Effect of Native and Non-Native Plantings in Urban Parking Lot Islands on Diversity and Abundance of Birds, Arthropods, and Flower Visitors

Abstract

Redesigning urban landscapes so that they better support biodiversity has the potential to reduce well-documented losses of pollinators and birds. This study tested whether small-scale native and nonnative ornamental urban plantings affect either arthropod or bird diversity. Birds, floral visitors, and arthropod diversity were monitored in six parking lot islands landscaped with native plants and six parking lot islands with non-native ornamental plantings on the Indiana University South Bend campus located in South Bend, St. Joseph County, Indiana. Higher bird species richness and four times higher bird abundance was observed in parking lot islands with native plantings compared to non-native plantings. Abundance of flower visitors was significantly higher in native areas compared to non-native areas. There was no significant difference in arthropod order richness between the two types of parking lot islands. However, arthropod abundance was significantly higher in native plantings compared to non-native ornamental plantings. Overall, including native plants in small-scale landscaping increases biodiversity by supporting higher abundances of arthropods, flower visitors, and birds.