Chinese Journal of Applied Ecology

Discussing the basic ecological relations of sand dune vegetation process

LIU Zhimin, YU Haibin, WANG Haiyang

2024, 35(1): 1-7. doi:10.13287/j.1001-9332.202401.029

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Dune is often considered as a degraded ecosystem. Natural vegetation restoration and stable artificial vegetation construction are the basic means restoring dune ecosystem. Based on long-term study of dune ecosystem, by taking into consideration both the philosophical principles of unity of opposites and dynamic change, and related ecological theories, we put forward some ecological relations that should be paid attention to in the study of vegetation assembly from the perspective of the uniqueness of dune ecosystem. We discussed the necessity of coupling relationships of scale-pattern-process and the transformation of synergy-tradeoff relationships, interpreted the importance of distinguishing sand dune stabilized and shifting phases, disturbance and stress, wind erosion and sand burial in the study of vegetation process. We further explored the applied value of niche law or neutral law in the study of dune vegetation process. Finally, we discussed the issues that should be paid attention to in the study of dune vegetation process from the aspects of adaptability to aeolian activities and drought tolerance, physiological and reproductive process, sexual and asexual reproduction of plants. This study would provide theoretical supports for vegetation restoration and stable vegetation construction of dune ecosystem.

Evolution and implementation pathways from desertification prevention and control to sandy land management and use in China

QIAN Guixia, WANG Xiaoxin, LI Wu, ZHANG Qianni

2024, 35(1): 8-16. doi:10.13287/j.1001-9332.202401.030

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The construction of ecological civilization emphasizes holistic protection of “mountain-water-forest-farmland-lake-grassland-sand”, which has become an important concept of desertification prevention projects in arid and semi-arid areas of China. In the past, sandy land management and use have been neglected in desertification prevention and control, in that the links have not been effectively connected and the long-term and efficient desertification prevention has not been realized. Therefore, combining Qian Xuesen's understanding of “deserticulture”, we comprehensively discussed the “long-term achievements” of China's desertification control miracle from the perspective of the historical evolution of the interaction of technology and practice, and the strategic development of policy guidance. Further, we defined the concepts of desertification prevention, desertification control, and sandy land management and use. We analyzed the coupling and coordination relationship between the four links and the scientific principle based on the development of ecological industry chain. Finally, we put forward the policy and market realization pathways, with efficient sandy land management as the core, desertification prevention as the basis, desertification control as the channel, and long-term sandy land use as the foundation. We expected to provide theoretical and practical guidance for creating a new miracle of China's desertification prevention and control.

Shelterbelt construction in the scenario of coordinated development of mountain, river, forest, farmland, lake, grassland, and sandy land ecosystems in semi-arid wind-sand areas: Principles and methods

WU Dedong, LIU Zhimin, CAO Yu

2024, 35(1): 17-24. doi:10.13287/j.1001-9332.202402.009

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We established the systematic concept framework of shelterbelt construction, with “shelterbelts” as the core concern in the construction of integrated ecosystems including mountain, river, forest, farmland, lake, grassland and sandy-land in semi-arid wind-sand areas. In the construction of shelterbelts, it is necessary to adhere to the principles of scientific coordination and systematic management, considering the carrying capacity of water resources, the demand for dust control, the greening and beautification effects, as well as the principle of improving economic benefits. In practice, the construction methods should base on the types and temporal-spatial distribution of shelterbelts, following the shelterbelts construction theory and technology to form different structure and service functions, achieving the functional goals of shelterbelts. By focusing on the key elements including people, forests, grass, fields, water, and sand, we put forward the timeliness, practicality, and scientificity of shelterbelt construction, proposing construction methods for farmland shelterbelts, pastureland shelterbelts, windbreak and sand-fixing forests and protective forest around village (city), which might provide production technical support for the high-quality construction of green ecological barrier in northern China.

Thinking from Horqin Grassland to Horqin Sandy Land

ZHANG Tonghui, CONG Anqi, LIAN Jie, XU Yuanzhi, WANG Ning

2024, 35(1): 25-30. doi:10.13287/j.1001-9332.202401.032

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We systematically elaborated and compared the spatial scope and landscape changes of Horqin Grassland and Horqin Sand Land from their definitions and ranges. Horqin Grassland is an area with geographical units named after Mongolian tribes, but the boundary is unclear. Horqin Sand Land is also an area that borrows tribal names, but has independent topographic and geomorphic units, and clear boundaries. Horqin Grassland and Horqin Sand Land belong to two spatial regions that are both cross and different. The area and range of Horqin Grassland are larger than that of Horqin Sand Land which has obvious regional characteristics, and is a typical and research object area to study the development and restoration of aeolian desertification. Based on those cognition, we summarized the technologies and example models of comprehensive land management and desertification controlling over the years, and finally sorted out what should be focused on in the future to serve the annihilation war against desertification for Horqin Sand Land.

Effects of revegetation on soil nitrogen-fixation and carbon-fixation microbial communities in the Horqin Sandy Land, China

WANG Ziqing, ZHANG Ying, WANG Yang, CUI Ya'nan, CAO Chengyou

2024, 35(1): 31-40. doi:10.13287/j.1001-9332.202401.028

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To determine the diversity of nitrogen-fixing and carbon-fixing microbial groups in aeolian sandy soil and the effects of sand-fixation plantation type on the structures of two microbial groups in the Horqin Sandy Land, we selected six representative sand-fixation vegetations with the same age, including Caragana microphylla, Artemisia halodendron, Salix gordejevii, Hedysarum fruticosum, Populus simonii, and Pinus sylvestris var. mongolica as well as their adjacent natural Ulmus pumila open forest as test objects to investigate the diversities and structures of nifH- and cbbL-carrying microbial communities in soil by high-throughput sequencing technique. The results showed that vegetation type significantly affected soil physical and chemical properties, microbiological activities, diversities and the main compositions of nitrogen-fixing and carbon-fixing microbial communities. The diversity of soil nitrogen-fixing microbial communities under S. gordejevii and P. simonii plantations and that of carbon-fixing microbial communities under P. sylvestris var. mongolica and P. simonii plantations were significantly higher than those of other plantations. Skermanella, Bradyrhizobium, Azospirillum, and Azohydromonas were dominant nitrogen-fixation genera, with the average relative abundance of 22.3%, 21.5%, 20.8%, and 17.8%, respectively. Soil carbon-fixation microbial communities were dominated by Pseudonocardia, Bradyrhizobium, Cupriavidus, and Mesorhizobium, with relative abundance of 22.4%, 18.5%, 10.5%, and 6.0%, respectively. Soil nitrogen-fixing microbial community under C. mirophylla plantation and carbon-fixing communities under S. gordejevii and P. simonii plantations were very close to those of natural U. pumila open forest. Soil organic matter, NH₄⁺-N, and total phosphorus were the direct determining factors for nitrogen-fixing microbial community, while pH, soil moisture, and available phosphorus were main factors influencing carbon-fixing microbial community. These observations potentially provide the scienti-fic foundations for evaluating the ecological benefits of revegetation practice in sandy lands.

