Evidence That the Tibetan Fox Is an Obligate Predator of the Plateau Pika: Conservation Implications

Journal of Mammalogy, 95(6):1207–1221, 2014

Evidence that the Tibetan fox is an obligate predator of the plateau pika: conservation implications

RICHARD B. HARRIS,ZHOU JIAKE,JI YINQIU,ZHANG KAI,YANG CHUNYAN, AND DOUGLAS W. YU* Department of Ecosystem and Conservation Sciences, University of Montana, 32 Campus Drive, Missoula, MT 59812, USA (RBH, ZJ) Ecology, Conservation, and Environment Center (ECEC), Kunming Institute of Zoology, #338, 32 Jiaochang East Road, Kunming, Yunnan, 650223 China (JY, ZK, YC, DWY) School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR 47TJ, United Kingdom (DWY) * Correspondent: [email protected]

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.

Key words: China, obligate predator, occupancy, Ochotona curzoniae, pest, specialist, Tibetan plateau, Vulpes ferrilata

Ó 2014 American Society of Mammalogists DOI: 10.1644/14-MAMM-A-021

That species differ in their degree of specialization, canonical example of an obligate predator is the black-footed particularly with regard to diet, is a fundamental and accepted ferret (Mustela nigripes), a highly endangered mustelid of the tenet of ecology (Hanski et al. 1991). The continuum between North American Great Plains, which is so specialized a generalized and specialized foragers is useful to both predator of fossorial rodents in the genus Cynomys that it researchers and conservation practitioners, with specialists cannot live without them (Hillman and Clark 1980; Biggins et generally being acknowledged as more sensitive to habitat al. 2006). alterations or reductions than generalists (Owens and Bennett However, characterizing a species as obligatorily dependent 2000; Ryall and Fahrig 2006), and thus more likely to be of on another is easier to do in theory than in the ﬁeld. Recently, a conservation concern. The end point of specialization is number of studies have documented cases in which a predator, represented by species that are so reliant on another single seemingly narrowly focused on a particular prey species in species that the former cannot persist without the latter. In some geographic areas, habitats, or circumstances, turns out predator–prey relations, extreme specialist predators are called obligate predators or, alternatively, obligate associates. In short, the presence of a single prey species (or group of similar species) makes possible the existence of the consumer. A www.mammalogy.org 1207

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upon further investigation to be more flexible than earlier difficulty of conducting them throughout the focal species’ believed. For example, in contrast to suggestions that the wild range, so it is always possible that the relationship holds where cat (Felis silvestris), while normally a generalist, had adapted studied but not elsewhere. to the abundance of the rabbit Oryctolagus cuniculus in the In theory, the strongest evidence of an obligate predator Iberian Peninsula by becoming a local specialist, Malo et al. association would come from experimental removal studies (2004) demonstrated flexibility among cat diets, suggesting (approach 4, above). However, aside from the considerable that specialization was facultative rather than fundamental. ethical problems posed by removing an entire population Eurasian badgers (Meles spp.), sometimes forage specialists on merely to observe the consequences to another, an experimen- a local scale, have been found to be generalists when viewed at tal approach also would confront considerable logistical a global scale (Li et al. 2013). challenges for its advantages over observational data to be We can conceive of 4 nonexclusive approaches investigators realized. Experimental removal of prey would be required over might adopt to assess the hypothesis that a predator species is a large geographic and temporal scale to ensure that any entirely dependent on a particular prey, with the strength of predator response would be detected and caused by the evidence increasing in the following order: 1) dietary studies, removal rather than extraneous factors. We are not aware of showing the predator foraging exclusively (or nearly so) on the attempts to conduct such experiments in realistic field settings. prey; 2) distributional studies at a coarse scale, showing that Notwithstanding the difficulties of its documentation in the the distribution of the predator is nested (or nearly so) within field, knowledge that a species is highly or entirely dependent that of the prey; 3) occupancy studies at a finer geographic on another is crucial for effective conservation planning. In scale, showing that presence of the predator is strongly North America, the conservation of black-footed ferrets has predicted by presence of the prey while no evidence supports become inextricably linked with the social and political issues alternate hypotheses investigated at the same sites; and 4) surrounding its rodent prey, which although not nearly as rare, experimental studies, in which removal of the prey species have also declined precipitously from historic abundances due causes extirpation of the predator species. largely to the rodents’ perceived roles as agricultural pests A primary weakness of most dietary studies (approach 1, (Miller et al. 1996, 2007; Biggins et al. 2006). Similarly, above) is that they are site-specific: it is always possible that a conservation needs of the Canada lynx (Lynx canadensis)in predator exhibiting extreme specialization in the system under North America, particularly toward the southern extent of its study may behave in a more generalized way or specialize on geographic range, have implicated forest practices bearing on alternative species in situations not yet studied. In such cases, habitat suitability for its primary prey, snowshoe hares (Lepus dietary evidence could support the hypothesis that the predator americanus—Koehler 1990; Squires and Ruggiero 2007; exhibits facultative specialization, but not necessarily that it is Simons-Legaard et al. 2013). In Florida, snail kites (Rostrha- an obligate predator. However, a strength of dietary studies is mus sociabilis plumbeus), which specialize on a single species that they can be replicated across numerous study areas, with of snail (Sykes 1987), may be negatively affected by the evidence of the obligatory nature of the relationship increasing invasion of a nonnative snail that the kite now also consumes, as data from multiple study sites accumulates. but at a greater energetic cost (Cattau et al. 2010). Finally, Investigations into geographic overlap (approach 2, above) Terraube et al. (2011) provided evidence that reproductive suffer from the usual weakness of correlational studies, that is, success among pallid harriers (Circus macrourus) breeding in they cannot rule out the possibility that unstudied factors are central Asia was linked to the abundance of their preferred the true causes of overlap. If both species respond to microtine rodent prey. environmental factors other than each other, the evident The Tibetan fox (Vulpes ferrilata) is a little-studied relative association could be spurious. That said, it should generally of the abundant generalist, the red fox (V. vulpes). Restricted be possible to identify those unusual situations resulting in a geographically to treeless habitats of the Qinghai-Tibetan tight nesting of the predator’s distribution within that of the Plateau, generally at elevations exceeding 3,500 m (Clark et al. prey other than the presence of the prey itself (e.g., cavities in 2008; Wozencraft 2008), Tibetan foxes share with their red fox trees made by a 3rd species). If none such can be identified congeners many behavioral characteristics, such as biparental based on natural history, and particularly if multiple dietary care, digging extensive whelping dens, and using daytime studies (approach 1, above) support specialized foraging, a shelters to reduce predation risk (Schaller and Ginsberg 2004; nested geographic distribution of the higher- on the lower- Clark et al. 2008). However, in marked contrast to the trophic-level species tends to suggest an obligatory relation- cosmopolitan red fox, Tibetan foxes have generally, if so far ship. uncritically, been characterized as a foraging specialist We view the prediction of predator on prey presence from (Schaller et al. 2008). In particular, Tibetan foxes seem to occupancy studies (approach 3, above), if conducted at the prey predominantly, albeit not exclusively, on plateau pikas appropriate spatial scale, as stronger evidence than either of the (Ochotona curzoniae), the common colonial, grassland-dwell- above 2 approaches. Such studies can better account for a suite ing lagomorph of the Qinghai-Tibetan Plateau (Zheng 1985; of plausible hypotheses explaining the predator’s presence, and Schaller 1998; Gong and Hu 2003). While adept at capturing are a based on well-understood statistical properties. Similarly plateau pikas (hereafter pikas—Wang et al. 2004), Tibetan to dietary studies, occupancy studies suffer from the logistical foxes also are known to engage in a modified type of

