The contribution of fire to the late Miocene spread of grasslands in eastern Eurasia (Black Sea region)
The contribution of fire to the late Miocene spread of grasslands in eastern Eurasia (Black Sea region)
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DOI：
10.1038/s41598-019-43094-w
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发表时间：
2019-05-01
影响因子：
4.6
通讯作者：
Vasiliev, Iuliana
中科院分区：
文献类型：
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作者：
Feurdean, Angelica;Vasiliev, Iuliana
草原遍布全球，但控制其生态和进化的过程仍不清楚。人们对火灾对于祖先 C-3 草原扩张的作用知之甚少。在这里，我们提出了第一个基于黑海晚中新世至更新世（类似于 10-1.9 Ma）木炭形态（草、草本、木材）的生物质燃烧记录，并测试了火灾事件的范围及其在欧亚大陆东部开阔草地栖息地崛起中的作用。我们发现，从中新世晚期到上新世（8.5-4.6 Ma），在逐渐寒冷且有时干燥的气候下，地表火灾和树冠火灾的混合机制加速了森林向开放林地的转变，并维持了更易燃的生态系统。火灾状况的临界点发生在 4.3 Ma（上新世中期），当时日益寒冷和干燥的条件导致草原和地表、低强度的枯枝落叶火灾占主导地位。我们通过强调火是欧亚草原的重要生态因素，提供了 C-3 植物进化的替代机制。这项研究开辟了草原进化史研究的新方向，可以用火灾化石记录、气候和植被以及动态植被模型进行测试。
Grasslands are globally extensive, but the processes governing their ecology and evolution remain unclear. The role of fire for the expansion of ancestral C-3 grasslands is particularly poorly understood. Here we present the first biomass combustion record based on late Miocene to Pleistocene (similar to 10-1.9 Ma) charcoal morphologies (grass, herbs, wood) from the Black Sea, and test the extent of fire events and their role in the rise of open grassy habitats in eastern Eurasia. We show that a mixed regime of surface and crown fires under progressively colder and, at times, drier climates from the late Miocene to Pliocene (8.5-4.6 Ma) accelerated the forest to open woodland transition and sustained a more flammable ecosystem. A tipping point in the fire regime occurred at 4.3 Ma (mid-Pliocene), when increasingly cold and dry conditions led to the dominance of grasslands, and surface, litter fires of low intensity. We provide alternative mechanisms of C-3 plant evolution by highlighting that fire has been a significant ecological agent for Eurasian grasslands. This study opens a new direction of research into grassland evolutionary histories that can be tested with fossil records of fire alongside climate and vegetation as well as with dynamic vegetation modells.