Table of Content

10 November 2022, Volume 41 Issue 11

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Canopy temperature and its drivers of rubber plantation in Xishuangbanna, Southwest China.

SUN Chen-na, ZHANG Jing, GNANAMOORTHY Palingamoorthy, ZHANG Yi-ping, CHEN Hui, DENG Yun, JIN Yan-qiang, SONG Qing-hai

2022, 41(11):  2081-2089.  doi:10.13292/j.1000-4890.202210.009

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Canopy temperature (T_c) is one of the key ecophysiological indices to measure plant moisture and heat. In this study, we measured T_c and other meteorological parameters (air temperature, precipitation, relative humidity, vapor pressure deficit, net radiation, and wind speed) during 2014 to 2016 in a rubber plantation, Xishuangbanna, Southwest China. We aimed to reveal the variations of T_cand its relationship with meteorological factors. The results showed that the diurnal variation of T_c exhibited a single peak in dry season and bimodal trend in rainy season. The annual variation of T_c showed a unimodal trend. The T_c was higher in rainy season than that in dry season. Furthermore, the mean T_c was always higher than air temperature throughout the year. The correlation between T_c and meteorological factors was as follows: air temperature>vapor pressure deficit>net radiation>wind speed>relative humidity>precipitation, with air temperature having the strongest effects on T_c (r=0.92, P<0.01, n=1096). Partial correlation analysis showed that air temperature, net radiation and vapor pressure deficit had significant effects on T_c in both rainy and dry seasons. The main factors influencing T_c were air temperature and net radiation in dry season, whereas air temperature and vapor pressure deficit were main factors for rainy season. This study manifested the variation characteristics of T_c and its relationship with meteorological factors in Xishuangbanna, which provided a basis for understanding the affecting factors of T_c.





Biomass allocation of three functional types of forest tree seedlings and their relationships with nutrients in fine roots and leaves.

CHANG Yun-ni, LI Bao-yin, ZHONG Quan-lin, WANG Guo-bin, SHEN Qiu-shui, XU Chao-bin, ZHANG Shi-he

2022, 41(11):  2090-2097.  doi:10.13292/j.1000-4890.202211.011

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Biomass allocation patterns reflect the strategies of plants adapting to various habitat conditions and play a vital role in global terrestrial carbon cycling. With seedlings of tree species (Machilus pauhoi, Cerasus campanulata and Fokienia hodginsii) belonged to three functional types as research objects, we used the standardized major axis estimation to test biomass allocation patterns, and used the correlation analysis to analyze its relationships with carbon (C), nitrogen (N), phosphorus (P) contents in fine roots and leaves. The results showed that allometric relationships between stem biomass and leaf biomass, root biomass and leaf biomass, as well as stem biomass and root biomass, indicating the importance of stem for biomass allocation of M. pauhoi. There were isometric relationships among leaf, root, and leaf biomass of both C. campanulata and F. hodginsii. The scaling exponents of the seedlings of the three species did not differ signifiacntly, with a common slope of 1.05 (95% CI=0.97-1.14), indicating that aboveground biomass scaled isometrically with belowground biomass. The relationships between fine root C, N and P contents and biomass allocation of the three species were as follows: Fine root C contents were positively correlated with stem mass ratio only in F. hodginsii. Fine root N contents were positively related to leaf mass ratio in M. pauhoi. Fine root N contents were negatively correlated with leaf mass ratio, and positively correlated with root mass ratio in C. campanulata. Fine root N contents were positively correlated with stem mass ratio of F. hodginsii. Fine root P contents were positively correlated with leaf mass ratio, and negatively correlated with root mass ratio and root-shoot ratio only in M. pauhoi. Fine root N∶P and stem mass ratio exhibited negative relationship in M. pauhoi. However, fine root N∶P was not correlated with biomass allocation in C. campanulata and F. hodginsii. The relationships between leaf C, N, P and biomass allocation of the three species were as follows: leaf C contents were negatively correlated with leaf mass ratio in M. pauhoi. Leaf N contents were positively correlated with stem mass ratio in C. campanulata. There was no significant relationship between leaf C contents and biomass allocation in F. hodginsii. Leaf P contents were positively correlated with stem mass ratio in only M. pauhoi. Leaf N contents and N∶P were not correlated with biomass allocation of the three tree species. Generally, the above and below ground biomass allocation patterns of the three tree species were in consistence with the isometric biomass allocation theory. However, they did not show the same allometric relationships among different organs, and the relationships between biomass allocation and leaf and fine root C, N, P contents were also different. The results indicated that different plant functional types can adapt to environment by adjusting biomass allocation patterns, which provided scientific reference for efficient cultivation of seedlings from different functional types.





Effects of organic mulching on C, N and P contents in different order fine roots of Ligustrum lucidum plantation.

