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AMAZON NOT SO WETLAND!
13/06/2024
We think of the Amazon basin as a vast wetland of tropical forest as in my photo and, if you have been there, you will have memories of the mighty river and its lakes and tributaries set in a rainforest so large that, even when you fly over it, the trees stretch as far as you can see in every direction, albeit with increasing areas of clearance and roads. It is half the size of Europe and the Earth’s largest carbon sink.
The Amazon area does have wetter and drier seasons, especially noticeable in the upper catchments, with large variations in water levels and seasonal vegetation change, but current research is showing that the region is now subject to more intense droughts from which recovery is sluggish, causing stress to the vegetation and the ecosystem generally[1]. The research was based on satellite imagery and revealed that some 37% of the rainforest was affected, with concern that it may reach a point of no return.
As if the Amazon’s problems of road building, logging and forest clearance for agriculture are not enough already, anthropogenic climate change is now causing vegetation mortality from dehydration as a result of these prolonged droughts. The ecological adverse impact revealed by the research was found to have more to do with the intensity of the droughts than their frequency, but it was the combination of frequency with intensity that was the most destabilising for the forest. There are also obvious concerns that the tipping point suggested for the trees into a new, drier state for the forest, will inevitably extend to lower vegetation strata below the tree canopy monitored by the satellite images.
The Amazon may seem remote from our day-to-day work at Betts Ecology of managing greenspace for our local biodiversity in the UK, but as the well-known ecological adage goes “everything is connected to everything else” and the breakdown of the Amazonian ecosystem would likely presage global ecological collapse events far away as tipping points are breached. It makes the protection of the Amazon a vital and urgent priority in our battle against the climate catastrophe now upon us. Local people are working hard to this end but it is an uphill battle against loggers, agriculture and climate breakdown.
[1] Van Passel, J., Bernardino, P.N., Lhermitte, S. & Somers, B. (2024). Critical slowing down of the Amazon forest after increased drought occurrence. https://doi.org/10.1073/pnas.2316924121.
