Table of Content

18 November 2025, Volume 36 Issue 11

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Academician's Viewpoint

A harmonious ecosystem management paradigm based on modernized perception methods

MA Keming

2025, 36(11):  3231-3236.  doi:10.13287/j.1001-9332.202511.033

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Realizing a modernization of harmonious coexistence between humans and nature is the core content of current ecological civilization construction. Ecology is an important scientific foundation for ecological civilization construction. It is urgent to explore new ways to enhance the perception and regulation of nature, which would contribute new theories and methods to the modernization of harmonious coexistence between humans and nature. By fully leveraging modern technology to empower human senses, ecology is rapidly expanding in the form of modernized perception methods, providing several new ways for humans to deeply perceive nature and gradually achieving the modernization of the discipline's development. Under such a background, I argued that ecology should change the current adaptive ecosystem management paradigm that starts from nature conservation and establish a new scientific method system to conduct more precise mutual feedback regulation of the relationship between humans and nature. I proposed a harmonious ecosystem management paradigm that starts from human sensory satisfaction, takes ecosystem services as the link, comprehensively considers supply and demand balance and input-output, and fully cross-links various human sensory experiences with various ecosystem services to precisely regulate the harmonious relationship between humans and nature. The establishment of this new paradigm depends on how modern techno-logy promotes the future development of ecology, requires interdisciplinary integration from natural science to social science, and relies on extensive practice by government departments.

Original Articles

Effect of meteorological droughts in different seasons on the radial growth of Abies recurvata

ZHANG Xingzi, WANG Bingxin, GUO Mingming

2025, 36(11):  3237-3244.  doi:10.13287/j.1001-9332.202511.008

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To investigate the impact of meteorological droughts in different seasons on tree radial growth, we analyzed the correlations between radial growth of Abies recurvata at three altitudes (3400, 3800, 4000 m) and clima-tic factors along with resistance, recovery, and resilience to different seasonal droughts (spring 1998, summer 2008, consecutive spring-summer 2003) in Miyaluo of Sichuan, utilizing tree-ring width index and standard chronology. The results showed that at low altitude (3400 m), chronologies showed significant positive correlation with Palmer drought severity index (PDSI) from previous September to current June, and significant negative correlation with current January monthly mean maximum temperature. At middle and high altitudes (3800, 4000 m), significant positive correlation occurred with current April PDSI and precipitation. The resistance of radial growth at three altitudes to consecutive spring-summer drought and spring drought was significantly lower than that to summer drought, while the resilience to consecutive spring-summer drought at middle and high altitudes (0.95, 0.94) was significantly lower than that to spring drought (1.13, 1.23) and that to summer drought (1.17, 0.99). Under consecutive spring-summer drought, the resistance at low altitude (0.57) was significantly lower than that at high altitude (0.78), the recovery and resilience were significantly higher than those at high altitude, and the resistance at middle altitude was significantly lower than at high altitude. Under spring drought, the resistance and resilience at low and middle altitudes were significantly lower than at high altitude. Under summer drought, the recovery and resilience at low and high altitudes were significantly lower than at middle altitude. In summary, the radial growth of A. recurvata was most severely impacted by consecutive spring-summer drought. Populations at low altitudes demonstrated significantly weaker resistance, while those at high altitudes were limited by reduced recovery capacity, leading to lower growth resilience compared to low-altitude populations.

Effect of UAV-LiDAR point density on aboveground biomass estimation in Larix olgensis plantations

DING Jingyu, LIU Xin, DONG Lihu, HAO Yuanshuo

2025, 36(11):  3245-3255.  doi:10.13287/j.1001-9332.202511.003

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Accurate estimation of plantation biomass is of great significance for the scientific management and opera-tion of forests and for supporting China's “Dual Carbon” goals. Traditional ground survey methods have bottlenecks such as low efficiency and limited coverage. Unmanned aerial vehicle LiDAR (UAV-LiDAR) technology provides a new approach for forest aboveground biomass estimation through high-precision 3D point data. We selected 112 permanent plots of Larix olgensis plantations in Mengjiagang Forest Farm and classified them into a density gradient of nine levels from 200 to 0.5 points·m^-2. We established a forest aboveground biomass estimation model by generating subsets through repeated random pulse sampling and extracting canopy mean height (HMEAN) and canopy height ratio (CHR), and analyzed the effects of point density on indicator stability, model parameters, and prediction accuracy. The results showed that when point density decreased from 200 points·m^-2 to 0.5 points·m^-2, the mean values of HMEAN and CHR remained highly stable, but the random errors from repeated sampling increased. The mean standard deviation of HMEAN increased from 0.012 m to 0.261 m, and that of CHR increased from 0.0008 to 0.0167. The density reduction caused structural shifts in the aboveground biomass model, along with gradually expanding uncertainty in model parameters. The predictive accuracy metrics, root mean square error (RMSE), and Bias progressively increased, while the standard deviations of repeated sampling for both RMSE and Bias also showed a gradually expanding trend. The predicted mean aboveground biomass for the 112 plots remained stable, but the standard deviation of repeated predictions increased from 0.26 Mg·hm^-2 to 5.26 Mg·hm^-2. Reducing point density significantly decreased the accuracy and stability of aboveground biomass estimation. Maintaining point density above 20 points·m^-2 could control the RMSE within 16%. This study provided a valuable reference for UAV-LiDAR data acquisition and aboveground biomass estimation in L. olgensis planation.

Effects of soil warming on fine root stoichiometry of Castanopsis kawakamii natural forest in mid-subtropical zone

HUANG Jinxue, WU Fan, LIANG Tianhao, FU Hejing, JING Chenhong, YANG Zhijie, XIONG Decheng

2025, 36(11):  3256-3264.  doi:10.13287/j.1001-9332.202511.001

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We conducted an in-situ soil warming (0, +4 ℃) experiment in Samming, Fujian Province to investigate the effects of soil warming on the contents of carbon (C), nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and stoichiometry in absorptive and transport roots of Castanopsis kawakamii natural forest during the rainy season (May) and dry season (November). Roots were collected using the in-growth core method. The results showed that in the rainy season, warming did not alter the contents of C, N, P, K, Ca, Mg, and the N/P in either absorptive roots or transport roots, while C/N in transport roots and Ca/Mg in absorptive roots increased by 40.0% and 82.7%, respectively. In the dry season, warming reduced C, N, P and K contents of absorptive roots by 10.8%, 34.8%, 37.3%, 58.8%, respectively; increased the C/P by 43.8%; reduced C, N, P and Mg contents in transport roots by 4.2%, 27.0%, 28.7%, 20.0%, respectively; and increased C/N by 30.0%. However, there were no significant changes in Ca content, N/P, and Ca/Mg in either absorptive or transport roots. Collectively, warming had a greater impact on the stoichiometric traits of fine roots in the dry season than in the rainy season. In the rainy season, both the control and warming treatments exhibited P limitation or N and P co-limi-tation. In the dry season, both treatments were primarily N-limited. Moreover, there was a significant negative correlation between K and Ca in absorptive roots and transport roots in warming treatment. There was a significant positive correlation between C, N, C/P of absorptive roots and soil temperature and moisture. Fine roots could maintain stable nutrient absorption following warming in the rainy season, while warming could affect absorption of major nutrient elements in the dry season. Warming did not change nutrient limitation status of natural forest, but significantly affected the stoichiometric characteristics of fine roots by altering soil temperature and moisture.

