The Scope of the Flood Pulse Concept Regarding Riverine Fish and Fisheries, Given Geographic and Man-Made Differences Among Systems

摘要

We combine a literature review with recent work to assess flood pulse concept (FPC) relevance and predictions with respect to responses of fish populations and river-floodplain fisheries in tropical and temperate regions. In general, results have validated, or are consistent with the FPC, but in some cases, such as in dry-land and high latitude river-floodplains, predictions of some FPC components are equivocal because of climatic, geophysical, and natural history differences and man-made changes. Intemperate regions, timing of the flood pulse with respect to the temperature regime and the annual range of temperature are of fundamental importance for floodplain resource use by native fishes. Geomorphological constraints, combined with hydrologic and edaphic effects, cause considerable variation in primary and secondary production in floodplain and lotic environments along the river course and among systems, affecting community composition, production, and possibly adaptations of native fish. Systems with a strongly modified flood pulse suffer considerable reduction in their biological production and fishery yields, and we hypothesize that diversity of life history types is reduced and community structure is altered such that the resilience offishpopulations to subsequent man-made or natural disturbances is also reduced. Therefore periodic coupling of the river channel with an intact floodplain by a flood pulse that corresponds to—or at least approximates—the natural disturbance regime is of vital importance for fish assemblages and inland fisheries, as well as for the entire system.