SPECIES FACT SHEETScientific Name: Driloleirus macelfreshi (Smith 1937)Common Name(s): Oregon Giant EarthwormPhylum: AnnelidaClass: ClitellataOrder: Opisthopora Suborder: Crassiclitellata Family: Megascolecidae(ITIS 2017)

Synonyms: Megascolides macelfreshi (NatureServe 2017)Conservation Status:

Global Status: G1 (last reviewed 20 February 1989)National Status (United States): N1 (06 February 2006)State Statuses: S1 (OR)(NatureServe 2017)Federal Status (United States): SOC (ORBIC 2016)IUCN Red List: EN (IUCN 2017)

Taxonomic Note:

This species was originally placed in the genus Megascolides; however, after further assessment of this and five other North American species, it was moved to Driloleirus (Fender and McKey-Fender 1990; Applegarth 1995). Technical Description:

Adult: Species in the family Megascolecidae are difficult to identify; specimens must be dissected to identify genus and expert knowledge of earthworm anatomy is needed to identify to species (FOC et al. 2009). Driloleirus macelfreshi is one of the largest North American earthworms (Wells et al. 1983). It is distinguished by its characteristic large size (up to 1.32 m in length and between .5 and 1 cm in diameter), pale whitish color, and distinctive, floral (lily-like) odor (Fender 2009, pers. comm.). The clitellum of this species (a swelling of the body towards the head of the worm where the gonads are located) extends from segments 13 to about 22, and there are numerous nephridia (networks of tubules that have an excretory function) on each body segment (Wells et al. 1983).

Fresh (refrigerated) specimens are best for identification (Fender 2009, pers. comm.). There are currently no keys to megascolecid worms in this region

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(Applegarth 1995), although a complete, technical description can be found in Smith (1937). Dissection and genetic work is recommended for species level identification (USFWS 2011; Rosenberg 2018, pers. comm.).

Immature: Juvenile earthworms are difficult to identify and sexually-mature earthworms (at least 3 to 6 months) are needed to identify specimens to the Driloleirus genus (USFWS 2011). Since immature specimens of this species are not as large and because there are other large, white, fragrant earthworms in the Willamette Valley that could be mistaken for this taxon, specimen collection and expert identification based on internal anatomy is essential for this species. Eggs and larvae of this species have not been described, but the eggs of other Driloleirus species are described as very irregularly fusiform, meaning they are rumpled in appearance, very irregular, and not at all lemon-shaped (Fender 2009, pers. comm.). According to William Fender (2009, pers. comm.), “if you cut a leg off a pair of pants, stuffed it not quite full of dough, tied off the ends, and then pushed in the sides at random places you would get something similar.”

Life History:

Adults: Most species of earthworms native to the Pacific Northwest likely reproduce in the winter and early spring months and spend much of the summer in aestivation (Fender and McKey-Fender 1990). Three main life history strategies have been identified for earthworms, characterized by the species’ distribution within the soil profile: epigeic, endogeic, and anecic. The biologically and ecologically similar species, D. americanus, has been identified as both endogeic (occurring within the upper mineral horizons and feeding on decomposing organic matter) and anecic (forming burrows spanning soil horizons and feeding on less-decomposed organic matter near or at the surface (Edwards and Bohlen 1996; USFWS 2011; Blevins 2016). Although observed activity generally takes place near the surface, it is believed that D. macelfreshi constructs permanent subsurface burrows as deep as 4.6 m (15 ft.), a depth approximation based on one road cut where burrows were found (Wells et al. 1983; Fender 1995).

The life history of this species is not well understood and is based on a very limited number of specimens (Rosenberg 2009, pers. comm.). Like other Driloleirus, it is believed to feed on organic matter, including mosses, decaying conifer needles, bits of wood, grass seeds and stems, and an occasional dead insect (Smith 1937). Wells et al. (1983) states that D.

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macelfreshi feeds on pure organic residues, with only a slight mixture of soil. In response to disturbance, this worm produces a saliva with a flowery (lily-like) odor that is hypothesized to be a type of chemical defense (Fender 1995). Maximum cocoon production is during late winter and early spring (NatureServe 2017).

Range, Distribution, and Abundance:

Type Locality: Salem, Oregon in January 1903 (Smith 1937).Range: Megascolecid earthworms in the Pacific Northwest are found in forested areas and their current range is limited by arid lands to the east and south (Applegarth 1995). Driloleirus macelfreshi is endemic to Oregon and found in the Coast Range and Willamette Valley ecoregions (ORBIC 2016).

