Saturday, February 16, 2008

Liebspeil


Several years ago, during my first adventure in the Ozark Highlands, I spent the night of Februrary 14th wrapped in rain gear and green Wellipers, walking up and down 6 miles of country roads with a flashlight (covered in red cellophane) shuttling salamanders across the road. The spring peepers were deafening that night, thousands gathering at small ephemeral pools scattered throughout the rich, mesic woods. The spotted salamanders were out, too, in droves, crossing the road to get to the same little pools of water to partake in their annual breeding frenzy. (What's the line? "We're from the government, and we're here to help.") All told, by the time I made it back to my drafty cabin well after midnight, I had assisted 129 spotted salamanders and a host of peepers across the road, saving them from death by intermittent truck traffic.

Spotted salamanders (Ambystoma maculatum) can be found in moist woods throughout most of the Eastern U.S., except Florida and parts of South Carolina. Roughly 50 years ago, before rampant habitat destruction, acid rain and widespread feral hog populations, they made up over half of an average woodland's vertebrate biomass. Though seldom seen, their populations (based primarily on breeding period surveys) appear to be stable. Unlike most other salamanders, their populations are largely dependent on healthy small mammal populations. Spotted salamanders occupy the living quarters of short-tailed shrews (Blarina brevicauda) for part of the year; during the winter, they move into holes built by white-footed mice (Peromyscus leucopus), whose burrows are deeper than the shrew's. In fact, range maps of short-tailed shrews and spotted salamanders overlap perfectly. Some suggest that the shrew, a venomous mammal, benefits from salamander secretions, while others think the salamander gains something by the shrew. Whatever the relationship is, it seems to work, making proper land management that supports thriving small mammal populations a priority for salamander conservation.

Stimulated by warm, rainy, winter/early spring nights following a cold spell, spotted salamanders make their way out from under logs, leaf litter, and mammal burrows to return to certain, specific fishless pools of water. Several studies have been conducted in an effort to understand their honing devices, how they find the same pools year after year; many spotted salamanders even return to the pools from which they were born. In light of that, what happens when their traditional pools have disappeared, been paved over, drained? (I hope to hear from my fine herpetologist about this...I've read several studies that suggest the animals just stop breeding, but surely, hopefully, they keep moving until they find something suitable?)

Courtship commences with a dance ritual (dubbed liebspeil, or "love dance"), followed by the release of the spermatophore by the male. The female salamander picks it up with her cloaca, then lays eggs on sticks, rocks, or other vegetation that rests, submerged, at the bottom of the pool. Spotted salamanders lay two kinds of egg masses: the most common consists of a glass-like jelly casing, and the other appears as a milky white gel. In both forms of egg masses, spotted salamanders farm a symbiotic alga (Oophilia amblystomatis) in the laying process. The alga that colonizes the egg masses increases the oxygen supply for the embryos. Brilliant.

So, in about 30-40 days, the eggs hatch and remain in the pond until late March-June. Occasionally, a few larvae will stick around the pond through the growing season, delaying metamorphosis through the following winter. The gravest threat to the success to spotted salamanders during the larval stage is the drying out of the pools. I've seen way too many times close to 100 desiccated black larve plastered on a leaf or a rock (they look like little tapeworms). Explosive breeders, an average egg clutch can contain any number between 20-334 eggs (most clutches contain about 75).

In an effort to spend more time outside, I've volunteered to go back to the park where I lived several years ago to conduct an actual survey of spotted salamanders. It's the common animals whose populations are never tracked, falling under the assumption that their commonality will remain in tact. Flocks containing millions of red knots back east have dwindled to the low thousands in light of the overharvesting of horseshoe crabs (their primary food source). Of course, the lessons of the passenger pigeon needn't be explained. With the spread of feral hog populations, spotted salamander populations in the Midwest may drop as dramatically as they have in the Southeast. But, tonight, I don't want to think about that. I want to think of that warm, rainy night several years ago when I met my first salamanders as they marched to the other side of the road.

1 comment:

Anonymous said...

HE'S ADORABLE! I LOVE his spots!!!How CUTE IS THAT???