🔗 Share this article Galápagos Lacked Any Native Amphibians. Then Countless Numbers of Amphibians Arrived On her daily walk to the scientific station, biologist the researcher crouches near a shallow water body covered by thick vegetation and collects a compact green sound device. She had placed there through the night to record the characteristic croaks of the Fowler's snouted treefrog, known by Galápagos researchers as an non-native species with effects that experts are starting to understand. Despite abounding with remarkable wildlife – including ancient large turtles, swimming iguanas, and the famous birds that sparked Darwin's theory of evolution – the Galápagos archipelago off the shoreline of Ecuador had historically been devoid of frogs and toads. During the 1990s, this changed. Some tiny tree frogs made their way from continental Ecuador to the islands, probably as stowaways on transport vessels. The invasive species arrived in the 1990s and have become established on multiple Galápagos islands. DNA research suggest that, over the years, there have been repeated unintentional arrivals to the archipelago, and the frogs now have a strong presence on several locations: multiple locations. The population is growing so rapidly that researchers have been finding it difficult to keep track, estimating populations in the millions on each island, across developed and farming areas, but also in the conservation natural reserve. When San José marked frogs and attempted to find them in the subsequent week and a half, she could locate only a single marked frog occasionally, suggesting their populations were enormous. They estimated six thousand frogs in a single pond. "Our estimates are still very conservative," states San José. "I am pretty sure there are additional numbers." Acoustic Chaos and Growing Concerns The frogs' abundance is evident from the acoustic disruption they create. "The amount of frogs and the sound – it's really incredible," says San José. For the researchers, their nightly vocalizations are useful in estimating their existence in remote areas, using audio devices like the one near the office. But local agricultural workers say the calls are so raucous they keep them up at night. "In the wet season, I constantly hear their calls and they're really loud," says a local coffee farmer from the island. "Initially it was a shock, observing the first frogs in the area," says Larrea Saltos, who started observing their abundance about three years ago when one jumped on her palm as she was stepping out of her front door. Ecological Impact Stays Unknown The noise isn't the primary problem, though. While the amphibians has been in the Galápagos for nearly 30 years, scientists still know very little about its effect on the archipelago's precariously balanced terrestrial and aquatic environments. Researchers are discovering more about the amphibians, including that they can remain as tadpoles for as long as half a year. On archipelagos, it is very common for non-native organisms to prosper, as they have few of their enemies. The islands has 1,645 invasive types, many of which are seriously affecting the survival of its endemic ones. A recent research indicates the invasive frogs are hungry bug consumers, and might be unevenly consuming rare bugs found only on the archipelago, or reducing the nutrition of the region's uncommon birds, affecting the food chain. Unusual Traits and Management Difficulties The Galápagos amphibians have shown some atypical characteristics, including living in slightly salty water, which is rare for frogs. Their development process is also extremely inconsistent, with some larvae turning into frogs very rapidly and others taking a extended period: the researcher observed one which stayed as a larva in her laboratory for half a year. "We really don't know this part," she says, worried the larvae could be impacting the region's freshwater, a very scarce resource in the islands. Additional studies is required to establish the optimal way to control the amphibians without affecting other organisms. Methods to curb the frogs in the early 2000s were mostly unsuccessful. Park rangers tried collecting significant quantities by hand and slowly raising the salt content of ponds in vain. Research indicates spraying coffee – which is extremely toxic to amphibians – or using electrocution could help, but these approaches aren't always safe for other uncommon Galápagos species. Lacking solutions to more of the fundamental questions about their biology and impact, removing the amphibians might not even be the right way to advance, says the biologist. Financial Obstacles for Research While she hopes the increasing use of environmental DNA methods and DNA analysis will help her group make sense of the invader, funding for the project has been difficult to obtain. "Everyone wants to give funding for protecting frogs," says the researcher. "But it's harder to find financial backing for an invasive frog that you might want to manage."