Macroinvertebrate communities of poorly buffered afforested and non-afforested streams in western Ireland

Summary

In moorland catchments on granite or quartzite in western Ireland, some planted with conifers, water was more acid and macroinvertebrate diversity lower in afforested streams than at non-afforested control sites. Elminthidae, Plecoptera and some Ephemeroptera occurred in all but the most acidic sites, while Plectrocnemia spp. (Trichoptera) were dominant at the more acidic sites. During floods, afforested sites showed major fluctuations in water chemistry including increases in [H⁺] and labile monomeric aluminium, apparently unrelated to acid precipitation. The importance of such events in structuring the invertebrate community is discussed.