There are 27 species of earthworms in the UK. We think. Surprisingly, for such a familiar animal, they are substantially under-recorded and the Earthworm Society of Britain is trying to address that. They are very keen to recruit new earthworm recorders – I attended a weekend of training complete with Earthworm Society membership and ID book which cost me only £15!
Everybody has seen earthworms in their garden or mooching inexplicably across the pavement. I knew about soil dwelling earthworms which make tunnels and leave casts, but I had no idea that earthworms can also be found in rotting logs or among leaf litter. So to learn about the ecology and ID of earthworms was completely new to me and quite fascinating.We spent the first day collecting earthworms from a variety of habitats around Powis Castle and FSC Preston Montford, including compost heaps, permanent grassland, leaf litter, wet woodland and meadow.
There is a specific method to the sampling, but essentially you dig up soil and sort through it to find as many worms as you can. Juvenile worms are counted and put back – you can tell which ones are juvenile as they don’t have a lump in the middle (this is the saddle which houses the reproductive parts). Adult worms are collected and placed in alcohol to kill them. This may seem unfair, but have you ever tried counting the segments on a wriggling worm under a microscope? Impossible. The only way to do it is to immobilise them and killing them is fairly effective for that purpose. Unfortunately it seems to be a necessity for earthworm recording, although I do think I might experiment with putting worms in the fridge to see whether this slows them down enough to identify without harming them.
Having gathered our worms and recorded a bonus great crested newt under a log, we repaired to the lab on the second day to identify our finds.
This was quite difficult to start with, but towards the end of the day I got the hang of things and identified a few earthworms all by myself 🙂
Visit the Tomorrow’s Biodiversity website for another report of the weekend and some nice pictures. If you’d like to find out more about earthworms, visit the Earthworm Society’s website and join them on an event near you soon – events are planned in London, Cumbria, Yorkshire and Northamptonshire in 2015.