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    10 February 2021, Volume 40 Issue 2
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    Effects of freezing and thawing cycle on seed germination of desert ephemeral plants.
    ZHANG Yu-lin, YIN Ben-feng, TAO Ye, ZHOU Xiao-bing, ZHANG Yuan-ming
    2021, 40(2):  301-312.  doi:10.13292/j.1000-4890.202102.005
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    The alternation of freezing and thawing in desert area significantly changes soil temperature and water conditions, with consequences on seed germination of desert plants. Here, we examined the effects of freezing and thawing process on seed germination of four typical ephemeral plant species, Eremopyrum orientale, Lappula patula, Erodium oxyrrhynchum and Alyssum linifollum, in the Gurbantunggut Desert. We measured the seed germination parameters (germination rate, germination potential, germination index, and seed vigor) of those four species under the treatments of different temperatures, soil moisture, and freezing-thawing cycles. The results showed that temperature did not affect seed germination parameters of the four species, whereas water condition, cycle number of freezing and thawing, and their interaction showed significant effects (except for the effects of soil moisture on A. linifollum). In addition, increased freezing and thawing times promoted seed vigor and seed germination after the freezing and thawing treatments, especially under low moisture condition. High soil moisture in the freezing and thawing period significantly reduced the seed germination rate of E. orientale, but such effects on other species depended on day temperature and numbers of freezing and thawing cycles. Under the same soil moisture condition, high temperature during the freezing and thawing period usually promoted seed germination. In general, freeze-thaw process had a significant species-specific effect on seed germination of desert ephemeral plants, which would lead to speciesspecific variation in seedling growth after the freeze-thaw period and thus affect plant community structure in the desert.
    Carbon, nitrogen and phosphorus stoichiometry and nutrient resorption of Pinus sylvestris var. mongolica under different densities.
    WANG Kai, NA En-hang, ZHANG Ri-sheng, GAO Shuang, LIU Jian-hua
    2021, 40(2):  313-322.  doi:DOI: 10.13292/j.1000-4890.202102.016
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    We examined the carbon (C), nitrogen (N) and phosphorus (P) stoichiometry in different organs (current-year needle, one-year-old needle, current-year branch, one-year-old branch, and fine root) along with the N and P resorption efficiencies in needles of Pinus sylvestris var. mongolica in pure forest with six densities (490, 750, 1110, 1550, 1930 and 2560 trees·hm-2). The results showed that C concentrations in the current-year and one-year-old needles and P concentrations in the current-year and one-year-old branches exhibited downward trends with increasing stand density, except for the 1550 trees·hm-2 stand. With the increases of stand density, C concentrations in current-year branch, one-year-old branch and fine root, the N concentrations in all organs, and P concentrations in current-year needle, one-year-old needle and fine root tended to increase and then decrease, with the highest values in the 1550 trees·hm-2 stand. The C∶N in current-year needle, one-year-old needle and fine root, C∶P in current-year needle and branch, and N∶P in current-year needle, current-year and one-year-old branches displayed decreasing and then increasing trends with increasing stand density, whereas C∶P in one-year-old needle and branch showed an upward trend. With increasing stand density, C concentrations in leaf litter increased and then decreased, N concentrations exhibited an increasing trend, and P concentrations decreased and then increased. With increasing stand density, N resorption efficiency and the ratio of N resorption efficiency to P resorption efficiency decreased, and P resorption efficiency increased and then decreased. These findings indicated that N limitation weakened but P limitation enhanced with increasing stand density. The optimal management density for P. sylvestris var. mongolica stand should be 1550 trees·hm-2, in which more nutrients are allocated to needles and fine roots and thus contribute to high growth rate.
    Plant-soil feedback and plant-plant interaction in the glacier retreat area of Gongga Mountain.
    LU Qi, DU Liu-shan, DUAN Bao-li, LEI Yan-bao
    2021, 40(2):  323-331.  doi:DOI: 10.13292/j.1000-4890.202102.009
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    Plant-soil feedback is a key link for revealing the dynamics of terrestrial communities, thus laying a foundation to improve our understanding on the interactions among different plant groups and on the vegetation successional trajectories. We explored the relationships between soils and dominant plant species at three stages of the glacier retreat area of the Gongga Mountain including the early succession (5-10 years), mid-term succession (30-40 years), and late succession (80-100 years). The results showed that: (1) Plant-soil feedback significantly affected plant biomass in the native soil. Hippophae rhamnoidesgrew worst in the native soil of the early succession, with a negative plant-soil feedback coefficient. In the middle succession, the feedback coefficient of Populus purdomii tended to be zero. Abies fabri grew best in native soil at the late succession, with a positive feedback coefficient. (2) The competition interaction index between the early succession species H. rhamnoses and species of middle and late succession was negative, while it closed to zero for mid-succession species P. purdomii and Salix rehderiana, and was positive for the late succession species A. fabriand Picea brachytyla mixed with early and mid-succession species. Therefore, plant-soil feedback shifted from negative in early succession, neutral in mid-term succession, to positive in late succession. The early-succession species H. rhamnoides promoted the growth of species in later stages. P. purdomiiand S. rehderianain the mid-succession stage had no interaction with early and late succession species. Late-succession species A. fabriand P. brachytylawere more conducive to competing with early and mid-succession species. The results suggest that plant-soil feedback and plantplant interaction together drive the rapid succession of plant community up to the climax community in the glacier retreat area of Gongga Mountain.
    Seed germination and seedling growth of Medicago sativa in response to the variations of temperature, light, and burial depth.
    LI Yang, QI Wen-wen, LI Shao-yang, ZHAO Dan-dan, LI Jing-yu, MA Hong-yuan
    2021, 40(2):  332-339.  doi:DOI: 10.13292/j.1000-4890.202102.020
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    Medicago sativa is an important forage in global cultivated grassland. Aiming to provide management guide for M. sativa grassland, we investigated the responses of seed germination and seedling growth to the variations of important environmental factors (temperature, light, and burial depth). We compared seed germination of M. sativa at five constant thermal treatments (10, 15, 20, 25, and 30 ℃) and five alternative temperatures (6/15, 10/20, 15/25, 15/30, and 20/30 ℃), accompanied with two light regimes, i.e. 12 h light/12 h dark and 24 h dark. Five sowing depths (1, 2, 3, 4, and 5 cm) were carried out to explore the effects of soil burial depth on seed emergence and seedling growth of M. sativa. Results showed that M. sativa could germinate to 50%-88% within a large temperature range. Light availability significantly promoted seed germination, especially at 10, 15, 30, 10/20 and 15/30 ℃. Seed germination ranged from 69% to 88% under light treatment and from 50% to 77% under dark treatment. There were no significant differences in seedling emergence percentage across different burial depths. Fresh and dry weight of shoot, root length and weight of the 1-2 cm burial depth treatments were all significantly higher than that of 3-5 cm burial depth treatments. In conclusion, M. stativa could germinate under broad ranges of constant or alternating temperatures of 6-30 ℃, indicating that there was no strict season requirement for sowing seeds. Light significantly promoted seed germination of M. stativa. The suitable burial depth was within 1-2 cm.
