【作者】 葛庆征；

【导师】 张卫国；

【作者基本信息】 兰州大学 ， 草坪生物学， 2013， 硕士

【摘要】 2009年7月20日,甘肃省甘南州玛曲县及实验区阿孜畜牧试验站发生了极端降水事件,3个多小时降水量高达92.8mm。在此背景下,本研究于2008年至2011年,就高寒草甸植物群落、高原鼠兔(Ochotona curzniae)(?)中群在极端降水前后的动态及其相互关系进行了研究,主要研究成果如下：1.受极端降水的影响,植物群落高度和盖度呈现先增加后降低的趋势,物种多样性表现为先降低后增加的趋势；生物量也显著低于其他年份。2.高原鼠兔种群密度一般为单峰型曲线,而放牧处理样地则不同,降水当年呈现双峰型曲线,8月份降到最低点(P<0.01),10月份出现一定的回升趋势。3.高原鼠兔种群体重的月变化受极端降水的影响较大,2009年8月降水后,与其它三年同期均存在显著差异(P<0.05)；体重年变化呈单峰型曲线,最高值出现在2010年,受种群密度制约以及外界环境条件的影响,2011年高原鼠兔平均体重降到最低值。4.高原鼠兔种群的存活率在2009年7月由于极端降水的影响降到最低值,与其他三年同期相比存在显著差异(P<0.05).2010年高原鼠兔存活率明显回升,而后趋于稳定,与“密度制约依赖理论”相吻合；5.高原鼠兔种群的性比除2010年第一次标记时成体性比受极端降水的影响较为严重,明显偏离1：1(P<0.01),其他各时期性比逐渐趋于1：1；6.极端降水、植物群落与高原鼠兔种群密度之间存在着密切的相关性。极端降水首先作用于植物群落,改变了植物群落高度、盖度、多样性,随着植物群落各指标的变化,高原鼠兔种群亦随之发生相应的改变,从而引起种群密度的波动。本研究结果表明,高原鼠兔种群动态受密度制约理论的控制：极端降水导致高原鼠兔种群数量急剧下降,但降水后第一年和第二年,鼠群数量则有较大程度的回升。因此,在高原鼠兔种群数量回升的初期实施有效的控制措施,可以收到事半功倍的效果。更多还原

【Abstract】 The extreme precipitation happened on July20,2009, during which the amount of precipitation was92.8. mm during three hours. Under this background, the dynamics of plant communities and plateau pika (Ochotona curzoniae) population, and the relationship between them were investigated from2008to2011, before and after extreme precipitation. The main results are as follow:1. Affected by the extreme precipitation, plant height and coverage increased at first and then, reduced, while the species diversity showed an increasing trend at first and then decreased. Aboveground biomass also decreased significantly compared with other three years.2. Population density of plateau pika showed a unimodal pattern in general. While in grazing area, population density of plateau pika manifested a bimodal curve in the year of extreme precipitation, The lowest point appeared in August (P<0.01), it then had a certain degree of rebound in October.3. The extreme precipitation had a great effects on monthly body weight of plateau pika, the data in August2009differed significantly from other three years (P<0.05). The yearly fluctuation showed a unimodal pattern, and the highest value appeared in2010. Restricted by density-dependent factors and environmental change, the body weight dropped to lowest value in2011.4. Because of affected by the extreme precipitation, survival rate of the plateau pika populations reduced to the lowest point in July2009, and had a significant differences (P<0.05) compared with the same period of other three years. Survival rate rised again in2010, and then, tend to be stable. This patterns consistent with " density-dependent" theory.5. The sex ratio of plateau pika was influenced greatly by extreme precipitation in2010, which deviated significantly from1:1. The sex ratio of other years, however, gradually tend to be1:1.6. There existed a closely correlations between extreme precipitation and plant communities、population density of plateau pika. Extreme precipitation first play an important role on plant communities, changing the height of plant communities, coverage, diversity, and vegetation biomass. With the changes of each plant community index, consequently, the population density of plateau pika change too.These results suggested that the population density of plateau pika was restricted by density-dependent theory:the extreme precipitation resulted in great decreasing in population number of plateau pika, but it rised again after1and2years of precipitation. Therefore, to carry out effective control measures will get twice the result with half the effort.更多还原