We attempted to discern the contributions of physical habitat,water chemistry, nutrients, and contaminants from historic lead-zinc miningactivities on the riffle-dwelling benthic fish community of the SpringRiver, a midwestern warmwater stream that originates in Missouri and flowsinto Kansas and Oklahoma. The Spring River has a fish community thatincludes the Neosho madtom, Noturus placidus, a species Federally listed asthreatened. Although anthropogenic factors, such as contaminants, limitedpopulations and densities of fishes, an integrated approach that assessednatural and anthropogenic factors was necessary to effectively estimate theinfluence of the latter. Fish populations in the Spring River, especiallyNeosho madtoms, seem to be limited by the presence of cadmium, lead, andzinc in water and benthic invertebrate food sources and physical habitat.The population density and community structure of fish in the Spring Riveralso seem to be related to water chemistry and nutrient measurements.Concurrently, diminished food availability may be limiting fish populationsat some sites where Neosho madtoms are not found. Furthermore, many of thenatural factors that may be limiting Neosho madtom and otherriffle-dwelling fish populations in the Spring River are likelycharacteristic of the physiographic region drained by the upper reach andmany of the tributaries of the Spring River. Our results also indicatethat competition between the Neosho madtom and other species within theriffle-dwelling benthic fish community is an unlikely cause of limitedNeosho madtom populations in the Spring River.
