Spatial Differences And Evolution Of Landscape Patterns Of Rural Residential Areas In Qinling-Daba Mountains

Rural residents refer to the rural residents'settlements with certain structure and function in the region.The spatial difference and time evolution of the landscape pattern such as quantity,scale and shape are the result of the interaction between natural environment and social economy at different stages.At this stage,although the proportion of urban population in China's total population has increased,the fact that number of rural population is large has not changed,and rural residential areas are still the way in which rural populations live.With the rapid development of the social economy,the economic advantages of the city center have attracted the continuous influx of rural population,and the contradiction between people and land has gradually deepened.At the same time,the outflow of population in rural areas has made the phenomenon of?hollow villages?not uncommon,resulting in the rational use of cultivated land resources.In addition,the inherent attributes of rural settlements——multiple quantity,wide distribution,and small scale——have made the regional planning system difficult to formulate or difficult to implement,which has limited the development of rural residential areas to a certain extent.Based on the rural residential data in Qinling-Daba Mountains of southern Shaanxi,this study uses the landscape index,sensitivity analysis and information loss evaluation method to explore the grain size curve effect,sensitivity and predictability of rural residential point density,scale and morphological characteristics,and combine information loss value to determine the optimal particle size value.Based on this,GIS spatial analysis model is introduced to establish the close relationship between landscape and landscape,and to reveal the regional differences and temporal evolution characteristics of rural residential space from a macro perspective.Quantitative analysis of the above-mentioned landscape pattern differences and the evolution of the natural environment and socio-economic factors by means of multi-level buffers and binary logistic regression models.The main results are as follows:(1)There are differences in the grain size curves of different landscape indices.As the size of the granularity space becomes larger,NP,PD,LSI,COHESION and MSI decrease monotonously,SPLIT fluctuates downward,MPS and PSSD increase monotonously,CA changes weakly,and LPI fluctuates sharply.The sensitivity and predictability of the particle size effect of each landscape index are significantly different.CA and MSI are insensitive index(CV<10%),MPS and COHESION are sensitive index(CV>30%),NP,PD,LPI,PSSD,LSI,SPLIT are moderately sensitive index(10%<CV<30%),except for CA and LPI,the other indexes are better predictive(R~2>0.90).According to the optimal particle size selection rules,the optimal particle size of the rural residential point density and scale index in different periods is 45m,and the optimal grain size index is 30m.(2)The number of rural settlements per unit area in the study area has increased in the past 15 years.The spatial distribution patterns of different periods are all significant agglomeration characteristics,and the degree of agglomeration is gradually increased.The density distribution is a spatial feature of?high density,multi-core accumulation,low density and wide distribution?,and high value areas are mainly concentrated in the northern part of Zhouzhi County,Hantai District and the central part of Chenggu County.Density characteristics in different periods are expressed as transformations between types and aggregated to"advantage"types.The total area of rural residential areas has gradually increased,the characteristics of high value and high concentration are significant,and the spatial differences are more obvious.There is a positive correlation between the scale and density spatial distribution,that is,high-density large-scale agglomeration distribution,low-density small-scale agglomeration.With the change of time,the shape characteristics of rural settlements are more complicated,and the continuity is improved,but the degree of dispersion in some areas is slightly increased.In addition,the type of landform is closely related to the morphological characteristics of regional rural settlements.(3)All factors have an impact on the landscape pattern characteristics of rural residential areas.Rural residential areas in the plain basin area are characterized by large-scale,high-density and complex shapes.Appropriate area for rural residents living at an altitude of less than 1000m and a slope of less than 5°.As the river distance increases,PLAND,NP,KDE and MPS in rural residential areas decrease monotonically,MSI fluctuation decreases.The urban center and traffic conditions are within the range 0 to 3km,the characteristics of?predominant species?in rural residential areas are obvious,and the impact is no longer significant more than 12km.The higher the proportion of cultivated land area and the denser the population distribution,the larger the rural residential area,the higher the density and the more complicated the shape.The influencing factors of the density evolution of rural residential areas are landform type,slope,river distance,convenient transportation,proportion of cultivated land and spatial distribution of population,the influencing factors of scale evolution are landform type and slope,the influencing factors of morphological evolution are the distance from the river and the convenient transportation conditions.In summary,this study systematically analyzes the spatial differences and evolution characteristics of the landscape pattern of rural residential areas in the study area from the aspects of density,scale and morphology.It is estimated that the number of rural residential areas in the study area has increased,the scale has expanded,and the form has become more complicated in the past 15 years.Combining the influential factors that can be obtained,it is concluded that Plain basin area is the dominant region for rural residents to gather,the landscape characteristics of rural residential areas have obvious near-water source,the urban center and traffic conditions have strong attraction and directivity to the landscape characteristics of rural residential areas,the landscape characteristics of rural residential areas are proportional to the proportion of cultivated land and the spatial distribution of population.This study can provide a theoretical basis for the optimization of regional rural residential areas and regional planning.