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The study of fire history and driving mechanisms at long time scales can provide a theoretical background for future fire management in forested regions. The alpine lake sediments from Daye Lake in the Qinling Mountains, east‐central China, were used to explore the influence of climate, vegetation and human activity on fires since the LGM, based on charcoals and black carbon. During the last glacial period, fire activity was mostly controlled by regional aridity under a weak East Asian summer monsoon, while human‐induced fires were commonly dominated in the late Holocene. Fire activity was found to be linked to biomass through temperature variability. The biofuel dominated by conifers induced high intensity fires in the last glacial, and herbs contributed more to the high fire frequency over the mid‐late Holocene. With predicted future rising temperatures, increased vegetation cover and extreme climate events may increase the fire risk in the region. Plain Language Summary: Fire activity has an important influence on climate changes and carbon cycling. Understanding past fire history and its driving mechanisms are essential to mitigate the impact of fires. Here, we present fire records from alpine lake sediments in the Qinling Mountains since the LGM. Results indicate that climatological drought under a prevailing weak East Asian summer monsoon increased fire activity during 21.6–11.7 cal ka BP, while human‐induced fires became more common in the late Holocene due to land use, for example, the forest clearing for agriculture and the warfare. And high temperature increases fuel loads, resulting in more fires. Moreover, vegetation types with varying biofuel supply also influence fire activity. We suggest that fire risk may increase in the region with future rising temperature. Our results have implications for understanding fire history and management in other transitional vegetation zones globally. Key Points: The prevailing weak East Asian summer monsoon mostly controlled fire activity during the last glacial, whilst human activity became common through the HoloceneThe conifers induced high intensity fires in the last glacial and herbs contributed more to high fire frequency over the mid‐late HoloceneForest resources in east‐central China will face the increased fire risks in the context of global warming and increasing vegetation cover [ABSTRACT FROM AUTHOR]

Clues of climate change on the Alashan Plateau since the last glacial period (40 ka) are important for revealing the mechanism of desertification of middle-latitude deserts in the Northern Hemisphere (NH). Studies are still rare for the understanding of the specific relationship of climate changes between the Alashan Plateau and the global. Based on a systematic and comparative analysis of the existing research in China and the international academic community, this paper reviews the environmental evolution history of the Alashan Plateau since the last glacial period from the records of paleo-environment and geomorphological characteristics in different deserts of the plateau (e.g., Badanjilin, Tenggeli, and Wulanbuhe). From about 40 ka to the end of the last glacial maximum, the climate on the plateau was wetter than it is today, and to the end of the Pleistocene, the climate was generally dry and the aeolian activities were enhanced. However, the climate was arid during the whole last glacial period in the Wulanbuhe Desert, evidently different from the overall pattern of the plateau. The Tenggeli Desert was characterized by an arid climate in the early Holocene. The most controversial events for the Alashan Plateau are the drought events in the middle Holocene in the Badanjilin Desert. The role and impact of the westerlies and the East Asian Summer Monsoon (EASM) systems on the climate change of the desert and even the whole plateau is a vexed question that brings different views in different periods. There is still a lack of definite evidence representing the events of global environmental change that occurred on the plateau during the discussed period. The distinctive morphology of dune mountains and the distribution of sand dunes are mutually indicative of the direction and energy of wind systems on the plateau. It is suggested that appropriate wind energy is the significant key to the desertification in these middle-latitude deserts on the plateau. From a global-scale review of climate change, the desertification of the modern-scale sandy desert landscapes on the Alashan Plateau is generally related to the global glacial period and the cold and dry climate during the past 40 ka. [ABSTRACT FROM AUTHOR]

To reveal the historical dynamics of the population and existing genetic structure, maternal chloroplast DNA fragments(psbA-trnH, psbI-psbK and psbJ-petA)were used to study the phylogeography of Prinsepia uniflora, a kind of endemic plant distributed in the Loess Plateau. The results were as follows:(1)Total genetic diversity of P. uniflora was high(HT = 0.796), but genetic diversity within species was low(HS= 0.276);(2)The molecular variation analysis(AMOVA)showed that there was a high genetic differentiation within P. uniflora(FST = 0.674), and the genetic variation was mainly between populations(67.4%);(3)Mismatch analysis and MaxEnt based ecological niche simulation results in different historical periods showed that although the core suitable range of P. uniflora did not change much, population still expanded to some extent after the end of the Last Glacial Maximum(LGM). Our study indicated that, like most of the plant groups distributed in the northern regions of China, P. uniflora probably responded to the Quaternary climatic fluctuations by taking refuge nearby or in situ during the glacial period and locally recolonizing in following post-glacial period. [ABSTRACT FROM AUTHOR]

Orographic and climatic oscillations have played crucial roles in shaping the nucleotide diversity and evolutionary history of many species across the Northern Hemisphere. In this study, based on 10 nuclear loci and a chloroplast DNA marker, we analyzed the nucleotide polymorphisms and demographic history of the endangered conifer species Pinus bungeana in Northwest China and investigated the phylogenetic relationships between P. bungeana and two related species, that is, Pinus gerardiana and Pinus squamata. We found that P. bungeana exhibited an extremely low level of nucleotide diversity (πsil = 0.00159). Demographic simulations based on DIYABC analysis showed that P. bungeana underwent demographic expansion and contraction during the Miocene. According to ecological niche modeling, we found that this species survived in situ during the glacial period and was not restricted to southern refugia. We speculate that P. bungeana may have experienced widespread population shrinkage from the Last Interglacial to the Last Glacial Maximum due to geological or climatic events. Isolation‐with‐migration analysis revealed that the divergence (~2.4–4.2 Ma) among P. bungeana and its related species was significantly associated with the Qinghai–Tibetan Plateau uplift events in the mid‐to‐late Tertiary period. Species tree analyses suggested that these three related Pinus species formed a monophyletic clade with high bootstrap support. These results suggest that the Miocene–Pliocene and Pleistocene geological and climatic fluctuations might have profoundly affected the nucleotide diversity and demography of this psychrotolerant conifer species in western China. [ABSTRACT FROM AUTHOR]