Urban sprawl or compact cities? Importance of landscape matrix morphology configuration to urban bird conservation

There is a growing interest to understand the effects that urbanization has on bird species as well as to identifying opportunities for their conservation in cities. A significant part of the research has focused on testing the importance of size and vegetation of urban green areas has over the maintaining of richness and abundance of bird species. Conversely there is a limited knowledge about the influence that have the matrix design that surrounds this spaces. Mainly in relation to patterns of building height and density. Aspects strongly related to the debate if the cities should be sprawl or compact as they grow and their impact on biodiversity. This study evaluated the link that the morphological landscape configuration of the urban matrix (MLCUM) has directly with the diversity and distribution of birds occupying urban green areas. We characterized and compared bird assemblages in 60 small green areas and 20 larger urban and natural green areas located in Santiago de Chile. These areas corresponded to a stratified sample of contrasting MLCUM based on height and density of the surrounding buildings. 12 bird repeated counts were developed between November 2013 and June 2015. Richness and species-specific abundance patterns were obtained and GLM models were used to quantify and contrast the effect size of multiple variables at different spatial scales. We concluded that the height and density of the urban matrix are modulating the composition and structure of urban bird communities and influence the probability of some species to occupy urban green areas.