    Effects of apple-soybean intercropping on soil nutrient and microbial biomass distribution in sandy land of northwest Liaoning Province.
    KONG Tao, LIU Zi-wei, SHEN Hai-ou, WANG Zhen-yu, WANG Dong-li, SUN Pu-fan, WANG Yi-xiang
    2021, 40(2):  340-351.  doi:DOI: 10.13292/j.1000-4890.202102.029
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    We examined the distribution characteristics of soil nutrients and microbial biomass in fruit-crop intercropping system (apple (Malus pumila)soybean (Glycine max)) in a sandy land of northwestern Liaoning. Soil nutrients and microbial biomass in the 0-60 cm soil layer and the horizontal distance of 0-300 cm in the intercropping system were measured, and further compared with that in soybean monoculture and apple monoculture. The results showed that soil nutrient was poor in the apple-soybean intercropping system, with total nitrogen, available nitrogen and available phosphorus being extremely deficient. Horizontally, with the increases of the distance from apple trees, the concentrations of soil organic matter, available nitrogen, total phosphorus and available phosphorus in the intercropping system were decreased first, then increased, and eventually tended to be stable. The nutrient competitive area was located at the fruit tree belt \[0, 100 cm). At the vertical direction, all types of nutrients in the apple soybean intercropping system exhibited surface aggregation, with nutrients content in topsoil (0-20 cm) being significantly higher than that in deep soil (20-60 cm). Soil microbial biomass carbon and nitrogen and the quantity of bacteria were high in fruit tree belt and topsoil. There were significant differences of nutrient contents between intercropping and monoculture in topsoil, with the differences being narrowed with the deepening of soil layer. Except the alkaline hydrolysis nitrogen, the effects of intercropping system on soil nutrients were negative, which could not meet the requirement of intercropping system. The requirement of the intercropping system for soil nitrogen and phosphorus was substantial. In conclusion, there was an obvious competitive relationship in the apple-soybean intercropping system, especially in the fruit tree belt. The application of nitrogen and phosphate fertilizers in the intercropping system should be strengthened.
    Photosynthetic and physiological responses of six shrub species to drought dress in northern Hebei Province.
    ZHANG Heng-shuo, ZHA Tong-gang, LI Xiao, PENG Dong, JI Xiao-dong, ZHANG Zhi-qiang, ZHANG Hai-jiang, XUE Zhi-guo
    2021, 40(2):  352-362.  doi:DOI: 10.13292/j.1000-4890.202102.015
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    To provide theoretical support for species selection, breeding and vegetation restoration in northern Hebei Province, we assessed the ecophysiological adaptability and drought resistance of different shrub species to drought stress, including four native shrub species (Potentilla fruticosa, Artemisia ordosica, Ostryopsis davidiana, and Lespedeza bicolor) and two introduced shrub species (Hippophae rhamnoides, and Vitex negundovar. heterophylla). Four water levels (85%±5%, 70%±5%, 50%±5% and 35%±5% of field water-holding capacity, designated as T1, T2, T3 and T4, respectively) were set up for indoor pot experiment of drought stress. We measured biomass, plant height change rate, root/shoot ratio, relative chlorophyll content (SPAD value), leaf water potential, net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr) and water use efficiency (WUE). The results showed that: (1) Under drought stress, the root/shoot ratio of P. fruticosa and A. ordosica significantly increased (P<0.05), and the decrease of biomass and plant height change rate was limited, while biomass and the change rate of plant height of O. davidiana and V. negundo var. heterophyllawere significantly reduced (P<0.05). (2) Under drought stress, the relative content of chlorophyll, leaf water potential and photosynthesis of all the six species decreased in different degrees, while WUE varied with the decreasing water availability. WUE of L. bicolor decreased significantly under T3 treatment (P<0.05), while H. rhamnoides and P. fruticosaincreased significantly under T3 treatment (P<0.05) and T4 treatment (P<0.05), respectively. (3) The absolute value of the load between the growth, morphology, eco-physiological and photosynthetic indices of shrubs and the main components was greater than 0.7, and the comprehensive score order of the main components of each shrub species was: P. fruticosa>A. ordosica>L. bicolor>H. rhamnoides>O. davidiana>V. negundo var.heterophylla. Except P. fruticosa, the scores of factors of other shrub species under T4 treatment were negative, suggesting strong drought resistance. The native shrub species P. fruticosa and A. ordosica should be planted in the arid area of northern Hebei Province, while the native shrub species L. bicolorand the introduced shrub species H. rhamnoides can be selected as the vegetation community restoration species in the area with better water condition.
    The coupling effects of water and nitrogen addition on the growth characteristics of Moringa oleifera. #br#
    PENG Zhong-tong, LIN Jia-na, LIU Li, CHEN Yi-qun, WANG Yi-ying, ZHANG Yuan-dong, ZENG Shu-cai, MO Qi-feng
    2021, 40(2):  363-372.  doi:DOI: 10.13292/j.1000-4890.202102.022
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    Moringa oleiferahas important economic value. The availability of soil water and nitrogen is of great significance for their growth. In this study, we examined the coupling effects of soil water and nitrogen addition on the growth and biomass accumulation of Moringa oleifera ‘PKM I’ in the greenhouse of the Experimental Base of Ecology Teaching, College of Resources and Environment, South China Agricultural University. There were three water levels, including 40% (W1), 60% (W2), 80% (W3) of field water holding capacity, and four nitrogen levels, including 0 g·plant-1 (N0), 0.6 g·plant-1 (N1), 1.8 g·plant-1 (N2), and 3.6 g·plant-1 (N3), resulting in 12 treatments. The results showed that: (1) The height and basal diameter of Moringa oleifera-under low N level (N1) were generally higher than those under other treatments, whereas high N and W levels inhibited growth. (2) With respect to the branching pattern, under low W level, the branch length at each level, the overall branching rate, and the stepwise branching rate decreased with increased N fertilization level. The medium N fertilization following the higher W level was optimal for the fast growth of Moringa oleifera. (3) The biomass of Moringa oleiferadecreased under the high N level. Under no N addition, the biomass of Moringa oleiferawould decrease with the increasing W level. (4) In terms of comprehensive morphology, the W1N3 treatment significantly increased the root/shoot ratio (R/S). The slenderness index (SI) under W2N2 treatment was the lowest, indicating the best growth quality. Bulk index (BI) under the medium N level was higher than under other treatments, with the highest value under the W2N1 treatment. The Dickson quality index (DQI) under W2N2 treatment was the highest. These results suggest that suitable combination of water and N fertilizer could efficiently enhance the growth and biomass accumulation of Moringa oleifera.
