Mountains Of China Research Articles

Analysis on the shadow price of carbon emissions from China's forestry fruit industry-taking peaches as an example.

The shadow price of carbon emissions can measure the marginal output effect under the carbon emission regulation and is also one of the key indicators to construct a low-carbon development path for production units. Currently, international research on shadow price is focused on the industrial and energy sectors. However, in the context of carbon peaking and carbon neutrality targets in China, the use of shadow price to study the cost of reducing emissions from agricultural production, especially forestry fruit industries, is significant. In this paper, we use a parametric approach to construct the quadratic ambient directional distance function. Using the input-output data of peach, we then calculate the environmental technical efficiency and shadow price of carbon emissions from peach production in Guangxi, Jiangsu, Shandong, and Sichuan provinces, and further estimate the values of green output in each province. The results show that (i) the environmental technology efficiency of peach production in Jiangsu province, located in the coastal plain area of eastern China, is the highest among the four provinces, while that in Guangxi province, located in the hilly area of southeast China, is the lowest. (ii) Guangxi province has the smallest carbon shadow price of peach production among the four provinces, while Sichuan province, located in the mountainous area of southwest China, has the largest. (iii) The green output value of the peach production in Jiangsu province is the highest among the four provinces, and that in Guangxi province is the lowest. In order to effectively reduce carbon emissions in peach production without affecting economic benefits, the paper puts forward the following suggestions: for peach-producing areas in the southeast hills of China, it is necessary to increase the application of green environmental technology while reducing the input of production factors in peach production. For peach-producing areas in the northern plains of China, the input of production factors should be reduced. It is not easy for peach-producing areas in the southwest mountains of China to reduce the input of production factors while increasing the application of green technologies. Finally, for peach-producing areas in China's eastern coastal plain, the implementation of environmental regulations for peach production should be gradual.

Elevational Patterns of Tree Species Richness and Forest Biomass on Two Subtropical Mountains in China

Increasing evidence shows that both abiotic and biotic factors affect species richness and stand biomass in forests, yet the relative and interactive impacts of these factors remain debated in different forest ecosystems. We sampled 55 forest plots (600 m2 per plot) on two subtropical mountains with distinct diversity levels in China to explore the elevational patterns of tree species richness and stand biomass and examined how they were affected by climate, stand structure, and dominance of mycorrhizal types. The tree species richness of both mountains decreased with elevation, while the stand biomass exhibited unimodal or no apparent trends. On both mountains, the tree species richness was strongly shaped by climatic factors, especially the mean annual temperature, whereas the stand biomass was mainly affected by the stand structure. Specifically, on the mountain with higher species richness, both the tree height variation and maximum tree size were strongly correlated with the stand biomass. Meanwhile, on the species-poor mountain with higher elevations, only the maximum tree size correlated with the stand biomass. The dominance of ectomycorrhizal trees also had positive effects on the stand biomass of both mountains. These results suggest that climate, stand structure, and mycorrhizal dominance may jointly drive the decoupling between tree species richness and stand biomass, which should be given more attention in further research and forest management to achieve the climate change mitigation goals.

Identifying Potential Landslides in Steep Mountainous Areas Based on Improved Seasonal Interferometry Stacking-InSAR

Landslides are a major concern in the mountainous regions of southwest China, leading to significant loss of life and property damage. Therefore, it is crucial to identify potential landslides for early warning and mitigation. stacking-InSAR, a technique used for landslide identification in a wide area, has been found to be faster than conventional time-series InSAR. However, the dense vegetation in southwest China mountains has an adverse impact on the coherence of stacking-InSAR, resulting in more noise and inaccuracies in landslide identification. To address this problem, this paper proposes an improved seasonal interferometry stacking-InSAR method. It uses Sentinel-1 satellite data from 2017 to 2022. The study area is the river valley section of the G213 road from Wenchuan County to Mao County. The study reveals the characteristics of seasonal decoherence in the steep mountainous region, and identifies a total of 21 potential landslides using the improved method. Additionally, optical satellite imagery and LiDAR data were used to assist in the identification of potential landslides. The results of the conventional stacking-InSAR method and the improved seasonal interferometry stacking-InSAR method are compared, showing that the latter is more effective in noise suppression caused by low coherence. Their standard deviations were reduced by 46%, 22%, 10%, and 14%, respectively, using the quantitative statistics for the four tested areas. The proposed method provides an efficient and effective approach for detecting potential landslides in the mountainous regions of southwest China. It can serve as a valuable technical reference for future landslide identification studies in this area.

