Vegetation and prescribed fire: Implications for Stone's sheep and elk

Abstract

Fire is the dominant single natural disturbance influencing northern mountain and boreal landscapes. We evaluated fire-induced changes in forage resources for 2 focal ungulates, Stone's sheep (Ovis dalli stonei) and elk (Cervus canadensis), in northern British Columbia, Canada. We implemented 4 prescribed fires and monitored short-term vegetation (quantity and quality) and ungulate (Stone's sheep and elk) responses. We took measurements prior to burning, the year of burning, and 1 year after burning in treatment areas and adjacent unburned control areas in winter and summer at 2 scales. At a fine scale, we used vegetation transects and pellet counts; at the landscape scale, we used Landsat imagery for vegetation and aerial survey flights for animals. Following prescribed fire, shrub cover declined and burned communities increased in herbaceous cover. Plant species diversity also declined but increased to almost that of unburned areas by 1 year after burning. Burning increased quality of forage most (2-7 percentage points more digestibility and 0.3-6.3 percentage points more crude protein than unburned areas) in the summer of the burn. In winter, forage biomass and available digestible dry matter increased to pre-burn levels by 1 year after burning. Stone's sheep and elk always used burned areas more than unburned control areas in winter at both scales. Whereas elk used sites with higher forage quantity, Stone's sheep appeared to respond to forage quality at the fine scale. Ungulate grazing during the 2 years of this study did not alter forage quantity on burned or unburned sites, as determined from range exclosures. Based on our findings in this area, maximum benefits to elk would be achieved from large prescribed fires on south-aspect slopes that result in the greatest amounts of forage biomass. Smaller prescribed fires at high burn intensities on west-aspect slopes intermixed with rocky outcrops and talus scree (less frequented by elk) would most benefit Stone's sheep requirements for highquality forage and escape terrain. Ó 2018 The Wildlife Society.

Grazing by wild red deer maintains characteristic vegetation of semi‐natural open habitats: Evidence from a three‐year exclusion experiment

“…In the B treatment, where the frequency of red deer occurrence was intermediate, the effects of red deer exclusion on the vegetation were less conclusive than in the M treatment, although interactions between red‐deer habitat use and fire are well‐known (Proffitt et al, 2016; Sittler et al, 2019). This may partly be explained by the fact that in the first two study years burning succeeded only on three out of the five grassland study sites (Riesch et al, 2019).…”

“…This may partly be explained by the fact that in the first two study years burning succeeded only on three out of the five grassland study sites (Riesch et al, 2019). While prescribed fire has been used to enhance the quality and availability of forage for red deer in Northern America since the 1980s (Sittler et al, 2019), reasonably assessing the applicability and usefulness of a fire‐based management approach for red deer in European semi‐natural grasslands thus remains beyond the scope of the present work. Future studies should make a new attempt to assess the efficacy of burning as a means to influence the habitat use and grazing impact of red deer, because burning might be a more practical management option than mechanical biomass removal under certain conditions, e.g.…”

Sex and diel period influence patterns of resource selection in elk

“…Access to high quality herbaceous forage is one of the most significant factors influencing resource selection in many large herbivores (Schneider et al 2006, Sittler et al 2019), and proxies such as NDVI and enhanced vegetation index (EVI) are effective at identifying areas of high forage quantity and quality in many cases (Pettorelli et al 2006, Villamuelas et al 2016). For example, spring green‐up and receding snow, as measured by NDVI, is an important factor in caribou and elk migration timing, a phenomenon known as surfing the green wave (Rickbeil et al 2019, Laforge et al 2021).…”

Sequential detergent fiber assay results used for nutritional ecology research: Evidence of bias since 2012

“…For tannin‐containing plants (primarily forbs and shrubs), the protein‐binding capacity of tannins can reduce digestibility and is also included in the equation. The summative equations of digestibility have been used to study the nutritional ecology of a variety of ruminant species (Atkins et al 2019, Berry et al 2019, Sittler et al 2019, Anderson 2020, Denryter et al 2022).…”