Date on Senior Honors Thesis


Document Type

Senior Honors Thesis

Degree Name




Degree Program

College of Arts and Sciences

Author's Keywords

Urbanization; Pollinators; Pollinator Conservation; Native Plant Gardens; Urban Gardens; Caterpillar Models


Human impact on the environment is responsible for the sixth mass extinction on Earth as well as rapid population declines in many taxa. Land use change, via increasing urbanization and intensity of agricultural practices, is the most important aspect of human impact on the environment, and it is associated with population decline and extinction in several taxa, but especially in pollinator species. Pollinators, which are essential for crop production, are experiencing declines as a result of the loss of habitat and host plants associated with urbanization. Urbanization negatively affects pollinators, but in the wake of lost naturalized habitat, some researchers are turning to urban native plant gardens as conservation spaces for pollinator populations. The current study examines whether urban native plant gardens have higher rates of predation on pollinator species as compared to naturalized ecosystems. To determine this, we chose 24 garden sites in Louisville, KY along an urban-suburban gradient. We placed clay caterpillar models on the plants within these gardens and as the models were attacked, we categorized the resulting damage according to predator taxon. Although amount of predation did not vary with urbanization, the proportion of damage by each predator taxon did: wasp predation rates increased with increasing urbanization, while vertebrate and spider predation rates decreased with increasing urbanization. Therefore, with proper maintenance and management, urban gardens may serve as suitable conservation space for common pollinator species.

Lay Summary

Humans are responsible for massive population declines and extinctions in many animal species, including pollinators. This is mostly because of urbanization and agriculture practices, which result in lost habitat space and necessary plants for many pollinators. To correct for this, some are turning to urban native plant gardens to help with conservation efforts. We are testing whether these urban gardens are survivable for pollinator young. We chose 24 gardens around Louisville, KY which vary in how urban their surroundings are. We placed caterpillar models on plants in these gardens, and determined which predators were responsible for resulting damage. Although the amount of damage was similar no matter how urban the gardens are, wasps damaged more models in urban gardens than in suburban gardens, and birds, mammals, and spiders damaged more models in suburban gardens than in urban gardens. It seems that urban gardens which are well taken care of may be used for pollinator conservation.

Included in

Biology Commons