    The correlation between economic traits of soapberry fruit and environmental factors.
    WANG Li-xian, LIU Ji-ming, XU Yuan-yuan, ZHAO Guo-chun, WANG Xin, RUI Xue, JIA Li-ming
    2021, 40(2):  373-380.  doi:DOI: 10.13292/j.1000-4890.202102.030
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    Soapberry (Sapindusmukorossi) is widely distributed in southern China, the economic traits of fruits of which from different provenances are significantly different. It is not clear which environmental factors drive the variation of economic traits. In this study, we examined the economic traits of the fruits of 47 natural germplasms from four provinces on the east, west, south, and north of its natural distribution borders in China. Pearson correlation and redundancy analysis were used to analyze the relationship between fruit economic traits and environmental factors. There was a significantly positive correlation between the pericarp saponins content (PSC) and mean annual temperature and extreme low temperature, and a negative correlation with latitude and relative air humidity, indicating that higher PSC fruits tend to develop in areas with relatively higher temperature and dry air. Kernel oil content (OC) was significantly negatively correlated with longitude and positively with altitude. The results of RDA ranking model showed that longitude, latitude, and relative humidity were the main factors explaining the differences in the economic traits of fruits from different provenances. Latitude was the most important factor affecting the fruit economic traits, with a variance explanation rate of 29.1%. In selection and breeding of superior germplasm of Sapindusmukorossi, superior germplasm for saponin can be found at areas with relatively high temperature and low humidity, while higher OC germplasm always grow in high-altitude areas. To achieve higher economic benefits in production, we suggest plant soapberry in relatively low latitude, low longitude and low relative humidity areas.
    Effects of depth to water table and micro-topography on microbial activity and methane functional genes of peat bog in Jinchuan.
    ZHANG Xue-bing, MENG Di, CHEN Lei, WANG Zi-tong, YANG Qian-nan, CHANG Qing, FAN Xian-lei, LIU Zi-ping, BAI E
    2021, 40(2):  381-391.  doi:DOI: 10.13292/j.1000-4890.202102.002
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    Peat bogs are the most effective terrestrial ecosystems for long-term carbon storage. Hydrologic characteristics and micro-topography may affect carbon storage in peatlands by regulating the composition and function of microbial communities. In the site located in the peat bog of Jinchuan in Changbai Mountain, we collected soil samples in hummock and hollow of Carex schmidtii from eight different levels of the depth to water table (-10, -1, 0, 4, 10, 13, 14 and 18 cm), to explore the effects of depth to water table and microtopography on soil microbial biomass carbon and nitrogen, enzyme activity, and methane functional genes. Results showed that the effects of the depth to water table on the content of microbial biomass carbon and nitrogen differed across different soil layers, with a significant positive correlation with microbial biomass carbon and nitrogen in the 30-45 cm soil layer of hummock and the 0-15 cm soil layer of hollow. The activities of enzymes (β-1,4-glucosidase and β-1,4-Nacetylglucosamine glycosidase) related with soil carbon and nitrogen cycling were significantly positively correlated with the depth to water table and regulated by soil layer, while the phosphatase activities were not correlated with the depth to water table. In addition, the depth to water table had a significant negative correlation with the abundance of methanogenesis bacteria (the copy number of mcrA functional gene per gram dry soil), and a significant positive correlation with the abundance of methaneoxidizing bacteria (the copy number of pmoA functional gene per gram dry soil), with a stronger effect of the depth to water table on the abundance of methanogenesis bacteria. The microtopography significantly affected microbial biomass carbon and nitrogen, with higher microbial biomass carbon and nitrogen in hummock than in hollow at the same 15-30 cm soil layer and higher microbial biomass carbon in 15-30 cm soil layer of hollow than in 0-15 cm soil layer of hummock. Themicro topography significantly affected the abundance of methaneoxidizing bacteria, which was higher in hummock than in hollow in the same 15-30 cm soil layer. Our results indicated that the spatial heterogeneity of peatlands would affect microbial activity, which should be fully considered in scaling up the results from local to large scale.

     

    Effects of nitrogen application and intercropping on soil aggregates-associated potassium distribution and crop potassium uptake.
    YI Wen-bo, WANG Ding, LI Huan, HE Shu-ran, ZHAO Ping, LONG Guang-qiang
    2021, 40(2):  392-401.  doi:DOI: 10.13292/j.1000-4890.202102.007
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    We examined the effects of N application rate and cropping pattern on the distribution of soil aggregateassociated K in a 6-year field experiment of maize monocropping, potato monocropping and intercropping of maize and potato under two nitrogen (N) application rates (low N and high N). Soil aggregates were classified using wet sieving method, and the contents of total potassium (K), exchangeable K and nonexchangeable K in each aggregate were measured. The results showed that soil aggregates were mainly composed of mediumsized aggregates (0.25-2 mm). The allocated K in mediumsized aggregates accounted for 60.6%-65.0% of soil total K reserves. The cropping pattern and N application rate significantly affected the content and reserve of aggregateassociated non-exchangeable K, but did not affect that of total K and exchangeable K. Under high N application level, intercropping significantly increased the reserves of total K and nonexchangeable K by 57.6% and 73.6% for large-sized aggregates (>2 mm), and 21.1% and 41.5% for medium-sized aggregates (0.25-2 mm), respectively, compared with the weighted average of monocropping. Intercropping increased the K uptake by maize, but reduced that of potato. Except for the potato monocropping, the proportion of exchangeable K and nonexchangeable K in aggregates (>0.25 mm) was significantly positively correlated with crop K uptake in monocropping (except for potato monocropping) and intercropping systems. In conclusion, intercropping and N application could increase the non-exchangeable K and total K reserves of larger-sized aggregates in soil, with positive consequences on the preservation and sustainable supply of soil K.
    Phytoplankton community characteristics and water quality evaluation in Shuifeng Reservoir.
