Explanatory table for the species composition and biodiversity tables

Factor Category Definition
Characterising species   A list of those species considered to best characterise the biotope together with associated information on their frequency of occurrence, degree of faithfulness and the typical abundance at which they occur.
% Frequency of occurrence   The species listed include those which are constants (i.e. they occur in >60% of the records for the type) plus those which occur in less than 60% of the records but which are highly faithful or moderately faithful. The symbols represent percentage occurrence in the samples as follows:
  Occurs in 81-100% of the records for the type
  Occurs in 61-80% of the records for the type
  Occurs in 41-60% of the records for the type
  Occurs in 21-40% of the records for the type
  Occurs in 1-20% of the records for the type
Degree of faithfulness   This is indicated by the following guidelines, based on the relevant major habitat and the appropriate level in the classification (i.e. Ascophyllum nodosum may be considered moderately faithful at the biotope level, but highly faithful at the biotope complex level):
  Highly faithful species restricted to this or very closely related types
  Moderately faithful species found in this and other related types in the relevant major habitat
  Poorly faithful species found very widely in the relevant major habitat
Typical abundances   These are given according to the MNCR abundance scales (see Appendix) in Connor et al. (1997a, b) which are the scales used for all MNCR and BioMar field recording for in situ surveys. Sediment infaunal sampling usually yields counts of individuals per sample; these have been converted to the MNCR abundance scale for compatibility of data presentation here. The abundance given is a mean abundance derived from the records assigned to the biotope.

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