ochotona curzoniae) population and simulated grazing both independently and interactively. For the first time this study has quantified their effect on the changes in the spatial metrics of ​​bare and healthy meadow patches with the assistance of multi-temporal UAV images in ArcGIS. The spatial index reflecting the fragmentation degree of landscape caused by external disturbances was obtained via spatial analysis in the Fragstats 4.2 software. The results showed that the impact of pika on landscape fragmentation was higher than that of simulated grazing, so pikas populaton should be controlled within the manageable level. The influence of each disturbance on the degree of fragmentation was the highest in high density pika and severe mowing plot, followed by the plots of medium density pika, the control treatments, high density pika, other three interactive effect groups, moderate mowing and severe mowing. In the interactive effect, at the same mowing intensity, landscape fragmentation increased with pika population. At the same pika population, landscape fragmentation increased with mowing intensity. The correlation coefficient between the change in pika burrows and area of bare patches is 0.538, and the proportion of bare patches to the landscape is 0.541. This study provides a reference for studying the feasibility of grassland fragmentation monitoring in the future and the landscape stability of the alpine meadow.

The plateau pika (Ochotona curzoniae) is a species of sprint-running alpine animals in the Qinghai-Tibet Plateau, which is a harsh highland hypoxic environment. Ldh-c is expressed in the testis, sperm and somatic tissues of plateau pika. To reveal the role and physiological mechanisms of sperm-specific lactate dehydrogenase (LDH-C4), in plateau pika to adapt to hypoxic environment, an adenoviral line of pMultiRNAi-Ldhc was constructed and injected into the bilateral biceps femoris of the hind legs. The swimming times of the pikas, and the Ldh-c expression levels, total LDH activities and ATP levels in skeletal muscle, were measured after the pikas were raised in the trapped site for 5 days. Our results showed that after Ldh-c was silenced, the sprint-running ability (swimming time) of the plateau pikas was significant decreased, and the total LDH activities and ATP levels were reduced by 28.21% and 27.88%, respectively. Our results indicated that expression of Ldh-c in the skeletal muscle of plateau pika increased anaerobic glycolysis and enhanced adaptation to highland hypoxic environments., Summary: The expression of Ldh-c in the skeletal muscle of plateau pika (Ochotona curzoniae) increases anaerobic glycolysis, resulting in enhanced sprint-running capacity and adaptation to a hypoxic environment.

The plateau pika ( Ochotona curzoniae ), one of the main bioturbators, creates extensive disturbances in the soil of the alpine meadow of the Qinghai-Tibet Plateau (QTP). This study investigated the effects of the presence and intensity of plateau pika disturbances on the main soil nutrients of the Kobresia pygmaea meadow across three study sites in the QTP by using the method of counting the active burrow entrance densities of plateau pika in the field as a representation of the disturbance intensity. Our results showed that the presence of plateau pika significantly increased the soil total nitrogen (TN), soil organic carbon (SOC) and total phosphorus (TP) concentrations and decreased the available phosphorus (AP) concentrations across the three study sites. The presence of plateau pika increased the NO 3 − -N and NH 4 + -N concentrations in Luqu County and Maqu County, but had no significant effect on these concentrations in Gonghe County. The soil TN, SOC and TP concentrations showed a downward parabola and the NO 3 − -N, NH 4 + -N and AP concentrations showed an upward parabola as the intensity of the disturbances increased in Luqu County and Maqu County. These soil nutrients had a threshold (inflection point) of 475 (475 ± 90) burrow entrances per ha. However, the soil TN, SOC and TP concentrations increased linearly while the NO 3 − -N, NH 4 + -N and AP concentrations decreased linearly with the increasing intensity of disturbances in Gonghe County (≤512 burrow entrances per ha). These results implied that the soil nutrient changes induced by plateau pika disturbances are not only related to their presence but are also related to the intensity of the disturbances, and that the most appropriate disturbance intensity (475 (475 ± 90) burrow entrances per ha) of plateau pika was beneficial to the storage of soil carbon and nitrogen in the alpine meadow in the QTP.

Two strains (pika_113T and pika_114) of a previously undescribed Actinomyces -like bacterium were recovered from the intestinal contents of plateau pika (Ochotona curzoniae) on the Tibet-Qinghai Plateau, China. Results from biochemical characterization indicated that the two strains were phenotypically homogeneous and distinct from other previously described species of the genus Actinomyces . Based on the comparison of 16S rRNA gene sequences and genome analysis, the bacteria were determined to be a hitherto unknown subline within the genus Actinomyces , being most closely related to type strains of Actinomyces denticolens and Actinomyces timonensis with a respective 97.2 and 97.1 % similarity in their 16S rRNA gene sequences. Phylogenetic analyses confirmed that pika_113T was well separated from any other recognized species of the genus Actinomyces and within the cluster with A. denticolens and A. timonensis. The genome of strain pika_113T displayed less than 42 % relatedness in DNA–DNA hybridization with all the available genomes of existing species of the genus Actinomyces in the NCBI database. Collectively, based on the phenotypic characteristics and phylogenetic analyses results, we propose the novel isolates as representatives of Actinomyces gaoshouyii sp. nov. The type strain of Actinomyces gaoshouyii is pika_113T (=CGMCC 4.7372T=DSM 104049T), with a genomic DNA G+C content of 71 mol%.

Patchy alpine grassland with soil excavated by plateau pika (Ochotona curzoniae) and with bald patches is common on the Qinghai-Tibetan Plateau (QTP) where desertification has developed rapidly over the last few decades. This may have significant effects on alpine grassland restoration, by changing soil properties. In this study, the contribution of plateau pika disturbance and erosion on patchy alpine grassland soil were examined by classifying the surface of the patchy grassland into 4 types—vegetation patch, new pika pile, old pika pile and bald patch—and comparing the gravel content of the top layer of soil, soil moisture, soil hardness, soil organic carbon (SOC), and soil total nitrogen (TN) among them in the four study areas with different climatic conditions, altitudes, and grassland types on the QTP. We also analyzed the relationship between the amount of soil surface gravel and the Green Fractional Vegetation Cover (GFVC) using aerial photos. The results showed that (1) gravel content was significantly greater in bald patches and pika piles than in vegetation patches (p

Variations of plant biomass and plant species diversity in relation to plateau pika densities in alpine meadow steppe of the Qinghai-Tibet Plateau China were investigated. Peak above- and below-ground biomass, botanical composition, and soil moisture were measured and from these species and functional diversity indices were calculated with reference to pika burrow densities, biomass and soil moisture. Biomass components generally decreased with increased pika burrow density. Biomass of sedges and forbs increased whereas aboveground biomass of grasses first increased and then decreased as burrow density increased. There were positive linear relationships between aboveground biomass and both species and functional group richness and diversity, and also between soil moisture and these indices. These results are relevant to considerations of whether plateau pika is a pest or is a key species in maintaining the ecological stability and biodiversity of its indigenous habitat.

