Decades-long research project reveals devastating decline in flora

A research project that has collected data over the past 20 years has revealed a devastating story about the state of the wild and native plants of Britain and Ireland.

The research was conducted by thousands of botanists from the Botanical Society of Britain and Ireland (BSBI) and has now been published in the Plant Atlas 2020.

Four main trends have emerged since the 1950s:

● 53% of our native plants, such as heather and harebell have declined in Britain due to human impacts, such as agricultural intensification and climate change
● Non-native plant species now outnumber native plant species in the wild – this startling discovery has huge implications for the insects and other species that depend on our native plants
● Many non-native species are benign but some, such as New Zealand pigmyweed and sitka spruce have become invasive, disrupting ecosystem function and outcompeting native species
● Many montane plants have declined due to climate change, whereas some southern species, such as bee orchid have benefited and spread further north.

Plant Atlas 2020 is the most in-depth survey of the British and Irish flora ever undertaken. It builds on two previous Atlas surveys undertaken by the BSBI during the 20th century.

Of the 3,445 different plant species recorded during the fieldwork, 1,692 were native to Britain, while 1,753 non-natives were found that have been either deliberately or accidentally introduced into the wild by humans.

Julia Hanmer, BSBI chief executive, said: “Plant Atlas 2020 presents a powerful and concerning insight into the changing distributions of our wild plants.

More than 30 million plant records of 3,445 species, collected by almost 9,000 botanists, fed into the Atlas project.

The dedication and expertise of our recorders, combined with the in-depth knowledge of scientists at BSBI and the Biological Records Centre (BRC)/UK Centre for Ecology and Hydrology (UKCEH), provides a unique contribution to the evidence base needed to underpin nature recovery and highlights the urgent need for action to ensure that going forwards our wild plants thrive and are valued.”

Many of the habitats our wild plants depend on have been impacted by changes in agriculture since the 1950s. Nitrogen enrichment, habitat degradation and changes in grazing pressure have led to the decline of species such as heather and harebell; damp meadows have been drained, leading to substantial declines in plants such as devil’s-bit scabious; traditional grasslands have been reseeded or over-fertilised and consequently 62% of our ancient arable wildflowers, such as corn marigold, have declined.

The report suggests that climate change is likely to be the ‘primary cause of the declines of some mountain plants such as alpine lady-fern, alpine speedwell and snow pearlwort, which depend on areas where the snow lies late in the spring and summer’.

At the same time, peatland habitats, which the report states will be essential in the fight to combat climate change, are being impacted by species such as sitka spruce, which is able to ‘regenerate into moorlands and peatlands, reducing their ability to sequester carbon’.

Dr Kevin Walker, BSBI head of science and Plant Atlas 2020 co-author, said: “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.”

Craig Bennett, chief executive of The Wildlife Trusts, who helped fund the publication of the report, said: “The decline of our beautiful native plants is heartbreaking and has consequences for us all.

“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.”

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