PISCO: Intertidal: Coastal Biodiversity Surveys: Swath Surveys

This metadata record documents the Swath surveys for PISCO intertidal coastal biodiversity surveys. Swath sampling consists of recording the number of seastars and abalone on eleven 2m wide transects of variable length extending from the upper intertidal to the low intertidal. Intertidal surveys are comprised of four 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 seastars and abalone, (3) quadrat sampling to estimate the density of mobile invertebrates, and (4) topography (elevation relative to mean low low water (mllw)). Intertidal coastal biodiversity surveys are conducted throughout the year at sites ranging from Southeast Alaska to Baja California, Mexico. Selected sites are resampled on a 3 to 5 year cycle. A site is defined as a contiguous rocky bench of at least 30m.本元数据记录旨在说明PISCO潮间带海岸生物多样性调查所采用的条带采样（Swath sampling）方案。条带采样指在11条宽度为2米、长度不等的样线（transects）上记录海星与鲍鱼的数量，样线延伸范围覆盖高潮带至低潮带。 潮间带调查包含4项采样内容，所有采样均沿上述样线开展：(1) 采用点接触法估算潮间带覆盖度与底质特征；(2) 利用条带样线法估算海星与鲍鱼的种群密度；(3) 通过样方采样（quadrat sampling）法估算移动无脊椎动物的种群密度；(4) 地形测定：即测定相对于平均最低低潮面（mean low low water, MLLW）的海拔高度。 潮间带海岸生物多样性调查全年开展，调查点位覆盖范围从美国阿拉斯加东南部延伸至墨西哥下加利福尼亚州。选定的调查点位将以3至5年为周期进行重采样。 调查点位被定义为连续分布的岩质滩涂，规模至少为30米。