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An international team including researchers from the University of Granada (UGR) and the National Museum of Natural Sciences (MNCN-CSIC) has studied the distribution of 115 species of birds in spring and 72 that spend the winter in nine European cities.
They concluded that the configuration of urban areas can favour the presence of species with varying characteristics, with implications for the improvement of ecosystems and public health. The article, published in the journal Science of the Total Environment, proposes actions to promote the creation of cities that are not only more habitable for birds, but also more liveable for citizens.
For this study, which also involved scientists from research centres in Finland, Poland, Germany, the Netherlands and the Czech Republic, the research team collected data on bird communities in the two main types of urban development (land-sparing and land-sharing) in several European cities, including Madrid, Granada, Toledo and Prague.
Land-sharing urban development is characterised by maintaining small green areas, usually in the form of private gardens and street vegetation, interspersed with single-family buildings, and low population density. In contrast, land-sparing urban development is characterised by large green areas (usually large parks and gardens) that are clearly separated from the built-up areas, which are densely populated and contain apartment blocks.
“For each species identified in the European cities that were studied, we have quantified characteristics such as their degree of feeding specialisation, the type of nests they build, the effort they invest in breeding, and their longevity. This has allowed us to assess whether urban design favours species with certain types of traits,” explains MNCN researcher Mario Díaz.
“In previous studies, we had already found that the presence of different bird communities was determined by land-sharing and land-sparing types of urban development,” says UGR researcher Juan Diego Ibáñez Álamo. “This research has also allowed us to identify the characteristics that allow them to settle in one type of urban area or another,” he adds.
Land-sparing urban areas are breeding grounds for birds that lay many eggs, use open nests more frequently, and have short life cycles, such as stonechats, chiffchaffs and crested larks. In contrast, land-sharing urban areas are dominated by birds with more demanding breeding requirements and longer life cycles, such as great tits, kestrels and gulls.
“The data we have obtained clearly shows the need to promote a mix of both types of urban development to allow for greater bird diversity. Greater urban biodiversity is not only beneficial for our immediate environment but also for our own health and wellbeing,” the MNCN researcher concludes.