Search Results (79)

As China’s first systematic assessment of high-risk Amaranthaceae invaders, this study addresses a critical knowledge gap identified in the National Invasive Species Inventory, in which four invasive Amaranthaceae species (Dysphania ambrosioides, Celosia argentea, Amaranthus palmeri, and Amaranthus spinosus) are prioritized due to CNY 2.6 billion annual ecosystem damages in China. By coupling multi-species comparative analysis with a parameter-optimized Maximum Entropy (MaxEnt) model integrating climate, soil, and topographical variables in China under Shared Socioeconomic Pathways (SSP) 126/245/585 scenarios, we reveal divergent expansion mechanisms (e.g., 247 km faster northward shift in A. palmeri than D. ambrosioides) that redefine invasion corridors in the North China Plain. Under current conditions, the suitable habitats of these species span from 92° E to 129° E and 18° N to 49° N, with high-risk zones concentrated in central and southern China, including the Yunnan–Guizhou–Sichuan region and the North China Plain. Temperature variables (Bio: Bioclimatic Variables; Bio6, Bio11) were the primary contributors based on permutation importance (e.g., Bio11 explained 56.4% for C. argentea), while altitude (e.g., 27.3% for A. palmeri) and UV-B (e.g., 16.2% for A. palmeri) exerted lower influence. Model validation confirmed high accuracy (mean area under the curve (AUC) > 0.86 and true skill statistic (TSS) > 0.6). By the 2090s, all species showed net habitat expansion overall, although D. ambrosioides exhibited net total contractions during mid-century under the SSP126/245 scenarios, C. argentea experienced reduced total suitability during the 2050s–2070s despite high-suitability growth, and A. palmeri and A. spinosus expanded significantly in both total and highly suitable habitat. All species shifted their distribution centroids northward, aligning with warming trends. Overall, these findings highlight the critical role of temperature in driving range dynamics and underscore the need for latitude-specific monitoring strategies to mitigate invasion risks, providing a scientific basis for adaptive management under global climate change. Full article

Southwest China, with typical karst, is one of the 36 biodiversity hotspots in the world, facing extreme ecological fragility due to thin soils, limited water retention, and high bedrock exposure. This fragility intensifies under climate change and human pressures, threatening regional sustainable development. Ecological strategic areas (ESAs) are critical safeguards for ecosystem resilience, yet their spatiotemporal dynamics and driving mechanisms remain poorly quantified. To address this gap, this study constructed a multidimensional ecological health assessment framework (pattern integrity–process efficiency–function diversity). By integrating Sen’s slope, a correlated Mann–Kendall (CMK) test, the Hurst index, and fuzzy C-means clustering, we systematically evaluated ecological health trends and identified ESA differentiation patterns for 2000–2024. Orthogonal partial least squares structural equation modeling (OPLS-SEM) quantified driving factor intensities and pathways. The results revealed that ecological health improved overall but exhibited significant spatial disparity: persistently high in southern Guangdong and most of Yunnan, and persistently low in the Sichuan Basin and eastern Hubei, with 41.47% of counties showing declining/slightly declining trends. ESAs were concentrated in the southwest/southeast, whereas high-EHI ESAs increased while low-EHI ESAs declined. Additionally, the natural environmental and human interference impacts decreased, while unique geographic factors (notably the rock exposure rate, with persistently significant negative effects) increased. This long-term, multidimensional assessment provides a scientific foundation for targeted conservation and sustainable development strategies in fragile karst ecosystems. Full article

Data-driven distributed hydrological models utilizing atmospheric assimilation are crucial for simulating hydrological processes, particularly in regions lacking historical observational data, and for managing and developing local water resources due to the impacts of climate change and human activities. The southern part of Yunnan is located at the southwestern border of China, and the small number of observation stations poses a major obstacle to local water-resource management and hydrological research. This paper carries out an evaluation of the accuracy of the China Atmospheric-Assimilation Dataset (CMADS) in southern Yunnan and uses CMADS data and measured data to drive the BTOPMC model to investigate hydrological processes in the Jinping River basin, a representative local sub-basin. The study shows that the probability density function statistic (SS) between CMADS data and the measured precipitation data is 0.941, and their probability density curves of precipitation are basically the same. The relative error of daily precipitation is −19%, with 90% of the daily precipitation error concentrated within ±10 mm/day, which increases as daily precipitation increases. This paper examines three precipitation scenarios to drive the hydrological model, resulting in Nash–Sutcliffe efficiency (NSE) coefficients of 66.8%, 81.0%, and 83.9% for calibration, and 54.5%, 70.2%, and 74.5% for validation. These results indicate that CMADS data possesses a certain degree of applicable accuracy in southern Yunnan. Furthermore, the CMADS-driven BTOPMC model is suitable for simulating hydrological processes and conducting water-resource research in the region. The integration of CMADS data with actual measurement data can enhance the accuracy of hydrological simulations. Overall, the CMADS data have good applicability in southern Yunnan, and the CMADS-driven BTOPMC model can be used for hydrological modeling studies and water-resource management applications in southern Yunnan. Full article

