Title
Dynamics of a low-density tiger population in Southeast Asia in the context of improved law enforcement
Author(s)
Duangchantrasiri, S.;Umponjan, M.;Simcharoen, S.;Pattanavibool, A.;Chaiwattana, S.;Maneerat, S.;Kumar, N.S.;Jathanna, D.;Srivathsa, A.;Karanth, K.U.
Published
2016
Publisher
Conservation Biology
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 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 eight years, employing rigorous photographic capture-recapture methods. Between 2006–2012, we sampled 624–1026 km2 area deploying 137–200 camera traps, investing 21,359 trap-days effort to photograph 90 distinct individuals. Tiger abundance was estimated each year using closed model Bayesian spatial capture-recapture analyses. 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, with densities ranging between 1.25–2.01 tigers/100 km2, abundances between 35–58 tigers, survival between 79.6%–95.5% and annual recruitment varying between 0–25 tigers. We demonstrate 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, tiger densities at Huai Kha Khaeng were 82–90% lower than in ecologically comparable sites in India. However, intensified patrolling effort after 2006 appeared to reduce poaching, correlated with marginal improvement in tiger survival and recruitment. Our study suggests that population recoveries of low-density tiger populations may be slower than anticipated by current global strategies hoping to ‘double’ wild tiger numbers in a decade. This article is protected by copyright. All rights reserved
Keywords
abundance estimation;camera traps;carnivores;population dynamics;patrolling;over-hunting;spatial capture-recapture models
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