Planorbella trivolvis - (Say, 1817)
Marsh Rams-horn
Synonym(s): Helisoma trivolvis (Say, 1816)
Taxonomic Status: Accepted
Related ITIS Name(s): Planorbella trivolvis (Say, 1817) (TSN 76671)
French Common Names: hélisome commun de l'Est
Unique Identifier: ELEMENT_GLOBAL.2.118461
Element Code: IMGASN0170
Informal Taxonomy: Animals, Invertebrates - Mollusks - Freshwater Snails
Kingdom Phylum Class Order Family Genus
Animalia Mollusca Gastropoda Basommatophora Planorbidae Planorbella
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Concept Reference
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: Planorbella trivolvis
Taxonomic Comments: Genetic examination of molecular phylogeny of global Planorboidea at the COI and 18S molecular markers indicates all North American taxa within the subfamily Planorbinae form a well-supported clade, as yet unnamed but termed C-Clade (Albrecht et al., 2007).
Conservation Status

NatureServe Status

Global Status: G5
Global Status Last Reviewed: 25Nov2011
Global Status Last Changed: 14Sep1999
Rounded Global Status: G5 - Secure
Reasons: This species is widespread and is considered stable and secure throughout its range. This species has a wide distribution, presumed large population, tolerance of a broad range of habitats, tolerance to habitat modification, lack of substantial immediate threats, and because it is not in decline or is unlikely to be declining fast enough to qualify for listing in a more threatened category.
Nation: United States
National Status: N5 (14Sep1999)
Nation: Canada
National Status: N5 (08Mar2013)

U.S. & Canada State/Province Status
United States Alabama (S5), Alaska (SNR), Arkansas (SNR), California (SNR), Colorado (S5), Connecticut (S4), Florida (S5), Georgia (S5), Idaho (SNR), Illinois (SNR), Indiana (SNR), Iowa (SNR), Kansas (SNR), Kentucky (S5), Louisiana (SNR), Maryland (SNR), Massachusetts (S5), Michigan (SNR), Minnesota (SNR), Mississippi (SNR), Missouri (SNR), Montana (SNR), New York (S5), North Carolina (S5), North Dakota (SNR), Ohio (SNR), Pennsylvania (S5), Rhode Island (SNR), South Carolina (SNR), South Dakota (SNR), Tennessee (S5?), Texas (SNR), Utah (S3S4), Vermont (SNR), Virginia (S4), West Virginia (SNR), Wisconsin (S5), Wyoming (S4)
Canada British Columbia (S5), Manitoba (SNR), New Brunswick (SNR), Newfoundland Island (SNR), Nova Scotia (SNR), Nunavut (SU), Ontario (SNR), Prince Edward Island (SNR), Quebec (SNR), Saskatchewan (SNR), Yukon Territory (SNR)

Other Statuses

IUCN Red List Category: LC - Least concern

NatureServe Global Conservation Status Factors

Range Extent: >2,500,000 square km (greater than 1,000,000 square miles)
Range Extent Comments: Burch (1989) lists distribution of the nominal subspecies as the Atlantic Coast and Mississippi River northward to Arctic Canada and Alaska and southward to Tennessee and Missouri; and for Planorbella trivolvis intertextum as from Long Pine Key in the southern Florida Everglades throughout peninsular Florida and north along the coast to Lake Waccamaw, North Carolina.