kleptoparasitism, in which they capture pikas excavated but not geographic distribution, with reference to a suite of niche- captured by brown bears (Ursus arctos—Harris et al. 2008). In related variables that we hypothesized could constrain the fox’s many areas of the Qinghai-Tibetan Plateau, pikas are subject to ability to form self-sustaining populations (approach 3, above). poisoning policies that have generated conservation concern We used occupancy modeling (MacKenzie et al. 2006) to (Smith and Foggin 1999; Smith et al. 2006; Delibes-Mateos et assess the strength of covariates to explain Tibetan fox al. 2011). If Tibetan foxes depend entirely on the presence of presence. We reasoned that if Tibetan foxes were truly obligate these pikas, the implications for conservation of the foxes are associates of plateau pikas, we would routinely find them more direct than if their preference for pikas as prey is merely where pikas were abundant, occasionally find them where facultative. pikas were rare, and fail to find them altogether where pikas Although existing literature clearly paints a picture of close were absent but alternative were prey present. Because the association between the Tibetan fox and plateau pikas, to date approach of MacKenzie et al. (2006) explicitly incorporates the no published studies have been designed to specifically test the probability of detection at each site, it allowed us to avoid the hypothesis that Tibetan fox populations cannot persist in the pitfalls of inference based on the (almost certainly incorrect) absence of pikas. Wang et al. (2007) showed that Tibetan fox assumption of perfect detection. We recognized, however, that sign was more likely to be found in steppe than shrub habitat, our design relied on correlation rather than controlled and they interpreted this as further evidence of the dependence experiment, and was therefore vulnerable to erroneous of the foxes on pikas (which rarely colonize shrubby areas— inference caused by unmeasured variables. Thus, we also Jiang 1988; Smith et al. 1990). However, the study sites quantified or documented a suite of alternative factors that investigated by Wang et al. (2007) were dictated by areas in could plausibly provide alternative explanations of Tibetan fox which radiomarked Tibetan foxes had established home ranges, presence and absence at each site. thus limiting the scope of inference to the 3rd-order scale of Because Tibetan foxes are crepuscular and reclusive (Clark selection (sensu Johnson 1980). Similarly, based on radio- et al. 2008), we anticipated that sample sizes for occupancy tracking of 6 Tibetan foxes, Liu et al. (2007) documented a analyses would be small if we depended on direct observation weak, albeit significantly positive relationship between fox to document presence. Thus, we quantified Tibetan fox site activity and relative pika abundance at the scale of the home occupancy through sampling of fox feces (hereafter scats). range. However, pikas were present in all portions of the home Because confident discrimination of scats from foxes and other ranges of all foxes, and unmarked foxes maintained home possible species in the area was not possible based solely on ranges beyond the boundaries of the radiomarked individuals. field observation, we collected scats and identified them to Thus, although consistent with an association between the species using a species-diagnostic fragment of the 16S rRNA predator and prey, the design of this study prevented Liu et al. gene (see also Jiang et al. 2011). (2007) from drawing strong conclusions regarding the importance of pikas to foxes. Dietary analyses using macroscopic inspection of prey MATERIALS AND METHODS remains from feces have consistently shown that Tibetan fox Study area.—Sample sites were chosen to represent habitats diets are dominated by pikas (Zheng 1985; Schaller 1998:186; characteristic of the Qinghai-Tibetan plateau steppe and Liu et al. 2010); these studies have only been conducted where meadow within Qinghai Province, China, at elevations of the 2 species are common. However, where extermination approximately 3,400–4,700m. Following the example of Lai programs targeting pikas have not been initiated (or have been and Smith (2003), we selected sites in 12 townships within ineffective), and particularly where rangelands have been Qinghai, representing the counties of Chengduo, Dulan, disturbed to the point where vegetation height is reduced and Gangca, Gonghe, Guinan, Maqin, Menyuan, Nangqian, bare ground is common (often via overgrazing by livestock), Qilian, Tongde, Yushu, and Zeku (Fig. 1). All sites were pikas can attain very high densities. Thus, if dietary studies of grazed at some time during the year by flocks of sheep (Ovis Tibetan foxes are situated where pikas are common, simply aries), herds of yaks (Bos grunniens), and less commonly, finding that they consume primarily pikas may not necessarily horses (Equus caballus). At elevations . 4,200 m, habitats indicate ecological dependency; it may merely reflect optimal were primarily mesic alpine meadows, consisting of a dense foraging. It remains unclear whether Tibetan foxes might have mosaic of graminoids and dicots, but dominated by sedges in the capability to switch to alternative prey in the absence of the genus Kobresia. At elevations , 4,200 m, habitats were pikas, or whether they can successfully maintain populations in generally more xeric steppe, largely made up of grasses such as areas devoid of pikas. Stipa, Leymus, and Poa, with associated dicots. Here, we provide evidence of the obligatory nature of the In addition to the Tibetan fox, mammalian carnivores within predator relationship of Tibetan foxes on plateau pikas. We these steppe and meadow habitats in Qinghai included wolf supplement existing information on dietary specialization (Canis lupus), red fox (V. vulpes), Eurasian lynx (Lynx lynx), (approach 1, above), and clarify the geographic distribution mountain cat (Felis bieti), Pallas’s cat (Otocolobus manul), of the fox (approach 2, above), examining the degree to which Eurasian badger (Meles leucurus), steppe polecat (Mustela it is nested within that of the pika. We present new data on site eversmanii), Altai weasel (Mustela altaica), and brown bear occupancy of Tibetan foxes within a substantial portion of their (U. arctos). The Asian wild dog (Cuon alpinus) is listed as

FIG.1.—Study area, showing locations of sites (small dots) sampled for occupancy of Tibetan foxes (Vulpes ferrilata) within Qinghai Province, October–December 2011, in relation to the estimated geographic range of the Tibetan fox (thick line [from Schaller et al. 2008]). Also shown are major cities in the area (stars).

