On the western edge of Rocky Mountain National Park lies the Kawuneeche Valley, nestled between the Never Summer mountains and the Front Range. Formed by the Colorado River Glacier and historically a home for a diverse spectacle of life, the basin was once a vibrant, wetland-rich ecosystem.
Today, the Kawuneeche — which means the valley of the coyote in the Arapaho language — is experiencing a significant loss of biodiversity.
The National Park Service, working in tandem with a coalition of conservation partners, has set out to reverse that trend. To do so is a complex process that involves three major pieces: beavers, moose, and willow.
And restoration must account, too, for the human presence at RMNP, the extirpation of the ecosystem’s most important predator, and the ongoing and accelerating impacts of climate change.
The road to restoration in the Kawuneeche is the tale of a century. During that time, the combination of human infrastructure, predator absence, herbivore overpopulation, and Earth’s changing atmosphere have transformed the once-thriving valley into a more arid environment.
An Ecosystem in Decline
Glaciers formed the Kawuneeche Valley during the planet’s last Ice Age. Those glaciers eventually began to melt, forming moraines – deposits of debris, including rocks, carried by the glaciers – there and in other places at RMNP.
Today, this high altitude geologic depression is a visible reminder of the iconic waterway that has its start nearby: the Colorado River.
The Kawuneeche “is part of the headwaters of the Colorado River,” said Kimberly Tekavec, a water protection specialist with Northern Water during a media tour at RMNP in October. “[It] was once a very significant wetland spanning eight miles long, over half mile and just over the last 100 years, and then, really, like exponentially, in the last 30 to 50 years, the system has just been in decline.”
The decline is especially obvious when measured by the loss of beaver.
In 1940, there were at least 200 beaver colonies and at least 1,800 individual beavers in Rocky Mountain National Park, according to a 1947 survey.
By 2009, the dam-building mammal was found at only 17% of the sites it had historically occupied. More recently, RMNP staff estimated that there are 94% fewer beaver ponds in the Kawuneeche Valley since 1953. Their loss has driven a disappearance of natural ponds and an absence of functioning wetlands. In fact, according to the Park Service, the Kawuneeche now “functions more like an elk-grassland ecosystem than a beaver-willow wetland ecosystem.”
The situation is now dire. “[T]ributaries that used to just be pond complexes and big wetland complexes are now supporting in size channels, and those wetlands have dried up and are kind of dying,” Jeremy Shaw, a wetland ecologist at Colorado State University and a member of the research team managing the restoration project, said.
But what explains the beaver’s plight in the Kawuneeche?
The state’s history of beaver trapping for furs largely ended in the 19th century. So hunting of the semi-aquatic rodents is not a contemporary driver of their precarious place in contemporary Western Slope ecosystems.
The answer, instead, is in the shrubs.
“Willow are a critical food and dam building material for beaver, whose dams cause the over-bank flooding necessary to create and maintain willow habitat and riparian wetland complexes,” according to a National Park Service website. Beavers rely on thickets of the plant to build their home structures. The loss of the willows has been dramatic, with the number of tall willows falling by 77% since 1999, the agency says.
The loss of willows has also driven the loss of wetlands. “We get into this feedback loop where we lost the beaver, or functionally lost the beaver that allowed the valley to basically dry up to some degree,” Shaw explained. “Because the beaver dams . . . were not being maintained. They breached, the channels [that had previously been wide and shallow were] cut down, the wetlands dried up.”
Those events have, in turn, adversely impacted other wildlife. “The dieback of riparian willows…affects many species, especially songbirds,” according to a scientific paper published by Colorado State University scientists in 2014. “[W]illow stands with stems averaging 0.66 m in height support half the number of avian species and individuals as stands averaging 1.5 m tall.”
One principal cause of the willow decline, and therefore the loss of beaver and other native animal populations, are the moose that are now ubiquitous in the Kawuneeche.
Thought to have occasionally wandered into the state from Wyoming, but never taking up permanent residence in the Centennial State, Alces alces shirasi became denizens of RMNP after Colorado Parks and Wildlife introduced them in 1978 and 1979.
The large mammals, which are part of the deer family, consume huge quantities of riparian vegetation. Willows are the bulwark of their diet, constituting about 91% of their summer diet.
And the population of moose in RMNP has exploded. An aerial survey in 2019-2020 recorded 149 moose in the park’s survey area, though the total population could be higher and is growing at about a 5% rate every year. Each adult moose can eat up to 60 pounds of plants daily, which starkly limits the capacity of willow thickets to regenerate and, therefore, also restrains available beaver habitat.
The role of predators
Historically, apex predators like gray wolves and grizzly bears regulated herbivore populations. Wolves were eradicated from Colorado by the mid-20th century. Though recently reintroduced at the direction of the state’s electorate, Canis lupus has not yet reestablished a population inside RMNP.
Wolves probably do prey on older or arthritic moose, concluded one 2022 study, but “prey population growth rates tend to be less impacted by predation when predators exhibit selection for juveniles and senescent adults because those age-classes have lower reproductive values than prime-aged adults.” That indicates the likely future presence of wolves at RMNP may not solve the park’s moose overpopulation problem.
On the other hand, wolves could help limit the population of another ungulate grazer at the preserve: elk. Those ungulates favor aspen, but they will also voraciously consume willows. Elk “also suppress[]the growth of willow plants, both in height and areal cover, and tall willow stands were being converted to short willow,” said a U.S. Geological Survey study published in 2015 that studied the animal’s impact on Rocky Mountain National Park.
