THE UK's varied countryside is under threat from nitrogen pollution caused by burning fossil fuels and intensive agriculture, scientists have warned.

Well-loved landscapes ranging from upland heaths to sand dunes are losing their variety of plants in the face of increased atmospheric nitrogen, which is causing a drift towards monocultures.

Without further control of nitrogen pollution, once-diverse beauty spots will become all too similar with just a few plant species such as grasses dominating habitats across the countryside, .

A team led by researchers from Manchester Metropolitan University surveyed dozens of locations across the UK representing five different semi-natural habitats - acid grassland, bog, upland heath, lowland heath and sand dunes.

They examined the 135 sites for the variety and extent of mosses, lichens, flowering plants known as forbs, and grasses, and assessed soil, pollution and climate factors.

The research found that as pollution increased, the diversity of species declined, with the variety of plants cut by up to 40 per cent and species such as grasses becoming more dominant.

Nitrogen deposits from the atmosphere were a significant cause of the reduction in the richness of species in the habitats, the scientists said.