OZONE CRITICAL LEVELS FOR MEDITERRANEAN FORESTS

Transcription

1 OZONE CRITICAL LEVELS FOR MEDITERRANEAN FORESTS R. Alonso, G. Gerosa, Á. Ribas, V. Calatayud, M. Díaz de Quijano, S. Elvira, E. Calvo, R. Marzuoli, J. Peñuelas, F. Bussotti, M. Pollastrini, S. Mereu, L. Fusaro, I. González-Fernández

2 Concentration-based critical levels (AOT40) Air Quality Directive 2008/50/CE (EEA, 2010) <=5000 ppb.h ppb.h ppb.h ppb.h > ppb.h Forests CLe_c: AOT40=5000 ppb.h 5% biomass reduction Sensitive species: birch, beech Countries: Sweden, Finland, Switzerland Mediterranean areas: > ppb.h 11-20% biomass reduction expected

3 Flux-based critical levels (POD) Phytotoxic Ozone Dose Revision i of Gothenburg Protocol to Abate Acidification, Eutrophication and Ground-level Ozone (2010) Picea abies Norway spruce POD 1 = 8 mmol m -2 PLA 2% anual biomass reduction Fagus sylvatica Betula pendula beech birch POD 1 = 4 mmol m -2 PLA 4% annual biomass reduction EUFORGEN Networks

4 Objectives: -Test the current ozone critical levels for Mediterranean forest species - If neccesary, suggest new ozone critical levels for Mediterranean forest species

5 Review of experiments Mediterranean species growing under Medit. climate Experiments with growth/biomass data Species Exposure system Location O 3 treatments Other treatments gs measurem Quercus ilex OTC Ebro Delta (Spain) CFA, NFA, NFA years OTC Ebro Delta (Spain) CFA, NFA, NFA+40 WW/DS OTC Valencia (Spain) CFA, NFA OTC Curno (Italy) CFA, NFA+ salt OTC Curno (Italy) CFA, NFA+ salt Quercus coccifera OTC Ebro Delta (Spain) CFA, NFA, NFA+40 WW/DS Ceratonia siliqua OTC Ebro Delta (Spain) CFA, NFA, NFA OTC Ebro Delta (Spain) CFA, NFA, NFA Olea europaea OTC Ebro Delta (Spain) CFA, NFA, NFA OTC Ebro Delta (Spain) CFA, NFA, NFA Arbutus unedo OTC Ebro Delta (Spain) CFA, NFA, NFA OTC Curno (Italy) CFA, NFA+ salt OTC Curno (Italy) CFA, NFA+ salt Pinus halepensis OTC Ebro Delta (Spain) CFA, NFA, NFA+40 WW/DS Pinus uncinata Open exposure Switzerland Control,O3+, O

6 Characteristics of the datasets available: Evergreen species: broadleaf and conifers All experiments with seedlings in pots Most of the experiments multiannual All but one with control treatment of filtered air Analysis of data: - Growing season: the whole year - % reduction of biomass related to control treatment - Ozone exposure/flux of the control subtracted from all treatments: control treatment set to zero - Multiannual experiments: total ozone exposure/flux total ozone exposure/flux divided by nº years - Fluxes calculated following the Mapping Manual for sunlit leaves: F = C(z) g r F st = C(z) g sto r c r b +r c

7 Exposure-response function 1.1 ive effect % relat 1.0 all 0.9 Q.ilex Q.coccifera 0.8 Olea Ceratonia 0.7 A.unedo P. halepensis 0.6 P. uncinata R 2 = Lineal (all) AOT40 of the experiment

8 Exposure-response function Only experiments with AGB data 1.1 ive effect % relat 1.0 all 0.9 Q.ilex Q.coccifera 0.8 Olea Ceratonia 0.7 A.unedo P. halepensis 0.6 P. uncinata R 2 = 0.35 Lineal (all) AOT40 of the experiment

9 Current CL e_c 5000 ppb.h 6 months 1,1 Exposure-response function Only experiments with AGB data ive effect % relat 1,0 all 0,9 Q.ilex Q.coccifera 0,8 Olea Ceratonia 0,7 A.unedo P. halepensis 0,6 P. uncinata R 2 = 0,40 Lineal (all) 05 0,5 0, % effect ppb.h AOT40 / year AOT40= ppb.h (5 months) Deciduous species (Calatayud et al., 2011) No effects on AGB! (effects in roots)

