Latitudinal regionalization of epibenthic macroinvertebrate communities on rocky reefs in the Gulf of California

ABSTRACT

We report on a latitudinal pattern in the structure and species composition of epibenthic macroinvertebrate communities on rocky reefs along a gradient of eight degrees of latitude in the Gulf of California. We provide quantitative evidence of a prominent shift in the taxa dominating these communities, particularly the sessile taxa (Cnidaria, Bivalvia, Annelida, Ascidiacea and Porifera). This pattern was not found in non-sessile taxa (Echinodermata, Decapoda, Cephalopoda, Gastropoda and Polycladida). Based on Bray–Curtis similarity and indicator species analysis we found that the macroinvertebrates of rocky reefs in the Gulf of California are distributed in three broad regions, indicating that sessile taxa are creating such a structure and are related to environmental changes tied to latitude. The northern region (>28° N) was a temperate zone with the coolest water in winter and highest chlorophyll a concentrations, where Octocorallia of the genus Muricea were the dominant taxa. The central region (∼24–28° N) had a mix of oceanographic features of the northern and southern regions and was dominated by Echinodermata in terms of species richness and density. The southern region (<24° N) is a subtropical zone with typically warm and clear water, and dominated by Hexacorallia (stony corals). The southern area was less diverse and had lower densities than the central and northern areas. These three communities correspond to known oceanographic discontinuities in the Gulf of California. This implies that future coastal management plans and conservation efforts in the Gulf of California must be regionalized to support their distinct ecological communities.

RESPONSIBLE EDITOR:

• Alf Josefson

KEY WORDS:

• Ascidiacea
• Cnidaria
• Crustacea
• Echinodermata
• Mollusca
• Polychaeta
• Polycladida
• Porifera
• sessile and non-sessile
• spatial patterns

Acknowledgements

We thank Ira Fogel at CIBNOR for editorial services and suggestions; Jaime Gómez-Gutiérrez at El Centro Interdisciplinario de Ciencias Marinas (CICMAR), La Paz, for comments and suggestions that improved the manuscript; and the Gulf of California Marine Program at Scripps Institution of Oceanography, especially the DataMares project coordinator Marcia Moreno-Baez during her tenure. This study was part of the Reef Fauna Project of the Universidad Autónoma de Baja California Sur.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This project was supported by the Walton Family Foundation, the David and Lucile Packard Foundation, the WWW Foundation, the International Community Foundation and the Leona M. and Harry B. Helmsley Charitable Trust. David Alonso is a recipient of a grant from the Spanish government (CGL2012-39964). Karol Ulate is a recipient of doctoral grants and fellowships from the Consejo Nacional de Ciencia y Tecnología of Mexico (CONACYT 36745312610557), Escuela de Ciencia Biológicas of the Universidad Nacional de Costa Rica; Ministerio de Ciencia y Tecnología, and the Consejo Nacional para Investigaciones Científicas y Tecnológicas of Costa Rica. The project was also supported by a CIBNOR mobility grant (900–801) to Leonardo Huato-Soberanis.