Data from: Elevated ozone promotes the dominance of invasive plant species in low-diversity native plant communities

Premise of the study: The diversity-invasibility hypothesis suggests that native plant communities with high species diversity are more resistant to invasions by exotic species compared to those with fewer species. This resistance stems from more complete resource use and stronger biotic interactions in diverse communities, which limit opportunities for invaders to establish. However, this resistance could potentially be weakened by environmental stressors, including elevated tropospheric ozone. Ozone levels have increased globally from 10-15 ppb in pre-industrial times to around 50 ppb today. Elevated ozone affects plant species differently, depending on their functional traits and physiological tolerances. Yet, no prior study has tested how elevated ozone affects the link between native plant community diversity and invasion resistance. To investigate this, we conducted an open-top chamber experiment to assess the impact of ozone enrichment on invasive plant growth in native communities of differing species richness.Methods: We established 16 native plant communities: eight low-diversity and eight high-diversity. Each community was invaded by a single individual from one of nine exotic species and grown under either ambient (40.72 ppb) or elevated (83.10 ppb) ozone.Key results: Elevated ozone reduced the mean above-ground biomass of invasive species by 9.64% overall. The decline was greater in low-diversity communities (-18.46%) than in high-diversity ones (-12.54%). Elevated ozone enhanced the mean proportional above-ground biomass of invasive species in low-diversity communities (11.24%), but not in high-diversity communities.Conclusions: These findings support the diversity-invasibility hypothesis and suggest that species-rich communities maintain stronger invasion resistance even under elevated ozone conditions.