To clarify the impacts of urban development on soil microbes in parks, we compared abundance and composition of soil microbial communities along an urbanization gradient in Shanghai using real-time PCR and Illumina high-throughput sequencing. Moreover, the effects of soil chemical characteristics on microbial communities were analyzed. The results showed that the abundance and alpha diversity of bacterial and fungal communities in parks in urbanized areas were comparable to or higher than those in rural areas. Compared with the parks in rural areas, relative abundances of the phyla Nitrospirae and Verrucomicrobia in parks in the central urban areas significantly increased, while Gemmatimonadetes decreased. Relative abundance of the class Eurotiomycetes in parks in the central and developed urban areas was significantly higher than those in the rural areas. Soil chemical properties and heavy metal pollutants had significant impacts on the abundance and composition of microbial communities, but their relative importance was quite different. Soil available zinc was the most important factor shaping the composition of both bacteria and fungi in park soils. In addition, soil pH, available copper, and available magnesium were the primary drivers of soil bacterial community, while total mercury, total zinc, and available lead were more important in shaping soil fungal community composition.

Leaf functional traits, which reflect life history strategy of plant species, influence regeneration success and individual numbers. To explore the mechanisms of understory regeneration during vegetation restoration from the perspective of leaf functional traits, we investigated the canopy and regeneration layers of a near-natural forest on the Ecological Island at East China Normal University’s Minhang Campus. Nine leaf functional traits of dominant species in both layers were measured. Regression analysis and principal component analysis were employed to assess the interspecific differences in the number of regenerating individuals under the forest and their associations with leaf functional traits. The canopy comprised both evergreen and deciduous trees, while evergreen species were more prevalent in the regeneration layer. Species in both layers had higher leaf carbon/nitrogen and carbon/phosphorus ratios, and lower specific leaf area, nitrogen, and phosphorus contents than those presented in the canopy only. The density and dominance of species in the regeneration layer were negatively correlated with specific leaf area and leaf phosphorus content but positively correlated with leaf carbon/phosphorus ratio. The principal component analysis of leaf traits reflected a leaf economics spectrum along the first axis, with species scores on this axis negatively correlated with density and dominance in regeneration layer. This suggests that species favoring a slow investment-return strategy tend to have higher density and dominance. In summary, leaf economics traits reliably predict understory regeneration in urban near-natural forests, providing guidance for species selection in near-natural restoration of urban forests.

Net primary productivity (NPP) of vegetation is a key component in the carbon cycle and energy flow of ecosystems, influenced by both natural and human factors. As one of key development regions in China, the Jing-Jin-Ji Region (Beijing-Tianjin-Hebei, BTH) should focus on both economic growth and ecological construction. Unveiling the trends of NPP changes and their influencing factors is of great significance for formulating urban sustainable development policies. In this study, we investigated the trends and influencing factors of NPP in the BTH region from 2001 to 2020 from the perspective of the three spatial types (ecological space, production space, and living space), considering both natural and human factors. The results showed that: (1) From 2001 to 2020, the area of living space in the BTH region increased the fastest, by 7661.709 km² (49.76%), while both ecological space and production space areas decreased. (2) From 2001 to 2020, the overall NPP in the BTH region showed a fluctuating upward trend, with a significant decrease in NPP in the southeastern plains around urban centers. The average NPP and annual growth rates exhibited a pattern of ecological space > production space > living space. (3) Results based on the Geodetector and Generalized Additive Model showed that the factors influencing NPP changes varied greatly across the three spatial types. Specifically, human activities were the dominant factors in living spaces, while natural factors dominated in production and ecological spaces. The results of this study contribute to a deeper understanding of vegetation growth changes and the underlying mechanisms in the Jing-Jin-Ji Region.

Urban green space ecosystems could regulate thermal environmental problems, and play a crucial role in mitigating urban heat island (UHI) effects. We analyzed the relationships between the leaf area index (LAI), vegetation coverage (VC), gross primary productivity (GPP) of urban green spaces and the land surface temperature (LST) in Guangzhou, and explored how UHI mitigation function would be affected by the urban ecosystem quality. The results showed that there were strong negative correlations between LAI, VC, GPP and LST, with Pearson correlation coefficients being -0.73, -0.886, and -0.892, respectively. The correlation coefficient between ecosystem quality index (EQI) and LST was -0.831, suggesting that the quality improvement of urban green spaces would alleviate UHI. Both LST and EQI of Guangzhou exhibited pronounced spatial heterogeneity. Liwan, Haizhu, and Yuexiu districts were not only the industrial agglomeration belts but also the core areas of UHI in Guangzhou. Their ecosystem quality was relatively poor (with EQI values rating good or below). In contrast, ecosystem quality of Zengcheng and Conghua districts was relatively good, with the EQI of both districts being at “good” level or above. Therefore, the UHI effects of those districts were relatively weak. When the regional EQI was low, green space ecosystems were difficult to reduce the LST through a large amount of transpiration, evaporation and photosynthesis, showing weak regulatory functions of the UHI effect. The cooling effect of green spaces would be quite noticeable only if the ecosystem quality of green spaces attained a specific standard. When the regional EQI exceeded 55, the cooling effect was relatively obvious. Moreover, when the EQI was greater than 75, the cooling effect was the most remarkable. In the future planning and construction of urban green space ecosystems, efforts should focus on expanding the area of urban green spaces and enhancing the ecosystem quality, which would help strengthen the regulatory function of urban green space ecosystems in dealing with UHI effect.

The ecological risks in the Hexi Corridor cities are severe. It is crucial to understand the ecological resilience of cities for sustainable development. Based on the “Resistance-Adaptability-Recovery” model, we assessed the temporal and spatial variations of ecological resilience in the cities of the Hexi Corridor. We explored the coordination types and evolutionary paths of ecological resilience using coupling coordination degree model. The results showed that the resistance initially increased and then decreased, showing a spatial pattern of low in the northwest and high in the southeast. The degree of adaptability showed a rising trend, exhibiting a spatial pattern of high in the center and low on the both sides. Recovery showed a declining trend, presenting a distribution pattern of high in the northwest and low in the southeast. The overall ecological resilience showed a trend of rising, falling and then rising again, with a distribution characterized by “high-high aggregation and low-low aggregation”. Hexi Corridor cities were primarily categorized as weak recovery and strong recovery types, with overall ecological resilience in a moderately coordinated stage. The coordination degree exhibited a trend of rising, falling, and then rising again, centered around Zhangye and Jinchang, decreasing towards the northwest and southeast. Ecological resistance was negatively correlated with the resilience of Hexi Corridor cities.