Molecular phylogeny, historical biogeography, and classification of Pseudocoladenia butterflies (Lepidoptera: Hesperiidae)

The range of the butterfly genus Pseudocoladenia includes several biodiversity hotspots, such as the Himalayas, mountains of southwestern China, and Sundaland. However, the taxonomic status of some of its species/subspecies remain controversial, and no previous phylogenetic or biogeographic analyses have been conducted. Herein, we determined the systematic relationships and biogeographic history of this genus by reconstructing its phylogeny based on six genes and 69 specimens as representatives of all known species/subspecies. Two species delimitation methods (Bayes Poisson Tree Processes and Bayesian Phylogenetics and Phylogeography) were also employed to assess the status of each taxon. Based on these results and morphological evidence, we identified 12 species and three subspecies in the genus and subsequently classified these into three species groups: P. fatih, P. dea, and P. dan. Five taxa, P. sadakoe (Sonan and Mitono, 1936) stat. nov., P. celebica (Fruhstorfer, 1909) stat. nov., P. fulvescens (Elwes and Edwarda, 1897) stat. nov., P. eacus (Latreille, 1823) stat. nov., and P. fabia (Evans, 1949) stat. nov. were all recognized as independent species. Additionally, two taxa, P. eacus sumatrana (Fruhstorfer, 1909) comb. nov. and P. eacus dhyana (Fruhstorfer, 1909) comb. nov., were placed under P. eacus (Latreille, 1823) stat. nov. as subspecies. Another new species distributed in N. Yunnan, Pseudocoladenia yunnana Fan, Cao & Hou sp. nov., was discovered and described. Divergence time and ancestral range estimation indicated that the most recent common ancestor of Pseudocoladenia was distributed in the Himalayas-Hengduan Mountain region and Indochina and diverged approximately 14.00 Ma. Continuous and episodic dispersal, vicariance, and extinction were used to determine the current geographic distribution of the genus. The P. fatih group had a prominently disjunct distribution between the Himalaya-Hengduan Mountain and Taiwan. Meanwhile, the P. dan group was first derived in Indochina and subsequently dispersed into the southeastern Asian archipelagoes. This study provides a reference for the evolutionary route of transoceanic distributed species in Asia and elaborates on the causes of biodiversity.

Formation and distribution of landslides controlled by thrust-strike-slip fault zones and fluvial erosion in the Western Qinling Mountains, China

In active orogenic belts, fault zones and fluvial erosion are the two principal factors that control the development of landslides. The Langma-Baiya fault zone (LBFZ) and the Bailongjiang fault zone (BFZ) in the Western Qinling Mountains (WQM) in China are part of an intracontinental orogenic zone, where landslides are the principal geomorphological process. It is also one of the regions with the most severe landslide disasters in China. We established a historical landslide database for the LBFZ and BFZ, based on high-precision remote sensing image interpretation and field investigation. The results indicated a total of 2764 landslides, including 1190 large landslides and 79 giant landslides. The quality of the landslide database was evaluated using the frequency-area curve distribution characteristics, and the results showed that the small-medium size landslides are underrepresented in the database, likely due to the influence of factors such as surface erosion, vegetation coverage, and human activities. Therefore, we focused on the spatial distribution and formation mechanism of large and giant landslides. Landslides are unevenly distributed in space; specifically, our field investigation and statistical analysis of swath profiles revealed that landslides are aggregated within tectonic zones, in areas of weak rock masses, and on the banks of rivers. Finally, based on the combination of the various factors controlling landslides, we divided the study area into three subregions, for which conceptual models were established. These models highlight the importance of the distance of the fault zone to a river, together with the degree of fluvial erosion, in controlling the development of landslides. The combined effects of fluvial erosion, geological structures, and the low-grade metamorphic rocks exposed along fault zones are major controls on the development of large landslides, and the local structural characteristics of thrust-strike-slip fault zones control the type of landslides.

