Micheline Sheehy Skeffington

Conservation implications of land use practices on the plant and carabid beetle communities of two turloughs in Co. Galway, Ireland

Turloughs, which are unique to Ireland and are priority habitats under the European Habitats Directive, are seasonally flooded depressions found predominantly in the west of Ireland. In 1999, adjacent fields with different stocking densities were selected within two turloughs and plant/carabid beetle communities investigated using releves and pitfall traps, respectively. Overall a positive relationship between % soil moisture and plant/carabid species richness was detected and there was a negative correlation between % cover of bare ground (caused by poaching) and carabid species richness. In one turlough, the number of ruderal plant species was markedly higher in the field where the stocking density was more than twice that of the adjacent field. The results suggest that, while edaphic factors (such as soil moisture) play a role in determining the plant/carabid communities of the turloughs, high stocking levels, which cause excessive poaching, are likely to seriously affect both communities.

The Rise and Fall of Turlough Typologies: A Call for a Continuum Concept

Turloughs are seasonal ground-water-dependent wetlands that occur in the karst landscape of western Ireland. Various typologies based on between-site variation have been applied to turloughs. However valid in understanding turlough functioning, these typologies are difficult to relate to one another, tend to overlook within-site variation, and do not address management issues affecting these priority habitats of the European Union. Furthermore, typologies have not fully utilized available data and lack the comprehensive perspective needed to capture processes driving turlough ecology. We used unpublished and published data on a per-turlough basis to explore the main variables affecting turlough ecology in Ireland. Multivariate analysis shows that turloughs do not split into distinct types; rather, there is one continuum from dry to wet sites, which affects all aspects of turlough ecology. This dry-wet continuum arises from various degrees of karstification of the underlying and surrounding bedrock, which in turn leads to different water inputs, water chemistries, and different deposits on the turlough floor. Few turloughs can be considered as truly dry or wet; most are intermediate or dry-wet mosaics. Turloughs or parts of turloughs at extremes of the dry-wet continuum need different protection measures to prevent water pollution, manage summer grazing, or maintain the hydrologic regime. Although turlough typologies seem logical and straightforward in theory, in practice, typing turloughs is difficult. Trying to fit turloughs within typologies that are weakly supported by the data on which they are based can lead to problems if inappropriately used. A dry-wet continuum concept not only better fits these same data but also gives scope for a more flexible approach to turlough conservation.

Turlough ground beetle communities: the influence of hydrology and grazing in a complex ecological matrix

Turloughs are groundwater dependent grazed wetlands of conservation importance that occur in limestone depressions in the karst landscape, mostly in the west of Ireland. Data on Carabidae, hydrological regime, soils and management (using grazing exclosures) were collected to assess the effects of both hydrological regime and grazing management on ground beetles of Skealoghan turlough. Distinct ground beetle communities have been found associated with different hydrological regimes with carabid beetle community composition sensitive to both changes in hydrological regime and vegetation structure. The hydrological regime is the primary factor controlling the carabid species composition of this grazed wetland. Grazing, particularly selective grazing by animals plays an important but subordinate role to hydrology in providing suitable habitat conditions for many species of conservation importance. This paper provides a detailed assessment of species responses to wetland management and demonstrates the need to maintain a range of hydrological and grazing regimes.

Atlantic floodplain meadows: influence of hydrological gradients and management on sciomyzid (Diptera) assemblages

AbstractMaintaining biodiversity is central to maintaining ecosystem functionality of wetlands. Hydrology has the strongest influence on wetland biodiversity, second to which agriculture is the most influential factor. This study investigates the influence of hydrology and farming practices on the abundance, species richness and composition of dipteran communities on temperate Atlantic floodplain hay meadows. Insects were sampled by sweep-net across twenty-four vegetation zones for which hydrological variables were calculated by combining river level data with fine-scale topographical data. Plant communities were surveyed using relevés and land owners were interviewed to gather data on current and past management regimes. A total of twenty-two sciomyzid species were recorded; over one-third of the Irish fauna. Flood depth and duration were found to have the strongest influence on sciomyzids, syrphids and plants. Sciomyzid species richness and total abundance were both positively correlated with hydroperiod and flood depth while both plants and syrphids responded negatively to increases. The difference in response highlights the need to assess more than one taxonomic group, when assessing the impact of changing environmental variables on biodiversity. Whereas vegetation structure drives changes in sciomyzid indicator species, plant species richness and composition, past management regimes and current nutrient inputs do not appear to influence these species. Thus, while the maintenance of the hydrological heterogeneity and the diversity of mowing regimes is important in maintaining biodiversity, variation in nutrient inputs and previous management (at least within the range here investigated) is likely to be of lesser importance for Syrphidae and Sciomyzidae.

