Table of Content

15 October 2023, Volume 34 Issue 10

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Short-term nitrogen deposition changes chemical composition of litter and soil organic matter in a Moso bamboo forest

WANG Yihuan, JIN Yidan, JIANG Mingkai, MA Shuqin, CHEN Youchao, CAI Yanjiang

2023, 34(10):  2593-2600.  doi:10.13287/j.1001-9332.202310.008

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To investigate the effects of short-term nitrogen (N) deposition on organic matter composition of litter and soil in Moso bamboo (Phyllostachys edulis) forests, we established a N-addition treatments (50 kg N·hm^-2·a^-1) to simulate the ambient and N deposition in a subtropical Moso bamboo forest from July 2020 to January 2022. We analyzed the organic matter composition of Moso bamboo leaf/root litter and soil by using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) technique. The results showed that short-term N deposition significantly increased the relative content of soil phenols by 50.9%, while significantly decreased fatty acids by 26.3%. The rela-tive content of alkanes & alkenes and lignin in leaf litter was significantly increased by 51.9% and 33.5%, respectively, while that of phenols and polysaccharides significantly decreased by 52.2% and 56.3%. In root litter, eleva-ted N significantly decreased the relative content of polycyclic aromatic hydrocarbons by 16.6%. Moreover, the relative content of fatty acids in soil organic matter was significantly positively correlated with the relative content of poly-saccharides in leaf litter. The relative content of phenols in soil organic matter was significantly positively correlated with the relative content of lignin, and negatively correlated with the relative content of polysaccharides in leaf litter. Our results demonstrated that short-term N deposition did not change the concentration of total organic carbon, total nitrogen, and C/N of the soil, leaf litter, and root litter, but significantly altered the chemical composition of organic matter. In addition, the changes in chemical composition of organic matter in soil under short-term N deposition were affected by the composition of organic matter in leaf litter.

Effects of nitrogen addition on acidolyzable organic nitrogen components and nitrogen mineralization in aggregates of Pinus massoniana plantations in the Three Gorges Reservoir area, China

CHEN Tian, CHENG Ruimei, SHEN Yafei, XIAO Wenfa, WANG Lijun, SUN Pengfei, ZHANG Meng, LI Jing

2023, 34(10):  2601-2609.  doi:10.13287/j.1001-9332.202310.004

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We sieved soils from a Pinus massoniana plantation in the Three Gorges Reservoir area into four aggregate sizes, including aggregates of 2000-8000 μm (large macroaggregates), 1000-2000 μm (coarse aggregates), 250-1000 μm (small macroaggregates), and <250 μm (microaggregates). We analyzed the differences in the acidolyzable organic N components and net N mineralization of the aggregates under different N addition levels (30, 60, and 90 kg N·hm^-2·a^-1, representing by N₃₀, N₆₀ and N₉₀, respectively). The results showed that net nitrification rate of the aggregates ranged from 0.30-3.42 mg N·kg^-1 and accounted for more than 80% of net nitrogen mineralization. Compared with the control, addition of 30, 60, and 90 kg N·hm^-2·a^-1 increased total N by 24.1%-45.5%, 6.4%-34.3%, and 7.9%-42.4% in the large aggregates, coarse aggregate, small macroaggregates, and microaggregates, increased net N mineralization rate by 1.3-7.2, 1.4-6.6, and 1.8-12.9 times, but decreased the contents of available phosphorus by 9.3%-36.9%, 12.2%-56.7%, and 19.2%-61.9%, respectively. The contents of total acidolyzable N, soil organic matter, and rates of net ammonification, net nitrification, and net N mineralization increased as the aggregate size decreased, while available phosphorus contents showed an opposite trend. The levels of acid-hydrolyzable N components were ranked as acidolyzable amino acid N > acidolyzable ammonia N > acidolyzable unknown N> acidolyzable amino sugar N. Total N was the dominant contributor to the increases in acid-hydrolyzable N components. Results of stepwise multiple regression analyses showed that acidoly-zable amino acid N and acidolyzable amino sugar N were predictors of net ammonification rate. Acidolyzable amino sugar N, acidolyzable amino acid N, and acidolyzable ammonia N were predictors of net nitrification, net nitrogen mineralization rate, and net nitrogen mineralization accumulation. The physical structure of aggregates was associa-ted with soil net N mineralization. Addition of N increased the contents and bioavailability of acidolyzable organic N, a large amount of which contributed to soil organic matter levels and the decrease in available phosphorus.

Responses of tree growth and intrinsic water-use efficiency of Robinia pseudoacacia to climate factors

HU Xiaochuang, GAO Wanting, SUN Shoujia, ZHANG Jinsong, MENG Ping, CAI Jinfeng

2023, 34(10):  2610-2618.  doi:10.13287/j.1001-9332.202310.011

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We investigated tree growth in Robinia pseudoacacia plantations at Ansai in Shaanxi Province and at Ji-xian in Shanxi Province by comparing the tree-ring width, basal area increase (BAI), δ¹³C value, intrinsic water-use efficiency (iWUE), and stomatal regulation. We quantified the responses of tree growth and iWUE to climatic factors at each site. The tree-ring width at Ansai and Jixian decreased with stand age, whereas the BAI at Ansai increased, and that at Jixian decreased after the BAI peaked. The δ¹³C value and iWUE of trees at Jixian were higher than those at Ansai. The iWUE of trees at both sites was similar to the constant intercellular CO₂ concentration/atmospheric CO₂ concentration (C_i/C_a) scenario, indicating that the C_i of trees was elevated with increasing C_a, while the stomata remained open. The BAI at Ansai was significantly positively correlated with highest temperature in May, relative humidity in June, precipitation in August, relative humidity in September, and standardized precipitation evapotranspiration index (SPEI) in September and October of current year, but negatively correlated with temperature in June. The BAI at Jixian was significantly positively correlated with SPEI in June and July, and lowest temperature in October of current year. The iWUE of trees at Ansai was significantly positively correlated with relative humidity and precipitation in June of the current year, but negatively correlated with minimum temperature in May, relative humidity in June, and temperature and maximum temperature in July of current year. A significant positive correlation between iWUE of trees at Jixian and lowest temperature in June of current year was detected. At the annual scale, the BAI of trees at Ansai was positively correlated with precipitation and SPEI, but no significant relationship was observed for trees at Jixian. However, the iWUE of trees at both sites was significantly affected by precipitation. Path analysis showed that SPEI and minimum temperature had a direct effect on BAI and iWUE of trees at Ansai, whereas precipitation and average temperature indirectly affected BAI and iWUE through SPEI. The highest temperature had a direct effect on tree growth at Jixian, whereas precipitation, minimum temperature, and average temperature had direct effects on iWUE. These results suggested that SPEI was the main climatic factor that affected the growth of R. pseudoacacia, while C_i was an important physiological factor. Our results could provide reference for the protection and management of R. pseudoacacia plantations under climate change.

