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竹林扩张符合外来物种入侵范式吗?——从养分循环角度初探
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作者 李丝雨 栾军伟 《世界竹藤通讯》 2020年第6期64-68,共5页
凋落物分解是生态系统中碳和养分循环的基础,有关植物入侵对凋落物分解的影响通常通过叶片凋落物性状差异来预测,并且普遍认为外来入侵植物分解更快,并籍以促进入侵地养分循环从而有利于其进一步入侵。然而,植物入侵还可能影响分解者的... 凋落物分解是生态系统中碳和养分循环的基础,有关植物入侵对凋落物分解的影响通常通过叶片凋落物性状差异来预测,并且普遍认为外来入侵植物分解更快,并籍以促进入侵地养分循环从而有利于其进一步入侵。然而,植物入侵还可能影响分解者的活性或改变分解者的功能多样性,从而改变凋落物分解,其机制尚不清楚;而且在不同的气候条件下其影响可能会有所不同。毛竹由于其克隆生长的特性,在缺乏管理的情况下往往会向邻近森林群落扩张,其对生态系统的负面影响近年来广受诟病。不过,其对生态系统影响是否符合外来入侵植物生态范式仍值得商榷。本研究在全国范围内存在毛竹扩张的7个地区建立84个观测样地,通过在受侵和未受侵群落开展凋落物分解实验研究,同时考虑了土壤分解者功能群的贡献及凋落物混合效应。研究结果表明,随着土壤分解者功能群多样性的增加,尤其是大型土壤动物的存在,凋落物碳和氮的循环以及分解的气候敏感性均相应增加,但分解者的氮利用效率降低。凋落物混合效应加速其分解(9.5%)和氮素循环(28.9%),但不依赖于分解者功能多样性。相反,被毛竹入侵的样地分解速度减缓,分解者氮利用效率降低,但在排除了大型土壤动物的作用后,这种负效应则被逆转,毛竹入侵降低了分解者尤其是大型土壤动物的气候敏感性。上述结果表明,分解者的功能多样性能够调节并在很大程度上决定凋落物分解受植物入侵的影响。同时,上述现象不完全符合外来入侵物种的“养分促进”假说,意味着毛竹扩张从凋落物分解层面或许难以像外来入侵物种那样形成正反馈。在当前和未来气候条件下,将分解者功能群(尤其是大型土壤动物)及其与凋落物性状的交互效应纳入相关模型,与以往基于植物功能性状的框架相比,有利于更加可靠的预测植物入侵对生态系统功能的改变。 展开更多
关键词 碳循环 生态系统过程 入侵 养分循环 凋落物混合效应 -土壤相互作用 土壤动
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Characteristics of fungal community structure during the decomposition of mixed foliage litter from Pinus massoniana and broadleaved tree species in southwestern China 被引量:6
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作者 Yan Zhang Xun Li +4 位作者 Danju Zhang Yu Qin Yang Zhou Simeng Song Jian Zhang 《Journal of Plant Ecology》 SCIE CSCD 2020年第5期574-588,共15页
Aims The conifer litter is fairly recalcitrant and nutrient poor,and broadleaved litter promotes coniferous litter decomposition by increasing degradable nutrients and promoting microbial metabolism.Mixing Pinus masso... Aims The conifer litter is fairly recalcitrant and nutrient poor,and broadleaved litter promotes coniferous litter decomposition by increasing degradable nutrients and promoting microbial metabolism.Mixing Pinus massoniana litter and three broadleaved litters may increase the diversity and abundance of fungal decomposers compared with those in P.massoniana litter and vary depending on the number and proportion of broadleaved species included.Methods We analysed the composition and diversity of fungal communities during mixed litter decomposition in southwestern China with 35 treatments(P.massoniana,Toona sinensis,Cinnamomum camphora and Sassafras tzumu litter)using Illumina high-throughput sequencing.Important Findings The mixed litters increased fungal diversity and richness compared with those in the single-species litter,except in the following treatments:P.massoniana litter accounting for 70%-80%in the P.massoniana+T.sinensis,P.massoniana+S.tzumu+T.sinensis and P.massoniana+S.tzumu+C.camphora combinations,and P.massoniana+S.tzumu+C.camphora+T.sinensis combination with small proportion of T.sinensis litter.The diversity and richness of the 7:1:2 combination of P.massoniana+C.camphora+T.sinensis were significantly higher than those in the other treatments.Ascomycota and Basidiomycota were the dominant phyla,and Aspergillus was the most abundant genus.The decomposition of litters from one needleleaf and one broadleaved species(6:4)and one needleleaf species and two broadleaved species(broadleaved litter accounting for 30%-40%)exhibited synergistic interactions throughout the decomposition process,and the relative abundance of fungi that decompose refractory substances increased.The P.massoniana+C.camphora+T.sinensis combination and a 30%-40%broadleaf litter proportion increased fungal diversity and accelerated the decomposition of recalcitrant coniferous litter.Therefore,C.camphora and T.sinensis are a potential candidate species for mixed planting with P.massoniana. 展开更多
关键词 fungal community mixed leaf litter non-additive effect Pinus massoniana high-throughput sequencing
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