Montane heath
Upland heath
Lowland heath

The Mournes contain one of the best-developed areas of heathland in Europe. The vegetation of Dwarf Shrub heaths or heathland is dominated by a variety of different species of heather and other related small shrubs. A variety of different heathland types have developed under the influence of such factors as climate, altitude and soil conditions. Lowland heath tends to occur on acidic granite rocks, over which a layer of shallow peat has developed.

Leaching of soil nutrients and peat formation tend to increase with altitude, reflecting the rise in rainfall. In the uplands two distinctive communities are distinguished by the relative wetness of the soil, Wet heath and Dry heath. The dry heath of the Mourne Mountains is one of the best examples in the UK of this vegetation type. On the highest mountains dwarf shrub heath grades into Montane Heath which contains some plants more normally found in the Artic, such as Dwarf Willow and starry saxifrage

Lowland Heaths have declined as a result of agriculture reclamation, while in the upland grazing, especially by sheep, has become intensification, replacing heather with grass such as the unpalatable mat grass.

Bogs

Bogs are found where peat has accumulated to form a deep layer and cover most of our uplands. Bogs are made of 95-98% water, most of which comes directly from rainfall, which is very poor in the nutrients that plants need to grow. As a result relatively few species live in bogs but the plants and animals that do occur there tend to be very specialised. One of the most important groups of species associated with bogs are the Sphagnum mosses. These play a crucial role in both peat formation and water retention.

There are two main types of bog – raised bog, which occurs in natural depressions in the lowlands, and blanket bog, which is one of the main vegetation types in the uplands.

Raised bogs are so called because they form a shallowly domed profile of deep peat. This can maintain its own water levels, which are thus raised above the surrounding groundwater table. Lackan Bog is a good example of a lowland raised bog and has been designated an A.S.S.I.

Blanket bogs have experienced heavy grazing, as the uplands have become more intensively used for agricultural production.  This favours grazing tolerant species at the expense of others and can lead to erosion of the peat as the vegetation cover is removed.  Most bogs have been cut for peat resulting in the loss of more sensitive species.

Salt marshes support a limited but highly specialised range of plant species such as lax-flowered sea lavender and sea purslane.

Vegetated shingle banks occur at the upper end of the shore along the Mourne coast and are important for several species that are scarce in NI, such as the oyster plant and sea cabbage.

The Mourne area is also rich in marine life. Inter-tidal reefs at Glassdrumman represent the best NI example of this UK priority habitat.

Carlingford Lough has an exceptional range of inter-tidal and sub-tidal habitats found on rocks and a range of sediment types.

A wide variety of invertebrate species occur within the inter-tidal muds.

These are lugworm, rayworm, Oligochatet worms and molluscs such as Maloma baltica.

These are an important food source for a large number of wintering waders. In addition the islands of the Lough internationally important for breeding terns including the rare roseate tern and wintering wildfowl such as light-bellied Brent geese.

Rocky shores occur on the Mourne s Coast at Bloody Bridge, Greencastle and on the shores of carling ford Lough. They are very diverse habitats with characteristic communities associated with different heights on the shore.

Exposed rocky shores are dominated by mussels and barnacles, while sheltered rock pools contain anemones, hermit, pea, shore, edible and porcelain crabs, shrimps, small fish and starfish to name a few.

Sub-tidal sand is found in Dundrum Bay. Typical species here include the sand eel, the burrowing brittle star, the lugworm and sea potato.

Ancient dunes such as those at Murlough National Nature Reserve contain extensive dune heaths with a range of habitats related to their age and their calcium levels.

They are also home to a variety of plants and animals including the European endangered species the Marsh fritillary butterfly. 

Oak woodland

Before the Neolithic farmers, most of Ireland would have been covered by forest.

Since then, woodlands have declined in extent as agriculture has spread with only 6% remaining in Ireland.

NI remains one of the least wooded areas of Europe.

Introduced tree species do very well due to the wet, mild climate. Non-native conifers such as sitka spruce, Norway spruce and lodge pole pine do very well, however, they tend to be less valuable than native trees for wildlife.

The lowlands and upland margins in the area contain some important oak woodland, rivers and fens. Priority species include the red squirrel, which is being replaced by the introduced grey squirrel.

The most extensive patches of old woodland have been preserved in the demesnes of Rostrevor, Mourne Park, Donard wood and Tollymore.

There are a few broad-leaved woods such as the oak wood in Rostrevor. This mature wood has native shrub and ground layers growing beneath the tree canopy.

These combine to provide additional niches for wildlife, increasing the biodiversity in that area.

Species Rich Hedgerows

Hedges and are characteristic of the traditional Mourne farming landscape.  Because of the well developed network of small fields, boundary features make a significant contribution to biodiversity within Mourne A.O.N.B. hedgerows are often dominated by hawthorn, but other species such as hawthorn and gorse can also be important. The structure of the hedge can be crucially important as a dense, broad hedge is of much more value than a sparce one with gaps. Hedgerow trees, such as ash, create additional diversity providing food and perches for birds.

Hedges can be valuable as wildlife corridors, often providing the only linkages between semi-natural habitats in intensively farmed lowland areas.

The Mourne Biodiversity Audit has been carried out and below is a list of the priority habitats chosen for action in Mourne.

UPLAND HABITATS
Upland Heath
Montane Heath
Blanket Bog

LOWLAND/FARM LAND HABITATS
Lowland heath
Species rich hedgerows
Lowland meadows
Lowland dry acid grassland
Purple moor grass and rich pastures
Fens
Gardens and urban areas

COASTAL HABITATS
Maritime cliffs and slopes
Coastal vegetated shingle
Coastal sand dunes
Coastal saltmarsh
Mudflats
Seagrass beds

www.ehsni.gov.uk/natural/biodiversity/priority habitats.shtml