,, 许士麒,, 孙新超,, 刘学炎,
,*天津大学表层地球系统科学研究院, 天津 300072Effects of exotic plant invasion on soil nitrogen availability
XU Hao, HU Chao-Chen,, XU Shi-Qi,, SUN Xin-Chao,, LIU Xue-Yan,,*Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China通讯作者:
收稿日期:2018-09-11接受日期:2018-10-18网络出版日期:2018-11-20
| 基金资助: |
Received:2018-09-11Accepted:2018-10-18Online:2018-11-20
| Fund supported: |
摘要
关键词：
Abstract
Methods Based on differences in soil N contents between invaded and uninvaded areas in natural ecosystems at the same study sites, this study explored magnitudes and ecophysiological mechanisms of soil N variations under exotic plant invasion.
Important findings Based on the data integrated from 107 papers, we found that contents of soil total N, ammonium-N, nitrate-N, inorganic N, microbial biomass N under exotic plant invasion were increased by (50 ± 14)%, (60 ± 24)%, (470 ± 115)%, (69 ± 25)%, (54 ± 20)% respectively relative to those under no invasion. The increment in the soil nitrate-N pool was highest, suggesting higher nitrification rate, which potentially promoted plant nitrate-N utilization and the coexistence of nitrate-preferring species. The increment of soil nitrate-N pool under invasion was higher in the temperate zone than the subtropical zones significantly. Invasion of N2-fixing plants caused obviously larger increments of soil total N and nitrate-N contents compared to invasion of non-N2-fixing plants. The invasion of woody and evergreen invasive plants caused larger increments of soil total N than herbaceous and deciduous plants, respectively. The increases in soil ammonium-N under invasion did not differ substantially among different life forms and showed no clear relationship with the percentage of N2-fixing plants. Differently, soil nitrate-N showed much larger increments under invasion and showed positive linear relationship with the percentage of N2-fixing invasive plants. The N2-fixing function, litter quality and quantity of invasive plants are important factors regulating soil N mineralization and nitrification under invasion. This study provides novel insights into the mechanisms underlying the success and aggravation of plant invasion and into the relationships between soil N dynamics and plant functional traits in ecosystems under exotic plant invasion.
Keywords：
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许浩, 胡朝臣, 许士麒, 孙新超, 刘学炎. 外来植物入侵对土壤氮有效性的影响. 植物生态学报[J], 2018, 42(11): 1120-1130 doi:10.17521/cjpe.2018.0219
XU Hao, HU Chao-Chen, XU Shi-Qi, SUN Xin-Chao, LIU Xue-Yan.
外来植物入侵指在人为或自然因素作用下, 植物由原产地进入新栖息地存活、繁殖、建群、扩张, 并造成明显的生态或经济影响的现象(Theoharides & Dukes, 2007; Zheng et al., 2018)。植物入侵减少生物多样性, 破坏生态系统结构和功能, 威胁农、林、牧业发展, 造成巨大经济损失, 现已成为较严重的生态环境问题(Pimentel et al., 2005; Ding et al., 2008; 类延宝等, 2010; 李博和马克平, 2010; 闫小玲等, 2012)。
由于氮是植物生存生长重要的限制性资源, 因此入侵植物如何影响土壤氮有效性是理解其入侵机制的重要研究内容(Ehrenfeld, 2003; Sardans et al., 2016)。入侵条件下土壤氮有效性的变化直接关系到入侵植物与本地植物的氮竞争关系和各自的氮利用策略(Liao et al., 2008; Feng et al., 2009), 从而影响外来植物的入侵程度和本地植物的消失或共存(Hu et al., 2018)。目前, 大量野外和室内栽培实验发现入侵区域与无入侵区域或入侵前后土壤不同形态氮含量(Dreiss & Volin, 2013; Cusack & Mccleery, 2014)、氮转化过程(如矿化、氨氧化、硝化)速率(Booth et al., 2003; Rossiter-Rachor et al., 2009)和相关微生物(如氨氧化细菌、硝化细菌)群落丰度(Hawkes et al., 2005; 于兴军等, 2005; Niu et al., 2007; Xiao et al., 2014)存在不同程度的差异, 为植物入侵可改变土壤氮有效性的观点提供了充足证据(Liao et al., 2008; Chen et al., 2009)。入侵后凋落物的质量和数量发生变化, 土壤氮转化过程中微生物活性的改变等与入侵前存在差异是入侵植物影响土壤氮有效性的重要机制(Lee et al., 2016; McLeod et al., 2016)(图1)。
图1
新窗口打开|下载原图ZIP|生成PPT图1外来植物入侵影响土壤氮(N)有效性的关键过程机制。
Fig. 1Major processes and mechanisms of changing soil nitrogen (N) availability influenced by exotic plant invasion.
对这些方面的研究结果和证据进行整合分析有助于揭示植物入侵对土壤氮有效性影响的普遍规律和机制(Gurevitch et al., 2018)。前人对野外和室内栽培实验进行过整合分析, 揭示了植物入侵不同程度地增加了土壤氮有效性(Liao et al., 2008; Vilà et al., 2011; Castro-Díez et al., 2014)。然而, Schittko等(2016)发现室内栽培与野外控制实验的结果并不一致, 自然入侵生态系统原位的土壤氮有效性变化幅度、主控因子和机制并不十分清楚。此外, 植物的入侵能力和地点的可入侵性共同决定着入侵后土壤氮有效性的变化幅度(Milbau et al., 2003)(图1)。不同气候带的入侵地点以及不同生活型和固氮功能的入侵植物存在生物学特性和入侵地非生物因素等方面的异质性(Liao et al., 2008)。因此很有必要对野外的原位研究进行单独的整合分析。
基于以上研究现状, 本文详细归纳了同一研究地外来植物入侵区域和无入侵区域的土壤原位氮含量, 对比和分析不同气候带(温带、亚热带、热带)的入侵地点以及不同生活型(一年生草本、多年生草本、落叶灌木、常绿灌木、落叶乔木、常绿乔木、多年生草质藤本、落叶木质藤本、常绿木质藤本)和固氮功能(固氮、非固氮)的植物入侵影响土壤氮指标的程度及其变化规律(图1), 探讨外来植物入侵影响土壤氮转化过程和有效性的机制。主要目标为: (1)确定全球尺度下植物入侵对原位土壤氮有效性的影响趋势及具体程度; (2)确定不同气候带的入侵地点以及不同生活型和固氮功能入侵植物的背景下, 植物入侵对土壤氮有效性的影响差异。
1 数据来源和分析
在Web of Science中通过关键词的单独和组合搜索查找已发表研究, 所用关键词包括: invasive plant、plant invasion、encroachment、soil nitrogen、soil nitrogen availability、soil available nitrogen、soil dissolved organic nitrogen、soil microbial biomass、soil microbial nitrogen。为了获得在原位条件下外来植物入侵对自然生态系统土壤氮有效性的影响, 我们提取和整合的数据结果同时满足3个条件: (1)属于自然陆地生态系统原位土壤的分析结果(排除培养或控制实验、农业生态系统); (2)同时分析了同一研究地点或样地内的入侵样方和无入侵样方(二者相距从几米到几百米不等)土壤氮含量; (3)入侵和无入侵的土壤类型和环境地理条件无明显差异。截止到2018年7月18日, 按上述条件共筛选到107篇文章, 具体采集的数据指标为入侵区域和无入侵区域的土壤总氮、铵态氮、硝态氮、无机氮(铵态氮和硝态氮之和)、微生物生物量氮含量。根据数据的可获得性, 统计和做图分析统一为每个生态系统所获得相应指标数据的平均值, 共有土壤总氮、铵态氮、硝态氮、无机氮、微生物生物量氮含量数据分别为118、62、71、60、11组(附件I)。采样地气候带(温带、亚热带、热带)划分基于其纬度数据。入侵植物的固氮和非固氮功能基于文献介绍和记录进行区分, 生活型(一年生草本、多年生草本、落叶灌木、常绿灌木、落叶乔木、常绿乔木、多年生草质藤本、落叶木质藤本、常绿木质藤本)基于Wikipedia (https://en.wikipedia.?org/wiki/Main_Page)、Practical Plants (http://practical-?plants.org/wiki/Practical_Plants)和文献记录进行划分。外来植物入侵区域相对于无入侵区域土壤氮指标相对变化(RV, 以%表示)的计算方法为:
RV = ((CI - CN) / CN) × 100。
其中, CI和CN分别为入侵区域土壤和无入侵区域土壤相同氮指标的值。参考Liao等(2008), 全组的RV值显著高于、低于0.0%时(独立样本t检验, 显著水平p设为0.05)表示外来植物入侵增加, 降低了对应氮指标的值。不同气候带、固氮功能和生活型之间相关指标的差异采用单因素方差分析(显著水平p设为0.05)。土壤铵态氮含量的增幅与固氮入侵植物占比(特定生活型入侵植物中, 可固氮的入侵植物株数(非物种数)的比例)、土壤硝态氮含量增幅之间的相关性采用非线性拟合分析, 土壤硝态氮含量的增幅与固氮入侵植物占比之间的相关性采用线性拟合分析。统计分析采用SPSS 25.0软件。土壤氮指标值及其RV值均表达为平均值(标准误差, SE)。
2 结果和讨论
2.1 植物入侵区域与无入侵区域的土壤氮含量差异
根据整合的数据, 入侵区域土壤的总氮含量范围为0.0%-2.7%, 平均值为(0.4 ± 0.0)% (图2A); 无入侵区域土壤的总氮含量范围为0.0%-1.9%, 平均值为(0.3 ± 0.0)% (图2A)。入侵区域相对于无入侵区域土壤总氮含量显著增加(p < 0.05), RV值为(50 ± 14)% (图2B)。从入侵植物自身的因素来看, 很多外来入侵植物具有固氮功能, 入侵植物本身会增加土壤的氮输入(Caldwell, 2006; González-Muñoz et al., 2012)。而且, 入侵植物通常根系更为发达, 能够获取和利用深层土壤氮源, 并通过凋落物将其归还到表层土壤(Li et al., 2007; Broadbent et al., 2017), 这种“氮泵”效应是增加入侵地表层土壤总氮含量的原因之一(Wei et al., 2017)。从土壤微生物因素来看, 入侵植物的生产力普遍高于本地植物, 导致入侵区域土壤有机碳、氮输入增加(van Kleunen et al., 2010; Godoy et al., 2011), 这会增加土壤的非共生固氮量(Zhang et al., 2010; Xu et al., 2012)。此外, 入侵区域土壤的微生物生物量氮含量总体也高于无入侵区域(图2), 氮固持能力的增加一定程度上减少了土壤氮淋溶丢失(Li et al., 2007)。图2
新窗口打开|下载原图ZIP|生成PPT图2入侵区域与无入侵区域土壤的氮含量(A)和入侵区域相对于无入侵区域土壤氮含量的相对变化(B) (平均值+标准误差)。*表示入侵区域相对于无入侵区域土壤氮含量变化显著(p < 0.05)。
Fig. 2Soil N contents in invaded and uninvaded areas (A) and relative variation (RV) values of soil N contents in invaded areas compared to uninvaded areas (B) (mean + SE). * indicates significant variation of soil N contents between the two types of areas (p < 0.05).
入侵区域土壤的无机氮含量范围为1.9-143.1 mg·kg-1, 平均值为(19.3 ± 3.7) mg·kg-1 (图2A); 无入侵区域土壤的无机氮含量范围为0.7-165.5 mg·kg-1, 平均值为(15.1 ± 3.4) mg·kg-1 (图2A)。其中, 入侵区域土壤的铵态氮、硝态氮含量范围分别为1.4-123.6 mg·kg-1和0.1-57.2 mg·kg-1, 平均值分别为(13.0 ± 2.8) mg·kg-1和(6.5 ± 1.3) mg·kg-1 (图2A)。无入侵区域土壤的铵态氮、硝态氮含量范围分别为0.6-157.5 mg·kg-1和0.0-51.9 mg·kg-1, 平均值分别为(10.6 ± 2.7)和(3.8 ± 1.1) mg·kg-1 (图2A)。相对于无入侵区域, 入侵区域土壤的无机氮、铵态氮和硝态氮含量显著增加(p < 0.05), RV值分别为(69 ± 25)%、(60 ± 24)%和(470 ± 115)% (图2B), 显示外来植物入侵增加了土壤氮有效性。根据上述结果, 入侵区域和无入侵区域土壤无机氮均以铵态氮为主, 表明植物入侵后土壤铵态氮占主导的化学结构特征未被改变(图2A)。此外, 入侵对土壤无机氮和占优势的铵态氮含量的影响幅度也基本和总氮的增加幅度相当(图2A)。一方面, 固氮入侵植物和被促进的土壤微生物非共生固氮能够直接增加土壤铵态氮含量(González-Muñoz et al., 2012; Xu et al., 2012)。另一方面, 入侵植物凋落物普遍具有较高的氮含量、较低的碳氮比(C:N)和木质素氮比(lignin:N)(Liao et al., 2008; Castro-Díez et al., 2014), 同时入侵区域的土壤有机质分解速率(Strickland et al., 2010)与碳氮循环酶的活性更高(Marchante et al., 2008; Sun et al., 2013; Souza-Alonso et al., 2014), 更快的土壤有机质矿化速率提高了土壤铵态氮的含量(Rossiter- achor et al., 2009)。然而, 我们发现土壤硝态氮含量的增幅远高于无机氮和铵态氮的增幅, 其平均含量增加的幅度是铵态氮的近8倍(图2B)。这表明外来植物入侵对土壤硝化作用的促进更大, 尤其相对于硝态氮丢失途径(反硝化和淋溶过程), 因此造成比例上硝态氮含量的增加更为显著。机制上, 氨氧化细菌和硝化细菌是硝态氮生产的主导者, 其丰度在很多外来入侵地被发现明显增加(Shannon- Firestone et al., 2015; McLeod et al., 2016)。主要原因是入侵后土壤矿化作用的增强产生足够的铵态氮(Liao et al., 2008), 直接增加了在自养硝化细菌转化作用下的硝态氮的产生(Cameron et al., 2012; Yang et al., 2017)。此外, 入侵植物根系发达, 能够增加土壤通气性并一定程度地抑制反硝化作用(Dassonville et al., 2011; Keser et al., 2015)。甚至, 研究发现入侵植物净初级生产力与原位土壤硝态氮水平存在显著正相关性(McLeod et al., 2016), 这可能是因为微生物对土壤还原态氮的竞争能力高于植物, 使得入侵植物被动地或者生理策略上主动地具有更高的硝态氮吸收能力或偏好(Kourtev et al., 1999; Bloom, 2015), 这也是外来植物入侵区域土壤硝态氮含量增幅较大的原因之一。
2.2 不同气候带植物入侵区域和无入侵区域的土壤氮含量差异
除了外来植物的入侵能力, 入侵地点的环境可入侵性(如土壤氮有效性水平)也是决定入侵程度和扩张速度的重要原因(Milbau et al., 2003)。不同气候带具有不同的温度和水分条件, 这是影响土壤氮转化过程和氮有效性的重要环境因素(Reich & Oleksyn, 2004; Wang et al., 2006)。本研究中, 温带、亚热带、热带地区植物入侵区域土壤总氮含量的平均值分别为(0.4 ± 0.0)%、(0.2 ± 0.1)%、(0.4 ± 0.2)% (图3A); 无入侵区域土壤总氮含量的平均值分别为(0.3 ± 0.0)%、(0.2 ± 0.1)%、(0.3 ± 0.1)% (图3A)。其中, 温带、亚热带、热带地区入侵区域相对于无入侵区域土壤总氮含量均显著增加(p < 0.05), RV值有所差异, 分别为(27.8 ± 10.6)%、(82.1 ± 38.2)%、(72.3 ± 28.0)% (图3E)。亚热带和热带地区入侵区域土壤总氮含量的增幅高于温带地区, 这可能与热带、亚热带地区的入侵植物生长速率更快(van Kleunen et al., 2010), 从而引发更为显著的“氮泵”效应有关。图3
新窗口打开|下载原图ZIP|生成PPT图3不同气候带、固氮功能、生活型分类下, 入侵区域和无入侵区域土壤的总氮(A)、铵态氮(B)、硝态氮(C)、无机氮含量(D)和入侵区域相对于无入侵区域土壤总氮(E)、铵态氮(F)、硝态氮(G)、无机氮(H)含量的相对变化(平均值+标准误差)。温带、亚热带、热带分别缩写为WD、YRD、RD; 固氮、非固氮分别缩写为F、NF; 一年生草本、多年生草本、常绿灌木、落叶灌木、常绿乔木、落叶乔木、多年生草质藤本、落叶木质藤本、常绿木质藤本分别缩写为AH、PH、ES、DS、ET、DT、PV、DV、EV。N.A.表示没有数据; 图E-H中不同小写字母表示差异显著性(p < 0.05); *表示入侵区域相对于无入侵区域土壤氮含量变化显著(p < 0.05)。
Fig. 3Soil total N (A) , NH4+-N (B) , NO3--N (C) , inorganic N (D) contents in invaded and uninvaded areas and relative variation (RV) values of soil total N (E) , NH4+-N (F) , NO3--N (G), inorganic N (H) contents in invaded areas compared to uninvaded areas among different climate zones, invasive plants with different N2-fixing functions and life forms (mean + SE). WD, YRD, and RD represent temperate, subtropical, and tropical zones, respectively; F and NF represent invasive plants with N2-fixing and non-N2-fixing functions, respectively; and AH, PH, ES, DS, ET, DT, PV, DV, and EV represent annual herb, perennial herb, evergreen shrub, deciduous shrub, evergreen tree, deciduous tree, perennial vine, deciduous vine, and evergreen vine, respectively. N.A. denotes data not available, and different letters in panels E-H indicate significant differences (p < 0.05) while * indicates significant variation of soil N contents in invaded areas compared to uninvaded areas (p < 0.05).
