Spatial and temporal variability of sessile benthos in shallow Mediterranean marine caves

Hypotheses on the spatial and temporal distribution of sessile assemblages in submerged marine caves have rarely been tested. Classically, the distribution of cave benthos has been related mainly to the physical gradients along the exterior-interior axis. Using a multifactorial sampling design, we examined the distribution of species assemblages within 3 different caves in Southern Italy. Non-destructive sampling was repeated at 4 different times over a period of 11 mo. Results showed an overall pattern of change in the structure of the assemblages along the exterior-interior axis of the 3 caves (i.e. among sectors). Significant differences in species assemblages, however, were also observed within sectors (i.e. among areas), and changes in assemblages varied inconsistently with time and among caves. This result suggests a high complexity of the processes determining spatio-temporal distribution patterns in marine caves, which are context- and scale-dependent. Results also showed the uniqueness of these assemblages, which has important implications for their conservation and management.