WANG Gang, SUN Xiao-dan, ZHAO Jia-hao, CHEN Xia, GUAN Qing-wei

2022, 41(11):  2098-2105.  doi:10.13292/j.1000-4890.202210.008

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In this study, an experiment was conducted with four levels of organic mulching (CK, T1, T2 and T3 with the thickness of 0, 5, 10 and 20 cm, respectively, i.e. with the coverage of 0, 35, 70 and 140 kg·tree^-1, covered with a radius of 80 cm) in a 16-year-old Ligustrum lucidum plantation in Nanjing. We examined the effects of organic mulching on C, N and P contents in different order fine roots, and analyzed its affecting factors combined with soil physical and chemical properties, fine root morphology and biomass, aiming to provide scientific basis for understanding fine root nutrient utilization and near-nature management of urban soil. The C, N and P contents in different order fine roots were measured. The results showed that: (1) With increasing root orders, N and P contents in fine roots decreased, but C content showed no change. The N content in the 2nd and 3rd-order roots was significantly different from that in 4th and 5th-order root (P<0.05), while P content was significantly different among different root orders (P<0.05). (2) Compared with CK, C content under the three mulching treatments decreased in lower order (1st and 2nd-order) roots, while increased in higher order (3rd, 4th and 5th-order) roots. (3) N content of fine root in 0-20 cm soil layer under the three mulching treatments decreased compared with CK, increased in 20-40 cm soil layer, with the significant changes in low order roots (P<0.05). (4) P content of fine roots under the mulching treatments decreased in 0-20 cm soil layer. In 20-40 cm soil layer, mulching increased P content in 2nd and 3rd-order roots and decreased it in 4th and 5th-order roots. Organic mulching affects the C, N, P contents of fine roots in different root orders, accelerates soil element cycling in 20-40 cm soil layer, and improves soil environment. Organic mulching is an effective measure to promote the near-nature management of urban soils.





Leaf functional traits of greening tree species and their tolerance to atmospheric pollution in heterogeneous urban habitats.

ZHANG Yue, TIAN Qing, HUANG Rong, SONG Ling-ling, MA Yong-long

2022, 41(11):  2106-2116.  doi:10.13292/j.1000-4890.202210.010

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This study aims to examine leaf functional traits and tolerance to air pollution of greening tree species in heterogeneous urban habitats. We measured leaf morphological and physiological traits of Sophora japonica, Aesculus chinensis, Hibiscus syriacus and Buxus sinica in both road and residential habitats in Lanzhou. The scanning electron microscope was used to observe leaf epidermis structure and stomatal characteristics, and then the air pollution tolerance index, i.e. APTI, was calculated. The correlations between leaf functional traits and species’ tolerance to air pollution were explored. The results showed that: (1) In road habitat, the specific leaf area of the four tree species was lower (P<0.01), the duration of green foliage was shorter, and leaf thickness was higher than that in residential habitat. Stomatal width, stomatal opening level and opening ratio of the four tree species grown in road habitat were lower, but stomatal density was higher. All species allocated more resources to structure their leaf tissues and maintain their ability to conduct air/water exchange, in order to adapt to the road habitat. In road habitat, leaf ascorbic acid content in the tested species increased except for Aesculus chinensis. Hibiscus syriacus and Sophora japonica showed a higher value of leaf ascorbic acid content under the road habitat than that under residential habitat. The total chlorophyll content of the four tree species decreased in road habitat. Hibiscus syriacus showed a signi ficant difference of leaf pH between both habitats (P<0.01); Buxus sinica showed a significant difference of leaf relative water content (P<0.05), while other tree species showed no differences. (2) The extents of correlations differed among various leaf functional traits, with close relationships among stomatal traits, leaf morphological and physiological traits. (3) Sophora japonica showed strong tolerance to air pollution in both habitats (APTI>17), Hibiscus syriacus was intermediate (12<APTI<17), while Buxus sinica and Aesculus chinensis were sensitive (APTI<12). Sophora japonica and Hibiscus syriacus have epidermis trichomes, with coarse epidermis texture and deeper wrinkles and grains on the surface. Results of path analysis between APTI, leaf morphological and physiological traits showed that the duration of green foliage had a significant negative effect on APTI value (P<0.05), while both stomatal density and stomatal opening ratio had a significant effect on APTI (P<0.01). Our results provide a reference for selection and configuration of urban greening tree species.





Spatiotemporal variations of subtropical extreme precipitation and its influence on potential net primary productivity in China.

