Fire, bison, humans all elements to habitat restoration
| Posted: Thursday, Feb 17, 2011 06:00 am
One of the goals of the current Banff National Park Management Plan is to bring Plains Bison back to the northeastern valleys of Banff National Park.
While the goal may seem like a new idea – and not without controversy – it is not a new objective for Parks Canada.
Parks Canada reached that conclusion as part of a long series of questions, experiments and even missteps as officials worked towards restoring habitat in the Banff-Bow Valley region, according to Cliff White, research director, Canadian Rockies Bison Initiative and former environmental science manager with Banff National Park, during his presentation: Bison, Beaver, Aspen, Caribou: A Holistic Perspective on Canadian Rockies Ecosystem Restoration. The talk was part of the How Wildsmart Are You? Speakers Series at the Canmore Collegiate High School Theatre Jan. 31.
Habitat restoration is a complex and challenging endeavour that is attempting to undo well over a century of dramatic change brought about as the valley shifted from wilderness with a low population of First Nations people to industrialization with the arrival of the railroad, altering what had evolved over 10,000 years.
Repairing that damage, White said, requires a holistic approach that combines scientific and traditional knowledge to understand the variability and the characteristics of the ecosystem while working with stakeholders to make it happen politically.
The philosophy of managing the park and its landscapes has changed since it was founded in the 1880s. Then, it was a means to help pay for railroad construction and as a place that accepted resource development, such as logging and mining, within park boundaries. In the 1950s and ‘60s, Parks took a hands-off approach of natural regulation that strived to leave the wilderness alone to regulate itself. The last two decades have seen a new approach.
“In the last 20 years or so there has been more of a variability idea that says probably the best thing to do is to think how did this ecosystem evolve and how did it evolve over the past 10,000 years and take some parts of that into the future,” White said.
The outset of that approach was a question of why the Cascade Valley was such good grizzly bear habitat. From that question came Banff National Park’s first fire study that demonstrated that the best bear habitat in the Cascade Valley was where two fires – one in 1889 and the other in 1914 – overlapped.
From that led to an exploration of fire and why it was necessary. That, in turn, led Parks Canada to light its first prescribed fires in the early 1980s in an attempt to restore ailing aspen stands that had been overgrazed by elk.
But political turmoil, including a prescribed fire got out of hand and approached Banff, increasing development in Banff townsite and increasing wildlife mortality, including the highway deaths of wolves that had just returned to the valley, led to a period in 1993 when White said Banff National Park was a place that did not know where to go.
“It got to the point where we realized we’ve got a big problem,” White said.
The solution to that problem came from the 1994-1996 Banff-Bow Valley Study and the 1997 Banff National Park Management Plan: a document White said was the first to prescribe what was needed in Banff for habitat restoration.
One of the first tasks from that plan was to restore predator-prey relationships and regenerate aspen stands. With that came a renewed look at how First Nations interacted with the landscape and a study by a top American ecologist Charles Kay and White that analyzed early habitation sites and the reports of explorers to create a record of what wildlife had been found in the central Rockies preceding railway construction.
“And the main point we brought out was that this was largely a bison system in the early 1800s, to bison being knocked out of the system by 1860 or so and elk beginning to dominate the system,” White said.
Along with that change in systems came an exclusion of First Nations people from the Bow Valley region and a reduction in the amount of fire.
White pointed out that many people believe the arrival of the railroad coincided with a greater number of fires in the Bow Valley, but in fact more fires burned in the decades preceding the arrival of the construction crews and the cinder belching locomotives.
“The amount of burning in 1880 was already going down and then it dropped dramatically by 1940,” he said, adding the Banff region is in a lightning shadow.
West of the Great Divide sees about 100 times more lighting strikes than Banff, however, Banff historically saw more fires.
The missing link was an ongoing regime of human-lit fires ignited in early spring that White said created the diversity in Banff and the Bow Valley of old-growth trees in back valleys and young growth and aspen and grasslands in the dry valley bottoms.
And one of the reasons First Nations lit the fires, along with regenerating plant species and keeping trails open, was to keep bison in the valley to stock their larder with a convenient, secure and high-value food source.
“Possibly one thing they were doing was burning the valley bottoms to lure in bison from the open plains. You burn off the dead grass and get fresh green grass and bison will come into these valleys and move way up into the valley and if you can lure some bison up the Bow Valley near Banff, if you can get them to Castle, that is like putting them in a fridge,” White said.
Without bison, fire and First Nations and with the security the park provided, the number of elk rose to 1,000 by 1990 and as they foraged in the valley bottoms, aspen and willow declined as did the moose and beaver that relied on those.
With such a large number of elk, a species White called “high-octane fuel” for wolves, the number of wolves jumped as well and where they once primarily stayed in the Bow Valley, began to move into more remote valleys, such as the Pipestone, where they came into contact with the roughly 20 individuals of Banff’s herd of caribou. By 1999 the number had dropped with the last five caribou killed in an avalanche on Mt. Hector in 2009.
“The question then becomes what can we do to fix this and ensure the system remains a low elk and low wolf system and bison are the first place to look,” White said. “Historically, (it) was really unusual to have this many elk in the system. Historically, this system was dominated by bison.”