Climatic effects and impacts of lakeshore bank designs on the activity of Chirixalus idiootocus in Yilan, Taiwan

Ecological engineering is the design of sustainable systems, consistent with ecological principles, which integrate human society with its natural environment for the benefit of both. In 2001, the government of Taiwan began to use ecological engineering as a therapy to nurse the damaged environment and found it worthwhile for further promotion for Taiwan's ecological environment. In recent years, the threat to amphibian animals is becoming more and more serious. The problem that concrete is mostly applied as a construction material on lakeshores in Taiwan has resulted in the obvious decrease of the habitats on which amphibian animals rely; hence, the need to develop the relevant design specification considering protecting the amphibian is imperative. Chirixalus idiootocus, an endemic species in Taiwan, is a small brown tree frog widely distributed in altitude ranging under 1500 m [Chen, W.S., 2003. 31 Frogs in Taiwan. Wild Bird Society of Taipei, pp. 62-63 (in Chinese)] with its unique breeding habitat [Kuramoto, M., Wang, C.S., 1987. A new Rhacophorid Treefrog from Taiwan, with comparisons to Chirixalus eiffingeri (Anura, Rhacophoridae). Copeia 4, 931-942]. Since its uniqueness and importance, it has been a good indicator to reflect the environmental change. However, the understanding of this species is still too little and the methods to protect them have not been developed yet. The goal of this study was to understand the impacts of different substrates, gradients, and humidities of lakebank slopes on the activity of Chirixalus idiootocus. Experiments were carried out on the samplings collected in the field at Chang-Pi Lake. Among the experimental results obtained in this study, the ability of jump height and jump length were 12.93-14.03 cm and 38.15-39.19 cm, respectively. The male group (♂) showed the best adhesive ability on awn grass (5.11 × 10-2 N/g) at 45° slope, and the (♀) group performed the worst on sand (0.43 × 10-2 N/g) at 75° slope. Female frogs showed significant worse performance than male in jump height, jump length, and adhesive abilities, so were considered a target reference to design bank slopes based on their vulnerable behavioral capacity. With better comprehensive results obtained in this study, suggestions for the bank slope designs were thus proposed as a useful reference for ecological engineering promotion in Taiwan. © 2007 Elsevier B.V. All rights reserved.