Green spaces and corridors in urban areas

Recent studies have highlighted the importance of boosting green urban areas and connecting fragments of green space with ecological corridors to improve biodiversity and animal species dispersal within the urban landscape. If adequately designed, green corridors can improve urban ventilation, allowing for cooler air from outside to penetrate into the more densely built areas, and reducing thus the urban heat island effect. Urban green areas can also have positive effects for human health and climate change adaptation. The capacity of vegetation to retain water is an important flood prevention feature that can reduce peak discharges.Green spaces in cities can also provide cooling through shading and enhanced evapotranspiration, thus reducing the heat island effect that occurs in many cities. Green areas are often threatened by expanding city structures, which have fragmented natural areas, creating small patches of green spaces in amongst buildings and roads. For example, patches of urban woodlands are generally separated from each other, which affects the ability of many woodland species to disperse, or move among different locations with similar habitats. Ecological corridors or connections between urban woodlands, gardens or other green spaces are recognised as a way to limit the negative effects of fragmentation. The creation of green areas and corridors can be applicable in most urban areas. The wide array of available techniques allows application in areas with very different characteristics and even where space is limited. Techniques include, for example, green roofs and walls which use vegetation on the roofs and facades of buildings to provide cooling in summer and thermal insulation in winter.