Action Alerts

In this corner, weighing five ounces and standing 24 inches tall is the Giant Palouse Earthworm (Driloleirus americanus); and in the far corner stands the combined weight and resources of the U.S. Fish and Wildlife Service, the Department of the Interior, the Department of Justice, the Department of Agriculture, the Obama administration, the states of Idaho and Washington, and the resource extraction industries.

On June 30, 2009, the Friends of the Clearwater, the Center for Biological Diversity, the Palouse Prairie Foundation, the Palouse Audubon, and the Palouse Group of Sierra Club filed the second petition with the U.S. Fish and Wildlife Service (USFWS) requesting that they protect the giant Palouse earthworm as an endangered species. This native earthworm has been found only four times in the last 110 years, and continues to be threatened by agriculture, urban sprawl and invasive earthworms. All that you ever wanted to know about the giant Palouse earthworm can be found at the Palouse Prairie Foundation website, and if you have an interest in reading the complete petition, please see: http://palouseprairie.org/invertebrates/GiantPalouseEarthwormPetition200....

The first round of this Endangered Species Act petition was filed in August of 2006, soon after a University of Idaho researcher found the fourth specimen of the species in recorded history. This petition was denied by the Bush administration and this denial was upheld in court, under the pretence that substantial information was not provided in the petition to conclude that the species warranted protection. Ironically, that petition presented and summarized all the available scientific literature. The actual rarity of the native worm was never an issue in the denial. In addition, we cited that all of the local, regional, national, and international agencies, organizations, and experts have documented their recommendations that the species receive protected status because of its small population size and the rarity of its habitat.

Not much is known about these mysterious and rare earthworms. The giant Palouse earthworm (Driloleirus americanus) is a native species found only in the Columbia River Drainages of eastern Washington and Northern Idaho. The currently available scientific information states that it is an endemic that utilizes grassland sites with good soil and native vegetation. Only four positive collections of this species have been made within the last 110 years. Yet, in 1897 it was considered abundant.

Three of these collections were made at sites within the Palouse bioregion, one between Moscow, Idaho and Pullman, Washington, one near Moscow Mountain, and the third at a Palouse prairie remnant called, Smoot Hill. A fourth specimen was discovered near Ellensberg, Washington. (It is interesting to note that the Moscow/Pullman collection site has been converted to a parking lot, the Moscow Mountain collection site has been logged, and the Ellensberg site has never been identified.) This represents the entire history of positively identified sightings for this animal in the last 110 years. Other collections have been made of native earthworm specimens, but these specimens were never able to be positively identified past the level of genus because of the destruction of critical parts of the specimens during the collection procedure. Also, the Palouse prairie, which comprises much of the earthworm’s presumed range, is considered one of the most endangered ecosystems in the U.S. with less than two percent remaining in a native state. On the positive side, the recent collection in 2005 indicates that the species is still extant.

Soon after our recent petition was filed, one of the authors of several documents cited in our petitions wrote a letter of support to the USFWS which added additional information to what is known about this native worm. Samuel James, of the Biodiversity Institute, University of Kansas, is the only earthworm taxonomist operating in the USA, and has extensive experience in biodiversity inventory of earthworms. His letter offers no doubt that Driloleirus americanus is in danger of extinction. He gives three reasons for this, and offers as supporting information that the species is not anecic, as previously thought, but rather is endogeic.

Space does not permit a full transcript of his interesting letter, but it is worth reading the full text.

In his letter of support he argues: “First, it is almost universally true that earthworms are highly sensitive to habitat disturbance, which is to say that when the habitat is altered drastically and suddenly, such as is the case in forest clear cutting, or conversion of any habitat to agriculture by way of plowing and annual cultivation, the indigenous earthworms are generally destroyed.”

Second, “In the present case, invasive species pose a potential threat to the native D. americanus, something that any reasonable person would conclude, based on the scientific evidence available for other native earthworm species encountering invasions.”

“Third, a reasonable and sufficient effort has been made to find Driloleirus americanus in a variety of habitats within its presumed range. These efforts have failed except in very rare instances, and all of those have been in natural or little-disturbed vegetation… At the right time of year, anyone competent with a spade and able to dig several 30-40 cm deep holes should be able to find this worm if it is present. Even a low population density probably maintains upwards of 5 individuals per square meter.”

