Species In Southwest China Research Articles

Potential distributions of seven sympatric sclerophyllous oak species in Southwest China depend on climatic, non-climatic, and independent spatial drivers

•Key message An ensemble modelling approach was performed to predict the distributions of seven sympatric sclerophyllous oak species in the Hengduan Mountains of Southwest China. Spatial eigenvector filters revealed missing factors in addition to commonly used environmental variables, thus effectively improved predictive accuracy for the montane oak species. This study identified a richness center of sclerophyllous oaks, which provides a reference for proper conservation and utilization of oak resources. •Context As key species and important trees for construction- and fuel-wood, montane sclerophyllous oaks (Quercus sect. Heterobalanus) in the Hengduan Mountains of Southwest China are threatened by climate change, habitat fragmentation, and human activities. •Aims This study aims to simulate the potential distributions of seven sympatric sclerophyllous oak species with an emphasis on exploring the relative importance of climatic, non-climatic, and additional spatial factors. •Methods We performed an ensemble modelling approach of six ecological niche models in combination with spatial eigenvector filters to predict the potential distributions of seven oak species. •Results The results elucidated that temperature seasonality, followed by land use/cover and the human influence index were the most critical variables controlling oak species distributions. Regardless of the selected algorithm, the best performing models for most oaks combined climatic and non-climatic factors as well as additional spatial filters. •Conclusion It is necessary to strengthen the conservation of oak species at the junction of Sichuan and Yunnan Province where we found the richness center of the studied oaks. Our research provides essential insights for the rational conservation and management of sclerophyllous oak species, suggesting that spatial constraints might reflect limited ability of migration under future climate change.

Phylogeographic analyses of poplar revealed potential glacial refugia and allopatric divergence in southwest China

The distribution pattern and genetic structure of plant species have been profoundly influenced by climate oscillations. Phylogeographic analyses have been numerously conducted in biodiversity hotspot regions and some general conclusions have been documented. However, other regions have received less attentions and these places may serve as potential glacial refugia for plant species to survive the Quaternary glaciation. Here, we used six nuclear and three cpDNA markers to estimate the phylogeographic pattern of Populus davidiana, a widespread species distributed in southwest China. As a widely distributed species in southwest China, the nucleotide diversity of P. davidiana was relatively high (N a = 6.28, H O = 0.534, and H E = 0.658). Genetic differentiation (F ST) between the two main distribution regions, Yunnan and Guizhou provinces, was 0.21221. According to the composition of chloroplast haplotypes and the result of structure in these populations, we clearly distinguished two distantly sublineages corresponding to two distribution regions. Results of the Mantel test showed that there was a significant correlation between genetic distance and geographical distance (R 2 = 0.8252, p<.05). The topographically heterogeneous regions and the low dispersal ability of seed and pollen may lead to high genetic differentiation between these two regions. A potential glacial refugia for P. davidiana located in adjacent regions to the Hengduan range was revealed and allopatric divergence in separated glacial refugia may directly lead to the present phylogeographic pattern of this species.

