Keynote Presentations from the 2nd AVEC International Summer School, Peyresq, 18-30 September 2005

Speaker: Mark Sutton
Atmospheric Sciences Centre for Ecology and Hydrology (CEH) (Edinburgh Research Station), Bush Estate, Penicuik, Midlothian, Scotland, UK, EH26 0QB

Title of the talk: Landscape variability and impacts of ammonia in relation to the Habitats Directive (pdf: 20MB)

Summary of the talk by Thomas Koetz: Students´ summary


Assessing the landscape level variability and impacts of atmospheric ammonia in relation to the EU Habitats Directive

Atmospheric ammonia is an air pollutant with both local, regional and international impacts. Much attention has focused on developing the science to develop international policies to reduce the transboundary pollution aspects. This has required the development of mapped emission inventories, atmospheric chemistry, transport and deposition models, and models for thresholds of expected ecological effects.

These developments represent a success story for science-policy interaction. For example, the signing of the Gothenburg Protocol and the National Emission Ceilings Directive represent the first time that international emission controls on ammonia have been agreed. By contrast, it is recognized that these agreements are not enough, and that more needs to be done to reduce emissions to levels that do not exceed, so called "critical loads" above which damage to habits occur. There are many effects, but the most relevant one for terrestrial ecosystems is that extra nitrogen from deposited ammonia favours nitrophytic plant species at the expense of ones succeeding under oligotrophic (nutrient limited) conditions.

One of the main failings of these agreements is that they are based on e.g. 50 km resolution maps, and miss the landscape level variability in ammonia emisssions and deposition. The main source of ammonia emission is livestock agriculture, so that the sources occur in rural landscapes in intimate mixture with the receiving ecoystems, such as forests, semi-natural grasslands and bogs. Nearness to source (e.g. 0-2 km) introduces a huge spatial variability in the deposition and exceedance of the critical loads. Explict GIS emission-dispersion models with a 20 m - 50 m resolution show that the exceedances are so large that it is realistically impossible to protect all ecosystems across Europe while maintaining livestock agriculture in its present form.

If it is accepted that not all ecosystems can be protected, the debate shifts to identify the priorities for protection from atmospheric deposition. A major point here to consider is the existence of the Habitats Directive, which gives an extremely high degree of protection to sites designated as Special Areas of Conservation (SACs) and Special Protection Areas (SPAs). Article 6 (3) of the habitats directive provides for a precautionary approach where the onus is on developers to demonstrate that there would be no adverse effect on these sites. This leads to a new thinking on ammonia abatement which focuses on spatial planning of agricultural activities in rural landscapes. It raises questions like: how wide should atmospheric buffer zones be? Can trees be used sacraficially to help recapture emissions? How can one prove that there will be no adverse effect of a development? How can agriculture be brought into the planning process? The seminar will finish with a case study of a recent Planning Appeal on whether to permit a new poultry farm adjacent to a heathland SAC.

Recommended background literature on this presentation:

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