Environmental heterogeneity across habitats within a tropical urban landscape influences butterfly community compositions

Abstract

Increasing urbanisation and rapid climate change are causing organisms to redistribute across environments. However, the specific factors that influence local spatial community or population dynamics are often elusive, and even less is known about the impact of tropical urban landscapes on diverse species assemblages. In this study, we used a survey dataset with 510 fruit-feeding butterflies comprising 20 species to address this knowledge gap. To understand the butterfly community dynamics in the context of the daily environmental changes across two heterogenous habitats within a city in Nigeria, we assess species abundance, richness, and diversity indices along the thirty-six (36) spots where butterflies were sampled spanning two habitats, a savannah woodland and a gallery forest. We constructed generalised linear models to understand the differential responses of the butterfly community to daily changes in environmental conditions across habitats. Fruit-feeding butterflies’ diversity, richness, and abundance significantly differed between the two urban habitats, with butterfly species diversity, richness, and abundance being significantly higher in the savannah woodland when compared to the gallery forest. Furthermore, we found that butterfly community richness increased in the savannah woodland due to the warmer daily temperatures. In contrast, butterfly richness decreased in the gallery forest due to extreme environmental conditions. Thus, our study highlights that butterfly community changes in tropical urban landscapes may be shaped in response to changes in microclimates and spatial heterogeneity across habitats, with savannah woodland habitats, despite being the more open habitat types, may be serving as a refuge to certain butterfly species.