With hypoxic stress, hypoxia-inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) are elevated and their responses are altered in skeletal muscles of plateau animals [China Qinghai-Tibetan plateau pikas (Ochotona curzoniae)] as compared with control animals [normal lowland Sprague-Dawley (SD) rats]. The results indicate that HIF-1alpha and VEGF are engaged in physiological functions under hypoxic environment. The purpose of the current study was to examine the protein levels of VEGF receptor subtypes (VEGFRs: VEGFR-1, VEGFR-2 and VEGFR-3) in the end organs, namely skeletal muscle, heart and lung in response to hypoxic stress. ELISA and Western blot analysis were employed to determine HIF-1alpha and the protein expression of VEGFRs in control animals and plateau pikas. We further blocked HIF-1alpha signal to determine if HIF-1alpha regulates alternations in VEGFRs in those tissues. We hypothesized that responsiveness of VEGFRs in the major end organs of plateau animals is differential with insult of hypoxic stress and is modulated by low oxygen sensitive HIF-1alpha. Our results show that hypoxic stress induced by exposure of lower O(2) for 6 h significantly increased the levels of VEGFR-2 in skeletal muscle, heart and lung and the increases were amplified in plateau pikas. Our results also demonstrate that hypoxic stress enhanced VEGFR-3 in lungs of plateau animals. Nonetheless, no significant alternations in VEGFR-1 were observed in those tissues with hypoxic stress. Moreover, we observed decreases of VEGFR-2 in skeletal muscle, heart and lung; and decreases of VEGFR-3 in lung following HIF-1alpha inhibition. Overall, our findings suggest that in plateau animals 1) responsiveness of VEGFRs is different under hypoxic environment; 2) amplified VEGFR-2 response appears in skeletal muscle, heart and lung, and enhanced VEGFR-3 response is mainly observed in lung; 3) HIF-1alpha plays a regulatory role in the levels of VEGFRs. Our results provide the underlying cellular and molecular mechanisms responsible for hypoxic environment in plateau animals, having an impact on research of physiological and ecological adaptive responses to acute or chronic hypoxic stress in humans who living at high attitude and who live at a normal sea level but suffer from hypoxic disorders.

The mammalian stomach acts as an important barrier against ingested pathogens into the entire gastrointestinal tract, thereby playing a key role in host health. However, little is known regarding to the stomach microbial compositions in wild mammals and the factors that may influence the community compositions. Using high-throughput sequencing of the 16S rRNA gene, we characterized the stomach bacterial community compositions, diversity, and interactions in two common pika (Ochotona sp.) species in China, including Plateau pikas (Ochotona curzoniae) and Daurian pikas (Ochotona daurica) living in the Qinghai-Tibet Plateau and the Inner Mongolia Grassland, respectively. The bacterial communities can be divided into two distinct phylogenetic clusters. The most dominant bacteria in cluster I were unclassified bacteria. Cluster II was more diverse, predominantly consisting of Bacteroidetes, followed by unclassified bacteria, Firmicutes and Proteobacteria. Three dominant genera (Prevotella, Oscillospira, and Ruminococcus) in pika stomachs were significantly enriched in cluster II. In addition, seasons, host species, and sampling sites as well as body weight and sex had no significant impacts on the composition and diversity of pika stomach communities. Interestingly, Plateau pikas harbored a more complex bacterial network than Daurian pikas, and these two pika species showed different co-occurrence patterns. These results suggested that the pika stomach harbors a diverse but relatively stable and unique bacterial community, which is independent on host (host species, body weight, and sex) and measured environmental factors (sampling sites and seasons). Interestingly, host species shapes the microbial interactions rather than diversity of stomach bacterial communities in pikas, reflecting specific niche adaptation of stomach bacterial communities through species interactions.

Background Bartonella bacteria have been associated with an increasingly wide range of human and animal diseases and were also recognized to be globally dispersed as emergent pathogens. Ticks and small rodents are known vectors of human and animal bartonellosis and play important roles in maintenance and circulation of bartonellae in nature. In China, Shiqu county is located on the eastern Qinghai-Tibetan plateau and about 26 thousands square kilometers with an average altitude of above 4,200 meters and vast area of pastureland. In present study, the occurrence of Bartonella spp. in ticks and plateau pika was firstly investigated in Shiqu county.Results A total of 818 ticks ( Dermacentor everestianus , 79.0%, 646/818; Haemphysalis qinghaiensis , 21.0%, 172/818), were collected in 4 villages in Shiqu county. Only Bartonella melophagi was detected in tick samples with a total prevalence of 30.1% (246/818). Significant difference was observed (P0.05) between theses study sites. Conclusion At present, only D.everestianus and H.qinghaiensis were found in Shiqu county with high infection of Bartonella spp. in theses ticks and plateau pika. The threats to public health by these Bartonella species should be monitored.

The plateau pika (Ochotona curzoniae) is a keystone species in the alpine rangeland ecosystem of the Qinghai&ndash, Tibetan Plateau. Most previous studies of habitat selection by plateau pika have been conducted at a local microhabitat scale, however, little is known about the relationship between the distribution of plateau pika and macrohabitat factors at broad spatial scales. Using a presence-only ecological niche model (maximum entropy, Maxent), we predicted the distribution of plateau pika in the Qinghai Lake basin based on a set of environmental and anthropogenic variables at 1-km spatial resolution, and identified key macrohabitat factors that contribute to the predictive performance. Our results showed suitable area for plateau pika in the Qinghai Lake basin being approximately 3982 km2, which is 15.8% of the land area in the whole watershed. The distance to road emerged as the most important predictor of the distribution patterns of plateau pika, while the soil type was of ancillary importance. Mean air temperature of wettest quarter, distance to resident site and altitude also produced high gains in defining plateau pika&rsquo, s distribution. A higher predictive accuracy was achieved by the model that combined environmental and anthropogenic variables. With the constraint of human factors, the presence probability of plateau pika in about 1661 km2 will increase. These findings demonstrate the impact of human activities on the distribution of plateau pika, and the importance of vegetation reservation for plateau pika control.

