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Non‐neutral patterns of species abundance in grassland communities
Author(s) -
Stanley Harpole W.,
Tilman David
Publication year - 2006
Publication title -
ecology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.852
H-Index - 265
eISSN - 1461-0248
pISSN - 1461-023X
DOI - 10.1111/j.1461-0248.2005.00836.x
Subject(s) - abundance (ecology) , grassland , relative species abundance , ecology , relative abundance distribution , monoculture , habitat , biology , niche , neutral theory of molecular evolution , species diversity , niche differentiation , ecological niche , competition (biology) , plant community , species richness , biochemistry , gene
Although the distribution of plant species abundance in a Minnesota grassland was consistent with neutral theory, niche but not neutral mechanisms were supported by the ability of species traits to predict species abundances in three experimental grassland communities. In particular, data from 27 species grown in monoculture showed that species differed in a trait, R *, which is the level to which each species reduced the concentration of soil nitrate, the limiting soil nutrient and which is predicted to be inversely associated with competitive ability for nitrogen (N). In these N‐limited habitats, species abundance ranks correlated with their predicted competitive ranks: low R * species, on average dominated. These correlations were significantly different than expected for neutral theory, which assumes the exchangeability of species traits. Additionally, we found that changes in relative abundance after environmental change (N‐addition or disturbance) were not neutral but also were significantly associated with R *.