Disease cross-transmission between wild and domestic ungulates can negatively impact livelihoods and wildlife conservation. In Pin valley, migratory sheep and goats share pastures seasonally with the resident Asiatic ibex (Capra sibirica), leading to potential disease cross-transmission. Focussing on gastro-intestinal nematodes (GINs) as determinants of health in ungulates, we hypothesized that infection on pastures would increase over summer from contamination by migrating livestock. Consequently, interventions in livestock that are well-timed should reduce infection pressure for ibex. Using a parasite life-cycle model, that predicts infective larval availability, we investigated GIN transmission dynamics and evaluated potential interventions. Migratory livestock were predicted to contribute most infective larvae onto shared pastures due to higher density and parasite levels, driving infections in both livestock and ibex. The model predicted a c.30-day anti-parasitic intervention towards the end of the livestock’s time in Pin would be most effective at reducing GINs in both hosts. Albeit with the caveats of not being able to provide evidence of interspecific parasite transmission due to the inability to identify parasite species, this case demonstrates the usefulness of our predictive model for investigating parasite transmission in landscapes where domestic and wild ungulates share pastures. Additionally, it suggests management options for further investigation.

Conservation policy for the high mountains of Asia increasingly recognises the need to encompass large multi-use landscapes beyond the protected area network. Due to limited long-term research in this region, our understanding of even fundamental processes, such as factors regulating large mammal populations is poor. Understanding the factors that regulate animal populations, especially those generating cyclicity, is a long-standing problem in ecology. Long-term research across multiple taxa (mainly from Europe and North America) has focussed on the relative roles of food and predation in generating cyclicity in population dynamics. It remains unclear how trophic interactions that are influenced by anthropogenic stressors can affect population dynamics in human-modified landscapes. We present a 10-year study to compare the effects of livestock grazing on density-dependent dynamics in two populations of bharal, Pseudois nayaur, in the Himalayas. We combine this with a mechanistic understanding of whether density dependence in these two sites acts predominantly by affecting adult survival or recruitment. We compared and quantified density dependence in the bharal population by fitting Bayesian Gompertz state-space models. We found evidence for negative density dependence which indicates possible cyclic dynamics in the bharal population of the site (Tabo) with low livestock density. The population dynamics of this site were driven by recruited offspring-with a 2-year density-dependent lag effect-rather than adult survival. In the site with high livestock density (Kibber), this density dependence was not detected. We postulate the potential role of excessive grazing by livestock in affecting offspring recruitment, thereby affecting the bharal population in Kibber. Synthesis and applications: Our results suggest that conservation action to facilitate wild herbivore population recovery, such as the development of protected areas and village reserves, needs to account for density-dependent regulation. Sites with trophy hunting require continuous monitoring to understand the effects of density dependence so that appropriate hunting quotas can be formulated. Our results suggest that conservation action to facilitate wild herbivore population recovery, such as the development of protected areas and village reserves, needs to account for density-dependent regulation. Sites with trophy hunting require continuous monitoring to understand the effects of density dependence so that appropriate hunting quotas can be formulated.image