Number of Occurrences: > 300
Number of Occurrences Comments: It occurs in ponds, creeks and the Savannah River on property of the Savannah River Power Plant, Aiken, South Carolina (Wood, 1982). In Georgia, this species is distributed across much of the eastern and northern Atlantic Coastal plain (Dillon et al., 2006). In South Carolina (Dillon and Stewart, 2003), it occurs in the Southeastern Plains and Mid-Atlantic Coastal Plains. In North Carolina (Dillon et al., 2006), it occurs across the eastern Atlantic Coastal Plains. In Alabama, it is common but restricted to the Tennessee River system (Mirarchi, 2004). Subspecies intertexta is widely distributed throughout the Florida peninsula and extending northeast along the coastal plain to southeastern North Carolina; while in western Florida it intergrades with Planorbella trivolvis lenta (Thompson, 1999). Pilsbry (1934) lists subspecies intertexta from Long Pine Key, in the southern Everglades, throughout peninsular Florida and north along the coast to Lake Waccamaw, North Carolina. In the Cuyahoga Valley National Park (between Cleveland and Akron, Ohio), this species was recently found in the shallow littoral zone of ponds with a few individuals in pool areas of tributaries in the park (Smith et al., 2002). It is throughout the Salt Fork Big Vermilion River, Illinois (Dexter, 1961). It has been documented in Alaska in the central interior and potentially other areas of the state (Baxter, 1987). Jokinen (2005) found it at Indian Sand Dunes National Lakeshore. In Indiana, Pyron et al. (2008) found it at 16 sites of 123 surveyed (mostly from Wabash drainage northward) and two historical sites (Half Moon Pond and Bass Lake) compared to Goodrich and van der Schalie (1944) who stated it was likely present statewide. It is throughout the Spring River, Missouri and Kansas (Branson, 1966). It is widely distributed throughout Missouri (Adair, Andrew, Audrain, Barry, Barton, Bollinger, Boone, Caldwell, Callaway, Carroll, Cass, Chariton, Clark, Clay, Cole, Cooper, Crawford, Dade, Dallas, Dunklin, Gasconade, Grundy, Harrison, Henry, Hickory, Holt, Howell, Iron, Jackson, Jasper, Jefferson, Johnson, Knox, Lafayette, Lincoln, Linn, Livingston, McDonald, Macon, Mississippi, Montgomery, Newton, Nodaway, Oregon, Ozark, Perry, Pettis, Pike, Platte, Pulaski, Putnam, Ralls, Randolph, Ray, Reynolds, Ripley, St. Charles, St. Louis, Saline, Scott, Shannon, Stoddard, Warren, Washington, and Wayne Cos.) (Wu et al., 1997). Freeman and Perkins (1992) documented it in Nebraska. It occurs in the White River (Gordon, 1982) and Bayou Bartholomew drainages (Minton et al., 2008), Arkansas. In Kentucky it has been documented in the Green (creek in Casey Co., Wolf Lick Creek) and Ohio River (swamp in Union Co.) drainages but is distributed statewide (Branson and Batch, 1983); and Kentuckcy (pond in Madison Co., Silver Creek, Elkhorn Creek, Lake Arlington, farm pond in Madison Co.) and Licking (Slate Creek, Fox Creek) River drainages (Branson and Batch, 1981). Branson and Batch (1987) documented it in Kentucky in the Ohio (Ballard County WMA pond, ), Licking (Townsend Creek in Bourbon Co.), Green (Roundabout Swamp in Butler Co., Crane Pond-Slough in Daviess Co.), Tennessee (East Fork Clarks River in Marshall Co.), Cumberland (Owsley Fork Lake in Jackson Co.), Hatchie-Obion (pond in Fulton Co.) and Kentucky (pond in Madison Co.) drainages. Blair and Sickel (1986) documented it in 1 of 44 sites (Prior Creek, Tennessee) surveyed in Land Between the Lakes (national recreation area between Cumberland River (Lake Berkeley) and Tennessee River (Kentucky Lake)) in Kentucky and Tennessee. In Pennsylvania, it occurs in the Delaware, Ohio, and Susquehanna basins (generally statewide) (Evans and Ray, 2010).

Population Size: >1,000,000 individuals
Population Size Comments: In the Cuyahoga Valley National Park (between Cleveland and Akron, Ohio), this species was recently found in the shallow littoral zone of ponds with a few individuals in pool areas of tributaries in the park (Smith et al., 2002).

Number of Occurrences with Good Viability/Integrity: Unknown

Overall Threat Impact: Low

Environmental Specificity: Broad. Generalist or community with all key requirements common.

Other NatureServe Conservation Status Information

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) Burch (1989) lists distribution of the nominal subspecies as the Atlantic Coast and Mississippi River northward to Arctic Canada and Alaska and southward to Tennessee and Missouri; and for Planorbella trivolvis intertextum as from Long Pine Key in the southern Florida Everglades throughout peninsular Florida and north along the coast to Lake Waccamaw, North Carolina.

U.S. States and Canadian Provinces
Color legend for Distribution Map
Endemism: occurs (regularly, as a native taxon) in multiple nations

U.S. & Canada State/Province Distribution
United States AK, AL, AR, CA, CO, CT, FL, GA, IA, ID, IL, IN, KS, KY, LA, MA, MD, MI, MN, MO, MS, MT, NC, ND, NY, OH, PA, RI, SC, SD, TN, TX, UT, VA, VT, WI, WV, WY
Canada BC, MB, NB, NF, NS, NU, ON, PE, QC, SK, YT

Range Map
No map available.

