Margaritifera falcata - (Gould, 1850)
Western Pearlshell
Taxonomic Status: Accepted
Related ITIS Name(s): Margaritifera falcata (Gould, 1850) (TSN 80372)
French Common Names: mulette perlière de l'Ouest
Unique Identifier: ELEMENT_GLOBAL.2.107100
Element Code: IMBIV27020
Informal Taxonomy: Animals, Invertebrates - Mollusks - Freshwater Mussels
 
Kingdom Phylum Class Order Family Genus
Animalia Mollusca Bivalvia Unionoida Margaritiferidae Margaritifera
Genus Size: B - Very small genus (2-5 species)
Check this box to expand all report sections:
Concept Reference
Help
Concept Reference: Turgeon, D.D., J.F. Quinn, Jr., A.E. Bogan, E.V. Coan, F.G. Hochberg, W.G. Lyons, P.M. Mikkelsen, R.J. Neves, C.F.E. Roper, G. Rosenberg, B. Roth, A. Scheltema, F.G. Thompson, M. Vecchione, and J.D. Williams. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks. 2nd Edition. American Fisheries Society Special Publication 26, Bethesda, Maryland: 526 pp.
Concept Reference Code: B98TUR01EHUS
Name Used in Concept Reference: Margaritifera falcata
Taxonomic Comments: The family Margaritiferidae is recognized based on the recent work of Smith (1986) and Smith and Wall (1984). The monotypic genus Cumberlandia has generally has been classified in the family Margaritiferidae; however, preliminary analyses of electrophoretic data led Davis and Fuller (1981) to lump the margaritiferids with the Unionidae. Smith and Wall (1984) reinstated the Margaritiferidae to familial rank following and extensive examination and analysis of morphological characters. Some anatomical data on stomach anatomy (Smith, 1986) indicates Cumberlandia may require reduction to subgeneric level. This is supported by Davis and Fuller (1981), Ziuganov et al. (1994), Smith (2001), and Huff et al. (2004). Smith (2001) analyzied the taxonomic placement of the margaritiferid genera, recognizing Pseudunio, Margaritifera, and Margaritinopsis as valid based largely on morpological characters; with Margaritifera margaritifera the only species in the genus Margaritifera. Contrary to Smith (2001), Huff et al. (2004) investigated phylogenetic relationships using sequence data from five molecular markers and concluded recognition of of at least Margaritifera margaritifera, Margaritifera laevis, Margaritifera falcata, and Margaritifera auricularia with the following relationships: Cumberlandia + Margaritifera auricularia; Margaritifera falcata (Margaritifera marrianae + Margaritifera laevis); and to a lesser degree Dahurinaia dahurica + Margaritifera margaritifera. More recently, to monophyletic clades have been identified within Margaritiferidae based on COI data: one including M. margaritifera, M. dahurica, M. falcata, and M. laevis; and a second comprising M. auricularia and M. marocana (Araujo et al., 2009).
Conservation Status
Help

NatureServe Status

Global Status: G5
Global Status Last Reviewed: 22Sep2015
Global Status Last Changed: 22Sep2015
Ranking Methodology Used: Ranked by inspection
Rounded Global Status: G5 - Secure
Reasons: This species is widespread in geographic area and still maintains hundreds of occurrences with perhaps hundreds of thousands of individuals, but is declining, in terms of area occupied and number of sites and individuals, although the decline (probably 10-30%) may not be enough to warrant a higher ranking. Populations showing repeated reproduction (at least several age classes) are now the exception rather than the rule with some extirpations occurring, particularly at the central and southern edge of the species' range.
Nation: United States
National Status: N4 (16Jul1998)
Nation: Canada
National Status: N5 (01Aug2017)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Alaska (SNR), California (S1S2), Idaho (S2), Montana (S2), Nevada (S1), Oregon (S3), Utah (S1), Washington (S3S4), Wyoming (S3)
Canada British Columbia (S5)

Other Statuses

American Fisheries Society Status: Undetermined (01Jan1993)

NatureServe Global Conservation Status Factors

Range Extent: 20,000-200,000 square km (about 8000-80,000 square miles)
Range Extent Comments: Clarke (1981) lists former distribution as from California to the southern interior of British Columbia, to the Queen Charlotte Islands, and to Revillagigedo Island in Southeast Alaska. Once present from southern Alaska and British Columbia to central California, eastward to western Montana, western Wyoming, and northern Utah in the headwaters of the Missouri River (Nedeau et al., 2005), this species now persists only locally in parts of the Coeur d'Alene system, including the Coeur d'Alene River and St. Maries River (Frest and Johannes, 1995). In Oregon it historically occurred in the Klamath River system, rivers of the Coastal Range, and the main stem and tributaries of the Columbia River, including the Snake, Willamette, and Walla Walla Rivers (Brim Box et al., 2004). Hovingh (2004) found it in the upper Snake River in Wyoming and Idaho, upper Bear River in Wyoming, and Malheur Basin in Oregon. It has been recorded historically north to Naha Bay, Alaska (at 55 degrees North latitude); in the Fraser River; the Snake River in Idaho (Stanford, 1942); at Spokane, Yakima, Walla Walla, The Dalles, and Portland on the Columbia River; in Lake Crescent and the Chehalis River on the Olympic Peninsula; in North Creek (Sammamish River drainage), Whatcom Creek, Samish River, and Snoqualmie River in the Puget Sound lowlands; in the Deschutes River (at Bend, Oregon); in the Umpqua and Coos Rivers in Oregon; "Pinyon Canyon" [locality questionable] and the the Humboldt River, Nevada (UMMZ specimens as Margaritifera margaritifera); and in the Sacramento River, California (Dall, 1905; Henderson, 1929; 1936; Ingram, 1948; Clarke, 1981).

