Botany & Plant Science

Managing marginal farmland with high nature value can be a strong source of conflict between farmers and conservationists. In the West of Ireland, marginal farmland is at the heart of Special Areas of Conservation (SACs) designation and turloughs are an example of marginal ...

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.

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.

Izvleček UDC 911.2:556.166(417) Sheehy Skeffington M. J. & Mike Gormally: Turlough: mozaik biološke raznovrstnosti in način gospodarjenja, edinstven za irsko Turlough je sezonsko poplavljeno mokrišče na Irskem in kot prednostni habitat pod EU Direktivo za habitate. Številni turloughi so tudi označeni kot Posebno varstveno področje. Turloughi so običajno poplavljeni pozimi, voda jih zalije skozi požiralnike-estavele, ki se odpirajo v podlagi iz apnenca. če je dežja preveč, se lahko napolnijo z vodo ob kateremkoli letnem času. Skoraj vsi so na plastovitem karbonskem apnencu. Ker so te plitve kotanje ali turloghi običajno porasli, medtem ko stalna vodna telesa niso, so izvrstna pasišča in krmišča za prezimujoče vodne ptice, kot so race, gosi in labodi, katerih število je mednarodno pomembno. Skoraj vsi turloughi so v poletnih mesecih pašniki za živino, a le v okviru ekstenzivne reje, saj so obrobnega pomena in velik del leta nedostopni. Rastlinstvo je v veliki meri odvisno od poplavnega režima in tipa prsti; v glavnem gre za skupnost malega šaša ali za travnike. Način gospodarjenja je zelo različen, ne le med posameznimi turloughi, ampak tudi na posameznem turloughu. Zaradi tega so nastali zelo različni travniki, tako po sestavi kot po strukturi, kar pospešuje tako rastlinsko raznovrstnost kot tudi raznovrstnost nevretenčarjev. Medtem ko je bilo osuševanje nekdaj največja nevarnost za turloughe, postaja danes najpomembnejša evtrofikacija poplavne vode. Vendar pa bo v bodoče največja grožnja biološki raznovrstnosti teh kotanj prenehanje njihove izrabe v kmetijske namene. Turloughi so sestavni del irske kulturne pokrajine in je torej pomembno določiti ukrepe za njihovo ohranitev, ki bodo vključevali lastnike zemlje in upoštevali tako družbenoekonomske dejavnike kot tudi ohranjanje njihove biološke raznovrstnosti.

Question: Can GIS and GPS technology be used to quantify the hydrological regime of different plant communities on turloughs (groundwater dependent calcareous wetlands)? Location: Skealoghan turlough, County Mayo, Ireland. Methods: Plant communities were mapped and digitised with GIS software and a digital elevation model of the site was constructed from differential GPS data. Together with records of water level fluctuations on the site from May 2001 to May 2004, these data were used to calculate hydrological variables for each plant community. Hierarchical cluster analysis was used to identify groups of plant communities with similar hydrological regimes. Results: 15 plant communities were mapped at Skea loghan, with the Cirsio-Molinietum and Ranunculo-Potentilletum anserinae being the dominant phytosociological associations. Skealoghan is subject to large temporal and spatial variation in its hydrological regime and fluctuations in water level are intrinsically linked to rainfall. The spatial variation in flooding can be linked to the vegetation zones. Conclusions: GIS and DGPS technology can be used to quantify the hydrological regime of different plant communities on turloughs. Since the hydrological regime is a major environmental factor controlling the vegetation composition of the site, the maintenance of natural flooding regimes is a vital component for the conservation and management of the diverse vegetation mosaic at Skealoghan turlough.

What is the influence of hydrological regime, soils and management on the plant community composition and species richness of Skealoghan turlough (groundwater dependent calcareous wetland). Location: Skealoghan turlough, County Mayo, Ireland. Methods: Percentage cover of vascular plants and bryophytes were recorded, and data on hydrological regimes, soils and management were collected. Data were analysed using multivariate statistical techniques. Results: A total of 69 species of vascular plants and mosses were recorded. Cluster analysis grouped the samples into two separate communities, the Cirsio-Molinietum and the Ranunculo-Potentilletum anserinae plant communities. The plant community composition and species richness followed a main gradient down into the turlough basin, but also varied with microtopography, resulting in a mosaic of vegetation types. Conclusions: The biodiversity and conservation value of the site is linked to the heterogeneity in its physical environment in which hydrology, soils and grazing management all play critical roles.

Turloughs are seasonal wetlands in Ireland and are priority habitats under the EU Habitats Directive. A number of previously described turlough plant communities were surveyed and, using objective floristic analysis, nine communities identified. Within these nine communities, there was gradation from one community to the next. Overall, there was a broad division between sedge-dominated and grass/forb-dominated communities that is recognised by other authors. The variants in these communities differ, however, between the various authors indicating that there may be gradation from one community to the next in relation to subtle differences in environmental variables. A number of environmental variables that may affect these communities were investigated and depth of deposits over bedrock, soil moisture, date of emptying of the turlough, and water phosphorus and nitrogen were found to correlate with the turlough plant communities in this study.

Two turloughs on the east Burren limestones in County Galway were the subject of a study of current and recent management practices. Farmers with animals on each turlough were interviewed about stock type, stocking density, time of stocking and fertiliser application. Cattle were and still are the dominant stock, but average densities have increased by over 60% over 40 years. One turlough (Caherglassaun) has a history of fertiliser use, and stocking levels are more intense. There was no standard grazing time or stocking density for either turlough. Farmers often operated quite different regimes for the same turlough. The maximum length of any regime was almost seven months, the period without flooding. These results are discussed in relation to the designation of many turloughs as Candidate Special Areas of Conservation (CSACs). Flexibility in devising management plans for the turloughs is recommended.

