Research Of Evaluation And Planning Of Urban Ecosystem Based On Complexity Theory

This dissertation first reviews the research progress on complexity theory and its applications to the models of urban ecosystem, and accounts for the current problems on complex ecosystem models. Then from the respective of the mathematic theories, methodologies and applications and based on complexity theory, the focus is given on the development of new theory and new methodology for the urban ecological modeling establishment. This dissertation systematically studies the urban ecosystem problems in such areas as follows: evaluation of ecological environmental quality, ecological functional regionalization, river ecosystem health evaluation, land-use suitability evaluation, river ecosystem restoration, and urban greenway planning. By means of complexity theory and ecology, we hope to found some ecosystem models which are more accorded with the objective rules and facts.The main work and novel results of this dissertation includes the following elements.(1) Under the condition of complex ecological environment and inexact cognition of parameters, by the methods of remote sensing (RS), geographic information system (GIS) and space simulation, an evaluation model of ecological environmental quality was proposed. By interpreting Landsat TM/ETM+ remote sensing image, Changsha City, a typical hilly region of red soil, has been taken as an example to the availability and reliability of the evaluation model. The results showed that only 7% of the total land areas (approximately 827.64 km2) are maintaining at higher or the highest grades of the ecological environmental quality in Changsha City. However, there are 52.4% of the lands (approximately 6187.14 km2) are getting worse or the worst grades of the ecological environmental quality. The results of the case study indicated that the evaluation model of ecological environmental quality offered an effective reference for analysis of ecological services importance and ecological functional regionization. (2) Based on the methods of remote sensing (RS), geographic information system (GIS) and space simulation, evaluation models for ecological sensitivity and ecological services importance were proposed. The indicators systems of ecological sensitivity and ecological services importance evaluation were established to analyze ecological functional regionization. Based on the results of ecological sensitivity grade, ecological services importance evaluation and Chapter 1, the map of ecological functional regionization in Changsha City was obtained. The results can be used as scientific references to carry out ecological restoration and planning strateges. (3) Based on analyzing uncertainties when determining indicators system of ecosystem health assessment, an indicators system and a model for the evaluation of urban river ecosystem health was proposed. The model could offer the feasible and reliable base of decision-making for the river environment management. (4) An integrated method for land suitability evaluation (LSE) based on geographic information systems (GIS) under uncertainty was proposed. The method of grey relational analysis (GRA) was incorporated into analytic hierarchy process (AHP) to address the uncertainty during the process of evaluation. The systematic evaluation approach has been tested by using Changsha City as a case study. The research outcome can be used as a basis for urban planners and researchers to deal with the development of cities and their surroundings in regions of highly ecological and environmental sensitivity. (5) On the basis of the theory of restoration ecology, the concept and principles of urban river ecosystem restoration were discussed. According to the research results of river health evaluation in Chapter 4, the milti-objective urban river restoration mode was proposed,which including three parts, vegetation restoration, biodiversity protection, and landscape design of river corridor. It was dementrated that the final purpose of urban river restoration should be maintaining the ecological integrity. The compound development mode of urban river corridor was also discussed, which including functional and spatial development mode. (6) Based on the discussion on the theory of restoration ecology and landscape ecology of urban green space system planning, according to the need of economic development and the results of the above research, the framework and measures of Changsha green space system planning was proposed.Based on the complexity characteristics of urban ecosystem, the systematical theory and ecology, assessment and planning of urban ecosystem were developed furtherly. This study has been helpful to develop ecosystem modeling based on complexity theory and further improve cognition to the development law of urban ecosystem. Moreover, the case study of Changsha City proved that the models based on complexity theory could more accurately and effectively account for the complex behaviors of urban ecosystem. The study could offer theoretical and technical bases for urban ecological planning and promote the sustainable development of urban ecosystem more effectively.