Villosa iris - (I. Lea, 1829)
Rainbow Mussel
Other English Common Names: Rainbow
Taxonomic Status: Accepted
Related ITIS Name(s): Villosa iris (I. Lea, 1829) (TSN 80202)
French Common Names: villeuse irisée
Unique Identifier: ELEMENT_GLOBAL.2.117705
Element Code: IMBIV47060
Informal Taxonomy: Animals, Invertebrates - Mollusks - Freshwater Mussels
 
Kingdom Phylum Class Order Family Genus
Animalia Mollusca Bivalvia Unionoida Unionidae Villosa
Genus Size: C - Small genus (6-20 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: Villosa iris
Taxonomic Comments: This database follows Williams et al. (2017). Watters (2018), based on Kuehnl (2009), recognize Cambarunio dactylus as a species distinct from Villosa iris.

Part of a complex formed by differing shell shapes and apparently different behaviors. Revision of this species group requires analysis of shell, anatomical, and biochemical characters and must encompass all species of the genus Villosa. Due to much confusion surrounding the use of Unio nebulosus within the Villosa iris complex, Parmalee and Bogan (1998) chose to list all the described taxa from the Ohio, Tennessee, and Cumberland River systems as synonyms of Villosa iris and restrict the use of Villosa nebulosa to the species occurring in the headwaters of the Mobile Bay Basin.
Conservation Status
Help

NatureServe Status

Global Status: G5
Global Status Last Reviewed: 21May2009
Global Status Last Changed: 25Nov1996
Rounded Global Status: G5 - Secure
Reasons: This species is found throughout the Tennessee, Cumberland, and Ohio River basins, the upper Mississippi River, and the St. Lawrence River system from Lake Huron to Lake Ontario including their tributaries and is considered stable in much of its range but is declining significantly in Canada.
Nation: United States
National Status: N5 (11May2006)
Nation: Canada
National Status: N1 (03Aug2017)

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 Alabama (S3), Arkansas (S2S3), Illinois (S1), Indiana (S3), Kentucky (SNR), Michigan (S3), Missouri (S4), New York (S2S3), North Carolina (S2), North Dakota (SNR), Ohio (S5), Oklahoma (S1), Pennsylvania (S3), Tennessee (S5), Virginia (S4), West Virginia (S2), Wisconsin (S1)
Canada Ontario (S2S3)

Other Statuses

Canadian Species at Risk Act (SARA) Schedule 1/Annexe 1 Status: E (07Mar2013)
Committee on the Status of Endangered Wildlife in Canada (COSEWIC): Special Concern (26Nov2015)
Comments on COSEWIC: Reason for designation: This attractive yellowish green to brown mussel with green rays is widely distributed in southern Ontario but has been lost from Lake Erie and the Detroit and Niagara rivers and much of Lake St. Clair due to zebra mussel infestations. It still occurs in small numbers in several watersheds but the area of occupancy and the quality and extent of habitat are declining, with concern that increasing industrial agricultural and intensive livestock activities will impact the largest population in the Maitland River.

Status history: Designated Endangered in April 2006. Status re-examined and designated Special Concern in November 2015.

American Fisheries Society Status: Currently Stable (01Jan1993)

NatureServe Global Conservation Status Factors

Range Extent: 200,000-2,500,000 square km (about 80,000-1,000,000 square miles)
Range Extent Comments: This species is found throughout the Tennessee, Cumberland, and Ohio River basins, the upper Mississippi River, and the St. Lawrence River system from Lake Huron to Lake Ontario including their tributaries (Parmalee and Bogan, 1998). Due to much confusion surrounding the use of Unio nebulosus within the Villosa iris complex, Parmalee and Bogan (1998) chose to list all the described taxa from the Ohio, Tennessee, and Cumberland River systems as synonyms of Villosa iris and restrict the use of Villosa nebulosa to the species occurring in the headwaters of the Mobile Bay Basin. In Canada, it was historically known from the Ausable, Bayfield, Detroit, Grant, Maitland, Moira, Niagara, Salmon, Saugeen, Sydenham, Thames and Trent Rivers, as well as Lakes Huron, Ontario, Erie, and St. Clair; but it appears to have been lost from the lower Great Lakes and connecting channels, except for the Lake St. Clair Delta, but it is still extant in most rivers (COSEWIC, 2006). Recently this species has been confirmed to be likely extirpated from the main channel of the Detroit River between Lake St. Clair and Lake Erie, Michigan/Ontario; due to zebra mussel invasion (Schloesser et al., 2006).

