Karl Harrison, UES’ Graduate Ecologist, recently attended a freshwater invertebrate survey run by the RSPB at Coombes Valley Nature Reserve, Staffordshire.
The site is an oak woodland located in the steep sided Coombes Valley. It attracts a variety of woodland breeding birds including; flycatchers, redstarts and wood warblers. The site also has a small population of rare Argent and Sable moths (see photo).
The samples were taken from a stretch of the Coombes Brook as it passes through the nature reserve. They were collected using the ‘kick-sampling’ method, where the substrate is disturbed up stream of a hand net which collects any small invertebrates and everything else flowing down stream. The content of the net was spread out on a tray and any invertebrates carefully collected.
In the makeshift laboratory the collected samples were analysed and compared to known samples, paying close attention to the features that distinguish one family from another. The invertebrate larvae we hoped to identify were Mayflies Ephemeroptera, Stoneflies Plecoptera, Caddisflies Trichoptera and True flies Diptera.
Freshwater invertebrates are a good indicator of water quality, usually determined based on the species present and their levels. For example an abundance of Stonefly and Mayfly larvae suggests good oxygen levels and low levels of pollution.
The study of freshwater invertebrates can be very useful in ecological surveys, as they provide an indication of water quality and potential presence of amphibians.
Karl will be returning to Coombes Valley Nature Reserve to observe the larvae through their development.
For more information about the reserve or volunteering with the RSPB, details can be found on the Coombes Valley Nature Reserve Webpage.