Study On The Evaluation Index System Of Ecological Degradation In Liaohe Estuary Wetland

Wetlands are one of the most important capital environments for humankind.Wetland ecosystems have a variety of functions and values,it plays an extremely important role in providing sources of water,regulating climate,promoting siltation,degrading environmental pollution,protecting biodiversity and maintaining regional ecological balance.With the development of human society,the degraded wetland ecosystem has caused changes in the ecological structure of wetlands and changes or partial loss of ecological functions,resulting in reduced wetland area,deterioration of water quality,and decline in biodiversity,threatening the sustainable development of the regional and global socio-economic environment.Caused widespread concern.Wetland research has gradually become a hot issue in the academic community.An in-depth study of the landscape change characteristics of the Liaohekou wetland is conducive to understanding the current situation of the Liaohe Estuary Wetlands,establishing a Liaohekou Wetland Degradation Assessment System,and defining the degree of degradation as a scientific basis for the sustainable development of wetland restoration and reconstruction,which has important theoretical and practical significance.In this paper,the Liaohekou Wetland was selected as the research object.At the same time,1985,1989,1995,2000,2005,2009 and 2015 were used for the simultaneous analysis of remote sensing images,meteorological and socio-economic data.The ArcGIS software was used to interpret the remote sensing image to acquire data and process it via Excel.Data,SPSS and grey correlation analysis data were used to determine the spatial-temporal characteristics of Liaohekou wetland landscape change,and on this basis,a degradation grade assessment for Liaohe Estuary wetland was established to determine the degradation status of wetlands at each stage and rank them.Conclusions are as follows:（1）Over the past 30 years,the Liaohe estuary wetland showed a state of gradual atrophy.The area of wetland was reduced from 1230.79km²in 1985 to 1150.83km2 in2015,which reduced a total of 79.96km².The annual average deceleration rate was about2.67km²,of which the total area of natural wetland was reduced by 281.76km²and the total area of artificial wetland increased by 201.80km².In the same period,the land use type of the Liaohe estuary wetland also changed obviously.In the dynamic change of Liaohe estuary wetland,the transformation of natural wetland to artificial wetland was 15.64%,and the loss of natural wetland and artificial wetland to non wetland wetland was 6.20%.The trend of Wetland Dynamic changes is obvious.Aquaculture farm,paddy field,oil field land,transportation land,construction land and pond reservoir are on the rise.The tidal flat and mixed wetland show a downward trend,which indicates that the utilization of human activities to wetland is gradually deepened.Although there is an upward trend in Suaeda wetland and river shallow sea area,the dynamics of reed wetland and canal ditches are decreasing.Due to the gradual maturity of human activities,the dynamics of constructed wetlands and non wetlands gradually diminished.（2）The degradation of Liaohe estuary wetland mainly consists of two aspects:natural factors and social factors.Human activities are the main factors leading to wetland degradation.The evolution of wetland ecosystem in a long time is mainly influenced by climatic factors.Human activities have a direct impact on Wetlands in a short period of time.The one or two and three industries will cause damage to wetlands in different degrees.The area of Liaohekou wetland is linearly related to various social and economic factors.Through a stepwise regression analysis of the natural wetlands and constructed wetlands of Liaohe River estuary and various socio-economic factors,a prediction model of wetland area change is established.The equation for calculating the area of natural wetlands is:(S_天然（28）1181.716-.363P（10）2.825T,R²=0.977).The equation for the constructed wetland area is(S_人工（28）50.377（10）.3993P-.3234T,R²=0.973).This paper makes a prediction model of wetland area change through the social and economic value,which is rare in the study of the influence of human activities on wetland.The results show that the error of the area prediction model is about 10%,which can be used to predict the wetland area.（3）Through data investigation and calculation,it is known that during the 30 years of1985²015,the wetland of Liaohe estuary showed a continuous degradation trend,and the degradation degree was grade III moderate degradation.According to the foundation of wetland evaluation at home and abroad,and the characteristics of ecological environment,a set of ecological degradation evaluation index system is established.Based on the evaluation basis of a large number of wetlands at home and abroad and the characteristics of the ecological environment of Liaohekou wetland,a set of ecological degradation evaluation index system for Liaohekou wetland was constructed,which was given weight by the method of Rough Set and AHP,and based on the comprehensive evaluation of wetland degradation index,based on the reference historical documentation and wetland ecological theory.Based on the AHP method,the evaluation index from the subjective judgement matrix is 0.4550（moderate degradation）,and the combined evaluation index of wetland degradation in Liaohe estuary is 0.4739（moderate degradation）,which shows that this study can more accurately judge the trend of wetland degradation in Liaohe estuary.