沙坡头地区固定沙丘一年生植物小画眉草种群动态研究

通过对一年生草本植物小画眉草（Eragrostis poaeoides)种群动态的研究，可以看到小画眉草的萌发和生长以及数量动态对于降水的强烈依赖，使得草本植物的萌发具有成批性，小画眉草有4批出苗。开始出苗后由于连日高温干旱，致使第一批苗全部死亡。之后，由于降水较多县相对较集中，出苗、生长发育与自疏死亡成连续过程，观察到的是其净结果。由于水分对种群的制约，种群间对水分的竞争必然导致自疏现象，一年生草本植物的存活曲线属于C型，生活史对策明显表现为r-对策。r-对策种群往往出现在群落演替的早期阶段。

Population Dynamic of Annual Plant Eragrostis poaeoides in Fixed Sand Dune in Shapotou Area

The germination, growth, development and population of \%E. poaeoides\% are stro ngly dependent on the precipitation. The plants germinated group by group and in patches. In 1994, there appeared 4 germinations. Because of the continuous drou ght after the germination, the first young seedlings had died totally sooner. La ter on, since the precipitation increased, their germination, growth, developmen t and natural self-thinning became normal and formed a continuous process. The observed and measured data are the net increment of the process. Water limitatio n and competition of its use between plants must result in population self-thin ning. The C-pattern survival curve of the annuals implies that their life strat egy belongs to r-strategy. r-strategy species appear after occupy the earlier st ages of succession.