CHEN Qi, MAO Fang-jie, DU Hua-qiang, LI Xue-jian, YIN Shi-yan, YAN Meng-jie

2022, 41(11):  2117-2127.  doi:10.13292/j.1000-4890.202210.015

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Subtropical vegetation has strong carbon sequestration potential, and its carbon cycle is greatly affected by extreme weather caused by climate change, especially the increasing number of extreme precipitation events. In this study, we calculated six extreme precipitation indices, including continuous dry duration (CDD), continuous wet duration (CWD), maximum consecutive 1day precipitation (Rx1day), maximum consecutive 5day precipitation (Rx5day), heavy precipitation (R95p), and annual total precipitation (PRCPTOT), based on the 1 km grid meteorological data. We analyzed the spatiotemporal variations of extreme precipitation and net primary productivity (NPP) of subtropical vegetation from 1970 to 2019, and explored the effects of extreme precipitation on vegetation NPP. The results showed that all indices except CWD showed an increasing trend, with a trend of increasing extreme rainfall abnormal events and insignificant aridification. There were significant spatial variations of rainfall. The closer to the northwest, the drier it was, and the wetter it was to the southeast. NPP of subtropical vegetation in China increased at a rate of 5.8 g C·m^-2·10 a^-1. The spatial distribution of mean annual NPP decreased from southeast to northwest, and the overall spatial variation was small. NPP was mainly positively correlated with extreme precipitation index and CWD, and negatively correlated with CDD. NPP was most sensitive to the change of CWD. The spatial variation of sensitivity to CDD was the largest. The longer the dry period and the more extreme precipitation, the higher sensitivity of NPP to extreme precipitation, while the longer the wet period, the lower the sensitivity of NPP to it. The results will provide theoretical support for the evaluation of extreme weather and its impacts on NPP in subtropical regions, and important data support for understanding response of subtropical vegetation to climate change.





Soil phosphorus characteristics of different land use types and ecological restoration modes in karst region.

QIAN Qian, ZHANG Run-yang, LIU Kun-ping, LIANG Yue-ming, ZHANG Wei, PAN Fu-jing

2022, 41(11):  2128-2136.  doi:10.13292/j.1000-4890.202208.003

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We explored the effects of land use types and ecological restoration modes on soil phosphorus (P) characteristics in karst ecosystems, with three land-use types (orchard (loquat), pastureland, and disturbed land) and four restoration modes (evergreen forest, deciduous forest, evergreen-deciduous mixed forest, and naturally restored forest) being selected. We measured soil phosphorus \[(total phosphorus (TP), available phosphorus (AP) content, microbial biomass phosphorus (MBP)\] and analyzed the relationships between the three P variables and soil pH, organic carbon (SOC), total nitrogen (TN), ammonium nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃^--N), exchangeable calcium (Ca), magnesium (Mg), microbial biomass carbon (MBC), and nitrogen (MBN). Results showed that soil TP across different land-use types was higher than that across different restoration modes, while MBP showed an opposite pattern. Among the land-use types, pasture had the highest TP and AP and lowest MBP, orchard had the highest MBP, and disturbed land had the lowest TP and AP. Across the restoration modes, soil AP and MBP in the naturally restored forest and deciduous forest were significantly higher than those in evergreen-deciduous mixed forest and evergreen forest. Soil TP was not different among the four restoration modes and was positively correlated with SOC, TN, and exchangeable Ca. Soil AP was positively correlated with pH, MBC, MBN, MBP, and exchangeable Mg, while soil MBP was positively correlated with exchangeable Ca and Mg, MBC, and AP. Results of redundancy analysis showed that soil MBC and MBN significantly influenced the variations in soil P content across different land-use types and restoration modes, indicating that soil P availability in these karst ecosystems was extremely affected by soil microbial activities. The orchard had higher soil TP, AP, and MBP across three land-use types, with values approximating that in the naturally restored forest, suggesting that it would be an appropriate land-use type. The deciduous forest had higher soil TP, AP, and MBP than those in evergreen-deciduous mixed forest and evergreen forest, similarly to the naturally restored forest, which suggested that deciduous tree species can be planted in the recovered areas to enhance vegetation restoration in karst ecosystems.





The characteristics of soil salt ions under different diffusion stages of Sophora alopecuroides in the Yili River valley.

LIU Shu-qi, CUI Dong, GU Jie, LIU Wen-xin, ZHAO Yang

2022, 41(11):  2137-2144.  doi:DOI:10.13292/j.1000-4890.202211.009

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To explore the relationship between the distribution of Sophora alopecuroides and soil salt ions, we analyzed the vertical distributions of ions (cations: Na⁺, Ca²⁺, Mg²⁺, and K⁺; anions: HCO₃^-, CO₃^2-, Cl^- and SO₄^2-), ion ratios in different soil layers, and the correlations between the ion concentrations of soils beneath S. alopecuroides with different coverage, Cynodon dactylon, Bothriochloa ischaemum, and Bothriochloa ischaemum in Yili River valley. The results showed that total salt content of soil beneath S. alopecuroides decreased with increasing S. alopecuroides coverage. Total salt content of topsoil (0-30 cm) was higher than that of subsoil (30-60 cm), suggesting that salt had the characteristics of surface accumulation in soils beneath S. alopecuroides. The distribution of salt ions across the soil profile was uneven, which was overall as follows: Na⁺>K⁺>Cl^->SO₄^2->Ca²⁺>Mg²⁺>HCO₃^-, with CO₃^2- being not detected. The Na⁺/Ca²⁺, Na⁺/Mg²⁺, and Na⁺/K⁺ ratios indicated highest enrichment degree of Na⁺ in rhizosphere soil of S. alopecuroides. The uptake rate of Na⁺ by S. alopecuroides was lower than that of Ca²⁺, Mg²⁺, and K⁺. There were significant correlations between total salt and other ions (P<0.05). Our results indicated that the higher the salt concentration, the lower the S. alopecuroides coverage, providing a theoretical basis for the management and control of S. alopecuroides in Yili River valley grassland.








