The Theoretical Model And Forewarning Evaluation Of Land Ecosystem Health In Poyang Lake Eco-economic Zone

The sustainable and stable development of a region depends largely on the healthy status of land ecosystem.However,as a natural environment social economic complex system,the land ecosystem has the characteristics of openness,dynamic and hierarchy.These characteristics determine the uncertainty of the health warning.Human destruction of land ecosystem led to the changes or degradation of land ecosystem,and the changes or degradation of land ecosystem is often lagging behind the human action.Therefore,health warning must be made timely before the degradation of the land ecosystem.Otherwise,when the degradation reaches to a certain degree,the land can not be reversed any more.Therefore,exploring the health warning of the land ecosystem is extremely important and urgent.This paper,taking Poyang Lake eco-economic zone as an example,based on the perspective of hidden danger,constructs the theoretical model of evolution of the land ecosystem health to explore the evolution mechanism of the land ecosystem health under the common action of the hidden trigger transfer mechanism and the hidden danger control response mechanism.Then,based on the mechanism of the evolution of land ecosystem health,the theoretical framework of PSR model was established.Combined with the variation coefficient method and entropy weight method,the early warning index system is constructed from the hidden layer,status layer,response layer.The paper identifies the matter element model to evaluate the early healthy warning of the land ecosystem.Finally,according to the criterion of the health warning degree,the health of the land ecosystem of the study area was evaluated from the time scale and spatial scale.The results show that:(1)In the initial moment of the impact of health risks,the risk of the land ecosystem showing no trigger or trigger.When the hidden dangers are triggered,the hidden danger is transmitted and produced.When the force response mechanism of land ecosystem is strong,the land ecosystem will show a state of health or more health.When the force response mechanism of land ecosystem is weak,the land ecosystem will show a state of alert,medium warning even serious warning.(2)From the time scale,the health alert of Poyang Lake eco-economic zone converts from the healthier to the alert,then to the healthier,and the year of 2005 is a turning point of the health status.(3)From the spatial scale,11 evaluation unit land ecosystem health warning degree in the study area is between the warning alarm and middle warning alarm degree,indicating that the land ecosystem health has been subject to threats,which blocks the sustainable development of economy.The evaluation unit,combining with their own actual situation,should take positive corresponding measures to reduce the health warning degree.