Assessing the supply and demand of urban ecosystem services at the community scale is vital for enhancing urban ecological governance and management. Based on multi-source data such as remote sensing and land survey data, we quantified and mapped the supply and demand of air purification, temperature regulation, and recreational services at community level in Jiading District of Shanghai by applying relevant indicators and performing spatial analysis. The results showed that: (1) The supply of air purification, temperature regulation, and recreational services exhibited significant variations across community. The spatial patterns of different services were generally consistent, characterized by higher supply in the north and lower supply in the south of the district. (2) The spatial pattern of demand varied among the three aforementioned ecosystem services. The demand for air purification services was higher in the northern and southern regions and was lower in the central regions. The demand for temperature regulation and recreational services was higher in the southern and central urban areas and lower in the northern and surrounding suburban areas. (3) The overall ecosystem services of each community were at a state of mismatch between supply and demand, with the degree of mismatch between supply and demand for temperature regulation being the most serious. The match between supply and demand of the three types of ecosystem services generally showed a spatial distribution pattern of “superior in the north and secondary in the south, poor in the center and good in the periphery”, but there were certain discrepancies in the spatial distribution of supply and demand matching of the three ecosystem services. These findings can offer valuable insights for the spatial allocation, structure design, and management of ecological spaces, ultimately meeting the demands of urban residents for a pleasant living environment.

Assessing the sustainability of eco-economic systems at the household level is vital for improving the integration and long-term viability of natural-ecological-social systems. Based on the emergy analysis method, we deve-loped an emergy indicator system that covers natural, economic, and social dimensions. Using this system, we assessed the sustainability of rural household eco-economic systems in the rural areas of northwestern Liaoning Province, and compared the differences in eco-economic systems among households with different livelihood types. The results showed that rural household systems in northwestern Liaoning had a generally low level of sustainable deve-lopment (ranging from 0.05 to 1.75). Environmental load rate was relatively high, with 60% of households facing moderate to severe environmental loads. Economic investments were often inefficient, with 17% of households showing a trade deficit. In terms of sustainability across livelihood types, the ranking was as follows: balanced type (0.586) > planting type (0.417) > breeding type (0.410) > working type (0.406) > business type (0.335). To promote sustainable rural development in northwestern Liaoning, it is recommended to encourage residents to participate more in agricultural production, improve resource efficiency, and adopt low-carbon lifestyles. Additionally, government agencies should increase funding and support for waste management, strengthen farmland protection and ecological conservation incentives, and take comprehensive measures to drive sustainable rural growth.

Urban forest is an important carbon sink. Soil respiration plays a crucial role in the carbon cycling of urban ecosystems. Currently, the research on forest soil respiration is mostly focused on natural forests, less is known on soil respiration of urban forest. Here, we explored the characteristics and influencing factors of soil respiration in different urban forests, including Pinus tabuliformis, Picea koraiensis, Populus alba × P. berolinensis, and Ginkgo biloba stands in Shenyang of China. Soil respiration rate, soil physical and chemical properties and enzyme activities in each stand were measured from April to October 2023. The results showed that: (1) Soil respiration rates across the four forest stands exhibited a single-peak seasonal variation, with higher values observed in summer and lower values in spring and autumn. (2) There were significant differences in soil respiration rates among the different stands (P<0.05), with the highest value being recorded under the G. biloba stand (2.82±0.19 μmol·m^-2·s^-1). (3) Soil respiration rates of the four forest stands were significantly exponentially correlated with soil temperature (P<0.001). For P. koraiensis and P. alba × P. berolinensis stands, soil respiration rates were significantly linearly correlated with soil moisture (5 cm) (P<0.01). (4) Soil respiration rate was positively correlated with the contents of soil organic matter and ammonium, the activities of sucrase, urease and polyphenol oxidase (P<0.05), while it was negatively correlated with soil pH and nitrate content (P<0.05). Hierarchical partitioning analysis indicated soil temperature was the most important factor affecting soil respiration rate. Our results can enrich the theory of terrestrial soil carbon cycle and provide a scientific basis for the construction and management of urban forests in northern regions under the context of climate change.

To clarify the impacts of stockpiled construction waste on soil environment of coastal cities, five land use types were selected: construction waste stored for six months, construction waste stored for 12 months, wasteland, long-term cultivated farmland and re-cultivated farmland in Lingkun City, Wenzhou, Zhejiang Province. We analyzed the differences and correlations of soil environmental factors and microbial community structure in different habitats. The results showed that the accumulation of construction waste significantly increased soil pH and decreased the concentrations of organic carbon, active organic carbon, total nitrogen, organic nitrogen, active organic nitrogen and hydrolyzed nitrogen. With the accumulation of construction waste, the composition of soil microbial community changed, and Proteobacteria and Firmicutes replaced Actinobacteriota as the dominant phyla. The variation of soil environmental factors caused by the accumulation of construction waste reduced soil microbial abundance. The redundancy analysis results showed that soil pH, salt, total nitrogen, total phosphorus, and dissolved organic carbon contents were the main factors influencing of soil microbial community. Re-cultivation helps restore soil environmental factors and microbial community composition. This study contributes to better understanding of the impacts of construction waste on the environment and the microbial mechanism in the process of urbanization, and demonstrates the positive effect of re-cultivation as a means of restoration on the damaged soil environment.

Urban road dust has received widespread attention due to its environmental and health risks. In this study, a total of 38 campus road dust samples were collected from kindergartens, elementary schools, and colleges in Beijing. By measuring the contents of Cd, Co, Cr, Cu, Ni, Pb, Ti, V, and Zn, we analyzed the contamination characteristics, sources, and health risks. The results showed that heavy metals in Beijing campus road dust displayed heavy pollution. Among them, Cd showed the highest level of pollution, followed by Zn, Cu, Pb, Co, Cr, Ni, V and Ti. The sources of heavy metals in campus road dust mainly included industrial sources (33.33%), traffic sources (45.93%), and natural sources (20.74%). Uncertainty assessment of health risk was carried out using Monte Carlo simulation in conjunction with the health risk model of the U.S. Environmental Protection Agency. The results showed that heavy metals in road dust had significant carcinogenic risk, and that the health risk of children was higher than that of adults in all cases. Cd was the preferred pollutant to be controlled in campus road dust. Traffic sources were the preferred source of risk to be controlled.

