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.

岩潮间带生态系统基线调查（SC）项目涵盖美国加利福尼亚州南海岸开展的长期监测与生物多样性调查两类工作。长期监测调查采用固定样地方法，记录目标物种或物种集合的盖度百分比与丰度变化。该固定样地方法可在合理采样工作量下实现岩潮间带物种种群动态监测，并具备足够的统计效力以检测空间或时间尺度上的变化。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，此类调查旨在测算温带北美西海岸岩潮间带群落内藻类与无脊椎动物的多样性及丰度。本元数据记录所描述的是作为SC岩潮间带生态系统基线调查组成部分的生物多样性样方调查。生物多样性样方采样工作包括：在沿11条长度不等、覆盖潮间带高潮区至低潮区的样带布设的33个0.5米×0.5米样方内，记录移动性无脊椎动物物种的数量。生物多样性调查包含三项生物学采样模块，均沿同一样带开展：（1）潮间带盖度与底质特征的样点接触法估算；（2）带状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开展，调查点位覆盖从美国阿拉斯加州东南部至墨西哥下加利福尼亚半岛南部的区域。选定的调查点位将以3至5年为周期进行重复采样。调查点位的定义为：至少30米长的连续岩质滩涂。