Approaches to assess nitrogen impacts on ecosystems and environments - Challenges of towards International Nitrogen Management System (INMS) project

Hideaki Shibata, Field Science Center for Northern Biosphere, Hokkaido University, Sapporo, Japan, Hideaki Shibata, International Long-Term Ecological Research Network, Jill Baron and Timothy Weinmann, US Geological Survey, Fort Collins, CO, Jill Baron, Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO, Azusa Oita, Institute for Agro-Environmental Sciences, NARO, Tsukuba, Japan, Allison M. Leach, Natural Resource and Earth Systems Science and The Sustainability Institute, University of New Hampshire, Durham, NH, Daniel Liptzin, Soil Health Institute

Background/Question/Methods
The nitrogen cascade has multiple impacts on humans and nature. Globally, excess reactive nitrogen (Nr) in the environment has been recognized as one of the urgent global environmental exceedances of the current safe-operating capacity of our planet (i.e., the Planetary Boundary). As part of the Towards an International Nitrogen Management System (INMS) project, we developed a Guidance Document of Nr impact assessment methodology for human health and the environment. This Guidance Document describes the methods to assess the negative and positive impacts of Nr for various categories: human health, greenhouse gas balance, terrestrial and aquatic ecosystems, agricultural and non-agricultural products, and cultural services. We applied the DPSIR (Drivers, Pressures, States, Indicators and Responses) framework to identify key indicators and their relation to impacts for human health and environment qualities.
Results/Conclusions
The Guidance Document will describe integrated and specific assessment methodologies of multiple Nr impacts using current scientific knowledge regionally and globally. The target audience of this Guidance Document includes scientists and policymakers who can apply the nitrogen impact assessment methodologies. The complex impacts of Nr take place across multiple sectors, contexts, and scales, so we developed a comprehensive matrix of both positive and negative impacts linked to N cascades. The matrix includes 37 key indicators and their links to available global models on nitrogen flow, impact analysis and economic valuation. This is the first global comprehensive Nr impacts matrix and will be a useful foundation for interpreting model outputs and policy implications of Nr management.