Distribución y abundancia de macroinvertebrados marinos asociados a la zona intermareal rocosa de San Mateo, desde julio a diciembre 2022, Manta-Ecuador.

Abstract

Macroinvertebrate communities are of great importance, as they play an indispensable ecological role in the biotic functioning of intertidal zones, so their study is of vital interest in order to generate conservation strategies for these communities. The objective of this work was to determine the distribution and abundance of marine macroinvertebrates in the rocky intertidal zone of San Mateo. For this purpose, weekly sampling was carried out at low sea during the months of July to December 2022 using the methodology of linear transects and quadrats, registering 18 quadrats for each monitoring. A total of 6793 individuals distributed in 4 phylum and 22 species were observed. The most abundant phylum was the Mollusca (71.3%) with the species Shiphonaria maura (27.70%) as the most representative, which was located in the supralittoral zone, with the phylum Arthropoda (15.3%), Echinodermata (12.8%) and Annelida (0.46%) being observed as less abundant. Diversity was analyzed by means of biological indices, which showed a medium diversity and richness of species according to the Shannon and Margalef index, while the Pielou index showed a high level of equitability and a low dominance among species according to Simpson's dominance. There were no significant differences in the indexes between the rainy and dry months according to the Wilcoxon test. The most abundant zone was the supralittoral zone (52.8%), finding significant differences with the meso and infralittoral zones, since the latter showed greater similarity in the nMDS analysis. The physicochemical variables did not present direct relationships with the diversity indices; however, abundance had significant correlations with pH and salinity according to Pearson's statistic, while temperature did not present a significant correlation. It is concluded that the intertidal zone in this study presents a medium diversity, where mollusks were the most representative phylum and the supralittoral zone was the most abundant, the pH and salinity parameters are related to the presence of species.