A Supplemental HCVF Assessment on the Sumatran Tiger ...

FINAL REPORT Tiger <strong>HCVF</strong> <strong>Supplemental</strong> <strong>Assessment</strong> – Serapung FMU
3.4 Remote Camera Monitoring of Tigers and Prey Species
Intensive use of remote cameras represented a key methodology utilized in this
assessment. The cameras were deployed to obtain definitive evidence of presence,
general distribution and estimates of relative abundance for both tigers and their prey
species across the study area. In section 3.4.1 a theoretical and technical background
on use of remote cameras for Sumatran tiger monitoring is provided. A description of
the specific remote camera methodology employed in this assessment forms the basis
of the subsequent section 3.4.2.
3.4.1 Theoretical and Technical Introduction
Since their development in the early 1980s automatically-activated remote
cameras (camera traps) have been an important tool for monitoring rare, cryptic
species in a wide range of environments. Examples of such studies include the
detection of scavengers at deer carcasses (Cutler & Swann 1999), estimation of
grizzly-bear population size (Mace et al. 1994), activity patterns of Indonesian
rainforest mammals (Griffiths & van Schaik 1993) and the characterisation of tiger
populations in India (Karanth 1995, Karanth & Nichols 1998, 2000), and
Indonesia (Franklin et al. 1999, Franklin 2002).
Remote camera monitoring has proved particularly useful in the dense tropical
forests of southeast Asia, where field conditions are inhospitable to the
researcher and limit the applicability of many other techniques. The majority of
wildlife species in tropical forests are characteristically sensitive to the presence
of humans, thus making direct observation difficult. This is further compounded
by dense vegetation, which can reduce line-of-sight visibility to between 5 and 20
metres. Remote cameras, on the other hand, are easily placed and hidden in the
field, and most animals are oblivious, or rapidly adapt, to their presence. Remote
cameras do not suffer from the same constraints as human observers, and the
extended periods over which they can monitor in the field is very appropriate
under conditions where animal encounter rates are so low. Evidence for the
relative success of remote camera trapping of wildlife in tropical rainforests is
provided by many anecdotal examples where species have only ever been
recorded in this way, including the Sumatran rhinoceros (Dicerrorhinus
sumatrensis) in Way Kambas National Park (Siswomartono et al. 1996, by the
Sumatran Tiger Conservation Program).
Remote camera monitoring has also been applied to tigers in order to assess
population size and various aspects of the species’ ecology (Griffiths & van
Schaik 1993b, Griffiths 1994, Karanth & Nichols 1998, 2000, Franklin et al.
1999a, Franklin 2002). The unique and highly contrasting stripe pattern found on
the tiger’s flanks, legs, tail and head facilitates the distinguishing of individuals
(Schaller 1967, McDougal 1977, Franklin et al. 1999b). Based on this, providing
that clear and undistorted photographs are obtained, remote cameras enable the
identification of tiger individuals (Karanth 1995) on condition that a systematic
and careful approach to photographic comparison is employed.
Considerable effort has been focused on the need to develop a robust statistical
framework for remote camera monitoring, which is based on sampling of tiger
populations as opposed to direct census of individuals. Approaches have
included attempts to identify relationships between the number of camera days
required to photographically capture a tiger, with independent estimates of the
tiger’s density (Carbone et al. 2001 Jennelle et al. 2002), and the use of the
capture-mark-recapture models (Seber 1982) to estimate population size and
density (Karanth & Nichols 2000, Franklin 2002).
Sumatran Tiger Conservation Program Pg 23/68