The sustainability of a commercial harvest of the Arnhem Land cycad (Cycas arnhemica) by an Aboriginal community

: impacts on growth, survival and recruitment

Abstract

The commercial harvest of the endemic Arnhem Land cycad, Cycas arnhemica, provides an opportunity for the local Aboriginal community to establish a smallscale community-based enterprise. C. arnhemica is protected under Northern Territory and Commonwealth legislation and permits for commercial harvest are conditional upon monitoring of the population to ensure the sustainability of the harvest. An experimental harvesting and monitoring program was established by the Key Centre for Tropical Wildlife Management and Bawinanga Aboriginal Corporation (BAC) in 2001 to determine the effects of harvesting on growth, survival and recruitment of C. arnhemica. Monitoring was carried out in replicate harvest treatments using tagged individuals. The survival of harvested plants under a range of fungicide and rooting hormone treatments in the nursery was also investigated to minimise post-harvest loss of plants. A range of a priori candidate models was tested to determine which factors influenced cycad life history using information-theoretic methods. Harvesting was not found to have an effect on life history traits of the population. Survival, recruitment and growth did not differ significantly between harvested and unharvested populations. Survival of C. arnhemica in the nursery was not affected by hormone and fungicide treatment compared to untreated control plants but long-term storage of plants without soil led to high mortality. The harvest of C. arnhemica at the current rate of 500 individuals per year appears to be sustainable. Recommendations are made to ensure the continued sustainability of the harvest.

Date of Award	Nov 2003
Original language	English
Supervisor	Anthony Griffiths (Supervisor)