Rocky intertidal monitoring: 2019?2020 results from Redwood National and State Parks
Authors: Ammann Karah , Dinger Eric , Lohse David 
Published: December 2023

This report presents the results of the monitoring surveys done in 2019 and 2020 of the rocky intertidal community at three sites within the Redwood National and State Parks (RNSP) in Del Norte County, California. These sites are part of MARINe (Multi-Agency Rocky Intertidal Network), a regional intertidal monitoring network sponsored by the Bureau of Ocean Energy Management (BOEM), with additional funding and support from local and state governments, universities, and private organizations (see www.marine.ucsc.edu). Funding for annual monitoring in RNSP is provided by the National Park Service (NPS) Klamath Network (KLMN) through a cooperative agreement with the University of California at Santa Cruz (UCSC). Field sampling is accomplished through a collaborative effort between UCSC and RNSP staff. The 2019 and 2020 field crews each consisted of 4 UCSC biologists and three RNSP staff members.
This monitoring program, adapted from MARINe protocols, was designed to identify and follow temporal trends in populations of the common and/or ecologically important organisms in the rocky intertidal community at three index sites within the RNSP. To accomplish this, sites are sampled once a year, and data are collected from permanent plots established to monitor changes in sessile invertebrates, algae, and the ochre sea star (Pisaster ochraceus), and from permanent transects to monitor surfgrass (Phyllospadix spp.) and sea palm (Postelsia palmaeformis). These data are utilized to determine annual status of the community and archived for future use to explore broader spatial and temporal trends. All of the monitored populations varied to some degree over the course of 2019?2020.
The KLMN rocky intertidal monitoring program (?RNSP rocky intertidal monitoring program? in previous reports; Amman et al. 2022), which started in RNSP in 2004, continues to progress successfully. The procedures for data collection, data management, data analysis, and reporting are regularly assessed and have undergone some revisions based on the evolution of the monitoring program (Ammann and Raimondi 2008; protocol revision in progress [Eric Dinger, National Park Service ecologist, pers. comm., Jan 23, 2023]). As such, this year?s report follows on Amman et al. (2022) which introduced new reporting. Amman et al. (2022) and this report include broader scale biodiversity data collected through Coastal Biodiversity Survey protocol. These biodiversity data are sampled at 2 of the 3 sites every sampling period. This report differs from earlier annual reports in shifting from a full summary report, with in-depth analysis, to an administrative data summary report that does not contain in-depth analyses. Subsequent reports will follow this format. This report also reports on optional MARINe protocol data we collected that are not part of the KLMN rocky intertidal protocol (e.g., mussel sizes and sea palm measurements). Some of these optional data measurements may be discontinued in future years. More comprehensive trend analyses of the data are available in the program?s 5-year trend reports, the first of which included data through 2013 (Ammann et al. 2017) and the consecutive trend paper through 2018 (Lohse et al. in press).