Habitat Quality Assessment Of Tianfu New Area Based On CLUE-S And InVEST Model

Tianfu new district is a state-level new area to respond to the strategy of "one belt and one road".Its establishment not only changed the original urban structure of Chengdu,but also eased the pressure of the old urban area.In recent years,due to the strong interference of human activities,the natural ecological environment of Tianfu New Area has undergone tremendous changes,mainly reflected in the change of regional land use pattern.Changes in land use patterns will lead to changes in regional ecosystem types,which may lead to the destruction of habitat quality.This paper establishes a time series-based evaluation system of habitat quality,which is arises out of significance to regional land planning and ecological planning,and provides theoretical support for the construction of ecological security pattern and the realization of regional sustainable development in Tianfu New Area.This paper takes Tianfu New Area as the research object,focusing on the evaluation and dynamic analysis of the overall habitat quality in the region.Based on the data of remote sensing images in 2012 and 2016,two periods of land use data were obtained by using object-oriented classification method in Yikang software.The trend of future land use change was predicted by using the CLUE-S model.Based on the pattern of land use change,the habitat quality assessment module of InVEST model was used to discuss the whole progress situation of Tianfu New Area in recent years.The law of habitat quality changes.The main conclusions are as follows:(1)In terms of land use type change,from 2012 to 2025,with the acceleration of urbanization in Tianfu New Area,the area of cultivated land,forest land and garden land decreased year by year,which decreased by 59.73 km2,79.76 km2 and 87.3 km2 respectively.Urban land and traffic land increased year by year,which increased by 87.18 km2 and 76.24 km2 respectively,grassland increased by 77.71 km2,and water area changed little.(2)InVEST model simulation shows that the overall index of habitat degradation in Tianfu New Area is low,but the degree of degradation is increasing year by year;the index of habitat quality is decreasing year by year;the score of habitat scarcity index is higher,but the two periods change obviously,compared with 2016 and 2025,the habitat scarcity in Tianfu New Area is greatly improved.(3)According to the three indices of InVEST model,different weights are defined to evaluate the overall habitat quality of Tianfu New Area.The results show that the overall habitat quality of Tianfu New Area is poor,and the overall habitat quality is related to land use types.According to land use types,Tianfu New Area is divided into seven categories.Overall habitat quality score of Tianfu New Area is less than that of cultivated land and garden land,and higher is woodland,water area and grassland.The overall habitat quality of Tianfu New Area shows an inverted "N" distribution under different topographic gradients.The overall habitat quality of Tianfu New Area is mainly concentrated in low gradient(1-3)and middle-high gradient(6-8).The habitat quality of middle-low gradient(5-6)and the maximum gradient(9-10)was the worst,and the lower gradient was the dominant.The overall habitat quality of gradient 8 was the highest,mainly because gradient 8 distributed a large number of woodlands,and the two-stage gradient distribution data showed that each gradient had degenerated.Therefore,in the seven counties(districts and cities)of the study area,the main land use types of Janyang City and Pengshan District were studied.For waters and woodlands,the overall habitat quality is the best.On the contrary,the overall habitat quality is the lowest in areas adjacent to the main urban area of Chengdu and with rapid urban development(high-tech zone,Tianfu New District,Chengdu Direct Management Area).In view of these problems,we should pay attention to the allocation of vital ecological land on the premise of ensuring economic growth in future planning work.In the process of urbanization,we should properly control the spatial form of cities and towns,try to avoid inefficient fragmentary expansion of construction land,while protecting ecological "source" areas and strengthening the construction of ecological corridors.