Early warning indicators of grassland degradation in inner Mongolia

Backgroung: With the implementation of the Household Production Responsibility System in China almost 30 years ago, obvious spatial heterogeneity has developed over rangeland. Methods: We examined lifeform functional groups over 5 years on household ranches in different grazing utilization rate (30%-95%) ecosystems in Inner Mongolia to identify the early warning indicators of grassland degradation. Results: The results showed that a similar grassland utilization threshold occurred in different types of steppe, with 78-89% utilization for meadow steppe, 81-89% for typical steppe and 70-85% for desert steppe. The vegetation composition above these utilization thresholds did not show obvious signs of degradation; therefore, the risk of degradation was difficult to determine. The spatial threshold (WD: L) had a value of 31.40:100 for meadow steppe, 8.53:100 for typical steppe and 42.21:100 for desert steppe. Conclusion: Land managers cannot easily determine the risk of degeneration according to the vegetation composition or function group. So the spatial threshold is important for implemented strategies to prevent degradation, and our study provides new insights to improve the management and restoration of degraded grassland in Inner Mongolia.