8b. 3000.000 soorten waargenomen op iNaturalist

Op de hoofdpagina, Blog pagina van iNaturalist verscheen net vandaag een leuk stuk over de 300.000 soorten dat op iNaturalist.org doorgegeven is terwijl er in de wereld 2 miljoen soorten in totaal zijn. 80% is dus nog niet gezien door de deelnemers. We zien dat insecten en planten de grootste bijdrage leveren maar dat dit ook de soortenrijkste groepen zijn. In de grafieken beneden stelt elk vierkantje 1.000 soorten voor.


It’s interesting to compare this number with the total numbers of species that we think are out there. Most agree that there are around 2 million species with names and that many more species exist that haven’t yet been named. We use IUCN’s numbers from 2010 which tally 1,740,330 species of plants, animals and fungi. Using this denominator, iNaturalist has now censused about 17% of all named species.

The figure below shows this split out by taxonomic category. Each square represents 1,000 species. There are 1,740 total squares and 300 green squares representing the subset observed on iNaturalist.

Most of the species on iNaturalist represent plants and insects but these are also the most speciose groups. In fact, even though the same number of plant and insect species have been observed on iNaturalist (roughly 100,000 each), this represents a much smaller fraction of the total insect diversity (11%) versus the total plant diversity (33%).

The group with the smallest percentage of species observed was Arachnids (8%) and the four terrestrial vertebrate groups (birds, reptiles, amphibians, and mammals) were the only groups with greater than 50% observed. The denominators are probably underestimated as new species have been described since these IUCN numbers were released in 2010, but these percentages are likely not too far off.

In addition to thinking about how many species we’ve observed on iNaturalist, it’s interesting to consider how quickly we’re accumulating new species. The graphs below show the numbers of species observed on iNaturalist over time. The graph on the left is for North American Birds and the graph on the right is for South American Fish. For North American Birds, we do seem to be reaching a plateau (i.e. we've running out of missing species). In fact, over the last 12 months we’ve averaged 19,696 North American Bird observations for each new species tallied. In contrast, for South American Fish the number of species does not seem to be plateauing at all. Over the last 12 months we’ve tallied a new species for every 14 observations of South American Fish added on average.

Here’s the species groups and continents (e.g. South American Fish) where we’ve averaged fewer than 100 observations to tally a new species sorted by this obs/sp stat. Underrepresented groups like fishes and mollusks are over represented in this subset as are continents like South America and Africa.

These are the species groups and continents where we’ve averaged more than 100 and fewer than 1,000 observations to tally a new species.

Lastly, these are the species groups and continents where we’re averaging over 1,000 observations to log a new species. Here, North America and Europe dominate alongside over represented groups like birds and other terrestrial vertebrates.

To tally a new species on iNaturalist, several things have to happen: we need observations from that taxonomic group and location to be posted, the images must reveal enough detail for the species to be identified, and someone with the skills, time, and interest needs to provide an identification. There are steps you can do at each point in this process to increase the overall rate.

To generate more observations, spend some time observing taxa in places you don’t normally visit. If you focus mainly on terrestrial vertebrates, try observing some fish and invertebrates. Invest in some gear to attract or capture creatures you don’t normally encounter like a moth light or aquatic sampling gear or a macro lens for your phone. Try to get others observing by organizing a bioblitz.

To increase the probability your observations will be identified, do your best to take identifiable photos. If you are an identifier specializing in a certain group, write a journal post to encourage people to pay attention to the characters you know are important. Also, engage with observers. Often they can relocate the critter and take photos of the characters you want as in this exchange between @agapakisnikos and @naufalurfi:


8b. 3000.000 soorten waargenomen op iNaturalist



Publicado por ahospers ahospers, 21 de enero de 2021


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