Sunday, June 20, 2010

A Salamander Vanishing Before Our Eyes

As I stood along the edge of an isolated swamp deep in the heart of the Florida panhandle, I used my ears to listen for any calling frogs but my eyes were distracted as I watched a C-130 gunship lay waste to the ground below it as it flew in tight circles far above. Orange tracer rounds exploded out of the airplane and streaked to the ground like shooting stars. The gunners use these radiant rounds to help narrow in on their targets. Flashes of light from the airplane lit up the sky as the guns unloaded, it would take long seconds before the sounds of the blasts reached me, reminiscent of popcorn popping in the microwave.

Watching the military plane conducting its training exercises, it was surreal to consider the swamp in front of me was one of the few remaining wetlands where you had at least a chance of finding one of the rarest amphibian in the world, the reticulated flatwoods salamander, Ambystoma bishopi. I shivered in the cold April night and withdrew my arms into my short sleeved shirt as I tried to identify any male frog with love on their mind, singing their distinctive calls to attract mates. I was assisting on a research project attempting to determine key characteristics of flatwoods salamander breeding ponds, there are so few breeding wetlands left that it’s important to know them as well as we can. By identifying what other species share these habitats, it may be possible to identify potential flatwoods salamander breeding ponds without actually seeing the rare and secretive salamander’s themselves.

Like many species closely associated with the longleaf pine ecosystem, the flatwoods salamander requires open canopy forests and limited undergrowth to survive and persist. The key to keeping longleaf pine forests in this condition is allowing fires to burn through every two to three years. These fires reduce the amount of woody and brushy vegetation on the ground while allowing wiregrass, an indicator of a healthy longleaf pine forest, to thrive. Fires also discourage hardwood trees, such as turkey oaks, from becoming established. Keeping these oaks out keeps the canopy open, which increases the amount of sunlight reaching the ground (much to the delight of gopher tortoises, among other sun-loving species).

Oak trees have another, devious effect on flatwoods salamander breeding ponds. These wetlands are often so shallow they may even appear as just grassy depressions on the landscape. They’re so shallow they may completely dry up under the pressure from the intense summer sun (several large salamander species in the southeast breed during the winter and spend the rest of the year underground for this reason). When oak trees surround and even penetrate these shallow wetlands, their thirsty roots soak up much of the water. Over time, these unique wetlands may simply cease to exist. Resident salamanders are left to live out the rest of their lives without an opportunity to succesfuly breed, dooming the population to eventual extinction.

From South Carolina down through Georgia, the Florida panhandle and southwestern Alabama, many of the unique and isolated wetlands suitable for flatwoods salamanders have been converted to agricultural land and urban development, and fire was suppressed in many areas where they remained. As a result, the flatwoods salamander declined precipitously across its range, they’re even thought to have disappeared completely from Alabama.

In 2007, the already imperiled flatwoods salamander became even rarer due to an unlikely source. Geneticists, after examining flatwood salamanders from across their range, actually determined that what we previously thought of as one species were actually two separate animals!

Every individual has some unique genes; this is why no two people look exactly alike. Even identical twins have some differences. But, there are some genes that don’t change within a species, they are the same for every individual. Researchers use these genes to differentiate between species; if they are different, it’s evidence they’re not dealing with the same kind of animal. And that’s what they determined for the flatwoods salamander. Long ago, as the Apalachicola and Flint River system was formed, the once united salamander was divided into two groups. These groups were unable to cross the river, keeping them from interbreeding. Over time, this resulted in the salamanders diverging genetically, eventually to the point they could no longer be referred to as one species.

And just like that, this already rare salamander just became two even rarer salamanders! Populations of this salamander east of Apalachicola and Flint Rivers were named the Frosted Flatwoods Salamander, Ambystoma cingulatum, and populations west of these rivers were dubbed the Reticulated Flatwoods Salamander, Ambystoma bishopi.

Shivering, I recorded the cricket frogs and occasional leopard frog daring enough to reveal their presence in the frigid Florida night (yes, there is such a thing). It was about 1:00 o’clock in the morning by the time we finally finished surveying the required wetlands; cold and tired, I was ready to call it a night. But, as we were loading ourselves into the truck, the researcher I was assisting mentioned to me an exciting find he had come across the previous night. Alongside a wetland we had not visited, he had found a small flatwoods salamander residing under a log. This young salamander had just metamorphosed from its aquatic, tadpole-like stage, and was making its way onto land before dispersing across the landscape. During this time of year, it is sometimes possible to find flatwoods salamanders under logs and rocks, before they find deeper burrows and disappear until they are ready to breed.

A larval flatwoods salamander

Intrigued by the possibility of finding one of the rarest amphibians in the world for the first time ever, I agreed to extend the night a bit longer. After navigating through miles of sandy roads, we finally reached the pond, barely distinguishable as a wetland in the darkness of the forest. Rolling all the logs we could (and carefully replacing them after thoroughly examining the ground with our headlamps), it wasn’t long before a small and non-descript salamander was revealed under a large piece of bark. Drab and not particularly exciting to look at, it was hard to believe the little animal before me was one of the world’s rarest. The opportunity to see a flatwoods salamander with my own eyes was one I was sure to exploit, stories like this one may be all that’s left of the species for future generations.

