Ecoregional Assessment of Biological Diversity in East Kalimantan

East Kalimantan Ecoregional Assessment: Chapter 2 – Target Ecological Systems
The Cloud Forest is a unique and eerie place. Short, gnarled trees dripping with moss,
frequently Sphagnum sp., as well as liverworts and filmy ferns abound. And, amongst these
strange plants are a wide variety of orchids, both terrestrial and aerial. The silence of this
upper altitude habitat is pierced with a range of calls from cryptic ground-dwelling birds not
encountered in the lower montane forests.
These rainforests are characterized by an absence of cauliflory, very few bole climbers and
large woody climbers, and frequent or abundant vascular and non-vascular epiphytes
(Whitmore 1985). Soils tend to be more acidic in these forests. As a consequence,
decomposers are less abundant and peat soils tend to accumulate over time. The cloud forests
on the summits receive water only from atmospheric moisture (clouds) so their soils are
particularly nutrient deficient (Burnham 1984). Several species of plants (e.g., rhododendrons
and pitcher plants) have evolved complex strategies to overcome the lack of soil nutrients.
Upper Montane Rainforest/Cloud Forests are of great biological interest, not only because
they represent Pleistocene refuges, but also because they are centers of speciation and
endemism, particularly for smaller species of mammals, cryptic ground birds, amphibians
and invertebrates. These mountainous areas have evolved a unique flora and fauna that is
only partly shared with the Lower Montane/ Middle Montane Rainforests. Plants in the
Upper Montane forests show a high level of endemism. For example, Smith (1970) reports
that 40% of the plants found in the submontane parts of Mt. Kinabalu in the Malaysian State
of Sabah, are found only on that particular mountain.
Upper montane flora found in the Upper Montane / Cloud Forests, is derived from both the
Asian and Australasian regions. Trees in these upper montane zones include families from
the temperate latitudes (Aceraceae, Araucariaceae, Clethracea, Ericaceae, Fagaceae,
Lauraceae, Myrtaceae, Podocarpaceae, Symplocaceae, and Theaceae) (Whitmore 1984).
It should be noted that few of the high mountain areas of the East Kalimantan province have
been surveyed. WWF and Birdlife International list three Upper Montane areas in East
Kalimantan as Important Bird Areas; these are Kayan Mentarang, Ulu Telen, and Long
Bangun.
Surveys of small ground mammals and bats along altitudinal gradients in Indonesia show that
species richness declines with increasingly high altitudes and is lowest in the Upper Montane
Rainforests and Cloud Forests (Kitchener and Yani 1996, 1988 – Flores Island; and
Kitchener et al. 1997- Irian Jaya). However, in Lore Lindu National Park in the neighboring
island of Sulawesi, there was no clear trend for species diversity of small ground mammals to
decline with increasing altitude – although there was a dramatic decline in diversity of bats
above 1500 meters (Maryanto and Yani 2002). Endemic rodents in many places in Indonesia
are most commonly found in Upper Montane Rainforests/Cloud Forests (Musser 1977;
Kitchener et al. 1991a,b,c, Kitchener and Yani 1996; Kitchener et al. 1997; Kitchener and
Yani 1988; and Musser 1981).
Bird diversity in the tropics is generally highest in lowland forest areas and decreases with
altitude (Coates and Bishop 1997; MacKinnon and Phillips 1993). However, in Lore Lindu
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