Seven new species of tiny frogs have been discovered in the Brazilian Atlantic Rainforest, a cloud forest in the southeastern part of the country. This is exciting news for ecologists, as amphibians are very sensitive to habitat changes, and can serve as indicators of overall ecosystem health.

Each species displayed strong microendemism, meaning that they were only found in a small area of the montane cloud forests, isolated by valleys of unsuitable habitats. None of the newly discovered frogs exceeded 14 millimetres in length, though all had some unique characteristics, including fewer fingers and toes than most larger frogs, as well as vibrant skin colouring, which was sometimes found to be poisonous.

Over the years, scientists have seen a severe decline in amphibian populations, with many species already having gone extinct. This is primarily due to habitat loss and chytridiomycosis, a disease caused by the chytrid fungus. “In 1999, a new species of chytrid was described that infects the skin of amphibians and was named Batrachochytrium dendrobatidis or “Bd” for short (Longcore et al, 1999).”

Over two hundred species of amphibians have been driven to decline or extinction due to the disease caused by the Bd fungus. Still, amphibians are threatened much more imminently by habitat loss and climate change, because they can only survive within a narrow range of temperatures and climates. Discovering new species gives ecologists hope that there are still pristine habitats available to sustain a variety of amphibian species.

Another considerable threat to amphibian populations is the use of the pesticide atrazine, which has shown in a number of peer-reviewed studies to change the gonadal development of frogs, causing widespread hermaphroditism and even turning males into females. Atrazine, a known endocrine disruptor, is a widely used pesticide in the US, though it has been banned in Europe. A study conducted by UC Berkeley in 2010 concluded that atrazine “wreaks havoc with the sex lives of adult male frogs, emasculating three-quarters of them and turning one in 10 into females.”

During the 2000s, the US Environmental Protection Agency conducted studies on atrazine and concluded that it does not adversely affect amphibian gonadal development and, therefore, has not required additional testing on the chemical, though their conclusion has been contested.

Amphibians are indicators of ecosystem health because of their place in the food chain. According to Ashley Mattoon of the Worldwatch Institute, “In some temperate and tropical forests, amphibians account for more biomass than any other vertebrate group: if you could weigh all the frogs and toads in a forest, there’s a good chance you would find more mass in them than in the forest’s reptiles, birds, or mammals. That’s important because it means that a great deal of the nutrients and energy in these places normally passes through or resides in amphibians. In ways large and small, amphibians shape the ecosystems of which they form a part.”

By identifying more frog species and studying the conditions necessary of healthy habitats, scientists can design targeted conservation efforts to protect these sensitive creatures, which are such an integral part of the food chain. Even though the miniature frogs discovered were found in “protected” areas, such remote places in Brazil still grapple with illegal deforestation of pine tree plantations, and cattle ranching. The study that exposed the discovery, published in PeerJ, suggested that the new species, “should be integrated into the Plano de Ação Nacional para a Conservação dos Anfíbios e Répteis Ameaçados da Região Sul do Brasil, an initiative organised by the Instituto Chico Mendes/Ministry of the Environment that seeks to organise conservation initiatives for the conservation of the herpetofauna of southern Brazil.”

Government oversight and enforcement of conservation efforts can make all the difference for habitat health and sustainability for threatened species, especially since the public is not always properly informed about how ecosystem diversity is a basic precursor for sustainability.

The discovery of these seven new species gives conservationists hope for the future of amphibian species; they expect to find and catalogue even more in the near future. We can only hope that conservation efforts will keep up with the pace of discovery.
Sarah Sakeena Marshall, B.S. Environmental Policy