Search Results (580)

Against the backdrop of global forest degradation and timber supply constraints, improving green production efficiency in forestry while securing timber supply is an important challenge for sustainable forest management. Treating China’s National Reserve Forest Policy (NRFP) as a quasi-natural experiment, this study uses panel data for 114 prefecture-level cities from 2011 to 2022, including 67 treated and 47 control cities. We employ a staggered difference-in-differences estimator based on group-time average treatment effects, together with transmission-channel analysis, difference-in-difference-in-differences (DDD), and a spatial difference-in-differences–spatial Durbin model (Spatial DID-SDM). The baseline estimates yield an overall ATT of 0.0149, indicating an average increase of 0.0149 index points in forestry GTFP for treated cities relative to the estimated counterfactual without the NRFP. This effect is approximately 1.49% of the sample mean of forestry GTFP (0.998) and remains stable across multiple robustness and sensitivity checks. NRFP implementation is separately associated with increases in capital deepening (CD) and physical labor productivity (PLP), while the lagged values of CD and PLP are each positively associated with forestry GTFP; these results are consistent with CD and PLP as potential transmission channels. The estimated NRFP effect is significantly weaker in resource-based cities and significantly stronger in economy-efficiency-oriented regions. Spatial effect decomposition shows that both the direct and indirect effects of the NRFP are positive and statistically significant. Under the alternative spatial weight matrix, both effects retain their direction and statistical significance, while the magnitude of the indirect effect remains broadly stable, suggesting that the positive spatial spillover effect of the NRFP on forestry GTFP is reasonably robust to the spatial weight matrix specification. These findings provide city-level empirical evidence for evaluating NRFP performance and informing differentiated policy design. Full article

Protected Natural Areas (PNAs) face a structural challenge in Tourist eXperience (TX) management: existing TX evaluation instruments were developed mainly for controlled commercial environments and do not account for the ecological variability, diverse visitor profiles, and dual conservation-recreation mandate that characterize these spaces. This article presents the development and appraisal of the PNAs TX Checklist (PNA-TX), a 41-item instrument designed to evaluate tourist experience quality in protected natural areas across six dimensions: Sensory, Emotional, Cognitive, Practical, Relational, and Sustainability. The instrument was developed following Stufflebeam’s Checklist Development Checklist (CDC) methodology, grounded in a systematic review of TX literature. It was appraisal through an initial review by three Tourism Administration students, followed by two sequential rounds of expert appraisal involving eight and nine practitioners, respectively, from Chilean national parks and private conservation reserves; the perceived usefulness of PNA-TX was also assessed with tourists of varied cultural backgrounds. This appraisal process indicates that the PNA-TX showed evidence of applicability, usefulness, and feasibility within the Chilean protected-area contexts examined by experts, complemented by preliminary evidence of perceived usefulness across a culturally diverse tourist sample. The PNA-TX addresses a gap in the literature by combining field-observable management conditions with experiential quality indicators specifically calibrated for the protected natural area context. It also supports sustainability-oriented management practices aligned with the United Nations Sustainable Development Goals (SDGs) 11, 13, and 15. Full article

In the primary spruce-fir-Korean pine forest affected by historical windthrow, soil water-holding capacity shows complex spatial associations with forest microenvironment and soil physicochemical properties. However, its spatial variability and multi-factor hierarchical association pathways remain poorly understood. Taking the primary spruce-fir-Korean pine forest on a historically windthrow-affected site in the Liangshui National Nature Reserve, Xiaoxing’an Mountains, China as the research object, geostatistics and partial least-squares structural equation modeling were used to analyze the spatial pattern of topsoil (0–20 cm) water-holding capacity and its environmental association pathways. The results showed saturated, capillary and field water-holding capacities of topsoil exhibited moderate variability and strong spatial autocorrelation (all nugget to sill ratios < 25%), showing a patchy distribution. No significant direct association was detected between windthrow mechanical disturbance intensity and topsoil water-holding capacity. Bulk density (path coefficient = −0.685, p < 0.001) and soil porosity (path coefficient = 0.273, p < 0.001) had significant direct associations with soil water-holding capacity, whereas soil particle size distribution showed no significant effect (p > 0.05). Canopy structure and understory microclimate exerted indirect associations with soil water-holding capacity via soil structure; litter showed no significant associative effect (p > 0.05). These results indicate that soil water-holding capacity on the historically windthrow-affected site was not randomly distributed, but presented an ordered patchy pattern closely related to in-plot micro-environmental factors. Full article

