Activity 1.6 Grasslands / Wetlands CarboEurope IP Ecosystem Component meeting Grassland/Wetland report Levi, 14-18/11 / 05

Months objectives Task 1.1 To assess the representativity of the grassland/wetland site network. Soil, climate, vegetation and management conditions of grassland and wetland sites will be compared to spatial distributions within Europe. Task 1.2. To analyse the NPP components of selected grassland/wetland main sites. To provide GPP, ecosystem respiration and light use efficiency estimates for these sites. Task 1.3. To calculate the NBP of grasslands/wetland sites, taking into account organic C imports and exports and assess with a simple model the role of management for annual NEE and NBP. Task 1.4. To parametrise and evaluate a detailed mechanistic grassland model. The (PASIM) model will be used with data from selected main grassland sites of the cluster network.

Grasslands/Wetlands activities Grassland / wetlands meeting in Paris (29/03/04) –«Measurements protocols and site management». The corresponding guidelines are available on the CarboEurope Web site. Specific issues for wetlands: Kaamanen meeting, Finland (22/06/04) Related meetings and activities: –Joined «CarboMont» and «GreenGrass» meeting in Trento, October A first synthesis of grassland results from these two FP5 projects, related to CarboEurope, has been delivered to the EC (DG XII and DG XI). –Global Carbon Project, Beijing November 2004 (J-F Soussana). –Fluxnet meeting, December 2004, Firenze (Tagir Gilmanov) –Special Study on Grasslands (SS3, CarboEurope GHG), published. –Ameriflux meeting (Tagir Gilmanov) –International Grassland Congress (J-F Soussana) –CarboEurope GHG final conference (J-F Soussana)

Data delivery and access to data Data delivery : 11 (/15) main sites and 1 (/13) ancillary site have uploaded the requested first set of data in –Need to discuss with the grassland/wetland group problems encountered by Main Sites which did not deliver their data yet. Quality check of the ecological data: just started Still some password problems for access to data basis We will discuss during grasslands/wetlands session issues related to the Paris/Kaamanen guidelines

Task 1.1 To assess the representativity of the grassland/wetland site network. Task 1.2. To analyse the NPP components of selected grassland/wetland main sites. Task 1.3. To calculate the NBP of grasslands/wetland sites. Task 1.4. To parametrise and evaluate a detailed mechanistic grassland model.

Main Grass. Anc. Grass. Relevant coverage of Western Europe Lack of Nordic and Eastern European sites

Sites vs. C storage potential at optimal N fertilization

Site representativeness Discussion in parallel session Questions: –Check non flux and management data delivery and potential problems –Can we improve site management and non flux measurements? –For each scientific question, which sites are essential? –How to parametrise and validate models for sectoral upscaling?

Task 1.1 To assess the representativity of the grassland/wetland site network. Task 1.2. To analyse the NPP components of selected grassland/wetland main sites. Task 1.3. To calculate the NBP of grasslands/wetland sites. Task 1.4. To parametrise and evaluate a detailed mechanistic grassland model.

Ecosystem-Scale Physiology Diurnal variations of photon flux density (Q) and corres-ponding variations on net daytime assimilation (P) allow to estimate daytime respiration as an intercept of the light-response curve (Marshall and Biscoe, 1980; Couston and Dale, 1990; Suyker and Verma, 2001). Ecosystem-scale light response curves for several European grassland sites nonrectangular hyperbolic model (Data source: CarboEurope CO 2 Flux Data Set)

Light-Temperature Response Functions For days with strong hysteresis of the P(Q) graph, daytime CO 2 exchange is better described by the two- factorial five-parametric nonrectangular hyperbolic model: Light-temperature response surfaces for: (a) Alinya 2004, Day 196; (b) Bugac 2003, Day 134; ( c ) Laqueuille ext 2003, Day 171; (d) Grillenburg 2004, Day 198 (CarboEurope CO 2 Flux Data Set) ab c d

Management Effects On Light-Use Efficiency Time-domain plot of mean weekly light-use efficiency LUE wk (t) for an extensively managed grassland at Oak Park, Ireland, Abrupt drops of LUE in the middle of the summer in 2002 and 2003 reflect hay mowing events.

