Table of Content

10 July 2026, Volume 45 Issue 7

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Impact of typical heavy metal stress on photosynthesis and growth of marine diatom Phaeodactylum tricornutum.

LU Haiyue, LIU Xiang, XI Yimei, WANG Xinjie, WANG Shaofeng, ZENG Xiangfeng

2026, 45(7):  2113-2120.  doi:10.13292/j.1000-4890.202607.031

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The mechanisms by which heavy metal pollution impacts marine primary producers, particularly microalgal growth and photosynthesis, remain poorly understood. We investigated the effects of heavy metals (Cd, Ni, Sb, and Cr) on the marine diatom Phaeodactylum tricornutum using a controlled laboratory experiment. We evaluated algal density, chlorophyll content, fluorescence parameters, superoxide dismutase (SOD) activity, and energy metabolism under three concentrations of Cd²⁺, Sb³⁺, Ni²⁺, Cr⁶⁺ (1.16, 11.6, and 116 μmol·L). The results showed that P. tricornutum exhibited strong resilience to heavy metal stress, with algal density remaining stable across all treatments. Under Cd²⁺, Ni²⁺, and Sb³⁺ stress, the maximum electron transport rate (ETR_max) of algal cells decreased, while the initial quantum yield (α) increased, ultimately maintaining the stability of the chlorophyll fluorescence parameter (F_v/F_m). Meanwhile, heavy metals variably inhibited pigment synthesis and photosynthesis while significantly elevating SOD activity to mitigate oxidative stress. Despite these adaptive responses, photosynthetic efficiency remained consistently suppressed. Each heavy metal induced distinct intracellular effects. Cd²⁺ disrupted photosynthetic proteins. Ni²⁺ replaced Fe²⁺ in photosynthetic pigments. Sb³⁺ was enzymatically oxidized and extruded. Cr⁶⁺ was photoreduced before acting on proteins. These findings clarify the diverse physiological responses of marine primary producers to heavy metal stress, providing essential theoretical and experimental insights for assessing the ecological risks of heavy metal pollution on primary productivity in marine.





Leaching and release characteristics of thallium in weathered granite soils from southern Fujian: Insights from laboratory soil column simulations.

MA Jilong, PAN Shuxin, LI Shuaibei, QIU Zitai, WANG Qiugui, XIAO Enzong, XIAO Tangfu

2026, 45(7):  2121-2127.  doi:10.13292/j.1000-4890.202607.033

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We investigated the release characteristics of thallium (Tl) in soils under natural rainfall conditions within a granite geological high-background area, as well as the influences by agricultural activities and rainfall acidity. Two Tl-rich soil types with distinct land-use patterns (natural forest soil and pomelo orchard soil) in southern Fujian were selected. Dynamic soil column leaching experiments were conducted to simulate Tl release behaviors under varying pH conditions (pH 3.0, 4.5, and 5.4). Results showed that the initial Tl concentrations in the two soils were 2.21 and 2.59 mg·kg^-1 respectively, significantly exceeding the background value of Fujian Province (0.81 mg·kg^-1), indicating pronounced Tl enrichment due to geological high-background conditions. The leached Tl concentrations exhibited a consistent upward trend with increasing rainfall acidity. Notably, Tl concentrations in leachates from pomelo orchard soils (1.73±1.20 μg·L^-1) were significantly higher than those from natural forest soils (1.33±0.82 μg·L^-1) and exceeded the measured Tl levels in local surface water (0.58±0.11 μg·L^-1). These findings suggest that Tl in soils poses a risk of migration into surface water via rainfall leaching and further vertical infiltration into groundwater. Hydrogeochemical correlation analysis revealed significantly positive correlations between Tl and cations such as K, Ca, Mg, and Mn in leachates (P<0.05), indicating co-regulation of Tl release by multiple cations. Overall, this study demonstrates that Tl release and migration in soils under natural rainfall conditions are jointly controlled by rainfall pH and agricultural activities, with agricultural practices significantly intensifying Tl release rates and mobility. This study highlights potential risks of Tl contamination in groundwater and surface water within high geological background regions.





Effects of oil shale residue application on physicochemical properties and microbial biomass of sandy soil.

WANG Kai, LIU Chang, LYU Linyou, ZHANG Liang, JU Xiangdong

2026, 45(7):  2128-2136.  doi:10.13292/j.1000-4890.202607.014

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Due to the massive amount of residue produced during shale oil extraction, enhancing the resource utilization of oil shale residue is of critical importance. We conducted a field experiment with four treatments (0, 3, 6, and 9 kg·m^-2 oil shale residue added to sandy soil), following a randomized block design. We analyzed soil physicochemical properties, heavy metal contents, enzyme activities, and microbial biomasses under different treatments. The relationships between soil microbial biomass stoichiometry and soil properties were clarified, and the feasibility of improving sandy soil with oil shale residue was explored. The results showed that adding oil shale residue to sandy soil could improve soil structure and enhance soil fertility. The addition of 6 kg·m^-2 oil shale residue resulted in an increase of 90% and 29% in soil water content and porosity, respectively, while bulk density decreased by 7%. The contents of organic carbon, alkalinehydrolyzable nitrogen, and available phosphorus were increased by 31%, 26%, and 97%, respectively. The activities of catalase, urease, phosphatase and sucrase were enhanced by 59%, 86%, 18%, and 37%, respectively. Microbial biomass carbon, nitrogen, and phosphorus were increased by 18%, 64%, and 136%, respectively. However, compared with the addition of 6 kg·m^-2, the treatment of 9 kg·m^-2 oil shale residue addition significantly decreased soil urease, phosphatase, and sucrase enzyme activities as well as the carbon, nitrogen, and phosphorus contents in microbial biomass. Soil microbial biomass carbon, nitrogen and phosphorus were positively correlated with soil water content, porosity, organic carbon, alkaline-hydrolyzable nitrogen, available phosphorus, and catalase, urease, phosphatase and invertase activities. Soil organic carbon was the main factor affecting soil microbial biomass stoichiometry. Therefore, the optimal addition amount of oil shale residue is 6 kg·m^-2, which can enhance microbial activities, the activity of soil enzymes, nutrient transformation and cycling, and soil environment.



Rhizosphere soil characteristics and microbial community structure of dominant tree species in vegetation restoration areas of openpit mines.

ZHAO Liyun, LI Jiesan, WANG Ping, CHEN Hailiang, GUAN Ruizhe

2026, 45(7):  2137-2146.  doi:10.13292/j.1000-4890.202607.035

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Vegetation restoration is crucial for the ecological restoration of abandoned mines. To explore the effects of dominant tree species on soil physicochemical properties and microbial community structure during the restoration of open-pit mines, we collected soil samples from the rhizosphere of Juniperus formosana, Ligustrum lucidum, and Vernicia fordii in a recovered mine in Shaoxing, Zhejiang Province. We analyzed the impacts of different plant species on the improvement of soil quality. The results showed that pH of the rhizosphere soil of L. lucidum was the lowest, while soil water content was the highest. Silt soil content was the highest in the rhizosphere soil of J. formosana, with organic carbon, total nitrogen, and available nitrogen contents being higher than those of L. lucidum and V. fordii. There were no significant differences in acid phosphatase (ACP) activity of rhizosphere soils among the three tree species. The activities of N-acetyl-β-D-glucosidase (NAG), leucine aminopeptidase (LAP) and β-glucosidase in the rhizosphere soil of L. lucidum were significantly higher than those of J. formosana and V. fordii. The dominant fungal phyla in the rhizosphere soils of the three tree species were Basidiomycota and Ascomycota, while the dominant bacterial phyla were Pseudomonadota, Actinomycetota, and Acidobacteriota. The highest abundance of fungal operational taxonomic units (OTUs) was recorded in the rhizosphere soil of V. fordii, while the highest abundance of bacterial OTUs was recorded in the rhizosphere soil of L. lucidum. In contrast, the lowest abundance of bacterial OTUs and fungal OTUs were found in J. formosana. The Chao1, Shannon, and Simpson indices of bacterial and fungal diversity were the highest in the rhizosphere soil of V. fordii and the lowest in the rhizosphere soil of J. formosana. Soil water content, soil organic carbon, total nitrogen and available phosphorus affected bacterial community structure, while organic carbon, total nitrogen and available phosphorus affected soil fungal community structure. J. formosana was more conducive to the recovery of soil nutrients. The structure of the microbial community in rhizosphere soils of J. formosana was more stable though the diversity of the microbial community was lower. The specific Pseudomonadota recruited may contribute to soil remediation. V. fordii could recruit more soil microorganisms to improve soil microenvironment. These findings provide a theoretical basis for selecting appropriate tree species during mine revegetation and offer scientific reference for enhancing soil quality during the ecological restoration of mine.





Soil improvement characteristics and nutrient use strategy of Salix matsudana and Populus davidiana plantations in reclamation area of opencast coal mine.

