Abstract

Modern ecological research has sought to explicitly integrate spatial organization as a critical functioning aspect of communities and ecosystems. Objectives of this study were to establish the spatial scales of variation of reef fish communities and environmental characteristics, and quantify the isolated effect of environmental and spatial variables on fish community composition. By using a spatial survey consisting of 472 line transects on four reef habitat and 12 sites of the Caribbean coast of Mexico we collected fish abundance, environmental characteristics and geographic coordinate data. In order to epitomize the spatial structure of the data we used Principal Coordinates of Neighbour Matrices (PCNM) technique. Partitioning analysis was used to quantify and test the partial effect of environmental and spatial variables on fish community composition. Results showed that significant PCNMs variables (P<0.05) described mainly fine and intermediate scale variation (<30 km). Total explained variation on reef-fish communities fluctuated between 60 and 71%, respect to the survey habitat. The highest fraction of variation was environmental (30-40%). Spatial variation varied from 10 to 15%, depending on the scale of analysis. These fractions were associated with structural components of the environment, ecological processes and external causes. Methods and hypotheses proposed were consistent with the existing theory of reef fish communities and provide new evidence about fish-habitat relationships over explicit spatial scales –useful information for the design of MPA and coral reef ecosystem management.

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