Testing the applicability of regional IUCN Red List criteria on ladybirds (Coleoptera, Coccinellidae) in Flanders (north Belgium): opportunities for conservation

1. Red Lists assess the extinction risk of species and are an important tool to prioritise species conservation and management measures. Worldwide, quantitative IUCN criteria are used to estimate the threat status of species at the regional level. 2. In Flanders (north Belgium), about 70 000 distribution records of ladybirds were collected in 36% of all the grid cells (1 9 1 km 2) since 1990 during a large-scale citizen-science project. 3. Applying the IUCN criteria to the 36 resident 'conspicuous' ladybirds in Flanders resulted in two Regionally Extinct species, three Endangered species and six Vulnerable species. A further seven species were considered Near Threatened and the remaining 15 species (39%) were assessed as Least Concern. Three species were classified as Data deficient. Using the Red List status, we delineated ladybird hotspots that were mainly located in grid cells with large areas of Natura2000 sites. 4. For calculating a distribution trend, we advocate the use of a high grid cell resolution (e.g. 1 x 1 km(2) or 5 x 5 km(2)). 5. The ladybird data set from Flanders provides evidence that IUCN Red List criteria can be applied to this charismatic, but relatively under-surveyed insect group. For estimating the geographic range, the use of extent of occurrence instead of area of occupancy is advisable when the survey coverage is relatively low. We discuss the opportunities of the availability of a ladybird Red List for regional conservation measures.