Flatwoods Salamander

Ambystoma cingulatum

Description

The Ambystoma cingulatum (flatwoods salamander) is a slender, small-headed mole salamander that rarely exceeds 5 in (13 cm) in length when fully mature. Adult dorsal color ranges from black to chocolate-black with highly variable, fine, light gray lines forming a netlike or cross-banded pattern across the back. Undersurfaces are plain gray to black with a few creamy or pearl-gray blotches or spots. Sexual dimorphism (the existence of separable male and female forms) is only apparent in breeding males (swollen cloacal region) or in gravid (with fertilized eggs) females. Adults most closely resemble Mabee's salamander, A. mabeei, with which it shares part of its range in South Carolina. Mabee's salamanders are often more brownish; have light flecking concentrated on their sides rather than the overall pattern of the flatwoods salamander; and have a single row of jaw teeth as opposed to multiple rows in the flatwoods salamander. Although the flatwoods salamander closely resembles Mabee's salamander, it is most closely related to the ringed salamander (A. annulatum ), which occurs in portions of Arkansas, Missouri, and Oklahoma.

Flatwoods salamander larvae are long and slender, broad-headed and bushy-gilled, with white bellies and striped sides. They have distinctive color patterns, typically a tan mid-dorsal (middle of upper surface) stripe followed by a grayish black dorsolateral (back and sides) stripe, a pale cream mid-lateral (side) stripe, a blue-black lower lateral stripe, and a pale yellow ventrolateral (belly) stripe. The head has a dark brown stripe passing through the eye from the nostril to the gills.

Behavior

Before the breeding sites become flooded, the males and females court. The females lay their eggs (singly or in clumps) beneath leaf litter, under logs and sphagnum moss (grows in wet acid areas) mats, or at bases of bushes, small trees, or clumps of grass. Egg masses have also been found at the entrances of and within crayfish burrows. Embryos begin development immediately, but the egg must be inundated before it will hatch. Depending on when eggs are inundated, the larvae usually metamorphose (change into adult form) in March or April; the length of the larval period varies from 11-18 weeks.

The timing and frequency of rainfall are critical to the successful reproduction and recruitment of flatwoods salamanders. Fall rains are required to facilitate movements to the pond and winter rains are needed to ensure that ponds are filled sufficiently to allow hatching, development, and metamorphosis of larvae. In contrast, too much rainfall in the summer will keep pond levels from dropping below the grassy pond edge, as needed to provide dry substrate for egg deposition. This reliance on specific weather conditions results in unpredictable breeding events and reduces the likelihood that recruitment will occur every year.

Adult flatwoods salamanders leave the pond site after breeding. Studies have suggested a homing ability, based on data that salamanders exit the breeding pond near the point of their arrival; flat-woods salamanders were found more than 5,400 ft (1,645 m) from their breeding pond. Thus, a flat-woods salamander population has been defined as those salamanders using breeding sites within 2 mi (3 km) of each other, barring an impassable barrier such as a perennial stream. This salamander feeds on invertebrates.

Habitat

Optimum habitat for the flatwoods salamander is an open, mesic (moderate moisture) woodland of longleaf/slash pine flatwoods maintained by frequent fires. Pine flatwoods are typically flat, lowlying open woodlands that lie between the drier sandhill community upslope and wetlands down slope. An organic hardpan, 1-2 ft (0.3-0.6 m) into the soil profile, inhibits subsurface water penetration and results in moist soils with water often at or near the surface. Historically, longleaf pine generally dominated the flatwoods with slash pine restricted to the wetter areas. Wiregrasses, especially A. beyrichiana, are often the dominant grasses in the herbaceous (non-woody) ground cover. The ground cover supports a rich herbivorous invertebrate community that serves as a food source for the flat-woods salamander.

Adult and subadult flatwoods salamanders are fossorial (adapted for living underground). They enlarge crayfish burrows or build their own. Captive flatwoods salamanders have been observed digging burrows and resting at night with just the tip of their heads exposed. Preliminary data indicate that flatwoods salamander males first breed at one year of age and females at two years of age. There are no data on survivorship by age class for the species. The longevity record for their close relative, A. annulatum, is four years, 11 months; however, many Ambystomatidae live 10 years or longer. An adult female flatwoods salamander has been maintained in captivity for four years, four months.

