| The damage of urban surface landscape will lead to the loss of biodiversity to varying degrees.In order to explore the response of urban plant diversity to the change of landscape pattern,this paper picks the urban area surrounded by the round-city highway as the research object,sets 36 sample plots in different directions with the Gupeng Square as the center,investigates the plant group in each of the plots by use of typical sample plot method,and examines the features of the species diversity of plant groups in Xuzhou's greenlands.In the meantime,we divide the landscape of the research area into seven categories: buildings,grasslands,forest lands,waste lands,water areas,roads and farm lands supported by Erdas and GIS softwares and using Landsat TM remote sensing images of the research area in 2005 and 2015 as basic data source.The features of landscape pattern in the research area is also analysed with the use of Fragstats software.We have cut 9 different buffer districts within each of the sample plot by applying the space analyzing function of GIS,extracted 39 landscape metrics with the use of Fragstats,and explored the features that plant diversity responses to landscape pattern.The results are as follows:(1)There is a remarkable change of components of Xuzhou city's landscape,mostly featuring by a huge decrease of farmlands / desert lands and a huge increase of building / forest lands.The landscape pattern which dominates the area has changed from the farmland to the building land.The northwest and southeast of the research area has gained the largest portion of forest lands while losing the largest portion of farmlands.The northeast and southwest has gained the largest portion building lands while losing the largest portion of farmlands.The urban area of Xuzhou city increasingly extends eastwards and southwards,with the result of the annual change rate of building land,forest land,grassland,waste land,water area and farm land in the east and south of the city higher than that in the west and north of the city.(2)The degree of separation and fragmentation of landscape patches in Xuzhou city has increased,with a more diversified and evenly distributed landscape pattern,and a more complicated and regular characteristic of the shapes of the landscapeelements.The fragmentation degrees of water areas,building lands,grasslands and farmlands have increased,while those of the forestlands,waste lands and roads have decreased.There is a good connectivity in farmlands and water areas,with a low degree of landscape fragmentation and a relatively high connectivity metrics in all stages.(3)There are 308 species of plants belonging to 89 families and 234 genera in the group vegetation,as well as 25 species of artificial plants belonging to 12 families and19 genera.There are 288 species of grasses among which 15 species belonging to 7families and 12 genera are artificial.The wild grass species display a clearer picture of the features of pure natural species.(4)There is a scale effect in the response of species diversity to landscape patterns and elements.The response of species diversity to landscape elements has changed from the sole landscape to multiple landscape elements as well as more complicated mosaic structure of landscape elements.The response of species diversity to landscape patterns has changed from the sole landscape fragmentation metrics to several metrics regarding landscape fragmentation,landscape area,landscape shape and so on.The landscape pattern metrics of the research area in 2005 is more explicable to plant diversity and the response of plant diversity to the surrounding landscape pattern is delayed,which reflects the relation between the species distribution pattern at present and in the future and the landscape features in the early stage. |
PDF Full Text Request