‘Oh hot “dam”! a new orangutan!’ – newly identified orangutan under threat science blog – mresbec wd gaster


Welcome to the party! Just last year, deep in Indonesia’s Batang Toru Forest, a new species of orangutan was discovered. However, with less than 800 individuals, the Tapanuli orangutan has immediately become the most endangered great ape. As if pressures from hunting and deforestation weren’t enough, the newest great ape’s isolated refuge is now facing imminent threat; a hydroelectric dam, expected to be complete by 2022 is set to destroy at least 8% of their habitat ( 1).

Introducing the Tapanuli orangutan, the latest member of our great family. electricity usage in the us The great ape family currently comprises 8 members; 2 species of Gorilla, Chimpanzees, Bonobos, Humans and now 3 species of Orangutan. The orangutan species include the Bornean orangutan ( Pongo pygmaeus ), the Sumatran orangutan ( Pongo abelii ) and recently identified, the Tapanuli orangutan ( Pongo tapanuliensis ), all 3 are currently listed on the IUCN red list as Critically Endangered ( 1, 2).

The Tapanuli, in common with the two other recognised species of orangutan, is under serious threat from the activities of man in the forest. Its habitat has been reduced by destruction of primary forest for the purposes of logging and agricultural development ( 1). The pattern of ‘development’ of virgin forest leads to fragmentation of the species range. Specifically, Tapanuli occupy 3 discrete areas in the Batang Toru region, referred to as the west block, the east block and a smaller fragment comprising the Lubuk Raya reserve ( 1). With such small numbers of individuals, a serious concern is the reduction of the gene pool and resultant inbreeding, which would seriously harm the long-term prospects of the species. It is imperative therefore that links between the 3 identified ranges are maintained, so as not to further isolate groups of the animals. gas pump icon These links must comprise corridors of forest through which the orangutan can safely pass. A complication here is the existence of roads in these areas which can facilitate activities such as illegal deforestation, illegal mining and hunting of the orangutan ( 3). A further threat on the horizon for the Tapanuli is a proposed hydroelectric dam ( 1). A map to show the 3 distinct regions within the Batang Toru ecosystem; West block, East block and Lubuk Raya

A hydroelectric dam is a manmade structure which uses the flow of water to generate electricity. The proposed dam will be built on the Batang Toru river, the largest water catchment in the area. The construction site of this dam is in an area of the forest which holds the highest density of Tapanuli orangutans. This dam is set to threaten at least 8% (96 km 2) of the orangutans habitat. bp gas prices For these tree dwellers, that rarely touch the ground, the absence of trees will prevent movement from one area to another. This will cause isolation of subpopulations. gas utility cost Construction of the dam and the associated power plant, roadways and electrical lines will permanently fragment the home of these orangutans. For a population with such a low number of individuals, construction of this dam may drive complete extinction of the Tapanuli orangutan ( 1, 4). Image of a hydroelectric dam

However, the orangutan may be more resilient than we originally feared ( 3). The existence of our new species at all is partly as a result of the isolation of a subpopulation in the south of the range. Natural events such as the super eruption of Toba 73,000 years ago lead to massive deforestation in the area, which may have contributed to a divergence in the 2 contemporary species ( 1). However, the relentless advance of homo sapiens into the forest is a much more serious threat and there is urgent work to be done if the Tapanuli is not to become extinct very shortly after its first description as a new species. t gastrobar el tenedor Pongo tapanuliensis

Secondly, cleared land around remaining fragments of forest should be restored as faunal corridors. Designations for these areas would have to be changed and a section of existing roadway would have to be closed. Sloan et al. point out that settlement and agriculture are sparse here and economic impact would therefore be minimal. Further, an alternative less damaging route for a roadway exists south of the west block. It is estimated that restoring only a few 100 hectares of the agroforest would suffice to enable movement of the orangutan between the east and west population blocks.

The final and most contentious recommendation is to cancel the hydroelectric power project which stands to remove or alter 8% of habitat by 2022 and confound all hopes of a link between the east and west blocks. Further the service roads necessary for the scheme would bring all the dangers already specified where opportunities for illegal activities would result from easier access.

Given the assumed difficulty of turning the Indonesian government through 180 degrees in respect of its plans for the dam it may be that a more pragmatic approach might be adopted. If, for example, independent funds could be raised to support the project, conditional on the Indonesian government accepting the guardianship of these beautiful animals, the authorities would then have a stake in their protection.