- Brown spider monkeys (Ateles hybridus) are some of the world’s most threatened primates, as deforestation has razed about 85% of their habitat in Colombia.
- With monkey populations living in patches of forests, conservationists in the Middle Magdalena region feared that low genetic variation could lead to a further collapse of the species, so they started creating biological corridors connecting forest fragments.
- The project currently maintains 15 ecological corridors, with plans to create six more. Researchers work with landowners to create private conservation areas, leveraging the benefits of forest restoration for agriculture and ecosystems in general.
In Colombia’s Middle Magdalena region, a patchwork of forest corridors is linking up isolated populations of the critically endangered brown spider monkey (Ateles hybridus). Composed of native and fruit-bearing trees, these corridors on the margins of agricultural land and along riverbanks are providing a lifeline to this species and others, enabling them to move between isolated forest fragments.
Around 600 hectares (1,480 acres) of forest providing habitat for the brown spider monkey in the Middle Magdalena are being connected by 15 ecological corridors, created by conservationists Andrés Link and Gabriela de Luna. Their NGO, Fundación Proyecto Primates (the Primates Project Foundation), aims to add another six corridors and connect a total of 2,000 hectares (4,940 acres) of forest across the region.
“We’ve used the brown spider monkey as an umbrella species,” Link says. “We believe that working for the brown spider monkey is helping the entire biological community in this really diverse area of central Colombia.”
Reversing fragmentation
The brown spider monkey, also known as the variegated spider monkey or Choibos locally in Spanish, is one of the world’s most threatened primates.
Over the past few decades, the middle Magdalena saw two waves of deforestation and land use change; more than 50 years ago, cattle ranching arrived, followed by oil palm plantations that have intensified in the last 15 years and continue to expand. Remaining forest patches that were spared in the first wave, such as in mountainous areas or wetlands, are now threatened by oil palms, biologist de Luna says.
Brown spider monkeys rely on pristine forests, but deforestation has led to the loss of as much as 85% of their habitat across their range, while their population has declined mostly in relation to that, Link says. The monkeys also have low reproductive cycles. Females begin reproducing at around 7 years old and birth only one infant every three years or so. Compounding that threat, the species is hunted in some local communities for meat and medicinal purposes or kept as pets.

Link and de Luna first came up with the idea of connecting the remaining patches of monkey habitat when, during surveys, they discovered albino brown spider monkeys in a forest fragment nearby the San Juan River.
They say they believed low genetic diversity to be at play due to inbreeding among the isolated population. “We thought if we want these monkeys to survive in the long term, we really need to provide some sort of connectivity to the forests,” Link says.

Around 2014, they began planting a few small corridors along the riverbanks of the San Juan River to connect several forest patches. To their surprise, vegetation rebounded quickly. They also saw that these benefited other species, not only brown spider monkeys. In a few years, other species of spider monkeys, howler monkeys, opossums and porcupines began using the corridors.
Building bridges for monkeys with landowners
In order to close the gaps in the monkeys’ habitat, Link and de Luna had to make agreements with private landowners allowing them to create forest connections on the margins of cattle ranches or along riverbanks.
That’s not always been easy, Link and de Luna explain. Some landowners are keen to support their effort, while others do not see the benefit. Ultimately, it often comes down to concerns over financial losses. A long history of political and social conflict in the area, where illegal groups remain active, means that trust has been earned over years of work building relationships with both landowners and community members.

“Conservation is very hard,” de Luna says. A lot of effort may be put in to protect a 60-hectare [150-acre] piece of land, only for a neighboring farmer to burn a forest area nearby. It’s an ever-present risk that a vital habitat may disappear. “Sometimes, things like that happen,” she says.
“We’re trying to use those early adopters who started to work with us to provide successful stories about how conservation can improve the landscape and also their productivity in their cattle ranches and agricultural fields,” Link says.
Link and de Luna emphasize that the corridors provide more than conservation benefits, as restoring forest areas can protect water sources, securing water availability for cattle ranches in the face of climate change. “We discuss with every landowner, one on one, where we should put these corridors,” Link tells Mongabay.

The foundation is also in the process of establishing private nature reserves — so far seven parcels of land covering roughly 1,000 hectares (about 2,470 acres) of forest are going through the process — and is working with local and regional authorities on possible tax incentives for landowners who carry out conservation on their land. But that’s a slow and challenging process. “We think that by joining people who are keen on conservation, we will create a critical mass that might be able to influence local politics,” de Luna says.
Ultimately, they say it is a model that could be scaled up across Colombia and beyond. Link’s project has recently earned him a Whitley Award from the Whitley Fund for Nature, a UK charity that supports grassroots conservation across the Global South.
Felipe Alfonso-Cortes and Nathalia Fuentes, co-directors of Project Washu in Ecuador’s Esmeraldas province, which aims to protect another endangered primate, the brown-headed spider monkey (Ateles fusciceps), studied under Link and de Luna at the outset of the brown spider monkey project.

“Observing how they have worked to create biological corridors in collaboration with landowners has been a true source of inspiration,” Alfonso-Cortes and Fuentes write in an email to Mongabay. Their own project works closely with cacao farmers to create wildlife corridors. “Seeing the results [of the brown spider monkey project] after years of effort, how vegetation structures are restored and how species begin to move more safely between forest fragments is something truly remarkable and brings hope.”
Engaging communities
In a region beset by recent political and social conflict, and with illegal activities such as mining and logging taking place, it was difficult to win the confidence and the trust of local people at first, de Luna says. That took time going door to door and working with children’s groups.
Yorlady, a former teacher in the Bocas del Carare community and a member of Asomucare, a local women’s association, explains how the project has shifted the mindset of local people. It started with school workshops that have taught children more about nature and the brown spider monkey.
“The knowledge that children shared with adults is also important, as it’s helped people to love the biodiversity that we have in this community and municipality,” Yorlady says. In her view, that’s shifted perspectives from one of consumption to conservation of local wildlife.
Before the project began, some people in the community kept brown spider monkeys as pets, caught river turtles or consumed their eggs. But that’s no longer the case for the majority of people, she says.

Link and de Luna’s team also started a local festival dedicated to the brown spider monkey and other wildlife (El festival del Choibo y sus amigos by its Spanish name), now in its 10th year of existence, with a large impact on awareness and changing attitudes toward protecting biodiversity.
Now, the team plans to expand its workshops to other local schools and expand their current wildlife monitoring and forest restoration projects. One aim is to support community tree nurseries by offering training and capacity building so locals can grow and sell trees for restoration efforts.
Colombia plans to invest heavily in forest restoration, Link says. “We want local communities to be prepared to fill that gap now, so that they can sell the trees,” he says. “So they can actively do the restoration.”
Yorlady says she is hopeful that others in the region will join in conserving the rich biodiversity of the Middle Magdalena. “If we conserve the brown spider monkey, we preserve all the biodiversity around it,” she says.
Citation:
De Luna, A. G., & Link, A. (2018). Distribution, population density and conservation of the critically endangered Brown spider monkey (Ateles hybridus) and other primates of the inter-andean forests of Colombia. Biodiversity and Conservation, 27(13), 3469-3511. doi:10.1007/s10531-018-1611-1
Banner image: The critically endangered brown spider monkey (Ateles hybridus). It’s estimated that the species, one of the world’s top 25 endangered primates, has lost up to 85% of its habitat. Image courtesy of Andrés Link.
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