Microfibers & invasive plant species — conservationists have their work cut out for them at White Rock Lake

Ian Seamans gives a short, “tsk, tsk,” as he comes across a gaggle of plump, unbothered geese sunbathing along the shoreline of White Rock Lake.

The birds aren’t supposed to gather in such a large, leisurely flock, he laments. He points to one especially round bird, whose feathers inadvertently fan outwards in a display known as angel wings, as an example of one goose who has had more than enough food given to it by well-meaning humans. Then he mutters something about “E. coli.”

“When you get this many ducks and geese that are not leaving and stay here continuously, which is a result of (human) feedings, that’s when we start having so many shoreline and water quality issues,” Seamans says.

He gives a shake of the head, further pointing out the “exacerbated erosion issues” the stationary flock has caused near the Bath House Cultural Center, before grabbing a clean water testing jar from his car’s trunk. Seamans, an environmentalist who commonly advocates for issues like clean water and air at Dallas City Hall on behalf of the organization Environment Texas, keeps a mobile laboratory in the boot of his car. On days he plans to test water quality from any number of North Texas waterways, he dresses from head to toe in natural fibers to ensure there is no chance of cross-contamination.

Still, by this point, he knows what he is likely to find.

Jars of seemingly clear water have, time and time again, shown evidence of microplastic pollution. From rivers like the Trinity, to ponds along Texas’s coast, to White Rock Lake itself, plastics the size of a grain of rice or smaller have become a ubiquitous part of Texas’s water supply. Earlier this summer, Seamans authored a study that tested 77 waterways across the state for microplastics in the forms of microfibers, microfragments, microfilms and hard pellets.

The pollution was found in 76 of those test sites, including at White Rock Lake. The water sample from White Rock Lake was taken in May of this year and tested positive for microfibers, the most common form of the pollution. The fibers most commonly come from fast fashion clothing, which uses synthetic fabrics that can enter the water cycle during machine washes or when disposed of.

“At first, we were surprised (when we found a sample with microplastics), and then we were surprised whenever we found one that didn’t have one,” Seamans says. “The one (site) that didn’t have microplastics, we’re planning on going back and retesting that site in the near future just to see if there are any that we just didn’t catch there.”

Microplastics now represent the latest in a string of battles conservationists like Seamans are waging in an attempt to keep the Lone Star State’s green spaces clean.

Upshore, fighting back against the invasive species choking out the rare remaining pockets of Dallas’s Blackland Prairie is another fight underway. According to Brett Johnson, an urban biologist and conservation manager for the City of Dallas, it’s going to take “an army.” 

Conservationists on the Prairie

The ecological goldmine that encouraged pioneers to put down roots in Texas — that nutrient-dense, fertile blackland soil that promised to grow whatever was planted — is nearly extinct. Environmentalists believe that less than 1% of the original Texas Blackland Prairie remains intact today, the majority of the ecosystem whittled away by development and farming over the centuries.

At White Rock Lake, though, the ecosystem has been preserved in 14 precious pockets scattered around the park. A scourge of invasive species, along with the eradication of natural management strategies such as fire, makes caring for each patch a somewhat tedious task.

Mowing, for instance, has to occur on an irregular schedule to mimic the irregular cycle of natural disturbances for the ecosystem. In wet years, Johnson delays the fall mowings until after the monarch butterfly migration; in dry years, like this one has been, he starts cutting back the prairie grasses a bit earlier. He tracks which month each patch gets mowed in, too, to ensure the disturbance isn’t repeated too closely year to year.

Back in the day, wildfires would have naturally created that ecological cleansing. Some native plants even have seeds whose growth is triggered by the blaze. Nearby development, though, has made fire an unpopular option for treating the area.

“Smokey the Bear did a little too good a job, because prescribed fire actually works really well for a lot of ecosystems,” says Johnson. “That’s how they evolved over millions of years, alongside fire. So now in a place like this, that’s why we’re talking about herbicides and mowing (schedules) and things like that, to knock back these species that would otherwise be knocked back by fire.”

What fire does little to help, though, are invasive species.

Johnson grass is enemy No. 1, says the City conservationist, who, by a stroke of irony, shares his name with the species. Johnson grass visually mimics native grasses, but it tends to grow thicker and faster without offering native wildlife the nutrient benefits they have evolved for. Its speedy growth means it also thrives after a disturbance, so treatment is best handled with chemicals or by physical volunteers.

To “effectively hammer the invasives,” 80 to 100 volunteer hours are needed per acre per month, Johnson says. Interest tends to dry up the moment temperatures get above 85 degrees, and there are only so many City employees who can be deployed in a given month to treat the species chemically. That leaves Johnson fighting a war of attrition against Johnson grass, although some community members have taken it upon themselves to help.

For the last seven years, Brenda Catlett has taken personal responsibility for a patch of prairie near the Bath House Cultural Center, putting her Master Naturalist knowledge to use in restoring the mosaic of grassland.

She and her husband tromp through the tall grasses several mornings a week and work to unroot the invasive species affecting the area. She’s been especially successful at eradicating a wave of Queen Anne’s Lace, a tall, white-flowered plant native to Eurasia, that had taken over the area. In the early days, some passersby reported Catlett to the City, irritated that “some lady was out there pulling out the pretty flowers.”

It’s a thankless but necessary fight. Walking through the area on a day in August, Catlett spots a dried-out plant that was missed.

“Our goal is always to try to get it out before it goes to seed, but when it’s just the two of us, it’s hard,” Catlett says.

Little Changes

Many of the environmental reforms that Seamans would like to see take place need to happen at the state level. Past legislative sessions have shown little evidence that there is much political will behind reforms like single-use plastic bans or fast fashion penalties; in fact, a state court has gone as far as to rule that municipalities cannot institute bans on items such as plastic bags.

Similarly, it is perfectly legal for many of the invasive species that plague Texas’s ecosystem to be sold at plant shops and hardware stores. While the City can offer recommendations that those plants not be carried, or ask that they be labeled as invasive, any action against a private business would need to be taken by the state.

That’s where the need for education comes in. The North Texas Master Naturalists offer programming on invasive species, and they highlight native plants during an annual celebration. Change can be as easy as buying region-specific seed packages, as even purported “native wildflower seed” mixtures can invite unwelcome new species into the area.

Personal commitments to eradicating single-use plastics are no small thing, says Seamans. And on the city level, he would like to see reforms such as pledges to cease the use of single-use plastics on City property or incentives for businesses that practice more sustainably.

“Cities can also lobby the legislature that this is what they need to combat this crisis of essentially finding plastic everywhere that there is water,” Seamans says. “We need to take action on that, and if the state isn’t willing to take action, they should at least get out of the way.”

He adds that there is no undoing the pollution that has already been created. But it’s not too late for Texas to move forward in a more sustainable way.

“We have (in Texas) a lot of fossils that had sediment fall over them, and eventually they fossilized. It’s going to be kind of like that with plastic. You’re going to be able to, in a million years, look at the rock layers and see the plastic layer from humans,” Seamans says. “There’s not really a way to remove microplastics from the environment on the large scale. The best that we can do now is stop putting it into our environment as soon as possible.”