To the FWGNA group:
I was born and raised in Waynesboro, Virginia, where the Chamber of
Commerce likes to advertise that “The Skyline Drive meets the Blue
Ridge Parkway.” The Skyline
Drive runs 105 miles north from Waynesboro through the Shenandoah
National Park to Front Royal, generally at 1-2,000 ft. elevation.
South from Waynesboro the Blue
Ridge Parkway extends another 412 miles through the mountains to
Asheville, North Carolina, at elevations rising to 6,000 feet.
I spent many a lazy summer day in my youth picnicking with family on
the SKD and the BRP, and not a few warm evenings at the overlooks with
my girlfriend. One of my favorite spots was the visitor center at
Humpback Rocks (BRP mile 5.8), where latter-day pioneers live in an
authentic log cabin and farm the rocky hillside (Fig. 1).
The tiny, hand-hewn springhouse on that property must have stood
unchanged for 200 years (Fig. 2).
No surface water enters or leaves the springhouse at BRP mile
5.8. Water seeps up through the rocks, travels in complete
darkness for about 3 feet, then seeps back into the earth and
disappears. (A narrow PVC pipe has been installed to keep the
path from becoming muddy.) But if you crawl through the door,
grab a wet rock, pull it out into the sunlight and turn it over, you
may be lucky enough to discover a scattering of tiny white hydrobiids, Fontigens orolibas (Hubricht), the
spring snail of the Blue Ridge.
My attention was first called to this remarkable animal by the
wonderful 1990 monograph of Hershler, Holsinger, and Hubricht, “A
revision of the North American freshwater snail genus Fontigens” (Smithsonian Contrib.
Zool. 509). To tell you the truth, I don’t know which is more
amazing – the fieldwork of Leslie Hubricht, the scholarship of Bob
Hershler, or the biology of the snails they have teamed up to
document. The authors reviewed nine Fontigens species in their work,
including four species from the Commonwealth of Virginia, meticulously
documenting hundreds of remote and scattered populations.
So one fine morning not too long ago I set off up the Skyline Drive in
my pickup truck, HH&H monograph in my lap and topo maps on the seat
beside me, determined to visit as many populations of F. orolibas as I could before the
sun went down. The habitats I sampled ranged from proper springs
with good water flow down to wet seeps in grassy or marshy high meadows
many miles from the nearest permanent water. Figure 3
shows a typical spring, at a visitor cabin operated by the National
Park Service down the mountain below SKD mile 81. I found snails
only on the underside of rocks very near such springheads, never in any
abundance.
The animals themselves are typically no more than a couple millimeters
long and essentially colorless. Figure 4
shows a 2.9 mm F. orolibas
(below) crawling with an individual F.
nickliniana, a widespread species found throughout the eastern
U.S. in valley springs and spring runs. Fontigens nickliniana does not
share the retiring habit of F.
orolibas, and seems unafraid to crawl about quite brazenly on
the open streambed. The body color difference is striking.
I was ultimately able to visit seven of the sites listed by HH&H as
habitats for Fontigens orolibas
– a pretty full day, but only 20% of the total sites they
recorded. And I’m pleased to report successful collections of F. orolibas from five of
them. The other two sites had been capped and the water
diverted. But given the ephemeral nature of natural snail
populations and their habitats, I think the confirmation of 5/7ths of
any list of historical freshwater snail records is reassuring.
The little boy from Waynesboro who played hide-and-seek in the
springhouse at Humpback Rock forty years ago knew, even then, that he
wanted to be a professional biologist when he grew up. I’m not
sure why, but a combination of “Wow, how interesting!” and “Man, that’s
pretty!” played a big role. Spending a warm summer day hunting
tiny populations of mysterious animals, scattered across the crest of
the ancient Blue Ridge, it’s not hard to feel the wonder again.
Keep in touch,
Rob
Figure Captions
Figure 1.
The pioneer cabin at the Humpback Rock Visitor Center, BRP mile 6.
Figure 2.
The old spring house at the Humpback Rock visitor center. Fontigens orolibas inhabits cracks
under rocks inside.
Figure 3.
Spring at Doyle River Cabin, SKD mile 81. Fontigens orolibas is localized
under rocks directly beneath the spring outlet.
Figure 4.
The lightly-colored individual is Fontigens
orolibas (2.9 mm) from a spring on the Blue Ridge, the darker
animal is F. nickliniana from
Coyner Springs in the valley near Waynesboro, Va.
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