Effect of drought on soil microbial carbon utilization efficiency of rhizosphere in moso bamboo forests

MAO Yilian, GE Xiaogai, XUE Xupeng, XU Rong, WANG Xiaoming, ZHOU Benzhi

2025, 36(11):  3265-3276.  doi:10.13287/j.1001-9332.202510.010

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Clarifying the impact of drought on soil microbial composition and carbon utilization efficiency (CUE) would help reveal the mechanisms underlying its effects on soil microbial structure and function in moso bamboo forest. We examined the chemical properties, enzyme activities, microbial community structure and diversity of soil rhizosphere of moso bamboo in response to simulated drought from 2019 to 2023, and calculated the CUE of rhizosphere soil microorganisms to clarify the impact of drought on rhizosphere soil microbial CUE. The results showed that drought significantly reduced soil pH by 4.8%, total nitrogen by 33.5%, available nitrogen by 38.2%, available phosphorus by 33.0%, and cation exchange capacity by 24.6% on 2-year-old moso bamboo. Under the drought treatment, soil organic carbon in 2-year-old and 4-year-old moso bamboo was significantly decreased by 38.6% and 28.4%, respectively, while easily oxidizable organic carbon in 3-year-old moso bamboo was increased by 21.6%. The response of rhizosphere soil enzyme activity to drought varied with the age of bamboo. β-glucosidase activity of 1- to 4-year-old moso bamboo significantly decreased by 54.0%-78.1%, whereas the leucine aminopeptidase activities of 1-year-old moso bamboo increased by 40.7%. The acid phosphatase activity decreased significantly by 24.2% and 35.6% in 1- and 3-year-old bamboos, respectively, while that of 2-year-old bamboo increased by 44.2%. Drought significantly reduced microbial biomass carbon in the rhizosphere soil of bamboo across all age groups, with the most pronounced decrease being observed in 1-year-old group (46.3%). Soil microbial biomass nitrogen decreased by 5.8% to 33.7% in 1- to 4-year-old groups, with significant reductions in 1- to 3-year-old groups. Drought significantly reduced the Shannon and Simpson indices of soil bacteria (by 11.3% and 38.7%, respectively) as well as the Chao1 and Ace indices of fungi (by 23.0% and 22.5%, respectively) in the 1-year-old group, but did not affect α-diversity of soil microorganisms in other age classes. At the phylum level, the abundance of Proteobacteria decreased while that of Actinobacteria increased across all bamboo age groups, and the abundance of Ascomycota fungi generally increased. Under drought conditions, the microbial carbon use efficiency (CUE) in the rhizosphere of bamboos of all ages increased, with an increase ranging from 4.9% to 23.1%, and the highest CUE was observed in 1-year-old group. Structural equation modeling showed that soil microbial CUE was directly influenced by soil nutrient content, nitrogen cycle-related enzyme activities, and changes in microbial community composition, and was indirectly regulated by soil pH. In conclusion, drought significantly altered microbial community composition by modifying soil chemical properties, enzyme activities and increased soil microbial CUE, and such effect diminished with increasing bamboo age.

Response of fiber anatomical characteristics of Fraxinus mandshurica to climate change in Maoershan, Northeast China

LIU Ye, WANG Xigang, ZENG Fansuo, ZHAN Yaguang, ZHAO Haifeng, TANG Ying, XIN Ying

2025, 36(11):  3277-3286.  doi:10.13287/j.1001-9332.202511.005

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Fraxinus mandshurica is a native high-quality timber species in Northeast China. The anatomical characteristics of its wood fibers are crucial indicators of wood performance. In the progeny test forest of F. mandshurica in Maoershan Experimental Forest, we investigated the response of fiber anatomical characteristics of whole ring, early-wood, and latewood to climate change by dendrochronology and wood anatomy methods. The results showed that juvenile F. mandshurica experienced a rapid growth period of approximately 10 years. From 2003 onwards, the ring width, fiber cell number, and total fiber cell area showed fluctuating increases, reaching peak values in 2011. At 2011, the ring width was 3749.59 μm, fiber cell number was 3750, and total fiber cell area was 760388.85 μm². There was a consistent overall correlation among the anatomical characteristics of fibers in the whole ring, earlywood, and latewood. The ring width was significantly positively correlated with both fiber cell number and total fiber cell area. The ring width, fiber cell number, and total fiber cell area of earlywood were primarily constrained by precipitation. These characteristics showed a significant negative correlation with precipitation in March, a significant positive correlation with precipitation in April, and negative correlation with temperature in June. The ring width, fiber cell number, and total fiber cell area of latewood were significantly negatively correlated with the minimum temperature and precipitation in September, and significantly positively correlated with maximum temperature in September. Under the low-temperature event, ring width, fiber cell number, and total fiber cell area decreased significantly by 19.7%, 24.2%, and 22.0%, respectively. Following the event, the resilience was 1.14, 1.14, and 1.26. Both temperature and precipitation jointly affected ring width of earlywood and latewood and fiber cell growth. The low-temperature event could significantly reduce both fiber cell number and total fiber cell area, thereby inhibiting radial growth. In response to the low-temperature event, F. mandshurica showed a significant capacity for recovery.

Simulation of longitudinal knot growth and sampling strategy in Larix olgensis

LI Zelin, JIA Weiwei, ZHAO Guoqiang

2025, 36(11):  3287-3295.  doi:10.13287/j.1001-9332.202511.006

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Knots are common defects in wood, the size of which has a major influence on mechanical performance and visual quality. To elucidate the longitudinal growth patterns of knots, we examined 27 individuals of Larix olgensis from the Mengjiagang Forest Farm in Heilongjiang Province. Based on 1137 knot samples, we simulated the vertical growth dynamics of knots along the stem and developed a predictive model for knot width and sampling strategy. The results showed that Hossfeld model was the best baseline among the seven commonly used models of growth. We further constructed a reparameterized model by incorporating tree-level and knot-level variables, as well as a mixed-effects framework improved with random effects. The mixed-effects model had the best performance, with R² increased to 0.6051 and RMSE reduced to 2.3865. We tested four sampling strategies to calibrate the mixed model, and the results showed that sampling design strongly influenced predictive accuracy. Scheme 2, randomly selecting seven knots from the upper stem, achieved the best balance between accuracy and efficiency. Model parameters indicated that knot width increased with branch insertion height and angle but decreased with increasing height diameter ratio of L. olgensis. We recommended to use the mixed-effects model in forest management combined with sampling of seven upper-stem knots for prediction. Moreover, priority should be given to pruning upper-stem branches to effectively reduce knot width and improve timber quality.

