| Dengkou county is located in the arid and semi arid area where Ulanbuh Desert and Hetao Plain Interlaces. The county economy has achieved a great degree of development due to the implementation of policies such as the development of the West. However, the ecological environment problems including the expansion of the desert, the fragmentation of the ecological land and the block of the landscape ecological flow have been intensified.The association and feedback between structure and function, pattern and process is the basic proposition of landscape ecology (Turner,1989; Zhang H Y.2000). The evolution trend from 2000 to 2014 and optimization scheme of landscape pattern of Dengkou was studied using GIS and RS technologies under the guidance of the theory of landscape ecology in this research. This research includes the following contents(1) The distribution and evolution characteristics of landscape types in Dengkou county was studied quantitatively using landscape pattern transfer network, landscape pattern dynamics, landscape center of gravity migration analysis, landscape transfer density analysis, landscape pattern index and other methods. The result shows that:Transfer trend from desert landscape to water landscape and forest landscape during these years was very obvious; The construction landscape expanded rapidly; The degree of fragmentation of ecological landscape is relatively high; The landscape connectivity is low and lacks dominant landscape, the landscape pattern still needs to be optimized.(2) The suitability in slope, bury of groundwater, aridity index, the distance from roads of each landscape types was comprehensively evaluated using the idea of the niche suitability model, and a suitability of atlas was generated according to the result. The relationship between landscape pattern index and non-transition probability was analysed. Based on the relationship that was found in the research, a non-transition probability map of Dengkou county was generated. Using the suitability of atlas and the non-transition probability map as the evolution rules, a C A/Markov model was performed to simulate the optimal allocation of landscape types in the county, and a landscape pattern optimization plan was proposed.(3) Based on the optimal spatial allocation pattern of landscape pattern of Dengkou, the cumulative cost resistance surface against landscape ecological flows was constructed under the guidance of minimum cumulative cost distance model. The potential ecological corridors were extracted via minimum cumulative cost path analysis. The maximum threshold value of the cumulative resistance surface was analyzed, and the potential ecological nodes in the county were extracted by the overlay analysis with the ecological corridor. Based on the analysis of ecological corridor density and the classification of ecological nodes, the importance of different ecological corridors and ecological nodes was determined. And a point, line, surface interleaving ecological network was constructed.The main features and innovations of this paper can be summarized as follows:A thorough analysis of the landscape pattern evolution of the study area was performed and the ecological corridor and ecological node was screened according to the landscape transform density; Referencing the idea of the niche suitability, the transform regulation was constructed, and the CA/Markov model was used to construct the landscape pattern optimization plan. And the influence of subjective factors was effectively avoided due to the models used. Based on the result of the identifying of the key components of landscape pattern, the importance level of ecological corridors and ecological nodes in practical ecological planning and construction was determined. The research has certain guiding significance to the practical ecological construction work. |
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