LIU Chang, QI Yuetong, WANG Kai, LIU Yang, AN Yuan, SONG Haitao

2026, 45(7):  2147-2155.  doi:10.13292/j.1000-4890.202607.030

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To reveal the soil improvement effect and nutrient use strategy of forest plantations in opencast coal mine reclamation area, we examined the effects of Salix matsudana plantation and Populus davidiana plantation on soil physicochemical properties after 10 years of land reclamation, analyzed the concentrations of carbon (C), nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), zinc (Zn) and manganese (Mn) in each organ and leaf litter of those two tree species, and explored the nutrient resorption characteristics and influencing factors. The results showed that, compared to the unmanaged grassland, both S. matsudana and P. davidiana plantations increased soil water content, capillary porosity, and concentrations of organic C, total N, total P, total Ca, available N, and available P, while decreased soil bulk density, pH value, and concentrations of total K, total Mg, total Fe, total Zn, and total Mn. Nutrient resorption efficiencies of all examined elements in the two tree species were all greater than 0. The nutrient concentrations were usually higher in leaves, branches, and fine roots than those in trunks and coarse roots. P. davidiana had higher N resorption efficiency and N concentrations in organs and soils than S. matsudana. N resorption efficiency was significantly positively correlated with N concentration in mature leaves and soil. Therefore, planting S. matsudana and P. davidiana in reclamation area of opencast coal mine could enhance soil water retention, balance soil pH, increase concentrations of C, N, P and Ca, but reduce concentrations of K, Mg, Fe, Zn and Mn. P. davidiana had higher nutrient conservation and fertilization abilities compared to S. matsudana.





Influence of gravel content and infiltration volumes on the preferential flow of waste rock.

XIONG Shuzhen, LIANG Jiaxing, LUO Genhua, Lv Gang

2026, 45(7):  2156-2165.  doi:10.13292/j.1000-4890.202607.011

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Elucidating the development characteristics of the preferential flow within waste rock slopes is crucial for optimizing the reclamation plans and enhancing long-term stability. This study was conducted on the Hengtai Iron Mine in Fuxin City, Liaoning Province. By combining laboratory staining and tracer tests, the effects of gravel contents (65%, 75%, 85%) and infiltration volumes (90, 120, 150 mm) on preferential flow development were analyzed under the conditions of gravel particle size ranging from 2 to 7 cm. Using image processing technology, the preferential flow in gravel soil was evaluated through multiple indicators. The results showed that: (1) The gravel content had a dual regulatory effect on preferential flow development. Under the gravel content of 65%, preferential flow development was inhibited, characterized by the highest coefficient of variation in staining morphology but the lowest preferential flow ratio, length index, and total staining area ratio. As the gravel content increased, preferential flow development significantly intensified. The optimal preferential flow development characteristics were observed when gravel content reached 85%. (2) Infiltration volume was the key driving force for the development of preferential flow. Under different gravel contents, when the infiltration volume increased from 90 mm to 150 mm, both the preferential flow ratio and length index significantly increased, but the coefficient of variation of staining morphology significantly decreased (P<0.01). (3) The gravel content of 75% was a critical threshold for preferential flow development. When it was ≤75%, preferential flow development was mainly controlled by hydraulic drive, and when it was >75%, matrix action was dominant. (4) The preferential flow ratio, length index, and total dye coverage all exhibited a negative relationship with the coefficient of variation of staining morphology (P<0.01), collectively forming the comprehensive characteristics of preferential flow development. (5) Fourth-order polynomial function could accurately describe the nonlinear attenuation characteristics of preferential flows. In conclusion, a dual threshold regulation mechanism of gravel content and infiltration volume is formed during the development of preferential flow. Under the combined action of gravel content of 85% and infiltration volume of 150 mm, optimal water transport can be achieved, while 75% gravel content is the balance point for regulating hydraulic drive and matrix action.





Effects of oil sunflower (Helianthus tuberosus) planting on soil microorganisms and environmental factors in long-term heavy metal contaminated land.

GUO Jing, YANG Qili, ZHAO Zhixuan, WANG Fengting, TAI Hanyu, XU Duanping, WANG Dongli

2026, 45(7):  2166-2176.  doi:10.13292/j.1000-4890.202607.028

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Clarifying the effects of oil sunflower cultivation on soil environment and microbial community structure and function in historically heavy metal-contaminated fields can provide a scientific basis for green remediation of soil functionality. Using high-throughput sequencing of soil microbe and metagenomic analysis, we examined the differences in soil microbial community structure, gene functions, and environmental factors (soil heavy metals and physicochemical indicators) in long-term contaminated land by heavy metals from smelters under three oil sunflower planting conditions \[uncultivated wasteland (U_S), stunted-growth (SF_S) and vigorous-growth (SF_L)\], and explored the causes of such differences. Results showed that under the background of high Cd, Cu, Pb and Zn, oil sunflower planting significantly improved soil enzyme activities of urease, invertase, peroxidase and phosphatase, and soil microbial community structure significantly changed. Bacteria Pseudomonas, norank_f__Gemmatimonadaceae, norank_f__norank_o__Gaiellales, norank_f__norank_o__C0119, norank_f__SC-I-84, norank_f__norank_o__Acidobacteriales and fungi Fusarium, Penicillium, Solicoccozyma, unclassified_Fungi, unclassified_f__Archaeosporaceae dominated in U_S soil, while bacteria Microvirga, Pseudoxanthomonas and fungi unclassified_f__Pyronemataceae, unclassified_f__Sordariaceae were dominant genera in SF_L soil. The abundance ratios of dominant bacterial and fungal genera were negatively correlated with Pb, Cd, and TP, but positively correlated with pH, catalase, and urease. Meanwhile, metagenomics analysis showed that the gene functions of the main bacterial and fungal genera in the soil were dominated by transport and detoxification effects under the background of high heavy metal pollution. The Mantel-test network analysis of metagenomics and environmental factors revealed that oil sunflower cultivation elevated overall functional activity of soil microbes and improved soil quality under high heavy metal stress.





Progress in the study of influencing factors and action mechanism of chromium valence transformation in soil.

BAO Chenglong, LIU Genhong

2026, 45(7):  2177-2184. 

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chemical redox| organic matter complexation| microbial mediation| remediation strategy





The spatiotemporal variations of aboveground carbon storage of natural sandy Picea mongolica forests in the Hunshandake Sandy Land from 1975 to 2020.

XIA Jianxin, SONG Lining, CHEN Zhenju, SUN Yirong, YU Dongge, WANG Kaize, ZHENG Qingshan, ZHENG Xiao

2026, 45(7):  2185-2194.  doi:10.13292/j.1000-4890.202607.023

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The area of natural Picea mongolica forests in Baiyinaobao National Nature Reserve, the eastern edge of Hunshandake Sandy Land, was quantified based on the Landsat TM/ETM+ satellite remote sensing data from 1975, 1981, 1990, 2000, 2013 and 2020 combined with field investigation and laboratory experiments. A remote sensing estimation model for biomass was established, and then the biomass and carbon of natural Picea mongolica forests across different periods were inverted. Combined with the measured carbon content of organs (stem, branch, and leaf) of trees with different diameter classes, aboveground carbon storage and its spatiotemporal variation in the natural Picea mongolica forests across different periods were clarified. The results showed that: (1) The area of natural Picea mongolica forest in 1975, 1981, 1990, 2000, 2013 and 2020 was 1573.66, 1684.31, 1775.21, 1937.16, 1968.27, and 1999.69 hm², respectively, indicating that the area had continuously increased over the past 45 years. The natural Picea mongolica forest showed a spatial distribution pattern with more in the west and less in the east, with 95.1% being distributed in the western part of the study area. (2) The remote sensing estimation model for biomass of natural Picea mongolica forest is: y=7.556(1/b₅)²-6.9174(1/b₅)-20.917 (b₅ is the near-infrared band, R²=0.73). The biomass of the natural Picea mongolica forest was 7.53×10⁴, 7.82×10⁴, 8.36×10⁴, 9.17×10⁴, 9.70×10⁴ and 10.14×10⁴ t in  1975, 1981, 1990, 2000, 2013 and 2020, respectively. (3) The carbon content of different diameter classes and organs ranged from 501.10 g·kg^-1 to 545.09 g·kg^-1. The average carbon content of the aboveground part of Picea mongolica tree was 524.16 g·kg^-1 based on the weighted average method of the biomass of each organ. The carbon storage of natural Picea mongolica forest in 1975, 1981, 1990, 2000, 2013 and 2020 was 3.92×10⁴, 4.07×10⁴, 4.35×10⁴, 4.77×10⁴, 5.06×10⁴ and 5.27×10⁴ t, respectively. During 1975-2020, aboveground carbon storage of natural Picea mongolica forest increased by 1.35×10⁴ t, with a growth rate of 34.4%, indicating that Picea mongolica forest had a significant effect on carbon sequestration and sink enhancement, and also reflecting the gradual improvement of carbon sink capacity in the region. Spatially, the carbon storage showed significant heterogeneity (2.14-181.94 t·hm^-2), with the medium and low carbon storage grades (20-40 t·hm^-2) being the main ones (with the largest proportion), but the area of mature forests with high carbon storage grades (≥40 t·hm^-2) increased significantly over time, indicating that the regional carbon accumulation was tending towards a stable growth stage. The area expansion of natural Picea mongolica forest and the increases in carbon storage have significantly enhanced the regional carbon sink capacity. The dynamics and spatial distribution characteristics of its carbon storage provide a scientific basis and data support for the protection and management of natural forests as well as for the achievement of China’s carbon neutrality goals.