Plant community differentiation of desertification region in northwest Liaoning Province, China

CHEN Qing, WANG Jiaxiao, WANG Yifan, WANG Yang, WANG Yan

2024, 35(1): 41-48. doi:10.13287/j.1001-9332.202401.002

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Understanding plant communities in desertification area is the scientific basis of evaluating the local eco-environmental quality and carrying out desertification control. According to longitude, we divided the desertification area in northwest Liaoning Province into three regions: the eastern region (122°50′37″ -123°49′40″ E), the middle region (121°16′41″-122°35′00″ E), and the western region (119°20′03″ -120°02′41″ E), and investigated the plant communities in each region. The results showed that the proportion of forest and canopy density of tree layer increased from the west to the east. Ass. Pinus sylvestris var. mongolica and Ass. Populus sp. in the eastern, Ass. Pinus tabuliformis and Ass. Populus sp. in the middle, as well as Ass. P. tabuliformis and Ass. Prunus sibirica in the western were dominant communities, respectively. The proportion of brush community in the eastern, middle and western was 0, 22.2%, and 28.0%, respectively. Grasslands formed mainly by human disturbance in the eas-tern and middle regions. The total species numbers were 110 in the middle, 88 in the western and 75 in the eastern, respectively. Therophytes were dominant in the eastern and middle with proportions of 68.2% and 66.7%, respectively. Hemicryptophytes were the dominant type (36.3%) in the western region. The proportion of microphanerophyt, nanophanerophyte, chamaephyte, and geophyte increased from the eastern to the western. The species number, Shannon index, and Simpson diversity index of the middle were the highest among the three regions. Pielou evenness index increased gradually from the eastern to the western. Community similarity between the eastern and the western was the lowest, as shown by the β-biodiversity, and the similarity between the middle and the western was the highest. The community type, species number, characteristics of species composition and species biodiversity of the middle region had the characteristics of ecological transition zone. In general, vegetation status in the desertification area of northwest Liaoning Province was in good condition. There were still some problems including the monotonous vertical structure of forest and tree species as well as the serious human interference.

Critical influencing factors on vegetation productivity in sandy land of the Northwestern Liaoning Province,China

LIU Hongshun, BU Rencang, WANG Zhengwen, CHANG Yu, XIONG Zaiping, QI Li, GAO Yue

2024, 35(1): 49-54. doi:10.13287/j.1001-9332.202401.009

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To reveal the key factors influencing vegetation productivity in sandy lands, we conducted a comprehensive analysis of vegetation productivity on regional scale, pixel scale, and plot scale of the sandy lands in northwes-tern Liaoning Province, based on soil physicochemical data, topographical data, climate data, and the intrinsic characteristics of vegetation. On the regional scale, we established a random forest model to explore the impact of topographical factors, climate factors, and vegetation characteristics on vegetation productivity. On the pixel scale, we performed a correlation analysis between vegetation cover and climate factors. On the plot scale, we combined the physicochemical properties of 234 soil samples with topographical factors and vegetation characteristics, and utilized the random forest model to calculate the importance values of each factor. The results showed that soil nutrients could explain 24.8% of the spatial variation in net primary productivity when other factors were excluded. When introducing topographical factors into the model, the model could explain 40% variation of net primary productivity. When further incorporating fractional vegetation coverage and leaf area index into the model, the model could explain 72.8% variation of net primary productivity. Our findings suggested that fractional vegetation coverage and leaf area index were the most influential factors affecting vegetation productivity in this area. Topographical factors ranked second, followed by climate factors, which had a relatively small impact.

Effects of different fertilization patterns on soil improvement and vegetation restoration of desertified grassland in northwest Liaoning Province, China

ZHANG Xiuying, CAI Jiangping, WANG Cong, JIANG Zhiyang, LI Hui, WANG Zhengwen, JIANG Yong, ZHANG Yuge

2024, 35(1): 55-61. doi:10.13287/j.1001-9332.202401.016

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Improving soil fertility is one of the key approaches for ecological restoration of the wind-sand area in northwest Liaoning Province. Taking wind-sand area in northwest Liaoning Province as test object, we conducted a fertilization experiment with treatments of inorganic fertilizer (nitrogen, phosphorus and potassium fertilizers), organic fertilizer, combined application of organic and inorganic fertilizers, and organic fertilizer combined with a biologically organic matrix (γ-polyglutamic acid), and no fertilizer as control. We measured soil organic matter content and extractable cations concentrations, vegetation coverage, and biomass under different fertilization treatments and determine the suitable fertilization mode. The results showed that compared to the control, inorganic fertilizer rapidly increased vegetation coverage and biomass, but high levels of inorganic fertilizer (150 kg N·hm^-2) led to soil acidification and Ca²⁺ leaching. Organic fertilizer increased soil organic matter content, exchangeable K⁺, Ca²⁺, and Mg²⁺ contents, as well as coverage and biomass vegetation, especially combined with γ-polyglutamic acid. Overall, the combination of low levels of inorganic fertilizer (50 kg N·hm^-2) and moderate levels of organic fertilizer (30000 kg·hm^-2) was the best fertilization practice for the rapid and stable restoration of grassland in wind-sand area. Moreover, the extra addition of γ-polyglutamic acid (60 kg·hm^-2)could effectively improve soil fertility.

Characteristics of vegetation and soil in Caragana korshinskii plantations in the hilly and sandy areas of northwestern Shanxi Province, China

WANG Guohua, WANG Jiaqi, LIU Jing

2024, 35(1): 62-72. doi:10.13287/j.1001-9332.202401.004

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We investigated the changes of soil nutrients and plant communities in the artificial sand fixation forests of Caragana korshinskii with different ages. The results showed that soil organic carbon and soil total nitrogen contents increased with the stand ages, and were significantly higher in 40 and 50 year-old than other ages. Soil organic carbon and total nitrogen contents recovered much faster in the surface layer (0-10 cm) than in others. Soil nutrient stoichiometric ratios (C:P, N:P) in the 0-10 cm soil layer differed significantly among different stand ages. With the increases of stand age, C and N contents in C. korshinskii leaves increased significantly, and reached the maximum at 50 year-old. Leaf P content increased first and then decreased, being maximum at 18 year-old. Leaf C:N first increased and then decreased, being maximum at 12 year-old. The contents of photosynthetic pigments and leaf C:P and N:P decreased first and then increased, being minimum at 18 year-old. C. korshinskii was mainly influenced by N availability before 40 year-old, but mainly limited by P after. The species number, density, and vegetation cover of annual and perennial herbaceous plants increased with stand ages, and the community shifted from a simple shrub plant community to a complex shrub-herb community. The biomass of C. korshinskii and herbaceous plants increased significantly with stand age, and had a significant positive correlation with the contents of soil organic carbon, total nitrogen and N:P.

