There are 32 species on the Irish dragonfly list. This includes 22 resident species, eleven Zygoptera and eleven Anisoptera. There are confirmed records of four vagrant species, and 19th Century records of an additional 3 species. The Golden-ringed Dragonfly Cordulegaster boltonii is unconfirmed whilst the status of the Highland Darter Sympetrum nigrescens as a distinct species is not universally accepted. Three species new to the Irish fauna were recorded in June and August of this year (see News).
The Irish Odonata fauna is a very depauperate one in comparison to adjoining regions in northern and western Europe. Comparative numbers of resident species include 37 in Great Britain, 64 in the Netherlands , 41 in Norway, 81 in France and 89 in Italy. The representation of Odonata species found in Ireland compared to Great Britain is close to the average, 60%, for the total freshwater insect fauna. One species, the Irish Damselfly Coenagrion lunulatum, is not found in Great Britain. The Zygoptera (damselflies) comprise 32% of the total European Odonata fauna (37 of the 114 species). The ratio of Zygoptera to Anisoptera tends to decrease with increasing latitude (Askew 1988). Ireland, however, is unusually rich in Zygoptera as these comprise 50% of the resident fauna. Comparative figures for other areas of north-west Europe are 40% in Great Britain, 39% in Netherlands, 37% in Norway and 37% in France.
A major study of the changes in the distribution of European butterflies since 1945 has shown that the ranges of a significant number of species have moved north 1945. This trend, which is cited as evidence for global warming, may also be affecting the European dragonflies. Since 1995, six dragonfly species have been recorded in Britain for the first time. Four species have established at least temporary breeding populations and marked northward range expansions have been seen in some resident species. In the Netherlands some previously vary rare species have been seen in increased numbers. This trend may simply reflect the heightened popularity of dragonflies amongst naturalists over the last ten to 15 years. However the events in Ireland over this summer would lend support to the suggestion that these observed changes are real and a result of global warming. The downside of colonisation by species from the south, may mean that we will lose our northern species. Species which could lose out in this are the Northern Emerald Somatochlora arctica, Downy Emerald Cordulia aenea and Irish Damselfly Coenagrion lunulatum. One of the main results of the DragonflyIreland project will be baseline data for future researchers to monitor changes in species ranges and distribution patterns.
|Nelson, B., Thompson, R. & Morrow, C., 2000 (September 12). [In] DragonflyIreland http://www.ulstermuseum.org.uk/dragonflyireland/|