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Ambystoma bishopi

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA AMPHIBIA CAUDATA AMBYSTOMATIDAE

Scientific Name: Ambystoma bishopi
Species Authority: (Goin, 1950)
Common Name(s):
English Reticulated Flatwoods Salamander
Synonym(s):
Linguaelapsus bishopi (Goin, 1950)
Taxonomic Notes: Based on patterns of genetic and morphological variation, Pauly et al. (2007) concluded that Ambystoma cingulatum should be split into two species, A. bishopi west of the Apalachicola-Flint rivers and A. cingulatum east of those rivers.

Assessment Information [top]

Red List Category & Criteria: Vulnerable A2c ver 3.1
Year Published: 2008
Date Assessed: 2008-01-01
Assessor(s): John Palis, Geoffrey Hammerson
Reviewer(s): Global Amphibian Assessment Coordinating Team (Simon Stuart, Janice Chanson and Neil Cox)
Justification:
Listed as Vulnerable because of a population decline, estimated to be more than 30% over the last three generations, inferred from habitat destruction and degradation. Additionally, population size may be less than 10,000 mature individuals, a continuing decline of at least 10% may occur within three generations, and no subpopulation may include as many as 1,000 mature individuals. However, adequate population information is lacking, so application of these criteria must await further data. Declines may be continuing, area of occupancy is small (perhaps less than 500 sq km), and the distribution may qualify as severely fragmented; under these criteria the species would qualify as Endangered.

Geographic Range [top]

Range Description: Range includes a small portion of the Coastal Plain of the southeastern United States from the Apalachicola and Flint rivers (western part of the Florida Panhandle and southwestern Georgia) westward (at least formerly) to extreme southwestern Alabama (Conant and Collins 1991, Pauly et al. 2007).

Based on 22 occurrences, and assuming 4 square kilometers per occurrence (actual value is unknown), area of occupancy would be 88 square kilometers; actual area of occupancy likely is larger than this.
Countries:
Native:
United States
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Surveys completed since 1990 indicate that 22 populations are known from across the historical range, with 2 in Georgia and the remainder in Florida (none known extant in Alabama) (USFWS 2005, Pauly et al. 2007).

Secretive habits of adults make population estimates difficult. Total adult population size presumably is at least 1,000, but actual number is unknown.

During extensive surveys of historical (pre-1990) breeding ponds, researchers recorded the species at only a small minority of formerly inhabited sites. Currently, the species presumably is declining in concert with continued loss of remaining intact pine flatwoods community (particularly degradation of groundcover). The rate of decline is unknown.
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: The following information pertains to the Ambystoma cingulatum/bishopi complex as a whole.

Post-larval individuals inhabit mesic longleaf pine (Pinus palustris)-wiregrass (Aristida stricta) flatwoods and savannas. The terrestrial habitat is best described as a topographically flat or slightly rolling wiregrass-dominated grassland having little to no midstory and an open overstory of widely scattered longleaf pine. Low-growing shrubs, such as saw palmetto (Serenoa repens), gallberry (Ilex glabra) and blueberries (Vaccinium spp.), co-exist with grasses and forbs in the groundcover. Groundcover plant diversity is usually very high. The underlying soil is typically poorly drained sand that becomes seasonally inundated.

Slash pine flatwoods is often cited as the preferred terrestrial habitat of the flatwoods salamander (e.g., Conant and Collins 1991). This may be the result of an error made by Martof (1968) in which he referred to longleaf pine as slash pine (Pinus elliottii). In addition, slash pine now dominates or co-occurs with longleaf pine in many pine flatwoods communities as a result of fire suppression and preferential harvest of longleaf pine (Avers and Bracy 1975). Historically, however, fire-tolerant longleaf pine dominated the flatwoods, whereas slash pine was confined principally to wetlands (Harper 1914, Avers and Bracy 1975). Post-larval individuals are fossorial (live underground) and occupy burrows (Goin 1950, Neill 1951, Mount 1975, Ashton 1992). Presumably, they remain underground during the lightning-season (May through September). Adults are rarely encountered under cover objects at or near breeding sites (J. Palis, pers. obs.).

