Avian species richness in cities: A review of the Spanish-language literature from the Southern Cone of South America.

South America sustains an important part of the world's terrestrial biodiversity and its population is highly urbanized. Global syntheses have revealed a paucity of urban ecological research in the region; however, local research might be overlooked due to language barriers. As a contribution to disseminating local knowledge, we conducted a synthesis of Spanish-language literature on bird species richness in the Southern Cone of South America - an area of high diversity, endemism, and more than half of the world's terrestrial biome types. In this systematic review, we identified patterns and trends in the literature, and the variables that influence bird species richness. Research has focused on national capital cities and green areas (large urban parks). Most studies covered short periods of time (1 year or less) and involved one season only (reproductive). The most studied biomes were temperate grasslands, savannas and shrublands, and Mediterranean and temperate forests, and no studies were found in mountains or deserts. Bird species richness in cities from the Southern Cone was positively influenced by vegetation cover and plant and habitat diversity; whereas variables associated with urban cover and disturbance exhibited negative effects. Important gaps in knowledge include: research in small and medium size cities, in overlooked biomes (deserts, xeric shrublands, and montane grasslands and shrublands), long-term research comprising different seasons, the inclusion of green spaces other than urban parks, and interdisciplinary studies that consider environmental, social, and economic components of urban ecosystems. By filling these key knowledge gaps, researchers from South America can contribute to the development of science-based actions to preserve nature in an urbanizing world. [ABSTRACT FROM AUTHOR]