In an increasingly anthropogenic world, urban green areas are critical for human well-being because of the ecosystem services they offer. However, the management of these areas often prioritizes economic, architectural, and aesthetic needs over ecological functionality, undermining the benefits they ought to provide. Actions to restore the functional ecological processes of urban green areas have thus become increasingly urgent. This study investigated the impact of urban green area characteristics on the community composition of an indicator animal group to inform Nature-Based Solutions (NBSs) for urban biodiversity and sustainability enhancement. We analyzed data on small mammal community composition from three Italian metropolitan cities (Milan, Florence, and Rome), focusing on the distribution pattern of synanthropic and non-synanthropic species. Small mammal surveys were carried out using hair tubes in sampled areas located along a gradient of green area size and fragmentation. Multiple Linear Mixed Models assessed the influence of spatial and habitat green area characteristics on species richness. Synanthropic species richness was positively associated with manicured urban parks, while non-synanthropic species richness was higher in woodland green areas characterized by high shrub cover. Through a Linear Mixed Model and NODF-based Nestedness analyses, we found that competitive exclusion and selective extinction/colonization processes did not significantly influence community composition. These insights emphasize the major influence of habitat composition in supporting functional communities of urban small mammals. To move toward resilient urban ecosystems, NBSs must primarily be implemented at a local scale by creating green patches with high habitat quality, and secondarily, they should be embedded in an interconnected and functional network at a city scale.

Noise is one of the greatest environmental health risks causing health issues via stress, deteriorated sleep, and annoyance. Noise annoyance is partially explained by measurable sound characteristics, and partially by other environmental, situational, and individual factors. Greenery might decrease noise annoyance via hiding the noise source, facilitating psycho-physiological restoration, and masking noise. However, whether greenery near home and some individual traits moderate the effect of road traffic noise on noise annoyance has been rarely assessed in everyday life. Using cross-sectional Environmental Health survey (n = 7321) collected at the Finnish capital region in 2015–16, we analysed the interactions between road traffic noise, green space, tree cover density, green view from home, noise sensitivity and nature relatedness on noise annoyance, using logistic regression modeling. Covariates included age, gender, socio-economic indicators, living floor, and the direction of windows. More green space and greater tree coverage around home were associated with lower odds of road traffic noise annoyance when road traffic noise was < 60 dB Lden but increasingly higher odds at higher noise levels. No other interactions were found. Green view was only tentatively associated with lower odds of noise annoyance. Noise sensitivity and nature relatedness were related to greater odds of noise annoyance. In conclusion, greenery might mitigate noise annoyance at low-to-moderate road traffic noise levels. At higher noise levels, greenery may even increase noise annoyance. This could be due to incongruency between expected and actualised soundscapes in greener areas. However, more studies, especially interventions, are needed to confirm this.