Delimiting The Radiant Belt Toward Land Of Lake-Terrestrial Ecotone With Natural-wetland Type And Exploring The Influencing Factors

Lake-terrestrial ecotone with natural-wetland type is the basic r eference type for lake-terrestrial ecotone restoration.As an importan t part of lake-terrestrial ecotone with natural-wetland type,the radiat ion belt toward land delimited from the annual average highest wat er level toward land to some extent.The complexity and transitivity shared by lake-terrestrial ecotone made it hard to delimit.In order to research the the method of delimiting the width of terrestrial ra diation zone in natural lake-terrestrial ecotone.Took eastern lake are a(Taihu Lake,Changtan Reservoir,Xiazhu Lake),northeast lake ar ea(Xinmiao Pao,Chagan Lake,Yueliang Pao),Qinghai-Tibet lake area(Baksum Lake,Yambdroktso,Namtso,Siling Co)as examples,based on the understanding of the spatial structure characteristics o f lake-terrestrial ecotone,calculated the squared euclidean distance(SED)with the important value(IV)of hygroscopic herbaceous plant s,used the moving split-window technology(MSWT)delimited the width of the terrestrial radiation zone in the lakeside zone,and exp lored the factors that affect width from different spatial scales.The r esults showed:the widths of the radiant belt toward land of lake-te rrestrial ecotone with natural-wetland type of Taihu Lake,Changtan Reservoir and Xiazhu Lake were 15-19 m,19-31 m,and 17-21 m;the widths of the radiant belt toward land of lake-terrestrial ecotone with natural-wetland type of Xinmiao Pao,Chagan Lake,Yueliang Pao were 17～35 m,29-47 m,37～71 m;the widths of the radiant b elt toward land of lake-terrestrial ecotone with natural-wetland type of Baksum Lake,Yambdroktso,Namtso,Siling Co were 51m,56 m,33～53 m,19～31 m.Started from the large spatial scale containing 3 lake areas and the small spatial scale of the same lake area contai ning only one lake area,used correlation analysis and redundancy a nalysis to determine the relationship among width,climatic factors,topographic factors,soil physical and chemical properties,richness a nd diversity of plant communities.This study showed that MSWT can accurately delimite the range of terrestrial radiation zone in nat ural lake-terrestrial ecotone.On a large spatial scale containing 3 la kes,climatic factor(average annual temperature)and topographical fa ctors(altitude,slope)were the main factors affecting the width of the radiant belt toward land of lake-terrestrial ecotone with natural-wet land type;on the small spatial scale of the same lake area,the so il moisture content was the most important factors for tthe width of the radiant belt toward land of lake-terrestrial ecotone with natural-wetland type,slope,soil pH,and soil nutrient content all had a ce rtain influence on the width.