Table of Content

15 July 2019, Volume 30 Issue 7

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Special Features of Terrestrial Ecosystem and Agroforestry Meteorology

GIS-based ecological climate suitability regionalization for Cordyceps sinensis in Shiqu County, Sichuan Province, China.

WANG Qing-li, HAN Yu-jiang, ZHANG Li-ping, FENG Chao, WANG Ming-tian

2019, 30(7):  2137-2144.  doi:10.13287/j.1001-9332.201907.022

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Based on the biological characteristics of Cordyceps sinensis, combined with the spatial and temporal distribution characteristics of local agro-climatic resources and the investigation data of C. sinensis resources, we investigated the ecological climate suitability regionalization and the spatial distribution of C. sinensis in Shiqu County using mathematical statistics analysis, optimization method and GIS spatial analysis. We used altitude, mean annual temperature, mean annual precipitation, vegetation, and soil as the leading indicators and topographic gradient as the auxiliary indicators, as the main basis for the suitability zoning of C. sinensis resources. The results showed that C. sinensis grew in most of the townships in Shiqu County, with their distribution areas being fragmented and scattered, showing sporadic patches and blocks. They were mainly distributed in east and west parts of the county and in the Zhaqu River basin in the central part. The suitable distribution area for C. sinensis in Shiqu was 4000-4700 m above sea level, with mean annual temperature of -2.5-3 ℃ and mean annual precipitation of 550-850 mm. The growth environment was generally alpine mea-dow and subalpine meadow with good hydrophobicity and slope of 15°-50°. The suitable growth environment and meteorological conditions were beneficial to the growth and development of feeding plants and bat moths. The unsuitable area was in the high mountain area above the river wide valley area, pastoral area, wetland, or snowline.

Estimating evapotranspiration of plantation with non-uniform terrain based on two-wavelength method.

ZHANG Gong, ZHANG Jin-song, MENG Ping, YIN Chang-jun

2019, 30(7):  2145-2155.  doi:10.13287/j.1001-9332.201907.018

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Kilometer-scale evapotranspiration is usually estimated by remote sensing images, combined with empirical or semi-empirical models, with results being verified with empirical data. However, it is usually difficult to obtain real-time measurements which can match the pixel scale of remote sensing. We analyzed kilometer-scale evapotranspiration by the combination of near-infrared and microwave technique in the Ecosystem Research Station of the Yellow River in Xiaolangdi, during period of plantation growth (1st July to 19th October 2016). Results showed that the combination of near-infrared and microwave technique could obtain well diurnal cycles in different weather conditions, with the overall energy balance reaching 0.87. The technique was sensitive to the variation of relative humidity of air, but not sensitive to that of soil moisture. The error of estimation was resulted from Bowen ratios and atmospheric stability. Compared with the eddy covariance method, the error was within a reasonable range. As estimated by the two-wavelength method, the maximum daily and total evapotranspiration of the study area was 3.5 mm and 162.4 mm, respectively.

Effects of heterogeneous distribution of soil resources on the growth of Chinese fir seedlings under warming

JIANG Qi, CHEN Guang-shui, CHEN Ting-ting, ZHANG Li-hong, YAN Xiao-jun, XIONG De-cheng

2019, 30(7):  2156-2164.  doi:10.13287/j.1001-9332.201907.019

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A three-factor experiment with air temperature manipulation, soil temperature manipulation and nutrients distribution pattern was conducted in Forest Ecosystem and Global Change Research Station of Fujian Normal University in Chenda, Sanming, Fujian Province. We examined the effects of heterogeneous distribution of soil resources and warming on underground and aboveground growth of Chinese fir (Cunninghamia lanceolata) seedlings, and whether warming could change the recognition of fine roots to the heterogeneous distribution of soil resources, to understand the response of Chinese fir seedlings to heterogeneous distribution of soil resources under the background of global warming. The results showed that the recognition degree of Chinese fir to the nutrients distribution pattern was mainly reflected by the absorbing root (0-1 mm diameter class) rather than by the 1-2 mm diameter class fine roots. There were no significant effects of warming on the ratio of fine root biomass between nutrient-poor and nutrient-rich patches, the coefficient of nutrients-avoidance and the coefficient of nutrients-preference of fine roots of young Chinese fir except for the single air warming. Chinese fir had higher fine root biomass (0-1 mm diameter class) and lower height in the heterogeneous soil resource environment. Air warming decreased the biomass of fine roots (both 0-1 and 0-2 mm diameter classes) and increased the height of trees. Soil warming decreased the fine root biomass of 1-2 mm diameter class and increased the height of trees and the length of lateral branches. There was no significant interactive effect of air warming, soil warming and heterogeneity of soil resource on aboveground and belowground growth of Chinese fir. The results demonstrated that the absorbing roots of Chinese fir seedlings could recognize the heterogeneous distribution of soil resources,which was not altered by warming.

Responses of vegetation growth to temperature during 1982-2015 in Xinjiang, China.

DONG Lu, ZHAO Jie, LIU Xue-jia, DU Zi-qiang, WU Zhi-tao, ZHANG Hong

2019, 30(7):  2165-2170.  doi:10.13287/j.1001-9332.201907.023

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Combined with the normalized difference vegetation index (NDVI) dataset, vegetation type data, and meteorological data, we revealed the variation of vegetation growth responses to air temperature in the growing-season during 1982-2015 in Xinjiang, using the moving-windows based partial correlation analysis, the unitary linear regression analysis and GIS spatial analysis. Results showed that, in the whole growing-seasons of study period, there was a significant downturn trend in the responses of vegetation growth to temperature. At the seasonal scale, the downturn trend was obvious especially in summer and autumn, while it was in adverse in spring. During the whole gro-wing season, the responses of different vegetation types to air temperature change showed a decreasing trend. Seasonally, the responses of grassland and forest to temperature change showed a significant increase, while that of shrubland and desert were exactly the opposite in spring. The responses of all natural vegetation (grassland, shrubland, desert and forest) to temperature change showed a significant decreasing trend in summer, whereas their responses in autumn had no significant statistical characteristics. Spatially, the decreasing influence of temperature on the vegetation growth during the growing season in Xinjiang was universal, which might be due to the change in precipitation and solar radiation.

Leaf C:N:P stoichiometry of 67 plant species and its relations with climate factors across the deserts in Xinjiang, China.

HE Mao-song, LUO Yan, PENG Qing-wen, YANG Si-qi, LI Kai-hui, HAN Wen-xuan

2019, 30(7):  2171-2180.  doi:10.13287/j.1001-9332.201907.025

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Desert ecosystem has unique drought-enduring plants and stoichiometric characteristics. We collected leaf samples of 67 plant species from 63 desert sites in Xinjiang, and explored foliar carbon (C), nitrogen (N) and phosphorus (P) stoichiometry and the relationship between leaf nutrient stoichiometry and climatic factors. The results showed that the average content of leaf C, N and P in these plants were 394, 18.4 and 1.14 mg·g^-1, respectively. The mean values of C:N, C:P and N:P were 28, 419 and 18, respectively. In general, shrubs had higher leaf N content than trees and herbs, while leaf P content was lower (higher) in shrubs than in herbaceous plants (trees). Plants with C3 photosynthesis pathway had higher leaf C, N, C:P and N:P than those with C4 pathway. With increasing mean annual precipitation, leaf C first decreased and then increased, while both leaf N and P showed the opposite trend. Leaf C:N and C:P first decreased and then increased, while leaf N:P changed insignificantly. With increasing mean annual temperature, leaf C first decreased and then increased, and leaf N and P decreased, while leaf C:P and N:P increased. Leaf C:N did not change significantly with mean annual temperature. Mean annual precipitation generally showed stronger control on the variation of leaf nutrient stoichiometry than MAT and plant functional types. These results could help predict responses of the biogeochemical cycling of C, N and P to the global climate changes and provide reference and basic data for biogeochemical modeling in the arid regions.

Spatial and temporal variability of climatic potential productivity in Yunnan Province, China.

