Ancient Maya deforestation impacted soil carbon stores

The amount of time that carbon remained stored in soils in Guatemala and the Yucatan Peninsula was shortened by deforestation undertaken by the ancient Maya, reports a paper published online this week in Nature Geoscience. This finding suggests that deforestation in similar tropical regions could affect the ability of the underlying soils to sequester carbon.

Soils contain large amounts of organic carbon, which can be sequestered from the atmosphere for thousands of years or more. Disturbances to any overlying vegetation are thought to impact this carbon storage, but the effects may vary by the type of soil and the nature of the interference.

Peter Douglas and colleagues assess changes in the lengths of time that carbon persisted in soils in the Maya Lowlands over the last 3,500 years by determining the ages of waxes produced by plant leaves and preserved in lake sediments. They find that the amount of time the waxes remained in the soils decreased during periods of intensive land use, and began to recover as Maya population density fell and some regions began using soil management practices. The carbon durations never recovered to the levels seen prior to deforestation, however, suggesting that these soils were less able to sequester carbon even after the overlying vegetation recovered.

In addition, the authors find that deforestation over the past 150 years has further reduced soil carbon persistence at some of the study sites.