Hottonia inflata - Ell.
Other English Common Names: American Featherfoil
Other Common Names: American featherfoil
Taxonomic Status: Accepted
Related ITIS Name(s): Hottonia inflata Ell. (TSN 24048)
Unique Identifier: ELEMENT_GLOBAL.2.143297
Element Code: PDPRI06010
Informal Taxonomy: Plants, Vascular - Flowering Plants - Primrose Family
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Dicotyledoneae Primulales Primulaceae Hottonia
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Concept Reference
Concept Reference: Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Concept Reference Code: B94KAR01HQUS
Name Used in Concept Reference: Hottonia inflata
Taxonomic Comments: Distinct species.
Conservation Status

NatureServe Status

Global Status: G4
Global Status Last Reviewed: 02Aug1994
Global Status Last Changed: 02Aug1994
Rounded Global Status: G4 - Apparently Secure
Nation: United States
National Status: N4

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 (S2), Arkansas (SNR), Connecticut (S3), Delaware (S2), Florida (SNR), Georgia (S1), Illinois (S2S3), Indiana (S2), Kentucky (S4?), Louisiana (SNR), Maine (S1), Maryland (S1), Massachusetts (S3), Mississippi (S1), Missouri (S2), New Hampshire (S1), New Jersey (S1), New York (S2), North Carolina (S1?), Ohio (SH), Oklahoma (S2), Pennsylvania (SX), Rhode Island (S1), South Carolina (S1), Tennessee (S2), Texas (S3), Virginia (S3), West Virginia (S1)

Other Statuses

NatureServe Global Conservation Status Factors

Range Extent Comments: Occurs disjunctly in the Atlantic Coastal Plain from Maine, Pennslyvania, New York and New Jersey to northern Florida; the Mississippi Embayment from Louisiana and Texas to Ohio, Illinois, Oklahoma and Missouri; the Lake Ontario Plain of Ohio.

Number of Occurrences:  
Number of Occurrences Comments: Likely over one hundred occurrences.

Overall Threat Impact Comments:

Primary threats to the featherfoil include wetland drainage, hydrological alterations and water quality degradation. Such threats have been noted from many states, including Virginia (Ludwig pers. comm.), New Jersey (Snyder 1989), Missouri (Ladd pers. comm.) and the entire New England Coastal Plain (Frost pers. obs.). Similar problems (dredging and development) pose threats to one of the two extant sites in Connecticut (CT NDDB 1989). Loss of habitat through agricultural development and other unspecified destruction in Indiana has eliminated the species from all but two extant sites (IN NHP 1989).

Guthrie (1987) listed the major threats to the Reelfoot Lake, Tennessee population as being mechanical in nature, derived by man (i.e., dredging and cookie cutters). In addition, Somers (pers. comm.) stated that siltation from erosion of farmland is a serious threat to the population today. At current siltation rates, the lake is expected to be filled in 20-50 years (Somers pers. comm.).

Competition from other vegetation may pose threats at some sites. At a single New Jersey location, it is believed that Phragmites may become a problem in outcompeting Hottonia inflata for available resources (NY NHP 1989).

Serious flooding at time of maturation (spring) is potentially disastrous to Hottonia populations and may eliminate an entire cohort of plants at a given site, as well as destroy habitat through destruction of beaver dams, siltation, eutrophication and substrate alterations. Since mature plants are top-heavy, they are exceedingly susceptible to injury and uprooting during periods of high water when water levels and currents are increased. Such a loss of entire cohorts has been observed at several sites in North Carolina following severe floods (Frost pers. obs.). Smaller, half-grown plants are typically left intact. Loss of water control structures, such as beaver dams, will effectively destroy suitable habitats in small river and creek systems. Levees built along the lower Mississippi river have made old oxbow lakes suitable habitat as they are no longer subject to serious flooding.

Short-term Trend: Relatively Stable (<=10% change)
Short-term Trend Comments: Populations are stable and may be increasing slightly due to restoration of beavers into historic habitat.

Intrinsic Vulnerability Comments: Susceptible to spring flooding.

