The conservation of freshwater macroinvertebrate populations: a community-based classification scheme.

1.A novel conservation indexing protocol is presented which aims to summarize aquatic macroinvertebrate data obtained from inland flowing- and still-water sites in Great Britain. Unlike other summary expressions of conservation value, the Community Conservation Index (CCI) accounts for community richness in the final analysis, as well as the relative rarity of species present.2.Examples are provided to show how taxonomically rich ecosystems can obtain very high values of CCI that are broadly equivalent to CCI scores obtained from other sites supporting nationally rare species. In addition, the CCI is capable of local adjustment, to accommodate nationally common species occurring outside their normal range.3.Examples show typical CCI outputs from a range of riverine and still-water habitats, and illustrate how this analysis can help in the day-to-day assessment and management of both lotic and lentic ecosystems. The index has already been used in legal submissions for public inquiries on Sites of Special Scientific Interest protected under British law and has contributed to the designation of such sites. It has also been used to inform management decisions on sites selected as candidate Special Areas of Conservation and as an operational tool using routinely obtained datasets.4.The CCI provides an empirical basis for conservation initiatives, programmes and strategies, by producing a summary of aquatic invertebrate data over any appropriate scale of time and space. Furthermore, the final analysis need not be constrained by distribution of nationally rare species, but can indicate exceptionally rich or regionally unusual invertebrate populations. Copyright 2004 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]