A practical technique for non-destructive monitoring of soil surface invertebrates for ecological restoration programmes

Authors

  • Mike H. Bowie,

  • Chris M. Frampton


  • This paper is based on research by Mike Bowie, an entomologist in the Ecology and Entomology Group (PO Box 84, Lincoln University, Canterbury, New Zealand. Tel. (+64-3) 3252811, Fax: (+64-3) 3253844, Email: bowie@lincoln.ac.nz) and Chris Frampton a statistician with Applied Computing, Maths and Statistics Group, PO Box 84, Lincoln University. This project was undertaken to establish a practical technique to restore and monitor carabids and other invertebrates on Quail Island.

Abstract

Summary  This study investigates the suitability of using wooden discs as facsimiles for natural fallen logs to non-destructively monitor invertebrates. Wooden discs cut from tree trunks were placed on the ground at five sites and monitored. A diverse range of species was found under the discs including large numbers of some species. On Quail Island, Pine, Macrocarpa, Oak and Beech discs were compared. Beech discs had significantly fewer invertebrates and recognizable taxonomic units than other disc types. Pine discs had significantly more flatworms than the other three disc types. A comparison of invertebrate numbers when discs were placed directly on soil or grass indicated that larger numbers of individuals and recognizable taxonomic units were found under discs placed on bare soil compared with those on grass. Discs with a soil cavity beneath had significantly fewer individuals and recognizable taxonomic units than discs without cavities. Carabids showed considerable seasonal variation, with highest numbers in spring and lowest in winter, and larger numbers were found under discs at moist sites. Skinks over-wintered under discs in drier open sites at Lincoln and Quail Island. Disc condition was assessed after 28 months and showed Macrocarpa had deteriorated the most of the four disc types. Wooden discs are a useful tool for the ecological management of terrestrial invertebrate fauna in restoration programmes for monitoring and considerable potential exists for discs to provide habitat for restoration of terrestrial invertebrate taxa.

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