In order to explore the response of sagebrush deserts grassland community structure and biomass component allocation pattern of Seriphidium borotalense to degradation under different degradation degrees， the plant community characteristics， plant community diversity index， species diversity characteristics， and modular biomass allocation patterns of S. borotalense desert grassland in undegraded （UD）， lightly degraded （LD）， moderately degraded （MD）， and highly degraded （HD） areas were measured and analyzed. It was found that with the increase of degradation degree， the community height， coverage and aboveground biomass decreased significantly， and the density increased significantly （P<0.05）. The Patrick index did not change， and the other diversity indexes decreased significantly. The height， coverage and aboveground biomass of S. borotalense decreased significantly （P<0.05）， and the density reached the maximum at LD， but no S. borotalense was found at HD. The distribution of stem and leaf components such as plant height， stem length and leaf weight decreased significantly （P<0.05）， and the distribution of root components such as root weight， root diameter and root weight ratio reached the maximum at LD. Redundancy analysis showed that community coverage was the most critical environmental factor driving the component allocation pattern of S. borotalensei. To sum up， S. borotalense responded to grassland degradation by optimizing the component allocation pattern， and the optimization threshold was between LD and MD.

Sagebrush desert  /  Plant community characteristics  /  Seriphidium borotalense  /  Modular biomass allocation patterns