AbstractEffective management of charismatic large carnivores requires robust monitoring of their population at local, regional and global scales. While enormous progress has been made to estimate carnivore populations at local scales, estimates at regional and global scales remain elusive. In the first systematic effort at a large regional scale, we estimated the population of the elusive snow leopardPanthera unciaover an area of 26,112 km2in the Indian state of Himachal Pradesh.We stratified the entire snow leopard habitat in Himachal Pradesh based on an occupancy survey. Subsequently, we conducted camera trapping surveys at 10 sites distributed proportionately, that is with similar coverage probability across the three strata. We conducted simulations to understand how unidentified captures could affect our model estimate. We also assessed populations of the primary wild ungulate prey of snow leopards – blue sheepPseudois nayaurand Siberian ibexCapra sibirica.Our results yielded a mean estimated density of 0.19 (95% confidence interval [CI]: 0.12–0.31) snow leopards per 100 km2and population size of 51 (95% CI: 34–73) snow leopards in Himachal Pradesh. The density estimates for individual sites ranged from 0.08 to 0.37 snow leopards per 100 km2. Simulations showed that unidentified snow leopard captures did not seem to affect the accuracy of our model estimate but could have affected the precision. Wild ungulate prey density ranged from 0.11 to 1.09 per km2. Snow leopard density showed a positive linear relationship with prey density (slope = 0.25,SE = 0.08,P = 0.01,R2 = 0.51).Our study shows the earlier opinion‐based estimate for Himachal Pradesh to have been significantly positively biased. Using occupancy surveys to stratify large areas in order to design camera trap surveys addresses one of the common spatial sampling biases, that is limited sampling of only prime snow leopard habitats. Our work validates two‐step approach recommended in the ongoing initiative of the 12 snow leopard range countries for Population Assessment of World's Snow leopards (PAWS program), and cautions against the use of opinion‐based estimates for assessing the status of species of critical conservation importance.

Ungulate conservation directly affects conservation of their predators and habitats. Assessing conservation status of ungulates found in the mountains is particularly challenging given the tough terrain and extreme weather. This is true for Central and South Asia’s mountains which harbour high ungulate diversity. Urial Ovis vignei, a Vulnerable wild sheep, occurs patchily across Asian mountains. Ladakh urial Ovis vignei vignei is a subspecies restricted to Ladakh and Gilgit-Baltistan in the trans-Himalaya. Poor understanding of its conservation status has limited conservation efforts in the region. We conducted a distribution survey using single-season single-species occupancy, with spatial replicates accounting for auto-correlated replicate-level presence across the entire potential urial habitat (3425km2) in Ladakh, India. We then identified remaining populations and conducted double-observer surveys to estimate densities. We found urial to use only 32% (16–53%) of its presumed range. We estimated densities of 1.27 (1.27–1.39) urial km−2 and 0.96 (0.96–1.10) urial km−2 across the two landscapes covering 18% of surveyed area. These two areas are currently the last remaining strongholds for the species in India, yet densities were lower than expected when compared to previous studies. Urial distribution in India overlaps with human use like habitations, livestock grazing, and roads, hence effective conservation of the species will need involvement of local communities. We propose annual monitoring of urial and setting up community-based livestock-free reserves across the two landscapes. More such robust investigations at meaningful large scales are needed to direct conservation action for the understudied mountain ungulates of high Asia.

The complexities of multi-use landscapes require sophisticated approaches to addressing disease transmission risks. We explored gastro-intestinal nematode (GINs) infections in the North India Trans-Himalayas through a socio-ecological lens, integrating parasite transmission modelling with field surveys and local knowledge, and evaluated the likely effectiveness of potential interventions. Bharal (blue sheep; Pseudois nayaur), a native wild herbivore, and livestock share pasture year-round and livestock commonly show signs of GINs infection. While both wild and domestic ungulates had GINs infections, egg counts indicated significantly higher parasite burdens in bharal than livestock. However, due to higher livestock densities, they contributed more to the total count of eggs and infective larvae on pasture. Herders also reported health issues in their sheep and goats consistent with parasite infections. Model simulations suggested that pasture infectivity in this system is governed by historical pasture use and gradually accumulated larval development during the summer, with no distinct short-term flashpoints for transmission. The most effective intervention was consequently predicted to be early-season parasite suppression in livestock using temperature in spring as a cue. A 1-month pause in egg output from livestock could lead to a reduction in total annual availability of infective larvae on pasture of 76%, potentially benefitting the health of both livestock and bharal. Modelling suggested that climate change over the past 33 years has led to no overall change in GINs transmission potential, but an increase in the relative influence of temperature over precipitation in driving pasture infectivity. Our study provides a transferable multi-pronged approach to investigating disease transmission, in order to support herders' livelihoods and conserve wild ungulates.