Sharon Writes

Canadian Wildlife

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.

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.

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