The interplay between urban greenspace, cats and the occurrence of rats and mice in private gardens in the Netherlands

Muridae such as rats and mice are important hosts of (zoonotic) pathogens in urbanized environments. Controlling their population size is an important component of public health policies to reduce human disease risk. Recent studies suggest that rodent populations may increase due to urban greening, but this could also be counteracted by domestic cats and wild predators that inhabit urban greenspaces. Here, we assessed how the presence of brown rats (Rattus norvegicus) and mice (i.e., the house mouse (Mus musculus), wood mouse (Apodemus sylvaticus), and voles (Microtus spp.)) in urban environments relates to neighbourhood greenness and the occurrence of predators. We used camera traps to survey the occurrence of rats, mice, and their predators in 758 private gardens located along gradients of greenness in 25 municipalities across the Netherlands. Detection and occupancy were modelled using logistic mixed models and occupancy models. Mice were detected in 40.6% of the gardens and rats in 9.6%. Detection of rats and mice could not be explained by greenness but was negatively related to the presence of domestic cats. Rat detection was positively associated with the availability of open water and negatively associated with neighborhood wealth. Mice occupancy was positively associated with the presence of mustelids and brown rats, greenness, the availability of open water and human population density. Our results suggest that greenness is a less important driver than the presence of domestic cats for the mere presence of rats and mice in private gardens in urban environments.