Evaluation and optimization of woodland ecological patterns for Qingdao based on the agent based model
Urban socio economic development and urban spatial expansion has led to the loss and fragmentation of habitat.Global climate change adds to the gravity of these effects.The survival of wildlife species is subjected to enormous pressure due to natural environmental changes and human activities.Agent based models(ABMs) are computer simulation models analyzing and simulating human or animal behavior through the integration of learning,adaptation,evolution and logical analysis.ABMs study the overall system characteristics by analyzing internal elements of the system(such as the interaction among individual agents,and agents with the environment) with a bottom up approach.The agents in ABMs can complete given objectives,perceive and respond to changes of the external environment through the default logic control,and respond to stimuli from other agents and the external environment through learning and adaptation functions.This paper designed an agent based evaluation model of an ecological pattern,which was used to analyze the impact of different woodland patterns on species survival and dispersal.The model focused on the logic control of survival and dispersal of agents,and used the dispersal strategy integrating CRW and LW models,which combines the advantages of these two models.The survival of the agent is control by the age specified U shaped survival curve and determination function considering their own energy and environmental risks.The model was developed on the GIS platform,realizing the seamless integration of the agent model and GIS,which could then be applied to real geographical environment simulation.Qingdao is a city located in the eastern coastal region of China where the economy is relatively well developed.The region is also where marine and terrestrial ecosystems meet.Woodland is mainly distributed in the Laoshan Mountains in the east,the Daze Mountains in the north,and the Dazhu,Xiaozhu and Tiejue Mountains in the south.In the study area,the ecological environment is deteriorating,and various wildlife species are being impacted,with some species being endangered or facing extinction.This paper selected the woodlands in the Qingdao district as the study object,analyzing the effect of different spatial patterns on the survival and spread of woodland species.Simulation results showed that,compared with the original state,species populations and migration have improved significantly under different levels of ecological network framework,and the higher the level of ecological network framework,the more obvious the improvement.The distance between patches had a large influence on the dispersal of simulated species because they were not able to arrive at patches that were far away from the original patch.Therefore,this paper makes the suggestion that an approach integrating wetland and woodland systems could strengthen woodland system functional contact in the study area.It is suggested that the region around Jiaozhou Bay and the mainstream of Dagu River be used to increase the spatial distribution of woodland.Based on the simulation results,suggestions for the woodland ecological pattern construction are given below:(1) ensure that the large woodland can not be destroyed;(2) the wetland system district in the middle of Qingdao is an ideal place for a new woodland construction;(3) the ecological network framework can be used as a spatial reference for an ecological barrier to prevent the spread of urban land into woodland.