SPECIES FACT SHEET

Scientific Name: Nanonemoura wahkeena Jewett, 1954

Common Name: Wahkeena Falls flightless stonefly

Phylum: Arthropoda

Class: Insecta

Order: Plecoptera

Family: Nemouridae

(Baumann and Fiala 2001; Stark et al. 2009; DeWalt et al. 2020)

Synonyms: Nemoura wahkeena (Jewett 1954); Zapada wahkeena (Illies 1966)

Type Locality: Wahkeena Creek, Columbia River Gorge, Multnomah County, Oregon (Jewett 1954).

Conservation Status:

Global Status: G2 – Imperiled (last reviewed 2 September 2009)  National Status (United States): N2 

State Status: S1 (Oregon)

(NatureServe 2020)

Federal Status (United States): Not Listed; Candidate Review for Listing as Endangered or Threatened Species (USFWS 1991; 2020)

IUCN Red List: Not assessed (IUCN 2020)

Taxonomic Note:

Jewett (1954) originally named this species Nemoura wahkeena, and tentatively assigned it to the subgenus Zapada. When Zapada was elevated to genus status, this species became known as Z. wahkeena (Illies 1966 as cited in Baumann and Fiala 2001); however, the generic assignment of this species and several other nemourids was considered questionable since no new specimen material was available for study at the time (Baumann 1975). Subsequently, this species was included in the Zapada genus in publications by several authors (Stark et al. 1986; Stewart and Stark 1988; Stark et al. 1998) until more recent work by Baumann and Fiala (2001) resulted in the placement of this species in a new, monospecific genus, Nanonemoura. Z. wahkeena is still recognized as the valid name for this species by ITIS (2020); however, according to Stark et al. (2009) and DeWalt et al. (2020), Nanonemoura wahkeena is the currently accepted name for this species.

Technical Description:

Adult: This species belongs to a newly described, monospecific genus (Nanonemoura) in the family Nemouridae. The Nemouridae belongs to the Euholognatha infraorder within Arctoperlaria suborder. Euholognathan families, including Nemouridae, share morphological characters that unite the group: (1) segmental nerves that cross under longitudinal abdominal muscles (nerves lie on top of muscles in other Plecoptera); (2) an unpaired corpus allatum fused to the aorta; and (3) a soft chorion of the egg (Zwick 2000). Species in the Nemouridae family, known as spring stoneflies, are distinguished from other plecopteran families by the following set of characters: front wings generally held flat at rest with an apical cross-vein, labium with glossae and paraglossae about the same size, basal tarsal segment short (much shorter than third segment), second segment of tarsi very short (much shorter than both the basal and third segments), and cerci short and one-segmented (Triplehorn and Johnson 2005; Stewart and Stark 2008).

The general appearance of this species is like a small grasshopper nymph (Baumann and Fiala 2001). The body is dark brown dorsally, and lighter in color ventrally. The legs are yellow, darker at joints, and quite long, especially the hind legs, which are more than twice the length of the abdomen. The wings are very small and vestigial (micropterous), and seldom extend beyond the thorax. The wing venation is reduced to major veins, with few cross veins. The eyes are large and prominent, and the antennae are long, with around 35 segments. The maxillary palpi are long. The thorax is stout with oversized legs, and wings on the dorsolateral margins. The abdomen is as long as the head and thorax combined. Abdominal cerci are one-segmented (Baumann and Fiala 2001). Adults are easily distinguished from all other taxa in the Nemourinae (including the Nearctic genera: Lednia, Vioska, and Zapada) subfamily by the long maxillary palpi, micropterous wings, and very long legs, especially the hindlegs (Baumann and Fiala 2001). Differences in genitalia are also apparent between Nanonemoura and the closely related Zapada, Lednia, and Visoka genera (Baumann and Fiala 2001).

Descriptions of the adult male and female genitalia of Nanonemoura wahkeena from Baumann and Fiala (2001) are described as follows:

MALE GENITALIA. The epiproct is lightly sclerotized apically and laterally at median expanded areas, and covered with numerous rows of small, wart-like processes. The large dorsal sclerite of the epiproct extends over the entire dorsal surface. The ventral sclerite is heavily sclerotized, subequal in area to dorsal sclerite, and bears around 30 stout, ventrally directed spines that are randomly spaced over most of ventral surface. The paraprocts have a heavily sclerotized inner lobe that terminates in a sharply bifurcate apex; the outer lobe is partially membranous, with a sclerotized outer margin, bearing around 25 short stout spines. The hypoproct is broadest at base, with the anterior 1/3 tapering to truncate apex, bearing a thin, sharp, pointed projection medially. The vesicle is present, thin and elongate. The cerci are sclerotized dorsolaterally and drawn out into a narrow apex that ends in a hooked tip. The diagnostic features of the male genitalia are as follows: (1) the epiproct consists of dorsal and ventral sclerites that are large and flat and approximate each other in size, (2) the dorsal sclerite has lightly sclerotized, slightly swollen areas medio-laterally, covered by rows of small, wart-like processes, (3) the ventral sclerite has around 30 stout ventrally directed spines scattered over the entire ventral surface, and (4) the paraprocts have two well-developed lobes, the inner lobe darkly sclerotized, narrow, and with a bifurcate apex. See Baumann and Fiala (2001) for illustrations of the genitalia of this species.

FEMAL GENITALIA. The seventh sternum is enlarged into a pregenital plate, broadly rounded and extending over most of the eighth sternum. The eighth sternum is more darkly sclerotized, forming a small subgenital plate with a narrow, dark sclerotized band over the vaginal opening. The cerci are membranous but large and long, almost like tiny ears. The two diagnostic features of the female genitalia are the well-developed pregenital plate covering most of the next segment, and the small sclerotized bar over the vaginal opening. See Baumann and Fiala (2001) for illustrations of the genitalia of this species.

Nymph: Nymphs of N. wahkeena are typical for the family (Baumann 2020, pers. comm.). Other nemourids are small, robust, and hairy, less than 12 mm (0.5 in.) in body length (Stewart and Stark 2008). They are distinguished from other stonefly families by the following characters: paraglossae and glossae about equal in size; gills not conical; no ventral gill tufts; hind legs reaching about the tip of the abdomen; midline of the metathoracic wing pads strongly divergent from the body axis; and cervical gills present (Stewart and Stark 2008).

The nymph of this species is uniformly brown in color, with a darker pattern on head and thorax (Baumann and Fiala 2001). The head is covered with numerous tiny hairs, and the eyes are prominent. The thorax bears many long, darkly sclerotized spines. The pronotum is completely encircled, the meso- and metanotum bearing a pair of long, hair-like spines lateral to midline. The legs are short and stout. The femur bears 8–10 long spines scattered randomly on lateral margins, and the tibia bears two rows of short, stout spines, one on each lateral margin, and a sparse fringe of long, thin hairs on the ventral margin. The abdomen is without setae or spines, except for two rows of long, thin spines, one on each side of midline, running the entire length of abdomen. The cerci are well developed, and with around 20 segments. Intercalary spines are present. The anterior 2/3 of cercal segments are encircled with whorls of long spines. Two cervical gills are present on each side of the midline. The gills are thin and divided, with three lobes each. The lobes arise from midlength to apex, not from a common stalk. The nymph is distinct in having two pairs of cervical gills, each with three branches arising linearly and not from a common stalk. Additionally, the mostly random setation on the femora is diagnostic. Detailed illustrations of diagnostic features of the nymph of this species are provided in Baumann and Fiala (2011).

