By Sharon Oosthoek

Assessing the impact of climate change on wildlife is tricky business. Any given year may be warmer or wetter than usual and still have nothing to do with climate change. That’s called weather.

Gambo, Newfoundland trapper Clarence Pritchett knows all about that. In his 35 years of trapping, he’s seen animals that have suffered through bad winters, and he’s seen the opposite.

This past winter was unusually temperate and animals such as otters and mink are now plump and healthy. “It’s not a pattern though,” says Pritchett. “We have good winters and bad winters. It changes drastically with the North Atlantic.”

But climate change is about patterns. Not seasonal or even yearly fluctuations, but long-term changes in temperature, precipitation, wind, and even ocean currents.

So a decade or more of unusually warm temperatures or lots of snow may signal climate change.

“In order to make that link, you have to have a long enough time series,” says Gary Stern, senior research scientist at the Department of Fisheries and Oceans in Winnipeg. “I would say 10-15 years of data on an annual basis … You have to monitor the biota (plants and animals) but you also have to the monitor the system that’s changing and try to link the two together, which is a difficult thing.”

Paul Wilson, a wildlife geneticists with Ontario’s Trent University, agrees that long-term patterns are key, and urges meticulous research to set baselines for comparison.

“I think we as scientists have to be careful we’re not jumping on the climate change bandwagon and trying to attribute everything we see to climate change,” says Wilson.

Other human-induced changes – fragmentation, pollution and introduced species – also make it hard to separate out what can and can’t be chalked up to climate change.

That’s why Jody Allair, a biologist with Bird Studies Canada, counsels caution.

‘Our scientists are finding it difficult to tease apart the variety of factors contributing to (bird) range shifts or to decipher an overall pattern,” says Allair.

Southern Yukon Tlingit elder Stanley James has also seen wildlife shifting ranges in the past few years, and like Allair, can’t say with certainty what is behind it.

“We’ve had polar bears coming down this way now, on the Dempster Highway. We have cougars coming in from the south. And then we’ve had muskox,” says James. All are unusual sightings near his home in Carcross.

“The animals know there is a change that is happening,” he says. “We used to have four feet of snow when I was on the trap line 60 years ago. Now you only have about 17 or 18 inches of snow.”

With these caveats in mind, we offer here a sampling of intriguing, and often troubling changes in the lives of Canada’s wild animals.

Health and Welfare:

Perhaps no animal has received more attention than the polar bear when it comes to climate change. It’s hard not to notice when one of the world’s largest mammals starts losing weight and having fewer cubs.

Scientists believe the declining health of populations in the Hudson Bay regions of Manitoba and Ontario is linked to the earlier break up of sea ice. Because polar bears hunt seals from the ice, and because seals are their main prey, less time spent on ice means less time fattening up before they are forced ashore for the summer.

Recently, scientists and local First Nations have noticed that spring ice break up in the Hudson Bay region is happening as much as three weeks earlier than it did in the 1970s. The fear is that if this trend continues, the health of polar bears will decline further, leading to a dramatic drop in numbers.

The Committee on the Status of Endangered Wildlife in Canada already classifies polar bears as a species of special concern and is blunt in its assessment of the bear’s future:

“The species cannot persist without seasonal sea ice. Continuing decline in seasonal availability of sea ice makes it likely that a range contraction will occur in parts of the species range.”

Crossover appeal:

1995 was a very good year to be a southern flying squirrel in Ontario. In fact, it marked the start of a series of nine unusually warm winters that saw the rodent creep north into the range of their larger cousin, the northern flying squirrel. By 2003, they had shifted about 200 kilometres north.

While it was a big deal for the squirrels, the incursion wasn’t widely noticed by humans. The two species are closely-related and look much alike with their large dark eyes and the furry membrane between their front and rear legs that allows them to glide.

But someone was watching – wildlife geneticists at Trent University, and they wondered if the two species were crossbreeding and having hybrid babies.

When the researchers trapped flying squirrels and analyzed the DNA in their hair, they discovered that was exactly what was happening, says Paul Wilson a wildlife geneticist at Trent.