During urban ecological construction, a systematic understanding and management of allergenic plants and allergenic pollens have become crucial. The indiscriminate introduction of plant species without considering allergenic pollens may lead to an increasingly serious urban allergenic pollen problem. We reviewed the researches on the sources and monitoring methods of allergenic pollens, the atmospheric transport characteristics, as well as its potential integrated impacts and risk assessment following a logical structure of pattern-process-effect. Firstly, we sorted out the source plants of allergenic pollens and summarized the monitoring techniques for allergenic pollens. Secondly, we summarized the methods for identifying the flowering periods of allergenic plants based on technologies such as remote sensing and deep learning, centering on the relationship between the growth and developmental stages of plant flowering and environmental factors. Thirdly, we outlined the methods of prediction of the concentration of allergenic pollens, discerned the two distinctive modes of pollen impacts and transport in full bloom and non-full bloom periods, and summarized the comprehensive risk assessment methods of allergenic pollens. Finally, we pointed out the shortcomings in prediction, migration simulation, and health assessment of urban allergenic pollens, and prospected future research directions and potential applications. This review is of great significance for improving the prevention and control level of urban pollen allergies and promoting urban ecological construction.

To explore the dynamics of coastal erosion and prevention measures, Landsat series remote sensing data from 1985 to 2023 were used to create a time series of the intertidal zone in Yancheng Nature Reserve. Coastal accretion, erosion dynamics, and the changes in land use types across different years were analyzed. The results showed that: (1) Yancheng Nature Reserve shifted from an accretion-type coast (1988-2012) to an erosion-type coast (2012-2023). (2) Coastal accretion mainly showed a trend of gradual slowdown, reaching a peak rate of 521.8 hm²·a^-1 between 1997 and 2000. Coastal erosion showed a trend of first weakening and then strengthening, with the slowest erosion between 2003 and 2009 at a rate of 0.7 hm²·a^-1. (3) The area of wetlands affected by human activities and the area of Spartina alterniflora wetlands increased gradually at mean annual rates of 501.4 and 150.2 hm²·a^-1, respectively. (4) In terms of coastal accretion, S. alterniflora communities and areas affected by human activities accounted for 69.7% and 13.0% of the total accretion area, respectively. In comparison, S. alterniflora communities and areas affected by human activities accounted for 34.4% and 22.7% of the total erosion area, respectively. S. alterniflora played a significant role in promoting accretion and protecting beach in Yancheng Nature Reserve. Efforts should be made to strengthen early warning mechanisms and explore optimal measures to combat coastal erosion in Yancheng.

Caohai is a typical plateau shallow freshwater lake located in Guizhou Province. In recent years, the environmental problems in Caohai have become increasingly severe. The sharp decline in submerged vegetation leads to a significant deterioration in ecosystem quality and service functions. With the MIKE21 numerical model, we investigated the impacts of wind disturbance on the wetland restoration strategies for Caohai. By simulating hydrodynamic characteristics under different wind conditions, we analyzed the changes in current speed and water quality before and after the degradation of submerged vegetation. The results showed that the degradation of submerged vegetation led to a significant increase in current velocity, with an average increase of 59%, and a maximum velocity reaching 0.037 m·s^-1 under average wind conditions. Additionally, wind disturbance caused sediment resuspension and increased the concentrations of phosphate and COD in the water, thereby exacerbating eutrophication and pollution. These findings demonstrate that wind disturbance has negative impacts on the recovery of submerged vegetation. Therefore, wetland restoration strategies should comprehensively consider reducing the impact of wind disturbance on hydrodynamics and water quality, adopt integrated measures to protect and restore submerged plants, and enhance the stability and service functions of wetland ecosystems.

To explore the potential for the resource utilization of sediment in the Yellow River and to clarify the physical, chemical and biological responses to improvement measures, we conducted a field experiment with dredged sediment from Wuhai Lake in the Inner Mongolia section of the Yellow River Basin as the research object and maize as the planting crop. The treatments included sediment application, fertilizer application, growth-promoting bacteria application, biochar (rice husk biochar/wheat straw biochar) application, application of microbial agent combined with biochar, and application of microbial agent combined with biochar and covered with hydrophobic sand. Soil samples of the rhizosphere of maize were collected at the pre-planting, seedling, jointing, and maturity stages. Soil moisture, nutrient content and enzyme activity were measured. The results showed that the application of rice husk biochar and wheat straw biochar could improve soil moisture and nutrient content. The improvement effect increased with the increases of dosage (0.5%-4%), and rice husk biochar was superior to wheat straw biochar. Compared with the single application of fertilizers (F), the application of rice husk biochar (with a dosage of 0.5%-4%) increased soil water content by 1.7%-5.5%, 0.3%-5.0%, 0.9%-4.4%, and 0.4%-3.4%, and increased soil organic matter content by 14.0%-156.1%, 18.7%-159.7%, 26.0%-178.6%, and 19.2%-168.9% in the four sampling periods, respectively. An appropriate amount (0.5%) of biochar application significantly enhanced the activities of four enzymes (with rice husk biochar having a better effect), but the enhancement effect was weakened when the dosage increased to 2%. Compared with the application of biochar, the application of microbial agent combined with biochar decreased soil pH, but increased water content, ammonium nitrogen, available phosphorus, and organic matter contents. The hydrophobic sand cover increased the water content, available phosphorus, and organic matter content, but decreased soil pH, conductivity, ammonium nitrogen, and available potassium content. The Pearson correlation analysis and principal components analysis revealed that the improvement of soil physicochemical properties and the increase of nutrient content were conducive to improving enzyme activities, but high soil pH during the maturity stage would inhibit the catalase activity. Therefore, the application of biochar, especially microbial agent combined with biochar treatment, can effectively improve nutrient content and enzyme activity of the sediment, which is an effective way to improve its quality and promote resource utilization.

