Species interactions

Species relationships and physical attributes of the environment can intersect in multiple direct and indirect ways, and I am interested in how changes to the physical environment can shape species interactions and structure animal behaviors and food webs.

Functional feeding curves depend on predator and prey densities

Understanding the feeding patterns of sympatric consumers can help reveal potential for density dependent effects on growth. Prey switching, where a consumer transitions between prey items and relieves pressure on a single taxa, can stabilize food webs and allows for consumer populations to persist without extinguishing prey sources. Behavior-mediated foraging has been observed across taxa, and this flexible foraging strategy can relieve some direct competition between consumers if switching to different prey types. However, most existing work on this topic considers only a single consumer and does not investigate changes to feeding relationships in a multiple-consumer system with shared prey. In this work, we examined a system of three consumers sharing three prey categories, and found that more selective consumers engaged in prey-switching initiated by consumer and prey densities, while the diet of more generalist consumers was less influenced by densities of competitors or prey.

 

Intensifying species interactions with environmental change

Physical conditions in lakes, especially water temperature, control a wide range of ecological processes for biotia. For secondary consumers like planktivorous fishes, these physical conditions can directly govern growth or survival, or produce indirect effects by modifying the prey base. In addition, planktivorous fishes can experience density-dependent effects on growth when abundance of consumers exceeds habitat capacity or prey production. Density dependence can strongly regulate system productivity, and can emerge either through changing consumer or prey densities or through physical changes to the environment. In this study, we observe evidence for the onset of density dependence among lacustrine planktivores, and test what environmental factors might be responsible for this pattern.
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