s A Field Guide to the British Seaweeds - NMBAQC

INTRODUCTION
The EU Water Framework Directive (WFD) requires water bodies to be classified by
their chemical and ecological status. Macroalgae are one of the biological quality
elements to be used in defining the ecological status of a transitional or coastal water
body. For this particular macroalgae component the directive states that for reference
conditions the taxonomic composition should correspond totally or nearly totally with
undisturbed conditions with all sensitive taxa present. As species richness remains
broadly constant in the absence of environmental alteration this was proposed as an ideal
measure of quality. Therefore, levels of macroalgae species richness would be used to set
an ecological quality standard from which any deviation may be measured and used to
classify water bodies as high, good, moderate and poor.
However, the identification of intertidal seaweed species requires high levels of
taxonomic expertise. Therefore, a tool is being developed that may be used by less
experienced persons to assist with the classification of water bodies. This tool utilises an
alternative means of recording qualitative species data, which is to implement the use of
a reduced species list (RSL) whereby the number of species from the RSL will be in
proportion to total species richness thereby acting as a surrogate. The list is composed of
species (approximately 70) that are most frequently present on a variety of rocky shores
within a set geographical area. Additional measurements have been incorporated using
the RSL including the proportion of green, red and opportunist species and an Ecological
Status Group ratio. The tool also utilises basic shore descriptions to allow for natural
variations to be considered.
The tool aims to fulfil the requirements of the WFD by enabling less experience algal
taxonomist to classify areas of coastline. This guide aims to assist with such a process by
providing detailed descriptions on shore sampling methodologies, examples of key
characteristic from which to identify, a comprehensive yet straight forward algal key and
detailed images on each species within the RSL.
Reduced species list identification guide as required by the Water Framework Directive.
2