Books by Sunarto Sunarto
Tigers (Panthera tigris Linnaeus, 1758) are in danger of extinction. Their populations have decli... more Tigers (Panthera tigris Linnaeus, 1758) are in danger of extinction. Their populations have declined from ~100,000 to only ~3,000 individuals in a century and their habitat has shrunk to less than 7% of the historic range. Of the five extant tiger subspecies, the Sumatran tiger (Panthera tigris sumatrae Pocock, 1929) is the most seriously threatened. Currently determined as Critically Endangered under IUCN criteria, the Sumatran tiger is likely to become extinct unless effective conservation measures are enacted. Threats to the tiger include habitat destruction, killing due to conflict with humans and livestock, and poaching for illegal wildlife trade.
Long-term survival of Sumatran tigers depends largely on the effectiveness of current conservation efforts in every tiger landscape. Successful conservation and management require accurate information on ecology of the species upon which decisions can be based. This study investigated basic ecological aspects of tigers and developed strategies for management and restoration to improve tiger viability in the Central Sumatra landscape. This landscape is comprised of natural forests and plantations managed for timber and agricultural commodities.
The first chapter assesses the variation in tiger abundance across forest types in Southern Riau, and over time in Tesso Nilo National Park, all in Central Sumatra. Using camera traps, my team and I systematically sampled five blocks representing three major forest types in the region: peat land, flat lowland, and hilly lowland. I found that tiger abundance varied by forest type and through time. Excluding two sampling blocks where no tigers were photographed, the lowest tiger density was in peat land forest of Kerumutan, and the highest density was in the flat lowland forest of Tesso Nilo. Repeated sampling in the newly established Tesso Nilo National Park documented a trend of increasing tiger density (SE) from 0.90 (0.38) individuals/100 km2 in 2005 to 1.70 (0.66) individuals/100 km2 in 2008. Overall, tiger densities from this study were lower than most previous estimates from other parts of Sumatra. The trend of increasing tiger density in Tesso Nilo, however, suggests that the tiger population could be augmented by protection of habitats that were previously logged and severely disturbed.
The second chapter examines the occupancy and habitat-use of the tiger across the major landcover types (natural forest, acacia plantation, oilpalm plantation, rubber plantation, and mixed agriculture). I found that tigers used some plantation areas, although they significantly preferred forests over plantations. In all landcover types, sites with tiger detections had thicker understory cover than sites without tiger detection. Modeling tiger occupancy while recognizing that probability of detection is not always perfect, I found that tiger occupancy covaried positively and significantly with altitude and negatively, but not significantly, with distance-to-forest-cores. Probability of habitat use by tigers covaried positively and significantly with understory cover and altitude, and negatively and significantly with human settlement and landcover rank. The results suggested that with adjustments in plantation management, tigers could use or roam through plantations within the habitat mosaic provided that the plantations had adequate understory cover and low level of human activity. They also could use riparian forests (as corridors) and smaller forest patches (as stepping stones) to travel between the main habitat patches across the forest and plantation landscape.
The third chapter investigates the ecological characteristics and possible inter-specific interactions among wild felids, including tigers and smaller cats, based on data collected using systematic camera trapping in combination with information on their natural history. I found that despite overlap in resource needs of the five felid species, each appears adapted to specific environmental conditions allowing coexistence with other felids. The five felid species used statistically different elevations, with the golden cat found to inhabit the highest elevation. Two-species occupancy models showed that all possible pairs of felid species tended to co-occur more frequently than expected by chance, indicating the tendency of every felid pair to maintain spatial coexistence rather than exclusion. Species of similar size or eating similar-sized prey generally tended to have low coefficients of temporal activity overlap, suggesting avoidance. Temporal avoidance is likely occurring in three pairs of felids, namely clouded leopards and golden cats, clouded leopards and marbled cats, and marbled cats and leopard cats. Based on the differences in morphological and ecological characteristics, and on patterns of spatial and temporal occurrence, I identified six possible mechanisms by which felids in Central Sumatra maintain coexistence. I discussed the implications of this study for management, focusing on how to balance diversity and abundance of felids.
