Green City and connected habitats? Assessing the impact of urbanization on mammal diversity

As urban expansion fragments natural habitats, there is a growing concern to improve green patch connectivity for biodiversity within cities globally. Focusing on Freiburg, Germany, one of the greenest cities in Europe, we investigated how patch connectivity is shaping mammal occurrences and species‐specific consequences in urban areas. We particularly aimed to gain insight into patch connectivity's effect on species richness of medium‐ to large‐sized urban mammals. For this, we analyzed mammal occurrence data collected using motion‐triggered camera traps. We assessed the patch connectivity's effect, as well as urbanization, vegetation, and fragmentation proxies, on the species‐specific occurrence probability and on the total species richness of urban medium‐ to large‐sized mammals by multi‐model inference. We found that higher impervious surface proportion significantly decreases the occurrence probability of the European badger Meles meles , roe deer Capreolus capreolus , red fox Vulpes vulpes , and the overall measured medium‐ to large‐sized urban mammal species richness. Our analysis shows less influence of patch connectivity on species‐specific occurrences and highlights a negative influence of urbanization on total mammal species richness. More empirical studies connecting multi‐city comparisons are necessary to reveal commonalities/variations in understanding how mammals respond to patch connectivity across urban environments globally.