Monday, 8 September 2014

Wicken Welcomes some Old Residents

We have a guest contributor to the blog today, Stuart Warrington, our regional wildlife advisor:

On Friday 6th September, we had one of those days that makes our job so varied and interesting.

150 former residents of Wicken Fen were brought down the A1(M) from York to try to get them re-established on the fen. These former residents were beetles, called Tansy beetles, and they travelled in two buckets in the boot of car!

The Tansy beetle (scientific name Chrysolina graminis from the 'leaf beetle' family) is a very rare species and it used to occur at Wicken but it was lost from the Fen more than 3 decades ago. We don't know exactly why it was lost, but at that time the fen was rather dry and scrubby. After all of our work clearing scrub and getting better control of the water levels, and creating new habitats too, we are much more hopeful that the conditions are right again for this rare beetle.

The beautiful Tansy Beetle (Chrysolina graminis)

The project is a joint one between The National Trust, Buglife and the Tansy Beetle Action Group (TBAG), supported by Natural England. The beetle is currently known only in Britain from York and Woodwalton Fen, where a small number were rediscovered earlier this summer. The beetle’s only stronghold has been along a 30km stretch of the River Ouse, around York, where it mainly eats tansy (Tanacetum vulgare), a perennial herb which has given the beetle its name. It will also feed on water mint and gipsywort, which are both very abundant at Woodwalton and Wicken fens.

The tansy beetle had a bumper summer in York so there are many thousands of adults present. Thus a few have been released at Wicken Fen so they can feed up through September on their food plants and hopefully will emerge from hibernation next spring. We shall go and have a look next May. The re-introduction project, especially with a little insect, is partly an act of faith, as we really don't know if it will thrive at Wicken. But it is certainly worth trying to put the insect back into its former sites, to help bolster its population and reduce the risk of extinction.

The Tansy beetle is a very pretty iridescent green beetle, about 8-10mm in size. The project captured the interest of the media, and both Anglia TV and BBC East came along to film the release of the beetles. The camera-men were very pleased with how pretty the beetle looked in close-up, with the autumn sunshine bringing out the colours very nicely. The two presenters were also very happy to be out at Wicken doing a good news story, and they all stayed for tea and cakes in the café.

TV crews getting excited about the beetle
We tend to take the philosophy of the "Field of Dreams" in our habitat creation at Wicken, which is "if you built it they will come" (it's a 1989 Kevin Costner film). And many species have taken advantage of the extra space and wildlife habitats we have made south of our classic Sedge Fen. However, in this case, it is a very long way for a small rare beetle to get to Wicken Fen (especially as it is very reluctant to fly and tends to walk between its food plants), so it's been given a helping hand!