Table of Content

10 December 2022, Volume 41 Issue 12

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Effects of canopy and exposure duration on element concentrations of transplanted lichen Ramalina sinensis.

GAO Jing, ZHANG Liang-yu, LI Xing, MA Cui-ping, JIN Qian, LIU Lu, ZHANG Jin-ming, ZHAO Liang-cheng, MENG Jian-wei, LIU Hua-jie

2022, 41(12):  2289-2298.  doi:10.13292/j.1000-4890.202111.002

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Lichen samples are often hung under tree canopies by transplantation to monitor atmospheric element depositions. However, few studies have examined the effects of canopy (presence or absence) and exposure duration on the element composition of lichen transplants. We transplanted lichen Ramalina sinensis from a remote site to a polluted site of Hebei, China, and evaluated the bioaccumulation levels of 55 elements on the basis of the EC (exposed to control ratio). We further examined the effects of the canopy (2 levels: presence or absence) and exposure duration (3 levels: 7, 8, or 9 months exposure) on element concentrations of the transplanted samples. The results showed that background element concentrations of Ramalina sinensis were lower than the reported background/baseline values, indicating a low degree of atmospheric element deposition in the background site. Ramalina sinensis was applicable for the atmospheric deposition bio-monitoring of 53 elements except Co and Hg which had high background concentration variations. After transplantation, the concentrations of most elements were significantly higher than those in the background site. The traffic-related elements, Pb and Sb, demonstrated “extremely heavy accumulation”. The agriculture and plant physiology-related elements (As, K, P, S, and Se), as well as Ag and Ge, demonstrated “no accumulation” or “slight accumulation”. The other 44 elements (Al, B, Ba, Be, Bi, Ca, Cd, Ce, Cr, Cs, Cu, Dy, Er, Eu, Fe, Gd, Ho, La Li, Lu, Mg, Mn, Mo, Na, Nb, Nd, Ni, Pr, Rb, Tb, Sc, Si, Sm, Sn, Sr, Th, Ti, Tl, Tm, U, V, Y, Yb, and Zn) demonstrated “moderately accumulated”. These results suggest a great contribution of traffic emissions and high level of atmospheric element deposition in the exposure site. The effects of canopy and exposure duration on the element concentrations of Ramalina sinensis were element-specific. Concentrations of 26 elements under the canopy were higher than that outside the canopy, possibly due to the canopy leaching; whereas Pb showed an opposite pattern, possibly due to the canopy interception. After exposure for seven months, the concentrations of most elements (41 out of 53 elements) remained stable, while that of 11 elements increased and that of Ni decreased. Our results indicated that the presence or absence of canopy should be consistent and the length of exposure should not be too long in bio-monitoring atmospheric element deposition using transplanted lichen techniques.





Production area division of secondary forest of Juglans mandshurica in the central and eastern regions of Northeast China.

LUO Ye, YANG Yu-chun, ZHAO Shan-shan, REN Sheng, XU Chang-you, ZHU Ai-ling

2022, 41(12):  2299-2305.  doi:10.13292/j.1000-4890.202211.008

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Division of production areas of the secondary Juglans mandshurica forests is important for sustainable forest management in the central and eastern regions of Northeast China. Based on the data of annual mean temperature, extremely high temperature, extremely low temperature, mean annual precipitation, mean annual sunshine, frost-free period, and accumulated temperature, we examined the impacts of climate on the volume growth of J. mandshurica forests. The dominant factors affecting the volume of Juglans mandshurica were determined using stepwise regression analysis. Through mathematical model simulation, the optimal model was selected and its precision was tested, and the secondary forest area of J. mandshurica was divided. The results showed that: (1) Mean annual precipitation and mean annual temperature were the dominant factors affecting the volume growth of J. mandshurica, while the Delinco model was the best for describing the relationship between timber volume and the dominant factors (R²=0.89, AIC=640.07, LL=-67.16). (2) The accuracy of the mathematical model met the requirements by comparing and analyzing the relative error between the theoretical and actual volume values. (3) Based on the best-predicted model, the secondary J. mandshurica forests were divided into three production areas: the most suitable distribution area, the suitable distribution area, and the general distribution area. (4) Furthermore, a one-way analysis of variance revealed that the theoretical volume values of the three production areas were significantly different from each other (P<0.01), suggesting that the divisions of the three production areas was accurate and reliable. These results provide insights for rational management and distribution of secondary J. mandshurica forests.





Latitudinal zonality of vegetation phenophases in Greater Khingan Range.

