Study On The Difference Of Soil Respiration CO₂ Flux And Biomass Response In The Changbai Mountain Tundra Under Herbal Invasion

At present,the global climate has changed the main trend of warming,and the response of high latitude and high altitude areas to global warming is particularly significant.Under the background of global change,land surface temperature,soil temperature,soil moisture,soil physical and chemical properties and soil microorganisms have also undergone a series of changes.The vegetation of Changbai Mountain tundra also has different forms of response,because of the different degree of invasion of herbaceous plants and the different types of herbaceous invasion.The typical communities of the tundra belt in Changbai Mountain are mostly mixed communities of Rhododendron chrysanthum,Vaccinium uliginosum,Dryas octopetala Carex siderosticia and forbs.Because of different vegetation growing environment,there are differences in vegetation types.In the tundra zone of Changbai Mountain,there are various types of changes in the plant.There are three forms in general,including the forbs invasion of the Rhododendron chrysanthum community,the Deyeuxia angustifolia invasion of the Rhododendron chrysanthum community,and the Carex siderosticia invasion of the Vaccinium uliginosum-Dryas octopetala community.In this study,the typical vegetation change series in the Changbai Mountain tundra were taken as the research objects to study the law of soil respiration under different degrees of herbaceous invasion.In different vegetation communities,the distribution of aboveground and underground biomass was studied by comparing the differences in aboveground and belowground biomass.This study specifically includes the following three research issues: Comparison of dynamic changes in soil respiration under different herbaceous invasive shrub communities;To explore the relationship between soil greenhouse gas flux and environmental factors;To study the biomass differences of different communities.It also predicts the change of carbon storage in the Changbai Mountain tundra and provides a basis for the change of carbon storage in the tundra under global climate change.The main findings are as follows:(1)With the deepening of the invasion,the total biomass of all plots increased in(1)With the deepening of the invasion,the total biomass of all plots increased in turn.Comparing the average values of the vegetation biomass in the three plots,the order of the average biomass was ranked as follows: A>B>C.The vegetation biomass of the forbs invasion of the Rhododendron chrysanthum community was the largest,the Deyeuxia angustifolia invasion of the Rhododendron chrysanthum community was the second,and the Carex siderosticia invasion of the Vaccinium uliginosum-Dryas octopetala community was the smallest.The total vegetation biomass of the Rhododendron chrysanthum community is greater than Vaccinium uliginosum-Dryas octopetala community.(2)With the deepening of invasion,the soil CO2 flux increased in turn.The soil CO2 flux in all three plots showed obvious seasonal dynamic changes,with peak values appearing in August.Comparing the mean values of soil CO2 fluxes,it can be seen that the order of descending order is B>A>C.The soil respiration of the Rhododendron chrysanthum community is greater than Vaccinium uliginosum-Dryas octopetala community.(3)Through an exponential fitting of 0-10 cm soil temperature and soil CO2 flux,we found that the fitting results are good,and there is a clear positive correlation with a high correlation coefficient.Analysis of Q10 in each plot showed that soil respiration in each plot was more sensitive to the increase in soil temperature.