The Rimba Raya Biodiversity Reserve REDD Project

GL3.2.2. Species with Large but ClumpedDistributionsSpecies with large but clumped distributions -­‐ 5% of the globalpopulation at the site;Project benefits for the Bornean orangutan (Pongo pygmaeus),endemic to Borneo, deserve special mention. Much of the land inthe Project Area remains undeveloped, providing an estimated44,000 ha of additional forest contiguous with TPNP to the westof the Project Area (OFI 2008). This represents 14% of forest inthe region of TPNP and adjacent areas (the ‘greater TPNPlandscape’), providing significant habitat for orangutans andother wildlife. A recent study on orangutans in TPNP and itsbuffer, which partly includes the Project Area, found residentorangutan populations averaging 1.9 orangutans per squarekilometer (Galdikas et al. unpublished report, cited in OFI 2008).More recent field surveys by OFI confirmed similar orangutandensities in the Project Area as a whole, and showed thatindividual orangutan home ranges cross the park boundary intothe Project Area. These data demonstrate the occurrence of oneor more inter-­‐connected orangutan population(s) in the greaterTPNP landscape, including Rimba Raya.The Bornean orangutan population of TPNP is estimated to bemore than 4,700 individuals (OFI 2008), or c. 9.8% of the totalestimated population of c. 48,000 for all of Borneo (Ancrenaz etal. 2008). Adjacent forests in the Project Area provide anadditional 44,000 hectares of suitable orangutan habitat,supporting an estimated 760 individuals. This augments theTPNP orangutan population by an additional 14%, and the globalpopulation by nearly 2%.It is expected that the project will greatly reduce deforestationrates over the coming years, primarily by preventing oil palmplantation development into the park buffer zone along thewestern bank of the Seruyan, and by limiting access to thenational park from the eastern border. This will have markedimpacts on the long-­‐term population status of the orangutan. A2008 analysis of past and future projected deforestation in theProject Area found that forest in the Project Area would becompletely deforested in 20 years and that of the park would losean estimated 147,000 hectares (60%) of its forest cover duringthis same period. By extrapolation, this simplified ‘withoutproject’ scenario suggests that the orangutan population in theProject Area would be reduced by more than one-­‐half and that ofthe greater TPNP orangutan population would be reduced by onethird, in the absence of project activities to mitigate these losses.Thus the Project Area itself contains nearly 2% of the globalpopulation and provides vital protection and support toguarantee long term persistence of a further 9.8% of the globalpopulation of this species.GL3.2.3. Globally Significant CongregationsGlobally significant congregations -­‐ 1% of the global populationseasonally at the site;N/A282