Changes in Holdridge Life Zone diversity in the Xinjiang Uygur Autonomous Region (XUAR) of China over the past 40 years

The Holdridge Life Zone model, Shannonʹs Entropy Index and Simpsonʹs Diversity Index were used to study the dynamics of vegetation distribution over the past 40 years in the Xinjiang Uygur Autonomous Region (XUAR), China. The results indicated that Holdridge Life Zone diversity was highest in the 1960s, dramatically decreased in the 1970s, and then gradually increased in the 1980s and 1990s. From the 1970s, the environment in XUAR seemed to be increasing in stability, as characterized by a reduction in the number of days of sandy dust storm activity in the 1990s, and an increase in temperature and precipitation leading to an increase in water flow in some rivers. It is possible that both changes in human activities and positive climate change contributed to the Holdridge Life Zone diversity dynamics and more stable environment in XUAR.