Research Technical Report

Analysis of Community Diversity on an Ecological Gradient Through a Kelp Forest in Monterey Bay, California

Geller, J., T. Campbell, T., S. Litvin, S. Lonhart, and S. Palumbi (November 2016)

Poster presentation at the Western Society of Naturalists Annual Meeting, November 10-13, 2016, Monterey, CA

ABSTRACT

Local-scale biodiversity is affected by immigration and in situ ecological interactions. Previous studies have shown that kelp forests act as filters of onshore movement of zooplankton, including larvae of benthic species. Kelp forests thus alter the species pool that contributes to onshore diversity. We studied the composition of assemblages on settlement panels deployed through a Macrocystis pyrifera kelp forest at the Hopkins Marine Station in Monterey Bay, central California. Three sets of ten panels were placed outside, within, and onshore of the kelp forest from August 2014 to February 2015. A mitochondrial COI fragment was amplified from DNA extracted from all biomass from each set of plates and sequenced on an Illumina MiSeq instrument. Pooled sequences clustered to produce 390 operational taxonomic units (OTU). 23 OTU matched binomial database records with pairwise identity of 95% or greater. All reads in each set were mapped to OTUs to enable comparisons across regions. Assemblages from each region of the kelp forest were distinct, however outer and mid-forest assemblages were more similar, while the onshore sample was strikingly divergent. Diversity ranged from averages of H=3.0 to 3.4, insofar as DNA reads reflect OTU abundance, but did not vary significantly on this ecological gradient (Kruskal-Wallis H=2.76, p=0.25). Lower barnacle read count inshore (X²=6.66, p=0.035) was consistent with past studies of larval depletion. Any such depletion, however, did not limit species diversity in the inshore community in this time period.