To investigate the influence of urban environmental differences on the leaf-unfolding phenology of trees, we extracted the leaf unfolding information of nine tree species using remote sensing data and analyzed their relationships with temperature, precipitation, and nighttime light in a pure forest in Shanghai. The results showed that : ① there were significant differences in the average onset of the leaf-unfolding phenology among species, from 95th to 104th day of the year; contrastingly, intra-species variation in leaf-unfolding date was greater, ranging from 69th to 138th day of the year. ② Different species exhibited different leaf phenology in response to environmental factors. Triadica sebifera was the most sensitive to precipitation changes, Taxodium distichum var. imbricatum was sensitive to precipitation changes and urbanization, and Koelreuteria bipinnata was sensitive to precipitation and climate changes. Other species were not sensitive to any environmental changes. ③ For species sensitive to environmental changes, the leaf-unfolding date was 45 days earlier when the average precipitation increase from 48 mm to 64 mm, and delayed by three days for every 1°C increase in average temperature before the growing season. The study showed that urban forest construction can be reasonably configured according to the response characteristics of a species to the environment, so that plants can better adapt to the environment and fulfill their roles in the ecosystem.
In this study, a benthic macroinvertebrates survey was conducted in the western Qingpu District. The Benthic Index of Biotic Integrity (B-IBI) was used to assess the regional water ecological health. The relationship between B-IBI and water quality indicators, including related indices, was analyzed, and the applicability of B-IBI in lake-swamp areas was explored. The results showed that the water ecological health of the study area was good overall, the proportion of healthy and sub-healthy sample sites was 67.7%, and B-IBI indexes of the lake-swamp areas are better than those of rivers. The B-IBI index can effectively indicate organic pollution and eutrophication in water bodies. In addition, a significant correlation among the biological indices was found, despite the differences in evaluation results. We conclude that the B-IBI index has good applicability for the water ecology assessment of lake-swamp areas.
The balance between supply and demand of ecosystem services is essential for sustainable development, while differentiated partitioning is important for optimal resource allocation. Based on the carnegie-ames-stanford-approach (CASA), the water balance equation, and the revised universal soil loss equation (RUSLE), this study depicts the supply and demand of carbon fixation and water and soil conservation services and their relationship in the Yangtze River Delta integration demonstration zone from 2000 to 2020. Self-organizing map (SOM) K-means two-order clustering technology is used to identify ecosystem service clusters dividing the ecological management zone. Management strategies are then proposed. The results show that: ① The supply of carbon fixation services continued to decrease but the demand increased. Additionally, the supply and demand of water and soil conservation services showed an increasing trend, and supply was less than demand. ② The supply-demand ratio of carbon fixation and soil conservation services showed an upward trend, whereas the supply-demand ratio of water conservation services showed a downward trend. Significant spatial differences were observed in the supply-demand ratio of ecosystem services. ③ Cluster analysis divided the demonstration area into different types of ecological regulation zones. The urban clusters in Wujiang and Shengze town districts are mainly to improve the capacity of water conservation services. The urban cluster in Qingpu District is to promote the water conservation and carbon fixation services capacity. The pilot start-up area and urban cluster in Jiashan City have a small gap between supply and demand, which focus on comprehensive protection. This study can provide decision-making support for resource allocation, ecological compensation, and coordinated development of regional integration in the demonstration area.
The development of city-scale vegetation maps is helpful for vegetation management and conservation. Vegetation classification systems in China mainly consider natural vegetation and most classification systems operate at the national or provincial scale, making them unsuitable for city-scale classification. Until now, the lack of a classification system designed specifically for urban vegetation has limited the studies on urban vegetation. Based on the origin, disturbance, and function, our classification system divides urban vegetation into natural, secondary, and cultivated vegetations. Based on the function, cultivated vegetation is further divided into artificial forest land, landscape green land , and urban agricultural vegetations. Based on the Classification System of China’s Vegetation in 1980 and the three newly proposed preliminary guideline documents for classification of natural vegetation, we establish a new urban vegetation classification system. We applied the principles of this new urban system in Shanghai and other areas in China, to further refine the system and ensure it has both academic and practical values. This work provides the theoretical basis for compiling information about urban vegetation and provides technical support for the recognition, protection, construction, and management of urban vegetation.
