Dutch Lake is a popular place. Many people making use of the lake have no doubt noticed the pretty 
yellow flowers along the shoreline at certain times of the year.
The flowers are yellow flag iris. They are not native to this area and they are causing serious environmental problems to Dutch Lake and other lakes in B.C.
“The impact of yellow flag iris is multifaceted,” said Dr. Catherine Tarasoff, a researcher based at Thompson Rivers University. “It alters the whole structure of the shoreline, creating mucky islands or fingers that are not friendly to waterfowl or invertebrates. Even turtles have a hard time getting through it.”
The irises out-compete local plants, removing food sources and habitat for migratory birds and other animals.
Tarasoff is investigating ways to control the plant using “benthic barriers.”
The barriers are sheet metal boxes that are covered with old conveyer belting and then placed onto the plants, penetrating into their rhizomes.
The barriers suffocate the plants and rhizomes and block out sunlight. They also prevent other irises from growing into the space created.
Tarasoff and her research team compare the plots with the barriers with plots where the plants have been cut back, and with untreated plots.
Last summer the team set up four stations on Dutch Lake and another five on Vaseux Lake near Okanagan Falls.
“We want to test how the benthic barriers work in different environmental conditions,” said Tarasoff.
The hope is that the barriers will kill the irises and allow native plants to take over again.
Depending on the results of this year’s research, the project could be expanded to eight lakes next year.
Support for the research project has come from District of Clearwater, Thompson-Nicola Regional District, Wildlife Habitat Canada and TRU.
Further information about yellow flag iris is available at the Invasive Species Council of B.C. website: http://bcinvasives.ca/ .