present in these areas by many Chinese species lists, but if not International Union for Conservation of Nature (IUCN) extirpated, is extremely rare (Harris 2008). The Tibetan fauna Species Survival Commission (SSC) Red List Web site includes a number of wild ungulate species, but only the (IUCN 2014). We used information on the natural history of Tibetan gazelle (Procapra picticaudata) was likely to be Tibetan foxes not available to Schaller and Ginsberg (2004) common at the study sites investigated here. Smaller mammals when they developed the fox map adopted by IUCN/SSC to present and previously reported as consumed by Tibetan foxes further refine it on the basis of lower elevation limit, and include Himalayan marmots (Marmota himalayana), the quantified the proportion of the fox map nested within the pika fossorial rodent plateau zokor (Eospalax fontanierii—Zhang map using ArcGIS 10.1 (ESRI Environmental Systems et al. 2003b), jerboas (Allactaga sibirica), mountain voles Research Institute [ESRI] 2011). (Neodon spp.), voles (Microtus spp. and Lasiopodomys spp.), Field protocols.—During 5 field trips beginning on 6 and dwarf hamsters (Cricetulus spp.). October and extending through 1 December 2011, we Geographic distribution.—Maps of the distribution of searched for Tibetan fox scats on 62 subjectively selected Tibetan foxes and plateau pikas based on site-specific and sites within Qinghai Province, China. We required of each site geographically referenced data are lacking. Thus, we examined that it be located generally within the overall geographic the best available range maps, those produced by the distribution both of the Tibetan fox and the plateau pika

(Schaller et al. 2008; Wozencraft 2008); characterized by earth mounds created by zokors. Within each plot we estimated habitat generally recognized as suitable for both Tibetan foxes proportion covered by vegetation (i.e., neither bare ground nor and pikas (e.g., alpine meadow or steppe, lack of substantial rock) visually in 10% increments, and measured the predom- shrubby vegetation or forest cover, and neither excessively inant vegetation height with a handheld ruler. swampy nor rocky); sufficiently distant from substantial human Upon completion of the survey, each site also was settlements, highways (. 1 km), or other sources of characterized qualitatively as follows. We categorized the disturbance that might otherwise function to deter small prevailing habitat type, defined as alpine meadow dominated 2 native carnivores; large enough (generally ~4km) to have a by sedges of the genus Kobresia; alpine steppe, dominated by nonnegligible probability of fox occurrence if the habitat was grasses such as Stipa spp.; or undifferentiated weedy, appropriate, yet homogenous enough to be characterized and dominated by annual forbs. Pasture was categorized as used differentiated from all others; no closer than 4 km to the next by livestock either in summer, or winter, as evidenced by the nearest site; and accessible from a vehicle and traversable on observation of winter camps or information provided by local foot. Within each site we surveyed 4 regularly spaced 500-m- residents. The relative amount of human presence at the site long transects. Each transect was treated as a subsurvey (i.e., K was categorized as low, moderate, or high, based on ¼ 4), effectively substituting space for time to generate proximity to houses or settlements (typically 1 or 2 small detection histories (MacKenzie et al. 2006:162). Although houses, 0.5- to 5-km distant). The relative density of roads our resampling was without replacement, the high mobility of (generally consisting of 1 or 2 rough, unpaved rural tracks) Tibetan foxes (Liu et al. 2007) relative to the geographic scale was categorized as low, moderate, or high. The relative of our sites (and the fact that scats reflected presence over some abundance of standing water (e.g., streams or ponds) was extended temporal scale) rendered our design safe from the characterized as low, moderate, or high. The presence or concerns related to lack of closure expressed by Kendall and absence of livestock during the survey period also was White (2009:1186). documented. After identifying that these general restrictions were To characterize our ability to detect carnivore scats actually satisfied, transect direction was determined based on an present, we recorded the beginning and ending time of each orientation that would provide for the 4 parallel transects survey; weather conditions (qualitatively categorized as sunny, while maintaining homogeneity of habitat characteristics, as overcast, windy, raining, or snowing); presence or absence of observed visually at each site. The precise initial starting point snow cover on the ground; and a generalized index variable for the 1st transect was located by blindly tossing a rock or that captured the survey crew’s impression of their ability to similar object, and recording where it landed using a handheld detect any scats present during the survey. Because in our case, global positioning system. We then identified a distant detection probability involved not merely our ability to find landmark corresponding to the chosen azimuth, walking scats in the field but also of extracting DNA for species toward it while searching the ground on both sides for scats identification and because success of species-level identifica- that could plausibly have been produced by a mammalian tion from DNA extracted from fecal material is often carnivore and documenting the number of paces walked from the beginning. All transects were surveyed by the same 2- negatively correlated with surface moisture on the scat (Farrell person crew. While 1 person focused his attention on the et al. 2000; Piggott 2004), we also documented whether ground for scats (generally within 5 m on either side), the other moisture from the environment was evident on the scat’s scanned more widely (to approximately 30 m on each side), surface. looking for pikas active aboveground. All pikas seen while To avoid cross-contamination, scats were immediately walking transects were recorded. Upon finding a possible transferred to 30-ml free-standing centrifuge tubes (Evergreen carnivore scat, 1 person remained on the transect line while the Scientific, Los Angeles, California) using supplied plastic other collected it (see below). Upon reaching the end of the ‘‘sporks.’’ Tubes were filled with 95% ethanol atop silica gel transect line (as indicated by the global positioning system), the orange-indicating desiccant beads (Silica Gel Products, Harris- crew travelled in a direction perpendicular (i.e., offset 908)to burg, North Carolina). Following fieldwork, tubes were stored the line for 0.5 km (without collecting scats or counting pikas) in an ultracold-temperature freezer (808C) at Qinghai Normal before beginning the subsequent line in the opposite direction University in Xining until being shipped in a cooler to the (i.e., offset 1808) from the initial orientation. This protocol was Kunming Institute of Zoology for DNA extraction, polymerase repeated until 4 parallel lines, totaling ~2 km, were searched. chain reaction amplification, and sequencing. To characterize each site by hypothesized determinants of DNA extraction and sequencing for scats.—Genomic DNA Tibetan fox occupancy, we recorded site elevation at the from scats was isolated at the Kunming Institute of Zoology beginning and terminus of each of the 4 transects (n ¼ 8/site). using the QIAamp DNA Stool Mini Kit (Qiagen, Hilden, At the beginning, end, and 200-pace (~150 m) intervals along Germany), according to manufacturer’s instructions. We used a each transect, we established a temporary plot of 5-m radius mammalian primer set, which were 16Smaml (forward primer) using a flexible tape (i.e., n ¼ 4/transect; n ¼ 16/site). Within 50-CGGTTGGGGTGACCTCGGA-30 and 16Smam2 (reverse this circle we developed indexes of pika and zokor density by primer) 50-GCTGTTATCCCTAGGGTAACT-30 (Taylor counting all evident burrows created by pikas, as well as all 1996), to amplify a short 16S rRNA fragment from the