Other NatureServe Conservation Status Information

Global Range: Occurs disjunctly in the Atlantic Coastal Plain from Maine, Pennslyvania, New York and New Jersey to northern Florida; the Mississippi Embayment from Louisiana and Texas to Ohio, Illinois, Oklahoma and Missouri; the Lake Ontario Plain of Ohio.

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

U.S. & Canada State/Province Distribution
United States AL, AR, CT, DE, FL, GA, IL, IN, KY, LA, MA, MD, ME, MO, MS, NC, NH, NJ, NY, OH, OK, PAextirpated, RI, SC, TN, TX, VA, WV

Range Map
No map available.

U.S. Distribution by County Help
State County Name (FIPS Code)
AL Dallas (01047), Greene (01063), Macon (01087)*, Madison (01089), Montgomery (01101)*, Perry (01105)
CT Fairfield (09001), Hartford (09003)*, Middlesex (09007), New Haven (09009), New London (09011), Windham (09015)
DE Kent (10001), New Castle (10003)
GA Bartow (13015)*, Laurens (13175)
IN Clark (18019), Dubois (18037), Pike (18125), Posey (18129), Scott (18143), Vanderburgh (18163)*, Warrick (18173)*
MA Barnstable (25001), Bristol (25005), Dukes (25007), Essex (25009), Middlesex (25017), Norfolk (25021), Plymouth (25023), Suffolk (25025)*, Worcester (25027)
MD Caroline (24011), Charles (24017), Dorchester (24019)*, Kent (24029), Queen Annes (24035), Talbot (24041)
ME Washington (23029)*, York (23031)
MO Bollinger (29017), Butler (29023), Cape Girardeau (29031)*, Carter (29035), Dunklin (29069), Franklin (29071)*, Jefferson (29099)*, Reynolds (29179), Ripley (29181)*, Shannon (29203), St. Charles (29183)*, St. Louis (29189)*, St. Louis (city) (29510)*, Stoddard (29207), Wayne (29223)
MS Coahoma (28027)*, Grenada (28043), Oktibbeha (28105), Quitman (28119)*, Tunica (28143)
NC Bertie (37015), Dare (37055), Edgecombe (37065)*, Gates (37073), Halifax (37083), Johnston (37101), Lenoir (37107), Martin (37117), Tyrrell (37177)
NH Rockingham (33015), Strafford (33017)
NJ Bergen (34003)*, Cape May (34009), Essex (34013)*, Hudson (34017)*, Middlesex (34023)*, Monmouth (34025)*, Morris (34027), Ocean (34029)*, Passaic (34031)*, Salem (34033), Union (34039)*
NY Kings (36047)*, Nassau (36059)*, New York (36061)*, Orange (36071), Putnam (36079)*, Queens (36081)*, Richmond (36085), Rockland (36087), Suffolk (36103), Westchester (36119)
OH Scioto (39145)*
OK Bryan (40013), Choctaw (40023), McCurtain (40089)
PA Bucks (42017)*, Sullivan (42113)*
RI Bristol (44001), Newport (44005), Providence (44007), Washington (44009)
SC Williamsburg (45089)
TN Decatur (47039), Hardin (47071), Lake (47095), Lauderdale (47097), Marion (47115), Montgomery (47125), Obion (47131), Shelby (47157)
WV Mason (54053)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
01 Maine Coastal (01050002)+*, Piscataqua-Salmon Falls (01060003)+, Merrimack (01070002)+, Concord (01070005)+, Merrimack (01070006)+, Lower Connecticut (01080205)+, Farmington (01080207)+*, Charles (01090001)+, Cape Cod (01090002)+, Blackstone (01090003)+, Narragansett (01090004)+, Pawcatuck-Wood (01090005)+, Quinebaug (01100001)+, Thames (01100003)+, Quinnipiac (01100004)+, Housatonic (01100005)+*, Saugatuck (01100006)+