The standardized construction of ethograms and the quantitative comparison of behavioral differences are fundamental to animal behavioral ecology research. This study focused on the Yunnan snub-nosed monkey (Rhinopithecus bieti) inhabiting the Weixi area of the Baimaxueshan National Nature Reserve and the Mangkang area of the Mangkang Yunnan Snub-nosed Monkey National Nature Reserve. From 2017 to 2021, a total of 120 infrared cameras were deployed, yielding 21,813 image and video files containing R. bieti. Based on the PAE (Posture–Act–Environment) coding system, an ethogram and corresponding coding framework were constructed. In total, 16 postures, 84 acts, and 22 environmental factors were identified; 135 behaviors were defined and classified into 18 functional categories. On this basis, behavioral composition differences were quantitatively compared across seasons and geographic regions. The results showed that season significantly affected behavioral composition (F = 5.029, R² = 0.255, p < 0.01). Four behavioral categories exhibited significant seasonal fluctuations: Locomotive behavior (χ² = 12.97, p < 0.01), Ingestive behavior (χ² = 12.04, p < 0.01), Resting behavior (χ² = 26.18, p < 0.001), and Miscellaneous behavior (χ² = 29.92, p < 0.001). Locomotive behavior peaked in summer, whereas Ingestive behavior was at its lowest and Resting behavior at its highest in autumn. Geographic region also significantly influenced behavioral composition (F = 2.808, R² = 0.149, p < 0.01). These differences were mainly reflected in significantly lower Locomotive behavior (U = 13, p < 0.01) and higher Ingestive behavior (U = 13, p < 0.05) in the higher-elevation Mangkang group compared with the lower-elevation Weixi group. By integrating infrared camera with the PAE coding system, this study not only constructs an ethogram for R. bieti but also compares behavioral differences across seasonal and geographic dimensions. The findings demonstrate the comprehensive applicability of this technical pathway for macroscopic behavior recognition, frequency statistics, and difference analysis in wild primates, and provide fundamental data for further understanding the ecological driving mechanisms of behavioral plasticity and for differentiated conservation management of R. bieti. Full article

Mountain ecosystems serve as natural laboratories for studying biodiversity distribution along elevational gradients. This study was conducted at Hualongshan National Nature Reserve in the Daba Mountains, Shaanxi Province, using line transect surveys, mist-netting, and passive acoustic monitoring (PAM). We systematically examined the spatial variation and drivers of bird community diversity along the elevational gradient, integrating α and β diversity across taxonomic, functional, and phylogenetic dimensions. A total of 91 bird species from 8 orders and 33 families were recorded, among which breeding birds (84 species) were dominated by Oriental (55.95%) and Palaearctic (26.19%) species, reflecting significant transitional characteristics between the two realms. Alpha diversity exhibited a mid-elevation unimodal pattern, peaking at 1951~2250 m in the coniferous and broad-leaved mixed forest zone. β diversity decomposition revealed that taxonomic diversity was dominated by turnover, functional diversity by nestedness, and phylogenetic diversity by balanced contributions of both, indicating asynchrony among dimensions. Random forest models identified precipitation difference as the primary driver of taxonomic β diversity, while Enhanced Vegetation Index (EVI) difference dominated functional β diversity, revealing differentiated mechanisms by which water availability and vegetation productivity shape species composition and functional structure, respectively. Our findings highlight the asynchrony of multidimensional bird diversity, emphasizing that a single dimension cannot fully capture community assembly mechanisms, and provide theoretical and practical reference for mountain biodiversity conservation. Full article