Area of Occupancy: 2,501 to >12,500 4-km2 grid cells
Area of Occupancy Comments:  

Number of Occurrences: 81 to >300
Number of Occurrences Comments: Hovingh (2004) found it in the upper Snake River in Wyoming and Idaho, upper Bear River in Wyoming, and Malheur Basin in Oregon. It was recently confirmed in the Middle Fork John Day River in Oregon (Brim Box et al., 2003; 2006). In Montana, it is found throughout the Missouri River headwaters, Kootenai River, Flathead River, Clark Fork River, Madison River, and Jefferson River (Gangloff and Gustafson, 2000) but Stagliano (2010) found 25 of the ~40 reported sites were extirpated or not viable and only 5 new viable sites were found. In Idaho, historical range includes sites in the Snake, Coeur d'Alene, Lost, and Salmon River drianages (Frest and Johannes, 1999) and populations persist in north Idaho in the Coeur d'Alene, St. Joe, and St. Maries Rivers (Stagliano et al., 2007). In central Idaho, populations with good viability occur in the Clearwater, Selway, Lochsa, Pahsimeroi, Lost, Salmon, and Little Salmon Rivers and in Hells Canyon while in south Idaho, populations are thought extant in the upper tributaries of the Snake River, including the Blackfoot River (Frest and Johannes, 1997). Lysne and Pierce (2009) found it rare in Crystal Creek-Spring Creek, Blaine Co., Idaho. Populations exist in the Lower Salmon River, Idaho (Vannote and Minshall, 1982; Davis and Muehlenbachs, 2001). It was believed extirpated in Utah until it was recently found in a tributary of the Weber River near Provo (C. Tait, USFS, pers. comm., 2010). Declines were noted in streams in western Washington (Hastie and Toy, 2008). Populations are also known from throughout California (see Howard and Cuffey, 2006), including the Pit River (Spring Rivers Ecological Sciences, 2001) and at least historically in the Truckee River (Murphy, 1942). A recent survey of 115 sites in the Plumas, Tahoe, and Eldorado National Forests plus Lake Tahoe Basin management unit found it in 15 sites (10 of 70+ streams) (Howard, 2008). Recently in California: McCloud River, Hat Creek, Pit and S Fork Pit River, Spanish Creek, Truckee River, Scott River, S Fork Eel River, Shasta River, San Antonio Creek, N Fork Stanislaus River, N, M, and S Fork Tuolumne River, S Fork American River, and M Fork Feather River (Howard, 2010). It is sparingly documented in southeast Alaska and questionably the Chukotski Peninsula in Russia (Baxter, 1987); including Revillagigedo Island and north to Naha Bay at 55 degrees latitude at Naha Bay, Alaska (Gustafson et al., 1997) and Prince of Wales Island (Metcalfe-Smith and Cudmore-Vokey, 2004). In Wyoming, Beetle (1989) lists occurrences in streams in Lincoln, Sublette, Teton, and Uinta Cos.; while Cvancara (2005) lists occurrences in the Snake and Missouri River drainages in Yellowstone National Park, the Snake River drainage in Teton, Lincoln, and Sublette Cos., and Bear River drainage in Lincoln and Uinta Co. Sites in the upper Columbia River in Washington still maintain viable populations (WA NHP, pers. comm., 2007). Taylor (1952) cites occurrences in the Snake Headwaters, Upper Snake (into Idaho), Upper Yellowstone, and Missouri headwaters (into Montana). In Canada, healthy populations occur in northern British Columbia and on southern Vancouver Island (Metcalfe-Smith and Cudmore-Vokey, 2004). In British Columbia, it occurs on the islands and as far east on the mainland as the Kettle River and as far north as the Babine Lake area at 55 deg latitude (Metcalfe-Smith and Cudmore-Vokey, 2004). Clarke (1981) cites northern distribution as southern interior of British Columbia, and farther north near the coast to Revillagigedo Island in southern Alaska.

Population Size: >1,000,000 individuals
Population Size Comments: A study by Howard and Cuffey (2006) of two populations in the south fork Eel and north fork Navarro Rivers in California indicated the Eel River population (>12,000 individuals) (Cuffey, 2002) is healthy with good viability while the Navarro River (~350 individuals) is not recruiting at all and is composed of mostly older individuals. Murphy (1942) cited over 20,000 individuals in a 3/4 mile channel of the Truckee River in California, but it is not known if this population still exists. In environments where host fish are abundant and human threats minimal, they can attain very high densities (> 300/ square meter), often carpeting the stream bottom.

Number of Occurrences with Good Viability/Integrity: Many to very many (41 to >125)
Viability/Integrity Comments: In Canada, healthy populations occur in northern British Columbia and on southern Vancouver Island (Metcalfe-Smith and Cudmore-Vokey, 2004). In California, this species is sparsely dispersed and not found in dense beds except 1 site on the South Fork Eel River (U. of California Natural Reserve system property) where thousands are packed into a 100 meter-long meander bend (Howard, 2010). A study by Howard and Cuffey (2006) of two populations in the south fork Eel and north fork Navarro Rivers in California indicated the Eel River population is healthy with good viability while the Navarro River is not recruiting at all and is composed of mostly older individuals. A population exists in the Upper Firehole River in Yellowstone National Park (Gangloff and Gustafson, 2000). Vannote and Minshall (1982) note the best developed communities in central Idaho are found in areas with large stable cobble and boulder channel gravels and such exemplary habitat exists in the Lower Salmon River.

Overall Threat Impact: High
Overall Threat Impact Comments: Extensive diversion of rivers for irrigation, hydroelectric, and water supply projects has much reduced the Washington, Oregon, Idaho, and California range of this species. Heavy nutrient enhancement, siltation, unstable substrate, or similar problems extirpate populations. Some sites in northern California have been impaired by a history of land uses in the watershed that has compromised its ecoloical integrity where sediment load and stream temperatures cause mussel populations to stop reproducing (Howard and Cuffey, 2006). Much of the middle Snake River in Idaho is rapidly becoming eutrofied, due to agricultural runoff, fish farms, and urbanization along the river corridor. Much of the river is impounded behind a series of small dams; this is also detrimental for cold-water species such as this taxon. Fine sediment influx, generally from the same causes, is also a major problem. A recent (1994) landslide impacted some of the historic sites. In the lower Columbia River region, threats include impoundments; continued siltation and other impacts on the few remaining sites with habitat characteristics approximating pre-impoundment conditions on the lower Columbia; harbor and channel "improvements" in the vicinity of The Dalles and John Day Dam; nutrient enrichment of the lower Columbia due to agricultural run-off (Frest and Johannes, 1995). In a study of two populations in northern California, Howard and Cuffey (2006) postulated that high flows may be necessary periodically (over the long-term as this species can live over 100 years) to remove silt and biological deposits that accumulate in mussel aggregations. These accumulations can be particularly problematic in low-discharge refuges and reduce survival and scouring floods may be necessary to maintain suitable mussel habitat for growth and reproduction.