samples. The length of the target fragment was about 90 base Tibetan fox was not in GenBank. We therefore obtained pairs (bp), not including the primer sequences. tissue of a Tibetan fox from the Qinghai-Tibet Plateau Because our objective was to identify both predators and Natural History Museum, Xining, Qinghai, Sanger their prey, we sequenced the amplicons using the GS FLX sequenced 413 bp of the 16S gene using the l2513 (50- System (454 Life Sciences: Roche Applied Science, Branford, GCCTGTTTACCAAAAACATCAC-30)and16S_LEECH_R1 Connecticut), to which we attached standard A and B Roche (50-TCTGCGAGGCTGTTATCCCTAGGGTAACT-30) adaptors and an 8-bp MID tag to the primer pair for each primers, and uploaded to GenBank (accession number sample. The structures of the forward and backward primers KC538826). We then BLASTed (blastn) the 268 OTUs were 50-adaptorA þ MID þ 16Smaml-30 and 50-adaptorB þ using default options in Geneious version 6.0.5 (Drummond 16Smam2-30. Polymerase chain reactions were performed in et al. 2011). After removing invertebrates and non-16S 20-ll reaction volumes containing 2 ll of 10 buffer, 1.5 mM of OTUs, we documented 241 vertebrate 16S OTUs. We MgCl2, 0.2 mM of deoxynucleoside triphosphates, 0.4 lMof filtered out BLAST hits that had less than 97.7% pairwise each primer, 0.6 U of exTaq DNA polymerase (TaKaRa Bio, identity and 1 identification of 38.4% query coverage. Inc., Otsu, Shiga, Japan), and 1–3 ll of genomic DNA. The Finally, as a check of the top BLAST hit per OTU, we also thermocycling profile was 958C for 5 min; 40 cycles of 958C assigned taxonomies using SAP 1.0.12 (Munch et al. 2008), for 12 s; 598C for 30 s; 728C for 1 min; then a final extension of which constructs 10,000 phylogenetic trees with the query 728C for 7 min. For sequencing, all the polymerase chain sequence and its GenBank homologues, and assigns a reaction products were gel-purified using Qiaquick Gel posterior probability of assignment for each query sequence Extraction Kit (Qiagen), quantified using the Quant-iT Pico- to each taxonomic rank (e.g., genus or family). We only Green dsDNA Assay kit (Invitrogen; Life Technologies, Grand accepted SAP assignments of . 80% posterior probability Island, New York), pooled and A-amplicon-sequenced on a (most were much higher), which resulted in most OTUs 454, using 3 separate one-eighth regions of a plate. being assigned to family or genus. We visually confirmed The DNA extraction and polymerase chain reaction were taxonomic consistency between the BLAST and SAP performed in separate rooms, and none of the amplified species assignments. had been present in the Kunming Institute of Zoology within at The number of reads assigned to a given OTU varied from 1 least the last decade, if ever. Samples were all extracted before to 1,359. Although read number per OTU is far from a precise any were amplified, and all polymerase chain reaction measure of biomass, read number is roughly positively preparation was conducted in an environment separate from correlated with biomass. We used a Microsoft Excel pivot the post–polymerase chain reaction stage. table to pool the reads for OTUs that were within the same Bioinformatic pipeline.—We employed the QIIME 1.6.0 fecal sample and received the same taxonomic assignment software environment (Caporaso et al. 2010) and BLASTed (Supporting Information S1, DOI: 10.1644/14-MAMM-A-021. (Altschul et al. 1990) to GeneBank (Benson et al. 2009) to S1). The 60,842 total reads in our data set ended up partitioned identify species from the sequence data obtained from each over 388 pooled OTUs, assigned to 17 species and the 148 scat. Within QIIME 1.6.0, header (MID and primer) sequences and low-quality reads were removed from the raw sequencing fecal samples (Supporting Information S1, table), including 1 data using the split_libraries.py script in QIIME 1.6.0. Each sample that contained an OTU of domestic pig (122 reads) and read was assigned a sample based on its MID sequence. 1 of human (49 reads), which we interpret as a human-derived Settings were minimum length 100, maximum length 250, sample. The other 17 human-assigned clusters contained maximum homopolymer length 9, maximum primer mismatch between 1 and 6 reads, suggesting only light contamination 2, barcode length 8, unassigned reads removed -r, reads by collectors or local residents. By far, most of the reads were without reverse primer removed -z truncate_remove. This step assigned to Tibetan fox (44,546 total reads, present in 145 of reduced 166,913 raw reads to 69,927 reads. Following this, the the 148 samples) and pika (13,847 reads, present in 146 output reads were denoised using the denoiser.py scrip in samples). QIIME with default settings, further reducing the number of In 47% of cases, only a single potential carnivore was reads to 68,316. identified at this step. For samples in which OTU data allowed We then used the UCHIME function of USEARCH 5.1 for . 1 possible predator (most often, both V. ferrilata and V. (Edgar 2010) to cluster the denoised output reads at 99% vulpes), we used a stringent protocol to filter assignments. similarity to detect and remove chimeric reads, which are When the OTU assigned to species ‘‘a’’ had a higher pairwise expected to be rare and should belong to small clusters. We identity than the OTU assigned to species ‘‘b,’’ and species ‘‘a’’ were left with 522 operational taxonomic units (OTUs ¼ received . 95% of the reads, we categorized the scat as clusters). We picked OTUs again at 98% similarity using produced by species ‘‘a.’’ When pairwise identity favored CROP 1.33 (Hao et al. 2011), which further reduced the species ‘‘b’’ over species ‘‘a,’’ we categorized the scat as number of OTUs to 268, and for each, we picked the longest produced by species ‘‘a’’ only if . 99% of the reads were of sequence as the OTU’s representative sequence. species ‘‘a.’’ Otherwise, the identity of species producing the Taxonomic assignment.—After all next-generation scat was categorized as ‘‘ambiguous,’’ and the scat was sequencing had been conducted, we discovered that the dropped from further analysis.

