Animal population estimates may be skewed by inaccurate data-but implementing technology to develop a more accurate estimate might put a lot of animals on the endangered list and cause an extinction crisis.
Here's how it all works:
To determine population estimates of the Earth's animals (after all who could be sure) we currently use the International Union for Conservation of Nature and Natural Resources’s (IUCN) Red List.
“It’s the international standard,” says Stuart Pimm, but we'll get to him later.
We've been using it since 1964 and it's a huge group effort. For an accurate estimate scientists, conservationists, volunteers and naturalists submit studies and data. This information is then entered into an algorithm by IUCN officials which accounts for factors like habitat loss, habitable area and population trends. The result is a ranking for each species on the Red List.
It's not an all-or-nothing scale, as you can see below. There are varying shades of extinction. I should also note (before I share some stats) that the list rates mammals, birds, reptiles, amphibians, fish and invertebrates, as well as plants.
The current Red List contains 82,954 species: 4,749 critically endangered, 61 extinct in the wild and 10,694 species that are vulnerable right now. So already high numbers.
But here's the controversy:
According to Stuart Pimm (I mentioned him earlier) the Red List is using outdated maps to determine deforestation and encroaching civilization instead of aerial imaging. He also claims the data used to create the list might be overestimating the area of livable habitat for each species, resulting in an inflated estimate of animal populations.
Now not only is Pimm a Doris Duke Professor of Conservation Ecology at Duke’s Nicholas School of the Environment, but he tested this theory with his team and they recalculated 586 bird species by incorporating current technology.
“Good as it is, the Red List assessment process dates back 25 years and does not make use of advances in geospatial technologies that have placed powerful new tools at our fingertips, including vastly improved digital maps, regular global assessments of land use changes from satellite images, and maps showing which areas of the planet are protected by national parks.” -Stuart Pimm
After recalculating the area of viable habitat with remote-sensing data on forest coverage and elevation, Pimm and his team plugged their new numbers into the IUCN's algorithm.
The results were shocking: 210 of the 586 bird species would move up at least one threat level category on the scale of extinction.
For example, the grey-winged cotinga (currently listed as vulnerable) has a habitable area of 1,274 square miles according to the current algorithm, which also takes into account that this bird only lives at elevations of 3,937 to 5,906 feet.
But according to Prim's team, only 38.6 square miles actually qualify as viable habitat, which escalates the cotinga's status to critically endangered.
And while Pimm and his team tested a small sample of birds, it's believed that his findings (and methods) could impact mammal and amphibian estimates as well.
Stuart Butchart, the head of science for BirdLife International in Cambridge, U.K., (and an organization tasked with tracking birds for IUCN) says the team overestimated their findings and used the wrong parameters, but they defend their approach.
Either way, it's clear that aerial and satellite mapping technology can help researchers better estimate wild animal populations and habitat. But if Pimm's methods are adopted and they reveal a more accurate picture of animal populations, we can expect to see an extinction crisis.