Anne Pearce drags weeds out of Black Earth Creek to examine for invasive species.
“Oh!” cries out Angelina Stone as she picks apart a mass of vegetation raked out of Black Earth Creek. “There is something here.”
“This is the curly-leaf pondweed,” answers Anne Pearce, who fished the invasive plant out of this area along Highway 14 just west of Cross Plains.
The pair are one of eight teams who fan out this foggy Saturday morning — Aug. 18 — searching for invasive plants for the River Alliance of Wisconsin’s fifth-annual Snapshot Day, a yearly accounting of invasive species. With rakes and binoculars, the volunteers scour the shores and nearby rivers and other waterways to assess the spread and abundance of purple loosestrife, Japanese knotweed and other invasives.
Twenty-one separate groups are surveying 172 sites across the state, from Chippewa Falls to Ashland and Sturgeon Bay. The data and pictures volunteers produce will be funneled back to the Department of Natural Resources, which manages Black Earth Creek and other fishing areas, to help them update its databases of invasive species and decide where to next limit the spread of these invaders.
Invaders like the New Zealand mudsnail, a miniscule mollusk that was discovered in Black Earth Creek in 2013, and makes the day’s surveying somewhat treacherous. River Alliance staff encourage volunteers to stay out of the water, the better to avoid spreading the hardy snail, whose all-female population is born already pregnant with some 90 offspring. Steam cleaners — the only sure way to kill the snail — are on hand to sterilize equipment.
So Pearce and Stone keep to the shoreline and a concrete bridge spanning the stream. Pearce crunches through thick brush to dip her rake into different sites of the creek, bringing back knotted vegetation for Stone to sift through. They spot what looks like Eurasian watermilfoil and bag a sample for experts to verify. Curious, they bag other unknown plants, even though they’re probably native.
A fisherman comes up, asking if Stone and Pearce have spotted any mudsnails before casting downstream. He fishes for a while, but leaves empty handed.
“We’re losing those species of fish that anglers love to go out and catch,” says Natalie Dutack, the Alliance’s watershed group manager, organizer of Snapshot Day, and self-described invasive species nerd. “We’re also losing diversity in the water, which makes the ecosystem more vulnerable to changes.”
Without any native predators, invasive populations often explode, choking out local ecosystems. The DNR teaches boaters — a primary vector for transmitting aquatic invaders — to drain and dry their boats before launching in a new lake. But some species, like the mudsnail, can survive for weeks without water, making their spread difficult to contain. So far, Black Earth Creek hosts the only known population of mudsnails in Wisconsin, and even in the entire Midwest.
During training at Festge County Park, before the field work begins, Jeff Jackson shows how native wild cucumber, which is having a banner year, can be mistaken for the invasive Japanese hops, a tenacious pest.
“Farmers tell me this will come up from the riverbank and pull down 10 rows of corn,” says Jackson, an invasive species coordinator for the Southwest Badger Resource Conservation and Development Council.
Jackson instructs the more than two dozen volunteers to be on the lookout for phragmites, Japanese knotweed and purple loosestrife, species that have been spotted in nearby Madison but not yet in this watershed.
Both Stone and Pearce are practiced hands, and it doesn’t take them long to survey four different samples. Pearce, 30, is the program coordinator for the Wisconsin First Detector Network, a citizen-science invasive-species monitoring program out of the UW Extension. After she completes the Snapshot Day surveys, Pearce takes a moment to record the presence of buckthorn and other land-based invaders for her day job.
“There are like six different terrestrial species right here,” she says. “God.”
Stone, 33, is a former event coordinator for the River Alliance who now works in the UW–Madison School of Journalism and Mass Communication. This is her second Snapshot Day. Stone thinks a lot about how protecting natural resources can bridge partisan divides. In addition to their impact on hunting and fishing, she says, invasive species have widespread economic consequences. In her thinking, a coalition of liberal and conservative residents can most effectively address invasive species.
“It’s not just the green folks who care about the environment,” she says. “It has a wide range of people that it impacts.”
Curly-leaf pondweed: A perennial aquatic plant with wavy leaves that forms dense mats interfering with waterways. Distribution: widespread.
Phragmites: Also called common reed grass, can grow up to 20 feet in dense stands. Spreads quickly underground. Distribution: All but four Wisconsin counties.
Japanese hops: An annual plant resembling beer hops with aggressive vines that grow over other plants. Distribution: Mostly southwestern counties.
Eurasian watermilfoil: Looks similar to native milfoils, growing strands with feathery leaves up to 30 feet long. Able to spread through fragments that break off. Distribution: widespread.
