Collapse of Earth’s Largest Ecosystems Occurs Faster Than Thought

(CN) – The Amazon rainforest could be the Amazon savanna by 2070, because ecosystems undergo massive, disruptive, structural changes within decades, not millennia, according to new research.

Scientists published their work Tuesday in the journal Nature Communications in which they analysed 42 so-called regime shifts around the world.

“Unfortunately, what our paper reveals is that humanity needs to prepare for changes far sooner than expected,” explained lead author Simon Willcock of Bangor University’s School of Natural Sciences in a statement.

This image shows a Brazil nut tree in Jaú National Park, Amazonas, Brazil. (Victor Caetano-Andrade)

“These rapid changes to the world’s largest and most iconic ecosystems would impact the benefits which they provide us with, including everything from food and materials, to the oxygen and water we need for life,” Willcock said.

Once triggered, regime shifts occur much faster in smaller ecosystems, but at relatively faster rates in larger ecosystems. A small system like the Caribbean coral reefs, which stretch about 7,700 squares miles, could collapse within 15 years. Between ocean acidification, overfishing, and climate change, that mean the Caribbean could lose its coral reefs by 2035.

Once it passes its tipping point, an ecosystem like the Amazon, which spans 1.9 million square miles, can become an entirely different kind of ecosystem.

“Worryingly, recent plot inventories from the Amazon show a declining rate of carbon sequestration, and there is growing evidence that further deforestation and degradation of the feedback between moisture formation and vegetation coverage may lead to a system-wide tipping point as soon as 2021,” researchers wrote in the study.

Real world data input into six different models spanned three time periods, five continents, and three different types of environments, including Florida Bay’s change from a sea-grass dominated environment to algal, the desertification of the African Sahel, and Victoria Park Lake in Australia and its shift from having high oxygen levels that sustained animal life to being so filled with nutrients that plant life choked out all other life.

“We intuitively knew that big systems would collapse more slowly than small ones – due to the time it takes for impacts to diffuse across large distances. But what was unexpected was the finding that big systems collapse much faster than you might expect – even the largest on Earth only taking possibly a few decades,” said author John Dearing from Geography and Environment at Southampton University in a statement.

Although regime shifts can occur naturally as a response to climate or environmental changes, many modern regime shifts are exasperated by, if not directly linked to, human activity.

All hope is not lost. Conservation is always possible. Ecologists and community members can stabilize ecosystems by identifying and protecting keystone species which would leave a disproportionately large hole in the food web if removed.

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