To explore the dynamics in phytoplankton community structure and functional groups in the Yangshui River that located in the phosphate rock-polluted region of Guizhou Plateau, we investigated phytoplankton and water environment indicators during the dry and wet seasons from 2020 to 2022. Functional group classification, diversity index, evenness index, Spearman correlation analysis, redundancy analysis (RDA), non-metric multidimensional scaling analysis (NMDS), permutational multivariate analysis of variance (PERMANOVA), and stepwise regression analysis were employed to analyze the succession characteristics of phytoplankton community during the dry and wet seasons, as well as the dynamics of phytoplankton functional groups. We further identified the key environmental factors affecting phytoplankton functional groups in Yangshui River. The results showed that: (1) Species composition of phytoplankton in Yangshui River showed significant temporal and spatial variations. 47 species of phytoplankton belonging to 6 phyla were detected. Bacillariophyta accounted for the highest proportion (44.68%), followed by Chlorophyta (31.91%). The total cell abundance of phytoplankton was 1.05×10⁷ cells·L^-1, and the total biomass was 6.55 mg·L^-1. The average cell abundance and biomass increased year by year from 2020 to 2022, being higher in the wet season than in the dry season. (2) 18 phytoplankton functional groups were identified, among which B, D and MP were the common dominant functional groups, and their representative species belonged to Bacillariophyta. In terms of time series, the changes of dominant functional groups from 2020 to 2022 were D/MP/B/S1/X₃ in 2020, MP/D/Y/S1/B in 2021, and MP/D/C/B/P/S1 in 2022. In terms of seasonal differences, MP/D/B/C/S1/X₃ were the dominant functional groups in the dry season, while MP/D/B/S1/Y/P were the dominant ones in the wet season. Spatially, the dominant functional groups shifted from MP/D/B (YS1, upstream)→MP/D/B (YS2)→MP/D/B/S1/Y(YS3, midstream)→MP/Y/C/B/D/S1 (YS4, downstream). (3) The analysis of environmental factors showed that phosphorus was the limiting factor of phytoplankton growth in Yangshui River. The results of RDA analysis showed that the eigenvalues of the first and second ordination axes were 26.82% and 5.76%, respectively. Dissolved oxygen was the main environmental factor affecting the phytoplankton functional groups in Yangshui River. Results of stepwise regression analysis showed that there were significant differences in the adaptation mechanism and ecological needs of different functional groups to dissolved oxygen. During the dry season, the MP functional group had stronger correlation with the B functional group. In the wet season, water temperature and D functional group were significantly correlated with B functional group, while total phosphorus was weakly correlated with B functional group. The ratio of nitrogen to phosphorus may be the key factor for the growth of MP functional group. The results provide an important scientific basis for the long-term management of water resources, and water ecological protection and governance of Yangshui River.

Guangxi Shankou Mangrove National Ecological Nature Reserve is facing a severe invasion by Spartina alterniflora and urgently needs to be eradicated and restored. We conducted a field experiment to examine the effects of three concentrations of herbicide-spraying groups \[i.e., 50.0 (D1), 62.5 (D2), 75.0 (D3) g·L^-1 of imazapyr herbicide\] on S. alterniflora, from April 2022 to April 2023 on the intertidal flat of Yingluo Bay, Guangxi, China. During the experiment, eight samplings were taken to monitor the changes in the macrobenthos community. Multiple community indices were used to evaluate the impacts of imazapyr on the macrobenthos community. In total, 7 phyla, 8 classes, and 44 species of macrobenthos were captured, with the mollusks and arthropods species being more abundant. The species composition of community in each treatment group fluctuated greatly throughout the entire investigation period, while there was no regular trend affected by pesticide application. The density and biomass of the groups D1 and D2 increased in the early stage. The number of dominant species in the three herbicide-spraying groups remained stable or even increased in the early stage, but showed a downward trend in the middle and late stages, with Paracleistostoma depressum as the dominant population. The difference in the turnover rate of dominant species among the four treatment groups was not significant in the early stage, but significant in the middle and late stages. The species turnover index did not show significant phased changes, with substantial species gain and loss. The species migration index showed that the difference in the number of species migrating in and out was relatively small for most of the time. The macrobenthos pollution index indicated the habitat qualities in vast majority of sampling times were clean. Based on a comprehensive assessment, the ecological impact of using the imazapyr herbicide solution with a concentration of 50.0 g·L^-1 and a dosage of 60 L·hm^-2 to remove Spartina alterniflora on the macrobenthic community was acceptable.

The landscape patterns of estuarine wetlands are strongly affected by human activities. Therefore, investigating the impacts of human activity intensity on the landscape pattern of estuarine wetlands is of great significance for improving wetland conservation. In this study, we analyzed the spatial patterns of the Xiaoqing River estuary wetland landscape during 2013 to 2023 by using remote sensing images, night light data, and population data. We quantitatively analyzed the response of the wetland landscape pattern to human activity intensity based on the human activity intensity model and the gradient variations of the landscape patterns of the Xiaoqing River estuary wetlands along with human activity intensity. The results showed that during the past ten years, the total area and landscape diversity of the Xiaoqing River estuary wetlands showed a trend of initial decline and subsequent increase. The degree of landscape fragmentation and aggregation showed an initial rise followed by a decrease, whereas there were no changes in landscape connectivity. The spatial variations of human activity intensity in the Xiaoqing River estuary were substantial. The proportion of constructed wetlands with moderate and relatively high intensity of human activity was the largest, while the proportion of natural wetlands with high intensity of human activity was the smallest. There was a strong association between human activity intensity and wetland landscape indices in the Xiaoqing River estuary. The intensity of human activity had a positive correlation with PD, SHEI, SHDI, and CONTAG, and a significantly negative correlation with COHESION and AI. In conclusion, the spatial differences in human activity intensity determined the development direction of the landscape pattern of the Xiaoqing River estuary wetlands. Our findings can aid in decision-making about the management of human activity and the preservation of wetlands in the Xiaoqing River estuary.

