From the increase of soil patchiness scale in the thicketization of steppe,it is suggested that the transition from steppe to thicketization-steppe dominated by Caragana microphylla patches could be irreversible once this threshold is passed.

Comparison on the characteristics of main nutrient element contents of mountain shrubby-grassland and sowed Dactylis gomerata grassland in the valley area of Lhasa River;