Your call for more investigation into the ecology of urban habitats (see Nature ; 2010) is already being answered.

In 1997, the US National Science Foundation's Long-Term Ecological Research programme created urban research sites in Baltimore, Maryland, and in Phoenix, Arizona. And last year the foundation funded the Urban Long-Term Research Area Exploratory Awards with the US Forest Service to expand knowledge of urban natural resources and human interactions. These programmes attest to a coordinated and productive effort to incorporate urban research into mainstream ecology.

Publications on this topic have mushroomed over the past two years: they include specialist journals (Urban Ecology, Urban Ecosystems); a 'Cities' special in Science (319, 739–775; 2008) and books such as Urban Herpetology, Urban Carnivores and Advances in Urban Ecology.

Membership of the Urban Ecosystem Ecology section of the Ecological Society of America is growing fast — it is now the twelfth largest of 19 sections. There were 202 urban-related items presented at the society's annual meeting last month, compared with just one in 1991.

Although the number of published urban studies is still small, it is rapidly increasing. Only 0.4% of papers in nine leading ecology journals in 1993–98 dealt with cities or urban species (J. Collins et al. Am. Sci. 88, 416–425; 2000), compared with 2.5% of papers in 10 top ecology journals over the past 5 years (see

Urban environments were not even recognized as ecosystems until recently. To understand the impact of human activity, we need to compare the entire range from pristine to altered systems. Many ecologists are already up to the challenge.