Effects of Intertidal Algal Canopies on the Marine Gastropod Lottia scutum

Abstract

In this study, we investigated how intertidal algal canopies affect susceptibility of limpets to predation and also how the temperature experienced by limpets at low tide affects limpet susceptibility to predation at high tide. Specifically, we studied the effects of habitat amelioration by Saccharina sessilis and Fucus distichus on L. scutum populations. We hypothesized that in the F. distichus zone (during the low tide), predation would be high in open areas (because limpets in these areas are visible to foraging bird predators), and that predation would be low under the F. distichus canopy (because limpets would be hidden from bird predators during low tide exposure). Secondly, we hypothesized that in the S. sessilis zone, predation would be higher under the canopy (because sea stars commonly reside under the canopy to avoid stress from the low tide (Burnaford, 2001) 4 than in open areas during the high tide. Additionally, we investigated how long it takes L. scutum to recover from heat stress and regain their escape responses after low tide exposure. We predicted that limpets exposed to cooler low tides (simulating conditions under a shaded algal canopy) would recover their escape responses faster than limpets exposed to warm low tides (simulating conditions in open sun-exposed intertidal areas).