Examining effects of site level and landscape scale factors on butterfly communities in greenspaces across a rural-urban gradient

Insect communities around the world are facing threats from increasing human land-use, including urbanization and agricultural intensification. Habitat degradation has greatly impacted invertebrate pollinators, and butterfly species are no exception. Butterflies are especially sensitive to environmental change, most notably in the larval stage, and often serve as indicator species of ecosystems as a result. In order to help conserve butterfly communities in urban environments, this study aimed to examine how anthropogenic land-use affects butterfly abundance and diversity as well as their interactions with floral resources. To accomplish this, I surveyed butterflies and floral resources at twelve sites (six parks and six farms) in the metro-Detroit area. Then, I examined how several environmental attributes at the local and landscape scale influenced butterfly assemblages at these sites. Park sites supported higher butterfly diversity than farm sites. In addition, butterfly richness increased with greater urbanization, which may be explained by a higher concentration of floral resources within a generally more inhospitable urban matrix. Larger sites supported more larval specialists, whereas a greater amount of edge habitat was associated with more larval generalists. Finally, high native plant species richness positively influenced butterfly diversity. These findings indicate that butterfly conservation efforts in urban areas should focus on enlarging green spaces and supporting high-quality habitat edge with diverse native plant resources as well as increasing the abundance of plant resources that support larval specialist species.