Distribution: This species is native to the Columbia River basin and has been detected in Benton, Clackamas, Lincoln, Linn, Marion, Polk, Yamhill Counties (ORBIC 2016) and most recently Lane County in Oregon (BLM 2017; NatureServe 2017).

BLM/Forest Service Land:

Documented: This species has not been documented on BLM or Forest Service land.

Suspected: This species is suspected to occur on BLM land in the Northwest Oregon BLM District (in Benton and Lane Counties). Roseburg BLM District personnel also consider the species to be suspected.

Abundance: Due to the difficulty in detecting D. macelfreshi, abundance estimates are not available; however, this species does appear to be rare (FOC et al. 2009). The current sampling method of hand sorting may underestimate the species’ abundance; additionally, its distribution and abundance may be patchy and seasonally variable.

Habitat Associations:

Similar to Oregon’s other indigenous worms, this species appears to have a narrow range of tolerance for soil conditions, favoring fine textured soils rich in clay (Fender 1995). It has been suggested that it prefers well drained soils (fine-grained, clay to silt loams) that are near subsurface water, often where the water table is reachable but the soil is not waterlogged. It is associated

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with deep, little disturbed soils in moist mixed forest of Douglas fir (Pseudotsuga menziesii), grand fir (Abies grandis), and bigleaf maple (Acer macrophyllum) and is also known from pure Douglas-fir woodlots and occasionally from oak-ash woods (Wells et al. 1983). However, a 2008 sighting occurred in a relatively disturbed urban park near the Willamette River, adjacent to a dense cover of Armenian blackberry in an otherwise mixed hardwood riparian zone (Gervais 2008; Rosenberg 2009, pers. comm.). It is apparently tolerant of the acidic soil found under coniferous forests.

This species is likely found in suitable habitat on valley floors at elevations between 40-150 meters (Blakemore 2014; Fender 2018, pers. comm.). The five historic sites re-sampled in 2000 by Bailey et al. (2002) were at approximately 70 m elevation, and were adjacent to farmland, rivers, creeks, ponds, or sloughs. Presently, the dominant overstory at these historic sites consists of Douglas-fir, bigleaf maple, Oregon white oak (Quercus garryana), red alder (Alnus rubra), and Oregon ash (Fraxinus latifolia) and the understory consists of English ivy (Hedera helix), Armenian blackberry (Rubus armeniacus), dull Oregon grape (Mahonia nervosa), Pacific blackberry (Rubus ursinus), snowberry (Symphoricarpos albus), and western sword fern (Polystichum munitum) (Bailey et al. 2002).

Threats:

Given how little is known about the life history of this species, assessment of threats is difficult (Rosenberg 2009, pers. comm.). Habitat loss and the establishment of introduced earthworms are currently identified as the two major threats to this species (Fender 2009, pers. comm.). In the Willamette Valley, less than one percent of the original estimated acres of pre-European settlement grasslands remains (USFWS 2000) and conversion of land for agriculture, industry, or urban/suburban development has eliminated much of this species’ suitable habitat (Wells et al. 1983). Such conversions result in drastically altered or lowered food resources for all worms, and favor the exotic Lumbricidae species (Wells et al. 1983). In places where habitat remains, heavy chemical treatment for agricultural or forest management purposes may pose threats to this species (Wells et al. 1983). Non-native earthworms of the Lumbricidae family not only compete for resources with native species, but also raise the pH of the soil, lessening its suitability for native species that tend to thrive in more acidic soils (Bailey et al. 2002). It must be stressed, however, that the status and threats of this species cannot

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be fully assessed until an effective survey protocol is developed and tested (Rosenberg 2009, pers. comm.). Suitable habitat does not likely exist at multiple historic sites; in particular Clackamas, Marion, and Polk Counties are densely populated.

Additional threats to earthworm populations include herbicides, insecticides, and fungicides applied in agricultural production (FOC et al. 2009). The changes in weather caused by climate change will likely have a negative impact on D. macelfreshi populations (similar to the effects predicted for D. americanus’ habitat), as annual precipitation is a parameter of its habitat (FOC et al. 2009).

