Study On Spatiotemporal Changes And Influencing Factors Of Ponds In Min Delta Region

The ecological and environmental quality level of the Min Delta region has always been at the forefront of our country.However,with the rapid urbanization of the region,the land-use type changes caused by social and economic development,and the large increase in population density has made research on how to use and protect water resources efficiently.Excessive exploitation of water resources,reclamation of wetlands,land reclamation,urbanization expansion,and increase in construction land have severely damaged wetland ecosystems.ponds,as a type of wetland,are also a small class closely related to residents’lives.Analyzing the temporal and spatial changes of water bodies and exploring the response mechanism of natural and human activities to the changes of and ponds are of great significance for promoting the scientific management and planning of water resources in the Min Delta region,and the sustainable using of ponds.In this study,using multi-source remote sensing images of SPOT-5,ZY-3 and GF-1 and using an object-oriented decision tree CART classification algorithm to extract information based on the characteristics of the feature types of land classification system,and obtain the Pond spatial database and other land-use types in 2005,2010,2015,and2018.Additionally,describing and exploring the characteristics of pits and ponds in the four periods of the Min Delta region from the temporal dynamic change,spatial distribution,spatial dynamic change,land-use type transformation and spatial pattern of pond.It was found that the area of ponds in the Min Delta region decreased during the period of 2005-2015.Although the area of ponds increased during the period of 2015-2018,the area of ponds in 2018 continued to shrink compared to 2005.The total area decreased by 16.62km~2,a reduction of 8.73%.From the perspective of spatial distribution,ponds are mainly distributed in the eastern area of the Min Delta,and are relatively scattered in other areas.In addition,the changes between ponds and other land-use types are more complicated.The area transferred from ponds to other land-use types is significantly greater than the area transferred from other land use types to ponds.Due to the relatively complicated terrain and high elevation differences in the Min Delta region,the study found that the ponds are mainly located in the area with an altitude of 3-300m,and 3-150m is the main spatial distribution range of the ponds.The area of ponds at different altitudes is quite different,and the area of ponds on the whole showed an increasing trend with increasing altitude.This study found that ponds in the Min Delta region are concentrated in the eastern region and scattered in other regions.From 2005 to 2018,the area of ponds showed a trend of first decrease and then increase,but it was still shrinking as a whole.The analysis of the factors affecting the spatiotemporal evolution of ponds in the Min Delta region in 2005 and 2018 from the aspects of natural factors and human activities,respectively,found that the average annual temperature and topographical factors(elevation and slope)have a greater impact on them.The socio-economic development factors(GDP and POP)relatively have smaller affection.In addition,the annual average precipitation has significant differences with the effects of annual temperature,elevation,and slope on the spatial differentiation of ponds in 2005,but there is no significant difference in the effects of spatial differences in ponds in 2018.Furthermore,the study also found that when the meteorological factors interact with land-use types caused by human activities,the spatial differentiation of pond areas is significantly enhanced,which indicates that the combined effect of natural factors and human interference will increase the effects of spatial separation of ponds.This study has certain practical significance and provides a theoretical basis for the management of ponds in the Min Delta region and the utilization of pond water resources in this region by combining the temporal and spatial changes of ponds.