Citizen scientists can document Earth’s biodiversity in the upcoming global City Nature Challenge

The eighth annual City Nature Challenge (CNC) is fast approaching, when citizen scientists across the globe will compete to document biodiversity in more than 450 cities, across six continents.

The CNC is a four day global bioblitz where cities compete against each other to be the one that makes the most observations of nature, finds the most species, and engages the most people.

From 28 April at 12:01 am in each time zone until May 1, 11:59 pm, people of all ages and backgrounds can observe and submit photographs of wild plants, animals, and fungi using the free iNaturalist mobile app.

Citizen scientists taking photos of marine life
Pillar Point Bioblitz, California, US. Credit: © Gayle Laird CAS

Don’t worry if you don’t know exactly what you photograph! Species will then be identified by teams of experts from 2-7 May with results announced on Monday 8 May.

“The biodiversity data collected through community science events like the City Nature Challenge cannot be gathered any other way,” says Alison Young, co-director of Community Science at the California Academy of Sciences and co-founder of the Challenge.

“Understanding exactly where in the world species are found really does take all of us, and is critical to conservation, stewardship, and regeneration of nature.”

During last year’s Challenge, over 67,000 participants added over 1,690,000 observations of nature to iNaturalist, and scientists continue to use these data to understand and conserve urban wildlife.

Two coyotes in a green park
Two coyotes search for food scraps in San Francisco’s Golden Gate Park, US. Credit: © Stephen Riffle

There were over 2,000 observations of rare and endangered species made, from recordings of the critically endangered white-backed vulture in Botswana to the near-threatened flame robin in Australia.

Outside of La Paz in Bolivia (which came in first place with the highest number of observations for 2022) a citizen scientist submitted the fourth recording of a Bolivian racer snake in 20 years and the first on iNaturalist. A new species of orchid from the genus Telipogon was also discovered in the nearby town of Coroico.

A bird swooping down to pick up something floating at the surface. Image taken during the 2022 city nature challenge in hong kong.
A whisked tern, documented in Hong Kong during the 2022 City Nature Challenge. Credit: © il0214

“The City Nature Challenge is the only global event that uses the iNaturalist platform,” says Anabela Plos, City Nature Challenge Spanish Language Global Organiser.

“The sheer scale of this four-day event provides a unique opportunity to make and share observations of nature from around the world and expand our collective biodiversity knowledge.”

So, how can you get involved in 2023?

  1. See participating cities here.
  2. If you’re an educator check out the CNC Education Toolkit, with activities for both formal and informal education settings.
  3. Go out and find wildlife – it can be any wild plant, animal, fungi, slime mould, or evidence of life (scat, fur, tracks, shells, carcases). Explore this helpful guide for tips on how to find and document biodiversity in and around your own home.
  4. Take pictures and/or sound recordings of what you find using iNaturalist.
  5. Learn more as your observations get identified!

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