Comparisons of visitor knowledge and behavior between rocky intertidal habitats with different levels of protection in San Diego County, California

Human actions are negatively affecting rocky intertidal ecosystems worldwide, causing habitat degradation, loss of biodiversity, and increased rates of species extinctions. These impacts primarily happen due to visitor behaviors such as trampling and harvesting, which are especially frequent in southern California, USA where the mild coastal climate attracts large numbers of visitors to the shore. As a result, several rocky intertidal habitats in San Diego County are under protection from harvesting as part of the California's network of Marine Protected Areas (MPAs). However, the effectiveness of this protection has remained unclear. In this study, we worked at paired MPAs and non-MPAs in three neighborhoods within San Diego County over 18 months to investigate (1) visitation rates and visitor behaviors, (2) harvesting (collecting) organisms, and (3) visitor knowledge about the San Diego County's MPAs. Although we observed more total visitors within the MPAs (8,983) than in the non-MPAs (5,055), the average size of the MPAs was larger than the non-MPAs, resulting in average visitor densities being only 13% greater in the MPAs. Consequently, the average visitation rates (number of visitors observed during 10-min periods per meter of shoreline) did not differ as a function of protection status. Tide pooling, which involved trampling, was the most common visitor behavior across all MPAs and non-MPAs, with 83% of 14,038 observed visitors engaging in this activity. Organism harvesting was rare and generally more common in the non-MPAs, but it was observed in each of the MPAs. Interviews of 1349 visitors suggested that the main problems with protection of San Diego County's MPAs are (1) a general lack of knowledge about the existence of MPAs and their locations, and (2) inadequate on-site information describing their status, rules and regulations. Our study suggests that efforts to educate the public during their visitation to the rocky intertidal habitats, such as establishing outreach programs, using informational signage, and increasing surveillance and enforcement, can help promote better management of these MPAs and their ecological resources.

Automated summary

Human actions, particularly visitor behaviors such as trampling and harvesting, have negative impacts on rocky intertidal ecosystems worldwide. The protection of these ecosystems in San Diego County, USA, through Marine Protected Areas (MPAs), faces challenges due to lack of public knowledge and inadequate on-site information.