The use of the habitat as a basic unit for conservation implementation in Ireland
By Liam Loftus
1
A habitat is a geographical area that is characterized by specific ecological conditions, structure and processes that physically support the organism or group of organisms that lives there.1 According to Fossitt (2000), habitats form “the basic building blocks of the environment that are inhabited by animals and plants, and which are important as units for site description and conservation management” (pg. 7). Habitats provide refuges for rare and endangered species. With growing pressures, these habitats are becoming scarce or absent throughout Europe and there is a greater need for their protection and management. In an effort to provide sufficient habitats for species at risk, special land areas have been designated for protection under wildlife legislation. In these areas, practices that are potentially harmful to flora and fauna are restricted or prohibited. The most important legislation on nature conservation in Ireland is the Wildlife Act, 1976, the Wildlife (Amendment) Act, 2000 and the European Union Regulations. As the principal national legislation for the protection of wildlife, the Wildlife Act provides protection for rare wild flora and fauna and serves to conserve representative samples of important ecosystems. Specific areas of importance for wildlife may be protected under the Act either as Nature Reserves, Refuges for Fauna, or by the basic designation of Natural Heritage Areas (NHAs).2 At a European level the Habitats Directive (92/43/EEC) and the Birds Directive (79/409/EEC) require the identification and protection of key Special Areas of Conservation (SAC) and Special Protection Areas (SPAs) respectively in all EU member states. These form a network of protected sites across Europe under NATURA 2000. This, in turn, forms part of the Emerald network of Areas of Special Conservation Interest (ASCIs) under the Berne Convention.3 Most terrestrial and freshwater habitats are classified on the basis of vegetation characteristics and “supplemented by references to aspects of the physical environment or management, where this enhances descriptions or distinctions” (Fossitt, 2000, pg. 9). Vegetation is usually easy to observe and record and often serves to reflect the underlying geological, edaphic and 1 From http://inspire-forum.jrc.ec.europa.eu/pg/pages/view/1756/ 2 From http://www.npws.ie/legislationandconventions/irishlaw/wildlifeact1976/ 3 From http://ec.europa.eu/environment/nature/legislation/habitatsdirective/index_en.htm
2
hydrological conditions present at each site. For example, salt marsh habitats occur in a variety of brackish water and marine conditions and are sub-divided into two types, CM1 Lower Salt Marsh and CM2 Upper Salt Marsh, according to the vegetation present in each. Variation depends on the degree of submersion, the intensity of grazing regimes or the salinity of the water or substratum. Lower Salt Marsh is subject to more prolonged submersion by sea water and is characterised by a predominance of halophytes, or salt-tolerant plants, such as Common Saltmarsh-grass (Puccinellia maritima) and glassworts. Thrift (Armeria maritima), Sea Plantain (Plantago maritima) and Sea Arrowgrass (Triglochin maritima) are more prominent in the vegetation further inland. In contrast, Upper Salt Marsh is subjected to less frequent and less prolonged inundation by the sea and consequently its vegetation, such as Lesser Hawkbit (Leontodon taraxacoides) and Marsh Arrowgrass (Triglochin palustris), is more characteristic of freshwater conditions. Distinct changes in vegetation can be used to clearly define specific habitats, however in most cases, the identification and differentiation of habitats is difficult in practice. “Habitats frequently merge or grade from one to another, or form complex mosaics, with the result that a continuum of variation often exists within and between different habitat types” (Fossitt, 2000, pg. 10). Common definitions are needed in order to accurately map certain habitat classes within Europe. Since different definitions can be used by international communities, both national and international systems need to be taken into account.4 Fossitt (2000) believes that ‘a standard classification scheme may help to standardise the collection of data on habitats and assist in their management and conservation’ (pg. 7). In A Guide to Habitats in Ireland, categories are given identifying codes at each level that reflect the names of habitat groups or subgroups. The classification scheme covers natural, semi-natural and artificial habitats of terrestrial, freshwater and marine environments, as well as rural and urban areas. Habitat categories are arranged within a series of ordered groupings to produce a hierarchical framework which is intended to facilitate easy habitat identification and differentiation at a variety of different levels. For example:
4 From http://inspire-forum.jrc.ec.europa.eu/pg/pages/view/1756/
3
11 broad habitat groups are identified at level 1, 30 habitat subgroups at level 2, and 117 separate habitats at level 3. In A Guide to Habitats in Ireland, all Heritage Council classifications are designed to be compatible with EU Annex I habitat classifications. Links with the NATURA 2000 code are indicated throughout the text and in an equivalence table in the Appendix. Where correspondence is not exact the Interpretation Manual of European Union Habitats can be consulted as an external guide. The Annex I habitats listed in the Habitats Directive “support populations of rare or notable species such as those listed in Annex I of the Birds Directive, Annex II and IV of the Habitats Directive, and in the Irish Red Data Books” (Fossitt, 2000, pg. 8-9). In Ireland, there are 60 Annex I habitats that require special conservation measures and, of these, 16 are priority types that are considered to be in danger of disappearance.5 For example:
Fossitt’s Category
=
EU Annex I Habitats (NATURA 2000 code) (*= priority type)
5 J. Fossitt, 2000, A Guide to Habitats in Ireland, pg. 11.
4
Active PB1 Raised Bogs are designated as Active Raised Bogs (7110) in Annex I and highlighted with an asterisk ‘*’. They are considered a priority habitat because their global distribution largely falls within the EU and they are in danger of disappearing. Other habitats may be designated a priority because they support rare assemblages of species. For example, the coastal grassy plains of CD6 Machair have lime-rich soils that support a unique assemblage of both sand dune flora and calcareous grassland. The commonest species present are Red Fescue (Festuca rubra), Ribwort Plantain (Plantago lanceolata), Common Bird’s-foot Trefoil (Lotus corniculatus) and White Clover (Trifolium repens). However, because of its small range and distribution as well as the rarity of its flora species, Machair is listed as a priority habitat in Ireland only.
