INTEGRATING BIOLOGICAL REALISM INTO HABITAT RESTORATION AND CONSERVATION STRATEGIES FOR SMALL STREAMS

Successful habitat conservation or restoration must be biologically ba sed, which requires an understanding of habitat variables most influen cing fish; the relative influence of each habitat variable and the spa tial scale over which each operates. Determining necessary habitat con ditions requires examination from several perspectives, including obse rvation of individual fish during all seasons and population analysis over a range of spatial scales. There is a definite spatial hierarchy of influences that must be addressed to separate those habitat conditi ons responsible for presence and abundance from those habitat conditio ns responsible for within-stream distribution. A case study of habitat factors influencing smallmouth bass (Micropterus dolomieu) in Missour i streams indicates that examination at the smallest spatial scales al lows one to determine the influence of habitat conditions (depths, vel ocities, cover factors) relating mainly to the fish's distribution in a stream reach. Evaluation of populations at the stream-system level a llows an understanding of how individual fish preferences relate to am ounts of habitat as determined by geomorphic and fluvial dynamic force s and how this influences standing stocks throughout a stream system. Evaluation at the ecoregion level shows the overriding influence of ph ysiographic variables on both the presence and abundance of fish acros s stream systems, as well as the importance of land use.