Ecological Indicators (Sep 2024)
Spatiotemporal variations in the impacts of small-to medium-scale mines agglomeration scale on landscape pattern and ecological risk in the watershed in a semi-arid ecologically fragile area
Abstract
Mining is one of the most pervasive of the various anthropogenic disturbances to landscape ecology. Currently, more attention is paid to the landscape ecological impacts caused by large-scale opencast mining, while small- to medium-scale mines (SMMs) are often neglected due to their small individual size. However, for SMMs, which account for up to 80 % of total mines in China, the impacts of their different agglomeration scales on regional landscapes, especially in ecologically fragile regions, are not yet clear. Therefore, a typical watershed with SMMs aggregated in the semi-arid ecologically fragile area of northwestern Liaoning Province was selected to explore the spatiotemporal dynamics of landscape patterns and landscape ecological risk (LER) under the influence of long-time mining by SMMs. Based on the geographically weighted regression model, the differences in the impact of SMMs on LER at different agglomeration scales were identified. The results revealed that (1) from 1989 to 2022, cropland as the dominant landscape decreased by 1504.82 hm2, while the area of mining land increased the largest, by 668.51 hm2. (2) SMMs were an important factor affecting the landscape pattern, and their multi-point dispersed mining destroyed the original large and intact landscape patches (e.g., cropland), leading to an increase in landscape fragmentation and heterogeneity, and a decrease in connectivity. (3) From 1989 to 2022, the total proportion of very high-risk and high-risk areas increased from 8.18 % to 38.29 %, which are primarily concentrated in the northeast of SHCRB where SMMs were aggregated. (4) The impact on LER was negligible when SMMs did not form an agglomeration scale, while the impact had a diffusion effect when SMMs formed a certain or larger agglomeration scale (the total number of mines was more than 100 and the total area was more than 500 hm2 in a kernel density region with a bandwidth of 1 km), i.e., the overall impact of aggregated SMMs on LER was much greater than the sum of the individual impacts of these mines. Additionally, LER was positively correlated with mine kernel density. The findings can provide a reference for ecological protection and systematic restoration of many similar watersheds with SMMs aggregated, as well as for SMMs around the world in future mining and planning.
