Historic land-use and the influence of catchment characteristics on faunal communites of small streams, Dorset, UK

Abstract

Historic land-use is considered in relation to the faunal communities of small streams in south-east Dorset, UK. Four high and five low alkalinity streams, encompassing the full range of geological conditions found in the area, were examined. Land use influences included arable land, forestry and urbanisation. A clear link has been demonstrated between geology, land use and the faunal communities of the nine streams, with distinct communities occurring in the two main groups of low and high alkalinity sites. Although riparian effects such as shading, channelisation and point-source pollution influence the faunal communities, their effect is slight in our dataset compared with the overriding catchment characteristics which determine water chemistry, hydrology and the use to which the land is put. With the current level of disturbance the environmental quality of most sites on the high alkalinity streams is ‘good’ to ‘very good’ whereas that of the low alkalinity sites is ‘fairly good’ to ‘poor’. The low alkalinity streams appear to be more sensitive to disturbance than the groundwater-fed high alkalinity stream