Occupancy modeling.—We approached modeling site meadow, 27 as grassland steppe, and 1 as undifferentiated occupancy as a 2-step process. First, we assumed simple weedy, dominated by annual forbs. We categorized 4 sites as models of occupancy (u) to develop a single best estimate of having moderate human presence, and the remainder as low. survey factors influencing detection (p) through examination of Rural road density was categorized as high on 5 sites, moderate a suite of models. We then used our best model of detection on 12, and low on the remaining 45. Water was categorized as factors to assess the strength of evidence for models of factors common at 4 sites, moderate at 1, and rare at the remaining 57. affecting occupancy. We examined a suite of plausible models Mean vegetation cover at sites varied from 4.7% to 91.9% (X¯ ¼ containing covariates that could influence occupancy (with a 54.6%, SD ¼ 18.9%), and mean vegetation height varied from logit-link function), assessing their strength by examining both 1.7 to 40.0 cm (X¯ ¼ 10.9 cm, SD ¼ 8.7 cm). Pikas observed at Akaike’s information criterion (AIC), as well as slope each site varied from 0 to 110/km (X¯ ¼ 23.5/km, SD ¼ 26.4/ coefficients and their associated SEs. Although we km). Our index of pika burrows varied from 0 to 48.6/site (X¯ ¼ documented all Tibetan fox scats collected and identified 17.7/site, SD ¼ 13.1/site). Zokor mound indexes varied from 0 (i.e., counts on each transect as opposed to simply detection, to 4/site (X¯ ¼ 0.21/site, SD ¼ 0.72/site). see Appendix I), we elected not to use the N-mixture Documentation of Tibetan foxes.—We walked a total of 132 abundance model (Royle 2004) to quantify determinants of km of transect lines searching for carnivore scats (X¯ ¼ 2.12 km/ occupancy because scats encountered within a given subsurvey site). A total of 169 scats were collected, of which 148 yielded were unlikely to be independent events, and because we had no DNA sufficient to generate confident species identification. way to quantify the relationship between number of fox scats Scats identified as Tibetan fox (n ¼ 135) averaged 2.18/site, and number of foxes. Thus, we used the single-species, single- and varied from 0 to 21/site. Thirteen scats were categorized as season model of MacKenzie et al. (2006) in program ambiguous and deleted from consideration; they included PRESENCE (Hines 2006) for all analyses. signals of V. vulpes, C. lupus, and Meles spp. Tibetan fox scats Although number of pikas seen/km2 and our index of were observed at 37 sites (na¨ıve estimate of site occupancy ¼ number of pika burrows/site were correlated (r ¼ 0.63, P , 0.597). 0.01), we justified including both in our models because they We encountered no Tibetan fox scats on sites where we reflected pika presence at different timescales. Pikas seen failed to observe pikas (n ¼ 10); we also encountered no fox reflected known presence on the date sites were sampled, but scats on sites where the mean number of pika burrows/site was we also examined models reflecting the possibility that foxes , 0.56 (n ¼ 5). The number of fox scats/site was a positive responded to a history of pika presence, which was more function of the number of pikas seen/km (least-squares linear reliably indexed by burrows that are retained on the landscape regression: fox scats ¼ 0.827 þ 0.057 (SE ¼ 0.016)*pikas seen/ 2 for . 1 year. We encountered a particular difficulty with the km, F1,60 ¼ 13.47; P ¼ 0.0005, adjusted r ¼ 0.17), and the variable ‘‘vegetation height,’’ which we hypothesized could mean number of pika burrows/plot (fox scats ¼ 0.865 þ 0.074 influence true occupancy, but also was likely to affect our (SE ¼ 0.034)*pika burrows/plot, F1,60 ¼ 4.84; P ¼ 0.032, ability to find carnivore scats. Further, previous work has adjusted r2 ¼ 0.07). shown that vegetation height (Fan et al. 1999) and a correlated Tibetan fox site occupancy.—Preliminary modeling characteristic, vegetation cover (Wangdwei et al. 2013), were indicated that our best prediction of Tibetan fox scat themselves negatively correlated with pika abundance. Some detection probability overall resulted from models containing preliminary models with vegetation height included in the 2 variables: whether or not snow was present on the ground, detection portion failed to converge if variables related to pikas and the time of day the survey began. Under a null model (as well as vegetation) also appeared in the occupancy portion, predicting occupancy, detection probability was positively making comprehensive comparisons difficult. Thus, we elected associated with having snow on the ground (b ¼ 1.047, SE ¼ to consider a series of primary models in which vegetation 0.436), and negatively associated with survey time of day (b ¼ height appeared only in the occupancy portion, but to explore 0.364, SE ¼ 0.173). Similar patterns were observed under all the possibility that its absence from the detection portion other models of occupancy. No other factors we considered distorted our results by means of additional, supplementary that might influence detection of scats (e.g., presence of wind, models. The most general model we examined showed no rain, clouds, livestock, and moisture on scats) were supported evidence of poor fit (bootstrapping, n ¼ 500, P . 0.2; i.e., cˆ , (AIC from 2 to 12 units higher). 1), thus we made no adjustment for overdispersion. Continuous The top AIC model of Tibetan fox occupancy included both variables were replaced by their standardized z transformations indexes of pika abundance (mean number of pikas seen/km, ((xi x¯)/SE(x)) to facilitate computation and interpretation. and number of pika burrows counted on 16 plots/site). One or both of the pika covariates appeared in all 7 of the top-ranking models (Table 1). In all cases, covariates representing pika RESULTS abundance were positive, and in most cases, magnitudes were Site characteristics.—Mean elevation of the 62 sites was approximately twice their SEs (Table 2). The best model 4,152 m (SD ¼ 378 m), and varied from 3,183 m at Haibei to lacking either of the pika variables included only vegetation 4,759 m at Zhiduo (Appendix I). All sites were identified as height, and was almost 13 AIC units higher than the top- winter livestock pasture; 34 were categorized as alpine sedge ranking model, and 6.6 AIC units higher than the least-

