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Volume 38,Issue 13
  • Meta-ecosystem: Achievements in the first 15 years and the perspectives
  • Authors:YANG Haile and CHEN Jiakuan
  • Abstract:In 2003, Loreau, Mouquet, and Holt from France proposed the meta-ecosystem concept as a natural extension of the meta-population and meta-community concepts. A meta-ecosystem is defined as a set of ecosystems connected by spatial flows of energy, materials, and organisms across ecosystem boundaries. This concept provides a useful theoretical framework toward better understanding and exploring the structures, processes, functions, and heterogeneity of ecosystems. In this paper, we initially introduce the backgrounds of the meta-ecosystem concept, then, describe the development of meta-ecosystem studies, recapitulate the understandings of the meta-ecosystem concept in the current literature, summarize the frameworks for understanding the structure of meta-ecosystems, construct a six-dimensional general framework for describing a meta-ecosystem study, delineate two approaches to studying meta-ecosystems, and describe three spatial structures in empirical meta-ecosystems and two methods for constructing empirical meta-ecosystems. Finally, we explore the frameworks from a meta-ecosystem perspective, that might help future studies of integrated watershed ecosystems. We hope that 1) the review on meta-ecosystems could provide an overall framework for understanding the meta-ecosystem concept and meta-ecosystem studies, and then promote studies using the meta-ecosystem concept and theory; and 2) combining the meta-ecosystem theory and an integrated watershed ecosystem framework could provide a useful conceptual framework for watershed ecosystem studies and watershed ecology, and then support the sustainable development and ecological civilization at the watershed scale.
  • DownLoad:Meta-ecosystem: Achievements in the first 15 years and the perspectives.PDF
  • Survival status evaluation of giant panda based on elliptic catastrophe model
  • Authors:YAN Zhigang, LI Junqing and SUN Li
  • Abstract:Owing to strong protection measures, the threat to giant pandas was reduced from "endangered" to "vulnerable" by the IUCN in 2016. In recent years, national surveys of giant pandas revealed that the wild populations and habitat areas had increased constantly. However, habitat fragmentation and population isolation have become a more serious threat. Therefore, it is difficult to evaluate the current survival state of pandas accurately, although this is necessary for their protection. As a highly specialized animal utilizing the K-strategy, pandas are strongly dependent on their habitat ecosystems, and vulnerable to habitat fragmentation and population isolation. Therefore, the survival status of giant pandas should be evaluated from the perspective of the ecosystem. Based on the third and fourth national survey data, a multiple correlation analysis of population size with area of habitat and potential habitat was performed. We found a highly significant correlation between giant panda populations and habitats, implying that habitat conservation was the key to panda protection, and that there was a stable and close coupling relationship between wild populations and habitats. From the perspective of panda protection, this correlation constituted the basis for studying the ecosystem and designing ecosystem models. As a mature theory of systems science, the catastrophe theory provides a method of constructing system models with several key indices in the system, which can ignore the internal mechanism of the system. Considering the ecosystem of the distribution area of giant pandas as the research object, the number of wild pandas, and the area of the habitat and potential habitat as the key indices, the catastrophe theory was applied to this ecosystem. Moreover, the catastrophe potential function of the ecosystem was constructed, and the elliptic catastrophe model was derived. We found that, although the habitat area and number of wild populations continued to grow, the severe local population survival crisis and habitat fragmentation had generally weakened the systems' stability. The stability of the ecosystem is decreasing gradually and is very close to a critical state. Therefore, the ecosystem is still being subjected to great degradation pressures, and the survival crisis of giant pandas remains serious. Based on the current population and their habitat status, we suggested that all habitats needed to be protected effectively in the short-term. In addition, considering each large habitat as the center, corridors need to be constructed to connect the large population with surrounding small populations. In the long-term, more corridors need to be designed and constructed to expand the "star" network into a complex network, which will effectively withstand any disturbance. The catastrophe theory and its mathematical models were based on the entire system, and they included the relationships between the key elements, rather than solely on a few indices. This theory provided a coherent framework for modeling the complex dynamics of ecosystems. There are seven elementary catastrophes and corresponding models in the catastrophe theory, which have various potential applications. In addition to the evaluation of risk for biodiversity and the ecosystem, it has universal applicability in the study of ecology and as a methodology of system analysis.
  • DownLoad:Survival status evaluation of giant panda based on elliptic catastrophe model.PDF
  • Method for quantifying the contribution of urbanization on population exposure to air pollution
  • Authors:BIE Tong, HAN Lijian, TIAN Shufang, ZHOU Weiqi, LI Weifeng and QIAN Yuguo
  • Abstract:Rapid urbanization has negative effects on the ecological environment, especially the air pollution in some areas of China, where the air has been widely polluted by the major pollutant known as fine particulate matter (PM2.5) in recent decades. The population exposure in the contaminated area is generally due to the expansion of the contaminant's area, but is also highly attributed to the population migration caused by rapid urbanization. In this study, we established a quantitative model for evaluating the contribution of urbanization on the population exposed to air pollution, and selected the Beijing-Tianjin-Hebei urban agglomeration, which has been suffering the most severe PM2.5 pollution in China and undergoing rapid urbanization. By using PM2.5 concentration, population raster data, and population natural growth rate data from 2000 to 2015, we quantitatively explored the contribution of urbanization on the population exposed to air pollution. The results showed that:(1) the Beijing-Tianjin-Hebei area affected by pollution and population changed significantly, resulting in a large number of people exposed to PM2.5 pollution. (2) Contribution of population migration and natural growth caused by urbanization were varied:in general, the total population migration contribution rate, which is the percentage of migrated population in the total increased population that exposed to PM2.5 pollution, of the Beijing-Tianjin-Hebei urban agglomeration was 48%, the total population migration contribution rate of Beijing and Tianjin were 94% and 88% respectively, and that of Hebei Province was -32% from 2000 to 2015. In the continuously polluted area, the contribution rates of population migration in Beijing and Tianjin were close to 100% in 2000-2015, while the contribution rate of migration in Hebei was -26%; in Hengshui City, Hebei Province, the contribution rate of population migration was -6613% in 2010-2015. In the areas into which pollution expanded, the contribution of population migration in Beijing and Tianjin were 86% and 84% respectively, while the contribution rate of population migration in Hebei province was -757% in 2000-2015. This study establishes a quantitative approach to reveal the quantitative contribution of population exposure to air pollution caused by urbanization.
  • DownLoad:Method for quantifying the contribution of urbanization on population exposure to air pollution.PDF
  • Assessment of ecological vulnerability in the Yellow River Delta using the Fuzzy Analytic Hierarchy Process
  • Authors:WU Chunsheng, HUANG Chong, LIU Gaohuan and LIU Qingsheng
  • Abstract:The Yellow River Delta (YRD) is located in northeast Shandong province. It is formed by perennial deposition of sediment and frequent diversions of the Yellow River. YRD has many ecological system types, including farmland, grassland, and wetland and so on. The wetlands can be subdivided into meadows, marshes, and beaches. These areas have been the habitat and transfer stop of migratory birds, which makes it important for protection of biodiversity. It is also important as an ecological protective screen between inland and the ocean. However, YRD is facing new challenges from both nature and society; on the one hand, the storm tide, seawater intrusion, drought, and primary soil salinization make the area have a vulnerable ecologic foundation; on the other hand, the abundant land and oil resources have led to intense human activities. The primary ecological environment has been heavily fragmented because of destruction from farming and oil exploration, and the destruction further has led to a high secondary soil salinization degree and rapid expansion of the vulnerable area. All this makes it necessary to understand and grasp the current situation of the ecological environment in YRD, which is helpful for regional ecological environmental protection and development planning. The aim of this study was to evaluate the ecological vulnerability degree in YRD and then analyze the spatial characteristics and reasons for these characteristics according to the assessment results. The selected assessment method in the study was the fuzzy analytic hierarchy process (FAHP), which is the combination of the fuzzy evaluation method (FEM) and the traditional analytic hierarchy process (AHP). FAHP combines the strong objectivity of FEM and the clear structure of AHP. This assessment process was more reasonable than other methods. Additionally, the fuzzy logic model was selected for the quantitative expression of the indicator grading and evaluation results, and was different from traditional grading methods that have strict quantity boundaries. Twenty-one evaluation indicators were selected from underwater status, soil condition, land use, landform, vegetation coverage, meteorological conditions, ocean influence, and social economy according to the "pressure-state-response" framework in AHP. The study result showed that the spatial distribution of ecological vulnerability of YRD had a strong regularity. Generally, the vulnerability degree gradually decreased from the coastline to inland, and the best ecological environmental status was around the crossing of the Yellow River and the Diao River. In the coastal area, the vulnerability degree was lower where there were seawalls than where there were none, while in the inland, the ecological environment was better along the rivers than in other areas, especially the areas where human activity was frequent such as farmland, aquaculture areas, and saltpans, where the vulnerability degrees were very high. Along with those artificial reasons, the regional soil and ground status were also bound up with ecological vulnerability, and the spatial correlations between soil quality and ground water level were -0.55 and -0.74 respectively.
