洋河口湿地土壤碳、氮、磷生态化学计量特征对互花米草入侵的响应

发布时间：2018-06-20 07:50

本文选题：洋河口湿地 + 互花米草入侵　；参考：《青岛大学》2017年硕士论文

【摘要】：本文以洋河口湿地为研究对象,对洋河口湿地入侵物种互花米草的分布现状以及扩展速度进行了研究,在此基础上分析了互花米草入侵时间序列下土壤碳、氮、磷、C/N、C/P、N/P等的分布特征和相关性,探讨了互花米草的入侵对湿地土壤碳、氮、磷化学计量的影响机制。研究结论如下:(1)2009年-2016年间,洋河口湿地互花米草斑块面积从1.7hm2增长到78.4hm2,表明了互花米草繁殖能力和扩散能力很强。不同地区互花米草的面积年扩展倍数不同,与本研究中其他区域相比洋河口湿地互花米草面积年扩展倍数最大,这主要与洋河口区域的互花米草种子库以及该区域生态因子适宜互花米草的生长发育和扩散有关。(2)洋河口互花米草不同入侵时间序列下,各样地土壤TOC含量表现为SAF-8SAF-5SAF-1MF,即互花米草斑块中土壤有机碳含量随着入侵时间延长而增加。垂直方向上,由于互花米草生长年限较短(3a),且互花米草为C4植物,可以促进土壤表层TOC的累积,导致样地SAF-8、SAF-5表层(0~10cm)土壤TOC含量均高于中、下层(20~60cm)土壤TOC含量。(3)不同入侵时间序列下土壤TN含量表现为SAF-8SAF-5SAF-1MF,分析原因主要是:互花米草根际分布有丛枝菌根真菌等多种共生固氮微生物,导致互花米草斑块中土壤TN含量随着入侵时间延长而增加,即在时间尺度上表现出积累效应。同时,洋河口湿地TN含量受潮汐作用、盐水入侵、咸淡水交汇等水动力学作用影响显著,受外源干扰较大,是各个样地土壤TN含量垂直分布规律不明显的主要原因。(4)样地SAF-1、SAF-5、SAF-8同属于互花米草湿地,其土壤中TP含量表现为SAF-1SAF-5SAF-8,即互花米草斑块中土壤TP含量随着入侵时间延长而增加,与土壤中TN含量与互花米草入侵的相关变化特征一致。垂直方向上,总体表现出TP表层富集的特征。这主要与河口潮滩湿地表层土壤以黏粒为主,对TP具有较强的吸附能力,同时TP受垂直方向的淋溶作用影响很小有关。(5)互花米草入侵时间序列上,湿地土壤C/N表现为随着互花米草的入侵时间的增加而升高,而C/P、N/P变化规律相反,表现为随着互花米草的入侵时间的增加呈现递减的规律。互花米草枯落物分解导致土壤中C含量较高,且C分解速率较低是土壤C/N随着互花米草入侵时间的增长而增加的重要原因。随着入侵时间的增长,C/P呈现递减的变化趋势,这与互花米草湿地随着入侵时间的增长,TP的升高速率要高于TOC的增长速率有关。而N/P呈现递减的变化趋势与N素作为植物叶绿素的主要成分,互花米草生长需要消耗大量的N元素,而P元素相对消耗量较小有关。
[Abstract]:In this paper, the distribution and expansion rate of Spartina alterniflora, an invasive species in Yanghekou wetland, was studied, and the soil carbon and nitrogen under the invasion time series of Spartina alterniflora were analyzed. The distribution and correlation of C / P / P / P et al. The influence mechanism of Spartina alterniflora invasion on soil carbon, nitrogen and phosphorus stoichiometry was discussed. From 2009 to 2016, the patch area of Spartina alterniflora in Yanghekou wetland increased from 1.7hm2 to 78.4 hm-2, which indicated that Spartina alterniflora had strong reproductive and diffusive ability. The annual expansion times of Spartina alterniflora in different areas are different, and the annual expansion multiple of Spartina alterniflora in Yanghekou Wetland is the largest compared with other regions in this study. This is mainly related to the seed bank of Spartina alterniflora in the estuary of Yanghe River and the ecological factors suitable for the growth, development and diffusion of Spartina alterniflora in this region. (2) under different invasion time series of Spartina alterniflora in Yanghe River Estuary, The TOC content of soils in various plots was SAF-8SAF-5SAF-1MF.The content of soil organic carbon in Spartina alterniflora patches increased with the time of invasion. In vertical direction, because Spartina alterniflora has a shorter growth time, and Spartina alterniflora is a C4 plant, it can promote the accumulation of TOC in the surface layer of soil, resulting in the TOC content of the soil of SAF-8 and SAF-5 is higher than that of medium soil. Under different invasion time series, the TN content of soil was SAF-8SAF-5SAF-1MFF. The main reason was that arbuscular mycorrhizal fungi and other symbiotic nitrogen-fixing microbes were distributed in rhizosphere of Spartina alterniflora, and the main reason was that arbuscular mycorrhizal fungi and other symbiotic nitrogen-fixing microorganisms were distributed in the rhizosphere of Spartina alterniflora. As a result, soil TN content in Spartina alterniflora patches increased with the time of invasion, that is, accumulated effect on time scale. At the same time, the TN content of Yanghe River estuary wetland is affected by tidal action, salt water intrusion, salt and fresh water intersection, etc. It is the main reason that the vertical distribution of TN content in soil is not obvious. (4) SAF-1, SAF-5 and SAF-8 belong to Spartina alterniflora wetland, and the TP content in soil is SAF-1SAF-5SAF-8, that is, TP content in Spartina alterniflora patch increases with the time of invasion. The change of TN content in soil was consistent with that of Spartina alterniflora invasion. In the vertical direction, the TP surface layer is generally enriched. This is mainly related to the fact that the surface soil of estuarine tidal flat wetland is mainly clay and has a strong adsorption capacity for TP, and that TP is slightly affected by vertical leaching in the time series of invasion of Spartina alterniflora. The C / N of wetland soil increased with the invasion time of Spartina alterniflora, but the change rule of C / P N / P was opposite, which was the law of decreasing with the invasion time of Spartina alterniflora. The decomposition of litter of Spartina alterniflora led to the higher content of C in soil and the lower decomposition rate of C was the important reason for the increase of soil C / N with the increase of invasion time of Spartina alterniflora. With the increase of invasion time, C / P decreased, which was related to the increase rate of TP in Spartina alterniflora wetland with the increase of invasion time, which was higher than that of TOC. However, the decreasing trend of N / P was related to N element as the main component of chlorophyll in plants. The growth of Spartina alterniflora needed to consume a large amount of N elements, but the relative consumption of P element was relatively small.
【学位授予单位】：青岛大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q948.1

【参考文献】