Since the age of Taíno civilization, the vibrant call of the coquí has been a symbol of Puerto Rican culture. But beyond being emblematic, the call carries an important warning about the health of the island’s wild ecosystems. Now, Puerto Rican researchers are using it to monitor local forests and contribute to conservation efforts.
As the loudest amphibian in the world, the call of the Puerto Rican coquí is well-known across the archipelago. However, in recent years, researchers have noticed changes in the way these frogs communicate. One study found that, due to climate change, coquíes are shrinking in size and croaking at higher pitches.
Now, new research on the island is using the science of bioacoustics– the study and monitoring of the production and transmission of animal sounds—to better understand the health of its natural environments. Sounds made by animals, from the calls of coquís to those of birds and crickets, convey valuable information about the state of an ecosystem.
“This system of making stationary recordings allows us to gather rich information that would otherwise have been nearly impossible to obtain,” explained Dr. Gisela Crespo Martínez, a researcher at the University of Puerto Rico (UPR), Río Piedras Campus. She highlighted that the opportunity to listen to the forest in a natural environment—without human presence—makes all the difference in studying its ecosystems.
Crespo Martínez’ research focuses on the melodious coquí, one of 14 species of coquíes remaining in Puerto Rico, down from the 17 that once existed. As part of this initiative, she studies the biological aspects of the frog, such as its size, jumping ability, and song. These data help researchers better understand the challenges the endemic amphibian faces due to the changes occurring in its environment.
“These animals are known as bioindicators, which means they inform us about the condition of our natural ecosystems. They’re excellent for that,” Crespo Martínez explained. The researcher demonstrated this concept using recordings of coquíes singing in the forest. In a recording from the wet, warm season, several species of coquíes can be heard calling throughout the night. In contrast, a recording from the cold, dry season reveals a noticeable drop in their calls.
This is because coquíes, as amphibians, are highly sensitive to changes in humidity and temperature. “An amphibian exposed to extreme dryness, especially these frogs that need moisture for oxygen to pass through their skin, will not do well,” emphasized Crespo Martínez in an interview with El Nuevo Día.
These frogs depend on the existence of balanced microhabitats—specific areas within an ecosystem that provide unique conditions for plants and animals—to regulate their biological functions. As a result, climate change can significantly impact the coquí’s behavior and overall health.
The coquí’s song, in particular, offers valuable insight into how the frog is being affected by changes in its environment. “Singing uses up metabolic energy in a remarkable way,” explained Crespo Martínez. As a result, when coquíes are impacted by environmental changes, their song is often the first thing to be affected.
By monitoring coquíes throughout the seasons, researchers can compare the frogs’ calls to historical data and predict how they are being impacted by environmental changes. Crespo Martínez explained that coquíes play a crucial role in their ecosystems, serving as both predators of pests like mosquitoes and a key food source for larger animals, such as birds and snakes.
A decline in coquí calls can signal a drop in the health of frog populations, which serves as an important indicator of the overall health of the ecosystem. Being such an important species, their well-being reflects the broader state of Puerto Rico’s rainforests. Moreover, as the researcher mentioned, the sound of the Puerto Rican night would feel incredibly lacking without their constant chorus.
Crespo Martínez is currently preparing to publish her study results. With this data, she hopes to help the government and environmental organizations better identify key regions and determine the necessary actions to support conservation efforts across Puerto Rico.
This article was translated from my initial coverage in Spanish. Read the original article here.