Cliffs - Introduction

Maritime cliffs can be broadly categorised as 'hard cliff' and 'soft cliff'. Hard cliffs are  vertical or steeply sloped, typically formed of hard-weathering rocks such as granite or sandstone. Soft cliffs are often formed of rocks such as shales, or boulder clays, which are less resistant to weathering and more unstable. Soft cliffs can be prone to slumping and landslips, caused by erosion from sea, weather, and percolating groundwater (BRIG, 2008; Lake et al, 2015). In Scotland the majority of cliffs are hard-rock, however there are some soft cliffs formed from glacial deposits. For example, an example of hard cliffs along the East Grampian Coast is Bullers of Buchan (fig. 1) (NatureScot, 2023). Around 4000km of the UK coastline has been classified as 'cliff' with around 2500km of this in Scotland (BRIG, 2008; Jones et al, 2013). This is largely hard cliff, as soft cliff is harder to define and classify with regards to other habitat types. 

Biodiversity:
Cliff vegetation is largely determined by levels of wind and sea-spray exposure, soil type and stablility, climate, and other factors such as grazing. Lichens such as black tar lichen (Hydropunctaria maura) and orange sea lichen (Caloplaca marina) can grow on very exposed or sheer cliffs. Characteristic cliff plants recorded along the East Grampian Coast include thrift  (Armeria maritima), sea campion (Silene uniflora), and common scurvygrass (Cochlearia officinalis). Some rarer butterflies have been recorded along the East Grampian coastal cliff areas on steep slopes, in valleys, and on clifftops including grayling butterfly (Happarchia semele) and northern brown argus butterfly (Aricia artaxerxes) (Butterfly Conservation, n.d. a; n.d. b). Cliffs support thousands of nesting seabirds every year. Breeding colonies on cliffs are formed by common seabird species including guillemot (Uria aalge), razorbill (Alca torda), and kittiwake (Rissa tridactyla).

Ecosystem Services (Jones et al, 2011):
Cliffs can provide a number of ecosystem services, following the four classifications introduced in the Millenium Ecosystem Assessment (2005).

Supporting: Like many habitats, cliffs support primary production, water cycling, soil formation, and nutrient cycling. Cliffs support other coastal margin habitats as a source of sediment.

Provisioning: In some locations in Scotland, cliffs are used for grazing livestock for provisioning of meat. Cliffs are of high importance for providing space for wild species diversity - invertebrates, birds, and plants.

Regulating: A key ecosystem service of cliffs is hazard regulation as a sea-defence, giving protection from erosion, coastal flooding, and storm & wave damage. Cliff-top vegetation is important in preventing surface soil erosion at the coast, thus regulating soil quality.

Cultural: Cliffs are of high importance as a resource for education, public knowledge, and scientific study, as an area for recreation (walking,  climbing, wildlife watching) and wellbeing (exercise, local meaningful space, wilderness). Cliffs are of high aesthetic value, providing inspiration for art and culture.

Conservation Status of 'Maritime Cliffs and Slopes':
UKBAP: Priority Habitat (BRIG, 2007)
Scottish Biodiversity List: Priority Habitat (NatureScot, 2020)
Along the East Grampian Coast there are a number of areas under conservation designations. Bullers of Buchan, Collieston to Whinnyfold Coast, Cove, and Garron Point are all designated a Site of Special Scientific Interest (SSSI) for 'maritime cliff'. In addition, Bullers of Buchan and Collieston to Whinnyfold Coast are designated SSSI for seabird breeding colonies, and Garron Point for northern brown argus butterfly. Buchan Ness is designated a Special Area of Conservation (SAC) for 'vegetated sea cliffs'. Buchan Ness to Collieston and Fowlsheugh cliffs are designated Special Areas for Protection (SPAs) for the seabird assemblage they support such as fulmar, kittiwake, guillemot, and herring gull.