Assessment of the current invasive situation of alien plants in semi-arid area of Northeast China

ZHANG Yue, MA Weige, LIU Gue, ZHOU Quanlai, GUO Jia, CAO Wei

2024, 35(1): 73-79. doi:10.13287/j.1001-9332.202401.001

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Alien invasive plants have been found in the semi-arid region of Northeast China for a long time, but the overall invasion situation is rarely reported. In this study, we established a database of alien invasive plants in the semi-arid area of Northeast China through field investigation, specimen collection, research of specimen online information platform and literature. The results showed that there were 34 species of alien invasive plants belonging to 26 genera and 10 families in the semi-arid area of Northeast China, among which the Composite family had the largest number of richness, with 9 genera (34.6%) and 11 species (32.4%). There were 15 species (44.1%) in 11 genera (42.3%) of Legumes, Solanaceae and Gramineae. In all the alien invasive plants, 33 species were herbaceous plants, being overwhelmingly dominant (97.1%). There were both 7 species of countrywide invasive plants with invasive grade 1 and 2, each accounting for 20.6% of the total. The number of species with invasive grade 4 was the largest, 17 species, accounting for 50% of the total. The invasive plants originated in North America and Europe was the most, accounting for 64.7%, while those from South America, Asia and Africa accounted for 35.3%. Totally, 44.1% of all the invasive alien plants were intentionally introduced, while 55.9% were unintentionally introduced. In the semi-arid area of Northeast China, 81.3% of the counties (cities) had the distribution of alien invasive plants, and the invasion situation was very serious.

Spatio-temporal variations of vegetation cover in semi-arid regions and its response to climate change: A case study of Xilin Gol, Inner Mongolia, China

LI Jingzhong, XIN Zhenhua, XIE Xiao, XUE Bing, REN Wanxia

2024, 35(1): 80-86. doi:10.13287/j.1001-9332.202401.020

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The quantitative analysis of spatio-temporal variations of vegetation cover and its correlation with climate are of great significance for understanding of ecological environment, ecological civilization construction, and sustainable development in semi-arid areas. We investigated the spatio-temporal variations of normalized difference vegetation index (NDVI) and its response to climate change during 2000-2020 in Xilin Gol, Inner Mongolia, by using trend analysis, regression analysis and partial correlation analysis based on the data of MODIS-NDVI, tempe-rature, precipitation, digital elevation model. The results showed that vegetation cover in Xilin Gol had been increased from 2000 to 2020, which generally included three phases, i.e., stable fluctuation, rapid growth, and steady growth. The mean NDVI showed a zonal increasing distribution from southwest to northeast, and had a strong correlation with elevation and population density in Xilin Gol region. The high values of NDVI were mainly in the east, with a significant increasing trend, and the low values were in the southwest, with a local degradation. The sensitivity of vegetation cover to climate change showed spatial and temporal variations. The spatial variation of vegetation was more sensitive to temperature and the interannual variation was sensitive to annual precipitation. In summary, vegetation cover improved overall in Xilin Gol, but there was degradation in some areas. We should formulate differentiated and precise vegetation restoration and ecological environmental protection policies.

Spatial and temporal distribution characteristics of extreme wind and its effect on wind erosion in Northeast China

LI Fanghao, FAN Haoming, SHI Hao, XU Xiuquan

2024, 35(1): 87-94. doi:10.13287/j.1001-9332.202401.024

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Under the background of climate change, extreme wind events occur frequently in Northeast China, and the soil erosion caused by these extreme wind events has attracted progressively more attention from scholars. We used the methods of linear analysis, Sen+Mann-Kendal trend analysis, and Kriging interpolation to analyze the spatial and temporal characteristics of extreme wind in Northeast China from 2005 to 2020, and used the RWEQ wind erosion estimation model to calculate the annual soil wind erosion of typical wind erosion sites and wind erosion under extreme wind conditions. The results showed that the extreme wind frequency in Northeast China presented a significant upward trend from 2005 to 2020, with an increase of 2.9 times·a^-1. The annual average extreme wind frequency in Northeast China ranged from 1 to 49 times·a^-1, and the high frequency areas were distributed in the northwest of Xilin Gol, the west of the Hulunbuir Plateau, and the northeast of Changbai Mountain. The average contribution rate of extreme wind to soil wind erosion in four typical sites (Xilinhot, New Barhu Right Banner, Nenjiang, and Tongyu) was 31%.

Effects of coal mine waste dump on soil seed bank and vegetation distribution pattern

LIN Yachao, GUO Xiaoping, LI Wenye, YANG Fan, LUO Chao, HAO Jiahang, WU Yuxi

2024, 35(1): 95-101. doi:10.13287/j.1001-9332.202401.005

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Long-term occupation of coal gangue dumping sites (CGDS) may destroy ecological environment of nearby area. However, how the CGDS affects the distribution pattern of soil seed banks and vegetation in the nearby area is not clear. In this study, we investigated soil seed bank and vegetation at different distances from the second CGDS of Yangchangwan in Ningdong mining area, Lingwu, Ningxia. The results showed that soil seed bank was mainly distributed in 0-10 cm layer and decreased with increasing soil depth. Species richness of soil seed bank and vegetation first increased and then tended to be stable with increasing distance to the CGDS. The influence range of CGDS on soil seed banks was 300-500 m and was 100-300 m on aboveground vegetation. The CGDS did not affect the vertical distribution pattern of soil seed bank, but significantly affected the horizontal distribution pattern of soil seed banks and aboveground vegetation. The key area of vegetation restoration around the CGDS was between 100 m and 300 m.

Soil microbial carbon pump conceptual framework 2.0

ZHU Xuefeng, KONG Weidong, HUANG Yimei, XIAO Keqing, LUO Yu, AN Shaoshan, LIANG Chao

2024, 35(1): 102-110. doi:10.13287/j.1001-9332.202401.018

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Microorganisms are essential actors in the biogeochemical cycling of elements within terrestrial ecosystems, with significant influences on soil health, food security, and global climate change. The contribution of microbial anabolism-induced organic compounds is a non-negligible factor in the processes associated with soil carbon (C) storage and organic matter preservation. In recent years, the conceptual framework of soil microbial carbon pump (MCP), with a focus on microbial metabolism and necromass generation process, has gained widespread attention. It primarily describes the processes of soil organic C formation and stabilization driven by the metabolic activities of soil heterotrophic microorganisms, representing an important mechanism and a focal point in current research on terrestrial C sequestration. Here, we reviewed the progress in this field and introduced the soil MCP conceptual framework 2.0, which expands upon the existing MCP model by incorporating autotrophic microbial pathway for C sequestration and integrating the concept of soil mineral C pump. These advancements aimed to enrich and refine our understanding of microbial-mediated terrestrial ecosystem C cycling and sequestration mechanisms. This refined framework would provide theoretical support for achieving China's “dual carbon” goals.

