Climate modifies response of non-native and native species richness to nutrient enrichment

Authors: FLORES-MORENO, HABACUC - University Of Minnesota; REICH, PETER - University Of Minnesota; LIND, ERIC - University Of Minnesota; SULLIVAN, LAUREN - University Of Minnesota; SEABLOOM, ERIC - University Of Minnesota; YAHDJIAN, LAURA - Universidad De Buenos Aires; MACDOUGALL, ANDREW - University Of Guelph; REICHMANN, LARA - University Of Texas; ALBERTI, JUAN - Consejo Nacional De Investigaciones Científicas Y Técnicas(CONICET); BAEZ, SELENE - Universidad Technologica Indoamerica, Biocamb, Machala Y Sabarilla; BAKKER, JONATHAN - University Of Washington; CADOTTE, MARC - University Of Toronto; CALDEIRA, MARIA - University Of Lisbon; CHANETON, ENRIQUE - Universidad De Buenos Aires; D'ANTONIO, CARLA - University Of California; Fay, Philip; FIRN, JENNIFER - Queensland University Of Technology; HAGENAH, NICOLE - University Of Kwazulu-Natal; HARPOLE, STANLEY - Helmholtz Centre For Environmental Research; IRIBARNE, OSCAR - Consejo Nacional De Investigaciones Científicas Y Técnicas(CONICET); KIRKMAN, KEVIN - University Of Kwazulu-Natal; KNOPS, JOHANNES - University Of Nebraska; LA PIERRE, KIMBERLY - University Of California; LAUNGANI, RAMESH - University Of Nebraska; LEAKEY, ANDREW - Desiderio Finamore Veterinary Research Institute (FEPAGRO); MCCULLEY, REBECCA - University Of Kentucky; MOORE, JOSLIN - Monash University; PASCUAL, JESUS - Consejo Nacional De Investigaciones Científicas Y Técnicas(CONICET); BORER, ELIZABETH - University Of Minnesota

Submitted to: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2016
Publication Date: 9/13/2016
Publication URL: http://handle.nal.usda.gov/10113/63141
Citation: Flores-Moreno, H., Reich, P.B., Lind, E.M., Sullivan, L.L., Seabloom, E.W., Yahdjian, L., MacDougall, A.S., Reichmann, L., Alberti, J., Baez, S., Bakker, J.D., Cadotte, M.W., Caldeira, M.C., Chaneton, E.J., D'Antonio, C., Fay, P.A., Firn, J., Hagenah, N., Harpole, S., Iribarne, O., Kirkman, K.P., Knops, J.M., La Pierre, K.J., Laungani, R., Leakey, A.D., McCulley, R.L., Moore, J.L., Pascual, J., Borer, E.T. 2016. Climate modifies response of non-native and native species richness to nutrient enrichment. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 371:20150273. doi:10.1098/rstb.2015.0273.

Interpretive Summary: Increases in the amount of nutrients in ecosystems, termed eutrophication, affects which plant species are most abundant in plant communities, and may favor increased abundance of invasive exotic species at the expense of native species. The extent to which eutrophication may favor invasive species over natives likely depends on climate, but the relative importance of climate means compared to year-to-year and seasonal climate variability remain poorly understood. This study helps fill this knowledge gap by revealing the importance of nitrogen, phosphorus, and potassium additions and climate variability on invasive species abundance at 32 grassland sites on four continents. A key strength of this study is that all 32 sites performed identical experiments studying the effects of these nutrients. The study found that nutrient addition increased invasive species abundance regardless of climate, and more so at cooler and drier sites, where the number of plant species in grassland communities become increasingly affected by year-to-year climate variation. This research clarifies how increased nutrient inputs affect grassland plant communities and supports efforts to suppress the spread of invasive exotic species by identifying climatic conditions where nutrients most increase invasive species abundance.

Technical Abstract: Ecosystem eutrophication often increases domination by non-natives and causes displacement of native taxa. However, variation in environmental conditions may affect the outcome of interactions between native and non-native taxa in environments where nutrient supply is elevated. We examined the interactive effects of eutrophication, climate variability and climate average conditions on the success of native and non-native species using experimental nutrient manipulations replicated at 32 grassland sites on four continents. We hypothesized that effects of nutrient addition would be greatest where climate was stable and benign, due to reduced niche partitioning. We found that the abundance of non-native species increased with nutrient addition independent of climate; however, nutrient addition increased non-native species richness and decreased native species richness, with these effects dampened in warmer or wetter sites. Thus, climatic conditions may modify responses of native and non-native flora to nutrient enrichment. Our results suggest that the negative effect of nutrient addition on native abundance is decoupled from its effect on richness. Importantly, eutrophication altered the time-scale in which grasslands respond to climate, decreasing the importance of long-term climate and increasing that of annual climate, perhaps from the increase in dominance of nonnative (often short-lived) species.