Comparative Ecosystem-Scale Physiology

Parametric Portraits Of Grasslands A max - maximum average weekly maximum gross photosynthesis;  max - maximum average weekly apparent quantum efficiency; r day - maximum average weekly daytime respiration. Regressions on (a) are statistically different. Bermudagrass (Morgan et al. 1983)

Grassland GPP and RE versus Temperature There is no direct correlation between GPP and RE of grasslands and mean annual temperature.

Grassland GPP and RE Related to Precipitation

Grasslands - Sources or Sinks for CO 2 ? E. Odum’s plot for grassland ecosystems of the data set. Points below the dashed 1:1 line are sinks for atmospheric CO 2.

Task 1.1 To assess the representativity of the grassland/wetland site network. Task 1.2. To analyse the NPP components of selected grassland/wetland main sites. Task 1.3. To calculate the NBP of grasslands sites and assess the role of management. Task 1.4. To parametrise and evaluate a detailed mechanistic grassland model.

Components of the grassland carbon budget NEE: Net Ecosystem Exchange, Atmospheric C balance NBP: Net Biome Productivity, Soil C balance

Intake CH 4 Rani Rplant + Rsol GPP Reco LW increase Faeces Carbon fluxes in a continuously grazed site (g C m -2 yr -1 ) Intensive management – FR Laqueuille

Carbon fluxes in a cut grassland (CH-Oensingen)  C/  t CO 2 harvest manure

NBP is less than NEE in cut but not in grazed only sites Grazed only sites with no C input

Can we predict NEE from state variables and climate? GPP = PAR a * RUE PAR a = PAR i * (1-e -k*LAI ) LAI = SLA * W shoot RUE =RUEmax * f (T) * f (SW) Rp = Rref*Q10^((T-Tref)/10) Rref= W shoot * r leaf Rsoil = Rref_s * Q10_s^ ((T-Tref_s)/10) * f (SW) Rani = Stocking rate * r ani Gross assimilation Plant respiration Soil respiration Animal respiration

IntensiveExtensive Jan 2003 Dec 2003 Disentangling climate and management with a simple model: NBP components for Laqueuille site

Task 1.1 To assess the representativity of the grassland/wetland site network. Task 1.2. To analyse the NPP components of selected grassland/wetland main sites. Task 1.3. To calculate the NBP of grasslands/wetland sites. Task 1.4. To parametrise and evaluate a detailed mechanistic grassland model.

PASIM evaluation: errors for shoot biomass were reduced with model improvement (versions S0 to S3)

Using NEE components for PaSim evaluation

Disentangling climate and management effects Run all parametrised sites with a standardised management Test sensitivity of NEE and NBP to management and to management (mitigation) changes

Mitigation: stocking density - CO 2 Easter Bush (UK)

Upscale Pasim at a regional scale PaSim Hourly values of irradiance temperature pressure humidity. wind speed Climatology from ECMWF Grassland fractional coverage Combined CORINE. PELCOM Soil texture (Zoebler) Water content parameters (FAO) Climate drivers Land cover map Soil data dates of harvest. animal stocking rate and grazing periods. dates of application and amount of N- fertilizers Management drivers Equilibrium run at a spatial resolution of 1 degree GPP Respirations N2O emissions CH4 emissions … Model outputs Automatic optimal management module (Vuichard et al.) New run with statistics?

Planned integrated papers (old) 1.1 Valentini et al. Site representativity 1.2 Gilmanov et al. Grassland flux decomposition and climate sensitivity 1.3 Allard et al. Grassland management effects on NBP 1.4 Klumpp et al. Management vs. climate effects using PaSim model (+ Annette with EPIC) Wetlands modelling with Pixgro Soussana (?) et al. Synthesis of the grassland flux data (including the GreenGrass, Carbomont, CarboEurope sites) All papers with sites co-authors (when data are available)

Revised integrated papers and WP for months (Site representativity Valentini et al.) 6.1 Grassland flux decomposition and climate sensitivity (Gilmanov et al.) 6.2 Grassland management effects on NBP. Simple model to be closely linked with J. Tenhunen (Vincent Allard) 6.3 Contribution of past history, current management and climate effects for NEE, NBP and GHG balance using models (+Katja Klumpp with Pasim and Annette Freibauer with EPIC) 6.4 Wetlands modelling with Pixgro (John Tenhunen) 6.5 Synthesis of the grassland flux data (including the GreenGrass, Carbomont, CarboEurope sites) (J-F Soussana) All papers with sites co-authors (when data are available)