Dissertation Research: Gulls as Cross-ecosystem Links in New England Coastal Communities.

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Some of the most striking examples of community change appear to be driven bychanges in the abundance of particular species with cascading effects on other members of anecosystem. Seabirds exert substantial effects through predation and by modifying abioticfactors, thereby determining species richness of assemblages in both marine and terrestrialhabitats. In New England, gulls have increased dramatically since the early 1900s, and arelikely transforming coastal terrestrial and intertidal communities through their activities.However, their impacts are virtually unknown. The goal of this research is to understand themechanisms by which nesting gulls impact plant (terrestrial herbaceous and intertidal algae)assemblages. Gulls may have top-down effects on algal diversity in the intertidal throughpredation on secondary consumers (crabs) that forage on algal grazers (littorines). Birdstransfer marine-derived nutrients and energy from intertidal to terrestrial habitats via guano,and as a consequence they may impact terrestrial plant diversity from the bottom-up. Ipropose a combination of experimental manipulations and comparative sampling methods toinvestigate these effects. Policies in aquatic ecosystems (e.g. seabird restoration) can affectboth aquatic and terrestrial systems. Understanding gull impacts in marine and terrestrialhabitats will contribute to informed management practices.