Extreme hydrological events induced by climate change pose significant challenges to the ecological stability of river-connected lake-wetland systems. Poyang Lake, China’s largest freshwater lake, provides an ideal case for investigating landscape responses to compound drought and flood disturbances. This study quantifies the propagation process from meteorological drought to hydrological drought and identifies critical water level thresholds governing abrupt landscape transitions. By integrating remote sensing data, drought indices, Morphological Spatial Pattern Analysis (MSPA), and piecewise regression, we evaluated nonlinear landscape responses to extreme water level fluctuations. The results showed that the optimal lag time for lake water area response to meteorological drought was 21 days. Landscape connectivity exhibited nonlinear responses to water level variations, with 12.50 m and 12.73 m identified as critical thresholds for maintaining lake-wide connectivity and core deep-water habitats, respectively. The 9.75–14.44 m water level range was identified as the key sensitive interval associated with rapid landscape reorganization. Moreover, landscape responses showed significant spatial heterogeneity, with the Nanji Wetland National Nature Reserve being more sensitive to drought-induced fragmentation than the Poyang Lake National Nature Reserve. These findings provide quantitative thresholds and adaptive management implications for improving the resilience of floodplain lake-wetland systems under increasing hydrological extremes. Full article

Objectives: Individuals with type 2 diabetes (T2D) remain at high cardiovascular disease (CVD) risk. The pan-immune-inflammation value (PIV) integrates circulating neutrophils, monocytes, platelets, and lymphocytes but does not capture albumin-related nutritional and inflammatory reserve. We investigated associations between the PIV-to-albumin ratio (PIVA) and incident CVD, cardiovascular mortality, and disease progression in individuals with T2D. Methods: This prospective study included 15,355 UK Biobank participants with T2D and no baseline CVD. PIVA was calculated from peripheral blood cell counts and serum albumin and was natural log-transformed. Fine–Gray competing-risk and cause-specific Cox models were used to evaluate incident CVD and cardiovascular mortality. Multi-state models characterized transitions from T2D to CVD and death. We also examined nonlinear associations, renal biomarker mediation, joint associations with the CVD polygenic risk score and triglyceride–glucose index, sensitivity analyses, and external validation of cardiovascular mortality in the National Health and Nutrition Examination Survey. Results: During median follow-ups of 12.94 years for incident CVD and 14.49 years for cardiovascular mortality, 4829 incident CVD events and 514 cardiovascular deaths occurred. Each 1-unit increase in lnPIVA was associated with higher risks of incident CVD (subdistribution hazard ratio [sHR], 1.140; 95% confidence interval [CI], 1.088–1.194) and cardiovascular mortality (sHR, 1.449; 95% CI, 1.247–1.684). Associations were nonlinear. Higher lnPIVA was also associated with transitions from T2D to CVD, from T2D directly to cardiovascular death, and from incident CVD to cardiovascular death. Cystatin C explained a larger proportion of these associations than creatinine. Elevated lnPIVA identified excess cardiovascular risk across strata of genetic susceptibility and insulin resistance, and the findings were generally supported by sensitivity and external validation analyses. Conclusions: lnPIVA was associated with incident CVD, cardiovascular mortality, and adverse cardiovascular transitions in individuals with T2D. As an immune-inflammatory and albumin-based index, PIVA may help identify high-risk individuals beyond conventional cardiometabolic and genetic risk profiles. Full article

Traditional villages in ecologically sensitive areas face structural dilemmas between preservation-induced stagnation and excessive commercialization under the combined pressures of rural revitalization and ecological protection. This study investigates the spatial differentiation and revitalization strategies of 250 nationally recognized traditional villages in the Xin’an River Basin from a resilience-inspired spatial planning perspective. GIS-based kernel density estimation and the Nearest Neighbor Index were applied to characterize spatial distribution patterns, while GeoDetector was used to evaluate the explanatory power of key natural and anthropogenic factors. The Minimum Cumulative Resistance (MCR) model was used to construct revitalization-suitability zones; resilience capacities were not directly measured; instead, they were used as heuristic planning concepts for interpreting the three consolidated priority regions: Core Conservation (absorptive), Moderate Revitalization (adaptive), and Ecological Conservation (transformative/reserve). The results reveal a pattern of small-scale clustering and large-scale dispersion. A total of 69.2% of the villages were located within 1.5 km of rivers, and 95.2% were situated below 500 m in elevation. Distance to rivers (q = 0.2345) and distance to roads (q = 0.1441) showed the highest explanatory power among the eight candidate factors. The framework provides resilience-inspired spatial guidance for balancing heritage conservation, ecological protection, and rural revitalization. Full article