As a genuine medicinal material in North China, the ecological cultivation of Forsythia suspensa is a critical concern in the current production of medicinal materials. We investigated the morphological phenotypes, module quantities, and the module distribution pattern of F. suspensa with different numbers of main branch formed under ecological cultivation using hierarchical survey, as well as their impacts on the yield and quality. We found a substantial morphological plasticity in the crown width of F. suspensa, of which those with three to five main branches had a 1.64-fold difference compared to that with one branch (P<0.01). The plasticity of plant height and ground diameter was relatively small (P>0.05). The module numbers of branches, leaves, flowers, and fruits of F. suspensa exhibited high plasticity. According to the distribution pattern of F. suspensa modules, the branches of F. suspensa were distributed within 60-160 cm in the vertical direction and within the middle layer of the canopy in the horizontal direction. In terms of reproductive modules, the distribution patterns of flowers and fruits were basically the same as those of its branches. However, there were significant differences in fruit-setting rates at different locations. Vertically, the fruit-setting rate in the middle (60-140 cm) of the crown was higher than that in the upper and lower layers, with the highest rate at 80-100 cm (55.2%). Horizontally, the fruit-setting rate in the middle and outer (80-140 cm) of the crown was significantly greater than that in the inner layer, with the highest rate at 80-100 cm (69.4%). F. suspensa with one main branch and that with five main branches had distinct advantages in fruit yield, which are suitable for intensive and extensive management, respectively. In addition, F. suspensa with one main branch had the highest contents of volatile oil and forsythin, and the content of forsythoside A did not show significant difference from the highest value found in other types with different main branch numbers. Taken together, F. suspensa with one main branch is an excellent type among the five types with different main branch numbers, embracing higher economic benefits and medicinal value.

This study aimed to understand the effects of nitrogen (N), phosphorus (P) and potassium (K) deposition that were caused by human activities on plant leaf nutrient traits in alpine grassland ecosystem. A multiple-nutrient (N, P, K) addition experiment with eight treatments was carried out in Bayinbrooke grassland. By measuring leaf C, N and P contents of six common species, we explored the response patterns of leaf nutrient traits to nutrient addition at the species, functional group, and community levels. The results showed that: (1) N addition significantly increased leaf N content, and P addition significantly increased leaf P content of the six species. The effects of mixed nutrient addition on leaf C, N and P contents were complex. (2) Nutrient addition significantly affected the N and P contents in leaves of different functional groups. After N addition, leaf N content in grasses increased significantly by 66.4%. After the addition of P, NP and NPK, the contents of N and P in the leaf of grasses increased significantly. After P addition, the leaf P content in legume increased significantly by 98%. (3) Different nutrient addition treatments significantly affected leaf N and P content at the community level. Under the addition of P, NP, PK, and NPK, leaf N and P contents increased significantly, especially for leaf P content. However, N, K, and NK addition had no significant effect on leaf N and P content. Principal component analysis revealed that soil organic matter, total N, total P content and soil pH were the key factors affecting the variation of leaf C, N and P content at the community level. Among those factors, soil total P was the most critical one, followed by soil organic matter and total N, and the influence of soil pH was relatively limited.

Understory vegetation plays a key role in regulating forest structure and function. To explore the effects of uneven-aged mixed silviculture on understory vegetation, we investigated species composition of understory in pure Pinus massoniana plantation (PP), uneven-aged mixed plantation (MP) of Pinus massoniana and Castanopsis hystrix (MP), and multiple species uneven-aged mixed plantation (MMP). By combining field investigations with laboratory analyses, we compared the differences in understory species composition among different forest types, and further explored the diversity of shrub and herb species in the understory, as well as the changes in functional groups and their relationships with environmental factors. We found that species richness, Shannon and Simpson indices of herb layer in MP, as well as species richness and Shannon index of shrub layer and the Shannon and Simpson index of herb layer in MMP increased significantly (P<0.05) compared with those in PP. Moreover, the species richness of the fern functional group in MP and the woody plant functional group in MMP significantly increased compared with those in PP (P<0.05). Soil NH₄⁺-N and C/P were the primary factors driving species composition of shrub layer, while slope and soil NH₄⁺-N were the primary habitat factors influencing species composition of herb layer. Additionally, soil TN was the most important habitat factor affecting plant functional groups. In summary, introducing broadleaf tree species into the uneven-aged mixed silviculture of Pinus massoniana plantations could enhance the richness and diversity of understory plants. Such changes were co-regulated by the alterations of soil properties, tree characteristics, and microenvironment under different silviculture patterns.

Broadleaved transformation is one of the key directions for sustainable management of Pinus massoniana forests, but little is known about the changes of soil stoichiometric characteristics. Here, we investigated soil stoichiometric characteristics across pure Pinus massoniana forest (CK, 40-year-old), Pinus massoniana (40-year-old) and Cinnamomum camphora (10-year-old) mixed forest (X1, transformed from pure Pinus massoniana forest), Pinus massoniana (40-year-old) and Cinnamomum camphora (20-year-old) mixed forest (X2, transformed from pure Pinus massoniana forest), and 30-year-old Cinnamomum camphora forest (X3). We examined the vertical characteristics of soil organic carbon (C), total nitrogen (N), total phosphorus (P) and their stoichiometric ratios at soil depths of 0-20, 20-40, 40-60 cm. The results showed that: (1) Soil C, N, P contents and their stoichiometric ratios decreased with increasing soil depth. (2) Soil C, N contents and C∶N significantly increased with increasing transformation time, while soil P content remained relatively stable. Soil C∶P and N∶P in CK were significantly lower than those in other stands (P<0.05), showing a trend of mixed forest (X1 and X2) > broadleaved forest (X3) > coniferous forest (CK). (3) Forest type significantly affected soil C, N, P contents and their ecological stoichiometric ratios (P<0.05). Soil depth had significant effect on soil C and N contents (P<0.05). However, forest type and soil depth showed no interaction in affecting soil N and P contents. (4) There were significant positive correlations among soil C, N and P contents. Soil C and N∶P, soil N and C∶P, and soil P and C∶N showed significant positive correlations. Overall, the broadleaved transformation of Pinus massoniana forest increased soil C and N contents and the ratios of soil C∶N, C∶P, and N∶P.

