North Wales river among the best in the UK for rare plants

Nation Cymru staff

Important river plant life is thriving in a north Wales river, according to a new report.

All five locations assessed on the Afon Gwyrfai near Caernarfon support healthy and diverse plant communities, with large submerged beds of varied plant species.

This comes from a new study by Natural Resources Wales (NRW), which examined plant communities in the Afon Gwyrfai and Llyn Cwellyn Special Area of Conservation (SAC).

Floating water plantain, a rare and protected species of international importance, was found at each survey location and meets its protected site population targets.

In one location, plants were recorded producing seed. This is rarely seen in Britain and is a strong indicator of a healthy, self‑sustaining population.

Some of these seeds were collected to contribute to the Millennium Seed Bank at Kew Gardens, helping to safeguard the species for the future.

The study focused on aquatic plant communities that are typical of clean, nutrient‑poor rivers. These include groups such as water crowfoots, water‑starworts and milfoils.

The river also supports a range of mosses and other water plants that are important for the river ecosystem.

Francesca Sanchez, report co-author and NRW Specialist Advisor for Freshwater Habitat and Species, said: “This is a strong result. The findings show that the Afon Gwyrfai remains one of the best examples in the UK for this kind of plant community.

“They play a vital role in supporting the river’s health by providing essential habitat for fish, invertebrates and other wildlife, which helps to sustain biodiversity.

“They also contribute to improving water quality by absorbing nutrients, trapping sediments and stabilising riverbeds.”

One survey location showed early signs of pressure. The surveyor recorded higher levels of filamentous algae, which could be linked to increased nutrients in the water.

While the site still meets its targets for plant communities, it has been identified as at risk and will be investigated further. NRW has a dedicated project that is already working to maintain and improve water quality in the Gwyrfai.

The study will be one element of a comprehensive condition assessment of the Afon Gwyrfai and Llyn Cwellyn SAC. Condition assessments provide a comprehensive understanding of the health of SACs and guide ongoing work to protect and improve the most valuable habitats in Wales.