  • DownLoad:Assessment of ecological vulnerability in the Yellow River Delta using the Fuzzy Analytic Hierarchy Process.PDF
  • Driving effect measurements and spatial-temporal variation of the per capita gray water ecological footprint in China
  • Authors:ZHANG Zhixiong and SUN Caizhi
  • Abstract:In this study, the authors apply water ecological footprint measurement methods to the field of gray water footprint research and provide a method for calculating gray water ecological footprints. Based on the extended Kaya identity and the Logarithmic Mean Divisia Index (LMDI) technique decomposition methods, we calculated the gray water ecological footprint of 31 provinces and the per capita gray water ecological footprint in China from 2000 to 2014. We then measured and decomposed the values of the driving effects of per capita gray water ecological footprint change. From these results, we selected five of the more important economic and environmental factors to apply as capital factors to gray water research. This method included measurements of the effects of the working population, capital stocks, capital output coefficients, water ecological footprint intensity, and gray water ecological footprint emission coefficients. The five driving effects were economic activity, capital deepening, capital efficiency, footprint intensity, and environmental efficiency. The values of the driving effects on changes during the time period are discussed and analyzed based on the Iterative Self-Organizing Data Analysis Techniques Algorithm (ISODATA) clustering model for spatial clustering of the effects. The results showed that the Chinese per capita gray water ecological footprint output changed because of the interaction of these five factors. Among them, the incremental capital deepening effect was obvious, as a large amount of capital has been invested to promote rapid development of the regional economy and to employ a rapidly growing population. Economic activity can also promote the characteristics and the size of regional economies as population growth will increase regional demands for water. The other capital deepening effect is a decline in the output efficiency of capital. With the rapid development of its economy, China is in a period of industrialization and urbanization. The economic structure has gradually changed from a population-intensive to a capital-intensive structure. Industry, especially heavy industry, had a higher initial investment and a lower output efficiency, which is why the effect of capital efficiency continues to decrease. The most obvious effect on footprint intensity was the effect of per capita gray water ecological footprint reduction. With the improvement of economic activity and advances in science and technology, the water ecological footprint intensity has been greatly reduced. As a result of the effective control of pollutant emissions, the per capita gray water ecological footprint in most provinces and cities has shown a decreasing trend. A reduction in environmental efficiency is an inevitable consequence of a decrease in the water ecological footprint intensity. With a decrease in water ecological footprint intensity, more water is reused and we can improve water efficiency in most provinces to reduce the gray water ecological footprint. This study discusses the relationship between gray water ecological changes and capital factors; the reported results have value as a reference for the adjustment of environmental policies and the sustainable utilization of water resources.
  • DownLoad:Driving effect measurements and spatial-temporal variation of the per capita gray water ecological footprint in China.PDF
  • Study on spatial-temporal change andtrade-off/synergy relationships of ecosystem services in the Danjiangkou water source area
  • Authors:LIU Hai, WU Jing and CHEN Xiaoling
  • Abstract:Ecosystem management that attempts to maximize the production of one ecosystem service may result in substantial declines in the provision of other ecosystem services. For this reason, understanding the trade-offs and synergies of ecosystem services is of considerable significance to balance the characteristics of multiple ecosystem services and maximize the benefits of ecosystem services. The current situation is that there is insufficient researches on qualitative analysis and long time series of dynamic change among the trade-offs and synergies relationship. In addition, the selection of ecosystem services are inadequate. The Danjiangkou water source area is an important area of the South-to-North Water Diversion Project, and clarifying the temporal and spatial variation characteristics and relationships among ecosystem services can provide reference guidance for the smooth progress of the water transfer project in the middle route of the South to North Water Transfer project. At present, analysis of the relationships among ecosystem services in the Danjiangkou water source area is still insufficient. Given this situation, we studied the ecosystem service relationships of a long time series in the Danjiangkou water source area using different methods. First, we used the equivalent factor method to estimate the ecosystem service value. We then discuss the spatial-temporal difference and relationship of ecosystem services in six periods by correlation analysis and using an ecosystem services trade-off degree (ESTD) model. Correlation analysis has the advantage over long time series analysis. The ESTD model has the advantage of dynamic change analysis for short time periods. The results showed that during the period of 1990 to 1995, the value of ecosystem services in the Danjiangkou water source area showed a negative growth. However, the value of ecosystem services significantly improved from 1995 to 2015. The largest increase in ecosystem services occurred in water supply, and forest land provided the highest value of ecosystem services. Ecosystem service value increased from northeast to southwest. Correlation analysis showed that synergy is the dominate relationship among ecosystem services, and that there are few trade-offs in the Danjiangkou water source area. Since the Danjiangkou dam was heightened (after 2005), the relationship among ecosystem services in the water source area have changed. The trade-off relationships in the water source area increased among water supply, hydrological adjusting, and environment depuration, and trade-offs were reduced in other ecosystem services. Human disturbance is the most important factor that results in ecosystem service change.
  • DownLoad:Study on spatial-temporal change andtrade-off/synergy relationships of ecosystem services in the Danjiangkou water source area.PDF
  • Response of agricultural land carbon storage to land use change in Beijing from 1980 to 2010
  • Authors:HU Yingjie, LI Yue, KONG Xiangbin, DUAN Zengqiang and LU Minghuan
  • Abstract:As the capital of China, Beijing has experienced rapid urbanization and industrialization during the past three decades. The analysis of variation of its carbon storage in agricultural land and response characteristics to land use change are of great significance for regional and national regulation of low carbon utilization in agricultural land. Using the second soil census data in 1980 and the results of soil testing and fertilization in 2010, the topsoil carbon storage of agricultural land were calculated and the vegetation carbon storage of forest and grassland were obtained from biomass inversion based on remote sensing. The response characteristics of carbon storage in agricultural land to land use change in Beijing from 1980 to 2010 were analyzed by combining the soil and vegetation carbon storage and land use change information. The major results were as follows:1) the carbon storage in agricultural land of Beijing increased from 75.29 Tg-C in 1980 to 81.13 Tg-C in 2010 by 5.83 Tg-C, the soil organic carbon (SOC) storage of in agricultural land in Beijing decreased by 7.51 Tg-C, whereas the vegetation carbon (VC) storage increased by 13.34 Tg-C; 2) the in agricultural land area in Beijing decreased by 14.11×104 hm2 during the past three decades and cropland decreased by 14.62×104 hm2. Most of the lost cropland was converted into construction and forest land. The forest land area increased slightly by 1.13×104 hm2, whereas the grassland area decreased by 6.29×104 hm2; 3) the SOC storage of the maintained land use types of in agricultural land in Beijing decreased by 297.63×104 t, and the loss was overcompensated by increased VC storage of 1095.21×104 t. The carbon storage of maintained land use types of in agricultural land increased by 97.58×104 t. The carbon storage of maintained cropland and forest land increased, whereas the carbon storage of maintained grassland decreased; 4) the land use type conversion resulted in a decrease of in agricultural land SOC storage in Beijing by 75.71×104 t and increase in VC storage by 212.49×104 t. The carbon storage increased by 136.78×104 t through land use type conversion of in agricultural land in Beijing. The conversion of other land use types to forest land resulted in an increase in the carbon storage and the opposite conversions were not conducive to carbon absorption; 5) the implementation of plain afforestation, returning farmland to forests, and other projects would be beneficial to the carbon sequestration of in agricultural land in Beijing. In the future, we could improve the carbon fixation capacity of in agricultural land in Beijing by controlling the reduction of farmland area, optimizing the internal in agricultural land structure, and reducing the frequency of conversion between land use types. The results of this study could provide a reference for other regions and countries to improve the carbon storage of in agricultural land during rapid urbanization and industrialization.
  • DownLoad:Response of agricultural land carbon storage to land use change in Beijing from 1980 to 2010.PDF
  • Quantitative assessment of water conservation function and spatial pattern in Shiyang River basin
  • Authors:WANG Yuchun, ZHAO Jun, FU Jiewen and WEI Wei
  • Abstract:Water conservation function is one of the most important ecosystem service functions of river basin ecosystems, and it is also the key factor for sustainable development.We used the InVEST model to quantitatively evaluate the water yield and conservation function of the Shiyang River Basin using parameter localization, and graded the importance of water conservation function. Furthermore, we analyzed the differences in the water yield and water conservation function by simulating different farmland conversion scenarios. We obtained the following results:(1)When the Zhang value was 2.1 in the InVEST model, the simulation results of the water yield in the study area were the best. The average water production depth in the study area was 60.90 mm, and the total water yield was 24.71×108 m3.The average water conservation of the unit was 23.97 mm, and the total water conservation was 1.35×108 m3 in 2015. The unit water depth and average spatial distribution of the water conservation unit showed a north-south high-low trend. The unit and total water conservation capacities were the highest for the forest and the grassland,respectively.(2)The water conservation function of the generally important area which refers to poor water conservation function had a proportion of 53.49%,whereas the very important region accounted for 22.40% of the total area.(3)The scenario simulation results of the different returning farmland models revealed that when the forest area was the largest, the water conservation capacity and the total water conservation amount were the highest. Furthermore, increasing the forest land and grassland area decreased the water yield, and when the forest area was the largest, the water yield was the lowest. Based on the minimum ambiguity method, a model of returning farmland to forest and grassland was developed.
  • DownLoad:Quantitative assessment of water conservation function and spatial pattern in Shiyang River basin.PDF
  • Structural equation modeling analysis of theresponse of herbaceous species richness to landscape factors in a forest-steppe zone
  • Authors:TIAN Xiaomin, ZHENG Jianwei, WANG Dongzhi, HUANG Xuanrui and ZHANG Zhidong
  • Abstract:Fragmented landscapes are mosaics of vegetation patches with differing proportions. A more comprehensive understanding of the effect of landscape structure characteristics on species diversity is necessary to improve conservation strategies for species diversity in fragmented landscapes. Sampling plots were established in 38 natural vegetation patches within the Saihanba Nature Reserve, including 12 herbs, 11 shrubs, and 15 natural forest vegetation fragments. Herbaceous plant species were divided into C3 and C4 functional groups according to their photosynthetic carbon-assimilating pathway. The patch area, shape index, isolation index, and percentage of forest and grassland within a 500 m radius from the boundary of each sampling patch were selected as the landscape factors. A structural equation model (SEM) was adopted to explore the relationships between species richness of functional groups (C3 and C4) and landscape factors. Patch area (2.18-74.06 hm2) had a significant positive effect on C3, C4 herbs, and total species richness (P < 0.05), and the effect on C3 herbs was the highest; the shape (1.06-3.11) and isolation (33.51-327.65) indexes had no significant effect on C3, C4 herbs and total species richness (P > 0.05); the species richness of C3, C4 and all herbs increased with increasing grassland proportions (4.20%-64.95%) in the surrounding matrix, whereas the percentage of forest (35.05%-95.80%) in the surrounding matrix did not have a direct effect. Patch area and vegetation composition of adjacent patches were the main factors affecting the C3 and C4 herbs in Saihanba Nature Reserve. Preserving the large natural vegetation patch and improving the proportion of grassland in the surrounding matrix could effectively conserve key C3 and C4 herbaceous plant species.