Adult flatwoods salamanders move to their wet-land breeding sites during rainy weather, in association with cold fronts, from October to December. Breeding sites are isolated (not connected to any other water body) areas of pond cypress, blackgum, or slash pine dominated depressions which dry completely on a cyclical basis. They are generally shallow and relatively small, 3-4 acres (1.2-1.6 hectares) in area and 1-2 ft (0.3-0.6 m) in depth. These wetlands have a marsh-like appearance with sedges often growing throughout and wiregrasses, panic grasses, and other herbaceous species concentrated in the shallow water edges. Trees and shrubs grow both in and around the ponds. A relatively open canopy is necessary to maintain the herbaceous component, which serves as cover for flatwoods salamander larvae and their aquatic invertebrate prey. Ponds typically have a burrowing crayfish fauna and a diverse macroinvertebrate fauna, but lack large predatory fish, such as sunfish, bass, and bowfin.

Flatwoods salamanders need to maintain moist skin for respiration and osmoregulation (to control the amounts of water and salts in their bodies). Since they may disperse long distances from their breeding ponds to upland sites where they live as adults, desiccation (drying out) can be a limiting factor in their movements. Thus, it is important that areas connecting their wetland and terrestrial habitats are protected in order to provide cover and appropriate moisture regimes during their migration.

High quality habitat for the flatwoods salamander includes a number of isolated wetland breeding sites within a landscape of longleaf pine/slash pine flat-woods having an abundant herbaceous ground cover. Since temporary ponds are not likely permanent fixtures of the landscape due to succession, there will be inevitable extinctions of local populations. By maintaining a mosaic of ponds with varying hydrologies and by providing terrestrial habitats for use as colonization corridors, some protection against extinction can be achieved. A mosaic of ponds will ensure that appropriate breeding conditions will be achieved under different climatic regimes. Colonization corridors will allow movement of salamanders to new breeding sites or previously occupied ones.

Distribution

The historical range of the flatwoods salamander included parts of the States of Alabama, Florida, Georgia, and South Carolina that are in the lower Coastal Plain. It is possible that flatwoods salamanders once occurred in extreme southeastern Mississippi due to similarities in habitat to historical sites in adjacent Alabama. Surveys in 1995 did not report the occurrence of flatwoods salamanders in Mississippi.

The present distribution of the flatwoods salamander consists of isolated populations scattered across the remaining longleaf pine/slash pine flat-woods. Surveys indicate that the salamander survives in only 12% of its historical range.

Range-wide surveys of available habitat in Alabama, Florida, Georgia, and South Carolina have been ongoing since 1990 in an effort to locate new populations. More than 1,300 wetlands, which had a minimum of marginal suitability for the flatwoods salamander, were sampled, most of them multiple times. Of these, flatwoods salamanders were found at 110 sites (8% success rate).

In Alabama, there are five historical localities for the flatwoods salamander, all in the extreme southern portion of the State. Surveys conducted from 1992-1995 at the historical breeding ponds and from 1992-1998 at other potential breeding sites were unsuccessful at locating any flatwoods salamander populations. The salamander was last observed in Alabama in 1981.

In Georgia, 33 historical records in 19 counties have been reported for Georgia; however, flatwoods salamanders have not been relocated at any of these sites in recent years. Surveys over the last eight years of at least 478 wetlands with potential habitat for the flatwoods salamander have resulted in the location of 28 new breeding sites (6% success rate), comprising 11 populations. Most of these breeding sites occur on Fort Stewart Military Installation.

In South Carolina, there are 29 historical records for the flatwoods salamander. Despite annual surveys since 1990, flatwoods salamanders have been relocated at only three of these sites. One site is located on the Francis Marion National Forest and the other two are on private land. A new flatwoods salamander breeding site, representing a fourth population, was found in 1998 on the Francis Marion National Forest during state-wide surveys of approximately 118 wetlands considered to be potential habitat for this species.

