Comparison of rural residential renovation based on Lewis turning point and ecological connectivity

Abstract: There are more than 60% people living in rural area even though the urbanization of China is over 50%. That means many people move between rural and urban area, which are called peasant-worker. And this semi-urbanization phenomenon leads to rural people can not migrate to urban completely, and the rural residential area expands inevitably. Also because of the population growth and the resource consumption, it also puts pressure on the rural ecosystem. Rural residential renovation needs to preserve adequate rural population and at the same time to consider the influence for ecological patterns. Rugao county is one of the highest rural residence per unit area, and one of fastest urbanization areas in Jiangsu province. In recent years, the government takes Rugao as the rural reform pilot area, and put many rural residential renovation projects in this area aiming to solve the rural residence expansion and ecological problems. This paper took Million Hectares of Fertile Farmland Project of Chaiwan town, Rugao county as a case study. The main processing software included ArcGIS9.3 and Matlab, and GIS spatial analysis method was used for ecological resilience analysis. We used natural villages as an independent unit and ran the best ecological renovated model based on the Lewis turning point and ecological connectivity by minimal cumulative resistance model. The findings showed that rural population could not migrate to urban completely and urbanization had a certain limit based on the consideration of the necessity of agriculture production and the influence of other income sources. It showed that rural residence should be maintained at a reasonable scale, rural population flow and rural residential renovation should be taken as reasonable goals in the urbanization. As an intelligent algorithm, the genetic algorithm in the model had capability in intelligent decision support. It can take results quickly through the crossover, heredity and variation operator. The results of studied area showed that there were at least 53 results by genetic algorithm. The schemes can be applied in study area that was not unique. The urbanization can be achieved between 77.96%-78.63%, which preserved 21.37%-22.04% population in rural area for agriculture production, and this was consistent with international experience. Different patterns of rural residential renovation schemes can have different ecological influence, and different sizes of isolated ecological islands, and the island sizes can be different more than 2.29 times despite the similar urbanization rate. The paper suggested to take the lower influencing scheme under the suitable urbanization, and to take certain policy recommendations in order to implement rural residential renovation smoothly.