Climate change, biodiversity and the urban environment: a critical review based on London, UK

Abstract

According to projections by the United Nations, 60% of the world’s population will reside in urban areas by 2030. Studies of the ecology of cities and ecology in cities will therefore assume increasing relevance as urban communities seek to protect and/or enhance their ecological resources. Presently, the most serious threats to wildlife include the degradation and/or loss of habitats, the introduction and spread of problem species, water pollution, unsympathetic management, and the encroachment of inappropriate development. Climate change could add to these problems through competition from exotic species, the spread of disease and pests, increased summer drought stress for wetlands and woodland, and sea-level rise threatening rare coastal habitats. Earlier springs, longer frost-free seasons, and reduced snowfall could further affect the dates of egg-laying, as well as the emergence, first flowering and health of leafing or flowering plants. Small birds and naturalized species could thrive in the warmer winters associated with the combined effect of regional climate change and enhanced urban heat island. This article reviews the range of climate-related threats to biodiversity in the aquatic, intertidal and terrestrial habitats of urban areas. London is used as a case study to illustrate potential impacts, and to contend that ‘green spaces’ in cities could be used by planners to counter climate-related threats to biodiversity, as well as to improve flood control and air quality, and reduce urban heat island effects.