Ecology & Life History
Habitat Type: Freshwater
Non-Migrant: N
Locally Migrant: N
Long Distance Migrant: N
Lacustrine Habitat(s): Shallow water
Special Habitat Factors: Benthic
Habitat Comments: This species is found in a broad range of habitats demonstrating a tolerance to habitat modification. It can be found in freshwater river drainages and tributaries, lakes and permanent artificial water bodies.
Economic Attributes Not yet assessed
Management Summary Not yet assessed
Population/Occurrence Delineation
Group Name: Freshwater Snails

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 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: Unlike most freshwater mussels [possibly excepting Uniomerus tetralasmus (Say, 1831) (see Isley, 1914)], some freshwater pulmonates are able to survive in intermittent streams and ponds by settling into sediment on the bottom and aestivating in otherwise dry or frozen conditions. Some species (e.g. Stagnicola spp.) may form a sheet of mucus just within the aperture called an epiphragm that effectively seals the snail from harsh external conditions (Jokinen, 1978; Brown, 1991). For ephemeral or intermittent water species, it may be particularly difficult to define the limits of an occurrence. Movement out of the water for the purposes of aestivation is on the order of cm (Jokinen, 1978), not m or km, so this behavior should not affect separation distance between occurrences. Species that may be found in intermittent waters include: Aplexa elongata, Fossaria bulimoides, F. dalli, F. modicella, F. obrussa, F. parva, Gyraulus circumstriatus, G. crista, G. parvus, Laevapex fuscus, Physa vernalis, Physella gyrina, Planorbella campestris, Planorbula armigera, Stagnicola caperata, S. elodes, S. exilis.
Separation Barriers: Separation barriers are largely based on permanent hydrological discontinuity between water bodies, with distances of 30 meters or greater between maximum high water marks constituting a separation barrier. Additional barriers are chemical and/or physical and include any connecting water body (regardless of size) with one or more of the following on a permanent basis: no dissolved calcium content, acidity greater than pH 5, lack of dissolved oxygen, extremely high salinity such as that found in saline lakes and brine waters, or temperature greater than 45

An additional physical barrier, particularly for flowing water, is presence of upland habitat between water connections. High waterfalls and anthropogenic barriers to water flow such as dams are barriers as they limit movement in an upstream direction.

Separation Distance for Unsuitable Habitat: 2 km
Separation Distance for Suitable Habitat: 2 km
Alternate Separation Procedure: Freshwater cave species (mostly prosobranchs) may occur near entrances to very deep in cave systems with specimens occurring on the undersides of small stones in riffle areas (Hershler et al., 1990). For cave species, separation distance cannot often be determined accurately due to varying degrees of accessibility to occupied cave habitat. In these instances, each cave where an observation or collection was recorded (see Minimum EO Criteria, above) constitutes an element occurrence regardless of separation distance. Multiple caves within a single hydrological cave system are each considered separately. Caves with multiple entrances and passages known to be connected, but with connecting passages too small or unsafe for human entry shall be treated as a single element occurrence when the non-negotiable portion of the cave is thought to be less than approximately 300 m linear length. Species known to occur in caves include: Amnicola cora, Antrobia spp., Antrobis spp., Antroselates spp., Dasyscias spp., Fontigens aldrichi, F. antroecetes, F. bottimeri, F. morrisoni, F. nickliniana, F. orolibas, F. prosperpina, F. tartarea, F. turritella, Holsingeria spp., Phreatodrobia spp., Stygopyrgus spp.
Separation Justification: Freshwater snails have adapted to most North American habitats including permanent standing, intermittent, and flowing waters. As a whole, pulmonates (previously Subclass Pulmonata) are better dispersers than prosobranchs (previously Subclass Prosobranchia). Pulmonates adapt better to changing temperature and oxygen concentration, resist desiccation better (use pulmonary respiration, store excreted nitrogen as urea, aestivate), and have faster crawling rates (including righting response and actual movement rate) than prosobranchs (Brown et al., 1998). Some species are more tolerant to adverse habitat conditions such as high pollution levels (e.g. Physella spp.), high altitude [e.g. Acroloxus coloradensis (Henderson, 1930)], underground cave pools and springs (e.g. Fontigens spp., Phreatodrobia spp.) and hot springs (e.g. Pyrgulopsis spp.).

