A new study has found that half of Britain and Ireland’s native plant species have declined in the past two decades. The study, conducted by the Botanical Society of Britain and Ireland (BSBI),
involved thousands of botanists who collected data on changes in the flora of both countries over the past 20 years. The findings have significant implications for native insects and other species that rely on these plants for survival.
The research, which was published in Plant Atlas 2020, revealed that non-native species are now more numerous in the wild than native ones. The study identified agricultural practices and the climate crisis as the main drivers of decline in native plant species. Changes in farming practices, including nitrogen enrichment, habitat degradation, and changes in grazing pressure, have led to the decline of species such as heather and harebell. Additionally, damp meadows have been drained, leading to substantial declines in plants such as devil’s-bit scabious, which is an important food source for rare butterflies.
The study found that ancient arable wildflowers, such as corn marigold, fared worse than other species, with a 62% decline. This is because traditional grasslands have been reseeded or over-fertilised. Climate breakdown has also affected many species, with mountain plants such as alpine lady-fern, alpine speedwell, and snow pearlwort depending on areas where the snow lies late in the spring and summer.
Of the 3,445 different plant species recorded during fieldwork, 1,692 are native to Britain, while 1,753 non-natives were found to have been deliberately or accidentally introduced into the wild by humans. Many of the non-native species originate from gardens and then spread to establish self-sustaining populations. The planting of non-native spruce is degrading peatland habitats, researchers found, and sitka spruce, which regenerates into peatland and moorland, has shown the most significant increase in range of any species recorded.
Craig Bennett, chief executive of The Wildlife Trusts, said that the decline of native plants is “heartbreaking” and has consequences for everyone. “The loss of natural habitats due to modern farming methods over the last 70 years has been an unmitigated disaster for wildflowers and all the species that depend on them including insects, bats, and birds,” he said. He called for urgent action to be taken to tackle the loss, including increasing protection for plants, extending the habitat available to them, and placing their needs at the heart of nature conservation. Bennett also called for the government’s new farm environment schemes to reverse the decline of nature in the agricultural landscape, for increased protection for local wildlife sites, and for the government’s promise to halve nutrient pollution by 2030 to be honoured.
Dr Kevin Walker, BSBI head of science and co-author of Plant Atlas 2020, echoed Bennett’s concerns, stating that while there is a lot that can be done to reverse the declines, the most important actions are to increase protection for plants, extend their habitats, and manage land, water, and soil more sustainably. This, he said, will help plants and the species that rely on them for food and shelter to thrive. Photo by Ryan Hodnett, Wikimedia commons.