Evaluation of Land Degradation Neutrality in Inner Mongolia Combined with Ecosystem Services

Abstract

Currently, the internationally recognized land degradation neutrality (LDN) effort is evaluated using three indicators: land use/cover, land productivity, and carbon stocks. However, these three indicators may not completely capture the factors influencing LDN, and some evaluation rules are not in line with the land restoration goals of China. Therefore, this study introduces the ecosystem service value (ESV) indicator, assesses the differences in connotation and evaluation methods between ESV and LDN, and puts forward an evaluation rule that integrates their advantages, so as to carry out an evaluation of LDN in Inner Mongolia. The conclusions are as follows: (a) The ESVs of the Inner Mongolia Autonomous Region in 2000, 2005, 2010, 2015, and 2020 were USD 287.49, 286.04, 285.72, 286.38, and 287.90 billion, respectively, which presents a slight trend of decrease and then increase over time. (b) The modified LDN evaluation rule mainly includes the following changes to the LUCC evaluation rule: (1) the original degradation of cropland to grassland is considered as restoration, (2) water bodies participate in the transformation evaluation between land use types, and (3) the evaluation of transformed secondary land use types is added. The evaluation of net primary productivity (NPP) and soil organic carbon (SOC) still follow the method formulated by the United Nations Convention to Combat Desertification (UNCCD). (c) The proportion of degraded, stable, and restored land area within the LUCC were 11.31%, 77.34%, and 11.35%, respectively. The proportion of restored area is greater than the proportion of degraded land, which indicates that LDN has been achieved in Inner Mongolia according to the LUCC evaluation. The areas of degradation, stability, and restoration for NPP accounted for 0.10%, 40.52%, and 59.38% of the total area, respectively, with the restored area being much larger than the degraded area. The areas of SOC degradation, stability, and restoration accounted for 13.06%, 74.82%, and 12.11% of the total area, respectively, and the degraded area was slightly larger than the restored area. (d) The LDN evaluation results showed that the proportions of degraded, stable, and restored areas were 21.80%, 27.25%, and 50.96%, respectively. From these results, it is clear that Inner Mongolia has achieved the LDN target. Compared with the rules formulated by the UNCCD, for the LDN evaluation results implementing the modified rule, the proportion of degraded land increased by 2.44%, the proportion of stable land decreased by 1.52%, and the proportion of restored land decreased by 0.92%. In the future, Inner Mongolia should strengthen the implementation of a series of ecological restoration projects to obtain greater ecological benefits.