Nature published a study showing that tropical forests can recover 90% of their plant and animal diversity within 30 years if left to regenerate naturally, though full recovery takes much longer and composition returns more slowly than abundance. This matters because tropical forests cover only 40% of their original extent — the research demonstrates that protecting regenerating secondary forests, not just pristine old-growth, is critical for reversing biodiversity loss. The study tracked 16 species groups and found that mobile animals like seed dispersers bounce back faster than trees, suggesting ecosystem function can partially restore even when species composition lags.