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

EXAMPLE:
Details Score
Site Name West Angle, Milford Haven ­
Shore Type
Subhabitat Type
No. of
Subhabitats
Other factors
Predominantly large rock ridges/platforms and
outcrops
Large rockpools and basic rockpools present along
with crevices and some overhangs (4)
Four 4
No apparent presence of sand scour, natural
turbidity or chalk shores
Total score for shore descriptions 18
The shore description then forms part of the rocky shore metric.
It was decided that simply using the total number of species recorded on a single
shore was not sufficient in itself to classify the shore and other algal composition
information would be required to assist with the final classification along with the
shores descriptions. This also fulfils the requirements of the normative definitions to
include some measure of composition. Although composition varies considerably
general measures of composition can be used such as proportions of red, green and
opportunist species.
• Proportions of red and green species – the proportion of red species is known to
increase with increasing environmental quality and in contrast the proportion of
green species increases as the quality of a shore decreases mainly due to an
increased presence of opportunists. The proportions of brown species stay
relatively constant regardless of overall species richness.
• Use of ecological status groups (ESG) – seaweed species can be used to indicate
shifts in the ecosystem from a pristine state (ESG 1 – late successionals or
perennials) to a degraded state (ESG 2 – opportunists or annuals). This is achieved
by using the following measure ESG 1/ESG 2 (Orfanidis et al, 2001).
• Proportion of opportunists including Blidingia sp., Chaetomorpha linum,
Chaetomorpha mediterranea, Enteromorpha sp., Ulva lactuca, Ectocarpus sp.,
Pilayella littoralis, Porphyra leucosticta and Porphyra umbilicalis.
4
4
6