In this study, we obtained tree species from 72 Taoist temples across China. We subsequently documented the tree species composition, distribution pattern, and impact factors in different regions to determine the role of Taoist temples in biodiversity protection. The results showed that: ① Among 72 Taoist temples sampled across China, we observed a total of 354 species of trees, belonging to 85 families and 208 genera; ② The tree species in the Taoist temples were mainly native species, and the mean value for the proportion of native species in each Taoist temple was 62.5%±19.8% (mean ± standard deviation). Most of the Taoist temples (77.8%), moreover, housed threatened tree species; ③ Taoist tree species originated largely from subtropical regions, with the Yangtze River Basin being the most represented, especially in the southwest and south-central regions where a relatively large proportion of ethnic minorities reside; ④ The main factors affecting the distribution of Taoist tree species were geography and climate, but their composition was indistinguishable within each climate zone. As the climatic zone moves northward, there is no religious tree species replacement phenomenon (i.e., replacing the original religious tree species by native tree species with similar morphology or cultural meaning). The above results indicate that Taoist temples are rich in plant resources, which are potential biodiversity treasures. Thus, they play an essential role in protecting and maintaining biodiversity, with the potential to serve as a reference for regional ecological restoration and urban green space construction.
We collected soil samples from Maogang Town (Songjiang District, Shanghai) and used high-throughput sequencing techniques to reveal the diversity and community composition of soil bacteria and soil fungi in this peri-urban area. We found a total of 632 bacteria OTUs (operational taxonomic units) and 593 fungi OTUs in Maogang, in which the dominant microbial groups were Proteobacteria (bacteria) and Ascomycota (fungi). The Shannon Wiener index of soil bacteria was found to be in the range of 4.41 to 4.71, and the soil fungi’s Shannon Wiener index was found to be in the range of 1.99 to 2.60. Land-use type insignificantly affected α diversity of soil bacteria and soil fungi; however, land-use type significantly affected β diversity of soil bacteria (R = 0.32, p = 0.001) and soil fungi (R = 0.22, p = 0.001). Lastly, there were significant correlations observed between three soil environmental factors—namely, soil pH, porosity, and moisture—and community composition and β diversity of soil bacteria and soil fungi.
In this study, the effects of floating-bed planting on the retention characteristics of heavy metals by emergent hydrophytes in Jinze of Shanghai was studied. A series of sampling sites were set up in the reservoir at the bankside and the floating bed area, respectively.Cyperus alternifolius, Canna indica, andIris tectorum were selected as the representative emergent hydrophyte species to analyze the effects of floating-bed planting on the retention of Cu, Zn, Fe, Cr, Cd, and Pb in plants. The results showed that the biomass of C. indica and I. tectorum that were planted on the floating bed was significantly higher than those planted on the bankside (p < 0.05), while the biomass of C. alternifolius planted on the floating bed was significantly lower than those that were planted on the bankside (p < 0.05). The Cu, Fe, and Pb contents of C. indica planted on the floating bed, moreover, were significantly higher than those that were planted on the bankside (p < 0.05). The Cu, Zn, and Cd contents of C. alternifolius and I. tectorum planted on the floating bed were significantly higher than those that were planted on the bankside (p < 0.05). The retention of Cu, Fe, Cd, and Pb by C. indica; Cu, Zn, Fe, Cd, and Pb by I. tectorum; and Cd by C. alternifolius planted on the floating bed was significantly higher than those that were planted on the bankside (p < 0.05). In summary, correlations between the retention of different heavy metals for the same hydrophyte varied under different planting conditions; these differences were also observed among different species. Above all, it was shown that floating-bed planting can improve the growth and heavy metal absorption capacity of emergent hydrophytes to a certain extent, which has an important effect on the corresponding retention characteristic of heavy metals. Based on the results of our research, it is recommended that C. indica and I. tectorum would be preferred as floating bed plants. For the purpose of long-term monitoring, further systematic and comprehensive studies should be carried out in the future.
