| Vegetation is the carrier of species and the place where plant resources depend for survival.The overall condition of vegetation comprehensively reflects the ecological background of the country and region.It is an important basis for biodiversity protection,ecological restoration and the formulation of land use policies.The ecological "green-core" area of Changzhutan urban cluster(hereinafter referred to as "green-core" area of Changzhutan)is located in the center of red soil hilly region of Southern China.Known as the "lung of Changzhutan","green-core" area of Changzhutan is an important intercity ecological barrier and plays multiple ecosystem functions.The vegetation in the area is dominated by secondary forests,and the vegetation types are complex and diverse.Most of the studies are about spatial planning and ecosystem,and there are few vegetation ecological studies combined with the field.However,the vegetation types and spatial distribution in the region are not fully understood.Guided by the compilation and research standard of Vegegraphy of China,based on 257 quadrat data.uses the methods of kilometer grid,quadrat survey and vegetation sample record to construct a vegetation classification system of"green-core" area of Changzhutan,and describes the community species composition and structural characteristics of main vegetation types.Based on multi-source sample collection,Cram-Schmidt Pan Sharpenin(GS)of sentinel-2 multispectral remote sensing image and high-resolution satellite map,image interpretation of random forest model,arrangement of legend system and color matching system,the 1:50000 vegetation map of "green-core" area of Changzhutan is drawn by ENVI,ArcGIS and other software.Then the spatial distribution pattern and characteristics of vegetation types were analyzed.The main results were as follows:(1)There are rich and diverse vegetation types in "green-core" area of Changzhutan.The natural vegetation are divided into 4 vegetation formation groups,10 vegetation formations,10 vegetation subformations,26 alliance groups,47 alliances,79 association groups and 113 associations.The cultural vegetation are divided into 2 platations,8 types,13 subtypes and 23 forests(orchard).Among all the vegetation types,there are 10 vegetation formations,22 alliances and 33 associations are more typical and general.(2)The forest covers a large area and is seriously fragmented,same as shrubs and grasslands.Grain,fruit and economic forest are concentrated in a large area.Among the 7 vegetation formation groups in vegetation map of first-level unit,the area of grain,fruit and economic forest is the largest(45.77%),followed by forest(31.66%)and non vegetation(20.24%).The forest has the largest number of spots(55.83%),followed by grain,fruit and economic forests(25.77%)and non-vegetated area(16.25%).The urban vegetation has the largest average area of one spot(27.77 hm2),followed by grain,fruit and economic forest(18.89 hm2),forest and shrub are the smallest(6.03 hm2 and 5.22 hm2).(3)Evergreen broadleaf forest is the main type of natural forest in the region with serious fragmentation.The herb-horticulture type has the largest area and is concentrated in the northeast.Among the 19 vegetation formations in vegetation map of second-level unit,the area of herb-horticulture type is the largest(26.57%),followed by non vegetated areas(20.24%)and evergreen broadleaf forest(16.76%).The evergreen broadleaf forest has the largest number of spots(23.94%),followed by the non vegetated section(16.25%).The herb-horticulture type has the largest average area of one spot(45.69 hm2),followed by urban composite vegetation(27.77 hm2),deciduous broadleaf forest and bamboo forest are the smallest(3.24 hm2 and 2.79 hm2).(4)The area of Cinnamomum camphora evergreen broadleaf forest is the largest and widely distributed in the area,other types are mostly scattered.Nursery orchard is the largest alliances type,which is concentrated in the northeast.Among the 47 alliances(alliance groups)in vegetation map of third-level unit,the area of nursery orchard is the largest(26.57%),followed by Cinnamomum camphora evergreen broadleaf forest(13.26%)and buildings&bare land(13.06%).The Cinnamomum camphora evergreen broadleaf forest has the largest number of spots(18.59%),followed by buildings&bare land(8.70%)and Camellia oleifera plantation(7.83%).The urban park compound vegetation and nursery has the largest average area of one spot(46.31 hm2 and 45.69 hm2).The vegetation in "green-core" area of Changzhutan has the regional characteristics of richness,integrity,typicality,rarity and fragmentation.On the one hand,the results provide effective background data for regional biodiversity protection,plant resource monitoring and protection evaluation.Overall,provide scientific basis for regional vegetation restoration,functional zoning and sustainable development planning.On the other hand,this paper provide reference for the drawing of large-scale vegetation map. |
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