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The discontinuous geographic distribution pattern of plants in the north temperate zone has been a focus of biogeographic research, especially concerning the mechanisms behind the formation of such a pattern and the spatial and temporal evolution of this intermittent distribution pattern. Hypotheses of boreotropical origin, land bridge migration, and out‐of‐Tibet have been proposed to explain the formation of the discontinuous distribution pattern. The distribution of Lonicera shows a typical Europe–Asia–North America discontinuous distribution, which makes for a good case study to investigate the above three hypotheses. In this study, we inferred the phylogeny based on plastid genomes and a nuclear data set with broad taxon sampling, covering 83 species representing two subgenera and four sections. Both nuclear and plastid phylogenetic analyses found section Isika polyphyletic, while sections Nintooa, Isoxylosteum, and Coelxylosteum were monophyletic in subgenus Chamaecerasus. Based on the nuclear and chloroplast phylogeny, we suggest transferring Lonicera maximowiczii and Lonicera tangutica into section Nintooa. Reconstruction of ancestral areas suggests that Lonicera originated in the Qinghai–Tibetan Plateau (QTP) and/or Asia, and subsequently dispersed to other regions. The aridification of the Asian interior may have facilitated the rapid radiation of Lonicera in the region. At the same time, the uplifts of the Tibetan Plateau appear to have triggered the spread and recent rapid diversification of the genus on the QTP and adjacent areas. Overall, our results deepen the understanding of the evolutionary diversification history of Lonicera. [ABSTRACT FROM AUTHOR]

The climate of the Tibetan Plateau is influenced by the monsoons and the Westerlies due to land-sea thermal contrasts. However, few quantitative temperature reconstructions have been made for the region, and this hinders our ability to validate climate models and to understand the coupling process between monsoon, ocean and ice sheets through time. Here we report a quantitative temperature reconstruction for the last deglaciation from a terrace of Lake Dangxiong Co in the southwestern Tibetan Plateau. Based on the unsaturation index of long-chain alkenones, the reconstructed mean annual air temperature during the late Last Glacial Maximum was about 0.2 °C, while the Bølling/Allerød (B/A) period was characterized by a rapid increase in temperature from 0.8 °C to 2.4 °C, (2.9) followed by an abrupt decrease in temperature to −0.9 °C in the early Younger Dryas (YD). The alkenones and n -alkanes record indicates that Dangxiong Co experienced a cold and wet climate in the early part of the last deglaciation after the Last Glacial Maximum, a warm-dry B/A, and a cold and dry YD. Our temperature reconstruction confirms that the thermal and dynamical effects of the Tibetan Plateau are one of the main elements contributing to abrupt changes in the Indian Summer Monsoon. [ABSTRACT FROM AUTHOR]

n‐Alkanes are widely used in paleoenvironmental reconstructions. However, our understanding of changes in the distribution of n‐alkanes with climatic and environmental factors remains unclear in arid/semi‐arid regions. We sampled 26 surface sediments from three climatic zones across the southwestern Tibetan Plateau to evaluate the sensitivity of chain length distributions of n‐alkanes to climatic and environmental parameters. Our observations demonstrate that average chain length (ACL), proportion of aquatic macrophyte (Paq), carbon preference index (CPI) and ratio of the contents of nC27 and nC31 (nC27/nC31) are all sensitive to hydroclimatic conditions. In contrast to commonly‐adopted assumptions, the correlations between these indices and hydrological parameters are not always good, which indicates that the interpretation of n‐alkane indices is special on the southwestern Tibetan Plateau. These might be related to the vegetation characteristics and seasonality of biological activity, and need to be considered in paleoclimatic reconstruction. The impact of seasonal precipitation on n‐alkanes indices was also evaluated. [ABSTRACT FROM AUTHOR]

Knowledge of the origin of past climatic variations on annual to decadal timescales is important for assessing the likelihood of the occurrence of similar variations in the future. Here we present a high-resolution (82-μm) element record, obtained using Synchrotron Radiation X-ray Fluorescence, from the sediments of Toson Lake in the northeastern Tibetan Plateau. The record, which spans the last ∼1100 yr, exhibits variability on an annual to decadal scale. The results of principal component analysis of the element dataset indicates that the first three principal components reflect variations in detrital inputs (via runoff and possibly eolian activity), drought conditions and temperature variations, respectively. Spectral analysis of samples scores on these components reveals strong El Niño-Southern Oscillation (ENSO)-like variability at periods of 3–8 years which indicates that the regional climatic variability was effected by ENSO events over the last ∼1100 yr. On the centennial time scale, the element data and TOC record suggest a warm and dry climate during the Medieval Warm Period (MWP) and a cold and wet Little Ice Age (LIA). The early 20th century was a warm interval, and drier than the LIA but wetter than the MWP. [ABSTRACT FROM AUTHOR]