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

Number of Occurrences: > 300
Number of Occurrences Comments: In Wisconsin, this species is extremely rare (Mathiak, 1979). In Illinois, it is restricted to the north fork Vermilion River where it is sporadic (Cummings and Mayer, 1997). It was recently collected in the Middle Fork North Branch Vermillion River and Jordan Creek in Illinois and Indiana (Szafoni et al., 2000); recently in the Fox River basin (weathered subfossil) and in Wisconsin (live) in the Mukwonago River (possibly the only remaining population in the entire Upper Mississippi River basin) (Schanzle et al., 2004). Indiana distribution: Wabash mainstem (historical) and tributaries (current) (Fisher, 2006), Tippecanoe (Cummings and Berlocher, 1990), East Fork White (Harmon, 1992). In Ohio, it is widespread across the state but absent from the unglaciated southeast (Watters, 1992; 1995; Lyons et al., 2007; Grabarciewicz, 2008; Watters et al., 2009). In North Carolina, it is reported from the Hiwassee, Little Tennessee, and historically from the French Broad Rivers (Bogan, 2002) in Cherokee, Clay, Jackson, Macon, and Swain Cos. (LeGrand et al., 2006). It was reported from the upper South Fork Holston (Stansbery and Clench, 1978) and recently in Copper Creek and Upper Clinch river in Virginia (Fraley and Ahlstedt, 2000; Jones et al., 2001; Hanlon et al., 2009). Jones and Neves (2007) summarize distribution in the upper North Fork Holston River (Smyth and Bland Cos., Virginia) as rkm 135.8 to 209.2. In Tennessee, it occurs throughout the upper Tennessee River drainage including the Powell, Clinch, Holston, Watauga, French Broad, Nolichucky, Little Pigeon, Little, Obed, Little Tennessee, Hiwassee, and Sequatchie Rivers. In the lower Tennessee River, it may be found in numerous tributaries including the Elk, Buffalo, and Duck Rivers. In the Cumberland River system, it is found sporadically in the Big South Fork Cumberland, Obey, Caney Fork, Collins, and Stones Rivers, but rarely in the mainstem of the Cumberland River (Parmalee and Bogan, 1998). In Alabama, it is restricted to the Tennessee River system (Mirarchi, 2004) in the Paint Rock River (Ahlstedt, 1996) and other tributaries (Williams et al., 2008). In Kentucky, it is occasional to sporadic in the lower Cumberland River and eastward (Cicerello and Schuster, 2003), South Fork Kentucky (Evans, 2008) and Green (Gordon, 1991). It was recently collected from 6 of 38 sites surveyed (only found alive at a single site) in the Tonawanda Creek basin (Niagara River drainage) in western New York (Marangelo and Strayer, 2000). It was found in Little Mahoning Creek watershed, Pennsylvania (Chapman and Smith, 2008). This species is also known from the Clinton River drainage in Michigan (Trdan and Hoeh, 1993; Strayer, 1980) and southern upper peninsula (Goodrich and Van der Schalie, 1939) in Lakes Michigan and St. Clair basins (Badra and Goforth, 2003). Specimens from the Black River (St. Clair drainage), Michigan, were relocated to the Detroit River in 1992 (Trdan and Hoeh, 1993). It was recently found in the Little River, Oklahoma (Vaughn and Taylor, 1999; Vaughn, 2000); where it was known historically (Branson, 1984). It was collected in the 1990s in the Poteau (Vaughn and Spooner, 2004) and Mountain Fork (Spooner and Vaughn, 2007) Rivers, Arkansas/Oklahoma. In Canada, this species was once widely distributed and relatively common in southern Ontario, but is now extremely rare in most systems, but significant populations can still be found in the Sydenham (Metcalfe-Smith et al., 2003), Maitland River (Lake Huron drainage), Moira River (Lake Ontario drainage), and the delta area of Lake St. Clair (Metcalfe-Smith and Cudmore-Vokey, 2004).

Population Size: >1,000,000 individuals
Population Size Comments: A small population, estimated at 7200 individuals, occupies the Canadian waters of the Lake St. Clair delta but is declining at a rate of 7% per year. Other Canadian populations (Ausable, Grand, Saugeen, sydenham Rivers) are very small with only 20 specimens collected from 148 sites in these rivers over the past 10 years. The population in the East Sydenham River consists of 18,900 individuals, but appears to be declining. The Upper Thames River population is estimated at 40,000 mussels, but may also be declining. The Maitland River supports the largest and healthiest Canadian populatin with CPUE 10 to 100 times higher than any other Canadian water body (COSEWIC, 2006).

