110 / 2023-05-31 09:09:53

Impacts of open-pit coal mining and livestock grazing on plant diversity in a steppe: from the perspective of remote sensing

coal mining,grazing,plant diversity,spatial pattern,remote sensing

Both coal mining and grazing cause land degradation. Plant diversity loss is one of the characteristics. Labor-intensive ground surveys cannot analyze the effects of coal mining and grazing on plant diversity in large areas, and remote sensing offers a novel solution. However, previous studies mainly focused on plant α-diversity, largely neglecting β- and γ-diversity. Because existing remote sensing methods cannot obtain plant α-, β- and γ-diversity simultaneously. Therefore, it is not clear how coal mining and grazing affect the spatial pattern of plant diversity. In this study, we define the spatial pattern of plant diversity including the composition of plant diversity (α-, β- and γ- diversity) and the spatial distribution of plant α-diversity in a region of interest. The aims of this study were as follows: (1) to analyze the impacts of coal mining and grazing on plant diversity composition by considering α-, β-, and γ- diversity comprehensively; (2) to determine the impacts of coal mining and grazing on the spatial distribution of plant α-diversity; (3) to identify priority areas for ecological restoration from the perspective of plant diversity. Based on the analysis of variance (ANOVA), we applied a novel remote sensing method to obtain plant α-, β-, and γ-diversity maps. What's more, the α-diversity + β-diversity = γ-diversity. Then we performed spatial analysis. The results were as follows: (1) coal mining reduced the proportion of α-diversity in the total diversity (γ-diversity) but increased that of β-diversity. Grazing increased the proportion of α-diversity but decreased that of β-diversity. Coal mining increased the heterogeneity among plant communities, whereas grazing increased the homogeneity. (2) both coal mining and grazing reduced α-diversity. With increasing distance from the mine, α-diversity increased logarithmically. Coal mining affects plant diversity patterns by changing soil properties. Whereas, the soil properties did not change significantly before and after grazing. The impact of grazing on plant diversity is mainly due to animal foraging and trampling. (3) the severely affected range of coal mining on plant diversity is approximately 325 m. Simultaneous occurrence of coal mining and grazing can further decrease plant diversity. Therefore, when there is grazing around the coal mine, the severely affected range is approximately 400 m. The severely affected area is the priority area for ecological restoration and should be put into more efforts. Improving the soil quality can be an effective measure. These conclusions have practical guiding significance for government decision-making and can provide reference for other similar regions.