PREDICTING THE VULNERABILITY OF BRYOZOANS AND SPONGES TO DISTURBANCE USING LIFE-HISTORY CHARACTERISTICS

Following on from earlier analyses presented to WG-EMM, meta-analyses of life-history characteristics and their relationships with physical and chemical variables were undertaken for habitat-forming invertebrates other than cnidarians. Particular focus was placed on bryozoans and sponges which are known to form important biogenic habitat in the Southern Ocean. Data were extracted from a global database of life-history characteristics. Bryozoans showed a strong negative relationship between growth rate and age and a strong positive relationship between growth rate and temperature. A multiple regression model suggests that Southern Ocean bryozoans may take more than 50 years to recover following disturbance. Demosponges showed a strong positive relationship between maximum size and age while there were too few data for glass sponges for robust analysis. Most sponges from the Antarctic showed no or very slow growth over considerable periods and it is hypothesised that they will take many decades or even centuries to recover from disturbance particular in areas where natural disturbance is low.