As China’s urban–rural integration progresses, the connections between urban and rural areas continue to strengthen, making the spatial matching between transportation infrastructure and tourism resources increasingly crucial for coordinated regional development. This study investigates the spatial–temporal mismatch between transportation development and tourism spatial vitality in Yunnan Province, proposing optimization strategies to improve their coordination. Using Weibo check-in big data and OpenStreetMap transportation network data, we apply Convolutional Long Short-Term Memory (ConvLSTM) networks and bivariate spatial autocorrelation analysis to examine this relationship. The results show strong transportation–tourism matching in Kunming and surrounding areas. However, northwest and southern Yunnan exhibit significant mismatches—despite transportation improvements, underdeveloped tourism resources constrain vitality growth. Particularly in some remote regions, well-developed transportation infrastructure coexists with low tourism vitality, revealing persistent spatial mismatches between transport facilities and tourism resources. In general, transportation infrastructure development generally enhances tourism spatial vitality, but requires coordinated tourism resource development and market demand alignment. The study results provide a basis for improving the coordinated development of transportation and tourism, offering practical guidance for policymakers to promote balanced regional development and urban–rural integration. 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

Gamasid mites (Acari: Mesostigmata) are ecologically diverse arthropods, many of which act as vectors for zoonotic diseases such as rickettsial pox and hemorrhagic fever with renal syndrome. This study investigates the faunal and ecological patterns of gamasid mites across five zoogeographic microregions in Yunnan Province, China, a biodiversity hotspot with complex topography. From 1990 to 2022, 18,063 small mammal hosts (primarily rodents) were surveyed, yielding 167 mite species (141,501 specimens). The key findings include the following: (1) Low host specificity: most mite species parasitized >10 host species, with Laelaps nuttalli, L. echidninus, Dipolaelaps anourosorecis, L. guizhouensis, L. turkestanicus, and L. chini dominating (>76.59% abundance). (2) Environmental heterogeneity: mountainous and outdoor habitats exhibited higher mite diversity than flatland/indoor environments. (3) Zoonotic risks: thirteen vector species with low host specificity were identified, potentially amplifying disease transmission. (4) Ecological niche dynamics: high niche overlaps (e.g., Laelaps guizhouensis vs. L. xingyiensis: O_ik = 0.997) and positive interspecific correlations (e.g., L. echidninus vs. L. nuttalli: R = 0.97, p < 0.01) suggest co-occurrence trends on shared hosts. (5) Biogeographic patterns: mite communities were clustered distinctly by microregion, with the highest similarity being obtained between western/southern plateaus (IV and V) and unique diversity in the Hengduan Mountains (I). (6) Chao 1 estimation predicted 203 total mite species in Yunnan, 36 of which were undetected in the current sampling. These results highlight the interplay of biogeography, host ecology, and environmental factors in shaping mite distributions, with implications for zoonotic disease surveillance in biodiverse regions. Full article

Sugarcane is an important economic crop in China, and its yield is significantly affected by climate change. With climate change leading to significant shifts in environmental conditions, the suitable cultivation zones for the crop are expected to change, impacting China’s sugarcane production and industry layout. This study aims to analyze potential distribution areas for sugarcane under different climate change scenarios, providing scientific guidance for optimizing future cultivation zones and resource allocation. Data on sugarcane distribution in China and 38 related environmental factors were collected. After excluding variables with high correlations, the MaxEnt model and ArcGIS 10.2 software were used to analyze the main environmental factors affecting crop survival based on contribution rates and the Jackknife method. The study simulated the suitable areas in China during the historical period and predicted future suitable areas under three greenhouse gas emission scenarios (SSP1-2.6, SSP2-4.5, and SSP5-8.5). The results showed that the Area Under the Receiver Operating Characteristic Curve (AUC) was 0.921, indicating high accuracy in the model’s analysis of suitability zones. The three dominant environmental variables influencing sugarcane distribution in China were identified as annual precipitation, min temperature of the coldest month and elevation. The primary suitable zones are concentrated in southern China, forming a “V” shape, including regions such as Guangxi, Sichuan, Guizhou, Yunnan, Hainan, and Fujian. In the future, the area of unsuitable zones is expected to decrease. The overall suitable zones for sugarcane are projected to shift towards the central and northern parts of China. This research can assist China’s sugarcane industry in addressing the challenges of climate change and provide references for its cultivation, industry layout optimization, and the selection of new planting sites. Full article

