The carbon and water cycle, an important biophysical process of terrestrial ecosystems, may be changed by anthropogenic revegetation in arid and semiarid areas. However, there is still a lack of understanding of the mechanism of carbon and water coupling in intrinsic ecosystems in the context of human activities. Based on the CO2 and H2O flux measurements of the desert steppe with the planted shrub Caragana liouana, this study explores the carbon and water flux coupling of the ecosystem by analyzing the variations in gross primary productivity (GPP), evapotranspiration (ET), and water use efficiency (WUE) and discussing the driving mechanism of biological factors. The seasonal variation in climate factors induced a periodic variation pattern of biophysical traits and carbon and water fluxes. The GPP and ET fluctuated in season, but the WUE was relatively stable in the growing season. The GPP, ET, and WUE were significantly driven by global radiation (Rg), temperature (Ta and Ts), water vapor pressure deficit (VPD), leaf area index (LAI), and plant water stress index (PWSI). However, Rg, temperature, and PWSI were the most important factors regulating WUE. Rg and temperature directly affected WUE with a positive effect but indirectly inhibited WUE by rising PWSI. Plant water stress inhibited photosynthesis and transpiration of the planted shrub community in desert steppe. When the plant water stress breaks a threshold (PWSI >0.54), the WUE will decrease since the GPP respond more quickly to the plant water stress than ET. Our findings suggest that policies related to large-scale carbon sequestration initiatives under afforestation must first fully consider the statuses of water consumption and WUE.
{"title":"Carbon-water coupling and its relationship with environmental and biological factors in a planted Caragana liouana shrub community in desert steppe, northwest China","authors":"Lingfeng Du, Longlong Ma, Hairong Pan, Chenglong Qiao, Chen Meng, Hongyue Wu, Jing Tian, Honggang Yuan","doi":"10.1093/jpe/rtac064","DOIUrl":"https://doi.org/10.1093/jpe/rtac064","url":null,"abstract":"\u0000 The carbon and water cycle, an important biophysical process of terrestrial ecosystems, may be changed by anthropogenic revegetation in arid and semiarid areas. However, there is still a lack of understanding of the mechanism of carbon and water coupling in intrinsic ecosystems in the context of human activities. Based on the CO2 and H2O flux measurements of the desert steppe with the planted shrub Caragana liouana, this study explores the carbon and water flux coupling of the ecosystem by analyzing the variations in gross primary productivity (GPP), evapotranspiration (ET), and water use efficiency (WUE) and discussing the driving mechanism of biological factors. The seasonal variation in climate factors induced a periodic variation pattern of biophysical traits and carbon and water fluxes. The GPP and ET fluctuated in season, but the WUE was relatively stable in the growing season. The GPP, ET, and WUE were significantly driven by global radiation (Rg), temperature (Ta and Ts), water vapor pressure deficit (VPD), leaf area index (LAI), and plant water stress index (PWSI). However, Rg, temperature, and PWSI were the most important factors regulating WUE. Rg and temperature directly affected WUE with a positive effect but indirectly inhibited WUE by rising PWSI. Plant water stress inhibited photosynthesis and transpiration of the planted shrub community in desert steppe. When the plant water stress breaks a threshold (PWSI >0.54), the WUE will decrease since the GPP respond more quickly to the plant water stress than ET. Our findings suggest that policies related to large-scale carbon sequestration initiatives under afforestation must first fully consider the statuses of water consumption and WUE.","PeriodicalId":50085,"journal":{"name":"Journal of Plant Ecology","volume":"1 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61597351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Michael J O’Brien,Elisa P Carbonnell,Christian Schöb
Abstract The Dehesa ecosystem provides important social and economic values across the Iberian Peninsula and assessing the temporal dynamics of this system under climate change is important for the maintenance and conservation of these highly valuable ecosystems. Here we present the baseline data of an observational plot network in the Dehesa that will form the foundation for monitoring long-term dynamics and for experimental manipulations testing the mechanisms driving resilience within the Dehesa. The initial surveys indicate that the forest structure is typical for the Dehesa, which suggests it is an exemplary site for examining temporal dynamics of this ecosystem. We present these initial data to encourage collaborations from international scientists via either direct experimental projects or meta-analyses.
