Pacific Rocky Intertidal Monitoring: Trends and Synthesis

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Survey Methods

Long-Term Monitoring and Biodiversity Surveys are done by MARINe (Multi-Agency Rocky Intertidal Network). These intertidal monitoring surveys occur throughout the year at sites ranging from Southeast Alaska to Mexico.

Long-Term Monitoring

  • Click here (PDF link) for Long-Term Monitoring Survey protocol

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. The MARINe survey methods can be divided into two tiers: “core” procedures that are done by all groups at all sites, and “optional” procedures that are done by groups with funding & staffing to support additional work.

Core procedures include the following:

  1. "Photoplots" used to monitor percent cover in assemblages such as barnacles, mussels, and rockweed. Percent cover of all species occurring within these assemblages is estimated by using a point contact grid, either in the field or from photos in the lab.
  2. Line transects used to estimate cover of surfgrass, kelps, and other algae not well-sampled by photoplots.
  3. Irregular plots used for counts and sizes of large, mobile species such as seastars and limpets.

Optional procedures include the following:

  1. Counts of mobile species within photoplots.
  2. Estimates of barnacle recruitment from rock clearings and plates.
  3. Estimates of Mytilus californianus (CA mussel) size structure.
  4. Deployment of temperature loggers.

Researchers monitoring intertidal algae and invertebrates

Biodiversity Surveys

  • Click here (PDF link) for Biodiversity Survey protocol

  • For a species lookup table (including general taxonomic group name and common name, if available) of ALL species observed during the Biodiversity Surveys, please click here (PDF link).

Increasing threats to the coastal environment due to human development, pollution, and overharvesting has created a need for more information on the health of coastal habitats. One of the greatest challanges confronting the management and conservation of these nearshore ecological communities is balancing the need for protection against the importance of promoting increased access, which leads to increased awareness. Paramount in meeting this challange is determining the spatial and temporal patterns in these ecological communities. Without this fundamental information, management and conservation decisions could be made in ignorance leading to undesirable outcomes.

The 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.

The goals of the project are to:

  1. Determine the diversity and site-wide abundance of intertidal algae and invertebrate species.
  2. Create a topographic map for use in assessing the spatial distribution of species within each site.
  3. Reveal long-term influences such as climate change and coastal development on intertidal communities and individual species.
  4. Examine patterns of biogeography with a particular emphasis on locations where there may be large changes in species composition and diversity.

Biodiversity Survey set up at Cambria, CA

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See Also