Search Results (583)

As critical ecosystems, coastal zones necessitate the identification of their ecosystem service values, trade-off/synergy patterns, spatiotemporal evolution, and driving factors to inform scientific decision-making for sustainable ecosystem management. This study selected the coastal zone of the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) as the research region. By incorporating land-use types such as mangroves, tidal flats, and aquaculture areas, we analyzed land-use changes in 1990, 2000, 2010, and 2020. The InVEST model was employed to quantify six key ecosystem services (ESs): annual water yield, urban stormwater retention, urban flood risk mitigation, soil conservation, coastal blue carbon storage, and habitat quality, while spatial correlations among them were examined. Furthermore, Spearman’s rank correlation coefficient was used to assess trade-offs and synergies between ecosystem services, and redundancy analysis (RDA) combined with the geographically and temporally weighted regression (GTWR) model were applied to identify driving factors and their spatial heterogeneity. The results indicate that: (1) Cultivated land, forest land, impervious surfaces, and water bodies exhibited the most significant changes over the 30-year period; (2) Synergies predominated among most ecosystem services, whereas habitat quality showed trade-offs with others; (3) Among natural drivers, the normalized difference vegetation index (NDVI, positive effect) and evapotranspiration were critical factors. The proportion of impervious surfaces served as a key land-use change driver, and the nighttime light index emerged as a primary socioeconomic factor (negative effect). The impacts of drivers on ecosystem services displayed notable spatial heterogeneity. These findings provide scientific support for managing the supply-demand balance of coastal ecosystem services, rational land development, and sustainable development. Full article

The hydrological processes of red soil slope farmland are complex, and the vertical migration of nitrogen (N) is influenced by these processes, which present different layering characteristics of water flow. Previous studies on the vertically stratified transport of N on slope soils have mainly relied on rainfall simulation, lacking a comprehensive study of the overall process of N leaching from surface soil to underground under natural conditions. To investigate the impact of these hydrological processes on the transport of N at different layers under natural rainfall events, large-scale field runoff plots were constructed as draining lysimeters to conduct a consecutive 2-year observation experiment at Jiangxi Soil and Water Conservation Ecological Science and Technology Experimental Station, China. The runoff (the water of 0 cm), interflow, deep percolation, soil moisture content (SMC), total nitrogen (TN), nitrate nitrogen (NO₃⁻-N) and ammonium nitrogen (NH₄⁺-N) concentrations were monitored and determined. The N loss of red soil farmland under two treatments, namely grass mulching (FC, a coverage of 100% with Bahia grass) and exposed treatment (BL, without anything covered), were measured. The relationships between hydrological factors and different forms of N losses were analyzed. The results indicate the following: (1) Deep percolation is the main pathway of water loss and N loss for red soil slope farmland, accounting for over 85% of the total water loss and N Loss. Grass mulching can significantly reduce surface runoff and N loss. (2) Vertically stratified N is mainly NO₃⁻-N, and the concentrations of each form of N show the same trend: deep percolation > interflow > runoff. (3) Water loss, rainfall, and SMC are closely related to the stratified loss of N, with correlation coefficients ranging from 0.74 to 0.98. The correlation analysis and redundancy analysis (RDA) on the relationships between different forms of N losses and hydrological factors indicate that rainfall was the primary factor driving the stratified loss of N in red soil slope farmland. Full article

To investigate the effects of long-term elevated atmospheric CO₂ (eCO₂) on the distribution and stability of soil aggregates and microbial characteristics in wetland soils and to reveal the mechanisms by which eCO₂ influences soil organic carbon (SOC) sequestration, a multi-temporal-scale eCO₂ control experiment was conducted in the Sanjiang Plain wetland with treatments at ambient CO₂ concentration (AC), 550 ppm, and 700 ppm CO₂. Soil aggregate fractionation, phospholipid fatty acid (PLFA) analysis, and redundancy analysis (RDA) were used to analyze changes in aggregate size distribution, stability indices (MWD, GMD), microbial biomass, and community structure. The results showed that eCO₂ significantly affected aggregate size distribution. Both short- and long-term exposure to low-concentration eCO₂ reduced the proportion of large aggregates. Over time, the proportion of silt and clay particles increased, while microaggregates decreased. Although CO₂ concentration did not directly affect MWD and GMD, long-term eCO₂ significantly reduced soil aggregate stability. Microbial biomass and diversity were not sensitive to CO₂ concentration but decreased significantly with prolonged exposure. In contrast, microbial community structure was significantly affected by both CO₂ level and exposure duration. RDA indicated that, under short-term eCO₂, aggregate fractions were positively correlated with microbial biomass, whereas, under medium- and long-term treatments, they were positively correlated with soil physicochemical properties. Macroaggregates were positively correlated with aggregate stability, while microaggregates and silt–clay fractions were negatively correlated—a relationship that strengthened with longer eCO₂ exposure. Thus, long-term eCO₂ altered soil aggregate structure and microbial communities, ultimately influencing SOC stability. These findings provide data and theoretical support for predicting soil carbon stability and ecosystem functioning in wetlands under climate change. Full article

