The Maple Flats area in southeastern Augusta County is home to a strange array of flora and fauna. Many organisms occur in and around the Shenandoah Valley Sinkhole Ponds at Maple Flats but no where else in Virginia. Plants that usually grow in northern bogs and the southeastern coastal plain can be found growing side by side there. A few species of animals also have disjunct populations that live in the sinkholes.
Maple Flats is underlain by dolomite, a calcareous (calcium rich) rock formed during the Cambrian Period. On top of the dolomite lies a deposit of more acidic quartzite weathered from the nearby mountains, which is responsible for the many plants found growing at Maple Flats that typically grow in more nutrient poor soils. Over time, the dolomite is dissolved by water, leading to its collapse and the formation of the sinkhole ponds.
Many of the sinkholes at Maple Flats could also be called vernal pools, as they dry up in the summer, protecting the numerous species of amphibians and insects that depend on them from predation by fish. All the salamanders in the mole salamander family, including tiger, spotted, marbled, Mabee’s, Jefferson’s, and mole need good quality vernal pools to breed in. Other species that occur only in vernal pools include wood frog and fairy shrimp. Spring peepers also commonly breed in vernal pools, but they can tolerate other types of wetlands.
The eastern tiger salamander, which has a fairly large range in the coastal plain up through the mountains of Kentucky has a disjunct population in the vernal pools at Maple Flats. Tiger salamanders are state endangered, have very few other populations in Virginia, and most of them are far away in the coastal plain. Eastern tiger salamanders spend most of their time deep underground, coming out only on warm, wet nights in February to breed. They stay near the vernal pools for a few weeks afterwards before they disperse back underground. Some friends and I decided to go to Maple Flats in late March to look for tiger and other salamanders.
When I stepped out of the car into the warm, damp spring air at Maple Flats I felt good about our chances of finding salamanders. If I was a salamander, I’d be out on a day like today. I breathed in the damp air, smelling the gentle spring scent of the forest. We started down the dirt road — overgrown in the summer by black huckleberries and common greenbrier. To my right a trickle of water ran through the sandy soil underneath a canopy of black gum and oaks.
A pine warbler sang, the musical trill of its voice coming from an old pitch pine growing next to the trail. Looking up, I caught a flash of bright yellow as the pine warbler flitted in between dense clumps of pine needles. It sang again, and Tucker noticed the chip of a second pine warbler coming from across the path.
We came to the first sinkhole, a deep pit in the landscape, but barely twenty feet wide. We made our way down the steep banks to the water’s edge, listening to the faint chorus of spring peepers in the background. The water in the pool was crystal clear — I could see every leaf at the bottom. A northern cricket frog hopped across a rock in front of me, pausing long enough for us to see every wart on its back.
Emily said she had heard that this particular pool sometimes held fairy shrimp, a species of fresh water crustacean that lives in vernal pools, but none were present that day — perhaps it was too early in the season.
As we walked back toward the trail, I reached down to lift a log as I had been doing all morning. To my surprise, I saw a three-inch long marbled salamander curled up under the log. Further down the length of the log, the head of a second marbled salamander poked out of its burrow. The silvery blotches along the salamanders’ damp backs sparkled in the sun.
Like tiger and spotted salamanders, marbled salamanders breed in vernal pools, but unlike the other mole salamanders they breed in the fall instead of the spring, so I hadn’t thought we would see one. I guess they were out to feed near the surface in the damp weather. I carefully put the log back, making sure not to crush the salamanders.
We set to work flipping over rocks and logs, always restoring them to their original position after looking underneath, slowly working our way toward the next pool. We found a few more marbled salamanders, but nothing else for a while. Suddenly, Theo yelled, “I have a salamander, but I don’t know what it is!” By the time we got there the salamander had disappeared into the ground. Theo said he was pretty sure that he had seen a slimy salamander. I moved a particularly large log off the ground. Underneath lay a particularly large salamander. It was longer than my hand and fairly chunky; its body was black with tiny white spots. I didn’t know until I picked it up, but its body was also covered in thick super sticky slime. I called over my friends and showed them the slimy salamander as we discussed its ID.
Around 10 species of slimy salamander live in the Southeastern US, and most of them look very similar. Lucky for us, only two species, the white-spotted and northern slimy salamanders live in our area, but they are almost impossible to identify. We settled on a tentative ID of white-spotted slimy salamander, based on habitat. If anyone has any insight into the identification of slimy salamanders at Maple Flats, please let me know.
After we let the slimy salamander go, I was beginning to worry we weren’t going to find a tiger salamander, as I felt like we’d flipped every good-sized rock in the area already. We decided to walk around the pond in search of more promising salamander habitat. The pond on our left was a large artificial one, half filled with water and half covered in a dense thicket of buttonbush. Four green-winged teal flushed suddenly out of nowhere as we rounded a bend. On our right lay another pond, probably also artificial, this one full of water and bordered by smooth alder. I saw a small trickle of water running through patches of lush Sphagnum moss in front of us. A few minutes later, we’d found a northern dusky salamander under a log in the seep. On our way back up to the trail, someone kicked over a rotting log. Underneath lay a large sleepy spotted salamander, its eyes covered by a dirty membrane.
Two mole salamanders in a day was exciting, especially since the spotted was a lifer for my friend Tucker, but where were the tigers?
We spent the rest of the day walking to Spring Pond, the largest of the ponds at Maple Flats. We never did see an eastern tiger salamander, but we did see six other interesting species. Next year, I think it might be better to go earlier in the year.