Factors influencing human visitation of southern California rocky intertidal ecosystems

In highly urbanized regions, rocky intertidal habitats attract a large number of visitors for recreation, education, and subsistence harvesting. The collecting, trampling, and handling activities of visitors can have detrimental impacts on intertidal flora and fauna, including reduced abundances and biodiversity and alteration of community structure and function. Despite the large human population in southern California, USA, the level of visitor use at accessible rocky intertidal locations can vary greatly. The goal of this study was to investigate a suite of factors that may influence the number of visitors a site receives. Thirty-two rocky intertidal sites interspersed along ∼175 km of shoreline between Los Angeles and San Diego County in southern California were established and the relative visitor use intensity determined during four aerial surveys conducted during low tide periods. Site-specific characteristic, including cost and availability of parking, physical exertion in reaching a site, popularity of site for educational field trips, density of local human population, and the presence of local attractions, were examined and related to relative use intensity. Popularity of a site for educational field trips was the most significant driver, followed by physical exertion and presence of non-tidepooling attractions. Results from this study may be used as a potential management tool to reduce use and protect anthropogenically-disturbed rocky shores by, for example, regulating educational field trips and manipulating attributes that could alter the degree of physical exertion needed to reach a site.