Landscape plants in major Chinese cities: Diverse origins and climatic congruence vis-à-vis climate change resilience

Cities have become the main abodes for people, and landscape plants with their notable influence on quality of life, are important components of the urban ecosystem. The need to explore the climatic suitability and sustainability of landscape plants is especially relevant due to globalization and climate change. Nevertheless, this research area is constrained by the limited understanding of the biogeographical origin of landscape plants. We have compiled data on species lists, taxonomic information, and geographical and climatic origins for woody landscape plants in 36 major cities across China. We used climatic niche breadth (CNB) and climatic mismatched ratio (CMR) to assess the climatic suitability and sustainability of landscape plants. We found that 412 alien species had several hotspots of origin, mainly tropical regions in the Americas, Asia, and Australia. The 1258 domestic species mainly originated from temperate southern China. Tropical species had a conspicuous geographical clustering in coastal cities of southern China, while the temperate species were abundant in all cities. The CNBs of domestic species were wider than those of alien species, and arid cities with harsher environmental stresses (mainly due to the limited precipitation) registered higher CMRs. In terms of sustainability, the response of landscape plants to climate change varied across climate zones, being influenced by a rich presence of temperate species. Overall, our findings emphasized that landscape plant selections should not only pay attention to the existing landscape needs, but also consider the climatic sustainability of landscape plant species to climate change, especially for long lifespan woody plants.