Number of Occurrences with Good Viability/Integrity: Very many (>125)
Viability/Integrity Comments: Jones and Neves (2007) summarize distribution in the upper North Fork Holston River (Smyth and Bland Cos., Virginia) as rkm 135.8 to 209.2 where it is the second most abundant species.

Overall Threat Impact: Medium
Overall Threat Impact Comments: The greatest threats occur in the Great Lakes portion of the range. This species has been lost from the lower Great Lakes and connecting channels largely due to impacts of the zebra mussel. Heavy loadings of sediment, nutrients and toxic substances from urban and agricultural sources have degratded mussel habitat throughout southern Ontario. The species is particularly sensitive to copper and ammonia (COSEWIC, 2006).

Short-term Trend: Decline of <30% to relatively stable
Short-term Trend Comments: In Canada, this species was once widely distributed and relatively common in southern Ontario, but is now extremely rare in most systems, but significant populations can still be found in the Maitland River (Lake Huron drainage), Moira River (Lake Ontario drainage), and the delta area of Lake St. Clair (this population threatened by zebra mussels) (Metcalfe-Smith and Cudmore-Vokey, 2004). In Canada, it was historically known from the Ausable, Bayfield, Detroit, Grant, Maitland, Moira, Niagara, Salmon, Saugeen, Sydenham, Thames and Trent Rivers, as well as Lakes Huron, Ontario, Erie, and St. Clair; but it appears to have been lost from the lower Great Lakes and connecting channels, except for the Lake St. Clair Delta, but it is still extant in most rivers although it is likely extirpated from the Niagara and Detroit Rivers and most previously inhabited areas of Lake Erie and Lake St. Clair (COSEWIC, 2006). It was recently documented in the Fox River basin in Illinois by only weathered subfossil material and in Wisconsin by live specimens in the Mukwonago River (possibly the only remaining population in the entire Upper Mississippi River basin) (Schanzle et al., 2004).

Long-term Trend: Decline of <30% to increase of 25%
Long-term Trend Comments: In Canada, it was historically known from the Ausable, Bayfield, Detroit, Grant, Maitland, Moira, Niagara, Salmon, Saugeen, Sydenham, Thames and Trent Rivers, as well as Lakes Huron, Ontario, Erie, and St. Clair; but it appears to have been lost from the lower Great Lakes and connecting channels, except for the Lake St. Clair Delta, but it is still extant in most rivers (COSEWIC, 2006).

Intrinsic Vulnerability: Unknown

Environmental Specificity: Narrow. Specialist or community with key requirements common.
Environmental Specificity Comments: This species lives in riffles along the edges of emerging vegetation, such as Justicia beds, in gravel and sand in moderate to strong current. It becomes most numerous in clean, well-oxygenated stretches at depths of less than three feet (Parmalee and Bogan, 1998).

Other NatureServe Conservation Status Information

Distribution
Help
Global Range: (200,000-2,500,000 square km (about 80,000-1,000,000 square miles)) This species is found throughout the Tennessee, Cumberland, and Ohio River basins, the upper Mississippi River, and the St. Lawrence River system from Lake Huron to Lake Ontario including their tributaries (Parmalee and Bogan, 1998). Due to much confusion surrounding the use of Unio nebulosus within the Villosa iris complex, Parmalee and Bogan (1998) chose to list all the described taxa from the Ohio, Tennessee, and Cumberland River systems as synonyms of Villosa iris and restrict the use of Villosa nebulosa to the species occurring in the headwaters of the Mobile Bay Basin. In Canada, it was historically known from the Ausable, Bayfield, Detroit, Grant, Maitland, Moira, Niagara, Salmon, Saugeen, Sydenham, Thames and Trent Rivers, as well as Lakes Huron, Ontario, Erie, and St. Clair; but it appears to have been lost from the lower Great Lakes and connecting channels, except for the Lake St. Clair Delta, but it is still extant in most rivers (COSEWIC, 2006). Recently this species has been confirmed to be likely extirpated from the main channel of the Detroit River between Lake St. Clair and Lake Erie, Michigan/Ontario; due to zebra mussel invasion (Schloesser et al., 2006).

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 AL, AR, IL, IN, KY, MI, MO, NC, ND, NY, OH, OK, PA, TN, VA, WI, WV
Canada ON

Range Map
No map available.


