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Definition of sea cliffs
The UK Biodiversity Action Plan defines maritime cliffs and slopes as "comprising
sloping to vertical faces on the coastline where a break in slope is formed
by slippage and/or coastal erosion. There appears to be no generally accepted
definition of the minimum height or angle of slope which constitutes a cliff,
but the zone defined as cliff-top should extend landward to at least the limit
of maritime influence (i.e. limit of salt spray deposition), which in some exposed
situations may continue for up to 500 m inland. This may, therefore, encompass
entire islands or headlands, depending on their size. On the seaward side, the
cliff extends to the limit of the supralittoral zone and so includes splash
zone lichens and other species occupying this habitat."
Sea cliffs can also be defined by the processes by which they are formed, namely:
"Sea cliffs develop wherever erosion of the base of the cliff occurs or
where removal of accumulations of debris from above takes place through wave
action. A simple definition of a coastal cliff is, therefore, one which is:
'formed at the junction between the land and the sea where a marked break
in slope is formed by slippage and/or erosion by the sea.' (Doody
2001)."
Erosion is a key component of their development. Upon this rests the development
of the cliffs themselves, their inherent scenic value, a place for wildlife
and for unconsolidated cliffs, the contribution they make to the sediment budget
of the coast. Two basic forms are identified, which are defined by their resistance
to erosion, namely:
- 'Hard';
- 'Soft'.
References
Doody, J.P.
2001.
Coastal Conservation and Management: an Ecological Perspective. Kluwer, Academic Publishers, Boston, USA, 306 pp.
Conservation Biology Series, 13
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