The Study On Colonization And Succession Of The Algal Crusts In Songnen Grassland

Plants initial germination,growth and produce fertile offspring reproduction process is called colonization.This process is influenced by many environmental factors.The research area is located in the Songnen grassland,previous studies on the biological crusts are mostly concentrated in the desert ecosystem,lack of relevant research in grassland ecosystems.To carry out experiments in Songnen grassland is necessary.Object of this study is algal crusts under vascular plant communities,due to the local climatic conditions and human disturbance,the biological crusts is basically stay in the stage of algal crusts.The study includes the following aspects: identification of species of cyanobacteria,investigation of the algal crusts colonize size,biomass,thickness,compare the algal crusts under different plant communities colonizing size,the effects of water,light and soil texture on the growth and development of the vaccination algal crusts.The experimental results show that: crusts under different vascular plant community types of algae composition is different,the species of cyanobacteria in different stages are also different,environmental factors can also affect the species and number of cyanobacteria in algae crusts.The formation of algal crusts,besides can rely on wind carry spores can also from the area already has the algae crusts colonize to bare to form,and the latter may be more rapid and widespread.In the Songnen grassland algal crusts under the Puccinellia tenuiflora communities colonizing fastest.Moisture and algal crusts growth showed a quadratic power relations;during the three kinds of soil,the thickness: sandy soil>Saline soil>forest soil;the biomass: aline soil >sandy soil>forest soil.Effects of light intensity on the algae crusts,the biomass: shade0%>shade75%> shade50%> shade25%,the thickness:shade 0%>shade25%>shade50%>shade75%.This study explores the algal crusts colonized manner and formation mechanism,analysis of environmental factors influence on vaccination crusts growth.