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

More documents

Recommendations

Info

through the lack of consistency that is experienced with algal field sampling (Wells, 2002a). In contrast species richness remains broadly constant, in the absence of environmental alteration, over days, months, seasons and years. This was originally shown by Wilkinson & Tittley (1979) for various shores in the Firth of Forth and proposed as a better measure of seaweed community stability than the detailed listing of actual species present, later found by Wells (2002a). Subsequently it has been shown by Wilkinson that species richness increases with recovery from severe pollution using shores subjected to coal mine waste in Co. Durham (Edwards, 1975). Wells and Wilkinson (2003) confirmed the constancy of species richness on high quality shores using regular surveys in Orkney and have shown the importance of taking account of seasonal variation in establishing a level of species richness for a shore. Therefore the decision was made in July 2002 to concentrate on numerical species richness of intertidal rocky shores as a measure of quality rather than the detailed listing of species present. Numerical species richness is a very basic measure of intertidal algal biodiversity and recent studies have shown small degrees of variation in species richness can occur as a result of natural as well as anthropogenically induced variables between sites. Although different ecological communities do not contain the same number of species (Krebs, 1978), there is a particular range of species richness which can be expected within intertidal communities (Wells, 2002). These expected ranges of algal species richness have been proposed as a means of discriminating between the five WFD quality classes measured by their deviation from reference or high conditions. These ranges of species richness were ascertained through the development of an extensive database incorporating a variety of sites from around the UK and Republic of Ireland and consisting of species records from a number of known sources which fitted set criteria (Figures 1 and 2): 1. Only single occasion samples can be used. Single sampling data mimics what might be found by a scientist on a single monitoring visit. Wells (2002) showed that when a location is sampled on several dates to produce an overall species list for an area, the variation in ephemeral species presence between
dates will result in a larger species total that could reasonably be found by a sampler assessing ecological quality in a single survey. This has been referred to as the cumulative effect. Most published seaweed species lists for a site involve observations over several seasons or years to get the maximum possible list, and may also collate recordings from different collectors at widely different dates. Most published lists are therefore not suitable. 2. We need comprehensive lists that are compiled by authoritative workers. Most single occasion lists compiled by environmental consultants etc. are restricted to the common, easily identifiable species – which is unlikely to enable discrimination between shores of different quality. We recognise that agency workers applying the tool will not have this level of expertise. However it is important that the tool is founded on good science so that the proposed reduced version is scientifically robust. These considerations limited the sources of data to: 1. Surveys by the Marine Plants Task Team 2. British Phycological Society (BPS) Field Meeting reports as published in BPJ (M. Wilkinson, MPTT member, organised and/or attended all such annual meetings from 1969 to their end in 1978 and can attest to the scientific quality and sampling method). 3. Other surveys which will have been sought and considered on an individual basis from published material and grey literature. 4. The Northern Ireland Littoral Survey (NILS) carried out from 1984 to 1988 under the supervision of M. Wilkinson for the DOE (NI) which produced full species lists for about 128 shores in NI (Wilkinson et al, 1988). 5. Emma Wells’ Ph.D. work covering shores in Orkney and the Forth on a regular basis (Wells 2002b). 6. Channel Tunnel surveys compiled during the impact assessment for the effect of spoil disposal on the seashore after the construction of twin railway tunnels. This was completed by the Institute of Offshore Engineering between 1985
Page 1: Water Framework Directive Marine Pl
Page 5 and 6: Figure 2: Sites included within the
Page 7 and 8: fauna and flora and exposed shores
Page 9 and 10: Table 1: Field sampling sheet to re
Page 11 and 12: These different community factors c
Page 13 and 14: All datasets were tested for normal
Page 15 and 16: Table 3: Calculation of ‘deshor
Page 17 and 18: Development of a Reduced Species Li
Page 19 and 20: certain species are only present on
Page 21 and 22: Figure 11: Map of the UK and Republ
Page 23 and 24: Table 4: Species lists for each of
Page 25 and 26: Table 6: Boundaries values for RSL,
Page 27 and 28: The final metric system works on a
Page 29 and 30: Table 10: Final quality status and
Page 31 and 32: EQR Value EQR Value 1.00 0.80 0.60
Page 33 and 34: EQR Value 1.00 0.80 0.60 0.40 0.20

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

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?