Springs seepage and beaver pool complex in Grindrod B.C.

On January 18th, 2024 I set out to investigate a beaver “bank burrow” (den) site on the left bank of the Shuswap River near my home in Grindrod B.C, to see if there was any observable winter activity. Previously in late spring of 2024 I had frequented the area on walks and observed signs of beaver activity (fresh chews, tracks in mud, nearby dams). I eventually found two discreet lodge entrance tunnels high in the bank above the spring freshet high water level. Having never seen this style of beaver lodge, I was surprised to learn that beavers will opt to burrow earthen dens where it is unsuitable to build a typical lodge our of branches and mud. This particular site at a narrow bend in the river had both high velocity flows and fluctuating water levels.

My first site visit occurred at the transition from a polar vortex deep freeze, which saw temperatures dropping to -30C lows in our area. At the time of my visit daytime temperature was still a chilly -10C. As a result of the recent cold temps, the Shuswap River was completely iced over.

I accessed the site along the Shuswap Rail Trail, travelling north 333m from the Old Sicamous Rd. parking. I veered east from the trail toward the known location of the beaver burrow site (See map 1, Photo 1 – sketch). I measured the snow accumulation upslope of the river at an average of 55cm deep. Conditions were perfect for seeing tracks, as a fresh skiff of snow had fallen the day before. I looked for signs of beaver activity, which I figured was unlikely in frigid conditions. I did not see any recent beaver chew on trees or shrubs, but observed multiple deer trails and coyote tracks on route. I noted a single set of coyote tracks leading directly to the tunnel entrance (Photo 2) of the beaver den entrance tunnel (coordinates UTM 11U 351559 5613965), then meandering up the bank and back down along the frozen river edge (Photo 3). I also noticed an unusual set of tracks up the steep bank that made a trough through the snow (Photo 4). As the tracks were covered in the skiff of snow I was unable to tell if it was beaver. I speculate it might be river otter, based on the sliding track and trough formed on the slope track. It would be interesting to place a wildlife camera near the opening.

I noted that someone had wrapped several young paper birch trees near the den in chicken wire (to prevent beaver damage). The tree canopy layer consisted of Douglas fir, Paper birch, Black hawthorn, and Black cottonwood. The shrub layer consisted of Beaked hazelnut, Snowberry, Thimbleberry, Wood rose, and Saskatoon. It was not possible to ID any herb layer species with the snow cover. Though several taller species (non-native) were visible – Common tansy, Common mullein, Burdock.

I followed the coyote tracks downstream on the left bank of the river. I was shocked to come across a series of pools on the bank that had open water and vegetation visible on the edges so soon after the deep freeze. As I looked closer, I saw ripples and bubbles in the water indicating some activity within (Photo 5). During this site visit, I identified 3 such pools that seemed to be connected. I was able to climb up the hill and determined the source of water was likely seepage from a hillside spring. The water was likely collecting in the springs due to beaver activity and damming of the water. It was fascinating that the pools were open while the much larger Shuswap River was iced over. I did not have a thermometer to measure properly, but I assumed the water temps from the spring source must be warm enough despite recent ambient temps to maintain the seepage flow and pools open. I was curious about what species might take advantage of this open water for refuge or foraging.

I returned to the site of the beaver den entrance and the vicinity of the springs on January 22nd, 2024. The conditions were warmer at 1C and it was rainy and overcast. There was still plenty of snow cover. This time I focused my visit on the springs ecology, looking closer at the connectivity off seepage flow, pool, and associated (observable at this time). I identified an exposed vegetated area where the spring was flowing on a gradual slope (coordinates UTM 11U 351568 5614071), I took a couple of small plant specimens for later ID. I measured the depth of two of the largest pools as 1.5m (approx. 4m x 3m) and 60cm (approx. 1.5m x 3m). I was able to confirm that the pool formation was attributed to beaver damming with sticks and mud (Photo 6).  It was interesting that the largest pool, closest to the Shuswap River itself, appeared to have some tunneling and damming at its outlet, and the water was murky (Photo 7). It made me curious whether an animal was using it as safe passage to upland vegetation (beaver, river otter, or muskrat possibly?)

The substrate in all pools was made up of fines (silt/clay/sand). There was a lot of leaf litter/organics accumulated in and around the pools. The area I was most interested in was the seepage area where I observed water forget-me-nots and pond water starwort (water chickweed) exposed and growing amongst decomposing leaf litter (Photo 8 – sketch & Photo 9). The multi-story of vegetation here was dominated by species that tolerate and favour wet sites. The overstory was dominated by Black cottonwood and Paper birch with a few Douglas fir. The visible understory consisted of Red osier dogwood, Thimbleberry, Willow spp., Beaked hazelnut, Skunk cabbage, Reed canary grass, and Cow parsnip (limited ID with snow conditions). I also observed Sphagnum moss clumps at the nodes of branches of shrubs (Photo 10).

Additional site observations around the seepage area included bird scat containing seeds (Photo 11) and a dead immature Northern flicker near the largest pool (Photo 11).

Possible research questions to consider:

1. Are there unique species or micro-habitats that are supported by spring fed seepage areas?
2. What are the effects of springs seepage on flowering times of forget-me-nots in early spring?
3. Is the phenomenon of sphagnum moss clumps on tree branch nodes directly correlated with the springs and high site moisture?
4. Does the continuous seepage conditions of the site enhance or limit plant diversity at the herbaceous level?
5. Does the early emergence of skunk cabbage flowers influence flowering timing of surrounding plants?