{"title":"Aprisco Field Station: The spatial structure of a new experimental site focused on agroecology","authors":"Michael J O’Brien,Elisa P Carbonnell,Christian Schöb","doi":"10.1093/jpe/rtac061","DOIUrl":"https://doi.org/10.1093/jpe/rtac061","url":null,"abstract":"Abstract The Dehesa ecosystem provides important social and economic values across the Iberian Peninsula and assessing the temporal dynamics of this system under climate change is important for the maintenance and conservation of these highly valuable ecosystems. Here we present the baseline data of an observational plot network in the Dehesa that will form the foundation for monitoring long-term dynamics and for experimental manipulations testing the mechanisms driving resilience within the Dehesa. The initial surveys indicate that the forest structure is typical for the Dehesa, which suggests it is an exemplary site for examining temporal dynamics of this ecosystem. We present these initial data to encourage collaborations from international scientists via either direct experimental projects or meta-analyses.","PeriodicalId":50085,"journal":{"name":"Journal of Plant Ecology","volume":"26 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138516942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract It has been suggested that the importance of network architecture to species diversity and stability should be based on preference networks (comprised of niche differentiations), rather than observational networks, because species abundance may significantly affect interaction frequencies. Considering that resource abundance is usually greater for herbivores than parasites, we hypothesized that the abundance effect is stronger for parasitic than herbivory interactions. To test this hypothesis, we collected 80 quantitative observational networks including 34 herbivorous and 46 parasitic networks from the published literature, and derived preference networks by removing the effects of species abundance. We then determined the network nestedness using both weighted NODF and spectral radius. We also determined species degree distribution, interaction evenness, weighted connectance and robustness for both observational and preference networks. The observational networks (including both herbivory and parasitic networks) were more nested judged by weighted NODF than spectral radius. Preference networks were less nested for parasitic than herbivory networks in terms of both weighted NODF and spectral radius, possibly because removing the abundance effect increased interaction evenness. These trends indicated that the abundance effect on network nestedness was stronger for parasitic than herbivory networks.Weighted connectance and robustness were greater in most preference networks than observational networks, indicating that preference networks may have higher network stability and community persistence compared to observational ones. The data indicate that future network analyses should not only address the structural difference between mutualistic and antagonistic interactions, but also between herbivory and parasitic interactions.
{"title":"The abundance effect on network nestedness is stronger for parasitic than herbivory interactions","authors":"Bin Lan,Xiaoli Hu,Ying Wang,Shucun Sun","doi":"10.1093/jpe/rtac052","DOIUrl":"https://doi.org/10.1093/jpe/rtac052","url":null,"abstract":"Abstract It has been suggested that the importance of network architecture to species diversity and stability should be based on preference networks (comprised of niche differentiations), rather than observational networks, because species abundance may significantly affect interaction frequencies. Considering that resource abundance is usually greater for herbivores than parasites, we hypothesized that the abundance effect is stronger for parasitic than herbivory interactions. To test this hypothesis, we collected 80 quantitative observational networks including 34 herbivorous and 46 parasitic networks from the published literature, and derived preference networks by removing the effects of species abundance. We then determined the network nestedness using both weighted NODF and spectral radius. We also determined species degree distribution, interaction evenness, weighted connectance and robustness for both observational and preference networks. The observational networks (including both herbivory and parasitic networks) were more nested judged by weighted NODF than spectral radius. Preference networks were less nested for parasitic than herbivory networks in terms of both weighted NODF and spectral radius, possibly because removing the abundance effect increased interaction evenness. These trends indicated that the abundance effect on network nestedness was stronger for parasitic than herbivory networks.Weighted connectance and robustness were greater in most preference networks than observational networks, indicating that preference networks may have higher network stability and community persistence compared to observational ones. The data indicate that future network analyses should not only address the structural difference between mutualistic and antagonistic interactions, but also between herbivory and parasitic interactions.","PeriodicalId":50085,"journal":{"name":"Journal of Plant Ecology","volume":"36 8","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138495040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Muneer, Xiaohui Chen, M. Z. Munir, Z. Nisa, M. Saddique, S. Mehmood, D. Su, Chaoyuan Zheng, B. Ji
Hyphae of arbuscular mycorrhizal fungi (AMF) in soil often form complex mycorrhizal networks among roots of same or different plant species for transfer of nutrients from one plant to another. However, the effect of soil nitrogen (N) availability on nutrient transfer between different plant species via common mycorrhizal networks (CMNs) has not been experimentally examined. In order to quantify CMN-mediated nutrient transfer between Leymus chinensis (LC) and Cleistogene squarrosa (CS), two systems, i.e., the CS-LC system (CS and LC were donor and recipient, respectively) and the LC-CS system (LC and CS were donor and recipient, respectively) were established. Stable isotopic 15N was applied to track N transfer between heterospecific seedlings connected by CMNs under three levels of soil N additions: no N addition control (N0), N addition with 7 mg kg -1 (N1) and N addition with 14 mg kg -1 (N2). In the CS-LC system, the highest rate of AMF colonization and hyphal length density (HLD) were found at N1. In contrast, maximum AMF colonization rate and HLD were recorded at N2 in LC-CS system. Consequently, plant biomass was significantly higher under N1 and N2 levels in CS-LC and LC-CS systems, respectively. Moreover, in CS-LC system, 15N transfer rate ranged from 16% to 61%, with maximum transfer rate at N1. For LC-CS system, 15N transfer rate was much lower, with the maximum occurring at N0. These findings suggest that CMNs could potentially regulate N-transfer from a donor to recipient plant depending upon the strength of individual plant carbon sink.
