The 82nd Annual Meeting of the American Association of Physical Anthropologists (2013)

Densities, distribution and detectability of a small nocturnal primate (Javan slow loris Nycticebus javanicus) in a montane rainforest


Nocturnal Primate Research Group, Oxford Brookes University

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Nocturnal mammals can be challenging to survey; for those that live in dense forests limited information is available on densities. The Javan slow loris N. javanicus confined to the island of Java, Indonesia has been classified as Critically Endangered on the basis of a high demand in the illegal pet trade and dramatic loss of forest. Still virtually nothing is known about their numbers in the wild. We aimed to report on the presence and distribution of Javan slow lorises in Mt Gede-Pangrango National Park, West Java and to present data on their densities and population size. We examine relationship between detectability and speed at which transects are walked, habitat, and moon phase. We provide density data using Distance from 23 transects walked for a total of 260 hours covering 93 km. Transects measured between 0.5 and 4.7 km, and were walked at speeds between 200-550 m / hr. Transects occurred mainly or exclusively in secondary forest, mainly or exclusively in primary forest or in a combination of both. Lorises were found at a density of 0.16/ km2, with an estimated population of 70 individuals, with a detectability of 0.57. Neither forest type, nor moon phase related to loris abundance, but walking speed did (F1,5=17.3, P=0.014) with numbers declining at a faster pace. The very low densities in this important protected area correspond with a conservation status of Critically Endangered for N. javanicus. Our methodological findings are of relevance to all those who survey nocturnal animals.

The Leverhulme Trust, The Little Fireface Project

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