Wilson says it is likely the first report of hybridization following the expansion of a species’ range due to modern climate change.

While an unusually cold winter in 2004 beat back southern squirrels by about 240 kilometres, they have nearly regained that territory over the past six years.

But is such hybridization good or bad?

“When you’re dealing with hybrids, one of the concerns is do the hybrids replace the parents at some point? We don’t know yet how viable the hybrids are in terms of reproducing with each other, “says Wilson.

Neither species is currently considered at-risk in Ontario, but the northern flying squirrel is endangered in Pennsylvania, where hybrids have also been found.

Yet such hybrids may turn out to be Mother Nature’s insurance policy. That is, the more diverse a species’ genes, the better it can survive changes in temperature and precipitation.

“One could look at these hybrids as a creative reshuffling of the genetic material for a changing landscape,” says Wilson. “I mean climate change isn’t going to go away … maybe these hybrids are emerging as the most adapted flying squirrel for the changing landscape and climate.”

Pollution problems:

Levels of PCBs, DDT and mercury are rising in burbot in the MacKenzie River near Fort Good Hope, NWT, and scientists say climate change is the most likely culprit.

In a study published earlier this year, researchers found the level of PCBs in the fish rose by up to six times between the mid-1990s and 2008. Levels of DDT increased by three times, and mercury by 1.6 times over the same period.

It was not what scientists expected – PCBs and DDT have been banned since the mid-80s and their levels in the environment have gone down. Mercury levels have stayed fairly steady. By rights, the levels of such contaminants in burbot should not be increasing.

“It completely took us by surprise,” says Gary Stern, senior research scientist with the Department of Fisheries and Oceans in Winnipeg, and lead author of the study.

So what happened? Stern and his colleagues say the answer is climate change.

Increased northern temperatures means the time during which ice covers local lakes and waterways is much shorter than it used to be. Less ice cover means more sunlight penetrating into the water, allowing more algae to grow.

Because PCBs, DDT and mercury have an affinity for carbon, and algae is carbon-based, they gravitate to these tiny aquatic plants.

“Think of algae as a sponge that soaks up mercury, PCBs and DDT dissolved in the water, that are floating there not doing anything. The algae make the contaminants more bioavailable,” says Stern.

Tiny aquatic animals called zooplankton eat the contaminant-soaked algae.  Smaller fish eat the zooplankton, which in turn are eaten buy the burbot. People then eat the burbot. Each step up the food chain, the contaminant load increases.

While Stern says the levels are still below what Health Canada considers safe to eat, he worries about the future.

“Based on the trend were seeing here, by 2015, if levels continue to go up, the levels of mercury could rise to a level where Health Canada will have to intervene,” he says.

Flawed thaw:

Peary caribou numbers have plummeted by nearly three-quarters over the last three generations and experts say a changed freeze-thaw pattern in Canada’s north is to blame.

This small subspecies of caribou lives in the Northwest Territories and Nunavut, where they eat ground vegetation. But more frequent thawing and freezing is coating the ground with a layer of ice, cutting off caribou from their main food source.

Many animals have quite simply starved to death and the future looks equally bleak.

“Because of the continuing decline and expected changes in long-term weather patterns, this subspecies is at imminent risk of extinction,” according to a report from the Committee on the Status of Endangered Wildlife in Canada, which lists the Peary caribou as endangered.

Some scientists now worry other sub species of caribou, for example those in northwest British Columbia, will soon have the same problem.

B. C. ecologist Jim Pojar recently studied the potential impacts of climate change in the region on behalf of the Taku River Tlingit First Nation and the province.

Pojar says that over the past 20 years or so, he’s seen more frequent episodes of thawing and freezing in that area.

“The crusted snow and caribou story has been playing out for a long time and depends on locality and winter weather in any given year. Climate warming increases the frequency of winter thaw-freeze events,” says Pojar, a former provincial forester and retired executive director of the Canadian Parks and Wilderness Society.

Francois Paulette, Dene elder and former chief of Smith’s Landing First Nation, NWT, says unusual spring and fall rains have crusted the snow in his region too, making it harder for local caribou to feed.

