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Kinabalu has a long been known for its biological diversity and high levels of
endemism. Kinabalu possesses one of world’s richest orchid floras with more than
half (746) of the estimated 1,400 species for Borneo. Another frequently quoted
figure is that for the ferns. There are over 600 species on Kinabalu (more than
in the whole African continent, which has about 500 species), 50 of which are
found nowhere else.
Today Kinabalu is studied more than other mountain in Borneo, so some species
that are presently though to be endemic to the mountain may yet be found
elsewhere as other Borneo mountains are exploded further.
Why should the mountain have developed such an incredible array of plant life?
The answers lie in its distant past as well as in its more recent evolution.
First and foremost, Kinabalu is situated in the one of the richest plant regions
of the world, covering a wide climatic range from near sea level to freezing
ground conditions below the summit. The jagged terrain and the diversity of
rocks and soils have combined with the instability caused by periods of
glaciations, and other catastrophic events such El Nino droughts, to produce
ideal conditions for evolution and speciation to take place. Evolution is driven
by change. Because they are immobile, plants cannot escape changing conditions
as easily as animals so they must adapt or die, and in adapting have evolved
many endemic species.
The diversity is greatest in the lowland forests, but most of Kinabalu’s
endemics are found in the mountain forests, particularly on ultramafic soils.
Kinabalu is the richest place in the world for the tropical pitcher plants
Nepenthes. Ten out of the approximately 36 species in Borneo are found on this
single mountain, where they reach an unparalleled level of spectacular elegance.
Five, restricted to the ultramafic soils, are found nowhere else.
Periods of small scale extinction have also occurred in cases where plants have
been limited to restricted areas, particularly after castastrophic events. Some
studies have recorded about 22% local extinction within 10 years and
observations after the most recent 1998 El Nino drought suggest that as many as
50% of the epiphytes were killed off on certain parts of the mountain. On the
other hand many animals can move away from adverse conditions and endemism is
much less, at least among the larger animals. Nevertheless some groups,
particularly among the insects, have developed a remarkable degree of diversity.
Of the more than 900 butterflies known from Borneo, over 600 (two-thirds) are
found in the Kinabalu Park, making it a hotspot of butterfly diversity not only
in Borneo but in the whole of South-east Asia. Butterflies are mainly creatures
of the lowlands, however, and while diversity is high, endemism is low.
Moths are even more diverse than the butterflies, with well over 1,000 species
on Kinabalu (more than 3,400 are estimated for the whole of Borneo). In contrast
to the butterflies, moths increase in both numbers and diversity higher up the
mountain, and many species are endemic. Around 2,000 metres (6,500 feet) on the
Kinabalu, endemism reaches about 50%. Above this height, the level of diversity
drops and only four species are recorded about 3,000 metres (10,000 feet).
Mammals and birds which can move easily over large areas and are most common in
lowland habitats are less likely to develop endemism. Though several bird
species were once though to be endemic to Kinabalu, it is now known that they
all also occur on Sabah’s other two highest mountains, Tamboyukon and Trus Madi.
Of the mammals, only two, the Black Shrew (Suncus ater) and the Kinabalu Shrew (Crocidura
baluensis) are endemic to the mountain. However, the Black Shrew is known form
only a single specimen, collected at 1,700 metres (5,600 feet), and the Kinabalu
Shrew was, until very recently, regarded only as a form of the very wide spread
South-east Asian White-toothed Shrew (Crocidura fuliginosa). The opposite
situation prevails regarding the Kinabalu Ferret-badge (Melogale personata
eretti) which was thought to be endemic to Kinabalu and nearby Gunung Tamboyukon.
This animal is now recognized as only a sub-species of the ferret-badger that
occurs widely across South-east sway at the time. Similarly, the well-known
Kinabalu Rat that occurs around the mountain huts at Laban Rata and has been
recorded as high as 3,100 metres (10,200 feet), was once though to be endemic,
but is now regarded only as a high altitude form of the common lowland
Long-tailed Giant Rat (Leopoldamys sabanus). |
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