Search Results (40)

With the global economic restructuring and the consequent population mobility, urban shrinkage has become a common phenomenon. The Qinling–Daba Mountains, a zone with a key ecological function in China, have long experienced population decline and functional degradation. Clarifying the dynamics and influencing factors of urban shrinkage plays a vital role in supporting the sustainable development of the region. This study, using permanent resident population growth rates and nighttime light data, classified cities in the region into four spatial patterns: expansion–growth, intensive growth, expansion–shrinkage, and intensive shrinkage. It further examined the spatial characteristics of shrinkage across four periods (2005–2010, 2010–2015, 2015–2020, and 2020–2022). A Geographically and Temporally Weighted Regression (GTWR) model was applied to examine core influencing factors and their spatiotemporal heterogeneity. The results indicated the following: (1) The dominant pattern of urban shrinkage in the Qinling–Daba Mountains shifted from expansion–growth to expansion–shrinkage, highlighting the paradox of population decline alongside continued spatial expansion. (2) Three critical indicators significantly influenced urban shrinkage: the number of students enrolled in general secondary schools (X₅), the per capita disposable income of urban residents (X₇), and the number of commercial and residential service facilities (X₁₂), with their effects exhibiting significant spatiotemporal heterogeneity. Temporally, X₁₂ was the most influential factor in 2005 and 2010, while in 2015, 2020, and 2022, X₅ and X₇ became the dominant factors. Spatially, X₇ significantly affected both eastern and western areas; X₅’s influence was most pronounced in the west; and X₁₂ had the greatest impact in the east. This study explored the patterns and underlying drivers of urban shrinkage in underdeveloped areas, aiming to inform sustainable development practices in regions facing comparable challenges. Full article

Traditional villages are irreplaceable cultural heritages, embodying complex human–environment interactions. This study uses historical geography analysis, kernel density estimation, centroid migration modeling, and Geodetector techniques to analyze the 2000-year spatiotemporal evolution and formation mechanisms of 224 nationally designated traditional villages in China’s Qinling-Daba Mountains. The findings are as follows: (1) These villages significantly cluster on sunny slopes of hills and low mountains with moderate gradients. They are also closely located near waterways, ancient roads, and historic cities. (2) From the embryonic stage during the Qin and Han dynasties, through the diffusion and transformation phases in the Wei, Jin, Song, and Yuan dynasties, to the mature stage in the Ming and Qing dynasties, the spatial center of these villages shifted distinctly southwestward. This migration was accompanied by expansion along waterway transport corridors, an enlarged spatial scope, and a decrease in directional concentration. (3) The driving forces evolved from a strong coupling between natural conditions and infrastructure in the early stage to human-dominated adaptation in the later stage. Agricultural innovations, such as terraced fields, and sociopolitical factors, like migration policies, overcame environmental constraints through the synergistic effects of cultural and economic networks. Full article

Rhododendron purdomii Rehder & E. H. Wilson (Ericaceae) is a threatened ornamental and medicinal shrub or small tree species primarily distributed in the Qinling-Daba Mountains of Central China. To facilitate its conservation and utilization, the complete chloroplast genome of Rh. purdomii was sequenced, assembled, and characterized. The cp genome exhibited a typical quadripartite structure with a total length of 208,062 bp, comprising a large single copy (LSC) region of 110,618 bp, a small single copy (SSC) region of 2606 bp, and two inverted repeat (IR) regions of 47,419 bp each. The overall GC content was 35.81%. The genome contained 146 genes, including 96 protein-coding genes, 42 transfer RNA genes, and 8 ribosomal RNA genes. Structure analysis identified 67,354 codons, 96 long repetitive sequences, and 171 simple sequence repeats. Comparative genomic analysis across Rhododendron species revealed hypervariable coding regions (accD, rps9) and non-coding regions (trnK-UUU-ycf3, trnI-CAU-rpoB, trnT-GGU-accD, rpoA-psbL, rpl20-trnC-GCA, trnI-CAU-rrn16, and trnI-CAU-rps16), which may serve as potential molecular markers for genetic identification. Phylogenetic reconstruction confirmed the monophyly of Rhododendron species and highlighted a close relationship between Rh. purdomii and Rh. henanense subsp. lingbaoense. These results provide essential genomic resources for advancing taxonomic, evolutionary, conservation, and breeding studies of Rh. purdomii and other species within the genus Rhododendron. Full article