    WEI Hong-xiang, JIANG Xiang-hui, ZHANG Tao, WANG Xing-bing, KOU Ling-xiao, LIU Yong
    2021, 40(2):  402-411.  doi:DOI: 10.13292/j.1000-4890.202102.034
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    A total of 19 investigations were conducted on the phytoplankton community structure and water quality in Shuifeng Reservoir during June 2010 to October 2019. A total of 76 phytoplankton species (abundance >1000 cells·L-1) were recorded, which belonged to 7 phyla and 43 genera. There were 33 species of Bacillariophyta, 27 species of Chlorophyta, 6 species of Cyanophyta, 5 species of Euglenophyta, 2 species of Cryptophyta, and 1 species of Pyrrophyta. The abundance of phytoplankton was 1.20×104-6.03×106 cells·L-1, with an average of 7.13×105 cells·L-1. The dominant species were Aphanizomenon issatschenkoi, Dinobryon divergens, Melosira granulata, Cyclotella meneghiniana, Cyclotella comta, Fragilaria crotonensis, Synedra acus var.angustissima, Asterionella formosa, Mougeotia sp., and Closterium acicular var. subprorum. Indicated from the dominant species, pollution-indicating species, abundance of phytoplankton, Shannon diversity index and trophic level index, Shuifeng Reservoir was at a mesotrophic state or mesotrophic-eutrophic state. The comprehensive index of algae indicated that Shuifeng Reservoir was at a eutrophic state. The biomass of phytoplankton indicated that Shuifeng Reservoir was at an oligotrophic state. Taken together, the Shuifeng Reservoir was at the mesotrophic state.
    Community structure and ecological warning of reef-associated fish and macrobenthos in the Yalong Bay.
    HUANG Ding-yong, WANG Jian-jia, CHEN Gan-lin, ZHENG Xin-qing
    2021, 40(2):  412-426.  doi:DOI: 10.13292/j.1000-4890.202102.033
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    Reef-associated community such as fish and macrobenthos is an important component of coral reef ecosystems. The information of these communities is essential for a comprehensive assessment of the health status of coral reef ecosystems. Based on video transect method, a survey was conducted to investigate reef-associated fish and macrobenthos at 17 stations of coral reef area in the Yalong Bay, Sanya City, Hainan Province at the end of December 2018. We analyzed the community structure, quantitative distribution and similarity of the fish and macrobenthos, revealed the ecological warning, and put forward the corresponding regulatory suggestions, aiming at protecting and restoring the coral reefs in the Yalong Bay. A total of 35 species, 21 genera and 8 families, mainly composed of families Pomacentridae and Labridae, were recorded at the 12 stations of west bank of the Yalong Bay, Dongpai and Xipai reefs. The average density of fish was 0.20 ind·m-2. Pomacentrus chrysurus, Stegastes obreptus and Chromis lepidolepis were the dominant species. Fish resource in the Yalong Bay had been declining in the past 15 years and almost exhausted to date. On the other hand, macrobenthos were dominated by soft corals, benthic macroalgae, sea lilies and sea urchins. The quantitative distribution differed across various groups. The abundance of organisms harmful to hermatypic corals, Drupella and Acanthaster planci, were very low and fail to threat the corals. As a whole, the reef-associated fish and macrobenthos community at west bank of the Yalong Bay were quite different from those at Dongpai and Xipai reefs, reflecting differences in the environment features between the shore and offshore reefs. The environmental conditions at the west bank near the mouth of the Yalong Bay may be more similar to the offshore reefs. Due to the relatively higher abundance of benthic macroalgae and the possible eutrophication trend at some stations, keeping the balance between the population of damselfish or other herbivorous fishes and algae is particularly important for restoring and maintaining the health of reef ecosystem in the Yalong Bay. Meanwhile, management of terrigenous nutrients from Qingmei River and other sources was also the key to control the proliferation of macroalgae in the Yalong Bay. Compared with sea cucumber, crinoids were less dependent on benthic macroalgae. There was no significant correlation between hermatypic coral coverage and the quantity of reefassociated macro-organisms, probably due to the severe degradation of coral reefs in the Yalong Bay as well as the relatively low spatial heterogeneity of coral reefs mainly comprising by massive coral species. In order to better protect coral reefs of the Yalong Bay, more attention should be paid on the management of water quality of the Yalong Bay, and the supervision of fishing, diving and other tourism activities. It is necessary to implement a longterm fishing ban for restoration of fish resource immediately and perform a regular monitoring on the population changes of key species.
    Effects of anthropogenic inputs on hydrochemical compositions of water in the Shaying River Basin.
    WU Yang-yang, LIU Yun-tao, ZHANG Dong, LI Chuan, LI Yu-hong, ZOU Shuang, ZHU Shuang-shuang, HUANG Xing-yu, MA Bing-juan
    2021, 40(2):  427-441.  doi:DOI: 10.13292/j.1000-4890.202102.004
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    Hydrochemical compositions of river water have been profoundly altered by anthropogenic inputs, resulting in increased ion fluxes to the ocean and affecting the global material cycling. Identifying the pathways and ranges of anthropogenic contributions to river water is important for quantifying the influences of anthropogenic activities on global material cycling. Shaying River is the largest tributary in the upstream of Huai River, which has been seriously disturbed by anthropogenic inputs for a long time. Hence, it was a suitable place to examine the variations of riverine material fluxes caused by anthropogenic activities. The results would shed light on the related processes and impacts of anthropogenic input on hydrochemical compositions of riverwater. A total of 41 samples of river water and 12 samples of groundwater  were collected in December 2019 (a normal period of water level). Hydrochemical compositions and water isotope values were analyzed, with the aim to elucidate the pathways, ranges and spatial distributions of anthropogenic inputs, and to constrain the controlling factors in the Shaying River Basin. Theresults showed that major anion and cation in most river water and groundwater was bicarbonate (HCO3-) and calcium (Ca2+), respectively, and that chloride (Cl-) and sodium (Na+) was dominated anion and cation in the downstream of Shaying River, respectively. The chemical weathering of carbonate and silicate, industrial wastewater and sewage, and agricultural non-point pollution sources were identified as the main factors controlling hydrochemical compositions of water. Most of Sha River water and the upstream water of the Ying River were primarily controlled by rock chemical weathering, and less affected by industrial wastewater and sewage. However, the whole Jialu River and the mainstream of Shaying River were heavily affected by industrial wastewater and sewage. Most groundwater was also influenced by agricultural nopoint pollution sources. The chloride-alkali index was less than zero because of the exchange betweenadsorbed sodium, potassium cations in silicate and dissolved calcium, magnesium cations in the local groundwater, rendering more released Na+ and K+ in the groundwater. However, the higher Na+ and K+ concentrations in river water than those in groundwater, which were mainly sourced from industrial wastewater and sewage inputs rather than from groundwater inputs. Decreased concentrations of conservative Cl- along the Shaying River mainstream was resulted from the discharge of groundwater with low Cl- concentrations and dilution by downstream damed river water. The dexcess values became more positive, indicating extensive water evaporation of downstream river water. Our results confirmed the effects of anthropogenic input on river water and provided a profound theoretical footstone for further water pollution treatment
    Distribution characteristics of microbial communities at a depth of 700 m level of Quantai coal mine in Xuzhou.
