Research Centre for Eco-Environmental Sciences Chinese Academy of Sciences,Research Centre for Eco-Environmental Sciences Chinese Academy of Sciences,,,,,
Urban biodiversity pattern is determined primarily by the local environmental conditions and urbanization processes; its dynamics and underlying mechanisms are fundamentally different from those in natural ecosystems. Nevertheless, biodiversity in urban areas provides a number of ecosystem functions and services which are critically important for improving urban environmental quality and maintaining urban sustainability. Over the world, urbanization has intensely affected the distributional pattern of biodiversity within and around cities, resulting in a series of problems such as reduced native biodiversity, increased exotic biodiversity, and species homogenization of the flora or fauna in an urban landscape. Here we review a number of recent advances in urban biodiversity research by selecting a set of key topics. We find that animal richness has declined definitely without human intervention; Whether urban environment can cause decreasing (or increasing) in plant diversity is still an arguable question, but native and exotic plant species correlate positively in urban environment. Land use change, landscape pattern,climate change, local environment and particularly socio-economic factors affect the distribution pattern of urban plants diversity significantly. Urban landscape has dual effects on biodiversity pattern: landscape fragmentation and natural vegetation disappearance cause decreasing and extinction of native species, while heterogeneous habitats will potentially increase species diversity. We suggest that the selection of a proper temporal-spatial scale is the first step in urban biodiversity study and using qualitative or quantitative urbanization gradient is based on specific question and extent of the study. The species-area relationship and moderate disturbance hypothesis in urban environment needs verified further and. In particular, we emphasize that urban biodiversity research is essential for understanding and maintaining ecosystem functions and services in urban landscapes and deserves a further exploration.