Climate change and human interference are major drivers of biodiversity loss, with profound implications for species distribution and ecosystem integrity. Among the most vulnerable groups, primates are particularly sensitive to climate change due to their specialized habitat requirements and reliance on stable environmental conditions. This study investigates the impact of climate change and human disturbance on the distribution patterns and ecological corridors of the Gaoligong hoolock gibbons (Hoolock tianxing) in Western Yunnan Province, China. Climatic variables, including elevation, temperature range, seasonality, and annual precipitation, were found to significantly influence the spatial distribution of suitable habitats for the species. Under current climatic conditions, the suitable habitat area was 9801.59 km². However, future climate scenarios projected substantial reductions in habitat area, with the RCP2.6 scenario showing a decrease of 10.07%, and the RCP4.5 and RCP8.5 scenarios resulting in reductions of 29.75% and 69.02%, respectively. Spatially, Tengchong and Longyang supported the largest habitat areas, but these regions faced significant reductions under all future scenarios, while Longchuan and Fugong exhibited minimal to no suitable habitat, especially under higher-emissions scenarios. Furthermore, our analysis revealed that future climate change would cause a shift in habitat suitability toward higher elevations, with mid- and high-elevation areas becoming increasingly important. Ecological corridors, primarily located in the southern regions, showed a trend of fragmentation, with decreasing connectivity and increasing dispersal resistance across all future scenarios. By the 2070s, southern corridors would nearly disappear under the RCP8.5 scenario, with the dispersal paths contracting northward. These findings underscore the urgency of implementing comprehensive conservation strategies, such as habitat restoration, corridor enhancement, and cross-border cooperation between China and Myanmar, to mitigate climate change impacts and safeguard the long-term survival of Skywalker hoolock gibbons. Full article

Uncovering the intricate relationships within the realm of ecosystem services (ESs) across various spatial and temporal dimensions, as well as their nonlinear relationships with natural–social factors, is a fundamental condition for regional ecosystem management. This study focuses on Honghe Prefecture, Yunnan Province, and it quantifies the supply of ESs at the grid and township scales, clarifies the interrelationships among ESs and influencing elements, and proposes cross-scale regional ecological management strategies. The findings indicate the following: (1) ESs exhibited spatial variability. In the last 20 years, the supply capacity of food production (FP) increased by about 46%, while other ESs showed a downward trend. (2) Synergistic effects among ESs primarily occurred between WY, habitat quality (HQ), carbon sequestration (CS), and soil conservation (SC), while trade-off effects mainly took place between FP and other ESs. (3) Significant and dramatic changes in the ecosystem service bundles were observed in the southern mountainous areas. At the grid scale, the overall area of the integrated ecological bundle declined by approximately 88%. However, the proportion of the HQ-CS key synergy bundle increased from 15.68% to 40.60%. Similar spatial patterns and trends were also observed at the township scale. (4) There was a notable reduction in the comprehensive supply of the ecosystem service index (ESI) in the southwest, in which human activities and climate drought factors played a major negative driving role, and some driving factors had threshold effects with the ESI. Existing research often ignores the nonlinear relationship between complex spatiotemporal dynamics and ecosystem services. Thus, this study constructed a comprehensive cognitive framework for regional ES status from the perspective of “supply–interaction–driving–threshold” for ESs, providing a more comprehensive understanding of regional ES management. Full article

