원문정보
초록
영어
The development of transportation causing easier migration of species globally, and consequently those exotic species could cause serious ecological problems to local ecosystem. Hence, developing proper remove tactics should be one of the important topic in invasive species management. American bullfrog (Lithobates catesbeianus), is one of the most successfully introduced species in the world, which can survive in a variety of environments and climates. Invasive bullfrogs directly or indirectly influenced native ecosystems through competition, behavior modification, habitat control, disease, and parasite infestation. Removing activity is not easy because of its unique adaptability and dispersion ability. In this study, we test traps with different attractants according to bullfrogs’ behavior and ecological characteristics. We set 12 survey sites in each of 2 locations, Gunsan and Seosan and recorded the number of individuals of adults and juveniles, presence of tadpoles, calling index, and environmental factors (air temperature, humidity, air pressure, water temperature, pH, conductivity, wind speed) in each sites. We also set six treatments, combining adult attractants (control, light, calling) and tadpole (control, bait). In all sites before setting traps, we found 2.29 ± 2.56 (mean ± sd) adults with 0.71 ± 0.91 of calling index. Traps captured an average of 0.67 ± 1.55 (0-7) adults and 4.21 ± 15.73 (0-75) tadpoles in a single site. Simple regression showed that the number of observed adults and CI have positive correlation with the number of captured adults (r1=0.54, r2=0.41, p<0.05), but the number of adults wasn’t in relation to any environmental variables. Two-way ANOVA showed no difference in adult capture rate depending on the type of treatments and the observation power was very low. The number of captured tadpoles in each site was 8.42 ± 21.89, which did not differ among treatments, but only traps with food bait captured tadpoles successfully, indicating tadpoles may be attracted by food resource. In future studies, additional experiments will be conducted to increase statistical confidence and compare the efficiency of each treatment group in order to improve effective management strategies and policies for exotic species.
