Polynesian Irrigation: Archaeological and Linguistic Evidence for Origins and Development

Abstract

Most tropical and subtropical Polynesian high islands exhibit landscape modifications such as terracing or ditching, or both, resulting from prehistoric irrigation of taro (Colocasia esculenta). Because of the technological and hydraulic similarities between such Polynesian taro irrigation and Southeast Asian rice irrigation, some prehistorians have traced Polynesian irrigation practices back to a Proto-Austronesian homeland region in Southeast Asia. Other scholars have advocated an independent development of pondfield irrigation in the Pacific Islands. In this paper we draw upon two independent lines of evidence to test these alternative hypotheses. Chronologically controlled archaeological evidence for irrigation indicates a relatively late development of irrigation works in those Islands investigated thus far. This evidence is corroborated by systematic comparison of the lexical terms associated with irrigation among speakers of Oceanic languages. The linguistic analysis yields no evidence for an early terminological set associated with pondfield agriculture, but distinct sets of western and eastern Polynesian cognate reflexes indicate independent development of irrigation in those regions. KEYWORDS: Oceania, Polynesia, prehistoric agriculture, irrigation, taro.