Temporal Dynamics Of Plant Diversity, Aboveground Productivity, Species Composition And Turnover In Inner Mongolia Temperate Grasslands

Researches on ecosystem functions and processes are important parts of ecology, in particular, the spatiotemporal dynamics of the relationship between plant species diversity and productivity, community dynamics and species turnover. Here we re-sampled twenty-three sites in the grasslands of Inner Mongolia in 2007,2012-2015, we have explored the species diversity-ANPP relationship over time and their relationship with climate change. The results show that ANPP has higher temporal variation (CV= 42.9%) than SR (CV=17.6%), H’(CV=10.7%) and J (CV=4.88%). Both ANPP and plant diversity, the inter-annual variation of desert grassland are higher than those of typical steppe and meadow steppe. The relationship between productivity and diversity across the whole study region maintains the similarly linear pattern. The inter-annual fluctuations of climatic variables have no significant effects on the plant diversity and ANPP. We have analyzed the plant community functional group composition varying in different grasslands with time. The results reveal that: the pattern of the relative proportion of biomass in community is grass>forbs>AB>shrub, but the pattern of inter-annual changes in relative proportion of biomass is completely opposite. Biomass of perennial grasses is the largest, but the variation of biomass is the minimal. The precipitation and temperature have no significant effects to the relative biomass except AB. But the species richness of perennial grasses and forbs are positive to the precipitation and negative to the temperature in the growing season. Fluctuation of AB over time is the biggest, and the relative biomass of AB is negatively correlated with precipitation. And we have calculated the species turnover rate with time. There is on different in three type grasslands in species gain rate, species loss rate and species turnover rate. Species turnover rate changes little with time, increases with species richness. Climate modifies the species turnover by enhancing the species gain rate and reducing the species loss rate.