2.5D magnetization vector inversion of vector magnetic data

The remanent magnetization vector records the earth’s magnetic field at the time of the formation process of magnetized geologic units. Recovering the magnetization vector from magnetic data can provide extra information regarding the source properties to differentiate geologic units and reveal thermal evolution or tectonic history. To provide this information, the magnetization vector inversion (MVI) method has been used to invert for the magnetization vector. The MVI usually works with the total-field magnetic anomaly magnitude ([Formula: see text]). The magnitude is an approximation of the projection of the magnetic anomaly vector onto the normal geomagnetic field. For highly magnetic sources, the approximation error of [Formula: see text] cannot be ignored. However, this approximation error can be avoided by using measured vector magnetic data. To reduce the severe ambiguity of 3D MVI, specific constraints based on extra prior information are usually used. For 2D or 2.5D cases, MVI only inverts for magnitude and inclination of the magnetization, which encounters less ambiguity than that of the 3D case. We have developed a 2.5D MVI approach using vector magnetic data. To reduce the divergent and smooth trends in magnetization vectors recovered by MVI in the Cartesian framework, we make use of a focusing constraint method to improve the imaging. The inversion results of synthetic data indicate that the method is able to recover magnetization magnitude and inclinations close to the true values and is fairly robust to inappropriate choice of the profile location and heading. Finally, the method is applied to the measured airborne vector magnetic data from the Qixin area of the East Tianshan Mountains in China. The distributions and directions of magnetization of the mafic-ultramafic rocks and linear structures are revealed, which provides the information for distinguishing geologic units and geologic differentiation.

Failure Mechanism of Anti-Dip Layered Soft Rock Slope under Rainfall and Excavation Conditions

The phenomenon of toppling deformation and failure is common in slopes with anti-dip structures, especially in soft metamorphic rock slopes. This paper aims to explore the instability mechanism of anti-dip layered soft metamorphic rock landslides. Taking the slope of a mining area in the southern Qinling Mountains of China as a geological prototype, a large-scale centrifuge model test and a numerical simulation based on the combined finite and discrete element method (FDEM) were performed. The deformation and failure process, failure mode, and failure path of the slope under rainfall and excavation conditions were simulated. The results show that both the physical centrifuge model test and the new numerical model test can simulate the instability process of anti-dip layered soft metamorphic rock slopes, and the phenomena simulated by the two methods are also very close. Rainfall mainly weakens the mechanical properties of rock, while the excavation at the slope toe mainly changes the stress field distribution and provides space for slope deformation, both of which accelerate the instability of the anti-dip soft metamorphic rock slope. The failure process of an anti-dip layered soft rock slope can be described as follows: bending of the rock layer–tensile fracture along the layer–flexural toppling and cracking perpendicular to the rock layer–extension and penetration of the tensile fracture surface–sliding and instability of the slope.

Dicranum hengduanensis (Dicranaceae, Bryophyta), a new species with fragile leaves from the Hengduan Mountains in China

Dicranum is one of the most diverse and widespread genera within the Dicranaceae. Species diversity and distribution in this genus, however, remain not well known. During our recent expeditions to the Hengduan Mountains in China, we found an interesting moss referrable to Dicranum species that is characterized by the stiff and fragile leaves, bistratose alar cells, and by the costal cross-section in the lower portion without stereid bands with one layer of cells above and below guide cells. Morphological and molecular-phylogenetic analyses based on five chloroplast markers (rpoB, rps4-trnT, rps19-rpl2, trnH-psbA, and trnL-trnF) and one nuclear marker (ITS region) suggest that this unknown moss represents a new species here described as D. hengduanensis. The plastome of this new species presented in this study is the first complete plastome of Dicranum.

Temporal Variations in the Gut Microbiota of the Globally Endangered Sichuan Partridge (Arborophila rufipectus): Implications for Adaptation to Seasonal Dietary Change and Conservation.

