Biodiversity of the Nature Reserve
The cretaceous clays and sands that make up the soft rock coastal cliffs from Rock-a-nore to Cliff End support a rich invertebrate fauna and cliff nesting bird population. A diverse mosaic of soft rock cliff habitats can be found from extensive areas of bare ground & early successional vegetation to mature undercliff woodland.
In places where the cliff is steep and actively eroding only landslip debris, bare ground, or very early successional vegetation dominated by colt’s-foot Tussilago farfara, thrift Armeria maritima subsp. maritima, sea carrot Daucus carota subsp. gummifer, and sea-beet Beta vulgaris subsp. maritima occur. At Rock-a-nore hoary stock Matthiola incana can also be found and the rare weevil Lixus scabricollis is common on its food plant sea-beet. The local leaf beetle Chrysolina banksi is also present here. This species is very local in south-east England. At Covehurst the very rare lichen Tornabea scutellifera was once present but this species is now considered extinct although could still occur as much of the cliff-face is inaccessible to lichenologists.
A few dozen pairs of fulmar Fulmarus glacialis and herring gull Larus argentatus nest on cliff ledges as well as smaller numbers of lesser black-backed gull Larus fuscus. Peregrines Falco peregrinus and kestrels Falco tinnunculus breed as well as up to five pairs of black redstart Phoenicurus ochruros. Great cormorants Phalacrocorax carbo once bred regularly but now only breed in small numbers occasionally.
The extensive areas of undercliff range from pioneer communities such as pockets of reedbed to mature woodland. Seepages and trickles have produced large areas of wet mud and shallow pools that support nationally scarce water beetles such as Laccobius atrophilus and Acupalpus falvicollis and the ground beetle Tachys micros. Where the gill streams reach the cliff edge more permanent channels of flowing water form which support the only south- east England population of the rare water beetle Hydraena pygmaea.
The nationally scarce moths Webb’s wainscot Archanara sparganii and reed dagger Simyra albovenosa have been found on the small areas of reedbed and reedmace edged pools.
The dryer areas of undercliff are very rich in invertebrates including grey bush-crickets Platycleis albopunctata and the comb- foot spider Episinus truncatus which can be found amongst tall vegetation, and even a small population of small blue Cupido minimus butterflies which just hang on due to patches of kidney vetch Anthyllis vulneraria along the undercliff at covehurst. A number of nationally rare and scarce bees and wasps have been recorded breeding here but the site is especially important for the large populations of long-horned bee Eucera longicornis and Andrena thoracica, which are both are declining species in Britain and Eucera is now a Priority Species for Conservation in Britain. The undercliff has also produced the last British records of the endangered weevil Lixus angustatus. This species has not been recorded for many years and is now considered not to breed in Britain any more.
Mature woodland has developed on the largest and most stable area of undercliff at Covehurst Bay. Bird’s-nest orchids Neottia nidus-avis can be found here but due to the dangerous unstable ground this woodland sits on it is very inadvisable to look for them. Some interesting bryophytes have been found here including Lophocolea fragrans, which is not found anywhere else in south-east England. In recent years this area has been actively moving again and is now inaccessible.Maritime Heath and Grassland
The small pockets of cliff-top maritime grassland that remain still support populations of the nationally rare weevil Cathormiocerus myrmecophilus, the rare ant mimic ground spider Micaria romana, and the ant mimic jumping spider Myrmyrachne formicaria.
The larger areas of rabbit grazed cliff-top acid grassland support a large population of glow-worms Lampyris noctiluca and minotaur beetles Typhaeus typhoeus. The bee-wolf wasp Philanthus triangulum and many other species of wasp and bees nest in the bare sandy ground here. Amongst the heather the lesser cockroach Ectobius panzeri can be found as well the heather bumblebee Bombus jonellus, a tiny bumblebee that collects heather pollen. Greater broomrape Orobanche rapum- genistae grows erratically on the many patches of gorse scrub and Dartford warblers Sylvia undata have been nesting here in recent years amongst the stonechats Saxicola torquata, yellowhammers Emberiza citrinella and common linnets Carduelis cannabina.
The most significant find amongst the cliff-top grassland, during August 2006, is the first breeding colony of sickle-bearing bush-cricket Phaneroptera falcata to be found in Britain.Semi-natural Neutral Grassland and Meadow
Some large areas of semi-improved neutral meadow still exist on the clifftop and all the old cliff-top arable land has been reverted back to semi-natural grassland mainly to provide a pollen and nectar source for many of the bees that nest on the cliff and undercliff such as Eucera longicornis.
Recently Cepero’s groundhoppers Tetrix ceperoi and Roesel’s bush-cricket Metrioptera roeselii have been found amongst areas of semi- natural grassland within the site.Ancient Gill Woodland
Where springs have cut through the softer clays and sands over millennia steep sided gill woodlands have developed. These are very rich in rare and scarce bryophytes (mosses & liverworts) and diptera (two-winged flies).
These humid, frost-free wooded valleys have acted as refugia for species that require mild humid conditions all year round that are present in the northern and western parts of Britain but are very rare in south-east England. These include the rare liverwort Dumortiera hirsuta found in Fairlight Glen, and the nationally scarce money spider Diplocephalus protuberans that lives in streamside leaf litter in Ecclesbourne Glen.
Other scarce bryophytes found here include Tortula freibergi and Fissidens rivularis. Few orchids have been recorded but violet helleborines Epipactis purpurata can be found growing in Fairlight Glen.
Many scarce diptera have been recorded recently including a number of county firsts. Other interesting invertebrates recorded here include the nationally scarce water beetles, Hydraena nigrita and H.rufipes, the moths’ cloaked carpet Euphyia biangulata and festoon Apoda limacodes and the snail Acicula fusca. Hop Humulus lupulus grows along the woodland edge and beside paths in Ecclesbourne Glen and is probably the source of the adult buttoned snout Hypena rostralis moths recorded at the site, although no larvae have been found.
A population of dormice Muscardinus avellanarius thrive within the woodland, woodland edge and scrub at the site.