Salamander Night is a time of cheap thrills for the naturalists of Nova Scotia, requiring only a flashlight on the first rainy evening in April over 9°C. Under these conditions several of the province’s amphibians depart their wintering grounds for the ponds in which they’ll soon breed, and no species is more noteworthy in this short, seasonal migration than the Spotted salamander, who, about a decade ago, was caught breaking the rules of biology.
This unassuming salamander, it turns out, hosts photosynthetic algae in the cells of its skin, the biological equivalent of having solar panels strapped to one’s back. These algae produce oxygen and carbohydrates metabolized by the cell, and in return the cell provides a wealth of waste nitrogen - microbial miracle grow. Such symbioses were thought to be impossible among vertebrates, equipped as we are with exceedingly hostile immune systems, primed to pounce on anything not recognized as “self,” which is a pretty useful trait during a pandemic.
Not only is the Spotted salamander special in this regard, it’s difficult to spot outside of Salamander Night, which, this year, began April 13th in southern Nova Scotia. It was declared over Facebook by retired ecologist and conservation biologist Sherman Boates, a veteran of both Acadia University and the Wildlife Division of Nova Scotia’s Department of Natural Resources, forcing enthusiasts into the darkness of rural Nova Scotia where their flashlights fell on these remarkable amphibians, exciting cellular algae with artificial photons.
Populations of the Spotted salamander have been on a steady decline for sometime now, said Sherman, because this local migration takes them across rural roads where they’re routinely crushed. In fact, cars pose a greater threat to this long lived salamander than any other, some individuals known to live 35 years, their reproductive potential dashed over the asphalt en masse.
But Salamander Night 2020 (which actually lasts 7-10 days) turned out differently. Scanning the roads of rural Nova Scotia, as he has many years prior, Sherman encountered remarkably few fatalities.
“Only a couple were run over, and we saw no cars,” he said. “People aren’t going out as much, so there isn’t as much traffic density and wildlife isn’t being disturbed or killed nearly as often.”
For the first time, Sherman found clear evidence that the Spotted salamander, and in fact all species contending with the iron chariots of humanity, were going to have a very good year.
So What’s Happening, Exactly?
As Canadians spend an inordinate length of time indoors, satisfying our communicative impulses with heavy doses of social media, we’ve been inundated with heartening stories of wildlife flourishing in our widespread absence from roads, beaches and city streets, some faked, but many genuine, such as deer and coyotes finding the abandoned heart of some metropolis, or turtles laying their eggs in sands untrampled by tourists. We can be certain that things are changing out there, even if the people best equipped to interpret those changes are relegated to their living rooms, left with only an educated guess.
“Finding evidence is going to be the trouble at this point,” said Sherman Boates. “Hopefully scientists will get around to evaluating all this.”
Suzanne MacDonald is a psychology professor at York University who studies animal cognition, from the rabbits in her backyard all the way to Kenya, where she would be right now if it weren’t for Covid-19, working with lions, elephants, hyenas and a suite of primates. She’s dedicated her career to understanding how animals think, in order that we might better conserve and co-exist.
She has spent a great deal of time studying raccoons in the Greater Toronto Area and how they’ve adapted themselves to humanity. For example, there are several major roads and highways through the city which raccoons will only attempt to cross between 4-5am, not because the species is strictly nocturnal, but because that’s when traffic finds its minimum. Several species, in fact, have come to respect the comings and goings of humanity, like coyotes following train tracks into the city at night so as to avoid human eyes, or bunnies assaulting backwards when the owners are typically at work.
“They get to know our routines, and that’s why this pandemic is fascinating because our routines have completely changed,” she said. “There’s no traffic, so you’re probably going to see raccoons out in the middle of the day, because there’s no pressure on them to wait until we go to bed.”
Urban raccoons have been known to establish home ranges of about three square blocks, but during Toronto’s quiescence, and that of major cities across the country, Suzanne expects they will expand their territory, assuming home ranges similar in size to those they establish in the wild - about 20 square kilometres. Instead of bumping against traffic and towering primates, they will instead bump into each other, setting off a series of turf wars.
“If I had to speculate wildly,” Suzanne said of city ecology, “I’d say the prey population of bunnies and rodents will go up, the predator population will go up, there might be a boom/bust cycle over the next few years as a result, and several animals will be venturing into areas they haven’t before.”
But not all species will benefit from the disappearance of human beings. Some, she explains, are just too far gone.
“I don’t want to be depressing, but turtles are pretty much whipped out anyways,” she said. “There are so few of them left.”
Turtles, she said, illustrate best the threat posed to long-lived species by the ubiquity of motor vehicles, especially when the species in question prefers to lay its eggs in the loose dirt along roadsides. The benefits of reduced traffic during Covid-19 will be too short-lived to make a difference for such slow-breeders, and will require longer-term solutions.
Just this April, construction of a turtle corridor was completed on Heart Lake Road in Brampton, Ontario, where many thousands of nesting turtles are killed, devastating local populations. Hope for turtles might be found in this and similar projects, if not in the temporary quiet of Covid-19. Of course MacDonald has yet to visit the new corridor, and will be unable to study its effectiveness until a break in the pandemic.
“This is going to be the lost year,” she said of wildlife research.
Dialing Down the Decibels
In the oceans of yore, baleen whales communicated over enormous distances using a range of low-frequency songs which carried quickly and clearly through the watery aether, in particular that of the Blue whale, the largest and loudest animal in all of natural history which, it’s been suggested, can converse over thousands of kilometres under natural conditions. Trouble is, those natural conditions haven’t existed for many decades now.