And, his bombshell, that the species is not anecic, as previously thought:

“In some of my work referred to in the petition, I speculated that Driloleirus americanus is an anecic species. Now that I have seen one, and learned more about the genus, my evaluation has changed. Driloleirus americanus is not the same ecologically as the anecic L. terrestris (editor’s note-an invasive Euro-Asian worm species also known as the nightcrawler). Driloleirus americanus is pale, indicating a life spent entirely below ground, unlike the surface feeding, pigmented L. terrestris. Michael Westwind, as quoted by Jodi Johnson-Maynard, the advisor of Yaniria Sanchez de Leon, reported that D. americanus does not make surface castings. The specimen I saw was pale- totally unpigmented, like the other Driloleirus species I have seen. If it does not defecate at the surface, and lacks pigmentation in the head, then it is highly unlikely to have the anecic lifestyle, which means feeding on surface plant remains. I have found other anecics very easily because they make a conspicuous heap of castings and vegetation remnants around the burrow openings… So it is probably an endogeic, meaning living entirely in the soil, on soil resources consisting of organic matter in varying stages of decomposition. This re-evaluation is significant to the petition to list D. americanus, because a large endogeic species is probably more susceptible to habitat changes than an anecic. In the conversion to agriculture, a grassland soil in the central USA will typically lose at least half of its organic matter during several years following initial plowing. Fertilizers and exposure to air accelerate the organic matter loss, and annual crops typically put a small fraction of their total net primary production into root mass. By contrast the perennial grasses of prairies put 50% more or less of their total annual production into the roots, which means a very large resource base for soil invertebrates living on the root exudates and root detritus food chain. After a long time-I am not sure how long, maybe 10 years?- the soil organic matter stabilizes at a low level, with only the lowest quality and most resistant organic matter remaining. For an anecic worm this is not such a problem, as long as there is surface litter to eat, and L. terrestris can and does survive in corn agriculture in the midwest, subject to the toxins applied by the farmers. The point is they can survive on crop leaf litter and other surface "trash". An endogeic will only get the depleted and low quality soil organic matter, anything left behind or defecated by any resident anecics, and anything turned under by plowing. If the soil organic matter dynamics of Palouse Prairie are similar to central US tallgrass prairie, then Driloleirus could be starved out of wheat fields, even if it could survive the mechanical disturbances, chemicals, etc… Another difference to the petition concerns the ease with which one may catch endogeic worms compared to anecics. We have already seen that Fauci et al. were able to catch the famously fast anecic L. terrestris by digging. Endogeic worms typically do not move with great speed. I was able to dig out some 50-70 cm Diplocardia biprostatica in dense clay in Oklahoma, in spite of the fact that the worms had many months, or years (I maintained one adult specimen for two years after capture, indicating a long life span), to prepare their burrow escape route and I was going in with a spade over a course of several minutes. It was very hard to dig fast in that clay, but I got the worms. Thus I am confident in Fauci's ability to dig up D. americanus. We need not attach much practical significance to the reports of 2+ meter-deep burrows created by this D. americanus. However, I doubt very much that the species will retreat into the burrows except to escape drought, because their feeding is entirely below ground, meaning that they defecate into their burrows, effectively blocking the retreat. Most of the worm food in a grassland soil is within the top 20 cm, well within digging range. They could range deeper, but Fauci et al. were on the lookout, so I believe that their failure to find is more probably due to absence of worms rather than faulty or inadequate effort… I am confident of my conclusions and recommendations given the information presently available to me, which I believe is complete and not overlooking important data. The listing of this species as endangered will bring long-overdue attention to the fact that it is not only popular, charismatic organisms that are in danger of extinction. I also do not accept that such a listing will pose any threat to the ability of people to responsibly use their property. As we have noted, 99% of the potential damage to the Palouse is already done. The preservation of this species should be compatible with sustainable land use, sustainable livestock grazing pressure, and recreation. Preservation will have collateral benefits, not least the protection of habitat in which other, even more inconspicuous life forms continue to survive.” For the full text see: http://www.friendsoftheclearwater.org/sites/default/files/James letter of support text.doc

With the submission of this second petition, the USFWS is required to make an initial finding within 90 days as to whether or not the petition presents substantial information indicating that the listing is warranted. So we should hear from them again by the end of September.

Stay tuned.