Understanding post-fire vegetation recovery dynamics is crucial for damage assessment and recovery planning, yet spatiotemporal patterns in complex plateau environments remain poorly understood. This study addresses this gap by focusing on Yunnan Province, a mountainous plateau region with high fire incidence. We developed an innovative approach combining differenced Normalized Burn Ratio (dNBR) and visual interpretation on Google Earth Engine (GEE) to generate high-quality training samples from Landsat 5 TM/7 ETM+/8 OLI imagery. Four supervised machine learning algorithms were evaluated, with Random Forest (RF) demonstrating superior accuracy (OA = 0.90) for fire severity classification compared to Support Vector Machine (SVM) OA of 0.88, Classification and Regression Tree(CART) OA o f0.85, and Naive Bayes(NB) OA of 0.78. Using RF, we generated annual fire severity maps alongside the Land Surface Water Index (LSWI), Normalized Difference Vegetation Index (NDVI), and Normalized Burn Ratio (NBR) from 2005 to 2020. Key findings include the following: (1) fire severity classification outperformed traditional remote sensing indices in characterizing vegetation recovery; (2) distinct recovery trajectories emerged across severity levels, with moderate areas recovering in 7 years, severe areas transitioning within 2 years, and low severity areas peaking at 2 years post-fire; (3) southern mountainous regions exhibited 1–2 years faster recovery than northern areas. These insights advance understanding of post-fire ecosystem dynamics in complex terrains and support more effective recovery strategies. Full article

Citrus huanglongbing (HLB) is one of the most severe diseases affecting the citrus industry, with Diaphorina citri (Hemiptera: Liviidae) serving as its primary natural vector. To understand the genetic diversity and population structure of D. citri in the context of HLB diffusion, we analyzed 13 populations from the HLB diffusion frontier and 25 populations from epidemic areas in China. The HLB diffusion frontier areas refer to the peripheral regions of HLB distribution in China, including the western Zhejiang, southern Jiangsu, northern Jiangxi, northern Hunan, and eastern Sichuan provinces. In contrast, the HLB epidemic areas represent regions in China where HLB is actively widespread and causing significant impacts. We utilized mitochondrial genes (COI, ND5, and Cytb) of D. citri and housekeeping genes (dnaQ, rpoC, and argH) of its endosymbiont Candidatus Carsonella ruddii (Ca. C. ruddii) for this analysis. Our findings revealed that the D. citri and Ca. C. ruddii in different regions showed low haplotype diversity and nucleotide diversity. While the genetic variation in D. citri populations primarily occurred within populations, the endosymbiont showed contrasting patterns in the HLB epidemic areas. We identified three dispersal paths: (1) migration of the Yunnan population to Sichuan, Guizhou, and Guangxi; (2) movement of the Guangdong population to Fujian, Jiangxi, and Zhejiang; and (3) dispersal of the Guangdong population to Hunan and Guangxi. Our study suggests that D. citri populations at the HLB diffusion frontier are predominantly transmitted from neighboring epidemic areas. Full article

The evaluation of the carrying capacity of urban resources and the environment and the suitability of urban spatial development (referred to as “double evaluation”) is a fundamental prerequisite for territorial spatial planning. A scientifically planned urban spatial layout is key to balancing economic, social, and environmental benefits, which directly impacts urbanization levels and regional high-quality development. In this study, a double evaluation index system was established for the city cluster in central Yunnan based on the theories of “double evaluation” and main functional zones. The PLUS model was used to predict the distribution of future urban spatial patterns, considering factors like main function zones, and to optimize the spatial patterns of cities and towns in the study area. The findings are as follows. (1) The area of land suitable for urban construction in the study area is 25,107.51 km², mainly distributed in the southern and central urban areas, as well as in the Zhanyi and Qilin districts to the east. (2) More than 76% of the land designated for urban construction is located in suitable areas, with an area of 680.51 km², which represents only 2.71% of the total suitable land, indicating significant potential for further urban development. The PLUS simulation reveals that the urban area in the study area will reach 235.41 km² by the future, with 83.67% of urban construction space concentrated in suitable areas. Additionally, 69.11% of urban construction space and 74.53% of suitable land for urban construction are located in the key development area, which covers 618.43 km² and 18,713.28 km², respectively. This highlights the key development area’s crucial role in urban expansion and its significant potential for further development. Despite the region’s high level of economic activity and urbanization, there remains considerable potential for the expansion of towns over a wide area. This study provides valuable insights for optimizing urban spatial layouts, the allocation of national land space functions, and promoting orderly development. Full article