Shaniodendron subaequale, a tertiary relict species endemic to China, is designated as a nationally protected wild plant species due to its significant evolutionary status bridging gymnosperms and angiosperms. The plant-associated microbiome is considered the second genome of plants. Phyllosphere bacteria significantly influence plant growth and environmental adaptability. The characteristics and geographical distribution patterns of the bacterial community in S. subaequale phyllosphere are unknown. This study aimed to investigate the composition and diversity of S. subaequale phyllosphere bacteria in its primary distribution areas, as well as the influences of geographical features, soil physical and chemical properties, and leaf physiological and biochemical indices on phyllosphere bacterial composition and diversity. Leaves of S. subaequale from six native sites were collected. The phyllosphere bacterial community was determined by high-throughput sequencing technology. Moreover, leaf physiological and biochemical indices and soil physical and chemical properties in each site were measured. The results revealed a high relative abundance of Sphingomonas, Massilia, and Amnibacterium in the phyllosphere of S. subaequale in all the six sites. Leaf bacterial composition was significantly distinct in different sites. In particular, the phyllosphere bacterial composition in plants from Huzhou City, Zhejiang Province was significantly different from that of other sites. The phyllosphere bacterial diversity was greatly affected by the latitude differences among the sites. However, the effects of leaf physiological and biochemical characteristics and soil physical and chemical properties on the bacterial composition and diversity in the phyllosphere of S. subaequale were more pronounced. This study reported the presence of a wide range of bacterial taxa in S. subaequale phyllosphere. Moreover, there were significant differences in the phyllosphere bacterial composition and diversity in S. subaequale across different sites, which were mainly regulated by leaf defense-related metabolites and soil nutrients. The results provide a theoretical basis for preserving the environment of microecology in S. subaequale and thus strengthening species conservation.

Cadmium (Cd) pollution is an important environmental problem. Quercus variabilis has stronger tolerance to heavy metals than other tree species. To clarify the molecular response of Q. variabilis to Cd stress, high-throughput sequencing of the transcriptome was performed on leaves of current-year seedlings subjected to 15, 30, and 90 days of stress with CdCl₂ solutions at concentrations of 50, 100, and 150 mg·L^-1. Differentially expressed genes (DEGs) were identified. Subsequent analyses of DEGs included gene annotation, gene enrichment analysis, weighted gene co-expression network analysis (WGCNA), and transcriptional regulatory network analysis, aimed to identify key genes associated with Cd tolerance in Q. variabilis. The results showed that a total of 23930 DEGs were identified after 15 days of Cd stress. Gene Ontology (GO) enrichment analysis indicated that these genes were predominantly enriched in terms related to “chromosome regulation activity” and “energy metabolism process”. A total of 15675 DEGs were identified after 30 days of Cd stress. GO enrichment analysis demonstrated that these genes were primarily enriched in “ion channel activity”, “cell division regulation”, and “enzyme activity”. A total of 12701 DEGs were identified after 90 days of Cd stress. GO enrichment analysis indicated that these genes were predominantly enriched in “transmembrane transporter activity”. The WGCNA revealed that the blue and yellow modules exhibited the strongest correlation with Cd stress. Glycine Cleavage System P Protein (GCSPP), Caffeoyl-CoA O-methyltransferase (CCOM), and DNA Damage Repair/Tolerance Protein DRT102-like (DDRP) played a key role in the blue module. The ribosome biogenesis protein WDR12 homolog (RBP) played a key role in the yellow module. This study screened DEGs related to Cd tolerance in Q. variabilis, among which four genes play a pivotal role in Cd tolerance of Q. variabilis, laying a foundation for elucidating the molecular mechanisms of Cd tolerance and detoxification in Q. variabilis.

Cadmium (Cd) is a common heavy metal pollutant, which has a serious toxic effect on the growth and development of rice. Consumption of rice is the main way of Cd intake for human. Although the accumulation of Cd in rice has attracted global attention, little is known about the effects of arbuscular mycorrhizal fungi (AMF), one of the microorganisms most closely related to the rhizosphere, on the accumulation of Cd in rice. In this study, Glomus mosseae 171 (GM171) and G. mosseae 180 (GM180) were selected to examine their effects on rice growth (plant height, root length, biomass), Cd concentration in pore water, and Cd concentration in different tissues of rice (root, stalk, leaf, seed, hull, bran) at different growth stages in a pot experiment. Results showed that inoculation of GM171 and GM180 did not affect plant height, root length and biomass of rice. Different AMF strains had different effects on Cd concentration in pore water at different rice growth stages. AMF inoculation significantly promoted Cd accumulation in both the underground and aboveground tissues of rice. Compared with CK, inoculation with GM171 and GM180 increased root Cd concentration by 27% and 11%, respectively, and increased grain Cd concentration by 28% and 24%, respectively. The root contained the largest proportion of Cd in the whole plant, reaching to ≥50%. In summary, AMF inoculation promoted the absorption of Cd by rice roots and the migration of Cd to the aboveground tissues, resulting in increasing Cd concentration in the aboveground tissues and higher health risk to human. This study provides scientific reference for the remediation of Cd pollution in croplands.

To reveal the concentrations of iron (Fe), manganese (Mn), magnesium (Mg), calcium (Ca), zinc (Zn), copper (Cu), fluorine (F) and aluminum (Al) in the soil and tea leave in the tea-producing areas of Guizhou, we analyzed the concentrations, bioconcentration factors and influencing factors of these mineral elements in the soil and tea, as well as the intake of those elements by tea drinking. The results showed that the average concentrations of eight elements in soils were 37257 (Fe), 539 (Mn), 3696 (Mg), 1130 (Ca), 97 (Zn), 33 (Cu), 697 (F) and 58500 (Al) mg·kg^-1, respectively. The concentrations of Mn, Ca, and Mg were significantly lower than the background values of soils in Guizhou Province due to severe soil acidification (with average pH of 4.36) in tea garden. The average concentrations of Fe, Mn, Mg, Ca, Zn, Cu, F, and Al in tender tea leaves (one bud and two leaves) were 82, 726, 1874, 2291, 36, 11, 57 and 506 mg·kg^-1, respectively. The concentrations of Mn, Mg, Ca, and Al in tea leaves were at a high level in China, while the Fe, Zn, and Cu concentrations of tea leaves were generally low. The average bioconcentration factors of those eight elements in tea leaves ranged from 0.003 to 2.549. The bioconcentration factors of Ca and Mn were the highest, followed by Mg, Zn, Cu, F and Al, and Fe was the lowest. Tea drinking can supplement 18%-20% of Mn requirements of human body, but the intake of F, Mg, Fe, Ca, Zn and Cu through tea drinking is limited. We should be cautious about the risk of Al intake through tea drinking, which accounts for up to 6% of the tolerable intake.

