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A giant ecosystem can suddenly collapse

A giant ecosystem can suddenly collapse

Thanks to their large size, giant ecosystems like the Amazon rainforests are relatively impervious to environmental stress compared to smaller ones. Or so we tend to think.

However, a new study published in the journal Nature disproves this assumption. A larger and more complex ecosystem may be more prone to sudden collapse than a smaller one once environmental and climatic factors have passed a tipping point.

A team of researchers behind the study came to this conclusion after examining the relationship between the size of an ecosystem and the speed with which it collapses in dramatic "regime change." Their findings have yielded disturbing insights.

"Regime changes can abruptly affect hydrological, climatic and terrestrial systems, leading to degraded ecosystems and impoverished societies," the authors write. "Large systems tend to change more slowly than small systems but disproportionately faster," they add, based on results from five computer models.

Even in human life, a vast ecosystem like that of the Amazon could fall apart. Dramatic changes in large ecosystems around the globe could “occur on 'human' time scales of years and decades, meaning that the collapse of large vulnerable ecosystems, such as the Amazon rainforest and the coral reefs of the Caribbean, can take only a few decades to complete. once it is activated ”, warn the scientists.

Initially, as can be expected, the larger and more biologically complex ecosystems are more resistant than the smaller and simpler ones. However, past a point of no return, they collapse faster as a result of a devastating effect on all their constituent parts.

A vast ecosystem like the Amazon rainforests could collapse in just half a century, while stressed coral reefs in the Caribbean could collapse in just a decade and a half.

Impressed by their scale, size, and geological age, we can be misled into thinking that large ecosystems are extremely resilient and can recover from the ravages of environmental stress. However, such an illusion of permanence is deceptive, experts warn.

"Humanity now needs to prepare for changes in ecosystems that are faster than we had previously envisioned through our traditional linear view of the world, including the largest and most iconic ecosystems on Earth and the socio-ecological systems they support," they say.

By Daniel T. Cross. article in english

Video: The great death of insects. DW Documentary ecology documentary (October 2020).