  • DownLoad:Structural equation modeling analysis of theresponse of herbaceous species richness to landscape factors in a forest-steppe zone.PDF
  • Dynamic changes in soil seed banks and their relationships with aboveground vegetation during the decaying of Haloxylon ammodendron plantations at the edge of the Minqin oasis
  • Authors:HE Fanglan, GUO Chunxiu, MA Junmei, WU Hao and JIN Hongxi
  • Abstract:The Minqin oasis is located in the northwest Hexi Corridor, and the northern, western, and eastern edges are surrounded by the Tengger and Badain Jaran deserts. To manage sand and prevent sandstorms, large tracts of Haloxylon ammodendron plantations were previously planted on the fixed and semi-fixed sand dunes of the Minqin oasis fringe. At present, parts of the H. ammodendron plantations, especially those close to the oasis, have presented with a degradation phenomenon due to multiple affecting factors. To ascertain the changes in soil seed banks and their relationships with aboveground vegetation during the degradation process of H. ammodendron plantations, some tracts of H. ammodendron plantations planted in 1987 were divided into no degradation (ND), slight degradation (SLD), moderate degradation (MD), and serious degradation (SD) stages, according to the growth status of these plants and their seedlings, as well as the coverage of biological soil crust. In the present study, the species composition, density, and species diversity of soil seed banks and their relationships with aboveground vegetation were studied, with field monitoring and indoor germination methods. The results showed that 1) with an increased degree of degradation of H. ammodendron plantations, the number of woody plants in the soil seed banks first decreased rapidly and then remained stable, and the number of herb plants in the soil seed banks, first increased rapidly and then decreased slowly, so that the peak emerged at the SLD stage. At the same time, dominant species in soil seed banks presented a succession trend from typical psammophytes to xerophytes, and the species similarity coefficients of soil seed banks and aboveground vegetation, as calculated by Jaccard's similarity coefficient, appeared to increase from ND to SLD and then decrease from SLD to SD. 2) The soil seed bank density of herb plants rapidly increased their stage of degradation from ND to SLD and slowly decreased from SLD to SD, while the soil seed bank density of woody plants has been increasing continuously and dramatically. The densities of herb plants and woody plants in the SLD, MD, and SD stages were 2.57 and 5.25, 2.32 and 11.38, and 2.28 and 14.74 times higher than that of ND, respectively. There was a positive correlation between the species in soil seed banks and aboveground vegetation, such that this relationship for herb plants can be described with a logarithmic curve of y=aln (x) + b (a ≠ 0), and for woody plants may be described with a quadratic curve of y=ax2 + bx + c (a ≠ 0). 3) With the evolution from the SLD stage in H. ammodendron plantations to the SD stage, some species diversity indices, such as Dma, Dsim, H', and Jsw, of herb plants in soil seed banks were initially obviously stable and then showed significant change, while the indices of woody plants showed continuous change. In addition, some obvious differences have been presented between trends of these indices in soil seed banks and in aboveground plants, while the degrees of change in soil seed banks were similar to those of aboveground plants. The changes in trend in the indices of woody species in soil seed banks were completely consistent with those in the indices of aboveground plants; however, the degrees of change in soil seed banks were smaller than those in the aboveground plants. These findings suggest that the degradation of H. ammodendron plantations is a succession from psammophytes to xerophytes, there is a strong interdependence between soil seed banks and aboveground vegetation, and soil seed banks in the degrading plantations will have a stronger potential for vegetation recovery due to the increase in seed bank stocks of some species, which is a response to increase the stability of the plant communities.
  • DownLoad:Dynamic changes in soil seed banks and their relationships with aboveground vegetation during the decaying of Haloxylon ammodendron plantations at the edge of the Minqin oasis.PDF
  • Response of the relationship between radial growth and climatic factors to abrupt change of temperature along an altitudinal gradient on the northern slope of Changbai Mountain, Northeast China
  • Authors:ZHOU Zijian, JIANG Yuan, DONG Manyu, TAO Yan, WANG Mingchang and DING Xinyuan
  • Abstract:The radial growth of trees is affected by complex environment. To predict the radial growth dynamics of Pinus koraiensis in the context of climate change, tree ring cores of P. koraiensis were collected from sampling sites at different elevations (745 m a.s.l., 1134 m a.s.l., and 1280 m a.s.l.) on the northern slope of Changbai Mountain. Using a dendrochronological method, we investigated the variability in the responses of radial growth to climatic factors and the temporal stability of the responses at different elevations. The results from the Mann-Kendall test showed that an abrupt change in annual mean temperature occurred in 1987. Tree growth at the low elevation was mainly influenced by the precipitation that occurred in June and July, whereas tree growth at the middle and high elevations was mainly affected by the mean minimum temperature of July. After the abrupt change in temperature, the growth-climate relationship was relatively stable at the low elevation; however, the response of radial growth to precipitation during November of the previous year at the middle elevation and to precipitation that occurred in May at the high elevation changed significantly. Therefore, in the context of an abrupt change in temperature, the chronology of P. koraiensis at low elevations is more suitable for the study of regional climate reconstruction. However, when the temperature continued to rise, the radial growth of P. koraiensis showed a downward trend at the low elevation, whereas at the middle and high elevations, tree growth first increased and then decreased.
  • DownLoad:Response of the relationship between radial growth and climatic factors to abrupt change of temperature along an altitudinal gradient on the northern slope of Changbai Mountain, Northeast China.PDF
  • Spatial heterogeneity of biodiversity value based on dominant species: Changbaishan Ecological Function Zone as a case study
  • Authors:LIN Chen, GONG Minghao, LIU Yang, PAN Xu and PIAO Zhengji
  • Abstract:Understanding spatial heterogeneity, which is a dominant function in ecosystem biodiversity, can help to highlight the conservation value and importance of a given area. However, there are limited available methods to assess the spatial heterogeneity of biodiversity value. We chose the kernel area of the Changbaishan Ecological Function Zone as the study site and constructed an assessment model of biodiversity value based on the dominant species in an area with high species richness and environmental variables, by using Maxent. Based on the aggregation of the dominant species and results of the biodiversity assessment, we partitioned the study area as into three areas of high, medium, and normal biodiversity values. Our study showed that the area with a high biodiversity value occupied 42.9% of the total study area and was mainly located within the Changbaishan Reserve; and the areas with high and normal biodiversity values comprised the main range of the Changbaishan Reserve. The mean and largest patch sizes of high biodiversity value were much larger than those of the medium and normal biodiversity values, reflecting the integrity and low fragmentation level in the landscape pattern, suggesting the competent function and robust stability of ecosystem and biodiversity values in our study. Together, the patches of high biodiversity value in the reserve were also larger and more integrated than those outside the reserve, and the order of the mean size with sub-function areas of the reserve was as follows:kernel area > buffer area > experimental area. Among the environmental factors, vegetation was the most important for the biodiversity value, followed by the soil depth and elevation in the study area. Based on the needs of protecting the ecosystem integrity and eco-process connectivity, the south buffer zone of the reserve should be incorporated into kernel areas; the large area with high and medium biodiversity values should be managed for more efficient conservation; and western Changbaishan Mountain was the most fragmented area with high diversity values and should be the focus of future conservation and management efforts. Our study also indicated that this method was effective to examine the spatial heterogeneity of biodiversity by associating the presence of dominant species with environmental variables and could be applied to biodiversity studies in other ecological function areas to delineate ecological conservation redlines and effectively design national parks.
  • DownLoad:Spatial heterogeneity of biodiversity value based on dominant species: Changbaishan Ecological Function Zone as a case study.PDF
  • Differences in community characteristics, species diversity, and their coupling associations among three forest types in the Huzhong area, Daxinganling mountains
  • Authors:ZHANG Jianyu, WANG Wenjie, DU Hongju, ZHONG Zhaoliang, XIAO Lu, ZHOU Wei, ZHANG Bo and WANG Hongyuan
  • Abstract:Exploring the differences and coupling relationships of species diversity and stand characteristics could provide data with which to improve biodiversity and ecological services of natural forests. In this study, three typical communities of larch forest, shaw (mixed forest with various tree species), and birch-larch forest were selected at Huzhong in the Daxinganling mountains for measuring stand characteristics (height, diameter at breast height[DBH], crown width, coverage, and others), richness index, diversity indexes, and evenness indexes of the arbor layer, shrub layer, and herb layer. Canonical correspondence analysis (CCA) was used to uncover their differing associations among forest types, together with a multiple analysis of variance to detect the inter-forest differences. The results showed that (1) the height and clear tree bole height of the arbor layer differed with shaw > larch forest > birch-larch forest (P < 0.05); DBH of the larch forest was 6% and 11% higher than that in the birch-larch forest and the shaw, respectively. There were no significant differences in the shrub layer in the parameters of height, canopy coverage, ground diameter, crown width, as well as in the herb layer for species abundance, herb coverage, and herb height. (2) The maximum species richness, Shannon-Wiener index, and Simpson index of the arbor layer, shrub layer, and herb layer all occurred in the shaw relative to the larch forest and the birch-larch forest. Moreover, the herb layer showed the same pattern as in the arbor layer, i.e., shaw > birch-larch forest > larch forest; however, the shrub layer exhibited a different order, with shaw > larch forest > birch-larch forest. The species evenness of the arbor layer in the birch-larch forest and shaw were approximately three times that of the larch forest; however, there was no significant difference in the shrub layer and the herb layer (P > 0.05). (3) CCA showed that the correspondence associations between community characteristics and species diversity differed among the three forest types. In general, for all three forests the characteristics of the shrub (ground diameter and crown width) and herb layer (coverage, abundance, and height) had a substantial influence on plant species diversity. Plant diversity was significantly affected by tree DBH in the birch-larch forest and the shaw; however, it was highly significantly affected by tree height in the larch forest. With the increase of shrub coverage and herb height, herb diversity decreased; whereas decreasing herb diversity usually corresponded with increasing diversity of the arbor and shrub layer in the shaw. In the larch forest, herb height increase, together with decreases in abundance and coverage usually corresponded with a decrease in herb diversity, and increases in arbor and shrub diversity. An increase in shrub diversity was usually accompanied by a decrease in arbor and herb diversity, but corresponded with increases in tree DBH, herb abundance, and coverage, and decreases in shrub crown width in the shaw; however, it was accompanied by decreases in shrub crown width, as well as herb abundance and coverage in the birch-larch forest. Our findings highlighted that community characteristics were closely coupled with species diversity, and the above-mentioned decoupling results will favor diversity conservation through maintaining good forest structure in the Daxinganling Mountain Region, Northeast China.
