Table of Content

18 February 2026, Volume 37 Issue 2

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Multi-scenario simulation of synergistic dynamics in ecosystem services within Shennongjia National Park

ZHENG Binbin, ZENG Jie, CUI Xinyu, LI Jiangfeng, YANG Meng, YANG Tian

2026, 37(2):  325-336.  doi:10.13287/j.1001-9332.202602.021

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Understanding the trade-offs, synergies, and dynamics among ecosystem services (ESs) under both current and future conditions is crucial foundation for promoting holistic ecosystem conservation and scientific management of national park. Using the PLUS and InVEST models, we assessed land use and ES changes of Shennongjia National Park in 2030 and 2050 under three scenarios: Natural development, ecological conservation, and tourism development. We used Spearman correlation analysis and K-means clustering to identify trade-offs and synergies among ESs, delineate the functional structure of ES bundles, and examine their dynamics. The results showed that different ESs exhibited distinct evolutionary trends from 2020 to 2050. Recreational services remained relatively stable overall. Water yield, soil conservation, and habitat quality showed declining trends, with the most significant reductions under the tourism development scenario by 359769.00 mm, 28388.70 t, and 0.11, respectively. Carbon storage increased significantly only under the ecological conservation scenario, with a gain of 102096.71 t. Relationships among ESs under different scenarios were predominantly synergistic and showed notable changes. Under the natural development and tourism development scenarios, trade-offs weakened while synergies strengthened. The relationship between carbon storage and water yield shifted from trade-off to synergy. Under the ecological conservation scenario, trade-offs and synergies remained largely unchanged. Based on K-means clustering of ecosystem service trade-offs and synergies, four distinct types of ES bundles were identified: strict protection, science education and recreation, community livelihood, and ecological restoration. The spatial patterns of ES bundles showed minimal variation and remained relatively stable across different scenarios. Based on the distribution patterns and internal characteristics of different ES bundles, we proposed corresponding ecological management strategies to provide a scientific basis for the holistic conservation of national park ecosystems.

The perceptions of community residents on the importance and satisfaction of ecosystem services and their influencing factors: A case study of Wolong Nature Reserve, China

ZHAO Lexin, HUANG Yiqiang, MA Wenhui, XU Jianying

2026, 37(2):  337-346.  doi:10.13287/j.1001-9332.202602.026

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Nature reserves are of great significance in maintaining the supply of ecosystem services and sustaining development of local livelihoods. It is important to understand the perceptions of community residents on the importance and satisfaction with ecosystem services in protected areas, which is helpful for prioritizing ecosystem services and coordinating the relationship between ecological protection and resident livelihood development. With Wolong Nature Reserve as a case, we used the participatory rural appraisal method to the perceptions of community residents regarding the importance and satisfaction of ecosystem services. We further employed the importance-satisfaction analysis and multiple regression analysis to examine the differences in their perceptions of various ecosystem services and the influencing factors. The results showed that there were significant differences between the importance and satisfaction for the all types of ecosystem services, except for the regulating service of air purification. Importance-satisfaction analysis indicated that six ecosystem services (freshwater provision, natural disaster prevention, soil fertility maintenance, pest control, scientific knowledge and environmental education, and recreational tourism) were identified as high importance-low satisfaction, which requires high priority in reserve management. Local perceptions of ecosystem services were influenced significantly by the educational level, livelihood type, and geographical location. Residents with different education levels, livelihood types, and geographical locations exhibited different perceptions of the importance and satisfaction with ecosystem services. Among these, livelihood type and geographic location jointly affected residents’ perception of importance and satisfaction, while educational level only had a significant impact on satisfaction perception.

Regional unlocking path in the north and south foothills of the Qinling Mountains from land use perspective

LI Lingyan, LI Haojie, DUAN Mimi

2026, 37(2):  347-357.  doi:10.13287/j.1001-9332.202602.022

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The Qinling Mountains contain the largest forest ecosystem in central China. Examining the spatiotemporal variations of urban carbon lock-in and the pathways for unlocking it on the northern and southern piedmont of the Qinling hinterland is of great significance for achieving carbon balance in central and western China. Based on panel data from seven cities on the northern and southern piedmont of the Qinling Mountains from 2008 to 2022, we mea-sured regional carbon lock-in levels and carbon budgets from a land-use perspective, and investigated the spatio-temporal trends. We applied fuzzy-set qualitative comparative analysis to identify the high-carbon and low-carbon configuration effects of regional carbon lock-in at both macro and micro levels. The results showed that the degree of carbon lock-in in cities on the northern and southern piedmont of the Qinling Mountains increased from 1.79 to 5.61 and exhibited a certain degree of spatial clustering between 2008 and 2022. Net carbon emissions ranged from 31.22 Mt to 113.14 Mt, while carbon sinks remained in the range of 18 Mt to 21 Mt. The ratio of total carbon emission from construction land to that from cropland was 2.96:1. At the macro scale, regional carbon lock-in could be attributed to three configuration types: weak carbon sink function, gap in regulatory function, and misaligned industrial structure. At the micro scale, we identified nine high-carbon and ten low-carbon configurations. The main drivers of carbon emissions from natural ecosystem, construction land, and cropland were environmental regulation, industrial structure, and cropping structure, respectively. The degree of carbon lock-in in cities on the northern and southern piedmont of the Qinling Mountains followed a “slow-fast-slow” growth pattern. Spatially, it was characterized by lower in the south and higher in the north, with clustering that diffused from core cities to surrounding areas. On the basis of implementing overarching environmental policies, each region should select appropriate enhancement pathways in line with resource endowments and carbon lock-in drivers, so as to achieve the goal of carbon unlocking.

The coupling of electricity consumption carbon intensity and green transformation development in the Yangtze River Economic Belt urban agglomerations

DOU Haonan, CHEN Si, LIU Hai, SHI Xuerui, WANG Run

2026, 37(2):  358-370.  doi:10.13287/j.1001-9332.202602.027

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Promoting the synergistic optimization of electricity carbon emission reduction and green transition development is an important way to achieve regional ecological security and high-quality development. We employed a coupling coordination model to measure the coordination between electricity consumption carbon intensity and green transition development in the three urban agglomerations (urban agglomeration of Yangtze River Delta, Middle Reaches of the Yangtze River and Sichuan-Chongqing) of the Yangtze River Economic Belt from 2010 to 2021. We used Kernel density estimation and the Dagum Gini coefficient to reveal the spatio-temporal variations and regional heterogeneity, and constructed a Tapio decoupling model to analyze the decoupling effects between them. The results showed that the electricity consumption carbon intensity of the three urban agglomerations showed a monotonic decreasing trend at the annual scale from 2010 to 2021, while green transition development index firstly increased and then slowly declined. The coupling coordination degree between the two fluctuated decreased from 0.50 to 0.47, spatially presenting a decreasing trend from east to west. The overall imbalance in coupling coordination exhibited a gradual annual improvement, with the Dagum Gini coefficient decreasing from 0.10 to 0.08. There were significant spatial disparities in coupling relationship between electricity consumption carbon intensity and green transition development among the three urban agglomerations. The gap of coupling coordination between the Yangtze River Delta urban agglomeration and the other two agglomerations was gradually widening, while that between the Sichuan-Chongqing urban agglomeration and the Middle Reaches of the Yangtze River urban agglomera-tion was gradually narrowing. From 2010 to 2015, the decoupling effect between electricity consumption carbon intensity and green transition development of the three urban agglomerations were predominantly characterized by strong decoupling. From 2016 to 2021, negative decoupling became dominant. The average decoupling elasticity value increased from -0.636 to 0.282. By revealing the synergistic evolution between electricity consumption carbon intensity and green transition development in the Yangtze River Economic Belt, our results provide an important reference for formulating differentiated carbon reduction policies and advancing ecological conservation and green development at the regional level.

