A Study On Biodiversity Of Urban Green Roof And Its Ecological Value

A series of ecological unbalanced development problems such as air and water pollution,urban heat island effect,rain and flood damage caused by urbanization have become worse increasingly with the rapid development of economy.Green roof is a form of building ecological landscape on the roofs by applying multi-disciplinary theories including urban ecology,architecture and landscape design.It has variety of ecological values such as regulating rainwater runoff,adjusting heat island effect,reducing noise,protecting biodiversity and promoting health aesthetics.The study on the ecological value of urban green roof in terms of vegetation and pollinators will provide a theoretical basis for the planning,design,construction and maintenance management of green roofs.First,literature review and field investigation were adopted in this study.102 plants spicies,including 49 families and 89 genera were concluded through a serious field survey on 14 green roofs in Shanghai.They mainly belong to rose family(Rosaceae),gramineae(Poaceae),crassulaceae(Crassulaceae),oleaceae(Oleaceae)and compositae(Asteraceae).Flower plants could be observed in all four seasons,and there were many varieties of horticultural species and a large proportion of evergreen plants.Although The landscapes were good,the application of local plants,nectar sources,noise reduction and dust removal and other plants of ecological value need to be expanded.Second,environmental facts of green roofs effecting abundance and diversity of pollinators were induced through the literature review.Diversities of bee species were influenced by the building height.Increasing the proportion of green spaces around buildings could increase the numbers of bees and wasps.The connectivity between different bee habitats could significantly affect the scale of bee communities.Frequent activities of bees and other insects between roofs and green spaces around buildings could ensure the pollination of plants.The plant combinations were better than a single species and the native plants were better than alien ones for the pollinator foraging and the pollination of flowers.The use of fine substrates on green roofs could improve the growth of plants and bring about greater ecological value than common substrates.Finally,a plants plan was designed for a green roof in campus of Shanghai Institute of Technology based on the principle of maximizing the ecological benefits of green roof.From the interest of birds and pollinators,a variety of flowering plants were used,trying to increase biodiversity roof by changing the conventional design method.Five types of ecological plant groups were made to attract birds,butterflies and bees,including herbaceous flowers,small shrubs,vines,single species and combinations.This plants plan could provide a reference for creating roof biological diversity in the future.