  • DownLoad:Differences in community characteristics, species diversity, and their coupling associations among three forest types in the Huzhong area, Daxinganling mountains.PDF
  • Adaptability of drought situation monitor in Xinjiang with the NDVI-LST index
  • Authors:PENG Qing, WANG Ranghui, JIANG Yelin and WU Xiaoquan
  • Abstract:In this study, the spatial-temporal characteristics of vegetation status, drought conditions, and their correlation were studied through three phases of the normalized difference vegetation index (NDVI), land surface temperature(LST)-moderate resolution imaging spectroradiometer (MODIS) database during the growing season in Xinjiang from 2000 to 2015. In addition, a multivariate linear regression method was used in this study to analyze the meteorological factors that could influence the relationship between NDVI and LST of different phases. The spatial-temporal characteristics of the relationship between NDVI and LST were analyzed by dividing different land use cover changes (LUCC). The results showed that (1) there was a significant correlation between LST and NDVI in the third quarter of the growth season, and drought conditions could be evaluated using the relationship between NDVI and LST. (2) The influence of meteorological factors on the NDVI-LST correlation was different in various phases in Xinjiang. Moreover, there were significant differences in NDVI-LST correlations among different LUCC. (3) It was effective to monitor vegetation health and drought conditions in most areas of Xinjiang using a vegetation health index in the middle of the growing season, whereas earlier and latter drought assessments needed to be supplemented by other drought indices.
  • DownLoad:Adaptability of drought situation monitor in Xinjiang with the NDVI-LST index.PDF
  • Species diversity and stability of grassland plant community in heavily-degraded karst tiankeng: a case study of Zhanyi tiankeng in Yunnan, China
  • Authors:JIAN Xiaomei, SHUI Wei, WANG Ya'nan, WANG Qianfeng, CHEN Yiping, JIANG Cong and XIANG Ziyuan
  • Abstract:Karst tiankeng, named in the early 21st century, is a grand negative landform, and its intrazonal habitat conditions are suitable for animal and plant growth and reproduction. In recent years, with the deep excavation of the scientific and aesthetic value of tiankengs, unique habitat characteristics and plant communities of original and mature tiankeng are valued gradually, but the research of degraded tiankeng is still relatively weak. Dazhujing belongs to the typically, heavily-degraded tiankeng in Yunnan, which has higher accessibility and a grassland community in the bottom section of the tiankengs. Therefore, choosing the study area-Dazhujing to analyze the plant communities on the inner and outer parts of tiankeng, it can improve existing theoretical knowledge system and provide significant reference for the ecological restoration of the karst area. This method of field sampling and statistical analysis had been employed to study the characteristics and degree of stability of karst tiankeng's plant community from a qualitative and quantitative point of view. The results showed that:1) There were 35 species belonging to 14 families and 35 genera inside the tiankeng, and 30 species belonging to 14 families and 30 genera outside the tiankeng. The species composition was relatively diverse, with only one co-dominant species; 2) Degraded tiankeng had fragile habitats, and plant diversity outside the tiankeng was higher than that inside the tiankeng, however, the difference was non-significant. In contrast, species evenness outside the tiankeng was significantly higher than that inside the tiankeng; 3) The two communities inside and outside the tiankeng were at very dissimilar levels, which had different and diverse structures and significantly different habitats; 4) The plant communities inside the tiankeng had a non-significant positive inter-specific association, were loose, independent, and at the positive succession stage. However, a negative correlation was found between the plant communities outside the tiankeng, which were at an unstable stage; 5) The stability analysis showed that there was still a gap in community stability, which indicated that the ecosystem of the degraded tiankeng was still fragile.
  • DownLoad:Species diversity and stability of grassland plant community in heavily-degraded karst tiankeng: a case study of Zhanyi tiankeng in Yunnan, China.PDF
  • Effects of simulated sulfate deposition on methane flux from a Sagittaria trifolia-dominated freshwater tidal wetland in the Min River estuary
  • Authors:ZHANG Yifei, LIU Xiaohui, YANG Ping, HUANG Jiafang, GUO Qianqian and TONG Chuan
  • Abstract:Exogenous sulfate (SO42-) resulting from human activity, can strongly influence the emission of methane (CH4) from wetland ecosystems. Previous studies have reported the suppression CH4 emissions of peatlands and paddies by cumulative SO42- deposition in simulated acid rain conditions. However, very few studies have presented data on the effect of the addition of SO42- on CH4 emissions in estuarine freshwater tidal wetlands. In this study, the effect of simulated deposition of SO42- on the CH4 emissions was examined by manipulating SO42- inputs to a Sagittaria trifolia-dominated freshwater tidal wetland in the Tajiaozhou area of the Min River estuary from December 2015 to October 2016. Monthly pulses of dissolved K2SO4 were applied over one year at doses of 60 and 120 kg S hm-2 a-1 (abbreviated as S-60 and S-120, respectively), and CH4 fluxes were measured at regular intervals using a static chamber/gas chromatographic method. On the annual scale, the average CH4 emissions from the control, S-60-and S-120-amended plots were 7.88±1.00, 6.55±0.97 and 6.66±1.49 mg h-1 m-2, respectively. Thus, the two addition treatments did not significantly decrease the CH4 emissions from S. trifolia-dominated freshwater tidal wetland, which is different from the effects of simulated SO42- deposition on the CH4 emissions from peatlands and paddies in other reports. The S-60 and S-120 treatments significantly increased the pore water SO42- concentrations at a depth of 10 cm in the S. trifolia wetland at an annual scale as well as in autumn and winter. CH4 emissions in summer and autumn were significantly higher than those in winter and spring. CH4 emissions from the control, S-60-and S-120-amended plots demonstrated significant positive correlations with soil temperature. These results indicate that soil temperature is an important environmental factor affecting the temporal variation of CH4 emission from a subtropical estuarine freshwater tidal wetland.
  • DownLoad:Effects of simulated sulfate deposition on methane flux from a Sagittaria trifolia-dominated freshwater tidal wetland in the Min River estuary.PDF
  • Effects of environmental factors on seed germination and seedling establishment of Caryopteris mongolica
  • Authors:HE Yiming, LI Qingfeng, HE Xiao, FAN Ruyue, DUAN Ruhui and LIU Yang
  • Abstract:Caryopteris mongolica, a rare and endangered small shrub, is mainly found in arid grasslands in northern China. Its distribution areas have rapidly contracted in recent years. In this study, an attempt was made to investigate the causes of the low survival rate of seedlings under local field conditions. The study combined a field survey of seedling survival with laboratory assessments of seed germination and seedling growth under different environmental conditions to establish the difficulties for C. mongolica seedling establishment. We selected a C. mongolica community in arid grasslands. The survival capacity of seedlings, seed germination, and seedling establishment under different temperatures, water cycles, and water quantities were determined. Climate and soil conditions were also studied. The following results were obtained. (1) Under field conditions, a large number of seeds germinated during the period from May to July, but few seedlings survived due to a high seedling mortality. The natural regeneration rate for the plant seedlings was 0.11 plant/m2, because of the very high mortality rate of seedlings. (2) Seeds of C. mongolica had no dormancy after ripening. Seed germination requirements showed a relatively wide range of moisture conditions, but a narrow temperature range of 25-30℃. The optimum burial depth for seed germination was 10-15 mm. The seeds of C. mongolica can complete germination within 15 days when sown under suitable conditions. The water cycle had no significant effect on germination. The seeds buried in shallow soil were able to imbibe rapidly after full precipitation. (3) The most suitable temperature for seedling growth was approximately 25℃, although seedlings could tolerate a high temperature of up to 50℃ for a short period. Prolonged high or low temperature and frequent watering increased seedling death. The water cycle significantly influenced plant height and stem basal diameter. Shortening the water cycle can increase the height and stem thickness of C. mongolica. There was a significant influence of temperature on leaf age. The optimum temperature for leaf growth of C. mongolica was 25℃. Furthermore, variable temperature conditions were beneficial for erect growth and the thickening of stems. It was concluded that C. mongolica has relatively strict requirements for seed germination and seedling growth. The discrepancy between germination and seedling growth requirements narrowed the seedling establishment window. In the natural habitats of C. mongolica, the conditions are often not able to meet the requirements for the entire process from seed germination to seedling establishment. This is the main reasons for the relatively poor dispersion of C. mongolica populations through sexual propagation under field conditions.