Egg: Eggs for this species have not been described. Other euholognathan taxa have round to slightly ovoid eggs with a soft, delicate chorion, without an anchor plate (Jewett 1959; Brittain 1973; Zwick 2000). Many in the infraorder have membranous eggs contained in a gelatinous matrix (reviewed in DeWalt 2015).

Life History:

Limited life history information exists for this species. Nanonemoura wahkeena belongs to the Nemouridae family, which includes one of the most productive and abundant stonefly faunas of predominately small, cold-water habitats in North America (reviewed in Hynes 1976; Baumann 1979; reviewed in Stewart and Anderson 2009). This species is included in the suborder Arctoperlaria, which includes the infraorders Euholognatha and Systellognatha (Zwick 2000; DeWalt et al. 2020). The differences between the two infraorders are represented in the details of their biology and morphology (Jewett 1959; Zwick 2000). N. wahkeena belongs to the former, which have nymphs that are primarily detritivores and adults that feed; the latter are generally carnivorous as nymphs and non-feeding as adults (Stewart and Stark 2002). As a monospecific genus, Nanonemoura is a narrow endemic, occurring only in seep and headwater spring habitat from a single watershed in the Columbia River Gorge (Jewett 1954; Baumann and Fiala 2001; Baumann 2011; 2020, pers. comm.; Fallon et al. 2016; GBIF 2020; ORBIC 2020). The majority of nemourid stoneflies are univoltine, though some are semivoltine or bivoltine (reviewed in Stewart and Stark 2008; Tierno de Figueroa et al. 2009; reviewed in DeWalt et al. 2015). The life cycle of N. wahkeena has not been documented, but other nemourids show flexibility in their development, with variability in voltinism and diapause (of egg or nymphal stages), which may be dependent on temperature (Lillehammer et al. 1989).

Adult: Very little is known about the life history of this species, including adult mating, oviposition, and dispersal behavior. Adult Plecoptera are generally short-lived, some living for several days to weeks (Brittain 1990; reviewed in Stewart and Stark 2008). Species that feed as adults (which, presumably includes N. wahkeena) are generally longer lived than those that do not feed (reviewed in Hynes 1976). Adults generally take refuge among riparian vegetation, rocks, or other substrate, and flightless taxa may crawl around riparian areas in the vicinity of the emergence site in search of food (reviewed in Hynes 1976; reviewed in Stewart and Stark 2008). Most female adult stoneflies (typically those with herbivorous nymphs) eat to acquire nutrients for their eggs (reviewed in Hynes 1976; Lillehammer et al. 1989). While the diet is varied, feeding appears to be important for both male and female nemourids (Tierno de Figueroa and Sánchez-Ortega 2000). The adult feeding behavior of this species is unknown, but other taxa in the family are known to feed on epiphytic algae, fungal hyphae and spores, cyanolichens, cyanophyceae, or the young leaves, buds, and pollen of riparian vegetation (Tierno de Figueroa and Sánchez-Ortega 2000; reviewed in Stewart and Stark 2008).

Many Plecoptera have evolved brachypterous (shortened or reduced) wings and likely travel only short distances from the emergence site. N. wahkeena possess micropterous (small, vestigial) wings, indicating that the adults are flightless. Dispersal ability is therefore likely poor for stoneflies (Brittain 1990), and is reflected in the high proportion of endemism in this group (Fochetti and Tierno de Figueroa 2008). For narrow endemics like N. wahkeena dispersal is presumably very minimal in the adult stage. As a flightless stonefly, this species uses long legs to hop around its terrestrial environment, similar to a grasshopper (Baumann and Fiala 2001; Fallon et al. 2016). Mating likely takes place near the natal habitat, and may occur on or near the ground, or with the shelter of rocks or vegetation (Brittain 1990). Females release egg masses over the water surface from various heights or land on the water surface to deposit them directly in the water (reviewed in Stewart and Stark 2008; reviewed in DeWalt et al. 2015). Euholognathan females, which include this species, likely lay eggs within a sticky gelatinous layer (others have specialized anchoring devises for attachment) allowing them to affix easily to the substrate; while others may simply disperse eggs into the benthos (reviewed in Stewart and Stark 2008; reviewed in DeWalt et al. 2015). All Plecoptera have semelparous reproduction, producing one generation in a life cycle (reviewed in DeWalt et al. 2015).

As cold-water taxa, stoneflies in the family are typically early to emerge in the spring in Oregon. The emergence season of this species is not well-documented, although known records for adults are from late March to late May.

Nymph: The nymphal behavior and diet of this species are unknown. While specific feeding behaviors of N. wahkeena nymphs have not been observed, other members of the Nemouridae family are primary consumers and classified as detritivores (reviewed in DeWalt 2009). Similar to other detritivorous stonefly taxa, N. wahkeena nymphs are likely shredders and scrapers or facultative collector—gatherers (reviewed in Stewart and Stark 2008). Nemourids are known to use a variety of fine and coarse dead and decaying plant materials, including leaves, microalgae, and associated biofilms (reviewed in Stewart and Stark 2008; reviewed in DeWalt 2009). Related nemourid taxa (e.g., Nemoura and Zapada genera) are generally sprawlers-clingers, and cryptic, likely concealed among the decaying leaf litter and other detritus that they feed on (reviewed in Merritt et al. 2008; reviewed in DeWalt 2009). The life cycle (usually annual or univoltine) of some species is intricately tied to the high abundance of resources provided from autumnal leaf fall (Stewart and Stark 2002).

The duration of the nymphal stage is unknown. Nymphs molt several times as they grow, and the number of nymphal instars may vary largely between and within Plecoptera taxa and may also be dependent on gender and temperature; however, 12-16 nymphal instars have been observed in several Nemoura taxa (reviewed in Hynes 1976). Nymphs crawl from the water to emerge as adults. Only one N. wahkeena nymph has been collected in late February (Baumann and Fiala 2001).

Egg: The egg stage of this species has not been described. Many plecopterans lay a large number of eggs, and fecundity ranges from 100-2,000 eggs per female (Brittain 1990). Some species may undergo diapause in the egg stage, but it is not as common as direct embryonic development; this is presumably reflected in lower thermal demand for egg development in many stenothermal plecopterans (Brittain 1990). In Plecoptera with direct embryonic development, the egg stage may be complete in about 3-4 weeks (reviewed in Stewart and Stark 2008).

Range, Distribution, and Abundance:

Range: Nanonemoura wahkeena occurs along the Columbia River Gorge Scenic Area (CRGNSA) in Oregon.

