Phytoplankton assemblages in four wetlands created on cutaway peatlands in Ireland

The deliberate flooding of cutaway peatlands has resulted in the creation of 3700ha of new wetlands in the Irish Midlands. None of Ireland's cutaway wetlands have been designated as artificial water bodies for the purposes of the Water Framework Directive (2000/60/EC) (WFD). Nevertheless, ensuring that the created wetlands do not adversely affect downstream water quality or the potential of neighbouring designated rivers to achieve their environmental objectives under the WFD is of primary concern to environmental managers and regulators. Phytoplankton communities in four created wetlands were monitored over a 33-month period. The study aimed to assess whether phytoplankton communities in the created wetlands have the potential to be reliable indicators of chemical water quality. Longer term changes in the phytoplankton communities in two of the wetlands were also assessed. Indicator species analysis identified the presence of a number of algal species regarded as reliable indicators of eutrophic and mesotrophic water quality. Longer term trends indicated that the created wetlands have a propensity to develop phytoplankton blooms in the early years following flooding, in response to high ambient phosphorus concentrations. The data indicate a trend of improving water quality as the created wetlands mature and stabilise.