Beta diversity of urban spontaneous plants and its drivers in 9 major cities of Yunnan province, China

•The exponent (z) of the SAC model was used in urban ecosystems to characterize beta diversity.•We found the species composition of native plants was more heterogeneous than non-natives.•The beta diversity of all species groups was best explained by alpha diversity and urbanization.•Urban spontaneous plants diversity was determined by both the current state and historical processes of urbanization.