Effects of docks on total cover and community assemblage of marine algae

Abstract

Overwater structures such as docks shade the benthic communities around them, which influences both the total cover and community assemblage of marine algae. We hypothesized that algal cover decreases, and community assemblage shifts, with proximity to the dock. To test this, we sampled twelve locations near the town of Friday Harbor using transects and photo-quadrats. Data were analyzed using multiple regression to separate the effects of distance from the dock and depth. Results indicate that total cover does decrease with proximity to the dock, while patterns in community assemblage were less clear. Our methods can be applied to assessing community assemblage on a practical scale, to inform regulations and policy regarding overwater structures.