温带、亚热带、热带地区植物入侵区域相对于无入侵区域土壤铵态氮含量的RV值分别为(70.5 ± 42.9)%、(57.4 ± 24.6)%、(11.5 ± 11.6)% (图3F), 硝态氮含量的RV值分别为(683.0 ± 190.4)%、(183.6 ± 91.5)%、(492.5 ± 440.1)% (图3G)。对比发现, 除了热带地区入侵区域和无入侵区域土壤的铵态氮含量无显著差异, 其他气候带的入侵区域相对于无入侵区域的土壤铵态氮和硝态氮含量均显著增加(p < 0.05)。热带地区土壤氮循环更开放, 较快的土壤氨化作用(Martinelli et al., 1999)和入侵植物对铵态氮的偏好性吸收(Hu et al., 2018)可能导致入侵区域土壤铵态氮含量的增幅减少, 因此与无入侵差异不显著。总体上, 温带地区入侵区域土壤铵态氮和硝态氮含量的增幅高于亚热带和热带地区(图3F、3G)。相对而言, 温带地区较低的气温和降水量条件使得生态系统土壤无机氮水平通常较低且植物生长处于氮限制状态(Martinelli et al., 1999; Tang et al., 2017)。我们的结果表明外来植物入侵增加了土壤的无机氮含量, 这在氮矿化、硝化过程原本受非生物因素限制的生态系统或地区更加明显(图3G)。前人对比不同养分条件下植物入侵对土壤氮循环的影响, 同样发现外来植物入侵对低氮生态系统土壤氮有效性的增幅更大(Sardans et al., 2016)。
2.3 不同固氮功能、生活型的植物入侵区域和无入侵区域的土壤氮含量差异
探讨不同固氮功能和生活型入侵植物影响土壤氮有效性的差异有助于更好地理解不同外来植物入侵能力的差异性和土壤氮循环对植物入侵的反馈机制(Peña et al., 2010)。植物固氮, 即大气N2被根瘤菌还原为氨并被植物利用的过程(Vitousek et al., 2002), 是陆地生态系统氮输入的重要途径, 也是固氮植物生理生态学功能发挥的重要驱动力(Baer et al., 2006)。本研究中, 固氮和非固氮植物入侵区域相对于无入侵区域土壤总氮含量的RV值分别为(178.7 ± 50.6)%和(17.2 ± 8.7)% (图3E), 铵态氮含量的RV值分别为(174.9 ± 83.0)%和(20.3 ± 9.6)% (图3F), 硝态氮含量的RV值分别为(842.8 ± 354.8)%和(340.5± 0.0)% (图3G)。固氮和非固氮植物入侵区域相对于无入侵区域土壤总氮、铵态氮、硝态氮、无机氮含量均显著增加(p < 0.05), 但是固氮植物入侵区域土壤总氮、铵态氮、无机氮含量的增幅显著高于非固氮植物入侵(p < 0.05) (图3)。我们的结果清楚地揭示了固氮功能是入侵植物驱动土壤总氮库增加以及提高氮矿化、硝化作用的重要原因。一方面, 固氮植物入侵直接增加土壤氮输入(Galloway et al., 2004; Baer et al., 2006)的同时也一定程度减少植物群落生长的氮限制; 另一方面, 固氮植物凋落物氮含量较高, 土壤有机质分解与氮矿化速率也较高(Allison et al., 2006; Perakis & Hibbs, 2014)。不同生活型的入侵植物存在光合、生长速率、氮吸收能力和策略等诸多功能性状差异(Liao et al., 2008), 其凋落物质量和数量的差异直接关系到土壤有机质积累和分解, 碳氮循环微生物过程、速率等方面, 从而影响土壤的氮有效性(Yé et al., 2017)。该研究中, 一年生草本、多年生草本、落叶灌木、常绿灌木、落叶乔木、常绿乔木植物入侵区域相对于无入侵区域土壤总氮含量的RV值分别为(14.2 ± 8.5)%、(7.6 ± 4.7)%、(15.1 ± 11.4)%、(154.6 ± 103.8)%、(127.0 ± 37.1)%、(168.3 ± 72.7)% (图3E)。对比RV值发现, 落叶和常绿乔木植物入侵区域相对于无入侵区域土壤总氮含量的增幅总体较高, 而这两类生活型入侵植物的固氮植物占比(分别为75%和59%)高于其余4种生活型(分别为0%、13%、14%、29%)。另外, 从相对于无入侵区域土壤总氮含量增幅的数值看, 木本入侵植物高于草本入侵植物, 常绿入侵植物高于落叶入侵植物(图3E)。其中, 木本入侵植物中的固氮植物占比为44%; 草本入侵植物中的固氮植物占比为6%; 常绿入侵植物中的固氮植物占比为37%; 而落叶入侵植物中的固氮植物占比为52%。乔木植物入侵区域土壤总氮含量的增幅较大, 木本植物入侵对土壤总氮含量的增幅高于草本植物, 这主要归因于固氮植物增加氮输入和土壤总氮的积累。而常绿和落叶两种生活型入侵植物的固氮植物占比较为接近, 这主要反映常绿植物凋落物的分解速率慢于落叶植物, 氮矿化和丢失总体较低, 因此其入侵区域土壤总氮含量的增幅较大(Liao et al., 2006; Polyakova & Billor, 2008; Solly et al., 2014)。这一机制同样支持木本植物相对于草本植物入侵区域土壤总氮含量增幅较大的结果。
一年生草本、多年生草本、落叶灌木、常绿灌木、落叶乔木、常绿乔木植物入侵区域相对于无入侵区域土壤铵态氮含量的RV值分别为(8.1 ± 13.8)%、(32.7 ± 16.4)%、(1.0 ± 19.5)%、(14.2 ± 13.1)%、(26.6 ± 19.0)%、(275.6 ± 125.2)% (图3F), 硝态氮含量的RV值分别为(447.4 ± 180.7)%、(85.3 ± 24.6)%、(500.6 ± 243.9)%、(652.8 ± 553.3)%、(971.0 ± 595.0)%、(1066.8 ± 525.3)% (图3G)。不同生活型植物间凋落物质量差异是调控土壤氮循环和无机氮含量的重要植物因素(Jiang et al., 2013)。植物凋落物和土壤有机质中的氮矿化是土壤铵态氮产生的主要途径(Knops et al., 2002; Chapman et al., 2006), 随后土壤铵/氨在硝化细菌的氧化下生成硝态氮(Yang et al., 2017)。在多数陆地生态系统中, 土壤氮矿化和硝化、铵态氮和硝态氮含量之间存在正相关关系(Vitousek & Matson, 1984; Chapin III et al., 2011)。因此, 不同生活型植物入侵后土壤铵态氮和硝态氮含量可能同时增加。如果它们的增幅之间存在正相关关系, 反映了特定生活型植物入侵同步提高土壤氮矿化和硝化过程。然而, 该研究中, 只有常绿乔木植物入侵区域土壤的铵态氮含量显著增加且高于其他生活型(p < 0.05), 其余5种生活型植物入侵区域相对于无入侵区域,土壤铵态氮含量的增幅较小且相互间差异不显著(图3F)。对硝态氮而言, 所有生活型的入侵植物均显著增加了土壤硝态氮含量(p < 0.05)(图3G)。其中, 木本植物入侵后土壤硝态氮含量的增幅总体高于草本植物入侵, 常绿植物入侵后土壤硝态氮含量的增幅总体高于落叶植物入侵(图3G)。不同生活型植物入侵对土壤硝态氮含量的影响明显强于对铵态氮含量的影响, 且二者的增幅不存在明显关系(图4A)。相应土壤铵态氮和硝态氮含量增幅的变化特征不能从不同生活型植物之间(如落叶与常绿、草本和木本)凋落物数量和质量的特异性所造成的分解差异得到解释(Liao et al., 2006; Polyakova & Billor, 2008; Solly et al., 2014)。
图4
新窗口打开|下载原图ZIP|生成PPT图4不同生活型植物入侵区域相对于无入侵区域土壤铵态氮含量的相对变化与固氮入侵植物占比之间的关系(A)和土壤硝态氮含量的相对变化分别与铵态氮含量(空心符号)的相对变化、固氮入侵植物占比(实心符号)之间的关系(B)。一年生草本、多年生草本、常绿灌木、落叶灌木、常绿乔木、落叶乔木分别缩写为AH、PH、ES、DS、ET、DT。
Fig. 4Relationship between relative variation (RV) values of soil NH4+-N contents and percentage of N2-fixing invasive plants (A) and relationships between relative variation (RV) values of soil NO3--N contents and those of soil NH4+-N contents (hollow symbol), and percentage of N2-fixing invasive plants (solid symbol) (B) among different groups of invasive plants. AH, PH, ES, DS, ET, and DT represent annual herb, perennial herb, evergreen shrub, deciduous shrub, evergreen tree, and deciduous tree, respectively.
当前, 在入侵生态学和生物地球化学研究中, 探讨入侵植物功能特征与其对土壤氮循环影响幅度之间详细关系的研究还非常稀少, 其机制也亟待研究(Liao et al., 2008)。除了凋落物分解和有机氮矿化, 入侵植物根系固氮(即根瘤菌将大气N2转化为NH3的过程; Bloom, 2015)可能是控制入侵区域土壤铵态氮和硝态氮含量增加趋势和幅度的另一重要植物学因素(Baer et al., 2006)。该研究中, 我们发现入侵区域土壤铵态氮含量的增幅随固氮入侵植物占比无明显增加关系(图4A), 而硝态氮含量的增幅随固氮入侵植物占比增加呈线性增加(R2 = 0.86, p < 0.01; 图4B)。在自养硝化作用中, 作为反应底物的氨, 其含量是硝态氮生产速率的主要限制因素(Yang et al., 2017)。铵/氨的可利用性或丰度增加会增加氨氧化细菌丰度并提高硝化速率(Lu et al., 2015; Shannon-Firestone et al., 2015)。入侵植物根系固氮作用增加将直接增加硝化细菌的氨可利用性, 这可能是本研究中土壤铵态氮含量增幅小且与硝态氮含量增幅、固氮入侵植物占比关系不明显的主要原因。然而, 入侵植物固氮功能及其如何通过地上-地下生理生态学过程影响土壤氮矿化和硝化的详细机制和证据还有待进一步研究。
3 结论
本研究聚焦陆地生态系统外来植物入侵对土壤原位氮含量的影响幅度和机制。主要规律为: 植物入侵显著增加了土壤总氮、铵态氮、硝态氮、微生物生物量氮含量, 但它们的相对变化存在差异, 尤其土壤硝态氮含量增幅高达470%。分类对比发现, 植物入侵对温带地区土壤硝态氮含量的影响高于亚热带地区; 固氮植物入侵对土壤总氮、铵态氮和无机氮含量的影响高于非固氮植物; 木本植物和常绿植物入侵后土壤总氮的积累高于草本和落叶植物; 然而, 不同生活型植物入侵后土壤铵态氮含量的增幅均低于土壤硝态氮, 且发现土壤硝态氮含量的增幅随固氮入侵植物占比增加呈线性增长, 这些结果清晰地揭示了植物固氮功能对土壤氮有效性和循环过程机制的影响, 但其内部过程原理, 尤其二者之间的生物学反馈机制有待进一步研究。该研究为理解外来植物入侵成功和加剧的机制, 以及入侵生态系统氮生物地球化学循环与环境和植物功能之间的关系提供了新的见解。致谢 感谢天津大学的宋韦讲师和董玉平博士在数据分析、讨论中给予的指导。
参考文献 原文顺序
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被引期刊影响因子
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Nitrogen-fixing species can increase both the availability and cycling of nitrogen (N) in ecosystems. Autumn olive ( Elaeagnus umbellata Thunb.) is an exotic woody shrub associated with N 2-fixing actinomycetes that forms dense patches in disturbed landscapes (i.e., riparian zones adjacent to crop systems, old fields and agricultural grasslands) throughout the midwestern United States. We used paired plots dominated by either E. umbellata or C 3 grassland to test whether the shrub encroachment altered pools and fluxes of nitrogen (N) and carbon (C) in the soil. Annual mean of NO 3 concentrations in soil water collected from porous cup tension lysimeters every 2 weeks for 1 year was 20 times higher in soil beneath E. umbellata compared to grassland vegetation. Temporal variation in NO 3 leaching occurred in the shrub-encroached plots, with more nitrate leaching in the dormant season relative to the growing season. Potential net N mineralization, nitrification rates, and extractable N in the surface 10 cm of soil were also higher below E. umbellata. Following establishment of N 2-fixing shrub patches for 7 13 years, the soil C:N ratio showed a declining trend due to lower total soil C rather than an increase in N. Labile carbon pools (i.e., microbial biomass C (MBC) and soil respiration rates) were lower in surface soil below E. umbellata, which demonstrated an additional positive feedback between encroachment of E. umbellata and N export. Less demand for mineralized N due to associated N 2 fixation, coupled with higher rates of nitrification and lower microbial demand for N collectively contributed to higher export of N below the E. umbellata patched relative to the grassland system. Thus, areas invaded by this exotic N 2-fixing species may function as N sources rather than the N conserving systems typically expected early successional communities following agricultural abandonment.