LI Zhen-jie, DUAN Chang-chun, JIN Li-li, HU Xue-qiong, LI Bin, YANG He-yan

2019, 30(7):  2181-2190.  doi:10.13287/j.1001-9332.201907.017

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We used the mean annual temperature and mean annual precipitation data during 1961 and 2017 of 101 national meteorological stations in Yunnan Province to calculate three climate-induced potential productivity in Yunnan Province by Miami model and the Thornthwaite Memorial model. The abrupt test was carried out by Mann-Kendell method. The spatial and temporal distribution characteristics and future trends of the three climate-induced potential productivities were analyzed. Results showed that the average values of the temperature potential productivity (Y_t), precipitation potential productivity (Y_r) and evapotranspiration potential productivity (Y_e) during the study period was 1968, 1477 and 1434 g·m^-2·a^-1, respectively. The value of Y_t was rising in Yunnan Province. For the value of Y_r /Y_t, there was a large difference in water-heat ratio among regions, as well as the binding conditions. There was an abrupt change in climate-induced potential productivity, with Y_t began to abrupt change significantly in 2001. There was no abrupt change in Y_r, but Y_e had abrupt change in 2002-2004. The spatial distribution of climate production potential and climate tendency were uneven. The annual average value of Y_t, Y_r and Y_e was 1030-2465, 927-2341 and 832-1995 g·m^-2·a^-1, respectively. The climate-induced potential productivity was the lowest in the northwestern and northeastern Yunnan and the highest in the southwestern and southern Yunnan. Most of the climatic propensity rates of Y_t, Y_r and Y_e showed increase, decrease and increase trends respectively. Eight schemes simulating future climate change (i.e., temperature increased by 1 ℃, precipitation increased by 10%, temperature decreased by 1 ℃, precipitation decreased by 10%, temperature increased by 1 ℃ and precipitation decreased by 10%, temperature increased by 1 ℃ and precipitation increased by 10%, the temperature decrease by 1 ℃ and the precipitation increased by 10%, the temperature decrease by 1 ℃ and precipitation decreased by 10%) would lead to Y_e changes of 6-45, 13-77.2, 15-67, -87 to -17, -74-46, 58-96, -54-57, -101 to -59 g·m^-2·a^-1, respectively. On the whole, if the climate tends to be “warm and wet” in the future, it will be beneficial for crop production. However, if it tends to be “cold and dry”, it will be unfavorable to crop production in the study area.

Stable isotopes characteristics of precipitation over Shaanxi-Gansu-Ningxia and its water vapor sources.

LIU Jie-yao, ZHANG Fu-ping, FENG Qi, WEI Yong-fen, HUANG Liang-hong, LI Zong-xing, NIE Shuo, LI Ling

2019, 30(7):  2191-2200.  doi:10.13287/j.1001-9332.201907.021

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Based on hydrogen and oxygen stable isotopes in precipitation and meteorological data over Shaanxi-Gansu-Ningxia provided by the Global Network of Isotopes in Precipitation (GNIP) and in previous literature, the spatial and temporal variations of oxygen stable isotopes in precipitation and their driving factors were analyzed, the local meteoric water line (LMWL) functions were established. The results showed that the slope and intercept of the LMWL changed in the order of Gansu<Shaanxi<Ningxia, with all of them being lower than slope and intercept of the Global Meteo-ric Water Line. The precipitation process of three provinces had been evaporated and fractionated to different degrees. The evaporation was enhanced along Ningxia, Shaanxi and Gansu. The δ¹⁸O value in precipitation in the Shaanxi-Gansu-Ningxia region was enriched in summer and autumn but poor in winter and spring. For the spatial distribution, the weighted δ¹⁸O value decreased from the northwest to the southeast. δ¹⁸O in precipitation showed significant temperature effect, but was no precipi-tation effect, reflecting the characteristics of continental climate in the middle and high latitudes. The quantitative relation of elevation effect was -0.12‰·(100 m)^-1, and latitude effect was more significant by -0.27‰ per °. The water vapor source was tracked by HYSPLIT model. The cluster trajectory of air masses showed that water vapor from the Bay of Bengal, southeast monsoon and westerly zone were the main sources in summer half year, while it mainly transported by the westerly belt in winter half year.

Responses of grassland ecosystem productivity to altered precipitation regime: A review.

GUO Qun

2019, 30(7):  2201-2210.  doi:10.13287/j.1001-9332.201907.024

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Under global change scenario, precipitation pattern has significantly changed, mainly in the aspects of annual precipitation amount, precipitation seasonal distribution and precipitation event characteristics (size of individual precipitation event, periods length between two precipitation events, and number of precipitation events in a year), which combined to affect various processes of terrestrial ecosystems, especially productivity. Grassland ecosystem is one of the most sensitive ecosystems to the changes of precipitation regime. Therefore, it is necessary to clarify the responses of productivity to altered precipitation regime in grasslands. In this study, I firstly reviewed the responses of grassland productivity to each characteristic of the altered precipitation regime. Then, I summarized the methods that employed in the study of productivity-precipitation relationship, including long-term observations, manipulative field experiments, and modelling. Finally, I came up with several theoretical and methodological problems that needed to be solved in the future. This work would facilitate the understanding of how grasslands response to the global climate change, with implications for grassland management in the context of climate change.

Relationship of plant abundance, air temperature and humidity with negative ions based on control experiment

LI Ai-bo, ZHAO Xiong-wei, LI Chun-you, ZHOU Ben-zhi, YANG Zhen-ya, ZHOU Pei-pei, ZHAO Ya-min

2019, 30(7):  2211-2217.  doi:10.13287/j.1001-9332.201907.016

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Previous studies on negative air ion (NAI), an important index for evaluating atmospheric quality, has been focused on field observation, and less on NAI under controlled condition. In this study, the NAI concentrations of different individual abundance of Liquidambar formosana and Taxus wallichiana were continuously monitored under the same climatic conditions in Hushan Experimental Base of Qianjiangyuan Forest Ecosystem Research Station, Zhejiang Province from September to October 2018. Changes of NAI concentration were monitored under different levels of air temperature and relative humidity to explore the effects of forest vegetation and meteorological factors on NAI. The results showed that both species significantly increased the NAI concentration. Plant abundance was positively correlated with the NAI concentration, and the relationship between them fitted the quadratic function with the plant abundance ranging from 0 to 50. The fitting equations for L. formosana and T. wallichiana were as follows: y=-0.0484x²+4.7005x+345.7 (R²=0.62), y=-0.0207x²+1.9189x+365.91 (R²=0.34). There was a significant positive correlation between NAI concentration and air temperature in the range of 5-30 ℃ with a fitting equation of y=0.4139x²-9.2229x+89.919 (R²=0.92). The NAI concentration and the relative humidity of air in the range of 56%-87% were positively correlated with a fitting equation of y=3.6508e^{0.0526x(R2=0.94).}

Original Articles

Comparing the responses of radial growth between Quercus mongolica and Phellodendron amurense to climate change in Xiaoxing’an Mountains, China.

HAN Jin-sheng, ZHAO Hui-ying, ZHU Liang-jun, ZHANG Yuan-dong, LI Zong-shan, WANG Xiao-chun

2019, 30(7):  2218-2230.  doi:10.13287/j.1001-9332.201907.012

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Quercus mongolica and Phellodendron amurense are two important broad-leaved species in temperate forests of Northeast China. It is critical to explore their responses to climate change for supporting management, protection, and restoration of the broad-leaved forest in Northeast China under the future climate change scenario. Three sampling sites along a longitude gradient, Heilun, Tieli and Yichun, were set up in the Xiaoxing’an Mountains. Dendrochronological methods were used to establish standard chronologies for Q. mongolica and P. amurense. Correlation analyses were conducted between these chronologies and local climatic factors to establish the spatial and temporal variations in growth-climate relationship of Q. mongolica and P. amurense. The results showed that the radial growth of P. amurense was sensitive to temperature, while that of Q. mongolica was limi-ted by both temperature and precipitation. The temperature sensitivities of these two species were different. High spring temperature inhibited the radial growth of Q. mongolica, but promoted that of P. amurense. The limiting effect of high maximum temperature in summer on radial growth of Q. mongolica was significantly higher than that of P. amurense. With the increases of longitude (water availability), the correlation coefficients between radial growth of Q. mongolica and precipitation gradually weakened, while P. amurense didn’t change. The physiological characteristics of those tree species was the key factors affecting their growth-climate relationship. With the significant warming since the 1976, the growth trend of P. amurense increased, whilst that of Q. mongolica decreased. Deteriorated drought stress caused by warming and difference in the species’ ability to cope with water deficits might be the main reasons for different responses of two species, and for the divergence phenomenon occurring for Q. mongolica. If warming continues or worsens in the future, the growth of Q. mongolica may decline due to the intensified drought stress, while that of P. amurense may be less affected or be slightly enhanced.

