WHAT MATTERS MOST? RELATIVE EFFECT OF URBAN HABITAT TRAITS AND HAZARDS ON URBAN PARK BIRDS

Through habitat trait changes, urbanization can represent a threat to biodiversity. However, such effects depend on the capacity of wildlife to tolerate urban-related hazards and use urban resources. In this study, we measured the relative magnitude of the effect that human activity, the presence/abundance of potential bird predators, urban infrastructure, vegetation characteristics, and the presence/abundance of House Sparrows have on native urban park bird species. Our results show that the most important variables explaining the abundance of the studied bird species were vegetation ones, followed by both urban infrastructure variables and the number of potential bird predators. The results of this study show that the relative magnitude of the studied set of variables is species-dependent. Thus, proposing generalized park management and planning activities based on this study could be misleading. However, based on our results, we suggest three management and planning activities that could enhance native bird species numbers within urban parks: (1) increasing the abundance of old trees in urban parks; (2) avoiding urban infrastructure components within parks; and (3) carefully choosing shrub species that could attract large number of birds. Although the presence/abundance of House Sparrows and the number of passing pedestrians were not the principal variable explaining the abundance of any of the studied species; our results suggest that lowering the abundance of House Sparrows and passing pedestrians could enhance the abundance of native bird species in urban parks. Accepted 23 September 2010.