Short-term Trend: Decline of 10-50%
Short-term Trend Comments: The taxon is declining, in terms of area occupied and number of sites and individuals (Frest and Johannes, 1995; Hovingh, 2004) but the degree of the decline is unclear (possibly 10-30%). This species has likely recently been extirpated from the Umatilla River in Oregon (Brim Box et al., 2003). In Montana, many populations are declining with previously reported mussel beds from the Blackfoot, Big Hole, Bitterroot, Clark Fork, and Middle Snake Rivers are extirpated (Stagliano et al., 2007); with 25 of ~40 originally reported sites not viable or extirpated and only 5 new viable sites found (Stagliano, 2010). Significant local declines and a few extirpations have occurred in Washington (WA NHP, pers. comm., 2009) although it is still widespread in the state. Howard (2008) found reduction in both number of sites and number of individuals at remaining sites for historically known populations in the Plumas, Tahoe, and Eldorado National Forests and the Lake Tahoe Management Basin in California. It appears all mussels are extirpated from southern California, south of Santa Cruz (Howard, 2010). Surveys of populations in western Washington in 1995 and again in 2006 revealed significant declines in mussel numbers and density and a large proportion of empty shells plus a disproportionate loss of large, old mussels (Hastie and Toy, 2008).

Long-term Trend: Decline of 30-50%
Long-term Trend Comments: This species is now extirpated along much of the mainstem of the Snake River and Columbia River of Oregon and Washington, and remnant populations show few signs of recent reproduction (Nedeau et al., 2005). All 11 localities (perhaps 9 populations) in Utah have been extirpated except one (Weber River) recently rediscovered (C. Tait, USFS, pers. comm., 2010); it formerly occurred in the northern third of the state and into Nevada (Oliver and Bosworth, 1999).

Intrinsic Vulnerability: Moderately vulnerable to not intrinsically vulnerable.
Intrinsic Vulnerability Comments: The species is fairly resistant to non-destructive intrusion. Although widespread, in range, populations are in decline except in the northern limits of its range. Surveys of populations in western Washington in 1995 and again in 2006 revealed significant declines in mussel numbers and density and a large proportion of empty shells plus a disproportionate loss of large, old mussels; indicating recruitmene problems possibly due to habitat degradation following stream corridor colonization by beavers and/or lack of migratory host fish (Hastie and Toy, 2008).

Environmental Specificity: Unknown

Other NatureServe Conservation Status Information

Inventory Needs: Further work needs to be done to document range changes, particularly the status of interior populations (Frest & Johannes 1995).

Distribution
Help
Global Range: (20,000-200,000 square km (about 8000-80,000 square miles)) Clarke (1981) lists former distribution as from California to the southern interior of British Columbia, to the Queen Charlotte Islands, and to Revillagigedo Island in Southeast Alaska. Once present from southern Alaska and British Columbia to central California, eastward to western Montana, western Wyoming, and northern Utah in the headwaters of the Missouri River (Nedeau et al., 2005), this species now persists only locally in parts of the Coeur d'Alene system, including the Coeur d'Alene River and St. Maries River (Frest and Johannes, 1995). In Oregon it historically occurred in the Klamath River system, rivers of the Coastal Range, and the main stem and tributaries of the Columbia River, including the Snake, Willamette, and Walla Walla Rivers (Brim Box et al., 2004). Hovingh (2004) found it in the upper Snake River in Wyoming and Idaho, upper Bear River in Wyoming, and Malheur Basin in Oregon. It has been recorded historically north to Naha Bay, Alaska (at 55 degrees North latitude); in the Fraser River; the Snake River in Idaho (Stanford, 1942); at Spokane, Yakima, Walla Walla, The Dalles, and Portland on the Columbia River; in Lake Crescent and the Chehalis River on the Olympic Peninsula; in North Creek (Sammamish River drainage), Whatcom Creek, Samish River, and Snoqualmie River in the Puget Sound lowlands; in the Deschutes River (at Bend, Oregon); in the Umpqua and Coos Rivers in Oregon; "Pinyon Canyon" [locality questionable] and the the Humboldt River, Nevada (UMMZ specimens as Margaritifera margaritifera); and in the Sacramento River, California (Dall, 1905; Henderson, 1929; 1936; Ingram, 1948; Clarke, 1981).

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map
Endemism: occurs (regularly, as a native taxon) in multiple nations

U.S. & Canada State/Province Distribution
United States AK, CA, ID, MT, NV, OR, UT, WA, WY
Canada BC

Range Map
No map available.


