Research On Biodiversity Evaluation And Protection Of Nansi Lake Basin Based On InVEST Model

Habitat quality determines the capacity of regional biodiversity conservation,and assessing the response of regional habitat quality to land use changes can indirectly measure the temporal and spatial changes of regional biodiversity maintenance function and provide a quantitative reference for biodiversity conservation.GIS,RS,GPS and related ecosystem service models provide strongly technical support for the study of biodiversity.In this paper,the InVEST-Habitat Quality model was used to simulate the temporal and spatial changes of habitat quality in Lake Nansi Basin from 1980 to 2015.The spatial and temporal distribution characteristics of habitat quality in Lake Nansi Basin were analyzed by ArcGIS,and the priority conservation areas of biodiversity were analyzed in combination with established nature reserves at all levels to provide reference for the research on biodiversity conservation in the basin.Then evaluates and protects the biodiversity of the Lake Nansi Basin.Simulating changes of biodiversity under different development models.Then evaluates and protects the biodiversity of the Lake Nansi Basin.Set up two different scenarios of urbanization process and ecological protection measures to study changes of habitat quality and biodiversity.The main conclusions of this research are as follows:(1)The cultivated land,forest land and grassland were transformed into a large number of construction land during 35 years,urban land increased by 40.23% as well as lake area decreased by 35.56% which were mainly converted into reservoir pond.The analysis of the landscape pattern index in the past 35 years shows that the landscape twists and turns in the Lake Nansi Basin have increased due to the strong human interference,the fragmentation has become increasingly seriously,the ability of anti-interference has been weakened,the stability of the ecosystem has been reduced as well as the biodiversity.SHDI and SHEI increased in the last 35 years,landscape types develop towards diversification,and the intensity of human transformation of nature became deeper and deeper.(2)The overall habitat quality of the Lake Nansi Basin is at a low level from 1980 to 2015 due to the rapidly development of the industrial and agricultural production as well as the expanding urban land use in the past 35 years.The difference of the intensity of the environmental protection and the intensity of human activities led to the spatial distribution of habitat quality showed the trend of western plain area<eastern hilly and mountain area< Lake Nansi area.The expansion of urban and industrial areas undermines the existing habitat and become the major factor reduction habitat quality.The habitat quality of different terrains is characterized by mountainous land> plateau> hilly> plains,with average habitat quality of 0.49,0.31,0.28 and 0.18.The correlation analysis shows that the nagative correlation between habitat quality and urban areas in the Lake Nansi Basin is the highest,reaching-0.974.(3)In the past 35 years,the area of highly Habitat Rarity is mainly in the lake area and the eastern hilly area of the basin.However,the Habitat Rarity index in some marginal lakes is very low,which is disturbed by human activities.The main reason is that Lake fisheries farming and agricultural activities.Quantitative assessment of the effects of urbanization and ecological protection on the quality of habitats.The process of urbanization reduced the habitat quality of the area.The urban buffers of 100 meter,300-meter and 500-meter reduced the habitat quality by 1.11%,2.83%,and 4.29%.Ecological protection has improved the quality of habitats greatly.Returning farmland to forest and wetland in the lake area could increase the average habitat quality by 9.21% while that returning farmland to forest in the hilly area could increase the average habitat quality by 16.75%.This study can provide theoretical and policy guidance for biodiversity conservation in the Lake Nansi Basin and provide a theoretical basis for basin ecological planning,promoting the sustainable development of Lake Nansi Basin.