Host-associated microbiotas are known to influence host health by aiding digestion, metabolism, nutrition, physiology, immune function, and pathogen resistance. Although an increasing number of studies have investigated the avian microbiome, there is a lack of research on the gut microbiotas of wild birds, especially endangered pheasants. Owing to the difficulty of characterizing the dynamics of dietary composition, especially in omnivores, how the gut microbiotas of birds respond to seasonal dietary changes remains poorly understood. The Sichuan partridge (Arborophila rufipectus) is an endangered pheasant species with a small population endemic to the mountains of southwest China. Here, 16S rRNA sequencing and Tax4Fun were used to characterize and compare community structure and functions of the gut microbiota in the Sichuan partridges across three critical periods of their annual life cycle (breeding, postbreeding wandering, and overwintering). We found that the microbial communities were dominated by Firmicutes, Proteobacteria, Actinobacteria, and Cyanobacteria throughout the year. Diversity of the gut microbiotas was highest during postbreeding wandering and lowest during the overwintering periods. Seasonal dietary changes and reassembly of the gut microbial community occurred consistently. Composition, diversity, and functions of the gut microbiota exhibited diet-associated variations, which might facilitate host adaptation to diverse diets in response to environmental shifts. Moreover, 28 potential pathogenic genera were detected, and their composition differed significantly between the three periods. Investigation of the wild bird gut microbiota dynamics has enhanced our understanding of diet-microbiota associations over the annual life cycle of birds, aiding in the integrative conservation of this endangered bird. IMPORTANCE Characterizing the gut microbiotas of wild birds across seasons will shed light on their annual life cycle. Due to sampling difficulties and the lack of detailed dietary information, studies on how the gut microbiota adapts to seasonal dietary changes of wild birds are scarce. Based on more detailed dietary composition, we found a seasonal reshaping pattern of the gut microbiota of Sichuan partridges corresponding to their seasonal dietary changes. The variation in diet and gut microbiota potentially facilitated the diversity of dietary niches of this endangered pheasant, revealing a seasonal diet-microbiota association across the three periods of the annual cycle. In addition, identifying a variety of potentially pathogenic bacterial genera aids in managing the health and improving survival of Sichuan partridges. Incorporation of microbiome research in the conservation of endangered species contributes to our comprehensive understanding the diet-host-microbiota relationship in wild birds and refinement of conservation practices.

Characterization of the complete chloroplast genome of Gypsophila huashanensis Y. W. Tsui & D. Q. Lu, an endemic herb species in China

Gypsophila huashanensis Y. W. Tsui & D. Q. Lu (Caryophyllaceae) is an endemic herb species to the Qinling Mountains in China. In this study, we characterized its whole plastid genome using the Illumina sequencing platform. The complete plastid genome of G. huashanensis is 152,457 bp in length, including a large single-copy DNA region of 83,476 bp, a small single-copy DNA region of 17,345 bp, and a pair of inverted repeat DNA sequences of 25,818 bp. The genome contains 130 genes comprising 85 protein-coding genes, 37 tRNA genes, and eight rRNA genes. Evolutionary analysis showed that the non-coding regions of Caryophyllaceae exhibit a higher level of divergence than the exon regions. Gene site selection analysis suggested that 11 coding protein genes (accD, atpF, ndhA, ndhB, petB, petD, rpoCl, rpoC2, rps16, ycfl, and ycf2) have some sites under protein sequence evolution. Phylogenetic analysis showed that G. huashanensis is most closely related to the congeneric species G. oldhamiana. These results are very useful for studying phylogenetic evolution and species divergence in the family Caryophyllaceae.

Metagenomic analysis of the relationship between the microorganisms and the volatiles' development in the wines during spontaneous fermentation from the eastern foothills of the Ningxia Helan mountains in China.

