Biodiversity Quadrat Surveys

The Baseline surveys of rocky intertidal ecosystems (SC) project includes both Long-Term Monitoring and Biodiversity Surveys done in the North Coast of California. Long-Term Monitoring Surveys use fixed plots to document changes in percent cover, or abundance of targeted species or species assemblages. This fixed-plot approach allows the dynamics of rocky intertidal species to be monitored with reasonable sampling effort and provides sufficient statistical power to detect changes over space or time. Biodiversity Surveys provide detailed information about biodiversity and community structure. These surveys were designed to measure diversity and abundance of algae and invertebrates found within rocky intertidal communities on the western coast of temperate North America. This metadata record documents the Biodiversity Quadrat Surveys done as part of the NC Baseline surveys of rocky intertidal ecosystems. Biodiversity Quadrat sampling consists of recording the number of mobile invertebrate species within thirty-three 0.5m x 0.5m quadrats placed along 11 transects of variable length extending from the upper intertidal to the low intertidal. Biodiversity Surveys are comprised of three biological components, all sampled along the same transects: (1) point contact estimates of intertidal cover and substrate characteristics, (2) swath transects to estimate the density of sea stars and abalone, and (3) quadrat sampling to estimate the density of mobile invertebrates. Biodiversity Surveys are done throughout the year at sites ranging from Southeast Alaska to Baja California Sur, Mexico. Selected sites are resampled on a 3-5 year cycle. A site is defined as a contiguous rocky bench of at least 30m.