    LI Wen-bo, FENG Qi-yan, GAO Bo, CHEN Di, LI Xiang-dong
    2021, 40(2):  442-452.  doi:DOI: 10.13292/j.1000-4890.202102.010
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    There are obvious differences between underground coal mine and surface environment. The studies of the distribution and diversity of microbial community in the underground coal mines are important for exploring the water rockgasbiological mechanism. In this study, eight coal deposit samples were collected from the level of -700 m in Quantai Coal Mine, Xuzhou, East China. The physical and chemical indices of the samples were tested and Miseq highthroughput sequencing was performed. A total of 35 bacteria phyla were detected in the eight samples, with Proteobacteria, Firmicutes, and Actinobacteria together accounting for more than 80% of the total abundance. Proteobacteria and Firmicutes were mainly distributed in rock lanes, while Actinobacteria were mainly distributed in coal lanes. The dominant bacterial genera of coal mines included Lactococcus, Pseudomonas, Mycobacterium, and Bacillus. In general, the abundance and diversity of bacterial communities in rock lanes were higher than those in coal lanes. pH was the key factor affecting the abundance of bacterial community in coal mine (R2=0.766,P<0.05) at the phylum level. pH was positively correlated with Actinobacteria, Firmicutes and Latescibacteria, while negatively correlated with other phyla. The concentrations of total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP) and sulfate also affected the community abundance distribution. Therefore, the influence of underground microorganisms should be fully considered when examining coal mine pollution mechanism and pollutant migration.
    The ecological response of Odonata larvae to hydrologic connection blocking in riverside wetlands of the Wusuli River.
    MENG Yao, WU Hai-tao, GUAN Qiang, LU Kang-le
    2021, 40(2):  453-459.  doi:DOI: 10.13292/j.1000-4890.202102.008
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    The composition integrity of macrobenthos community can be used to indicate and predict the health and change trend of aquatic environment, as being widely verified in literature. However, the complexity of sampling at the community level retards their convenient application. Odonata larvae, with an extraordinary amphibious life cycle, are relatively easy to be sampled and recognized among the macrobenthos. The diversity of Odonata larvae and their sensitive reaction to changes of water properties make them a very broad and appropriate bioindicator for wetlands. We analyzed the ecological impacts of the dyke barriers on riverside wetlands and evaluated the environmental indicator role of Odonata larvae on riverside wetlands by comparing the community composition of Odonata larvae in the riverside wetlands of different reaches on both sides of the artificial embankment of the Wusuli River. The results showed that the diversity of Odonata larvae in the riverside wetlands was increasing along the Wusuli River from the upstream to the downstream. Blocking hydrologic connection had a negative effect on the survival and breeding of Odonata larvae. The closer to the downstream, the more significantly the Odonata larvae were affected by artificial dykes. The density of different species on both sides of the dyke had limited variation, while the main difference existed in the relatively large fluctuation range of diversity index value in the sampling sites directly connected with the river hydrology.
    Interactive effects of temperature and salinity on embryonic development rate of Strongylocentrotus intermedius.
    ZHEN Hao, WU Yang-lei, WANG Luo, PEI Hong-lin, TAN Ba-mei, DING Jun, CHANG Ya-qing
    2021, 40(2):  460-469. 
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    The growth of marine organisms is currently challenged by multiple environmental stressors. The early life stages of sea urchin Strongylocentrotus intermedius are sensitive to environmental changes. Temperature and salinity are important environmental factors affecting the growth and development of marine animals. To understand the temperature and salinity tolerance of the early embryonic development of sea urchin and its optimal environmental conditions, we used the central composite design (CCD) and response surface methodology (RSM) to investigate the interactive effects of temperature (12-26 ℃) and salinity (22-34) on the early development of the sea urchin embryo. The quantitative relationship models between temperature, salinity and the fertilization rate, floating rate and metamorphosis rate of sea urchin embryos were established, and the best combination of temperature and salinity was obtained through statistical optimization methods. The results showed that both high and low temperature and salinity were not conducive to the early embryonic development rate of sea urchins. The effect of temperature on the early embryonic development of S intermedius was greater than that of salinity, with certain antagonism between temperature and salinity. The primary effects of temperature and salinity, and the secondary effects of temperature significantly affected the fertilization rate, floating rate, and metamorphosis rate of the S. intermedius embryos (P<0.01). The interactive effects of temperature and salinity significantly affected the embryo fertilization rate and metamorphosis rate of S. intermedius (P<0.05), but did not affect the floating rate. The secondary effect of salinity significantly (P<0.01) affected the fertilization rate of the S. intermedius embryos, but did not affect the floating rate and metamorphic rate. The determination coefficients of the fertilization rate, floating rate and metamorphosis rate were 0.9736, 0.9946, and 0.9925, respectively, indicating that the models were effective and could be used to predict the fertilization rate, floating rate and metamorphosis rate of S. intermedius. The model optimization and verification tests showed that, at 17.71 ℃ and salinity of 31.85, the fertilization rate, floating rate and metamorphosis rate reached the maximum value, with a satisfaction rate of 0.969. Our findings can provide theoretical basis for the artificial breeding of sea urchin.
    Spring and summer diet composition of Tibetan snowcocks.
    JIA Hai-yan, LIU Xiao-qing, TIAN Nong-fu, ZHANG Rui, WANG Rong-rong, LIU Ling-xia, SHI Hong-quan
    2021, 40(2):  470-479.  doi:DOI: 10.13292/j.1000-4890.202102.028
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    Tibetan snowcock (Tetraogallus tibetanus) is a secondclass national protected animal in China, inhabiting in the alpine bare rocks and meadows of QinghaiTibetan Plateau and the adjacent areas. Little information on the diet of Tibetan snowcocks is available. We collected all plant species that may be eaten by the birds and the fresh feces of Tibetan snowcocks in the foraging habitat on the mountain in Luowa Village, Jianzha County, Qinghai Province from May to August in 2016. The diet was determined by microscopic fecal analysis. The proportion of each identified plant species was calculated. The results showed that all plant organs can be eaten by the birds. Leaves are preferred, followed by stems, flowers, seeds, and roots were rarely eaten. The proportion of plant organs exhibited seasonal variation. The proportion of leaves gradually decreased, that of stems changed little, that of flowers increased obviously in July, and that of fruits (seeds) increased sharply in August (28%). A total of  72 plant species from 24 families were found in snowcocks’ habitat, with Pteridophyta, Bryophyta, and Lichenes being also eaten. Most of the plants (49 species categorized into 19 families) as well as Bryophyta and Lichenes were the food source. Gramineae and Compositae were the main food source, accounting for more than 42% of its diet. Poa pratensis (22.35%) was the main food species of snowcocks, and 20 species including Taraxacum mongolicum were the common food. From May to August, the variation of the proportion of plant species eaten by the birds was obvious. The proportion of Poa pratensis was stabilized at about 20% from May to July, and rose to 30.20% in August, while the proportion of Taraxacum mongolicum generally increased from May to August. The number of plant species eaten by Tibetan snowcocks was relatively stable (35-36 species) from May toAugust and slightly higher (41 species) in July. Food composition of Tibetan snowcocks in different months showed higher similarity (>73%). Shannon diversity index and Pielou evenness index were similar from May to August, but the food niche breadth in August was significantly lower than that in other months. In conclusion, the dietary of Tibetan snowcocks is wide and with a distinct seasonal variation. Our results can provide a basis for the design of artificial feed for a rescue and ex-situ protection of Tibetan snowcocks.