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Many studies of plant nitrogen relations assess only the total amount of the element available from the soil and the total amount of the element within the plant. Nitrogen, however, is a constituent of diverse compounds that participate in some of the most energy-intensive reactions in the biosphere. The following characterizes some of these reactions, especially those that involve ammonium and nitrate, and highlights the importance of distinguishing both among the nitrogen sources available to plants and among the nitrogen forms within plants when considering plant responses to rising atmospheric CO2 concentrations.
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Plant invasions and eutrophication are pervasive drivers of global change that cause biodiversity loss. Yet, how invasive plant impacts on native species, and the mechanisms underpinning these impacts, vary in relation to increasing nitrogen (N) availability remains unclear. Competition is often invoked as a likely mechanism, but the relative importance of the above and belowground components of this is poorly understood, particularly under differing levels of N availability. To help resolve these issues, we quantified the impact of a globally invasive grass species, Agrostis capillaris, on two co-occurring native New Zealand grasses, and vice versa. We explicitly separated above- and belowground interactions amongst these species experimentally and incorporated an N addition treatment. We found that competition with the invader had large negative impacts on native species growth (biomass decreased by half), resource capture (total N content decreased by up to 75%) and even nutrient stoichiometry (native species tissue C:N ratios increased). Surprisingly, these impacts were driven directly and indirectly by belowground competition, regardless of N availability. Higher root biomass likely enhanced the invasive grass competitive superiority belowground, indicating that root traits may be useful tools for understanding invasive plant impacts. Our study shows that belowground competition can be more important in driving invasive plant impacts than aboveground competition in both low and high fertility ecosystems, including those experiencing N enrichment due to global change. This can help to improve predictions of how two key drivers of global change, plant species invasions and eutrophication, impact native species diversity.
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Scotch broom ( Cytisus scoparius) is a leguminous shrub, native to Europe that has invaded significant areas of the Pacific Northwest and rigorously competes with native vegetation. Mineral soils under scotch broom colonies and adjacent coastal prairie on the Mendocino Coast of Northern California were sampled to determine how soil properties and microbial processes have been affected. Soils under scotch broom were significantly more acidic and had greater organic matter content than prairie soils. The activities of two soil enzymes responsible for processing major detrital carbon and phosphorus pools were significantly higher under scotch broom. Organic matter accumulation with no change in C:N, a greater increase in phosphatase activity (123%) than in -glucosidase (84%) under scotch broom, and a significant difference between soil C:P under scotch broom (619) and prairie vegetation (470) all suggest that the coupling of nutrient cycles has changed.
DOI:10.1111/aab.12014URL [本文引用: 1]
Losses of nitrogen from the soil/plant system not only reduce soil fertility and plant yield but can also create adverse impacts on the environment. Ammonia emissions into the atmosphere contribute to acid rain and represent an indirect source of nitrous oxide greenhouse gas emissions. Nitrate leaching losses into rivers and lakes can cause eutrophication resulting in excessive growth of aquatic weeds and algae, which can reduce fish populations and the recreational value of the water. Nitrate contamination of drinking water supplies can cause health risks. Legislation that is designed to limit nitrate leaching losses from land has become a constraint on agricultural land use in many countries. Nitrous oxide emissions into the atmosphere contribute to the depletion of the ozone layer and also make a significant contribution to climate change. This review describes the nitrogen cycle in temperate soil/plant systems, the processes involved in each of the individual nitrogen loss pathways, the factors affecting the amounts of losses and the methods that are available to reduce these losses. The review has shown that careful management of temperate soil/plant systems using best management practices and newly developed technologies can increase the sustainability of agriculture and reduce its impact on the environment.
DOI:10.1111/ele.12197URLPMID:24134461 [本文引用: 2]
Exotic plant invasions can notably alter the nitrogen (N) cycle of ecosystems. However, there is large variation in the magnitude and direction of their impact that remains unexplained. We present a structured meta-analysis of 100 papers, covering 113 invasive plant species with 345 cases of invasion across the globe and reporting impacts on N cycle-related metrics. We aim to explain heterogeneity of impacts by considering methodological aspects, properties of the invaded site and phylogenetic and functional characteristics of the invaders and the natives. Overall, plant invasions increased N pools and accelerated fluxes, even when excluding N-fixing invaders. The impact on N pools depended mainly on functional differences and was greater when the invasive plants and the natives differed in N-fixation ability, plant height and plant/leaf habit. Furthermore, the impact on N fluxes was related mainly to climate, being greater under warm and moist conditions. Our findings show that more functionally distant invaders occurring in mild climates are causing the strongest alterations to the N cycle.
2nd edn.
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Ecologists have tried to link plant species composition and ecosystem properties since the inception of the ecosystem concept in ecology. Many have observed that biological communities could feed back to, and not simply result from, soil properties. But which group of organisms, plants or microorganisms, drive those feedback systems? Recent research asserts that soil microorganisms preclude plant species feedback to soil nitrogen (N) transformations due to strong microbial control of soil N cycling. It has been well documented that litter properties influence soil N cycling. In this review, we stress that under many circumstances plant species exert a major influence over soil N cycling rates via unique N attainment strategies, thus influencing soil N availability and their own fitness. We offer two testable mechanisms by which plants impart active control on the N cycle and thereby allow for plant-litter-soil-plant feedback. Finally, we describe the characteristics of plants and ecosystems that are most likely to exhibit feedback.
DOI:10.1007/s10530-008-9336-9URL [本文引用: 1]
Allelopathy has been regarded as a mechanism for successful exotic plant invasion. However, it is not clear if and what effects of allelopathic substances may exert on soil nutrient. The exotic plant Mikania micrantha H.B.K. ( M. micrantha ) has invaded many forests in south China, and recent studies have suggested it has allelopathic potential for other plants and soil microbial community. Thus, we hypothesized that M. micrantha could influence soil nutrients and N transformation through allelopathy. We measured total C and N, NO 3 61 , NH 4 + and pH of the soil beneath M. micrantha and the adjacent open soil, and then measured the above soil properties after treating soil with 3 concentrations of aqueous extracts of M. micrantha (T 1 : 0.00502g02ml 611 ; T 2 : 0.02502g02ml 611 ; T 3 : 0.10002g02ml 611 ). In addition, a bioassay was conducted to determine the allelopathic potential of the soil beneath M . micrantha . The results showed that M . micrantha significantly affected soil nutrients and N transformation. Soil beneath M. micrantha had inhibitory effects on seed germination and seedling growth of test plant, and had significantly higher C, N, ammonia, net nitrification rate than those of open soil. The plant extracts decreased soil pH, and T 1 decreased it the most, and it increased soil C and N, and T 1 represented the greatest increase in both C and N. The extracts also increased both NO 3 61 and NH 4 + in soil, whereas no significant difference existed among the 3 extract treatments. Compared to the water control, the soil net mineralization rate was higher under T 1 , while lower under T 2 and T 3 . However, the extracts increased the soil nitrification rates under all the treatments (T 1 , T 2 and T 3 ). Our results suggest that the water soluble allelochemicals of M . micrantha improve soil nutrient availability, through which the invasive plant M. micrantha may successfully invade and establish in new habitats.
DOI:10.1016/j.foreco.2013.12.036URL [本文引用: 1]
Urban expansion is accelerating in the tropics, and may promote the spread of introduced plant species into urban-proximate forests. For example, soil disturbance can deplete the naturally high soil nitrogen pools in wet tropical soils, favoring introduced species with nitrogen-fixing capabilities. Also, forest fragmentation and canopy disturbance are likely to favor high-light species over shade-adapted rainforest species. We measured understory woody diversity, the abundance of introduced species, and soil nitrogen and carbon in urban, suburban, and rural secondary forests in Puerto Rico with canopies dominated by (1) native species, (2) introduced Fabaceae (potential nitrogen-fixers), and (3) introduced non-Fabaceae species. We hypothesized that forest stands with introduced Fabaceae in the canopy have higher soil nitrogen levels than stands with other introduced canopy species, and that this higher nitrogen is linked to increased native woody species diversity in the understory. We also predicted that more open canopies and smaller fragment sizes would be positively related with introduced species in the understory, and negatively related with total understory diversity. We found that stands with introduced Fabaceae in the canopy had significantly higher soil nitrogen levels than stands with other non-nitrogen fixing introduced species, and understory woody diversity in Fabaceae stands approached similar diversity levels as stands with native-dominated canopies. As predicted, aboveground stand structure and fragment size were also significantly associated with understory woody diversity across stands. These results suggest that introduced nitrogen-fixing trees may improve recruitment of native woody species in degraded tropical sites where native soil nitrogen is naturally high, particularly as Fabaceae stands mature and canopies close.
DOI:10.1007/s10530-011-9954-5URL [本文引用: 1]
Big Asian knotweeds ( Fallopia spp .) are among the most invasive plant species in north-western Europe. We suggest that their success is partially explained by biological and chemical niche construction. In this paper, we explored the microbial mechanisms by which the plant modifies the nitrogen cycle. We found that Fallopia spp . decreased potential denitrification enzyme activity (DEA) by reducing soil moisture and reducing denitrifying bacteria density in the soil. The plant also reduced potential ammonia and nitrite oxydizing bacteria enzyme activities (respectively, AOEA and NOEA) in sites with high AOEA and NOEA in uninvaded situation. Modification of AOEA and NOEA were not correlated to modifications of the density of implicated bacteria. AOB and Nitrobacter -like NOB community genetic structures were significantly different in respectively two and three of the four tested sites while the genetic structure of denitrifying bacteria was not affected by invasion in none of the tested sites. Modification of nitrification and denitrification functioning in invaded soils could lead to reduced nitrogen loss from the ecosystem through nitrate leaching or volatilization of nitrous oxides and dinitrogen and could be considered as a niche construction mechanism of Fallopia.
DOI:10.1641/B580407URL [本文引用: 1]
China has undergone enormous economic growth in the last 25 years, largely as a result of greatly increased international trade. This burgeoning trade has triggered environmental threats from an expanding list of biological invaders: nonnative species previously unknown in China (e.g., the American vegetable leaf miner, the fall webworm) have arrived and are already causing damage to China's environment and economy. Huge construction projects, such as the Three Gorges Dam and the recently completed rail link to Tibet, could further spread invasive species to once-isolated portions of the country. The environmental risks from this onslaught are immense: China is one of the world's hotspots of biodiversity with about 30,000 native species of vascular plants and at least 2340 species of native terrestrial vertebrates. Fostering governmental and public awareness in China of the costs of invasive species and the multiple benefits of their prevention and control will be key to countering this menace.
DOI:10.1016/j.foreco.2013.01.031URL [本文引用: 1]
Invasion by nonnative species is considered one of the greatest threats to ecosystem structure and function worldwide. Human disturbance and landscape fragmentation create edge habitats that are often higher in resource (i.e., light and nutrient) availability and are noted for having a high degree of invasive species establishment and colonization. In contrast, interior forest understories, which are often light- and nutrient-limited, are typically less susceptible to invasion. We assessed invasive species presence in interior, intact, temperate forest understories in relation to canopy-induced environmental conditions. We hypothesized that nonnative invasive species presence would be greatest under those canopy tree species that allow higher understory light and/or soil nitrate levels as a result of inherent differences in canopy transmission, spring leaf phenology, and nitrogen fixation. Five native forest canopy types were used, Populus tremuloides (quaking aspen), Acer saccharum (sugar maple), Quercus spp./Carya spp. (oak/hickory), Fraxinus americana (white ash), evergreen species mix Pinus spp./Tsuga canadensis (pine/hemlock), along with one nonnative canopy species, Robinia pseudoacacia (black locust). Measures of understory light availability post leaf-expansion were significantly higher under quaking aspen than other canopies with the exception of black locust and white ash. Canopy bud break and leaf flush occurred first in quaking aspen stands followed by sugar maple, oak/hickory, white ash and black locust stands, respectively. As expected, soil analyses showed higher nitrate levels in the nitrogen-fixing black locust stands, but unexpectedly, also in the white ash stands. Under these two canopy types, invasive species cover and relative abundance were significantly higher suggesting the importance of greater resource availability in invasive plant success. As such, intact forest stands with greater light transmission, later phenology, and nitrate fixation act as islands of invasion in resource-limited forested landscapes.
DOI:10.1007/s10021-002-0151-3URL [本文引用: 1]
DOI:10.1073/pnas.0808434106URL [本文引用: 1]
Many studies have shown that individuals from invasive populations of many different plant species grow larger than individuals from native populations and that this difference has a genetic basis. This increased vigor in invasive populations is thought to be due to life history tradeoffs, in which selection favors the loss of costly defense traits, thereby freeing resources that can be devoted to increased growth or fecundity. Despite the theoretical importance of such allocation shifts for invasions, there have been no efforts to understand apparent evolutionary shifts in defensegrowth allocation mechanistically. Real location of nitrogen (N) to photosynthesis is likely to play a crucial role in any growth increase; however, no study has been conducted to explore potential evolutionary changes in N allocation of introduced plants. Here, we show that introduced Ageratina adenophora. a noxious invasive plant throughout the subtropics, appears to have evolved increased N allocation to photosynthesis (growth) and reduced allocation to cell walls, resulting in poorer structural defenses. Our results provide a potential mechanism behind the commonly observed and genetically based increase in plant growth and vigor when they are introduced to new ranges.