U.S. Distribution by County Help
State County Name (FIPS Code)
AK Ketchikan Gateway (02130), Prince of Wales-Outer Ketchikan (CA) (02201), Skagway-Hoonah-Angoon (CA) (02232)
CA Calaveras (06009), Del Norte (06015)*, El Dorado (06017), Humboldt (06023), Kern (06029), Mendocino (06045), Modoc (06049), Nevada (06057), Placer (06061), Plumas (06063), Santa Cruz (06087)*, Shasta (06089), Sierra (06091), Siskiyou (06093), Trinity (06105), Tulare (06107)*, Tuolumne (06109), Yuba (06115)
ID Bear Lake (16007), Blaine (16013), Caribou (16029), Clearwater (16035), Custer (16037), Elmore (16039), Fremont (16043), Gooding (16047), Idaho (16049), Jerome (16053), Latah (16057), Lemhi (16059), Madison (16065), Nez Perce (16069), Owyhee (16073), Shoshone (16079), Teton (16081), Twin Falls (16083), Valley (16085)
MT Beaverhead (30001), Broadwater (30007), Cascade (30013), Deer Lodge (30023), Gallatin (30031), Granite (30039), Jefferson (30043), Lake (30047), Lewis and Clark (30049), Lincoln (30053), Madison (30057), Meagher (30059), Missoula (30063), Powell (30077), Ravalli (30081), Sanders (30089), Silver Bow (30093)
OR Benton (41003), Clackamas (41005), Clatsop (41007), Columbia (41009), Deschutes (41017), Douglas (41019), Grant (41023), Harney (41025), Hood River (41027), Jackson (41029), Jefferson (41031)*, Klamath (41035), Lake (41037), Lincoln (41041)*, Linn (41043), Marion (41047), Polk (41053), Sherman (41055), Umatilla (41059), Union (41061), Wallowa (41063), Wasco (41065), Washington (41067), Yamhill (41071)
UT Box Elder (49003), Davis (49011)*, Morgan (49029)*, Rich (49033)*, Salt Lake (49035)*, Summit (49043)
WA Chelan (53007), Clallam (53009), Clark (53011), Columbia (53013), Ferry (53019), Grays Harbor (53027), Jefferson (53031), King (53033), Kittitas (53037), Lewis (53041), Mason (53045), Okanogan (53047), Pacific (53049), Pierce (53053), Skagit (53057), Snohomish (53061), Spokane (53063), Stevens (53065), Thurston (53067), Whatcom (53073), Yakima (53077)
WY Lincoln (56023), Sublette (56035), Teton (56039), Uinta (56041)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
10 Red Rock (10020001)+, Beaverhead (10020002)+, Ruby (10020003)+, Big Hole (10020004)+, Jefferson (10020005)+, Boulder (10020006)+, Madison (10020007)+, Gallatin (10020008)+, Upper Missouri (10030101)+, Upper Missouri-Dearborn (10030102)+, Smith (10030103)+
14 Blacks Fork (14040107)+
16 Upper Bear (16010101)+, Central Bear (16010102)+, Bear Lake (16010201)+, Upper Weber (16020101)+, Lower Weber (16020102)+*, Jordan (16020204)+*, Truckee (16050102)+
17 Upper Kootenai (17010101)+, Fisher (17010102)+, Yaak (17010103)+, Lower Kootenai (17010104)+, Upper Clark Fork (17010201)+, Flint-Rock (17010202)+, Blackfoot (17010203)+, Middle Clark Fork (17010204)+, Bitterroot (17010205)+, Lower Flathead (17010212)+, Lower Clark Fork (17010213)+, St. Joe (17010304)+, Upper Spokane (17010305)+*, Hangman (17010306)+, Lower Spokane (17010307)+, Little Spokane (17010308)+, Kettle (17020002)+, Colville (17020003)+, Sanpoil (17020004)+, Okanogan (17020006)+, Similkameen (17020007)+, Methow (17020008)+, Wenatchee (17020011)+, Upper Yakima (17030001)+, Naches (17030002)+, Snake headwaters (17040101)+, Gros Ventre (17040102)+, Greys-Hobock (17040103)+, Salt (17040105)+, Lower Henrys (17040203)+, Teton (17040204)+, Blackfoot (17040207)+, Raft (17040210)+, Upper Snake-Rock (17040212)+, Little Wood (17040221)+, C. J. Idaho (17050101)+, Middle Snake-Succor (17050103)+, Jordan (17050108)+, Upper Malheur (17050116)+, Hells Canyon (17060101)+, Lower Snake-Asotin (17060103)+, Upper Grande Ronde (17060104)+, Lower Grande Ronde (17060106)+, Lower Snake-Tucannon (17060107)+, Upper Salmon (17060201)+, Pahsimeroi (17060202)+, Middle Salmon-Panther (17060203)+, South Fork Salmon (17060208)+, Lower Salmon (17060209)+, Lower Selway (17060302)+, Lochsa (17060303)+, South Fork Clearwater (17060305)+, Clearwater (17060306)+, Upper North Fork Clearwater (17060307)+, Lower North Fork Clearwater (17060308)+, Umatilla (17070103)+, Middle Columbia-Hood (17070105)+, Klickitat (17070106)+, Middle Fork John Day (17070203)+, Upper Deschutes (17070301)+, Lower Deschutes (17070306)+, Lower Columbia-Sandy (17080001)+, Lewis (17080002)+, Lower Cowlitz (17080005)+*, Upper Willamette (17090003)+, North Santiam (17090005)+, South Santiam (17090006)+, Middle Willamette (17090007)+, Molalla-Pudding (17090009)+, Tualatin (17090010)+, Lower Willamette (17090012)+, Hoh-Quillayute (17100101)+, Queets-Quinault (17100102)+, Upper Chehalis (17100103)+, Lower Chehalis (17100104)+, Willapa Bay (17100106)+, Nehalem (17100202)+, Siletz-Yaquina (17100204)+*, Alsea (17100205)+*, North Umpqua (17100301)+, South Umpqua (17100302)+, Upper Rogue (17100307)+, Strait of Georgia (17110002)+, Nooksack (17110004)+, Stillaguamish (17110008)+, Skykomish (17110009)+, Snoqualmie (17110010)+, Snohomish (17110011)+, Lake Washington (17110012)+, Duwamish (17110013)+, Nisqually (17110015)+, Deschutes (17110016)+*, Puget Sound (17110019)+, Dungeness-Elwha (17110020)+, Crescent-Hoko (17110021)+, Donner Und Blitzen (17120003)+
18 Smith (18010101)+*, South Fork Eel (18010106)+, Williamson (18010201)+, Sprague (18010202)+, Upper Klamath (18010206)+, Shasta (18010207)+, Scott (18010208)+, Lower Klamath (18010209)+, Trinity (18010211)+, Upper Pit (18020002)+, Lower Pit (18020003)+, Mccloud (18020004)+, Sacramento headwaters (18020005)+, North Fork Feather (18020121)+, East Branch North Fork Feather (18020122)+, Middle Fork Feather (18020123)+, Upper Yuba (18020125)+, North Fork American (18020128)+, South Fork American (18020129)+, Clear Creek-Sacramento River (18020154)+*, South Fork Kern (18030002)+*, Upper Poso (18030004)+, Upper Tuolumne (18040009)+, Upper Stanislaus (18040010)+, Upper Calaveras (18040011)+, San Lorenzo-Soquel (18060001)+*
19 Ketchikan (19010102)+, Prince of Wales (19010103)+, Admiralty Island (19010204)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
Help
Basic Description: A freshwater mussel with purple nacre (Frest & Johannes 1995).
Reproduction Comments: Glochidial host fish include chinook salmon (Oncorhynchus tschawytscha), rainbow trout (Oncorhynchus mykiss), coho (Oncorhynchus kisutch), cutthroat trout (Salmo clarki), and steelhead trout (Salmo gairdneri) (Fuller, 1974; Karnat and Millemann, 1978).
Habitat Type: Freshwater
Non-Migrant: N
Locally Migrant: N
Long Distance Migrant: N
Riverine Habitat(s): BIG RIVER, CREEK, MEDIUM RIVER, Moderate gradient
Special Habitat Factors: Benthic
Habitat Comments: This species prefers cold clean creeks and rivers that support salmonid populations. It can inhabit headwater streams less than a few feet wide, but is more common in larger rivers. It can even be found in some irrigation ditches in Oregon. Sand, gravel, and cobble are preferred substrates, especially in stable areas of the streambed. Large boulders hellp create stable enviroments by anchoring the substrate and creating a refuge from strong currents on the downstream side. (Nedeau et al., 2005). Vannote and Minshall (1982) note the best developed communities in central Idaho are found in areas with large stable cobble and boulder channel gravels.
Economic Attributes Not yet assessed
Help
Management Summary Not yet assessed
Help
Population/Occurrence Delineation
Help
Group Name: Freshwater Mussels

