A Study On The Interaction Between Mountain And Urban Space Development In Guiyang

Under the background of urbanization,a large number of natural mountains are embedded in the built-up area in the process of urban expansion,forming a typical city mountain mosaic landscape of "city in the mountains,mountains in the city".However,there is no research report on the relationship between mountain and urban space in the process of urban expansion.In order to explore the interactions between natural mountains and urban spatial development in mountainous cities,Guiyang,a typical mountainous city,was selected as the research object.Based on the remote sensing interpretation data of 2008,2013 and 2018,Arc GIS spatial analysis technology,mathematical statistics,landscape pattern index,In VEST model and plant diversity index were used,This paper analyzes the impact of urban natural mountains in different periods on the spatial expansion of Guiyang City,the impacts of natural mountains in built environment on urban construction land,and the impacts of urban internal densification on natural mountains.The results showed that:(1)From 2008 to 2018,the construction land expansion in the central urban area of Guiyang was fast and intense,and the urban diffusion trend continued.As a typical mountain city,the urban expansion was restricted by the natural mountains in the process of urban expansion in a "flooded network" mode,which created the unique urban style of Guiyang with "mountains within the city and city between the mountains".The compactness and fractal dimension of the central urban area had decreased year by year,the urban development was not compact in the process of urbanization,and the utilization efficiency of internal resources was low.From 2008 to 2018,the spatial differentiation characteristics of natural mountains in Guiyang were as following: large mountains or continuous mountains were mainly distributed in the western,southeastern,and southern periphery of the built-up area,while relatively small natural mountains were scattered sporadically in the city.The quantitative characteristics of the natural mountains in different periods showed that the small ones were the main ones in the early stage,the large ones were gradually dominant in the later period,and the medium ones were relatively stable.The spatial expansion pattern of the built-up area was obviously shaped by the natural mountains.The city spread along the boundary line of the mountains to the flat area.The continuous mountains in the west,northeast,and south blocked the expansion of the city,resulting in the "Y" shape expansion pattern of the city.Natural mountains have a restrictive effect on the directions of urban spatial expansion.The directions with a large proportion of natural mountain area have a low urban expansion intensity,while the directions with a high urban expansion intensity have a small proportion of natural mountain area.(2)From 2008 to 2018,construction land in central Guiyang was mainly distributed in flat areas,and the construction land in relatively undulating areas decreased sharply.The distribution advantage of natural mountains in relatively undulating areas was greater than that of construction land,indicating the adaptability of construction land in urban spatial development to topography.Overall average artificial green space ratio and construction land proportion increases over time,and buffer gradient matching relations were 2008 > 2013 > 2018,but for the same batch into the city natural mountains,along with the time changes of urban construction land accounted/urban artificial green space ratio and buffer gradient fitting relationship,there was no obvious regularity;The spatial locations of natural mountains of different patch types were significantly correlated with urban construction and development,with the small and medium-sized mountains in the central region having the highest correlation and the large mountains in the edges of built-up areas having the lowest correlation.The degree of integration around the mountains increased with the passage of time,and the degree of integration decreased with the increase of distance from the city center.In mountainous cities,the interaction between urban natural mountains and urban construction and development are obvious.In the process of urban expansion,the natural mountain,as a constraint factor,will be occupied by continuous excavation.On the other hand,as an important ecological resource in urban construction,the natural mountains will have a certain attraction to urban construction.(3)The general characteristics of land use change in the central urban area of Guiyang from 2008 to 2018 were as follows: natural mountains,cultivated lands and construction lands constituted the main body of land use types in the central urban area of Guiyang,and the transformation of cultivated lands and natural mountains was the main source of construction land expansion;The urban construction lands continued to increase from 2008 to 2018,and the expansion of construction lands was mainly caused by the conversion of cultivated lands,natural mountains and unused lands.The change of natural mountain areas showed a trend of decreasing at first and then increasing with the urban construction intensity.From 2008 to 2018,the overall landscape pattern in the construction areas of Guiyang continued to be broken,patches tended to be homogenized,different landscape types cut each other seriously,and landscape connectivity decreased.The effect of rapid urban expansion on the landscape pattern of urban natural mountains was mainly reflected in the reduction of the number and area of patches,the regularization of patch shape,the decrease of connectivity,the spatial cluster distribution,and the decrease of the stability of landscape pattern.Urban heritage natural mountain is the most important contributor to these areas in Guiyang city habitat quality factor,and is liable to suffer from stress of landscape type city environment.The temporal and spatial evolution of Guiyang city-mountain landscape habitat is synchronous.The city-mountain habitat quality increasing outward from a center,the city-mountain habitat degradation decreasing outward from a center,city-mountain habitat quality change is closely related to the urban land use type transformation.The spatial morphological indices is positively correlated with the mountain plant diversity,and the responses of connectivity degree,integration degree and road density are more comprehensive and specific.The correlation increased with the expansion of spatial scale.Rational urban construction in a certain range could promote the mountain plant diversity.