13 Aug 2021

Spreading Bellflower – One of Wales’ Rarest Plants

Ardd Fotaneg · Botanic Garden

I’m Ellyn, the new science placement student based in the Science Centre at the Botanic Garden.

I have been working here three weeks now but have already learnt so much and have been put in charge of planning an important project to survey a very rare British plant, the Spreading Bellflower (Campanula patula), which is in decline in Wales and England.

Here at the Science Centre, the team have been working to contribute to the conservation and long-term survival of endangered plants throughout Wales, using a combination of field research and conservation genetics to inform conservation plans. One plant in particular that is of great concern is the Spreading Bellflower, which is now critically endangered in Wales, and a priority species for conservation. Although widespread throughout most of Europe, in the UK the population is now mostly restricted to the Welsh border area and has very specific habitat requirements. Changes in agricultural practices has likely led to the decline in the abundance and range constriction of the Spreading Bellflower.

Spreading Bellflower
{:en}Spreading bellflower, Campanula patula {:cy}Clychlys ymledol, Campanula patula

Ten years ago, the Science Team undertook the challenge of surveying all remaining populations of Spreading Bellflower in England and Wales, using modern and historical records of the plant. Spreading Bellflower was only found at 22 percent of sites visited, with 19 plants found in Wales and 275 plants found in England. Genetic analysis found an overall loss in the genetic diversity of UK populations over time, indicating that they may be less healthy and less adaptable to environmental changes, further increasing the threat of extinction.

However, all hope is not lost for the Spreading Bellflower, which has been a familiar site in hedgerows and along woodland paths for hundreds of years. An interesting characteristic of this plant is that it has a persistent seed bank, which means that its seeds can stay viable in the soil for many years (more than 40 years in some cases!). This is why the Spreading Bellflower is usually found in habitats that have been disturbed, as the disturbance (such as coppicing, hedging and ditching) brings the seeds to the surface of the soil where they can germinate. As a result, Spreading Bellflower can reappear at sites after long absences if the habitat is disturbed, providing a glimmer of hope for its conservation, if habitats are managed correctly.

This summer, the Science Team are aiming to repeat the survey conducted in 2011, to see how the population has changed over the past 10 years. I have been put in charge of organising site visits to areas around the England-Wales border, and south to Somerset and Surrey. We will be collecting leaf samples from each individual to conduct genetic analysis to get a better idea of how the populations are faring, and the level of inbreeding in isolated populations. We will also be collecting seeds from the one of the few remaining Welsh populations to be safely stored as part of the Millennium Seed Bank.

I am looking forward to begin surveying this rare plant, which I had never seen before working at the Garden. I am especially excited to find out how the populations of the flower has changed over the past 10 years and contributing to conservation efforts which could potentially help save the Spreading Bellflower from extinction in the UK.