The Shropshire Hills AONB is well recognised as holding a concentration of biodiversity, resulting from the varied landscape and relatively low intensity of land management and development. The range of habitats and species found reflects the location of the Shropshire Hills AONB at the interface of different biodiversity zones, and spanning transitions from upland to lowland.
The AONB contains 126 Sites of Special Scientific Interest (SSSIs) including biological features, covering 4,500 ha (5.6% of the AONB). These are complemented by 214 county Wildlife Sites covering a further 6% of the AONB. The Stiperstones and the Hollies is a European Special Area of Conservation (SAC) covering 588ha. The River Clun SAC lies just outside the AONB, but is dependent on activities within it.
Heathland and grassland
Heath and moorland habitats are found in significant blocks on the Long Mynd, Stiperstones and Clee Hills. In the Upper Onny Valley and the Clun Forest, heathland has become fragmented through agricultural improvement and now only survives as vestiges. Species-rich grasslands have also become much reduced in the AONB since the Second World War and generally only remain in situations where farming is marginal. Many of these sites are recognised by the Shropshire Wildlife Trust as Wildlife Sites. Traditionally managed hay meadows are particularly valuable for the plant and invertebrate communities they support, but most of the few remaining are very small in size. Small areas of unimproved acid grassland, valued for invertebrates as well as scarce plants, lichens and bryophytes, are scattered around higher ground in the AONB. The most extensive grasslands within the AONB are improved and semi-improved grasslands. These generally have much lower biodiversity value, especially for plants, but are still important for certain birds.
Coverage in the AONB of all woodland (16.8%) and of ancient semi-natural woodland (2.7%) is above the UK average. Broadleaved woodland is found mostly on steeper ground, often fragmented and in small blocks, though the woodland on Wenlock Edge is continuous over a distance of 20 miles. Riparian woodland, typically composed of Alder and Willow is extensive in length along river valleys, but often very restricted in width, typically confined to a single row of trees along the river bank. Mixed and coniferous woodlands are more extensive and in larger blocks than semi-natural woodland, and are an important biodiversity resource.
Rivers are the principal freshwater habitat, and though the AONB excludes the lower reaches of a number of rivers, the Rivers Teme, Clun, Onny and Corve are very important. Notable species include White-Clawed Crayfish and Freshwater Pearl Mussel. The latter is found in the River Clun just outside the AONB, but is completely dependent on the quality of the river further upstream, and is declining rapidly. Dippers have also declined rapidly over recent years in all the AONB’s rivers. The northern and eastern parts of the AONB drain into the River Severn, a short stretch of which runs through the AONB near the Wrekin.
The condition of Alder along riverbanks and effects of livestock access also have a big effect. Traditional coppicing of Alder for clog making and charcoal production stopped decades ago, and over-mature trees tend to shade out field layer vegetation, which supports invertebrates and in turn fish. Alder is also suffering badly from water-borne Phytophthora disease, and loss of trees leads to bank instability. Unrestricted stock access compounds poor development of bankside vegetation and instability, as well as leading to siltation of gravel beds used by spawning fish.
Larger water bodies and wetlands are not found in the Shropshire Hills, but ponds are important and support species including Great Crested Newt.
The Shropshire Hills are characterised by variety rather than large expanses of the same habitat, and this is reflected in the species found, which include those characteristic of both upland and lowland, and both northern and southern distributions. The area is important in a regional context for upland and farmland birds, including Curlew, Dipper, Snipe and Lapwing, though breeding populations of some of these are down to critically low levels. These species act to some extent as indicators of the health of the environment in general, and as elsewhere, this longer term decline is linked to loss of habitat quality. For some species this appears to be stabilising, but Ring Ouzel have been lost to the area as a breeding species within the last five years. Red Kites are expanding into the area from central Wales.
The Shropshire Hills has one of only seven sites known in the UK for Marsh Flapwort (Jamesoniella undulifolia), a globally vulnerable species. Wenlock Edge and the Clun Valley woodlands are county strongholds for Dormice, a European protected species. Upland plants such as Mountain Pansy are known to have declined significantly. Marsh Gentian is found nowhere else in the West Midlands apart from one site in the Clee Hills. The area is a stronghold of Black Poplar, the distribution of which is now known almost comprehensively. Invertebrates include upland species such as Grayling, Small Pearl-bordered Fritillary, and specialised species associated with veteran trees.
For more information on wildlife in the Shropshire Hills and the rest of the county, visit the website of the Shropshire Biodiversity Partnership at www.naturalshropshire.org.uk