Use Class: Not applicable
Minimum Criteria for an Occurrence: Occurrences are based on some evidence of historical or current presence of single or multiple specimens, including live specimens or recently dead shells (i.e., soft tissue still attached and/or nacre still glossy and iridescent without signs of external weathering or staining), at a given location with potentially recurring existence. Weathered shells constitute a historic occurrence. Evidence is derived from reliable published observation or collection data; unpublished, though documented (i.e. government or agency reports, web sites, etc.) observation or collection data; or museum specimen information.
Mapping Guidance: Based on the separation distances outlined herein, for freshwater mussels in STANDING WATER (or backwater areas of flowing water such as oxbows and sloughs), all standing water bodies with either (1) greater than 2 km linear distance of unsuitable habitat between (i.e. lotic connections), or (2) more than 10 km of apparently unoccupied though suitable habitat (including lentic shoreline, linear distance across water bodies, and lentic water bodies with proper lotic connections), are considered separate element occurrences. Only the largest standing water bodies (with 20 km linear shoreline or greater) may have greater than one element occurrence within each. Multiple collection or observation locations in one lake, for example, would only constitute multiple occurrences in the largest lakes, and only then if there was some likelihood that unsurveyed areas between collections did not contain the element.

For freshwater mussels in FLOWING WATER conditions, occurrences are separated by a distance of more than 2 stream km of unsuitable habitat, or a distance of more than 10 stream km of apparently unoccupied though suitable habitat. Standing water between occurrences is considered suitable habitat when calculating separation distance for flowing water mussel species unless dispersal barriers (see Separation Barriers) are in place.

Several mussel species in North America occur in both standing and flowing water (see Specs Notes). Calculation of separation distance and determination of separation barriers for these taxa should take into account the environment in which the element was collected. Juvenile mussels do not follow this pattern and juveniles are typically missed by most standard sampling methods (Hastie and Cosgrove, 2002; Neves and Widlak, 1987), therefore juvenile movement is not considered when calculating separation distance.

Separation Barriers: Separation barriers within standing water bodies are based solely on separation distance (see Separation Distance-suitable, below). Separation barriers between standing water bodies and within flowing water systems include lack of lotic connections, natural barriers such as upland habitat, absence of appropriate species specific fish hosts, water depth greater than 10 meters (Cvancara, 1972; Moyle and Bacon, 1969) or anthropogenic barriers to water flow such as dams or other impoundments and high waterfalls.
Separation Distance for Unsuitable Habitat: 2 km
Separation Distance for Suitable Habitat: 10 km
Alternate Separation Procedure: None
Separation Justification: Adult freshwater mussels are largely sedentary spending their entire lives very near to the place where they first successfully settled (Coker et al., 1921; Watters, 1992). Strayer (1999) demonstrated in field trials that mussels in streams occur chiefly in flow refuges, or relatively stable areas that displayed little movement of particles during flood events. Flow refuges conceivably allow relatively immobile mussels to remain in the same general location throughout their entire lives. Movement occurs with the impetus of some stimulus (nearby water disturbance, physical removal from the water such as during collection, exposure conditions during low water, seasonal temperature change or associated diurnal cycles) and during spawning. Movement is confined to either vertical movement burrowing deeper into sediments though rarely completely beneath the surface, or horizontal movement in a distinct path often away from the area of stimulus. Vertical movement is generally seasonal with rapid descent into the sediment in autumn and gradual reappearance at the surface during spring (Amyot and Downing, 1991; 1997). Horizontal movement is generally on the order of a few meters at most and is associated with day length and during times of spawning (Amyot and Downing, 1997). Such locomotion plays little, if any, part in the distribution of freshwater mussels as these limited movements are not dispersal mechanisms. Dispersal patterns are largely speculative but have been attributed to stream size and surface geology (Strayer, 1983; Strayer and Ralley, 1993; van der Schalie, 1938), utilization of flow refuges during flood stages (Strayer, 1999), and patterns of host fish distribution during spawning periods (Haag and Warren, 1998; Watters, 1992). Lee and DeAngelis (1997) modeled the dispersal of freshwater into unoccupied habitats as a traveling wave front with a velocity ranging from 0.87 to 2.47 km/year (depending on mussel life span) with increase in glochidial attachment rate to fish having no effect on wave velocity.

Nearly all mussels require a host or hosts during the parasitic larval portion of their life cycle. Hosts are usually fish, but a few exceptional species utilize amphibians as hosts (Van Snik Gray et al., 2002; Howard, 1915) or may metamorphose without a host (Allen, 1924; Barfield et al., 1998; Lefevre and Curtis, 1911; 1912). Haag and Warren (1998) found that densities of host generalist mussels (using a variety of hosts from many different families) and displaying host specialists (using a small number of hosts usually in the same family but mussel females have behavioral modifications to attract hosts to the gravid female) were independent of the densities of their hosts. Densities of non-displaying host specialist mussels (using a small number of hosts usually in the same family but without host-attracting behavior) were correlated positively with densities of their hosts. Upstream dispersal of host fish for non-displaying host specialist mussels could, theoretically, transport mussel larvae (glochidia) over long distances through unsuitable habitat, but it is unlikely that this occurs very often. D. Strayer (personal communication) suggested a distance of at least 10 km, but a greater distance between occurrences may be necessary to constitute genetic separation of populations. As such, separation distance is based on a set, though arbitrary, distance between two known points of occurrence.

Date: 18Oct2004
Author: Cordeiro, J.
Notes: Contact Jay Cordeiro (jay_cordeiro@natureserve.org) for a complete list of freshwater mussel taxa sorted by flow regime.
Population/Occurrence Viability
Help
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
Help
Authors/Contributors
Help
NatureServe Conservation Status Factors Edition Date: 16Mar2009
NatureServe Conservation Status Factors Author: Cordeiro, J. (2009); K. Jurist (1996)
Element Ecology & Life History Edition Date: 02Nov2006
Element Ecology & Life History Author(s): Cordeiro, J.

Zoological data developed by NatureServe and its network of natural heritage programs (see Local Programs) and other contributors and cooperators (see Sources).

