This report is a compilation of 22 habitat reviews, covering many of the significant
marine habitats found around the UKs coastline and in particular within the network
of marine Special Areas of Conservation (SACs).
The purpose of these reviews is to provide a technical summary of the key
characteristics of each habitat, to assist in their management and conservation. As such
the reviews are primarily aimed at marine specialists involved in the conservation
management of the habitats, both in the UK and in other European countries.
The information in this report is based upon nine more detailed studies undertaken
through the UK Marine SACs Project and upon the earlier work on habitat classification
provided by JNCCs Marine Nature Conservation Review and BioMar. The reviews were
originally conceived to support the work of OSPAR and in particular to contribute to our
understanding of the ecological functioning of certain marine habitats in the north-east
Atlantic. Recognising their value in underpinning Special Areas of Conservation, the
series of reviews has been extended as part of the UK Marine SACs Project.
The understanding contained in these reviews continues to evolve, both in terms of the
knowledge of the ecology of the features themselves and in the most effective and
practical means of categorising and interpreting this knowledge. The work will continue to
be taken forward through the MarLIN programme.
The 22 habitat reviews in this report provide a summary of key information, contained
in the nine studies noted above and other key references, in terms of more specific
features. The selection of these features and the information presented in the reviews
builds upon the habitat classification system developed for Britain and Ireland under the
EC Life-funded BioMar Project. This system defines and describes seabed habitats
(biotopes) at a variety of hierarchical scales as an aid to the management and
conservation of marine habitats.
Each habitat is described in a standard way, under the following headings:
- Biotope code and name
- Habitat classification
- Biotope description
- Similar biotopes
- Characterising species
- Frequency of occurrence
The reviews presented here provide the following key additional information on each
- A correlation with other national and international classifications
- A description of the ecological role of the habitat or its key component species
- An assessment of the sensitivity of the habitat to various human activities
- An assessment of the present conservation status (degree of threat) of the habitat, its
current level of protection, and an outline of the management measures that are required
to improve its status.
The reviews provide a model for the development of a key information system on
marine habitats, designed to provide essential information to underpin management and
conservation of the marine ecosystem. They have a standard format to assist the user in
quickly locating the relevant information and lead the user to more detailed information
in supporting references if required. This standard approach lends itself to display on
electronic media such as the Internet (some reviews are now available on JNCCs web
site: www.jncc.gov.uk), where inclusion of photographic images or other graphics and
hypertext links can greatly enhance the users ability to access the information. The
categories used in each review are defined below.
The habitats included here are mostly at the habitat complex level in the MNCR BioMar
classification, that is they each comprise a number of more specifically defined biotopes
which occur in broadly similar habitat conditions. In a few cases the habitat reviews are
at a lower level in the classification, for example the habitats dominated by single
species such as mussels, maerl, eelgrass and honeycomb worms.
Layout of the habitat reviews
Each habitat review is laid out in a standard format. The main sources of information,
criteria and terminology used are given below:
The habitat unit described is correlated to the following habitat classifications:
||EUNIS (November 1999 version)
||Davies & Moss (1999)
||Wadden Sea biotope red list
||Von Nordheim, Andersen & Thissen (1996)
|Britain & Ireland
||MNCR BioMar (version 97.06)
||Connor et al. (1997a, b)
||Dauvin et al. (1994)
The habitat description is taken from the MNCR BioMar classification (Connor et al.
The habitat distribution maps are generated from the JNCCs Marine Nature
Conservation Review database, providing information on the known distribution of the
habitat, including all relevant sub-types, at the date given.
Information relating to each habitat is derived from Connor et al.
(1997a, b) and the relevant UK Marine SACs Project review.
The terms used for each of the habitat factors (e.g. moderately strong tidal streams)
are given in a linked document, as defined in Connor et al. (1997a, b).
Species composition and biodiversity
The tables listing characterising species are taken from marine biotopes classification
for Britain and Ireland (Connor et al. 1997a, b). Data on characterising species
not contained within these reports were derived from the JNCCs Marine Nature
Conservation Review database. The tables are explained in a linked document.
Information relating to each habitat is derived mainly from the relevant UK Marine SACs
Sensitivity to human activities
The measures of sensitivity are based on definitions developed for the MarLIN
programme, and assessed using information derived mainly from the relevant UK Marine SACs
Project review. The sensitivity ranks are the maximum likely for each activity assessed
against the benchmarks given (i.e. a given amount of activity over a particular period).
Tyler-Walters & Jackson (2000) describe the MarLIN programmes
methodology, definitions and procedures for assessing sensitivity of habitats and species.
Note: Whilst this methodology is now well advanced, it is likely that both the
methodology and subsequent ratings will need to be modified in the light of their
practical application and as new information becomes available. Also management of human
activities needs to take account of site-specific conditions, such as the local extent and
frequency of the activity, as these will have a strong bearing on whether the activity is
having a significant damaging effect on the habitat.
Conservation and protection
The availability of conservation status information is very limited at present;
assessment criteria are currently being developed by OSPAR, but are subject to change in
the light of their practical application. The status of decline criterion, as
currently defined in the OSPAR Faial criteria (most recent version: IMPACT
99/15/1, Annex 6), has been applied at a UK level. For the Wadden Sea, similar status
criteria (Wadden Sea biotope red list categories: Completely destroyed, threatened by
complete destruction, heavily endangered, endangered, potentially endangered, presumably
not endangered at present) have been used, as defined by Von Nordheim, Andersen &
If the habitat has some specific protected status in the EC Habitats Directive or the
UK Biodiversity Action Plan, the corresponding habitat is given (UK Biodiversity Group
The terms used for each of the habitat factors
Explanatory table for the species composition and biodiversity
Explanatory table for the information given on sensitivity
to human activities
Explanatory notes for information given on the conservation
status of a biotope