Biology Reference
In-Depth Information
experienced significant problems from many exotic species, have had high lev-
els of habitat destruction, and have easily assessable crops and human resources
(Porrier and Smith,
1974
; Lorence and Sussman,
1986
; Wheatley, Chapter 10;
Sussman, Chapter 8). The number of exotic species present on these islands
makes it difficult to isolate the specific effects of long-tailed macaques.
Mauritius has been extensively modified from human activities (Lorence and
Sussman,
1986
), and habitat destruction has been very intense in Ngeaur, where
there was an intensive three-month bombing during the American invasion in
World War II, which obliterated the island's forest regions (Poirier and Smith,
1974
). Both islands also have reports of extensive crop raiding and dependence
by macaques on human farming (Mungroo and Tezoo,
1999
; Wheatley
et al
.,
2002
), and Dutch settlers may have abandoned Mauritius because of heavy raid-
ing by macaques (Sussman and Tattersall,
1981
).
Another clue that specific conditions led to macaque colonization comes from
the isolation of macaques on Ngeaur Island in Palau. Although pet macaques
have been sold to people on other islands in Palau, there have been no suc-
cessful colonization events on these islands even though some of these pets
have escaped (Wheatley
et al
.,
1999
,
2002
). This seems to indicate that rather
than just being a solely intrinsic ability of long-tailed macaques to easily col-
onize an island and exploit new niches there are also certain ecological and/
or anthropogenic conditions that facilitate these so-called macaque invasions.
Perhaps human impact is the key for allowing successful macaque colonization
on an island.
It appears possible that a few key ingredients play a significant role in facili-
tating exploitation of new environments. First, on Mauritius and Ngeaur there
was severe environmental alterations and damage from human activity dur-
ing the development of their macaque population. Given this important factor
occurred on both islands, it is possible that anthropogenic habitat disturbance
provides niches suitable for macaques. For example, forest edges and new
food patches that the macaques can easily exploit with little or no competi-
tion from the local fauna may become available following land development
by humans. Moreover, long-tailed macaques have been documented to cope
well with severe environmental damage (e.g., fire destruction in Kalimantan)
(Berenstain,
1986
). This may give long-tailed macaques an advantage in sto-
chastic environments compared to local fauna, which are adapted to the predis-
turbed stable environment.
A high level of sustenance from human agriculture and human-derived food
sources may be of equal importance in supporting macaque colonization. Human
resources were consistently available on both Mauritius and Palau during the
population expansion of their macaques. Therefore, it seems likely that the
long-tailed macaque's ability to live in human settlements or near agricultural