Relationship between topsoil pollen and modern vegetation in the Tianchi Lake watershed in the karst trough valley of eastern Sichuan Basin, China

HAN Sha, JIANG Yongjun, HAO Xiudong, TIAN Xing, OUYANG Xuhong, QIN Linjuan, WEI Jiasheng, DAI Tao

2025, 36(11):  3296-3304.  doi:10.13287/j.1001-9332.202511.004

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The correspondence between topsoil pollen and modern vegetation is critical for reconstructing paleove-getation and paleoenvironment from palynological fossil records. Taking the Tianchi Lake watershed in the karst trough valley of eastern Sichuan Basin as a case, we explored the correspondence between pollen assemblages and current vegetation across seven land use types: cultivated land, abandoned cropland, shrublands, mixed forest, bamboo forest, pomelo orchard, and plum orchard. The results showed that the proportion of coniferous trees pollen was the highest (57.1%), followed by herbaceous plant pollen (25.7%), while that of fern spore was relatively low (22.8%), and broad-leaved tree pollen had the lowest proportion (17.2%). The proportion of broad-leaved tree pollen deviated from the typical subtropical evergreen broad-leaved forests. Such discrepancy might be attributed to the dilution effect of high-yield pollen on low-yield pollen and the inherent characteristics of the pollen. The topsoil pollen assemblages from different land use types showed a strong correspondence with the modern vegetation, particularly in terms of constructive and dominant species. The PCA results showed that pollen could distinguish the seven land use types. Among these, cultivated land and bamboo forests showed weaker correlations with Poaceae and Amaranthaceae, possibly due to soil disturbance from cultivation and the thick humus layer beneath bamboo forests. The representativeness of topsoil pollen varied across species or genera, with Pinus over-represented and deciduous Quercus and Poaceae under-represented. There were significant differences in average spore and pollen concentration among land use types, indicating that spore and pollen concentrations could reflect the intensity of human activities. The topsoil pollen assemblages in the Tianchi Lake watershed broadly reflected the overall characteristics of current vegetation. However, the interpretation of pollen assemblages required comprehensive consideration of various influencing factors, including soil erosion and palynological preservation conditions.

Plant collection activities of Western botanists in Southwest China (1840-1949)

ZHONG Xiaoxue, WU Renwu, NIE Wenbin, LIU Jiachen, HU Xuhao, BAO Zhiyi

2025, 36(11):  3305-3314.  doi:10.13287/j.1001-9332.202511.009

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Since the 19th century, as Western botanical expeditions extended into the hinterland of Asia, Southwest China has gradually become an important region for plant collection. However, systematic quantitative analyses of such plant collection activities are lacking. We reviewd the plant collection activities of eight renowned Western botanists in Southwest China from 1840 to 1949, as well as the taxonomic composition of the collected plants. A total of 56273 plant specimens were examined in this study, belonging to 7940 species, 1742 genera, and 304 families. Temporally, the sheets of specimens collected peaked during the thirty years from the late 19th century to the early 20th century. Spatially, the collections were concentrated in the Hengduan Mountains and the Yunnan-Guizhou Plateau, particularly in middle- and high-altitude regions. The most frequently collected plants belonged to families such as Ericaceae, Rosaceae, and Asteraceae. The plant collection activities of Western botanists in Southwest China provided specimen resources for taxonomic research, and offered valuable scientific references for advancing regional biodiversity conservation.

Spatial and temporal variations in grassland aboveground biomass and their drivers in central Inner Mongolia, China

ZHANG Shenlin, WU Tianjun, HAN Ling, WANG Liuhua, SUN Hailian

2025, 36(11):  3315-3326.  doi:10.13287/j.1001-9332.202511.007

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Grasslands of central Inner Mongolia are a crucial component of ecological security barrier in northern China. By integrating field-measured quadrat data, remote sensing imagery, and environmental variables of grasslands in central Inner Mongolia, we developed aboveground biomass estimation models using machine learning algorithms, and generated high-resolution spatial distribution datasets for the period 2000-2020. We further analyzed the spatiotemporal variations and driving factors of aboveground biomass by the trend analysis and GeoDetector methods. The results showed that among multiple machine learning models, the gradient boosting machine (GBM) algorithm demonstrated optimal performance, with the coefficient of determination (R²), mean absolute error (MAE) and root mean square error (RMSE) being 0.58, 42.40 g·m^-2, and 56.99 g·m^-2, respectively. From 2000 to 2020, aboveground biomass showed a fluctuating upward trend, with a multi-year average value of 148.72 g·m^-2. Spatially, aboveground biomass displayed a pattern of low values in the northwest and high values in the southeast. Overall, 77.9% of the region experienced increases in aboveground biomass, while only 0.3% showed significant degradation. Factor detection revealed that annual precipitation, growing season precipitation, soil nitrogen, and soil organic carbon content were the primary drivers of spatial heterogeneity in aboveground biomass, and all interactions exhibiting enhanced effects. Our results could provide scientific basis for the management and sustainable development of grassland resources in central Inner Mongolia.

Effects of restoration measures on soil organic carbon fractions in degraded grasslands in China

GUO Zihua, HAO Huanhuan, MA Jie, ZHOU Ao, CUI Qingliang, CHEN Xiaopeng, ZHAO Xiang

2025, 36(11):  3327-3338.  doi:10.13287/j.1001-9332.202511.002

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Reseeding, fertilization, and fencing are widely used restoration measures for degraded natural grasslands. Soil organic carbon fractions serve as key indicators for evaluating carbon turnover and sequestration during the restoration of degraded grasslands. Clarifying the impacts of various restoration measures on soil organic carbon fractions can provide a scientific basis for selecting appropriate restoration strategies. Based on 269 data pairs from 73 papers, we evaluated the effects of three restoration measures-reseeding, fertilization, and fencing-on soil organic carbon fractions in degraded natural grasslands in China. The results showed that reseeding significantly increased soil total organic carbon by 18.7%, dissolved organic carbon by 12.4%, and easily oxidizable carbon by 17.7%. Fertilization significantly increased easily oxidizable carbon by 15.5% and light fraction organic carbon by 11.5%, but significantly reduced microbial biomass carbon by 15.5%. Fencing significantly increased dissolved organic carbon by 12.7%, microbial biomass carbon by 17.8%, and particulate organic carbon by 14.7%, while significantly reduced light fraction organic carbon by 9.7%. Under different environmental conditions, reseeding significantly enhanced soil organic carbon content, whereas fencing markedly enhanced soil microbial biomass carbon. In contrast, the effects of fertilization on soil organic carbon fractions exhibited considerable uncertainty. Correlation analysis indicated that soil dissolved organic carbon, light fraction organic carbon, and mineral associated organic carbon significantly increased with increasing total soil organic carbon content, whereas microbial biomass carbon, easily oxidizable carbon, and particulate organic carbon remained relatively stable. Soil moisture and ammonium content are key factors influencing changes in soil organic carbon during the restoration of degraded grasslands.

Ecological efficiency of different rice cropping systems in Southeast China

PENG Qingxia, LIN Zhimin, CHEN Gui, SU Kai, LIN Wenxiong

2025, 36(11):  3339-3352.  doi:10.13287/j.1001-9332.202511.012

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We conducted a field experiment on three rice cultivation patterns, namely ratoon rice, single-cropping rice, and double-cropping rice, using hybrid rice and conventional rice varieties as materials in 2021-2022. We evaluated the ecological efficiency differences across rice cultivation patterns from multiple dimensions, including yield and material distribution, greenhouse gas emissions, carbon nitrogen footprint, and carbon balance, using closed static greenhouse gas collection and life cycle assessment methods. The results showed that the ratoon rice pattern had the highest average yield and daily average yield, followed by the double-cropping rice pattern with the lowest daily average yield, and the lowest single-cropping yield ranking second in daily average yield. In the rice ratooning system, non-structural carbohydrate (NSC) translocation amount and translocation rate in various plant parts were significantly higher in ratoon season rice than in its main crop, single-cropping rice, and both early and late crops of double-cropping rice. Across all organs, the average contribution of NSC remobilization to grain yield formation was 7.5% over the two years, being 19.9% and 12.8% higher than that of the main crop and single-cropping rice, respectively, and 67.0% and 77.0% greater than that of early and late rice in the double-cropping system. Compared with the single-cropping and double-cropping, the ratoon rice reduced CO₂ emission intensity by 2.3%-725.0% and 6.8%-732.6% in 2021 and 2022, CH₄ emission intensity by 31.2%-751.8% and 27.6%-746.4%, N₂O emission intensity by 7.4% and 4.6%, resource utilization efficiency by 23.5%-24.6% and 57.4%-57.5%, and daily economic benefits by 36.0%-35.7% and 81.9%-101.9%, respectively. In 2021 and 2022, the carbon footprint of the ratoon rice pattern increased by 31.2% and 11.2% respectively compared to single-cropping rice, and decreased by 19.1% and 28.2% respectively compared to double-cropping rice. The nitrogen footprint increased by 44.2% and 46.8% compared to single-cropping rice, and decreased by 10.1% and 15.4% compared to double-cropping rice. The carbon budget surplus of ratoon, single-cropping, and double-cropping rice were 24623.5, 13342.6, and 23772.2 kg CO₂-eq·hm^-2, respectively. It is suggested that the ratoon rice, especially the regenerated season rice, has high daily yield and low greenhouse gas emission intensity per unit yield, achieving stronger synergy between yield and carbon surplus, which is a sustainable, ecologically efficient, and environmentally friendly cropping system well-suited to rice production in Southeast China.

