Species diversity in grassland plant communities

The dynamics of growth, mortalityreproduction and the size and spatial distributions of genets of Anthoxanthum alpinum，Deschampsia flexuosa, Nardus stricta，Festuca rubra were investigated in a mountain grassland of the Krkonose Mountains in the CzechBased on the field and experimental resultsmaintenance mechanisms of species and genetic diversity theoretically调查。extracted DNA from about 2000 sampled leaves and identified size and spatial position of eachindividual genet by using a DNA-RAPD method. We found 450-750 genets per 1mrubra. Its mean genet size was about 22 cm y D12 y D1. The clonal growth rate of Festuca rhizomes was0.2-0.3/year. The mortality rate of shoot was also 0.2-0.3/year. It is almost impossible to measuregenet natality in a non-destructive way. Therefore我们开发了一个新模型来估计基因natality from the above-mentioned demographic parameters。这是一个suggested that the Festuca population can persist stably if the genet natality rate isyear. The clonal growth and mortality rates of Festuca shoots showed only小变量in the field. Genet natality may be most greatly affected by环境variations When the clonal growth and mortality rates of Festuca shoots are in the range of thevalues given above，the Festuca shoot population is stable even if the genet natality is greatly varied due to环境variations.它也可以revealed that genetic structure played a more important role这里有关于grassland plant community studied的其他条款。

The dynamics of growth, mortality, reproduction and the size and spatial distributions of genets of Anthoxanthum alpinum, Deschampsia flexuosa, Nardus stricta, Festuca rubra were investigated in a mountain grassland of the Krkonose Mountains in the Czech Republic. Based on the field and experimental results, maintenance mechanisms of species and genetic diversity were theoretically investigated. We extracted DNA from about 2000 sampled leaves and identified size and spatial position of each individual genet by using a DNA-RAPD method. We found 450-750 genets per 1mィイD12ィエD1 of Festuca rubra. Its mean genet size was about 22 cmィイD12ィエD1. The clonal growth rate of Festuca rhizomes was 0.2-0.3/year. The mortality rate of shoot was also 0.2-0.3/year. It is almost impossible to measure genet natality in a non-destructive way. Therefore, we developed a new model to estimate genet natality from the above-mentioned demographic parameters. It was suggested that the Festuca population can persist stably if the genet natality rate is 4-10genets/1mィイD12ィエD1 year. The clonal growth and mortality rates of Festuca shoots showed only small variations in the field. Genet natality may be most greatly affected by environmental variations. When the clonal growth and mortality rates of Festuca shoots are in the range of the values given above, the Festuca shoot population is stable even if the genet natality is greatly varied due to environmental variations. It was also revealed that genetic structure played a more important role than competition between species for the dynamics of grassland plant community studied here.