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Johansson, O., Samelius, G., Wikberg, E, Chapron, G., Mishra, C., Low, M. (2020). Identification errors in camera- trap studies result in systematic population overestimation. Scientific Reports, 10(6393), 1–10.
Abstract: Reliable assessments of animal abundance are key for successful conservation of endangered species. For elusive animals with individually-unique markings, camera-trap surveys are a benchmark standard for estimating local and global population abundance. Central to the reliability of resulting abundance estimates is the assumption that individuals are accurately identified from photographic captures. To quantify the risk of individual misidentification and its impact on population abundance estimates we performed an experiment under controlled conditions in which 16 captive snow leopards (Panthera uncia) were camera-trapped on 40 occasions and eight observers independently identified individuals and recaptures. Observers misclassified 12.5% of all capture occasions, resulting in systematically inflated population abundance estimates on average by one third (mean ± SD = 35 ± 21%). Our results show that identifying individually-unique individuals from camera-trap photos may not be as reliable as previously believed, implying that elusive and endangered species could be less abundant than current estimates indicate.
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Nawaz, M. A., Khan, B. U., Mahmood, A., Younas, M., Din, J. U, Sutherland, C. (2021). An empirical demonstration of the effect of study design on density estimations. Nature, 11(13104), 1–9.
Abstract: The simultaneous development of technology (e.g. camera traps) and statistical methods, particularly spatially capture–recapture (SCR), has improved monitoring of large mammals in recent years. SCR estimates are known to be sensitive to sampling design, yet existing recommendations about trap spacing and coverage are often not achieved, particularly for sampling wide-ranging and rare species in landscapes that allow for limited accessibility. Consequently, most camera trap studies on large wide-ranging carnivores relies on convenience or judgmental sampling, and often yields compromised results. This study attempts to highlight the importance of carefully considered sampling design for large carnivores that, because of low densities and elusive behavior, are challenging to monitor. As a motivating example, we use two years of snow leopard camera trapping data from the same areas in the high mountains of Pakistan but with vastly different camera configurations, to demonstrate that estimates of density and space use are indeed sensitive to the trapping array. A compact design, one in which cameras were placed much closer together than generally recommended and therefore have lower spatial coverage, resulted in fewer individuals observed, but more recaptures, and estimates of density and space use were inconsistent with expectations for the region. In contrast, a diffuse design, one with larger spacing and spatial coverage and more consistent with general recommendations, detected more individuals, had fewer recaptures, but generated estimates of density and space use that were in line with expectations. Researchers often opt for compact camera configurations while monitoring wide-ranging and rare species, in an attempt to maximize the encounter probabilities. We empirically demonstrate the potential for biases when sampling a small area approximately the size of a single home range—this arises from exposing fewer individuals than deemed sufficient for estimation. The smaller trapping array may also underestimate density by significantly inflating ?. On the other hand, larger trapping array with fewer detectors and poor design induces uncertainties in the estimates. We conclude that existing design recommendations have limited utility on practical grounds for devising feasible sampling designs for large ranging species, and more research on SCR designs is required that allows for integrating biological and habitat traits of large carnivores in sampling framework. We also suggest that caution should be exercised when there is a reliance on convenience sampling.
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Nawaz, M. A., Khan, B. U., Mahmood, A., Younas, M., Din, J. U, Sutherland, C. (2021). An empirical demonstration of the effect of study design on density estimations. Nature, 11(13104), 1–9.
Abstract: The simultaneous development of technology (e.g. camera traps) and statistical methods, particularly spatially capture–recapture (SCR), has improved monitoring of large mammals in recent years. SCR estimates are known to be sensitive to sampling design, yet existing recommendations about trap spacing and coverage are often not achieved, particularly for sampling wide-ranging and rare species in landscapes that allow for limited accessibility. Consequently, most camera trap studies on large wide-ranging carnivores relies on convenience or judgmental sampling, and often yields compromised results. This study attempts to highlight the importance of carefully considered sampling design for large carnivores that, because of low densities and elusive behavior, are challenging to monitor. As a motivating example, we use two years of snow leopard camera trapping data from the same areas in the high mountains of Pakistan but with vastly different camera configurations, to demonstrate that estimates of density and space use are indeed sensitive to the trapping array. A compact design, one in which cameras were placed much closer together than generally recommended and therefore have lower spatial coverage, resulted in fewer individuals observed, but more recaptures, and estimates of density and space use were inconsistent with expectations for the region. In contrast, a diffuse design, one with larger spacing and spatial coverage and more consistent with general recommendations, detected more individuals, had fewer recaptures, but generated estimates of density and space use that were in line with expectations. Researchers often opt for compact camera configurations while monitoring wide-ranging and rare species, in an attempt to maximize the encounter probabilities. We empirically demonstrate the potential for biases when sampling a small area approximately the size of a single home range—this arises from exposing fewer individuals than deemed sufficient for estimation. The smaller trapping array may also underestimate density by significantly inflating
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Atzeni, L., Cushman, S. A., Wang, J., Riordan, P., Shi, K., Bauman, D. (2021). Evidence of spatial genetic structure in a snow leopard population from Gansu, China. Heredity, . Retrieved July 6, 2024, from http://dx.doi.org/https://doi.org/10.1038/s41437-021-00483-0
Abstract: Understanding the spatial structure of genetic diversity provides insights into a populations’ genetic status and enables assessment of its capacity to counteract the effects of genetic drift. Such knowledge is particularly scarce for the snow leopard, a conservation flagship species of Central Asia mountains. Focusing on a snow leopard population in the Qilian mountains of Gansu Province, China, we characterised the spatial genetic patterns by incorporating spatially explicit indices of diversity and multivariate analyses, based on different inertia levels of Principal Component Analysis (PCA). We compared two datasets differing in the number of loci and individuals. We found that genetic patterns were significantly spatially structured and were characterised by a broad geographical division coupled with a fine-scale cline of differentiation. Genetic admixture was detected in two adjoining core areas characterised by higher effective population size and allelic diversity, compared to peripheral localities. The power to detect significant spatial relationships depended primarily on the number of loci, and secondarily on the number of PCA axes. Spatial patterns and indices of diversity highlighted the cryptic structure of snow leopard genetic diversity, likely driven by its ability to disperse over large distances. In combination, the species’ low allelic richness and large dispersal ability result in weak genetic differentiation related to major geographical features and isolation by distance. This study illustrates how cryptic genetic patterns can be investigated and analysed at a fine spatial scale, providing insights into the spatially variable isolation effects of both geographic distance and landscape resistance.