Plantation forests were established on western Irish peatlands before it became apparent that riparian buffer zones were essential for the health of important salmonid habitats and aquatic ecosystems. The option to retrofit a riparian buffer zone several years prior to the clearfelling of the main plantation may lessen the possible effect of the clearfelling on receiving waters and provide some protection against sediment and nutrient runoff. The option to create a RBZ can only be considered if it can be shown that clearfelling this zone of coniferous forestry along the stream does not pose a significant risk to the water bodies in the short term. To assess this risk, the hydrology, water chemistry and biota at three locations in western peatland catchments within mature, harvestable-age forestry plantations were studied prior to, during and immediately after riparian buffer zones were created. Results indicate that water discharge and suspended sediment increased significantly at two experimental sites post-felling. Maximum and minimum daily temperature and pH also increased significantly at two of the sites. The biological results from macroinvertebrate analysis indicated some significant changes in richness and abundance of species post-felling. The juvenile trout (Salmo trutta L.) densities remained stable over the sampling period and appeared unaffected by the clearfelling operations.

To investigate the nature, diversity and structure of the streamside vegetation, 10 forest sites were selected in the south of Ireland. The vegetation was sampled following the Braun-Blanquet method and gradients in vegetation were examined using belt transects perpendicular to streams. Vegetation relevés were classified using TWINSPAN, which separated five vegetation types: semi-natural oak forest on base-poor soil, conifer plantations, broadleaved stands on base-poor soils, mixed broadleavedconifer stands and broadleaved stands on base-rich soils. Plant species richness in the broadleaved stands was almost double that of conifer plantations. Plant species richness and total vegetation cover decreased with distance from the stream, which is likely to be the result of reduced levels of light, water and soil nutrients away from the streambank. To reveal the stand structure, all trees and shrubs (diameter ! 5 cm) in the relevés were recorded, and the average diameter, density and importance value (structural role) were calculated. Although many introduced species (of which Sitka spruce is the most important) are present in the study sites, native woody species have a greater importance value index (IVI).

Global climate is rapidly changing and while many studies have investigated the potential impacts of this on the distribution of montane plant species and communities, few have focused on those with oceanic montane affinities. In Europe, highly sensitive bryophyte species reach their optimum occurrence, highest diversity and abundance in the northwest hyperoceanic regions, while a number of montane vascular plant species occur here at the edge of their range. This study evaluates the potential impact of climate change on the distribution of these species and assesses the implications for EU Habitats Directive-protected oceanic montane plant communities. We applied an ensemble of species distribution modelling techniques, using atlas data of 30 vascular plant and bryophyte species, to calculate range changes under projected future climate change. The future effectiveness of the protected area network to conserve these species was evaluated using gap analysis. We found that the majority of these montane species are projected to lose suitable climate space, primarily at lower altitudes, or that areas of suitable climate will principally shift northwards. In particular, rare oceanic montane bryophytes have poor dispersal capacity and are likely to be especially vulnerable to contractions in their current climate space. Significantly different projected range change responses were found between 1) oceanic montane bryophytes and vascular plants; 2) species belonging to different montane plant communities; 3) species categorised according to different biomes and eastern limit classifications. The inclusion of topographical variables in addition to climate, significantly improved the statistical and spatial performance of models. The current protected area network is projected to become less effective, especially for specialised arctic-montane species, posing a challenge to conserving oceanic montane plant communities. Conservation management plans need significantly greater focus on potential climate change impacts, including models with higher-resolution species distribution and environmental data, to aid these communities' long-term survival.

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.

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. Relevés 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.

Heathland habitats in Ireland occur primarily in an oceanic setting which is strongly influenced by changes in the climate. Because of the oceanic environment, Ireland has a high proportion of the northern Atlantic wet heaths and alpine and boreal heaths of high conservation value within Europe. Future climate change is widely expected to place additional pressure on these systems. Seven bioclimatic envelope modelling techniques implemented in the BIOMOD modelling framework were used to model wet heath and alpine and boreal heath distributions in Ireland. The 1961-1990 baseline models closely matched the observed distribution and emphasise the strong dependency on climate. Mean winter precipitation, mean winter temperature and elevation were found to be important model components. The fitted model's discrimination ability was assessed using the area under the curve; a receiver operating characteristic plot; the true skill statistic; and Cohen's kappa. A BIOMOD ensemble prediction from all the models was used to project changes based on a climate change scenario for 2031-2060 dynamically downscaled from the Hadley Centre HadCM3-Q16 global climate model. The climate change projections for the individual models change markedly from the consistent baseline predictions. Although the consensus models project gains in climate space for both habitats in other parts of the country, new habitat formation in these areas is unlikely, as current (and hence near-future) land use and other conditions are not likely to favour expansion.

The distribution, habitat and genetic diversity of Irish populations of the Kerry Lily (Simethis mattiazzii) are described. All sites known in 2009, centred around Kenmare Bay in SW Ireland, were sampled. The species occurs in a relatively uniform plant community, classified as 4030 Dry Heath within a low-lying coastal heath complex. A preliminary genetic investigation involving analysis of 21 chloroplast and nuclear gene regions revealed no genetic diversity in the samples examined, suggesting that the species in Ireland comprises a number of meta-populations, within one large, single population confined to the Derrynane area on the Iveragh peninsula in South-west Kerry (v.c.H1) and one on the north of the Beara peninsula, across Kenmare Bay from Derrynane, in West Cork (v.c.H3). A sixth site, at Cahergarriff on the south of the Beara Peninsula has since been discovered. Of the 5,750 flowering plants recorded in 2009, the biggest meta-population, which also had the highest plant de...