Changes And Resilient Recovery Of Recreational Flow Network In Urban Blue-Green-Gray Space Under The Impact Of COVID-19

The COVID-19 pandemic has had a significant impact on people’s outdoor recreational activities.However,despite the increasing attention to this topic in recent years,little is known about how the pandemic affects tourists’ intercity recreational travel decisions,their choices of urban blue-green-gray spaces for recreational destinations and travel modes,and the resilience of urban blue-green-gray recreational systems under the impact of the pandemic.This study reveals the spatial spillover effect of intercity recreational flows with Wuhan as the destination and the changing characteristics of recreational path structures among blue-greengray spaces within Wuhan before and after the pandemic.Furthermore,it discloses the overall network,key functions,and roles in the urban blue-green-gray recreational flow structural network and functional network.By evaluating the resilience of the blue-green-gray recreational flow structural network and functional network in different quarters and the key nodes that affect resilience,we construct a post-pandemic recreational flow network recovery model and propose a comprehensive optimization system for the post-pandemic recreational system.This provides a new perspective for recreational flow research and offers guidance for the systematic development of Wuhan’s blue-green-gray recreational spaces post-pandemic.The main research findings are as follows:(1)A study on the changes in urban blue-green-gray recreation flow spillover and recreation path structure found that the cross-city recreation flow spillover distance has decreased by 64.37 km after the pandemic,but the spillover direction remains unchanged.The spillover distance to blue spaces as destinations has increased by 45.45 km,while the spillover distance to green and gray spaces has decreased by 73.07 km.The recreation paths within the city for both out-of-town tourists and local residents in blue-green-gray spaces exhibit a simplification trend.However,after the pandemic,the average length of recreation paths for out-of-town tourists increased by 28.88 km,while it decreased by 12.28 km for local residents.For out-of-town tourists,the proportion of gray spaces in the recreation paths increased when the length exceeds 123.25 km or the number of nodes exceeds 7.97,while the proportion of green and blue spaces decreased.For local tourists,in the recreation paths with a length between 15.12 km and 42.43 km,or the number of nodes between 2.39 and 5.54,the proportion of blue and gray spaces slightly decreased,while the green spaces increased.(2)Research on the changes in urban blue-green-gray recreation flow network characteristics found that the weighted average clustering coefficient of the structural network is only 0.15,indicating that local connections are not tight enough,and the core recreation spaces are concentrated on both sides of the Yangtze River.The average weighted node degree,clustering coefficient,and network connectivity,which represent the overall level of functional networks,showed that the first two indicators for out-of-town tourists decreased by0.59 and 0.15,respectively,while network connectivity increased by 0.02.For local residents,the first two indicators also decreased,by 1.34 and 0.07,respectively,but network connectivity did not change.This shows that both local residents’ and out-of-town tourists’ networks have experienced simplification after the pandemic,with local residents being more severely affected.In terms of node functions and roles,the main changes in the network for out-oftown tourists are in the balanced and clustered gray spaces,while for local residents,they are in the diffusive gray spaces.Nodes that did not change in the network for out-of-town tourists are mainly in the diffusive green and gray spaces,while in the local residents’ network,they are mainly in the clustered gray and green spaces,and diffusive green spaces.Further analysis of networks in different seasons reveals that out-of-town tourists are less inclined to visit the next destination during multi-purpose trips after the pandemic,while local residents prefer long-distance and fewer-destination recreation trips.(3)The urban blue-green-gray recreational flow network resilience assessment study finds that the structural networks of non-local tourists have basically recovered since the second quarter of 2021,while those of local residents have recovered since the third quarter of 2020.As for the functional networks,non-local tourists’ overall resilience is better than that of the structural networks,also recovering to pre-pandemic functions since the second quarter of 2021.In contrast,local residents’ overall resilience is worse than that of the structural networks,with recreational efficiency exceeding the threshold only in the third quarter of 2020 and the first quarter of 2021.Regarding the key nodes affecting network resilience,non-local tourist structural network key nodes in different quarters are all Jianghan Pass Tower,but their proportions have been increasing year by year,with the spatial types mainly being gray spaces.Local residents’ key nodes include Mulan Tianchi,Yellow Crane Tower Park,and Guanggu Square,with recreational efficiency dropping to68.5% in the second quarter of 2021,indicating a poor network system,and gray spaces remaining the primary type.The key nodes in non-local tourist functional networks mainly include Wuhan University,Yellow Crane Tower Park,Hubu Alley,and the Yangtze River,with the Yellow Crane Tower Park appearing the most frequently.Except for the first quarter,blue space key nodes have the largest impact proportion.The local residents’ functional network mainly features Wuhan Yangtze River Second Bridge,Hankou Riverside Park,and East Lake Tingtao Scenic Area,with blue-green-gray space key nodes having the most severe impact in the second quarter,particularly green spaces,while recovering well at other times.(4)The study of the urban blue-green-gray recreational flow network recovery model finds that the main recovery areas for non-local tourists are the gray and green spaces around the Yellow Crane Tower Park on both sides of the Yangtze River,and gray spaces such as Jianghan Road Pedestrian Street,radiating outward from these dual central areas.For local residents,the primary recovery areas are the blue-green spaces along the East Lake perimeter and the blue spaces along both sides of the Yangtze River.(5)Based on the spatiotemporal changes of recreational flow spatial spillover,path structure,and network characteristics,as well as the recovery model constructed through network resilience assessment,this study proposes a comprehensive optimization strategy for the post-pandemic recreational system from regional,network,and spatial perspectives.This strategy aims to assist the rapid recovery of urban blue-green-gray recreational space service functions in the post-pandemic era and support the more resilient and sustainable optimization and development of the recreational system.