Experimental and literature review of internationally proposed critical levels for ammonia to protect the vegetation : final report : final report comprising the state of the art and the results from an ammonia fumigation experiment and a field gradient study : final report / by Jürgen Franzaring, Julia Kösler (University of Hohenheim, Stuttgart) ; on behalf of the German Environment Agency ; report written by: University of Hohenheim, Institute of Landscape and Plant Ecology ; edited by: Section II 4.3 "Air Pollution and Terrestrial Ecosystems" - Markus Geupel (Fachbegleitung)

Abstract

Vascular plants, mosses and lichens react sensitively to the exposure to air pollutants and pollution from ammonia (NH3). Critical concentration values for ammonia to protect vegetation (so-called critical levels) were defined for risk assessment in the Geneva Convention on Long-Range Transboundary Air Pollution (CLRTAP). The project was used to review the current scientific status of those impact thresholds. In addition, extensive experimental studies were carried out to test the sensitivity of numerous native vascular plant species to NH3. The focus here was on species protected under the Natura2000 legislation and common in habitats in Germany.