Table of Content

10 January 2022, Volume 41 Issue 1

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Species diversity and soil physicochemical properties of different communities in Bifengxia evergreen broad-leaved forest.

ZHOU Run-hui, SU Tian-cheng, YU Jing, XIANG Lin, CHEN Cong-lin, ZHANG Han-wen, LI Jing, HAO Jian-feng

2022, 41(1):  1-8.  doi:10.13292/j.1000-4890.202201.019

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To better understand species diversity and soil physicochemical properties of evergreen broad-leaved forests in Bifengxia scenic spot, Sichuan Province, and thus put forward a reliable method for forest management and biodiversity protection, we used typical sampling method to investigate 27 plots. Through clustering and sorting, the plots were classified objectively. On this basis, we explored species diversity and soil physicochemical properties of different community types. Six types were classified when Bray-Curtis distance was 0.53, i.e., Symplocos sumuntia-Castanopsis fargesii community (Ⅰ), Symplocos sumuntia-Cyclobalanopsis glauca community (Ⅱ), Schima superba-Symplocos sumuntiacommunity (Ⅲ), Schima superba-Elaeocarpus japonicus community (Ⅳ), Castanopsis fargesii-Cunninghamia lanceolatacommunity (Ⅴ), and Castanopsis fargesii-Quercus serrata community (Ⅵ). The dominant species of each community was significantly different. Type Ⅲ had the highest diversity level; Types Ⅱ, Ⅵ and Ⅴ were in the middle; Types Ⅰ and Ⅳ had low diversity level. The soil in this area was relatively acidic and had ample water content. Soil total nitrogen, total phosphorus, total potassium and organic matter contents were the lowest in type Ⅲ. The nutrient contents of types Ⅰ and Ⅳ were in the middle, and type Ⅰ had the highest total phosphorus content. Types II and V had the highest total nitrogen, available phosphorus, total potassium, and available potassium contents. The results of redundancy analysis showed that organic matter, total nitrogen and soil water content were the main factors affecting species diversity of the community, which were significantly (P<0.05) or extremely significant (P<0.01) negatively correlated with each diversity index. In conclusion, species diversity of Types Ⅲ and Ⅵ were ranked first and second, respectively, but these diversity-rich vegetation consumed a lot of nutrients, which made the soil nutrient-deficient. The diversity level of Types Ⅰ and Ⅳ were low, and the community development trend was not good. Types Ⅱ and Ⅴhad a moderate level of diversity, and their soil fertility conservation were the best, indicating that they had the potential for the succession to climax community. We suggested that appropriate artificial measures should be taken to improve the ecological function and disturbance-resisting ability of stands.

Population structure characteristics and health evaluation of Armeniaca vulgaris Lam.

YANG Qi-xiang, LIU Li-qiang, QIN Wei, DIAO Yong-qiang, ZHAO Zhong-jing, WU Ren-qi-mi-ge, ZHANG Bo

2022, 41(1):  9-17.  doi:10.13292/j.1000-4890.202201.017

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We explored the population structure and survival status of Armeniaca vulgaris, and evaluated the health status and renewal ability of A. vulgaris, in order to provide a theoretical basis for its protection and restoration. A total of 22 plots were set up in four A. vulgaris populations in Xinghuagou (Tuergen Town, Xinyuan County), Yilegedaigou (Tastobe Town, Gongliu County), Daxigou (Daxigou Town, Huocheng County) and Mohegou (Kuerdening Town, Gongliu County) in Xinjiang. We investigated the non-spatial structure (species composition, DBH (DBH≥5 cm), tree height, crown width, canopy density, tree density) and spatial structure (angle scale, mixing degree, size ratio) of each A. vulgaris population. The health status of A. vulgaris was evaluated based on the population structure. The proportion of A. vulgaris in four populations of Xinghuagou, Mohegou, Yilegedaigou and Daxigou was 100%, 73.91%, 97.70% and 36.17%, respectively. The stand density of each population was 565, 322, 435, 575 plants·hm^-2, and the canopy density was 0.92, 0.55, 0.82, 0.78, respectively. The stand density was large and the canopy density was high. The average tree height of four populations was 6.75, 6.48, 6.47, 6.70 m, and the average crown width was 6.00, 5.26, 5.01, 6.20 m, respectively. There was no significant difference in tree height among the four populations, and crown width was large. There was cross-overlapping between tree crowns, with large extent of overlap. The age-class structure of A. vulgaris was basically spindle-shaped, and the overall structure wasunstable. It was mainly composed of 83.60% of mature, middle-aged, and old individuals, while it seriously lacked young individuals (accounting for 10.16%). The average size ratios of Xinghuagou, Mohegou and Yilegedaigou populations were 0.46, 0.45 and 0.49, respectively, with a middle state of DBH growth. The average size ratio of Daxigou population was 0.63, with an inferior state of DBH growth. The mean mingling degree ofA. vulgaris in four populations was 0, 0.05, 0.20 and 0.49, respectively, suggesting that A. vulgaris can survive in pure population and that it can also survive with other wild fruit tree species. The average angular scales of these four populations were 0.39, 0.37, 0.33 and 0.40, respectively, indicating a uniform horizontal distribution. The weighted composite index of Xinghuagou, Mohegou, Yilegedaigou and Daxigou populations was 0.48, 0.45, 0.30 and 0.52, and the weighted sum index was 0.37, 0.48, 0.36 and 0.53,respectively. The health status of A. vulgaris populations in Daxigou and Mohegou was at moderate level. The health grade of Xinghuagou population was moderate by weighted comprehensive index, and was poor by weighted sum index, being moderate to lower by the comprehensive evaluation. The health grade of A. vulgaris population in Yilegedaigou was poor. Based on the structure characteristics and viability of A. vulgaris populations, the current health status of A. vulgaris populations in Xinjiang was at moderate to lower level. The A. vulgaris populations should be urgently protected and restored. This study evaluated the health status A. vulgaris populations from the appearance traits, which can lay a foundation for further study of the survival of A. vulgaris.