DONG Chun-yuan, QIAO Rong-rong, WANG Ao-jie, CHANG Xue-li

2022, 41(12):  2306-2316.  doi:10.13292/j.1000-4890.202211.022

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Global climate change affects ecosystem processes by altering vegetation phenophases. However, there is few consensus on how vegetation phenophases respond to climate change at the regional scale. By using the Google Earth Engine platform and MOD09GQ, MOD13Q1 and MOD11A1 satellite data products from 2000 to 2020, we analyzed the latitudinal zonality of vegetation phenophases and the influence of temperature on forest vegetation distribution in the Greater Khingan Range. The results showed that there were significant variations in the latitudinal gradient of vegetation phenophases in the study area, and that the start of growing season (SOS) advanced on average by 0.34 d for each degree of latitude increase. Similar to the SOS, the end of  growing season (EOS) increased on average by 0.19 d for each degree of latitude increase. The length of growing season (LOS) exhibited a curvature change with an inflection point at around 50°N, and was shortened on average by 1 d for each degree of latitude increase before the point, and prolonged on averaged by 0.57 d for each degree of latitude increase after the point. SOS and LOS were more sensitive to latitude changes than EOS. Among them, the extension of LOS was mainly caused by the fact that the advance of SOS was more significantly than that of EOS. In addition, temperature directly affected vegetation phenophases in the study area, with stronger effect on SOS and LOS than on EOS. The effect of temperature in April on SOS and LOS was the most significant. The higher the temperature, the earlier SOS and the longer the LOS. The increase of LOS was mainly due to the advancement of SOS and the delay of EOS was relatively short in magnitude. The study of large-scale vegetation phenophases is principal supplementary for understanding the responses of ecological processes to climate change, with implications for forest zoning management.





Effects of slope aspect on soil rhizosphere respiration and heterotrophic respiration in Mongolian oak forest in Changbai Mountains.

SUN Zhong-lin, HUA Ming-yang, FENG Ying, JIANG Yun-tian, SONG Jin-zhi, YIN Zhi-bo

2022, 41(12):  2317-2324.  doi:10.13292/j.1000-4890.202211.024

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The division of soil respiration (R_S) components is a key step for understanding forest carbon cycle models. Uncovering the influence of slope aspect would help understand the mechanism of water and heat effects on soil respiration. The aim of this study was to quantify seasonal dynamics and flux of soil respiration components in two slope aspects, and to explore influencing factors and mechanisms. The trenching approach was used to partition R_S into heterotrophic respiration (R_H) and rhizospheric respiration (R_R) in a Mongolian oak forest. The dynamic infrared gas analyzer was used to in situ monitor soil respiration and its components in two slope aspects during the growing season. The results showed that R_S, R_H, and R_R all showed a bimodal peak curve, with significant differences between two slope aspects. The proportion of R_R was approximately the same. R_S, R_H, and R_R had a significant exponential relationship with soil temperature (T₅). The temperature sensitivity coefficient (Q₁₀) of R_H was higher than that of R_R. The Q₁₀ of R_S, R_H, and R_R of the sunny slope were all higher than that of the shady slope. Adding the variable of volume of soil water content (W₅) to the model could improve the prediction ability of soil respiration and its components. The response of different respiratory components to T₅ and W₅ was different for the same slope aspect, while the response of the same respiratory components to T₅ and W₅ for different slope aspects was different. The R_H fluxes of sunny slope and shady slope in Mongolian oak forest were 249.22 and 291.82 g C·m^-2, and R_R flux was 149.00 and 179.17 g C·m^-2, respectively. The soil respiration flux (F) showed a typical single peak curve on the monthly scale, both flux of R_H (F_RH) and flux of R_R (F_RR) showed exponential function relationship against average soil temperature (T_a) for both slope aspects, and showed a linear relationship against the precipitation. Binary linear regression was significant, but the variables and parameters were different between slope aspects and different respiratory components. The results indicated that slope variables had significant influence on R_S, R_H, R_R and their flux in same forest type. The mechanism underlying the effects of hydrothermal conditions on respiratory components was different. The parameters and variables in the model at different temporal scales reflected different ecological processes.





Effects of nitrogen addition on growth, development, and physiological characteristics of Taxus cuspidata seedlings.

MENG Qiu-shi, QIN Qian-qian, LIU Yan-hong

2022, 41(12):  2325-2334.  doi:10.13292/j.1000-4890.202211.007

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To clarify the effects of nitrogen addition on the growth-defense trade-off of seedlings of the endangered species Taxus cuspidata and provide a theoretical basis for its protection, an experiment was conducted on 4-year-old seedlings of T. cuspidata using three N types (ammonium sulfate, ammonium nitrate and potassium nitrate) and four addition levels (30, 60, 90 and 120 kg N·hm^-2·a^-1). The results showed that: (1) Height increment, basal diameter increment, and total biomass of T. cuspidata seedlings increased significantly with increasing N addition level. When the N addition level exceeded 90 kg N·hm^-2·a^-1, the basal diameter increment and total biomass began to decline. Nitrogen addition significantly reduced the root/shoot ratio of seedlings, but without significant differences among different N addition levels. (2) Net photosynthetic rate (P_n) and stomatal conductance increased significantly after N addition, peaking at 90 kg N·hm^-2·a^-1. The change of intercellular CO₂ concentration was opposite to the P_n, indicating that N addition could alleviate non-stomatal limitation of plants. (3) Flavonoid content increased firstly and then decreased after N addition, with a threshold of 30 kg N·hm^-2·a^-1. (4) After N addition, there was a positive correlation between growth and photosynthetic indices, and a negative correlation between flavanols and photosynthetic indices. The changes of net assimilation rate, relative growth rate and flavonoid indices were consistent with the predictions from the growth-differentiation balance hypothesis. (5) Compared with the single N form treatment, the addition of ammonium nitrate promoted aboveground growth, stomatal conductance and anthocyanin synthesis of seedlings. The flavonoid index increased significantly under the potassium nitrate treatment. In general, the response of T. cuspidata seedlings to N addition was related to both the amount and type of N addition. When the N addition was in the range of 30-90 kg N·hm^-2·a^-1, the growth and defense level of seedlings were better. The findings can be used as a reference measure for the ex-situ conservation and reintroduction of T. cuspidata.