References
Help
  • Andersen, M.D. 2011. HUC10-based species range maps. Prepared by Wyoming Natural Diversity Database for use in the pilot WISDOM application operational from inception to yet-to-be-determined date of update of tool.

  • Araujo, R., C. Toledo, D. Van Damme, M. Ghamizi, and A. Machordom. 2009. Margaritifera marocana (Pallary, 1918): A valid species inhabiting Moroccan rivers. Journal of Molluscan Studies 75:95-101.

  • Baxter, R. 1987. Mollusks of Alaska: a listing of all mollusks, freshwater, terrestrial, and marine reported from the State of Alaska, with locations of the species types, maximum sizes and marine depths inhabited. Shells and Sea Life, Bayside, California. 163 pp.

  • Burch, J. B. 1975. Freshwater Unionacean clams (Mollusca: Pelecypoda) of North America. Environmental Protection Agency, Biota of Freshwater Ecosystems Identification Manual No. 11. 176 pp.

  • Clarke, A. H. 1981. The freshwater molluscs of Canada. National Museum of Natural Sciences, National Museums of Canada, Ottawa. 446 pp.

  • Clarke, A.H. 1981a. The Freshwater Molluscs of Canada. National Museum of Natural Sciences, National Museums of Canada, D.W. Friesen and Sons, Ltd.: Ottawa, Canada. 446 pp.

  • Dall, W.H. 1905. Land and freshwater mollusks of Alaska and adjoining regions. Harriman Alaska Expedition Report 13: 1-171.

  • Davis, G.M. and S.L.H. Fuller. 1981. Genetic relationships among recent Unionacea (Bivalvia) of North America. Malacologia, 20(2): 217-253.

  • Davis, L.G. and K. Muehlenbachs. 2001. A late Pleistocene to Holocene record of precipitation reflected in Margaritifera falcata shell O18O from three archaeological sites in the lower Salmon River Canyon, Idaho. Journal of Archaeological Science 28:291-303.

  • Frest, T. J. and E. J. Johannes. 1995. Interior Columbia Basin mollusk species of special concern. Final report to the Interior Columbia Basin Ecosystem Management Project, Walla Walla, WA. Contract #43-0E00-4-9112. 274 pp. plus appendices.

  • Frest, T.J. and E.J. Johannes. 1995c. Interior Columbia Basin mollusk species of special concern. Final Report (contract #43-0E00-4-9112) prepared for Interior Columbia Basin Ecosystem Management Project. Deixis Consultants, Seattle, Washington. 274 pp. + tabs., figs.

  • Fuller, S.L.H. 1974. Chapter 8: Clams and mussels (Mollusca: Bivalvia). Pages 215-273 in: C.W. Hart, Jr. and S.L.H. Fuller (eds.) Pollution Ecology of Freshwater Invertebrates. Academic Press: New York. 389 pp.

  • Gustafson, R.G. and E.M. Iwamoto. 2005. A DNA-based indentification key to Pacific Northwest freshwater mussel glochidia: Importance to salmonid and mussel conservation. Northwest Science 79(4): 233-245.

  • Hastie, L.C. and K.A. Toy. 2008. Change in density, age structure and age-specific mortality in two western pearlshell (Margaritifera falcata) populations in Washington (1995-2006). Aquatic Conservation: Marien and Freshwater Ecosystems 18:671-678.

  • Henderson, J. 1936. The non-marine Mollusca of Oregon and Washington- supplement. University of Colorado Studies, 23(4): 251-280.

  • Henderson, J.B. 1929a. Non-marine mollusca of Oregon and Washington. University of Colorado Studies 17(2): 47-190.

  • Howard, A.D. 1915. Some exceptional cases of breeding among the Unionidae. The Nautilus 29:4-11.

  • Howard, J. 2010. Sensitive freshwater mussel surveys in the Pacific southwest region: Assessment of conservation status. Report prepared for USDA Forest Service, Vallejo, California. 57 pp.

  • Howard, J.K. 2008. Strategic inventory of freshwater mussels in the northern Sierra Nevada province. Repoort prepared by Western Mollusk Sciences (San Francisco, California) for USDA Forest Service, Vallejo, California. 45 pp. + app.

  • Huff, S.W., D. Campbell, D.L. Gustafson, C. Lydeard, C.R. Altaba, and G. Giribet. 2004. Investigations into the phylogenetic relationships of freshwater pearl mussels (Bivalvia: Margaritiferidae) based on molecular data: implications for their taxonomy and biogeography. Journal of Molluscan Studies, 70: 379-388.

  • Ingram, W.M. 1948. The Larger Freshwater Clams of California, Oregon and Washington. Journal of Entomology and Zoology. 40:72-92.

  • Ingram, W.M. 1948. The larger freshwater clams of California, Oregon and Washington. Journal of Entomology and Zoology 40:72-92.

  • Karnat, D. and R.E. Millemann, R.E. 1978. Glochidiosis of salmonid fishes. III. Comparative susceptibility to natural infection with Margaritifera margaritifera (L.) (Pelecypoda: Margaritanidae). The Journal of Parasitology 64(4): 528-537.

  • Lefevre, G. and W.T. Curtis. 1912. Studies on the reproduction and artificial propogation of fresh-water mussels. Bulletin of the Bureau of Fisheries 30:102-201.

  • Lysne, S. 2009. A Guide to Southern Idaho's Freshwater Mollusks. U.S. Fish and Wildlife Service. 43 pp.

  • Lysne, S.J. and R. Pierce. 2009. Mollusk survey of Crystal Creek-Spring Creek Ranches, Blaine County, Idaho, USA. Ellipsaria 11(1):20.

  • Moyle, P. and J. Bacon. 1969. Distribution and abundance of molluscs in a fresh water environment. Journal of the Minnesota Academy of Science 35(2/3):82-85.

  • Nedeau, E., A.K. Smith, and J. Stone. 2005. Freshwater Mussels of the Pacific Northwest. Pacific Northwest Native Freshwater Mussel Workgroup, Vancouver, Washington. 45 pp.

  • Nedeau, E., A.K. Smith, and J. Stone. [2005]. Freshwater Mussels of the Pacific Northwest. Pacific Northwest Native Freshwater Mussel Workgroup, Vancouver, Washington. 45 pp.

  • Pilsbry, H. A. 1939-1948. Land Mollusca of North America (north of Mexico). Academy of Natural Sciences, Philadelphia, Mon. 3, 2 vols., 4 pts.

  • Smith, D.G. 1986. The stomach anatomy of some eastern North American Margaritiferidae (Unionoida: Unionacea). American Malacological Bulletin, 4(1): 13-19.

