Visible foliar symptoms as a proxy of ozone impact on vegetation: from the multi species approach of the ICP Forests method applied on European scale to the single bioindicator species approach
(1) Fondazione Edmund Mach, San Michele a/A, Italy (2) Forestry and Game Management Research Institute, Czech Republic (3) Slovenian Forestry Institute (4) Fundación CEAM, Paterna, Spain (5) Swiss Federal Research Institute WSL, Birmensdorf, Switzerland (6) National Institute for Research and Development in Forestry “Marin Drăcea” (INCDS), Romania
Tropospheric ozone (O3) is a strong oxidant phytotoxic pollutant that can cause a variety of detrimental effects on vegetation at a biochemical, physiological, and morphological level. Ozone leaves no elemental residue measurable by analytical techniques, but ozone-induced visible foliar symptoms (VFS), instead, represent a direct, specific, and easily detectable evidence of ozone effect on vegetation. VFS, largely observed and reproduced under controlled and semi-controlled conditions, can be considered as a proxy for the actual O3 damage on vegetation. A Standardized Operational Protocol was developed within the UNECE International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests), to collect high quality and comparable data on ozone-induced visible injury on native vegetation at the intensive Level II forest monitoring sites. The standardized method is based on the assessment of VFS on the native woody plants present in n=13-33 2 x 1 m quadrates randomly selected along the forest edge closest to a Level II forest monitoring site. The method, largely applied across Europe on overall 225 sites in 20 countries since 2002, aims to assess the risk posed by ozone on vegetation, and allows the detection of spatial and temporal trends of the effect of ozone on forests in Europe. The ICP Forests method, with minor changes, has been applied also to detect the effects of ozone on single species identified as particularly sensitive to this atmospheric pollutant. This is the case with the studies carried out on the native Viburnum lantana species, from the local scale within the same vegetative season, to the regional and larger scale on a pluriannual basis. Overall, results support the use of V. lantana as in-situ bioindicator to assess the harmful effect of O3 on vegetation. Provided a large-scale test-phase will confirm the local-to-regional scale results, the single-species approach could complement the ICP Forests program.
Keywords: Air quality; Tropospheric ozone; Ozone impact; Visible foliar symptoms; Ozone bioindicator
