Atmospheric nitrogen deposition in world biodiversity hotspots: the need for a greater global perspective in assessing N deposition impacts |
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| Authors: | GARETH K PHOENIX W KEVIN HICKS† STEVE CINDERBY† JOHAN C I KUYLENSTIERNA† WILLIAM D STOCK‡§ FRANK J DENTENER¶ KEN E GILLER&#; AMY T AUSTIN ROD D B LEFROY†† BEN S GIMENO‡‡ MIKE R ASHMORE§§ PHILIP INESON¶¶ |
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| Institution: | Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK,;Stockholm Environment Institute, University of York, York, YO10 5DD, UK,;Centre for Ecosystem Management, Edith Cowan University, Joondalup 6027, Australia,;Department of Botany, University of Cape Town, Rondebosch 7701, Cape Town, South Africa,;Joint Research Centre, Institute for Environment and Sustainability, Climate Change Unit, TP280, I-21020 Ispra (Va), Italy,;Plant Production Systems Group, Department of Plant Sciences, Wageningen University, PO Box 430, 6700 AK Wageningen, The Netherlands,;IFEVA and Department of Ecology, Faculty of Agronomy and CONICET, University of Buenos Aires, Avenida San Martín 4453 (C1417DSE), Buenos Aires, Argentina,;Centro Internacional de Agricultura Tropical (CIAT), PO Box 783, Vientiane, Lao PDR,;Ecotoxicology of Air Pollution, CIEMAT. Ed 70. Avda Complutense 22, 28040 Madrid, Spain,;Environment Department and Stockholm Environment Institute, University of York, York, YO10 5DD, UK,;Department of Biology and Stockholm Environment Institute, University of York, York, YO10 5DD, UK |
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| Abstract: | Increased atmospheric nitrogen (N) deposition is known to reduce plant diversity in natural and semi‐natural ecosystems, yet our understanding of these impacts comes almost entirely from studies in northern Europe and North America. Currently, we lack an understanding of the threat of N deposition to biodiversity at the global scale. In particular, rates of N deposition within the newly defined 34 world biodiversity hotspots, to which 50% of the world's floristic diversity is restricted, has not been quantified previously. Using output from global chemistry transport models, here we provide the first estimates of recent (mid‐1990s) and future (2050) rates and distributions of N deposition within biodiversity hotspots. Our analysis shows that the average deposition rate across these areas was 50% greater than the global terrestrial average in the mid‐1990s and could more than double by 2050, with 33 of 34 hotspots receiving greater N deposition in 2050 compared with 1990. By this time, 17 hotspots could have between 10% and 100% of their area receiving greater than 15 kg N ha?1 yr?1, a rate exceeding critical loads set for many sensitive European ecosystems. Average deposition in four hotspots is predicted to be greater than 20 kg N ha?1 yr?1. This elevated N deposition within areas of high plant diversity and endemism may exacerbate significantly the global threat of N deposition to world floristic diversity. Overall, we highlight the need for a greater global approach to assessing the impacts of N deposition. |
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| Keywords: | Conservation endemics nitrogen deposition plant diversity pollution species loss |
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