Cuyahoga Valley National Park Struggles With the Effects of Climate Change
Conservation has been the guiding principle of America’s national parks. But climate change is undermining that mission. The National Park Service says ecological changes are happening so fast and on so many fronts, park rangers may need to choose what to save and what to let go.
“The ‘resist' and the ‘direct’ part of it are more like my nature. I like to try to fight back," said Chris Davis, a plant and supervisory ecologist at the Cuyahoga Valley National Park (CVNP), the only national park in Ohio. “The ‘accept’ is more like, I guess, to me, it’s disappointing, but at the same time, it’s just practical.”
Davis and I met at the park on a recent late summer day to talk about the new guidance and how it may be applied here. He said “acceptance” will be the de facto approach of many park managers as a result of limited resources and a formidable foe.
“I mean, national parks, they’re so huge. There’s no way we can actively fight climate change, it’s a global phenomenon," Davis said.
As for “resist,” as Davis suggested, that’s baked into the Cuyahoga Valley National Park’s DNA. Since its inception in 1974, park rangers like Josh Bates, CVNP's parks volunteer program manager, have labored to turn old fields back into forest, planting native trees like red oak and hickory and ripping out non-native, invasive plants. Bates says they’ve got a knack for showing up just about everywhere, crowding out native species.
“They seem to adapt to anything, so, poor sunlight, they’ll still figure out how to grow. Poor soil, that’s all right," Bates said.
Hotter temperatures? Invasive species can adapt to them, too. As summers get warmer and longer due to climate change, it will be harder to hold the line against these invaders.
Some parks are already acknowledging the inevitable. At Acadia National Park in Maine, where eight of its 10 most common native trees are expected to diminish in the coming decades, park managers are considering assisted migration—planting more southerly tree species—to avoid a forest full of invasive shrubs.
Davis said he’s got a tree in mind if, or when, the Cuyahoga Valley National Park needs to take similar action. It’s black locust.
“So, black locust here, historically, we’ve considered it invasive. It comes in, and it will take over a whole field," Davis said. "But it is naturally present just south of here, like in southern Ohio and Kentucky. So, in the past we’ve been fighting that tree in some sites. And now we’re trying to, like, not so much, because it’s probably on its way."
Assisted migration comes under the category of “directing” change in the “resist, accept, direct” guidance. Here, park managers shepherd a landscape toward a new ecosystem that is presumably more stable, more adaptable and more desirable than it would be if left alone.
Davis is taking this approach with respect to the biggest climate challenge facing the Cuyahoga Valley National Park: more rain.
“So, over the last 30 years, 40 years, precipitation has increased about a little over a tenth of an inch a year," he said. "So, we’re getting inches, now, more rain than we used to get.”
Seven inches more since 1960, according to the U.S. Army Corps of Engineers. That, along with more development in the valley, has led to more runoff. It’s washing away the river’s banks, making them steeper and more attractive to the invasive plants park officials are trying to get rid of, like Japanese knotweed.
Davis said knotweed covers 40 percent of the riverbanks along the park’s 26 miles of Cuyahoga River.
A kayaker plying the Cuyahoga River paddes past a steep riverbank covered in Japanese knotweed, a non-native invasive species. The herbacious perennial was introduced from East Asia in the 1800s to stabilize river banks. [ Cuyahoga Valley National Park]
To accommodate the extra rain and runoff and keep the river’s banks from eroding, Davis and the Army Corps want to make the river longer. They want to add a bend to the river, and restore another one that engineers wiped out when the Vaughn Road Bridge in Brecksville was built in 1967.
Standing on the east bank of the river, the bridge at our backs, Davis told me to look upriver.
“So, the river, you can see where it’s bending toward us right now. Before this bridge was put in, this went waaaay down and there was a huge meander bend that would have been here. When they put in that bridge, sixteen hundred to eighteen hundred linear feet was just ... cut off!" Davis said, clapping his hands together for emphasis.
Cuyahoga Valley National Park ecologist Chris Davis points upriver to a bend in the Cuyahoga River that was created by engineers building the Vaughn Road bridge. The river used to continue farther south before making a meander. The cutoff eliminated 1,600 to 1,800 linear feet of the river, causing greater erosion due to runoff. [Cami Miller]
The two new river bends would restore 1,200 linear feet to the river, just shy of a quarter mile. Davis said it will help with runoff and erosion, but just a little.
He said the Army Corps’ studies show they really should be adding five extra bends in the river totaling 2,500 linear feet if they want to address current flow conditions, and six bends of 3,000 feet if they want to prepare the valley for a warmer, wetter future.
The U.S. Army Corps of Engineers has suggested lengthening six bends in the Cuyahoga River to meet current and anticipated future precipitation conditions in the Cuyahoga Valley National Park. The current plan is to add just two bends, Nos. 2 and 6 in the image, above. The Army Corps' hydrolic studies suggest bend numbers 2, 3, 4, 5 and 6 would be needed just to meet current flow conditions.
"We've went from 'over' restoring the river by adding 3,000 feet to underbuilding it by adding only 1,200 feet," Davis said in an email. "It's still a good, worthwhile project; it just won't have the immediate benefits for which we initially hoped."
He said they just can’t afford it.
It’s just one of the many harsh realities that park managers are facing as they reconcile themselves to their new roles steering America’s heritage landscapes toward an unknown future.
Ideastream intern Isaac Haught assisted in reporting this story.
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