Response of community characteristics and representative plant living state to grassland degradation in alpine meadow of Qinghai-Tibet Plateau.

LUO Fang-lin, ZHANG Fa-wei, WANG Chun-yu, ZHANG Guang-ru, LI Ying-nian

2022, 41(1):  18-24.  doi:10.13292/j.1000-4890.202201.004

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The living state of representative plants and plant community is one of the important indicators for grassland degradation. With a gradient of nondegraded, lightly degraded, moderately degraded, heavily degraded, and extremely degraded alpine meadows in Maqin County, Guoluo Prefecture, Qinghai Province, we analyzed the responses of plant communities, aboveground traits of representative plants and vegetation living state to degradation. Species composition transitioned from Gramineae and Cyperaceae to weeds with intensified degradation. The Shannon diversity index, Simpson dominance index, and Pielou evenness index changed steadily first and then decreased. The community average height and Patrick abundance increased first and then decreased. The total coverage of plant community decreased sequentially. The values of community characteristic indicators were the lowest when communities were extremely degraded (P<0.05). Compared with the lightly degraded plots, plant height of moderately degraded plots, heavily degraded plots, and extremely degraded plots decreased by 6.8%, 36.8%, and 31.6% respectively (P<0.05). The living state index of Kobresia pygmaea gradually decreased. The living state index of Elymus nutans was the highest in moderate degradation. The living state index of Poa orinosa was the highest in light degradation. The living state index of Lancea tibetica was the highest in heavy degradation, while Ligularia virgaurea grew best in the extremely degraded plot. Our results indicated that the degradation of alpine meadows resulted in the changes of community characteristics, the decrease of biodiversity, the decline of living state and dominant position of Cyperaceae and Gramineae, as well as the gradual increase of living state and dominant position of weeds.

The distribution pattern of herbaceous plant diversity in urban forests along an urban-rural gradient in Shanghai.

XU Shan-shan, YAN Jing, PENG Zhi, ZHANG Wen-wen, WANG Jun-fu, ZHANG Yun-fei, HAN Yu-jie

2022, 41(1):  25-32.  doi:10.13292/j.1000-4890.202201.027

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Understory herbaceous plants are a major conservation layer for the biodiversity of urban forest ecosystems. Due to their high plasticity and sensitivity to disturbance, herbaceous plants can effectively indicate the adaptation strategy of urban vegetation to urbanization. In this study, we surveyed 398 plots in 16 sites of woodland located along a gradient of central city area, suburb area, and rural area in Shanghai, and analyzed the flora characteristics and diversity pattern of herbaceous plants in urban forests. A total of 144 herbaceous species were recorded, which belonged to 47 families and 118 genera. Among them, 74 species of perennial herbs were recorded, contributing over half of the total species (51.39%). The distribution type of genus and species covered 18 and 12 geographical distribution types and subtypes, respectively, and most were temperate and tropic species. There were 28 alien species, accounting for almost 20% of the total. Both specie richness and diversity index of herbaceous plants were deceased firstly and then increased along the urban-rural gradient. Species composition in central city sharply contrasted to that in suburban sites, but was quite similar to that in rural sites. Our results clarified the distribution pattern and variation of the diversity of herbaceous plants along urban-rural gradient in Shanghai, and provide a theoretical basis for researches on the interaction between urbanization and urban forest and scientific reference for the management department to makepolicy.

Effects of species diversity and environmental factors on the stability of the invasive Alternanthera philoxeroides communities

WU Hao, JIA Shao-qi, ZHU Ya-xing

2022, 41(1):  33-41.  doi:10.13292/j.1000-4890.202201.014

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To explore the mechanism underlying community stability of the invasive plant Alternanthera philoxeroides, we set up 73 plots (39 terrestrial and 34 aquatic) with a size of 10 m×10 m each in the latitudinal gradient from 21°N to 37°N in China. We calculated the Godron community stability coordinates and four α-species diversity indices, and measured seven environmental factors (longitude, latitude, elevation, NH₄⁺-N, NO₃-N, mean annual temperature, and mean annual precipitation). We used regression analysis and redundancy analysis to examine the effects of species diversity and heterogeneous habitats on the stability of invaded communities. The results showed that: (1) A total of 169 plant species were recorded in the terrestrial communities, belonging to 55 families and 147 genera, and the dominant species accompanying A. philoxeroideswere Digitaria Sanguinalis, Echinochloa crusgalli,Bidens pilosa andEleusine indica. A total of 107 plant species were recorded in the aquatic communities, belonging to 49 families and 92 genera, and the dominant accompanying species werePaspalum bipinnata, Ceratopteris thalictroides, E. crusgalliand Bidens pilosa. (2) Results of regression analysis showed that the stability of terrestrial communities decreased with the increases of Simpson diversity index, Shannon diversity index, and Pielou evenness index, whereas the stability of aquatic communities decreased with the increases of Pielou index. There was a unimodal change with the increases of Patrick richness index. (3) Results of regression analysis and redundancy analysis showed that the dominant environmental factors determining the stability of A. philoxeroides community in terrestrial and aquatic habitats were longitude, latitude, mean annual temperature, and mean annual precipitation. Among them, terrestrial community stability increased with the increases of longitude and latitude, but decreased with the increases of mean annual temperature and mean annual precipitation. However, the change ofaquatic community stability along the environmental gradient was opposite to that of terrestrial communities. These results indicated that the responses of A. philoxeroides community stability to species diversity and heterogeneous environments differ greatly between terrestrial and aquatic habitats. Under the rapid global environmental changes, more attentions should be paid to the monitoring of terrestrial A. philoxeroides community dynamics in high latitudes as well as aquatic A. philoxeroides community in heavy rainfall areas.

