City Nature Challenge 2024 Roma
april 26-29, 2024

Once again, this year between April 26 and April 29 the whole territory of the Metropolitan City of Rome will be involved in the City Nature Challenge (CNC), an international competition between hundreds of cities around the world to map biodiversity and spread the culture of environmental protection, under the coordination of the National Academy of Sciences known as the “Accademia dei XL“.

It will be an event in memory of Prof. Valerio Sbordoni, a member of the Academy, who passed away in 2024 shortly after promoting this initiative, which we dedicate to him with esteem, friendship, and affection.

Valerio Sbordoni at the inauguration of the CNC 2023, in the Castelporziano Presidential Estate

The City Nature Challenge, launched in 2016 on the first Citizen Science Day by the California Academy of Sciences (San Francisco) and the Natural History Museum of Los Angeles County, grew into one of the world’s largest Citizen Science initiatives for biodiversity awareness, a competition to map the presence of plants and animals in urban areas.

In 2023, the initiative involved 482 cities in 46 countries on all continents, with a significant membership of European cities (Athens, Berlin, Copenhagen, Edinburgh, London, Luxembourg, Madrid, Paris, Prague, Wien, Zagreb), with more than 66,000 participants and over 1,800,000 observations of more than 57,000 species.

The challenge was won by La Paz, Bolivia, based on all three parameters considered: number of observations, number of species observed and number of observers. In Europe, Rome was fourth, after Graz, Salzburg and Milazzo, in the number of observations, fifth in the number of species observed – Vienna also overtook us – but first in the number of observers, and this is surely the most important result achieved!

The results of the previous 2023 edition can be found here

The competition in the Metropolitan City of Rome

Using iNaturalist platform (accessible free of charge via an app on a smartphone or computer), citizens or organised groups can document the presence of plants or animals with photos, videos, or audio files (pets, captive animals and cultivated plants are not allowed).

This is an important opportunity to involve citizens, families, and young people to understand the meaning and value of biodiversity in urban ecosystems. The interactive map, developed specifically for this event, identifies where and when BioBlitzes, which are scheduled by the various institutions, parks and associations participating in the project, will take place.

With all the institutional and scientific partners that joined the project launched by the “Accademia dei XL” in Rome, an attempt was made to maximize the search for different species by organising the observations in the widest possible variety of terrestrial and aquatic habitats.

BioBlitzes organised for the CNC 2023.

Consequently, in addition to city parks, coastal lagoon environments were considered, such as the Torre Flavia nature reserve, and purely marine environments as well, by involving teams of divers to photograph marine fauna along the Tyrrhenian coast of the event area. We will try not to neglect the species of fish and crustaceans that are the subject of small-scale fishing in Civitavecchia and Anzio. Inland water habitats will be represented among others by Lake Bracciano and the Tevere Farfa Nature Reserve.

Terrestrial ecosystems will include areas with typical Mediterranean vegetation such as the Presidential Reserve of Castelporziano, or the LIPU oases of Ostia and Castel di Guido, hilly environments well represented by the Monte Catillo Reserve and Monte Soratte, up to mountain environments within the boundaries of the Metropolitan City of Rome such as those included in the Lucretili and Simbruini mountain parks. Finally, we will try to include hypogeal habitats to search for troglofile species in natural and artificial caves.

The 2024 CNC will take place in 2 parts:

  • April 26 – April 29, 2024: the four days when participants will photograph plants and wild animals to upload the observations to iNaturalist, both during scheduled BioBlitzes and free activities.
  • April 30 – May 5, 2024, when they will complete the uploading of their observations and try to identify as many of them as possible using iNaturalist.

For this purpose, the Academy and the scientific partners will organize, if necessary, online sessions on both the use of the iNaturalist platform and how to validate the observations.

This year, our iNaturalist project is configured to NOT collect observations that do not meet iNaturalist requirements (animals in captivity, cultivated plants, absence of photos, audio, or video), those that corresponded to black markers in last year observations (see last image below). This results in fewer observations, but it is a more serious, rigorous, and clean approach, which unfortunately many other cities do not adopt.

The results will be announced on Monday May 6, 2024

CNC 2023 observations


– invertebrates

– vertebrates

– plants

– fungi

♦ – observations that cannot be validated