My freshwater habitat: Anne Carter, Horseshoe Pond

A rare aquatic fern is just one reason why Northern England Freshwater Project Officer Anne Carter has chosen Horseshoe Pond at Skipwith National Nature Reserve in North Yorkshire for her My Freshwater Habitat blog.

I’ve been visiting Skipwith National Nature Reserve, near York, for many years and Horseshoe Pond is probably my favourite pond on the 270-hectare site. I return as often as I can and it’s special to me because it’s home to a rapidly-declining aquatic fern called Pillwort.

Why do you enjoy spending time at Horseshoe Pond?

Managed by Escrick Park Estate and Natural England, Skipwith National Nature Reserve is a popular destination for walkers and nature-lovers, but not many will know Horseshoe Pond.

Named after its narrow, curved shape, Horseshoe Pond is not next to any of the paths that cross the reserve so isn’t the most accessible pond at Skipwith. I usually come here to check on the progress of the Pillwort and to enjoy a rare moment of tranquility. And, of course, I always take the opportunity to do a spot of dragonfly watching. The pond is great for dragonflies and, as a member of the British Dragonfly Society and Yorkshire Dragonfly Group, this is a big draw for me. 

The pond is surrounded by heathland and woodland, which provides a beautiful setting and helps to create a clean water body. The trampling, grazing and organic dung of free-roaming longhorn cattle and Exmoor ponies supports the site as a high quality habitat for wildlife. The pond also has a large drawdown zone. This is the gradual slope into the pond, which can be wet or dry depending on the time of year and is the most exciting habitat for wildlife.

All of this makes Horseshoe Pond a very interesting waterbody.

For me, it’s not just the natural beauty of the place, or even the unusual wildlife that inhabits it, that makes Horseshoe pond so special. I’ve also enjoyed many fascinating visits here with knowledgeable and passionate volunteers and naturalists. Together, we’re helping to protect Horseshoe Pond and ensure it remains an important habitat for freshwater wildlife.

How did you discover it?

I’ve always had a fascination with ponds and freshwater habitats, so in 2009, following a long career in design, I retrained to work in the conservation sector. For many years I had been a regular visitor to Skipwith, but I didn’t really start get to know it well until, following on from my degree in Countryside Management, I started work as a Project Officer for The Conservation Volunteers in 2013. This gave me the opportunity to lead volunteer work parties in some of the more remote parts of Skipwith.

Since joining Freshwater Habitats Trust in 2015 I’ve been fortunate to work here many times. As part of the Heritage Lottery funded citizen science project, People Ponds and Water, I supported volunteers to monitor water quality and protected species, such as great crested newts, running ID workshops and clean water surveys.  I also work on rare species conservation, including Pillwort and slender pond (mud) snail, which are both on Skipwith National Nature Reserve. I now come here as often as I can both for work and in my spare time.

Can you tell us more about Pillwort at Horseshoe Pond?

 Pillwort is an internationally threatened species that was once thriving at Skipwith National Nature Reserve, but for many years we thought it had been lost completely from the site.

Because it’s extremely sensitive to pollution and only thrives when there are few other plants, Pillwort is seriously declining. The distinctive grass-like plant is the UK’s only native aquatic fern. Its thin, threadlike leaves unfurl as it grows and it can form a bright green carpet over the margins of ponds and lakes. It’s now a Priority Species for conservation in England and Wales, so it’s important that we protect it.

Through our Flagship Ponds project we were able to create new ponds and carry out regular monitoring at Skipwith, including training volunteers to help us identify and record the species. We were aware that the species hadn’t been recorded on the site for many years and indeed it could no longer be found on ‘Pillwort Pond’ which was once carpeted with the plant. We were therefore keen to bring Pillwort back to the reserve through our pond restoration, creation and translocation work.

Word got around that we were on the hunt for Pillwort. Then, in 2017, eagle-eyed local naturalist and Yorkshire Naturalist Union (YNU) member Mike Wilcox spotted Pillwort growing at Horseshoe Pond. This was a very exciting moment and led to my very first visit to this fascinating pond, along with expert ecologist and friend of Freshwater Habitats Trust Martin Hammond. As the pond is very much off the beaten track it initially took a bit of finding and to this day it remains a hidden gem!

In the winter of 2016/2017, as part of the Flagship Ponds project, we created new scrapes close to the original Pillwort Pond with the hope was that Pillwort might colonise naturally. With the rediscovery of the fern at Horseshoe Pond we were now in a good position to translocate plant material without having to source plants from another site. So, in 2019 we transplanted Pillwort from Horseshoe to one of the new the runway scrapes, and after just a few months, it was thriving and putting out runners.

I visit the ponds regularly to check on the Pillwort’s progress and it’s very exciting to see it doing so well. I’m now working with Dr Barry Wright of the Yorkshire Fern Group to develop new ways of monitoring the species, including using drones to carry out aerial surveys.

What are your hopes for Horseshoe Pond?

I am concerned about the impacts of climate change because Pillwort, and other species, might suffer from excessive prolonged drying. So far, annual drying of the pond margins hasn’t adversely affected the Pillwort at Horseshoe Pond and indeed since it was rediscovered the population has expanded each year.

Interestingly, Barry and I have found that the best time to survey the plant is in the dry season as the population in the drawdown zone is clearly visible around the shore line. In wetter weather, when the pond is at full capacity it is actually hard to see as it’s fully submerged.

However, we have seen the loss of Pillwort at another site near York – Pillwort Scrape on Strensall Military Training Area – which appears to have been caused by excessive drying. As this scrape has dried out quite extensively in recent years, more terrestrial plants have taken over, and Pillwort has not been seen there now since 2019. Thankfully this hasn’t been the case at Horseshoe and Barry and I are keen to keep an especially close eye on the Pillwort population on Horseshoe Pond.

It’s been so rewarding to see Pillwort thriving at Skipwith again. Through the monitoring work carried out by Freshwater Habitats Trust, in collaboration with Barry and the Yorkshire Fern Group, we’ve also found more natural populations of Pillwort on Concord Pond. I hope to see Horseshoe and Concord Ponds continue to be a habitat for this rare species and other freshwater wildlife.

Anne Carter works with our Northern team and is part of our Saving Nidderdale’s Priority Ponds project. Her citizen science work also extends into the Brecks area of Norfolk and Suffolk, with the Testing the Water project, which is part of the Heritage Lottery Funded Brecks and Fen Edge Landscape Partnership Scheme. In addition to her ongoing work with Pillwort, she works on the Medicinal Leech Recovery project, to help protect this rare mollusc.