Response of non-structural carbohydrates in leaves of different life-form plants to altitude in secondary Betula platyphylla forests in mountainous area of northern Hebei, China

WANG Xumin, LIU Jinhua, LI Chenghao, WANG Riu, ZHAO Shuaiming, XU Xuehua

2026, 37(2):  371-380.  doi:10.13287/j.1001-9332.202602.008

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We measured the contents of starch, soluble sugars, and non-starch carbohydrates (NSC) in leaves of 60 common plant species (trees, shrubs, and herbaceous plants) from Betula platyphylla secondary forests across an altitude gradient (950, 1150, 1350, 1550, and 1750 m) in the northern Hebei mountainous region and analyzed their relationships with environmental factors. The results showed that both trees and shrubs exhibited significantly higher soluble sugar and NSC contents than herbaceous plants, while the starch-to-soluble sugar ratio (SC/SSC) was significantly lower in woody species, indicating a tendency to maintain higher carbon storage levels. With increasing altitude, NSC contents in trees first decreased and then increased, shifting from carbon limitation to growth limitation as a response to environmental stress, demonstrating a flexible trade-off strategy between ‘growth’ and ‘energy storage’. In contrast, NSC in shrubs and herbaceous plants increased significantly with altitude, dominated by growth limitation, reflecting a conservative strategy focused on carbon accumulation under low-temperature stress. The mixed-effects model revealed that altitude was the key driver of NSC variation, with interspecific differences being the primary source of leaf NSC variation. Redundancy analysis indicated that the first two principal components explained 87.6%, 79.9%, and 93.1% of the cumulative variance for trees, shrubs, and herbaceous plants, respectively. The main influencing factors were soil moisture and total nitrogen for trees; soil pH, available phosphorus, and mean temperature of the growing season for shrubs; and, mean temperature of the growing season, soil moisture, and pH for herbaceous plants. This study revealed the differential regulation of hydrothermal conditions and nutrient supply on carbon balance of different plant life forms, and clarified that life form is a key dimension to explain the diversity of plant adaptation strategies to altitude gradient.

Altitudinal variations of stem and leaf anatomical structures in Juniperus tibetica

WU Zhengjie, LIN Ling, ZHANG Yan, ZHANG Yiti

2026, 37(2):  381-388.  doi:10.13287/j.1001-9332.202602.006

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Juniperus tibetica is a constructive species on the Qinghai-Xizang Plateau. To investigate its ecological adaptation to the alpine environments along altitude gradients, we measured the anatomical structural traits of two-year-old branches (stem and leaves) across six altitude sampling sites within its main distribution range (3600-4600 m). With increasing altitude, J. tibetica leaves enhanced stress resistance, photosynthetic capacity, and transport capacity by increasing upper epidermal cuticle thickness, palisade tissue thickness, palisade cell length, palisade cell length/width ratio, and vascular tissues (leaf xylem and phloem). With rising altitude, stems improved cold resistance and optimized anti-embolism characteristics and water transport efficiency by increasing xylem proportion (stem xylem/stem), pith proportion (pith/stem), and decreasing tracheid area while increasing tracheid density. There were significant correlations among stem tracheid characteristics (tracheid density, tracheid area, tracheid wall thickness), leaf palisade tissue thickness, and leaf epidermal cuticle thickness of J. tibetica at different altitudes, reflecting the functional connections among stem water transport, leaf photosynthesis, and protective functions. The most plastic anatomical traits in stems and leaves were equivalent pith diameter (0.51) and leaf resin canal thickness (0.35). J. tibetica developed a comprehensive adaptation pattern to high-altitude environments through plastic adjustment of anatomical structures and the coordination among water transport traits, photosynthetic traits, and protective traits.

Seasonal responses of the quantity and composition of root exudates in Cunninghamia lanceolata to drought

ZHOU Heng, LI Jiayu, DENG Cui, JIANG Yongmeng, LYU Maokui, XIE Jinsheng

2026, 37(2):  389-398.  doi:10.13287/j.1001-9332.202602.007

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We simulated drought through 50% isolated rainfall exclusion and collected fine root exudates of Cunninghamia lanceolata during dry and wet seasons. Combined with total organic carbon (TOC) measurements and untargeted metabolomics (LC-MS) analysis, we investigated the seasonal responses of exudation rate and chemical composition of fine root exudates to drought stress. The results showed that there were significant seasonal variations in drought effects on root exudates. During dry season, the unit root length exudation rate and TOC concentration of root exudates decreased by 72.7% and 74.6%. In wet season, they increased by 58.0% and 35.4%, respectively. Organic acids, phenols, and amino acids were the dominant types in the root exudates under drought conditions. In dry season, defensive secondary metabolites such as phenols (e.g., phloroglucinol), flavonoids (e.g., catechin), and phenolic compounds (e.g., methyl mandelate) significantly increased, contributing to enhanced antioxidant capacity and regulation of rhizosphere microbial communities. In contrast, primary metabolites like sugars (e.g., glucose, deoxyribose) and organic acids (e.g., palmitic acid, 2-methylglutaric acid) significantly increased in wet season, promoting osmotic regulation and soil nutrient activation in C. lanceolata. Our results suggest that C. lanceolata adopts a “dry season defense, wet season attack” carbon allocation strategy to cope with drought stress, employing “conservative defense” through defensive secondary metabolites in dry season and “active adaptation” via resource-acquisitive primary metabolites in wet season.

Molecular characteristics of soil organic carbon and temperature sensitivity of soil respiration in the permafrost forest region of the Greater Khingan Mountains, Northeast China

SUN Haiming, HUO Changfu, YIN Liming, HE Yanghui,WANG Peng

2026, 37(2):  399-408.  doi:10.13287/j.1001-9332.202601.020

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As the second largest permafrost carbon reservoir in China, the stability of soil organic carbon (SOC) in the permafrost region of the Greater Khingan Moutains plays an important role in regulating climate change. To reveal the molecular characteristics of SOC and their influence on mineralization process, we collected surface soil samples (0-10 cm) from both the discontinuous and sporadic permafrost zones. Soil organic carbon molecular composition and diversity were characterized using Fourier transform attenuated infrared (FTIR) spectroscopy. SOC mineralization dynamics at 10 ℃ and 20 ℃ were examined with a 9-week laboratory incubation experiment. We further explored the coupling relationship between temperature sensitivity (Q₁₀) and molecular characteristics. The results showed that: SOC functional group composition and molecular diversity showed significant spatial heterogeneity, primarily governed by permafrost type. The discontinuous permafrost zone exhibited significantly higher abundances of aromatic (C=C, COO-) and alkyl (C-H) groups but a lower abundance of alcohol and phenol (O-H) groups compared to the sporadic permafrost zone. Molecular diversity was significantly higher in the discontinuous zone and was correlated with soil pH and water holding capacity (WHC). Warming significantly enhanced SOC mineralization, with cumulative mineralization at 20 ℃ being 2.1-2.3 times greater than that at 10 ℃. The Q₁₀ values ranged from 1.1 to 1.9, and showed significant positive correlations with labile components, such as aliphatic (C-H) and amide (N-H) groups. Those results indicated that the rapid response of these active carbon pools was key to driving temperature sensitivity. Through elucidating the regional coupling between SOC molecular characteristics and temperature sensitivity in the permafrost of the Greater Khingan Mountains, our results offer a molecular-scale theoretical basis for accurately assessing the permafrost carbon-climate feedback potential.