Distribution: This species is a narrow Columbia Gorge endemic, only known from Wahkeena Creek in the Wahkeena Falls area of the CRGNSA, Multnomah County, Oregon.

BLM/Forest Service land:

Documented: This species is documented from the CRGNSA in Oregon.

Suspected: This species is not suspected on additional BLM/Forest Service lands in Oregon.

Abundance: Abundance estimates at known population sites have not been conducted, although population sizes are presumably small. Recorded collections range from one to twenty adults (Baumann 2011, pers. comm.).

Habitat Associations:

As a group, the Nemouridae family is a characteristic component of the aquatic macroinvertebrate fauna of temperate forested regions (Fochetti and Tierno de Figueroa 2008). Nemourid nymphs require well-oxygenated waters and are common in a variety of cool, lotic freshwater habitats (Hynes 1976). Nanonemoura wahkeena is associated with a very narrow community in the Wahkeena Creek watershed in the Columbia River Gorge National Scenic Area (CRGNSA). It is endemic to and exclusively found at two localities associated with Wahkeena Creek (Jewett 1954; Baumann and Fiala 2001; Baumann 2011, pers. comm.; Fallon et al. 2016; GBIF 2020; ORBIC 2020). Known habitat for N. wahkeena adults includes two discrete sites adjacent to Wahkeena Creek which host this species, (1) a large seepage area along the trail to the upper Wahkeena Creek spring (Baumann and Fiala 2001; Baumann 2020, pers. comm.); and (2) near the large spring head itself (see Attachment 4 for Wahkeena Creek springhead habitat photos) (Wisseman 2015; Fallon et al. 2016). A nymph has been collected in a large seepage complex associated with Wahkeena Creek (Baumann and Fiala 2001).

The specific aquatic microhabitat of nymphs of this species is not known. They are likely found in detritus and mosses at the edges of seeps and springs, similar to others in the family (Wisseman 2015; Glime 2017). Related nemourid taxa are sprawlers—clingers, and cryptic, likely concealed among the decaying leaf litter and other detritus that they feed on (reviewed in Merritt et al. 2008; reviewed in DeWalt 2009). Sites range in elevation from 380 to 470 m (1,250 to 1,540 ft.). This species co-occurs with other sensitive aquatic macroinvertebrates endemic to Wahkeena Creek watershed, including Neothremma andersoni (Columbia Gorge caddisfly; Forest Service Region 6 Sensitive Species) (Fallon et al. 2016).

Threats:

While direct threats to this species are not documented, Plecoptera in general are among the most ecologically sensitive groups of aquatic fauna worldwide (Baumann 1979; Master et al. 2000; DeWalt 2009). Most plecopteran species have highly specific preferences with regard to water temperature, velocity, dissolved-oxygen levels, and substrate characteristics, and are therefore sensitive to a wide array of habitat alterations (reviewed in DeWalt et al. 2015). Since this species likely requires cold, spring-fed and seep habitat for nymphs and intact riparian systems for adults, any activities that degrade water quality or terrestrial habitat would likely have negative impacts. Its very limited range places this species at greater risk of extinction from various imminent and potential threats to its habitat.

The primary imminent threats to N. wahkeena are habitat alteration and degradation, recreation use, and climate change (CRGC 2016; Fallon et al. 2016). Recreation may be the most visible and imminent threat to this species’ habitat and other aquatic and riparian ecosystems in the CRGNSA (Burns et al. 2013; Fallon et al. 2016). This species occurs in popular, high-use recreation areas with nearby trails and trailheads, and the impacts from recreation have led to perceivable resource degradation (Burns et al. 2013). Its restricted range to only two small sites in the Wahkeena Creek basin makes N. wahkeena particularly vulnerable to habitat alterations (Wisseman 2015; Fallon et al. 2016).

Some forested lands of the CRGNSA are privately owned and as such do not have similar protections as federal or state lands (CRGC 2016). The loss of riparian habitats and wetlands as a result of little to no existing protections in some cases, poses a significant threat to aquatic habitats in this scenic area (CRGC 2016). Since riparian areas provide habitat for adults and help maintain appropriate aquatic habitat for nymphs, habitat degradation will cause undue harm to this species. Loss of streamside vegetation may lead to erosional concerns along streambanks, alter stream temperature, and impair stream ecological processes. Increased erosion can result in high sediment loads in seep habitat and interrupt flows, creating an added stressor for seep and spring-associated taxa.

Continued global climate change further threatens the long-term survival of this species and can exacerbate other threats. Climate change is an imminent threat to stoneflies in montane habitats (Tierno de Figueroa et al. 2010), and for aquatic and riparian ecosystems of the Pacific Northwest (reviewed in Tillmann and Siemann 2011; reviewed in Wozniak 2019). Projected effects of climate change in this region include increased frequency and severity of seasonal droughts and flooding, reduced snowpack to feed river flow, earlier snowmelt reducing summer flows, increased siltation, and increased air and water temperatures (Jung and Chang 2012; Jiménez Cisneros et al. 2014; Mote et al. 2018; USGCRP 2018), all of which could impact this species and its habitat unfavorably. In the CRGNSA, where this species occurs, changes in climate are projected to significantly alter the timing, and the quantity and quality of water available to aquatic ecosystems (reviewed in Wozniak 2019). These changes can further threaten species like N. wahkeena that are already at risk due to their narrow range and microclimate requirements. As macroinvertebrates respond to climate change, ecological mismatches may occur, including: (1) phenological changes (e.g., earlier emergence as a result of increasing temperatures); (2) community composition changes (e.g., reductions in sensitive taxa as a result of temperature and/or flow alterations); and (3) functional role fluctuations in aquatic habitats (e.g., changes in allochthonous inputs and/or autochthonous sources of organic material—which drive aquatic food webs—will exclude communities that rely on these inputs); among others (Sytsma 2010; reviewed in Tillmann and Siemann 2011).

Additionally, over-collecting may threaten this species, since published sites in the Columbia River Gorge are easy for collectors to access, and populations are already small and presumably vulnerable (Wisseman 2011, pers. comm.). This may be an additional concern for the conservation of rare Oregon Plecoptera since some sites have been extensively surveyed for aquatic invertebrates (Wisseman 1990; 1991).

Conservation Considerations:

Because this species belongs to a monospecific genus and is endemic to a single creek system, it is considered a high priority for conservation.

Research: Research on basic life history aspects is lacking for this species as currently very little is known of the phenology and specific microhabitat needs of the immature life stage. Collections and determinations of nymphs would provide information on habitat associations and requirements for this life stage. Basic knowledge of the longevity and activity of adults, nymphs, microhabitat, and feeding habitats, will provide a baseline for protection of the species and its terrestrial and aquatic habitat. Nymphal and adult material from museum collections could be provided for CO1 DNA barcoding to further validate species determinations. Although there continues to be a lack of knowledge of some aspects of this species’ life history, its known habitat is very sensitive to disturbance; if surveys are warranted, researchers should use extreme care to avoid disruption to the highly sensitive habitat where the species occurs.