Breeding occurs in acidic (pH 3.6-5.6 (Palis, unpubl. data)), tannin-stained ephemeral wetlands (swamps or graminoid-dominated depressions) that range in size from 0.02 to 9.5 ha, and are usually not more than 0.5 m deep (Palis, unpubl. data). The overstory is typically dominated by pond cypress (Taxodium ascendens), blackgum (Nyssa sylvatica var. biflora) and slash pine, but can also include red maple (Acer rubrum), sweetgum (Liquidambar styraciflua), sweetbay (Magnolia virginiana), and loblolly bay (Gordonia lasianthus). Canopy coverage ranges from near zero to almost 100% (Palis, unpubl. data). The midstory, which is often very dense, is most often composed of young of the aforementioned species, myrtle-leaved holly (Ilex myrtifolia), Chapman's St. John's-wort (Hypericum chapmanii), sandweed (Hypericum fasciculatum), titi (Cyrilla racemiflora), storax (Styrax americana), popash (Fraxinus caroliniana), sweet pepperbush (Clethra alnifolia), fetterbush (Lyonia lucida), vine-wicky (Pieris phillyreifolia), and bamboo-vine (Smilax laurifolia). Depending on closure of the canopy and midstory, the herbaceous groundcover of breeding sites can range from about 5% to nearly 100% (Palis, unpubl. data). The groundcover is dominated by graminaceous species, including beakrushes (Rhynchospora spp.), sedges (Carex spp.), panic grasses (Panicum spp.), bluestems (Andropogon spp.), jointtails (Manisurus spp.), three-awned grass (Aristida affinis), plumegrass (Erianthus giganteus), nutrush (Sclera baldwinii) and yellow-eyed grasses (Xyris spp.). The floor of breeding sites is riddled with the burrows of crayfish (genus Procambarus). Breeding sites are typically encircled by a wiregrass-dominated graminaceous ecotone. Breeding sites can include roadside ditches (Anderson and Williamson 1976; Palis, pers. obs.) and borrow pits (D. Stevenson, pers. comm.). Breeding sites often harbor fishes, the most typical species include pygmy sunfishes (Elassoma spp.), mosquitofish (Gambusia holbrookii), and banded sunfish (Enneacanthus obesus) (Palis, unpubl. data). Favorable breeding habitat lacks large predatory fishes.

Before breeding sites fill with water, eggs are deposited singly or in small groups on the ground beneath leaf litter, under logs and Sphagnum mats, at the base of grasses, shrubs or trees, or at the entrance to crayfish burrows (Anderson and Williamson 1976). In wetlands that fill incrementally, eggs are deposited amid graminaceous vegetation at the edge (J. Palis, pers. obs.). Egg deposition in shallow water also has been reported (Ashton 1992). Larvae hide amid inundated graminaceous vegetation by day, but will enter the water column at night (J. Palis, pers. obs.).
Systems: Terrestrial; Freshwater

Threats [top]

Major Threat(s): Potential threats include conversion of pine flatwoods habitat for agriculture, silviculture, or commercial/residential development; drainage or enlargement (with subsequent introduction of predatory fishes) of breeding ponds; habitat alteration resulting from suppression of fire; mortality and collecting losses associated with crayfish harvest; and highway mortality during migration.

The principal threat is habitat destruction as a result of agriculture, silviculture, and residential and commercial development. Modern silvicultural methods rely on altering soil hydrology, suppressing fire, shortening timber rotations, and replacing widely-spaced longleaf pine with dense plantations of slash pine. Loss of groundcover vegetation due to mechanical soil preparation, fire suppression, and shading by overstories of slash pine have been implicated in the decline in north Florida (Means et al. 1994, 1996).

Larvae are threatened in some wetlands by the harvest of crayfish as bait. Bait harvesters drag large hardware cloth buckets through inundated vegetation, dump the contents of the bucket on the ground, and then sort out the crayfish. Flatwoods salamander larvae taken in this manner are left to die or are collected as bait (J. Palis, pers. obs.).

The effect of herbicide or fertilization application on flatwoods salamanders is unknown. However, fertilization of plantations often results in eutrophication of wetlands, promoting algal blooms. Larval flatwoods salamanders have not been observed in algal-choked wetlands (J. Palis, pers. obs.).

Ditching or berming of small, isolated pond-cypress wetlands, a common practice when establishing slash pine plantations on mesic sites, results in lowered water levels and shortened hydroperiods (Marois and Ewel 1983). These hydrologic perturbations could prevent successful flatwoods salamander reproduction by preventing egg inundation or stranding larvae before they are capable of metamorphosis. Altered hydrology, in association with fire exclusion, results in a shift in dominance from pond-cypress to broad-leaved hardwoods that reduce herbaceous groundcover vegetation through shading (Marois and Ewel 1983). This may be detrimental since A. cingulatum larvae take shelter in herbaceous vegetation during the day.

