Differences in phenology between non‐native C4 grasses and native C3 and C4 grasses in a seasonally dry ecosystem

Plant species phenology is an important driver of invasions in seasonal climates.The phenology of non-natives is generally uncoupled from that of native species.Grasses cover a large proportion of the land surface and are important invadersaround the world. Interestingly, the phenology of native and non-native grassescould be modulated by the different metabolic pathways. We aimed to comparethe vegetative and reproductive phenology of invasive C₄ grasses with that ofcoexisting native C₃ and C₄ grasses and to explore the relationship betweenphenology and climate. We recorded the onset, duration and synchronicity ofvegetative and reproductive phenology (flowering and fruiting) during 1 year.Native C₃ grasses had 50% of their above-ground biomass green earlier andremained in that state for a longer period than non-native and native C₄ grasses.Flowering and fruiting occurred earlier in non-native C₄ grasses than in nativeC₄ grasses. The flowering period was longer in non-native C₄ than in native C₃and C₄, with the non-native Melinis repens (Poaceae), a highly invasive speciesworldwide, accounting for most of the difference. Non-native C₄ tended toexhibit a lower flowering and fruiting synchrony than both native C₃ and C₄ species.Finally, reproductive and vegetative phenology was positively associatedwith temperature, while precipitation was mostly associated with C₄ species. Theuncoupled vegetative phenology observed could be related to differences in metabolismamong the studied species, while the uncoupled reproduction between non-nativeand native C₄ grasses could be due to an advantage in resource use by non-nativespecies. Our work provides the first insight into the possible role of the species origin and metabolic pathways in the vegetative and reproductive phenology of invasive non-nativeC₄ and native C₃ and C₄ grasses. Finally, we suggest future directions to elucidate these processes.