Identification of priority areas

There is a tendency of cells with similar cell conservation values and of the priority areas to cluster together indicating that the same types of habitats are being selected on multiple occasions though this would require further investigation to determine it this is true. This does not conflict with the goal of the scoring method to identify all areas of high value but it does indicate a level of redundancy, where replicated instances of the same feature occurs within a collection of areas (Hooker et al., 2011). This is a direct result of the lack of consideration for complementarity within all scoring methods of spatial prioritisation (Arponen et al., 2005), and highlights the importance of all of the high value cells in an area. The clustering or association of priority areas with particular habitats may also indicate that some habitats (e.g. coastal areas or a lake) may have had influence over the priority area selection. Alternatively the

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scoring method could be selecting from the highest value areas from amongst the limited types of habitat within each study area. Further research would be needed to understand the representation of habitat and landscapes within the priority areas. Where priority areas coincide with designated sites at the tetrad scale there may be a mix of habitats despite some habitats featuring more than others, for example habitats associated with the designated areas in Fermanagh and Waterford: freshwater, woodland, blanket bog, wet heath, and upland areas in Fermanagh and river, estuary, coastal, and upland areas in Waterford (Figure 3.4). Each cell is likely to contain a mosaic of habitats given the 2km x2km scale and it is not possible to identify if it is the collective habitats or individual sites that are driving high conservation values. The coincidence of the priority areas with designated sites could mean that the designated area network is an important factor in the conservation of plant species. This would be at odds with reports in the conservation literature that found that while globally protected areas are safeguarding species from threatening processes (Gaston et al., 2006), studies at finer scales have highlighted instances where protected areas are not effective (Barber et al., 2012; Devictor et al., 2007; Liu et al., 2001).

An effort has been made to apply the IPA selection procedure at the local scale for tetrads in Co. Waterford (Green & Fitzpatrick 2008). This criteria-based method used thresholds such as the presence of Flora Protection Order species, species indicating important habitats, and species of interest as determined by expert opinion. Of the IPA cells, 75% occur within the top 20% of cell conservation values and the remainder occur within the top 60% of values (Figure 3.5). The priority areas identified using the cell conservation values and piecewise-regression agree at least in part with the identified local IPA and coincide with 47% of the IPA cells (Figure 3.5).

Spatial prioritisation methods seek to identify sets of sites that best meet conservation goals and to allow the targeting of conservation measures to appropriate areas (Kukkala & Moilanen 2013). A methodology already exists for the identification of areas of the highest botanical importance in the form of the

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Important Plant Area (IPA) programme. However, the selection criteria in the UK IPA identification process uses globally threatened, EU threatened, endemic and near endemic species (Plantlife 2015a) that place focus on global and regional scale priority areas rather than on local or national sites. Only four sites met the criteria for IPAs in Northern Ireland (Plantlife 2015b) and this may indicate that, in the context of Ireland, the criteria for IPA selection may be too strict. The focus of IPA selection criteria on species of global or European importance rather than species of national conservation concern is likely to limit the range of sites suitable for IPAs, especially when Ireland has few true endemic (Rich et al., 2008) or globally threatened vascular plant species.

Grid-based distribution maps such as the hectad and tetrad scale maps generated in this research are not likely to correspond to relevant sites on the ground (Eken et al., 2004) and the priority areas identified using the scoring method could instead highlight broader areas of high conservation value. As with the case of IPAs, the priority areas add to knowledge of the spatial distribution of plant diversity. These priority areas could be used to complement protected areas, IPAs and priority areas for other taxa and included in an overall national conservation strategy.

While some priority areas overlap with protected areas these do not necessarily target protection to plant species, and populations of plant species of conservation concern occur outside of designated areas in Ireland (Walsh et al., 2015). The locations of priority areas could be used to guide conservation measures allowing the targeting of specific features without the need for expanding or designating additional protected areas. This is of particular relevance for Ireland where future agri-environment schemes are expected to provide targeted protection of biodiversity in both the protected and unprotected countryside (DAHG 2011). The identification of priority areas for plant conservation could be further explored by using complementarity based methods to maximise species representation. These methods could incorporate the cell conservation values to identify efficient networks of these areas. Such networks would consist of the minimum number of sites of high conservation

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value that guarantees or maximises species representation. This forms the topic of the next thesis chapter.