- Worsening climate change creates enormous challenges for ecosystems and individual species. As the world warms, plants and animals must quickly migrate to cooler places to stay resilient and survive. But today such migrations are often blocked by deforestation, human infrastructure and lack of conserved lands.
- In the tropics, vast lowlands can require species to move large distances north or south to escape warming. The most rapid path to climate-resilience is upslope migration, with plants and animals relocating shorter distances uphill to cooler places.
- A new study has mapped major elevational gradients in the Amazon that offer the best possibility for connectivity and upslope relocation in the biome — overlaying elevational gradients, amount of forest cover, fragmentation and protected areas.
- This broad-brush research could aid policymakers in identifying the most viable upslope corridors, helping nations and NGOs target best opportunities for land protection to enhance connectivity and aid species survival.
Amazon-based scientists have long known that rapidly rising temperatures mean that places where species live today won’t be where they live tomorrow. For a vast number of species — ranging from insects, birds and primates to all manner of plants — upslope migration could present a potential, though perilous, pathway to resilience and survival during the climate crisis.
This knowledge has raised a vital question: What are the most likely and best protected routes by which species across the Amazon’s broad expanse can relocate upward, helping preserve biodiversity, and hopefully keeping intact the ecosystem services tropical forests now deliver?
In what is deemed the first region-wide assessment of Amazonia’s climate resilience and connectivity, a new study points to the western part of the biome, particularly the Andean spine of Peru, as the most viable upslope corridors. According to researchers, this region has the highest concentration of key components needed to support species survival — including major elevation gradients, large established protected areas, and connected forested corridors to facilitate upslope species migration.
The scientists pinpointed additional potential corridors in southwestern Colombia, northern Brazil, northern Bolivia, north-central Guyana, and western Suriname. But these areas are disadvantaged due to fewer protected areas, with connectivity in many locales broken by forest fragmentation due to deforestation and oil and gas drilling.
Published in May in the journal Global Ecology and Conservation, the new study, titled “A regional-scale assessment of climate-resilient corridors and connectivity in the Amazon,” was undertaken with the goal of providing findings that could inform conservation planning across tropical South America.
“There is a particularly urgent need to establish climate-resilient corridors in the tropics,” the authors wrote. “Not only is there limited tropical forest remaining for new, large protected areas, but over 62% of tropical forests are no longer connected to future climate [ecosystem] analogues, due to increasing deforestation and habitat fragmentation.”
“However,” the researchers added, “corridors that span large elevational gradients across protected-area networks may represent unrealized opportunities for promoting biodiversity resilience under climate change.”
Manu’s upslope connectivity
One outstanding example of this connectivity can be found in Peru’s mega-biodiverse Manu National Park, located in the country’s southwest Amazon region. Established in 1973, it covers more than 1.7 million hectares (4.2 million acres) of varied topography that is roughly the size of the U.S. state of New Hampshire. Steep, ice-topped gradients peak at 4,000 meters (13,000 feet) and roll down the Andes to the humid, flat plains of the Amazon basin near sea level. Biodiversity here ranks among the highest on Earth in terms of birds, butterflies and plant species.
It’s also an area that has been studied in-depth over two decades. The international Andes Biodiversity and Ecosystem Research Group (ABERG), founded in 2003, has monitored Manu’s upslope species migration practically in real time on one of the largest elevational transects under constant study in the global tropics.
In 2016, research conducted by ABERG members and tropical ecologists Kenneth Feeley and Miles Silman concluded that given the rate of climate change and human threats to protected areas, “the biggest determinant of many species’ extinction risks may be their ability to migrate through unprotected habitats.”
The new study builds on these Peru-based findings, along with a first-of-its-kind study in 2024 that mapped Central America’s climate adaptation biodiversity corridors. The new research seeks to provide a preliminary roadmap for identifying the most advantageous connectivity corridors in Amazonia — a potentially valuable resource for conservationists.
A foundation for policymaking
Study co-author Corine Vreisendorp, director of science for the Amazon Conservation Association, justifies the sweeping new study this way: In the Amazon, “We do not [currently] have an explicit conservation priority for [protecting] elevational gradients. [Our research] is meant to be a call to action to place a priority on [conserving] areas that have elevational gradients. We need to give biodiversity a chance to move upslope.”
Vreisendorp adds, “This is a broad-brush, coarse look at this [climate relocation challenge]. Now we need to have conversations at the country level, even sub-national levels, and ask: What [lands] are we protecting … that have elevational gradients? How do we make [these places a priority]? How do we get the international community and donors focused on this?”
