Nutrient addition shifts plant community composition towards earlier flowering species in some prairie ecoregions in the U.S. Central Plains

Authors

Lori A. Biederman, Iowa State UniversityFollow
Brent Mortensen, Iowa State University
Philip Fay, USDA-ARSFollow
Nicole Hagenah, University of KwaZulu-Natal
Johannes M. H. Knops, University of Nebraska-LincolnFollow
Kimberly J. La Pierre, University of California - Berkeley
Ramesh Laungani, Doane CollegeFollow
Eric Lind, University of MinnesotaFollow
Rebecca McCulley, University of KentuckyFollow
Sally Power, Western Sydney University
Eric W. Seabloom, University of MinnesotaFollow
Pedro Tognetti, Universidad de Buenos Aires

Document Type

Article

Date of this Version

5-26-2017

Citation

Biederman L, Mortensen B, Fay P, Hagenah N, Knops J, La Pierre K, et al. (2017) Nutrient addition shifts plant community composition towards earlier flowering species in some prairie ecoregions in the U.S. Central Plains. PLoS ONE 12(5): e0178440. https://doi.org/ 10.1371/journal.pone.0178440

Comments

Open Access.

Abstract

The distribution of flowering across the growing season is governed by each species' evolutionary history and climatic variability. However, global change factors, such as eutrophication and invasion, can alter plant community composition and thus change the distribution of flowering across the growing season. We examined three ecoregions (tall-, mixed, and short-grass prairie) across the U.S. Central Plains to determine how nutrient (nitrogen (N), phosphorus, and potassium (+micronutrient)) addition alters the temporal patterns of plant flowering traits. We calculated total community flowering potential (FP) by distributing peakseason plant cover values across the growing season, allocating each species' cover to only those months in which it typically flowers. We also generated separate FP profiles for exotic and native species and functional group. We compared the ability of the added nutrients to shift the distribution of these FP profiles (total and sub-groups) across the growing season. In all ecoregions, N increased the relative cover of both exotic species and C₃ graminoids that flower in May through August. The cover of C₄ graminoids decreased with added N, but the response varied by ecoregion and month. However, these functional changes only aggregated to shift the entire community's FP profile in the tall-grass prairie, where the relative cover of plants expected to flower in May and June increased and those that flower in September and October decreased with added N. The relatively low native cover in May and June may leave this ecoregion vulnerable to disturbance-induced invasion by exotic species that occupy this temporal niche. There was no change in the FP profile of the mixed and short-grass prairies with N addition as increased abundance of exotic species and C₃ graminoids replaced other species that flower at the same time. In these communities a disturbance other than nutrient addition may be required to disrupt phenological patterns.