by Fred Schueler
Bishops Mills Natural History Centre
RR#2 Bishops Mills, Ontario, Canada K0G 1T0
Report of the talk “Salamanders: Unseen, Unheard, but NOT Unimportant” which was to have been given by Mike Oldham to the Mississippi Valley Field Naturalists (MVFN), 26 January 2012; the 4th lecture in MVFN’s 2011-2012 natural history lecture series: Trends in Flora and Fauna. The report was written by local naturalist Fred Schueler, who was to write this report and thank the speaker, but who also delivered the talk when Mike was prevented by weather from reaching Almonte, after Cathy Keddy reconstructed Mike’s presentation from e-mailed files.
Blue-spotted Salamander Ambystoma laterale (upper photo courtesy Cathy Keddy) is the most frequently encountered species in our area, often wandering into basements or garages, or turned up under wood; the red colour of the terrrestrial stage of the red-spotted newt serves as a warning to predators that the eft is poisonous. Efts such as this one photographed during MVFN’s 2010 bioblitz near Almonte are the only salamanders you’ll see wandering aaround in daylight (lower photo courtesy Karen Thomson)
On 19 Jan 2012 3:26 PM, Oldham, Michael (MNR) wrote:
> I ended up turning around and heading home, so won’t be at this evening’s MVFN meeting this evening. So sorry… It is still snowing very heavily here with lots of accumulation… I just got home and driving back from where I called, between Norwood and Havelock, was even worse than the drive there. Blowing snow, freezing rain, poor visibility, slow snow plows with impatient drivers and truckers trying to pass, slippery roads, snow squall warning in effect, cars in the ditch, and the MNR minivan I was driving is not very good in slippery conditions. I was averaging 40-50 km/hr, often slower in long stretches behind snow plows or sanding trucks, half the speed under normal conditions, so my estimated 3 hr drive would have been 6 hrs, unless conditions improved. I hope the snow squalls abate before they reach your area and affect people travelling to and from Almonte.
I was setting out to drive the Dwyer Hill Road to Almonte when the wife banged on the van window to announce she’d just read Mike’s e-mail, but I was soon setting out again with the plan that I would give Mike’s talk from his e-mailed presentation. All the way up the Dywer Hill Road there was no snow at all, though things were blizzard-like soon after I reached Almonte.
I began the lecture by introducing Mike Oldham, herpetologist and botanist at the Natural Heritage Information Centre (NHIC, Ontario Ministry of Natural Resources) in Peterborough, co-founder, in 1984, of Ontario’s Herpetofaunal Summary, the first modern atlas of “reptiles” and Amphibians, and the person you turn to when you need a copy of any paper relevant to Ontario natural history (and often he’s sent it to you before you ask). I illustrated his scope as a field naturalist from the top of my e-mail SENT box – correspondence about introduced Xerolenta snails and Dyssodia Dogweeds along Ottawa highways, freshwater mussels he’d collected all across southern Ontario, a new book about European Sedges, and the status of invasive Cattails in Ontario…
So Mike is known for his interest in spectacular but inconspicuous creatures, and Salamanders are leading members of this group. This report is compounded of his notes, and my local knowledge of Salamanders in Eastern Ontario.
Salamanders retain the long-tailed, four-limbed shape of primitive land-dwelling Vertebrates, overlaid by a wide range of specialized adaptations. They diverged from the tailless Frogs some time before the earliest known Salamander fossils, from the Middle Jurassic, 164 million years ago. There are now about 550 species of Salamanders in the world. Among provinces, Ontario has the greatest number of species, probably because it is closest to the southern Appalachian region, which is the world centre of Salamander diversity. Our Salamanders range from 35 mm to almost half a metre in length, and show remarkable variation in life histories and habits. Some spend their entire lives in the water, others live on the land but breed aquatically, and some have an entirely terrestrial existence. Salamanders may breathe via gills, lungs, and skin, or can be lungless and breathe only through their skin. Moisture is thus a very important factor regulating their distribution, and they tend to be active on the surface mostly on rainy nights, when potential observers tend to seek shelter.
Salamanders are elusive, and in addition to being rarely seen at the best of times, and on the formerly ploughed and trampled lands of eastern Ontario, they’re often much rarer than they were before settlement, though because of their effectiveness as predators they are often regarded as “keystone predators” in intact forest ecosystems of eastern North America.
Thirteen species of salamanders are known from Ontario, including six that are legally listed as “at risk” either federally or provincially: none of these, and all of the others, occur in eastern Ontario. The “at risk” species fall into 2 groups, stream salamanders of the Niagara Peninsula, and hybridizing Ambystoma Mole Salamanders of southwestern Ontario.
There is only a single confirmed record of the Eastern Tiger Salamander (Ambystoma tigrinum), from Point Pelee in 1915. The Jefferson Salamander (A. jeffersonianum), is similar to, and hybridizes with the widespread Blue-spotted Salamander, but it is restricted to scattered sites around the southern Niagara Escarpment, the Greater Toronto and Golden Horseshoe areas, and is generally threatened by destruction of its habitat. The Small-mouth Salamander (A. texanum), is restricted in Canada to Pelee Island, and also part of the hybridizing complex there.
