Monitoring Urban Green Infrastructure Changes and Impact on Habitat Connectivity Using High-Resolution Satellite Data

Construction and optimization of Green Infrastructure Network in mountainous cities: a case study of Fuzhou, China

Green infrastructure networks enhance the protection and improvement of urban ecological environments, augment the efficiency and quality of ecosystem services, and furnish residents with healthier and more comfortable living conditions. Although previous research has investigated the construction or optimization methods of green infrastructure networks, these studies have been relatively isolated and lacking in case studies for mountainous cities. In the development of green infrastructure, mountainous cities must specifically consider the impact of terrain on network construction. Taking Fuzhou, a mountainous city in China, as an example, this study constructs and optimizes the green infrastructure network by employing morphological spatial pattern analysis, connectivity analysis, the Minimum Cumulative Resistance model, and circuit theory. These methodologies increase the connectivity of the Green Infrastructure within the study area, thereby promoting the health of the local ecosystem and creating conducive circumstances for the city's sustainable development. The findings reveal that: (1) Green infrastructure in Fuzhou takes up 5366.38 ha, constituting 21.76% of the study area, primarily situated in the northwest and south; (2) Fuzhou's Green Infrastructure network comprises 10 hubs and 17 corridors with a hub area of 1306.98 ha, predominantly distributed in the mountains encircling the city, including Meifeng Mountain, Gaogai Mountain, and Qingliang Mountain; (3) Based on optimization, the circuit centrality index categorizes hub importance into three protection levels, pinpointing nine crucial protected areas in the corridors and 680 areas requiring enhancement, including 68 areas for first-level improvement, 149 areas for second-level improvement, and 463 areas for third-level improvement. This research offers a methodological reference for constructing and optimizing green infrastructure networks in mountainous cities, providing both theoretical and practical foundations for optimizing green infrastructure networks in Fuzhou City.

Factors responsible for Ixodes ricinus presence and abundance across a natural-urban gradient

To better understand the spatial distribution of the common tick Ixodes ricinus, we investigated how local site factors and landscape characteristics influence tick presence and abundance in different greenspaces along the natural-urban gradient in Stockholm County, Sweden. Ticks and field data were collected in 2017 and 2019 and analyzed in relation to habitat type distributions estimated from land cover maps using geographical information system (GIS). A total of 1378 (992 larvae, 370 nymphs, 13 females, and 3 males) questing ticks were collected from 295 sampling plots in 47 different greenspaces. Ticks were present in 41 of the 47 greenspaces and our results show that both local site features such as vegetation height, and landscape characteristics like the amount of mixed coniferous forest, significantly affect tick abundance. Tick abundance was highest in rural areas with large natural and seminatural habitats, but ticks were also present in parks and gardens in highly urbanized areas. Greenspaces along the natural-urban gradient should be included in surveillance for ticks and tick-borne diseases, including highly urbanized sites that may be perceived by the public as areas with low risk for tick encounters.

Spatio-temporal evolution characteristics analysis and optimization prediction of urban green infrastructure: a case study of Beijing, China

The reasonable layout of green infrastructure is conducive to the low-carbon, livable and high-quality sustainable development of cities. The framework of spatio-temporal evolution characteristics and prediction analysis of Urban Green Infrastructure (UGI) was constructed by integrating morphological spatial pattern analysis (MSPA) and CA-Markov in the study. We analyzed the spatio-temporal evolution characteristics of UGI in Beijing from 1990 to 2019, predicted its future change trend in 2030, and put forward the optimization scheme for the ecological network of UGI. The area change of UGI presented a "V" shape from 1990 to 2019 in Beijing, and the turning point was around 2009. Its spatial distribution revealed a significant heterogeneity. The comprehensive change rate index showed a "rising and then falling" trend from 1990 to 2019. Core with an area of over 1000 km² had inclined "C" shape, connecting the north, west and south of the study area. Among the three prediction scenarios for 2030, the area of UGI under the ecological conservation priority scenario is the largest, accounting for 86.35% of the total area. The area of UGI under the economic development priority scenario is the smallest, accounting for 76.85%. The optimization of zoning and road network are effective measures to improve the connectivity of UGI in Beijing. This study is beneficial to extend the research ideas of UGI and promote sustainable urban development.

Evolution Analysis of Ecological Networks Based on Spatial Distribution Data of Land Use Types Monitored by Remote Sensing in Wuhan Urban Agglomeration, China, from 2000 to 2020

