The Five Days That Changed the Way I Think About Ecology

“Put on your helmet,” the boatman said to me. Moments earlier, we stood on the jagged rocks at the edge of the Yampa River, watching a party of rafters tumble across Warm Springs Rapid. One by one, their rafts were tossed through the air by green-brown waves that would have looked at home on the Pacific. One of boaters lost an oar as I watched, scrambled for it and barely recovered in time to dodge a monstrous hole–a current where the river flows so forcefully over a submerged boulder that it pours into itself, like faucet water plunging into a full sink. Holes can flip heavy rafts and drown hapless passengers. We were about to traverse a rapid full of them to finish our mission.

It sounded simple. Help pull some invasive weeds from the river banks. Dan Chure, the park paleontologist at Dinosaur National Monument, had emailed Elliott Smith, Marie Jimenez and me–his summer assistants–asking if we wanted to help out the Monument’s invasive plant management program on a river trip. We all volunteered, of course, before we had even arrived at Dinosaur or met each other. Who would turn down a river trip through one of the most beautiful of America’s national monuments?

The equipment list filled a printed page. I was already on the road to Dinosaur when I received it, and I stopped at an REI near Olympia, Washington to pick up everything I was missing. Adequate rain gear was vehemently emphasized, with a special note saying they wouldn’t take anyone who didn’t have proper attire. This included synthetics and wools (apparently cotton is a recipe for hypothermia on a trip like this), rain pants and jacket, hats for both cold and sun, all of the standard camping gear, shoes for water, shoes for work, watch, sunglasses, and a good travel mug. For hot coffee, of course.

The gear had to be loaded into dry bags, which keep their contents waterproof by a system of tight packing, folding and clipping. The dry bags went into Marie’s Toyota, and we drove to the employee housing area on the Colorado side of the park, near the town of Dinosaur (named after the monument). There, the gear was hauled to the front lawn of the Resource Management building, where we met Patrick Fleming, Peter Williams and Tamara Naumann.

Peter and Tamara moved to Dinosaur together over two decades ago, when Tamara was offered a job here as park botanist. She initiated the Weed Warriors program to tackle invasive plants like tamarisk, also called salt cedar, which turns cobbled river beds where native fish spawn into impenetrable sand bars neither fish nor boater can use. The trees change the entire ecology of rivers whose banks they invade, and they’ve become a hot issue throughout the American Southwest. The tools at the disposal of the Weed Warriors include shovels, saws, a tripod pulley system built by a volunteer, occasional herbicides, and thousands of tiny brown beetles.

The humble tamarisk beetle has been an enormous asset to Dinosaur’s weed management program but a headache for the Department of the Interior. As Tamara explained, after twenty plus years of research into using them as a biological agent against tamarisk, they were deemed one of the safest, lowest-risk introductions of a predator species to combat an invasive plant ever attempted. Extreme measures were taken to prevent a cane toad scenario; the beetles were tested in multiple long-term studies to ensure they would be effective against tamarisk and wouldn’t turn against any native species. At the end of two decades of controlled trials, it was evident that the little brown bugs enjoyed only one activity with single-minded abandon: devouring tamarisk.

Unfortunately, by the time the beetles were ready, tamarisk had become so entrenched in the ecosystem that native birds–endangered southwestern willow flycatchers in particular–were starting to call them home. This is where the headache begins. Willow flycatchers, as the name implies, originally nested in the native willows that line many a Southwestern river bank. As tamarisk took over, the birds began to prefer the structure of its branches, hatching their young under its needly outer foliage even though they still needed native plants to host their prey.

That outer foliage is the first thing to go when tamarisk beetles infest a tree. It’s easy to see where the controversy built from here: fish fans and boaters found themselves pitted against birders who decried the fate of hatchlings now roasting under bare tamarisk branches. In the ensuing debates, the Department of the Interior barred the beetles from additional releases, even in places where the willow flycatcher doesn’t live, like Dinosaur National Monument.

My boatman, Peter, introduced me to my first tamarisk beetle. After inspecting one of the small, thickly-branched trees, he turned to me, holding out his hand. His palm was calloused from the countless oars, shovels, saws and ropes that have been his weapons against tamarisk for years. Across his palm, so small it surprised me, crawled a simple brown bug.

