Global warming may be interacting with regional rainfall and deforestation to accelerate forest loss in the Amazon, pushing it towards partial or total collapse.
Research published yesterday in Nature has identified the potential thresholds of these stressors, showing where their combined effects could produce a ‘tipping point’ – in which the forest is so fragile that just a small disturbance could cause an abrupt shift in the state of the ecosystem.
The study was led by the Federal University of Santa Catarina in Brazil and included experts from the University of Birmingham. Its authors hope that by understanding the most important stressors on the rainforest environment, they can develop a pathway for keeping the Amazon forest resilient.
Lead author Bernardo Flores, from the University of Santa Catarina, said: “Compounding disturbances are increasingly common within the core of the Amazon. If these disturbances act in synergy, we may observe unexpected ecosystem transitions in previously considered resilient areas, such as the moist forests of the western and central Amazon.”
These ecosystem transitions could include a forest that may recover but is still trapped in a degraded state and dominated by opportunistic plants such as bamboo and vines or a forest that cannot recover and remains trapped in an open-canopy, flammable state.
The research findings are important because of the Amazon’s vital role in the global climate system. For example, if released, Amazonian trees store massive amounts of carbon, which could accelerate global warming, showing that the Amazon temporarily acted as a carbon sink during the 2015 drought.
Co-author, Dr Adriane Esquivel-Muelbert from the Birmingham Institute of Forest Research, said: “We have evidence showing that rising temperatures, extreme droughts and fires are can affect how the forest functions and change which tree species can integrate the forest system. With the acceleration of global change there’s an increasing likelihood that we will see positive feedback loops in which, rather than being able to repair itself, the forest loss becomes self-reinforced.”
