Na Hang Nature Reserve, Tat Ke Sector - Frontier-publications.co.uk

Na Hang Nature Reserve, Tat Ke Sector 1997
Two of these species (the Asiatic Black Bear and the Pig-tailed Macque) are regarded
as more heavily threatened within Vietnam than internationally, and are placed in
higher threat categories in the RDB (1992) than in the IUCN list (Groombridge,
1993). Another of the mammals, the Barking Deer (Muntiacus muntjak) is not
internationally threatened, but is regarded as 'Vulnerable' in the Red Data Book of
Vietnam (RDB, 1992).
11.4 Discussion
In comparison with the earlier survey in Ban Bung (Hill and Kemp, 1996), few
mammals were observed in the Tat Ke sector. This is due to a combination of factors:
undoubtedly, the presence on the earlier expedition of a skilled Vietnamese
mammalogist (Dr Dang Ngoc Can), and knowledgeable local guides, increased the
success of the first mammal survey. In addition, seasonal changes in the behaviour of
mammals may have influenced the possibility of observing certain species
(particularly the Tonkin Snub-nosed Monkey). However, one important factor must be
the level of human disturbance in the Tat Ke sector of the reserve, when compared to
the relatively undisturbed Ban Bung sector. Throughout the northern sector, clearance
for agricultural purposes fragmented the remaining forests and their mammal
populations. In addition, hunting pressure appears more intense in Tat Ke, affecting
populations of species which are preferentially hunted by man, for example, Wild
Boar (Sus scrofa) and Barking Deer (Muntiacus muntjak).
Four of the species recorded (all of them bats) were previously unrecorded in the
reserve, bringing the reserve total to 60 mammal species (and the total for the Na
Hang district to 83). One of the new bats, Murina sp., was a juvenile collected by a
local farmer on a banana plant, the others were collected in the course of bat-netting at
cave roosting sites.
This information, combined with that of the survey in Ban Bung sector (Hill and
Kemp, 1996), has added considerably to previous work on bats in the region.
Collating all previous survey data from the reserve, Na Hang contains at least 24
species of bats.Since new species were still being added during this survey, it is likely
that further species exist in the reserve. The combination of limestone geology and
good forest cover found at Na Hang are unique in Tuyen Quang province, suggesting
that this may be an site of regional or national importance for bat conservation.
The Tonkin Snub-nosed Monkey, Pygathrix avunculus was not observed during the
expedition, despite an extended satellite camp (of ten days duration) at a hide in
montane forest overlooking an area of undisturbed forest, where the monkeys had
been seen by a previous visiting group. Local people suggested that sightings of the
monkey were more frequent in the winter dry season, when the low availability of
water and scarcity of fruiting trees concentrated the population into certain restricted
areas. In contrast, during the summer wet season, food supplies are abundant and the
troops fragment to breed (Nguyen Kiem Son, pers. comm.).
Frontier-Vietnam Environment Research Report 9 42