Across his palm, so small it surprised me, crawled a simple brown bug. “They get bigger,” he said with pride. “A few millimeters bigger.”

“They get bigger,” he said with pride. “A few millimeters bigger.” He told me how he’d given the first batch of beetles a sprig of tamarisk to munch on before they were released, and when it came time to let them loose, he discovered the sprig was the perfect tool for placing them on trees. All he had to do was set it at the base of a tree and watch as the beetles climbed and flew into the branches of their new home and soon-to-be victim.

There are countless spots in Dinosaur where the beetles’ success is evident, most notably the small forest of dead brush that lines the Green River near the Utah entrance of the park. When I first arrived here, I wondered whether spring was late or all the trees on the bank were dead, but I never asked. After all, I was here for the dinosaurs, not the plants. Just like almost every visitor the park has.

The water tells its own story. Before the two rivers join at Steamboat Rock, the Green is dammed at Flaming Gorge, near the Wyoming/Utah border, for electricity production, and its flow is tightly regulated through Dinosaur. It flows north-south into the monument through the dramatic-sounding (and looking) Gates of Lodore. The Yampa, which we floated onto in three sturdy National Park Service rafts on Friday morning, flows east to west, entering the monument near Deerlodge Park in Colorado. After the confluence, the joined waterway winds southwest and eventually into the Colorado River.

“Make sure when you get back to Dan Chure’s office,” Tamara said with a grin as we approached the boat launch on the first day, “you tell him, ‘We saw what Dinosaur is really all about.’” While the fossils under Chure’s purview remain the Monument’s primary attraction, it also features two great rivers, the Green and the Yampa, which converge at a towering example of geology called Steamboat Rock. Elliott, Marie and I had hiked up Harper’s Corner Trail to get a view of it from above earlier in the week, and we were all excited to see what it looked like from water level.

Everyone who talks about the Yampa points out that it’s the “last natural” or “last un-dammed” tributary of the Colorado. In fact, it’s the only major river in the Colorado River system that remains unregulated. The close proximity of the Yampa and the Green allows them to be compared in a sort of ecological twin study: The differences of the two similar rivers, one regulated and the other unregulated, have given researchers vast amounts of knowledge about the effects of river flow regulation.

I’d like to say I learned the difference from water level, but to be honest, all I noticed was a color change from greenish-brown to orangish-brown. The Yampa was high, a fact no doubt related to the relentless thunderstorms that soaked us throughout our trip. The Green was also high, because water had been intentionally released earlier in the week. High water can be good news for boaters, since it broadens channels, speeds up travel, and smooths out rapids. Much higher than we saw it, however, and rapids like Warm Springs scare even the most experienced rafters.

The day we crossed Warm Springs Rapid, I had never seen at its worst. It looked insane enough to me in so-called easy mode, as I watched the careening Yampa crash across its boulders from a rocky, cottonwood-lined shore. I walked back to the boat, adrenaline already prepping my system for a possible fight against the frigid current. Stay horizontal, swim defensively, breathe between waves, I repeated to myself. I strapped my little blue helmet on tight, room for two fingers under the chin just like I was told, and wondered how easy it was to swim with it on. I tightened my PFD (personal flotation device), which I still thought of in the back of my mind as a lifejacket.

Stay horizontal, swim defensively, breathe between waves, I repeated to myself.

“Hold on to two straps and wedge your foot into the side of the boat floor,” Marie told me as she stepped into Patrick’s boat with Elliot. Tamara had her boat loaded up with bags of trash and leafy spurge, another invasive plant we were pulling from the banks of the Yampa, with no room left for a passenger. I was with Peter.

Peter and I pulled out first and headed for the rapids. I wish I could tell you the names of the holes and boulders that we dodged in the precise order Peter described them (one of the holes was definitely named “Godzilla”), but my experience was more along the lines of: terror, splash, terror, splash, wait that’s it? My boatman handled the raft so deftly that I barely got wet. I had an inkling then of just how masterful our rowers were.

one of the holes was definitely named “Godzilla”

The water calmed as we floated downstream. Our boats regrouped with giddy laughter, passengers waving and grinning to each to other across the water.