In this study, sedimentary component analysis and radioactive dating of sediment core from Krossfjorden were used to evaluate the vertical distribution of grain sizes and sedimentary changes since the 1930s. The analysis helps us to understand the environmental changes that have taken place in fjords of the high-latitude glacier front over the past few decades. The results show that the sedimentation rate (0.35 cm/a) has increased significantly since the 1990s and is about twice the rate observed historically before the 1990s (0.16 cm/a). After the 1990s, the mean and median grain size increased and sediment coarsening appeared. Moreover, the composition of grain sizes changed significantly, including a decrease in the sorting coefficient, increase in kurtosis fluctuation, and positive skewness change. Changes in the sedimentary characteristics indicate that the environment has changed in the Krossfjorden during the last thirty years. Climate change has caused rapid glacier melting, which has significantly increased the proliferation of terrigenous materials in fjords of the high-latitude glacier front.
Based on a field investigation of eleven villages in Shanghai across four seasons and statistical analysis of photos and observation data, 62 perennial herbs species, belonging to 30 families and 52 genera, were identified. Gramineae, Compositae, and Asparagaceae accounted for the majority of species observed; meanwhile, native plants accounted for a relatively low proportion, representing only 15.63% of the total. Challenges for the plant landscape include monotonous dominant species, similar landscapes, and poor growth conditions. Cluster analysis was used to classify the characteristics of the investigated perennial herbs and to select potential substitutes for underperforming species. The data can be used to optimize the allocation of plant communities and to provide a theoretical basis for improving the rural plant landscape of Shanghai.
This study investigated the combined application of water-retaining agents and organic fertilizers to enhance the soil water-holding capacity of waste dumps in open pit coal mines by measuring the anti-evaporation capacity and water content of man-made soil. The results showed that the anti-evaporation capacity of water-retaining agents in the gel state was superior to that in the dry state. Among the tested water-retaining agents, we found that France Essen at a concentration of 5% was the optimal choice. The soil water-holding time could be prolonged by the combined application of water-retaining agents and organic fertilizers, resulting in improved soil water-holding capacity. The optimum ratio of water-retaining agents to organic fertilizer was 3‰∶20% or 5‰∶10%. The water retention time of field capacity in this area would be improved by more than one time. Our findings provide valuable insights for the scientific community regarding soil remediation in waste dumps within open pit coal mines in Northwest China.
Exploring the remediation effect of native plants on soil contaminated with heavy metals has significant value for real-world applications. In this study, two native plants—reed and metasequoia—were selected for remediation of heavy metal arsenic in the soil of a woodland in Shanghai, and changes in soil indexes before and after phytoremediation were monitored. The results showed that: ① The arsenic content in rhizosphere soil of Ph. australis and Metasequoia was 52.4% and 28.6% lower, respectively, than the arsenic content in non-rhizosphere soil. The arsenic content in non-rhizosphere soil, moreover, was lower than the screening value for soil environmental risk. ② After comparing the microecological characteristics of rhizosphere between reed and metasequoia, it was found that metasequoia had a better nutrient enrichment effect than reed, demonstrating that metasequoia would have a better restoration effect in terms of soil fertility.
In this study, we analyzed the diversity of microbes across 45 collected soil samples using meta-barcoding. The analysis showed similar α diversity of soil microbes in a vertical forest (VF) building and the surrounding green area, but a high level of differentiation in the microbe community composition and β diversity between these two types of habitats. The results indicated that a VF can accommodate a large number of microbe species and provided evidence for the contribution of VFs to the conservation of urban biodiversity.
Based on the classical theory of island biogeography, thirteen remnant forest patches of fragmented urban habitats were chosen as islands, and the Lao Mountain as the mainland. Then, canonical correspondence analysis (CCA) was used to analyze the relationship between species composition and four factors — namely, patch area, distance to species pool, human disturbance intensity, and isolation degree. The lengths of vectors in CCA biplots were used as weights for each influencing factor to calculate the overall sum, named the isolated island index (III); an isolated island index evaluation system of forest patches in fragmented urban habitats was subsequently designed. The results indicated that the relationship between III and richness was significantly negative for native species, but not significant for alien species richness. There was a significant relationship found for bird dispersal and wind dispersal species. The linear function was determined to be the best simulating model.