Inventory: Despite repeated attempts to find this species in other localities in the Columbia River Gorge, especially along the trail to, and at, nearby Multnomah Falls, it is still known only from the Wahkeena Creek site (Baumann and Fiala 2001; Baumann 2011; 2020, pers. comm.; Wisseman 2015; Fallon et al. 2016). At the Wahkeena Creek site, this species has been reliably encountered in the appropriate habitat since 1982, and was last documented in 2015 (Fallon et al. 2016). Since the habitat of this species is very fragile and sensitive to damage from collectors (Wisseman 2011, pers. comm.), any surveys at this site should be carried out with extreme care. The Eagle Creek fire in 2017 impacted large portions of the CRGNSA, including the Wahkeena trail and habitat around Wahkeena Creek and the springhead. While ground-level vegetation was not burned around the seep and main spring (where most individuals have been documented), there were losses in canopy cover (Wisseman 2020, pers. comm.) (see Attachment 4 for post-fire photos); therefore, it is recommended to revisit the site to ensure the population remains extant and assess any potential long-term effects on this species’ habitat.

Stonefly habitat in the area has been thoroughly surveyed for this species over a period of several decades, so additional population sites may be unlikely (Baumann 2011, pers. comm.). However, under-surveyed sites could still exist (Fallon et al. 2016). Two potential sites (which likely see few visitors and/or have no trail access) in the Columbia River Gorge have similar habitat characteristics (cold, high gradient, spring-fed creeks) to Wahkeena Creek. These include possible headwater habitat in the Multnomah Creek basin and another in the Mist Creek basin (see Fallon et al. [2016] for specific locations). These sites could be surveyed for this species and other rare and sensitive invertebrates that have similar habitat needs (e.g., Neothremma andersoni [Forest Service Region 6 Sensitive Species]) (Fallon et al. 2016; FS ISSSSP Database 2019).

Management: Known sites and their watersheds could be protected from heavy recreational use, trail development, road construction, and other practices that would adversely affect any aspect of this species’ life cycle. The Wahkeena Creek basin hosts multiple Columbia Gorge endemics and therefore, is an especially important site for protecting sensitive aquatic invertebrates (Fallon et al. 2016). Spring and seep habitats where N. wahkeena is found are particularly vulnerable to natural and human disturbances. Because this site is an important stronghold for this species and other sensitive invertebrates, it would benefit from protection and monitoring (Fallon et al. 2016).

Riparian habitat protection, including maintenance of water quality, substrate conditions, and canopy cover, would likely benefit and help maintain populations of this species. Protecting known upland adult habitat will not only benefit this species, but also co-occurring rare species. Maintaining intact riparian buffers would retain trees and shrubs along streambanks to help reduce erosion. Threats can be mitigated by creating suitable buffers from actively managed areas and any pesticide applications, limiting road construction activities and decommissioning unused roads, and implementing erosion and sedimentation prevention. Managing for stream health and stability is important for sensitive aquatic invertebrates and beneficial for ecosystem health as stable streams are less likely to become degraded.

Recreation may be the most visible and imminent threat that can be easily mitigated to protect this species’ habitat. Its restricted range to two small sites in the Wahkeena Creek basin makes it particularly vulnerable to habitat degradation, with most recent CRGNSA surveys of endemic invertebrates turning up just a few individuals at Wahkeena Spring (Fallon et al. 2016). Fallon et al. (2016) indicate that land managers could consider closing off trail access to the spring to protect this site from high recreation use. Another trail that already exists directly downstream of the springhead could serve as the primary trail (Fallon et al. 2016). R. Wisseman revisited the site in 2019 after the 2017 Eagle Creek fire and assessed burn impacts around the Wahkeena springhead. Following impacts from the fire, Wisseman (2020, pers. comm.) suggests it is an appropriate time to re-route the trail further from the springhead, especially away from the west side of the seep.

Version 3:

Prepared by: Michele Blackburn

Xerces Society for Invertebrate Conservation

Date: May 2020

Edited by: Candace Fallon

Xerces Society for Invertebrate Conservation

Date: May 2020

Version 2:

Prepared by: Sarah Foltz Jordan

Xerces Society for Invertebrate Conservation

Date: December 2011

Edited by: Sarina Jepsen

Xerces Society for Invertebrate Conservation

Date: December 2011

Version 1:

Prepared by: Eric Scheuering

Date: January 2006

Edited by: Rob Huff

Conservation Planning Coordinator, FS/BLM-Portland

Date: June 2007

Recommended citation:

Blackburn, M., S. Foltz Jordan, and E. Scheuering. 2020. Interagency Special Status/Sensitive Species Program (ISSSSP) Species Fact Sheet: Nanonemoura wahkeena. USDA Forest Service Region 6 and USDI Bureau of Land Management Oregon State Office. 26 pp. Available at: https://www.fs.fed.us/r6/sfpnw/issssp/species-index/fauna-invertebrates.shtml       

ATTACHMENTS:

(1) References

(2) List of pertinent or knowledgeable contacts

(3) Map of known records

(4) Illustrations of this species and habitat photos

(5) Plecoptera Survey Protocol, including specifics for this species

ATTACHMENT 1: References

Baumann, R.W. 1975. Revision of the stonefly family Nemouridae (Plecoptera): a study of the world fauna at the generic level. Smithsonian Contributions to Zoology 211:1–74. Available at: https://repository.si.edu/bitstream/handle/10088/5284/SCtZ-0211-Lo_res.pdf?sequence=2&isAllowed=y [Accessed May 2020].

Baumann, R.W. 1979. Nearctic stonefly genera as indicators of ecological parameters (Plecoptera: Insecta). Great Basin Naturalist: 39(3):241-244. Available at: https://scholarsarchive.byu.edu/gbn/vol39/iss3/5 [Accessed May 2020].

Baumann, R.W. 2011. Personal communication with Sarah Foltz Jordan, the Xerces Society for Invertebrate Conservation. Richard W. Baumann, Emeritus curator and collection manager of entomology, Brigham Young University, Provo, UT.

Baumann, R.W. 2020. Personal communication with Michele Blackburn, the Xerces Society for Invertebrate Conservation. Richard W. Baumann, Emeritus curator and collection manager of entomology, Brigham Young University, Provo, UT.

Baumann, R.W. and G.R. Fiala. 2001. Nanonemoura, a new stonefly genus from the Columbia River Gorge, Oregon (Plecoptera: Nemouridae). Western North American Naturalist 61(4): 403-408.

Brittain, J.E. 1973. The biology and life cycle of Nemoura avicularis Morton (Plecoptera). Freshwater Biology 3:199-210.

Brittain, J.E. 1990. Life history strategies in Ephemeroptera and Plecoptera. In: Mayflies and stoneflies: Life histories and biology. I.C. Campbell (ed.). Kluwer Academic Publishers, Dordrecht, the Netherlands. pp. 1-12.

