Changes in grassland bird communities and breeding success after a fire in the Argentinian Pampas

Abstract

Fire is responsible for the structure and composition of the biological communities in grasslands, despite this, few studies evaluate the effects of fire on bird communities, especially in the southern cone of South America.We compared the structure and composition of vegetation, bird communities, density of nests and predation rates between burnt and unburnt areas in grassland habitats in the Argentine Pampas during two reproductiveseasons following a fire. The abundance, richness and diversity of birds were lower in the burnt areas and followed a pattern of interannual recovery associated with the increase in vegetation cover. The density ofnests and the number of nesting species was higher in the controls only during the first season. The risk of predation of artificial nests in burnt areas was greater one year after the fire in respect to the controls, thisdifference decreased over time in inverse relationship with the percentage of plant cover sorrounding the nests. Our results highlight the importance of a good vegetation structure and cover to support abundant andspecies-rich bird communities, as well as high values of nest density and reproductive success, and the ability of vegetation and bird communities to recover after the fire. However, this successional and temporary loss ofhabitats of high nesting value should be analyzed on a larger scale in order to consider the effect of the total reduction, and the fragmentation of the grasslands in a good state of conservation, on the population dynamicsof grassland birds.