Sponge morphological diversity: a qualitative predictor of species diversity?

1. To the non-specialist, problems are often associated with the quantifica tion of sponge species diversity, as colour, shape and size can be highly v ariable within a single species. These variables can lead to an under-estim ation of the contribution of sponges to the biodiversity of the benthos esp ecially during biological surveys. 2. Sponge species diversity (Shannon H ' values), richness (mean number of species) and morphological diversity (Shannon H ' values) were sampled at s ix sites (6 m depth intervals) on vertical (90 degrees) and inclined surfac es (45 degrees) experiencing different flow regimes at Lough Hyne Marine Na ture Reserve (Ireland). Morphological diversity was sampled independently o f species diversity. The time taken for the collection of both species and morphological diversity was recorded. 3. Morphological diversity was positively correlated with both sponge speci es diversity (r(2) = 0.87, p < 0.05) and sponge species richness (r(2) = 0. 70, p < 0.05). Linear regression was found to be significant for both the r elationships (p < 0.05 for each F-value). A sigmoidal relationship (r(2) = 0.97, P < 0 05) was found between morphological and species richness which proved to be significant (F-value 40.67, p < 0.05). Separate Bray-Curtis de ndrograms and correspondence analysis of morphological and species communit y compositions at the six sites showed very similar clustering and four maj or clusters were identified. 4. The results of the present study indicate that sampling of sponge morpho logical diversity, rather than sponge species diversity and richness may be used as a qualitative estimate of sponge species diversity. Sampling of mo rphological diversity is much less time consuming, both in the field and la boratory, than collecting species diversity data and no specialist knowledg e is required. Consideration is given to the use of such relationships in b iological surveys and bio-monitoring. Copyright <(c)> 2001 John Wiley & Son s, Ltd.