Knowledge Resource Center for Ecological Environment in Arid Area
| 沙地人工林下生物土壤结皮对土壤微食物网的影响 | |
| 其他题名 | The effects of biological soil crust on soil micro-food web under sand-binding vegetation in sandy land |
| 管平婷 | |
| 出版年 | 2018 |
| 学位类型 | 博士 |
| 导师 | 梁文举 ; 张晓珂 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 生物土壤结皮作为沙漠生态系统的重要组成部分，在维持沙漠化生态系统的稳定性和生态恢复中发挥着重要作用。目前，关于生物土壤结皮如何影响沙漠地下生态系统的研究还十分匮乏。本研究以科尔沁沙地生态系统为研究对象，开展了不同生长年限人工林下生物土壤结皮对土壤微食物网影响的研究，同时讨论了不同环境条件生物土壤结皮下微食物网的变化。研究结果表明：1. 随着人工林生长年限的增加，结皮从藻-地衣结皮向苔藓结皮发育；结皮中的有机碳、全氮和pH含量随之增加。人工林生长29年后，土壤有机碳、全氮、pH值、土壤微生物磷脂脂肪酸含量和土壤线虫多度显著增加。土壤微生物群落结构变化主要受土壤有机碳和全氮的影响；土壤线虫群落结构变化主要受土壤有机碳、全氮含量和pH值的影响。由于不同的土壤微生物群落和土壤线虫属组成对栖息地适应程度不同，从而对人工林不同生长年限的响应也不同，因此，它们的变化可以指示人工林栽植后沙地生态系统的恢复程度。2.与无生物土壤结皮覆盖的表层土壤相比较，生物土壤结皮层的有机碳、全氮和电导率更高，但它的存在并没有显著改变其下土壤的碳氮含量。相比于无结皮覆盖的土壤，生物土壤结皮下土壤微食物网中微生物磷脂脂肪酸含量和生物量碳以及线虫的多度、生物量碳和代谢活性也更高，生物土壤结皮对土壤微食物网的影响主要集中在0–5 cm的表层土壤中。生物土壤结皮自身固定的碳提高了对土壤微食物网中真菌通路和捕食-杂食通路中碳流的输入量，同时也增加了真菌通路和捕食-杂食通路的联通性。因此，生物土壤结皮的存在有利于土壤微食物网向更复杂、更网状化的结构发展，进而提高了沙地土壤生态系统的稳定性。3.温度和水分变化培养试验研究结果表明，温度变化对生物土壤结皮下的土壤微生物和土壤线虫无显著影响；生物土壤结皮下土壤微生物和线虫群落对水分变化响应有所不同，干旱环境（20%田间持水量）土壤微生物群落磷脂脂肪酸含量更高，相对湿润环境（40%田间持水量）土壤线虫群落多度更高，但过多的土壤水分（80%田间持水量）不利于土壤生物群落结构的稳定。 土壤微生物和线虫群落的变化可以反映人工林栽植后沙地生态系统渐进性恢复过程。生物土壤结皮有利于其下土壤微食物网趋向于形成更为成熟的网络状结构，因此小叶锦鸡儿人工林栽植后形成的生物土壤结皮有利于沙漠化地区土壤生态系统的恢复。 |
| 英文摘要 | Biological soil crust as one of the key composition components plays an important role in ecosystem stability manintance and desertification rehabilitation in sandy ecosystems. However, few studies now focused on how biological soil crust affects soil food webs belowground after vegetation establishment. In this thesis, how the response of soil micro-food web to biological soil crust was investigated in Horqin Sandy Land, China. The changes of soil micro-food web with different ages of artificial forest were studied, the differences of soil micro-food web with and without biological soil crust were compared, and temperate and water availability effects on the soil micro-food web under biological soil crust were tested. The results were showed as followes:1. With the increase of sandy-fixation years, the biological soil crust developed from alga-lichen crust to moss crust, and crust organic carbon, total nitrogen and pH increased correspondingly. Significant changes in above-mentioned soil physicochemical properties, microbial communities and nematode communities appeared after 29-year sand-fixation. Total organic carbon and total nitrogen were the main soil properties for soil microbial communities, and total organic carbon, total nitrogen and pH for soil nematode communities. Soil microbial and nematode communities in different sand-fixation years were clearly separeated by redundancy analysis, and the preference of different microbes and nematode genera to habitat was discriminative due to their different responses to planting ages. It can be concluded that soil microbial and nematode communities as bioindicators reflected the progressive restoration process of sandy ecosystems.2. Comparsion experiment of soil micro-food web change with and without biological soil crust showed that organic carbon, total nitrogen and electronic conductivity in soils under biological soil crust were higher than that without biological soil crust. Soil properties under biological soil crust did not change significantly, while the presence of biological soil crust increased the phospholipid fatty acid and biomass carbon of microbes in the top 0–5 cm soil layer. Abundance, biomass carbon, and metabolic footprint of nematodes increased under biological soil crust in the top 0–5 cm soil layer. Biological soil crust enhanced carbon flow and connectance in the fungal and omnivore-predator channels. Therefore, biological soil crusts benefit to build a more complex, reticulated structure of the soil food web and contribute to the resilience of sandy ecosystems.3. An incubation experiment was conducted to examine the influences of temperature and water availability on soil biota under biological soil crust. Soil microbial and nematode communities did not show obvious response to temperature under biological soil curst. After 60 days incubation, 20% maximum field moisture capacity was most sutible for soil microbial communities. While after 30 days incubation, 40% maximum field moisture capacity was best for soil nematode communities. The existance of biological soil crust could provide suitable habitat and food resources for soil microbial and nematode communities, and help soil microbial and nematode communites resist to environment disturbance from temperature and water variations. Soil microbial and nematode communities reflected the progressive restoration process of the sandy ecosystems after binding sand with vegetation. Therefore, biological soil crusts were characterized by a relatively mature soil micro-food web. Therefore, the colonization of biological soil crust could contribute to the resilience of sandy ecosystems. |
| 中文关键词 | 沙地人工林 ; 生物土壤结皮 ; 土壤线虫 ; 磷脂脂肪酸 ; 土壤微食物网 |
| 英文关键词 | Sand-binding vegetation Biological soil crusts Soil nematodes PLFA Soil micro-food web |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 土壤学 |
| 来源机构 | 中国科学院沈阳应用生态研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/288043 |
| 推荐引用方式 GB/T 7714 | 管平婷. 沙地人工林下生物土壤结皮对土壤微食物网的影响[D]. 中国科学院大学,2018. |
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