Effects of planting legume green manure crops in summer fallow period of dryland winter wheat on nutrient returning, soil organic carbon and nitrogen components.

HUANG Lu, LI Ting-liang, LI Shun, LYU Zhuo-cheng, WANG Jia-hao

2022, 41(12):  2335-2343.  doi:10.13292/j.1000-4890.202211.020

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The objective of this study was to screen green manure crops suitable for planting in dryland winter wheat fallow period of southern Shanxi Province, and thus to provide theoretical basis for green production of winter wheat. An experiment was conducted to examine the effects of planting different green manure crops (sweet clover, sun hemp, soybean, black soybean, mung bean and catjang cowpea) on the amount of nutrient returning, soil microbial biomass carbon (MBC) and nitrogen (MBN), dissolved organic carbon (DOC) and nitrogen (DON), particulate organic carbon (POC) and nitrogen (PON), light fraction organic carbon (LFOC) and nitrogen (LFON), heavy fraction carbon (HFOC) and nitrogen (HFON). Results showed that total content of returning nutrient (N+P2O5+K2O) of mung bean and catjang cowpea treatments were the highest among all green manure crops, which ranged from 104.77 kg·hm-2 to 121.82 kg·hm-2. Compared with traditional farming pattern, planting green manure crops significantly increased MBC by 27%-57%, but did not affect MBN. There was no significant difference in soil DOC, POC, HFOC, LFON and HFON contents among different treatments. Compared with traditional farming pattern, black soybean and mung bean treatments significantly increased soil DON content by 27%-55%, and the soybean treatment significantly increased soil PON and LFOC content by 31% and 162%, respectively. Our results indicated that planting soybean, mung bean, and black soybean during summer fallow period had relatively high nutrient return and consequently positive effect on soil active organic carbon and nitrogen pools of winter wheat fields in the dry Loess Plateau.





Growth-promoting effect of Bacillus on maize seedlings under salt-alkali stress.

MING Li-wei, MA Ting-yu, XIAO Shan-shan, YANG Ke-jun, WANG Yu-feng

2022, 41(12):  2352-2360.  doi:10.13292/j.1000-4890.202211.014

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We explored the effects of Bacillus (Bacillus amyloliquefaciens (Bam688) and Bacillus tequila (Bte724)) on the growth of maize seedlings under saline-alkali stress. The results showed that, under saline-alkali stress, the inoculation with Bam688 and Bte724 had the strongest effect at the concentration of 1×10⁷ cfu·mL^-1. Both Bam688 and Bte724 increased the activity of antioxidant enzymes in maize seedlings, with more increase in roots than that in leaves. The content of osmoregulation substances was increased significantly after maize seedlings were inoculated with Bam688 and Bte724. Compared with the control, the content of free proline in leaves of maize seedlings inoculated with Bam688 and Bte724 increased by 254.41% and 161.84%, respectively, with more increase of free proline in leaves than that in roots. ROS accumulation and lipid peroxidation content in maize seedlings were significantly decreased after inoculation with Bacillus. Results of the analysis of NBT and DBA infection showed that the oxidation of maize seedlings was significantly alleviated. The photosynthetic pigment content of maize seedling leaves increased after inoculation with Bacillus. Compared with the control, the carotenoid content of leaves increased by 45.99% and 60.07% after inoculation with Bam688 and Bte724, respectively. Our results indicated that both Bacillus strains can promote the growth of maize seedlings and alleviate the damage caused by saline-alkali stress.





Effects of leaf litter decomposition of Pinus yunnanensis on physiological characteristics and medicinal quality in Paris polyphylla var. yunnanensis. 

