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Almost 4 years ago, we released 219 water rats on this farm right here in the Cornish countryside. And these, well, they were no ordinary rats. In fact, technically speaking, they were not rats at all. They were water voles, key riverside engineers, prolific burrowers that change their environment for the benefit of plants and other animals. So, when they disappeared from this landscape in the '90s due to habitat loss and the spread of invasive species, these streams became less biodiverse, less healthy, less alive. But, with changing conditions, the opportunity came about to try and bring them back, which is what we decided to do in 2022 when we funded this release. And now that some years have passed,
it's time to see whether it was all worth it. So, I asked Lilly, one of our biologists at our Scottish team, to head down to Cornwall and see what she could find. So, we've just arrived at the release site that just under 4 years ago, we released 219 little voles into this reservoir right here. And it's so exciting to be able to come back and see the result of a intervention that we put in place so long ago, but it's had so much impact. And before we go vole tracking, just a reminder that the only reason we can do this work here and at all our other projects, and the reason we can follow up on all of this years and years later, is because of our Mossy Earth members who support us with a monthly subscription. And if many of you
watching this video would decide to join today, we could do a lot more of this kind of work. Because for you, it can be as small as the cost of a fancy coffee each month, but for us, when there's many of you contributing, we can do really big projects, which is incredibly exciting. So, if you're keen to help us out to do these projects, then please consider becoming a member at mossy.earth. Now, first, to get this story I think it is important to remind you why these little furballs matter so much. And for that, I think we have to highlight primarily their dual role as an ecosystem engineer and a keystone species, which all comes down to what
they eat, what eats them, and how they build their complex homes. Firstly, we have what they eat. They're voracious herbivores that will nibble on any little bits of vegetation alongside river banks and encourage and increase diversity of plants. You see, in order to sustain their high energy levels, they eat up to 80% of their own body weight each day, picking from a mix of bankside grasses, sedges, reeds, and rushes, all the way to roots, rhizomes, bulbs, and even bark in cooler seasons. They really are not picky eaters and can devour over 200 different plant species. So, in effect, they behave like an army of many gardeners, preventing any one plant species from dominating and thus creating the space
and the light gaps for a diversity of riverside vegetation to flourish, which in turn helps insects and pollinators and so on. Now, their second big function is one that I'm sure they are less pleased with. So, they're food for a lot of different animals. I've seen about five buzzards circling up here today, and they're a hugely important prey item for a lot of predators that live here. This part of their role should not be understated because they are solving an important trophic bottleneck. You see, these riverbanks have abundant vegetation, loads of calories and energy, but few animals that actually eat this. So, when the water voles
convert the abundant but hard-to-digest vegetation into a bounty of easy-to-digest mammal meat, this benefits all kinds of predator species, ranging from birds such as owls, kestrels, and herons, to mammals such as foxes, otters, weasels, and stoats, among many others. And then, thirdly, we have the impact that they make on the streams themselves. Water voles build their burrows with lots of entrances and exits. So, they have some above ground like this one, some on the side of the river bank, and some underwater as well. And these form a really complex system that encourages the river to meander more freely, and it often even causes collapses in the river bank, which again encourages the river to keep meandering, keep flowing in its unique way.
Besides shaping the river flow, all of these holes break up the compacted soil into a sponge-like porous system. This allows air in, bringing oxygen deep into the soil, which triggers a microbial boom, which turns organic waste into easily accessible nitrogen and phosphorus. Essentially, natural fertilizer, which creates a lush and healthy river bank. And because some holes are underwater or on the river bank, these tunnels also allow for water to come into the shoreline, helping keep the soil moist in the summer, and helping reduce the destructive energy of floods in the winter. And as is the case with all prolific burrowing species, their burrows are also used by amphibians, reptiles, insects, and other
small mammals. And as I'm sure you'll notice, all of these benefits only arise when there is an abundance of voles, which used to be the case when the UK population stood at around 8 million voles, but due to a combination of urban and agricultural development combined with water pollution and crucially the spread of the invasive mink, the vole population dropped to around 200,000, or about 3% of what it used to be. And in many areas, they actually went extinct, such as here where we have our project. Now, for us to even consider a reintroduction, the conditions needed to be good and the mink needed to be under control, which thankfully has started to become a reality in many places due to
effective eradication programs. However, none were undertaken in Cornwall. So, the mystery remains as to why the mink disappeared, which is something we were curious to ask David, our partner at Cornwall Conservation. There is a theory that otters out competed them in the rivers, but then the mink moved more to land. But then polecats have made a comeback as well, and they've out competed them from that way. So, they've kind of been squeezed. There's There's no niche for them, really. And that's that could well be true. Um but, you know, fingers crossed. It's good news then there's no niche for the mink.
