IMHE OpenIR  > 山地表生过程与生态调控重点实验室
苔藓植物对亚高山生态系统土壤呼吸的影响
Alternative TitleEffects of Bryophytes on Soil Respiration in Subalpine Ecosystems
刘涛
Subtype硕士
Thesis Advisor孙守琴
2017
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline自然地理
Keyword苔藓植物 亚高山生态系统 土壤呼吸 土壤有机碳
Abstract森林土壤有机碳库是陆地土壤有机碳库最大的组成部分,土壤有机碳库微小的变化都将导致大气二氧化碳浓大的改变。因此,土壤CO2排放成为陆地生态系统中的重要环节,是全球碳循环研究中关注的重点。苔藓植物作为森林生态系统重要的地被植物之一,虽然其在生态系统碳循环中的作用逐渐引起关注,但目前相关研究仍不足,特别是对苔藓植物对高山-亚高山生态系统土壤呼吸和土壤有机碳过程的影响还知之甚少。本研究从生态系统碳循环的最关键环节——土壤有机碳及其转化出发,以亚高山针叶林和亚高山灌丛对研究对象,通过地表苔藓植物去除试验,分析了保留和去除苔藓植物作用下土壤土壤呼吸和有机碳累积的变化,揭示苔藓植物对土壤碳转化过程的影响;并在此基础上,以亚高山针叶林为重点,分析了不同苔藓物种对土壤呼吸和有机碳累积的作用差异;结合土壤呼吸动态与土壤温湿度、土壤有机碳、微生物生物量和群落结构等的关系,分析苔藓植物对亚高山生态系统土壤碳转化和释放的潜在作用机制。主要结果如下:(1) 亚高山针叶林和亚高山灌丛苔藓植物体呼吸占分别占相应植被类型地表CO2排放量的比例很小,分别约为8.5%和5.8%;然而,从苔藓植物片层的角度,亚高山针叶林不同林龄赤茎藓和星塔藓苔藓片层对地表CO2排放量的比例分别能达到20.7%-35.1%和24.1%-37.5%。苔藓植物对亚高山生态系统地表CO2排放具有重要贡献。(2) 5-10月亚高山针叶林和亚高山灌丛地表总呼吸速率为2.14-4.32 μmol C m-2 s-1和 0.83-1.67 μmol C m-2 s-1。去除地面苔藓植物后,两个植被带地表CO2排放的季节动态无明显变化,但亚高山针叶林地表CO2排放速率约下降了44.4% ,亚高山灌丛地表CO2排放速率约下降了34.2%。地表苔藓植物对亚高山针叶林和亚高山灌丛地表CO2排放速率有显著影响。(3) 5-10月亚高山针叶林和亚高山灌丛土壤净呼吸速率为1.97-3.99 μmol C m-2 s-1和0.76-1.59 μmol C m-2 s-1。地表苔藓植物的去除并不改变土壤呼吸的季节变化趋势;然而,去除地面苔藓植物后,两个植被带土壤净呼吸速率分别下降了39.3%和30.3%。地表苔藓植物对亚高山针叶林和亚高山灌丛土壤CO2排放速率有显著影响。由此认为,目前以裸地土壤呼吸测定值作为参考值对森林土壤碳排放进行研究可能会对土壤碳排放造成低估,因此为了提高生态系统碳预算模型的估算精度,应将苔藓地被植物的影响作为未来碳预算模型的重要因子之一进行考虑。(4) 地表覆被类型对亚高山针叶林不同林龄地表CO2排放速率均具有显著影响。亚高山针叶林各林龄苔藓覆被下的地表和土壤CO2排放速率均明显高于裸地;虽然次生林和中林龄中两种不同苔藓植物作用下的地表CO2排放速率表现出了明显的差异,但无论是次生林、中龄林、成熟林还是过熟林,两种苔藓植物作用下土壤净CO2排放速率均无差异。(5) 不同苔藓植物及裸地条件下亚高山针叶林土壤温湿度无显著差异;去除地面苔藓植物对5-10月亚高山针叶林土壤平均温湿度的大小或季节变化趋势无显著影响,但导致生长季内土壤温湿度的日变化范围增大。然而,地面苔藓植物的去除显著增加了亚高山灌丛土壤平均温湿度和土壤温度的日变化幅度。(6) 去除和保留苔藓条件下,亚高山针叶林和亚高山灌丛土壤呼吸速率和土壤温度均有显著的指数相关关系。去除和保留苔藓植物条件下土壤温度分别能够解释亚高山针叶林地表和土壤呼吸的36.2%和44.8%、亚高山灌丛地表和土壤呼吸的31.8%和43.0%。虽然如此,去除地面苔藓植物后亚高山针叶林和高山灌丛土壤温度的变化趋势与相应植被类型土壤CO2排放速率的变化趋势不一致甚至相反,说明土壤温度的变化不能解释苔藓植物对土壤CO2排放速率的作用。(7) 地表苔藓植物对亚高山针叶林和亚高山灌丛表层土壤总有机碳和溶解性有机碳含量有显著影响,而且这种影响主要集中在0-5cm土壤表层;特别是赤茎藓与星塔藓和裸地相比其表层土壤具有较高的总有机碳和溶解性有机碳含量。去除地面苔藓植物后,亚高山针叶林和亚高山灌丛0-5cm土壤总有机碳含量分别下降了65.2%和35.1%。去除地面苔藓后土壤总有机碳和溶解性有机碳与土壤呼吸的一致变化趋势暗示了土壤有机碳的变化可能是解释苔藓作用下土壤呼吸速率较高的潜在原因。(8) 地表苔藓植物的去除显著降低了亚高山针叶林和亚高山灌丛0-5cm表层土壤微生物碳含量;尤其是赤茎藓相对于星塔藓和裸地其土壤具有较高的微生物碳含量。与对照相比,去除苔藓植物后亚高山针叶林和亚高山灌丛0-5 cm土壤微生物碳含量分别下降了42.6%和47.9%。去除地面苔藓植物后,亚高山针叶林0-5cm土壤磷脂脂肪酸(PLFA)总含量以及细菌和真菌标志物含量均显著降低;亚高山灌丛土壤磷脂脂肪酸总含量无显著变化,但土壤总细菌和一般性细菌(P = 0.008)标志物含量明显降低。去除苔藓植物后亚高山针叶林和亚高山灌丛微生物碳和群落结构的这一变化暗示了土壤基质质量的下降,进一步说明苔藓植物作用下较高的土壤呼吸速率可能是由于细菌对土壤有机碳和养分的消耗导致的。
Other AbstractOrganic carbon stock of forest soil is the biggest part of terrestrial carbon reservior, small changes of soil organic carbon stock will lead to big changes of the atmospheric CO2 concentration. Soil CO2 emissions, therefore, become the important link in the terrestrial ecosystem, it is the focus in the global carbon cycle research. Bryophytes is an important one of the groundcover plants of forest ecosystem, it effects on soil physical and chemical properties, but, these effects have not been associated with soil organic carbon conversion process in the current study.This research starting from the most key link of ecosystem carbon cycle, in subalpine coniferous forest and subalpine thickets on the object of study, through the surface bryophyte