Marine and brackish-water molluscan biodiversity in the Gulf of California, Mexico

Abstract

A database containing taxonomic, distributional and ecological data of 2194 species of marine molluscs (1528 Gastropods, 565 Bivalvia, 59 Polyplacophora, 21 Scaphopoda, 20 Cephalopoda, and one Monoplacophora) known to the Gulf of California, Mexico, was used to analyse their latitudinal and bathymetric distribution, to define their substrate preferences, and to elaborate a biodiversity model for the study area. The model was based on a comparison between the set of data associated with each species (i.e., depth range, associated substrates and geographic distribution within the Gulf) and the environmental conditions prevailing in the Gulf (i.e., depth and substrate), using a georeferenced grid of 2 × 2 nautical miles. Results are presented as predictive biodiversity distribution maps for the major molluscan groups. Putative biodiversity ranges were defined using a percentage accumulative system with 20% classes. As expected, the highest biodiversity occurs along the coastline and around the islands. A south-north biodiversity gradient is observed, although it is less evident between the southern and central Gulf.