Nitrogen deposition in Spain: modeled patterns and potential implications for conservation

Evidences of an ongoing nitrogen enrichment of Spanish terrestrial ecosystems have been recently recorded. Atmospheric chemical transport models are valuable tools to identify those areas where these effects of atmospheric nitrogen deposition could be occurring. This study documents the performance of two chemical transport models (EMEP and CHIMERE) in predicting annual values of wet deposition of nitrogen and describes its main patterns for the period 2005-2008 in Spain. Wet nitrogen deposition was acceptably predicted by both models, showing better results for oxidized than for reduced nitrogen, particularly using the CHIMERE model. Dry nitrogen deposition may be underestimated, particularly by the EMEP model. Both models estimated higher wet deposition values in Northern and Northeastern Spain, decreasing along a NE-SW axis and ranging 1.2-13.3 and 1.0-8.7 kgN ha -1 y -1 for This is the author’s version of a work that was accepted for publication in Science of the total environment (Ed. Elsevier). Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in GarcíaGómez, H. et al. “Nitrogen deposition in Spain: modeled patterns and threatened habitats within the Natura 2000 network” in Science of the total environment, vol. 485-486 (2014), p.450-460. DOI 10.1016/j.scitotenv.2014.03.112 EMEP and CHIMERE model, respectively. Total nitrogen deposition (wet plus dry) in 2008 was used to calculate Critical Load exceedances within the Spanish Natura 2000 network (188,856.9 km 2 ). Threatened areas of 4521.4 and 1657 km 2 were predicted by CHIMERE and EMEP models, respectively. Grassland habitats proved to be the most threatened group, particularly in the Alpine Bio-geographical Region, pointing out that biodiversity conservation in these protected areas could be endangered.