Cross-taxon congruence in complementarity and conservation of temperate biodiversity

Identification of reliable surrogate indicator taxa and effective shortcuts for the preservation of overall biodiversity is a major challenge. Encouragingly, complementarity-derived priority sets of focal taxa were found highly effective in representing non-target taxa in a study from Ugandan forests. It has been proposed cross-taxon congruence in complementarity is less distinct in temperate regions than in the tropics, because temperate regions have fewer species, and hence focal taxa may be less effective as they are less diverse. To test this, we used all available atlas data (10 x 10 km scale) in Denmark (butterflies, birds, amphibians, reptiles, large moths, bats and click beetles, n = 434 species), and looked at whether conservation priority areas based on one taxonomic group represent species richness of other groups in a highly fragmented landscape. We apply a new approach (based on G-statistics) that enables statistical evaluation of cross-taxon congruence in complementarity-derived priority sets. We found indications that the same taxa represented other groups effectively and exhibited cross-taxon congruence in complementarity-derived priority sets. Birds performed significantly, but relatively poorly, butterflies somewhat better and bats relatively well in representing species richness of other groups. Large moths performed best and may be an overlooked predictor of diversity in other animal taxa.