A review of potential biodiversity indicators for application in British forests

A review of potential indicators of biodiversity in British forests is presented, with a focus on the usefulness of selected biotic parameters as surrogate measures of different aspects of biodiversity in managed forests. To be effective in this respect, indicators must satisfy a number of criteria. They must be readily quantifiable, easily assessed in the field, repeatable and subject to minimal observer bias, cost effective, and ecologically meaningful (i.e. close association with, and identification of, the conditions and responses of other species). It is suggested that a combination of structural (physiognomy of stands and associated structures) and compositional indicators (indicator species or species groups) is selected which is appropriate to the aims of management and to the particular forest type in question. A useful approach is to identify two to three key compositional indicators, shown to be functionally linked to a broad range of other species, such as the extent and species composition of the broadleaved component in conifer forests; and two to three key structural indicators, which act as surrogates for general species richness or diversity, such as the quantity and quality of deadwood.