| Summary: | This report presents details of a monitoring survey conducted between 2015 and 2018 to assess the conservation status of the Annex II species Saxifraga hirculus (Marsh Saxifrage) (EU code 1528). The aims of the survey were to assess the species in terms of three parameters: Population, Habitat for the Speciesand Future prospects. Nineteen sites were surveyed, comprising 16 in Co.Mayo and three in Co. Sligo. A review of the previous baseline and monitoring surveys was undertaken as part of the project remit. The assessment criteria were generally found to be suitable. However, following population surveys a number of points were noted: absence of Sagina nodosa did not necessarily signify unfavourable habitat condition, so expert judgement was applied on a site-by-site basis; the general target for vegetation height had been set too low at ≤15cm and was adjusted upwards to ≤20cm; and for water level, or hydrology, to pass, a pass rate of 40% of stops was applied in the current survey, with expert judgement the final decider of whether the site’s overall hydrology was suitable or not. Population extents were determined by extensive walkover surveys and recording GPS waypoints at the outer limits of the population. These points were used to map polygon envelopes in GIS. Assessment data were recorded within monitoring plots measuring 1 m2, which were placed at several locations throughout the population. Count data from monitoring plots were extrapolated up to the population level by multiplying the values in the 1m2 plots by the area in square metres of occupied habitat mapped in GIS. Population was assessed at each site by three criteria: total number of rosettes estimated for the population, density of rosettes (average of counts from 1m2 monitoring plots), and estimated number of flowering heads in the population. Habitat for the Species was assessed by seven criteria: area of S. hirculus (target to match or exceed that measured in the baseline survey), water level, cover of Sagina nodosa (positive indicator ...
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