Analysis of grassland degradation in Gansu Province based on two grassland surveys

Grassland degradation due to the impacts of overgrazing and climate change is a common phenomenon. Therefore, grassland surveys have become an effective strategy for understanding the degree of grassland degradation. In the present study, total grass yield, edible grass yield, and vegetation coverage were selected as the evaluation indices of grassland degradation in Gansu Province, determined based the data collected during two surveys: the first survey in the 1980s and the second from 2014 to 2017. According to the national standards of grassland degradation, combined with the expert scoring method, we used inverse distance weighted interpolation to evaluate the degradation indices and explore the spatial distribution of each degradation grade in the study area. The area of the degraded grassland was 1.79 × 10⁷ ha, accounting for 69.65% of the total grassland area in Gansu Province. Of this, 23.81% was slightly degraded, 47.27% moderately degraded, and 28.92% severely degraded. The most degraded grassland types were alpine desert steppe and alpine steppe, whereas the least degraded grassland types were mountain meadow meadow and temperate desert steppe. These findings advance our understanding of the current status of grassland degradation in Gansu Province.