The theory of ecology is based on over 100 a of research and investigation, all centered on aboveground pat-terns and processes. However, as contemporary ecologists are increasingly acknowledging, belowground structur...The theory of ecology is based on over 100 a of research and investigation, all centered on aboveground pat-terns and processes. However, as contemporary ecologists are increasingly acknowledging, belowground structures, func-tions, and processes are some of the most poorly understood areas in ecology. This lack of understanding of belowground ecological processes seriously restricts the advance of global change research. The interdisciplinary field of belowground ecology began to flourish in the 1990s, along with the expan-sion of global change research, and quickly gained momen-tum. Belowground ecology aims to investigate belowground structures, functions, and processes, as well as their rela-tionships with corresponding aboveground features, empha-sizing the responses of belowground systems under global change conditions. Key research areas include root ecology, belowground animals, and soil microorganisms. This review summarizes and analyzes the relationships between above- and belowground ecosystems, root ecology, root biogeogra-phy, belowground biodiversity, as well as research areas with particular challenges and progress. This commentary em-phasizes certain theoretical issues concerning the responses of belowground processes to global change, and concludes that belowground ecology is a critical research priority in the 21st century.展开更多
氮沉降的增加显著改变了生态系统功能和过程。大量研究表明,氮添加会提高生态系统生产力,然而,大部分研究集中在地上生物量,对地下生物量以及根冠比的研究较少。我们在内蒙古典型草原进行了7年的氮添加实验,设置6个氮添加水平,分别是N0...氮沉降的增加显著改变了生态系统功能和过程。大量研究表明,氮添加会提高生态系统生产力,然而,大部分研究集中在地上生物量,对地下生物量以及根冠比的研究较少。我们在内蒙古典型草原进行了7年的氮添加实验,设置6个氮添加水平,分别是N0(0)、N1(5.6 g N·m^-2)、N2(11.2 g N·m^-2)、N3(22.4 g N·m^-2)、N4(39.2 g N·m^-2)、N5(56 g N·m^-2),测定植物地上和不同土层(0~10、10~30、30~50和50~100 cm)地下生物量并计算根冠比,研究不同氮添加水平对植物地上、地下生物量和根冠比的影响。结果表明:(1)与对照相比,低氮添加水平(N1和N2)未显著增加地上生物量,高氮添加水平(N3~N5)显著增加了地上生物量(96%~117%),且各高氮添加水平间差异不显著;(2)不同氮添加水平下,植物地上生物量的氮响应效率(NRE)均大于0且呈下降趋势,相邻氮添加水平的NRE差值(ΔNRE)仅在N3水平下显著增加,说明地上生物量在N3水平下达到饱和;(3)氮添加未显著改变不同土层以及整个土壤剖面上的地下生物量,且对各土层地下生物量的占比情况无显著影响;(4)与对照相比,N1和N2未显著改变植物的根冠比,N3~N5显著降低了植物根冠比。综上所述,氮沉降增加会提高植物地上生物量,对不同土层根系的影响比较复杂,需要更多的研究来明确地下生产力对氮沉降增加的响应规律。展开更多
Land use changes affect belowground ecosystems.During the past few decades,land use in Northeast China has changed considerably,and the area of paddy fields has increased rapidly from upland.In this study,soil charact...Land use changes affect belowground ecosystems.During the past few decades,land use in Northeast China has changed considerably,and the area of paddy fields has increased rapidly from upland.In this study,soil characteristics and soil biotic community in paddy fields with different years of rice cultivation were measured to examine the effects of land use change from upland to paddy fields on soil micro-food web.The upland maize fields were selected as control and the microbial community composition was characterized using phospholipid fatty