The Sulawesi crested black macaque Macaca nigra is a Critically Endangered primate found naturally only on the northern peninsula of Sulawesi, Indonesia. The species has undergone an apparent decline of > 80%, attributed to habitat loss and hunting, since the first surveys were undertaken in the 1970s. The IUCN Red List assessment excludes an introduced population on the island of Bacan in the North Maluku archipelago.
Black macaques have been reported from Bacan, c. 300 km from North Sulawesi, since the mid 1800s. Although there has been speculation about the origin of this population, it has generally been concluded, based on morphology, that this macaque species is M. nigra (American Journal of Primatology, 15, 487–493). A survey in 1994 estimated a density of 170 individuals per km2 in Gunung Sibela Nature Reserve and 133 km−2 in unprotected logged forest near the village of Wayamiga (American Journal of Primatology, 44, 89–106).
We visited Bacan in February 2013 to assess the current status of the population and identify potential threats to its persistence. We conducted 18 reconnaissance walks (a total of 80 km) in the forests of the central portion of the island, including Gunung Sibela Nature Reserve. Our surveys predominantly sampled secondary forest interspersed with crops (coconut, cocoa, banana and vegetables), and primary forest (often at higher altitude). We recorded frequent signs of logging and clearance for crop production, although it was difficult to establish the legality of such activities as the boundaries between village land, protected forest and protected areas were unclear. We also interviewed 200 people from five nearby villages to quantify their use of forest resources and their attitudes towards the macaque and its habitat.
We encountered macaques on all but two reconnaissance walks, with an overall group encounter rate of 3.5 km−2. Although our methods are not directly comparable to those of surveys in the 1990s, this rate is lower than that previously reported for Bacan (6.8 km−2) but higher than that for North Sulawesi (2.7 km−2). The majority of encounters were visual and the macaques exhibit those morphological traits considered diagnostic for M. nigra, including the crest of hair and pink heart-shaped bottom (reports with photographs are available at www.selamatkanyaki.com).
Most people interviewed did not consume macaques (93%), although we observed that young macaques were kept as pets in three villages. The majority of people interviewed demonstrated positive attitudes towards forests and the macaques despite reporting that the species frequently raids their crops and that lethal traps are sometimes set for the macaques. These findings are in contrast to those for Sulawesi, where macaques are a favoured bushmeat species.
Our findings are limited by the briefness of our visit but indicate that a substantial population of M. nigra persists in central Bacan. If this situation is similar in northern and southern Bacan, as appears to have been the case in the 1990s, then the population of M. nigra on Bacan probably exceeds that in its native range. The Bacan population also appears to be less directly threatened than in Sulawesi. We recommend monitoring of the Bacan population to establish the impacts of any threats and to investigate any potential genetic effects of the presumably small number of founders.
The case of M. nigra on Bacan is unusual: a species that is Critically Endangered in its native range appears to have a much larger, potentially less threatened population hundreds of kilometres away as the result of an undocumented introduction. The role of this population for the conservation of the species warrants careful consideration, and the species' abundance, ecological impact and genetic status on the island requires further research.
The Bacan expedition was undertaken by Selamatkan Yaki, an initiative dedicated to the conservation of M. nigra and its habitat, and was funded by the North of England Zoological Society–Chester Zoo, with additional support from the Whitley Wildlife Conservation Trust and Taronga Conservation Society Australia.
