Hidden Dragons of the Pineywoods

This smiling dragon doesn’t breathe fire, fly around or torment humans. Rather, salamanders are unique amphibians that play a vital role in the ecosystems where they live.

Article and photos by MATT BUCKINGHAM

Far behind the pine curtain, where towering trees reach for the clouds, lies a hidden world. Nestled beneath the leaf litter in the shade of the forest floor, it is home to a cast of fantastic creatures that few will ever see.

Kings among them are the salamanders of the genus Ambystoma, commonly referred to as mole salamanders. Highly secretive, these hidden dragons spend as much as 95% of their time in burrows deep below the forest floor. For a few magical days each year, however, they emerge by the thousands to embark on a perilous journey and take part in an ancient ritual to ensure the continuation of their bloodlines.

A LITTLE HISTORY

When most think of Texas, lush forests and tall trees seldom come to mind. Yet by the late 1800s, East Texas was one of the largest timber producing regions in the nation. Over the

Five different and unique salamanders live in the East Texas Pineywoods. While their habitat preferences may vary, one common factor is vernal pools—isolated wetlands that form in upland depressions. Because these pools are seasonal, fish can’t survive, meaning a major predator isn’t present. following decades, hundreds of thousands of acres of virgin timber were felled to fuel a rapidly industrializing population.

Indeed, the Pineywoods of East Texas stand apart from a state primarily defined by sweeping prairies, desolate deserts, and rugged canyons. The Pineywoods are located at the eastern extent of the state, from the Louisiana border west roughly to the town of Crockett, where dense forests of pines and hardwoods give way to sprawling post oak savannas; and from Texarkana south to just north of Houston, where the land transitions to open prairies and marshes that reach to the Gulf of Mexico.

The term “Pineywoods” is a bit of a misnomer, as the forests here are quite diverse. While longleaf, shortleaf, and loblolly pines are important species throughout much of the region, hardwood forests also thrive. A variety of oaks, elms, maples, and hickories form pure hardwood stands or mingle with the pines.

Famously showy trees like dogwoods, redbuds, and hawthorns occur in the understory, while a variety of flowering forbs cover the ground and complete the scene for a landscape that looks more like an Appalachian forest than the rest of Texas. In fact, many are surprised to learn that East Texas has more in common, at least in terms of plant and animal species, with Virginia more than 1,000 miles to the east, than it does with Austin just 200 miles to the west.

The thriving forests are due in large part to the abundance of rainfall in the region. Annual average rainfall steadily increases as one moves from west to east across Texas. While areas like El Paso and Terlingua may receive less than 10 inches, the Pineywoods average between 40 to 60 inches per year.

The abundant rainfall is also what allows the salamanders to flourish. Though they may look like lizards at first glance, salamanders are amphibians, like frogs and toads. And as amphibians, they depend on water to complete their life cycles.

There are five members of the genus Ambystoma found in the Pineywoods. While some have different habitat preferences, the places they live have

one thing in common: the presence of vernal pools—isolated wetlands that form in upland depressions.

In the rich forests of the eastern U.S., these depressions can be found over pockets of dense clay scattered among a matrix of otherwise loamy soil. They may also occur in the scars of old stream beds left after some waterway changed millennia ago. These depressions begin to collect water in the late fall and early winter when abundant rainfall returns after a droughty late summer and early fall.

At the same time, trees and other plants are entering dormancy, when their water requirements are reduced dramatically. This reduction in plant activity results in a rising water table. By later spring and early summer, the water table begins to drop as thirsty roots once again draw from it. Rising temperatures increase evapotranspiration, and by late summer when the droughts return, these depressions will be dry once again.

Rich in biodiversity, vernal pools are home to a multitude of insects, copepods, and other invertebrates. These tiny organisms provide food for a diversity of amphibian larvae. Commonly known as tadpoles or pollywogs, these larvae are the early life stages of frogs, toads, and salamanders and they possess gills and tail fins, making them supremely adapted to life in the water.

Over time, they will develop legs, lungs, and other adaptations for life on land so that they can transition to a life outside the water by the time the pools dry up. The ephemeral nature of these wetlands means that fish are unable to survive. The absence of these voracious piscine predators is exactly what allows the amphibians to flourish.

