Irish Semi-natural Grasslands Survey

The Irish Semi-natural Grasslands Survey 2007-2012 by Fionnuala H. O’Neill, James R. Martin, Fiona M. Devaney & Philip M. Perrin is now available. The Executive Summary is reproduced below, and includes summary assessments of the conservation status of priority grassland habitats.

For me, one of the important points is that "A new grassland vegetation classification system based on ISGS relevé data is proposed and presented in detail. This system divides grassland habitats into 19 separate communities. Affinities to existing Irish, British and European classification systems are demonstrated. It is recommended that future grassland surveys in Ireland utilise this classification system for vegetation community description and mapping."

 

 



 

EXECUTIVE SUMMARY

The Irish semi-natural grasslands survey (ISGS) took place between May 2007 and September 2012. The six years of the ISGS resulted in the botanical survey and mapping of 1,192 grassland sites covering 23,188.1 ha of Ireland. A total of 4,544 grassland relevés were recorded. The survey found that wet grassland (GS4 under the Fossitt (2000) habitat classification system) was the most extensive semi-natural habitat, covering 55% of the surveyed area, with highest frequencies seen in western counties. The main management activity carried out in the surveyed grasslands was grazing, with 91% of sites having some form of grazing. The most frequent grazers were cattle, found in 72% of sites. The degree of coincidence between ISGS sites and NPWS conservation sites was examined and it was found that 26% of the area surveyed during the ISGS was within an NHA or pNHA, 20% of the area was within an SAC, and 14% of the area was within an SPA.

The conservation scoring system utilised in this report highlighted the best grassland sites in the country, which are listed in this report. Threat scores identifying sites most at risk from agricultural weeds and agricultural intensification were also calculated.

Five grassland habitats listed in Annex I of the Habitats Directive are described, mapped and assessed: [*]6210 Festuco-Brometalia calcareous grassland (including the priority *orchid-rich variant), *6230 Species-rich Nardus grasslands of upland areas, 6410 Molinia meadows, 6430 Hydrophilous tall herb swamp communities, and 6510 Lowland hay meadows. A total of 1,255 ha of Annex I grassland were surveyed across 324 sites, comprising 5% of the total area of grassland surveyed during the ISGS. [*]6210 was the most extensive Annex I grassland habitat encountered, covering 548 ha; this was followed by 6410 (472 ha). The largest areas of Annex I habitat were recorded in Clare, Donegal and Offaly, with 455 ha of Annex I grassland recorded across these three counties.

The condition of the Annex I habitats was assessed following a rules-based approach using three parameters: area, structure and functions, and future prospects. Overall, a low proportion (7%) of the Annex I habitats had decreased in area since 2000, with area gains recorded in some cases. For the structure and functions assessments, 36% of areas received a Favourable result, with 6410 monitoring stops achieving the lowest pass rate (20%). Structure and functions criteria with the lowest pass rates include forb:graminoid ratio, litter cover and sward height, with insufficient positive indicator species also an issue in some 6510 areas. The future prospects assessment involved examining threats and pressures operating on the Annex I habitats. A total of 64% of sites assessed for their future prospects were in Favourable condition. The most frequent pressures recorded were all related to undermanagement or abandonment (e.g., undergrazing, succession to scrub or heath, bracken encroachment), although issues related to intensification (e.g., fertiliser application, overgrazing, drainage) were also recorded. The overall condition assessment for all five of the Annex I grassland habitats is Unfavourable – Bad. As this survey is considered to be a baseline for the sites surveyed the criteria to assess quality are being compared to the national standards; subsequent monitoring may show that some Annex I grasslands, due to geographic location or other factors, may already have favourable structure and functions within the context of their local ecosystem.

A new grassland vegetation classification system based on ISGS relevé data is proposed and presented in detail. This system divides grassland habitats into 19 separate communities. Affinities to existing Irish, British and European classification systems are demonstrated. It is recommended that future grassland surveys in Ireland utilise this classification system for vegetation community description and mapping.

The results are discussed in the context of recent National Conservation Assessments, the link between the ISGS and high nature value farmland is explored, and ways in which the ISGS helps to inform Irish and EU wildlife legislation are outlined. The report makes recommendations regarding the conservation of grassland sites, particularly those that contain Annex I grassland. Included in the appendices is a list of the criteria used to assess Annex I grassland habitats; a monitoring protocol for the future monitoring of Annex I habitats is also provided, together with guidance on assessing the future prospects of Annex I habitats.