Critical loads are mapped for habitats sensitive to acidification and/or eutrophication. Therefore information on the the spatial distribution and area of habitats is required to map critical loads. The distributions of terrestrial habitats are mapped at 1x1 km resolution based on the CEH Land Cover Map 2000 and refined using ancillary data sets on species distributions, vegetation classification data and 1x1 km soil maps. Freshwaters are mapped for the 1752 lake and stream catchments included in this work. Further details on the methods and data used to map the habitat distributions, and their relationships to the habitat classes of the European Nature Information System (EUNIS) can be found in Hall et al. (2015).
It should be noted that the habitat distribution maps and areas used for UK critical loads (acidity, nitrogen) research (a) only include areas where data exist for the calculation or derivation of critical loads; (b) may differ from other national habitat distribution maps or estimates of habitat areas. This may also result in a difference in the total habitat areas mapped for acidity and nutrient nitrogen critical loads.
These show the acidity critical loads for soils, and the acidty critical loads (as represented by CLmaxS, CLminN, CLmaxN) and nutrient nitrogen critical loads by habitat type, based on the habitat distributions above.
The latest maps of exceedance of acidity and nutrient nitrogen critical loads, for all habitats combined, can be seen here.