VA Press: Sweet Briar students take salamander census

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NEWS & ADVANCE (Lynchburg, Virginia) 05 March 08 Sweet Briar students take salamander census (Dave Thompson)
They only come out in the dark. Warm, rainy nights are a must. And the event only happens once a year as spring approaches.
Tuesday night’s temperature and weather proved just the right combination for Sweet Briar College’s Spotted Salamander population to do their thing.
Herpetologist Michael Hayslett, the college’s naturalist-in-residence, was on hand to help with the second annual study of the animals’ yearly mating migration.
“Every year, if I don’t take in at least one big night event, I feel like I missed out,” Hayslett said.
A type of mole salamander, so named because the majority of its life is spent underground, the spotted salamander can be found throughout most of the continent. But it’s a rare sight due to its preferred subterranean dwelling.
“Unless you’re in the right place at the right time,” Hayslett said, “you would probably never see this thing.”
Tuesday night, just after dark, the place was the small wooded area around Guion Pond, at the college.
Professor Linda Fink, who teaches biology and ecology courses at the college, explained the reason for the study.
“We wanted to know how big are they, how old are they, how many are there,” she said, “and what we found is there’s a huge population compared to what we were expecting.”
The salamander census included marking the salamanders based on their area of the woods, denoted by separate containers.
Each was measured, weighed and injected with a visible injectable elastomer, a compound that produced a fluorescent mark just underneath the skin.
“It lasts, supposedly, their whole life,” said Sara Rothamel, Fink’s teaching assistant, who coordinated the study from the students’ side.
Rothamel said the salamanders were tagged based on the area they came from.
“That way, next year we can see where they came from and if they’re interbreeding,” she said.
Hayslett said the population, which Tuesday night’s numbers listed at 636, was denser than the small wooded area would normally have.
And last year, problems with the capturing system led to estimates about 80 salamanders fewer.
“This year we thought we were much more organized,” Fink said early Tuesday night. “We’ve got two classes of students, we have extra professors here and we’re already overwhelmed by salamanders.”
Most of the male salamanders, which deposited spermatophores containing egg fertilizer in the pond, left the water that night. Hayslett said the females internalized the fertilizer, and would lay their eggs within the next few days.
The rest of the males, along with the females which have yet to lay their eggs, need to wait until the next rainfall to leave the pond.
http://www.newsadvance.com/servlet/...icArticle&c=MGArticle&cid=1173354865124&path=

 

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VA Press: Salamanders Make Pond Pilgrimage

SWEET BRIAR COLLEGE (Virginia) 07 March 08 Salamanders Make Pond Pilgrimage (Suzanne Ramsey)
Well, it’s happened again and almost like clockwork, too. On March 4, only a couple of days later than last year’s event, Sweet Briar’s population of spotted salamanders made its annual migration to Guion Pond.
The 8-inch long, yellow polka dotted amphibians — commonly described as “cute” — travel to the pond each year to breed. As biology professor Linda Fink has said, “Once a year, they doodle over to the pond, have sex for a week and come back.”
Students and faculty counted, weighed and marked more than 600 salamanders this year.For the other 360-some days of the year, the salamanders live in the woods behind Guion Science Center, eating earthworms and bugs. On the first warm, rainy day of the year — the “salamander rain” — they emerge from their burrows and make their way to the pond.
The males arrive first and deposit spermatafores on the bottom of the pond. When the females arrive, they “internalize” them, Hayslett explained, by picking them up with their sex organs, called “cloacae.” After fertilization, the females lay their eggs and leave the pond with the next rain.
“Salamander sex is kind of bizarre,” Hayslett said. “There’s no contact between the male and the female and yet there’s internal fertilization. It’s kind of different.”
Conditions were right for the mass exodus on March 4, with the weatherman predicting a 60-degree day with torrential rain, thunder and even a tornado watch.
According to SBC naturalist-in-residence Mike Hayslett, the thunder may act as an alarm clock for the little creatures. “Some say it’s an auditory clue,” he said before last year’s event. “The rumbles and vibrations might be a cue to wake them up.”
Environmental studies major Sidney Bieser ‘10 weighs a salamander.For the second year in a row, Sweet Briar students, most of them in the ecology and field natural history classes, documented the migration. Before the night was over, they had captured, weighed and marked 636 salamanders — an increase of nearly 80 over last year’s total.
Hayslett attributed the difference to knowing the slippery creatures a little better. In 2007, spotters were scattered throughout Guion Woods to capture the critters, but halfway through the evening, scads of salamanders were found emerging from an unmonitored creek bed adjacent to the dam.
“Last year, they came out of the dam and we missed a lot,” he said.
This year, students were assigned to the area and found salamanders erupting from the creek bed like a “Texas tea.” Hayslett, standing on top of the dam with a net, predicted the final total would “knock our socks off.”
Another change in the operation involved the way the salamanders were marked for future studies. In 2007, the “Twitty” method was used, which involves clipping one of the salamander’s toes.
This year, a visible injected elastomer that fluoresces in ultraviolet light was used. Ecology teaching assistant Sara Rothamel ’09 called the method “more reliable,” and said using the VIE eliminates the question of whether a toe was removed or lost accidentally and it lasts the lifespan of the animal.
Students also counted, weighed and marked the salamanders in tents set up around the pond rather than carry them in buckets to the biology lab in Guion. This move sped up processing and, according to Hayslett, “reduces the stress and interferes less with [the salamanders’] progress.”
Sweet Briar’s dean Jonathan Green was one of several faculty members who showed up during the event, either to lend a hand or observe. “I came down here to see my students being students,” he said. “The salamanders are cool, too. Twenty-year-old scientists being scientists. It’s especially cool when they can tell me something about them.”
http://www.sbc.edu/news/?id=2480