Preface: Assessment of physical habitat characteristics in rivers, implications for river ecology and management

Abstract

Physical habitat characteristics are an extremely important factors determining the structure and composition of fluvial biological communities and fluvial ecosystem functioning. Existing methods for characterising the physical realm of river habitats are increasingly important, not only for monitoring river ecosystem health and the success of river restoration projects but also for increasing the understanding of river ecosystem functioning and improving the efficiency of management actions. However, there is no scientific consensus on which methods to use for long-term monitoring and which river features to monitor because many fundamental questions relating hydrological, geomorphological and biological characteristics remain unanswered and because river habitats are monitored to cover a wide variety of objectives. Several initiatives worldwide have demonstrated the importance of analysing and discussing the application of different methods to assess river habitat characteristics for different objectives. It would be interesting to achieve a common approach for river habitat characterization for different objectives, especially for mid- to long- term monitoring programs and different river management issues (e.g., monitoring river restoration projects). More elusive but no less important is the contribution of these methods to understanding the interactions between river habitat architecture and river functioning. In this regard, the Physical Habitat Assessment Methods in Rivers (PHAM) seminar was organised in Santander, northern Spain, in November 2009 to review current practices on river habitat assessment. The contributions presented in that seminar and some later contributions form the basis of this special volume. These papers identify the main factors creating and maintaining river habitats, review physical habitat assessment methods and propose improvements and adaptations, apply different methods in distinctive geographical areas and characterise river habitats for estimating habitat availability of different fish species.