Mangroves are important coastal blue-carbon ecosystems, and accurate biomass estimation is essential for carbon stock assessment and ecological monitoring. To address the limitation of regional-scale biomass estimation caused by the scale mismatch between field plots and satellite pixels, this study selected the Zhangjiangkou National Mangrove Nature Reserve in Fujian Province as the study area and the mangrove distribution region of Fujian Province as the extrapolation area. A multiscale biomass estimation framework integrating field plots, unmanned aerial vehicles (UAVs), and satellite remote sensing was established. The results showed that (1) the optimal UAV-scale models achieved R² values of 0.69 and 0.78 for aboveground biomass (AGB) and belowground biomass (BGB), respectively, with corresponding root mean square error (RMSE) values of 18.55 and 9.52 t·ha⁻¹ and normalized root mean square error (nRMSE) values of 0.14 and 0.17 demonstrating reliable predictive performance; (2) after introducing UAV-derived bridging labels, the R² of the AGB model increased from 0.24 to 0.64, while the RMSE decreased from 29.02 to 10.86 t·ha⁻¹. Similarly, the R² of the BGB model increased from 0.43 to 0.63, accompanied by a reduction in RMSE from 14.89 to 6.35 t·ha⁻¹, demonstrating a substantial improvement in satellite-scale biomass estimation accuracy; (3) the total AGB and BGB of mangroves in Fujian Province were estimated at 58,768.60 t and 24,575.14 t, respectively, with high-biomass areas mainly distributed along the coastal regions of Zhangzhou and Quanzhou. Unlike conventional field-to-satellite extrapolation approaches, the proposed framework introduces UAV-derived biomass maps as intermediate bridging labels for pixel-level supervised learning, thereby establishing an effective link between field measurements and satellite observations. This strategy effectively reduces the scale mismatch between field and satellite data, significantly improves satellite-scale biomass estimation accuracy, and provides a transferable and scalable framework for regional mangrove biomass mapping and blue-carbon assessment. Full article

Although many studies had been conducted on soil microbial communities in forest ecosystems before this one, how the diversity and network complexity of soil microbial communities evolved throughout the succession of karst forests remained unclear. We collected soil samples from three vegetation successional stages (grassland stage, shrub stage and arbor stage) in Maolan National Nature Reserve, Guizhou Province, China, and applied high-throughput sequencing technology to explore soil microbial diversity, community composition, co-occurrence network characteristics and their internal correlations. The results showed that the succession process significantly affected soil microbial diversity (p < 0.05). Bacterial diversity increased by 12.33% as succession proceeded, whereas fungal diversity declined by 37.50%. The dominant microbial communities exhibited obvious stage-specific characteristics. For bacteria, Bacillaceae served as a universally dominant taxon. Paenibacillaceae and Thermoactinomycetaceae were enriched in the grassland (CD) stage, and the relative abundance of Streptosporangiaceae reached its maximum in the arbor (QM) stage. For fungi, Trimorphomycetaceae and Hypocreaceae were ubiquitous dominant groups. Aspergillaceae possessed the highest relative abundance in the CD stage, while Clavicipitaceae peaked in relative abundance in the QM stage. The complexity of bacterial co-occurrence networks rose with succession, whereas fungal network complexity decreased. Both positive and negative linkages in bacterial networks increased over succession, while both types of connections in fungal networks declined. Soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP) and N/P ratio exerted the strongest influences on bacterial communities and bulk density; SOC and TN were the key drivers structuring fungal assemblages. Micromonosporaceae and Xanthobacteraceae showed significant positive correlations with TP and N/P ratio (p < 0.05), whereas Thermoactinomycetaceae and Oscillospiraceae presented significant negative correlations with these two indicators (p < 0.01). Clavicipitaceae had strong positive correlations with SOC and TN (p < 0.01), and Herpotrichiellaceae together with Aspergillaceae displayed significant negative correlations with SOC and TN (p < 0.05). This study clarified the regulatory effects of karst forest secondary succession on soil microbial communities and provided theoretical evidence for the ecological restoration of karst regions. Full article

