Reconciling climate change mitigation, biodiversity conservation and rice production through changes in water management strategies

Tackling climate change while enhancing biodiversity without compromising production is a main goal in agricultural policy. In rice farming, water-saving irrigation techniques alternative to permanent flooding are necessary to face water scarcity and have proven effective in reducing greenhouse gas (GHG) emissions, yet potential trade-offs with biodiversity conservation are often overlooked. Here we used a field-scale experiment to compare the effects of water management strategies representing a water use gradient on i) GHG emissions, ii) the diversity of aquatic macroinvertebrate and vertebrate (fish and amphibians) communities, and iii) crop productivity. Reduced methane emissions were observed in rice fields with lowest water use when compared to fields permanently flooded, yet the effect on aquatic biodiversity and crop yield was the opposite. Through this holistic assessment approach, we were able to identify an intermediate rice water-saving irrigation strategy that conciliates climate change mitigation, biodiversity conservation and crop production in rice agrosystems.