According to a new study, Amazonian and Andean tree communities are increasingly unable to adapt to increasing temperatures. All of this creates a perfect storm for the longterm overall health of these essential ecosystems. The comprehensive research, which spans over 40 years, indicates that these forests are not successfully migrating to cooler elevations as climate change accelerates.
The study draws upon years of collaborative work of networks such as the Andes Biodiversity and Ecosystem Research Group (ABERG), the Amazon Forest Inventory Network (RAINFOR), and ForestPlots.net. The resulting findings, published in PNAS this week, provide a clear picture of our world and an urgent call to action. We need to better understand the ecological effects of climate change on these highly biodiverse forested landscapes.
Extensive Research Effort
The collaborative research team consisted of over 20 scientists from institutions across the Americas and Europe. Together, they took careful measure of more than 66,000 trees from 2,500 species names in 66 long-term forest plots. It was very much intentional to position these plots along the Amazon-to-Andes elevational transects in Peru and Bolivia. This method allows us to get a big picture of how tree populations are reacting to these changes in climate.
Even after completing such an extensive data collection, researchers were surprised to discover that tree species are not moving their populations upslope in response to warming temperatures. Many communities across the country are finding it hard enough just to catch up with the overwhelming pace of warming trends. This is particularly the case in mid-elevation (1,200–2,000 m) forests.
“These forests are simply not keeping up with climate change.” – William Farfan-Rios
The mid-elevation forests showed the most impactful signs of compositional change, mostly due to higher mortality rates for trees better-suited for cooler environments. The cumulative effect of this trend is profound, with implications for both the integrity and functioning of the ecosystems that these dams destroy.
Implications for Biodiversity and Climate Stability
The findings unveil a troubling reality: the growing climatic debt threatens the integrity of some of the most diverse forests on Earth. Tropical forests of the Andes and Amazon support the highest concentration of biodiversity in the world. They are critical to the health of the planet’s climate. As tree communities lose the ability to shift and acclimatize, researchers predict serious consequences for the world’s ability to store carbon.
If these tree communities are unable to adjust to warming conditions, experts caution that the Andes and Amazon may weaken as global carbon sinks. This would in-directly cause millions of additional metric tons of carbon emissions, worsening the impacts of climate change.
“The result is a growing climatic debt that threatens the integrity and functioning of the most diverse forests on Earth.” – William Farfan-Rios
These findings have implications well beyond short-term ecological impacts. The study underscores the importance of maintaining long-term monitoring efforts to better understand how these forest ecosystems evolve over time.
The Need for Continued Research
Miles Silman, another leading researcher in the study, reiterates the need for long-term monitoring. “You have to be there for long periods of time to understand how these forests change,” he asserts. These perspectives are important for creating impactful conservation strategies. They are our best tool to protect sensitive ecosystems from the escalating impacts of climate change.
Silman expresses valid doubts about whether these forests will be able to maintain that future viability. “If we lose these climate observatories, these natural labs, we blind ourselves to our future,” he warns. The study points to major shifts in forests. These modifications fail to make them much more resilient to the impacts of climate change.
Successful adaptation depends not just on trees but on their animal dispersers and pollinators. Yet habitat loss is pressing in on their numbers at a shocking pace. As a consequence, forest communities can hardly cope with the tide of environmental chaos sweeping across the Andes-Amazon.
“They also need the full complement of animal dispersers and pollinators to help expand their range—and loss of habitat is shrinking their ranks. If you look at the magnitude of changes happening in the Andes-Amazon, the forest communities likely are not going to keep up.” – Miles Silman