Influence Of Biodiversity, Species Identities, And Soil Fertility On The Experimental Community Productivity Of Sub-alpine Meadow

The maintenance of biodiversity is affected by many factors, and ecosystem functioning is largely controlled by species composition (biological characteristics of species). The relationship between biodiversity and ecosystem functioning has a considerable dispute, and has emerged as a major scientific issue today. In order to reveal the ecological mechanism of plant community productivity performance, we, using pot experiments, explore the influence of biodiversity, species identities, and soil fertility on the plant community productivity.The results of research are as follows:In 2007 and 2008, the influence of the species diversity on the aboveground biomass were not significant under low (F0) and mid (F1) fertility level; species diversity and aboveground biomass was positively correlated in the high fertility level (F2) of 2007. However, species diversity and aboveground biomass was negatively correlated in 2008. In 2009, species diversity and aboveground biomass showed a positive correlation, species diversity has a very significant impact on biomass, and aboveground biomass increases with the increase of species diversity significantly; but comprehensively considering, under different soil fertility level, species diversity and aboveground biomass were positively correlated; with the increase in fertility, regression coefficient of the species diversity and aboveground biomass were reduced. In the low (F0), mid (F1) and high fertility level (F2), the impact of the species diversity on aboveground biomass was not significant. Therefore, we can know that there is no causal relationship between species diversity and community productivity, and the correlation (positive correlation and negative correlation) exists just because of being influenced by available resources (natural resources and artificial fertilization).When taking the species identity into account, the impact of fertility level on the aboveground biomass of plant communities is very significant, and the impact of species diversity on aboveground biomass of plant communities is not obvious; a separate analysis of the contribution of different species and planting density to aboveground biomass, we found that Z20, P20, P30 and E30 had significant positive effects on the plant community productivity in mono-culture (Z, P and E represent Festuca sinensis, Elymus Nutans and Roegneria Nutans respectively; and 10,20 and 30 refers to the number of plant species respectively; such as P20 indicate there are 20 Elymus Nutans in each tray). In mixed culture, Z10P10,Z10P20,Z20P10,E10Z10,E10Z20 and E20Z10 have significant impacts on the aboveground biomass, and other species and planting density had no effect on aboveground biomass.As a result, fertility levels play a decisive role in the aboveground biomass of plant communities, aboveground biomass of plant communities changes significantly under different soil fertility level, the contribution of species attributes to biomass varies with the changes of species and planting density. In short, there is no necessary link between the plant community productivity and species diversity, and it doesn't have an essential association with species diversity, but have a relation with the soil fertility and species attributes.