Dragonflies and the vegetation succession in marshes, bogs and swamps
In the 20th century there was a sharp decline in the dragonfly species characteristic of carr peat bogs. The main factors responsible for this are the effects of water draw-down and eutrophication, coupled with the disappearance of young stages of the terrestrialisation of bog.
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Trends
During the 20th century the group of dragonfly species characteristic of carr peat bogs, including large white-faced darter and Sympecma paedisca, dwindled dramatically.
The large white-faced darter (Leucorrhinia perctoralis) is a characteristic species of the richly structured terrestrialising vegetations in water bodies that still have about half of their surface unvegetated. Sympecma paedisca also shares this habitat, but in autumn seeks out sheltered sparse reed vegetations on the land, where it hunts for food. The distributions of both species shrank dramatically in the 20th century.
Causes
Many carr peat bogs have been encroached by trees, because the vegetation succession has proceeded unhindered. This has led to a sharp decrease in the habitat suitable for dragonflies. Concomitantly, the quality of the remaining areas has declined because of the effects of water draw-down and the eutrophication of the surface water. They are therefore no longer suitable habitats.
The large white-faced darter and Sympecma paedisca are on the Red List of dragonflies.
