Rio de Janeiro has launched a project to repopulate the animal species that have become extinct in the Tijuca National Park, which extends across a good part of this Brazilian city and is considered to be the world's largest urban forest, gradually reintroducing into the green space individual animals currently in captivity.
The initiative entered a new phase on Monday with the release in the middle of the park at the foot of the famous Sugarloaf Hill 14 guinea pigs, which reach 66 centimeters (26 inches) in length and stand 36 cm (14 in.) high and are native to Latin America's tropical jungles and used to be commonly found in Rio's forested areas.
The release of the guinea pigs was carried out as part of the Refauna project headed by the Federal University of Rio de Janeiro (UFRJ), which seeks to reintroduce native species to the Tijuca National Park "with the aim of restoring the local fauna and ecological interactions."
Despite the fact that its 3,953 hectares (about 1,580 acres) contain a rich diversity of plant species, the park in Rio has had its animal species severely reduced due to centuries of deforestation and hunting.
The priority for the project's leaders is reintroducing animal species that are important distributors of seeds, like guinea pigs howler monkeys, tortoises and blue and yellow macaws.
Biologist Catharina Kreischer, the coordinator for Refauna and a researcher with the UFRJ, told EFE that guinea pigs are important because they bury assorted large seeds to eat later and often forget where their caches are, thus allowing new trees to grow.
Kreischer said that the Tijuca park has suffered from significant deforestation in past centuries, with the original vegetation being replaced with coffee plantations and later being reforested but without the presence of the typical animals, who had fled or been hunted out.
"Even with the reforestation, since it's in the middle of the city, those species can't get here without human help to repopulate the forest and fulfill their role as distributors of seeds and (engaging in) other ecological interactions which help to rebuild the forest," she said.
Kreitscher said that since it was launched in 2010, the Refauna project has reintroduced 30 guinea pigs into the park which are monitored with collars that send radiotelemetry to scientists who follow their movements and habits.
She added that during the 1960s there was a similar project in operation in Tijuca but, since there were no animal monitoring programs at the time, those animals have disappeared without a trace.
Currently, there are about 40 guinea pigs in the park that have been born since the releases started, and project workers have noted a significant increase in tree growth as a result.
She also said that the howler monkeys that have been released are fitting into their normal ecological niche as seed distributors.
Kreitscher said that the Refauna project over the next six months will continue to release dozens of tortoises and macaws that are currently being held in captivity at the Rio Zoo.
The repopulation effort will increase public interest in the Tijuca park, which is one of Rio's biggest tourist attractions and the most visited ecological preserve in Brazil, with about three million visitors per year.