The fourth chapter presents the tiger distribution models as a case study to illustrate the importance of accounting for uncertainty in species distribution mapping. I applied four modeling approaches, differing in how the response variable (tiger presence) is constructed and used in the models. I compared the performance and output of different models based on the relative importance of variables, descriptive statistics of the predictions, cross comparison between models using an error matrix, and validation using tiger presence data collected from independent surveys. All models consistently identified forest area within the grid as one of the most important variables explaining tiger probability of occurrence. Three models identified altitude as another important factor. While the four models were consistent in predicting relatively high probability of tiger occurrence for high elevation forest areas such as Rimbang Baling and Bukit Tigapuluh, they generally had a lower level of agreement in predictions for low elevation areas, particularly the peat land in the northeastern part of the study area. Based on the results of cross evaluation of the predictions among models and validation with the independent data, I considered the occupancy model to be superior to the others. If data collection format permits, I advocate the use of occupancy instead of the other modeling techniques to develop predictive species distribution maps.
The last chapter constructs a strategy to restore the tiger population across the ecosystem of Central Sumatra through integration of knowledge on tiger ecology from previous chapters with consideration of the ecological conditions of the landscape in the region. The strategy combines existing knowledge of tiger conservation and regional ecosystem restoration. It recognizes the limitations and challenges of traditional nature protection and considers existing and new opportunities. Emerging opportunities and new mechanisms, such as direct and indirect economic incentives for nature conservation and restoration, are taken into account. These, coupled with increased awareness of the stakeholders, better policies and implementation of good governance, and the willingness and know-how to maintain coexistence with wildlife among the local people, are expected to support and accelerate the recovery of tigers and their ecosystem.
Berawal dari sebuah diskusi ringan di Pekanbaru, Riau, buku "Rajut Belang" tergagas. Saat itu, Su... more Berawal dari sebuah diskusi ringan di Pekanbaru, Riau, buku "Rajut Belang" tergagas. Saat itu, Suhandri dan Sunarto, yang mengawali diskusi, melihat adanya kebutuhan semacam panduan bagi perusahaan untuk mendukung berbagai upaya konservasi harimau sumatera. Ide pun terus bergulir. Sejumlah pihak memberikan dukungan terhadap rencana tersebut, termasuk Nazir Foead, Direktur Kebijakan WWF-Indonesia dan Dr. Hadi S.
Papers by Sunarto Sunarto
Ecology letters, Jan 17, 2018
The composition of local mammalian carnivore communities has far-reaching effects on terrestrial ... more The composition of local mammalian carnivore communities has far-reaching effects on terrestrial ecosystems worldwide. To better understand how carnivore communities are structured, we analysed camera trap data for 108 087 trap days across 12 countries spanning five continents. We estimate local probabilities of co-occurrence among 768 species pairs from the order Carnivora and evaluate how shared ecological traits correlate with probabilities of co-occurrence. Within individual study areas, species pairs co-occurred more frequently than expected at random. Co-occurrence probabilities were greatest for species pairs that shared ecological traits including similar body size, temporal activity pattern and diet. However, co-occurrence decreased as compared to other species pairs when the pair included a large-bodied carnivore. Our results suggest that a combination of shared traits and top-down regulation by large carnivores shape local carnivore communities globally.
