The Relationship Between Species Diversity And Productivity In Restoration Succession Process Of Degradation Grazing Meadows In The Songnen Plain Of China

The relationship between species diversity and productivity is an important scientific problem in realm of ecology. Most of the research about the relationship between species diversity and productivity on grassland ecosystem was conducted in field simulation, while it is fairly rare to make a long-term observational research for grassland in nature. The experiment is conducted on two plots on different processes of natural ecological restoration (by prohibition of grazing), which have been fenced, one since 2001, the other since 2006. From the year 2007 to 2010, we have observed and measured the basic quantitative characteristics of grassland for four years. And we have analyzed the relationship between plant biodiversity and productivity, the contribution to the productivity of communities in different species and function groups, and the effect on the relationship between plant diversity and productivity by the change of climate conditions. The objective of the experiment was to clarify the relationship between biodiversity and productivity in process of degraded restoration successions in the Songnen Plains, and to reveal the regulation of growth and decline of different species and functional groups in communities. These would offer a theoretical guidance to the restoration practice of meadow ecosystem. The basic conclusions are as follows:(1) In the process of restoration succession, the change of species richness was not significant. As the succession forwards, the relation between the species diversity index and ANPP becomes monotonic priority, that is, the maximum productivity occurs at the intermediate levels of species diversity.(2)The volume of the aboveground biomass depends on the contribution of individual species, such as Salsola collina Pall, Artemisia scoparia Wald. et Kit., Chloris virgata Swartz., which are the major contributors to the gross productivity. As the succession forwards, the major component of the communities has gradually succeeded to Leymus chinensis plus Artemisia scoparia communities types.(3)As the succession forwards, the plant functional groups shows that there is a significant between the AB and PR productivities of communities(P<0.05), which would enhance the communities stability. And AB and PR are the most important functional groups in general.(4) Under drought condition, the different types of plant functional groups have differences in sensitivity for environmental condition and response of functional groups forms by complementary relationship, which enhances the ecosystem stability.