On Landscape-structure-based Regulation And Control On Land-use Ecological Risks In The Core Area Of Changsha-Zhuzhou-Xiangtan

It is an urgent task to explore a good way to efficiently regulate land-use ecological risk in rapid urbanization within the concern of regional landuse structure and function changes to achieve ecological, economic and social sustainable development. With the aid of the research methods and technologies in such fields as geography, landscape ecology, management, mathematics&computer science, the dissertation, selecting Changsha-Zhuzhou-Xiangtan (abbr. C-Z-T) core area as the case, analyses its20-odd-year scale characteristics in landuse changes and factors of driving forces on ecological risks from the perspective of landscape structure and function changes to mark the signs and hints of such risks as landuse structure changes and function deterioration caused by improper landuse, attempts to establish a landscape-ecology-based risk evaluation index system and model to make assessment of landuse ecological risks at different scales and finally, based on the assessment results, puts forward how to efficiently regulate landuse ecological risks from such aspects as regulation objectives, focuses, scale selection, decision-making and strategies.The major results are listed as follows.1. Scale analysis of characteristics land-use changeThe scale analysis of land-use change characteristics from a wavelet analysis on typical transect line of the belt along the Xiangjiang River as the typical land-use region on the basis of the data of land-use change extracted from the remote sensing image data in four periods from1989to2008shows ⅰ) that the different degrees of sensitivity of each quarter of the C-Z-T core area to scale change determine their selection in land-use characteristic scale, ⅱ) that the characteristics scale selection varies as the land-use and landscape structure in different parts change, ⅲ) different land-use and landscape patterns have different scale characteristics, and ⅳ) that the value of scale characteristics is inversely proportional to the landscape sensitivity, which is supported by the results ⅰ) the quarter around the city centre has the highest value but the weakest sensitivity to scale change, thus about3,300m parcel analysis being the most appropriate and ii) the urban fringe quarter has the lowest value but the strongest sensitivity to scale change, thus about1,980m parcel analysis being the most appropriate.2. Analysis of driving factors and mechanism of land-use ecological riskIts changes of land-use structure and function are the major reason for the area's land-use ecological risk. On the basis of the analysis of the driving factors of land-use change, the ecological characteristics of landscape structure and pattern change have been explored and an assessment has been made on the service value in ecosystem to better comprehend the factors' driving process. The research shows ⅰ) that the socio-economic factor is the dominant driving factor of land-use ecological risk in the area, ⅱ) that the area of construction land increases with the GDP, and ⅲ) that arable land and grassland have the strongest sensitivity, woodland and water the weaker, and construction land and idle land the weakest.3. LUER assessment and characteristics analysisOn the basis of the combination of the analysis of the area's land-use change and its ecological risk driving factors, an assessment indicator and its model have been established for the source-and-sink landscape. As the results show, land-use ecological risk in the built-up urban area is higher than other areas. The overall risk value of urban districts in Changsha, which has a largest distribution of higher risk areas and highest risk areas, ranks the highest, that in Xiangtan the second and that in Zhuzhou the last. The land-use ecological risk in the core area of Changsha-Zhuzhou-Xiangtan grows from the normal level to the medium level or even to the relatively high level. Low-risk areas scatter, which exerts much pressure on ecological risk regulation and control. The measurement of assessment units also influences the accuracy of assessment results. A2km×2km unit, compared with a10km×10km unit, is more suitable for land-use ecological risk assessment of urban agglomeration.4. land-use ecological risk regulation and controlOn the basis of the analysis of land-use ecological risk factors, the ecological risk assessment results and the rule of risk indicator change, the objectives and focuses of risk regulation and control are set to find the proper time, space and scale for function regulation and control of land-use ecological risk. With the characteristics of the main regulation and control system into consideration, Agent-Based Modeling (ABM) is adopted in micro-level action simulation and decision of land-use risk regulation and control and a variety of regulation and control means are proposed for multi-level land-use ecological risk.