XU Ling-feng, LI Zhuo-wei, GUO Dong-qin, ZHAO Jing-jing, DING Bo, ZHOU Nong

2022, 41(12):  2361-2367.  doi:10.13292/j.1000-4890.202211.012

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Understanding the effects of Pinus yunnanensis leaf litter decomposition on the physiological characteristics and medicinal quality would lay a foundation for the cultivation of high-quality Paris polyphylla var. yunnanensis. A pot experiment was conducted with five litter application levels, i.e. 0, 50, 100, 150, and 200 g·pot^-1. Samplings were taken in June (T1), July (T2), and August (T3) in 2019. The results showed that different doses of P. yunnanensis leaf litter had significant inhibitory effects on root vitality, photosynthetic pigment content and antioxidant enzyme activity in Paris polyphylla var. yunnanensis, and significant promotion effects on foliar MDA content. In each sampling period, such inhibitory and promotion effects gradually increased with increasing application levels of P. yunnanensis leaf litter. The growth and development of P. polyphylla var. yunnanensis were inhibited by the allelochemicals derived from the decomposition of P. yunnanensis leaf litter, with the total saponins content in the new and old rhizomes being inhibited. With the extension of the sampling period, the total saponin contents of new rhizomes were decreased by 3.68%-31.27% (T1), 17.23%-34.69% (T2), and 10.88%-31.03% (T3), and the total saponin contents of old rhizomes were decreased by 2.07%-25.78% (T1), 9.47%-20.90% (T2) and 5.58%-47.81% (T3), respectively. Therefore, different amounts of P. yunnanensis leaf litter reduced the medicinal value of P. polyphylla var. yunnanensis to varying degrees. Pinus yunnanensis leaf litter can affect the growth of P. polyphylla var. yunnanensis seedlings, and thus P. polyphylla var. yunnanensis is not suitable for the forest-medicine compound model under P. yunnanensis forests.





Effect of phylogenetic diversity on the stability of alpine meadows on the Tibetan Plateau.

WANG Ting, XIN Li-yu, MA Tie-shuai, ZHU Zhi-hong, DU Yan-gong

2022, 41(12):  2368-2373.  doi:10.13292/j.1000-4890.202211.019

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Grasslands with high biodiversity can make full use of resources and enhance ecosystem multifunctionality. We examined the effects of phylogenetic diversity, species diversity， and environmental factors on the stability of alpine meadow in Qinghai-Tibet Plateau by multiple linear regression and structural equation model. There were positive correlations between phylogenetic diversity, species diversity, environmental factors and the stability of alpine meadow, which was scale dependent. At the small plot scale, the stability of alpine meadow was affected by species diversity (richness) and environmental factors, with coefficients of 0.237 and 0.221, respectively. Furthermore, phylogenetic diversity was mainly affected by species diversity, with effect coefficient of 0.812 (P<0.001). At the large plot scale, ecosystem stability was mainly affected by environmental factors and species diversity, with effect coefficients of 0.364 and 0.246 respectively (P<0.05). The effects of phylogenetic diversity, species diversity and environmental factors on ecosystem stability were gradually enhanced with increasing scale, with a dominant role of environmental factors. Our results highlight the role of phylogenetic diversity and species diversity in maintaining ecosystem stability of alpine meadow.



Relationship between metazoan zooplankton community structure and environmental factors and water quality assessment in Tongzi River, Guizhou Plateau.

PAN Shao-pu, LI Qiu-hua, MA Yi-ming, WANG Xing, ZHANG Jing-ze, YANG Bo, HAN Meng-shu

2022, 41(12):  2374-2381.  doi:10.13292/j.1000-4890.202211.001

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To clarify metazoan zooplankton community structure and its relationship with environmental factors in Tongzi River, Guizhou Plateau, we investigated metazoan zooplankton and physicochemical variables in August (wet period), November (dry period) in 2020 and April (normal period) in 2021. A total of 35 species were identified, including 28 species of rotifers, 2 species of copepods and 5 species of cladophors. There were 8 dominant species, including Keratella cochlearis, Polyarthra trigla, and Phyllodiaptomus tunguidus. The abundance of metazoan zooplankton was 186.11, 55.33, 176.15 ind·L^-1, while the biomass was 0.25, 0.14, 0.17 mg·L^-1 in the wet, dry and normal periods, respectively. The diversity index showed significant spatial and temporal variations (n=75, P<0.01), with the mean values of Shannon index and Margalef index being 1.02 and 1.03, respectively, indicating that water was at α-medium pollution level. Results of redundancy analysis and principal component ana lysis showed that water temperature, chemical oxygen demand (COD_Mn), and phosphate (PO₄^3--P) were the main environmental factors affecting community structure of metazoan zooplankton. Comprehensive analysis based on dominant species composition, biodiversity index and trophic state index showed that water quality of Tongzi River was at a medium pollution state.





The effect of simulated predation stimulation on shoaling behavior of Spinibarbus sinensis with different sociability.

FU Shi-jian, LI Jia-qian

2022, 41(12):  2382-2387.  doi:10.13292/j.1000-4890.202212.011

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Using the juveniles of Spinibarbus sinensis as the experimental model, we examined the effect of simulated predation on the collective motion of fish shoals with different sociability. Twenty groups of both high and low-sociability shoals were formulated. Within each group, there were one focal fish with either high or low-sociability and nine companions with unknown sociability. The duration of stress response, number of dispersals and accelerations of fish shoals were measured before and after simulated predation stimulation. The results showed that the stress response of shoals with high-sociability was significantly shorter than that of low-sociability shoals. The proportion of high-sociability focal fish in the front of the shoals was significantly higher than that of low-sociability focal fish. However, the proportion of the position of the focal fish remained stable before and after the simulated predation stimulation. The number of dispersals decreased and the number of accelerations increased significantly after the simulated predation stimulation. However, the sociability of the focal fish did not affect both variables. Spinibarbus sinensis shoals could adaptively adjust their behavior, with a high cohesion and more confusion effect to deal with the predation risk. Fish shoals with high sociability were more sensitive to predation and had better information communication than those with low sociability.