Precise geographic distribution of many American freshwater snails is not known but presumably reflects past geological, geographic, and climatic change (Smith, 1989). Movements between isolated or inaccessible portions of water bodies is possible but dependent on outside, passive processes (e.g. rafting, periodic flooding, transport by vertebrates, introduction by humans). Long-distance dispersal is generally not considered when assigning separation distances as otherwise impracticably large separation distances would result.

Several factors contribute to limiting freshwater snail distribution but none apply across diverse habitats or taxa. Approximately 95% of all freshwater gastropods are restricted to waters with calcium concentrations greater than 3 mg/liter (Brown, 1991; for exceptions see Jokinen, 1983). Calcium uptake for shell construction requires energy expenditure (active transport) when calcium concentration is low, but is passive at higher concentrations (Greenaway, 1971). Typically, no known biotic or abiotic factors consistently limit the abundance or distribution of freshwater gastropods among sites (DeVries et al., 2003). At specific localities, limiting factors may include hardness, acidity, dissolved oxygen, salinity, high temperature, and food availability as associated with depth (Smith, 1989). Most species and the largest populations occur in hard, alkaline waters with normal range 20-180 ppm (Shoup, 1943; Harman, 1974). Snails are uncommon in habitats with surface acidity greater than pH 5 (see also Jokinen, 1983). Dissolved oxygen limits diversity so severely polluted waters (oxygen consumed by algae blooms) are often devoid of freshwater snails excepting pollution tolerant species. Because pulmonates can utilize atmospheric oxygen, they can exist under anaerobic conditions for longer time periods (Harman and Berg, 1971; Harman, 1974; McMahon, 1983). High salinity is limiting to freshwater gastropods and inland saline lakes generally lack an associated snail fauna. Most species (excepting hot springs species) are intolerant of temperatures greater than 45ºC (McDonald, 1969; van der Schalie and Berry, 1973), a condition rarely occurring naturally. Lower temperatures are less limiting as snails have been found foraging in ice-covered waters (Harman and Berg, 1971; Harman, 1974). Most species live in the shallows, (depths less than 3 m) where food abundance is greatest. As a result, drastic water fluctuations (draw-downs) may cause declines in snail populations (Hunt and Jones, 1972).

Any contiguous, occupied stretch of suitable flowing water habitat 2 km long or greater is considered an element occurrence. Two km was chosen based upon the limited active movement capabilities of most benthic invertebrates and observed home range of freshwater snails (J. Cordeiro, personal observation) as well as the relatively short life span of most species (five years for most stream species and two years for most pond species).

Date: 18Oct2004
Author: Cordeiro, J.
Notes: Prosobranchs: Neritidae: Neritina; Viviparidae: Campeloma, Cipangopaludina, Lioplax, Tulotoma, Viviparus; Ampullariidae: Marisa, Pomacea; Pleuroceridae: Elimia, Goniobasis, Gyrotoma, Io, Juga, Leptoxis, Lithasia, Pleurocera; Thiaridae: Melanoides, Tarebia; Bithyniidae: Bithynia; Hydrobiidae: Amnicola, Antrobia, Antrorbis, Antroselates, Aphaostracon, Balconorbis, Birgella, Cincinnatia, Clappia, Cochliopa, Cochliopina, Colligyrus, Dasyscias, Eremopyrgus, Floridiscrobs, Fluminicola, Fontelicella, Fontigens, Gillia, Heleobops, Holsingeria, Hoyia, Hydrobia, Lepyrium, Littoridina, Littoridinops, Lyogyrus, Notogillia, Onobops, Paludina, Phreatoceras, Phreatodrobia, Potamopyrgus, Pristinicola, Probythinella, Pyrgophorus, Pyrgulopsis, Rhapinema, Somatogyrus, Spilochlamys, Spurwinkia, Stiobia, Stygopyrgus, Taylorconcha, Texadina, Texapyrgu, Tryonia; Assimineidae: Assiminea; Pomatiopsidae: Pomatiopsis, Heterostropha; Valvatidae: Valvata

Population/Occurrence Viability
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
NatureServe Conservation Status Factors Edition Date: 25Nov2011
NatureServe Conservation Status Factors Author: Cordeiro, J.
Element Ecology & Life History Edition Date: 25Nov2011
Element Ecology & Life History Author(s): Cordeiro, J.

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