Spatio-Temporal Variation Mechanism Of Habitat Quality In The Yellow River Basin And Future Prediction Of Typical Areas

Habitat provides living space for species,and is an important indicator for measuring biodiversity.Stable habitats can reflect higher biodiversity.The Yellow River Basin is an important ecological barrier in China,which with a variety of ecological functions.Studying the spatiotemporal variation mechanism of habitat quality is of great significance for the high-quality development of the Yellow River Basin.Scientific and reasonable research on habitat quality and its driving factors in the Yellow River Basin can provide scientific basis for the evaluation of ecosystem service functions in the basin.At present,scholars have carried out research on the change of habitat quality in the Yellow River Basin,but there is a problem that the model application is highly subjective and the scale effect in the study area is not considered.In this study,the parameter adjusted InVEST model was used to calculate the habitat quality of the Yellow River Basin from 1995 to 2020.Its spatio-temporal variation and distribution characteristics were analyzed.Based on the landscape pattern index,the optimal analysis scale was calculated,and then the Geodetector was used to analyze the driving force of natural environment and socio-economic factors on habitat quality in the Yellow River Basin,and analyzing its time-related trends.Based on the strong correlation between habitat quality and NDVI,the principal component analysis method(PCA)was used to construct the landscape fragmentation index to screen the typical areas of habitat quality change in the Yellow River Basin.The Max ENT model was used to explore the future vegetation distribution under different shared socioeconomic pathways.The main research contents and conclusions are as follows:(1)The overall habitat quality of the Yellow River Basin showed a spatial pattern of “high in the west and low in the east”,and there were significant differences in the habitat quality patterns of the upper,middle and lower streams.The habitat quality of the upper streams of the basin is dominated by higher values and highest values,and most areas of the river source have remained stable for many years.The low-value habitats in the middle streams were mainly cultivated land and build-up land,while the median and higher habitats were mainly unused land,grassland and forest land,indicating that human disturbance had a more obvious impact on habitat quality.The habitat quality in the downstream areas showed a strong lowest-value cluster,and the non-habitat(0 value)area expanded significantly,which was mainly manifested in the decrease of habitat area caused by urbanization development and the increase of buildup area.From 1995 to 2020,the transfer between different levels of habitat quality in the basin was mainly from low grade to high grade,and the overall development trend of habitat quality was good.(2)The spatial variation characteristics of habitat quality are similar to the spatial distribution pattern.High-quality habitats were stable for many years in the source area of the Yellow River,and the increase mainly occurred in the upper streams and middle plateau mountains,and the decrease coincided with the road network.The change of medium-quality habitat mainly occurred in the middle streams of the bay-area,and the river valley plain in this area was obviously affected by human activities.The change of low-quality habitat mainly occurs downstream,affected by the urbanization procession,the decrease part is the transfer to non-habitat,and the increase part is inferred to be the intensive and concentrated use of cultivated land according to the change of land use,which is also significantly affected by human activities.(3)The optimal analysis scale of the driving factors of habitat quality change was3 km,and the influence of all geographical factors on habitat quality in the Yellow River Basin was significant.The factors explanatory force are sorted from largest to smallest:temperature,population density,altitude,landform,GDP density,slope,precipitation,impervious surface,and aspect.Temperature is the first dominant factor affecting the spatial differentiation of habitat quality,followed by population density.The total explanatory power of natural environment factors on habitat quality was higher than that of socio-economic factors,indicating that habitat quality was still mainly affected by geospatial patterns in the entire Yellow River Basin.The explanatory power of the interaction between the factors was higher than that of the single factor,showing a trend of interaction enhancement.The risk detection results showed that except for the insignificant situation between the aspect grades,and the insignificance between the middle altitude and the very high altitude of the altitude factor,the other driver factors were significant between the grades.(4)PCA was used to construct landscape fragmentation indexes,and six typical areas of habitat quality change were screened out,and the future distribution of key vegetation under different shared socioeconomic pathways(SSP126,SSP245,SSP585)was predicted.Haba Lake,Lingwu Baijitan,Ningxia Luoshan and Sanjiangyuan National Nature Reserves all increased in key vegetation growth suitable areas under the sustainable development path(SSP126),Shapotou National Nature Reserve increased the key vegetation growth suitable areas under the fossil fuel development path(SSP585),and Xunhua Mengda National Nature Reserve showed large results of unsuitable areas in each development path,but combined with the grading standards,the lowest probability of vegetation growth in unsuitable areas was 0.46,indicating that the whole protected area was suitable for the growth of key vegetation compared with outside the reserve.(5)Combined with typical areas current situation,the impact of human activities is much greater than the affect of natural environmental factors.The main contradiction of each national nature reserves lies in the balance between the development needs of indigenous people in the reserve and the ecological and environmental protection of the reserve.In view of the characteristics of different protected areas,it is suggested that ecological migration,poverty alleviation relocation,transformation of economic pillar industries,and exploration of protected area-community symbiosis mechanism can be used to reduce the interference of human activities on nature reserves while increasing residents’ economic income,so as to further improve the ecological protection benefits of nature reserves and promote the coordinated development of man and nature.