Effects of burn severity and time since fire on songbird communities in the northern boreal forest

• Main Author: Knaggs, Michelle
• Other Authors: Bayne, Erin (Biological Sciences), Nielsen, Scott (Renewable Resources)
• Format: Thesis
• Language: English
• Published: University of Alberta. Department of Renewable Resources. 2018
• Subjects: envir; geo; Canada; Northwest Territories
• Online Access: https://era.library.ualberta.ca/items/b15b79e2-06c7-4175-92c3-0faabe2622fe

Specialization: Conservation Biology Degree: Master of Science Abstract: Wildfire shapes the boreal ecosystem in western Canada and thereby enhances and diminishes important breeding habitat for many songbird species. Two aspects of wildfire, burn severity and time since fire, fundamentally alter the forest structure that songbirds use. The objectives of this study were to test the effects of burn severity (control, unburned/ low, medium, and high) one and two years post-fire and time since fire (1 to >50 years post-fire) on songbirds in the Northwest Territories, Canada. Specifically, I quantified changes in species richness, community composition, functional diversity, and species-specific responses in uplands and peatlands using data from 777 sampling stations using autonomous recording units (ARUs). Species richness and function diversity were inversely related to burn severity. Community composition converged between uplands and peatlands when burn severity was high. Both species richness and functional diversity were significantly lower one year post-fire compared to controls (>50 years post-fire). Species richness was higher than unburned controls between 3 and 50 years post-fire, while functional diversity showed no other significant changes with time since fire. There was no shift in community composition with increasing time since fire. Results suggest that burn severity, time since fire, and their interactions with vegetation type have a noticeable, but not extreme influence, on the songbird community suggesting moderate resistant and high resilience to fire disturbances. Such information may prove useful in understanding responses to songbirds under different climate change and fire scenarios and thereby inform local conservation and management actions.