Anchor Species and Epiphytes in intertidal Algal Turf

Abstract

This study characterizes a turflike vegetation composed of benthic marine algae, in the low intertidal in southern California, by means of quantitative relative abundance data collected over a 2-yr period. The algae comprise a relatively homogeneous assemblage that is fastened to the substrate by one to six "anchor" taxa with thalli that persist throughout the year and become reestablished on exposed surfaces within several months. Two species of Corallina together occupy more than 60 percent of the total substrate sampled. Epiphytes attached to these anchor species include 42 species that are consistently found and another 25 that are infrequently or incidentally recorded. Abundances of several of the epiphytes fluctuated during the sampling period, but the number of species present showed no distinct seasonal change. In the northern GulfofCalifornia a similar-appearing turf includes several of the same species in different proportions, but anchor species are different. Many unrelated taxa in both turfs exhibit the same morphological characters. A census of macroinvertebrates associated with the southern California vegetation suggests that grazing is not important in maintaining the relatively uniform height of these plants.