Diversity of macroinvertebrate communities in a headwater stream in National Geopark, Dapeng New District, Shenzhen City.

HE Qian-yun, ZHANG Min, FAN Shi-bao, ZHANG Mao-lin, SUN Chen, YU Nai-qi, XIANG Hong-yong, YANG Hai-jun

2022, 41(12):  2388-2396.  doi:10.13292/j.1000-4890.202211.021

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Rapid urbanization has greatly changed hydrological processes, physical habitats and biological community structure of rivers, and thus seriously threatens the functions, services and health of river ecosystems. Headwater streams closely link surrounding terrestrial ecosystems, providing a variety of micro-habitats, and are of great significance to biodiversity conservation. To explore macroinvertebrate community structure of the headwater streams in the highly urbanized areas and its relationship with environmental factors, we investigated the macroinvertebrates and the physicochemical properties of Yangmeikeng stream, a typical headwater stream in Shenzhen in the winter of 2020 and the summer of 2021. Our results showed that a total of 2794 individuals of macroinvertebrates were collected, which could be classified into 84 taxa, belonging to two classes, 10 orders and 56 families. The macroinvertebrate communities had high biodiversity and were dominated by aquatic insects. Many rare taxa were found with a relatively small population. There were no seasonal changes in functional feeding groups. Species abundance and individual abundance of collectors-gatherers were higher than other functional feeding groups. Environmental factors, including chemical oxygen demand, dissolved oxygen, conductivity, nitrate nitrogen, pH, water temperature, wetted area width, and flow velocity, explained the variations in macroinvertebrate community diversity. Our findings provide a data basis for the research and the protection of urbanized streams in southern China.





Influence of mountain wind farm construction on soil properties and vegetation cover: A case study of Jiangjunshan wind farm in Yunnan Province.

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ZHANG Li-chen, FAN Li-zhang, MA Chang-wei, LIU Jun-hua, ZHU Yong, CHEN Zhe, WU Jian-ping

2022, 41(12):  2397-2405.  doi:10.13292/j.1000-4890.202212.010

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To explore the influence of mountain wind farm construction on ecosystem properties, we investigated soil physicochemical properties, normalized difference vegetation index (NDVI), fractional vegetation cover (FVC), and land use conversion among forest, shrubland, grassland and croplands in Jiangjunshan wind farm area in Yunnan Province. The results showed that: (1) Compared with the natural ecosystems, the construction of wind farms significantly increased soil bulk density and pH, but decreased the contents of soil water, soil organic carbon, total nitrogen and total phosphorus. Soil pH was the highest in the waste slag area in the wind farm, while the contents of soil water, soil organic carbon, total nitrogen and total phosphorus were lowest in the wind turbine area; (2) Compared with 2015, the average values of normalized difference vegetation index and fractional vegetation cover in 2020 decreased by 7.04% and 10.02%, respectively; (3) Compared to 2014, the areas of forest, shrubland and grassland in 2017 decreased by 4.65%, 3.95% and 4.17%, respectively, while the areas of cropland and construction land increased by 1.73% and 315.3%, respectively. Our findings suggest that earthwork excavation and soil compaction during construction and maintenance of mountain wind farm would decrease soil organic carbon and nutrient accumulation, and change plant community composition and vegetation cover in short term. Appropriate ecological restoration should be carried out in mountain wind farms.





Examining water conservation capacity of different vegetation types along an elevation gradient in Wuyi shan National Park based on Sentinel-2 images.

LIU Yan-qing, HUANG Shi-de, XU Dan-dan, PU Yi-han, AN De-shuai, WANG Hao-bin

2022, 41(12):  2406-2413.  doi:10.13292/j.1000-4890.202212.018

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The severe shortages of water resources have become a global issue. Water conservation as a function of forests is becoming more and more important to sustainable development. However, the difference of water conservation capacity among various vegetation types and different seasons is still unclear. In this study, we analyzed the seasonal and spatial variations of water conservation capacity of different vegetation types (i.e., evergreen broadleaved forest, meadow, coniferous forest and dwarf forest, coniferous and broadleaved mixed forest) along an elevation gradient in Wuyishan National Park. Water conservation capacity was represented by an index calculated by the ratio of normalized difference vegetation index (NDVI; i.e., calculated from Sentinel-2 images, which obtained from 2017-2020) to mountain slope (i.e., calculated from the Digital Elevation Model (DEM)). The results showed that this index was feasible to monitor water conservation capacity of different vegetation types in different seasons. The water conservation capacity of all vegetation types in different seasons was autumn > summer > spring > winter. The spatial distribution of water conservation capacity across the elevation gradient was consistent with vegetation distribution. Water conservation capacity of the four vegetation types across different seasons was in order of evergreen broadleaved forest > coniferous and broadleaved mixed forest > coniferous forest and dwarf forest > meadow.





Spatial-temporal variations in the past 30 years and prediction analysis of vegetation coverage in the northern slope of Tianshan Mountain.

