不同放牧强度对植物及啮齿动物作用的研究

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	不同放牧强度对植物及啮齿动物作用的研究
	刘伟
学位类型	硕士
导师	周立
	1996
学位授予单位	中国科学院西北高原生物研究所
学位授予地点	中国科学院西北高原生物研究所
学位专业	生态学
关键词	牧场管理放牧强度载畜量啮齿动物植被变化
摘要	本文从栖息地结构特征决定啮齿动物群落组成的角度出发，通过分析不同放牧强度下植物地上部分生物量、植被组成、种的多样性以及不同放牧处理间相似性系数的变化，初步探讨了小哺乳动物对植被变化的反应，得到如下结论：1.在不同放牧强度下，植物地上部分生物量随放牧强度的增加而减少；植被组成中，优良牧草的比例随放牧强的增加而降低，杂类草的比例随放牧强度的增加而升高。2.植物种的多样性指数随放牧强度的增加而升高。不同放牧处理间植物群落相似性系数从大到小的变化依次为：C·D → B·C……→A·E，即放牧扰动差异越小，其植物群落结构越相似，放牧是引起植被变化的主要原因。3.根田鼠种群密度随放牧强的增加而逐渐降低，其平均密度与放牧强度而呈显著的负相关(r=-0.8992，df=4，P<0.02)，平均死亡率与放牧强度呈显著的正相关(r=0.8343，df=4，P<0.05)，而种群补充量与放牧强度呈显著的负相关(r=-0.9162，df=4，P<0.02)。4.甘肃鼠兔种群受到重度、次重度放牧强度的严重影响而在这两个处理没有出现。其余处理中，随放牧强度的增加而逐渐减少，其平均密度与放牧强度呈显著的负相关(r=-0.9321，df=4，P<0.01)。5.高原鼢鼠的新土丘数在试验开始时相对较少，至试验结束时，重度、次重度放牧处理有大幅度的增加，且明显高于次轻度和轻度放牧处理，此时的新土丘数与放牧强度呈显著的正相关(r=0.9383，df=4，P<0.01)。总之，随着放牧强度的增加，植被的盖度和高度降低，伴随优良牧草的减少而杂草增多，草食性小型啮齿动物的食物多度和栖息生境发生越来越大的变化。其结果是随着放牧强度的增大引起适应隐蔽生境的根田鼠和甘肃鼠兔数量减少，以及喜食杂草地下根的高原鼢鼠数量增加。根田鼠和甘肃鼠兔个体小，采食量低，即使数量较高时对草场植被危害程度也较高原鼢鼠轻，因此，科学地选取适度的放牧强度，保持较高的优良牧草比例，是治理高原鼢鼠危害、发展持续畜业经济的生态学途径。
其他摘要	This paper based on community composition of rodent decided by habitat structure feature, and studied preliminarily response of small mammals to vegetative changes by analysing changes in vegetative composition, species diversity and similarity index between different grazing treatments, draw at following conclusion: 1. Plant aboveground biomass, the percentage of grasses, sedges and Potentilla fruticosa shrub (leaves, tender stem) decrease with increase of stocking intensity under different grazing intensity, the percentage of herbs increase with increase of stocking intensity. 2. Vegetative species diversity raise with increase of stocking intensity. The trends of plant community similarity index between different grazing treatments from large to small is: C·D → B·C → ……→A·E, that is to say, the smaller the differences between grazing disturbance are, the more similarity the plant community structure, the primary reason for vegetative change is caused by grazing. 3. Population density of root voles decline with increase of stocking intensity, their means densities are significant negative correlated with stocking intensity (r = -0.8992, df = 4, p<0.02), the others feature for population of root voles, such as body weight and sex ratio, is not correlated with stocking intensity. but population recruitments are significant negative correlated with stocking intensity. 4. Population of Gansu pika dose not occur in heavily-grazed, subheavily-grazed treatments since they are influenced dramatically by grazing. They decrease with increase of stocking intensity in the other grazing treatments. Means densities are significant negative correlated with stocking intensity (r = -0.9321, df = 4, p < 0.01). 5. The new mounds of zokor are relative poor at the begining of experiment, heavily grazed, subheavily grazed treatments significant increase at the end of experiment, and they are larger than sublightly and lightly grazed treatments, and the new mounds are significant positive correlated with stocking intensity. In a word, vegetative cover and height reduce, high quality grasses decrease, but herb increase, food abundance and habitat eviroment for herbivorous small mammals are changed dramatically with increase of stocking intensity. The consequence is that the population densities of Gansu pika and root voles lived in conceslment decline, and numbers of zokor eaten root of herb under round increase. So, to choose sciencely mordrate stocking intensity and maintain higher percentage of high quality grasses are a ecological way to aviod destory of zokor and develop economy of sustained animal hansbandry.
页数	33
语种	中文
文献类型	学位论文
条目标识符	http://210.75.249.4/handle/363003/3348
专题	中国科学院西北高原生物研究所
推荐引用方式 GB/T 7714	刘伟. 不同放牧强度对植物及啮齿动物作用的研究[D]. 中国科学院西北高原生物研究所. 中国科学院西北高原生物研究所,1996.

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