Ecoregional Assessment of Biological Diversity in East Kalimantan

East Kalimantan Ecoregional Assessment: Chapter 2 – Target Ecological Systems
F. Lowland Limestone (Karst) Forests
Description
As in most areas of the world where this biologically diverse geologic formation is found,
there is a wide range of plant communities found on limestone substrates in Kalimantan. In
addition to the Lowland Limestone Rainforest target, MacKinnon et al. (1996) identifies
Lowland Scree Forest, Lowland Limestone Cliff Communities, Lower Montane Lowland
Limestone Rainforest and Upper Montane Lowland Limestone Rainforest. In East
Kalimantan, only the first three types are found – both of the Montane Lowland Limestone
Rainforests are absent.
The Lowland Scree Forests and Lowland Limestone Cliff Communities are represented in
this assessment within our Lowland Rainforests ecological system. They are mainly found on
the RePPProT landsystem types GBJ (flat karst country with rolling hills) - which are
extensive in the northeastern part of the Sangulirang Peninsula in stratigraphic unit 2 -and
occasionally on the KPR type (rolling hills with highly fractured karst). These forests vary in
structure considerably from Lowland Limestone Rainforest. They are characterized by being
fairly open with massive emergents as opposed to the closed canopy typical of intact
Lowland Limestone Rainforest.
Lowland Limestone Rainforests form dense irregular forests on steep limestone country
where slopes are greater than 45 o . They are tall forests comprised mostly of dipterocarps,
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