Research On The Optimizing Distribution Of Rural Settlements For Ecological Security

Ecological security is the status of regional development, which is not restricted or threatened by the ecological environment. With the development of economy and the improvement of urbanization, people are in urgent need of the improvement of the ecological environment. The irrational layout of land leads to more and more conspicuous conflicts between human and land. For a long time, the rural settlements in China are extensive use, small size, layout confused, lacking unified planning. This condition did harm to the ecological environment improvement. The rational remove of rural settlements can reduce the scale, increase the intensive degree, improve the ecological environment, and increase the cultivated land area. How to arrange the present rural settlements rationally is a key problem for rural land use work. Therefore, it’s necessary to study the optimizing methods and procedures of rural settlement, to achieve rural settlement layout optimization, and to provide theoretical reference for land use planning and construction of town-village system.Taking Jiaze Town Wujin District Changzhou City as the study area, with the support of GIS spatial analysis technology and gravity model, this study analyzed the present condition and evaluated the suitability of rural settlements for environment security, then classified the rural settlements and determined the growth core. This study reclassified the rural settlements and determined the final layout optimization. Here are the main contents and results of this study.(1) Present condition analysis of rural settlement. With the support of GIS spatial analysis technology, this study analyzed spatial relationship between rural settlement scale and different distances to ecological land, roads and public facilities. The patch scale is small and the patch density is great in Jiaze town. The landscape pattern index and CV was carried out to analyze the rural settlement shape features and discrete characteristics. There is a big difference about regular patches among administrative villages. And the patches are aggregated in the whole town. The study analyzes the spatio-temporal variation and hotspot on rural settlements. The rural settlement scale was increased a lot from 2007 to 2010, and decreased a little from 2010 to 2013. This study monitored the local statistics significance by using the Getic-Ord Gi* statistics. After 2010, the cold spot was divided into two parts, and the scale was smaller than before. The poor layout of the present rural settlement threatened the ecological security.(2) The rural settlement suitability evaluation. This study calculated the rural settlement suitability by choosing 15 factors to construct evaluation system and determining weight in AHP. In this paper, we used the natural break method to divide the rural settlements into four types based on the suitability score. They were optimal suitable development patches, general suitable development patches, poor suitable reserved patches and unsuitable patches. Overall, the suitability score is high in Jiaze town. The low score area was coincidence with the high kernel density area. And 22 rural residential patches were chosen as the growth core from the premium suitability patches according to certain standards and principles. We eliminate the growth core patches and the unsuitable patches from the whole patches, and then we regarded the rest of the patches as the non-growth core patches.(3) Carry out the rural settlement layout optimization. The relocation and combination patches were chosen based on the relative relationship between the rural residential patches and its adjacent land type from the non-growth core patches. The maximum range of each core patch was determined by weighted voronoi map. This study demarcated 21 growth control ranges by using the strongest gravity line, and determined the max scale of growth core due to the ecological and planned exclusion layers. According to the methods and procedure above, the rural residential patches were reclassified to four types:urbanization-based area, priority developing area, reserve-control area and relocation and combination area. The determined max scale of the growth core was smaller than the relocation and combination patches area. The reserve-control type patches have the largest scale contrast with other types. Based on the rural settlement suitability evaluation results, this paper proposed a new approach to develop the layout optimization of rural settlement by using the weighted Voronoi map, the gravity model and the relationship between the rural residential patches and its adjacent land type. And it is the innovation in this paper.