Browsing by Author "Parakkasi, Karmila"
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- Population Status of a Cryptic Top Predator: An Island-Wide Assessment of Tigers in Sumatran RainforestsWibisono, Hariyo T.; Linkie, Matthew; Guillera-Arroita, Gurutzeta; Smith, Joseph A.; Sunarto, Sunarto; Pusparini, Wulan; Asriadi; Baroto, Pandu; Brickle, Nick; Dinata, Yoan; Gemita, Elva; Gunaryadi, Donny; Haidir, Iding A.; Herwansyah; Karina, Indri; Kiswayadi, Dedy; Kristiantono, Decki; Kurniawan, Harry; Lahoz-Monfort, Jose J.; Leader-Williams, Nigel; Maddox, Tom; Martyr, Deborah J.; Maryati; Nugroho, Agung; Parakkasi, Karmila; Priatna, Dolly; Ramadiyanta, Eka; Ramono, Widodo S.; Reddy, Goddilla V.; Rood, Ente J. J.; Saputra, Doddy Y.; Sarimudi, Ahmad; Salampessy, Adnun; Septayuda, Eka; Suhartono, Tonny; Sumantri, Ade; Susilo; Tanjung, Iswandri; Tarmizi; Yulianto, Koko; Yunus, Mohammad; Zulfahmi (PLOS, 2011-11-02)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.
- Threatened predator on the equator: multi-point abundance estimates of the tiger Panthera tigris in central SumatraSunarto, Sunarto; Kelly, Marcella J.; Klenzendorf, Sybille; Vaughan, M. R.; Zulfahmi; Hutajulu, M. B.; Parakkasi, Karmila (Cambridge University Press, 2013-04)Information on spatial and temporal variation in abundance is crucial for effective management of wildlife. Yet abundance estimates for the Critically Endangered Sumatran tiger Panthera tigris sumatrae are lacking from Riau, the province historically believed to hold the largest percentage of this subspecies. Recently, this area has had one of the highest global rates of deforestation. Using camera traps we investigated tiger abundance across peatland, flat lowland, and hilly lowland forest types in the province, and over time, in the newly established Tesso Nib National Park, central Sumatra. We estimated densities using spatially explicit capture-recapture, calculated with DENSITY, and traditional capture-recapture models, calculated with CAPTURE. With spatially explicit capture-recapture the lowest tiger density (0.34 +/- SE 0.24 per 100 km(2)) was estimated in the hilly lowland forest of Rimbang Baling and the highest (0.87 +/- SE 0.33 per 100 km(2)) in the flat lowland forest of the Park. Repeated surveys in the Park documented densities of 0.63 +/- SE 0.28 in 2005 to 0.87 +/- SE 0.33 per 100 km(2) in 2008. Compared to traditional capture-recapture the spatially explicit capture-recapture approach resulted in estimates 50% lower. Estimates of tiger density from this study were lower than most previous estimates in other parts of Sumatra. High levels of human activity in the area appear to limit tigers. The results of this study, which covered areas and habitat types not previously surveyed, are important for overall population estimates across the island, provide insight into the response of carnivores to habitat loss, and are relevant to the interventions needed to save the tiger.
- Tigers Need Cover: Multi-Scale Occupancy Study of the Big Cat in Sumatran Forest and Plantation LandscapesSunarto, Sunarto; Kelly, Marcella J.; Parakkasi, Karmila; Klenzendorf, Sybille; Septayuda, Eka; Kurniawan, Harry (PLOS, 2012-01-23)The critically endangered Sumatran tiger (Panthera tigris sumatrae Pocock, 1929) is generally known as a forest-dependent animal. With large-scale conversion of forests into plantations, however, it is crucial for restoration efforts to understand to what extent tigers use modified habitats. We investigated tiger-habitat relationships at 2 spatial scales: occupancy across the landscape and habitat use within the home range. Across major landcover types in central Sumatra, we conducted systematic detection, non-detection sign surveys in 47, 17×17 km grid cells. Within each cell, we surveyed 40, 1-km transects and recorded tiger detections and habitat variables in 100 m segments totaling 1,857 km surveyed. We found that tigers strongly preferred forest and used plantations of acacia and oilpalm, far less than their availability. Tiger probability of occupancy covaried positively and strongly with altitude, positively with forest area, and negatively with distance-to-forest centroids. At the fine scale, probability of habitat use by tigers across landcover types covaried positively and strongly with understory cover and altitude, and negatively and strongly with human settlement. Within forest areas, tigers strongly preferred sites that are farther from water bodies, higher in altitude, farther from edge, and closer to centroid of large forest block; and strongly preferred sites with thicker understory cover, lower level of disturbance, higher altitude, and steeper slope. These results indicate that to thrive, tigers depend on the existence of large contiguous forest blocks, and that with adjustments in plantation management, tigers could use mosaics of plantations (as additional roaming zones), riparian forests (as corridors) and smaller forest patches (as stepping stones), potentially maintaining a metapopulation structure in fragmented landscapes. This study highlights the importance of a multi-spatial scale analysis and provides crucial information relevant to restoring tigers and other wildlife in forest and plantation landscapes through improvement in habitat extent, quality, and connectivity.