|Site types that use this protocol|
Macro-invertebrates are a very diverse group of organisms with a wide range of environmental tolerances and preferences and are generally abundant in freshwater habitats. Communities are therefore likely to show both qualitative and quantitative responses to a full spectrum of possible environmental changes. In most situations macro-invertebrates are also relatively easy to sample, qualitatively at least, and keys for the identification of most elements of the British fauna are readily available.
Species presence, abundance and deformities are determined 3 times per year at river and lake sites.