Effects of Spartina alterniflora invasion on morphological characteristics of tidal creeks and plant community distribution in the Yellow River Estuary.

YU Dong-xue, HAN Guang-xuan, WANG Xiao-jie, ZHANG Bao-hua

2022, 41(1):  42-49.  doi:10.13292/j.1000-4890.202201.003

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Large-scale invasion of Spartina alterniflora on coastal wetlands has a great impact on the morphological characteristics of tidal creeks and the succession of plant communities. Based on the remote sensing images from 2008 to 2020, we analyzed the evolution characteristics of S. alterniflora invasion and its effect on the morphological characteristics and plant community distribution of tidal flats in the Yellow River Estuary by using 3S technology, regression analysis, and statistical analysis. The results showed that the area of S. alterniflora had increased rapidly in the Yellow River Estuary since 2008, with a growth rate of 4.47 km²·a^-1. By 2020, the distribution area of S. alterniflora accounted for 26% of the estuary area. With the expansion of S. alterniflora, the areas of Phragmites australis and Suaeda salsa were decreased gradually, with arate of 0.72 and 0.39 km²·a^-1, respectively. In the typical tidal flat area of the Yellow River Estuary, the length and density of tidal creeks were decreased by 8.12 km and 0.24 km·km^-2, respectively. The distribution area of P. australis and S. salsa, as well as the length and density of tidal creeks were significantly negatively correlated with the distribution area of S. alterniflora.

Characteristics of phytoplankton functional groups and their environmental drivers in Xiaowan Reservoir area of Lancang River during the summer of 2017-2019.

PENG Meng, WU Jia-wei, LI Luo-xin, TAN Feng-xia, HE Qiu-jie, WU Ze-cheng, CHAI Yi

2022, 41(1):  50-57.  doi:10.13292/j.1000-4890.202201.028

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To explore the characteristics and key driving factors of phytoplankton functional groups in Xiaowan Reservoir area of Lancang River, a survey was conducted in August during 2017 to 2019. Data were analyzed by using functional groups classification, redundancy analysis and Pearson correlation analysis. A total of 71 species of phytoplankton from 7 phyla were identified, among which chlorophyta were the most phytoplankton species (34 species, accounting for 47.89%). The 71 species were classified into 23 functional groups according to functional group classification. The top 5 important functional groups were identified according to the dominance index(>0.2). The identities of important functional groups showed interannual variations. Results of the correlation analysis between functional groups and environmental factors showed that nitrate and ammonium were the main limiting factors in Xiaowan Reservoir, and the reservoir area was limited by nitrogen from 2017 to 2019. Results of comprehensive analysis showed that the characteristics of phytoplankton functional groups were consistent with the changes of water environmental factors. Xiaowan Reservoir was generally at the state of moderate eutrophication to eutrophication. The habitat characteristics of Xiaowan Reservoir area could be well indicated by phytoplankton functional groups.

Effects of duck varieties on the growth characteristics of rice in rice-duck symbiosis system.

ZHANG Yin, YU Zheng-jun, LYU Guang-dong, WANG Ren, CHEN Can, HUANG Huang, CHEN Zhi-feng

2022, 41(1):  58-65.  doi:10.13292/j.1000-4890.202201.030

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The differences of duck varieties may affect the growth characteristics of rice in rice-duck symbiosis system. We selected Youxian partridge duck (SY), Muscovy duck (YY) and mallard (LTY) to explore the effects of different duck varieties on rice growth characteristics, with the conventional rice monoculture as the control (CK). A field plot experiment following randomized block design was used to study the changes of rice root traits, stem traits, leaf traits, and rice yield. The results showed that the YY and LTY treatments had certain negative effects on rice root, stem and leaf traits in the early growth stage of rice (except plant height), resulting in significantly lower growth characteristics compared with the CK. The YY and LTY treatments slowed the aging and decline of root, stem, and leaf, made those traits significantly better than that of CK in the late growth stage of rice, finally increased rice yield by increasing the effective panicles and setting rate. Moreover, the YY and LTY treatments significantly reduced total grain number per panicle, but did not affect the number of filled grains per panicle and thousand-grain weight. Compared with the CK, SY treatment significantly increased leaf dry weight only at full heading stage, and did not affect other agronomic traits at other stages. Our results could provide theoretical basis for the choice of duck varieties in riceduck symbiosis system.

Effects of combined organic fertilizer and chemical fertilizer application on soil biological characteristics, yield, and quality of Chinese cabbage with different maturity periods.

WANG Lei, GAO Fang-sheng, CAO Bi-li, LUAN Zhao-shui, WANG Ming-you, WANG Wei

2022, 41(1):  66-72.  doi:10.13292/j.1000-4890.202201.032

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We examined the changes in soil enzyme activities and cultivable microorganisms, as well as yield and quality of Chinese cabbage with different maturity periods (early maturing and late maturing) under four fertilization treatments with different proportions of chemical fertilizer nitrogen (urea) and organic fertilizer nitrogen (organic manure). The results showed that, for the early-maturing variety ‘Degao 16’, combined application of 1/2 organic manure and inorganic fertilizer (T₂) had higher activities of invertase, urease, and catalase, higher soil organic matter content, and more soil cultivable microorganisms at both the rosette stage and head-tightening stage. The late-maturing variety ‘Qinghua 76’ performed well with T2 treatment at the rosette stage. At the headtightening stage, ‘Qinghua 76’ under combined application of 1/4 organic manure and inorganic fertilizer (T₁) had higher soil enzyme activity, organic matter content and the total amount of soil cultivable bacteria, actinomycetes and cultivable microorganisms than other treatments and CK. Meanwhile, the early-maturing variety ‘Degao 16’ under T₂ treatment had 10.0% more yield than under single chemical fertilizer application. The late-maturing variety ‘Qinghua 76’ under T₂ treatment performed better, with an 8.9% enhancement of yield as compared to the treatment with chemical fertilizer alone. Treatments T₁ and T₂ significantly increased the contents of soluble protein, soluble sugar, and vitamin C in Chinese cabbage, and reduced the contents of crude fiber and nitrate. Therefore, reducing the application of chemical fertilizers but applying bio-organic fertilizers at an appropriate ratio regulated the quantity and community structure of soil microorganisms, increased soil enzyme activity, and promoted plant growth, thereby enhancing Chinese cabbage yield and quality. The early-maturing variety ‘Degao 16’ Chinese cabbage combined with 1/2 bio-organic fertilizer and the late-maturing variety ‘Qinghua 76’ combined with 1/4 bio-organic fertilizer had the best performance.