The natural fermentation of multispecies microbial communities is responsible for unique flavors of winery regions of the eastern foothills of the Ningxia Helan Mountains in China. However, the participation of different microorganisms in the metabolic network for the development of important flavor substances is not clearly defined. Microbial population and diversity on different fermentation phases of Ningxia wine were analyzed by metagenomic sequencing approach. Gas chromatography-mass spectrometry and ion chromatography were used to identify flavor components, and 13 esters, 13 alcohols, nine aldehydes and seven ketones were detected in volatile substances with odor activity values > 1, and eight organic acids were detected as important flavor components in young wine. Thus, 52 238 predicted protein-coding genes from 24 genera were identified in the Kyoto Encyclopedia of Genes and Genomes level 2 pathways of global and overview maps, and the genes were primarily involved in amino acid metabolism and carbohydrate metabolism. Major microbial genera (Saccharomyces, Tatumella, Hanseniaspora, Lactobacillus, and Lachancea) were closely related to self-characteristic compound metabolism and further contributed to wine flavor. This study clarifies the different metabolic roles of microorganisms in flavor formation during Ningxia wine spontaneous fermentation. Saccharomyces, dominant fungi involved in glycolysis and pyruvate metabolism, produces not only ethanol but also two important precursors, pyruvate and acetyl-CoA, which are necessary for the tricarboxylic acid cycle, fatty acid metabolism, amino acid metabolism, and flavor formation. Lactobacillus and Lachancea, dominant bacteria involved in lactic acid metabolism. Tatumella, dominant bacteria involved in amino acid metabolism, fatty acid metabolism, and acetic acid metabolism to produce esters in the Shizuishan City region samples. These findings provide insights into the use of local functional strains to generate unique flavor formation, as well as improved stability and quality, in wine production. © 2023 Society of Chemical Industry.

Topographic Gradient Differentiation and Ecological Function Zoning Based on Ecosystem Services: A Case Study of Fuping County

Scientifically delineating ecological function zones is essential for national territory spatial planning and comprehensive management. In this study, we evaluated five ecosystem services, habitat quality, water yield, carbon sequestration, soil conservation, and food production, in Fuping County, China, and introduced the application of the topographic position index in exploring the topographic gradient effect of each service. We next applied the K-means clustering algorithm to identify the ecosystem services bundles and analyze the dominant type of ecosystem service in these bundles. A particle swarm optimization-support vector machine model was also constructed to identify the boundaries of ecological function zones and complete the ecological function zoning. The results are as follows: (1) In Fuping County, the high-value areas of habitat quality are distributed in the west, north, and southeast; those of soil conservation are in the northwest, northeast, and southwest; those of water yield are in the east and south; those of carbon sequestration are in the west, and those of food production is in the east. (2) The habitat quality first decreases and then increases with an increasing topographic gradient; food production and water yield decline with increasing topographic gradient; carbon sequestration and soil conservation increase with increasing topographic gradient. (3) Four types of ecosystem services bundles were identified. The dominant ecosystem functions of Type I, II, and III bundles are food production and water yield, carbon sequestration, and soil conservation, respectively. Type IV bundles generally have low levels of ecosystem services in the study area. (4) Four ecological function zones were delineated: food production zone, ecological conservation zone, potential restoration zone, and critical restoration zone. The research findings can provide a theoretical and practical basis for formulating and implementing ecological spatial management policies in the Taihang Mountains of China.

Climate drivers of seed rain phenology of subtropical forest communities along an elevational gradient.

Seed rain phenology (the start and end date of seed rain) is an essential component of plant phenology, critical for understanding population regeneration and community dynamics. However, intra- and inter-annual changes of seed rain phenology along environmental gradients have rarely been studied and the responses of seed rain phenology to climate variations are unclear. We monitored seed rain phenology of four forest communities in four years at different elevations (900m, 1450m, 1650m, 1900m a.s.l.) of a subtropical mountain in Central China. We analyzed the spatiotemporal patterns of seed rain phenology of 29 common woody plant species (total observed species in the seed rain), and related the phenological variations to seed number and climatic variables using mixed-effect models with the correlation matrix of phylogeny. We found that changes in the period length were mainly driven by the end rather than the start date. The end date and the period length of seed rain were significantly different between the mast and non-mast seeding years, while no significant elevation-related trend was detected in seed rain phenology variation. Seed number, mean temperature in spring (Tspr), and winter (Twin), summer precipitation (Psum) had significant effects on seed rain phenology. When Tspr increased, the start date of seed rain advanced, while the end date was delayed and the seed rain period length was mainly prolonged by a higher seed number, Twin and Psum. Forest canopy might have a buffering effect on understory climatic conditions, especially in precipitation that lead to difference in seed rain phenology between canopy and shrub species. Our novel evidence of seed rain phenology can improve prediction of community regeneration dynamics in responding to climate changes.

