A Heuristic Analysis of Spatial Patterns of Hermatypic Corals at Eilat, Red Sea

Abstract

An earlier analysis of the species diversity of hermatypic corals on line transects in different depth zones at Eilat showed a steady increase in species diversity from shallow water to a depth of 30 m. This had been used as evidence in support of the environmental predictability hypothesis because the deeper zones were in a more predictable environment. Spatial patterns in these transects were studied. A heuristic procedure parsed the transects as if they were texts from an unknown language. This generated a variable which quantified the amount of spatial pattern in a transect. Transects from several depth zones, each classified at several different taxonomic ranks, were parsed, and the amount of spatial pattern over depth and over rank was measured. There was no significant difference in the amount of spatial pattern over depth, suggesting that spatial pattern measured a component of community structure which did not vary with the relative predictability of the environment. There was significantly more spatial pattern at the genus and family ranks than at the species or suborder ranks, suggesting that the component of community structure recovered by the analysis was resident in a level of the system above the species. This supported the critical unit hypothesis postulated here. Species diversity and spatial pattern reflected different components of community structure. Investigation of their behavior over both local and global scales might permit integration of the 2 hypotheses.