Marbled Salamander (Ambystoma opacum)

Marbled Salamander (Ambystoma opacum)

Photo © by Dave Huth, some rights reserved. Click image for licensing information.

Marbled Salamander (Ambystoma opacum)

Photo © by Dave Huth, some rights reserved. Click image for licensing information.

Marbled Salamander (Ambystoma opacum)

Photo © by Dave Huth, some rights reserved. Click image for licensing information.

Marbled salamander, Maple Flat Ponds, Virginia

© Steven David Johnson (All Rights Reserved)
Contact Steven David Johnson for image licensing

Marbled salamander, Maple Flat Ponds, Virginia

© Steven David Johnson (All Rights Reserved)
Contact Steven David Johnson for image licensing

Marbled salamander, Maple Flat Ponds, Virginia

© Steven David Johnson (All Rights Reserved)
Contact Steven David Johnson for image licensing

Marbled salamander, Maple Flat Ponds, Virginia

© Steven David Johnson (All Rights Reserved)
Contact Steven David Johnson for image licensing

Marbled salamander, Maple Flat Ponds, Virginia

© Steven David Johnson (All Rights Reserved)
Contact Steven David Johnson for image licensing

Marbled Salamander (Ambystoma opacum) - juvenile

Juvenile
Photo © by Dave Huth, some rights reserved. Click image for licensing information.

Video of juvenile marbled salamander
© Steven David Johnson (All Rights Reserved)

Contact Steven David Johnson for image licensing

This salamander is sexually dimorphic. Both male and female have black dorsal ground coloring; the bands on the female are gray or silver, and those on the male are white. the sides and the venter are black as well. They are generally short-tailed, stocky and broad-headed (Bartlett & Bartlett 1999).

A. opacum is the most strongly dimorphic of the ambystomatids. They are capable of burrowing, but they rather remain closer to the surface except for seasons of extended drought (Bartlett & Bartlett 1999).

Global Range: (200,000-2,500,000 square km (about 80,000-1,000,000 square miles)) Range extends from southern New Hampshire southward to northern Florida, west through southeastern New York to the southern Lake Michigan region, and south to eastern Oklahoma, eastern Texas, and the Gulf Coast. The species is absent from most of the Appalachian Mountains.

A. opacum inhabits sandy and gravelly areas of mixed deciduous woodlands (especially oak-maple and oak-hickory).

They require ponds or swamps in wooded areas for breeding, and during the breeding season, they can be found under logs and rocks – areas that are generally drier (DeGraaf & Rudis 1983).

Comments: Marbled salamanders live in various wooded habitats, near swamps or vernal pools. They are more tolerant of dry habitats than are most salamanders and can be found on rocky bluffs and slopes and wooded sand dunes. Adults are entirely terrestrial and spend most of their time under surface objects or underground. Eggs are laid in forest depressions such as vernal pool basins and sometimes at the edges of permanent ponds, swamps, and slow-moving streams, in sites that lack standing water in late summer or early fall but are inundated by fall rains and generally hold standing water through winter and into at least early summer of the next year. Oviposition sites typically are in mineral soil beneath protective cover of leaf litter, logs, detritus, or rocks.

Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites). Adults migrate seasonally between upland nonbreeding habitat and breeding sites. Migration distances generally are less than a few hundred meters. Individuals may migrate a short distance from a pool immediately after breeding, then continue migration after a period of winter inactivity.

Mating and egg deposition occur in late summer or early fall (August-November; earlier in the north than in the south). Mating often occurs before the female arrives at pond-basin nesting areas (Krenz and Scott, 1994, Herpetologica 50:46-50). Females deposit single clutches of up to about 250 eggs, which are attended by the female until the nest is flooded (female commonly deserts nest if disturbed before flooding). Larvae hatch in fall (usually) or as late as spring, depending on when rains flood the nest. Larvae metamorphose in spring or early summer and move into upland habitats. Most first-time breeders are at least a few years old. Maximum life-span is at least 11-12 years.

In South Carolina, reproductive success varied among different years; little or no recruitment occurred during drought periods (Pechmann et al. 1991). Food limitation may reduce individual female reproductive output (Scott and Fore 1995, Herpetologica 51:462-471).

Comments: Many local breeding sites have been eliminated by conversion of habitat to intensive human uses, and such loses are ongoing (Petranka 1998). However, a large number of stable populations exist, the overall rate of decline probably is less than 10 percent over 10 years or three generations.

A. opacum start to migrate to their breeding areas in the fall (generally in September). An average of 100 egss are laid in shallow depressions under surface material. They are then washed into the water to hatch. The eggs hatch at different times under different conditions. If the eggs are submerged, they will hatch in the fall or early winter. If there is no rain, the eggs will hatch in the spring. The larval period is affected by differing conditions as well. If the eggs hatch in the spring, their metamorphosis will be slower, transforming into their terrestrial form in late May to June. If there is a higher temperature and an abundance of food, metamorphosis will be hastened (DeGraaf & Rudis 1983).

Diet consists of eat arthropods, worms and mollusks. Larvae eat insects, crustaceans, and other small invertebrates. They can also be cannibalistic (DeGraaf & Rudis).

Threats: Threats to local populations likely include intensive timber harvesting practices that reduce canopy closure, understory vegetation, uncompacted forest litter, or coarse woody debris (moderately to well-decayed) in areas surrounding breeding sites (deMaynadier and Hunter 1999). Breeding sites are vulnerable to destruction and degradation through draining and filling, and many are being isolated by habitat fragmentation, which could eventually result in deleterious levels of inbreeding and reduced chances of reestablishment of locally extripated populations. Thousands of local populations already have been eliminated by habitat loss, and more will be lost in the future (Petranka 1998).

Sources:
NatureServe and  AmphibiaWeb via Encylopedia of Life

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