There are two species of Dusky Salamanders, genus Desmognathus, in Ontario, both restricted to the Niagara River Gorge. For decades there’d been attempts to replicate an old record from “across from Buffalo,” but in 1989 James Kamstra and Wayne Weller found Dusky Salamanders in two small streams in the Niagara Gorge, and it turned out that one of these populations was D. fuscus, the Northern Dusky, and the other D. ochrophaeus, the Allegheny Mountain Dusky. We can see the habitat of both of these species, in New York across the St Lawrence River from eastern Ontario, but they never made it across the St Lawrence lowlands to Ontario. Another Stream Salamander species, the Spring Salamander (Gyrinophilus porphyriticus) is known only from three Niagara Peninsula larvae collected in 1877. There is also an old larva of this species supposedly from Britannia, in Ottawa, but decades searching hasn’t turned up a population here.
Eastern Ontario is not a particularly diverse area for salamanders, but the seven species found here have a variety of different life histories and are among our most poorly known Vertebrates.
The Mudpuppy (Necturus maculosus) is Ontario’s largest salamander, reaching a foot or more in total length. These salamanders are permanently aquatic and have feathery gills behind the head, and other features of the larval morphology that other species lose when they mature. Mudpuppies occur in larger rivers and lakes throughout southern Ontario, as far north as Thunder Bay and the upper Ottawa River, though their distribution is poorly known due to their permanently aquatic habits. They’re known from the Rideau, Mississippi, and Madawaska rivers, on the basis of only a few records. The one place they can be easily seen in eastern Ontario is during the winter at Mudpuppy Night in Oxford Mills – http://pinicola.ca/mudpup1.htm – where many Mudpuppies from an abundant population are out in the open during their winter activity period.
The Salamanders with the least surprising life history are the Ambystoma “Mole Salamanders,” so called because they spend much of their lives underground – like frogs these live on land and come to ponds to lay eggs in the spring, which hatch into larvae which, like tadpoles, transform to leave the water to live on land until they come back to breed in ponds as adults.
The Blue-spotted Salamander (A. laterale) is the most frequently encountered species in our area, often wandering into basements or garages, or turned up under wood that has been resting on the ground. Adults are about 13 cm in total length; they are black or dark brown with variable amounts of bluish spots or flecks. This species is closely related to the Jefferson Salamander, which does not occur in eastern Ontario, and the two species hybridized historically to produce unisexual polyploids which contain multiple sets of chromosomes from both the Jefferson and Blue-spotted Salamanders and are almost indistinguishable from the parental species except through genetic testing. These polyploid populations are almost entirely female and usually must mate with a male of one of the parental species to reproduce, though usually rejecting the chromosomes from his sperm. There are also situations, especially in disturbed habitats, where the sperm is incorporated and the number of sets of chromosomes increases as high as seven; these hybrids have the chromosomes of their “parent” species, but the cytoplasm of a southern species which does not occur in Canada; much of the research on these hybrids has been done by Dr. James Bogart and students at the University of Guelph.
At one time the polyploids occurring in eastern Ontario were called a separate species, Tremblay’s Salamander, larger and less spotted than ordinary Blue-spots, with two sets of Blue-spotted genes and one of Jefferson genes; but since it doesn’t reproduce sexually it is no longer considered a separate species.
Our other Ambystoma is the Yellow-spotted Salamander (A. maculatum). This large, blackish Salamander has two rows of large yellow spots on its head and along its back and tail. It can grow to over 20 cm in length. It’s fairly common on the Shield, including Lanark County, but is restricted to mature woods on sandy dunes in the limestone country of easternmost Ontario. The large, slow-hatching, jelly-swathed egg masses are conspicuous in woodland breeding ponds in the early spring.
The Eastern or Red-spotted Newt (Notopthalamus viridescens) has a life-cycle that differs from any other Ontario salamander – the larvae transform into a terrestrial stage known as the “red eft” and spend 2-4 years on land in the woods. They then return to the water to become mature aquatic adults. Adults have expanded tail fins, and are dark above, often a greenish-brown colour, with prominent black-ringed red spots on their sides; efts are orange-red, with the same red spots, but narrow tails. The red colour serves as a warning to predators that the eft is poisonous, and efts are the only Salamanders you’ll see wandering around in daylight. In eastern Ontario the distribution of Newts is very scattered, and they may be declining.
The final, and largest family of Salamanders is the lungless Plethodontidae. We have two specialized uncommon species, and one that is widespread and relatively abundant.