Estimation of forest biomass carbon storage and sequestration potential in Liaoning Province based on plot survey and continuous inventory.

JING Chunlin, ZHOU Wangming, XU Peng, ZHANG Hengming, GU Weiwei, ZHOU Yongbin, WEI Yawei

2026, 45(7):  2195-2203.  doi:10.13292/j.1000-4890.202606.023

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As a dominant component of terrestrial ecosystems, forests play a crucial role in carbon storage and sequestration. It is of important guiding significance to accurately estimate forest carbon storage and sequestration potential for better achieving China’s “dual carbon” goals. Using 923 forest plots data across Liaoning Province, we established stand-level databases of the biomass and volume for main forest types, and constructed the biomass-volume conversion equations of 12 forest types in the region. These equations were further combined with information from nine consecutive national forest resource inventories (1973-2018) and a grey prediction model to estimate forest biomass carbon storage and carbon sequestration potential in Liaoning Province. Results showed that compared with the period of 1973-1976, forest biomass carbon storage and carbon density in 2014-2018 increased by 165.53% and 57.86%, being 152.92 Tg C and 35.93 Mg C·hm^-2, respectively. Across age classes, biomass carbon storage of middle-aged and young forests contributed the largest proportion, accounting for more than 53.87% of the total. Among forest types, the mixed broad-leaved forests held the highest biomass carbon storage, comprising more than 40.96% to the total. Regionally, the eastern part of Liaoning contributed the most proportion, accounting 72.33% of the total forest biomass carbon storage. By 2035 and 2060, forest biomass carbon storage is projected to reach 262.06-275.67 and 586.34-592.23 Tg C, respectively, highlighting the region’s considerable biomass carbon sequestration potential. Our results realized the conversion of biomass carbon storage from the individual tree to stand and regional scales, laying a foundation for the management of forest ecosystems and the achievement of the “dual carbon” goals in Liaoning Province, and providing a reference for the accurate estimation of forest biomass carbon storage in other regions of China.





Distribution pattern of plant diversity in the Tarim River basin and its influencing factors.

YANG Yaqin, TIAN Aolei, QING Xiandong, JIANG Jinfeng, HALIK müt

2026, 45(7):  2204-2211.  doi:10.13292/j.1000-4890.202607.025

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Understanding plant diversity in the Tarim River Basin is of great significance for the assessment of regional ecological restoration. However, current studies mostly focused on vegetation restoration in the downstream ecological water conveyance area, lacking a comprehensive analysis of the distribution pattern of plant diversity and its influencing factors across the entire basin. In this study, combining field survey with the measurement of soil physicochemical properties, we investigated the distribution patterns of plant diversity and its influencing factors along the Tarim River. The results showed that: (1) Among the seven plots (50 m×50 m) established along the upper, middle, and lower reaches, a total of 13 plant species, belonging to 13 genera and 8 families, were recorded. The overall plant diversity distribution followed a pattern of upper reaches > middle reaches > lower reaches. Plots near the Daxihaizi Reservoir in the lower reaches exhibited relatively high plant diversity indices. (2) Results of redundancy analysis (RDA) and canonical correlation analysis (CCA) revealed that soil physicochemical properties directly governed the distribution of plant diversity. The mean variation of soil water content was consistent with the change trend of plant diversity. Except for total soil phosphorus (TP), the contents of total salt (TS), total carbon (TC), and total nitrogen (TN) exhibited similar variation patterns. (3) The artificial ecological water conveyance project effectively improved soil environment in the lower reaches of the Tarim River and promoted the restoration of plant diversity in the basin, while also highlighted the spatial imbalance of ecological restoration in the upper, middle, and lower reaches. This study deepens the understanding of the distribution pattern of plant diversity and its influencing factors in the Tarim River Basin, providing a theoretical basis for the effectiveness evaluation of the artificial ecological water conveyance scheme in the lower reaches.





The effects of snow cover removal on soil nitrogen mineralization in subalpine forests of western Sichuan.

YANG Fan, LIU Yuwei, TAN Bo, LI Han, YANG Kaijun

2026, 45(7):  2212-2221.  doi:10.13292/j.1000-4890.202607.020

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Soil nitrogen mineralization is a key component of nutrient cycling in forest ecosystems. The variations of winter snow cover in alpine forests, driven by global climate warming, can significantly affect soil nitrogen mineralization by altering surface micro-environmental conditions. In this study, we conducted an in-situ experiment that compared natural snow input (control) and snow removal treatment in a subalpine Abies faxoniana forest in western Sichuan. We investigated the effects of snow removal on soil micro-environmental conditions, organic and inorganic nitrogen contents, and nitrogen mineralization rates. The results showed that snow removal significantly increased the frequency of freeze-thaw cycles in the soil organic layer and reduced the water content in the soil organic layer and mineral soil layer by 11.86% and 16.24%, respectively. It also induced marked temperature fluctuations in the organic layer during winter and notably decreased soil temperature during the growing season. Snow removal resulted in significant increases in total nitrogen (TN), microbial biomass nitrogen (MBN), and dissolved organic nitrogen (DON) in the soil organic layer by 96.23%, 82.72%, and 210.96%, respectively. In contrast, TN and MBN contents in the mineral soil layer decreased by 9.73% and 64.97%, respectively. Moreover, snow removal enhanced net nitrogen mineralization rates by 248.27% in the organic layer and by 4.94% in the mineral layer. These effects suggest that snow removal affects soil nitrogen mineralization process in the organic layer by altering soil temperature and regulating the transformation of organic nitrogen to inorganic nitrogen. However, in the mineral layer, soil nitrogen mineralization is primarily promoted by increased organic nitrogen input. In summary, snow cover changes influence nitrogen mineralization in subalpine forest soils by modulating both temperature regimes and substrate availability. These findings contribute to a better understanding of how subalpine forest ecosystem processes respond to global climate change.





Allocation patterns and influencing factors of vegetation and soil carbon density in the river wetland in Lanzhou section of the Yellow River.

WANG Enqi, ZHAO Chengzhang, ZHAO Ziyi, SHI Wenhao, ZHANG Xinyue

2026, 45(7):  2222-2229.  doi:10.13292/j.1000-4890.202607.017

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Understanding the distribution patterns of carbon density and influencing factors of wetlands is conducive to revealing the influence mechanism of wetland eco-hydrological processes on carbon sequestration. Based on variations in groundwater levels and the characteristics of plant community distribution, three habitats in the riparian wetland along the Yellow River in Yan’erwan Wetland Park of Lanzhou City were established sequentially from the riverside to the higher-elevation shoal: waterside zone, transition zone, and edge zone. The spatial distribution of carbon density of wetlands and its influencing factors were examined by community investigation. The results showed that from the waterside zone to the edge zone, groundwater level declined, soil water content decreased, and biomass, coverage and density of plant community decreased from 3409.51 g·m^-2, 97.84%, and 221.84 bunch·m^-2 to 1396.85 g·m^-2, 96.34%, and 149.00 bunch·m^-2, respectively. Ecosystem carbon density, vegetation carbon density, stem carbon density, and leaf carbon density decreased from 96.57, 14.26, 4.11, and 3.31 t·hm^-2 to 61.98, 5.55, 1.32, and 0.99 t·hm^-2, respectively. The proportions of stem and leaf carbon density declined from 28.79% and 23.24% to 23.80% and 17.77%, respectively, while the proportions of root carbon density and soil carbon density increased from 47.97% and 85.23% to 58.43% and 91.05%, respectively. There were significant differences in soil organic carbon content and carbon density across different habitats. The carbon density of the whole ecosystem and that of the vegetation and soil component were highly significantly positively correlated with community height, biomass, soil organic carbon content, and soil moisture (P<0.01). In summary, water level fluctuations among habitats significantly influence vegetation and soil carbon density in river wetlands.





Changes in the concentrations of non-structural carbohydrates and C, N, P, and K in leaves of Alhagi camelorum following root severance and rewatering.