Threats that have been proposed to impact the closely related D. americanus and may have similar impacts to D. macelfreshi include habitat loss and fragmentation, general impacts to soil characteristics (disturbance, pesticide use, and soil microclimate), soil compaction, alteration of soil chemistry, tillage and agriculture, grazing, urban and rural development, and forest management (FOC et al. 2009; Blevins 2016).

Conservation Considerations:

Research: There are over 56 unnamed megascolecid worms in this region and very little literature on how to distinguish even the named species. A taxonomic key for Oregon native earthworms is in serious need of development (Applegarth 1995; Fender 2009, pers. comm.). Genetic research could assist with the study of systematics of the argilophiline earthworms of the Pacific Northwest. Genetic analyses on current and future collections would be beneficial, since this species can be difficult to identify (Rosenberg 2018, pers. comm.).

Ongoing genetic research to develop non-lethal species identification will likely reduce impacts from more intensive survey efforts for D. americanus (Blevins 2016); similar efforts could benefit D. macelfreshi research. Species identification methods have typically required specimen preservation and dissection, but genetic data is currently being used to develop environmental DNA (eDNA) sampling techniques (Johnson-Maynard and Baugher 2015; Baugher 2016, pers. comm.). Utilizing survey techniques such as eDNA may prove to be a fruitful sampling approach for this species. Collection of casts or burrow scrapes may be useful for species detection in the future, and is

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considered preferable to whole animal collection as it is nondestructive and noninvasive (Johnson-Maynard and Baugher 2015).

Habitat requirements are not well understood, and specifics of habitat type associated with this species are limited. Research targeted to assess the distribution, habitat diversity, biology, and population trends of D. macelfreshi populations is needed to conduct a credible scientific assessment of potential threats to the species and to understand the effects of habitat loss, conversion, or fragmentation. Additional research in these areas, as well as evaluation of threats to the species, would provide valuable information that could inform conservation efforts.

Rosenberg (2009) suggests the possibility of training dogs to sniff out specimens occurring on the surface after heavy rain to improve the survey protocol for this species. Working Dogs for Conservation is a non-profit organization actively employing canine-human teams for wildlife censusing, monitoring, and research (WD4C 2009).

Inventory: Surveys are needed to determine the current range and habitat preferences for D. macelfreshi. Suitable habitat on BLM land in the Northwest Oregon District (in Benton and Lane Counties), near recent records from 2008, in Benton County, and 2009, in Lane County, could be surveyed; additional populations of D. macelfreshi from Benton County are plausible (Fender 2018, pers. comm.). Revisiting and surveying areas near historic records (pre-1985) could help determine the current range of this species. Additional efforts to evaluate and improve survey methods, including both increasing effectiveness and reducing destructiveness, could be included in future surveys (Blevins 2016).

Management: Management actions will be best informed by the additional research and inventory considerations discussed above. In the meantime, minimize disturbance in areas where this species is known or suspected, as equipment can introduce and favor exotic earthworms. Educate land owners and managers about this species and its status and conservation needs on their lands (Rosenberg 2009). D. macelfreshi will likely benefit from minimal management seen in riparian reserves, where soil and canopy conditions are minimally disturbed (Applegarth 1995). In one study, spring burns caused a substantial decline in earthworm populations (Neumann and Tolhurst 1991 in Applegarth 1995); consider burning in the fall to reduce negative impacts to

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earthworms if prescribed burns are part of management activities at occupied sites.

Little is known about this species’ distribution or current threats to populations; however, based on potential threats to D. americanus (discussed in FOC et al. 2009; USFWS 2011; Blevins 2016), the following general recommendations are provided:

Limit land management activities that disturb soils or have the potential to impact soil microclimate, such as those that create bare soil or reduce surface litter or affect soil temperature and moisture.

Avoid tillage, pesticide application, and heavy grazing or trampling of potential D. macelfreshi habitats.

Maintain existing Douglas fir forest remnants or other undisturbed habitats within the species’ known range.

