Research press release


Nature Geoscience

Ancient Maya deforestation impacted soil carbon stores



Peter Douglasたちは、マヤ低地の土壌中の有機炭素の残存期間の過去3500年にわたる変化を、ろう(植物の葉が産生し、湖の堆積物に保存されていたもの)の年代を基に調べた。その結果、ろうの土壌中の残存期間は、土地利用が集中的に行われていた時期に減少し、マヤ文明の人口密度が低下していくつかの地域で土壌管理の実践を始めるにつれて回復し始めたことが見いだされた。しかし、炭素の残存は森林伐採が始まる前のレベルにまで回復することはなく、このような土壌は、そこを覆う植生が回復した後も炭素をあまり隔離できないことが示唆される。


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.

doi: 10.1038/s41561-018-0192-7


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