Background Animals inhabiting high altitudes consistently show slow life-histories. The pace-of-life syndrome (POLS) hypothesis posits behavioural, physiological and/or morphological traits that mediate the trade-off between current and future reproduction or survival, which have coevolved along a slow-fast life history continuum. Previous studies have shown that the life histories of plateau pikas varied across altitude, high-altitude individuals showed slow pace of life which were characterized by few litters per year with small litter sizes. Thus, we hypothesized that pikas populations at higher altitudes would also express personalities characteristic associated with slow life history, such as high sociability, low activity or aggressiveness. We tested this hypothesis by comparing the activity and docility of three plateau pika (Ochotona curzoniae) populations distributed along an altitudinal gradient of the Tibetan Plateau. We predicted that high-altitude pika would be more docile and less active. Results The behaviour of 556 pikas, from which 120 individuals were measured at least twice, was quantified. We observed that plateau pikas at high altitudes were less active and more docile than pika at lower altitudes. Activity and docility were significantly and negatively correlated in populations from high altitudes but not in populations from low altitudes. Conclusions Our results support the POLS hypothesis, highlight the existence of personality variation among populations distributed along an altitudinal gradient and emphasise the importance of environmental selection on personality divergence.

Three independent isolates (10022T, 10 009 and 10011) of a novel catalase-positive, Gram-stain-negative coccus in the genus Neisseria were obtained from the rectal contents of plateau pika on the Qinghai–Tibet Plateau, PR China. Based on 16S rRNA gene sequence analysis, our newly identified organisms were most closely related to Neisseria iguanae , Neisseria flavescens and Neisseria perflava with similarities ranging from 98.02 to 98.45 %, followed by seven other species in the genus Neisseria . Phylogenetic analysis based on 16S rRNA and rplF genes showed that our three novel isolates group with members of the genus Neisseria . Results of the average nucleotide identity (ANI) analysis confirmed that our isolates are of the same species, and the ANI values between type strain 10022T and other Neisseria species are 74.12–85.06 %, lower than the threshold range of 95–96 %. The major cellular fatty acids for our novel species are C16 : 0 and C16:1ω7c/C16:1ω6c, which along with their phenotypic characteristics can distinguish our isolates from other Neisseria species. On the basis of polyphasic analyses, our isolates are proposed to represent a novel species in genus Neisseria , with the name Neisseria weixii sp. nov. The type strain is 10022T (=DSM 103441T=CGMCC 1.15732T).

Plateau zokor (Myospalax baileyi) and plateau pika (Ochotona curzoniae) are endemic fossorial vertebrates in the Qinghai–Tibetan Plateau alpine meadow ecosystem. Their different burrowing activities together transform soil structure and then significantly change the landscape of meadow ecosystem. However, how their burrowing activities impact greenhouse gas (GHG) emissions and the pattern of GHG emissions between different types of tunnel burrowing still remain obscure. In this study, we conducted in situ measurements quantitatively investigating the impacts of the different burrowing activities of zokors and pikas on three main GHG CO2, CH4, and N2O from an alpine meadow ecosystem in southeastern Qinghai–Tibetan Plateau. Our results showed that zokor hummocks and pika burrows were sources of CO2 and N2O and sinks of CH4. Zokors burrowing increased N2O in the atmosphere, decreased CO2, and enhanced CH4 absorbing, while pikas burrowing increased N2O in the atmosphere and enhanced CH4 absorbing. Considering the controversial role of fossorial vertebrates in Qinghai–Tibetan Plateau, this study also shed lights on effective management of animal activities with the aim of stabilizing or increasing ecosystem carbon sequestration.

In order to effectively solve this problem that that the traditional level set method needs to mark the initial contour manually, a novel method that automatic initialization by utilizing deep learning is proposed in this paper. Firstly, a target detection network based on Faster-RCNN is used for target detection of ochotona curzoniae. Secondly, the detected target boxes are regarded as the initial contour of level set models, and ochotona curzoniae images are segmented by level set models, by which the problem of manually plotting the initial contour required by traditional level set models is solved. The experimental results of ochotona curzoniae image segmentation show that there is little difference between the level set segmentation method in which the initial contour of the target is automatically generated by deep learning(LSECA) is used to automatically target initial contour and the level set segmentation method where initial contour needs to be manually plotted. Therefore, the experimental results prove that it is feasible to automatically obtain the target initial contour through deep learning.

When population abundances exceed the economical or ecological threshold, animals are always regarded as pests, so effective and sustainable management strategies are required. As a native species widely distributed on Tibetan Plateau, plateau pika is regarded as a pest when its abundance is too high. For decades, plateau pika were controlled using toxic baits by both the local government and shepherds. However, how pika population fluctuates after lethal control is far from certain. Based on our previous studies, demographic parameters of plateau pika were acquired. A system dynamics model is developed to parameterize a population model for this species. The model incorporates two age categories (juvenile and adult) of both sexes, and uses density-dependent factors, including reproduction, mortality, and migration. The model is used originally to analyze the effect of pika management on the population dynamics and resulting abundance, in order to plan optimal pest controlling strategies. The results show that lethal control is efficient when continuously conducted once each year, or twice with 2-year intervals. For sustainable controlling pest abundance, comprehensive strategies should be considered. An appropriate population model could be used to explore the optimal strategies and provide important reference into decision making about pest management.