I only began to realize the true skill level of the Weed Warriors when Peter let me take the oars. I was excited to be more than a mere passenger for a change and eagerly traded places with him. The first thing that struck me was how heavy they were. The second thing was how hard they were to control. The preferred orientation for a river raft is forward, with oar strokes that push the handles ahead and pull the ends backward against the force of the current to propel the raft. By looking downstream, a river raft rower can see what’s coming and better dodge obstacles. One surprise hole could mean disaster to someone rowing backward with standard pull strokes.

Rowing a river raft was nothing like kayaking or canoeing. This was heavy, bulky equipment that had to be maneuvered in specific ways at specific times and pushed against a current so strong we were advised not to stand more than calf-deep in it. We were being pushed over a subsurface obstacle course that could drown us, steering by the tips of two mop handles. I lasted five minutes before my left arm wilted and I thought I might lose an oar. Yet Peter, Tamara and Patrick were able to do this for hours, through rapids, keeping us and all our camping and weed-pulling gear safe and surprisingly dry.

We were being pushed over a subsurface obstacle course that could drown us, steering by the tips of two mop handles.

I realized over the course of the trip how deeply imcomplete my first impressions of Tamara and Peter had been. My first sight of Tamara was at the podium of a surprisingly engaging Powerpoint presentation on hantavirus prevention a few days before, and I’d been introduced to Peter at the all-employee lunch, where he looked at me through round, thin-rimmed glasses as we discussed cameras and methods for storing mine on the boat. On the river, Tamara’s easy command of an auditorium turned into effortless command of campsites and worksites alike. Under a broad-brimmed National Parks hat, Peter transformed from stern professor to a deadpan Indiana Jones.While eating lunch on the boat on day two, I asked if anyone had a knife so I could open a package of cheese I was struggling with. Without a word, Tamara pulled a large double-edged blade out of a holster on her PFD, and handed it to me. I tried to play it cool and remember what my dad had taught me about handing knives back handle-first. Secretly, I wondered how many decades ago the last time she’d had trouble opening anything was.

Patrick is equally hardcore for his years, which are roughly equal to mine. This was only his second trip on the Yampa, but he was no stranger to rowing. A few years ago, he made international news rowing a boat across the Atlantic Ocean. Rivers have their own tricks, but it’s safe to say the Yampa was not exactly a challenge for him. He also made a mean chicken and caper pasta at our first camp site.

Our hosts made sure we never went hungry. Breakfast was early and hearty, the standout being Tamara’s ham, pineapple and fried egg breakfast sandwiches, which I wish I was eating right now in the worst way. Breakfast burritos with real Hatch green chiles ran a close second. Dinner ranged from Patrick’s pasta to Peter’s venison stew (made from a wild deer he killed himself) to Tamara’s savory mushroom and artichoke ravioli, a plate of which would have been at home on a white tablecloth with candlelight, but we enjoyed it on our beach chairs watching the shade of the canyon wall sweep across the river as the sun lowered.

Sunsets and elaborate meals weren’t the only things we enjoyed. Between pulling leafy spurge on our knees, digging out tamarisk in the rain, and setting up and breaking down camp, we had just enough time to explore some small pieces of the canyon wilderness. Each campsite was unique and left us with a new take on the river ecosystem. It was also a surprise: every time we asked, “Where next?” the only answer was “downstream.”

Wildlife was everywhere. In addition to bighorn scattered along the canyon slopes, we saw an incredible variety of insects and spiders. A scorpion caught me off-guard as I gathered rocks to hold down my tent stakes in case of sudden wind gusts (a genuine safety concern when you’re zipped up next to a body of water). Canada geese floated casually beside us, trailing fluffy lines of goslings. Common mergansers were everywhere, the strikingly different males and females often paddling together along the shore. Songbirds and swallows filled the air, turkey vultures cast their shadows on the canyon walls above us, and small brown bats hunted in the afternoons and evenings. We all stood and watched one of the bats for several minutes as it flitted and dodged above an eddy near one of our beach stops.

every time we asked, “Where next?” the only answer was “downstream.”