Version 3: Prepared by: Katie Hietala-HenschellThe Xerces Society for Invertebrate ConservationDate: June 2018

Reviewed by: Candace FallonThe Xerces Society for Invertebrate ConservationDate: June 2018

Version 2: Prepared by: Sarah Foltz JordanThe Xerces Society for Invertebrate ConservationDate: June 2009

Reviewed by: Dan Rosenberg and William FenderOregon State University and Oregon Wildlife Institute Date: August 2009

Version 1: Prepared by: Scott Hoffman Black and Logan LauvrayThe Xerces Society for Invertebrate ConservationDate: September 2005ATTACHMENTS:

(1)References (2)List of pertinent or knowledgeable contacts (3)Map of known records in Oregon

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(4)Photographs of closely related species(5)Survey protocol, including specifics for this species

ATTACHMENT 1: References

Applegarth, J.S. 1995. Invertebrates of special status or special concern in the Eugene district. U.S. Department of the Interior, Bureau of Land Management. Eugene, OR. 126 pp.

Bailey, D.E., D.K. Rosenberg, W. Fender, D. McKey-Fender, and J. Jacobs. 2002. Patterns of abundance and habitat associations of earthworms in remnant forests of the Willamette Valley, Oregon. Northwest Science. 76(1):26-34.

Blakemore, R. 2014. Driloleirus macelfreshi. The IUCN Red List of Threatened Species 2014: e.T6829A21416138. http://dx.doi.org/10.2305/IUCN.UK.2014-1.RLTS.T6829A21416138.en. Downloaded on 18 April 2018.

Blevins, E. 2016. Species Fact Sheet. Giant Palouse Earthworm (Driloleirus americanus). 15p. Available at: https://www.fs.fed.us/r6/sfpnw/issssp/species-index/fauna-invertebrates.shtml[FOC et al.] Friends of the Clearwater, Center for Biological Diversity, Palouse Audubon, Palouse Prairie Foundation, and Palouse Group of the Sierra Club. 2009. Petition to List the Giant Palouse Earthworm (Driloleirus americanus) as a threatened or endangered species under the Endangered Species Act. 25 p.

Fender, W.M. 1995. Native Earthworms of the Pacific Northwest: An Ecological Overview. In: Hendrix, Paul F. (ed.) Earthworm Ecology and Biogeography in North America. CRC Press, Boca Raton, Florida.

Fender, W.M. 2009. Personal communication with Sarah Foltz Jordan, the Xerces Society. William Fender, Independent Consultant, Portland, OR, 97205.

Fender, W.M. 2018. Personal communication with Katie Hietala-Henschell, the Xerces Society. William Fender, Independent Consultant, Portland, OR, 97205. May 2, 3, 10, and 14.

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Fender, W.M. and D. McKey-Fender. 1990. Oligochaeta: Megascolecidae and Other Earthworms from Western North America. p. 357-378. In: Dindal, Daniel L. (ed.) Soil Biology Guide. Wiley and Sons, New York, New York.

Gervais, J. 2008. Details of “Rediscovery” of Oregon Giant Earthworm in 2008. Unpublished report. Further details can be obtained by contacting: Dr. Jennifer Gervais, Oregon Wildlife Institute.

[ITIS] Integrated Taxonomic Information System. 2017. Driloleirus macelfreshi [web application]. Available at: https://www.itis.gov (Accessed: 30 March 2018).

[IUCN] International Union for Conservation of Nature. 2017. The IUCN red list of threatened species. [web application]. Available at http://www.iucnredlist.org/search (Accessed: 30 March 2018).

NatureServe. 2017. Driloleirus macelfreshi NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://explorer.natureserve.org (Accessed: 30 March 2018).

[ORBIC] Oregon Biodiversity Information Center. 2016. Rare, threatened and endangered species of Oregon. Institute for Natural Resources, Portland State University, Portland, Oregon. 130 pp. Available at http://inr.oregonstate.edu/sites/inr.oregonstate.edu/files/2016-rte-book.pdf

Rosenberg, D. 2009. Personal communication with Sarah Foltz-Jordan, the Xerces Society. Dan Rosenburg, Oregon State University and Oregon Wildlife Institute, Corvallis, OR 97331. March 27.

Rosenberg, D. 2018. Personal communication with Katie Hietala-Henschell, the Xerces Society. Dan Rosenburg, Oregon State University and Oregon Wildlife Institute, Corvallis, OR, 97331. May 1, 2, 4, 7, 10.

Smith, F. 1937. New North American species of earthworms of the family Megascolecidae. United States National Museum, Proceedings, Volume 84, pages 157-181. [Driloleirus macelfreshi, as Megascolides macelfreshi, is named on pages 166-168. This publication is in the University of Oregon science library under Q11.U55.]

