A Supplemental HCVF Assessment on the Sumatran Tiger ...

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FINAL REPORT Tiger <strong>HCVF</strong> <strong>Supplemental</strong> <strong>Assessment</strong> – Serapung FMU (Smith et al. 1989). In PSF the localised concentration of tiger activity as suggested by secondary signs and “scent-marking” may be accentuated as undisturbed PSF is more restricting in terms of ease-of-movement in comparison to other lowland forest types. The paths along the canals within the FMU offer the same ease-of-movement but, being newly developed and subject to intense disturbance from illegal logging, may not yet be fully exploited by tigers. Previous studies have shown some species, including tigers, become more nocturnal in their activity in order to avoid encounters with humans (Ojasti 1991, Griffiths and van Schaik 1993, Guggisberg 1975) and Kawanishi (2002). The relative abundance of tiger sign found within and outside the FMU was also reflected in the number of remote camera photographs obtained, with all 14 photographs taken along the Yos Trail. However, it should be noted that the number of camera trap days was 50% greater along the Yos Trail in comparison to the FMU, due to theft of cameras within the FMU and a limited number of locations where cameras could be placed due to illegal logging activities. The rate of photo-capture for all cameras both inside and outside the FMU was 0.093 tiger photographs per camera day (10.7 days/photograph). Comparison with other studies (Figure 23) identifies this as the highest rate achieved by any published study on the Sumatran tiger in Indonesia, greater than capture rates from the high-density tiger population in Way Kambas NP (0.025 photographs/camera day, 39.9 days/photograph) and comparable to capture rates achieved in the exceptionally high tiger density areas of India and Nepal’s flagship national parks (including Kaziranga, Nagarahole and Chitwan). Although photographic capture rates of tigers have been shown to be correlated with their density (Carbone et al. 2001), due to limitations of study time and camera coverage, no attempt is made here to relate results to such estimates of density. An accepted minimum level of sampling effort for such an extrapolation is considered to be 1,000 camera trap days (Carbone et al. 2001) which, under the study conditions of this assessment, would require extension of field time by a factor of 9. However, photographic capture rates were qualitatively similar to rates found in other quality habitats of Sumatra, at least suggesting that tiger density in Serapung is not outside the range of density previously observed elsewhere. If the high frequency of tiger secondary signs and photo-captures is considered alongside the frequent reports of tiger sightings by local people, it is clear that tigers are exceptionally active around the Serapung FMU and particularly within the immediate vicinity of the Yos Trail. Further study is required to confirm that these high levels of tiger activity relate to a corresponding high tiger density, or whether this abundance of data is a result of the geographically restricted ranging of a smaller number of individuals. However, during the time available this assessment could find no evidence in support of the latter hypothesis, where no obvious boundaries to tiger movement were observed, and where no qualitative differences in habitat could be identified between the Yos Trail and adjacent areas. Given the overwhelming weight of evidence collected during this assessment, it appears that the peat swamp forests of Serapung and Siak-Pelalawan provide tiger habitat at least comparable to other optimal lowland forests sites in Sumatra. Further work should be conducted as a matter of urgency to accurately measure the carrying-capacity of PSF in relation to the Sumatran tiger. Evidence collected during this assessment, in contrast to previous studies, suggests that PSF should not be considered suboptimal habitat for tigers as a general rule. If tigers are confirmed to be capable of living at high densities in PSF then this will have a significant impact on future Sumatra-wide conservation strategies for the species. Sumatran Tiger Conservation Program Pg 46/68
FINAL REPORT Tiger <strong>HCVF</strong> <strong>Supplemental</strong> <strong>Assessment</strong> – Serapung FMU No evidence of tiger secondary signs were encountered in the FMU outside of the forested moratorium area (i.e. in cleared areas or within plots planted with Acacia). However, in the small forested area to the south-east of the FMU (Tandjung Datuk) credible eye-witness accounts indicated tiger presence up through and including late 2004. Given this it must be assumed that tigers continue to traverse the strip of forest (designated Unggulan and Konservasi by APP) along the south-eastern boundary of the FMU. Similar reliable accounts of recent sightings were received for northern areas of the FMU which have only recently been clear-felled, including reliable reports of a company contract employee being killed, and one other injured, due to tiger attacks occurring as recently as October 2004. Serapung Indonesia Kerinci Seblat Indonesia Bukit Barisan Selatan Indonesia Gunung Leuser Indonesia Way Kambas Indonesia Taman Negara Malaysia Ulu Temaing Forest Malaysia Gunung Tebu Forest Malaysia Bintang Hijau Forest Malaysia Temenggor Forest Malaysia Khao Yai National Thailand Phu Khieo Wildlife Thailand Queen Sirikit Reserve Thailand Halabala Thailand Chitwan Nepal Bandhavgarh India Pench India Nagarahole India Kaziranga India Kanha India 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 No. of photos per camera day Figure 23. The number of tiger photographs per camera day in Serapung compared to other previous field studies (Carbone et al. 2001). The photo-capture rate in Serapung is greater than all other studies on the Sumatran tiger (shown in red), and is comparable to data collected for the Bengal tiger in locations where they are known to live at high densities. 5.3 Tiger Viability Issues in the FMU and Siak-Pelalawan Landscape An evaluation of the future potential and viability of the tiger population inhabiting the FMU and the Siak-Pelalawan block necessitates consideration of habitat availability in the wider landscape. For the purposes of this analysis all natural forest in the Siak- Pelalawan block is considered to represent habitat currently utilised by tigers. In contrast HTI plantations are not assumed to provide any significant contribution to maintenance of tigers except in the case where large conservation areas have been set-aside. Oil-palm estates, at least in the first years of growth and when located adjacent to natural forest, do support an elevated density of ungulates and wild pigs when compared to natural forests. However, evidence currently suggests that tigers only utilise the fringes of these oil-palm plantations while hunting, relying on adjacent forests for all other aspects of their behaviour and ecology. For this reason, and for the Sumatran Tiger Conservation Program Pg 47/68
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