Generales

By: Natalia Piedrahita Tamayo- Journalist

In the vocalizations and songs of fauna and the resonances of flora lie keys that allow us to know the identity of species and deeply study phenomena related to the biology and connections of each ecosystem.

Nymphargus rosada. Photo courtesy: Mauricio Rivera Correa. 

Close your eyes and imagine a bird’s song or a stream’s whisper. The information of the individual or entity that emits it travels in that echo that reaches your mind. Beyond the aesthetic assessment or the well-being that sounds provide, they are a tool for science to find out key issues, such as the state of conservation of a forest or the interactions that occur between different species.

Human perception of sounds has been categorized by science according to the origin of the sounds. The sounds of the Earth are classified as geophony. Noises and voices of people or things made by humans are classified as anthropophony, and the songs of the life that surrounds us are considered biophony. These elements are studied in different dimensions by bioacoustics or ecoacoustics, which are methods to understand biodiversity from an auditory point of view.

"As a tool to explore specificities of species, songs can help us to identify differences in their behavior. It is like hearing someone from Pasto, and you can tell from their accent that they’re not from Medellín. In the world of amphibians, sounds help us determine the species and when they are communicating or reacting in a particular context", explained Mauricio Rivera Correa, herpetologist and researcher at the Institute of Biology. Together with the members of the East Campus’ BIO Talent Incubator, they have recorded the songs of frogs to understand their evolutionary attributes.

Antioquia wren —Thryophilus sernai— illustration by Diego Armando Zapata Zapata for the book Aves del Cañón del río Cauca.

The aspects that are analyzed in the sounds of species are: duration and frequency of their voices, what place they sing or vocalize from, whether the song has one, two or three notes, and whether it has rhythms. The soundscapes where the species are involved are also studied.

“We have to understand the whole orchestra", said Juan Manuel Daza Rojas, leader of the Herpetological Group of Antioquia, an A1 category group in the Ministry of Science. “We are using biophony —sounds from organisms— to understand how a forest, a paramo or a disturbed forest sounds, and how these ecosystems are connected. We are not only looking into individual species but also their environment. Our goal is to collect useful information to monitor and conserve species".

The researchers agree that each species may have variations in its vocalizations depending on its environment. Other males singing, cold weather and courtship are factors to consider. However, the level of specialization of the bioacoustics researchers' ears allows them to go beyond these variations by determining when it is a different species.

Different researchers in the exact and natural sciences have developed repositories, databases, research projects and publications about bioacoustics and ecoacoustics. These are some of the projects led by members of Universidad de Antioquia:

The Sound Universe of Birds

Songs of the Antioquia wren -Thryophilus sernai. Ecology and Vertebrate Evolution Research Group, Institute of Biology. 

The uses of bioacoustics in ornithology have resulted in data related to taxonomy, sexual selection and phylogenetic relationships. Professor Héctor Fabio Rivera Gutiérrez has participated in several studies on acoustic diversity in birds, as well as other groups such as whales and fish. He has analyzed song variation and its relationship with genetic variation in widely distributed bird species. Moreover, he has evaluated the role of acoustic communication as a sign of disease, as in the case of the black-striped sparrow —Arremonopsco nirrostris— and avian malaria.

Rivera Gutiérrez also participated in the monitoring of birds around Hidroituango, where the Ecology and Vertebrate Evolution Group collected the songs of more than one hundred species of birds and the "bioacoustic characterization of mating calls of a freshwater fish —Prochilodus magdalenae— for passive acoustic monitoring".

Bottlenose Dolphin Vocalizations

Vocalizations of Tursiops truncatus, recorded at Great Barrier Island, New Zealand. Courtesy: Jessica Patiño Pérez.

The vocalizations of aquatic mammals or cetaceans, specifically of the bottlenose dolphin —Tursiops truncatus— are decisive for orientation and echolocation. Moreover, these vocalizations are used for communicating, establishing social networks and displaying skills. Biologist and researcher Jessica Patiño Pérez has dedicated herself to studying and recording the vocalizations of these dolphins on the coasts of New Zealand, as they are one of the marine species most threatened by tourism on an international scale.

She has also devoted her academic work to the evaluation of the incidence of anthropogenic noise on cetaceans to propose the creation of public policies that protect marine fauna.

Sound Interactions in Amphibians

Songs of the frog Andinobates cassidyhornae. Courtesy: Mauricio Rivera Correa.

Frogs are the group of amphibians that produce the most sounds: They vociferate when they are preyed on, when there are conflicts between males, when they want to demarcate territory, and when it rains. "There are 850 existing amphibians. and 790 anurans in Colombia. Not all of them sing. However, only 120 species have been recorded. That is, we know the acoustics of only 15% of the frogs in the country with the second highest diversity of frogs in the world".

Mauricio Rivera Correa, together with the students of the East Campus’ BIO Talent Incubator, has recorded these frog songs to understand their evolutionary attributes. He participates in several research projects, among which the following stand out: Status, Development and Trends of Studies into Acoustics of Fauna in Colombia, and Biodiversity of Sounds: Documentation of Acoustic Signals of Anurans in Colombia. His objective is to generate an open science repository.

Herpetology Soundscapes

Songs of the frog Nymphargus rosada. Courtesy Mauricio Rivera Correa.

Juan Manuel Daza Rojas' research experience is in Colombian soundscapes: forests, paramos and jungles are his destinations. Although he has researched specific species, his focus is on what he calls "the complete orchestra", that is, the diverse interactions that occur in a specific place. In doing so, he conducts studies into the ecology and conservation status of a habitat and the well-being of the fauna that live in it.

His most recent research is related to the ecoacoustics of tropical rainforests and the biogeography of dry forests in Colombia. "How does a bird species respond to bio- or anthropophony? The soundscape offers us several answers. Sometimes, you cannot see an animal, but the recorder tells us that it is there, and it can even give us details of when the animal sings". This statement from Daza Rojas makes it clear that what the eye does not see can be identified through sound.

The repertoire of songs and vocalizations of the diverse Colombian fauna has been collected and studied by researchers from various academic units of Universidad de Antioquia. Today, bioacoustics is one of the scientific sources where keys to understand the dynamics of ecosystems can be found.