Modelling the impact of timber harvesting on a rare carnivorous land snail(Tasmaphena lamproides) in northwest Tasmania, Australia

A stage-structured, stochastic metapopulation model was developed for a rar e carnivorous snail, Tasmaphena lamproides, occurring in production forest in northwest Tasmania, Australia. The model was used to investigate the imp act of a range of plantation options and harvesting strategies. These inclu ded: (i) a proposed 'District plan' with a combination of plantation conver sion and native-forest harvesting: (ii) a 'plantation' scenario where all s uitable areas within the forest are converted to plantation: and (iii) a 'n ative forest' scenario where all areas are harvested to a schedule and rege nerated to native forest. The model facilitates exploration of management o ptions and their consequences in terms of their effects on average populati on sizes and risk of decline of T. lamproides. The results suggest that ret ention of contiguous areas regenerated to native forest, the timing of harv est activities, and the management of dispersal barriers may be important e lements of a successful management strategy for T. lamproides. A detailed a nalysis was conducted to determine the sensitivity of the model to small ch anges in parameter estimates and assumptions. This sensitivity analysis can be used to highlight the features of the model that require a more extensi ve investigation and to guide future research into the conservation of T. l amproides. (C) 2001 Elsevier Science B.V. All rights reserved.