Rainforest Wolves

Rainforest Wolves

Matt Jackson

2002

Abstract

Focuses on research on the genetic characteristics of coastal wolves in British Columbia. Theories on the evolution of coastal wolves; Physical and behavioral differences of coastal wolves from continental wolves; Concerns regarding the impact of logging on coastal wolf habitat; Effect of the research on wildlife conservation.

In the heart of British Columbia's Great Bear Rainforest roams the elusive coastal wolf, an animal with genetic characteristics uniquely different from those of its continental kin. What this new discovery will mean for conservation on the central coast is the subject of an intense and ongoing debate.

We had just forded halfway across the mouth of a flooding tidal river on British Columbia's central coast, chest-high in water, when the misty air around us suddenly erupted in wolf song. It was not the beautiful and mournful howling you sometimes hear while sitting around a campfire in the backcountry, but rather an agitated barking intended to let us, as intruders, know that we should keep our distance. So we stopped, frozen in the middle of the powerful current, wondering exactly what we should do next.

Then we saw Chris Darimont, a wildlife biologist working on B.C.'s five-year coastal wolf research project, waving frantically at us from the opposite side of the river. "Look, he wants us to cross back to the other side," said Karen McAllister, a member of B.C.'s Raincoast Conservation Society, the principal sponsor of the study. We needed no further encouragement. The two of us executed an abrupt turn and started back across the river to where, we hoped, we would no longer pose a threat to the pack's young pups.

Earlier in the summer, the sailboat Nawalak and its crew of naturalists, biologists, and First Nations researchers had, by some fluke, stumbled onto this magical inlet. Tired after a day of bushwhacking and following game trails in search of wolf scat, they were suddenly jolted awake when an adult wolf and five pups appeared along the shore less than 30 metres from the boat. They exchanged wolf calls with the pack, then went ashore the next day for a closer look at the estuary. Once on shore, they found well-defined wolf trails criss-crossing the tidal flats, dozens of headless salmon along the riverbanks, and a plethora of other wolf signs.

Oh, and the scat--endless bags of it, all to be carefully labelled, preserved, and shipped down to the Conservation Genetics Laboratory at California's UCLA. Once at the lab, a team of geneticists apply cutting-edge technology to examine the mitochondrial DNA sequences in live cells pulled from the waste. Scat has only a few stray cells, scraped from the intestinal tracts of wolves as they digest their food. Fortunately, this new technology permits scientists to pull DNA from the scat and has now provided convincing evidence that coastal wolves have unique genetic characteristics not found in their continental brethren.

This is how it works. From the wolf research that has been conducted to date, roughly 35 different DNA haplotypes have been identified in global wolf populations. A haplotype is best described as a miniature recipe, and hundreds of these miniature recipes (or sequences) exist on even a small section of the DNA strand. To distinguish variation, geneticists are looking for haplotypes that differ from those found in sequences from other wolf populations. Of course, some haplotypes are shared by all populations of a species, while others exist in only a few different populations. Finally, there are those haplotypes that are endemic or rare and can be found only in specific populations.

"What's exciting about coastal wolves is that we've found four or five haplotypes that haven't been identified anywhere else on the continent," says Darimont. This doesn't mean that these haplotypes don't exist in other wolf populations or that all coastal wolves share these same genetic characteristics; however, it is entirely possible that wolves living on the West Coast are unique and have been evolving in isolation over several millennia.

This is what scientists refer to as evolutionary potential--subtle differences in the genes that may allow wolves on the coast to continue evolving along different lines than wolves living elsewhere. In other words, wolves evolving in relative isolation on the coast may have the genetic tools to better adapt to changing conditions over time--conditions specific to the West Coast rainforest.

Knowing this, it quickly becomes clear that Darimont isn't collecting just scat, but little bundles of information. Over two field seasons, he and his team have found more than 1,600 of these information bundies--combing some 60,000 square kilometres of the Great Bear Rainforest in the process. Apart from genetic identification, Darimont hopes to use the data collected to learn more about what coastal wolves eat at different times of the year and the span of their home ranges, as well as how far young wolves disperse from their pack.

One of the newest theories of the evolution of coastal wolves springs from the research of evolutionary biologists Tom Reimchen and Ashley Byun from the University of Victoria. Since 1985, Reimchen's molecular DNA work has examined various species on the West Coast, including black bears, weasels, martens, and sticklebacks. Along the way, he has discovered that the coastal versions of all these animals have evolved along a very different lineage than that of their counterparts in the interior of the continent. "Across North America, there are two distinct lineages of black bears," says Reimchen. "All coastal bears have the same ancestor, while continental black bears have a different ancestor."

Before the last ice age, Reimchen has hypothesized, coastal animals existed in a series of ice-free glacial refuges along the West Coast. Through his research, Reimchen has managed to trace time back some 360,000 years, to the period when a genetic split in black bears occurred. Did coastal wolves exist on these refuges as well? Or did they recolonize the West Coast after the ice retreated a mere 8,000 years ago, as has always been believed? Although wolves require different prey species and a much larger territory to survive than do black bears, it is now believed that several large, interconnected refuges may have provided this. If so, coastal wolves may have been evolving in relative isolation for a lot longer than previously thought.

