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In Brazil’s Sooretama, a piece of the Amazon thrives in the Atlantic Forest

  • Sooretama Biological Reserve, one of the last remaining refuges of the Atlantic Rainforest in Brazil, is also a unique site where vestiges of Amazonian species can be found.
  • Even though the biomes lie 1,500 kilometers (930 miles) apart, there’s plenty of evidence to show that the Atlantic and Amazon rainforests were once connected.
  • Common Amazonian species that can be found in Sooretama include the birds like the collared trogon and ringed woodpecker, and the spot-legged wood turtle.
  • But the reserve is under threat from the planned widening of the BR-101 highway, which cuts through the reserve and its surroundings and is already responsible for the deaths of 20,000 animals a year as roadkill.
A common species in the Amazon, the ringed woodpecker (Celeus torquatus) only shows its colors inside Sooretama Biological Reserve and nearby private reserves in the Atlantic Rainforest. Image by Leonardo Merçon.

The forests of the Mata do Tabuleiro region in the Brazilian state of Espírito Santo were once listed among Earth’s most biodiverse regions. But much of this richness has been lost due to human occupation, river pollution, and unchecked deforestation. What were once stretches of exuberant vegetation reaching as far as the eye could see have now been reduced to a few fragments, home to Sooretama Biological Reserve.

The name “Sooretama” comes from the Tupi language and means “the house of the forest animals.” The reserve and the forest complex of which it’s a part are some of the most important remnants of the Atlantic Rainforest in Espírito Santo, and the state’s last stronghold of iconic species like jaguars, giant armadillos, harpy eagles and tapirs. The region is a UNESCO World Heritage Site and one of BirdLife International’s key areas for bird preservation.

The biological reserve covers 27,800 hectares (68,700 acres) and is part of a forest mosaic stretching from northern Espírito Santo to the far south of Bahia state, a region called the Hiléia Baiana. Unusually, traces of Amazonian flora and fauna can be found here, in the middle of the Atlantic Rainforest, despite the two biomes being separated by approximately 1,500 kilometers (930 miles).

Macuco Lake, seen from atop one of the lookouts covered by the forest. Image by Leonardo Merçon.

Vestiges of the Amazon inside the Atlantic Rainforest

In between the Amazon and Atlantic rainforests are two other biomes: the Cerrado savanna and Caatinga shrubland. Numerous clues suggest that the rainforests were connected in the past. Pollen samples, stalactites and stalagmites show that forest was present some 900 to 20,000 years ago where the Caatinga exists today.

A study by Henrique Batalha Filho, a professor of biogeography at Bahia Federal University’s Institute of Biology, shows the two rainforests were linked at two different points in history. The first time was during the Miocene Epoch (between 5 million and 24 million years ago), where the Cerrado lies today in Mato Grosso state and in the transition zone of the Chaco dry forest in Paraguay and Bolivia. This encounter may have been associated with tectonic events.

The second time was more recent, during the Pliocene and Pleistocene (between 11,5000 and 5 million years ago) in the Caatinga and Cerrado in northeastern Brazil. The contact that time was due to climate change that promoted the expansion of gallery forests — which radiate out from rivers and wetlands into drier areas — toward the interior of South America’s Arid Diagonal. This stretch of landscape is formed by the Caatinga, the Cerrado and the Chaco, and the spread of forests allowed for the exchange of species between the Amazon and Atlantic rainforests.

Map showing where the Amazon and Atlantic rainforests may have been linked in the past. The earlier linkage, which may have occurred up to 24 million years ago, was in the south, and the more recent one (as late as 11,500 years ago) was further north. Image courtesy of Henrique Batalha Filho.

Amazonian species found in Sooretama

Many of the species found in Sooretama Biological Reserve are the same as those found in the Amazon. One is the spot-legged wood turtle (Rhinoclemmys punctularia). Scientists previously believed that in South America, the species was only found in the Amazon.

Another example is the collared trogon (Trogon collaris), a bird found throughout the Amazon but only in a tiny sliver of the Atlantic Rainforest in northern Espírito Santo and southern Bahia. Other Amazonian birds can also be seen in Sooretama, such as the brown-winged schiffornis (Schiffornis turdina), the thrush-like wren (Campylorhynchus turdinus), the little tinamou (Crypturellus soui), and one of the world’s largest raptors, the harpy eagle (Harpia harpyja).

