澳大利亚詹姆斯库克大学Bird Michael I.研究组报道了晚更新世澳大利亚热带稀树草原人为火灾制度的出现。2024年3月11日出版的《自然—地球科学》杂志发表了这一最新研究成果。
研究通过连续的湖泊记录评估了过去15万年的火灾发生率和强度，比较了植物燃烧过程中形成的微炭和稳定的多环芳烃的累积率。我们还比较了禾草（主要是C4）花粉占旱地花粉总量的百分比，和稳定的多环芳烃的碳同位素组成。研究以高度的统计确定性证明，至少在11000年前，火灾状况发生了变化，从频率较低、强度较高的火灾转变为频率较高、强度较低的火灾。
这一变化标志着一个基本上自然的火灾制度被一个至少由土著管理调整的制度所取代。研究发现表明，在整个全新世，人类对火的使用改变了火的状态，也显示了人们是如何管理未来可能增加的高强度火灾类型的。
研究人员表示，当欧洲人到达澳大利亚大陆时，成熟的土著社会在澳大利亚大陆广阔的热带稀树草原上实行土地管理。火是人们操纵燃料负荷和连通性的主要工具之一，以减少不受控制的野火，维持植被结构和增强生物多样性。然而，“自然”火灾制度是何时转变为人为引起主导的火灾制度尚不清楚。
附：英文原文
Title: Late Pleistocene emergence of an anthropogenic fire regime in Australia’s tropical savannahs
Author: Bird, Michael I., Brand, Michael, Comley, Rainy, Fu, Xiao, Hadeen, Xennephone, Jacobs, Zenobia, Rowe, Cassandra, Wurster, Christopher M., Zwart, Costijn, Bradshaw, Corey J. A.
Issue&Volume: 2024-03-11
Abstract: At the time of European arrival on the Australian continent, sophisticated Indigenous societies practiced land management across Australia’s extensive tropical savannahs. Fire was one of the main tools people used to manipulate fuel loads and connectivity to reduce uncontrolled wildfire, maintain vegetation structure and enhance biodiversity. When this alteration of a ‘natural’ fire regime to a human-dominated fire regime occurred is not known. Here we assessed fire incidence and intensity over the past 150,000years through a continuous lacustrine record by comparing the accumulation rates of micro-charcoal and stable polycyclic aromatic hydrocarbon that form during the combustion of vegetation. We also compared grass (mainly C4) pollen as a percentage of total dryland pollen with the carbon isotope composition of the stable polycyclic aromatic hydrocarbon. We established with high statistical certainty that a change in fire regime occurred at least 11,000years ago from less-frequent, more-intense fires to more-frequent, less-intense fires. This change marked the overprinting of a largely natural fire regime by one at least modulated by Indigenous management. Our findings demonstrate that human fire use has modified fire regimes throughout the Holocene and also show how people have managed the potential for the type of high-intensity fires that are likely to increase in the future.
DOI: 10.1038/s41561-024-01388-3
Source: https://www.nature.com/articles/s41561-024-01388-3