De herontdekking van de Mercuurwaterjuffer (Coenagrion mercuriale) in Limburg (NL)

Geraeds, R.P.G. & T.O.V. Muusse, 2012. The rediscovery of Coenagrion mercuriale in the Dutch province of Limburg. Brachytron 15(1): 25-30. The Mercury Bluet (Coenagrion mercuriale) has always been rare in the Netherlands. Only two reliable sightings are known: in 1903 and 1926. However, on the 1st of June 2011, four or five male Southern damselflies were found in the Beesels Broek in the Dutch province of Limburg. In the following days, Southern damselflies were seen almost daily up and until the 13th of June; after the 13th none were spotted. Only males were seen, maximally five animals at a time. All animals were seen along a small part of the Huilbeek brook and a small seepage stream. Both streams do not look very suitable for the species. There is a lack of submergent vegetation that is suitable as larval habitat. Besides that, the Huilbeek brook is densely grown with Phragmites australis. Because of this, and the short 13-day period (early in the flight period that animals were seen), it is possible that there is no population present in this area of the Beesels Broek. It is most likely that the damselflies are vagrants from a nearby (undiscovered) population.