Northern Dwarf Siren, Gulf Hammock Dwarf Siren, Slender Dwarf Siren, Borad-striped Dwarf Siren
© 2001 John White (1 of 11)
Pseudobranchus striatus (LeConte, 1824)
Paul E. Moler1
1. Historical versus Current Distribution. Northern dwarf sirens (Pseudobranchus striatus) occur in the lower Gulf and Atlantic Coastal Plains from Orangeburg County, South Carolina (Folkerts, 1971), south to central peninsular Florida (Hernando and Volusia counties; Moler and Kezer, 1993), then west to Baker and Lee counties, Georgia (Goin and Crenshaw, 1949), and Walton County, Florida (Moler and Thomas, 1982). Three subspecies are recognized (Moler and Kezer, 1993; Crother et al., 2000): Gulf Hammock dwarf sirens (P. s. lustricolus), slender dwarf sirens (P. s. spheniscus), and broad-striped dwarf sirens (P. s. striatus). The current range of northern dwarf sirens is unchanged from their historical range, although populations have been lost as wetland habitats have been reduced through drainage of surface waters associated with residential, agricultural, and silvicultural development.
2. Historical versus Current Abundance. Northern dwarf sirens are often common in suitable habitats, but such habitats have been reduced through drainage of surface waters, and current numbers are reduced relative to their historical abundance.
3. Life History Features.
A. Breeding. Reproduction is aquatic.
i. Breeding migrations. Do not migrate. Northern dwarf sirens breed and permanently reside in the same aquatic habitats.
ii. Breeding habitat. Northern dwarf sirens live and breed in cypress (Taxodium sp.) or gum (Nyssa sp.) ponds and other shallow, acidic, wetlands of the flatwoods.
i. Egg deposition sites. Eggs are laid singly or in small bunches among aquatic vegetation (Noble, 1930).
ii. Clutch size. Unknown.
C. Larvae. Not well known. Petranka (1998) notes that larvae are similar to those of southern dwarf sirens (Pseudobranchus axanthus). Ashton and Ashton (1988) indicate Pseudobranchus larvae make take 2 yr to reach sexual maturity.
D. Juvenile Habitat. Same as adult habitat.
E. Adult Habitat. Most often associated with cypress or gum ponds and other shallow, acidic wetlands of the flatwoods. Unlike southern dwarf sirens (P. axanthus) northern dwarf sirens are not normally found among water hyacinths, which are typically absent from acidic wetlands of the flatwoods. Northern dwarf sirens have been collected from similar floating mats of frog's-bit (Limnobium spongium; Moler and Kezer, 1993), but they more typically inhabit decaying bottom vegetation and the soft, mucky soils of pond margins (Le Conte, 1824; Goin and Crenshaw, 1949).
F. Home Range Size. Unknown.
G. Territories. Unknown.
H. Aestivation/Avoiding Dessication. Northern dwarf sirens burrow into bottom sediments when wetlands dry (Harper, 1935; Goin and Crenshaw, 1949). They will remain buried until their wetland refills.
I. Seasonal Migrations. None.
J. Torpor (Hibernation). Northern dwarf sirens remain buried in mud and bottom debris during cold weather.
K. Interspecific Associations/Exclusions. Northern dwarf sirens occur sympatrically, but only occasionally syntopically, with southern dwarf sirens in northern peninsular Florida. In areas of sympatry, northern dwarf sirens are typically found in more acidic habitats than are southern dwarf sirens, but they are known to occur syntopically at a few sites (Moler and Kezer, 1993).
L. Age/Size at Reproductive Maturity. Unknown. Collections from Okefenokee Swamp, Georgia, suggest that northern dwarf sirens mature in < 1 yr (B. Freeman, personal communication). A maximum size of 203 mm was noted by Moler and Mansell (1986).
M. Longevity. Unknown.
N. Feeding Behavior. Unknown, but probably similar to that of southern dwarf sirens.
O. Predators. Unknown. Southern banded water snakes (Nerodia fasciata), black swamp snakes (Seminatrix pygaea), mud snakes (Farancia abacura), and crayfish snakes (Regina sp.) are common associates and likely prey on northern dwarf sirens. Various species of wading birds are likely major predators on Pseudobranchus, especially when dwarf sirens are concentrated by falling water levels. Predaceous fish are also probable predators.
P. Anti-Predator Mechanisms. Flight. Pseudobranchus are slippery and thus may escape when gripped. When seized, Pseudobranchus may produce high-pitched squeaks, but the utility of vocalizations as an anti-predator mechanism is unknown.
Q. Diseases. Unknown.
R. Parasites. Unknown.
4. Conservation. The current range of northern dwarf sirens is unchanged from their historical range, although populations have been lost as wetland habitats have been reduced through drainage of surface waters associated with residential, agricultural, and silvicultural development. Northern dwarf sirens are often common in suitable habitats, but such habitats have been reduced through drainage of surface waters, and current numbers are reduced relative to their historical abundance. Northern dwarf sirens are considered Threatened in South Carolina (www.dnr.state.sc.us).
1Paul E. Moler
Literature references for Amphibian Declines: The Conservation Status of United States Species, edited by Michael Lannoo, are here.
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