JEG DM: common work items

• Targets & ex post analysis

• Robustness

• Links with biodiversity

• Trends in selected modeled/measured parameters

JEG DM: Targets & ex-post

1. Two aspirational targets for 2050 that should be incorporated into policy: no further enrichment of nitrogen (N) in soils resulting from atmospheric deposition, and no further depletion of base cations from soils resulting from atmospheric deposition.

2. Target loads have been developed at the European scale. CIAM should undertake at least one run of optimization based on target loads.

JEG DM: Robustness

3. The lack of base cation deposition estimates remained problematic for the dynamic models on ecological impact.

4. For the revision of the 1999 Gothenburg Protocol, dynamic models must take climate change and related policies into account in predictions, as they systematically change the rate of key processes. As a consequence, current predictions with dynamic models might be too pessimistic.

JEG DM: Links with biodiversity

5. At N limited ecosystems N deposition leads to C sequestration. But, at very high N deposition plant growth is reduced. Biomass productivity could also be limited by other factors (e.g., trace nutrients, water, energy). Need further research on those factors.

6. Developments on model systems such as VSD+ and SPECIES; VEGontoVSD; BERN model; ForSAFE-VEG. We need a comparative study of the parameterization of the different models.

JEG DM: Links with biodiversity

7. Need to quantify existing biodiversity targets in relation to the model outputs.

8. Need to develop biological models to assess the impact of N as a nutrient for aquatic ecosystems. Need to enhance those aquatic models with internal process feedbacks related to climate change and land management.

9. We need data from sites with long-term records (decades) to evaluate and test dynamic models.

JEG DM: Trends

JEG has nothing to report

JEG 11 (Oct 27 – 29 2010, Sitges)

• planned call for data 2010/2011

• DM of N as a nutrient in terrestrial systems

• DM of climate change/air pollution interactions, terrestrial carbon sequestration

• DM of biological response

Contact Susie Beresford (sjbe@ceh.ac.uk)

Agenda items include

JEG DM

Acidification, Nitrogen as a nutrient and Heavy Metals

JEG DM: Acidification

•Acidification is considered, but current DM efforts seldom on acidification only

•There still is a room for further emission cuts of acidifying air pollutants. Dynamic models have provided arguments to continue efforts to reduce emissions.

Modelling nutrient N – major concern of JEG DM

• Major efforts are being undertaken to understand, document and model changes of plant communities by several strong research groups in a number of countries

• JEG provides discussion platform for modellers

• CCE plays major role in this development

JEG DM: nutrient N•Increasing trends in DOC are probably linked to recovery from acidification.

•There were still uncertainties in understanding and modelling of N cycling. Some general trends were well predicted, but short-term variations still represented challenges at individual sites.

•The carbon-to-nitrogen ratio (C/N) of soil organic matter was one of the few indicators with some utility in predicting the ecosystem response to changing deposition, land use or climate.

JEG DM: nutrient N

•The carbon-to-nitrogen ratio (C/N) of soil organic matter was one of the few indicators with some utility in predicting the ecosystem response to changing deposition, land use or climate

•further development of DM of N not to use C/N to predict N leaching is necessary and is being undertaken

JEG DM: heavy metals• 15. Metal accumulation and leaching could be approximately explained by deposition, weathering, speciation, soil acidity and run-off. DM difficult to validate due to the slow responses.

• 16. The leaching of Ni, Zn and Cd from soils responded relatively rapidly (decades) while Cu, Pb and Hg responded more slowly (centuries). Key controls included metal deposition, acidity status and soil organic matter.

JEG DM: heavy metals• 17. Nevertheless, JEG emphasized the importance of ensuring that policy continued to control the release of metals into the environment. Release of heavy metals from soil was a long-term process and that should not detract from efforts to reduce emissions.