Variation of soil organic nitrogen fractions in maize field during growing season and its response to current year and long-term straw returning.

DONG Shu-han, LYU Hui-jie, ZHOU Feng, ZHANG Xiao-chen, HE Hong-bo, ZHANG Xu-dong, ZHANG Wei

2022, 41(1):  73-80. 

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The analysis of the variation of soil organic nitrogen fractions in growing season and its response to current year and long-term straw returning could provide scientific basis for reasonable regulation of soil organic nitrogen pool and the improvement of soil fertility. A field plot experiment with two treatments was conducted at the National Field Observation and Research Station of Shenyang Agroecosystems, i.e., single application of nitrogen fertilizer and straw returning combined with nitrogen fertilizer. Soil samples were collected at before-seeding, jointing, silking, filling, and maturity stages. Bremner method was used to classify soil organic nitrogen fractions. The results showed that each of the organic nitrogen fractions in the soil showed obvious dynamic patterns in the whole growing season of maize. Hydrolyzable ammonium content increased firstly and then decreased, indicating that it may act as a temporary pool during soil nitrogen transformation. Amino acid nitrogen did not vary significantly across the growing season. Amino sugar nitrogen was significantly lower in the late growing season than that in the early growing season. Hydrolyzable unknown nitrogen increased and then decreased with high activity across the growing season. Compared with single nitrogen treatment, straw returning increased the contents of soil total nitrogen and hydrolyzed nitrogen at the end of the growing season and in the long term, increased the proportion of hydrolyzed nitrogen to total nitrogen, and decreased the proportion of no hydrolyzed nitrogen to total nitrogen by 7.2% and 3.8% in the current season and long term, respectively. The results indicated that straw returning could not only improve soil nitrogen availability, but also improve the capability of soil nitrogen storage and supply.

Characteristics of climate change during the growth period of winter wheat and its influence on yield in South Shanxi Province.

ZHONG Rong, REN Yong-kang, WANG Pei-ru, LIN Wen, REN Ai-xia, SUN Min, GAO Zhi-qiang, XU Jun-ming

2022, 41(1):  81-89.  doi:10.13292/j.1000-4890.202201.034

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Clarifying the characteristics of climate change and its impacts on wheat yield will provide a theoretical basis for the formulation of agricultural adaptation plans to climate change. Here, we analyzed the changes of precipitation, temperature, sunshine duration, potential evapotranspiration,  aridity index, and their impacts on growth stage and yield of winter wheat in Linfen and Yuncheng from 1957 to 2015, two main wheat production areas in Southern Shanxi. The results showed that a downward trend of annual precipitation and sunshine duration was found during wheat growth stage from 1957 to 2015. Precipitation during the growth period of winter wheat showed a decreasing trend before winter, an increasing trend from wintering stage to jointing stage, and a decreasing trend from jointing stage to anthesis stage. The annual mean daily temperature, mean daily maximum temperature, and mean daily minimum temperature in the two places increased with a rate of 0.24-0.37, 0.16-0.18, and 0.37-0.60 ℃·(10 a)^-1, respectively. The accumulated temperature of winter wheat in each growth period showed a significant upward trend. Among them, the effective accumulated temperature of Linfen and Yuncheng during the growth period of ≥3 ℃ increased with a rate of 76.94 and 63.10 ℃·(10 a)^-1, respectively; the active accumulated temperature (≥10 ℃) increased at a rate of 74.35 and 57.20℃·(10 a)^-1, respectively. The potential evapotranspiration and aridity index of Linfen weredecreasing, while that of Yuncheng was increasing. The duration of winter wheat wintering stage in Linfen and Yuncheng decreased with a rate of 4.56 and 3.09 d·(10 a)^-1, respectively. The yield of winter wheat in Linfen and Yuncheng increased at the rate of 645.4 and 528.8 kg·hm^-2·(10 a)^-1, respectively. Results of correlation analysis between yield and various meteorological factors showed that winter wheat yield was significantly correlated with accumulated temperature, annual daily mean temperature, mean daily minimum temperature, sunshine duration during growth period, and precipitation during wintering stage to joining stage. Yield was significantly positively correlated with mean daily maximum temperature, and was significantly or extremely significantly negatively correlated with potential evapotranspiration and aridity index in Linfen. In short, climate in Southern Shanxi is becoming warm and dry. Current climate change is generally beneficial to wheat production. To further reduce the adverse effects of climate change, wheat varieties with long growth period and weak winter characteristics can be introduced and cultivated.

Soil fungi community structure in Mu Us Sandy Land with different afforestation durations by aerial seeding.

