库布齐沙漠东段不同沙丘类型土壤种子库特征研究

发布时间：2018-02-22 19:52

本文关键词： 库布齐沙漠东段土壤种子库相似性演替　出处：《中国农业科学院》2015年硕士论文　论文类型：学位论文

【摘要】：本文采用空间替代时间的方法,结合野外地上植被调查和土壤种子库萌发实验,选择处于不同沙丘类型作为研究对象,即固定沙丘,半固定沙丘,半流动沙丘,流动沙丘,研究了不同沙丘类型土壤种子库的特征,阐述了土壤种子库的物种组成和数量特征、空间分布格局,分析土壤种子库与地上植被的关系,探讨沙丘固定过程中种子库的变化规律,以及土壤种子库在沙丘植被恢复、治理中的作用,为库布齐沙漠固沙植被建设和生态管理提供科学依据。(1)不同沙丘类型地上植被调查,共发现有11科27种植物,一年生植物分别占固定沙丘、半固定沙丘、半流动沙丘和流动沙丘地上植被物种数的58.82%、66.67%、57.90%、60.00%。随着沙丘的固定,地上植被Margalef丰富度指数、Simpson多样性指数、Shannon-Wiener指数、Pielou均匀度指数均逐渐增大,说明地上植被物种多样性逐渐增大、物种分布逐渐均匀。(2)不同沙丘类型土壤种子库共发现10科25种植物,一年生草本植物分别占固定沙丘、半固定沙丘、半流动沙丘和流动沙丘土壤种子库全部物种数的78.57%、69.23%、52.94%、61.54%。随着沙丘的固定,土壤种子库的密度逐渐增加。一年生草本植物占固定沙丘、半固定沙丘、半流动沙丘和流动沙丘土壤种子库密度的96.55%、98.30%、95.26%、97.15%。土壤种子库Margalef丰富度指数、Simpson多样性指数、Shannon-Wiener指数、Pielou均匀度指数随着沙丘的固定逐渐增大,说明土壤种子库物种多样性增加,物种分布逐渐均匀。(3)随着土壤剖面的加深,土壤种子库的物种数和密度逐渐减少。土壤种子库主要集中于0-5cm,分别占固定沙丘、半固定沙丘、半流动沙丘和流动沙丘全部种子库的76.30%、90.21%、68.67%、80.10%。不同沙丘类型不同坡位土壤种子库密度为:在固定沙丘和半固定沙丘,不同微地形土壤种子库密度均为迎风坡背风坡坡顶,沙丘底部沙丘中部沙丘顶部;在流动沙丘和半流动沙丘,不同微地形土壤种子库密度为背风坡迎风坡坡顶,在半流动沙丘沙丘中部沙丘底部沙丘顶部,在流动沙丘,沙丘底部沙丘中部沙丘顶部。(4)不同沙丘类型土壤种子库与土壤理化性质相关性的分析表明:土壤含水量、土壤容重与土壤种子库密度显著相关(P0.05),有机质含量、全氮、速效氮、土壤机械组成与土壤种子库的大小无显著相关性(P0.05)(5)不同沙丘类型相邻演替阶段地上植被间、土壤种子库间均处于中等相似水平,物种替代率不高,而固定沙丘与半流动沙丘、流动沙丘处于中等不相似水平,说明从流动沙丘(演替前期)到固定沙丘(演替后期)物种替代率较高。而固定沙丘、半固定沙丘、半流动沙丘、流动沙丘土壤种子库与地上植被的相似性分别为0.6316、0.5556、0.6364、0.6471,整体处于中等相似水平。
[Abstract]:In this paper, with the method of spatial substitution time, combined with field vegetation investigation and soil seed bank germination experiment, we selected different types of sand dunes as research objects, that is, fixed dunes, semi-fixed dunes, semi-mobile dunes, mobile dunes. The characteristics of soil seed banks of different dune types were studied. The species composition and quantitative characteristics, spatial distribution pattern of soil seed banks, and the relationship between soil seed banks and aboveground vegetation were analyzed. The changes of seed bank in the process of sand dune fixation and the role of soil seed bank in the restoration and management of sand dune vegetation were discussed, which provided scientific basis for the construction and ecological management of sand fixation vegetation in Kubuqi Desert. A total of 27 species belonging to 11 families were found. Annual plants accounted for 58.82and 66.67% of the species of aboveground vegetation in fixed dunes, semi-fixed dunes, semi-fixed dunes, semi-mobile dunes and mobile dunes, respectively. With the fixation of sand dunes, The Margalef richness index and Margalef diversity index of aboveground vegetation and the evenness index of Pielou increased gradually, indicating that the species diversity of aboveground vegetation gradually increased, and the species distribution gradually homogenized. 2) 10 families and 25 species of plants were found in soil seed bank of different dune types. Annual herbaceous plants occupy fixed sand dunes, semi-fixed sand dunes, semi-flowing sand dunes and mobile dune soil seed banks, respectively. The density of soil seed banks increases gradually with the fixation of sand dunes, and the annual herbaceous plants account for the fixed sand dunes. The density of soil seed bank in semi-fixed sand dunes, semi-mobile dunes and mobile dunes was 96.555.98.30 and 95.266.15.The Margalef richness index of soil seed bank and the Margalef diversity index of soil seed bank increased gradually with the fixation of sand dunes. The results showed that the species diversity of soil seed bank increased, and the species distribution gradually homogenized. 3) with the deepening of soil profile, the species number and density of soil seed bank decreased gradually. Soil seed bank mainly concentrated in 0-5 cm, accounting for fixed sand dunes and semi-fixed dunes, respectively. The density of soil seed bank in different types of sand dunes is 80.107.The density of soil seed banks in fixed dunes and semi-fixed dunes is that in fixed dunes and semi-fixed dunes, the density of soil seed banks in different microtopography is the top of leeward slope on upwind slope. At the bottom of the dune, at the top of the dune in the middle of the dune, at the top of the leeward slope at the top of the leeward slope, at the top of the dune at the bottom of the dune in the middle of the semi-mobile dune, and at the mobile dune at the mobile dune, The correlation between soil seed bank of different dune types and soil physical and chemical properties was analyzed. The results showed that soil moisture content, soil bulk density and soil seed bank density were significantly correlated with soil seed bank density, organic matter content, total nitrogen, available nitrogen. There was no significant correlation between soil mechanical composition and the size of soil seed bank (P 0.05). The soil seed bank was at a medium similar level and the rate of species substitution was not high, but fixed sand dunes and semi-mobile dunes were in the middle similarity level between the different types of sand dunes in the adjacent succession stage, and there was no significant correlation between the soil mechanical composition and the size of soil seed banks. The medium dissimilarity level of mobile dune indicates that the species substitution rate is higher from mobile dune (early succession) to fixed dune (late succession), while fixed dune, semi-fixed dune, semi-mobile dune, The similarity between soil seed bank of mobile sand dunes and aboveground vegetation was 0.63160.55560.63640.471. the whole soil was at a moderate similarity level.
【学位授予单位】：中国农业科学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S154

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