Assessment of ecological environment quality and recommendations for management in Helan mountain national nature reserve, Ningxia

Helan Mountain region serves as a crucial ecological security barrier in northwest China. Excessive mining has severely impacted the ecological environment, making it urgent to assess ecological quality changes for better governance. Utilizing long-term MOD17A3 remote sensing data, along with DEM, vegetation type, and land use data, this research quantitatively examines the spatiotemporal variations in vegetation Net Primary Productivity (NPP) within the Helan Mountain National Nature Reserve in Ningxia over the period 2001 to 2020, assessing alterations in ecological environment quality. The results indicated: (1) The average NPP exhibited a declining trend from southwest to northeast. (2) Throughout the study duration, the mean annual NPP exhibited a variable upward trend, accompanied by an average yearly growth rate of 1.66 gC/m²/yr. (3) Vegetation NPP exhibited spatial heterogeneity. The southwest region had a marked upward trend, the northeast region a moderate increase, while some areas experienced a decline due to human disturbances. The findings can inform decisions on ecological restoration and regional management across different areas of Helan Mountain.