Conclusion

This study indicates that naturalized species have higher levels of climatic suitability than cultivated plants that have not naturalized. However, under a warmer climate, naturalized species are predicted to lose mostly equal areas with suitable climates as cultivated plants that did not naturalize yet. Therefore, as climate change progresses, we might see a turnover in the composition of the naturalized species pool. The study also reveals that plants with different native origins and biomes in southern Africa are affected differently. These findings can assist in identifying cultivated alien plants that pose invasion risks early and in developing effective management strategies to mitigate their impacts. Our study highlights that the potential distribution of the cultivated alien flora in Southern Africa is unlikely to be amplified by future climate changes. On the contrary, climatically suitable ranges are projected to shrink, particularly under severe climate change. The main reason for this finding is that climate change will likely result in increasingly hot, semi-arid climates in the region, which will impose strong constraints on the survival of many plant species; accordingly, many native species are projected to experience shrinking in climatically suitable space in the region. Thus, our study highlights that increased climatic suitability for alien species under climate change, which seems to be the norm in cold and temperate climates, does not necessarily translate to similar results in regions of the subtropics.