Effects of thinning on soil extracellular enzyme activities and their stoichiometric ratios in Pinus koraiensis plantations

YANG Yelei, WEN Hairui, YANG Yuchun, JIAO Chunjing, MA Chang, WANG Fang, WANG Jun, LIU Yue

2026, 37(2):  409-416.  doi:10.13287/j.1001-9332.202602.001

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We analyzed the seasonal dynamics (May, July, and September) of soil extracellular enzyme activity and its stoichiometric ratio in Pinus koraiensis plantations in Zhangguangcai Ridge, under thinning intensities of 0 (control), 10% (weak thinning), 20% (moderate thinning), and 30% (heavy thinning). The results showed that thinning increased the content of soil hydrolyzed nitrogen, available phosphorus, and available potassium, as well as the activities of cellulase, β-glucosidase, N-acetyl-β-glucosidase, and acid phosphatase. Except for the highest acid phosphatase activity in May, all enzyme activities reached their peak in July. The enzyme stoichiometry ratio (E_C:N:P=1:0.83:1.13) in July was lower than that in May (E_C:N:P=1:0.91:1.30) and September (E_C:N:P=1:0.91:1.26). Compared with weak and heavy thinning, the soil extracellular enzyme stoichiometry ratio was sma-ller under moderate thinning intensity, phosphorus limitation was alleviated, and carbon limitation was strengthened. Soil organic matter, hydrolyzed nitrogen, available phosphorus, and available potassium were important factors affecting soil extracellular enzyme activity and stoichiometry. Moderate thinning intensity could significantly improve soil nutrients, increase extracellular enzyme activity, and alleviate phosphorus limitation in P. koraiensis plantations.

Impact of forest succession on soil microorganisms and soil multifunctionality in subtropical forests

GAO Shuo, LIAO Hong, XU Songbai, YANG Wenrong, LIU Shuguang, GAO Dandan

2026, 37(2):  417-426.  doi:10.13287/j.1001-9332.202602.005

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This study focused on the early-, mid- and late-stage of subtropical forests, as represented by Cunninghamia lanceolata plantations (with stand ages of 5, 10, and 20 years), the mixed coniferous-broadleaf forests, and broadleaf forests, respectively. Using real-time fluorescence quantitative PCR and high-throughput sequencing techniques, we investigated the variations of rare and dominant soil microbial groups and soil multifunctionality across the succession stages. The results showed that forest succession altered the composition and structure of rare and dominant groups of microbial communities, significantly increased the abundance of dominant and rare soil microorganisms, but reduced their diversity. As succession progressed, the relative abundance of the rare bacterial phylum Planctomycetes significantly increased, the relative abundances of the phyla Bacteroidota, Chloroflexota, Gemmatimonadota, and Proteobacteria significantly decreased, while the relative abundance of the dominant fungal phylum Zygomycota significantly increased. With forest succession, soil multifunctionality significantly improved. Soil multifunctionality indices increased by 51.4%, 67.2%, 80.1%, and 69.2% in the 10-year-old C. lanceolata plantation, the 20-year-old C. lanceolata plantation, coniferous-broadleaved mixed forests, and broad-leaved forests respectively, compared to 5-year-old C. lanceolata plantation. Soil multifunctionality was significantly correlated with the abundance and diversity of dominant microorganisms but not with rare microorganisms, suggesting that dominant soil microorganism species might contribute more to soil multifunctionality than rare species. Soil nutrient content was identified as a key factor influencing rare and dominant microbial groups. Forest succession significantly enhanced soil multifunctionality, and dominant species may play a more critical role in maintaining soil multifunctionality compared to rare species.

Responses of soil microbial carbon use efficiency to nitrogen addition in mid-subalpine zonal forests of central Yunnan, China

ZHANG Long, LIANG Xiaoling, HOU Zheng, CHEN Wen, WANG Shaojun, SHU Haiyuan, SONG Yali

2026, 37(2):  427-440.  doi:10.13287/j.1001-9332.202602.004

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Soil microbial carbon use efficiency (CUE) reflects the proportion of absorbed carbon allocated to biomass synthesis by microorganisms. Investigating changes in soil microbial CUE under nitrogen addition would contribute to a deeper understanding of soil carbon sequestration potential in forest ecosystems. To investigate the responses of soil chemical properties, microbial biomass, and extracellular enzyme activity to nitrogen addition, we conducted a nitrogen addition experiment with six levels (0 (CK), 50 (N₅₀), 100 (N₁₀₀), 150 (N₁₅₀), 200 (N₂₀₀), 250 kg·hm^-2·a^-1(N₂₅₀)) in subalpine evergreen broad-leaved forest and Quercus aquifolioides forest in central Yunnan. Microbial CUE was calculated using a biogeochemical model. Then, we examined the responses of soil microbial CUE to nitrogen addition. The results showed under nitrogen addition, soil microbial CUE in evergreen broad-leaved forest exceeded that in Q. aquifolioides forest. Both forest types showed higher microbial CUE in the 0-10 cm soil layer than in the 10-20 cm layer. In evergreen broad-leaved forest, soil microbial CUE first increased then decreased with rising nitrogen addition levels decreasing by 2.9%-41.3% compared to the control. In contrast, Q. aquifolioides forest exhibited a pattern with a positive impact of high nitrogen levels but a negative effect of low nitrogen levels. Under N₂₀₀ and N₂₅₀ treatments, CUE significantly increased by 8.1% and 11.6%, while it decreased under other nitrogen addition treatments. The primary factors influencing soil microbial CUE in evergreen broad-leaved forest were bacterial and fungal community α-diversity and soil pH, whereas the factors were bacterial and fungal community α-diversity, soil NO₃^--N, and pH in Q. aquifolioides forest. The dominant groups differed between the two forest types, and the changes in community structure significantly influenced soil microbial CUE. Forest type, nitrogen addition, and soil depth jointly determined the variations in CUE for both evergreen broadleaf and Q. aquifolioides forest, indicating that the response of ecosystem carbon storage potential to nitrogen deposition exhibited significant ecological specificity.

Soil regulatory effects on the decomposition of different litter components in Pinus massoniana plantation under nitrogen and phosphorus additions

LI Jing, ZHOU Yongwei, SHEN Yafei, ZENG Lixiong, LIU Changfu, CHENG Ruimei, XIAO Wenfa

2026, 37(2):  441-452.  doi:10.13287/j.1001-9332.202602.009

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In this study, we conducted a two-year nitrogen and phosphorus addition experiment with six treatments: control (0 kg N·hm^-2·a^-1, 0 kg P·hm^-2·a^-1), phosphorus (30 kg P·hm^-2·a^-1), low nitrogen (30 kg N·hm^-2·a^-1), low nitrogen + phosphorus (30 kg N·hm^-2·a^-1, 30 kg P·hm^-2·a^-1), high nitrogen (90 kg N·hm^-2·a^-1), and high nitrogen + phosphorus (90 kg N·hm^-2·a^-1, 30 kg P·hm^-2·a^-1). We investigated the decomposition of different litter components of aboveground (leaf, branch, fruit) and fine root litter (class Ⅰ-Ⅲ roots) in Pinus massoniana plantation, examined their relationships with soil chemical factors (e.g., pH, organic carbon, total nitrogen) and hydrolytic enzyme activities (e.g., α-1,4-glucosidase). We further quantified the relative contributions of soil factors to nutrient residue (e.g., soluble sugars, starch) and decomposition coefficients (k) following variation partitioning analysis. The results showed that decomposition coefficients varied significantly among litter components in the same treatment, with branches (k=0.42-0.49) being lower than leaves and fruits, and first-order roots (k=0.42-0.51) being lower than higher-order roots. Compared with single-nutrient addition, the low nitrogen + phosphorus treatment significantly enhanced litter decomposition and nutrient release. In contrast, high nitrogen treatment reduced soil pH by 23.1% and markedly inhibited decomposition. The high nitrogen + phosphorus treatment raised pH by 13.9%, effectively mitigating the adverse effect of high nitrogen. Soil enzyme activity and chemical factors jointly drove litter decomposition, with the independent contribution of enzyme activity (5.1%-15.2%) being overall higher than that of chemical factors (0.7%-6.5%). Soil enzyme activity was the key driving factor for the decomposition of litter influenced by exogenous nutrient input. In the management of P. massoniana plantations, it was necessary to avoid excessive or single application of nitrogen, and should appropriately apply phosphorus fertilizer based on the soil conditions. This was to enhance soil biological activities and promote litter decomposition and nutrient return.

