Dynamic Evaluation Of Gannan Regional Ecological Health Based On BPSR Model

For the purpose of ecological environment management,ecosystem health is a research hot spot in the field of ecology.That is a great meaning for evaluating the development of regional ecosystems,improving regional ecological environment and regional sustainable development.Dependent on the information technical support of GIS,RS and GPS,with reference to the PSR(Pressure-State-Response)model,the Basic condition-Pressure-State-Response(BPSR)model was rebuilt.Based on the four conditions as basic condition,pressure,state and response,25 evaluation indicators of natural environment and human activity were selected to be constructed Gannan Prefecture regional ecosystem health evaluation system.Meanwhile,the entropy method was used to calculate the weight of individual indicators,and combined with remote sensing and GIS technology,the dynamic assessment of Gannan regional ecosystem health status had been done from 2000 to 2015.So,the spatial and temporal distribution pattern and trend evolution of the regional ecosystem health had been shown in the main results as that:1)The BPSR model was rebuilt,and the basis condition of the existence and development of the ecosystem had been considered further.With this model,the spatial changes,Structural changes and external disturbances could been more comprehensively reflected.2)For the results of the index weight analysis of the entropy method,the sort from large to small values is as follows: the pressure indicators(0.3839),the response indicators(0.2753),the state indicators(0.2615),and the basic condition indicators(0.0793).3)Gannan regional ecosystem health value is in the range of 0.17-0.62,with that,the ecological health levels were divided as low health,lower health,moderate health,higher health and high health.4)From year 2000 to 2015,the regional ecosystem health level in Gannan shows a spatial distribution pattern decreasing from southwest to northeast.5)In the past 16 years,73.04% the grassland ecosystems were over the moderate health level,80.6% the forestland ecosystems were between the lower and the moderate health level,99.52% the urban-farm ecosystems were below the moderate health level,72.88% the terrestrial aquatic ecosystems were between the moderate with the high health level,and 52.54% of other ecosystems at the higher health level.6)Overall,the high and the low health levels area were decreased,and more area tended to change to the moderate health level.Meanwhile,the ecosystem health level was decreased in the southwestern region,and that was increased in the northeast and southwest regions of Ganna.