  • DownLoad:Effects of environmental factors on seed germination and seedling establishment of Caryopteris mongolica.PDF
  • Relationship between plant species, life form, functional group diversity, and biomass under grazing disturbance for four years on an alpine meadow
  • Authors:NIU Yujie, YANG Siwei, WANG Guizhen, LIU Li, DU Guozhen and HUA Limin
  • Abstract:This study was performed to gain an understanding of the time cumulative effects of grazing intensity on the diversity of species, life forms, functional groups, and biomass and their relationships on an alpine meadow. From 2012 to 2015, we conducted a controlled grazing trial with six grazing intensities on an alpine meadow located in the northeastern Qinghai-Tibet Plateau. We investigated the diversity and life form of species, functional group diversity (richness, evenness, and dominance were used as diversity indices), and aboveground biomass in four years. We used repeated measures and linear regression methods to analyze the effect of grazing intensities and grazing years on plant species diversity, life forms, and functional groups, as well as on the relationship between the diversities and biomass. The following results were obtained. (1) Grazing intensity and grazing year had significant effects on biomass, with the biomass significantly decreasing with an increase in grazing intensity. There was irregularity in biomass changes in different grazing intensity plots with progression of the grazing year. (2) There were significant effects of grazing year on abundance, evenness, and dominance in term of the plant species, life forms, and functional groups. However, the grazing intensity and grazing year had an interactive influence on the richness of plant species, and grazing intensity had a time cumulative effect on the richness of plant species. (3) In the plant diversities with different organizational levels under grazing disturbance, only the richness of plant species was significantly correlated with all diversity indices. The richness of plant species can be used as a representative index for measuring plant species diversity. (4) In the study of the relationship between diversity and biomass, the richness of plant species in the lighter grazing intensity plot (Plot 2) was significantly decreased with increasing biomass, whereas the richness of plant species, life forms, and functional groups showed no relationship with biomass in other grazing intensity plots. The evenness of life forms in the high intensity grazing plots (Plots 4, 5, and 6) significantly decreased with an increase in biomass. The dominance of life forms in the high intensity grazing plots (Plots 4, 5, and 6) significantly increased with an increase in biomass. In conclusion, the diversity of life forms can be used as an effective index for rapidly predicting plant biomass under grazing disturbance because this diversity is the most sensitive to biomass variation.
  • DownLoad:Relationship between plant species, life form, functional group diversity, and biomass under grazing disturbance for four years on an alpine meadow.PDF
  • Characteristics of sap flow dynamics in dominant and companion trees in a natural secondary oak forest in the loess hilly region
  • Authors:LIU Xiaoxiao, HE Qiuyue, YAN Meijie, LI Guoqing, WANG Shiwen and DU Sheng
  • Abstract:Granier-type thermal dissipation probes were applied to continuously measure the stem sap flow dynamics in oak (Quercus liaotungensis) and three other tree species (Armeniaca sibirica, Acer stenolobum, and Euonymus bungeanus) representing the dominant and companion species, respectively, during the growing season from May to October, 2011, in a natural secondary forest near Yan'an of Shaanxi Province in the loess hilly region. Solar radiation (Rs), air temperature, and relative air humidity were monitored simultaneously. The diurnal dynamics of sap flux densities and their responses to environmental factors for the four tree species (Q. liaotungensis, A. sibirica, A. stenolobum, and E. bungeanus) were analyzed. The results showed that patterns of diurnal variation of sap flux densities in the four species were similar, with a single-or double-peak curve, generally reflecting the changes in environmental factors (e.g., Rs). However, there were some differences among the four tree species. The starting time of sap flow in Q. liaotungensis was usually around 05:00, more than 1 hour earlier than the other three species. Sap flux densities in Q. liaotungensis reached daily peaks earlier than others, usually around 09:00, whereas A. stenolobum, E. bungeanus, and A. sibirica reached their daily peaks at 10:00, 11:00, and 13:00, respectively. The companion species A. stenolobum and E. bungeanus showed a relatively narrow peak in their diurnal patterns of sap flux densities, suggesting a limitation of radiation conditions within the community. In addition, soil moisture conditions showed a more obvious effect on companion tree species than on the dominant species. Correlation analysis indicated that sap flux densities were significantly correlated with both solar radiation and vapor pressure deficit during the monitoring period. The difference in sap flux densities between dominant and companion trees may be attributed to both properties of the tree species and redistribution of radiation by canopies.
  • DownLoad:Characteristics of sap flow dynamics in dominant and companion trees in a natural secondary oak forest in the loess hilly region.PDF
  • Nitrogen and phosphorus concentration, and storage dynamics of Carex cinerascens during the spring growing season in Poyang Lake wetland
  • Authors:BAI Xiuling, ZHOU Yunkai, WANG Jiehua and LI Wenli
  • Abstract:Wetland plants play an important role in the biogeochemical cycling of nutrients. Studying the absorption, distribution, and accumulation of nitrogen (N) and phosphorus (P) in plants is of great significance in understanding the key processes of nutrient cycling and their ecological functions. Therefore, field observations and laboratory measurements were used to study the dynamic changes in biomass as well as the N and P contents and their storages in Carex cinerascens in the spring growing season in Poyang Lake wetland. The results showed that there was a time-dependent increase in the biomasses of different components of C. cinerascens during the spring growing season whereas the aboveground biomass was higher than that of the belowground in each growing period. Furthermore, the accumulation rate of the belowground biomass was relatively constant whereas that of the aboveground and total biomasses was higher in the early growing stage than it was in the late growing stage. The N and P contents in the different parts of C. cinerascens decreased from March to April and then increased from April to May. The N content of the aboveground part was higher than that of the belowground part in each growing period, and the difference was significant in April and May (P < 0.01). The P content had similar distribution characteristics to those of the N content, but the difference was more significant in March and April (P < 0.01) than it was in other months. The N and P storages in C. cinerascens showed a significantly positive correlation with the biomass (P < 0.01), and their dynamics were determined based on the biomass variation of C. cinerascens. Further, the aboveground part of C. cinerascens contained the main N and P pools. The N/P ratio is an important ecological indicator that can be used to detect the nutrient limitation. Based on the theory of nutrient limitation, N may be a key nutrient factor that limits the primary productivity of C. cinerascens.
  • DownLoad:Nitrogen and phosphorus concentration, and storage dynamics of Carex cinerascens during the spring growing season in Poyang Lake wetland.PDF
  • Study on evaporation variation of jujube trees under drip irrigation of jujube and cotton intercropping in an arid area
  • Authors:AI Pengrui, MA Yingjie and MA Liang
  • Abstract:This study was conducted in order to clarify the characteristics of soil evaporation and water dissipation in jujube trees and intercropping trees. On the basis of field experiments, we examined the changes in soil evaporation, meteorological factors, soil factors, and boundary effect by means of micro-lysimeter monitoring of the soil evaporation of jujube trees and intercropping. The following results were obtained. Soil evaporation differed at the different growth stages of jujube trees. There were significant differences in soil evaporation and transpiration between single and intercropping trees, and it was generally higher in monoculture than with intercropping. Investigation of external influencing factors indicated that the soil evaporation of jujube trees showed a good functional relationship with solar radiation and soil water content. Although the daily average temperature was related to the soil evaporation of single cropping trees, the correlation with intercropping was poor. When the boundary effect of intercropping jujube tree was analyzed, it was found that intercropping cotton significantly affected soil evaporation between intercropped jujube trees, and the leaf area index of cotton showed a good 2-fold relationship with soil evaporation. To some extent, this study reveals the advantages of the intercropping model, which provides a theoretical basis for reducing inefficient water consumption and improving water-use efficiency.
  • DownLoad:Study on evaporation variation of jujube trees under drip irrigation of jujube and cotton intercropping in an arid area.PDF
  • Short-term effects of manipulated throughfall reduction on the quantity and quality of litterfall in a Pinus massoniana plantation
  • Authors:YANG Yujing, LIU Shirong, CHEN Lin, WANG Hui and LU Lihua
  • Abstract:To explore the impacts of precipitation pattern change on forest growth and carbon sequestration under climate change, a manipulation experiment of throughfall reduction was conducted in a Pinus massoniana plantation in southern subtropical China since 2012, which included three 20 m×20 m plots with a 50% throughfall exclusion and their respective control plots. Litterfall samples were collected from January to December every two months in 2016, from five 1 m×1 m aboveground (40 cm) litterfall traps in each plot, and were separated into different components to measure the mass percentage, biomass, and basic chemical properties. The results showed that litterfall quantity and the proportion of needles were both significantly higher than other litterfall components in the plantation (P < 0.05). The short-term manipulated drought did not significantly affect the needle quantity or total litterfall (P > 0.05). Compared to the control, the throughfall treatment enhanced the C content of needle litterfall and N content of fruit litterfall by 27.4 g/kg and 5.1 g/kg, respectively (P < 0.05). The treatment also increased the lignin content of needle litterfall, cellulose content of broadleaf litterfall, hemicellulose content of skin litterfall by 3.9%, 5.2%, and 4.0%, respectively, while it decreased the C and cellulose content of skin litterfall as well as the C:N ratio of fruit litterfall (P < 0.05). The positive correlations between the N and P content of the litterfall, and between the C and lignin content of the litterfall, were both significant (P < 0.05). These results indicated that the short-term experimental throughfall reduction did not significantly alter total litterfall, while it increased the lignin and C content of needle litterfall, in a southern subtropical P. massoniana plantation. Our study further suggests a possible decrease in the decomposition ability of litterfall, which could reduce the input of litter-derived soil carbon in a southern subtropical P. massoniana plantation, under short-term manipulated drought conditions.
  • DownLoad:Short-term effects of manipulated throughfall reduction on the quantity and quality of litterfall in a Pinus massoniana plantation.PDF
  • Quantitative classification and ordination of grassland communities in Lhasa River Valley
  • Authors:YAO Shuaichen, WANG Jingsheng, DING Lubin, BAO Xiaoting, LI Chao, WANG Tong, LIU Wenjing and LI Yanyan
  • Abstract:Alpine grasslands on the Qinghai-Tibetan Plateau play an important role in safeguarding the economic sustainability of local animal husbandry. However, these alpine grasslands have been degraded due to increased human disturbance and changing climate in the past few decades. Quantitative classification and ordination are necessary to reveal how alpine grasslands respond to the changing environments. In this study, the Two-way indicator species analysis (TWINSPAN) was used to classify 23 plots of alpine grassland communities in the Lhasa River Valley. Canonical correspondence analysis (CCA) and detrended canonical correspondence analysis (DCA) were used to clarify the geographical distribution patterns of these alpine grassland communities. Our results indicate that:(1) Alpine meadows in the study area can be classified into 8 subtypes:Elymus nutans + Tripogon bromoides; Carex moorcroftii; Kobresia pygmaea + Carex moorcroftii; Potentilla fruticose + Kobresia pygmaea; Rhododendron primuliflorum + Kobresia pygmaea; Rhododendron primuliflorum + Rhododendron nivale + Kobresia pygmaea; Rhododendron nivale + Kobresia pygmaea; and Kobresia pygmaea. (2) Each subtype identified by TWINSPAN had a specific distribution and boundaries on the DCA ordination diagram, suggesting that DCA ordination can explain the relationship between community composition and environmental factors, (3) The first and second axes of DCA reflected the influences of plot elevation and aspect, respectively, (4) CCA ordination also confirmed that altitude, followed by aspect, was the primary environmental factor controlling the distribution of alpine grassland communities, (5) The CCA of species and TWINSPAN of community subtypes were similar, indicating that the distribution patterns of the grassland community were largely affected by the species distribution pattern. Quantitative analysis is suggested to examine and assess the relative contributions of anthropogenic and natural factors to changes in the Tibetan alpine grasslands in the future.
