Spatial Patterns of and Temporal Variations in Carbon Storage in the Forest and Grassland Ecosystem of China’s Nature Reserves

Carbon storage is a critical factor for ensuring the provision of ecosystem services such as biodiversity conservation, particularly in nature reserves. Understanding the spatial and temporal dynamics of carbon storage within China’s nature reserves (NRs) is essential for evaluating their role in ecosystem conservation. Using NDVI values, we assessed vegetation carbon storage in NRs across China from 2000 to 2015. The results revealed a 63.06% increase in carbon storage within NRs over the 15-year period, with forest vegetation and grassland vegetation carbon storage increasing by 60.05% and 86.33%, respectively. Approximately 90% of NRs exhibited positive growth rates, with higher increases observed in northeastern and western China compared to other regions. While the carbon density of forest vegetation in NRs exceeded that of areas outside reserves, grassland vegetation displayed the opposite trend. Overall, vegetation carbon storage in NRs demonstrated a significant upward trajectory over the study period. These findings highlight the importance of nature reserves in safeguarding forest carbon functions; however, their protective effect on grassland vegetation carbon function was less pronounced.