Study On The Heterogeneity Of Farmland Landscape In The Lower Liaohe Plain Based On The Moving Window Method

Landscape heterogeneity is the hot spot in the research of landscape ecology at present.It is the basis of optimizing the allocation of resources and the function of structure in the landscape.The farmland landscape is the product of the long-term management of land,and it is also the most basic material production department for human existence.The high agricultural ecosystem and the stability and efficiency of agricultural production provide a strong basis for the scientific layout and effective management of farmland.In this paper,the Liaohe plain area is the research area.Based on the basic principles of landscape ecology,with the help of ArcGIS 9.3,Fragstats3.3 and GS+7 software,geostatistics,mathematical statistics and landscape heterogeneity are used to analyze the overall pattern and spatial heterogeneity of farmland landscape in the study area.Firstly,based on GIS technology,the farmland landscape type in the Liaohe plain area is divided.Secondly,the index of representative landscape heterogeneity is selected from the type level and landscape level,and the grain size is determined by regional area information conservation evaluation method.The amplitude is determined by the method of moving window combined with semi variant function,and then the farmland landscape in the study area is determined.Secondly,the landscape pattern and gradient change of the lower reaches of Liaohe Plain were analyzed from the level of patch type and landscape level.The main results are as follows:(1)the landscape pattern index is more sensitive to the scale response.This paper determines the size of the 45 m grid and the amplitude of 850 m moving window is the characteristic scale of the farmland landscape pattern and heterogeneity analysis in the lower Liaohe plain,and the analysis method is helpful to provide reference for the determination of the spatial heterogeneity of the landscape in the similar research area.(2)the pattern characteristics of the farmland landscape in the lower Liaohe Plain are as follows: on the type level,the cultivated land is the landscape matrix,followed by the woodland,the rural residential land and the water landscape,among which the woodland patches are mainly with the high canopy density,and the rural road,the woodland and the grassland are more complex,and the inland beach and shrub.The shape of woodland is relatively regular,and the overall diversity of farmland landscape is relatively high in landscape level,and the spatial connectivity of patches is better,but the degree of distribution homogenization is more general;in natural landscape,the degree of grassland fragmentation is the highest,followed by river water,forest land and other forest land,while land beach and shrub land are broken.The degree is relatively low.In the artificial landscape,the degree of fragmentation of rural roads and ditches is the highest,while the degree of fragmentation offarmland,orchard and reservoir ponds is relatively low.(3)on the distribution of landscape spatial heterogeneity,heterogeneity is high in the East and west of the lower Liaohe Plain(hilly area),in the middle of the central water system(Liaohe River and its tributaries),while the low value of heterogeneity is concentrated in the central plain(typical agricultural region with cultivated land),and the type of farmland landscape in the high heterogeneity area More abundant,the spatial structure is relatively complex,the non tillage landscape(forest land,shrub forest land,grassland,river water surface,reservoir pit,inland Beach)is more and more evenly distributed in farmland.However,the landscape elements in the low value area are relatively single,the spatial proportion is not balanced,and the superiority of cultivated land and rural residential areas is relatively high.The number and spatial configuration of non tillage landscape determine the heterogeneity level in farmland landscape.(4)on the gradient of spatial heterogeneity,the landscape diversity and fragmentation index have different regularity along the direction of the 4 samples.In the high altitude mountain area,the large-scale urban fringe area and the large river corridor,the coastal index fluctuates more violently,and the amplitude is positively correlated with the height of the river and the distance from the river flow and the city center.The index fluctuation of the farming area in the Central Plains tends to be slow,and the heterogeneity of farmland landscape is affected by the topography and geomorphic features,the distribution of surface water resources,the intensity of cultivated land development and the economic development of the city.