Photos courtesy of Kelly Jones

Wednesday, June 16, 2010

Big Blue Returns to Alabama

       The year was 1954. Marilyn Monroe married Joe DiMaggio, Great Britain ended the food rationing program begun during World War II, and it was the last time a free-roaming and wild indigo snake was ever seen in Alabama. Indigo snakes once ranged throughout the southeastern United States from Georgia to Mississippi, crawling around clumps of wiregrass within longleaf pine forests, taking refuge within gopher tortoise burrows, and chowing down on just about anything they could fit into their mouths, including rattlesnakes. Today however, they’re thought to be gone from Mississippi and Alabama and restricted to isolated patches in Georgia and Florida.

       Over the last few decades, the once expansive and continuous longleaf pine forest has been decimated and fragmented due to conversion to agriculture (among other land uses) and road construction. Due to frequent lightning strikes, longleaf pine forests once burned about every three years; the trees and plants typical of this forest were adapted to this disturbance and thrived. When the forest became fragmented, burns were no longer able to sweep across the landscape and in some other areas, fire was actively suppressed by land managers. The end result was the invasion of hardwood and deciduous trees, changing the makeup of the pine forest and making it unsuitable for indigo snakes.

       Gopher tortoises, whose burrows often provide essential shelter for indigo snakes, were having their own problems. Harvested for food, run over by cars, and also suffering from habitat loss and degradation, populations of this stoic reptile crashed throughout their range. When they disappeared, so did the indigo snakes’ favorite hiding spot. Together with collection for the pet trade, habitat loss and road mortality conspired to make the indigo snake increasingly rare, protected in each state where it was known to occur and federally listed as a Threatened species.

       Conecuh National Forest in south-central Alabama has been experiencing an ambitious restoration effort for several years. Over time, the landscape has gradually transitioned back to a healthy longleaf pine forest, with numerous clusters of gopher tortoises enjoying the open canopy and abundant sunlight. It wasn’t long before some people started wondering whether it might just make sense to try to bring the indigo snake back to this vast and improved forest. Indigo snakes are important predators, eating rodents, snakes, and frogs. In turn, they provide food for large mammals and raptors. No natural area can be considered whole when it’s missing a species that plays such an important role; Conecuh could never return to its former glory until it again held all the species that once called it home.

       Perhaps most importantly, an indigo snake reintroduction would allow generations of Alabamians to experience a thrill that has been denied to them for years. When indigo snakes once again roam through the state, nature enthusiasts hiking through the woods would know they had a chance to come across a giant snake that could reach up to nine feet long! The thought is probably a terrible one for those who suffer from ophidiophobia (i.e. an irrational fear of snakes) but for those of us who appreciate magnificent beasts, the opportunity to spot an indigo snake is terribly exciting. The animals of the southeastern United States are part of our culture, when we lose a species such as the indigo snake, which is found nowhere else in the world, we lose part of our heritage.

       All of this was on my mind this morning as I met about thirty other people in an Andalusia parking lot and carpooled to a remote spot in Conecuh National Forest. We whispered to each other and pointed as we spotted two containers, each holding indigo snakes about to be released into the forest. The snakes released today were the offspring of Georgia animals, captured in 2008 and brought into captivity before they laid eggs. After laying, the adults were released back to Georgia although their eggs stayed behind. Held in incubators until they hatched, Auburn researchers monitored the eggs carefully and made sure the proper temperature and humidity levels were maintained. After hatching, the snakes were fattened up on a diet of fish, frogs and lizards to ensure they grew large enough to be inserted with a radio-transmitter. They also received PIT-tags, which are tiny microchips that give each snake a unique identification number. When a PIT tag is detected by a special handheld PIT-tag reader, it will give off a loud beep and the snake’s ID will pop up on the screen.

       Releasing snakes back into the wild isn’t as simple as dropping them off and hoping for the best. Some of the animals were to be held in huge pens bordered by hardware cloth fences. The thought is that if snakes are held in these pens for some time, they would be more likely to stay put when the fences were removed and they were free to wander at will. To test whether or not the fences are a benefit, some other snakes were released outside of the pens. By tracking the radio-transmitters inside the snakes, researchers will be able to determine survival rates of the two groups, and whether animals outside of the pens moved greater distances. For a wide-ranging snake like the indigo, frequent movements may expose them to perils such as roads and associated cars.

       Anticipation was in the air while the project’s partners, including Auburn University, the U.S. Fish and Wildlife Service, Alabama Department of Natural Resources, Alabama Natural Heritage Program, Zoo Atlanta, and Project Orianne discussed their role in the release. Finally, long-time indigo snake researcher and retired Auburn professor Dan Speake was granted the honor of releasing the first animal. Cameras clicked and flashed as an indigo snake was dropped into a pen and it disappeared into the undergrowth. Just like that, the indigo snake had returned to Conecuh National Forest and the state of Alabama.

       One might think that for a reintroduction effort such as this, success has been achieved when the snakes are released and they are crawling through the woods on their own volition. In truth though, it may be many more years before we will know what this huge project has achieved. Having a handful of snakes in Alabama is one thing, but it is essential these snakes eventually form a population capable of reproducing and sustaining itself. As Auburn professor Craig Guyer noted this morning, we won’t know whether all the hard work has paid off until a snake is captured in Conecuh and multiple scans with a PIT-tag reader fail to produce a single beep.

Indigo snake picture courtesy of Kelly Jones

6/18/10 update: The day after the snakes were released, those tasked with tracking the snakes via their radio-transmitters were confronted by a pleasant surprise. The first snake they found was in the process of devouring a copperhead! This gives us all hope these snakes will be able to find their way in the wilds of the Conecuh National Forest.