Reproductive Biology and Breeding Systems of Two Opisthopappus Endemic and Endangered Species on the Taihang Mountains.

Opisthopappus is a perennial, endemic herb of the Taihang Mountains in China. Two species of this genus (O. longilobus and O. taihangensis) are important wild genetic resources for Asteraceae; however, their reproductive biology has been lacking until now. This study is the first detailed report on the reproductive biology and breeding systems of two Opisthopappus species. Through field observations, the floral syndromes of O. longilobus and O. taihangensis were found to possess a similar pattern, although O. taihangensis has a relatively larger capitulum, more ray ligules, and disc florets. The flowers of both O. longilobus and O. taihangensis are protandrous, a character that can prevent autogamy at the single-flower level, and insects are required for pollination. Further, brightly ligules, brightly bisexual florets, unique fragrance, and amount of nectar suggest that these species propagate via an entomophilous pollination system. Hymenopteran and Diptera species were observed as the effective pollinators for these two species. The outcrossing index, pollen/ovule ratio and the results of hand pollination indicated that these Opisthopappus species might have a mixed mating system that combines cross-fertilization and partial self-fertilization for O. longilobus and O. taihangensis, outcrossing predominated in the breeding system, while self-pollination played an important role in seed production when insect pollination was unavailable, particularly in a harsh environment, such as the Taihang Mountains cliffs. Meanwhile, O. taihangensis might better adapt to severe surroundings with relatively complex floral syndromes, specifically through the attraction of visiting insects and a high seed set rate. The above results not only provide reference information toward a better understanding of the survival strategies of O. longilobus and O. taihangensis in the Taihang Mountains but also lay a solid foundation for further exploring the molecular mechanisms that underly their adaptation under cliff environments.

Plutonium isotopes in the Qinling Mountains of China

Plutonium isotopes in the Qinling Mountains of China

Unearthing the importance of soil development in total phosphorus distribution in China’s mountains

Phosphorus (P) as an essential limiting nutrient for primary productivity has a far-reaching impact on ecosystem carbon sequestration. Increasing studies have evaluated the distribution and stock of soil P in natural terrestrial ecosystems, yet few studies explore the large-scale P distribution from the perspective of soil development in the mountain regions. In this study, 1254 soil samples, including organic soils (O horizon), surface mineral soils (A horizon) and parent materials (C horizon), were collected from twenty-nine mountains in China according to soil development conditions. The concentration and stock of total P in the soils were analyzed to decipher the effects of soil development along with other potential drivers on the P distribution. The results showed that total P concentration decreased significantly in the order of O horizon > A horizon > C horizon, whereas total P stock displayed an opposite trend. Spatially, soil total P concentration increased from South to North China and from West to East China, irrespective of soil horizons, whereas total P stock did not present a consistent spatial trend across the soil horizons. Climate, vegetation and atmospheric active nitrogen deposition exhibited negative effects on soil P distribution directly or indirectly by affecting pedogenesis, while soil organic carbon, pH and iron had distinctly positive effects on the P accumulation in specific horizon. The results highlight the importance of soil development on soil total P distribution in mountains, and this process should be considered when evaluating soil P dynamics in the P biogeochemical cycling models.

Elevational shift in seed plant distributions in China's mountains over the last 70 years

