Cenozoic topography,monsoons and biodiversity conservation within the Tibetan Region:An evolving story  

作　　者：Robert A.Spicer Alexander Farnsworth Tao Su 

机构地区：[1]CAS Key Laboratory of Tropical Forest Ecology,Xishuangbanna Tropical Botanical Garden,Chinese Academy of Sciences,Xishuangbanna 666303,China [2]School of Environmental,Earth and Ecosystem Sciences,The Open University,Walton Hall,Milton Keynes,MK76AA,UK [3]School of Geographical Sciences,University of Bristol,Bristol,BS81SS,UK

出　　处：《Plant Diversity》2020年第4期229-254,共26页植物多样性（英文版）

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]。

摘　　要：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 imp

关 键 词：Tibet HIMALAYA Hengduan Mountains Landscape FOSSILS Conservation 

分 类 号：Q16[生物学—普通生物学]