Differences and mechanisms on water use of Pinus sylvestris var mongolica forests with different origins

LIU Chunying, DANG Hongzhong, CHEN Shuai, LI Mingyang, GE Jinnan, QIAO Yina, LIU Yuguo

2023, 34(10):  2619-2628.  doi:10.13287/j.1001-9332.202310.027

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Determining the differences of water use characteristics of a tree species with different origins (natural forests and introduced plantations) is significantly important for forest sustainable management. Pinus sylvestris var. mongolica is an important tree species of afforestation in the ‘Three North’ project in China. In this study, with Pinus sylvestris var. mongolica from two origins, we monitored the sap flow velocity of sapwood (J_s) of trees by thermal dissipation sap flow probes, and analyzed the relationship between water transportation and the environmental factors during the growing season. The results showed that under the typical sunny day, daily sap flow velocity (J_s-daily) of trees from plantations was significantly higher than that from natural forests. The mean value of J_s-daily was 132.98 and 114.86 cm·d^-1 for the two origins, respectively. Trees from plantations showed higher water transportation potential than natural forests. Vapor pressure deficit (VPD) mainly showed the driving effect on the water use process of trees from natural forests. In the plantations, there was an obvious threshold effect, and the inflection point of VPD was about 1.91 kPa, with the boundary function of J_s-hour increased to the maximum of 17.88 cm·h^-1. Atmospheric driven transpiration potential (J_s-hour/VPD) of P. sylvestris var. mongolica trees with two origins decreased with the aggravation of soil drought, but sensitivity to drought was higher in the plantations than in the natural forests, suggesting the strong ability of Pinus sylvestris var. mongolica to regulate water use process.

Responses of radial growth of Larix principis-rupprechtii to abrupt warming

WANG Heng, WANG Xiao-xue, JIA Jianheng, ZHANG Zihang, GUO Mingming

2023, 34(10):  2629-2636.  doi:10.13287/j.1001-9332.202310.006

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To investigate the impacts of abrupt warming on tree growth, we collected tree ring cores from larch (Larix principis-rupprechtii) in three different sites, including Saihanba National Nature Reserve, Pangquangou National Nature Reserve, and Fengning Qiansongba National Forest Park. Based on the tree ring method, Mann-Kendall test was used to examine the occurrence time of temperature rise mutation. We further analyzed the radial growth law of larch before and after the temperature mutation and its correlation with the monthly climate data. The results showed that the sudden temperature rise occurred in the Saihanba area in 1987, the Fengning area in 1989, and the Pangquangou area 1994. Before the sudden warming, there was no significant trend for the radial growth in all the three regions. After the sudden warming, however, it decreased significantly (with a decrease rate of 0.08·10 a^-1) in Saihanba area. The radial growth of larch increased significantly in Pangquangou area (with an increase rate of 0.10·10 a^-1), while no significant change was observed in the Fengning area. Before the sudden warming, there was a significant positive correlation between the radial growth of larch in the Saihanba area and the highest temperature in May and June. After the sudden warming, there was a significant positive correlation with precipita-tion in July, and a highly significant positive correlation with the standardized precipitation evapotranspiration index(SPEI) from September of the previous year to July. Prior to the sudden warming, there was no significant relationship between the radial growth of larch in the Pangquangou area and monthly climate factors. However, after the sudden warming, a significant positive correlation was found with the lowest temperature in September of the pre-vious year. Before the sudden warming, the radial growth of larch in Fengning area was significantly negatively correlated with the lowest average temperature in July. After the sudden warming, it showed a significant negative correlation with the average and highest temperatures in June. Accordingly, the radial growth of larch in the Saihanba area experienced drought stress following a sudden temperature change. If temperature continues to rise in the future, larch in the Fengning area would also face drought stress. Conversely, warming conditions would be beneficial for the radial growth of larch in the Pangquangou area.

Stem and leaf photosynthesis of seven desert woody species and its influencing factors

LI Minqing, ZHOU Le, WANG Xiyong, KANG Xiaoshan, LI Congjuan, LIU Ran

2023, 34(10):  2637-2643.  doi:10.13287/j.1001-9332.202310.007

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Stem photosynthesis widely presents in desert plants, which increases carbon uptake capacity. In this study, we measured the photosynthetic characteristics of leaves and stems in seven desert woody plants (Populus euphratica, Populus alba var. pyramidalis, Populus pruinose, Haloxylon ammodendron, Calligonum rubicundum, Calligonum caput-medusae, Ammopiptanthus mongolicus) in the same habitat, using a portable Li-6400XT photosynthesis system combined with P-Chamber. We analyzed stem photosynthetic rate and its relationship with leaf photosynthetic rate. We measured the stem functional traits, including water content, stem dry matter content, chlorophyll content, water potential, non-structure carbohydrate (NSC), etc., to find out the main affecting factors of stem photosynthesis. The results showed that stem photosynthetic rate of seven species ranged from 0.72 to 1.71 μmol·m^-2·s^-1, with the largest of P. pruinose and the smallest of H. ammodendron. Stem photosynthetic rate could offset CO₂ of stem respiration by 57%-83%. Leaf photosynthetic rate of the seven sepceis ranged from 12.80 to 22.54 μmol·m^-2·s^-1, with H. ammodendron and A. mongolicus being lower than those of the other five species. There was a significant positive correlation between leaf photosynthetic rate and stem photosynthetic rate. Stem water use efficiency was 2.2-7.7 times of the leaf. Chlorophyll content, NSC, stem respiration rate, and leaf photosynthetic rate were the main factors affecting stem photosynthesis.

Physiological response to drought stress and drought resistance of six Helleborus orientlis cultivars

ZHAO Lei, JIN Haidi, CAO Xiaoyun, DENG Wenhui, DU Lingjuan

2023, 34(10):  2644-2654.  doi:10.13287/j.1001-9332.202310.003

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We examined the responses of physiological and leaf anatomic structural characteristics of six Helleborus orientalis cultivars to different degrees of drought stress. A membership function was used to evaluate drought resis-tance and identify physiological and leaf anatomical indicators that exhibited a stronger correlation with drought tolerance. The results showed that leaf thickness, leaf area per unit mass and soluble protein levels of the six cultivars significantly decreased with the increases of drought stress. Net photosynthetic rate, stomatal conductance, and transpiration rate of leaves increased first and then decreased, while the intercellular CO₂ concentration decreased. The relative electrical conductivity, MDA, and H₂O₂ contents of leaves were increased. Soluble saccharide and proline contents, and antioxidant enzyme activities were first elevated and then decreased. With the increases of drought stress, the ratio of palisade tissue thickness to sponge tissue thickness and stomatal density increased. Key indicators and relativities in evaluating drought resistance of those cultivars were proline, soluble sugars, and the ratio of palisade tissue thickness to sponge tissue thickness. H. orientalis ‘Anemone Red’ and H. orientalis ‘Ane-mone Red spotted’ had better drought resistance, which could be the excellent parental materials for the cultivation of new drought-resistant cultivars in the future.

