Background:

The last floristic survey of marine algae species from Guadalupe Island was published in the 1980s, including a summary of surveys from collections dating back to the beginning of the past century.

Goals:

To update the species inventory and analyze the macroalgae community on Guadalupe Island.

Methods:

Four sampling procedures were undertaken, during January, April, and October 2013, and May 2014, from intertidal and subtidal zones, at depths of between 10 and 18m, depending on the locality.

Results:

102 species were identified as representatives of the three main taxonomic divisions; 14 species belonging to Chlorophyta, 29 to Ochrophyta, and 59 to Rhodophyta, related to 39 families and 65 genres. Of the organisms found at a specific level, 30 are new records, 13 are taxonomically synonymous, and 59 correspond to previous registries. The Margalef index shows that the highest biologic richness occurred in May 2014, as while the highest diversity also appeared in that same month, as the Shannon-Wiener index indicates. Data were statistically evaluated with the PERMANOVA analysis, showing statistical differences between the analyzed factors (depth, season, zone, and locality), thus demonstrating high heterogeneity at the localities, mainly between the northern and western areas of the island.

Conclusions:

Guadalupe Island has high species richness and diversity. In accordance to SIMPER analysis, the species that contribute most to the qualitative differences found in the analyzed factors are Zonaria farlowii, Jania rosea, Sargassum palmeri, Dictyopteris undulata, and Padina durvillei.