In the past fifty years, the numbers of the Small Pearlbordered Fritillary (Clossiana selene) in Flanders have declined alarmingly. The species has now virtually become extinct. The cause appears to be habitat destruction and the loss of the butterfly’s foodplant, the marsh violet (Viola palustris). Drainage and use of fertilizers in marshes and grasslands have resulted in the loss of the Small Pearlbordered Fritillary. Colonization from other populations is unlikely as the distances are too great. Reintroduction may be a possibility in the future.