AbstractAimSignificant changes in species elevational ranges in mountains have been repeatedly documented, yet the direction, magnitude and drivers of these shifts remain controversial. Presently, there is still lacking evidence about the general nature of species elevational range shifts in eastern Eurasia in response to anthropogenic climate change. By using historical specimen records and recent field observations for 735 seed plant species across 29 China's mountains, we assessed changes in species' elevational centroids and their drivers.LocationChina.Time Period1950–2018.Major Taxa StudiedSeed plant species.MethodsThe elevation records of all sampled occurrences in each mountain during the two time periods were estimated, and the null models were developed to test the sampling bias. Ecological niche models (ENMs) were used to evaluate the relative importance of climate factors in constraining each species distribution. Generalized linear models (GLMs) to test the relationships between the centroid elevational range shifts of species and different divers.ResultsWe found that 54% of the species shifting upward and 46% downhill. However, species' elevational shifts significantly differed among species and mountains. Herbaceous and lowland species moved upward faster than woody and high‐elevation species. Species in temperate mountains and in mountains with taller elevational gradients moved upward, while species in subtropical mountains and in mountains with shorter elevational gradients moved downward. Precipitation changes experienced by species, species' climatic adaptations, several species' functional traits and mountain size all contributed to explain the magnitude of species' centroid elevational range shifts.Main ConclusionsOur results highlight complex biodiversity redistribution of seed plants across Chinese mountains, not necessarily conforming to the trend of species upward shifts in elevation. Changes in precipitation regimes may blur the simplistic assumption of isotherm tracking. This study fills an important geographic shortfall for our understanding of biodiversity redistribution under anthropogenic climate change.

Four new species of Viola (Violaceae) from southern China

Four new Viola species from southern China, i.e. Viola qingruii, V. heyuanensis, V. chaozhouensis, and V. longissima, are described and illustrated based on morphology and molecular phylogeny. Viola qingruii is widely distributed in the coastal mountains of southeastern China, while V. heyuanensis, V. chaozhouensis, and V. longissima, are all narrow endemics in Guangdong Province, China. These species are described and compared with the morphologically related species V. lucens, V. tenuis, V. guangzhouensis and V. huizhouensis. Phylogenetic analysis based on ITS confirmed that all of the four new species belong to Viola sect. Plagiostigma subsect. Diffusae. An identifcation key is provided to distinguish the four new species from other species of V. subsect. Diffusae in southern China. In addition, the origin and evolution of characters such as aerial stems, stolons, elaiosomes and tuberculate seeds in Viola are briefly discussed.

The past, present, and future of ecogeographic isolation between closely related Aquilegia plants.

Quantifying the strength of the ecogeographic barrier is an important aspect of plant speciation research, and serves as a practical step to understanding the evolutionary trajectory of plants under climate change. Here, we quantified the extent of ecogeographic isolation in four closely related Aquilegia species that radiated in the Mountains of SW China and adjacent regions, often lacking intrinsic barriers. We used environmental niche models to predict past, present, and future species potential distributions and compared them to determine the degree of overlap and ecogeographic isolation. Our investigation found significant ecological differentiation in all studied species pairs except A. kansuensis and A. ecalacarata. The current strengths of ecogeographic isolation are above 0.5 in most cases. Compared with current climates, most species had an expanding range in the Last Glacial Maximum, the Mid Holocene, and under four future climate scenarios. Our results suggested that ecogeographic isolation contributes to the diversification and maintenance of Aquilegia species in the Mountains of northern and SW China and would act as an essential reproductive barrier in the future.

变间距式马铃薯输送分级装置设计与试验

This paper proposed a technical idea of joint operation of conveying and grading and developed a potato conveying and grading device with variable space to realize efficient grading in the field because of the difficulties of field grading in the process of potato harvesting in the hilly mountains of northwest China. Based on field measurement of potato size distribution, the clearance between rotating plates of potato conveying and grading device was determined. The key structural parameters of the rotating plate were obtained by referring to the structure and relevant parameters of the conveying and grading device. Moreover, the conveyor chain elevation angle of the conveying and grading device was determined through the dynamics analysis of potatoes on the conveying and grading device. The inclined plane test determined the inclination angle of the potato guide plate. To reduce the damage to potatoes in the process of conveying and grading, damage analysis was carried out. Finally, Field tests were conducted with conveyor chain elevation angle, unit forward speed, and the conveyor chain line speed as test factors, and the grading accuracy and the damage rate of the potato conveying and grading device as test indexes. The test results showed that when the conveyor chain elevation angle, unit forward speed, and conveyor chain line speed were 21.0°, 0.8 m/s, and 1.3 m/s, respectively, the grading accuracy was 91.4% and the rate of potato damage was 0.88%. The operational performance of the prototype was stable, and all the test evaluation indicators could meet the agronomic requirements of the potato harvester.