Photosynthetic characteristics of Leymus chinensis and Medicago sativa in artificial grassland

SHI Yiping, SONG Yantao, Namuhan, PENG Qingtian, LYU Linyou, SHEN Yue, Qian Na, Wu Yunna

2023, 34(10):  2655-2662.  doi:10.13287/j.1001-9332.202310.009

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To explore the effect of monoculture and mixture sowing artificial grassland on the photosynthetic characteristics of Leymus chinensis and Medicago sativa, we determined the diurnal variation of photosynthetic properties of L. chinensis and M. sativa under different treatments. The results showed that the diurnal changes of net photosynthetic rate, blade temperature and transpiration rate of L. chinensis and M. sativa showed ‘unimodal type’ in monoculture, the stomatal conductance of M. sativa showed ‘unimodal type’, and the stomatal conductance and water use efficiency of L. chinensis showed ‘bimodal type’. Under the mixed sowing treatment, the diurnal changes of net photosynthetic rate, blade temperature and transpiration rate of L. chinensis and M. sativa showed ‘unimodal type’, the stomatal conductance and water use efficiency of L. chinensis showed ‘unimodal type’, and the stomatal conductance of M. sativa showed ‘bimodal type’. The peak photosynthetic rate of L. chinensis under mixture was signi-ficantly higher than that under monoculture, being 17.72 and 13.65 μmol CO₂·m^-2·s^-1, respectively. Under monoculture and mixture sowing treatments, the chlorophyll content of L. chinensis was higher than that of M. sativa, nitrogen content of the leaves of L. chinensis was lower than that of M. sativa, and the nitrogen content in the leaves of mixture sowing L. chinensis was significantly higher than that of monoculture sowing L. chinensis, which were 27.60 and 22.55 g·kg^-1, respectively. Net photosynthetic rates of L. chinensis and M. sativa were significantly positively correlated with stomatal conductance and transpiration rate, and significantly negatively correlated with intercellular CO₂ concentration under different planting methods. Net photosynthetic rate of M. sativa was significantly positively correlated with blade temperature and water use efficiency. In summary, mixed sowing was beneficial to enhance nitrogen content of L. chinensis. Our results provided a theoretical basis for the response of the photosynthetic characteristics of forage to planting mode of artificial grassland.

Field practice of Scirpus mariqueter restoration in the bird habitats of Chongming Dongtan Wetland, China

ZHANG Qun, LI Bo

2023, 34(10):  2663-2671.  doi:10.13287/j.1001-9332.202310.029

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The coastal saltmarshes in China have been seriously degraded and artificial restoration strategies have become one of the primary measures to protect the coastal habitats. In this study, we investigated efficient restoration techniques for native saltmarsh plants in vacant habitats within the project area of the Ecological Control of Spartina alterniflora and Improvement of Birds Habitats in the Shanghai Chongming Dongtan Bird National Nature Reserve in the Yangtze Estuary. Through field and pilot experiments, we analyzed the effects of propagule types and transplanting methods on the restoration efficiency of Scirpus mariqueter, a dominant saltmarsh species in the Yangtze Estuary. We further evaluated the cost and efficiency of various restoration strategies. Our results indicated that: 1) The corm seedlings of S. mariqueter had higher flood tolerance, and were suitable for use in the habitats with higher environmental heterogeneity. 2) Across the four treatments for S. mariqueter restoration, the most economically efficient treatment was to transplant low-density corm seedlings without sediment, with an investment cost of approximately ￥10100 per hectare. The costs were ￥41100, ￥30000, and ￥120100 per hectare for high-density without sediment, low-density with sediment, and high-density with sediment restoration, respectively. 3) After nearly 5-yr efforts, the S. mariqueter community of Plot C3 in project area had achieved a coverage of over 60%, marking a relatively successful large-scale field restoration. This study could provide the foundation and support for large-scale coastal saltmarsh restoration projects.

Effects of maize and peanut co-ridge intercropping on crop photosynthetic characteristics and intercropping advantages

CHEN Junnan, JIANG Wenyang, ZAN Zhiman, WANG Jiangtao, ZHENG Bin, LIU Ling, LIU Juan, JIAO Nianyuan

2023, 34(10):  2672-2682.  doi:10.13287/j.1001-9332.202310.010

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To clarify the photosynthetic mechanism contributing to the enhancement of intercropping advantages through co-ridge intercropping of maize and peanut, we conducted a field randomized block experiment under two phosphorus levels of 0(P₀) and 180 kg P₂O₅·hm^-2(P₁₈₀) with flat intercropping of maize and peanut (FIC) as the control. We analyzed the effects of co-ridge intercropping of maize and peanut (RIC) and groove-ridge intercropping of maize and peanut (GIC) on crop leaf area index (LAI), SPAD values, CO₂ carboxylation ability, photosystems coordination (Φ_PSⅠ/PSⅡ), and intercropping advantage of yield. The results showed that RIC significantly increased SPAD value at the silking stage of intercropping maize, and significantly improved the apparent quantum yield of photosynthesis (AQY), maximum electron transfer rate (J_max), maximum rate of Rubisco carboxylation (V_c,max), net photosynthetic rate at the CO₂ saturation (A_max) and Φ_PSⅠ/PSⅡ of intercropping maize compared with those of FIC and GIC at silking stage and milking stage, but reduced the ratio of variable fluorescence F_k to amplitude F_j-F_o(W_k) and the ratio of variable fluorescence F_j to amplitude F_p-F_o(V_j) of the functional leaf photosystem Ⅱ (PSⅡ) at the milking stage of maize. There were no significant differences in these parameters between FIC and GIC. Compared with FIC, both RIC and GIC increased LAI of intercropping peanut at late growth stage and SPAD value at pod setting stage, significantly improved V_c,max, A_max, and Φ_PSⅠ/PSⅡ, and reduced W_k and V_j values of intercropping peanut functional leaves at pod expanding stage. The difference in these parameters between RIC and GIC were not significant. The land equivalent ratio and intercropping advantages of RIC were higher than those of FIC and GIC. Phosphorus application could further promote V_c,max, J_max, A_max and Φ_PSⅠ/PSⅡ of intercropping maize and peanut, and significantly improve yield advantages of intercropping. The findings indicated that co-ridge intercropping could enhance CO₂ carboxylation and fixation by improving photosynthetic electron transport and pho-tosystems coordination, improve the photosynthetic rate of functional leaves of maize and peanut, thus increase crop yield and intercropping advantages.

