High vole-tage

Guess who is back at Athelney? No not beavers. Or wolves. Or the West Saxons. Smaller. That’s right, it’s water voles! We are not sure exactly when water voles (Arvicola amphibius) disappeared from the site - as they had been recorded in the recent past - but for the last couple of years at least since we acquired the land for rewilding they have been absent, despite numerous searches.

Our first clue that they had returned came earlier this year. Water voles make a distinct noise as they dash for the water - a loud, sharp ‘plop’ - and we began hearing this sound along the main channel around May, albeit only very occasionally.

Then just a couple of weeks ago we received the results of some eDNA analysis we conducted on site back in June. eDNA - or environmental DNA - is a way of identifying species using the residual DNA they shed into the environment. By taking samples of water and soil and having them analysed we can get a snapshot of some of the species using a site, and set a baseline to measure future changes.

Of course eDNA surveying is not faultless - it will only pick up species which have recently been in an area and left a little DNA behind, and there are a large number of species which we know use the site regularly which did not show up in the snapshot, but it is a useful tool, and in this case it revealed water vole DNA from a single ditch, prompting us to take a closer look (more on the eDNA results in a future post). Excitingly the same sample also showed the presence of water shrews - another aquatic predator and the UK’s only venomous mammal.

Finally, just last week, some ecologists managed to get down and do a sweep of some of the key ditches in the area, and confirmed what we had begun to suspect - that we have a thriving population of water voles across the north of the site, and probably elsewhere too. As this was their third time searching the same area, and both the previous surveys turned up nothing, we can be pretty sure this is a recent development.

The return of the water vole to Athelney is good news as the species has been in serious decline in recent decades. It is estimated that in 1900 there were perhaps 7-8 million of them across Britain, down to just 130,000 today. As well as being beautiful creatures in their own right, they are also an important part of our wetland ecosystems. Their burrows and holes provide habitat for other wildlife, and they are an important prey species for a range of larger animals.

The only complication is that we are planning to construct some scrapes at Athelney, starting this Autumn. Scrapes are long shallow ponds or ditches which are often used to create variation in fields and landscapes that have been ironed out by years of agriculture. We don’t do much, if any, intervention on our land (these are rewilding sites after all) but scrapes are a good initial action to speed up the recolonisation of hard-worked agricultural land and create wetland habitat. The idea is that we do the scrapes, and then let the land go from there. As well as constructing the scrapes we were planning to reprofile the sections of the ditch banks to make them less steep and uniform, and link up a couple of the water way.

The presence of the voles changes things a little. We will still be able to do the scrapes in the fields, as these will be well back from the banks where the voles are living, but it seems that unless we can work out a solution, we will not be in a position to reprofile the ditch banks any time soon. That’s just how it goes. The digging on the in-field scrapes is due to start in the next few weeks, so we’ll keep you posted with how it is going.

Please note: Survey work and water management (like scrape digging) is being funded largely by our partners at SLX and through the Big Give, which have provided dedicated funding for these activities.

A water vole. (Photo by Peter Trimming, from Wikipedia).