Ecoregional Assessment of Biological Diversity in East Kalimantan

East Kalimantan Ecoregional Assessment: Chapter 2 – Target Ecological Systems
Portfolio Design
The goal for East Kalimantan is 50% of the areal extent of viable mangrove forests, including
100% of mangroves in Kutai National Park. Of the 656,000 hectares present in East
Kalimantan, we recommend conservation management of roughly 427,000, or 65% in the
Portfolio. The rationale for the higher percentage is that the rate of degradation of this forest
community is so rapid, that by the time of publication of this report, it is likely that a
significant amount of Mangrove has already been totally converted or further degraded to the
point it would not qualify under our “viability” criteria.
Appendix III presents the selected proportion of Mangroves in East Kalimantan and the
selected proportion of Mangrove Forest in the various precipitation zones. Mangroves are at
the interface of the land and sea, and as such are not greatly impacted by the RePPProT
systems that abut them. The exception is a small set of occurrences that grow almost directly
from limestone substrate on the central northern part of the Sangkulirang Peninsula (Ben
Jarvis and PT Daisy report). This was an example of a report of a “unique” occurrence that
led to its inclusion in the portfolio.
Results
Seven major occurrences were selected for the portfolio. The extent of mangrove varied
greatly in each stratigraphic unit, with most in stratigraphic unit 1. However, mangroves were
most damaged in stratigraphic unit 3 where the average occurrence had a viability ranking of
Poor. In stratigraphic unit 3, mangrove forests of low viability were included in the portfolio
because they were a functional necessity of the targeted Major River – the Mahakam. While
it is recognized that the majority of this occurrence at the Delta Mahakam site is degraded or
converted to tambak already, it will be our recommendation to the Natural Resources Dept.
of BAPPEDA in that area to pursue restoration of this community type. If the natural riverine
processes are protected upstream, and functioning as planned, then restoration should be
fairly successful if there is the motivation of the local government to do so with the
participation and compliance of the local communities. As more is learned of the protective
nature of mangrove forests to coastal communities, there is a growing appreciation of the
services provided by this natural soil stabilizing and water filtration agent.
Occurrences that were added to those of the target Major River were based on association
with that rivers delta and to provide coastal continuity of mangroves. These occurrences
could then act as both ecological stepping stones for the mangrove fauna, in particular the
mangrove dependent assemblage of birds, and at the same time assist in consolidating the
greatest extent of coastline.
Stratigraphic Unit 1 - The mangrove forest patches at the terminus of the Sebuku/
Sembakung river system are the primary representatives of this forest system type in the first
stratigraphic unit. Total areal extent amounts to roughly 194,144 hectares.
Stratigraphic Unit 2 – Three Major Rivers occur in this Unit (Kelai/ Berau, Segah and
Bungalung). Each of these has an extensive mangrove delta. However, the mangrove forests
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