Project Context and Study Aims
This report focuses on Biogenic Reefs as part of the UK
Marine SAC Project task 1.1 which is reviewing the sensitivity of selected benthic biotope
complexes. There are a number of organisms in British coastal areas which can form
substantial and often quite solid aggregations (Biogenic Reefs) in areas which
would otherwise be composed predominantly of sediments, or on boulders and rocks in sandy
areas. The most important of these in inshore areas are Sabellaria alveolata, S.
spinulosa, Mytilus edulis, Modiolus modiolus and Serpula vermicularis.
Biogenic reefs were chosen as a target group for study because
collectively they encompass a wide range of attributes and environmental requirements, and
have a number of significant ecological, economic and scientific values. Biogenic reefs
can have a number of important effects on the physical (and probably chemical)
environment: they often stabilise sands, gravels and stones; the shells or tubes of the
organisms themselves provide hard substrata for attachment of sessile organisms; they may
provide a diversity of crevices, surfaces and sediments for colonisation; and accumulated
faeces, pseudofaeces and other sediments may be an important source of food for other
organisms. For these reasons many biogenic reefs have a very rich associated fauna and
flora, which at least in terms of macrofauna is often much richer and more diverse than in
surrounding areas. Moreover, Mytilus is particularly important both as a fishery
and as a source of food for birds.
The audience for this report is typically marine resource managers
working at site level. Therefore, this report summarises existing knowledge of biogenic
reefs with particular emphasis on achieving a greater understanding of the ecological
dynamics and sensitivity of this biotope complex, through the following:
a) examining the fundamental environmental, physical, biological and
ecological features of biogenic reefs;
b) assessing the sensitivity of biogenic reefs to natural phenomena and
c) exploring options for monitoring and research into information gaps
that are relevant to the management of biogenic reef communities in marine SAC areas.
Definition of Biogenic Reefs
Description of Key Species and Physical Characteristics
Links to MNCR Biotope Classification
Relevant Conservation Initiatives