I photographed a moth at my back porch light the other day which I assumed was a washed out Spotted Tussock (Lophocampa maculata) and posted it, as I do most of my moth photos, on iNaturalist.
I got a correction from Jim Johnson yesterday. It is not what I thought it was. It’s a Roseate Tussock (L. roseata), a rare-ish Pacific Northwest endemic (though there are a couple disjunct records from Colorado and Arizona). This is only the second record for Oregon. It is listed on the NatureServe watchlist as Critically Imperiled.
But what does critically imperiled mean? and who decides?
Assessing these sorts of things can be complicated. Folks who live in the middle of a population might see a given organism as common, while folks who live outside that range may value it as rare. Folks who have a vested interest in the places where an organism lives may be biased one way or the other about the legal issues that come with a tag like “critically imperiled”. The Roseate Tussock is NOT listed as threatened or endangered by the USFWS. Its official status in Washington State and British Columbia is, in fact, “species not ranked”.
NatureServe uses an objective, data driven approach to these assessments. They have a formula which assesses rarity factors, population trend factors and habitat threat factors to score an organism’s risk of extinction. The score an organism receives is an objective, numbers thing and the ranking is more or less automatic based on the calculated score. Not much is known about the Roseate Tussock. No one is sure what the larval host plants are or what the specific habitat needs might be. It has a restricted range and hasn’t been seen by very many people. The NatureServe calculator lists this species as critically imperiled precisely because we know so little about its true status.
And when you think about it, this is actually a good thing. Endangered species protection over the last 50 or so years has been all about crisis management. Waiting until we can say with certainty that a species is on the brink of extinction and then acting. It strikes me that erring on the side of protection before a species is nearly gone is a more cost effective, long-term approach to these kinds of management issues, especially given that we know so little about so many things in nature…