Temporal-spatial variations of root and soil nutrient under continuous intercropping of alfalfa and oat

WANG Xue, LIU Xiaojing, WANG Jing, TONG Changchun, WU Yong

2023, 34(10):  2683-2692.  doi:10.13287/j.1001-9332.202310.017

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We investigated root and soil nutrient characteristics in the monoculture and continuous alfalfa/oat intercropping in the high-yield years by using soil filling and frame planting method in the field, and analyzed the relationship between root systems and soil nutrients. The results showed that intercropping reduced root weight and total root length proportion of oat in the 0-10 cm soil layer compared with the monoculture. However, intercropping significantly increased root weight and root surface area of oat in the 20-30 cm soil layer, root length and root density of alfalfa in the 10-20 cm soil layer, and the contents of available phosphorus and organic matter of the alfalfa/oat intercropping system in the 0-40 cm soil layer. As the planting years increased, total root length, root weight, root surface area, and proportion of root weight and root length of alfalfa in the 0-20 cm soil layer gradually increased in the intercropping system, and the root weight, total root length, root surface area, and root average diameter of oat increased, especially the root weight and root surface area of oat in the 20-30 cm soil layer. Moreover, the content of available nutrients in all soil layers decreased subsequently. In the alfalfa/oat intercropping system, continuous intercropping could significantly increase total root length of alfalfa in the 10-20 cm soil layer, improve root weight and root surface area of oat in the 20-40 cm soil layer (especially in the 20-30 cm soil layer). With the increases of planting years, intercropping intensified the absorption and competition of available nutrients by the roots of alfalfa and oat in the 0-40 cm soil layer, thereby reduced the accumulation of available nutrients in the soil.

Short-term effect of different returning methods of maize straw on the temperature of black soil plough layer

LI Ruiping, LUO Yang, SUI Pengxiang, ZHENG Hongbing, MING Bo, LI Shaokun, WANG Hao, ZHENG Jinyu

2023, 34(10):  2693-2702.  doi:10.13287/j.1001-9332.202310.014

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Clarifying the effect of different maize straw returning methods on soil temperature is crucial for optimizing the management of farmland straw and the efficient utilization of heat resources in the black soil region of Northeast China. To investigate the impacts of straw returning methods on soil temperature, we conducted a field experiment with four treatments during 2018 and 2020, including plough tillage with straw returning (PTSR), rotary tillage with straw returning (RTSR), no-tillage with straw returning (NTSR), and a control treatment of conventional ridge tillage without straw returning (CT). We measured soil temperature and water content at the 5 cm, 15 cm and 30 cm soil layer, and the straw coverage rate during the 3-year maize growth period. We further analyzed the differences of soil temperature in different soil layer under different treatments, accumulated soil temperature and growing degree-days (GDD) above 10 ℃, daily dynamics of soil temperature, the production efficiency of air accumulated temperature among different treatments, and explored factors causing the difference of soil temperature and the production efficiency of air accumulated temperature. Our results showed that different treatments mainly affected soil temperature from the sowing to emergence stage (S-VE) of maize. The daily average soil temperature showed a trend of CT>PTSR>RTSR>NTSR. The differences of soil temperature under different treatments showed a decreasing trend as growth process advanced and soil depth increased. Compared with the CT treatment, soil temperature at 5 cm depth was decreased by 0.86, 1.84 and 3.50 ℃ for PTSR, RTSR, and NTSR treatments, respectively. NTSR significantly reduced the accumulated temperature of ≥10 ℃ in different soil layers and GDD. The accumulated temperature ≥ 10 ℃ at the 5, 15, and 30 cm soil layers decreased by 216.2, 222.7, and 165.1 ℃·d, and the GDD decreased by 201.9, 138.7 and 123.9 ℃·d, respectively. In addition, production efficiency of air accumulated temperature decreased by 9.7% to 15.6% for NTSR. Conclusively, PTSR and RTSR had significant impacts on topsoil temperature during the maize growing period from sowing to emergence, but did not affect the accumulated soil temperature and the production efficiency of air accumulated temperature. However, NTSR significantly reduced topsoil temperature and production efficiency of air accumulated temperature.

Impacts of upslope inflow and soil pipe collapse on slope water erosion in the typical Chinese Mollisol region

QIN Qishan, ZHENG Fenli, ZHAO Luyou, MO Shuaihao, WANG Lun, GENG Huajie

2023, 34(10):  2703-2712.  doi:10.13287/j.1001-9332.202310.016

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Understanding the effects of upslope runoff and soil pipe collapse on slope water erosion can provide scien-tific basis for preventing Mollisol degradation caused by soil erosion. We conducted an experiment to investigate the effects of upslope inflow rate and soil pipe collapse on slope water erosion and to quantify the contribution of soil pipe erosion to slope soil erosion. The experiment included three inflow rates (30, 40, and 50 L·min^-1) and three near-surface soil hydrological conditions (without soil pipe: NP; with soil pipe but no pipe flow: PF₀; with pipe flow: PF₁). The results showed that: 1) Slope soil erosion increased with increasing inflow rates; when the inflow rate increased from 30 L·min^-1 to 40 and 50 L·min^-1, slope soil erosion increased by 100.0%-111.5% and 214.8%-289.2%, respectively. 2) The soil pipe occurrence and pipe flow formation aggravated the slope water erosion process. At inflow rates of 30, 40, and 50 L·min^-1, slope soil loss under the PF₀ and PF₁ treatments were 1.4-1.6 times and 1.7-2.1 times of that under the NP treatment. The contribution of soil pipe erosion to slope soil loss was 26.7%-37.6% under the PF₀ treatment and 40.5%-51.9% under the PF₁ treatment. 3) Soil pipe collapse intensified the rill erosion process. Compared with the NP treatment at 30, 40, and 50 L·min^-1 inflow rate, rill erosion amounts under the PF₀ and PF₁ treatments increased by 38.1%-66.0% and by 93.7%-128.4%, respectively. Our results suggested that increasing upslope inflow rate resulted in higher surface runoff velocity, which promoted runoff detachment and transport capacity, and then aggrandized the amount of slope soil erosion. Moreover, soil pipe collapse exacerbated rill erosion process. When the soil pipe collapsed, all surface runoff was converted to soil pipe flow, which accelerated flow velocity and slope soil erosion process, and then increased the amount of slope soil erosion.

