Functional Relationships with N Deposition Differ According to Stand Maturity in Calluna-Dominated Heathland |
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Authors: | Alan Glyn Jones Sally A Power |
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Institution: | .Division of Biology, Imperial College London, Silwood Park, Ascot, Berkshire, SL5 7PY UK ;.University of Western Sydney, Hawkesbury Institute for the Environment, Locked Bag 1797, Penrith, NSW 2751 Australia ;.Earthwatch Institute, 256 Banbury Road, Oxford, OX2 7DE UK |
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Abstract: | Plant and soil bio(chemical) indicators are increasingly used to provide information on N deposition inputs and effects in a wide range of ecosystem types. However, many factors, including climate and site management history, have the potential to influence bioindicator relationships with N due to nutrient export and changing vegetation nutrient demands. We surveyed 33 heathlands in England, along a gradient of background N deposition (7.2–24.5 kg ha−1 year−1), using Calluna vulgaris growth phase as a proxy for time since last management. Our survey confirmed soil nutrient accumulation with increasing time since management. Foliar N and phosphorus (P) concentrations in pioneer- and mature-phase vegetation significantly increased with N deposition. Significant interactions between climate and N deposition were also evident with, for example, higher foliar P concentrations in pioneer-phase vegetation at sites with higher temperatures and N deposition rates. Although oxidized N appeared more significant than reduced N, overall there were more, stronger relationships with total N deposition; suggesting efforts to control all emissions of N (i.e., both oxidized and reduced forms) will have ecological benefits.Electronic supplementary materialThe online version of this article (doi:10.1007/s13280-014-0529-4) contains supplementary material, which is available to authorized users. |
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Keywords: | Habitat management Oxidized N Reduced N Lowland heathland Calluna growth phase Bioindicators |
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