This volume contains the texts of invited papers presented at the Fourth International Conference on Mediterranean Ecosystems (MEDECOS) held in Perth, Western Australia during August 1984. It thus follows three previous meetings, Chile (1971), California (1977) and South Africa (1980). There has been no formal international body to organize these meetings, merely a continuity of purpose provided by the common interests of the scientists concerned in the English-speaking world. Following previous themes on structure, fire and role of nutrients in mediterranean ecosystems, MEDECOS was structured around the theme 'Resilience in Mediterranean Ecosystems'. The invited speakers were requested to deal with particu lar aspects of this subject, and offered papers were encouraged to do so as well. This provided a broad framework for discussions which at the same time highlighted many of the major conservation issues arising from extreme natural events and human-induced disturbances in the mediterranean regions. The proceed ings were issued on the last day of the conference and provided two-page accounts of each of the contributed papers and posters (Dell, B. (ed. ) 1984 Proceedings of the 4th International Conference on Mediterranean Ecosystems. Botany Dept. , University of Western Australia). This volume was reserved for the review papers whose aim was to explore general principles and unifying concepts at all levels in the study of resilience. Perth, December 1985. VII List of contributors B. Dell 1. E.