Advances in the research of transformation and stabilization of soil organic carbon from plant and microbe

YANG Yang, WANG Baorong, DOU Yanxing, XUE Zhijing, SUN Hui, WANG Yunqiang, LIANG Chao, AN Shaoshan

2024, 35(1): 111-123. doi:10.13287/j.1001-9332.202401.011

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Soil organic carbon (SOC) is the core component of terrestrial carbon (C) sink. Exploring the transformation and stabilization mechanism of SOC is key to understand the function of terrestrial C sink which copes with climate change. The traditional perspective is that plant residues are the initial source of SOC. The new concept of “soil microbial C pump” emphasizes that the synthesized products of soil microbial assimilation are important contributors to the stable SOC. This provides a new insight to the sequestration mechanism of SOC. Due to the complex and variable decomposition process of plant residues and the high heterogeneity of microbial residues, the transformation and stabilization mechanism of plant residues and microbial residues into SOC is still unclear. We reviewed research progress in plant and microbial residues, and introduced the characterization methods of quantification and transformation of plant residues and microbial residues, and also summarized the new findings on the transformation of plant and microbial residues into SOC. We further discussed the contribution and driving factors of microbial and plant-derived C to SOC. Finally, we prospected the future development direction and research focus in this field. This review would provide the scientific reference for the research of soil C sequestration in terrestrial ecosystem.

Accumulation of microbial necromass carbon and their contribution to soil organic carbon in different vegetation types on the Loess Plateau, Northwest China

SHEN Jikai, HUANG Yimei, HUANG Qian, XU Fengjing

2024, 35(1): 124-132. doi:10.13287/j.1001-9332.202401.014

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Microbial necromass carbon (MNC) is an important contributor to soil organic carbon (SOC). Soil carbon storage has increased significantly since the return of farmland to forestland (grassland) on the Loess Plateau. However, the contribution of MNC to SOC accumulation in different vegetation types and the influence factors remain unclear. Herein, we used the biomarker (amino sugar) technique to determine the MNC content and analyzed the influencing factors in 0-5 cm and 5-20 cm soil layers of natural grassland, shrubland (Caragana microphylla), and forestland (Quercus liaodongensis) in the Loess Plateau. The results showed that: 1) the soil pH decreased significantly from grassland to shrubland and then to forestland within the same soil layer. However, the SOC, total nitrogen (TN), microbial biomass carbon (MBC), and microbial biomass nitrogen (MBN) contents showed a reverse trend, with forestland displaying the highest values followed by shrubland and then grassland. The 0-5 cm had significantly higher values than the 5-20 cm depth. 2) The MNC contents varied 0.69-16.41 g·kg^-1 in the two soil horizons of the three vegetation types. There were significant increases in the contents of bacterial necromass carbon (BNC), fungal necromass carbon (FNC), and MNC in the 0-5 cm soil from grassland, shrubland to forestland. The contents of MBC were 1.9 times higher in forestland than in shrubland, and 3.2 times higher in shrubland than in grassland. In the 5-20 cm soil layer, the contents of FNC and MBC were significantly higher in the forestland than in the shrubland and grassland. The FNC content was significantly higher than that of the BNC, ranging from 1.16 to 9.83 times greater than the BNC. 3) The contribution of MNC to SOC was 0.6 and 0.7 times higher in shrubland and forestland than in grassland, respectively, with FNC accounting for 15.2%-42.7%, and BNC accounting for 1.4%-7.4%. 4) pH, TN, MBC, and MBN were important factors that influenced MNC accumulation. In summary, the variation in vegetation type altered soil nutrients, microbial activity, and soil pH, resulting in forestland and shrubland being more beneficial to the formation and accumulation of MNC, which was dominated by fungi, compared to grassland.

Effect of drainage on microbial transformation processes of soil organic carbon in two typical wetlands of China

JIA Juan, LI Xingqi, FENG Xiaojuan

2024, 35(1): 133-140. doi:10.13287/j.1001-9332.202401.013

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Wetlands store one third of global soil organic carbon (SOC) and are strongly affected by artificial drainage. The impact of drainage-induced water-table decline on carbon cycling in different wetlands, particularly microbial transformation processes, remains unclear. To address this knowledge gap, we collected soil samples from two typical wetlands of China (a nutrient-poor bog located in Dajiuhu and a nutrient-rich fen in Hongyuan) and conducted an incubation experiment with the addition of ¹³C-labeled glucose to analyze the effects of short- and long-term drainage on SOC decomposition, extracellular enzyme activity, microbial carbon use efficiency (CUE), and microbial carbon accumulation efficiency (CAE). The results showed that both short- and long-term drainage significantly increased SOC decomposition rates in both wetlands (from 1.47 μg C·g^-1·h^-1 in submerged soils to 2.47 μg C·g^-1·h^-1 in drained soils), microbial biomass carbon derived from glucose (from 0.21 mg C·g^-1 to 1.00 mg C·g^-1) and CAE (from 0.29 to 0.73), but did not alter CUE (ranging from 0.34 to 0.86). Long-term drainage increased α-glucosidase activity in the Dajiuhu wetland and decreased β-glucosidase and phenol oxidase activities in the Hongyuan wetland. In conclusion, drainage enhanced the ‘microbial carbon pump' and its efficiency in wetlands mainly via increasing microbial intracellular metabolism (including respiration), but also acce-lerated SOC decomposition.

Effects of mixed broadleaved tree species with pure Pinus massoniana plantation on soil microbial necromass carbon and organic carbon fractions