The multifunctionality of green infrastructure (GI) can be enhanced through intentional planning that promotes synergies among various functions while minimizing trade-offs. Despite its significance, methodologies for implementing this approach remain underexplored. This paper presents an application-oriented framework for GI planning that emphasizes the relationship between GI functional performance and the provision of ecosystem services. By reframing the issues of multifunctional synergies and trade-offs as quantifiable and spatially explicit problems associated with ecosystem services, the framework offers both a conceptual foundation and technical protocols for practical application. This framework was implemented in the Qinling–Daba Mountain Area (QDMB) in China to evaluate its practicality and identify potential challenges. The planned GI system aims to fulfill multiple functions, including biodiversity maintenance, water and soil conservation, eco-farming, and ecotourism development. Additionally, 73 wildlife corridors were established to connect GI elements, thereby enhancing habitat services for biodiversity. Furthermore, the analysis identified 245 townships and 273 sites as strategic areas and points requiring targeted intervention to mitigate potential multifunctional trade-offs. These locations are characterized by their location within protected areas, protected buffer zones, or wildlife corridors, or at the intersection of wildlife corridors with existing transportation infrastructure. The findings validate the framework’s practicality and highlight the necessity for additional research into the capacity of GI to support diverse human activities and the approaches to enhance GI elements’ connectivity for multifunctionality. Full article

The complexity of forest ecosystems leads to differences in the distribution patterns of different vegetation types along elevation gradients. This study aimed to explore the characteristics of AGB variations along elevation gradients for different forest types and tree species components in the Qinling–Daba Mountains. Based on 329 field vegetation survey plots, including four sampling transects and four representative mountains, individual tree AGB was calculated using allometric biomass equations. Further, generalized additive models (GAMs) were used to investigate the relationships between AGB and elevation for four forest types (broadleaf forests, coniferous forests, mixed coniferousbroadleaf forests, and shrublands) and three AGB components (total AGB (tAGB), broadleaf species AGB (bAGB), and coniferous species AGB (cAGB)) across eight vegetation survey regions. The results showed that the AGB of different forest types is significantly related to elevation (p < 0.05), with broadleaf forest AGB showing a unimodal pattern with elevation, coniferous forest and mixed forest AGB increasing with elevation, and shrubland AGB exhibiting a noticeable rise at higher elevations. The AGB components across different vegetation survey regions also showed significant relationships with elevation (p < 0.05), with broadleaf species AGB displaying a monotonically increasing trend in regions with a small elevation range and exhibiting a unimodal or bimodal distribution in regions with a large elevation range, while coniferous species AGB generally increased with elevation. Although elevation significantly influenced forest AGB, the variation in R² values indicated that elevation is not the sole determinant of AGB variation. This study improves the understanding of spatial patterns of forest biomass along elevation gradients. Full article