LIU Xiyue, XIAO Bowen, HUANG Caibian, LI Xiangyi, WANG Xin, ZENG Fanjiang

2026, 45(7):  2230-2239.  doi:10.13292/j.1000-4890.202607.019

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To investigate the responses of carbon and nutrients in leaves during regeneration of Alhagi camelorum following root severance, a field experiment was conducted at the southern margin of the Taklimakan Desert. There were three treatments, including natural growth without disturbance (CK), root severance without rewatering (DG), and root severance followed by rewatering (DW). Leaf soluble sugar and starch contents, together with carbon (C), nitrogen (N), phosphorus (P), and potassium (K) contents were measured at different time intervals after root severance. We analyzed variations in non-structural carbohydrates (NSC) and the stoichiometric ratios of C, N, and P throughout the regeneration process, and examined the correlations of those nutrients. The results showed that during the early stage after root severance (days 1-3), the starch and NSC contents in the leaves under both DG and DW treatments significantly decreased, while the soluble sugar/starch ratio increased. The C, N, P, and K contents remained stable. In the mid-stage (days 5-10), the contents of NSC and its components tended to stabilize under DG treatment, whereas N and P contents showed a decreasing trend under DW treatment. In the late stage (days 25-50), new shoot sprouted from A. camelorum in the DW treatment, and the soluble sugar, N, P, and K contents in the leaves decreased significantly, accompanied by increases in N∶P, C∶N, and C∶P ratios, indicating pronounced nutrient resorption from senescing leaves to new shoots. Under DW treatment, leaf NSC content was significantly and positively correlated with C, N, and K contents, indicating the synergistic coupling among NSC and key nutrients during A. camelorum regeneration. These findings suggest that under root severance with subsequent rewatering, soluble sugars together with N, P, and K stored in the old leaves can be actively remobilized to support the growth of new shoots. The results provide a theoretical basis for vegetation restoration strategies involving root severance-based transplantation of A. camelorum.





Spatiotemporal variation of carbon and water use efficiency and their responses to climatic factors in northern Guangdong.

LIU Yanqun, DU Yaodong, DENG Yujiao, HUANG Guanrong, WANG Min

2026, 45(7):  2240-2248.  doi:10.13292/j.1000-4890.202607.005

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Carbon use efficiency (CUE) and water use efficiency (WUE) of vegetation are critical variables for characterizing the coupled carbon-water cycling in terrestrial ecosystems. Based on satellite remote sensing and ground observation data, we used linear regression analysis, stability analysis, trend analysis, Mann-Kendall test, Hurst index, and partial correlation analysis to investigate the spatiotemporal variations of vegetation CUE and WUE in northern Guangdong from 2000 to 2024 and their responses to climatic factors, aiming to provide a theoretical basis for understanding the coupling mechanisms of carbon-water cycling in this region. The results showed that: (1) During 2000-2024, the mean CUE and WUE in northern Guangdong were 0.509 and 0.913 g C·m^-2·mm^-1, respectively, exhibiting a spatial pattern of lower values in the northwest and higher values in the southeast. CUE displayed a significant decreasing trend, whereas the decline in WUE was statistically insignificant. (2) Stability analysis indicated predominantly low or relatively low fluctuations in both CUE and WUE across most areas. (3) CUE degradation was widespread. In contrast, improvement areas exceeded degradation areas for WUE. Persistence analysis suggested that decreasing CUE trends would continue in most regions, while projected increases in WUE would exceed decreases. (4) Temperature exerted stronger control over CUE than precipitation and drought, whereas precipitation dominated WUE variation. Increasing temperatures suppressed CUE, while rising precipitation reduced WUE. Drought tended to enhance both CUE and WUE.





The characteristics and influencing factors of dew condensation in the middle reaches of the Yarlung Tsangpo River valley.

JIA Zhifeng, LIU Hao, LI Ge, ZHAO Wei

2026, 45(7):  2249-2260.  doi:10.13292/j.1000-4890.202607.037

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Dew is an important source of water for plant growth in arid areas. Therefore, exploring its generation process is of great significance for the construction of ecological restoration projects in arid areas. To clarify the characteristics and influencing factors of dew occurrence in the middle reaches of the Yarlung Zangbo River valley, an in situ dew observation experiment at 0.2 and 1 m height above ground using leaf wetness sensors was carried out in Qushui County, Lhasa City from September 2023 to August 2024. The results showed that: (1) During the monitoring period, the cumulative dew at 0.2 and 1 m height was 14.21 and 20.84 mm, respectively. Dew occurred mainly in autumn, followed by summer. Its main occurrence period was from 23:00 to 08:00 in the next morning, with the peak occurring from 06:30 to 08:00 in the early morning. (2) When the relative humidity was greater than 60% at 0.2 m height, the temperature dew point difference was less than 8 ℃, the wind speed at 2 m was less than 2.8 m·s^-1, and the wind direction was southeast, these conditions were conducive to dew formation. (3) At 0.2 and 1 m, the highest monthly ratio of dew to rain were found all in September, which was up to 152.02% and 226.26%, respectively. (4) When the daily dew amount reached its peak, soil moisture increased in the range of 1.23% to 3.57% at soil surface and 0.19% to 3.1% at the 5 cm depth. These results could provide a theoretical basis for the collection and utilization of dew and ecological restoration in arid areas.





Effects of soil water content on growth and physiological traits of Typha orientalis. 

LIU Yang, TANG Siwen, LIN Shengqing, LI Ruoxun, HUANG Jia, LUO Shanshan, CAO Yun

2026, 45(7):  2261-2267.  doi:10.13292/j.1000-4890.202607.012

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Soil water content could influence the growth and physiological traits of wetland plants. To investigate the growth and physiological conditions of Typha orientalis in response to the variations of soil moisture, we established seven treatments with soil water contents of 9%, 14%, 19%, 22%, 33%, 36% and 38%. The growth and physiological indicators of T. orientalis were measured. The results showed that: (1) The growth of T. orientalis was sensitive to changes in soil water content. Based on a comprehensive analysis of growth and physiological indicators, the suitable soil water content for T. orientalis ranged from 22% to 36%. The maximum plant height and basal diameter were observed at 36% soil water content, reaching 184.20 cm and 12.74 mm, respectively. Moreover, T. orientalis tolerated soil water contents of 9% for 36 days and 14% for 114 days, indicating a strong short-term drought tolerance. (2) Total biomass of T. orientalis initially increased and then decreased with increasing soil water content, reaching a maximum of 8.95 g·plant^-1 on day 90 in the treatment of 36% soil water content. (3) Chlorophyll a content in T. orientalis reached its maximum value of 1.76 mg·g^-1 on day 30 under 33% soil water content, whereas chlorophyll b and carotenoid contents reached their maximum values of 0.62 and 0.27 mg·g^-1, respectively, on day 60 under 22% and 38% soil water content. (4) On day 120, peroxidase (POD) activity reached a maximum of 36.61 U·g^-1·min^-1 in the 38% soil water content treatment, while superoxide dismutase (SOD) and catalase (CAT) activities peaked under 36% and 33% soil water content, with values of 188.32 U·g^-1 and 46.01 U·g^-1·min^-1, respectively. In conclusion, the soil water content of 22% to 36% is most suitable for the growth of T. orientalis. These findings are helpful for reasonably regulating soil water content during wetland ecological restoration, promoting the healthy growth of T. orientalis, and thereby maintaining the health of wetland ecosystems.





Effects of stover mulch and no-tillage on maize root traits, yield and soil physical properties: A meta-analysis.

MO Xiaofan, LU Jiayu, LIN Junjie, LAN Guoxin, WANG Mingli

2026, 45(7):  2268-2275.  doi:10.13292/j.1000-4890.202607.002

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No-tillage with stover mulching (NTS) is a conservation agriculture practice, which can enhance soil structure, improve soil fertility, and sustain agroecosystem functions. However, the differential effects of no-tillage and stover mulching on maize yield and root-soil interactions remain unclear. Here, we conducted a meta-analysis of 65 peer-reviewed papers to systematically evaluate the impacts of no-tillage (NT) \[NT vs conventional tillage (CT)\] and no-tillage with stover mulching (NTS vs NT or CT) on maize yield, soil properties, and root traits. NT significantly reduced maize yield by 7.4% compared to CT, while NTS increased yield by 6.1% relative to NT, achieving the same yield as CT. NT significantly increased soil bulk density (BD, 3.6%) and penetration resistance (PR, 17.7%) compared to CT, while NTS significantly alleviated these adverse effects with reducing PR by 12.4% compared to NT, and increased soil moisture content (SMC) by 10.3% and 7.0% over NT and CT, respectively. NT significantly decreased root length density, root biomass density, and root surface area density by 10.0%, 10.6%, and 20.6% compared to CT, whereas NTS significantly enhanced root biomass by 12.0% and 15.6% over NT and CT, respectively. NTS could maintain maize yield through optimizing BD, PR, and SMC, and promoting root length density. These findings indicate that stover mulching counteracts the negative effects of NT by improving topsoil physical properties and optimizing root morphological traits, thereby enhancing nutrient uptake efficiency. This study provides critical insights for optimizing conservation practices in maize production systems.








Effects of maize/alfalfa intercropping on microbial communities in cinnamon soil.

