| Coastal zones connect the sea to the land and are home to 60%of the world's population[1].The dense population and high-intensity production activities have greatly changed the land use mode in coastal zone,and the vulnerable ecological environment in coastal zone is also threatened.In the past 30 years,human industry,agriculture and life have caused changes in land use patterns and landscape patterns[2].With the rapid development of economy in China's coastal zone,the response relationship between human activities and landscape pattern in coastal areas provides an important theoretical reference for regional rational planning and landscape ecological security[3].To find the interrelationship between the intensity of human activities and the landscape,accurately assess and monitor the spatial and temporal layout and changes of human activities,develop and restore ecological security network,all of these can provide reference for the correct layout of landscape space and alleviate the antagonistic relationship between human activities and ecological balance.In this paper,we choose the land use data of Yueqing Bay in Zhejiang Province in1995,2000,2010 and 2015,to analyzed the spatial and temporal distribution characteristics and changes of various landscapes in Yueqing Bay in recent 20 years.Based on the normalized area-weighted formula and the gravity center model,the dynamic characteristics of human disturbance intensity in Yueqing Bay were revealed,and the spatial correlation between human disturbance intensity and landscape pattern was explored.The landscape change intensity model of Yueqing Bay was constructed based on the intensity of human disturbance,so as to reveal the landscape ecological security problems in Yueqing Bay.At the same time,according to the selection of ecological sources and ecological corridors,the ecological security network of Yueqing Bay was constructed,and corresponding optimization countermeasures were put forward in view of the actual ecological security problems in Yueqing Bay.The main findings are as follows:(1)The landscape index of Yueqing Bay shows different grain size effects with the change of grain size.The response of cultivated land,forest land and beach landscape to grain size is obvious.Landscape granularity effect is divided into four types at landscape level:The first type of landscape index showed an increasing trend with the increase of grain size(AREA-MN?PAFRAC);the second type of landscape index decreases with the increase of grain size(ED?LSI?AI?FRAC-MN?CONTAG);the third type of landscape grain size curve changes in complex,no obvious rule(DIVISION?LPI);the landscape index of the fourth type changed almost no change with the change of grain size(SHDI?IJI).The inflection point of landscape granularity appears within 60-100m.According to the precision loss index of land area,the larger the selected grain size is,the greater the precision loss of land area is.The range of60m-100m is the most suitable granularity for the landscape study of Yueqing Bay,and60m is the best scale for the landscape study of Yueqing Bay.(2)The spatial distribution of landscape pattern and human disturbance intensity in Yueqing Bay changed from 1995 to 2015.According to the correlation analysis,Choose LPI?LSI?AREA-MN?IJI?DIVISION and SHDI to study the landscape pattern of Yueqing Bay.In the past 20 years,the area of woodland and cultivated land has been greatly reduced,the area of urban land and building land has rapidly gathered and expanded,and the area of water and tidal flat has changed little.At the landscape level,the ratio of the largest patch to landscape area increased,and the diversity of landscape increased.Human activities first broke the woodland,grassland and other large landscapes,resulting in landscape fragmentation and complex shapes.Then,human activities have intensified,and the area of man-made landscape has been centrally distributed and gradually expanded.From 2010 to 2015,the shape of land patches in Yueqing Bay tended to be regular,and the landscape integrity improved.(3)From 1995 to 2015,the intensity of human disturbance in Yueqing Bay increased,and the four phases were dominated by medium to low disturbance and low disturbance.The area of medium to high disturbance and high disturbance increased continuously,especially in Hongqiao Town,Lecheng Town,Zhugang town and Chumen Town,where the area of medium and high disturbance and high disturbance was concentrated,and the center of human disturbance intensity gradually shifted to the southeast of Yueqing Bay.The intensity of landscape change shows that the overall landscape ecology of Yueqing Bay is gradually deteriorating,the natural landscape is transformed into artificial landscape,and the ecological risk is increased.Among them,Zhugang Town,Chumen Town,Haishan Township and other places had a serious deterioration of landscape ecology.Because of the high intensity of human activities in the early stage,the intensity of landscape change in Lecheng Town and Hongqiao Town was slightly lower,but they were also in the condition of ecological deterioration.Combined with the topographic map,the ecological deterioration area of Yueqing Bay is concentrated in the valley areas on the north and northeast sides,which are ecological protection areas.But in these years,human activities are developed vigorously.(4)In this paper,the ecological security network of Yueqing Bay is constructed through the ecological source corridor node system.There are 14 ecological source areas with a total area of 460.624 km2 in Yueqing Bay Area based on the particle size back inference method,a total of 27 ecological corridors in Yueqing Bay were identified based on the Minimum Cumulative Resistance model,the total length of the ecological corridor is 851.43km,and there are 32 important ecological nodes.The spatial layout of Yueqing Bay ecological network needs to be reasonably planned.In the northeast of Yueqing Bay,due to the relatively intensive human activities in the valley area,the natural ecological corridor is cut off and the ecological source area is fragmented.The ecological network is sparse and the ecological corridor is long in the West and Southeast.The ecological network was evaluated by landscape integrity index,and it was found that the ecological network in Yueqing Bay area had low integrity,was easily disturbed by human activities,and had poor stability The study found that we can take method by increasing the number of ecological sources,Protect the ecological balance of ecological source and dredge the high resistance of ecological corridor,and appropriately increasing the number of stepping stones in the western and southeastern regions. |
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