Spatial planning as a tool for decreasing nitrogen loads in nature areas

Abstract

Deposition of nitrogen forms one of the largest threats to the vitality and biodiversity of Dutch nature areas. Of the two nitrogen compounds contributing to the total nitrogen deposition, Dutch sources of reduced nitrogen are estimated to contribute 47% to the total nitrogen deposition, whereas for oxidised nitrogen this is only 15%. For Dutch policy it is therefore most effective to decrease ammonia emissions. To safeguard the nature areas from ammonia deposition by limiting critical N load exceedances, a reduction of more than 70% of the ammonia emissions compared with the 1980 level is needed. Such a stringent target causes much friction between agriculture, the primary source of ammonia, on the one hand and nature conservation and development on the other. This friction is mainly caused by the fact that both the most sensitive natural areas in terms of acidification and eutrophication and the intensive agricultural areas are located on the poor sandy soils. When searching for solutions to the ammonia stress in natural areas it is necessary to look at possibilities of reducing emissions and thereby its effects, on the one hand, and at possibilities of disconnecting the spatial relationship between agriculture and nature, on the other. These two options have been addressed in this article and it is found that current policy on decreasing ammonia emissions is, even after disconnecting agriculture and nature, not enough to safeguard the nature areas. However, introducing specific functions for nature areas, thereby introducing higher critical loads, will provide the possibility for lower emission decreases than is needed for Dutch nature at present.