Community traitscape of foliar nitrogen isotopes reveals N availability patterns in a tallgrass prairie

Craine, Joseph M.; Towne, E Gene; Ocheltree, Troy W.; Nippert, Jesse B.

Community traitscape of foliar nitrogen isotopes reveals N availability patterns in a tallgrass prairie

2012

Craine, Joseph M. | Towne, E Gene | Ocheltree, Troy W. | Nippert, Jesse B.

BACKGROUND AND AIMS: Nutrients are important determinants of community assembly, yet the roles they play in structuring plant communities are still poorly understood. One inferential approach to understanding how environmental factors structure plant communities is examining the distribution of key functional traits among species of a community—a community traitscape. METHODS: To better understand how nitrogen (N) and water availability structure grasslands, we measured N concentrations and isotope ratios for 366 herbaceous species in a mesic N-limited temperate grassland, Konza Prairie. We also compared foliar N concentrations and N isotopes between Konza species and a global dataset. RESULTS: Species that had either high foliar N concentrations or high δ15NL were not necessarily more or less abundant on the landscape nor more or less likely to be found in uplands, grazed areas, or burned areas. Apparently there are unique hot spots of high N availability at Konza and the typical non-Fabaceae Konza species occupies sites with greater N availability than found globally. CONCLUSIONS: Although nascent, the Konza traitscapes suggest that plant diversity in nutrient-limited communities might be strongly dependent on high-nutrient availability sites that enable high-fertility species to persist in a matrix of low nutrient availability.

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