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SSRN 2023年

作者： Wang, Jilong Yu, Guirui Han, Lang Yao, Yuan Sun, Mingyu Yan, Zhifeng Institute of Surface-Earth System Science School of Earth System Science Tianjin University Tianjin300072 China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing100101 China College of Resources and Environment University of Chinese Academy of Sciences Beijing100049 China

Coastal wetlands are of great importance for global carbon cycle and climate regulation for its strong carbon uptake capacity. However, the magnitudes, spatial patterns, and potential mechanisms for ecosystem carbon exchange of coastal wetlands at national scale remain poorly understood. Herein, we synthesized ecosystem C fluxes and variables from previous studies to explore their spatial patterns, drivers, and mechanisms of C exchange in China’s coastal wetlands. Our results reveal that China's coastal wetlands absorb 1.38 TgC yr-1, exhibiting a large net CO2 uptake with GPP (gross primary production), NEP (net ecosystem production), and ER (ecosystem respiration) values of 1451 ± 442, 413 ± 240, and 991 ± 297 gC m-2 yr-1, respectively. Significant spatial variations in GPP, NEP, and ER across the coastal wetlands were found, with the highest values in the tropics, followed by subtropics and temperate. Generally, the spatial patterns of carbon exchange exhibited decreasing trend with elevated latitude. With the increase in latitude for each 1°, GPP, NEP and ER decreased by 61.12, 29.19 and 27.14 gC m-2 yr-1, respectively. Meteorological factors including MAT and MAP were the dominating factors for the spatial patterns of ecosystem carbon exchange with respective explanatory power of 31~75% and 36~73%. Moreover, the botanic factors including LAI (leaf area index), FVC (fractional vegetation coverage), and BIOM (biomass) could shift the physiological processes, and thus control the spatial patterns of carbon exchange. The SOC (soil organic carbon) acts as both indicator and factor for the C dynamics. Meanwhile, we found the external disturbances of coastal wetlands could exert more influence on ER than GPP, leading to different responses of GPP and ER to environmental drivers. Our findings highlight the strong carbon uptake capacity and significant spatial variabilities of C exchange in China's coastal wetlands, which were controlled by multifaceted factors and compl

关键词： ecosystems

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Soil Moisture Drives the Spatiotemporal Patterns of Asymmetry in Vegetation Productivity Responses to Dry and Wet Years Across China

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SSRN 2022年

作者： Chang, Qingqing He, Honglin Ren, Xiaoli Zhang, Li Feng, Lili Lv, Yan Zhang, Mengyu Xu, Qian Liu, Weihua Zhang, Yonghong Wang, Tianxiang Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing100101 China National Ecological Science Data Center Beijing100101 China University of Chinese Academy of Sciences Beijing100049 China College of Resources and Environment University of Chinese Academy of Sciences Beijing100049 China State Key Laboratory of Grassland Agro-ecosystems School of Ecology Lanzhou University Gansu Lanzhou730000 China

Increasingly drastic global change is expected to cause hydroclimatic changes, which will influence vegetation productivity and pose a threat to the terrestrial carbon sink. Asymmetry represents an imbalance between vegetation growth and loss of growth during dry and wet periods, respectively. However, the mechanisms of asymmetric plant responses to hydrological changes remain poorly understood. Here, we examined the spatiotemporal patterns of asymmetric responses of vegetation productivity across terrestrial ecosystems in China. We analyzed several observational and satellite-based datasets of plant productivity and several reanalyzed datasets of hydroclimatic variables from 2001 to 2020, and used a random forest model to assess the importance of hydroclimatic variables for these responses. Our results showed that the productivity of >50% of China’s vegetated areas showed a more positive asymmetry (2.3 ± 9.4%) over the study period, which were distributed broadly in northwest China (mainly grasslands and sparse vegetation ecosystems). Negative asymmetries were most common in forest ecosystems in northeast China. We demonstrated that one-third of vegetated areas tended to exhibit significant changes in asymmetry during 2001–2020. The trend towards stronger positive asymmetry (0.95% yr-1) was higher than that towards stronger negative asymmetry (-0.55% yr-1), which is beneficial for the carbon sink. We further showed that in China, soil moisture was a more important driver of spatiotemporal changes on asymmetric productivity than precipitation. We identified thresholds of surface soil moisture (20–30%) and root-zone soil moisture (200–350 mm) that were associated with changes in asymmetry. Our findings highlight the necessity of considering the dynamic responses of vegetation to hydrological factors in order to fully understand the physiological growth processes of plants and avoid the possible loss of productivity due to future climate change. © 2022, The Authors. A

关键词： Productivity

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Changes in Soil Nutrient Stoichiometric Ratios Reveal Increasing Phosphorus Limitation Along a Tropical Soil Chronosequence

