Abstract
To clarify the potential productivity and ecological characteristics of vegetation dominated by Stipa baicalensis, the aboveground phytomass, its seasonal dynamics, and vegetative composition were investigated in an ungrazed and unmown S. baicalensis-Prunus sibirica community as the native climax vegetation of the Songhen plain of Northeast China. The plant community was composed of 64 species. The maximum aboveground live phytomass of the community was 222.8 g DM m^<-2> at 130 days after starting growth (i. e., Aug. 18), after which the phytomass decreased. The dynamics can be described by an extended logistic model. The estimated crop growth rate (CGR) reached its maximum (3.9 g DM m^<-2> day^<-1> ) at 66 days after starting growth (i. e., June 15). Then the CGR decreased from that level, and showed a minus value from approximately 125 days after starting growth (i.e., Aug. 13). S. baicalensis constituted 26-36% of the community and was the most productive species among the components. P. sibirica amounted to 13 to 18%. The remaining production was primarily made up of Cleistogenes species, the other grasses, and Carex species. The Carex species was the earliest of the components to reach the maximum CGR.
