Salamanders: Endangered love in the vernal pool

The frost is barely out of the ground but salamanders are not wasting any time in finding love pool side. It is at this time of year that three related salamander species, the Spotted Salamander (Ambystoma maculatum), the Blue-spotted Salamander (Ambystoma laterale) and Jefferson Salamander (Ambystoma jeffersonianum), crawl from their hibernation deep in the forest soil in search of fishless temporary pools of water (called "vernal pools") within forests, which will dry up by early-summer. In these pools the salamanders go in search of love in the night, and if they find a suitable mate the females deposit their egg masses on stems submerged in the water, males then fertilize these eggs externally with their sperm.

Today I went in search of these salamanders with an undergraduate student in my Evolutionary Biology class. The University of Toronto Mississauga is fortunate to be surrounded by forest, and in some of the forests closest to the escarpment overlooking the Credit River one can find vernal pools that attract salamanders. 

As you can see from the photo below, the vernal pool was perfect today - it had lots of water. 

Vernal pool , a temporary body of water, at University of Toronto Mississauga on on March 15, 2016

A quick survey of the waters from the shore (we didn't enter the water so as not to damage this sensitive ecosystem or the species living within it) revealed no eggs. Were we too early? The conditions seemed just right. The student and I went in search of adults under logs near the vernal pool. One log, two logs, three, four .... six ... still nothing (Note: please return logs as you find them if you go in search of salamanders yourself-it is a unique habitat that takes years to make just right). Finally, we worked together to turn a large fallen log at least 4m long and VOILA - a salamander! And this was no ordinary salamander, this was a Jefferson Salamander - an endangered species in Canada since 2011 - see assessment report.

Jefferson Salamander, an endangered species, on its way to mate at the vernal pool

It appears we were not too early after all, we arrived at the very beginning of their mating season.

The individual we found was a dark brown colour with tiny blue flecks along its sides, and 10-15cm long from snout to the tip of its tail - a beautiful animal! Although we would have loved to admire this animal longer, this species is exceedingly rare and we didn't want to bother it any longer than was necessary. We quickly returned the log to the way we found it and released the salamander underneath leaves beside the log.

Let me explain the reason for our caution a little more. Spotted Salamanders and Blue Spotted Salamanders are fairly common, albeit rarely seen because of their subterranean habits. Visiting their breeding habitat is your best chance to see them. The Jefferson Salamander has similar behaviours and habitats to the other two species, but it is both extremely rare and in rapid decline. Although its range extends further south into the U.S.A., in Canada it is only found at a small number of localities in southern Ontario. Of the 87 historical breeding sites of this species (mostly along the Niagara escarpment), only a third remained as of 2011, with this population on our campus being one of those last remaining ones. Is the population healthy? How many animals are there? What is the age distribution? I have no idea, but the population is persisting, possibly due to the reported longevity of these animals (up to 30 years some say!)

I should also note that there is some long-standing taxonomic confusion in this species, with some sexual Jefferson Salamanders and some that form all-female triploid populations (i.e., they have three sets of chromosomes instead of the usual 2 - weird I know, but nature is wonderfully bizarre). It is difficult if not impossible to distinguish these forms without genetics (see work by Dr. Jim Bogart from U. Guelph). Nevertheless, seeing this beauty was a great treat and I hope they have a great year of mating in the vernal pools.