acids(PLFAs) analysis.The microbial biomass(total PLFA),bacteria biomass,and fungi biomass were higher in the 20-40-year(late-stage) than 1-10-year(early-stage) paddy fields.The abundances of total nematodes and bacterivores were lower in the early-stage than late-stage paddy fields.The abundance of herbivores was the highest in the early-stage paddy fields but that of omnivore-predators was the highest in the late-stage paddy fields.Structural equation model indicated that soil food web was developed and structured after 20 years of paddy cultivation.Our results suggested that soil micro-food web may be a good indicator for soil development and stabilization of paddy fields following land use change.展开更多
在美国俄勒冈州,控制西美圆柏(Juniperus occidentalis)的数量是一种公认的牧场管理措施,该做法有助于恢复蒿草草原(sagebrush steppe)生境,该生境对野生动物和家畜都十分重要。然而,尽管控制木本植物数量会对当地的流域管理和区域性氮...在美国俄勒冈州,控制西美圆柏(Juniperus occidentalis)的数量是一种公认的牧场管理措施,该做法有助于恢复蒿草草原(sagebrush steppe)生境,该生境对野生动物和家畜都十分重要。然而,尽管控制木本植物数量会对当地的流域管理和区域性氮库造成重要影响,但砍伐西美圆柏对生态系统中氮元素的影响问题尚未得到很好的解决。本文定量研究了两个相邻流域生态系统中的氮储量,其中一个流域经过处理(流域内的大部分圆柏已被清除掉),而另一个流域未处理(圆柏未被清除)。在圆柏被移除13年后,我们测定了两个流域里圆柏树林、灌木丛、草丛和枯枝落叶层的地上氮储量,以及两个流域中两个土层(0–25和25–50 cm)内的地下氮储量(根系和土壤氮储量)。研究结果表明,未处理流域的地上氮储量是处理流域的6.9倍,因为未处理流域的地上生物量要大得多。然而,由于砍伐圆柏导致林下植被的根系生物量增加,所以处理流域的根系氮储量是未处理流域的3.1倍。0–25和25–50 cm土层氮储量没有受到圆柏砍伐的影响。总体而言,生态系统总氮储量在处理流域(9536 kg N ha−1)和未处理流域(9456 kg N ha−1)之间并没有显著差异。在两个流域里,生态系统中最大的氮积累量(至少95%的生态系统总氮量)均存在于地下(0–25 cm深的土壤以及根系)。这项研究证明,清除圆柏并不会显著影响生态系统的储氮能力。展开更多
基金We gratefully acknowledge the support of the National Natural Science Foundation of China(32171592,32061123005,and 31270476)in funding this researchThis work in the design of the study and collection of data was supported by the National Natural Science Foundation of China。
文摘The theory of ecology is based on over 100 a of research and investigation, all centered on aboveground pat-terns and processes. However, as contemporary ecologists are increasingly acknowledging, belowground structures, func-tions, and processes are some of the most poorly understood areas in ecology. This lack of understanding of belowground ecological processes seriously restricts the advance of global change research. The interdisciplinary field of belowground ecology began to flourish in the 1990s, along with the expan-sion of global change research, and quickly gained momen-tum. Belowground ecology aims to investigate belowground structures, functions, and processes, as well as their rela-tionships with corresponding aboveground features, empha-sizing the responses of belowground systems under global change conditions. Key research areas include root ecology, belowground animals, and soil microorganisms. This review summarizes and analyzes the relationships between above- and belowground ecosystems, root ecology, root biogeogra-phy, belowground biodiversity, as well as research areas with particular challenges and progress. This commentary em-phasizes certain theoretical issues concerning the responses of belowground processes to global change, and concludes that belowground ecology is a critical research priority in the 21st century.