Journal of Zoology, 2015
At least six species of wild cats live in Sumatra. Many are globally threatened and yet their eco... more At least six species of wild cats live in Sumatra. Many are globally threatened and yet their ecology is poorly understood. We investigated ecological characteristics and spatial and temporal overlap among cats in central Sumatra using data from systematic and opportunistic camera trapping in five major forest blocks. We developed occupancy models assessing probability of site use by each cat based on (1) photo-trap rates of other species at the same locations and (2) landscape-level factors extracted from geographic information systems. We also used two-species co-occurrence models to assess spatial overlap and used kernel density estimates on circular data to assess temporal overlap between species pairs. We photographed five cat species: Sumatran tigers, Sunda clouded leopards, Asiatic golden cats, marbled cats and leopard cats. Four cats were present in all sampling blocks and one sampling block had all five cats. Spatially, cat distributions varied among forest types, within the sampling blocks and across elevation. We placed camera traps at elevations ranging from 6 to 460 m above sea level. The five cats used statistically different elevations, with golden cats found at highest elevation. Site use by tigers and leopard cats negatively covaried with distance to protected areas. Clouded leopard presence covaried positively with altitude. Leopard cat presence covaried with the photo-trap rate of tigers, whereas the presence of tigers covaried with the photo-trap rate of non-cat carnivores. We found little evidence of spatial avoidance among cats at camera sites. Temporally, species more similar in size, or with similar-sized prey, had lower overlap, suggesting temporal avoidance. We identified six mechanisms promoting coexistence of central Sumatra cats. Knowledge of interspecific interactions may improve the effectiveness of management aimed at conserving the increasingly threatened wild cat community. bs_bs_banner
Oryx, 2013
Information on spatial and temporal variation in abundance is crucial for effective management of... more 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 Nilo 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 km2) was estimated in the hilly lowland forest of Rimbang Baling and the highest (0.87 ± SE 0.33 per 100 km2) in the flat lowland forest of the P...
PloS one, 2010
Background: The flat-headed cat (Prionailurus planiceps) is one of the world's least known, highl... more Background: The flat-headed cat (Prionailurus planiceps) is one of the world's least known, highly threatened felids with a distribution restricted to tropical lowland rainforests in Peninsular Thailand/Malaysia, Borneo and Sumatra. Throughout its geographic range large-scale anthropogenic transformation processes, including the pollution of fresh-water river systems and landscape fragmentation, raise concerns regarding its conservation status. Despite an increasing number of cameratrapping field surveys for carnivores in South-East Asia during the past two decades, few of these studies recorded the flatheaded cat.
At least six species of wild cats live in Sumatra. Many are globally threatened and yet their eco... more At least six species of wild cats live in Sumatra. Many are globally threatened and yet their ecology is poorly understood. We investigated ecological characteristics and spatial and temporal overlap among cats in central Sumatra using
data from systematic and opportunistic camera trapping in five major forest blocks. We developed occupancy models assessing probability of site use by each cat based on (1) photo-trap rates of other species at the same locations and (2) landscape-level factors extracted from geographic information systems. We also used two-species co-occurrence models to assess spatial overlap and used kernel density estimates on circular data to assess temporal overlap between species pairs. We photographed five cat species: Sumatran tigers, Sunda clouded leopards, Asiatic golden cats, marbled cats and leopard cats. Four cats were present in all sampling blocks and one sampling block had all five cats. Spatially, cat distributions varied among forest types, within the sampling blocks and across
elevation. We placed camera traps at elevations ranging from 6 to 460 m above sea level. The five cats used statistically different elevations, with golden cats found at highest elevation. Site use by tigers and leopard cats negatively covaried
with distance to protected areas. Clouded leopard presence covaried positively
with altitude. Leopard cat presence covaried with the photo-trap rate of tigers,
whereas the presence of tigers covaried with the photo-trap rate of non-cat carnivores.
We found little evidence of spatial avoidance among cats at camera sites.
Temporally, species more similar in size, or with similar-sized prey, had lower
overlap, suggesting temporal avoidance. We identified six mechanisms promoting
coexistence of central Sumatra cats. Knowledge of interspecific interactions
may improve the effectiveness of management aimed at conserving the increasingly
threatened wild cat community.
PloS one, Jan 1, 2011
Large carnivores living in tropical rainforests are under immense pressure from the rapid convers... more 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 (17617 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 = 0.1360.017; 6S.E.), the estimated tiger occupancy was 0.7260.048. 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 (0.3360.055). 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.
PloS one, Jan 1, 2012
The critically endangered Sumatran tiger (Panthera tigris sumatrae Pocock, 1929) is generally kno... more 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.