GONG Xiao-qian, YAO Lin-jie, ZHANG Jia-ning, LIU Qing-fu, SU Ni-er, YAN Yong-zhi, LI Feng-shi, WANG Xiao-jiang, ZHANG Qing

2022, 41(1):  90-97.  doi:10.13292/j.1000-4890.202201.033

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We used highthroughput sequencing technology to assess the effects of multi-year aerial seeding (0, 6, 16, 26, and 36 years) on soil fungi community structure and diversity in the Mu Us Sandy Land, and examined the effects of soil factors on soil fungi community structure. The results showed that soil fungi community structure changed with aerial seeding duration. Except for the Simpson diversity index, fungi alpha diversity index, the number of phylum and genus,and the abundance of unique OTUs showed an initial decrease followed by an increasing trend. Principal coordinates analysis showed variations in soil fungi community composition at different aerial seeding years, with increasing differences along with the extension of aerial seeding duration. Results of Pearson correlation analysis showed that nitrate and available phosphorus concentrations were the main soil factors affecting the distribution of soil fungi. We conclude that aerial seeding afforestation improves soil fungi community structure and diversity by enhancing theemergence of dominant fungi groups in the Mu Us Sandy Land. Overall, our results provide support for the beneficial role of aerial seeding afforestation in vegetation restoration in the Mu Us Sandy Land.

Responses of soil respiration to warming and cooling at different elevations of Wuyi Mountain.

HUANG Shi-de

2022, 41(1):  98-107.  doi:10.13292/j.1000-4890.202201.012

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Subtropical areas are subjected to rapid climatic change owing to anthropogenic activities, which could potentially affect soil respiration. In this study, a coniferous forest (CF) at 1442 m and an evergreen broad-leaved forest (EBF) at 645 m were selected as research objects in the Wuyishan National Park, Fujian Province, China. The effects of simulated warming (soil monoliths transferred from CF to EBF) and cooling (soil monoliths transferred from EBF to CF) on soil carbon processes were explored using a reciprocal soil monoliths translocation experiment. The microclimate, soil respiration, soil organic carbon, soil total nitrogen and soil labile organic carbon were measured for in situ and transferred treatments at both elevations. The results showed that soils experienced warming had higher temperature and lower moisture. In contrast, soils experienced cooling had lower temperature and higher moisture. Simulated warming substantially-increased soil respiration by 99.6% and significantly decreased temperature sensitivity (Q₁₀) compared with the CF incubated in situ. Simulated cooling substantially reduced soil respiration by 43.3% and increased Q₁₀ compared with the EBF incubatedin situ. Soil temperature was the factor driving changes in soil respiration, whereas soil moisture had no relationship with soil respiration (P>0.05). At the end of the experiment, soil organic carbon contents of the EBF and CF were increased by 12% and 10%, respectively, which might be related to the decomposition of dead roots and leaf litter. The soil organic carbon content decreased slightly under both the warming and cooling treatments, which could be explained by the differences in intensity of soil respiration. At the end of the experiment, warming reduced soil microbial biomass carbon, but increased dissolved organic carbon. In contrast, cooling increased soil microbial biomass carbon and decreased dissolved organic carbon, indicating that soil labile organic C may not respond equally to warming and cooling. Therefore, the responses of soil respiration to warming and cooling should be considered for the construction of climate change response models when both warming and cooling are involved in the climate change.

Effects of fertilization and straw return on nutrient distribution along soil profile in black soil croplands.

SONG Jia-li, WANG Hong-yan, ZHANG Shu-xiang, PENG Chang, LU Cai-yan, CHI Guang-yu, CHEN Xin

2022, 41(1):  108-115.  doi:10.13292/j.1000-4890.202201.010

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An in situ field experiment combined with the brilliant blue staining tracer was conducted to study the distribution of soil nutrients and its response mechanism to fertilization and straw return under no fertilization (CK), conventional chemical fertilizer (T₁), NPK reduction plus straw return (T₂), and NPK reduction with straw return and organic manure (T₃) in maize croplands in black soil region of Northeast China. The results showed that compared with CK, the treatments with fertilization and/or straw return significantly increased maize yield. There was no significant difference in total nutrient content of plough layer among different treatments. Treatment T₁ increased soil nitrate content of at the 40-80 cm layer, while  T₃ increased available K content of in 0-100 cm soil layers and nitrate content in 0-40 cm and 80-100 cm soil layers. There was no significant difference in soil matrix flow among different treatments. Organic manure and straw return affected soil preferential flow, but without difference among the three fertilization treatments. Application of organic manure can promote the increase of soil porosity and the formation of preferential flow, facilitating the vertical transport of soil nutrients.

Leaching of potentially toxic elements and safe treatment of fly ash following incineration of the cadmium and zinc hyperaccumulator Sedum plumbizincicola.

HAO Bo, ZHONG Dao-xu, ZHANG Ya-ping, WU Long-hua

2022, 41(1):  116-123.  doi:10.13292/j.1000-4890.202201.007

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We used fluidized bed incineration (800 ℃) cyclone ash to assess the feasibility of recovering metal(loid)s in the incineration ash of the hyperaccumulator Sedum plumbizincicola. We examined the factors affecting the leaching characteristics of metal(loid)s in fly ash, namely extractant type (hydrochloric acid, nitric acid or ammonium chloride) and concentration, liquid/solid ratio and leaching time. Furthermore, we evaluated the safety of the leaching residues. The type, concentration, and liquid-solid ratio of the extractant were important parameters influencing metal leaching performance, whereas leaching time had minor influence. Acids (hydrochloric acid, HCl; or nitric acid, HNO₃) showed higher leaching efficiency than ammonium chloride. The leaching characteristics of cadmium (Cd), zinc (Zn), and lead (Pb) in fly ash can bedescribedby the cationic leaching mode. The leaching efficiency of Cd, Zn, and Pb increased with increasing concentration and liquid/solid ratio of extractants, with the maximum leaching rates reaching 94.9%, 90.2%, and 92.4%, respectively. The environmental risk from leaching residues was effectively reduced by increasing the liquid/solid ratio of the extractant. An optimum leaching procedure with 1 mol·L^-1 HCl at a liquid/solid ratio of 16:1 for 30 minutes is suggested for the routine treatment of fly ash of S. plumbizincicola, which may meet the requirement for landfill. The leachates may be further used for the recovery of high-value metals.