Effects of nitrogen addition on soil-microbe-extracellular enzyme stoichiometric characteristics in rhizosphere and bulk soil of Larix gmelinii secondary forest

ZHANG Rui, CAI Ruijia, WANG Jingjing, WANG Qinggui, WANG Chuankuan, QUAN Xiankui

2026, 37(2):  453-463.  doi:10.13287/j.1001-9332.202602.016

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Exploring the effects of nitrogen (N) addition on the stoichiometric characteristics of rhizosphere and bulk soil, microorganisms, and extracellular enzymes can provide theoretical insights into the impacts of N deposition on soil carbon dynamics and nutrient limitation status. We conducted a field experiment in a secondary Larix gmelinii forest in the Greater Khingan Mountains to examined the effects of N addition on the stoichiometric characteristics of soil, microorganisms and extracellular enzymes, as well as extracellular enzyme activities. There were four treatments: control (CK), low N (LN), medium N (MN), and high N (HN), with the rate of 0, 25, 50, and 75 kg N·hm^-2·a^-1, respectively. The results showed that N addition significantly increased total soil organic carbon (SOC), total nitrogen (TN), SOC∶TN and SOC∶TP in rhizosphere soil, as well as TN, SOC∶TP and TN∶TP in bulk soil, but significantly decreased total phosphorus (TP) in bulk soil. SOC and SOC∶TN in bulk soil were significantly increased under LN and MN treatments. Nitrogen addition significantly increased microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), MBC∶MBN, MBC∶MBP, and MBN∶MBP in rhizosphere soil. In addition, microbial biomass phosphorus (MBP) in rhizosphere soil, as well as MBC, MBN, MBC∶MBN, MBC∶MBP, and MBN∶MBP in bulk soil significantly increased under LN and MN treatments. Enzyme activities related to carbon, nitrogen, and phosphorus acquisition, and extracellular enzyme nitrogen-to-phosphorus ratio (E_N∶P) in both rhizosphere and bulk soils were enhanced by N addition. Nitrogen addition significantly decreased the extracellular enzyme carbon-to-nitrogen ratio (E_C∶N) and carbon-to-phosphorus ratio (E_C∶P) in rhizosphere soil by 10.9%-17.6% and 7.0%-9.0%, respectively. E_C∶P in bulk soil increased significantly by 7.2%-7.4% under LN and MN treatments. Results of enzyme vector analysis showed that N addition alleviated carbon limitation in rhizosphere microorganisms and phosphorus limitation in bulk soil microorganisms. In rhizosphere soil, E_C∶N showed a linear negative correlation with MBC∶MBN and SOC∶TN, while E_C∶P showed a linear negative correlation with MBC∶MBP and SOC∶TP. In bulk soil, E_C∶P was positively correlated with SOC∶TP and MBC∶MBP. In summary, the stoichiometric characteristics of soil, microorganisms, and extracellular enzymes in rhizosphere and bulk soils responded differently to N addition. Our results would provide a theoretical basis for understanding the rhizosphere effects on forest soil nutrient cycling under N deposition.

Soil microbial diversity and influencing factors of typical vegetations in the dry season of Nanling Mountains, China

GAO Ziyan, ZHUOMA Qucuo, ZHOU Ping, DENG Wangqiu, WANG Mu, YUE Haimei, LI Ting

2026, 37(2):  464-476.  doi:10.13287/j.1001-9332.202601.004

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Soil microorganisms are the most species-rich group in terrestrial ecosystems and serve as crucial bioindicators for assessing soil quality and ecosystem health. We investigated soil microbial community structure and function under dry season five typical vegetation types (ravine evergreen broad-leaved forest, montane evergreen broad-leaved forest, mixed coniferous-broad-leaved forest, montane meadow, montane elfin forest) in Nanling. Utilizing high-throughput sequencing technology, combined with redundancy analysis and Mantel test methods, we explored soil microbial diversity and the influencing factors. The results showed that the phylum Acidobacteria had the highest relative abundance of bacteria, accounting for 40.2%-49.7%, followed by Proteobacteria (28.3%-36.9%) and Actinobacteria (5.9%-8.4%). The relative abundance of Acidobacteria was highest in the montane meadow, while Proteobacteria was most abundant in the ravine evergreen broad-leaved forest. The genus candidatus Solibacter was most prevalent in the montane evergreen broad-leaved forest and lowest in the montane elfin forest. Ascomycota (11.9%-71.9%) and Basidiomycota (19.2%-84.3%) were the dominant fungal groups. Basidiomycota predominated in the ravine evergreen broad-leaved forest and montane evergreen broad-leaved forest, whereas Ascomycota was dominant in the mixed coniferous-broad-leaved forest, montane meadow, and montane elfin forest. At the genus level, Russula was the dominant fungal genus in ravine evergreen broad-leaved forest and montane evergreen broad-leaved forest. Chemoheterotrophy was the primary functional group for bacteria, with an average proportion of 65.3%, being higher in the ravine evergreen broad-leaved forest and montane elfin forest but lower in mixed coniferous-broad-leaved forest. For fungi, symbiotrophic and saprotrophic nutritional modes were the main functional groups, with average proportions of 46.1% and 43.5%, respectively. Symbiotrophic fungi were more abundant in the ravine evergreen broad-leaved forest and montane evergreen broad-leaved forest, while saprotrophic fungi were more prevalent in the mixed coniferous-broad-leaved forest, montane meadow, and montane elfin forest. Soil pH, total nitrogen, and total potassium were the main factors influencing bacterial communities, whereas altitude, ammonium, and nitrate were the primary factors affecting fungal communities. Altitude, ammonium, and total phosphorus were identified as key drivers of the spatial variation in soil microbial diversity under typical vegetation types in the Nanling region during the dry season.

Examining vegetation composition and diversity in rocky desertification regions based on the species-area relationship

FENG Hanhua, YAN Wenjie, WANG Xu, LUO Yong, XU Qihu, ZHENG Quansheng, XIONG Yujiu

2026, 37(2):  477-484.  doi:10.13287/j.1001-9332.202602.002

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Rocky desertification is a major ecological issue in karst regions of China. Scientifically determining the minimum quadrat area for vegetation surveys is crucial for assessing ecological restoration effectiveness. We set up one broad-leaved forest plot and one shrub forest plot in Lechang City, a typical rocky desertification area in nor-thern Guangdong Province. The size of each plot was 100 m×100 m. We conducted community survey and constructed the database of species composition. We used the nested sampling method for secondary sampling statistics of vegetation, and established a species-area curve. The fitting effects of power function, logarithmic function, and logistic model were compared to analyze the relationship between sampling area and species composition and diversity. The results showed that the power function was the best-fitting model (R²>0.996). To include 50%-90% of the species, the minimum required plot areas were 2105-7511 m² for the broad-leaved forest and 2417-7886 m² for the shrub forest, corresponding to side length of 50-90 m. As the area increased, estimated species richness approached the true values more closely, with reduced standard error. Moreover, the relative abundance of dominant species and diversity indices in shrub communities were more sensitive to changes in plot size. For example, the relative abundance of Loropetalum chinense increased markedly from 34% to 54% in the shrubland. The relative abundance of dominant species Castanopsis jucunda in the broad-leaved forest remained stable at around 29% (variation ≤±3%). Given the co-occurrence of vegetation sparsity and patchiness in rocky desertification areas, we recommended that sampling plot size should be rationally set based on community type and research objectives in vegetation surveys to improve sampling representativeness and assessment accuracy.

