PA-012:

Characterization of degradation of wetland plant communities on floodplain in typical steppe region of Inner Mongolia Plateau

Aims River floodplain meadow is the most productive sites of biological, but due to excessive grazing, the vast majority becomes degraded meadow. In this paper, we compared fenced (non-grazed) and grazed sites within the wetland. We present results of analyses of changes of vegetation in a Xilin River basin (Inner Mongolia) wetland meadow. Our findings is good information for the restoration of degraded wetlands and important for the restoration and management of degradation of wetland
Methods We carried out vegetation and soil characteristics studied include plant community composition, aboveground biomass, plant height, internode length, main species leaf length and width, plant community root biomass and root distribution, soil moisture content, soil bulk density, soil microbial biomass, carbon and nitrogen content.
Important findings Grazing affects plant dominant species significantly by gradually replacing original wetland plants with more drought-resistant ones. It also significantly reduces the aboveground and belowground biomass; Plants in a degraded wetland meadow are smaller thus resulting in the decline in community productivity; Grazing also causes the drop in soil moisture in a wetland below the fenced sites. In the low flood plain, soil moisture and root biomass both increase with increasing soil depth. However, in the high flood plain, soil moisture does not change with soil depth and is similar to that of the typical steppe; Soil bulk density increases as a result of grazing and trampling by animals. Overall, soil becomes compacted due to these activities; In the high and low floodplain wetlands, the changes of soil microbial biomass carbon and nitrogen between fenced and grazed site are varied. In the low floodplain wetlands, grazing makes microbial biomass increased, while in the high floodplain wetlands, grazing makes significant reduction in microbial biomass carbon and nitrogen.

keywords:degradation characterization,degradation mechanisms,wetland degradation,Xilin River