Wildlife habitat strips and native forest ground-active beetle assemblages in plantation nodes in northeast Tasmania

Authors


*Author to whom correspondence should be addressed (email: simon.grove@forestrytas.com.au).

Abstract

Abstract  In Tasmania, plantation establishment is often concentrated in ‘nodes’, a practice that can result in a high degree of fragmentation of remaining native forest in these areas. In this study we examined the sensitivity of ground-active beetles to the effects of conversion of native forest to plantation in which remaining native forest is largely confined to narrow wildlife habitat strips. At five damp sclerophyll forest sites in northeast Tasmania, pitfall sampling was carried out along the middle axis of a wildlife habitat strip, in the young plantation surrounding the strip, and at three distances in from the edge of nearby continuous native forest. The study documented a rich fauna, particularly for carabids. Species composition varied among sites, emphasising the need for adequate regional reservation of native forest at appropriate spatial scales. While plots in plantations and strips supported similar numbers of species as continuous native forest, they usually differed in assemblage composition. In general, assemblages in strips appeared to be intermediate in composition between those of continuous native forest and plantations. Significant differences corresponding to a progressive change in assemblage composition with distance into continuous native forest from its edge were detected for one, possibly two, sites. Plots in strips were generally more similar in assemblage composition to those near the edge of continuous native forest than to those towards its interior. Within the study area, strips may promote the survival of species that otherwise associate with the edges of continuous native forest, but they may provide less effective habitat for species that associate with native forest interiors. However, they still harbour many native forest species which are rare or absent in plantations. Although only based on a short-term sampling program, the study implies that future strips in Tasmanian damp sclerophyll forest could better benefit some forest interior species if prescriptions were to specify wider strips. However, a clearer conservation outcome might be to ensure the continuance of a sufficiently comprehensive, adequate and representative network of native forest formal reserves (in addition to wildlife habitat strips) containing damp sclerophyll forest. These should be large enough to cater for forest interior species, and dispersed at a spatial scale appropriate to the rate of species turnover found among ground-active beetle assemblages in these forests.

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