Burns, R., T. Chuprinko, and S. Shrestha. 2013. Columbia River Gorge meta-analysis: A spatial and temporal examination of outdoor recreation. West Virginia University. 132 pp.

[CRGC] 2016. Columbia River Gorge Commission. Management plan for the Columbia River Gorge National Scenic Area. Prepared by the Columbia River Gorge Commission, White Salmon, Washington and the USDA Forest Service, National Scenic Area, Hood River, Oregon. 467 pp.

DeWalt, R.E. 2009. Plecoptera (Stoneflies). In: Encyclopedia of inland waters. Eds. G.E. Likens. Academic Press. pp. 415-422.

DeWalt, R.E. and B.C. Kondratieff, and J.B. Sandberg. 2015. Order Plecoptera. In: Thorp and Covich’s Freshwater Invertebrates – Volume 1: Ecology and General Biology. Eds. J.H. Thorp and D.C. Rogers. Elsevier, San Diego, CA. pp. 933-949.

DeWalt, R.E., M.D. Maehr, H. Hopkins, U. Neu-Becker, and G. Stueber. 2020. Plecoptera Species File Online. Version 5.0/5.0. http://Plecoptera.SpeciesFile.org. [Accessed May 2020].

Fallon, C., E. Blevins, and R. Wisseman. 2016. Surveys to determine the status and distribution of three Columbia River Gorge endemic caddisfly and stonefly species: Farula constricta, Neothremma andersoni, and Nanonemoura wahkeena. Final report from the Xerces Society and Aquatic Biology Associates, Inc. to the Interagency Special Status/Sensitive Species Program (ISSSSP) and the Columbia River Gorge National Scenic Area (CRGNSA). Assistance Agreement L13AC00102, Modification 3. March 2016. 101 pp.

Fochetti, R. and J.M. Tierno de Figueroa. 2008. Global diversity of stoneflies (Plecoptera; Insecta) in freshwater. Hydrobiologia 595(1): 365-377.

FS ISSSSP Database. 2019. FINAL Region 6 Regional Forester Special Status Species List, March 13, 2019.

[GBIF] 2020. Global Biodiversity Information Facility. [online database]. Available at: www.gbif.org [Accessed May 2020].

Glime, J. M. 2017. Aquatic Insects: Hemimetabolous Insects – Plecoptera. Chapter 11-6. In: Glime, J. M. Bryophyte Ecology. Volume 2. Bryological Interaction. Ebook sponsored by Michigan Technological University and the International Association of Bryologists. Last updated 21 April 2017. Available at: http://digitalcommons.mtu.edu/bryophyte-ecology2/ [Accessed May 2020].

Hynes, H.B.N. 1976. The biology of Plecoptera. Annual Review of Entomology 21: 135-153.

Illies, J. 1966. Katalog der rezenten Plecoptera. Walter de Gruyter and Company, Das Tierreich 82. 631 pp.

[ITIS] 2020. Integrated Taxonomic Information System (ITIS) on-line database: Zapada wahkeena Jewett, 1954. Taxonomic Serial No.: 102604. Available at: http://www.itis.gov [Accessed May 2020].

[IUCN] 2020. International Union for Conservation of Nature and Natural Resources. The IUCN Red List of Threatened Species. Version 2020-1. Available at: https://www.iucnredlist.org [Accessed May 2020].

Jewett, S.G., JR. 1954. New stoneflies from California and Oregon. Pan-Pacific Entomologist 30:167–179.

Jewett, S.G., JR. 1959. The Stoneflies (Plecoptera) of the Pacific Northwest. Prepared by the U.S. Bureau of Commercial Fisheries, Portland, Oregon. Published by Oregon State University, Corvallis, Oregon. College Press. 102 pp.

Jiménez Cisneros, B.E., T. Oki, N.W. Arnell, G. Benito, J.G. Cogley, P. Döll, T. Jiang, and S.S. Mwakalila. 2014. Freshwater resources. In: Climate Change 2014: Impacts, Adaptation, and Vulnerability. Part A: Global and Sectoral Aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Field, C.B., V.R. Barros, D.J. Dokken, K.J. Mach, M.D. Mastrandrea, T.E. Bilir, M. Chatterjee, K.L. Ebi, Y.O. Estrada, R.C. Genova, B. Girma, E.S. Kissel, A.N. Levy, S. MacCracken, P.R. Mastrandrea, and L.L. White (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, p. 229-269.

Jung, I. W. and H. Chang. 2012. Climate change impacts on spatial patterns in drought risk in the Willamette River Basin, Oregon, USA. Theoretical and Applied Climatology 108(3-4):355-371.

Lillehammer, A., J.E. Brittain, S.J. Saltveit, and P.S. Nielsen. 1989. Egg development, nymphal growth and life cycle strategies in Plecoptera. Ecography 12(2):173-186.

Master, L.L., B.A. Stein, L.S. Kutner, G.A. Hammerson. 2000. Vanishing assets: Conservation status of US species. In: Precious Heritage: The status of biodiversity in the United States. Stein BA, Kutner LS, and Adams JS, editors. New York: Oxford University Press. pp 93-118.

Merritt, R.W., K.W. Cummins, and M.B. Berg. 2008. An Introduction to the aquatic insects of North America. Fourth Edition. Kendall/Hunt Publishing Co., Dubuque, Iowa. 989 pp.

Mote, P.W., S. Li, D.P. Lettenmaier, M. Xiao, and R. Engel. 2018. Dramatic declines in snowpack in the western US. Npj Climate and Atmospheric Science 1(1): 1-6.

NatureServe. 2020. Nanonemoura wahkeena Jewett, 1954. NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available at: https://explorer.natureserve.org/ [Accessed May 2020].

[ORBIC] 2020. Oregon Biodiversity and Information Center. GIS export provided to Candace Fallon, the Xerces Society, by Lindsey Wise, Biodiversity Data Manager, January 2020.

Stark, B.P., Baumann, R.W., DeWalt, R.E. 2009. Valid stonefly names for North America. Available at: https://web.archive.org/web/20130929005426/http://plsa.inhs.uiuc.edu/plecoptera/validnames.aspx [Accessed May 2020].

Stark, B.P., S.W. Szczytko, and R.W. Baumann. 1986. North American stoneflies (Plecoptera): systematics, distribution, and taxonomic references. Great Basin Naturalist 46:383–397. Available at: https://www.biodiversitylibrary.org/page/7797581#page/405/mode/1up [Accessed May 2020].

Stark, B.P., K.W. Stewart, S.W. Szczytko, and R.W. Baumann. 1998. Common names of stoneflies (Plecoptera) from the United States and Canada. Ohio Biological Survey Notes 1:1–18.

Stewart, K.W. and N. H. Anderson. 2009. The life history and larval generic character development of Malenka bifurcata (Claassen, 1923) (Plecoptera: Nemouridae) in an Oregon summer-dry stream. Aquatic Insects 31(1):391-399.

Stewart, K.W. and B.P. Stark. 2002. Nymphs of North American stonefly genera (Plecoptera). 2nd ed. Columbus, Ohio: The Caddis Press. Columbus, Ohio. 510 pp.