Spatial-temporal variations of vegetation coverage and its driving force in Inner Mongolia grassland, China

KUI Guoxian, SHI Changqing, YANG Jianying, LI Ruipeng, WEI Guangkuo, LIU Jiaqi

2023, 34(10):  2713-2722.  doi:10.13287/j.1001-9332.202310.005

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Inner Mongolia grassland is rich in natural vegetation and mineral resources. Based on Landsat5/7/8 NDVI data, we used pixel binary model to invert vegetation coverage of Inner Mongolia grassland area, investigated the stability, spatial distribution, and future evolution trend of vegetation coverage by using Sen+MK and Hurst index, and analyzed the driving factors of the spatial differentiation of vegetation coverage by the optimal parameters-based geographical detector. The results showed that vegetation coverage of Inner Mongolia grassland showed an increasing trend from 2006 to 2020, and the overall spatial pattern was high in the east and low in the west, mainly with great fluctuation. The regions with slight or obvious improvement characteristics (64.8%) were much more than those with slight or severe degradation characteristics (23.2%). Compared with that in the past 15 years, the proportion of degraded vegetation in the future is expected to increase to 36.6%. The central part of Xilin Gol League and Wulanqab in the central grassland area, the western part of Hulunbuir and Erdos in the eastern grassland area, and Wuhai in the western grassland area were at the risk of degradation, which should be paid more attention. Precipitation was the dominant factor of spatial differentiation in Inner Mongolia grassland, while soil type, land use, and air temperature had the most significant synergistic effect.

Response of vegetation to terrestrial water storage in Southwest China

WANG Xiyao, WEI Dengfeng, KUANG Honghai

2023, 34(10):  2723-2729.  doi:10.13287/j.1001-9332.202310.002

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To explore the responses of vegetation growth to change in terrestrial water storage in Southwest China, we analyzed the change trend and relationship between vegetation and terrestrial water storage anomaly (TWSA) in Southwest China from January 2003 to December 2021 by using TWSA data of Gravity Recovery and Climate Experi-ment (GRACE) satellite and normalized differential vegetation index (NDVI) data. The results showed that NDVI in Southwest China during the study period showed an overall upward trend. Meanwhile, TWSA showed a significant downward trend in central and southern Tibet, and a significant upward trend in northwest Tibet and southeast region of Southwest China. Results of Pearson correlation analysis showed that there were significant spatial differences in responses of NDVI to TWSA changes in Southwest China. NDVI had a significant negative response to TWSA changes in most regions of Tibet, but a significant positive response to TWSA changes in most regions of southeast region of Southwest China. Such differences were driven by climate change and topography.

Identification of key points and differentiation planning strategies of Shantou, Guangdong, China

JIAN Yuqing, DAI Yuxin, HUANG Zhibin, ZHAN Angshuo, LI Hecheng, WANG Zhifang

2023, 34(10):  2730-2738.  doi:10.13287/j.1001-9332.202310.024

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Territorial ecological restoration planning is a carrier process for carrying out territorial space regulation and ecological restoration. However, current urban planning efforts only focus on ecological processes, and fail to coordinate the development of both ecology and society. Taking Shantou, a city in Guangdong Province, as an example, we focused on the identification of ecological restoration nodes and the development of differentiated planning strategies from a comprehensive ecological-social perspective. By considering ecosystem integrity, we extracted the ecological corridors and key points by identifying ecological sources and constructing resistance surfaces, constructed an ecological recreation service evaluation system from the social perspective in terms of recreational allocation and recreational value to identify key areas for recreation services, and obtained different types of ecological restoration strategies by synthesizing the results of ecology and recreation. The results showed that there were 136 ecological corridors and 77 ecological nodes in Shantou, with a total length of 380.58 km. The most important recreation areas were the coastline, several inland bays, and wetland tidal flats, with an area of 33.78 km² and accounting for 1.6% of the total area. Low-level recreation areas was the largest, accounting for 57.3% of the total area. We proposed the composite strategy of “recreation expansion & fishery development”, the connectivity strategy of “ecological construction & corridor connection”, and the protection strategy of “vegetation restoration & development restriction”. This study would provide a comprehensive analysis path for the ecological protection and restoration planning of coastal cities, and would help promote the practicality and maximizing the comprehensive benefits of territorial ecological restoration planning.

Blind area and layout optimization of parks based on the spatial supply-demand evaluation in Taiyuan City, China

CHEN Xiaoping, DENG Yayu, HE Jinyu, HAN Meng, LIU Yanhong, WU Xiaogang, ZHEN Zhi-lei

2023, 34(10):  2739-2746.  doi:10.13287/j.1001-9332.202310.019

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It is of great practical significance to identify service blind area, scientifically select park construction areas, and clarify the priority of parks’ construction based on the co-ordination of supply-demand evaluation. With the urban parks within the Taiyuan Ring Expressway as the research subjects, we estimated the accessibility range and the service pressure of each park by using the application programming interface of Gaode map route planning and point of interest data to characterize their supply and demand levels. We identified the service blind areas of parks by overlay analysis, and used the location-allocation (LA) model to purposefully supply park green space. Results showed that the accessibility coverage rates of the parks by walking and bicycling within 15 minutes were 35.6% and 71.7%, respectively, indicating insufficient supply capacity of parks. The areas with large potential demand for park green space in Taiyuan were mainly concentrated in the business district of Qinxian-Changfeng Street and the Shuangta business district within Dongzhong ring road, which existed the obviously invisible blind areas. Finally, we proposed new park green space site selection proposal based on LA model. Optimization results indicated that the coverage rates of walking and bicycling within 15 minutes increased to 46.7% and 81.0%, respectively, and that the service pressure of parks was relieved. We combined the leisure demands of urban residents and the distribution of urban parks by utilizing network big data, which could promote the scientific nature and accuracy of the optimizing site selection and provide scientific method and theory basis for urban park construction.

Temporal and spatial evolution of ecosystem service value in Ili Valley and its driving factors

TAN Xu, WANG Chengwu

2023, 34(10):  2747-2756.  doi:10.13287/j.1001-9332.202310.021

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Ili Valley is an important ecological barrier in western China and an important economic zone of the Belt and Road Initiative. Exploring the driving factors of ecosystem service value (ESV) based on land use change is of great significance for optimizing regional ecological environment and coordinating human-land relationship. Based on three periods of land use data from 2000 to 2020 in Yili Valley, we used ArcGIS 10.8 and Origin to analyze the characteristics of land use change, temporal and spatial variations of ESV, and the synergy and trade-offs of ecosystem services, and explored the driving factors affecting the spatial differentiation of ESV and the interaction among factors by using Geo-Detector. The results showed that land use change in the study area was obvious from 2000 to 2020, with the area of grassland and water area being greatly reduced and the largest increase for the area of construction land. The ESV of grassland and water area and the service function of water resource supply decreased significantly. ESV high value areas were transformed to low value areas. Synergy was the dominant relationship among ecosystem services in the study area, which showed an increasing trend. Elevation was the main driving factor of ESV spatial differentiation in Yili Valley, and the low elevation plain area suitable for human activities on both sides of the basin was the low ESV value area. The interaction between all factors was manifested as enhanced relationship, while the explanatory power of natural factors was higher than that of social and economic factors.