Simulation analysis of the spatial and temporal distribution of soil organic carbon storage in Gannan alpine meadow.

CAO Rui-hong, ZHANG Mei-ling, LI Xiao-juan, LUO Shang-xue, JIA Xiao-nan, ZHU Mei-ting, NIE Ya-mei

2022, 41(11):  2145-2153.  doi:10.13292/j.1000-4890.202210.022

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We examined the spatiotemporal distribution of soil organic carbon storage in Gannan alpine meadow. According to the monthly meteorological data and soil type data from 1971 to 2020 in Gannan and its surrounding meteorological stations, we parameterized the CENTURY model to simulate soil organic carbon storage and its dynamics. The simulation results were used to model the spatial and temporal variations of soil organic carbon (0-20 cm). The results showed that soil organic carbon storage decreased from southwest to northeast in the past 50 years. A similar trend was observed from west to east. The variation of total soil organic carbon storage and was in quite consistent with that of slow fraction. In 1971-2020, the average soil organic carbon storage in Gannan was 8444.40 g·m^-2. The soil organic carbon storage was 270.12, 4516.70, and 3478.77 g·m^-2 in the active, slow, passive fractions, respectively. Luqu and Maqu counties were the main areas with high soil organic carbon storage, while Hezuo City had low soil organic carbon storage. Altitude, temperature, and precipitation were the main factors affecting soil organic carbon storage. Spatially, soil organic carbon storage was positively correlated with altitude and precipitation, but negatively correlated with temperature.





Population dynamics of Frankliniella occidentalis on chrysanthemum seedlings under different planting environments in Kunming.

PENG Xiao-qin, LEI Zhi-yuan, LI Yi-ru, WANG Yue, TU Yan-fang, CHEN Zhi-xing, PU Xiao-mei

2022, 41(11):  2154-2162.  doi:10.13292/j.1000-4890.202210.018

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We used five-point sampling and sticky board method to investigate population dynamics of F. occidentalis on chrysanthemum seedlings under different planting environments. The effects of F. occidentalis size of fore-rotating seedlings on F. occidentalis size of current-rotating seedlings were analyzed from 2018 to 2020. The results showed that population size of F. occidentalis increased first and then decreased in both the fore-rotating and current-rotating seedlings. The duration of the main activity period of F. occidentalis was related to the planting time of chrysanthemum seedlings. The main activity period of F. occidentalis on fore-rotating seedlings were from late March to late June under different planting environments, with peak population size of 654.6 ind·board^-1 in open field, 373.8 ind·board^-1 in single greenhouse and 146.4 ind·board^-1 in conjoined greenhouse. The main activity period of F. occidentalis on current-rotating seedlings was from mid-July to mid-October, while population peaked to 551.2 ind·board^-1 in single greenhouse, 134.3 ind·board^-1 in open field and 57.7 ind·board^-1 in conjoined greenhouse. F. occidentalis population size on fore-rotating seedlings during the main activity period was in an order of open field > single greenhouse > conjoined greenhouse, while that on current-rotating seedlings was in an order of single greenhouse > open field > conjoined greenhouse. The effect of F. occidentalis population size of fore-rotating seedlings on F. occidentalis population size of current-rotating seedlings was increased in an order of open field > single greenhouse > conjoined greenhouse. The population size of F. occidentalis of fore-rotating seedlings in conjoined greenhouse had the lowest influence on that of current-rotating seedlings, which could effectively control the population size of F. occidentalis on the chrysanthemum seedlings.





Estimation models of green and dead standing aboveground biomass of Cyperus malaccensis.

LIU Bai-gui, TONG Chuan, HUANG Jia-fang, TAN Ji, LI Hui

2022, 41(11):  2163-2170.  doi:10.13292/j.1000-4890.202210.001

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Constructing allometric equation is a common method for non-destructive estimation of plant above-ground biomass (AGB). Cyperus malaccensis is a common emergent macrophyte in the estuarine tidal wetlands of Fujian and Guangdong, the allometric equation of which has not been reported. In this study, we monthly measured plant height, base diameter, fresh and dry mass of C. malaccensis shoots in the Minjiang River estuary. Based on these indicators, the allometric equations of dry and fresh mass of both the green and dead standing AGBs of C. malaccensis individuals were established with different accuracy and practicability. The dry and fresh mass (g) models are y=exp(0.14x²+0.32x-4.28) and y=exp(0.08x²+0.58x-2.56), respectively, while the dry mass (g) model of dead standing plant is y=exp(1.48x-6.76) (x is the natural logarithm of plant height (cm)). Based on the AGB models of individual plant, we established the rapid green plant AGB estimation models per unit area. The modeling method proposed here is valuable for the AGB modeling of other salt marsh plants in estuaries and coastal areas. The models built in our study can provide technical support for the estimation of AGB and blue carbon sink of the coastal C. malaccensis marshes.