    Vertical distribution and seasonal variations of soil fauna communities in Shanghai Jing’an Sculpture Park.
    JIN Ya-li, YANG Si-qi, XU Shan-shan, XIA Jian-hong, YANG Gang, ZHANG Yun-fei, BU Yun
    2021, 40(2):  480-489.  doi:DOI: 10.13292/j.1000-4890.202102.027
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    The maintenance of urban biodiversity is of great significance to the improvement of urban environment and sustainable development. Soil animals, as a cornerstone and component of biodiversity, are important indicators of urban soil environment. The seasonal dynamics of soil fauna community structure in Shanghai Jing’an Sculpture Park were examined to understand the dynamics of soil animal diversity in urban green spaces and provide scientific reference for biological assessment of soil environment. A total of 2305 individuals of soil animals were captured, belonging to 23 groups, with a total density of 19565 ind·m-2. The dominant groups were Acari and Collembola, accounting for 49.41% and 33.62% of the total abundance, respectively, with an A/C value of 1.5. The common groups were Protura, Diplura, Pauropoda, Diplopoda, Enchytraediae, and Nematoda, accounting for 12.80% of the total abundance. Soil fauna showed obvious surface clustering characteristics. The density of soil animals in the 0-5 cm soil layer was significantly higher than that in the 5-15 cm soil layer (P<0.05). With the soil layer deepened, the Shannon index decreased and the Simpson dominance index increased. The vertical distribution of soil animals showed seasonal variations, with the total density of soil animals being the highest and the Shannon index being the lowest in summer.
    A gradient analysis of urban landscape pattern in Huizhou.
    WU Zi-jing, LI Zhi-jian, ZENG Hui
    2021, 40(2):  490-500.  doi:DOI: 10.13292/j.1000-4890.202102.021
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    We integrated landscape metrics, gradient analysis, and moving window method to analyze the spatial variations of landscape pattern in Huizhou. The radiative gradient zones were set around the downtown by expanding outward at equal distances. Four transects with different directions were set according to the characteristics of the study area. The grain effect analysis of landscape metrics and the land area change evaluation index model were used to determine the appropriate grain for the study area. Considering the anisotropy of landscape pattern, the appropriate spatial extents for different transects were determined by calculating the semivariogram and the corresponding nugget-sill ratio in different directions. The landscape patterns along transects in different directions were analyzed with moving window method. The results showed that: (1) 50 m was an appropriate grain extent for the study area, and the moving window sizes for the four transects were 750, 850, 1350 and 1150 m, respectively. (2) From the center to the periphery, Huizhou can be divided into downtown, agricultural area, urban sub-center area, transition area, and ecological conservation area. (3) Most highly urbanized and exurban areas presented a single landscape component with exclusive advantages. In contrast, the landscape heterogeneity and fragmentation increased in the urban fringe and urban-rural transition zone. (4) Analysis of landscape pattern of different transects can reflect the directional differentiation of the research area, which is an effective means for urban landscape gradient analysis.
    The variation and driving factors of potential evapotranspiration of the forest interior and open land in Yuanjiang dry-hot valley, China.
    WANG Yu-jie, ZHOU Bing-jiang, HUANG Zheng-wen, SUN Rong-qing, YANG Kuan, YANG Lin, CHENG Xi-ping
    2021, 40(2):  501-511. 
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    Evapotranspiration is of great significance for understanding climate change and regional ecological protection. We analyzed the variation and driving factors of potential evapotranspiration (PET) of Yuanjiang savanna ecosystem research station in China through principal component analysis and Pearson’s twosided correlation test. The process of evapotranspiration was interpreted according to the analysis results on forest interior and open land. Results from the analyses on daily PET data from 2015 to 2018 showed that thePET in forest interior was 0.86 mm·d-1 lower than that in open land. The PET in forest interior and open land showed a periodic decrease, with a greater decrease trend in the open land. The drought index of the forest interior and open land in the dry and rainy seasons during 2015-2018 and corresponding years was calculated. Results showed that the drought degree of Yuanjiang savanna ecosystem was alleviated in the study period, with the drought index in forest interior being lower than that in open land. The driving factors of PET in forest interior were air temperature (Ta), surface net radiation (Rn), and soil heat flux at 5 cm below the surface. The driving factors of PET in open land were Ta, soil temperature at 5 cm below the surface, and Rn. The layers of evapotranspiration in forest interior could be clearly divided according to its intensity. The intense layer lay in the middle-upper layer of the shrub forest type and the intensity of evapotranspiration decreased from the middle-upper layer to the lower layer. The layers of evapotranspiration in the open land were relatively mixed, and the layer with the highest intensity of evapotranspiration located in the interface of air and soil.
    Potential geographical distribution and the dominant climatic factors of three commonArtemisia species in China.
    SHI Chao-yi, ZHU Yuan-jun, SA La, WANG Dan-yu, YANG Xiao-hui
    2021, 40(2):  512-524.  doi:DOI: 10.13292/j.1000-4890.202102.017
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    Artemisia tanacetifolia, A. sieversiana and A. argyi are three commonArtemisiaspecies distributed over China. We used MaxEnt model with ROC (receiver operating characteristic curve) for accuracy test to predict the potential distribution of those three Artemisiaspecies under current climate and two future scenarios. The AUC (area under curve values of both training and testing data were above 0.8, indicating good reliability of the prediction. Under the present climatic condition, the areas with the highest occurrence probability of A. tanacetifoliawere mainly distributed in Loess Plateau, Inner Mongolian Plateau, and Northeast China Plain. The most suitable areas of A. sieversiana were distributed in southern Tibet valley, Hengduan Mountains area, Loess Plateau, Inner Mongolian Plateau, and Northeast China Plain. There are two optimal distribution areas of A. argyi: one in the south of Taiwan Island and another consisting of Dabashan Mountain, Wushan Mountain, northern Yunnan-Guizhou Plateau, Loess Plateau and southern Northeast China Plain. Under the scenarios of RCP2.6 and RCP8.5 in 2070,the areas of high suitability of A. tanacetifolia and A. sieversiana will decrease but the optimum distribution area ofA. argyi will increase. Results of the Jackknife test showed that mean annual precipitation was the most effective climatic factor in predictingA. tanacetifolia’s distribution, May precipitation was the most significant factor for A. sieversiana, and August water vapor pressure was the most influencing factor for A. argyi. Our results provide scientific basis for the rational utilization of Artemisia species.

