Evolution Of The Landscape Pattern Of The Wuyuer River Basin And Its Ecological Quality Evaluation

With the accelerated urbanization and rapid economic development of the Wuyuer River Basin,human activities have had a major impact on the ecological environment and ecological landscape of the Wuyuer River Basin.Excessive human interference has directly or indirectly had a negative impact on the watershed's ecosystem,and these negative impacts have led to dramatic changes in the landscape pattern,impacting on the normal functioning of the ecosystem and ultimately leading to a reduction in ecological quality.In this paper,the Wuyuer River Basin is taken as the study area,and the Landsat series images of 1980,1995,2000,2010 and 2020 are used as the basic data support.The ENVI5.3 platform is used to standardize the remote sensing images,and the spatiotemporal correlation rules,landscape transfer network and PLUS model are used to analyze the landscape pattern change characteristics and evolution patterns of the study area.The RBF neural network model was also applied to evaluate and grade the ecological quality of the watershed and reveal its ecological quality change trend.The main findings are as follows:(1)Based on WEKA data mining platform and using FP-growth algorithm to mine the evolution trajectory and change characteristics of Wuyuer River Basin landscape,it is found that the final results of landscape evolution trajectory of Wuyuer River Basin mostly point to cultivated land,indicating the increase of cultivated land area.The main reason is that the Wuyuer River Basin is located in the Songnen Plain,which is the main food-producing area in the northeast,and requires large-scale cultivation of arable land to grow crops due to policies,economic development and population increase.The increase in arable land is mainly concentrated in the pre-mountain plains,low hills and river valley zones in the northeastern source area of the wuyuer river and the downstream area of the wuyuer river before it enters the Zhalong Wetland.The increased arable land area in the source area is formed by the conversion of forest land,and the arable land area in the downstream area is formed by the conversion of grassland and swampy wetland.(2)Analyzing the direction of mutual transformation among landscape types and the active degree of landscape with the help of Ucinet 6.0 software,it was concluded that the transfer relationship among all landscape types in the Wuyuer River Basin has occurred in the past 40 years.Among the many landscape transfer relationships,the transfer between three landscape types,namely,arable land,grassland and swampy wetland,is dominant,while the transfer intensity of residential land is the lowest and the degree of activity is the lowest.(3)The results of the simulation accuracy show that the use of the PLUS model to simulate the landscape change and spatial pattern of the Wuyuer River Basin is very reliable.The analysis of landscape expansion strategies using the PLUS model shows that GDP,elevation,distance from highways,distance from rivers and distance from cities have a significant effect on landscape change.Using the PLUS model to predict the spatial distribution pattern of the landscape in the Wuyuer River Basin in 2030,the results show that: the area of arable land in the Wuyuer River Basin increases the most,followed by residential land,and swampy wetlands and water bodies also show a small increase in area.The area of woodland,grassland and unused land decreased.The overall trend is for forest land,grassland and unused land to be converted into arable land and residential land.(4)Sixteen indicators were selected to construct the evaluation index system of landscape ecological quality of Wuyuer River Basin from three aspects: landscape stability,landscape disturbance degree and socio-economic impact degree,and the ecological quality value of Wuyuer River Basin was obtained by applying the RBF radial basis function neural network model.The ecological quality of the Wuyuer River Basin was found to be between excellent and average,but gradually approaching to average,reflecting the trend of degradation of the ecological quality of the Wuyuer River Basin in the bad direction.The ecological quality condition of the Wuyuer River Basin did not show a huge decline,mainly because the per capita GDP increased more than 70 times,as well as the maximum patch index increased 1.6 times,which played a certain inhibiting effect on the decline of the ecological quality of the basin.The 1.3times increase in the landscape variability coefficient has contributed to the decline in ecological quality of the basin.