Silicon dynamics and cycling flux in soil-crop systems of Suzhou rice cultivation: A comparative analysis of multiple cropping rotation

HUANG Sihua, PU Lijie, XIE Jiayi, GE Yun

2025, 36(11):  3353-3366.  doi:10.13287/j.1001-9332.202511.013

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In paddy soil-crop system, the mutual transformation of silicon (Si) accelerated biogeochemical cycle, which is a significant factor governing Si export in terrestrial ecosystems. To understand the Si cycling in paddy field and their responses to agricultural management during paddy production, we conducted a 3-year (2020-2022) in-situ monitoring of soil Si and rice Si accumulation in typical rice cultivation systems of Suzhou (rice-rape rotation system, rice-wheat rotation system, rice-wheat/rape rotation system, and integrated rice-aquaculture farming system). We evaluated soil and rice Si pool, as well as the annual Si exchange fluxes in the soil-rice system. The results showed that both the labile and total Si pools exhibited a declining trend during the rice growing season across all the examined systems, reaching their lowest levels at maturity, and followed by a rebound trend with fluctuations. The Si fixation by crops ranged from (431.65±115.73) to (670.33±211.07) kg·hm^-2·a^-1, primarily contributed by rice plant (88.0%-100%). Variations in annual biosilicon production among different rotation systems were mainly influenced by crop combinations under rotation and fallow practices, as well as soil available Si levels. Si input ranged from (61.34±11.26) to (130.36±30.55) kg·hm^-2·a^-1(via irrigation and rainfall), while Si output ranged from (149.20±47.30) to (231.22±83.23) kg·hm^-2·a^-1(via crop harvest). The Si fluxes contributed by crop residues return ranged from (296.60±74.55) to (462.52±139.26) kg·hm^-2·a^-1. From the perspective of crop Si utilization, soil Si pools contributed the most to crop Si accumulation (74.3%-89.5%), followed by the irrigation (11.7%-25.7%). Overall, rice systems in the study area exhibited a net loss of Si. In the short term, both the plant-available Si and amorphous Si pools exhibited a slight decrease, while in the long term, systems with higher net Si output flux exhibited lower content of labile Si. Appropriate Si conservation strategies should be taken to reduce the depletion rate of labile Si in paddy field.

Effects of nitrogen and phosphorus management on soil enzyme activity, nutrient supply, and wheat yield

JIN Haiyang, ZHAO Yuhao, LI Chunmiao, WANG Jiarui, DU Simeng, HE Ning, ZHENG Fei, LI Xiangdong

2025, 36(11):  3367-3377.  doi:10.13287/j.1001-9332.202511.015

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To explore the effects of nitrogen (N) and phosphorus (P) management at different growth stages on soil nutrient transformation, supply, and wheat yield formation, we conducted a field experiment at two sites of Longting (Kaifeng) and Dancheng (Zhoukou). With identical total N and P application rates, we designed four treatments with different N and P application frequencies: 50% basal, 50% jointing 2-split N + basal 1-split P (2N1P), 50% basal, 30% jointing, 20% anthesis 3-split N + basal 1-split P (3N1P), 50% basal, 50% jointing 2-split N + 70% basal, 30% jointing 2-split P (2N2P), and 50% basal, 30% jointing, 20% anthesis 3-split N + 70% basal, 30% jointing 2-split P (3N2P). We analyzed the impacts of these nitrogen and phosphorus management strategies on soil enzyme activities, soil nutrient, wheat dry matter accumulation, and grain yield. Compared with the 2N1P treatment, the 3N2P treatment significantly enhanced the activities of soil β-1,4-glucosidase and cellobiohydrolase during the wintering, jointing, and anthesis stages. In contrast, the 2N2P treatment significantly elevated the activities of soil leucine aminopeptidase and phosphatase during the jointing, anthesis, and maturity stages. The 3N2P treatment significantly increased soil available phosphorus content during the jointing and flowering stages, while the 2N2P treatment significantly increased soil available phosphorus content specifically during the anthesis stage. The 3N2P treatment significantly promoted dry matter accumulation during the anthesis and maturity stages, with an increase range of 14.3%-25.7%. Both the 2N2P and 3N2P treatments significantly improved wheat grain yield, with 3N2P treatment achieving higher yield increase of 7.8%-10.8%. In conclusion, the application of nitrogen fertilizer in two to three split doses and phosphorus fertilizer in two split doses, particularly 3N2P could enhance soil nutrient transformation and availability, promote pre- and post-anthesis dry matter accumulation in wheat, and thereby increase grain yield.

Effects of replacing chemical fertilizers with organic fertilizers on yield of dryland forage maize and farmland CO₂ emissions

YANG Tong, XIE Junhong, TANG Xinyue, TIAN Ye, WEI Ruifang, ZHANG Kangkang, WANG Tingting, UMAR Daraz

2025, 36(11):  3378-3386.  doi:10.13287/j.1001-9332.202511.014

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The fully mulched double ridge-furrow planting of maize is a typical high-yield model in the Loess Pla-teau's semi-arid region. Exploring the optimal substitution ratio of organic fertilizer for chemical fertilizer is important to enhance crop yield of forage maize and reduce CO₂ emissions. We conducted an experiment on organic fertili-zer substitution for chemical fertilizer in forage maize in the semi-arid region of the Loess Plateau between 2023 and 2024. There were four treatments, including no nitrogen application (S₁), chemical fertilizer alone (S₂, inorganic nitrogen 200 kg·hm^-2), 25% organic fertilizer substitution for chemical fertilizer (S₃, organic nitrogen 25% + inorganic nitrogen 75%), and 50% organic fertilizer substitution for chemical fertilizer (S₄, organic nitrogen 50% + inorganic nitrogen 50%). We measured the dry matter accumulation of forage maize, soil respiration, yield, and farmland CO₂ emissions, as well as carbon emission efficiency and carbon balance. The results showed that substituting chemical fertilizers with organic fertilizers increased the dry matter accumulation of forage maize during the filling and maturity stages compared to the application of chemical fertilizer alone. Specifically, the average dry matter accumulation during the filling stage under treatments S₃ and S₄ increased by 88.0% and 79.1%, respectively, compared to S₁, and by 79.1% and 6.4% compared to S₂. At harvest, the increases were 81.3% and 78.7% compared to S₁, and 15.3% and 13.6% compared to S₂. The rational substitution of chemical fertilizers with organic fertilizers significantly increased the yield of forage maize. In 2023 and 2024, the yield of treatment S₃ increased by 84.9%, 9.9% and 140.1%, 17.9% compared to S₁ and S₂ respectively, and by 18.1% and 14.5% compared to S₄. Soil respiration rate and the differences among treatments during the growth period of forage maize were greater than those during the fallow period. The substitution of chemical fertilizer with organic fertilizer increased soil respiration rate compared to the application of chemical fertilizer alone. The higher the proportion of organic fertilizer substitution, the greater the soil respiration rate. Specifically, the annual average respiration rates of treatments S₃ and S₄ increased by 46.3% and 53.9% compared to S₁, and by 5.4% and 10.9% compared to S₂, respectively. The total CO₂ emissions increased by 43.9% and 51.9% compared to S₁, and by 5.7% and 11.5% compared to S₂, respectively. The rational substitution of chemical fertilizer with organic fertilizer improved carbon emission efficiency, with the highest value under treatment S₃, which was 42.7%, 7.7%, and 18.8% higher than that of S₁, S₂, and S₄, respectively. Collectively, the partial substitution of 25% chemical fertilizer with organic fertilizer significantly enhanced dry matter accumulation in forage maize during the grain-filling and maturation stages, synergistically increased both yield and farmland carbon emission efficiency, and demonstrated a strong carbon sequestration effect. This approach offered a carbon-friendly fertilization strategy for forage maize production under whole plastic film mulching and double ridge-furrow planting in the semi-arid regions of the Loess Plateau.

