Ecoregional Assessment of Biological Diversity in East Kalimantan

East Kalimantan Ecoregional Assessment: Chapter 1 – Background & Analysis Process
For example, Mangrove forests are generally transitional between terrestrial and
marine/brackish environments and their ecology is greatly influenced by the substrate of
sediment build up, rather than the underlying RePPProT landforms. There is, however, a
noted area of exception to this, namely, the Mangroves that grow directly on top of limestone
substrate in a small bay and its enclosed island on the northern coastline of the Sangkulirang
peninsula. Such unique areas, identified to the ECA team by experts, were automatically
included in the proposed portfolio as deserving of further conservation attention since it is
likely they also harbor unusual plants and/or animals as well.
To capture more of the landscape heterogeneity, the portfolio of conservation sites selected
will also contain representatives of all possible combinations of target ecological system
types – as well as the important RePPProT land system types. Most importantly, though, only
the target system- and not the RePPProT types- will be the initial basis of assembling the
portfolio of sites. The landscape unit will be used as a secondary filter for checking
representation of each target.
At the completion of the assembly phase, RePPProT types that have not been represented
will be sought and added to the portfolio where possible. This approach is very similar to the
TNC-US methodology of employing Ecological Land Units analysis to incorporate either in
the selection of ecoregional portfolios up front, or, as we did, to use the information to crosscheck
the selected portfolio for under-represented heterogeneity of these geomorphic factors.
It can be argued that either case insures that more subtle landscape variations, which plant
and animal species often key on, are incorporated into the recommended conservation
portfolio.
Fine-Filter Targets: Five Important Animal Species
The presence of five important wildlife species (Sun Bear, Orangutan, Bornean Gibbon,
Mahakam River Dolphin, and Proboscis Monkey) (see Figure G) within potential portfolio
sites in each stratigraphic unit was also assessed. These species were selected for one or
more of the following reasons:
- large body size or vocally distinct, thereby easily detectable in the field (such as
Gibbons)
- wide-ranging habits spanning several of our target forest system types
- presence at the top of their respective food webs
- natural history information which suggests that the species require unfragmented
blocks of habitat, and therefore their presence in substantial numbers or in stable
family groupings becomes a good indicator of viable forest types.
Clouded Leopard (Neofelis nebulosa) was initially considered in this assessment due to its
globally-rare status, but was dropped when the ECA team concluded that virtually no recent,
reliable occurrence or ecological information was available for this species. It is hoped that
by capturing the full array of target ecological system types in the ECA portfolio, particularly
the Upper Montane and Cloud Forest types, essential habitat for this and other high profile
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