A methodology has been developed to identify areas of high plant diversity in Ireland. Being able to classify farmland as being of High Nature Value, in an objective manner, will allow the distribution of subsidies aimed at environmental protection to be targeted at the most appropriate farms. A proof of principle is presented here, using three counties as examples, and an outline of the next steps required to develop a regional or county scale operational model are identified.
The process identifies tetrads (2km by 2 km squares) of the Irish grid that contain specific plants or combinations of plants that indicate the presence of threatened and legally protected plants, as well as indicators of specific vegetation types. Publicising the areas thus identified data will allow any landowner to discover the areas on Ordnance Survey Landranger maps and discover if their land is eligible under the scheme.
Any landowner has the possibility of opting into the scheme, even if their farm currently falls outside these areas, by identifying the presence of species or habitats on their land. Thus the scheme will neither be exclusive nor prescriptive, but will place a positive emphasis on biodiversity surveys of farmland. Historic occurrences indicating that the species was once present in a tetrad, and that management practices could allow its return, would provide a further incentive for farmers to adopt management practices that restore such habitats.
These areas are not legal site designations but provide a framework for identifying and highlighting the very best sites for plants and vegetation, which can then be used to support national or regional conservation actions and initiatives. (They will also highlight areas to local planning departments where Environmental Assessments may be important in planning decisions.)
The methodology for selection of tetrads has been based upon a preliminary study already carried out for the Flora of County Waterford in 2008 by the National Biodiversity Data Centre . Guidelines have been developed that will ensure consistency and objectivity. The assessments are based on four criteria:-
- The presence of a legally protected species (Flora Protection Order, 1999; Bern Convention; Habitats Directive);
- The presence of a Nationally threatened species (Red Data Book, 1988)
- The presence of 30 or more Axiophytes .
- The presence of a combination of indicator species that identify priority habitats (Annex I ) under the EU Habitats Directive.
Three county examples have been used for a preliminary ‘proof of principle’ analysis. The first (Waterford) has a very large dataset, the second (Leitrim) has an average level of records for the country and the last (Galway) is one of the largest counties and one of the poorest surveyed.
The results of the work to date have proved striking. Utilising a very detailed dataset (Waterford) and a very scanty dataset (Galway) reveals that the methodology and criteria used is very robust in identifying sites of high botanical interest even when records sets vary by two orders of magnitude. Whilst Galway clearly needs more work, the same criteria identified 102 tetrads in the county, which is approximately the same as revealed by a highly detailed dataset. Since species of conservation concern are the main targets of the present methodology, and since data for such species tends to be both more specific and more up to date, the explanation for this anomaly lies in this fact.
The method has proved to be a simple, but precise, means of identifying areas of significant botanical importance in an objective and transparent manner. Analyses for the entire country are now being prepared.