Critical loads of nitrogen and sulphur to avert acidification and eutrophication in Europe and China
2015
Posch, Maximilian | Duan, Lei | Reinds, Gert Jan | Zhao, Yu
INTRODUCTION: Forests and other (semi-)natural ecosystems provide a range of ecosystem services, such as purifying water, stabilizing soils and nutrient cycles, and providing habitats for plants and wildlife. Critical loads are a well-established effects-based approach that has been used for assessing the environmental consequences of air pollution on large regional or national scales. MATERIALS AND METHODS: Typically critical loads of sulphur (S) and nitrogen (N) have been derived separately for characterizing the vulnerability of ecosystems to acidification (by S and N) and eutrophication (by N). In this paper we combine the two approaches and use multiple criteria, such as critical pH and N concentrations in soil solution, to define a single critical load function of N and S. RESULTS AND CONCLUSIONS: The methodology is used to compute and map critical loads of N and S in two regions of comparable size, Europe and China. We also assess the exceedance of those critical loads under globally modelled present and selected future N and S depositions. We also present an analysis, in which the sensitivity of the critical loads and their exceedances to the choice of the chemical criteria is investigated. As pH and N concentration in soil solution are abiotic variables also linked to plant species occurrence, this approach has the potential for deriving critical loads for plant species diversity.
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