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SSRN 2022年

作者： Zhao, Wen Huang, Lai-Ming Yellow River Delta Modern Agricultural Engineering Laboratory Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing100101 China College of Resources and Environment University of Chinese Academy of Sciences Beijing100049 China Key Laboratory of Ecosystem Network Observation and Modeling China

Understanding the variations and controls of stoichiometric ratios of soil nutrients during different stages of soil evolution can provide guidance for ecosystem nutrient management and regulation. This study investigated the changes in and factors associated with soil nutrient stoichiometric ratios during different stages of soil development using a well-established soil chronosequence (0.09, 0.146, 0.64, 1.12, 1.81, and 2.30 million years) developed on basalt in southern China. Results showed that available nitrogen (AN) decreased continuously with increasing soil age. Total nitrogen (TN), total phosphorus (TP), available phosphorus (AP), and soil organic carbon (SOC) increased initially during the early stage of soil development, reaching peak values in the 0.146 million-year-old soil profiles. Thereafter, TP and AP fluctuated with increasing soil age, whereas SOC exhibited a decreasing trend with aging soil. The profile-averaged C:N (9.82–12.75), C:P (0.86–1.98), and N:P (0.86–1.98) remained relatively stable across the soil chronosequence (the coefficient of variation (CV) 0.64 million years) developed on basalt to alleviate the increasing P limitation in the late stage of soil evolution. © 2022, The Authors. All rights reserved.

关键词： Soils

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A review of mass flux monitoring and estimation methods for biogeochemical interface processes in watersheds

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Journal of Geographical Sciences 2020年第6期30卷 881-907页

作者： LU Yao GAO Yang YANG Tiantian Key Laboratory of Ecosystem Network Observation and Modeling.Institute of Geographic Sciences and Natural Resources Research CASBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China School of Clvil Engineering and Environmental Science University of Oklahoma.NormanOK 73019.United States

The magnitude of mass flux is closely associated with biogeochemical watershed processes,which can generate a considerable amount of pertinent ***,both the accuracy and precision of mass flux estimation results directly affects the perception of the ecological environmental status,which in turn affects both the formulation and implementation of river basin management *** practical applications,the true value of flux is unknown and can only be *** results obtained using different monitoring and estimation methods also differ ***,in existing studies on mass flux associated with biogeochemical watershed interfaces,the application of monitoring and estimation methods lacks uniform criteria or ***,this study summarizes and deconstructs results from recent studies on biogeochemical watershed interface processes and compares the advantages,disadvantages and applicability of the monitoring and estimation methods used by these *** particular study is intended to be used as a reference for the selection of flux calculation methods.

关键词： flux basin monitoring estimation biogeochemical cycle

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Fungal Necromass Contribute More to Organic Carbon Sequestration than Bacterial Necromass in Tobacco-Planted Field

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SSRN 2023年

作者： Tang, Zuoxin Feng, Junna Chen, Lulu Chen, Zebin Shao, Xiaodong Xia, Tiyuan College of Agricultural and Life Sciences Kunming University Yunnan Kunming650214 China Key Laboratory of Ecosystem Network Observation and Modeling Center for Forest Ecosystem Studies and Qianyanzhou Ecological Station Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing100101 China Honghe Branch of Yunnan Tobacco Company Mile Yunnan652300 China

Microbial necromass carbon (MNC) is an important component of soil organic carbon (SOC). Although the contribution of MNC to stable SOC pool has been recognized, the response of MNC to fertilization in flue-cured tobacco growing soils is rarely studied. In this study, microbial biomarkers were extracted from rhizosphere soil and used to measure the relationship between the soil microbial community composition (using phospholipid fatty acids, PLFAs) and MNC (using amino sugars), and the contribution of MNC to SOC and its fractions (including particulate and mineral-associated organic carbon (POC and MAOC)) under compound and microbial fertilizer addition. The results showed that the accumulation of amino sugars and MNC increased with the growth period and was affected by the limitation of microbial resources. Compared with other treatments, compound fertilizer reduction combined with microbial fertilizer treatment increased the content of amino sugars and MNC, especially during the harvest period. The contribution of MNC to SOC varied from 38.03% to 50.49%, while the contribution of fungal necromass carbon (FNC) to SOC, POC, and MAOC was approximately three times that of bacterial necromass car-bon (BNC). The content of MNC and FNC increased significantly with the increase of POC, and POC accumulation rate is greater than MAOC. By forming POC, the contribution of fungal necro-mass carbon to SOC was promoted. While the relationship between MAOC and BNC was closer than that of FNC. Hence, bacterial necromass carbon was involved in SOC turnover while fungal necromass carbon dominantly contribute to SOC accumulation. In addition, microbial biomass and microbial community structure composition are important determinants of amino sugars and MNC. Summarizing, these results provided a new idea for the microbial mechanism of controlling carbon persistence in tobacco planting soil, and the POC and MAOC components, and microbial fertilizer partially replace compound fertilizer

