Status and trend of Great Indian Bustard, associated wildlife and threats in Thar

Abstract

Arid ecosystems of India support unique biodiversity and traditional agro-pastoral livelihoods. However, these habitats are highly threatened due to large-scale land-use changes and historical neglect of conservation policies. The Critically Endangered great Indian bustard acts as a flagship and indicator of this ecosystem, for which Government is planning conservation actions that will also benefit associated wildlife. Persistence of this species critically depends on Thar landscape, where ~75 % of the global population resides. Since 2014, Wildlife Institute of India and Rajasthan Forest Department have been jointly conducting scientific surveys to better understand the current status, distribution patterns, and local contexts of key conservation-dependent species in Thar for informing management actions. This study assessed the status of great Indian bustard, chinkara and fox alongside their habitat and anthropogenic pressures across 19,728 km2 of potential bustard landscape in Thar spanning Jaisalmer, Jodhpur and Bikaner districts of Rajasthan. Systematic surveys were conducted in 144 km2 cells from slow-moving vehicle along 17.9 + 3.9SD km transects to record species’ detections, habitat characteristics in sampling plots, and secondary information on species’ occurrences. Multiple teams comprising field biologists and Forest Department staff simultaneously and rapidly sampled 108 cells along 1697 km transects in March 2014, 77 cells along 1246 km transects in March 2015,and 120 cells along 2273 km transects in March 2016. Sampling was carried out in two phases: extensive surveys to assess great Indian bustard occurrence across the landscape and intensive surveys to estimate their density in used cells. Great Indian bustard and other key species' detection data were analyzed in Occupancy and Distance Sampling framework to estimate proportion of sites used and density/abundance. Detection/non-detection data from multiple year surveys (2014-16) showed that great Indian bustard used 10.9 ± 3.4SE % sites (naive occupancy 8.4%). Bird density in used sites (cells where at least one bird was detected during 2015-16) was estimated at 6.5 ± 1.4SE /100 km2. Random sampling of the potential bustard landscape in Thar using line transect distance sampling yielded density and abundance estimates of 0.84 + 0.38 birds/100 km2 and 166 + 74 birds in 2016. During the surveys 38 (2014), 40 (2015) and 37 (2016) individual birds were detected. Bustard-habitat relationships, assessed using 5 multinomial logistic regression, showed that disturbances and level of protection influenced distribution in this landscape. Great Indian bustard occurrence in the landscape declined with distance from enclosure (regression effect size = -0.06 ± 0.02SE), human presence (-3.22 ± 1.52SE) and infrastructural intensity (-3.97 ± 1.61SE). Chinkara was found in 78% sites and its density at landscape-scale was estimated at 187.5 ± 25.1SE animals/100 km2, yielding abundance of 37,000 + 4970SE in 19,728 km2 area (2016). Desert and Indian fox used 60 ± 7SE % of sites, at densities of 14.35 ± 3.46SE desert fox/100km2 and 2.28 ± 1.19SE Indian fox/100km2 at landscape-scale, and abundances of 2830 ± 683SE desert fox and 450 ± 235SE Indian fox in 19,728 km2 area. Eleven percent of sampled cells were found to be of high conservation value, out of which, 62% cells were outside Protected Area. Although some of these 'unprotected' areas benefit from community protection or inviolate spaces created due to Army occupation, others continue to be threatened by hunting and unplanned land-uses. Our study provides robust abundance estimates of key species in Thar. It provides spatially explicit information on species’ distribution and ecological parameters to guide site-specific management and policy. Our questionnaires generated spatial patterns of community composition, livelihoods, livestock holdings and species’ occurrence reports that will help in designing community outreach and conservation programs. Thar supports the largest global population of great Indian bustard and offers the best hope for its persistence. This survey captured snapshots of great Indian bustard distribution that needs to be augmented with satellite telemetry based information on seasonal landscape use to mitigate threats. Based on results and field experiences, we strongly recommend: a) improving great Indian bustard recruitment in existing enclosures using predator-proof-fences and nest-predator removal, b) creating more enclosures or conservation/community reserves in priority conservation cells, c) smart and intensive patrolling to control poaching and generate management information, d) targeted research to understand local ecology of great Indian bustard, characterize threats, and ranging patterns, e) addressing local livelihood concerns through social research, and f) engaging local communities to monitor and protect wildlife through outreach and incentive programs.