Rapid urbanisation is leading to devastating decreases in global biodiversity. While cities expand economic opportunities and foster diversity and inclusion for humans, the conversion of land into urban space is one of the primary drivers of biodiversity loss around the world. To develop cities that can provide habitats for all living species, we must better understand the influence of urbanisation on biodiversity. This study has two focuses: global insect biodiversity and London butterfly biodiversity, each in relation to the challenges presented to them by different urbanisation variables: impervious surface area, artificial light at night and land cover. These relationships were studied with regression analysis and modelled with generalised linear mixed effects models. At the global level, only certain land uses exerted a significant influence over changes in insect biodiversity, with signals from the urbanisation variables being too weak to draw any conclusions regarding their impact. In the London case study, butterfly species richness fluctuated significantly with changes in the value of each urbanisation variable, as well as changes in land cover. This study calls attention to the importance of context when studying urbanisation’s impact on insect biodiversity. Though drawing patterns at the global scale was largely precluded due to external variables, at the single-city level butterfly species richness was determined by both landscape and local conditions. This study contributes to building our understanding of how changes in the built and natural environment can impact biodiversity, a crucial piece of knowledge in our increasingly urban world.

Rapid urbanisation is leading to devastating decreases in global biodiversity. While cities expand economic opportunities and foster diversity and inclusion for humans, the conversion of land into urban space is one of the primary drivers of biodiversity loss around the world. To develop cities that can provide habitats for all living species, we must better understand the influence of urbanisation on biodiversity. This study has two focuses: global insect biodiversity and London butterfly biodiversity, each in relation to the challenges presented to them by different urbanisation variables: impervious surface area, artificial light at night and land cover. These relationships were studied with regression analysis and modelled with generalised linear mixed effects models. At the global level, only certain land uses exerted a significant influence over changes in insect biodiversity, with signals from the urbanisation variables being too weak to draw any conclusions regarding their impact. In the London case study, butterfly species richness fluctuated significantly with changes in the value of each urbanisation variable, as well as changes in land cover. This study calls attention to the importance of context when studying urbanisation’s impact on 2 insect biodiversity. Though drawing patterns at the global scale was largely precluded due to external variables, at the single-city level butterfly species richness was determined by both landscape and local conditions. This study contributes to building our understanding of how changes in the built and natural environment can impact biodiversity, a crucial piece of knowledge in our increasingly urban world.