Anthropogenic activities can negatively impact the major shifts in butterfly functional diversity in semi-natural ecosystems. However, little is known about their functional trait diversity, rather than total species richness, driven by forest fragmentation and urbanization. In the present study, we evaluated whether forest fragmentation and urbanization affects the functional diversity and stability of butterfly assemblages. Regarding the anthropogenic impacts on butterfly biodiversity loss, we predicted that the functional diversity and temporal stability of butterfly species would increase with increasing area of fragmented forests, and that they would be higher in the rural areas than in the urban areas. The present study demonstrated that butterfly functional diversity and stability of species composition were maintained in the presence of larger forest remnant and less urbanized areas. In particular, the uni-voltine species and species overwintering during the egg-pupa stage were significantly negatively affected by forest fragmentation. We emphasized that future studies should use multi-functional traits of insect species to evaluate the impact of human activities on insect declines, as past studies may have overlooked this significant key for assessing species vulnerability and ecological adaptations under human activities.

The dataset was collected during 1999-2005 at Kanazawa City, located in the temperate region of Japan. This study has been reviewed in Biology letters.

The readme file contains an explanation of each of the variables in the dataset (species richness, environmental variables), and its measurement units (line and site). How to measure these data can be found in the manuscript.