Lowland Heathland

Lowland heathland occurs below the upper limit of agricultural enclosure and is generally found below 300 m altitude. It is characterised by a high cover of plants such as heather, bell heather, cross-leaved heath and western gorse (i.e. ‘dwarf shrubs’), on nutrient-poor soils. Lowland heathland can occur as either wet or dry heath and there is often some associated acid or damp grassland. Good-quality heathland can support important assemblages of reptiles, invertebrates, birds, vascular plants, bryophytes and lichens.

Lowland heathland has declined considerably in the UK during the last century. Most losses have been due to agricultural reclamation, although lack of management resulting in scrub and bracken encroachment has become a significant factor in more recent times.

Current status in Carmarthenshire

Lowland heathland is not extensive in Carmarthenshire. Most of this is wet heath, which often occurs in association with marshy grassland. Notable examples occur at Cernydd Carmel, Mynydd Llangyndeyrn and Mynydd Ystyffalau-carn. The majority of lowland dry heath occurs around the upland fringes, just below the limit of enclosure; small scattered stands also occur along the millstone grit ridge in the south of the county. Here it supports birds such as linnet and stonechat; the only other blocks of similar lowland heathland are small areas on the coast at Marros Mountain and Ragwen Point, near Pendine.

Agri-environment agreements operate at various sites with lowland heathland vegetation and it is anticipated that some habitat restoration work will be undertaken through Tir Gofal.

In Carmarthenshire, 12 SSSI contain lowland heathland vegetation.

Current Factors Affecting The Habitat

• Intensive agriculture, including reclamation and overgrazing.
• Abandonment or undergrazing, resulting in poor vegetation structure and scrub and bracken encroachment.
• Uncontrolled burning.
• Loss and fragmentation of habitat through development.

Lowland Meadows

Lowland meadows are characteristic of traditionally managed farmland and are renowned for their colourful flower-rich swards. Often termed unimproved (or semi-natural) neutral grasslands, they typically occur on freely draining and relatively nutrient-poor soils which have not been heavily fertilised. This type of habitat was formerly widespread throughout lowland Britain, but it has declined markedly over recent decades. It is estimated that 97% of England and Wales’ semi-natural grassland was lost between 1930 and 1984. The primary cause of this decline has been changing agricultural practices, particularly the widespread use of artificial inorganic fertilisers. Such fertilisers greatly boost agricultural productivity, but they also result in the rapid conversion of the original grassland to a lush rye-grass dominated sward. As a result, unimproved neutral grassland is now highly fragmented and localised in the UK, with extensive, high-quality examples being particularly scarce.

Unimproved lowland meadows support a wide range of grasses and flowering plants. The bulk of these species are fairly common, but scarcer plants including greater butterfly-orchid, green-winged orchid and wood bitter-vetch may also occur. Lowland meadows can also be important habitats for various invertebrate groups and farmland birds such as skylark. Furthermore it is becoming increasingly recognised that unimproved neutral grassland can support a rich variety of waxcap fungi.

The term lowland meadow tends to include cover grazed pastures as well as hay meadows. Roadside verges, churchyards and recreational areas can include this habitat.

Current status in Carmarthenshire

Thanks to its industrial past, the coalfield area of Carmarthenshire has been less intensively farmed and still supports good concentrations of unimproved neutral grassland. Scattered examples also occur elsewhere in lowland Carmarthenshire, although generally within a more intensive agricultural setting. Management agreements and agri-environment schemes are in operation at some sites.

Carmarthenshire currently has 11 SSSIs which qualify for neutral grassland.

Current Factors Affecting the Habitat

• Agricultural intensification, including ploughing and reseeding, fertiliser and slurry application, as well as a switch from hay-making to silage.
• Overgrazing, leading to nutrient enrichment and poaching; supplementary feeding produces similar results at a more local level.
• Lack of management, resulting in rank growth and ultimately scrub and/or bracken invasion.
• Urban and/or industrial development.

Purple Moor Grass and Rush Pastures (Molinia-Juncus)

Purple moor grass and rush pastures are damp grasslands which occur on poorly drained, usually acidic soils throughout the lowlands and upland fringes of western Britain. They are characteristic of high rainfall areas and therefore have a restricted distribution, both nationally and internationally. Wales is of particular significance for purple moor grass and rush pasture.

Purple moor grass and rush pastures are varied both in terms of their vegetation structure and species composition. Some sites are dominated by purple moor grass, alongside a range of other plants including tormentil, devil’s-bit scabious and various sedges. Other sites are dominated by rushes, especially sharp-flowered rush and soft rush. Often, however, these two types form an intimate mosaic, with patches of tussocky vegetation amongst a shorter grassy sward.

Purple moor grass and rush pastures can support a number of uncommon plant species including whorled caraway, meadow thistle and lesser butterfly orchid. They are also an important habitat for the internationally threatened marsh fritillary butterfly.

Like other grassland types, this habitat is dependent upon grazing or sometimes mowing to maintain the grassland structure. Without such management, the sward soon becomes rank and species-poor and ultimately disappears under invading scrub. Purple moor grass and rush pastures are also susceptible to drainage and agricultural modification; indeed in the past many sites have been lost to intensive agriculture.

Current status in Carmarthenshire

The Amman and Gwendraeth Valleys, both lying on coal-bearing shales and sandstones still retain an a good density of purple moor-grass and rush pasture, much surviving due to patterns of land holdings or physical difficulties of intensive management, which meant the land could not be drained or improved. Further examples are scattered throughout the rest of the county.

Carmarthenshire has inevitably suffered considerable losses of purple moor grass and rush pasture through agricultural intensification and development, especially around the Cross Hands area. Opencast coaling has also destroyed a number of sites on the coalfield. More recently a number of sites have become degraded through neglect and lack of management.

A significant area of purple moor grass and rush pasture is presently covered by Tir Gofal and SSSI management agreements. In the Cross Hands area the Mynydd Mawr Project aims to work with local landowners to improve this habitat for the marsh fritillary butterfly. A project is underway to survey a large area of land to assess the quality of the habitat in the Cross Hands area which will inform future development and allow targeting of sites for potential management.

Carmarthenshire currently has 21 SSSI which qualify for this habitat. Mynydd Mawr SAC is made up of three SSSIs and partly designated for purple moorgrass and rush habitat.

Current Factors Affecting the Habitat

• Agricultural ‘improvement’, including drainage, reseeding, fertiliser application and cultivation.
• Inappropriate management, including overgrazing by sheep.
• Lack of management, resulting in rank growth and ultimately scrub invasion.
• Residential and/or industrial development, as well as road schemes.
• Opencast coaling has also destroyed a number of sites on the south Wales coalfield.

Dry Acid Grassland

Dry acid grassland is scarce in lowland Carmarthenshire, although there are extensive tracts on the upland plateaux  and fringes of Mynydd Du and Mynydd Mallaen. Stands of Sheep’s fescue/Tormentil/Common bent habitat that represent dry acid grassland occur occasionally at lower altitudes, typically confined to free-draining nutrient poor substrates. Generally soils in the Carmarthenshire lowlands are too fertile to support this habitat.

Lowland Calcareous Grassland

Lowland calcareous grassland – grassland occurring over thin calcareous soils - is extremely rare in the county, being confined to a few tiny areas along the thin band of carboniferous limestone which forms the northern rim of the Carmarthenshire coalfield. There has been a long history of quarrying along the outcrop, reducing the extent of this habitat further. The remaining fragments are often very species rich  and characterized by the presence of lime-loving species, including salad burnet Sanguisorba minor, common rock rose Helianthemum nummularium and wild thyme Thymus praecox.