Identification of ecological functional zoning and its influencing factors in the Sihu Lake Basin, China

WANG Binyu, WANG Ling, CHEN Junchen, QI Qi, HE Shuyu, YANG Ziqi, LI Zhaohua, LI Kun

2023, 34(10):  2757-2766.  doi:10.13287/j.1001-9332.202310.023

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Rational delineation of ecological functional areas and clarification of their driving factors are of significance for maintaining regional ecosystem stability. We assessed six ecosystem services of Sihu Lake Basin located in Jianghan Plain using InVEST and RUSLE models and recreational scoring methods. By using K-means clustering, we identified the ecosystem service bundles, and delineated the ecological functional areas in combination with ecological sensitivity and ecosystem service bundles. The dominant driving factors of different ecological functional areas were analyzed by Geodetector. The results showed that the spatial distributions of habitat quality and carbon sequestration services were similar, with high values being mainly concentrated in Changhu Lake Basin and Honghu Lake Basin. However, the spatial distributions of crop production and soil conservation services were different, with high-value areas concentrated in the northwest area with mountains. The high values of water production service were mainly concentrated in the eastern part of Honghu Lake Basin, while the high-value areas of ecological recreation service were mainly concentrated in the northwest area and the southern part of Honghu Lake Basin. The Sihu Lake Basin could be classified into crop production bundle, habitat quality bundle, and urban living bundle according to cluster analysis. The low ecological sensitivity areas accounted for 59.0% of the Sihu Lake Basin. We classified the study area into ecological restoration areas, ecological conservation areas, ecological transition areas, ecological development areas, and comprehensive use areas by combination of ecological sensitivity and ecosystem service bundles. The geodetector results indicated that the driving factors of each ecological function zone were significantly different. The natural factors significantly influenced the ecological restoration zone, while the normalized vegetation index and population density were the main influencing factors in the ecological conservation zone and the ecological development zone, respectively. Land use type was the main influencing factor in the ecological transition zone and the comprehensive use zone. The results could provide important support for coordinated regional social development and environmental protection.

Spatial and temporal variations of landscape ecological risk in the dry and hot valley of the Jinsha River during 2000-2020

ZHANG Junming, SUN Yongyu, ZHOU Shan, QIU Xinteng, SUN Shixian, OU Zhao-rong

2023, 34(10):  2767-2776.  doi:10.13287/j.1001-9332.202310.026

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Scientific assessment of landscape ecological risk in ecologically fragile areas of the upper reaches of the Yangtze River is of great significance to regional ecological regulation and construction of the Yangtze River ecological security barrier. With the dry-hot valley area of Jinsha River in Yunnan Province as the research area, we constructed a landscape ecological risk evaluation model, and analyzed the spatial and temporal variations of regional landscape ecological risk. The results showed that the average values of landscape ecological risk index (LER) in the study area were 0.414, 0.398, and 0.462 in 2000, 2010 and 2020, respectively. The LER value of the whole region had reached a higher risk level by 2020. In 2000 and 2010, the landscape ecological risk zones of each level were staggered, and the high-risk zones showed a centralized distribution in 2020. During the two decades, the average LER of each section in the study area was around 0.42, which was close to the high risk level, indicating high landscape ecological risk level. The area of middle and low risk zones had decreased, while the area of high risk zone had significantly increased. The area of high risk zone in the western and middle sections was much higher than that in the eastern section. The area with significant changes of landscape ecological risk accounted for about 55% of the total study area, with obvious spatial agglomeration characteristics of significant increase and decrease of risk. The competition between government-led ecological management policies and measures and market-led land use activities was the main cause of landscape ecological risk variations in this region. In the future, the driving mechanism of climate change coupled with human activities on global and local landscape ecological risk changes in the study area should be uncovered to effectively cope with regional ecological risks.

Simulation of land use and assessment of ecosystem service value in the eastern coastal cities of Zhejiang Province, China

TAN Zhaozhao, CHEN Yuqiu, DING Jingfeng, LIU Mengdi, WANG Hao, WANG Jiang

2023, 34(10):  2777-2787.  doi:10.13287/j.1001-9332.202310.025

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Simulating the change of ecosystem service values (ESV) caused by land use/cover change (LUCC) in the eastern coastal cities of Zhejiang Province is of great significance for regional sustainable development and ecological security. Based on remote sensing images of land use and Statistics Yearbook of 2000, 2010, and 2020, we analyzed the influence of LUCC on ESV in the study area during 2000-2020. We used the PLUS model to simulate land use change under three scenarios, including inertial development, ecological protection, and urban development in 2030, analyzed the spatial distribution and concentration degree of ESVs based on grid scale, and clarified the sensitivity characteristics of ESVs. The results showed that the construction land area showed an increasing trend during 2000-2020. The area of forest, cultivated land and water decreased significantly, resulting in a continuous downward trend of ESVs, which decreased by 160×10⁸ yuan. Under the simulation of three scenarios of inertial development, ecological development, and urban development, the construction land area would increase by 93624, 54927, and 111966 hm², respectively. The eastern plain would become the agglomeration area of construction land expansion. The ESVs of those three scenarios was 1693×10⁸, 1729×10⁸, and 1688×10⁸ yuan, respectively, which were all lower than the ESVs of the study area in 2020. The decline rate of ESV in the ecological protection scenario slowed down. The spatial distribution of ESVs in the study area was high in the west and low in the east. Hot spots and cold spots of ESVs were distributed in a large range with strong agglomeration. Hot spots were mainly concentrated in the west, while cold spots were mainly distributed in the east and north.

Improvement and application on the estimation model of windbreak and sand fixation function based on remote sensing soil moisture factor

MENG Jian, SUN Hao, TENG Chao, WANG Sihan, WANG Yuxin, WANG Chaoqun, WU Ruixiang

2023, 34(10):  2788-2796.  doi:10.13287/j.1001-9332.202310.022

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Soil moisture factor is one of the important parameters in the study of wind and sand fixation functions of ecosystems. Traditional methods often use potential evaporation, rainfall, and irrigation observed by meteorological stations to estimate soil moisture, which has significant limitations in terms of spatial continuity and data availability. Based on the development of remote sensing technology in soil moisture detection, we selected four remote sen-sing indicators for soil moisture (MODIS evapotranspiration ratio method, SMAP soil moisture ratio method, visible shortwave infrared drought index method, and remote sensing humidity index method) to improve the estimation of soil moisture factor in the modified wind erosion equation model (RWEQ), and used the improved algorithm to analyze the spatiotemporal variations and driving factors of wind prevention and sand fixation services in the northwest region of Liaoning Province from 2001 to 2021. The results showed that the MODIS evapotranspiration ratio method had the highest correlation with traditional meteorological methods in calculating soil moisture. The formula obtained by fitting the two could be used to improve the calculation of soil moisture factor in the RWEQ model. From 2001 to 2021, the wind prevention and sand fixation capacity in the northwest region of Liaoning Province showed strong spatial distribution characteristics in the northern and eastern regions, while weak in the central and western regions. According to Mann-Kendall trend testing, 72.7% of the regions in northwest Liaoning Province were showing an upward trend in their ability to prevent wind and fix sand. The application of geographic detector models for driving factor analysis showed that the change in wind and sand fixation capacity was a process of multiple factors interacting with each other, greatly influenced by soil type, annual wind speed, and economic development level. Moreover, the interaction between various driving factors had a higher impact on wind and sand fixation than that of single factors. The results could improve the RWEQ model estimation and provide technical support for the long-term analysis of ecological function formation mechanisms and driving forces in the northwest region of Liaoning.