Effects of earthworm on bioavailability of heavy metals in reclaimed soils with different thickness.

LU Fu-qing, WANG Xing-ming, CHU Zhao-xia, WANG Yun-min, FAN Ting-yu, DONG Zhong-bing, XU Xiao-ping, BAI Xin

2022, 41(1):  124-131.  doi:10.13292/j.1000-4890.202201.005

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The physicochemical properties and heavy metal level of the reclaimed soil filled with topsoil on coal gangue can significantly affect the subsequent ecological utilization. The purpose of this study was to explore the effects of earthworm on the total amount and available state of heavy metals (Cr, Cu, Pb, and Zn) in reclaimed soil with different topsoil thickness on gangue. Five thicknesses (10, 20, 30, 50, and 70 cm) were adopted for soil column experiment. Earthworms were inoculated into reclaimed soil to investigate the ecological function of earthworms on the reclaimed soil. We measured pH, organic matter (OM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), and heavy metals (Cr, Cu, Pb and Zn) contents in reclaimed soil. Within the overlying thickness of 10-70 cm, earthworm inoculation significantly reduced the pH of reclaimed soil to neutral. Compared with the control, soil OM was increased by 7.0%-13.5%, soil TN was increased by 7.5%-13.4%, TP was increased by less than 6.0%, and TK was increased by less than 2.0%. Therefore, earthworm had a good ecological improvement effect on OM and TN of the reclaimed soil. Furthermore, earthworm inoculation reduced the total amount of heavy metals and the contents of available heavy metals in reclaimed soil. The synergistic effect of earthworm and soil thickness significantly reduced the contents of total Pb and available Zn in the reclaimed soil. After inoculation of earthworms, the concentrations of total Cr, Pb and Zn, available Cr and Pb in reclaimed soil were mainly affected by TP, while the concentrations of total Cu and available Cu and Zn were mainly affected by TN. Thus, the behavior of heavy metals in reclaimed soil under earthworm inoculation was mainly influenced by TP and TN. As a result, inoculation of earthworm can improve the physical and chemical properties of reclaimed soil and reduce the concentration of heavy metals in reclaimed soil, thus producing positive ecological effects. Our results provide new ideas and methods for the reclamation of coal gangues.

Diversity of cave animal communities and the influence of environmental factors in Xianjia cave and Yiku cave in Guizhou.

ZHANG Si-qiang, DU Wei-feng, XU Cheng-xiang, HU Bi-lu, JIANG Xue-mei, ZHOU Fei, WU Yong-ying, TIAN Ya-jun

2022, 41(1):  132-141.  doi:10.13292/j.1000-4890.202201.021

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To understand the community diversity of cave animals and its influencing factors in mining area, a survey was conducted in March 2019 on the cave animals of Xianjia cave and Yiku cave in Songtao Mining Area, Guizhou Province. The effects of environmental factors on the diversity of cave animal communities were analyzed by Principal Component Analysis (PCA), and the ecological risk level of soil heavy metals in caves was evaluated by the Hakanson potential ecological hazard index. A total of 445 animal specimens were collected, belonging to 4 phyla, 8 classes, 18 orders, 32 families, with 178 specimens being collected from Xianjia cave (38 species) and 267 being collected from Yiku cave (32 species). The highest Shannon index, Margalef index, Evenness index, and Simpson index were found in light zone of Yiku cave (2.6222), light zone of Xianjia cave (6.0164), weak-light zone of Xianjia cave (0.9314), and dark zone of Xianjia cave (0.4027), respectively. Species richness, Shannon index, and Margalef index decreased in the order of light zone > weak-light zone > dark zone. The similarity index between the animal communities of Xianjia cave and Yiku cave was relatively low. PCA results showed that soil organic matter content, soil heavy metal pollution, air CO₂ concentration, cave temperature, and soil Ca content were the main environmental factors affecting the animal community diversity in both caves. The results of risk assessment of potential ecological hazards indicated that Xianjia cave and Yiku cave were at high ecological risk and extremely high ecological risk, respectively. Furthermore, Cd is the primary pollution factor in both caves.

Prediction of suitable distribution of edible tree species for Hainan gibbons based on fruit types.

DU Rui-peng, WANG Jing, ZHANG Zhi-dong, XU Yue, LONG Wen-xing, FENG Guang

2022, 41(1):  142-149.  doi:10.13292/j.1000-4890.202201.016

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Food resources are an important factor driving habitat selection for primates. Understanding the distribution of food resources is of great importance for habitat conservation and restoration for Hainan gibbon (Nomascus hainanus). A total of 180 plots were surveyed based on grids and 105 food tree species for Hainan gibbon were recorded. The MaxEnt model was used to predict the spatial distribution of six fruit edible tree species and to explore the correlation between different fruit types of tree species and environmental factors (climate and topography). The results showed that the AUC values of models for all the six fruit types were over 0.90, indicating that the modeling precision was excellent. August precipitation was the main environmental variable affecting the spatial distribution of berry, ficus fruit and nut-classified tree species, contributing to 43.8%, 27.8%, and 19.6%, respectively. Hargreaves reference evaporation was the main environmental factor affecting the spatial distribution of drupe, cone and collective fruitclassified tree species, contributing to 23.6%, 51.1%, and 58.8%, respectively. The contribution rate of mean coldest month temperature was more than 12% to six fruit types. The occurrence probability of fruit types decreased monotonously with mean temperature of the coldest month and Hargreaves reference evaporation. The concentrated distribution areas of fruit types were mainly distributed in the Futouling, Heiling and Yajiadaling, covering an area of 2392.19 hm². A total of 2346.88 hm² were located in the Bawangling Nature Reserve, accounting for 98.11%, which effectively protected the edible tree species of different fruit types. This study can provide a reference for habitat protection and vegetation restoration for Hainan gibbon.