DOI:10.1007/s10533-004-0370-0URL [本文引用: 1]
This paper contrasts the natural and anthropogenic controls on the conversion of unreactive N2to more reactive forms of nitrogen (Nr). A variety of data sets are used to construct global N budgets for 1860 and the early 1990s and to make projections for the global N budget in 2050. Regional N budgets for Asia, North America, and other major regions for the early 1990s, as well as the marine N budget, are presented to highlight the dominant fluxes of nitrogen in each region. Important findings are that human activities increasingly dominate the N budget at the global and at most regional scales, the terrestrial and open ocean N budgets are essentially disconnected, and the fixed forms of N are accumulating in most environmental reservoirs. The largest uncertainties in our understanding of the N budget at most scales are the rates of natural biological nitrogen fixation, the amount of Nr storage in most environmental reservoirs, and the production rates of N2by denitrification.
DOI:10.1111/j.1365-2435.2011.01886.xURL [本文引用: 1]
1. Plastic responses to spatiotemporal environmental variation strongly influence species distribution, with widespread species expected to have high phenotypic plasticity. Theoretically, high phenotypic plasticity has been linked to plant invasiveness because it facilitates colonization and rapid spreading over large and environmentally heterogeneous new areas.2. To determine the importance of phenotypic plasticity for plant invasiveness, we compare well-known exotic invasive species with widespread native congeners. First, we characterized the phenotype of 20 invasive native ecologically and phylogenetically related pairs from the Mediterranean region by measuring 20 different traits involved in resource acquisition, plant competition ability and stress tolerance. Second, we estimated their plasticity across nutrient and light gradients.3. On average, invasive species had greater capacity for carbon gain and enhanced performance over a range of limiting to saturating resource availabilities than natives. However, both groups responded to environmental variations with high albeit similar levels of trait plasticity. Therefore, contrary to the theory, the extent of phenotypic plasticity was not significantly higher for invasive plants.4. We argue that the combination of studying mean values of a trait with its plasticity can render insightful conclusions on functional comparisons of species such as those exploring the performance of species coexisting in heterogeneous and changing environments.
[本文引用: 2]
DOI:10.1038/nature25753URL [本文引用: 1]
1. The number of published meta-analyses in plant ecology has increased greatly over the last two decades. Meta-analysis has made a significant contribution to the field, allowing review of evidence for various ecological hypotheses and theories, estimation of effects of major environmental drivers (climate change, habitat fragmentation, invasive species, air pollution), assessment of... [Show full abstract]
DOI:10.1111/j.1461-0248.2005.00802.xURL [本文引用: 1]
Plant invasions have dramatic aboveground effects on plant community composition, but their belowground effects remain largely uncharacterized. Soil microorganisms directly interact with plants and mediate many nutrient transformations in soil. We hypothesized that belowground changes to the soil microbial community provide a mechanistic link between exotic plant invasion and changes to ecosystem nutrient cycling. To examine this possible link, monocultures and mixtures of exotic and native species were maintained for 4 years in a California grassland. Gross rates of nitrogen (N) mineralization and nitrification were quantified with 15N pool dilution and soil microbial communities were characterized with DNA-based methods. Exotic grasses doubled gross nitrification rates, in part by increasing the abundance and changing the composition of ammonia-oxidizing bacteria in soil. These changes may translate into altered ecosystem N budgets after invasion. Altered soil microbial communities and their resulting effects on ecosystem processes may be an invisible legacy of exotic plant invasions.
[本文引用: 2]
DOI:10.1007/s11104-013-1859-xURL [本文引用: 1]
Litter, as afterlife of plants, plays an important role in driving belowground decomposition processes. Here we tested effects of litter species identity and diversity on carbon (C) and nitrogen (N) dynamics during litter decomposition in N-limited alpine meadow soil from the Qinghai-Tibet Plateau.We incubated litters of four meadow species, a sedge ("S", Kobresia humilis), a grass ("G", Elymus nutans), a herb ("H", Saussurea superba), and a legume ("L", Oxytropis falcata), in monoculture and in mixture with meadow soil. CO2 release was measured 21 times during the incubation, and soil available N and microbial biomass C and N were measured before and after the experiment.The organic C decay rate did not differ much among soils amended with monocultures or mixtures of litter, except in the H, S, L, and S+H treatments, which had much higher decay rates. Potential decomposable C pools were lowest in the control, highest in the L treatment, and intermediate in the S treatment. Mineralized N was completely immobilized by soil microbes in all treatments except the control, S+L, and S+G+L treatments. Litter mixtures had both additive and non-additive effects on CO2-C emission (mainly antagonistic effects), net N mineralization (mainly synergistic), and microbial biomass C and N (both). Overall, these parameters were not significantly correlated with litter species richness. Similarly, microbial C or N was not significantly correlated with litter N content or C/N. However, cumulative CO2-C emission and net N mineralization were positively correlated with litter N content and negatively correlated with litter C/N.Litter N content and C/N rather than litter species richness drove the release of CO2-C and net available N in this ecosystem. The antagonistic effects of litter mixtures contributed to a modest release of CO2-C, but their synergistic effects enhanced net available N. We suggest that in alpine meadow communities, balancing species with high and low N contents will benefit soil carbon sequestration and plant competition for available N with soil microbes.
DOI:10.3389/fpls.2015.00273URLPMID:4410514 [本文引用: 1]
Although plastic root-foraging responses are thought to be adaptive, as they may optimize nutrient capture of plants, this has rarely been tested. We investigated whether nutrient-foraging responses are adaptive, and whether they pre-adapt alien species to become natural-area invaders. We grew 12 pairs of congeneric species (i.e. 24 species) native to Europe in heterogeneous and homogeneous nutrient environments, and compared their foraging responses and performance. One species in each pair is a USA natural-area invader, and the other one is not. Within species, individuals with strong foraging responses, measured as root diameter and specific root length, had a higher biomass. Among species, the ones with strong foraging responses, measured as root length and root biomass, had a higher biomass. Our results therefore suggest that root foraging is an adaptive trait. Invasive species showed significantly stronger root-foraging responses than non-invasive species when measured as root diameter. Biomass accumulation was decreased in the heterogeneous versus the homogeneous environment. In aboveground, but not belowground and total biomass, this decrease was smaller in invasive than in non-invasive species. Our results show that strong plastic root-foraging responses are adaptive, and suggest that it might aid in pre-adapting species to becoming natural-area invaders.
DOI:10.1046/j.1461-0248.2002.00332.xURL [本文引用: 1]
Plant species are hypothesized to impact ecosystem nitrogen cycling in two distinctly different ways. First, differences in nitrogen use efficiency can lead to positive feedbacks on the rate of nitrogen cycling. Alternatively, plant species can also control the inputs and losses of nitrogen from ecosystems.Our current understanding of litter decomposition shows that most nitrogen present within litter is not released during decomposition but incorporated into soil organic matter. This nitrogen retention is caused by an increase in the relative nitrogen content in decomposing litter and a much lower carbon-to-nitrogen ratio of soil organic matter. The long time lag between plant litter formation and the actual release of nitrogen from the litter results in a bottleneck, which prevents feedbacks of plant quality differences on nitrogen cycling. Instead, rates of gross nitrogen mineralization, which are often an order of magnitude higher than net mineralization, indicate that nitrogen cycling within ecosystems is dominated by a microbial nitrogen loop. Nitrogen is released from the soil organic matter and incorporated into microbial biomass. Upon their death, the nitrogen is again incorporated into the soil organic matter. However, this microbial nitrogen loop is driven by plant-supplied carbon and provides a strong negative feedback through nitrogen cycling on plant productivity. Evidence supporting this hypothesis is strong for temperate grassland ecosystems. For other terrestrial ecosystems, such as forests, tropical and boreal regions, the data are much more limited. Thus, current evidence does not support the view that differences in the efficiency of plant nitrogen use lead to positive feedbacks.In contrast, soil microbes are the dominant factor structuring ecosystem nitrogen cycling. Soil microbes derive nitrogen from the decomposition of soil organic matter, but this microbial activity is driven by recent plant carbon inputs. Changes in plant carbon inputs, resulting from plant species shifts, lead to a negative feedback through microbial nitrogen immobilization. In contrast, there is abundant evidence that plant species impact nitrogen inputs and losses, such as: atmospheric deposition, fire-induced losses, nitrogen leaching, and nitrogen fixation, which is driven by carbon supply from plants to nitrogen fixers. Additionally, plants can influence the activity and composition of soil microbial communities, which has the potential to lead to differences in nitrification, denitrification and trace nitrogen gas losses. Plant species also impact herbivore behaviour and thereby have the potential to lead to animal-facilitated movement of nitrogen between ecosystems.Thus, current evidence supports the view that plant species can have large impacts on ecosystem nitrogen cycling. However, species impacts are not caused by differences in plant quantity and quality, but by plant species impacts on nitrogen inputs and losses.
DOI:10.1023/A:1010048909563URL [本文引用: 1]
DOI:10.1111/nph.14115URLPMID:27501517 [本文引用: 1]
61 Many exotic species have little apparent impact on ecosystem processes, whereas others have dramatic consequences for human and ecosystem health. There is growing evidence that invasions foster eutrophication. We need to identify species that are harmful and systems that are vulnerable to anticipate these consequences. Species’ traits may provide the necessary insights.61 We conducted a global meta-analysis to determine whether plant leaf and litter functional traits, and particularly leaf and litter nitrogen (N) content and carbon: nitrogen (C : N) ratio, explain variation in invasive species’ impacts on soil N cycling.61 Dissimilarity in leaf and litter traits among invaded and noninvaded plant communities control the magnitude and direction of invasion impacts on N cycling. Invasions that caused the greatest increases in soil inorganic N and mineralization rates had a much greater litter N content and lower litter C : N in the invaded than the reference community. Trait dissimilarities were better predictors than the trait values of invasive species alone.61 Quantifying baseline community tissue traits, in addition to those of the invasive species, is critical to understanding the impacts of invasion on soil N cycling.
URL [本文引用: 1]
越来越多的证据表明,入侵植物能通过杂交和基因渐渗等对本地种造成遗传侵蚀,甚至产生新的"基因型"来影响本地种的遗传多样性;通过生境片断化,改变本地种种群内和种群间的基因交流,造成近亲繁殖和遗传漂变,间接影响本地种的遗传多样性。另一方面,本地种能对入侵植物做出适应性进化响应,以减小或消除入侵植物的危害。本地种在与入侵植物的互作过程中产生了一系列的适应进化、物种形成以及灭绝事件,且这些事件不仅局限于地上生态系统,土壤生物多样性同样受到影响,甚至也能发生进化响应。为更全面地了解外来植物入侵的生态后果和本地生物的适应潜力,本文综述了外来植物入侵对本地(地上和地下)生物(遗传)多样性的影响以及本地生物的进化响应,讨论了外来植物入侵导致的遗传和进化变化与其入侵性的关系,并提出了一些值得研究的课题,如土著种与外来种的协同进化、植物―土壤反馈调节途径和全球变化其他组分与生物入侵的关系等。
URL [本文引用: 1]
越来越多的证据表明,入侵植物能通过杂交和基因渐渗等对本地种造成遗传侵蚀,甚至产生新的"基因型"来影响本地种的遗传多样性;通过生境片断化,改变本地种种群内和种群间的基因交流,造成近亲繁殖和遗传漂变,间接影响本地种的遗传多样性。另一方面,本地种能对入侵植物做出适应性进化响应,以减小或消除入侵植物的危害。本地种在与入侵植物的互作过程中产生了一系列的适应进化、物种形成以及灭绝事件,且这些事件不仅局限于地上生态系统,土壤生物多样性同样受到影响,甚至也能发生进化响应。为更全面地了解外来植物入侵的生态后果和本地生物的适应潜力,本文综述了外来植物入侵对本地(地上和地下)生物(遗传)多样性的影响以及本地生物的进化响应,讨论了外来植物入侵导致的遗传和进化变化与其入侵性的关系,并提出了一些值得研究的课题,如土著种与外来种的协同进化、植物―土壤反馈调节途径和全球变化其他组分与生物入侵的关系等。
URL [本文引用: 1]
篇首： 今天,乘坐飞机长途旅行已是一件太普通不过的事情了,我们可以在不到一天的时间内到达世界的任何大城市.在我们的孩提时代,世界大城市是‘那么的遥不可 及,而今只不过是邻近的"小村落"而已,世界变得越来越小.近代技术革新所带来的空间上的相对变小不仅给我们人类的各种交往和商业活动带来了便捷,而且也 有助于生物物种越过自然的物理屏障,进行快速和低风险的长距离扩散,从而重塑物种的分布区.从这种意义上来说.全球化就像地质事件一样,对物种的分布区产 生着深刻的影响.就全球范围来看,由人类有意或无意"嫁到"新的地理分布区的物种总数可能已达到50万种之多(Pimentel et a1..2001).
URL [本文引用: 1]
篇首： 今天,乘坐飞机长途旅行已是一件太普通不过的事情了,我们可以在不到一天的时间内到达世界的任何大城市.在我们的孩提时代,世界大城市是‘那么的遥不可 及,而今只不过是邻近的"小村落"而已,世界变得越来越小.近代技术革新所带来的空间上的相对变小不仅给我们人类的各种交往和商业活动带来了便捷,而且也 有助于生物物种越过自然的物理屏障,进行快速和低风险的长距离扩散,从而重塑物种的分布区.从这种意义上来说.全球化就像地质事件一样,对物种的分布区产 生着深刻的影响.就全球范围来看,由人类有意或无意"嫁到"新的地理分布区的物种总数可能已达到50万种之多(Pimentel et a1..2001).
DOI:10.1007/s11104-007-9310-9URL [本文引用: 2]
The relationship between Mikania micrantha invasion and soil microbial communities was studied across the invasive gradients varying from 0 to 38, 80, and 100% coverage of M. micrantha. The results showed microbial biomass C, N, and P all increased as the cover of M. micrantha increased. Soil microbial quotient Cmic/Corg (microbial biomass C/organic C) tended to increase linearly with the cover of M. micrantha. Basal respiration (BR) also showed a similar trend. The respiratory quotient qCO2 decreased with M. micrantha invasion, and remained at quite a constantly low level in the invasive soils. Community level physiological profiles (CLPP) analyses indicated that M. micrantha invasion tended to result in higher average well color development, substrate richness, and functional diversity. Average utilization of specific substrate guilds was highest in M. micrantha monoculture. Principle component analysis of CLPP further indicated that M. micrantha monoculture was distinctly separated from the native area and the ecotones. In conclusion, M. Mikania invasion improved soil microbial biomass, respiration and utilization of carbon sources, and decreased qCO2, thus created better soil conditions, which in turn were more conducive to the growth of M. micrantha.
