Study on the structural characteristics of plateau zokor tunnels based on ground-penetrating radar

Plateau zokor (Eospalax baileyi) is a small cave dwelling animal peculiar to the Qinghai-Tibet Plateau. Quantifying the structure of plateau zokor tunnels can provide a foundation for future studies on the effect of its disturbance on the ecological environment. Ground-penetrating radar (GPR) can acquire the structural characteristics of underground tunnels in a nonvisible, nondestructive, and highly efficient manner. In this study, the depth, diameter, and direction of plateau zokor tunnels were investigated using the GPR method, and compared with those obtained with the traditional digging method. The results showed that the tunnel position obtained by GPR was consistent with that obtained by excavation, and there was no significant difference between these two methods in tunnel diameter and depth (P > 0.05), indicating that the GPR method was able to obtain accurate results. The depths of plateau zokor tunnels ranged from 1.6 cm to 19.8 cm, with an average value of 11.9 cm; the diameters of the tunnels ranged from 2.1 cm to 14.4 cm, with an average value of 9.1 cm; the underground tunnels fluctuated slightly, but was generally distributed in the same horizontal plane. Moreover, there was a good correspondence between the location of the underground tunnels and the distribution of land surface mounds; the tunnels under the new mounds were more continuous and the tunnels under the old mounds were more fragmented. In general, the structural characteristics of plateau zokor tunnels were successfully obtained by GPR, and we were able to study the mechanism of its influence on soil properties and vegetation characteristics, and to further comprehensively assess the role of plateau zokor in the entire ecosystem.