Over the past century, the percentage of the United States population residing within urban areas has soared, and with it the amount of land cover dedicated to residential housing. Residential properties form unique habitats given the high degree to which their plant communities are designed and shaped by homeowners and landscapers. Ecological theory has the potential to influence the management of these spaces, yet its incorporation has historically been lacking in this setting. The associational resistance and dilution effect hypotheses propose that diverse plant communities inhibit the abundance of pests, which should translate into less plant damage. The objective of this research was to determine whether more diverse woody plant communities on residential properties required fewer pest management interventions (PMI) as predicted by these analogous hypotheses. We compiled inventories of the woody plants found on the residential properties of 37 clients of Bartlett Tree Experts (BTE) in the Mid-Atlantic. We then analyzed three years of PMI records for each property performed by BTE field technicians.
Results/Conclusions
A significant negative relationship existed between the plant richness on a property and the number of PMI required during a visit by BTE technicians. This pattern is particularly robust when considering it held for the total suite of phytophagous arthropods and plant pathogens typically encountered in residential landscapes. This study provides support for the hypothesis that increased plant diversity can translate to fewer PMI, and consequently, fewer pesticide applications. Furthermore, it provides evidence of the importance of biodiversity in urban landscapes for the provisioning of ecosystem services.