The mechanisms by which iron ore mining activities affect the surrounding rhizobacterial ecology remain unclear. This study employed 16S rRNA high-throughput sequencing to analyze the structure and function of rhizosphere bacterial communities associated with three local crops, Musa basjoo Siebold L., Triticum aestivum L., and Amygdalus persica L., in mining areas. It is noteworthy that in the iron mining area, the relative abundance of Sphingomonas and Nitrososphaeraceae in the soil has decreased. In contrast, the relative abundance of Streptomyces in the rhizosphere soil has increased due to mining activities. Pearson correlation analysis showed that the abundance of Sphingomonas is significantly positively correlated with the soil organic carbon content. Redundancy analysis (RDA) indicates that Streptomyces exhibits a significant positive correlation with soil titanium and pH content, while showing a negative correlation with iron and lead content. Full article

The dynamic response of soil bacterial communities to fertilization throughout the entire crop growth cycle remains inadequately characterized. To address this, we conducted a long-term field experiment in Jiangle County, Fujian Province, China, and collected soil samples across four rice growth stages (tillering, elongation, filling and maturity) under five fertilization regimes: no fertilization (CK); chemical fertilizer (NPK); and NPK supplemented with extra nitrogen (NPKN), extra phosphorus (NPKP) and rice straw (NPKS). Bacterial communities were analyzed by high-throughput sequencing. Our results revealed that soil bacterial diversity decreased progressively throughout the growth stages, with fertilization exerting only a minor influence. Structural equation modeling (SEM) identified daily mean temperature (DMT) as the factor with the strongest direct and total effects on the diversity. In contrast, fertilization regimes were the primary determinant of the community structure. Mantel test and redundancy analysis (RDA) indicated that soil pH was the most important factor shaping the community structure. Soil bacterial network attributes also varied mainly with fertilization: fertilizer addition reduced the complexity but enhanced stability, with NPK and NPKS showing the greatest stability. Regarding rice yields, all fertilized treatments were comparable but considerably higher than CK. In conclusion, rice growth stages primarily influenced soil bacterial diversity, while fertilization regimes predominantly shaped the community structure and network attributes. Further, we recommend NPK and NPKS as optimal strategies for balancing crop production, agroecosystem sustainability and environmental health. Full article

To investigate the response of soil microbial communities to reduce chemical fertilization supplementation with organic fertilizer in Acanthopanax senticosus cultivation, we analyzed the diversity, composition, and structure of soil microbiota by using high-throughput sequencing technology. The results showed that reducing chemical fertilizer application significantly increased soil microbial richness (ACE and Chao1 indices), which was positively correlated with soil total nitrogen (TN) content. At the phylum level, the relative abundance of Cyanobacteria decreased at T2 (reduction of 20% for fertilizer application) but increased at T4 (reduction of 60% for fertilization application), exhibiting an opposite trend to Bacteroidetes. At the genus level, the relative abundance of Paucibacter was significantly higher in T4 than in other treatments, while Nitrospira reached its peak under T3 treatment. For fungal communities, the richness index showed a non-linear response, initially decreasing and then increasing, which was positively correlated with the soil available potassium (AK) content. At the phylum level, reduced fertilizer application significantly reduced the relative abundance of Ascomycota compared to conventional fertilization. At the genus level, the relative abundance of Fusarium was significantly lower in the T4 treatment than in the other treatments. Redundancy analysis (RDA) revealed that the total organic carbon (TOC), TN, and AK were the key environmental factors affecting the soil microbial community. This study demonstrated that partial substitution of chemical fertilizers with organic amendments can improve soil physicochemical properties and enhance microbial diversity, providing a scientific basis for developing sustainable fertilization strategies for Acanthopanax senticosus cultivation. Full article

