Biology Reference
In-Depth Information
commodities such as sugarcane, rubber, coffee, corn, cassava, etc., has been
established. Moreover, hunting and trade of live wildlife and its products
are prevalent. These threats will continue to increase with the construction
of roads and bridges connecting Laos and neighboring countries. A detailed
assessment will be necessary to evaluate the impact of these human activities
on macaque populations.
Discussion
Distribution of long-tailed and rhesus macaques
in southern Laos
The population and distribution of long-tailed macaques in southern Laos
was determined using the data obtained in the present and previous studies
(Duckworth
et al
.,
1999
). Long-tailed macaques were found to be distributed in
southern-most Laos, 15.2˚N or lower, in the forests of Attapeu and Champasak
Provinces. In Attapeu, they distributed in the Xay Phou Louang range and
probably in forests south of the Xe Xou River, while in Champasak they are
found in the Bolaven Plateau, Xe Pian NPA, and in the region west of the
Mekong River. The total national population of Laotian long-tailed macaques
was estimated to be in the range of 420-4,200 individuals.
Rhesus macaques were found distributed in almost all areas of Laos (>14˚N).
The southern limit of rhesus macaque distribution has not yet been determined
because studies have yet to be completed in the forested area on the eastern
bank of the Mekong River (i.e., Xe Pian NPA), areas along the Xe Khong River,
and the forested area in northeastern Cambodia (i.e., Rattanakiri and Stoeng
Treng Provinces). In central Laos (i.e., middle latitude), rhesus macaques were
found only in the low-profile mountainous and plain areas. That is, they pre-
ferred nonevergreen secondary or disturbed forests. They did not appear to
have adapted to the dry hilly forests in southern-most Laos, to which northern
pig-tailed macaques adapted, which may be why rhesus macaques were not
distributed to the western bank of the Mekong River continuous to northeast
Thailand.
Sympatric relationship between long-tailed and rhesus macaques
Long-tailed and rhesus macaques are generally allopatrically distributed
(Fooden,
1982
) to areas of lower and higher latitudes, respectively. This pat-
tern of separation may occur because the two species are closely related and