     

    Purification effect of constructed wetland on antibiotic compound pollution and the microbial community response.
    QIN Lan-qian, BAI Shao-yuan, ZHANG Qin, DING Hai-jing, DENG Zhen-gui
    2021, 40(2):  525-533.  doi:DOI: 10.13292/j.1000-4890.202102.006
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    To understand the purification performance and microbial community structureresponse of constructed wetlands to antibiotics additions of fluoroquinolones (FQs), sulfonamides (SFs) and tetracyclines (TCs), we measured the antibiotic contents and microbial community structure in horizontal subsurface flow constructed wetlands with single-layer matrix structure and multi-layer matrix structure (3 and 6 layers) which have been in operation for many years, with solid phase extraction-high performance liquid chromatography and high-throughput sequencing, respectively. We analyzed the removal results of eight antibiotics belonging to three types in wetland systems, the effects on the removal of conventional pollutants, and changes of microbial community structure. The results showed that the constructed wetlands had good removal effects on FQs, sulfathiazole, sulfamethazine and oxytetracycline (>95%), but with relatively poor effects on sulfadiazine and tetracycline (61.9%-66.8%) under the same conditions. The purification effect of multi-layer wetland systems on antibiotics was 3.2% higher than that of single layer wetland system. The addition of antibiotics increased the removal efficiency of COD and NH4+-N by 18.5% and 16.5%, respectively, but decreased that of TP by 28.6%. After the addition of FQs, SFs, and TCs, mean Shannon index in the three wetland systems decreased from 5.80 to4.66, while mean Simpson index increased from 0.017 to 0.063. Before and after the addition of antibiotics, the main dominant phyla (Proteobacteria and Bacteroidetes) remained unchanged, while the primary and secondary positions of the other dominant phyla (Chloroflexi, Firmicutes, Verrucomicrobia, and Acidobacteria) changed. There were obvious changes in the structure of dominant genera. The abundance of denitrifying bacteria Acinetobacter, Aquabacterium and Pseudomonas were significantly increased, replacing the phosphorusremoving bacteria Dechloromonas and Flavobacterium as the main dominant genera.
    Forming mechanisms and ecological function of wood-decaying fungal community in forest ecosystem.#br#
    WEI Yu-lian
    2021, 40(2):  534-543.  doi:DOI: 10.13292/j.1000-4890.202102.001
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    Deadwood is an important component of forests that provides habitat and contributes to nutrient cycles as well as carbon and water storage. Given the importance of deadwood decomposition in nutrient cycling, soil formation, and ecosystem carbon budget, it is received increasing attention from ecologists, pathologists and forest managers. Wooddecaying fungal communities play a crucial role in driving ecosystem material cycling by producing various degrading enzymes. The composition of wooddecaying fungal community is affected by many factors, including environmental factors (precipitation, latitude, light, temperature, and humidity) and the characters of host deadwood (chemical composition, physical structure, diameter, volume, and decay degree). They drive the distribution and growth of fungal species and consequently fungal community composition. The fungi could manipulate microbial community in their surroundings. The species forming large networks of mycelial cords can manipulate the bacterial community more effectually. Bacteria have an indirect effect on decomposition rates by consuming the breakdown products of fungal enzymatic activity, thus influencing the dynamics of fungal community. As two main groups of deadwood decomposition, wood-decaying fungi and saprophytic invertebrates interact with each other, showing both inhibitory and facilitative effects. Some soil fungi can colonize deadwood through hyphae growth. The biggest disturbance to the composition of wooddecaying fungi community comes from the deforestation and utilization of forests. The removal of fallen wood directly leads to the loss of the growth substance, which makes many species being endangered and the fungal community composition being simple and the function being relatively simplified. During deadwood decomposition, whiterot fungi degrade lignin by producing peroxidase and laccase, while brown-rot fungi can degrade hemicellulose and cellulose effectively. The activity and type of degrading enzymes affect wood decay rate and nutrient content. Fungal hyphae have an important role in nutrient absorption and transfer. The functional traits of wooddecaying fungi can reflect the adaptation of species to environmental conditions and help to understand the mechanisms underlying the aggregation of fungal communities in different environment. Since wood-decaying fungi have multiple functions in forests, it is necessary to understand the formation of wood-decaying fungal community and its role in decomposition, which provides insights into nutrient cycling and biodiversity conservation.
    A review on methodology for the measurement of personality in fish.
    LI Wu-xin, SUN Chun-yan, ZENG Ling-qing
    2021, 40(2):  544-558.  doi:DOI: 10.13292/j.1000-4890.202102.031
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    Animal personality refers to the consistent individual differences in behavioral traits across temporal and spatial scales. The research history of fish personality has been more than 50 years. There were great differences in the methods of measuring fish personality in different periods and studies, without a normative methodology for quantifying personality in fish. We suggest that it is necessary to pay attention to conventional measurement methods of fish personality, and to understand the definition of personality and its ecological significance, and to standardize the conventional experimental methods of fish personality. In this review, we focused on the narrow sense of personality such as boldness, exploration, activity, aggressiveness as well as sociability. We summarized the measurement methods of personality in order to standardize conventional measurement methods and precautions of fish personality. Finally, we discussed deficiencies of the measurements of fish personality in literature.
    Research progress on characteristics and applications of endogenous cellulase in apple snail.
    LI Meng-ting, LIU Jin-ling, ZHAO Ben-liang, DENG Xiao-yu, CHEN Hui-ying, TANG Yi-jie
    2021, 40(2):  559-567.  doi:DOI: 10.13292/j.1000-4890.202102.026
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    Cellulase can efficiently degrade cellulose to produce monosaccharides, with valuable potential in textile, paper, food, feed and other industries. Recently, animal-originated cellulase has drawn widespread attention due to its excellent ability in cellulose biodegradation. As a noxious invasive gastropod that has colonized South China for forty years, the apple snail  has caused severe damage to rice production and wetland biodiversity. The strong digestive ability of apple snail on plants is closely related to the endogenous cellulase. We carried out a comprehensive analysis on the endogenous cellulase in apple snail by summarizing coding characteristics, factors determining endogenous cellulose activity, gene expression and utilization. There were significant differences in molecular weight, gene length, open reading frame length, homology of the endogenous cellulaseencoding gene of apple snails. Environmental factors, including pH, temperature, metal ions, anions and chelating agents, greatly affected enzyme activity. Genetic engineering and optimized strain cultivation could improve the production efficiency of endogenous cellulase in apple snails. The endogenous cellulase of apple snails helped improve biological efficiency and yield of edible fungi, increase the utilization rate of animal feed, and enhance fruit and vegetable juice extraction. The expression of endogenous cellulase gene in beer yeast helped increase ethanol production. According to the problems in applying endogenous cellulase of apple snail, we put forward countermeasures for accelerating the utilization of the endogenous cellulase of apple snail and suggestions for emphasizing the research on the endogenous cellulase from other Pomacea snails.
