*Article* **Comparative Assessment of Grassland Dynamic and Its Response to Drought Based on Multi-Index in the Mongolian Plateau**

**Yanzhen Zhang 1,2, Zhaoqi Wang <sup>3</sup> , Qian Wang <sup>4</sup> , Yue Yang <sup>5</sup> , Yaojun Bo <sup>1</sup> , Weizhou Xu 1,\* and Jianlong Li 2,\***


**Abstract:** This study applied grassland related multi-index and assessed the effects of climate change by investigating grassland responses to drought. This process was performed to study grassland vegetation dynamic accurately and evaluate the effect of drought in the Mongolian Plateau (MP). The spatial–temporal characteristics of grassland dynamic in terms of coverage (Fv), surface bareness (F<sup>b</sup> ), and net primary production (NPP) from 2000 to 2013 were explored. We implemented the maximum Pearson correlation to analyze the grassland vegetation in response to drought by using self-calibrating Palmer Drought Severity Index (scPDSI). Results show that F<sup>v</sup> and NPP present an increasing trend (0.18 vs. 0.43). F<sup>b</sup> showed a decreasing trend with a value of −0.16. The grassland Fv and NPP positively correlated with scPDSI, with a value of 0.12 and 0.85, respectively, and F<sup>b</sup> was −0.08. The positive correlation between F<sup>v</sup> and NPP accounted for 84.08%, and the positive correlation between Fv and scPDSI accounted for 93.88%. On the contrary, the area with a negative correlation between F<sup>b</sup> and scPDSI was 57.43%. The grassland in the MP showed a recovery tendency. The increase in grassland caused by positive reaction was mainly distributed in the middle of Mongolia (MG), whereas that caused by counter response was mainly distributed in the east and west MG and northeast Inner Mongolia autonomous region of China (IM). The relevant results may provide useful information for policymakers about mitigation strategies against the inverse effects of drought on grassland and help to ease the losses caused by drought.

**Keywords:** the Mongolia Plateau; grassland degradation; vegetation coverage; surface bareness degree; self-calibrating Palmer Drought Severity Index (scPDSI)