Responses of radial growth to climate change in Pinus massoniana at different altitudes and slopes.

QIAO Jing-jing, WANG Tong, PAN Lei, SUN Yu-jun

2019, 30(7):  2231-2240.  doi:10.13287/j.1001-9332.201907.011

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With dendrochronology method, standard and residual chronologies of Pinus massoniana were established at low altitude (260 m), middle altitude (460 m), high altitude (690 m), sunny slope (270 m), and shady slope (265 m). Relationships between the tree-ring width and the climatic factors were quantified using correlation analysis and redundancy analysis (RDA). The optimal multiple regression models for the radial growth of P. massoniana and the climatic factors were established. We analyzed the change rule of radial growth and its relationship with the climatic factors along with the altitude and slope. The results showed that the radial growth of P. massoniana was significantly affected by precipitation and temperature across the altitude gradient and the slope level, respectively. Among the 120 climatic variables, precipitation in December of last year and the extreme minimum temperature in February of current year had the most significant negative effects on the radial growth at different altitudes and slopes, respectively. This study quantitatively described the impacts of climate change on the radial growth of P. massoniana in the subtropical region, and provided a scientific basis for the planting and management of P. massoniana forest in Jiangle Country under the climate warming background.

Effects of species diversity and phylogenetic diversity on productivity of a mixed broadleaved-Korean pine forest.

CHE Ying, JIN Guang-ze

2019, 30(7):  2241-2248.  doi:10.13287/j.1001-9332.201907.010

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The relationship between biodiversity and ecosystem function is one of the hot spot in ecological research. The driving effect of plant diversity on forest productivity has been widely focused, but its underlying mechanisms are still controversial. We explored the impacts of species diversity and phylogenetic diversity on forest productivity at different spatial scales based on a 9 hm² forest dynamic monitoring plot of typical mixed broadleaved-Korean pine (Pinus koraiensis) forest in Liangshui National Nature Reserve, Heilongjiang Province, with the censuses data in 2005 and 2015, using linear regression and structural equation models. The results showed that species diversity and phylogenetic diversity were both positively correlated with productivity. The strength of species diversity on productivity gradually enhanced as spatial scales increased, while the effects of phylogenetic diversity on productivity showed opposite trend. On small scales, the effects of phylogenetic diversity on productivity was stronger than species diversity. Moreover, productivity was affected by abiotic factors. Soil factors were significantly positively correlated with productivity at different scales, which was gradually dominated as spatial scales increased. Our results indicated that evolutionary information should be considered in future ecosystem function studies, which might provide additional explanatory power for other diversity metrics. Meanwhile, the effects of spatial scales and abiotic factors should also be considered, which could provide a scientific basis for further understanding the mechanisms underlying the changes of forest productivity.

Impact of habitats on rodent-mediated seed fates of Quercus aliena var. acuteserrata.

KANG Hai-bin, WANG De-xiang, CHANG Ming-jie, KANG Bing, YU Fei, LIU Shu-tong

2019, 30(7):  2249-2256.  doi:10.13287/j.1001-9332.201907.004

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Disturbance is the driving force of forest succession, which can change forest structure and surface vegetation. Disturbance also affects rodent-mediated seed dispersal. In this study, numbered plastic tags were used to examine the responses of rodent dispersal behavior to the fates of Quercus aliena var. acuteserrata acorns at three habitats formed by different artificial disturbances in pine-oak mixed forests in the Qinling Mountains, i.e., unlogged stand, stand in the third year after tending thinning, and bare land. The results showed that seed removal rate from stands in the third year after tending was significantly higher than that in the other two habitats. The proportion of predation in bare land was significantly lower than that in the unlogged stand (25.0%) and in the stand in the third year after tending thinning (36.3%). In the third year after tending thinning, the seed predation rate after seed moving was significantly higher than those in the unlogged stand (17.3%) and bare land (5.0%). Moreover, the proportion of scatter hoarding after removal was also highest in the stand in the third year after tending thinning (4.3%). The longest average dispersal distance (26 m) occurred in the stand in the third year after tending thinning, which was significantly longer than those at the other two habitats. Therefore, the different habitat types significantly influenced the initial seed dispersal process by rodents, with consequences on the rates of seedling establishment. Habitat types affected the foraging strategies of rodents, thereby leading to different seed dispersal modes and natural regeneration patterns in the forest.

Effects of litter addition on the dynamics of soil humic substances during freeze-thaw events in a subalpine forest.

WEI Xin-yu, YANG Yu-lian, WU Fu-zhong, CHEN Zi-hao, CHEN Ya, DONG Yu-liang, ZHANG Li

2019, 30(7):  2257-2266.  doi:10.13287/j.1001-9332.201907.006

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During soil formation, the accumulation of humic substances such as humic acid and fulvic acid is an important way to maintain soil fertility and nutrient cycling, which is regulated by soil substrate quality, litter, and environmental factors. In a laboratory incubation experiment, we exa-mined the effects of litter addition on soil humic substances accumulation in freeze-thaw environment by controlling the freeze-thaw cycles and litter additions in soils from the typical coniferous forest, mixed forest and broadleaved forest in a subalpine forest in western Sichuan. The freeze-thaw events significantly increased the content of humic substances in the coniferous forest soils but decreased those in the mixed forest soil and broadleaved forest soil. Litter addition had no significant effect on the content of soil humic substances. Freeze-thaw events increased the content of humic acid, with the net accumulation of humic acid following the order of mixed forest > coniferous forest > broad-leaved forest. Freeze-thaw events decreased the content of fulvic acid in the three forest soils during the early stage of incubation, and the degree of fulvic acid degradation was broadleaved forest > mixed forest > coniferous forest. Litter addition had no significant effect on the content of soil humic acid and fulvic acid. With prolonged incubation, the content of humic acid and fulvic acid in the three types of forest soils all declined. These results indicated that litter had effects on soil humic substances, which were related to soil substrate quality and affected by the duration of soil freeze-thaw events in winter.

Changes of soil enzyme activities and nutrients across different succession stages of grazing alpine Kobresia grassland.

LI Qian, SUN Ya-nan, LIN Li, LI Yi-kang, DU Yan-gong, GUO Xiao-wei, YANG Yong-sheng, CAO Guang-min

2019, 30(7):  2267-2274.  doi:10.13287/j.1001-9332.201907.001

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The variation of soil enzyme activity and relevance with soil nutrients was examined in multistable grazing alpine Kobresia grassland, including Gramineae-Kobresia humilis community, K. humilis community, K. pygmaea community at thickened stage, K. pygmaea community at cracked stage and forb-black soil type secondary bare land. The results showed that the vegetation coverage and aboveground biomass successively decreased with degenerative succession. The belowground biomass was the highest in the K. pygmaea community at thickened and cracked stages. The activities of soil sucrase, urease, cellulase, alkaline phosphatase and aryl sulfatase were higher at the surface soil layer (0-10 cm) than those at the subsurface soil layer (10-20 cm), while the pattern of chitinase activity was contrary. The activities of cellulase, alkaline phosphatase and aryl sulfatase were the highest in the Gramineae-K. humilis community and the lowest at the forb-black soil type secondary bare land, and they slightly increased during the thickened stage of K. pygmaea community. Chitinase activity was relatively high at the middle three stages, while urease and sucrase activity had an obvious increase in the forb-black soil type secondary bare land. Soil moisture, ammonium, alkali-hydrolyzable nitrogen, total nitrogen, total carbon and organic carbon successively decreased with degenerative succession, whereas the concentrations of nitrate and available phosphorus increased at the latter two succession stages. The activities of the other enzymes, except for chitinase, were significantly positively correlated with the soil available phosphorus, ammonium, alkali-hydrolyzed nitrogen, total carbon, and organic carbon, and negatively correlated with soil pH. The activities of cellulose, alkaline phosphatase and aryl sulfatase were significantly positively correlated with soil moisture and total nitrogen. The main factors affecting soil enzyme activity were available phosphorus and ammonium. Soil enzymes showed different evolutionary trends influenced by grazing degradation succession in the alpine grassland, with a synergistic effect with soil nut-rients. Moreover, severely degraded extreme environments may stimulate soil enzyme activities related to nitrogen and carbon transformation.

