Study On The Characteristics Of Arthropod Community On The Surface Of Natural Restoration Wetland In The Lower Reaches Of Tumen River

As one of the most important types of landscapes on the earth,wetlands have extremely important ecosystem service functions.However,due to changes in the natural environment and the intensification of human interference,wetland degradation and loss are very serious.Wetland ecosystems are severely affected and their ecological functions are impaired.They cannot fully realize their potential.At the same time,as the area decreases,the wetland ecological and economic benefits weaken.The biodiversity function is reduced and gradually lost.Since the 1990s,the shrinkage of wetlands has attracted the common attention of experts and scholars at home and abroad.Nowadays,humans do not understand the process of self-recovery of wetlands.Wetlands are still the most threatened ecosystems,which seriously hinders humans'wetland ecosystems.Scientific protection and repair process.In this study,the lower Tumen River,which is rich in wetland resources,was selected as the research area.Based on the observation of remote sensing image data over the years combined with field survey,three groups of wetland plots with different natural restoration years after paddy field abandoned farming and paddy fields were selected.2 groups of natural meadow swamp wetland plots.In the six months from May to October 2019,collect surface arthropods,survey vegetation and soil during the period of vigorous vegetation growth,count the number and number of groups,calculate the diversity index,and clarify various types of wetland arthropod communities Structural characteristics,through the response of the physical and chemical properties of vegetation and soil factors to the arthropod community structure,revealed the reasons for the differences in arthropod community structure at different stages of wetland restoration.The main findings of this study are as follows:(1)Sampling collected 25 orders of 109 families of surface arthropods,a total of 20798 animals.Among them,the largest number of individuals is Hymenoptera of Insecta,accounting for 43.99%of the total,mainly formicidae,followed by the Collembola of the Collembola,accounting for 33.49%of the total,and the order of Arachnida is 5.58%,Coleoptera of Insecta accounted for 4.21%of the total;the highest number of arthropod taxa collected was Arachnida(27 families),accounting for 24.77%,followed by Coleoptera 19 families,diptera There are 16 families in the order;the arthropods appearing in all plots are arachnids,coleoptera,cilioptera,diptera,hemiptera,hymenoptera,etc.(2)There are certain rules for the types and numbers of arthropods in different restoration stages of wetlands.There were 1881 arthropods collected in ordinary paddy fields and 47 families,and 2058 and 50 families were collected in organic paddy fields.The types and numbers of arthropods in organic paddy fields were higher than those in ordinary paddy fields.Wetland restoration for 5 years>Wetland restoration for 15 years>Wetland restoration for 30 years;Compared with ordinary paddy fields and wetlands with different restoration years,natural meadow swamp wetlands have more arthropods in common paddy fields than natural wetlands.The types and numbers of arthropods in wetlands are lower than the average value of natural wetlands;in the process of returning paddy fields to natural wetlands,the number and types of arthropods show a tendency to increase rapidly and then gradually decrease and stabilize.(3)Arthropods collected in different months have obvious seasonal changes in species composition,number of individuals,and number of groups.In terms of the number of arthropods,July is the highest,and the lowest occurs in October.From July to October,the number of individuals shows a gradual decrease.In terms of arthropod species,the number of arthropod groups collected is the largest in May,and the lowest is In August,the total decreased first and then increased;in terms of species composition,some arthropods did not appear in other months.Among them,the arthropods that survived only in September or before September,there are Dalidae,Coccinellidae,and Perchidae,8 families,16 families such as dragon lice,dragonfly.(4)The similarity between the restoration of the 5-year wetland and the 15-year wetland,the 30-year wetland and the natural wetland vegetation is high,the soil pH,the ratio of nitrogen and phosphorus decrease,and the soil organic matter and total phosphorus increase.With the increase of wetland restoration years,plant diversity gradually decreases,and the proportion of wet vegetation from low to high is 15 years of wetland restoration<5 years of wetland<natural wetland<30 years of wetland restoration,5 years of wetland restoration and 15 years of wetland restoration The similarity between wetland and natural wetland vegetation in the restored 30-year period is as high as 49%.Due to the reduction of human interference and the impact of precipitation,the soil bulk density decreases and the water content increases.The organic matter content and total phosphorus in the soil gradually increase.Redundancy analysis shows that the vegetation types in the restored wetlands are significantly related to the soil nitrogen-to-phosphorus ratio and vegetation carbon-to-nitrogen ratio(P<0.01).Xerophytic vegetation is positively related to soil nitrogen-to-phosphorus ratio,and negatively related to vegetation carbon-to-nitrogen ratio.Vegetation is the opposite;in addition,the types of vegetation in restored wetlands are correlated with surface biomass(P<0.05),and wet vegetation is positively correlated with surface biomass.(5)After analysis,the soil nitrogen to phosphorus ratio has a significant effect on arthropod diversity.CCA analysis of soil factors and diversity of arthropods in restored wetlands.The nitrogen-to-phosphorus ratio,total phosphorus,nitrogen-to-phosphorus ratio,pH,and water content of soil factors can explain 99.7%of arthropods in restored wetlands.Monte Carlo replacement Tests showed that the soil nitrogen-to-phosphorus ratio was significantly correlated with wetland arthropods(F=29.9,P=0.01),and that the soil nitrogen-to-phosphorus ratio was positively correlated with species richness index,and negatively correlated with diversity index,evenness index,and ecological dominance.