Less productive grasslands are now mainly restricted to the wetter and thinner soils found particularly in the upland margins. Most of these grasslands depend on traditional farming practices and associated low stocking levels. This maintains the low fertility which benefits a diversity of short and slow growing flowering plants.
Historically hedges were planted to define land ownership and break land parcels into manageable areas. They create a patchwork pattern across the landscape often providing a continuous network. Species rich hedgerows traditionally have stone and earthen banks and play a vital role in biodiversity both as an effective food source and a place of shelter for a range of wildlife. Ideally they should be at least 2m wide, trimmed often with a thick base and contain occasional mature trees. From an agricultural perspective hedges prevent the spread of disease by forming a barrier between livestock herds. Linking many habitats together, hedges act as wildlife corridors and provide all year round food and shelter for insects, small mammals and birds like the priority species the yellowhammer.
Woodland and grassland herbs grow abundantly on banks. Rural hedges predominately consist of native hawthorn with hazel, blackthorn and ash while in urban areas non native species are used, often evergreen with flowers and berries as nectar and food sources for wildlife.
This Calcareous grassland is a botanical oasis, consisting of diverse, species rich grasslands which occur on lime-rich soil, most often derived from Carboniferous chalk or limestone (calcareous).
These calcareous grassland habitats were originally created when woodland was cleared. They rely on grazing or cutting to prevent scrub and rank grasses re-colonising. The thin alkaline soils are rich in calcium carbonate but poor in other plant nutrients such as nitrates and phosphates. Water tends to drain away quickly through the porous bedrock leaving soils generally dry. The habitat often makes up a larger parcel of land, merging into wet heath, bog and acid grassland. Characteristic lime loving plants are quite diverse with wild thyme crested hair grass, lady’s bedstraw, mouse-ear hawkweed, fairy flax, glaucous sedge, lady’s mantle and yarrow. Patches along coastal areas will contain harebell and kidney vetch. Shaking in the wind on slender stalks is the dainty, purple seeded, quaking grass.
Purple moor-grass and rush pastures
Wet rushy pasture dominates some parts of the landscape in Northern Ireland. Some areas where wet grassland has not been agriculturally improved, reveals a special grassland habitat called purple moor-grass and rush pasture. Purple moor-grass and rush pasture occurs on poorly drained soils in lowland areas which have high rainfall. This results in the growth of species which are adapted to water logged and wet conditions. They are grasslands which consist mainly of a grass called purple moor-grass and tall rushes, such as the sharp flowered rush. A huge range of flowering plant species can occur in this habitat, a 1m2 area could be home to 30 different species.
Characteristic plant species include devil’s-bit scabious, meadow thistle, glaucous sedge, flea sedge, lesser butterfly orchid, water-mint, ragged robin, marsh pennywort and wild angelica. A low coverage of scrub or dwarf shrubs may also occur. Purple moor-grass and rush pasture may sometimes be referred to as fen meadow or rush pasture. Fen meadow is usually found on shallow peaty soils and rush pasture is usually found on mineral soils.
Despite its barren appearance, limestone pavement is home to a unique range of plants and it creates a stunning landscape. Limestone is a sedimentary rock that was formed by both chemical processes and compaction of the remains of marine life which lived in the warm shallow seas surrounding Ireland millions of years ago. Most Irish limestone is around 360 million years old. Exposed limestone is naturally faulted and cracked. The cracks are known as grykes and the upstanding ‘paving’ blocks are known as clints, giving the appearance of a pavement. Typical woodland species found on limestone pavement include herb robert, wood sorrel and common dog-violet. The high proportion of ferns commonly found is down to the shady, humid conditions in grykes. Hart’s-tounge and brittle bladder fern along with mosses and liverworts are common residents.
Limestone pavement is noted for its diverse range of lime-loving plants such as blue moor - grass and wild thyme. However, in areas where heavy rain has removed lime from the shallow soils, lime hating plants such as heather are able to grow along side the lime-loving plants. Limestone pavement also provides habitat for fauna such as the Irish hare, stoat, common lizard, skylark, wren, wheatear and cuckoo. Grazing has a strong influence on vegetation and plant life. Appropriate grazing keeps the vegetation short, rich in species and allows herbs to flower and set seed.