Spatiotemporal Variation And Driving Force Analysis Of Fractional Vegetation Cover In Agro-pastoral Ecotone Of The Yellow River Basin

Fractional vegetation coverage reflects changes in vegetation type,quantity and quality in terrestrial ecosystems to a certain extent,and is an important indicator of vegetation status.Taking remote sensing images from 1990 to 2020 as the basic data source in the research area of the interlaced area of agriculture and animal husbandry in the Yellow River Basin,the fractional vegetation coverage in the study area was estimated by using the pixel binary model,and the fractional vegetation coverage in the study area was calculated based on the actual fractional vegetation coverage in the study area.grades are divided.Matrix analysis was used to clarify the area change characteristics of all fractional vegetation coverage types from 1990 to 2020,the variation trend of fractional vegetation coverage in the region was analyzed by ridge regression function,and the Hurst index method was used to predict the variation trend of fractional vegetation coverage.The influence of human activities and climate on fractional vegetation coverage was analyzed by the methods of cumulative slope change rate and residual analysis,and the main driving factors affecting fractional vegetation coverage changes were analyzed.The main research conclusions are as follows:(1)Fractional vegetation coverage recovery area is much larger than the degraded area in the agro-pastoral ecotone of the Yellow River Basin,and the vegetation is restored as a whole,and the trend of restoration will be maintained for a period of time in the future.(2)Overall,the areas with different fractional vegetation coverage levels in the agro-pastoral ecotone of the Yellow River Basin were mainly transferred from low fractional vegetation coverage to medium-low and medium vegetation coverage.(3)After 2000,compared with 2000,the area where fractional vegetation coverage did not change significantly decreased by 49.28%;the elevation area increased by 53.11%,which fully shows that the implementation of ecological engineering has a promoting effect on the vegetation in the agro-pastoral ecotone of the Yellow River Basin.(4)The change of fractional vegetation coverage is affected by climate change and human activities.Human activities are the main reason for the change of fractional vegetation coverage in the agro-pastoral ecotone of the Yellow River Basin,and the contribution rate is 78.99%.The significant increase in fractional vegetation coverage in the region occurred mainly after 2000,thanks to a series of ecological restoration projects being implemented by the State.(5)Rainfall is the main climatic factor affecting the change of coverage in agro-pastoral ecotone of the Yellow River Basin.(6)Although this study can effectively calculate the impact of human activities on FVC,this study generally considers the complex human activities as a series of ecological restoration and reconstruction measures and urban construction behaviors implemented by human beings.We should further take into account the continuous impact of human activities on vegetation cover in the study area,such as population increase,forest,grassland,animal husbandry land use,and industrial development.The influence of climate factor FVC only studies temperature and rainfall.Although water use efficiency is the main factor driving the vegetation coverage change in the farming and pastoral areas of northern China,the influence of other climate factors such as solar radiation,surface wind speed and evapotranspiration on vegetation coverage is taken into account in this paper.Therefore,further exploration is needed in future research.In summary,the implementation of ecological restoration project has greatly improved the fractional vegetation coverage in the agro-pastoral ecotone of the Yellow River Basin.In contrast,the fractional vegetation coverage in the agro-pastoral ecotone of the Yellow River Basin is much larger than that in the degraded area,and the vegetation shows a recovery trend.Human activities played a positive role in increasing fractional vegetation coverage in the study area.Precipitation is the main climatic factor affecting fractional vegetation coverage in the study area.Although the influence of human activities and climatic factors on FVC was studied in this study,the research was relatively general.What specific influencing factors of human activities had not been studied,and only temperature and rainfall were studied for climatic factors,but other factors were not studied.It needs to be supplemented in future research.