The species with the most specialized habitat is the Four-toed Salamander (Hemidactylium scutatum). In May the females leave their woodland habitat and form cavities in moss, typically Sphagnum, overhanging water, where they lay their eggs. When the larvae hatch they wriggle down through the moss into the water where they live until they transform. Although the Four-toed Salamander has only four toes on its hind feet while similar Salamanders have five, the tiny toes are not a particularly useful identification character – better are the constriction at the base of the tail and the underside which is bright white with bold black spots, quite unlike the greyish underside of the Red-backed Salamander, with which it could be confused. Undoubtedly the species is more common in eastern Ontario than very few old records indicate – you have to go to bogs or other moss-banked ponds or ditches during the breeding season to have the best chance of finding them.
Another small, slender Plethodontid Salamander is the Two-lined Salamander, Eurycea bislineata, almost always found in or very near running water or gravelly seepages. This species is generally gold-coloured with two dark longitudinal stripes down its back. Eggs are laid beneath flat rocks in streams and the larvae live in the stream until they metamorphose. The best way to find them is to flip over rocks just at the edge of a stream or lake. Two-lined Salamanders are not found in southwestern Ontario, but are locally common in a band from Georgian Bay, across Algonquin Park to Quebec, and south to the St. Lawrence River, though they are found east of the Shield in Ontario only in a very few sites where water flows into streams through seepages of clean gravel. Lanark County is part of this range where the species is fairly common; there used to be a population below the dams in Almonte, but the new hydro station has been built over the site where they occurred.
The Eastern Redback Salamander, Plethodon cinereus, is usually regarded as the most abundant Vertebrate in the forests of northeastern North America. These Salamanders act as keystone predators to regulate the invertebrates of the forest floor community, and through them the character of leaf litter decomposition, soil, and nutrient cycling in the forest. Red-backed Salamanders are an exception to the rule that our Amphibians lay their eggs in water, since they lay their eggs in moist spots inside or beneath rotten logs and the entire larval stage of the salamander occurs inside the egg, as they are attended by the mother.
The Small Eastern Plethodon Salamanders, like several other of the common Vertebrates in our forests (Ruffed Grouse, Screech Owls, and Redbelly Snakes), have distinct reddish and greyish colour forms. Rufous and ashy are plausible colours for cryptic forest creatures, as the colours of freshly dead and decayed leaves, and they are produced by the different hues of the melanin pigments – phaeomelanins producing reds and eumelanin grey or black. In Plethodon these morphs are ‘leadback’ – unpatterned and charcoal gray, and ‘redback’ with a reddish dorsal stripe. In New England leadbacks are more frequent in warmer localities, and it has been found that the morphs forage at different temperatures, with a corresponding difference in basal metabolic rates. Across most of southern Ontario populations are mixed, with leadbacks rarely frequent, but in eastern Ontario south of Ottawa and east of the Frontenac Axis there are no redbacks. Reasons for this monomorphic region, or genetic differences between the populations, have not been studied.
Pleistocene ice sheets wiped out any native Earthworms that had lived in Canada, leaving North American species, in the family Megascolecidae, only where glaciation was incomplete, on Vancouver Island and the Richardson Mountains of the Yukon. The 25 or so European species that now live in Canada, in the family Lumbricidae, are thought to have come in the rootstocks of plants imported by settlers or in soil used for ballast in ships. Nowadays, in many Ontario forests, last year’s leaves seems to be all there are…. the rest have been pulled underground and consumed by Earthworms, and increasingly many naturalists have noticed that Earthworms are changing the ecology of forest floors, first in urban parks and now even in protected old growth forests. The missing leaf litter was home to complex communities of everything from snails to Nematodes to Springtails to Centipedes to Beetles to Salamanders, and to the extent that their habitat is gone, the fauna must be gone from the forests with minimal leaf litter. The invasion of wooded areas by non-native Earthworms can also lead to the decline in some native plants, such as rare woodland Orchids that depend on a rich humus layer, as well as facilitating the invasion of wooded areas by non-native plants.
In 2006 James Gibbs and Nancy Karraker found that the frequency of leadbacks had increased with, but faster than, increasing temperature over the course of the 20th century. It’s possible that the excess increase in the leadback morph, above that predicted by climatic warming, may be due to the effects of Earthworms in warming the soil, and in 2010 at the Shaw Woods in Renfrew County this result was found in an Earthworm-ravaged, but otherwise protected, oldgrowth woods, where reduction in litter depth by Earthworms is the main observed longterm disturbance.
Top: Joe Crowley’s photo of a redback (Plethodon cinereus) on Earthworm castings. Bottom: Bev Wigney’s photo of a leadback Plethodon, also on Earthworm castings.
The first way to contribute to our knowledge of Salamanders is through Ontario Amphibian & Reptile Atlas – once you get out into habitat and ‘turn cover’ to discover these creatures, you can report your records online – http://www.ontarionature.org/protect/species/herpetofaunal_atlas.php – or you can co-operate with our effort to resample places where Plethodon have been collected in the past – http://pinicola.ca/thirty/pcin_2012.htm – to see if abundance or colour morph ratio of this species have changed in recent decades.
author’s contact information: Fred Schueler
Bishops Mills Natural History Centre
RR#2 Bishops Mills, Ontario, Canada K0G 1T0