Spring Salamander Gauntlet: Avoiding Raccoons, Sexual Parasitism, and Suburban Sprawl

2016-03-31T10:11:42+00:00 March 31st, 2016|

 

By Matt Stansberry, Illustrations by David Wilson

It was the kind of morning I would never spend outside: 46 degrees Fahrenheit, rain running down the bare trees and pooling up on the muddy ground.

Nothing looked alive. So much that happens in the early spring seems to emerge from the earth unnoticed.

In a woodlot thirty miles east of Cleveland, Geauga Park District naturalist Tami Gingrich and I clambered over the rain-drenched rocks outside of the district’s offices at Big Creek Park, around the back of the facility to manmade pools.

Gingrich handed me a piece of rope and I hauled in the first of several wire mesh minnow traps she had left in the water the night before. The traps were full of writhing salamanders. We opened each net, and poured hundreds of squirming amphibians into a plastic bin.

Gingrich knew these warm, wet nights would mark the beginning of the annual amphibian migration and breeding season.

Of all of the amphibians in our region, the Jefferson Salamanders are the first to emerge. Gingrich had started finding them as early February 2, a possible county record during this mild winter.

At the first signs of thaw, Jefferson Salamanders creep out of their hiding places and flock toward temporary woodland pools, traveling up to half a mile and even crossing snow and ice.

Jeffersons belong to the mole salamander family, and some species in this group such as the Eastern Tiger Salamander can grow to a foot long. Mole salamanders are stocky, built for digging tunnels. They spend nearly their entire lives underground in animal burrows. Early spring is the only opportunity of the year to see them, as they will soon disappear back into their subterranean lairs in the woods.

WSalamander“I get calls after warm rainy nights, people in new developments saying huge salamanders are walking around the base of their house, looking in their window wells,” Gingrich said. “The salamanders return to the vernal pool where they were born each year to breed, and the new home was built on their breeding site.”

Gingrich said these salamanders can live to be quite old. I imagined those people in their new houses, startled into regret each spring as the big dark eyes of mole salamanders stare into their basement windows year after year.

The biological term for returning to where were you were born to breed is philopatry, and the behavior occurs all over the animal kingdom, from birds, to amphibians and fish.

In the case of these salamanders, Gingrich had spent several years transplanting Jefferson Salamander eggs to manmade vernal pools near the administrative building, and now they returned each spring.

One reason for philopatry might be the very specific, narrow requirements for breeding success. Vernal pools where the salamanders and other amphibians breed are complex, fragile habitats. In northeast Ohio the vernal pools might have been created by something as dramatic as a gouging by the Wisconsinan glacier, or mundane as a big tree tipping over and a pool forming in the hole where the root wad had once been. Typically these small concave depressions are lined with clay or some other impermeable substrate and hold surface water for most of the year, drying up in late summer. It is this impermanence that suits the amphibians – as larger permanent bodies of water would support fish, which would wipe out the larvae.

[blocktext align=”right”]They don’t look like much, but even small pools can support hundreds of individual animals over the course of a spring.[/blocktext]The window to see these animals is so short, if you miss the breeding season, it’s like they were never there.

As a boy growing up in a rural township east of Akron, I spent a lot of time in a low, wet spot in the woods behind my house. I called this depression “the swamp” and often slipped into the black muck up to my knees in my school clothes, driving my parents crazy.

This was my favorite place, and it formed the landscape of my imagination. It was also the kind of place homeowners and developers would prefer to fill-in and destroy.

These pools look like a breeding ground for mosquitos, and that would seem to be reason enough to get rid of them.

It would be easy for someone not paying attention to amphibian life cycles to miss the importance of a wet spot in the woods, to fail to connect these places to the sounds of frogs in the spring and the large salamanders silently living under the upland woods nearby.

The window to see these animals is so short, if you miss the breeding season, it’s like they were never there.

* * *

Gingrich and I hauled the plastic bin of salamanders into the building to get a closer look at them. When she’d placed traps in the pool on a warm night two weeks prior, all of the captives had been male Jefferson Salamanders. This time the haul was primarily female Jefferson females and some of the first male Spotted Salamanders. Typically, the males of a given species arrive first and the females follow.

The Jefferson Salamanders are slate colored, with light bluish flecks along their flanks. The have liquid black eyes, and a friendly looking face. The Spotted Salamanders were a similar grayish color, with vivid yellow spots. They are plump, almost lewdly ribbed. The colors are stunning.

Ambystoma_jeffersonianumYou’re not really supposed to touch them. Their skin is absorbent and sensitive to contaminants and oils. But the prospect of laying hands on hundreds of salamanders was too much to resist. Gingrich correctly guessed that I don’t wear a lot of cologne or lotions, and so I was allowed to wet my hands and pick up the salamanders like an overgrown five-year old kid.

Gingrich and I talked about their lives, while I let salamanders walk over my hands.

We talked about what it must be like living underground the woods eating worms, insects or whatever else you might fit in your mouth. “Anything you find when you roll over a log is something they might feed on,” Gingrich said.

We talked about the odyssey these animals make when they crawl out of a burrow into the dappled moonlight and need to avoid owls, raccoons, skunks, and cars.

“I notice more raccoons dead on the road after a migration because they get hit by cars picking up the salamanders that get run over,” she said.