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Pal, R., Sutherland, C., Qureshi, Q., Sathyakumar, S. (2021). Landscape connectivity and population density of snow leopards across a multi-use landscape in Western Himalaya. Animal Conservation, . Retrieved July 6, 2024, from http://dx.doi.org/https://doi.org/10.1111/acv.12754
Abstract: Human modification and habitat fragmentation significantly impact large carnivores requiring large, connected habitats to persist in a landscape. Understanding species responses to such change and the protection of critical areas and connectivity they provide is essential when planning effective conservation strategies. Our study examines the spatial distribution of the snow leopard (Panthera uncia) across a gradient of protection status, anthropogenic pressures and habitat types in the Gangotri landscape (~4600 km2), Western Himalaya. Using spatial capture-recapture modeling, we analyzed a 4-year camera trapping dataset (2015–2019) to assess the relationship between snow leopard movement and topography and identified the conducible areas for facilitating movement across the landscape. Snow leopard density was positively associated with elevation and slope, and was higher in protected areas (summer: 1.42 SE 0.02/100km2; winter 2.15 SE 0.03 vs. summer: 0.4 SE 0.01; winter: 0.6 SE 0.01 for unprotected areas). Precipitous terrain and several prominent mountain peaks were found to be resistant to snow leopard movement. Even with a range of human activities inside protected areas, the higher density suggests a positive impact of protection. Density-weighted connectivity showed that conducible areas are available between the Gangotri landscape and the adjacent protected areas. However, compared to protected area, these areas are relatively less used and require attention for management. We recommend regulating human activities and co-managing pastures with local communities to revive prey base outside protected areas, especially in corridors, to ensure such areas are functionally conducive. Our study provides a framework to collectively quantitate the spatial pattern of abundance, distribution and connectivity. Our approach has broad applicability for policymakers to develop strategic plans for balancing the conservation of species, and other land uses in a multi-use landscape.
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Thapa, K. (2021). An experience of surplus killing of livestock by a snow leopard in Nepal. CATnews, Winter 2021(74), 18–21.
Abstract: Among many other threats, retaliatory killing of snow leopards Panthera uncia by people in retribution of livestock depredation is the foremost challenge for long-term survival of snow leopards. Surplus killing of up to 100 or more goats and sheep by snow leopard in a single night have been reported in snow leopard range’ countries including Nepal. Such incidences are unusual, but their impacts are substantial for subsistence agropastoral communities and snow leopard survival. Direct observation of surplus killing of livestock by a snow leopard in the corral is very rare. Here I report one incidence in a remote part of Nepal where a snow leopard killed 44 goats and was then trapped itself in a corral. This note highlights how I managed to rescue the trapped snow leopard.
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Pandey, B. P., Thami, S., Shrestha, R., Subedi, N., Chalise, M. K., Ale, S. B. (2021). Snow leopards and prey in Rolwaling Valley, Gaurishankar Conservation Area, Nepal. CATnews, 74(Windter 2021), 14–19.
