Abstract: Understanding the mechanisms driving changes in vegetation carbon sequestration is a scientific support for achieving regional “dual carbon” goals and high-quality development. However, current research lacks comprehensive consideration of the spatiotemporal autocorrelation of influencing factors, and fails to accurately reflect the dynamic impact process of these factors. We identified the spatiotemporal variation characteristics of vegetation carbon sequestration in northern Guangdong using meteorological data from 31 national meteorological stations and vegetation net primary productivity (NPP) data within a 10 km radius from 2001 to 2020. By constructing a spatial lag model of panel data and combining partial correlation analysis and dominance analysis methods, we analyzed the role of climate factors, and investigated the spatial variations of the influencing factors by the geographical weighted regression model. We further quantified the contribution of climate factors and human activity factors to vegetation carbon sequestration changes with the residual trend method. Results showed that, from 2001 to 2020, the average carbon sequestration in the study area was 955.43 g C·m^-2. Vegetation carbon sequestration in this region showed a fluctuating downward trend, with strong spatial heterogeneity. The annual average relative humidity, annual average sunshine hours and annual average precipitation were climate factors with significant impacts on regional carbon sequestration changes. The spatial differences of those influencing factors were considerable, and there was a strong correlation with altitude. Compared to climate factors, human activities were the main influencing factor of vegetation carbon sequestration variations in northern Guangdong, with an average contribution rate of 70.2% for human factors and 29.8% for climate factors.

Key words: net primary productivity, vegetation carbon sequestration, spatial lag model, climate impact mechanism, contribution