Ecosystem service value of mine park under ecological restoration background: A case study of Zijin Mountain in Fujian Province.

LUO Lin, YANG Lu, XIE Hong-bin, GUAN Zhao, WEI Ping

2022, 41(11):  2171-2179.  doi:10.13292/j.1000-4890.202210.023

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To explore the ecosystem service value of mine parks is of great significance to reasonably formulating mining ecological restoration policies, efficiently allocating environmental resources, and precisely planning future development paths. In this study, based on land use data and questionnaire data, we evaluated the ecosystem service value of Zijinshan Mine Park in Shanghang, Fujian Province, using unit area value equivalent factor method and conditional value method. The land use structure of the park varied significantly from 2005 to 2018. The net change of forest land was the largest, and the area of grassland and bare land increased gradually. The total ecosystem service value of the park increased from RMB 457.95 million in 2005 to RMB 478.04 million in 2012, and then decreased to RMB 417.65 million in 2018. Under the dual effects of “repairing while mining”, the ecosystem service value showed a trend of “overall decline and partial improvement”. Based on community residents’ positive attitude and their willingness to pay for the potential cultural service of the park, the total cultural service value of the park was estimated as RMB 140 million per year. Great value potential and residents’ recognition of environmental education and leisure and recreation play a basic role in driving the favorable development of the park.





Ecohydrological restoration effect of ecological water conveyance in Ejina oasis, lower reaches of the Heihe River in recent 20 years.

WANG Chuan, ZHANG Yong-yong, ZHAO Wen-zhi

2022, 41(11):  2180-2187.  doi:10.13292/j.1000-4890.202210.017

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To understand the eco-hydrological responses of the ecological water conveyance project (EWCP) in the Heihe River, we used long-term monitoring data and remote sensing data, and employed spatial analysis, trend analysis, regression analysis and structural equation modeling to identify the spatial and temporal variations in groundwater depth, surface water bodies and NDVI in Ejina oasis in the lower reaches of the Heihe River since the implementation of the EWCP (2000-2020). The responses of oasis hydro-ecological indicators to the EWCP were analyzed, and the structure and strength of the drivers of vegetation restoration were clarified. The results showed that during the last two decades, the average annual runoff at Langxinshan hydrological station (LXS) showed a significant increase trend with 2.7×10⁷ m³. The groundwater level raised by 0.41 m on average. The area of the surface waterbody increased by 130.62 km². The NDVI showed a significant increasing trend, with the increased region occupying 42.34% of the total area. The middle reaches of the West River and the lower reaches of the East River dominated the rise of the NDVI. The response of NDVI to runoff was more sensitive in the West River area than that in the East River area. The vegetation area and NDVI remained relatively high level when the runoff in LXS was over 6×10⁸ m³ and the mean groundwater depth was lower than 2.8 m. Runoff, groundwater depth, and farmland area had different degrees of direct and indirect effects on oasis vegetation. The guarantee of runoff and the stability of groundwater in the lower reaches of Heihe River are the key drivers for the restoration and sustainable development of Ejina oasis.





Effects of different agroecosystems on population dynamics of Bemisia tabaci and its natural enemies in summer tomato fields.

LI Ming-jiang, ZHANG Ze, LIU Yu-han, YANG Shao-wu, SHANG Hao-pei, JIANG Zheng-xiong, LI Xing-xing, CHEN Guo-hua, ZHANG Xiao-ming

2022, 41(11):  2188-2198.  doi:10.13292/j.1000-4890.202210.020

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We examined the dynamics of Bemisia tabaci and its dominant natural enemies in tomato fields from three major types of agroecosystems in Kunming, Yunnan Province, including flower, river, and mountain. Five-point sampling method was used to systematically quantify the numbers of B. tabaci and its natural enemies. The population dynamics of B. tabaci were analyzed by quartile method. The niche correlation index was used to analyze the relationship between B. tabaci and its dominant natural enemies in temporal niche. The results showed that tomato field in flower agroecosystem held the lowest densities of nymphs and adults B. tabaci during main activity period, which were 44.66 and 36.25 individuals per plant, respectively. The nymphs and adults B. tabaci in tomato field of river agroecosystem had the highest densities, which were 645.79 and 449.04 individuals per plant, respectively. Tomato field in flower agroecosystem had the maximum natural enemy species, including Nesidiocoris tenuis, Menochilus sexmaculatus, Harmonia axyridis, Encarsia formosa and Eretmocerus hayati. The population densities of N. tenuis, M. sexmaculatus, H. axyridis and E. formosa in tomato field of flower agroecosystem were 1.90, 1.66, 1.79, 2.19 fold to river agroecosystem, and 1.61, 1.16, 1.24, 1.43 fold to mountain agroecosystem during in main activity period, respectively. M. sexmaculatus had the largest temporal niche overlap with B. tabaci in tomato field of the three agroecosystems. Moreover, M. sexmaculatus had the closest spatial-following relationship with B. tabaci, with the gray correlation degrees with B. tabaci in flower, river and mountain agroecosystems being 0.32, 0.38 and 0.35, respectively. The largest temporal niche overlap index of dominant natural enemies and B tabaci presented in flower fields of agroecosystem tomato, indicating that increasing the proportion of flowering plants around cropland can increase the diversity of natural enemies and thus inhibit the outbreak of B. tabaci population.