The characteristics of decomposition and nutrient release of Vicia villosa under different fertilization treatments.

ZHANG Cheng-lan, LIU Chun-zeng, LI Ben-yin, ZHANG Meng, LYU Yu-hu, CHEN Xue-qing, CAO Wei-dong

2019, 30(7):  2275-2283.  doi:10.13287/j.1001-9332.201907.005

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The effects of three fertilization treatments (no fertilizer, nitrogen fertilizer, and lime) on the characteristics of Vicia villosa decomposition and nutrient release were studied using the nylon bag method in the fields. The results showed that the cumulative decomposition rate of V. villosa was 65.3%-72.5% across the three fertilization treatments. V. villosa decomposed rapidly during 0-11 d, then slowed down and tended to be stable. The nutrient release rates across the three treatments were potassium > phosphorus > carbon > nitrogen. At the end of the experiment (148 d), the cumulative release rates of carbon, nitrogen, phosphorus and potassium were 83.6%-84.6%, 78.2%-81.2%, 89.8%-91.4% and 96.3%-97.0%, respectively. During the whole decomposition period, the characteristics of nitrogen release and decomposition of V. villosa were similar. Compared with no fertilizer treatment, lime application promoted decomposition and release of nitrogen, phosphorus and potassium. Nitrogen fertilizer application promoted phosphorus release but inhibited potassium release. Both nitrogen application and lime application had no significant effect on carbon release. The application of nitrogen fertilizer promoted the decomposition of V. villosa and nitrogen release in 0-11 d, but inhibited those processes in 11-148 d. The first-order kinetic reaction equation and logarithmic function equation well fitted the characteristics of V. villosa decomposition and the release of carbon, nitrogen, phosphorus and potassium in the rice fields of South Henan. The characteristic parameters of the equation were significantly correlated with the decomposition rate and nutrient release rate of V. villosa. In summary, lime application was better than nitrogen fertili-zer in promoting decomposition and nutrient release of V. villosa. Moreover, the parameters of the first-order kinetic equation and logarithmic function equation showed a good description of decomposition and nutrient release of V. villosa.

Effects of urban nighttime light on the growth of Cinnamomum camphora

LI Xiao-ting, CHEN Bin, WANG Hai-jun, ZHENG Guang, YANG Dan, MIAO Xin-yu, XU Chi

2019, 30(7):  2284-2290.  doi:10.13287/j.1001-9332.201907.009

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To understand the effects of urban artificial nighttime light on the growth of evergreen trees, we conducted a field investigation in a typical urban street planted with Cinnamomum camphora (a common evergreen street tree species in eastern China) in the Nanjing City, China. Along the street, trees from two types of growing locations with contrasting distances from the street lamp (just under the lamp vs. between two adjacent lamps) were selected. The growth-related plant functional traits were measured and compared. The results showed that trees grown under the lamp had a mean diameter at beast height (DBH) of 16.8 cm, current-year branch productivity (CBP) of 309.4 g·m^-2, current-year leaf productivity (CLP) of 241.5 g·m^-2, and leaf relative chlorophyll content (LCC) of 34.6 SPAD. Trees grown between lamps had a mean DBH of 15.5 cm, CBP of 273.4 g·m^-2, CLP of 212.8 g·m^-2, and LCC of 33.1 SPAD. DBH, CBP, CLP and LCC of the trees under the lamp were significantly higher than those between lamps. There was no significant difference in specific leaf area between trees from the two locations. Our results suggested that urban artificial nighttime light could promote the growth of C. camphora, and alter sunlight-determined characteristics of canopy growth vigor.

Geographical distribution and bioclimatic characteristics of the wild Gentiana rigescens resources.

SHEN Tao, YU Hong, WANG Yuan-zhong

2019, 30(7):  2291-2300.  doi:10.13287/j.1001-9332.201907.003

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Based on the species distribution data provided by the National Specimen Information Infrastructure combined with field survey and MaxEnt model, we simulated and verified the suitable distribution area of Gentiana rigescens. Furthermore, the relationship between the geographical distribution and climatic factors of G. rigescens was analyzed. The results showed that area under curve of training set and test set were more than 0.90, indicating high prediction precision and accurate prediction results. Geographic coordinate range of G. rigescens were 22.2°—28.75° N and 98.48°—110.59° E. The suitable altitude range was from 1830 to 1959 m. The total area of suitable distribution region was 63.92×10⁴ km², including the most suitable distribution region (4.33×10⁴ km²) and middle suitable distribution region (21.42×10⁴ km²). Total area of suitable distribution region in Yunnan, Guizhou and Sichuan provinces was about 59.10×10⁴ km², which accounted for 92.46% of total suitable distribution region in China. Solar radiation (March, June and August), temperature annual range, mean temperature of warmest quarter, mean precipitation of October and November, precipitation of driest quarter were the major climatic factors influencing the geographi-cal distribution of G. rigescens. Results from partial least squares regression analysis showed that solar radiation (March, June and August), temperature annual range, mean precipitation of October and November, precipitation of driest quarter were the main restriction factors in north and east of suitable distribution region. The main restriction factors in south of suitable distribution region were solar radiation of June, mean temperature of warmest quarter, precipitation of October and November. The factors limiting distribution of G. rigescens to basin of Sichuan and Guangxi were solar radiation, temperature annual range, mean temperature of warmest quarter, annual biotempe-rature and annual potential evapotranspiration. In conclusion, suitable distribution region of G. rigescens primarily located in the Yunnan-Guizhou Plateau, where subtropical humid climate was most suitable for its growth.

Pollen in surface soil at the southern slope of western Tianshan, China.

YAO Fu-long, XIA Qian-qian, ZHANG Jing, YANG Hai-jun

2019, 30(7):  2301-2308.  doi:10.13287/j.1001-9332.201907.013

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We analyzed 52 pollen samples of surface soils from the southern slope of western Tian-shan, China, to understand the relationship between the surface pollen and modern vegetation, and the significance of the Artemisia/Chenopodiaceae (A/C). The results showed that there were five vegetation zones from the mountain top to the foot, i.e., alpine desert zone, alpine meadow zone, meadow and steppe zone, mountain desert zone, and typical desert zone. The typical taxa were Artemisia, Chenopodiaceae, Poaceae and Ephedra. The surface pollen assemblages greatly differed across different vegetation zones in this area. Surface pollen in the southern slope of the western Tianshan Mountains was affected by the northern slope, with the impacts increasing with the increases of altitude. The A/C increased with altitude, peaked in the alpine meadow zone, and then decreased, which could effectively indicate the vertical moisture change. Given the great fluctuation of A/C value, when using this ratio to reconstruct climate and environment, attention should be paid to the fact that high values caused by human activities and other factors may lead to misjudgments.

Spatial-temporal dynamics of grassland NPP and its driving factors in the Loess Plateau, China

LIU Yang-yang, WANG Qian, YANG Yue, GANG Cheng-cheng, ZHANG Zhao-ying, TONG Lin-jing, LI Jian-long

2019, 30(7):  2309-2319.  doi:10.13287/j.1001-9332.201907.002

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We estimated grassland NPP using CASA model in the Loess Plateau during 2000-2015 and further analyzed the spatiotemporal dynamics, stability and persistence of grassland NPP. The driving factors of grassland NPP were analyzed from four aspects, i.e., vegetation types, topographic factors, climate change, and human activities. The results showed that the average NPP was 202.93 g C·m^-2·a^-1. The grassland NPP showed an increasing trend with an average increase rate of 2.43 g C·m^-2·a^-1. The distribution of NPP in grassland had obvious spatial heterogeneity, which was generally high in the south and low in the north. 91.2% of the total grassland area showed an increasing trend, mainly distributed in most areas of Shaanxi Province, Longdong and Longzhong areas of Gansu Province, and most parts of Qinghai Province. The regions with a stable growth condition of grassland NPP mainly located in the south of Ordos, northern Shaanxi, and Gansu. The future change trend of grassland NPP would be consistent with that of the past in most areas. The grassland NPP would continue to increase in most areas of Shaanxi Province, Longzhong and Longdong areas in Gansu Province. The average NPP of slope grassland was 703.37 g C·m^-2·a^-1, while that of alpine and subalpine grassland was 57.28 g C·m^-2·a^-1. The grassland NPP was higher in high altitude area and relative low in plain and hilly area. The increased precipitation promoted the increase of grassland NPP during the study period. Human activities such as improvement of overgrazing and returning cropland to grassland also played an important role in the increase of grassland NPP in the Loess Plateau.