关键词： Organic carbon

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Relationship of minimum winter temperature and temperature seasonality to the northern range limit and species richness of trees in North America

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Journal of Geographical Sciences 2022年第2期32卷 280-290页

作者： Hong QIAN ZHANG Yangjian Robert E.RICKLEFS Xianli WANG Research and Collections Center Illinois State Museum1011 East Ash StreetSpringfieldIL 62703USA Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China Department of Biology University of Missouri–St.LouisSt.LouisMO 63121USA Northern Forestry Centre Canadian Forest ServiceNatural Resources Canada5320-122nd StreetEdmontonAB T6H 3S5Canada Department of Renewable Resources University of Alberta751 General Service Building EdmontonAB T6G 2H1Canada

Biologists have considered both winter coldness and temperature seasonality as major determinants of the northern limits of plants and animals in the Northern Hemisphere,which in turn drive the well-known latitudinal diversity ***,few studies have tested which of the two climate variables is the primary *** this study,we assess whether winter coldness or temperature seasonality is more strongly associated with the northern latitudinal limits of tree species and with tree species richness in North *** species were recorded in each of 1198 quadrats of 110 km×110 km in North *** used correlation and regression analyses to assess the relationship of the latitude of the northern boundary of each species,and of species richness per quadrat,with winter coldness and temperature *** richness was analyzed within 38 longitudinal,i.e.,north-south,bands(each being>1100 km long and 110 km wide).The latitudes of the northern range limits of tree species were three times better correlated with minimum temperatures at those latitudes than with temperature *** average,minimum temperature and temperature seasonality together explained 81.5%of the variation in the northern range limits of the tree species examined,and minimum temperature uniquely explained six-fold(33.7%versus 5.8%)more of this variation than did temperature *** of tree species richness with minimum temperatures were stronger than correlations with temperature seasonality for most of the longitudinal bands *** to temperature seasonality,winter coldness is more strongly associated with species distributions at high latitudes,and is likely a more important driver of the latitudinal diversity gradient.

关键词： cold tolerance latitudinal diversity gradient minimum temperature temperature seasonality temperature variation trees tropical conservatism hypothesis

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Variability in evapotranspiration shifts from meteorological to biological control under wet versus drought conditions in an alpine meadow

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Journal of Plant Ecology 2022年第5期15卷 921-932页

作者： Mingjie Xu Tingting An Zhoutao Zheng Tao Zhang Yangjian Zhang Guirui Yu College of Agronomy Shenyang Agricultural UniversityShenyang 110866China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 10010lChina Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of SciencesBeijing 10010lChina College of Resources and Environment University of Chinese Academy of SciencesBeijing 100190China

The Tibetan Plateau is generally referred to as the Chinese water tower,and evapotranspiration(ET)affects the water budget and stability of alpine meadows on the Tibetan ***,its variability and controlling mechanisms have not been well documented under the drier conditions induced by global ***,this study aimed to clarify whether meteorological or biological factors primarily affected the variability in ET under contrasting water conditions in the alpine meadow ecosystem on the Tibetan *** on 6-year(2013-2018)eddy covariance observations and the corresponding meteorological and biological data,linear perturbation analyses were employed to isolate the contributions of meteorological and biological factors to the variability in evapotranspiration(SET).The results showed that ET was mainly driven by meteorological factors in wet peak seasons(July and August),and was dominated by net radiation(Rn)and air temperature(Ta),indicating that the inadequate available energy is the factor limiting ***,the dominant factors affecting SET shifted from meteorological to biological in dry peak seasons when the canopy stomatal conductance(gs)and leaf area index were *** this point,the ecosystem was limited by the water *** results provide empirical insights into how meteorological and biological factors regulate variability in ET under contrasting water *** findings can further improve our understanding of water cycle processes and can help effectively manage water resources in alpine meadow ecosystems under future climate change conditions.

