Balancing nitrogen retention ecosystem services and greenhouse gas disservices at the landscape scale

The “water quality maintenance function” of landscape features such as riparian zones has long been recognized as an important ecosystem service. More recently, concerns have emerged about side effects of ecosystem “disservices,” especially greenhouse gas production, associated with landscape approaches to agricultural nutrient management. Here we suggest that several decades of landscape scale research provide a strong platform for comprehensive assessment of ecosystem services and disservices associated with this management. Using N2O production disservices associated with nitrogen removal services as an example, we first describe some key concepts and challenges to our ability to connect sources and sinks of nitrogen in the landscape and to comprehensively assess the greenhouse gas implications of landscape nitrogen management. We then present a case study of how information on nitrogen sources and sinks (ponds, riparian zones, low order stream channels) in a landscape can be used as a platform for assessing N2O production and other ecosystem disservices at the landscape scale. While these disservices are highly variable and difficult to quantify, results suggest that factors such as soil and sediment texture, oxygen, and nitrate levels influence fluxes in a systematic way that should allow for the development of assessment and accounting protocols to account for ecosystem services and disservices associated with nitrogen flows in complex landscapes.