Leaf functional traits and nutrient resorption among major silviculture tree species in coastal sandy site.

ZHOU Li-li, QIAN Rui-ling, LI Shu-bin, DONG Bo-wei, CHEN Bao-ying, PAN Hui

2019, 30(7):  2320-2328.  doi:10.13287/j.1001-9332.201907.007

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To understand the adaptative strategies of different tree species to drought and nutrient-deficient environment in coastal sandy site, leaf functional traits and nutrient resorption of four major silviculture tree species, i.e., Casuarina equisetifolia, Pinus elliottii, Acasia crassicarpa and Eucalyptus urophylla × E. grandis were analyzed. Leaf area and specific leaf area of coniferous species (C. equisetifolia and P. elliottii) were significantly lower, and leaf dry matter content and leaf thickness were significantly higher than those of broadleaved species (A. crassicarpa and E. urophy-lla × E. grandis). Nitrogen and P contents of mature leaf and leaf litter in broadleaved species were higher than those in coniferous species. Nitrogen and P contents of mature leaf were higher than those in leaf litter, but N:P was lower than that in leaf litter. Nitrogen and P resorption efficiencies were higher in coniferous species than those in broadleaved species. The P resorption efficiency in all species was significantly higher than N resorption efficiency. The N resorption efficiency of C. equisetifolia, P. elliottii, A. crassicarpa and E. urophylla × E. grandis was 64.2%, 63.1%, 47.0% and 16.8%, and the P resorption efficiency was 92.5%, 81.6%, 80.3% and 18.0%, respectively. The specific leaf area was significantly positively correlated with leaf N and P contents, but negatively correlated with leaf dry matter content, leaf thickness, and nutrient resorption efficiency. Leaf dry matter content was significantly positively correlated with leaf thickness and nutrient resorption efficiency. Therefore, C. equisetifolia and P. elliottii belonged to slow investment species with a higher nutrient resorption efficiency, while A. crassicarpa and E. urophylla × E. grandis belonged to fast investment species with lower nutrient resorption efficiency. Different tree species developed different adaptive strategies to coastal sandy environments through the interactions between leaf functional traits and nutrient resorption.

Potential distribution of Spartinal alterniflora in China coastal areas based on Maxent niche model

ZHANG Dan-hua, HU Yuan-man, LIU-Miao

2019, 30(7):  2329-2337.  doi:10.13287/j.1001-9332.201907.014

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Maxent niche model was used to project the potential distribution of alien plant species Spartina alterniflora in China, with 96 S. alterniflora records and marine and climatic data along China coastal area. The results showed that suitable area for the distribution of S. alterniflora occupied 85% of coastal areas, with the highly suitable area, the medium, and low suitable area accounting for 18%, 34% and 33%, respectively. Only 15% of the coastal areas were regions with distribution possibility of less than 5%. Its distribution suitability was mainly related to annual lowest seawater temperature, annual mean seawater temperature, annual mean air temperature, and annual lowest temperature in January. However, the importance of annual mean precipitation, annual mean daily diurnal range, seawater salinity, annual highest seawater temperature, annual highest tempe-rature in June and current velocity was relatively small. At the highly suitable areas for S. alterni-flora, the annual lowest seawater temperature ranged from 0.62 to 24.81 ℃, the annual mean seawater temperature ranged from 10.46 to 27.29 ℃, the annual mean air temperature was between 9 to 25 ℃, and the annual lowest temperature in January was between -13.5 and 16.7 ℃. The distribution possibility of S. alterniflora in the northern coastal area was over 20%, indicating it has a great potential to invade further north in China, especially in Bohai Bay areas. According to the current distribution records and climatic data in China, the invasion risk of S. alterniflora in central and southern coasts of Hainan and most regions of Taiwan Province was low, but the possibility of future invasion can not be excluded.

Screening of extreme salt-alkali tolerant strain and effect of its fertilizer on wheat growth and soil environment under saline-alkali condition.

ZHU Hao, LIU Ke-xin, LIU Wei-wei, CHI Xiao-li, ZHANG Xiao, XU Chao, JIN Xiao, SUN Zhong-tao, LIU Li-ying

2019, 30(7):  2338-2344.  doi:10.13287/j.1001-9332.201907.039

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To obtain salt-alkali tolerant strains which could be potenially used to improve the quality of saline-alkali soil, soil samples collected from Dongying, Shandong Province were diluted and spread to modified Gibbson medium with pH 9 and salt concentration of 100 g·L^-1. A total of 18 bacteria strains were obtained. By increasing salt concentration and pH, an extremely salt-alkali tole-rant strain N14 was screened which could grow at pH 12 and salt concentration of 20%. We analyzed the morphological, physiological and biochemical characters and 16S rDNA sequence of N14. The strain N14 was identified as Bacillus marmarensis. N14 bacterial fertilizer significantly increased the biomass of wheat, improved shoot height, fresh weight and dry weight by 21.8%, 57.9% and 41.7%, respectively. The addition of N14 bacterial fertilizer significantly increased the chlorophyll a, chlorophyll b and total chlorophyll in wheat by 36.4%, 20.0% and 31.7%, respectively. It significantly increased the activities of invertase, urease and alkaline phosphatase in saline-alkali soil by 23.2%, 68.8% and 106.5%, respectively. It also significantly increased the activities of superoxide dismutase, peroxidase and catalase in roots by 109.6%, 17.8% and 50%, respectively. The concentration of malondialdehyde in wheat roots was significantly reduced by 39.8%. This study provided an idea for the application of extreme salt-alkali tolerant bacteria and a way for improvement of saline-alkali soil.

Difference of the microbial community structure in the rhizosphere of soybean and oilseed rape based on high-throughput pyrosequencing analysis.

YANG Xiao-xiang, ZHANG Lei, HUANG Xiao-qin, WU Wen-xian, ZHOU Xi-quan, DU Lei, LI Huai-zhong, LIU Yong

2019, 30(7):  2345-2351.  doi:10.13287/j.1001-9332.201907.028

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Clubroot, caused by the soil-borne obligate pathogen Plasmodiophora brassicae, is one of the most severe disease in cruciferous crops. Previous studies showed that when oilseed rape was planted after soybean (namely soybean-oilseed rotation), the incidence and severity of clubroot of oilseed rape could be significantly reduced, compared with that with oilseed rape-oilseed rape conti-nuous cropping. Therefore, the soybean-oilseed rape rotation is a good way to suppress clubroot of oilseed rape. In this study, we compared the rhizosphere microbiome of soybean and oilseed rape rhizosphere soil collected from the field by 16S rRNA (for identification of prokaryotes) and the internal transcribed spacer (ITS) (for identification of fungi) sequencing. The results showed that both soybean and oilseed rape rhizosphere soils had Proteobacteria, Bacteroidetes, Acidobacteria, Actinobacteria, Ascomycota, Zygomycota, Basidiomycota and Chytridiomycota. Many microbial genera (e.g., Flavobacterium, Sphingomonas, Bacillus, Streptomyces, Pseudomonas, Trichoderma and Coniothyrium) with activities of biological control and plant growth promotion were more abundant in soybean rhizosphere soil than in the oilseed rape rhizosphere soil. The abundance of plant pathogenic bacteria and fungi was higher in the oilseed rape rhizosphere soil than in the soybean rhizosphere soil. Moreover, the soybean rhizosphere soil was enriched with Rhizobium, Bradyrhizobium (both for nitrogen fixation), and arbuscular mycorrhizal fungus (Glomus). These results indicated that soybean rhizosphere soil could promote the growth and proliferation of beneficial microorga-nisms, but inhibit that of plant pathogens. Our results provide evidence for explanation of the effectiveness of soybean-oilseed rape rotation to control clubroot of oilseed rape and provide potential bio-control resources for clubroot prevention.

Spatial planning of Qingyun Mountain scenic spot in Benxi, Northeast China based on ecological sensitivity assessment.

