Saproxylic beetle (Coleoptera) communities and forest management practices in coniferous stands in southwest Nova Scotia, Canada

Peter Duinker,Christopher Majka,Philana Dollin

doi:10.3897/zookeys.2.15

Abstract

Old-growth forest in Nova Scotia typically exhibits an uneven-aged, multi-layered stand structure and contains significant amounts of coarse woody debris. Many forest species, including invertebrates, depend in various ways on deadwood substrates. The objective of this study was to investigate relationships between forest stand age, silvicultural treatment, dead wood, and invertebrate biodiversity, using saproxylic beetles as an indicator group. Saproxylic beetle communities were also compared in the context of other studies in Nova Scotia. Beetles were gathered using four collection techniques: pitfall traps, funnel traps, sweep-netting, and manual searching. Results show that both stand age and harvest treatment had an effect on species richness and species composition. Younger stands had lower species richness and hosted a significantly different suite of species than medium-aged or older ones. Similarly, harvested stands had lower species richness and were host to a significantly different suite of species than unharvested stands. The results from the investigation of stand age are of particular interest. Forest management that disregards the dependence of different suites of beetles on forest stands of various ages and compositions, emphasizing even-aged single-species stands, may be harmful to the species diversity of Nova Scotia's forest ecosystems.

Highlights

Many indicators have been developed for monitoring forest health and human impacts on forest ecosystems (Noss 1999)
Saproxylic beetles are a functional group of Coleoptera that depend, at some point in their life cycle, on dead or decaying wood or fungi associated with deadwood (Speight 1989; Økland et al 1996)
Do these insects comprise a large proportion of total forest species richness, but they play an important role in decomposition and nutrient cycling in forest ecosystems (Siitonen 2001; Grove 2002b)

Summary

Introduction

Many indicators have been developed for monitoring forest health and human impacts on forest ecosystems (Noss 1999). Saproxylic beetles are a functional group of Coleoptera that depend, at some point in their life cycle, on dead or decaying wood or fungi associated with deadwood (Speight 1989; Økland et al 1996). Do these insects comprise a large proportion of total forest species richness, but they play an important role in decomposition and nutrient cycling in forest ecosystems (Siitonen 2001; Grove 2002b). Saproxylic beetles are, in large part, responsible for the mechanical breakdown of coarse woody debris (CWD) (Hickin 1963). These beetles demonstrate sensitivity to timber-harvest practices (Simila et al 2002)

Objectives

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Results

Conclusion