A new study suggests the destruction of tropical rainforests is having an even greater impact on the surrounding environment than was previously feared.
Scientists say heavy deforestation in Brazil is causing palm trees to produce smaller seeds, which are less likely to regenerate.
Researchers looked at palm tree seeds collected from the South American country's Atlantic rainforest, the BBC reports.
They say the seeds found in areas that had suffered heavy deforestation were smaller in size and weaker. They believe this was caused by the loss of large birds, such as toucans, which vanished when trees were felled.
With only the smaller birds left, the palm trees evolved to produce fruits that a tinier beak could handle. This adaptation meant the seeds were still dispersed, but the trade-off reduced the chances of them germinating.
Brazil's Atlantic rainforest was once home to a vibrant array of plants and animals. But with the arrival of sugar and coffee plantations in the early part of the 19th Century, it was rapidly destroyed and today, just 12% of the original forest remains.
The study is published in the journal Science.