Fossitt’s Category
=
NATURA 2000 code (*= priority type)
Machair (21A0) is classified in the Annex I Habitats Occurring in Ireland guide (2007), as a complex habitat “resulting partially from grazing and/or rotational cultivation” which indicates a long history of human resource use (pg. 6). Its management and conservation as a habitat therefore, requires some degree of human intervention. Throughout Europe, many semi-natural habitats have been highly modified by past human activity and consequently, appropriate management plans must be specifically designed for the sites that correspond with the ecological requirements of the natural habitat types in Annex I. For example, FL6 Turloughs represent a unique habitat in Ireland since they are often found in basins or depressions within limestone areas. Their seasonal flooding can produce a dense sward of calcium-rich vegetation which provides excellent summer grazing for many bird and animal species. This habitat type requires the maintenance of grazing practices to prevent further degradation or ecological succession. The ephemeral nature of turloughs and their confined distribution in Ireland means that they are listed as a priority habitat on the Annex I list.
5
Since its introduction in 1992, the Habitats Directive, it has become the single most important piece of legislation governing the conservation of biodiversity in Europe. Its principle aim is ‘to achieve and maintain favourable conservation status for all habitats and species which are considered at risk’. As a result, each member state is required under the Directive, to set up a coherent European ecological network of special areas of conservation under the title NATURA 2000,
and to carry out an inventory of habitat
types present.6 Each member state is obliged to report to the European Commission on the status of listed habitats every six years, under Article 17 of the Habitats Directive.7 Habitats are assessed according to a variety of factors such as range, size, function and structure, as well as future prospects. Their overall status is deemed favourable if the natural range of the habitat and the areas it covers within that range is stable or increasing, and if the structure and functions necessary for the long-term maintenance of the habitat are likely to continue to exist for the foreseeable future. The overall status of each habitat is derived from the worst rating. For example: The Status of EU Protected Habitats and Species in Ireland, published in 2008, provides a ‘comprehensive baseline assessment of the status of the habitats and species that Ireland is required to protect under the EU Habitats Directive’ (NPWS, 2008, pg. 1). The report found that only 7% of the habitats examined are in good status, with 46% inadequate and 47% bad.8 The assessments outline the key pressures and threats that habitats face in Ireland, such as drainage, development and road-making, overgrazing and undergrazing, pollution of waters by nutrients or 6 NPWS, 2008, The Status of EU Protected Habitats and Species in Ireland, pg. 3. 7 From http://www.npws.ie/publications/euconservationstatus/ 8 From http://www.npws.ie/publications/euconservationstatus/
6
silt and the introduction of invasive alien species. The overall status of Irish habitats is poor, however, both national and international legislation is in place to provide a suitable framework for the future implementation of conservation and management plans for those habitats most under threat.
7
Bibliography
Alagona, P., 2011, ‘What is habitat?’, Environmental History, Vol. 16, No. 3, pp. 433-8. Ausden, M., 2007, Habitat Management for Conservation: a Handbook of Techniques, Oxford University, Oxford. Bassett, J., 1983, Report on the Conservation of Irish Coastal Sites: Machair in Ireland, Unpublished Report, National Parks and Wildlife Service, Dublin. Battersby, J., 1999, ‘Habitat Fragmentation’, ORYX, Vol. 33, No. 1, pp. 75-76. Burgess, R., 1988, ‘Community Organization – Effects of Landscape Fragmentation’, Canadian Journal of Botany, Vol. 66, No. 12, pp. 2687-90. Csorba, P., 2011, ‘Landscape Ecological Fragmentation’, Life Sciences Series, Vol. 21, No. 2, pp. 429. Dankers, N., 1996, ‘Managing Habitats for Conservation’, Trends in Ecology & Evolution, Vol. 11, No. 1, pp. 38-38. Doyle, C., (ed.), 2005, Ireland’s Native Woodlands: Abstracts from Conference Papers, Woodlands of Ireland, Dublin. Fossitt, J., 2000, A Guide to Habitats in Ireland, The Heritage Council, Dublin. Knight, T.W., & Morris, D.W., 1996, ‘How Many Habitats do Landscapes Contain?’, Ecology, vol. 77, no. 6, pp. 1756-64. Neff, J., 1998, Irish Coastal Habitats: A Study of Impacts on Designated Conservation Areas, The Heritage Council, Ireland. NPWS, 2008, The Status of EU Protected Habitats and Species in Ireland, National Parks and Wildlife Service, Dublin. Read, H.J., & Frater, M., 1999, Woodland Habitats, Routledge, New York. Suchant, R., Baritz, R. & Braunisch, V., 2003, ‘Wildlife Habitat Analysis – a Multidimensional Habitat Management Model’, Journal for Nature Conservation, Vol. 10, No. 4, pp. 253-68. Sutherland, W.J. & Hill, D., 2007, Managing Habitats for Conservation, Cambridge University Press, Cambridge. Theobald, D., Crooks, K. & Norman, J., 2011, ‘Assessing Effects of Land Use on Landscape Connectivity: Loss and Fragmentation of Western U.S. Forests’, Ecological Applications, Vol. 21, No. 7, pp. 2445-58. Wells, T., 1997, ‘Managing Habitats for Conservation’, Biological Conservation, Vol. 80, No. 2, pp. 222. 8