  • Smith, D.G. 2001. Systematic and distribution of the recent Margaritiferidae. Pages 33-49 in G. Bauer and K. Wachter (eds.) Ecology and Evolution of the Freshwater Mussels Unionoida. Springer-Verlag: Berlin, Germany.

  • Smith, D.G. and W.P. Wall. 1984. The Margaritiferidae reinstated: a reply to Davis and Fuller (1981), "genetic relationships among recent Unionacea of North America." Occasional Papers on Mollusks, 4: 321-330.

  • Strayer, D. 1983. The effects of surface geology and stream size on freshwater mussel (Bivalvia, Unionidae) distribution in southeastern Michigan, U.S.A. Freshwater Biology 13:253-264.

  • Strayer, D.L. 1999a. Use of flow refuges by unionid mussels in rivers. Journal of the North American Benthological Society 18(4):468-476.

  • Strayer, D.L. and J. Ralley. 1993. Microhabitat use by an assemblage of stream-dwelling unionaceans (Bivalvia) including two rare species of Alasmidonta. Journal of the North American Benthological Society 12(3):247-258.

  • Turgeon, D.D., J.F. Quinn, Jr., A.E. Bogan, E.V. Coan, F.G. Hochberg, W.G. Lyons, P.M. Mikkelsen, R.J. Neves, C.F.E. Roper, G. Rosenberg, B. Roth, A. Scheltema, F.G. Thompson, M. Vecchione, and J.D. Williams. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks. 2nd Edition. American Fisheries Society Special Publication 26, Bethesda, Maryland: 526 pp.

  • Van der Schalie, H. 1938a. The naiad fauna of the Huron River in southeastern Michigan. Miscellaneous Publication of the Museum of Zoology, University of Michigan 40:7-78.

  • Vannote, R.L. and G.W. Minshall. 1982. Fluvial processes and local lithology controlling abundance, structure, and composition of mussel beds. Proceedings of the National Academy of Sciences, 79: 4103-4107.

  • Watters, G.T. 1992a. Unionids, fishes, and the species-area curve. Journal of Biogeography 19:481-490.

  • Williams, J. D., A. E. Bogan, R. S. Butler, K. S. Cummings, J. T. Garner, J. L. Harris, N. A. Johnson, and G. T. Watters. 2017. A revised list of the freshwater mussels (Mollusca: Bivalvia: Unionida) of the United States and Canada. Freshwater Mollusk Biology and Conservation 20:33-58.

  • Williams, J. D., M. L. Warren, Jr., K. S. Cummings, J. L. Harris and R. J. Neves. 1993. Conservation status of freshwater mussels of the United States and Canada. Fisheries 18(9):6-22.

  • Williams, J.D., M.L. Warren, Jr., K.S. Cummings, J.L. Harris, and R.J. Neves. 1993b. Conservation status of freshwater mussels of the United States and Canada. Fisheries 18(9): 6-22.

  • Ziuganov, V., A. Zotin, L. Nezlin, and V. Tretiakov. 1994. The Freshwater Pearl Mussels and Their Relationships with Salmonid Fish. VNIRO Publishing House: Moscow, Russia. 104 pp.

References for Watershed Distribution Map
  • Beetle, D. E. 1989. Checklist of recent Mollusca of Wyoming, U.S.A. The Great Basin Naturalist 49(4):637-645.

  • Brim Box, J., D. Wolf, J. Howard, C. O'Brien, D. Nez, and D. Close. 2003. The distribution and status of freshwater mussels in the Umatilla River system. Report project no. 2002-037-00 prepared for the U.S. Department of Energy, Bonneville Power Administration, Division of Fish and Wildlife, Portland, Oregon. 72 pp.

  • Brim Box, J., J. Howard, D. Wolf, C. O'Brien, D. Nez, and D. Close. 2006. Freshwater mussels (Bivalvia: Unionoida) of the Umatilla and Middle Fork John Day Rivers in eastern Oregon. Northwest Science, 80(2): 95-107.

  • Cuffey, K.M. 2002. Freshwater mussels in a California north coast range river: occurrence, distribution, and controls. Technical Research Report University of California Water Resources Center, Project W-933, Berkeley, California. 21 pp.

  • Cvancara, A.M. 2005. Illustrated key to Wyoming's freshwater mussels. A.M. Cvancara: Casper, Wyoming. 5 pp.

  • Frest, T. J. 1999. A Review of the land and freshwater Mollusks of Idaho. Final report to the Idaho Conservation Data Center, Idaho Department of Fish and Game, 600 South Walnut, P.O. Box 25, Boise, Idaho 83707. 281 pp. plus appendices.

  • Frest, T.J. and E.J. Johannes. 1995a. Freshwater Mollusks of the Upper Klamath Drainage, Oregon. Final report to the Oregon Natural Heritage Program, 821 SE 14th, Portland, Oregon 97214. Contract #ORFO 092094. 68 pp. plus appendices.

  • Gangloff, M.M. and D.L. Gustafson. 2000. Freshwater mussels (Bivalvia: Unionoida) of Montana. Central Plains Archaeology, 8(1): 121-130.

  • Gustafson, R. G., T. C. Wainwright, G. A. Winans, F. W. Waknitz, L. T. Parker, and R. S. Waples. 1997. Status review of sockeye salmon from Washington and Oregon. U.S. Department of Commerce, NOAA Technical Memo. NMFS-NWFSC-33, 282 pp.

  • Hovingh, P. 2004. Intermountain freshwater mollusks, USA (Margaritifera, Anodonta, Gonidea, Valvata, Ferrissia): geography, conservation, and fish management implications. Monographs of the Western North American Naturalist, 2: 109-135.

  • Howard, J.K. and K.M. Cuffey. 2006. Factors controlling the age structure of Margaritifera falcata in 2 northern California streams. Journal of the North American Benthological Society, 25(3): 677-690.

  • Metcalfe-Smith, J.L. and B. Cudmore-Vokey. 2004. National general status assessment of freshwater mussels (Unionacea). National Water Research Institute / NWRI Contribution No. 04-027. Environment Canada, March 2004. Paginated separately.

  • Murphy, G. 1942. Relationship of the fresh-water mussel to trout in the Truckee River. California Fish and Game, 28(2): 89-102.

  • Oliver, G.V. and W.R. Bosworth, III. 1999. Rare, imperiled, and recently extinct or extirpated mollusks of Utah. Report ot the Utah Division of Wildlife Resources, Publication Number 99-29, Salt Lake City, Utah. 231 pp.

