Cooling Effect of Urban Blue and Green Spaces: A Case Study of Changsha, China.

The cooling effects of blue-green spaces on the urban heat island effect are complex and different. The purpose of this study is to simulate how the cooling effect of blue-green space changes with its size and shape. The cooling effects of 53 green patches and 28 water bodies in Changsha were extracted based on Landsat images. A surface fitting model was used to quantitatively reveal the relationship between the cooling effect of blue-green space and its size and shape. The results show that the cooling effects of blue-green spaces were enhanced with the increasing size, and then would become stable after a certain range (threshold). Certain thresholds were identified between the blue and green space areas (2.98 ha and 3.15 ha, respectively) and the cooling distance, and between the blue and green space areas (4.84 ha and 4.92 ha, respectively) and the cooling magnitude. In addition, the green space with an area of 9.08 ha and landscape shape index (LSI) of 2.97 could achieve a better cooling distance (413.46 m); and the blue space with an area of 29.4 ha and LSI of 1.75 could achieve a better cooling magnitude (5.17 °C). These findings provide useful guidelines for urban planning and improving urban livability in other regions with terrain and climate conditions similar to Changsha.

Adaptation and transformation planning for resilient social-ecological system in coastal wetland using spatial-temporal simulation.

Coastal wetlands comprise unique ecological systems such as tidal flats and wetlands coexisting with marine and terrestrial ecosystems. The Songdo wetlands in South Korea are adjacent to the Yellow Sea, and were once composed mainly of tidal flats, but as urbanization progressed, their social-ecological system changed. The social system created by land reclamation and development reduced the migratory bird population and the tidal flat area, damaging the ecological system. This study suggests adaptation and transformation plans by analyzing land use change and fragmentation of the Songdo wetlands using spatial-temporal simulation. System dynamics and GIS were used in the process of analyzing land use change through spatial-temporal simulation, and FRAGSTATS was used in the analysis of wetland fragmentation. Scenario 1 (current state maintenance) presents adaptation plans to increase the connectivity of wetland patches, since fragmentation has not progressed to the extent of wetland system collapse. In Scenario 2 (development acceleration), since the wetland system causes serious fragmentation in terms of area and shape, we propose transformation plans such as disaster response to the collapse of the ecological system and qualitative improvement of wildlife habitat. In Scenario 3 (wetland restoration), proposes transformation plans from the network and modularization perspective in response to quantitative restoration and morphological fragmentation of wetlands. The adaptation and transformation plans presented in this study can provide prediction results suitable for various contingencies such as the current state, acceleration of development, and wetlands restoration. This study is also meaningful in that it proposes plans from the perspective of resilience by predicting the change of the Songdo area, which is scheduled to be developed by 2030.

Key coastal landscape structures for resilient coastal green infrastructure to enhance the abundance of migratory birds on the Yellow Sea.

The aim of this study was to investigate the key landscape structures of migratory bird habitats that affect abundance of migratory birds to promote resilient coastal green infrastructure planning on the Yellow Sea coast. We classified coastal areas into four watersheds of South Korea and conducted multivariate regression analysis between migratory bird populations and landscape structures including total class area (CA), patch area distribution (MN), patch density (PD), and edge density (ED). At the national level, sandbank MN, sandbank CA, water ED, and grasslands were derived as key landscape structures affecting the abundance of migratory birds. At the watershed level, key landscape structures were determined as follows: Urban area_MN for the Han River watershed, rice paddy MN for the Asan watershed, rice paddy CA for Saemangeum, and grassland MN for the Youngsan River watershed. Considering the multifunctionality, redundancy, and connectivity of the resilience strategy, we provide specific coastal infrastructure planning recommendations at the national and watershed scales.