The Dynamic Research On Landscape Pattern Of Urban Green Space And Parks Accessibility In Yanqing District

The 19 th National Congress of the Communist Party put the construction of ecological civilization in a more prominent position,proposing to strengthen the protection of the ecological system and insisting on the harmonious coexistence between man and nature.As an important part of urban ecological land,urban green space plays a vital role in the ecological environment and the well-being of residents.Yanqing District is an ecological conservation area established by the planning of Beijing's main functional area.By conducting research on landscape pattern of urban green space and parks accessibility,it can find existing problems,make reasonable suggestions,and better promote urban green space construction,which is conducive to form a green ecological security system pattern in Beijing.Taking the urban green space in central city of Yanqing as the research object,this paper makes a dynamic analysis on landscape pattern of urban green space from 2010 to 2018 from class-level and landscape-level;Constructing the accessibility index of park green space,the network analysis method is adopted to analyze the different characteristics of the accessibility of public park in Yanqing central city with three different travel modes of walking,bicycle and motor vehicle,dissecting the main problems faced by the urban green space spatial pattern and accessibility,and proposing optimization strategies.The main conclusions of this study are as follows:(1)The development of various green space types in Yanqing central city is not balanced.The area of public park has grown rapidly,and the area ratio has increased from 38.90% to 42.54%,becoming the dominant green space type.The change rate of the green buffer area is 20.69%,and the development speed is the fastest.The change rate of attached green space area is 2.12%,and the development is slow.The development of green space patches is mainly based on large and medium-sized patches and large patches,ignoring the construction of small and medium-sized green patches.The shape of green space tends to be regular.(2)The spatial distribution of urban green space in Yanqing central city is gradually balanced.The diversity index increased from 0.97 to 1.06,the evenness index increased from 0.89 to 0.96,the division index decreased from 0.98 to 0.94,and the aggregation index decreased from 99.11 to 98.99.The green space tends to be rationalized.The contagion index decreased from 55.71 to 51.87,and there was no good continuity between patches.(3)The accessibility of public park in Yanqing central city has been improved.The service area percentage of walking 10 minutes to reach the park increased by 6.55%,the service area percentage of bicycles reaching the park by 10 minutes increased by 3.95%,and the service area percentage of motor vehicles reaching the park by 10 minutes increased by 1.03%.Under different travel modes,the order of the accessibility of park for traveling 10 minutes is ranked as follows: motor vehicle > bicycle > walking.(4)The accessibility distribution of public park in Yanqing central city is unbalanced.Many public park is built on water,with good accessibility on both sides of Gui River and Sanli River,and poor accessibility in other areas.Although the accessibility improved in the later stage,the accessibility in the middle and the edge of urban area is still poor.