Like Coke versus Pepsi, tropical land ecosystems come in two choices: forest or grassland. New research shows these two options can switch abruptly, and there’s rarely any in-between.
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If so, then many of these ecosystems are particularly vulnerable to future changes such as rising temperature, scientists say. With just slight shifts in rainfall or other factors, people living in what is now tropical rainforest might suddenly find themselves in scrubland populated by a different mix of plants and animals — where people’s livelihoods might have to change dramatically.
“That transition is not going to happen smoothly,” says Milena Holmgren, an ecologist at Wageningen University in the Netherlands. “The evidence is showing there are these big jumps.”