Why Protect Endangered Invertebrates?

The Xerces blue butterfly, Oahu treesnail, Antioch katydid, Stone Mountain Fairy Shrimp, Tobias' caddisfly, Tennessee riffleshell mussel, Colorado burrowing mayfly, Rocky Mountain grasshopper. All of these species have two things in common: they all are invertebrates, and they all were driven extinct by humans.

Invertebrates-butterflies, beetles, bees, ants, dragonflies, spiders, snails, lobsters, and starfish, to name but a few-are at the heart of a healthy environment, vital to life as we know it. They build the stunning coral reefs of our oceans, give color to vibrant fields of springtime wildflowers, and serve as food for countless other animals.

Many people understand that invertebrates, in general, are highly important to our lives. But what about endangered invertebrates? What is the importance of protecting the Manus Island tree snail from extinction? Why protect the Government Canyon cave spider? What good are they? Does it really matter if a few of these invertebrates goes extinct?

Individually, endangered invertebrates are unlikely to determine the fate of a large ecological system, but as a group they can have quite a large effect. These endangered animals often perform unique ecosystem functions, such as feeding on particular kinds of wood, dung, or carrion. Endangered species also can play a linchpin role in small, specialized systems, such as caves, oceanic islands, or some pollinator-plant relationships. For example, many plant species, like Arizona's Bear claw poppy (Arctomecon humilis), rely solely on one or just a few pollinators. Decreased abundance or the loss of such pollinators would have dramatic negative consequences on these plant populations. Finally, endangered invertebrates are often important indicators of the loss of unique ecosystems: butterflies and prairies in the Pacific Northwest, snails and old growth forest in the Black Hills, and mussels and clear creek waters in the mountains of Appalachia, important components of our natural heritage.

Though they are indisputably the most important creatures on earth, invertebrates are an overlooked segment of our ecosystems. Many people can identify an endangered Bengal tiger, but few can identify an endangered Salt Creek tiger beetle. The Endangered Species Act has always treated vertebrates more generously than it does invertebrates. Whereas the ESA authorizes the protection of "distinct population segments" of vertebrates, only species and subspecies of invertebrates may be protected. This provision was a compromise between the House and the Senate in 1978 after the House voted to eliminate protection for invertebrates altogether. Moreover, unlike the success stories of the American alligator and the brown pelican, no insect has been taken off the ESA list.

The U.S. Fish and Wildlife Service (USFWS) lists 44 insects as either endangered or threatened. Do these figures on endangered insect species reflect a realistic estimate as to the number of species at risk? No. While insects make up more than 72% of global animal diversity, only 4% of the endangered animal species listed by the USFWS are insects. By comparison, of all the vertebrates described in the U.S., 17.9% are listed as threatened or endangered. So, assuming that insects and vertebrates face similar destructive forces at similar levels of intensity, we would expect to find not 44 but on the order of 29,000 at-risk insects in the U.S. alone. Although this assumption oversimplifies the situation, it is clear that the ESA list is a gross underestimate of endangered and threatened insects, let alone other invertebrates.

Why the disparity? True, wolves are more charismatic than flies. Wolves have had active advocates for many years whereas flies and other less recognized invertebrates have few advocates. Do charismatic organisms receive protection simply because they are appealing? Or, have the taxonomy, distribution information and decline of these charismatic animals been studied to such an extent that we know which need protection, while we are less clear about the situation with invertebrates? Or are these two phenomena tied together? It's hard to tell. We do know that conservationists and agencies need to do much more to conserve the less charismatic, but still vitally important pieces of our ecosystem puzzle.

The number of endangered invertebrates is large and growing. The current rate of destruction and degradation of natural habitats is so great that there are not nearly enough biologists to even catalog, much less study, the species suddenly on the edge of extinction. Now is the time for agencies, scientists, conservationists, and land managers to promote the conservation of imperiled insects.

Although Aldo Leopold was not an entomologist he summed it up well in his book Round River:

"If the land mechanism as a whole is good, then every part is good, whether we understand it or not. If the biota, in the course of eons, has built something we like but do not understand, then who but a fool would discard seemingly useless parts? To keep every cog and wheel is the first precaution of intelligent tinkering."

Protecting some of the smallest pieces of the land mechanism. That is what the Xerces Society has tried to do for 30 years and what we will continue to pursue in the years ahead.