The ecological strategies of understory shrubs are critical for maintaining the structure and function of forest understory vegetation. Understanding the assembly mechanisms of these shrub communities is a central issue in modern ecology. To address this, our study was conducted in the typical red soil regions of Jiangxi, China, focusing on secondary forests (including both broadleaved and coniferous types) of similar stand age. We aimed to assess the effects of various environmental factors—such as soil pH, total nitrogen content, bulk density, and understory temperature—along with tree-layer characteristics—including canopy closure, tree species richness, and diameter at breast height (DBH)—on the species composition, functional traits, and phylogenetic structure of the shrub layer. Results showed: One-way ANOVA revealed significant differences in functional traits between the two forest types. Specifically, leaf thickness, specific leaf area, and chlorophyll content were significantly higher in the coniferous forest, whereas leaf dry matter content was significantly lower compared to the broadleaved forest (p < 0.05). These results suggest that understory shrubs in the coniferous forest primarily adopt a resource-conservative strategy, while those in the broadleaved forest exhibit a resource-acquisitive strategy. Phylogenetic analysis further revealed that the phylogenetic diversity (PD) of coniferous forests was significantly lower than that of broadleaved forests (p < 0.05). The phylogenetic structure in coniferous forests showed a more clustered pattern (NTI > 0, NRI > 0), suggesting stronger environmental filtering. Diversity index analysis showed that the Chao1 index indicated a richer potential species pool in broadleaved forests (p < 0.05), while species distribution was more even in coniferous forests (p < 0.05). Random Forest model analysis identified the diameter at breast height (DBH) of trees as the most critical negative driver, while soil pH was the primary positive driver. Redundancy Analysis (RDA) confirmed that the community structure in coniferous forests was mainly driven by biotic competition pressure represented by DBH, whereas the structure in broadleaved forests was more closely associated with abiotic factors like soil total nitrogen and pH (R² = 0.29, p < 0.05). These environmental drivers, through strong environmental filtering, collectively resulted in a phylogenetically clustered pattern of shrub communities in both forest types. This study demonstrates that the assembly of understory shrub communities is a complex, multi-level process co-regulated by multiple factors, shaped by both the biotic pressure from the overstory structure and abiotic filtering from the soil environment. This finding deepens our understanding of the rules governing community assembly in forest ecosystems. Full article

The objectives of this study were to investigate the zooplankton community in the important estuarine areas of Qinhuangdao Sea in the Bohai Sea, analyze the variation characteristics of the zooplankton community, and explore the construction and evolutionary mechanisms of its community structure and function. We conducted zooplankton monitoring in the four seasons of 2024 at Daihe Estuary (DHK), Yanghe Estuary (YHK), Shihe Estuary (SHK), Tanghe Estuary (THK), and Luanhe Estuary (LHK). The results showed that the diversity index and richness index in summer were significantly higher than those in winter (p < 0.05). Based on the body size, feeding habits, reproduction types, life cycles, and escape abilities of zooplankton, the zooplankton in the ecosystem were divided into 17 zooplankton functional groups. The zooplankton examined in this study were divided into 11 functional groups. Except for THK, the dominant functional groups in other estuaries in all seasons were SCF (Small copepods and claocera filter feeders) and LCF (Large copepods and claocera filter feeders); PP (Protozoan photosynthetic autotrophs) and PB (Protozoan bacterivores) functional groups dominated THK. Pearson correlation analysis and RDA multivariate statistical analysis revealed that interspecific competition, PO₄³⁻-P, NO₂⁻-N, and SAL were the primary driving factors influencing community construction. The spatial-temporal variations in T, PO₄³⁻-P, NO₂⁻-N, and SAL in the five estuaries were evident, and the pH and DO in the water environment exhibited a high degree of overlap in seasonal changes. The density of zooplankton functional groups was significantly positively correlated with PO₄³⁻-P, NO₃⁻-N, NO₂⁻-N, NH₄⁺-N and SAL (p < 0.05). Furthermore, the SCF and LCF functional groups played a dominant role. According to the analysis of niche overlap and AC interspecific association, it was shown that zooplankton populations in small-scale areas mostly exhibited negative correlations dominated by competition and predation. In contrast, the functional groups of zooplankton in large-scale areas mostly demonstrated mutually synergistic facilitative relationships. The results of this study showed that interspecific relationships are more important for the community structure of zooplankton. This study contributes to understanding the responses of primary producers and primary consumers to water environmental changes in estuarine ecosystems, laying a foundation for further analyzing the mechanisms of zooplankton community construction and survival strategy selection in special estuarine habitats. It also provides references for the scientific management of estuarine areas and the avoidance of pollution risks. Full article