QIN Zhenkai, LIU Runhong, HE Peng, WANG Cong, NIE Yanxia, SHEN Weijun

2024, 35(1): 141-152. doi:10.13287/j.1001-9332.202401.015

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Mixing native broadleaved tree species is a widely used method for renovating Pinus massoniana plantations. Soil microbial necromass carbon and organic carbon fractions are important parameters for evaluating the impacts of tree species mixing and soil organic carbon (SOC) stability. However, their responses to the mixing and renovation of P. massoniana plantation has not been understood yet. Here, we selected a pure P. massoniana plantation (PP) and a mixed P. massoniana and Castanopsis hystrix plantation, with ages of 16 (MP16) and 38 years (MP38), respectively, as the research objects. We quantified soil physical and chemical properties, microbial necromass carbon content, and organic carbon components at different soil layers to reveal whether and how the introduction of C. hystrix into P. massoniana plantation affected soil microbial necromass carbon and organic carbon components. The results showed that the mixed P. massoniana and C. hystrix plantation significantly reduced fungal necromass carbon content and the ratio of fungal/bacterial necromass carbon in the 0-20 cm and 20-40 cm soil layers. There were no significant differences in microbial necromass carbon contents, bacterial necromass carbon contents, and their contributions to SOC among the different plantations. The contribution of fungal necromass carbon to SOC was higher than that of bacterial necromass carbon in all plantation types. The contribution of soil mineral-associated organic carbon (MAOC) to SOC was higher than that of occluded particulate organic carbon (oPOC) and light-free particulate organic carbon (fPOC) for all plantation types. Mixing the precious broadleaved tree species (i.e., C. hystrix) with coniferous species (P. massoniana) significantly increased MAOC content and the contribution of MAOC, oPOC, and fPOC to SOC in the 0-20 cm and 20-40 cm soil layers. The MAOC of MP38 was significantly higher than that of PP in all soil layers and the MAOC of MP38 stands were significantly higher than MP16 stands in the 20-40 cm, 40-60 cm, and 60-100 cm soil layers, indicating that hybridization enhanced SOC stability and that the SOC of MP38 stands were more stable than MP16 stands. SOC and total nitrogen contents were the main environmental factors driving the changes in soil microbial necromass carbon, while soil total nitrogen and organically complexed Fe-Al oxides were the primary factors affecting organic carbon fraction. Therefore, SOC stability can be enhanced by introducing native broadleaved species, such as C. hystrix, during the management of the P. massoniana plantation.

Influencing mechanism of stand age to the accumulation of microbial residue carbon in the Pinus masso-niana plantations

HU Jianwen, LIU Changfu, GOU Mengmeng, CHEN Huiling, LEI Lei, XIAO Wenfa, ZHU Sufeng, HU Ruyuan

2024, 35(1): 153-160. doi:10.13287/j.1001-9332.202401.041

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Clarifying the accumulation pattern of soil microbial residue carbon and its contribution to soil organic carbon (SOC) across stand age is helpful to understand the mechanism underlying soil carbon cycling. In this study, we analyzed the differences of amino sugar content, physicochemical properties and microbial composition in surface soil (0-10 cm) in young (6 a), middle-aged (13 a), near-mature (29 a), mature (38 a) and over-mature (57 a) Pinus massoniana plantations of subtropical China, quantified the microbial residue carbon content and its contribution to SOC, and discussed the mechanism. The results showed that SOC, total nitrogen, amorphous iron oxide and leucine aminopeptidase contents in the middle-aged plantation were significantly lower than those in the mature plantation. Soil pH and fungal/bacteria in young plantation were significantly higher than those in other age groups. Across the stand age gradient, the ranges of microbial, fungal and bacterial residue carbon were 7.52-14.63, 4.03-8.00 and 3.48-6.63 g·kg^-1, respectively. The contents of all the residue carbon were significantly higher in the mature plantation than that of the middle-aged plantation, which were positively affected by soil total nitrogen content. The contribution of microbial, fungal, and bacterial residue carbon to SOC was 59.7%-72.3%, 33.4%-45.6%, and 24.3%-30.8%, respectively. The contribution of fungal residue carbon to SOC in young plantation was significantly higher than that in other age groups, and the contribution of bacterial residue carbon to SOC in middle-aged plantation was significantly higher than that in young and near-mature plantations, both of which were affected by soil inorganic nitrogen. Fungal residue carbon content was 1.2-1.7 times as that of bacterial residue carbon content, and dominated for the accumulation of microbial residue carbon. Results of the partial least squares model showed that stand age, soil environmental factors (such as leucine aminopeptidase, amorphous iron oxide, pH, and total nitrogen), bacterial residue carbon, fungal residue carbon and the contribution of bacterial residue carbon to SOC had total effects on the contribution of fungal residue carbon to SOC (-0.37, -1.16, 0.90, 1.09, and 0.83, respectively). In conclusion, stand age promoted the accumulation of microbial residue carbon but did not increase its contribution to SOC.

Distribution characteristics of microbial necromass carbon along soil profiles in different restoration periods of Caragana korshinskii in mountainous areas of Southern Ningxia, China

ZHANG Yuhan, LI Yao, ZHOU Yue, LIU Chunhui, AN Shaoshan

2024, 35(1): 161-168. doi:10.13287/j.1001-9332.202401.017

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Microbial necromass, an important and stable source of soil organic carbon (SOC), is an important index to evaluate the contribution of microorganisms to SOC transformation and accumulation. It is not clear about the accumulation of microbial necromass in deep soil layer and its contribution to SOC during the restoration process of Caragana korshinskii forests. Combined with the biomarker method, we investigated the carbon contents of bacte-rial, fungal, and microbial necromass in the soil profiles (0-100 cm) of C. korshinskii forests in 16, 28, and 38 years of restoration, with natural grassland as control. We further examined the contribution of microbial necromass to soil organic carbon. The results showed that: 1) Along the soil profile (0-100 cm), the contents of fungal necromass carbon (FNC), bacterial necromass carbon (BNC), and microbial necromass carbon (MNC) significantly decreased with increasing soil depth in natural grassland and C. korshinskii forests. Except for the significant decrease in FNC/SOC, BNC/SOC, and MNC/SOC in the soil of C. korshinskii forests in 38 years of restoration, FNC/SOC and MNC/SOC generally showed an increasing trend followed by a decreasing trend in other plots, while BNC/SOC gradually decreased. 2) With the increases of restoration years, the contents of FNC, BNC, and MNC significantly decreased in C. korshinskii forests. FNC/SOC and MNC/SOC showed an overall increasing trend followed by a decreasing trend, while BNC/SOC gradually decreased. 3) The average contribution of microbial necromass carbon to SOC was highest in C. korshinskii forests in 28 years of restoration (35.0%), followed by C. korshinskii forests in 16 years of restoration (33.5%), natural grassland (31.0%), and C. korshinskii forests in 38 years of restoration (28.6%). In conclusion, when the restoration years of C. korshinskii forests are 16, the contents of microbial necromass carbon and their contributions to SOC are higher compared to natural grassland, which are beneficial for SOC sequestration.

Effects of thinning on accumulation of soil microbial residue carbon of Picea asperata plantations in sub-alpine region of western Sichuan, China

JING Yanli, LI Xuhua, ZHANG Yuan, ZHANG Xinyue, LIU Mei, FENG Qiuhong

2024, 35(1): 169-176. doi:10.13287/j.1001-9332.202401.040

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Microbial residues are an important component of soil organic carbon (SOC). It is unclear how long-term thinning affects the accumulation characteristics of microbial residue carbon (C). We analyzed the differences in soil physicochemical properties, microbial communities, extracellular enzyme activities, and microbial residue C in topsoil (0-10 cm) and subsoil (20-30 cm) in Picea asperata plantation of non-thinned (control, 4950 trees·hm^-2) and thinned for 14 years (1160 trees·hm^-2) stands, aiming to reveal the regulatory mechanism of thinning on microbial residue C accumulation. The results showed that thinning significantly increased SOC content, total nitrogen content, available phosphorus content, the proportion of particulate organic C, soil water content, C-cycle hydrolase, and acid phosphatase activities, but significantly reduced the proportion of mineral-associated organic C. Thinning significantly affected the content of fungal and microbial residue C, and the contribution of microbial residue C to SOC, and these effects were independent of soil layer. The content of fungal and microbial residue C was 25.0% and 24.5% higher under thinning treatments. However, thinning significantly decreased the contribution of microbial residue C to SOC by 12.3%, indicating an increase in the proportion of plant-derived C in SOC. Stepwise regression analysis showed that total nitrogen and soil water content were key factors influencing fungal and micro-bial residue C accumulation. In summary, thinning promoted microbial residue C sequestration by altering soil pro-perties and changed the composition of SOC sources.

