What land use better preserves taxonomic and functional diversity of birds in a grassland biome?

The Pampean grassland in South America has been almost completely transformed by human activities and is one of the biomes at the highest conservation risk. Although several land uses are developed in temperate grasslands, studies comparing their impact on bird taxonomic and functional diversity are still missing. We determined what habitat type resulting from human land uses better preserves the assemblage of birds and their functional traits that occur in protected grasslands. We compared taxonomic and functional diversity between protected grasslands and cattle pastures, crop fields, tree plantations, and urban settlements. We surveyed birds and environmental variables in the 5 habitat types using point counts and selected 11 traits to estimate functional diversity. We performed principal component analysis to explore environmental differences between habitat types, ANOVA to compare taxonomic and functional diversity, nonmetric multidimensional scaling to explore relationships between habitat type characteristics and species traits, and similarity percentage analysis to find the bird functional traits that contributed the most to differentiate habitat types. Bird composition and functional diversity in cattle pastures was the most similar to that of protected areas but showed no significant differences with crop fields. In cattle pastures, crop fields, and protected areas, the most frequent species traits were related to narrow ranges and high vulnerability to extinction, whereas urban settlements included traits covering wide ranges or related to impervious areas. When compared with protected areas, land conversion into cattle pastures and some types of agricultural lands resulted in a lower loss of bird species and functional diversity than conversion into tree plantations or urbanized areas. Approximately 35% of species found in protected areas were not recorded in any of the other habitat types. Therefore, we emphasize the need to protect the native habitat. Our findings help with land use planning in the Pampas and other temperate grasslands