02 Hudson-Wappinger (02020008)+, Lower Hudson (02030101)+, Bronx (02030102)+, Hackensack-Passaic (02030103)+, Sandy Hook-Staten Island (02030104)+, Raritan (02030105)+*, Northern Long Island (02030201)+, Southern Long Island (02030202)+, Long Island Sound (02030203)+*, Crosswicks-Neshaminy (02040201)+*, Delaware Bay (02040204)+*, Brandywine-Christina (02040205)+, Cohansey-Maurice (02040206)+, Broadkill-Smyrna (02040207)+, Mullica-Toms (02040301)+*, Great Egg Harbor (02040302)+*, Lower West Branch Susquehanna (02050206)+*, Chester-Sassafras (02060002)+, Choptank (02060005)+, Lower Potomac (02070011)+
03 Lower Roanoke (03010107)+, Ghowan (03010203)+, Albemarle (03010205)+, Upper Tar (03020101)+*, Upper Neuse (03020201)+, Middle Neuse (03020202)+, Black (03040205)+, Lower Oconee (03070102)+, Etowah (03150104)+*, Lower Tallapoosa (03150110)+*, Cahaba (03150202)+, Middle Alabama (03150203)+, Middle Tombigbee-Lubbub (03160106)+, Noxubee (03160108)+
05 Raccoon-Symmes (05090101)+, Little Scioto-Tygarts (05090103)+*, Lower Wabash (05120113)+*, Muscatatuck (05120207)+, Patoka (05120209)+, Lower Cumberland (05130205)+, Silver-Little Kentucky (05140101)+, Lower Ohio-Little Pigeon (05140201)+*, Highland-Pigeon (05140202)+
06 Guntersville Lake (06030001)+, Wheeler Lake (06030002)+, Lower Tennessee-Beech (06040001)+
07 Peruque-Piasa (07110009)+*, Cahokia-Joachim (07140101)+*, Meramec (07140102)+*, Upper Mississippi-Cape Girardeau (07140105)+*, Whitewater (07140107)+
08 Lower Mississippi-Memphis (08010100)+, Obion (08010202)+, Upper St. Francis (08020202)+, Lower St. Francis (08020203)+, Little River Ditches (08020204)+*, Coldwater (08030204)+, Yalobusha (08030205)+
10 Lower Missouri (10300200)+*
11 Upper Black (11010007)+, Current (11010008)+, Eleven Point (11010011)+, Clear Boggy (11140104)+, Kiamichi (11140105)+, Upper Little (11140107)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
Technical Description: Hottonia inflata is an aquatic, glabrous plant with submersed stems 0.3-1.5 m long and numerous crowded leaves, branched apically into 1-15 emersed hollow, inflated, leafless, flowering stems, 3-20 cm long, 0.3-2.0 cm wide, contracted at the nodes. Submersed leaves are clustered at the base of the flowering stems and scattered along the rooting and floating vegetative stems. They are oblong in outline and are pectinate in form, 4-18 cm long, 0.8-5.0 cm wide. The rachis is 1-6 mm wide, with divisions 0.3-1.5 mm wide. Flowers are white, pedicilate, subtended by foliaceous bracts and occur in whorls at the nodes of flowering stems (Decker 1974). The capsule is subglobose and many-seeded, the five valves cohering at the base and the summit (Correll and Johnston 1970).
Ecology Comments:

