Qinling-Daba Mountains Research Articles

Phylogenetic relationships of the zokor genus <i>Eospalax</i> (Mammalia, Rodentia, Spalacidae) inferred from whole-genome analyses, with description of a new species endemic to Hengduan Mountains

Zokors in the genus Eospalax, which are endemic to northern and western China, are subterranean rodents that inhabit various niches, including grasslands, high-altitude meadows, forests, and farmlands. Six species in Eospalax were described a century ago but their taxonomy and phylogeny remain controversial. In this study, we performed high-depth whole-genome sequencing of 47 zokor samples, comprising all six previously described species. Genomic analyses revealed a reliable and robust phylogeny of Eospalax and supported the validity of the six named species. According to the inferred phylogenetic relationships, Eospalax first divergent into two clades in the early Pliocene (ca. 4.68 million years ago (Ma)), one inhabiting the high-altitude Qinghai-Xizang (Tibet) Plateau (QTP) and adjacent regions, and the another inhabiting the low-altitude Loess Plateau and Qinling-Daba Mountains. The most recent divergences occurred between E. baileyi and E. smithii and between E. rufescens and E. rothschildi in the late Pliocene (ca. 2.09 and 2.19 Ma, respectively). We also collected specimens of zokors in the southern Hengduan Mountains (Muli County, Sichuan Province), far from the known distributions of all other zokors. Morphological and molecular analyses strongly suggested that the specimens represent a new species, formally described here as Eospalax muliensis sp. nov. The new species belongs to the high-altitude clade and diverged from closely related species (ca. 4.22 Ma) shortly after the first divergence in Eospalax. Interestingly,Eospalax muliensis sp. nov. possesses more supposedly plesiomorphic characters, suggesting a possible origin of the genus in the Hengduan Mountains.

Terrain Effects on Regional Precipitation in a Warm Season over Qinling-Daba Mountains in Central China

The terrain effects of Qinling–Daba Mountains on reginal precipitation during a warm season were investigated in a two-month day-to-day experiment using the Weather Research and Forecasting (WRF) model. According to the results from the terrain sensitivity experiment with lowered mountains, Qinling–Daba Mountains have been found to have an obvious effect on both the spatial-temporal distribution and diurnal cycle of reginal precipitation from July to August in 2019, where the Qinling Mountains mainly enhanced the precipitation around 34° N, and the Daba Mountains mainly enhanced it around 32° N at the time period of early morning and midnight. Horizontal distribution of water vapor and convective available potential energy (CAPE), as well as cross section of vertical velocity of wind and potential temperature has been studied to examine the key mechanisms for these two mountains’ effect. The existence of Qinling Mountains intercepted transportation of water vapor from South to North in the lower troposphere to across 34° N and caused an obvious enhancement of CAPE in the neighborhood, while the Daba Mountains intercepted the northward water vapor transportation to across 32° N and caused an enhanced CAPE nearby. The time period of the influence is in a good accordance with the diurnal cycle. In the cross-section, the existence of Qinling Mountains and Daba Mountains are found to stimulate the upward motion and unstable environment effectively at around 34° N and 32° N, separately. As a result, the existence of the two mountains lead to a favorable environment in water vapor, thermodynamic, and dynamic conditions for this warm season precipitation.

Cryptic diversity and phylogeography of the Rhabdophis nuchalis group (Squamata: Colubridae)

Previous studies, have found that the rapid uplift of the Tibetan plateau accelerated the diversification of species. However, there are few relevant biogeographic data for the Colubridae in this region. We conducted a comprehensive study of the Rhabdophis nuchalis Group, which presently contains four nominal species, R. nuchalis, R. pentasupralabialis, R. leonardi, and R. chiwen. Building upon previous studies with specimens we have recently examined, greater interspecific and intraspecific diversity has been revealed. Here we address three questions: (1) Do the intraspecific differences represent only geographic variation within lineages, or are there cryptic species? (2) What are the interspecific relationships among members of the R. nuchalis Group? (3) What has been the biogeographic history of this species group? To resolve these questions we used four mitochondrial gene sequences and one nuclear sequence to investigate the molecular phylogenetic and geographic relationships among populations. Our molecular analysis reveals cryptic species diversity within the R. nuchalis Group, and seven clades were identified in the analysis. Ancestral area estimation suggests that the R. nuchalis Group originated in the Hengduan Mountains approximately 6.24 Mya and expanded its range northward to the Qinling-Daba Mountains. The Sichuan Basin appears to have been a barrier to migration. Species divergence seems to have been related to the rapid uplift of the Qinghai-Tibet Plateau.

Influence of Land Use Change on the Surface Albedo and Climate Change in the Qinling-Daba Mountains

Land use changes affect the surface radiative budget and energy balance by changing the surface albedo, which generates radiative forcing, impacting the regional and global climate. To estimate the effect of land use changes on the surface albedo and climate change in a mountainous area with complex terrain, we obtained MODIS data, identified the spatial–temporal characteristics of the surface albedo caused by land use changes, and then calculated the radiative forcing based on solar radiative data and the surface albedo in the Qinling-Daba mountains from 2000 to 2015. The correlation between the land use changes and the radiative forcing was analyzed to explore the climate effects caused by land use changes on a kilometer-grid scale in the Qinling-Daba mountains. Our results show that the primarily land use changes were a decrease in the cultivated land area and an increase in the construction land area, as well as other conversions between six land use types from 2000 to 2015. The land use changes led to significant changes in the surface albedo. Meanwhile, the radiative forcing caused by the land use had different magnitudes, strengths, and occurrence ranges, resulting in both warming and cooling climate change effects.

Analysis of vegetation dynamics in the Qinling-Daba Mountains region from MODIS time series data

The Qinling-Daba Mountains region (Qinba) is an important geographical transitional zone across the north and south of China. To comprehensively understand the ecological transition in the Qinba over past two decades, this study assessed and predicted the spatiotemporal variations of vegetation comparatively, using 250-m time series MODIS NDVI and EVI products. From 2000 to 2019, remarkable increases were observed both in annual and seasonal NDVI and EVI (P < 0.05), and the increasing rate of NDVI was higher than that of EVI for all temporal scales, except summer. Compared to NDVI, larger areas of no significant change were obtained in annual, autumn, and winter EVI, primarily distributed in the high-altitude regions of western Qinba. All assessed vegetation types increased significantly during past two decades except alpine vegetation and marsh, however, the seasons in which the significant increase in NDVI and EVI occurred varied for different vegetation types. Hurst exponent analysis suggested that inconsistent characteristics of vegetation dynamic trends were stronger in the future across Qinba. The area proportion of unfavorable trends, identified mainly covered with cultivated vegetation and scrub, was much larger than that of favorable trends, especially detected by EVI. Areas likely to experience vegetation variation of unfavorable and undetermined trends deserve high focus.

Content of Selenium and Other Elements, Water Quality, Health Risks and Utilization Prospect in Natural Water of Southern Qinling-Daba Mountains, Southern Shaanxi, China

Content of Selenium and Other Elements, Water Quality, Health Risks and Utilization Prospect in Natural Water of Southern Qinling-Daba Mountains, Southern Shaanxi, China

Population Demographic History of a Rare and Endangered Tree Magnolia sprengeri Pamp. in East Asia Revealed by Molecular Data and Ecological Niche Analysis

Quaternary climate and environment oscillations have profoundly shaped the population dynamic history and geographic distributions of current plants. However, how the endangered and rare tree species respond to the climatic and environmental fluctuations in the subtropical regions of China in East Asia still needs elucidation. In this study, we collected 36 natural populations of an endangered and rare tree species Magnolia sprengeri Pamp. in subtropical China to determine the demographic history, and modeled the changes of geographic distributions of this species in East Asia based on the MaxEnt ecological niche analyses. In addition, we sequenced three maternally inherited chloroplast DNA fragments (matK, trnH-psbA, and rbcL) for all the natural populations which covered the whole geographic distributions of M. sprengeri. Population genetic analysis showed that the endangered tree species have a low level of chloroplast DNA diversity. However, the genetic variation contribution within populations was greater than that among populations (FST = 0.276), which demonstrated a high level of genetic differentiation. Interestingly, some unique chloroplast DNA haplotypes and higher genetic variations were identified in the Qinling-Daba Mountains, Central China, and Tianmu Mountains of Zhejiang province, East of China in East Asia. Combining with the species distribution modeling, we speculated that these areas might be the potential glacial refugia for the endangered plant M. sprengeri. Phylogeographic analysis demonstrated that the geographic factors (e.g., mountains, rivers, and other isolation barriers) had little effect on the genetic divergence among populations. Ecological niche modeling further revealed that the natural populations of M. sprengeri did not experience significant geographic distribution changes from the last glacial maximum to the present time. These findings are in line with the analysis results of the multimodal mismatch patterns of the chloroplast DNA variations. To protect the endangered species M. sprengeri, in situ and ex situ conservation strategies should be formulated for the natural populations with higher genetic variations.

Species richness and endemism pattern of Fagaceae in Southwest China and their environmental interpretation.

How to accurately model species macro-richness patterns and endemism centers is a key focus of biodiversity conservation efforts and a hot biogeographical topic. Southwest China is one of regions with high Fagaceae species richness, the species diversity patterns and driving mechanisms are unclear. In this study, the distribution pattern of species richness (SR), weighted endemism (WE), and corrected weighted endemism (CWE) indices were estimated based on 7258 occurrence points of 161 Fagaceae species in Southwest China using both occurrence-to grid method and species distribution model (SDM). We used the spatial autoregressive (SAR) model to analyze the relationship between diversity indices and environmental factors. Overall, the three SDM-simulated diversity indices were more continuous in values than that of the occurrence-to grid method, though the distributions of those indices obtained by the two methods were similar. The areas with high SR value were mainly distributed in the south edge of Yunnan, north Guangxi and southwest Guangxi (62-89 species). The maximum of WE concentrated in south Yunnan and west Guangxi (1.77-5.02). The highest CWE (0.07-0.17) was found in southeast Tibet, Qinling-Daba Mountains, southwest Guangxi, and southeast Yunnan. The SAR models showed significant effect of precipita-tion in the driest month, standard deviations of seasonal temperature, altitude range and soil organic carbon content on SR. The effects of precipitation in the driest month, standard deviations of seaso-nal temperature, potential evaporation and altitude range on the WE were significant. The precipitation in the driest month, standard deviations of seasonal temperature, historical temperature change, coefficient of variation of enhanced vegetation index and altitude variation had significant effects on the CWE. The R2 of SAR model for SR, WE and CWE was 0.857, 0.733, 0.593, respectively, being higher than that of ordinary least squares (OLS) (R2=0.689, 0.425, 0.422). In conclusion, water availability, climate seasonality, habitat heterogeneity, historical climate change and soil condition were the most important factors limiting the distribution of SR and WE of Fagaceae in Southwest China. The SR and WE centers of Fagaceae were located in south and southeast Yunnan, southwest Guangxi, west Guangxi, Qinling-Daba Mountains, and southeast Tibet, where should be adequately protected.

North-south vegetation transition in the eastern Qinling-Daba Mountains

The Qinling-Daba Mountains are the main body of China’s North-South Transitional Zone. Analysis of the north-south gradual variation of vegetation components is significant for understanding the structural diversity and complexity of this transitional zone. In this study, based on survey data of plant communities, the eastern Qinling-Daba Mountains is divided into four geographic units: the north flank of eastern Qinling Mts., south flank of eastern Qinling Mts., north flank of eastern Daba Mts. and south flank of eastern Daba Mts. We also explore division of regional climate according to areal differentiation of plant-species, community structure and species-richness, respectively. The results show that, (1) at plant-species level, there are mainly northern plants in north flank of eastern Qinling Mts. with evergreen species and fewer northern plants in south flank of eastern Qinling Mts.; there are mainly southern plants in eastern Daba Mts. (2) At community structure level, there are 4 formations (3 northern formations and 1 widespread formation) in north flank of eastern Qinling, 6 formations (3 northern formations, 1 southern formation, and 2 widespread formations) in south flank of eastern Qinling, 4 formations (2 southern formations and 2 widespread formations) in north flank of eastern Daba Mts., and 3 formations (3 southern formations) in south flank of eastern Daba Mts. In terms of the numbers and properties of formations, there is a mixture of northern and southern formations only in the south flank of eastern Qinling Mts. (3) At species-richness level, the diversity of families, genera and species decreased with increasing latitude, but the mixing of northern plants and the southern plants began to occur in south flank of eastern Qinling Mts. This means that the south flank of the eastern Qinling Mts. serves more suitably as the dividing line between China’s warm temperate and subtropical zones.

Qualitative analysis of Gynostemma longipes for medicinal usage

The Qinling-Daba Mountains area is the main producing areas of Gynostemma longipes for medicinal usage, and samples of wild whole plants in Pingli, Shaanxi Province and Qingchuan, Sichuan Province were collected. The ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UHPLC-Q-TOF-MS~E) was used to profile the chemical compositions and analyze the similarities and differences of G. longipes samples in these areas. Based on the accurate molecular weight and fragment information obtained from Q-TOF-MS~E, the structures of the main components were identified by combining with the mass spectra, chromatographic behaviors of reference standards and related literatures. The results showed that the components of wild G. longipes from different places among Qinling-Daba Mountains area were similar. Forty-five chemical components were identified in the whole plant of G. longipes from Pingli, Shaanxi Province, including 43 triterpenoid saponins and 2 flavonoids which contain all main peaks in its fingerprint. The main components are dammarane-type triterpenoid saponins, such asgypenoside ⅩLⅨ, gypenoside A and its malonylated product of glycosyl.

Spatial Pattern and Development of Protected Areas in the North-south Transitional Zone of China

The north-south transitional zone in China mainly consists of the Qinling-Daba Mountains. It is the most important West-East geo-ecological space in China, containing protected areas vital for biodiversity conservation and ecological security of China. The protection and rational development of its natural habitat is of great significance to China’s ecological security and integration of protected areas based on mountain forest ecosystems on a global scale. In this study, five important types of protected areas in the transitional zone were selected, and their spatial patterns were analysed. Spatial analysis methods, such as kernel density estimation and accessibility analysis, were employed for both point and areal data, and focused on four aspects: land use scale, shift in the centre of gravity, spatial agglomeration, and accessibility. In addition, policy background and evolution of spatial and temporal characteristics of the protected area system in the transitional zone from 1963 to 2017 were also examined. We analysed the characteristics and geographical significance of the West-east corridor using the spatial pattern of the protected area system from the perspective of ecological and economic spaces. We focused on spatial shape, type intersection, and key areas to analyse the spatial overlap of the protected areas. Protected area establishment was divided into three stages: initial (1956–1980), rapid development (1981–2013), and national park transformation (2014—present). These stages reflected the change in the concept of ‘simple protection—sustainable use—integration and upgrade’ for protected areas of China. The spatial centre of gravity of the protection zone system was located in the west Qinling-Daba Mountains, and its high-density core exhibited a relatively stable N-shaped structure composed of four gathering areas. Affected by factors such as geographic environment and socio-economic development density, the average access time for protected areas was high (1.56 h); wetland parks and scenic areas are located closer to the city centre. As the West-east corridor in the transitional zone extends from west to east, there is a clear spatial dislocation between the development of protected areas and the intensity of human activities. During development, differentiated goal orientation should be adopted based on the idea of zoning and classified governance. With the advancement of the construction of protected areas, the spatial overlap of protected areas in the transition zone has become more prominent. At present, the spatially overlapped protected areas in the transitional zone remain prominent, with inclusion overlap being the most common, and forest parks exhibiting the highest probability of overlap with other protected areas, we should focus on in the integration process of the corridor-type ecological space based on the mountain forest ecosystem.

Spatiotemporal variations of extreme precipitation and its potential driving factors in China’s North-South Transition Zone during 1960–2017

Based on the daily data collected from 69 meteorological stations in the Qinling-Daba Mountains (Qinba mountains) and its surrounding areas during 1960–2017. We analyzed The spatiotemporal variations of extreme precipitation events in the Qinba mountains and the relationship between the changes of extreme precipitation indices and potential factors (including geographical factors and atmospheric circulation patterns). The Mann-Kendall method and linear trend analysis were used to test the variations of extreme precipitation indices. Besides, the Pearson correlation analysis method was used to analyze the correlation between precipitation extremes and potential controlling factors (including geographic and atmospheric factors). The results showed that (1) consecutive dry days (CDD), simple daily intensity index (SDII), highest 1-day precipitation (RX1day) and very heavy rain days (R20mm), very wet days (R95P) and extremely wet days (R95P) and extremely wet days (R99P) showed an increasing trend, all other extreme precipitation indices showed decreasing trend and the change trends in all extreme indices were non-significant in annual and seasonal scales over Qinba mountains; (2) extreme precipitation increased in the eastern part of Qinba mountains while decreased in the western region; (3) there is a significant correlation between altitude, longitude, latitude and extreme precipitation; (4) the large-scale atmospheric circulation patterns also a significant impact on the spatiotemporal variations of extreme precipitation in the transition areas; the change of extreme precipitation indices is closely related to the El Niño–Southern Oscillation (ENSO) at interannual scales; (5) East Asian Summer Monsoon Index (EASMI) and the South China Sea Summer Monsoon Index (SCSSMI) show significant correlation with the extreme precipitations in summer while Arctic Oscillation (AO) show significant correlation wih the extreme indices in winter in Qinba mountains. Results of this study may help to deeper understand and predict the extreme precipitation events in Qinba mountains.

秦巴山地NPP及对气候变化响应的多维地带性与暖温带-亚热带界线

秦巴山地NPP及对气候变化响应的多维地带性与暖温带-亚热带界线

Regional function transformation and high-quality development path in Qinling-Daba Mountains of Shaanxi province

Regional function transformation and high-quality development path in Qinling-Daba Mountains of Shaanxi province

Exploring on the climate regionalization of Qinling-Daba mountains based on Geodetector-SVM model.

Qinling-Daba Mountains (QDM), which are located in central China, are considered as a significant climatic boundary delimiting north and south. However, the influence of complex topographic and climatic features makes it challenging to identify the exact location of the boundary, and different scholars delimit the boundary with significant differences. In addition, there is a gradual transition between climate zones, and no real dividing line exists. To explore the climate regionalization of the QDM, we focused on the identification of the transition zone rather than the exact location of the boundary between subtropical and temperate zones. Thus, we proposed a new workflow for climate regionalization based on the Geodetector-SVM model (a combination of Geodetector and support vector machines). First, we selected the spatial distribution data of six vegetation types (including typical subtropical and temperate vegetation) to represent the spatial distribution of climatic zones. Environmental factors (such as topography, temperature, precipitation, and soil) were used as explanatory variables for the spatial distribution of vegetation. Second, using the Geodetector-SVM model, the distribution characteristics and suitable environment of typical vegetation in different climatic zones are comprehensively explored. By analyzing the multiple boundaries between subtropical and temperate vegetation, the location of the transition zone of the QDM was identified. The results revealed the following: (1) The new workflow for climate regionalization based on the Geodetector-SVM model is powerful for the identification of the transition zone. The q-statistics are generally greater than 0.35, indicating that the transition zone between subtropical and temperate zones can highly reflect the character of the QDM; (2) From west to east, the transition zone mainly passes through the cities of Heishui County, Kang County, Liuba County, and Yichuan County and is approximately 30 km wide.