The newly published climate corridor study is extensive, covering the Amazon biogeographic region — spanning eight countries, three macro-level ecological dominions, and 11 more narrowly defined ecological provinces. Analyses emphasized forested areas with wide-ranging elevations, but also included grasslands and lowlands prevalent in the southern and eastern regions of the Amazon.
Using enormous datasets from all 11 ecological provinces, scientists Ian McCullough and Chris Beirne overlayed elevational gradients, forest cover, forest fragmentation and designated protected areas across the vast study area. They also noted areas marked by significant deforestation from logging and ranching, as well as legal oil and gas concessions, and illegal gold mining sites.
This fragmentation — increased further by roads, settlements and other infrastructure — poses the most extensive barrier to intact, forested connectivity corridors that could enable climate-resilient upslope species migration.
Upslope obstacles and opportunities
Silman, a tropical ecologist at Wake Forest University in the U.S. state of North Carolina, installed the elevational transect plots in the Kosñipata Valley of Manu National Park more than 20 years ago. Upslope tree species migration remains a central part of his ongoing research. Despite the compelling image of animals and plants gradually shifting to higher elevations as Earth’s modern climate changes, this natural phenomenon is neither new nor novel.
“The two superpowers that life has, and that’s allowed life to persist through all the past trials and challenges, is the existence of big areas of uninterrupted habitat and the ability of species to move within them as necessary,” Silman says, noting the naturally changing climate occurred at the end of the last ice age 10,000 years ago. “Some argue that species [then] didn’t really experience climate change, because they could move so easily over time to new habitats and stay in equilibrium.”
Such movements have been nature’s encoded survival mechanism in response to evolving climate conditions over millennia. But past species migrations had the luxury of occurring over centuries, allowing time to relocate and reassemble ecosystems. Researchers today recognize that the required pace of migrations now is much faster, and includes lesser understood ecological obstacles that go beyond corridor fragmentation.
“My existential anxiety stems from thinking, okay, you may have species that are able to move up,” Vreisendorp says, “but they are a part of pretty tightly evolved ecosystems.”
She notes that scientists are just beginning to understand multiple complexities. For example, as birds migrate to higher elevations, they may confront unfamiliar predators; likewise, tree species relocating upslope, may encounter differing soils and insects that aren’t as accommodating as in a previous downslope habitat.
At the heart of the problem: Ecosystems don’t migrate as a whole; instead, species relocate piecemeal at variable rates, with less resilient ones likely going extinct. The late renowned conservation biologist Thomas Lovejoy, who coined the term biological diversity, warned that as warming pushes ecosystems beyond their limits, they will “disassemble” and “surviving species will reassemble” into novel, unpredictable, “hard to imagine” combinations.
Species resilience to climate change, not adaptation, will be the key to their survival, says Andrew Whitworth, a tropical wildlife ecologist with the NGO Climate Corridors and a co-author of both the new study and the Central America corridors study. He suggests that many species will fail to adapt. Likewise, resilience will occur differently in different tropical regions, possibly with fewer species able to migrate quickly and far enough — especially in vast lowlands where great distances must be traveled to reach cooler places.
“I am not saying by any means that lowland areas of Brazil or Colombia should be ignored,” for conservation, Whitworth adds. “But in thinking purely from the aspect of improved resilience to climate change, elevational gradients provide the best bet for getting as many species as possible through that bottleneck to the other side. These connected corridors are our lifeboats; we need the policy world to protect those corridors that are strong and healthy. This study provides a great map of what we should be focused on over the next decade.”
Banner image: A howler monkey in the Amazon. As the world warms, plants and animals must quickly migrate to cooler places to stay resilient and survive. Image by Dylan Shaw via Unsplash.
Justin Catanoso is a regular contributor to Mongabay. Disclosure: He is a professor of journalism at Wake Forest University in North Carolina where tropical ecologist Miles Silman is on the faculty.
Citations
McCullough, I.M., Beirne, C., et al. (2026) A regional-scale assessment of climate-resilient corridors and connectivity in the Amazon. Global Ecology and Conservation. doi:10.1016/j.gecco.2026.e04234
McCullough, I.M., Beirne, C., et al. (2024) Mapping climate adaptation corridors for biodiversity — A regional-scale case study in Central America. PLOS One. doi:10.1371/journal.pone.0304756
Feeley, K.J., Silman, M.R. (2016) Disappearing climates will limit the efficacy of Amazonian protected areas. Diversity and Distributions: A Journal of Conservation Biology. doi:10.1111/ddi.12475
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