Influence of landscape patterns on riverine nitrogen concentrations in Qingshan Lake headwater watershed

YANG Ziqing, XU Jiani, XING Mengxiao, LIU Dongxin, WANG Cheng, WU Jianhong, HE Shengjia, JIANG Peikun

2025, 36(11):  3387-3396.  doi:10.13287/j.1001-9332.202511.025

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Understanding the relationship between landscape patterns and water quality in river headwater watersheds is essential for developing sustainable landscape policies to protect water quality in water source areas. With the Qingshan Lake headwater watershed as the research object and based on the data of 25 water sampling sites between 2023 and 2024, we used the partial least squares regression (PLSR), non-parametric change-point analysis and bootstrap methods to quantitatively assess the impacts of landscape patterns on riverine nitrogen concentration during high-flow, normal-flow, and low-flow periods. The results showed that there were significant differences in landscape dominance and fragmentation among different sub-watersheds. High landscape weighted load index (LWLI) values (>0.50) were predominantly observed in low-altitude, gently sloping areas were characterized by extensive “source” landscapes, whereas low LWLI value (<0.10) were mainly distributed in mid-altitude regions dominated by forests. The optimal PLSR model accounted for 60.6%, 69.7%, and 78.3% of the variance in total nitrogen (TN) concentrations during the high-flow, normal-flow, and low-flow periods, respectively. Variable importance in projection (VIP) analysis revealed that LWLI was the dominant landscape factor driving TN concentrations throughout the year. The proportion of build-up land primarily affected TN concentrations during the high-flow period, while the proportion of grassland and the largest patch index had more substantial effects during the normal-flow period. During the low-flow period, the proportion of forest land emerged as the most dominant factor. LWLI and the proportion of construction land exerted positive effects on TN concentrations, whereas the proportion of grassland, the largest patch index, and the proportion of forest land exhibited negative effects. When the LWLI value exceeded 0.35, the cumulative probability of abrupt changes in TN concentration during the high-flow period exceeded 95.0%, thereby elevating the risk of water quality degradation. Optimizing landscape patterns could effectively control non-point source pollution and improve water quality in headwater watersheds.

Aquatic plants promote denitrification and inhibit ammonia volatilization: A meta-analysis

ZHENG Kezhen, PAN Yongchun, SHE Dongli, HUANG Yihua, ZHAO Junhan, SUN Xiaoqin, WANG Hongde

2025, 36(11):  3397-3407.  doi:10.13287/j.1001-9332.202511.032

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To elucidate the regulatory effects of aquatic plants on denitrification and ammonia volatilization in sha-llow water ecosystems and the underlying mechanisms, we evaluated the regulatory effects of aquatic plants on denitrification and ammonia volatilization and their key driving factors using meta-analysis based on 421 sets of experimental data from 35 publications published between 2007 and 2024. The results showed that aquatic plants significantly promoted denitrification (by 99.2%) through root exudation of organic matter, improvement of sediment environment, and provision of microbial habitat matrix. Shallow lakes and floating plants exhibited the strongest effects, increasing by 265.4% and 213.6%, respectively. Aquatic plants significantly inhibited ammonia volatilization (by 31.8%) through root absorption of NH₄⁺-N, formation of physical barriers, and secretion of organic acids. The constructed wetlands and submerged plants exhibited the strongest inhibitory effects, reducing ammonia volatilization rates by 38.7% and 60.9%, respectively. The regulatory effects of aquatic plants on denitrification and ammonia volatilization were significantly influenced by environmental factors. Neutral to weakly alkaline pH (7-8), higher temperature (>20 ℃), higher concentration of NO₃^--N (>1 mg·L^-1), and high concentration of dissolved organic carbon (DOC) (>10 mg·L^-1) significantly enhanced the promoting effect of aquatic plants on denitrification. High concentration of NH₄⁺-N (>50 mg·L^-1), high concentration of dissolved oxygen (DO) (>5 mg·L^-1), low concentration of NO₃^--N (<1 mg·L^-1), and lower concentration of DOC (2-10 mg·L^-1) signi-ficantly weakened such effect. The inhibitory effect of aquatic plants on ammonia volatilization was significantly enhanced at higher temperatures (>20 ℃), and significantly weakened under acidic conditions (pH<7), lower temperatures (<20 ℃), and lower concentration of NH₄⁺-N (<50 mg·L^-1). In summary, aquatic plants in sha-llow water ecosystems can significantly promote denitrification and inhibit ammonia volatilization through multiple mechanisms, and are regulated by environmental factors. These results could provide a scientific basis for nitrogen pollution control and ecological restoration of water bodies.

Spatiotemporal variations and driving factors of the transpiration-to-evapotranspiration ratio in different ecosystems of Northeast China

WANG Jingli, ZHANG Yongsheng, YU Wenying, CAI Fu, CHEN Nina, YAN Guofeng, ZHAO Yijin

2025, 36(11):  3408-3418.  doi:10.13287/j.1001-9332.202511.021

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The transpiration-to-evapotranspiration ratio (T/ET) characterizes the proportion of vegetation transpiration in evapotranspiration and is of great significance for understanding the role of vegetation transpiration in ecosystem water cycling. We utilized multi-source data to analyze the variations and driving factors of T/ET in three ecosystem types of Northeast China from 2001 to 2020, including forests, croplands, and wetlands. The results showed that the interannual variation of T/ET in forests, croplands, and wetlands exhibited a slight upward trend from 2001 to 2020, with annual increase rates of 0.0006, 0.0037, and 0.0009, respectively. T/ET exhibited a unimodal pattern during the growing season, rising from May, peaking in July and August, and then declining. The proportions of areas showing an upward trend in T/ET in forest, cropland, and wetland ecosystems were 59.7%, 84.7%, and 55.1%, respectively. During the growing season, the T/ET ratios of forest ecosystems in the southeastern part of the study area, cropland ecosystems in the central part, and wetland ecosystems in the southern part were all higher than those of the same ecosystem type in other regions. The dominant biological driving factors for T/ET changes in the three ecosystem types were gross primary productivity (GPP) and solar-induced chlorophyll fluorescence, but with differences among different ecosystems. In forest ecosystems, the explanatory power of relative humidity, precipitation, and minimum temperature was higher than that of other environmental factors. In croplands, the effects of saturation vapor pressure deficit, relative humidity, and precipitation were more significant. In wetlands, T/ET was mainly influenced by net radiation, precipitation, and minimum temperature. Among the combinations of biological and environmental factors influencing the changes in T/ET across different ecosystems, gross primary productivity and relative humidity constituted the most explanatory combination.

