| As a part of the urban ecosystem,urban green space undertakes a variety of ecological service functions.Urbanization has destroyed urban habitats and led to a series of consequences including the reduction of biodiversity.The deteriorating urban environment requires new forms of green space planting to meet the challenges brought about by urbanization.Ecological planting Design is based on fully understanding the growth laws of natural plant communities,mainly selecting herbaceous plants,and using ecological methods(niche,plant functional traits,etc.)to configure plant communities with ecological service functions as the main function.Based on the assumption that the temporal and spatial changes of abandoned farming communities can provide referen ce for community structure and management methods for Ecological Planting Design in urban habitats with different moisture conditions,on May,July,September,and November 8-15,2020,systematic random sampling was used to investigate northeastern Jiangxi.There are36 sample plots in 12 plots including dry land and paddy field abandonment in the 1st,3rd,8th,and 15 th years without disturbance,moderate disturbance in the 15 th year,and severe disturbance in the 15 th year.Analyze the impact of community type structure,species diversity,community stability,community niche and disturbance on community changes,explore the structure design and management methods of urban ecological planting communities from the changing laws of abandoned farming communities,and provide a variety of ecological services for urban green spaces Features provide more possibilities.The results are as follows:(1)The change sequence of the community in 1-15 years of abandonment of dry land is annual plant community → perennial + annual plant community → perennial +shrub plant community.In the 8th year,shrubs begin to appear in herb communities with higher species diversity and stability,The proportion of high,medium and low plants stratification is 45%-47%-8%;it means that the more diverse the life form composition,the higher the diversity and stability of the community,but the middle-layer herb must occupy the largest proportion of the plant composition,and the growth of shrubs will reduce the species of the herb community Diversity.Ecological planting in the mesoenvironmental environment of cities with similar climates can be used for reference in the8 th year of dryland abandonment of perennial grasses + perennial non-grainaceous plants+ annual herbs + shrubs + vines.The community structure is mainly composed of midlevel plants.Ecological configuration Community.(2)The community change sequence of 1-15 years of abandoned paddy field is listed as annual plant community → perennial + annual plant community → clonal perennial plant community.The herb community that begins to appear in shrubs in the15 th year has higher species diversity and stability,high,medium and low hierarchical plants account for 60%-30%-10%.The ecological planting community of urban rainwater gardens with similar climate can learn from the 15 years of abandoning paddy fields.A variety of clonal multi-stem herb plants grow alternately from the group,and each group has its own different flowering season.The community structure of plants and lower-layer plants is mainly composed of middle-layer plants in the ecological community.(3)During the change process of the abandoned farming community in dry land and paddy fields,gramineous plants occupied the dominant species in dry land in t he first,third,eighth,and 15 years,respectively,and sub-dominant species 5/8,0/8,4/8,6/8 in paddy fields.Ratios of 4/8,3/8,3/8,2/8.Compositae are 2/8,1/8,0/8,0/8 in dry fields,2/8,5/8,1/8,and 0/8 in paddy fields;Gramineae and Compositae have influence on community changes and community appearance.Significant influence.Gramineae and Compositae are introduced and cultivated in cities with perfect technology.There are various types of flowering plants in each season,and they can be used in combination in the allocation of urban ecological planting species.(4)Seasonal stagnant water will slow down the rate of change of the community,allowing perennial herbaceous plants to occupy the dominant position of the community for a longer time,reducing the species abundance and species diversity of the community,but it will increase the number of community species and community stability.That is,sufficient water supply is conducive to the stability of the community,but it will also crowd out unsuitable species.The species and quantity of the artificially established communities change the fastest within 1-3 years,after which the communities tend to stabilize.It is recommended that after the ecological planting community is established for 3 years after the community is relatively stable,the fertility and water supply should be appropriately increased to improve the community’s anti-disturbance ability and community stability.(5)The comparative study on the 15 th year of dryland and paddy field communities of abandoned farming at the three levels of no disturbance,moderate disturbance and severe disturbance supports the hypothesis of moderate disturbance.Spring grazing or mowing is beneficial to increase the species diversity of the community.Corresponding to the ecological planting design of urban green space under different water conditions,suggestions for community configuration and management methods are provided for reference.Through the analysis and summary of the literature on ab andoned farming succession and ecological planting design,it is found that the application of this community structure is not limited to the northeastern Jiangxi region.The community structure composed mainly of middle-level herbaceous plants is conducive to the species diversity and stability of the ecological planting community.Large family species are relatively more applicable in ecological planting.Appropriate human disturbance is also conducive to maintaining the diversity and stability of the community. |
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