DOI:10.1111/nph.2008.177.issue-3URL [本文引用: 9]
DOI:10.1016/j.soilbio.2006.04.004URL [本文引用: 2]
Soil physical structure causes differential accessibility of soil organic carbon (SOC) to decomposer organisms and is an important determinant of SOC storage and turnover. Techniques for physical fractionation of soil organic matter in conjunction with isotopic analyses (δ 13C, δ 15N) of those soil fractions have been used previously to (a) determine where organic C is stored relative to aggregate structure, (b) identify sources of SOC, (c) quantify turnover rates of SOC in specific soil fractions, and (d) evaluate organic matter quality. We used these two complementary approaches to characterize soil C storage and dynamics in the Rio Grande Plains of southern Texas where C 3 trees/shrubs (δ 13C=6127‰) have largely replaced C 4 grasslands (δ 13C=6114‰) over the past 100–200 years. Using a chronosequence approach, soils were collected from remnant grasslands (Time 0) and from woody plant stands ranging in age from 10 to 130 years. We separated soil organic matter into specific size/density fractions and determined their C and N concentrations and natural δ 13C and δ 15N values. Mean residence times (MRTs) of soil fractions were calculated based on changes in their δ 13C with time after woody encroachment. The shortest MRTs (average=30 years) were associated with all particulate organic matter (POM) fractions not protected within aggregates. Fine POM (53–250 μm) within macro- and microaggregates was relatively more protected from decay, with an average MRT of 60 years. All silt+clay fractions had the longest MRTs (average=360 years) regardless of whether they were found inside or outside of aggregate structure. δ 15N values of soil physical fractions were positively correlated with MRTs of the same fractions, suggesting that higher δ 15N values reflect an increased degree of humification. Increased soil C and N pools in wooded areas were due to both the retention of older C 4-derived organic matter by protection within microaggregates and association with silt+clay, and the accumulation of new C 3-derived organic matter in macroaggregates and POM fractions.
DOI:10.1016/j.soilbio.2015.02.034URL [本文引用: 1]
61Activities of ammonia-oxidizing archaea and bacteria were determined using 1-octyne.61Activity of ammonia-oxidizing archaea was highly correlated to their abundance.61Activity of ammonia-oxidizing bacteria was not correlated to their abundance.61Activity of ammonia-oxidizing archaea was related more to soil C:N ratio than to pH.61Activity of ammonia-oxidizing bacteria was associated with soil pH.
DOI:10.1016/j.apsoil.2008.04.004URL [本文引用: 1]
Many coastal dune ecosystems in Portugal are invaded by the leguminous tree Acacia longifolia (Andrews) Willd. This exotic species was first introduced over one hundred years ago in an effort to mitigate dune erosion and loss of coastal landscapes. However, since then A. longifolia has spread to new areas, displacing the native vegetation. These invaded ecosystems contrast with the native dune ecosystems that are typically dominated by herb and shrub communities. This study characterizes belowground changes to the native environment as a result of recent (<10 y) and long-term invasion (>20 y) by A. longifolia by analyzing a range of chemical and microbial parameters. Both invaded areas accumulated higher litter densities with greater N contents and lower C/N ratios than the native areas, which corresponded to lower C/N ratio and to higher potential rates of nitrification in the invaded soils. Long-term occupation by A. longifolia has significantly altered the soil properties with increased levels of organic C, total N and exchangeable cations resulting in higher microbial biomass, basal respiration, and -glucosaminidase activity. However, basal respiration and microbial biomass were significantly higher within recent invasion sites when calculated relative to soil organic C. The results from this study show that invasions by A. longifolia have altered the original native ecosystem processes and that the impacts are more pronounced within long-term invaded sites. A positive feedback mechanism is apparent for A. longifolia invading these Mediterranean dunes, which can make the restoration of native plant communities increasingly difficult with time elapsed since invasion.
DOI:10.1007/BF01007573URL [本文引用: 2]
Several lines of evidence suggest that nitrogen in most tropical forests is relatively more available than N in most temperate forests, and even that it may function as an excess nutrient in many tropical forests. If this is correct, tropical forests should have more open N cycles than temperate forests, with both inputs and outputs of N large relative to N cycling within systems. Consequent differences in both the magnitude and the pathways of N loss imply that tropical forests should in general be more 15N enriched than are most temperate forests. In order to test this hypothesis, we compared the nitrogen stable isotopic composition of tree leaves and soils from a variety of tropical and temperate forests. Foliar δ 15N values from tropical forests averaged 6.5‰ higher than from temperate forests. Within the tropics, ecosystems with relatively low N availability (montane forests, forests on sandy soils) were significantly more depleted in 15N than other tropical forests. The average δ 15N values for tropical forest soils, either for surface or for depth samples, were almost 8‰ higher than temperate forest soils. These results provide another line of evidence that N is relatively abundant in many tropical forest ecosystems.
DOI:10.1111/1365-2745.12584URL [本文引用: 3]
Summary Exotic plant invasion is often associated with dramatic increases in above-ground net primary productivity and soil nitrogen. However, most evidence for these increases comes from correlative studies of single species, leaving open the question of whether invasive plants drive these processes and whether they are consistent among invaders. We combined field surveys and measurements within experimental plantings to examine how plant productivity, soil nitrogen and the abundance of ammonia-oxidizing bacteria (AOB) change in response to invasions by four exotic species. The relationship between plant productivity and soil nitrate differed among native and invasive species, suggesting a fundamental disparity in the effects of natives and invaders on ecosystem processes. In field surveys, dense patches of all invasive species had higher abundances of AOB than native-dominated sites. Three of the four invasive species had higher productivity, soil nitrate concentrations and rates of potential nitrification as compared to nearby native-dominated communities. In our experimental plantings, we found that two invasive species drove increases in soil nitrate and one invader caused increased productivity after a single season. Synthesis . Our results highlight the importance of the N cycling soil microbial community in how exotic invasive plants alter ecosystem function and show that shifts in function can occur rapidly.
DOI:10.2307/1514264URL [本文引用: 2]
http://www.jstor.org/stable/1514264
[本文引用: 1]
[本文引用: 1]
DOI:10.1007/s10021-012-9579-2URL [本文引用: 1]
Abstract-fixing tree species can accelerate ecosystem N dynamics through decomposition feedbacks via both direct and indirect pathways. Direct pathways include the production of readily decomposed leaf litter and increased N supply to decomposers, whereas indirect pathways include increased tissue N and altered detrital dynamics of non-fixing vegetation. To evaluate the relative importance of direct and indirect pathways, we compared 3-year decomposition and N dynamics of N-fixing red alder leaf litter (2.34% N) to both low-N (0.68% N) and high-N (1.21% N) litter of non-fixing Douglas-fir, and decomposed each litter source in four forests dominated by either red alder or Douglas-fir. We also used experimental N fertilization of decomposition plots to assess elevated N availability as a potential mechanism of N-fixer effects on litter mass loss and N dynamics. Direct effects of N-fixing red alder on decomposition occurred primarily as faster N release from red alder than Douglas-fir litter. Direct increases in N supply to decomposers via experimental N fertilization did not stimulate decomposition of either species litter. Fixed N indirectly influenced detrital dynamics by increasing Douglas-fir tissue and litter N concentrations, which accelerated litter N release without accelerating mass loss. By increasing soil N, tissue N, and the rate of N release from litter of non-fixers, we conclude that N-fixing vegetation can indirectly foster plant oil feedbacks that contribute to the persistence of elevated N availability in terrestrial ecosystems.
DOI:10.1016/j.ecolecon.2004.10.002URL [本文引用: 1]
Invading alien species in the United States cause major environmental damages and losses adding up to almost $120 billion per year. There are approximately 50,000 foreign species and the number is increasing. About 42% of the species on the Threatened or Endangered species lists are at risk primarily because of alien-invasive species.
DOI:10.1016/j.foreco.2007.06.049URL [本文引用: 2]
This study is focused on the decomposition rates and chemical composition in pure pine (Pinus taeda L.) and mixed pine-deciduous litter. Litter bags contained either 100% loblolly pine needles or 80% loblolly pine needles and 20% leaves of one of five deciduous species: yellow poplar (Liriodendron tulipifera L.), elm (Ulmus americana L.), sweetgum (Liquidambar styraciflua L.), water oak (Quercus nigra L.) or red oak (Q. falcata L.) were incubated in a loblolly pine stand in Auburn, AL. Decomposition rates and changes in carbon (C), nitrogen (N) and phosphorus (P) concentration and content were measured during one year of incubation. Mixed litter had higher initial ash and N concentrations, increased decomposition rates, and narrow C:N ratio compared to a pure pine litter. Small amounts of yellow poplar, sweetgum and water oak litter significantly increased initial P concentration in mixed litter. Decomposition rates were highest in elm-pine mix, followed by mixes with red oak and yellow poplar. Pine-elm mix had the highest N and P accumulation-release rates, allowing us to conclude that elm would cause the greatest N and P cycling increase in pine stands. Deciduous species, particularly elm, red oak and yellow poplar, may be considered as an ameliorative species to increase nutrient circulation in pine stands. (c) 2007 Elsevier B.V. All rights reserved.
DOI:10.1073/pnas.0403588101URL [本文引用: 1]
[本文引用: 2]
DOI:10.1111/gcb.13384URLPMID:27272953 [本文引用: 2]
Abstract Plant invasion is an emerging driver of global change worldwide. We aimed to disentangle its impacts on plant-soil nutrient concentrations. We conducted a meta-analysis of 215 peer-reviewed articles and 1233 observations. Invasive plant species had globally higher N and P concentrations in photosynthetic tissues but not in foliar litter, in comparison with their native competitors. Invasive plants were also associated with higher soil C and N stocks and N, P, and K availabilities. The differences in N and P concentrations in photosynthetic tissues and in soil total C and N, soil N, P, and K availabilities between invasive and native species decreased when the environment was richer in nutrient resources. The results thus suggested higher nutrient resorption efficiencies in invasive than in native species in nutrient-poor environments. There were differences in soil total N concentrations but not in total P concentrations, indicating that the differences associated to invasive plants were related with biological processes, not with geochemical processes. The results suggest that invasiveness is not only a driver of changes in ecosystem species composition but that it is also associated with significant changes in plant-soil elemental composition and stoichiometry. 2016 John Wiley & Sons Ltd.
DOI:10.1111/1365-2745.12603URL [本文引用: 1]
Summary Plant–soil feedback (PSF) may affect above-ground higher trophic levels in glasshouse experiments, but evidence from field studies on the relevance of these multitrophic interactions for plant performance is lacking. Therefore, we examined whether PSF effects of several native and invasive plant species occur also in the field and influence plant damage by above-ground herbivores. Root zone soil from an abandoned urban field was used as inocula for the PSF experiment. First, we grew eight urban grassland plant species (five natives and three invasive species) separately in a glasshouse, with soil biota communities conditioned by the respective species itself (‘home soil’) or by a mixture of all other species (‘foreign soil’). After 1302weeks, one cohort of the plants was placed on an urban field in Berlin to assess damage by naturally colonizing herbivores, while another cohort of the plants stayed in the glasshouse. We observed that the extent of the PSF effects differed between the field and glasshouse cohorts of plants. While we found positive PSF responses for five of the eight plant species in the glasshouse, we found no PSF effects in the field. Further, there was no trend that invasive or native species differed in the direction or extent of PSF responses. Concerning the leaf damage by herbivores of the field plants, we found no evidence that the soil history (home vs. foreign soil) affected the effects of above-ground herbivores on the plants. Synthesis . We conclude that PSF effects are more likely to be found under glasshouse conditions. In the field, PSFs seem to play a minor role for the selected urban grassland species. More generally, our study highlights the need to focus on PSFs under natural conditions and in natural communities (including higher trophic levels), which is often overlooked in PSF research.
DOI:10.1016/j.soilbio.2015.07.017URL [本文引用: 2]
61Microstegium vimineum increases the abundance of ammonia-oxidizing archaea.61M. vimineum alters the community composition of ammonia oxidizers.61M. vimineum's impacts are seasonal, and have strong annual variation.61These impacts gradually declined when M. vimineum naturally declined at a site.61These impacts are therefore not likely to result in soil legacies.
DOI:10.1007/s11104-014-2151-4URL [本文引用: 2]
Background and aims Fine root decomposition contributes significantly to element cycling in terrestrial ecosystems. However, studies on root decomposition rates and on the factors that potentially...
DOI:10.1016/j.soilbio.2014.09.008URL [本文引用: 1]
61Soil biochemical parameters were deeply altered under Acacia dealbata invasion.61Decomposition processes could be accelerated in the presence of A.02dealbata.61Microbial community activity was generally increased in invaded soils.61Biochemical and microbial changes were more noticeable in the shrubland.61Phenological stage did not significantly affect soil microbial activity.
DOI:10.1111/j.1365-2486.2009.02042.xURL [本文引用: 1]
Invasive plant species affect a range of ecosystem processes but their impact on belowground carbon (C) pools is relatively unexplored. This is particularly true for grass invasions of forested ecosystems. Such invasions may alter both the quantity and quality of forest floor inputs. Dependent on both, two theories, 'priming' and 'preferential substrate utilization', suggest these changes may decrease, increase, or leave unchanged native plant-derived soil C. Decreases are expected under 'priming' theory due to increased soil microbial activity. Under 'preferential substrate utilization', either an increase or no change is expected because the invasive plant's inputs are used by the microbial community instead of soil C. Here, we examine how Microstegium vimineum affects belowground C-cycling in a southeastern US forest. Following predictions of priming theory, M. vimineum's presence is associated with decreases in native-derived, C pools. For example, in September 2006 M. vimineum is associated with 24%, 34%, 36%, and 72% declines in total organic, particulate organic matter, mineralizable (a measure of microbially-available C), and microbial biomass C, respectively. Soil C derived from M. vimineum does not compensate for these decreases, meaning that the sum of native- plus invasive-derived C pools is smaller than native-derived pools in uninvaded plots. Supporting our inferences that C-cycling accelerates under invasion, the microbial community is more active per unit biomass: added 13C-glucose is respired more rapidly in invaded plots. Our work suggests that this invader may accelerate C-cycling in forest soils and deplete C stocks. The paucity of studies investigating impacts of grass invasion on C-cycling in forests highlights the need to study further M. vimineum and other invasive grasses to assess their impacts on C sink strength and forest fertility.
DOI:10.1007/s11434-013-5955-3URL [本文引用: 1]
-N contents, whereas it significantly decreased the total N and soil organic matter contents. The available P content was significantly decreased by moderate invasion. The E. adenophorum invasion significantly decreased the biomass of total soil microbes, as well as Gram-negative bacteria, actinomycetes, arbuscular mycorrhizal (AM) fungi and non-AM fungi. However, E. adenophorum invasion significantly increased the activities of soil urease, acid phosphatase, polyphenol oxidase and peroxidase. Non-metric multidimensional scaling showed that soil microbial composition and soil enzyme composition were significantly different in the three E. adenophorum invaded sites. Partial Mantel tests indicated that plant composition was the most important factor for structuring soil microbial and enzyme compositions. The results suggest that changes in soil microbial community structure and enzyme activity may play an important role in the process of E. adenophorum invasion in a Chinese secondary forest ecosystem.
