Oct. 25, 2012

農村共有資源の管理と農民間の協調行動―中国雲南省における灌漑管理の事例分析―

伊藤順一 (農林水産省農林水産研究所)

Collective Action for Irrigation Management -A Case Study of Rural Yunnan, China-

Junichi Ito (Policy Research Institute, Ministry of Agriculture, Forestry and Fisheries)

要旨Abstract

 本稿では進化論的ゲーム論の概念を援用しながら,共有資源の利用に関する仮説を提示し,その検証を試みた.実証分析は筆者が中国雲南省昆明市で独自に収集したデータをもとに,当地の灌漑管理を対象として行った.計量分析の結果は提示された仮説をほぼ肯定するものであった.灌漑管理の出役頻度は,非農業就業機会が乏しく,用水の賦存量が適度に少なく,集落内の経済格差が小さく,共同体の中に様々な社会的交換ゲーム(共同作業の機会)が埋め込まれている集落で高い.反面からいえば,これらの条件を満たさない集落では,「囚人のジレンマ」が発生しやすく,共有資源の保全・管理は悲劇的な結末を迎える可能性が高い.出役と集落規模については,「ただ乗り」する者の排除不可能性とモニタリングにおける規模の経済を理由として,逆U字型の関係が先行研究によって指摘されているが,本稿の分析結果はそれと矛盾しない.

 The major objectives of this paper are to present hypotheses regarding collective action for irrigation management and to verify them empirically, based on data collected by the author in rural Yunnan, China. It turns out that the evolutionary game theory is very useful for this purpose. An econometric analysis corroborates these hypotheses by revealing that collective action will be forthcoming in a rural community, where few non-farm job opportunities are provided, the resource restriction is moderately problematic, farmland is frequently reallocated among households, the degree of income disparity among farmers is quite small, and the irrigation game is linked to a variety of social exchange games. In other words, communities that do not meet these conditions are likely to suffer from prisoner’s dilemma and the management of local commons ends in tragedy. The relationship between group size and collective action is ambiguously determined in our theoretical model, but there exists an inverse “U-shape” relationship, due to the imperfect exclusion and lumpiness in the technology of third-party monitoring.

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書誌情報Bibliographic information

Vol. 61, No. 4, 2010 , pp. 289-301
HERMES-IR(一橋大学機関リポジトリ): https://doi.org/10.15057/21989
JEL Classification Codes: C73, O13, Q25