Bird metacommunities of urban parks in the pampean region, Argentina

Metacommunities are the set of local communities that are linked by the dispersion of potentially interacting species. The study of metacommunities is important to elucidate the relationship between processes that occur at different spatial scales. However, bird metacommunities in urban parks have been little studied. The objectives of this study were: 1) to analyze the relative role of species dispersal, environmental selection, and stochastic processes shaping urban bird metacommunities; and 2) to analyze the structure of the metacommunities of birds in urban parks. Bird surveys were made in 51 parks of six cities in Buenos Aires province, Argentina. To obtain the metacommunity structure, three elements were analyzed: coherence, turnover, and boundary clumping. We found that the metacommunity conforms to a clementsian structure, in which groups of species respond in a similar way to environmental gradients. The environmental and connectivity variables explained a greater proportion of the variance than the spatial variable. The composition of species was related to the location of the cities, the distance to the rural area, the distance to the urban center, the number of cars passing near parks, and habitat diversity. Due to the clementsian structure of metacommunities, they probably were structured under a species sorting and mass effect process. The number of cars and habitat diversity in the parks would be acting as environmental filters for bird species, while the distance to rural areas and the distance to the urban center would affect species dispersal to the parks. These findings emphasize the importance of maintaining and improving park connectivity and habitat diversity for bird species, managing them as cities grow.