丛枝菌根真菌(AMF)在土壤中的菌丝常常在相同或不同植物的根系之间形成复杂的菌根网络，以实现养分在植物间的传递。然而，土壤氮(N)有效性对不同植物之间通过常见菌根网络(CMNs)进行养分转移的影响尚未得到实验研究。为了定量测定cmn介导的羊草(Leymus chinensis, LC)与方闭基因(Cleistogene squarrosa, CS)之间的营养传递，建立了CS-LC系统(CS和LC分别为供体和受体)和LC-CS系统(LC和CS分别为供体和受体)。应用稳定同位素15N，在不加氮(N0)、加氮7 mg kg -1 (N1)和加氮14 mg kg -1 (N2) 3种土壤施氮水平下，跟踪CMNs连接的异种幼苗间的氮转移。在CS-LC体系中，AMF定殖率和菌丝长度密度(HLD)在N1时最高。在LC-CS体系中，N2时AMF定殖率和HLD最高。因此，在N1和N2水平下，CS-LC和LC-CS系统的植物生物量均显著增加。在CS-LC体系中，15N的传输率在16% ~ 61%之间，在N1时传输率最大。LC-CS体系的15N传输速率较低，最大传输速率出现在N0。这些发现表明，CMNs可能根据单个植物碳汇的强度，潜在地调节n从供体到受体植物的转移。
{"title":"Interplant transfer of nitrogen between C3 and C4 plants through common mycorrhizal networks under different nitrogen availability","authors":"M. Muneer, Xiaohui Chen, M. Z. Munir, Z. Nisa, M. Saddique, S. Mehmood, D. Su, Chaoyuan Zheng, B. Ji","doi":"10.1093/jpe/rtac058","DOIUrl":"https://doi.org/10.1093/jpe/rtac058","url":null,"abstract":"\u0000 Hyphae of arbuscular mycorrhizal fungi (AMF) in soil often form complex mycorrhizal networks among roots of same or different plant species for transfer of nutrients from one plant to another. However, the effect of soil nitrogen (N) availability on nutrient transfer between different plant species via common mycorrhizal networks (CMNs) has not been experimentally examined. In order to quantify CMN-mediated nutrient transfer between Leymus chinensis (LC) and Cleistogene squarrosa (CS), two systems, i.e., the CS-LC system (CS and LC were donor and recipient, respectively) and the LC-CS system (LC and CS were donor and recipient, respectively) were established. Stable isotopic 15N was applied to track N transfer between heterospecific seedlings connected by CMNs under three levels of soil N additions: no N addition control (N0), N addition with 7 mg kg -1 (N1) and N addition with 14 mg kg -1 (N2). In the CS-LC system, the highest rate of AMF colonization and hyphal length density (HLD) were found at N1. In contrast, maximum AMF colonization rate and HLD were recorded at N2 in LC-CS system. Consequently, plant biomass was significantly higher under N1 and N2 levels in CS-LC and LC-CS systems, respectively. Moreover, in CS-LC system, 15N transfer rate ranged from 16% to 61%, with maximum transfer rate at N1. For LC-CS system, 15N transfer rate was much lower, with the maximum occurring at N0. These findings suggest that CMNs could potentially regulate N-transfer from a donor to recipient plant depending upon the strength of individual plant carbon sink.","PeriodicalId":50085,"journal":{"name":"Journal of Plant Ecology","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48346711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jing Zhang, P. Klinkhamer, K. Vrieling, T. M. Bezemer
Soil biotic communities can strongly impact plant performance. So far, most studies on plant-soil-interactions have estimated the effect of the soil microbial community on plant mass after a fixed duration of plant growth. However, these interactions may change over time and several studies have argued that plant-soil interactions are more important for young seedlings than for older plants. In this paper we ask the question: how long-lasting the effect of the soil microbial community on plant growth is. This is important as the growth rate of a plant is not only determined by the growing conditions but also by the size of the plant itself. Therefore, plant with a reduced growth rate early in life, due to negative effects of the soil microbial community, may increase less in biomass for a much longer period even though the relative growth rates do not differ any longer. We examined the plant growth rates at three stages: early growth (0-21 days), mid growth (22 to 42 days) and late growth (43 to 63 days). We performed two growth experiments with Jacobaea vulgaris lasting 49 and 63 days. Plants were grown in sterilized soil or in sterilized soil inoculated with natural dune soil. In a third experiment, we examined the effect of the timing of soil inoculation prior to planting on the (relative-) growth rate of J. vulgaris plants with four different timing treatments. In all experiments, differences in biomass of plants grown in sterilized soil and inoculated soil (live soil) increased throughout the experiment. Interestingly, linear regression models with ln transformed dry weight against time for younger plants and for older plants in sterilized soil and live soil, respectively, showed that the relative growth rate of plants in the sterilized soil was only significantly higher than that of plants in the live soil in the first two to three weeks. After that period there was no longer a negative effect of the live soil on the relative growth rate of plants. In the third experiment, plant biomass decreased with increasing time between inoculation and planting. Overall, our results show that plants of J. vulgaris grew less well in live soil than in sterilized soil. The negative effects of soil inoculation on plant mass appeared to extend over the whole growth period but arise from the negative effects on relative growth rates that occurred in the first weeks after planting when plants have only less than 5% of the mass they obtained after 42 days. Our study highlights the importance of examining relative growth rates rather than final biomass to estimate the effects of soil microbial communities on plants.
