| The raised field agroforestry wetland is a kind of regional characteristic wetland morphology,which integrates the traditional farming wisdom and ecological practice of Lingnan area.Historically,the raised field agroforestry wetland was mainly distributed in the river area of the Pearl River Delta.There is a typical case of this type of wetland in Guangzhou Haizhu National Wetland Park,which is located in the central city of Guangzhou.Driven by the background of urban ecological civilization construction,the government and relevant institutions have made clear the goal of collaborative restoration of fruit forest conservation and wetland ecological diversity in raised field agroforestry wetland.However,most of the current restoration plans focus on the guidance of technical strategies,and less on the guidance and control of site scale,which easily leads to the imbalance of the degree of artificial intervention.In recent years,Haizhu wetland has explored a variety of ways of ecological restoration practice,and the change of wetland morphology and structure is very significant,but there is no feedback evaluation mechanism after the transformation.Microclimate is a sensitive environmental variable to the change of site morphology,and has a great impact on the original fruit forest and other vegetation restoration.It can be used as one of the entry points of the evaluation feedback system after the transformation.Therefore,taking Guangzhou Haizhu National Wetland Park Phase II as an example,this study aims to compare and analyze the impact of site characteristics change on microclimate under different restoration modes,quantitatively analyze the impact mechanism,and on this basis,promote the site morphology design guidelines and scale control range of relevant indicators based on the healthy microclimate effect of fruit forest.The main contents of this paper are as follows(1)Theory and background data research: on the one hand,collect and collate the related literature of microclimate research,and clarify the research methods of this paper.On the other hand,combing the basic information of the raised field agroforestry wetland,combining with the relevant planning documents and the site evolution,the site type zoning of the raised field agroforestry wetland in the second phase of Haizhu wetland is carried out,and the "Restoration type" and "Remodeling type" sites are defined as the research objects of this paper.(2)Site characteristics carding and microclimate measurement: on the one hand,based on the relevant theoretical research and decomposition and reconstruction of site elements,the site characteristics of raised field agroforestry wetland were described from two aspects of element morphological characteristics and layout morphological characteristics.Then,the research sample plots were selected to collect the site characteristic data,and the qualitative and quantitative methods were used to sort out the site characteristics,and the differences between the two types of sites were compared.On the other hand,the microclimate data,including air temperature and humidity,soil temperature and humidity,were collected by arranging measuring points in the study plot to analyze the spatial and temporal distribution characteristics of microclimate in different types of sites and compare their differences.The results show that the microclimate effects of different sites are different,and the daily dynamic changes of air humidity and soil humidity in "Restoration type" and "Remolding type" sites are extremely significant,showing irregular fluctuations,and the variation curve has no obvious peak valley,and the maximum daily mean humidity difference of each site is 7.3% and 26.0% respectively;The daily dynamic trend of air temperature and soil temperature is similar,showing a single peak curve.The maximum daily mean temperature difference of each measuring point can reach 1.7 ?.The difference of microclimate effect between site units is confirmed,which lays the data foundation of impact effect analysis.(3)Analysis on the influence mechanism of site characteristics on microclimate and site optimization guidance: on the one hand,through the SPSS data analysis platform,the site characteristic factors with significant correlation with microclimate elements are screened,and on this basis,the influence mechanism of characteristic factors on microclimate elements is elaborated based on regression curve estimation,and the influence degree is compared according to the standardized coefficient,and the discussion is combined with the fitting curve The main influence range.The results showed that the change of site characteristics mainly affected soil moisture and air humidity,followed by air temperature,and had little effect on soil temperature.The main influencing factors of air temperature and humidity and soil humidity in "restoration type" and "remolding type" sites are channel width,water surface rate,water base ratio and channel width,channel density and pile foundation shape index,respectively,and have a certain influence range.On the other hand,combined with the influence object,degree and interval,the difference of influence mechanism between the two types of sites is compared,and combined with the recovery demand,the optimization design index and the scale control range of relevant indexes are proposed from four aspects of water-based proportion,water-based layout,canal width and pile foundation form.,Supplement and optimize the scale guidance part of the existing restoration regulations for the restoration strategy of morphological structures,As a case study,this paper defines the main site characteristic factors that affect the microclimate of raised field agroforestry wetland,and expounds its influence mechanism,which has a substantial guiding significance for site shape design in wetland restoration practice,and also provides an important theoretical basis and reference value for other similar wetland shape restoration. |
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