Allendale Moors
Allendale Moors is a Site of Special Scientific Interest in Northumberland, England. The upland moorland ridge site is listed for its heath, flush and upland grassland which provide a habitat for a nationally important assemblage of moorland breeding birds.
Location and natural features
Allendale Moors is situated in the north-east of England, east of Alston and west of Allenheads, and between East and West Allen Dales – tributaries of the River Allen – and Nent Dale and Upper Weardale; all found in the south-west of the Northumberland. The u-shaped site, which excludes the valley of the West River Allen from Carrshield northwards, is some north to south, and east to west. It is at the northern extent and part of the North Pennines, itself designated as an Area of Outstanding Natural Beauty, and it borders three other SSSI, Whitfield Moor, Plenmeller and Ashholme Commons, High Knock Shield Meadow and White Ridge Meadow, and it overlaps Hartley Cleugh SSSI. Hexhamshire Moors SSSI is immediately to the east, separated by the valley of the River East Allen.The site is composed of upland moorland ridges and plateau, above a number of north to south falling watercourses – between the River Nent to the west and slightly eastwards, the River West Allen; and then between the River West Allen and the River East Allen. The site is at elevations from circa along the northerly boundaries, to circa and above on the southern boundary. The terrain is one of the most extensive blanket mires in the north of England, and provides a variety of heath, flush and upland grassland habitats for moorland breeding birds. Underlying the mire is Carboniferous limestone, with abundant lichen-rich outcrops. More generally, Allendale is part of a mineral rich area – the North Pennine Orefield – long-mined and thus littered with spoil heaps of varying ages and states of revegetation, affected by heavy metal contamination, particularly from zinc and lead, and supporting metal tolerant plants such as spring sandwort.
Vegetation
The moorland has a number of distinct vegetative zones. The plateau is dominated by heather and hare's-tail cottongrass with local patches of cross-leaved heath. Other notable species include deergrass, crowberry round-leaved sundew and bog mosses such as and.Dry heath and acid grassland is found on peripheral areas of the plateau, the former supporting heather, wavy hair - grass and bilberry, and with heath rush dominating the latter, with mat-grass, wavy hair-grass tormentil, and heath bedstraw.
The moor has numerous areas of acidic flush characterised by an abundance of soft-rush, bog moss and star-moss. There are also a smaller number of species-rich flushes supporting sharp-flowered rush, common sedge, star sedge, marsh bedstraw, lesser spearwort and marsh violet.
Great Limestone outcrops support rich lichen communities, including elm gyalecta, a rare and endanged species, and a number of other species rare in Northumberland.