The Evaluation and Key-Factor Identification of the Influence of Tourism on the Soil of Mount Tai

Abstract

Tourism has been proven to disturb the soil environments and stimulate heavy metal accumulation in scenic areas. Currently, research on the driving mechanisms of the impact of tourism on soil quality degradation is limited. Therefore, the aim of this study was to introduce a complex network method to comprehensively depict the impact of tourism on soil quality. To explore the key influencing factors, we collected 10 topsoil samples and 10 corresponding control samples from representative scenic areas in Mount Tai. Soil physicochemical properties (organic matter (OM), alkali dispelled nitrogen (AN), total nitrogen (TN), available phosphorus (AP), available potassium (AK), electrical conductivity (EC)), heavy metal (Cr, Cd, Pb, Hg, As, Cu) content, and microbial community diversity (by Eco-plate method) were analyzed. Additionally, complex networks of soil quality variables were established based on Pearson correlation coefficients. The results show that the OM, AN, and AP contents of scenic areas are 1.2, 1.03 and 1.18 times higher, while the AK content is 0.97 times lower, than those of the control sites, respectively (mean values of samples from scenic area vs. contorl sites). The single factor index of Hg, As, Pb, Cd, Cu, and Cr are increased from 3.65, 0.53, 0.85, 1.25, 0.78 and 0.58 to 3.69, 0.57, 1.24, 1.75, 0.97, 0.63 and 3.19, respectively, which means that tourism significantly exacerbates soil heavy metal accumulation. Additionally, the soil microbial activity and diversity are slightly reduced due to tourism. In general, the difference in the mean value of each soil quality variable between the scenic spot and the control site is not significant. However, tourism significantly reduced the connectivity and integrity of soil quality variables, which ultimately destabilized the soil, inferred from the comparison of the network’s topological parameters. Therefore, raising the content of soil OM and AN and controlling Cd pollution should be given more priority in soil ecosystem protection to counteract the negative impact of tourism on Mount Tai. It was the major limitation of the study that few typical scenic spots were selected as sampling points on Mount Tai. However, this study is sufficient to show that the complex network approach can be extended to other similar studies of soil quality degradation driving mechanisms.