Pollinator gardening is constrained by income but not lot size in urban front yards

Abstract

Flower gardens can create valuable habitat for urban pollinators, but little is known about the existing spatial pattern of gardens on the landscape, or factors associated with the decision to plant a flower garden. We mapped the distribution of front yard flower gardens compared to four other front yard landscaping types (lawn, shrubs, non-vegetated, and weeds) across 86,429 addresses in Greater Boston, MA, USA using Google Street View. We complemented these data with on-the-ground surveys at a stratified random subset of 519 yards. We hypothesized that census tracts with higher incomes would have higher flower garden frequencies and that these gardens would have higher species richness, and that census tracts with larger lots would also have higher flower garden frequencies and species richness. Yards identified as flower gardens using Google Street View contained around double the cultivated floral species richness of lawns and more than any other yard type. However, flower gardens were infrequent in front yards, and were a substantial front yard cover type in only 2.3 % of yards. Flower garden frequency and cultivated species richness were greater with higher census tract income, both consistent with the luxury effect hypothesis. However, higher-income lots also had more lawns and fewer spontaneous (weedy) species. Surprisingly, flower gardens had higher frequencies in census tracts with smaller lots. In our region, flower gardening appears to be constrained by income or education but not lot size, pointing to the potential role of small urban lots as a target for pollinator habitat.