Variation and coordination of non-structural carbohydrate among organs of major woody plants in forest-grass ecotones of northern Hebei, China

WANG Rui, LIU Jinhua, LI Chenghao, WANG Xumin, ZHAO Shuai-ming, XU Xuehua

2026, 37(2):  485-493.  doi:10.13287/j.1001-9332.202602.003

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To elucidate the variation patterns and coordinated effects of non-structural carbohydrate (NSC) and their components across tree species and organs, we investigated Quercus mongolica, Malus baccata, and Ulmus pumila on different slope aspects (north, northwest, south, southwest slope) in the forest-grassland ecotone of northern Hebei Province. We examined the contents of soluble sugar, starch, and NSC in fine roots, branches, and leaves across slope aspects, to reveal the intra- and inter-specific variations and their driving factors. The results showed that the NSC and its component contents in all organs of the three tree species exhibited inconsistent variation patterns across the slope aspects. The NSC content in all organs of Q. mongolica ranged from 26.52 to 83.98 mg·g^-1 across slope aspects, while it ranged from 54.17 to 91.56 mg·g^-1 for M. baccata and 28.94 to 152.78 mg·g^-1 for U. pumila. Across all organs of the three tree species, the leaves of U. pumila exhibited the highest content of NSC and components. In contrast, Q. mongolica displayed the lowest levels in all organs, with the exception of a relatively higher soluble sugar content in fine roots. Both slope aspect and tree species significantly influenced organ NSC content. The intra-specific variation coefficients of NSC in different organs were relatively small. The inter-specific variation coefficients showed no significant differences among organs. Significant coordinated relationships were observed in NSC component contents among organs. There were positive relations for soluble sugar content between fine roots and branches. The soluble sugar content and starch content between fine roots and leaves exhibited significantly negative correlation. Redundancy analysis indicated that soil water content and pH were the primary environmental factors influencing the contents of NSC and its components in fine roots, branches, and lea-ves of the three tree species. Q. mongolica and M. baccata exhibited conservative strategy, while U. pumila exhibited acquisitive strategy.

Effects of straw returning and nitrogen application rate on photosynthesis and fluorescence characteristics in flag leaves and grain yield of wheat in dryland

WANG Pengbo, ZHANG Wenjing, QIAO Changchang, TANG Yizhe, YANG Yingcong, HUANG Ming, XU Guowei, WANG Hezheng

2026, 37(2):  494-502.  doi:10.13287/j.1001-9332.202602.011

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We examined the effects of straw returning and nitrogen application rates on the photosynthetic and fluorescence characteristics in flag leaves and grain yield of wheat (Luohan 22) in drylands, with an experiment following split-plot design. The main plot treatments were straw returning, namely S₀(no straw returning) and S₁(total straw returning with the amount of 9000 kg·hm^-2). The subplot treatments were five nitrogen application rates of 0, 120, 180, 240, and 300 kg·hm^-2, represented by N₀, N₁, N₂, N₃, and N₄ respectively. We measured the photosynthetic and chlorophyll fluorescence parameters in flag leaves at 0, 7, 14, 21, and 28 days after flowering, as well as the final yield and yield components. The results showed that net photosynthetic rate, transpiration rate, stomatal conductance, and photochemical quenching of all treatments showed a decreasing trend with growth period progressing. The maximum photochemical quantum yield and electron transport rate first increased and then decreased with the growth process, peaking at 7 and 14 days after flowering, respectively. The non-photochemical quenching coefficient showed an increasing trend as the growth period progressing. At each nitrogen application level, net photosynthetic rate, transpiration rate, stomatal conductance, photochemical quenching, maximum photochemical quantum yield, and electron transport rate at each measurement period were all higher in S₁ than in S₀. Under the same straw returning treatment, these parameters first increased and then decreased with increasing nitrogen application rate, with the highest value in N₃. Compared with S₀N₃, the indicators of S₁N₃ increased by 4.3%, 6.1%, 2.6%, 5.9%, 3.9% and 11.0%, respectively. The non-photochemical quenching coefficient was higher in S₀ than in S₁ at the same nitrogen application rate. Under the same straw returning conditions, it first decreased and then increased with increasing nitrogen application rates, with the highest value in N₀. The non-photochemical quenching coefficient in S₁N₃ was 4.1% lower than that in S₀N₃. The effective panicle numbers, grains per panicle, 1000-grain weight, and yield of wheat were all higher in S₁ than in S₀ under the same nitrogen application rate. Under the same straw returning treatment, these parameters first increased and then decreased with increasing nitrogen application rates. Among all the treatments, S₁N₃ gained the highest spike numbers, grains per panicle, 1000-grain weight, and yield, which was 2.1%, 2.7%, 3.9%, and 5.2% higher than that under S₀N₃, respectively. Similarly, the economic benefit and cost-benefit ratio reached their highest in S₁N₃, at 12629 yuan·hm^-2 and 198.1% respectively, both being 8.0% higher than S₀N₃. Therefore, straw returning combined with nitrogen application rate at 240 kg·hm^-2 is a suitable cultivation practice for dryland wheat in the western Henan Province and regions with the same conditions.

Effects of sowing method and row spacing configuration on photosynthetic matter production and yield formation of wheat

YANG Minghao, GE Juqing, SHI Yu, YU Zhenwen, ZHANG Yongli, ZHANG Zhen

2026, 37(2):  503-510.  doi:10.13287/j.1001-9332.202602.015

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We explored the physiological mechanisms underlying the effects of sowing method and row spacing configuration on photosynthetic substance production and yield formation in wheat (‘Jimai 22’ variety) with a two-factor split-plot experiment. The main plots consisted of sowing method: wide precision sowing (K) and conventional strip sowing (T), while the subplots consisted of row spacing: 20 cm (R1), 25 cm (R2), and 30 cm (R3), resulting in six treatments. We measured flag leaf photosynthetic characteristics, senescence traits, and ¹³C assimilate accumulation and distribution under various sowing method and row spacing configurations. The results showed that KR2 treatment significantly increased SPAD values, net photosynthetic rate, transpiration rate, stomatal conduc-tance, superoxide dismutase activity, and soluble protein content in the flag leaf at 14, 21, and 28 days after flower-ing, with average increase of 23.8%, 16.3%, 16.8%, 15.6%, 14.4%, and 15.2%, respectively. It significantly reduced intercellular CO₂ concentration and malondialdehyde content by 11.9% and 12.1%, respectively. In addition, the KR2 treatment promoted the transport of ¹³C assimilates from stems and leaves to grains, and significantly increased yields by 17.5%, 10.7%, 24.9%, 10.1%, and 23.6% when compared with those in the KR1, KR3, TR1, TR2, and TR3 treatments, respectively. In summary, the 25 cm row spacing wide precision sowing method significantly improved photosynthetic characteristics of the flag leaf during the mid-to-late grain filling stage of wheat, delayed leaf senescence, and promoted allocation of photosynthetic products to grain, thereby achieving the highest yield.