Community characteristics of zooplankton and its relationship with environmental factors in Shibalianwei wetland of Hefei City in summer.

SUN Shang-sheng, DU Cai-li, LU Di, LI Jia-zheng, XIE San-tao, ZHANG Wei, WANG Li-qing

2022, 41(11):  2199-2207.  doi:10.13292/j.1000-4890.202208.005

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Shibalianwei is a super large constructed wetland located in the estuary of River Nanfei and Lake Chaohu. To clarify the characteristics of zooplankton communities and the relationship between zooplankton and water environmental factors, water samples were collected from 72 sites of Shibalianwei wetland from June to July 2018. A total of 114 zooplankton species were identified, including 36 species of Protozoa (32%), 46 species of Rotifera (40%), 19 species of Cladocera (17%), and 13 species of Copepoda (11%). The abundance of zooplankton in Shibalianwei wetland was mainly contributed by Protozoa and Rotifer, with the highest contribution of Protozoa. The results of Shannon diversity index showed that the Shibalianwei presented an overall trend of α-medium pollution type and a few river sites reached β-medium pollution. Results of canonical correspondence analysis showed that  total nitrogen, dissolved oxygen, and soluble reactive phosphorus were the primary environmental factors affecting zooplanktoncommunity structure. Our results provide a reference for the construction and ecological protection of the Shibalianwei wetland as well as essential data for its function of reducing pollution load of Lake Chaohu.





The population status and habitat suitability of wild boar in southern Laoyeling, Heilongjiang Province.

LIU Yan-hua, LI Wei-dong, ZHANG Zi-dong, LIANG Zhuo, YANG Jiao, NIU Ying-ying, ZHOU Shao-chun

2022, 41(11):  2208-2215.  doi:10.13292/j.1000-4890.202211.013

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Wild boar (Sus scrofa) is a major prey species of Amur tiger (Panthera tigris altaica). In order to understand the status of prey resources, we conducted large-plot surveys in the southern part of Laoyeling, Heilongjiang, China, which is one of the main strongholds of wild Amur tiger population, during the snow cover periods in winter of 2016, 2018 and 2019. We collected information on the footprints of wild boar and analyzed population density, population number, and distribution of wild boar. Based on the presence data, the habitat suitability of wild boar was evaluated using MaxEnt model. The results showed that population density of wild boar was 1.07±0.01 individuals·km^-2, and the population size was 3436-3518 individuals. Population density was the highest in the Laoyeling Amur Tiger National Nature Reserve and Muling Japanese Yew National Nature Reserve. The results of habitat analysis showed that environmental variables—cropland (36.0%), evergreen coniferous forest (23.2%), road (7.5%), grassland (7.1%), mixed broadleaf-conifer forest (5.2%), and altitude (2.2%)—had significant effects on the habitat suitability of wild boar. There were 499.28 km² of suitable habitat, accounting for 15.36% of the total area. Combining the long-term monitoring data of the Amur tiger and the results from this study, we conclude that the protection and restoration of wild boar population outside the reserve is important for realizing the migration of the Amur tiger from the south to the north of the Laoyeling Mountains, meeting the needs of the Amur tiger for prey resources, and realizing the gradual reproduction of wild Amur tiger population in China.





Effects of stand age and tidal zone on the distribution of microplastics in mangroves near lagoon.

SHI Yun-feng, WANG Shuai, WANG Hui, WANG Sheng-yuan, HAN Qiu-ying, ZHAO Mu-qiu

2022, 41(11):  2216-2225.  doi:10.13292/j.1000-4890.202208.004

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Due to the unique geographical location and environmental characteristics, mangrove wetlands have become sinks of various pollutants. In this study, we investigated the distribution characteristics of microplastics in water and sediments of adult (>20 year-old) and juvenile (4 year-old) mangroves at different tidal zones in the west of Xincun lagoon in Lingshui County, Hainan Province. The results showed that the abundance of microplastics in surface seawater and sediments in adult mangrove (91.2±15.0 n·L^-1, 1972.9±805.2 n·kg^-1) was significantly higher than that of juvenile mangrove (49.1±7.3 n·L^-1, 686.2±64.3 n·kg^-1). The abundance of microplastics in different zones of adult mangrove was the highest on the landward (2822.7±309.6 n·kg^-1) and the lowest on the seaward (1221.3±292.9 n·kg^-1). The proportion of film microplastics in seawater was lower than that in sediments (6.5% vs 14.0%), while that of foam was higher in seawater than in sediments (23.8% vs 15.9%). There were no obvious patterns for the morphological distribution of microplastics in sediments in terms of stand age and tidal zone. The particle sizes of most microplastics (93.3%) ranged from 50 to 2500 μm, in which the proportion of 100-250 μm microplastics was higher on the seaward than that on the landward, both in adult and juvenile mangroves. The microplastics with white color had the highest proportion (39.2%), followed by blue (21.6%). The proportion of white microplastics in the sediments of juvenile mangrove was higher than that of adult mangroves, with the highest proportion on the landward, the lowest on the seaward, while higher proportion was found on the seaward than that on the landward in adult mangroves. The main materials of microplastics in mangroves were polyethylene (39.6%), polystyrene (28.3%), and polypropylene (20.8%), and were seriously eroded and weathered. Overall, mangrove ecosystems have the function of accumulating microplastic pollutants, and such ability is the strongest in adult mangroves on the landward.





