Stanford biology professor Peter Vitousek, a native Hawaiian, has studied firsthand the symbiotic relationship between Hawaiians and their environment. Now over a millennium after the first Polynesians landed on Hawaii he hopes our civilization can learn something from a society whose own survival depended on understanding its natural world, Vitousek said in a lecture in the Class of 1978 Life Sciences Center on Friday afternoon.
Island ecosystems are relatively constant and can therefore serve as perfect models for understanding wider patterns of human-environmental interactions, Vitousek said. Geological and biological factors remain constant on Pacific islands because they are composed of basalt, have volcanic topography and feature low, fixed biodiversity, he said.
Despite this stability, the environmental and geological conditions necessary to support complex societies vary even within an island's own system. An island's physical isolation highlights these differences including varied soil nutrient levels, high rainfall gradients and disparities in age of underlying rocks and renders their impacts on human civilization easier to isolate and understand.
Societal constants also make Pacific islands "ideal for research," Vitousek said.
Most Pacific islands were originally inhabited by members of the Polynesian civilization, who settled in places as diverse in size and climate as Hawaii, New Zealand and Easter Island, he said. The newcomers were able to develop complex societies that were similar in their cultural characteristics despite adapting to their respective environments, according to Vitousek.
Vitousek demonstrated through overlaying maps how early Hawaiian natives used both soil age and rainfall in order to determine the "sweet spots" for their crops.
Because the Hawaiian islands rose at different times, the basalt that composes them varies in age, Vitousek said. This basalt weathers and loses its nutrients at different rates due to rainfall variation and other environmental factors, he said. The result is that younger basalt has the potential for more fertile bands which are able to sustain the food production necessary for a complex society, Vitousek said.
Due to such variations, two distinct types of agriculture developed in Hawaii dryland and wetland cultivation. Both systems, which adapted to function within certain environmental constraints, produced surpluses that enabled Hawaiians to advance past subsistence farming into more varied trades, according to Vitousek.
"This is more like Iowa than village gardening," Vitousek said, referring to Iowa's mass agricultural production.
Labor requirements and output vary among the different types of agricultural production on the islands, Vitousek said.
On the island of Kauai, where deep canyons permitted the cultivation of wetland taro crop, large surpluses could be produced with minimal labor, thereby leading to a "relatively strong society," he said. Irrigating crops through that method also required societal organization that encouraged development, Vitousek said.
Dryland crops, which were most predominant on the island of Hawaii, required far more labor and produced lower yields than their counterparts. Communities using such techniques were therefore unable to advance as quickly as others, according to Vitousek.
Because certain groups advanced more quickly than others, frequent wars erupted between the Hawaiian islands as certain "drylanders" attempted to taker over wetland areas, Vitousek said.
Vitousek is currently expanding his research methodology to explore the rise and decline of other Polynesian societies. On Easter Island, for example, local Polynesians just missed reaching the soil threshold that would have allowed them to intensify their agricultural production and develop sustainably, he said. As a result, the society collapsed and the island was left desolated, Vitousek said.
The people of the small island Tikopia part of the Solomon Islands faced the same choices as their Easter Island counterparts, but were able to build a complex, lasting society by using an orchard-based agricultural system and regulating their population growth, he said.
"It's not like we can extrapolate the results from Hawaii everywhere, but we can take the process and apply it elsewhere," Vitousek said.
Vitousek's lecture, "Hawaii as a Model System for Understanding Soils, Ecosystems and Human-Environment Interaction," was sponsored by the biological sciences department, as part of its 10-part Cramer Seminar Series.
