Examining Temporal Sample Scale and Model Choice with Spatial Capture-Recapture Models in the Common Leopard Panthera pardus

Many large carnivores occupy a wide geographic distribution, and face threats from habitat loss and fragmentation, poaching, prey depletion, and human wildlife-conflicts. Conservation requires robust techniques for estimating population densities and trends, but the elusive nature and low densities of many large carnivores make them difficult to detect. Spatial capture-recapture (SCR) models provide a means for handling imperfect detectability, while linking population estimates to individual movement patterns to provide more accurate estimates than standard approaches. Within this framework, we investigate the effect of different sample interval lengths on density estimates, using simulations and a common leopard (Panthera pardus) model system. We apply Bayesian SCR methods to 89 simulated datasets and camera-trapping data from 22 leopards captured 82 times during winter 2010–2011 in Royal Manas National Park, Bhutan. We show that sample interval length from daily, weekly, monthly or quarterly periods did not appreciably affect median abundance or density, but did influence precision. We observed the largest gains in precision when moving from quarterly to shorter intervals. We therefore recommend daily sampling intervals for monitoring rare or elusive species where practicable, but note that monthly or quarterly sample periods can have similar informative value. We further develop a novel application of Bayes factors to select models where multiple ecological factors are integrated into density estimation. Our simulations demonstrate that these methods can help identify the “true” explanatory mechanisms underlying the data. Using this method, we found strong evidence for sex-specific movement distributions in leopards, suggesting that sexual patterns of space-use influence density. This model estimated a density of 10.0 leopards/100 km² (95% credibility interval: 6.25–15.93), comparable to contemporary estimates in Asia. These SCR methods provide a guide to monitor and observe the effect of management interventions on leopards and other species of conservation interest.     

Steps towards sustainable harvest of Ophiocordyceps sinensis in Bhutan

The insect-pathogenic fungus Ophiocordyceps sinensis (better known as Cordyceps sinensis) is harvested over much of the Himalayan plateau as a highly prized remedy in traditional Oriental medicine. Over the past 10 years its financial value has increased dramatically, with collectors paid as much as US $12,500 kg⁻¹ for top-quality material. This is causing significant distortion to local economies, and there is widespread concern that the current rate of collection is unsustainable. This paper introduces the fungus and its insect hosts, documents some of the biological and social constraints to achieving sustainability, describes the socioeconomic climate within which harvest and sale occurs in Bhutan, and details the measures put in place by the Royal Government of Bhutan to promote wise management of this valuable natural resource.

Understanding primate‐human interaction: Socioeconomic correlates of local awareness and attitude toward the endangered golden langur Trachypithecus geei (Khajuria, 1956) in Bhutan

Despite the golden langur's (Trachypithecus geei) endangered and totally protected status, local awareness and attitude toward this species is poorly understood. We investigated local awareness and attitude in Bhutan by interviewing 1,143 households in the districts of Dagana, Sarpang, Trongsa, Tsirang, and Zhemgang, and analyzing data through a conditional inference tree analysis. Most respondents were not aware of the golden langur's nationally protected (53%; n = 604) and globally endangered status (64%; n = 730), but their location of residence (inside/outside a protected area; p < .001) and education level (p < .001) significantly influenced awareness. The majority of respondents (87%; n = 999) liked the golden langur but the attitude was significantly influenced primarily by whether or not they experienced crop damage by golden langurs (p < .001), and subsequently by location of residence (p < .001), local belief (p < .01), gender (p < .05), and personal encounter with a golden langur (p < .001). Socioeconomic variables like age, education level, and annual income did not influence attitude. We recommend environmental education and awareness campaigns outside protected areas, and intensifying existing programs inside protected areas to forge harmonious human‐golden langur coexistence.     

Partial Altitudinal Migration of a Himalayan Forest Pheasant

Background

Altitudinal migration systems are poorly understood. Recent advances in animal telemetry which enables tracking of migrants across their annual cycles will help illustrate unknown migration patterns and test existing hypotheses. Using telemetry, we show the existence of a complex partial altitudinal migration system in the Himalayas and discuss our findings to help better understand partial and altitudinal migration.

Methodology/Principal Findings

We used GPS/accelerometer tags to monitor the migration of Satyr tragopan (Tragopan satyra) in the Bhutan Himalayas. We tagged 38 birds from 2009 – 2011 and found that tragopans are partially migratory. Fall migration lasted from the 3^rd week of September till the 3^rd week of November with migrants traveling distances ranging from 1.25 km to 13.5 km over 1 to 32 days. Snowfall did not influence the onset of migration. Return migration started by the 1^st week of March and lasted until the 1^st week of April. Individuals returned within 4 to 10 days and displayed site fidelity. One bird switched from being a migrant to a non-migrant. Tragopans displayed three main migration patterns: 1) crossing multiple mountains; 2) descending/ascending longitudinally; 3) moving higher up in winter and lower down in summer. More females migrated than males; but, within males, body size was not a factor for predicting migrants.

Conclusions/Significance

Our observations of migrants traversing over multiple mountain ridges and even of others climbing to higher elevations is novel. We support the need for existing hypotheses to consider how best to explain inter- as well as intra-sexual differences. Most importantly, having shown that the patterns of an altitudinal migration system are complex and not a simple up and down slope movement, we hope our findings will influence the way altitudinal migrations are perceived and thereby contribute to a better understanding of how species may respond to climate change.     

Tree shelters facilitate brown oak seedling survival and establishment in a grazing‐dominant forest of Bhutan,Eastern Himalaya

Brown oak (Quercus semecarpifolia) forest is essential for ecological and socioeconomic functions, mainly grazing in the Himalayas. The tree has failed to regenerate naturally and is a threatened species. Restoration of brown oaks is crucial to ensure sustainability while maintaining livestock grazing in these habitats. Achieving this requires cost‐effective restoration techniques that are practicable and sympathetic to the multiple uses of the forest. We assessed the combined effect of grazing (control) and three tree shelters (Protex tubes, mesh wires, and wooden frames) on the field performance of oak seedlings in a forest with heavy grazing pressure. Seedling survival and morphological indicators, including seedling height, collar diameter, sturdiness quotient (SQ), and leaf mass per area (LMA) indices, were measured. More than 90% of control seedlings without protective shelters suffered severe browsing and demonstrated significantly lower survival rates compared to tree shelter seedlings, indicating that grazing was the primary factor governing regeneration success. Seedling survival in tree shelters was three times higher, while the height increase was two times higher than the control. Additionally, locally made mesh wire and wooden tree shelters were more effective than Protex and control in producing quality seedlings reflected by the SQ and LMA values. We suggest that tree shelter is a promising option to restore brown oaks due to its efficacy to defend grazing and support the local community's rights to forest grazing. Our finding is expected to support Bhutan's forest policy of incorporating grazing and tree regeneration into forest management.