I kept going back to that Lumbricus sp. that I was stuck on after my last garden earthworm foray, and after segment counting over and over it still kept coming out as L. festivus, an uncommon species. With some trepidation (not least because I had just volunteered to help with earthworm identification) I brought it into the Soil Biodiversity Group laboratory at the Natural History Museum for Dr David Jones to check. To my delight and relief my identification was correct bringing my garden earthworm species list to nine.
As mentioned, since I now have a wage and days off during the week I have been able to return to volunteer with the Soil Biodiversity Group helping to sort and identify the earthworms sampled on the NERC BESS project. With my Christmas money I bought my own copy of Sims and Gerald and am learning more advanced skills in earthworm identification, with David pointing out features and giving tips on identification when the key cannot be used, like the headless Octolasion cyaneum in the first sample I looked at.
I like to start by picking out all the immature worms, for the most part these cannot be identified to species but they can be assigned to an ecotype which can still be analysed, for example any pale coloured immature earthworms are the soil feeding endogenic type. Next I move on to the damaged worms, which can be a bit of a ‘worm jigsaw’, sometimes it is possible to identify them to species if enough features are still present. Then it is on to species level identification, so far I have identified eight species from two of the fields at the Aberdeen site. The most frequent species was Aporrectodea caliginosa; I have identified 162 in ‘my’ two fields so it is exciting when something else turns up!
I have also ‘met’ some species under the microscope for the first time, including the UK’s biggest earthworm species – Lumbricus terrestris, and at the opposite end of the scale the little L. castaneus. I will be in once a week identifying earthworms and looking forward to meeting more species as the samples go on.