Spatio-temporal variations of vegetation in Jinsha River Basin and their responses to climatic factors

ZHANG Wenjie, ZHAO Qianzuo, CUI Lei, LI Chong, ZHANG Xuan, CHENG Hongguang

2025, 36(11):  3419-3430.  doi:10.13287/j.1001-9332.202511.023

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Vegetation plays a crucial role in ecosystem functioning by linking energy flow and material cycling. Understanding vegetation dynamics and their responses to climate is essential for ecosystem conservation. Based on normalized difference vegetation index (NDVI), precipitation, and temperature data of the Jinsha River Basin from 2001 to 2022, we used Mann-Kendall trend test and Sen's slope analysis to analyze the temporal and spatial variations of vegetation cover, while applied partial correlation analysis to explore the lagged responses of vegetation to temperature and precipitation and the lag differences across the responses of different land types. Results showed that vegetation coverage in the basin improved overall from 2001 to 2022, with the increasing rate of NDVI being 0.002·(10 a)^-1. There were significant spatial variations of vegetation changes, with 25.4% of the area showing improvement. The mean NDVI negatively correlated with altitude (correlation coefficient was -0.76). The basin's climate condition exhibited drier and warmer trends. NDVI showed a one-month lagged response to precipitation and a no-lagged response to temperature. Vegetation coverage in cultivated land and shrubland increased, while that in grassland and forest remained stable. The changes in grassland coverage had the strongest correlation with both precipitation and temperature, while forest coverage had the lowest correlation. Land types exhibited varying lag times in their response to the variations of precipitation and temperature. The lag time of precipitation response for cultivated land, grassland, and shrubland was one month, while forest showed an immediate response. The cultivated land and forest showed immediate response to temperature, while grassland and shrublands had significant differences in lag time. These findings would offer scientific basis for ecological protection and resource management in the basin and provide methodological insights for examining vegetation dynamics in other regions.

Relationship between extreme climate indices and atmospheric circulation modes based on multivariate wavelet coherence in the Yilong Lake Basin, Southwest China

BAO Ningying, SONG Weifeng, HU Yan-ting, ZHANG Yali, GUO Yutong, LI Jie, GONG Yunhui

2025, 36(11):  3431-3442.  doi:10.13287/j.1001-9332.202511.022

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Yilong Lake, one of the nine plateau lakes in Yunnan, is a typical shallow plateau lake with high sensitivity to climate change. Understanding how extreme climate variability affects the basin is therefore critical for regional ecological security and socio-economic development. Based on daily meteorological data from 1979 to 2023 in the Yilong Lake Basin, we analyzed the trends of extreme climate changes and their relationships with atmospheric circulation modes using linear regression, Mann-Kendall test, wavelet transform coherence (WTC) analysis, and multiple wavelet coherence (MWC) analysis. The results showed that rainfall intensity and air temperature increased significantly from 1979 to 2023, indicating a pronounced warming-wetting trend. Stronger Pacific Decadal Oscillation (PDO) and North Atlantic Oscillation (NAO) phases were associated with higher frequencies of heavy precipitation events. Enhanced East Atlantic/West Russia (EA/WR) patterns corresponded to wetter and cooler conditions, and stronger El Niño-Southern Oscillation (ENSO) phases corresponded to hotter and drier conditions. Changes in individual extreme climate indices were synergistically influenced by the combinations of atmospheric circulation modes. Based on the percent area of significant coherence (PASC) of multiple wavelet, the three-mode combination PDO-NAO-EA/WR dominated the variability of consecutive dry days (PASC=26.1%), consecutive wet days (22.5%), cold day index (20.5%), summer days (18.7%), warm night index (13.5%), and the warm day index (10.6%). The four-mode combination PDO-NAO-EA/WR-ENSO dominated the variability of the cold night index (11.0%). PASC differences among multi-mode combinations were not significant for indices such as max 1-day precipitation amount, heavy precipitation days, very wet days, and simple daily intensity index.

Horizontal ecological compensation based on ecosystem carbon sequestration flow in Fujian Province

HUANG Jixing, LIU Wanyi, LIN Jinhuang, DAI Yongwu, HUANG Yan, OUYANG Youquan

2025, 36(11):  3443-3456.  doi:10.13287/j.1001-9332.202511.028

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Constructing a scientifically sound ecological compensation mechanism is a crucial approach to harmonize regional ecological conservation with socio-economic development, which has significant implications for the sustainable use of ecosystem services. Based on multi-source remote sensing data, we quantified the supply and demand of ecosystem carbon sequestration service in Fujian Province. With the supply-demand ratio, hot/cold spot analysis, and breakpoint-field strength models, we examined the spatial flow features (direction, rate, and flux) of carbon sequestration services in Fujian from 2000 to 2020, and further quantified ecological compensation with considerations of payment capacity and willingness to pay. The results showed that both the supply and demand of ecosystem carbon sequestration in Fujian Province increased significantly between 2000 and 2020. The supply showed a northwest high and southeast low distribution, while the spatial distribution of demand exhibited the opposite pattern. There was a mismatch between dominant supply and demand for ecosystem carbon sequestration services in Fujian Province, which was worsening over time. Coastal areas typically exhibited a supply-demand deficit with low supply-high demand and high supply-high demand, while other regions mostly showed a supply-demand surplus with high supply-low demand. In 2020, the ratio of counties between the supply region and the demand region for ecosystem carbon sequestration was 9:32, showing a spatial pattern of west supply and east input. The total carbon outflow from the supply region was 4264107 t, with the largest outflow from Zhangping City and the largest inflow to Changtai District. The payment to the compensated areas should been 182 million yuan, but the actual expenditure was 91.16 million yuan. Changtai District had the highest actual expenditure, while Zhangping City had the highest actual income.

Construction and evaluation of ecological network in the Yellow River Delta High-efficiency Ecological Economic Zone

ZHU Yajie, LI Yunzhao, LIU Yanzhi, TANG Ziwei, YAN Chang, BAI Yunyi, YU Junbao, YANG Jisong

2025, 36(11):  3457-3466.  doi:10.13287/j.1001-9332.202511.027

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The fragmentation of habitat patches is rising due to economic development and urban expansion. The systematic design of an ecological network can link fragmented habitat patches, improve landscape connectivity, augment ecosystem service capabilities, and foster the robust development of the ecosystem. We employed the methods of morphological spatial pattern analysis and landscape connectivity analysis to identify ecological source areas, and utilized the minimal cost resistance model through the superimposition of multiple factors to construct the ecological resistance surface. Combining circuit theory to extract ecological corridors, grips, and obstacle points, we constructed the ecological network of the Yellow River Delta Efficient Ecological Economic Zone by using the “source-corridor-node” paradigm and analyzed the structure and resilience of this network. We identified 41 ecolo-gical sources regions, with a total area of 2994.45 km². We extracted 21 first-level ecological corridors, 26 second-level ecological corridors, and 18 third-level ecological corridors, with a total length of 1655.42 km and an average length of 25.46 km. We identified 127 ecological pinch points with a total of 32.92 km² and 20 ecological obstacles, corresponding to regions that required key ecological conservation and restoration work. The ecological network closure index was 0.74, the connectivity index was 2.32, and the connectivity index was 0.83, indicating a relatively comprehensive ecological network structure. The initial values of the connectivity robustness and vulnerability robustness of the ecological network were 0.98 and 0.42, respectively. The critical values for the stability of the ecological network function were an edge failure ratio of 45% and a node failure ratio of 20%. Generally, our findings have significant reference and guiding value for the landscape fragmentation management, biological habitat protection, development of ecological security, and ecdogical network evaluation in the Yellow River Delta Efficient Ecological Economic Zone.

