Alpha diversity of marine mammals of the Mexican South Pacific

Abstract

Knowledge of the alpha diversity contributes to the determination of conservation priorities by identifying regions with high species richness and/or a large number of endemic, rare, or endangered species. The present study focused on the evaluation of species richness and composition of the marine mammal community off the coast of Oaxaca. A total of 293 surveys were carried out between December 2011 and April 2015. Additionaly, observation and stranding records found in the literature and zoological collections (corresponding to the period 2008-2014) were revised to estimate alpha diversity. The results allowed us to conclude that the current richness of marine mammals for the state, comprises 21 species distributed in 2 orders, 3 suborders, 5 families, and 17 genera. This represents a 75% increase in the known richness prior to this study. All species of marine mammals are found in some risk category according to the NOM-059-Semarnat-2010 (Mexico), IUCN, and CITES. Our results highlight the importance of the Oaxaca region in the Mexican South Pacific as a priority area for conservation, because of its high degree of richness, considerable diversity in species composition, and the concentration of vulnerable or endangered marine mammals.