Experts say nitrogen from burning fossil fuels is absorbed by the soil from rain or air, and acts as a fertiliser.
This feeds nettles, hogweed and hemlock which outcompete delicate plants, such as harebells, that need low-nutrient soils.?Botanic charity Plantlife said it was a greater threat than climate change to wild plants, lichen and fungi.?Dr Trevor Dines, of the charity, said: ?Atmospheric nitrogen deposition is silently ravaging our plant communities.?We are force-feeding the natural world a diet of nutrient-rich junk food and it is having a devastating impact.
?Once diverse habitats are becoming monotonous green badlands where only the thugs survive and other more delicate plants are being bullied out of existence.?
He added: ?It is hard to exaggerate what a destructive impact nitrogen deposition is having on our wild flowers and other flora, fungi, and ecosystems more broadly.?Put simply, this report reveals that nitrogen deposition may present a far more immediate threat to semi-natural habitats than even climate change.?As the first flush of warm weather sees the countryside and waysides greening up, all may seem as it should but look more closely and the truth is a little different.
?Nettles, hogweed and hemlock – ?thuggish? species that thrive in soil steeped in excess nitrogen – are drowning out rare and more vulnerable wild plants who can only survive in less nutrient-rich soil.?
One in three of the UK?s wild flowering plants prefer low nutrient soils, but atmospheric nitrogen from emissions from transport, power station, farming and industry is transforming the landscape.?The report said that across the whole of the UK, 63 per cent of habitats are absorbing more nitrogen than they can tolerate.?This rises to 90 per cent of all nitrogen-sensitive habitats in England and Wales such as heathlands, acid grasslands and sand dunes.?Victims include flowering plants such are harebell which is classed as near-threatened in England and bird?s-foot trefoil which supports 160 invertebrates, more than any other herb.?Also threatened are lichens, mosses and soil fungi.
The report was produced by the Plant Link Network backed by groups including the National Trust, the Woodland Trust, the RSPB and the Botanical Society of Britain and Ireland.
It said: ?Nitrogen deposition must be tackled as one of the key threats to our biodiversity, soils and ecosystems.?