The impact of livestock on Argentina's globally threatened grassland birds

ADRIAN S. DI GIACOMO; ALEJANDRO G. DI GIACOMO; MELANIE BROWNE; FLORENCIA PUCHETA

Congreso; II Ornithological Congress of the Americas; 2023

Threats to grassland birds are mainly related to land use change for crops and afforestation. However, the use ofgrasslands for cattle ranching could affect some species that have very specific breeding habitat requirements, suchas threatened species. To evaluate the impact of current cattle ranching on threatened grassland bird populationsin northeastern Argentina, we compared the results obtained in reproductive studies conducted in cattle ranchesand protected areas for: Strange-tailed Tyrant Alectrurus risora, Vulnerable IUCN); Saffron-cowled BlackbirdXanthopsar flavus, Endangered IUCN; and Capuchino Seedeaters Sporophila spp., Vulnerable-Endangered IUCN.We found that the nesting sites of these species are very restricted spatially in grasslands with livestock use. Inaddition, density of nests and reproductive success in cattle grasslands were consistently lower than in protectedareas. Factors contributing to the negative impact of cattle ranching on threatened grassland birds in NE Argentinaare related to increased burning, use of feeders, use of agrochemicals, changes in nest predator communities, andincreased brood parasitism. To conserve populations of threatened grassland birds in cattle ranches, the creationof small refuges under livestock exclusion that guarantee bird reproduction is recommended, along with themanagement of the surrounding grasslands with low livestock rates, elimination of feeders and agrochemicals, andlow frequency of fires.