My Research    

        I am interested in the role fishes play in stream ecosystems.   Particularly, how do different fish species contribute to the health of a stream.  This includes the effects fishes have on primary production (the rate energy is captured from the Sun), the cycling of nutrients, the breakdown of organic matter, and on abundance and diversity of other members of stream food webs (i.e, aquatic invertebrates and other fishes).  
        To date, we have addressed the role of 12 species.  We hypothesized different species have different effects because the mechanisms of their interactions potentially differ.  All of these studies were done in experimental streams located at the University of Oklahoma Biological Station (UOBS), but we are conducting an experiment now that is in a real stream.  We have found that different fishes have different effects on the processes mentioned above, and we are conducting experiments to determing the mechanisms behind each species effect .  
        In nature streams with only one fish species are rare, so I am also interested in effects of multi-species assemblages on ecosystem function.  We think that fishes may compliment one another to enhance the overall regulation of the ecosystem.   To address this issue, we conducted an experiment where we manipulated fish diversity (i.e., the number of fishes species).  Ecosystem productivity was enhanced with increased fish diversity in this experiment, which supported our argument that different fish species may compliment one another.  Also important is the effect fishes have on other fishes in the stream.  For example, in a recent experiment, we showed that some fish species grow more when a second species is present in the community.  
        As we continue to investigate the interactions among fishes and stream ecosystems, we will contribute to the overall understanding of the importance of organisms to proper ecosystem function.  This will help environmental managers and policy makers make well educated decisions regarding our natural resources.

Experimental Streams.                                              Orange Throat Darter has a strong effect             Me fixing a seine
                                                                                     Stream Productivity

               

Red shiners in Experimental Streams                  Starting an Experiment in February 2002                 An experiment in a real stream