LI Hong-mei, BAHEJIAYINAER Tiemuerbieke, CHANG Shun-li, ZHANG Yu-tao

2022, 41(12):  2414-2423.  doi:10.13292/j.1000-4890.202212.019

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The north slope of Tianshan Mountain is located on the Silk Road Economic Belt, with frequent human activities and many ecologically fragile areas. Exploring the temporal and spatial variations of vegetation coverage in this area is of a great significance for regional green development. Based on Google Earth Engine (GEE) cloud platform, the normalized difference vegetation index (NDVI) and vegetation coverage were calculated by using Landsat Image data from July to August of 1990, 2000, 2010 and 2020. The spatial agglomeration of vegetation coverage was analyzed by Moran’s I index, and the changes of high vegetation coverage were predicted by Grey Prediction GM (1,1) model. The results showed that: (1) Vegetation coverage on the north slope of Tianshan Mountain was generally low from 1990 to 2020, and that in 2020 showed an increasing trend compared with 1990. (2) According to the results of spatial autocorrelation analysis, the overall vegetation coverage on the north slope of Tianshan Mountain showed significant positive spatial autocorrelation (P<0.01), with an aggregation state. The results of local spatial autocorrelation analysis in different years were slightly different, which was mainly reflected in the increase of high-high aggregation in the middle part of the study area and low-low aggregation in the south edge of the study area. (3) The results of Grey Prediction GM (1,1) model showed that the average annual temperature in the study area would gradually increase from 2020 to 2040, the annual precipitation would decrease, and the area with high vegetation coverage showed an increasing trend. (4) The high efficiency of GEE cloud platform in processinglarge-scale and long-time series image data makes it an effective tool for vegetation coverage normalization monitoring.





Landscape pattern and the recreation potential of urban parks: The case of Beijing Olympic Forest Park.

HE Jia-lin, TANG Qing, LI Li, LIU Ming-yi

2022, 41(12):  2424-2431.  doi:10.13292/j.1000-4890.202211.010

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The health benefits of urban green space are based on the occurrence of recreation behaviors. Recreation potential, a product of the interaction between green space features and the observer’s psychological processes, plays an important role in the occurrence of recreation behaviors. We analyzed the landscape characteristics of 11 key park areas in Beijing Olympic Forest Park using remote sensing data. Based on the questionnaire survey of 997 visitors, we analyzed the recreation potential of the key park areas in terms of exercise suitability and scenic beauty, and ranked these areas using a combined recreation index integrating the two aspects. The relationship between landscape characteristics and recreation potential was explored. Our results showed that certain landscape indicators can potentially assist the study of recreation potential. For example, the area of deciduous forest, edge density, patch dispersion, and shape index showed different degrees of positive correlation with the recreation potential, while the area of man-made buildings and patch evenness negatively correlated with recreation potential. All the 11 key park areas showed similar graded characteristics in the ranking of exercise suitability and scenic beauty, reflecting a balanced creation of scenic-based and exercise-based recreation potentials. The study also investigated a combined recreation potential index with sub-dimensional aspects. Our study contributes to the understanding of the mechanism underlying the generation of recreation benefits in urban green space, and offers guiding implications for landscape design of urban green space.





Accumulation and ecological risk of heavy metals in soil-plant system of the contaminated area around an E-waste dismantling site.

LI Jiao-jiao, ZHAO Xue-qiang, WANG Jia-lin, LI Xiao-li, SHEN Ren-fang

2022, 41(12):  2432-2439.  doi:10.13292/j.1000-4890.202212.001

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E-waste disassembly activity is a potential threat to soil quality and safe production of crops in cropland nearby. We investigated the accumulation of Cr, Ni, Zn, Mn, and Pb in root-surrounding soils, roots, stems, and leaves of ten dominant plant species growing in cropland near an E-waste dismantling site. We used single factor pollution index, Nemerow comprehensive pollution index, and potential ecological harm index to evaluate the ecological risk of heavy metals. The absorption and transport of heavy metals in the soil-plant system were explored by bio-concentration factor, bio-transfer factor, and correlation analyses. The results showed that the pollution level of five heavy metals in soils followed the order Zn>Cr>Ni>Pb>Mn, but their ecological risk was very low. All the 10 plant species had low capacity to accumulate heavy metals. Zn was easily transported to the shoots. Root was the most sensitive organ to the content of heavy metals in soil, followed by leaf, and stem was less sensitive. The adsorption and transport of different heavy metals were synergetic in soil-plant system. These findings provide a theoretical basis for the mechanisms of adsorption and transport of different heavy metals, ecological risk evaluation, and heavy metal pollution remediation in the E-waste dismantling site.





Effects of fish invasion on aquatic ecosystem of the Yarlung Zangbo River and the prevention and control strategies.

