Composition and community structure of Phylum Echinodermata of the rocky intertidal zone’s San Lorenzo-Salinas, Ecuador

Abstract

Echinoderms are important organisms in the marine environment as they act as bioindicators, biological controllers, consumers of organic matter, among others. In Ecuador, the study of echinoderms has focused on protected areas (PA), thus giving the opportunity to carry out descriptive and/or quantitative studies in other rocky areas outside of a PA; Therefore, this research aims to describe the composition, abundance and community structure of the echinoderms of the rocky intertidal zone of the San Lorenzo-Salinas beach, establishing a baseline of species identified through community indices and associated environmental variables. During the period from July to October 2021, it was carried out through visual censuses of rocky substrates, applying the quadrant transect technique. A total of 17,766 individuals belonging to 10 species of echinoderms, identified for the class Echinoidea, were recorded in situ: 1 species; Class Ophiuroidea: 2 species; Class Holothutoidea: 3 species; Class Asteroidea: 4 species. The species E. vambrunti was the most representative with a total of 11,744 specimens, thus being the most abundant organism in the study. The Shannon-Weaver index presents a low diversity (10 species) and a high abundance (17766 organisms) that was evidenced by the average of 1.2 ± 0.56 bits; the Pielou uniformity index reached its statistical mean of 0.14 bits, the Simpson dominance had an average of 0.51 ± 0.2. At the same time, in ANOVA, none of its values ​​exceeded 0.5 of the standard normal distribution, which gives a value below the critical value, indicating that the specific richness of the echinoderms is independent of the sampled area in San Lorenzo Salinas.