In the South Saskatchewan River Sub-basin (SSRSB), there are forty-one species of grasses and grass-like plants and seventy species of forbs.
In Reach SS-02, Cows and Fish have found the existence of extensive disturbance-caused species and invasive plants (n=66, as shown in the chart below). This suggests cumulative, longer term impacts from livestock, the intentional introduction of tame species, or perhaps, some relationship to hydrologic parameters and past flood events (e.g. creation of exposed soil and seed sources).
In Reach SS-01, Invasive plants species are also widely spread, and 62% of the area in SS-01 is covered with disturbance-caused plant species (n=62, as shown in the chart below). Native graminoid cover is good, with 25-50% cover in each examined area. The riverbank root mass protection in this area is rated from excellent to poor condition.
Note: Reach SS-02 is from the confluence of the Oldman and Bow Rivers (where they join to form the South Saskatchewan River), to the Medicine Hat gauging station. Reach SS-01 is from Medicine Hat gauging station to the Alberta / Saskatchewan border.
One of the important indicators of riparian health is the presence of native grasses. The function of the native grasses is to diminish the disturbances to the soil surface and to provide deep, binding root masses and summer and winter forage production for livestock and wildlife.
About two thirds of the area is covered with disturbance-caused plants, grasses and forbs. Most of them are smooth brome (Bromus inermis) and quack grass (Agropyron repens). The disturbance-caused plants do not have deep, binding root masses; therefore, they cannot provide stream bank protection as well as non-disturbance, native plant species.
Unfortunately, undesirable and disturbance-caused plants are abundant in the region. About 25-50% of the riparian area is covered with 50% disturbance-caused plants, and 38% of the area is covered with more than 50% disturbance-caused plants. Matters of concern in the research area include the abundance of disturbance-caused plants, the reduced quantity of native grasses and forbs and the abundance of invasive species.
Invasive plant species included bladder campion (Silene cucubalus), leafy spurge (Euphorbia esula), scentless chamomile (Matricaria perforata), Canada thistle, (Cirsium arvense), and perennial sow thistle (Sonchus arvensis).
Read more… about some of Alberta’s invasive plants (Alberta Invasive Plants Council)
Read more… about the various types and classifications of Alberta Range Plants