U.S. Distribution by County Help
State County Name (FIPS Code)
AL Jackson (01071), Madison (01089), Marshall (01095)
AR Benton (05007), Carroll (05015), Cleburne (05023), Fulton (05049), Izard (05065), Lawrence (05075), Madison (05087), Marion (05089), Montgomery (05097), Newton (05101), Pope (05115), Randolph (05121), Searcy (05129), Sharp (05135), Stone (05137), Van Buren (05141), Washington (05143), Woodruff (05147)*
IL Mchenry (17111), Vermilion (17183)
MI Allegan (26005)*, Alpena (26007)*, Arenac (26011)*, Barry (26015), Berrien (26021)*, Branch (26023), Calhoun (26025), Cass (26027), Clinton (26037), Eaton (26045), Genesee (26049), Gladwin (26051)*, Gratiot (26057), Hillsdale (26059), Huron (26063)*, Ingham (26065), Ionia (26067), Iosco (26069)*, Isabella (26073), Jackson (26075), Kalamazoo (26077)*, Kent (26081), Lapeer (26087)*, Lenawee (26091), Livingston (26093), Macomb (26099), Mecosta (26107), Menominee (26109)*, Midland (26111), Missaukee (26113), Monroe (26115), Montcalm (26117), Muskegon (26121)*, Oakland (26125), Ogemaw (26129)*, Ottawa (26139)*, Roscommon (26143), Saginaw (26145), Sanilac (26151), Shiawassee (26155), St. Clair (26147), St. Joseph (26149), Tuscola (26157), Van Buren (26159), Washtenaw (26161), Wayne (26163)
NC Cherokee (37039), Clay (37043), Jackson (37099), Macon (37113), Swain (37173)
NY Cayuga (36011), Chautauqua (36013), Erie (36029), Genesee (36037), Livingston (36051), Monroe (36055), Niagara (36063), Onondaga (36067), Ontario (36069), Orleans (36073), Oswego (36075), Wayne (36117)
OK Le Flore (40079), McCurtain (40089), Pushmataha (40127)
PA Allegheny (42003), Armstrong (42005), Beaver (42007), Butler (42019), Clarion (42031), Crawford (42039), Cumberland (42041), Dauphin (42043), Erie (42049), Fayette (42051)*, Greene (42059)*, Huntingdon (42061), Indiana (42063), Juniata (42067), Lawrence (42073), Mercer (42085), Mifflin (42087), Perry (42099), Venango (42121)
TN Blount (47009), Cumberland (47035), Marion (47115), Morgan (47129)
WI Fond Du Lac (55039), Kenosha (55059)*, Ozaukee (55089)*, Rock (55105)*, Sheboygan (55117), Walworth (55127)*, Washington (55131), Waukesha (55133)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
02 Lower Susquehanna-Penns (02050301)+*, Lower Juniata (02050304)+, Lower Susquehanna-Swatara (02050305)+
04 Manitowoc-Sheboygan (04030101)+, Cedar-Ford (04030109)+*, Little Calumet-Galien (04040001)+*, Milwaukee (04040003)+, St. Joseph (04050001)+, Black-Macatawa (04050002)+*, Kalamazoo (04050003)+, Upper Grand (04050004)+, Maple (04050005)+, Lower Grand (04050006)+, Thornapple (04050007)+, Muskegon (04060102)+, Thunder Bay (04070006)+*, Au Sable (04070007)+*, Au Gres-Rifle (04080101)+*, Kawkawlin-Pine (04080102)+*, Pigeon-Wiscoggin (04080103)+*, Tittabawassee (04080201)+, Pine (04080202)+, Shiawassee (04080203)+, Flint (04080204)+*, Cass (04080205)+, St. Clair (04090001)+, Lake St. Clair (04090002)+, Clinton (04090003)+, Detroit (04090004)+, Huron (04090005)+, Ottawa-Stony (04100001)+*, Raisin (04100002)+, St. Joseph (04100003)+, Tiffin (04100006)+, Chautauqua-Conneaut (04120101)+, Niagara (04120104)+, Lake Erie (04120200)+*, Oak Orchard-Twelvemile (04130001)+, Lower Genesee (04130003)+, Irondequoit-Ninemile (04140101)+, Seneca (04140201)+
05 Conewango (05010002)+, Middle Allegheny-Tionesta (05010003)+, French (05010004)+, Middle Allegheny-Redbank (05010006)+, Lower Allegheny (05010009)+, Cheat (05020004)+*, Lower Monongahela (05020005)+*, Upper Ohio (05030101)+, Shenango (05030102)+, Mahoning (05030103)+*, Beaver (05030104)+*, Connoquenessing (05030105)+, Vermilion (05120109)+
06 Watts Bar Lake (06010201)+, Upper Little Tennessee (06010202)+, Tuckasegee (06010203)+, Emory (06010208)+, Hiwassee (06020002)+, Sequatchie (06020004)+, Wheeler Lake (06030002)+
07 Upper Rock (07090001)+, Crawfish (07090002)+*, Upper Fox (07120006)+
08 Ouachita Headwaters (08040101)+
11 Beaver Reservoir (11010001)+, Buffalo (11010005)+, Lower Black (11010009)+, Spring (11010010)+, Eleven Point (11010011)+, Strawberry (11010012)+, Upper White-Village (11010013)+*, Little Red (11010014)+, Illinois (11110103)+, Dardanelle Reservoir (11110202)+, Kiamichi (11140105)+, Upper Little (11140107)+, Mountain Fork (11140108)+, Lower Little (11140109)+*
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
U.S. Distribution by Watershed (based on multiple information sources) Help
Ecology & Life History
Help
Reproduction Comments: Glochidial hosts include Betta splendens (Siamese fighting fish), Erimystax dissimilis (streamline chub), Etheostoma blennioides (greenside darter), Etheostoma caeruleum (rainbow darter), Etheostoma camurum (bluebreast darter), Lepomis cyanellus (green sunfish), Luxilus chrysocephalus (striped shiner), Micropterus dolomieu (smallmouth bass), Micropterus salmoides (largemouth bass), and Perca flavescens (yellow perch) (Watters and O'Dee, 1997). New host fish confirmation from Watters et al. (2005): Cottus bairdi (mottled sculpin) and Micropterus dolomieu (smallmouth bass). One host, Micropterus salmoides (largemouth bass), is capable of acquired resistance to glochidial infection following repeated infection attempts in the laboratory (Dodd et al., 2005).
Habitat Type: Freshwater
Non-Migrant: N
Locally Migrant: N
Long Distance Migrant: N
Riverine Habitat(s): BIG RIVER, CREEK, High gradient, MEDIUM RIVER, Moderate gradient, Riffle
Lacustrine Habitat(s): Shallow water
Special Habitat Factors: Benthic
Habitat Comments: This species lives in riffles along the edges of emerging vegetation, such as Justicia beds, in gravel and sand in moderate to strong current. It becomes most numerous in clean, well-oxygenated stretches at depths of less than three feet (Parmalee and Bogan, 1998). It is most abundant in small to medium-sized rivers but can also be found in inland lakes (COSEWIC, 2006).
Economic Attributes Not yet assessed
Help
Management Summary
Help
Stewardship Overview: This species was deisignated as endangered in Canada in April 2006 and a status report prepared (COSEWIC, 2006).
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: 21May2009
NatureServe Conservation Status Factors Author: Cordeiro, J.
Management Information Edition Date: 17Jan2008
Management Information Edition Author: Cordeiro, J.
Element Ecology & Life History Edition Date: 17Jan2008
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
  • Baker, F.C. 1906. A catalogue of the mollusca of Illinois. Bull. Ill. State Lab. Nat. Hist. 7:53-136.