Spatial patterns of Pinus tabulaeformis and Pinus massoniana forests in Qinling-Daba Mountains and the boundary of subtropical and warm temperate zones

The Qinling Mountains is not only the geographical boundary between North and South China, but also the boundary between subtropical and warm temperate zones. It plays an important role in the geo-ecological pattern of China. However, there is controversy about the specific location of this geographical boundary in academic community due to the complexity, transition and heterogeneity of the transitional zone, as well as the differences in the delimitation indicators and research purposes. To further reveal the characteristics of the North-South transitional zone and clarify the specific location of the geo-ecological boundary between North and South China, combined with SRTM topographic data, temperature and precipitation data, Pinus massoniana forest and Pinus tabulaeformis forest, which represent subtropical coniferous forest in South China and temperate coniferous forest in North China respectively, were chosen to analyze their spatial distributions in the Qinling-Daba Mountains and the climatic conditions at their boundary with the climatic indexes of annual precipitation, the coldest month (January) average temperature, the warmest month (July) average temperature and the annual average temperature. The results show that: (1) Pinus massoniana and Pinus tabulaeformis forests and the climate indicators of their boundary can be used as one of the vegetation-climate indexes for the delimitation of subtropical and warm temperate zones. The boundary between the subtropical coniferous forest (Pinus massoniana forest) and temperate coniferous forest (Pinus tabulaeformis forest) is located along the south slope of Funiu Mountain to the north edge of Hanzhong Basin (the south slope of Qinling Mountains) at an altitude of 1000–1200 m, where the climatic indictors are stable: the annual precipitation is about 750–1000 mm, the annual average temperature is about 12–14°C, the coldest monthly average temperature is 0–4°C, and the warmest monthly average temperature is about 22–26°C. (2) It can be more scientifically to delimitate the boundary of subtropical and warm temperate zones in China by comprehensively considering the vegetation-climate indicators. Additionally, the boundary between subtropical and warm temperate zones in Qinling-Daba Mountains should be a transitional zone consisting of the boundaries of coniferous forests, broad-leaved forests and shrubs between subtropical and warm temperate zones. The results provide a scientific basis for the selection of delimitation index of subtropical and warm temperate zones.

Discussion on position of China’s north-south transitional zone by comparative analysis of mountain altitudinal belts

The Qinling Mountains has always been regarded as an essential dividing line between the warm temperate zone and the subtropical zone in eastern China and plays a vital role in the geoecological pattern of China. However, there is controversy about the specific location of this geographical boundary in the academic community. As a product of the combined effects of zonal and non-zonal factors, the mountain altitudinal belts (MABs) can reflect both the horizontal zonality and the vertical zonality of vegetation distribution. Using the MAB information, we can not only profoundly understand the complex mountain system of Qinling-Daba Mountains but can also judge its nature as a geographical boundary more scientifically. Therefore, based on the comparative analysis of basal belt, dominant belt characteristics and belt structure characteristics of the MABs in Qinling-Daba Mountains, subtropical and temperate mountains, this paper analyzed the MAB differences and similarities among Qinling-Daba Mountains, subtropical and temperate typical mountains, to reveal the vegetation distribution characteristics in the north-south transitional zone. The results show that: (1) The MABs of the southern part of Qinling-Daba Mountains (southern slope of the Daba Mountains) are the same or similar to those of the Subtropical Mountains, and the MABs of the northern part of Qinling-Daba Mountains (northern slope of the Qinling Mountains) are similar to those of the temperate mountains. While it shows obvious transitional characteristics in the vast area between the northern slope of the Daba Mountains and the southern slope of the Qinling Mountains: the basal belts gradually transit from the evergreen broad-leaved forest belt (basal belt in subtropical mountains) to the evergreen and deciduous broad-leaved mixed forest belt, and the dominant belts also transit from the evergreen broad-leaved forest belt to the evergreen and deciduous broad-leaved mixed forest belt or the deciduous broad-leaved forest belt. (2) The transitional zone between the subtropical zone and the warm temperate zone is located between the northern slope of the Daba Mountains and the southern slope of the Qinling Mountains. The southern boundary of the transitional zone is along the northern slope of Shennongjia Mountain-the northern slope of Micang Mountain-Baishuijiang Nature Reserve, and the northern boundary is along the southern slope of Funiu Mountain-the southern slope of Taibai Mountain-Lianhua Mountain. Additionally, in the transitional zone, the average temperature in January is between -5°C and 1°C, the annual average temperature is between 10°C and 13°C except Hanzhong Basin and Hanshui Valley, and the accumulated temperature above 10°C ranges from 2000°C to 4000°C, the annual rainfall is about 800–1000 mm. The results provide a scientific basis for revealing the characteristics of China’s north-south transitional zone and scientific division of the boundary between the subtropical zone and warm temperate zone in China.

