Ecosystem services are defined as benefits that humans obtain from
ecosystem functions, or as direct and indirect contributions from ecosystems to
human well-being. Urban ecosystems are those where the built infrastructure covers
a large proportion of the land surface, or those in which people live at high
densities. They include all ‘green and blue spaces’ in urban areas, including
parks, cemeteries, yards and gardens, urban allotments, urban forests,
wetlands, rivers, lakes, and ponds. Urban ecosystems are especially important
in providing services with direct impact on health and security such as air
purification, noise reduction, urban cooling, and runoff mitigation. Which
ecosystem services in a given city are most relevant varies greatly depending
on the environmental and socio-economic characteristics of each site. For
example, natural barriers to buffer environmental extremes are critical for
cities located in or close to coastal areas (e.g. New Orleans); air quality regulation
can be of significance in cities severely polluted due for instance to
topography of heat inversions (e.g. Santiago de Chile), but may be of secondary
importance in cities where atmospheric pollution is favoured by topography, as
well as policy (e.g. Helsinki). Similarly, while urban green areas will
generally play a secondary role in tourism, emblematic city parks can be an
important part of the portfolio of attractions valued by city tourists (e.g.
the Central Park in New York).
THE ABC FOR SUSTAINABLE CITIES
UNEP / UN HABITAT / FIDIC / GI-REC
Based on
Gómez-Baggethuna E.
and Bartonc David, Classifying and valuing ecosystem services for urban
planning, in Ecological Economics
Graphic: metrovancouver.org