Community structure of soil fauna under different tree species in subtropical forests

WEN Huihui, WU Fuzhong, ZHANG Huiling, PENG Qingqing, QIU Danni, PENG Yan

2023, 34(10):  2797-2804.  doi:10.13287/j.1001-9332.202310.031

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Soil fauna play an important role in key functions of ecosystem such as material cycling. Litter quality and microenvironment of different tree species may regulate soil fauna community structure. In this study, we investigated soil fauna community structure, the differences of taxonomic and functional groups, and the regulatory factors under eight dominant tree species in August 2022. We captured 567 soil fauna (except for termites and ants), belonging to 3 phyla, 10 classes, 26 orders, and 99 families, with Achipteriidae, Trygoniidae, Poduridae, and Isotomidae as the dominant species. Tree species significantly affected soil fauna abundance, following an order: Michelia macclurei > Elaeocarpus decipiens > Castanopsis carlesii > Cunninghamia lanceolata > Lindera communis > Schima superba > Pinus massoniana > Liquidambar formosana. However, the richness, evenness, and diversity of soil fauna under different tree species were significantly different. Richness and diversity of M. macclurei, C. lanceolatas soil fauna were relatively high, while L. formosana, C. carlesii were relatively low. The evenness of meso-microfauna of L. formosana was the highest, which was significantly higher than that of M. macclureis and E. decipiens. The evenness of macrofauna and total soil fauna was not significantly different among the eight tree species. In addition, the abundance of omnivores and herbivores soil fauna was relatively high under M. macclurei, but relatively low under E. decipiens. The abundance of saprophages and predators soil fauna of E. decipiens, M. macclurei was higher than L. formosana, while saprophages was mainly meso-microfauna. Results of redundancy analysis showed that litter N, C:N, and K were the main factors affecting soil fauna community structure. The results indicated that the tree species with thicker litter layer and higher N and K contents may be conducive to enhancing the diversity of soil fauna community and affecting the distribution of different functional groups, thus contributing to the maintenance of forest biodiversity.

Effects of different fertilizer applications on citrus rhizosphere soil quality and arbuscular mycorrhizae colonization

WANG Peng, WEN Mingxia, JIN Longfei, LIU Feng, LU Qi, CAO Mingao, HUANG Bei, WU Shaohui

2023, 34(10):  2805-2812.  doi:10.13287/j.1001-9332.202310.012

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To understand the effects of different fertilizer applications on soil quality and arbuscular mycorrhizal colonization, we examined the changes in soil physical and chemical properties, mycorrhizal colonization and propagules, and their relationships in citrus under inorganic fertilization (IF), organic fertilization (OF), combined organic and inorganic fertilization (CF), and no fertilization (CK) treatments. Results showed that all fertilization treatments improved the content of rhizospheric soil organic carbon (SOC), nutrient contents, and electrical conductivity (EC). Both CF and OF significantly increased soil pH, soil aggregate stability, activities of urease, catalase, and sucrase, and the colonization and reproduction of arbuscular mycorrhizae fungi (AMF) in citrus rhizosphere. However, IF treatment significantly decreased soil pH and the colonization and reproduction of AMF in citrus rhizosphere. The number of mycorrhizal colonization and propagation was positively correlated with soil aggregate stability, SOC content, total nitrogen content, total phosphorus content, urease activity, and soil pH. Combined with the principal component analysis, we concluded that application of inorganic fertilizer alone could cause soil acidification and inhibit AMF colonization in citrus orchards. In contrast, organic fertilizer combined with inorganic fertilizer in citrus could improve the soil quality and AMF colonization.

Characteristics of gut microbiome communities in the invasive African giant snail under urbanization gradient

XIE Jing, ZHANG Yiyue, TANG Zhonghui, SUN Xin

2023, 34(10):  2813-2819.  doi:10.13287/j.1001-9332.202310.030

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To investigate the diversity and community structure of gut microbiome of the invasive species, Achatina fulica, along an urbanization gradient, we collected 30 A. fulica samples from five parks in the urban, suburban, and rural areas of Xiamen City. Using full-length 16S rRNA gene sequencing performed by the third generation PacBio sequencing platform, we analyzed the community characteristics of gut microbiome and soil microbiome in different habitats. We found a significant disparity between the composition of gut microbiome of A. fulica and that of the soil microbiome in their habitats. Furthermore, the gut microbiome of A. fulica were more sensitive to urbanization. The microbial α-diversity indices (Sobs, Chao, Shannon indices) in the soil of A. fulica habitats were consistently higher than those within their guts. Despite the similar β-diversity indices of microbial communities in urban, suburban, and rural soils, we found a significant discrepancy in gut microbiome composition. Urbanization significantly influenced A. fulica gut microbiome composition. Gut microbiome of A. fulica in urban and suburban regions primarily consisted of Enterobacteriaceae, Xanthomonadaceae, and Mycoplasmataceae, while that in rural areas chiefly composed of Streptococcaceae and Paenibacillaceae. The diversity and abundance of potential human pathogenic bacteria within the gut microbiome of A. fulica significantly increased in urban environments, suggesting that urbanization escalated the risk of A. fulica transmitting potential pathogens.

Temporal-spatial distribution of functional feeding groups of macroinvertebrate and biological evaluation of water quality in Xinyang section of the Huaihe River main stream

ZHANG Zehao, ZHANG Jingxiao, YU Miao, GAO Yunni, DONG Jing, SONG Dongying, LI Xuejun

2023, 34(10):  2820-2826.  doi:10.13287/j.1001-9332.202310.028

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From November 2021 to September 2022, we conducted four field surveys on macroinvertebrates and water environmental factors in Xinyang section of the Huaihe River main stream. We analyzed the structure and spatiotemporal distribution characteristics of the functional feeding groups of macroinvertebrates, and evaluated river water quality. A total of 73 macroinvertebrate species were collected in the basin, belonging to 42 families, 7 classes, and 3 phyla. The dominant species of macroinvertebrates changed significantly in different months, with Exopalaemon modestus being the absolute advantage species in the basin in July and September 2022. In different sampling months, the functional feeding group of macroinvertebrates was mainly dominated by shredders, accounting for 35.9%. The results of redundancy analysis showed that the main environmental factors affecting the distribution of functional feeding groups of macroinvertebrates varied across different months, with conductivity in February, temperature in July, and oxidation-reduction potential in September and November. The evaluation based on the biolo-gical index and Shannon index of macroinvertebrates indicated that water quality in the investigated section was at a light pollution level.