To investigate the content, spatial distribution characteristics, and ecological risk status of soil heavy metals in different geological backgrounds, we selected three townships in Xingyi City, Guizhou Province, which have high background values of soil heavy metals, as the study area, and divided them into three geological background zones (carbonatite zone, carbonatite interspersed with clastic rock zone, and clastic rock zone). We analyzed the contents and spatial distributions of soil heavy metals As, Cd, Cr, Cu, Ni, Pb, and Zn in 187 soil samples from different geological background areas. The pollution index and potential ecological risk index were used to evaluate the level of soil pollution and ecological risks. The results showed that: (1) compared with the soil background values in Guizhou Province, all seven heavy metals were enriched in the carbonatite zone, especially for As and Cd. As, Cr, Cu, Ni and Zn were enriched in the carbonatite interbedded with clastic rock zone except for the depletion of Cd and Pb. All the seven heavy metals in the soil in the clastic rock zone showed depletion. (2) The spatial distribution of soil heavy metals was constrained by the geological background as well as the mining area. The spatial distribution pattern of As, Cd, Pb and Zn was similar, with their contents showing the carbonatite zone > carbonatite interbedded with clastic rock zone > clastic zone, which was mainly controlled by geological background. The spatial distribution of Cr, Cu and Ni was also similar, showing the carbonatite with clastic rock zone > carbonatite zone > clastic zone, which was mainly affected by Daji Mountain uranium polymetallic mining area in the northwest of Qishe Town. (3) The results of pollution index and ecological risk evaluations revealed Cd and As were the primary pollutants, which had a high contribution to the ecological risk of the three geological background zones. Overall, the degree of heavy metal pollution and potential ecological risk exhibited a pattern of carbonatite zone > carbonatite interbedded with clastic rock zone > clastic zone. Spatially, the areas with serious heavy metal pollution and strong risk were mainly distributed in the carbonatite zone in the south of Zhuchangping Town.

The yellow-breasted bunting (Emberiza aureola) is a songbird that was once widely distributed across Eurasia. In recent years, its conservation status has continuously risen, and it has become a globally “Critically Endangered” species. In China, it is listed as a National First-Class Key Protected Wild Animal. In recent years, the yellow-breasted bunting has experienced a dramatic decline, which was once attributed to the illegal hunting in eastern China. However, the potential influence of climatic factors on the yellow-breasted bunting population in the breeding areas has been neglected. In this study, we applied the theory of climatic ecological niche by combining climatic variables and distribution points in the breeding areas of yellow-breasted buntings. This approach allowed us to predict, based on the Maximum Entropy Model (MaxEnt), the potential breeding area suitable for yellowbreasted buntings in the present period, as well as the trend of suitable areas in two future periods, the 2050s and 2070s, under the backdrop of climate change. The results showed that: (1) The main variables affecting the distribution of the breeding area of the yellowbreasted bunting were the rainfall in the warmest season (a contribution rate of 35.4%), the mean annual air temperature (a contribution rate of 35.3%), and the coefficient of seasonal variation of temperature (a contribution rate of 12.4%). (2) The total area of suitable breeding areas in the current period is 11.3118 million km², mainly distributed in Russia (77.93%), followed by China (10.52%), Mongolia (5.30%), Finland (3.22%), and other countries such as Sweden (3.03%). (3) Under the background of future climate change, the area of suitable breeding grounds will continue to shrink. Compared with the current period, the suitable area will decrease by 15.50% in the 2050s and 32.99% in the 2070s. Among them, China will see a significant reduction in suitable breeding areas, with a decline of 79.22% in the 2050s and 91.39% in the 2070s. (4) The centroid of the breeding range is shifting northeastward. The suitable area is shifting towards higher latitudes, while that in the low-latitude areas is shrinking, with contraction in western part of Europe and expansion in Northeastern Asia. Our results suggest that climate change poses a significant threat to the yellow-breasted bunting. Hunting bans alone are insufficient for the conservation and management of this species. Global efforts to curb warming are essential to mitigate the negative impacts of climate change on endangered species.

Climate warming and increased nitrogen deposition are significant manifestations of global environmental change, which have important impacts on the structure and function of terrestrial ecosystems. Alpine meadows, as the most widely distributed vegetation type on the Tibetan Plateau, are extremely sensitive to global changes. Research over the past few decades has suggested that plant diversity is a key driver of the functional performance of alpine meadow ecosystems, but the roles of belowground biodiversity and the interactions between aboveground and belowground components in maintaining ecosystem stability have been overlooked. We review the research progress on the changes of plant diversity and soil biodiversity in alpine meadows under the context of climate warming and nitrogen deposition, from the perspectives of species diversity and functional diversity. Currently, there are some shortages in current research on the aboveground-belowground interactions in alpine meadows under climate warming and nitrogen addition, as well as multi-factor interaction experiments in the context of global climate. It is recommended to conduct ecological and molecular biological studies to quantify the threshold judgments of the effects of various components of the aboveground-belowground system in alpine meadows under different gradients and temporal scales of warming and nitrogen addition, as well as their feedback mechanisms. This could provide a theoretical basis for maintaining the multifunctionality of ecosystems and protecting alpine ecological regions in the context of climate change.

With the intensification of global climate change, the area, intensity, and frequency of droughts continue to increase. The content and composition of root exudates (such as sugars, amino acids, and organic acids) will change, thereby affecting carbon and nitrogen cycling in forests. However, how the content and composition of root exudates vary with drought intensity and tree species, as well as the mechanisms of root exudates in mediating carbon and nitrogen cycles under drought conditions, remain unclear. Therefore, we first summarized the effects of drought intensity on the content and composition of forest root exudates and the responses of root exudates across different tree species. Secondly, the mechanisms of root exudates on soil carbon and nitrogen cycles under drought conditions were analyzed from two aspects of soil carbon and nitrogen. Finally, it is suggested that future research should focus on strengthening the following four aspects: (1) the effects of different drought intensities and recovery on the composition and content of forest root exudates; (2) the soil priming effect mediated by root exudates; (3) the microbial regulation mechanisms of carbon and nitrogen cycles mediated by root exudates; (4) the intra and inter-specific interactions mediated by root exudates.

