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Matthew Linkie - One of the best experts on this subject based on the ideXlab platform.
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Estimated Sumatran Tiger site occupancy and sites with actual indirect Tiger sign detections (black dots).
2013Co-Authors: Hariyo T Wibisono, Wulan Pusparini, Matthew Linkie, Gurutzeta Guillera-arroita, Joseph A. Smith, Pandu Baroto, Nick Brickle, Yoan DinataAbstract:Estimated Sumatran Tiger site occupancy and sites with actual indirect Tiger sign detections (black dots).
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population status of a cryptic top predator an island wide assessment of Tigers in Sumatran rainforests
PLOS ONE, 2011Co-Authors: Hariyo T Wibisono, Wulan Pusparini, Matthew Linkie, Pandu Baroto, Nick Brickle, Gurutzeta Guilleraarroita, Joseph Smith, Yoan DinataAbstract: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.
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Species Occupancy Modeling for Detection Data Collected Along a Transect
Journal of Agricultural Biological and Environmental Statistics, 2011Co-Authors: Gurutzeta Guillera-arroita, Martin S Ridout, Byron J. T. Morgan, Matthew LinkieAbstract:The proportion of sampling sites occupied by a species is a concept of interest in ecology and biodiversity conservation. Occupancy surveys based on collecting detection data along transects have become increasingly popular to monitor some species. To date, the analysis of such data has been carried out by discretizing the data, dividing the transects into discrete segments. Here we propose alternative occupancy models which describe the detection process as a continuous point process. These models provide a more natural description of the data and eliminate the need to divide transects into segments, which can be arbitrary and may lead to increased bias in the estimator of occupancy or increased chances of obtaining estimates on the boundary of the parameter space. We present a model that assumes independence between detections and an alternative model that describes the detection process as a Markov modulated Poisson process to account for potential clustering in the detections. The utility of these models is illustrated with the analysis of data from a recent survey of the Sumatran Tiger Panthera tigris sumatrae . The models can also be applied to surveys that collect continuous data in time, such as those based on the use of camera-trap devices. Supplementary materials for this article are available online.
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assessing Tiger prey interactions in Sumatran rainforests
Journal of Zoology, 2011Co-Authors: Matthew Linkie, Martin S RidoutAbstract:Little is known about interactions between the critically endangered Sumatran Tiger Panthera tigris sumatrae and its prey because of the difficulties associated with detecting these species. In this study, we quantify temporal overlap between the Sumatran Tiger and five of its presumed prey species from four study areas comprising disturbed lowland to primary submontane forest. Data from 126 camera traps over 8984 camera days were used to estimate species activity patterns and, in turn, their overlap through the coefficient Δ (ranging from 0 to 1, i.e. no overlap to complete overlap). A newly developed statistical technique was applied to determine confidence intervals associated with respective overlap, which is important, as such measures of precision are usually not estimated in these types of study. Strong temporal overlap was found between Tiger and muntjac Muntiacus muntjac (Δ=0.80, 95%CI=0.71–0.84) and Tiger and sambar Cervus unicolor (Δ=0.81, 0.55–0.85), with the latter illustrating the importance of measuring precision. According to the foraging theory, Sumatran Tigers should focus on expending lower levels of energy searching for and then capturing larger bodied prey that present the least risk. Hence, surprisingly, there was little overlap between the crepuscular Tiger and the largest-bodied prey species available, the nocturnal tapir Tapirus indicus (0.52, 0.44–0.60), suggesting that it is not a principal prey species. This study provides the first insights into Sumatran Tiger–prey temporal interactions. The ability to estimate overlap statistics with measures of precision has obvious and wide benefits for other predator–prey and interspecific competition studies.
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allocating conservation resources between areas where persistence of a species is uncertain
Ecological Applications, 2011Co-Authors: Michael A. Mccarthy, Iadine Chadès, Matthew Linkie, Eve Mcdonaldmadden, Hugh P. PossinghamAbstract:Research on the allocation of resources to manage threatened species typically assumes that the state of the system is completely observable; for example whether a species is present or not. The majority of this research has converged on modeling problems as Markov decision processes (MDP), which give an optimal strategy driven by the current state of the system being managed. However, the presence of threatened species in an area can be uncertain. Typically, resource allocation among multiple conservation areas has been based on the biggest expected benefit (return on investment) but fails to incorporate the risk of imperfect detection. We provide the first decision-making framework for confronting the trade-off between information and return on investment, and we illustrate the approach for populations of the Sumatran Tiger (Panthera tigris sumatrae) in Kerinci Seblat National Park. The problem is posed as a partially observable Markov decision process (POMDP), which extends MDP to incorporate incomplete detection and allows decisions based on our confidence in particular states. POMDP has previously been used for making optimal management decisions for a single population of a threatened species. We extend this work by investigating two populations, enabling us to explore the importance of variation in expected return on investment between populations on how we should act. We compare the performance of optimal strategies derived assuming complete (MDP) and incomplete (POMDP) observability. We find that uncertainty about the presence of a species affects how we should act. Further, we show that assuming full knowledge of a species presence will deliver poorer strategic outcomes than if uncertainty about a species status is explicitly considered. MDP solutions perform up to 90% worse than the POMDP for highly cryptic species, and they only converge in performance when we are certain of observing the species during management: an unlikely scenario for many threatened species. This study illustrates an approach to allocating limited resources to threatened species where the conservation status of the species in different areas is uncertain. The results highlight the importance of including partial observability in future models of optimal species management when the species of concern is cryptic in nature.
