Abstract:

Based on multi−source data using the improved CASA model and soil heterotrophic respiration model, the net ecosystem productivity (NEP) of Shanghai in 2000−2016 was calculated to characterize the carbon sink status of vegetation, and the spatial and temporal dynamic evolution characteristics of vegetation carbon source/sink and their influencing factors were investigated using the trend analysis, stability analysis, and partial correlation analysis. The results showed that (1) the annual mean value of NEP for vegetation in the Shanghai region from 2000 to 2016 was 96.73gC·m⁻²·y⁻¹, with a decreasing trend in temporal variation of 1.87gC·m⁻²·y⁻¹ (P<0.05). (2) The area of the vegetation carbon source area in Shanghai accounted for 24.20%, and the area of the carbon sink area accounted for 75.80%, and the vegetation space as a whole showed a carbon sink situation. (3) The average slope of the vegetation NEP trend was −3.63, and the coefficient of variation was 76.41% of the area of medium and high stability level, with a high overall stability. (4) Vegetation NEP showed a weak negative correlation with temperature, a significant negative correlation with soil heterotrophic respiration with a partial correlation coefficient of −0.48, and a significant positive correlation with precipitation and solar radiation with partial correlation coefficients of 0.57 and 0.43, respectively.

Key words: Vegetation carbon source/sink, Net ecosystem productivity, Net primary productivity, Coastal city