关键词： ET climate effects biotic effects eddy covariance Tibetan Plateau

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Nitrogen additions inhibit nitrification in acidic soils in a subtropical pine plantation: effects of soil pH and compositional shifts in microbial groups

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Journal of Forestry Research 2019年第2期30卷 669-678页

作者： Liang Kou Xinyu Zhang Huimin Wang Hao Yang Wei Zhao Shenggong Li Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences University of Chinese Academy of Sciences Jiangxi Provincial Key Laboratory of Ecosystem Processes and Information

Plantation forests play a pivotal role in carbon sequestration in terrestrial ecosystems, but enhanced nitrogen(N) deposition in these forests may affect plantation productivity by altering soil N cycling. Hence,understanding how simulated N deposition affects the rate and direction of soil N transformation is critically important in predicting responses of plantation productivity in the context of N loading. This study reports the effects of N addition rate(0, 40, and 120 kg N ha^(-1) a^(-1)) and form(NH_4Cl vs. NaNO_3) on net N mineralization and nitrification estimated by in situ soil core incubation and on-soil microbial biomass determined by the phospholipid fatty acid(PLFA) method in a subtropical pine plantation. N additions had no influences on net N mineralization throughout the year. Net nitrification rate was significantly reduced by additions of both NH_4Cl(71.5) and NaNO_3(47.1%) during the active growing season, with the stronger inhibitory effect at high N rates. Soil pH was markedly decreased by 0.16 units by NH_4Cl additions. N inputs significantly decreased the ratio of fungal-to-bacterial PLFAs on average by 0.28(49.1%) in November. Under NH_4Cl additions, nitrification was positively related with fungal biomass and soil pH. Under NaNO_3 additions,nitrification was positively related with all microbial groups except for bacterial biomass. We conclude that simulated N deposition inhibited net nitrification in the acidic soils of a subtropical plantation forest in China,primarily due to accelerated soil acidification and compositional shifts in microbial functional groups. These findings may facilitate a better mechanistic understanding of soil N cycling in the context of N loading.

关键词： Acidification Atmospheric nitrogen deposition Microbial functional group Nitrification Soil nitrogen transformation

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Progress in watershed geography in the Yangtze River Basin and the affiliated ecological security perspective in the past 20 years,China

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Journal of Geographical Sciences 2020年第6期30卷 867-880页

作者： GAO Yang JIA Junjie LU Yao SUN Xiaomin WEN Xuefa HE Nianpeng YANG Tiantian Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China College of Resources and Environment University of Chinese Academy of Sciences.Beijing 100049China School of Civil Engineering and Environmental Science.University of Oklahoma NormanOK 73019United States

Bibliometrics was used to statistically analyze key zones within the Yangtze River Basin(YRB)funded by the National Natural Science Foundation of China(NSFC)and national ministries over the past 20 *** study determined that funds that derived from national ministries have mainly focused on issues related to environmental pollution,ecological security,technological water regulations,and river basin ecosystems,which offer a better understanding of the national requirements and the scientific knowledge of the YRB in combination with data from the *** a background of bolstering the construction of green ecological corridors in the economic belt of the YRB,this study proposes future conceptual watershed research initiatives in this region as a study objective by reinforcing the implementation of the Chinese Ecosystem Research network(CERN)and by emphasizing the use of new technologies,new methods,and new concepts for the prospective design of frontier research under the perspective of geoscience and earth system *** study promotes large-scale scientific field and research objectives based on big science and big data.

关键词： watershed physiography ecological security earth system science critical zone C-N-H20 coupling Yangtze River Basin

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Fisher discriminant analysis method applied in drought detection:an instance in an alpine meadow ecosystem

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Journal of Plant Ecology 2022年第5期15卷 911-920页

作者： Tao Zhang Ximeng Ji Yuanyuan Tang Mingjie Xu Yangjian Zhang Guang Zhao Ning Chen Juntao Zhu Yongtao He College of Agronomy Shenyang Agricultural UniversityShenyang 110866China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 1oo1olChina Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 10o049China Key Laboratory of Wetland Ecology and Environment Northeast Institute of Geography and AgroecologyChinese Academy of SciencesChangchun 130102China

Fisher discriminant analysis can comprehensively take multiple factors into consideration and effectively conduct separations between two *** it can be used to detect the occurrences of drought,drought can be detected more effectively and *** on 9-year carbon flux and corresponding meteorological data,soil water content(SWC)and vapor pressure deficit(VPD)were selected as the discriminant *** occurrences were detected by applying the Fisher discriminant analysis method in an alpine ecosystem in *** discriminant analysis was successfully applied to detect drought occurrence in an alpine meadow *** soil water deficit and atmospheric water deficit were comprehensively taken into ***,this method could detect the onset and end date of droughts more accurately and *** on the characteristics of drought and non-drought samples,the discriminant equation was constructed as y=*** y>1,the days were distributed above the critical *** addition,when y was greater than one for more than 10 days,it was labeled as one drought *** the interval between two drought processes was less than 2 days,it was considered one drought *** increasing the study period and continued accumulation of observation data,the discriminant equation could be further optimized in the future,resulting in more accurate drought detection.

关键词： soil water VPD GPP alpine meadow Tibetan Plateau

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