Publications

Previous studies on large‐scale patterns in plant richness and underlying mechanisms have mostly focused on forests and mountains, while drylands covering most of the world's grasslands and deserts are more poorly investigated for lack of data. Here, we aim to 1) evaluate the plant richness patterns in Inner Asian drylands; 2) compare the relative importance of contemporary environment, historical climate, vegetation changes, and mid‐domain effect (MDE); and 3) explore whether the dominant drivers of species richness differ across growth forms (woody vs herbaceous) and range sizes (common vs rare). Distribution data and growth forms of 13 248 seed plants were compiled from literature and species range sizes were estimated. Generalized linear models and hierarchical partitioning were used to evaluate the relative contribution of different factors. We found that habitat heterogeneity strongly affected both woody and herbaceous species. Precipitation, climate change since the mid‐Holocene and climate seasonality dominated herbaceous richness patterns, while climate change since the Last Glacial Maximum dominated woody richness patterns. Rare species richness was strongly correlated with precipitation, habitat heterogeneity and historical climatic changes, while common species richness was strongly correlated with MDE (woody) or climate seasonality (herbaceous). Temperature had little effects on the species richness patterns of all groups. This study represents the first evaluation of the large‐scale patterns of plant species richness in the Inner Asian drylands. Our results suggest that increasing water deficit due to anthropogenic activities combined with future global warming may increase the extinction risk of many grassland species. Rare species (both herbaceous and woody) may face severe challenges in the future due to increased habitat destruction caused by urbanization and resource exploitation. Overall, our findings indicate that the hypotheses on species richness patterns based on woody plants alone can be insufficient to explain the richness patterns of herbaceous species.

Whether richness patterns and determinants are consistent between common and rare species remains controversial, and the answer is fundamental for the conservation of species in vulnerable habitats. Although effects of climate and geological history on species richness have been widely explored, their relative contribution among common and rare species is poorly understood. Here, using a valuable ornamental plant family Gesneriaceae, we evaluated how contemporary climate, habitat heterogeneity and long-term climate change affect the distribution of rare and common species. Additionally, we identified hotspots of Gesneriaceae diversity and evaluated its protection gap in China.

Analyzing how climate change affects vegetation distribution is one of the central issues of global change ecology as this has important implications for the carbon budget of terrestrial vegetation. Mapping vegetation distribution under historical climate scenarios is essential for understanding the response of vegetation distribution to future climatic changes. The reconstructions of palaeovegetation based on pollen data provide a useful method to understand the relationship between climate and vegetation distribution. However, this method is limited in time and space. Here, using species distribution model (SDM) approaches, we explored the climatic determinants of contemporary vegetation distribution and reconstructed the distribution of Chinese vegetation during the Last Glacial Maximum (LGM, 18,00014C yr BP) and Middle-Holocene (MH, 600014C yr BP). The dynamics of vegetation distribution since the LGM reconstructed by SDMs were largely consistent with those based on pollen data, suggesting that the SDM approach is a useful tool for studying historical vegetation

Ambient energy, niche conservatism, historical climate stability and habitat heterogeneity hypothesis have been proposed to explain the broad-scale species diversity patterns and species compositions, while their relative importance have been controversial. Here, we assessed the relative contributions of contemporary climate, historical climate changes and habitat heterogeneity in shaping Salix species diversity and species composition in whole eastern Asia as well as mountains and lowlands using linear regressions and distance-based redundancy analyses, respectively. Salix diversity was negatively related with mean annual temperature. Habitat heterogeneity was more important than contemporary climate in shaping Salix diversity patterns, and their relative contributions were different in mountains and lowlands. In contrast, the species composition was strongly influenced by contemporary climate and historical climate change than habitat heterogeneity, and their relative contributions were nearly the same both in mountains and lowlands. Our findings supported niche conservatism and habitat heterogeneity hypotheses, but did not support ambient energy and historical climate stability hypotheses. The diversity pattern and species composition of Salix could not be well-explained by any single hypothesis tested, suggesting that other factors such as disturbance history and diversification rate may be also important in shaping the diversity pattern and composition of Salix species.