Vernal pools are at their most vibrant in the late winter and early spring when salamanders and frogs migrate to them by the thousands to breed. It is an ancient ritual that is triggered by the first warm rains of the season, which typically occur sometime in mid-January in the Pineywoods. The joy of standing ankle deep in the frigid water of a vernal pool, watching hundreds of salamanders swimming across the leaf-laden bottom, and being serenaded by a cacophony of spring peepers, Cajun chorus frogs, and leopard frogs is an experience that every nature lover should experience at least once in their lives.

BIG MOUTH, BIG APPETITE

The genus Ambystoma contains some of the country’s most spectacular amphibians. The origin of the genus name is a bit of a mystery, however. In his book “The Amphibians of Great Smoky Mountains National Park,” Kenneth Dodd, Jr. suggests the name stems from the phrase “ana stoma buein” which translates “to cram into the mouth.”

Other authors have suggested that it comes from the Greek Ambyx or Ambykos and stoma meaning a “cup-like mouth.” It is also thought that the name comes from the Greek Amblys and stoma meaning “blunt mouth.” The latter seems most likely, as many historic authors wrote the genus as Amblystoma. It’s interesting to think that the genus spelled as we know it today may be a holdover from a misspelling in historic texts.

Regardless of the origin, it’s clear that the genus name hints at the large mouths and voracious appetites of these salamanders. Ambystoma salamanders are gape-limited predators, meaning they’ll eat anything they can fit into their mouths. Indeed, both the larvae and adults are known to gorge themselves on any type of prey available. Captive tiger salamanders, for example, may consume bits of hamburger meat and have even been recorded feeding on mice.

Each of the five Ambystoma species in East Texas leads a fascinating life. The descriptions below profile mysterious life histories of these hidden dragons of the Pineywoods.

THE SPOTTED SALAMANDER (AMBYSTOMA MACULATUM)

Large and brightly colored, spotted salamanders may reach up to 9 inches in length. Adorned with black skin interrupted by two rows of bright yellow spots, they are among the most spectacular of forest denizens. This species is considered by many to be the poster child for vernal pools.

East Texas Ambystoma salamanders are gape-limited predators, meaning they’ll eat anything they can fit into their mouths, which they can open wide. However, the smallmouth salamander is named for its proportionately smaller head and mouth.

As warm winter rains begin to fall, salamanders like this spotted salamander emerge and begin to migrate to vernal pools to breed.

While East Texas salamanders spend 95% of their time burrowed underground, they emerge once a year to lay eggs in vernal pools dotting the forest floor.

Their fate is so closely tied to the presence of these ephemeral wetlands that they are used as indicator species for healthy pools. And as healthy vernal pools depend on healthy forests, the spotted salamander, in turn, serves as an indicator for the health of the entire forest.

Spotted salamanders spend most of their lives confined to small burrows excavated by some species of rodent or other fossorial (burrowing) creature. As warm winter rains begin to saturate the soil, they slowly emerge from their underground haunts and migrate to their breeding ponds.

The males arrive first. Eventually they will outnumber the females several to one. After entering the water, they make their way to the perfect spot on the bottom of the pool where they will deposit their spermatophore, a gelatinous deposit containing their genetic material. They tend to revisit the same exact site year after year. Here they will stand guard over their deposit and await the females.

The arriving females are swollen with a gelatinous mass of unfertilized eggs. As soon as they see approaching females, the males begin to display near their spermatophore. They engage in a seemingly choreographed dance that involves a series of flips, gyrations, and underwater acrobatics.

Once a female appears receptive to his performance, a male will gently guide her over his spermatophore. She then picks it up and uses it to fertilize her eggs, which she deposits in a huge gelatinous mass on submerged twigs and vegetation.

The salamanders don’t dawdle in the ponds, and as quickly as they arrived, they vanish back into their upland burrows. There they will remain for the rest of the year, waiting for the next winter’s rain when the ritual will begin again.