Construction and protection of ecological networks (ENs) is considered to be an effective means to curb habitat fragmentation and strengthen landscape connectivity. In this study, a complete evaluation framework of ENs based on “quality–function–structure” was proposed to support the formulation of protection strategies for ENs. First, we built the ENs of Wuhan urban agglomeration (WUA) from 2000 to 2020 based on the advantages of circuit theory and remote sensing data of land use monitoring. The results showed that land development activities are an important driving force for the temporal and spatial evolution of global ENs. Forest fragmentation, transitional urban expansion, and agricultural reclamation were important inducements for the shrinkage of ecological sources. They may also increase the resistance of species migration, which will lead to qualitative change and even fracture of ecological corridors. Second, circuit theory, centrality index, and complex network theory were applied to evaluate the quality defects, functional connectivity, and topology characteristics of ENs in WUA, respectively, from 2000 to 2020. The results showed that the antagonism between ecological corridors and land development activities led to ecological quality defects (ecological barriers and pinchpoints). Different land development models had differential effects on centrality indexes. Moreover, the main trunk in the northern Dabie Mountains and the southern Mufu mountains was developed, while the secondary trunks were abundant in the middle of WUA. Finally, we proposed protection strategies for ENs based on the coupling of the “quality–function–structure” of WUA in 2020. It is suggested that all ecological sources must be included in nature reserves to prevent natural or manmade erosion. The key areas to be repaired were determined through the quality evaluation of ecological corridors. The priority of construction and protection of ecological corridors was determined by coupling two topological structures and functions. We argue that specific protection strategies and directions can be determined according to the construction objectives of local ENs.

Green infrastructure connectivity analysis across spatiotemporal scales: A transferable approach in the Ruhr Metropolitan Area, Germany

Developing green infrastructure (GI) has drawn increasing attention as a strategic planning approach for advancing urban sustainability. The connectivity of green spaces, a central principle of GI, has been considered in planning studies regarding its structure and functions for biodiversity conservation and ecosystem services delivery; however, aspects of GI connectivity across temporal and spatial scales are rarely addressed. This paper aims to develop and apply a method for the GI connectivity analysis at multiple spatiotemporal scales. A transferable and multi-scale workable approach is presented to reveal the changes of structural and spatial heterogeneity of urban GI. Our method includes i) morphological spatial patterns analysis for central and green corridors recognition, ii) a graph-based quantification of GI connectivity based on the Conefor model, and iii) least-cost path analysis for identifying potential green corridors. We apply the GI connectivity analysis method in the Ruhr Metropolitan Area (RMA), one of Europe's largest agglomerations. We use spatial Urban Atlas data from 2006 to 2018. At the metropolitan scale, we find that GI connectivity in the RMA decreases 3.9% from 2006 to 2018, even though the general distributions of GI changes only slightly. With reference to the municipal scale from 2006 to 2018, four major types of GI connectivity changes were discovered in RMA's 15 cities, namely consistent decreasing, consistent increasing, increase followed by decrease, and vice-versa. Our findings provide new evidence on GI connectivity changes across a twelve-year difference and at metropolitan and municipal scales, as well as the identification of priority areas for increasing GI connectivity. It provides insights on the evolving and heterogenous nature of GI connectivity in support of decision-making for more sustainable metropolitan development for people and nature.

Municipal Practices for Integrated Planning of Nature-Based Solutions in Urban Development in the Stockholm Region

Urban planning is assumed to play an important role in developing nature-based solutions (NBS). To explore how NBS is addressed in urban development, municipal planning practices are analyzed based on three case studies in the Stockholm region of Sweden. Through focus group discussions, interviews and document studies, the planning and implementation of NBS and their intended contribution to regional green infrastructure (GI) and social and ecological qualities are investigated. The results show that the planning and design of urban green spaces engages the local community. Moreover, different conceptual frameworks are used to strengthen an ecological perspective and nurture expected outcomes, in particular ecosystem services and GI. Through competence development and collaborative approaches, the co-creation of innovative solutions for public and private green spaces is promoted. However, institutional conditions, e.g., legal frameworks and landownership shape the planning process and can challenge the ability to enhance social and ecological qualities. An assessment of the planning processes indicates a strong focus on ecosystem services and local GI, while the potential to contribute to regional GI differs widely between cases. The study concludes that a knowledge-driven and integrative planning process can foster the potential of NBS for green and sustainable cities.

Urban Green Infrastructure Monitoring Using Remote Sensing from Integrated Visible and Thermal Infrared Cameras Mounted on a Moving Vehicle

Climate change forecasts higher temperatures in urban environments worsening the urban heat island effect (UHI). Green infrastructure (GI) in cities could reduce the UHI by regulating and reducing ambient temperatures. Forest cities (i.e., Melbourne, Australia) aimed for large-scale planting of trees to adapt to climate change in the next decade. Therefore, monitoring cities' green infrastructure requires close assessment of growth and water status at the tree-by-tree resolution for its proper maintenance and needs to be automated and efficient. This project proposed a novel monitoring system using an integrated visible and infrared thermal camera mounted on top of moving vehicles. Automated computer vision algorithms were used to analyze data gathered at an Elm trees avenue in the city of Melbourne, Australia (n = 172 trees) to obtain tree growth in the form of effective leaf area index (LAIe) and tree water stress index (TWSI), among other parameters. Results showed the tree-by-tree variation of trees monitored (5.04 km) between 2016-2017. The growth and water stress parameters obtained were mapped using customized codes and corresponded with weather trends and urban management. The proposed urban tree monitoring system could be a useful tool for city planning and GI monitoring, which can graphically show the diurnal, spatial, and temporal patterns of change of LAIe and TWSI to monitor the effects of climate change on the GI of cities.