Ecosystem services provided by groundwater dependent wetlands in Irish karst

Turloughs, the focus of this study, are ephemeral lakes and they are mostly groundwater dependent. They are present mostly in Ireland and have been compared hydrologically to polje for the period inundation and lacustrine deposits. They are flooded for some periods across the year (typically in the winter) but usually dry up in summer months. Turloughs are protected under the Water Framework Directive (WFD, Directive 2000/60/EC) and the EU Habitats Directive (92/43/EEC). Ecosystem services can be defined as the conditions and processes through which natural ecosystems sustain and fulfil human life. These can be classified as provisioning, regulating, and cultural and examples of them are water and raw materials production, flood risk attenuation, carbon sequestration. The determination of the ecosystem services can help analyse different scenarios linked to pressures like road drainage schemes, water supply and wastewater disposal.

 

Seven turloughs (Blackrock, Lough Coy, Lough Aleenaun, Lough Gealain, Caranavoodaun, Skealoghan, Coolcam) have been selected from a previous study and samples of waters were collected monthly to determine carbon and nutrients. Carbon and nutrients were also determined on soil samples taken from the turlough catchment. The overwhelming majority of wetlands act as long-term sinks for CO₂. To determine whether this is the case for some of the turloughs in the study, greenhouse gases from soils and water were monitored and balances were worked out. Ecosystem services were quantified through various models which had to be adapted to the special conditions present in the turloughs.

 

The seven turloughs have different hydrological characteristics. Hydrology is the main driver of vegetation distribution therefore ommunities are distributed in zones arranged along the flooding gradient. Aquatic invertebrates also show a succession of communities through the hydroperiod.

 

The seven turloughs studied provide a variety of hydrological characteristics, habitat, soil and vegetation and offer different ecosystem services. Each ecosystem service was quantified using appropriate models. Almost all the turloughs are at risk from anthropic activities and potentially from climate change. Important ecosystem services for these turloughs are flood mitigation, nutrient retention, carbon sequestration, habitat preservation and recreational activities.