[本文引用: 1]
DOI:10.1111/j.1469-8137.2007.02207.xURLPMID:17822399 [本文引用: 1]
Summary 256 I. Introduction 257 II. Stages of invasion 260 III. A case for the four-stage framework: forecasting the response of nonindigenous plant species to climate change 268 IV. Conclusion 268 Acknowledgements 269 References 269 New Phytologist (2007) 176: 256090009273 0008 The Authors (2007). Journal compilation 0008 New Phytologist (2007)<BR> doi : 10.1111/j.1469-8137.2007.02207.x ABSTRACT Invasive nonindigenous plant species (NIPS) threaten native diversity, alter ecosystem processes, and may interact with other components of global environmental change. Here, a general framework is outlined that attempts to connect patterns of plant invasion to processes underlying these patterns at four well-established spatio-temporal stages of the invasion process: transport, colonization, establishment, and landscape spread. At each stage we organize findings and ideas about the filters that limit NIPS success and the interaction of these filters with historical aspects of introduction events, NIPS traits, and ecosystem properties. While it remains difficult to draw conclusions about the risk of invasion across ecosystems, to delineate universal 'invader traits', or to predict large-scale extinctions following invasions, this review highlights the growing body of research that suggests that the success of invasive NIPS is controlled by a series of key processes or filters. These filters are common to all invasion events, and will interact throughout the stages of plant invasion, although the relative importance of a filter may be stage, species or location specific. It is suggested that both research and management programs may benefit from employing multiscale and stage approaches to studying and controlling invasion. We further use the framework to briefly examine potential interactions between climate change and filters that limit NIPS invasion.
DOI:10.1111/j.1461-0248.2009.01418.xURLPMID:20002494 [本文引用: 2]
A major aim in ecology is identifying determinants of invasiveness. We performed a meta-analysis of 117 field or experimental-garden studies that measured pair-wise trait differences of a total of 125 invasive and 196 non-invasive plant species in the invasive range of the invasive species. We tested whether invasiveness is associated with performance-related traits (physiology, leaf-area allocation, shoot allocation, growth rate, size and fitness), and whether such associations depend on type of study and on biogeographical or biological factors. Overall, invasive species had significantly higher values than non-invasive species for all six trait categories. More trait differences were significant for invasive vs. native comparisons than for invasive vs. non-invasive alien comparisons. Moreover, for comparisons between invasive species and native species that themselves are invasive elsewhere, no trait differences were significant. Differences in physiology and growth rate were larger in tropical regions than in temperate regions. Trait differences did not depend on whether the invasive alien species originates from Europe, nor did they depend on the test environment. We conclude that invasive alien species had higher values for those traits related to performance than non-invasive species. This suggests that it might become possible to predict future plant invasions from species traits.
DOI:10.1111/j.1461-0248.2011.01628.xURLPMID:21592274 [本文引用: 1]
Abstract Biological invasions cause ecological and economic impacts across the globe. However, it is unclear whether there are strong patterns in terms of their major effects, how the vulnerability of different ecosystems varies and which ecosystem services are at greatest risk. We present a global meta-analysis of 199 articles reporting 1041 field studies that in total describe the impacts of 135 alien plant taxa on resident species, communities and ecosystems. Across studies, alien plants had a significant effect in 11 of 24 different types of impact assessed. The magnitude and direction of the impact varied both within and between different types of impact. On average, abundance and diversity of the resident species decreased in invaded sites, whereas primary production and several ecosystem processes were enhanced. While alien N-fixing species had greater impacts on N-cycling variables, they did not consistently affect other impact types. The magnitude of the impacts was not significantly different between island and mainland ecosystems. Overall, alien species impacts are heterogeneous and not unidirectional even within particular impact types. Our analysis also reveals that by the time changes in nutrient cycling are detected, major impacts on plant species and communities are likely to have already occurred. 2011 Blackwell Publishing Ltd/CNRS.
DOI:10.1023/A:1015798428743URL [本文引用: 1]
N limitation to primary production and other ecosystem processes is widespread. To understand the causes and distribution of N limitation, we must understand the controls of biological N fixation. The physiology of this process is reasonably well characterized, but our understanding of ecological controls is sparse, except in a few cultivated ecosystems. We review information on the ecological controls of N fixation in free-living cyanobacteria, vascular plant symbioses, and heterotrophic bacteria, with a view toward developing improved conceptual and simulation models of ecological controls of biological N fixation. A model (Howarth et al. 1999) of cyanobacterial fixation in lakes (where N fixation generally increases substantially when N:P ratios are low) versus estuaries (where planktonic N fixation is rare regardless of N:P ratios) concludes that an interaction of trace-element limitation and zooplankton grazing could constrain cyanobacteria in estuaries and so sustain N limitation. Similarly, a model of symbiotic N fixation on land (Vitousek & Field 1999) suggests that shade intolerance, P limitation, and grazing on N-rich plant tissues could suppress symbiotic N fixers in late-successional forest ecosystems. This congruence of results raises the question -- why do late-successional tropical forests often contain many potentially N-fixing canopy legumes, while N fixers are absent from most late-successional temperate and boreal forests? We suggest that relatively high N availability in lowland tropical forests permits legumes to maintain an N-demanding lifestyle (McKey 1994) without always being required to pay the costs of fixing N. Overall, both the few simulation models and the more-numerous conceptual models of ecological controls of biological N fixation suggest that there are substantial common features across N-fixing organisms and ecosystems. Despite the many groups of organisms capable of fixing N, and the very different ecosystems in which the process is important, we suggest that these common controls provide a foundation for the development of regional and global models that incorporate ecological controls of biological N fixation.
DOI:10.1126/science.225.4657.51URLPMID:17775660 [本文引用: 1]
Intensive forest management led to elevated losses of nitrogen from a recently harvested loblolly pine plantation in North Carolina. Measurements of nitrogen-15 retention in the field demonstrated that microbial uptake of nitrogen during the decomposition of residual organic material was the most important process retaining nitrogen. Management practices that remove this material cause increased losses of nitrogen to aquatic ecosystems and the atmosphere.
DOI:10.1016/j.soilbio.2005.09.009URL [本文引用: 1]
Intact soil cores from three adjacent sites (Site A: grazed, Site B: fenced for 4 years, and Site C: fenced for 24 years) were incubated in the laboratory to examine effects of temperature, soil moisture, and their interactions on net nitrification and N mineralization rates in the Inner Mongolia grassland of Northern China. Incubation temperature significantly influenced net nitrification and N mineralization rates in all the three grassland sites. There were no differences in net nitrification or N mineralization rates at lower temperatures ( 10, 0, and 5 C) whereas significant differences were found at higher temperatures (15, 25, and 35 C). Soil moisture profoundly impacted net nitrification and N mineralization rates in all the three sites. Interactions of temperature and moisture significantly affected net nitrification and mineralization rates in Site B and C, but not in Site A. Temperature sensitivity of net nitrification and N mineralization varied with soil moisture and grassland site. Our results showed greater net N mineralization rates and lower concentrations of inorganic N in the grazed site than those in the fenced sites, suggesting negative impacts of grazing on soil N pools and net primary productivity.
DOI:10.1007/s11356-016-8127-6URLPMID:27885581 [本文引用: 1]
Plant invasion has been reported to affect a mass of soil ecological processes and functions, although invasion effects are often context-, species- and ecosystem- specific. This study was conducted to explore potential impacts of Praxelis clematidea invasion on contents of total and available soil nitrogen (N) and microbial N transformations in a tropical savanna. Soil samples were collected from the surface and sub-surface layers in plots with non-, slight, or severe P. clematidea invasion in Hainan Province of southern China, which remains less studied, and analyzed for contents of the total and available N fractions and microbial N transformations. Results showed that total N content significantly increased in the surface soil but trended to decrease in the sub-surface soil in the invaded plots relative to the non-invaded control. Slight invasion significantly increased soil alkali-hydrolysable N content in the two soil layers. Soil net N mineralization rate was not significantly changed in both the soil layers, although soil microbial biomass N was significantly higher in plots with severe invasion than the control. There was no significant difference in content of soil N fractions between plots with slight and severe invasion. Our results suggest that invasion of P. clematidea promotes soil N accumulation in the surface soil layer, which is associated with increased microbial biomass N. However, the invasion-induced ecological impacts did not increase with further invasion. Significantly higher microbial biomass N was maintained in plots with severe invasion, implying that severe P. clematidea invasion may accelerate nutrient cycling in invaded ecosystems.
DOI:10.1007/s11104-014-2040-xURL [本文引用: 1]
<p class="FR_field">Successful invasion by exotic plant species can modify the abundance and composition of soil microbial communities. Eupatorium adenophora and Chromolaena odorata are exotics that have become highly invasive plants in China. Several studies have investigated mechanisms of their successful invasions including phenotypic plasticity, genetic differentiation, and allelopathy, but little is known about their effects on soil microorganisms. Moreover, whether soil microbial community changes could cause feedback effects on these plant species is also not known. We seek a belowground microbiological mechanism supporting successful invasions by these exotic plants.In this study, two invasive (E. adenophora and C. odorata) and two native plant species (Eupatorium japonicum and Eupatorium heterophyllum) were used to compare the soil feedback (on plant growth) before and after soil sterilization and from plant-root exudates. Bacterial and fungal biomass and community composition were also examined.We found that soil sterilization significantly increased biomass of native species and did not affect the invasive species' biomass. After root exudates from these plants had acted on the soil biota for 10 months, soil sterilization significantly decreased the growth of E. adenophora and C. odorata and continued to significantly increase the biomass of two native species. Denaturing gradient gel electrophoresis revealed that these four plant species modified fungal rather than bacterial communities in soil.Higher abundance of Paraglomus sp. in soil with C. odorata is likely to provide C. odorata roots with more soil nutrients. Considered together, these results strongly suggest that invasive E. adenophora and C. odorata created a belowground feedback that may be a mechanism contributing to their success as invasive species.
DOI:10.1016/j.apsoil.2011.10.021URL [本文引用: 2]
This study evaluated the soil characteristics and nitrogen-fixing bacterial (NFB) communities inhabiting the rhizosphere of an invasive plant, Ageratina adenophora, in Southwest of China. In a large geographic range, heavily invaded (HI) soils generally had higher nutrient levels compared with lightly invaded (LI) and non-invaded (NI) ones. The NFB number and species diversity of HI soils were significantly greater than those of NI ones. A total of 416 NFB isolates were divided into 47 operational taxonomic units (OTUs). They were phylogenetically categorized into Proteobacteria (63.9%), Actinobacteria (32.2%), Firmicutes (1.9%) and Bacteroidetes (1.9%). At a lower taxonomic level, these isolates were grouped into 20 genera, among which, the dominant isolates were Arthrobacter, Mitsuaria, Burkholderia, Sinorhizobium, Pseudomonas and Rhizobium. The phylogenetical structures of NFB communities obtained from HI, LI and NI soils were slightly different, with their phylogenetic structure similarity indices ( YC) being less than 0.8. However, the percentages of isolates represented by the shared species between any two communities were more than 80%, and in most cases, nearly 100%. There were 16 OTUs shared by these three communities (HI, NI and LI), representing 351 isolates (84.38% of total isolates). These facts indicated that numerically dominant species among HI, LI and NI soils were highly similar. In conclusion, A. adenophora invasion significantly increased the NFB number and diversity of soils, but did not change their phylogenetic structure of core community.
DOI:10.3724/SP.J.1143.2012.12025URL [本文引用: 1]
生物入侵是当今各国发展的一大挑战,特别是像中国这样的发展中国家。然而,我们对外来入侵种的本底资料还很不清楚,更缺乏相关的深入调查;对生物入侵所造成的生态和经济影响还没有引起足够的重视,同时也忽视了盲目引种可能带来的各种危害。本文在文献调研的基础上,从外来植物的入侵历史和文化、中国外来入侵植物的调查现状、外来植物入侵对生态安全及经济的影响等方面进行了全面系统的总结,并提出了中国外来入侵植物研究领域存在的问题及应对措施。
DOI:10.3724/SP.J.1143.2012.12025URL [本文引用: 1]
生物入侵是当今各国发展的一大挑战,特别是像中国这样的发展中国家。然而,我们对外来入侵种的本底资料还很不清楚,更缺乏相关的深入调查;对生物入侵所造成的生态和经济影响还没有引起足够的重视,同时也忽视了盲目引种可能带来的各种危害。本文在文献调研的基础上,从外来植物的入侵历史和文化、中国外来入侵植物的调查现状、外来植物入侵对生态安全及经济的影响等方面进行了全面系统的总结,并提出了中国外来入侵植物研究领域存在的问题及应对措施。
DOI:10.1016/j.soilbio.2017.06.010URL [本文引用: 3]
DOI:10.1016/j.apsoil.2017.02.003URL [本文引用: 1]
Growth and composition of plant communities depends on physico-chemical and biological characteristics of soils. Conversely, plants influence nutrient cycling and soil characteristics. Thus, they affect the long-term availability of nutrients, which feedbacks on their own growth and the primary productivity of ecosystems. This study focuses on the fertility and functioning of soils of a grazed savanna in Burkina Faso. It describes the effects of annual and perennial grasses involved in fallow succession, on chemical and biological (microbial biomass, mineralization and enzymatic activities) characteristics of soils. To do this, soil samples were collected under the four dominant species of grasses (A. ascinodis,A. gayanus,A. pseudapricusandL. togoensis) and under bare areas within 48 plots, as well as above- and belowground grass biomass. Results show that root biomass, pHKCl, basal respiration and fluorescein diacetate activities were significantly higher under perennial grasses (A. gayanusandA. ascinodis) than annual (A. pseudapricusandL. togoensis) and bare soil. Nitrate levels were higher underA. gayanusthat had the lowest root biomass. Total carbon, total nitrogen, microbial biomass and acid phosphatase were higher under the perennial grassA. ascinodis. pHwaterwas lower underA. pseudapricus. Finally, ammonium and -glucosidase activities weren significantly different between species. Overall, these results appear complex certainly due to factors of variability that remain to be identified. Nevertheless, they support the general hypothesis that perennial grasses have a greater influence on soil than annuals. Soil biological parameters (Basal respiration, microbial biomass, Beta-glucosidase, fluorescein-diacetate and acid phosphorus) exhibited strong relationship with soil pH, total C and N.