Landscape ecological risk assessment and ecological security pattern construction in Chuxiong Yi Autonomous Prefecture, Yunnan Province, China

CHEN Kunlun, LIN Rumeng, CHEN Nenyu, HE Lina, HE Qingjun

2025, 36(11):  3467-3478.  doi:10.13287/j.1001-9332.202511.026

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Exploring the landscape ecological risk and ecological protection and restoration strategies in the dry-hot valley region of the Jinsha River Basin is of great significance for promoting the high-quality development of the Yangtze River Economic Belt. With Chuxiong Yi Autonomous Prefecture as the research area, we evaluated landscape ecological risk and determined its ecological background using the InVEST and Zonation models, and further constructed the ecological security pattern by integrating the ecological characteristics of dry-hot valley regions to guide the formulation of ecological restoration strategies, thereby ensuring regional ecological security. The results showed that there is a patchy and locally aggregated pattern of ecological risks , with high-risk patches being concentrated in dry-hot valley areas and urban expansion zones and low-risk areas being mainly found in mountainous forest regions. With an area threshold of 5 km², we identified 154 ecological sources, accounting for 19.5% of the total area of the prefecture, mainly distributed in Ailao Mountain, Baicao Ridge, and Wumeng Mountain with large forest area. We extracted a total of 241 ecological corridors with a combined length of 2779.49 km, which showed a distribution pattern of shorter corridors around the periphery and medium-to-longer corridors in the interior. There were 173 ecological pinch points with a total area of 57.87 km², and the area of the largest pinch point was 13.44 km². The number of ecological barriers was 101 with a total area of 172.14 km², mainly distributed in areas heavily affected by human activities such as railways and expressways. Based on ecological sources, combined with the connectivity direction of ecological corridors and the resistance surface, we constructed an ecological security pattern of “three zones, four belts, and multiple points”, and proposed corresponding ecological restoration strategies. This study would provide theoretical support for ecological protection and sustainable development in Chuxiong Yi Autonomous Prefecture and offer reference value for ecological protection and restoration in dry-hot valley regions.

Efficiency comparison of multi-source identification and ecological security pattern construction in Yan'an City from the perspective of service collaboration

CHI Baochun, YANG Li, ZHU Zongbin, YAO Longjie

2025, 36(11):  3479-3489.  doi:10.13287/j.1001-9332.202511.024

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Against the backdrop of increasing demands for multiple ecosystem services and intensifying spatial conflicts, constructing an ecological security pattern that ensures both synergy and sustainability has become a central issue in ecological conservation and territorial spatial governance. Available methods for source area identification are mostly based on simple equal-weight overlay or entropy-weighted overlay approaches. Although being practical to some extent, these methods are limited in enhancing the efficiency of multi-service synergies and mitigating trade-offs. To address such limitations, we introduced a scenario-regulated ordered weighted averaging (OWA) model and proposed an optimization approach for ecological security pattern construction oriented toward improving service synergy efficiency. With Yan'an City, a typical ecologically fragile area in Northwest China, as a case study, we tassessed six types of ecosystem services (habitat quality, water yield, soil conservation, carbon storage, cultural aesthetics, and windbreak-sand fixation) under seven risk-preference scenarios to identify optimal synergistic sources. We used Conefor and Linkage Mapper models to construct ecological security pattern under different scenarios, and evaluated their performance in terms of source protection efficiency and corridor network topology by comparing the OWA synergy-based method with the simple overlay and entropy-weighted overlay approaches. Results showed that the OWA synergy-based method consistently demonstrated lower levels of trade-offs among ecosystem services, higher average protection efficiency, and a more favorable network connectivity structure in both 2000 and 2020, outperforming the traditional source overlay methods. The OWA synergy-based approach maintained the highest average protection efficiency in both 2000 and 2020, and performed particularly well in estimating critical ecosystem services of the Loess Plateau, such as windbreak-sand fixation and carbon storage. In terms of network topology, the OWA synergy-based pattern exhibited higher closure and node connection efficiency, indicating stronger stability and fault tolerance. These findings would provide new insights into source identification and spatial optimization under the context of ecosystem service trade-offs, and offer theoretical guidance and practical references for the delineation of ecological restoration priority areas and the planning of territorial ecological restoration.

Spatial and temporal variations of fish communities in the North Creek Basin of Jiulong River and their environmental driving factors

SHI Zhining, QU Xiao, XIONG Fangyuan, LIU Han, YANG Min, LIU Lihua, XIN Wei, XU Wenfeng, CHEN Yushun

2025, 36(11):  3490-3500.  doi:10.13287/j.1001-9332.202511.035

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The North Creek Basin of the Jiulong River is located in a typical subtropical monsoon climate zone, characterized by distinct hydrological seasonality. However, systematic research on the temporal and spatial variations of its fish community structure and the underlying driving mechanisms remains lacking. To understand spatiotemporal patterns of fish communities and the driving factors in the North Creek Basin of the Jiulong River, we examined fish communities from 18 sampling sites in March (spring, the dry season) and September (autumn, the wet season) of 2021. A total of 58 fish species, belonging to 49 genera, 16 families and 4 orders, were collected throughout the year. The majority of the specimens were cyprinids, followed by flathead loaches and gobies. The dominant species in the dry season included Coptodon zillii, Rhinogobius giurinus, and Oreochromis niloticus. The dominant species were C. zillii and O. niloticus in the wet season. Species richness and Shannon index were significantly lower in the dry season than those in the wet season. Spatially, fish abundance in the mainstem was significantly lower than that in the tributaries. Redundancy analysis results indicated that water depth and dissolved oxygen were the key environmental factors influencing fish abundance and biomass patterns during the dry season. During the wet season, water temperature, dissolved oxygen, and permanganate index were the key factors affecting fish abundance and biomass patterns. This study revealed the spatiotemporal patterns and influencing factors of fish communities in the North Creek Basin, providing a scientific basis for fish diversity conservation and ecosystem health maintenance in subtropical rivers.

