Reintroducing Water Voles to Northamptonshire – The Stanwick Lakes Project
This spring, the team at Stanwick Lakes were extremely excited to be releasing water voles back into our rivers. These small but mighty creatures, commonly called water rats, are small brown rodents with a blunt nose and furry tail. As herbivores, and very good ones at that, water voles have a diet of over 220 species of aquatic vegetation. Eating 80% of their body weight each day earns them a good long rest in their riverside burrows at night. These burrows can be quite extensive, sometimes having both an underwater and an on-land entrance. By using latrine sites where they poo to mark their territory, they fend off competition and keep their burrows clean and tidy. The voles live a quick and busy life, having 30-40 young within their 6-18 month lifespan. The offspring leave their mothers early on, going on to breed themselves not long after. They remain close by, forming a family community along a stretch of river.
Ecosystem Engineer
A species which creates or changes habitats for other species, through its natural behaviours.
Why Water Voles Matter for Wetland Ecosystems
The effects of their eating and burrowing behaviours are so strong that it earns them the title “Ecosystem Engineer”. The phrase has become somewhat of a buzzword in recent news as wildlife reintroductions become more widespread, but we shouldn’t lose sight of its importance. Without meaning to, ecosystem engineers benefit other species that share their environment. Water voles do this in several ways; their burrows create homes for other species like insects and other small mammals, especially once they become vacant of their original inhabitant. The burrows, though, have other indirect effects. Since an organism (or isms) is living in the burrow, new nutrients and nitrates enter the soil. Any gardeners will know the importance of the soil health and balance for plant growth, and the same is true in nature. Different plants prefer this new soil makeup, allowing for new plants to thrive. Because of this, new pollinators are attracted, which will attract new prey such as birds. Now we can see how a small, natural behaviour from the water vole can change its surrounding ecosystem, almost like it’s engineering it…
The Decline of Water Voles in the UK
We require a reintroduction for these mighty little beasts because of the incredible decline in numbers they have faced. They’re the UK’s most rapidly declining mammal, losing 90-97% of the population since 1950. Many visitors we speak to at Stanwick Lakes describe growing up, walking along the rivers and seeing water voles as a common sight. Nowadays you’d be extremely lucky too, as they have lost 94% of their distribution. Some bleak truths in and of themselves; however, it must be stressed that along with this loss, so too goes all those benefits they bring. The biodiversity of our rivers takes a hit when we lose such an important species.
The American Mink, whose name features a big clue as to where they originate, was brought over from the USA for their fur. In the 1920s, fur was all the rage, which made it very profitable, and we Brits wanted some of the action. So, we brought over huge numbers of mink to breed in fur farms. Eventually the voices of animal welfare activists were heard by the government, and fur farming legislation was changed. The mink farmers now had a choice: kill all the mink or let them out into the wild. I imagine some of them thought it was the more humane option to allow them to run free in the great countryside. However, releasing a vicious predator into our ecosystem was not the best decision. With no natural predators, and prey (voles and such) who have not evolved alongside them, the mink had a veritable buffet on its hands. Our native predator and prey species have all been in an evolutionary arms race all this time, constantly evolving traits to one-up each other. As the prey gets faster, so does the predator and so on. With evolution being such a slow process, our species had no chance to develop ways to escape the American mink. Particularly devastating for the water vole is that their natural defence of swimming into their burrows to escape otters and herons is useless against the mink. The female mink is small enough to fit inside and will devastate an entire family group, systematically wiping out voles as it travels along the rivers. It becomes clear now, as we’ve pushed the water voles into tiny pockets and released an incredible predator into the mix, how we ended up with such a devastating decline.Creating Habitat for Water Voles at Stanwick Lakes
As we caused this problem, it is up to us to fix it. To mitigate the habitat loss, we need to create or find suitable habitats for them. Cleaning our rivers, protecting them from further human encroachments and connecting the isolated water vole populations is key. But what does a good habitat for water voles look like? Well, it needs dense vegetation for both cover and food, a constant clean water supply, and soft undisturbed banks for burrowing. Stanwick Lakes already ticked so many of these boxes due to our longstanding work improving our habitats. We had to create fencing to protect the banks from trampling cattle, but other than that, we were prime candidates! Across the country, farmers, nature reserves and landowners have successfully created or offered great places for water voles to live, and reintroductions are popping up as a result. Doing this benefits not only the water voles (and the species they will then go on to benefit) but also coots, moorhens, water rails, kingfishers and more!
Reintroducing and Monitoring Water Voles
After doing these initial steps, a full-on reintroduction can take place. We teamed up with The Wildlife Trust for Bedfordshire, Cambridgeshire and Northamptonshire, who were the lead on a bid to Natural England’s Species Recovery Programme Capital Grants Scheme. Thankfully the bid was successful and funding was received to release water voles at both our neighbouring Wildlife Trust site, Nene Wetlands, and at Stanwick Lakes. Without TWTBCN, we would not have been able to do this release; the generosity and experience they provided were essential, and we are so appreciative! Once water voles were available (there is a national shortage of water vole breeders, as it happens!), they were delivered in their travel cases and had a sleepover in the ranger cabin. The next morning, a big group of us built them pens which they would stay in for a few days, acclimatising to their new environment. We went back each day to feed them, which involved two river crossings in waders stuffed with carrots each time. Anything for our voles! Then, the pens were opened so the voles could leave if they wanted to, and eventually we collected in the pens once all voles had gone off into the big wide world. This method of releasing wildlife is called a ‘soft release’, as opposed to a hard release where you let the animal straight out with some best wishes. Over 30 of our amazing Stanwick Lakes volunteers joined us for a lot of this process, many of whom had been involved in water vole habitat surveys, field sign identification training and building fences to improve the riverbanks for the voles. The feelings on the day were pure excitement and joy that our hard work had paid off. We were very lucky to be a part of this, and our hard work was rewarded with being able to see many water voles over the course of the week and the fulfilment of completing something so special to us.
How You Can Help Water Voles
You can play your part in our water vole reintroduction and be the eyes and ears around the nature reserve. Have you seen any signs of water voles at Stanwick Lakes – or even a water vole itself?! If you have, please let us know by emailing nature@rftrust.org.uk. Tell us when you saw it, the location, and attach a photo. We’d love to have a look ourselves and want to know that the voles are doing well. But we’d also like to know that our visitors are being able to see signs (or even voles themselves!), as we love to know that such a nostalgic species can again be seen.
At Stanwick Lakes this release has been of huge importance. We have benefitted water voles and other wildlife and been able to offer our hard-working volunteers the chance to be involved, and we send a huge thank you to them. We also give thanks to The Wildlife Trust, Waterlife Recovery Trust, Natural England and Derek Gow Consultancy. All of these were crucial in making this happen for us, so thank you! We pat ourselves on the back too, of course.
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