Patrick Kirch is interested in the origins and diversification of the cultures and peoples of the Pacific, in the evolution of complex sociopolitical formations (especially "chiefdoms"), in prehistoric as well as ethnographic subsistence systems (especially those involving some form of intensification), and in the reciprocal interactions between indigenous peoples and the island ecosystems of the Pacific. He is engaged in inter-disciplinary collaboration with ecologists, soil scientists, paleobotanists, and quantitative modelers. A continuing focus has been on the Lapita Cultural Complex of the western Pacific, widely regarded as the "foundation" culture underlying the later diversity of island Melanesian and Polynesian cultures. A long-term field program in the Kahikinui district on the island of Maui focuses on protohistoric transformations in environmentally marginal landscapes. Another on-going project is an archaeological study of the remote Mangareva Archipelago in French Polynesia.