Urbanization affects oak–pathogen interactions across spatial scales

The world is rapidly urbanizing, thereby transforming natural landscapes and changing the abundance distribution of organisms. However, insights into effects urbanization on species interactions, plant–pathogen interactions in particular, are lacking. We investigated powdery mildew infection Quercus robur at continental within-city scales. At scale, we compared levels between urban rural areas different-sized cities Europe, whether plant traits, climatic variables CO2 emissions mediated effect levels. Within one large city (Stockholm, Sweden), further explored local habitat features spatial connectivity influenced during multiple years. severity was consistently higher trees than areas, with some indication that temperature this effect. Stockholm city, had no effect, while accumulation leaf litter negatively affected incidence out three years, more connected lower This study first to describe both within among cities, uncover potential mechanisms behind observed patterns each scale.