The threespine stickleback (Gasterosteus aculeatus) as a modifier of ecological disturbances

Background: The influence of human activity on ecological communities can be mediated as well as modulated by species with a central role in regulating community composition. The threespine stickleback is a common species in temperate aquatic ecosystems that could serve such a role. Question: Does the threespine stickleback (Gasterosteus aculeatus) modulate the impact of human-induced eutrophication on ecological communities? If so, what are the pathways and mechanisms? Methods: Review of studies investigating the influence of eutrophication on the dynamics and characteristics of stickleback populations, and how changes to the population mediate and modify the impact of eutrophication on other species. Results: Eutrophication influences the abundance and characteristics of stickleback, which impacts other species through density- and trait-mediated effects on species interactions and the habitat. The effects can be complex and include feedback loops, and extend far beyond the stickleback population through the myriad of linkages among species. The changes can interact with other changes to the ecosystem, such as species invasions and climate change, and further alter the impact of ecological disturbances. Conclusions: The threespine stickleback modulates the effects of eutrophication on communities and alters ecological and evolutionary processes. However, relatively little is known about the ultimate effects on ecosystems. Thus the complexity of ecological network architecture needs to be considered by combining experimental investigations of linkages among species with whole-ecosystem studies.