No niche for the mink. Excellent. Now, this is just a theory and David does not let his guard down just because the mink seem to be gone. He keeps on surveying to make sure that they haven't come back. We're not sure if there are mink still available still around in Cornwall, but we can't find any, but we can't take the risk by not surveying for them. Okay. So, now before we go looking for burrows and voles, let's rewind 4 years back to the release. To fund this work, we provided Cornwall Conservation with 14,760 pounds to cover the cost of getting the voles from the breeding center and
releasing them at Charlesback Farm. And when the time came, 135 lucky rodents got a taste of freedom in a new place that used to be an agricultural smallholding and had by then been restored for nature with ponds, wet ditches, a river, and wetland habitat. And being one of the first reintroduction projects in this part of the country following the voles' demise, the public showed a keen interest with local communities joining and even national TV crews turning up for the occasion, which was pretty cool stuff. Then next year to boost a new population early on, we released another 84 voles, which went swimmingly. But now the champagne fizz is long gone, and the BBC or ITV will never bother to follow up on
this story. But the most important question still remains unanswered. Did we succeed? Let's start with the place where we released the voles. Trololbeck Farm. We can only release the water voles here at Trololbeck Farm because the charity that runs it and owns it created this habitat. It was converted from a normal field to this beautiful wetland you see behind me, which is a home to all sorts of animals. This high-quality environment was a prerequisite to any release, to have a core of suitable habitat where we knew they would thrive, and where the results can now be reliably monitored, which is why David has deployed a series of rafts
here, which allow him to check for both mink and water vole droppings. And thankfully, we have only seen the latter. In addition to that, we can also look for the burrows and the latrines of the voles themselves to help us assess how many have actually settled here. Now, to be clear, this is not a population survey. It is more of a ballpark estimate, but it is more than sufficient to determine how things are going, whether the population is growing and spreading. And it's a much more cost-effective way of doing it than doing a full population survey. So, based on this, David has estimated that around 80 voles have made their home here in the core area. But from here, they have spread both up and downstream
as well. And David has done some more estimates in those places. Upstream, he found very few burrows, but they were present, maybe less than 10 voles in total. Then downstream in this wetland here, he estimated around 80 voles more. Further downstream in this part here, he found another 40 voles nicely settled in with another 30 settling down over here. And besides these field signs, we also have the results from the camera traps, which you have been seeing throughout this video. And I think it's always nice to have because it is really important to see them go about their daily life in these streams doing what they do best, which is of course munching on some vegetation. But unfortunately for them and rather fortunately for us, we also
caught them providing an easy meal to a predator, which as we have established is a really important function that they provide. So, it is pretty cool to see. And as time has passed, they have continued to spread further and further and can now be found quite far from the original release site. So, we've come to a site that is a fair distance from the site where we released them, but it's about 5 km downstream. And Dave has seen a lot of vole sign here, so we're going to go and see what we can find. This is uh it's just a local amenity area run by a caravan park. Um and they've got this really lovely stretch of river uh that is one of the last stretches before it goes uh tidal, so um we've discovered that the water voles have
moved down here from the release at Trust Bank. Um it's as the crow flies probably 6 or 7 km, so it's quite a distance. It's taken them uh I think probably 3 years until they've colonized it properly. There was some signs a while before. Um but now we're finding that there's breeding burrows in several different areas, So, yeah, it's really good news. Fantastic. And why do you think they stopped here? Uh I don't think they can go too much further because of where it goes tidal. So, the water uh the um too much salt water is not good for them. Although, I think they can live in brackish water. But, this is probably the last really good area of good
habitat. Yeah. Final frontier of the river. Final frontier. Yeah. So, here at the edge of the territory that they can probably colonize downstream, David counted another 60 voles, give or take, which gets us to a total of about 290. However, this does not account for certain areas David did not have time to survey, particularly along the Kennel River. And of course, this does not include any burrows he was not able to spot or all the ponds and wet ditches that they have surely moved into between this part of the river and the release site. The true population is without a doubt much larger. And with most voles reaching breeding age after 5 weeks, having multiple litters per season, and
an average lifespan of less than 1 year, we can be quite certain that these are no longer the voles we released. In all likelihood, they are the sixth or eighth generation descendants, born in the wild to wild parents who had wild parents themselves, doing what voles are meant to do out here, living fulfilling lives, munching away, and really bringing health back to this river system. And for us, all this evidence is really reassuring that this was the right time to attempt a reintroduction and to try our chances at recovering the species here. I mean, this is a landscape where the vole should without a doubt exist. And to many Britons, water voles are a main character in a traditional
countryside, stirring memories of a rural Britain once abundant with wildlife. And seeing them out there today is a reminder that restoration is possible, and that what has been lost need not be lost forever. And it also really shows the power of what we can do together, and what you can help us do by becoming a Mossy Earth member. You see, we have come a long way since 2022. These days, we have our own teams that run large landscape-level rewilding projects in the degraded rainforest we bought in the Amazon, in the fjords of Scotland, in the coral reefs of Indonesia, and in the Mediterranean cork oak forests
of Portugal. And we also partner with amazing people like David all around the world who are trying to solve something important, ranging from the reconnecting of wetlands in Iceland to the flooding of forests in the Danube, all the way to the study of reforestation solutions using ants and termites in Benin. As a member, you'll be the one making this possible. We don't have huge investors, we are not in debt, we don't run ads or work with any one large company that controls our projects. We are free because of you. And as you can see, we deliver the receipts down the line, whether we succeed or whether we fail and learn from our mistakes. So, we hope that you'll consider joining us to do some rewilding at mossy.earth. The
link is in the description and in a pinned comment down below. Or you can scan this QR code here. Now, after all of this searching and surveying of endless burrows, Lily really wanted to lay her eyes on a water vole. So, together with David, they resorted to some bribery to catch a glimpse of this iconic rodent. And after a bit of waiting, the moment finally came. Well, I'm so happy I saw a water vole in the flesh just munching on some apple just over there. Well, thank you so much for watching.
It's been so nice to come down here to Cornwall and see a project that's done so well. It's been very successful. And thank you so much to our Mossy Earth members who truly make all of this possible. And if you'd like to join us, then please do so at mossy.earth. Until next time. Cheers.