LIANG Siwei, ZHOU Huanan, DU Guijuan, CAI Qian, LI Na, YANG Shu, ZHANG Shiyu, LOU Yisheng, LIU Xiaotong, CUI Shuyan, SUN Zhanxiang

2026, 45(7):  2276-2284.  doi:10.13292/j.1000-4890.202607.007

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Maize/alfalfa intercropping serves as an important practice for enhancing soil functions, with significant potential in improving soil structure and nutrient cycling. However, it is unclear how such intercropping system regulates microbial community structure and interannual dynamic succession in cinnamon soil regions, particularly about the long-term effects of different row ratio configurations. We investigated the effects and interannual stability of different maize/alfalfa row ratio configurations in the cinnamon soil region of northwestern Liaoning. There were five planting treatments in a field experiment, including maize monoculture (SM), alfalfa monoculture (SA), maize-2-rows/alfalfa-2-rows intercropping (M2A2), maize-2-rows/alfalfa-4-rows intercropping (M2A4), and maize-4-rows/alfalfa-4-rows intercropping (M4A4). High-throughput sequencing was employed to analyze soil microbial diversity and community structure. The results showed that maize/alfalfa intercropping significantly increased microbial diversity and altered the community structure of soil fungi, while there was no significant variation in soil bacterial community composition among treatments. The maize/alfalfa intercropping (M2A2 and M4A4) significantly enhanced soil microbial diversity by improving nitrogen availability and other physicochemical properties. In general, this study provides a theoretical basis for optimizing planting patterns to enhance farmland ecological functions in northwestern Liaoning.








The impact of intercropping maize with different crops on the population dynamics of pests and their natural enemies.

YANG Shaowu, WANG Wei, LIU Lingling, LI Yiru, QI Ying, LI Lifang, LIU Jiani, YU Lei

2026, 45(7):  2285-2294.  doi:10.13292/j.1000-4890.202607.010

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Intercropping patterns shape insect community structure and contribute to the suppression of insect pests. Based on systematic field investigations, we examined the changes in species composition and population dynamics of major insect pests and their natural enemies in maize fields intercropped with different companion crops. The aim of this study was to provide a scientific basis for ecological pest management in maize fields. The results showed that the major pests were Ostrinia furnacalis, Pseudaletia separata, Spodoptera litura, and Spodoptera frugiperda. The dominant natural enemies included Orius similis, Harmonia axyridis, Trichogramma chilonis, and Trichogramma ostriniae. Compared to maize monoculture, the abundance of O. furnacalis and P. separata was lower (with peak <45 individuals per 100 plants), while the abundance of T. chilonis and T. ostriniae was higher (with peak > 40 individuals per board) in the konjacmaize intercropping system. A high niche overlap index was observed between O. similis and S. litura (0.962), and the population dynamics of the two insect species were significantly positively correlated. In shallot-maize fields, the peak density of S. litura population was suppressed. Additionally, there was a strong niche overlap between T. ostriniae and O. furnacalis (0.971) and between H. axyridis and P. separata (0.969). There was significant positive correlation between the populations of T. ostriniae and O. furnacalis, as well as H. axyridis and P. separata. In pepper-maize intercropping system, peak abundances of T. chilonis and T. ostriniae were relatively higher (exceeding 40 individuals per board). There were higher niche overlaps between T. chilonis and S. litura (0.891), between T. ostriniae and O. furnacalis (0.921), and between H. axyridis and P. separata (0.933). There was significant positive correlation between the populations of T. chilonis and S. litura, T. ostriniae and O. furnacalis, as well as H. axyridis and P. separata. These results demonstrate that intercropping maize with konjac, shallot, or pepper can effectively reduce pest pressure and enhance the regulatory efficacy of natural enemies. Thus, these systems are recommended as effective ecological planting patterns for sustainable pest management in maize fields.





Inhibition mechanisms of high-dose imidacloprid stress on photosynthesis in Medicago sativa.

LIU Siyu, WANG Yumiao, LI Shuang, WANG Guangyang, FAN Shugao, YIN Yanling

2026, 45(7):  2295-2304.  doi:10.13292/j.1000-4890.202607.027

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To investigate the mechanisms underlying photosynthetic damage in leaves of alfalfa (Medicago sativa) induced by rhizospheric residues of imidacloprid (IMI)-a neonicotinoid insecticide, alfalfa roots were exposed to Hoagland nutrient solutions containing different concentrations of IMI. Based on the responses of plant growth and physiological variables to IMI stress, an IMI stress concentration of 2 mM was determined. The inhibitory effects of high-dose IMI stress on photosynthesis of alfalfa were then analyzed using chlorophyll fluorescence kinetics. Rhizosphere IMI stress caused leaf necrosis and oxidative stress in alfalfa, leading to photosynthetic inhibition, as evidenced by chloroplast structural damage, a decline in photosynthetic potential, and block of the fluorescence rise in the J-P phase of the chlorophyll fluorescence induction curve (OJIP). Further JIP testing indicated that the photosynthetic inhibition induced by high-dose IMI stress might be associated with impaired electron transport on both the donor and acceptor sides of photosystem Ⅱ (PSⅡ). IMI stress reduced energy available for electron transport (ET₀/CS₀, ET₀/RC) and increased energy dissipation (DI₀/CS₀, DI₀/RC). Fluorescence quenching analysis confirmed that high-dose IMI inhibited photochemical efficiency, triggered nonphotochemical quenching, and caused photodamage. These findings revealed the mechanism by which high-dose IMI in the rhizosphere significantly inhibits photosynthesis of alfalfa by impairing electron transport in PSⅡ, providing new insights into the environmental risks of neonicotinoid insecticides.





Effects of low-temperature stress on the phenotypic characteristics of tea plants and leaf quality, and the development of frost-damage grading indices.

LI Shirui, LIAO Bijun, CHEN Zunjie, LI Xin, SUN Rui, LI Zhengzhen

2026, 45(7):  2305-2312.  doi:10.13292/j.1000-4890.202603.008

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Understanding frost damage level for different tea cultivars is of great significance for the precise forecasting of spring frost damage to tea plants. In this study, pot-grown “Longjing 43” and “Baiye No. 1” tea plants were subjected to five low-temperature treatments (4, 2, 0, -2, -4 ℃） and 25 ℃ (control) and eight low-temperature duration treatments (0.5, 1, 2, 3, 6, 9, 12, and 24 h) during the spring bud sprouting stage in an artificial climate chamber. The effects of low-temperature stress on the phenotypic characteristics and tea quality of the plants were examined. Based on a comprehensive consideration of minimum temperature and exposure duration, frost damage grading indices for “Longjing 43” and “Baiye No. 1” were established. The results showed that: (1) there were significant differences in phenotypic characteristics between “Longjing 43” and “Baiye No. 1” after lowtemperature stress. Starting from 0 ℃, as temperature decreased and the exposure duration increased, the phenotypic changes in “Baiye No. 1” were noticeably more severe than those in “Longjing 43”, indicating that “Longjing 43” had stronger cold resistance than “Baiye No. 1”. (2) Under low-temperature stress, tea quality of “Longjing 43” exhibited distinct change patterns. At temperatures of 0 ℃ and above, polyphenol content showed a slow declining trend with increasing exposure time. When the temperature dropped below 0 ℃, the content generally increased. In contrast, amino acid content showed a slow increasing trend at temperature above 0 ℃, while at temperatures below 0 ℃ it initially increased, then declined, and subsequently increased slowly again. (3) Using hourly temperature data from tea garden microclimate stations in 2016 and from 2021 to 2022, the frost damage grading indices for “Longjing 43” and “Baiye No. 1” were validated, achieving accuracy of 100% and 88.89%, respectively.





Effects of mineral conditioner on soil quality in sloping pepper farmland.

ZHANG Yuru, PENG Zhihong, TANG Xiwen, ZHANG Xinwen, ZHANG Jie, LUO Xianghong, CHU Fei, LIU Lili, ZHOU Xuan

2026, 45(7):  2313-2320.  doi:10.13292/j.1000-4890.202607.015

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To investigate the effects of mineral conditioner on soil fertility in sloping pepper farmland, a field plot experiment was set up in Xiangtan, Hunan Province. There were five treatments, including conventional fertilization (CF), and CF combined with mineral conditioner at rates of 750 (T1), 1500 (T2), 2250 (T3), and 3000 kg·hm^-2 (T4). We examined the effects of different application rates of mineral conditioner on soil pH, cation exchange capacity (CEC), soil organic matter (SOM), nutrient content, and enzyme activities. Compared with CF, T2, T3, and T4 treatments significantly increased pepper yield and economic benefits by 39.3% to 51.7% and 60.0% to 77.6%, respectively. T4 treatment significantly increased soil pH by 15.2%. T3 treatment significantly increased soil available phosphorus content by 41.5% and available potassium content by 28.9%. T2 treatment significantly increased soil urease activity by 17.7%, while T3 treatment significantly increased soil acid phosphatase activity by 7.2%. Compared with CF, T4 treatment significantly increased soil integrated fertility index (IFI) by 16.4%. Pepper yield was significantly positively correlated with IFI, soil CEC and sucrose enzyme activity, soil pH, hydrolyzable nitrogen and available potassium contents. Principal component analysis (PCA) indicated that the contents of soil available nutrients, pH value, CEC, and sucrose enzyme activity were the main factors influencing soil quality and pepper yield. In conclusion, appropriate application of mineral conditioner could effectively alleviate soil acidification, increase CEC, enhance the contents of available phosphorus and available potassium, improve soil urease and acid phosphatase activities, and elevate overall soil fertility. In particular, the treatment with 2250 kg·hm^-2 mineral conditioner showed better improvement effect.





