Effects of American bullfrogs (Lithobates catesbeianus) acoustic invasions in native anuran communities

Biological invasions by non-native species contribute to the loss of biodiversity, changes in its dynamics, and damage to ecosystem services, among others. The American bullfrog (Lithobates catesbeianus) is native to eastern North America and has been introduced in over 40 countries, including Brazil, for human consumption.It is one of the 100 worst invasive species in the world. It is widespread in the Atlantic Forest, and its distribution continues to increase in Brazil. Studies suggest L. cateseanus is related to the decline of native amphibian populations because it competes for resource use, inducing changes in microhabitat uses; is a vector of the Batrachochytrium dendrobatidis fungus; and induces changes in acoustic communication, mainly because of the wide frequency range of advertisement call. To date, experiments analyzing the effects of bullfrog vocalizations on native species have focused on the immediate response of individuals of particular species. Here, we tested the effects of a simulated bullfrog acoustic invasion through automated experiments playing playbacks in natural communities to analyze the medium-term acoustics response in native anuran communities. We used two simultaneous treatments with equivalent richness and composition to test the bullfrog influence on the richness and composition of native species and on acoustic parameters of specific species. Our results showed that the bullfrog invasion simulation experiment did not change species richness or community composition, but it caused a decrease in the presence of four species (Chiasmocleis albopunctata, Elachistocleis cesarii, Leptodactylus mystacinus, and Physalaemus cuvieri) and altered the acoustic parameters of two more species (increased dominant frequency in Dendropsophus jimi and Leptodactylus labyrtinthicus/luctator and decreased call duration and number of calls per minute in L. labyrtinthicus/luctator). An actual invasion of bullfrogs in the studied localities has the potential to change the composition of native communities and acoustic parameters, directly impacting some anuran species. (AU)