ZHAN Ming-song, ZHU Jing-hai

2019, 30(7):  2352-2360.  doi:10.13287/j.1001-9332.201907.037

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The ecological environment protection and utilization of forestland scenic spot is fundamental for the development of scenic spot tourism. In this study, an ecological sensitivity evaluation index system was established based on environmental factors and protection needs. The combined weights were obtained by using analytic hierarchy process (AHP) and entropy weight methods. The ecological sensitivity of the Qingyun Mountain scenic spot in Benxi was evaluated by GIS technique, and the spatial planning of the scenic spot was formulated. The results showed that the high-sensitive, sensitive, low-sensitive and non-sensitive areas accounted for 9.2%, 60.2%, 22.7% and 7.9% of the total area of Qingyun Mountain scenic spot, respectively. According to the ecological characteristics and ecological protection red line of Qingyun Mountain, the scenic area could be divided into three parts, including restricted development zone, moderate development zone, and tourism development zone. Combined with the spatial distribution of natural and cultural resources, the spatial planning of “two axis and six areas” in the scenic spot was formulated. In view of the resource utilization status and existing problems in each zone, we proposed corresponding tourism development planning strategies. Our results could provide a more scientific and effective planning path for the spatial planning of forestland scenic spots.

Spatial-temporal evolution characteristics and influencing factors of county-scale environmental pollution in Jilin Province, Northeast China

LI Lian-gang, ZHANG Ping-yu, LIU Wen-xin, LI Jing, WANG Lin-feng

2019, 30(7):  2361-2370.  doi:10.13287/j.1001-9332.201907.031

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Based on pollutant emissions and social-economic data during 2011 and 2015, we selec-ted the total emission index of four pollutants, including the industrial source, agricultural source, and urban living source. The comprehensive index of environmental pollution and sub-source pollution index were built to reflect the pollution of Jilin Province at county scale. Furthermore, the Moran’s I, spatial-temporal transition analysis, and standard deviation ellipse analysis were used to quantitatively examine the spatial-temporal evolutionary characteristics of environmental pollution in Jilin Province. A spatial econometric model was built to analyze the influencing factors of environmental pollution. The results showed that environmental pollution in Jilin Province presented spatial agglomeration characteristics, which was mainly concentrating in central areas such as Changchun and Jilin cities. There were obvious regional differences in the spatial distribution of environmental pollution from different sources. There were spatial correlation of the total environmental pollution and agricultural source pollution separately at county scale in Jilin Province. The correlation structure stability of the spatial distribution of environmental pollution was high, which had path locking characteristic. The spatial distribution of environmental pollution showed a northwest-southeast distribution pattern and a spread from the center to the surroundings. The barycenter of environmental pollution moved in the area between 43.65-43.66° N and 125.83-125.84° E. The level of regional economic development, urbanization level and agricultural production were main driving factors for county-scale environmental pollution and industrial source pollution. The adjustment and optimization of industrial structure had improved the overall environmental pollution and industrial source pollution situation. Overuse of chemical fertilizers significantly increased agricultural source pollution. The level of economic development and urbanization were the main drivers of urban living source pollution. The overall environmental pollution and agricultural source pollution had spatial diffusion effects, and their pollution status was closely related to the overall environmental pollution and agricultural source pollution status in adjacent areas, respectively.

Spatial pattern and evolutionary trend of sustainable development index of crop-livestock system: A case study in Shandong Province, China.

LI Yang, SUN Zhi-gang, ZHANG Xu-bo, YANG Jing-chao, HANG Sheng, LI Shi-ji, ZHU Wan-xue, LYU Yun, OUYANG Zhu

2019, 30(7):  2371-2383.  doi:10.13287/j.1001-9332.201907.020

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The intensification and industrialization of agricultural production leads to more and more serious separation of crop and livestock, which causes serious contradiction between livestock excrement and environment, and major challenges for agricultural sustainable development. Here, we quantitatively investigated the spatial pattern and evolutionary trend of the sustainable development index (ESI) of the crop-livestock system using the emergy analysis and the input/output data in Shandong Province (1999-2015). The results showed that the sustainability of the crop-livestock system in Shandong Province decreased from 1999 to 2015 by 22.0%. The net emergy yield ratio (EYR), environmental load ratio (ELR), and the benefits of unit economic inputs significantly increased. The environmental pressure from the crop and livestock production increased obviously, which was closely related to the increase of industrial resources input including electricity, compound fertilizer, and agricultural machinery. There were differences in the sustainable development level of the crop-livestock system among administrative prefectures in Shandong Province. The ESI level of crop-livestock system in most regions was relatively high, while that in the coastal regions (e.g., Weihai, Yantai) and industrial region (e.g., Zibo) was relatively low. The trends of the sustainable development of crop-livestock system varied in different cities. The sustainability of central and southern Shandong was decreasing, while that of northern Shandong was increasing year by year. In 2015, the ESI of the expected crop-livestock system (100% livestock manure replaced fertilizer) could reach 8.4, which was 2.6 times of that of the current crop-livestock system (30% livestock manure replaced fertilizer).

Screening, identification, and phosphate solubilizing characteristics of a new efficient phosphate solubilizing fungus

LI Dou-dou, SHANG Shuang-hua, HAN Wei, FANG Na-na, YI Yan-li

2019, 30(7):  2384-2392.  doi:10.13287/j.1001-9332.201907.033

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A phosphate solubilizing fungus was isolated from the rhizosphere of tomato in greenhouse in Liaozhong County, Liaoning Province, Northeast China. The strain was identified as a new strain of Penicillium oxalicum by morphological characteristics and ITS rDNA sequence comparison, and then was named PSF1. Strain PSF1 could utilize various carbon sources such as glucose, sucrose, lactose, galactose, soluble starch and nitrogen sources such as ammonium sulfate, ammonium chloride, ammonium nitrate, potassium nitrate, urea for growth and metabolism, with an efficient phosphate solubilizing capacity. It grew well and had a high ability of phosphate solubilization under the conditions of C/N 10:1-60:1 and initial pH 7-8. Strain PSF1 had strong acid production ability, with the pH of culture mediums decreasing from 7.00-7.50 to 2.06-4.87 during the culture process. The highest phosphate solubilizing capacity in four phosphorus sources mediums was tricalcium phosphate (869.62 mg·L^-1) > phosphate rock power (233.56 mg·L^-1) > aluminum phosphate (44.77 mg·L^-1) > iron phosphate (28.42 mg·L^-1). Results from Pearson correlation analysis showed that there were significant negative correlations between the changes of phosphate solubili-zing capacity and pH in tricalcium phosphate, phosphate rock power and iron phosphate mediums, but no significant correlation in aluminum phosphate medium. Strain PSF1 had strong phosphate solu-bilizing capacity and wide growing conditions, thus would have strong phosphate solubilizing capacity in soil.

Community characteristics of polyphosphate accummulating organisms in the heart sediment of three reservoirs in Fujian Province, China.

SHE Chen-xing, WANG Jing, SU Yu-ping, LIN Wan-zhen, LAN Rui-fang, LIU Jian-xi, LIN Jia

2019, 30(7):  2393-2403.  doi:10.13287/j.1001-9332.201907.026

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Polyphosphate accummulating organisms (PAOs) play an important role in the phosphorus metabolic cycling in the sediment of reservoir. We assessed the diversity and community structure of PAOs in the sediments by T-RFLP and clone sequencing which targeted ppk1 gene at the hearts of three reservoirs (Jiulongjiangxipi reservoir, Sanshiliujiao lake reservoir and Dongyaxi reservoir) in Fujian Province. The results showed that the diversity of PAOs varied among different reservoirs, though not statistically significant. The diversity of PAOs in the Sanshiliujiao lake reservoir was highest (Shannon index H=2.89±0.03, Simpson index D=0.06±0.01). The community structure of the PAOs in the Sanshiliujiao lake reservoir was most complicated, consistent with the results of the T-RFLP. The differences of dominant PAOs genera in three reservoirs were distinct, mainly concentrated in the Proteobacteria, Actinobacteria and Acidobacteria. The percentage of those three phylum accounted for 74.5%, 85.0% and 75.0%, respectively, of the total PAOs. The dominant groups in each reservoir sediment were Anaeromyxobacter and Solibacter. Various forms of phosphorus had certain influence on the diversity of PAOs. There were significantly correlation between Fe/Al-P and PAOs diversity and community structure. The dominant genus in the three reservoirs, Anaeromyxobacter, was positively correlated with all forms of phosphorus and significantly correlated with insoluble phosphorus such as OP and Ca-P, while Solibacter was negatively correlated with all forms of phosphorus. The results suggested that PAOs had important impacts on the phosphorus cycle of sediment in eutrophicatied reservoirs.

