Red List of Irish Stoneflies

The 13th All-Ireland Red List covering the Stoneflies of Ireland has just been published. This has been produced by National Parks and Wildlife Service of the Department of Culture, Heritage and the Gaeltacht and the Northern Ireland Environment Agency with acknowledged information and data provided by the Environmental Protection Agency and University College Dublin.

Based on just over 12,000 records for the island of Ireland, the 20 species of stonefly (Plecoptera) on the Irish check list were evaluated against the Red List criteria produced by the International Union for the Conservation of Nature (IUCN). This is the first time the threat status of the Irish stoneflies has been assessed.

Although there are only 20 species of stonefly in Ireland, the species are extremely important component of the natural biodiversity of rivers and to a lesser extent lakes. They are important in nutrient flows and cycling in riverine systems. Under natural conditions, stoneflies constitute a significant proportion of the insect life in streams and rivers and are an important part of the diet of fish and riverine birds such as the Dipper.

Two species are deemed under threat of extinction on the island of Ireland. Protonemura praecox, was assessed as Critically Endangered (which is the highest level of threat) and Capnia atra as Vulnerable. A third species, Perlodes mortoni, was deemed Regionally Extinct in Ireland as it has not been recorded for over 100 years. The remaining species were assessed as Least Concern.

Protonemura praecox has always been rare in Ireland and there must be concern for its survival here as it has not been seen since 1991. Capnia atra is a glacial relict species confined to a small number of sites in the west.

The threat status of the two Red Listed species quite likely reflects increasing average temperatures associated with climate change. Other species confined to higher altitudes may become threatened in the near future as temperatures continue to rise. The threats that climate change, continuing organic pollution, habitat change and sedimentation pose to the stoneflies in Ireland should not be underestimated, with most species highly susceptible to one or more of these pressures.

Habitat changes especially the alteration to natural flow and physical environment of rivers and lakes are likely to have had a significant influence on the present distribution of the Irish stoneflies and the impact of these pose continuing and significant threats.

The authors of the Red List highlight the need for reliable data on the Irish stoneflies. They express concerns that fewer freshwater studies and surveys are producing species-level data. Unless this deficit is addressed, our ability to assess and understand trends in species distributions, and of Ireland’s freshwater biodiversity, will be much diminished.

All of the Ireland Red Lists published to date can be downloaded here.