Introduction

Durham enjoys a mixed coastline providing a diversity of habitats, including cliffs, rocky and sandy shoreline, and maritime grassland.

Issues affecting these habitats, and some of the most important species which use these habitats, are often regional and national rather than local. In recognition of this, many coastal habitats and species in the Durham area are also the subject of the North East Marine and Coastal Biodiversity Action Plan. For details of regional plans for these habitats and species visit www.nebiodiversity.org.uk

The following plan highlights three habitats which are of particular local significance and which will benefit from actions by local partners.

Strandline

The Strandline is the line of seaweeds and other debris left stranded on the beach at high water mark. The strandline moves up and down the beach in a fortnightly cycle.

Strandlines provide sheltered, moist conditions for invertebrates from both terrestrial and marine ecosystems. Rotting seaweed provides food for a great variety of animals including sandhoppers, kelp flies, beetles, small crabs and sea-slaters. There are a number of beetles which feed only on sea-soaked wood.

The presence of all these invertebrates provides an important food source for coastal birds (see Coastal Birds Action Plan). Strandline also has a role in supporting specialist and pioneer plant communities and in helping stabilise the foreshore in exposed locations, sometimes leading to sand dune formation.

Coastal soft cliffs and slopes

Maritime soft rock cliffs and slopes are a habitat that, in the past, has been largely neglected. They are widely recognised for their geomorphological interest, but less well known for supporting rich invertebrate assemblages and as a refuge for rare insect species.

In the UK twenty-eight species of insect are only found in this habitat, 22 of which are red data book species. Alongside these restricted species there are at least another 75 species that have an affinity to the habitat.

Key reasons for the importance of this habitat to invertebrates include the historical continuity of bare ground (for hunting and basking), the maintenance of early successional pioneer plant communities, especially as nectar sources for solitary bees and wasps, and local hydrological features such as freshwater seepages.

Soft rock cliffs are also important as refuges for invertebrates, as much of the semi-natural cliff top habitat behind these cliffs and slopes has disappeared in the past to arable farming or building development. At the same time, the loss of this cliff top habitat has reduced foraging areas for insects inhabiting the soft cliffs on slopes below.

Maritime Grassland

The cliff top vegetation in Durham is influenced by its magnesian limestone geology and the maritime influence of sea spray, which extends approximately 500m inland. Where it still exists this fragmented habitat consists of varied communities of calcicolous and mesotrophic species, alongside salt tolerant species such as sea plantain (Plantago maritima) and thrift (Armeria maritima). On the Durham coast the vegetation is also unusual in that species with a northerly distribution such as birds-eye primrose (Primula farinosa) and melancholy thistle (Cirsium heterophyllum), overlap with those of a southerly distribution such as yellow-wort (Blackstonia perfoliata) and pyramidal orchid (Anacamptis pyramidalis).

Local status

Strandline

The strandline is present along the coast, but in places it is sparse and broken. It is better developed and wider between the area north of South Bents up to South Shields. The strandline holds maritime vegetation which is starting to make a comeback along the County Durham coast following the cessation of dumping of colliery waste.

Coastal soft cliffs and slopes

In the Durham BAP area our cliff coastline arises where the magnesian limestone plateau meets the sea. It is below 50m, rarely vertical and capped with glacial till. The exposures vary with the height of the limestone plateau and historic erosion, and range from relatively hard magnesian limestone cliffs such as those at Marsden Bay in South Tyneside, to much softer cliffs such as those at Haliwell Banks in Sunderland.

Coalmining has had a major impact on the coast since the coalfields were first exploited in the 1840s. Liquid waste from six coastal collieries was tipped directly onto the beaches of Durham's coast. The accumulation of spoil at the base of cliffs has meant that natural processes have had less impact on cliffs and their vegetation.

Spoil tipping ceased in 1993 with the closure of the last colliery at Easington. Today the artificial raised beaches of spoil are still evident, but not always obvious to the casual observer. Their effect on the vegetation of cliffs is unknown.

No work has been undertaken to establish the value of cliffs for invertebrates in the Durham BAP area.

Coastal cliffs in the Durham BAP area have locally important populations of slow worm and common lizard.

Maritime grassland

In County Durham almost all of the grasslands behind these cliff communities were ploughed up for arable cultivation by 1960. Tiny fragments remain and are designated as SSSI. Larger fragments occur further north, particularly Harton Downhill and the Leas in South Tyneside, and Roker and Hendon in Sunderland. Harton Downhill SSSI contains a number of rare pants, including perennial flax (Linum perenne).

Current or recent activity

Durham County Council – grassland restoration

Green winged orchid attempts

Beach clean-ups

Threats

•  Inappropriate management of the cliff top habitat:

- Loss of semi-natural vegetation adjacent to soft cliffs reduces foraging areas for soft cliff inhabitants, and reduces seed availability for the recolonisation of bare ground.

- Artificial drainage of land above cliffs disrupts the hydrological regime which provides important freshwater features for some invertebrates.

- Agricultural or amenity practices such as ploughing, reseeding, fertilising, close-mowing, all damage or destroy species rich grassland communities.

•  Coastal defences – Any coastal defence work which defends soft cliffs against erosion will affect the maintenance of bare ground exposures and early successional communities.

•  Coastal squeeze from built development - As cliffs erode, and natural coastal processes change the shape of our coastline, the grasslands which lie behind them are slowly squeezed between the retreating cliffs and the immovable roads and houses behind.

•  Possible acceleration of coastal erosion due to climate change.

•  Increased recreational pressure – dog-walkers, caravan parks and so on, has increased nutrient load in some areas, threatening some species of plant.

•  Litter. Litter on beaches and in the sea is a threat to wildlife. It is estimated that, globally, over a million birds and 100,000 marine mammals and turtles die every year from entanglement, or ingestion of. Results from the MCS Beachwatch litter surveys indicate that, over the past 10 years, beach litter has increased by 80%. When litter is caught up in the strandline it is often seen as unsightly and leads to calls for mechanical beach cleaning.

•  Mechanical beach cleaning removes the strandline, its vegetation and invertebrate communities. It also compacts sand, reducing its aeration for burrowing organisms.

Objectives To raise awareness of the biodiversity importance of soft rock cliffs and their cliff-top habitat. To increase knowledge of the invertebrate communities of soft rock cliffs. To improve management of cliff top habitat, and provide cliff top buffers to link the best sites. To influence planning policy to reduce coastal squeeze on semi-natural grassland communities. To restore maritime grasslands. To improve management of maritime grassland communities. To reduce man-made litter ending up on beaches or in the sea. To help the public understand and welcome the strandline as an essential element of the beach To eliminate mechanical cleaning on all beaches.