We have added three species of Odonata (dragonflies and damselflies) to our species lists this year. They have raised our total to a round dozen.
Twelve is a very encouraging number. There is this thing that Natural England and DEFRA call an outstanding assemblage of species; an outstanding assemblage of Odonata is one of the criteria by which a stream might be selected as a Site of Special Scientific Interest (SSSI). An outstanding assemblage of dragonflies and damselflies in southern England appears to be fifteen to seventeen species.
Here are the three new species:
Anax imperator Emperor Dragonfly identified by Ian Bushell 26/07/19
Ischnura elegans Blue-tailed Damselfly seen and photographed by Ian Bushell 16/07/19
Sympetrum sanguineum Ruddy Darter reported by Ian Bushell 04/07/19
We need just three or four more species of dragonflies and damselflies to make an outstanding assemblage. Keep a look out for us come the summer of 2020.
“Where a site has a number of species [of Odonata] that meets or exceeds a number considered to form an outstanding assemblage, the site should be considered for selection. This number varies across Britain: 15 – 17 species for southern England.”From the Handbook of Biodiversity Methods: Survey, Evaluation and Monitoring edited by David Hill, Matthew Fasham, Graham Tucker, Michael Shewry, Philip Shaw