Ex-situ Wetland Plant Project

As part of Saving Oxford’s Wetland Wildlife, we’re collaborating with Oxford Botanic Garden, local expert botanist Judy Webb and the local community to help bring rare wetland plants back from the brink…

Oxford is a critical area for freshwater biodiversity, and ranks in importance alongside well-known areas such as the Lake District, the Norfolk Broads and the New Forest. The area supports rare and important wetland plant species such as Creeping Marshwort, Fen Violet, Greater Water-parsnip and Water Violet (you can read more about these species here).

However, these species are only just clinging on in the Oxford area, with threats such as pollution, lack of suitable management and climate change posing very serious risks to remaining populations.

Creeping Marshwort is a Critically Endangered wetland plant.

As part of Saving Oxford’s Wetland Wildlife, Freshwater Habitats Trust has been collaborating with Oxford Botanic Garden and local expert Judy Webb to establish an ex-situ wetland plant conservation project. Ex-situ conservation is when species are helped outside of their natural settings – for example in zoos and botanic gardens. We brought rare wetland plants into the botanic garden to grow them on, because they are struggling to survive in their natural environment.

The project involves the cultivation of some of Oxford’s rare wetland plant species, which, once they have reached a large enough size, are planted out at suitable receptor sites around Oxford. This helps to boost populations and, critically, increases the number of sites each species occurs at. This kind of work is vital to prevent these species from going extinct locally, especially in the face of climate change.

Greater Water-parsnip (Sium latifolium) in flower.

So far, Greater Water-parsnip and Creeping Marshwort have been planted out as part of this project. Fen Violet, another endangered plant, was also planted out experimentally as part of an earlier Oxford university project in 2015 on one of our receptor sites, and has, with careful but quite intensive management, survived and set seed. All three species are doing well so far at their receptor sites, which is excellent news.

In summer 2020, we extended the range of receptor sites around Oxford with practical management work funded by TOE, preparing sites around Oxford for the planting out of some Greater Water-parsnip plants. The plants were introduced in August 2020, with the help of Oxford City Council and volunteers. Creeping Marshwort was also planted. More introductions are planned for 2021. 

Project Officer Ellie Mayhew and Carl Whitehead from Oxford City Council planting out Greater Water-parsnip plants.

The ex-situ conservation project was expanded in summer 2020 to include four more species of rare wetland plant: Water Violet, Frogbit, Marsh Stitchwort and Common Bladderwort. Staff at Oxford Botanic Garden are currently working on propagating these plants, and will hopefully have some Marsh Stitchwort and Common Bladderwort ready for planting out in summer 2021. 

Fen Violet (Viola persicifolia) in flower.

The project is also working collaboratively with community groups to set up ‘Species Conservation Hubs’ in Oxford to involve local people with the conservation of Oxford’s wetland plants. The first hub was set up at Boundary Brook Nature Park in September 2020, where 10 Greater Water-parsnip plants are being looked after by volunteers from Oxford Urban Wildlife Group. Signage has been put up around the site to inform visitors about the project.

One of the hub signs at Boundary Brook Nature Park.

Greater Water-parsnip plants at the Boundary Brook Nature Park Species Conservation Hub.

Fen Violet, Creeping Marshwort and Greater Water-parsnip in propagation at Oxford Botanic Garden.