Wednesday, 23 November 2011 16:24

New invasive threat to Swift Current watershed

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By Matthew Liebenberg — This email address is being protected from spambots. You need JavaScript enabled to view it.

The battle against the latest foreign invasion of Saskatchewan soil has already started, and Shannon Garchinski is right in the middle of it.


Garchinski, who is the invasive plants co-ordinator for the Swift Current Creek Watershed Stewards, has been busy during the summer to identify Salt Cedar, an aggressive invasive alien species that appears to be spreading into Saskatchewan.

She spoke about invasive plant species in the watershed during a presentation Nov. 16 at the Saskatchewan Ministry of Agriculture in Swift Current. Her presentation was part of the Saskatchewan Prairie Conservation Action Plan’s Native Prairie Speaker Series.

“Salt Cedar is a plant that’s very new to us,” she said. “In the States, it’s been known to drain lakes and dugouts.”

The plant — a member of the Tamarisk plant family — is native to Asia and Africa. It was introduced to North America in the 1800s as an ornamental shrub, windbreak and stream bank stabilizer. It is also known as Pink Cascade. It can grow from five to 20 feet tall, depending on its location. Its bark is reddish brown and pink to white flowers appear from mid to late summer. The small and flat leaves resemble an evergreen shrub.

Due to its ability to produce a large number of seeds, it has become problematic. It is present across the United States, including North Dakota and Montana.

“So it’s only a matter of time before those plants end up making their way up into our water systems,” Garchinski said.

She referred to three locations in the province where Salt Cedar has already been found. About four plants were discovered in a gravel pit at Findlater and in 2009 a single plant was found in a dugout south of Swift Current. This past summer she spent a lot of time at a Ministries of Highways gravel pit north of Cadillac, where plants were found during a plant species survey.

Between June and September she found 44 plants during five visits.

“We entered into a contract with the Ministries of Highways to scout this area for the next five years,” she said. “We will go out and keep looking for plants. When we find plants we destroy them out there. Any plants that we find we GPS and photograph. So, we’re trying to set up a pattern, what’s happening there.”

This shrub starts to produce viable seed from its third year, when each plant can generate 600,000 seeds per year. It forms large patches which crowd out native plants. Its large taproot allows the plant to take up large amounts of water, as much as 200 gallons per day per plant. It also secretes salt from its leaves, which makes the surrounding soil unsuitable for other vegetation.

“It decreases wildlife populations,” she said. “They don’t like living near it; it does nothing for them. It doesn’t provide any habitat for them or nutrition and it has a negative effect on riparian bird populations. Riparian birds won’t live anywhere that Salt Cedar has established itself. ... You end up with a decrease in the diversity of native fauna and vegetation in those areas.”

The Swift Current Creek Watershed Stewards are working with the Missouri River Watershed Coalition to learn more about the plant. The coalition has done extensive work on Salt Cedar across six different states. An important question is if the shrub will tolerate Canada’s more extreme climate. Recent news is not good, because Salt Cedar has been found in Russia on the same latitude as Wollaston Lake in Saskatchewan.

“So we do know this plant can survive in harsher conditions,” she said. “How well is still to be determined. We just don’t know yet.”

During her presentation Garchinski also spoke about another invasive plant, Dame’s Rocket. This attractive ornamental plant from Eurasia is still sold in many garden centres and its seed is even included in wildflower seed mixes.

Dame’s Rocket has been found along the Swift Current Creek, where seeds from residential gardens will end up if they are washed into storm sewers. In May 2009, the Swift Current Creek Watershed Stewards organized a project to pull plants from a floodplain area where homes were built in the sixties. The houses have been removed since then, but an abundance of Dame’s Rocket seed remained in the seedbed.

“Every time the creek floods the water flows into that seedbed,” she said. “It disturbs that area and those seeds end up in the water going down the creek until it deposits those Dame’s Rocket seeds somewhere along the riparian area and they start to grow and establish themselves.”

In June 2009, they also cut down Dame’s Rocket at a different location along the creek. It is easy to identify and remove the plants when they are in full bloom, when it presents an attractive and fragrant display of purple, pink or white flowers. Also known as Dame’s Violet, Mother-of-the-Evening or Violet Sweet Rocket, an individual plant can produce up to 20,000 seeds. It has a longer growing season than most native plants.

Garchinski said other invasive species area also becoming a concern in the watershed.

Eurasion Water-Milfoil is an aquatic plant that grows as a big mass on the water surface. Zebra mussels can be a huge problem in water systems.

It can be transported from between watersheds as the mussels will attach itself to boat hulls.

She emphasized the importance of education and awareness to make the public aware about the negative impact of invasive species.

The  Watershed Stewards have produced pamphlets about Dame’s Rocket and Salt Cedar.

People can help to limit the spread of invasive plants by removing them from their gardens, by learning how to manage invasives and by controlling invasives on their land.

They should be mindful to clean clothing, pets and vehicles before leaving a site with invasives.

To report invasive plants or for more information, contact Shannon Garchinski at 306-778-5027 or send an e-mail to Shannon.Garchinski@ agr.gc.ca.

Information about invasive plants is available on the Swift Current Creek Watershed Stewards website at: www.sccws.com.


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