  • Branson, B.A. 1984. The mussels (Unionacea: Bivalvia) of Oklahoma- Part 3: Lampsilini. Proceedings of the Oklahoma Academy of Science, 64: 20-36.

  • Burch, J.B. 1975. Freshwater unionacean clams (mollusca: pelecypoda) of North America. Malcological Publications. Hamburg, Michigan. 204 pp.

  • COSSARO. 2016. Ontario Species at Risk Evaluation Report for Rainbow (Villosa iris). June 2016 (final). 13pp.

  • Clarke, A.H. and C.O. Berg. 1959. The freshwater mussels of central New York. Cornell University Agricultural Experiment Station Memoir 367.

  • Cummings, K.S. and J.M. Berlocher. 1990. The naiades or freshwater mussels (Bivalvia: Unionidae) of the Tippecanoe River, Indiana. Malacological Review 23:83-98.

  • Cummings, Kevin S. et al. 1992. Survey of the Freshwater Mussels (Mollusca: Unionidae) of the Wabash River Drainage. Final Report. INHS Center for Biodiversity Tech. Rep. 1992 (1):210 pp.

  • Dextrase, A.J. 2005. COSSARO Candidate Species at Risk Evaluation Form for Rainbow (Villosa iris). Species At Risk Unit, Biodiversity Section, Fish and Wildlife Branch. Prepared for Committee on the Status of Species at Risk in Ontario (COSSARO), Ontario Ministry of Natural Resources, Peterborough. 3 October, 8 pp.

  • Dodd, B.J., M.C. Barnhart, C.L. Rogers-Lowery, T.B. Fobian, and R.V. Dimock. 2005. Cross-resistance of largemouth bass to glochidia of unionid mussels. Journal of Parasitology, 91(5): 1064-1072.

  • Ecological Specialists, Inc. 1996. Unionid Mussel Survey of the Blue River, Indiana. Prepared for The Nature Conservancy. 23 pp.

  • Evans, R. 2008. Year 1 update of freshwater mollusk monitoring in the South Fork Kentucky River system. Ellipsaria, 10(3): 12-13.

  • Fisher, B.E. 2006. Current status of freshwater mussels (Order Unionoida) in the Wabash River drainage of Indiana. Proceedings of the Indiana Academy of Science, 115(2): 103-109.

  • Fraley, S.J. and S.A. Ahlstedt. 2000. The recent decline of the native mussels (Unionidae) of Copper Creek, Russell and Scott Counties, Virginia. Pages 189-195 in R.A. Tankersley, D.I. Warmolts, G.T. Watters, B.J. Armitage, P.D. Johnson, and R.S. Butler (eds.). Freshwater Mollusk Symposia Proceedings. Ohio Biological Survey, Columbus, Ohio. 274 pp.

  • Goodrich, C. and H. van der Schalie. 1939. Aquatic mollusks of the upper peninsula of Michigan. Miscellaneous Publications of the Museum of Zoology, University of Michigan, 43: 1-45.

  • Harmon, J.L. 1992. Naiades (Bivalvia: Unionidae) of Sugar Creek, east fork White River drainage, in central Indiana. Malacology Data Net 3(1-4):31-42.

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

  • Jones, J.W. and R.J. Neves. 2007. Freshwater mussel status: Upper North Fork Holston River, Virginia. Northeastern Naturalist, 14(3): 471-480.

  • Jones, J.W., R.J. Neves, M.A. Patterson, C.R. Good, and A. DiVittorio. 2001. A status survey of freshwater mussel populations in the upper Clinch River, Tazewell County, Virginia. Banisteria, 17: 20-30.

  • Kuehnl, K.F. 2009. Exploring levels of genetic variation in the freshwater mussel genus Villosa (Bivalvia: Unionidae) at different spatial and systematic scales: Implications for biogeography, taxonomy, and conservation. Ph.D. dissertation, The Ohio State University, Columbus.

  • LeGrand, H.E., Jr., S.P. Hall, S.E. McRae, and J.T. Finnegan. 2006. Natural Heritage Program List of the Rare Animal Species of North Carolina. North Carolina Natural Heritage Program, Raleigh, North Carolina. 104 pp.

  • 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.

  • Lyons, M.S., R.A. Krebs, J.P. Holt, L.J. Rundo, and W. Zawiski. 2007. Assessing causes of change in the freshwater mussels (Bivalvia: Unionidae) in the Black River, Ohio. American Midland Naturalist, 158: 1-15.

  • Marangelo, P.J. and D.L. Strayer. 2000. The freshwater mussels of the Tonawanda Creek basin in western New York. Walkerana, 11(25): 97-106.

  • Mathiak, H.A. 1979. A river survey of the unionid mussels of Wisconsin, 1973-1977. Sand Shell Press: Horicon, Wisconsin. 75 pp.

  • Mirarchi, R.E., et al. 2004a. Alabama Wildlife. Volume One: A Checklist of Vertebrates and Selected Invertebrates: Aquatic Mollusks, Fishes, Amphibians, Reptiles, Birds, and Mammals. University of Alabama Press: Tuscaloosa, Alabama. 209 pp.

  • 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.

  • Parmalee, P.W. 1967. The fresh-water mussels of Illinois. Ill. State Mus., Popular Sci. Series Vol. VIII. 108pp.

  • Parmalee, P.W. and A.E. Bogan. 1998. The freshwater mussels of Tennessee. University of Tennessee Press, Knoxville, Tennesee. 328 pp.

  • Schanzle, R.W., G.W. Kruse, J.A. Kath, R.A. Klocek, and K.S. Cummings. 2004. The freshwater mussels (Bivalvia: Unionidae) of the Fox River basin, Illinois and Wisconsin. Illinois Natural History Biological Notes, 141: 1-35.

  • Schloesser, D.W., J.L. Metcalfe-Smith, W.P. Kovalak, G.D. Longton, and R.D. Smithee. 2006. Extirpation of freshwater mussels (Bivalvia: Unionidae) following the invasion of dreissenid mussels in an interconnecting river of the Laurentian Great Lakes. American Midland Naturalist, 155: 307-320.

  • Smith, J. 1999. Unionid Ranks. Email letter to D.A. Sutherland, dated September 27. 1 pp.

  • Spoo, A. 2008. The Pearly Mussels of Pennsylvania. Coachwhip Publications: Landisville, Pennsylvania. 210 pp.

