The Effects of Industrial Pollution on the Development and Succession of Marine Fouling Communities II. Multivariate Analysis of Succession

Abstract. The successional stages of fouling communities from 3 sites located along a pollution gradient within Port Kembla Harbour (Australia) were compared quantitatively with those from Wollongong Harbour, a relatively unpolluted area located close by.
A multivariate classification of the data showed that the development of fouling communities in Port Kembla Harbour was very different from that in Wollongong Harbour, involving different types of species. In addition, the classification identified a secondary pattern in the data which showed that the species composition of the Port Kembla Harbour communities changed with time, independently of any seasonal effects.
A principal coordinate analysis of the data was able to further expand on these findings. It demonstrated that the succession of fouling communities in Port Kembla Harbour involved a process whereby one group of species (ascidians) was gradually replaced through time by a second group of different species (bivalves). In contrast, the communities in Wollongong Harbour were dominated by inhibitory interactions. The succession in this area mainly involved species (particularly bryozoans) which colonised during the initial stages of development and remained in the communities as they continued to develop.
Changes in the succession of fouling communities from Port Kembla Harbour were thought to be due to the loss of pollution sensitive species, such as bryozoans, from the environment. This was not attributed to the acute, toxic effects of the pollutants, but rather to more subtle and indirect effects.