Do interrelationships among benthic components mirror disturbance levels?

Abstract

The hypothesis tested in this study is that changes in benthic ecosystem components interrelationships may mirror the degree of environmental stress in the Mediterranean coastal lagoons. Multivariate matrices deriving from four benthic components (macrophytes, zoobenthos, epibenthic decapods and demersal fish) from four lagoonal stations along a well-defined disturbance gradient were compared by means of second-stage non-metric multidimensional scaling (MDS). The resulting inter-matrix distances were used as a proxy for the identification of the degree of disturbance. The approach followed is novel in that it uses information from higher levels of the biological organization by taking into account more than a single benthic component, thus representing broad categories of functional groups. The second-stage MDS plots depict differences between inter-component distances in the sampling stations according to the degree of disturbance they experience and the BIOENV analysis demonstrates that certain components are correlated with the environmental variables at a higher degree in the most disturbed stations.