TABLE 1.—Site-occupancy models relating hypothesized explana- TABLE 2.—Coefficients for top patch occupancy models relating tory variables to the probability of Tibetan fox (Vulpes ferrilata) presence of Tibetan fox (Vulpes ferrilata) in 62 sites, Qinghai presence. All models used the same 2 covariates to model p, the Province, China, October–December 2011, to hypothesized explana- probability of detection given occupancy (snow on ground and time of tory variables. A) Top-ranking model. B) Top model (as in A) but survey beginning). Pika (Ochotona curzoniae) burrows ¼ mean including vegetation height as predictor of site occupancy. C) Top number of fresh pika burrows observed in 16 plots at each site; pikas model (as in A) but including vegetation height as predictor of seen ¼ number of pikas seen/km2 walked at each site; vegetation detection probability. Values are on the logit scale. u ¼ occupancy; p height ¼ site mean of 16 measurements taken at each site; vegetation ¼ detection. cover ¼ site mean of 16 measurements taken; elevation ¼ site mean of 8 measurements taken; human disturbance (reference level ¼ low); u p zokors (Eospalax fontanierii) ¼ number of zokor mounds counted in Estimate SE Estimate SE 16 plots at each site; habitat type (reference level ¼ steppe); livestock A) ¼ livestock present during survey (1 ¼ yes); (.) ¼ null model (no Intercept 4.677 2.140 0.597 0.198 explanatory covariates included). AIC ¼ Akaike’s information Pika burrows 2.873 1.421 criterion. k ¼ number of parameters. Pika seen/km 4.663 2.367 Begin survey 0.372 0.168 AIC Model Snow on ground 0.642 0.393 Model DAIC weight likelihood k B) u (z[pika burrows þ pikas seen]) 0.00 0.656 1.000 6 Intercept 4.245 2.127 0.578 0.198 u (z[pikas seen þ vegetation height]) 3.96 0.091 0.138 6 Pika burrows 2.568 1.495 u (z[pika burrows]) 4.39 0.073 0.111 5 Pika seen/km 4.232 2.370 u (z[pika burrows þ vegetation height]) 4.56 0.067 0.102 6 Vegetation height 0.326 0.646 u (z[pikas seen]) 5.00 0.054 0.082 5 Begin survey 0.374 0.168 u (z[pikas seen þ vegetation cover]) 6.08 0.031 0.048 6 Snow on ground 0.632 0.394 u (z[pika burrows þ vegetation cover]) 6.37 0.027 0.041 6 u (z vegetation height) 12.97 0.001 0.002 5 C) u (z vegetation height þ vegetation cover) 14.92 0.000 0.001 6 Intercept 5.235 2.660 0.596 0.393 u (vegetation cover) 20.37 0.000 0.000 5 Pika burrows 3.016 1.652 u (z[elevation]) 21.52 0.000 0.000 5 Pika seen/km 4.867 2.869 u (.) 29.55 0.000 0.000 4 Vegetation height 0.542 0.388 u (human disturbance) 31.14 0.000 0.000 5 Begin survey 0.331 0.165 u (z[zokors]) 31.40 0.000 0.000 5 Snow on ground 0.596 0.393 u (habitat type) 31.54 0.000 0.000 5 u (livestock) 31.54 0.000 0.000 5 Overall geographic distribution.—The IUCN/SSC maps of Tibetan fox (Schaller et al. 2008) and plateau pika (Smith and supported model containing a proxy for pika abundance. No Johnston 2008) suggested that approximately 84% of the other putative explanatory variables were supported. We geographic distribution of the Tibetan fox was nested within illustrate the relationship between the probability of Tibetan that of the plateau pika. However, the fox map produced by the fox occupancy and our index of pika burrows in Fig. 2 (using IUCN/SSC included areas very unlikely to be occupied. For back-transformed coefficients from the 3rd-ranking model example, the map included essentially all of Nepal, despite [Table 1]). The joint influence of pika burrows and pikas documentation that the Tibetan fox is known only from the observed is seen in Fig. 3 (using back-transformed coefficients Trans-Himalayan region in Mustang (Schaller et al. 2008; from the top-ranking model [Table 1]). Jnawali et al. 2011). Other large-sized areas which the map of To further examine the confounding influence of vegetation Schaller et al. (2008) considered occupied by Tibetan foxes but height, we added it both as a predictor of detection probability where Smith and Johnston (2008) did not map plateau pikas to our top model, and as an additional predictor of occupancy included parts of northeastern Qinghai, adjacent Gansu, and the (Table 2). In both cases, DAIC from the top model was , 2; extremely arid Qaidam Basin; in fact, these lack the Tibetan however, in neither case did we observe a substantial change in fox (Li 1989; Zheng 2003). Taking as a generous lower the positive coefficients relating the pika variables to fox elevation for the species the 3,000-m elevation contour (Fig. 4), occupancy, and in neither case was the ratio of the point our resulting distribution of the Tibetan fox was approximately estimate of vegetation height to its SE nearly as large as that for 2,021,064 km2, of which some 1,818,093 km2 (90%) were either pika variables. This suggested that although vegetation nested within the mapped distribution of the plateau pika. height affected our ability to detect fox scats, such detection Incidence of prey species in diets.—Of the 135 scats heterogeneity did not confound the positive association found confidently identified as Tibetan fox, 134 also contained with the pika variables. As well, the fact that the pika DNA from plateau pikas. The one that did not consisted coefficients remained similar with the addition of vegetation entirely of DNA from domestic yak. In 98 (73%) of the 134 fox height as a predictor of occupancy suggested that the main scats containing pika, pika was the sole prey species identified. information in these models was contained in the pika Species identified as minor components of Tibetan fox scats variables, rather than vegetation variables. (i.e., in addition to pika) included domestic yak (n ¼ 10),

FIG.2.—Probability of site occupancy by Tibetan fox (Vulpes ferrilata), as indexed by presence of scats. Qinghai Province, autumn 2011, as a function of an index of pika (Ochotona curzoniae) burrow abundance (see text). Coefﬁcients used are those from the 3rd-ranking model from Table 1. Shown are model point estimates (solid line) and upper and lower 95% conﬁdence limits (dashed lines).

domestic sheep (n ¼ 5), Marmota (n ¼ 4), domestic pig (n ¼ 3), not livestock were present, and the relative abundance of Eospalax (n ¼ 3), Neodon (n ¼ 3), Microtus (n ¼ 3), Cricetulus zokors all displayed no predictive ability to explain Tibetan fox (n ¼ 2), white-lipped deer (Przewalskium albirostris; n ¼ 2), occupancy. Other site variables could not be modeled because and Tibetan gazelle (n ¼ 1). Because Tibetan foxes are not they did not differ sufficiently among sites with and without known to kill ungulates (Clark et al. 2008), we interpret their Tibetan fox occupancy. The best-supported models suggested presence in diets as indicating scavenging rather than that Tibetan fox occupancy declined from near certainty at high predation. In only 3 of the 36 fox scats containing prey pika abundance, to near 0 at low pika abundance. We interpret species other than plateau pika was the read number of the these relationships as supporting our hypothesis that, in the other prey species more than a minor component (2 scats with absence of plateau pikas, Tibetan foxes in our study area were more Microtus-assigned reads than pika, and 1 scat containing incapable of sustaining themselves. In short, plateau pikas 79 reads of yak versus 129 reads of pika). The 1 scat that was constituted foraging habitat for Tibetan foxes. identified as coming from a wolf (348 reads) contained a faint With the exception of zokors, field exigencies prevented us trace (3 reads) of domestic sheep and of Tibetan fox (1 read). from documenting the presence or quantifying the abundance of alternative prey species for Tibetan foxes (i.e., other rodents, birds, or invertebrates). Thus, one could argue that our design DISCUSSION left open the possibility that other prey species whose presence Within our broadly defined study area, Tibetan fox site was highly correlated with that of plateau pikas were the real, if occupancy was strongly associated with presence and abun- unacknowledged, driver of Tibetan fox occupancy. If so, dance of plateau pikas. No alternative hypotheses to predict the however, we would have expected to see the importance of the presence of Tibetan foxes were supported. The variables alternative prey species reflected in Tibetan fox diets. We elevation, habitat type, level of human disturbance, whether or observed no such signal. In fact, dietary analyses showing