Ephemeral pond-cypress depressions are sometimes converted into permanent water bodies, rendering them unsuitable for flatwoods salamander reproduction (J. Palis, pers. obs.).

A constant winter-burn fire plan could be detrimental (Ashton 1992).

See USFWS (1999) for additional information.

Conservation Actions [top]

Conservation Actions: This species occurs on Eglin Air Force Base in Florida.

Activities aimed at restoring/maintaining the ecological integrity of mesic longleaf pine-wiregrass flatwoods and associated ephemeral wetlands are needed to preserve extant populations of flatwoods salamanders.

Recovery is directly linked with the ability to preserve existing habitat and restore degraded habitat. Given the drastic decline in the extent of longleaf pine-dominated communities (Ware et al. 1993), elevation of flatwoods salamander populations above present levels is unlikely. Restoration of degraded mesic, seasonally inundated longleaf pine flatwoods and savannas has not been attempted, and may only be feasible in cases where soil disturbance is minimal. The effectiveness of reintroduction into areas where extirpated is unknown.

High quality occurrences include several wetlands within a matrix of pine flatwoods and savanna. Based on the maximum distance adults are known to travel between reproductive and nonreproductive habitat (1.7 km), each breeding site should be surrounded by at least 10 sq km of terrestrial habitat. Long term perpetuation of a viable population of flatwoods salamanders will presumably require protection of a larger area of terrestrial habitat encompassing a suite of alternative breeding sites (Travis 1994). A suite of wetlands guards against extirpation at any one breeding site, since animals can immigrate from nearby wetlands. The minimum viable population size needed to sustain a population longterm is not known. Preliminary drift fence data at Eglin Air Force Base, Florida, suggests that breeding population sizes are low relative to other Ambystoma (Palis, unpubl. data). However, this may be a site specific observation as larger breeding migrations have been observed elsewhere in the range (R. Moulis, pers. comm.). Presently, there is no method of assessing an occurrence based on the number of animals captured at a drift fence or the number of larvae inhabiting a breeding site.

Maintenance of intact mesic longleaf pine-wiregrass flatwoods and ephemeral wetlands by mimicking natural forces, such as lightning-season fire, is the most appropriate form of management. On sites where timber extraction is practiced, several precautions should be taken to limit the impact to flatwoods salamanders. Tree harvest should be restricted to dry periods to prevent soil compaction and rutting. Clearcutting should be replaced with selective timber harvest and natural regeneration enhanced by fire, particularly lightning-season fire. If off-site species such as slash pine have been planted, they should be removed and replaced with longleaf pine at densities found in nature. Mechanical preparation of the soil should be avoided. If a site supports mature, closed-canopy pine plantations, they should be thinned with as little disturbance to the soil and remaining groundcover as possible. The natural hydrology and fire regime of terrestrial and aquatic habitats should be restored on sites where altered.

The wetland/upland ecotone appears to be critical to successful flatwoods salamander reproduction. Some areas are in need of periodic burning to clear encroaching shrubby vegetation that shades out herbaceous ground cover (Palis and Jensen 1995). Maintenance of a graminaceous ecotone and breeding site will require burning in the lightning-season when wetlands are dry or nearly dry (Huffman and Blanchard 1990) . Bury et al. (1980) recommended that wiregrass not be burned in winter (destructive to wiregrass [used for egg attachment] and possibly to salamanders directly). Palis and Jensen (1995) stated that winter burns may be needed to avoid catastrophic fires when warm-season burning is initiated.

Mechanical disturbance of the wetland-upland ecotone should be avoided. The practice of "protecting" wetlands by encircling them with plow line should be abandoned. Where present, berms should be removed and drainage ditches filled.

Breeding ponds should not be dredged or stocked with fishes.

Demographic data are needed to better understand the natural history and, in particular, factors that limit population size (e.g., egg, larval, and metamorph survivorship; competition with other species).

Longterm drift-fence studies are needed at several nearby sites to examine inter-pond salamander movement and to delineate the range of natural population fluctuations.

More information is needed on the extent of upland habitat required to support a population breeding in a particular pond. Radiotelemetry or radioactive tagging of adults could be used to address this need.

Effects on salamander populations of different forms of resource management and of anthropogenic habitat disturbance need to be examined (Palis and Jensen 1995).

Citation: John Palis, Geoffrey Hammerson 2008. Ambystoma bishopi. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 01 November 2014.
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