The context and potential sustainability of traditional terrestrial periodic tambu areas: insights from Manus Island, Papua New Guinea
Within the Pacific over the last two decades there has been greater recognition of the pre-existing tools within indigenous communities for natural resource management. Periodic tambu (Tok Pisin: a prohibition) is an indigenous resource management tool often used across Papua New Guinea. On Manus Island terrestrial periodic tambu areas are characterised by a cycle of resource closure followed by instantaneous harvest. We examine the differing application of periodic tambu areas by three different clans who are using the technique to restock areas with the Admiralty cuscus (Phalangeridae: Spilocuscus kraemeri), an arboreal possum-like marsupial. We examined the plausibility of cuscus population recovery over differing closure periods at three different harvest rates using a composite female-only population projection matrix approach based on the vital rates of closely related phalangerid surrogates. The resultant trajectories suggest that commonly used closure durations may allow recovery at low to medium harvest rates (10–30%) but not at high harvest rates (50%). From this we infer that periodic tambu areas may be a sustainable strategy for customary resource use of Admiralty cuscus at low to medium harvest rates. We found periodic tambu management on Manus Island to be culturally dynamic with clans differing with respect to their purpose, adherence to tradition, and hybridisation with modern land governance practices. Given the past difficulties of imposing exogenous conservation systems in Papua New Guinea, we advocate greater exploration of the merits of endogenous systems such as periodic tambu areas.