PISCO: Intertidal: Coastal Biodiversity Surveys: Point Contact Surveys: Summarized Data

Point Contact sampling consists of recording the diversity and abundance of invertebrates and algae along 11 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 3-5 year cycle. A site is defined as a contiguous rocky bench of at least 30m. The Point Contact summary data include the percent cover of 20 of the most abundant species (or substrate classifications) observed across all sites during the Point Contact Surveys. This percent cover was calculated based on the first point only. The top 10 species were selected based on the total percent cover across sites. Additional species were then added to the selected species, based on regional differences between sites. The percent cover for the resulting 20 species is listed for each site, along with the overall ranking across all sites for each species. If a specific species is not listed for a specific site, that species was not observed on the first point during the Point Contact Surveys conducted at that site.

点接触采样法（Point Contact sampling）指沿11条长度不等的样带，记录从高潮潮间带延伸至低潮潮间带区域的无脊椎动物与藻类的多样性及种群丰度。本次潮间带调查包含4项核心内容，均在同一条样带上开展：(1) 潮间带覆盖度与底质特征的点接触估测；(2) 带状样带法估测海星与鲍鱼的种群密度；(3) 样方采样法估测移动无脊椎动物的种群密度；(4) 地形测量（相对于平均最低低潮面（mean low low water, MLLW）的海拔高度）。
该沿岸潮间带生物多样性调查全年开展，覆盖站点范围从美国阿拉斯加东南部延伸至墨西哥下加利福尼亚半岛。选定站点每3至5年进行一次重采样。单个站点被定义为长度至少30米的连续岩质滩涂。
点接触采样的汇总数据涵盖了所有站点在点接触调查中观测到的20种优势物种（或底质分类类型）的盖度百分比，该盖度百分比仅基于首个接触点计算得到。首先依据各物种在所有站点间的总盖度百分比选出前10种物种，随后根据站点间的区域差异补充剩余物种，最终形成包含20种物种的盖度百分比数据集，同时附带各物种在所有站点中的总体排名。若某站点未列出某一物种，则说明在该站点开展的点接触调查中，首个接触点未观测到该物种。