When Tamara wasn’t keeping our collected weeds and trash (which included half an old metal boat someone had deserted) tied down in her bow, Elliot was her regular passenger, and the beneficiary of her extensive botanical knowledge. He seized the opportunity to learn everything he could about Dinosaur’s plant species. I wish I’d overheard them, but at least I became intimately familiar with one plant: leafy spurge. We wore protective work gloves while pulling it, not because our delicate non-rower’s hands were unused to the rough surfaces found away from touchscreens and libraries, but because the weed oozes a white latex that causes blisters and permanent blindness if you happen to rub your eye after picking it. Between that and the tamarisk’s tendency to jab faces with its thin branches, I realized the name “Weed Warriors” is no exaggeration. The plants fight back.

In Peter’s boat, I learned more about the human history of the canyons. He pointed out the ruins of log cabins and corrals used to round up feral horses when Utah was a true frontier. He told me the story of Martha’s Peak, a dark pyramid of pine and stone that towered over the canyon. It was named after a feral horse who grazed there, whose foals were highly prized by the local ranchers.

Before the ranchers, a lone hunter and trapper named Denis Julien carved his initials into a rock we stopped at, along with the year: 1838.

Before even “DJ,” the Fremont people carved their own symbols in the canyon walls: shields, sheep and buffalo that Peter pointed out to me every time we passed them. And before even the Fremont, another ancient people called the canyons home. They left red figures and faces painted under overhangs more than five thousand years ago.

Before any people, before even the dinosaurs the monument is famous for, the stone of the cliffs was made. We caught a glimpse into each past world preserved in the rocks as we floated under them. The most prevalent formations on our route were the Morgan and Weber, both dating from the Pennsylvanian segment of the Carboniferous period, which ended almost 300 million years ago. The older of the two, the Morgan, alternates in mostly-horizontal bands of reddish sandstone, lavender limestone, and deep red chert, interspersed with marine fossils. The colorful canyon walls of the Morgan tell a story of a sea whose shoreline shifted in and out, forming limestone and chert when the water was deep and leaving sandy beaches when it receded. The beach sand compressed over ages, forming the sandstone bands.

The golden-yellow Weber sandstone above it tells a dramatically different story. Its smooth, stain-streaked walls reveal a world ruled by enormous sand dunes, blown into thin criss-crossing layers by the wind. At the end of the Carboniferous, this land would have resembled the Sahara. Sand collected here long enough to form the Grand Overhang, which our guides made into a highlight of the trip.

“Lie down on the box,” Peter told me, referring to the metal storage bench I sat on that was clamped into the frame of the raft. I cautiously obliged. As I looked up, the yellow wall of the Grand Overhang lived up to its name, grandly hanging into the center of my vision until it cut off in a curved line and the blue sky took over, drawing my eyes to the other wall of the canyon. I realized I could see the entire sky at once, a blue and white jellybean framed by trees and sandstone.

Below the Weber and Morgan lies the Madison limestone, a gray Carboniferous sea floor known to preserve ripples and brachiopod fossils. Under the Madison lies the Lodore, a horizontally striped remnant of the Cambrian. Even older than the Lodore is the imposing Uinta Mountain Group. Formed half a billion to a billion years ago, the most ancient rock formation in Dinosaur towered above us as we left our fourth campsite. Under the blanket-like layers of the Lodore, the Uinta Mountain Group forms uneven towers that once stood over the crashing waves of a long-gone sea. “This was like the Oregon Coast or Northern California then,” Peter told me. The analogy ends at the sea stacks; unlike my home turf on the West Coast, this Precambrian shore held no highways, no convertibles, no grazing elk, no swaying grass, no trees. When the Uinta Mountain Group was fresh new land, the only life on Earth was confined below the waves. Its sea stacks were the gates to a barren continent, still waiting for the first brave lichen to explore it.

This vast and complex history grew familiar as I floated from worksite to campsite to worksite. It dominated my thoughts, when I had time to think. The context it gave to our war against weeds was confusing at first. This land has gone from ocean to desert and back, I thought. Who are we to say what’s “native” or “invasive” in the scheme of things? Who are we to say that the new ecosystem the tamarisk and spurge create is invalid, while the one of willow and cobble-spawning fish is worth preserving?

