Urban plants with different seed dispersal modes have convergent response but divergent sensitivity to climate change and anthropogenic stressors

Abstract

Spontaneous plants are crucial components of urban biodiversity. The distribution of spontaneous plants can be profoundly affected by their seed dispersal mode and environmental factors in urban systems. Since a comprehensive investigation into the drivers of successful seed dispersal modes of spontaneous plants is still lacking, we explored the impacts of natural factors, dispersal limitation, and habitat quality factors on the diversity pattern of spontaneous plants. We assessed the diversity patterns of four seed dispersal modes in 16 major cities in Yunnan province, the most biodiverse province in China. A total of 1,744 spontaneous plants of 916 genera and 175 families were recorded in 893 green patches. The dominating seed dispersal mode of urban spontaneous plants in most cities (13 out of 16) was autochory (33.5–38.7%), with hydrochory being least frequent (4.3–10.9%). Our research highlights spontaneous plants in heavily disturbed anthropogenic ecosystems, such as urban areas, tend to adopt convergent strategies to address environmental stressors. Their richness was significantly higher in colder and humid climates. However, as dispersal limitations (measured by distance to city boundary, city size and urbanization rate) increased and decrease in habitat quality (as expressed by patch area), the richness of all dispersal modes experienced a reduction. However, the sensitivities among different dispersal modes to these factors are divergent. Hydrochory exhibited the strongest sensitivity to habitat quality and climate factors. Whereas autochory demonstrated a strongest sensitivity, and anemochory showed a weakest sensitivity to dispersal limitation. These results suggest that include improving habitat quality or creating green corridors to mitigate dispersal limitation between urban areas and surrounding mountains will be valuable additions to urban biodiversity conservation efforts.