In Florida, 39 of the 43 historical sites were relocated. Nine (23%) contained flatwoods salamanders. Additional survey work in 23 counties and at least 530 wetlands with potential habitat, resulted in the location of 81 new breeding sites (15% of total sites surveyed). Fifty-six (69%) of these new breeding sites occur in Liberty and Okaloosa counties. These sites were found due to extensive surveys of the Apalachicola National Forest and Eglin Air Force Base, both of which contain some of the best remaining pine flatwoods habitat in the Southeast. The total number of extant flatwoods salamander populations known to occur in Florida is 36 with 15 (42%) occurring on the Apalachicola National Forest and Eglin Air Force Base.

The combined State data from all survey work completed in the 1990s indicate that 51 populations of flatwoods salamanders are known from across the historical range. Most of these occur in Florida (36 populations or 71%).

Threats

The major threat to the flatwoods salamander is loss of both its longleaf pine/slash pine flatwoods terrestrial habitat and its isolated, seasonally ponded breeding habitat. The combined pine flat-woods (longleaf pine-wiregrass flatwoods and slash pine flatwoods) historical acreage was approximately 32 million acres (13 million hectares). Today, the combined flatwoods acreage has been reduced to 5.6 million (2.3 hectares) acres or approximately 18% of its original extent. These remaining pine flat-woods (non-plantation forests) are typically fragmented, degraded, second-growth forests.

Land use conversions, primarily urban development and conversion to agriculture and pine plantations, eliminated large acreages of pine flatwoods. Surveys of historical flatwoods salamander localities documented the destruction of nine sites from urban development or agriculture and loss of three additional sites due to their conversion to pine plantations. If present rates of loss continue, by 2025 nearly all natural pine flatwoods stands could be destroyed in Florida and Georgia.

Flatwoods salamander wetland breeding sites have also been degraded and destroyed. Alterations in hydrology, agricultural and urban development, silvicultural practices, dumping in or filling of ponds, conversion of wetlands to fish ponds, domestic animal grazing, and soil disturbance reduced the number and diversity of these small wetlands.

Forest management strategies commonly used on pine plantations contribute to degradation of flatwoods salamander forested and wetland habitat. These include soil-disturbing site preparation techniques, lowered fire frequencies and reductions in average area burned per fire event, high seedling stocking rates, and herbicide use, which may reduce plant diversity in the understory. The result of these strategies is a forest that approaches even-age structure, has a dense understory, and low herbaceous cover. Forestry practices that directly affect wetland breeding sites include ditching ponds or low areas to drain water from a site, converting second-growth pine forests to bedded pine plantations, harvesting cypress from the ponds, disposing of slash in wetlands during timber operations, using ponds as part of ditched fire breaks, using fertilizers near wetlands which can result in eutrophication (water enriched in nutrients), and disturbing the soil at a wetland.

Clear-cut harvesting of forested sites appears to be an additional threat. Amphibians, especially salamanders, are vulnerable to habitat drying and reduction of refugia because their moist permeable skin acts as a respiratory organ and must remain moist to function properly. Surveys show that salamanders are displaced from ponds in cut forests, and that there was lowered survivorship in individuals of the breeding population that immigrated to the breeding pond from the clear-cut.

Road construction plays a part in habitat degradation and destruction. At least one historical flat-woods breeding site has been filled in association with the construction of a road. Roads increase the accessibility of breeding ponds to off-road vehicle enthusiasts that use pond basins for "mud bogging," which disturbs the soil and vegetation and degrades the quality of a site for flatwoods salamander breeding. Roads may also alter the quality of isolated wetlands by draining, damming, or redirecting the water in a basin and contributing hydrocarbons and other chemical pollutants via runoff and sedimentation. Roads may also bisect corridors that the salamanders use for migration between ponds.

Exposure to increased predation from fish is a potential threat to the flatwoods salamander. When isolated, seasonally ponded breeding sites are often converted to more permanent wetlands inhabited by fish. Ponds may be modified specifically to serve as fish ponds or sites may be altered due to the construction of drainage ditches or firebreaks, which provide avenues for fish to enter the wetlands. Studies of other ambystomatid species have demonstrated a decline in larval survival in the presence of predatory fish. Fire ants may also pose a threat to the flatwoods salamander.

