Biodiversity Study Dyke 11A

In 2006, Suncor initiated this study to evaluate effectiveness of four surface soil caps, each applied to a depth of either 25 cm or 55 cm, on tailings sand. Suncor’s standard muskeg mineral soil material (obtained by salvaging peat and 25 to 40% underlying mineral soil from areas of min 60 cm peat), was used in combination with LFH, clay and woody debris material to create the treatments. The four treatments were: 25 cm of muskeg mineral mix soil (70:30 – Suncor’s standard muskeg mineral mix); 25 cm LFH over approximately 30 cm clay; 25 cm of muskeg mineral mix soil (70:30) over 30 cm clay; and 25 cm of muskeg mineral mix soil (70:30) plus a ground cover of woody debris. Barley was planted in June 2006 and fertilized in Aug 2006, and jack pine and trembling aspen seedlings were planted in Aug 2006. Each treatment was replicated three times on the upper lift which had a 9% slope angle, and three times on the lower lift (2% slope angle) for a total of 12 treatment plots on each lift. Soil, vegetation and tree height monitoring occurred in 2006 and 2007. No monitoring occurred in 2008 and 2009. In 2010, only the treatment plots on the upper lift were monitored. Since the soil in the treatment plots on the lower lift had become saturated through water ponding, monitoring of all treatments on the lower lift was discontinued.

Flooding and high seedling mortality compromised this project, making it difficult to know whether to attribute plot differences to these factors or the treatment type. To counter this, a recommendation was made to add additional trees in 2011 to obtain a minimum of 20 jack pine and 20 trembling aspen seedlings per treatment plot to contribute more data for growth statistics and survival monitoring and assess their progress in relation to the treatment types. Continued monitoring of vegetation cover was recommended on both the upper and lower lifts to determine how soil moisture conditions in the plots affect tree and shrub growth throughout the treatments. It was also recommended that monitoring of soil moisture conditions in the upper soil horizons (0 to 100 cm depth) be undertaken to study the correlation between soil moisture conditions, percent vegetation cover and the type and number of species developing (i.e., forbs, graminoids, shrubs, trees). It is possible that continued high soil moisture conditions may eventually lead to the development of wetland successional communities rather than upland forest communities as originally planned for this study.