文摘氮沉降的增加显著改变了生态系统功能和过程。大量研究表明,氮添加会提高生态系统生产力,然而,大部分研究集中在地上生物量,对地下生物量以及根冠比的研究较少。我们在内蒙古典型草原进行了7年的氮添加实验,设置6个氮添加水平,分别是N0(0)、N1(5.6 g N·m^-2)、N2(11.2 g N·m^-2)、N3(22.4 g N·m^-2)、N4(39.2 g N·m^-2)、N5(56 g N·m^-2),测定植物地上和不同土层(0~10、10~30、30~50和50~100 cm)地下生物量并计算根冠比,研究不同氮添加水平对植物地上、地下生物量和根冠比的影响。结果表明:(1)与对照相比,低氮添加水平(N1和N2)未显著增加地上生物量,高氮添加水平(N3~N5)显著增加了地上生物量(96%~117%),且各高氮添加水平间差异不显著;(2)不同氮添加水平下,植物地上生物量的氮响应效率(NRE)均大于0且呈下降趋势,相邻氮添加水平的NRE差值(ΔNRE)仅在N3水平下显著增加,说明地上生物量在N3水平下达到饱和;(3)氮添加未显著改变不同土层以及整个土壤剖面上的地下生物量,且对各土层地下生物量的占比情况无显著影响;(4)与对照相比,N1和N2未显著改变植物的根冠比,N3~N5显著降低了植物根冠比。综上所述,氮沉降增加会提高植物地上生物量,对不同土层根系的影响比较复杂,需要更多的研究来明确地下生产力对氮沉降增加的响应规律。
基金supported by the National Key Research & Development(R&D) Plan of China(No. 2016YFD0300204)the National Basic Research Program(973 Program) of China(No.2011CB100504)
文摘Land use changes affect belowground ecosystems.During the past few decades,land use in Northeast China has changed considerably,and the area of paddy fields has increased rapidly from upland.In this study,soil characteristics and soil biotic community in paddy fields with different years of rice cultivation were measured to examine the effects of land use change from upland to paddy fields on soil micro-food web.The upland maize fields were selected as control and the microbial community composition was characterized using phospholipid fatty acids(PLFAs) analysis.The microbial biomass(total PLFA),bacteria biomass,and fungi biomass were higher in the 20-40-year(late-stage) than 1-10-year(early-stage) paddy fields.The abundances of total nematodes and bacterivores were lower in the early-stage than late-stage paddy fields.The abundance of herbivores was the highest in the early-stage paddy fields but that of omnivore-predators was the highest in the late-stage paddy fields.Structural equation model indicated that soil food web was developed and structured after 20 years of paddy cultivation.Our results suggested that soil micro-food web may be a good indicator for soil development and stabilization of paddy fields following land use change.
基金This research was supported by Oregon State University and the Oregon Agricultural Experiment Station。
文摘在美国俄勒冈州,控制西美圆柏(Juniperus occidentalis)的数量是一种公认的牧场管理措施,该做法有助于恢复蒿草草原(sagebrush steppe)生境,该生境对野生动物和家畜都十分重要。然而,尽管控制木本植物数量会对当地的流域管理和区域性氮库造成重要影响,但砍伐西美圆柏对生态系统中氮元素的影响问题尚未得到很好的解决。本文定量研究了两个相邻流域生态系统中的氮储量,其中一个流域经过处理(流域内的大部分圆柏已被清除掉),而另一个流域未处理(圆柏未被清除)。在圆柏被移除13年后,我们测定了两个流域里圆柏树林、灌木丛、草丛和枯枝落叶层的地上氮储量,以及两个流域中两个土层(0–25和25–50 cm)内的地下氮储量(根系和土壤氮储量)。研究结果表明,未处理流域的地上氮储量是处理流域的6.9倍,因为未处理流域的地上生物量要大得多。然而,由于砍伐圆柏导致林下植被的根系生物量增加,所以处理流域的根系氮储量是未处理流域的3.1倍。0–25和25–50 cm土层氮储量没有受到圆柏砍伐的影响。总体而言,生态系统总氮储量在处理流域(9536 kg N ha−1)和未处理流域(9456 kg N ha−1)之间并没有显著差异。在两个流域里,生态系统中最大的氮积累量(至少95%的生态系统总氮量)均存在于地下(0–25 cm深的土壤以及根系)。这项研究证明,清除圆柏并不会显著影响生态系统的储氮能力。
