Midwestern streams are dominated by complex algal growth during much of the year. Interactions among predators, grazing minnows and crayfish could strongly affect this algal structure. Interactions between grazers and their shared predator may influence algal habitat structure and furthermore have cascading effects on other stream-fish interactions with important consequences for community structure. This study will focus on such effects and possible behavioral mechanisms. Surveys throughout Oklahoma will test the generality and strength of relationships among the algivorous minnow Campostoma anomalum, crayfish, their shared predators, algal standing crop, abiotic habitat variables and various aspects of stream-fish community structure. Manipulative experiments will isolate abiotic and biotic variables that affect interactions among two grazers (C. anomalum and crayfish), their shared predator (bass) and algal structure. Further experiments will study the affects of algal structure on interactions among two invertivorous fishes and their shared predator (bass).
