Turn over a few rocks and logs in a moist forest and you will certainly find a salamander. Well, not exactly. While this is true in many areas in North America and Europe, salamanders are quite rare in some other places, where other types of amphibians, such as frogs and caecilians, are common.
Contrary to the general patterns of global biodiversity, where tropical forests harbor the majority of species, the bulk of salamander diversity is found in temperate forests of the northern hemisphere. Most groups of salamanders are confined to temperate zones, including a high number of species that are be found only in the United States.
One group of salamanders has, however, successfully colonized Central and South America: Lungless salamanders (Plethodontidae). These small-size, lizard-like amphibians are usually terrestrial and inhabit a variety of habitats, including the forest floor, crevices and caves, inside bromeliads and tree holes—some are even found high up in tree canopies.
Brazil is the country with the most amphibian species anywhere in the world—13 percent of the 7,800 known amphibian species occur in the country. However, out of more than one thousand amphibians in Brazil, only five are salamanders. In fact, until very recently only a single species was recognized—a study in 2013 discovered three new species and provided scattered records of another one. All Brazilian species are members of the lungless salamanders group, and are restricted to Amazonia. They are all relatively rare, extremely poorly known with respect to their biology, and most already face major threats to their survival.
Pará’s Lungless Salamander (Bolitoglossa paraensis), one of the five species of salamander that occur in Brazil—the species is threatened with extinction due to destruction of its forest habitat. (Photo: Pedro Peloso)
Conservation of Amazonian Salamanders
One of the five species of Brazilian salamanders is Pará’s lungless salamander (Bolitoglossa paraensis), which is restricted to forested areas of the easternmost portion of Amazonia. Although locally abundant where it occurs, the species has a patchy distribution and is only found in a few well-preserved rainforest areas. The species does not tolerate too much disturbance to its habitat and cannot survive in open or cleared areas. Most of the species’ range is within the Amazonian Arc of Deforestation, and therefore the Brazilian Government has listed the species as officially threatened with extinction.
The other four species also appear to be rare and are usually found in areas with increasing threats to their survival. These threats include rampant deforestation, pollution, changes in rain patterns that may affect their reproductive cycle, the building of large hydroelectric dams (Tapajós and Madeira Rivers) and, potentially, infectious diseases (such as chytrid fungus).
Caldwell’s Lungless Salamander (Bolitoglossa caldwellae) was described in 2013—it was named after biologist Janalee Caldwell, whos dedicated many years to the study and conservation of Amazonian amphibians. Very little is known about its biology and distribution.
The Brazilian portion of the Amazonian rainforest harbors an incredible diversity of animals and plants, many of which are unique to that part of the globe, or are very rare.
A large portion of Amazonian species are poorly known in most aspects of their biology and geographic distribution, which makes any assessment of their conservation status difficult. In the specific case of amphibians, several Amazonian species were never assessed by the International Union for Conservation of Nature and Natural Resources (IUCN) Red List of Threatened Species. Moreover, many of those that were evaluated are labeled as Data Deficient (DD)—this means there are no sufficient scientific data for a conclusive assessment of their conservation status.
Out of the five species of salamanders in Brazil, one is listed as DD and three have not yet been evaluated. Finally, given that many areas of the Brazilian Amazonia are completely unexplored, it is possible that additional species of salamanders will discovered there in the future.
The bottom line is: we need more field biologists collecting data on Amazonian salamanders (and other organisms). This is critical for their survival.
Tapajós Lungless Salamander (Bolitoglossa tapajonica), one of three species discovered in a study in 2013. The construction of hydroelectric dams and deforestation in the Tapajós River region threatens the habitat of this species—and consequently imperils its survival. (Photo: Pedro Peloso)