基于MaxEnt模型的雅砻江冬麻豆生境适宜性评价

雅砻江冬麻豆（Salweenia bouffordiana）是近年发现的西南特有冬麻豆属新濒危种，主要分布于四川新龙县的雅砻江河谷。开展其生境适宜性评价及其影响因素分析是对其有效保护的前提和基础。基于2015年8月在雅砻江河谷调查获得的55个分布点，结合24个环境变量数据，利用最大熵模型分析影响雅砻江冬麻豆生境的主要环境因子及其适宜生境预测。结果表明：（1）AUC（曲线下面积）值高于0.9，模型具有较高的准确度，适宜于雅砻江冬麻豆的生境适宜性预测和评估；（2）年均温、最湿月降水、昼夜温差月均值和距河流距离是影响雅砻江冬麻豆生境的最主要环境变量，其最适生境环境变量组合为年均温7.9℃、最湿月降水120-124 mm、昼夜温差月均值13.8℃以及距河流距离33 m；（3）雅砻江冬麻豆的潜在适宜和次适宜生境面积分别约为4.83×10³ hm²和2.37×10⁴ hm²，但仅约7.56×10² hm²的潜在适宜生境和3.28×10³ hm²的潜在次适宜生境位于现有自然保护区管辖范围内。雅砻江冬麻豆的潜在适生区主要沿雅砻江河谷呈狭长的条带状分布，现存区受人类活动影响大，未有生物学地位定级，应尽快确定其生物学保护地位，建立保护小区或社区保护地进行就地保护。;Salweenia bouffordiana is a recently discovered endangered endemic species in southwest China, which mainly distributes along the valley of Yalong River in Xinlong County, Sichuan Province. The effective conservation of S. bouffordiana lies on evaluation of habitat suitability. The MaxEnt model is employed to identify the primary impact factors of the habitat of S. bouffordiana and to predict and evaluate its potentially suitable habitats. The analysis is based on 24 environmental variables of the area and data of field investigation along the Yalong river valley in 55 distribution points. We found that: (1) the AUC (area under ROC curve) value is over 0.9, indicating that the predictive effect of this model is appropriate, and the model can be used to predict and assess the habitat suitability of S. bouffordiana. (2) Mean annual temperature, precipitation of wettest month, mean diurnal temperature range and distance to river are the most predominant environmental variables affecting the habitat suitability of S. bouffordiana. The most suitable combination of environmental variables is a mean annual temperature of 7.9 ℃, a precipitation of wettest month of 120-124 mm, a mean diurnal temperature range of 13.8 ℃ and a distance of 33 m to river. (3) The areas of potential suitable and sub-suitable habitats for S. bouffordiana are 4.83×10³ hm² and 2.37×10⁴ hm², respectively. However, only potential suitable habitats of 7.56×10² hm² and sub-suitable habitats of 3.28×10³ hm² are within the jurisdiction of the existing nature reserves. The potential habitats are limited and mainly distributed along the valley. There are existing human activities to hamper the development and propagation of the population of S. bouffordiana in the current survival areas. In addition, the biological status of S. bouffordiana has not yet been assessed and determined. We suggest that the assessment and determination of biological status for S. bouffordiana should be put on the agenda. Small nature protected areas or community protected areas should be introduced for in-site conservation.

Climate change jointly with migration ability affect future range shifts of dominant fir species in Southwest China

AbstractAimAs a prominent geographical distribution centre for the dark coniferous forests, mountains of Southwest China (MSWC) is experiencing an unprecedented warming trend, posing severe challenges to the survival of dominant fir (Abies) species. Although plant's migration ability is a prerequisite for its survival in changing environments, it has often been ignored in species distribution models (SDMs). This study aimed to quantify the magnitude and direction of range changes by the year 2080 for six dominant fir species, that isAbies recurvata,Abies faxoniana,Abies squamata,Abies ernestii,Abies forrestiiandAbies georgei, with an emphasis on exploring the relationship between migration ability and projected distributions.LocationThe mountains of Southwest China.MethodsWe applied the Maximum Entropy (Maxent) algorithm to calibrate ecological niche models and to project the climatically suitable areas (CSAs) of each species under two emission scenarios (RCP 4.5 and RCP 8.5). Additionally, we delimited future species ranges by three migration scenarios (full‐, no‐ and partial‐migration scenarios).ResultsThe simulations showed the distinctive responses of the six fir species to anthropogenic climate change (ACC). By 2080, the distribution areas ofAbies recurvatawere projected to decline only in the no‐migration scenario but increase under the full‐ and partial‐migration scenarios, while the other five species were projected to decline in the majority of emission × migration scenarios. Fir species in the southern region were predicted to be more vulnerable to ACC due to the larger losses in CSAs and a stronger effect of the partial‐migration scenario on the newly colonized areas of this group. The studied species showed a simulated migration trend (northward and westward) to the interior Qinghai‐Tibet Plateau under ACC.Main conclusionsBenefits or losses for species under ACC depended on the geographical location, their ecological niches and migration abilities, which provide essential insights for a spatial conservation assessment of biodiversity hotspots in the future.