The species is believed to be a winter annual, based initially on observations made in Massachusetts by Knowlton (1911). Recent work by Frost (pers. comm.) has suggested that the species may, in fact, require two years to complete its life cycle, with the seeds lying dormant in mud for a full year before germinating. Dormancy may be broken prematurely by lying in the mud of a dry, intermittent pool or shoreline and being exposed to the warmth of the sun (Frost pers. obs.).

Hottonia inflata is highly ephemeral (Mitchell and Sheviak 1981). Its seeds are shed during a 2-3 week period with the plant disintegrating soon thereafter, typically in July (Frost pers. comm., Knowlton 1911). Seeds float on the water surface for a period after dehiscing from the plant (due to surface tension), then sink to the muddy bottoms of the ponds.

Plants typically decay in mid June to August, depending on locality. Seeds germinate on the muddy bottom of streams, backwaters and protected lakes in midsummer of the following year (July - August) (Frost pers. obs.). Snyder (pers. comm.) observed newly-germinated plants at the bottom of an intermittent pool in the fall of the year in New Jersey. The plants were found growing beneath the shadows of fallen trees where other vegetation emerging from the seedbank in the dried-up pool was not abundant. Plants of this size (the size of a quarter) may be observed in this habitat in September (Frost pers. obs.).

Plants grow and develop during the winter months, protected from the winter cold by the water (Guthrie 1987). In Massachusetts, near the north end of its range, inflated flower-stalks begin to develop in May with the first flowers appearing by the end of May, reaching fullest development by the middle of July (Knowlton 1911). In Tennessee, farther to the south, plants flower in April and May, reaching fullest development in early May (Guthrie 1987). Racemes continue to elongate and produce flowers until the end of June or July (Frost pers. obs.).

Hottonia inflata is apparently the beneficiary of a commensal relationship with beaver (Castor canadensis) (Frost pers. comm., 1984). Beaver ponds produce the essential, stable, shallow pond habitat needed for the survival of the plants.

The ponds also provide feeding and nesting stations for mallards and wood ducks, the only common waterfowl in these habitats during the May-July seed dispersal period. These two species are believed to be the primary dispersers for Hottonia. Flushing of duck feathers with water has shown that mallards and wood ducks, both of which utilize beaver ponds as feeding and resting stations, pick up seeds in their feathers during the period when seeds are floating on the surface (Frost pers. obs.). Frequent flights to other pools and backwaters facilitate the spread of Hottonia. Although wood ducks also eat the plants, inadvertently consuming the tiny seeds (Guthrie 1987), seeds of the plant apparently cannot make it through their digestive system unscathed (Frost pers. obs.). The delicate seed coats do not allow the passage of seeds in this manner.

Beavers are also likely distributors of seeds. An observation of a stream system over a number of years in North Carolina revealed that Hottonia appeared in the pools of successively new, upstream beaver ponds within a year after their formation (Frost pers. obs.). It is believed that beavers spread the seeds during the transportation of pond mud for building and repairing dams and lodges.

These two dispersal mechanisms are but a fraction of those proposed. Dispersal within a given aquatic system may be achieved through an array of some 40 mechanisms that are designed to repopulate known habitat and explore new sites (Frost 1984).

Hottonia inflata has a long tradition of being present at a given site in a given year, but being absent in the next. In fact, the species may be absent for as many as five years before reappearing again in the same locality (Gordon 1984). Frost (pers. comm.) has suggested that this appearance/disappearance regime may be an artifact of its two-year life cycle, and of reintroduction through haphazard and periodic seed dispersal by ducks.

At one site in North Carolina, Frost (pers. obs.) observed vast numbers of individuals one year, but found it absent in the next. In the following year, however, the species reappeared in large numbers. Records showed that a serious, damaging flood occurred during a past year, probably eliminating the second-year cohort. Mature plants are extremely top-heavy and are exceedingly susceptible to flood damage at the critical time of initial seed dispersal. Based on these observations and stratification experiments, Frost (pers. comm.) believes that Hottonia seeds probably do not remain viable in the seed bank of mud-bottomed pools for long periods.

This habit of appearing and disappearing has also probably led to the mistaken belief that the species is common. Plotted distribution maps tend to show many records throughout the entire range of the species, but many represent one-time sightings and are largely historic occurrences (Frost pers. comm.).

There seems to be a marked difference in overall numbers of individuals and populations in various portions of the country. In the North, it is typically less common than in the south, although in many states the distribution is poorly known. In Texas, however, Hottonia inflata has been described as a weedy species, having the "potential nuisance value of the water hyacinth" (Correll and Johnston 1970), although Orzell (pers. comm.) and Frost (pers. comm.) believe that it does not reach a nuisance level within the state. The sparsity of occurrences in the north is probably due to habitat destruction and persistence of snow cover on ponds. While the plant thrives under clear ice which admits sunlight, snow-covered ice reduces the photosynthetic ability for the species, demarcating the northern limit of its range (Frost pers. comm.). This phenomenon is well-known for an associate of Hottonia in Illinois, a species of Azolla, which is known to be eliminated from the northern portions of its range by severely cold and snowy winters (Schwegman pers. comm.).