{"title":"The negative effects of soil microorganisms on plant growth only extend to the first weeks","authors":"Jing Zhang, P. Klinkhamer, K. Vrieling, T. M. Bezemer","doi":"10.1093/jpe/rtac022","DOIUrl":"https://doi.org/10.1093/jpe/rtac022","url":null,"abstract":"\u0000 \u0000 \u0000 Soil biotic communities can strongly impact plant performance. So far, most studies on plant-soil-interactions have estimated the effect of the soil microbial community on plant mass after a fixed duration of plant growth. However, these interactions may change over time and several studies have argued that plant-soil interactions are more important for young seedlings than for older plants. In this paper we ask the question: how long-lasting the effect of the soil microbial community on plant growth is. This is important as the growth rate of a plant is not only determined by the growing conditions but also by the size of the plant itself. Therefore, plant with a reduced growth rate early in life, due to negative effects of the soil microbial community, may increase less in biomass for a much longer period even though the relative growth rates do not differ any longer.\u0000 \u0000 \u0000 \u0000 We examined the plant growth rates at three stages: early growth (0-21 days), mid growth (22 to 42 days) and late growth (43 to 63 days). We performed two growth experiments with Jacobaea vulgaris lasting 49 and 63 days. Plants were grown in sterilized soil or in sterilized soil inoculated with natural dune soil. In a third experiment, we examined the effect of the timing of soil inoculation prior to planting on the (relative-) growth rate of J. vulgaris plants with four different timing treatments.\u0000 \u0000 \u0000 \u0000 In all experiments, differences in biomass of plants grown in sterilized soil and inoculated soil (live soil) increased throughout the experiment. Interestingly, linear regression models with ln transformed dry weight against time for younger plants and for older plants in sterilized soil and live soil, respectively, showed that the relative growth rate of plants in the sterilized soil was only significantly higher than that of plants in the live soil in the first two to three weeks. After that period there was no longer a negative effect of the live soil on the relative growth rate of plants. In the third experiment, plant biomass decreased with increasing time between inoculation and planting. Overall, our results show that plants of J. vulgaris grew less well in live soil than in sterilized soil. The negative effects of soil inoculation on plant mass appeared to extend over the whole growth period but arise from the negative effects on relative growth rates that occurred in the first weeks after planting when plants have only less than 5% of the mass they obtained after 42 days. Our study highlights the importance of examining relative growth rates rather than final biomass to estimate the effects of soil microbial communities on plants.\u0000","PeriodicalId":50085,"journal":{"name":"Journal of Plant Ecology","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42683125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Guodong Zhang, Guiyao Zhou, Xuhui Zhou, Lingyan Zhou, J. Shao, Ruiqiang Liu, Jing Gao, Yanghui He, Z. Du, Jianwei Tang, M. Delgado‐Baquerizo
