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Background: In this study, we proposed that the population dynamics of non-native red-eared sliders (Trachemys scripta elegans) depends on the species' habitat extension and survivorship. We used a logistic equation with time-dependent habitat carrying capacity. In detail, the present carrying capacity depends on the red-eared slider population of the previous year. Anthropogenic activities such as the abandonment of previously captive red-eared sliders or the release due to religion customs would supply new habitats to the species. Therefore we assumed that anthropogenic spread increases the habitat carrying capacity. Based on the urbanization increase rate of 3% in Korea from 1980 to 2000, we assumed an annual spread of 3% to simulate the population dynamics of the red-eared slider. In addition, the effect on the population of an increase of natural habitats due to migration was simulated. Results:The close relationship between the distributions of non-native red-eared sliders and of urbanized areas demonstrates that urbanization plays an important role in providing new habitats for released individuals. Depending on the survivorship, the population of the red-eared slider in Korea increased 1.826 to 3.577 times between 1980 and 2000. To control population growth, it is necessary to reduce carrying capacity by reducing habitat expansion through prohibition of release into the wild ecosystem and careful managements of the wetland or artificial ponds. Changes in the habitat carrying capacity showed that the population fluctuated every other year. However, after several years, it converged to a consistent value which depended on the survivorship. Further, our results showed that if red-eared sliders expand their habitat by natural migration, their population can increase to a greater number than when they have a 99% survivorship in a fixed habitat. Conclusions: Further introductions of red-eared sliders into wetlands or artificial ponds should be prohibited and managed to prevent future spread of the species. Moreover, it is important to reduce the species' survivorship by restoring disturbed ecosystems and maintaining healthy ecosystems.

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The bloom of Aurelia aurita has been a serious problem for the marine ecosystem. Asexual 8 benthic polyp reproduction plays a major role in the jellyfish bloom. The intrinsic population dynamics of 9 polyps depend on the budding rate. Although a number of factors influence their budding rate, including the 10 presence of predators, prey, and competitors; the temperature, salinity, of the environment; and characteristics of 11 the settling substratum, this study uses only the temperature of the environment to examine the asexual 12 reproduction of the Aurelia aurita polyp. The experimental data are used from [8,9], where the most and only 13 matter of factor was temperature in the population growth of polyps of Aurelia aurita. The study uses the 14 Fibonacci sequence as a simple dynamic model of asexual reproduction and proposes population growth 15 function a(n) in which the intrinsic population growth rate of polyps is expressed as a function of time and 16 temperature. The results obtained using the temperature data from Ansan, west sea of Korea, indicate that it is 17 possible to predict the blooms of Aurelia aurita polyps , which may have considerable influence on the bloom of 18 medusa by using the mean sea water temperature. The population growth rate of the asexual reproduction is 19 very sensitive to the distribution of the seawater temperature. 20 21