Field Boundary Habitats and their Contribution to the Area of Seminatural Habitats on Lowland Farms In East Galway, Western Ireland

Sustainable agriculture and the provision of environmental public goods are key deliverables for European farming and food production. Farmland biodiversity, cultural landscapes, soil functionality and climate stability are among the environmental public goods provided through agriculture. Future Common Agricultural Policy (CAP) direct payments are intended to be more targeted at the provision of these agricultural deliverables. Field boundaries are an example of such deliverables. They are widespread features that have both environmental and aesthetic functions in farmed landscapes. However, research on their variety, density and contribution to semi-natural habitat cover on farms in Ireland is lacking. This study investigates the diversity and density of all field boundary habitat types on 32 lowland farms in east County Galway, western Ireland. A total of 286km of field boundaries were surveyed across six study sites. Five types of field boundary habitats were recorded. The density of field boundaries on the farms studied was high and could have positive implications for delivery of environmental public goods and sustainable farming metrics. In more intensively farmed areas, field boundaries were the only remaining semi-natural habitat on some farms highlighting the need to retain, and improve the ecological quality, of these features. The condition of one field boundary type (hedgerows) was also investigated in further detail. While the density of field boundaries was high on many of the surveyed farms, we found that the hedgerows on these farms were not necessarily in good condition for wildlife.

Developing a predictive modelling capacity for a climate change-vulnerable blanket bog habitat: Assessing 19611990 baseline relationships

Aim: Understanding the spatial distribution of high priority habitats and developing predictive models using climate and environmental variables to replicate these distributions are desirable conservation goals. The aim of this study was to model and elucidate the contributions of climate and topography to the distribution of a priority blanket bog habitat in Ireland, and to examine how this might inform the development of a climate change predictive capacity for peat-lands in Ireland. Methods: Ten climatic and two topographic variables were recorded for grid cells with a spatial resolution of 1010 km, covering � 87% of the mainland land surface of Ireland. Presence-absence data were matched to these variables and generalised linear models (GLMs) fitted to identify the main climatic and terrain predictor variables for occurrence of the habitat. Candidate predictor variables were screened for collinearity, and the accuracy of the final fitted GLM was evaluated using fourfold cross-validation based on the area under the curve (AUC) derived from a receiver operating characteristic (ROC) plot. The GLM predicted habitat occurrence probability maps were mapped against the actual distributions using GIS techniques. Results: Despite the apparent parsimony of the initial GLM using only climatic variables, further testing indicated collinearity among temperature and precipitation variables for example. Subsequent elimination of the collinear variables and inclusion of elevation data produced an excellent performance based on the AUC scores of the final GLM. Mean annual temperature and total mean annual precipitation in combination with elevation range were the most powerful explanatory variable group among those explored for the presence of blanket bog habitat. Main conclusions: The results confirm that this habitat distribution in general can be modelled well using the non-collinear climatic and terrain variables tested at the grid resolution used. Mapping the GLM-predicted distribution to the observed distribution produced useful results in replicating the projected occurrence of the habitat distribution over an extensive area. The methods developed will usefully inform future climate change predictive modelling for Ireland.

Hydroperiod and Traditional Farming Practices Drive Plant Community Composition on Unregulated Atlantic Floodplain Meadows

The River Shannon, Ireland, among the last unregulated rivers in western Europe, has extensive floodplains and supports rare and endangered species and habitats, of ecological and cultural importance. Unregulated floodplains result in community composition responding directly to natural fluctuations in water level. This study assesses how hydrological factors and farming practices effect flood meadow plant communities. Three main plant communities were identified, forming an uninterrupted ecotone, along a gradient of dry to wet. Habitats of European conservation interest (Lowland Hay Meadows and Molinia Meadows) were well represented. Hydroperiod, calculated using microtopographical measurements, was the primary factor determining community composition and was negatively correlated with elevation and plant species richness. The botanical continuum comprised a range of insect-pollinated species, demonstrating the role of floodplains in providing pollinator services. Climate change projections indicate more prolonged winter flooding in the future, signifying potential range shifts for these plant species and communities; highlighting the need for appropriate conservation measures in the surrounding landscape. Low-intensity farming practices, with minimal fertiliser use and regular hay-mowing, played an essential, secondary role in maintaining plant species diversity. Retaining the floodplain topography, its associated hydrological regime and low-intensity farming practices, are necessary to maintain species diversity and ecosystem services.

Ireland’s Lusitanian heathers – an Erica mackayana perspective

Erica mackayana occurs only in western Ireland and N Spain. In Ireland, where it spreads only by cuttings, it has a very disjunct and localised distribution. Erica tetralix , however, is very common and where Erica mackayana occurs, the hybrid E. x stuartii , is frequent, though never more than 1–2 km from Erica mackayana. The restricted distribution in Ireland of parent and hybrid raises questions as to their origin. Like Erica erigena , Erica mackayana may have been introduced from Spain by traders as packing for goods; the remote location of the sites suggests it may even have arrived with smugglers.

Arctostaphylos heath community ecology in the Burren,Western Ireland

Arctostaphylo-Dryasetum is a rare sub-type of Alpine and Boreal Heath which is known to occur only in Ireland on the limestone karst Burren, in County Clare. Releves were taken across the Burren region and three groups were distinguished: Empetrum nigrum group; Erica cinerea group, Juniperus communis group. Altitude and soil conditions were found to be the main ecological factors responsible for the variation in the data set, especially pH, and the organic and mineral content. Winter grazing appears to maintain this habitat. In some areas Calluna vulgaris has encroached on the rarer plant species cutting trials are underway in an attempt to restore the habitat to good conservation status.