The Effects Of Population Size And Density On Reproductive Success Of Circaeaster Agristis Maxim

The research of reproductive success is a corn concept in reproductive ecology of plant. In Allee effect, there is a positive relationship between plant fitness and population or density. Small or sparser population may suffer the risk of extinction. Circaeaster agristis Maxim, a national second grade protective plant, distribute narrowly in china. The fragmatation and isolation of habitant by anthropogenic activity can risk the species’s persistence. To explore the relationship between population size, density and reproductive success of Circaeaster agristis Maxim, we did this research in Wanglang national natural reserves during2010and2011. We measured population area, density and population size of different populations of Circaeaster agristis Maxim, also we measured stem hight, leaf number, flower number, seed number and seed set of Circaeaster agristis Maxim plants. The results showed as follows:1The relationship between population size and population density was significantly positive, which may be correlated which the quality of habitant.2The relationship between plant size, reproductive success and population size was not significant.3There was a negative relationship between population size and reproductive success in2010. But There was no significant relationship in2011. When excluding three most dense population in2010, also there was no significant relationship between population size and reproductive success. This may be caused by density effect.4We used regression analysis to discuss the relationship brtween population density, flower number per plant and its reproductive success. There was a significant positive relationship between plant size(flower number per plant) and seed number per plant, the same result as the Pearson corerelation analysis. There was a significant negative relationship between population density and seed number per plant, which indicated that when the plant size was in the same leval, there was also a negative relationship between population density and seed output per plant. Also, There was a significant positive relationship between plant size(flower number pet plant) and.seed number per plant.the same result as the Pearson corerelation analysis. There was a significant negative relationship between population density and seed set per plant, which indicated that when the plant size was in the same leval, there was also a negative relationship between population density and seed set per plant.