Water, Air, and Soil Pollution

, Volume 85, Issue 4, pp 2413–2418

Nitrogen critical loads for natural and semi-natural ecosystems: The empirical approach

  • Roland Bobbink
  • Jan G. M. Roelofs
Part V Critical Loads

DOI: 10.1007/BF01186195

Cite this article as:
Bobbink, R. & Roelofs, J.G.M. Water Air Soil Pollut (1995) 85: 2413. doi:10.1007/BF01186195

Abstract

One of the major threats to the structure and the functioning of natural and semi-natural ecosystems is the recent increase in air-borne nitrogen pollution (NHy and NOx). Ecological effects of increased N supply are reviewed with respect to changes in vegetation and fauna in terrestrial and aquatic natural and semi-natural ecosystems. Observed and validated changes using data of field surveys, experimental studies or, of dynamic ecosystem models (the ‘empirical approach’), are used as an indication for the impacts of N deposition. Based upon these data N critical loads are set with an indication of the reliability. Critical loads are given within a range per ecosystem, because of spatial differences in ecosystems. The following groups of ecosystems have been treated: softwater lakes, wetlands & bogs, species-rich grasslands, heathlands and forests. In this paper the effects of N deposition on softwater lakes have been discussed in detail and a summary of the N critical loads for all groups of ecosystems is presented. The nitrogen critical load for the most sensitive ecosystems (softwater lakes, ombrotrophic bogs) is between 5–10 kg N ha−1 yr−1, whereas a more average value for the range of studied ecosystems is 15–20 kg N ha−1 yr−1. Finally, major gaps in knowledge with respect to N critical loads are identified.

Copyright information

© Kluwer Academic Publishers 1995

Authors and Affiliations

  • Roland Bobbink
    • 1
  • Jan G. M. Roelofs
    • 1
  1. 1.Department of Ecology, Researchgroup Environmental BiologyUniversity of NijmegenED NijmegenThe Netherlands

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