Evaluation And Optimization Of Urban Ecological Resilience Based On Landscape Pattern

Since the reform and opening up,the rapid development of Guangzhou’s economy and the continuous promotion of urbanization have led to a series of ecological and environmental problems,threatening the urban ecological security.The concept of ecological resilience provides an important solution to deal with the internal ecological pressure accumulated in the process of urban economic and social development and the impact of external uncertain ecological risks,and to build a good ecological environment.Therefore,how to quantitatively evaluate the urban ecological resilience of Guangzhou based on the concept of ecological resilience,and deeply explore the spatial-temporal differentiation characteristics under the micro scale,so as to provide optimization strategies and suggestions for the improvement of urban ecological resilience,which is of great significance to accelerate the construction of ecological civilization in Guangzhou and achieve the goal of regional sustainable development.Based on the landsat-8 remote sensing images of Guangzhou in recent 40 years,this paper analyzed the characteristics of land use evolution and landscape pattern of Guangzhou from1980 to 2018;From the perspective of landscape pattern,this paper attempts to build an evaluation model framework of urban ecological resilience in Guangzhou based on pressure state response,analyzes the corresponding levels and spatial pattern characteristics of ecological pressure disturbance,structural state and functional response in Guangzhou by using mathematical statistics and spatial analysis,and focuses on the spatiotemporal differentiation characteristics and evolution rules of urban ecological resilience;In order to improve the future urban ecological resilience,three scenarios of "ecological protection","suitable construction" and "planning restriction" were set up based on the different possibilities of urban development mode,and the landscape distribution pattern under different scenarios was simulated with the help of CLUE-S spatial optimal allocation model,and the ecological resilience situation under different scenarios was analyzed;Based on the results of the previous analysis,combined with the theory of ecological resilience and landscape ecology,this paper puts forward the optimization strategies and suggestions to enhance the urban ecological resilience.The results show that:(1)Woodland and cultivated land are the main types of land use in Guangzhou.With the rapid expansion of the unnatural landscape,the area of ecological land has reduced to varying degrees.Especially since the beginning of the 21 st century,the conversion frequency and types of different land use types are becoming more and more complex,which leads to the continuous reduction of natural ecological space and the fragmentation of structure.At the same time,the connectivity and stability of the overall regional landscape are declining,and the contradiction between urban people and land is becoming increasingly prominent,which brings great pressure to maintain the regional ecological balance and habitat quality in Guangzhou.(2)Based on the theory of ecological resilience and from the perspective of landscape pattern,the evaluation model of urban ecological resilience in Guangzhou can better reflect the ability of urban system to cope with the disturbance and threat of uncertain ecological risks under the intervention of human and natural ecological processes.In the past 40 years,the ecological resilience level of Guangzhou city is at a low level as a whole.Affected by the continuous interference of ecological pressure,the continuous decline of ecological structure and the fluctuation of ecological service function,the ecological resilience of Guangzhou city shows a fluctuating downward trend.(3)Influenced by the natural conditions and the distribution pattern of landscape types,Guangzhou’s urban ecological resilience shows significant spatial heterogeneity,with the spatial distribution pattern of "low-lying and low-lying,high in hilly areas,superior in the north and inferior in the South".Among them,the low toughness area accounts for a high proportion of the whole,and is distributed in the landscape types such as construction land and cultivated land;The forest landscape ecological barrier area has always been a stable area with high ecological resilience.With the expansion and spread of construction land landscape,low resilience areas tend to be consistent with the synchronous expansion.(4)The CLUE-S spatial optimal allocation model can better simulate the landscape pattern optimization under different development scenarios of Guangzhou in the future.Among them,the ecological structure advantage of "ecological protection" scenario is obvious,and the spatial integrity is the best,so the overall ecological resilience level of the city is the highest.In the non ecological protection scenario,the ecological land in the central part of the city is still threatened by the expansion of construction land,and the ecological resilience is obviously weakened.For the pressure of ecological environment faced by Guangzhou City,ecological protection scenario is the inevitable choice for the future development of the city.(5)Based on the quantitative evaluation and scenario simulation analysis of urban ecological resilience,it is an important way to realize the optimization of urban ecological resilience pattern to reasonably allocate and optimize the basic elements of landscape pattern,such as patches,corridors and bases.The ecological patch area and patch density increased;Ecological corridor construction,protection and widening;Strengthening the protection and restoration of ecological basement space,controlling the area and shape of non ecological patches are conducive to the improvement of ecological resilience and the support and mitigation of ecological risks.The results provide important scientific basis for guiding the construction of Guangzhou ecological security spatial pattern,promoting the construction of urban ecological civilization and regional sustainable development,and providing innovative path for urban land resource planning and case support for other urban ecological civilization construction.