Stewart, K.W. and B.P. Stark. 2008. Chapter 14. Plecoptera. pp. 311-384. In An introduction to the aquatic insects of North America. 4th edition. Merritt, R.W., K.W. Cummins, and M.B. Berg (eds). Kendall/Hunt Publishing Co., Dubuque, Iowa.

Sytsma, M.D. 2010. Case Study 7: Oregon's Fish and Wildlife in a Changing Climate. In: The Oregon Climate Change Assessment Report. K.D. Dello and P.W. Mote (eds). Oregon Climate Change Research Institute, College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, OR. 96 pp.

Tierno de Figueroa, J.M., T. Bo, M.J. López-Rodríguez, and S. Fenoglio. 2009. Life cycle of three stonefly species (Plecoptera) from an Apenninic stream (Italy) with the description of the nymph of Nemoura hesperiae. Annales de la Société Entomologique de France 45(3): 339-343.

Tierno de Figueroa, J.M., M.J. López-Rodríguez, A. Lorenz, W. Graf, A. Schmidt-Kloiber, D. Hering. 2010. Vulnerable taxa of European Plecoptera (Insecta) in the context of climate change. Biodiversity and Conservation 19:1269–1277.

Tierno de Figueroa, J.M., and A. Sánchez-Ortega. 2000. Imaginal feeding of twelve Nemouroidean stonefly species (Insecta, Plecoptera). Annals of the Entomological Society of America 93(2):251-253.

Tillman, P. and D. Siemann. 2011. Climate change effects and adaptation approaches in freshwater aquatic and riparian ecosystems in the North Pacific landscape conservation cooperative region. National Wildlife Federation. 291 pp.

Triplehorn, C. and N. Johnson. 2005. Introduction to the Study of Insects. Thomson Brooks/Cole, Belmont, CA. 864 pp.

[USFWS] 1991. United States Fish and Wildlife Service. Endangered and Threatened Wildlife and Plants; Animal Candidate Review for Listing as Endangered or Threatened Species. Zapada (=Nemoura) wahkeena. November 21, 1991. Federal Register 56(225): 58804–58836.

[USFWS] 2020. United States Fish and Wildlife Service. Environmental Conservation Online System (ECOS). Online database. Available at: https://ecos.fws.gov/ecp0/reports/ad-hoc-species-report-input [Accessed May 2020].

[USGCRP] 2018. U.S. Global Change Research Program. Impacts, Risks, and Adaptation in the United States: Fourth National Climate Assessment, Volume II [Reidmiller, D.R., C.W. Avery, D.R. Easterling, K.E. Kunkel, K.L.M. Lewis, T.K. Maycock, and B.C. Stewart (eds.)]. Washington, DC, USA, 1515 pp.

Wisseman, R.W. 1990. A survey of the aquatic macroinvertebrate fauna of Wahkeena Creek, Columbia River Gorge, Oregon, submitted to the U.S. Fish and Wildlife Service, Portland Field Office. 82 pp.

Wisseman, R. 1991. Rhyacophila haddocki Denning 1968. Haddock’s rhyacophilan caddisfly. A technical report prepared for the Siuslaw National Forest, June 1991. 6 pp.

Wisseman, R. 2011. Personal communication with Sarah Foltz Jordan, the Xerces Society for Invertebrate Conservation. Robert Wisseman, Aquatic Biology Associates, Inc. Corvallis, OR.

Wisseman, R. 2015. Collecting sensitive aquatic invertebrate species in the Columbia River Gorge and adjacent Mount Hood area. Sensitive species workshop manual provided to participants of the Xerces/ISSSSP May 2015 training workshop. Unpublished document. 26 pp.

Wisseman, R. 2020. Personal communication with Candace Fallon and Michele Blackburn, the Xerces Society for Invertebrate Conservation. Robert Wisseman, Aquatic Biology Associates, Inc. Corvallis, OR. 1 June.

Wozniak, O. 2019. Summary of climate change effects in the Columbia River Gorge National Scenic Area. A report provided to the Columbia River Gorge Commission in support of Gorge 2020. Prepared by the Land Trust Alliance, Washington, D.C. 26 pp.

Zwick, P. 2000. Phylogenetic system and zoogeography of the Plecoptera. Annual Review of Entomology 45: 709–746.

Map references:

Baumann, R. 2011. Personal communication with Sarah Foltz Jordan, the Xerces Society for Invertebrate Conservation. Richard W. Baumann, Emeritus curator and collection manager of entomology, Brigham Young University, Provo, UT.

Baumann, R.W. and G.R. Fiala. 2001. Nanonemoura, a new stonefly genus from the Columbia River Gorge, Oregon (Plecoptera: Nemouridae). Western North American Naturalist 61(4): 403-408.

Fallon, C., E. Blevins, and R. Wisseman. 2016. Surveys to determine the status and distribution of three Columbia River Gorge endemic caddisfly and stonefly species: Farula constricta, Neothremma andersoni, and Nanonemoura wahkeena. Final report from the Xerces Society and Aquatic Biology Associates, Inc. to the Interagency Special Status/Sensitive Species Program (ISSSSP) and the Columbia River Gorge National Scenic Area (CRGNSA). Assistance Agreement L13AC00102, Modification 3. March 2016. 101 pp.

[GBIF] 2020. Global Biodiversity Information Facility. [online database]. Available at: www.gbif.org [Accessed May 2020].

Jewett, S.G. 1954. New stoneflies from California and Oregon. Pan-Pacific Entomologist 30(3):167-179.

[ORBIC] 2020. Oregon Biodiversity and Information Center. GIS export provided to Candace Fallon, the Xerces Society, by Lindsey Wise, Biodiversity Data Manager, January 2020.

ATTACHMENT 2: List of pertinent, knowledgeable contacts

Richard W. Baumann, Emeritus curator and collection manager of entomology, Brigham Young University, Provo, UT.

Robert Wisseman, Aquatic Biology Associates, Inc. Corvallis, OR.

ATTACHMENT 3: Map of known records

Records of Nanonemoura wahkeena, relative to Forest Service and BLM lands. The only known sites for this species are on Columbia River Gorge National Scenic Area land.

ATTACHMENT 4: Illustrations of this species

Nanonemoura wahkeena male adult, habitus. Illustration by Jean Stranger, extracted from Baumann and Fiala (2001), courtesy of Western North American Naturalist. Used with permission.

Nanonemoura wahkeena nymph, habitus (left) and ventral side showing two pairs of cervical gills, each with three branches (right). Illustrations by Jean Stranger, extracted from Baumann and Fiala (2001), courtesy of Western North American Naturalist. Used with permission.

Wahkeena Creek springhead (left) and just downstream of the springhead (right). Photos by Robert Wisseman/Aquatic Biology Associates.

Wahkeena Creek spring (upper left), Wahkeena Creek mainstem (upper right), and the trail between Wahkeena Spring and Mist Creek (bottom). Photos taken after the 2017 Eagle Creek fire in August 2019. Photos by Bob Wisseman/ Aquatic Biology Associates.

