【作者】 刘红梅；

【导师】 卫智军；

【作者基本信息】 内蒙古农业大学 ， 草业科学， 2011， 博士

【摘要】 以短花针茅草原生态系统为研究对象,在2006~2010年期间,对轮牧区不同利用时间及不同放牧制度小区的植物种群数量特征进行动态监测,并分种记录植物种群的高度、盖度、密度,计算其重要值。每年牧草生长旺季对轮牧区不同利用时间及不同放牧制度小区的植物分种齐地面剪割,阴干称重。2009年和2010年在不同试验处理小区选取代表性样地,按机械取样法对样方内植物种类、高度、盖度、密度等群落数量特征进行详细调查,分析不同试验处理小区各植物种群的种间关系和生态位,并对主要植物种群的空间异质性进行研究,同时在相应的样方取0~10cm土样带回实验室进行土壤养分常规测定,分析土壤养分空间分布特点。最终采用DCA(Detrended correspondence analysis,除趋势对应分析)和CCA(Canonical correspondence analysis,典范对应分析)方法探讨植物种群、土壤养分和各试验处理小区之间的关系。主要研究结果如下:1轮牧区不同利用时间下,早期放牧小区主要植物种群的高度均较低,短花针茅的盖度和密度较大;晚放牧小区无芒隐子草盖度和密度较小。不同放牧制度,短花针茅盖度和密度为自由放牧区>轮牧区>对照区;无芒隐子草盖度和密度为对照区与轮牧区接近,均大于自由放牧区;碱韭盖度和密度对照区>轮牧区>自由放牧区。2轮牧区不同利用时间下,群落地上现存量表现为,中期放牧区>晚期放牧区>早期放牧区。不同放牧制度下,群落地上现存量对照区>轮牧区>自由放牧区。3轮牧区不同利用时间下,晚放牧小区植物种群种间关系复杂,早放牧区植物种间关系简单。不同放牧制度下,放牧能够促使种间关系明显加强,而轮牧更能够使种间相关性表现明显。轮牧、自由放牧和对照区物种间种间亲和性的表现均是以正相关为主。4轮牧区不同利用时间下,早期放牧和晚期放牧短花针茅生态位宽度较大,碱韭和无芒隐子草在中期放牧小区生态位宽度较大。不同放牧制度,短花针茅生态位宽度表现为自由放牧区>轮牧区>对照区,碱韭和无芒隐子草生态位宽度均表现为轮牧区>自由放牧区>对照区。主要植物种群之间及其与阿氏旋花、寸草苔、细叶葱和猪毛菜的生态位重叠程度比较大。5轮牧区不同利用时间下,中期放牧区3个植物种群随机因素引起的空间变异较小,植物种群最大空间变异程度较大。不同放牧制度,主要植物种群空间异质性均比较小,受结构性因素影响较大。同一试验处理小区内3个主要植物种群主要以镶嵌的斑块状分布为主。6轮牧区不同利用时间下,早放牧区随机因素引起土壤全氮、速效钾和有机碳空间异质性较大。晚放牧区全氮和碱解氮最大空间变异程度较大。不同放牧制度下,全氮和有机碳由随机因素引起的空间变异表现为自由放牧区>轮牧区>对照区,碱解氮、全钾和速效钾由随机因素引起的空间变异表现为对照区>轮牧区>自由放牧区。土壤养分主要受结构性因素影响,受随机因素影响较小,空间异质性较小,空间自相关性较强。7在轮牧区不同利用时间下,早放牧和和晚放牧区主要植物种群与土壤养分空间分布关系密切。在不同放牧制度下,主要植物种群与土壤养分之间的关系密切程度轮牧区>对照区>自由放牧区。主要植物种群与土壤养分的关系碱韭>无芒隐子草>短花针茅。轮牧较自由放牧更有利于使植物种群空间分布保持稳定。8轮牧区不同利用时间下的中期放牧最为合理,不同放牧制度下划区轮牧对短花针茅草原可持续发展更为有利。更多还原

