title: Ecosystem responses to reduced and oxidised nitrogen inputs in European terrestrial habitats.
abstract: While it is well established that ecosystems display strong responses to elevated nitrogen deposition, the importance of the ratio between the dominant forms of deposited nitrogen (NH(x) and NO(y)) in determining ecosystem response is poorly understood. As large changes in the ratio of oxidised and reduced nitrogen inputs are occurring, this oversight requires attention. One reason for this knowledge gap is that plants experience a different NH(x):NO(y) ratio in soil to that seen in atmospheric deposits because atmospheric inputs are modified by soil transformations, mediated by soil pH. Consequently species of neutral and alkaline habitats are less likely to encounter high NH(4)(+) concentrations than species from acid soils. We suggest that the response of vascular plant species to changing ratios of NH(x):NO(y) deposits will be driven primarily by a combination of soil pH and nitrification rates. Testing this hypothesis requires a combination of experimental and survey work in a range of systems.
authors.affiliation: Department of Life Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK. c.j.stevens@open.ac.uk
authors.forename: Carly J
authors.initials: CJ
authors.lastname: Stevens
authors.forename: Pete
authors.initials: P
authors.lastname: Manning
authors.forename: Leon J L
authors.initials: LJ
authors.lastname: van den Berg
authors.forename: Maaike C C
authors.initials: MC
authors.lastname: de Graaf
authors.forename: G W Wieger
authors.initials: GW
authors.lastname: Wamelink
authors.forename: Andries W
authors.initials: AW
authors.lastname: Boxman
authors.forename: Albert
authors.initials: A
authors.lastname: Bleeker
authors.forename: Philippine
authors.initials: P
authors.lastname: Vergeer
authors.forename: Maria
authors.initials: M
authors.lastname: Arroniz-Crespo
authors.forename: Juul
authors.initials: J
authors.lastname: Limpens
authors.forename: Leon P M
authors.initials: LP
authors.lastname: Lamers
authors.forename: Roland
authors.initials: R
authors.lastname: Bobbink
authors.forename: Edu
authors.initials: E
authors.lastname: Dorland
mesh_terms: D017753:Ecosystem; D052918:Environmental Restoration and Remediation; D005060:Europe; D009584:Nitrogen / Q000737:chemistry / Q000378:metabolism*; D017672:Nitrogen Compounds / Q000737:chemistry / Q000378:metabolism*; D009589:Nitrogen Oxides / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D010944:Plants / Q000737:chemistry / Q000378:metabolism*; D012989:Soil Pollutants / Q000737:chemistry / Q000378:metabolism*
chemical_list: D017672:Nitrogen Compounds; D009589:Nitrogen Oxides; D012989:Soil Pollutants; D009584:Nitrogen