The Ahupua'a concept: relearning coastal resource management from ancient Hawaiians

Isolated in the middle of the Pacific Ocean, Hawaii was one of the last areas to be reached by "western" explorers; as a consequence, some ancient traditions were preserved in Hawaii well into the 19th and 20th centuries, providing an opportunity to learn from a surviving indigenous culture. An account is given of the division of the islands into various units and their exploitation. The smallest major divisions were the "ahupua'as," which spread out at the base along the shore and were self-sufficient units. In this way the ancient Hawaiians recognized the relationship between the land and sea, rainfall and vegetation, nutrients and runoff and preserved the integrity of the delicately balanced ecosystem of which they were a part and upon which they relied for their every need. Modern parallels to this ancient system are broken and irregular; the reorganization of the "ahupua'a" system marked the beginning of the decline of Hawaiian ecosystems. Although steps are being taken to remedy the present situation, Hawaii now ranks among the highest in the nation for its levels of pollution, endangered species and disappearing habitats. More and more, the model for improved management is being sought in the revival of ancient traditions.

Evolution of the tectogene concept, 1930-1965

The tectogene, or crustal downbuckle, was proposed in the early 1930s by F.A. Vening Meinesz to explain the unexpected belts of negative gravity anomalies in island arcs. He attributed the isostatic imbalance to a deep sialic root resulting from the action of subcrustal convection currents. Vening Meinesz's model was initially corroborated experimentally by P.H. Kuenen, but additional experiments by D.T. Griggs and geological analysis by H.H. Hess in the late 1930s led to substantial revision in detail. As modified, the tectogene provided a plausible model for the evolution of island arcs into alpine mountain belts for another two decades. Additional revisions became necessary in the early 1950s to accommodate the unexpected absence of sialic crust in the Caribbean and the marginal seas of the western Pacific. By 1960 the cherished analogy between island arcs and alpine mountain belts had collapsed under the weight of the detailed field investigations by Hess and his students in the Caribbean region. Hess then incorporated a highly modified form of the tectogene into his sea-floor spreading hypothesis. Ironically, this final incarnation of the concept preserved some of the weaker aspects of the 1930s original, such as the ad hoc explanation for the regular geometry of island arcs.