The Ecology and Management of Wood in World Rivers

Fish Relationships with Wood in Large Rivers

Maciej Zalewski, Magorzata Lapinska, and Peter B. Bayley


Abstract.—The importance of wood for fish as individuals, populations, and communities and its role in the formation of habitats in large rivers is reviewed. Small-scale effects of wood on fish dominate the literature, but effects on populations and communities at the basin scale are not additive because increasing development of wood-influenced habitats modifies the transport of water, nutrients, and sediments. This, in turn, creates and maintains habitat resulting in increased spatial and temporal diversity and system resilience, which subsequently affect different life cycles of riverine fishes. Such effects depend on location; the relative influence of instream wood on fish and physical processes tends to decrease downstream in large basins, but the converse may be true in floodplains as their influence increases downstream. Because climatic factors control hydrology and temperature throughout the basin, and fish responses to management depend on large-scale, longer term processes as well as smaller ones, the research results reviewed here are assessed in the context of a basin-scale framework, the Ecohydrology Concept (EHC). A restoration strategy based on a basin-scale framework fosters a natural disturbance regime, increases the ability of the system to absorb impacts, and utilizes natural processes in the development of management tools. Reintroduction of wood in large rivers is an essential strategic component but will not, on its own, achieve significant benefits for fish and other biota without at least partial restoration of hydrological cycles, riparian vegetation, selected floodplains, and the associated natural disturbance regime.