Over half of Britain's plant species are now non-native

Over half of Britain's plant species are now non-native,Of the almost 3,500 British plant species, non-native plants now outnumber native species by 51% to 49%.

Over half of Britain’s plant species are now non-native

More than half of the Britain’s native plants are in decline, while introduced species are thriving.

This is the finding of the Plant Atlas 2020, a new report summarising decades of observations of British flora. It reveals that 53% of native plants, including common species such as heather, have smaller ranges now than they did in the 1950s, with climate change and agriculture driving the turnover.

Conversely, 58% of non-native species now cover a larger area. Some of them have become invasive, with plants such as New Zealand pygmyweed and garden lady’s-mantle spreading rapidly across the country and outcompeting native species.

While the report paints a worrying picture, it’s not too late for British plants. Conservation groups are calling on the government to ensure that planned new farming schemes effectively support threatened species, as well as providing additional protections for biodiverse areas.

Dr Kevin Walker, who co-authored the atlas and is Head of Science at the Botanical Society of Britain and Ireland (BSBI), says, ‘There’s lots we can do to reverse these declines, but the most important are to increase the protection plants receive, extend the habitat available to them, and to place their needs at the very heart of nature conservation.’

‘We also need to ensure that our land, water and soil are managed more sustainably so that plants, and the species which rely upon them for food and shelter, can thrive.’

‘Plant Atlas 2020 provides the evidence we need to do this important work, but we’ll need even more research and monitoring to help better conserve our wild plants and their vitally important habitats in the decades to come.’

Dr Chris Dixon, Curator of British and Irish seed plants at the Museum, adds, ‘While the findings of this report are not particularly surprising, they are no less shocking.’

‘The authors have made use of an impressive quantity of data to make new and interesting analyses that show how many of Britain’s species are declining, even if it might not be immediately apparent on the ground.’

White flowers of New Zealand Pygmyweed — Some non-native species, such as the New Zealand pygmyweed, can become an invasive pest. Image © IanRedding/Shutterstock

The decline of Britain’s native plants

The UK is one of the most nature-depleted nations in Europe. With just over half of its native wildlife intact, its biodiversity intactness ranks within the bottom 10% of countries worldwide.

Much of this biodiversity was lost during the Agricultural and Industrial revolutions between the seventeenth and nineteenth centuries, but it didn’t end then. Unsustainable agriculture continues to be one of the leading causes of biodiversity loss around the world, causing habitat destruction, pollution and soil damage.

Certain habitats have born the brunt of agriculture, such as wildflower meadows, wetlands and peatland. As a result, species like the green-winged orchid, lousewort and sundews are declining as their habitat becomes scarcer.

Even plants that used to thrive on agricultural land, such as corn buttercups, are now in trouble. An estimated 62% of Britain’s 157 archaeophytes, a group of plants which are technically non-native but were introduced thousands of years ago, are also thought to be in decline.

‘A lot of archaeophytes are arable plants that can grow in areas of low intensity agriculture, but this way of farming has really declined in the past century,’ Chris explains. ‘While some farms are reverting to a more environmentally friendly style of agriculture, others are making use of herbicides which make it difficult for these plants to survive.’

The Agricultural and Industrial revolutions also mark the beginnings of modern climate change, with the world having warmed by an average of 1.1⁰C since the 1800s. Some species are spreading into once cold areas as they warm up, while plants which depend on cold weather are feeling the heat.

For instance, the Alpine lady-fern, which in the UK is only found in Scottish mountains, is losing the snow cover it needs to keep its habitat moist.

Introduced plants, such as the Sitka spruce are also limiting the ability of Britain’s habitats to combat climate change. Widely grown for commercial timber, it is the species with the greatest range increase in the past 70 years as it spread out of plantations and into peat- and moorlands.

As it grows, it is altering these endangered habitats and limiting their ability to store carbon.

The yellow flowers of corn buttercup among grass — The corn buttercup is becoming rarer as a result of more intense agriculture. Image © AnnaNel/Shutterstock

What can be done about the decline of Britain’s native plants?

While many of the report’s findings are a cause for concern, they’re not all bad. Some habitats, such as woodlands and coastal environments, have remained remarkably stable since the 1950s.

It also gives a series of recommendations on how plants in decline can be preserved. Top of the list is a call for stronger legal protections for wildlife to tackle urban sprawl, habitat loss and the spread of invasive species.

‘We need to reduce the intensification of agriculture and reduce the amount of construction we do on biodiverse land,’ Chris says. ‘It doesn’t mean an end to building, but we need to think about where we do it from nature’s point of view rather than an economic one.’

The report calls for these areas of high-quality habitat to be extended. This could include the creation of new protected areas to protect the remaining range of threatened species, or restoring land to provide better links between them.

Doing so could provide an opportunity for struggling species to re-establish themselves. The report identifies 10 plants which have been lost from Britain since 1930, and though two are now extinct, there is a chance that the rest can be brought back.

For instance, interrupted brome and York ragwort were two lost species that are now being re-established from preserved seeds. Part of the reason York ragwort was lost is because it was only described as a species in 2003, so no specific efforts were made to save it.

Carrying out more research into the UK’s plants could help find those which have been missed, with 10 new native species described in the new report. The authors hope that an increased emphasis on botany education could help to achieve this.

‘Plants don’t enjoy the same interest as animals, and while there are a few charismatic species they don’t tend to be as appreciated,’ Chris says. ‘We value the plants that we see, but as a society we don’t do enough to nurture and care for them.’

While many of the big decisions on protecting plants will be taken at a national level, there’s still a lot you can do to help species in trouble. Whether it’s calling for more green spaces, or volunteering to help restore a habitat, you can make a difference in your local area.