🔗 Share this article The Galápagos Islands Lacked Any Indigenous Amphibians. Until Countless Numbers of Amphibians Arrived During her regular commute to the research facility, scientist the researcher crouches near a shallow pond covered by thick vegetation and collects a small green audio recorder. She had placed there overnight to capture the distinctive calls of the Scinax quinquefasciatus, recognized by local researchers as an non-native threat with consequences that scientists are starting to comprehend. Although teeming with unique animals – such as ancient large turtles, marine lizards, and the famous finches that sparked Darwin's evolutionary theory – the island chain near the shoreline of South America had long remained free of amphibians. In the late 1990s, this changed. Several tiny tree frogs made their way from continental the mainland to the islands, probably as stowaways on cargo ships. The invasive species came in the 90s and have become established on Isabela and Santa Cruz islands. Genetic research suggest that, through time, there have been multiple unintentional arrivals to the archipelago, and the amphibians now have a strong foothold on several islands: Isabela and Santa Cruz. The numbers is expanding so rapidly that scientists have been finding it difficult to monitor, estimating populations in the hundreds of thousands on every island, across developed and agricultural areas, but also in the protected natural reserve. When the biologist tagged frogs and attempted to find them in the following 10 days, she could locate only a single marked frog from time to time, suggesting their numbers were massive. They calculated 6,000 frogs in a single pond. "The calculations are still very conservative," states the researcher. "I'm quite certain there are additional numbers." Acoustic Chaos and Growing Concerns The frogs' proliferation is clear from the acoustic chaos they create. "The number of frogs and the noise – it's truly insane," says San José. For the scientists, their nocturnal mating calls are helpful in estimating their existence in remote areas, using audio devices like the one near the office. But local farmers say the calls are so loud they prevent sleep at night. "In the wet season, I regularly hear their croaks and they're really loud," says a local coffee farmer from the island. "Initially it was a shock, seeing the first frogs in the region," says Larrea Saltos, who started observing their large numbers about three years ago when one jumped on her palm as she was walking out of her house. Ecological Impact Stays Unknown The noise isn't the fundamental problem, however. While the amphibians has been in the islands for almost 30 years, experts still know limited information about its impact on the archipelago's precariously balanced terrestrial and aquatic ecosystems. Researchers are finding out more about the amphibians, including that they can remain as larvae for as long as half a year. On archipelagos, it is very common for non-native organisms to thrive, as they have none of their enemies. The islands counts 1,645 introduced species, many of which are seriously disrupting the safety of its endemic ones. A recent research suggests the invasive frogs are hungry bug eaters, and might be unevenly eating uncommon bugs found only on the archipelago, or depleting the nutrition of the region's rare birds, affecting the food chain. Unique Characteristics and Management Difficulties The island frogs have exhibited some atypical traits, including surviving in brackish water, which is uncommon for frogs. Their development process is also highly inconsistent, with some larvae turning into frogs very quickly and others taking a long time: the researcher witnessed one which remained as a tadpole in her laboratory for half a year. "We truly don't know this part," she says, concerned the tadpoles could be impacting the islands' clean water, a very limited commodity in the islands. More research is required to establish the optimal way to manage the frogs without harming other organisms. Techniques to curb the amphibians in the beginning of the century were mostly ineffective. Conservation officers tried collecting large numbers by manual methods and gradually raising the salinity of lagoons in without success. Studies indicates applying caffeine – which is extremely poisonous to amphibians – or using electrical methods could help, but these approaches aren't necessarily secure for other uncommon Galápagos organisms. Lacking answers to more of the fundamental issues about their biology and effect, culling the frogs might not even be the correct way to advance, says San José. Funding Challenges for Study While she expects the increasing use of environmental DNA methods and DNA examination will help her team understand of the invader, funding for the research has been hard to obtain. "Everyone wants to give support for preserving frogs," says San José. "But it's more difficult to find funding for an invasive frog that you might want to manage."