Effects of leaf picking in different periods on microclimate and fruit quality of wine grape.

MA Li, WANG Jing, HU Hongyuan, YANG Yang, JIANG Linlin, LI Hongying, ZHANG Xiaoyu

2026, 45(7):  2321-2331.  doi:10.13292/j.1000-4890.202607.008

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Clarifying the impacts of leaf picking in different periods on the microclimate around grape clusters and the berry quality components can provide a basis for refining vineyard management practices and producing high-quality wine grapes. An experiment was conducted in the eastern foothills of the Helan Mountains using Vitis vinifera “Cabernet Sauvignon”, a major wine grape variety. Leaf picking was performed at two post-veraison stages: the third week (T3) and the fifth week (T5) after veraison. At each stage, there were three treatments: removal of leaves on the east side of the canopy (E), on the west side (W), or on both sides (EW). The results showed that: (1) From veraison to maturity, air temperature around grape clusters and berry temperature showed a fluctuating decline. Leaf removal generally increased cluster-zone air temperature, berry temperature, and the level of photosynthetically active radiation (PAR) measured linearly across clusters. Compared to the control (CK), the accumulated temperature around grape clusters and on berry across different treatments increased by 19.9-29.9 ℃·d and 43.1-54.7 ℃·d on average and linear PAR by an average of 1689.3 μmol·m^-2·s^-1. (2) Leaf picking significantly increased the content of soluble solids, reducing sugars, and pH, thereby accelerating sugar accumulation. It significantly decreased titratable acidity, but promoted the decomposition of malic acid and tartaric acid, increased the citric acid content, and enhanced the accumulation of total phenols and anthocyanins. The effects on sugar and acid metabolism were more pronounced when leaf picking was performed at T3 compared to T5. (3) A comprehensive evaluation using the TOPSIS model based on the entropy weight method scored the highest under the east-side leaf picking treatment at T3, indicating the highest fruit quality. (4) For north-south oriented vineyards in the eastern foothills of Helan Mountains, a canopy management strategy involving east-side leaf picking in the third week after veraison is recommended. This approach effectively regulates key quality components, helps reduce disease incidence, and improves final grape quality.



Ecological suitable planting regions and key ecological factors of medicinal plant Ardisia crispa.

JIANG Jinxiang, HUANG Anling, REN Zhiqin, YANG Rong, XU Chaojuan, WEI Shenghua, WANG Zhiwei

2026, 45(7):  2332-2340.  doi:10.13292/j.1000-4890.202606.016

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The ecological suitability of Ardisia crispa in China was assessed using the maximum entropy model (MaxEnt) based on 507 distribution records and 118 ecological factors. We assessed the key ecological factors and optimal ranges of A. crispa through jackknife test, factor contribution rate, and response curve, aiming to provide scientific guidance for the ecological planting. The results showed that the ecological suitable regions of A. crispa were primarily distributed in Guizhou, Chongqing, Hunan, Guangxi, Sichuan, and Hubei provinces. The highly and moderately suitable regions were extensively concentrated in northern Guizhou-southern Chongqing-northwestern Hunan-southwestern Hubei, and northern Guangxi-southeastern Guizhou-southwestern Hunan. Among numerous ecological factors, solar radiation demonstrated the highest cumulative contribution rate (56.46%), followed by vegetation (17.03%), precipitation (13.45%), soil (8.89%), temperature (2.65%), and topography (1.51%). Thereinto, solar radiation in March and June (Srad_03, Srad_06), precipitation in the warmest quarter (Bio_18), and evergreen broadleaved forest (Class_02) were the key factors influencing the suitability of A. crispa in China. Based on those findings, it is recommended to establish two key ecological planting regions for A. crispa. The first one encompassed northern Guizhou-southern Chongqing-northwestern Hunan-southwestern Hubei, and the second one comprised northern Guangxi-southeastern Guizhou-southwestern Hunan. Solar radiation should be given priority in the planting process, followed by vegetation, precipitation, soil, temperature, and topography. The range of key ecological factors Srad_03, Srad_06, Bio_18 and Class_02 should be controlled between 7841.70-11934.35 kJ·m^-2·d^-1 (optimal 11115.82 kJ·m^-2·d^-1), 14870.77-17084.56 kJ·m^-2·d^-1 (15016.41 kJ·m^-2·d^-1), 477.52-692.89 mm (602.21 mm) and 2.48%-42.08% (8.24%), respectively.





Bird diversity and population dynamics in Qinhuangdao based on bird-banding data.

ZHANG Jian, CAO Zhenchi, LI Jia, YANG Jinguang, LIU Dongping

2026, 45(7):  2341-2347.  doi:10.13292/j.1000-4890.202607.024

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Over the past few decades, the populations of many bird species along the East Asian-Australasian Flyway have shown a trend of decline. In this study, we investigated whether changes in the diversity and population of migratory birds were detectable at a key stopover site on the East Asian Flyway, Qinhuangdao Bird Banding Station, Hebei Province, China, based on bird-banding data collected between 2004 and 2020. During the 17-year period, a total of 209393 birds of 225 species were banded. Among these birds, there were 15642 individuals (7.5% of the total) representing 29 national key protected species (12.9% of the total banded species). The Shannon diversity index showed a significant trend of decrease, while the evenness index and dominance index remained unchanged, indicating that a reduction in species richness was the main cause of the decline in diversity. An analysis of the two predominant national key protected species banded, i.e., the Siberian Rubythroat (Calliope calliope) and the Chestnut-flanked White-eye (Zosterops erythropleurus), revealed that their numbers stopping over at Qinhuangdao were relatively stable. Both species showed significantly different migration process between spring and autumn, with the spring migration being much faster and more concentrated. Over the 17 years, there was no effect of temperature on spring migration phenology in both species. The decline in the diversity of banded birds in Qinhuangdao is, on one hand, a result of the overall changes in bird communities along the flyway, and on the other hand, may be related to the decrease in net capture rates caused by vegetation growth at the netting sites. Appropriate thinning and canopy pruning of vegetation at the netting sites should be carried out in the future to maintain the structural heterogeneity of the shrub-arbor ecotone, thereby providing suitable habitats for a variety of bird species.





Bird and mammal diversity and seasonal spatial distribution in Laoshan forest area of northern Shaanxi based on automatic camera monitoring.

LIU Yaoguo, ZENG Ke, SHI Lina, WANG Ru, DANG Cuiying, MA Mimi, NAN Bowen, XU Shicai, ZHU Mengyan

2026, 45(7):  2348-2357.  doi:10.13292/j.1000-4890.202607.001

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The monitoring and analysis of regional species diversity constitute crucial bases for the formulation of conservation strategies. To evaluate the seasonal variations of bird and mammal resources in the Laoshan forest area of northern Shaanxi Province, we employed camera traps to conduct a survey on bird and mammal resource diversity, compiled wildlife inventory, and analyzed the relative abundance of each species. We examined the spatial patterns of biodiversity across different seasons using the inverse distance weighted method, delineated priority areas for forest conservation through overlay analysis, and analyzed the impacts of human activities using Human Influence Index. Between January 2020 and April 2023, a total of 19 bird species from 6 orders and 11 families and 12 mammal species from 4 orders and 8 families were recorded. Among those species, two species are listed as Class I Nationally Protected Species-the leopard (Panthera pardus) and the Brown Eared Pheasant (Crossoptilon mantchuricum), with five species under Class Ⅱ Nationally Protected Species. The discovery of a population of North Chinese leopards (Panthera pardus japonensis) within the forest area represents the northernmost recorded distribution in Shaanxi Province. The Brown Eared Pheasant exhibited the highest relative abundance among birds, indicating an ongoing northward expansion of the species in Shaanxi. Biodiversity in forests displayed a spatial pattern characterized by higher diversity at the periphery and lower diversity in the center. The warm season (June-August) showed a broader area of high biodiversity compared to the cold season (December-February), suggesting that the eastern and southwestern regions should be designated as priority areas for biodiversity conservation. Human activities negatively impacted the spatial distribution of biodiversity across the forest area. Our findings provide reliable evidence for the planning of wildlife nature reserves in the Laoshan forest area. We recommend the establishment of ecological corridors within the region to promote the healthy development of biodiversity.





The distribution pattern of suitable habitats and the optimization of ecological network for Crossoptilon mantchuricum.

