Posted: Tuesday 11th August 2015 by James.A
On Monday 3rd August we went to Woodgate Valley Country Park for a staff away day.
When we got there we met inside the visitor’s center where we were introduced to Ellen from FIN (Freshwater Invertebrate Network). She told us about all the fantastic work FIN is doing to establish a biological monitoring program. Working alongside volunteer groups to enhance water habitats in public spaces, for the benefit of people and wildlife.
As a new staff member to the trust I was looking forward to this so I could get to know my colleagues better and learn some new skills! As I had never done any surveying before I was quite excited.
We started out the day by looking at preserved creatures through a microscope and identifying them using the FIN Stream Life ID Guide. Whilst doing this we identified such invertebrates as the Common Leech and Cranefly Lava. Then we used our skills to look at live creatures in a sample taken from the River Rea that morning. There were many creatures including Freshwater ‘Shrimp” and over 100 Cased Caddis fly larva. This is good news as the Cased Caddis are sensitive to pollution. After looking through the samples we calculated a BWMP score of 67.3 which indicates good water quality.
Shortly after we headed out into the Valley to take some samples of our own. We chose to survey the two locations already surveyed by the Woodgate Valley FIN Group in order to compare results. The first location was ‘Black Bridge’ where we took turns kick sampling the brook, then looking at the results. We found many species including Plume Midge Larva and Wandering Snails and many other pollution tolerant creatures. After totaling up the score we got a BWMP total of 34.3 which indicates moderate water quality similar to other surveys taken earlier in the year.
On the way to the next survey the group decided to take a small detour and look at work improvements being carried out by the Environment Agency, where they had modified and removed weirs in order to naturalise the brook and improve the flow. As part of the work a section of the Bourn Brook was realigned to completely bypass the concrete weir. Our second sample was taken just downstream of the new channel.
This part of the brook was much more free flowing and shallower. We again found Freshwater ‘Shrimp’, Water Slaters and Olive Mayflies. While we were here we also saw a few common frogs. 
The results gave us a BWMP score of 28.1, quite a low score compared to the last survey taken in March.
However both surveys revealed ‘Jenkins Spine Snails’, more commonly known as the New Zealand Mud Snail, originally from New Zealand but thought to have been in England since around 1859. The Jenkins Spine Snail is an invasive species and now has found homes all over the world including the Americas, Asia and mainland Europe. Although invasive the spine shell is not harmful to British Wildlife. Interestingly the snails worldwide success is probably down to how indestructible they are! Did you know a New Zealand Mud Snail can pass through the guts of a bird or fish and survive?
We had a fantastic day and learned many new things about the species living in Woodgate Valley’s Bourn Brook!
If you would like to get involved with FIN and help sample and survey your local body of water visit: http://www.yourstream.org.uk/get-involved/
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