7 research outputs found
Population Status of a Cryptic Top Predator: An Island-Wide Assessment of Tigers in Sumatran Rainforests
Large carnivores living in tropical rainforests are under immense pressure from the rapid conversion of their habitat. In response, millions of dollars are spent on conserving these species. However, the cost-effectiveness of such investments is poorly understood and this is largely because the requisite population estimates are difficult to achieve at appropriate spatial scales for these secretive species. Here, we apply a robust detection/non-detection sampling technique to produce the first reliable population metric (occupancy) for a critically endangered large carnivore; the Sumatran tiger (Panthera tigris sumatrae). From 2007â2009, seven landscapes were surveyed through 13,511 km of transects in 394 grid cells (17Ă17 km). Tiger sign was detected in 206 cells, producing a naive estimate of 0.52. However, after controlling for an unequal detection probability (where pâ=â0.13±0.017; ±S.E.), the estimated tiger occupancy was 0.72±0.048. Whilst the Sumatra-wide survey results gives cause for optimism, a significant negative correlation between occupancy and recent deforestation was found. For example, the Northern Riau landscape had an average deforestation rate of 9.8%/yr and by far the lowest occupancy (0.33±0.055). Our results highlight the key tiger areas in need of protection and have led to one area (Leuser-Ulu Masen) being upgraded as a âglobal priorityâ for wild tiger conservation. However, Sumatra has one of the highest global deforestation rates and the two largest tiger landscapes identified in this study will become highly fragmented if their respective proposed roads networks are approved. Thus, it is vital that the Indonesian government tackles these threats, e.g. through improved land-use planning, if it is to succeed in meeting its ambitious National Tiger Recovery Plan targets of doubling the number of Sumatran tigers by 2022
Economics of conservation law enforcement by rangers across Asia
Abstract Biodiversity targets, under the KunmingâMontreal Global Biodiversity Framework, prioritize both conservation area and their effectiveness. The effective management of protected areas (PAs) depends greatly on law enforcement resources, which is often tasked to rangers. We addressed economic aspects of law enforcement by rangers working in terrestrial landscapes across Asia. Accordingly, we used ranger numbers and payment rates to derive continentalâscale estimates. Ranger density has decreased by 2.4âfold since the 1990s, increasing the median from 10.9 to 26.4 km2 of PAs per ranger. Rangers were generally paid more than the minimum wage (median ratio = 1.9) and the typical salaries in agriculture, forestry, and fishing sector (median ratio = 1.2). Annual spending on ranger salaries varied widely among countries, with a median of annual US71 kmâ2 of PA. Nearly 208,000 rangers patrolling Asian PAs provide an invaluable opportunity to develop rangerâbased monitoring plans for evaluating the conservation performance. As decisionâmakers frequently seek an optimum number of law enforcement staff, our study provides a continental baseline median of 46.3 km2 PA per ranger. Our findings also provide a baseline for countries to improve their rangerâbased law enforcement which is critical for their KunmingâMontreal Global Biodiversity Framework targets
Multi-scale habitat selection modeling identifies threats and conservation opportunities for the Sunda clouded leopard (Neofelis diardi)
Summary of Sumatra-wide field survey effort for each landscape.
<p>*Iâ=âglobal priority; IIâ=âregional priority; IIIâ=âlong-term priority.</p>1<p>Kerinci Seblat National Park and Batang Hari Protection Forest and their surrounding forests.</p>2<p>Bukit Barisan Selatan National Park and Bukit Balai Rejang Selatan.</p>3<p>Pasir Pangaraian, Giam Siak, Duri, Balaraja, Tapung.</p>4<p>Tesso Nilo, Bukit Bungkuk, Bukit Rimbang-Baling, Bukit Batabuh, Bukit Tigapuluh, Kerumutan.</p>5<p>Dangku, Bukit Duabelas, Berbak.</p
Sumatran tiger site occupancy () and density () estimates for the best model, averaged for each study area.
<p>The two right-most columns show the estimates conditional to the data observed. Standard errors are shown in brackets.</p
Estimated Sumatran tiger site occupancy and sites with actual indirect tiger sign detections (black dots).
<p>Estimated Sumatran tiger site occupancy and sites with actual indirect tiger sign detections (black dots).</p