Expanding ensembles of species present-day and future climatic suitability to consider the limitations of species occurrence data

Abstract Outputs of species distribution models (SDMs) are widely used as indicators of climate conditions favorable for species occurrence. When using these outputs to inform planning and decision making, it is essential that the uncertainties associated with the projections of present-day and future climatic suitability are carefully considered. Climate change assessments routinely consider the uncertainty introduced into SDM outputs by differences in future climate projections, and other uncertainty sources, such as the choice of the threshold to convert simulated probabilities to binary climatically suitable areas, are also oftentimes considered. However, the uncertainty introduced by the limitations of the species occurrence data used in the SDM calibration is rarely evaluated. These limitations, which include location error, sampling bias, and species misidentification, may reduce the utility of SDM outputs in conservation research and practice. Using understory bamboo species in southwest China as examples, here we demonstrate that species occurrences obtained using remote sensing offer an additional dataset for calibrating SDMs that, in conjunction with conventional observations and employing an ensemble approach of outputs from multiple models, provide an estimate of the uncertainty introduced by the species occurrence data. A biweekly time series of the satellite-based Wide Dynamic Range Vegetation Index (WDRI) was employed to estimate bamboo occurrence based on phenological signatures of the bamboo species and their overstory canopies. Using Maxent, a popular modeling framework, present-day and projected future climatic suitability were assessed separately for conventional species presence observations from the Fourth National Giant Panda Survey and for the remotely-sensed presence estimates. The ensemble of model outputs suggests that the uncertainty introduced by the species occurrence data, along with the interaction with other sources of uncertainty, may be as substantial as the uncertainty introduced by the use of different climate scenarios or by the threshold used to estimate binary climatically suitable areas. Ignoring the uncertainty introduced by the limitations of the species occurrences may compromise the interpretation of SDM outputs and reduce their usefulness for conservation planning. Remote sensing is a largely untapped resource for assessing uncertainty in SDM simulations.

The complete chloroplast genome of Yunnanopilia longistaminea (Opiliaceae), an endemic species in southwest China

The complete chloroplast genome sequence of Yunnanopilia longistaminea, an endemic species in southwest China, is presented in this study. The total genome size of Y. longistaminea was 148,503 bp in length, with a typical quadripartite structure including a pair of inverted repeat (IRs, 28,075 bp) regions separated by a large single copy (LSC, 84,547bp) region and a small single copy (SSC, 7805 bp) region. The all GC content was 37.3%. The genome contains 117 genes, including 72 protein-coding genes, 37 tRNA genes, and 8 rRNA genes, 13 genes contain a single intron, and 3 genes have two introns. Further, a maximum-likelihood (ML) phylogenetic tree results that Y. longistaminea was closely related to the genera of Champereia manillana.

The complete chloroplast genome of Impatiens uliginosa Franch., an endemic species in Southwest China

The complete chloroplast genome sequence of Impatiens uliginosa Franch., an endemic species in Southwest China, we research genetic and phylogenetic relationship with other species in an effort to provide genomic resources useful for promoting its conservation and utilization. The total chloroplast genome size of I. uliginosa is 152,609 bp, with a typical quadripartite structure including a pair of inverted repeat (IRs, 25,871 bp) regions separated by a small single copy (SSC, 17,502 bp) region and a large single copy (LSC, 83,365 bp) region. The overall GC content of I. uliginosa plastid genome was 36.8%. The whole chloroplast genome contains 136 genes, including 89 protein-coding genes (PCGs), 38 transfer RNA genes (tRNAs), and 8 ribosomal RNA genes (rRNAs). Among these genes, 15 genes have one intron and 2 genes contain two introns. To investigate the evolution status, the phylogenetic tree based on APG III from 12 complete chloroplast plastomes of Ericales supports close relationships. According to the phylogenetic topologies, I. uliginosa was closely related to I. piufanensis.

