biodiversity quadrat surveys of rocky intertidal ecosystems

The Baseline surveys of rocky intertidal ecosystems (SC) project includes both Long-Term Monitoring and Biodiversity Surveys done in the South 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 SC 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.

潮间带岩质生态系统基线调查（SC）项目涵盖于加利福尼亚南海岸开展的长期监测与生物多样性调查两项工作。长期监测调查采用固定样地，用于记录目标物种或物种集合的盖度百分比或丰度变化。该固定样地方法可在合理采样工作量下监测潮间带岩质物种的种群动态，并具备足够的统计效力以检测空间或时间尺度上的群落变化。生物多样性调查则提供生物多样性与群落结构的详细信息，本项调查旨在量化北美温带西海岸潮间带岩质群落中藻类与无脊椎动物的多样性及丰度。本元数据记录针对SC项目潮间带岩质生态系统基线调查中的生物多样性样方（quadrat）调查进行说明。生物多样性样方采样指在沿从潮间带高潮区延伸至低潮区的11条长度不等的样带（transect）上布设的33个0.5m×0.5m样方内，记录移动性无脊椎动物的物种数量。生物多样性调查包含三类沿相同样带开展的生物学调查组分：(1) 潮间带盖度与底质特征的样点接触法估算；(2) 条带样带法估算海星与鲍鱼的种群密度；(3) 样方采样法估算移动性无脊椎动物的种群密度。生物多样性调查全年在覆盖从阿拉斯加东南部至墨西哥下加利福尼亚南部的多个样地开展，所选样地以3至5年为周期进行重采样。样地定义为面积至少30米的连续岩质滩涂。