Comprehensive Evaluation Of Landscape Ecological Security In Zhuhai City

Research on the urban landscape ecological security issue mainly focuses on the ecological problem which caused by the urban landscape change.People’s livelihood and sustainable development depend on the urban landscape ecological security.This research studies the landscape pattern change,urban ecological security status and the ecological security network pattern from the aspect of landscape ecology and the urban ecological security by using 3 S technology.The data source include the four time stages remote sensing images interpretation data,classified into 7 different land use types,they are the year of 1999,2005,2009 and 2013.The three parts of research are based on the landscape pattern index calculation,the single factor analysis based on the PSR(pressure-state-response)model and the ecological corridor network analysis based on the minimum distance theory.The main contents include:1.Landscape pattern change analysis:This research analyze 14 years of the landscape index change of the Zhuhai city from 1999 to 2013.The results shows that the number of patches of Zhuhai on the landscape pattern levels increased,so as to the landscape fragmentation,landscape diversity,and distribution area uniformed.From the aspect of the landscape index of each time stage,the landscape pattern of Zhuhai is continually tends to fragmentation and aggregation of homogenization.This is coincide the city’s human landscape changes interference theory.On the landscape patches level,the water,woodland and farm land are the main land use type in Zhuhai City.During the research time period,the cultivated area and beach area are significantly reduced,on the other hand,the water and building land area are substantial increase in 1999 to 2013.Patches increasingly squaring,landscape fragmentation intensifying,the degree of aggregation increasing,and connectivity declining.2.Urban ecological security status evaluation:based on the PSR ecological security evaluation model,several indexes are chosen to use in this system,such as the population density,landscape diversity and hydrological regulation.The result shows that in 1999-2005,2005-2009 and 2009-2013 these three time stages,the safety threshold scores of Zhuhai are 0.509,0.463 and 0.421,which are in alert status.Ecological safety status scores are continually reducing.This result shows that urban ecosystem of Zhuhai are facing a certain degree of structural changed,influenced by human activities heavily.Which means the situation approaching the ecological threshold.And the system is still in a stable,but sensitivity state.The ecosystem can be maintained,but has a small ecological anomalies approaching.The mainly as follows:area of natural wetland degradation,biodiversity worsen,landscape diversity loss,patch fragmentation serious,external system stress forced heavily,functional decline,wetlands and woodlands exploitation irrational,beach protection on a lower level.Thus factors affect the ecological health on both the process of ecosystems and the effect of human activity.3.Ecological security network pattern:Using the 2013 classified data set of Zhuhai,setting forest,wetland as ecological source,and the water body ecological sinks,the ecological security network can be formed.This network based on the the minimum distance theory and the ecological flow depletion theory.This research choose the minimum line as the ecological corridor.And with the help of the Arcmap,the ecological corridor network are formed and the ecological node are formed.Two different level of ecological corridor are qualitatively set.The result turns out that there are to levels of corridor and three levels of ecological nodes.All these ecological elements form into the ecological security network.According to the result the pattern of landscape security in Zhuhai,the south area and the west area of Zhuhai city is ecOlogical strongly connected,and the north area and the east area of Zhuhai city is ecological poorly connected.Because the main urban area is in the east area,and there is a river come through the city by the middle.Some area need to be change into more eco-friendly land use type.