A study on the impact of climate change and human activities on vegetation NPP in the Central Yunnan urban agglomeration from 2000 to 2020

Net primary productivity (NPP) is a key indicator of ecosystem carbon sequestration and response to environmental changes. This study used the CASA model with meteorological, NDVI, and land use data to estimate the NPP of the Central Yunnan Urban Agglomeration from 2000 to 2020. Key findings include an average NPP of 608.02 gC/m2 with an annual increase of 1.33 gC/m2 and notable seasonal variation. Spatially, NPP exhibited a "high edge–low center" pattern, with 54.51% of the area remaining stable. Moderate and high fluctuations accounted for 52.30% and 21.95% of the region, indicating overall vegetation stability. NPP was negatively correlated with temperature and positively with precipitation and solar radiation, with precipitation having the most decisive influence. Climate change and human activities contributed 74.69% and 25.31% to NPP variation, respectively. These findings enhance our understanding of vegetation dynamics and support ecological protection and regional sustainability planning.