[USFWS] United States Fish and Wildlife Service. 2000. Endangered and threatened wildlife and plants; endangered status for Erigeron decumbens

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var. decumbens (Willamette daisy) and Fender’s blue butterfly (Icaricia icarioides fenderi) and threatened status for Lupinus sulphureus ssp. kincaidii (Kincaid’s lupine). 50 CFR Part 17. 65(16): 3875-3890.

[USFWS] United States Fish and Wildlife Service. 2011. Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To List the Giant Palouse Earthworm (Driloleirus americanus) as Threatened or Endangered. Federal Register 76(143):44547-44564.

Wells, S.M., P.M. Pyle, and N.M. Collins, N.M. 1983. The IUCN Invertebrate Red Data Book. IUCN, Gland, Switzerland. 632 pp.

[WD4C] Working Dogs for Conservation. 2015. Projects. Bozeman, MT 59771. [website] Available at: http://www.workingdogsforconservation.org/ (Last accessed June 2018).

Map references:

[BLM] Bureau of Land Management. 2017. GeoBOB GIS export provided to Candace Fallon, the Xerces Society, by Chelsea Waddell, BLM Regional GeoBOB and ARIMS Data Coordinator, October 2017.

Fender, W. 2009. Personal species record database provided to Sarah Foltz Jordan, the Xerces Society, by William Fender, Independent Consultant, 2009.

Gervais, J. 2009. Details of “Rediscovery” or Oregon Giant Earthworm in 2008. Unpublished Report.

Wells, S., R.M. Pyle, and M.N. Collins. 1983. The IUCN Invertebrate Red Data Book. IUCN, Gland Switzerland. 632 pp.

Roseburg, D.K. 2009. Historic records provided to Sarah Foltz Jordan, the Xerces Society by Dan Roseburg, Oregon State University, Corvallis, OR.

ATTACHMENT 2: List of pertinent, knowledgeable contacts

Dan Rosenberg, Oregon State University and Oregon Wildlife Institute, Corvallis, OR, 97331.

Michael Westwind (William Fender), Independent Consultant, Portland, OR, 97205.

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ATTACHMENT 3: Map of known Driloleirus macelfreshi records in Oregon

Known and suspected records of Driloleirus macelfreshi in Oregon, relative to Forest Service and BLM land. Note: Red represents current records (2008 to the present), black represents historic records or records documented before

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1985, and blue represents suspected records in need of ID. No D. macelfreshi records are available from 1986 through 2007.

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ATTACHMENT 4: Photograph of closely related species

Photo of Driloleirus americanus. D. americanus is a similar species in the same genus as D. macelfreshi. Adult Driloleirus spp. are distinct; however, identification to the species level requires dissection or genetic analysis. © Chris Baugher. Image licensed under Creative Commons (http://creativecommons.org/licenses/by-nc/2.0/), which permits one to “Share — copy and redistribute the material in any medium or format.” Image and licensing information available online: http://eol.org/data_objects/31735403.

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ATTACHMENT 5: Survey Protocol

Originally Prepared by: Sarah Foltz Jordan, the Xerces SocietyDate: June 2009 Update: December 2010

Edited by: Dan Rosenberg (Oregon State University and Oregon Wildlife Institute) and William FenderDate: August 2009

Updated: Emilie Blevins and Katie Hietala-Henschell, the Xerces Society Date: May 2018

Survey Protocol:

Taxonomic group:

Oligochaete

Where: Surveys should take place at appropriate habitat within the known range of the target species. Indigenous worms in the Pacific Northwest typically have a narrow range of tolerance for soil conditions, favoring fine textured soils rich in clay (Fender 1995). Native (megascolecid) earthworms seem to be more tolerant of the acidic soils of coniferous forests (Applegarth 1995). It has been suggested that it prefers well drained soils (fine-grained, clay to silt loams) that are near subsurface water, often where the water table is reachable but the soil is not waterlogged. This species is associated with deep, little disturbed soils in moist mixed forest of firs and bigleaf maples and is also known from pure Douglas-fir woodlots and occasionally from oak-ash woods (Wells et al. 1983). When surveying for specimens or visiting potential sites, detailed habitat data should be acquired, including soil type, drainage, land-cover, and overstory and understory vegetation.

When: Sampling is recommended between February and April, when soils are moist and above freezing (Bailey et al. 2002). Surveys are most promising in foggy, drippy weather after rain (Fender 2009, pers. comm.).