Abstract: The snow leopard Panthera uncia, an apex predator of the Himalayan ecosystem, often shares habitat with the wolf, Canis lupus, red fox Vulpes vulpes, and other carnivores. A biodiversity monitoring programme primarily focused on the assessment of the status of snow leopard and its prey in Rolwaling valley of Gaurishankar Conservation Area, Nepal, was carried out during June–November 2019. We deployed single camera traps in each of twelve grids sized 16 km2 each, operated 24 hours, and left alone for the whole study period. A single snow leopard was captured thrice on same camera in Rhododendron anthopogon-Hippophae thibetana scrubland, near Tsho Rolpa glacial lake (4,536 m). Alongwith snow leopard, wolves were also photographed at three sites namely Yelung pass (4,956 m), Tsho Rolpa (4,536 m) and Dudhkunda ridgeline (5,091 m). The red fox was the most frequent predator in Rolwaling while stone marten Martes foina, yellow-throated marten Martes flabigula, and yellow-belied weasel Mustella katiyah were captured occasionally. Photo capture rate index PCRI per 100 trap nights was calculated for all identifiable species where snow leopard and wolf had PCRI values of 0.35 and 0.71, respectively. The Cumulative PCRI values suggest a pyramid shaped community structure in Rolwaling with small herbivores (including game birds) with broad base (PCRI 22.29) followed by large herbivores (10.38) and small-medium sized carnivores (6.96). The top predators (snow leopard and wolf) produces 1.06 photographic rate index. The declaration of Gaurishankar conservation area and continuous efforts from conservation area management committees, strict cultural rules from local Buddhist community in the valley are found possibly favoured the recolonization of the wolf and frequent visits by snow leopard.
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Smith, H. F., Townsend, K. E. B., Adrian, B., Levy, S., Marsh, S., Hassur, R., Manfredi, K., Echols, M. S. (2021). Functional Adaptations in the Forelimb of the Snow Leopard (Panthera uncia). Integrative and Comparative Biology, 61(5), 1852–1866.
Abstract: The snow leopard (Panthera uncia) is anatomically and physiologically adapted for life in the rocky terrain of alpine zones in Central and South Asia. Panthera uncia is scansorial, and typically hunts solitarily by using overhead ambush of prey, rather than the typical stalking pattern of other large pantherines. In this study, we conducted dissections, detailed documentation, and illustrated the forelimb anatomy of two adult P. uncia specimens (1M/1F). Qualitative and quantitative data revealed an intriguing combination of functional adaptations illustrating a balance between the diverse demands of head-first descent, pouncing, climbing across rocky terrain, restraint of large prey, rapid pursuit, and navigating deep snow. In many forelimb proportions, P. uncia is intermediate between the cursorial Acinonyx jubatus (cheetah) and the scansorial forest dwelling Panthera onca (jaguar). Enlarged scapular and pectoral musculature provide stability to the shoulder girdle during grappling with large prey, as well as support during jumping and climbing. A small, unarticulated bony clavicle may provide greater stability to the forelimb, while still allowing flexibility. In the brachium and antebrachium of P. uncia, there is a functional compromise between the powerful grip needed for grasping large prey and the stability necessary for rapid pursuit of prey over uneven, rocky terrain. A unique bifurcation in the tendon of m. biceps brachii may provide additional functional stability at the radiohumeral joint. Intrinsic muscles of the palmar manus are broad and fleshy, acting as an enlarged surface area to evenly distribute body weight while walking on soft snow. However, muscles that act to provide fine manual manipulation are reduced, as in other large prey specialists. Overall, P. uncia displays morphological adaptive parallels with scansorial, large prey spe- cializing pantherines, such as P. onca, while also showing adaptations for running.
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Shao, X., Lu, Q., Xiong, M., Bu, H., Shi, X., Wang, D., Zhao, J., Li, S., Yao, M. (2021). Prey partitioning and livestock consumption in the world’s richest large carnivore assemblage. Current Biology, 31, 4887–4897.
Abstract: Large mammalian carnivores have undergone catastrophic declines during the Anthropocene across the world. Despite their pivotal roles as apex predators in food webs and ecosystem dynamics, few detailed di- etary datasets of large carnivores exist, prohibiting deep understanding of their coexistence and persistence in human-dominated landscapes. Here, we present fine-scaled, quantitative trophic interactions among sym- patric carnivores from three assemblages in the Mountains of Southwest China, a global biodiversity hotspot harboring the world’s richest large-carnivore diversity, derived from DNA metabarcoding of 1,097 fecal sam- ples. These assemblages comprise a large-carnivore guild ranging from zero to five species along with two mesocarnivore species. We constructed predator-prey food webs for each assemblage and identified 95 vertebrate prey taxa and 260 feeding interactions in sum. Each carnivore species consumed 6–39 prey taxa, and dietary diversity decreased with increased carnivore body mass across guilds. Dietary partitioning was more evident between large-carnivore and mesocarnivore guilds, yet different large carnivores showed divergent proportional utilization of different-sized prey correlating with their own body masses. Large car- nivores particularly selected livestock in Tibetan-dominated regions, where the indigenous people show high tolerance toward wild predators. Our results suggest that dietary niche partitioning and livestock subsidies facilitate large-carnivore sympatry and persistence and have key implications for sustainable conservation promoting human-carnivore coexistence.
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Locke-Jones, J. (2022). Wildlife Conservation in the Digital Age. https://impact.wp.st-andrews.ac.uk/wildlife-conservation-in-the-digital-age/.
Abstract: Our understanding of the state of the world’s wildlife is dependent upon data. Without an accurate survey of species populations, our efforts to improve their chances of survival and to limit our impact on their wellbeing will always be limited. Unfortunately, many endangered species live in areas inhospitable to us – and in any case, a human-led survey can only continue for so long before the surveyors need to rest.
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