  • Stansbery, D. H. and W. J. Clench. 1977 [1978]. The Pleuroceridae and Unionidae of the Upper South Fork Holston River in Virginia. Bulletin of the American Malacological Union 1977:75-79.

  • Strayer, D. 1980. The freshwater mussels (Bivalvia: Unionidae) of the Clinton River, Michigan, with comments on man's impact on the fauna, 1870-1978. The Nautilus 94(4):142-149.

  • 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.

  • Strayer, David L. and K.J. Jirka. 1997. The Pearly Mussels (Bivalva: Unionoidea) of New York State. New York State Museum Memoir 26. The New York State Education Department.

  • Strayer, David L., Kurt J. Jirka, and Kathryn J. Schneider. 1991. Recent collections of freshwater mussels (Bivalvia: Unionidae) from western New York. Walkerana 5(12): 63-72.

  • Szafoni, R.E., K.S. Cummings, and C.A. Mayer. 2000. Freshwater mussels (Mollusca: Unionidae) of the Middle Branch, North Fork Vermillion River, Illinois, Indiana. Transactions of the Illinois State Academy of Sceince, 93(3): 229-237.

  • Trdan, R.J. and W.R. Hoeh. 1993. Relocation of two state-listed freshwater mussel species (Epioblasma torulosa rangiana and Epioblasma triquetra) in Michigan. Pages 100-105 in K.S. Cummings, A.C. Buchanan, and L.M. Koch. (eds.). Conservation and Management of Freshwater Mussels. Proceedings of a UMRCC Symposium, 12-14 October 1992, St. Louis, Missouri. Upper Mississippi River Conservation Committee, Rock Island, Illinois. 189 pp.

  • 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.

  • Valenti, T.W., D.S. Cherry, R.J. Neves, and J. Schmerfeld. 2005. Acute and chronic toxicity of mercury to early life stages of the rainbow mussel, Villosa iris (Bivalvia: Unionidae). Environmental Toxicology and Chemistry, 24(5): 1242-1246.

  • 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.

  • Vaughn, C.C. 2000. Changes in the mussel fauna of the middle Red River drainage: 1910 - present. Pages 225-232 in R.A. Tankersley, D.I. Warmolts, G.T. Watters, B.J. Armitage, P.D. Johnson, and R.S. Butler (eds.). Freshwater Mollusk Symposia Proceedings. Ohio Biological Survey, Columbus, Ohio. 274 pp.

  • Vaughn, C.C., and C.M. Taylor. 1999. Impoundments and the decline of freshwater mussels: a case study of an extinction gradient. Conservation Biology 13(4):912-920.

  • Watters, G. T. 2018. A preliminary review of the nominal genus Villosa of freshwater mussels (Bivalvia, Unionidae) in North America. Visaya, Supplement (10). 140 pp.

  • Watters, G. Thomas. 1994. An Annotated Bibliography of the Reproduction and Propogation of the Unionoidea (Primarily of North America). Ohio Biological Survey, College of Biological Sciences, The Ohio State University. In cooperation with Ohio Division of Wildlife. 158 pp.

  • Watters, G. Thomas. 1996. 1996 Survey of the Mussels of the Fish Creek Drainage. Final Report to the Indiana Chapter of The Nature Conservancy.

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

  • Watters, G.T. 1992b. Distribution of the Unionidae in south central Ohio. Malacology Data Net 3(1-4):56-90.

  • Watters, G.T. and S.H. O'Dee. 1997. Potential hosts for Villosa iris (Lea, 1829). Triannual Unionid Report, 12: 7.

  • Watters, G.T., T. Menker, S. Thomas, and K. Luehnl. 2005. Host identifications or confirmations. Ellipsaria, 7(2): 11-12.

  • Wendeln, K.L., J.R. Runkle, and G.T. Watters. 2009. The freshwater mussels (Unionidae) of Twin Creek, Southwest Ohio. Journal of Freshwater Ecology 24(3):451-460. DOI: 10.1080/02705060.2009.9664318

  • 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., A. E. Bogan, and J. T Garner. 2008. Freshwater mussels of Alabama & the Mobile Basin in Georgia, Mississippi, & Tennessee. University of Alabama Press, Tuscaloosa, Alabama. 908 pages.

  • 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.

References for Watershed Distribution Map
  • Ahlstedt, S.A. 1995-1996. Status survey for federally listed endangered freshwater mussel species in the Paint Rock River system, northeastern Alabama, U.S.A. Walkerana 8(19):63-80.

  • Badra, P.J. and R.R. Goforth. 2003. Freshwater mussel surveys of Great Lakes tributary rivers in Michigan. Report Number MNFI 2003-15 to the Michigan Department of Environmental Quality, Coastal Zone Management Unit, Lansing, Michigan. 40 pp.