Understanding ecological niche evolution patterns is crucial for elucidating biogeographic history and guiding biodiversity conservation. Taxus is a Tertiary relict gymnosperm with 11 lineages mainly distributed across East Asia, spanning from tropical to subarctic regions. However, the spatiotemporal dynamics of its ecological niche evolution and the roles of ecological and geographical factors in lineage diversification, remain unclear. Using occurrence records, environmental data, and reconstructed phylogenies, we employed ensemble ecological niche models (eENMs), environmental principle components analysis (PCA-env), and phyloclimatic modeling to analyze niche similarity and evolution among 11 Taxus lineages. Based on reconstructed Bayesian trees and geographical distribution characteristics, we classified the eleven lineages into four clades: Northern (T. cuspidata), Central (T. chinensis, T. qinlingensis, and the Emei type), Western (T. wallichiana, T. florinii, and T. contorta), and Southern (T. calcicola, T. phytonii, T. mairei, and the Huangshan type). Orogenic activities and climate changes in the Tibetan Plateau since the Late Miocene likely facilitated the local adaptation of ancestral populations in Central China, the Hengduan Mountains, and the Yunnan–Guizhou Plateau, driving their expansion and diversification towards the west and south. Key environmental variables, including extreme temperature, temperature and precipitation variability, light, and altitude, were identified as major drivers of current niche divergence. Both niche conservatism and divergence were observed, with early conservatism followed by recent divergence. The Southern clade exhibits high heat and moisture tolerance, suggesting an adaptive shift, while the Central and Western clades retain ancestral drought and cold tolerance, displaying significant phylogenetic niche conservatism (PNC). We recommend prioritizing the conservation of T. qinlingensis, which exhibits the highest PNC level, particularly in the Qinling, Daba, and Taihang Mountains, which are highly degraded and vulnerable to future climate fluctuations. Full article

Oaks in the genus Quercus L. are keystone species in the forest ecosystem and are considered ideal models for the study of plant evolution. In this research, we applied population genetics, ecological niche analysis and phenotypic traits to explore patterns of species differentiation and demographic history of two Chinese montane oak species (Quercus baronii Skan and Quercus dolicholepis A. Camus) from Quercus section Ilex across species distribution ranges. Analyses of population genetics with ten nuclear microsatellite loci on 33 populations of the two oak species indicated great interspecific genetic variations with distinct genetic backgrounds for the two oaks. Simulations on species demography suggested a speciation-without-migration model as the best to explain species divergence, while an approximate Bayesian computation analysis indicated that the two studied oak species probably split at about 17.80–28.48 Ma. A comparison of two core bioclimatic factors and ecological niche tests revealed strong niche differentiation between the two oak species, and association analysis also found a significantly positive correlation between interspecific genetic variations and bioclimatic distances. Additionally, analyses of the leaf morphology of 117 specimens with five quantitative characteristics showed clear species discrepancy between Q. baronii and Q. dolicholepis. Based on this evidence from genetic, ecological and phenotypic analyses, our research indicated clear species differentiation between Q. baronii and Q. dolicholepis, possibly in relation to an early species divergence and varying adaptative features of the two oaks shaped by heterogeneous environments within Qinling-Daba Mountains and surroundings. This study provides an example for future investigation of species differentiation and evolution among related oak species with integrated analyses and highlights the importance of ecological conditions on adaptive evolution and genetic conservation of endemic tree species in montane regions. Full article

Acer griseum (Franch.) Pax is an endangered species endemic to China, mainly scattered in the Qinling–Daba Mountains. The genetic diversity of 17 natural populations were analyzed by nuclear DNA (nDNA) and chloroplast DNA (cpDNA) to explore the driving forces for its microevolution. A high level of genetic diversity (nDNA: He = 0.296, cpDNA: Ht = 0.806) was found in A. griseum. Genetic variation was mainly within populations (92.52%) based on nDNA, while it was mainly among populations (96.26%) based on cpDNA. The seventeen populations were divided into two groups, corresponding to the subtropical zone (Group I) and temperate zone (Group II), with haplotype 4 (Hap4) and Hap5 being the most common haplotypes, respectively. Consequently, genes associated with heat and heavy metal stress were identified in Group I, while genes related to salt and drought stress were identified in Group II. Haplotype differentiation was driven by the heterogeneous microenvironment caused by the uplifting of the Qinling-Daba Mountains, which was a vital source of its high genetic diversity. Furthermore, the uplifted Qinling–Daba mountains may bridge high pollen flow among populations, whereas rivers can result in low seed flow among populations, which has led to the incongruent genetic structure between nDNA and cpDNA. This study represents a new perspective that geological events, especially orogeny, play an important role in plant microevolution through the establishment of maternal genetic structure and provides a meaningful conservation strategy for A. griseum. Overall, the Qinling–Daba Mountains not only are cradles for the genetic diversity of A. griseum but also provided refugia for it during the Quaternary glacial period. Full article

