Structure and spatial variation of the hermatypic coral assemblages of the southern coast of Jalisco, in the Mexican Central Pacific

The hermatypic coral ecosystems of the southern coast of Jalisco, Mexico, present an important species richness and coverage for the Mexican Central Pacific. However, knowledge of these ecosystems of the Jalisco coast is fragmented. Studies have concentrated on few localities, employing a limited number of coral health indicators, and gaps still remain in the knowledge of ecosystem structure and its local and mesoscale variation. This study evaluated spatial variations in the coral assemblage structure in six sites on the southern coast of Jalisco, Mexico, five of which had never been studied before. Sampling was conducted in September 2019, utilizing a total of 35 transects (each of 25 m in length). The cover of each coral species was recorded, as well as other benthic groups and substrate types. Different community attributes, patterns of similarity in coral species and their relationships with the benthic habitat structure were evaluated in each site. The results showed that the observed richness (8 species) represented 83.7% of that expected by chance. Significant spatial variation was found between coral patch sites and coral community sites, in terms of species richness, Shannon diversity and live coral cover, as well as in the structure of the coral assemblage and the benthic habitat. The results evidenced these conditions despite the existence of a considerable dominance of branched corals of the genus Pocillopora. The species that contributed most to the differences between coral patch sites and coral community sites were Pocillopora damicornis, Pocillopora capitata and Pocillopora verrucosa. For their part, the benthic habitat structural elements that favored the differences between site conditions were live coral cover and turf.