Guidance Heathland and fens: encroachment of grasses and trees
Index section Heathland and fens: encroachment of grasses and trees
- Heathland: the encroachment of grasses
- Breeding birds: grass and trees are encroaching in heathland
- Butterflies: heathland and raised bog are losing their open character
- Lichens: grass and trees are encroaching in heathland
- The tawny pipit and active dunes
Introduction
Heathland that is not grazed, burnt, mown or subjected to sod-stripping will spontaneously evolve into forest. When the cultivation of heathland ceased in the 1960s, traditional management was not resumed, allowing encroaching scrub to reduce the area of heathland. Trees are continuing to encroach and, as a result of the heavy atmospheric deposition of nitrogen, so are grasses.
The methods most commonly used to suppress the encroachment of trees and grasses on heathland are grazing by sheep or cattle, and sod-stripping.
As a result of the encroachment of grass and trees and also the effects of water draw-down, the numbers of birds and butterflies have plummeted since 1950. This trend has continued in the last 10 years. The species that have declined most are those of the open heathland, such as the wheatear. The characteristic butterflies of wet and dry heathland and raised bog are also declining. Heathland reptiles are faring better: the common viper is not suffering from the grass encroachment.
An important part of the vegetation on the active dunes consists of lichens that are at risk from encroaching grasses. The invasion of grass and trees is also deleterious for the tawny pipit, a species that mostly occurs in active dune areas.