The complete chloroplast genome of Primula tsiangii W. W. Smith (Primulaceae): a karst endemic primrose in Southwest China

Primula tsiangii W. W. Smith is a karst endemic species in Southwest China. Here, we report the complete chloroplast genome of P. tsiangii. The chloroplast (cp) genome was determined to be 153,281 bp and the GC contents was 37.2%. The sequence includes a large single copy (LSC) region of 84,524 bp, a small single copy (SSC) region of 17,357 bp, and two separated inverted regions of 25,700 bp each. It contains 127 unique genes, including 82 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. This is the first report of cp genomes for karst endemic primrose, and will be useful for the genetic diversity of karst plants.

Characterization of the chloroplast genome of Cassia siamea Lain, a rosewood species from southeast China

Cassia siamea is a rosewood species in Southwest China with high wood and medicinal value. To clarify genetic background of C. siamea, we sequenced chloroplast genome by Illumina Hiseq and PacBio Sequel. The whole genome was 148,437 bp in length, containing a large single copy region (77,723 bp), a small single copy region (18,462 bp) and a pair of inverted repeats regions (26,126 bp). The cp genome contained 102 genes (71 protein-coding genes, 27 tRNAs and 4 rRNAs). The phylogenetic analysis indicated that C. siamea is close to Senna tora within Cassiinae/Caesalpiniaceae. The complete chloroplast genome of C. siamea will provide useful resources for the development and utilization of this species and the phylogenetic study of Fabaceae.

Complete chloroplast genome of a widely distributed species in southwest China, Hemiphragma heterophyllum Wall. (Scrophulariaceae)

Hemiphragma heterophyllum Wall., a widely distributed species in southwest China, belongs to a monotypic genus, Hemiphragma Wall. in the Scrophulariaceae. To date, there has been no study on its complete chloroplast genome. Hence, we reported the first complete chloroplast genome sequence of H. heterophyllum here. The genome sequences of two individuals were extremely similar except slight differences on sequence lengths (152,707 bp and 152,700 bp, respectively). There was a typical circular quadripartite structure. A total of 113 genes were annotated, including 79 protein-coding genes, 29 tRNA genes, four rRNA genes, and one pseudogene. Among the annotated genes, 16 genes contained one intron, whereas another two genes (ycf3 and clpP) possessed two gene introns. Total GC content is 38.1% in the chloroplast genome. Moreover, a total of 63 simple sequence repeats (SSRs) with five types were detected. Phylogenetic analysis revealed that Hemiphragma was closely related to Veronica L. and Veronicastrum Heist. ex Farbic.

Physiological and Growth Responses to Increasing Drought of an Endangered Tree Species in Southwest China

Research Highlights: We compared annually resolved records of tree-ring width and stable isotope of dead and surviving Fokienia hodginsii (Dunn) Henry et Thomas trees. We provide new insights into the relationships and sensitivity of tree growth to past and current climate, and explored the underlying mechanism of drought-induced mortality in F. hodginsii. Background and Objectives: Drought-induced tree decline and mortality are increasing in many regions around the world. Despite the high number of studies that have explored drought-induced decline, species-specific responses to drought still makes it difficult to apply general responses to specific species. The endangered conifer species, Fokienia hodginsii, has experienced multiple drought-induced mortality events in recent years. Our objective was to investigate the historical and current responses to drought of this species. Materials and Methods: We used annually resolved ring-width and δ13C chronologies to investigate tree growth and stand physiological responses to climate change and elevated CO2 concentration (Ca) in both dead and living trees between 1960 and 2015. Leaf intercellular CO2 concentration (Ci), Ci/Ca and intrinsic water-use efficiency (iWUE) were derived from δ13C. Results: δ13C were positively correlated with mean vapor pressure deficit and PDSI from previous October to current May, while ring widths were more sensitive to climatic conditions from previous June to September. Moreover, the relationships between iWUE, basal area increment (BAI), and Ci/Ca changed over time. From 1960s to early 1980s, BAI and iWUE maintained a constant relationship with increasing atmospheric CO2 concentration. After the mid-1980s, we observed a decrease in tree growth, increase in the frequency of missing rings, and an unprecedented increase in sensitivity of 13C and radial growth to drought, likely related to increasingly dry conditions. Conclusions: We show that the recent increase in water stress is likely the main trigger for the unprecedented decline in radial growth and spike in mortality of F. hodginsii, which may have resulted from diminished carbon fixation and water availability. Given that the drought severity and frequency in the region is expected to increase in the future, our results call for effective mitigation strategies to maintain this endangered tree species.

