The conservation of tigers and other wildlife in oil palm plantations

CONCLUSIONS
Oil palm is a very poor habitat for mammals
The value of oil palm crop as wildlife habitat
The results of the study show that the oil palm crop is a very poor habitat for most
mammals. Ninety-five percent of mammal species recorded in the area demonstrated a
preference for non-oil palm habitats, 55% were never recorded in oil palm and only 10%
showed any ability to survive within the oil palm crop on a long- term basis. Intolerance
towards oil palm was strongest in the most endangered species (see p.55 for a summary).
Tolerant species
The only mammal species other than rodents
able to survive within oil palm over significant
periods of time were wild pig, bearded pig,
leopard cats and common palm civets, all of
which appeared fairly successful. None of these
are considered high value for conservation,
although leopard cats are protected under
Indonesian law and also restricted for trade under
CITES, and bearded pigs are a poorly understood
species with some research interest. The pattern
of high biomass, low diversity seen in the oil palm mammals is likely to be repeated for
other taxonomic groups. Several snake species were common in oil palm for example,
as were some amphibians, and a small number of bird species also occur regularly;
however, species diversity is almost certainly poor in all cases. These species are likely
to survive by obtaining direct and indirect benefits from the crop that outweigh the
disadvantages of living in the crop. Both pig species are generalists that are known to
eat the high energy oil palm fruit and also young palms, although high levels of rooting
evidence within the crop suggest that they also feed on alternative food sources such
as invertebrates and roots. Pigs appear to use the unplanted areas bordering rivers
and/or outside the crop for cover. Palm civets are also generalist omnivores and
probably survive on a mixture of fruit, insects, amphibians and occasional rodents.
They were almost always spotted sheltering in the palm canopy. Leopard cats on the
other hand probably survive almost entirely on the high densities of the small number
of rodent, amphibian and reptile species that occur in oil palm. Hunting these species
would not require dense cover and leopard cats are small enough to shelter in the
canopy or low-lying leguminous foliage if they need to hide.
Species displaying limited tolerance
Survival for other species is probably limited
within the oil palm by both the lack of cover and
the lack of plant diversity within the crop. Oil
palm plantations are monocultures, with trees
planted at exactly 9 metres apart to maximise
canopy cover. Beneath the mature canopy light
levels are low. Low, leguminous ground cover is
often encouraged and ferns are occasionally left
on palm trunks, but beyond that there is almost
no vegetative cover leaving a very open habitat,
with little heterogeneity. In these circumstances most animal species would find
survival very difficult because of vulnerability to predators (including humans), lack of
cover for hunting (e.g. tigers, which rely on ambush hunting techniques), difficulties
in moving through the habitat (primates in particular would find the dense, spiny
canopy a barrier) or lack of food resources (whilst oil palm and a few associated
species are abundant, little else is). Species showing limited tolerance to oil palm
included sun bears, deer species and several primates, all of which were recorded very
Wildlife conservation in oil palm plantations 43