Impacto do ruído antrópico na diversidade de aves

Abstract

The constant human expansion creates unprecedented acoustic conditions that can impair acoustic communication by overlapping signals. This process, called acoustic masking, is especially harmful to birds that rely on acoustic communication to interact socially, such as parental care, warning and awareness of predators, territory defense, and mate attraction. In this way, noise can interfere with the reproductive success and survival of the species. While anthropogenic noise becomes ubiquitous, it may be changing the species composition of natural communities, filtering out those species that use the same frequencies. We examined whether species most likely affected by noise have similar frequency use in the acoustic spectrum, body mass and territory size. We evaluated whether mining noise influences the species composition according to the spectral features of their songs and if noise influences the taxonomic and phylogenetic diversity of birds in the Carajás National Forest, Pará. Bird diversity and noise were monitored in five areas, from 2015 to 2019, three under the influence of mining noise and two without noise. In each area, samplings were performed in five monitoring transects, which in turn, had five noise monitoring points each. Our results indicate that the potentially most affected species are large, use lower frequencies (occupied by noise), and require long-distance communication, either for reasons of territorial size or spatial flock dynamics. The areas permeated by noise are composed of species that mostly use high-frequency songs, which may indicate that noise acts as an environmental filter, selecting the species according to the spectral features of their songs. The noise negatively affected the taxonomic and phylogenetic diversities but positive on average phylogenetic diversity per species. Vegetation also influenced diversity, especially species richness. The results show that mining noise can be a selective force shaping bird diversity. Noise is an invisible source of habitat degradation that can affect community assembling and ecosystem functioning.