How to Survey: There is not a well-established survey protocol for Oligochaete. Searching for worms on the surface after a long-term, saturating rain is currently thought to be more efficient than digging for

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them, although this method is also unlikely to be very fruitful (Rosenburg 2009, pers. comm.). The standard way includes digging and sorting through the excavated dirt by hand, and consists of digging quickly and deeply as earthworms retreat downward in response to disturbance (Applegarth 1995).

Hand sorting consists of removing a volume of soil from a collection plot, which varies in dimension depending on the species and soil profile of interest. Soil is removed using a tool such as a spade or trowel, metal corer, or plastic PVC collar. Sorting can be conducted in any soil type, but soils should be examined one layer at a time, and layers should not be mixed. Soil can be transferred to a plastic sheet from which it is hand sorted, soil clods are broken up, and earthworms are sieved. Once examined, soil can be deposited on a light-colored tray or container. Soil should be returned in the same order and layer as it was extracted. Water can also be used when sieving to increase efficiency (Clapperton et al. 2007). Note, however, that hand sorting is considered destructive, as large soil pits (30cm x 30 cm x 50cm deep, Xu et al. 2013; 60cm x 60 cm, USFWS 2011) are dug, and soil is sieved to extract earthworms.

A potentially promising survey technique involves the use of detector dogs to seek out worms, both living and dead, based on scent (Rosenberg 2009, pers. comm., Fender 2009, pers. comm.). Working Dogs for Conservation is a non-profit organization actively employing canine-human teams for wildlife censusing, monitoring, and research (WD4C 2015). Pigs may also prove to be a viable method for worm detection, as they naturally know how to catch worms quite effectively, and can be trained to respond to certain scents (James 2010, pers. comm.).

Xu et al. (2013) tested several methods, including electroshocking with soil probes, which was used to successfully collect specimens of D. americanus, although the authors noted that efficacy of electroshocking may be influenced by soil moisture and conductivity. Electroshocking can be conducted by placing soil probes within a sampling area of a chosen size and applying an alternating current (Xu et al. 2013 applied 200V) to probes in cycles of 1 minute. Weyers et al. (2008) describe a design for building and operating an electroshocking device for earthworm sampling. A combination of electroshocking and hand sorting the top 10 cm of soil is recommended when soil moisture is low (below 20%) or to reduce disturbance (Xu et al. 2013). Xu et al. (2013) did not successfully collect specimens when testing

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application of allyl isothiocyanate (AITC) to the soil, one type of chemical irritant that can cause earthworms to move to the soil surface (Clapperton et al. 2007).

Since worms often contract and become short and turgid upon disturbance, it is important to take length and diameter measurements of collected worms as soon as possible. Ideally, it is best to transport collected specimens alive (in soil in a cooler) to an expert for preservation and identification, since the relaxation and preservation process of this species involves chemicals that may not be readily available. If uninjured, collected worms can be kept alive in refrigerated conditions for a few days. If live transportation to an expert is not possible, the best preservation method is as follows (Fender 2009, pers. comm.). First, slowly anesthetize the worm by putting it in a dish of water and slowly adding ethanol to the water. An Epsom salt solution can be used for the same purpose, but ethanol is better for large worms. Once the worm is relaxed, fix it with a formalin, ethanol, acetic acid mixture, such as Lavdowsky's mixture. Before fixing the worm, dipping it for a few seconds in Bouin's picro-formol is recommended (Fender 2009, pers. comm.), but that solution can be hard to obtain and is very dangerous if not cared for properly (James 2010, pers. comm.). After the worm has been in the Lavdowsky's mixture for several hours (or overnight), transfer it to 9:1 formalin or 70% ethanol, the former of which is preferred. The point of this procedure is that the anesthetization process leaves the worm relaxed and fully extended, which is better for anatomical study, and the mixture of ethanol, formalin and acetic acid penetrates quickly and fixes the tissues well (Fender 2009, pers. comm.). Just putting the worms in ethanol or formalin can leave large worms almost unusable because the internal tissues degrade before they are fixed (Fender 2009, pers. comm.). Separate collection and preservation of tissue samples for genetics work (DNA barcoding) is also recommended and may enable the future identification of juveniles, fragments and egg capsules (James 2010, pers. comm., Rosenberg 2009, pers. comm.). When preserving for DNA, place tissue sample (at least 3 mm by 3 mm) in the strongest alcohol possible (90% or higher) (James 2010, pers. comm.).

