Abstract:

Exploring the spatiotemporal evolution patterns of Net Primary Productivity (NPP) of vegetation in Hutuo River Basin is of great significance for understanding and improving the surrounding ecological environment. Based on MOD17A3 NPP data, the spatiotemporal evolution of vegetation NPP in Hutuo River Basin from 2003 to 2022 was analyzed using methods such as univariate linear regression analysis and coefficient of variation. The vegetation NPP was combined with land cover types and terrain factors for zoning statistics. Results show that from 2003 to 2022, the average vegetation NPP in Hutuo River Basin ranged from 300 gC/(m²·a) to 400 gC/(m²·a). The maximum NPP peak occurred in 2020, reaching 828 gC/(m²·a), while the average NPP peak was in 2022, at 424.33 gC/(m²·a). Areas where vegetation NPP increased linearly from 2003 to 2022 accounted for 96.46% of the study area. The relative annual change rate of vegetation NPP mainly fell within the range of 20%-40%, and the long-term stability of vegetation NPP was characterized by low fluctuations. Among the land-cover types in the Hutuo River Basin from 2003 to 2022,agricultural land had the lowest average vegetation NPP,at 331.92 gC/(m²·a), whereas grassland had the highest, at 384.40 gC/(m²·a). Vegetation NPP increased with rising elevation and slope. In terms of aspect, planes featured the lowest vegetation NPP.

Key words: net primary productivity(NPP), Hutuo River Basin, spatiotemporal evolution, variation coefficient, zoning statistics