There is a lot of scientific terminology out there; how can anyone know what it all means? I work in the conservation field and sometimes even I am not 100 percent sure what all the terms means in relation to the commonness or rarity of a species, so I will try to give a brief summary here…
When talking about threatened, endangered and extinct species, it helps to know whether you are discussing it from the state, federal or international perspective, because each may have slightly different definitions and regulations. In terms of the U.S. federal government, some species fall under the Endangered Species Act. Richard Nixon created this Act in 1973 to protect “imperiled” species from extinction caused by human development and economic growth. The term “imperiled” is more commonly referred to as “endangered” and it signifies a species that could become extinct – i.e. completely die out on the planet.
Once a species is put on the federal list it doesn’t mean that it will stay on there forever. A conservationist’s ultimate goal might be to restore a species and its habitat to such an extent that the species is no longer endangered or threatened. When that occurs the species is de-listed and loses some of the protections afforded to it by the Endangered Species Act (ESA). The bald eagle and gray wolf are examples of animals that were once on the brink of extinction, but thanks to conservation efforts, bans on hunting and pesticide laws, are now rebounding enough. Species can also be “downlisted,” meaning that the threats against them have lessened, so they go from a status of endangered to threatened.
While every state must obey the federal rules that apply to animals under the ESA states can also have their own versions of ESAs that cover other plants and animals. California, for example, has their own ESA – the most comprehensive of all state acts (it’s modeled after the federal act). Any threatened or endangered species in the state is protected under those regulations. Their Department of Fish and Game works with developers, land owners and others to try to lessen the negative impacts of shopping mall, housing development, road construction, etc. on the listed species.
My home state of Pennsylvania, on the other hand, does not have its own ESA. There are “jurisdictional agencies,” however, that can create their own regulations protecting threatened and endangered species from harm. The Pa. Fish and Boat Commission, as an example, has a list of protected reptiles, amphibians and fish – if the Commission catches someone hunting, trapping or otherwise harming these species they will be fined and/or put in jail. The same goes for mammals and birds. Unfortunately there is no state list of protected plants and insects in Pa. If a developer wanted to build an industrial park on a field of endangered sedge, they could do so with no penalty or required mitigation. State agencies still try to work with the developer to prevent this from happening but there are no legal “teeth” to it – it can only be a suggestion, not a requirement.
Extinction is forever; you might have heard that phrase before. While the statement is generally true, sometimes you hear of a supposedly extinct species, but then a few individuals are found, out of the blue. The indri, a large lemur on the island of Madagascar, is one such species, as is the ivory-billed woodpecker, which some people claim to have seen in recent years in Arkansas. I like to hope that there are enough pockets of good habitat in the world, away from the hands of man, where these so-called extinct species can continue to live on. Sadly some species are truly extinct… the dodo bird and passenger pigeon are two well-known examples. We can’t get those creatures back unless cloning on a Jurassic Park scale ever takes place.
When you hear the word “extinct,” it typically applies on a global scale, but some species are locally-extinct (meaning that they have disappeared in a given area but more may survive elsewhere). This is also referred to as “extirpation.” Then there are the species that are “extinct in the wild,” meaning that the only remaining individuals of a species are in captivity, like the Hawaiian crow, Scimitar Oryx and Barbary lion. Zoos may do captive breeding to increase the population with the hope of releasing some back into the wild, but that won’t be possible for every species. Some have no habitat to go back to, like the red-tailed black shark. This small freshwater fish, common in the aquarium trade (I had 2 growing up!), is extinct in the wild. Dams on rivers in Thailand are the main blame for the species’ extinction, and unless someone removes the dams, there is little change the fish could ever be reintroduced.
When you get down to it, this terminology encompasses the breadth of species out there, our impacts (both positive and negative) on them, and the need to conserve what we can. For as John Muir, one of the fathers of the conservation movement, once said, “When we try to pick out anything by itself, we find it hitched to everything else in the universe.” If we lose an endangered species to extinction, it may affect many other species as well.