Flatwoods Salamander Headstarting

Subsisting primarily on a diet of earthworms and spiders, the silvery-gray reticulated flatwoods salamander (Ambystoma bishopi) and the frosted flatwoods salamander (A. cingulatum) inhabit the pine flatwoods-wiregrass ecosystems of the Florida panhandle. Both species of salamanders are long and slender, with a maximum length of about 5.2 inches (13 centimeters). They depend on isolated herbaceous ephemeral ponds situated within longleaf pine savannas and mesic flatwoods to complete their life cycles. Adults migrate from their upland retreats to breeding sites on rainy nights from October through December. Frosted flatwoods salamanders continue to experience precipitous declines and local extinctions despite being federally listed in 1999. The headstarting project is designed to increase population sizes of remaining frosted flatwoods salamanders to decrease their probability of extinction. The project also contributed over 450 salamander eggs to a captive assurance colony at the Amphibian Foundation (Atlanta, GA) where they also be used in captive breeding efforts.

The Apalachicola National Forest is one of two remaining population strongholds, but more than 60% of the populations on the forest have disappeared over the last 30 years. The few remaining populations are extremely small and are rapidly declining, placing the species at imminent risk of extinction. Unnatural fire patterns have allowed hardwood encroachment to occur within the shallow wetlands in which they breed, which has eliminated nesting areas, and rendered the wetlands ecologically unsuitable for the aquatic larvae. Wetland habitat restoration and improvements in prescribed fire management is underway, but biologists are afraid that populations may be too small to survive without additional intervention. Headstarting has been identified as a potential method to increase local population sizes until they can become self-sufficient.

Headstarting involves raising vulnerable life stages of a species to a stage where they are less vulnerable, and then releasing them back to the wild. To accomplish this, FWC biologists search for salamander eggs in thick vegetation within dry wetlands prior to them filling with winter rains. Once the ponds fill, young larvae are captured using bucket traps with "light baits." They are then raised in large plastic “cattle tank” mesocosms, where water levels are stable, and they are protected from predators. While in the mesocosms, larvae are monitored and fed on a regular basis. Feeding larvae involves cultivating zooplankton and collecting aquatic invertebrates from the wild. Once the larvae reach metamorphosis, they are released back to the breeding ponds where they were originally collected.

  • FWC biologist searches for flatwoods salamander eggs

    An FWC biologist searches for flatwoods salamander eggs.

  • close-up of frosted flatwoods salamander eggsA close-up of frosted flatwoods salamander eggs.

  • close-up of a single flatwoods salamander eggA close-up of a single flatwoods salamander egg.

  • large cattle tanks where eggs are hatched

    Flatwoods salamander eggs are raised in this mesocosm array. The eggs are hatched in these large cattle tanks where the aquatic larvae can be fed and protected from predators.

  • biologist inserting a PIT tag in a flatwoods salamander

    An FWC biologist inserting a PIT (passive integrated transponder) tag in a flatwoods salamander. PIT tagging is done under anesthesia and the salamanders are given 24 hours to recover before release.

  • two salamanders of different sizes

    Size disparity between metamorphic frosted flatwoods salamanders of similar age raised under identical circumstances. These individuals are recovering from anesthesia following tagging, measuring and tail-clipping for DNA.

  • hands holding multiple salamanders

    After three months, the larvae underwent metamorphosis and were released back to their breeding ponds. Nearly 400 salamanders were released, resulting in an 80% survival rate. The tagged salamanders will be monitored to see if these headstarted amphibians can successfully survive and reproduce in the wild.

A mark-recapture component allows researchers to track focal populations and determine if headstarting is effective in augmenting their population sizes. Two breeding ponds have been fitted with encircling drift fences in order to monitor the movement of salamanders during the breeding season.  Both headstarted and wild-captured salamanders are marked using visual implant elastomer or PIT-tags, which allows researchers to track their growth and survival over time. When conditions allow, researchers also conduct larval dip-netting surveys throughout the Apalachicola National Forest.

Research is conducted from October through May. This project began Oct. 3, 2016, and the ending date has not yet been determined. The researchers are at the end of year 3 of this project and anticipate needing at least five years to fully evaluate headstarting as a conservation technique. As of summer 2019, the project has headstarted over 1900 larvae resulting in the release of over 1700 headstarted metamorphs back to the wild. This represents a survival rate of 90%, which is estimated to be roughly 10 times higher than the survival rate for wild populations. This project will be finished once headstarting is determined to be effective or ineffective at recovering flatwoods salamander populations. Because flatwoods salamanders take 2-3 years to reach maturity, the researchers will need at least two more field seasons of headstarting and monitoring headstarted populations.  The U.S. Forest Service is a key partner in this project. Grants from the Cooperative Endangered Species Conservation Fund (Section 6), FWC's Aquatic Habitat Restoration and Enhancement Section, and the Fish & Wildlife Foundation of Florida's Conserve Wildlife Tag program were instrumental in funding for this project. If successful, larval headstarting could be applied to flatwoods salamander populations in other areas.