3. water dependent habitats and species.
While all organisms require water to sustain life, some habitats and species are specifically water dependent, and these have been identified in Ó Riain et al (2005).
Ó Riain (2005) developed the series of databases on which the Register of Protected Areas is based, in consultation with NPWS.
Register of Protected Areas for water dependent habitats and species
The existing Register of Protected Areas for water dependent habitats and species in the SAC and SPA networks is held by the EPA in the form of pdf maps, and in the form of the WDS_Viewer tool linking to information on the Qualifying Interests of each individual site, held in a series of Access databases. The WDS_Viewer was provided to all RBDs in 2004.
The SAC_Water_Dependency database attached to this guidance is a GIS database which updates the Register of Protected Areas for the SAC network.
The current lists of water dependent habitats, and species (animals other than birds, and plants) adopted by the National Parks and Wildlife Service are included as Appendices 1 and 2 respectively of this guidance. On the basis of the currently available information, only 31 of Ireland’s SACs do not include a Habitats Directive Annex 1 listed water dependent habitat or an Annex 2 listed water dependent species, either as a qualifying interest, or as a noted presence.
3.1. Habitats Directive Annex 1 listed habitats.
Habitats listed in Annex 1 of the Habitats Directive are defined in the Interpretation Manual of European Union Habitats (DG Environment, Nature and Biodiversity). The manual is subject to occasional revision, mainly to take new accession States and their habitats into account. Habitats are defined in the Interpretation Manual with regard to their bio-geographic distribution, origin and abiotic features, as well as to their characteristic plant and animal communities. The corresponding national vegetation classification is also referenced when available, since habitat types may show regional variation in species composition and abundance. Water dependent habitats do not conform with the typologies developed under the Water Framework Directive.
A total of 231 European natural habitat types are listed in Annex 1 of the Habitats Directive, 62 of which occur in Ireland. Forty four of the Annex 1 listed habitats which occur in Ireland were defined as water dependent by Ó Riain (2005) and all of them are currently listed as qualifying interests within the Natura 2000 SAC network in Ireland. Further notes on individual habitats are included below and in Appendix 1. All of these habitats are listed in Appendix 1 of this report, the corresponding Heritage Council (Fossitt, 2000) habitat categories are also listed.
Five primary sources/types of water have been identified by Ó’Riain et al as applying to water dependent habitats:
c - coastal waters
t – transitional waters
s - surface waters (excluding transitional and coastal waters)
g - groundwater
p - precipitation
Habitats fall into broad groupings when the source type of water dependency is taken into account, though it should be noted that many habitats depend on more than one source of water. Six groupings of Habitats Directive Annex 1 listed water dependent habitats, which generally occur in association with each other in terms of landscape, or share a water source dependency, have been drawn up in this report, to facilitate review of the types of water management issues that arise within them. These are:
The occurrence of these groupings as Qualifying Interests within individual SACs are analysed in the SAC_Water_Dependency database (see Appendix 4 for the definition table).
Two water dependent habitats do not associate well within the six groupings and are described separately in section 3.9 below.
Most SAC sites are large complexes that include a number of different water dependent habitats and species, which may depend on different sources of water for their maintenance. For this reason, most SACs, and often the individual areas of water dependent habitats within them, cannot be described as being dependent on a single source/type of water. Some turloughs, which are by definition ground water dependent terrestrial ecosystems, are also associated with surface water river channels, for example Rahasane turlough in the Dunkellin catchment. Other turlough SAC designations also include precipitation dependent bog habitats as Qualifying Interests. Lough Corrib is a lake surface water body, but Lough Corrib SAC also includes rivers, and habitats which are dependent on ground water including turloughs and fens, and wet heath and raised bogs which are precipitation and groundwater dependent; this SAC is listed for a total of 11 water dependent habitats and 9 water dependent species as Qualifying Interests.
For climatic, geologic/geomorphological, and hydrological reasons, most SAC sites in Ireland include water dependent habitats and species as qualifying interests. The current list of SACs is analysed in the attached SAC_Water_Dependency database with regard to the water dependent habitats and species present in each site; and whether they are present as a Qualifying Interest (i.e. their presence at a conservation grade assessed in accordance with the Natura 2000 standard data form Explanatory Notes), or present but not currently listed as a qualifying interest. Satisfactory water quality and hydrological regime are essential factors in such areas; most Annex 1 listed water dependent habitats are naturally oligotrophic (i.e. nutrient poor, and vulnerable to eutrophication, which explains their rarity and the requirement to maintain and/or restore them to favourable conservation status). Many water dependent habitats and species require seasonal variation in ground and/or surface water level, and some, notably the fresh water pearl mussel species, require higher water quality than Salmonid and Drinking Water quality standards and are also extremely vulnerable to silt loading.
Within Ireland, there can be substantial variation in the expression of individual water dependent habitat types. Variations in physical, chemical, climatic, and hydrological factors will tend to produce site-specific communities of plants and animals, which are likely to be further modified by human activities in the locality. It is an objective of the Habitats Directive to maintain the full range of expression of individual habitat types, as a measure contributing to biodiversity9.