Spatial And Temporal Changes Of Mountains,Rivers,Forests,Farmland,Lakes And Grasslands And The Health Evaluation Of Life Community In The Xijiang River Basin Of Guangxi

The river basin is a life community of mountains,rivers,forests,farmland,lakes and grasslands,and it is made up of natural geographical factors and human factors,such as forest land,cultivated land,lakes,and grasslands.The health status of the river basin's ecological environment is affected by social and economic activities.How to scientifically and accurately evaluate the river basin health and propose restoration measures is the guarantee for the coordinated river basin health and it is development.At the same time,it is also an urgent problem to be solved in ecological restoration.This article takes the Xijiang River Basin of Guangxi as an object.Firstly,build a health assessment indicator system for life community of mountains,rivers,forests,farmland,lakes and grasslands.Secondly,the elements of the life community of mountains,rivers,forests,farmland,lakes and grasslands are identified,and then their evolutionary laws are analyzed.The comprehensive index method is used to evaluate the health status of the life community and the subsystems of the mountains,rivers,forests,farmland,lakes and grasslands.Finally,the geographic detector model was used to quantitatively analyze the factors affecting the health of the mountains,rivers,forests,farmland,lakes and grasslands of life community.The results show that:(1)The distribution of the elements of the life community of mountains,rivers,forests,farmland,lakes and grasslands at different altitudes,slopes and geological features is significantly different.Mountainous areas are mainly concentrated in the west and north of the basin.The waters are mainly distributed in the central and southern parts of the basin.Forest land is concentrated in the northwest and northeast of the basin.The farmland is mainly concentrated in the central and southwestern parts of the basin.Grassland is scattered in the watershed,and the grassland area is wider in the north-central area.In terms of different altitudes,waters,farmland,and lakes are mainly distributed in areas with an altitude of less than 300 meters.In terms of different slopes,waters and farmland are mainly distributed on flat slopes and flat areas.Forest land is mainly distributed in slopes and gentle slopes.Grasslands are mainly distributed in slopes and flat areas.Lakes are mainly distributed in flat slopes and gentle slopes.The waters,woodlands,farmland,lakes,and grasslands in the Xijiang River Basin of Guangxi are mainly distributed in non-carbonate areas.The area of water and woodland in non-karst area is larger than that in karst area,while the area of field and grassland in karst area is larger than that in non-karst area.(2)The elements of the life community of mountains,rivers,forests,farmland,lakes and grasslands change over time.In 2015,the water area was 2806.15 km~2,accounting for 1.38%.The woodland area is 135884.46 km~2,accounting for 66.99%.The farmland area is 41808.66km~2,accounting for 20.61%.The lake area is 2.71 km~2,accounting for 0.001%.The grassland area is 17932.92 km~2,accounting for 8.84%.From 2000 to 2015,the area of woodland,farmland and grasslands decreased,the area of lakes remained basically unchanged,and the area of water areas increased.(3)The average value of the health index in the life community of mountains,rivers,forests,farmland,lakes and grasslands in the Xijiang River Basin of Guangxi is 0.52,which is in sub-health.The area of sub-health level accounts for 67.54%,the area of health level accounts for 32.33%,and the area of unhealth level accounts for 0.13%.The health levels of different subsystems are significantly different.The health status of the mountain subsystem and forest subsystem is very good,the health status of the water subsystem and human subsystem is average,and the health status of the farmland subsystem and grasslands subsystem is poor.According to the simulation results of the geographic detector model,soil type,surface temperature,comprehensive treatment area of soil erosion,fixed asset investment,are the main factors affecting the health of life community.