This award will support the participation of U.S. scientists in a seminar on the "Development of a Unified Perspective on the Organization of Communities and Ecosystems," organized jointly by Dr. Donald DeAngelis of the Oak Ridge National Laboratory and Professor Ei Teramoto of Kyoto University, Japan. United States and Japanese participants will meet in Honolulu, Hawaii during April 1988. The seminar will provide a forum for detailed discussion on the factors which determine the structure and dynamics of ecosystems. The theme of the workshop will revolve around two general questions. Are there regularities in food web structure and, if so, do these regularities reflect constraints related to dynamic stability, energy, or other factors on the ecosystem? How do ecosystem properties and the characteristics of individual species change during succession and evolution? There is considerable disagreement among theoretical ecologists as to what factors are most important in the shaping of food webs. Japanese theoretical ecologists have developed an impressive body of mathematical theory for ecological networks that will facilitate the testing of alternative hypotheses related to ecosystem structure. Becuase much of this information is little known in the United States, the seminar will provide an excellent opportunity for an integration of the work going on in our two countries.