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2.
PLoS One ; 13(6): e0198369, 2018.
Article in English | MEDLINE | ID: mdl-29949588

ABSTRACT

With the extirpation of tigers from the Indonesian island of Java in the 1980s, the endemic and Critically Endangered Javan leopard is the island's last remaining large carnivore. Yet despite this, it has received little conservation attention and its population status and distribution remains poorly known. Using Maxent modeling, we predicted the locations of suitable leopard landscapes throughout the island of Java based on 228 verified Javan leopard samples and as a function of seven environmental variables. The identified landscapes covered over 1 million hectares, representing less than 9% of the island. Direct evidence of Javan leopard was confirmed from 22 of the 29 identified landscapes and included all national parks, which our analysis revealed as the single most important land type. Our study also emphasized the importance of maintaining connectivity between protected areas and human-modified landscapes because adjacent production forests and secondary forests were found to provide vital extensions for several Javan leopard subpopulations. Our predictive map greatly improves those previously produced by the Government of Indonesia's Javan Leopard Action Plan and the IUCN global leopard distribution assessment. It shares only a 32% overlap with the IUCN range predictions, adds six new priority landscapes, all with confirmed presence of Javan leopard, and reveals an island-wide leopard population that occurs in several highly fragmented landscapes, which are far more isolated than previously thought. Our study provides reliable information on where conservation efforts must be prioritized both inside and outside of the protected area network to safeguard Java's last remaining large carnivore.


Subject(s)
Conservation of Natural Resources/methods , Endangered Species , Panthera , Animals , Ecosystem , Indonesia , Models, Theoretical , Parks, Recreational , Population Dynamics
3.
PLoS One ; 6(11): e25931, 2011.
Article in English | MEDLINE | ID: mdl-22087218

ABSTRACT

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 2007-2009, seven landscapes were surveyed through 13,511 km of transects in 394 grid cells (17×17 km). Tiger sign was detected in 206 cells, producing a naive estimate of 0.52. However, after controlling for an unequal detection probability (where p = 0.13±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 'global priority' 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.


Subject(s)
Ecosystem , Endangered Species/trends , Food Chain , Tigers , Animals , Conservation of Natural Resources , Geography , Indonesia , Population , Trees
4.
Integr Zool ; 5(4): 313-323, 2010 Dec.
Article in English | MEDLINE | ID: mdl-21392349

ABSTRACT

The majority of wild Sumatran tigers are believed to live in 12 Tiger Conservation Landscapes covering approximately 88,000 km(2) . However, the actual distribution of tigers across Sumatra has never been accurately mapped. Over the past 20 years, conservation efforts focused on the Sumatran tigers have increased, but the population continues to decline as a result of several key threats. To identify the status of the Sumatran tiger distribution across the island, an island-wide questionnaire survey comprised of 35 respondents from various backgrounds was conducted between May and June 2010. The survey found that Sumatran tigers are positively present in 27 habitat patches larger than 250 km(2) and possibly present in another 2. In addition, a review on major published studies on the Sumatran tiger was conducted to identify the current conservation status of the Sumatran tiger. Collectively, these studies have identified several key factors that have contributed to the decline of Sumatran tiger populations, including: forest habitat fragmentation and loss, direct killing of tigers and their prey, and the retaliatory killing of tigers due to conflict with villagers. The present paper provides management authorities and the international community with a recent assessment and a base map of the actual distribution of Sumatran tigers as well as a general overview on the current status and possible future conservation challenges of Sumatran tiger management.


Subject(s)
Conservation of Natural Resources/methods , Tigers/classification , Animals , Ecosystem , Endangered Species , Indonesia
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