I’m not the only who’s asked these questions. Some of the biggest issues in ecology are the hard choices between restoring native ecosystems and accepting the changes that human-introduced species have wrought, trying our best to ease the transition into the future in a way that gives the old guard at least a chance to adapt. The Weed Warriors, now that they’re established, will be able to prevent new invasions and eradicate burgeoning ones, but the war against the tamarisk is one they never expected to win.

Some of the biggest issues in ecology are the hard choices between restoring native ecosystems and accepting the changes that human-introduced species have wrought

As Peter and Tamara told us, it was hopeless when they started. Boaters would scoff when they brought up the tamarisk problem. They’d lost many campsites over the decades of invasion, and some shores were so thick with tamarisk that it was hard to tell there had ever been a beach there at all. Years of strategic removal, hard work and collaboration with volunteers and the local community paid off, though. By the time Elliott, Marie and I had the opportunity to join the Weed Warriors for our brief interlude on the river, boaters who passed us and noticed our National Park rafts were cheering us on and yelling, “Go get that tamarisk!” At half the sites where we stopped to pull spurge, a volunteer group called Friends of the Yampa had been there before us, reducing our work to a few sprouts they missed. I speak for all three of the GeoCorps interns on the trip when I say we would go out there again in a heartbeat to help as much as we could.

For me, the motivation for this work became more than the feeling of accomplishment as I fell asleep exhausted from a long day of work, and more than the camaraderie that the group gave me. I’ve had both of those working in air-conditioned offices for advertising clients, and they weren’t enough to keep me from seeking something deeper in my pursuit of science. After days studying the changes of deep time written in the canyon walls, it became the context of history that gave this work meaning.

The same observations that made me question the long-term worth of a war on weeds now justified it. As I imagined the lives of the trappers and Fremont people who once lived here, those who came before them, and the long-gone worlds of the canyon walls, it occurred to me that every past change was accidental. Our ancestors on this planet couldn’t know the consequences of their conquests, or understand the complexity of the ecosystems they moved into as they spread across the globe. They brought what they needed, wanted and carried by accident. They brought foreign fish to the Green River so they could catch something familiar, and they planted tamarisk because it pleased their eyes. In their quest to make the land suit their needs, finding a way to suit the land’s needs was a concept they would not have understood. We can’t blame them for that. But we can use what we’ve learned and built to smooth the path they first stumbled through in the dark.

The same observations that made me question the long-term worth of a war on weeds now justified it.

The goal for tamarisk in Dinosaur National Monument isn’t eradication. Like it or not, the plant is here to stay–and so are the beetles that eat it. Before the first batch of bugs was pulled out of a jar and placed by a tamarisk in Dinosaur, the ethical considerations of introducing yet another new species weighed heavily on Peter and Tamara. All of the data and technology at their disposal told them that the benefits of removing tamarisk and restoring ecosystems vital to many of the park’s endangered species was worth the marginal risk of the beetle affecting anything else. Part of that marginal risk was the danger to nesting willow flycatchers, and tamarisk beetles spread more quickly into the endangered birds’ breeding territory than predicted. There may be other consequences, but unlike the haphazard, aesthetically motivated introduction of tamarisk, the beetles will never change this entire ecosystem into something its native species can’t adapt to. We know this because it was tested, thoughtfully and painstakingly, before it was released. The beetle is now a crucial part of the new ecosystem of Dinosaur National Monument: the only predator of a future native, the tamarisk.

The beetle is now a crucial part of the new ecosystem of Dinosaur National Monument: the only predator of a future native, the tamarisk.

The Weed Warriors’ ultimate goal for this new pair of species is to have them become a stable part of the park’s ecology, filling their own niche without destroying anyone else’s. The days of the pioneers and the Fremont people are now as unreachable for this land as the windswept sand dunes of the Weber and the rippled seafloor of the Morgan Formation. That’s not necessarily a bad thing, as long as people like Tamara, Peter, and Patrick keep working hard to smooth our biosphere’s path to the future. They know that like the river, ecology only has one direction: downstream. And they row facing forward.

Originally published at on June 2, 2015.

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