Ecological indicators performance during a re-colonisation field experiment and its compliance with ecosystem theories

The study was carried out in an intertidal rocky community dominated by the algae Corallina elongata. Experimental plots were cleared and macroalgae and fauna were removed. Multivariate analysis was performed to examine the convergence of the disturbed plots with the surrounding community during recovery. Shannon-Wiener Index, Margalef Index, Pielou evenness, Eco-Exergy and Specific Eco-Exergy were applied to characterise the state of the community during the process. Results show that the replacement of species over time happens both with the macroalgae and associated macrofauna community. Species richness increased rather rapidly and species composition was similar in disturbed and undisturbed areas. After 7 months, diversity was consistently higher in the community undertaking recovery. Eco-Exergy and Specific Eco-Exergy provided useful information about the structural development of the community but lacked discriminating power with regard to the informational status of the system. The observations appear to illustrate a case explainable by the Intermediate Disturbance Hypothesis (IDH). Overall, the characteristics of a systems' recovery after disturbance appear to be dependent on the spatial scale of the disturbance. If a disturbed area is small when compared to a contiguous non-disturbed one, complexity (information and network) will recover prior to biomass.