Spatial dstribution of the net anthropogenic phosphorus input (NAPI) to the Dongting Lake basin, China.

LIU Yan-ping, XIAO Ya-qian, ZHANG Ying

2019, 30(7):  2404-2414.  doi:10.13287/j.1001-9332.201907.032

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Based on the net anthropogenic phosphorus input (NAPI) model, we estimated the NAPI of the Dongting Lake basin and its sub-basins from 1985 to 2015, and analyzed the spatio-temporal distributions and variations. The results showed that there was an increasing trend at first and then a decrease in the Dongting Lake basin. The NAPI values in the area in 1985, 1995, 2005 and 2015 were 7.00, 9.20, 10.33, 10.01 kg·hm^-2·a^-1, respectively. The largest input source changed from the net food and feed import in 1985 to phosphorus fertilizer during 1995-2015. The mean annual input of phosphorus fertilizer, with an average value of 6.01 kg·hm^-2·a^-1 accounting for 65.8% of NAPI; followed by the food and feed import, the annual average value was 2.65 kg·hm^-2·a^-1, accounting for 29.0%, and the least was non-food phosphorus, with an average annual value of 0.47 kg·hm^-2·a^-1, accounting for 5.2%. Spatially, the distribution of NAPI in the Dongting Lake basin showed the characteristics of high in the northeast region and low in the west, which was mainly consistent with distribution of local agriculture. The average annual NAPI values in sub-basin from high to low ranked as following: Dongting Lake area, Xiangjiang River downstream, Zijiang River upstream, Xiangjiang River upstream, Lishui River area, Yuanjiang River upstream, Yuanjiang River downstream and Zijiang River downstream. The highest NAPI was found in the Dongting Lake area, increasing from 13.01 kg·hm^-2·a^-1 in 1985 to 24.14 kg·hm^-2·a^-1 in 2015. Agricultural production and population growth were the main contributors to the current input of net phosphorus, and the negative ecological effects of which could not be ignored.

Assessment of heavy metal bioaccumulation in food web of the coastal waters of Jiangsu Province, China, based on stable isotope values (δ¹³C and δ¹⁵N).

LI Yun-kai, ZHANG Rui, ZHANG Shuo, ZHANG Hu

2019, 30(7):  2415-2425.  doi:10.13287/j.1001-9332.201907.029

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The coastal waters in Jiangsu Province have always been an important fishery base since ancient time. In recent years, with the development of the industry in coastal cities, heavy metal pollution is becoming serious in Jiangsu Province. However, the bioaccumulation of heavy metals in the coastal food web is still unclear. In this study, we collected samples (including macroalgae, bivalves, cephalopods, gastropods, crustaceans and fish) through fishery resources survey in the coastal waters of Jiangsu in May 2017 and quantified the main ways of the material circulation and energy flows by constructing the food web using stable carbon and nitrogen isotopes. In addition, the bioaccumulation patterns of eight elements (seven heavy metals and 1 metalloid) through the food chains were investigated. The results showed that there were two energy pathways in this offshore ecosystem: the planktonic food-chain and the benthic food-chain, with Scapharca subcrenata and Phalium strigatum as the primary consumers, respectively. The benthic food-chain was the dominant food chain in energy recycling. The mean concentration of heavy metals from high to low in orga-nisms were Zn, Cu, As, Cd, Cr, Pb, Ni and Hg. The highest concentrations of elements were found in bivalves and the lowest ones in fish. The concentration of As in most species, the levels of Cd in bivalves and Oratosquilla oratoria, the Cr in Coilia mystus and the Zn, Cu, Cr in Ostrea denselamellosa exceeded the proposed health advisory levels. Regarding the bioaccumulation, a decrease in the concentration levels of Zn, Cd and Ni were observed along the planktonic food-chain and a significant positive correlation between Hg and trophic position were found across the benthic food-chain. Other elements had no significant change.

Probability distribution characteristics of stock density in offshore of northern South China Sea.

CAI Yan-cong, HUANG Zi-rong, XU You-wei, SUN Ming-shuai, XU Shan-nan, ZHANG Kui, CHEN Zuo-zhi

2019, 30(7):  2426-2436.  doi:10.13287/j.1001-9332.201907.015

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Based on catch data from the bottom trawl survey by eight cruises in offshore of northern South China Sea during 2014-2017, we analyzed the stock density distribution and explored its probability distribution with statistical method, which was further used to estimate the mean stock density in this region. The results showed that the coefficient of variation (CV) for stock density ranged from 0.67 to 1.03 for all the periods, indicating a highly uneven spatial distribution of stock density. The frequency distribution of fishery resource density was characterized by obvious right-skewed, which was dominated by stock density of 0-1000 kg·km^-2. The results of one sample Kolmogorov-Smirnov test indicated that three probability distribution patterns were suitable for stock density in this region, including Lognormal, Gamma and Weibull distributions. In terms of the mean stock density estimation, the values from Lognormal showed no statistically significant difference from those from others, but the opposite result was obtained between Gamma and Weibull distributions. Compared with 1960s-1970s, the appropriate probability distribution pattern of stock density has changed from single to multiple types. Variation of the proportion of low catch resulted from the changes in the structure of fishery resources, fishing effort and climate change might cause the alte-ration of probability distribution.

Population resources and fishery management policies of Schizopygopsis younghusbandi in the Yarlung Zangbo River, China.

SHAO Jian, MA Bao-shan, DUAN You-jian, XIE Cong-xin, LIN Shao-qing, ZHOU Xian-jun, HUO Bin

2019, 30(7):  2437-2446.  doi:10.13287/j.1001-9332.201907.030

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Schizopygopsis younghusbandi, an endemic species in China, is threatened by overfi-shing and biological invasion. With 694 individuals collected during August 2008 to August 2009 from the Xietongmen to Nimu of Yarlung Zangbo River, Tibet, the population resources and fishery management policies of the fish were studied using per-recruit models. The total instantaneous annual mortality (Z) of S. younghusbandi was 0.81 year^-1 for females and 0.78 year^-1 for males. The range of natural mortality (M) of females and males were 0.17-0.27 year^-1 and 0.21-0.33 year^-1, respectively. The range of current fishing mortality (F_cur) was 0.54-0.64 year^-1 for females and 0.45-0.57 year^-1 for males. The range of spawning potential ratio of S. younghusbandi was 10.1%-17.9% for females, being significantly lower than the threshold reference point (F_25%). That for males was 28.3%-43.6%, with 22.3% of which was higher than the target reference point (F_40%). This result indicated that the stock of S. younghusbandi had been over-exploited under the current fishery management policy. To evaluate the protective effects of capture age and seasonal closure, 14 different fishery management policies were simulated. The results showed that the stock of S. younghusbandi would be effectively conserved by enhancing the capture age to not less than 10 years old or setting the seasonal closure from February to June.

Carbon dioxide fluxes at the water-air interface and the main influencing factors from diffe-rent aquaculture systems of Sebastes schlegelii and Chlamys farreri

ZHANG Dong-xu, TIAN Xiang-li, DONG Shuang-lin, WANG Ming-yang, LIU Long-zhen

2019, 30(7):  2447-2456.  doi:10.13287/j.1001-9332.201907.035

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The static chamber-gas chromatography method was applied to observe CO₂ fluxes across the water-air interface from different aquaculture systems, including four groups of mesocosms, i.e., blank control system (CK), monoculture system of Sebastes schlegelii (F), monoculture system of Chlamys farreri (B) and polyculture system of S. schlegelii and C. farreri (FB). Meanwhile, the physical, chemical and biological indices of the water were measured. The results showed that the group CK was a stable CO₂ source, with the mean flux of 12.42 mg·m^-2·h^-1. The group B was a CO₂ source during the early and middle periods of the experiment and a CO₂ sink at the end of the experiment, with the mean flux during the experiment being 10.95 mg·m^-2·h^-1. The change trends of CO₂ flux in the group F and FB were generally consistent, acting as CO₂ sources in the early period and as CO₂ sinks subsequently. The mean fluxes of those two groups during the expe-riment were -3.53 and -10.49 mg·m^-2·h^-1, respectively. Water pH was a good predictor for CO₂ flux across the water-air interface according to the result of regression analysis, with pH value of 8.25 as the critical threshold between efflux and influx. The net primary production of water column was the main factor influencing the CO₂ flux, indicating that phytoplankton might be the main internal force regulating the CO₂ flux across the water-air interface. Our results indicated that C. farreri at present stocking density in the polyculture system could promote phytoplankton biomass as well as primary production and therefore enhance the CO₂ sink function.

