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My research is focused on freshwater ecosystem and fish ecology and trophic dynamics.
Freshwater Ecosystems
Activities include research designed to improve our scientific understanding of land–water interactions, enhance management expertise, and restore and protect ecosystems. For example:
- Restoration of salmon (Oncorhynchus spp.) habitats in river ecosystems
- Salmon life history, survival, ecology and behavior in altered and natural environments
- Responses of ecological and human systems to policy changes that influence salmon management plans (e.g., Endangered Species Act and salmon conservation–restoration; Habitat Conservation Plans [HCP]; assessing watershed risks to salmon habitats)
- Landscape scales and functions of freshwater ecosystems:
- Role of fluvial geomorphic and hyporheic systems in structuring stream habitats and scaling of river basins
- Short-term ecosystem changes (e.g., nutrient cycling, fish bioenergetics)
- Long-term ecosystem changes (e.g., natural disturbance regimes, climate change)
- Influence of land-use practices upon stream—riverine—estuarine habitats and fish and wildlife communities.
Fish Ecology and Trophic Dynamics
A concern in the Pacific Northwest is that growth and residence time of juvenile salmon (Oncorhynchus spp.) in different freshwater habitats may be limited by the temporal abundance and structure of preferred food resources. My research calls for extending paradigms for prey and habitat selection by fish to examine predictions in different ecosystems. The ability to predict the diet and habitat use of organisms as a function of prey resource availability and habitat profitability to the consumer is essential to developing a more mechanistic understanding of forager behavior and for potentially unraveling competition and community-level questions.
Studies on elemental cycles are focused upon understanding processes regulating the cycling of carbon and nutrients in food webs of lakes, lotic systems and estuaries. Nitrogen cycles are examined in metabolically active interface sites (i.e., sediment/water) characterized by high levels of organic matter and use by fish prey organisms. Research includes hypotheses pertaining to the similarity or dissimilarity of processes and their importance to the productivity of fish food webs.