Short communicationNew stomatal flux-based critical levels for ozone effects on vegetation
Section snippets
Introduction and background
Tropospheric or ground-level ozone pollution has increased significantly over the last 100 years (Vingarzan, 2004) with current and future effects on health, ecosystems and vegetation being of considerable concern (Royal Society, 2008). For example, a recent study indicated that in Europe over 30 crop and 80 (semi-)natural vegetation species growing in 16 countries showed visible injury symptoms and other negative effects of ambient ozone such as biomass/yield reduction in the period of
The stomatal flux model used for the flux-based critical levels
Stomatal flux of ozone for an upper canopy sun-lit leaf is modelled using a multiplicative algorithm adapted from Emberson et al. (2000a) that incorporates the effects of air temperature (ftemp), vapour pressure deficit of the air surrounding the leaves (fVPD), light (flight), soil water potential (fSWP) or plant available water content (fPAW), plant phenology (fphen) and ozone concentration (fozone) on the maximum stomatal conductance (gmax, mmol O3 m−2 PLA s−1), i.e. the stomatal conductance
Agricultural crops
The flux-based critical levels are applicable for assessing the impacts of ozone on food security via affects on food availability and stability of food supplies. Flux-based response functions for effects of ozone on wheat (grain yield, protein yield and grain mass), potato (tuber yield), tomato (fruit yield), oilseed rape (oil content, seed yield), broccoli (floret yield), lettuce (biomass) and bean (pod yield) were reviewed. Approved for the derivation of critical levels were the functions
Supporting evidence, sources of uncertainty and further research
For each receptor, confidence is gained from the coherent pattern in response when combining experiments from different countries with different climatic conditions, and for crops for a range of varieties (Table 1). These functions had a similar level of significance to those using AOT40 as the ozone parameter (LRTAP Convention, 2010, Pleijel et al., 2007, Karlsson et al., 2007). However, the more biologically meaningful flux-based method provided a better fit to mapped data than AOT40,
Conclusion
In this paper we have provided an overview of the new/revised flux-based critical levels that have been agreed for use in assessment of risk of damage to crops, forest trees and (semi-)natural vegetation within the LRTAP Convention region. These critical levels and associated functions can be used to quantify impacts on food security, ecosystem services provided by forest trees, and the vitality of grasslands by following the guidance provided in LRTAP Convention (2010). Despite the
Acknowledgements
Gina Mills, Harry Harmens and Felicity Hayes wish to thank Defra (contracts AQ0810, AQ0816 and AQ0601), the LRTAP Convention and NERC for continued financial support of the coordination of the ICP Vegetation, and all the participants of the ozone group of the ICP Vegetation for their contributions to the review of the critical levels. Lisa Emberson and Patrick Büker would like to thank Defra for funding their research (contract AQ0601). The work by Håkan Pleijel, Per-Erik Karlsson and Helena
References (33)
- et al.
Use of sap flow measurements to validate stomatal functions for mature beech (Fagus sylvatica) in view of ozone uptake calculations
Environmental Pollution
(2010) - et al.
Comparison of different stomatal conductance algorithms for ozone flux modelling
Environmental Pollution
(2007) - et al.
Reactive uptake of ozone at simulated leaf surfaces: implications for ‘non-stomatal’ ozone flux
Atmospheric Environment
(2009) - et al.
Modelling stomatal ozone flux across Europe
Environmental Pollution
(2000) - et al.
Assessing the risk caused by ground level ozone to European forests: a case study in pine, beech and oak across different climate regions
Environmental Pollution
(2007) - et al.
Modelling of stomatal conductance and ozone flux of Norway spruce: comparison with field data
Environmental Pollution
(2000) - et al.
Impacts of ozone pollution on productivity and forage quality of grass/clover swards
Atmospheric Environment
(2008) - et al.
Meta-analysis of the relative sensitivity of semi-natural vegetation species to ozone
Environmental Pollution
(2007) - et al.
Effects of ozone on biomass partitioning and photosynthetic efficiency and capacity of Lolium perenne and Trifolium repens
Environmental Pollution
(2009) - et al.
Temporal processes that contribute to nonlinearity in vegetation responses to ozone exposure and dose
Atmospheric Environment
(2009)
Risk assessments for forest trees: the performance of the ozone flux versus the AOT40 concepts
Environmental Pollution
New critical levels for ozone effects on young trees based on AOT40 and simulated cumulative leaf uptake of ozone
Atmospheric Environment
Comparison of modelled and measured ozone concentrations and meteorology for a site in south-west Sweden: implications for ozone uptake calculations
Environmental Pollution
The challenge of making ozone risk assessment for forest trees more mechanistic
Environmental Pollution
A critical review and analysis of the use of exposure- and flux-based ozone indices for predicting vegetation effects
Atmospheric Environment
Ozone exposure-response relationships for mixtures of perennial ryegrass and white clover depend on ozone exposure patterns
Atmospheric Environment
Cited by (204)
Can fertilization OF CO<inf>2</inf> heal the ozone-injured agroecosystems?
2024, Atmospheric Pollution ResearchA three-year free-air experimental assessment of ozone risk on the perennial Vitis vinifera crop species
2023, Environmental PollutionStem growth of Norway spruce in south Sweden in relation to soil moisture, nitrogen deposition, ozone exposure and meteorological variables
2023, Forest Ecology and ManagementArbuscular mycorrhizal symbiosis alleviates ozone injury in ozone-tolerant poplar clone but not in ozone-sensitive poplar clone
2023, Science of the Total Environment