Amazon Rainforest Faces Drought, but Could Fight Against Dry Conditions

Dry conditions may impact the Amazon rainforest in the future. Yet it seems like this biodiverse region may be able to handle potential drought better than expected. Scientists have discovered that, provided forest conservation measures are in place, the Amazon rainforest should be able to withstand periods of drought.

In previous studies, climate models have over predicted the water stress that plants feel during the dry season. This is because they don't take into account the moisture that the forest itself can recycle in times of drought. In this new model, though, the scientists removed the unrealistic water stress and found that the moisture that is recycled by the forest is sufficient to reduce the intensity of drought conditions.

Moisture recycling includes the full cycle of rain. It mainly depends on water both evaporating from the ground and moving through plants from the roots to the leaves. It's an important source of rainfall over the Amazon forest. In fact, about one-third of the annual rainfall in the southern Amazon forest can originate from moisture recycling.

"This study suggests that forests are not only more able to withstand droughts than we had previously thought, but it is the response of the forest itself that can reduce the intensity or length of the drought," said Anna Harper, one of the researchers, in a news release. "Moisture recycling works best in large areas of undisturbed forest so it is essential that measures to protect the Amazon rainforest are in place to ensure that this natural process can be maintained in what may be a drier climate in the future."

The moisture recycling relies heavily on the ability to plants to actually access soil moisture. Previously, researchers believed that during particularly severe droughts, trees reach a limit in their ability to access and use soil moisture. Yet scientists have found that, in reality, moisture recycling can increase during the dry season and can result in increased atmospheric moisture. This can reduce the water stress felt by the forest plants.

That said, drought is likely to become a larger problem in the future. Conserving these forest areas will be crucial to helping them survive. Large areas of undisturbed forests are more able to maintain moisture recycling, which means that cutting up forests should be avoided.

The findings are published in the Journal of Climate.