近日,,國際著名雜志《科學(xué)》Science在線刊登了過完研究人員的最新研究成果“Intensifying Weathering and Land Use in Iron Age Central Africa”,在這項研究中,,研究者指出了近些年來非洲的雨林衰減的原因,。
大約3000年前,中部非洲的某些雨林突然被稀樹草原取代,;多年以來大多數(shù)的研究人員將這一轉(zhuǎn)變歸咎于氣候的變化,。 但是,一項新的研究提示,,氣候變化本身不會產(chǎn)生如此一種劇烈的轉(zhuǎn)變——而人類肯定也在這一轉(zhuǎn)變中扮演了一個角色,。 Germain Bayon及其同事對采自剛果河河口的海洋沉積物核心進(jìn)行了分析并發(fā)現(xiàn),大約在3000年前,,那里的沉積物已經(jīng)受到了強烈的化學(xué)風(fēng)化的影響,。
這一在該區(qū)域中的以化學(xué)物為基礎(chǔ)的巖石和礦物分解的增加與從相當(dāng)于現(xiàn)在的喀麥隆和尼日利亞地區(qū)的講班圖語的農(nóng)夫的到來時間一致。 這些班圖部落給該地區(qū)帶來了農(nóng)業(yè)和冶鐵技術(shù),,而Bayon及其同事如今提示,,這些早期的農(nóng)夫可能也對中非的雨林帶來了重大的影響。 據(jù)這些研究人員披露,,班圖人在3000年前以砍伐樹木來為農(nóng)業(yè)和冶煉鐵者創(chuàng)建可耕地的時候強化了他們對土地的使用并加劇了土壤的侵蝕過程,。 研究人員說,這些行動以及氣候的變化可能導(dǎo)致了世界上該地區(qū)雨林的衰減,。(生物谷Bioon.com)
doi:10.1126/science.1215400
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Intensifying Weathering and Land Use in Iron Age Central Africa
Germain Bayon*, Bernard Dennielou, Joël Etoubleau, Emmanuel Ponzevera, Samuel Toucanne, Sylvain Bermell
About 3000 years ago, a major vegetation change occurred in Central Africa, when rainforest trees were abruptly replaced by savannas. The consensus is that the forest disturbance was caused by climate change. We show here that chemical weathering in Central Africa, reconstructed from geochemical analyses of a marine sediment core, intensified abruptly at the same period, departing significantly from the long-term weathering fluctuations related to the Late Quaternary climate. Evidence that this weathering event was also contemporaneous with the migration of Bantu-speaking farmers across Central Africa suggests that human land-use intensification at that time already had a significant impact on the rainforest.