  • DownLoad:Quantitative classification and ordination of grassland communities in Lhasa River Valley.PDF
  • Effects of topography on the distribution pattern of net primary productivity of grassland in Changji Prefecture, Xinjiang
  • Authors:DU Mengjie, ZHENG Jianghua, REN Xuan, CAI Yarong, MU Chen and YAN Kai
  • Abstract:Xinjiang grassland resources are rich and varied, but as far as current research is concerned, topography has not been fully considered as one of the most important environmental factors affecting vegetation productivity. This study takes Landsat and DEM as data sources, and the object of study is a grassland in Changji Prefecture of the Xinjiang autonomous region. The annual net primary productivity is calculated with the CASA model. The ArcGIS spatial analysis method is used to analyze the distribution of the net primary productivity in Changji Prefecture for the years 2000-2016. The results show that topography plays an important role in the distribution of productivity. The analysis of the influence of elevation, slope, and aspect show that slope is the largest impact factor, followed by aspect, and elevation is the smallest. In the overall characteristics, when the elevation increases by 30 m, the productivity increases by 4.11 g/m2. In the same way, when the slope increases by 1 degree, the productivity increases by -0.225 g/m2. The productivity of the north aspect is the highest (23.23 g/m2), and that of the southeast aspect is the lowest (3.54 g/m2). In years with different productivities, the trend of impacts is the same, but the ranges of variation are different. The three topographic factors have the largest range of change in high-productivity years.
  • DownLoad:Effects of topography on the distribution pattern of net primary productivity of grassland in Changji Prefecture, Xinjiang.PDF
  • Effects of forest compensation policy for public welfare on the spatiotemporal patterns and dynamics of vegetation cover: a case study at Lin'an, Hangzhou City
  • Authors:ZHOU Ting, ZHANG Yong and YAN Lijiao
  • Abstract:Evaluation of the effect of ecological compensation policies is important for improving policy regulations and vegetation recovery. We analyzed the spatiotemporal pattern of vegetation cover from 2001 to 2015 at Lin'an City. We established the land-use change matrix in vegetation degraded area. We created a geodatabase in ArcGIS, including the Normalized Differential Vegetation Index (NDVI), national and provincial boundary of forest compensation policy for public welfare, built-up area, road, elevation, key forest reserves, rivers, and topographic wetness index. Finally, we used the multiple linear regression analysis to estimate the effects of national and provincial forest compensation policy for public welfare, biophysical factors, urbanization, and other human activities on vegetation cover change. Our results show that, during the 2001 to 2015, approximately 97% of the vegetated areas have suffered different levels of decline or degradation, with the moderate level of degradation constituting the largest proportion. The results of multiple linear regressions suggest that policy, elevation, distance to river, distance to key forest reserves, and distance to the center of the town have a significantly negative correlation with vegetation degradation, whereas distance to road and topographic wetness index have a positive correlation with vegetation degradation. Elevation has the greatest effect among the external factors analyzed. Moreover, in each degradation level, the areas where the compensation policy was implemented suffered a lower degradation than the other areas did. Our findings suggest that the implementation of ecological compensation policy plays a positive role in protecting vegetation cover, restricting inappropriate utilization, and improving regional environment quality.
  • DownLoad:Effects of forest compensation policy for public welfare on the spatiotemporal patterns and dynamics of vegetation cover: a case study at Lin'an, Hangzhou City.PDF
  • Gonad differentiation and the effects of temperature on sex determination in Quasipaa spinosa
  • Authors:MEI Yiyun, ZHENG Rongquan, ZHENG Shanjian, YAN Hong, LIU Zhifang, ZHANG Qipeng, WANG Zhigang and HONG Yan
  • Abstract:Monosex cultivation is significant in the breeding of the Chinese spiny frog Quasipaa spinosa. In order to understand the gonadal differentiation of Q. spinosa, the effects of temperature on its gonad differentiation. This paper describes the formation of the primordial gonad and gonadal differentiation of Q. spinosa as determined using histological methods. Some particulars of Q. spinosa gonad differentiation:two types of cells, primordial germ cells (PGCs) and somatic cells, could be distinguished in the germinal ridges; there is a primary cavity which has squamous epithelium on the surface in every primordial gonad, regardless of whether it will become an ovary or a testis, and when the squamous epithelium on the surface disappears gradually, a secondary cavity forms. When PGCs around the cavity begin to mature, primordial gonads begin to differentiate into ovaries; when somatic cells go into the cavity, the cavity disappears gradually, and primordial gonads begin to differentiate into testes. Day 17 to day 80 (Gosner stages 25-26) is a sensitive period for gonadal differentiation in Q. spinosa. Tadpoles were divided into 4 groups from day 1 (Gosner stage 24) on. Every group was cultured under one of four temperatures:(16±1)℃, (23±1)℃, (27±1)℃, and (31±1)℃. The control group was maintained at (23±1)℃. The sex ratio in the control group was 26:24 female:male (the male rate was approximately 50%). In the (16±1)℃ group, the female to male ratio was 33:17, so the male rate only was 34% (P < 0.05). The rate of male gonadal differentiation was progressively higher from (27±1)℃ to (31±1)℃. In the (31±1)℃ group, the male rate was 70% (P < 0.05). These results show that sex determination in Q. spinosa is temperature-sensitive. At higher temperatures, some individuals displayed hermaphroditic characteristics. High water temperatures will induce masculinization.
  • DownLoad:Gonad differentiation and the effects of temperature on sex determination in Quasipaa spinosa.PDF
  • Degree of close spatial-following relationship between four insect pests and their natural enemies studied in a span of two years about “WuNiuZao” tea garden
  • Authors:YU Yan, WANG Zhenxing, LI Shang, BI Shoudong, ZHOU Xiazhi, ZOU Yunding, WANG Jianpan and LANG Kun
  • Abstract:To protect and use of natural enemies and provide scientific sampling methods, in this study, the spatial relationships among the natural enemies of the insect pests Toxoptera aurantii Boyer, Empoasca vitis Gothe, Breuipalpus oboyats, and Monolepta hieroglyphica were investigated in the tea garden of "WuNiuZao" in the Hefei suburban district, China in 2015 and 2016. The reasons for differences in the relationship between the same natural enemies and the pest species in the two years were evaluated. The ranges of spatial dependence (RSDs) of natural enemies were calculated using a geostatistics method, and the spatial relationships among enemies and pests were analyzed using grey relational analysis. A greater relative degree indicates a closer following space about the relationship between natural enemies and pests. The relational grade analysis showed that the three main enemies Neoscona theisi, Tetragnatha maxillosa and Clubiona japonicola Boes. et Str had a close relationshipwith Toxoptera aurantii in spatial-following relationships in the "WuNiuZao" tea garden in 2015. Although the three main enemies Tetragnatha maxillosa, Theridion octomaculatum Boes.et Str., and Tetragnatha maxillosa remained the same during the two years, the sorting was different in 2016. The relational grade analysis showed that the three main enemies Neoscona theisi, Theridion octomaculatum Boes. et Str., and Clubiona japonicola Boes. et Str had close relationship with Empoasca vitis in spatial-following relationships in the "WuNiuZao" tea garden in 2015. The three main enemies included Theridion octomaculatum Boes. et Str, Neoscona theisi, and Tetragnatha syusmata in 2016. Theridion octomaculatum Boes. et Str. and Neoscona theisi remained the same during the two years, but the seating arrangement was different. The relational grade analysis showed that the three main enemies Neoscona theisi, Clubiona japonicola Boes. et Str, and Tetragnatha syusmata had consanguineous relations with Breuipalpus oboyats in spatial-following relationships in the "WuNiuZao" tea garden in 2015. The three main enemies included Tetragnatha squamata Karsch, Clubiona japonicola Boes. et Str, and Theridion octomaculatum Boes et Str. Clubiona japonicola Boes. et Str and Tetragnatha squamata Karsch remained the same during the two years, but the sorting was different. The relational grade analysis showed that the three main enemies, Theridion octomaculatum Boes. et Str, Clubiona japonicola Boes. et Str, and Tetragnatha syusmata had consanguineous relations with Monolepta hieroglyphica in spatial-following relationships in the tea garden in 2015. The three main enemies included Tetragnatha syusmata, Clubiona japonicola Boes. et Str, and Neoscona theisi in 2016. Tetragnatha squamata Karsch and Clubiona japonicola Boes. et Str remained the same during the two years, but the sorting was different. The main reason for the change of the natural enemies of the pests during the two years is the difference in the ratio of the number of individual pests to the number of individual natural enemies:smaller the ratio, closer is the following relationship between predators and pests, which seems to be caused by a shortage in natural enemy species resources.