Tropical forests are among the most productive and vulnerable ecosystems in the planet. Several global forestation programs are aiming to plant millions of trees in tropical regions in the future decade. Mycorrhizal associations are known to largely influence forest soil carbon (C) stocks. However, to date, little is known on whether and how different tree mycorrhizal types affect soil respiration (Rs) and C stocks in tropical forests. In this study, we used a three-decade tropical common garden experiment, with three arbuscular mycorrhizal (AM) and three ectomycorrhizal (EM) monocultures, to investigate the impacts of tree mycorrhizal type on Rs and soil C stocks. Associating biotic (e.g. root biomass, litter dynamic, soil microbes) and abiotic factors (e.g. microclimate) were also measured. Our results showed that AM stands supported significantly higher Rs and soil C stock, litter turnover rate, and fine root biomass than EM stands. Further statistical analysis displayed that tree mycorrhizal type was the most important factor in regulating Rs and soil C stock compared with other biotic or abiotic factors. Moreover, we found that mycorrhizal type directly and indirectly affected Rs and soil C stocks via fine root biomass and litter dynamic (i.e. litter production, litter standing crop, and litter turnover rate). Our findings highlight important effects of tree mycorrhizal type on forest C cycle, suggesting that planting AM tree species could contribute to promote soil C stock in tropical ecosystems.
{"title":"Effects of tree mycorrhizal type on soil respiration and carbon stock via fine root biomass and litter dynamic in tropical plantations","authors":"Guodong Zhang, Guiyao Zhou, Xuhui Zhou, Lingyan Zhou, J. Shao, Ruiqiang Liu, Jing Gao, Yanghui He, Z. Du, Jianwei Tang, M. Delgado‐Baquerizo","doi":"10.1093/jpe/rtac056","DOIUrl":"https://doi.org/10.1093/jpe/rtac056","url":null,"abstract":"\u0000 Tropical forests are among the most productive and vulnerable ecosystems in the planet. Several global forestation programs are aiming to plant millions of trees in tropical regions in the future decade. Mycorrhizal associations are known to largely influence forest soil carbon (C) stocks. However, to date, little is known on whether and how different tree mycorrhizal types affect soil respiration (Rs) and C stocks in tropical forests. In this study, we used a three-decade tropical common garden experiment, with three arbuscular mycorrhizal (AM) and three ectomycorrhizal (EM) monocultures, to investigate the impacts of tree mycorrhizal type on Rs and soil C stocks. Associating biotic (e.g. root biomass, litter dynamic, soil microbes) and abiotic factors (e.g. microclimate) were also measured. Our results showed that AM stands supported significantly higher Rs and soil C stock, litter turnover rate, and fine root biomass than EM stands. Further statistical analysis displayed that tree mycorrhizal type was the most important factor in regulating Rs and soil C stock compared with other biotic or abiotic factors. Moreover, we found that mycorrhizal type directly and indirectly affected Rs and soil C stocks via fine root biomass and litter dynamic (i.e. litter production, litter standing crop, and litter turnover rate). Our findings highlight important effects of tree mycorrhizal type on forest C cycle, suggesting that planting AM tree species could contribute to promote soil C stock in tropical ecosystems.","PeriodicalId":50085,"journal":{"name":"Journal of Plant Ecology","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42192754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hu Yao, Haijun Peng, B. Hong, Hanwei Ding, Yetang Hong, Yongxuan Zhu, Jie Wang, Cheng Cai
Wetlands store large amounts of carbon stocks and are essential in both global carbon cycling and regional ecosystem services. Understanding the dynamics of wetland carbon exchange is crucial for assessing the carbon budgets and predicting their future evolution. Although many studies have been conducted on the effects of climate change on the ecosystem carbon cycle, little is known regarding carbon emissions from the alpine wetlands in arid northwest China. In this study, we used an automatic chamber system (LI-8100A) to measure ecosystem respiration in the Bayinbuluk alpine wetland in arid northwest China. The ER showed a significant bimodal diurnal variation, with peak values appearing at 16:30 and 23:30 (Beijing time, UTC+8). A clear seasonal pattern in ER was observed, with the highest value (19.38 μmol m -2 s -1) occurring in August and the lowest value (0.11 μmol m -2 s -1) occurring in late December. The annual ER in 2018 was 678 g C m -2 and respiration during the non-growing season accounted for 13% of the annual sum. Nonlinear regression revealed that soil temperature at 5 cm depth and soil water content were the main factors controlling the seasonal variations in ER. The diurnal variation in ER was mainly controlled by air temperature and solar radiation. Higher temperature sensitivity (Q10) occurred under conditions of lower soil temperatures and medium SWC (25%≤SWC≤40%). The present study deepens our understanding of CO2 emissions in alpine wetland ecosystems and help evaluate the carbon budget in alpine wetlands in arid regions.