    Suggestions on the development of healthy shrimp culture under ecological framework.
    YU Dao-de, SONG Jing-jing, YE Hai-bin, WANG You-hong, WANG Xiao-lu, LIU Hong-jun
    2021, 40(2):  568-576.  doi:DOI: 10.13292/j.1000-4890.202102.013
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    With the development of shrimp aquaculture, the frequent occurrence of diseases and water pollution are becoming increasingly prominent. This contradiction is made more difficult by the diversification of shrimp species and aquaculture systems. We reviewed the history of diseases associated with the development of shrimp industry in China during the past 50 years, and re-examined the occurrence and evolution of shrimp pathogens and their relationships with the immune systems of shrimps from an ecological perspective. Some suggestions were put forward, such as avoiding drug abuse, giving prominence to prevention prior to control, paying attention to shrimp breeding, and carrying out shrimp culture in an ecosystem approach. In the future, we should pay more attention to ecosystem health and apply the concept of ‘One Health’ to shrimp aquaculture, with the aim to realize the healthy and sustainable aquaculture.
    Effects of spatial scales on topographic heterogeneity-species richness relationships: Grain and extent.
    LIANG Xiao-yu, GU Yuan-yang, LIU Chang, XING Shao-hua
    2021, 40(2):  577-585.  doi:DOI: 10.13292/j.1000-4890.202102.014
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    Spatial scales can influence our perception of ecological patterns and processes. There was no consensus on the mechanisms underlying the spatial patterns of species richness, largely due to the effects of spatial scales on the explanatory power of different environmental factors and their relative importance in shaping species richness patterns. Topographic heterogeneity is one of the most important factors shaping geographical patterns of species richness. In this review, we discussed the effects of spatial grain and extent on the relationship between topographic heterogeneity and species richness. Although the scaledependence in spatial species richness gradients has become increasingly recognized, it remains unclear how the strength of the relationship between topographic heterogeneity and species richness changes with varying scales of grain and extent. Current studies failed to provide a more complete multiscale picture of spatial patterns in species richness and their drivers. A multiscale perspective with regard to both grain size andextent would shed new light on the studies of topographic heterogeneity-species richness relationships. Further comparative research on geographical patterns of species richness across multiple spatial scales using sound statistical methods and models would improve our understanding of the relative role of topographic heterogeneity at different scales.

     

    Review on the effect of offshore wind farms on macrobenthos.
    ZHAN Xiao-fang, MA Li, LU Zhi-qiang
    2021, 40(2):  586-592.  doi:DOI: 10.13292/j.1000-4890.202102.025
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    The number of offshore wind farm (OWF), as renewable energy device, has increased rapidly around the world. The construction and operation of OWF would potentially affect benthic environment. We reviewed the researches related to the impacts of OWF on macrobenthos, including provision of reef habitat, biodiversity change, protection of the seabed from trawling, and enhancement of ecological connectivity. Future research should focus on the impacts of OWF on the succession of macrobenthic communities in the long term and its potential ecological effects on the marine benthic environment. Knowledge sharing and information exchange among industry, government, and scientific research department will contribute to comprehensive and indepth understanding of the impacts of OWF on marine ecosystems.
    Assessment on the importance of ecosystem services along the Transmission Line of Tibet Networking Project.
    CAI De-feng, ZHANG Yang-jian, CONG Nan, YIN Guo-dong, WANG Li, ZHANG Ming-xun, ZU Jia-xing, ZHOU Quan, CHEN Ning, LIU Yao-jie, LAN Jian-jun, CAI Shao-rong, ZHANG Ge
    2021, 40(2):  593-603.  doi:DOI: 10.13292/j.1000-4890.202102.003
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    Evaluating ecosystem services along the line of power grid projects is critical for avoiding or reducing the negative impacts of grid construction on ecosystems. Based on remote sensing and GIS technologies, we selected four kinds of primary ecosystem services (i.e., water conservation, soil and water conservation, windbreak and sediment conservation, and biodiversity protection) to evaluate the importance of ecosystem services in southeastern Tibet. We further evaluated the importance of ecosystem services for the influenced areas of each bid section of the Tibet Networking Project. The results showed that the pattern of the importance of ecosystem services over southeastern Tibet was high in east and west parts and low in central region. The area with extremely important service was 74843 km2, accounting for 18.47% of the total area. This area was mainly distributed in the forest region of southeastern Tibet, containing area along and east to Lancang River, area along Yarlung Zangbo River, and the southern part of Cuona and Motuo counties. The sections located in east and west terminals showed a relatively high importance of ecosystem services. Measures for ecological and environmental protection should therefore beadopted by considering the distribution of primary ecosystem services. This study could provide the ecological criterion and scientific reference for the design and construction of other similar transmission projects.
    Analysis on dust retention capability of greening tree species surrounding coal-fired power plant based on leaf surface micro-structure.
    LI Shi-yao, NIU Yu-bin, FAN Jin, YU Hai-long, HUANG Ju-ying
    2021, 40(2):  604-614.  doi:DOI: 10.13292/j.1000-4890.202102.018
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    The dust retention capacity of greening tree species is closely related to leaf surface micro-structure. We measured the dust retention quantities of the leaves from five broad-leaved greening tree species around a thermal power plant in Ningdong Energy Industrial Base, using the method of washing and filtering. The leaf surface microstructure was observed by scanning electron microscopy. The relationship between leaf surface micro-structure and dust retention capability was analyzed. Results showed that there were significant differences in dust retention capability of leaves among the five species, with a rank of Rhus typhina>Ailanthus altissima>Ulmus pumila>Maackia amurensis>Fraxinus chinensis. Rhus typhina and Ailanthus altissima, with combined characteristics of epidermis trichome, stomata, gap and roughness, had higher dust retention capability. According to the analysis of particle size and composition of dust detained on the leaves, some tree species showed selective retention and adsorption. For example, Fraxinus chinensis as a stomatal adsorption type tree species had stronger capability of PM2.5 adsorption, while Rhus typhina and Ailanthus altissima, due to the combined characteristics of epidermis tomentum, stomata, gap and roughness, had a wider particle size adsorption range. Based on the results of energy dispersive spectrometer analysis, dust derived from soil was identified on leaves broadly, while organic pollutants derived from anthropogenic sources were also found on the tree species with epidermis tomentum. Therefore, according to the local air pollution type, tree species with leaf surface micro-structures being beneficial to dust retention should be chosen for greening in the energy industrial zone.