The spot-legged wood turtle (Rhinoclemmys punctularia) is a species found mainly in the Amazon and a few of the best-preserved parts of the Atlantic Rainforest. Image by Leonardo Merçon.
The collared trogon (Trogon collaris) normally nests in holes in termite mounds or trees. It’s found throughout the Amazon and in the Atlantic Rainforest’s Mata de Tabuleiro region. Image by Leonardo Merçon.

Other animals have undergone a process known as speciation — evolving over the course of thousands or millions of years in response to the different conditions in the Amazon and Atlantic forests. Thiago Silva-Soares, a researcher at the Herpeto Capixaba Project who studies Brazilian reptiles and amphibians, says speciation can involve the gradual transformation of a species into an entirely new one.

“The species are split by a physical barrier, in this case the Arid Diagonal, which keeps the populations apart,” he says. “At some point, they will be so different that they will no longer manage to crossbreed, either because they are incompatible, or because they no longer recognize each other as the same species.”

One possible example of this is the red-billed curassow (Crax blumenbachii). There are several curassow species distributed throughout Brazil, most of them native to the Amazon. But the red-billed curassow is found only in the Atlantic Rainforest, in the small protected forests of southern Bahia and northern Espírito Santo. Most occur in the area formed by Sooretama Biological Reserve, Vale Natural Reserve, and smaller private reserves nearby like the Cupid Farm and Refuge. The bird’s population in the wild today is estimated at 500.

The species has become a symbol for the importance of preserving the region, and its survival has been attributed to the presence of these refuges in the middle of what has otherwise become an extensively degraded biome. Animals like these are important not only because of their biological value but also for the local economy. Birdwatchers the world over are drawn to the private reserves around Sooretama to see these rare treasures of the Brazilian forests.

There are an estimated 500 red-billed curassows (Crax blumenbachii) left in the wild, all in the forests lying between northern Espírito Santo and southern Bahia states in Brazil. Image by Leonardo Merçon.

Threat posed by a highway

While there has been a marked increase in sightings of rare animals over the past decade, Sooretama Biological Reserve is feeling the effects of nearby populated areas and highways.

It’s estimated that more than 20,000 wild animals are hit and killed each year on the approximately 25-km (15-mi) stretch of the BR-101 highway that runs through the reserve and its surroundings. In all, some 150 different species of vertebrates have been killed, including amphibians, reptiles, birds and mammals. Many are endangered species, like the jaguar, puma and tapir.

One case in point is bats. The reserve lies in a region that boasts a large diversity of the animals, with 70 identified species — 60% of which have been reported as roadkill. In one incident, a new species of bat was described for the first time from an animal that was killed on the highway.

BR-101 runs through Sooretama Biological Reserve and is the main roadway connecting Espírito Santo and southern Bahia. Image by Leonardo Merçon.

Aureo Banhos dos Santos, a professor of biology at Espírito Santo Federal University’s Roadway Ecology Project, says the greatest concern related to this protected area is the possibility that the highway may be widened. “BR-101’s impact is critical not only due to the number of wild animals killed by traffic, but also because it would be a vector for increased occupation in the region, intensified land use, greater impact on the forest, deforestation in the fragments surrounding the reserve and competition for water resources,” he says. “Easy access and increased population also bring another serious threat to local fauna: commercial hunting.”

The university project’s trail cameras have documented poaching by individuals armed with cutting-edge technology. Together with the Public Prosecutor’s Office (MPF), the Roadway Ecology Project team is seeking out measures to minimize the highway’s impact.

“It was, in a way, a bad idea from the start, built in that scenario of environmental legislation under the dictatorship, for which there was neither planning nor environmental impact studies,” Banhos says. “At the time, the reserve had been in existence for 30 years already. It remains to be seen what its future will be like with regard to the highway.”

School students are also being engaged in efforts to raise awareness of the importance of the biological reserve. The Curupira Project, named after a mythical guardian of the forest, aims to transform young people into defenders of the wild. As they learn more about the region where they live, they begin to experience a change in their perceptions about the forest. But the work of raising awareness doesn’t stop with the younger generation. Older inhabitants of the area can also learn more about the region’s diversity and the environmental issues around them.

Plans to widening the BR-101 highway could lead to an increase in roadkill in the region. Image by Leonardo Merçon.

 
Banner image of forested area inside Sooretama Biological Reserve, by Leonardo Merçon.

Additional reporting by Suzana Camargo.

This story was first reported by Mongabay’s Brazil team and published here on our Brazil site on Oct. 29, 2020.