Canopy cover instigating feces deposition on paved roads in urban areas

Abstract

Paved roads (PRs), a key feature of urbanization, adversely affect ecosystem processes, including seed dispersal. PRs can influence the ecological functions of urban forests because of their proximity to trees and forest fragments. Therefore, understanding the effects of two critical factors, canopy cover and proximity to a forest patch, on fecal deposition on PRs is essential for assessing the impact on animal-mediated seed dispersal. In this study, we quantified fecal deposition on PRs and analyzed the effects of canopy cover and distance from forest fragments on this deposition. We also estimated the potential seed loss resulting from fecal deposition on the PRs in urban forest fragments of Yokohama, Japan. In total, 1976 fecal samples were collected from the PRs. More of these samples were observed on PRs near forest patches (n = 1671) than on PRs distant from forest patches (n = 305). The canopy cover significantly influenced fecal deposition on PRs. Numerous bird fecal samples on the PRs were expected to contain at least one seed. In addition, approximately 949 seeds could be deposited in the feces of the birds. This study indicates that PRs are critical factors contributing to seed dispersal disservice within urban ecosystems. Urban forest management practices should also consider mitigating the impact of PRs on species interactions and the services they provide.