Habitat Comments: The species occurs disjunctly along the Atlantic Coastal Plain from Maine, Pennsylvania, New York and New Jersey to northern Florida, the Mississippi Embayment from Louisiana and Texas to Ohio, Illinois, Oklahoma and Missouri, and the Lake Ontario Plain of Ohio (Guthrie 1987, Correll and Johnston 1970). For a detailed distribution map of the species, see Guthrie (1987).

Historical and extant records often place Hottonia inflata populations in beaver ponds. In fact, about half of all historical collections were made from this habitat (Frost pers. comm.). In addition, beaver ponds are believed to have accounted for 95% of all presettlement habitat. Additional historical records exist for natural populations occurring within interdunal pools on the Atlantic Coastal Plain, oxbow lakes in the lower Mississippi Valley (now protected from flooding by levees) and lakes and pools within the glaciated portion of Connecticut and Massachusetts. Wherever it occurs, the species apparently requires shallow pools with stable water levels. Beaver ponds, whose low dams regulate water levels, appear to provide ideal habitat (Frost pers. obs.).

New York populations are known from ditches, ponds, kettle holes, and swale pools, principally in shallow water (up to 4 feet) (NY NHP 1989a, 1989b) or stranded on mud (Mitchell and Sheviak 1981). Associated plant species at a pond within a disturbed deciduous woodland include Glyceria canadense, Acer rubrum, Cephalanthus occidentalis and Vaccinium corynikosum (NY NHP 1989a,1989b). At a kettle hole site surrounded by oak woods, associates include red maple and tupelo (NY NHP 1989b). The species occurs in the southeast corner of the state in the Lower Hudson Valley and on Long Island.

New Jersey populations occur in wooded swamps (both intermittent and perpetual) and ponds (NJ NHP 1989). Currently, there are three extant and 17 historical sites within the state (Snyder 1989). The distribution within the state is disjunct, with populations known from the coastal plain of Salem and Cape May Counties, as well as the Piedmont portion of the state. In the coastal plain, populations occur in permanent pools, with some populations having been documented from the same site for over a century (Snyder pers. comm.). The Salem County site is a pond possessing two populations, each growing in water of greater than 1 m in depth (Schuyler pers. comm.). In the summer of 1989, the stands measured roughly 5m X 5m and 2m X 13m in size. In the Piedmont, however, the species is known from deep, slow-moving creeks and streams (Snyder pers. comm.). The Piedmont habitat has been largely destroyed through urbanization.

Based on historic records, Brockett and Cooperrider (1983) described the habitat in Ohio as ponds and wet ditches. The two extant Ohio populations, known from ponds, occur in Ashtabula and Scioto Counties in the northeast and southcentral portions of the state. The Scioto County site is a small, open pond in a depression where clay was scooped out for an industrial purpose many years ago (Frost pers. comm.). The owners of the land cut down all of the trees in the area a few years ago. The other site in Ashtabula county is a deep pond in deciduous forest with plants occurring at depths of 4 feet (Snyder 1989).

Populations in Indiana were known from several historical sites, typically composed of wetland habitats such as scuffle ponds, Populus-Taxodium or Quercus lyrata swamps and wet sand (IN NHP 1989). Extant populations, however, are limited to two sites.

The largest Tennessee population occurs in Reelfoot Lake, a lake that was formed by the New Madrid earthquake of 1811 (Somers pers. comm., Guthrie 1987). At this site, H. inflata occurs within the protected waters of roadside ditches, and within a band of giant cutgrass (Zizaniopsis) around islands. Along the shoreline, the species grows with Taxodium and other emergent vegetation (TN ESD 1989, Guthrie 1987). Guthrie (1989) listed this species as a member of the submerged aquatic community, associated with Potamogeton spp., Ceratophyllum demersum, Ludwigia peploides ssp. glabrescens, Utricularia spp., Cabomba caroliniana, Heteranthera dubia, Elodea nuttallii and Ranunculus flabellaris. Hottonia plants typically occur in full sun or partial shade (Guthrie 1987). Other sites in Tennessee include unprotected sloughs and swamps (Somers pers. comm.).

