"Efforts to improve habitat for fish, particularly salmonids, have a long history and intervention is extensive and ongoing. Resource managers and practitioners spend considerable time and money implementing stream habitat projects. Installation of artificial habitat structures is a consistently popular approach. In this thesis I describe effects of artificial structures on stream morphology and fish density and highlight management implications. In the first chapter, I address the effects of habitat structures on stream morphology in a low-power system. Formal evaluations of the effects of habitat structures on stream morphology in low-power systems like the North Branch of the Au Sable River have been very limited relative to the popularity of these projects. I demonstrate that while artificial structures produce some desired habitat characteristics, their effects tend to be localized and may be outweighed by deposition. In the second chapter, I evaluate the relationship between the density of Brown Trout (Salmo trutta) and Brook Trout (Salvelinus fontinalis) relative to the density of artificial structures. While there are significant relationships for both species, responses are highly variable, and differ by species and size in relation to structure type. I also show the influence of stream context on relationships between fish and artificial structures."--Page ii.
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