Beneath the Surface: Assessing plant life in the lake

Long-time residents of the Lake Windermere region often comment there are more plants in the lake now than there used to be.

Long-time residents of the Lake Windermere region often comment there are more plants in the lake now than there used to be. Yet there had not been a scientific study to confirm or deny this perception until 2011, when the Lake Windermere Ambassadors made it part of our work plan to document the distribution of plants in the lake in preparation for detecting changes over time.  We were able to complete this work thanks to field research support by the BC Lake Stewardship Society, with mapping support by Selkirk College’s Geospatial Research Centre. Read on to find out what we learned.

Types of Plants

We classified the plants into four types. These include: submerged (plants under the water all the time), emergent (plants with their tops out of the water like reeds and sedges), floating (yellow pond lily and others with their leaves floating on the lake surface); and, although not technically a plant, the rooted green algae Chara spp. was also documented in this study.

Where the Plants Are

In the north section of the lake between Athalmer and the Windermere Cemetery, submerged aquatic plants were found between the shore and up to 60 metres out into the lake.

On the west side of the lake near the outlet of Goldie Creek, a diverse community of reeds, floating yellow pond lilies, floating leaf pondweed and submerged plants was present. The researchers observed plants at 200 metres from shore, but not as far as 275 metres from shore.

The east side of the lake, below Akisqnuk First Nation land, had abundant and diverse vegetation. In this area, researchers found sedges, reeds and submerged plants. Vegetation was dense at 170 metres from the shore, and sparse at about 230 metres from the shore.

In the south end of the lake, the tall rooted plant Richardson’s Pond Weed dominates. This tall plant can grow over a metre tall under water. The surveyors had a difficult time determining the extent of this plant community because, in the deeper parts of the lake, the water was too murky to determine if the plants were growing underwater. They confirmed these plants covered the lake bottom east to west across the entire lake at least two kilometres north of the south end of the lake.

The rooted algae, Chara, was found at all sample sites and presumed to occur throughout the lake. When the Lake Windermere Ambassadors take water samples in even the deepest part of the lake near Timber Ridge, we usually pull up Chara with our anchor. Chara is typical of muddy-bottomed lakes receiving water from limestone mountains like the Rockies.

What Is Changing?

Now that we have detailed maps of lake vegetation, if we go back and survey the plants again, we can compare 2011 data with current data to see if there has been any change in species presence, abundance or distribution.

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If you’re interested in learning more about this survey, or in helping with future plant surveys, get in touch with the Lake Windermere Ambassadors at 250-341-6898 or info@lakeambassadors.ca.

Kirsten Harma is the program co-ordinator for the Lake Windermere Ambassadors. She can be reached by phone at 250-341-6898 or by email at info@lakeambassadors.ca.

Invermere Valley Echo

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