Developing an approach for Sweden, Switzerland, United States and France for setting critical loads based on biodiversity including management, pollution and climate change

•We have a method that can make critical loads for nitrogen based on biodiversity across Europe and North America is available.•The ForSAFE-VEG model system considers the major drivers and the internal dynamics of ecosystems and it is operational on regional databases.•It passes the field test on observed plant ground cover composition.•Model improves communication between stakeholders and experts.•The policy development needs integrated assessment modelling in order to be able to develop meaningful policies with a chance to succeed.

The integrated dynamic ecosystem model ForSAFE-VEG was used to estimate critical loads for nitrogen using different chemical and biological criteria, and attempting to account for possible effects of climate change. The study is based on a model application on sites used for critical loads assessments in Sweden and France, focusing on the ecological effect of nitrogen pollution. To assess critical loads for nitrogen to ecosystems, two criteria were used for the critical loads estimates, N leaching, and changes in plant community composition, and assessed using the models mentioned. We show that the models give results consistent with earlier results using other methods such as the simple mass balance method. We show that the new model system is operational over the whole of the territory and may be used for policy development and policy outcome assessments.