The effects of human and environmental disturbances on predator-prey interactions

Disturbance events have effects on species as well as on the interactions between species. This project includes two experiments designed to determine how human and environmental disturbances affect the interactions between species in a food web. The first experiment examined how a prey grasshopper species’ mortality and food intake changed when subjected to human agitation. Grasshoppers reduced their food intake and had higher mortality rates when subjected to human disturbance, similar to how they responded to the risk of predation by spiders. The second experiment examined how the top-down control of a predator was affected when abiotic conditions were altered in a way that emulated the invasion of an exotic plant. Shading released prey from top-down control, potentially facilitating the invasion of the exotic species by removing its competition. To make effective management decisions, managers need to recognize the impact that disturbances can have on species interactions and the ecosystem.