FIG.3.—Probability of site occupancy by Tibetan fox (Vulpes ferrilata) as indexed by presence of scats, as a function of an index of pikas (Ochotona curzoniae) seen and pika burrows counted, Qinghai Province, autumn 2011 (see text). Coefﬁcients used are those from the top-ranking model from Table 1. Shown are estimates of Tibetan fox occupancy when the burrow index is 0 (dotted line), 5 (dashed line), and 10 (solid line).

overwhelming predominance of plateau pikas, both by condition for Tibetan foxes; we caution against interpreting it frequency and relative abundance, corroborated and strength- as a comprehensive analysis of the fox’s ecological niche. ened the proposition that Tibetan foxes depended on pikas as a Our finding that Tibetan foxes appear to be obligate prey species. We note that although our sampling was predators of plateau pikas in our study area has important restricted to autumn and early winter, these dietary results ramifications for conservation policy. The practice of poison- corroborate those of Schaller (1998), obtained in June, and Liu ing pikas ostensibly to ‘‘restore’’ grassland health, even within et al. (2010), obtained during March through May as well as designated nature reserves, continues to be a common practice September and October of 2 separate years. Our examination of on the Qinghai-Tibetan Plateau, despite increasing concerns coarsely mapped geographic distribution of the 2 species among both Chinese and western scientists about its wisdom (Hou and Shi 2002; Zhang et al. 2003a; Smith et al. 2006; further suggested few if any pika-free areas inhabited by Ferreira and Delibes-Mateos 2012). Beyond the Tibetan fox of Tibetan foxes. concern to us here, a number of species have been documented We do not claim that no factors aside from pika presence are as predators of, or strong commensal associates with, pikas important to Tibetan foxes. As a mesocarnivore that can (Smith and Foggin 1999; Lai and Smith 2003; Arthur et al. function as prey as well as predator, the presence and 2008). The rationale most often cited for removing pikas, that characteristics of larger predators no doubt constrains their their burrowing and foraging degrades grassland condition, has realized niche (e.g., Payne et al. 2008). Observations of been seriously questioned (Pech et al. 2007; Delibes-Mateos et radiomarked Tibetan foxes (Liu et al. 2007) suggested that al. 2011). Evidence now suggests that, in most cases, high pika their use of space reflected efforts to avoid detection by wolves density is a consequence rather than a cause of sparse cover and avian predators (e.g., raptors). Thus, our conclusion is that and reduced height of plateau vegetation (Shi 1983; Holzner pika presence constitutes a necessary but not sufficient and Kriechbaum 2001).

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FIG.4.—Approximate geographic distributions of the Tibetan fox (Vulpes ferrilata; dark, solid line [adapted from Schaller et al. 2008]) and plateau pika (Ochotona curzoniae; dash–dot line [Smith and Johnston 2008]), superimposed on the outline map of western China (thin, solid line), and showing the 3,000-m elevation contour (in gray). Both range maps are approximate; that of the Tibetan fox is approximately 90% nested within that of the plateau pika.

At present, Tibetan fox populations appear to remain healthy reduction or elimination (Ma 2006; Smith et al. 2006; Harris within appropriate habitats on the Qinghai-Tibetan Plateau, but 2008), even where conservation of biodiversity is a stated land- this may owe less to the objectives of Chinese policy toward management objective. Our finding that the Tibetan fox plateau pikas than to the ineffectiveness of this policy’s requires pikas for its continued existence provides evidence implementation. Although Botulinin-C, the poison Chinese of an additional unintended consequence of this policy. authorities have most often used in recent years to kill pikas, is highly toxic (Shen 1987), reduction programs have generally ACKNOWLEDGMENTS employed unskilled workers. Required to cover large areas on foot, workers probably fail in their goal to find all pika coteries, Primary funding came from the Chinese Academy of Sciences Senior International Scientist Program awarded to RBH. Supplemental and thus many pikas targeted for killing no doubt survive support was received from the Denver Zoological Society, and simply by the grace of their remote location. Because pikas are additional logistical support from Qinghai Normal University, biologically capable of rapid recovery, densities can rebound to Northwest Institute of Plateau Biology, and Shan Shui. Fieldwork preremoval levels within a few years (Pech et al. 2007; Qu et was ably assisted by Duojieduanzhi. Additional support in the field al. 2013). That said, local agriculture and grazing bureaus was provided by Y. L. Liu, W. Liu, W. Y. Wang, Pera, Duojiejia, and within western China continue to pursue a policy of pika Wanmaben. We thank L. K. Zhang (Kunming Institute of Zoology)

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APPENDIX I Sites surveyed for Tibetan fox (Vulpes ferrilata) occupancy, October–November 2011 (n ¼ 62). Shown are site names (Township); site number within the township (Site number); date sampled (Sampled); mean site elevation (m, n ¼ 8/site; Elevation); human disturbance (low, moderate, high; Disturbance); presence of roads (low, moderate, high; Roads); habitat type (Habitat); presence of water (low, moderate, high; Water); presence of livestock (1 ¼ yes; Livestock present); mean vegetation cover (%, n ¼ 16/site; Veg cover); mean vegetation height (cm, n ¼ 16/site; Veg height); mean number of pika (Ochotona curzoniae) burrows within circular 78.5-m2 plots (n ¼ 16/site; Pika burrows); mean number of zokor (Eospalax fontanierii) mounds within circular plots (n ¼ 16/site; Zokor mounds); number of pikas seen/km transect (Pikas seen/km); and number of collected scats positively identiﬁed as Tibetan fox (see text; Fox scat).

