Forest connectivity is important for sustaining Admiralty cuscus (Spilocuscus kraemeri) in traditional terrestrial no-take areas on Manus Island, Papua New Guinea

Abstract

Tambu is a well respected concept in Melanesian societies and represents a periodic cultural restriction on harvesting for the purpose of fulfilling customary obligations and restocking resources. As a result it has been suggested as the basis for conservation and sustainability in Melanesia. One species subject to tambu management is the Admiralty cuscus (Spilocuscus kraemeri), an arboreal marsupial endemic to Manus Island, Papua New Guinea, where it is a major source of terrestrial protein for forest-dwelling villagers. We investigated the denning home range and movement patterns of 10 cuscus using radio-telemetry in and around a 21-ha forested tambu area over a 28-day period. Home-range sizes were estimated using a 95% minimum convex polygon method and possible contributing factors to home-range size were assessed through model selection. Home-range size was highly variable, log-normally distributed (back-transformed mean = 2.9 ha, mean ±1 s.d.: 0.6–13.8 ha, n = 8), and was not associated with body mass, age or sex. Additional telemetry data collected from three S. kraemeri over 74 days appeared to support the stable nature of the home ranges. Through application of Laplace’s extension of the Buffon’s needle problem we conclude that, despite potentially high growth rates and short juvenile dispersal distances, tambu areas are unlikely to be self-sustaining. We hypothesise that the apparent efficacy of tambu areas is a consequence of forest connectivity that allows the immigration of adult founders to offset losses in reproductive stock coming as a result of periodic harvest and juvenile dispersal.