Ecological principles and stream restoration

Abstract

The practice of stream restoration has grown rapidly over the past 20 years. In a recent editorial in the journal Aquatic Conservation, ORMEROD (2004) reported more than 300 papers in the ISI® database containing the terms ‘river restoration’, ‘river rehabilitation’, ‘stream restoration’ or ‘stream rehabilitation’ in the title, abstract or keywords. Much progress has undoubtedly been made, such as the establishment of the River Restoration Centre in the UK, the European Centre for River Restoration in Denmark, and national and international conferences specialising in stream restoration (e.g. HANSEN et al. 1998). Yet despite these encouraging signs, much remains to be done in addressing misconceptions of running waters and their restoration. Rivers and streams are conveyors of water, but they are more than conduits. They are ecosystems with diverse animal and plant life, with fluvial and ecological processes that maintain habitats and transform matter received from the catchment and produced in the streams themselves. They shape the landscape and create the floodplain within which they fashion their stream bed in a predictable but ever-changing mosaic pattern. Nevertheless, rivers and streams are the natural ecosystems that have been changed the most by man (MALMQVIST & RUNDLE 2002; MEYBECK 2002) and they are often managed as if they were merely conduits. Few streams in ‘developed’ parts of the world have evaded the ‘hard engineering’ approach, which has changed their inherent, natural properties. The time has surely come to move on from engineering-driven stream management into the realm of ecologically-driven catchment management and stream restoration (POSTEL & RICHTER 2003). As part of the 29th SIL Congress in Lahti, the SIL Working Group on the Conservation and Management of Running Waters convened a workshop entitled ‘Ecological principles and stream restoration’. The aim of the meeting was to review progress in this field and to consider the extent to which ecological science impinges on stream restoration. This paper briefly summarises some of our main conclusions.