A simple field method for assessing the ecological quality of riparian habitat in rivers and streams: QBR index

Abstract

An index of riparian quality useful for the management of streams and rivers is presented. The purpose of the index is to provide managers with a simple method to evaluate riparian habitat quality. The index is easy to calculate and can be used together with any other index of water quality to assess the ecological status of streams and rivers. It may also be a useful tool for defining ‘high ecological status’ under the EC Water Framework Directive. The index, named QBR, is based on four components of riparian habitat: total riparian vegetation cover, cover structure, cover quality and channel alterations. It also takes into account differences in the geomorphology of the river from its headwaters to the lower reaches. These differences are measured in a simple, quantitative way. The index score varies between 0 and 100 points. The QBR index is calculated in the field through a two‐sided A4 page form that may be completed in 10 min. The development of the QBR index included trials in four Mediterranean stream catchments in Catalonia (NE Spain). Seventy‐two sampling sites were assessed and results were used to test the index. No taxonomic expertise is needed to apply the index, although some knowledge of local flora is required to differentiate between native and non‐native tree species. These results show that the QBR index may be used despite regional differences in plant communities. The quality ranges obtained when the index is applied are not heavily influenced by observers at the same site. At present, the index is being used by different research teams and tested in a comparative study of 12 watersheds along the Mediterranean Spanish coast. It is expected that the QBR index may be adapted for use in other geographical areas in temperate and semi‐arid zones without changes in the index rationale. Copyright © 2002 John Wiley & Sons, Ltd.