Seagrass beds are among the most productive and ecologically valuable coastal ecosystems. However, temperate nearshore seagrass beds exposed to urban stressors remain understudied. From 2020 to 2024, this study investigated seagrass communities, environmental factors, and benthic macrofauna in Qingdao’s coastal bays (Qingdao Bay, Huiquan Bay and Tangdao Bay) using field sampling and remote sensing. Redundancy analysis (RDA), Spearman correlation, and PERMANOVA were applied to clarify the ecological response relationships among these components. Results revealed significant spatiotemporal variations: Qingdao Bay experienced severe degradation with an 88% decline in belowground biomass. Huiquan Bay showed shoot height increases but ecological instability, while Tangdao Bay maintained relatively stable conditions. Mollusks dominated Qingdao Bay (67.4%), whereas annelids were prevalent in Huiquan Bay (51.8%) and Tangdao Bay (69.6%). Tangdao Bay supported the most complex and stable benthic communities. Water depth acted as a stressor to seagrass growth, while the role of dissolved oxygen and salinity was complex, exhibiting context-dependent relationships with seagrass parameters. Dissolved inorganic nitrogen and reactive phosphate were shared positive drivers for both seagrasses and macrofauna. This study conclusively links specific environmental drivers to seagrass ecosystem dynamics, delivering essential insights for effective ecological management and restoration strategies. Full article

The Daurian ground squirrel (Spermophilus dauricus) is an important animal model that is frequently used by researchers studying the physiological ecology of hibernation in China. There has been considerable controversy regarding the classification of its subspecies, and there is a lack of relevant comparisons of morphometric data. To clarify this issue, this study aims to systematically compare five external morphological traits and 20 cranial traits of S. dauricus collected from 10 locations within China to assess the phenotypic differentiation of S. dauricus within China. Through morphological cluster analysis (MCA), discriminant function analysis (DFA), and principal component analysis (PCA), the samples from 10 locations (FK, n = 5; JZ, n = 11; DQ, n = 7; KP, n = 6; HEB, n = 4; EE, n = 10; CF, n = 3; ZB, n = 6; CD, n = 8; WL, n = 7) can be divided into three geographical populations: the Northeast population (NE); the Inner Mongolia population (IM); and the Hebei population (HB). There is significant morphological variation in four external traits and 19 cranial traits among populations within the species. Specifically, the NE population presented greater body length, tail length, and cranial dimensions. The IM population has the shortest tail, whereas the HB population has the smallest overall body size—its tail length, however, falls between those of the NE and IM populations. These morphological differences may be related to differences in habitat. This study revealed a significant correlation between environmental factors and the morphological traits of S. dauricus. Redundancy analysis (RDA) further revealed that the mean annual temperature (MAT) and mean annual precipitation (MAP) significantly affected the morphological traits of S. dauricus. This study challenges the current subspecies classification, clarifies the geographical morphological variation pattern of S. dauricus, reveals the influence of the environment on the differentiation of its morphological traits, and provides new morphological evidence for resolving the controversy over its subspecies classification. Full article