And he says more frequent forest fires have wiped out local caribou feeding grounds, making those that remain inaccessible. “The caribou don’t like going through burned areas to get to food,” he says.

While he suspects a connection between climate change and more frequent fires, he’d like to see some solid research on that. “They key word is monitoring. You need baselines,” he says.

Ice issues:

A nearly 20-year study of seabirds in northern Hudson Bay shows a troubling mis-match between when chicks are born and when food is most abundant.

Every spring between 1988 and 2007, scientists with the National Wildlife Research Centre have been recording when thick-billed murres on Coats Island lay their eggs. They’ve also been keeping track of when half of the bay’s winter sea ice has receded – an important date because it triggers a pulse in marine life on which the birds depend to feed their chicks.

The researchers have discovered that the date at which half the area’s winter sea ice is gone has advanced by an average of 17 days. But the date on which the murres lay their eggs has advanced by only five days.

“The change in timing of ice clearance is creating a mismatch with the timing of breeding so that the chicks are being fed after the date of optimal food availability,” says senior research scientist Anthony Gaston.

Gaston and his colleagues have recorded a general decline in the chicks’ growth rate during the same period.

Writing in the journal, The Condor, last year, they point the finger at climate change: “Our results support the idea that mismatching of avian breeding cycles with peaks in food abundance is an important consequence of global climate change.”

September/October 2009

Just how much should we do for species at risk?

By Sharon Oosthoek

Rappelling down an oceanside cliff in the Bay of Fundy to secure peregrine falcon nesting boxes may seem an extreme way to restore an extirpated species.

Ditto herding massive plains bison onto huge cattle trucks and shipping them from Alberta to Saskatchewan, where their like has not been seen in more than 120 years. Not to mention sending captive-bred black-footed ferrets to boot camp to learn the ways of the wild before setting them loose.

The captive-breeding and release program ran from the early 1980s to the mid-90s and brought peregrin falcons back from the brink across the southern part of the country.

In an era where we have altered just about every habitat on earth – whether through climate change, fragmentation or pollution and invasive species – some wildlife experts are starting to argue it’s our responsibility to do whatever it takes to help species at risk.

Yet there are painful decisions to be made: Is there really any point trying to preserve a species when it’s as far gone as, say British Columbia’s 11 remaining spotted owl pairs? How do we decide which species get money and support, and which ones slip away? And given that climate change is affecting some animals’ range so dramatically, is it also up to us to create new habitat for them?

“I think we should make every reasonable effort to conserve every species on the planet,” says Environment Canada research scientist Geoff Holroyd. “I don’t think we should give up on any species.”

Holroyd chairs the peregrine falcon recovery team that brought the birds back to the Bay of Fundy after Canada and the United States dramatically reduced levels of the pesticide DDT. The chemical thins eggshells, killing chicks before they hatch, and was responsible for massive declines in bird populations around the middle of the last century.

The captive-breeding and release program ran from the early 1980s to the mid-90s and brought the birds back from the brink across the southern part of the country. The Committee on the Status of Endangered Wildlife in Canada has since upgraded its assessment of the health of the peregrine falcon’s population twice — from endangered to threatened, and then to special concern.

While there have been other successes since then — the reintroduction swift foxes in the Prairies and elk in central Ontario — conservationists are keenly aware that every time we intervene, we run the risk of making things worse. Ecosystems are, after all, incredibly complex.

“We have to make triage decisions in an informed way,” says Jessica Hellmann, a conservation biologist at the University of Notre Dame in Indiana who has worked extensively in Vancouver Island’s Garry Oak ecosystem. “If we decide to let a species go, is it because we don’t think we can save them? Are 11 pairs of spotted owls enough (to re-establish a population)? Or is it because it’s too expensive, or not important to us? We need more informed deliberation,” she says.

Hellmann and her colleagues have proposed a system for assessing when to help wildlife relocate to places they aren’t currently found. The scientists’ work appeared in a recent issue of the Proceedings of the National Academy of Sciences. In positing a scoring system for weighing scientific and social implications, they hope to help wildlife managers make the best decisions.

