Multi-scale Landscape Spatial Relationship And Changes Of Landscape Pattern And Ecological Effect

The study of multi-scale landscape spatial relationship and landscape spatio-temporal changes which are key contents of landscape ecological planning is significant to finding out the mechanism and laws of landscape succession and searching the relationship between hunman being activities and ecological environments. Landscape multi-scale spatial relationship and changes of landscape pattern and ecological effect were studied in the scale of Yangtze River Basin and Wuhan city using 3S technology. The landscape structure and its spatial autocorrelation characteristic in Yangtze River Basin were studied using GIS technique firststly. Landscape classification mapping was researched using the method of knowledge decision tree with a case study of Landsat TM images in Wuhan city. On the basis, the changes of landscape metrics and landscape structure transfer were studied in Wuhan city from 1987 to 2007. Then the characteristics and changes of landscape pattern in Wuhan were studied using Ripley's K function, an important method of point pattern analysis. And the characterictics and changes of landscape structural segregation of different landscape types was studied using lacunarity analysis method in the process of rapid urbanization of Wuhan city. Lastly spatio-temporal coupling between landscape structure and ecological supporting capacity were studied using the theory of ecosystem services value and spatial accessibility. Accordingly means of improving ecological supporting capacity were put forward. Major conclusions of the study were as following.(1) The results showed that forestland, grassland and cropland were the dominating landscape types which accounted for more than 90 percent of the Yangtze River Basin's total area, while the area of water, urban & rural built-up land and other unused land were extremely small. Different provinces and municipalities in Yangtze River Basin shared sharply different landscape structures characteristic which could be divided into four zones in connection with a certain landscape spatial pattern. The provinces and municipalities with similar occupancy rate concerning all kinds of land use types globally clustered and adjoined in the basin, spatially auto-correlating significantly. But distribution centroid, pattern, spatial autocorrelation structure and regression characteristic were different about different land use types. Local spatial autocorrelation for spatial distribution about all land use types in the basin resulted from H-H clustering or L-L clustering, whereas spatial outlier was negligible. As a whole, the research demonstrated that the spatial distribution of all landscape types were distinctly of attributes of spatial clustering and regionality in the basin.(2) The results of Wuhan TM landscape classification mapping from remote sensing images showed that landscape classification method based on expert knowledge for remote sensing images can avoid the errors that created by the phenomenon of the same objects with different spectrum to some extent, and it could achieve high classification accuracy as an efficient and feasible landscape classification method for remote sensing images. Variables and their threshold value were keys to the classification method based on expert knowledge in the operation.(3) The results of landscape metrics and theie changes study in the middle scale of Wuhan city showed that the area of water, cropland and grassland decreased greatly from 1987 to 2007, shrinking 11.74%,12.27% and 57.75% respectively in the rapid urbanization process of Wuhan city. On the contrary, forestland and urban & rural built-up increased largely, jumping 146.45% and 187.31% respectively. Transfer matrix showed that decreased water was converted to cropland mostly, and cropland and grassland were major origin of additional forestland. In the meantime, landuse use comprehensive dynamics accelerated and land use intensity climbed distinctly. Meantime, all types of patches share a more dispersed distribution and irregular shapes and the whole landscape takes on a more fragmented pattern. Meanwhile, the whole landscape becomes more diversified and even due to similarity of area of different kinds of patches and flourishing land uses.(4) The study of landscape pattern characteristics in Wuhan using Ripley's K function demonstrated that farmland made up of landscape matrix while water, forestland, grassland, urban & rural built-up land and so forth were patches or corridors, which spatially clumped significantly in all scales under current study. Landscape aggregation of water was inferior to forestland, grassland, urban & rural built-up land. Landscape matrix, farmland, clumped spatially in fine scales but became random or uniform in coarse scales. Meantime, the area of forestland and urban & rural built-up land increased largely while water, grassland and farmland decreased greatly from 1987 to 2007. In addition, the landscape spatial characteristics of all landscape types changed a lot variously. On the whole, landscape aggregation of forestland and urban & rural built-up land decreased and became more uniform. Meanwhile water, grassland and farmland took on a more uneven and clumped landscape pattern.(5) The results of landscape structural segregation study using lacunarity analysis method showed that landscape segregation decreased successively from grassland, urban & rural built-up land, forestland, water and farmland. Landscape matrix, farmland, distributed randomly or uniformly in the whole landscape, sharing minor landscape segregation. Water shared similar landscape spatial pattern characterictic and greater landscape segregation in connection with farmland. Landscape segregation of grassland, urban & rural built-up land and forestland was marked, significantly clumped spatially in the city landscape. Landscape segregation of urban & rural built-up land and forestland decreased gradually from 1987 to 2007. Landscape segregation of grassland decreased from 1987 to 1996 and increased greatly from 1996 to 2007. Landscape segregation of water remained the same from 1987 to 1996 and increased from 1996 to 2007. The results of lacunarity analysis for landscape matrix farmland changed little, so its landscape segregation changed little.(6) The results of changes of ecological effect resulted from landscape pattern changes demonstrated that that ecosystem services couldn't ecologically sustain and support the rapid urbanization process of Wuhan city from the two aspects of whole amount of ecosystem service value and spatial accessibility respectively. Ecological supporting capacity declined sharply in the city, and ecological infrastructure conditions of the city degenerated distinctly in the past two decades. Spatially, ecological infrastructure conditions of the city's heart region degraded and regions shared fine ecological background conditions moved to outer suburbs centrifugally. Accordingly more necessary measures, such as landscape ecological planning of urban forest resources and ecological tourism planning of urban wetland resources, should be taken to enhance the provisioning of ecosystem services to our society and maintain the city's healthy and rapid development.