猪毛蒿沿沙—土斑块界面分布格局及其影响机制

发布时间：2018-05-17 12:01

本文选题：猪毛蒿 + 沙-土界面　；参考：《宁夏大学》2017年硕士论文

【摘要】：在人为活动和自然干扰下,荒漠草原大块连续分布的自然景观,被其他非适宜生境分隔成许多面积较小的生境斑块,导致斑块破碎分离并由简单趋向复杂。猪毛蒿在这些破碎斑块中占重要地位,而且沿着沙性土与壤质土的过渡界面呈现有规律的分布,研究这种规律的形成机理能够为草原改良和生态恢复提供理论基础。本文采用野外样带调查、室内物理和化学分析以及冗余分析和地统计学等方法,研究了毛乌素沙地西南缘一个典型沙性土斑块与壤质土斑块过渡带(简称沙-土斑块界面)的猪毛蒿分布格局及其与土壤、植被的相互关系。主要结论如下:1.沙-土斑块界面植物主要为禾本科、豆科、菊科,是其广适性的表现。本研究的野外调查物种调查结果中共有植物28种,分属12科27属,多年生草本占优势,多为禾本科、豆科、菊科物种。界面植被呈现为针茅群落与猪毛蒿群落的交错分布,短花针茅、猪毛蒿在各自群落中占优势地位,物种丰富度最高出现在界面上。土壤沙化程度的增加,针茅、胡枝子的重要值逐渐减小,猪毛蒿由于其卓越的抗逆性,其重要值逐渐增加最终发展为群落建群种,其中有20个样方猪毛蒿重要值超过1/3,甚至有些超过一半以上。生物量也有类似的变化趋势。2.猪毛蒿群落特征与土壤因子都存在界面变化,有空间自相关界面猪毛蒿群落样带平均高度、盖度、生物量、密度、丰富度、香农威纳指数、均匀度指数、优势度指数随样带延伸而变化。荒漠草原存在大量丛生植物如短花针茅、糙隐子草等,导致群落密度与生物量相关性不高。土壤水分、养分和粒径也随样带表现出梯度变化,体现了界面效应,且有较强的空间自相关。猪毛蒿与与土壤各层粒径都表现出极度相关。3.影响猪毛蒿群落物种多样性和功能群多样性的主要因子是底层土壤质地与养分。对针茅-猪毛蒿过渡群落分布及其物种多样性变化有显著影响的主要土壤环境因子分别为20-40cm 土层黏粉粒和20-40cm 土层有机碳。对植被功能群有显著影响的主要土壤环境因子分别为20-40cm粗砂粒和10-20cm全磷。表层土壤养分和质量的变化也有植物分布格局的形成有显著相关,但解释量不高。主要还是20-40cm 土壤粒径约束下物种扩散竞争的空间格局。植物群落随土壤粒径增大多样性逐渐降低,植物分布越呈密集的小片状分布,物种丰富度也降低。4.荒漠草原沙-土斑块界面土壤底层粗砂粒的分布格局决定猪毛蒿群落的空间分布。研究发现各土层有机碳与生物量均呈现极显著相关性,且相关性由表层到深层递减。表层土由于外界干扰较多,其相关性不明显。不同土层粒径含量与群落盖度、生物量的相关性对比发现由于荒漠草原土壤受侵蚀作用强,土壤表层粒径与盖度生物量的相关性不显著,越往底层反而越显著;土壤中局部粗砂粒含量高使土壤团粒结构丧失、土壤孔隙减小,渗透阻力增大,导致水分散失增大,限制物种进入,形成单优先锋物种群落。表现出地上植被群落与土壤下伏地层或成土母质的相关性更为明显。研究结果表明底层土壤质地是决定荒漠草原地区岛状板块猪毛蒿群落的构建的主要因子。
[Abstract]:Under human activities and natural disturbances, the continuous distribution of natural landscapes in large desert grassland is separated by other unsuitable habitats into many smaller habitats, resulting in fragmented patches and simple tendency to complex. Artemisia porcine is important in these fragmented patches, and along the transition interface between sandy soil and loam soil In this paper, a typical sandy soil patch in the southwest margin of the Maowusu Sandy Land and the transition zone of the loamy soil patch are studied by field sampling, indoor physical and chemical analysis, redundancy analysis and geostatistics. The distribution pattern of Artemisia Artemisia and its relationship with soil and vegetation. The main conclusions are as follows: 1. sand soil patch interface plants are mainly gramineaceae, Leguminosae, and Compositae. There are 28 species of plant species in this study, belonging to 12 families, 27 genera, and perennial herbs. The interface vegetation is the interlaced distribution of the Stipa community and the Artemisia annua community, and the species richness of the species is the highest in the community. The soil desertification degree increases, the important value of the Stipa, the Lespedeza is gradually reduced, and the Artemisia Artemisia is due to its excellent resistance. The important value of its important value gradually increased to the community construction, among which 20 samples were more than 1/3, even some more than half. There was a similar trend in the biomass of.2., and there was an interface change between the community characteristics and soil factors of the Artemisia Artemisia, and the average height and coverage of the spatial autocorrelation interface of the community sample zone of Artemisia Artemisia. The biomass, density, richness, Shannon Wiener index, evenness index and dominance index vary with the sample belt. There are a large number of cluster plants such as Stipa short and saphenous weed in desert steppe, which leads to the low correlation between the density and biomass of the community. Soil moisture, nutrients and grain sizes also show gradient changes with the sample zone, reflecting the interfacial effect. The main factors affecting the species diversity and functional group diversity of the Artemisia hairy Artemisia community are the underlying soil texture and nutrient. The main soil environment which has significant influence on the distribution of the Transitional Community and the variety of species diversity of the Artemisia hairy Artemisia Artemisia is the main factor affecting the diversity of the species and functional groups of the Artemisia annua community..3. The factors are 20-40cm soil layer clay particle and 20-40cm soil layer organic carbon respectively. The main soil environmental factors that have significant influence on the vegetation functional groups are 20-40cm coarse sand grains and 10-20cm total phosphorus, respectively. The change of soil nutrient and quality also has significant correlation with the formation of plant distribution pattern, but the amount of interpretation is not high. It is mainly the 20-40cm soil. The spatial pattern of species diffusion competition under the restriction of particle size. The diversity of plant communities gradually decreased with the increase of soil particle size, and the more dense small flaky distribution of plant distribution. The species richness also reduced the distribution pattern of the coarse sand grains at the bottom of the sandy soil patch interface of.4. desert grassland. There is a significant correlation between organic carbon and biomass, and the correlation is decreasing from the surface to the deep. The correlation of the surface soil is not obvious because of the more external interference. The correlation of the grain size and the community coverage and the biomass of the different soil layers shows that the soil surface grain size and the cover biomass are strong due to the strong erosion of the desert grassland soil. The correlation is not significant, and the more significant it goes to the bottom. The high content of coarse sand grains in the soil causes the loss of soil aggregate structure, the decrease of soil porosity and the increase of osmotic resistance, which leads to the increase of water loss, limiting the entry of species and forming a single superior pioneer species community. The results show that the texture of the underlying soil is the main factor determining the construction of the Artemisia annua community in the desert grassland area.
【学位授予单位】：宁夏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q948

【参考文献】