Impact of reclamation-driven land use change on vegetation carbon store in mining areas

Mining activities and climate change severely impact eco-environment of the mining areas. However, land reclamation effectively reclaimed the mining area and restored the environment. It is important for ecological benefit evaluation in restoration of mining area to analyze the effect of climate change and human factors on ecological environment of mining areas. The researches concerning carbon storage of soil and vegetation in the mining area have gained a lot of results and provide us an effective tool for further evaluating the effect of climate and human activity on environment in the areas. In this study, we estimated vegetation carbon storage using a modified CASA (Carnegie Ames Stanford Approach, CASA) model in Ji’ning where the environment had been highly disturbed by mining and reclamation activities. Then Chikug’ model was used to evaluate the effects of both climate change on carbon storage of the mining area. The results suggested that: 1) with year 2003 as a key point, the carbon storage in the research area increased from 1987 to 2003, and then decreased till 2010, and increased again during 20102014. The carbon storage of the study area in 2003 was the highest point (4 645.738 t) during the study period, and in 2010 was the lowest point (3 687.741 t). 2) The net primary productivity (NPP) of vegetation in the mining area was changed by comprehensive effect of both climate and human activity. The range of disturbance of climate change on carbon density was 2.8329.465 gm^-2, the range of disturbance of mining activities on carbon density was 9.89713.435 gm^-2, and the range of disturbance of combined mining activities and land reclamation on carbon density was 11.13212.839 gm^-2. The amplitude of carbon density was 2.8329.465 gm2 influenced by climate change, 9.897 13.435 gm^-2 influenced by mining activities, and 11.13212.839 gm^-2 influenced by combined effect of coal mining and mining land restoration. Although the change of carbon density in the mining area was influenced by both climate change and anthropic factors, the influence of anthropic activity was stronger than climate change on the change of carbon density. 3) Coal mining destroyed cultivated lands and ecological environment, which led to a severe loss of carbon store. The carbon storage loss was 30.503 t in 19871995, 38.963 t in 19952003, and 189.709 t in 20032014. 4) Coal mining activity obviously increased the loss of vegetation carbon storage in this area, but land reclamation recovered the loss, and the maximum recovery was 4.731%. This, to a certain extent, alleviated the destruction of ecological environment due to coal mining activities. Therefore, land reclamation was a powerful strategy for alleviating ecological damage due to mining activities, and improving soil productivity.