Site Livestock Veg Veg Pika Zokor Pikas Fox Township number Sampled Elevation Disturbance Roads Habitat Water present cover height burrows mounds seen/km scats Dawu 1 7 October 2011 3,965 L H Meadow H 1 54.6 6.4 39.8 0.0 70.0 6 Dawu 2 7 October 2011 3,850 L H Meadow L 0 35.5 10.4 34.5 0.0 10.0 3 Dawu 3 8 October 2011 3,793 L L Meadow L 0 56.9 4.5 28.1 0.0 47.0 1 Dawu 4 8 October 2011 3,793 L L Meadow L 0 44.7 4.7 24.0 0.0 26.0 1 Dawu 5 8 October 2011 3,846 L L Meadow L 0 62.2 4.7 23.9 0.0 4.0 3 Dawu 6 8 October 2011 3,868 L H Steppe L 0 40.3 4.8 24.3 0.0 12.0 5 Dawu 7 8 October 2011 3,758 L M Weedy L 0 77.5 15.9 0.0 0.0 0.0 0 Drinchen 1 24 October 2011 4,171 L L Meadow L 0 46.9 5.5 34.2 0.0 81.5 2 Drinchen 2 24 October 2011 4,195 L L Meadow L 0 49.7 4.8 33.0 0.0 76.0 1 Drinchen 3 24 October 2011 4,193 L L Meadow L 0 55.0 4.8 40.9 0.0 110.0 6 Drinchen 4 24 October 2011 4,269 L L Meadow L 1 49.7 5.0 21.6 0.0 27.5 1 Drinchen 5 24 October 2011 4,245 L M Meadow L 1 53.4 6.3 19.4 0.0 13.0 1 Drinchen 6 25 October 2011 4,249 L L Meadow L 1 60.6 7.2 37.9 0.0 25.5 5 Drinchen 7 29 October 2011 4,223 L L Meadow L 0 55.9 5.3 26.7 0.0 54.5 2 Drinchen 8 29 October 2011 4,196 L L Steppe L 0 52.8 7.8 24.4 0.0 37.5 3 Drinchen 9 29 October 2011 4,198 L L Steppe L 0 43.4 4.8 27.5 0.0 61.0 1 Drinchen 10 29 October 2011 4,195 L L Steppe L 1 56.3 8.1 25.8 0.0 70.5 1 Drinchen 11 29 October 2011 4,204 L L Steppe L 1 51.9 5.7 29.0 0.0 42.5 2 Gonghe 1 1 December 2011 3,776 L L Steppe L 0 82.5 26.3 0.9 0.0 0.0 0 Gouli 1 15 November 2011 4,014 M M Steppe M 0 43.1 8.2 10.8 0.0 26.0 10 Gouli 2 15 November 2011 4,121 L L Steppe L 0 19.4 8.1 18.5 0.0 19.0 8 Gouli 3 15 November 2011 4,087 L L Steppe L 0 14.6 4.7 16.3 0.0 43.5 0 Gouli 4 17 November 2011 3,954 L M Steppe L 1 29.1 8.4 8.8 0.4 24.0 8 Gouli 5 17 November 2011 3,914 L H Steppe L 0 20.9 6.9 14.4 0.2 14.0 1 Gouli 6 17 November 2011 3,994 L L Steppe L 0 24.7 15.3 12.7 0.0 1.5 2 Gouli 7 17 November 2011 3,875 L L Steppe L 0 25.0 4.7 24.8 0.0 16.0 10 Gouli 8 17 November 2011 3,859 L L Steppe L 0 34.7 40.0 0.6 0.0 0.0 0 Guinan 1 6 October 2011 3,477 L M Steppe L 0 74.7 20.3 22.3 2.5 18.8 3 Gyegu 1 20 October 2011 3,845 L L Meadow L 0 45.3 5.0 9.9 0.0 3.0 0 Gyegu 2 20 October 2011 3,957 L L Steppe L 0 87.2 21.3 5.2 0.0 0.0 0 Gyegu 3 20 October 2011 3,975 L L Meadow L 1 61.6 11.6 0.0 0.0 0.0 0 Gyegu 4 20 October 2011 3,996 L L Meadow L 0 59.4 7.2 13.8 0.0 5.0 4 Gyegu 5 20 October 2011 3,921 L M Meadow H 0 57.2 5.3 15.8 0.0 4.0 0 Gyegu 6 20 October 2011 3,935 L L Meadow H 0 59.4 5.0 36.8 0.0 21.0 2 Gyegu 7 20 October 2011 3,970 L L Meadow L 0 73.1 12.8 32.4 0.0 8.0 0 Haibei 1 9 November 2011 3,509 L L Steppe L 0 91.9 31.9 1.8 0.0 0.0 0 Haibei 2 9 November 2011 3,611 L L Meadow L 0 54.1 7.5 37.0 2.4 69.5 4 Haibei Station 1 9 November 2011 3,183 L L Meadow L 1 89.1 23.8 2.4 0.6 0.0 0 Nangchen 1 16 October 2011 4,244 L L Steppe L 0 74.4 5.0 48.6 0.0 15.5 1 Nangchen 2 17 October 2011 4,302 L L Steppe H 0 56.3 3.9 39.9 0.0 38.0 6 Nangchen 3 17 October 2011 4,208 L L Steppe L 1 51.6 4.0 25.5 0.0 47.5 2 Nangchen 4 17 October 2011 3,969 M H Meadow L 1 74.4 20.6 6.1 0.0 17.0 1 Tongde 1 9 October 2011 3,832 L M Steppe L 0 59.1 4.6 33.7 2.2 71.0 3 Zeku 1 6 October 2011 3,387 M M Steppe L 1 48.1 15.3 8.5 0.8 4.8 0 Zhiduo 1 27 November 2011 4,664 L L Meadow L 0 68.4 26.6 1.5 4.0 0.5 0 Zhiduo 2 27 November 2011 4,759 L L Meadow L 0 87.8 27.2 0.3 0.0 0.0 0 Zhiduo 3 27 November 2011 4,740 L L Meadow L 1 80.3 34.8 16.6 0.0 0.0 0

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APPENDIX I Continued.

Site Livestock Veg Veg Pika Zokor Pikas Fox Township number Sampled Elevation Disturbance Roads Habitat Water present cover height burrows mounds seen/km scats Zhiduo 4 27 November 2011 4,705 M L Meadow L 0 43.8 5.6 14.8 0.0 25.0 1 Zhiduo 5 27 November 2011 4,651 L L Weedy L 0 4.8 1.8 8.4 0.0 2.0 0 Zhiduo 6 27 November 2011 4,611 L L Steppe L 0 61.9 5.3 18.9 0.0 7.5 1 Zhiduo 7 28 November 2011 4,548 L L Steppe L 0 24.4 4.5 14.4 0.0 3.0 0 Zhiduo 8 28 November 2011 4,505 L L Steppe L 0 58.8 5.9 18.6 0.0 9.5 0 Zhiduo 9 28 November 2011 4,594 L L Meadow L 0 45.9 5.0 14.9 0.0 80.5 21 Zhiduo 10 28 November 2011 4,592 L L Meadow L 0 51.3 14.4 10.8 0.0 18.5 0 Zhiduo 11 28 November 2011 4,707 L L Meadow L 0 66.9 9.7 0.4 0.0 6.0 0 Zhiduo 12 28 November 2011 4,717 L L Meadow L 1 73.4 22.9 2.1 0.0 8.0 0 Zhiduo 13 28 November 2011 4,682 L M Meadow L 0 51.9 8.8 0.1 0.0 0.0 0 Zhiduo 14 28 November 2011 4,675 L L Meadow L 0 75.0 21.9 6.6 0.0 4.0 0 Zhiduo 15 28 November 2011 4,649 L L Meadow L 0 70.3 16.9 1.5 0.0 1.5 1 Zhiduo 16 28 November 2011 4,659 L M Meadow L 0 41.3 3.9 0.6 0.1 27.5 1 Zhiduo 17 28 November 2011 4,630 L L Meadow L 0 57.8 11.6 21.7 0.0 15.5 0 Zhiduo 18 28 November 2011 4,214 L L Steppe L 0 61.3 5.0 3.9 0.0 12.0 0

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