Conservation …, Jan 1, 2011
In an unprecedented response to the rapid decline in wild tiger populations,
the Heads of Governm... more In an unprecedented response to the rapid decline in wild tiger populations,
the Heads of Government of the 13 tiger range countries endorsed the St. Petersburg
Declaration in November 2010, pledging to double the wild tiger population.
We conducted a landscape analysis of tiger habitat to determine if a
recovery of such magnitude is possible. The reserves in 20 priority tiger landscapes
can potentially support >10,000 tigers, almost thrice the current estimate.
However, most core reserves where tigers breed are small and land-use
change in rapidly developing Asia threatens to increase reserve and population
isolation. Maintaining population viability and resilience will depend upon a
landscape approach to manage tigers as metapopulations. Thus, both site-level
protection and landscape-scale interventions to secure habitat corridors are
simultaneous imperatives. Co-benefits, such as payment schemes for carbon
and other ecosystem services, should be employed as strategies to mainstream
landscape conservation in tiger habitat into development processes.
PloS one, Jan 1, 2010
Background: The flat-headed cat (Prionailurus planiceps) is one of the world's least known, highl... more Background: The flat-headed cat (Prionailurus planiceps) is one of the world's least known, highly threatened felids with a distribution restricted to tropical lowland rainforests in Peninsular Thailand/Malaysia, Borneo and Sumatra. Throughout its geographic range large-scale anthropogenic transformation processes, including the pollution of fresh-water river systems and landscape fragmentation, raise concerns regarding its conservation status. Despite an increasing number of cameratrapping field surveys for carnivores in South-East Asia during the past two decades, few of these studies recorded the flatheaded cat.
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Books by Sunarto Sunarto
Long-term survival of Sumatran tigers depends largely on the effectiveness of current conservation efforts in every tiger landscape. Successful conservation and management require accurate information on ecology of the species upon which decisions can be based. This study investigated basic ecological aspects of tigers and developed strategies for management and restoration to improve tiger viability in the Central Sumatra landscape. This landscape is comprised of natural forests and plantations managed for timber and agricultural commodities.
The first chapter assesses the variation in tiger abundance across forest types in Southern Riau, and over time in Tesso Nilo National Park, all in Central Sumatra. Using camera traps, my team and I systematically sampled five blocks representing three major forest types in the region: peat land, flat lowland, and hilly lowland. I found that tiger abundance varied by forest type and through time. Excluding two sampling blocks where no tigers were photographed, the lowest tiger density was in peat land forest of Kerumutan, and the highest density was in the flat lowland forest of Tesso Nilo. Repeated sampling in the newly established Tesso Nilo National Park documented a trend of increasing tiger density (SE) from 0.90 (0.38) individuals/100 km2 in 2005 to 1.70 (0.66) individuals/100 km2 in 2008. Overall, tiger densities from this study were lower than most previous estimates from other parts of Sumatra. The trend of increasing tiger density in Tesso Nilo, however, suggests that the tiger population could be augmented by protection of habitats that were previously logged and severely disturbed.
The second chapter examines the occupancy and habitat-use of the tiger across the major landcover types (natural forest, acacia plantation, oilpalm plantation, rubber plantation, and mixed agriculture). I found that tigers used some plantation areas, although they significantly preferred forests over plantations. In all landcover types, sites with tiger detections had thicker understory cover than sites without tiger detection. Modeling tiger occupancy while recognizing that probability of detection is not always perfect, I found that tiger occupancy covaried positively and significantly with altitude and negatively, but not significantly, with distance-to-forest-cores. Probability of habitat use by tigers covaried positively and significantly with understory cover and altitude, and negatively and significantly with human settlement and landcover rank. The results suggested that with adjustments in plantation management, tigers could use or roam through plantations within the habitat mosaic provided that the plantations had adequate understory cover and low level of human activity. They also could use riparian forests (as corridors) and smaller forest patches (as stepping stones) to travel between the main habitat patches across the forest and plantation landscape.
