Study area and site selection
All study sites were located in the boreal forest of northeastern Alberta, Canada. Sites were restricted to known caribou ranges (Alberta Environment and Parks, 2016), and were selected based on the predicted abundance of Cladonia arbuscula ssp. mitis (Alberta Biodiversity Monitoring Institute, 2018). Sites were stratified by peatland or upland jack pine stands (Pinus banksiana). Upland sites were then further stratified by time since fire, by either 0-10 years post-fire, 10-20 years post fire, 21-40 years post fire, or mature forest (Alberta Wildfire, 2018). Caribou range, predicted lichen abundance, and fire age were combined to choose sites of different stand ages. Sites were then visited in the field to ensure that lichen was present on the landscape, and that the sites were the desired ecosite types.
Map of study area
Figure 4. Study area of the project. Named areas show known caribou ranges within the study area. Caribou ranges were used to guide site selection.
Figure 5. Site locations within the study area. Sites are located within known woodland caribou ranges in northeastern and north-central Alberta. Sites are stratified by 0-10 years post-fire, 10-20 years post-fire, 21-40 years post-fire, mature forest (>40 years post-fire), and peatland. Each dot represents the location of a transect.
Field Protocols
At each site, a transect was placed at the site coordinate, and run north for 50 m. Starting at 5 m, a 1 m² hoop plot was placed every 10 m, for a total of 5 subplots. Within each subplot, percent cover of each reindeer lichen species was estimated, as well as other lichen species. An average height (in cm) was measured for each reindeer lichen species. Additional ground cover was estimated, including vascular plants, litter, bare ground, and downed woody material. Canopy cover was measured above each subplot using a spherical densiometer, and a basal area sweep was conducted at the centre of the transect, at 25 m.
For a subsample of sites, lichen was harvested to determine biomass. For harvested transects, the 5 subplots were ranked from lowest lichen cover to highest lichen cover. The lowest plot, highest plot, and a random plot were then selected for harvest. A 25 cm x 25 cm square frame was used to select an area within the selected plot that was representative of that plot's lichen cover. Cover and height were measured for the lichen within the frame, as well as other ground cover, and all reindeer lichens within the frame were harvested.
In the lab, all harvested samples were sorted in order to remove pine needles, twigs, and other debris, and then all samples were oven-dried and weighed to determine biomass.
For a subsample of sites, lichen was harvested to determine biomass. For harvested transects, the 5 subplots were ranked from lowest lichen cover to highest lichen cover. The lowest plot, highest plot, and a random plot were then selected for harvest. A 25 cm x 25 cm square frame was used to select an area within the selected plot that was representative of that plot's lichen cover. Cover and height were measured for the lichen within the frame, as well as other ground cover, and all reindeer lichens within the frame were harvested.
In the lab, all harvested samples were sorted in order to remove pine needles, twigs, and other debris, and then all samples were oven-dried and weighed to determine biomass.
Figure 6. A transect with hoop plot in a mature jack pine stand.