TERRESTRIAL ECOSYSTEM SENSITIVITY TO ACIDIC DEPOSITION IN DEVELOPING-COUNTRIES

Acidic deposition is considered a problem in Europe and North America but the potential for ecosystem damage from this pollution is also inc reasing rapidly in many developing countries. It is therefore importan t to assess current and future risks of ecosystem effects due to acidi c deposition in these areas. It is possible to indicate risk areas by linking an assessment of sensitivity to net acidic input rates derived from deposition estimates for sulphur and nitrogen compounds and base cations. A method to assess and map a relative scale of terrestrial e cosystem sensitivity using international datasets is presented. The as sessment relies on the determination of buffering mechanisms that prev ent effects related to acidic deposition. Land-cover data, edaphic and climate datasets are combined using a GIS. Large areas are assessed a s highly sensitive to acidic deposition in tropical regions of Asia, S outh and Central America and Africa, and also in the Boreal forests of northern Asia. Sensitive areas cover forest and non-forest ecosystems and some areas of agricultural production. Critical loads are not eva luated in this project but initial estimates will be applied to sensit ivity classes at a further stage which will allow estimation of areas at risk by comparison with deposition.