Effect of ecological engineering design on biological motility and habitat environment of Hynobius arisanensis at high altitude areas in Taiwan

Abstract

Because of thriving tourism in recent years, concrete constructions have been installed by creeks in order to protect the safety of tourists, but the effect of concrete structures on the habitats and the mobility of certain species is still unknown. This study evaluates the different effects of various water bank substrates in terms of the influence on Hynobius arisanensis's (Maki) motility in Alishan National Park. Comparing the concrete area with two other areas where primitive streams flow by, it was observed that concrete structures lead to increased flow velocities, shallower water depths and poorer water quality. In the biological motility assessment, moss, rock, wood, clay and concrete as distinct water bank substrates were used to test the climbing ability of H. arisanensis. Based on the seasonal humidity changes in winter and summer of Alishan area, H. arisanensis's climbing ability was tested in two conditions, high humidity/high temperature and high humidity/low temperature. It was determined that climbing ability dropped rapidly with increasing slope angles. It was observed that the climbing ability of H. arisanensis is slightly decreased in low temperature. Regarding the upper limit of design slope suitable for H. arisanensis are: wood and concrete are ≤45°, moss surface ≤60° and clay surface ≤30°. The results here can provide insights for future engineering projects on creek banks to benefit H. arisanensis conservation.