Which Species Should We Focus On? Umbrella Species Assessment in Southwest China.

In conservation biology, umbrella species are often used as agents for a broader set of species, or as representatives of an ecosystem, and their conservation is expected to benefit a large number of naturally co-occurring species. Southwest China is home to not only global biodiversity hotspots, but also rapid economic and population growth and extensive changes in land use. However, because of the large regional span, the diverse species distributions, and the difficulty of field investigations, traditional methods used to assess umbrella species are not suitable for implementation in Southwest China. In the current study, we assessed 810 key protected species from seven taxa by indicator value analysis, correlation analysis, and factor analysis. We selected 32 species as umbrella species, whose habitats overlapped the habitats of 97% of the total species. Furthermore, the selected species were significantly correlated with 70% of all species in the study area. A total of 16 out of 19 selected animal species have been previously mentioned as umbrella species, compared with only 3 out of 13 plants species; this is despite plants accounting for a large proportion of the total species in Southwest China. We discuss the roles of indicator species and co-occurring species, and provide suggestions for species protection in Southwest China based on the current results. Our research provides valuable scientific information for research on umbrella conservation species over large geographical scales, and related fields of biodiversity conservation.

The complete chloroplast genome of Populus xiangchengensis, an endemic species in Southwest China

The complete chloroplast genome sequence of Populus xiangchengensis C. Wang et Tung, an endemic species in southwest China, is presented in this study. The total genome size is 156,465 bp, with a typical quadripartite structure including a pair of inverted repeat (IRs, 27,570 bp) regions separated by a large single copy (LSC, 84,812 bp) region and a small single copy (SSC, 16,513 bp) region. The overall GC content of P. xiangchengensis plastid genome is 36.74%. The genome contains 130 genes, including 85 protein-coding genes, 37 transfer RNA genes, and eight ribosomal RNA genes. Among these genes, 12 genes have one intron and three genes contain two introns. The phylogenetic tree based on 26 complete plastomes of Salicaceae support close relationships among P. xiangchengensis, P. cathayana, and P. szechuanica.

Construction of core collection of Psammosilene tunicoides based on polymorphism of β-AS gene

Psammosilene tunicoides is one of the main ingredients of the "Yunnan Baiyao". P. tunicoides is an endangered species included in the secondary protection list in China Plant Red Data Book as well as the endemic species in Southwest China. Its natural resources could not meet the needs of pharmaceutical production. Construction of core collection of P. tunicoides will lay the foundation for germplasm improvement and molecular breeding. The sequence variation of the key enzymes gene locus (β-AS) were carried out to survey the population structure and population history of the species. Among the 11 populations across its geographical range, 36 haplotypes were identified. The levels of haplotype diversity (Hd=0.905) were high, while the levels of population differentiation (GST=0.280) were low. Analysisof molecular variance (AMOVA) indicated that a significantly greater proportion of total genetic variationpartitioned among populations thanwithin populations (values of 77.43% and 22.57%, respectively). These results in combination with the star-like phylogenetic network analysis indicate that Hap1 as an ancestral haplotypewas shared in four populations, Hap2, Hap4, Hap15 and Hap16 are occurred in two populations, the remains as private haplotype only distributed in single population. The strategy of core collection was constructed in order to maximumpreserve genetic diversity of P. tunicoides.

