Tree biology and saproxylic Coleoptera: issues of defi nitions and conservation language

Abstract

The most widely used definition of saproxylic invertebrates is the one presented by Martin Speight in Saproxylic invertebrates and their conservation (Council of Europe, 1989). That definition however associates saproxylic organisms principally with ‘moribund or dead trees’. It is now appreciated that healthy living trees are arguably more important for many saproxylic invertebrates and so the definition requires modification. A new revised definition is that saproxylic organisms are species which are involved in or dependent on the process of fungal decay of wood, or on the products of that decay, and which are associated with living as well as dead trees. Conventionally two further groupings of organisms are included within the definition : i) sap-run associates, i. e. species dependent on fluxes of sap and its decomposition products, and ii) organisms other than fungi that feed directly on wood. A basic understanding of the key aspects of tree biology and tree ecology – the aging and decay processes of trees as well as tree form and tree habitats – is an essential tool for invertebrate specialists involved in the key conservation of saproxylic Coleoptera. A good appreciation of tree terminology is also essential if we are to successfully promote conservation of saproxylic Coleoptera.