Landscape Context Influences the Abundance and Richness of Native Lady Beetles Occupying Urban Vacant Land

Abstract

Urban insect communities are structured by hierarchical filters including regional processes, human facilitation, and species interactions. We sought to inform future urban conservation endeavors by identifying how landscape composition and configuration as well as the management of vacant lot greenspaces affect native lady beetle (Coccinellidae) community structure within the city of Cleveland, Ohio, USA. We found no effect of habitat treatment on native lady beetle abundance when comparing vacant lots seeded with native wildflowers and those with naturally occurring weedy vegetation mown monthly or annually. Nonetheless, establishing conservation plantings that vary in plant height, biomass, and bloom abundance could aid in supporting a greater richness of coccinellid species, as these variables had differential effects on the abundance of fungivorous and aphidophagous feeding guilds. Further, we found that vacant lots embedded within landscapes with increased impervious surface and a high degree of greenspace isolation contained fewer aphidophagous native and exotic lady beetles. Our findings suggest that landscape context is a critical consideration when aiming to utilize vacant land as conservation habitat for coccinellids. Given their large holdings of vacant land, shrinking cities offer a unique opportunity to incorporate landscape-scale planning into future sustainable development initiatives. For instance, with over 27,000 vacant lots, the city of Cleveland could aid lady beetle conservation by electing to maintain vacant lots that promote greenspace connectivity while targeting isolated lots within intact neighborhoods for new residential development.