Seagrass exhibits high levels of primary productivity in nearshore waters, and its growth is regulated by temperature. Under the background of global climate change, temperature stress has emerged as a significant factor affecting seagrass growth. Adaptation to global warming determines whether seagrass can fulfill its ecological services. We summarized the response and adaptation mechanisms of seagrass to global warming from the aspects of the physiological metabolism, distribution pattern, and gene expression. It was found that increasing temperatures changed the carbohydrate content in seagrass and inhibited its ability to absorb and assimilate nitrogen. This subsequently led to a reduction in the total nitrogen content and the metabolites related to nitrogen cycling in seagrass, and ultimately threatening its survival. Moreover, increasing temperature also inhibited the PSII activity of the photosynthetic system. The average threshold of temperature for photosynthesis in temperate and tropical seagrass is 22.3 and 29.8 ℃, respectively. Warming also led to a decrease in the growth rate and biomass of seagrass. Temperate and tropical seagrass gradually migrated to higher latitudes under the warming scenarios. In response to the stress of warming, seagrass can maintain the important functions of the ecosystems by increasing heat dissipation, accumulating saturated fatty acids, and increasing the activity of antioxidant enzymes and the expression of heat shock proteins (HSP70, HSP90). Finally, we proposed future research priorities: (1) clarifying the effects of increased temperature on the pattern of carbon partitioning in seagrass; (2) identifying the molecular mechanism of seagrass photosynthesis in response to high temperature stress; (3) investigating the effects of global warming on the distribution of tropical seagrass; and (4) exploring the mechanisms of high temperature stress on antioxidant enzyme activity and gene expression. These studies are essential to fully understand the survival potential of seagrass under global climate change and provide a scientific basis for the protection of seagrass ecosystems.

The interaction between plants and reptiles is an important link that maintains ecosystem structure and function, covering a wide range of aspects such as habitat provisioning, microclimate regulation, food chain connectivity, and seed dispersal. In recent years, this relationship is undergoing profound changes due to dramatic land-use changes, including agricultural expansion, urbanization, and desertification. We systematically examined how land-use change affects plant community structure, habitat integrity, and resource accessibility, and consequently alters reptile distribution patterns, behavioral strategies, and interspecific interactions. It was found that changes in land use patterns can alter the dependence of reptiles on plant shelter and resources, and even disrupt or reshape certain coexistence relationships. Although plant-reptile relationships are particularly important in arid and semi-arid ecosystems, current research still suffers from narrow scales, insufficient exploration of mechanisms, and lagging technical tools. We emphasize the need to explore the spatial and temporal variability of plant-reptile relationships in the context of land use by combining multiscale surveys and new ecological monitoring techniques to provide a scientific basis for ecosystem management and biodiversity conservation.

Southeast Asia harbors one of the world’s richest stocks of aboveground biomass. However, the recurrence of biomass burning in this region not only degrades habitat quality but also accelerates global climate change. Analyzing the spatiotemporal patterns of carbon emissions from biomass burning in Southeast Asia can help improve regional habitat quality and enhance resilience to global climate change. In this study, we integrated observational data on aboveground biomass carbon density in Southeast Asia with multisource remote sensing information and applied a random forest algorithm to model and reconstruct annual gridded aboveground biomass data for 2001-2020. By combining vegetation-specific combustion efficiencies and emission factors, we calculated the spatiotemporal distribution of biomass burning-induced carbon emissions in the region for each year over this 20year period. The results show that biomass burning in Southeast Asia is the most frequent in the winter and spring, and that the total burned area has been slowly declining over time. Over the past two decades, biomass burning carbon emission peaked at 0.15 Pg C in 2004 and reached a lowest value of 0.04 Pg C in 2001, which exhibited a slow downward trend. During the study period, the mean carbon emission from biomass burning was 801.55 g C·m^-2, showing a slightly increasing trend amid interannual fluctuations. Biomass burning activity also showed marked spatial heterogeneity, being concentrated mainly in the central and northern Indochinese Peninsula, the south-central region of Kalimantan (Borneo), and the southeastern Indochinese Peninsula. In the first two regions, most fires were forest fires, whereas in the latter region they were predominantly agricultural waste burning caused by traditional farming practices. These findings provide a scientific basis for developing fire management strategies and carbon emission reduction measures in Southeast Asia.

Fagus hayatae Palib. is a rare and endemic tree species in China. It is classified as a national secondgrade key protected wild species of China, and is the only species of genus Fagus that has been intermittently distributed from the subtropical mountains of mainland to Taiwan Island of China. In this study, we constructed a Biomod2 ensemble model to predict the potential suitable distribution area of F. hayatae and the environmental factors that limit its distribution, providing theoretical support for formulating effective protection measures. Based on the geographic distribution data of 82 raw occurrence records of F. hayatae, the suitable distribution range, the main environmental variables affecting its distribution, the changes in suitable habitats and the centroid shift under future climate conditions were evaluated and analyzed with three types of data: climate, topography, and soil, and the Biomod2 ensemble model. The results showed that the evaluation scores of the individual models-Random Forest (RF), Generalized Additive Model (GAM) and Generalized Boosted Model (GBM)-in the Biomod2 ensemble model were all close to 1, indicating that the ensemble model reached an excellent standard. The monthly mean diurnal range (Bio2), isothermality (Bio3), and elevation (elev) were the main environmental factors affecting the suitable distribution of F. hayatae. The total suitable area of F. hayatae under the current climatic conditions was about 5.10×10⁵ km², and the highly suitable areas were mainly distributed in the southwest and Taiwan of China. The potential distribution area and the actual distribution area showed a high degree of coincidence. Under future climate conditions, the highly suitable distribution area of F. hayatae will be significantly reduced. Among them, the reduction will be the greatest under the SSP24.5 emission scenario from 2081 to 2100, and the centroid of the suitable distribution area will mostly shift towards higher latitudes. In the future climate, F. hayatae will be drastically reduced in Southwest China and grow stably in Taiwan of China. It is suggested that nature reserves should be established in advance in the drastically reduced areas in Southwest and Central China. The results can provide scientific basis for in situ conservation of this endangered species, and also offer a reference for the selection of ex-situ conservation sites.