Biodiversity indicators: graphical techniques, smoothing and searching for what makes relationships work

Knowledge of the distribution of biodiversity remains poor. This situation might more readily be resolved if the species richness of certain groups of organisms indicated the richness of other, less well known groups. A spatially explicit exploration of the pattern in the predictive power that one taxon (a potential 'indicator group') might have for the diversity of another has been performed previously, In this paper we respond to three important points that have been raised. First, we describe an additional graphical technique for visualising spatial aspects of indicator relationships. Second, we examine some of the consequences of smoothing species richness data on observed indicator relationships. Third, we consider some of the factors that may contribute to strong indicator relationships.