Decker (1974) stated that the species occurs in Mississippi in freshwater ponds, slow-moving river swamps, lakes, pools, rivers, ditches and canals, chiefly on the coastal plain. Gordon (1984) listed a single site from the state. At this site, the habitat is described as an oxbow lake with cypresses, surrounded by cultivated fields (MS NHP 1988) now in rice production (Gordon pers. comm.). Individual plants occur in water under 0.5 m in depth. Frost (pers. comm.) found an additional population in an isolated oxbow within the Mississippi River Valley of Mississippi.

Hottonia inflata is found in eastern Texas, growing abundantly in a few lakes, pools and ditches (Correll and Johnston 1970). Orzell (pers. comm.) collected the species from the edge of a swamp within the post oak belt of east-central Texas (Leon County). Associates included Planera aquatica and Cephalanthus occidentalis. This is one of only two regions (the other being southern Virginia and northeastern North Carolina) where the species is relatively secure (Frost pers. comm.).

Hottonia is known from a single locality in Alabama, either a cypress or tupelo/gum sinkhole pond in a deciduous forest. The water within the sinkhole is dark in color, a result of the leaching of leaf litter. Associates include two other rare Alabama plants, Ranunculus flabellaris and Armoracia aquatica (Haines pers. comm.).

To date, Hottonia inflata has not been tracked as a rare species in Missouri. This will change, as the state recently adopted the species for state listing. There is concern that the extant populations are diminishing in size, sometimes precipitously (Ladd pers. comm.). Ladd (pers. comm.) had observed the species at three sites in the state, two being a bald cypress/water tupelo swamp and the other a relictual sinkhole pond. Water within the habitat was typically laden with tanins.

Schwegman (pers. comm.) stated that the species is known from the southern third of Illinois. At the extreme southern end of the state it is known to occur in the water tupelo/bald cypress swamps (Ladd pers. comm., Schwegman pers. comm.). Farther to the north, near the latitude of St. Louis, Missouri, the typical habitat is a wetland marsh. Typical associates at both sites include duckweeds, Limnobium spongium and Azolla. The species has been observed in drainage ditches within the state (Schwegman pers. comm.). A single protected population occurs within the Little Black Slough SNA in the Cache River Valley of southern Illinois (Frost pers. comm.).

Economic Attributes Not yet assessed
Management Summary
Stewardship Overview:

Monitoring should be conducted of extant populations in order to determine whether populations are maintaining themselves, expanding or decreasing under present management regimes. Threats to the species, such as silt levels, tendencies toward eutrophication, and surface and groundwater manipulations also need to be monitored with respect to population viability and size. Research should initially be centered around a range-wide status survey of the species in order to assess its true abundance and to locate all existing populations. Eutrophication, surface and groundwater manipulation, and siltation are the main management concerns that need to be addressed at each site. Protection of beavers, and consequently their ponds, may increase the amount of potential habitat and long-term survivability of Hottonia at a particular site.

Restoration Potential:

The near-extinction of beavers over much of their former range during the nineteenth and twentieth centuries probably decimated populations of Hottonia through the subsequent disappearance of their pond habitat. Only recently has the beaver reappeared over portions of its former range, creating essential habitat for Hottonia. However, over most of the area where the ranges of beaver and Hottonia coincide, beaver are trapped with ponds disintegrating a short period thereafter. In the rare situation where, in a small stream system, beavers can be protected, series of ponds appear to be maintained on a semi-permanent basis and Hottonia populations remain stable. Such a situation can be seen at Merchants Mill Pond State Park in North Carolina (Frost pers. obs.).

Burns (1984) believed that, because of its habit as a winter "annual", Hottonia inflata may be difficult to establish. Although this may be true in the northern part of its range, it apparently is not a problem in the south. In the northern portions of its range, thick winter ice with a heavy snow cover may be detrimental to growth in the winter months. Frost (1984) stated that roughly 40 mechanisms associated with featherfoil actively distribute the species into new and existing sites. Because its habitat is also frequented by ducks and beaver, dispersal and establishment should be relatively good, particularly in the middle and southern portions of its range.

