Houston ChandlerViews:
Reticulated and Frosted Flatwoods Salamanders (Ambystoma bishopi, A. cingulatum) are two of the rarest salamanders in the United States, having experienced severe population declines and range contractions. These declines have occurred even within protected landscapes and have left both species sitting on the edge of extinction. Like most longleaf pine specialists, flatwoods salamander populations have been impacted by both the near total loss of longleaf pine systems (less than 3% remain) and the widespread fire suppression that occurred during the 20th century.
Flatwoods salamanders breed in temporary wetlands embedded within longleaf pine flatwoods and depend on habitats with open canopies and thick herbaceous vegetation (grasses and forbs) for multiple aspects of their reproductive cycle (Gorman et al. 2009; Jones et al. 2012; Gorman et al. 2014). Fire suppression in breeding wetlands leads to an encroachment of woody vegetation, shading out herbaceous vegetation and making wetlands unsuitable for salamander reproduction. Even as prescribed fire became a widely applied management tool, issues remained with fire seasonality because winter fires rarely burn through breeding wetlands that typically hold water during this time of year (Bishop and Haas 2005). Furthermore, even under the best fire conditions, it can be exceedingly difficult (and require many fires) to remove a build-up of shrubs and woody vegetation from wetland basins. Thus, restoring breeding habitat for flatwoods salamanders is a challenging management problem with no easy solutions.
By the mid-2000s, it was clear that new techniques were needed to improve flatwoods salamander breeding habitat within a timeframe that would be meaningful to ongoing conservation efforts. Populations were still declining and wetlands with suitable habitat were becoming slowly isolated from one another even within landscapes that saw regular prescribed fire. Research published by Gorman et al. (2013) examined the utility of using a combination of mechanical (i.e., manual removal with chainsaws) and herbicide treatments to improve wetland conditions in pine flatwoods on Eglin Air Force Base. The results of this early work offered a promising glimpse of what could be possible in these wetland systems (i.e., a clear and rapid reduction in canopy cover), although there were other challenges to address. Examples include: 1) Herbaceous vegetation is often slow to respond to canopy removal alone because thick duff layers accumulate in wetlands without regular fires to remove this organic material. 2) The manual work required to remove woody vegetation is, for lack of a better way to describe it, brutal, commonly taking place during the Florida summer when wetlands are dry. This has caused more than one crew to throw in the towel over the years. 3) A somewhat obvious, but perhaps overlooked issue, is what to do with the huge amounts of woody biomass as it is manually removed from wetlands. Several solutions to this problem have been examined, ranging from burning to grinding up the material, but all seem to leave something to be desired. These are the types of challenges that come with trying new adaptive management approaches and each had to be addressed if the technique was going to succeed on a large scale.
Today, mechanical removal of woody vegetation from known and potential flatwoods salamander breeding wetlands is being applied at a large scale on Eglin Air Force Base and some surrounding properties. The results over the last few years have been nothing short of incredible, turning completely overgrown, fire suppressed wetlands into open-canopied systems with abundant herbaceous vegetation. A key step in the success of these efforts has been buy-in and partnerships with the fire division on Eglin Air Force Base. Wetland basins are now frequently targeted for burns, often after the surrounding areas have been burned earlier in the year. These basin burns are an important step to removing the buildup of organic materials and promoting the return of herbaceous vegetation.
Over the next few years, these restoration efforts will focus on restoring wetlands in clusters surrounding occupied sites. The goal is to allow flatwoods salamander populations to interact and disperse through natural processes, increasing their resilience to other potential threats. Survey work has already revealed promising results of these habitat improvements as salamanders were detected in two historically occupied wetlands that had remained unoccupied for many years. It is unknown whether they colonized these wetlands from other sites or were always there in small numbers that have since increased because of the improved habitat. Regardless, it is a promising sign that all the effort that has gone into improving flatwoods salamander breeding habitat on Eglin Air Force Base will have a tangible effect on the remaining populations.
As I hinted at above, this type of large-scale habitat work is labor intensive and requires a diverse group of partners to make it successful (too many to name here). The work would not be possible without the support of the natural resources personnel on Eglin Air Force Base and from both U.S. Fish and Wildlife Service and Florida Fish and Wildlife Conservation Commission. Both flatwoods salamander species still sit on the edge of extinction, with the effects of climate change already being felt, but if it is possible to recover these species, the hard work of this dedicated group will be the primary reason.
Literature Cited
Bishop, D. C., and C. A. Haas. 2005. Burning trends and potential negative impacts on flatwoods salamanders. Natural Areas Journal 25:290–294.
Gorman, T. A., C. A. Haas, and D. C. Bishop. 2009. Factors related to occupancy of breeding wetlands by flatwoods salamander larvae. Wetlands 29:323–329.
Gorman, T. A., C. A. Haas, and J. G. Himes. 2013. Evaluating methods to restore amphibian habitat in fire-suppressed pine flatwoods wetlands. Fire Ecology 9:96–109.
Gorman, T. A., S. D. Powell, K. C. Jones, and C. A. Haas. 2014. Microhabitat characteristics of egg deposition sites used by reticulated flatwoods salamanders. Herpetological Conservation and Biology 9:543–550.
Jones, K. C., P. Hill, T. A. Gorman, and C. A. Haas. 2012. Climbing behavior of flatwoods salamanders (Ambystoma bishopi/A. cingulatum). Southeastern Naturalist 11:537–542.
