Ecological Environment Assessment And Environmental Change Research In Tongwei-Zhuanglang Area Of Gansu Province

This paper focuses on the study of ecological environment vulnerability in typical loess hilly and gully region,taking Tongwei-Zhuanglang region of Gansu Province as the study area.With the support of remote sensing(RS)and geographic information system(GIS),using spatial principal component analysis(PCA)and mathematical statistics,the ecological environment vulnerability was evaluated from the regional scale,and the impacts of different index factors on the regional ecological environment were systematically analyzed,and the spatial and temporal evolution characteristics and vulnerability driving mechanism of ecological vulnerability in Tongwei-Zhuanglang were further discussed.The results are as follows:(1)The fragile degree of ecological environment in Tongwei-Zhuanglang Research Area of Gansu Province belongs to slight fragility.The distribution of ecological vulnerability in the study area has vertical and horizontal zonal characteristics.The overall trend is from southeast to northwest,and the vulnerability gradually increases.Below 1600 m,the vulnerability decreases with the increase of altitude,while above 1800 m,the vulnerability increases with the increase of altitude.(2)The ecological change trend in Tongwei-Zhuanglang region of Gansu Province can be divided into two periods.From 1998 to 2000,the potential and slight vulnerability decreased,while the moderate,severe and extreme vulnerability increased.From 2000 to 2018,the potential vulnerability decreased,the moderate vulnerability increased and decreased,the severe vulnerability fluctuated and the extreme vulnerability decreased.In recent 20 years,the ecological fragility of the study area has been decreasing,with slight fluctuations in the middle.(3)The eco-environmental vulnerability in Tongwei-Zhuanglang region of Gansu Province has been changing continuously in the past 20 years(1998-2018).Through the spatial principal component analysis,this paper analyzes several driving factors that influence the changing trend of eco-environmental vulnerability.Its direct driving factors include land use,vegetation cover,soil erosion and so on.Its potential driving force is due to the combination of rapid socio-economic development and environmental protection policies,such as the implementation of returning farmland to forests since 1999 and the corresponding measures to control soil erosion.(4)Summarized the research methods and processes of ecological vulnerability and environmental change in Loess hilly region,and provided methods and ideas for environmental research in similar regions,as well as theory and basis for regional ecological environment restoration.