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

Organic carbon (C) storage is a key factor in ensuring the provision of ecosystem services such as biodiversity conservation, especially in nature reserves. C storage and its changes in China’s Nature Reserves (NRs) are important to act on its role in ecosystem conservation. We based on NDVI values to assess the spatial and temporal variations of vegetation C storage in NRs from 2000 to 2015 in China. Results showed that the C storage in NRs increased by 63.06% within 15 years, of which the C storage of forest vegetation and grassland vegetation increased by 60.05% and 86.33% respectively. 90% of the NRs generally showed positive growth rate, and the growth rate of the northeast and west part NRs of China was higher than other regions. The carbon density of forest vegetation in nature reserves was higher than the region outside nature reserves, however, the grassland showed an opposite result. In general, the vegetation C storage in NRs showed an increasing trend in 15 years, and nature reserves played an important role in protecting forest carbon function, but the effect on protecting grassland vegetation carbon function was not obvious.