Planned since the 1950s, Marginal de la Selva is a US$1 billion highway project that would create a paved land passage through the Andean foothills in Colombia’s Amazon region. The highway, when complete, would allow land cargo to cross South America from the Atlantic to the Pacific without having to enter the Andes Mountains, opening an enticing trade route from Venezuela to Ecuador through Colombia.

While the majority of the road project has been completed, there is still one particularly sensitive stretch that has yet to be finished: a section that passes between two of the country’s national parks. As expectations for the road project rise, rates of deforestation have soared, and the zone is now one of eight “deforestation hotspots” in the country, giving rise to concerns about the project’s possible impacts on the parks.

Colombia is the world’s second-most biodiverse country after Brazil. In particular, the foothills of the Andes and the nearby transition zone between the Amazon and the eastern plains regions known as the Amazonian piedmont — where the Marginal de la Selva is being routed —contains exceptionally high levels of biodiversity even for Colombia, according to the country’s national parks authority, Parques Nacionales.

To the south of the projected highway is Chiribiquete Natural National Park, almost the size of Belgium and the largest protected area in the Amazon. Known for its unusual elevated rock formations and ancient indigenous art dated to 18,000 BC, the park is also rich in biodiversity, housing 41 species of reptiles, 49 amphibians, 145 birds and at least 13 threatened mammals, as well as four indigenous groups that are believed to remain in isolation.

Even closer to the planned highway, across the Guayabero River, sits Serrania de la Macarena National Park, which protects an independent mountain range that connects three of Colombia’s most biodiverse regions: Amazon, Andes and eastern plains.

La Macarena National Park is also home to the Caño Cristales River, one of the most famed water bodies on the planet. Known as the “river of five colors,” the Caño Cristales is home to a unique species of plant called Macarenia clavigera that for a few weeks per year explodes into a living rainbow of gold, olive green, blue, black and red that contrasts vividly below the water’s crystal surface.

Despite the region’s level of biodiversity, it has never been comprehensively surveyed. Andrew Crawford, associate professor in the Department of Biological Sciences at University of the Andes, told the environmental science website Mongabay, that researchers are only now starting to conduct studies and collect specimens.

“Researchers are just now finally arriving to study the migratory and endemic species found near the Macarena National Park,” said Crawford, who explained that years of internal conflict and guerrilla presence had kept scientists at bay.

However, Crawford said that the improvements in security conditions that are attracting scientists are also bringing the road development:”It’s a race between biologists and development to see who’s going to get there first.”

In September 2016, Edersson Cabrera, the director Colombia’s meteorological institute IDEAM, told El Tiempo newspaper that he had satellite imagery demonstrating that the forest corridor connecting la Macarena to the Amazon and Chiribiquete is disappearing at an alarming rate, with only 2.6 kilometers of direct connection remaining.

“Fauna and flora populations pass through these forests. Right now, there is only one direct connection because the rest of the Amazonian piedmont was lost years ago,” said Cabrera. “The only connection remaining is the area of the Marginal de la Selva, in San Jose del Guaviare, but it has been disappearing,” Cabrera said. “Only a 2.6km area of forest is left directly connecting the Amazon and the Andes, but it’s possible that space has been reduced over the course of the year.”

One of the species threatened by the road development is the jaguar, which needs large tracts of land and strong connections between populations. According to Cabrera, the deforestation in the Marginal de la Selva region “is a threat for the movement of species such as the jaguar, due to the fragmentation of the lower Colombian Andes and their connection with the Amazon.”

The Marginal de la Selva highway is part of President Juan Manuel Santos’ Master Intermodal Transport Plan. A major feature of Colombia’s post- conflict plan to integrate remote regions of the country into the national economy, the plan has a cost of approximately $3.5 billion per year, or 1.3% of the country’s GDP in 2015.

With the country set on improving its agricultural economy, one of the main goals of the national transportation plan is to allow semi-trucks to travel 60 kilometers per hour in the mountains and 80 kilometers on at land. In a statement released by INVIAS, the road will “benefit first and foremost rural producers including projects such as industrial agriculture, petroleum, trade and social development.”

Environmentalist and sustainability expert Rodrigo Botero has been working for the past five years with his non-proflt organization FCDS in the region between the town of Macarena and San José del Guavaire where the Marginal de la Selva highway is planned.

Botero explained that while informal roads built by farmers have existed in the area for decades, the Guaviare department has recently been under- taking “small bridge and drainage projects” in the area as part of its regional development plan. The projects have caused “deforestation to shoot up exponentially,” said Botero.

Alerted to the deforestation in this migratory corridor by IDEAM’s satellite imagery, the environmental government agency Corporation for Sustainable Development of the North-East Amazon (CDA) has ordered local construction on the road to be ceased until an environmental license is issued for the Marginal de la Selva highway project. CDA Director César Meléndez claims illegal armed groups are contributing the increased deforestation across the region.

This article is part of a Creative Commons licence and a longer version appears on Mongabay.com. Taran Volckhausen is a freelance journalist based in Medellín.