Due to their isolation from the mainland, amphibians were unable to reach the Galápagos Islands for thousands of years. However, a small but extremely adaptable species of frog has now spread across the islands – with far-reaching consequences for the native wildlife. The tree frog Scinax quinquefasciatus, originally from Ecuador, was probably introduced as a stowaway in the late 1990s and has since spread widely on Isabela and Santa Cruz.
What is particularly worrying is that the frogs are not only spreading in settlements and agricultural areas, but also in the protected areas of the Galápagos National Park (GNP). They reveal their presence themselves – through the loud calls of the males during the mating season from January to May. During this period, the frogs gather near bodies of water where the females lay their eggs. Hundreds of tadpoles hatch and live in the water until they reach their adult form.
THOUSANDS OF FROGS APPEAR IN A SHORT PERIOD OF TIME
Recent studies using counts and acoustic recordings show that thousands, sometimes even tens of thousands, of frogs gather at some bodies of water. Loud frog choruses could even be heard in remote locations within the GNP.
Farmers on Santa Cruz and Isabela report that the frogs only appeared a few years ago. This is probably because the water reservoirs, which are essential for agriculture, provide perfect breeding grounds for them.
WHY DO THE FROGS POSE A THREAT?
For the people living near these reservoirs, the loud calls of the frogs certainly mean severe restrictions on their sleep at night. The frogs also threaten the islands' native wildlife.
They eat insects – the very same insects that many native birds, such as the famous Darwin's finches and other songbirds, feed on. Thousands of frogs consume vast quantities of insects every day, creating direct competition for food.
This development is alarming. To effectively combat the spread of the frogs, their behavior, distribution patterns, and interactions with other animal species, including giant tortoises, are currently being studied. It is important to find out how the frogs survive during the dry season.
TARGETED CONTAINMENT IS NECESSARY
The goal is to develop targeted, ecologically compatible measures to contain this invasive species and thus protect the delicate ecological balance of the islands.
Your support helps us to make these silent threats from loud intruders visible and to preserve the unique nature of the Galápagos Islands.