Here, we explored this effect by including an environmental noise dimension to test some AAH predictions in two clades of widespread amphibians (Bufonidae and Ranidae) that actively use acoustic signals for communication. These studies, based on the AAH, predict that acoustic signals should experience less attenuation and degradation where habitats are less acoustically complex. To date, most AAH studies have focused on the effect of stratified vegetation on signal propagation. The acoustic adaptation hypothesis (AAH) states that signals should evolve towards an optimal transmission of the intended information from senders to intended receivers given the environmental constraints of the medium that they traverse. We also show that a fine-scale characterization of calling sites allows a better perception of the impact of environmental constraints on call evolution. We find that in spite of existing morphological constraints, vocalizations of torrent dwelling species are most probably constrained by the acoustic specificities of torrent habitats and particularly their high level of ambient noise. We test models of evolution for six call traits for 79 species with regard to the reconstructed history of calling site preferences and estimate their ancestral states. We reconstruct the evolution of calling site preferences, both broadly categorized and at a finer scale, onto a phylogenetic tree for 148 species with five markers (∼ 3600 bp). Here we assess the potential impact of environmental constraints on the evolution of advertisement call in four groups of torrent dwelling frogs in the family Ranidae.

Yet, few empirical studies have verified this prediction, possibly due to a shortcoming in habitat characterization, which is often too broad. Strong environmental constraints should drive call evolution, favoring signals with greater transmission distance and content integrity in a given calling habitat. While acoustic signals are important for communication in many taxa, signal propagation is affected by environmental properties.

Sandra sets torrent