Spatiotemporal evolution and coupling coordination of land use benefits in Lanzhou-Xining urban agglomeration.

ZHANG Wei-ping, SHI Pei-ji, YIN Jun-feng

2022, 41(11):  2226-2235.  doi:10.13292/j.1000-4890.202210.021

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By clarifying the connotation of social, economic, and eco-environmental benefits system of land use, we constructed the comprehensive evaluation index system of land use benefits in Lanzhou-Xining urban agglomeration. Based on entropy weight method and comprehensive index model, we analyzed the spatial variations of land use comprehensive benefits and social, economic, and eco-environmental benefits of Lanzhou-Xining urban agglomeration in 2005 and 2018, and evaluated the coupling coordination among principal components using coupling coordination degree model. The results showed that the social, economic, and eco-environmental benefits of land use in Lanzhou-Xining urban agglomeration displayed an upward trend. The spatial clustering characteristics of social and economic benefits were obvious, showing a distribution characteristic of “high in the east and low in the west”. The regional variations of eco-environmental benefits were relatively small, showing scattered distribution. The comprehensive benefits of land use showed an upward trend, with significant differences among counties. There was a spatial pattern of “high in the east and low in the west; high in the middle and low in the periphery”, while the central cities and prefecture-level cities were at a high level for a long time. The coupling and coordination among social, economic and ecological environmental benefits of land use tended to be improved as a whole, but only in the primary coordination stage at present. The coordination of Lanzhou and Xining provincial capital cities was better than other county towns. The coupling and coordination of land use benefits was mainly affected by the combination of three kinds of land use benefits. The lag of social benefit was the main reason restricting the promotion of coupling and coordination relationship of land use benefits, while the lag of eco-environmental benefit affected coupling and coordination of land use benefits.





Impacts of road network on landscape pattern and landscape ecological risk: A case study of Ruijin-Xingguo-Yudu region.

LU Qing, LIU Gen-lin, YAN Bing, ZHAO Dong-sheng

2022, 41(11):  2236-2244.  doi:10.13292/j.1000-4890.202210.019

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Based on land use data and road data of 2013 and 2018, we explored the impacts of road network on landscape pattern and ecological risk in Ruijin-Xingguo-Yudu region. Using kernel density estimation, buffer analysis, road contribution rate and geographically weighted regression model, we analyzed the responses of landscape pattern and ecological risk to road network construction. The results showed that road density grade of Ruijin-Xingguo-Yudu region generally increased, being more obvious in the central area. The PD index decreased with increasing buffer distance, the LPI index and the CONATG index increased, and the SHDI index increased first and then decreased. The road network had a great impact on the landscape index of construction land, but little impact on the landscape pattern index of forest land, grassland, and water bodies. The overall landscape ecological risk of the study area evolved to a higher level, with the proportion of medium-level, high-level and extremely high-level areas increasing from 24.76%, 19.49%, and 14.96% in 2013 to 26.61%, 22.80%, and 15.64% in 2018. Landscape ecological risk had strong spatial heterogeneity, with high-level risk areas being mainly located in the basin areas of Xingguo and Yudu, and low-level risk areas generally located in high altitude areas, mostly in the mountainous landforms. The results of geographical weighted regression showed that the ecological risk of landscape was negatively correlated with the shortest distance from the sampling center to the road and positively correlated with road density. Our results have implications for regional planning and construction and ecological environment protection of Ruijin-Xingguo-Yudu region.





Effects of nitrogen deposition on soil N₂O emission during freezing-thawing period: A review.

LIU Yan-qi, PENG Qin, QI Yu-chun, LI Zhao-lin, HU Bei-bei, DONG Yun-she

2022, 41(11):  2245-2253.  doi:10.13292/j.1000-4890.202210.003

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N₂O is one of the three most important greenhouse gases, which could destroy the ozone layer. The N₂O loss from soil determines the status of soil nitrogen stock. In recent years, the response of soil N₂O emission to glo-bal change factors such as nitrogen deposition has attracted extensive attention. However, most studies are concentrated in the growing season, and less focuses on the non-growing season, especially in the freezing-thawing period. By reviewing the existing literature, we summarized the impacts of nitrogen deposition on soil N₂O emission in non-growing season, and discussed the possible mechanisms underlying the impacts of nitrogen deposition on soil N₂O emission in freezing-thawing period from the aspects of soil physical and chemical properties and soil microbiological characteristics. We pointed out the shortcomings of previous researches, and put forward to research direction, aiming at providing a reference for in-depth understanding of emission characteristics of soil N₂O and its driving mechanism under the background of global change, and for further taking effective measures to control soil N₂O emission.





