• Tropical forests can regrow within decades, with species abundance and diversity recovering quickly, but full ecological recovery—especially the return of original species composition—takes much longer.
• Many mobile species such as birds, bats, and bees persist or return early, helping drive regeneration by dispersing seeds and pollinating plants, while slower-moving or long-lived species lag behind.
• Forests may regain high numbers of species relatively fast, but the specific mix of old-growth species takes decades or longer to reassemble, meaning a regrown forest is not the same as the one that was lost.
• Recovery depends on time, prior land use, and proximity to intact habitat, suggesting that protecting and allowing secondary forests to regenerate can be a practical and cost-effective path for restoring biodiversity.