Assistant Professor Colorado State University Fort Collins, Colorado
Pollinating insect populations are threatened by habitat loss and competition from non-native honeybees in urban settings, but city parks could be a crucial refuge. A park’s pollinator community is not only affected by the park’s management, but the surrounding neighborhood’s landscape. Of the 250 parks in Denver, Colorado, some are surrounded by affluent homes with lawns and gardens, but many are surrounded by apartments with limited greenspace. Considering this pattern, we hypothesize that pollinators are impacted by a “luxury effect”, where greater biodiversity is found in more affluent areas. In this study, we investigated how pollinator diversity differed across city parks depending on neighborhood income level, landscape factors, floral traits, and honeybee abundance. After visiting 25 city parks three times during the summer of 2023, we found that the most affluent parks had greater native bee biodiversity than their lower income counterparts, but the same trend did not hold for butterflies. Notably, less affluent parks hosted a greater proportion of non-native and weedy flower species, and we found a negative relationship between the proportion of weedy flower species and bee species richness, suggesting that the disparity in bee diversity among parks could be driven by the origin and diversity of available floral resources. Surprisingly, landscape characteristics of urban areas like impervious surface cover did not significantly impact bee or butterfly diversity, nor did honeybee abundance. These findings emphasize that managers should prioritize native floral plantings across urban park landscapes, thus improving pollination resources regardless of neighborhood income level.