Taters, trout, and/or trees? Understanding landscape scale tradeoffs among ecosystem services and using critical zone science to evaluate the effectiveness of artificial recharge to create synergies.

Management of agricultural landscapes has long required consideration of the tradeoffs among food production, water quantity/quality and ecosystem health. We argue that the science to inform these management decisions should account for feedbacks using an integrated approach and that the rapidly developing field of critical zone science has underexploited potential to inform decision making in agroecosystems. We use the Central Sands Region of Wisconsin as an exemplar to explore the tradeoffs and potential synergies that could result from managed aquifer recharge. For decades, irrigation using groundwater pumped from an unconfined glacial aquifer has supported a robust potato and vegetable industry in the region. However, the agricultural use of groundwater has led to groundwater depletion that has subsequently impacted aquatic and terrestrial ecosystems. Baseflow reduction impacted high quality trout fisheries while lowered groundwater levels decreased the groundwater subsidy to forests, altering climate-tree growth relationships and reducing productivity as indicated by tree ring analysis. To evaluate the regional impacts on groundwater storage, baseflow to fisheries, and forest productivity, we modeled changes to the groundwater flow regime and the resultant ecosystem services under managed aquifer recharge scenarios. Groundwater modeling reveals the strong extent to which the location of focused recharge affects the partitioning of groundwater storage, baseflow contributions or forest productivity benefits as well as the magnitude and spatial extent of these effects. Management decisions on whether and where to pursue managed aquifer recharge schemes should consider the leverage exerted on each of these ecosystem services and their associated societal and environmental values.