Response of soil microbial necromass carbon to litter and root carbon inputs in a mid-subtropical Castanopsis carlesii plantation

WANG Cuijuan, LIU Xiaofei, YANG Liuming, JIA Shuxian

2024, 35(1): 177-185. doi:10.13287/j.1001-9332.202401.012

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Microbial necromass carbon (MNC) is a crucial source for stable soil carbon pool, and understanding its response to carbon inputs from both aboveground (litter) and belowground (roots) in subtropical forest soils is essential for assessing soil carbon stocks in global ecosystems. In a Castanopsis carlesii plantation at the Sanming Forest Ecosystem National Observation and Research Station in Fujian Province, we conducted an experiment with five treatments, including root removal (NR), aboveground litter removal (NL), no litter input (removals of both aboveground litter and roots, NI), double aboveground litter addition (DL), and control (CK). After seven years, we collected soil samples in the 0-10 cm soil layer to examine changes in MNC content and its contribution to soil organic carbon (SOC). Results showed that NR treatment reduced MNC, bacterial necromass carbon (BNC), and fungal necromass carbon (FNC) by 15.9%, 20.2%, and 14.5%, respectively, while other treatments did not induce significant changes. The NR, NL, NI, and DL treatments did not affect the contributions of BNC, FNC, and MNC to SOC. Correlation and path analyses revealed that litter and root carbon input treatments could alter the MNC content directly or indirectly through changing soil available substrates and microbial community structure. Our results suggested that roots exert a stronger influence on the maintenance of MNC than aboveground carbon source in the mid-subtropical plantations.

Effect of seasonal distribution in precipitation on soil nitrogen mineralization in a subtropical forest

JI Yongkang, MA Nan, ZHANG Hui, LI Cuihuan, MA Yuandan, WU Qiqian, LI Yan

2024, 35(1): 186-194. doi:10.13287/j.1001-9332.202401.008

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Soil N mineralization is a key process of nutrient cycling in ecosystems. The mechanism of the seasonal distribution of precipitation on soil N mineralization remains unclear. We conducted a precipitation manipulation experiment in a subtropical forest in the middle and lower reaches of the Yangtze River in China from 2020 to 2022, with three treatments, including control (CK), decreased precipitation in the dry season with extremely increased precipitation in the wet season (T₁), and decreased precipitation in the dry season with proportionally increased precipitation in the wet season (T₂). With in situ resin core method, we explored the effect of seasonal distribution of precipitation on soil N mineralization. The results showed that T₁ and T₂ significantly decreased dry season net nitrification rate by 57.9% and 72.5% and the net N mineralization rate by 82.5% and 89.6%, respectively, and significantly increased wet season net nitrification rate by 64.3% and 79.5% and net N mineralization rate by 64.2% and 81.1%, respectively. Proportionally increased precipitation in the wet season was more conducive to soil N mine-ralization process than extremely increased precipitation in the wet season. Results of the structural equation model showed that change in seasonal distribution of precipitation could significantly affect soil N mineralization processes in the subtropical forest by changing soil water content, ammonium nitrogen, microbial biomass nitrogen, and soil C:N. Our results had important reference for understanding soil nitrogen cycling and other ecological processes, and were conducive to more accurate assessment on the impacts of future changes in seasonal precipitation pattern on subtropical forest ecosystems.

Seasonal dynamics in photosynthetic characteristics and growth of Cunninghamia lanceolata saplings and their response to soil warming

ZHANG Yating, YE Wangmin, XIONG Decheng, WU Chen, HUANG Jinxue, CHEN Shidong, YANG Zhijie

2024, 35(1): 195-202. doi:10.13287/j.1001-9332.202401.006

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In order to understand the response and adaptation mechanisms of photosynthetic characteristics and growth for Cunninghamia lanceolata saplings in the subtropical region to global warming, we conducted the root-box warming experiment (ambient, ambient+4 ℃) at the Sanming Forest Ecosystem National Observation and Research Station in Fujian Province to investigate the effects of soil warming on the photosynthetic characteristics and growth of C. lanceolata saplings in different seasons. The results showed that the net photosynthetic rate (P_n) and stomatal conductance (g_s) of C. lanceolata significantly decreased in summer compared with in spring and autumn. Soil warming had no effect on the P_n and g_s of C. lanceolata. However, the interaction between warming and season significantly impacted the leaf water use efficiency (WUE). The tree height and ground diameter growth of C. lanceolata significantly increased in spring compared with in summer and autumn. Warming significantly reduced ground diameter growth, and it diminished the net diameter growth by 48.1% in autumn. However, warming had no impact on the tree height growth of C. lanceolata in each season. The specific leaf area, soluble sugar, and non-structural carbohydrates contents of C. lanceolata significantly improved in summer and autumn compared with in spring. Warming had rarely influence on leaf functional traits in each season. In conclusion, the response of photosynthesis for C. lanceolata to soil warming was insignificant. The photosynthesis of C. lanceolata exhibited significant seasonal dynamics, primarily controlled by g_s. C. lanceolata adapted to soil warming by adjusting WUE, and it adjusted to high temperatures and drought stress in summer by increasing soluble sugar content and specific leaf area. The effect of warming on ground diameter growth of C. lanceolata was primarily driven by soil moisture. The seasonal difference in the growth of C. lanceolata was influenced by the photosynthesis of C. lanceolata and the trade-off between the utilization and storage of photosynthetic products.

Fire resistance of 15 main economic tree species in Liangshan Prefecture, Sichuan, China.

