نتایج جستجو برای: aridification
تعداد نتایج: 280 فیلتر نتایج به سال:
The modern Antarctic Dry Valleys are locked in a hyper-arid, polar climate that enables the East Antarctic Ice Sheet (EAIS) to remain stable, frozen to underlying bedrock. The duration of these dry, cold conditions is a critical prerequisite when modeling the long-term mass balance of the EAIS during past warm climates and is best examined using terrestrial paleoclimatic proxies. Unfortunately,...
The extant snake fauna has its roots in faunal upheaval occurring across the Paleogene-Neogene transition. On northern continents, this turnover is well established by the late early Miocene. However, this transition is poorly documented on southern landmasses, particularly on continental Africa, where no late Paleogene terrestrial snake assemblages are documented south of the equator. Here we ...
The Qinghai-Tibetan Plateau (QTP) has become one of the hotspots for phylogeographical studies due to its high species diversity. However, most previous studies have focused on the effects of the Quaternary glaciations on phylogeographical structures and the locations of glacial refugia, and little is known about the effects of the aridization of interior Asia on plant population structure and ...
Caragana, with distinctive variation in leaf and rachis characters, exhibits three centers of geographic distribution, i.e., Central Asia, the Qinghai-Tibetan Plateau (QTP), and East Asia, corresponding to distinct biomes. Because Caragana species are often ecologically dominant components of the vegetation in these regions, it is regarded as a key taxon for the study of floristic evolution in ...
Approximately 34 million years ago across the Eocene-Oligocene transition (EOT), Earth's climate tipped from a largely unglaciated state into one that sustained large ice sheets on Antarctica. Antarctic glaciation is attributed to a threshold response to slow decline in atmospheric CO2 but our understanding of the feedback processes triggered and of climate change on the other contents is limit...
The Tibetan Plateau uplift and Cenozoic global cooling are thought to induce enhanced aridification in the Asian interior. Although the onset of Asian desertification is proposed to have started in the earliest Miocene, prevailing desert environment in the Tarim Basin, currently providing much of the Asian eolian dust sources, is only a geologically recent phenomenon. Here we report episodic oc...
Despite the recent focus on phylogenetic niche conservatism in macroevolutionary studies, many clades have diversified widely along multiple niche dimensions. The factors underlying lineage-specific niche lability are still not well understood. We examined morphological and climate niche evolution in Montiaceae (Caryophyllales), an ecologically variable plant lineage distributed primarily along...
Abstract Earth’s climatic evolution over the last 5 million years is primarily understood from perspective of marine mechanisms, however, role terrestrial feedbacks remains largely unexplored. Here we reconstruct soil moisture variability in Central Asia using paleomagnetism data and isotope geochemistry an 80 m-thick sedimentary succession at Charyn Canyon, Kazakhstan. We identify a long-term ...
The Amazon forest is increasingly vulnerable to dieback and encroachment of grasslands agricultural fields. Threats these forested ecosystems include drying, deforestation, fire, but feedbacks among make it difficult determine their relative importance. Here, we reconstruct the central western tree cover response aridity fire in mid-Holocene—a time less intensive human land use markedly drier c...
Abstract Rapid climate change was a major contributor to the end-Permian extinction (EPE). Although well constrained for marine realm, relatively few records document pace, nature, and magnitude of across EPE in terrestrial environments. We generated proxy chemical weathering land surface temperature from continental margin deposits high-latitude southeastern Gondwana. Regional simulations prov...
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