Riceduck farming: A review.

LIANG Yu-gang, ZHAO Yang, DAI Li, KUANG Wei, FANG Bao-hua, ZHAO Zheng-hong, HUANG Huang

2022, 41(11):  2254-2262.  doi:10.13292/j.1000-4890.202208.006

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The rice-duck farming system is one of the most important components of Chinese agriculture culture, with a long history and obvious advantages in rice production. After more than one thousand of years of development, the rice-duck farming has been transformed from scatter-feeding, mobile-grazing and camp-feeding to the modern technology system, with good social, ecological and economic benefits. Here, we introduced the concept, developing history, and the major patterns of rice-duck farming system. We summarized the research advances on rice-duck farming regarding economic benefits, rice yield, growth characteristics, farmland ecological environment, water ecological environment, biodiversity, and greenhouse gas emissions. In addition, we discussed the prospects of rice-duck system in terms of regionality, practicability, systematicness, long-term effects, and brand building. This review might provide support for enhancing yield potential, quality, and sustainability of rice-duck system.





Predicting the potential distribution of Crossoptilon auritum based on MaxEnt model.

YOU Zhi-yuan, WANG Ming, LU Bi-geng, LIU Wei, YANG Nan

2022, 41(11):  2271-2277.  doi:10.13292/j.1000-4890.202211.016

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Crossoptilon auritum is a bird distributed in high-altitude forests and shrublands of the central and western China. In this study, we used MaxEnt model to predict the geographical distribution of C. auritum in China and examined environmental factors driving its distribution, based on 158 presence points and 12 environmental factors. The results showed that the suitable habitat area of C. auritum was 2.23×10⁵ km² in China, which was mainly distributed at the junction of Sichuan, Qinghai and Gansu provinces and spread out in all directions. The sub-suitable habitat area was 3.13×10⁵ km², concentrated in the periphery of suitable habitats. The main environmental factors and optimum ranges of habitat suitability for C. auritum were altitude (2000-3800 m), mean temperature of the warmest quarter (9-18 ℃), isothermality (30%-38%) and vegetation types (coniferous-broadleaf mixed forests, coniferous forests, and shrublands). Results of the Jackknife test showed that the AUC (area under curve) value of altitude and its gain was the highest, which was one of the most important environmental factors affecting the habitat suitability of C. auritum. Our findings provide scientific basis for further clarifying the geographical distribution of C. auritum in China and formulating effective conservation strategies.





Analysis of influencing factors on forest soil organic matter in Guangdong Province based on GAM model.

LIU Xiao-tong, HUANG Jin-jin, ZHANG Yi-ru, LI Hai-kui

2022, 41(11):  2278-2288.  doi:10.13292/j.1000-4890.202210.007

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Understanding the influencing factors of forest soil organic matter can provide reference for forest management and quality improvement. In this study, we used Kriging interpolation method to analyze the spatial distribution of soil organic matter in forests of Guangdong Province based on 1182 sampling plots. With 52 factors of geography, topography, stand, climate, soil physics, and forest management as explanatory variables, and soil organic matter as the response variable, the factors that significantly influenced soil organic matter were selected by using the generalized additive model (GAM). The qualitative and quantitative factors with significant effects were interacted respectively to obtain the interaction terms. The results showed that: (1) The distribution of forest soil organic matter showed spatial heterogeneity, characterized by high content in the northwest areas, moderate in the west-central areas, and low in the southern coastal areas. (2) GAM could better fit the nonlinear relationship between the response variable and explanatory variables. The factors with extremely significant effects on soil organic matter included slope level, dominant tree species, soil water content, non-capillary water storage capacity, and non-capillary porosity capacity, while the factors with significant effects were longitude, slope direction, altitude, number of species, humus layer thickness, isothermality, annual minimum temperature and soil thickness. The modified determination coefficient and the explanation rate of variance of the single-factor GAM were 0.502 and 59.7%, respectively. The interactions between three qualitative factors (dominant tree species, slope level, and slope direction) and eight quantitative factors (longitude, humus layer thickness, isothermality, annual minimum temperature, soil water content, non-capillary water storage capacity, non-capillary porosity capacity, and soil thickness) had significant effects on soil organic matter. The modified determination coefficient and the explanation rate of variance were improved to 0.515 and 59.8% by adding the interactive items. Our results indicated that forest soil organic matter in Guangdong Province was mainly affected by geography, topography, stand, climate and soil physical factors, among which topography and soil physical factors had great effects. Our results can provide reference for forest quality improvement and rational forest management in Guangdong Province.