The burrows of the plateau pika (Ochotona curzoniae) increase microhabitat heterogeneity and provide breeding sites and refuge for several vertebrate species on China's Qinghai-Tibetan Plateau. Despite their important role in the ecosystem, pikas are poisoned in China and have been extirpated in some areas. The Qinghai toad-headed agama (Phrynocephalus vlangalii) has been referred to as strongly dependent on pika burrows, although their relationship has never been studied in any detail. We used single-season occupancy models to investigate the influence of pika colonies on probability of site occupancy by P. vlangalii in China's Yanchiwan National Nature Reserve. Models containing pika burrow density as a predictor performed no better than the null model. Absolute values of estimated β-coefficients associated with burrow density were also very small (

Exploring animals’ responses to climate change will improve our understanding of the ecological consequences of such a phenomenon. As the “third pole” of the earth, the Tibetan Plateau is sensitive to climate change. To explore the effects of climate change on the reproduction of small mammals in an arid environment, we tested the reproduction of a native species, plateau pika (Ochotona curzoniae), from 2005 to 2009 in Dawu, which is located east of the Tibetan Plateau. The breeding season of this population maintained a stable onset date, but the length of breeding season varied from 53 to 84 days. The April temperature and spring precipitation positively affected the length of the breeding season. The offspring sex ratio was female biased except in 2009, whereas the ratio of recruits per reproductive female (RRF) ranged from 2.7 to 4.4. The April temperature and the normalized difference vegetation index (NDVI) in June positively affected the offspring sex ratio, whereas the precipitation in cold seasons and May NDVI positively affected the RRF. Therefore, increased temperature, precipitation, and NDVI may extend the length of the breeding season, increase the sex ratio, and produce more offspring recruits.

The plateau pika ( Ochotona curzoniae ) is considered a keystone species on the Qinghai–Tibetan Plateau (QTP). Under a moderate burrow density condition, we investigated plant community and soil properties surrounding pika's burrows in comparison to the control sites (without pika's burrows) in an alpine meadow ecosystem. The results demonstrated that plant biomass, especially aboveground biomass around pika's burrow, was improved. The contents of available soil nutrients around the pika's burrow were improved as well. The highest aboveground biomass and highest contents of NH 4 -N, available phosphorus and available potassium was detected at the back of the burrow. The compositions of plant community were not changed significantly around the pika burrow, excluding at the front of the burrow. Our findings revealed that the activities of plateau pika can improve the production of alpine meadow and increase the soil fertility at individual burrow level when the burrow density was not out of control.

The plateau pika (Ochotona curzoniae), a small burrowing lagomorph that occupies the high alpine grasslands of the Qinghai-Tibetan Plateau (QTP), has been subject to a massive eradication campaign in China since the late 1950′s under the assumption that it promotes grassland degradation. However, mounting evidence suggests that pikas are a keystone species that provide critical ecological services in the alpine meadow ecosystem. Since the implementation of pika control programs, few studies have investigated the potential impacts of pika poisoning on native carnivore species. In 2007 we investigated the impact of pika poisoning on carnivores in southern Qinghai Province, China. Our results show a decrease in the abundance of carnivores from areas where pikas had been poisoned compared with non-poisoned sites, suggesting that the eradication of pikas at regional scales may alter or disrupt ecological communities on the QTP.

There are many factors influencing prey’s risk perception and escape decision during predator–prey encounters. The distance at which animals move away from perceived danger (often quantified as flight initiation distance or FID) has been used by behavioral ecologists to understand the economics of antipredator behavior. Using general linear models, we investigated escape decision-making processes in plateau pika (Ochotona curzoniae (Hodgson, 1858)) and White-rumped Snowfinch (Onychostruthus taczanowskii (Prjevalsky, 1876), formerly known as Montifringilla taczanowskii Przewalski, 1876) together and we found that (i) there are significant positive correlations between starting distance and FID in both species; (ii) pika escapes at a longer distance from an approaching intruder when it is far from its burrow; (iii) foraging animals tolerate closer distances than watching ones, both in pikas and in Snowfinches; (iv) conspecifics seem to have no effect on pikas’ escaping behavior, while the appearance of Snowfinches dramatically decreases the FID of pikas. On the contrary, conspecifics significantly decrease the FID of Snowfinches, while the presence of pikas has no effects. These findings provide new evidence, which are consistent with optimal escape theory. These novel results in multispecies interactions prompt us to pay attention to the potential relationship between pikas and Snowfinches, as well as the “bird–pika in one hole” phenomenon.

The presence of small burrowing herbivores often cause extensive disturbance to the grassland soil nutrient stocks. This study investigated the effect of small burrowing herbivore presence, the plateau pika (Ochotona curzoniae), and variation in disturbance intensity on soil nitrogen stocks at five alpine meadow sites. Disturbed plots occupied by plateau pikas consist of burrows and their associated bare soil patches in a matrix of continuous alpine meadow. The percentage of the bare soil area in a disturbed plot was used as a proxy for disturbance intensity of plateau pikas. This study showed that the soil total nitrogen stock was lower of bare soil than vegetated soil within disturbed plots, while ammonium nitrogen (NH4+-N), nitrate nitrogen (NO3−-N), inorganic nitrogen and ammonium nitrogen/nitrate nitrogen ratio (ANR) were higher in bare soil than vegetated soil within the disturbed plots. This study further showed that the NH4+-N, inorganic nitrogen and ANR of disturbed plots were higher than those of undisturbed plots, whereas soil total nitrogen and the NO3−-N stock was not different between disturbed plots and undisturbed plots. This study also showed that the soil total nitrogen, NH4+-N and inorganic nitrogen stocks of disturbed plots were higher at intermediate disturbance intensities of plateau pikas, whereas the NO3−-N stock and ANR were not related to disturbance intensities. These results suggest that the NH4+-N and inorganic nitrogen stocks were higher in the presence of plateau pikas, and intermediate disturbance intensity of plateau pikas was beneficial for soil quality due to higher soil total nitrogen, NH4+-N and inorganic nitrogen stocks. The findings of this study present a possible approach for estimating how the presence of a small burrowing herbivore influences grassland soil nitrogen stock.

The plateau pika (Ochotona curzoniae) is a common small mammal species present in the alpine meadow ecosystem on the Qinghai-Tibetan Plateau (QTP), and is regarded as a pest in alpine meadows when population density exceeds a certain threshold. However, whether pikas with a low population density have a detrimental effect on alpine meadows in winter pasture is unknown. Vegetation and soil were sampled in eight individual pika patchy home ranges and eight control areas, and we found vegetation and soil properties showed different trends in the pika home ranges. Plateau pika activity significantly increased the below-ground biomass, soil pH and total potassium, but had no significant effect on the plant species richness or diversity, soil moisture, NH4-N, NO3-N, total phosphorus, available phosphorus and soil organic content. However, plateau pika activity reduced some vegetation and soil properties (e.g. vegetation cover, vegetation height, aboveground biomass, graminoids, soil bulk density and available potassium). These results imply that pika activity may improve some soil nutrients but have no destructive effect on winter pasture at a low population density.

