Some aspects of Odonata distribution in Belgium

Some results of the Belgium atlas project are presented here. More than 65,000 records have been collected by 500 volunteers. Distribution data are presented for three periods in 10 x 10 km UTM squares : <1950, 1950-1979 and >1980, and for the period 1990-2000 (the major part of the records) in 5 x 5 km squares. Due to special efforts in the '90's to obtain a high and detailed coverage of the whole country, 93.5% of al 10 x 10 km UTM squares have been investigated. During this recent period, also 63% of all 5 x5 km squares have records. In general, Flanders, the northern part, is much better investigated than the southern part, Walonia. In total, 69 species were ever observed in Belgium, 66 of them present in the '90's. Only 2 species, Nehalennia speciosa and Leucorrhinia caudalis are now extinct. For ten species, records were missing during one of the periods. For each species, we mention the status, based on the number of occupied grid cells (5x5 km) since 1990. The highest species diversity can be found in the northeast of Belgium, the Campine region. Other regions with a high diversity are localised in the extreme south, the Lorraine. A map of the recent distribution is given for five species. We hope that the information in this atlas will be helpful for conservation measures and as a starting point for more detailed research and monitoring.