Human activities, especially industrial production and urbanization, have significantly affected vegetation cover, water resource cycles, climate change, and biodiversity in the Qinling-Daba Mountain region and its surrounding areas. These activities contribute to complex and lasting impacts on ecological vulnerability. The Qinling Mountain region exhibits a complex interaction with human activities. The current research on the ecological vulnerability of the Qinling Mountain region primarily focuses on spatial distribution and the driving factors. This study innovatively applies the VSD assessment and Bayesian networks to systematically evaluate and simulate the ecological vulnerability of the study area over the past 20 years, which indicates that the integration of the VSD model with the Bayesian network model enables the simulation of dynamic relationships and interactions among various factors within the study areas, providing a more accurate assessment and prediction of ecosystem responses to diverse changes from a dynamic perspective. The key findings are as follows. (1) Areas of potential and slight vulnerability are concentrated in the Qinling-Daba mountainous regions. Over the past 20 years, areas of extreme and high vulnerability have significantly decreased, while areas of potential vulnerability and slight vulnerability have increased. (2) The key factors impacting ecological vulnerability during this period included industrial water use, SO₂ emissions, industrial wastewater, and ecological water use. (3) Areas primarily hindering the transition to potential vulnerability are concentrated in well-developed small urban regions within basins. Furthermore, natural factors like altitude and temperature, which cannot be artificially regulated, are the major impediments to future ecological restoration. Therefore, this paper recommends natural restoration strategies based on environmental protection and governance strategies that prioritize green development as complementary measures. The discoveries of the paper provide a novel analytical method for the study of ecological vulnerability in mountainous areas, offering valuable insights for enhancing the accuracy of ecological risk prediction, fostering the integration of interdisciplinary research, and optimizing environmental governance and protection strategies. Full article

When focusing on biodiversity maintenance, ecological security pattern (ESP) planning gradually becomes a multi-objective planning strategy for sustainable development; wildlife conservation and ecosystem health maintenance should be balanced with local economic development and people’s livelihood enhancement goals. This study focuses on ESP mapping in the Qinling-Daba Mountain area, which is an ecologically significant and socioeconomically underdeveloped area. The tradeoff between conservation and development is made by varying the area of ecological sources and incorporating ecosystem service tradeoffs into ecological source identification through multi-scenario designation. ESPs under six scenarios were generated based on the minimum resistance model, and the important ecological corridors and strategic points in each scenario were identified and compared. The results show the following: (1) The scenario that sets around 30 percent of the study area as ecological sources maintains the integrity of natural ecosystems and leaves space for food and material supply to residents. (2) In this scenario, the ecological sources are connected by 60 corridors that cross 137 townships with high population densities (>100 people/km²) and intersect with major traffic lines at 71 points. Engineering, management, or education strategies must be taken in these townships or intersections to avoid human–wildlife conflicts. (3) The study area needs to construct both short (north–south) corridors linking proximate ecological sources for species’ daily movement and long (west–east) corridors connecting large and distant sources for species’ seasonal migration and gene flow. (4) The multi-scenario approach turns out to be an effective strategy for ESP planning with considerations for development–conservation tradeoffs. Full article

