Nitrogen critical loads using biodiversity-related critical limits.
Critical loads are widely used in the effects-based assessment of emission reduction policies. While the impacts of acidification have diminished, there is increasing concern regarding the effects of nitrogen deposition on terrestrial ecosystems. In this context much attention has been focussed on empirical critical loads as well as simulations with linked geochemistry-vegetation models. Surprisingly little attention has been paid to adapt the widely used simple mass balance approach. This approach has the well-established benefit of easy regional applicability, while incorporating specified critical chemical criteria to protect specified receptors. As plant occurrence/biodiversity is related to both the nutrient and acidity status of an ecosystem, a single abiotic factor (chemical criterion) is not sufficient. Rather than an upper limit for deposition (i.e., critical load), linked nutrient nitrogen and acidity chemical criteria for plant occurrence result in an 'optimal' nitrogen and sulphur deposition envelope.
Coordination Centre for Effects, PBL, PO Box 303, 3720 AH Bilthoven, The Netherlands. max.posch@pbl.nl
Maximilian
M
Posch
Julian
J
Aherne
Jean-Paul
JP
Hettelingh
D044822:Biodiversity; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods*; D058735:Environmental Policy; D004785:Environmental Pollutants / Q000032:analysis*; D004787:Environmental Pollution / Q000706:statistics & numerical data; D006863:Hydrogen-Ion Concentration; D009584:Nitrogen / Q000032:analysis*
D004785:Environmental Pollutants; D009584:Nitrogen