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Species diversity in the region is extremely high. Indonesia
is thought to support more species, with more endemic species, than any
other country in the world, closely followed by several others, including
Australia and China (Groombridge 2000). The tropical waters around the
Indo-Australasian archipelago are the world's centre of diversity for
a wide range of marine groups, including corals, coral reef fishes and
mangroves (Groombridge 2000). Rangelands in western parts of the region,
the Tibet plateau and Australia are particularly rich in lizards and snakes
adapted to arid conditions (Anderson 1963, Cogger 1992, Zhao and Adler
1993). Many of the rivers and freshwater lakes hold endemic species of
fish and aquatic invertebrates (Kottelat and Whitten 1996).
| New species in Viet Nam |
| Two large mammals previously unknown to science have been discovered
in one small area, the Vu Quang Nature Reserve in Truong Son, Viet
Nam. The Vu Quang ox (Pseudoryx nghetinensis) was first described
in 1993, followed a couple of years later by a giant muntjac deer
(Megamuntiacus vuquangensis) from the same area. The ox is
of particular interest because it does not appear to fit neatly in
any of the main bovid groups as currently recognized. It is now known
to occur in adjacent parts of Laos. Other new species have also been
found, including the world's smallest muntjac deer, the Truong Son
muntjac (Muntiacus truongsonensis). |
| Source: Dung and others 1993 |
The larger islands are home to a wide range of endemic
species while the continental areas often have high species richness together
with high rates of endemism. Such 'hot spots' can be identified at a range
of scales, from individual mountains to extensive hill ranges. The entire
Hindu Kush- Himalayan belt has as many as 25 000 plant species, comprising
10 per cent of the world's flora (Shengji 1998). A few such areas remain
relatively unknown: remarkably, even new large mammal species have recently
been described in Viet Nam and Laos (see box).
Biological resources have long been of subsistence importance, and have
been increasingly exploited for trade. At the global level, around three-quarters
of known or suspected species extinctions have occurred on isolated islands
(WCMC 1992), many of which were molluscs and birds from the Asia-Pacific
region. Some 1 469 vertebrate species in the region are currently considered
to be threatened with extinction (see bar chart above). Habitat loss is
the principal factor that fragments natural populations and increases
their risk of extinction but this often acts in synergy with other pressures
such as alien species and unsustainable harvesting (Eder 1996, NBSAP 2000,
NIES 1997).
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