LI Shuhui, WU Yan, SUN Zhidong, CHEN Jien, YING Dengyu, HUANG Yueyue, JIN Yitang, LI Zhichao

2024, 35(1): 203-211. doi:10.13287/j.1001-9332.202401.003

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Liangshan Prefecture is one of the three major forest areas in Sichuan Province and one of the three major disaster areas of forest fire. We measured the physicochemical properties and combustion performances of different organs (leaves and branches) of 15 main economic tree species in Liangshan, and analyzed the bioecology characteristics, silviculture characteristics and value characteristics of different tree species. We investigated the fire resistance of different tree species to screen out fire-resistant species suitable for economic forest development in Liangshan Prefecture, and improve the biological fire prevention ability. The seven physicochemical properties and combustion performances indices of 15 tree species showed significant differences. Except for crude ash and lignin, the weights of moisture content, caloric value, ignition point, crude fat, and crude fibre of leaves were higher than those of branches. Crude fibre index of leaves (9.6%) and the crude ash index of branches (9.9%) were the highest weight indices of the two organs, respectively. Based on the fire resistance, we divided all the species into three classes, i.e., class Ⅰ (excellent fire-resistance trees) Juglans regia and Morus alba; class Ⅱ (better fire-resistant trees) Sapium sebiferum, Mangifera indica, Phyllanthus emblica, Eriobotrya japonica, Ligustrum lucidum, Castanea mollissima, and Punica granatum; class Ⅲ (poor fire-resistant trees) Pinus armandii, Illicium simonsii, Morella rubra, Sapindus mukorossi, Olea europaea and Camellia oleifera. J. regia and M. alba had fireproof solid performance and could be used as the preferred species for fireproof economic forest in Liangshan region. It was suggested that to use class Ⅰ to Ⅱ fire-resistant tree species built the main fireproof isolated forest belt, and pay attention to fire prevention after planting class Ⅲ tree species in a large area.

Characteristics of anion and cation in rhizosphere soil of saline grassland in North China under different nitrogen addition levels

CHANG Jie, JU Xin, YI Likai, NING Yanan, DIAO Huajie, HAO Jie, WANG Changhui, DONG Kuanhu

2024, 35(1): 212-218. doi:10.13287/j.1001-9332.202401.007

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We investigated the effects and mechanisms of nitrogen additions (0, 1, 2, 4, 8, 16, 24, 32 g N·m^-2·a^-1) on contents of anion and cation in rhizosphere soil, bulk soil, and mixed rhizosphere and bulk soil in the heavily salinized grassland in the agro-pastoral ecotone of North China. The results showed that pH of rhizosphere, mixed and bulk soils decreased significantly with the increases of nitrogen addition levels. Moreover, pH of three soil types under the 32 g N·m^-2·a^-1 treatment decreased by 1.2, 0.9, and 0.6, respectively, while pH of rhizosphere soil decreased by 0.44 compared with the bulk soil. Na⁺ content of rhizosphere, mixed and bulk soils significantly decreased, while the NO₃^- content significantly increased. The proportion of Na⁺ content in total soluble salt content in rhizosphere soil decreased by 14% and that in bulk soil decreased by 12% after the 32 g N·m^-2·a^-1 addition. NO₃^- content increased by 29% in rhizosphere soil and by 26% in bulk soil. There was significant negative correlation between pH and NO₃^- content, and significant positive correlation between pH and Na⁺ content. The total soluble salt content of rhizosphere soil under the 32 g N·m^-2·a^-1 treatment was significantly reduced by 31.5%. Collectedly, nitrogen deposition could reduce soil pH and total soluble salt content of rhizosphere soil and alleviate saline-alkali stress.

Effects of salt stress on bacterial community composition and diversity in rhizosphere soil of Bletilla striata

LI Jing, ZHANG Xiaofei, ZHANG Huiwen, WEN Jiaqing, ZHANG Yan, XU Lingling

2024, 35(1): 219-228. doi:10.13287/j.1001-9332.202401.010

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Salinization environment affects the normal growth and development of plants, as well as the microbial community in the rhizosphere. To explore the succession dynamics of bacterial communities in the rhizosphere soil of Bletilla striata under salt stress condition, we performed 16S rRNA high-throughput sequencing to determine the bacterial community composition and diversity of B. striata in the rhizosphere under different salt stress concentrations, measured the effects of salt stress on the growth and development of B. striata and soil physicochemical pro-perties, and analyzed the correlation between community composition of rhizosphere bacteria and the soil environmental factors. The results showed that compared with the control, salt stress reduced growth rate and health degree of B. striata, and significantly decreased the content of soil organic matter, nitrogen and phosphorus. Under the salt stress treatment, species diversity and evenness of the bacterial communities in the rhizosphere of B. striata showed a trend of first decreasing and then increasing. There were significant differences in the relative abundance and variation trends of the dominant bacterial taxa in the rhizosphere soil of B. striata at the phylum and class levels between the control and the salt stress treatments. Salt stress intensity and duration were important factors affecting bacterial community composition in the rhizosphere soil of B. striata. Soil organic matter, available nitrogen, and total phosphorus content were key environmental factors affecting the structure of rhizosphere bacterial community composition. Functional genes related to cytoskeleton, cell motility, substance metabolism and signal transduction mechanisms may be involved in the adaptation and stress response of bacterial communities to salt stress. This study would provide theoretical basis and reference for the cultivation management of B. striatain saline area.

Comparison on the diversity of antibiotic resistance genes of three rodent species

CHU Pengfei, XING Jie, WANG Shengze, LI Ting, QIAO Zhenglei, YUAN Baodong

2024, 35(1): 229-236. doi:10.13287/j.1001-9332.202401.031

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Antibiotic resistance genes (ARGs) have attracted widespread attention as a new global pollutant, mainly due to the abuse of antibiotics. To investigate the diversity of ARGs in three rodent species, we used metagenomic sequencing analysis to analyze the diversity of antibiotic resistance genes of 17 individuals of Apodemus peninsulae and 17 individuals of Myodes rufocanus collected from Mudanfeng, and nine individuals of Apodemus agrarius collected from Sandaoguan. A total of 19 types and 248 subclasses of ARGs were detected in the three rodent species. Seven ARGs showed significant difference and five ARGs showed extremely significant difference between M. rufocanus and A. agrarius. Seven ARGs showed significant difference and four ARGs showed extremely significant difference between A. peninsulae and A. agrarius. Four ARGs showed significant difference and five ARGs showed extremely significant difference between M. rufocanus and A. peninsulae. ARGs showing high abundance in three rodents were macrolides, lincoamides, tetracyclines, and β-lactams. ARGs were widely distributed in the three rodent species. The significant differences in ARGs among different species might be due to the different distribution areas and their diet differentiation. The study could provide a basis for further studies of ARGs in mice and improve the understanding of the harm of ARGs transmission.

