【作者】 高安社；

【导师】 许志信； 韩国栋； 赵萌莉；

【作者基本信息】 内蒙古农业大学 ， 草业科学， 2005， 博士

【摘要】 羊草草原是亚洲中部草原区特有的一类根茎禾草草原,对其在放牧条件下的草地健康研究有助于认识典型草原的整体状况,具有普遍意义。本项研究通过野外生态学调查,探讨不同放牧强度下羊草草原放牧生态系统健康诸因子的变化规律,分析不同放牧强度下羊草草原放牧生态系统健康诸因子的相关性。主要结论如下:在家庭牧场尺度上,根据离居民点的距离采用等距离样线梯度野外取样法,根据优势度利用逐步聚类分析方法,可以准确地将羊草草地的放牧强度划分出轻度放牧区和中度放牧区两个不同的等级;随着放牧强度的增大,羊草草原植物种类成分发生了显著变化,植物种数明显减少,根茎禾草比例下降,丛生禾草比例以中度放牧区为最多,小半灌木比例增加,反映了不同植物功能群对放牧强度的响应方式不同;中度放牧区植物群落的净生长量、盖度明显降低,主要植物的光合能力降低,而且地表的凋落物的数量大大减少,草地生态系统的稳定性变差;随着放牧强度的增大,土壤有机质、全钾、全磷、速效钾含量逐渐降低,土壤紧实度增大;土壤细菌、芽孢菌数量增加,放线菌、霉菌数量减少,自身固氮菌数量先增加后减少;草地生态系统健康评价的指标包括 4 个植被指标和 3 个土壤指标,即草群产量、草群盖度、建群种羊草地上净生产量、5 月凋落物量、土壤全磷、土壤有机质、0—20cm 土壤>0.05mm 砂粒含量倒数;利用上述 7个指标,采用模糊综合评价方法可将所研究的羊草草地的退化系列的健康水平定量地划分为健康、亚健康、不健康 3 个不同的等级;根据评价地段与不放牧的对照区的综合健康系数的分值大小,可以建立以下草地生态系统评价体系,即 I 健康、Ⅱ亚健康、Ⅲ 不健康和Ⅳ 崩溃 4 个等级,相应的综合健康系数分别为 1～0.76,0.75～0.51,0.50～0.26,0.25～0, 这一评价体系与草地基况评价体系非常相似,但是它包含了更加丰富的内涵。 本研究在国内首次采用野外生态学定量,结合模糊数学综合评价对草地健康状况进行系统评价,不仅填补了我国草地健康定量评估领域的空白,丰富了草地健康评价的内容,为我国草地健康指标体系的构建提供基础,而且对有关部门客观判断羊草草原的健康状况,特别是不同放牧强度对草地健康的影响状况和程度,制定切合实际的草地发展战略,推进草地畜牧业生产和环境保护具有现实意义。更多还原

【Abstract】 Leymus chinensis rangeland is one of the unique types of rhizomes grassland that appeared in middle-Asia. The study of its health assessment is benefit to understand the typical rangeland. Based on the ecological investigation, the dynamics of indicators related to range health were studied. The relationship among the indicators of range health under grazing intensity was also analyzed. The results showed:on family ranch scale, equity distance method was used to measure the vegetation. Based on the dominative value of vegetation, a precise grade of grazing gradients of Leymus chinensis grassland can be divided to light grazing area and moderate grazing area. As the increase of grazing pressure, plant species composition was changed. It’s showed a signified decrease, while the proportion of rhizome grass was also decrease. Bunch grass occupied most the proportion of the plants and semi-shrub increased in moderate grazing area, which indicated that different plant functional group have different ways responded to grazing. Both community biomass and coverage were decreased in moderated grazing area. Photosynthesis rate of the main species decreased too. The amount of litter was also decreased. Those were the cause of poor stability of grassland system. With the increasing of grazing pressure, total soil organic matter, total potassium,total phosphate and available potassium were decreased, while soil bulk density increased. The number of soil bacteria、bacillus increased,and ray fungi、fungus decreased. The number of self nitrogen-fixing bacteria increased then decreased as the increased of grazing pressure. The indictors used for of range health assessment included 4 vegetation indictors and 3 soil indictors. There were: community productivity, total base coverage, net productivity of main species-Leymus chinensis, litter amount at May, total soil phosphate, soil organic matter, and the reciprocal of 0—20cm soil particles the diameter is greater than 0.05mm. By using the above 7 indicators, fuzzy integrative assessment method was adopted, thus, the health level of degraded grassland can be determined to health, sub-health, no-health. According to the value of range health of the degraded zone and the reference, a system can be established that is, I. Health, II. Sub-health, III. No-health, IV. Collapse. The coefficient for each level were, 1～0.76,0.75～0.51,0.50～0.26,0.25～0. This system is similar to range condition, but covered more contents. By using the quantity ecological data, combined with the fuzzy mathematics assessment method to evaluate the range health level is the first both domestic and aboard. These not only fit the gap of range health assessment in China, richen the contents of range health evaluation and provided a basic for range health indictor’s framework establishment, but also giving a good guide for judge the health level of Leymus chinensis, especially in range management, which is benefit to piratical grassland strategies development, grassland animal husbandry and environment production.更多还原