A Case of the Invasives: Wetlandkeepers at Cheam Lake

Our second Wetlandkeepers course of 2017 – the first of the year attended by our entire Wetlands Education Program (WEP) team – was a hot and sweaty success! 18 participants from  the Lower Mainland, Bowen Island, and Victoria commuted to Cheam Lake Wetlands Park for a weekend filled with sun, knowledge sharing, and lots of Yellow Flag Iris.

Friday May 26th started off in the beautiful Rosedale Traditional Community School, where we began the workshop with introductions and an overview of both wetlands ecology and the history of Cheam Lake. Before beginning the workshop, we acknowledged that we were within the traditional territory of the Cheam First Nation. “Cheam” means wild strawberry place in the Salish language; wild strawberries were once abundant in the area, and the fragrance in the air would notify visitors of their whereabouts.

5000 years ago, the Chilliwack valley experienced a landslide three times the size of the infamous Hope counterpart. The slide unearthed a substance rich in calcium carbonate and with a high alkalinity, known as marl. Marl was mined for the better part of a century in the Chilliwack area, as it was useful in balancing the acidic nature of agricultural fields. This means the Cheam Lake wetlands are a recovering feature of the landscape, built upon the tracts of the mining equipment and flooded back to a natural level to restore wildlife habitat.

doug yellow flag press
WEP team member Doug is assisted by a participant in pressing a sample of yellow flag iris.

This theme of human interference and resulting stewardship was carried on throughout the weekend. Catherine Tarasoff of Agrowest Consulting spoke of her research on the invasive Yellow Flag Iris, and of her project that we would be assisting with the following day. The invasive species utilizes underground rhizome networks for proliferation and growth, and has floating seeds that can attach themselves to and sprout on as much as a piece of driftwood. These strong competitors have taken over much of the wetlands; Catherine’s innovative research uses pond liner as a means of “suffocating” the rhizomes by both depleting carbohydrate reserves and restricting the dispersal of acetaldehyde gas. We learned how to check for the dead, dark brown rhizomes as compared to the pink colour of their healthy counterparts. Our WEP team helped assist with this project in late August 2016, which means we had the opportunity to check our plots and see their progress!

Saturday morning started off with an overview of soil testing, and our participants evaluated calibrated soil samples for percent clay, silt, and sand contents using keys and cast trials. Tamsin Baker (Fraser Valley Conservancy, South Coast Conservation Program) then gave an overview of the species at risk of Cheam Lake. The list includes Red-legged Frog, Great Blue Heron, Blue Dasher Dragonfly, Oregon Forest Snail and Western Pondhawk. The species at risk designations, federal vs. provincial legislation, and current examples of action plans were also covered. She emphasized the singularity of action plans, as opposed to covering a larger breadth of species. But, as she said, a single species plays an invaluable role in an ecosystem, and without them the health of the ecosystem is at stake. The South Coast Conservation Program is hosting a tour of restoration workshops at Cheam Lake on September 30th! For more information please click here.

We then headed into the field for an afternoon of birding, Yellow Flag Iris removal, and GPS mapping. Our third speaker, Gord Gadsen of the Fraser Valley Regional District, started the afternoon with an overview of park management, followed by a birding-by-ear tour of the wetlands. We heard song sparrows, vultures, orioles, warblers and some… vocal Canada Geese. Neil Fletcher of the BCWF WEP team then gave an overview of the Marsh Bird Monitoring Program, an out-of-province initiative he and Bird Studies Canada are bringing to BC! The program is a citizen-based initiative, where engaged birders “adopt” a certain area and regularly monitor for species of interest, such as Sora, Virginia Rail, and the Pied-billed and Red-necked Grebes. The purpose of the surveys is to create baseline data for species presence, richness, diversity, etc.; all essential information to evaluate the health of BC’s wetlands!

After birding, participants were lead through the process of cutting Yellow Flag Iris, and then placing the aforementioned barriers over the exposed rhizomes. This was a highlight of the weekend, as many agreed there was a cathartic element to chopping down the thick growth of the invasive. Once the participants made quick work of this task, we finished the day with a tutorial on GPS mapping lead by Neil and Jason.

Sunday morning started off with uploading our GPS data onto Google Maps, and then a tutorial on aerial photo interpretation. Before we went into the field, Jason Jobin of our WEP team gave a presentation on aquatic invertebrates we were likely to find at Cheam. Participants learned the difference between larvae and adult life stages, insect morphology, and invertebrate life histories, however I think most will walk away remembering the overwhelming amount of inverts who use their butts to breathe.

dip netting
The “A team” wasn’t afraid of getting a little wet for the sake of science!

Our last afternoon in the field consisted of netting for aquatic invertebrates. Interestingly participants who collected in larger, well-connected ponds were hard-pressed to find a diversity of species, and most specimens were small in size while those who netted in more remote waters found not only a higher number of species, but invertebrates of similar life stages that were comparatively larger. This demonstrates the impact that invasive species such as introduced bass and Yellow Flag Iris have on native wildlife and plant communities, and helped emphasize the importance of maintaining natural processes.

Our final activity was conducting vegetation surveys and soil sampling. We headed further into the swamp area to learn how to fill out the wetland classification forms and use both field guides and dichotomous keys to identify vegetation. Participants valued this portion of the workshop, as many wanted to test and refine their survey skills. After time spent debating leaf edges, Graminoid stems, fern bracts, and soil horizon depth the crew finished their survey forms and headed back to be awarded their certificates.

A rare sighting of a group of Giant Water Bugs!

All in all this was a successful Wetlandkeepers weekend! We wish to thank all participants for their engagement, our speakers for their knowledge, and our partners for making this possible. Special thanks goes out to Bernie for his generosity with his ice cream! For more photos please click here.

If you want to become involved at Cheam Lake Wetlands, join us for a “planting party” on June 10th! More info can be found here.

For more information about Wetlandkeepers or other WEP workshops, please contact Jason Jobin, BCWF Wetlands Education Program Coordinator at jason.jobin@bcwf.bc.ca


WK Cheam Lake Partners




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