Spatiotemporal variations of forest NPP and related driving factors based on MODIS and CASA models in Yichun.

LIU Wen-rui, LI Xiao-ting, LI Tong, JIA Bao-quan

2022, 41(1):  150-158.  doi:10.13292/j.1000-4890.202201.026

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Net primary productivity (NPP) is an important factor to judge the quality of ecosystem and carbon sink, and reflects the production capacity and ecological process of plant community, which is of great significance for regulating global carbon balance and enhancing ecological services. Based on MODIS satellite remote sensing data and improved CASA model, the dynamic changes of forest vegetation NPP in Yichun and the main affecting factors such as temperature, precipitation, and human activities were analyzed by using MOD17A3HGF NPP annual data and meteorological data from 2000 to 2019. The results showed that, from 2000 to 2019, the average NPP of forests in Yichun was 477.76 g C·m^-2·a^-1, and the NPP was mainly in the range of 400-500 g C·m^-2·a^-1, accounting for 83.30% of the total in Yichun, showing the distribution characteristics of partly high in the north and south, average in the middle, and lowest in Jiayin and Tieli Plain. The deciduous broad-leaved forest in Yichun had the highest contribution to the area with high NPP value, followed by evergreen coniferous forest. The main NPP value of coniferous and broad-leaved mixed forest was at the average level of NPP in Yichun, while the area of deciduous coniferous forest and evergreen deciduous forest was relatively small. From 2000 to 2019, the interannual NPP of forests in Yichun showed a fluctuation but overall increasing trend, among which the extremely significant increasing trend was the main one, accounting for 81.43% of the total area. On the interannual scale, there was a close correlation between annual precipitation and annual average NPP in Yichun, but a low correlation between mean annual temperature and annual average NPP. On the monthly scale, vegetation was significantly affected by temperature and less affected by precipitation, especially in the high-altitude areas such as the mountains at the junction of Yimei District, and the Korean pine concentrated area such as the southern part of Tangwang County, Fenglin Nature Reserve, Wuying National Forest Park. In the plain and low altitude areas, NPP was affected by both temperature and precipitation. Ecological projects, such as the Yichun Natural Forest Protection Project and various conservation measures, played an important role in promoting the ecological restoration of vegetation.

Stand renewal effects on the concentrations of four base cations of surface runoff in subtropical forests.

WANG Yuan, WU Fu-zhong, NI Xiang-yin, XIONG De-cheng, XU Chao, YUE Kai

2022, 41(1):  159-165.  doi:10.13292/j.1000-4890.202201.018

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Surface runoff is not only an important part of water cycling, but also a major pathway for the material fluxes in forests. Stand renewal may have significant effects on the dynamics of forest surface runoff, but this process still remains elusive. Based on a 5-year field observation in Castanopsis carlesiisecondary forest, Cunninghamia lanceolata plantation, Cunninghamia lanceolata young plantation and Castanopsis carlesii young plantation in subtropical region of Sanming, Fujian, we assessed how stand renewal affected surface runoff and the associated concentrations of four base cations (Ca²⁺, K⁺, Na⁺, and Mg²⁺). The average annual surface runoff in C. carlesii young plantation was (306.3±48.40) m³·hm^-2, which was 2.8 and 3.3 times of that in C. carlesiisecondary forest and C. lanceolata plantation, respectively. The concentrations of Ca²⁺, K⁺, Na⁺, and Mg²⁺ of surface runoff in C. lanceolata young plantation were (17.8±0.61), (16.58±1.06), (4.18±0.05), and (1.19±0.21) mg·L^-1, which were 1.6, 1.3, 1.7 and 0.9 times of those in C. carlesii secondary forest. The concentrations of all base cations varied greatly over seasons, with a general pattern of peaking in non-growing seasons. These results indicated that the total amount of surface runoff and the concentrations of base cations of runoff in the young plantations were significantly higher than that of mature forests as well as after stand renewal. These findings will help to better understand the fluxes of nutrient elements along with surface runoff as affected by stand renewal in subtropical forests, and can provide basic data for forest management and soil and water conservation.

Ecological space planning based on ecosystem services importance and ecological sensitivity: A case of Yongchun County, Fujian Province.

WANG Li-rui, DENG Xi-peng, WANG Chen, MU Zhen-bei, LI Ying, HE Dong-jin, YOU Wei-bin, WU Li-yun

2022, 41(1):  166-173.  doi:10.13292/j.1000-4890.202201.011

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 The scientific planning of ecological space is the basis for territorial space use control. Taking Yongchun County of Fujian Province as an example, we constructed the importance index of ecosystem services by selecting biodiversity protection, water conservation, and soil conservation, and by integrating forestry ecological engineering, designated prohibited development zone, and natural ecological space in cities and towns. We further synthesized the importance index with ecological sensitivity index to construct the method for the planning of county-level natural ecological space. The results showed that the territorial space of Yongchun County could be divided into three types, out of which the prohibited development zone and the restricted development zone were planned as ecological space of Yongchun County. The ecological space was 679.15 km^2 in area, accounting for 46.65% of the total area. The prohibited development zone covered an area of 258.42 km², accounting for 17.75% of the total area, while the restricted development area covered an area of 420.73 km², accounting for 28.90% of the total area. Planning can be reasonably implemented at the county level if the evaluation of forestry ecological engineering, designated prohibited development zone, and important ecological land in cities and towns were included in the importance evaluation of ecological services. More realistic references would be provided for the demarcation and supervision of ecological protection in the later stage by effectively coordinating with relevant planning and avoiding more broken patches.