湿地储存着大量的碳储量，对全球碳循环和区域生态系统服务都至关重要。了解湿地碳交换的动态对于评估碳预算和预测其未来演变至关重要。尽管人们对气候变化对生态系统碳循环的影响进行了许多研究，但对中国西北干旱地区高山湿地的碳排放却知之甚少。在本研究中，我们使用了一个自动室系统（LI-8100A）来测量中国西北干旱地区巴音布鲁克高山湿地的生态系统呼吸。ER表现出显著的双峰日变化，峰值出现在16:30和23:30（北京时间UTC+8）。ER呈明显的季节性变化，最高值（19.38μmol m-2 s-1）出现在8月，最低值（0.11μmol m-2 s-1。2018年的年ER为678g C m-2，非生长季节的呼吸量占全年总量的13%。非线性回归分析表明，5cm深度的土壤温度和土壤含水量是控制ER季节变化的主要因素，ER的日变化主要受气温和太阳辐射的控制。在较低的土壤温度和中等SWC（25%≤SWC≤40%）的条件下，温度敏感性（Q10）较高。本研究加深了我们对高山湿地生态系统中二氧化碳排放的理解，并有助于评估干旱地区高山湿地的碳预算。
{"title":"Seasonal and diurnal variations in ecosystem respiration and environmental controls from an alpine wetland in arid northwest China","authors":"Hu Yao, Haijun Peng, B. Hong, Hanwei Ding, Yetang Hong, Yongxuan Zhu, Jie Wang, Cheng Cai","doi":"10.1093/jpe/rtac050","DOIUrl":"https://doi.org/10.1093/jpe/rtac050","url":null,"abstract":"\u0000 Wetlands store large amounts of carbon stocks and are essential in both global carbon cycling and regional ecosystem services. Understanding the dynamics of wetland carbon exchange is crucial for assessing the carbon budgets and predicting their future evolution. Although many studies have been conducted on the effects of climate change on the ecosystem carbon cycle, little is known regarding carbon emissions from the alpine wetlands in arid northwest China. In this study, we used an automatic chamber system (LI-8100A) to measure ecosystem respiration in the Bayinbuluk alpine wetland in arid northwest China. The ER showed a significant bimodal diurnal variation, with peak values appearing at 16:30 and 23:30 (Beijing time, UTC+8). A clear seasonal pattern in ER was observed, with the highest value (19.38 μmol m -2 s -1) occurring in August and the lowest value (0.11 μmol m -2 s -1) occurring in late December. The annual ER in 2018 was 678 g C m -2 and respiration during the non-growing season accounted for 13% of the annual sum. Nonlinear regression revealed that soil temperature at 5 cm depth and soil water content were the main factors controlling the seasonal variations in ER. The diurnal variation in ER was mainly controlled by air temperature and solar radiation. Higher temperature sensitivity (Q10) occurred under conditions of lower soil temperatures and medium SWC (25%≤SWC≤40%). The present study deepens our understanding of CO2 emissions in alpine wetland ecosystems and help evaluate the carbon budget in alpine wetlands in arid regions.","PeriodicalId":50085,"journal":{"name":"Journal of Plant Ecology","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45944974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Hou, Qiuyue Li, Pu Yan, Li Xu, Mingxu Li, N. He
Measuring plant heights one by one is an important way to explore the height structure of grassland plant communities, and can be used to analyze the universal rules and regional variations of vegetation growth under environmental change. We chose grasslands in three plateaus, namely Tibetan Plateau (TP), Mongolian Plateau (MP) and Loess Plateau (LP), and set up three grassland transects along the precipitation gradients from meadow, steppe to desert. The mean height of grassland vegetation is 30.38 ± 22.44 cm, and the mean height from TP, MP to LP increases significantly. The aggregation of grassland vegetation presents a positive skew distribution (0.91, 3.60), and the community aggregation from TP, MP to LP tends to a normal distribution (0, 3). However, for TP, there is an exponential distribution in community aggregation of meadows, and a uniform distribution in that of desert. The explanatory effect of climate and soil nutrients on the variation of mean height in each region is more than 70%, while the explanatory effect on the community aggregation is the highest at TP, only 29%. From TP, MP to LP, response intensity of mean height to environmental changes increased significantly, and the influence of temperature and precipitation gradually increased, the influence of radiation, wind speed, and nutrients gradually weakened, and the synergy among environmental factors strengthened. Our study shows that normal distribution is a universal rule of grassland height construction, and the synergy of environmental factors varies from region to region.
