The Tapanuli Orangutan (Pongo tapanuliensis) is the most threatened great ape species in the world. It is restricted to an area of about 1,000 km2 of upland forest where fewer than 800 animals survive in three declining subpopulations. Through a historical ecology approach involving analysis of newspaper, journals, books and museum records from the early 1800s to 2009, we demonstrate that historically Pongo tapanuliensis inhabited a much larger area, and across a much wider range of habitat types than now. Its current Extent of Occurrence is between 2.5% and 5.0% of the historical range in the 1890s and 1940s respectively. A combination of historical fragmentation of forest habitats, mostly for small-scale agriculture, and unsustainable hunting likely drove various populations to the south, east and west of the current population to extinction. This happened prior to the industrial-scale forest conversion that started in the 1970s. Our findings indicate how sensitive P. tapanuliensis is to the combined effects of habitat fragmentation and unsustainable take-off rates. Saving this species will require prevention of any further fragmentation and killings or other removal of animals from the remaining population. Without concerted action to achieve this, the remaining populations of P. tapanuliensis are doomed to become extinct within several orangutan generations.

中文翻译：

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Tapanuli猩猩的历史范围及其衰退的动因

Tapanuli猩猩（Pongo tapanuliensis）是世界上受威胁最大的大猿物种。它被限制在大约1000平方公里的山地森林面积中，其中三个下降的亚种群中只有不到800只动物存活。通过对包括1800年代初期到2009年的报纸，期刊，书籍和博物馆记录进行分析的历史生态学方法，我们证明了历史上的Pongo tapanuliensis居住的面积比现在大得多，而且栖息地类型也更广泛。目前的发生率分别是1890年代和1940年代历史范围的2.5％和5.0％。主要用于小型农业的森林栖息地的历史碎片化和不可持续的狩猎相结合，可能使目前种群的南部，东部和西部的各种种群灭绝。这是在1970年代开始工业规模的森林转换之前发生的。我们的发现表明，塔氏疟原虫对生境破碎化和不可持续起飞率的综合影响有多敏感。保存该物种将需要防止进一步的破碎和杀死或从剩余种群中其他移走动物。如果没有共同的行动来实现这一目标，那么塔帕努里斯疟原虫的其余种群注定要在几只猩猩世代内灭绝。保存该物种将需要防止进一步的破碎和杀死或从剩余种群中其他移走动物。如果没有共同的行动来实现这一目标，那么塔帕努里斯疟原虫的其余种群注定要在几只猩猩世代内灭绝。保存该物种将需要防止进一步的破碎和杀死或从剩余种群中其他移走动物。如果没有共同的行动来实现这一目标，那么塔帕努里斯疟原虫的其余种群注定要在几只猩猩世代内灭绝。