Santa Cruz Island Reserve

26 Sep, 03 AM - 27 Sep, 07 AM

The goal of this research is to determine patterns of change in the distributions and abundances of rocky intetidal macrophytes and macroinvertebrates in the Southern California Bight following a 20 year period of ocean climate change and increasing urbanization of the Southern California mainland. Research plans include re-assessming sites originally established by Mark M. Littler and colleagues in the mid-1970s using the same methodologies. Data generated will allow robust comparisions of changes in species composition and abundances. The specific purpose of this research is to perform these re-assessments at Littler's Willows Anchorage and Prisoners Harbor sites on Santa Cruz Island. The proposed trip is a cointinuation of the project described below. A small amount of additional sampling at Willows Anchorage is required to complete the study. The work to be performed at Willows Anchorage is part of a collaborative multi-year, field sampling program with Pete Raimondi at UC Santa Cruz, involving restudies of rocky intertidal populations and communities at a selected subset of the BLM sites established by Littler and colleagues in the mid-1970s. Sites and transects will be relocated using available maps, photos, and site descriptions. A metal detector will be used to search for remnant bolts that were embedded into the substratum to mark transect lines during the 1970s. Maps and site descriptions (including photographs) will be inspected to place transects on the same benches studied during the mid-1970s. A one-day reconnaisance visit is planned with Dr. Seapy of CSU Fullerton and Maurice Hill of MMS who worked on theBLM Santa Cruz sites in the 1970s. The full site assessment at Willows Anchorage is planned for April 5-8. After relocating or repositioning transects using descriptions and photographs, GPS coordinates will be recorded for the site, and stainless steel bolts will be fixed into the substratum to remark transect locations for future use. Two to three parallel transect lines will be re-established perpendicular to the shoreline at the Santa Cruz site(s). Attempts will be made to place transect lines in the exact positions used previously by relocating bolts or other landmarks at transect line heads and placing lines in the same compass orientation described by Littler and colleagues. Where possible, plots will be distributed along each transect at the same intervals identified in previous studies to produce a stratified sampling program with coverage over the entire intertidal zone. Two plot sizes will be employed: 0.30 m x 0.50 m (0.15 m2) plots will be used to sample all intertidal biota while 1.0 m x 1.0 m (1.0 m2) plots will be used for larger seaweeds (e.g. kelps and surf grasses) and larger mobile invertebrates (e.g., giant keyhole limpets, black abalone, etc.). This protocol will result in approximately 40 0.15 m2 and 40 1.0 m2 plots for each site. Detailed records will be taken in the field of the contents of each plot. These records will include a listing of all species found in each plot plus estimates of their abundance. Visual scanning will be used to estimate the percent cover of all macrophytes and macroinvertebrates in the field; counts of all macroinvertebrates also will be made except for sponges, colonial ascidians, and other invertebrates where individual organisms cannot be discriminated. Field data for each plot will be recorded so as to provide maps that locate species in plots. Unknown specimens that cannot be identified in the field will be placed in labeled vials or plastic bags, fixed in 10 % formalin-seawater if necessary, and returned to the laboratory for identification. Collecting of specimens will be minimal and limited to only problematic taxa. In addition to the above field data and records, color photographs will be taken of each plot using 35 mm SLR cameras or digital camera equipped with electronic strobes. 35-mm photographs will be developed as color transparencies. Cover of species in plots will then be determined in the laboratory by projecting 35 mm photographs onto a grid of dots distributed in 2-cm intervals on white, fine-grained Bristol paper. Each photograph or digital image will be scored twice to generate in excess of 100 point intercepts per scoring session. The plot data will then be used to calculate the mean cover and density of each species for each 0.3 m (1.0 ft) tidal interval and for the entire shore. Plot tidal heights will be remeasured where plot locations cannot be reestablished with certainty; otherwise plot tidal heights will be those reported previously. These data reductions will form the basis for comparisons between similar reduced data from the mid-1970s for the Santa Cruz Island sites and data gathered during this study. Prior BLM data will be keyed into electronic spreadsheets, updated for taxonomic accuracy and then checked for taxonomic consistency with data obtained during the planned sampling program. Site diversity will be calculated from cover and density data based on richness (total number of sampled taxa), and Shannon?s H? and Pielou?s J? indices. The absolute and relative abundances of functional groups of macrophytes and macroinvertebrates will be determined and compared with similar assessments performed on data obtained in the mid-1970s. Community structures derived from newly gathered data will be compared with those reported in the mid-1970s using both univariate and multivariate approaches.

Visit #1862 @Santa Cruz Island Reserve

Approved

Under Project # 1506 | Research

Reassessment of the 1970s BLM surveys

faculty - California State University (CSU), Fullerton

Reservation Members(s)

Group of 2 Research Assistant (non-student/faculty/postdoc) Sep 26 - 27, 2003 (2 days)

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Dorm 2 Sep 26 - 27, 2003
Jeep 2 Sep 26 - 27, 2003