Ecological network optimization of Jiuquan City, Gansu, China based on complex network theory and circuit model

SHI Jing, SHI Peiji, WANG Ziyang, WAN Ya, CHENG Fanyuan, WANG Lirong

2024, 35(1): 237-246. doi:10.13287/j.1001-9332.202401.021

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Building a scientific and reasonable ecological network is the key for optimizing the pattern of territorial development and protection, and is of great significance for ensuring regional ecological security and promoting the virtuous cycle of ecosystems. In previous studies, nodal attack method (destruction of ecological source area) was often used in the “robustness” evaluation of ecological networks. Actually, the ecological corridor is more fragile than the source area, and thus the nodal attack method is not reasonable. In this study, taking Jiuquan City as the research area, based on the circuit model to construct the ecological network, we carried out the topology optimization of ecological network by using three strategies (random edge increase, node degree and priority edge increase with low node intermedium number) in complex network theory. We compared and analyzed the “robustness” of ecological network before and after optimization by constructing edge attack strategy, and selected the best network optimization strategy. The results showed that 65 ecological source areas were identified in Jiuquan City, with a total area of 20275.15 km², and that grassland accounted for 89.5% of the source area. We identified 179 ecological corridors with a total length of 6387.16 km, 158 ecological barrier points with a total area of 1385.5 km². The unused land accounted for 92.2% of the total barrier points area. We identified 63 ecological pinch points, mainly concentrated in the source edge and corridor intersection. Among them, the spatial distribution of 11 barrier points and pinch points was consistent, which was the key area to be repaired in ecological network optimization. The three optimization strategies had significantly improved the stability of ecological network in Jiuquan City. The relative size of the maximum connected subgraph and the edge connected rate of the ecological network of the optimization strategy of adding edges according to degree were all the most stable under random attack mode and deliberate attack mode, which was the best optimization scheme for ecological network in Jiuquan City.

Construction of ecological network with protected areas as the main region in Guangzhou City, China

HUANG Junda, HUANG Jinling, CHEN Chaojin

2024, 35(1): 247-254. doi:10.13287/j.1001-9332.202401.023

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In the context of the national ecological security development strategy, constructing regional ecological networks centered on protected areas and ecological corridors has become an urgent issue in protected areas system development of China. We focused on strengthening ecological connections between protected areas in Guangzhou, identified the ecological resource patches, ecological corridors, and ecological nodes by using Invest model, connectivity analysis, circuit theory models, and graph-theoretical network structure evaluation, and constructed an ecological network for the Guangzhou with nature reserves as the core. The results showed that 52 ecological resource patches were identified in the study area, covering a total area of 1450.01 km². Nature reserves accounted for 76.4% of the total area, forming the main part of the ecological resource patches. 115 ecological corridors were identified, with a total length of 900.56 km and an average length of 7.83 km. Furthermore, 72 ecological key points were identified, covering a total area of 17.57 km², and 81 ecological breakpoints, with a total area of 35.9 km². The network structure indices (α=0.65, β=2.21, and γ=0.77) indicated a reasonably structured and well-connected network. By exploring pathways for constructing regional ecological networks under the protected areas system and enriching the application of circuit theory models in ecological network construction, this study provides scientific basis for regional ecological security and biodiversity conservation.

Optimization of production-living-ecology spatial pattern in Dongting Lake Ecological Economic Zone based on comprehensive benefits of development and protection

WAN Ding, WANG Zhiyuan, TAN Yong, LI Canbin, CHEN Chao, HE Hanhui

2024, 35(1): 255-267. doi:10.13287/j.1001-9332.202401.019

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The optimization of production-living-ecology (PLE) space is an important basis for promoting regional high-quality development. Taking the Dongting Lake Eco-economic Zone as an example, from the perspective of improving the comprehensive benefits of the development and protection of the PLE space, we coupled the GMOP-FLUS model, and proposed an optimization method combining the scenario configuration and the bottom line protection of the PLE space. We compared the three optimization scenarios (economic optimization scenario, ecological optimization scenario, and multi-objective optimization scenario), and coordinated the conflict areas of two lines to clarify the comprehensive optimization scheme of the PLE space in the Dongting Lake Eco-economic Zone. The results showed the characteristics of increasing production space and living space and decreasing ecological space from 2010 to 2020, resulting in the partial loss of land ecological and environmental benefits. Under the economic optimization scenario, the ecological optimization scenario promoted the rapid growth of regional economy but damaged regional ecological security. The ecological optimization scenario inhibited regional economic development. The multi-objective optimization scenario led to improvement of economic and ecological benefits of the PLE space, which increased by 2.0% and 1.3%, respectively. The multi-objective optimization scenario was the best optimization scenario among the three scenarios. By superimposing the best scenario and the two-line conflict regional coordination results, we obtained the comprehensive optimization scheme for 2030. The production space, living space, and ecological space areas of the scheme were 25777.18, 2062.94, and 32552.68 km², respectively. Based on the natural and social conditions, combining the comprehensive optimization scheme, we put forward different control suggestions for each type of PLE space. Our results could provide reference for the rational formulation of territorial spatial planning and the formulation of policies for the coordinated development of ecological environment and social economy in the Dongting Lake Eco-economic Zone.

Develop the rural ecology in the New Era

XUE Bing, LI Hongqing, GANG Shuang, REN Wanxia, WANG Yongsheng, FANG Lan, LI Yongjin, ZHAO Xueyan, CHEN Xin, LI Tianlai

2024, 35(1): 268-274. doi:10.13287/j.1001-9332.202312.033

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Rural ecology is a comprehensive field of study that takes the rural social-ecological-economic systems as the objective object and emphasizes spatial carrier governance. The development of rural ecology in the New Era embodies and implements comprehensively the core concepts of Xi Jinping Thought on Socialism with Chinese Cha-racteristics for a New Era, including harmonious coexistence between humans and nature, rural revitalization, green development, and the comprehensive construction of a socialist modernized nation. Under the goal of Chinese-style modernization, rural ecology exhibits characteristics distinct from the past, such as the integration of research objects, the intersectionality of basic theories, the computational feature of technical methods, and the orientation of exporting outcomes. To provide disciplinary support for modernization-oriented science to meet the new demands of country's rural development, effectively narrating the story of sustainable rural development in China and providing fundamental guarantees for the safety of rural systems, a number of issues such as paradigm innovation in research, improvement of data quality, and integration of comprehensive technologies, should be fully considered.

Research advance on quantitative assessment methods of ecosystem water conservation service functions

LIU Yisheng, HOU Peng, WANG Ping, ZHU Jian

2024, 35(1): 275-288. doi:10.13287/j.1001-9332.202401.022

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The water conservation service function, which is one of the most important ecological service function in the regional system, directly reflects the regulation role of a region in precipitation, the redistribution function of precipitation, and the ecohydrological value. With the development of the comprehensive evaluation method and the deepening of research on water conservation service function, relevant evaluation calculation process has changed significantly. Nowadays, in the assessment of the water conservation service function, it is necessary not only to calculate and evaluate relevant indicators, but also to localize specific parameters in the model and analyze the effectiveness of the overall model for specific study areas. However, the current literature review lacks systematic summaries of model evaluation methods. Meanwhile, the review is also insufficient on model validity verification and significance analysis methods, the result verification and applicability analysis methods such as parameter localization in water conservation studies. We reviewed the research advance on typical ecosystem water conservation ser-vice assessment methods with a specific focus on the model assessment methods that have developed rapidly in recent years. At the same time, we summarized methods commonly used for parameter localization, as well as validity testing and sensitivity analysis of simulation results, and discussed existing problems and future directions in this field.

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