remove test, retention and removal of bryophytes are analyzed under the action of the change of soil respiration and soil organic carbon accumulation, reveal the bryophytes effects on soil carbon conversion process. With an emphasis on subalpine coniferous forest, we analyzed the different moss species on soil respiration and the role of organic carbon accumulation difference. We combined with dynamic soil respiration and soil temperature and humidity, soil organic carbon, microbial biomass and community structure, etc , analyzed the potential mechanism that ryophytes in subalpine ecosystems and release soil carbon. The main conclusions in this paper are as follows:(1) The proportion of CO2 emissions that bryophytes in subalpine coniferous forest and subalpine shrub is very small, about 8.5% and 8.5% respectively. The proportion of CO2 emissions that Pleurozium schreberi Hylocomiastrum in different age subalpine coniferous forest reached 20.7% 35.1% and 24.1% 37.5% respectively. Bryophytes in subalpine ecosystems surface has the important contribution of CO2 emissions.(2) Subalpine coniferous forest and subalpine scrub the surface total respiratory rate were 2.14-4.32 μmol C m-2 s-1 and 0.83-1.67 μmol C m-2 s-1between May and October. After Remove the ground bryophytes, the surface seasonal dynamics of CO2 emissions were no significant change. CO2 releasing rate decreased respectively 44.4% and 34.2% in subalpine coniferous forest and subalpine scrub. The surface of the bryophytes had significant impact on CO2 emissions rate in subalpine coniferous forest and subalpine scrub.(3)The soil respiration rate were 1.97-3.99 μmol C m-2 s-1 and 0.76-1.59 μmol C m-2 s-1 in subalpine coniferous forest and subalpine scrub between May and October. The surface of the bryophytes removal does not change trends of seasonal change of soil respiration. However, after removing the ground after bryophytes, net soil respiration rate decreased by 39.3% and 30.3% respectively. The surface of the bryophytes have remarkable influences on soil CO2 emission rate. It is believed that bare soil respiration with reference to the measured value of study on forest soil carbon emissions could be underestimated on soil carbon, so in order to improve the estimation precision of ecosystem carbon budget model, the influence of the moss cover plant should be as one of the most important factor in the future carbon budget model considering.(4) Soil CO2 emissions rate of under moss were significantly higher than that of bare land. The surface CO2 emissions rate of two kinds of moss showed obvious difference in the secondary forest and plantation age forest. But soil net CO2 emissions rate had no difference between secondary, mid-maturation forest, mature forest and overripe forest. (5) Soil temperature and humidity of different bryophytes and bare land were no significant difference in subalpine coniferous forest; Removed the ground bryophytes had no obvious effect on subalpine coniferous forest soil temperature and humidity, but lead to the growing season in the diurnal variation of soil temperature and humidity range. However, it was increased significantly to daily variation amplitude of average temperature and humidity and soil temperature in subalpine scrub.