Poyang Lake is a typical floodplain lake hydrologically linked to the middle-lower Yangtze River. Its peripheral saucer-shaped sub-lakes undergo seasonal hydrological alternation between isolation and connectivity driven by annual water level fluctuations. To date, the coupling between seasonal hydrological rhythms and zooplankton metacommunity assembly in these saucer floodplain lakes remains poorly understood. In this study, four representative saucer sub-lakes within the Poyang Lake National Nature Reserve (Banghu, Zhonghuchi, Shahu and Dahuchi) were selected as research objects. Seasonal quantitative zooplankton surveys and synchronous hydro-physicochemical monitoring were conducted across four hydrological phases from 2012 to 2013: low-water isolation (spring), high-water connectivity (summer), water recession transition (autumn), and extreme low-water closure (winter). We systematically explored how water level fluctuations regulate zooplankton metacommunity assembly processes. In total, 95 zooplankton species were identified, among which rotifers (68 species) constituted the absolute dominant taxon, and 15 species were identified as year-round absolute dominants exhibiting regular seasonal succession in response to hydrological shifts. Our results demonstrate that hydrological connectivity plays a strong role in regulating the relative strength of species dispersal and environmental filtering. During spring and winter, complete hydrological isolation blocked inter-lake species exchange, making local environmental filtering the main driver of metacommunity assembly. Isolated sub-lakes harbored fewer total species but abundant endemic taxa, accompanied by pronounced spatial community heterogeneity. When water levels exceeded the 17.3 m threshold in summer, full water exchange between sub-lakes and the main lake coincided with widespread species dispersal, which appeared to represent the primary assembly process. The four sub-lakes shared 23 co-occurring species during this period, with highly homogenized community structures and minimal spatial differentiation (Global test: R = 0.47, p = 0.001). In autumn, receding water levels weakened inter-lake connectivity, such that environmental filtering and dispersal jointly structured zooplankton metacommunities; significant spatiotemporal differences were detected in zooplankton density, biomass and α-diversity (p < 0.05). Critical hydro-physicochemical factors of environmental filtering included water temperature, chlorophyll a, pH, electrical conductivity and turbidity, yet the dominant limiting factor varied spatially across sub-lakes due to divergent basin topography and water residence time. Species co-occurrence network analysis revealed that zooplankton communities achieved the highest stability during the fully connected summer phase. In early autumn water drawdown, species association networks became fragmented, and community stability reached its annual minimum. This study elucidates the mechanistic link between floodplain lake hydrological rhythms and zooplankton metacommunity assembly, providing theoretical support and baseline data for wetland biodiversity conservation and ecosystem management of Poyang Lake floodplains. Full article

Extreme droughts can rapidly reshape surface-water patterns in river-connected floodplain wetlands, yet the fine-scale responses of individual dish-shaped sub-lakes remain insufficiently resolved. This study focused on the 2022 extreme drought in Poyang Lake, China’s largest freshwater lake and a globally important floodplain wetland system. The objectives were to quantify wetland landscape changes during the 2022 extreme drought event and to compare the heterogeneous responses of dish-shaped sub-lakes under contrasting surface-water linkage and management-context settings. We developed a high-resolution wetland monitoring framework on the Google Earth Engine platform by integrating Sentinel-2 multispectral imagery, Sentinel-1 synthetic-aperture radar, and the Dynamic World land-cover product. This multi-source approach was designed to reduce spectral confusion among turbid water, saturated mudflats, and exposed lakebeds during extreme low-water stages. Monthly wetland maps were generated for the Poyang Lake National Nature Reserve and compared with a five-year historical baseline from 2017 to 2021. The framework achieved an overall accuracy of 87.44%, with a Kappa coefficient of 0.80. The results revealed a rapid wet-to-dry transition in 2022. The water area contracted by 78.1% from July to September and remained 73.6–74.7% below the historical baseline from September to November. This contraction was accompanied by extensive observable surface-water fragmentation, apparent loss of visible surface-water linkage among sub-lakes, and substantial wetland habitat contraction. Sub-lakes exhibited clearly differentiated drought responses. Sub-lakes with stronger visible surface-water linkage to the main lake generally experienced more rapid water loss during recession, whereas reserve-managed or facility-present sub-lakes retained residual water to varying degrees and may have provided important refugial habitats for waterbirds and aquatic species. These findings suggest that surface-water linkage condition, local topographic setting, and 2022 management context were jointly associated with the heterogeneous drought responses of sub-lakes. The proposed framework provides a tool for monitoring wetland landscape changes associated with extreme drought events, assessing ecological vulnerability, and supporting adaptive water-level management under intensifying climate extremes. Full article