ATTACHMENT 5: Trichoptera Survey Protocol, including specifics for this species

Survey Protocol

By Sarah Foltz Jordan, the Xerces Society for Invertebrate Conservation

Taxonomic group:

Plecoptera

Where: Plecopterans utilize a diversity of freshwater aquatic habitats, including headwater springs, streams, rivers, seepage areas. They are mainly associated with lotic (moving water) habitats, although a number of species are known from large, oligotrophic lakes (Stewart and Stark 2008). Most species have highly specific preferences with regard to water temperature, velocity, dissolved-oxygen levels, and substrate characteristics. Nymphs are often highly specialized in their dietary preferences, and in the manner and location in which food is obtained. Most plecopterans are either shredder-detritivores or engulfer-predators, and feeding habits are usually consistent within a particular family (Voshell 2002). For species-specific diet and habitat information, see the section at the end of this protocol.

When: Adults are surveyed within the window of the species’ documented flight period. Nymphs are most conveniently surveyed at the same time as adults.

Adult: Adult plecopterans are predominantly encountered near water, close to their emergence or oviposition sites. Adults are frequently collected from riparian vegetation with an aerial sweep net; they can also be hand-picked from tree bark, the undersides of bridges and culverts, and from the sides and upper-surfaces of partly-submerged logs or under loose rocks. Since some species are attracted to light, adults can often be collected in large numbers in soapy-water pan traps placed under a light (e.g. a vehicle headlight) and left overnight. Specimens can also be collected at night directly from lights or an illuminated sheet using an aspirator or finger dipped in alcohol. An aspirator is especially useful for capturing small species. Emergence traps placed over habitat where the nymphs are known or suspected to occur are another good method for obtaining adults.

Adults should be killed and preserved in 95% grain alcohol, or killed in cyanide and transferred to alcohol. Cyanide-killed adults may also be pinned, particularly to preserve color patterns, but pinned adults often shrink, resulting in damage to the genitalia, gill remnants, and other critical aspects of the specimen (Triplehorn and Johnson 2005).

Since plecopteran identification often involves close investigation of adult genitalia, photographs and sight records will not provide sufficient evidence of species occurrences. However, such observations may be valuable in directing further study to an area.

Immature stages: The immature stages of stoneflies are found underwater, creeping slowly along the substrate or remaining stationary in a place with ample dissolved oxygen and current velocity (Voshell 2002). Nymphs often have a strong preference for coarse substrates, such as boulders, cobble, pebbles, pieces of water-soaked wood, and accumulations of coarse detritus (Voshell 2002).

When surveying for nymphs, care must be used to avoid disrupting stream banks, shorelines, vegetation, and habitat. Depending on the habitat, a variety of nets can be useful. D-frame nets with mesh size fine enough to retain small nymphs (0.5 mm, 0.02 in.) are the most versatile, as they can be used in both lotic and lentic habitats. In stream systems, the standard kick-net technique can be applied. The net is held vertically with the opening facing upstream and the flat side pressed tightly against the bottom substrate, so that water flows neither under nor over the net. Large rocks and wood immediately upstream of the net are gently scrubbed by hand or with a soft brush and the bottom substrate is disturbed with the hands, feet, or a stick while the current carries the uncovered and dislodged insects and material into the net. The stream bottom is disturbed to a depth of 4 – 6 cm (1.2 – 2 in.) for about three minutes, following which the net is removed from the water for specimen retrieval. When lifting the net, the bottom of the frame is swept forward in a scooping motion to prevent insects from escaping. Net contents are then flipped or rinsed into shallow white trays to search for nymphs more easily, as they are often quite cryptic and can be difficult to see if they are not moving. In addition to nets and shallow trays, the following equipment is also useful: fine-mesh strainers/sieves for washing mud and silt from samples, squirt bottles for rinsing the net, five-gallon buckets for holding rinsing water, and white ice-cube trays, forceps, and a hand lens for sorting insects.

Immature stages should be preserved on-site in 95% grain alcohol, unless collection for rearing is an objective. Since many plecopteran species have not been described in their nymphal stage, rearing can be critical in both (1) enabling species identification and (2) providing novel associations of nymphs with adults. Generally, final instar nymphs are more likely to survive to adulthood in rearing chambers than early nymphal stages. Detailed techniques for rearing stream-dwelling organisms in the laboratory, including transportation, aeration, current production, temperature control, food, and toxic substances, are provided by Craig (1966), and available online at http://www.nzetc.org/tm/scholarly/tei-Bio14Tuat02-t1-body-d1.html (last accessed 21 May 2020).

Although quantitative collecting of plecopterans is difficult, population-size data is important in evaluating a species’ stability at a given locality and in assessing its conservation needs. Relative abundances of immature plecopterans can be estimated by using a uniform collecting effort over a given sample period at comparable habitats. The area or volume of substrate samples can also be standardized, although the aggregated spatial distributions of many species can complicate this approach.

While researchers are visiting sites and collecting specimens, detailed habitat data should also be acquired, including substrate type(s), water temperature, water source, water velocity, water depth, stream width, canopy cover, streamside vegetation density, and degree of human impact. Algal or cyanobacterial blooms and other signs of eutrophication should be watched for and noted.

Species-specific Survey Details:

Nanonemoura wahkeena

Where: This rare species is known only from Wahkeena Creek in the Columbia River Gorge, Multnomah County, Oregon. It occurs in small to large seeps and springs along the creek, as well as the springhead itself. Despite repeated attempts to find this species in other localities in the Columbia River Gorge, particularly along the trail to Multnomah Falls, and at Multnomah Falls, it is still known only from the Wahkeena Creek site (Baumann and Fiala 2001; Baumann 2011; 2020, pers. comm.; Fallon et al. 2016). At the Wahkeena Creek site, the species has been reliably encountered in the appropriate habitat since 1982, and was most recently documented in 2015 (Baumann 2011, pers. comm.; Fallon et al. 2016). Since the habitat of this species is very fragile and sensitive to damage from collectors (Wisseman 2011, pers. comm.), any surveys at this site should be carried out with extreme care. The Eagle Creek fire in 2017 impacted large portions of the CRGNSA, including the Wahkeena trail and habitat around Wahkeena Creek and the springhead. While ground-level vegetation was not burned around the seep and main spring (where most individuals have been documented), there were losses in canopy cover (Wisseman 2020, pers. comm.); therefore, it is recommended to revisit the site to ensure the population remains extant and assess any long-term effects on this species’ habitat.

Since stonefly habitat in the area has been thoroughly surveyed for this species over a period of several decades, additional population sites may be unlikely (Baumann 2011, pers. comm.). However, under-surveyed sites could still exist. Two potential sites (which likely see few visitors and/or have no trail access) in the Columbia River Gorge have similar habitat characteristics to Wahkeena Creek. These include possible headwater spring habitat in the Multnomah Creek basin and another in the Mist Creek basin (see Fallon et al. [2016] for specific locations). These sites could be surveyed for N. wahkeena and other rare and sensitive invertebrates that have similar habitat needs (e.g., Neothremma andersoni [Forest Service Region 6 Sensitive Species]) (Fallon et al. 2016; FS ISSSSP Database 2019).

