Divergent responses of plant growth forms to climate and urban expansion

Urbanization and climate change are rapidly altering large-scale plant distributions and local community compositions, profoundly impacting ecosystem functions and services. However, it remains unclear how life form compositions, one of the key functional biodiversity components, respond jointly to urbanization and climate gradients. Here we investigated the life form compositions of 2,864 naturally regenerated spontaneous plant species across 129 cities in Yunnan province of China, a global biodiversity hotspot with diverse environmental condition. Our results showed perennial herbs (45.0%) predominated in urban ecosystem, followed by annual herbs (29.2%) and woody plants (25.8%). Bayesian hierarchical models revealed that as urban expansion, the proportions of annual herbs rise, while the proportions of both perennial herbs and woody plants decline, indicating urban expansion favors short-lived plants but is detrimental to long-lived plants. Increasing mean annual temperature with a decline in perennial herbs and a concurrent increase in woody plants, suggesting divergent adaptive responses to thermal stress. Our results highlight the complex, divergent responses of plant life forms to urbanization and climate change, emphasizing the need for targeted conservation strategies that consider both the resilience of short-lived species and the vulnerability of long-lived plants.