干扰对黄土高原典型草原地上植被与繁殖更新的影响

发布时间：2019-05-11 19:45

【摘要】：干扰是草地退化、沙化、盐碱化的重要原因,也是草地生态系统生物多样性变化的主导因子。研究不同干扰措施对黄土高原典型草原地上植被与繁殖更新的影响,为退化黄土高原植被恢复和生物多样性维持提供一定的理论依据。本文以黄土高原典型草原云雾山自然保护区为研究区域,采用资料收集、野外调查和室内分析相结合的方法,分析比较了不同干扰措施对地上植被盖度、密度、物种丰富度、多样性、繁殖后代的丰富度,两种繁殖方式的密度和五种无性繁殖类型密度的影响,试验结果如下:1封育和放牧显著影响地上植被盖度、密度、生物量、枯落物厚度和枯落物生物量。与放牧相比,长期封育显著降低了地上植被的密度,而提高了植被盖度、生物量、枯落物厚度和枯落物生物量。封育和放牧措施显著影响物种丰富度、Margalef指数和Shannon-Wiener多样性指数,而对Simpson指数和Pielou指数无显著影响。与放牧相比,长期封育显著降低了地上植被的物种丰富度、Margalef指数和Shannon-Wiener多样性指数。DCA分析结果表明封育和放牧明显改变了植物群落结构和物种组成。2火烧显著降低了群落盖度、枯落物厚度、枯落物生物量,但显著提高了群落的密度。火烧对物种丰富度影响不显著,却显著降低了4个物种多样性指数Margalef指数、Shannon-Wiener指数、Simpson指数和Pielou指数。DCA分析结果表明火烧干扰明显改变了植物群落结构和物种组成。3黄土高原典型草原以多年生牧草占优势,植被更新主要以无性繁殖为主,以有性繁殖为辅。其中,多年生牧草主要依靠分蘖、根茎和分枝等方式来进行无性繁殖。封育和放牧显著影响草地繁殖更新的物种丰富度。与放牧地相比,封育23年草地更新苗的物种丰富度显著下降。管理措施对草地的繁殖更新密度和无性繁殖密度均有显著影响,而对有性繁殖密度无显著影响。封育23年草地的无性繁殖密度显著低于放牧地。放牧措施显著降低根茎型、分蘖型和分枝型密度,而对根蘖型和匍匐型密度影响不显著。封育和放牧措施对多年生草地的无性繁殖影响较大。封育和放牧措施对地上植被物种多样性和密度的影响可通过植物繁殖更新进行调节。4火烧显著提高了草地的繁殖更新密度和无性繁殖密度,而对有性繁殖密度和草地繁殖更新的物种丰富度影响不显著。火烧显著提高根茎型和分蘖型密度,而对根蘖型、分枝型和匍匐型密度影响不显著。在黄土高原典型草原,是以多年生克隆植物为主的草原生态系统,地上植被的繁殖更新更依赖于无性繁殖。植物繁殖更新贡献高低与火烧无关,而与草地群落物种组成相关。
[Abstract]:Disturbance is not only an important cause of grassland degradation, desertification and salinization, but also the dominant factor of grassland ecosystem biodiversity change. The effects of different disturbance measures on vegetation and reproduction and regeneration in typical grassland of Loess Plateau were studied, which provided a theoretical basis for vegetation restoration and biodiversity maintenance in degraded Loess Plateau. Taking Yunwu Mountain Nature Reserve of typical grassland in the Loess Plateau as the research area, this paper analyzed and compared the coverage, density and species richness of above-ground vegetation with different disturbance measures, using the methods of data collection, field investigation and indoor analysis, and analyzed and compared the above-ground vegetation coverage, density and species richness of different disturbance measures. Diversity, richness of reproductive progeny, density of two reproductive modes and density of five asexual reproduction types were studied. The results were as follows: (1) closure and grazing significantly affected vegetation cover, density and biomass of the above-ground vegetation, and the density and biomass of the above-ground vegetation were significantly affected by herding and grazing. Litter thickness and litter biomass. Compared with grazing, long-term closure significantly decreased the density of above-ground vegetation, but increased vegetation coverage, biomass, litter thickness and litter biomass. Closure and grazing measures significantly affected species richness, Margalef index and Shannon-Wiener diversity index, but had no significant effect on Simpson index and Pielou index. Compared with grazing, long-term closure significantly reduced the species richness of vegetation on the ground. Margalef index and Shannon-Wiener diversity index showed that fencing and grazing significantly changed plant community structure and species composition. (2) Fire significantly reduced community coverage, litter thickness and litter biomass. However, the density of the community was significantly increased. Fire had no significant effect on species richness, but significantly decreased the Margalef index and Shannon-Wiener index of four species diversity indexes. Simpson index and Pielou index. DCA analysis showed that fire disturbance significantly changed the structure and species composition of plant community. 3 the typical grassland of the Loess Plateau was dominated by perennial herbage, vegetation regeneration was mainly asexual reproduction, supplemented by sexual reproduction. Among them, perennials mainly rely on tillers, roots and branches to carry out asexual reproduction. Closure and grazing significantly affected the species richness of grassland reproduction and regeneration. Compared with grazing land, the species richness of new grassland seedlings decreased significantly after 23 years of closure. The management measures had significant effects on the reproduction and regeneration density and asexual reproduction density of grassland, but had no significant effect on the sexual reproduction density. The density of asexual reproduction in closed grassland for 23 years was significantly lower than that in grazing land. Grazing measures significantly decreased the density of rhizome type, tiller type and branch type, but had no significant effect on the density of root tiller type and creeping type. Sealing and grazing measures have great influence on asexual reproduction of perennial grassland. The effects of closure and grazing measures on species diversity and density of above-ground vegetation can be regulated by plant reproduction and regeneration. (4) Fire significantly increased the reproduction and regeneration density and asexual reproduction density of grassland. However, there was no significant effect on sexual reproduction density and species richness of grassland reproduction and regeneration. Fire significantly increased the density of rhizome type and tiller type, but had no significant effect on the density of root tiller type, branch type and creeping type. In the typical grassland of the Loess Plateau, it is a grassland ecosystem dominated by perennially cloned plants, and the reproduction and renewal of vegetation on the ground depends on asexual reproduction. The contribution of plant reproduction and regeneration was not related to fire, but to the species composition of grassland community.
【学位授予单位】：河南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S812

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