One of the most fascinating aspects of the spotted salamander’s life history is a mutualistic relationship with a species of algae, Oophila amblystomatis. This single-celled algae only occurs within the eggs of the spotted salamander and is encountered nowhere else in nature. As the embryos mature, many egg masses will become green as these algae proliferate within them.

The developing embryos are oxygenated through the byproducts of the photosynthesizing algae, causing them to develop more quickly and suffer less mortality than embryos in egg masses where algae are absent. The algae benefit from the nitrogen-rich waste products and carbon dioxide produced by the embryos.

Tiger salamanders are the rarest of the Ambystoma salamanders of East Texas although they range across a vast swath of the nation.

THE EASTERN TIGER SALAMANDER (AMBYSTOMA TIGRINUM)

The rarest of the Pineywoods Ambystoma, tiger salamanders resemble spotted salamanders at first glance. They have a base color of black to olive, with numerous yellow, orange, or copper spots and blotches. Unlike the spotted salamander, whose spots generally form two parallel lines down their backs, the tiger salamander’s markings are randomly distributed over its back and sides. Tiger salamanders can also be differentiated by their stockier build and larger size, with some individuals reaching up to 12 inches in length.

In East Texas, tigers are restricted to bands of deep sand that were deposited during the Eocene Epoch, 30 to 50 million years ago. With names like Sparta, Carrizo, and Tonkawa, these deposits occur in narrow bands that roughly parallel the arc of the Gulf. Despite occurring more than 100 miles inland, these deposits provide evidence that the geology of East Texas developed as the Gulf slowly retreated to its current position.

Outside of East Texas, tiger salamanders are the widest ranging amphibians in North America. What was once considered a single species ranging from Arizona to New York is now considered by many to be two species. The western tiger salamander (Ambystoma mavortium) occupies the Great Plains and Rocky Mountains, and the eastern tiger salamander occurs in the forested eastern portion of the country. Both occur in Texas, with Central Texas apparently serving as the transition zone between species.

The range of tiger salamanders has been artificially expanded thanks to its popularity as fishing bait. Often sold in bait shops as “waterdogs,” their larvae are renowned for their ability to attract large bass. Inevitably, some of those will wiggle off the hook and escape. In other instances, the leftover waterdogs at the end of a fishing trip may be dumped into the water.

In some cases, bait store owners will deliberately introduce them into ponds on or near their property to encourage their breeding and keep a supply on hand. Inevitably, after morphing into adults, some will escape the confines of the property and spread to adjacent ponds.

Very little is known about eastern tiger salamanders in Texas, due largely to their scarcity and secretive nature. They apparently prefer oak-dominated savannas where they breed in vernal pools and permanent fishless clay-bottomed ponds surrounded by sandy uplands. They are considered a species of conservation concern in the state, and there is evidence that their populations may be declining.

THE MOLE SALAMANDER (AMBYSTOMA TALPOIDEUM)

With an oversized bulbous head and beady eyes, the mole salamander might be mistaken for a monster from a B horror movie, were it not for its tiny size. Averaging 3 to 4 inches in length, they are about half the size of a spotted salamander, and a third the size of a tiger salamander.

Their common name refers to their highly fossorial nature. Mole salamanders seem to spend less time on the surface than other Ambystoma salamanders in Texas, and it’s more difficult to predict when they might emerge to migrate to their breeding ponds.

Mole salamanders also spend more time in the water than other East Texas Ambystoma. In fact, mole salamanders have evolved a remarkable adaptation to allow them to take advantage of the relatively safe environment in the ponds of their birth; some adults are neotonic, a condition where larval characteristics are retained into adulthood.

While most Ambystoma salamanders will grow lungs, absorb their gills, and leave the ponds to live out their adult lives on land, some mole salamanders forgo this process in ponds where water remains year-round. They grow to adult size and can reproduce, all while keeping their gills and fin-like tails. If drought conditions cause their ponds to dry up, they can quickly absorb their gills, and morph into terrestrial adults where they will live out the rest of their lives on dry land, returning to their ponds only to breed.

When you think of salamanders, you think of a long, thin, lizard-like animal. The well-named mole salamander breaks that mold.