The vertical transition zone of mountain vegetation is characterized by high species diversity, and the width of the transition zone may serve as an indirect indicator of climate change. However, research into the differential characteristics of vegetation response to climate changes at the boundary of vertical transition zones has been limited. This study employs MODIS and climate data spanning 2001 to 2018 to investigate spatiotemporal trends in precipitation (PRE), temperature (TMP), radiation (RAD), and Normalized Difference Vegetation Index (NDVI) across nine montane deciduous broad-leaved forests in the eastern monsoon region of China. It explores the time-lag and -accumulation effects of climatic variables on NDVI, quantifying their relative contributions to both its short-term and interannual variations. Results show that, notably, with the Qinling-Daba Mountains as a demarcation, northern regions exhibit significant increases in RAD (0.874–2.047 W m⁻²/a), whereas southern regions demonstrate notable rises in TMP (0.59–0.73 °C/10a). Areas of lower annual PRE correspond to the most rapid increases in annual average NDVI (5.045 × 10⁻³/a). NDVI’s lag time and cumulative duration responses to TMP are the shortest (0 and 2~4 periods), while its correlation with RAD is the strongest (0.815–0.975), generally decreasing from higher to lower latitudes. TMP significantly affects NDVI variations, impacting both short-term and interannual trends, with PRE driving short-term fluctuations and RAD dictating long-term shifts. This research provides critical data and a theoretical framework that enhances our understanding of how regional vegetation’s vertical zonation responds to climate change, thereby making a substantial contribution to the study of mountain vegetation’s diverse adaptability to climatic variations. Full article

With the development of satellite remote sensing technology, a substantial quantity of remote sensing data can be obtained every day, but the ability to extract information from these data remains poor, especially regarding intelligent extraction models for vegetation information in mountainous areas. Because the features of remote sensing images (such as spectral, textural and geometric features) change with changes in illumination, viewing angle, scale and spectrum, it is difficult for a remote sensing intelligent interpretation model with a single data source as input to meet the requirements of engineering or large-scale vegetation information extraction and updating. The effective use multi-source, multi-resolution and multi-type data for remote sensing classification is still a challenge. The objective of this study is to develop a highly intelligent and generalizable classification model of mountain vegetation utilizing multi-source remote sensing data to achieve accurate vegetation extraction. Therefore, a multi-channel semantic segmentation model based on deep learning, FCN-ResNet, is proposed to integrate the features and textures of multi-source, multi-resolution and multi-temporal remote sensing data, thereby enhancing the differentiation of different mountain vegetation types by capturing their characteristics and dynamic changes. In addition, several sets of ablation experiments are designed to investigate the effectiveness of the model. The method is validated on Mt. Taibai (part of the Qinling-Daba Mountains), and the pixel accuracy (PA) of vegetation classification reaches 85.8%. The results show that the proposed multi-channel semantic segmentation model can effectively discriminate different vegetation types and has good intelligence and generalization ability in different mountainous areas with similar vegetation distributions. The multi-channel semantic segmentation model can be used for the rapid updating of vegetation type maps in mountainous areas. Full article

Due to the complex terrain and intense tectonic activity, and harsh climate in the Qinling-Daba Mountains, many landslides occur in the area. Most of these landslides are extremely active, posing a serious threat to the safety and property of local residents. As a mature deformation-monitoring technology, InSAR has been widely used in landslide detection, but the steep terrain and dense vegetation in the Qinling-Daba Mountains make detection challenging. Hence, it is important to choose suitable data sources and methods for landslide detection via InSAR in this area. This study was the first to collect ALOS/PALSAR−2 and Sentinel−1A images to detect landslides in the Qinling-Daba Mountains, applying a method combining IPTA and SBAS. In total, 88 landslides were detected and validated. The results show that the deformation-detection error rate of Sentinel−1A is 2% higher than that of ALOS/PALSAR−2 and that its landslide-recognition rate is 47.7% lower than that of ALOS/PALSAR−2. Upon comparing and analyzing the visibility, coherence, closed−loop residuals, and typical time series of landslide deformation from the two kinds of data, it was found that the extremely low quality of available Sentinel−1 A summer data is a major factor influencing that system’s performance. ALOS/PALSAR−2 is more likely to detect landslides in areas with high vegetation coverage, meeting more than 90% of the monitoring needs. It is thus highly suitable for landslide detection in the Qinling–Daba Mountains, where seasonality is significant. In this paper, for the first time, multiple data sources are compared in detail with regard to their utility in landslide detection in the Qinling–Daba Mountains. A large number of accuracy metrics are applied, and the results are analyzed. The study provides important scientific support for the selection of data sources for future landslide monitoring in the Qinling–Daba Mountain area and similar areas and for the selection of methods to evaluate the accuracy of InSAR monitoring. Full article

