Removal of Flowering Rush August 2021

Flowering Rush is native to Eurasia and was introduced first to the eastern United States and Canada as an ornamental plant. The species was commonly imported and sold by the water garden trade, leading to the potential for illegal release into the wild. It was first recorded in North America along the shores of the St. Lawrence River near Montreal in 1897. It quickly spread into the Great Lakes and today is found in all provinces in Canada and most of the northern United States. Flowering Rush is a threat to our wetlands and riparian areas and can cause significant environmental and societal impacts. Flowering Rush displaces native plant species, impedes water flow, alters habitat structure and nutrient cycling, impacts fishing, hunting, boating, and other recreational activities. Dense patches can establish along shorelines affecting recreational users.

2021 marks the final year of funding under the Habitat Stewardship Program through Fisheries and Oceans Canada. First planning meetings were held in February 2021. We discussed possible consequences of the high river levels in 2020 and not being able to survey/remove Flowering Rush. Technical experts suggested that most likely, the plants have been washed further downstream and may have infested those areas. In June 2020 we had a meeting with the drone operator to figure out where we would need him most. It was decided that he will concentrate on areas of the river that had not been surveyed before (Cabri to Saskatchewan Landing). In July 2021 the South Saskatchewan River levels were very low and the SSRWSI coordinator went to different areas to check if surveying by canoe will still be possible. It was decided that we will continue with our field work as planned.

Between August 7-13, 2021 we surveyed the area from the Leader to the Saskatchewan Landing Regional Park. We had a larger group of people than originally expected. Therefore, we split into two different groups. One group surveyed the area from Leader to Eston Regional Park by canoe. The other group surveyed the area from Cabri Irrigation District to Cabri Regional Park. The drone operator concentrated his work on the area between Cabri Regional Park to Saskatchewan Landing.

We did not find new infestations in area between the Town of Leader and Eston Regional Park. On a windy day we went back to a location (upstream of the Town on Leader) where larger infestations have been reported in 2018 and removed plants for a stretch of approx. 2km.

Larger infestations have been found in the area between Cabri Regional Park and Saskatchewan Landing. James was very successful with his drone. He covered the area from Cabri Regional Park to Sask Landing Provincial Park.  A lot of submerged plants in the middle of the river were found. The drone works perfectly in detecting plants that are submerged and might be difficult to detect in a canoe.

Discussions were held to go back to remove plants that were detected by the drone. After talking to the drone operator it became clear that removing plants will be more difficult since most of them are in the middle of the river and submerged.

We held a debrief in October 2021, to discuss how field work went and what should be done moving forward. Some staff mentioned that the wind made it difficult to survey in canoes and to use the drone. It was also mentioned that having a Flowering Rush plant ID day would be helpful since not everyone has worked on this project before. It was also decided to apply for more funding since the plants have spread further downstream from where they were originally found. This time around we want to survey with canoes and drone and we are planning on using divers to remove plants that are submerged and not reachable by foot.

This project would not have been possible without the in-kind support from Meewasin Valley Authority, Saskatchewan Wildlife Federation, Native Plant Society of Saskatchewan, and the Ministry of Environment.