Global and local patterns in the use of macrophytes as substrata by hydroids (Hydrozoa: Anthoathecata and Leptothecata)

Abstract

Hydroids are one of the most important animal groups colonizing marine macrophytes. This study presents the diversity of hydroid species in plant substrate samples taken from three points of the São Sebastião Channel, southeastern Brazil. The selectivity level of each hydroid species was inferred from the number of its occurrences on each species of macrophyte. Red and brown algae, especially species belonging to the genera Galaxaura and Sargassum, respectively, presented the highest diversity index of epiphytic hydroids. The epiphytic hydroid fauna of São Sebastião Channel is mostly comprised of opportunistic species, presenting low substrate selectivity. A broader cluster analysis of the epiphytic hydroid fauna reported in several studies around the world suggests that hydroids are primarily related to their geographical distribution and may be secondarily related to the lineages of macrophytes.

Keywords:

• Biogeography
• Brazilian coast
• commensalism
• epiphytic hydrozoans
• epiphytism
• São Sebastião Channel

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Acknowledgements

The authors are very grateful to Eurico C. Oliveira-Filho (IB-USP) for the identification of the Brazilian macrophytes, and to Alvaro E. Migotto for several suggestions and for help in the identification of some hydroids. This study was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) (Procs. 2000/14932-2, 2004/09961-4, 2007/06560-7), Conselho Nacional de Pesquisa e Desenvolvimento (CNPq) (Procs. 471960/2004-7, 557333/2005-9, 490348/2006-8, 305735/2006-3, 481227/2007-5), and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES Procad 2007).

Notes

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark