Ecoregional Assessment of Biological Diversity in East Kalimantan

East Kalimantan Ecoregional Assessment: Chapter 2 – Target Ecological Systems
Occurrence Unit Determination
As in other discrete ecological system types, significant Karst Forests were identified first
using LandSat imagery to determine their location within the province. The ECA team then
consulted with individual experts and literature sources, followed by ground surveys,
sometimes quite detailed, for priority sites proposed for inclusion in the portfolio.
A Karst Forest occurrence was defined as an individual patch that is not physically connected
to other Karst Forest patches. In the case of several patches (e.g., in the Sanggata and Pasir
regions) which are divided by primary river system, each dissected part was regarded as a
separate occurrence since hydrology does not functionally link the patches as would be the
case for Freshwater Swamp and Peat Swamp forests.
Portfolio Design
The overall goal for Lowland Limestone Forest in the East Kalimantan Portfolio was 60%,
which was achieved.
Results
The overall goal was achieved with just over sixty percent (60.3%) of the known occurrences
selected for the portfolio. These were distributed within the stratigraphic units as follows:
SU-1, 89.8%; SU-2, 58.7%; SU-3, 64.8% and SU-4, 59.4%).
Twenty-two separate occurrences were included in the portfolio. In SU-1, there are only a
few small occurrences, but the three largest of these, in the best condition, were selected.
These account for 89.8% of those present in this unit, but, because they are all small, this
does not unduly bias the achievement of the 60% goal for all of East Kalimantan.
In SU-2, many of the Lowland Limestone Forest occurrences in the middle precipitation zone
(2000 – 3000 mm) were badly damaged by repeat fires in 1997/1998. These damaged
occurrences were not included in the portfolio. This decision results in an underrepresentation
of this forest type in the SU-2, especially in the median precipitation zone,
where only a single element occurrence was selected, representing 10.7% of the available
occurrences. In stratigraphic unit 2, more occurrences were selected from the lower
precipitation zone (72.2%). Most of these are on the Sangkulirang-Mangkalihat Peninsula
and are very close in annual precipitation values to the damaged elements and, as such,
probably experience similar climate regimes. Therefore, it was felt that these occurrences
would adequately represent this system type in SU-2. These selected occurrences also
overlap with the Important Bird Area identified in this unit.
In stratigraphic unit 3, the occurrences were somewhat evenly distributed across the east to
west precipitation gradient. Most had a Good or Very Good viability index - so each of the
precipitation zones was well represented. One poor viability occurrence was included in the
portfolio because it was located within Kutai National Park. Other occurrences were selected
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