{"title":"Universal rule and regional variation of vegetation height assembly of typical grasslands in China","authors":"J. Hou, Qiuyue Li, Pu Yan, Li Xu, Mingxu Li, N. He","doi":"10.1093/jpe/rtac048","DOIUrl":"https://doi.org/10.1093/jpe/rtac048","url":null,"abstract":"\u0000 Measuring plant heights one by one is an important way to explore the height structure of grassland plant communities, and can be used to analyze the universal rules and regional variations of vegetation growth under environmental change. We chose grasslands in three plateaus, namely Tibetan Plateau (TP), Mongolian Plateau (MP) and Loess Plateau (LP), and set up three grassland transects along the precipitation gradients from meadow, steppe to desert. The mean height of grassland vegetation is 30.38 ± 22.44 cm, and the mean height from TP, MP to LP increases significantly. The aggregation of grassland vegetation presents a positive skew distribution (0.91, 3.60), and the community aggregation from TP, MP to LP tends to a normal distribution (0, 3). However, for TP, there is an exponential distribution in community aggregation of meadows, and a uniform distribution in that of desert. The explanatory effect of climate and soil nutrients on the variation of mean height in each region is more than 70%, while the explanatory effect on the community aggregation is the highest at TP, only 29%. From TP, MP to LP, response intensity of mean height to environmental changes increased significantly, and the influence of temperature and precipitation gradually increased, the influence of radiation, wind speed, and nutrients gradually weakened, and the synergy among environmental factors strengthened. Our study shows that normal distribution is a universal rule of grassland height construction, and the synergy of environmental factors varies from region to region.","PeriodicalId":50085,"journal":{"name":"Journal of Plant Ecology","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45857783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
When the shoot apical meristem of plants is damaged or removed, fecundity and/or plant growth may suffer (undercompensation), remain unaffected (compensation), or increase (overcompensation). The latter signifies a potential ‘cost’ of apical dominance. Using natural populations of 19 herbaceous angiosperm species with a conspicuously vertical, apically-dominant growth form, we removed (clipped) the shoot apical meristem for replicate plants early in the growing season to test for a potential cost of apical dominance. Clipped and unclipped (control) plants had their near neighbours removed, and were harvested after flowering production had finished but before seed dispersal. Dry mass was measured separately for aboveground body size (shoots), leaves, seeds, and fruits; and number of leaves, fruits, and seeds per plant were counted. We predicted that: (i) our study species (because of their strong apically-dominant growth form) would respond to shoot apical meristem removal with greater branching intensity, and thus overcompensation in terms of fecundity and/or biomass; and (ii) overcompensation is particularly enabled for species that produce smaller but more leaves, and hence with a larger bud bank of axillary meristems available for deployment in branching and/or fruit production. Widely variable compensatory capacities were recorded, and with no significant between-species relationship with leaf size or leafing intensity — thus indicating no generalized potential cost of apical dominance. Overall, the results point to species-specific treatment effects on meristem allocation patterns, and suggest importance for effects involving local variation in resource availability, and between-species variation in phenology, life history traits, and susceptibility to herbivory.