  • DownLoad:Degree of close spatial-following relationship between four insect pests and their natural enemies studied in a span of two years about “WuNiuZao” tea garden.PDF
  • Seasonal dynamics of macroinvertebrate community structure in a headwater stream in the Changbai Mountains
  • Authors:WANG Lu, YANG Haijun, LI Kun, LI Ling, NAN Xiaofei and ZHANG Zhenxing
  • Abstract:Headwater streams are critical locations with nutrient recycling and energy flow along a river ecosystem, posing vital significance to macroinvertebrate biodiversity maintenance in rivers. However, in China, research upon headwater streams' macroinvertebrate community structure is few, and the report about seasonality of macroinvertebrate community structure in headwater streams of the Changbai Mountains is particularly lacking. By using in-situ sampling in the wild, we attempt to elucidate seasonality of river macroinvertebrates and the major environmental drivers behind in headwater streams of the Changbai Mountains. The results revealed:(1) A total of 90 taxa of river macroinvertebrates were identified, pertaining to 3 classes, 9 orders, and 38 families. Among which, aquatic insects (85 genera) were dominant. Seasonality of the river macroinvertebrates' community structure was manifest, with density and diversity of the macroinvertebrates significantly higher in fall and summer than in winter and spring, reaching minimums in winter. (2) Gather-collectors were dominant functional feeding groups, and then shredders, predators, and scrapers. By contrast, filter-collectors accounted for a little part. The seasonality of different functional feeding groups indicated not in line with each other, despite density and species richness all demonstrated highest in autumn. (3) Water temperature, distribution of leaf litter, and flow velocity were major drivers of seasonal dynamics of river macroinvertebrate communities in the area. Our results may provide a support for addressing the headwater streams ecology in the Changbai Mountains, and ecological restorations of the Songhua River basins.
  • DownLoad:Seasonal dynamics of macroinvertebrate community structure in a headwater stream in the Changbai Mountains.PDF
  • Response of root morphology and biomass of Phragmites australis to soil salinity in inland salt marsh
  • Authors:WANG Jiwei, ZHAO Chengzhang, ZHAO Lianchun, WANG Xiaopeng and LI Qun
  • Abstract:Root morphology and biomass allocation are important features for determining the capacity of root absorption, and the nature of the responses to environmental constraint factors and adaptation strategies have been a hot research topic. However, numerous uncertainties about the effects of soil salinity on the root traits of plants still exist. This study was performed on Phragmites australis community in Qinwangchuan National Wetland Park of Lanzhou. Three different plots with a soil salinity gradient (plot I, Ⅱ, and Ⅲ) were set up from the edge to the center of wetland, which was perpendicular to the bank of the Sha River. The change characteristics of the morphological parameters such as the ratio of root to shoot, total and specific root lengths, root forks, and the average root diameter of P. australis were studied using the combined method of total root excavation along with the Win-RHIZO root analyzer. The results showed that the height, coverage, density, and above-ground biomass of the wetland community decreased gradually with the increase of soil salinity. In addition, the ratio of root to shoot and root forks of P. australis decreased gradually, and the specific and total root lengths of P. australis first decreased and then they subsequently increased whereas the average root diameter showed an opposite trend. The soil salinity was dominated by moderate salinization, and the surface soil salinity showed strong variability. Specifically, the soil salinity of the plots showed a decreasing trend with increasing soil depth, and the variation degree was different. According to the correlation analysis, there was a significant correlation between the soil salinity, total root length, and specific root length (P < 0.01). Furthermore, the soil salinity was significantly correlated with the root/shoot ratio and root forks (P < 0.05), but not the root mean diameter. The P. australis specimens in the inland salt marshes showed the characteristics of sensitive plants. They adapted to the soil environment that had a strong salt variation by modifying their root morphology and changing the biomass allocation strategy. This phenomenon reflected the ecological adaptation mechanism used by wetland plants to cope with multiple environmental selection pressures under adverse stress conditions.
  • DownLoad:Response of root morphology and biomass of Phragmites australis to soil salinity in inland salt marsh.PDF
  • Effects of different vegetation restoration types on the slope difference of soil water content in the Loess Plateau, China
  • Authors:AN Wenming, HAN Xiaoyang, LI Zongshan, WANG Shuai, WU Xing, LÜ Yihe, LIU Guohua and FU Bojie
  • Abstract:Along with large-scale "Grain for Green" in the Loess Plateau of China, the land-use change significantly affected the soil water content (SWC) and its spatial-temporal pattern. In this study, we investigated the hill slopes, and the effects of different vegetation restoration types (abandoned farmlands and black locust forestlands) on the spatial pattern or heterogeneity of the SWC were explored based on the differences in the slope trends of SWC between two vegetation restoration types. The results indicated that the average SWC of black locust forestland slopes was significantly lower than that of the abandoned farmland slopes in both zones. Furthermore, slope differences in the SWC in the black locust forestlands were lower than those in the abandoned farmland slopes. Along the hill slopes, although the SWC both showed decreasing trends from the bottom to top in the two vegetation restoration types, both types also exhibited certain differences in their trends. The decreasing trend of SWC in the abandoned farmland increased with increasing soil depth. Furthermore, the decreasing trend of the abandoned farmland SWC was more obvious in Shaozhongwan of Chang Wu county than it was in Yangjuangou catchment of Yan an. In contrast, the decreasing trend of the black locust forestland decreased with increasing soil depth. Moreover, the decreasing trend in the black locust forestland from the bottom to top was lower than that of the abandoned farmland. In addition, the variation trend of the SWC along slopes in the black locust forestlands showed no obvious differences between the two zones. In summary, although the different rainfall background would lead to differences in SWC, its variation trend along with the hill slopes including the effects attributed to different vegetation restoration types were similar between the two zones. Moreover, the excessive consumption of soil water by the black locust forestland not only led to soil water deficits but also diminished the variation trend of SWC along the slopes. In contrast, the abandoned farmlands maintained relatively positive SWC and spatial patterns. By analyzing the effects of different vegetation restoration types on the variation trends of SWC along the slopes, the soil hydrological effect of different vegetation restoration methods could be enriched. Moreover, our findings could provide a useful reference for the scientific allocation of vegetation during the "Grain for Green" process based on the slopes.
  • DownLoad:Effects of different vegetation restoration types on the slope difference of soil water content in the Loess Plateau, China.PDF
  • Effects of ecological restoration on soil organic carbon components and stability in a red soil erosion area
  • Authors:JIANG Miaohua, LÜ Maokui, LIN Weisheng, XIE Jinsheng and YANG Yusheng
  • Abstract:Composition and dynamics of soil organic carbon (SOC) are important indicators for soil restoration. However, little attention has been paid to SOC dynamics in red soil erosion areas. We conducted an investigation in the surface soil layers (0-10 and 10-20 cm) in Pinus massoniana woodlands with restoration histories of 10 and 30 years respectively. We studied the changes of the contents of soil organic carbon (SOC) fractions, coarse particulate organic carbon (cPOC), fine particulate organic carbon (fPOC), and mineral-associated organic carbon (MOC), as well as the POC/MOC ratios, to determine the effects of ecological restoration in both woodlands compared to bare land and secondary forest. Our results showed that the various types of soil organic carbon in both soil layers significantly increased with time of restoration (P < 0.05). In the stand with 10 years restoration, the soil fPOC increased significantly in the top soil (0-10 cm) which accounted for more than 64.1% of the total SOC content, indicating that the SOC mostly accumulated in the form of fPOC. However, the soil cPOC and MOC had no significant changes. Compared to the stand with 10 years of restoration, in the Pinus massoniana woodland with 30 years of restoration, the soil cPOC and MOC increased significantly in the top layer (< 10 cm), but fPOC did not. The contents of fPOC and MOC also increased significantly in the 10-20 cm layer, but the cPOC contents did not. The results demonstrated that the patterns of SOC sequestration in the process of ecological restoration confirmed the SOC saturation theory. The soil POC/MOC ratio was higher in the top layer than in the deeper layer and initially increased with time of restoration, reaching its highest value in our study in the 10-year stand, then decreased rapidly. The results indicated that the SOC became more stable in subsoil than in topsoil with restoration time, which highlighted that ecological restoration plays a crucial role in long-term sequestration of SOC in red soil erosion areas.
  • DownLoad:Effects of ecological restoration on soil organic carbon components and stability in a red soil erosion area.PDF
  • Responses of soil labile organic carbon and enzyme activity to Spartina alterniflora invasion in estuary wetland of Jiaozhou Bay
  • Authors:ZHANG Hanbing, KONG Fanlong, XI Min, LI Yue and SUN Xiaolin
  • Abstract:The effects of Spartina alterniflora invasion on soil labile organic carbon (LOC) and enzyme (urease, catalase, alkaline phosphatase, invertase) activities were investigated in the Yanghe estuary wetland of Jiaozhou Bay. Soil samples were collected at 0-60 cm depths in different invasion years (0, 1, 5, and 8). The responses of LOC and soil enzyme activity to Spartina alterniflora invasion, and the relationship between them, were assessed. The results showed that Spartina alterniflora invasion significantly increased LOC contents of the surface layer in comparison to that of the mudflat (P < 0.05), and the soil LOC contents increased significantly with the increase of invasion time. Meanwhile, Spartina alterniflora invasion also changed the rule of vertical dynamics of LOC contents. Sample plot LOC first showed an increasing trend, and then decreased along the soil profile except that LOC contents of the two plots increased along the entire soil profile. Spartina alterniflora invasion increased the soil enzyme activities, but it did not change their distribution rule, as they decreased with increasing soil depth. The variation trend of 4 types of enzyme activities changed with the increase of Spartina alterniflora invasion time. The catalase and invertase activities first showed a dramatic increase and then a gradual decrease, but alkaline phosphatase and urease activities gradually increased with the increase in invasion time. Pearson correlation analysis showed that soil labile organic carbon was significantly negatively correlated with enzyme activity, and the correlation decreased with the increase of invasion time; it disappeared after 8 years.
