Dias, TeresaMalveiro, SóniaChaves, SandraTenreiro, RogérioBranquinho, CristinaMartins-Loução, Maria AméliaSheppard, LucyCruz, Cristina2011-09-152011-09-152011Hicks WK, Whitfield CP, Bealey WJ, Sutton MA (eds.) Nitrogen Deposition and Natura 2000- Science & practice in determining environmental impacts (Book of Proceedings of the COST729 Mid-term workshop).978-91-86125-23-3http://hdl.handle.net/10451/4108Although Mediterranean-type ecosystems are biodiversity hotspots, very little is known about the effects of increased N availability in these systems; This paper describes an integrated field study on the effects of increased N availability in a Mediterranean-type ecosystem in a Natura 2000 site in Portugal; The ecosystem was highly N responsive: visible changes were seen within one year; N additions created new and distinct seasonal patterns of soil N availability; plant and soil bacterial diversity together with plant cover were increased; The effects of increased N availability appeared to depend on N form - plant evenness; N dose - plant species richness; and on both N form and dose - species cover and soil bacterial richness.engbook part