In this study, an ecological survey of the lake water in Luxun Park from January to October 2019 was conducted to determine the community structure characteristics and health of phytoplankton in the water. In particular, the community composition, density, biomass, diversity, uniformity, and dominant species of phytoplankton were analyzed. A total of 83 genera of 8 phyla of phytoplankton were identified; of these, Cyanophyta, Chlorophyta, and Diatoms had the largest number of species. The annual average cell density was 14.17×106 ind/L, and the annual average biomass was 3.57 mg/L. Density and biomass typically increase with seasonal changes. The dominant phyla were the Cyanophyta, Chlorophyta, and Diatom phylum; meanwhile, Pseudo-Anabaena, Platychophyta, Scenedesmus, and Cyclotella were the major dominant species. Redundant analysis was used to further analyze the environmental factors in the lake water of Luxun Park. The results showed that pH, nitrate nitrogen, nitrous nitrogen, and permanganate index are the key factors affecting the structure of the phytoplankton community.
Using a combination of mechanical and representative sampling, plots in 13 cities of the Yangtze River Delta Region were surveyed in 2015—2016; the survey consisted of 449 plots across 76 urban parks, roads, and waterfront greenbelt areas. As part of this study, we analyzed the factors and drivers for species composition, distribution, size, coverage, and growth vigor of the predominant trees located in the urban plots; the data provides a scientific basis for the future construction of forest cities and the improvement of urban human settlements. The results show that: ① In total, 157 tree species were recorded in the surveyed plots, which belonged to 115 genera and 54 families. The dominant families belonged to the Rosaceae group (20 species across 12 genera), with a high proportion of single families and relatively dispersed species composition. ② The plots were characterized by significant temperate features (73 genera), showing that the tree species have typical temperate properties in application. ③ The main tree species of the urban man-made forests were Cinnamomum camphora and Platanus × acerifolia, with coverage reaching 27.45%; specifically, Cinnamomum camphora was the dominant species. The utilization of trees across different types of urban plots varied considerably. ④ It was found that tree species with 10 cm ≤ D≤ 30 cm constituted the majority of tall trees in the urban plots, including many species of native trees such as Sapindus saponaria, Koelreuteria bipinnata 'Integrifoliola', and Liquidambar formosana. The quantity and distribution of the trees, however, was found to be extremely unbalanced. The coverage of Cinnamomum camphora and Platanus × acerifolia in the area was as high as 45.18%, and the relative species diversity and community stability were found to be weak. We recommend that the coverage of other tree species is gradually increased in the future construction of urban plots.
Based on daily monitoring data of the Qingcaosha Reservoir water intake from 2010 to 2019, this paper analyzes the interannual and seasonal variation trends in the main physical and chemical water quality indicators, and explores the correlation between these indicators. The results show that: ① The dissolved oxygen at the intake of Qingcaosha Reservoir was consistently high, and the pH value was slightly alkaline. ② The concentration of ammonia nitrogen was low at the intake of Qingcaosha Reservoir, the concentration of nitrate-nitrogen was between 1.2 and 2.0 mg/L, the concentration of total phosphorus was between 0.1 and 0.2 mg/L, and the permanganate index was between 2.0 and 4.0 mg/L. These indexes, furthermore, all showed a downward trend after 2015, suggesting that the quality of incoming water subsequently improved. ③ Dissolved oxygen concentration, water temperature, and pH exhibited obvious seasonal variations, while total hardness, permanent hardness, conductivity, and chloride showed consistent variations under the influence of seawater intrusion. There was no significant seasonal variation in the other indicators. ④ The concentration of total phosphorus and the permanganate index increased with turbidity. The concentration of total phosphorus and nitrate nitrogen, moreover, decreased with an increase in water discharge at Datong.
In this study, follow-up monitoring over the course of two and a half years was carried out to analyze the long-term impact of sediment dredging on water quality, new sediments, benthos, and microorganisms of a river reach in Shandong Province. The results showed that the contents of CODCr and TP could be effectively removed by dredging, but little effect was observed on the contents of TN and NH4+-N. The C/N ratio in the new sediments decreased gradually over the observation period, which was beneficial to the recovery of microbial and benthic communities. Dredging can reduce the average biomass and density of tremididae in surface sediments to a certain extent, while Chironomidae density is less affected by dredging. Dredging did not change the microbial community structure significantly, which may be related to the depth of dredging. Exogenous pollutants and man-made drainage can affect the water quality and sediment pollutant content of the dredged river section; this effect, however, may recover in a short time after completion of the microbial community construction. In conclusion, the overall engineering effects of dredging were observed during the study period (2–4 years after dredging); in this time, the water quality and sediment pollution improved, which was conducive to the restoration of benthos and microbial diversity. However, with the passage of time and human interference, the net effect on water quality maintenance weakened.
