Biologists led by Bettina Engelbrecht of the Smithsonian Tropical Research Institute in Panama looked at the distribution of 48 species of trees and shrubs, growing in study plots on the Panamanian isthmus.

The 122 plots ranged from damp Caribbean to dry Pacific slopes.

Where trees and shrubs grew depended crucially on how resistant they were to drought during the local dry season, they found.

Rainforests are commonly thought of as saturated places, but the true picture is complex.

Even though temperatures are relatively stable in tropical regions, water availability and local soil moisture can vary a lot and over small distances.

These differences are expected to amplify under global warming, which will change rainfall patterns and the duration of rainy seasons, making some places wetter and other places drier.

"Our research shows that changes in rainfall patterns will have considerable consequences for tropical forests," said co-author Ben Turner in a press release.

In tropical rainforests where global warming lengthens the dry season and where human development has already fragmented forest lands, the outcome could be "loss of diversity and perhaps species extinction," said University of Utah biologist Tom Kursar.

The study appears on Thursday in the British journal Nature.

All rights reserved. copyright 2018 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.