Year of Award

2022

Document Type

Thesis

Degree Type

Master of Science (MS)

Degree Name

Wildlife Biology

Department or School/College

W.A. Franke College of Forestry and Conservation

Committee Chair

Dr. Joshua J. Millspaugh

Commitee Members

Dr. Kelly M. Proffitt, Dr. Chad J. Bishop, Dr. Ragan M. Callaway

Keywords

Cervus canadensis, landscape nutrition model, Montana, resource selection

Publisher

University of Montana

Subject Categories

Biology

Abstract

Wildfires in the western United States have been increasing in size and severity over the last several decades, and climate forecasts suggest a continued increase in wildfire activity in the future. Large-scale wildfires often burn in a mosaic-like pattern of varying fire severity creating a heterogenous landscape with concomitant effects on vegetation communities. By changing vegetative structure, fire severity potentially alters the availability and distribution of key resources for wildlife such as food and cover, ultimately influencing habitat use. However, the impact of fire on wildlife has frequently been treated as binary (i.e., burned vs unburned), and a deeper understanding of the effect of fire severity on wildlife habitat and habitat use is needed to inform management of wildlife in recently burned landscapes. To address this gap, we sought to evaluate the effects of fire severity on summer forage quality and quantity as well as resource selection during the fall hunting seasons for female elk (Cervus canadensis).

To evaluate the effects of fire severity on summer nutritional resources, we collected field data and remotely sensed information in years two and three after a large-scale wildfire. We then built predictive forage quality and quantity models to understand the landscape level effects of fire severity. We found that both forage quality and herbaceous forage biomass increased in burned conifer forests regardless of fire severity. For shrub forage biomass, unburned forests had the highest biomass, and there was no difference between fire severities in dry forests. Low severity mesic forests had significantly greater shrub forage biomass compared to high severity burned mesic forests. Based on our predictive forage quality model, we found that wildfire extended the duration in which elk can access high quality forage.

To assess the effects of fire severity on elk habitat use in years two and three postfire during the fall hunting seasons, we developed resource selection probability function models for four hunt periods ranging from no to high hunter pressure (i.e., prehunt, archery-only, backcountry rifle, and rifle). We found limited differences in resource selection between fire severity categories during the hunting seasons in years two and three postfire. Because fire improved forage quality regardless of fire severity, elk may have been attracted to burned forests because of an increase in nutritional resources during the prehunt and archery-only periods. During the backcountry rifle and rifle periods, resource selection likely was driven by factors other than fire effects as hunter pressure and snowpack increased.

To our knowledge, our study was the first to assess the effects of fire severity on summer nutritional resources and resource selection in the fall hunting seasons for female elk. In general, we found that fire improved nutritional resources for female elk in both the summer and fall, and elk accessed the high-quality forage in burned forests when hunter pressure and snowpack on the landscape was low. We found minimal differences in nutritional resources and resource selection between low and high severity burned forests in years two and three postfire.

Download

Included in

Biology Commons

Share

COinS
 

© Copyright 2022 Lauren Ashley Snobl