Ecological Protection Effect Of Urban Green Space Fencing In Nanchang

As an important part of the urban ecosystem,urban green space plays an important role in maintaining a good ecological environment of the city.High-intensity human disturbance in cities leads to a series of situations such as urban soil compaction,ecological degradation,soil crusting,and decreased permeability.Soil is the foundation of plant growth,soil damage will lead to the decline of urban biodiversity,soil and water conservation capacity,Permeability,nutrient storage etc,will be affected.Fences can reduce human disturbance and help the protection and restoration of bare land and ecologically fragile areas,and the current research on fences focuses on grassland ecological restoration,while research on urban fences is rarely reported.Therefore,in the urban green space of Nanchang,five representative urban parks and one university were selected as the research objects,and the field investigation was carried out to understand the current situation of fence application and human interference.A combination of questionnaires and field research was used to explore the limitations of different fences on people and the reasons for artificially crossing fences.Through field sampling,the differences of plant communities inside and outside the fence(number of species,height,cover,density),the differences in soil physical properties inside and outside the fence(bulk density,porosity,water holding capacity,permeability),and the influence of different degrees of human interference on soil physical properties(CK no interference,LT low interference,MT moderate interference,MST medium and severe interference,ST severe interference)were analyzed,and the main results were as follows:(1)The selected sample plots are subject to different degrees of human interference,and the use of fences is mainly protective fences and isolation fences,which have a better limiting effect on people.There are more man-made crossings of fences below 60 cm height,and fewer crossings of fences above 60 cm height.(2)Different fence materials,heights and widths have different limiting effects on people;The plant fence has a better effect on people,and the same height is better than that of metal fence and wooden fence;When the height of the fence is greater than 90 cm,almost no one is willing to cross,and When the fence width is 60 cm,Visitors’ willingness to cross is relatively low;Visitors often cross fences with motives,among the reasons for crossing,taking shortcuts and following the thought of stepping on the trail have the strongest driving and guidance.(3)There were significant differences in the plant communities inside and outside the fence,and the dominant species inside and outside the fence changed;The ShannonWiener diversity index and Margalef richness index in the fence were significantly higher than those outside the fence.The Simpson Dominance Index and Pielou Uniformity Index were higher than those outside the fence,but the difference was not significant in some sites;The number,height and cover of species in the enclosure and outside the enclosure increased,and the increase of green space with serious disturbance was more significant.(4)There were significant differences in the physical properties of the soil inside and outside the fence;The bulk density of soil outside the fence was greater than that inside the fence,and there was a significant difference(p<0.05),and the infiltration rate was greater than that outside the fence,but the difference between the inside and outside of each plot was different.Soil porosity,water holding capacity,bulk density and permeability were significantly correlated with the inside and outside of the fence(p<0.05).(5)Different intensity of human interference had a significant effect on soil physical properties(p<0.05).Soil bulk density was positively correlated with intensity of human interference(R~2=0.967),and soil porosity,permeability and water holding capacity were negatively correlated with human disturbance intensity(p<0.05).Human disturbance has an impact on both soil topsoil and deep soil,and the most significant impact on topsoil;The bulk weight of grassland is greater than that of the arbor grass structure,weaker than the arbor grass structure under the same interference condition,and the surface permeability of the arbor grass structure is greater than that of the deep layer without interference;There are differences in the permeability of different soil layers,and the overall permeability of deep soil after disturbance is better than that of topsoil.