There is considerable controversy about the effects of plateau pika (Ochotona curzoniae, hereafter pika) on alpine grassland on the Qinghai-Tibet Plateau (QTP). On the one hand, pika is considered a keystone species. On the other hand, it is being poisoned. Although significant efforts have been made to study the effects of pika at a quadrat scale ( ∼ m2), our knowledge about its distribution and effects at a larger scale is very limited. In this study, we investigated the direct effects, i.e., burying and grazing, of pika by upscaling field sampling at a quadrat scale to a plot scale ( ∼ 1000 m2) by aerial photographing. Altogether 168 plots were set on four different types of alpine grassland in a semiarid basin on the QTP. Results showed that (1) the effects of pika pile burying on the reduction of vegetation cover, biomass, soil carbon, and nitrogen were less than 10 %, which was much smaller than the effects of bald patches; and (2) pika consumed 8–21 % of annual net primary production of grassland. We concluded that the direct burying and grazing effects of pika on alpine grassland were minor in this region. The quadcopter is an efficient and economic tool for long-term repeated monitoring over large regions for further understanding the role of pika.

Two Gram-stain negative, catalase positive, coccus shaped bacteria, designated 10023T and 10010, were isolated from the rectal contents of a plateau pika (Ochotona curzoniae) in Qinghai–Tibet Plateau, China. Based on 16S rRNA gene sequence analysis, phylogenetic trees showed that these two isolates (10023T, 10010) group with members of the genus Neisseria. Additionally, these two isolates exhibited high 16S rRNA gene sequence similarity with Neisseria zalophi CSL 7565T (96.98%), Neisseria wadsworthii WC 05-9715T (96.92%) and Neisseria canis ATCC 14687T (96.79%). Further phylogenetic analysis based on the rplF gene showed that these two novel strains can be easily discriminated from phylogenetically closely related species. Optimal growth was found to occur on BHI agar with 5% defibrinated sheep blood at 37 °C and growth was also observed on nutrient agar, Columbia blood agar and chocolate agar plates; however, growth was not observed on MacConkey agar after 7 days. The major cellular fatty acids of these strains were identified as C16:0 and C16:1ω7c/C16:1ω6c. The complete genome size of the type strain 10023T is 2,496,444 bp, with DNA G+C content of 54.0 mol %. The average nucleotide identity values were 73.5–79.3% between isolate 10023T and reference Neisseria spp. Based on polyphasic analysis, these isolates (10023T and 10010) are considered to represent a novel species in the genus Neisseria, for which the name Neisseria chenwenguii sp. nov. is proposed. The type strain is 10023T (= DSM 103440T = CGMCC 1.15736T). Electronic supplementary material The online version of this article (10.1007/s10482-019-01234-2) contains supplementary material, which is available to authorized users.

This paper demonstrates the impact of an endemic fossorial animal, plateau pika (Ochotona curzoniae), on soil properties and N2O flux at the Zoige Wetland. Pika burrow and control sites without disturbance by pika were selected to measure the soil water content, bulk density, soil organic matter (SOM), NH4-N content and NO3-N content in August 2012. N2O fluxes were measured with static opaque chambers at these sites in June and August 2012. Pika burrowing altered soil aeration by transferring deeper soil to the surface and by constructing underground burrows, which significantly increased bulk density, and reduced soil water content, SOM and NH4-N content at 0-10 cm and 10-20 cm soil depth. N2O flux had a significant correlation with bulk density, SOM and NH4-N content. Pika burrowing significantly influenced N2O flux by increasing N2O flux at the control site from near zero to 0.063±0.011 mg m-2 h-1. Our findings described how pika burrowing influences the soil traits and significantly increases the principal greenhouse gas N2O emission. As plateau pika was commonly considered as a pest, our findings give a novel clue to effectively manage populations of plateau pika on the Qinghai-Tibet Plateau from the perspective of greenhouse gas emission.

Frequent outbreaks of plateau pika (Ochotona curzoniae) have become a major challenge for the sustainability of Tibetan rangeland, although top-down control has been widely employed since the 1960s over the plateau. Based on studies on plant trait-mediated soil-plant-herbivore relations, we hypothesized that impoverished soil was a consequence of rangeland degradation as well as a cause of increasing pika numbers through lowered functional trait diversity (FD) of the plant community that provides advantages for pika fitness. At three sites of alpine meadows on the eastern Tibetan Plateau, we counted active burrows of pika in 27 plots (i.e., 9 plots per site) distributed along a gradient of soil fertility. For every plant species within each plot, we measured five functional traits (e.g., mature height, SLA: specific leaf area, LDMC: leaf dry matter content, and leaf N and P: leaf nitrogen and phosphorus concentrations), indicating plant performance in response to changing soil fertility and impacting the fitness of pika. We employed Bayesian regression, structural equation modeling and network analyses to assess causal relations from soil fertility to FD and burrow density. The results show i) there was no significant difference in burrow density between three sites; spatial variation among plots in terms of soil fertility, plant species diversity and FD accounted for 57%–72%, 26%–41% and 59%–73%, respectively, of the variation in burrow density; ii) the burrow density was associated positively with soil moisture and organic matter, plant coverage, forb abundance and FD of leaf P, but negatively with soil nutrients, plant species diversity and FD for SLA, height and leaf N; and iii) deficiency of soil P potentially resulted in an increase in pika density, likely through lowered FD of SLA and height, with other soil factors and FD of leaf nutrients indirectly associated with burrow density. Our study suggested that under the joint effect of intensive grazing by livestock and output of livestock products from region, deficiency of soil P potentially increased pika density, likely by supporting more and diverse food resources while decreasing the risk of being preyed upon. Control of pika outbreak should pay more attention to bottom-up restoration of degraded soil and vegetation via traditional rotational grazing and promotion of recycling and compensation of lost soil P and plant trait diversity.

