Sometimes Twitter teaches me the most interesting things. Apparently yesterday was Penguin Awareness Day, which I found out when someone I knew retweeted this:
I was intrigued by the color coding under each, and was rather curious what the difference between “endangered”, “vulnerable” and “near threatened” were. Since I’m always on the lookout for faux classifications, I was wondering if those were random categories, or if they had some sort of basis.
Turns out, it’s actually the latter! This is probably well known to anyone in to conservation, but the classification system is actually put out by the International Union for Conservation of Nature. It looks like this:
They publish a rather extensive document detailing each category, and apparently they update this document every couple years. The entire goal of this classification system was to bring some rigor to the process of assessing different species populations, and they have some interesting guidelines.
For example, if a species population drops due to known and/or reversible causes, the size of the drop dictates their status. A drop of >90% in 10 years (or 3 generations) gets you labeled critically endangered, >70% gets you labeled endangered, and a drop of >50% gets you a “vulnerable” label. “Near threatened” doesn’t have a number, but would apply if there was growing concern/problems that didn’t meet any of the other criteria. They play out some other scenarios here. All of the criteria include numbers plus ongoing threats, so there are a few different cases for each.
For example, a critically endangered species could have <250 mature individuals + a threatened habitat, or <50 mature individuals with no threat. For endangered animals, those numbers are 2500 and 500 respectively, and for vulnerable animals it’s 10,000 and 1000. I was interested to note that they include quantitative models as a valid form of forecasting extinction.
Anyway, whether you agree with the criteria or not, it was nice to know that someone’s actually tried to define these terms in a transparent way that anyone can read up on. Hopefully that means these guys will be okay: