Surveying for Alvars, Crevices, and Caves in Saskatchewan

We travelled to some, I should say - fairly inaccessible wilderness around Limestone Lake to get a sense for Saskatchewan's only karst region and the rare ecology found within. Here, we stumbled across many beautiful meadows and even an alvar ecosystem, only recently described within the province. To add to this, there are also some quite large cliffs and crevices around here - hikers beware!

Recent bedrock geology maps indicate this region as 'karst' geology. In other words the landscape is primarily composed of dolomite and limestone bedrock. Dolomite and limestone support unique habitat and are also capable of forming dissolution caves under the right circumstances. During this expedition we were also looking for signs of caves. To date, a true cave has not yet been documented in Saskatchewan!

Prior to a field survey, potential alvars were identified by remote sensing using Flysask2 aerial imagery. Locations which appeared to have trees growing in straight lines or criss-cross patterns were categorized as potential alvars.These forest patterns are detectable by remote sensing and result from tree rooting within bedrock cracks typical of limestone pavement.

Along the survey route, which consisted of a long canoe, and several day hike, four meadows were identified and one alvar. The mean elevation of the meadows was 336.5 m (SE = 2.36 m). Contrarily, the alvar was located slightly lower at 331 m elevation. 

Where the edge of the boreal forest and alvar ecology meet, the landscape shifts towards that of grasses and shrubs characteristic of a native prairie ecosystem. Interspersed within the prairie landscape are exposed sections of limestone bedrock.

In the meadows there is a thin layer of soil lying above the limestone pavement. As opposed to the native prairie appearance of the alvar above, there is instead a groundcover composed primarily of mosses and small-leaved plants.

Here is another viewpoint of the aforementioned alvar. At this site, there is almost no soil or surface moisture present because of the cracked limestone pavement at the surface.

There is substantial limestone bedrock underlaying the alvar habitat. The visible pockets result over time from the dissolution of carbonates. 

Here is another picture depicting the distinct dissolution patterns on a limestone boulder we found near the shores of Limestone Lake.

We found some rather large cliffs and crevices for Saskatchewan on this bushwacking trip. I won't reveal the exact location here as the ecosystems are sensitive to disturbances and host rare plant species. Nonetheless, there were quite a few of them in one area we walked through. 

Despite finding no dissolution caves on this expedition, there were indications that they may form in the area - such as deep cracks in the bedrock, small holes, and cliffs. Considering that several karst features were found in this area there may be other similar or more dramatic feature in nearby locations. Despite boasting some spectacular landscapes and diverse ecology, these areas are yet to be protected. We plan to return in the summer of 2023 for a more thorough survey of nearby areas.. more to come!