The Ten Year Plan to Save GLTs
AMLD employee Mateus Nunes monitoring the growth of native-tree seedlings planted a year ago in what will become a forest corridor.
Photo credit - Luiz Thiago de Jesus/AMLD 2022
Through international collaborations and robust computer modeling for species survival, conservationists have developed short-term and long-term goals to support the well-being of golden lion tamarins in their native habitat in the Atlantic Forest of Brazil.
It was just about 40 years ago, this small monkey species was nearing extinction in the wild. Through the decades, as conservation partnerships strengthened across the globe and as scientists gained more knowledge about animal care and wildlife reintroductions, the GLT population slowly increased with the species being downlisted from critically endangered to endangered by the International Union for Conservation of Nature and Natural Resources’ Red List of Threatened Species.
GLT conservation goals for 2025, 2028 and 2035 were developed by Save the Golden Lion Tamarin (SGLT), its Brazilian partner Associação Mico Leão Dourado (AMLD), and other international partners during a two-week gathering in August 2024 in Brazil where participants examined recent GLT population census data to develop the plan of action.
2025: Connecting forest fragments
“Our goal for 2025 is at least one population of GLTs which is big enough to have an excellent probability of survival and an excellent retention of genetic diversity,” said James Dietz, vice president and founding director of SGLT. “And when we get to that point, the future for golden lion tamarins will look very, very good.”
About 10 years ago, GLT conservationists set a goal of having at least 2,000 GLTs living in 25,000 hectares (62,000 acres) of connected and protected forest by 2025. That goal was based on scientific research that determined the necessary conditions for ensuring the long-term survival of the wild population.
But currently, there are an estimated total of 4,800 GLTs living in six small and isolated Atlantic Forest fragments. Each of the six isolated forest fragments is too small to hold 2,000 GLTs – a viable population.
To help reach this goal, AMLD and SGLT, with the support of donors, have been planting trees to form forested corridors that connect isolated forested fragments to form larger areas that will have space for about 2,000 GLTs.
The forest corridors are formed by planting native tree seedlings and caring for them until they can survive on their own, which takes about three years. Work is already underway on one of the corridors, named after Jennifer Mickelberg, a career conservationist, AMLD advisor and SGLT board member who passed away in 2023.
The reforestation not only helps GLTs and all other forest inhabitants, it also helps people. It preserves the regional watershed providing water for local communities and it boosts the local economy by providing forest-friendly jobs. Additionally, forest restoration benefits everyone by mitigating climate change.
Dietz said that although much progress has been made, it will likely take a few more years to meet this 2025 goal given unanticipated setbacks such as yellow fever disease in GLTs and construction of an interstate toll road through GLT habitat. That’s why attention is being directed to the next stage in the GLT Atlantic Forest conservation plan.
“We’re almost, almost there,” Dietz said.
Photo Credit: JM Dietz, 2024
Photo Credit: Luiz Thiago de Jesus/AMLD, 2022
When golden lion tamarins use both of these young forest corridors, AMLD will reach its 2028 goal of two viable GLT populations.
2028: Supporting two viable populations
This stage seeks to protect and reinforce two new forest corridors that each connect two large forest areas. Each of the two areas would support between 2,200-2,400 GLTs – two viable populations. Those two large forested areas are located side-by-side.
Work will also focus on supporting genetically diverse populations of GLTs. That means translocation interventions will occur for the remaining populations in smaller isolated forest fragments. This requires scientists to move unrelated GLTs into forest areas with small populations to prevent inbreeding and to support the species’ health.
“We need bigger populations in order to have robust genetic diversity that can face future challenges,” Dietz said.
Andréia Martins, AMLD meta team coordinator and decades-long employee, said the translocation efforts are challenging. Scientists and conservationists first have to identify which GLT groups will be translocated and where. Then, they need to capture the entire group of GLTs to be translocated. After being translocated, Andréia’s team will need to monitor the group to see how they adapted to the new location and if there were changes in the composition of the groups.
Having larger connected forests will decrease the need for translocations, Martins said. “I think this connection is important because it will allow the monkeys and other animals to move from one forest fragment to another with less risk of losing their life along the way and this will increase the genetic flow between populations, avoiding problems of inbreeding between them,” she said.
Children are planting trees as part of an educational activity in AMLD's GLT EcoPark.
Photo credit - Photo by Luiz Thiago de Jesus/AMLD 2023
2035: Forming one large forest
The long-term goal is to have more than 4,000 GLTs living in one large, uninterrupted forested area of about 50,000 hectares (123,550 acres). GLT conservation efforts for the 2025 and 2028 goals, including the growth and protection of the forest corridors, will support progress toward this 2035 target.
Dietz emphasizes that GLTs in the smaller, isolated forest areas are also a priority in this overall strategy. “We don’t want to leave any population behind,” said Dietz, adding that some of those GLTs are descendants of zoo-born GLTs and are valuable to the genetic diversity of the species.
Dietz and other scientists and conservationists feel optimistic about the work ahead and the benefits it will bring GLTs, as well as other species. Already, there have been indications of increased puma and harpy eagle activity in the area, as indicated by reports from AMLD field staff and camera monitors.
“We’re really putting these ecosystems back together,” Dietz said.
Supporters of this work around the world can help these efforts by visiting their local accredited zoos and learning about the ways zoos directly support animal conservation in the wild. Supporters can also donate directly to SGLT’s Grow Trees for GLTs where 100% of contributions go directly toward growing the corridors connecting the forest fragments. Unrestricted contributions support other tasks needed to reach SGLT and AMLD’s long-term goals, such as vaccinating GLTs to prevent yellow fever, providing equipment to track and count GLTs, and supporting the management of the wild population.