The biodiversity of the Himalaya,Hengduan Mountains and Tibet,here collectively termed the Tibetan Region,is exceptional in a global context.To contextualize and understand the origins of this biotic richness,and its ...The biodiversity of the Himalaya,Hengduan Mountains and Tibet,here collectively termed the Tibetan Region,is exceptional in a global context.To contextualize and understand the origins of this biotic richness,and its conservation value,we examine recent fossil finds and review progress in understanding the orogeny of the Tibetan Region.We examine the deep-time origins of monsoons affecting Asia,climate variation over different timescales,and the establishment of environmental niche heterogeneity linked to topographic development.The origins of the modern biodiversity were established in the Eocene,concurrent with the formation of pronounced topographic relief across the Tibetan Region.High(>4 km)mountains to the north and south of what is now the Tibetan Plateau bounded a Paleogene central lowland(<2.5 km)hosting moist subtropical vegetation influenced by an intensifying monsoon.In mid Miocene times,before the Himalaya reached their current elevation,sediment infilling and compressional tectonics raised the floor of the central valley to above 3000 m,but central Tibet was still moist enough,and low enough,to host a warm temperate angiosperm-dominated woodland.After 15 Ma,global cooling,the further rise of central Tibet,and the rain shadow cast by the growing Himalaya,progressively led to more open,herb-rich vegetation as the modern high plateau formed with its cool,dry climate.In the moist monsoonal Hengduan Mountains,high and spatially extensive since the Eocene but subsequently deeply dissected by river incision,Neogene cooling depressed the tree line,compressed altitudinal zonation,and created strong environmental heterogeneity.This served as a cradle for the then newly-evolving alpine biota and favoured diversity within more thermophilic vegetation at lower elevations.This diversity has survived through a combination of minimal Quaternary glaciation,and complex relief-related environmental niche heterogeneity.The great antiquity and diversity of the Tibetan Region biota argues for its conservation,and the importance of that biota is demonstrated through our insights into its long temporal gestation provided by fossil archives and information written in surviving genomes.These data sources are worthy of conservation in their own right,but for the living biotic inventory we need to ask what it is we want to conserve.Is it 1)individual taxa for their intrinsic properties,2)their services in functioning ecosystems,or 3)their capacity to generate future new biodiversity?If 2 or 3 are our goal then landscape conservation at scale is required,and not just seed banks or botanical/zoological gardens.展开更多
The growth of the Qinghai-Tibetan Plateau(QTP)during the Cenozoic drove dramatic climate and environmental change in this region.However,there has been limited comprehensive research into evolution of climate during t...The growth of the Qinghai-Tibetan Plateau(QTP)during the Cenozoic drove dramatic climate and environmental change in this region.However,there has been limited comprehensive research into evolution of climate during this interval.Here we present a quantitative reconstruction using Bioclimatic Analysis(BA)and Joint Probability Density Functions(JPDFs)based on data available for 48 fossil floras,including macrofossils and palynological fossils collected in the QTP area from the Paleogene to Neogene(66–2.58 Ma).Both methods indicate that there was an overall decline in temperature and precipitation.Paleoclimatic simulations using Hadley Centre Coupled Model version3(HadCM3)show that the most prominent climate change was very likely driven by QTP orographic evolution from the late Eocene,which was accompanied by a shift in temperature from a latitudinal distribution to a topographically controlled pattern.In addition,with the growth of the QTP,temperature and precipitation decreased gradually in the northeastern part of the plateau.Different sources of evidence,including plant fossil records,climate simulations and other proxies,indicate that the topographic evolution of the QTP and other geological events,in conjunction with global cooling,may have been the main factors driving climate change in this region.This research can provide insights into Cenozoic environmental change and ecosystem evolution.展开更多
基金XTBG International Fellowship for Visiting Scientists to R.A.S.the NSFCeNERC(Natural Environment Research Council of the United Kingdom)joint research program[nos.41661134049 and NE/P013805/1]。
文摘The biodiversity of the Himalaya,Hengduan Mountains and Tibet,here collectively termed the Tibetan Region,is exceptional in a global context.To contextualize and understand the origins of this biotic richness,and its conservation value,we examine recent fossil finds and review progress in understanding the orogeny of the Tibetan Region.We examine the deep-time origins of monsoons affecting Asia,climate variation over different timescales,and the establishment of environmental niche heterogeneity linked to topographic development.The origins of the modern biodiversity were established in the Eocene,concurrent with the formation of pronounced topographic relief across the Tibetan Region.High(>4 km)mountains to the north and south of what is now the Tibetan Plateau bounded a Paleogene central lowland(<2.5 km)hosting moist subtropical vegetation influenced by an intensifying monsoon.In mid Miocene times,before the Himalaya reached their current elevation,sediment infilling and compressional tectonics raised the floor of the central valley to above 3000 m,but central Tibet was still moist enough,and low enough,to host a warm temperate angiosperm-dominated woodland.After 15 Ma,global cooling,the further rise of central Tibet,and the rain shadow cast by the growing Himalaya,progressively led to more open,herb-rich vegetation as the modern high plateau formed with its cool,dry climate.In the moist monsoonal Hengduan Mountains,high and spatially extensive since the Eocene but subsequently deeply dissected by river incision,Neogene cooling depressed the tree line,compressed altitudinal zonation,and created strong environmental heterogeneity.This served as a cradle for the then newly-evolving alpine biota and favoured diversity within more thermophilic vegetation at lower elevations.This diversity has survived through a combination of minimal Quaternary glaciation,and complex relief-related environmental niche heterogeneity.The great antiquity and diversity of the Tibetan Region biota argues for its conservation,and the importance of that biota is demonstrated through our insights into its long temporal gestation provided by fossil archives and information written in surviving genomes.These data sources are worthy of conservation in their own right,but for the living biotic inventory we need to ask what it is we want to conserve.Is it 1)individual taxa for their intrinsic properties,2)their services in functioning ecosystems,or 3)their capacity to generate future new biodiversity?If 2 or 3 are our goal then landscape conservation at scale is required,and not just seed banks or botanical/zoological gardens.
基金supported by the Basic Science Center for Tibetan Plateau Earth System(Grant No.41988101)the Yunnan Province Natural Science Foundation(Grant No.2019FB061)+2 种基金the Second Tibetan Plateau Scientific Expedition and Research Program(STEP,Grant No.2019QZKK0705)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB26000000)the National Natural Science Foundation of China(Grant No.41772026)。
文摘The growth of the Qinghai-Tibetan Plateau(QTP)during the Cenozoic drove dramatic climate and environmental change in this region.However,there has been limited comprehensive research into evolution of climate during this interval.Here we present a quantitative reconstruction using Bioclimatic Analysis(BA)and Joint Probability Density Functions(JPDFs)based on data available for 48 fossil floras,including macrofossils and palynological fossils collected in the QTP area from the Paleogene to Neogene(66–2.58 Ma).Both methods indicate that there was an overall decline in temperature and precipitation.Paleoclimatic simulations using Hadley Centre Coupled Model version3(HadCM3)show that the most prominent climate change was very likely driven by QTP orographic evolution from the late Eocene,which was accompanied by a shift in temperature from a latitudinal distribution to a topographically controlled pattern.In addition,with the growth of the QTP,temperature and precipitation decreased gradually in the northeastern part of the plateau.Different sources of evidence,including plant fossil records,climate simulations and other proxies,indicate that the topographic evolution of the QTP and other geological events,in conjunction with global cooling,may have been the main factors driving climate change in this region.This research can provide insights into Cenozoic environmental change and ecosystem evolution.