The third chapter investigates the ecological characteristics and possible inter-specific interactions among wild felids, including tigers and smaller cats, based on data collected using systematic camera trapping in combination with information on their natural history. I found that despite overlap in resource needs of the five felid species, each appears adapted to specific environmental conditions allowing coexistence with other felids. The five felid species used statistically different elevations, with the golden cat found to inhabit the highest elevation. Two-species occupancy models showed that all possible pairs of felid species tended to co-occur more frequently than expected by chance, indicating the tendency of every felid pair to maintain spatial coexistence rather than exclusion. Species of similar size or eating similar-sized prey generally tended to have low coefficients of temporal activity overlap, suggesting avoidance. Temporal avoidance is likely occurring in three pairs of felids, namely clouded leopards and golden cats, clouded leopards and marbled cats, and marbled cats and leopard cats. Based on the differences in morphological and ecological characteristics, and on patterns of spatial and temporal occurrence, I identified six possible mechanisms by which felids in Central Sumatra maintain coexistence. I discussed the implications of this study for management, focusing on how to balance diversity and abundance of felids.
The fourth chapter presents the tiger distribution models as a case study to illustrate the importance of accounting for uncertainty in species distribution mapping. I applied four modeling approaches, differing in how the response variable (tiger presence) is constructed and used in the models. I compared the performance and output of different models based on the relative importance of variables, descriptive statistics of the predictions, cross comparison between models using an error matrix, and validation using tiger presence data collected from independent surveys. All models consistently identified forest area within the grid as one of the most important variables explaining tiger probability of occurrence. Three models identified altitude as another important factor. While the four models were consistent in predicting relatively high probability of tiger occurrence for high elevation forest areas such as Rimbang Baling and Bukit Tigapuluh, they generally had a lower level of agreement in predictions for low elevation areas, particularly the peat land in the northeastern part of the study area. Based on the results of cross evaluation of the predictions among models and validation with the independent data, I considered the occupancy model to be superior to the others. If data collection format permits, I advocate the use of occupancy instead of the other modeling techniques to develop predictive species distribution maps.
The last chapter constructs a strategy to restore the tiger population across the ecosystem of Central Sumatra through integration of knowledge on tiger ecology from previous chapters with consideration of the ecological conditions of the landscape in the region. The strategy combines existing knowledge of tiger conservation and regional ecosystem restoration. It recognizes the limitations and challenges of traditional nature protection and considers existing and new opportunities. Emerging opportunities and new mechanisms, such as direct and indirect economic incentives for nature conservation and restoration, are taken into account. These, coupled with increased awareness of the stakeholders, better policies and implementation of good governance, and the willingness and know-how to maintain coexistence with wildlife among the local people, are expected to support and accelerate the recovery of tigers and their ecosystem.
Papers by Sunarto Sunarto
data from systematic and opportunistic camera trapping in five major forest blocks. We developed occupancy models assessing probability of site use by each cat based on (1) photo-trap rates of other species at the same locations and (2) landscape-level factors extracted from geographic information systems. We also used two-species co-occurrence models to assess spatial overlap and used kernel density estimates on circular data to assess temporal overlap between species pairs. We photographed five cat species: Sumatran tigers, Sunda clouded leopards, Asiatic golden cats, marbled cats and leopard cats. Four cats were present in all sampling blocks and one sampling block had all five cats. Spatially, cat distributions varied among forest types, within the sampling blocks and across
elevation. We placed camera traps at elevations ranging from 6 to 460 m above sea level. The five cats used statistically different elevations, with golden cats found at highest elevation. Site use by tigers and leopard cats negatively covaried
with distance to protected areas. Clouded leopard presence covaried positively
with altitude. Leopard cat presence covaried with the photo-trap rate of tigers,
whereas the presence of tigers covaried with the photo-trap rate of non-cat carnivores.
We found little evidence of spatial avoidance among cats at camera sites.
Temporally, species more similar in size, or with similar-sized prey, had lower
overlap, suggesting temporal avoidance. We identified six mechanisms promoting
coexistence of central Sumatra cats. Knowledge of interspecific interactions
may improve the effectiveness of management aimed at conserving the increasingly
threatened wild cat community.
the Heads of Government of the 13 tiger range countries endorsed the St. Petersburg
Declaration in November 2010, pledging to double the wild tiger population.
