Are Multiple Predator Effects on a Shared Prey Influenced by Habitat Complexity?

<div class="line" id="line-16"> It is becoming increasingly important to understand how multiple predators impact a shared prey resource, especially within the context of both invasive species and species experiencing poleward range expansions. Typically multiple predators will interact with each other, leading to either risk enhancement or risk reduction for shared prey. However, in multiple predator effects studies, habitat is often ignored, despite its importance in in&fllig;uencing predator-prey relationships. It is possible that increasing habitat complexity can either alleviate or exacerbate the effects of multiple predators. In New York estuaries, the long-established invasive green crab, Carcinus maenas, is an important consumer of bivalve prey. Additionally, populations of blue crabs, Callinectes sapidus, are increasing in New York estuaries, likely due to warmer winters associated with a changing climate. During mesocosm experiments, green and blue crabs were allowed to forage alone and together as both con- and hetero-speci&filig;c pairs at 4 levels of habitat complexity. Rates of consumption when crabs foraged as pairs were compared to predicted values based on consumption rates when crabs foraged singly. Both the presence of multiple predators and habitat complexity had signi&filig;cant effects on prey consumption.</div>