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Scientists have found that Brazil's coastal forests played a key role in the migration of trees between the Amazon and Atlantic rainforests, providing natural corridors for their movement over millions of years.
The study, conducted by scientists at the Royal Botanic Gardens of Edinburgh (RBGE) and the University of Exeter, found that riverine ecosystems facilitated a constant exchange of species, even despite the presence of significant dry zones between forests. As Dr James Nicholls notes,
This is confirmed by DNA analysis of 164 species of Inga trees, which allowed us to reconstruct their evolutionary history and migration routes.
The scientists identified 16–20 migration events in which Inga trees moved from the Amazon to the Atlantic forests, while the reverse movement was much less frequent. This may be due to the large area of the Amazon, which facilitates the wider distribution of seeds. The analysis showed that the process of settlement was ongoing, and not only during periods of humid climate, as previously thought.
The study's findings highlight the importance of conserving riverine forests, which are protected by Brazilian law. Professor Toby Pennington notes:
With only 20% of the Atlantic rainforest remaining intact, the need to both immediately protect these ecosystems and maintain the natural connections between them in the future is emphasized.
