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Project summary:
Abstract
Pitfall samples of the invertebrate litter fauna were collected from sites in seven coupes at Warra in the Southern Forests of Tasmania. Some were taken prior to any logging activity and some after logging and post-logging treatment. After sorting, these samples yielded 1011 specimens of non-marine molluscs from which 22 species were identified. Only 3 species were collected in post logging samples from treatment sites. Hand collecting in the control coupe realised 15 species. The results from this study are presented, inferences drawn about the effect of logging operations on the forest mollusc fauna, and assessment made of the usefulness of the pitfall trap collecting method for studies on mollusc populations.
Methodology: In the SST study seven coupes are designated for the study, with from 2 to 4 monitoring sites being established in each coupe. At each of these sites 10 pitfall traps, arranged in regularly spaced pairs (separated by 1-2 m) along a 50 m transect, were set up. Monthly samples were collected both pre and post treatment. Pitfalls were re-established at marked pre treatment sites as soon as the treatment had been completed and all ran for 13 months post treatment. The data for 2004 is from the first three months of monitoring of site three years after treatment. Samples were processed in the laboratory and all the molluscs separated, and sent to Queen Victoria Museum and Art Gallery, Launceston for identification. The SST pre-logging samples were taken before any logging activity or treatment was commenced.
Pitfall trapping was conducted in the Control coupe for 26 months ending in November 1999. Pitfalls were re-established in the Control coupe in September 2004 at the same time that pits were replaced in other treatment coupes. Hand sampling was conducted in November 2000 in the Control coupe at the same time that initial post logging pitfall sampling was conducted in treated coupes. Hand sampling was carried out at Warra for three days, mainly in the WR008J Control coupe and in several adjacent unlogged coupes. No attempt was made to assess the size of populations, but notes were made of species present and a judgement made about ease of sampling as a measure of relative abundance. Searches were made of all the likely habitats based on the experience of the collectors. Random searches under logs and rocks as well as bark and tree trunks for arboreal species were conducted.
All molluscan material was examined in the laboratory and assigned to a genus or species. Unless the material was very badly damaged it was lodged in the reference collections of the Queen Victoria Museum and Art Gallery, where it is available for further study.
Datasets: None available.
Publications: Smith, B.J., Bonham, K. & Bashford, R. (2005). Use of pitfall traps to monitor the composition of the molluscan fauna before and after silvicultural logging treatments at the Warra LTER Site in southern Tasmania. Unpublished report, Forestry Tasmania, Hobart.
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