Shortcuts for biodiversity evaluation: a review of terminology and recommendations for the use of target groups, bioindicators and surrogates

The terms related to rapid alternative routes for appraising species diversity (biodiversity assessment shortcuts), through the use of biodiversity target groups, indicator groups and other biodiversity surrogates are examined. Biodiversity target groups are selected for their methodological and taxonomical advantages, and the purpose of their use is the assessment of their own diversity patterns. The focus of biodiversity indicator groups is on assessing the health of the entire ecosystem or a part of it, with respect to a visible phenomenon. Biodiversity surrogates include taxa-for-taxa surrogates, higher taxa, morphospecies and environmental surrogates. These are faster, less expensive routes for assessing general biodiversity patterns as compared with taking complete biological inventories. These concepts are clarified, examples of their use are examined and the published studies that have implemented such shortcuts are also analysed. For the selection of biological groups according to biodiversity research goals we have also proposed general recommendations.