The researchers studied changes in grassland vegetation coverage in Gannan Prefecture from 2001 to 2011. They used satellite data and on-the-ground observations to create models for vegetation coverage. The study found that grassland vegetation coverage increased over the 11-year period, with the highest coverage in 2005. The western and southwestern areas had better vegetation coverage than the eastern area. Overall, the grassland in Gannan Prefecture transitioned from high to even higher vegetation coverage levels during the study period.