{"title":"No evidence of a generalized potential ‘cost’ of apical dominance for species that have strong apical dominance","authors":"Jenna V Finley, L. Aarssen","doi":"10.1093/jpe/rtac053","DOIUrl":"https://doi.org/10.1093/jpe/rtac053","url":null,"abstract":"\u0000 When the shoot apical meristem of plants is damaged or removed, fecundity and/or plant growth may suffer (undercompensation), remain unaffected (compensation), or increase (overcompensation). The latter signifies a potential ‘cost’ of apical dominance. Using natural populations of 19 herbaceous angiosperm species with a conspicuously vertical, apically-dominant growth form, we removed (clipped) the shoot apical meristem for replicate plants early in the growing season to test for a potential cost of apical dominance. Clipped and unclipped (control) plants had their near neighbours removed, and were harvested after flowering production had finished but before seed dispersal. Dry mass was measured separately for aboveground body size (shoots), leaves, seeds, and fruits; and number of leaves, fruits, and seeds per plant were counted. We predicted that: (i) our study species (because of their strong apically-dominant growth form) would respond to shoot apical meristem removal with greater branching intensity, and thus overcompensation in terms of fecundity and/or biomass; and (ii) overcompensation is particularly enabled for species that produce smaller but more leaves, and hence with a larger bud bank of axillary meristems available for deployment in branching and/or fruit production. Widely variable compensatory capacities were recorded, and with no significant between-species relationship with leaf size or leafing intensity — thus indicating no generalized potential cost of apical dominance. Overall, the results point to species-specific treatment effects on meristem allocation patterns, and suggest importance for effects involving local variation in resource availability, and between-species variation in phenology, life history traits, and susceptibility to herbivory.","PeriodicalId":50085,"journal":{"name":"Journal of Plant Ecology","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48507112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Leaf size varies conspicuously within and among species under different environments. However, it is unclear how leaf size would change with elevation, whether there is a general elevational pattern, and what determines the altitudinal variation of leaf size. We thus aimed to address these questions by focusing on the broad-leaved herbaceous species at high altitudes on the northeastern Qinghai-Tibetan Plateau. We measured the leaf size, leaf length, leaf width and leaf mass per area for 39 broad-leaved herbaceous species inhabited in the open areas along two mountain slopes from 3 200 m to 4 400 m at the Lenglongling and the Daban Mountain, the northeastern Qinghai-Tibetan Plateau. We analyzed the altitudinal patterns in leaf size in relation to leaf inclination and leaf surface features, and applied a leaf energy balance model to discuss the underlying mechanisms. Leaf size decreased significantly at higher altitudes. The altitudinal reduction was mainly attributed to the reduction of leaf length, and differed in different species, and in leaves with different inclination and leaf surface features. A leaf energy balance model with local environmental measurements demonstrated that leaf temperature tracks air temperature more closely in small than in large leaves, and the leaf-size impact is even stronger at higher latitudes. Based on the observational findings, we proposed that the distribution limit for broad-leaved herbaceous species would be at an elevation of about 5 400 m on the Qinghai-Tibetan Plateau.
{"title":"Reduction in leaf size at higher altitudes across 39 broad-leaved herbaceous species on the Northeastern Qinghai-Tibetan Plateau","authors":"Xin Ke, Hui Kang, Yanhong Tang","doi":"10.1093/jpe/rtac051","DOIUrl":"https://doi.org/10.1093/jpe/rtac051","url":null,"abstract":"\u0000 Leaf size varies conspicuously within and among species under different environments. However, it is unclear how leaf size would change with elevation, whether there is a general elevational pattern, and what determines the altitudinal variation of leaf size. We thus aimed to address these questions by focusing on the broad-leaved herbaceous species at high altitudes on the northeastern Qinghai-Tibetan Plateau. We measured the leaf size, leaf length, leaf width and leaf mass per area for 39 broad-leaved herbaceous species inhabited in the open areas along two mountain slopes from 3 200 m to 4 400 m at the Lenglongling and the Daban Mountain, the northeastern Qinghai-Tibetan Plateau. We analyzed the altitudinal patterns in leaf size in relation to leaf inclination and leaf surface features, and applied a leaf energy balance model to discuss the underlying mechanisms. Leaf size decreased significantly at higher altitudes. The altitudinal reduction was mainly attributed to the reduction of leaf length, and differed in different species, and in leaves with different inclination and leaf surface features. A leaf energy balance model with local environmental measurements demonstrated that leaf temperature tracks air temperature more closely in small than in large leaves, and the leaf-size impact is even stronger at higher latitudes. Based on the observational findings, we proposed that the distribution limit for broad-leaved herbaceous species would be at an elevation of about 5 400 m on the Qinghai-Tibetan Plateau.","PeriodicalId":50085,"journal":{"name":"Journal of Plant Ecology","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47690945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：