Throughout much of its range, habitat has been destroyed through the elimination of stable beaver populations (Frost pers. comm.), as well as other destructive measures that eliminate habitat through surface groundwater manipulations (eg., dredging, ditching, tiling and filling of wetlands for farmland and other developmental causes). A curtailment in the destruction of these wetlands is necessary if enough habitat is to be protected.

Very few populations of this species have been protected by occurring within preserve boundaries. A single occurrence in Connecticut, although within the boundaries of The Nature Conservancy's Pequot Woods preserve is apparently still susceptible to dredging and development threats (CT NDDB 1989). Other protected sites include a population at Nags Head Woods Preserve in North Carolina, owned by The Nature Conservancy, and a population at the Little Black Slough SNA in Illinois (Frost pers. obs.). The Reelfoot Lake populations in Tennessee occur within the Reelfoot State Wildlife Management Area, Reelfoot Lake State Park (TN ESD 1989), and Reelfoot National Wildlife Refuge, but imposing threats exist for those occurrences primarily through siltation and possible future water level manipulations.

Preserve Selection & Design Considerations:

Since Hottonia inflata is an aquatic species, land protection must take into account, to some degree, the entire watershed at and above the point where the species occurs. The immediate aquatic habitat in which the species occurs should be a first priority in land protection. However, there is little use in protecting a given site if upstream land use threatens its integrity.

Small populations are probably largely ephemeral, appearing within newly created beaver ponds or other impoundments, then disappearing in subsequent years through the elimination of beaver (and the subsequent decay of dams) or extirpation of flowering populations by flood events. It may be suggested that the largest populations be targeted for protection, while the smaller, ephemeral populations simply be monitored. Little logic prevails in spending vast amounts of time or money purchasing small watersheds if there exists a strong likelihood that the population will be absent in a few years.

Protection of the species in riverine systems must address upslope and upstream erosion problems, since siltation is considered to be a major threat. The habitats preferred by Hottonia (ponds, lakes and river backwaters) are particularly susceptible to siltation due to the lack of existing cleansing actions similar to that occurring in river systems. The apparent preference toward habitats with slow-moving or stagnant waters underscores the need for erosion control. Similar protection from pollution (agricultural herbicides, nitrates, fertilizers, etc.) also needs to be assured.

Management Requirements:

Permanent survival of the species could probably be assured by provision of a safe complex of permanently protected beaver ponds in a small landscape in each state. Elimination of beaver from a particular beaver pond would ultimately lead to the elimination of the Hottonia occurrence through decay of the beaver dam.

The largest Tennessee population, occurring in Reelfoot Lake, is threatened by siltation resulting from farmland erosion (Somers pers. comm.). Erosion control within the watershed must be implemented in the near future before the lake completely fills or becomes too shallow (which should take between 20 and 50 years).

The provision of a safe haven for beaver could be achieved by closure of a particular state park, state preserve, state or national forest area, etc., to trapping of beavers (Frost pers. comm.).

Reduction in siltation should center on the agriculture lands upstream from the population in question. Highly erodible lands should be taken out of production and restored to natural cover (forest) or enrolled in the Conservation Reserve Program (CRP) or similar state programs, if available. Buffer strips along waterways of no less than 100 feet should be installed to reduce additional threats to water quality via siltation.

Techniques used for the reduction of siltation should also result in the lowering of fertilizer run-off from agricultural fields and eutrophication of aquatic habitats. Adopted management practices at Reelfoot Lake should take into account the need to minimize damage to the Hottonia population. Similar protective methodologies should eventually be implemented in all watersheds slated for protection.

Monitoring Requirements:

Monitoring should be undertaken within a given preserve in order to assess changes in individual numbers of Hottonia inflata over time. Since the species is an annual, vast fluctuations in numbers of individuals may occur from year-to-year. The apparent absence from a given site should not be immediately construed as the loss of the species, since the one-year seed dormancy may lead to alternating large and small populations or populations which may only appear every other year.

