METAZOAN COMMUNITY STRUCTURE IN RELATION TO THE FRACTAL DIMENSIONS OFMARINE MACROALGAE

A measure of the complexity of a habitat independent of habitat type h as long been required by benthic ecologists, particularly when compari sons between habitats or substrates need to be made and related to par ameters of community structure. Using marine algae from the Isles of S cilly, UK, and their associated epifaunal communities as a testbed we have investigated how the use of fractals may be one method of solving some of these problems. The fractal dimensions of 4 species of macroa lgae with a range of growth forms indicate an increasing order of comp lexity, which is paralleled by differences in the community compositio n and increasing diversity of 2 different size fractions of the epifau nal communities associated with each alga. We conclude that the fracta l dimensions of the habitat provide a numerical expression of complexi ty which is easy to calculate, is independent of the nature of the hab itat and is related to the scale at which the habitat may be viewed by the size hierarchies of animals which occupy it.