Xishuangbanna, located in southern Yunnan, China, is a vital tropical rainforest reserve supporting rich biodiversity, including the endangered Asian elephant (Elephas maximus). Increasing human activities, such as urbanization and agricultural expansion, have degraded habitats and intensified human–elephant conflicts, adding to the challenges of conservation. This study integrates habitat quality assessment and conflict risk analysis using the InVEST model across 2128 villages, considering land use and habitat threats like cropland and roads. The model reveals significant overlap between high-conflict zones and low-quality habitats near key reserves, underscoring the need for targeted conservation strategies. We propose establishing Ecological Source Areas (ESAs) to protect high-quality habitats and Ecological Restoration Zones (ERZs) to improve ecological conditions in low-quality, high-conflict zones. ESAs are essential for providing continuous ecosystem services and ensuring ecological security, while ERZs focus resources on areas with high conflict risk that urgently need restoration. Additionally, we recommend creating ecological corridors to connect fragmented habitats, enhance connectivity, support herd interactions, and reduce conflicts by expanding elephants’ safe roaming range. This integrated framework emphasizes habitat protection, ecological restoration, and conflict mitigation while accounting for human dynamics to support sustainable conservation. Reducing overlap between human and elephant activities remains a key objective. Future research should refine these models with more detailed data and extend their application to other regions, focusing on adaptive management and monitoring to address evolving ecological and human dynamics. Full article

Amid global climate change, recurrent drought events pose significant challenges to regional water resource management and the sustainability of socio-economic growth. Thus, understanding drought characteristics and regional development patterns is essential for effective drought monitoring, prediction, and the creation of robust adaptation strategies. Most prior research has analyzed drought events independently in spatial and temporal dimensions, often overlooking their dynamic nature. In this study, we employ a three-dimensional methodology that accounts for spatiotemporal continuity to identify and extract meteorological drought events based on a 3-month standardized precipitation evapotranspiration index (SPEI3). Measured by the SPEI3 index, the incidence of drought increased in the middle part of the basin, especially in some parts of Sichuan and Yunnan province, and the frequency of drought events decreased in the upper reaches. We evaluate drought events within the Yangtze River basin from 1980 to 2016 by examining five variables: chronology, extent, severity, duration, and epicenter locations. The results show that a total of 97 persisting drought events lasting at least 3 months have been identified in Yangtze River basin. Most events have a duration between 4 and 7 months. The findings indicate that while the number of drought events in the Yangtze River basin has remained unchanged, the intensity, duration, and severity of these events have shown a slight increase from 1980 to 2016. The drought events gradually moved from the western and southeastern parts of the basin to the central region. The most severe drought event occurred between January 2011 and October 2011, with a duration of 10 months and an affected area of 0.94 million km², impacting over fifty percent of the basin. Changes in wetness and dryness in the Yangtze River basin are closely related to El Niño/Southern Oscillation (ENSO) events, with a positive correlation between the intensity of cold events and the probability of extreme drought. This study enhances our understanding of the dynamics and evolution of drought events in the Yangtze River basin, providing crucial insights for better managing water resources and developing effective adaptation strategies. Full article

In recent years, tourism and leisure districts have become a pivotal aspect of China’s tourism development. Analyzing their spatial distribution characteristics and driving factors is essential for fostering comprehensive district tourism and promoting sustainable development, while also facilitating the profound integration of culture and tourism. This study undertakes a thorough investigation of the spatiotemporal patterns of national-level tourism and leisure districts in China, employing GIS spatial statistical analysis techniques, including the Average Nearest-Neighbor Index, Kernel Density Analysis, and Standard Deviation Ellipse. Additionally, this research identifies the principal driving factors affecting the spatial distribution of these districts through overlay analysis, buffer analysis, and geographic detectors. The findings reveal that (1) tourism and leisure districts exhibit a notable spatial clustering pattern, characterized by a predominance in the eastern regions and scarcity in the west, alongside a higher concentration in the south compared to the north, with a gradual decline in spatial density. (2) High-density tourism and leisure districts are predominantly located in the Yangtze River Delta and the Beijing–Tianjin–Hebei urban agglomerations, while regions of elevated density are situated in the southwest (notably in Sichuan, Chongqing, Guizhou, and Yunnan provinces). The centroids of the first to third batches of tourism and leisure districts have transitioned from southern to northern locations. (3) The population density factor exhibits the most substantial explanatory power regarding the distribution of tourism and leisure districts (q: 0.80528), followed by the added value of the tertiary industry (q: 0.53285), whereas the slope factor shows minimal influence (q: 0.00876). Furthermore, the distance to rivers of grade three and above, in conjunction with population density, constitutes the primary factor combination influencing the spatial configuration of tourism and leisure districts (q: 0.9101). Full article