Monitoring of populations may lead to a better understanding of the effects that existing management practices, siltation, eutrophication, etc., have on the species.

Due to its seed dormancy requirement, Hottonia monitoring methodologies should be formulated so that information would be derived from both (even and odd year) cohorts. It may prove beneficial to monitor populations in two back-to-back years. Succeeding population monitoring of cohorts should take place every 5-10 years (Somers pers. comm.). If drawdown has occurred at a given site, population monitoring should be done more frequently, perhaps every 2 years, in order to insure that establishment, reproduction and population numbers remain constant. Since individuals of the species die down by mid-July leaving no evidence of their occurrence, monitoring programs should be established prior to that time so that population numbers can be best assessed.

Specific methodologies for monitoring populations of aquatic plants such as Hottonia, may not be well-developed. Individual counts of flowering stems may provide the best estimate of overall population size during a given year. While single-stemmed plants are most common, populations often occur with multiple stems arising from a single base. One method that has been used is to determine the average number of stems per individual in a few square meter plots using a floating meter square frame (Frost pers. comm.). This average figure could then be used to determine the overall size of the population by counting the entire number of flower heads. Seed formation is rather constant, the plants being autogamous, and may not have to be checked. Massive amounts of seed (averaging roughly 65,00 seeds per plant) were produced in all plants collected throughout the range of the species (Frost pers. obs.). Counts must be done during the short period of time when plants are visible, as decomposition of mature plants rapidly follows flowering.

Management Programs:

Efforts to curtail siltation at Reelfoot Lake in Tennessee have been moderately successful (Somers pers. comm.). Current management of the lake is being conducted largely by the USFWS and the Tennessee Wildlife Resources Agency. Recently, the Tennessee Wildlife Resources Agency has written a management plan for the lake which calls for a draw-down in order to oxidize the lake sediments and offset increasing anaerobic conditions brought on by eutrophication and siltation. This activity, however, may decimate the Hottonia population. Contact: Harold Hurst or Jim Johnson, Tennessee Wildlife Resources Agency, Jackson, TN. Telephone No. (901) 423-5726.

The USFWS completed an environmental impact statement for Reelfoot Lake this past July (see USFWS 1989). Several methodologies have been proposed as management practices, including management through (1) practices used in the past, (2) dynamic water fluctuations, (3) major drawdowns, (4) methodologies similar to current practices, but with lake levels at higher than present levels, (5) the raising of the lake level one foot, and (6) an integrated program of dynamic water fluctuations coupled with periodic major drawdowns (USFWS 1989). It is unknown if any of these management options have been exercised. Contact: Glenn Stanley, Assistant Manager, Reelfoot National Wildlife Refuge, Route 2, Highway 157, Union City, TN 38261. Telephone No. (901) 538-2481 or James Pulliam, Jr., Regional Director, USFWS, Southeast Region, 75 Spring Street SW, Atlanta, GA 30303.

Beaver, wood ducks, and the largest known stable population of Hottonia inflata are managed at Merchants Mill Pond State Park (3,000 acres), Gatesville, North Carolina. Contact: unknown.

Management Research Programs: Cecil Frost, at the University of North Carolina, has been working on the entire life history of this species throughout much of the species' range. Contact: Cecil Frost, 710 Underwood Avenue, Durham, NC 27701. Telephone No. (919) 493-5777.
Population/Occurrence Delineation Not yet assessed
Population/Occurrence Viability
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
NatureServe Conservation Status Factors Edition Date: 15Dec1990
NatureServe Conservation Status Factors Author: Ostlie, W. R. (MRO)
Management Information Edition Date: 01Feb1990
Management Information Edition Author: WAYNE R. OSTLIE & CECIL C. FROST
Element Ecology & Life History Edition Date: 05Nov1990
Element Ecology & Life History Author(s): OSTILE, W.

Botanical data developed by NatureServe and its network of natural heritage programs (see Local Programs), The North Carolina Botanical Garden, and other contributors and cooperators (see Sources).


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