The hydrological response to climate change and human activities plays a pivotal role in the field of water resource management within a given basin. This study was conducted with a primary focus on the Du River basin, aiming to assess and quantify the impacts of climate change and human activities on changes in runoff patterns. The study utilized the Budyko framework in conjunction with the Soil and Water Assessment Tool (SWAT) model to project future changes in runoff while also employing statistical tests like the Pettitt and Mann–Kendall tests to identify abrupt shifts and monotonic trends in the data. The results shows that (1) The analysis of runoff data spanning from 1960 to 2016 revealed a significant declining trend (p < 0.05) in annual runoff, with an abrupt change point identified in 1994. The multi-year average runoff depth was determined to be 495 mm. (2) According to the Budyko framework, human activities were found to be the dominant driver behind runoff changes, contributing significantly at 74.42%, with precipitation changes contributing 24.81%. (3) The results obtained through the SWAT model simulation indicate that human activities accounted for 61.76% of the observed runoff changes, whereas climate change played a significant but slightly smaller role, contributing 38.24% to these changes. (4) With constant climate conditions considered, the study predicted that runoff will continue to decrease from 2017 to 2030 due to the influence of ongoing and future human activities. However, this downward trend was found to be statistically insignificant (p > 0.1). These findings provide valuable insights into the quantitative contributions of climate change and human activities to runoff changes in the Du River basin. This information is crucial for decision-makers and water resource managers, as it equips them with the necessary knowledge to develop effective and sustainable strategies for water resource management within this basin. Full article

Balsaminaceae are world-famous ornamental flowers because of their high species diversity, rich variation, peculiar flower patterns, and long ornamental cycles. To study the species diversity, distribution patterns, and distribution hotspots of Balsaminaceae in China, we updated the list of Balsaminaceae by systematically searching the related literature. The distribution pattern and hotspots of Impatiens spp. were analyzed using the ArcGIS 10.8.2 software. Combining 19 meteorological factors and one elevation factor, the Maxent model was applied to analyze the dominant environmental factors that govern the distribution of Impatiens spp. As of February 2023, Balsaminaceae in China included 360 taxa in two genera, including one taxon in the genus of Hydrocera, 359 taxa in the genus Impatiens, 271 national endemic species, and 157 provincial endemic species. Impatiens spp. showed a diffusion pattern from the tropical and subtropical regions to the high-latitude and high-elevation regions concentrated in Southwest China, especially in the Hengduan Mountains in the broad sense, Southern Tibet, the Yunnan–Guizhou–Guangxi karst region, the Qinling–Daba Mountains, and the southeastern hills. The highest species richness was found in the 1200~1500 m elevation range, with 164 species of Impatiens spp. This high species richness was maintained at between 900 and 2700 m, the elevation range where Impatiens spp. are concentrated. When 100% of the species were screened out, 110 hotspots were found, including Southeast Yunnan, Northwest Yunnan, Southern Tibet, and Western Sichuan, where most of the hotspots were concentrated and overlapped with global biodiversity centers, but other hotspots were more scattered. Annual precipitation, the minimal temperature of the coldest month, the altitude and temperature annual range, and four environmental variables with a cumulative contribution of 93.7% were the dominant environmental factors affecting the distribution of Impatiens spp. in China. This study lays the foundation for subsequent studies of Balsaminaceae diversity and is conducive to the development and use of Impatiens spp. resources. Full article