Analysis Of Temporal And Spatial Heterogeneity And Driving Factors Of Ecological Environment Quality In Plateau Lake Basins Based On RSE

Fuxian Lake and Xingyun Lake are typical plateau lakes,characterized by poor self-purification ability and fragile ecosystems,and the lakes are surrounded by mountains,forming a more closed lake basin ecosystem.The deterioration of the watershed ecological environment will destroy the stability and balance of the watershed ecosystem,thus affecting the regional natural ecological resources and ecosystem service functions.Timely and scientific ecological monitoring and evaluation of the watershed can provide a theoretical basis for ecological and environmental management of the two lakes basins,facilitate decision makers to grasp the overall environmental situation of the basin,target the existing environmental problems for management,more conducive to the sustainable development of regional nature and economy,and can provide a theoretical basis for the evaluation of ecological and environmental quality of the highland lake basins.In this paper,Fuxian Lake and Xingyun Lake basin were selected as the study area,based on Landsat 5 TM/8 OLI data for 5 periods in 2005,2009,2014,2018 and 2021.By inverting greenness,humidity,dryness,and heat indicators,principal component analysis is used to construct the RSEI model.Based on the RSEI model,the ecological and environmental quality of Fuxian Lake and Xingyun Lake watersheds were monitored and evaluated from 2005 to 2021,and their spatial and temporal changes were quantitatively analyzed.And the spatial clustering characteristics and changing trends of RSEI were analyzed using global and local spatial autocorrelation techniques.In addition,the driving mechanisms of the ecological and environmental quality changes in the study area in 2009,2014,and 2018 were analyzed based on the geographical detectors model,and the land use changes in the study area and their ecological and environmental effects were analyzed in depth.The following main conclusions were drawn:(1)The average value of RSEI in Fuxian Lake and Xingyun Lake basin from 2005 to 2021 is stable at about 0.5,and the ecological environment quality is at a medium level(0.4-0.6),and the overall trend of ecological environment quality tends to decline.With the development of cities,the ecological and environmental quality of Fuxian Lake and Xingyun Lake basin along the lake flat area town gathering area gradually becomes worse.The development of phosphorus chemical and quarry industries and the existence of historical legacy mines in the hilly areas to the northeast of the Fuxian Lake basin and to the southeast of the Xingyun Lake basin have led to insignificant changes in RSEI and poor ecological environment quality during the study period;the ecological environment quality has been very poor during the study period because of the typical karst landscape and the incompatible human-land relationship leading to more serious stone desertification in the mountains in the southwest direction of Fuxian Lake basin;the ecological environment quality of the mountains in the other directions of the study area has improved significantly.(2)Moran’s I index was positive from 2005 to 2021 in the Fuxian Lake basin,and all of them were less than 0.35,with a weak positive correlation of ecological and environmental quality,while Moran’s I value gradually increased after 2014,and the correlation gradually enhanced.The Moran’s I index in the Xingyun Lake basin from2005 to 2021 was also positive,and all of them were greater than 4.5,with a medium level of positive correlation in ecological environmental quality,while the Moran’s I value tended to decrease during the study period,and the spatial aggregation characteristics of ecological environmental quality gradually weakened.The changes in the spatial aggregation patterns of Fuxian Lake and Xingyun Lake watersheds are consistent with the trend of changes in the spatial distribution of ecological environmental quality,which is closely related to the implementation of national policies and the development of cities.(3)The driving mechanism of ecological and environmental quality changes in the study area from 2009-2018 was analyzed using the geographical detectors model.The main factor affecting the spatial differentiation of ecological and environmental quality in Fuxian Lake and Xingyun Lake watershed is the type of land use,and the distance from the watershed has the least influence on it.The impact of interactions between factors on the change of ecological environmental quality in the study area is higher than the original impact produced by different factors alone,and is more likely to promote the change of ecological environmental quality.Among them,the interaction between land use type and other factors is the strongest in 2009,2018 and 2021.(4)The changes in ecological and environmental quality of Fuxian Lake and Xingyun Lake basin from 2009 to 2018 are closely related to the changes in land use types.The land use types in the study area are mainly arable land,forest land and water area,and the land use changes are characterized by the encroachment of construction land into other land use types,with the major inflow land types of construction land being arable land and forest land.The unreasonable land use pattern in the study area has reduced the land carrying capacity and led to the degradation of ecological environment quality along the lake flat area.From 2005 to the present,the area of construction land in Fuxian Lake and Xingyun Lake basin has steadily increased,but the increased construction area during 2019-2022 is outside the primary protection zone of Fuxian Lake and Xingyun Lake basin,which shows that the protection regulations implemented for Fuxian Lake and Xingyun Lake basin have been strictly enforced.Moreover,due to the high water and fertilizer consumption planting structure of the arable land in the Xingyun Lake basin,which leads to a large amount of nitrogen and phosphorus nutrients entering Xingyun Lake,agricultural surface source pollution has become one of the main reason for the deterioration of water quality in Xingyun Lake,and is also one of the main reason for the difference in water quality between Fuxian Lake and Xingyun Lake.Reasonable planning of land use structure is the key to achieve a balance between regional economic development and environmental protection.