10 Exposure-response function Only experiments with AGB data % relative effect 5% effect ppb.h AOT40 / year 5% ppb.h

11 Modelling stomatal conductance DO 3 SE g sto = g max * f phen * f light * max {f min,(f temp * f VPD * f SWP )} (Jarvis, 1976; Emberson et al., 2000; UNECE, 2004) Species Local gs parameterization g max Mapping Manual parameterization g max Quercus ilex Quercus ilex 295 Quercus coccifera Quercus ilex 285 Ceratonia siliqua Generic Met. evergreen 285 Olea europaea Generic Met. evergreen 285 Arbutus unedo Generic Met. evergreen 285 Pinus halepensis Pinus halepensis 285 Pinus uncinata Pinus halepensis 350

12 Exposure vs. Dose response functions experiments with drought stress Pinus halepensis Rela ative AGB R 2 = R 2 = AOT40 POD Quercus ilex subsp. ilex & ballota 1.1 Relative e AGB R 2 = R 2 = AOT40 POD 0

13 Dose-response function Only experiments with AGB data 1.1 ive effect % relat 1.0 all 0.9 Q.ilex Q.coccifera 0.8 Olea Ceratonia 0.7 A.unedo P. halepensis 0.6 P. uncinata R 2 = 0.38 Lineal (all) POD 1 / year (mmol m -2 )

14 Dose-response function Current POD mmol m -2 Only experiments with AGB data 6 months 1.1 ive effect % relat 1.0 tall Q.ilex 0.9 Q.coccifera 0.8 Olea Ceratonia 0.7 A.unedo P. halepensis 0.6 P. uncinata R 2 = 0.38 Lineal (all) POD 1 / year (mmol m -2 ) 5% effect 19 mmol m -2 POD 1 up to 42.6 mmol m -2 (5 months) Deciduous species (Calatayud et al., 2011) No effects on AGB! (effects in roots)

15 Dose-response function Only experiments with AGB data % relative effect R 2 =0.38 p< % effect 19 mmol m -2 POD 1 / year (mmol m -2 ) 5% 33 mmol m -2

16 Dose-response function Only experiments with AGB data 1.1 % re elative eff fect R 2 = 0.38 all Qilex Q.ilex Q.coccifera Olea Ceratonia A.unedo P. halepensis P. uncinata Lineal (all) Local gs parameterization Y= x % reduction POD 1 = 19 mmol m -2 % 1 10% reduction POD 1 = 55 mmol m tive effec ct % rela R 2 = 0.54 all Q.ilex Q.coccifera Olea Ceratonia 0.7 A.unedo POD 1 / year (mmol m -2 ) P. halepensis P. uncinata Lineal (all) Mapping Manual parameterization Y= x % reduction POD 1 = 18 mmol m -2 10% reduction POD 1 = 42 mmol m -2

17 Exposure-response Dose-response 5% biomass reduction MM CLe_c: AOT40= ppb.h Norway spruce beech birch POD1= 8 mmol m-2 PLA 2% anual biomass reduction POD 1 = 4 mmol m -2 PLA 4% annual biomass reduction Mediterranean forests 5% biomass reduction Evergreen: ppb.h Evergreen: POD 1 = 19 mmol m -2 ( ppb.h) (POD 1 = 33 mmol m -2 ) Deciduous: oaks ppb.h Deciduous: oaks Calatayud et al., 2011 Karlsson et al., 2004 POD 1.6 = 16 mmol m -2 Calatayud et al., 2011 beech > ppb.h POD 1.6 = 12 mmol m -2 Ferreti et al., 2007 Karlsson et al., 2004

18 Conclusions: Levels of ozone frequently registered in Mediterranean areas are suficient to cause chronic changes Effects better related to fluxes than to AOT40 when there is drought stress Mediterranean forest species seem to be more tolerant to ozone: evergreen more than deciduous BUT more research is needed Current proposed flux-based critical levels for European forests would protect Mediterranean forests but they would overestimate the effects over large areas

19 Questions: How do we consider effects of multi-annual experiments? CL should be the average over several years for Mediterranean forests Which indicators perform best? Maybe AGB or growth not so important, vigor or vitality are more important for foresters (photosynthesis? respiration? sapwood area?) Can we establish a CL below the significance of the experimental results? If we protect crops and semi-natural vegetation, do we protect forests too? Annual grasslands are more O 3 -sensitive than forests! Different CL for different regions in Europe

20 THANK YOU! Acknowledgements: Cargas y Niveles Críticos, MARM Consolider-MONTES, MICINN EDEN, MICINN AGRISOST, Com. Madrid ECLAIRE- EU FP7