Historical changes in bird communities at Quitobaquito Springs, Arizona and impacts of climate, spring flow, and shift from Indigenous to federal-agency management

For nearly a century, bird communities at the oasis of Quitobaquito Springs in the Sonoran Desert have attracted desert ecologists. This spring-fed oasis is among the most biologically and culturally significant sites in arid southwestern North America, but has experienced marked changes in management and is threatened by climate change, border, and other development. We assembled data on birds at Quitobaquito across 83 years (1939-2022) and evaluated the patterns and potential drivers of changes in communities. We found evidence of marked community shifts that included apparent loss and replacement of species dependent on riparian and wetland vegetation, mud flats, agricultural fields, and human settlements, to species that use deeper more openwater environments, generalists, and desertscrub. Strong associations between community composition and shift from Indigenous to federal-agency management, temperature, and spring flow suggest important drivers of change, but associations with precipitation and border development were weaker. Such patterns match those for bird communities at broader scales in nearby and other aridlands and indicate impacts of increasing aridification. Our work represents the first analysis of changes in faunal assemblages at Quitobaquito that quantitatively assesses potential drivers of change, and provides insights for management and conservation.