Yoan Dinata - One of the best experts on this subject based on the ideXlab platform.
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Estimated Sumatran Tiger site occupancy and sites with actual indirect Tiger sign detections (black dots).
2013Co-Authors: Hariyo T Wibisono, Wulan Pusparini, Matthew Linkie, Gurutzeta Guillera-arroita, Joseph A. Smith, Pandu Baroto, Nick Brickle, Yoan DinataAbstract:Estimated Sumatran Tiger site occupancy and sites with actual indirect Tiger sign detections (black dots).
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population status of a cryptic top predator an island wide assessment of Tigers in Sumatran rainforests
PLOS ONE, 2011Co-Authors: Hariyo T Wibisono, Wulan Pusparini, Matthew Linkie, Pandu Baroto, Nick Brickle, Gurutzeta Guilleraarroita, Joseph Smith, Yoan DinataAbstract: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.
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The existence of Sumatran Tiger (Panthera tigris sumatrae Pocock, 1929) and their prey in different forest habitat types in Kerinci Seblat National Park, Sumatra
MBI & UNS Solo, 2008Co-Authors: Yoan Dinata, Jito SugardjitoAbstract:A study on the relationships between prey animals and the occurence of Sumatran Tiger was conducted in Kerinci Seblat National Park, western Sumatra from May up to September 2001. The data have been collected from eight study sites based on the forest habitat types and its threats. The results showed that frequency of encounters with prey animals in different forest habitats were no difference. This might indicates that the prey animals were distributed fairly in all types of forest habitat. The frequency encounters of the Sumatran Tiger signs, however, have shown differently between locations. The encounters of Tiger signs were more frequent in the forest habitats that close to the streams; in forest habitats with few animal huntings; and in forest habitats with no logging activities. This findings support the hypotheses that the existence of Sumatran Tiger as a predator is determined by the dense vegetations surrounding streams as hiding place used in an ambush; availability of prey animals as food, and habitat disturbances as shown by logging
Wulan Pusparini - One of the best experts on this subject based on the ideXlab platform.
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Estimated Sumatran Tiger site occupancy and sites with actual indirect Tiger sign detections (black dots).
2013Co-Authors: Hariyo T Wibisono, Wulan Pusparini, Matthew Linkie, Gurutzeta Guillera-arroita, Joseph A. Smith, Pandu Baroto, Nick Brickle, Yoan DinataAbstract:Estimated Sumatran Tiger site occupancy and sites with actual indirect Tiger sign detections (black dots).
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population status of a cryptic top predator an island wide assessment of Tigers in Sumatran rainforests
PLOS ONE, 2011Co-Authors: Hariyo T Wibisono, Wulan Pusparini, Matthew Linkie, Pandu Baroto, Nick Brickle, Gurutzeta Guilleraarroita, Joseph Smith, Yoan DinataAbstract: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.
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Sumatran Tiger panthera tigris sumatrae a review of conservation status
Integrative Zoology, 2010Co-Authors: Hariyo T Wibisono, Wulan PuspariniAbstract:The majority of wild Sumatran Tigers are believed to live in 12 Tiger Conservation Landscapes covering approximately 88 000 km². 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.
Suyadi Suyadi - One of the best experts on this subject based on the ideXlab platform.
