Lake surveys help curb spread of AIS
Over the weekend, patches of yellow floating heart were pulled by hand from Lake Gordon in Forest County, in the Nicolet National Forest. The aggressive invasive species had been discovered in the lake earlier last week.
The incident illustrated a key side benefit emerging from a five-year effort led by the Department of Natural Resources (DNR) to survey lakes statewide for aquatic invasive species (AIS).
The surveys are allowing DNR staff, local partners and volunteers to identify early infestations of invasive species and, as they did Saturday with the yellow floating heart, take immediate steps to get rid of them before the invaders’ populations have a chance to expand.
“The surveys are having an immediate benefit, as we saw with Lake Gordon,” said Maureen Ferry, who is coordinating the survey for DNR. “We’ve had many instances where they’ve turned up new populations of invasive species that DNR and partners have been able to address immediately.”
Statewide surveys are allowing county and state staff to respond quickly when a new population of invasive species is detected, as John Preuss and Chris Hamerla did with the yellow floating heart.
Yellow floating heart is a concern because it can grow in dense patches, excluding native species, creating areas with low oxygen levels underneath the floating mats, and interfering with fishing, swimming and boating. The discovery last week of yellow floating heart in Lake Gordon is believed to be the first time the plant has been found in an inland Wisconsin lake; it had previously only been found in a few private ponds. Possession, sale, transfer and introduction of the species is illegal in Wisconsin without a permit.
John Preuss, Lumberjack Resource Conservation and Development aquatic invasives coordinator for Lincoln, Langlade and Forest counties, found the yellow floating heart mid-week when he was conducting surveys on Lake Gordon with DNR aquatic invasive species specialists Jennifer Steltenpohl and Ryan Mottiff.
Preuss returned to the lake Saturday with Chris Hamerla, AIS coordinator for the Golden Sands Resource Conservation and Development Council, and the two spent hours carefully pulling the plant from near a boat landing and campsite.
“We hand-pulled the two populations on Saturday and pulled a total of six-and-a half bags,” Preuss says. “We took our time and believe we did a good job. We made sure to get the rhizome and did our best to make sure no pieces escaped. We made sure to get under the roots and get them out of the sediment.”
Preuss will work with the U.S. Forest Service to monitor Lake Gordon and nearby lakes, and increase awareness among campers of yellow floating heart.
Surveys to detect AIS are taking place this summer on 200 randomly selected lakes with public access. The effort, funded through the federal Great Lakes Restoration Initiative, is the first of this scale in the United States and will result in more than half of Wisconsin’s 1,600 lakes with public access being monitored for invasive species, said Ferry.
Monitoring includes people in boats doing a visual survey along the entire lakeshore, snorkeling at all boat launches and at high risk locations, raking up plants to see if Eurasian water-milfoil and other plant invaders are present, and dipping nets into the water to look for invasive waterfleas and juvenile zebra mussels.
Ferry said the surveys are ultimately aimed at helping the DNR and partners know how widespread the different invasive species are and if the rate they are spreading is increasing, decreasing or staying the same. Such information can better help direct prevention and control efforts in the future, she added.
Right now, the surveys are paying off by fostering a rapid response to new discoveries when they are often more easily and less expensively addressed.