We conducted a landscape analysis of tiger habitat to determine if a
recovery of such magnitude is possible. The reserves in 20 priority tiger landscapes
can potentially support >10,000 tigers, almost thrice the current estimate.
However, most core reserves where tigers breed are small and land-use
change in rapidly developing Asia threatens to increase reserve and population
isolation. Maintaining population viability and resilience will depend upon a
landscape approach to manage tigers as metapopulations. Thus, both site-level
protection and landscape-scale interventions to secure habitat corridors are
simultaneous imperatives. Co-benefits, such as payment schemes for carbon
and other ecosystem services, should be employed as strategies to mainstream
landscape conservation in tiger habitat into development processes.
Long-term survival of Sumatran tigers depends largely on the effectiveness of current conservation efforts in every tiger landscape. Successful conservation and management require accurate information on ecology of the species upon which decisions can be based. This study investigated basic ecological aspects of tigers and developed strategies for management and restoration to improve tiger viability in the Central Sumatra landscape. This landscape is comprised of natural forests and plantations managed for timber and agricultural commodities.
The first chapter assesses the variation in tiger abundance across forest types in Southern Riau, and over time in Tesso Nilo National Park, all in Central Sumatra. Using camera traps, my team and I systematically sampled five blocks representing three major forest types in the region: peat land, flat lowland, and hilly lowland. I found that tiger abundance varied by forest type and through time. Excluding two sampling blocks where no tigers were photographed, the lowest tiger density was in peat land forest of Kerumutan, and the highest density was in the flat lowland forest of Tesso Nilo. Repeated sampling in the newly established Tesso Nilo National Park documented a trend of increasing tiger density (SE) from 0.90 (0.38) individuals/100 km2 in 2005 to 1.70 (0.66) individuals/100 km2 in 2008. Overall, tiger densities from this study were lower than most previous estimates from other parts of Sumatra. The trend of increasing tiger density in Tesso Nilo, however, suggests that the tiger population could be augmented by protection of habitats that were previously logged and severely disturbed.
The second chapter examines the occupancy and habitat-use of the tiger across the major landcover types (natural forest, acacia plantation, oilpalm plantation, rubber plantation, and mixed agriculture). I found that tigers used some plantation areas, although they significantly preferred forests over plantations. In all landcover types, sites with tiger detections had thicker understory cover than sites without tiger detection. Modeling tiger occupancy while recognizing that probability of detection is not always perfect, I found that tiger occupancy covaried positively and significantly with altitude and negatively, but not significantly, with distance-to-forest-cores. Probability of habitat use by tigers covaried positively and significantly with understory cover and altitude, and negatively and significantly with human settlement and landcover rank. The results suggested that with adjustments in plantation management, tigers could use or roam through plantations within the habitat mosaic provided that the plantations had adequate understory cover and low level of human activity. They also could use riparian forests (as corridors) and smaller forest patches (as stepping stones) to travel between the main habitat patches across the forest and plantation landscape.
The third chapter investigates the ecological characteristics and possible inter-specific interactions among wild felids, including tigers and smaller cats, based on data collected using systematic camera trapping in combination with information on their natural history. I found that despite overlap in resource needs of the five felid species, each appears adapted to specific environmental conditions allowing coexistence with other felids. The five felid species used statistically different elevations, with the golden cat found to inhabit the highest elevation. Two-species occupancy models showed that all possible pairs of felid species tended to co-occur more frequently than expected by chance, indicating the tendency of every felid pair to maintain spatial coexistence rather than exclusion. Species of similar size or eating similar-sized prey generally tended to have low coefficients of temporal activity overlap, suggesting avoidance. Temporal avoidance is likely occurring in three pairs of felids, namely clouded leopards and golden cats, clouded leopards and marbled cats, and marbled cats and leopard cats. Based on the differences in morphological and ecological characteristics, and on patterns of spatial and temporal occurrence, I identified six possible mechanisms by which felids in Central Sumatra maintain coexistence. I discussed the implications of this study for management, focusing on how to balance diversity and abundance of felids.