In the Chongming Dongtan reclamation area, the soil carbon flux observation system (LI-8100A) and root removal method were used to continuously measure soil respiration (RS), heterotrophic respiration (RH), and autotrophic respiration (RA) of five land use types (Phragmites australis wetland, Imperata cylindrica wetland, young forest, middle-age forest, and cropland); the methods were also used to measure the soil temperature, volumetric water content, electrical conductivity, and other environmental factors in the 0-10 cm soil layer. In this study, the differences in soil respiration and its components among different land use types in the Chongming Dongtan reclamation area were systematically compared. The results showed that: ① RS in the young forest, middle-age forest, and cropland plot were significantly lower than those in the P. australis wetland and the I. cylindrica wetland plot; ② the proportion of RH found in the young forest, middle-age forest, and cropland was significantly higher than that observed in the P. australis wetland and the I. cylindrica wetland; ③ RS and its components showed a significant exponential relationship with soil temperature, but showed weak correlations with the soil volumetric water content and electrical conductivity. Compared with the residual wetlands, the different agroforestry utilization methods significantly reduced RS, but significantly increased RH, which may suggest that the soil organic carbon pool is still in a state of net loss after 20 years of reclamation. Thus, effective measures should be taken to improve the carbon sequestration capacity of the reclaimed soil in this area.
Density gradient centrifugation in combination with quantitative protargol stain (Ludox–QPS) is an important research method for the separation, extraction, and staining of microbenthos. Glutaraldehyde solution is the most widely used fixative for this method; however, it is a hazardous chemical and transportation by civil aviation is forbidden. Hence, biogeography studies using glutaraldehyde solution on a large scale are greatly limited. In contrast, samples fixed with formaldehyde solution can be transported by air consignment under certain conditions. To test whether the results of a study on microbenthic communities fixed with formaldehyde and glutaraldehyde are comparable, we collected microbenthic samples from three natural habitats (bare mudflat, Scirpus mariqueter meadow, sandy beach) and fixed them with either formaldehyde (final concentration is 1%) or glutaraldehyde (final concentration is 2%). Then, we tested the significance of differences in species composition, diversity, and biomass of the communities using an ANOSIM two-way crossed analysis (fixative type and habitat type). The results of this study demonstrate that although significant differences exist in the community structures among the three habitats, the species composition, diversity indices (number of species, number of individuals, evenness, Shannon-Wiener diversity index), and biomass of the microbenthic communities between the two fixative types have no significant differences. NMDS analysis also shows similar results (stress = 0.11). In conclusion, the data indicates that the microbenthic communities fixed by the two fixatives are comparable. Therefore, formaldehyde is also suitable for ecological research of microbenthos as a fixative.
In this paper, we explore the dynamic changes in photosynthesis and chlorophyll fluorescence in Kandelia candel leaves from restored mangroves in southern Zhejiang Province to provide a scientific basis for the ecological restoration and northward migration of Kandelia candel. Using a LI-6800F portable, automatic photosynthesis-fluorescence measurement system, the diurnal variation of photosynthesis and chlorophyll fluorescence of Kandelia candel were measured for one day each month in 2019; the data was then used to analyze the relationship between the two parameters. The results showed that, except for water use efficiency (WUE) and non-photochemical quenching (NPQ), the diurnal variation curves of the parameters were generally u-shaped or inverted u-shaped; examples of these parameters included transpiration rate (E), stomatal conductance (Gsw), electron transfer rate (ETR), and maximum photochemical reaction quantum efficiency ( $F_{\rm {v}}' $ / $F_{\rm {m}}'$ ). Some parameters, such as net photosynthetic rate (A), E, Gsw, and ETR, were found to be significantly higher in July and August than in November and December. In addition, except for WUE, the correlation between photosynthetic factors and fluorescence factors was significant on a daily basis, and the correlation between A, E, Gsw, WUE, and ETR was significant on a monthly basis. The results also demonstrated that the photosynthetic capacity of Kandelia candel leaves was the strongest around noon on any given day; at the monthly level, the strongest capacity was observed in the summer, followed by spring and autumn, and lastly winter. The correlation between photosynthesis and chlorophyll fluorescence of Kandelia candel leaves on individual days was higher than that at the monthly level.
中国综合性科技类核心期刊(北大核心)