【Abstract】 A dynamic monitoring of population characteristics under different rotational grazing time and grazing system of Stipa breviflora desert steppe ecosystem were investigated during 2006-2010, which record the height, coverage and the density of plant populations in order to calculate the critical value, forage in rotational grazing area under different utilization grazing time and different grazing system were cut on the ground, dried and weighed. In 2009 to 2010, selected for different treatments and representative sample, laid dynamic monitoring plots of plant height, coverage, density and other characteristics of community indicators of the number of detailed investigation by mechanical sampling of plant species within plots, then analyzed of plant interspecific relationship and niche among different treatments of the species area, and the main spatial heterogeneity of plant populations were studied simultaneously. Meanwhile the corresponding plots for 0~10cm soil samples were taken back to the laboratory for routine determination of soil nutrients to analyze spatial distribution of soil nutrients under different treatments plot which sort by DCA and the CCA end method to study the relationship among plant species, soil nutrients and plot treatments. The main results were as follows:1 Different time in rotational grazing area, The height of main plant populations in late grazing area were lower in early grazing area, the coverage and density of Stipa breviflora were greater; the coverage and density of Cleistogenes songorica was lower in late grazing area. While in different grazing systems, the coverage and density of Stipa breviflora were continuous grazing area> rotational grazing area> control area; which of Cleistogenes songorica for the nearly equal between control area and rotational grazing area and both of which larger than that in continuous grazing area, coverage and density of Allium polyrhizum showed that in the control area> rotational grazing areas> continuous grazing area.2 Different time in rotational grazing area, the community aboveground biomass showed mid-grazing area> late grazing area> early grazing area. In different grazing system, the community aboveground biomass was control area> rotational grazing area> continuous grazing area.3 Interspecific relationships appeared intricately in late grazing area whereas simple in early grazing area at different use of rotational grazing time. In different grazing systems, grazing can significantly strengthen the interspecific relationships, and rotational grazing was better able to show significant correlation between species. Species compatibility among Rotational grazing, continuous grazing and control area showed a positive correlation.4 Early grazing and late grazing were benefit for niche breadth of Stipa breviflora at different use of rotational grazing time, while mid-grazing was good for that of Cleistogenes songorica. In different grazing systems, the niche breadth of Stipa breviflora showed continuous grazing area> rotational grazing area> control area, which of Allium polyrhizum and Cleistogenes songorica appeared as rotational grazing area> continuous grazing area> control area. Niche overlap among the main plant populations and Convolvulus ammannii, Carex duriuscula, Allium tenuissimum and Salsola collina was large.5 At different use of rotational grazing time, three plant populations of spatial variability in mid-grazing caused by random factors was lower, but was higher on maximum plant populations spatial variability. In different grazing systems, the main spatial heterogeneity of plant populations was relatively small, influenced greater by structural factors. There were three major plant species in the distribution of the main plaque mounted in the same treatments.6 Different use of the time in rotational grazing areas, there was a large nugget on soil total nitrogen, available potassium and organic carbon in early grazing area, and was a large maximum spatial variability in late grazing area. In different grazing system, spatial variability of the total nitrogen and organic carbon caused by random factors was continuous grazing area> rotational grazing area> control area, which of soil available nitrogen, total potassium and available potassium showed a maximum degree of the control area> rotational grazing area > continuous grazing area. Soil nutrients mainly affected not by random factors but by structural factors, spatial heterogeneity was small while spatial autocorrelation was large.7 At different use of time in the rotational grazing areas, the main plant species in early and late grazing area closely related to the spatial distribution of soil nutrients. In different grazing systems, the relationship between the main plant species and soil nutrients was rotational grazing area>control area>continuous grazing area. The relationship between main plant species and soil nutrients was Allium polyrhizum>Cleistogenes songorica>Stipa breviflora. Rotational grazing conditions were more conducive to remain stable on spatial distribution than that of continuous grazing conditions.8 Mid-grazing was more reasonable at different use of the time under rotational grazing, and in different grazing systems, rotational grazing condition was more favorable to sustainable development on Stipa breviflora steppe.更多还原