Largely eliminated from the Colorado Rockies by the late 19th century, elk from Yellowstone National Park were transplanted to the region during 1913-1914. Now they number about 280,000 statewide, according to CPW, and the winter population of elk at RMNP is probably between 600-800 animals. Few of those wapiti spend the cold season in the Kawuneeche, likely due to snow depth, but during the summer Cervus elaphus does mostly linger at high elevation or in the valley.
While there is an ongoing robust scientific debate about exactly how much wolves contribute to ecological recovery, it is evident that elk populations in Yellowstone decreased after the return of wolves to that ecosystem, which in turn contributed to the recovery of riparian vegetation. RMNP officials do not expect that the return of wolves to RMNP, by itself, will be enough to restore the ecology of the Kawuneeche Valley.
“The return of wolves alone is unlikely to restore healthy, functional wetland processes in RMNP,” an NPS website proclaims.
The state’s last grizzly bear was killed in 1979. And bears are not especially successful predators of adult moose and elk, though they can and do attack calves.
The presence of moose and elk, and the absence of beaver, wolves, and grizzly bears during recent decades, is not the only cause of the Kawuneeche’s condition. Water diversions from the upper Colorado River, wildfire, and climate change also contribute to the problem.
Completed in 1936, the 15-mile-long Grand Ditch collects water and moves it to the Cache la Poudre River instead of allowing it to flow through the Kawuneeche. The diversion removes between 20-40% of the Colorado River Basin’s flow from the area.
“Eleven headwater tributaries of the Colorado River are intercepted by the ditch between May and September every year,” NPS notes, and “[t]he ecological impacts of the Grand Ditch are significant.” They include loss of about half the seasonal flooding that has historically helped to feed Kawuneeche wetlands and riparian plant life, including willows, and damage to unique peat soils in the area.
The Grand Ditch was the source of major damage to the Kawuneeche in May 2003, when a bank breach caused debris to flow into the upper part of the valley. That incident damaged about 1.5 miles of riparian, stream, upland, and wetland habitat and altered hydrological functions at and below Lulu Creek and the Colorado River headwaters.
The East Troublesome Fire
The East Troublesome Fire of 2020 added urgency to the restoration of the Kawuneeche Valley. That fire, one of the largest in Colorado’s history, burned more than 27 square miles on the west side of RMNP and destroyed numerous willows there. The decline in the trough’s wetlands helped make that decimation possible.
As for the ongoing alteration of Earth’s climate, at RMNP the warming of the atmosphere has pushed average annual temperatures up by about 3.4 degrees Fahrenheit during the past century. The increase is causing earlier snowmelt, driving entry of invasive species that compete with native plants, and drying out soils.
“In the short term, melting permafrost may supplement stream flows during dry periods. Over time, this ‘stored water’ will diminish and streams will dry,” the park service said in a recent survey of likely climate change impacts to RMNP. “A drier climate will decrease or even eliminate some wetlands.”
Because the Kawuneeche is becoming increasingly arid, even the prospect of climate change-driven increases in precipitation will not necessarily be helpful in restoring beaver habitat and, therefore, wetlands.
“That is increasing the evaporative demand and the transpiration demand that the vegetation uses,” Shaw said. “Whatever water comes into the system, more of it gets evaporated out and less is available to support wetlands and the river and flow downstream.”
The Restoration Plan
To address these interconnected challenges, NPS and various partners established the Kawuneeche Valley Restoration Collaborative. The collaboration, which involves the U.S. Department of Agriculture’s Forest Service, Grand County, Northern Water, and the town of Grand Lake, aims to work comprehensively to restore the Kawuneeche’s ecology.
“KVRC is focused on long-term planning to strengthen the Valley’s resilience by bringing together experts who are deeply knowledgeable about and invested in the health of the Kawuneeche Valley’s environment,” the cooperative’s website announces.
The coalition began on-site work to revitalize the valley earlier this autumn. Central to the organization’s strategy is encouragement of beavers to return. To facilitate that result, KVRC has begun to build beaver dam analogs in the Kawuneeche. The BDAs are designed to mimic the effects of beaver dams and duplicate their ecological benefits. They slow water flow, promote sediment deposition, and help raise the water table, which create favorable conditions for willow growth and biodiversity.
During a presentation several weeks ago to media representatives on site in the valley, KVRC representatives and RMNP staff showed off several BDAs.
“Beaver Creek is the first project we’ve implemented here, and we very much view that as a pilot site,” Shaw said, referring to the location of one of the structures installed in the Kawuneeche. “And we’re doing a lot of things that are practiced in other places, but . . . we’re not trying to predict what will happen. We have ideas and hypotheses, but we’re monitoring and collecting data to learn from it and then adapt and improve and then apply those lessons elsewhere.”
Another undertaking has been to install fencing to protect surviving willows from moose and elk. During the October media tour construction was underway on one stretch. Each of the planned fenced-in zones will be 30-40 acres in size. Once in place, the fencing is expected to remain for about 20 years. “One of the things that’s missing . . . is a seed source for willow,” one unidentified representative of KVRC said.
“We’re hoping that the willows and the exclosures now will produce this seed. And one thing that we’ve seen in Moraine Park, where we have had exclosures for the past 15 years, [is that] beavers have come back in and they’ve actually linked the area between the exclosures, so they’ve re-wedded the area between them.”
KVRC has raised at least $3 million to help with the restoration project. No funds are allocated to it in the Park Service’s budget.
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