Ice krill (Euphausia crystallorophias) play a key role in the Antarctic coastal ecosystem, yet its spatial growth variability remains poorly understood. This study examined 5298 krill individuals from 52 stations across the Amundsen Sea, transitional waters, and the Ross Sea, collected between 2020 and 2024. Length–weight relationships (LWR) were constructed to derive the condition factor a and the allometric growth exponent b, followed by regional comparisons and environmental response analyses using boxplots, redundancy analysis (RDA), and generalized additive models (GAM). Boxplots revealed that a was significantly higher in the Amundsen Sea and transitional zone than in the Ross Sea, while b was highest and most variable in the Amundsen Sea. RDA indicated that a was primarily associated with depth, latitude, mean temperature, and mean salinity, whereas b was influenced by sea surface temperature, chlorophyll-a, sea ice concentration, and longitude. GAM further showed nonlinear responses of a to mean temperature, mean salinity, and depth, with peaks near −0.5 °C, 34.2 PSU, and 3500 m, respectively. These results suggest that krill in deep, cold, and less-productive transitional zone allocate more energy to body condition (high value a), while those in warmer, moderately productive regions like the Amundsen Sea invest more in structural growth (high value b). This study provides new insights into the environmentally driven growth strategies of ice krill and contributes to understanding its ecological adaptability under changing climatic and oceanographic conditions. Full article

The inconsistent efficacy of biochar in mitigating agricultural greenhouse gas emissions remains a major barrier to its widespread adoption and the realization of its environmental benefits. This study aimed to develop a stable and efficient mitigation strategy by optimizing biochar physicochemical properties through urea-N activation (corn stover: urea mass ratios of 5:1 and 15:1). Five treatments were established: CK (control), GC (fertilization), GB (fertilization + raw biochar), GAB5 (fertilization + low-N activated biochar), and GAB15 (fertilization + high-N activated biochar). Mechanisms were elucidated by monitoring soil profile (0–20 cm) gas concentrations and surface fluxes, combined with a comprehensive analysis of soil physicochemical properties, enzyme activities, and microbial biomass. Results demonstrated that activated biochar, particularly GAB15, significantly reduced cumulative CO₂ (9.4%, p < 0.05) and N₂O (45.2%, p < 0.05) emissions and their concentrations in the 0–10 cm layer. This superior efficacy was linked to profound improvements in key soil properties: GAB15 significantly enhanced soil cation exchange capacity (CEC, increased by 17.3%, p < 0.05), NH₄⁺-N content (increased by 88.2%, p < 0.05), Mean Weight Diameter (MWD, increased by 13.0%), the content of water-stable aggregates > 0.25 mm (R_>0.25mm, increased by 57.3%) (p < 0.05), dissolved organic carbon (DOC), and the MBC (microbial biomass carbon)/MBN (soil microbial biomass nitrogen) ratio. Redundancy analysis (RDA) and structural equation modeling (SEM) revealed core mechanisms: CO₂ mitigation primarily stemmed from the physical protection of organic carbon within macroaggregates and a negative priming effect induced by an elevated MBC/MBN ratio; N₂O mitigation was attributed to weakened nitrogen mineralization due to enhanced aggregate stability and reduced substrate (inorganic N) availability for nitrification/denitrification via strong adsorption at the biochar–soil interface. This study confirms that urea-activated biochar produced at a 15:1 corn stover-to-urea mass ratio (GAB15) effectively overcomes the inconsistent efficacy of conventional biochar by targeted physicochemical optimization, offering a promising and technically feasible approach for mitigating agricultural greenhouse gas emissions. Full article

Polyaspartic acid (PASP), a biodegradable and eco-friendly fertilizer synergist that shows potential to enhance nutrient use efficiency in agricultural systems, has its integrative role with rhizosphere microorganisms remain insufficiently explored. This study integrated outdoor pot experiments, soil biochemical analysis, and microbiome sequencing to investigate the effects of co-application of PASP and the plant growth-promoting rhizobacterium (PGPR) Enterobacter asburiae S13 on potato growth, with four treatments set up including blank control (CK), sole application of PASP (S0P1), sole inoculation of PGPR (S1P0), and co-application of PASP and PGPR (S1P1), and 25 pots per treatment as replicates. The results showed that, compared with the S0P1 treatment, the S1P1 treatment significantly increased plant height (9.59%), stem diameter (28.39%), root length (38.61%), as well as root and shoot biomass (21.26% and 25.17%, respectively) (ANOVA, Duncan’s test, p < 0.05). It also enhanced ammonium nitrogen (40.00%), nitrate nitrogen (57.70%), available potassium (47.56%), and urease activity in the rhizosphere soil (ANOVA, Duncan’s test, p < 0.05). 16S rRNA sequencing revealed that the S1P1 treatment enriched beneficial taxa such as Paucibacter and Massilia, while suppressing competitive genera such as Duganella and Pedobacter. Redundancy analysis (RDA) indicated that available potassium and ammonium nitrogen were the key factors shaping the microbial community structure. In conclusion, combining PASP with PGPR synergistically improves soil nutrient availability and reshapes the rhizosphere microbiome, resulting in enhanced potato growth, thus demonstrating its potential as a dual-function biostimulant for eco-efficient and sustainable potato production systems. Full article

