Home ranges, spatial movements and patterns of habitat use were determined during a radio-tracking study on four male and six female Philippine tarsier Tarsius syrichta in Corella, Bohol, from early March to October 1999. This was the ®rst radio-tracking study of the Philippine tarsier that included both breeding adult males and females. Home ranges averaged 6.45 ha for males and 2.45 ha for females (MCP and Kernel 95%), allowing for a density of 16 male and 41 female tarsiers per 100 ha. The habitats are primarily located in secondary lowland rainforest in early to mid succession stage, but individual tarsiers readily traversed open grass areas to move between forest patches. However, the tarsiers avoided adjacent residential areas, clearings and agricultural plantation, even if the last two were found enclosed in homerange polygons. The home range of one male overlapped extensively with that of one female and to a lesser extent with a second female. Home ranges of males showed little overlap (2.71%) and the same was observed among the females (3.35%). Nightly travel distance averaged 1636 m for males and 1119 m for females. Individuals were observed to forage and sleep solitarily. The tarsiers form groups of one adult male and one or two adult females and their offspring.

Establishment of conservation priorities for primates is a particular concern in the island archipelagos of Southeast Asia, where rates of habitat destruction are among the highest in the world. Conservation programs require knowledge of taxonomic diversity to ensure success. The Philippine tarsier is a flagship species that promotes environmental awareness and a thriving ecotourism economy in the Philippines. However, assessment of its conservation status has been impeded by taxonomic uncertainty, a paucity of field studies, and a lack of vouchered specimens and genetic samples available for study in biodiversity repositories. Consequently, conservation priorities are unclear. In this study we use mitochondrial and nuclear DNA to empirically infer geographic partitioning of genetic variation and to identify evolutionarily distinct lineages for conservation action. The distribution of Philippine tarsier genetic diversity is neither congruent with expectations based on biogeographical patterns documented in other Philippine vertebrates, nor does it agree with the most recent Philippine tarsier taxonomic arrangement. We identify three principal evolutionary lineages that do not correspond to the currently recognized subspecies, highlight the discovery of a novel cryptic and range-restricted subcenter of genetic variation in an unanticipated part of the archipelago, and identify additional geographically structured genetic variation that should be the focus of future studies and conservation action. Conservation of this flagship species necessitates establishment of protected areas and targeted conservation programs within the range of each genetically distinct variant of the Philippine tarsier.

Population viability analysis (PVA) has been increasingly used to guide conservation planning for many primate species. I present an assessment of a PVA for Philippine tarsiers (Tarsius syrichta) in Corella, Bohol. The objectives were to determine 1) area requirements and 2) spatial configurations of habitat patches necessary for viable populations in Corella. I used available life history parameters and ecological data for the Philippine tarsier derived from a radiotelemetry study on 4 male and 6 female Tarsius syrichta in Corella from early March to October 1999. I used analysis of the likelihood of extinction (ALEX), a Monte Carlo simulation model that uses pseudorandom numbers to simulate a scenario involving different stochastic processes. Sensitivity analysis showed that the model output, i.e. extinction risk, was influenced by the values used for newborn, juvenile, and adult mortality but the effect of variation on adult mortality was more pronounced; a slight increase in adult mortality renders the population very unstable. Simulation of movements between habitat patches showed that addition of diffusion corridors and variation in diffusion parameters did not significantly alter the probability of extinction of the species. Models are only as useful as the data that are input, and a major weakness of this model is the lack of detailed life history and mortality data for Philippine tarsiers. Future studies should concentrate on obtaining more life history data and ecological data from additional localities. I discuss key priorities for future research that include use of alternative PVA software, a simpler modeling approach, and extensive genetic studies of different Philippine tarsier island populations.

This study reports the isolation and characterization of eight microsatellite markers for the study of Philippine tarsiers (Tarsius syrichta), small primates endemic to this Southeast Asian archipelago. The markers were used to screen 14 Tarsius syrichta for allelic diversity. This suite of highly polymorphic microsatellites provides the first chance to genetically study parentage and dispersal patterns in Philippine tarsiers.