Species identification methods have typically required specimen preservation and dissection, but genetic data is currently being used to develop environmental DNA (eDNA) sampling techniques (Johnson-Maynard and Baugher 2015; Baugher 2016, pers. comm.). Collection of casts or

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burrow scrapes may be useful for species detection in the future, and is considered preferable to whole animal collection as it is nondestructive and noninvasive (Johnson-Maynard and Baugher 2015).

Species-Specific Survey Details:

Driloleirus macelfreshi

Where: This species’ habitat associations are not well understood; it is known from around 16 sites within Oregon’s Willamette Valley and Coast Range, with records from Lincoln, Linn, Marion, Polk and Yamhill counties and, more recently (2008), Benton County and Lane County (2009, 2015). Surveys for this species should take place at appropriate habitat within the known range of this species, although it is stressed that both the habitat and range are based on somewhat limited information (Rosenberg 2009, pers. comm.). Like Oregon’s other indigenous worms, this species has a narrow range of tolerance for soil conditions, favoring fine textured soils rich in clay (Fender 1995). It has been suggested that it prefers well drained soils (fine-grained, clay to silt loams) that are near subsurface water, often where the water table is reachable but the soil is not waterlogged. This species is associated with deep, little disturbed soils in moist mixed forest of firs and bigleaf maples and is also known from pure Douglas-fir woodlots and occasionally from oak-ash woods (Wells et al. 1983). It is apparently tolerant of the acidic soil found under coniferous forests. The five historic sites re-sampled in 2000 by Bailey et al. (2002) were at approximately 70 m elevation, and were adjacent to farm-land, rivers, creeks, ponds, or sloughs. Presently, the dominant overstory at these historic sites consists of Douglas-fir, bigleaf maple, Oregon white oak, red alder and Oregon ash and the understory consists of English ivy, Armenian blackberry, dull Oregon grape, Pacific blackberry, snowberry, and western sword fern (Bailey et al. 2002). Despite the species’ presumed requirement for little disturbed soil, the 2008 sighting occurred in a relatively disturbed urban park near the Willamette River, adjacent to a dense cover of Armenian blackberry in an otherwise mixed hardwood riparian zone (Gervais 2008; Rosenberg 2009, pers. comm.). Survey efforts for this species, and other native earthworms, should target undisturbed forested areas, as worms along roads are likely exotics (Applegarth 1995).

When: Sampling is recommended between February and April, when soils are moist, temperatures are above freezing, and conditions are generally damp

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(Bailey et al. 2002). Surveys are most promising in foggy, drippy weather after rain (Fender 2009, pers. comm.). Wet fall weather or mid-springtime.

How: There is not a well-established survey protocol for this species, and many of the known records are from specimens that were encountered accidentally (Rosenberg 2009, pers. comm.). A protocol that proved unsuccessful at sampling this species involved excavating a 22 x 22 x 25 cm area below the surface at 45 or more different locations within each of five historic sites (Bailey et al. 2002). Successful surveys are difficult because the Oregon Giant Earthworm is apparently able to move rapidly through permanent subsurface burrows and may move deep into the ground when they sense the vibration of digging. The depth at which this species constructs permanent subsurface burrows (as deep as 4.6 m (15 ft.)) probably contributes to the scarcity of sightings (Wells et al. 1983, Fender 1995). Searching for worms on the surface after a long-term, saturating rain is currently thought to be more efficient than digging for them, although this method is also unlikely to be very fruitful (Rosenburg 2009, pers. comm.). A potentially promising new survey technique involves the use of detector dogs to seek out worms, both living and dead, based on scent (Rosenberg 2009, pers. comm., Fender 2009, pers. comm.). Working Dogs for Conservation is a non-profit organization actively employing canine-human teams for wildlife censusing, monitoring, and research (WD4C 2015). The use of detector dogs is an effective method of detection for dozens of species, including the threatened Kincaid’s lupine in Oregon, the Desert tortoise in Nevada, and the invasive rosy wolf snail in Hawaii (WDC 2009). Pigs may also prove to be a viable method for worm detection, as they naturally know how to catch worms quite effectively, and can be trained to respond to certain scents (James 2010, pers. comm.). Although no attempts have yet been made to investigate the feasibility of these survey methods for the Oregon giant earthworm, steps are being taken to prepare for their future possibility. For example, upon collection of the most recently encountered specimen (December 2008), a 1 cm segment of tissue was removed before chemical preservation and frozen for potential use as training scent (Gervais 2008).