  • DownLoad:Responses of soil labile organic carbon and enzyme activity to Spartina alterniflora invasion in estuary wetland of Jiaozhou Bay.PDF
  • Effect of soil factors after forest conversion on the accumulation of phosphorus species in mid-subtropical forests
  • Authors:ZENG Xiaomin, GAO Jintao, FAN Yuexin, YUAN Ping, BAO Yong, GAO Ying, ZHAO Panpan, SI Youtao, CHEN Yuemin and YANG Yusheng
  • Abstract:Phosphorus (P), a macro-nutrient essential for plant growth, is considered the key factor for maintaining the productivity of subtropical forest ecosystems. Understanding the effects of soil factors on the accumulation of phosphorus species after forest conversion is important in developing management practices that sustain and enhance ecosystem functionality. The objectives of the present study were to evaluate the response of soil phosphorus to forest conversion, and elucidate the mechanisms and environmental factors driving changes in soil phosphorus. The study sites included secondary broadleaved forests of Castanopsis carlesii (SF), human-assisted naturally regenerated forests of Castanopsis carlesii (AR), and plantations of Cunninghamia lanceolata (CF), which were converted from natural forests in the mid-subtropical region of China. Basic physicochemical characteristics, including iron and aluminum oxide content, different phosphorus forms, and acid phosphatase activities, were determined. The results revealed that the soil total P and organic and microbial biomass P levels were significantly higher in AR than in SF or CF. A redundancy analysis indicated that the changes in soil phosphorus were mainly driven by soil moisture, total nitrogen, and amorphous Fe oxides (Feo) in the eluvial horizon, and by acid phosphatase, free Fe (Fed), and total nitrogen in the illuvial horizon. The results suggest that soil biochemical properties and microbial characteristics affect the accumulation of different soil P formations, primarily by changing the soil moisture levels and acid phosphatase activity. In summary, human-assisted naturally regenerated forests converted from natural forests were the most conducive to the storage and supply of nutrients and the sustainable development of ecosystem functionality among the management systems studied. The present study might provide a theoretical basis for assessing forest management practices in mid-subtropical forests.
  • DownLoad:Effect of soil factors after forest conversion on the accumulation of phosphorus species in mid-subtropical forests.PDF
  • Effect of Avena sativa L. on soil enzyme activity and microbe functional diversity under strontium pollution
  • Authors:QI Lin, LI Yanling, ZHAO Wei and WANG Xiaoling
  • Abstract:Strontium (Sr) is a common fission product of U-235 and Pu-239. Radioactive isotopes show heavy metal toxicity and radioactivity. The fate of radionuclides in the environment follows the behavior of stable elements; therefore, the behavior of stable Sr-88 should be regarded as a useful analog for predicting the fate of Sr-90 in the environment. Phytoremediation is an emerging technology whereby plants remove metals from the environment. The ultimate goal of phytoremediation is to eliminate or reduce soil pollutants and restore soil quality. The phytoremediation of contaminated soil can be assessed by evaluating the soil nutrient content and enzyme activity. Biolog technology is used to characterize the functional diversity of the soil microbial community and kinetic characteristics of carbon source utilization, and has been widely applied to determine the effect of heavy metal pollution on microbial communities. In our previous study, 26 cultivars of wheat (Triticum aestivum L.), oat (Avena sativa L.), and barley (Hordeum vulgare L.) were compared to investigate Sr accumulation and distribution for their potential use in phytoremediation. Based on these results, Neimengkeyimai-1 could be used as a model for further research, as a starting point for finding additional effective cultivars. In this experiment, A. sativa ‘Neimengkeyi-1’ was selected as the model plant to evaluate the effect of oat planting on Sr-contaminated soils. Through pot experiments, Sr was added to soils in six treatments:25 mg/kg Sr (CK), 100 mg/kg Sr (L), 250 mg/kg Sr (H), 25 mg/kg Sr + oat (CK+oat), 100 mg/kg Sr + oat (L+oat), and 250 mg/kg Sr + oat (H+oat), respectively. After 30 days of cultivation, the soil enzymes (including invertase, phosphatase, protease, urease, and dehydrogenase) and soil microbial community functional diversity were measured to evaluate the phytoremediation effect of oat on Sr-contaminated soils. The results showed that oat significantly improved the activities of urease and dehydrogenase. Oat significantly increased utilization of the average of 31 carbon sources (average well color development, AWCD) by the soil microbial community and improved the Shannon diversity index (H), Shannon evenness index (E), and carbon source utilization richness index (S), but reduced the Shannon dominance index (D) under Sr pollution. Principal component analysis (PCA) showed that the utilization of carboxylic and polymer carbon sources were, respectively, higher by 24% and 23% in L+oat treatments and by 24% and 13% in H+oat treatments than in non-planting treatments (L+H). The carboxylic and polymer carbon sources were the main carbon sources in the soil microbial community under Sr pollution. A cluster analysis showed that Sr pollution in soils was close to the metabolic soil microbial community characteristics, and planting oat significantly improved the soil environment. These results were consistent with those of soil enzyme activity and the PCA. In conclusion, oat increased enzyme activity and improved the functional diversity of rhizosphere soil microbes in Sr-polluted soil.
  • DownLoad:Effect of Avena sativa L. on soil enzyme activity and microbe functional diversity under strontium pollution.PDF
  • Phospholipidfatty acid (PLFA) analysis of soil microbial community structure with different intensities of grazing and fencing in alpine shrubland
  • Authors:WEI Yingli, CAO Wenxia, LI Jianhong, ZHANG Aimei and LI Xiaolong
  • Abstract:The soil microbial community, which indicates soil quality changes, has been regarded as an early warning and sensitive indicator of soil ecosystem change. The phospholipid fattyacid (PLFA) method was used to study the changing rule and response of the soil microbial community structure to different intensities of grazing and fencing of alpine rhododendron shrubland. The results showed that soil total PLFA, bacterial biomass, actinomycetes biomass, and fungi biomass were significantly reduced with an increase in grazing intensity (P < 0.05). At heavy grazing intensity, soil total PLFA, bacterial biomass,actinomycetes biomass, G+/G- ratio, and the stress index after the fenced treatment were significantly higher than those after the grazing treatment, whereas the bacteria/fungi ratio after the fenced treatment was significantly lower than that after the grazing treatment. At medium grazing intensity, soil total PLFA, bacterial biomass, and bacteria/fungi ratio were significantly higher than those after the grazing treatment, whereas fungal biomass and the stress index were significantly lower than those after the grazing treatment. At light grazing intensity, biomass and biomass ratio after the fenced treatment and those after the grazing treatment were not significantly different. PLFA principal component analysis (PCA) showed that 53.68% of PC1 was composed of straight-chain saturated and unsaturated fatty acids 14:0, 15:0, 10Me16:0, and 18:1ω9c, whereas 51.34% of PC2 was composed of branched-chain saturated and cyclopropane fatty acids i16:0, 16:1ω7c, i17:0, cy17:0, 17:0, 18:1ω9t, 18:0, and cy19:0. Grazing grassland and fenced grassland of different grazing intensities had similar soil microorganisms. The fenced treatment affected the microbial community structure to a greater extent than did the grazing treatment. Correlation analysis showed that soil total PLFA, bacteria biomass, fungi biomass, and actinomycetes biomass were significantly and positively correlated with soil organic carbon and total nitrogen at P < 0.001, whereas bacteria/fungi had a significant and negative correlation with soil organic carbon and total nitrogen (P < 0.001). The above indicated that overgrazing reduces soil microbial activity of alpine shrublands and significantly reduces the soil microbial biomass, the soil microbial community was stable in fenced and moderately grazed areas, and fencing is advantageous to recovery of the soil microbial community in overgrazed grasslands.
  • DownLoad:Phospholipidfatty acid (PLFA) analysis of soil microbial community structure with different intensities of grazing and fencing in alpine shrubland.PDF
  • Allelopathic potential evaluation of different soil decomposition layers in wild Rhododendron irroratum forest
  • Authors:LI Chaochan, QIAN Chenyu, QUAN Wenxuan, TANG Fenghua and OU Jing
  • Abstract:The chemical composition of extractions of different soil layers from a Rhododendron irroratum forest was analyzed to provide basic data on the relationships between the community's natural regeneration barrier and allelopathy and to explain the natural regeneration barrier factors from the perspective of chemical ecology. The allelopathic effects of litter layer (L layer), humus layer (H layer), and soil layer (S layer) extractions were compared using seed germination methods. The organic compounds in the three extractions were assessed using the internal standard method with gas chromatography-mass spectrometry (GC/MS). (1) The seed germination test showed that of the three layers, L layer had the strongest inhibitory effect and its extraction inhibits seed germination, while H layer and S layer had some inhibitory effect that was not significant compared with the control. (2) Thirty-one components were identified from the organic compounds of L layer, H layer, and S layer, in which there were 6, 8, and 8 kinds, respectively, with relative contents of more than 5%. The main allelochemical components of L layer are glycerol and palmitic acid, with relative contents as high as 19.56% and 19.17%; the main allelochemical components of H layer are 2-hydroxypropanoic acid and palmitic acid, with relative contents up to 14.05% and 12.48%; and the main allelochemical components of L layer are palmitic acid and 2-hydroxyacetic acid, with relative contents as high as 14.91% and 12.79%. L layer had the highest contents of allelochemical compounds, and L layer was the main source of soil allelochemicals. The main allelochemicals in H layer and S layer were long-chain fatty acids and organic acids, and the major allelochemicals in L layer were long-chain fatty acids and alcohols. The allelochemicals of Rhododendron community soils might be one of the main reasons for the natural regeneration barrier in this community.
  • DownLoad:Allelopathic potential evaluation of different soil decomposition layers in wild Rhododendron irroratum forest.PDF
  • Natural Capital Science and Practices: Livable Cities and Sustainable Development ——Review on 2018 Natural Capital Project Symposium
  • Authors:
  • Abstract:The 2018 Natural Capital Project Symposium was held at Stanford University from March 19th to 22nd. The Natural Capital Project was initiated by Stanford University, the World Wide Fund for Nature, and the Nature Conservancy. It aims to integrate of value nature provides to society into all major decisions. The symposium officially invited and announced the Research Center for Eco-Environmental Sciences of Chinese Academy of Sciences as a project partner. The conference attracted 363 government officials, NGO members, entrepreneurs, experts and scholars from 33 countries. The two major themes of symposium are livable cities and sustainable development. The symposium included 9 keynotes and 3 parallel tracks. The parallel tracks were summarized into six aspects: livable cities, sustainable development, freshwater and watershed management, coastal resilience, investment standards, model training and exploration. The symposium also featured workshops, and poster presentations. The symposium promoted the scientific development and practical application of ecosystem services, integrated natural capital into the scientific decision-making system, promoted the integration of science and decision-making and promoted sustainable development on a global scale.
  • DownLoad:Natural Capital Science and Practices: Livable Cities and Sustainable Development ——Review on 2018 Natural Capital Project Symposium.PDF

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