Study On The Spatiotemporal Variations And Driving Factors Of Carbon Sequestration,Oxygen Release,Cooling,and Humidity Increase In Typical Artificial Lawns And Spontaneous Vegetation In The Guanzhong Region

The intensifying global climate change has elevated carbon emissions and oxygen supply as crucial environmental issues.The ground’s ability to sequester carbon,release oxygen,cool,and humidify is a pivotal element of urban green space ecosystem services.This ability is intricately intertwined with the health and stability of urban ecosystems.Investigating the carbon sequestration,oxygen release,cooling,and humidification abilities of diverse ground cover types holds significant implications for steering the low-carbon city ground cover landscape design and accomplishing the "carbon neutrality" goal.Such study can provide valuable insights and scientific evidence for devising effective strategies for mitigating the adverse effects of climate change on urban ecosystems.Through literature review and field investigation,this study identified and selected 13 common and typical vegetation communities in the Guanzhong area.Among them,there are6 Spontaneous-Vegetation,including "Cynodon dactylon-Artemisia frigida-Kochia scoparia-Bromus japonicus(CAVB)","Cynodon dactylon-Artemisia frigida-Kochia scoparia-Medicago sativa(CAVM)","Cynodon dactylon-Medicago sativa-Kochia scoparia-Brassica juncea(CMVB)","Coreopsis tinctoria-Kochia scoparia-Cynodon dactylon-Glechoma longituba(CVCT)","Cynodon dactylon-Phleum pratense-Kochia scoparia-Coreopsis tinctoria(CPVC)",and "Rubus parvifolius-Adenophora stricta-Potentilla anserina-Elymus nutans(DIDS)".In addition,7 artificial turf communities were established,including "Cynodon dactylon(Cc),Paspalum notatum(Pa),Oxalis corniculata(Oc),Festuca pratensis Huds.var.longifolia(FPL),Festuca pratensis Huds.(FP),Trifolium repens(Tr),and Dianthus chinensis(Dh)",and they were observed and recorded for one year to compare the differences in carbon fixation,oxygen release,cooling,and humidification among different types of vegetation communities.The driving factors behind the differences were also explored.The main conclusions are as follows:(1)The ability of the Spontaneous-Vegetation cover to sequester carbon and release oxygen and to reduce temperature and increase humidity was significantly better than that of the artificial turf.The Spontaneous-Vegetation cover,consisting of "Hydrangea minor-Arabica Bracken-Dog’s tooth root-Ground Cress"(CVCT)as the dominant species,was significantly better than the other ground cover communities in terms of carbon and oxygen sequestration and cooling and humidifying capacity.(2)The daily carbon sequestration and oxygen release and cooling and humidification capacities of the different ground cover types differed significantly between seasons and months of the year.In general,the daily oxygen sequestration and release by each ground cover type was autumn > summer > spring > winter,and the daily cooling and humidification by each ground cover type was summer > autumn > spring > winter.In terms of month,the highest average daily oxygen sequestration and humidification in June,and the lowest average daily oxygen sequestration and humidification in January,December and February were recorded in winter.(3)The ability of ground cover to sequester carbon and release oxygen was strongly correlated with biodiversity,community functional groups and their proportions,but the ability of ground cover to reduce temperature and increase humidity was only correlated with the proportion of functional groups.The ability of ground cover to sequester carbon and release oxygen was significantly correlated with the Shannon index,Simpson index,the proportion of legumes in the community,the proportion of grasses in the community and the proportion of chrysanthemums in the community,but not with the Pielou index.The cooling and humidifying capacity of ground cover was significantly correlated with the Aroma Index,Simpson Index,community legume proportion,community grass proportion and community chrysanthemum proportion,but not with the three indices of community biodiversity.In addition,the daily carbon sequestration and oxygen release of the ground cover communities increased with increasing Aroma Index,decreased with increasing Pielou Index,and increased with increasing legume and forb proportions.Daily cooling and humidification increased with the proportion of legumes.(4)Daily oxygen sequestration and release from ground cover and daily cooling and humidification are related to environmental meteorological factors.The daily oxygen release from ground cover and daily humidity increase were significantly correlated with air humidity and highly significantly correlated with the other four meteorological factors.Among them,the daily oxygen sequestration and humidity release of ground cover had a highly significant negative correlation with atmospheric pressure,and a significant positive correlation with all other factors.The ability of ground cover to sequester carbon and release oxygen decreases with increasing atmospheric pressure;the lower the air humidity and the higher the average monthly rainfall,the stronger the cooling and humidifying ability.(5)Several strategies and suggestions are proposed for promoting the construction and use of strong carbon sink landscape ground cover:(1)improve the design techniques for matching the structure of ground cover plants;(2)protect and utilize self-growing plants in urban green spaces;(3)promote the introduction,acclimatization,and development of self-growing plants;(4)strengthen policy and legal guidance;(5)develop scientific and reasonable methods for evaluating the carbon sink of landscape ground cover;(6)promote public participation and popular science education,etc.In conclusion,this study provides scientific basis for the design of low-carbon urban landscape ground cover by investigating the carbon sequestration,oxygen release,cooling,and humidifying capabilities of different types of ground cover.It has certain theoretical and practical significance for the health and stability of urban ecosystems.