01496nas a2200133   4500008004100000245007100041210006900112300001100181490000600192520103500198100001801233700001501251856009601266       2006                        eng d00aNon-neutral patterns of species abundance in grassland communities0 aNonneutral patterns of species abundance in grassland communitie  a15 -230 v93 aAlthough 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*.1 aHarpole, W.S.1 aTilman, D.  uhttp://knz.lternet.edu/content/non-neutral-patterns-species-abundance-grassland-communities