The pika (Ochotona curzoniae) hole is an important landscape feature in the Tibetan Plateau (TP) grasslands, and it indicates grassland degradation levels due to the destruction caused by pika burrowing activities on grasslands. However, no studies have ever explored landscape patterns of pika holes and their effects on adjacent vegetation coverage. Taking meadow grasslands in Northern Tibet as an example, this study gathered unmanned aerial vehicle (UAV) images and explored landscape patterns of pika holes and their effects on grass coverage in the surroundings. The performances of two classification methods, including the decision tree classification based on Fully Constrained Least Squares (FDC) and the object-oriented classification (OBC) were compared in recognizing sizes and shapes of pika holes. The results showed that: (1) The object-oriented classification exhibits higher classification accuracy in identifying pika holes. (2) The average size of pika holes in the study area is 0.01 m2 and they exhibit clustered distribution patterns. The average distance between any two nearest pika hole patches is 0.79 m. (3) It presents a significant quadratic relationship between the number of pika holes and grass coverage. (4) The average effective distance of pika holes on the surrounding grass coverage is 20 cm. The findings of this study can provide guidelines for pika control and improve grassland management on the TP.

Background\ud The eastern part of the Tibetan Plateau is now recognized as an endemic region with the highest reported human infection rates in the world of human alveolar echinococcosis (AE) caused by Echinococcus multilocularis. Existing epidemiological studies on AE have mainly focused on the synanthropic environment, while basic parasitological and ecological aspects in wildlife host species remain largely unknown, especially for small mammal hosts. Therefore, we examined small mammal host species composition, occurrence, and the prevalence of both E. multilocularis and E. shiquicus in Shiqu County (Sichuan Province, China), eastern Tibetan Plateau.\ud \ud Results\ud In total, 346 small mammals from five rodent and one pika species were trapped from four randomly set 0.25 ha square plots. Two vole species, Lasiopodomys fuscus (n = 144) and Microtus limnophilus (n = 44), and the plateau pika (Ochotona curzoniae) (n = 135), were the three most-dominant species trapped. Although protoscoleces of E. multilocularis and E. shiquicus were only observed in L. fuscus and O. curzoniae, respectively, cox1 and nad1 gene DNA of E. shiquicus was detected in all the small mammal species except for Neodon irene, whereas E. multilocularis was detected in the three most-dominant species. The overall molecular prevalence of Echinococcus species was 5.8 (95% CI: 3.3–8.2%) ~ 10.7% (95% CI: 7.4–14.0%) (the conservative prevalence to the maximum prevalence with 95% CI in parentheses), whereas for E. multilocularis it was 4.3 (95% CI: 2.2–6.5%) ~ 6.7% (95% CI: 4.0–9.3%), and 1.5 (95% CI: 0.2–2.7%) ~ 4.1% (95% CI: 2.0–6.1%) for E. shiquicus. The prevalence of both E. multilocularis and E. shiquicus, was significantly higher in rodents (mainly voles) than in pikas. Phylogenetic analyses revealed that Echinococcus haplotypes of cox1 from small mammal hosts were actively involved in the sylvatic and anthropogenic transmission cycles of E. multilocularis in the eastern Tibetan Plateau.\ud \ud Conclusions\ud In contrast to previous studies, the current results indicated that rodent species, rather than pikas, are probably more important natural intermediate hosts of E. multilocularis and E. shiquicus in the eastern Tibetan Plateau. Thus, understanding interspecific dynamics between rodents and pikas is essential to studies of the echinococcosis transmission mechanism and human echinococcosis prevention in local communities.\ud \ud Keywords:\ud Echinococcus multilocularis, E. shiquicus, Small mammal Prevalence, Tibetan Plateau

During evolution, animals optimize their reproductive strategies to increase offspring survival. Seasonal breeders reproduce only during certain times of the year. In mammals, reproduction is tightly controlled by hypothalamus-pituitary-gonad axis. Although pathways regulating gametogenesis in non-seasonal model species have been well established, molecular insights into seasonal reproduction are severely limited. Using the Plateau pika (Ochotona curzoniae), a small rodent animal species native to the Qinghai-Tibetan plateau, as a model, here we report that seasonal spermatogenesis is governed at the level of spermatogonial differentiation. In testis of the reproductively dormant animals, undifferentiated spermatogonia failed to differentiate and accumulated in the seminiferous tubules. RNA-seq analyses of the active and dormant testes revealed that genes modulating retinoic acid biogenesis and steriodogenesis were differentially regulated. A single injection of all-trans retinoic acid (ATRA) reinitiated spermatogenesis and inhibition the function of RA-degrading enzyme CYP26B1 for 10 days induced spermatogonial differentiation. Strikingly, testosterone injection reinitiated spermatogenesis in short day adapted animals. Testosterone provides a permissive environment of RA biogenesis and actions in testis, therefore, indirectly controls spermatogonial differentiation. Collectively, these findings provide a key mechanistic insight regarding the molecular regulation of seasonal reproduction in mammals.

The gut microbiota in mammals plays a key role in host metabolism and adaptation. However, relatively little is known regarding to how the animals adapts to extreme environments through regulating gut microbial diversity and function. Here, we investigated the diet, gut microbiota, short-chain fatty acid (SCFA) profiles, and cellulolytic activity from two common pika (Ochotona spp.) species in China, including Plateau pika (Ochotona curzoniae) from the Qinghai-Tibet Plateau and Daurian pika (Ochotona daurica) from the Inner Mongolia Grassland. Despite a partial diet overlap, Plateau pikas harbored lower diet diversity than Daurian pikas. Some bacteria (e.g., Prevotella and Ruminococcus) associated with fiber degradation were enriched in Plateau pikas. They harbored higher gut microbial diversity, total SCFA concentration, and cellulolytic activity than Daurian pikas. Interestingly, cellulolytic activity was positively correlated with the gut microbial diversity and SCFAs. Gut microbial communities and SCFA profiles were segregated structurally between host species. PICRUSt metagenome predictions demonstrated that microbial genes involved in carbohydrate metabolism and energy metabolism were overrepresented in the gut microbiota of Plateau pikas. Our results demonstrate that Plateau pikas harbor a stronger fermenting ability for the plant-based diet than Daurian pikas via gut microbial fermentation. The enhanced ability for utilization of plant-based diets in Plateau pikas may be partly a kind of microbiota adaptation for more energy requirements in cold and hypoxic high-altitude environments.