When: Springtime surveys have proven most productive for this species (Baumann and Fiala 2001). A nymph has been collected in late February, and adult collection records range from late March through late May.

How: Since both the nymph and adult stages of this species are described, rearing of immature stages is not necessary for identification.

Adult: The adult is approximately 5 mm (0.2 in.) in length, dark brown dorsally, and light brown ventrally (Wisseman 2015). They are flightless, and hop around like small, grasshopper nymphs with very long yellow legs (Baumann and Fiala 2001; Wisseman 2015). Adults are easily distinguished from all other taxa in the Nemourinae subfamily by the long legs (especially the hind legs, which are more than twice as long as the abdomen), long maxillary palpi, and very small, vestigial wings (Baumann and Fiala 2001). Despite their flightless behavior, they can be very active and difficult to capture (Wisseman 2015). According to Baumann (2011, pers. comm.), adults of this species are especially difficult to collect, and it usually takes someone to actually show you (first-hand) how to find it. Adults have been collected on riparian vegetation and on the ground near seeps. They are likely to be found near and up to 3 ft. (0.9 m) from pooled and flowing water, on and around the lower 1 ft. (0.3 m) of riparian vegetation (Sandberg 2015, pers. comm.). Because they are flightless, adults may be easily spotted by placing white paper towels or white beat sheets on the ground at the base of vegetation near suitable habitat (Sandberg 2015, pers. comm.). Surveyors can wait patiently (sometimes up to 30 minutes or more) for specimens to hop onto the paper towels and/or carefully tap overhanging vegetation to dislodge any adults resting on plants (Sandberg 2015, pers. comm.; Wisseman 2015). It is important to tap vegetation very gently; if vegetation is struck too hard or vigorously, it is likely to harm or kill individuals (Sandberg 2015, pers. comm.). Due to their speed, Sandberg (2015, pers. comm.) suggests immobilizing individuals by spraying them with soapy water and using a respirator to quickly collect them from the beat sheet or paper towel. A headlamp is recommended in dark, heavily vegetated areas and also on cloudy days to aid in collection (Sandberg 2015, pers. comm.).

Nymph: The mature nymph looks similar and is similar in size to the adult. It is distinguished from other species by its two pairs of cervical gills (in the “neck” area), which have three branches each that emerge laterally instead of from a common stalk (Baumann and Fiala 2001). Additionally, the sparse and mostly randomly spaced spines on the lateral margins of the femur (rather than in obvious row-like whorls) is diagnostic (Baumann and Fiala 2001).

While the microhabitat of N. wahkeena nymphs is not known, they are likely sprawlers—clingers, and cryptic, and concealed among the decaying leaf litter and other detritus that they feed on (reviewed in Merritt et al. 2008; reviewed in DeWalt 2009). They may be found by searching leaf packs and detritus covering seeps or looking within decaying plant material along the edges of seeps and springs (Wisseman 2015). Well-camouflaged nymphs are likely more difficult to find in the aquatic habitat compared to the more active adults. The microhabitat should be described in detail and photographed if nymphs are documented.

Additional characters used to identify the males, females, and nymphs of this species, as well as survey techniques are provided in the species fact sheet.

References: (survey protocol only)

Baumann, R.W. 2011. Personal communication with Sarah Foltz Jordan, the Xerces Society for Invertebrate Conservation. Richard Baumann, Brigham Young University, Provo, UT.

Baumann, R.W. 2020. Personal communication with Michele Blackburn, the Xerces Society for Invertebrate Conservation. Richard W. Baumann, Emeritus curator and collection manager of entomology, Brigham Young University, Provo, UT.

Baumann, R.W. and G.R. Fiala. 2001. Nanonemoura, a new stonefly genus from the Columbia River Gorge, Oregon (Plecoptera: Nemouridae). Western North American Naturalist 61(4): 403-408.

Craig, D.A. 1966. Techniques for rearing stream-dwelling organisms in the laboratory. Tuatara 14(2). Available online at http://www.nzetc.org/tm/scholarly/tei-Bio14Tuat02-t1-body-d1.html [last accessed 21 May 2020].

DeWalt, R.E. 2009. Plecoptera (Stoneflies). In: Encyclopedia of inland waters. Eds. G.E. Likens. Academic Press. pp. 415-422.

Fallon, C., E. Blevins, and R. Wisseman. 2016. Surveys to determine the status and distribution of three Columbia River Gorge endemic caddisfly and stonefly species: Farula constricta, Neothremma andersoni, and Nanonemoura wahkeena. Final report from the Xerces Society and Aquatic Biology Associates, Inc. to the Interagency Special Status/Sensitive Species Program (ISSSSP) and the Columbia River Gorge National Scenic Area (CRGNSA). Assistance Agreement L13AC00102, Modification 3. March 2016. 101 pp.

FS ISSSSP Database. 2019. FINAL Region 6 Regional Forester Special Status Species List, March 13, 2019.

Merritt, R.W., K.W. Cummins, and M.B. Berg. 2008. An Introduction to the aquatic insects of North America. Fourth Edition. Kendall/Hunt Publishing Co., Dubuque, Iowa. 989 pp.

Sandberg, J. 2015. Personal communication with Robert Wisseman, Aquatic Biology Associates, Inc. Corvallis, OR. John Sandberg, Taxonomist, Chico Aquatic Bioassessment Lab, California State University, Chico. 26 April.

Stewart, K.W. and B.P. Stark. 2008. Chapter 14. Plecoptera. pp. 311-384. In An introduction to the aquatic insects of North America. 4th edition. Merritt, R.W., K.W. Cummins, and M.B. Berg (eds). Kendall/Hunt Publishing Co., Dubuque, Iowa.

Triplehorn, C. and N. Johnson. 2005. Introduction to the Study of Insects. Thomson Brooks/Cole, Belmont, CA. 864 pp.

Voshell, Jr, J.R. 2002. A guide to common freshwater invertebrates of North America. McDonald and Woodward Publishing Co., Blacksburg, Virginia. 442 pp.

Wisseman, R. 2011. Personal communication with Sarah Foltz Jordan, the Xerces Society for Invertebrate Conservation. Robert Wisseman, Aquatic Biology Associates, Inc. Corvallis, OR.

Wisseman, R. 2015. Collecting sensitive aquatic invertebrate species in the Columbia River Gorge and adjacent Mount Hood area. Sensitive species workshop manual provided to participants of the Xerces/ISSSSP May 2015 training workshop. Unpublished document. 26 pp.

Wisseman, R. 2020. Personal communication with Candace Fallon and Michele Blackburn, the Xerces Society for Invertebrate Conservation. Robert Wisseman, Aquatic Biology Associates, Inc. Corvallis, OR. 1 June.

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