Regularity: Regularly occurring
Global Range: Scattered distribution in isolated wetlands, primarily on the Atlantic coastal plain from Georgia to southeastern Massachusetts. Especially spotty distribution in the southern portion of the range; more concentrated from New Jersey north. Several disjunct populations in the Midwest, mostly Illinois.
Comments: Seasonally saturated to flooded acidic sands and peat of shores/margins of freshwater ponds, swales, wet meadows, and depressions; also sometimes occurs in analogous anthropogenic habitats such as wet railroad ditches. This species is a heliophyte that requires open sites. A preferred (though rare) habitat appears to be natural depression wetlands with fluctuating water levels, where this species occurs in the area between low and high water.
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 21 - 80
Comments: Approximately 75-80 occurrences are presumed extant rangewide, scattered over 15 states. An additional 60-65 occurrences are believed historical or extirpated.
It is possible that the species' limited distribution is driven by dispersal limitation rather than habitat limitation.
Life History and Behavior
Presumably dispersed by waterfowl, as seeds are small (but larger than dust-sized).
National NatureServe Conservation Status
Rounded National Status Rank: N3 - Vulnerable
NatureServe Conservation Status
Rounded Global Status Rank: G3 - Vulnerable
Reasons: This species' range includes most of the eastern portion of the United States, but populations are widely scattered across that range. It is not common in any state, and has been extirpated or possibly extirpated in at least 5 states. The species has a specific habitat preference (seasonal, ground water-driven depressional wetlands); this habitat is sensitive to disturbance and is frequently threatened by draining and filling for agriculture and development. Recent droughts in the southeast have also caused declines in habitat availability and quality there.
Global Long Term Trend: Decline of 30-50%
Comments: Habitat has experienced non-trivial reduction from its historical extent, but loss is probably not greater than 50%.
Degree of Threat: Very high - medium
Comments: Alteration of pond hydrology is the primary threat to this species; attempts to drain the ponds and depressions where it occurs are frequent. Recreational use of shorelines is also an issue. In South Carolina (and likely some other nearby states as well), ephemeral wetlands, especially depressions, are severely threatened by the recent 20-30 year drought cycle - these droughts have led to lowered water tables and the seeding in of loblolly, sweet gum, and in some cases slash pine (B. Pittman pers. comm. 2010).
Biological Research Needs: Monitor hydrology of ponds.
Names and Taxonomy
Comments: Distinct species.
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