Tentative, on-site identification of this worm is based on the characteristic large size (up to 1.32 m in length and between .5 and 1 cm in diameter), pale whitish color, and distinctive, floral (lily-like) odor. However, since young individuals of this species are not as large, and since there are many other

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large, white, fragrant earthworms in the Willamette Valley which could be mistaken for this taxon, specimen collection, expert examination, and genetic analysis is absolutely essential for definitive identification this species. William Fender is the foremost authority on the Oregon giant earthworm, and should be consulted regarding any collected or reported specimens. Although there are currently no keys to megascolecid worms in this region (Applegarth 1995), a complete, technical description can be found in Smith (1937).

References (survey protocol only):

Applegarth, J.S. 1995. Invertebrates of special status or special concern in the Eugene district. U.S. Department of the Interior, Bureau of Land Management. Eugene, OR. 126 pp.

Bailey, D.E., D.K. Rosenberg, W. Fender, D. McKey-Fender, and J. Jacobs. 2002. Patterns of abundance and habitat associations of earthworms in remnant forests of the Willamette Valley, Oregon. Northwest Science 76(1): 26-34. Baugher, C. 2016. Personal communication with Chris Baugher. Doctoral candidate, Department of Plant, Soil & Entomological Sciences, University of Idaho, 875 Perimeter Drive MS 2339, Moscow, ID 83844-2339. February 16, April 29, October 7. Clapperton, M.J., G.H. Baker, and C.A. Fox. 2007. Chapter 34: Earthworms. In: Carter, M.R. and E.G. Gregorich (eds) Soil Sampling and Methods of Analysis. 2nd Ed. Canadian Society of Soil Science, CRC Press. 1224 p. Fender, W.M. 1995. Native Earthworms of the Pacific Northwest: An Ecological Overview. In: Hendrix, P.F. (ed.) Earthworm Ecology and Biogeography in North America. CRC Press, Boca Raton, Florida.Fender, William. 2009. Personal communication with Sarah Foltz Jordan.

Fender, W.M. and D. McKey-Fender. 1990. Oligochaeta: Megascolecidae and Other Earthworms from Western North America. p. 357-378. In: Dindal, Daniel L. (ed.) Soil Biology Guide. Wiley and Sons, New York, New York.Fender, W. 2009. Personal communication with Sarah Foltz Jordan, the Xerces Society. William Fender, Independent Consultant, Portland, OR, 97205.

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Gervais, J. 2008. Details of “Rediscovery” of Oregon Giant Earthworm in 2008. Unpublished report. [Further details can be obtained by contacting: Dr. Jennifer Gervais, Oregon Wildlife Institute].

James, S. 2010. University of Kansas Biodiversity Institute. Personal communication with Sarah Foltz Jordan.

Johnson-Maynard, J. and C.M. Baugher. 2015. Driloleirus americanus Surveys in Washington State-Final Report. Report to the US Fish and Wildlife Service. 20 p.Rosenberg, D. 2009. Personal communication with Sarah Foltz-Jordan, the Xerces Society. Dan Rosenburg, Oregon State University and Oregon Wildlife Institute, Corvallis, OR 97331. March 27.

Smith, F. 1937. New North American species of earthworms of the family Megascolecidae. United States National Museum, Proceedings, Volume 84, pages 157-181. [Driloleirus macelfreshi, as Megascolides macelfreshi, is named on pages 166-168. This publication is in the University of Oregon science library under Q11.U55.]

[USFWS] United States Fish and Wildlife Service. 2011. Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To List the Giant Palouse Earthworm (Driloleirus americanus) as Threatened or Endangered. Federal Register 76(143):44547-44564.

Wells, S.M., R.M. Pyle, and N.M. Collins. 1983. The IUCN Invertebrate Red Data Book. IUCN, Gland, Switzerland. 632 pp.[WD4C] Working Dogs for Conservation. 2015. Projects. Bozeman, MT 59771. [website] Available at: http://www.workingdogsforconservation.org/ (Last accessed June 2018).

Xu, S., J.L. Johnson-Maynard, and T.S. Prather. 2013. Earthworm density and biomass in relation to plant diversity and soil properties in a Palouse prairie remnant. Applied Soil Ecology 72:119–127.

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