Habitat fragmentation of the longleaf pine ecosystem, resulting from habitat conversion, threatens the survival of the remaining flatwoods salamander populations Studies have shown that the loss of small fragmented populations is common, and re-colonization is critical for their regional survival. As patches of available habitat become separated beyond the dispersal range of a species, populations are more sensitive to genetic, demographic, and environmental variability and may be unable to recover. Roads contribute to habitat fragmentation by isolating blocks of remaining contiguous habitat. They may disrupt migration routes and dispersal of individuals to and from breeding sites.

Pesticides and herbicides may pose a threat to amphibians such as the flatwoods salamander, because their permeable eggs and skin readily absorb substances from the surrounding aquatic or terrestrial environment. In frogs, use of agricultural pesticides has resulted in lower survival rates, deformities, and lethal effects on tadpoles. Other negative effects of commonly used pesticides and herbicides on amphibians include delayed metamorphosis, paralysis, reduced growth rates, and mortality. Herbicides may also alter the density and species composition of vegetation surrounding a breeding site and reduce the number of potential sites for egg deposition, larval development, or shelter for migrating salamanders.

Long-lasting droughts or frequent floods may affect local flatwoods salamander populations. Although these are natural processes, other threats, such as habitat fragmentation and habitat degradation, may stress a population to the point that it cannot recover or re-colonize other sites.

Conservation and Recovery

The flatwoods salamander occurs on Federal lands administered by the Department of Defense, Fish and Wildlife Service, and U.S. Forest Service. These land management agencies are required to evaluate the potential adverse impacts to the flat-woods salamander from their activities. Federal activities that could affect the flatwoods salamander through destruction or modification of suitable habitat include forest management, military operations, and road construction.

Some populations on Federal lands have benefited where prescribed burning has been used as a regular management tool. However, multiple use priorities on public lands, such as timber production, and military and recreational use, make protection of the flatwoods salamander secondary. The National Environmental Policy Act requires an intensive environmental review of projects that may adversely affect a federally listed species.

At the State and local levels, regulatory mechanisms are also limited. The flatwoods salamander is listed as a rare protected species in Georgia. This designation protects the species by prohibiting actions that cause direct mortality or the destruction of its habitat on lands owned by the State of Georgia and by preventing its sale, purchase, or possession. At present, there is only one known flatwoods salamander population on lands owned by the State of Georgia. In South Carolina, the flatwoods salamander is listed as endangered. Prohibitions extend only to the direct take of the flatwoods salamander. These regulations offer no protection against the most significant threat to the flatwoods salamander, which is loss of its habitat. The flatwoods salamander is considered rare in Florida, but there are no protective regulations for this species or its habitat in the State.

Fire is needed to maintain the natural pine flat-woods community. Ecologists consider fire suppression the primary reason for the degradation of remaining longleaf pine forest acreage. Pine flat-woods naturally burn every three to four years, probably most commonly in the summer months. Sampling of longleaf pine flatwoods sites in Florida indicated that less than 30% of sites on private lands received prescribed burning to mimic the effects of natural fire. The disruption of the natural fire cycle has resulted in an increase in slash pine on sites formerly dominated by longleaf pine, an increase in hardwood understory, and a decrease in herbaceous ground cover. Ponds surrounded by pine plantations and protected from the natural fire regime become unsuitable flatwoods salamander breeding sites, due to canopy closure and the resultant reduction in emergent herbaceous vegetation needed for egg deposition and larval development sites. Current forest management is moving away from burning as a management tool due to liability considerations and concerns that fire will damage the quality of the timber.

Contacts

U. S. Fish and Wildlife Service
Jackson Ecological Services Field Office
6578 Dogwood View Parkway, Suite A
Jackson, Mississippi 39213-7856
Telephone: (601) 965-4900
Fax: (601) 965-4340

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345
http://southeast.fws.gov/

Reference

U.S. Fish and Wildlife Service. 1 April 1999. "Final Rule To List the Flatwoods Salamander as a Threatened Species." Federal Register 64 (62): 15691-15704.