Urban Expansion and Butterfly Diversity: The Synergistic Effects of Impervious Surface and Vegetation Cover

Under the background of global urbanization, the impacts of urban expansion on biodiversity are becoming increasingly significant. Butterflies, as key ecological indicator species and important pollinators, are crucial for studying population dynamics and their driving factors in order to support biodiversity conservation and environmental governance. Butterflies also have important ecological value in urban biodiversity conservation and landscape maintenance. Currently, in many countries, especially developing countries, impervious surfaces and vegetation cover are undergoing significant changes as urbanization intensifies. Existing studies have begun to focus on the effects of these changes on biodiversity conservation. However, most studies primarily focus on the single effects of these two factors on biodiversity, while systematic assessments of their potential interactive effects remain limited. In this study, monthly butterfly population monitoring was conducted in Kunming, China, for two consecutive years. The study aimed to clarify the composition of butterfly diversity in Kunming and to explore the effects of impervious surfaces and vegetation cover on butterfly species richness, abundance, Shannon index, Simpson index, and community structure. The results showed that impervious surface was the primary driving factor influencing both butterfly richness and abundance, while the influence of vegetation cover was relatively limited. The Shannon and Simpson indices were not significantly influenced by either environmental factor. Environmental filtering caused by impervious surfaces and vegetation cover drove species turnover processes. Consequently, butterfly communities exhibited the highest heterogeneity in areas characterized by low impervious surfaces and high vegetation cover. In contrast, areas with high impervious surfaces and low vegetation cover tended to show a pattern of community homogenization. Urban planning should balance the control of impervious surface proportions with the appropriate enhancement of vegetation cover and plant diversity. Such measures may mitigate the negative impacts of intensified urbanization on butterfly diversity to some extent.