Dynamics of a low‐density tiger population in Southeast Asia in the context of improved law enforcement

Abstract

Recovering small populations of threatened species is an important global conservation strategy. Monitoring the anticipated recovery, however, often relies on uncertain abundance indices rather than on rigorous demographic estimates. To counter the severe threat from poaching of wild tigers (Panthera tigris), the Government of Thailand established an intensive patrolling system in 2005 to protect and recover its largest source population in Huai Kha Khaeng Wildlife Sanctuary. Concurrently, we assessed the dynamics of this tiger population over the next 8 years with rigorous photographic capture-recapture methods. From 2006 to 2012, we sampled across 624-1026 km(2) with 137-200 camera traps. Cameras deployed for 21,359 trap days yielded photographic records of 90 distinct individuals. We used closed model Bayesian spatial capture-recapture methods to estimate tiger abundances annually. Abundance estimates were integrated with likelihood-based open model analyses to estimate rates of annual and overall rates of survival, recruitment, and changes in abundance. Estimates of demographic parameters fluctuated widely: annual density ranged from 1.25 to 2.01 tigers/100 km(2) , abundance from 35 to 58 tigers, survival from 79.6% to 95.5%, and annual recruitment from 0 to 25 tigers. The number of distinct individuals photographed demonstrates the value of photographic capture-recapture methods for assessments of population dynamics in rare and elusive species that are identifiable from natural markings. Possibly because of poaching pressure, overall tiger densities at Huai Kha Khaeng were 82-90% lower than in ecologically comparable sites in India. However, intensified patrolling after 2006 appeared to reduce poaching and was correlated with marginal improvement in tiger survival and recruitment. Our results suggest that population recovery of low-density tiger populations may be slower than anticipated by current global strategies aimed at doubling the number of wild tigers in a decade.

Impact of prey occupancy and other ecological and anthropogenic factors on tiger distribution in Thailand's western forest complex

“…Evidence indicates these human settlements reduce abundance or led to shifts in distribution of large mammals (Duengkae, Maneerat, Pattanavibool, & Marod, ). Despite establishment of 149 ranger stations in WEFCOM, poaching, illegal logging, and harvesting of non‐timber forest products continue to negatively impact the distribution and abundance of tigers and other large mammals (Duangchantrasiri et al, ).…”

“…Three protected areas, Thung Yai East (TYE), Thung Yai West (TYW), and Huai Kha Khaeng (HKK), which together form a World Heritage Site (6,400 km 2 ), represent the core of WEFCOM. This core area supports the highest density of tigers on the landscape (Duangchantrasiri et al, ; Simcharoen, Pattanavibool, Karanth, Nichols, & Kumar, ) and contains one of only four remaining source populations of tigers worldwide that have, under current management, a high probability of being viable for the next 100 years (Kenney, Allendorf, McDougal, & Smith, ). Elsewhere in Southeast Asia tiger populations are on the verge of extirpation.…”

“…The landscape also supports numerous other threatened wildlife species including the tiger's main prey: gaur ( Bos gaurus ), banteng ( Bos javanicus ), wild water buffalo ( Bubalus arnee ), and sambar ( Rusa unicolor ) (Simcharoen, Simcharoen, Duangchantrasiria, Bump, & Smith, ). Data from camera‐trapping and radio telemetry suggest that HKK alone supports an estimated 35 to 58 tigers (Simcharoen et al, ; Duangchantrasiri et al, ). Female home ranges there vary from 35 to 105 km 2 (Simcharoen, Savini, Gale, Simcharoen, et al, ).…”

Relationships between humans and ungulate prey shape Amur tiger occurrence in a core protected area along the Sino‐Russian border

“…Conservation should also focus on direct threats on tigers such as poaching (Goodrich et al, ). Meanwhile, conservation efforts need to target on human‐induced threat on prey by enhancing dynamic prey population monitor and identifying related anthropogenic influences (Duangchantrasiri et al, ; Kawanishi et al, ).…”

Protected area complexes: a new approach to connectivity in Thailand

“…1), which includes four National Parks and five Wildlife Sanctuaries, covering 4,816.9 km 2 . A 10-year (2013-2022) ecological management plan has been proposed for these latter four, with a focus on corridor management (Emphandhu et al, 2012).…”