Conservation, development and logistic functions of BRs can be supported by urban green areas with a biological conservation hierarchy, starting with undisturbed ecosystems of a high biodiversity value through urban green systems and biodiversity improvement practices. The conservation function of BRs can be broadened to include degraded ecosystems and habitats to enhance biodiversity. In other words, the major goal of BRs, ‘to protect unique habitats and ecosystems,’ has to be expanded to the areas under pressure because of degradation caused by urban development.