Is high diversity in tropical and subtropical mountains due to topographical complexity alone or a combination of topography and temperature seasonality? Here, we aim to assess the contribution of these two factors on Rhododendron diversity in China. Specifically, we evaluate how low temperature seasonality in subtropical China jointly with heterogeneous environment accounts for increased species diversity across montane landscapes relative to those of the more seasonal temperate zone in north China.

The Anthropocene is witnessing a loss of biodiversity, with well-documented declines in the diversity of ecosystems and species. For intraspecific genetic diversity, however, we lack even basic knowledge on its global distribution. We georeferenced 92,801 mitochondrial sequences for >4500 species of terrestrial mammals and amphibians, and found that genetic diversity is 27% higher in the tropics than in nontropical regions. Overall, habitats that are more affected by humans hold less genetic diversity than wilder regions, although results for mammals are sensitive to choice of genetic locus. Our study associates geographic coordinates with publicly available genetic sequences at a massive scale, yielding an opportunity to investigate both the drivers of this component of biodiversity and the genetic consequences of the anthropogenic modification of nature.

Aim: Leaf margin states have been found to be strongly related to temperature, and hence have been used to reconstruct palaeotemperatures. Here, we aimed to explore the uncertainties and conditions of use of this technique in China by testing the influences of plant life-form, precipitation and evolutionary history on the relationship between percentage of untoothed species and temperature. Location:China. Methods:Using distribution maps and leaf margin states (untoothed versus toothed) of 10,480 Chinese woody dicots and dated family-level phylogenies, we evaluated the phylogenetic signal of leaf margin state, and demonstrated the variation in the patterns of leaf margin percentage and the relationship with temperature across different life-forms (evergreen and deciduous; trees, shrubs and lianas), regions with different precipitation and species quartiles with different family ages. Results: Significant phylogenetic signals were found for the percentage of untoothed species within families. Relationships between leaf margin percentage and temperature were: (1) weak or insignificant for all woody dicots, shrubs, evergreen and deciduous dicots, but strong for trees and lianas; (2) significantly enhanced with increasing precipitation, and (3) significantly weakened for trees belonging to old families. Main conclusions: Our results showed the complete leaf margin spectrum found in China and revealed great uncertainties in its relationship with temperature induced by life-form, precipitation and evolutionary history. These findings suggest that analysis of leaf margins for palaeotemperature reconstruction should be done cautiously: (1) only dicot trees with a relatively young family age can be used and their leaf margin states are more strongly affected by winter cold than by mean annual temperature; (2) the transfer function between leaf margin percentage and temperature is only reliable in humid and semi-humid regions of China.

Ecological communities that experience stable climate conditions have been speculated to preserve more specialized interspecific associations and have higher proportions of smaller ranged species (SRS). Thus, areas with disproportionally large numbers of SRS are expected to coincide geographically with a high degree of community-level ecological specialization, but this suggestion remains poorly supported with empirical evidence. Here, we analysed data for hummingbird resource specialization, range size, contemporary climate, and Late Quaternary climate stability for 46 hummingbird–plant mutualistic networks distributed across the Americas, representing 130 hummingbird species (ca 40% of all hummingbird species). We demonstrate a positive relationship between the proportion of SRS of hummingbirds and community-level specialization, i.e. the division of the floral niche among coexisting hummingbird species. This relationship remained strong even when accounting for climate, furthermore, the effect of SRS on specialization was far stronger than the effect of specialization on SRS, suggesting that climate largely influences specialization through species' range-size dynamics. Irrespective of the exact mechanism involved, our results indicate that communities consisting of higher proportions of SRS may be vulnerable to disturbance not only because of their small geographical ranges, but also because of their high degree of specialization.

Forest canopy height is an important indicator of forest biomass, species diversity, and other ecosystem functions; however, the climatic determinants that underlie its global patterns have not been fully explored. Using satellite LiDAR-derived forest canopy heights and field measurements of the world's giant trees, combined with climate indices, we evaluated the global patterns and determinants of forest canopy height. The mean canopy height was highest in tropical regions, but tall forests (>50 m) occur at various latitudes. Water availability, quantified by the difference between annual precipitation and annual potential evapotranspiration (P−PET), was the best predictor of global forest canopy height, which supports the hydraulic limitation hypothesis. However, in striking contrast with previous studies, the canopy height exhibited a hump-shaped curve along a gradient of P−PET: it initially increased, then peaked at approximately 680 mm of P−PET, and finally declined, which suggests that excessive water supply negatively affects the canopy height. This trend held true across continents and forest types, and it was also validated using forest inventory data from China and the United States. Our findings provide new insights into the climatic controls of the world's giant trees and have important implications for forest management and improvement of forest growth models.