  • Spring Rivers Ecological Sciences. 2001. River corridor habitat mapping and biota surveys, with emphasis on special-status species, for Pacific Gas and Electric Company's Pit 3, 4, and 5 hydroelectric project (FERC No. 233). Draft report prepared for the Pacific Gas and Electric Company. Spring Rivers Ecological Sciences, Cassel, California.

  • Stagliano, D.M., G.M. Stephens, and W.R. Bosworth. 2007. Aquatic invertebrate species of concern on USFS Northern Region lands. Report prepared for USDA Forest Service, Northern Region, Missoula, Montana. Montana Natural Heritage Program, Helena, Montana and Idaho Conservation Data Center, Boise, Idaho. Agreement number 05-CS-11015600-036. 95 pp. + app.

  • Taylor, D.W. 1952. Notes on the freshwater mollusks of Yellowstone Park, Wyoming. Leaflets in Malacology, 1(9): 43-49.

  • Taylor, D.W. 1981b. Freshwater mollusks of California: a distributional checklist. California Fish and Game 67(3):140-163.

  • University of Michigan Museum of Zoology (UMMZ) Mollusks Department collections. Ann Arbor, MI.

Use Guidelines & Citation

Use Guidelines and Citation

The Small Print: Trademark, Copyright, Citation Guidelines, Restrictions on Use, and Information Disclaimer.

Note: All species and ecological community data presented in NatureServe Explorer at http://explorer.natureserve.org were updated to be current with NatureServe's central databases as of March 2019.
Note: This report was printed on

Trademark Notice: "NatureServe", NatureServe Explorer, The NatureServe logo, and all other names of NatureServe programs referenced herein are trademarks of NatureServe. Any other product or company names mentioned herein are the trademarks of their respective owners.

Copyright Notice: Copyright © 2019 NatureServe, 2511 Richmond (Jefferson Davis) Highway, Suite 930, Arlington, VA 22202, U.S.A. All Rights Reserved. Each document delivered from this server or web site may contain other proprietary notices and copyright information relating to that document. The following citation should be used in any published materials which reference the web site.

Citation for data on website including State Distribution, Watershed, and Reptile Range maps:
NatureServe. 2019. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://explorer.natureserve.org. (Accessed:

Citation for Bird Range Maps of North America:
Ridgely, R.S., T.F. Allnutt, T. Brooks, D.K. McNicol, D.W. Mehlman, B.E. Young, and J.R. Zook. 2003. Digital Distribution Maps of the Birds of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Bird Range Maps of North America:
"Data provided by NatureServe in collaboration with Robert Ridgely, James Zook, The Nature Conservancy - Migratory Bird Program, Conservation International - CABS, World Wildlife Fund - US, and Environment Canada - WILDSPACE."

Citation for Mammal Range Maps of North America:
Patterson, B.D., G. Ceballos, W. Sechrest, M.F. Tognelli, T. Brooks, L. Luna, P. Ortega, I. Salazar, and B.E. Young. 2003. Digital Distribution Maps of the Mammals of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Mammal Range Maps of North America:
"Data provided by NatureServe in collaboration with Bruce Patterson, Wes Sechrest, Marcelo Tognelli, Gerardo Ceballos, The Nature Conservancy-Migratory Bird Program, Conservation International-CABS, World Wildlife Fund-US, and Environment Canada-WILDSPACE."

Citation for Amphibian Range Maps of the Western Hemisphere:
IUCN, Conservation International, and NatureServe. 2004. Global Amphibian Assessment. IUCN, Conservation International, and NatureServe, Washington, DC and Arlington, Virginia, USA.

Acknowledgement Statement for Amphibian Range Maps of the Western Hemisphere:
"Data developed as part of the Global Amphibian Assessment and provided by IUCN-World Conservation Union, Conservation International and NatureServe."

NOTE: Full metadata for the Bird Range Maps of North America is available at:
http://www.natureserve.org/library/birdDistributionmapsmetadatav1.pdf.

Full metadata for the Mammal Range Maps of North America is available at:
http://www.natureserve.org/library/mammalsDistributionmetadatav1.pdf.

Restrictions on Use: Permission to use, copy and distribute documents delivered from this server is hereby granted under the following conditions:
  1. The above copyright notice must appear in all copies;
  2. Any use of the documents available from this server must be for informational purposes only and in no instance for commercial purposes;
  3. Some data may be downloaded to files and altered in format for analytical purposes, however the data should still be referenced using the citation above;
  4. No graphics available from this server can be used, copied or distributed separate from the accompanying text. Any rights not expressly granted herein are reserved by NatureServe. Nothing contained herein shall be construed as conferring by implication, estoppel, or otherwise any license or right under any trademark of NatureServe. No trademark owned by NatureServe may be used in advertising or promotion pertaining to the distribution of documents delivered from this server without specific advance permission from NatureServe. Except as expressly provided above, nothing contained herein shall be construed as conferring any license or right under any NatureServe copyright.
Information Warranty Disclaimer: All documents and related graphics provided by this server and any other documents which are referenced by or linked to this server are provided "as is" without warranty as to the currentness, completeness, or accuracy of any specific data. NatureServe hereby disclaims all warranties and conditions with regard to any documents provided by this server or any other documents which are referenced by or linked to this server, including but not limited to all implied warranties and conditions of merchantibility, fitness for a particular purpose, and non-infringement. NatureServe makes no representations about the suitability of the information delivered from this server or any other documents that are referenced to or linked to this server. In no event shall NatureServe be liable for any special, indirect, incidental, consequential damages, or for damages of any kind arising out of or in connection with the use or performance of information contained in any documents provided by this server or in any other documents which are referenced by or linked to this server, under any theory of liability used. NatureServe may update or make changes to the documents provided by this server at any time without notice; however, NatureServe makes no commitment to update the information contained herein. Since the data in the central databases are continually being updated, it is advisable to refresh data retrieved at least once a year after its receipt. The data provided is for planning, assessment, and informational purposes. Site specific projects or activities should be reviewed for potential environmental impacts with appropriate regulatory agencies. If ground-disturbing activities are proposed on a site, the appropriate state natural heritage program(s) or conservation data center can be contacted for a site-specific review of the project area (see Visit Local Programs).

Feedback Request: NatureServe encourages users to let us know of any errors or significant omissions that you find in the data through (see Contact Us). Your comments will be very valuable in improving the overall quality of our databases for the benefit of all users.