ZHAO Pengyu, ZHANG Shuhui, LI Tong, JIA Li, YUAN Qi, LI Wenyu, GUO Wenbiao, LIANG Yang

2026, 45(7):  2358-2367.  doi:10.13292/j.1000-4890.202607.021

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Crossoptilon mantchuricum is a nationally first-class protected wild animal in China, the Provincial Bird of Shanxi Province, and a regional flagship species. Its survival and distribution are threatened by global climate change and habitat fragmentation. To assess spatiotemporal variations of suitable habitats, we employed an ensemble species distribution modeling framework (Biomod2), incorporating current climate data and two future climate scenarios (SSP126 and SSP585). Additionally, habitat quality (via InVEST) and ecological connectivity (using MSPA and Circuitscape) were evaluated to identify ecological sources, corridors, pinch points (bottlenecks with high resistance in dispersal pathways), and barrier points (structural obstacles that significantly disrupt ecological flows). Results showed that the species’ current suitable habitat is mainly concentrated in Lüliang and Taihang Mountains. Precipitation factors (bio_12, bio_13) and temperature stability (bio_03) were the most influential environmental variables. Under future climate change scenarios, the suitable habitat of Crossoptilon mantchuricum shows an overall contraction trend with a northward shift (SSP126: 129.6 km; SSP585: 131.2 km). The connectivity analysis identified 68 ecological corridors and 736 pinch points, mainly in the central and southern regions, indicating poor connectivity. Based on these findings, we propose three conservation strategies: (1) strengthening protection of core habitats to reduce anthropogenic disturbance; (2) optimizing the layout of ecological corridors to enhance landscape connectivity; and (3) integrating climate change and land-use factors into adaptive, long-term conservation planning. These results provide essential insights for protecting Crossoptilon mantchuricum and other alpine birds under climate change.





Whole-genome survey sequencing and microsatellite characterizations of Ophichthus urolophus.

ZHANG Yanyan, SHEN Fengzhen, YANG Tianyan

2026, 45(7):  2368-2377.  doi:10.13292/j.1000-4890.202607.006

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Ophichthus urolophus, a deep-sea benthic fish distributed in the waters around Taiwan, China, is one of the common species of family Ophichthidae. In this study, we used high-throughput sequencing technology to obtain the genomic survey data for O. urolophus, and screened microsatellite loci to analyze their composition and distribution. The results showed that the high-throughput sequencing yielded approximately 57.95 Gb of raw data, and subsequent quality filtering resulted in 332185654 high-quality reads. K-mer analysis estimated that the genome size of O. urolophus was about 2090 Mb, with the genomic heterozygosity rate being 0.75% and the proportion of repetitive sequences being 64.76%. In total, 1632962 microsatellite loci were identified, with a cumulative length of 2113854428 bp, randomly distributed across 1038185 sequences. The occurrence frequency, appearance frequency, and relative abundance of microsatellite loci were 13.91%, 21.88%, and 769.51 loci·Mb^-1, respectively. Among the six types of perfect microsatellites, dinucleotide repeats were the most prevalent, possessing the largest number (1024107, 27.52%), the highest appearance frequency (13.72%), and the greatest relative abundance (484 loci·Mb^-1). There were 2087 repeat motifs in total. Among which, hexanucleotide repeats had the highest variety of repeat motifs (1000) and mononucleotide repeats contained only 4 repeat motifs. Six dominant repeat motifs were successively A (139167, 40.93%), CA (334656, 32.68%), AAT (13067, 11.76%), CACG (7092, 5.81%), TGTAA (4510, 16.98%), and CACACG (440, 4.81%). In terms of the lengths of microsatellites, there were more medium and high-polymorphism microsatellites (Type I and Type II). In conclusion, there is a high complexity of the genome of O. urolophus and a high abundance of genomic microsatellite markers. Our results can provide data supports for the development of molecular markers and also offer references for further researches on the adaptive evolution of deep-sea fish species in the future.





Historical and seasonal variations and influencing factors of nitrogen and sulfur components in precipitation and PM_2.5 in Guiyang.

GAO Yunlong, WANG Xiaodan, MA Xi, ZHANG Jin, YUE Fujun

2026, 45(7):  2378-2388.  doi:10.13292/j.1000-4890.202607.036

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During urban development, a large number of nitrogen and sulfur compounds are emitted into the atmosphere, posing severe challenges to the urban ecological environment. Exploring the relationship between the transformation of energy structure and the sources and controlling factors of atmospheric nitrogen and sulfur pollutants during urban development holds great significance for the rational planning and allocation of energy. In this study, atmospheric rainfall water samples and PM_2.5 samples in 2023 and historical precipitation and industry and agriculture related statistical data from Guiyang were collected to assess NH₄⁺, NO₃^-, SO₄^2- concentration and their ratios. The long-term variations in nitrogen and sulfur deposition, as well as their relationship with changes in energy structure were analyzed. The results showed that the deposition of nitrogen and sulfur at the monthly scale was affected by precipitation, coal combustion and agricultural activities, exhibiting obvious seasonal variations. Affected by the changes of precipitation, temperature and source emissions, the equivalent concentrations of NO₃^-, NH₄⁺, SO₄^2- in spring and winter precipitation and PM_2.5 increased significantly, and the concentrations were relatively low in summer and autumn. Compared with other cities in China, Guiyang had higher SO₄^2- emissions. From 1994 to 2023, the proportion of nitrate in atmospheric nitrogen deposition had an increasing trend, which increased the supply of nitrogen in the ecosystems of the study area, and had a certain potential impact on water bodies, forests and other systems. The change of energy structure, production and life had an important impact on nitrogen, sulfur and other air pollutants. The emission type of air pollutants gradually changed from the sulfuric acid type in the early stage to a mixed type, mainly because the energy structure has gradually changed from coal based to oil and power based. Such change in emission types has significant guiding significance for the rational planning and allocation of energy as well as the optimized use of fertilizers.





Regulation of sulfur on the rhizosphere microenvironment of typical plants and the underlying mechanisms.

KANG Fengxin, HUANG Xuzheng, LI Zhiying, WEI Rongfei

2026, 45(7):  2389-2400.  doi:10.13292/j.1000-4890.202607.034

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The forms of sulfur significantly affect the rhizosphere environment of plants. However, the regulatory mechanism of sulfur on the rhizosphere microenvironment of hyperaccumulator plants remains unclear. Therefore, typical hyperaccumulator and tolerant plant species were cultivated in three types of soil with different levels of pollution under adding different sulfur forms (S₀ and SO₄^2-). We measured heavy metal concentrations in soils, organic acid concentrations in the roots, and microbial community structure. The regulatory effects of sulfur on organic acid concentrations and microbial community structure in roots were examined. The results showed that the application of sulfur (S₀) recruited genus Thiobacillus and decreased soil pH, while the application of sulfate (SO₄^2-) recruited genus Caldalkalibacillus, promoting the secretion of succinic acid. In lowly and moderately polluted soils, plants mainly secreted organic acids such as oxalic acid and malic acid, whereas in highly polluted soils, tartaric acid was primarily secreted. Microorganisms such as genus Streptomyces were significantly correlated with organic acid metabolism, which promoted heavy metal absorption by plants. This study provides theoretical and practical guideline for the remediation of heavy metal-contaminated soils.





Analysis of spatial heterogeneity of the coupling coordination between urbanization and ecological environment using time-series remote sensing: A case study of the coastal urban belt in the Yangtze River Delta.

SHEN Xingru, SUN Chao, ZHAO Saishuai, ZHAO Chenwei

2026, 45(7):  2401-2413.  doi:10.13292/j.1000-4890.202607.029

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With the continuous development of society, coordinating urbanization with the ecological environment has become a critical challenge for sustainable regional development. This study aims to advance the understanding of spatial heterogeneity in the coupling coordination between urbanization and ecological environment using time-series remote sensing technology, a departure from traditional statistical data analysis. Specifically, we developed a composite nighttime light index (CNLI) to spatially represent urbanization levels and a time-series remote sensing ecological index (ts-RSEI) to assess ecological conditions. By combining quadrant analysis with the coupling coordination degree (CCD) model, we examined the urbanizationecological environment relationship in the coastal urban belt of the Yangtze River Delta during 1992-2021. The results showed that: (1) Shanghai consistently exhibited the highest level of urbanization, driving the urbanization development in neighboring cities, especially in the southern delta. (2) Ecological degradation displayed a bimodal distribution, with significant declines in cities between Shanghai and Zhoushan. (3) Overall, the coupling coordination between urbanization and the ecological environment shifted from the second quadrant to the fourth quadrant. The CCD followed an “inverted U-shaped” trend, increasing from 0.356 to 0.684 and then decreasing to 0.432. Spatially, the coupling coordination between urbanization and the ecological environment in Shanghai and its surrounding cities (e.g., Nantong, Jiaxing, Ningbo, Zhoushan, and Taizhou) shifted from the regional peak in the 1990s to the regional trough in the 2020s, and the downward trend gradually slowed down after 2015. In contrast, cities in the northern and southern delta (e.g., Lianyungang, Yancheng, and Wenzhou) as well as their suburban areas gained an advantage in the coupling coordination between urbanization and ecological environment. This pattern of spatially heterogeneous development is closely linked to the allocation of natural resources and policy-driven urban infrastructure optimization.





