Macroinvertebrate status in relation to critical loads for freshwaters: A case study from N.E. Scotland

The Critical Load concept provides a method for the assessment of an ecosystem's sensitivity to acidification. This paper examines how variations in critical loads for freshwaters are reflected by the diversity and abundance of macroinvertebrates. The results indicate that acidified sites, those with the lowest critical loads, have significantly fewer species than less sensitive sites. The data are discussed in terms of ordination analysis relating catchment attributes to critical loads and macroinvertebrate status. It is concluded that although critical loads provides a good predictor for biotic status it is not as sensitive as parameters such as pH or alkalinity.