Ireland is obliged to undertake surveillance/monitoring (Article 11) of the habitats listed on Annex 1 of the EU Habitats Directive and to report regularly on their conservation status (Article 17). The assessment of conservation status requires an understanding of the distribution, area, structures and functions and the pressures impacting on these habitats. Designing an effective surveillance programme involves monitoring a representative sample of the resource across its natural range.
The first quantitative assessment of the conservation status of the EU Annex I Habitat Juniperus communis formations on heaths or calcareous grassland (EU HD Code 5130) in Ireland based on survey data was commissioned by NPWS in 2008. The field survey between 2008 and 2012 covered 174 sites and Juniper was found in 129 of these (Cooper et al., 2012) giving a calculated national area of juniper of 4,765ha. These sites vary considerably in size (ranging from 0.001 ha to 2,673.7 ha) and have a mean area of 38.1ha.
Of these sites, 51 were assessed to meet the criteria of the Annex I habitat, defined by the Cooper as ‘a discrete area supporting ≥50 individual shrubs’ (Cooper et al., 2012). 50 shrubs has been taken as the minimum threshold below which isolated groups are unlikely to reproduce in any sufficient numbers to bring about recovery without inbreeding depression being a significant risk. Formations in Ireland are mostly associated with lowland dry calcareous and neutral grassland, exposed calcareous rock, dry siliceous heath, exposed siliceous rock and dry calcareous heath. However, formations can also occur on coastal dunes and at higher altitudes.
Cooper et al. (2012) assessed all 51 formations including assessment of shrub number, extent, associated vegetation, pressures and threats, the development of indicators to assess structure & functions and future prospects at each population.
(refer to RFT)