Water Framework Directive Marine Plants Task Team Tools Paper ...

certain species are only present on certain types of shores and many species have
distinct northern and southern limits. Species records from the database were analysed
(excluding those replicate samples from a single site) producing an MDS plot
showing the similarity between shores within different areas of the country (Figure 9).
Figure 9: MDS plot showing the similarities in species composition and
richness between the five countries.
The results indicate that England, Scotland, Wales and the Republic of Ireland show a
higher level of similarity, but Northern Ireland falls out of this grouping. Except for
Northern Ireland most of the sites showed a high level of overlapping within the
clusters which suggests that the species composition and richness for these areas are
similar enough to be combined in the compilation of a reduced species list. However,
on removal of the Northern Ireland data from the analysis a second split between
England/Wales/RoI and Scotland appears (Figure 10). Given these results it was
thought to be more appropriate to compile three separate species lists for NI, Southern
England/Wales/RoI and Scotland/Northern England. Unfortunately some areas have
very limited data available so these lists may have to be refined as new data is input to