The fourth chapter presents the tiger distribution models as a case study to illustrate the importance of accounting for uncertainty in species distribution mapping. I applied four modeling approaches, differing in how the response variable (tiger presence) is constructed and used in the models. I compared the performance and output of different models based on the relative importance of variables, descriptive statistics of the predictions, cross comparison between models using an error matrix, and validation using tiger presence data collected from independent surveys. All models consistently identified forest area within the grid as one of the most important variables explaining tiger probability of occurrence. Three models identified altitude as another important factor. While the four models were consistent in predicting relatively high probability of tiger occurrence for high elevation forest areas such as Rimbang Baling and Bukit Tigapuluh, they generally had a lower level of agreement in predictions for low elevation areas, particularly the peat land in the northeastern part of the study area. Based on the results of cross evaluation of the predictions among models and validation with the independent data, I considered the occupancy model to be superior to the others. If data collection format permits, I advocate the use of occupancy instead of the other modeling techniques to develop predictive species distribution maps.
The last chapter constructs a strategy to restore the tiger population across the ecosystem of Central Sumatra through integration of knowledge on tiger ecology from previous chapters with consideration of the ecological conditions of the landscape in the region. The strategy combines existing knowledge of tiger conservation and regional ecosystem restoration. It recognizes the limitations and challenges of traditional nature protection and considers existing and new opportunities. Emerging opportunities and new mechanisms, such as direct and indirect economic incentives for nature conservation and restoration, are taken into account. These, coupled with increased awareness of the stakeholders, better policies and implementation of good governance, and the willingness and know-how to maintain coexistence with wildlife among the local people, are expected to support and accelerate the recovery of tigers and their ecosystem.
data from systematic and opportunistic camera trapping in five major forest blocks. We developed occupancy models assessing probability of site use by each cat based on (1) photo-trap rates of other species at the same locations and (2) landscape-level factors extracted from geographic information systems. We also used two-species co-occurrence models to assess spatial overlap and used kernel density estimates on circular data to assess temporal overlap between species pairs. We photographed five cat species: Sumatran tigers, Sunda clouded leopards, Asiatic golden cats, marbled cats and leopard cats. Four cats were present in all sampling blocks and one sampling block had all five cats. Spatially, cat distributions varied among forest types, within the sampling blocks and across
elevation. We placed camera traps at elevations ranging from 6 to 460 m above sea level. The five cats used statistically different elevations, with golden cats found at highest elevation. Site use by tigers and leopard cats negatively covaried
with distance to protected areas. Clouded leopard presence covaried positively
with altitude. Leopard cat presence covaried with the photo-trap rate of tigers,
whereas the presence of tigers covaried with the photo-trap rate of non-cat carnivores.
We found little evidence of spatial avoidance among cats at camera sites.
Temporally, species more similar in size, or with similar-sized prey, had lower
overlap, suggesting temporal avoidance. We identified six mechanisms promoting
coexistence of central Sumatra cats. Knowledge of interspecific interactions
may improve the effectiveness of management aimed at conserving the increasingly
threatened wild cat community.
the Heads of Government of the 13 tiger range countries endorsed the St. Petersburg
Declaration in November 2010, pledging to double the wild tiger population.
We conducted a landscape analysis of tiger habitat to determine if a
recovery of such magnitude is possible. The reserves in 20 priority tiger landscapes
can potentially support >10,000 tigers, almost thrice the current estimate.
However, most core reserves where tigers breed are small and land-use
change in rapidly developing Asia threatens to increase reserve and population
isolation. Maintaining population viability and resilience will depend upon a
landscape approach to manage tigers as metapopulations. Thus, both site-level
protection and landscape-scale interventions to secure habitat corridors are
simultaneous imperatives. Co-benefits, such as payment schemes for carbon
and other ecosystem services, should be employed as strategies to mainstream
landscape conservation in tiger habitat into development processes.