Nocturnal noise and habitat homogeneity limit species richness of owls in an urban environment

anglais. Habitat loss and fragmentation are listed among the most significant effects of urbanization, which is regarded as an importantthreat to wildlife. Owls are the top predators in most terrestrial habitats, and their presence is a reliable indicator of ecosystemquality and complexity. However, influence of urbanization on owl communities, anthropogenic noise in particular, has not beeninvestigated so far. The aim of this study was to identify the role of noise and landcover heterogeneity in the species richness ofowl assemblage in the urban ecosystem. Owls were surveyed in the city of Kraków (southern Poland) on 65 randomly selectedsample plots (1 km2). The area of main landcover types, landcover diversity index, mean size of landcover patch, and nocturnalnoise level were defined within the sample plots and correlated with owl species richness. Five owl species were recorded in thestudy area with forests as the dominant landcover type for Tawny and Ural owls, grasslands for Long-eared and Barn owls, andgardens for Little owls. In total, 52% of sample plots were occupied by at least one species (1–3 species per plot). The number ofowl species was positively correlated with landcover diversity index and negatively correlated with nocturnal noise emission.This study demonstrates that species richness of owls in urban areas may be shaped by landcover heterogeneity and limited bynoise intensity. This indicates that noise changes top predator assemblage, which in consequence may disturb predator-preyinteractions within human-transformed habitats.

anglais. Urban ecology, Acoustic predators, Traffic noise, Habitat diversity, Habitat homogenization, Strigiformes

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