If put under the kind of environmental stress increasingly seen on our planet, large ecosystems such as the Amazon rainforest or the Caribbean coral reefscould collapse in just a few decades, according to a study released today in Nature Communications. In the case of Amazon forests, stressors could cause collapse in just 49 years. In Caribbean coral reefs, it could take as little as 15 years. “The messages here are stark,” said lead researcher John Dearing, a professor in physical geography at the University of Southampton, in a statement. Those estimates come from Dearing and colleagues who examined data on how 42 natural environmentssmall and large, and on both land and waterhave transformed. They found that larger ecosystems may take longer than small ones to collapse, but the rate of their decline is much more rapid. Ecosystem stress can come in many forms such as climate change, deforestation, overfishing, pollution and ocean acidification. “Humanity now needs to prepare for changes in ecosystems that are faster than we previously envisaged through our traditional linear view of the world, including across Earth ‘s largest and most iconic ecosystems, and the socialecological systems that they support,” the authors wrote. Larger ecosystems are made up of smaller “sub-systems” of species and habitats, which provide some resilience against rapid change. However, once these smaller systems start to collapse, the new study finds the large ecosystems as a whole fall apart much faster than previously expected. Researchers pointed to the destructive Australian and Amazon rainforest wildfires as recent examples of this dangerous fast rate of collapse. “These findings are yet another call for halting the current damage being imposed on our natural environments that pushes ecosystems to their limits,” Dearing added.
ehn.org, 11 Mach 2020