Macroalgal recruitment in artificially disturbed areas: interactive effects of temporal and spatial scale

Abstract

The effect of the surrounding community and spatial extent of disturbance on recruitment was investigated in a mixed stand (dominated by large brown algae of the order Fucales) on a subtidal rocky platform in South Australia. In particular, survival and growth of Cystophora and Sargassum recruits on natural substratum were examined in artificially cleared areas of three sizes (30 × 30 cm, 60 × 60 cm and 100 × 100 cm). Abundance and growth of recruits was monitored for 6 months at both the edge and the centre of the clearances. The influence of clearance size and position within a clearance on the abundance of recruits changes with time. Initially, the size of clearance was most important, with larger clearances supporting denser stands of recruits. However, after 143 days, position within the clearance became important, with greater mortality at the edges than at the centre. The large residual values associated with the analysis were evidence of the variability of the interactions within this community. The results demonstrate the importance of the consideration of spatial and temporal scales, and particularly the position within a disturbed area, in recruitment studies.