They don’t expect their scorecard to eliminate controversy — Hellmann says she and her colleagues often disagree when applying it, even in theoretical situations. But she argues that because climate change is so radically and rapidly altering habitat, we need to consider equally radical answers, such as managed wildlife relocation.

Whereas at one time, animals might have moved on their own as their native range became inhospitable, today cities and farms stand in their way. “These are endangered species and we’re responsible for climate change, and therefore maybe we’re responsible for helping them deal with climate change,” says Hellmann.

But it’s not quite as simple as moving species around, biologists caution.

Consider the case of the propertius duskywing butterfly, native to the Garry oak ecosystem, an area found only on the southeast coast of Vancouver Island and a few nearby southern Gulf Islands. Scientists predict the butterfly’s habitat will get drier and warmer as climate change progresses, making a move north an attractive possibility.

But even if we decided to move this large, dark brown butterfly, it doesn’t have a hope without its host trees, the Garry oaks. And if the Garry oaks are to thrive, there is new evidence that they need a particular type of soil fungus that helps them efficiently absorb nutrients. “So do we move the trees and the fungus too?” asks Hellmann.

It’s so easy to create havoc in ecosystems that deciding to do nothing becomes an attractive option, say conservationists.

“A lot of people say to me, “Let nature run its course. There will be winners and losers. Let it be,’” says Canadian Wildlife Federation conservation researcher Leigh Edgar. “But I think we have a responsibility to fix what we messed up so badly.”

Edgar points to the black-footed ferret — an animal once thought to be unrecoverable — as an example of what happens when we take that responsibility seriously. Early European settlers converted ferrets’ prairie habitat to farmland and then killed their main prey, prairie dogs, en masse in the 1930s, believing the creatures competed with farm animals for land.

Black footed ferret. (Courtesy of the Toronto Zoo)

About the size of a house cat, these sleek animals with black feet, face and tail tip were long believed extinct. But in 1981, a small population was discovered on a ranch in Wyoming. Within a few years canine distemper and sylvatic plague nearly wiped out the entire group. Wildlife biologists brought the remaining 18 into captivity in 1987 to establish breeding and release programs across the United States, and also eventually at the Toronto Zoo.

Only seven of the original 18 had kits, making them the progenitors of the estimated 800 ferrets now living in the wilds of the United States and Mexico. The first Canadian release — scheduled for October in Saskatchewan — will begin with 40 animals.

“The whole world’s population is based on those seven founders,” marvels the Toronto Zoo’s curator of mammals, Maria Franke. While she points to the ferret program as a deliberate and informed intervention, she admits the possibility that it could have unforeseen consequences.

“What if we screw up?” she asks. “Well you have to keep doing it. There are enough recovery programs out there that have shown success and we’ve learned from errors.”

Hellmann agrees, arguing there is no escaping our responsibility for the changes we’ve wrought. “Because of climate change and how it affects biology, we are now literally in the position of playing God. Not doing something has consequences and doing something has consequences,” she says.

Sidebar: Go Forth and Multiply

Twenty-eight years ago, biologists hoping to reintroduce black-footed ferrets to their native North American Prairie had only seven animals on which to base a captive breeding program.

Careful matching was necessary to ensure enough genetic diversity for the species to survive. Even today, each female has three potential suitors based on their genetic profile. If bachelor number one isn’t successful, breeders have bachelors numbers two and three for backup.

“They don’t always get it,” says Maria Franke, curator of mammals at the Toronto Zoo, which runs the only ferret breeding program in Canada. “They sometimes try to breed the female’s head. It’s a bit frustrating. But eventually, one of them gets it.”

In the last 20 years, North America’s six breeding programs have produced 6,500 kits and an estimated 800 ferrets now roam the wilds of the United States and Mexico.

Another 40 are to be reintroduced in October to Grasslands National Park in Saskatchewan.

-SO

Sidebar: Back to the land

Plains bison are once again thundering across Saskatchewan after an absence of more than 120 years.

The animals were wiped out after European settlers took over their habitat for farms and overhunted them for their hides. But 72 bison were trucked into their former range in Grasslands National Park about three years ago from Alberta’s Elk Island National Park.