DING Hui-ping, ZHANG Zhi-ming, XIE Cong-xin, HUO Bin

2022, 41(12):  2440-2448.  doi:10.13292/j.1000-4890.202301.012

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Alien fish invasion has become one of the important reasons for the decline of native fish resources in Tibet, but related studies remain scarce. The Yarlung Zangbo River basin is the worst-hit area invaded by alien fish species in Tibet. Alien fish species, such as Carassius auratu and Pseudorasbora parva, are widely distributed in this area, causing serious impacts on native fish resources, aquatic environment, and biodiversity. However, there are limited effective measures to control the alien fish species. We summarized the composition and distribution, transmission and dispersal routes, invasion mechanisms and ecological effects of alien fish species in the Yarlung Zangbo River. We analyzed deficiencies of current measures to control alien fish species. Countermeasures to scientifically prevent and control alien fish species were proposed, aiming to provide basis for elimination of alien fish species in Tibet and to provide reference for the protection of native fish resources and aquatic ecosystems in Tibet.





Research progress on the toxic effects of microplastics on zooplankton.

XUE Ying-hao, ZHANG Zhe, JIA Tao, LU Tian-yu, SUN Zhan-xiang

2022, 41(12):  2449-2460.  doi:10.13292/j.1000-4890.202212.020

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Microplastics are widespread in aquatic ecosystems. When the size of microplastics overlaps with the diet of zooplankton, they would be ingested by zooplankton. Zooplankton is a crucial food source for many secondary consumers. Microplastics can be transferred along the food chain, with negative impacts on the whole food web and even human beings. Based on the sources of microplastics in water environment, we described the distribution characteristics of microplastics in seawater and fresh water systems, analyzed their toxic effects on zooplankton, and pointed out the existing problems and prospects. This review enriched our understanding of the biological effects of microplastics pollution on zooplankton, and laid a foundation for the study of mechanism and biochemical reaction of microplastics in water environment.





Effects of different soil amendments on photosynthetic characteristics, dry matter accumulation and distribution of sugar beet in soda salinized cultivated land.

TIAN Lu, GUO Xiao-xia, SU Wen-bin, HUANG Chun-yan, LI Zhi, HAN Kang, JIAN Cai-yuan, XUE Chun-lei, PAN Tian-zun

2022, 41(12):  2461-2470.  doi:10.13292/j.1000-4890.202211.018

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Crop growth and yield is inhibited in soda salinized land. To select suitable soil amendments for soda salinized cultivated land in Xiliaohe Plain of Inner Mongolia, three widely used soil amendments, organic silicon fertilizer (SF), humic acid fertilizer (HF) and microbial fertilizer (MF), were deployed, with no soil amendments as the control (CK). We evaluated the effects of different soil amendments on photosynthetic characteristics, dry matter accumulation and distribution of sugar beet. The results showed that soil amendments improved the photosynthetic characteristics of sugar beet. Organic silicon fertilizer showed significant regulation effects in the whole growing period, while humic acid fertilizer and microbial fertilizer showed significant effects after the rapid growing period of leaf clumps and in the early growth stage, respectively. The regulating effect of organic silicon fertilizer was stronger than that of humic acid fertilizer and microbial fertilizer. Compared with that in CK, the P_n, C_i, T_r, G_s and SPAD value of SF increased by 10.32%-21.77%, 9.08%-19.62%, 23.14%-43.35%, 17.44%-40.93% and 23.15%-28.87%; increased by 5.63%-12.33%, 2.37%-13.60%, 4.22%-31.01%, 14.65%-32.79% and 7.93%-20.06% for HF; and increased by 3.82%-10.36%, 4.51%-10.14%, 1.46%-26.54%, 6.72%-20.45% and 5.54%-18.18% for MF, respectively. Soil amendments showed a positive regulation effect on photosynthetic characteristics and facilitated dry matter accumulation, with the best performance of organic silicon fertilizer. Compared with CK, dry matter accumulation of SF, MF, and HF was increased by 12.20%-58.06%, 3.15%-13.06%, and 5.91%-20.96%, respectively. Organic silicon fertilizer showed significant effects on regulating the distribution of dry matter in different organs compared with CK, which was conducive to transport of dry matter from leaves to petioles during the rapid growing period of leaf clusters, and promoted the transport of dry matter from leaves and petioles to roots after entering the root and sugar growth period. From the rapid growth of foliage to harvest, the proportion of dry matter in leaves decreased by 4.01%-17.43%, that in petioles decreased by 7.40%-15.87%, and that in roots increased by 3.34%-5.01%. The root shoot ratio of sweet cabbage after root tuber and sugar growth period was significantly improved by 10.88%-23.34%, compared with CK. Moreover, photosynthetic characteristics, dry matter distribution ratio of different organs were significantly correlated with sugar beet yield and sugar content. Soil amendments could improve the yield and quality of sugar beet by regulating photosynthetic characteristics and improving dry matter accumulation and distribution, with the best performance of organic silicon fertilizer.



Evaluations on topsoil water storage and water conservation capacity of the Sanjiangyuan National Park based on boosted regression trees.