Big data analysis of coastal illegal fishing from the perspective of compensation of ecological and environmental damage

ZHANG Hushun, ZHONG Xiaming, XIONG Ying, WU Xiaorui

2023, 34(10):  2827-2834.  doi:10.13287/j.1001-9332.202310.032

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Illegal fishing is one of the sources of marine ecological damage. The implementation of compensation of ecological and environmental damage in this field is poorly understood. In this study, we examined data pertaining to coastal illegal fishing cases during 2018-2022 using the big data publicly made available by China Judgement Online. The main results included: 1) there are numerous types of illegal fishing, and more efforts should focus on the nature and extent of illegal fishing, with electrofishing and trawl being suitable entry points; 2) Special attention should be paid to the variation characteristics of rakes in the range of high illegal catch weight and value. It was suggested to optimize and adjust its management mode to avoid the frequent occurrence of such illegal fishing cases of rake; 3) The varieties of assessment models increased the uncertainty of damages computation, which might be reduced by establishing strong criteria for value quantification and damage assessment; 4) There is limited scientific support for the compensation for releasing the most popular ecological restoration technique for illegal fishing. As a result, the “compensation” design for “restoration” should be implemented, while the potential for additional restoration methods should be investigated.

Reviews

Effect of environmental factors on mineral soil respiration: A review

LIU Yuanhao, DU Xulong, HUANG Jinxue, XIONG Decheng

2023, 34(10):  2835-2844.  doi:10.13287/j.1001-9332.202310.015

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Mineral soil respiration, a major component of CO₂ emissions from soil to atmosphere, plays a critical role in driving terrestrial ecosystem carbon cycling and is highly sensitive to environmental changes, including soil temperature, soil moisture, and substrate availability. The changes of environmental factors can affect mineral soil respiration and its temperature sensitivity thereby alters global carbon balance. We reviewed studies on the effects of environmental factors on mineral soil respiration and its temperature sensitivity. The effect of environmental factors on mineral soil respiration and its temperature sensitivity significantly differed among ecosystems. Environmental factors directly and indirectly affect mineral soil respiration and its temperature sensitivity by altering soil microbial biomass and community structure, extracellular enzyme activity, and soil porosity. Based on the results of this review, we suggested: 1) combining multiple observation techniques and methods to study the effects of environmental factors on mineral soil respiration; 2) exploring the interactive effects of multiple environmental factors on mineral soil respiration; 3) carrying out experiments on mineral soil respiration at different temporal and spatial scales; 4) improving the prediction model of mineral soil respiration and its temperature sensitivity; 5) streng-thening the role of substrate supply of recent photosynthates in the regulation of mineral soil respiration and its temperature sensitivity.

Distribution, hazard evaluation, and control measures of allergenic airborne pollen

MENG Ling, YANG Lei, WANG Qiaohuan, WANG Junjie

2023, 34(10):  2845-2853.  doi:10.13287/j.1001-9332.202310.001

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Allergenic airborne pollen can induce hay fever such as rhinitis and asthma. Many studies have been conducted on the allergenic pollution caused by airborne pollen. We synthesized available studies to summarize the temporal and spatial distributions of airborne pollen and influencing meteorological factors. We further summarized and discussed the hazards of airborne pollen sensitization on human health and evaluation indicators for classifying hazard levels. We described the research progress of prevention and control measures of airborne pollen induced pollution from the perspectives of source control, route monitoring, and prevention of susceptible population. Considering the limitations of current studies, we proposed some research directions on allergenic airborne pollen. The types of allergenic plants needed to be clearly identified and allergentic potential should be quantitatively identified. The methods of pollen collection and concentration monitoring needed to be improved and standardized. This review could provide a scientific guidance for the study on preventing and treating pollen allergies as well as optimizing urban green space planning.

Improvement of crop pollination service through planting field-side companion plants: Current understan-ding and prospect

WANG Hua, WANG Hui, SHAO Xiaoli, YE Zhongming

2023, 34(10):  2854-2860.  doi:10.13287/j.1001-9332.202310.018

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Insect pollinators play a vital role in global crop pollination. Due to climate change, agricultural intensification, and urbanization in recent decades, insect pollinator abundance and species richness have declined rapidly at global and regional scales. Insufficient pollination on croplands is becoming a significant challenge worldwide. In recent years, planting of field-side companion plants that flower concurrently in the vacant space on croplands has been proposed as an effective measure in developed countries to improve pollinator abundance and diversity. These companion plants can provide stable food sources (such as nectar and pollen) and nesting sites for pollinators. Related studies in China are still limited. We reviewed the global research status on the effects of field-side companion plants on crop pollination services, focused on the factors influencing the impacts of co-flowering plants on crop pollination, optimal selection principles for companion plants, and put forward perspectives for application in Chinese agriculture.

Application of stable isotope techniques in soil food web research

WANG Xiao, LIANG Siwei, TIAN Yijia, LIU Xiaotong, LIANG Wenju, ZHANG Xiaoke

2023, 34(10):  2861-2870.  doi:10.13287/j.1001-9332.202310.013

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Stable isotope technique is important for understanding the structure and function of soil food web, which is considered as a belowground black box. We reviewed typical application cases of stable isotope techniques in the research of soil food webs, including to determine food sources and feeding preferences of soil fauna by using isotopes, and to analyze the trophic structure of soil food webs through isotope fractionation effects during the process of feeding and nutrient sequestration by soil fauna. Additionally, stable isotope techniques could reveal the role of soil biota at different trophic levels within soil food web in ecosystem matter and energy flow, which favored to carry out accurate and efficient research on the contribution of soil food webs to soil carbon and nitrogen cycling process and the corresponding influence mechanism. We further put forward the limitations of current stable isotope techniques and the future development directions.

Review on building energy saving and outdoor cooling effect of vertical greenery systems

PAN Lan, ZHENG Xiaona, LUO Shuang, MAO Huijun, MENG Qinglin, CHEN Jinrui

2023, 34(10):  2871-2880.  doi:10.13287/j.1001-9332.202310.020

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Vertical greenery system (VGS) is a sustainable solution to promote building energy saving and emission reduction, mitigate the urban heat island effect, as well as a crucial component of urban ecological construction. We summarized four main mechanisms of the thermal effects of VGSs, including shading effect, evapotranspiration effect, thermal insulation effect, and wind control effect. We elucidated the effects of VGSs on building cooling and energy saving, and analyzed the cooling effects of VGSs on plant canopy and outdoor ambient air, as well as their influence on mitigating the urban heat island effect. Based on available research on the thermal effects of VGSs, we identified key directions for future research, aiming to expedite the development of green cities and achieve carbon neutrality.