Reviews

Current status and prospects of terrestrial ecosystem carbon sink in the Dongting Lake Basin, China

CHEN Ming, LI Zhongwu, NIE Xiaodong, WANG Shilan, RAN Fengwei, CHEN Yue

2025, 36(11):  3501-3511.  doi:10.13287/j.1001-9332.202511.010

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The enhancement of carbon sequestration in terrestrial ecosystems is regarded as one of the most effective measures for mitigating global carbon emissions and climate change. Compared to that at the local scale, watershed terrestrial ecosystems at the watershed scale typically exhibit the characteristics of more complex hydrological processes, intense anthropogenic disturbance, independence and intact. The Dongting Lake basin, as one of the most representative watershed in China, exhibits low carbon sink stability but significant carbon sequestration potential. We reviewed current research on the spatiotemporal patterns, carbon storage, sequestration potential, and carbon storage stability along the Dongting Lake basin, and proposed future research prospects. Currently, the mea-surement and monitoring of terrestrial ecosystem carbon sinks primarily rely on conventional models, with the limitations of inconsistent validation standards, relatively low precision, and neglecting anthropogenic disturbances. Data sources are predominantly confined to land use and remote sensing imagery, which often suffer from insufficient spatial resolution and untimely updates, leading to considerable uncertainties in carbon sink estimation. Overall, forest ecosystems are the primary contributors to carbon sequestration across the basin, while farmland and wetland ecosystems exhibit substantial carbon sequestration potential. Further attention should also be directed toward the complex hydrological conditions and regional characteristics. There is a critical need to develop carbon cycle models that couple watershed hydrological processes with biogeochemical cycles. Additionally, we require a systematic assessment and quantification of the mechanisms underlying the influences of human activities on ecosystem carbon sequestration. Such efforts are essential for more accurately evaluating the carbon sequestration function, potential, and multi-scale drivers of the terrestrial ecosystem in the Dongting Lake basin, thereby offering scientific support for achieving China's “Dual Carbon” goals.

Research progress and prospect on the regulation of intercropping on soil aggregate structure and function

LI Ming'en, LAI Zeting, TIAN Jihui

2025, 36(11):  3512-3522.  doi:10.13287/j.1001-9332.202511.011

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Soil aggregates are the basic units of soil structure and play a crucial role in maintaining soil ecological functions. Intercropping has great potential to promote the formation and stabilization of soil aggregates. However, there is a lack of systematic summary on the mechanisms by which intercropping systems affect the structure and function of soil aggregates. We summarized the rhizosphere processes influencing soil aggregate formation, sorted out the effects and action mechanisms of root structure and morphology, root exudates, rhizosphere microorganisms, soil fauna, and rhizosphere physical processes on soil aggregate formation, and explored the potential processes and mechanisms by which intercropping drives soil aggregate formation by affecting root structure and morphology, root exudates, and rhizosphere microorganisms. Additionally, we reviewed the impacts of intercropping on organic carbon, nutrient content and availability, and microbial community characteristics in soil aggregates with different particle sizes. Finally, we prospected the research directions regarding the regulation of soil aggregate structure and function by intercropping, emphasizing that efforts should be strengthened in the following aspects: quantitative research on the process of soil aggregate formation regulated by intercropping; the effects of intercropping on functional microbial communities at the aggregate level and the corresponding regulatory mechanisms; the spatial and temporal scales of intercropping's impacts on soil aggregate structure; and the development of intercropping technologies and models based on the directional cultivation of macroaggregates.

Phosphate-solubilizing mechanisms and ecological functions of cold-tolerant phosphate-solubilizing microorganisms

YANG Guiqiao, ZHAN Juan, ZHANG Sheng, WANG Jianmei, PANG Xueyong

2025, 36(11):  3523-3534.  doi:10.13287/j.1001-9332.202512.033

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Phosphorus is an essential nutrient for plant growth, playing a crucial role in energy transfer and substance synthesis. The scarcity of available phosphorus in soil is an important factor restricting agricultural development and ecological restoration. Low temperature stress hinders plant physiological metabolism and inhibits soil phosphorus activation through pathways such as reducing soil enzyme activity. Phosphorus solubilizing microorgani-sms (PSM) with the capacity of cold resistance, can achieve biological activation of soil insoluble phosphorus, alleviate plant cold stress and promote growth, effectively alleviate plant phosphorus demand, mainly due to their low-temperature adaptability and phosphorus solubilizing ability. We summarized the types and distribution of cold resistant PSM, its cold resistance and phosphorus solubilization mechanisms, elaborated on its ecological functions in soil phosphorus cycling, microbial interactions, and plant growth, and explored the potential application of cold resistant PSM in sustainable agricultural development and ecological restoration in cold regions. We proposed further research directions for PSM in strain resource development, molecular mechanism analysis, and field application optimization, which would provide support for the efficient utilization of soil phosphorus resources in cold regions.

Degradation mechanisms and microbial remediation of micro- and nanoplastics: A comprehensive review

CHANG Xiao, LIU Qian, SUN Mengyao, ZHONG Rongzhen

2025, 36(11):  3535-3548.  doi:10.13287/j.1001-9332.202511.034

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Micro/nano plastics are emerging pollutants of global concerns due to their environmental persistence and potential ecological toxicity. We reviewed the generation pathways and microbial degradation mechanisms of micro/nano plastics, and assessed the application potential of microbial remediation. The abiotic degradation pro-cesses of micro/nano plastics mainly include photo-oxidation, thermal cracking, mechanical crushing, hydrolysis, and ozone degradation. Microorganisms gradually degrade high-molecular-weight polymers into oligomers and monomers by secreting depolymerases, and ultimately complete the biological mineralization process of micro/nano plastics. Microbial treatment technologies for the degradation of micro/nano plastics mainly include the use of high-tempera-ture resistant bacteria for ultra-high temperature composting and the genetic engineering of strains to synthesize enzymes capable of degrading micro/nano plastics. The bottlenecks for these technologies include low degradation efficiency, poor environmental adaptability, and difficulties in engineering scale-up. Future research should enhance experimental simulations of plastics under weathering or aging conditions, focus on exploring and utilizing microorganisms in extreme environments, and develop degradation enzyme systems based on synthetic biology for modification and optimization. Meanwhile, efforts should be made to promote their coupled application and large-scale verification with solid waste or sludge treatment processes, in order to provide technical support for the effective control of micro/nano plastic pollution.

Technology and Methods

Development of enzyme-linked immunosorbent assay with nanogold-labeled probes for detection of diarrhetic shellfish toxins

ZHAO Rui, HAN Lei, LIU Zhao, ZHANG Peipei, LIANG Yubo

2025, 36(11):  3549-3556.  doi:10.13287/j.1001-9332.202511.031

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Diarrheal shellfish toxins (DSTs) are a type of liposoluble toxins produced by toxic algae in the ocean, with main components of okadaic acid (OA), dinotricin-1 (DTX-1), and dinotricin-2 (DTX-2). They can accumulate in shellfish through food chain. Human consumption of toxic shellfish can have adverse effects on health. Therefore, conducting DSTS detection can effectively ensure food safety. Base on the principle of competitive enzyme-linked immunosorbent assay (ELISA), referring to the seed growth method, we prepared goldnano rods using gold nanoparticles (AuNPs), and conjugated them with okadaic acid antibody-horseradish peroxidase (OA-HRP) to form nanoprobes, which together established a novel ELISA technology of goldnano rods labeled OA-HRP. The technology presented significant detection advantages with a detection limit of 2.32 ng·mL^-1, a quantification limit of 2.97 ng·mL^-1, and a sample recovery rate of 85.2% to 117.8%. Both the intra-batch and inter-batch varia-tion coefficients were below 20.0%. The proposed method demonstrated high specificity for okadaic acid (OA), dinophysistoxin-1 (DTX-1), and dinophysistoxin-2 (DTX-2), with no cross-reactions observed against six other lipophilic toxins—azaspiracid-1, azaspiracid-2, and azaspiracid-3 (AZA-1, AZA-2, AZA-3), pectenotoxin-2 (PTX-2), yessotoxin (YTX), and homo-yessotoxin (hYTX). Moreover, it showed good correlation with the determination results of liquid chromatography-tandem mass spectrometry (LC-MS/MS). The goldnano rods labeled OA-HRP direct ELISA method established here significantly improved the detection sensitivity of DSTs, which could be used for rapid quantitative detection and analysis of DSTs in seafood, with significant application prospects.