And of course, we talked about their sex lives. Once in the pool, the males “Do a little dance with the female, whirling around each other, and when he gets her attention, he deposits a spermatophore,” Gingrich explained. “It looks like a little golf ball on a tee, and she straddles it. The males place them nearby and say ‘Hey, help yourself.”’

Donald Culross Peattie writes of “The terrible continuity and fluidity of protoplasm, the irrepressible forces of reproduction – not mystical human love, but the cold batrachian jelly by which we vertebrates are linked to the things that creep and writhe and are blind yet breed and have being.”

Terrible fluid continuity. Help yourself. Ah, the romance.

[blocktext align=”right”]I was allowed to wet my hands and pick up the salamanders like an overgrown five-year old kid.[/blocktext]Despite the seeming lack of amorousness, male Jefferson Salamanders need to be picky about which females they mate with.

Dr. Tim Matson, Curator of Vertebrate Zoology at the Cleveland Museum of Natural History explained that hybrid female salamanders can function as sexual parasites, eventually wiping out an entire population.

Closely related mole salamander species like Jefferson, Blue-spotted, Small-mouth  and in some cases the Tiger Salamander will hybridize. The salamanders can have two or three or even five sets of chromosomes.

The genetics get complicated fast, but basically triploid (containing three sets of chromosomes instead of two) salamanders and further hybridized individuals are labeled unisexuals. These unisexuals are all female, and might look a lot like a normal Jefferson Salamander. In fact, without lab equipment, they’re functionally impossible to tell apart.

Very often, hybrids are sterile. But according to Matson, these unisexual or hybridized specimens can lay eggs, and produce only females.

“I did a ten year study in Lake County and studied diploid Jefferson Salamanders and unisexual hybrids,” Matson said. “At the beginning of the study, we had an equal number of diploid and triploid specimens. At the end of ten years, we had only two males, all the rest were unisexual females.

“The diploids lose out ultimately, if the polyploids don’t produce males, and the number of males goes down, the whole population crashes. The Jefferson salamander population had bottomed out and had almost gone to zero. The hybrids don’t produce males and they compete with diploid females for sperm. If no males migrate to the area, they hybrid females can drive local populations toward extirpation in the long run.”

* * *

From early February through late March, Jefferson Salamanders will lay eggs in their vernal pools.

Without leaves on the trees, sunlight will quickly warm the pools and cause algae to grow on the eggs. This algae provides additional oxygen for the developing larvae and elevates the growth rate.

According to Matson, the algae’s oxygen boost may allow the salamander larvae to attain a larger size and undergo metamorphosis a little sooner, which in dry years may mean the difference between survival and dying in a dried up pool.

It strains my agnosticism to imagine how all of these disparate, delicate functions come together to support these animals – the clay-lined depressions in the ground allowing just the right amount of water to persist, the spring sun shining through the leafless forest canopy, an algae the supplementing the larvae’s growth.

The eggs hatch in about thirty days and the larvae feed on microinvertebrates – tiny ostracods, crustaceans, and insects. When they get bigger, they’ll eat anything they think they can fit in their mouths, including each other. The strongest remaining individuals will emerge from the water around August.

They will need to learn to find or dig a burrow, to hunt on land, and to stay below the frost line as winter sets in. Three years later, they’ll emerge from underground as sexually mature adults and make their way back to the spring pools where they were hatched.

WbeltsalamanderJefferson Salamanders are not an endangered or threatened species in Ohio, but it is hard to know the true nature of the population given the recent research on of how the hybrid or unisexual individuals impact the species.

The larvae are highly sensitive to toxins like copper, zinc and salt. They’re also susceptible to chytrid fungus, an invasive pathogen killing amphibians across our region and globally. They are an early indicator of problems in an ecosystem.

On one of the first warm, wet nights of spring, I held two of my sons’ hands as we crept down the wet dark road leading through Cleveland Metroparks Brecksville Reservation. We wore headlamps and walked slowly with a loose group of other guests who wanted to see salamanders in the wild. The park service closed Valley Parkway to protect the migrating amphibians from cars, and so we walked the pavement with our eyes scanning the ground.

[blocktext align=”right”]We found brightly
colored living things emerging and disappearing into the still-winter woods, before anyone might notice.[/blocktext]My oldest son is seven years old and has the best night vision. He spotted the first one right away, what appeared to be a Jefferson Salamander crossing the yellow painted lines of the middle of the road. We surrounded the salamander in the light of our headlamps.

I explained to the boys that this was likely a female, on her way to mate and lay eggs in the woods. We walked further into the gloom, listening to the Spring Peepers calling from both sides of the road. We found Wood Frogs and Spotted Salamanders.

We spent the night with these animals before they would disappear again, and participated briefly in their march toward the vernal pools. We found brightly colored living things emerging and disappearing into the still-winter woods, before anyone might notice.

___
Matt Stansberry was born in Akron, Ohio. He is a dad, nature writer, and fly fisherman. Find him on Twitter @LakeErieFlyFish. More of David Wilson’s illustration work can be found at dwillustration.com.

Matt and David’s monthly column, “North Coast Biodiversity,” is collected here. Order copies of the first edition of Redhorse — a print collection of the first six “North Coast Biodiversity” columns — here, and signed prints of David Wilson’s original art for the column here.

Find out more about Matt & David’s publications/additional projects on the newly launched Redhorse site: http://redhorsemag.com.

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