ZHANG Fa-wei, LI Hong-qin, LUO Fang-lin, WANG Chun-yu, WANG Jun-bang, MA Wen-jing, YANG Yong-sheng, LI Ying-nian

2022, 41(12):  2471-2478.  doi:10.13292/j.1000-4890.202212.002

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The topsoil (0-30 cm) water properties of the Sanjiangyuan National Park are an important basis for evaluating regional water conservation and ecological carrying capacity. Results from previous studies are much uncertain due to the lack of field observation data. Based on long-term observations of topsoil water contents in the representative sites across the Qinghai Plateau, combined with the factors such as temperature, precipitation, evapotranspiration, normalized difference vegetation index, elevation, slope, and aspect, the boosted regression trees model was trained to quantify topsoil water storage and water conservation capacity of the Sanjiangyuan National Park. The results showed that the actual topsoil water storage, effective water storage, and water conservation capacity of the Sanjianyuan National Park averaged 75.20±1.98, 50.52±2.53, and 73.79±68.45 mm, respectively. The regional maximum, apparent, and minimum runoff yield averaged 47.75±65.75, -2.78±64.45, and -30.48±65.16 mm, respectively, on the premise of not considering the melting of glaciers and permafrost. The actual topsoil water storage and water conservation in the Sanjianyuan National Park increased from northwest to southeast part. The total stocks of topsoil water storage and water conservation capacity were 30.48×10⁸ and 50.80×10⁸ m³, 79% of which were concentrated in alpine meadows. These findings could provide a data basis for evaluating water resources carrying capacity and functional zoning of the Sanjiangyuan National Park.





Ecological vulnerability assessment of tropical seagrass beds and coral reefs: A case study of Sibu-Tinggi Archipelago, Malaysia.

DING Li-ke, HU Wen-jia, CHEN Bin, Kar-Hoe LOH, Jillian Lean Sim OOI, Li Keat LEE, QIU Shu-ting, GU Hai-feng, ZHENG Xin-qing, LIANG Shan-shan, DU Jian-guo

2022, 41(12):  2479-2488.  doi:10.13292/j.1000-4890.202212.014

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We developed the assessment index system for the ecological vulnerability of seagrass beds and coral reefs in Sibu-Tinggi Archipelago, Malaysia, based on the Exposure-Sensitivity-Adaptive (ESA) model. The ecolo gical vulnerability and spatial distribution of seagrass beds and coral reefs were assessed in combination with spatial analysis technology. The results showed that the spatial distribution of exposure of seagrass beds and coral reefs in Sibu-Tinggi Archipelago displayed an increasing trend from the north part to the south part. Generally, the sensitivity of seagrass beds was higher than that of coral reefs, and the ecological vulnerability of most stations were at a medium level. The vulnerability of seagrass beds was generally higher than that of coral reefs. The effects of exposure and sensitivity on the ecological vulnerability of seagrass beds and coral reefs were not relatively independent. Improving seawater quality and zoning management of marine parks have positive implications for reducing the vulnerability of marine ecosystem in Sibu-Tinggi Archipelago. Meanwhile, it is necessary to strengthen the integrated conservation of seagrass bed and coral reef ecosystems.





Construction of evaluation index for the effects of high temperature during fruit expansion period on the quality of Newhall navel orange in southern Jiangxi Province.

LI Xiang-xiang, HUANG Shu-e, XIE Yuan-yu, LI Ying-chun, YANG Jun, LI Ya-jing, DING Mei-ping

2022, 41(12):  2489-2496.  doi:10.13292/j.1000-4890.202211.015

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High temperature during fruit expansion is an important environmental factor affecting the quality of Newhall navel orange in southern Jiangxi Province. It is important to analyze the effects of high temperature on the quality of Newhall navel orange and construct a high-temperature impact evaluation index for the assessment of climatic quality of Newhall navel orange. In this study, based on multi-year quality data of Newhall navel oranges in seven main producing counties (districts) of southern Jiangxi Province and the meteorological data, we analyzed the effects of high-temperature days and accumulated heat of mean high temperature (i.e., daily mean temperature ≥30 ℃), daytime high temperature (i.e., daily maximum temperature ≥35 ℃) and nighttime high temperature (i.e., daily minimum temperature ≥24 ℃) during fruit expansion on solid-acid ratio, single fruit weight and vitamin C of Newhall navel oranges by correlation analysis. The fluctuation models of solid-acid ratio, single fruit weight and vitamin C were established by multiple stepwise regression and probability distribution fitting, and the threshold value of high temperature effect of each quality factor was determined. Finally, the high-temperature impact evaluation index (HIEI) was established by the weighted summation of the fluctuation model of each quality factor, of which the weight coefficients of each quality factor was determined by the analytic hierarchy process (AHP) method. Results showed that the effects of high temperature during fruit expansion on the quality of Newhall navel oranges were stage-dependent. High temperature in June significantly increased the solid-acid ratio and vitamin C content (P<0.05) and showed a weak positive correlation with single fruit weight (P>0.05). High temperature from July to September was negatively correlated with solid-acid ratio and single fruit weight, with a negative correlation between nighttime high temperature days and vitamin C content (P<0.01). The determination coefficient (R²) of each quality factor fluctuation model was between 0.51-0.81, and the quality fluctuation simulated by the model could well reflect the actual measured fluctuation. The thresholds of the HIEI of mild, moderate and severe levels were -7 to 0, -13 to -7, and <-13, respectively.