Pacific Rocky Intertidal Monitoring: Trends and Synthesis

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Alcatraz Island Long-Term trends

See below for trend graphs

In order to standardize species resolution across all MARINe groups, and over time, some species (typically rare) were lumped for graphical presentation of Long-Term monitoring data. See lumped categories for definitions (some variation occurs between methods and over time).

Photo Plots

Long-Term methods Photo Plot thumbnail

Below are the trends observed for each Photo Plot target species at this site. Long-Term percent cover trend graphs show all species that reached a minimum of 25% cover during any single point in time within a given target species assemblage. Breaks in trend lines represent missed sampling events. For additional species observed that did not meet this 25% threshold, please use the Interactive Map.

For motile invertebrate Species Counts, a mean across all plots was calculated, and only those species with a value of at least 5 individuals for at least one sample are shown. For motile invertebrate size trend graphs by site, please use the Interactive Map.

 Chthamalus/Balanus (Acorn Barnacles) - percent cover

Alcatraz Island barnacle motiles trend plot

Chthamalus/Balanus (Acorn Barnacles) - motile invertebrate counts

Alcatraz Island barnacle motiles trend plot

 Fucus (Northern Rockweed) - percent cover

Alcatraz Island Fucus trend plot

Fucus (Northern Rockweed) - motile invertebrate counts

Alcatraz Island Fucus motiles trend plot

Mastocarpus (Turkish Washcloth) - percent cover

Alcatraz Island Mastocarpus trend plot

Mastocarpus (Turkish Washcloth) - motile invertebrate counts

Alcatraz Island Mastocarpus motiles trend plot

Species Counts and Sizes

Long-Term methods Counts thumbnail

Species Counts and Sizes (where recorded) for Pisaster are shown below for this site. The sum of all individuals across all plots is displayed.

Pisaster (Ochre Star) - counts

Alcatraz Island Pisaster trend plot

Pisaster (Ochre Star) - sizes

Alcatraz Island Pisaster size plot

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Interactive Map

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