Effects of different types of biochar on phosphorus and stoichiometric characteristics of extracellular enzymes in paddy soil

FAN Xiaoge, ZHANG Ruiqing, LIU Wenbo, FANG Jun, CUI Xin, CHAI Yanjun, ZHANG Min, SHAN Shengdao

2026, 37(2):  511-520.  doi:10.13287/j.1001-9332.202602.012

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Understanding the stoichiometric characteristics of phosphorus and extracellular enzyme activity in paddy soil under the application of different types of biochar can improve phosphorus management and nutrient utilization efficiency. A two-year field experiment was conducted with treatments including no fertilization (CK), chemical fertilizer (NPK), and biochar amendments based on NPK: perishable organic waste biochar (WB), rice straw biochar (SB), and pig manure biochar (MB). Combined with enzyme vector analysis, we explored the effects of different biochar types on soil phosphorus availability and microbial carbon, nitrogen, and phosphorus-related enzyme activities. Results showed that the NPK treatment increased total phosphorus, available phosphorus, and crop yield by 39.8%-73.1%, 128.5%-131.0%, and 27.0%-33.9%, respectively. Compared to NPK, all three biochar treatments consistently elevated soil total phosphorus, with MB>WB>SB, where MB significantly increased by 108.8% and 156.0%. The MB treatment enhanced soil available phosphorus and phosphorus activation capacity by 297.1%-388.4% and 53.3%-143.1%, respectively, leading to average annual improvements of 12.1% in rice yield and phosphorus use efficiency. Biochar application boosted β-glucosidase (BG), N-acetyl-β-glucosaminidase (NAG), and leucine aminopeptidase (LAP) activities by 43.9%-90.4%, 15.7%-77.6%, and 84.5%-173.4%, respectively, but inhibited alkaline phosphatase (ALP) activity by 41.8%-54.9%. Soil enzyme carbon-phosphorus ratios in biochar treatments were significantly higher than in NPK, while carbon-nitrogen ratios were lower. Biochar application effectively alleviated microbial phosphorus limitation and may have shifted to nitrogen limitation. There were significant positive associations between soil total phosphorus and available phosphorus with BG, LAP activity, rice yield, and phosphorus use efficiency, but negative associations with ALP activity. In summary, biochar application enhances soil phosphorus availability and extracellular enzyme activity, mitigated microbial phosphorus limitation, an increased rice yield. The MB performed the best.

Spatiotemporal variations and influencing factors of cultivated land utilization efficiency in Shanxi Pro-vince, China under the concept of green and low-carbon development

FU Jianxin, JIANG Min, WU Zhiping, LI Ruiyu, HAN Maya, LIU Geng

2026, 37(2):  521-529.  doi:10.13287/j.1001-9332.202602.024

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To investigate the efficiency of utilization of cultivated land (E_GLU) and its influencing factors in Shanxi Province under the context of carbon neutrality, we established a comprehensive evaluation index system from three dimensions: input, expected output, and unexpected output. We employed the super-efficiency model to measure the E_GLU, applied kernel density estimation and spatial autocorrelation analysis to examine the spatiotemporal variations, and used a Tobit regression model to identify the key influencing factors. The results showed that the E_GLU in Shanxi Province exhibited a generally fluctuating upward trend from 2008 to 2022, which increased from 1.11 to 1.19. Among the regions, the southern part of Shanxi experienced the highest annual average growth rate (0.077), while the northern part recorded the lowest (0.072). The trend surface fitting curve of E_GLU shifted from an east-higher-west-lower pattern in 2008 to a west-higher-east-lower configuration by 2022. The difference between nor-thern and southern regions had gradually narrowed, while the pattern of regional differentiation was highly evident. Panel Tobit regression analysis revealed that the fertilizer application rate per unit cultivated land area and total agricultural machinery power exhibited significant negative correlation with E_GLU, while the multiple cropping index, crop planting structure, and per capita cultivated land area showed a significant positive correlation with E_GLU. The correlation between the irrigation index and E_GLU presented a negative-to-positive change pattern, whereas per capita disposable income of rural residents exhibited a relatively weak correlation with E_GLU. Our findings would provide a reference for formulating effective green and low-carbon utilization policies for cultivated land and promoting sustainable cultivated land development in Shanxi Province.

Relationship between gully density and characteristics of watershed channel network in typical black soil region in Northeast China

GUO Haiyan, ZHANG Yan, LI Kunheng, XING Huimiao, LI Xinmeng

2026, 37(2):  530-538.  doi:10.13287/j.1001-9332.202602.014

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We selected sixty-four survey units in the typical black soil (soil sub-class) distribution area of Northeast China, including 32 complete small watersheds and 32 non-closure small watersheds. All gullies were identified through high-resolution image visual interpretation. The Strahler stream order method was used to classify the gullies. We calculated the parameters such as small watershed characteristics, gully density (line and area density of gullies), and gully network characteristics. By analyzing the relationship between gully density and watershed characteristics, gully network evolution, and fractal dimensions, we explored the activity level and developmental potential of gullies in the black soil region. The results showed the line density of gullies in the surveyed watersheds ranged from 0.60 to 11.45 km·km^-2, with an average of 2.09 km·km^-2, and 35.9% exceeded moderate erosion levels. The area density of gullies ranged from 7136 to 160323 m²·km^-2, with an average of 31752 m²·km^-2. The highest gully order in small watersheds reached level 8, with 1662 first-order gullies accounting for 67.8%. The fractal dimension fitting curve of the network exhibited linear patterns, indicating significant fractal characteristics in the gully network. The tributary development was higher in the central and southern parts of the typical black soil distribution area, with greater complexity in the gully network. All surveyed watersheds were in the juvenile stage of gully development and were in an accelerated growth phase. There were no significant differences in gully density and gully network characteristics between the two types of small watersheds. Gully line density showed significant correlations with average watershed slope, shape coefficient, maximum gully order, and network fractal dimension, but no significant correlation with survey unit area. These findings would help clarify the spatial variation and deve-lopmental potential of gully density, providing a theoretical basis for gully erosion investigation and prevention in black soil regions.

Thermal environment effects of residential areas based on visual indices in summer sunny days: A case study in Tongshan District, Xuzhou City, China

ZHOU Hongxuan, SONG Kaichen, SUN Xi, SUN Jing, LI Sha

2026, 37(2):  539-550.  doi:10.13287/j.1001-9332.202602.025

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The thermal environment in residential areas is closely related to the thermal comfort and safety of residents. With Tongshan District in Xuzhou City as a case, we explored the influencing patterns and potential mechanisms of residential compositions (quantified by visual indices) on the thermal environment parameters (air tempera-ture, relative humidity, and thermal-humidity index) at different periods in sunny summer days. The results showed that residential compositions were associated with the thermal environment parameters, and that the composition of residential areas influenced thermal environments by affecting energy flow. In the forenoon, residential compositions primarily regulated the thermal environment through ventilation. The construction view index (VI_C) showed a reduction in cooling. The green view index (VI_G) exhibited reductions in cooling and humidification. The sky view index (VI_S) showed an increase in cooling, respectively. VI_C and VI_S contributed 9.9% and 26.4% independent effects to the air temperature between the residential areas, and 10.0% and 8.7% to the relative humidity, respectively. Meanwhile, VI_S contributed a 20.2% independent effect to the temperature-humidity index. In the afternoon, heat released from constructions and vegetation evapotranspiration dominated the thermal environment, contributing 13.5% and 15.3% independent effects to the air temperature differences among the residential areas, 8.8% and 17.8% to the relative humidity, and 10.8% and 8.3% to the temperature-humidity index, respectively. Further analysis showed that VI_C∈(0.13, 0.14), VI_G∈[0, 0.15)∪(0.45, 1] and VI_S∈[0, 0.04)∪(0.24, 1] could effectively improve the thermal environment. Our results could provide quantitative references for residential area design.

