Overview
- Research in an Ecuadorian rainforest reports that after about 30 years of natural regrowth, secondary forests reach roughly 90% of old-growth abundance and diversity and about 75% of species composition.
- Birds, bats, and bees return early and speed plant recovery by dispersing seeds and carrying pollen across the landscape.
- Trees, leaf‑litter animals, and soil microbes recover much more slowly due to long lifespans, limited movement, and the rarity of many old-growth specialists.
- Recovery trajectories depend on past land use and connectivity, with cacao legacies rebounding faster than pasture and nearby intact forest supplying colonists that accelerate return.
- Natural regrowth can restore biodiversity at low cost if forests are left to mature, yet intact old-growth remains irreplaceable even as secondary forests now cover about 70% of the tropics.