An Initial Review of Browse Conditions on Select Properties in the Aspen Parkland Ecoregion of Alberta
Andy Murphy and Rob Corrigan
Alberta supports a diversity of ungulate species many of which rely on plant browse as an important food resource. The Resource Data Branch (RDB) and Alberta Sustainable Resource Development (ASRD) initiated an evaluation of the browse resource on the Rumsey Ecological Reserve (RER) in 1997. The resulting study completed by Ainsley (2003) demonstrated that the silverberry and wollow cover types are extremely important contributors to overall browse production and that annual browse production fluctuates dramatically. The study also suggested that preferred browse species are heavily utilized. Browse consumption exceeded annual browse production for preferred species. In 1999, the RDB and ASRD initiated an evaluation of the browse resources in four sampling blocks (Red Deer East, Camrose-Tofield, Vermilion, and Wainwright South) across the Central Parkland. This evaluation completed by Ainsley (2004) used nearly the same methods as the RER study, but examined just one transect per land parcel. The ACA contributed to these reports by assisting with fieldwork. This ACA report highlights results of the two evaluations, reports some additional browse comparisons, and identifies objectives the ACA may want to address with future browse investigations.
Evaluation of the browse resource across the Parkland Sub-region by Ainsley (2004) demonstrated that the willow-shrub cover tupe produces significantly more browse then the aspen forest cover type, and that both production and utilization are extremely variable. Maximum browse production at a single transect was more than 53 times as great as minimum production, and the maximum utilization rate (biomass-based for individual transects) was more than four times the minimum rate. The evaluation did not demonstrate significant effects of soil texture, sampling block, or canopy height on browse production. However, it is possible that differences in grazing intensity (both current and past) and/or other environmental variables (slope, aspect or canopy closure) may have obscured real differences. Conservation sites examined did not produce significantly more browse than the randomly selected sites. this suggests that past selection of conservation sites has not effectively exploited the range of productivity that exists in the Parkland.
Based on our review of the results from Ainsley (2003) and (2004), we recommend that additional efforts are required to document spatial and temporal variability in the availability of browse in the parkland region.