Nicholas School of the Environment, Duke University, Durham, North Carolina

An ecologist calls for a citizen-science 'Wiki'.

Where do species occur and why? What happens to ecological communities when species are removed or when alien species invade? And how will the answers shift as climates change? These questions span huge spatial and temporal scales, and involve millions of species. By contrast, ecological field studies are generally of short duration, include few species and cover small areas. This means that getting data for the big questions is a tall order — impossible without harnessing a deeper reserve of people power.

Citizen science — in which qualified scientists oversee volunteers — is not new. The Audubon Society's Christmas Bird Count has run for 108 years and mobilizes about 60,000 volunteers across 1 million square kilometres of North America who count about 58 million individual birds annually. Other citizen-science projects are under way around the world.

Dirk Schmeller at the Helmholtz Centre for Environmental Research in Leipzig, Germany, and his colleagues analysed 395 citizen-science projects across five European countries, involving more than 46,000 participants (D. Schmeller Conserv. Biol. 23, 307–316; 2008). Volunteers donated more than 148,000 person-days per year, a figure inconceivable using professional scientists alone. Schmeller et al. found that volunteer-gathered data are reliable and unbiased, with data quality determined less by 'volunteer' status, and more by survey design and methodology.

The rapid increase in citizen-science data sets can revolutionize what we know about the natural world. Wikipedia has shown that the public is willing to donate time, talent and knowledge, given a sufficient platform. Biodiversity data lack such a platform for input, integration, mapping and dissemination. This is a deficiency that the environmental community should address.