A review on beetle community assembly.

JI Qiao-qiao, CHEN Ting-wen, WU Dong-hui

2022, 41(1):  174-181.  doi:10.13292/j.1000-4890.202201.035

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As a large group of arthropods, beetles have different lifestyles and play important roles in ecosystem functioning. Deciphering community assembly processes of beetles is one main research field in community ecology, which aims at elucidating the mechanisms underlying the formation and maintenance of beetle diversity in various environments. Current studies on beetle community assembly are mainly based on functional traits, or approaches integrating phylogenetic structure and functional traits of species. These methods help identify the main driving factors underlying community assembly, including biological interactions, environmental variables, and evolutionary history of beetle species. Here, we reviewed research advances on community assembly of beetles. We identified the main research fields, target taxa, and the common methods. With the existing theories and hypotheses, we summarized the factors affecting assembly processes of beetles, thereby to help improve our understanding of beetle community ecology and move forward ecological research on animal community assembly.

A review of carbon dioxide emissions from streams.

WANG Yu-chao, XU Xuan, CAO Peng-he, LIU Bo-ran, ZHOU Yan, JIN Chang-shan, WANG Wei-feng

2022, 41(1):  182-189.  doi:10.13292/j.1000-4890.202201.024

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The export of terrestrial carbon via inland aquatic ecosystems is a key process in global carbon cycle. Carbon emission from streams is greater than average carbon emission from inland water bodies, affecting the regional and global carbon budget. We summarized the temporal change of partial pressure of carbon dioxide (pCO₂) and carbon dioxide flux (FCO₂) across water bodies and atmosphere. Both pCO₂ and FCO₂ showed significant diurnal and seasonal variations, and decreased with increasing stream order. We discussed the physical, hydrochemical, and biological factors affecting stream pCO₂ and FCO₂, such as flow velocity, pH, and aquatic biomass. The contribution of autochthonous organic carbon to FCO₂ increased with stream order, which was usually lower than 50%. We outlined the challenges in future research on stream carbon cycling, such as measurement technical problems and the lack of continuous monitoring over time. We hope this review could provide new ideas and future research directions to enhance our understanding on the role of streams in the global carbon cycle.

Determination of 11 antibiotics frequently detected in municipal wastewater in China by high-performance liquid chromatography with ultraviolet and fluorescence detector.

CAO Jun, ZHANG Xue-jiao, ZHAO Qing, XING Wei-wei, ZHANG Si-yu

2022, 41(1):  190-198.  doi:10.13292/j.1000-4890.202201.002

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Municipal wastewater plant is an important source of antibiotics in the environment. Development of analytical methods for simultaneous determination of diverse antibiotics in municipal wastewater is crucial for monitoring and regulation of antibiotics. An analytic method based on highperformance liquid chromatography with ultraviolet and fluorescence detector was developed for simultaneously analyzing the presence of 11 antibiotics among four classes of antibiotics most frequently detected in wastewater treatment plants in China. Under a set of optimum analytic parameters, complete separation and detection of the 11 target antibiotics and an internal standard (R>1.5) were obtained by employing an ultraviolet detector. By employing tandem fluorescence detector, lower detection limits were obtained for fluoroquinolone antibiotics. Limits of detection for the 11 target antibiotics ranged from 4.19 to22.8 μg·L^-1, quantitative limits fell within 5.1-56.4 μg·L^-1, and recovery rates were 43.5%-102.8%. Sewage samples from inlet and outlet of a wastewater treatment plant in Shenyang were analyzed by such method. Sulfadiazine, ciprofloxacin, and norfloxacin were detected in the inlet samples, with concentrations of 440.9, 2784.8, and 515.2 ng·L^-1, respectively. In the outlet samples, only ciprofloxacin and norfloxacin were detected, with concentrations of 118.9 and 444.7 ng·L^-1, respectively. This method is convenient, time-saving, low in detection limit, and thus is suitable for regular analysis of antibiotics in wastewater treatment plants in China.

Ridge surface runoff estimation for micro-rainwater-harvestingridges on slopping land in the hilly areas of the Loess Plateau based on SCS-CN model.

2022, 41(1):  199-208.  doi:10.13292/j.1000-4890.202201.009

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To explore the mechanism underlying soil erosion control and crop yield increase in ridge-furrow rainwater harvesting production on sloping land in the hilly areas of the Loess Plateau, China, we modified Soil Conservation Service Curve Number (SCS-CN) model to estimate the runoff for different slopes (0°, 5°, and 10°) of micro-rainwater-harvesting-ridges. The curve number (CN) and the initial abstraction coefficient (λ) in the SCS-CN model were calibrated according to 19 rainfall-runoff events of micro-rainwater-harvesting-ridges on slopping land during April 1 to October 20 in 2019. The applicability of the SCS-CN model was evaluated using five rainfall-runoff events of micro-rainwater-harvesting-ridges on sloping land. The results showed that runoff increased and λ decreased with increasing slope. Effects of slope gradient on the parameters of CN were not obvious under natural rainfall conditions. The mean Nash-Sutcliffe efficiency was 0.83, 0.96, and 0.98 for the William Slope Correction Formula, Huang Slope Correction Formula, and optimized Huang Slope Correction Formula, while the mean relative error was 17.67%, 8.51%, and 5.84%, respectively. The optimized Huang approach calibrated the curve number (CN) and λ by considering slope gradient factor. Therefore, the simulation accuracy of the SCS-CN model for the optimized Huang approach was significantly higher than that for theapproaches of William and Huang. The performance of the SCS-CN model modified by the optimized Huang approach was acceptable for runoff estimation of micro-rainwater-harvesting ridges. Our results provide valuable information on soil erosion control and grain yield increase in the hilly areas of the Loess Plateau.