Ecological adaptation strategies of annual plants in artificial vegetation-stabilized sand dune in Shapotou Region

查看全文 作　　者：ZHANG Jingguang LI Xinrong WANG Xinping WANG [1]Gang 机构地区：[1]Shapotou Desert Experimental Research Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chine Academy of Sciences, Lanzhou 730000, China Shapotou Desert Experimental Research Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chine Academy of Sciences, Lanzhou 730000, China Shapotou Desert Experimental Research Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chine Academy of Sciences, Lanzhou 730000, China Shapotou Desert Experimental Research Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chine Academy of Sciences, Lanzhou 730000, China 出　　处：《Science China Earth Sciences》索引2004年第47卷第z1期,共11页 基　　金：supported by the National Natural Science Foundation of China(Grant No.90202015);Innovation Study Project from Chinese Academy of Sciences(Grant Nos.KZCX3-SW-324,KZCX1-09);State Key Project for Basic Research'the Process of Desertification and Its Control in the Northern China'(Grant No.G2000048704). 摘　　要：Taking annual plant Eragrostis poaeides in the artificial vegetation-stabilized sand dune in the Shapotou Experimental Research Station as example, study has been done on the adaptation strategies of annual plants to random environment through fixed quadrat observations of population changes and fixed plant determinations of individual growth, seed germination,population dynamics, spatial distribution pattern of population, competition and regulation. During the growing season, the survival rate of annual plants depends on the precipitation intensity and precipitation duration which activate the germination of seeds. The optimal germination strategy of annual plants in this habitat during the growing season appears as continuous germination under suitable conditions. Such continuous germination is an adaptive characteristic of annual plants to random environment. In addition, the variation processes of population size and regulation mechanism of E. poaeoides are studied. Statistical results of natural population in four consecutive years show that water condition in the habitat is the leading factor affecting the population dynamics of E. poaeoides. During the establishment period E. poaeoides had a higher death rate, but in the middle to later period they could survive stably. Due to the limitation of soil moisture, the competition among individuals for water inevitably led to self-thinning phenomena. Under very arid condition, the survival curve of annual herbs entirely appears as Deevey Ⅲ type (C type), but under relatively adequate precipitation condition, the survival curve appears as intermediate type. The strategy of life history obviously appears as r-strategy. Plant species of r-strategy often occurs in the early succession stage of the communities. In the relatively adequate and evenly-distributed rainfall years, E. poaeoides population exhibited a density-dependent, i. e., survival rate increased with decrease in population density. The main pattern to regulate the population number for the intraspecific competition is to regulate the highly variable initial density into a final density with narrow variation range. 关 键 词：Shapotou region, ERAGROSTIS poaeoides, ECOLOGICAL ADAPTATION strategy.