The Macroinvertebrate Fauna and Environmental Quality of the Oakers Stream, a small tributary of the River Frome (Dorset)

The Oakers Stream is a small, acidic tributary of the River Frome. The stream rises in Oakers Bog SSSI and flows through Oakers Wood before entering farmland in its lower reaches. The stream is characterised by a variety of habitats, ranging from ‘natural’ shady pools and woodland sites, to channelized and re-sectioned lower reaches. Macroinvertebrate surveys were carried out in summer 2007, autumn 2007 and spring 2008, recording a total of 108 taxa in 6 sites. The list included the beetle Agabus brunneus which is a Red Data Book species with a ‘vulnerable’ status. The environmental quality, as determined by RIVPACS, varied from ‘fairly good’ to ‘poor’. However, the relatively high species richness for an acidic stream in the River Frome catchment may be a reflection of the contrasting habitats and land uses that occur over the stream’s short length.