Date of Award

Winter 2006

Project Type


Program or Major


Degree Name

Master of Science

First Advisor

Larry Harris


The impact of non-native species is one of the most critical issues facing management and conservation today. When these invaders are generalist predators, their impacts on native communities can be a major restructuring force for ecosystems. A new voracious predator the Asian crab, Hemigrapsus sanguineus , joins another non-native established species, Carcinus maenas, along the majority of the New England coastline. What remains poorly understood is how the two introduced predators may modify local communities, especially considering their impact on native prey, such as the rough periwinkle snail, Littorina saxatilis. The goal of this research is to investigate the vulnerability of these snails to shell-breaking predators by examining their clinal variation in shell morphology and crab-induced scarring history. Focused studies on the variable morphology of this native gastropod coupled with predation studies provide a greater understanding of the ecological and evolutionary consequences of the arrival of novel predators to an ecosystem.