Wildlife biologists had hoped to see the Saskatchewan population rise to between 300 and 350 bison over the course of five years. But the animals have done remarkably well, producing more calves than expected.

At press time, there were 115 bison with 40 expectant mothers among the herd.

-SO

Lots of Refuge: Private landowners are helping wildlife find food and shelter by nurturing woodlots.

By Sharon Oosthoek

Russell McNally and his wife Marjorie bought their 81-hectare Nova Scotia woodlot about 30 years ago, fully aware that managing it would be no walk in the park. “It was not in good shape,” recalls McNally. “It had been high-graded — they targeted the best trees for lumber and shipbuilding and left the poorest ones.”

The woodlot’s location on the slopes of Nuttby Mountain near Truro, one of the highest points in the province, meant they also had to contend with high winds and heavy snowfall. And so McNally got to work, applying everything he knew about coaxing woodlands back to health. As a forest technician with the provincial Department of Natural Resources, he knew quite a lot.

McNally planted rows of fast-growing red pine on a parcel of abandoned farmland to shelter the surrounding woods from high winds. He thinned damaged and lower value trees, replanting them with more robust species native to Acadian forests. He also built nesting boxes, and created ponds both for wildlife and as insurance against fires.

And when McNally discovered two declining wild apple trees, he nursed them back to health. They reward him with a crop every few years that he shares with foraging deer and partridge.

Nearly three decades later, he and a long list of wildlife — beavers, cougars, rabbits, trout, ducks, hawks, eagles, owls and songbirds — are all enjoying the fruits of his labour.

Anecdotal evidence suggests McNally is on the vanguard of a growing movement among private landowners to rehabilitate woodlots and create a home for wildlife. Whether it’s corridors linking isolated patches of forest or full-on restoration of degraded areas, wildlife is top of mind. And in a province like Nova Scotia, where private individuals own half the land, well-managed woodlots are key to any attempt at habitat restoration.

“A lot more woodlot owners are doing this,” says Jim McCready, program forester with Ottawa-based Trees Canada, a non-profit group that encourages tree planting. “Especially baby boomers moving into rural areas — they are very interested in maintaining their woodlots and planting trees, not only for wildlife, but for water conservation.”

Even in British Columbia, where the vast majority of land is government-owned and forests are usually managed by large companies, there is still room for individuals to protect important habitat.

The threatened phantom orchid for instance, is found only in the Fraser Valley, on Salt Spring Island and Vancouver Island, and mostly on private land, says Zoey Slater, a biologist with the Fraser Valley Conservancy.

Her organization is often called in to assess private properties for threatened species and to recommend ways of protecting them. “It can be good to have a species to rally around,” says Slater. “You may be initially interested in phantom orchids and then discover a rare snail and want to protect it, too.”

Yet responsible reforestation is possible even without the impetus of threatened species.

If your main goal is economic gain, managing your woodlot sustainably still yields both a constant supply of quality trees for logging and habitat for wildlife, says forester Brian McNaughton, who manages a 632-hectare woodlot just outside Williams Lake, B.C.

“I watch the moose cruising around my wetlands. I’ve seen a lot of moose — I’m 54. But boy, my truck pulls over and I have a look every time I see one,” he says.

McNaughton, a consultant to the Federation of B.C. Woodlot Associations, has seen growth spurts in the number of people applying for the province’s unique woodlot licences.

Whereas in other parts of the country woodlots are privately owned, in British Columbia there are nearly 1,000 licence-holders who marry their woodlots to public forests and manage both according to standards set by the province in exchange for logging rights. McNaughton’s own 32-hectare woodlot is attached to 600 hectares of Crown forest; he takes pride in keeping both in top condition.

But the push for well-managed woodlots takes on added significance in more densely populated places like southwestern Ontario, where there is less than five per cent forest cover, composed largely of scattered private woodlots.

Over the years, various tree planting efforts have converted more than 130,000 hectares of abandoned farmland in Canada’s most southerly region into forest, with an equivalent amount of new forest planted on private lands through agreements with landowners, says the Ontario Ministry of Natural Resources.

