| Wetland system has the reputation of "the kidney of the earth".It has the ecological functions of protecting and purifying water quality,preventing drought and flood,regulating wetland climate and maintaining ecosystem diversity and stability.This paper explores the spatial and temporal variation characteristics of wetland environmental quality factors,wetland landscape pattern,and ecosystem suitability.On the basis of this study,the premise is to protect the landscape characteristics and resources of Guanzhuang Lake Wetland Park,and to provide scientific strategies for the sustainable utilization of Guanzhuang Lake Wetland Park,so as to ensure the win-win situation of the real sustainable development of cities and wetlands.The main results are as follows:(1)Spatial and temporal variation characteristics of water environment elementsMonitoring the water quality environment during dry season,flood season and normal season in 2018 shows that the average contents of metal elements Cu and Zn in wetland parks are 0.004 mg/L and 0.007 mg/L,which meet the requirements of Class I Water Standard of National Surface Water Environmental Quality Standard(GB 3838-2002).The contents of Pb,Cd and Hg contaminated elements in water environment were lower than the detection limit and could not be detected.The average pH value of water environment is 7.49,in which the total nitrogen and phosphorus content of Guanzhuang town is 5.36 mg/L and 0.244 mg/L in dry season seriously exceed the standard.The total phosphorus and nitrogen content of water environment in the middle tributary is 2.242 mg/L and 0.059 mg/L,which also exceed the requirements of Class ? water standard of National Surface Water Environmental Quality Standard(GB 3838-2002).In dry season,the inflow and flow rate of reservoir decreased,the water quality renewed slowly,the sediment of suspended matter increased,the dilution effect on the reservoir water was reduced,the water temperature was reduced,the biological activity of microorganisms,phytoplankton and plants in the water was affected,and the decomposition effect of biological action on nitrogen was reduced.A large number of fish excreta affected the water quality in the process of aquaculture in the reservoir area.The main sources of pollution are mainly from residential agglomeration sites in the region,which are highly disturbed by human activities.(2)Spatial Change Characteristics of Soil EnvironmentWetland soil pH ranged from 4.35 to 5.06,which was acidic and increased with the increase of soil layer.The spatial distribution of organic carbon,total nitrogen and total phosphorus in 0-20 cm soil of Wetland Park is obvious.Organic carbon:reservoir head(0.215%)>Guanzhuang town(0.184%)>wetland landscape(0.175%)>Natural Forest(0.120%)is due to the concentration of residual roots of many underground plants in Kutou and Guanzhuang town,which is rich in C source and relatively high in content.The soil environment of natural forest sampling sites is poor and the surface vegetation is less,so the input of organic matter is less and the content of organic carbon is less.Total phosphorus:Kutou(2.345 mg/kg)>Guanzhuang Town(2.034 mg/kg)>Wetland Landscape Area(1.536 mg/kg)>Natural Forest(0.792 mg/kg).Total nitrogen:Guanzhuang town(1.982 mg/kg)>Kutou(1.918 mg/kg)>wetland landscape area(1.484 mg/kg)>Natural Forest(1.302 mg/kg).The results showed that the decomposition of organic carbon in soil could promote the release of nitrogen and phosphorus to soil,and on the contrary,the increase of nitrogen and phosphorus in soil could also promote the accumulation of organic carbon in soil.Organic carbon content was positively correlated with total phosphorus and nitrogen content(P<0.01).The average value of Cd in the surface soil of Wetland Park is 0.6056 mg/kg,which is three times higher than the grade ? standard of the National Standard for Soil Environmental Quality.With the deepening of the soil layer,the accumulation of Cd increases.It may be that the vegetation adsorbs some Cd elements in the surface soil.The distribution of Pb content is uneven in the region,and the measured values vary greatly,ranging from 22.579 to 39.497 mg/kg.Among them,the content of Pb in Guanzhuang Town is 1.11 times higher than the first grade standard of the National Standard for Soil Environmental Quality.With the increase of soil layer,the content of Pb decreases,indicating that human disturbance is more serious.The average values of copper and zinc in surface soils were 23.66 mg/kg and 75.96 mg/kg,respectively,which did not exceed the grade I standard of the National Standard for Soil Environmental Quality.However,the overall contents of copper and zinc in Guanzhuang Town were relatively high,the pollution was serious and there was accumulation phenomenon.(3)Study on the Characteristics of Landscape PatternsFragstata 4.2 was used to calculate the landscape pattern index of GuanzhuangLake Wetland Park.The total area(TA)of Guanzhuang Lake Wetland Park was 1468.51 hm2.The total number of patches was 377,the average area of patches was 3.8953 hm2,the patch density(PD)was 25.6723/100 hm2,and the maximum patch area index(LPI)was 42.2823%.Landscape Shape Index(LSI)was 13.4781,in which the dominant patches of wetland park landscape were water and woodland,and human disturbance was weak.Landscape richness index(PRD)is 0.4086/100hm2,which indicates that the number of landscape elements in wetland parks is small,and the distribution is unbalanced,and the spatial heterogeneity of landscape is poor,which leads to weak omamentality,simple ecosystem spatial level,and ecological diversity is easily controlled and restricted by the waters in wetland parks.It is difficult to maintain a high number of species,rare species and endangered species.(4)Suitability analysis of wetland park ecosystemReferring to the National Wetland Park Assessment Criteria(LY/T 1755-2008),this paper uses the analytic hierarchy process to select the typical,unique,species diversity,proportion of wetland area,wetland water resources and other factors in the wetland park for gradual assessment,and obtains 68.6 points of Wetland Park ecosystem,which is summarized as "excellent".(5)Sustainable Utilization Strategy of Wetland Park LandscapeBased on the analysis of landscape pattern characteristics,spatial and temporal variation characteristics of wetland ecological environment factors and ecological suitability,the wetland park is divided into five functional zones:conservation zone,restoration and reconstruction zone,propaganda and education exhibition zone,rational utilization zone and management service zone,which highlight the integrity,functionality and species diversity of wetland ecosystem,forest belt,single tree and other forests.Components together constitute a landscape pattern connected by patches,belts and networks. |
PDF Full Text Request