Transcriptome analysis of Panax zingiberensis identifies genes encoding oleanolic acid glucuronosyltransferase involved in the biosynthesis of oleanane-type ginsenosides

Oleanolic acid glucuronosyltransferase (OAGT) genes synthesizing the direct precursor of oleanane-type ginsenosides were discovered. The four recombinant proteins of OAGT were able to transfer glucuronic acid at C-3 of oleanolic acid that yields oleanolic acid 3-O-β-glucuronide. Ginsenosides are the primary active components in the genus Panax, and great efforts have been made to elucidate the mechanisms underlying dammarane-type ginsenoside biosynthesis. However, there is limited information on oleanane-type ginsenosides. Here, high-performance liquid chromatography analysis demonstrated that oleanane-type ginsenosides (particularly ginsenoside Ro and chikusetsusaponin IV and IVa) are the abundant ginsenosides in Panax zingiberensis, an extremely endangered Panax species in southwest China. These ginsenosides are derived from oleanolic acid 3-O-β-glucuronide, which may be formed from oleanolic acid catalyzed by an unknown oleanolic acid glucuronosyltransferase (OAGT). Transcriptomic analysis of leaves, stems, main roots, and fibrous roots of P. zingiberensis was performed, and a total of 46,098 unigenes were obtained, including all the identified homologous genes involved in ginsenoside biosynthesis. The most upstream genes were highly expressed in the leaves, and the UDP-glucosyltransferase genes were highly expressed in the roots. This finding indicated that the precursors of ginsenosides are mainly synthesized in the leaves and transported to different parts for the formation of particular ginsenosides. For the first time, enzyme activity assay characterized four genes (three from P. zingiberensis and one from P. japonicus var. major, another Panax species with oleanane-type ginsenosides) encoding OAGT, which particularly transfer glucuronic acid at C-3 of oleanolic acid to form oleanolic acid 3-O-β-glucuronide. Taken together, our study provides valuable genetic information for P. zingiberensis and the genes responsible for synthesizing the direct precursor of oleanane-type ginsenosides.

Effects of the Tanaka Line on the genetic structure of Bombax ceiba (Malvaceae) in dry-hot valley areas of southwest China.

Southwest China is an important biodiversity hotspot. The interactions among the complex topography, climate change, and ecological factors in the dry‐hot valley areas in southwest China may have profoundly affected the genetic structure of plant species in this region. In this study, we determined the effects of the Tanaka Line on genetic variation in the wild Bombax ceiba tree in southwest China. We sampled 224 individuals from 17 populations throughout the dry‐hot valley regions. Six polymorphic expressed sequence tag–simple sequence repeat primers were employed to sequence the PCR products using the first‐generation Sanger technique. The analysis based on population genetics suggested that B. ceiba exhibited a high level of gene diversity (H E: 0.2377–0.4775; I: 0.3997–0.7848). The 17 populations were divided into two groups by cluster analysis, which corresponded to geographic characters on each side of the Tanaka Line. In addition, a Mantel test indicated that the phylogeographic structure among the populations could be fitted to the isolation‐by‐distance model (r 2 = .2553, p < .001). A barrier test indicated that there were obstacles among populations and between the two groups due to complex terrain isolation and geographic heterogeneity. We inferred that the Tanaka Line might have promoted the intraspecific phylogeographic subdivision and divergence of B. ceiba. These results provide new insights into the effects of the Tanaka Line on genetic isolation and population differentiation of plant species in southwest China.

Physiological regulation of poplar species to experimental warming differs between species with contrasting elevation ranges

Climate warming has resulted in rapid range shifts of plant species, but it is not well known how species with different natural distribution ranges adapt to increase in temperature through physiological adjustment. We experimentally imposed a 1.8 °C increase of air temperature to the cuttings of two common poplar species Populus yunnanensis and Populus szechuanica naturally growing in southwest China using open-top chambers. Populus yunnanensis is distributed along a narrower elevation range compared with P. szechuanica. We determined some key physiological parameters and plant growth regulator activities during the growing season without soil water limitation. Our results showed that a 1.8 °C increase in air temperature increased shoot growth of P. szechuanica through an extension of its growth period but did not affect the growth of P. yunnanensis. Malondialdehyde content, guaiacol peroxidase activities and abscisic acid content increased while indoleacetic acid content decreased in P. yunnanensis. Our results suggest that the two common poplar species in southwest China should be able to adapt to the moderate increase in temperature projected for future climate. The growth of P. szechuanica may benefit through phenological adjustment but a further increase in temperature may inhibit the growth of P. yunnanensis. For poplar plantation management, selecting species with a wide natural distribution range could provide an adaptive alternative for buffering anthropogenic induced increase in temperature and help in sustaining productivity for the long term.