Understanding a species' functional traits allows for a directed and productive perspective on the role a species plays in nature, and thus its relative importance to conservation planning. The functional-trait ecology of the plateau pika Ochotona curzoniae is examined to better understand the resilience and sustainability of the high alpine grasslands of the Qinghai-Tibetan Plateau (QTP). The key functional traits of plateau pikas are their abundance and behavior of digging extensive burrow systems. Plateau pikas have been poisoned over a significant part of their original geographic distribution across the QTP, allowing comparison of ecological communities with and without pikas. Nearly all mammalian and avian carnivores, most of which are obligate predators on pikas, have been lost in regions where pikas have been poisoned. Most endemic birds on the QTP nest in pika burrows; when pikas are poisoned, burrows collapse, and these birds are greatly reduced in number. Due to the biopedturbation resulting from their burrows, regional plant species richness is higher in areas with pikas than without. The presence of pika burrows allows higher rates of infiltration during heavy monsoon rains compared to poisoned areas, possibly mitigating runoff and the potential for serious downslope erosion and flooding. Thus, the functional traits of plateau pikas enhance native biodiversity and other important ecosystem functions; these traits are irreplaceable. As plateau pikas are not natural colonizers, active re-introduction programs are needed to restore pikas to areas from which they have been poisoned to restore the important functional ecological traits of pikas.

Burrows serve many functions for animals by providing a place for rearing young, sleeping, hibernation, food storage, protection from predators and extreme environment, and the function of burrows varies with the degree of burrow complexity. We studied the burrow architecture (length, internal dimensions, fractal dimension of tunnel systems, number of nesting chambers and surface holes) by excavating the tunnels of 24 burrow systems of the plateau pika (Ochotona curzoniae). Pikas have two types of burrow systems, namely temporary and permanent burrows. The number of surface holes and length of tunnels were significantly different between the temporary and permanent burrows. Tunnel width and tunnel height were not significantly different between the temporary and permanent burrows. The permanent burrow had a nesting chamber but temporary did not have any. No hoarding chamber was found in either the permanent or the temporary burrow. The temporary burrow was used to avoid predators in emergency situations, and probably was the initial stage of construction of more complex burrows of some dispersing pikas. Permanent burrows were used for avoiding predators, resting and rearing offsprings.

Plateau pikas (Ochotona curzoniae), burrowing lagomorphs endemic to the Qinghai-Tibetan Plateau (QTP), are considered pests by Chinese authorities because of their association with grasslands that are characterized as degraded. Officials typically blame pikas for causing the degraded conditions, whereas studies increasingly suggest that sparse vegetation encourages population growth and high densities of pikas. Correlational investigations that document pika density while simultaneously describing grassland conditions can quantify this association, but are uninformative regarding causation. We used livestock exclosures and pika reductions in partially controlled experiments to examine how pika habitat use responds to changes in vegetation structure caused by wintertime livestock grazing. Mean counts of pikas were higher on grazed than ungrazed plots. Linear models accounting for experimental pika reduction as well as seasonal phenology indicated that grazing significantly increased pika use compared with ungrazed plots. These results show that moderate livestock density is likely consistent with both biodiversity conservation and economic activity, and that high pika populations alone are not responsible for observed degradation of the QTP alpine grasslands. Moderate levels of livestock grazing and pika presence are consistent with maintaining the integrity of the alpine steppe ecosystem of the QTP.

The foraging and burrowing activities of small mammalian herbivores may have either detrimental or beneficial effects on grassland ecosystems; the direction of the effect is determined by the species, population abundances and fluctuations. Twelve survey sites with active burrow of plateau pika were classified into four degrees of density: approximately zero-density, low-density, medium-density and high-density, to evaluate the impact of different pika densities on vegetation, plant biomass, soil organic carbon and nutrients in a whole growing season. We show that pika as a main supplement to livestock activities contributed to a decrease in the number of plant species, vegetation cover, plant height and seasonal mean biomass, while values at medium-density site except above-ground biomass were the lowest. With the exception of available potassium, soil organic carbon, nitrogen, total phosphorus and soil water content, zero-density areas were significantly higher than those of pika occupied areas. However, there were slight or no differences in vegetation characteristics and soil properties between medium-and high-density sites. Our study suggests pika activities with high-density made palatable forage less and soil carbon and nitrogen more than low-density, moreover, plateau pika had greater impacts on above-ground vegetation than on root system.

Pikas ( Ochotona curzoniae ) are common on the Qinghai-Tibetan Plateau (QTP). However, little is known about the effect of their burrowing activity on carbon emissions from alpine grassland ecosystems. In this study, we investigated soil organic carbon (SOC), total nitrogen (TN) density and ecosystem CO 2 flux from the original vegetation and pika piles of three typical alpine grasslands in two climate regions. SOC loss induced by pika activity varied among grassland types. Alpine meadow with high SOC was susceptible to pika activity. Ecosystem CO 2 flux from pika piles with open holes was significantly higher than that from the original vegetation ( P n = 4). When holes near pika piles were blocked, ecosystem CO 2 flux from pika piles was not significantly different from that of the original vegetation ( P > 0.05, n = 4). Our results suggested that CO 2 dissipates into pika tunnels and is easily emitted into the atmosphere through pika holes. Due to the large amount of pika holes in alpine grasslands, their significant effect on ecosystem CO 2 flux should not be ignored in future studies.

The objective of this study was to compare the different ventilatory strategies that help in coping with hypoxic-hypercapnia environment among two species: use acclimated rats and plateau pikas (Ochotona curzoniae) that live in Tibetan plateaus, and have been well adjusted to high altitude. Arterial blood samples taken at 4100 m of elevation in acclimatized rats and adapted pikas revealed inter-species differences with lower hemoglobin and hematocrit and higher blood pH in pikas. A linear and significant increase in minute ventilation was observed in pikas, which help them to cope with hypoxic-hypercapnia. Pikas also displayed a high inspiratory drive and an invariant respiratory timing regardless of the conditions. Biochemical analysis revealed that N-methyl-D-aspartate receptor (NMDA) receptor gene and nNOS gene are highly conserved between rats and pikas, however pikas have higher expression of NMDA receptors and nNOS compared to rats at the brainstem level. Taken together, these results suggest that pikas have developed a specific ventilatory pattern supported by a modification of the NMDA/NO ventilatory central pathways to survive in extreme conditions imposed on the Tibetan plateaus. These physiological adaptive strategies help in maintaining a better blood oxygenation despite high CO2 concentration in burrows at high altitude.

