Data from: Invasive forb benefits from water savings by native plants and carbon fertilization under elevated CO2 and warming

As global changes reorganize plant communities, invasive plants may benefit. We hypothesized that elevated CO2 and warming would strongly influence invasive species success in a semi‐arid grassland, as a result of both direct and water‐mediated indirect effects. To test this hypothesis, we transplanted the invasive forb Linaria dalmatica into mixed‐grass prairie treated with free‐air CO2 enrichment and infrared warming, and followed survival, growth, and reproduction over 4 yr. We also measured leaf gas exchange and carbon isotopic composition in L. dalmatica and the dominant native C3 grass Pascopyrum smithii. CO2 enrichment increased L. dalmatica biomass 13‐fold, seed production 32‐fold, and clonal expansion seven‐fold, while warming had little effect on L. dalmatica biomass or reproduction. Elevated CO2 decreased stomatal conductance in P. smithii, contributing to higher soil water, but not in L. dalmatica. Elevated CO2 also strongly increased L. dalmatica photosynthesis (87% versus 23% in P. smithii), as a result of both enhanced carbon supply and increased soil water. More broadly, rapid growth and less conservative water use may allow invasive species to take advantage of both carbon fertilization and water savings under elevated CO2. Water‐limited ecosystems may therefore be particularly vulnerable to invasion as CO2 increases.

• Resource Title: Supporting Information - Tables 1-5.

  File Name: Web Page, url: https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.12459#support-information-section

  Table S1 ANOVA results for effects of elevated CO2 and temperature on L. dalmatica biomass and reproduction.

  Table S2 ANOVA results for effects of elevated CO2 and temperature on L. dalmatica survival and growth.

  Table S3 ANOVA results for effects of elevated CO2 and temperature on photosynthesis (A), stomatal conductance (g), instantaneous water use efficiency (A/g) and the maximum rate of carboxylation (Vcmax) in L. dalmatica and P. smithii.

  Table S4 ANOVA results for effects of elevated CO2 and temperature on Δ13C for L. dalmatica and P. smithii.

  Table S5 ANCOVA results and regression coefficients for effects of elevated CO2, temperature, and soil water content on photosynthesis (A) and stomatal conductance (g), in L. dalmatica and P. smithii.

  Notes S1 CO2 and warming effects on soil volumetric water content.

  Notes S2 Evaluation of how transplanting may have influenced effects of elevated CO2 and warming on L. dalmatica.

  Fig. S1 Volumetric soil water content (VWC) at a depth of 5–25 cm averaged across the 4 months of maximum plant productivity (May–August), and monthly total precipitation.

  Fig. S2 Inorganic soil N in subplots with L. dalmatica and without.