Abstract: Terrestrial ecosystems in Heilongjiang Province have strong carbon sequestration capacity but vulnerable to climate change. Analyzing the spatio-temporal variations of carbon budget of terrestrial ecosystems in this region and the impacts of climate change is of great significance for improving ecosystem carbon sequestration in Heilongjiang Province. Based on 1961-2022 climate data and leaf area index data, we adopted the ecosystem carbon cycle BEPS model to quantitatively simulate the net primary productivity (NPP) and net ecosystem productivity (NEP) of terrestrial ecosystems in Heilongjiang Province, and assessed the climate impact. The results showed that the BEPS model could simulate carbon sequestration capacity of Heilongjiang Province. From 1961 to 2022, ecosystem carbon sequestration capacity in the study area increased. NPP increased by 1.5 g C·m^-2·a^-1 on average, and the increase trend was more significant after 2010 with an annual rate of 7.5 g C·m^-2. Forest carbon sequestration capacity was the strongest, and the increment of carbon sequestration capacity of farmland ecosystem was the most significant. In the context of climate warming, the minimum temperature, precipitation, and wind speed significantly affected carbon sequestration capacity, with precipitation being the most important factor. During the study period, the correlation coefficient between precipitation and carbon sequestration in Heilongjiang Province increased overall, and the relative contribution rate was the highest, accounting for 46.1%. The relative contribution rate of precipitation to vegetation NEP was 67.1%.

Key words: terrestrial ecosystem, BEPS model, net primary productivity, net ecosystem productivity, climate impact assessment