150,000,000 observations on iNaturalist!

This week we passed 150 million observations! While the number of observations has been growing steadily over time, observations per month passed 5 million for the first time this summer.

These observations aren’t equally distributed across space. The map below bins observations in each of 64,800 1x1 degree grid cells covering the globe. Most are in North America and Europe and other hotspots like Taiwan, Eastern Australia, Cape Town etc.

In the past posts, we’ve explored how observations are unevenly distributed across species. In the graph below, we’re doing the same with land area. The black line ranks all land surface (excluding Antarctica) 1x1 degree cells by number of observations. On the left are cells that encompass very observose cities such as Hong Kong with nearly 1 million observations. On the right are cells with very few observations such as the cell encompassing Kananga in the Congo Basin of Africa with just 3 observations. 40% of non-Antarctica land surface cells have no observations at all.

This graph shows how that line has shifted to the right as iNaturalist has grown from 50 million observations (dark green line) to 100 million observations (middle green line) and to 150 million observations (light green line). The percentage of land surface excluding Antarctica with at least 1,000 observations has grown from 12% to 20% with this tripling of observations.

This 1,000 observation threshold is a totally arbitrary cutoff representing grid cells with reasonably high densities of observations. Mapping them we can see light green (cells reaching 1,000 observations from the most recent 50 million observations) encroaching into gaps on the map. As is the case with tallying rare species, tallying observations from remote places proceeds much slower than the overall number of observations since most observations come from a relatively small number of places.

The graph below shows these changes in the percentage of cells with at least 1,000 observations for the United States, China, Africa, and Europe (excluding Russia which spans Europe and Asia).

In Europe (excluding Russia) and the United States, most cells now have over 1,000 observations (78% and 70% respectively). However, the percentage of cells with over 1,000 observations in Europe has increased relatively rapidly (from 53% to 78%) as observations across Eastern Europe fill in. In contrast the percentage of cells in the US is increasing more slowly (from 61% to 70%) as the remaining cells with few observations are in remote areas like northern Alaska. In Africa and China the percentages of cells with at least 1,000 observations is much lower (14% and 9% respectively).

Many parts of the world have few observations because they are so remote and so few people live there. It’s unclear what we can do to encourage more observations from such places. But as projects like City Nature Challenge show, it’s possible to get lots of participation from places where lots of people live. The graph below shows the 590 cities with populations over 750,000 people in 2010 ranked by number of observations. Cities in North America and Europe are colored in green while cities in Asia and Africa are in gray. Cities from other continents are shown in white. Most of the places in the world where lots of people live and we have few observations are in Asia and Africa. Engaging more people who live near these cities will be important part of increasing the geographic distribution of iNaturalist observations moving forward.

Thank you to everyone who has contributed to this 150 million observation milestone! If you’re inspired to donate, you can do so via the link below.

Donate to iNaturalist

Posted on July 28, 2023 10:24 PM by loarie