Biology Reference
In-Depth Information
plots has likely allowed them to survive and flourish while other fauna may not.
Analogously, urban populations of Hanuman langurs (
Semnopithecus entellus
) in
Jodhpur, India (i.e., another highly synanthropic primate) have survived serious
droughts while other local wildlife not as well adjusted to living near humans,
succumbed to the severe conditions (Waite
et al
.,
2007
). Overall, altered habi-
tat with exposed forest edges combined with stable food resources from human
activity may draw long-tailed macaques to human settlements, which then can
promote expansion of their population in an exotic environment.
Kabeana and West Papua provide an interesting contrast to Mauritius and
Ngeaur, as there the long-tailed macaques have not become as serious a prob-
lem. The West Papua macaque population growth is slower than in Mauritius
and Palau. The monkeys have been there for 30-100 years, but their population
has not expanded much. In fact, the population consists of only six groups of
~10 macaques each, yielding a total of 60-70 monkeys (Kemp and Burnett,
2003
,
2007
). Moreover, although Kemp and Burnett (
2003
,
2007
) flaws in their
research have argued that the macaques on Paua are negatively affecting birds
and reptiles in the Jayapura region, flaws in their research design make their
conclusions suspect. The researchers compared macaque-inhabited to non-
macaque-inhabited forest plots, but the macaque plots were all closer to human
settlements, while the non-macaque plots were around two to three times far-
ther from the nearest settlements. Consequently, it is just as likely that the
lower native bird and reptile numbers were due to closer proximity to humans
and their land alteration, than any direct influence by the macaques. Future
studies with better controls will be needed to resolve these ambiguities.
On Kabaena the macaques range over only 25 percent of the island. No ser-
ious invasion has been documented, the potential for conflict with native wild-
life has only been speculated, and they range over only ~25 percent of the island
(Froehlich
et al
.,
2003
). Like Papua, Kabaena does not have a highly disturbed
ecosystem. It therefore appears possible that on islands with less ecological dis-
turbance by humans, and with less provisioning by people, macaques may per-
sist, but do not extensively proliferate along the human-made edges across the
island. Of course, it is possible that a “macaque invasion” could occur if human
activity exposes too many forest edges and makes available food resources for
these animals to exploit. Moreover, the long history of macaques on Kabaena,
suggests an ecological expansion is not inevitable following release and that
long-tailed macaques can and do reach an equilibrium with their colonized
environment if not given too many advantages by human-altered habitat and
food resources.
Papua provides another example of introduced macaques not expanding in
an uncontrolled fashion. Macaques have been on Papua as long or longer than
they have been on Palau, but have not expanded to the same degree. Why?