LDH-C4 is a lactate dehydrogenase that catalyzes the conversion of pyruvate to lactate. In mammals, ldh-c was originally thought to be expressed only in testis and spermatozoa. Plateau pika (Ochotona curzoniae), which belongs to the genus Ochotona of the Ochotonidea family, is a hypoxia tolerant mammal living 3000–5000 m above sea level on the Qinghai-Tibet Plateau, an environment which is strongly hypoxic. Ldh-c is expressed not only in testis and sperm but also in somatic tissues of plateau pika. In this study, the effects of N-propyl oxamate and N-isopropyl oxamate on LDH isozyme kinetics were compared to screens for a selective inhibitor of LDH-C4. To reveal the role and physiological mechanism of LDH-C4 in skeletal muscle of plateau pika, we investigated the effect of N-isopropyl oxamate on the pika exercise tolerance as well as the physiological mechanism. Our results show that Ki of N-propyl oxamate and N-isopropyl oxamate for LDH-A4, LDH-B4, and LDH-C4 were 0.094 mmol/L and 0.462 mmol/L, 0.119 mmol/L and 0.248 mmol/L, and 0.015 mmol/L and 0.013 mmol/L, respectively. N-isopropyl oxamate is a powerful selective inhibitor of plateau pika LDH-C4. In our exercise tolerance experiment, groups treated with inhibitors had significantly lower swimming times than the uninhibited control group. The inhibition rates of LDH, LD, and ATP were 37.12%, 66.27%, and 32.42%, respectively. Our results suggested that ldh-c is expressed in the skeletal muscle of plateau pika, and at least 32.42% of ATP in the skeletal muscle is catalyzed by LDH-C4 by anaerobic glycolysis. This suggests that pika has reduced dependence on oxygen and enhanced adaptation to hypoxic environment due to increased anaerobic glycolysis by LDH-C4 in skeletal muscle. LDH-C4 in plateau pika plays the crucial role in anaerobic glycolysis and generates ATP rapidly since this is the role of LDH-A4 in most species on plain land, which provide evidence that the native humans and animals in Qinghai-Tibet plateau can adapt to the hypoxia environment.

The results in this study show the prevalence of Yersinia enterocolitica varies in different animal species and regions of China. The highest prevalence is among pigs (12.91%), followed by dogs (9.80%), Ochotona curzoniae (plateau pica) (6.76%), chickens (4.50%), rodents (3.40%), cattle (2.78%) and sheep (0.89%). Pathogenic isolates comprised the majority of the Y. enterocolitica recovered from pigs (73.50%) and dogs (59.44%); whereas the nonpathogenic Y. enterocolitica made up most of poultry and wildlife recovered strains. A correlation analysis comparing the prevalence and geographic factors showed the isolation rate of Y. enterocolitica in pigs and dogs was negatively correlated with elevation (r=-0.50, P

The plateau pika has developed tolerance to cold and hypoxia in order to adapt to living in the extreme environment of the Qinghai-Tibetan Plateau. One mammalian mechanism for cold adaptation is thermogenesis by brown adipose tissue (BAT), but the degree to which pika exploits this mechanism or how it may be modified by the additional stresses of high altitude is not known. Intermittent Cold Exposure (ICE) is an approachable method to study cold adaptation in rodents. To investigate the role of adipose tissue in the adaptation of pika to cold temperatures, we have studied pika during ICE. We find that pika kept in warm temperatures has little classical brown fat, but "browning" of white adipose tissues is observed rapidly upon cold exposure. This is demonstrated by the increased expression of several markers of brown fat differentiation including uncoupling protein 1 (UCP-1). Surprisingly, this occurs mainly in visceral rather than epididymal adipose tissue. In addition, ICE increases the expression of several general adipose differentiation markers at both the mRNA and protein levels. These substantial changes in the distribution of fat are accomplished without changes in weight or blood levels of glucose and triglycerides, suggesting that the adaptable changes are coordinated and self-compensated. Together, our results demonstrate that ICE promotes recruitment of BAT in pika, and unlike small mammals in at lower altitudes, pika can activate visceral WAT to adapt to cold stress without major changes overall energy balance.

The Oriental Skylark Alauda gulgula is a widespread species, but its natural history is poorly understood, especially at high altitudes. In this study, we collected breeding information on Oriental Skylarks at an altitude of 3,400 m on the northeastern part of the Tibetan Plateau and examined the effects of nest-site characteristics on nest success. The birds arrived in the study area in April, built nests in tufts of tall grass on the ground and laid their eggs (gray with brown speckles) between May and July. Clutch size averaged 3.3 eggs. Incubation was mainly by the female and lasted 12.4 days. The young left the nest when 9.7 days old. During the breeding season, individual skylarks made 2–3 breeding attempts. Nesting success, as measured by the proportion of nests from which at least one young fledged, was 41.3%. Predation accounted for the majority of failed nests. Some predators (e.g. carnivores) took both skylarks and Mountain Pikas Ochotona curzoniae, although the pikas, as the dominant ...

The Tibetan fox (Vulpes ferrilata) is generally acknowledged to be a specialist forager on its preferred prey, the burrowing lagomorph plateau pika (Ochotona curzoniae), but whether true dependency characterizes the relationship remains unclear. We estimated the presence of Tibetan foxes in 62 habitat patches that reflected a continuum of environmental conditions within their known geographic distribution within Qinghai Province, China. We used site-occupancy modeling and quantified the abundance of plateau pikas as well as other site variables that could plausibly predict fox presence. We quantified fox presence by collecting and sequencing DNA from scats. The number of pikas and the number of their burrows were the only covariates supported in predictive models of Tibetan fox presence. The probability of site occupancy by foxes increased with pika abundance, and was close to 0 when pikas were absent even within habitat patches otherwise generally suitable. DNA-based diet analysis also allowed us to identify prey species consumed by Tibetan foxes. Approximately 99% of fox scats contained pika DNA sequences, 97% contained predominantly pika sequences, and 73% contained only pika sequences. We conclude that Tibetan foxes in this region are not merely foraging specialists of plateau pikas, but that they are obligate predators on pikas. Plateau pikas, while presently still abundant on the Qinghai-Tibetan Plateau, are considered a pest by government policy and are subject to extensive, government-funded poisoning programs. The Tibetan fox is currently at no substantial risk as a species, but this could change if pika poisoning increases in scope, intensity, or effectiveness.