Understanding robustness to distubance through the theory of the commons: Irrigation water governance and socio-ecological robustness in the Gallego and Cinca River Watersheds, Spain

This research contributes to understanding how local communities organize in response to social and ecological threats by studying a set of more than 100 irrigation systems in Spain. The main research questions are: How do different institutions and socio-ecological attributes affect the ability of Spanish irrigation systems to cope with different disturbances? How do attributes of the disturbances affect the robustness of the irrigation systems?;The research consist of three studies: (1) a case study of the historical ability that an ensemble of state-promoted irrigation systems have developed to cope with droughts; (2) a statistical study of drought performance across those irrigation systems; and (3) a comparative case study of the responses that 2 of those systems and 3 other systems have developed to cope with a variety of disturbances over the last two decades.;According to the case study, seven configurations of resource, governance and actor properties can help to understand the robustness of the ensemble of state-promoted irrigation systems to droughts. The most relevant properties within those configurations are a high storage capacity, a hierarchical structure of clear and collective water rights, a strong administrative leadership and a linkage of rights and duties of farmers to landownership. According to the statistical study, leadership, monitoring and flexible property rights have a positive effect on drought performance while group size and collective choice do not. The effect of leadership and property rights is mediated by rules at higher governance levels, pointing to the importance of taking into account multi-level dynamics. According to the comparative case study, one of the most consistent paths to robustness among the 5 systems under study involves the concurrent effect of leadership, collective choice and cross-scale linkages given the context of small or homogeneous systems. Also, robustness to intense and frequent disturbances like droughts tends to rely on the role of leaders, while robustness to progressive and/or infrequent disturbances like rural depopulation depends on a wider set of conditions.;Overall, the results show the relevance of using and adapting the theory of the commons to develop middle-range theories of robustness in local water management contexts.