By Marlies Nicolai, Auchnerran Research Assistant
The peak survey season has begun at the Game and Wildlife Scottish Demonstration Farm, Auchnerran so it’s currently all hands to the pump! In a few weeks’ time a dragon fly (Odonata) survey will be completed around the main pond on the property to try and identify the species of adult dragon flies present.
However, at this time of year we have the opportunity to survey the invertebrate fauna within the pond to identify which dragon fly species are present in their nymph stage, plus look at a range of other beasties that might be present.
As dragon flies spend the majority of their lives in the nymph stage (sometimes as long as four years), there is often an increased chance of coming across a greater variety of species while dabbling in the pond. This means some species may not be recorded in the summer adult dragon fly survey as they have not yet matured and will not be seen flying around the pond and settling on nearby vegetation.
Last week a fresh water invertebrate enthusiast and dragon fly expert, Juliette Dinning, came to survey the pond. The dabbling activity focused on identifying larger invertebrate species and revealed a fantastic variety of species present, including Large Red Damselfly, Summer Mayfly, a number of larval caddisfly species, alderfly larvae, emerging stonefly larvae, lesser water boatman, water crickets, bloodworms, freshwater shrimp, pea mussels (a very small freshwater bivalve) and pond snails!
Non-invertebrate animals including toads and fish were also seen swimming around the pond. All in all the species found indicate a very healthy fresh water system and they provide an environment with a suitable food source for birds including waders, dippers and wildfowl.
The survey revealed only one species of dragon fly, the Large Red Damselfly, however a previous survey recorded Four Spotted Chasers. During the next few weeks it is hoped that further surveys will reveal a greater variety of dragon flies and other fresh water invertebrate species.