Compared with the other Ambystoma salamanders of the Pineywoods, mole salamanders appear rather drab at first glance. Generally grayish or brown overall, closer inspection reveals thousands of tiny purplish or bluish flecks, which are especially evident when they are in their breeding congresses. In East Texas they typically occur in longleaf or shortleaf pinedominated uplands.

THE SMALLMOUTH SALAMANDER (AMBYSTOMA TEXANUM)

Named for their proportionately smaller heads and mouths, smallmouth salamanders are relatively long and slender, and may reach up to 7 inches in length. This species has a wide range in eastern Texas, occurring from the Louisiana border west to Austin, and from the Oklahoma border south to Victoria. They are relatively uncommon in the Pineywoods, and are usually significantly outnumbered by other East Texas salamander species where they occur.

Elsewhere in the U.S. they can be found from Ohio west to eastern Nebraska and Kansas, and south to southern Mississippi. Coloration varies throughout their range, and it’s said that Texas is home to the most attractive representatives of the species. Here they are generally grayish, with dark bellies and numerous lichen-like white, light blue, or coppery blotches on their backs and sides.

Most salamanders may look like lizards, but they’re really amphibians, like frogs and toads.

Salamanders are an important indicator species in the East Texas Pineywoods. If the salamanders are thriving, so is the entire ecosystem.

Smallmouth salamanders are active on the surface longer than other Ambystoma and may be encountered from November through March if there is plentiful rainfall and mild temperatures. During this period, they spend most of their time hidden beneath logs and other debris on the forest floor. In East Texas, they tend to be found in or adjacent to bottomland hardwood and floodplain forests. Here they breed in shallow pools and may occasionally utilize holes left by uprooted trees.

THE MARBLED SALAMANDER (AMBYSTOMA OPACUM)

The species previously discussed breed during warm rains in late winter and early spring. Marbled salamanders, however, have adopted an entirely different strategy. They emerge from their subterranean haunts during the first cool rains of autumn, typically in early- to mid-October in the Pineywoods.

They migrate to the ponds of their birth, which are completely dry when they arrive. Here they court, breed, and lay eggs—all on dry land. The females deposit eggs singly into a tight cluster under woody debris in the pond’s basin. She will stay with them, guarding them closely until the winter rains fill the pool and the eggs disperse and hatch.

It’s a risky move. With no water in the pool, the marbled salamanders are gambling that the winter rains will come and the ponds will fill. If they don’t, the year’s crop of future marbled salamanders will fail. Fortunately, the eggs are adapted to avoid desiccation and can remain viable if the rains are late.

When the rains do come to flood the eggs, the payoff is huge. By being the first to hatch in the pond, the marbled salamander’s larvae are the top predators. By the time the spotted salamander eggs hatch, the marbled larvae may have already been growing for several weeks. In fact, it’s not unusual to see marbled salamander larvae resting on the egg masses of spotted salamanders, lying in wait for their hatching. And then they feast.

Trees aren’t the only part of East Texas forests to show off their colors. This marbled salamander has come out from its underground home to join others of its kind in an annual ritual of propagation. Vernal pools are at their most vibrant in the late winter and early spring when frogs and salamanders like these spotted salamanders migrate to them by the thousands to breed. It is an ancient ritual that is triggered by the first warm rains of the season, which typically occur sometime in mid-January in the Pineywoods.

ENVIRONMENTAL PREDICTORS

Amphibians are renowned as predictors of environmental health. Sensitive to changes in water quality and other environmental factors, they can serve as indicators to the quality of many of our ecosystems.

They have more direct benefits as well. Ambystoma salamanders are famous for their ability to regenerate limbs. Research into this may result in remarkable medical advancements.

Amphibian populations around the world are suffering steep declines. As with most of our biodiversity, the main threat is habitat loss. Protecting mature forests, implementing sustainable forestry practices, and adhering to regulations pertaining to wetland protection can help offset this threat.

Salamanders are also threatened by feral hogs and certain invasive aquatic plants, which may choke out the vernal pools they depend on. Land stewardship that targets these invaders is another good practice to ensure that these remarkable hidden dragons continue to thrive in the Pineywoods for generations to come.