Spatiotemporal variations of carbon fluxes in urban forests and the spatial coupling relationship with carbon emissions.

LIU Lin, ZHAO Yanzhi, XIAO Xiao, REN Wanxia, LI Ke, GANG Shuang

2026, 45(7):  2414-2425.  doi:10.13292/j.1000-4890.202607.026

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Urban forests serve as a crucial ecological barrier to address climate change and carbon goals by optimizing human settlement quality, enhancing carbon sequestration, and improving urban climate. However, carbon fluxes within urban forests are largely unexplored. In this study, we used eddy covariance technology and a flux footprint model to analyze the spatial-temporal variations and key drivers of carbon fluxes in Beiling Park of Shenyang City from 2023 to 2024. The results showed that annual carbon fluxes ranged from -17 to 13 μmol·m^-2·s^-1, with daily averages fluctuating between -6.32 and 2.1 μmol·m^-2·s^-1. The forest in the park functioned as a carbon sink for only 44 days in each year. The carbon sink capacity varied seasonally, with the strongest carbon sink in summer and a carbon source in winter. Temperature was the dominant factor influencing carbon flux. We used an extended STIRPAT model to project carbon emissions under baseline scenario and multi-source data to estimate carbon emissions of urban functional zones. An analysis of the spatial correlation between carbon flux and carbon emissions revealed that high carbon emission areas concentrated in industrial and commercial zones, which was highly overlapped with carbon flux hotspots. This study provides a valuable dataset and methodological reference for monitoring carbon fluxes in urban forests, underscoring the importance of optimizing urban planning to enhance carbon sinks. Future research should integrate multi-source remote sensing and model simulations to elucidate the underlying mechanisms.





Research progress and prospects for assessment models of terrestrial ecosystem services.

YU Meini, XU Gexi, CHEN Jian, LIU Shun, JIA Lei, FENG Zhe, SUN Zhen, SHI Zuomin

2026, 45(7):  2426-2438.  doi:10.13292/j.1000-4890.202607.022

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In recent years, global climate change and human activities have accelerated the changes in terrestrial ecosystem structure and functions. Consequently, ecosystem service assessment has gradually become a research focus in the fields of ecology and resource and environmental management. Advancements in integrated space-air-ground monitoring systems and the development of multisource data fusion technologies have led to an evolution for the methods used to assess ecosystem services. These methods are transitioning from conventional empirical estimation towards process-based simulation, multi-model integration, and comprehensive evaluation. However, most previous studies have largely focused on individual models, lacking systematic comparison and in-depth investigation of the construction principles, applicable conditions, and uncertainties associated with different types of assessment models. We systematically review the development and evolution of terrestrial ecosystem service assessment models. These models are categorized into four types according to their underlying mechanisms: process-based models, remote sensing-based models, empirical models, and interdisciplinary integrated models. The applications, advantages, and limitations of these models are comparatively analyzed in the assessment of key ecosystem services, including carbon storage, water conservation, soil retention, and biodiversity. A comprehensive analysis indicates that ecosystem service assessment models have been widely applied and have reached a relatively mature stage, but they still face three major challenges. (1) Data sources primarily rely on existing datasets derived from non-in-situ observations and proxy indicators for ecosystem services, which diminishes the credibility of assessment outcomes. (2) Models excessively depend on simplified assumptions and empirical parameters with insufficient validation and uncertainty analysis. (3) Spatial scales fail to align with ecological processes, which compromises the interpretability and applicability of model results. In response to these challenges and current development trends, we put forward suggestions for future improvements from the following three perspectives: model parameter localization, the integration of multi-source data and artificial intelligence, and multi-model coupling. The findings provide a basis for selecting, optimizing and integrating terrestrial ecosystem service assessment models, aiming to provide better supports for land use spatial planning and resource management.





Research advances in the effects of grazing management on the functional stability of grasslands.

WANG He, ZHU Juntao, HE Yunlong, WANG Xiuwei, GU Huiyan, LI Sifan

2026, 45(7):  2439-2446.  doi:10.13292/j.1000-4890.202607.016

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As one of the most extensively distributed ecosystems worldwide, grasslands provide indispensable ecosystem services for human wellbeing. However, intensifying irrational anthropogenic disturbances such as overgrazing has posed severe threats to functional stability of grasslands. To date, the systematic understanding of the regulatory mechanisms governing grassland functional stability under grazing management remains scarce. Based on the multidimensional framework of ecosystem functional stability and the diversity-stability theory, we systematically reviewed literature and analyzed the impacts of grazing regimes (e.g., rotational, seasonal grazing), intensities (e.g., moderate, heavy grazing), and durations (e.g., short-term, long-term) on multidimensional stability, as well as the underlying mechanisms. The results showed that, except for continuous heavy grazing that negatively affected the functional stability of desert steppe, moderate grazing in most cases can maintain or even enhance the functional stability of grasslands. Moderate grazing primarily regulated the temporal stability of plant productivity by altering species diversity and species compensation, with its effects further mediated by environmental factors such as soil nutrient availability. In addition, we identified knowledge gaps in quantitative assessments and mechanistic understanding of resistance, recovery, and resilience of grasslands under grazing. This review would provide a theoretical basis for elucidating the maintenance mechanisms of grassland ecosystem stability under grazing and for optimizing grassland management, thereby facilitating the coordinated development of sustainable utilization of grassland resources and ecological conservation.





Evolution characteristics of compound heat and drought events for single-season rice in Southwest China based on Copula function.

LEI Zhiwen, CHEN Dongdong, LI Xiaowei, ZHANG Yi

2026, 45(7):  2447-2457.  doi:10.13292/j.1000-4890.202607.003

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Based on daily meteorological data from 351 stations in single-season rice planting areas of Southwest China and the data of critical phenological stages of single-season rice during 1980-2022, we examined the spatiotemporal variations of compound events of heat and drought events during critical phenological stages of single-season rice in subregions (by dividing the region according to the phenological stages). The Copula function was employed to construct two-dimensional joint cumulative probability distributions of high-temperature intensity and drought intensity for each subregion, and the recurrence intervals and occurrence patterns of compound events were analyzed. The results showed that the frequency of compound events during both the heading-filling and filling-maturity stages followed a pattern of “lower in west, higher in east” and “lower in south, higher in north”. High-frequency areas during the heading-filling stage were concentrated in Chongqing, northern and eastern Guizhou, and parts of Panxi in Sichuan, while those during the filling-maturity stage slightly shifted southward and become less extensive. From 1980 to 2022, the frequency of compound events during both stages increased, with a more significant increase in moderate-to-severe events during heading-filling stage starting from 1990 and a larger increase in severe compound events during filling-maturity stage. Student’s t Copula function optimally fitted the joint distribution of heat intensity and drought intensity in most subregions, followed by Frank and Gumbel Copula functions. The recurrence intervals of compound events increased with intensified heat and drought intensities, with drought intensity exerting a stronger influence. Compound events occurred more frequently during the heading-filling stage, while higher-intensity events predominated during the filling-maturity stage. This study clarified the evolutionary characteristics of compound heat and drought events during the critical phenological stages of single-season rice, providing a scientific basis for disaster prevention and mitigation in rice production.





eDNA-based monitoring and early warning of invasive fish in typical urban lakes of Guangdong.

SHU Lu, YU Fandong, FANG Miao, XU Meng, WEI Hui, WANG Xuejie, GU Dangen

2026, 45(7):  2458-2464. 

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To explore the potential application of environmental DNA (eDNA) technology in the early warning of invasive fish species in urban lakes, we investigated three representative lakes in the Pearl River Delta region, Xing Lake in Zhaoqing, Shunfengshan Lake in Foshan, and Dongshan Lake in Guangzhou. All of them are heavily impacted by invasive fish. Water samples were collected from Xing Lake and Shunfengshan Lake in March 2023 and from Dongshan Lake in November 2024. Using eDNA metabarcoding, we monitored the status of invasive fish, provided early-warning assessments, and evaluated the effectiveness of eDNA detection. A total of 59 fish taxa were detected, including 13 invasive species, with 7, 8, and 10 species being identified in Xing, Shunfengshan, and Dongshan lakes, respectively. The relative abundance of invasive fish reached 44.45%, 47.19%, and 35.58% in the three lakes. Coptodon zillii, Oreochromis niloticus, and Pterygoplichthys pardalis exhibited high overall relative abundances (14.01%, 14.05%, and 6.64%) and were dominant species at certain sampling sites. In Xing Lake, the relative sequence abundance of invasive fish obtained via eDNA showed a significant positive correlation with both the relative abundance and relative biomass derived from traditional methods (R=0.89 and 0.91 respectively, P< 0.01), demonstrating a high reliability of eDNA for quantitative detection of invasive fish distributions. This study provides a scientific basis for the prevention and ecological management of invasive fish in urban lakes and confirms the efficiency and potential of eDNA technology in invasive fish species monitoring.