Urban Ecology: of or in? September 4 th, 2014

Cities Agglomerations of people and their activities Multispecies, but it is humans that make a system urban

Characteristics of urban areas Large human populations Large facilities High density settlement Less agriculture, more industry and services

Urban ecosystems are not functionally complete Spatially limited area with high density of consumers with distant support systems

Cities as centers of immigration and adaptation For species tolerant of human activity, cities provide food resources and protection from predators

Cities as centers of trade Deliberate introductions for horticulture, landscaping, pets Accidental introductions as a consequence of commerce

Biodiversity along rural-urban gradients Increasing human impact from rural fringe to city center Biodiversity often lowest in densest areas of cities, but peak is often at the urban fringe – heterogeneous land use – intermediate levels of human disturbance

Urbanization is not inherently bad for ecosystems Support more biodiversity than industrial agricultural 3% of land area, 50% population

Challenges in urban systems Scarcity of natural services Water, sanitation, waste at high densities Concentrated human activities Limited natural infrastructure

What do you think? Ecology in CitiesEcology of Cities

Ecology in cities Forests, wetlands, grasslands, etc. within urban areas Traditional ecosystem analysis Recreation, aesthetic benefits, atmospheric and water regulation Human activity disturbs ecosystem dynamics- outside force

Ecology of Cities Treating urban system as ecosystem Fluxes of energy, material, organisms Human activity a major component of ecosystem dynamics Social as well as biophysical dimensions

Characteristics of urban ecosystems High human population density High proportion impermeable land cover Low density of many indigenous species High rate of species introductions High habitat diversity and fragmentation High rate of human disturbance

Urban approaches to conservation Sustainable use of ecosystem goods and services for and within cities Conservation of biodiversity within towns and cities and the design of of urban areas to maximize their ability to support biodiversity