DOI:10.3321/j.issn:0023-074X.2005.09.011URL [本文引用: 1]
测定了紫茎泽兰(Eupatoriumadenophorum)重度入侵地土壤(对照于轻度入侵地土壤)的pH,有机质,N,P,K养分状况和细菌群落特征(BiologEcoPlateTM)的变化;并通过紫茎泽兰的水浸提液处理土壤,检测了紫茎泽兰对土壤细菌群落作用;然后通过盆栽实验研究了土壤性质的改变对外来植物紫茎泽兰入侵过程的意义.土壤性质分析结果表明,2个样地间的土壤pH,有机质,全N,全P和全K差异较小,而重度入侵地土壤的NH+4-N,NO3?-N和有效性P,K比轻度入侵地显著地提高,2个样地间的土壤细菌群落结构存在明显的差异;紫茎泽兰水浸提液处理的轻度入侵地土壤在细菌功能群结构上与原土壤存在较大差异,而与重度入侵地土壤具有很高的相似性.盆栽实验结果表明,当生长于重度入侵地土壤时,紫茎泽兰和三叶鬼针草的生长不受影响,但本地植物生长受到明显的抑制,在用活性炭除去土壤中可能残留的紫茎泽兰化感物质后,仍然表现出相同的规律.在以上结果中,土壤养分状况的差异无法解释生长于二种土壤上的本地植物生长的差异,而土壤细菌群落特征在样地间的变化与本地植物的生长表现出明显的相关性,暗示着改变土壤细菌群落可能是紫茎泽兰入侵过程的一个重要组成部分.土壤微生物群落可能在外来植物与本地植物的关系中起到了重要的“桥梁”的作用,外来植物可以
DOI:10.3321/j.issn:0023-074X.2005.09.011URL [本文引用: 1]
测定了紫茎泽兰(Eupatoriumadenophorum)重度入侵地土壤(对照于轻度入侵地土壤)的pH,有机质,N,P,K养分状况和细菌群落特征(BiologEcoPlateTM)的变化;并通过紫茎泽兰的水浸提液处理土壤,检测了紫茎泽兰对土壤细菌群落作用;然后通过盆栽实验研究了土壤性质的改变对外来植物紫茎泽兰入侵过程的意义.土壤性质分析结果表明,2个样地间的土壤pH,有机质,全N,全P和全K差异较小,而重度入侵地土壤的NH+4-N,NO3?-N和有效性P,K比轻度入侵地显著地提高,2个样地间的土壤细菌群落结构存在明显的差异;紫茎泽兰水浸提液处理的轻度入侵地土壤在细菌功能群结构上与原土壤存在较大差异,而与重度入侵地土壤具有很高的相似性.盆栽实验结果表明,当生长于重度入侵地土壤时,紫茎泽兰和三叶鬼针草的生长不受影响,但本地植物生长受到明显的抑制,在用活性炭除去土壤中可能残留的紫茎泽兰化感物质后,仍然表现出相同的规律.在以上结果中,土壤养分状况的差异无法解释生长于二种土壤上的本地植物生长的差异,而土壤细菌群落特征在样地间的变化与本地植物的生长表现出明显的相关性,暗示着改变土壤细菌群落可能是紫茎泽兰入侵过程的一个重要组成部分.土壤微生物群落可能在外来植物与本地植物的关系中起到了重要的“桥梁”的作用,外来植物可以
DOI:10.1016/j.soilbio.2010.06.006URL [本文引用: 1]
The exotic C 4 grass Spartina alterniflora was intentionally introduced to tidal coastal wetlands in Jiangsu province of China in 1982. Since then it has rapidly replaced the native C 3 plant Suaeda salsa, becoming one of the dominant vegetation types in the coastal wetlands of China. Although plant invasion can change soil organic carbon (SOC) storage, little is known about how plant invasion influences C storage within soil fractions. We investigated how S. alterniflora invasion across an 8, 12 and 14-year chronosequence affected SOC and soil nitrogen (N), using soil fractionation and stable δ 13C isotope analyses. SOC and N concentrations at 0–1002cm depth in S. alterniflora soil increased during the S. alterniflora invasion chronosequence, ranging from 3.67 to 4.9002g02C02kg 611 soil, and from 0.307 to 0.39102g02N02kg 611 soil. These were significantly higher than the values in the Suaeda salsa community, by 27.0–69.6% for SOC, and 21.8–55.2% for total N. The S. alterniflora-derived SOC varied from 0.40 to 0.9202g02C02kg 611 according to mixing calculations, assuming the two possible SOC sources of S. alterniflora and S. salsa, and accounted for 10.8–18.7% of total SOC in the colonized soils. The estimated accumulative rate of SOC from C 4 ( S.02alterniflora) was 64.102C02kg 61102soil year 611 and from C 3 sources was 78.102mg02C02kg 611. The concentration of S. alterniflora-derived SOC significantly decreased from coarse fraction to fine fraction, and linearly increased as the period of S. alterniflora invasion increased. The highest accumulative rate of SOC from02a02C 4 source occurred in macroaggregates, while the highest rate from C 3 was in microaggregates. The storage of SOC derived from S. alterniflora in the macroaggregates was 0.27–0.4402g02C02kg 611 soil, accounting for 43.1–49.1% of the total C 4derived SOC in the soil. Our results suggest that S. alterniflora invasion in coastal wetlands could facilitate SOC storage, because of the high potential for accumulation of the C which has been newly derived from S. alterniflora litter and roots.
DOI:10.1111/ele.13090URL [本文引用: 1]
There are often more invasive species in communities that are less phylogenetically diverse or distantly related to the invaders. This is thought to indicate reduced biotic resistance, but recent theory predicts that phylogenetic relationships have more influence on competitive outcomes when interactions are more pair-wise than diffuse. Therefore, phylogenetic relationships should change when... [Show full abstract]
Elevated enzyme activities in soils under the invasive nitrogen-fixing tree Falcataria moluccana
1
2006
... 探讨不同固氮功能和生活型入侵植物影响土壤氮有效性的差异有助于更好地理解不同外来植物入侵能力的差异性和土壤氮循环对植物入侵的反馈机制(
Changes in intrasystem N cycling from N2-fixing shrub encroachment in grassland: Multiple positive feedbacks
3
2006
... 探讨不同固氮功能和生活型入侵植物影响土壤氮有效性的差异有助于更好地理解不同外来植物入侵能力的差异性和土壤氮循环对植物入侵的反馈机制(
... ;
... 当前, 在入侵生态学和生物地球化学研究中, 探讨入侵植物功能特征与其对土壤氮循环影响幅度之间详细关系的研究还非常稀少, 其机制也亟待研究(
The increasing importance of distinguishing among plant nitrogen sources
2
2015
... 入侵区域土壤的无机氮含量范围为1.9-143.1 mg·kg-1, 平均值为(19.3 ± 3.7) mg·kg-1 (
... 当前, 在入侵生态学和生物地球化学研究中, 探讨入侵植物功能特征与其对土壤氮循环影响幅度之间详细关系的研究还非常稀少, 其机制也亟待研究(
Inorganic N turnover and availability in annual- and perennial-dominated soils in a northern Utah shrub-steppe ecosystem
1
2003
... 由于氮是植物生存生长重要的限制性资源, 因此入侵植物如何影响土壤氮有效性是理解其入侵机制的重要研究内容(
Belowground competition drives invasive plant impact on native species regardless of nitrogen availability
1
2017
... 根据整合的数据, 入侵区域土壤的总氮含量范围为0.0%-2.7%, 平均值为(0.4 ± 0.0)% (
Effects of invasive scotch broom on soil properties in a Pacific coastal praire soil
1
2006
... 根据整合的数据, 入侵区域土壤的总氮含量范围为0.0%-2.7%, 平均值为(0.4 ± 0.0)% (
Nitrogen losses from the soil-plant system: A review
1
2012
... 入侵区域土壤的无机氮含量范围为1.9-143.1 mg·kg-1, 平均值为(19.3 ± 3.7) mg·kg-1 (
What explains variation in the impacts of exotic plant invasions on the nitrogen cycle? A meta-analysis
2
2014
... 对这些方面的研究结果和证据进行整合分析有助于揭示植物入侵对土壤氮有效性影响的普遍规律和机制(
... 入侵区域土壤的无机氮含量范围为1.9-143.1 mg·kg-1, 平均值为(19.3 ± 3.7) mg·kg-1 (
Principles of Terrestrial Ecosystem Ecology.
1
2011
... 一年生草本、多年生草本、落叶灌木、常绿灌木、落叶乔木、常绿乔木植物入侵区域相对于无入侵区域土壤铵态氮含量的RV值分别为(8.1 ± 13.8)%、(32.7 ± 16.4)%、(1.0 ± 19.5)%、(14.2 ± 13.1)%、(26.6 ± 19.0)%、(275.6 ± 125.2)% (
Plants actively control nitrogen cycling: Uncorking the microbial bottleneck
1
2006
... 一年生草本、多年生草本、落叶灌木、常绿灌木、落叶乔木、常绿乔木植物入侵区域相对于无入侵区域土壤铵态氮含量的RV值分别为(8.1 ± 13.8)%、(32.7 ± 16.4)%、(1.0 ± 19.5)%、(14.2 ± 13.1)%、(26.6 ± 19.0)%、(275.6 ± 125.2)% (
Effects of the invasive plant Mikania micrantha H.B.K. on soil nitrogen availability through allelopathy in South China
1
2009
... 由于氮是植物生存生长重要的限制性资源, 因此入侵植物如何影响土壤氮有效性是理解其入侵机制的重要研究内容(
Patterns in understory woody diversity and soil nitrogen across native- and non-native- urban tropical forests
1
2014
... 由于氮是植物生存生长重要的限制性资源, 因此入侵植物如何影响土壤氮有效性是理解其入侵机制的重要研究内容(
Niche construction by the invasive Asian knotweeds (species complex Fallopia): Impact on activity, abundance and community structure of denitrifiers and nitrifiers
1
2011
... 入侵区域土壤的无机氮含量范围为1.9-143.1 mg·kg-1, 平均值为(19.3 ± 3.7) mg·kg-1 (
China’s booming economy is sparking and accelerating biological invasions
1
2008
... 外来植物入侵指在人为或自然因素作用下, 植物由原产地进入新栖息地存活、繁殖、建群、扩张, 并造成明显的生态或经济影响的现象(
Influence of leaf phenology and site nitrogen on invasive species establishment in temperate deciduous forest understories
1
2013
... 由于氮是植物生存生长重要的限制性资源, 因此入侵植物如何影响土壤氮有效性是理解其入侵机制的重要研究内容(
Effects of exotic plant invasions on soil nutrient cycling processes
1
2003
... 由于氮是植物生存生长重要的限制性资源, 因此入侵植物如何影响土壤氮有效性是理解其入侵机制的重要研究内容(
Evolutionary tradeoffs for nitrogen allocation to photosynthesis versus cell walls in an invasive plant
1
2009
... 由于氮是植物生存生长重要的限制性资源, 因此入侵植物如何影响土壤氮有效性是理解其入侵机制的重要研究内容(
Nitrogen cycles: Past, present, and future
1
2004
... 探讨不同固氮功能和生活型入侵植物影响土壤氮有效性的差异有助于更好地理解不同外来植物入侵能力的差异性和土壤氮循环对植物入侵的反馈机制(
Multispecies comparison reveals that invasive and native plants differ in their traits but not in their plasticity
1
2011
... 根据整合的数据, 入侵区域土壤的总氮含量范围为0.0%-2.7%, 平均值为(0.4 ± 0.0)% (
Invasion of alien Acacia dealbata on Spanish Quercus robur forests: Impact on soils and vegetation
2
2012
... 根据整合的数据, 入侵区域土壤的总氮含量范围为0.0%-2.7%, 平均值为(0.4 ± 0.0)% (
... 入侵区域土壤的无机氮含量范围为1.9-143.1 mg·kg-1, 平均值为(19.3 ± 3.7) mg·kg-1 (
Meta-analysis and the science of research synthesis
1
2018
... 对这些方面的研究结果和证据进行整合分析有助于揭示植物入侵对土壤氮有效性影响的普遍规律和机制(
Plant invasion alters nitrogen cycling by modifying the soil nitrifying community
1
2005
... 由于氮是植物生存生长重要的限制性资源, 因此入侵植物如何影响土壤氮有效性是理解其入侵机制的重要研究内容(
Plant nitrogen and phosphorus utilization under invasive pressure in a montane ecosystem of tropical China
2
2018
... 由于氮是植物生存生长重要的限制性资源, 因此入侵植物如何影响土壤氮有效性是理解其入侵机制的重要研究内容(
... 温带、亚热带、热带地区植物入侵区域相对于无入侵区域土壤铵态氮含量的RV值分别为(70.5 ± 42.9)%、(57.4 ± 24.6)%、(11.5 ± 11.6)% (
Litter species traits, but not richness, contribute to carbon and nitrogen dynamics in an alpine meadow on the Tibetan Plateau
1
2013
... 一年生草本、多年生草本、落叶灌木、常绿灌木、落叶乔木、常绿乔木植物入侵区域相对于无入侵区域土壤铵态氮含量的RV值分别为(8.1 ± 13.8)%、(32.7 ± 16.4)%、(1.0 ± 19.5)%、(14.2 ± 13.1)%、(26.6 ± 19.0)%、(275.6 ± 125.2)% (
Herbaceous plant species invading natural areas tend to have stronger adaptive root foraging than other naturalized species
1
2015
... 入侵区域土壤的无机氮含量范围为1.9-143.1 mg·kg-1, 平均值为(19.3 ± 3.7) mg·kg-1 (
Mechanisms of plant species impacts on ecosystem nitrogen cycling
1
2002
... 一年生草本、多年生草本、落叶灌木、常绿灌木、落叶乔木、常绿乔木植物入侵区域相对于无入侵区域土壤铵态氮含量的RV值分别为(8.1 ± 13.8)%、(32.7 ± 16.4)%、(1.0 ± 19.5)%、(14.2 ± 13.1)%、(26.6 ± 19.0)%、(275.6 ± 125.2)% (
Differences in earthworm densities and nitrogen dynamics in soils under exotic and native plant species
1
1999
... 入侵区域土壤的无机氮含量范围为1.9-143.1 mg·kg-1, 平均值为(19.3 ± 3.7) mg·kg-1 (
Invasive species’ leaf traits and dissimilarity from natives shape their impact on nitrogen cycling: A meta-analysis