Potential habitat and priority protection area of cranes with climate change in the Great Xing’an Mountains, China

JIANG Li-hua, GAO Jun-qin, WAN Ji-zhong

2019, 30(7):  2457-2469.  doi:10.13287/j.1001-9332.201907.040

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To clarify the impacts of climate change on the potential distribution of six crane species in the Great Xing’an Mountains region, and promote the effective protection of these species, we selected key environmental variables such as climate, topography, and vegetation type based on Pearson correlation and Jackknife analysis, and modeled the potential distribution of six crane species in the Great Xing’an Mountains using MaxEnt with the current and the future climate change scenarios (RCP4.5 and RCP8.5). We identified the priority protection areas (PPAs) and the target PPAs by zonation and ArcGIS. The results showed that with the current climate condition, the sui-table habitats of these species were mainly distributed in the central and the northwest part of the Great Xing’an Mountains. With RCP4.5 and RCP8.5 scenarios, the suitable habitats of Grus monacha, Grus japonensis, Grus vipio, Grus grus and Anthropoides virgo would decrease, while that of Grus leucogeranus would expand by 5.4%-6.3%. With current and the future climate change scenarios, the PPAs of these species were mainly distributed in the northwest, southeast and west-central parts of the Great Xing’an Mountains. The protect rate could reach about 20.1%-23.8% of the target PPAs conserved by protected areas (PAs). The protection gaps were mainly distributed in the west of Mohe County, the north-central of Ergun, the central and east of Genhe, the northeast of Yakeshi, and the south of Oroqen Autonomous Banner. We proposed to expand PAs to provide a strong guarantee for the effective protection of cranes species.

Reviews

Effects of long-term fertilization and water addition on soil properties and plant community characteristics in a semiarid grassland.

JIANG Yong, XU Zhu-wen, WANG Ru-zhen, LI Hui, ZHANG Yu-ge

2019, 30(7):  2470-2480.  doi:10.13287/j.1001-9332.201907.034

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We summarized the effects of fertilization and water addition on some soil properties and plant community characteristics in a long-term field experiment established in 2005 in a degraded grassland in Duolun, Inner Mongolia, China. The results showed that nitrogen (N) addition resulted in surface soil acidification and decreased acid buffering capacity, increased the availability of carbon (C), N, phosphorus (P), sulfur (S) and DTPA-extractable iron (Fe), manganese (Mn), and copper (Cu) contents, depleted the sum of base cations calcium (Ca), magnesium (Mg), potassium (K) and sodium (Na), decreased the diversity of soil microbial community. Nitrogen addition enhanced the uptake of N, P, S, K, Mn, Cu and Zn by plants, while inhibited plant Fe uptake, but with no effect on the uptake of Ca or Mg. Nitrogen addition increased aboveground net primary productivity (ANPP) but declined plant species diversity and community stability. Phosphorus addition alone increased total P and Olsen-P contents and fungal abundance in the surface soil, and improved N, P and S uptake by leaves, but had no significant influence on other soil basic chemical properties, ANPP, and plant species diversity. Water addition could improve the resistance of plant community, but its contribution to ANPP was limited by soil N availa-bility. Water addition could buffer soil acidification and the decline of microbial and plant diversity induced by N addition. Under the treatments of N and water addition or P and water addition, the diversity and function of soil microorganisms were affected by plant community structure and function. Long-term controlled field experiments were useful for understanding ecosystem structure and functions of grasslands. However, to uncover the underlying mechanisms in grassland ecosystem ecology, single-site experiments should be incorporated with multiple-site controlled field experiments in different regions. More attentions should be paid to the linkage of above- and below-ground ecological processes.

Carbon storage distribution characteristics of wetlands in China and its influencing factors.

LIU Ya-nan, XI Min, ZHANG Xi-li, YU Zheng-da, KONG Fan-long

2019, 30(7):  2481-2489.  doi:10.13287/j.1001-9332.201907.036

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Wetland plays an important role in stabilizing climate change and makes a significant contribution to global soil carbon storage due to its huge carbon storage capacity. Based on a summary of estimation methods of carbon storage, this study analyzed carbon storage and its influencing factors of typical wetlands in China, inclusing climate, vegetation, soil property and land use. The results showed that wetlands in Northeast China and the Tibetan Plateau had the highest carbon sto-rage among the eight wetland areas. Peat wetland had the highest carbon storage in inland area due to its higher stability, lower decomposition rate, and the impact of phenol oxidase. The bidirectional interference of single factor and combined effects of multiple factors made the influencing factors and mechanisms more complicated. Our results would contribute to the prediction and evaluation of wetland carbon storage and the value of ecosystem services through laying emphasis on the combined effects of multiple factors and applying the data assimilation technology.

Advances in biological wastewater treatment technology of microalgae.

PAN Yu, WANG Hua-sheng, LIU Zu-wen, YAN Hai

2019, 30(7):  2490-2500.  doi:10.13287/j.1001-9332.201907.038

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Microalgae has the advantages of high growth rates, high cellular lipid productivity and capability to bio-sequester carbon dioxide, and thus being widely studied as a new generation of biomass energy. The sustained investment in freshwater resources and nutrients during its growth period, however, is a major obstacle to large-scale cultivation. Combining a microalgae culture system with wastewater treatment is an economically viable wastewater resource utilization strategy. Based on the utilization mechanism of nutrients such as nitrogen and phosphorus during the growth of microalgae, we reviewed the application of microalgae in the biological wastewater treatment. The removal/inhibition ability of organic and inorganic compounds, heavy metals and pathogens were analyzed. The effects of environmental factors including the initial nutrient concentration, light, temperature, pH, salinity and gas exchange on the growth and metabolism of microalgae were investigated. In addition, combined with the problems faced by the large-scale application of microalgae, the application prospect and development direction of microalgae wastewater treatment were prospected, with the aim to provide references for the construction and management of water ecosystems.

Application potential of bryophyte soil crust on the control of karst rocky desertification

CHENG Cai, LI Yu-jie, LONG Ming-zhong, LI Xiao-na

2019, 30(7):  2501-2510.  doi:10.13287/j.1001-9332.201907.008

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Karst regions in southwest China are facing serious ecological problems, among which rocky desertification is the most serious one that is urgent to be controlled by more efficient and sustainable ways. We summarized the stress resistance of bryophyte, and the positive effects of bryophyte soil crust on soil stability, soil erosion resistance, soil organic matter content, soil nutrient status, water infiltration and evaporation, the redistribution pattern of precipitation in soil, the reproduction and survival of soil creatures, and the succession of vegetation and biodiversity in karst rocky desertification ecosystem. In those regions, bryophyte soil crust played irreplaceable roles in soil, hydrological and biological processes. The successful practices in desertification regions of north China indicated that artificially cultivated bryophyte soil crust had several advantages, including low cost and high compatibility with environment. In conclusion, artificial cultivation of bryophyte soil crust could be an important supplement to the current comprehensive control measures and will play an important role on the control of karst rocky desertification.

Regulating effect of agricultural landscape pattern on ecological pest control by natural enemies.

JIANG Ting, FU Dao-meng, ZHANG Wan-na, ZOU Yi, XIAO Hai-jun

2019, 30(7):  2511-2520.  doi:10.13287/j.1001-9332.201907.027

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It’s well known that regional agricultural landscape pattern can significantly regulate the relationship between plants, herbivorous insects and natural enemies. The improvement of the ecosystem services of regional agricultural landscape pattern has profound impacts on pest control, which has received much interests in current landscape ecology and pest control studies. This review systematically summarized the impacts of agricultural landscape pattern, as well as its succession on the diversity and ecological pests control of important natural enemies. From the perspective of different natural enemies, the impacts of agricultural landscape pattern on natural predators, parasi-toids, beneficial microorganisms and its ecological pests control functions were all recapped. We outlined crop spatial distribution and vegetation habitat management strategies. This review could provide useful insights in improving the ecosystem services of natural enemies in agricultural landscape based on the vegetation habitat management, and offer theoretical support for regional ecological agriculture in response to the strategy of ‘chemical pesticide reduction application’.