Ecological risk assessment and spatial prevention tactic of land destruction in mining city

Abstract: Mining is a key economic activity, and it contributes greatly to the economic growth of China. However, the consequents of land destruction, such as ecological losses and environmental pollution, could adversely damage the living environment and sustainable development of the mining area. In recent years, research studies on ecological risk assessment have been hotspots in the field of land use and environmental science for mining cities. Land destruction is recognized as the most direct and obvious source of ecological risk in mining areas. A lot of theoretical frameworks and qualification models have been built to evaluate the ecological risk of land destruction. However, it is not clear how the spatial heterogeneity of ecological risk based on land destruction can be quantitatively visualized, and what kind of targeted prevention measures should be taken in various types and grades of ecological risk, which leads to some ineffectiveness of land reclamation plans in mining cities. In this paper, a framework for ecological risk assessment and spatial prevention of land destruction for the mining city was proposed. Liaoyuan city in Jilin province, as one of the representative mining areas in China, was chosen as the case area. First, the data of land use type, land destruction type and site were vectored into a GIS platform, and an integrated GIS-based model involving the ecological sensitivity evaluation, the cumulative effect evaluation of land destruction and the evaluation of the probability of exposure to destructed lands, were constructed and applied to quantify the comprehensive value of ecological risk based on land destruction. Secondly, the spatial pattern of ecological risk of land destruction was visualized and illustrated by four zones with degrees of comprehensive value: the high-risk zone (2.5% of the total area), the medium-risk zone (17.4 % of the total area), the low-risk zone (39.1% of the total area) and the risk-free zone (41% of the total area), in which the dominant risk factors were differentiated. Thirdly, the zoning matrix of land use for ecological risk prevention was built, based on risk zones, which can be used to picture the land use control zone. The zoning matrix of land use included specially-protected environmentally sensitive areas and ecological conservation areas, ecological restoration areas, ecological coordination areas, ecological reclamation areas, limited development areas, mining development areas, and urban development areas. The regionalization is consistent with the land use pattern from 2010 Urban Master Planning of Liaoyuan City, which shows this prevention-oriented land use zoning approach is effective and feasible. The study reveals that the quantitative evaluation can not only provide the spatial heterogeneity of ecological risk, but also provide an operational approach to integrate land reclamation into land use planning by making targeted risk prevention decisions. This study helps to improve the effectiveness of land reclamation and land management in the mining city.