Wednesday, January 23, 2008

Cluck surprise

With this post we welcome Mr. Michael Hayslett of Sweet Briar College to the Mountain Naturalist blog. He started the "Vernal Pool Society of Virginia", whose website you can find here. This piece was originally written three years ago for his "Notes from the Field" column online.

The Society is dedicated to promoting conservation and research on vernal pool wetlands, a vital habitat for many threatened species. You can see Mr. Hayslett's work on the mole salamander (Ambystoma talpoideum) at this site.

--Seth Williamson


Funny how favorite things seem to find me, no matter where I roam. This bemusement was illustrated recently on a personal outing in which vernal pools were not expected to play a part. I spent several days at the beginning of the New Year camped in solitude atop House Mountain in Rockbridge County. I went up there alone to explore the summits, contemplate my ancestry, and to obtain some much needed renewal of mind, body, and spirit.

On my first full day, I took note of a remnant feature from bygone days when a pasture and orchard thrived in the saddle between the mountain's twin peaks. A round, concrete watering trough of 6X2 feet in size, bore the scrawled message on its rim, "JUNE 3, 1958 A.L.C." Setting at an elevation of 2,700 feet in a montane landscape, and being full of water I thought, "wonder if wood frogs could use this as an artificial breeding pool?"

I never gave it a second thought, until the following morning at 8:30, as I sat fuzzyheaded after a blustery night with little sleep. I thought I heard a hen turkey clucking out in the nearby gap, so I peered out the opening of the shelter and listened closely. Then I heard the distinctive double-note of a lone male Wood Frog, calling from that watering trough below me, that only yesterday was partly covered in ice!

This was certainly earlier in the season than anticipated to hear this sound. In fact, at that elevation, I wouldn't expect to hear this obligate amphibian for nearly another two months. But we had been experiencing an unseasonably warm spell of weather, and the temperature at 8:30 a.m. on the 4th of January, at 2,720 feet elevation in the western mountains of Virginia was only 52ºF! Of course, this was only one early, eager male and not a whole chorus.

I can only wonder if there is, in fact, a breeding population up there and where (if at all) there might be or had been a natural vernal pool in the area. Wood frogs are more mobile than mole salamanders, and they were more capable of monopolizing high-elevation springs and human-made features as alternative breeding sites, especially during the good ole' days of mountaineer homesteads.

Written from the field on 4 January 2005 by Mike Hayslett

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Postscript: It rained lightly on that same night (with air temperature about 50ºF) and I heard a (different?) wood frog male calling again at 10:00 p.m., this time up slope and not near the water source.

Author's Note: I have seen numerous instances of vernal pool amphibians migrating or breeding outside their expected seasons over the last five years (e.g., spotted salamanders immigrating in early autumn, marbled salamanders emigrating in late spring, etc.), as other researchers have, no doubt.

Many believe that these phenological anecdotes are evidence of global warming effects on local populations of amphibians. Consider also, that on the morning of 5 January, as I prepared to depart my mountain campsite, I found a soil-covered American Toad. She had just emerged from the leaf litter as a result of the warm rains and fog of the previous night!


Anonymous said...

Michael, enjoyed the story. I have heard frogs at various times these last two winters, when least expecting. As I stalk them though, they shut right up, so I have not made an id. Our elevation is over 2000 feet.
Question: When wood frogs and other amhpibians prematurly emmerge, are they taking mortal risk? Thanks, Scott

Seth Williamson said...

I don't know about all species, but wood frogs are apparently tough customers. This is from wikipedia: "Wood Frog is the common name given to Lithobates sylvaticus[1][2], previously Rana sylvatica. They are the only frogs found north of the Arctic Circle. In winter, as much as 35-45% of the frog's body may freeze, and turn to ice. Ice crystals form beneath the skin and become interspersed among the body's skeletal muscles. During the freeze the frog's breathing, blood flow, and heart beat cease. Freezing is made possible by specialized proteins, glucose and perhaps accumulation of urea, which prevent intracellular freezing and dehydration."

naturenut said...

So how did the contemplation of your ancestry go? And did you obtain your much needed renewal of mind, body, and spirit?