Identification and evaluation of cold source risk organisms in close areas of a coastal nuclear power plant

HU Xinyue, CUI Meng, JIN Yuan, LIU Guize, SONG Changchun, ZHANG Yunlei

2026, 37(2):  551-562.  doi:10.13287/j.1001-9332.202602.031

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Species invasion in marine has increased the frequency of security incidents at coastal nuclear power plants, posing serious threats to the cooling water intake. To systematically identify the risk organisms in nuclear power cooling water sources and clarify their distribution pattern, we established a risk identification and assessment framework for marine organisms in cooling water intake areas. Based on field investigation conducted in the summer of 2024 in the adjacent waters of a nuclear power plant in northern China, we categorized marine organisms into five types: phytoplankton, zooplankton, swimming animals, benthic animals, and selected intertidal organisms. Trophic level, habitat layer, body size, body length, and density were used as evaluation criteria. These indices were combined with type-specific traits (e.g., migratory behavior and reproduction mode) to develop a scoring system, with each indicator being assigned a maximum score of 10 points. Scores were determined based on the potential risk of each biological trait to clogging the water intake, and a spatial weight based on the distance from sampling points to the intake was incorporated to calculate the total risk score for each species. We classified risk levels into low, medium, and high according to thresholds set at 30% and 80% of the total possible score. Results showed that a total of 40 phytoplankton, 28 zooplankton, 27 swimming animals, 62 benthic animals, and 43 intertidal species were recorded. Through multi-indicator integration and spatial weighting analysis-balancing field data authenticity and theoretical traits of species, Loligo sp., Charybdis japonica, and Konosirus punctatus were identified as high-risk species. Moreover, there was a higher density of high-risk organisms in the northern area near the water intake. By integrating functional traits and measured data into a comprehensive evaluation framework, this study could provide a scientific basis for risk organism identification, early warning, and the development of prevention and control strategies for cooling water systems near nuclear power plants.

Ecological restoration path of territorial space in the Guangdong-Hong Kong-Macao Greater Bay Area, China

ZHU Jinli, ZHAO Qing, LUO Hao, ZHANG Chi

2026, 37(2):  563-571.  doi:10.13287/j.1001-9332.202602.023

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The Guangdong-Hong Kong-Macao Greater Bay Area (GBA) is one of China’s largest urban agglomera-tions in terms of economic aggregate. However, accelerated urbanization have led to a series of ecological problems, including ecosystem fragmentation and imbalances in ecosystem functions. The precise identification and optimization of key ecological restoration areas are critical pathways for conducting territorial spatial ecological restoration, holding significant value for safeguarding the ecological security of the GBA. We integrated the MSPA-InVEST model with circuit theory to assess habitat quality of GBA and construct an ecological network, with which we identified key regions for ecological restoration. Based on the findings, we proposed optimization strategies for territorial spatial ecological restoration in the GBA. The results showed that the average habitat quality value across the GBA was 0.69 in 2023, indicating an overall favorable level of habitat quality. Extremely high-quality habitat areas covered 26431.8 km², while extremely low-quality habitat areas spanned 8662.9 km². By integrating ecological network construction and habitat quality assessment, we identified 41 ecological source optimization zones (total area: 742.8 km²), 151 ecological pinch point improvement zones (total area: 12.4 km²), and 499 ecological barrier restoration zones (total area: 158.5 km²). We proposed targeted measures for territorial spatial ecological restoration in the GBA, including structural optimization of ecological source, functional enhancement of ecological pinch point, and systematic restoration of ecological barrier areas at the regional-plot level. Our results would provide a scientific basis and practical guidance for territorial spatial ecological restoration in the GBA.

Habitat network construction in Elephas maximus activity areas

XIE Zihao, WEI Wen, LUO Weixiong

2026, 37(2):  572-582.  doi:10.13287/j.1001-9332.202602.032

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Under the ongoing strategic advancement of biodiversity conservation, the delineation of the proposed Asian Elephant National Park progressively entered the phase of spatial identification. Identifying the habitat network of regional flagship and umbrella species served as a critical prerequisite and scientific basis for defining spatial extent of the park. This study focused on the key distribution areas of Asian elephants (Elephas maximus) in Xishuangbanna, Pu’er, and Lincang. We integrated the InVEST model with morphological spatial pattern analysis (MSPA) to identify habitat sources, selected six ecological resistance factors and determined their weights using the entropy weight method to construct a resistance surface. We applied the Linkage Mapper tool to extract habitat corridors, ecological barrier points and pinch points, thereby building the habitat network for Asian elephant acti-vity areas. The results showed that a total of 158 habitat sources were identified, covering approximately 23000 km², with primary and secondary sources together accounting for 18000 km²(20.5% of the study area). There was a spatial pattern of “high density in the central region, sparse distribution at both ends, and north-south connecti-vity”, forming a continuous and ecologically valuable core habitat source areas along the Xishuangbanna-Pu’er boundary. We extracted 439 habitat corridors with a combined length of 4616.58 km, which displayed a pattern of “denser in the south, sparser in the north, connecting patches, and forming corridor belts”, and effectively supported regional-scale elephant movement. The ecological barrier points in Asian elephant migration paths are predominantly distributed in areas of dense road disturbance and fragmented habitats in Lincang City and central-eastern Pu’er. The ecological pinch points are mainly concentrated in Menghai County and the Menglun area of Xishuangbanna Prefecture, as well as in central-southern Pu’er. Clarifying the differentiated management needs corresponding to various source areas within the core zones of Asian elephants and prioritizing the protection of highly sensitive regions such as ecological barriers and ecological pinch points could enhance the overall connectivity and stability of the regional habitat network, thereby expanding its umbrella effect on biodiversity conservation.

Effects of landscape pattern on the damage of pine wilt disease in the head region of the Three Gorges Reservoir

FU Yanrong, ZENG Yu, WU Yu, REN Shun, LIU Jianming, GU Jian, PENG Gangzhi

2026, 37(2):  583-590.  doi:10.13287/j.1001-9332.202602.028

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The spread of pine wilt disease (PWD) is related to the spatial heterogeneity of the landscape within the affected area. Investigating the effects of landscape patterns on PWD severity can facilitate the construction of landscape ecological security patterns and contribute to long-term regional prevention and control strategies. Based on unmanned aerial vehicle (UAV) remote sensing data and forest resource inventory data, we adopted correlation analysis method and hierarchical segmentation in the linear mixed-effects model to evaluate the impacts of landscape patterns on PWD at both landscape and patch levels in the head region of the Three Gorges Reservoir. The results showed that larger patch sizes and higher landscape fragmentation were associated with lower PWD severity at the landscape level. Area characteristics and aggregation explained 45.9% and 29.3% of the variation in disease den-sity, respectively. At the patch level, the fragmentation of pure pine forest (host) patches was significantly positively correlated with disease density, while more regular patch shapes were associated with greater PWD severity. The area and connectivity of native dominant forest (non-host) patches were significantly positively correlated with disease density. The aggregation and connectivity of farmland and water (non-host) patches were significantly negatively correlated with the disease density. Therefore, fine-scale patch classification and integrated consideration of the landscape ecological processes in different patches would be crucial for accurately understanding the occurrence and spread of the PWD.