So what is the actual meaning of all this minute information coded in the genes? Are coastal wolves any different from those wolves that have evolved inland? As Darimont freely admits, it's much too early to speculate, although there do appear to be subtle physical and behavioural differences that may have evolved because of the wolves' marine rainforest habitat. Wolves on the coast, for example, are generally smaller than continental wolves, perhaps an adaptation to the thick foliage they have to move through or maybe because their primary prey, Sitka black-tailed deer, are much smaller than the prey that wolves living elsewhere have to contend with. The hair of coastal wolves also appears to be coarser and better at shedding water, perhaps an adaptation to the heavy rainfall on the West Coast.

Apart from appearance, coastal wolves have also adapted from a behavioural standpoint. Initial field observations indicate that they range over vast territories and sometimes--perhaps often--are forced to swim across sizable saltwater channels to disperse. Darimont's team has collected scat samples from even the smallest and most remote islands, including the Estevan group and Dundas Island, the latter of which is more than 10 kilometres from other islands more closely linked to the mainland. It was also recently discovered in a similar study that a radio-collared wolf on the Alaska Panhandle swam at least 10 kilometres across Clarence Strait, from one island to another....

Another behavourial difference on the West Coast, apparently relates to the diet of coastal wolves. While it's true that Sitka black-tailed deer are their staple food source year-round, it has been thought for some time that salmon are also important to their diet. How important, nobody knew. Recent evidence pulled from scat samples suggests that at least 25 percent of a wolf's diet in autumn is protein-rich salmon, though more recent field observations suggest that certain packs may depend even more heavily on salmon for food. "We watched three packs this fall sitting on salmon rivers day and night, eating salmon almost exclusively," says Ian McAllister of the Rainforest Conservation Society. "Their reliance on salmon is obviously far greater than we originally ever would have thought."

....[A]s industrial-scale logging creeps ever closer, this knowledge couldn't come at a better time.

The roar of bulldozers and graders shatters the early morning calm over James Bay, a sheltered inlet on the southeast side of Pooley Island. One after another, we rise from deep slumber to find a road-building crew hard at work, preparing the southern end of Pooley for industrial-style clear-cutting. There's a sombre mood on board as we eat breakfast, don our rain gear, and set off toward the James Creek estuary in search of a family of wolves that has been using this land for at least 10 years. In the month since the road building started, there has been no sign of adults or pups anywhere nearby.

It is this conflict--the business of logging versus the business of trying to protect an intact ecosystem--that in recent months has caused an intense battle to erupt over Pooley. Western Forest Products, the company with rights to the island's timber, has been approached by environmental factions arguing that scientific data show Pooley to be of exceptionally high value to both deer and wolves. Geographic Information Systems (GIS) modelling has identified huge tracts of land that provide excellent Sitka deer habitat, and field observers have seen reproducing wolf packs on the island every year for the past decade.

As the battle over Pooley reached a climax, Western Forest Products finally agreed to spare part of the island's northeast quarter. There are still plans to log the other parts, however, with little evidence as to how this will affect the balance of the overall ecosystem. Will wolves continue to use the island for raising pups? More importantly, will its roads bring other human-related activities into a previously inaccessible region, as has been the case in southeast Alaska, where annual wolf mortalities have reached a staggering 30 to 40 percent?

Also important to consider will be how clear-cutting could affect deer populations on the island. A few years back, protecting old-growth forest for the sake of deer might have seemed absurd. It was common knowledge that cut blocks were of benefit to deer because plenty of forage sprouts shortly after the timber has been taken out. Recent evidence, however, indicates that this might not be true. "We're now learning that clear-cuts are like giving deer a severance package," says Darimont. "At first, they're getting a smorgasbord, but in the long run, they're getting a raw deal. That clear-cuts are good for deer is dogma, and it's completely inaccurate."

....Spaced much closer together, second-growth forest creates a closed canopy, effectively blocking out the sun from maintaining understorey vegetation on which deer depend for food.

"We call this succession debt," says Alaska Department of Fish and Game biologist Dave Pearson, who has studied wolf-deer systems on the Alaska Panhandle for several years. "Clear-cut logging appears to set in motion a pattern of change that upsets predator-prey dynamics several decades into the future." For proof, Pearson offers data from his extensive radio-telemetry work, which found that old-growth forest supports 40 to 50 deer per square mile, while second-growth forest 40 years of age will support roughly three deer per square mile. From this, it doesn't take much to do the math: fewer deer inevitably means fewer wolves.

We never did locate our family of wolves that morning on Pooley Island--not a single scat, hairball, or paw print to be found. But that doesn't mean they won't be back. We can only hope that as industrial logging inches farther north along the coast, timber executives and environmentalists can find some common ground. "There seems to be this convergence of need and greed," says Darimont. "If we don't do something to prevent it, wildlife and industrial logging will collide head-on." If that happens, the secrets of the elusive coastal wolf may never be known. And we will all be the poorer for it.

INCLUDES

Five color photos