Effectes Of Rainfall And Grassland Use Alter On Productivity And Stability In Temperate Steppe Of Inner Mongolia

Plant community productivity as an important ecosystem function of grassland,to a large extent for human economic development and daily life to provide resources,to understand how community productivity to maintain stability in a changeable environment is a basic task of ecology.Factors influencing community stability include biotic and abiotic factors,among which species diversity is often associated with community stability,while on the other hand,ecosystem stability mechanisms respond significantly to climate change and grassland use,which may mask the impact of species diversity on stability.Therefore,it is of great significance to study the influence mechanism of grassland ecosystem stability,which is of great significance for exploring how the stability of grassland ecosystem responsive environment changes under future extreme weather events.To this end,we conducted a five-year precipitation and grassland use control experiment in temperate grasslands in Inner Mongolia.The effects of precipitation and land use pattern changes on plant community productivity,species diversity and stability were analyzed,and a structural equation model was constructed to explore the influence pathways of community stability,and the main results were as follows:（1）Species richness increased with the growth of precipitation gradient in the first three years（2017-2019）,and the trend in the last two years（2020,2021）is not obvious,there are differences between years.By distinguishing between different functional groups,it was found that the number of annuals/biennials increased in the last two years and did not change with treatment,this leads to interannual differences in the effects of precipitation on species richness.The Shannon-Weiner Index responds more to land use than species richness,and the impact of precipitation and land use on species diversity depends more on changes in species composition.（2）Long-term rain increase treatment promotes plant community productivity growth,rain reduction treatment reduces community productivity,inter-species characteristic differences functional groups and dominant species,common species and rare species responding differently to precipitation and land use,the productivity of perennial grasses and dominant species responded most strongly to rainfall.In addition,grazing promotes the productivity of dominant species compared to other land use patterns.（3）Species diversity and plant community productivity showed a positive positive correlation in previous years,indicating the overproductive effect of multi-species coexistence.In the last two years,because the community productivity was controlled by a small number of dominant species,and the increased species had less impact on productivity,resulting in a non-significant and negative correlation between diversity and productivity.（4）Precipitation indirectly promotes community temporal stability by affecting species stability and species asynchronity.Perennial grasses and dominant species play an important role in it,especially the stability of dominant species,which are more resistant to environmental fluctuations than other species,and the impact of land use type on community stability is weakPrecipitation has a significant impact on plant community productivity and stability in temperate grasslands in Inner Mongolia,the impact of grassland use and species diversity on community stability may be masked by other factors,and our study highlights the importance of other stability drivers other than species diversity in order to gain a more comprehensive understanding of the mechanisms that regulate ecological stability.