Research progresses on the effects of rice cultivation on amelioration of saline-alkali soil

TANG Haijiang, GUO Fucheng, YANG Jiuju, XIAO Donghao, LIAO Tinglu, LUO Chengke

2026, 37(2):  591-600.  doi:10.13287/j.1001-9332.202602.017

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Saline-alkali soils pose severe challenges to agricultural production and the sustainable utilization of land resources. Efficient amelioration and utilization of saline-alkali land is of great significance for expanding agricultural production and safeguarding national food security. Rice cultivation is an important approach to ameliorate saline-alkali soils, offering dual benefits in ecological improvement and economic development. We reviewed research on improving saline-alkali land through rice cultivation over the past two decades. Long-term (≥5 years) rice cultivation exerts positive effects on saline-alkali soils. Specifically, soil pH and electrical conductivity decreased by 5.9%-23.0% and 22.1%-89.7%, respectively. Soil organic matter, alkali-hydrolyzable nitrogen, available phosphorus, and available potassium contents increased significantly by 60.0%-66.7%, 90.2%-131.0%, 68.9%-89.2%, and 6.7%-179.2%, respectively. In addition, the richness (Ace index) of soil bacterial and fungal communities increased by 10.5%-23.4% and 23.8%-52.8%, and the Shannon index increased by 60.9%-98.7% and 18.3%-107.0%, respectively. Improvements in the physicochemical and biological properties of saline-alkali soils enhanced rice yield and yield components, with thousand-grain weight, grains per panicle, and overall grain yield be increased by 10.1%-17.2%, 9.3%-46.6%, and 48.2%-91.1%, respectively. Future research should focus on innovations in salt-alkali tolerant rice germplasm resources and variety breeding, rhizosphere microbial remediation strategies for salt-alkali tolerant rice, carbon sequestration potential assessment systems for saline-alkali paddy fields, and diversified development approaches. These efforts would provide a reference for deeply exploring the comprehensive utilization potential of saline-alkali land and advancing the sustainable use and efficient remediation.

Carbon sequestration efficiency of straw incorporation: Long-term dynamics, influencing factors and efficiency-enhancing approaches

WANG Sichu, SUN Guofeng, SUN Renhua, XU Zhiyu, ZHOU Wei, SHENG Jing

2026, 37(2):  601-608.  doi:10.13287/j.1001-9332.202602.013

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Straw returning is a key measure to increase soil carbon sequestration. We reviewed the critical processes of straw carbon sequestration, the long-term dynamics of carbon sequestration efficiency, influencing factors, and enhancement pathways. The short-term effects of straw returning include the increase in active organic carbon components such as dissolved organic carbon, particulate organic carbon, and microbial biomass carbon. The long-term effect is the accumulation of total organic carbon reserves. Soil carbon storage after straw returning follows a progressive saturation pattern, with lower initial soil organic carbon content allowing greater carbon storage potential and requiring more time to reach saturation. The efficiency of straw carbon sequestration is constrained by straw returning methods, straw characteristics (crop type, lignin content, straw size, and return quantity), as well as soil and climatic conditions. Enhancement pathways for straw carbon sequestration include optimizing straw return methods, water-saving irrigation, balanced fertilization, microbial inoculation, and diversified cropping systems. Future research should focus on long-term dynamic monitoring of straw carbon sequestration, coordinated optimization of agronomic measures, and adaptive management to climate change.

Research advances in soil microbial carbon use efficiency in response to climate change

DANG Jianyu, MA Xiaojian, YANG Xinyi, PAN Yuliang, HE Xunyang, WANG Kelin, LI Dejun, DUAN Pengpeng

2026, 37(2):  609-621.  doi:10.13287/j.1001-9332.202602.035

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Soil microbial carbon use efficiency (CUE), defined as the proportion of assimilated carbon allocated to microbial growth versus maintenance, is a key parameter regulating terrestrial soil organic carbon (SOC) storage. The response of CUE to climate change and its feedbacks profoundly affect global carbon cycle and soil carbon sequestration. At present, there are substantial uncertainties regarding the mechanisms underlying the responses of CUE to climate change and the ecological consequences. We synthesized research progress on soil microbial CUE over the past 20 years. First, we clarified the basic concept and computational approaches of CUE, and compared the principles, strengths, and limitations of three mainstream measurement techniques (isotope labeling method, stoichiometric model, and thermodynamic efficiency method). Second, we summarized the key biotic and abiotic factors influencing CUE. Focused on the mechanisms underlying the main and interactive effects of elevated atmospheric CO₂ concentration, climate warming, and altered precipitation patterns on microbial CUE, and based on a “resource-cost trade-off” framework, we discussed the potential mechanisms underlying the heterogeneous responses of CUE across different ecosystems, and summarized the bottlenecks and challenges that still existed in current research regarding methodological standardization, the analysis of deep soil processes, the quantification of multi-factor interaction effects, and the application of CUE in earth system models (ESMs). We proposed an integrative research framework spanning from micro-scale metabolic mechanisms to macro-scale carbon cycling patterns, emphasizing the need for methodological innovation, multi-scale networked observations, and model-experiment integration, to thoroughly reveal the dynamics and adaptive mechanisms of CUE under climate change.

Research progress on the feasibility of carbonization treatment for addressing plastic residual pollution

ZHA Jingjie, MA Xuechun, ZHANG Jiajia, ZHAO Meng, HE Wentian, ZOU Guoyuan, LIU Weijuan, CHEN Yanhua

2026, 37(2):  622-634.  doi:10.13287/j.1001-9332.202602.034

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Microplastics are formed during the degradation of plastic products under the action of environmental factors such as light, high temperature and mechanical friction, which are widely used in agricultural production. These microplastics would threaten human health through the accumulation of the food chain, which has become a global pollution problem. Traditional plastic waste disposal methods (landfilling, incineration, mechanical recycling) have obvious limitations in both environmental benefits and economic feasibility. In contrast, emerging plastic carbonization technology holds potential for achieving harmless transformation of pollutants and resource utilization. Through techniques like co-thermal decomposition, hydrothermal carbonization, and catalytic carbonization, plastics can be synergistically converted into high-value carbon materials (biochar, hydrothermal carbon, and carbon nanomaterials), effectively reducing plastic pollution. These materials also exhibit promising applications in microplastic adsorption, soil remediation, and integrated pollutant treatment of pollutants. However, challenges including unclear reaction mechanisms, inconsistent product properties, high energy consumption, scalability difficulties, and a lack of policy support, hinder industrial application and the development of value-added products. We reviewed the mechanisms, application scenarios, and limitations of three plastic carbonization technologies, including co-thermal decomposition, hydrothermal carbonization, and catalytic carbonization. Future efforts should integrate life cycle assessment and multi-technology strategies to further validate their environmental and economic sustainability, facilitating the transition from theory to practice.

Research progress on marine ecological disasters and disaster prevention and mitigation

AN Xinlong, WANG Qiuzhen, GU Jiguang, LI Xuemei, WANG Chen

2026, 37(2):  635-646.  doi:10.13287/j.1001-9332.202602.033

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Ecological disasters pose severe threats to marine ecosystems and the marine economy, and therefore disaster prevention and mitigation efforts are critically important. We reviewed the occurrence, impacts, and related research progress in disaster prevention and mitigation of marine ecological disasters, including harmful algal blooms, jellyfish blooms, starfish blooms, marine biofouling, and marine biological invasions. Marine ecological disasters exhibit diverse types, where the occurrence of one type may trigger others and even lead to the emergence of new disaster-causing organisms. In the face of complex marine ecological environmental changes, monitoring, early warning, and prevention technologies for marine ecological disasters must evolve with the times. The fundamental principles of “prevention first, combining prevention and control, rational utilization, and effective management” are essential for effectively preventing and mitigating marine ecological disasters. To minimize disaster losses, future efforts should focus on strengthening researches into the interrelated mechanisms of marine ecological disasters, monitoring and early warning systems, effective prevention and control technologies, and the resource utilization of disaster-causing organisms.