Rapid changes in coastal salt marsh vegetation highlight the need for accurate monitoring to support sustainable management. This study aims to track annual salt marsh landscape dynamics and discuss vegetation succession mechanisms. A novel approach was proposed to improve the discrimination of different plant species by integrating phenological features derived from NDVI time series, thereby enhancing salt marsh classification. The results showed that the proposed method achieves an overall accuracy of 93.6%, significantly outperforming schemes based solely on spectral indices (81.6%) or combined spectral and textural features (85.5%) (p < 0.05). The overall accuracy of annual classification maps for the Yancheng National Nature Reserve wetland from 1994 to 2025 averaged 90.5%, with a minor fluctuation of 2.8%, demonstrating the accuracy and reliability of this method for long-term monitoring of salt marsh landscapes. Annual classification maps revealed that the encroachment of Spartina alterniflora and Phragmites australis has intensified the fragmentation of Suaeda salsa. Notably, eradication efforts targeting Spartina alterniflora appear to have contributed to controlling this invasive species (decreasing by 33.22 km²) and restoring native species (increasing by 2.56 km²). This method serves as a reference for advancing salt marsh landscape classification frameworks. Full article

An excavation-induced clayey landslide in Jianshui County, Yunnan Province, China, threatens a national refined oil pipeline near the rear slope. Field investigation, borehole logging, laboratory testing, and three-dimensional finite-element analyses were integrated to investigate the excavation–rainstorm instability mechanism and evaluate circular anti-slide piles with toe backfilling. Under natural excavation, the reported factor of safety was 1.39, and the maximum displacement was 2.35 mm. Under a 60 mm/day rainstorm, increased pore-water pressure and saturation in the shallow sliding mass and strongly weathered claystone, together with saturated-state strength parameters, reduced the shear-strength reserve. The deformation and stability analyses yielded a maximum computed displacement of 1.36 m and a factor of safety of 0.95, respectively, indicating pronounced pre-failure deformation and loss of stability. After mitigation, the factor of safety increased to 1.41, while the maximum slope and pile-head displacements were both approximately 6.90 mm. The pile row redistributed nonuniform landslide thrust and reduced deformation transfer toward the pipeline. The results are site-specific engineering estimates for the investigated rainfall and parameter conditions. Full article

Groundwater nitrate contamination imposes a safety concern. Mitigating groundwater nitrate levels requires a quantitative assessment of source contributions, which is also challenging to estimate considering the data uncertainty and the agriculture environmental complexity. The Pineland Sand Region in north central Minnesota, United States, features sandy soils and has a mixed land-use landscape of agriculture and natural background, with part of the area located within the White Earth Nation Reservation region. We analyzed the land-use patterns and identified nitrate contaminant sources in nature, wetlands, row crops, pasture, and urban areas. To estimate the nitrate source apportionment and its uncertainty in this study area, we first characterized these sources using calcium, sulfate, chloride, and sodium, and then applied a Bayesian mass-balance mixing model using a Monte Carlo Markov Chain approach in 164 groundwater wells and further obtained the probability distributions of the fractional contributions from those specific sources. The results show that nature and wetlands source fractions dominate sites with negligible agriculture impacts, while row crop and pasture sources are estimated with higher contaminant contributions in sites subject to more intensive agriculture management. We also discussed a few specific sites’ contaminant source fractions and suggest a future source characterization scheme to advance groundwater nitrate understanding in the study area. Full article