Spatial variation of altitudinal belts as dividing index between warm temperate and subtropical zones in the Qinling-Daba Mountains

To determine the dividing index between warm temperate and subtropical zones based on the spectra of altitudinal belts, this paper collected 33 spectra of altitudinal belts in the Qinling-Daba Mountains from published literatures and then analyzed the structures and the spatial patterns from south to north, from west to east and based on exposure directions. The results show that: 1) From south to north, the basal belt gradually changes from subtropical evergreen broadleaf forest to warm temperate deciduous broadleaf forest; the spectra of altitudinal belts change from complex to simple; the dominant belt changes from montane broadleaf-conifer mixed forest and evergreen-deciduous broadleaf mixed forest to deciduous broadleaf forest. 2) From west to east, the structures of the altitudinal belt spectra show complexity in the east and west but simplicity in the middle section; the upper limits of both the evergreen-deciduous broadleaf mixed forest belt and montane deciduous broadleaf forest belt present a quadratic curve distribution pattern in the longitudinal direction. However, the upper limit of the montane broadleaf-conifer mixed forest belt exhibits a nearly linear decrease in the west-east direction. 3) Both the north and south slopes in the Qinling Mountains have the similar basal belt, whereas it varies greatly between the north and south slopes in the Daba Mountains. Comparably, dominant belts are very similar in the Qinling Mountains and the north slope of the Daba Mountains, but the south slope of the Daba Mountains has its own unique dominant belt: evergreen-deciduous broadleaf mixed forest. This implies that the Daba Mountains are more appropriate than the Qinling Mountains to act as the boundary between subtropical and warm-temperate zones in central China.

Economic efficiency of farmer participation in tourism-led village poverty alleviation：A case study of key poverty-stricken villages in the Qinling-Daba Mountains

Economic efficiency of farmer participation in tourism-led village poverty alleviation：A case study of key poverty-stricken villages in the Qinling-Daba Mountains

Responses of potential suitable area of Paris verticillata to climate change and its dominant climate factors

Prediction of the potential distribution of species based on the data of its current distribution in combination with climatic variables is important for understanding species evolution and reasonable conservation. Based on 220 distribution sites in China and 12 low-correlation climatic variables, we analyzed the potential distribution of Paris verticillata at present and future (2050s and 2070s) using the MaxEnt model and ArcGIS program. Further, we analyzed the dominant driving factors for its geographic distribution. The results showed that the area under the curve indices (AUC) was 0.940, with high prediction accuracy. The potential suitable regions of P. verticillata were mainly distributed in the Greater Xing'an Mountains, the Xiao Xing'an Mountains, the Changbai Mountains, the Qinling-Daba Mountains, Hebei, Shanxi and north Shandong under current climate scenario. Those regions accounted for 18.1% of the total suitable area in the country, of which the highly suitable areas accounted for 7.0% and the lowly suitable area 11.1%. The total suitable areas of P. verticillata in the 2050s and 2070s would decline under the climate change scenarios of RCP 2.6, RCP 4.5, RCP 6.0 and RCP 8.5. The highly suitable area would decline, but the lowly suitable area would increase. With the global climate change, both the range and the geometric center of its distribution would gradually spread to higher altitude in the northeast. The cumulative contributions of four dominant factors reached as high as 89.2%, namely, precipitation of wettest month, mean annual temperature, isothermality, and precipitation of January. Their appropriate ranges were 100-275 mm, -0.1-16 ℃, 21-35 and 3-14 mm, respectively.