Ethnopharmacological relevance The rich floral and ethnic composition of eastern Nepal and the widespread utilization of locally available medicinal plants offer remarkable opportunity for ethnomedicinal research. The present paper aims to explore medicinal plant diversity and use in the remote villages of eastern Nepal. It also aims to evaluate ethnopharmacological significance of the documented use reports and identify species of high indigenous priority. Materials and methods The study was undertaken in four villages located in the Sankhuwasabha district in eastern Nepal. Ethnomedicinal information was collected through structured interviews. The homogeneity of informant's knowledge and the relative importance of documented medicinal plants were validated by informant consensus factor and use value, respectively. Species preference for treatment of particular diseases was evaluated through fidelity level. Results We reported medicinal properties of 48 species belonging to 33 families and 40 genera, for the treatment of 37 human ailments. The uses of 10 medicinal plants were previously undocumented. The informant consensus factor (FIC) ranged between 0.38 and 1 with about 50% of values greater than 0.80 and over 75% of values greater than 0.70, indicating moderate to high consensus among the informants on the use of medicinal plants in the region. Swertia chirayita was the most preferred species with significantly high use values, followed by Paris polyphylla and Neopicrorhiza scrophulariiflora. Conclusions The remote villages in eastern Nepal possess rich floral and cultural diversity with strong consensus among informants on utilization of plants for local healthcare. The direct pharmacological evidence for medicinal properties of most species indicates high reliability of documented information. Careful and systematic screening of compounds isolated from these plants could possibly provide good opportunity for the discovery of novel medicines to treat life-threatening human diseases. We recommend prioritization of medicinal plants and reinforcement of existing cultivation practices for sustainable management of high-priority species.

Aim: The location of zoogeographical boundaries in eastern China has long been the subject of debate. To identify any north/south genetic divergence between the Palaearctic and Sino-Japanese realms proposed by previous studies, we conducted a comparative phylogeographical study involving three passerine species with wide latitudinal distributions in eastern China. Location: Eastern China. Methods: Two mitochondrial genes and three nuclear introns were amplified and sequenced. Population structures were analysed using intra-specific phylogeny, tcs networks, AMOVA and structure inferences. We tested for evidence of genetic barriers based on pairwise differences. Lineage divergences, demographic dynamics and gene flow between lineages were estimated using Bayesian methods. Results: A congruent north/south phylogeographical divergence was identified for three species. A geographical barrier was inferred at c. 40° N in eastern China. The population sizes of the northern and southern lineages have both been stable through the late Pleistocene, while multiple divergences were inferred during the early and middle Pleistocene. Main conclusions: Our results suggest a general phylogeographical break in north-eastern China, coinciding with the Palaearctic/Sino-Japanese boundary. Physical blocking of the Yan Mountains and fragmentation of suitable habitat during glacial stages between the north and south probably acted together to provide long-lasting barrier effects. Our comparative phylogeographical approach demonstrates that the Palaearctic/Sino-Japanese boundary may represent a gene-flow barrier even within widespread species. A zoogeographical boundary between the Palaearctic and Sino-Japanese realms documented by consistent north/south phylogeographical divergences in three woodland birds in eastern China .

NCBIminer is freely available, cross-platform and user-friendly software for mining nucleotide sequence data from GenBank. It has several features that enable users to accurately and efficiently download sequences with specific attributes from the GenBank database: 1) it uses a novel search strategy, and can download sequences for distantly related taxonomic groups with high accuracy; 2) it deals with genes, CDS, rRNA, and other GenBank-defined feature types; 3) it can filter sequences by length and similarities with the reference sequence using user-defined parameters; 4) it can download information on DNA sample collections, e.g. voucher specimen, country, latitude and longitude, and collector; 5) it takes advantage of parallelization for a high efficiency workflow. We demonstrate the use and performance of NCBIminer by downloading sequences for the plant family Campanulaceaes. Compared to other methods, NCBIminer harvests more and longer sequences, and is less sensitive to query sequences.