The effects of urbanization on species interactions

Cities are renowned for catalyzing human interactions, but their distinctive environments also affect the interactions of other species. We discuss how urbanization affects species interactions and identify key knowledge gaps. With this context and using an eco-evolutionary lens, we frame urban environments as providing three consecutive filters: the presence of species, their co-occurrence and their relationships. Our framework offers a structured model for studying and managing urban species and environments to facilitate conservation and ecosystem services, benefiting urbanites of all stripes. Cities are renowned for catalyzing human interactions, but their effects on urban species are less clear. This Perspective argues for such a focus, and proposes a framework for studying interactions between urban species.