  • Bogan, A.E. 2002. Workbook and key to the freshwater bivalves of North Carolina. North Carolina Museum of Natural Sciences: Raleigh, North Carolina. 101 pp.

  • COSEWIC. 2006. COSEWIC assessment and status report on the rainbow mussel Villosa iris in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa, Canada. 38 pp.

  • Chapman, E.J. and T.A. Smith. 2008. Structural community changes in freshwater mussel populations of Little Mahoning Creek, Pennsylvania. American Malacological Bulletin, 26: 161-169.

  • Cicerello, R.R. and G.A. Schuster. 2003. A guide to the freshwater mussels of Kentucky. Kentucky State Nature Preserves Commission Scientific and Technical Series 7:1-62.

  • Cummings, K.S. and C.A. Mayer. 1997. Distributional checklist and status of Illinois freshwater mussels (Mollusca: Unionacea). Pages 129-145 in: K.S. Cummings, A.C. Buchanan, C.A. Mayer, and T.J. Naimo (eds.) Conservation and management of freshwater mussels II: initiatives for the future. Proceedings of a UMRCC Symposium, October 1995, St. Louis, Missouri. Upper Mississippi River Conservation Committee, Rock Island, Illinois.

  • Galbraith, H.S., D.E. Spooner, and C.C. Vaughn. 2008. Status of rare and endangered freshwater mussels in southeastern Oklahoma. The Southwestern Naturalist, 53(1): 45-50.

  • Gordon, M.E. 1991. Aquatic mollusca of the Rough River in the vicinity of the Fort Hartford Mine site, Ohio County, Kentucky. Unpublished final report for Environmental and Safety Designs, Memphis, Tennessee, 6 July 1991. 10 pp.

  • Grabarkiewicz, J.D. 2008. Three years of unionid surveys in Swan Creek, Lower Maumee River watershed, Lucas Co., OH. Final Report to the Ohio Division of Wildlife, Toledo Naturalists' Association, and Metroparks of the Toledo Area, Toledo, Ohio. 18 pp. + app.

  • Hanlon, S.D., M.A. Petty, and R.J. Neves. 2009. Status of native freshwater mussels in Copper Creek, Virginia. Southeastern Naturalist 8(1):1-18.

  • Harmon, J.L. 1989. Freshwater bivalve mollusks (Bivalvia: Unionidae) of Graham Creek, a small southeastern Indiana stream. Malacology Data Net, 2(5/6): 113-121.

  • 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.

  • Metcalfe-Smith, J.L., J. Di Maio, S.K. Staton, and S.R. De Solla. 2003. Status of the freshwater mussel communities of the Sydenham River, Ontario, Canada. American Midland Naturalist 150:37-50.

  • Morris, T.J. and J. Di Maio. 1999. Current distributions of freshwater mussels (Bivalvia: Unionidae) in rivers of southwestern Ontario. Malacological Review, 31/32(1): 9-17.

  • Oesch, R.D. 1995. Missouri Naiades. A Guide to the Mussels of Missouri. Second edition. Missouri Department of Conservation: Jefferson City, Missouri. viii + 271 pp.

  • Parmalee, P.W. and A.E. Bogan. 1998. The Freshwater Mussels of Tennessee. University of Tennessee Press: Knoxville, Tennessee. 328 pp.

  • Spooner, D.E. and C.C. Vaughn. 2007. Mussels of the Mountain Fork River, Arkansas and Oklahoma. Publications of the Oklahoma Biological Survey, 2nd series, 8: 14-18.

  • Strayer, D.L. and K.J. Jirka. 1997. The Pearly Mussels of New York State. New York State Museum Memoir 26. The University of the State of New York. 113 pp. + figures.

  • Vaughn, C.C. and D.E. Spooner. 2004. Status of the mussel fauna of the Poteau River and implications for commercial harvest. American Midland Naturalist, 152: 336-346.

  • Watters, G.T. 1995a. A field guide to the freshwater mussels of Ohio. revised 3rd edition. Ohio Department of Natural Resources, Division of Wildlife, Columbus, Ohio. 122 pp.

  • Watters, G.T., M.A. Hoggarth, and D.H. Stansbery. 2009b. The Freshwater Mussels of Ohio. Ohio State University Press: Columbus, Ohio. 421 pp.

  • Williams, J.D., A.E. Bogan, and J.T. Garner. 2008. Freshwater Mussels of Alabama & the Mobile Basin in Georgia, Mississippi & Tennessee. University of Alabama Press: Tuscaloosa, Alabama. 908 pp.

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.