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Determinants of species richness in the Park Grass experiment

Crawley, M.J.; Johnston, A.E.; Silvertown, J.; Dodd, M.; de Mazancourt, C.; Heard, M.S.; Henman, D.F. and Edwards, G.R. (2005). Determinants of species richness in the Park Grass experiment. American Naturalist, 165(2) pp. 179–192.

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The Park Grass Experiment at Rothamsted in southeast England was started in 1856, making it the longest-running experiment in plant ecology anywhere in the world. Experimental inputs include a range of fertilizers (nitrogen, phosphorus, potassium, and organic manures) applied annually, with lime applied occasionally, and these have led to an increase in biomass and, where nitrogen was applied in the form of ammonium sulfate, to substantial decreases in soil pH. The number of species per plot varies from three to 44 per 200 m2, affording a unique opportunity to study the determinants of plant species richness and to estimate the effect sizes attributable to different factors. The response of species richness to biomass depends on the amount and type of nitrogen applied; richness declined monotonically with increasing biomass on plots receiving no nitrogen or receiving nitrogen in the form of sodium nitrate, but there was no relationship between species richness and biomass on plots acidified by ammonium sulfate application. The response to lime also depended on the type of nitrogen applied; there was no relationship between lime treatment and species richness, except in plots receiving nitrogen in the form of ammonium sulfate, where species richness increased sharply with increasing soil pH. The addition of phosphorus reduced species richness, and application of potassium along with phosphorus reduced species richness further, but the biggest negative effects were when nitrogen and phosphorus were applied together. The analysis demonstrates how multiple factors contribute to the observed diversity patterns and how environmental regulation of species pools can operate at the same spatial and temporal scale as biomass effects.

Item Type: Journal Item
Copyright Holders: 2005 The University of Chicago
ISSN: 1537-5323
Keywords: coexistence; competitive exclusion; species-area relationship; nitrogen; phosphorus; acidification herbaceous plant-communities; diversity; productivity; biomass; biodiversity; patterns; density; ecosystem; competition; limitation
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM) > Environment, Earth and Ecosystem Sciences
Faculty of Science, Technology, Engineering and Mathematics (STEM)
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Item ID: 2295
Depositing User: Jonathan Silvertown
Date Deposited: 12 Jun 2006
Last Modified: 08 Dec 2018 13:08
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