How Climate Change and Human Actions Are Changing Tibet’s Grasslands

Scientists once believed that having many different plant species in grasslands kept food supplies steady. The idea was that if some plants struggled, others would thrive, balancing things out. But new research shows this doesn’t always work when climate change and human activity push ecosystems to their limits.On the Tibetan Plateau, extreme weather and land use are making plants react in the same way at the same time. Instead of acting independently, species now rise and fall together, weakening the natural safety net biodiversity provides. The real game-changer seems to be the soil. Stable soil conditions are holding this shift together, while sunlight also plays a bigger role than rain or temperature in keeping the ecosystem running. Because of these changes, grasslands now depend on a few tough plant species to survive tough conditions. This new strategy—called "core defense"—replaces the old idea that diversity alone protects ecosystems. It’s a big shift in how science views nature’s resilience.