Spatiotemporal Evolution And Regionalization Of Suaeda Salsa Wetland Degradation In Liaohe Estuary

Suaeda Heteroptera is an important ecological resource in Liaohe estuary.It plays an important role and far-reaching influence on enriching wetland environment,regulating regional climate,strengthening tourism value,and improving the quality of life of local people.In the past 30 years,Suaeda Heteroptera wetland in the estuary of Liaohe River has experienced several large attenuation and evolution,which has seriously affected the stability of the local wetland ecosystem.At the same time,the cliff type degradation of Suaeda Heteroptera wetland has also affected the development of local tourism The sustainable development of economy is of great significance.Taking the East Bank of liaohekou in Panjin City as the research area,taking the remote sensing images from 1988 to 2019 as the basic data,using the maximum likelihood method in envi5.3 software to identify and interpret the surface features in the study area,extract the information and distribution characteristics of the Liaohe estuary,analyze the spatial transformation relationship between Suaeda Heteroptera wetland and other ground features through transfer matrix,and analyze the pterygium alkaloid at the landscape level by fragstats4.2 Arcgis10.2 was used to divide the wetland grid and extract the information of Suaeda Heteroptera wetland area.The entropy method was used to calculate the degradation score and partition.Finally,the influencing mechanism of Suaeda Heteroptera wetland degradation in Liaohe estuary was analyzed from the aspects of natural factors and human factors.The conclusions are as follows:(1)From 1988 to 2019,this study divided the area change progress of Suaeda Heteroptera wetland in the East Bank of Liaohe estuary into six stages: small fluctuation stage(1988-1999),overall growth stage(2000-2001),rapid degradation stage(2002-2004),stable growth stage(2005-2014),comprehensive degradation stage(2015-2016)and small fluctuation stage(2017-2019))。 Among them,Suaeda Heteroptera wetland area reached the maximum value of 10.05 km2 in 2014 and the minimum value of 0.37 km2 in 1992.The degradation of Suaeda Heteroptera wetland is mainly distributed in the eastern boundary of the study area,near the artificial buildings;the growth of Suaeda Heteroptera wetland is mainly distributed in the western coastal area of the study area.(2)From 1988 to 2019,the net decreased area of Suaeda Heteroptera wetland was 40.46km2,and the net increased area was 40.65km2.Among them,the conversion of river beach,reed wetland and Suaeda Heteroptera wetland accounted for the largest proportion.The conversion area of reed wetland and mixed wetland into Suaeda Heteroptera wetland was 2.85 km2 and 3.32 km2,respectively.The conversion of river beach and artificial construction occupied Suaeda Heteroptera wetland area were 1.18 km2 and 4.81 km2,respectively.(3)According to the analysis of the growth and degradation situation of Suaeda Heteroptera in the study area in the past 30 years,the wetland of Suaeda Heteroptera can be divided into seven regions,which are high growth area,moderate growth area,low degree growth area,severe degradation area,moderate degradation area,low degree degradation area and no growth area.The total area of Suaeda Heteroptera wetland growth area is 14.05 km2,and the total area of degradation area is 6.81 km2.Data analysis shows that the growth areas of Suaeda Heteroptera wetland are mainly distributed in the coastal area of the study area,and interact with the river beach.The degradation area of Suaeda Heteroptera wetland is mainly distributed in the central and eastern boundary of the study area,and is seriously disturbed by artificial buildings.(4)Through the analysis of meteorological and soil natural factors,the overall correlation between the degradation of Suaeda Heteroptera wetland and meteorological factors(precipitation,temperature,sunshine hours)is not high,which indicates that meteorological factors are not the dominant factors of Suaeda Heteroptera wetland degradation.The results showed that p H value,alkali hydrolyzable nitrogen content,available potassium content and available phosphorus content of soil factors had no significant correlation with the area of Suaeda Heteroptera wetland,and had little impact on the degradation of Suaeda Heteroptera wetland.However,soil water content and salt content index had a greater correlation with the degradation of Suaeda Heteroptera wetland,which were the dominant factors for the degradation of Suaeda Heteroptera wetland.Human factors have a significant impact on the degradation of Suaeda Heteroptera wetland.Agricultural cultivated land reclamation and tourism construction and development directly lead to the reduction of Suaeda Heteroptera wetland area.The construction of dampproof dam,tourism facilities and reservoirs has changed the external environment of Suaeda Heteroptera wetland growth.Human factors have a significant correlation with the degradation of Suaeda Heteroptera wetland,and human factors are responsible for the degradation of Suaeda Heteroptera wetland area The main reason of the transformation.