(6) There was a significant exponential correlation between soil respiration rate and soil temperature in subalpine coniferous forest and sub alpine shrub. The soil temperature under the condition of removal and reservation of bryophytes could explain 36.2% and 44.8% of the surface and soil respiration of the subalpine coniferous forest, and the surface and soil respiration of the subalpine shrub was about 31.8% and 43%, respectively. Nevertheless, the removal of ground bryophytes after trend of subalpine coniferous forest and alpine shrub soil temperature and soil CO2 emission rate of the corresponding vegetation types are inconsistent or even on the contrary, that the change of soil temperature can explain the bryophytes rate on soil CO2 emissions.(7) The surface of the bryophytes of subalpine coniferous forest and subalpine thickets of soil total organic carbon and dissolved organic carbon content has significant effect, and the impact is mainly concentrated in the 0 to 5 cm soil surface; Especially red moss compared with star tower moss and bare stem its surface soil with high total organic carbon and dissolved organic carbon content. Remove the ground bryophytes, subalpine coniferous forest and subalpine thickets 0 to 5 cm soil total organic carbon content decreased by 65.2% and 35.1% respectively. After removal of moss on the ground soil total organic carbon and dissolved organic carbon and soil respiration consistent trends suggest that the changes in soil organic carbon can be explain moss under the action of the underlying cause of soil respiration rate is higher.(8) The removal of ground bryophytes significantly decreased in subalpine coniferous forest and sub alpine shrub 0-5cm surface soil microbial carbon content; especially microbial carbon content of red moss stems relative to the Star Tower and the moss bare soil has a high. Compared with the control, the soil microbial biomass carbon content was decreased by 42.6% and, respectively, after the removal of bryophytes in subalpine coniferous forest and sub alpine shrub 0-5 cm. The removal of ground bryophytes, subalpine coniferous forest soil 0-5cm fatty phosphatidic acid (PLFA) content and total bacterial and fungal markers were significantly lower; the total acid content of subalpine shrub soil phospholipid fatty no significant change, but the total soil bacteria and common bacteria (P = 0.008) markers were significantly reduced. This change after removal of bryophytes in subalpine coniferous forest and sub alpine shrub community structure and microbial carbon implies the decline of soil mass, explains the bryophytes under higher soil respiration rates may be due to bacteria on soil organic carbon and nutrient consumption.
Pages57
Language中文
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/24575
Collection山地表生过程与生态调控重点实验室
Affiliation中国科学院成都山地灾害与环境研究所
First Author Affilication中国科学院水利部成都山地灾害与环境研究所
Recommended Citation
GB/T 7714
刘涛. 苔藓植物对亚高山生态系统土壤呼吸的影响[D]. 北京. 中国科学院大学,2017.
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