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DEFORESTATION AND ITS IMPLICATIONS TO THE POPULATION OF Sumatran Tiger (PANTHERA TIGRIS SUMATRAE) IN BUKIT BARISAN SELATAN NATIONAL PARK, SUMATRA
Badan Informasi Geospasial in Partnership with MAPIN, 2016Co-Authors: Suyadi SuyadiAbstract:Bukit Barisan Selatan National Park (BBSNP) is home for Sumatran Tigers (Panthera tigris sumatrae), one of world’s most endangered mammals (Appendix I of CITES). Much of the forest cover in BBSNP has been cleared dramatically and deforestation is a great threat on the population of Tigers. Remotely-sensed data sets were linked with wildlife survey using camera traps to examine the deforestation from 1998 to 2006 and its effects to the population of Sumatran Tigers in BBSNP. This paper assesses the relationship between deforestation in BBSNP with the population of Sumatran Tigers. It was found that the average rates of forest loss in BBSNP were 18.76 km2 per year, representing a 7% loss from 1998 to 2006. In addition, the number of Tigers declined from 57 Tigers in 2000 to 22 Tigers in 2006, and Tiger density decrease from 2.25 Tigers/100km2 in 2000 to 1.16 Tiger/100km2 in 2006. Keywords: Deforestation, Sumatran Tiger, satellite imageries, Camera Trap, Bukit Barisan Selatan National Park. ABSTRAKTaman Nasional Bukit Barisan Selatan adalah habitat bagi harimau Sumatra (Panthera tigris sumatrae), salah satu mamalia yang terancam keberadaannya (Lampiran I CITES). Banyak hutan yang sudah dibabat secara dramatis dan penggundulan hutan merupakan ancaman yang besar pada populasi harimau. Data penginderaan jauh dikorelasikan dengan survei satwa liar yang menggunakan camera traps untuk mengkaji deforestasi dari tahun 1998 sampai 2006 dan pengaruhnya pada populasi harimau Sumatra dalam wilayah taman nasional tersebut. Makalah ini mengkaji hubungan antara penurunan jumlah hutan dengan populasi harimau Sumatra. Ditemukan bahwa rata-rata kehilangan hutan di taman nasional ini adalah 18,76 km per tahun, sekitar 7% dari tahun 1998 s.d. 2006. Jumlah harimau yang terekam menurun dari 57 di tahun 2000 menjadi 22 tahun 2006, dan populasinya menurun dari 2,25/100km2 di tahun 2000 menjadi 1,16/100km2 tahun 2006. Katakunci: Penggundulan hutan, harimau Sumatra, citra satelit, kamera trap,Taman Nasional Bukit Barisan Selatan
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SPATIAL MODEL OF Sumatran Tiger (Panthera tigris sumatrae) POTENTIAL HABITAT SUITABILITY IN BUKIT BARISAN SELATAN
'Indonesian Institute of Sciences', 2016Co-Authors: Suyadi Suyadi, Jaya, Nengah I Surati, Wijanarto, Antonius B, Wibisono, Haryo TabahAbstract:This study describes on development of habitat suitability for Sumatran Tiger in Bukit Barisan Selatan National Park (BBSNP). In this study remotely-sensed data set were linked with Tiger and it prey survey using camera trap to identify the environmental and human factors that influences the Tiger's potential habitat, and to develop a spatial model as well as in BBSNP. All at once, the study showed that the potential model for estimating the Tiger's potential habitat suitability could be developed using environmental and human factors. The most significant factors that influence the Tiger habitat suitability in Bukit Barisan Selatan National Park are human factors such as distance to road and distance to forest edge and the environmental factor i.e. the number of Tiger prey. The verification of the model shows that the model is capable to estimate the probability of the Tiger presence having accuracy of approximately 78%. The model shows that there is no significant difference between the predicted data and actual data and having mean deviation less than 10%
Jeanmarc Hero - One of the best experts on this subject based on the ideXlab platform.
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faecal cortisol metabolites in bengal panthera tigris tigris and Sumatran Tigers panthera tigris sumatrae
General and Comparative Endocrinology, 2013Co-Authors: Edward Jitik Narayan, Tempe Parnell, Giles Clark, Patrick Martinvegue, Al Mucci, Jeanmarc HeroAbstract:The Tiger (Panthera tigris) faces a great risk of extinction as its wild numbers have plummeted due to poaching and habitat destruction so ex-situ conservation programs are becoming ever more necessary. Reliable non-invasive biomarkers of the stress hormone (cortisol) are necessary for assessing the health and welfare of Tigers in captivity. To our knowledge, non-invasive stress endocrinology methods have not been tested as widely in Tigers. The first aim of this study was to describe and validate a faecal cortisol metabolite enzyme-immmunoassay (FCM EIA) for two Tiger sub-species, the Bengal Tiger (Panthera tigris tigris) and the Sumatran Tiger (Panthera tigris sumatrae). Individual Tigers (n = 22) were studied in two large Zoos in Queensland, Australia (Dreamworld Theme Park and Australia Zoo). Fresh faecal samples ( 89% recovery of the cortisol standard that was added to Tiger faecal extract. We also obtained parallel displacement of the serially diluted cortisol standard against serially diluted Tiger faecal extract. Our second aim was to determine whether the FCM levels were significantly different between Tiger sub-species and sex. Results showed no significant difference in mean FCM levels between the Bengal and Sumatran Tiger sub-species. Mean levels of FCMs were significantly higher in females than in male Tigers. Those male and female Tigers with reported health issues during the study period expressed higher FCM levels than the reportedly healthy Tigers. Interestingly, those Tigers that took part in some activity (such as walks, photos, presentations and guest feeds) expressed moderately higher FCM levels at Dreamworld and lower FCM levels at Australia Zoo in comparison to those Tigers that did not take part in such activities. These results indicate potential habituation in some Tigers for routine activity through specialized training and pre-conditioning. In conclusion, the FCM EIA described in this study provides a reliable non-invasive method for evaluating the stress status of Tigers in Zoos.