The sustainable development of resource-based cities faces challenges due to the imbalance between ecosystem service supply and demand. This study examines Xingtai, a typical resource-based city located in northern China, using ecosystem service bundle theory to analyze the supply–demand relationships of six ecosystem services—water yield, soil retention, habitat quality, urban cooling, PM_2.5 removal, and carbon sequestration—from 2000 to 2020. Based on the ratio of supply–demand, we identify ecosystem service bundles and explore their driving factors using redundancy analysis (RDA) and the geographically and temporally weighted regression (GTWR) model. Results show a clear “mountain–plain” supply gradient, with high supply in the western Taihang Mountains and low supply in urbanized eastern plains. Demand follows a “center-high, periphery-low” pattern, with urban centers showing higher demand for urban cooling and PM_2.5 removal. A severe supply–demand imbalance exists: soil retention, PM_2.5 removal, habitat quality, and carbon sequestration are undersupplied in urbanized areas, while water yield and urban cooling are oversupplied in the western mountains. Natural factors (precipitation and temperature) shape western mountain supply, while human activities (GDP and nighttime light) drive demand polarization in the east. GTWR results reveal that urban GDP growth and land expansion intensify demand, while stable supply in mountain areas relies on precipitation and forest cover. This study provides scientific support for the sustainable development of resource-based cities. Full article

This study investigates the distribution patterns, interspecific relationships, and community stability mechanisms of phytoplankton functional groups, aiming to elucidate the ecological processes that drive phytoplankton communities in aquatic ecosystems of arid regions. We conducted seasonal sampling from 2023 to 2024 at four auxiliary reservoirs in the Tarim River Basin, namely Shangyou Reservoir (SY), Shengli Reservoir (SL), Duolang Reservoir (DL), and Xinjingzi Reservoir (XJZ). In recent years, researchers have grouped phytoplankton into functional groups based on their shared morphological, physiological, and ecological characteristics—with these three types of traits serving as the core criteria for distinguishing different functional groups. A total of 18 functional groups were identified from the phytoplankton collected across four seasons, among which eight (A, D, H1, L0, M, MP, P, and S1) are dominant. Redundancy Analysis (RDA) indicated that environmental factors such as pH, electrical conductivity (COND), and dissolved oxygen (DO) are key driving factors affecting phytoplankton functional groups. Interspecific association analysis showed that the phytoplankton communities in DL, SL, and XJZ reservoirs were dominated by positive associations, reflecting stable community structures that are less prone to drastic fluctuations under stable environmental conditions. In contrast, the SY Reservoir was dominated by negative associations, indicating that it is in the early stage of succession with an unstable community. This may be related to intense human disturbance to the reservoir and its role in replenishing the Tarim River, which leads to significant water level fluctuations. The results of the Chi-square test and Pearson correlation analysis showed consistent trends but also differences: constrained by the requirement for continuous normal distribution, Pearson correlation analysis identified more pairs of negative associations, reflecting its limitations in analysing clumped-distributed species. Random forest models further indicated that functional groups M, MP, L0, and S1 are the main positive drivers of interspecific relationships. Among them, the increase in S1 can promote the growth of functional groups dominated by Navicula sp. and Chroococcus sp. by reducing resource competition. Conversely, the expansion of functional group H1 inhibits other groups, which is related to its adaptive strategy of resisting photo-oxidation in eutrophic environments. This study reveals the patterns of interspecific interactions and stability mechanisms of phytoplankton functional groups in arid-region reservoirs, providing a scientific basis for the management and conservation of aquatic ecosystems in similar extreme environments. Full article