Ecologically based landscape pattern optimization in northwest of Beijing

Supported by the technologies of remote sensing(RS) and geographical informa-tion system(GIS),we chose northwest of Beijing as a study area and gave priority to under-standing of the spatial-temporal characteristics of landscape pattern change through visually interpreted Landsat TM images of 1989,1996 and 2005.It is believed that there were a series of landscape ecological problems caused by city expansion:landscape ecological connec-tivity was low;landscape structure was simplified;the fragmentation of green land patch was more obvious on the plain areas,moreover,spatial distribution of green land was unbalanced.For this reason,this study adopted accumulative cost distance model,combined with eco-system services and spatial interactions of landscape types,analyzed the spatial difference of the ecological function and the compactness of landscape structure in the study area,and further discussed the landscape pattern optimization proposal.We find that it is essential to protect and establish ecological sources,to establish urban ecological corridors,and to es-tablish ecological nodes at the landscape ecological strategic positions so as to intensify spatial relationships among landscape elements and maintain continuity of landscape eco-logical process and pattern in the course of city expansion.The methods and final results from this study are expected to be useful for landscape ecological planning in Beijing region.

Landscape Pattern Optimization of Chengdu Based on Modern Garden City

TOptimization of regional landscape pattern is significant for improving function and value of ecosystem,and restraining the expansion of urban layout.Taking Chengdu City for example,this paper applied RS and GIS techniques,landscape indexes and ecological service function evaluation to further analyze the temporal and spatial characteristics of landscape pattern and spatial differences of regional ecological functions,and on this basis,identified the spatial distribution of ecological source lands.Based on the long-term objective of building Chengdu into a modem garden city,this paper applied the accumulative cost distance model and introduced garden city theory to construct regional ecological corridors and ecological nodes,and explored the approaches of optimizing landscape pattern of modem garden city.The results showed that a great deal of arable land has been transferred to construction land in the urbanization;intensity of regional ecological functions showed obvious spatial differences;ecological source lands were mainly distributed in the Longmen Mountain,the Qionglai Mountain,the Changqiu Mountain and the Longquan Mountain;according to actual conditions of the study area,the road ecological corridors,river corridors and agricultural corridors in the layout of "four rings and six radial corridors" were constructed;ecological nodes dominated by intersection,wetland and forest park were formed.This research method and results are significant references for building Chengdu into a modem garden

Identification of the ＂source＂ and ＂sink＂ patterns influencing non-point source pollution in the Three Gorges Reservoir Area

Non-point source pollution is one of the primarily ecological issues affecting the Three Gorges Reservoir Area. In this paper, landscape resistance and motivation coefficient, which integrated various landscape elements, such as land use, soil, hydrology, topography, and vegetation, was established based on the effects of large-scale resistance and motivation on the formation of non-point source pollution. In addition, cost models of the landscape re- sistance and motivation coefficients were constructed based on the distances from the land- scape units to the sub-basin outlets in order to identify the ＂source＂ and ＂sink＂ patterns af- fecting the formation of non-point source pollution. The results indicated that the changes in the landscape resistance and motivation coefficients of the 16 sub-basins exhibited inverse relationships to their spatial distributions. The landscape resistance and motivation cost curves were more volatile than the landscape resistance and motivation coefficient curves. The landscape resistance and motivation cost trends of the 16 sub-basins became increas- ingly apparent along the flow of the Yangtze River. The landscape resistance and motivation cost models proposed in this paper could be used to identify large-scale non-point source pollution ＂source＂ and ＂sink＂ patterns. Moreover, the proposed model could be used to de- scribe the large-scale spatial characteristics of non-point source pollution formation based on ＂source＂ and ＂sink＂ landscape pattern indices, spatial localization, and landscape resistance and motivation coefficients.