Complete chloroplast genome of Firmiana major (Malvaceae), a critically endangered species endemic to southwest China

Firmiana major is an endangered species in southwest China, which had been considered as extinct in the wild on the IUCN Red List of Threatened Species in 1998. Fortunately, around 2000 wild individuals were rediscovered along the valley of Jinshajiang river in south Sichuan and north Yunnan. In this study, we reported a complete chloroplast genome of F. major, which was de novo assembled using the next-generation sequencing data. The plastome was 161,302 bp in length, consisting of a pair of inverted repeat (25,543 bp for each), one large single copy (90,178 bp) and one small single copy (20,038 bp) regions. The whole genome contained 132 genes, including 87 protein-coding, 37 tRNA and 8 rRNA genes. The overall GC content of the whole genome was 36.9%. Maximum likelihood analysis showed that F. major was sister to Tilia spp.

The distribution, diversity, and conservation status of Cycas in China.

As ancient gymnosperm and woody plants, cycads have survived through dramatic tectonic activities, climate fluctuation, and environmental variations making them of great significance in studying the origin and evolution of flora biodiversity. However, they are among the most threatened plant groups in the world. The principal aim of this review is to outline the distribution, diversity, and conservation status of Cycas in China and provide suggestions for conservation practices. In this review, we describe the taxonomy, distribution, and conservation status of Cycas in China. By comparing Chinese Cycas species with its relatives worldwide, we then discuss the current genetic diversity, genetic differentiation of Cycas, and try to disentangle the potential effects of Quaternary climate changes and topographical events on Cycas. We review conservation practices from both researchers and practitioners for these rare and endangered species. High genetic diversity at the species level and strong genetic differentiation within Cycas have been observed. Most Cycas species in southwest China have experienced population retreats in contrast to the coastal Cycas's expansion during the Quaternary glaciation. Additionally, human activities and habitat fragmentation have pushed these endangered taxa to the brink of extinction. Although numerous efforts have been made to mitigate threats to Cycas survival, implementation and compliance monitoring in protection zones are currently inadequate. We outline six proposals to strengthen conservation measures for Cycas in China and anticipate that these measures will provide guidelines for further research on population genetics as well as conservation biology of not only cycads but also other endangered species worldwide.

Phylogenetic analyses of Phragmites spp. in southwest China identified two lineages and their hybrids

The species/lineage delimitation and possible hybridization/introgression are prerequisites in the management of invasive organism. Phragmites australis invaded diverse habitats and displaced the native lineages in North America as a consequence of the introduction from the Eurasia. Such species threatened the biodiversity safety of the invaded regions, in particular the biodiversity hot spots. Southwest (SW) China is a biodiversity hot spot with the occurrence of Phragmites species, both native and introduced. However, the genetic identity of Phragmites species in this biodiversity hot spot remains unclear, hampering effective ecological managements. In this study, we explored the phylogenetic lineages of Phragmites species in SW China. A total of 44 accessions sampled across SW China were analyzed using two chloroplast DNA (cpDNA) markers and amplified fragment length polymorphisms. Two genetic lineages were recovered, i.e., (1) the tropical lineage which primarily consisted of native Phragmites species represented by cpDNA haplotypes I, Q, and U in relatively low altitude and (2) the common lineage including native species at higher elevations in the Hengduan Mountains as well as artificially planted species represented by cpDNA haplotype P. The between-lineage hybridization was suggested for five analyzed accessions collected from either natural or artificial habitats. The putative hybrids might have originated from the maternal native tropical lineages and paternal introduced common lineage. Our results suggest the likelihood of introgressive hybridizations in SW China and thus provided implications for future research and ecological management.