Can functional groups be used to discriminate between sites along a water quality gradient in Maltese coastal waters?

Abstract

This study investigates whether macroalgal functional groups can be used to distinguish between rocky shores subject to different degrees of anthropogenic stress. Macroalgae from seven sites situated along the rocky upper infralittoral (0-50 cm depth) of Malta and Gozo were seasonally sampled in 2003 and 2004. A total of 86 macroalgal species belonging to the following functional types were found: 6 articulated, 23 corticated-terete, 6 crustose, 35 filamentous and 16 foliose. The ANOSIM procedure applied to the percentage cover of each functional group detected significant differences between years, sites and seasons. The SIMPER procedure showed that the functional groups foliose, crustose and corticated-terete mostly contributed to determine the observed patterns in hierarchical groupaverage linkage cluster analysis and nMDS ordination. On the basis of the multivariate analyses made, it may be concluded that functional groups discriminated among sites.