Rocky intertidal monitoring: 2017–2018 results from Redwood National and State Parks

Abstract

This report presents the results of the monitoring surveys done in 2017 and 2018 of the rocky intertidal community at 3 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 2017 and 2018 field crews each consisted of 4 UCSC biologists and 3 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 3 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 2017–2018. The KLMN rocky intertidal monitoring program (“RNSP rocky intertidal monitoring program” in previous reports), 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., Feb 24, 2022]). As such, this year’s report contains some departures from past years’ reports. New to this report is the inclusion of 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 begins a shift away from previous full summary annual reports that contained in-depth analyses towards a simpler data summary. It 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. Subsequent reports will follow this format, with some simplification. 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).