Expedition to southeast Suriname uncovers 60 new species — and untold natural wealth

As part of a recent Rapid Assessment Program (RAP) survey of a previously unexplored area of southeastern Suriname, CI’s Trond Larsen was part of a team that discovered 60 species that are likely new to science — and shed new light on the value that this region holds for people.
As rain relentlessly pounds down for the second straight day, our bedraggled team of field biologists peers warily at the rising water beside our makeshift camp. The once-sluggish Palumeu River we had regularly been crossing by traversing a fallen tree had already risen several feet, swallowing our haphazard bridge.
Our campsite occupies a narrow stretch of flat land, blocked by the river on one side and a steep hill on the other. Enjoying solitude in the forest, I had pitched my tent in a secluded riverside spot far from the main camp — a decision I now deeply regret.
Have you ever seen an image of the famous meeting of “black” (dark, tannin-filled) and “white” (light brown, muddy) rivers in South America? To my dismay, the same stunning contrast is developing along the single route to my tent, except that in this case, the “white” water originates from our now inundated latrine.
By nightfall, it becomes clear that sleeping in tents is no longer an option. As I wade through the flooded forest in the dark, I step into a deep hole, and yelp in surprise just before my entire head disappears beneath the water. After regaining my footing, I slog the rest of the way to my tent and drag it up the hillside into a tangle of vines where it will not be swept away by the river.
Back at the camp, I hastily string up a hammock, as does the rest of our team. We all sleep restlessly, just inches above the still rising water. On the positive side, this makes it possible for the fish biologists to collect data without even leaving the comfort of their hammocks!
By morning, there is no question that we need to evacuate the camp and move on to our next site earlier than planned. We load the boats and cruise through the forest, floating along what had previously been our hiking trails! (See video below.) Eventually we reach higher ground, where a helicopter, which had fortunately just been repaired after breaking down earlier on our expedition, carries us to our next camp.
As our adventure demonstrates, water is a plentiful, but also critically important resource in Suriname. Much of the nation’s fresh water originates in southeastern Suriname, the most remote and pristine part of the country, and arguably of the world.
Here, a series of mountain ranges encompass the headwaters that provide the fresh water used by more than 50,000 people downstream in Suriname and French Guiana. This source of clean water is essential for direct consumption, food (particularly fish), sanitation and transportation, as well as supporting a green development strategy for Suriname around sustainable agriculture, energy production and mining.
To better understand the biological and social significance of this unexplored wilderness, CI sent a team of biologists and indigenous guides on a three-week expedition as part of our Rapid Assessment Program (RAP).
We scoured the forest for flowering plants, frogs, snakes, birds, bats, insects, monkeys and other creatures. We installed automated camera traps to photograph elusive wildlife such as wild cats, and dragged nets through rivers and swamps in search of fish.
We also measured the role of these ecosystems in providing benefits to people — quantifying how much carbon its forests absorb to regulate climate, testing water quality and surveying sources of wild food.
Overall, our team found that the region’s forests and freshwater habitats are incredibly pristine, and support a vast wealth of biodiversity, including many species directly beneficial to people. Among the more than 1,300 species of plants and animals we encountered on the expedition, we found 60 species that are probably new to science, including 11 fishes, six frogs, one snake and many insects.
With many frog species rapidly disappearing around the globe, we were surprised and uplifted to discover so many frogs potentially new to science, including a stunningly sleek “cocoa” tree frog. Among the new fishes, we found a gorgeous, miniature tetra with a golden body and red eyes, similar to the head-and-tail-light tetra so popular among aquarists.
We also found that southeastern Suriname is biologically unique, supporting many restricted-range species that may not occur elsewhere, in part due to their associations with isolated mountain ranges. The region also provides a biological corridor for species that move between adjacent transboundary protected areas and indigenous lands, making it essential for the long-term persistence of these species.
However, despite the region’s thriving wildlife, we were startled to find that even in the absence of any upstream mining, the mercury levels in sediments and in fish were slightly above acceptable international standards for human consumption. It appears most likely that this mercury pollution was deposited there via winds from neighboring countries. This demonstrates that even the most isolated and pristine parts of the world are not entirely sheltered from human impacts — all systems are interconnected.
As a field biologist passionate about wilderness, I love nothing more than trekking around some of the world’s most pristine and remote areas in search of awe-inspiring species both familiar and unknown. However, protecting these areas isn’t just important for the frogs and bugs that live there.
In addition to fresh water, the forests of southeastern Suriname regulate the local climate, store carbon that helps to mitigate global climate change, and provide essential services that people depend upon such as food, medicines and building materials.
By ensuring that wilderness areas such as southeastern Suriname remain pristine, we are not just protecting unique biodiversity, but also ensuring a better quality of life for millions of people around the world.
While we continue to explore and discover new forms of life, we are still only beginning to decipher the often mysterious and complex ways in which natural ecosystems have supported civilizations since ancient times — and how we can help them continue to do so.
Trond Larsen is the director of CI’s Rapid Assessment Program (RAP). RAP seeks to guide conservation priorities and decision-making through targeted rapid assessments of biodiversity and ecosystem services at field sites around the world.