1
2016
... 由于氮是植物生存生长重要的限制性资源, 因此入侵植物如何影响土壤氮有效性是理解其入侵机制的重要研究内容(
外来植物入侵对生物多样性的影响及本地生物的进化响应
1
2010
... 外来植物入侵指在人为或自然因素作用下, 植物由原产地进入新栖息地存活、繁殖、建群、扩张, 并造成明显的生态或经济影响的现象(
外来植物入侵对生物多样性的影响及本地生物的进化响应
1
2010
... 外来植物入侵指在人为或自然因素作用下, 植物由原产地进入新栖息地存活、繁殖、建群、扩张, 并造成明显的生态或经济影响的现象(
生物入侵: 中国****面临的转化生态学机遇与挑战
1
2010
... 外来植物入侵指在人为或自然因素作用下, 植物由原产地进入新栖息地存活、繁殖、建群、扩张, 并造成明显的生态或经济影响的现象(
生物入侵: 中国****面临的转化生态学机遇与挑战
1
2010
... 外来植物入侵指在人为或自然因素作用下, 植物由原产地进入新栖息地存活、繁殖、建群、扩张, 并造成明显的生态或经济影响的现象(
Relationship between Mikania micrantha invasion and soil microbial biomass, respiration and functional diversity
2
2007
... 根据整合的数据, 入侵区域土壤的总氮含量范围为0.0%-2.7%, 平均值为(0.4 ± 0.0)% (
... ), 氮固持能力的增加一定程度上减少了土壤氮淋溶丢失(
Altered ecosystem carbon and nitrogen cycles by plant invasion: A meta-analysis
9
2008
... 由于氮是植物生存生长重要的限制性资源, 因此入侵植物如何影响土壤氮有效性是理解其入侵机制的重要研究内容(
... )存在不同程度的差异, 为植物入侵可改变土壤氮有效性的观点提供了充足证据(
... 对这些方面的研究结果和证据进行整合分析有助于揭示植物入侵对土壤氮有效性影响的普遍规律和机制(
... ).不同气候带的入侵地点以及不同生活型和固氮功能的入侵植物存在生物学特性和入侵地非生物因素等方面的异质性(
... 其中, CI和CN分别为入侵区域土壤和无入侵区域土壤相同氮指标的值.参考
... 入侵区域土壤的无机氮含量范围为1.9-143.1 mg·kg-1, 平均值为(19.3 ± 3.7) mg·kg-1 (
... ).主要原因是入侵后土壤矿化作用的增强产生足够的铵态氮(
... 不同生活型的入侵植物存在光合、生长速率、氮吸收能力和策略等诸多功能性状差异(
... 当前, 在入侵生态学和生物地球化学研究中, 探讨入侵植物功能特征与其对土壤氮循环影响幅度之间详细关系的研究还非常稀少, 其机制也亟待研究(
Organic matter turnover in soil physical fractions following woody plant invasion of grassland: Evidence from natural 13C and 15N
2
2006
... 不同生活型的入侵植物存在光合、生长速率、氮吸收能力和策略等诸多功能性状差异(
... 一年生草本、多年生草本、落叶灌木、常绿灌木、落叶乔木、常绿乔木植物入侵区域相对于无入侵区域土壤铵态氮含量的RV值分别为(8.1 ± 13.8)%、(32.7 ± 16.4)%、(1.0 ± 19.5)%、(14.2 ± 13.1)%、(26.6 ± 19.0)%、(275.6 ± 125.2)% (
Contributions of ammonia-oxidizing archaea and bacteria to nitrification in Oregon forest soils
1
2015
... 当前, 在入侵生态学和生物地球化学研究中, 探讨入侵植物功能特征与其对土壤氮循环影响幅度之间详细关系的研究还非常稀少, 其机制也亟待研究(
Short- and long-term impacts of Acacia longifolia invasion on the belowground processes of a Mediterranean coastal dune ecosystem
1
2008
... 入侵区域土壤的无机氮含量范围为1.9-143.1 mg·kg-1, 平均值为(19.3 ± 3.7) mg·kg-1 (
Nitrogen stable isotopic composition of leaves and soil: Tropical versus temperate forests
2
1999
... 温带、亚热带、热带地区植物入侵区域相对于无入侵区域土壤铵态氮含量的RV值分别为(70.5 ± 42.9)%、(57.4 ± 24.6)%、(11.5 ± 11.6)% (
... 、3G).相对而言, 温带地区较低的气温和降水量条件使得生态系统土壤无机氮水平通常较低且植物生长处于氮限制状态(
Exotic invasive plants increase productivity, abundance of ammonia-oxidizing bacteria and nitrogen availability in intermountain grasslands
3
2016
... 由于氮是植物生存生长重要的限制性资源, 因此入侵植物如何影响土壤氮有效性是理解其入侵机制的重要研究内容(
... 入侵区域土壤的无机氮含量范围为1.9-143.1 mg·kg-1, 平均值为(19.3 ± 3.7) mg·kg-1 (
... ).甚至, 研究发现入侵植物净初级生产力与原位土壤硝态氮水平存在显著正相关性(
Disentangling invasiveness and invasibility during invasion in synthesized grassland communities
2
2003
... 对这些方面的研究结果和证据进行整合分析有助于揭示植物入侵对土壤氮有效性影响的普遍规律和机制(
... 除了外来植物的入侵能力, 入侵地点的环境可入侵性(如土壤氮有效性水平)也是决定入侵程度和扩张速度的重要原因(
An invasive aster (Ageratina adenophora) invades and dominates forest understories in China: Altered soil microbial communities facilitate the invader and inhibit natives
1
2007
... 由于氮是植物生存生长重要的限制性资源, 因此入侵植物如何影响土壤氮有效性是理解其入侵机制的重要研究内容(
Plant-soil feedback as a mechanism of invasion by Carpobrotus edulis
1
2010
... 探讨不同固氮功能和生活型入侵植物影响土壤氮有效性的差异有助于更好地理解不同外来植物入侵能力的差异性和土壤氮循环对植物入侵的反馈机制(
N2-fixing red alder indirectly accelerates ecosystem nitrogen cycling
1
2014
... 探讨不同固氮功能和生活型入侵植物影响土壤氮有效性的差异有助于更好地理解不同外来植物入侵能力的差异性和土壤氮循环对植物入侵的反馈机制(
Update on the environmental and economic costs associated with alien- invasive species in the United States
1
2005
... 外来植物入侵指在人为或自然因素作用下, 植物由原产地进入新栖息地存活、繁殖、建群、扩张, 并造成明显的生态或经济影响的现象(
Impact of deciduous tree species on litterfall quality, decomposition rates and nutrient circulation in pine stands
2
2008
... 不同生活型的入侵植物存在光合、生长速率、氮吸收能力和策略等诸多功能性状差异(
... 一年生草本、多年生草本、落叶灌木、常绿灌木、落叶乔木、常绿乔木植物入侵区域相对于无入侵区域土壤铵态氮含量的RV值分别为(8.1 ± 13.8)%、(32.7 ± 16.4)%、(1.0 ± 19.5)%、(14.2 ± 13.1)%、(26.6 ± 19.0)%、(275.6 ± 125.2)% (
Global patterns of plant leaf N and P in relation to temperature and latitude
1
2004
... 除了外来植物的入侵能力, 入侵地点的环境可入侵性(如土壤氮有效性水平)也是决定入侵程度和扩张速度的重要原因(
Invasive Andropogon gayanus(gamba grass) is an ecosystem transformer of nitrogen relations in Australian savanna
2
2009
... 由于氮是植物生存生长重要的限制性资源, 因此入侵植物如何影响土壤氮有效性是理解其入侵机制的重要研究内容(
... 入侵区域土壤的无机氮含量范围为1.9-143.1 mg·kg-1, 平均值为(19.3 ± 3.7) mg·kg-1 (
Plant invasion is associated with higher plant-soil nutrient concentrations in nutrient-poor environments
2
2016
... 由于氮是植物生存生长重要的限制性资源, 因此入侵植物如何影响土壤氮有效性是理解其入侵机制的重要研究内容(
... 温带、亚热带、热带地区植物入侵区域相对于无入侵区域土壤铵态氮含量的RV值分别为(70.5 ± 42.9)%、(57.4 ± 24.6)%、(11.5 ± 11.6)% (
No evidence that plant-soil feedback effects of native and invasive plant species under glasshouse conditions are reflected in the field
1
2016
... 对这些方面的研究结果和证据进行整合分析有助于揭示植物入侵对土壤氮有效性影响的普遍规律和机制(
The role of ammonium oxidizing communities in mediating effects of an invasive plant on soil nitrification
2
2015
... 入侵区域土壤的无机氮含量范围为1.9-143.1 mg·kg-1, 平均值为(19.3 ± 3.7) mg·kg-1 (
... 当前, 在入侵生态学和生物地球化学研究中, 探讨入侵植物功能特征与其对土壤氮循环影响幅度之间详细关系的研究还非常稀少, 其机制也亟待研究(
Factors controlling decomposition rates of fine root litter in temperate forests and grasslands
2
2014
... 不同生活型的入侵植物存在光合、生长速率、氮吸收能力和策略等诸多功能性状差异(
... 一年生草本、多年生草本、落叶灌木、常绿灌木、落叶乔木、常绿乔木植物入侵区域相对于无入侵区域土壤铵态氮含量的RV值分别为(8.1 ± 13.8)%、(32.7 ± 16.4)%、(1.0 ± 19.5)%、(14.2 ± 13.1)%、(26.6 ± 19.0)%、(275.6 ± 125.2)% (
Soil biochemical alterations and microbial community responses under Acacia dealbata Link invasion
1
2014
... 入侵区域土壤的无机氮含量范围为1.9-143.1 mg·kg-1, 平均值为(19.3 ± 3.7) mg·kg-1 (
Grass invasion of a hardwood forest is associated with declines in belowground carbon pools
1
2010
... 入侵区域土壤的无机氮含量范围为1.9-143.1 mg·kg-1, 平均值为(19.3 ± 3.7) mg·kg-1 (
Changes in soil microbial community and enzyme activity along an exotic plant Eupatorium adenophorum invasion in a Chinese secondary forest
1
2013
... 入侵区域土壤的无机氮含量范围为1.9-143.1 mg·kg-1, 平均值为(19.3 ± 3.7) mg·kg-1 (
Changes in nitrogen-cycling microbial communities with depth in temperate and subtropical forest soils
1
2017
... 温带、亚热带、热带地区植物入侵区域相对于无入侵区域土壤铵态氮含量的RV值分别为(70.5 ± 42.9)%、(57.4 ± 24.6)%、(11.5 ± 11.6)% (
Plant invasion across space and time: Factors affecting nonindigenous species success during four stages of invasion
1
2007
... 外来植物入侵指在人为或自然因素作用下, 植物由原产地进入新栖息地存活、繁殖、建群、扩张, 并造成明显的生态或经济影响的现象(
A meta-analysis of trait differences between invasive and non-invasive plant species
2
2010
... 根据整合的数据, 入侵区域土壤的总氮含量范围为0.0%-2.7%, 平均值为(0.4 ± 0.0)% (
... 除了外来植物的入侵能力, 入侵地点的环境可入侵性(如土壤氮有效性水平)也是决定入侵程度和扩张速度的重要原因(
Ecological impacts of invasive alien plants: A meta-analysis of their effects on species, communities and ecosystems
1
2011
... 对这些方面的研究结果和证据进行整合分析有助于揭示植物入侵对土壤氮有效性影响的普遍规律和机制(
Towards an ecological understanding of biological nitrogen fixation
1
2002
... 探讨不同固氮功能和生活型入侵植物影响土壤氮有效性的差异有助于更好地理解不同外来植物入侵能力的差异性和土壤氮循环对植物入侵的反馈机制(
Mechanisms of nitrogen retention in forest ecosystems: A field experiment
1
1984
... 一年生草本、多年生草本、落叶灌木、常绿灌木、落叶乔木、常绿乔木植物入侵区域相对于无入侵区域土壤铵态氮含量的RV值分别为(8.1 ± 13.8)%、(32.7 ± 16.4)%、(1.0 ± 19.5)%、(14.2 ± 13.1)%、(26.6 ± 19.0)%、(275.6 ± 125.2)% (
Temperature and soil moisture interactively affected soil net N mineralization in temperate grassland in Northern China
1
2006
... 除了外来植物的入侵能力, 入侵地点的环境可入侵性(如土壤氮有效性水平)也是决定入侵程度和扩张速度的重要原因(
Effects of Praxelis clematidea invasion on soil nitrogen fractions and transformation rates in a tropical savanna
1
2017
... 根据整合的数据, 入侵区域土壤的总氮含量范围为0.0%-2.7%, 平均值为(0.4 ± 0.0)% (
Soil fungi rather than bacteria were modified by invasive plants, and that benefited invasive plant growth
1
2014
... 由于氮是植物生存生长重要的限制性资源, 因此入侵植物如何影响土壤氮有效性是理解其入侵机制的重要研究内容(
Changes in non-symbiotic nitrogen-fixing bacteria inhabiting rhizosphere soils of an invasive plant Ageratina adenophora
2
2012
... 根据整合的数据, 入侵区域土壤的总氮含量范围为0.0%-2.7%, 平均值为(0.4 ± 0.0)% (
... 入侵区域土壤的无机氮含量范围为1.9-143.1 mg·kg-1, 平均值为(19.3 ± 3.7) mg·kg-1 (
中国外来入侵植物研究现状及存在的问题
1
2012
... 外来植物入侵指在人为或自然因素作用下, 植物由原产地进入新栖息地存活、繁殖、建群、扩张, 并造成明显的生态或经济影响的现象(
中国外来入侵植物研究现状及存在的问题
1
2012
... 外来植物入侵指在人为或自然因素作用下, 植物由原产地进入新栖息地存活、繁殖、建群、扩张, 并造成明显的生态或经济影响的现象(
Ammonium availability and temperature control contributions of ammonia oxidizing bacteria and archaea to nitrification in an agricultural soil
3
2017
... 入侵区域土壤的无机氮含量范围为1.9-143.1 mg·kg-1, 平均值为(19.3 ± 3.7) mg·kg-1 (
... 一年生草本、多年生草本、落叶灌木、常绿灌木、落叶乔木、常绿乔木植物入侵区域相对于无入侵区域土壤铵态氮含量的RV值分别为(8.1 ± 13.8)%、(32.7 ± 16.4)%、(1.0 ± 19.5)%、(14.2 ± 13.1)%、(26.6 ± 19.0)%、(275.6 ± 125.2)% (
... 当前, 在入侵生态学和生物地球化学研究中, 探讨入侵植物功能特征与其对土壤氮循环影响幅度之间详细关系的研究还非常稀少, 其机制也亟待研究(
Contrasted effects of annual and perennial grasses on soil chemical and biological characteristics of a grazed Sudanian savanna
1
2017
... 不同生活型的入侵植物存在光合、生长速率、氮吸收能力和策略等诸多功能性状差异(
一个可能的植物入侵机制: 入侵种通过改变入侵地土壤微生物群落影响本地种的生长
1
2005
... 由于氮是植物生存生长重要的限制性资源, 因此入侵植物如何影响土壤氮有效性是理解其入侵机制的重要研究内容(
一个可能的植物入侵机制: 入侵种通过改变入侵地土壤微生物群落影响本地种的生长
1
2005
... 由于氮是植物生存生长重要的限制性资源, 因此入侵植物如何影响土壤氮有效性是理解其入侵机制的重要研究内容(
Changes in soil organic carbon dynamics in an eastern Chinese coastal wetland following invasion by a C4 plant Spartina alterniflora
1
2010
... 根据整合的数据, 入侵区域土壤的总氮含量范围为0.0%-2.7%, 平均值为(0.4 ± 0.0)% (
Species composition, functional and phylogenetic distances correlate with success of invasive Chromolaena odorata in an experimental test
1
2018
... 外来植物入侵指在人为或自然因素作用下, 植物由原产地进入新栖息地存活、繁殖、建群、扩张, 并造成明显的生态或经济影响的现象(
