Accounting for Nature: Assessing habitats in the UK countryside
6.   Mountain, Moor, Heath and Down

Conclusions and implications

6.36 The major widespread semi-natural Broad Habitats of Acid Grassland, Dwarf Shrub Heath, Fen Marsh and Swamp, Bog, Calcareous Grasslands, Bracken, Montane and Inland Rock extended to an estimated 6.4 million ha in 1998, a quarter of the UK. These are mostly concentrated in the upland Environmental Zones of England and Wales, Scotland and Northern Ireland where they are important resources for biodiversity, outdoor recreation and rough grazing.

6.37 In the 1990s, the stock of Dwarf Shrub Heath and Bracken has varied locally but showed no significant net change for UK as a whole. Bog decreased in Northern Ireland. Acid and Calcareous Grassland Broad Habitats showed declines of 10% and 18%, respectively. Losses of Acid Grassland were greatest in England and Wales and involved transfers to Improved Grassland, Bracken and Fen, Marsh and Swamp. Losses of Calcareous Grassland were mainly to Improved Grassland.

6.38 The Fen, Marsh and Swamp Broad Habitat increased by about 17% for the UK as whole, though there were losses in Northern Ireland. In the uplands of Great Britain, this habitat gained area from Improved and Acid Grasslands. The change appears to be associated with grassland reversion and the expansion of rushes. Fen, Marsh and Swamp includes a number of Priority Habitats and the increase in area may be generally regarded as a benefit for biodiversity, but the transfers with other semi-natural habitats need to be investigated further.

6.39 The ecological quality of some of the more widespread semi-natural habitats has remained stable but others have declined since 1990. In Bog and Dwarf Shrub Heath the characteristic heath and bog vegetation declined and moorland grass increased. Changes in vegetation implied increasing fertility levels. It is uncertain to what extent grazing management and deposition of atmospheric nitrogen are the driving forces of these changes.

6.40 Countryside Survey 2000 shows that soil acidity has decreased since 1978 in acid soils most commonly associated with upland environments. Moorland grass mosaics and heath and bog vegetation also showed shifts in the 1990s in favour of plants associated with less acid soils. These new trends suggest a possible reversal of acidification and deserve closer inspection.

6.41 The analysis of the results of CS2000 and NICS2000 for the semi-natural Broad Habitats as a whole suggests that the trends observed from 1990 to 1998 are generally contrary to the objectives and specific targets to maintain and enhance these habitats, as set out in the Biodiversity Action Plan. This is perhaps not surprising, as it is the concern about the losses in extent and quality of these habitats in recent decades that have stimulated the UK Biodiversity Group to develop action plans for the Priority Habitats. The first habitat action plans were published in 1995 but the full set, including the extensive upland habitats primarily considered here, were not published until 1999. The targets for restoration of Priority Habitats are set for 5 to 15 years hence (Box 6.1). The results of CS2000 help to clarify the scale and nature of the problems and emphasise the need for concerted action.