| The dramatic changes of landscape patterns will influence the structure and function of ecosystem and the terrain is the main natural limiting factor that impacts the formation and changes of landscape pattern. The researchs about land resource allocation most focus on the maximization of economic benefit and the dealing with land quantities, which ignore the influence of spatial pattern factors to ecology. However, the formation and development of landscape patterns are reflected by spatial and quantity structure under the double impaction of nature and society.This article chooses Huailai County as the study area, which is the typical area of northwestern Hebei mountain-basin area, and analyzes the change features of landscape and its patterns during 1993-2013 using the indexes of land use dynamic index, information atlas and landscape indexes on the basis of the relationship of terrain and land use, then discusses the driving factors of landscape viaration with logistic regression model; discussing the relationship between terrain and landscape patterns and dividing gradient zones of landscape dominant type; building ecological source, ecological corridor and ecological node by MCR model and evaluating the importance of ecological nodes, then dividing the optimization layout partition of landscape. The conclusions are:(1) The fragmentation of landscape pattern in Huailai County increases during 1993-2013, while connectivity and stability decreases. The patch density and fragmentation degree of six land types turns to increase, while the average patch area reduces. The patch area of construction land keep expanding, which leads to the areas of vulnerable landscape types, for example cultivated land, reduce. And then the heterogeneity and fragmentation of whole landscape increase, the connectivity keep reducing, which limits the ecological flow. The result of driving factors analysis show that economic development is the main factor that leads to land use changes and terrain is the primary factor that limiting the change directions of land use. The average land net income and population density have a major impact on the distribution of six land types and the socio-economic factors are the most important factors that influence the distribution of land types.(2) The changes of landscape patterns appear terrain gradient under the action of terrain factors. In the areas with lower degree of elevation, slope and topography degree, the construction land, mining land, cultivated land, garden plot and water, which are close related to human life, are wide distribution, and the dominant position of the five land types locates in the lower terrain class areas. While forest, grass land and other land types mainly locate in higher terrain class areas, where human activities are limited, adding the need for ecological protection makes the three land types the key ecological barrier. Spatial heterogeneity of landscape patterns and terrain are canonical correlation. The landscape indexes of forest and water are similar and their landscape heterogeneity degrees are lower; while the construction land, mining land, cultivated land and garden plot have higher fragmentation degrees because they mainly locate in plains and hills. The analyze result of CCA shows that the correlation coefficient of the first ordination axis of terrain factors and landscape indexes is 0.671, which means landscape patterns and terrain factors like elevation and slope have typical correlations.(3) This article determines the optimization layout partition of landscape by building ecological network of landscape. The ecological services of Huailai County shows significant differences in terrain, the most powerful region locates in the middle basin of Huailai County and Guanting reservoir is the core of landscape ecological services; After that are the woodland landscape that locate in the south and north mountains of Huailai County, where the forest is not rich but also concentrated continuous, which is important to ecological services; the weak service zones mainly locate in the areas of active human activities and hilly regions with unused land. Extracte the ecological barriars and ecological nodes using MCR model and then evaluate the importance of ecological nodes by d IIC and d PC, which help building the landscape ecological network and reflecting the impaction of ecological key zones to ecological flow. Against the ecological network, this article determines the optimization layout partition of landscape on the basis of comprehensive analysis of terrain features and distribution of ecological services, which can provide references for ecological optimization of land use in Huailai County. |
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