Ecohydrology

Irrigated agriculture contributes significantly to the provisioning ecosystem services of food, feed, and fiber production, and can contribute other services under certain conditions. Irrigation systems vary greatly in terms of complexity, application method, water source, and governance. It is imperative to document the effect of irrigation systems on ecosystem processes and services and identify management practices that can provide multiple other benefits beyond agricultural production. Land use change such as urbanization, climate change effects such as reduced snowpack, and other drivers threaten traditional irrigation systems worldwide. In north-central New Mexico, United States, there are hundreds of unique community irrigation ditches called acequias, which have formed part of the landscape for generations. Our research has begun to document the influence of these systems on river basin and floodplain hydrology and riparian habitat. We found that acequia agriculture provides three key water-related regulating ecosystem services: shallow aquifer recharge, enhanced late-season streamflow, and maintenance and/or improvement of groundwater quality. Acequia irrigation also provides habitat services: through maintaining and often expanding riparian habitat, acequias can increase species habitat or at least mitigate habitat loss in other areas of the watershed. Acequia agriculture provides multiple cultural services, which can be lost under conversion of agricultural and riparian areas to urban and residential uses, thus also losing the associated regulating and supporting ecosystem services. Urban expansion and demand for water in the future will challenge the very survival of many acequias in the state. It seems likely that the more acequia communities can resist urban expansion, the more riparian areas and riparian functions supported by acequias will be protected from loss. We hope that the findings presented will stimulate continued research on multiple benefits of acequias as well as the development of management strategies that will allow irrigated agriculture to contribute to conserving critical habitat and optimizing the ecohydrologic function of agricultural systems.