Farther north, in the transition zone between the Canadian Shield and the St. Lawrence Lowlands, forest regeneration on private and public land has been largely left up to Mother Nature, with some intriguing shifts in wildlife habitat, says Trent University biologist Erica Nol.

The area known as “the land between” stretches across south-central Ontario from Georgian Bay to Kingston and attracts cottagers from across the province. Much of it is former farmland, largely abandoned by the middle of the last century due to its poor, rocky soil.

The forest’s return has led to a crash in populations of some birds, says Nol, an expert in avian and forest ecology. Those species that flourish in open fields and generally shun deep forest – eastern meadowlarks and bobolinks, for example – have left en masse.

“It’s not necessarily a bad thing,” she cautions. “Other species are coming back — species that were there before the land was turned into farms in the mid-1800s.”

Back on Nuttby Mountain, Russell McNally feels fortunate to hear barred owls hooting, and the songs of white-throated sparrow and hermit thrushes. It is “music to one’s ears,” he says.

Today, he is retired and makes his living exclusively from his woodlot, selling lumber and Christmas trees and running a sugar bush operation. But when he cuts, it’s in small parcels and he always leaves a corridor between wooded areas for wildlife. And McNally never touches stream banks where spawning fish depend on the cooling shade of trees.

“It’s not just about growing and cutting wood,” he says. “It’s a balanced approach.”

Sharon Oosthoek is a freelance journalist in Toronto who writes about science and the environment. Her work has appeared in Canadian Geographic, New Scientist, ON Nature and the Globe and Mail.

Woodlots for Wildlife

Many woodlots have had the straightest, healthiest trees taken down for lumber over the decades. Here are some tips for rehabilitating your own property to improve its value to you and animals both.

Don’t go with the first outfit that offers to cut your trees. “If someone knocks on your door and says, ‘I’ll give you $50,000 for your trees,’ and you’re not doing so well, you’re going to take the $50,000. Unfortunately, a lot of forest companies don’t do it sustainably,” warns Trent University biologist Erica Nol, an expert in forest ecology. Get expert advice on your woodlot’s worth from your local conservation authority, an independent forestry consultant, woodlot association or provincial department of natural resources or forest management.

Consider planting fast-growing native species to provide a wildlife corridor between patches of woodland. Eventually, a more mixed forest will establish itself, but in the meantime, you will have provided crucial shelter for wildlife needing to move from one patch of trees to the next.

Never log along a stream. Shade from trees keeps fish-spawning habitat cool and provides cover for other animals as they drink.

Investigate programs designed to alleviate — and sometimes completely cover — the cost of woodlot rehabilitation. Again, conservation authorities, woodlot associations and the provincial government are fonts of knowledge.

Look into obtaining Forest Stewardship Council certification. Trees from FSC woodlots can fetch a premium price because they are certified by a reputable third party as coming from a sustainably managed operation. Some woodlot associations may help defray the cost of certification.

-SO

Black Bears on the Bruce

Genetic analysis of the black bears living on Ontario’s Bruce Peninsula shows they are an isolated population that rarely mates with bears across Georgian Bay, making their continued existence a precarious thing. An estimated 200 to 500 bears roam the heavily forested peninsula, but development along the bay’s south shore mostly precludes them from breeding with bears on the other side.

“With a small population of any organism — and their numbers are probably closer to the lower end of the 200 to 500 range — there is always the possibility of the population disappearing,” says Ministry of Natural Resources bear expert Martyn Obbard.

He suspects a major forest fire on the peninsula around 1900 reduced the bears’ numbers dramatically and that only a few survived to replenish the population. But with their route off the peninsula barred by farms, resorts and cottages along the bay’s south shore, there has been little opportunity for mixing up the gene pool over the last century.

Obbard says while it’s not realistic to reforest the area, maintaining existing habitat on the peninsula is crucial to the black bears’ survival. As development pressure increases, Obbard urges landowners to be stewards of their forests, cutting down as little as possible and retaining the mature beech and oak trees whose nuts are an important food for bears.

“The work we’ve done suggests if there aren’t dramatic changes in habitat, the population can persist,” he says.

-SO