By way of shipping traffic, seismic airguns searching for oil and gas, military sonar, fishing, even recreational boating, we have steadily increased the ambient noise of the world’s oceans. It’s getting awfully loud down there, and the consequences are only now dawning on us.
Lindy Weilgart of Dalhousie University, Halifax, has studied underwater acoustics since the early 1990s, beginning with the communicative clicks of Sperm whales, then transitioning to anthropogenic sound and its consequences for marine ecology.
“It’s becoming more and more obvious that almost all ecosystem components, almost all marine life, is adapted to sound,” she said, and that’s no coincidence.
Sound travels much faster and more efficiently underwater than it does in air, and the oceans of the world were murky even before the human enterprise complicated things, so eyesight has always come second in the arena of evolution. Whether our contributions to underwater noise are sudden, such as with regular bursts of seismic testing, or drawn out, as with shipping traffic, all this extra noise “smears” out over great distances of ocean, causing a steady human roar which, it’s believed, drowns out the communication of wildlife, dramatically reducing the distances over which whales can communicate, and it has more pervasive impacts still.
Among other things, underwater noise pollution can damage the hearing structures of wildlife and cause developmental delays, behavioural change, decreased reproductive success, lessened immune responses, the deformation of embryos, displacement from habitat, reduced feeding and losses to the fishing industry. It can also kill plankton, the foundation stone of marine ecology. Lindy has compiled a list of species for whom the deleterious effects of noise pollution have been demonstrated, a list which, to date, includes 36 species of invertebrate, 66 species of fish and roughly 30 species of marine mammal.
Exactly how much louder things have gotten over the “ancient ambient,” as Lindy describes it, is a very difficult question to answer, because monitoring started relatively recently. She uses 60-70 decibels as a rough baseline for natural ocean volume, a baseline which is easily exceeded along shipping lanes which can reach 180 decibels, and in the vicinity of seismic tests which surpass 170 decibels. These are huge spikes, and it doesn’t take much to frustrate whale song.
“They’re just not able to communicate like they used to,” she said.
Lindy can’t be specific because she doesn’t have access to the data, but is confident underwater noise pollution has been tempered by Covid-19 and resulting reductions in human activity on the world’s oceans, and that in some form or another, marine ecology is enjoying a respite right now.
There is precedent. Following the terrorist attack of September 11th, 2001, there were worldwide reductions in shipping and air traffic, and an unwelcome opportunity for members of the New England Aquarium to monitor drops in underwater noise pollution in Canada’s Bay of Fundy, feeding ground of the critically endangered Northwest Atlantic Right whale.
What they observed was a 6-decibel decrease in ambient ocean volume and a corresponding drop in stress hormones from the feces of the aforementioned whales. Their resulting peer-reviewed paper acknowledged that underwater noise pollution causes habitat displacement, behavioural changes and alterations in the intensity, frequency and intervals of whale calls, and that reductions in human noise seem to alleviate the chronic stress we’ve imposed on them.
But then as now, shipping traffic hasn’t stopped outright, and institutions like Canada’s Department of Fisheries and Oceans have yet to collect the fix hydrophones they employ across the Atlantic Coast and evaluate any change. This work is expected to commence in fall.
David Barclay, however, of Dalhousie’s department of oceanography, has compiled extremely telling data from Canada’s Pacific Coast, where he and colleagues have remote access to acoustic monitoring stations maintained by Ocean Networks Canada. Of the four stations they consulted, two were in the Strait of Georgia immediately outside the Port of Vancouver, and two were in deep water off the continental shelf.
“We’ve shown that there has been a consistent drop in noise since January 1st,” said David.
In the Strait of Georgia, from January to April, noise dropped a weekly average of 4-5 decibels - not dissimilar to the Bay of Fundy following 9/11 - and off the Pacific shelf, 3,000 metres underwater, ambient noise has dropped 1.5 decibels, all of this corresponding with a 20 per cent drop in exports and imports from the Port of Vancouver.
Barclay’s data is undergoing peer review with the Journal of the Acoustical Society of America. It will have important implications for how underwater noise pollution can be managed for the sake of marine ecology, and illustrates clearly the dialing down of decibels during this pandemic.
Lessons From A Difficult Time
“What this pandemic has brought home to me is how much we normally limit wildlife movement,” said Suzanne MacDonald. “All it takes is a few weeks of not filling roads and sidewalks for animals to go out and give life a shot.”
This is a sentiment shared by many in the conservation community, and by others admiring wildlife through locked windows around the globe. Species of bird and mammal and amphibian and reptile have proven themselves remarkably quick on their feet when presented with the vacancies of civilization.
The research and conservation communities have been trapped indoors at a pivotal time, and until their non-essential designation is reevaluated, the true scope of change in the migratory and resident wildlife of Canada will remain mostly obscure. The clearest lesson at the moment, at least for some in tune with the needs of the planet, is the extent to which humanity is capable of reinvesting itself, the sort of social engineering which might ultimately be necessary to address both climate change and species extinction in days ahead, empowering us to bike instead of drive, avoid certain roads during breeding seasons, lessen shipping traffic and everything else previous dismissed as impossible. The evening after he admired his first Spotted salamanders of the season, uncrushed by the tires of a restless humanity, Sherman Boates had exactly this revelation.
“All you can say is that there’s amazing evidence human beings can change their behaviour if we have a good reason,” he said.
Comments
The animals assume we have finally gone extinct, or so my son suggests.