Honing Red List Assessments of lesser-known taxa in biodiversity hotspots
Red Listing organisms is an iterative process involving two variables. First, the conservation status of a taxon becomes clearer as more information becomes available, and secondly, the actual status changes as the taxon becomes more threatened or less threatened. Using a 20-year database of South African dragonflies has enabled us to hone conservation assessments and to arrive at a realistic appraisal of their true conservation status. Changes in the evaluation of taxa came about through improved knowledge of habitat and particularly from information on the exact flight period. This background improved the apparency of the taxa so enabling accurate conservation assessments. The temporal shortcoming was addressed in detail by focusing on the core of the Cape Floristic Region global biodiversity hotspot, and recording the phenology of species. We found that there were large differences in emergence times. While flight times may not be a source of error in the temperate northern hemisphere, they can be a major issue in low and southern latitudes. Indeed, the error can be so great that species thought to be extinct were effectively resurrected. Temporal shortcomings can only be overcome by first undertaking a presence/absence survey over time to determine the appropriate time of year for making rigorous Red List assessments. This is not a criticism of the Red Listing process per se, which, for this taxon, we found to be largely sound. However, the results do emphasize that a critical approach to methodology is a necessary foundation when searching for trend indicators from the Red List with regards to lesser-known taxa. © 2006 Springer.